1 //===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file implements the Expr constant evaluator.
11 // Constant expression evaluation produces four main results:
13 // * A success/failure flag indicating whether constant folding was successful.
14 // This is the 'bool' return value used by most of the code in this file. A
15 // 'false' return value indicates that constant folding has failed, and any
16 // appropriate diagnostic has already been produced.
18 // * An evaluated result, valid only if constant folding has not failed.
20 // * A flag indicating if evaluation encountered (unevaluated) side-effects.
21 // These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
22 // where it is possible to determine the evaluated result regardless.
24 // * A set of notes indicating why the evaluation was not a constant expression
25 // (under the C++11 / C++1y rules only, at the moment), or, if folding failed
26 // too, why the expression could not be folded.
28 // If we are checking for a potential constant expression, failure to constant
29 // fold a potential constant sub-expression will be indicated by a 'false'
30 // return value (the expression could not be folded) and no diagnostic (the
31 // expression is not necessarily non-constant).
33 //===----------------------------------------------------------------------===//
35 #include "Interp/Context.h"
36 #include "Interp/Frame.h"
37 #include "Interp/State.h"
38 #include "clang/AST/APValue.h"
39 #include "clang/AST/ASTContext.h"
40 #include "clang/AST/ASTDiagnostic.h"
41 #include "clang/AST/ASTLambda.h"
42 #include "clang/AST/Attr.h"
43 #include "clang/AST/CXXInheritance.h"
44 #include "clang/AST/CharUnits.h"
45 #include "clang/AST/CurrentSourceLocExprScope.h"
46 #include "clang/AST/Expr.h"
47 #include "clang/AST/OSLog.h"
48 #include "clang/AST/OptionalDiagnostic.h"
49 #include "clang/AST/RecordLayout.h"
50 #include "clang/AST/StmtVisitor.h"
51 #include "clang/AST/TypeLoc.h"
52 #include "clang/Basic/Builtins.h"
53 #include "clang/Basic/FixedPoint.h"
54 #include "clang/Basic/TargetInfo.h"
55 #include "llvm/ADT/Optional.h"
56 #include "llvm/ADT/SmallBitVector.h"
57 #include "llvm/Support/Debug.h"
58 #include "llvm/Support/SaveAndRestore.h"
59 #include "llvm/Support/raw_ostream.h"
63 #define DEBUG_TYPE "exprconstant"
65 using namespace clang;
76 using SourceLocExprScopeGuard =
77 CurrentSourceLocExprScope::SourceLocExprScopeGuard;
79 static QualType getType(APValue::LValueBase B) {
80 if (!B) return QualType();
81 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
82 // FIXME: It's unclear where we're supposed to take the type from, and
83 // this actually matters for arrays of unknown bound. Eg:
85 // extern int arr[]; void f() { extern int arr[3]; };
86 // constexpr int *p = &arr[1]; // valid?
88 // For now, we take the array bound from the most recent declaration.
89 for (auto *Redecl = cast<ValueDecl>(D->getMostRecentDecl()); Redecl;
90 Redecl = cast_or_null<ValueDecl>(Redecl->getPreviousDecl())) {
91 QualType T = Redecl->getType();
92 if (!T->isIncompleteArrayType())
98 if (B.is<TypeInfoLValue>())
99 return B.getTypeInfoType();
101 if (B.is<DynamicAllocLValue>())
102 return B.getDynamicAllocType();
104 const Expr *Base = B.get<const Expr*>();
106 // For a materialized temporary, the type of the temporary we materialized
107 // may not be the type of the expression.
108 if (const MaterializeTemporaryExpr *MTE =
109 dyn_cast<MaterializeTemporaryExpr>(Base)) {
110 SmallVector<const Expr *, 2> CommaLHSs;
111 SmallVector<SubobjectAdjustment, 2> Adjustments;
112 const Expr *Temp = MTE->getSubExpr();
113 const Expr *Inner = Temp->skipRValueSubobjectAdjustments(CommaLHSs,
115 // Keep any cv-qualifiers from the reference if we generated a temporary
116 // for it directly. Otherwise use the type after adjustment.
117 if (!Adjustments.empty())
118 return Inner->getType();
121 return Base->getType();
124 /// Get an LValue path entry, which is known to not be an array index, as a
125 /// field declaration.
126 static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
127 return dyn_cast_or_null<FieldDecl>(E.getAsBaseOrMember().getPointer());
129 /// Get an LValue path entry, which is known to not be an array index, as a
130 /// base class declaration.
131 static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
132 return dyn_cast_or_null<CXXRecordDecl>(E.getAsBaseOrMember().getPointer());
134 /// Determine whether this LValue path entry for a base class names a virtual
136 static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
137 return E.getAsBaseOrMember().getInt();
140 /// Given an expression, determine the type used to store the result of
141 /// evaluating that expression.
142 static QualType getStorageType(const ASTContext &Ctx, const Expr *E) {
145 return Ctx.getLValueReferenceType(E->getType());
148 /// Given a CallExpr, try to get the alloc_size attribute. May return null.
149 static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) {
150 const FunctionDecl *Callee = CE->getDirectCallee();
151 return Callee ? Callee->getAttr<AllocSizeAttr>() : nullptr;
154 /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr.
155 /// This will look through a single cast.
157 /// Returns null if we couldn't unwrap a function with alloc_size.
158 static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) {
159 if (!E->getType()->isPointerType())
162 E = E->IgnoreParens();
163 // If we're doing a variable assignment from e.g. malloc(N), there will
164 // probably be a cast of some kind. In exotic cases, we might also see a
165 // top-level ExprWithCleanups. Ignore them either way.
166 if (const auto *FE = dyn_cast<FullExpr>(E))
167 E = FE->getSubExpr()->IgnoreParens();
169 if (const auto *Cast = dyn_cast<CastExpr>(E))
170 E = Cast->getSubExpr()->IgnoreParens();
172 if (const auto *CE = dyn_cast<CallExpr>(E))
173 return getAllocSizeAttr(CE) ? CE : nullptr;
177 /// Determines whether or not the given Base contains a call to a function
178 /// with the alloc_size attribute.
179 static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) {
180 const auto *E = Base.dyn_cast<const Expr *>();
181 return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E);
184 /// The bound to claim that an array of unknown bound has.
185 /// The value in MostDerivedArraySize is undefined in this case. So, set it
186 /// to an arbitrary value that's likely to loudly break things if it's used.
187 static const uint64_t AssumedSizeForUnsizedArray =
188 std::numeric_limits<uint64_t>::max() / 2;
190 /// Determines if an LValue with the given LValueBase will have an unsized
191 /// array in its designator.
192 /// Find the path length and type of the most-derived subobject in the given
193 /// path, and find the size of the containing array, if any.
195 findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
196 ArrayRef<APValue::LValuePathEntry> Path,
197 uint64_t &ArraySize, QualType &Type, bool &IsArray,
198 bool &FirstEntryIsUnsizedArray) {
199 // This only accepts LValueBases from APValues, and APValues don't support
200 // arrays that lack size info.
201 assert(!isBaseAnAllocSizeCall(Base) &&
202 "Unsized arrays shouldn't appear here");
203 unsigned MostDerivedLength = 0;
204 Type = getType(Base);
206 for (unsigned I = 0, N = Path.size(); I != N; ++I) {
207 if (Type->isArrayType()) {
208 const ArrayType *AT = Ctx.getAsArrayType(Type);
209 Type = AT->getElementType();
210 MostDerivedLength = I + 1;
213 if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
214 ArraySize = CAT->getSize().getZExtValue();
216 assert(I == 0 && "unexpected unsized array designator");
217 FirstEntryIsUnsizedArray = true;
218 ArraySize = AssumedSizeForUnsizedArray;
220 } else if (Type->isAnyComplexType()) {
221 const ComplexType *CT = Type->castAs<ComplexType>();
222 Type = CT->getElementType();
224 MostDerivedLength = I + 1;
226 } else if (const FieldDecl *FD = getAsField(Path[I])) {
227 Type = FD->getType();
229 MostDerivedLength = I + 1;
232 // Path[I] describes a base class.
237 return MostDerivedLength;
240 /// A path from a glvalue to a subobject of that glvalue.
241 struct SubobjectDesignator {
242 /// True if the subobject was named in a manner not supported by C++11. Such
243 /// lvalues can still be folded, but they are not core constant expressions
244 /// and we cannot perform lvalue-to-rvalue conversions on them.
245 unsigned Invalid : 1;
247 /// Is this a pointer one past the end of an object?
248 unsigned IsOnePastTheEnd : 1;
250 /// Indicator of whether the first entry is an unsized array.
251 unsigned FirstEntryIsAnUnsizedArray : 1;
253 /// Indicator of whether the most-derived object is an array element.
254 unsigned MostDerivedIsArrayElement : 1;
256 /// The length of the path to the most-derived object of which this is a
258 unsigned MostDerivedPathLength : 28;
260 /// The size of the array of which the most-derived object is an element.
261 /// This will always be 0 if the most-derived object is not an array
262 /// element. 0 is not an indicator of whether or not the most-derived object
263 /// is an array, however, because 0-length arrays are allowed.
265 /// If the current array is an unsized array, the value of this is
267 uint64_t MostDerivedArraySize;
269 /// The type of the most derived object referred to by this address.
270 QualType MostDerivedType;
272 typedef APValue::LValuePathEntry PathEntry;
274 /// The entries on the path from the glvalue to the designated subobject.
275 SmallVector<PathEntry, 8> Entries;
277 SubobjectDesignator() : Invalid(true) {}
279 explicit SubobjectDesignator(QualType T)
280 : Invalid(false), IsOnePastTheEnd(false),
281 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
282 MostDerivedPathLength(0), MostDerivedArraySize(0),
283 MostDerivedType(T) {}
285 SubobjectDesignator(ASTContext &Ctx, const APValue &V)
286 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
287 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
288 MostDerivedPathLength(0), MostDerivedArraySize(0) {
289 assert(V.isLValue() && "Non-LValue used to make an LValue designator?");
291 IsOnePastTheEnd = V.isLValueOnePastTheEnd();
292 ArrayRef<PathEntry> VEntries = V.getLValuePath();
293 Entries.insert(Entries.end(), VEntries.begin(), VEntries.end());
294 if (V.getLValueBase()) {
295 bool IsArray = false;
296 bool FirstIsUnsizedArray = false;
297 MostDerivedPathLength = findMostDerivedSubobject(
298 Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize,
299 MostDerivedType, IsArray, FirstIsUnsizedArray);
300 MostDerivedIsArrayElement = IsArray;
301 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
306 void truncate(ASTContext &Ctx, APValue::LValueBase Base,
307 unsigned NewLength) {
311 assert(Base && "cannot truncate path for null pointer");
312 assert(NewLength <= Entries.size() && "not a truncation");
314 if (NewLength == Entries.size())
316 Entries.resize(NewLength);
318 bool IsArray = false;
319 bool FirstIsUnsizedArray = false;
320 MostDerivedPathLength = findMostDerivedSubobject(
321 Ctx, Base, Entries, MostDerivedArraySize, MostDerivedType, IsArray,
322 FirstIsUnsizedArray);
323 MostDerivedIsArrayElement = IsArray;
324 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
332 /// Determine whether the most derived subobject is an array without a
334 bool isMostDerivedAnUnsizedArray() const {
335 assert(!Invalid && "Calling this makes no sense on invalid designators");
336 return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
339 /// Determine what the most derived array's size is. Results in an assertion
340 /// failure if the most derived array lacks a size.
341 uint64_t getMostDerivedArraySize() const {
342 assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size");
343 return MostDerivedArraySize;
346 /// Determine whether this is a one-past-the-end pointer.
347 bool isOnePastTheEnd() const {
351 if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement &&
352 Entries[MostDerivedPathLength - 1].getAsArrayIndex() ==
353 MostDerivedArraySize)
358 /// Get the range of valid index adjustments in the form
359 /// {maximum value that can be subtracted from this pointer,
360 /// maximum value that can be added to this pointer}
361 std::pair<uint64_t, uint64_t> validIndexAdjustments() {
362 if (Invalid || isMostDerivedAnUnsizedArray())
365 // [expr.add]p4: For the purposes of these operators, a pointer to a
366 // nonarray object behaves the same as a pointer to the first element of
367 // an array of length one with the type of the object as its element type.
368 bool IsArray = MostDerivedPathLength == Entries.size() &&
369 MostDerivedIsArrayElement;
370 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
371 : (uint64_t)IsOnePastTheEnd;
373 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
374 return {ArrayIndex, ArraySize - ArrayIndex};
377 /// Check that this refers to a valid subobject.
378 bool isValidSubobject() const {
381 return !isOnePastTheEnd();
383 /// Check that this refers to a valid subobject, and if not, produce a
384 /// relevant diagnostic and set the designator as invalid.
385 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);
387 /// Get the type of the designated object.
388 QualType getType(ASTContext &Ctx) const {
389 assert(!Invalid && "invalid designator has no subobject type");
390 return MostDerivedPathLength == Entries.size()
392 : Ctx.getRecordType(getAsBaseClass(Entries.back()));
395 /// Update this designator to refer to the first element within this array.
396 void addArrayUnchecked(const ConstantArrayType *CAT) {
397 Entries.push_back(PathEntry::ArrayIndex(0));
399 // This is a most-derived object.
400 MostDerivedType = CAT->getElementType();
401 MostDerivedIsArrayElement = true;
402 MostDerivedArraySize = CAT->getSize().getZExtValue();
403 MostDerivedPathLength = Entries.size();
405 /// Update this designator to refer to the first element within the array of
406 /// elements of type T. This is an array of unknown size.
407 void addUnsizedArrayUnchecked(QualType ElemTy) {
408 Entries.push_back(PathEntry::ArrayIndex(0));
410 MostDerivedType = ElemTy;
411 MostDerivedIsArrayElement = true;
412 // The value in MostDerivedArraySize is undefined in this case. So, set it
413 // to an arbitrary value that's likely to loudly break things if it's
415 MostDerivedArraySize = AssumedSizeForUnsizedArray;
416 MostDerivedPathLength = Entries.size();
418 /// Update this designator to refer to the given base or member of this
420 void addDeclUnchecked(const Decl *D, bool Virtual = false) {
421 Entries.push_back(APValue::BaseOrMemberType(D, Virtual));
423 // If this isn't a base class, it's a new most-derived object.
424 if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
425 MostDerivedType = FD->getType();
426 MostDerivedIsArrayElement = false;
427 MostDerivedArraySize = 0;
428 MostDerivedPathLength = Entries.size();
431 /// Update this designator to refer to the given complex component.
432 void addComplexUnchecked(QualType EltTy, bool Imag) {
433 Entries.push_back(PathEntry::ArrayIndex(Imag));
435 // This is technically a most-derived object, though in practice this
436 // is unlikely to matter.
437 MostDerivedType = EltTy;
438 MostDerivedIsArrayElement = true;
439 MostDerivedArraySize = 2;
440 MostDerivedPathLength = Entries.size();
442 void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E);
443 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E,
445 /// Add N to the address of this subobject.
446 void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
447 if (Invalid || !N) return;
448 uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue();
449 if (isMostDerivedAnUnsizedArray()) {
450 diagnoseUnsizedArrayPointerArithmetic(Info, E);
451 // Can't verify -- trust that the user is doing the right thing (or if
452 // not, trust that the caller will catch the bad behavior).
453 // FIXME: Should we reject if this overflows, at least?
454 Entries.back() = PathEntry::ArrayIndex(
455 Entries.back().getAsArrayIndex() + TruncatedN);
459 // [expr.add]p4: For the purposes of these operators, a pointer to a
460 // nonarray object behaves the same as a pointer to the first element of
461 // an array of length one with the type of the object as its element type.
462 bool IsArray = MostDerivedPathLength == Entries.size() &&
463 MostDerivedIsArrayElement;
464 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
465 : (uint64_t)IsOnePastTheEnd;
467 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
469 if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
470 // Calculate the actual index in a wide enough type, so we can include
472 N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65));
473 (llvm::APInt&)N += ArrayIndex;
474 assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index");
475 diagnosePointerArithmetic(Info, E, N);
480 ArrayIndex += TruncatedN;
481 assert(ArrayIndex <= ArraySize &&
482 "bounds check succeeded for out-of-bounds index");
485 Entries.back() = PathEntry::ArrayIndex(ArrayIndex);
487 IsOnePastTheEnd = (ArrayIndex != 0);
491 /// A stack frame in the constexpr call stack.
492 class CallStackFrame : public interp::Frame {
496 /// Parent - The caller of this stack frame.
497 CallStackFrame *Caller;
499 /// Callee - The function which was called.
500 const FunctionDecl *Callee;
502 /// This - The binding for the this pointer in this call, if any.
505 /// Arguments - Parameter bindings for this function call, indexed by
506 /// parameters' function scope indices.
509 /// Source location information about the default argument or default
510 /// initializer expression we're evaluating, if any.
511 CurrentSourceLocExprScope CurSourceLocExprScope;
513 // Note that we intentionally use std::map here so that references to
514 // values are stable.
515 typedef std::pair<const void *, unsigned> MapKeyTy;
516 typedef std::map<MapKeyTy, APValue> MapTy;
517 /// Temporaries - Temporary lvalues materialized within this stack frame.
520 /// CallLoc - The location of the call expression for this call.
521 SourceLocation CallLoc;
523 /// Index - The call index of this call.
526 /// The stack of integers for tracking version numbers for temporaries.
527 SmallVector<unsigned, 2> TempVersionStack = {1};
528 unsigned CurTempVersion = TempVersionStack.back();
530 unsigned getTempVersion() const { return TempVersionStack.back(); }
532 void pushTempVersion() {
533 TempVersionStack.push_back(++CurTempVersion);
536 void popTempVersion() {
537 TempVersionStack.pop_back();
540 // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact
541 // on the overall stack usage of deeply-recursing constexpr evaluations.
542 // (We should cache this map rather than recomputing it repeatedly.)
543 // But let's try this and see how it goes; we can look into caching the map
544 // as a later change.
546 /// LambdaCaptureFields - Mapping from captured variables/this to
547 /// corresponding data members in the closure class.
548 llvm::DenseMap<const VarDecl *, FieldDecl *> LambdaCaptureFields;
549 FieldDecl *LambdaThisCaptureField;
551 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
552 const FunctionDecl *Callee, const LValue *This,
556 // Return the temporary for Key whose version number is Version.
557 APValue *getTemporary(const void *Key, unsigned Version) {
558 MapKeyTy KV(Key, Version);
559 auto LB = Temporaries.lower_bound(KV);
560 if (LB != Temporaries.end() && LB->first == KV)
562 // Pair (Key,Version) wasn't found in the map. Check that no elements
563 // in the map have 'Key' as their key.
564 assert((LB == Temporaries.end() || LB->first.first != Key) &&
565 (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) &&
566 "Element with key 'Key' found in map");
570 // Return the current temporary for Key in the map.
571 APValue *getCurrentTemporary(const void *Key) {
572 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX));
573 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key)
574 return &std::prev(UB)->second;
578 // Return the version number of the current temporary for Key.
579 unsigned getCurrentTemporaryVersion(const void *Key) const {
580 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX));
581 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key)
582 return std::prev(UB)->first.second;
586 /// Allocate storage for an object of type T in this stack frame.
587 /// Populates LV with a handle to the created object. Key identifies
588 /// the temporary within the stack frame, and must not be reused without
589 /// bumping the temporary version number.
590 template<typename KeyT>
591 APValue &createTemporary(const KeyT *Key, QualType T,
592 bool IsLifetimeExtended, LValue &LV);
594 void describe(llvm::raw_ostream &OS) override;
596 Frame *getCaller() const override { return Caller; }
597 SourceLocation getCallLocation() const override { return CallLoc; }
598 const FunctionDecl *getCallee() const override { return Callee; }
600 bool isStdFunction() const {
601 for (const DeclContext *DC = Callee; DC; DC = DC->getParent())
602 if (DC->isStdNamespace())
608 /// Temporarily override 'this'.
609 class ThisOverrideRAII {
611 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
612 : Frame(Frame), OldThis(Frame.This) {
614 Frame.This = NewThis;
616 ~ThisOverrideRAII() {
617 Frame.This = OldThis;
620 CallStackFrame &Frame;
621 const LValue *OldThis;
625 static bool HandleDestruction(EvalInfo &Info, const Expr *E,
626 const LValue &This, QualType ThisType);
627 static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
628 APValue::LValueBase LVBase, APValue &Value,
632 /// A cleanup, and a flag indicating whether it is lifetime-extended.
634 llvm::PointerIntPair<APValue*, 1, bool> Value;
635 APValue::LValueBase Base;
639 Cleanup(APValue *Val, APValue::LValueBase Base, QualType T,
640 bool IsLifetimeExtended)
641 : Value(Val, IsLifetimeExtended), Base(Base), T(T) {}
643 bool isLifetimeExtended() const { return Value.getInt(); }
644 bool endLifetime(EvalInfo &Info, bool RunDestructors) {
645 if (RunDestructors) {
647 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
648 Loc = VD->getLocation();
649 else if (const Expr *E = Base.dyn_cast<const Expr*>())
650 Loc = E->getExprLoc();
651 return HandleDestruction(Info, Loc, Base, *Value.getPointer(), T);
653 *Value.getPointer() = APValue();
657 bool hasSideEffect() {
658 return T.isDestructedType();
662 /// A reference to an object whose construction we are currently evaluating.
663 struct ObjectUnderConstruction {
664 APValue::LValueBase Base;
665 ArrayRef<APValue::LValuePathEntry> Path;
666 friend bool operator==(const ObjectUnderConstruction &LHS,
667 const ObjectUnderConstruction &RHS) {
668 return LHS.Base == RHS.Base && LHS.Path == RHS.Path;
670 friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) {
671 return llvm::hash_combine(Obj.Base, Obj.Path);
674 enum class ConstructionPhase {
685 template<> struct DenseMapInfo<ObjectUnderConstruction> {
686 using Base = DenseMapInfo<APValue::LValueBase>;
687 static ObjectUnderConstruction getEmptyKey() {
688 return {Base::getEmptyKey(), {}}; }
689 static ObjectUnderConstruction getTombstoneKey() {
690 return {Base::getTombstoneKey(), {}};
692 static unsigned getHashValue(const ObjectUnderConstruction &Object) {
693 return hash_value(Object);
695 static bool isEqual(const ObjectUnderConstruction &LHS,
696 const ObjectUnderConstruction &RHS) {
703 /// A dynamically-allocated heap object.
705 /// The value of this heap-allocated object.
707 /// The allocating expression; used for diagnostics. Either a CXXNewExpr
708 /// or a CallExpr (the latter is for direct calls to operator new inside
709 /// std::allocator<T>::allocate).
710 const Expr *AllocExpr = nullptr;
718 /// Get the kind of the allocation. This must match between allocation
719 /// and deallocation.
720 Kind getKind() const {
721 if (auto *NE = dyn_cast<CXXNewExpr>(AllocExpr))
722 return NE->isArray() ? ArrayNew : New;
723 assert(isa<CallExpr>(AllocExpr));
728 struct DynAllocOrder {
729 bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const {
730 return L.getIndex() < R.getIndex();
734 /// EvalInfo - This is a private struct used by the evaluator to capture
735 /// information about a subexpression as it is folded. It retains information
736 /// about the AST context, but also maintains information about the folded
739 /// If an expression could be evaluated, it is still possible it is not a C
740 /// "integer constant expression" or constant expression. If not, this struct
741 /// captures information about how and why not.
743 /// One bit of information passed *into* the request for constant folding
744 /// indicates whether the subexpression is "evaluated" or not according to C
745 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
746 /// evaluate the expression regardless of what the RHS is, but C only allows
747 /// certain things in certain situations.
748 class EvalInfo : public interp::State {
752 /// EvalStatus - Contains information about the evaluation.
753 Expr::EvalStatus &EvalStatus;
755 /// CurrentCall - The top of the constexpr call stack.
756 CallStackFrame *CurrentCall;
758 /// CallStackDepth - The number of calls in the call stack right now.
759 unsigned CallStackDepth;
761 /// NextCallIndex - The next call index to assign.
762 unsigned NextCallIndex;
764 /// StepsLeft - The remaining number of evaluation steps we're permitted
765 /// to perform. This is essentially a limit for the number of statements
766 /// we will evaluate.
769 /// Enable the experimental new constant interpreter. If an expression is
770 /// not supported by the interpreter, an error is triggered.
771 bool EnableNewConstInterp;
773 /// BottomFrame - The frame in which evaluation started. This must be
774 /// initialized after CurrentCall and CallStackDepth.
775 CallStackFrame BottomFrame;
777 /// A stack of values whose lifetimes end at the end of some surrounding
778 /// evaluation frame.
779 llvm::SmallVector<Cleanup, 16> CleanupStack;
781 /// EvaluatingDecl - This is the declaration whose initializer is being
782 /// evaluated, if any.
783 APValue::LValueBase EvaluatingDecl;
785 enum class EvaluatingDeclKind {
787 /// We're evaluating the construction of EvaluatingDecl.
789 /// We're evaluating the destruction of EvaluatingDecl.
792 EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None;
794 /// EvaluatingDeclValue - This is the value being constructed for the
795 /// declaration whose initializer is being evaluated, if any.
796 APValue *EvaluatingDeclValue;
798 /// Set of objects that are currently being constructed.
799 llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase>
800 ObjectsUnderConstruction;
802 /// Current heap allocations, along with the location where each was
803 /// allocated. We use std::map here because we need stable addresses
804 /// for the stored APValues.
805 std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs;
807 /// The number of heap allocations performed so far in this evaluation.
808 unsigned NumHeapAllocs = 0;
810 struct EvaluatingConstructorRAII {
812 ObjectUnderConstruction Object;
814 EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object,
816 : EI(EI), Object(Object) {
818 EI.ObjectsUnderConstruction
819 .insert({Object, HasBases ? ConstructionPhase::Bases
820 : ConstructionPhase::AfterBases})
823 void finishedConstructingBases() {
824 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases;
826 void finishedConstructingFields() {
827 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields;
829 ~EvaluatingConstructorRAII() {
830 if (DidInsert) EI.ObjectsUnderConstruction.erase(Object);
834 struct EvaluatingDestructorRAII {
836 ObjectUnderConstruction Object;
838 EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object)
839 : EI(EI), Object(Object) {
840 DidInsert = EI.ObjectsUnderConstruction
841 .insert({Object, ConstructionPhase::Destroying})
844 void startedDestroyingBases() {
845 EI.ObjectsUnderConstruction[Object] =
846 ConstructionPhase::DestroyingBases;
848 ~EvaluatingDestructorRAII() {
850 EI.ObjectsUnderConstruction.erase(Object);
855 isEvaluatingCtorDtor(APValue::LValueBase Base,
856 ArrayRef<APValue::LValuePathEntry> Path) {
857 return ObjectsUnderConstruction.lookup({Base, Path});
860 /// If we're currently speculatively evaluating, the outermost call stack
861 /// depth at which we can mutate state, otherwise 0.
862 unsigned SpeculativeEvaluationDepth = 0;
864 /// The current array initialization index, if we're performing array
866 uint64_t ArrayInitIndex = -1;
868 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
869 /// notes attached to it will also be stored, otherwise they will not be.
870 bool HasActiveDiagnostic;
872 /// Have we emitted a diagnostic explaining why we couldn't constant
873 /// fold (not just why it's not strictly a constant expression)?
874 bool HasFoldFailureDiagnostic;
876 /// Whether or not we're in a context where the front end requires a
878 bool InConstantContext;
880 /// Whether we're checking that an expression is a potential constant
881 /// expression. If so, do not fail on constructs that could become constant
882 /// later on (such as a use of an undefined global).
883 bool CheckingPotentialConstantExpression = false;
885 /// Whether we're checking for an expression that has undefined behavior.
886 /// If so, we will produce warnings if we encounter an operation that is
887 /// always undefined.
888 bool CheckingForUndefinedBehavior = false;
890 enum EvaluationMode {
891 /// Evaluate as a constant expression. Stop if we find that the expression
892 /// is not a constant expression.
893 EM_ConstantExpression,
895 /// Evaluate as a constant expression. Stop if we find that the expression
896 /// is not a constant expression. Some expressions can be retried in the
897 /// optimizer if we don't constant fold them here, but in an unevaluated
898 /// context we try to fold them immediately since the optimizer never
899 /// gets a chance to look at it.
900 EM_ConstantExpressionUnevaluated,
902 /// Fold the expression to a constant. Stop if we hit a side-effect that
906 /// Evaluate in any way we know how. Don't worry about side-effects that
907 /// can't be modeled.
908 EM_IgnoreSideEffects,
911 /// Are we checking whether the expression is a potential constant
913 bool checkingPotentialConstantExpression() const override {
914 return CheckingPotentialConstantExpression;
917 /// Are we checking an expression for overflow?
918 // FIXME: We should check for any kind of undefined or suspicious behavior
919 // in such constructs, not just overflow.
920 bool checkingForUndefinedBehavior() const override {
921 return CheckingForUndefinedBehavior;
924 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
925 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
926 CallStackDepth(0), NextCallIndex(1),
927 StepsLeft(C.getLangOpts().ConstexprStepLimit),
928 EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp),
929 BottomFrame(*this, SourceLocation(), nullptr, nullptr, nullptr),
930 EvaluatingDecl((const ValueDecl *)nullptr),
931 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
932 HasFoldFailureDiagnostic(false), InConstantContext(false),
939 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value,
940 EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) {
941 EvaluatingDecl = Base;
942 IsEvaluatingDecl = EDK;
943 EvaluatingDeclValue = &Value;
946 bool CheckCallLimit(SourceLocation Loc) {
947 // Don't perform any constexpr calls (other than the call we're checking)
948 // when checking a potential constant expression.
949 if (checkingPotentialConstantExpression() && CallStackDepth > 1)
951 if (NextCallIndex == 0) {
952 // NextCallIndex has wrapped around.
953 FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
956 if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
958 FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded)
959 << getLangOpts().ConstexprCallDepth;
963 std::pair<CallStackFrame *, unsigned>
964 getCallFrameAndDepth(unsigned CallIndex) {
965 assert(CallIndex && "no call index in getCallFrameAndDepth");
966 // We will eventually hit BottomFrame, which has Index 1, so Frame can't
967 // be null in this loop.
968 unsigned Depth = CallStackDepth;
969 CallStackFrame *Frame = CurrentCall;
970 while (Frame->Index > CallIndex) {
971 Frame = Frame->Caller;
974 if (Frame->Index == CallIndex)
975 return {Frame, Depth};
979 bool nextStep(const Stmt *S) {
981 FFDiag(S->getBeginLoc(), diag::note_constexpr_step_limit_exceeded);
988 APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV);
990 Optional<DynAlloc*> lookupDynamicAlloc(DynamicAllocLValue DA) {
991 Optional<DynAlloc*> Result;
992 auto It = HeapAllocs.find(DA);
993 if (It != HeapAllocs.end())
994 Result = &It->second;
998 /// Information about a stack frame for std::allocator<T>::[de]allocate.
999 struct StdAllocatorCaller {
1000 unsigned FrameIndex;
1002 explicit operator bool() const { return FrameIndex != 0; };
1005 StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const {
1006 for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame;
1007 Call = Call->Caller) {
1008 const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Call->Callee);
1011 const IdentifierInfo *FnII = MD->getIdentifier();
1012 if (!FnII || !FnII->isStr(FnName))
1016 dyn_cast<ClassTemplateSpecializationDecl>(MD->getParent());
1020 const IdentifierInfo *ClassII = CTSD->getIdentifier();
1021 const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
1022 if (CTSD->isInStdNamespace() && ClassII &&
1023 ClassII->isStr("allocator") && TAL.size() >= 1 &&
1024 TAL[0].getKind() == TemplateArgument::Type)
1025 return {Call->Index, TAL[0].getAsType()};
1031 void performLifetimeExtension() {
1032 // Disable the cleanups for lifetime-extended temporaries.
1034 std::remove_if(CleanupStack.begin(), CleanupStack.end(),
1035 [](Cleanup &C) { return C.isLifetimeExtended(); }),
1036 CleanupStack.end());
1039 /// Throw away any remaining cleanups at the end of evaluation. If any
1040 /// cleanups would have had a side-effect, note that as an unmodeled
1041 /// side-effect and return false. Otherwise, return true.
1042 bool discardCleanups() {
1043 for (Cleanup &C : CleanupStack) {
1044 if (C.hasSideEffect() && !noteSideEffect()) {
1045 CleanupStack.clear();
1049 CleanupStack.clear();
1054 interp::Frame *getCurrentFrame() override { return CurrentCall; }
1055 const interp::Frame *getBottomFrame() const override { return &BottomFrame; }
1057 bool hasActiveDiagnostic() override { return HasActiveDiagnostic; }
1058 void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; }
1060 void setFoldFailureDiagnostic(bool Flag) override {
1061 HasFoldFailureDiagnostic = Flag;
1064 Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; }
1066 ASTContext &getCtx() const override { return Ctx; }
1068 // If we have a prior diagnostic, it will be noting that the expression
1069 // isn't a constant expression. This diagnostic is more important,
1070 // unless we require this evaluation to produce a constant expression.
1072 // FIXME: We might want to show both diagnostics to the user in
1073 // EM_ConstantFold mode.
1074 bool hasPriorDiagnostic() override {
1075 if (!EvalStatus.Diag->empty()) {
1077 case EM_ConstantFold:
1078 case EM_IgnoreSideEffects:
1079 if (!HasFoldFailureDiagnostic)
1081 // We've already failed to fold something. Keep that diagnostic.
1083 case EM_ConstantExpression:
1084 case EM_ConstantExpressionUnevaluated:
1085 setActiveDiagnostic(false);
1092 unsigned getCallStackDepth() override { return CallStackDepth; }
1095 /// Should we continue evaluation after encountering a side-effect that we
1097 bool keepEvaluatingAfterSideEffect() {
1099 case EM_IgnoreSideEffects:
1102 case EM_ConstantExpression:
1103 case EM_ConstantExpressionUnevaluated:
1104 case EM_ConstantFold:
1105 // By default, assume any side effect might be valid in some other
1106 // evaluation of this expression from a different context.
1107 return checkingPotentialConstantExpression() ||
1108 checkingForUndefinedBehavior();
1110 llvm_unreachable("Missed EvalMode case");
1113 /// Note that we have had a side-effect, and determine whether we should
1114 /// keep evaluating.
1115 bool noteSideEffect() {
1116 EvalStatus.HasSideEffects = true;
1117 return keepEvaluatingAfterSideEffect();
1120 /// Should we continue evaluation after encountering undefined behavior?
1121 bool keepEvaluatingAfterUndefinedBehavior() {
1123 case EM_IgnoreSideEffects:
1124 case EM_ConstantFold:
1127 case EM_ConstantExpression:
1128 case EM_ConstantExpressionUnevaluated:
1129 return checkingForUndefinedBehavior();
1131 llvm_unreachable("Missed EvalMode case");
1134 /// Note that we hit something that was technically undefined behavior, but
1135 /// that we can evaluate past it (such as signed overflow or floating-point
1136 /// division by zero.)
1137 bool noteUndefinedBehavior() override {
1138 EvalStatus.HasUndefinedBehavior = true;
1139 return keepEvaluatingAfterUndefinedBehavior();
1142 /// Should we continue evaluation as much as possible after encountering a
1143 /// construct which can't be reduced to a value?
1144 bool keepEvaluatingAfterFailure() const override {
1149 case EM_ConstantExpression:
1150 case EM_ConstantExpressionUnevaluated:
1151 case EM_ConstantFold:
1152 case EM_IgnoreSideEffects:
1153 return checkingPotentialConstantExpression() ||
1154 checkingForUndefinedBehavior();
1156 llvm_unreachable("Missed EvalMode case");
1159 /// Notes that we failed to evaluate an expression that other expressions
1160 /// directly depend on, and determine if we should keep evaluating. This
1161 /// should only be called if we actually intend to keep evaluating.
1163 /// Call noteSideEffect() instead if we may be able to ignore the value that
1164 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
1166 /// (Foo(), 1) // use noteSideEffect
1167 /// (Foo() || true) // use noteSideEffect
1168 /// Foo() + 1 // use noteFailure
1169 LLVM_NODISCARD bool noteFailure() {
1170 // Failure when evaluating some expression often means there is some
1171 // subexpression whose evaluation was skipped. Therefore, (because we
1172 // don't track whether we skipped an expression when unwinding after an
1173 // evaluation failure) every evaluation failure that bubbles up from a
1174 // subexpression implies that a side-effect has potentially happened. We
1175 // skip setting the HasSideEffects flag to true until we decide to
1176 // continue evaluating after that point, which happens here.
1177 bool KeepGoing = keepEvaluatingAfterFailure();
1178 EvalStatus.HasSideEffects |= KeepGoing;
1182 class ArrayInitLoopIndex {
1184 uint64_t OuterIndex;
1187 ArrayInitLoopIndex(EvalInfo &Info)
1188 : Info(Info), OuterIndex(Info.ArrayInitIndex) {
1189 Info.ArrayInitIndex = 0;
1191 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
1193 operator uint64_t&() { return Info.ArrayInitIndex; }
1197 /// Object used to treat all foldable expressions as constant expressions.
1198 struct FoldConstant {
1201 bool HadNoPriorDiags;
1202 EvalInfo::EvaluationMode OldMode;
1204 explicit FoldConstant(EvalInfo &Info, bool Enabled)
1207 HadNoPriorDiags(Info.EvalStatus.Diag &&
1208 Info.EvalStatus.Diag->empty() &&
1209 !Info.EvalStatus.HasSideEffects),
1210 OldMode(Info.EvalMode) {
1212 Info.EvalMode = EvalInfo::EM_ConstantFold;
1214 void keepDiagnostics() { Enabled = false; }
1216 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
1217 !Info.EvalStatus.HasSideEffects)
1218 Info.EvalStatus.Diag->clear();
1219 Info.EvalMode = OldMode;
1223 /// RAII object used to set the current evaluation mode to ignore
1225 struct IgnoreSideEffectsRAII {
1227 EvalInfo::EvaluationMode OldMode;
1228 explicit IgnoreSideEffectsRAII(EvalInfo &Info)
1229 : Info(Info), OldMode(Info.EvalMode) {
1230 Info.EvalMode = EvalInfo::EM_IgnoreSideEffects;
1233 ~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; }
1236 /// RAII object used to optionally suppress diagnostics and side-effects from
1237 /// a speculative evaluation.
1238 class SpeculativeEvaluationRAII {
1239 EvalInfo *Info = nullptr;
1240 Expr::EvalStatus OldStatus;
1241 unsigned OldSpeculativeEvaluationDepth;
1243 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
1245 OldStatus = Other.OldStatus;
1246 OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth;
1247 Other.Info = nullptr;
1250 void maybeRestoreState() {
1254 Info->EvalStatus = OldStatus;
1255 Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth;
1259 SpeculativeEvaluationRAII() = default;
1261 SpeculativeEvaluationRAII(
1262 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
1263 : Info(&Info), OldStatus(Info.EvalStatus),
1264 OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) {
1265 Info.EvalStatus.Diag = NewDiag;
1266 Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1;
1269 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
1270 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
1271 moveFromAndCancel(std::move(Other));
1274 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
1275 maybeRestoreState();
1276 moveFromAndCancel(std::move(Other));
1280 ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1283 /// RAII object wrapping a full-expression or block scope, and handling
1284 /// the ending of the lifetime of temporaries created within it.
1285 template<bool IsFullExpression>
1288 unsigned OldStackSize;
1290 ScopeRAII(EvalInfo &Info)
1291 : Info(Info), OldStackSize(Info.CleanupStack.size()) {
1292 // Push a new temporary version. This is needed to distinguish between
1293 // temporaries created in different iterations of a loop.
1294 Info.CurrentCall->pushTempVersion();
1296 bool destroy(bool RunDestructors = true) {
1297 bool OK = cleanup(Info, RunDestructors, OldStackSize);
1302 if (OldStackSize != -1U)
1304 // Body moved to a static method to encourage the compiler to inline away
1305 // instances of this class.
1306 Info.CurrentCall->popTempVersion();
1309 static bool cleanup(EvalInfo &Info, bool RunDestructors,
1310 unsigned OldStackSize) {
1311 assert(OldStackSize <= Info.CleanupStack.size() &&
1312 "running cleanups out of order?");
1314 // Run all cleanups for a block scope, and non-lifetime-extended cleanups
1315 // for a full-expression scope.
1316 bool Success = true;
1317 for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) {
1318 if (!(IsFullExpression &&
1319 Info.CleanupStack[I - 1].isLifetimeExtended())) {
1320 if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) {
1327 // Compact lifetime-extended cleanups.
1328 auto NewEnd = Info.CleanupStack.begin() + OldStackSize;
1329 if (IsFullExpression)
1331 std::remove_if(NewEnd, Info.CleanupStack.end(),
1332 [](Cleanup &C) { return !C.isLifetimeExtended(); });
1333 Info.CleanupStack.erase(NewEnd, Info.CleanupStack.end());
1337 typedef ScopeRAII<false> BlockScopeRAII;
1338 typedef ScopeRAII<true> FullExpressionRAII;
1341 bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1342 CheckSubobjectKind CSK) {
1345 if (isOnePastTheEnd()) {
1346 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
1351 // Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there
1352 // must actually be at least one array element; even a VLA cannot have a
1353 // bound of zero. And if our index is nonzero, we already had a CCEDiag.
1357 void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info,
1359 Info.CCEDiag(E, diag::note_constexpr_unsized_array_indexed);
1360 // Do not set the designator as invalid: we can represent this situation,
1361 // and correct handling of __builtin_object_size requires us to do so.
1364 void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1367 // If we're complaining, we must be able to statically determine the size of
1368 // the most derived array.
1369 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1370 Info.CCEDiag(E, diag::note_constexpr_array_index)
1372 << static_cast<unsigned>(getMostDerivedArraySize());
1374 Info.CCEDiag(E, diag::note_constexpr_array_index)
1375 << N << /*non-array*/ 1;
1379 CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
1380 const FunctionDecl *Callee, const LValue *This,
1382 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1383 Arguments(Arguments), CallLoc(CallLoc), Index(Info.NextCallIndex++) {
1384 Info.CurrentCall = this;
1385 ++Info.CallStackDepth;
1388 CallStackFrame::~CallStackFrame() {
1389 assert(Info.CurrentCall == this && "calls retired out of order");
1390 --Info.CallStackDepth;
1391 Info.CurrentCall = Caller;
1394 static bool isRead(AccessKinds AK) {
1395 return AK == AK_Read || AK == AK_ReadObjectRepresentation;
1398 static bool isModification(AccessKinds AK) {
1401 case AK_ReadObjectRepresentation:
1403 case AK_DynamicCast:
1413 llvm_unreachable("unknown access kind");
1416 static bool isAnyAccess(AccessKinds AK) {
1417 return isRead(AK) || isModification(AK);
1420 /// Is this an access per the C++ definition?
1421 static bool isFormalAccess(AccessKinds AK) {
1422 return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy;
1425 /// Is this kind of axcess valid on an indeterminate object value?
1426 static bool isValidIndeterminateAccess(AccessKinds AK) {
1431 // These need the object's value.
1434 case AK_ReadObjectRepresentation:
1438 // Construction and destruction don't need the value.
1442 case AK_DynamicCast:
1444 // These aren't really meaningful on scalars.
1447 llvm_unreachable("unknown access kind");
1451 struct ComplexValue {
1456 APSInt IntReal, IntImag;
1457 APFloat FloatReal, FloatImag;
1459 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1461 void makeComplexFloat() { IsInt = false; }
1462 bool isComplexFloat() const { return !IsInt; }
1463 APFloat &getComplexFloatReal() { return FloatReal; }
1464 APFloat &getComplexFloatImag() { return FloatImag; }
1466 void makeComplexInt() { IsInt = true; }
1467 bool isComplexInt() const { return IsInt; }
1468 APSInt &getComplexIntReal() { return IntReal; }
1469 APSInt &getComplexIntImag() { return IntImag; }
1471 void moveInto(APValue &v) const {
1472 if (isComplexFloat())
1473 v = APValue(FloatReal, FloatImag);
1475 v = APValue(IntReal, IntImag);
1477 void setFrom(const APValue &v) {
1478 assert(v.isComplexFloat() || v.isComplexInt());
1479 if (v.isComplexFloat()) {
1481 FloatReal = v.getComplexFloatReal();
1482 FloatImag = v.getComplexFloatImag();
1485 IntReal = v.getComplexIntReal();
1486 IntImag = v.getComplexIntImag();
1492 APValue::LValueBase Base;
1494 SubobjectDesignator Designator;
1496 bool InvalidBase : 1;
1498 const APValue::LValueBase getLValueBase() const { return Base; }
1499 CharUnits &getLValueOffset() { return Offset; }
1500 const CharUnits &getLValueOffset() const { return Offset; }
1501 SubobjectDesignator &getLValueDesignator() { return Designator; }
1502 const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1503 bool isNullPointer() const { return IsNullPtr;}
1505 unsigned getLValueCallIndex() const { return Base.getCallIndex(); }
1506 unsigned getLValueVersion() const { return Base.getVersion(); }
1508 void moveInto(APValue &V) const {
1509 if (Designator.Invalid)
1510 V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr);
1512 assert(!InvalidBase && "APValues can't handle invalid LValue bases");
1513 V = APValue(Base, Offset, Designator.Entries,
1514 Designator.IsOnePastTheEnd, IsNullPtr);
1517 void setFrom(ASTContext &Ctx, const APValue &V) {
1518 assert(V.isLValue() && "Setting LValue from a non-LValue?");
1519 Base = V.getLValueBase();
1520 Offset = V.getLValueOffset();
1521 InvalidBase = false;
1522 Designator = SubobjectDesignator(Ctx, V);
1523 IsNullPtr = V.isNullPointer();
1526 void set(APValue::LValueBase B, bool BInvalid = false) {
1528 // We only allow a few types of invalid bases. Enforce that here.
1530 const auto *E = B.get<const Expr *>();
1531 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&
1532 "Unexpected type of invalid base");
1537 Offset = CharUnits::fromQuantity(0);
1538 InvalidBase = BInvalid;
1539 Designator = SubobjectDesignator(getType(B));
1543 void setNull(ASTContext &Ctx, QualType PointerTy) {
1544 Base = (Expr *)nullptr;
1546 CharUnits::fromQuantity(Ctx.getTargetNullPointerValue(PointerTy));
1547 InvalidBase = false;
1548 Designator = SubobjectDesignator(PointerTy->getPointeeType());
1552 void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1556 std::string toString(ASTContext &Ctx, QualType T) const {
1558 moveInto(Printable);
1559 return Printable.getAsString(Ctx, T);
1563 // Check that this LValue is not based on a null pointer. If it is, produce
1564 // a diagnostic and mark the designator as invalid.
1565 template <typename GenDiagType>
1566 bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) {
1567 if (Designator.Invalid)
1571 Designator.setInvalid();
1578 bool checkNullPointer(EvalInfo &Info, const Expr *E,
1579 CheckSubobjectKind CSK) {
1580 return checkNullPointerDiagnosingWith([&Info, E, CSK] {
1581 Info.CCEDiag(E, diag::note_constexpr_null_subobject) << CSK;
1585 bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E,
1587 return checkNullPointerDiagnosingWith([&Info, E, AK] {
1588 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
1592 // Check this LValue refers to an object. If not, set the designator to be
1593 // invalid and emit a diagnostic.
1594 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1595 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1596 Designator.checkSubobject(Info, E, CSK);
1599 void addDecl(EvalInfo &Info, const Expr *E,
1600 const Decl *D, bool Virtual = false) {
1601 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
1602 Designator.addDeclUnchecked(D, Virtual);
1604 void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) {
1605 if (!Designator.Entries.empty()) {
1606 Info.CCEDiag(E, diag::note_constexpr_unsupported_unsized_array);
1607 Designator.setInvalid();
1610 if (checkSubobject(Info, E, CSK_ArrayToPointer)) {
1611 assert(getType(Base)->isPointerType() || getType(Base)->isArrayType());
1612 Designator.FirstEntryIsAnUnsizedArray = true;
1613 Designator.addUnsizedArrayUnchecked(ElemTy);
1616 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1617 if (checkSubobject(Info, E, CSK_ArrayToPointer))
1618 Designator.addArrayUnchecked(CAT);
1620 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1621 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
1622 Designator.addComplexUnchecked(EltTy, Imag);
1624 void clearIsNullPointer() {
1627 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E,
1628 const APSInt &Index, CharUnits ElementSize) {
1629 // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB,
1630 // but we're not required to diagnose it and it's valid in C++.)
1634 // Compute the new offset in the appropriate width, wrapping at 64 bits.
1635 // FIXME: When compiling for a 32-bit target, we should use 32-bit
1637 uint64_t Offset64 = Offset.getQuantity();
1638 uint64_t ElemSize64 = ElementSize.getQuantity();
1639 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
1640 Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64);
1642 if (checkNullPointer(Info, E, CSK_ArrayIndex))
1643 Designator.adjustIndex(Info, E, Index);
1644 clearIsNullPointer();
1646 void adjustOffset(CharUnits N) {
1648 if (N.getQuantity())
1649 clearIsNullPointer();
1655 explicit MemberPtr(const ValueDecl *Decl) :
1656 DeclAndIsDerivedMember(Decl, false), Path() {}
1658 /// The member or (direct or indirect) field referred to by this member
1659 /// pointer, or 0 if this is a null member pointer.
1660 const ValueDecl *getDecl() const {
1661 return DeclAndIsDerivedMember.getPointer();
1663 /// Is this actually a member of some type derived from the relevant class?
1664 bool isDerivedMember() const {
1665 return DeclAndIsDerivedMember.getInt();
1667 /// Get the class which the declaration actually lives in.
1668 const CXXRecordDecl *getContainingRecord() const {
1669 return cast<CXXRecordDecl>(
1670 DeclAndIsDerivedMember.getPointer()->getDeclContext());
1673 void moveInto(APValue &V) const {
1674 V = APValue(getDecl(), isDerivedMember(), Path);
1676 void setFrom(const APValue &V) {
1677 assert(V.isMemberPointer());
1678 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1679 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1681 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
1682 Path.insert(Path.end(), P.begin(), P.end());
1685 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1686 /// whether the member is a member of some class derived from the class type
1687 /// of the member pointer.
1688 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1689 /// Path - The path of base/derived classes from the member declaration's
1690 /// class (exclusive) to the class type of the member pointer (inclusive).
1691 SmallVector<const CXXRecordDecl*, 4> Path;
1693 /// Perform a cast towards the class of the Decl (either up or down the
1695 bool castBack(const CXXRecordDecl *Class) {
1696 assert(!Path.empty());
1697 const CXXRecordDecl *Expected;
1698 if (Path.size() >= 2)
1699 Expected = Path[Path.size() - 2];
1701 Expected = getContainingRecord();
1702 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1703 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1704 // if B does not contain the original member and is not a base or
1705 // derived class of the class containing the original member, the result
1706 // of the cast is undefined.
1707 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1708 // (D::*). We consider that to be a language defect.
1714 /// Perform a base-to-derived member pointer cast.
1715 bool castToDerived(const CXXRecordDecl *Derived) {
1718 if (!isDerivedMember()) {
1719 Path.push_back(Derived);
1722 if (!castBack(Derived))
1725 DeclAndIsDerivedMember.setInt(false);
1728 /// Perform a derived-to-base member pointer cast.
1729 bool castToBase(const CXXRecordDecl *Base) {
1733 DeclAndIsDerivedMember.setInt(true);
1734 if (isDerivedMember()) {
1735 Path.push_back(Base);
1738 return castBack(Base);
1742 /// Compare two member pointers, which are assumed to be of the same type.
1743 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1744 if (!LHS.getDecl() || !RHS.getDecl())
1745 return !LHS.getDecl() && !RHS.getDecl();
1746 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1748 return LHS.Path == RHS.Path;
1752 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1753 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1754 const LValue &This, const Expr *E,
1755 bool AllowNonLiteralTypes = false);
1756 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
1757 bool InvalidBaseOK = false);
1758 static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
1759 bool InvalidBaseOK = false);
1760 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1762 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1763 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1764 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1766 static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1767 static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1768 static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
1770 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1772 /// Evaluate an integer or fixed point expression into an APResult.
1773 static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
1776 /// Evaluate only a fixed point expression into an APResult.
1777 static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
1780 //===----------------------------------------------------------------------===//
1782 //===----------------------------------------------------------------------===//
1784 /// Negate an APSInt in place, converting it to a signed form if necessary, and
1785 /// preserving its value (by extending by up to one bit as needed).
1786 static void negateAsSigned(APSInt &Int) {
1787 if (Int.isUnsigned() || Int.isMinSignedValue()) {
1788 Int = Int.extend(Int.getBitWidth() + 1);
1789 Int.setIsSigned(true);
1794 template<typename KeyT>
1795 APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T,
1796 bool IsLifetimeExtended, LValue &LV) {
1797 unsigned Version = getTempVersion();
1798 APValue::LValueBase Base(Key, Index, Version);
1800 APValue &Result = Temporaries[MapKeyTy(Key, Version)];
1801 assert(Result.isAbsent() && "temporary created multiple times");
1803 // If we're creating a temporary immediately in the operand of a speculative
1804 // evaluation, don't register a cleanup to be run outside the speculative
1805 // evaluation context, since we won't actually be able to initialize this
1807 if (Index <= Info.SpeculativeEvaluationDepth) {
1808 if (T.isDestructedType())
1809 Info.noteSideEffect();
1811 Info.CleanupStack.push_back(Cleanup(&Result, Base, T, IsLifetimeExtended));
1816 APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) {
1817 if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) {
1818 FFDiag(E, diag::note_constexpr_heap_alloc_limit_exceeded);
1822 DynamicAllocLValue DA(NumHeapAllocs++);
1823 LV.set(APValue::LValueBase::getDynamicAlloc(DA, T));
1824 auto Result = HeapAllocs.emplace(std::piecewise_construct,
1825 std::forward_as_tuple(DA), std::tuple<>());
1826 assert(Result.second && "reused a heap alloc index?");
1827 Result.first->second.AllocExpr = E;
1828 return &Result.first->second.Value;
1831 /// Produce a string describing the given constexpr call.
1832 void CallStackFrame::describe(raw_ostream &Out) {
1833 unsigned ArgIndex = 0;
1834 bool IsMemberCall = isa<CXXMethodDecl>(Callee) &&
1835 !isa<CXXConstructorDecl>(Callee) &&
1836 cast<CXXMethodDecl>(Callee)->isInstance();
1839 Out << *Callee << '(';
1841 if (This && IsMemberCall) {
1843 This->moveInto(Val);
1844 Val.printPretty(Out, Info.Ctx,
1845 This->Designator.MostDerivedType);
1846 // FIXME: Add parens around Val if needed.
1847 Out << "->" << *Callee << '(';
1848 IsMemberCall = false;
1851 for (FunctionDecl::param_const_iterator I = Callee->param_begin(),
1852 E = Callee->param_end(); I != E; ++I, ++ArgIndex) {
1853 if (ArgIndex > (unsigned)IsMemberCall)
1856 const ParmVarDecl *Param = *I;
1857 const APValue &Arg = Arguments[ArgIndex];
1858 Arg.printPretty(Out, Info.Ctx, Param->getType());
1860 if (ArgIndex == 0 && IsMemberCall)
1861 Out << "->" << *Callee << '(';
1867 /// Evaluate an expression to see if it had side-effects, and discard its
1869 /// \return \c true if the caller should keep evaluating.
1870 static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
1872 if (!Evaluate(Scratch, Info, E))
1873 // We don't need the value, but we might have skipped a side effect here.
1874 return Info.noteSideEffect();
1878 /// Should this call expression be treated as a string literal?
1879 static bool IsStringLiteralCall(const CallExpr *E) {
1880 unsigned Builtin = E->getBuiltinCallee();
1881 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
1882 Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
1885 static bool IsGlobalLValue(APValue::LValueBase B) {
1886 // C++11 [expr.const]p3 An address constant expression is a prvalue core
1887 // constant expression of pointer type that evaluates to...
1889 // ... a null pointer value, or a prvalue core constant expression of type
1891 if (!B) return true;
1893 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
1894 // ... the address of an object with static storage duration,
1895 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
1896 return VD->hasGlobalStorage();
1897 // ... the address of a function,
1898 // ... the address of a GUID [MS extension],
1899 return isa<FunctionDecl>(D) || isa<MSGuidDecl>(D);
1902 if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>())
1905 const Expr *E = B.get<const Expr*>();
1906 switch (E->getStmtClass()) {
1909 case Expr::CompoundLiteralExprClass: {
1910 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
1911 return CLE->isFileScope() && CLE->isLValue();
1913 case Expr::MaterializeTemporaryExprClass:
1914 // A materialized temporary might have been lifetime-extended to static
1915 // storage duration.
1916 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
1917 // A string literal has static storage duration.
1918 case Expr::StringLiteralClass:
1919 case Expr::PredefinedExprClass:
1920 case Expr::ObjCStringLiteralClass:
1921 case Expr::ObjCEncodeExprClass:
1923 case Expr::ObjCBoxedExprClass:
1924 return cast<ObjCBoxedExpr>(E)->isExpressibleAsConstantInitializer();
1925 case Expr::CallExprClass:
1926 return IsStringLiteralCall(cast<CallExpr>(E));
1927 // For GCC compatibility, &&label has static storage duration.
1928 case Expr::AddrLabelExprClass:
1930 // A Block literal expression may be used as the initialization value for
1931 // Block variables at global or local static scope.
1932 case Expr::BlockExprClass:
1933 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
1934 case Expr::ImplicitValueInitExprClass:
1936 // We can never form an lvalue with an implicit value initialization as its
1937 // base through expression evaluation, so these only appear in one case: the
1938 // implicit variable declaration we invent when checking whether a constexpr
1939 // constructor can produce a constant expression. We must assume that such
1940 // an expression might be a global lvalue.
1945 static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
1946 return LVal.Base.dyn_cast<const ValueDecl*>();
1949 static bool IsLiteralLValue(const LValue &Value) {
1950 if (Value.getLValueCallIndex())
1952 const Expr *E = Value.Base.dyn_cast<const Expr*>();
1953 return E && !isa<MaterializeTemporaryExpr>(E);
1956 static bool IsWeakLValue(const LValue &Value) {
1957 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1958 return Decl && Decl->isWeak();
1961 static bool isZeroSized(const LValue &Value) {
1962 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1963 if (Decl && isa<VarDecl>(Decl)) {
1964 QualType Ty = Decl->getType();
1965 if (Ty->isArrayType())
1966 return Ty->isIncompleteType() ||
1967 Decl->getASTContext().getTypeSize(Ty) == 0;
1972 static bool HasSameBase(const LValue &A, const LValue &B) {
1973 if (!A.getLValueBase())
1974 return !B.getLValueBase();
1975 if (!B.getLValueBase())
1978 if (A.getLValueBase().getOpaqueValue() !=
1979 B.getLValueBase().getOpaqueValue()) {
1980 const Decl *ADecl = GetLValueBaseDecl(A);
1983 const Decl *BDecl = GetLValueBaseDecl(B);
1984 if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl())
1988 return IsGlobalLValue(A.getLValueBase()) ||
1989 (A.getLValueCallIndex() == B.getLValueCallIndex() &&
1990 A.getLValueVersion() == B.getLValueVersion());
1993 static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
1994 assert(Base && "no location for a null lvalue");
1995 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1997 Info.Note(VD->getLocation(), diag::note_declared_at);
1998 else if (const Expr *E = Base.dyn_cast<const Expr*>())
1999 Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here);
2000 else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
2001 // FIXME: Produce a note for dangling pointers too.
2002 if (Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA))
2003 Info.Note((*Alloc)->AllocExpr->getExprLoc(),
2004 diag::note_constexpr_dynamic_alloc_here);
2006 // We have no information to show for a typeid(T) object.
2009 enum class CheckEvaluationResultKind {
2014 /// Materialized temporaries that we've already checked to determine if they're
2015 /// initializsed by a constant expression.
2016 using CheckedTemporaries =
2017 llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>;
2019 static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2020 EvalInfo &Info, SourceLocation DiagLoc,
2021 QualType Type, const APValue &Value,
2022 Expr::ConstExprUsage Usage,
2023 SourceLocation SubobjectLoc,
2024 CheckedTemporaries &CheckedTemps);
2026 /// Check that this reference or pointer core constant expression is a valid
2027 /// value for an address or reference constant expression. Return true if we
2028 /// can fold this expression, whether or not it's a constant expression.
2029 static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
2030 QualType Type, const LValue &LVal,
2031 Expr::ConstExprUsage Usage,
2032 CheckedTemporaries &CheckedTemps) {
2033 bool IsReferenceType = Type->isReferenceType();
2035 APValue::LValueBase Base = LVal.getLValueBase();
2036 const SubobjectDesignator &Designator = LVal.getLValueDesignator();
2038 if (auto *VD = LVal.getLValueBase().dyn_cast<const ValueDecl *>()) {
2039 if (auto *FD = dyn_cast<FunctionDecl>(VD)) {
2040 if (FD->isConsteval()) {
2041 Info.FFDiag(Loc, diag::note_consteval_address_accessible)
2042 << !Type->isAnyPointerType();
2043 Info.Note(FD->getLocation(), diag::note_declared_at);
2049 // Check that the object is a global. Note that the fake 'this' object we
2050 // manufacture when checking potential constant expressions is conservatively
2051 // assumed to be global here.
2052 if (!IsGlobalLValue(Base)) {
2053 if (Info.getLangOpts().CPlusPlus11) {
2054 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
2055 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
2056 << IsReferenceType << !Designator.Entries.empty()
2058 NoteLValueLocation(Info, Base);
2062 // Don't allow references to temporaries to escape.
2065 assert((Info.checkingPotentialConstantExpression() ||
2066 LVal.getLValueCallIndex() == 0) &&
2067 "have call index for global lvalue");
2069 if (Base.is<DynamicAllocLValue>()) {
2070 Info.FFDiag(Loc, diag::note_constexpr_dynamic_alloc)
2071 << IsReferenceType << !Designator.Entries.empty();
2072 NoteLValueLocation(Info, Base);
2076 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
2077 if (const VarDecl *Var = dyn_cast<const VarDecl>(VD)) {
2078 // Check if this is a thread-local variable.
2079 if (Var->getTLSKind())
2080 // FIXME: Diagnostic!
2083 // A dllimport variable never acts like a constant.
2084 if (Usage == Expr::EvaluateForCodeGen && Var->hasAttr<DLLImportAttr>())
2085 // FIXME: Diagnostic!
2088 if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) {
2089 // __declspec(dllimport) must be handled very carefully:
2090 // We must never initialize an expression with the thunk in C++.
2091 // Doing otherwise would allow the same id-expression to yield
2092 // different addresses for the same function in different translation
2093 // units. However, this means that we must dynamically initialize the
2094 // expression with the contents of the import address table at runtime.
2096 // The C language has no notion of ODR; furthermore, it has no notion of
2097 // dynamic initialization. This means that we are permitted to
2098 // perform initialization with the address of the thunk.
2099 if (Info.getLangOpts().CPlusPlus && Usage == Expr::EvaluateForCodeGen &&
2100 FD->hasAttr<DLLImportAttr>())
2101 // FIXME: Diagnostic!
2104 } else if (const auto *MTE = dyn_cast_or_null<MaterializeTemporaryExpr>(
2105 Base.dyn_cast<const Expr *>())) {
2106 if (CheckedTemps.insert(MTE).second) {
2107 QualType TempType = getType(Base);
2108 if (TempType.isDestructedType()) {
2109 Info.FFDiag(MTE->getExprLoc(),
2110 diag::note_constexpr_unsupported_tempoarary_nontrivial_dtor)
2115 APValue *V = MTE->getOrCreateValue(false);
2116 assert(V && "evasluation result refers to uninitialised temporary");
2117 if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
2118 Info, MTE->getExprLoc(), TempType, *V,
2119 Usage, SourceLocation(), CheckedTemps))
2124 // Allow address constant expressions to be past-the-end pointers. This is
2125 // an extension: the standard requires them to point to an object.
2126 if (!IsReferenceType)
2129 // A reference constant expression must refer to an object.
2131 // FIXME: diagnostic
2136 // Does this refer one past the end of some object?
2137 if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
2138 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
2139 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
2140 << !Designator.Entries.empty() << !!VD << VD;
2141 NoteLValueLocation(Info, Base);
2147 /// Member pointers are constant expressions unless they point to a
2148 /// non-virtual dllimport member function.
2149 static bool CheckMemberPointerConstantExpression(EvalInfo &Info,
2152 const APValue &Value,
2153 Expr::ConstExprUsage Usage) {
2154 const ValueDecl *Member = Value.getMemberPointerDecl();
2155 const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Member);
2158 if (FD->isConsteval()) {
2159 Info.FFDiag(Loc, diag::note_consteval_address_accessible) << /*pointer*/ 0;
2160 Info.Note(FD->getLocation(), diag::note_declared_at);
2163 return Usage == Expr::EvaluateForMangling || FD->isVirtual() ||
2164 !FD->hasAttr<DLLImportAttr>();
2167 /// Check that this core constant expression is of literal type, and if not,
2168 /// produce an appropriate diagnostic.
2169 static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
2170 const LValue *This = nullptr) {
2171 if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx))
2174 // C++1y: A constant initializer for an object o [...] may also invoke
2175 // constexpr constructors for o and its subobjects even if those objects
2176 // are of non-literal class types.
2178 // C++11 missed this detail for aggregates, so classes like this:
2179 // struct foo_t { union { int i; volatile int j; } u; };
2180 // are not (obviously) initializable like so:
2181 // __attribute__((__require_constant_initialization__))
2182 // static const foo_t x = {{0}};
2183 // because "i" is a subobject with non-literal initialization (due to the
2184 // volatile member of the union). See:
2185 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
2186 // Therefore, we use the C++1y behavior.
2187 if (This && Info.EvaluatingDecl == This->getLValueBase())
2190 // Prvalue constant expressions must be of literal types.
2191 if (Info.getLangOpts().CPlusPlus11)
2192 Info.FFDiag(E, diag::note_constexpr_nonliteral)
2195 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2199 static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2200 EvalInfo &Info, SourceLocation DiagLoc,
2201 QualType Type, const APValue &Value,
2202 Expr::ConstExprUsage Usage,
2203 SourceLocation SubobjectLoc,
2204 CheckedTemporaries &CheckedTemps) {
2205 if (!Value.hasValue()) {
2206 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
2208 if (SubobjectLoc.isValid())
2209 Info.Note(SubobjectLoc, diag::note_constexpr_subobject_declared_here);
2213 // We allow _Atomic(T) to be initialized from anything that T can be
2214 // initialized from.
2215 if (const AtomicType *AT = Type->getAs<AtomicType>())
2216 Type = AT->getValueType();
2218 // Core issue 1454: For a literal constant expression of array or class type,
2219 // each subobject of its value shall have been initialized by a constant
2221 if (Value.isArray()) {
2222 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
2223 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
2224 if (!CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
2225 Value.getArrayInitializedElt(I), Usage,
2226 SubobjectLoc, CheckedTemps))
2229 if (!Value.hasArrayFiller())
2231 return CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
2232 Value.getArrayFiller(), Usage, SubobjectLoc,
2235 if (Value.isUnion() && Value.getUnionField()) {
2236 return CheckEvaluationResult(
2237 CERK, Info, DiagLoc, Value.getUnionField()->getType(),
2238 Value.getUnionValue(), Usage, Value.getUnionField()->getLocation(),
2241 if (Value.isStruct()) {
2242 RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
2243 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
2244 unsigned BaseIndex = 0;
2245 for (const CXXBaseSpecifier &BS : CD->bases()) {
2246 if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(),
2247 Value.getStructBase(BaseIndex), Usage,
2248 BS.getBeginLoc(), CheckedTemps))
2253 for (const auto *I : RD->fields()) {
2254 if (I->isUnnamedBitfield())
2257 if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(),
2258 Value.getStructField(I->getFieldIndex()),
2259 Usage, I->getLocation(), CheckedTemps))
2264 if (Value.isLValue() &&
2265 CERK == CheckEvaluationResultKind::ConstantExpression) {
2267 LVal.setFrom(Info.Ctx, Value);
2268 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal, Usage,
2272 if (Value.isMemberPointer() &&
2273 CERK == CheckEvaluationResultKind::ConstantExpression)
2274 return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value, Usage);
2276 // Everything else is fine.
2280 /// Check that this core constant expression value is a valid value for a
2281 /// constant expression. If not, report an appropriate diagnostic. Does not
2282 /// check that the expression is of literal type.
2284 CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc, QualType Type,
2285 const APValue &Value,
2286 Expr::ConstExprUsage Usage = Expr::EvaluateForCodeGen) {
2287 CheckedTemporaries CheckedTemps;
2288 return CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
2289 Info, DiagLoc, Type, Value, Usage,
2290 SourceLocation(), CheckedTemps);
2293 /// Check that this evaluated value is fully-initialized and can be loaded by
2294 /// an lvalue-to-rvalue conversion.
2295 static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc,
2296 QualType Type, const APValue &Value) {
2297 CheckedTemporaries CheckedTemps;
2298 return CheckEvaluationResult(
2299 CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value,
2300 Expr::EvaluateForCodeGen, SourceLocation(), CheckedTemps);
2303 /// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless
2304 /// "the allocated storage is deallocated within the evaluation".
2305 static bool CheckMemoryLeaks(EvalInfo &Info) {
2306 if (!Info.HeapAllocs.empty()) {
2307 // We can still fold to a constant despite a compile-time memory leak,
2308 // so long as the heap allocation isn't referenced in the result (we check
2309 // that in CheckConstantExpression).
2310 Info.CCEDiag(Info.HeapAllocs.begin()->second.AllocExpr,
2311 diag::note_constexpr_memory_leak)
2312 << unsigned(Info.HeapAllocs.size() - 1);
2317 static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
2318 // A null base expression indicates a null pointer. These are always
2319 // evaluatable, and they are false unless the offset is zero.
2320 if (!Value.getLValueBase()) {
2321 Result = !Value.getLValueOffset().isZero();
2325 // We have a non-null base. These are generally known to be true, but if it's
2326 // a weak declaration it can be null at runtime.
2328 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
2329 return !Decl || !Decl->isWeak();
2332 static bool HandleConversionToBool(const APValue &Val, bool &Result) {
2333 switch (Val.getKind()) {
2335 case APValue::Indeterminate:
2338 Result = Val.getInt().getBoolValue();
2340 case APValue::FixedPoint:
2341 Result = Val.getFixedPoint().getBoolValue();
2343 case APValue::Float:
2344 Result = !Val.getFloat().isZero();
2346 case APValue::ComplexInt:
2347 Result = Val.getComplexIntReal().getBoolValue() ||
2348 Val.getComplexIntImag().getBoolValue();
2350 case APValue::ComplexFloat:
2351 Result = !Val.getComplexFloatReal().isZero() ||
2352 !Val.getComplexFloatImag().isZero();
2354 case APValue::LValue:
2355 return EvalPointerValueAsBool(Val, Result);
2356 case APValue::MemberPointer:
2357 Result = Val.getMemberPointerDecl();
2359 case APValue::Vector:
2360 case APValue::Array:
2361 case APValue::Struct:
2362 case APValue::Union:
2363 case APValue::AddrLabelDiff:
2367 llvm_unreachable("unknown APValue kind");
2370 static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
2372 assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition");
2374 if (!Evaluate(Val, Info, E))
2376 return HandleConversionToBool(Val, Result);
2379 template<typename T>
2380 static bool HandleOverflow(EvalInfo &Info, const Expr *E,
2381 const T &SrcValue, QualType DestType) {
2382 Info.CCEDiag(E, diag::note_constexpr_overflow)
2383 << SrcValue << DestType;
2384 return Info.noteUndefinedBehavior();
2387 static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
2388 QualType SrcType, const APFloat &Value,
2389 QualType DestType, APSInt &Result) {
2390 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
2391 // Determine whether we are converting to unsigned or signed.
2392 bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
2394 Result = APSInt(DestWidth, !DestSigned);
2396 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
2397 & APFloat::opInvalidOp)
2398 return HandleOverflow(Info, E, Value, DestType);
2402 static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
2403 QualType SrcType, QualType DestType,
2405 APFloat Value = Result;
2407 Result.convert(Info.Ctx.getFloatTypeSemantics(DestType),
2408 APFloat::rmNearestTiesToEven, &ignored);
2412 static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
2413 QualType DestType, QualType SrcType,
2414 const APSInt &Value) {
2415 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
2416 // Figure out if this is a truncate, extend or noop cast.
2417 // If the input is signed, do a sign extend, noop, or truncate.
2418 APSInt Result = Value.extOrTrunc(DestWidth);
2419 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
2420 if (DestType->isBooleanType())
2421 Result = Value.getBoolValue();
2425 static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
2426 QualType SrcType, const APSInt &Value,
2427 QualType DestType, APFloat &Result) {
2428 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
2429 Result.convertFromAPInt(Value, Value.isSigned(),
2430 APFloat::rmNearestTiesToEven);
2434 static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
2435 APValue &Value, const FieldDecl *FD) {
2436 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield");
2438 if (!Value.isInt()) {
2439 // Trying to store a pointer-cast-to-integer into a bitfield.
2440 // FIXME: In this case, we should provide the diagnostic for casting
2441 // a pointer to an integer.
2442 assert(Value.isLValue() && "integral value neither int nor lvalue?");
2447 APSInt &Int = Value.getInt();
2448 unsigned OldBitWidth = Int.getBitWidth();
2449 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx);
2450 if (NewBitWidth < OldBitWidth)
2451 Int = Int.trunc(NewBitWidth).extend(OldBitWidth);
2455 static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
2458 if (!Evaluate(SVal, Info, E))
2461 Res = SVal.getInt();
2464 if (SVal.isFloat()) {
2465 Res = SVal.getFloat().bitcastToAPInt();
2468 if (SVal.isVector()) {
2469 QualType VecTy = E->getType();
2470 unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
2471 QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
2472 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
2473 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
2474 Res = llvm::APInt::getNullValue(VecSize);
2475 for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
2476 APValue &Elt = SVal.getVectorElt(i);
2477 llvm::APInt EltAsInt;
2479 EltAsInt = Elt.getInt();
2480 } else if (Elt.isFloat()) {
2481 EltAsInt = Elt.getFloat().bitcastToAPInt();
2483 // Don't try to handle vectors of anything other than int or float
2484 // (not sure if it's possible to hit this case).
2485 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2488 unsigned BaseEltSize = EltAsInt.getBitWidth();
2490 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
2492 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
2496 // Give up if the input isn't an int, float, or vector. For example, we
2497 // reject "(v4i16)(intptr_t)&a".
2498 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2502 /// Perform the given integer operation, which is known to need at most BitWidth
2503 /// bits, and check for overflow in the original type (if that type was not an
2505 template<typename Operation>
2506 static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
2507 const APSInt &LHS, const APSInt &RHS,
2508 unsigned BitWidth, Operation Op,
2510 if (LHS.isUnsigned()) {
2511 Result = Op(LHS, RHS);
2515 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
2516 Result = Value.trunc(LHS.getBitWidth());
2517 if (Result.extend(BitWidth) != Value) {
2518 if (Info.checkingForUndefinedBehavior())
2519 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
2520 diag::warn_integer_constant_overflow)
2521 << Result.toString(10) << E->getType();
2523 return HandleOverflow(Info, E, Value, E->getType());
2528 /// Perform the given binary integer operation.
2529 static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS,
2530 BinaryOperatorKind Opcode, APSInt RHS,
2537 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
2538 std::multiplies<APSInt>(), Result);
2540 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2541 std::plus<APSInt>(), Result);
2543 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2544 std::minus<APSInt>(), Result);
2545 case BO_And: Result = LHS & RHS; return true;
2546 case BO_Xor: Result = LHS ^ RHS; return true;
2547 case BO_Or: Result = LHS | RHS; return true;
2551 Info.FFDiag(E, diag::note_expr_divide_by_zero);
2554 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
2555 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
2556 // this operation and gives the two's complement result.
2557 if (RHS.isNegative() && RHS.isAllOnesValue() &&
2558 LHS.isSigned() && LHS.isMinSignedValue())
2559 return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1),
2563 if (Info.getLangOpts().OpenCL)
2564 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2565 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2566 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2568 else if (RHS.isSigned() && RHS.isNegative()) {
2569 // During constant-folding, a negative shift is an opposite shift. Such
2570 // a shift is not a constant expression.
2571 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2576 // C++11 [expr.shift]p1: Shift width must be less than the bit width of
2577 // the shifted type.
2578 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2580 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2581 << RHS << E->getType() << LHS.getBitWidth();
2582 } else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) {
2583 // C++11 [expr.shift]p2: A signed left shift must have a non-negative
2584 // operand, and must not overflow the corresponding unsigned type.
2585 // C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to
2586 // E1 x 2^E2 module 2^N.
2587 if (LHS.isNegative())
2588 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
2589 else if (LHS.countLeadingZeros() < SA)
2590 Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
2596 if (Info.getLangOpts().OpenCL)
2597 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2598 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2599 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2601 else if (RHS.isSigned() && RHS.isNegative()) {
2602 // During constant-folding, a negative shift is an opposite shift. Such a
2603 // shift is not a constant expression.
2604 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2609 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
2611 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2613 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2614 << RHS << E->getType() << LHS.getBitWidth();
2619 case BO_LT: Result = LHS < RHS; return true;
2620 case BO_GT: Result = LHS > RHS; return true;
2621 case BO_LE: Result = LHS <= RHS; return true;
2622 case BO_GE: Result = LHS >= RHS; return true;
2623 case BO_EQ: Result = LHS == RHS; return true;
2624 case BO_NE: Result = LHS != RHS; return true;
2626 llvm_unreachable("BO_Cmp should be handled elsewhere");
2630 /// Perform the given binary floating-point operation, in-place, on LHS.
2631 static bool handleFloatFloatBinOp(EvalInfo &Info, const Expr *E,
2632 APFloat &LHS, BinaryOperatorKind Opcode,
2633 const APFloat &RHS) {
2639 LHS.multiply(RHS, APFloat::rmNearestTiesToEven);
2642 LHS.add(RHS, APFloat::rmNearestTiesToEven);
2645 LHS.subtract(RHS, APFloat::rmNearestTiesToEven);
2649 // If the second operand of / or % is zero the behavior is undefined.
2651 Info.CCEDiag(E, diag::note_expr_divide_by_zero);
2652 LHS.divide(RHS, APFloat::rmNearestTiesToEven);
2657 // If during the evaluation of an expression, the result is not
2658 // mathematically defined [...], the behavior is undefined.
2659 // FIXME: C++ rules require us to not conform to IEEE 754 here.
2661 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
2662 return Info.noteUndefinedBehavior();
2667 static bool handleLogicalOpForVector(const APInt &LHSValue,
2668 BinaryOperatorKind Opcode,
2669 const APInt &RHSValue, APInt &Result) {
2670 bool LHS = (LHSValue != 0);
2671 bool RHS = (RHSValue != 0);
2673 if (Opcode == BO_LAnd)
2674 Result = LHS && RHS;
2676 Result = LHS || RHS;
2679 static bool handleLogicalOpForVector(const APFloat &LHSValue,
2680 BinaryOperatorKind Opcode,
2681 const APFloat &RHSValue, APInt &Result) {
2682 bool LHS = !LHSValue.isZero();
2683 bool RHS = !RHSValue.isZero();
2685 if (Opcode == BO_LAnd)
2686 Result = LHS && RHS;
2688 Result = LHS || RHS;
2692 static bool handleLogicalOpForVector(const APValue &LHSValue,
2693 BinaryOperatorKind Opcode,
2694 const APValue &RHSValue, APInt &Result) {
2695 // The result is always an int type, however operands match the first.
2696 if (LHSValue.getKind() == APValue::Int)
2697 return handleLogicalOpForVector(LHSValue.getInt(), Opcode,
2698 RHSValue.getInt(), Result);
2699 assert(LHSValue.getKind() == APValue::Float && "Should be no other options");
2700 return handleLogicalOpForVector(LHSValue.getFloat(), Opcode,
2701 RHSValue.getFloat(), Result);
2704 template <typename APTy>
2706 handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode,
2707 const APTy &RHSValue, APInt &Result) {
2710 llvm_unreachable("unsupported binary operator");
2712 Result = (LHSValue == RHSValue);
2715 Result = (LHSValue != RHSValue);
2718 Result = (LHSValue < RHSValue);
2721 Result = (LHSValue > RHSValue);
2724 Result = (LHSValue <= RHSValue);
2727 Result = (LHSValue >= RHSValue);
2734 static bool handleCompareOpForVector(const APValue &LHSValue,
2735 BinaryOperatorKind Opcode,
2736 const APValue &RHSValue, APInt &Result) {
2737 // The result is always an int type, however operands match the first.
2738 if (LHSValue.getKind() == APValue::Int)
2739 return handleCompareOpForVectorHelper(LHSValue.getInt(), Opcode,
2740 RHSValue.getInt(), Result);
2741 assert(LHSValue.getKind() == APValue::Float && "Should be no other options");
2742 return handleCompareOpForVectorHelper(LHSValue.getFloat(), Opcode,
2743 RHSValue.getFloat(), Result);
2746 // Perform binary operations for vector types, in place on the LHS.
2747 static bool handleVectorVectorBinOp(EvalInfo &Info, const Expr *E,
2748 BinaryOperatorKind Opcode,
2750 const APValue &RHSValue) {
2751 assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI &&
2752 "Operation not supported on vector types");
2754 const auto *VT = E->getType()->castAs<VectorType>();
2755 unsigned NumElements = VT->getNumElements();
2756 QualType EltTy = VT->getElementType();
2758 // In the cases (typically C as I've observed) where we aren't evaluating
2759 // constexpr but are checking for cases where the LHS isn't yet evaluatable,
2761 if (!LHSValue.isVector()) {
2762 assert(LHSValue.isLValue() &&
2763 "A vector result that isn't a vector OR uncalculated LValue");
2768 assert(LHSValue.getVectorLength() == NumElements &&
2769 RHSValue.getVectorLength() == NumElements && "Different vector sizes");
2771 SmallVector<APValue, 4> ResultElements;
2773 for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) {
2774 APValue LHSElt = LHSValue.getVectorElt(EltNum);
2775 APValue RHSElt = RHSValue.getVectorElt(EltNum);
2777 if (EltTy->isIntegerType()) {
2778 APSInt EltResult{Info.Ctx.getIntWidth(EltTy),
2779 EltTy->isUnsignedIntegerType()};
2780 bool Success = true;
2782 if (BinaryOperator::isLogicalOp(Opcode))
2783 Success = handleLogicalOpForVector(LHSElt, Opcode, RHSElt, EltResult);
2784 else if (BinaryOperator::isComparisonOp(Opcode))
2785 Success = handleCompareOpForVector(LHSElt, Opcode, RHSElt, EltResult);
2787 Success = handleIntIntBinOp(Info, E, LHSElt.getInt(), Opcode,
2788 RHSElt.getInt(), EltResult);
2794 ResultElements.emplace_back(EltResult);
2796 } else if (EltTy->isFloatingType()) {
2797 assert(LHSElt.getKind() == APValue::Float &&
2798 RHSElt.getKind() == APValue::Float &&
2799 "Mismatched LHS/RHS/Result Type");
2800 APFloat LHSFloat = LHSElt.getFloat();
2802 if (!handleFloatFloatBinOp(Info, E, LHSFloat, Opcode,
2803 RHSElt.getFloat())) {
2808 ResultElements.emplace_back(LHSFloat);
2812 LHSValue = APValue(ResultElements.data(), ResultElements.size());
2816 /// Cast an lvalue referring to a base subobject to a derived class, by
2817 /// truncating the lvalue's path to the given length.
2818 static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
2819 const RecordDecl *TruncatedType,
2820 unsigned TruncatedElements) {
2821 SubobjectDesignator &D = Result.Designator;
2823 // Check we actually point to a derived class object.
2824 if (TruncatedElements == D.Entries.size())
2826 assert(TruncatedElements >= D.MostDerivedPathLength &&
2827 "not casting to a derived class");
2828 if (!Result.checkSubobject(Info, E, CSK_Derived))
2831 // Truncate the path to the subobject, and remove any derived-to-base offsets.
2832 const RecordDecl *RD = TruncatedType;
2833 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
2834 if (RD->isInvalidDecl()) return false;
2835 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
2836 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
2837 if (isVirtualBaseClass(D.Entries[I]))
2838 Result.Offset -= Layout.getVBaseClassOffset(Base);
2840 Result.Offset -= Layout.getBaseClassOffset(Base);
2843 D.Entries.resize(TruncatedElements);
2847 static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2848 const CXXRecordDecl *Derived,
2849 const CXXRecordDecl *Base,
2850 const ASTRecordLayout *RL = nullptr) {
2852 if (Derived->isInvalidDecl()) return false;
2853 RL = &Info.Ctx.getASTRecordLayout(Derived);
2856 Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
2857 Obj.addDecl(Info, E, Base, /*Virtual*/ false);
2861 static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2862 const CXXRecordDecl *DerivedDecl,
2863 const CXXBaseSpecifier *Base) {
2864 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
2866 if (!Base->isVirtual())
2867 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
2869 SubobjectDesignator &D = Obj.Designator;
2873 // Extract most-derived object and corresponding type.
2874 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
2875 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
2878 // Find the virtual base class.
2879 if (DerivedDecl->isInvalidDecl()) return false;
2880 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
2881 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
2882 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
2886 static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
2887 QualType Type, LValue &Result) {
2888 for (CastExpr::path_const_iterator PathI = E->path_begin(),
2889 PathE = E->path_end();
2890 PathI != PathE; ++PathI) {
2891 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
2894 Type = (*PathI)->getType();
2899 /// Cast an lvalue referring to a derived class to a known base subobject.
2900 static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result,
2901 const CXXRecordDecl *DerivedRD,
2902 const CXXRecordDecl *BaseRD) {
2903 CXXBasePaths Paths(/*FindAmbiguities=*/false,
2904 /*RecordPaths=*/true, /*DetectVirtual=*/false);
2905 if (!DerivedRD->isDerivedFrom(BaseRD, Paths))
2906 llvm_unreachable("Class must be derived from the passed in base class!");
2908 for (CXXBasePathElement &Elem : Paths.front())
2909 if (!HandleLValueBase(Info, E, Result, Elem.Class, Elem.Base))
2914 /// Update LVal to refer to the given field, which must be a member of the type
2915 /// currently described by LVal.
2916 static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
2917 const FieldDecl *FD,
2918 const ASTRecordLayout *RL = nullptr) {
2920 if (FD->getParent()->isInvalidDecl()) return false;
2921 RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
2924 unsigned I = FD->getFieldIndex();
2925 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)));
2926 LVal.addDecl(Info, E, FD);
2930 /// Update LVal to refer to the given indirect field.
2931 static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
2933 const IndirectFieldDecl *IFD) {
2934 for (const auto *C : IFD->chain())
2935 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C)))
2940 /// Get the size of the given type in char units.
2941 static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
2942 QualType Type, CharUnits &Size) {
2943 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
2945 if (Type->isVoidType() || Type->isFunctionType()) {
2946 Size = CharUnits::One();
2950 if (Type->isDependentType()) {
2955 if (!Type->isConstantSizeType()) {
2956 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
2957 // FIXME: Better diagnostic.
2962 Size = Info.Ctx.getTypeSizeInChars(Type);
2966 /// Update a pointer value to model pointer arithmetic.
2967 /// \param Info - Information about the ongoing evaluation.
2968 /// \param E - The expression being evaluated, for diagnostic purposes.
2969 /// \param LVal - The pointer value to be updated.
2970 /// \param EltTy - The pointee type represented by LVal.
2971 /// \param Adjustment - The adjustment, in objects of type EltTy, to add.
2972 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
2973 LValue &LVal, QualType EltTy,
2974 APSInt Adjustment) {
2975 CharUnits SizeOfPointee;
2976 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
2979 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee);
2983 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
2984 LValue &LVal, QualType EltTy,
2985 int64_t Adjustment) {
2986 return HandleLValueArrayAdjustment(Info, E, LVal, EltTy,
2987 APSInt::get(Adjustment));
2990 /// Update an lvalue to refer to a component of a complex number.
2991 /// \param Info - Information about the ongoing evaluation.
2992 /// \param LVal - The lvalue to be updated.
2993 /// \param EltTy - The complex number's component type.
2994 /// \param Imag - False for the real component, true for the imaginary.
2995 static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
2996 LValue &LVal, QualType EltTy,
2999 CharUnits SizeOfComponent;
3000 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
3002 LVal.Offset += SizeOfComponent;
3004 LVal.addComplex(Info, E, EltTy, Imag);
3008 /// Try to evaluate the initializer for a variable declaration.
3010 /// \param Info Information about the ongoing evaluation.
3011 /// \param E An expression to be used when printing diagnostics.
3012 /// \param VD The variable whose initializer should be obtained.
3013 /// \param Frame The frame in which the variable was created. Must be null
3014 /// if this variable is not local to the evaluation.
3015 /// \param Result Filled in with a pointer to the value of the variable.
3016 static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
3017 const VarDecl *VD, CallStackFrame *Frame,
3018 APValue *&Result, const LValue *LVal) {
3020 // If this is a parameter to an active constexpr function call, perform
3021 // argument substitution.
3022 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) {
3023 // Assume arguments of a potential constant expression are unknown
3024 // constant expressions.
3025 if (Info.checkingPotentialConstantExpression())
3027 if (!Frame || !Frame->Arguments) {
3028 Info.FFDiag(E, diag::note_constexpr_function_param_value_unknown) << VD;
3031 Result = &Frame->Arguments[PVD->getFunctionScopeIndex()];
3035 // If this is a local variable, dig out its value.
3037 Result = LVal ? Frame->getTemporary(VD, LVal->getLValueVersion())
3038 : Frame->getCurrentTemporary(VD);
3040 // Assume variables referenced within a lambda's call operator that were
3041 // not declared within the call operator are captures and during checking
3042 // of a potential constant expression, assume they are unknown constant
3044 assert(isLambdaCallOperator(Frame->Callee) &&
3045 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&
3046 "missing value for local variable");
3047 if (Info.checkingPotentialConstantExpression())
3049 // FIXME: implement capture evaluation during constant expr evaluation.
3050 Info.FFDiag(E->getBeginLoc(),
3051 diag::note_unimplemented_constexpr_lambda_feature_ast)
3052 << "captures not currently allowed";
3058 // Dig out the initializer, and use the declaration which it's attached to.
3059 // FIXME: We should eventually check whether the variable has a reachable
3060 // initializing declaration.
3061 const Expr *Init = VD->getAnyInitializer(VD);
3063 // Don't diagnose during potential constant expression checking; an
3064 // initializer might be added later.
3065 if (!Info.checkingPotentialConstantExpression()) {
3066 Info.FFDiag(E, diag::note_constexpr_var_init_unknown, 1)
3068 Info.Note(VD->getLocation(), diag::note_declared_at);
3073 if (Init->isValueDependent()) {
3074 // The DeclRefExpr is not value-dependent, but the variable it refers to
3075 // has a value-dependent initializer. This should only happen in
3076 // constant-folding cases, where the variable is not actually of a suitable
3077 // type for use in a constant expression (otherwise the DeclRefExpr would
3078 // have been value-dependent too), so diagnose that.
3079 assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx));
3080 if (!Info.checkingPotentialConstantExpression()) {
3081 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
3082 ? diag::note_constexpr_ltor_non_constexpr
3083 : diag::note_constexpr_ltor_non_integral, 1)
3084 << VD << VD->getType();
3085 Info.Note(VD->getLocation(), diag::note_declared_at);
3090 // If we're currently evaluating the initializer of this declaration, use that
3092 if (Info.EvaluatingDecl.dyn_cast<const ValueDecl*>() == VD) {
3093 Result = Info.EvaluatingDeclValue;
3097 // Check that we can fold the initializer. In C++, we will have already done
3098 // this in the cases where it matters for conformance.
3099 SmallVector<PartialDiagnosticAt, 8> Notes;
3100 if (!VD->evaluateValue(Notes)) {
3101 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant,
3102 Notes.size() + 1) << VD;
3103 Info.Note(VD->getLocation(), diag::note_declared_at);
3104 Info.addNotes(Notes);
3108 // Check that the variable is actually usable in constant expressions.
3109 if (!VD->checkInitIsICE()) {
3110 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant,
3111 Notes.size() + 1) << VD;
3112 Info.Note(VD->getLocation(), diag::note_declared_at);
3113 Info.addNotes(Notes);
3116 // Never use the initializer of a weak variable, not even for constant
3117 // folding. We can't be sure that this is the definition that will be used.
3119 Info.FFDiag(E, diag::note_constexpr_var_init_weak) << VD;
3120 Info.Note(VD->getLocation(), diag::note_declared_at);
3124 Result = VD->getEvaluatedValue();
3128 static bool IsConstNonVolatile(QualType T) {
3129 Qualifiers Quals = T.getQualifiers();
3130 return Quals.hasConst() && !Quals.hasVolatile();
3133 /// Get the base index of the given base class within an APValue representing
3134 /// the given derived class.
3135 static unsigned getBaseIndex(const CXXRecordDecl *Derived,
3136 const CXXRecordDecl *Base) {
3137 Base = Base->getCanonicalDecl();
3139 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
3140 E = Derived->bases_end(); I != E; ++I, ++Index) {
3141 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
3145 llvm_unreachable("base class missing from derived class's bases list");
3148 /// Extract the value of a character from a string literal.
3149 static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
3151 assert(!isa<SourceLocExpr>(Lit) &&
3152 "SourceLocExpr should have already been converted to a StringLiteral");
3154 // FIXME: Support MakeStringConstant
3155 if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) {
3157 Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str);
3158 assert(Index <= Str.size() && "Index too large");
3159 return APSInt::getUnsigned(Str.c_str()[Index]);
3162 if (auto PE = dyn_cast<PredefinedExpr>(Lit))
3163 Lit = PE->getFunctionName();
3164 const StringLiteral *S = cast<StringLiteral>(Lit);
3165 const ConstantArrayType *CAT =
3166 Info.Ctx.getAsConstantArrayType(S->getType());
3167 assert(CAT && "string literal isn't an array");
3168 QualType CharType = CAT->getElementType();
3169 assert(CharType->isIntegerType() && "unexpected character type");
3171 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
3172 CharType->isUnsignedIntegerType());
3173 if (Index < S->getLength())
3174 Value = S->getCodeUnit(Index);
3178 // Expand a string literal into an array of characters.
3180 // FIXME: This is inefficient; we should probably introduce something similar
3181 // to the LLVM ConstantDataArray to make this cheaper.
3182 static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S,
3184 QualType AllocType = QualType()) {
3185 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
3186 AllocType.isNull() ? S->getType() : AllocType);
3187 assert(CAT && "string literal isn't an array");
3188 QualType CharType = CAT->getElementType();
3189 assert(CharType->isIntegerType() && "unexpected character type");
3191 unsigned Elts = CAT->getSize().getZExtValue();
3192 Result = APValue(APValue::UninitArray(),
3193 std::min(S->getLength(), Elts), Elts);
3194 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
3195 CharType->isUnsignedIntegerType());
3196 if (Result.hasArrayFiller())
3197 Result.getArrayFiller() = APValue(Value);
3198 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
3199 Value = S->getCodeUnit(I);
3200 Result.getArrayInitializedElt(I) = APValue(Value);
3204 // Expand an array so that it has more than Index filled elements.
3205 static void expandArray(APValue &Array, unsigned Index) {
3206 unsigned Size = Array.getArraySize();
3207 assert(Index < Size);
3209 // Always at least double the number of elements for which we store a value.
3210 unsigned OldElts = Array.getArrayInitializedElts();
3211 unsigned NewElts = std::max(Index+1, OldElts * 2);
3212 NewElts = std::min(Size, std::max(NewElts, 8u));
3214 // Copy the data across.
3215 APValue NewValue(APValue::UninitArray(), NewElts, Size);
3216 for (unsigned I = 0; I != OldElts; ++I)
3217 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I));
3218 for (unsigned I = OldElts; I != NewElts; ++I)
3219 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
3220 if (NewValue.hasArrayFiller())
3221 NewValue.getArrayFiller() = Array.getArrayFiller();
3222 Array.swap(NewValue);
3225 /// Determine whether a type would actually be read by an lvalue-to-rvalue
3226 /// conversion. If it's of class type, we may assume that the copy operation
3227 /// is trivial. Note that this is never true for a union type with fields
3228 /// (because the copy always "reads" the active member) and always true for
3229 /// a non-class type.
3230 static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD);
3231 static bool isReadByLvalueToRvalueConversion(QualType T) {
3232 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3233 return !RD || isReadByLvalueToRvalueConversion(RD);
3235 static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) {
3236 // FIXME: A trivial copy of a union copies the object representation, even if
3237 // the union is empty.
3239 return !RD->field_empty();
3243 for (auto *Field : RD->fields())
3244 if (!Field->isUnnamedBitfield() &&
3245 isReadByLvalueToRvalueConversion(Field->getType()))
3248 for (auto &BaseSpec : RD->bases())
3249 if (isReadByLvalueToRvalueConversion(BaseSpec.getType()))
3255 /// Diagnose an attempt to read from any unreadable field within the specified
3256 /// type, which might be a class type.
3257 static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK,
3259 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3263 if (!RD->hasMutableFields())
3266 for (auto *Field : RD->fields()) {
3267 // If we're actually going to read this field in some way, then it can't
3268 // be mutable. If we're in a union, then assigning to a mutable field
3269 // (even an empty one) can change the active member, so that's not OK.
3270 // FIXME: Add core issue number for the union case.
3271 if (Field->isMutable() &&
3272 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
3273 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) << AK << Field;
3274 Info.Note(Field->getLocation(), diag::note_declared_at);
3278 if (diagnoseMutableFields(Info, E, AK, Field->getType()))
3282 for (auto &BaseSpec : RD->bases())
3283 if (diagnoseMutableFields(Info, E, AK, BaseSpec.getType()))
3286 // All mutable fields were empty, and thus not actually read.
3290 static bool lifetimeStartedInEvaluation(EvalInfo &Info,
3291 APValue::LValueBase Base,
3292 bool MutableSubobject = false) {
3293 // A temporary we created.
3294 if (Base.getCallIndex())
3297 auto *Evaluating = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>();
3301 auto *BaseD = Base.dyn_cast<const ValueDecl*>();
3303 switch (Info.IsEvaluatingDecl) {
3304 case EvalInfo::EvaluatingDeclKind::None:
3307 case EvalInfo::EvaluatingDeclKind::Ctor:
3308 // The variable whose initializer we're evaluating.
3310 return declaresSameEntity(Evaluating, BaseD);
3312 // A temporary lifetime-extended by the variable whose initializer we're
3314 if (auto *BaseE = Base.dyn_cast<const Expr *>())
3315 if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(BaseE))
3316 return declaresSameEntity(BaseMTE->getExtendingDecl(), Evaluating);
3319 case EvalInfo::EvaluatingDeclKind::Dtor:
3320 // C++2a [expr.const]p6:
3321 // [during constant destruction] the lifetime of a and its non-mutable
3322 // subobjects (but not its mutable subobjects) [are] considered to start
3325 // FIXME: We can meaningfully extend this to cover non-const objects, but
3326 // we will need special handling: we should be able to access only
3327 // subobjects of such objects that are themselves declared const.
3329 !(BaseD->getType().isConstQualified() ||
3330 BaseD->getType()->isReferenceType()) ||
3333 return declaresSameEntity(Evaluating, BaseD);
3336 llvm_unreachable("unknown evaluating decl kind");
3340 /// A handle to a complete object (an object that is not a subobject of
3341 /// another object).
3342 struct CompleteObject {
3343 /// The identity of the object.
3344 APValue::LValueBase Base;
3345 /// The value of the complete object.
3347 /// The type of the complete object.
3350 CompleteObject() : Value(nullptr) {}
3351 CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type)
3352 : Base(Base), Value(Value), Type(Type) {}
3354 bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const {
3355 // If this isn't a "real" access (eg, if it's just accessing the type
3356 // info), allow it. We assume the type doesn't change dynamically for
3357 // subobjects of constexpr objects (even though we'd hit UB here if it
3358 // did). FIXME: Is this right?
3359 if (!isAnyAccess(AK))
3362 // In C++14 onwards, it is permitted to read a mutable member whose
3363 // lifetime began within the evaluation.
3364 // FIXME: Should we also allow this in C++11?
3365 if (!Info.getLangOpts().CPlusPlus14)
3367 return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true);
3370 explicit operator bool() const { return !Type.isNull(); }
3372 } // end anonymous namespace
3374 static QualType getSubobjectType(QualType ObjType, QualType SubobjType,
3375 bool IsMutable = false) {
3376 // C++ [basic.type.qualifier]p1:
3377 // - A const object is an object of type const T or a non-mutable subobject
3378 // of a const object.
3379 if (ObjType.isConstQualified() && !IsMutable)
3380 SubobjType.addConst();
3381 // - A volatile object is an object of type const T or a subobject of a
3383 if (ObjType.isVolatileQualified())
3384 SubobjType.addVolatile();
3388 /// Find the designated sub-object of an rvalue.
3389 template<typename SubobjectHandler>
3390 typename SubobjectHandler::result_type
3391 findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
3392 const SubobjectDesignator &Sub, SubobjectHandler &handler) {
3394 // A diagnostic will have already been produced.
3395 return handler.failed();
3396 if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) {
3397 if (Info.getLangOpts().CPlusPlus11)
3398 Info.FFDiag(E, Sub.isOnePastTheEnd()
3399 ? diag::note_constexpr_access_past_end
3400 : diag::note_constexpr_access_unsized_array)
3401 << handler.AccessKind;
3404 return handler.failed();
3407 APValue *O = Obj.Value;
3408 QualType ObjType = Obj.Type;
3409 const FieldDecl *LastField = nullptr;
3410 const FieldDecl *VolatileField = nullptr;
3412 // Walk the designator's path to find the subobject.
3413 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
3414 // Reading an indeterminate value is undefined, but assigning over one is OK.
3415 if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) ||
3416 (O->isIndeterminate() &&
3417 !isValidIndeterminateAccess(handler.AccessKind))) {
3418 if (!Info.checkingPotentialConstantExpression())
3419 Info.FFDiag(E, diag::note_constexpr_access_uninit)
3420 << handler.AccessKind << O->isIndeterminate();
3421 return handler.failed();
3424 // C++ [class.ctor]p5, C++ [class.dtor]p5:
3425 // const and volatile semantics are not applied on an object under
3426 // {con,de}struction.
3427 if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) &&
3428 ObjType->isRecordType() &&
3429 Info.isEvaluatingCtorDtor(
3430 Obj.Base, llvm::makeArrayRef(Sub.Entries.begin(),
3431 Sub.Entries.begin() + I)) !=
3432 ConstructionPhase::None) {
3433 ObjType = Info.Ctx.getCanonicalType(ObjType);
3434 ObjType.removeLocalConst();
3435 ObjType.removeLocalVolatile();
3438 // If this is our last pass, check that the final object type is OK.
3439 if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) {
3440 // Accesses to volatile objects are prohibited.
3441 if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) {
3442 if (Info.getLangOpts().CPlusPlus) {
3445 const NamedDecl *Decl = nullptr;
3446 if (VolatileField) {
3448 Loc = VolatileField->getLocation();
3449 Decl = VolatileField;
3450 } else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) {
3452 Loc = VD->getLocation();
3456 if (auto *E = Obj.Base.dyn_cast<const Expr *>())
3457 Loc = E->getExprLoc();
3459 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
3460 << handler.AccessKind << DiagKind << Decl;
3461 Info.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind;
3463 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
3465 return handler.failed();
3468 // If we are reading an object of class type, there may still be more
3469 // things we need to check: if there are any mutable subobjects, we
3470 // cannot perform this read. (This only happens when performing a trivial
3471 // copy or assignment.)
3472 if (ObjType->isRecordType() &&
3473 !Obj.mayAccessMutableMembers(Info, handler.AccessKind) &&
3474 diagnoseMutableFields(Info, E, handler.AccessKind, ObjType))
3475 return handler.failed();
3479 if (!handler.found(*O, ObjType))
3482 // If we modified a bit-field, truncate it to the right width.
3483 if (isModification(handler.AccessKind) &&
3484 LastField && LastField->isBitField() &&
3485 !truncateBitfieldValue(Info, E, *O, LastField))
3491 LastField = nullptr;
3492 if (ObjType->isArrayType()) {
3493 // Next subobject is an array element.
3494 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
3495 assert(CAT && "vla in literal type?");
3496 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
3497 if (CAT->getSize().ule(Index)) {
3498 // Note, it should not be possible to form a pointer with a valid
3499 // designator which points more than one past the end of the array.
3500 if (Info.getLangOpts().CPlusPlus11)
3501 Info.FFDiag(E, diag::note_constexpr_access_past_end)
3502 << handler.AccessKind;
3505 return handler.failed();
3508 ObjType = CAT->getElementType();
3510 if (O->getArrayInitializedElts() > Index)
3511 O = &O->getArrayInitializedElt(Index);
3512 else if (!isRead(handler.AccessKind)) {
3513 expandArray(*O, Index);
3514 O = &O->getArrayInitializedElt(Index);
3516 O = &O->getArrayFiller();
3517 } else if (ObjType->isAnyComplexType()) {
3518 // Next subobject is a complex number.
3519 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
3521 if (Info.getLangOpts().CPlusPlus11)
3522 Info.FFDiag(E, diag::note_constexpr_access_past_end)
3523 << handler.AccessKind;
3526 return handler.failed();
3529 ObjType = getSubobjectType(
3530 ObjType, ObjType->castAs<ComplexType>()->getElementType());
3532 assert(I == N - 1 && "extracting subobject of scalar?");
3533 if (O->isComplexInt()) {
3534 return handler.found(Index ? O->getComplexIntImag()
3535 : O->getComplexIntReal(), ObjType);
3537 assert(O->isComplexFloat());
3538 return handler.found(Index ? O->getComplexFloatImag()
3539 : O->getComplexFloatReal(), ObjType);
3541 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
3542 if (Field->isMutable() &&
3543 !Obj.mayAccessMutableMembers(Info, handler.AccessKind)) {
3544 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1)
3545 << handler.AccessKind << Field;
3546 Info.Note(Field->getLocation(), diag::note_declared_at);
3547 return handler.failed();
3550 // Next subobject is a class, struct or union field.
3551 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
3552 if (RD->isUnion()) {
3553 const FieldDecl *UnionField = O->getUnionField();
3555 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
3556 if (I == N - 1 && handler.AccessKind == AK_Construct) {
3557 // Placement new onto an inactive union member makes it active.
3558 O->setUnion(Field, APValue());
3560 // FIXME: If O->getUnionValue() is absent, report that there's no
3561 // active union member rather than reporting the prior active union
3562 // member. We'll need to fix nullptr_t to not use APValue() as its
3563 // representation first.
3564 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
3565 << handler.AccessKind << Field << !UnionField << UnionField;
3566 return handler.failed();
3569 O = &O->getUnionValue();
3571 O = &O->getStructField(Field->getFieldIndex());
3573 ObjType = getSubobjectType(ObjType, Field->getType(), Field->isMutable());
3575 if (Field->getType().isVolatileQualified())
3576 VolatileField = Field;
3578 // Next subobject is a base class.
3579 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
3580 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
3581 O = &O->getStructBase(getBaseIndex(Derived, Base));
3583 ObjType = getSubobjectType(ObjType, Info.Ctx.getRecordType(Base));
3589 struct ExtractSubobjectHandler {
3593 const AccessKinds AccessKind;
3595 typedef bool result_type;
3596 bool failed() { return false; }
3597 bool found(APValue &Subobj, QualType SubobjType) {
3599 if (AccessKind == AK_ReadObjectRepresentation)
3601 return CheckFullyInitialized(Info, E->getExprLoc(), SubobjType, Result);
3603 bool found(APSInt &Value, QualType SubobjType) {
3604 Result = APValue(Value);
3607 bool found(APFloat &Value, QualType SubobjType) {
3608 Result = APValue(Value);
3612 } // end anonymous namespace
3614 /// Extract the designated sub-object of an rvalue.
3615 static bool extractSubobject(EvalInfo &Info, const Expr *E,
3616 const CompleteObject &Obj,
3617 const SubobjectDesignator &Sub, APValue &Result,
3618 AccessKinds AK = AK_Read) {
3619 assert(AK == AK_Read || AK == AK_ReadObjectRepresentation);
3620 ExtractSubobjectHandler Handler = {Info, E, Result, AK};
3621 return findSubobject(Info, E, Obj, Sub, Handler);
3625 struct ModifySubobjectHandler {
3630 typedef bool result_type;
3631 static const AccessKinds AccessKind = AK_Assign;
3633 bool checkConst(QualType QT) {
3634 // Assigning to a const object has undefined behavior.
3635 if (QT.isConstQualified()) {
3636 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3642 bool failed() { return false; }
3643 bool found(APValue &Subobj, QualType SubobjType) {
3644 if (!checkConst(SubobjType))
3646 // We've been given ownership of NewVal, so just swap it in.
3647 Subobj.swap(NewVal);
3650 bool found(APSInt &Value, QualType SubobjType) {
3651 if (!checkConst(SubobjType))
3653 if (!NewVal.isInt()) {
3654 // Maybe trying to write a cast pointer value into a complex?
3658 Value = NewVal.getInt();
3661 bool found(APFloat &Value, QualType SubobjType) {
3662 if (!checkConst(SubobjType))
3664 Value = NewVal.getFloat();
3668 } // end anonymous namespace
3670 const AccessKinds ModifySubobjectHandler::AccessKind;
3672 /// Update the designated sub-object of an rvalue to the given value.
3673 static bool modifySubobject(EvalInfo &Info, const Expr *E,
3674 const CompleteObject &Obj,
3675 const SubobjectDesignator &Sub,
3677 ModifySubobjectHandler Handler = { Info, NewVal, E };
3678 return findSubobject(Info, E, Obj, Sub, Handler);
3681 /// Find the position where two subobject designators diverge, or equivalently
3682 /// the length of the common initial subsequence.
3683 static unsigned FindDesignatorMismatch(QualType ObjType,
3684 const SubobjectDesignator &A,
3685 const SubobjectDesignator &B,
3686 bool &WasArrayIndex) {
3687 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
3688 for (/**/; I != N; ++I) {
3689 if (!ObjType.isNull() &&
3690 (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
3691 // Next subobject is an array element.
3692 if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) {
3693 WasArrayIndex = true;
3696 if (ObjType->isAnyComplexType())
3697 ObjType = ObjType->castAs<ComplexType>()->getElementType();
3699 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
3701 if (A.Entries[I].getAsBaseOrMember() !=
3702 B.Entries[I].getAsBaseOrMember()) {
3703 WasArrayIndex = false;
3706 if (const FieldDecl *FD = getAsField(A.Entries[I]))
3707 // Next subobject is a field.
3708 ObjType = FD->getType();
3710 // Next subobject is a base class.
3711 ObjType = QualType();
3714 WasArrayIndex = false;
3718 /// Determine whether the given subobject designators refer to elements of the
3719 /// same array object.
3720 static bool AreElementsOfSameArray(QualType ObjType,
3721 const SubobjectDesignator &A,
3722 const SubobjectDesignator &B) {
3723 if (A.Entries.size() != B.Entries.size())
3726 bool IsArray = A.MostDerivedIsArrayElement;
3727 if (IsArray && A.MostDerivedPathLength != A.Entries.size())
3728 // A is a subobject of the array element.
3731 // If A (and B) designates an array element, the last entry will be the array
3732 // index. That doesn't have to match. Otherwise, we're in the 'implicit array
3733 // of length 1' case, and the entire path must match.
3735 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
3736 return CommonLength >= A.Entries.size() - IsArray;
3739 /// Find the complete object to which an LValue refers.
3740 static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
3741 AccessKinds AK, const LValue &LVal,
3742 QualType LValType) {
3743 if (LVal.InvalidBase) {
3745 return CompleteObject();
3749 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
3750 return CompleteObject();
3753 CallStackFrame *Frame = nullptr;
3755 if (LVal.getLValueCallIndex()) {
3756 std::tie(Frame, Depth) =
3757 Info.getCallFrameAndDepth(LVal.getLValueCallIndex());
3759 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
3760 << AK << LVal.Base.is<const ValueDecl*>();
3761 NoteLValueLocation(Info, LVal.Base);
3762 return CompleteObject();
3766 bool IsAccess = isAnyAccess(AK);
3768 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
3769 // is not a constant expression (even if the object is non-volatile). We also
3770 // apply this rule to C++98, in order to conform to the expected 'volatile'
3772 if (isFormalAccess(AK) && LValType.isVolatileQualified()) {
3773 if (Info.getLangOpts().CPlusPlus)
3774 Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
3778 return CompleteObject();
3781 // Compute value storage location and type of base object.
3782 APValue *BaseVal = nullptr;
3783 QualType BaseType = getType(LVal.Base);
3785 if (const ConstantExpr *CE =
3786 dyn_cast_or_null<ConstantExpr>(LVal.Base.dyn_cast<const Expr *>())) {
3787 /// Nested immediate invocation have been previously removed so if we found
3788 /// a ConstantExpr it can only be the EvaluatingDecl.
3789 assert(CE->isImmediateInvocation() && CE == Info.EvaluatingDecl);
3791 BaseVal = Info.EvaluatingDeclValue;
3792 } else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) {
3793 // Allow reading from a GUID declaration.
3794 if (auto *GD = dyn_cast<MSGuidDecl>(D)) {
3795 if (isModification(AK)) {
3796 // All the remaining cases do not permit modification of the object.
3797 Info.FFDiag(E, diag::note_constexpr_modify_global);
3798 return CompleteObject();
3800 APValue &V = GD->getAsAPValue();
3802 Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
3804 return CompleteObject();
3806 return CompleteObject(LVal.Base, &V, GD->getType());
3809 // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
3810 // In C++11, constexpr, non-volatile variables initialized with constant
3811 // expressions are constant expressions too. Inside constexpr functions,
3812 // parameters are constant expressions even if they're non-const.
3813 // In C++1y, objects local to a constant expression (those with a Frame) are
3814 // both readable and writable inside constant expressions.
3815 // In C, such things can also be folded, although they are not ICEs.
3816 const VarDecl *VD = dyn_cast<VarDecl>(D);
3818 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
3821 if (!VD || VD->isInvalidDecl()) {
3823 return CompleteObject();
3826 // In OpenCL if a variable is in constant address space it is a const value.
3827 bool IsConstant = BaseType.isConstQualified() ||
3828 (Info.getLangOpts().OpenCL &&
3829 BaseType.getAddressSpace() == LangAS::opencl_constant);
3831 // Unless we're looking at a local variable or argument in a constexpr call,
3832 // the variable we're reading must be const.
3834 if (Info.getLangOpts().CPlusPlus14 &&
3835 lifetimeStartedInEvaluation(Info, LVal.Base)) {
3836 // OK, we can read and modify an object if we're in the process of
3837 // evaluating its initializer, because its lifetime began in this
3839 } else if (isModification(AK)) {
3840 // All the remaining cases do not permit modification of the object.
3841 Info.FFDiag(E, diag::note_constexpr_modify_global);
3842 return CompleteObject();
3843 } else if (VD->isConstexpr()) {
3844 // OK, we can read this variable.
3845 } else if (BaseType->isIntegralOrEnumerationType()) {
3846 // In OpenCL if a variable is in constant address space it is a const
3850 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
3851 if (Info.getLangOpts().CPlusPlus) {
3852 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
3853 Info.Note(VD->getLocation(), diag::note_declared_at);
3857 return CompleteObject();
3859 } else if (!IsAccess) {
3860 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
3861 } else if (IsConstant && Info.checkingPotentialConstantExpression() &&
3862 BaseType->isLiteralType(Info.Ctx) && !VD->hasDefinition()) {
3863 // This variable might end up being constexpr. Don't diagnose it yet.
3864 } else if (IsConstant) {
3865 // Keep evaluating to see what we can do. In particular, we support
3866 // folding of const floating-point types, in order to make static const
3867 // data members of such types (supported as an extension) more useful.
3868 if (Info.getLangOpts().CPlusPlus) {
3869 Info.CCEDiag(E, Info.getLangOpts().CPlusPlus11
3870 ? diag::note_constexpr_ltor_non_constexpr
3871 : diag::note_constexpr_ltor_non_integral, 1)
3873 Info.Note(VD->getLocation(), diag::note_declared_at);
3878 // Never allow reading a non-const value.
3879 if (Info.getLangOpts().CPlusPlus) {
3880 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
3881 ? diag::note_constexpr_ltor_non_constexpr
3882 : diag::note_constexpr_ltor_non_integral, 1)
3884 Info.Note(VD->getLocation(), diag::note_declared_at);
3888 return CompleteObject();
3892 if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal, &LVal))
3893 return CompleteObject();
3894 } else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) {
3895 Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA);
3897 Info.FFDiag(E, diag::note_constexpr_access_deleted_object) << AK;
3898 return CompleteObject();
3900 return CompleteObject(LVal.Base, &(*Alloc)->Value,
3901 LVal.Base.getDynamicAllocType());
3903 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
3906 if (const MaterializeTemporaryExpr *MTE =
3907 dyn_cast_or_null<MaterializeTemporaryExpr>(Base)) {
3908 assert(MTE->getStorageDuration() == SD_Static &&
3909 "should have a frame for a non-global materialized temporary");
3911 // Per C++1y [expr.const]p2:
3912 // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
3913 // - a [...] glvalue of integral or enumeration type that refers to
3914 // a non-volatile const object [...]
3916 // - a [...] glvalue of literal type that refers to a non-volatile
3917 // object whose lifetime began within the evaluation of e.
3919 // C++11 misses the 'began within the evaluation of e' check and
3920 // instead allows all temporaries, including things like:
3923 // constexpr int k = r;
3924 // Therefore we use the C++14 rules in C++11 too.
3926 // Note that temporaries whose lifetimes began while evaluating a
3927 // variable's constructor are not usable while evaluating the
3928 // corresponding destructor, not even if they're of const-qualified
3930 if (!(BaseType.isConstQualified() &&
3931 BaseType->isIntegralOrEnumerationType()) &&
3932 !lifetimeStartedInEvaluation(Info, LVal.Base)) {
3934 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
3935 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
3936 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
3937 return CompleteObject();
3940 BaseVal = MTE->getOrCreateValue(false);
3941 assert(BaseVal && "got reference to unevaluated temporary");
3944 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
3947 Info.FFDiag(E, diag::note_constexpr_access_unreadable_object)
3949 << Val.getAsString(Info.Ctx,
3950 Info.Ctx.getLValueReferenceType(LValType));
3951 NoteLValueLocation(Info, LVal.Base);
3952 return CompleteObject();
3955 BaseVal = Frame->getTemporary(Base, LVal.Base.getVersion());
3956 assert(BaseVal && "missing value for temporary");
3960 // In C++14, we can't safely access any mutable state when we might be
3961 // evaluating after an unmodeled side effect.
3963 // FIXME: Not all local state is mutable. Allow local constant subobjects
3964 // to be read here (but take care with 'mutable' fields).
3965 if ((Frame && Info.getLangOpts().CPlusPlus14 &&
3966 Info.EvalStatus.HasSideEffects) ||
3967 (isModification(AK) && Depth < Info.SpeculativeEvaluationDepth))
3968 return CompleteObject();
3970 return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType);
3973 /// Perform an lvalue-to-rvalue conversion on the given glvalue. This
3974 /// can also be used for 'lvalue-to-lvalue' conversions for looking up the
3975 /// glvalue referred to by an entity of reference type.
3977 /// \param Info - Information about the ongoing evaluation.
3978 /// \param Conv - The expression for which we are performing the conversion.
3979 /// Used for diagnostics.
3980 /// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
3981 /// case of a non-class type).
3982 /// \param LVal - The glvalue on which we are attempting to perform this action.
3983 /// \param RVal - The produced value will be placed here.
3984 /// \param WantObjectRepresentation - If true, we're looking for the object
3985 /// representation rather than the value, and in particular,
3986 /// there is no requirement that the result be fully initialized.
3988 handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type,
3989 const LValue &LVal, APValue &RVal,
3990 bool WantObjectRepresentation = false) {
3991 if (LVal.Designator.Invalid)
3994 // Check for special cases where there is no existing APValue to look at.
3995 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
3998 WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read;
4000 if (Base && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) {
4001 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) {
4002 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
4003 // initializer until now for such expressions. Such an expression can't be
4004 // an ICE in C, so this only matters for fold.
4005 if (Type.isVolatileQualified()) {
4010 if (!Evaluate(Lit, Info, CLE->getInitializer()))
4012 CompleteObject LitObj(LVal.Base, &Lit, Base->getType());
4013 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal, AK);
4014 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) {
4015 // Special-case character extraction so we don't have to construct an
4016 // APValue for the whole string.
4017 assert(LVal.Designator.Entries.size() <= 1 &&
4018 "Can only read characters from string literals");
4019 if (LVal.Designator.Entries.empty()) {
4020 // Fail for now for LValue to RValue conversion of an array.
4021 // (This shouldn't show up in C/C++, but it could be triggered by a
4022 // weird EvaluateAsRValue call from a tool.)
4026 if (LVal.Designator.isOnePastTheEnd()) {
4027 if (Info.getLangOpts().CPlusPlus11)
4028 Info.FFDiag(Conv, diag::note_constexpr_access_past_end) << AK;
4033 uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex();
4034 RVal = APValue(extractStringLiteralCharacter(Info, Base, CharIndex));
4039 CompleteObject Obj = findCompleteObject(Info, Conv, AK, LVal, Type);
4040 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal, AK);
4043 /// Perform an assignment of Val to LVal. Takes ownership of Val.
4044 static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
4045 QualType LValType, APValue &Val) {
4046 if (LVal.Designator.Invalid)
4049 if (!Info.getLangOpts().CPlusPlus14) {
4054 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
4055 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
4059 struct CompoundAssignSubobjectHandler {
4062 QualType PromotedLHSType;
4063 BinaryOperatorKind Opcode;
4066 static const AccessKinds AccessKind = AK_Assign;
4068 typedef bool result_type;
4070 bool checkConst(QualType QT) {
4071 // Assigning to a const object has undefined behavior.
4072 if (QT.isConstQualified()) {
4073 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
4079 bool failed() { return false; }
4080 bool found(APValue &Subobj, QualType SubobjType) {
4081 switch (Subobj.getKind()) {
4083 return found(Subobj.getInt(), SubobjType);
4084 case APValue::Float:
4085 return found(Subobj.getFloat(), SubobjType);
4086 case APValue::ComplexInt:
4087 case APValue::ComplexFloat:
4088 // FIXME: Implement complex compound assignment.
4091 case APValue::LValue:
4092 return foundPointer(Subobj, SubobjType);
4093 case APValue::Vector:
4094 return foundVector(Subobj, SubobjType);
4096 // FIXME: can this happen?
4102 bool foundVector(APValue &Value, QualType SubobjType) {
4103 if (!checkConst(SubobjType))
4106 if (!SubobjType->isVectorType()) {
4110 return handleVectorVectorBinOp(Info, E, Opcode, Value, RHS);
4113 bool found(APSInt &Value, QualType SubobjType) {
4114 if (!checkConst(SubobjType))
4117 if (!SubobjType->isIntegerType()) {
4118 // We don't support compound assignment on integer-cast-to-pointer
4126 HandleIntToIntCast(Info, E, PromotedLHSType, SubobjType, Value);
4127 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
4129 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
4131 } else if (RHS.isFloat()) {
4132 APFloat FValue(0.0);
4133 return HandleIntToFloatCast(Info, E, SubobjType, Value, PromotedLHSType,
4135 handleFloatFloatBinOp(Info, E, FValue, Opcode, RHS.getFloat()) &&
4136 HandleFloatToIntCast(Info, E, PromotedLHSType, FValue, SubobjType,
4143 bool found(APFloat &Value, QualType SubobjType) {
4144 return checkConst(SubobjType) &&
4145 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
4147 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
4148 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
4150 bool foundPointer(APValue &Subobj, QualType SubobjType) {
4151 if (!checkConst(SubobjType))
4154 QualType PointeeType;
4155 if (const PointerType *PT = SubobjType->getAs<PointerType>())
4156 PointeeType = PT->getPointeeType();
4158 if (PointeeType.isNull() || !RHS.isInt() ||
4159 (Opcode != BO_Add && Opcode != BO_Sub)) {
4164 APSInt Offset = RHS.getInt();
4165 if (Opcode == BO_Sub)
4166 negateAsSigned(Offset);
4169 LVal.setFrom(Info.Ctx, Subobj);
4170 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
4172 LVal.moveInto(Subobj);
4176 } // end anonymous namespace
4178 const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
4180 /// Perform a compound assignment of LVal <op>= RVal.
4181 static bool handleCompoundAssignment(
4182 EvalInfo &Info, const Expr *E,
4183 const LValue &LVal, QualType LValType, QualType PromotedLValType,
4184 BinaryOperatorKind Opcode, const APValue &RVal) {
4185 if (LVal.Designator.Invalid)
4188 if (!Info.getLangOpts().CPlusPlus14) {
4193 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
4194 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
4196 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4200 struct IncDecSubobjectHandler {
4202 const UnaryOperator *E;
4203 AccessKinds AccessKind;
4206 typedef bool result_type;
4208 bool checkConst(QualType QT) {
4209 // Assigning to a const object has undefined behavior.
4210 if (QT.isConstQualified()) {
4211 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
4217 bool failed() { return false; }
4218 bool found(APValue &Subobj, QualType SubobjType) {
4219 // Stash the old value. Also clear Old, so we don't clobber it later
4220 // if we're post-incrementing a complex.
4226 switch (Subobj.getKind()) {
4228 return found(Subobj.getInt(), SubobjType);
4229 case APValue::Float:
4230 return found(Subobj.getFloat(), SubobjType);
4231 case APValue::ComplexInt:
4232 return found(Subobj.getComplexIntReal(),
4233 SubobjType->castAs<ComplexType>()->getElementType()
4234 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
4235 case APValue::ComplexFloat:
4236 return found(Subobj.getComplexFloatReal(),
4237 SubobjType->castAs<ComplexType>()->getElementType()
4238 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
4239 case APValue::LValue:
4240 return foundPointer(Subobj, SubobjType);
4242 // FIXME: can this happen?
4247 bool found(APSInt &Value, QualType SubobjType) {
4248 if (!checkConst(SubobjType))
4251 if (!SubobjType->isIntegerType()) {
4252 // We don't support increment / decrement on integer-cast-to-pointer
4258 if (Old) *Old = APValue(Value);
4260 // bool arithmetic promotes to int, and the conversion back to bool
4261 // doesn't reduce mod 2^n, so special-case it.
4262 if (SubobjType->isBooleanType()) {
4263 if (AccessKind == AK_Increment)
4270 bool WasNegative = Value.isNegative();
4271 if (AccessKind == AK_Increment) {
4274 if (!WasNegative && Value.isNegative() && E->canOverflow()) {
4275 APSInt ActualValue(Value, /*IsUnsigned*/true);
4276 return HandleOverflow(Info, E, ActualValue, SubobjType);
4281 if (WasNegative && !Value.isNegative() && E->canOverflow()) {
4282 unsigned BitWidth = Value.getBitWidth();
4283 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
4284 ActualValue.setBit(BitWidth);
4285 return HandleOverflow(Info, E, ActualValue, SubobjType);
4290 bool found(APFloat &Value, QualType SubobjType) {
4291 if (!checkConst(SubobjType))
4294 if (Old) *Old = APValue(Value);
4296 APFloat One(Value.getSemantics(), 1);
4297 if (AccessKind == AK_Increment)
4298 Value.add(One, APFloat::rmNearestTiesToEven);
4300 Value.subtract(One, APFloat::rmNearestTiesToEven);
4303 bool foundPointer(APValue &Subobj, QualType SubobjType) {
4304 if (!checkConst(SubobjType))
4307 QualType PointeeType;
4308 if (const PointerType *PT = SubobjType->getAs<PointerType>())
4309 PointeeType = PT->getPointeeType();
4316 LVal.setFrom(Info.Ctx, Subobj);
4317 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
4318 AccessKind == AK_Increment ? 1 : -1))
4320 LVal.moveInto(Subobj);
4324 } // end anonymous namespace
4326 /// Perform an increment or decrement on LVal.
4327 static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
4328 QualType LValType, bool IsIncrement, APValue *Old) {
4329 if (LVal.Designator.Invalid)
4332 if (!Info.getLangOpts().CPlusPlus14) {
4337 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
4338 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
4339 IncDecSubobjectHandler Handler = {Info, cast<UnaryOperator>(E), AK, Old};
4340 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4343 /// Build an lvalue for the object argument of a member function call.
4344 static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
4346 if (Object->getType()->isPointerType() && Object->isRValue())
4347 return EvaluatePointer(Object, This, Info);
4349 if (Object->isGLValue())
4350 return EvaluateLValue(Object, This, Info);
4352 if (Object->getType()->isLiteralType(Info.Ctx))
4353 return EvaluateTemporary(Object, This, Info);
4355 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
4359 /// HandleMemberPointerAccess - Evaluate a member access operation and build an
4360 /// lvalue referring to the result.
4362 /// \param Info - Information about the ongoing evaluation.
4363 /// \param LV - An lvalue referring to the base of the member pointer.
4364 /// \param RHS - The member pointer expression.
4365 /// \param IncludeMember - Specifies whether the member itself is included in
4366 /// the resulting LValue subobject designator. This is not possible when
4367 /// creating a bound member function.
4368 /// \return The field or method declaration to which the member pointer refers,
4369 /// or 0 if evaluation fails.
4370 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
4374 bool IncludeMember = true) {
4376 if (!EvaluateMemberPointer(RHS, MemPtr, Info))
4379 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
4380 // member value, the behavior is undefined.
4381 if (!MemPtr.getDecl()) {
4382 // FIXME: Specific diagnostic.
4387 if (MemPtr.isDerivedMember()) {
4388 // This is a member of some derived class. Truncate LV appropriately.
4389 // The end of the derived-to-base path for the base object must match the
4390 // derived-to-base path for the member pointer.
4391 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
4392 LV.Designator.Entries.size()) {
4396 unsigned PathLengthToMember =
4397 LV.Designator.Entries.size() - MemPtr.Path.size();
4398 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
4399 const CXXRecordDecl *LVDecl = getAsBaseClass(
4400 LV.Designator.Entries[PathLengthToMember + I]);
4401 const CXXRecordDecl *MPDecl = MemPtr.Path[I];
4402 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
4408 // Truncate the lvalue to the appropriate derived class.
4409 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
4410 PathLengthToMember))
4412 } else if (!MemPtr.Path.empty()) {
4413 // Extend the LValue path with the member pointer's path.
4414 LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
4415 MemPtr.Path.size() + IncludeMember);
4417 // Walk down to the appropriate base class.
4418 if (const PointerType *PT = LVType->getAs<PointerType>())
4419 LVType = PT->getPointeeType();
4420 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
4421 assert(RD && "member pointer access on non-class-type expression");
4422 // The first class in the path is that of the lvalue.
4423 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
4424 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
4425 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base))
4429 // Finally cast to the class containing the member.
4430 if (!HandleLValueDirectBase(Info, RHS, LV, RD,
4431 MemPtr.getContainingRecord()))
4435 // Add the member. Note that we cannot build bound member functions here.
4436 if (IncludeMember) {
4437 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) {
4438 if (!HandleLValueMember(Info, RHS, LV, FD))
4440 } else if (const IndirectFieldDecl *IFD =
4441 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) {
4442 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD))
4445 llvm_unreachable("can't construct reference to bound member function");
4449 return MemPtr.getDecl();
4452 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
4453 const BinaryOperator *BO,
4455 bool IncludeMember = true) {
4456 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI);
4458 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) {
4459 if (Info.noteFailure()) {
4461 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info);
4466 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV,
4467 BO->getRHS(), IncludeMember);
4470 /// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
4471 /// the provided lvalue, which currently refers to the base object.
4472 static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
4474 SubobjectDesignator &D = Result.Designator;
4475 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
4478 QualType TargetQT = E->getType();
4479 if (const PointerType *PT = TargetQT->getAs<PointerType>())
4480 TargetQT = PT->getPointeeType();
4482 // Check this cast lands within the final derived-to-base subobject path.
4483 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
4484 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
4485 << D.MostDerivedType << TargetQT;
4489 // Check the type of the final cast. We don't need to check the path,
4490 // since a cast can only be formed if the path is unique.
4491 unsigned NewEntriesSize = D.Entries.size() - E->path_size();
4492 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
4493 const CXXRecordDecl *FinalType;
4494 if (NewEntriesSize == D.MostDerivedPathLength)
4495 FinalType = D.MostDerivedType->getAsCXXRecordDecl();
4497 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
4498 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
4499 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
4500 << D.MostDerivedType << TargetQT;
4504 // Truncate the lvalue to the appropriate derived class.
4505 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
4508 /// Get the value to use for a default-initialized object of type T.
4509 /// Return false if it encounters something invalid.
4510 static bool getDefaultInitValue(QualType T, APValue &Result) {
4511 bool Success = true;
4512 if (auto *RD = T->getAsCXXRecordDecl()) {
4513 if (RD->isInvalidDecl()) {
4517 if (RD->isUnion()) {
4518 Result = APValue((const FieldDecl *)nullptr);
4521 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
4522 std::distance(RD->field_begin(), RD->field_end()));
4525 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
4526 End = RD->bases_end();
4527 I != End; ++I, ++Index)
4528 Success &= getDefaultInitValue(I->getType(), Result.getStructBase(Index));
4530 for (const auto *I : RD->fields()) {
4531 if (I->isUnnamedBitfield())
4533 Success &= getDefaultInitValue(I->getType(),
4534 Result.getStructField(I->getFieldIndex()));
4540 dyn_cast_or_null<ConstantArrayType>(T->getAsArrayTypeUnsafe())) {
4541 Result = APValue(APValue::UninitArray(), 0, AT->getSize().getZExtValue());
4542 if (Result.hasArrayFiller())
4544 getDefaultInitValue(AT->getElementType(), Result.getArrayFiller());
4549 Result = APValue::IndeterminateValue();
4554 enum EvalStmtResult {
4555 /// Evaluation failed.
4557 /// Hit a 'return' statement.
4559 /// Evaluation succeeded.
4561 /// Hit a 'continue' statement.
4563 /// Hit a 'break' statement.
4565 /// Still scanning for 'case' or 'default' statement.
4570 static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
4571 // We don't need to evaluate the initializer for a static local.
4572 if (!VD->hasLocalStorage())
4577 Info.CurrentCall->createTemporary(VD, VD->getType(), true, Result);
4579 const Expr *InitE = VD->getInit();
4581 return getDefaultInitValue(VD->getType(), Val);
4583 if (InitE->isValueDependent())
4586 if (!EvaluateInPlace(Val, Info, Result, InitE)) {
4587 // Wipe out any partially-computed value, to allow tracking that this
4588 // evaluation failed.
4596 static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
4599 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
4600 OK &= EvaluateVarDecl(Info, VD);
4602 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D))
4603 for (auto *BD : DD->bindings())
4604 if (auto *VD = BD->getHoldingVar())
4605 OK &= EvaluateDecl(Info, VD);
4611 /// Evaluate a condition (either a variable declaration or an expression).
4612 static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
4613 const Expr *Cond, bool &Result) {
4614 FullExpressionRAII Scope(Info);
4615 if (CondDecl && !EvaluateDecl(Info, CondDecl))
4617 if (!EvaluateAsBooleanCondition(Cond, Result, Info))
4619 return Scope.destroy();
4623 /// A location where the result (returned value) of evaluating a
4624 /// statement should be stored.
4626 /// The APValue that should be filled in with the returned value.
4628 /// The location containing the result, if any (used to support RVO).
4632 struct TempVersionRAII {
4633 CallStackFrame &Frame;
4635 TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) {
4636 Frame.pushTempVersion();
4639 ~TempVersionRAII() {
4640 Frame.popTempVersion();
4646 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
4648 const SwitchCase *SC = nullptr);
4650 /// Evaluate the body of a loop, and translate the result as appropriate.
4651 static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
4653 const SwitchCase *Case = nullptr) {
4654 BlockScopeRAII Scope(Info);
4656 EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case);
4657 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
4662 return ESR_Succeeded;
4665 return ESR_Continue;
4668 case ESR_CaseNotFound:
4671 llvm_unreachable("Invalid EvalStmtResult!");
4674 /// Evaluate a switch statement.
4675 static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
4676 const SwitchStmt *SS) {
4677 BlockScopeRAII Scope(Info);
4679 // Evaluate the switch condition.
4682 if (const Stmt *Init = SS->getInit()) {
4683 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
4684 if (ESR != ESR_Succeeded) {
4685 if (ESR != ESR_Failed && !Scope.destroy())
4691 FullExpressionRAII CondScope(Info);
4692 if (SS->getConditionVariable() &&
4693 !EvaluateDecl(Info, SS->getConditionVariable()))
4695 if (!EvaluateInteger(SS->getCond(), Value, Info))
4697 if (!CondScope.destroy())
4701 // Find the switch case corresponding to the value of the condition.
4702 // FIXME: Cache this lookup.
4703 const SwitchCase *Found = nullptr;
4704 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
4705 SC = SC->getNextSwitchCase()) {
4706 if (isa<DefaultStmt>(SC)) {
4711 const CaseStmt *CS = cast<CaseStmt>(SC);
4712 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx);
4713 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx)
4715 if (LHS <= Value && Value <= RHS) {
4722 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
4724 // Search the switch body for the switch case and evaluate it from there.
4725 EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found);
4726 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
4731 return ESR_Succeeded;
4737 case ESR_CaseNotFound:
4738 // This can only happen if the switch case is nested within a statement
4739 // expression. We have no intention of supporting that.
4740 Info.FFDiag(Found->getBeginLoc(),
4741 diag::note_constexpr_stmt_expr_unsupported);
4744 llvm_unreachable("Invalid EvalStmtResult!");
4747 // Evaluate a statement.
4748 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
4749 const Stmt *S, const SwitchCase *Case) {
4750 if (!Info.nextStep(S))
4753 // If we're hunting down a 'case' or 'default' label, recurse through
4754 // substatements until we hit the label.
4756 switch (S->getStmtClass()) {
4757 case Stmt::CompoundStmtClass:
4758 // FIXME: Precompute which substatement of a compound statement we
4759 // would jump to, and go straight there rather than performing a
4760 // linear scan each time.
4761 case Stmt::LabelStmtClass:
4762 case Stmt::AttributedStmtClass:
4763 case Stmt::DoStmtClass:
4766 case Stmt::CaseStmtClass:
4767 case Stmt::DefaultStmtClass:
4772 case Stmt::IfStmtClass: {
4773 // FIXME: Precompute which side of an 'if' we would jump to, and go
4774 // straight there rather than scanning both sides.
4775 const IfStmt *IS = cast<IfStmt>(S);
4777 // Wrap the evaluation in a block scope, in case it's a DeclStmt
4778 // preceded by our switch label.
4779 BlockScopeRAII Scope(Info);
4781 // Step into the init statement in case it brings an (uninitialized)
4782 // variable into scope.
4783 if (const Stmt *Init = IS->getInit()) {
4784 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case);
4785 if (ESR != ESR_CaseNotFound) {
4786 assert(ESR != ESR_Succeeded);
4791 // Condition variable must be initialized if it exists.
4792 // FIXME: We can skip evaluating the body if there's a condition
4793 // variable, as there can't be any case labels within it.
4794 // (The same is true for 'for' statements.)
4796 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case);
4797 if (ESR == ESR_Failed)
4799 if (ESR != ESR_CaseNotFound)
4800 return Scope.destroy() ? ESR : ESR_Failed;
4802 return ESR_CaseNotFound;
4804 ESR = EvaluateStmt(Result, Info, IS->getElse(), Case);
4805 if (ESR == ESR_Failed)
4807 if (ESR != ESR_CaseNotFound)
4808 return Scope.destroy() ? ESR : ESR_Failed;
4809 return ESR_CaseNotFound;
4812 case Stmt::WhileStmtClass: {
4813 EvalStmtResult ESR =
4814 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case);
4815 if (ESR != ESR_Continue)
4820 case Stmt::ForStmtClass: {
4821 const ForStmt *FS = cast<ForStmt>(S);
4822 BlockScopeRAII Scope(Info);
4824 // Step into the init statement in case it brings an (uninitialized)
4825 // variable into scope.
4826 if (const Stmt *Init = FS->getInit()) {
4827 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case);
4828 if (ESR != ESR_CaseNotFound) {
4829 assert(ESR != ESR_Succeeded);
4834 EvalStmtResult ESR =
4835 EvaluateLoopBody(Result, Info, FS->getBody(), Case);
4836 if (ESR != ESR_Continue)
4839 FullExpressionRAII IncScope(Info);
4840 if (!EvaluateIgnoredValue(Info, FS->getInc()) || !IncScope.destroy())
4846 case Stmt::DeclStmtClass: {
4847 // Start the lifetime of any uninitialized variables we encounter. They
4848 // might be used by the selected branch of the switch.
4849 const DeclStmt *DS = cast<DeclStmt>(S);
4850 for (const auto *D : DS->decls()) {
4851 if (const auto *VD = dyn_cast<VarDecl>(D)) {
4852 if (VD->hasLocalStorage() && !VD->getInit())
4853 if (!EvaluateVarDecl(Info, VD))
4855 // FIXME: If the variable has initialization that can't be jumped
4856 // over, bail out of any immediately-surrounding compound-statement
4857 // too. There can't be any case labels here.
4860 return ESR_CaseNotFound;
4864 return ESR_CaseNotFound;
4868 switch (S->getStmtClass()) {
4870 if (const Expr *E = dyn_cast<Expr>(S)) {
4871 // Don't bother evaluating beyond an expression-statement which couldn't
4873 // FIXME: Do we need the FullExpressionRAII object here?
4874 // VisitExprWithCleanups should create one when necessary.
4875 FullExpressionRAII Scope(Info);
4876 if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy())
4878 return ESR_Succeeded;
4881 Info.FFDiag(S->getBeginLoc());
4884 case Stmt::NullStmtClass:
4885 return ESR_Succeeded;
4887 case Stmt::DeclStmtClass: {
4888 const DeclStmt *DS = cast<DeclStmt>(S);
4889 for (const auto *D : DS->decls()) {
4890 // Each declaration initialization is its own full-expression.
4891 FullExpressionRAII Scope(Info);
4892 if (!EvaluateDecl(Info, D) && !Info.noteFailure())
4894 if (!Scope.destroy())
4897 return ESR_Succeeded;
4900 case Stmt::ReturnStmtClass: {
4901 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
4902 FullExpressionRAII Scope(Info);
4905 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr)
4906 : Evaluate(Result.Value, Info, RetExpr)))
4908 return Scope.destroy() ? ESR_Returned : ESR_Failed;
4911 case Stmt::CompoundStmtClass: {
4912 BlockScopeRAII Scope(Info);
4914 const CompoundStmt *CS = cast<CompoundStmt>(S);
4915 for (const auto *BI : CS->body()) {
4916 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case);
4917 if (ESR == ESR_Succeeded)
4919 else if (ESR != ESR_CaseNotFound) {
4920 if (ESR != ESR_Failed && !Scope.destroy())
4926 return ESR_CaseNotFound;
4927 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
4930 case Stmt::IfStmtClass: {
4931 const IfStmt *IS = cast<IfStmt>(S);
4933 // Evaluate the condition, as either a var decl or as an expression.
4934 BlockScopeRAII Scope(Info);
4935 if (const Stmt *Init = IS->getInit()) {
4936 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
4937 if (ESR != ESR_Succeeded) {
4938 if (ESR != ESR_Failed && !Scope.destroy())
4944 if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
4947 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
4948 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
4949 if (ESR != ESR_Succeeded) {
4950 if (ESR != ESR_Failed && !Scope.destroy())
4955 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
4958 case Stmt::WhileStmtClass: {
4959 const WhileStmt *WS = cast<WhileStmt>(S);
4961 BlockScopeRAII Scope(Info);
4963 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
4969 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
4970 if (ESR != ESR_Continue) {
4971 if (ESR != ESR_Failed && !Scope.destroy())
4975 if (!Scope.destroy())
4978 return ESR_Succeeded;
4981 case Stmt::DoStmtClass: {
4982 const DoStmt *DS = cast<DoStmt>(S);
4985 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case);
4986 if (ESR != ESR_Continue)
4990 FullExpressionRAII CondScope(Info);
4991 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info) ||
4992 !CondScope.destroy())
4995 return ESR_Succeeded;
4998 case Stmt::ForStmtClass: {
4999 const ForStmt *FS = cast<ForStmt>(S);
5000 BlockScopeRAII ForScope(Info);
5001 if (FS->getInit()) {
5002 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
5003 if (ESR != ESR_Succeeded) {
5004 if (ESR != ESR_Failed && !ForScope.destroy())
5010 BlockScopeRAII IterScope(Info);
5011 bool Continue = true;
5012 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
5013 FS->getCond(), Continue))
5018 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
5019 if (ESR != ESR_Continue) {
5020 if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy()))
5026 FullExpressionRAII IncScope(Info);
5027 if (!EvaluateIgnoredValue(Info, FS->getInc()) || !IncScope.destroy())
5031 if (!IterScope.destroy())
5034 return ForScope.destroy() ? ESR_Succeeded : ESR_Failed;
5037 case Stmt::CXXForRangeStmtClass: {
5038 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S);
5039 BlockScopeRAII Scope(Info);
5041 // Evaluate the init-statement if present.
5042 if (FS->getInit()) {
5043 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
5044 if (ESR != ESR_Succeeded) {
5045 if (ESR != ESR_Failed && !Scope.destroy())
5051 // Initialize the __range variable.
5052 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt());
5053 if (ESR != ESR_Succeeded) {
5054 if (ESR != ESR_Failed && !Scope.destroy())
5059 // Create the __begin and __end iterators.
5060 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt());
5061 if (ESR != ESR_Succeeded) {
5062 if (ESR != ESR_Failed && !Scope.destroy())
5066 ESR = EvaluateStmt(Result, Info, FS->getEndStmt());
5067 if (ESR != ESR_Succeeded) {
5068 if (ESR != ESR_Failed && !Scope.destroy())
5074 // Condition: __begin != __end.
5076 bool Continue = true;
5077 FullExpressionRAII CondExpr(Info);
5078 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info))
5084 // User's variable declaration, initialized by *__begin.
5085 BlockScopeRAII InnerScope(Info);
5086 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt());
5087 if (ESR != ESR_Succeeded) {
5088 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5094 ESR = EvaluateLoopBody(Result, Info, FS->getBody());
5095 if (ESR != ESR_Continue) {
5096 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5101 // Increment: ++__begin
5102 if (!EvaluateIgnoredValue(Info, FS->getInc()))
5105 if (!InnerScope.destroy())
5109 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5112 case Stmt::SwitchStmtClass:
5113 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S));
5115 case Stmt::ContinueStmtClass:
5116 return ESR_Continue;
5118 case Stmt::BreakStmtClass:
5121 case Stmt::LabelStmtClass:
5122 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case);
5124 case Stmt::AttributedStmtClass:
5125 // As a general principle, C++11 attributes can be ignored without
5126 // any semantic impact.
5127 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(),
5130 case Stmt::CaseStmtClass:
5131 case Stmt::DefaultStmtClass:
5132 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case);
5133 case Stmt::CXXTryStmtClass:
5134 // Evaluate try blocks by evaluating all sub statements.
5135 return EvaluateStmt(Result, Info, cast<CXXTryStmt>(S)->getTryBlock(), Case);
5139 /// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
5140 /// default constructor. If so, we'll fold it whether or not it's marked as
5141 /// constexpr. If it is marked as constexpr, we will never implicitly define it,
5142 /// so we need special handling.
5143 static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
5144 const CXXConstructorDecl *CD,
5145 bool IsValueInitialization) {
5146 if (!CD->isTrivial() || !CD->isDefaultConstructor())
5149 // Value-initialization does not call a trivial default constructor, so such a
5150 // call is a core constant expression whether or not the constructor is
5152 if (!CD->isConstexpr() && !IsValueInitialization) {
5153 if (Info.getLangOpts().CPlusPlus11) {
5154 // FIXME: If DiagDecl is an implicitly-declared special member function,
5155 // we should be much more explicit about why it's not constexpr.
5156 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
5157 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
5158 Info.Note(CD->getLocation(), diag::note_declared_at);
5160 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
5166 /// CheckConstexprFunction - Check that a function can be called in a constant
5168 static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
5169 const FunctionDecl *Declaration,
5170 const FunctionDecl *Definition,
5172 // Potential constant expressions can contain calls to declared, but not yet
5173 // defined, constexpr functions.
5174 if (Info.checkingPotentialConstantExpression() && !Definition &&
5175 Declaration->isConstexpr())
5178 // Bail out if the function declaration itself is invalid. We will
5179 // have produced a relevant diagnostic while parsing it, so just
5180 // note the problematic sub-expression.
5181 if (Declaration->isInvalidDecl()) {
5182 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5186 // DR1872: An instantiated virtual constexpr function can't be called in a
5187 // constant expression (prior to C++20). We can still constant-fold such a
5189 if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Declaration) &&
5190 cast<CXXMethodDecl>(Declaration)->isVirtual())
5191 Info.CCEDiag(CallLoc, diag::note_constexpr_virtual_call);
5193 if (Definition && Definition->isInvalidDecl()) {
5194 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5198 if (const auto *CtorDecl = dyn_cast_or_null<CXXConstructorDecl>(Definition)) {
5199 for (const auto *InitExpr : CtorDecl->inits()) {
5200 if (InitExpr->getInit() && InitExpr->getInit()->containsErrors())
5205 // Can we evaluate this function call?
5206 if (Definition && Definition->isConstexpr() && Body)
5209 if (Info.getLangOpts().CPlusPlus11) {
5210 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
5212 // If this function is not constexpr because it is an inherited
5213 // non-constexpr constructor, diagnose that directly.
5214 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
5215 if (CD && CD->isInheritingConstructor()) {
5216 auto *Inherited = CD->getInheritedConstructor().getConstructor();
5217 if (!Inherited->isConstexpr())
5218 DiagDecl = CD = Inherited;
5221 // FIXME: If DiagDecl is an implicitly-declared special member function
5222 // or an inheriting constructor, we should be much more explicit about why
5223 // it's not constexpr.
5224 if (CD && CD->isInheritingConstructor())
5225 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
5226 << CD->getInheritedConstructor().getConstructor()->getParent();
5228 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
5229 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
5230 Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
5232 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5238 struct CheckDynamicTypeHandler {
5239 AccessKinds AccessKind;
5240 typedef bool result_type;
5241 bool failed() { return false; }
5242 bool found(APValue &Subobj, QualType SubobjType) { return true; }
5243 bool found(APSInt &Value, QualType SubobjType) { return true; }
5244 bool found(APFloat &Value, QualType SubobjType) { return true; }
5246 } // end anonymous namespace
5248 /// Check that we can access the notional vptr of an object / determine its
5250 static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This,
5251 AccessKinds AK, bool Polymorphic) {
5252 if (This.Designator.Invalid)
5255 CompleteObject Obj = findCompleteObject(Info, E, AK, This, QualType());
5261 // The object is not usable in constant expressions, so we can't inspect
5262 // its value to see if it's in-lifetime or what the active union members
5263 // are. We can still check for a one-past-the-end lvalue.
5264 if (This.Designator.isOnePastTheEnd() ||
5265 This.Designator.isMostDerivedAnUnsizedArray()) {
5266 Info.FFDiag(E, This.Designator.isOnePastTheEnd()
5267 ? diag::note_constexpr_access_past_end
5268 : diag::note_constexpr_access_unsized_array)
5271 } else if (Polymorphic) {
5272 // Conservatively refuse to perform a polymorphic operation if we would
5273 // not be able to read a notional 'vptr' value.
5276 QualType StarThisType =
5277 Info.Ctx.getLValueReferenceType(This.Designator.getType(Info.Ctx));
5278 Info.FFDiag(E, diag::note_constexpr_polymorphic_unknown_dynamic_type)
5279 << AK << Val.getAsString(Info.Ctx, StarThisType);
5285 CheckDynamicTypeHandler Handler{AK};
5286 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
5289 /// Check that the pointee of the 'this' pointer in a member function call is
5290 /// either within its lifetime or in its period of construction or destruction.
5292 checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E,
5294 const CXXMethodDecl *NamedMember) {
5295 return checkDynamicType(
5297 isa<CXXDestructorDecl>(NamedMember) ? AK_Destroy : AK_MemberCall, false);
5300 struct DynamicType {
5301 /// The dynamic class type of the object.
5302 const CXXRecordDecl *Type;
5303 /// The corresponding path length in the lvalue.
5304 unsigned PathLength;
5307 static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator,
5308 unsigned PathLength) {
5309 assert(PathLength >= Designator.MostDerivedPathLength && PathLength <=
5310 Designator.Entries.size() && "invalid path length");
5311 return (PathLength == Designator.MostDerivedPathLength)
5312 ? Designator.MostDerivedType->getAsCXXRecordDecl()
5313 : getAsBaseClass(Designator.Entries[PathLength - 1]);
5316 /// Determine the dynamic type of an object.
5317 static Optional<DynamicType> ComputeDynamicType(EvalInfo &Info, const Expr *E,
5318 LValue &This, AccessKinds AK) {
5319 // If we don't have an lvalue denoting an object of class type, there is no
5320 // meaningful dynamic type. (We consider objects of non-class type to have no
5322 if (!checkDynamicType(Info, E, This, AK, true))
5325 // Refuse to compute a dynamic type in the presence of virtual bases. This
5326 // shouldn't happen other than in constant-folding situations, since literal
5327 // types can't have virtual bases.
5329 // Note that consumers of DynamicType assume that the type has no virtual
5330 // bases, and will need modifications if this restriction is relaxed.
5331 const CXXRecordDecl *Class =
5332 This.Designator.MostDerivedType->getAsCXXRecordDecl();
5333 if (!Class || Class->getNumVBases()) {
5338 // FIXME: For very deep class hierarchies, it might be beneficial to use a
5339 // binary search here instead. But the overwhelmingly common case is that
5340 // we're not in the middle of a constructor, so it probably doesn't matter
5342 ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries;
5343 for (unsigned PathLength = This.Designator.MostDerivedPathLength;
5344 PathLength <= Path.size(); ++PathLength) {
5345 switch (Info.isEvaluatingCtorDtor(This.getLValueBase(),
5346 Path.slice(0, PathLength))) {
5347 case ConstructionPhase::Bases:
5348 case ConstructionPhase::DestroyingBases:
5349 // We're constructing or destroying a base class. This is not the dynamic
5353 case ConstructionPhase::None:
5354 case ConstructionPhase::AfterBases:
5355 case ConstructionPhase::AfterFields:
5356 case ConstructionPhase::Destroying:
5357 // We've finished constructing the base classes and not yet started
5358 // destroying them again, so this is the dynamic type.
5359 return DynamicType{getBaseClassType(This.Designator, PathLength),
5364 // CWG issue 1517: we're constructing a base class of the object described by
5365 // 'This', so that object has not yet begun its period of construction and
5366 // any polymorphic operation on it results in undefined behavior.
5371 /// Perform virtual dispatch.
5372 static const CXXMethodDecl *HandleVirtualDispatch(
5373 EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found,
5374 llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) {
5375 Optional<DynamicType> DynType = ComputeDynamicType(
5377 isa<CXXDestructorDecl>(Found) ? AK_Destroy : AK_MemberCall);
5381 // Find the final overrider. It must be declared in one of the classes on the
5382 // path from the dynamic type to the static type.
5383 // FIXME: If we ever allow literal types to have virtual base classes, that
5385 const CXXMethodDecl *Callee = Found;
5386 unsigned PathLength = DynType->PathLength;
5387 for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) {
5388 const CXXRecordDecl *Class = getBaseClassType(This.Designator, PathLength);
5389 const CXXMethodDecl *Overrider =
5390 Found->getCorrespondingMethodDeclaredInClass(Class, false);
5397 // C++2a [class.abstract]p6:
5398 // the effect of making a virtual call to a pure virtual function [...] is
5400 if (Callee->isPure()) {
5401 Info.FFDiag(E, diag::note_constexpr_pure_virtual_call, 1) << Callee;
5402 Info.Note(Callee->getLocation(), diag::note_declared_at);
5406 // If necessary, walk the rest of the path to determine the sequence of
5407 // covariant adjustment steps to apply.
5408 if (!Info.Ctx.hasSameUnqualifiedType(Callee->getReturnType(),
5409 Found->getReturnType())) {
5410 CovariantAdjustmentPath.push_back(Callee->getReturnType());
5411 for (unsigned CovariantPathLength = PathLength + 1;
5412 CovariantPathLength != This.Designator.Entries.size();
5413 ++CovariantPathLength) {
5414 const CXXRecordDecl *NextClass =
5415 getBaseClassType(This.Designator, CovariantPathLength);
5416 const CXXMethodDecl *Next =
5417 Found->getCorrespondingMethodDeclaredInClass(NextClass, false);
5418 if (Next && !Info.Ctx.hasSameUnqualifiedType(
5419 Next->getReturnType(), CovariantAdjustmentPath.back()))
5420 CovariantAdjustmentPath.push_back(Next->getReturnType());
5422 if (!Info.Ctx.hasSameUnqualifiedType(Found->getReturnType(),
5423 CovariantAdjustmentPath.back()))
5424 CovariantAdjustmentPath.push_back(Found->getReturnType());
5427 // Perform 'this' adjustment.
5428 if (!CastToDerivedClass(Info, E, This, Callee->getParent(), PathLength))
5434 /// Perform the adjustment from a value returned by a virtual function to
5435 /// a value of the statically expected type, which may be a pointer or
5436 /// reference to a base class of the returned type.
5437 static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E,
5439 ArrayRef<QualType> Path) {
5440 assert(Result.isLValue() &&
5441 "unexpected kind of APValue for covariant return");
5442 if (Result.isNullPointer())
5446 LVal.setFrom(Info.Ctx, Result);
5448 const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl();
5449 for (unsigned I = 1; I != Path.size(); ++I) {
5450 const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl();
5451 assert(OldClass && NewClass && "unexpected kind of covariant return");
5452 if (OldClass != NewClass &&
5453 !CastToBaseClass(Info, E, LVal, OldClass, NewClass))
5455 OldClass = NewClass;
5458 LVal.moveInto(Result);
5462 /// Determine whether \p Base, which is known to be a direct base class of
5463 /// \p Derived, is a public base class.
5464 static bool isBaseClassPublic(const CXXRecordDecl *Derived,
5465 const CXXRecordDecl *Base) {
5466 for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) {
5467 auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl();
5468 if (BaseClass && declaresSameEntity(BaseClass, Base))
5469 return BaseSpec.getAccessSpecifier() == AS_public;
5471 llvm_unreachable("Base is not a direct base of Derived");
5474 /// Apply the given dynamic cast operation on the provided lvalue.
5476 /// This implements the hard case of dynamic_cast, requiring a "runtime check"
5477 /// to find a suitable target subobject.
5478 static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E,
5480 // We can't do anything with a non-symbolic pointer value.
5481 SubobjectDesignator &D = Ptr.Designator;
5485 // C++ [expr.dynamic.cast]p6:
5486 // If v is a null pointer value, the result is a null pointer value.
5487 if (Ptr.isNullPointer() && !E->isGLValue())
5490 // For all the other cases, we need the pointer to point to an object within
5491 // its lifetime / period of construction / destruction, and we need to know
5492 // its dynamic type.
5493 Optional<DynamicType> DynType =
5494 ComputeDynamicType(Info, E, Ptr, AK_DynamicCast);
5498 // C++ [expr.dynamic.cast]p7:
5499 // If T is "pointer to cv void", then the result is a pointer to the most
5501 if (E->getType()->isVoidPointerType())
5502 return CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength);
5504 const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl();
5505 assert(C && "dynamic_cast target is not void pointer nor class");
5506 CanQualType CQT = Info.Ctx.getCanonicalType(Info.Ctx.getRecordType(C));
5508 auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) {
5509 // C++ [expr.dynamic.cast]p9:
5510 if (!E->isGLValue()) {
5511 // The value of a failed cast to pointer type is the null pointer value
5512 // of the required result type.
5513 Ptr.setNull(Info.Ctx, E->getType());
5517 // A failed cast to reference type throws [...] std::bad_cast.
5519 if (!Paths && (declaresSameEntity(DynType->Type, C) ||
5520 DynType->Type->isDerivedFrom(C)))
5522 else if (!Paths || Paths->begin() == Paths->end())
5524 else if (Paths->isAmbiguous(CQT))
5527 assert(Paths->front().Access != AS_public && "why did the cast fail?");
5530 Info.FFDiag(E, diag::note_constexpr_dynamic_cast_to_reference_failed)
5531 << DiagKind << Ptr.Designator.getType(Info.Ctx)
5532 << Info.Ctx.getRecordType(DynType->Type)
5533 << E->getType().getUnqualifiedType();
5537 // Runtime check, phase 1:
5538 // Walk from the base subobject towards the derived object looking for the
5540 for (int PathLength = Ptr.Designator.Entries.size();
5541 PathLength >= (int)DynType->PathLength; --PathLength) {
5542 const CXXRecordDecl *Class = getBaseClassType(Ptr.Designator, PathLength);
5543 if (declaresSameEntity(Class, C))
5544 return CastToDerivedClass(Info, E, Ptr, Class, PathLength);
5545 // We can only walk across public inheritance edges.
5546 if (PathLength > (int)DynType->PathLength &&
5547 !isBaseClassPublic(getBaseClassType(Ptr.Designator, PathLength - 1),
5549 return RuntimeCheckFailed(nullptr);
5552 // Runtime check, phase 2:
5553 // Search the dynamic type for an unambiguous public base of type C.
5554 CXXBasePaths Paths(/*FindAmbiguities=*/true,
5555 /*RecordPaths=*/true, /*DetectVirtual=*/false);
5556 if (DynType->Type->isDerivedFrom(C, Paths) && !Paths.isAmbiguous(CQT) &&
5557 Paths.front().Access == AS_public) {
5558 // Downcast to the dynamic type...
5559 if (!CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength))
5561 // ... then upcast to the chosen base class subobject.
5562 for (CXXBasePathElement &Elem : Paths.front())
5563 if (!HandleLValueBase(Info, E, Ptr, Elem.Class, Elem.Base))
5568 // Otherwise, the runtime check fails.
5569 return RuntimeCheckFailed(&Paths);
5573 struct StartLifetimeOfUnionMemberHandler {
5575 const Expr *LHSExpr;
5576 const FieldDecl *Field;
5578 bool Failed = false;
5579 static const AccessKinds AccessKind = AK_Assign;
5581 typedef bool result_type;
5582 bool failed() { return Failed; }
5583 bool found(APValue &Subobj, QualType SubobjType) {
5584 // We are supposed to perform no initialization but begin the lifetime of
5585 // the object. We interpret that as meaning to do what default
5586 // initialization of the object would do if all constructors involved were
5588 // * All base, non-variant member, and array element subobjects' lifetimes
5590 // * No variant members' lifetimes begin
5591 // * All scalar subobjects whose lifetimes begin have indeterminate values
5592 assert(SubobjType->isUnionType());
5593 if (declaresSameEntity(Subobj.getUnionField(), Field)) {
5594 // This union member is already active. If it's also in-lifetime, there's
5596 if (Subobj.getUnionValue().hasValue())
5598 } else if (DuringInit) {
5599 // We're currently in the process of initializing a different union
5600 // member. If we carried on, that initialization would attempt to
5601 // store to an inactive union member, resulting in undefined behavior.
5602 Info.FFDiag(LHSExpr,
5603 diag::note_constexpr_union_member_change_during_init);
5607 Failed = !getDefaultInitValue(Field->getType(), Result);
5608 Subobj.setUnion(Field, Result);
5611 bool found(APSInt &Value, QualType SubobjType) {
5612 llvm_unreachable("wrong value kind for union object");
5614 bool found(APFloat &Value, QualType SubobjType) {
5615 llvm_unreachable("wrong value kind for union object");
5618 } // end anonymous namespace
5620 const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind;
5622 /// Handle a builtin simple-assignment or a call to a trivial assignment
5623 /// operator whose left-hand side might involve a union member access. If it
5624 /// does, implicitly start the lifetime of any accessed union elements per
5625 /// C++20 [class.union]5.
5626 static bool HandleUnionActiveMemberChange(EvalInfo &Info, const Expr *LHSExpr,
5627 const LValue &LHS) {
5628 if (LHS.InvalidBase || LHS.Designator.Invalid)
5631 llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths;
5632 // C++ [class.union]p5:
5633 // define the set S(E) of subexpressions of E as follows:
5634 unsigned PathLength = LHS.Designator.Entries.size();
5635 for (const Expr *E = LHSExpr; E != nullptr;) {
5636 // -- If E is of the form A.B, S(E) contains the elements of S(A)...
5637 if (auto *ME = dyn_cast<MemberExpr>(E)) {
5638 auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
5639 // Note that we can't implicitly start the lifetime of a reference,
5640 // so we don't need to proceed any further if we reach one.
5641 if (!FD || FD->getType()->isReferenceType())
5644 // ... and also contains A.B if B names a union member ...
5645 if (FD->getParent()->isUnion()) {
5646 // ... of a non-class, non-array type, or of a class type with a
5647 // trivial default constructor that is not deleted, or an array of
5650 FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
5651 if (!RD || RD->hasTrivialDefaultConstructor())
5652 UnionPathLengths.push_back({PathLength - 1, FD});
5657 assert(declaresSameEntity(FD,
5658 LHS.Designator.Entries[PathLength]
5659 .getAsBaseOrMember().getPointer()));
5661 // -- If E is of the form A[B] and is interpreted as a built-in array
5662 // subscripting operator, S(E) is [S(the array operand, if any)].
5663 } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(E)) {
5664 // Step over an ArrayToPointerDecay implicit cast.
5665 auto *Base = ASE->getBase()->IgnoreImplicit();
5666 if (!Base->getType()->isArrayType())
5672 } else if (auto *ICE = dyn_cast<ImplicitCastExpr>(E)) {
5673 // Step over a derived-to-base conversion.
5674 E = ICE->getSubExpr();
5675 if (ICE->getCastKind() == CK_NoOp)
5677 if (ICE->getCastKind() != CK_DerivedToBase &&
5678 ICE->getCastKind() != CK_UncheckedDerivedToBase)
5680 // Walk path backwards as we walk up from the base to the derived class.
5681 for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) {
5684 assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),
5685 LHS.Designator.Entries[PathLength]
5686 .getAsBaseOrMember().getPointer()));
5689 // -- Otherwise, S(E) is empty.
5695 // Common case: no unions' lifetimes are started.
5696 if (UnionPathLengths.empty())
5699 // if modification of X [would access an inactive union member], an object
5700 // of the type of X is implicitly created
5701 CompleteObject Obj =
5702 findCompleteObject(Info, LHSExpr, AK_Assign, LHS, LHSExpr->getType());
5705 for (std::pair<unsigned, const FieldDecl *> LengthAndField :
5706 llvm::reverse(UnionPathLengths)) {
5707 // Form a designator for the union object.
5708 SubobjectDesignator D = LHS.Designator;
5709 D.truncate(Info.Ctx, LHS.Base, LengthAndField.first);
5711 bool DuringInit = Info.isEvaluatingCtorDtor(LHS.Base, D.Entries) ==
5712 ConstructionPhase::AfterBases;
5713 StartLifetimeOfUnionMemberHandler StartLifetime{
5714 Info, LHSExpr, LengthAndField.second, DuringInit};
5715 if (!findSubobject(Info, LHSExpr, Obj, D, StartLifetime))
5723 typedef SmallVector<APValue, 8> ArgVector;
5726 /// EvaluateArgs - Evaluate the arguments to a function call.
5727 static bool EvaluateArgs(ArrayRef<const Expr *> Args, ArgVector &ArgValues,
5728 EvalInfo &Info, const FunctionDecl *Callee) {
5729 bool Success = true;
5730 llvm::SmallBitVector ForbiddenNullArgs;
5731 if (Callee->hasAttr<NonNullAttr>()) {
5732 ForbiddenNullArgs.resize(Args.size());
5733 for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) {
5734 if (!Attr->args_size()) {
5735 ForbiddenNullArgs.set();
5738 for (auto Idx : Attr->args()) {
5739 unsigned ASTIdx = Idx.getASTIndex();
5740 if (ASTIdx >= Args.size())
5742 ForbiddenNullArgs[ASTIdx] = 1;
5746 // FIXME: This is the wrong evaluation order for an assignment operator
5747 // called via operator syntax.
5748 for (unsigned Idx = 0; Idx < Args.size(); Idx++) {
5749 if (!Evaluate(ArgValues[Idx], Info, Args[Idx])) {
5750 // If we're checking for a potential constant expression, evaluate all
5751 // initializers even if some of them fail.
5752 if (!Info.noteFailure())
5755 } else if (!ForbiddenNullArgs.empty() &&
5756 ForbiddenNullArgs[Idx] &&
5757 ArgValues[Idx].isLValue() &&
5758 ArgValues[Idx].isNullPointer()) {
5759 Info.CCEDiag(Args[Idx], diag::note_non_null_attribute_failed);
5760 if (!Info.noteFailure())
5768 /// Evaluate a function call.
5769 static bool HandleFunctionCall(SourceLocation CallLoc,
5770 const FunctionDecl *Callee, const LValue *This,
5771 ArrayRef<const Expr*> Args, const Stmt *Body,
5772 EvalInfo &Info, APValue &Result,
5773 const LValue *ResultSlot) {
5774 ArgVector ArgValues(Args.size());
5775 if (!EvaluateArgs(Args, ArgValues, Info, Callee))
5778 if (!Info.CheckCallLimit(CallLoc))
5781 CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data());
5783 // For a trivial copy or move assignment, perform an APValue copy. This is
5784 // essential for unions, where the operations performed by the assignment
5785 // operator cannot be represented as statements.
5787 // Skip this for non-union classes with no fields; in that case, the defaulted
5788 // copy/move does not actually read the object.
5789 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee);
5790 if (MD && MD->isDefaulted() &&
5791 (MD->getParent()->isUnion() ||
5793 isReadByLvalueToRvalueConversion(MD->getParent())))) {
5795 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()));
5797 RHS.setFrom(Info.Ctx, ArgValues[0]);
5799 if (!handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(), RHS,
5800 RHSValue, MD->getParent()->isUnion()))
5802 if (Info.getLangOpts().CPlusPlus20 && MD->isTrivial() &&
5803 !HandleUnionActiveMemberChange(Info, Args[0], *This))
5805 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(),
5808 This->moveInto(Result);
5810 } else if (MD && isLambdaCallOperator(MD)) {
5811 // We're in a lambda; determine the lambda capture field maps unless we're
5812 // just constexpr checking a lambda's call operator. constexpr checking is
5813 // done before the captures have been added to the closure object (unless
5814 // we're inferring constexpr-ness), so we don't have access to them in this
5815 // case. But since we don't need the captures to constexpr check, we can
5816 // just ignore them.
5817 if (!Info.checkingPotentialConstantExpression())
5818 MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields,
5819 Frame.LambdaThisCaptureField);
5822 StmtResult Ret = {Result, ResultSlot};
5823 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body);
5824 if (ESR == ESR_Succeeded) {
5825 if (Callee->getReturnType()->isVoidType())
5827 Info.FFDiag(Callee->getEndLoc(), diag::note_constexpr_no_return);
5829 return ESR == ESR_Returned;
5832 /// Evaluate a constructor call.
5833 static bool HandleConstructorCall(const Expr *E, const LValue &This,
5835 const CXXConstructorDecl *Definition,
5836 EvalInfo &Info, APValue &Result) {
5837 SourceLocation CallLoc = E->getExprLoc();
5838 if (!Info.CheckCallLimit(CallLoc))
5841 const CXXRecordDecl *RD = Definition->getParent();
5842 if (RD->getNumVBases()) {
5843 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
5847 EvalInfo::EvaluatingConstructorRAII EvalObj(
5849 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
5851 CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues);
5853 // FIXME: Creating an APValue just to hold a nonexistent return value is
5856 StmtResult Ret = {RetVal, nullptr};
5858 // If it's a delegating constructor, delegate.
5859 if (Definition->isDelegatingConstructor()) {
5860 CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
5862 FullExpressionRAII InitScope(Info);
5863 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()) ||
5864 !InitScope.destroy())
5867 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
5870 // For a trivial copy or move constructor, perform an APValue copy. This is
5871 // essential for unions (or classes with anonymous union members), where the
5872 // operations performed by the constructor cannot be represented by
5873 // ctor-initializers.
5875 // Skip this for empty non-union classes; we should not perform an
5876 // lvalue-to-rvalue conversion on them because their copy constructor does not
5877 // actually read them.
5878 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
5879 (Definition->getParent()->isUnion() ||
5880 (Definition->isTrivial() &&
5881 isReadByLvalueToRvalueConversion(Definition->getParent())))) {
5883 RHS.setFrom(Info.Ctx, ArgValues[0]);
5884 return handleLValueToRValueConversion(
5885 Info, E, Definition->getParamDecl(0)->getType().getNonReferenceType(),
5886 RHS, Result, Definition->getParent()->isUnion());
5889 // Reserve space for the struct members.
5890 if (!Result.hasValue()) {
5892 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
5893 std::distance(RD->field_begin(), RD->field_end()));
5895 // A union starts with no active member.
5896 Result = APValue((const FieldDecl*)nullptr);
5899 if (RD->isInvalidDecl()) return false;
5900 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
5902 // A scope for temporaries lifetime-extended by reference members.
5903 BlockScopeRAII LifetimeExtendedScope(Info);
5905 bool Success = true;
5906 unsigned BasesSeen = 0;
5908 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
5910 CXXRecordDecl::field_iterator FieldIt = RD->field_begin();
5911 auto SkipToField = [&](FieldDecl *FD, bool Indirect) {
5912 // We might be initializing the same field again if this is an indirect
5913 // field initialization.
5914 if (FieldIt == RD->field_end() ||
5915 FieldIt->getFieldIndex() > FD->getFieldIndex()) {
5916 assert(Indirect && "fields out of order?");
5920 // Default-initialize any fields with no explicit initializer.
5921 for (; !declaresSameEntity(*FieldIt, FD); ++FieldIt) {
5922 assert(FieldIt != RD->field_end() && "missing field?");
5923 if (!FieldIt->isUnnamedBitfield())
5924 Success &= getDefaultInitValue(
5926 Result.getStructField(FieldIt->getFieldIndex()));
5930 for (const auto *I : Definition->inits()) {
5931 LValue Subobject = This;
5932 LValue SubobjectParent = This;
5933 APValue *Value = &Result;
5935 // Determine the subobject to initialize.
5936 FieldDecl *FD = nullptr;
5937 if (I->isBaseInitializer()) {
5938 QualType BaseType(I->getBaseClass(), 0);
5940 // Non-virtual base classes are initialized in the order in the class
5941 // definition. We have already checked for virtual base classes.
5942 assert(!BaseIt->isVirtual() && "virtual base for literal type");
5943 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
5944 "base class initializers not in expected order");
5947 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD,
5948 BaseType->getAsCXXRecordDecl(), &Layout))
5950 Value = &Result.getStructBase(BasesSeen++);
5951 } else if ((FD = I->getMember())) {
5952 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout))
5954 if (RD->isUnion()) {
5955 Result = APValue(FD);
5956 Value = &Result.getUnionValue();
5958 SkipToField(FD, false);
5959 Value = &Result.getStructField(FD->getFieldIndex());
5961 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
5962 // Walk the indirect field decl's chain to find the object to initialize,
5963 // and make sure we've initialized every step along it.
5964 auto IndirectFieldChain = IFD->chain();
5965 for (auto *C : IndirectFieldChain) {
5966 FD = cast<FieldDecl>(C);
5967 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
5968 // Switch the union field if it differs. This happens if we had
5969 // preceding zero-initialization, and we're now initializing a union
5970 // subobject other than the first.
5971 // FIXME: In this case, the values of the other subobjects are
5972 // specified, since zero-initialization sets all padding bits to zero.
5973 if (!Value->hasValue() ||
5974 (Value->isUnion() && Value->getUnionField() != FD)) {
5976 *Value = APValue(FD);
5978 // FIXME: This immediately starts the lifetime of all members of
5979 // an anonymous struct. It would be preferable to strictly start
5980 // member lifetime in initialization order.
5981 Success &= getDefaultInitValue(Info.Ctx.getRecordType(CD), *Value);
5983 // Store Subobject as its parent before updating it for the last element
5985 if (C == IndirectFieldChain.back())
5986 SubobjectParent = Subobject;
5987 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
5990 Value = &Value->getUnionValue();
5992 if (C == IndirectFieldChain.front() && !RD->isUnion())
5993 SkipToField(FD, true);
5994 Value = &Value->getStructField(FD->getFieldIndex());
5998 llvm_unreachable("unknown base initializer kind");
6001 // Need to override This for implicit field initializers as in this case
6002 // This refers to innermost anonymous struct/union containing initializer,
6003 // not to currently constructed class.
6004 const Expr *Init = I->getInit();
6005 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent,
6006 isa<CXXDefaultInitExpr>(Init));
6007 FullExpressionRAII InitScope(Info);
6008 if (!EvaluateInPlace(*Value, Info, Subobject, Init) ||
6009 (FD && FD->isBitField() &&
6010 !truncateBitfieldValue(Info, Init, *Value, FD))) {
6011 // If we're checking for a potential constant expression, evaluate all
6012 // initializers even if some of them fail.
6013 if (!Info.noteFailure())
6018 // This is the point at which the dynamic type of the object becomes this
6020 if (I->isBaseInitializer() && BasesSeen == RD->getNumBases())
6021 EvalObj.finishedConstructingBases();
6024 // Default-initialize any remaining fields.
6025 if (!RD->isUnion()) {
6026 for (; FieldIt != RD->field_end(); ++FieldIt) {
6027 if (!FieldIt->isUnnamedBitfield())
6028 Success &= getDefaultInitValue(
6030 Result.getStructField(FieldIt->getFieldIndex()));
6034 EvalObj.finishedConstructingFields();
6037 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed &&
6038 LifetimeExtendedScope.destroy();
6041 static bool HandleConstructorCall(const Expr *E, const LValue &This,
6042 ArrayRef<const Expr*> Args,
6043 const CXXConstructorDecl *Definition,
6044 EvalInfo &Info, APValue &Result) {
6045 ArgVector ArgValues(Args.size());
6046 if (!EvaluateArgs(Args, ArgValues, Info, Definition))
6049 return HandleConstructorCall(E, This, ArgValues.data(), Definition,
6053 static bool HandleDestructionImpl(EvalInfo &Info, SourceLocation CallLoc,
6054 const LValue &This, APValue &Value,
6056 // Objects can only be destroyed while they're within their lifetimes.
6057 // FIXME: We have no representation for whether an object of type nullptr_t
6058 // is in its lifetime; it usually doesn't matter. Perhaps we should model it
6059 // as indeterminate instead?
6060 if (Value.isAbsent() && !T->isNullPtrType()) {
6062 This.moveInto(Printable);
6063 Info.FFDiag(CallLoc, diag::note_constexpr_destroy_out_of_lifetime)
6064 << Printable.getAsString(Info.Ctx, Info.Ctx.getLValueReferenceType(T));
6068 // Invent an expression for location purposes.
6069 // FIXME: We shouldn't need to do this.
6070 OpaqueValueExpr LocE(CallLoc, Info.Ctx.IntTy, VK_RValue);
6072 // For arrays, destroy elements right-to-left.
6073 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T)) {
6074 uint64_t Size = CAT->getSize().getZExtValue();
6075 QualType ElemT = CAT->getElementType();
6077 LValue ElemLV = This;
6078 ElemLV.addArray(Info, &LocE, CAT);
6079 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, Size))
6082 // Ensure that we have actual array elements available to destroy; the
6083 // destructors might mutate the value, so we can't run them on the array
6085 if (Size && Size > Value.getArrayInitializedElts())
6086 expandArray(Value, Value.getArraySize() - 1);
6088 for (; Size != 0; --Size) {
6089 APValue &Elem = Value.getArrayInitializedElt(Size - 1);
6090 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, -1) ||
6091 !HandleDestructionImpl(Info, CallLoc, ElemLV, Elem, ElemT))
6095 // End the lifetime of this array now.
6100 const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
6102 if (T.isDestructedType()) {
6103 Info.FFDiag(CallLoc, diag::note_constexpr_unsupported_destruction) << T;
6111 if (RD->getNumVBases()) {
6112 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
6116 const CXXDestructorDecl *DD = RD->getDestructor();
6117 if (!DD && !RD->hasTrivialDestructor()) {
6118 Info.FFDiag(CallLoc);
6122 if (!DD || DD->isTrivial() ||
6123 (RD->isAnonymousStructOrUnion() && RD->isUnion())) {
6124 // A trivial destructor just ends the lifetime of the object. Check for
6125 // this case before checking for a body, because we might not bother
6126 // building a body for a trivial destructor. Note that it doesn't matter
6127 // whether the destructor is constexpr in this case; all trivial
6128 // destructors are constexpr.
6130 // If an anonymous union would be destroyed, some enclosing destructor must
6131 // have been explicitly defined, and the anonymous union destruction should
6137 if (!Info.CheckCallLimit(CallLoc))
6140 const FunctionDecl *Definition = nullptr;
6141 const Stmt *Body = DD->getBody(Definition);
6143 if (!CheckConstexprFunction(Info, CallLoc, DD, Definition, Body))
6146 CallStackFrame Frame(Info, CallLoc, Definition, &This, nullptr);
6148 // We're now in the period of destruction of this object.
6149 unsigned BasesLeft = RD->getNumBases();
6150 EvalInfo::EvaluatingDestructorRAII EvalObj(
6152 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries});
6153 if (!EvalObj.DidInsert) {
6154 // C++2a [class.dtor]p19:
6155 // the behavior is undefined if the destructor is invoked for an object
6156 // whose lifetime has ended
6157 // (Note that formally the lifetime ends when the period of destruction
6158 // begins, even though certain uses of the object remain valid until the
6159 // period of destruction ends.)
6160 Info.FFDiag(CallLoc, diag::note_constexpr_double_destroy);
6164 // FIXME: Creating an APValue just to hold a nonexistent return value is
6167 StmtResult Ret = {RetVal, nullptr};
6168 if (EvaluateStmt(Ret, Info, Definition->getBody()) == ESR_Failed)
6171 // A union destructor does not implicitly destroy its members.
6175 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6177 // We don't have a good way to iterate fields in reverse, so collect all the
6178 // fields first and then walk them backwards.
6179 SmallVector<FieldDecl*, 16> Fields(RD->field_begin(), RD->field_end());
6180 for (const FieldDecl *FD : llvm::reverse(Fields)) {
6181 if (FD->isUnnamedBitfield())
6184 LValue Subobject = This;
6185 if (!HandleLValueMember(Info, &LocE, Subobject, FD, &Layout))
6188 APValue *SubobjectValue = &Value.getStructField(FD->getFieldIndex());
6189 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue,
6195 EvalObj.startedDestroyingBases();
6197 // Destroy base classes in reverse order.
6198 for (const CXXBaseSpecifier &Base : llvm::reverse(RD->bases())) {
6201 QualType BaseType = Base.getType();
6202 LValue Subobject = This;
6203 if (!HandleLValueDirectBase(Info, &LocE, Subobject, RD,
6204 BaseType->getAsCXXRecordDecl(), &Layout))
6207 APValue *SubobjectValue = &Value.getStructBase(BasesLeft);
6208 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue,
6212 assert(BasesLeft == 0 && "NumBases was wrong?");
6214 // The period of destruction ends now. The object is gone.
6220 struct DestroyObjectHandler {
6224 const AccessKinds AccessKind;
6226 typedef bool result_type;
6227 bool failed() { return false; }
6228 bool found(APValue &Subobj, QualType SubobjType) {
6229 return HandleDestructionImpl(Info, E->getExprLoc(), This, Subobj,
6232 bool found(APSInt &Value, QualType SubobjType) {
6233 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
6236 bool found(APFloat &Value, QualType SubobjType) {
6237 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
6243 /// Perform a destructor or pseudo-destructor call on the given object, which
6244 /// might in general not be a complete object.
6245 static bool HandleDestruction(EvalInfo &Info, const Expr *E,
6246 const LValue &This, QualType ThisType) {
6247 CompleteObject Obj = findCompleteObject(Info, E, AK_Destroy, This, ThisType);
6248 DestroyObjectHandler Handler = {Info, E, This, AK_Destroy};
6249 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
6252 /// Destroy and end the lifetime of the given complete object.
6253 static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
6254 APValue::LValueBase LVBase, APValue &Value,
6256 // If we've had an unmodeled side-effect, we can't rely on mutable state
6257 // (such as the object we're about to destroy) being correct.
6258 if (Info.EvalStatus.HasSideEffects)
6263 return HandleDestructionImpl(Info, Loc, LV, Value, T);
6266 /// Perform a call to 'perator new' or to `__builtin_operator_new'.
6267 static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E,
6269 if (Info.checkingPotentialConstantExpression() ||
6270 Info.SpeculativeEvaluationDepth)
6273 // This is permitted only within a call to std::allocator<T>::allocate.
6274 auto Caller = Info.getStdAllocatorCaller("allocate");
6276 Info.FFDiag(E->getExprLoc(), Info.getLangOpts().CPlusPlus20
6277 ? diag::note_constexpr_new_untyped
6278 : diag::note_constexpr_new);
6282 QualType ElemType = Caller.ElemType;
6283 if (ElemType->isIncompleteType() || ElemType->isFunctionType()) {
6284 Info.FFDiag(E->getExprLoc(),
6285 diag::note_constexpr_new_not_complete_object_type)
6286 << (ElemType->isIncompleteType() ? 0 : 1) << ElemType;
6291 if (!EvaluateInteger(E->getArg(0), ByteSize, Info))
6293 bool IsNothrow = false;
6294 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) {
6295 EvaluateIgnoredValue(Info, E->getArg(I));
6296 IsNothrow |= E->getType()->isNothrowT();
6300 if (!HandleSizeof(Info, E->getExprLoc(), ElemType, ElemSize))
6302 APInt Size, Remainder;
6303 APInt ElemSizeAP(ByteSize.getBitWidth(), ElemSize.getQuantity());
6304 APInt::udivrem(ByteSize, ElemSizeAP, Size, Remainder);
6305 if (Remainder != 0) {
6306 // This likely indicates a bug in the implementation of 'std::allocator'.
6307 Info.FFDiag(E->getExprLoc(), diag::note_constexpr_operator_new_bad_size)
6308 << ByteSize << APSInt(ElemSizeAP, true) << ElemType;
6312 if (ByteSize.getActiveBits() > ConstantArrayType::getMaxSizeBits(Info.Ctx)) {
6314 Result.setNull(Info.Ctx, E->getType());
6318 Info.FFDiag(E, diag::note_constexpr_new_too_large) << APSInt(Size, true);
6322 QualType AllocType = Info.Ctx.getConstantArrayType(ElemType, Size, nullptr,
6323 ArrayType::Normal, 0);
6324 APValue *Val = Info.createHeapAlloc(E, AllocType, Result);
6325 *Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue());
6326 Result.addArray(Info, E, cast<ConstantArrayType>(AllocType));
6330 static bool hasVirtualDestructor(QualType T) {
6331 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
6332 if (CXXDestructorDecl *DD = RD->getDestructor())
6333 return DD->isVirtual();
6337 static const FunctionDecl *getVirtualOperatorDelete(QualType T) {
6338 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
6339 if (CXXDestructorDecl *DD = RD->getDestructor())
6340 return DD->isVirtual() ? DD->getOperatorDelete() : nullptr;
6344 /// Check that the given object is a suitable pointer to a heap allocation that
6345 /// still exists and is of the right kind for the purpose of a deletion.
6347 /// On success, returns the heap allocation to deallocate. On failure, produces
6348 /// a diagnostic and returns None.
6349 static Optional<DynAlloc *> CheckDeleteKind(EvalInfo &Info, const Expr *E,
6350 const LValue &Pointer,
6351 DynAlloc::Kind DeallocKind) {
6352 auto PointerAsString = [&] {
6353 return Pointer.toString(Info.Ctx, Info.Ctx.VoidPtrTy);
6356 DynamicAllocLValue DA = Pointer.Base.dyn_cast<DynamicAllocLValue>();
6358 Info.FFDiag(E, diag::note_constexpr_delete_not_heap_alloc)
6359 << PointerAsString();
6361 NoteLValueLocation(Info, Pointer.Base);
6365 Optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
6367 Info.FFDiag(E, diag::note_constexpr_double_delete);
6371 QualType AllocType = Pointer.Base.getDynamicAllocType();
6372 if (DeallocKind != (*Alloc)->getKind()) {
6373 Info.FFDiag(E, diag::note_constexpr_new_delete_mismatch)
6374 << DeallocKind << (*Alloc)->getKind() << AllocType;
6375 NoteLValueLocation(Info, Pointer.Base);
6379 bool Subobject = false;
6380 if (DeallocKind == DynAlloc::New) {
6381 Subobject = Pointer.Designator.MostDerivedPathLength != 0 ||
6382 Pointer.Designator.isOnePastTheEnd();
6384 Subobject = Pointer.Designator.Entries.size() != 1 ||
6385 Pointer.Designator.Entries[0].getAsArrayIndex() != 0;
6388 Info.FFDiag(E, diag::note_constexpr_delete_subobject)
6389 << PointerAsString() << Pointer.Designator.isOnePastTheEnd();
6396 // Perform a call to 'operator delete' or '__builtin_operator_delete'.
6397 bool HandleOperatorDeleteCall(EvalInfo &Info, const CallExpr *E) {
6398 if (Info.checkingPotentialConstantExpression() ||
6399 Info.SpeculativeEvaluationDepth)
6402 // This is permitted only within a call to std::allocator<T>::deallocate.
6403 if (!Info.getStdAllocatorCaller("deallocate")) {
6404 Info.FFDiag(E->getExprLoc());
6409 if (!EvaluatePointer(E->getArg(0), Pointer, Info))
6411 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I)
6412 EvaluateIgnoredValue(Info, E->getArg(I));
6414 if (Pointer.Designator.Invalid)
6417 // Deleting a null pointer has no effect.
6418 if (Pointer.isNullPointer())
6421 if (!CheckDeleteKind(Info, E, Pointer, DynAlloc::StdAllocator))
6424 Info.HeapAllocs.erase(Pointer.Base.get<DynamicAllocLValue>());
6428 //===----------------------------------------------------------------------===//
6429 // Generic Evaluation
6430 //===----------------------------------------------------------------------===//
6433 class BitCastBuffer {
6434 // FIXME: We're going to need bit-level granularity when we support
6436 // FIXME: Its possible under the C++ standard for 'char' to not be 8 bits, but
6437 // we don't support a host or target where that is the case. Still, we should
6438 // use a more generic type in case we ever do.
6439 SmallVector<Optional<unsigned char>, 32> Bytes;
6441 static_assert(std::numeric_limits<unsigned char>::digits >= 8,
6442 "Need at least 8 bit unsigned char");
6444 bool TargetIsLittleEndian;
6447 BitCastBuffer(CharUnits Width, bool TargetIsLittleEndian)
6448 : Bytes(Width.getQuantity()),
6449 TargetIsLittleEndian(TargetIsLittleEndian) {}
6452 bool readObject(CharUnits Offset, CharUnits Width,
6453 SmallVectorImpl<unsigned char> &Output) const {
6454 for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) {
6455 // If a byte of an integer is uninitialized, then the whole integer is
6457 if (!Bytes[I.getQuantity()])
6459 Output.push_back(*Bytes[I.getQuantity()]);
6461 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
6462 std::reverse(Output.begin(), Output.end());
6466 void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) {
6467 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
6468 std::reverse(Input.begin(), Input.end());
6471 for (unsigned char Byte : Input) {
6472 assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?");
6473 Bytes[Offset.getQuantity() + Index] = Byte;
6478 size_t size() { return Bytes.size(); }
6481 /// Traverse an APValue to produce an BitCastBuffer, emulating how the current
6482 /// target would represent the value at runtime.
6483 class APValueToBufferConverter {
6485 BitCastBuffer Buffer;
6486 const CastExpr *BCE;
6488 APValueToBufferConverter(EvalInfo &Info, CharUnits ObjectWidth,
6489 const CastExpr *BCE)
6491 Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()),
6494 bool visit(const APValue &Val, QualType Ty) {
6495 return visit(Val, Ty, CharUnits::fromQuantity(0));
6498 // Write out Val with type Ty into Buffer starting at Offset.
6499 bool visit(const APValue &Val, QualType Ty, CharUnits Offset) {
6500 assert((size_t)Offset.getQuantity() <= Buffer.size());
6502 // As a special case, nullptr_t has an indeterminate value.
6503 if (Ty->isNullPtrType())
6506 // Dig through Src to find the byte at SrcOffset.
6507 switch (Val.getKind()) {
6508 case APValue::Indeterminate:
6513 return visitInt(Val.getInt(), Ty, Offset);
6514 case APValue::Float:
6515 return visitFloat(Val.getFloat(), Ty, Offset);
6516 case APValue::Array:
6517 return visitArray(Val, Ty, Offset);
6518 case APValue::Struct:
6519 return visitRecord(Val, Ty, Offset);
6521 case APValue::ComplexInt:
6522 case APValue::ComplexFloat:
6523 case APValue::Vector:
6524 case APValue::FixedPoint:
6525 // FIXME: We should support these.
6527 case APValue::Union:
6528 case APValue::MemberPointer:
6529 case APValue::AddrLabelDiff: {
6530 Info.FFDiag(BCE->getBeginLoc(),
6531 diag::note_constexpr_bit_cast_unsupported_type)
6536 case APValue::LValue:
6537 llvm_unreachable("LValue subobject in bit_cast?");
6539 llvm_unreachable("Unhandled APValue::ValueKind");
6542 bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) {
6543 const RecordDecl *RD = Ty->getAsRecordDecl();
6544 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6546 // Visit the base classes.
6547 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
6548 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
6549 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
6550 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
6552 if (!visitRecord(Val.getStructBase(I), BS.getType(),
6553 Layout.getBaseClassOffset(BaseDecl) + Offset))
6558 // Visit the fields.
6559 unsigned FieldIdx = 0;
6560 for (FieldDecl *FD : RD->fields()) {
6561 if (FD->isBitField()) {
6562 Info.FFDiag(BCE->getBeginLoc(),
6563 diag::note_constexpr_bit_cast_unsupported_bitfield);
6567 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
6569 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0 &&
6570 "only bit-fields can have sub-char alignment");
6571 CharUnits FieldOffset =
6572 Info.Ctx.toCharUnitsFromBits(FieldOffsetBits) + Offset;
6573 QualType FieldTy = FD->getType();
6574 if (!visit(Val.getStructField(FieldIdx), FieldTy, FieldOffset))
6582 bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) {
6584 dyn_cast_or_null<ConstantArrayType>(Ty->getAsArrayTypeUnsafe());
6588 CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(CAT->getElementType());
6589 unsigned NumInitializedElts = Val.getArrayInitializedElts();
6590 unsigned ArraySize = Val.getArraySize();
6591 // First, initialize the initialized elements.
6592 for (unsigned I = 0; I != NumInitializedElts; ++I) {
6593 const APValue &SubObj = Val.getArrayInitializedElt(I);
6594 if (!visit(SubObj, CAT->getElementType(), Offset + I * ElemWidth))
6598 // Next, initialize the rest of the array using the filler.
6599 if (Val.hasArrayFiller()) {
6600 const APValue &Filler = Val.getArrayFiller();
6601 for (unsigned I = NumInitializedElts; I != ArraySize; ++I) {
6602 if (!visit(Filler, CAT->getElementType(), Offset + I * ElemWidth))
6610 bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) {
6611 CharUnits Width = Info.Ctx.getTypeSizeInChars(Ty);
6612 SmallVector<unsigned char, 8> Bytes(Width.getQuantity());
6613 llvm::StoreIntToMemory(Val, &*Bytes.begin(), Width.getQuantity());
6614 Buffer.writeObject(Offset, Bytes);
6618 bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) {
6619 APSInt AsInt(Val.bitcastToAPInt());
6620 return visitInt(AsInt, Ty, Offset);
6624 static Optional<BitCastBuffer> convert(EvalInfo &Info, const APValue &Src,
6625 const CastExpr *BCE) {
6626 CharUnits DstSize = Info.Ctx.getTypeSizeInChars(BCE->getType());
6627 APValueToBufferConverter Converter(Info, DstSize, BCE);
6628 if (!Converter.visit(Src, BCE->getSubExpr()->getType()))
6630 return Converter.Buffer;
6634 /// Write an BitCastBuffer into an APValue.
6635 class BufferToAPValueConverter {
6637 const BitCastBuffer &Buffer;
6638 const CastExpr *BCE;
6640 BufferToAPValueConverter(EvalInfo &Info, const BitCastBuffer &Buffer,
6641 const CastExpr *BCE)
6642 : Info(Info), Buffer(Buffer), BCE(BCE) {}
6644 // Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast
6645 // with an invalid type, so anything left is a deficiency on our part (FIXME).
6646 // Ideally this will be unreachable.
6647 llvm::NoneType unsupportedType(QualType Ty) {
6648 Info.FFDiag(BCE->getBeginLoc(),
6649 diag::note_constexpr_bit_cast_unsupported_type)
6654 Optional<APValue> visit(const BuiltinType *T, CharUnits Offset,
6655 const EnumType *EnumSugar = nullptr) {
6656 if (T->isNullPtrType()) {
6657 uint64_t NullValue = Info.Ctx.getTargetNullPointerValue(QualType(T, 0));
6658 return APValue((Expr *)nullptr,
6659 /*Offset=*/CharUnits::fromQuantity(NullValue),
6660 APValue::NoLValuePath{}, /*IsNullPtr=*/true);
6663 CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T);
6664 SmallVector<uint8_t, 8> Bytes;
6665 if (!Buffer.readObject(Offset, SizeOf, Bytes)) {
6666 // If this is std::byte or unsigned char, then its okay to store an
6667 // indeterminate value.
6668 bool IsStdByte = EnumSugar && EnumSugar->isStdByteType();
6670 !EnumSugar && (T->isSpecificBuiltinType(BuiltinType::UChar) ||
6671 T->isSpecificBuiltinType(BuiltinType::Char_U));
6672 if (!IsStdByte && !IsUChar) {
6673 QualType DisplayType(EnumSugar ? (const Type *)EnumSugar : T, 0);
6674 Info.FFDiag(BCE->getExprLoc(),
6675 diag::note_constexpr_bit_cast_indet_dest)
6676 << DisplayType << Info.Ctx.getLangOpts().CharIsSigned;
6680 return APValue::IndeterminateValue();
6683 APSInt Val(SizeOf.getQuantity() * Info.Ctx.getCharWidth(), true);
6684 llvm::LoadIntFromMemory(Val, &*Bytes.begin(), Bytes.size());
6686 if (T->isIntegralOrEnumerationType()) {
6687 Val.setIsSigned(T->isSignedIntegerOrEnumerationType());
6688 return APValue(Val);
6691 if (T->isRealFloatingType()) {
6692 const llvm::fltSemantics &Semantics =
6693 Info.Ctx.getFloatTypeSemantics(QualType(T, 0));
6694 return APValue(APFloat(Semantics, Val));
6697 return unsupportedType(QualType(T, 0));
6700 Optional<APValue> visit(const RecordType *RTy, CharUnits Offset) {
6701 const RecordDecl *RD = RTy->getAsRecordDecl();
6702 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6704 unsigned NumBases = 0;
6705 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
6706 NumBases = CXXRD->getNumBases();
6708 APValue ResultVal(APValue::UninitStruct(), NumBases,
6709 std::distance(RD->field_begin(), RD->field_end()));
6711 // Visit the base classes.
6712 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
6713 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
6714 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
6715 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
6716 if (BaseDecl->isEmpty() ||
6717 Info.Ctx.getASTRecordLayout(BaseDecl).getNonVirtualSize().isZero())
6720 Optional<APValue> SubObj = visitType(
6721 BS.getType(), Layout.getBaseClassOffset(BaseDecl) + Offset);
6724 ResultVal.getStructBase(I) = *SubObj;
6728 // Visit the fields.
6729 unsigned FieldIdx = 0;
6730 for (FieldDecl *FD : RD->fields()) {
6731 // FIXME: We don't currently support bit-fields. A lot of the logic for
6732 // this is in CodeGen, so we need to factor it around.
6733 if (FD->isBitField()) {
6734 Info.FFDiag(BCE->getBeginLoc(),
6735 diag::note_constexpr_bit_cast_unsupported_bitfield);
6739 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
6740 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0);
6742 CharUnits FieldOffset =
6743 CharUnits::fromQuantity(FieldOffsetBits / Info.Ctx.getCharWidth()) +
6745 QualType FieldTy = FD->getType();
6746 Optional<APValue> SubObj = visitType(FieldTy, FieldOffset);
6749 ResultVal.getStructField(FieldIdx) = *SubObj;
6756 Optional<APValue> visit(const EnumType *Ty, CharUnits Offset) {
6757 QualType RepresentationType = Ty->getDecl()->getIntegerType();
6758 assert(!RepresentationType.isNull() &&
6759 "enum forward decl should be caught by Sema");
6760 const auto *AsBuiltin =
6761 RepresentationType.getCanonicalType()->castAs<BuiltinType>();
6762 // Recurse into the underlying type. Treat std::byte transparently as
6764 return visit(AsBuiltin, Offset, /*EnumTy=*/Ty);
6767 Optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) {
6768 size_t Size = Ty->getSize().getLimitedValue();
6769 CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(Ty->getElementType());
6771 APValue ArrayValue(APValue::UninitArray(), Size, Size);
6772 for (size_t I = 0; I != Size; ++I) {
6773 Optional<APValue> ElementValue =
6774 visitType(Ty->getElementType(), Offset + I * ElementWidth);
6777 ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue);
6783 Optional<APValue> visit(const Type *Ty, CharUnits Offset) {
6784 return unsupportedType(QualType(Ty, 0));
6787 Optional<APValue> visitType(QualType Ty, CharUnits Offset) {
6788 QualType Can = Ty.getCanonicalType();
6790 switch (Can->getTypeClass()) {
6791 #define TYPE(Class, Base) \
6793 return visit(cast<Class##Type>(Can.getTypePtr()), Offset);
6794 #define ABSTRACT_TYPE(Class, Base)
6795 #define NON_CANONICAL_TYPE(Class, Base) \
6797 llvm_unreachable("non-canonical type should be impossible!");
6798 #define DEPENDENT_TYPE(Class, Base) \
6801 "dependent types aren't supported in the constant evaluator!");
6802 #define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base) \
6804 llvm_unreachable("either dependent or not canonical!");
6805 #include "clang/AST/TypeNodes.inc"
6807 llvm_unreachable("Unhandled Type::TypeClass");
6811 // Pull out a full value of type DstType.
6812 static Optional<APValue> convert(EvalInfo &Info, BitCastBuffer &Buffer,
6813 const CastExpr *BCE) {
6814 BufferToAPValueConverter Converter(Info, Buffer, BCE);
6815 return Converter.visitType(BCE->getType(), CharUnits::fromQuantity(0));
6819 static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
6820 QualType Ty, EvalInfo *Info,
6821 const ASTContext &Ctx,
6822 bool CheckingDest) {
6823 Ty = Ty.getCanonicalType();
6825 auto diag = [&](int Reason) {
6827 Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_type)
6828 << CheckingDest << (Reason == 4) << Reason;
6831 auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) {
6833 Info->Note(NoteLoc, diag::note_constexpr_bit_cast_invalid_subtype)
6834 << NoteTy << Construct << Ty;
6838 if (Ty->isUnionType())
6840 if (Ty->isPointerType())
6842 if (Ty->isMemberPointerType())
6844 if (Ty.isVolatileQualified())
6847 if (RecordDecl *Record = Ty->getAsRecordDecl()) {
6848 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Record)) {
6849 for (CXXBaseSpecifier &BS : CXXRD->bases())
6850 if (!checkBitCastConstexprEligibilityType(Loc, BS.getType(), Info, Ctx,
6852 return note(1, BS.getType(), BS.getBeginLoc());
6854 for (FieldDecl *FD : Record->fields()) {
6855 if (FD->getType()->isReferenceType())
6857 if (!checkBitCastConstexprEligibilityType(Loc, FD->getType(), Info, Ctx,
6859 return note(0, FD->getType(), FD->getBeginLoc());
6863 if (Ty->isArrayType() &&
6864 !checkBitCastConstexprEligibilityType(Loc, Ctx.getBaseElementType(Ty),
6865 Info, Ctx, CheckingDest))
6871 static bool checkBitCastConstexprEligibility(EvalInfo *Info,
6872 const ASTContext &Ctx,
6873 const CastExpr *BCE) {
6874 bool DestOK = checkBitCastConstexprEligibilityType(
6875 BCE->getBeginLoc(), BCE->getType(), Info, Ctx, true);
6876 bool SourceOK = DestOK && checkBitCastConstexprEligibilityType(
6878 BCE->getSubExpr()->getType(), Info, Ctx, false);
6882 static bool handleLValueToRValueBitCast(EvalInfo &Info, APValue &DestValue,
6883 APValue &SourceValue,
6884 const CastExpr *BCE) {
6885 assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 &&
6886 "no host or target supports non 8-bit chars");
6887 assert(SourceValue.isLValue() &&
6888 "LValueToRValueBitcast requires an lvalue operand!");
6890 if (!checkBitCastConstexprEligibility(&Info, Info.Ctx, BCE))
6893 LValue SourceLValue;
6894 APValue SourceRValue;
6895 SourceLValue.setFrom(Info.Ctx, SourceValue);
6896 if (!handleLValueToRValueConversion(
6897 Info, BCE, BCE->getSubExpr()->getType().withConst(), SourceLValue,
6898 SourceRValue, /*WantObjectRepresentation=*/true))
6901 // Read out SourceValue into a char buffer.
6902 Optional<BitCastBuffer> Buffer =
6903 APValueToBufferConverter::convert(Info, SourceRValue, BCE);
6907 // Write out the buffer into a new APValue.
6908 Optional<APValue> MaybeDestValue =
6909 BufferToAPValueConverter::convert(Info, *Buffer, BCE);
6910 if (!MaybeDestValue)
6913 DestValue = std::move(*MaybeDestValue);
6917 template <class Derived>
6918 class ExprEvaluatorBase
6919 : public ConstStmtVisitor<Derived, bool> {
6921 Derived &getDerived() { return static_cast<Derived&>(*this); }
6922 bool DerivedSuccess(const APValue &V, const Expr *E) {
6923 return getDerived().Success(V, E);
6925 bool DerivedZeroInitialization(const Expr *E) {
6926 return getDerived().ZeroInitialization(E);
6929 // Check whether a conditional operator with a non-constant condition is a
6930 // potential constant expression. If neither arm is a potential constant
6931 // expression, then the conditional operator is not either.
6932 template<typename ConditionalOperator>
6933 void CheckPotentialConstantConditional(const ConditionalOperator *E) {
6934 assert(Info.checkingPotentialConstantExpression());
6936 // Speculatively evaluate both arms.
6937 SmallVector<PartialDiagnosticAt, 8> Diag;
6939 SpeculativeEvaluationRAII Speculate(Info, &Diag);
6940 StmtVisitorTy::Visit(E->getFalseExpr());
6946 SpeculativeEvaluationRAII Speculate(Info, &Diag);
6948 StmtVisitorTy::Visit(E->getTrueExpr());
6953 Error(E, diag::note_constexpr_conditional_never_const);
6957 template<typename ConditionalOperator>
6958 bool HandleConditionalOperator(const ConditionalOperator *E) {
6960 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
6961 if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) {
6962 CheckPotentialConstantConditional(E);
6965 if (Info.noteFailure()) {
6966 StmtVisitorTy::Visit(E->getTrueExpr());
6967 StmtVisitorTy::Visit(E->getFalseExpr());
6972 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
6973 return StmtVisitorTy::Visit(EvalExpr);
6978 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
6979 typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
6981 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
6982 return Info.CCEDiag(E, D);
6985 bool ZeroInitialization(const Expr *E) { return Error(E); }
6988 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
6990 EvalInfo &getEvalInfo() { return Info; }
6992 /// Report an evaluation error. This should only be called when an error is
6993 /// first discovered. When propagating an error, just return false.
6994 bool Error(const Expr *E, diag::kind D) {
6998 bool Error(const Expr *E) {
6999 return Error(E, diag::note_invalid_subexpr_in_const_expr);
7002 bool VisitStmt(const Stmt *) {
7003 llvm_unreachable("Expression evaluator should not be called on stmts");
7005 bool VisitExpr(const Expr *E) {
7009 bool VisitConstantExpr(const ConstantExpr *E) {
7010 if (E->hasAPValueResult())
7011 return DerivedSuccess(E->getAPValueResult(), E);
7013 return StmtVisitorTy::Visit(E->getSubExpr());
7016 bool VisitParenExpr(const ParenExpr *E)
7017 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7018 bool VisitUnaryExtension(const UnaryOperator *E)
7019 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7020 bool VisitUnaryPlus(const UnaryOperator *E)
7021 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7022 bool VisitChooseExpr(const ChooseExpr *E)
7023 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
7024 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
7025 { return StmtVisitorTy::Visit(E->getResultExpr()); }
7026 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
7027 { return StmtVisitorTy::Visit(E->getReplacement()); }
7028 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) {
7029 TempVersionRAII RAII(*Info.CurrentCall);
7030 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
7031 return StmtVisitorTy::Visit(E->getExpr());
7033 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
7034 TempVersionRAII RAII(*Info.CurrentCall);
7035 // The initializer may not have been parsed yet, or might be erroneous.
7038 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
7039 return StmtVisitorTy::Visit(E->getExpr());
7042 bool VisitExprWithCleanups(const ExprWithCleanups *E) {
7043 FullExpressionRAII Scope(Info);
7044 return StmtVisitorTy::Visit(E->getSubExpr()) && Scope.destroy();
7047 // Temporaries are registered when created, so we don't care about
7048 // CXXBindTemporaryExpr.
7049 bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
7050 return StmtVisitorTy::Visit(E->getSubExpr());
7053 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
7054 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
7055 return static_cast<Derived*>(this)->VisitCastExpr(E);
7057 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
7058 if (!Info.Ctx.getLangOpts().CPlusPlus20)
7059 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
7060 return static_cast<Derived*>(this)->VisitCastExpr(E);
7062 bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) {
7063 return static_cast<Derived*>(this)->VisitCastExpr(E);
7066 bool VisitBinaryOperator(const BinaryOperator *E) {
7067 switch (E->getOpcode()) {
7072 VisitIgnoredValue(E->getLHS());
7073 return StmtVisitorTy::Visit(E->getRHS());
7078 if (!HandleMemberPointerAccess(Info, E, Obj))
7081 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
7083 return DerivedSuccess(Result, E);
7088 bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E) {
7089 return StmtVisitorTy::Visit(E->getSemanticForm());
7092 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
7093 // Evaluate and cache the common expression. We treat it as a temporary,
7094 // even though it's not quite the same thing.
7096 if (!Evaluate(Info.CurrentCall->createTemporary(
7097 E->getOpaqueValue(),
7098 getStorageType(Info.Ctx, E->getOpaqueValue()), false,
7100 Info, E->getCommon()))
7103 return HandleConditionalOperator(E);
7106 bool VisitConditionalOperator(const ConditionalOperator *E) {
7107 bool IsBcpCall = false;
7108 // If the condition (ignoring parens) is a __builtin_constant_p call,
7109 // the result is a constant expression if it can be folded without
7110 // side-effects. This is an important GNU extension. See GCC PR38377
7112 if (const CallExpr *CallCE =
7113 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
7114 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
7117 // Always assume __builtin_constant_p(...) ? ... : ... is a potential
7118 // constant expression; we can't check whether it's potentially foldable.
7119 // FIXME: We should instead treat __builtin_constant_p as non-constant if
7120 // it would return 'false' in this mode.
7121 if (Info.checkingPotentialConstantExpression() && IsBcpCall)
7124 FoldConstant Fold(Info, IsBcpCall);
7125 if (!HandleConditionalOperator(E)) {
7126 Fold.keepDiagnostics();
7133 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
7134 if (APValue *Value = Info.CurrentCall->getCurrentTemporary(E))
7135 return DerivedSuccess(*Value, E);
7137 const Expr *Source = E->getSourceExpr();
7140 if (Source == E) { // sanity checking.
7141 assert(0 && "OpaqueValueExpr recursively refers to itself");
7144 return StmtVisitorTy::Visit(Source);
7147 bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) {
7148 for (const Expr *SemE : E->semantics()) {
7149 if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) {
7150 // FIXME: We can't handle the case where an OpaqueValueExpr is also the
7151 // result expression: there could be two different LValues that would
7152 // refer to the same object in that case, and we can't model that.
7153 if (SemE == E->getResultExpr())
7156 // Unique OVEs get evaluated if and when we encounter them when
7157 // emitting the rest of the semantic form, rather than eagerly.
7158 if (OVE->isUnique())
7162 if (!Evaluate(Info.CurrentCall->createTemporary(
7163 OVE, getStorageType(Info.Ctx, OVE), false, LV),
7164 Info, OVE->getSourceExpr()))
7166 } else if (SemE == E->getResultExpr()) {
7167 if (!StmtVisitorTy::Visit(SemE))
7170 if (!EvaluateIgnoredValue(Info, SemE))
7177 bool VisitCallExpr(const CallExpr *E) {
7179 if (!handleCallExpr(E, Result, nullptr))
7181 return DerivedSuccess(Result, E);
7184 bool handleCallExpr(const CallExpr *E, APValue &Result,
7185 const LValue *ResultSlot) {
7186 const Expr *Callee = E->getCallee()->IgnoreParens();
7187 QualType CalleeType = Callee->getType();
7189 const FunctionDecl *FD = nullptr;
7190 LValue *This = nullptr, ThisVal;
7191 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
7192 bool HasQualifier = false;
7194 // Extract function decl and 'this' pointer from the callee.
7195 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
7196 const CXXMethodDecl *Member = nullptr;
7197 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
7198 // Explicit bound member calls, such as x.f() or p->g();
7199 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
7201 Member = dyn_cast<CXXMethodDecl>(ME->getMemberDecl());
7203 return Error(Callee);
7205 HasQualifier = ME->hasQualifier();
7206 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
7207 // Indirect bound member calls ('.*' or '->*').
7208 const ValueDecl *D =
7209 HandleMemberPointerAccess(Info, BE, ThisVal, false);
7212 Member = dyn_cast<CXXMethodDecl>(D);
7214 return Error(Callee);
7216 } else if (const auto *PDE = dyn_cast<CXXPseudoDestructorExpr>(Callee)) {
7217 if (!Info.getLangOpts().CPlusPlus20)
7218 Info.CCEDiag(PDE, diag::note_constexpr_pseudo_destructor);
7219 return EvaluateObjectArgument(Info, PDE->getBase(), ThisVal) &&
7220 HandleDestruction(Info, PDE, ThisVal, PDE->getDestroyedType());
7222 return Error(Callee);
7224 } else if (CalleeType->isFunctionPointerType()) {
7226 if (!EvaluatePointer(Callee, Call, Info))
7229 if (!Call.getLValueOffset().isZero())
7230 return Error(Callee);
7231 FD = dyn_cast_or_null<FunctionDecl>(
7232 Call.getLValueBase().dyn_cast<const ValueDecl*>());
7234 return Error(Callee);
7235 // Don't call function pointers which have been cast to some other type.
7236 // Per DR (no number yet), the caller and callee can differ in noexcept.
7237 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
7238 CalleeType->getPointeeType(), FD->getType())) {
7242 // Overloaded operator calls to member functions are represented as normal
7243 // calls with '*this' as the first argument.
7244 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
7245 if (MD && !MD->isStatic()) {
7246 // FIXME: When selecting an implicit conversion for an overloaded
7247 // operator delete, we sometimes try to evaluate calls to conversion
7248 // operators without a 'this' parameter!
7252 if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
7255 Args = Args.slice(1);
7256 } else if (MD && MD->isLambdaStaticInvoker()) {
7257 // Map the static invoker for the lambda back to the call operator.
7258 // Conveniently, we don't have to slice out the 'this' argument (as is
7259 // being done for the non-static case), since a static member function
7260 // doesn't have an implicit argument passed in.
7261 const CXXRecordDecl *ClosureClass = MD->getParent();
7263 ClosureClass->captures_begin() == ClosureClass->captures_end() &&
7264 "Number of captures must be zero for conversion to function-ptr");
7266 const CXXMethodDecl *LambdaCallOp =
7267 ClosureClass->getLambdaCallOperator();
7269 // Set 'FD', the function that will be called below, to the call
7270 // operator. If the closure object represents a generic lambda, find
7271 // the corresponding specialization of the call operator.
7273 if (ClosureClass->isGenericLambda()) {
7274 assert(MD->isFunctionTemplateSpecialization() &&
7275 "A generic lambda's static-invoker function must be a "
7276 "template specialization");
7277 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
7278 FunctionTemplateDecl *CallOpTemplate =
7279 LambdaCallOp->getDescribedFunctionTemplate();
7280 void *InsertPos = nullptr;
7281 FunctionDecl *CorrespondingCallOpSpecialization =
7282 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
7283 assert(CorrespondingCallOpSpecialization &&
7284 "We must always have a function call operator specialization "
7285 "that corresponds to our static invoker specialization");
7286 FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
7289 } else if (FD->isReplaceableGlobalAllocationFunction()) {
7290 if (FD->getDeclName().getCXXOverloadedOperator() == OO_New ||
7291 FD->getDeclName().getCXXOverloadedOperator() == OO_Array_New) {
7293 if (!HandleOperatorNewCall(Info, E, Ptr))
7295 Ptr.moveInto(Result);
7298 return HandleOperatorDeleteCall(Info, E);
7304 SmallVector<QualType, 4> CovariantAdjustmentPath;
7306 auto *NamedMember = dyn_cast<CXXMethodDecl>(FD);
7307 if (NamedMember && NamedMember->isVirtual() && !HasQualifier) {
7308 // Perform virtual dispatch, if necessary.
7309 FD = HandleVirtualDispatch(Info, E, *This, NamedMember,
7310 CovariantAdjustmentPath);
7314 // Check that the 'this' pointer points to an object of the right type.
7315 // FIXME: If this is an assignment operator call, we may need to change
7316 // the active union member before we check this.
7317 if (!checkNonVirtualMemberCallThisPointer(Info, E, *This, NamedMember))
7322 // Destructor calls are different enough that they have their own codepath.
7323 if (auto *DD = dyn_cast<CXXDestructorDecl>(FD)) {
7324 assert(This && "no 'this' pointer for destructor call");
7325 return HandleDestruction(Info, E, *This,
7326 Info.Ctx.getRecordType(DD->getParent()));
7329 const FunctionDecl *Definition = nullptr;
7330 Stmt *Body = FD->getBody(Definition);
7332 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
7333 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, Info,
7334 Result, ResultSlot))
7337 if (!CovariantAdjustmentPath.empty() &&
7338 !HandleCovariantReturnAdjustment(Info, E, Result,
7339 CovariantAdjustmentPath))
7345 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
7346 return StmtVisitorTy::Visit(E->getInitializer());
7348 bool VisitInitListExpr(const InitListExpr *E) {
7349 if (E->getNumInits() == 0)
7350 return DerivedZeroInitialization(E);
7351 if (E->getNumInits() == 1)
7352 return StmtVisitorTy::Visit(E->getInit(0));
7355 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
7356 return DerivedZeroInitialization(E);
7358 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
7359 return DerivedZeroInitialization(E);
7361 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
7362 return DerivedZeroInitialization(E);
7365 /// A member expression where the object is a prvalue is itself a prvalue.
7366 bool VisitMemberExpr(const MemberExpr *E) {
7367 assert(!Info.Ctx.getLangOpts().CPlusPlus11 &&
7368 "missing temporary materialization conversion");
7369 assert(!E->isArrow() && "missing call to bound member function?");
7372 if (!Evaluate(Val, Info, E->getBase()))
7375 QualType BaseTy = E->getBase()->getType();
7377 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
7378 if (!FD) return Error(E);
7379 assert(!FD->getType()->isReferenceType() && "prvalue reference?");
7380 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
7381 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
7383 // Note: there is no lvalue base here. But this case should only ever
7384 // happen in C or in C++98, where we cannot be evaluating a constexpr
7385 // constructor, which is the only case the base matters.
7386 CompleteObject Obj(APValue::LValueBase(), &Val, BaseTy);
7387 SubobjectDesignator Designator(BaseTy);
7388 Designator.addDeclUnchecked(FD);
7391 return extractSubobject(Info, E, Obj, Designator, Result) &&
7392 DerivedSuccess(Result, E);
7395 bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E) {
7397 if (!Evaluate(Val, Info, E->getBase()))
7400 if (Val.isVector()) {
7401 SmallVector<uint32_t, 4> Indices;
7402 E->getEncodedElementAccess(Indices);
7403 if (Indices.size() == 1) {
7405 return DerivedSuccess(Val.getVectorElt(Indices[0]), E);
7407 // Construct new APValue vector.
7408 SmallVector<APValue, 4> Elts;
7409 for (unsigned I = 0; I < Indices.size(); ++I) {
7410 Elts.push_back(Val.getVectorElt(Indices[I]));
7412 APValue VecResult(Elts.data(), Indices.size());
7413 return DerivedSuccess(VecResult, E);
7420 bool VisitCastExpr(const CastExpr *E) {
7421 switch (E->getCastKind()) {
7425 case CK_AtomicToNonAtomic: {
7427 // This does not need to be done in place even for class/array types:
7428 // atomic-to-non-atomic conversion implies copying the object
7430 if (!Evaluate(AtomicVal, Info, E->getSubExpr()))
7432 return DerivedSuccess(AtomicVal, E);
7436 case CK_UserDefinedConversion:
7437 return StmtVisitorTy::Visit(E->getSubExpr());
7439 case CK_LValueToRValue: {
7441 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
7444 // Note, we use the subexpression's type in order to retain cv-qualifiers.
7445 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
7448 return DerivedSuccess(RVal, E);
7450 case CK_LValueToRValueBitCast: {
7451 APValue DestValue, SourceValue;
7452 if (!Evaluate(SourceValue, Info, E->getSubExpr()))
7454 if (!handleLValueToRValueBitCast(Info, DestValue, SourceValue, E))
7456 return DerivedSuccess(DestValue, E);
7459 case CK_AddressSpaceConversion: {
7461 if (!Evaluate(Value, Info, E->getSubExpr()))
7463 return DerivedSuccess(Value, E);
7470 bool VisitUnaryPostInc(const UnaryOperator *UO) {
7471 return VisitUnaryPostIncDec(UO);
7473 bool VisitUnaryPostDec(const UnaryOperator *UO) {
7474 return VisitUnaryPostIncDec(UO);
7476 bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
7477 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
7481 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info))
7484 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
7485 UO->isIncrementOp(), &RVal))
7487 return DerivedSuccess(RVal, UO);
7490 bool VisitStmtExpr(const StmtExpr *E) {
7491 // We will have checked the full-expressions inside the statement expression
7492 // when they were completed, and don't need to check them again now.
7493 if (Info.checkingForUndefinedBehavior())
7496 const CompoundStmt *CS = E->getSubStmt();
7497 if (CS->body_empty())
7500 BlockScopeRAII Scope(Info);
7501 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
7502 BE = CS->body_end();
7505 const Expr *FinalExpr = dyn_cast<Expr>(*BI);
7507 Info.FFDiag((*BI)->getBeginLoc(),
7508 diag::note_constexpr_stmt_expr_unsupported);
7511 return this->Visit(FinalExpr) && Scope.destroy();
7514 APValue ReturnValue;
7515 StmtResult Result = { ReturnValue, nullptr };
7516 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
7517 if (ESR != ESR_Succeeded) {
7518 // FIXME: If the statement-expression terminated due to 'return',
7519 // 'break', or 'continue', it would be nice to propagate that to
7520 // the outer statement evaluation rather than bailing out.
7521 if (ESR != ESR_Failed)
7522 Info.FFDiag((*BI)->getBeginLoc(),
7523 diag::note_constexpr_stmt_expr_unsupported);
7528 llvm_unreachable("Return from function from the loop above.");
7531 /// Visit a value which is evaluated, but whose value is ignored.
7532 void VisitIgnoredValue(const Expr *E) {
7533 EvaluateIgnoredValue(Info, E);
7536 /// Potentially visit a MemberExpr's base expression.
7537 void VisitIgnoredBaseExpression(const Expr *E) {
7538 // While MSVC doesn't evaluate the base expression, it does diagnose the
7539 // presence of side-effecting behavior.
7540 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
7542 VisitIgnoredValue(E);
7548 //===----------------------------------------------------------------------===//
7549 // Common base class for lvalue and temporary evaluation.
7550 //===----------------------------------------------------------------------===//
7552 template<class Derived>
7553 class LValueExprEvaluatorBase
7554 : public ExprEvaluatorBase<Derived> {
7558 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
7559 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
7561 bool Success(APValue::LValueBase B) {
7566 bool evaluatePointer(const Expr *E, LValue &Result) {
7567 return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
7571 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
7572 : ExprEvaluatorBaseTy(Info), Result(Result),
7573 InvalidBaseOK(InvalidBaseOK) {}
7575 bool Success(const APValue &V, const Expr *E) {
7576 Result.setFrom(this->Info.Ctx, V);
7580 bool VisitMemberExpr(const MemberExpr *E) {
7581 // Handle non-static data members.
7585 EvalOK = evaluatePointer(E->getBase(), Result);
7586 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
7587 } else if (E->getBase()->isRValue()) {
7588 assert(E->getBase()->getType()->isRecordType());
7589 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
7590 BaseTy = E->getBase()->getType();
7592 EvalOK = this->Visit(E->getBase());
7593 BaseTy = E->getBase()->getType();
7598 Result.setInvalid(E);
7602 const ValueDecl *MD = E->getMemberDecl();
7603 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
7604 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
7605 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
7607 if (!HandleLValueMember(this->Info, E, Result, FD))
7609 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
7610 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
7613 return this->Error(E);
7615 if (MD->getType()->isReferenceType()) {
7617 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
7620 return Success(RefValue, E);
7625 bool VisitBinaryOperator(const BinaryOperator *E) {
7626 switch (E->getOpcode()) {
7628 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
7632 return HandleMemberPointerAccess(this->Info, E, Result);
7636 bool VisitCastExpr(const CastExpr *E) {
7637 switch (E->getCastKind()) {
7639 return ExprEvaluatorBaseTy::VisitCastExpr(E);
7641 case CK_DerivedToBase:
7642 case CK_UncheckedDerivedToBase:
7643 if (!this->Visit(E->getSubExpr()))
7646 // Now figure out the necessary offset to add to the base LV to get from
7647 // the derived class to the base class.
7648 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
7655 //===----------------------------------------------------------------------===//
7656 // LValue Evaluation
7658 // This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
7659 // function designators (in C), decl references to void objects (in C), and
7660 // temporaries (if building with -Wno-address-of-temporary).
7662 // LValue evaluation produces values comprising a base expression of one of the
7668 // * CompoundLiteralExpr in C (and in global scope in C++)
7671 // * ObjCStringLiteralExpr
7675 // * CallExpr for a MakeStringConstant builtin
7676 // - typeid(T) expressions, as TypeInfoLValues
7677 // - Locals and temporaries
7678 // * MaterializeTemporaryExpr
7679 // * Any Expr, with a CallIndex indicating the function in which the temporary
7680 // was evaluated, for cases where the MaterializeTemporaryExpr is missing
7681 // from the AST (FIXME).
7682 // * A MaterializeTemporaryExpr that has static storage duration, with no
7683 // CallIndex, for a lifetime-extended temporary.
7684 // * The ConstantExpr that is currently being evaluated during evaluation of an
7685 // immediate invocation.
7686 // plus an offset in bytes.
7687 //===----------------------------------------------------------------------===//
7689 class LValueExprEvaluator
7690 : public LValueExprEvaluatorBase<LValueExprEvaluator> {
7692 LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
7693 LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}
7695 bool VisitVarDecl(const Expr *E, const VarDecl *VD);
7696 bool VisitUnaryPreIncDec(const UnaryOperator *UO);
7698 bool VisitDeclRefExpr(const DeclRefExpr *E);
7699 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
7700 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
7701 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
7702 bool VisitMemberExpr(const MemberExpr *E);
7703 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
7704 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
7705 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
7706 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
7707 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
7708 bool VisitUnaryDeref(const UnaryOperator *E);
7709 bool VisitUnaryReal(const UnaryOperator *E);
7710 bool VisitUnaryImag(const UnaryOperator *E);
7711 bool VisitUnaryPreInc(const UnaryOperator *UO) {
7712 return VisitUnaryPreIncDec(UO);
7714 bool VisitUnaryPreDec(const UnaryOperator *UO) {
7715 return VisitUnaryPreIncDec(UO);
7717 bool VisitBinAssign(const BinaryOperator *BO);
7718 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
7720 bool VisitCastExpr(const CastExpr *E) {
7721 switch (E->getCastKind()) {
7723 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
7725 case CK_LValueBitCast:
7726 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
7727 if (!Visit(E->getSubExpr()))
7729 Result.Designator.setInvalid();
7732 case CK_BaseToDerived:
7733 if (!Visit(E->getSubExpr()))
7735 return HandleBaseToDerivedCast(Info, E, Result);
7738 if (!Visit(E->getSubExpr()))
7740 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result);
7744 } // end anonymous namespace
7746 /// Evaluate an expression as an lvalue. This can be legitimately called on
7747 /// expressions which are not glvalues, in three cases:
7748 /// * function designators in C, and
7749 /// * "extern void" objects
7750 /// * @selector() expressions in Objective-C
7751 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
7752 bool InvalidBaseOK) {
7753 assert(E->isGLValue() || E->getType()->isFunctionType() ||
7754 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E));
7755 return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
7758 bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
7759 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl()))
7761 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
7762 return VisitVarDecl(E, VD);
7763 if (const BindingDecl *BD = dyn_cast<BindingDecl>(E->getDecl()))
7764 return Visit(BD->getBinding());
7765 if (const MSGuidDecl *GD = dyn_cast<MSGuidDecl>(E->getDecl()))
7771 bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
7773 // If we are within a lambda's call operator, check whether the 'VD' referred
7774 // to within 'E' actually represents a lambda-capture that maps to a
7775 // data-member/field within the closure object, and if so, evaluate to the
7776 // field or what the field refers to.
7777 if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee) &&
7778 isa<DeclRefExpr>(E) &&
7779 cast<DeclRefExpr>(E)->refersToEnclosingVariableOrCapture()) {
7780 // We don't always have a complete capture-map when checking or inferring if
7781 // the function call operator meets the requirements of a constexpr function
7782 // - but we don't need to evaluate the captures to determine constexprness
7783 // (dcl.constexpr C++17).
7784 if (Info.checkingPotentialConstantExpression())
7787 if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) {
7788 // Start with 'Result' referring to the complete closure object...
7789 Result = *Info.CurrentCall->This;
7790 // ... then update it to refer to the field of the closure object
7791 // that represents the capture.
7792 if (!HandleLValueMember(Info, E, Result, FD))
7794 // And if the field is of reference type, update 'Result' to refer to what
7795 // the field refers to.
7796 if (FD->getType()->isReferenceType()) {
7798 if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result,
7801 Result.setFrom(Info.Ctx, RVal);
7806 CallStackFrame *Frame = nullptr;
7807 if (VD->hasLocalStorage() && Info.CurrentCall->Index > 1) {
7808 // Only if a local variable was declared in the function currently being
7809 // evaluated, do we expect to be able to find its value in the current
7810 // frame. (Otherwise it was likely declared in an enclosing context and
7811 // could either have a valid evaluatable value (for e.g. a constexpr
7812 // variable) or be ill-formed (and trigger an appropriate evaluation
7814 if (Info.CurrentCall->Callee &&
7815 Info.CurrentCall->Callee->Equals(VD->getDeclContext())) {
7816 Frame = Info.CurrentCall;
7820 if (!VD->getType()->isReferenceType()) {
7822 Result.set({VD, Frame->Index,
7823 Info.CurrentCall->getCurrentTemporaryVersion(VD)});
7830 if (!evaluateVarDeclInit(Info, E, VD, Frame, V, nullptr))
7832 if (!V->hasValue()) {
7833 // FIXME: Is it possible for V to be indeterminate here? If so, we should
7834 // adjust the diagnostic to say that.
7835 if (!Info.checkingPotentialConstantExpression())
7836 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
7839 return Success(*V, E);
7842 bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
7843 const MaterializeTemporaryExpr *E) {
7844 // Walk through the expression to find the materialized temporary itself.
7845 SmallVector<const Expr *, 2> CommaLHSs;
7846 SmallVector<SubobjectAdjustment, 2> Adjustments;
7848 E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
7850 // If we passed any comma operators, evaluate their LHSs.
7851 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
7852 if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
7855 // A materialized temporary with static storage duration can appear within the
7856 // result of a constant expression evaluation, so we need to preserve its
7857 // value for use outside this evaluation.
7859 if (E->getStorageDuration() == SD_Static) {
7860 Value = E->getOrCreateValue(true);
7864 Value = &Info.CurrentCall->createTemporary(
7865 E, E->getType(), E->getStorageDuration() == SD_Automatic, Result);
7868 QualType Type = Inner->getType();
7870 // Materialize the temporary itself.
7871 if (!EvaluateInPlace(*Value, Info, Result, Inner)) {
7876 // Adjust our lvalue to refer to the desired subobject.
7877 for (unsigned I = Adjustments.size(); I != 0; /**/) {
7879 switch (Adjustments[I].Kind) {
7880 case SubobjectAdjustment::DerivedToBaseAdjustment:
7881 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath,
7884 Type = Adjustments[I].DerivedToBase.BasePath->getType();
7887 case SubobjectAdjustment::FieldAdjustment:
7888 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
7890 Type = Adjustments[I].Field->getType();
7893 case SubobjectAdjustment::MemberPointerAdjustment:
7894 if (!HandleMemberPointerAccess(this->Info, Type, Result,
7895 Adjustments[I].Ptr.RHS))
7897 Type = Adjustments[I].Ptr.MPT->getPointeeType();
7906 LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
7907 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
7908 "lvalue compound literal in c++?");
7909 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
7910 // only see this when folding in C, so there's no standard to follow here.
7914 bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
7915 TypeInfoLValue TypeInfo;
7917 if (!E->isPotentiallyEvaluated()) {
7918 if (E->isTypeOperand())
7919 TypeInfo = TypeInfoLValue(E->getTypeOperand(Info.Ctx).getTypePtr());
7921 TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr());
7923 if (!Info.Ctx.getLangOpts().CPlusPlus20) {
7924 Info.CCEDiag(E, diag::note_constexpr_typeid_polymorphic)
7925 << E->getExprOperand()->getType()
7926 << E->getExprOperand()->getSourceRange();
7929 if (!Visit(E->getExprOperand()))
7932 Optional<DynamicType> DynType =
7933 ComputeDynamicType(Info, E, Result, AK_TypeId);
7938 TypeInfoLValue(Info.Ctx.getRecordType(DynType->Type).getTypePtr());
7941 return Success(APValue::LValueBase::getTypeInfo(TypeInfo, E->getType()));
7944 bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
7945 return Success(E->getGuidDecl());
7948 bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
7949 // Handle static data members.
7950 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
7951 VisitIgnoredBaseExpression(E->getBase());
7952 return VisitVarDecl(E, VD);
7955 // Handle static member functions.
7956 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
7957 if (MD->isStatic()) {
7958 VisitIgnoredBaseExpression(E->getBase());
7963 // Handle non-static data members.
7964 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
7967 bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
7968 // FIXME: Deal with vectors as array subscript bases.
7969 if (E->getBase()->getType()->isVectorType())
7972 bool Success = true;
7973 if (!evaluatePointer(E->getBase(), Result)) {
7974 if (!Info.noteFailure())
7980 if (!EvaluateInteger(E->getIdx(), Index, Info))
7984 HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index);
7987 bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
7988 return evaluatePointer(E->getSubExpr(), Result);
7991 bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
7992 if (!Visit(E->getSubExpr()))
7994 // __real is a no-op on scalar lvalues.
7995 if (E->getSubExpr()->getType()->isAnyComplexType())
7996 HandleLValueComplexElement(Info, E, Result, E->getType(), false);
8000 bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
8001 assert(E->getSubExpr()->getType()->isAnyComplexType() &&
8002 "lvalue __imag__ on scalar?");
8003 if (!Visit(E->getSubExpr()))
8005 HandleLValueComplexElement(Info, E, Result, E->getType(), true);
8009 bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
8010 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8013 if (!this->Visit(UO->getSubExpr()))
8016 return handleIncDec(
8017 this->Info, UO, Result, UO->getSubExpr()->getType(),
8018 UO->isIncrementOp(), nullptr);
8021 bool LValueExprEvaluator::VisitCompoundAssignOperator(
8022 const CompoundAssignOperator *CAO) {
8023 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8028 // The overall lvalue result is the result of evaluating the LHS.
8029 if (!this->Visit(CAO->getLHS())) {
8030 if (Info.noteFailure())
8031 Evaluate(RHS, this->Info, CAO->getRHS());
8035 if (!Evaluate(RHS, this->Info, CAO->getRHS()))
8038 return handleCompoundAssignment(
8040 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
8041 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS);
8044 bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
8045 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8050 if (!this->Visit(E->getLHS())) {
8051 if (Info.noteFailure())
8052 Evaluate(NewVal, this->Info, E->getRHS());
8056 if (!Evaluate(NewVal, this->Info, E->getRHS()))
8059 if (Info.getLangOpts().CPlusPlus20 &&
8060 !HandleUnionActiveMemberChange(Info, E->getLHS(), Result))
8063 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
8067 //===----------------------------------------------------------------------===//
8068 // Pointer Evaluation
8069 //===----------------------------------------------------------------------===//
8071 /// Attempts to compute the number of bytes available at the pointer
8072 /// returned by a function with the alloc_size attribute. Returns true if we
8073 /// were successful. Places an unsigned number into `Result`.
8075 /// This expects the given CallExpr to be a call to a function with an
8076 /// alloc_size attribute.
8077 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
8078 const CallExpr *Call,
8079 llvm::APInt &Result) {
8080 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
8082 assert(AllocSize && AllocSize->getElemSizeParam().isValid());
8083 unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex();
8084 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
8085 if (Call->getNumArgs() <= SizeArgNo)
8088 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
8089 Expr::EvalResult ExprResult;
8090 if (!E->EvaluateAsInt(ExprResult, Ctx, Expr::SE_AllowSideEffects))
8092 Into = ExprResult.Val.getInt();
8093 if (Into.isNegative() || !Into.isIntN(BitsInSizeT))
8095 Into = Into.zextOrSelf(BitsInSizeT);
8100 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
8103 if (!AllocSize->getNumElemsParam().isValid()) {
8104 Result = std::move(SizeOfElem);
8108 APSInt NumberOfElems;
8109 unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex();
8110 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
8114 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow);
8118 Result = std::move(BytesAvailable);
8122 /// Convenience function. LVal's base must be a call to an alloc_size
8124 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
8126 llvm::APInt &Result) {
8127 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
8128 "Can't get the size of a non alloc_size function");
8129 const auto *Base = LVal.getLValueBase().get<const Expr *>();
8130 const CallExpr *CE = tryUnwrapAllocSizeCall(Base);
8131 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result);
8134 /// Attempts to evaluate the given LValueBase as the result of a call to
8135 /// a function with the alloc_size attribute. If it was possible to do so, this
8136 /// function will return true, make Result's Base point to said function call,
8137 /// and mark Result's Base as invalid.
8138 static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
8143 // Because we do no form of static analysis, we only support const variables.
8145 // Additionally, we can't support parameters, nor can we support static
8146 // variables (in the latter case, use-before-assign isn't UB; in the former,
8147 // we have no clue what they'll be assigned to).
8149 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>());
8150 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
8153 const Expr *Init = VD->getAnyInitializer();
8157 const Expr *E = Init->IgnoreParens();
8158 if (!tryUnwrapAllocSizeCall(E))
8161 // Store E instead of E unwrapped so that the type of the LValue's base is
8162 // what the user wanted.
8163 Result.setInvalid(E);
8165 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
8166 Result.addUnsizedArray(Info, E, Pointee);
8171 class PointerExprEvaluator
8172 : public ExprEvaluatorBase<PointerExprEvaluator> {
8176 bool Success(const Expr *E) {
8181 bool evaluateLValue(const Expr *E, LValue &Result) {
8182 return EvaluateLValue(E, Result, Info, InvalidBaseOK);
8185 bool evaluatePointer(const Expr *E, LValue &Result) {
8186 return EvaluatePointer(E, Result, Info, InvalidBaseOK);
8189 bool visitNonBuiltinCallExpr(const CallExpr *E);
8192 PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
8193 : ExprEvaluatorBaseTy(info), Result(Result),
8194 InvalidBaseOK(InvalidBaseOK) {}
8196 bool Success(const APValue &V, const Expr *E) {
8197 Result.setFrom(Info.Ctx, V);
8200 bool ZeroInitialization(const Expr *E) {
8201 Result.setNull(Info.Ctx, E->getType());
8205 bool VisitBinaryOperator(const BinaryOperator *E);
8206 bool VisitCastExpr(const CastExpr* E);
8207 bool VisitUnaryAddrOf(const UnaryOperator *E);
8208 bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
8209 { return Success(E); }
8210 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
8211 if (E->isExpressibleAsConstantInitializer())
8213 if (Info.noteFailure())
8214 EvaluateIgnoredValue(Info, E->getSubExpr());
8217 bool VisitAddrLabelExpr(const AddrLabelExpr *E)
8218 { return Success(E); }
8219 bool VisitCallExpr(const CallExpr *E);
8220 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
8221 bool VisitBlockExpr(const BlockExpr *E) {
8222 if (!E->getBlockDecl()->hasCaptures())
8226 bool VisitCXXThisExpr(const CXXThisExpr *E) {
8227 // Can't look at 'this' when checking a potential constant expression.
8228 if (Info.checkingPotentialConstantExpression())
8230 if (!Info.CurrentCall->This) {
8231 if (Info.getLangOpts().CPlusPlus11)
8232 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
8237 Result = *Info.CurrentCall->This;
8238 // If we are inside a lambda's call operator, the 'this' expression refers
8239 // to the enclosing '*this' object (either by value or reference) which is
8240 // either copied into the closure object's field that represents the '*this'
8241 // or refers to '*this'.
8242 if (isLambdaCallOperator(Info.CurrentCall->Callee)) {
8243 // Ensure we actually have captured 'this'. (an error will have
8244 // been previously reported if not).
8245 if (!Info.CurrentCall->LambdaThisCaptureField)
8248 // Update 'Result' to refer to the data member/field of the closure object
8249 // that represents the '*this' capture.
8250 if (!HandleLValueMember(Info, E, Result,
8251 Info.CurrentCall->LambdaThisCaptureField))
8253 // If we captured '*this' by reference, replace the field with its referent.
8254 if (Info.CurrentCall->LambdaThisCaptureField->getType()
8255 ->isPointerType()) {
8257 if (!handleLValueToRValueConversion(Info, E, E->getType(), Result,
8261 Result.setFrom(Info.Ctx, RVal);
8267 bool VisitCXXNewExpr(const CXXNewExpr *E);
8269 bool VisitSourceLocExpr(const SourceLocExpr *E) {
8270 assert(E->isStringType() && "SourceLocExpr isn't a pointer type?");
8271 APValue LValResult = E->EvaluateInContext(
8272 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
8273 Result.setFrom(Info.Ctx, LValResult);
8277 // FIXME: Missing: @protocol, @selector
8279 } // end anonymous namespace
8281 static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
8282 bool InvalidBaseOK) {
8283 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
8284 return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
8287 bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
8288 if (E->getOpcode() != BO_Add &&
8289 E->getOpcode() != BO_Sub)
8290 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8292 const Expr *PExp = E->getLHS();
8293 const Expr *IExp = E->getRHS();
8294 if (IExp->getType()->isPointerType())
8295 std::swap(PExp, IExp);
8297 bool EvalPtrOK = evaluatePointer(PExp, Result);
8298 if (!EvalPtrOK && !Info.noteFailure())
8301 llvm::APSInt Offset;
8302 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
8305 if (E->getOpcode() == BO_Sub)
8306 negateAsSigned(Offset);
8308 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
8309 return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset);
8312 bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
8313 return evaluateLValue(E->getSubExpr(), Result);
8316 bool PointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
8317 const Expr *SubExpr = E->getSubExpr();
8319 switch (E->getCastKind()) {
8323 case CK_CPointerToObjCPointerCast:
8324 case CK_BlockPointerToObjCPointerCast:
8325 case CK_AnyPointerToBlockPointerCast:
8326 case CK_AddressSpaceConversion:
8327 if (!Visit(SubExpr))
8329 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
8330 // permitted in constant expressions in C++11. Bitcasts from cv void* are
8331 // also static_casts, but we disallow them as a resolution to DR1312.
8332 if (!E->getType()->isVoidPointerType()) {
8333 if (!Result.InvalidBase && !Result.Designator.Invalid &&
8334 !Result.IsNullPtr &&
8335 Info.Ctx.hasSameUnqualifiedType(Result.Designator.getType(Info.Ctx),
8336 E->getType()->getPointeeType()) &&
8337 Info.getStdAllocatorCaller("allocate")) {
8338 // Inside a call to std::allocator::allocate and friends, we permit
8339 // casting from void* back to cv1 T* for a pointer that points to a
8342 Result.Designator.setInvalid();
8343 if (SubExpr->getType()->isVoidPointerType())
8344 CCEDiag(E, diag::note_constexpr_invalid_cast)
8345 << 3 << SubExpr->getType();
8347 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8350 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
8351 ZeroInitialization(E);
8354 case CK_DerivedToBase:
8355 case CK_UncheckedDerivedToBase:
8356 if (!evaluatePointer(E->getSubExpr(), Result))
8358 if (!Result.Base && Result.Offset.isZero())
8361 // Now figure out the necessary offset to add to the base LV to get from
8362 // the derived class to the base class.
8363 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()->
8364 castAs<PointerType>()->getPointeeType(),
8367 case CK_BaseToDerived:
8368 if (!Visit(E->getSubExpr()))
8370 if (!Result.Base && Result.Offset.isZero())
8372 return HandleBaseToDerivedCast(Info, E, Result);
8375 if (!Visit(E->getSubExpr()))
8377 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result);
8379 case CK_NullToPointer:
8380 VisitIgnoredValue(E->getSubExpr());
8381 return ZeroInitialization(E);
8383 case CK_IntegralToPointer: {
8384 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8387 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
8390 if (Value.isInt()) {
8391 unsigned Size = Info.Ctx.getTypeSize(E->getType());
8392 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
8393 Result.Base = (Expr*)nullptr;
8394 Result.InvalidBase = false;
8395 Result.Offset = CharUnits::fromQuantity(N);
8396 Result.Designator.setInvalid();
8397 Result.IsNullPtr = false;
8400 // Cast is of an lvalue, no need to change value.
8401 Result.setFrom(Info.Ctx, Value);
8406 case CK_ArrayToPointerDecay: {
8407 if (SubExpr->isGLValue()) {
8408 if (!evaluateLValue(SubExpr, Result))
8411 APValue &Value = Info.CurrentCall->createTemporary(
8412 SubExpr, SubExpr->getType(), false, Result);
8413 if (!EvaluateInPlace(Value, Info, Result, SubExpr))
8416 // The result is a pointer to the first element of the array.
8417 auto *AT = Info.Ctx.getAsArrayType(SubExpr->getType());
8418 if (auto *CAT = dyn_cast<ConstantArrayType>(AT))
8419 Result.addArray(Info, E, CAT);
8421 Result.addUnsizedArray(Info, E, AT->getElementType());
8425 case CK_FunctionToPointerDecay:
8426 return evaluateLValue(SubExpr, Result);
8428 case CK_LValueToRValue: {
8430 if (!evaluateLValue(E->getSubExpr(), LVal))
8434 // Note, we use the subexpression's type in order to retain cv-qualifiers.
8435 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
8437 return InvalidBaseOK &&
8438 evaluateLValueAsAllocSize(Info, LVal.Base, Result);
8439 return Success(RVal, E);
8443 return ExprEvaluatorBaseTy::VisitCastExpr(E);
8446 static CharUnits GetAlignOfType(EvalInfo &Info, QualType T,
8447 UnaryExprOrTypeTrait ExprKind) {
8448 // C++ [expr.alignof]p3:
8449 // When alignof is applied to a reference type, the result is the
8450 // alignment of the referenced type.
8451 if (const ReferenceType *Ref = T->getAs<ReferenceType>())
8452 T = Ref->getPointeeType();
8454 if (T.getQualifiers().hasUnaligned())
8455 return CharUnits::One();
8457 const bool AlignOfReturnsPreferred =
8458 Info.Ctx.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver7;
8460 // __alignof is defined to return the preferred alignment.
8461 // Before 8, clang returned the preferred alignment for alignof and _Alignof
8463 if (ExprKind == UETT_PreferredAlignOf || AlignOfReturnsPreferred)
8464 return Info.Ctx.toCharUnitsFromBits(
8465 Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
8466 // alignof and _Alignof are defined to return the ABI alignment.
8467 else if (ExprKind == UETT_AlignOf)
8468 return Info.Ctx.getTypeAlignInChars(T.getTypePtr());
8470 llvm_unreachable("GetAlignOfType on a non-alignment ExprKind");
8473 static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E,
8474 UnaryExprOrTypeTrait ExprKind) {
8475 E = E->IgnoreParens();
8477 // The kinds of expressions that we have special-case logic here for
8478 // should be kept up to date with the special checks for those
8479 // expressions in Sema.
8481 // alignof decl is always accepted, even if it doesn't make sense: we default
8482 // to 1 in those cases.
8483 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
8484 return Info.Ctx.getDeclAlign(DRE->getDecl(),
8485 /*RefAsPointee*/true);
8487 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
8488 return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
8489 /*RefAsPointee*/true);
8491 return GetAlignOfType(Info, E->getType(), ExprKind);
8494 static CharUnits getBaseAlignment(EvalInfo &Info, const LValue &Value) {
8495 if (const auto *VD = Value.Base.dyn_cast<const ValueDecl *>())
8496 return Info.Ctx.getDeclAlign(VD);
8497 if (const auto *E = Value.Base.dyn_cast<const Expr *>())
8498 return GetAlignOfExpr(Info, E, UETT_AlignOf);
8499 return GetAlignOfType(Info, Value.Base.getTypeInfoType(), UETT_AlignOf);
8502 /// Evaluate the value of the alignment argument to __builtin_align_{up,down},
8503 /// __builtin_is_aligned and __builtin_assume_aligned.
8504 static bool getAlignmentArgument(const Expr *E, QualType ForType,
8505 EvalInfo &Info, APSInt &Alignment) {
8506 if (!EvaluateInteger(E, Alignment, Info))
8508 if (Alignment < 0 || !Alignment.isPowerOf2()) {
8509 Info.FFDiag(E, diag::note_constexpr_invalid_alignment) << Alignment;
8512 unsigned SrcWidth = Info.Ctx.getIntWidth(ForType);
8513 APSInt MaxValue(APInt::getOneBitSet(SrcWidth, SrcWidth - 1));
8514 if (APSInt::compareValues(Alignment, MaxValue) > 0) {
8515 Info.FFDiag(E, diag::note_constexpr_alignment_too_big)
8516 << MaxValue << ForType << Alignment;
8519 // Ensure both alignment and source value have the same bit width so that we
8520 // don't assert when computing the resulting value.
8521 APSInt ExtAlignment =
8522 APSInt(Alignment.zextOrTrunc(SrcWidth), /*isUnsigned=*/true);
8523 assert(APSInt::compareValues(Alignment, ExtAlignment) == 0 &&
8524 "Alignment should not be changed by ext/trunc");
8525 Alignment = ExtAlignment;
8526 assert(Alignment.getBitWidth() == SrcWidth);
8530 // To be clear: this happily visits unsupported builtins. Better name welcomed.
8531 bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
8532 if (ExprEvaluatorBaseTy::VisitCallExpr(E))
8535 if (!(InvalidBaseOK && getAllocSizeAttr(E)))
8538 Result.setInvalid(E);
8539 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
8540 Result.addUnsizedArray(Info, E, PointeeTy);
8544 bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
8545 if (IsStringLiteralCall(E))
8548 if (unsigned BuiltinOp = E->getBuiltinCallee())
8549 return VisitBuiltinCallExpr(E, BuiltinOp);
8551 return visitNonBuiltinCallExpr(E);
8554 // Determine if T is a character type for which we guarantee that
8556 static bool isOneByteCharacterType(QualType T) {
8557 return T->isCharType() || T->isChar8Type();
8560 bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
8561 unsigned BuiltinOp) {
8562 switch (BuiltinOp) {
8563 case Builtin::BI__builtin_addressof:
8564 return evaluateLValue(E->getArg(0), Result);
8565 case Builtin::BI__builtin_assume_aligned: {
8566 // We need to be very careful here because: if the pointer does not have the
8567 // asserted alignment, then the behavior is undefined, and undefined
8568 // behavior is non-constant.
8569 if (!evaluatePointer(E->getArg(0), Result))
8572 LValue OffsetResult(Result);
8574 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info,
8577 CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue());
8579 if (E->getNumArgs() > 2) {
8581 if (!EvaluateInteger(E->getArg(2), Offset, Info))
8584 int64_t AdditionalOffset = -Offset.getZExtValue();
8585 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
8588 // If there is a base object, then it must have the correct alignment.
8589 if (OffsetResult.Base) {
8590 CharUnits BaseAlignment = getBaseAlignment(Info, OffsetResult);
8592 if (BaseAlignment < Align) {
8593 Result.Designator.setInvalid();
8594 // FIXME: Add support to Diagnostic for long / long long.
8595 CCEDiag(E->getArg(0),
8596 diag::note_constexpr_baa_insufficient_alignment) << 0
8597 << (unsigned)BaseAlignment.getQuantity()
8598 << (unsigned)Align.getQuantity();
8603 // The offset must also have the correct alignment.
8604 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
8605 Result.Designator.setInvalid();
8608 ? CCEDiag(E->getArg(0),
8609 diag::note_constexpr_baa_insufficient_alignment) << 1
8610 : CCEDiag(E->getArg(0),
8611 diag::note_constexpr_baa_value_insufficient_alignment))
8612 << (int)OffsetResult.Offset.getQuantity()
8613 << (unsigned)Align.getQuantity();
8619 case Builtin::BI__builtin_align_up:
8620 case Builtin::BI__builtin_align_down: {
8621 if (!evaluatePointer(E->getArg(0), Result))
8624 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info,
8627 CharUnits BaseAlignment = getBaseAlignment(Info, Result);
8628 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Result.Offset);
8629 // For align_up/align_down, we can return the same value if the alignment
8630 // is known to be greater or equal to the requested value.
8631 if (PtrAlign.getQuantity() >= Alignment)
8634 // The alignment could be greater than the minimum at run-time, so we cannot
8635 // infer much about the resulting pointer value. One case is possible:
8636 // For `_Alignas(32) char buf[N]; __builtin_align_down(&buf[idx], 32)` we
8637 // can infer the correct index if the requested alignment is smaller than
8638 // the base alignment so we can perform the computation on the offset.
8639 if (BaseAlignment.getQuantity() >= Alignment) {
8640 assert(Alignment.getBitWidth() <= 64 &&
8641 "Cannot handle > 64-bit address-space");
8642 uint64_t Alignment64 = Alignment.getZExtValue();
8643 CharUnits NewOffset = CharUnits::fromQuantity(
8644 BuiltinOp == Builtin::BI__builtin_align_down
8645 ? llvm::alignDown(Result.Offset.getQuantity(), Alignment64)
8646 : llvm::alignTo(Result.Offset.getQuantity(), Alignment64));
8647 Result.adjustOffset(NewOffset - Result.Offset);
8648 // TODO: diagnose out-of-bounds values/only allow for arrays?
8651 // Otherwise, we cannot constant-evaluate the result.
8652 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_adjust)
8656 case Builtin::BI__builtin_operator_new:
8657 return HandleOperatorNewCall(Info, E, Result);
8658 case Builtin::BI__builtin_launder:
8659 return evaluatePointer(E->getArg(0), Result);
8660 case Builtin::BIstrchr:
8661 case Builtin::BIwcschr:
8662 case Builtin::BImemchr:
8663 case Builtin::BIwmemchr:
8664 if (Info.getLangOpts().CPlusPlus11)
8665 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
8666 << /*isConstexpr*/0 << /*isConstructor*/0
8667 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
8669 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
8671 case Builtin::BI__builtin_strchr:
8672 case Builtin::BI__builtin_wcschr:
8673 case Builtin::BI__builtin_memchr:
8674 case Builtin::BI__builtin_char_memchr:
8675 case Builtin::BI__builtin_wmemchr: {
8676 if (!Visit(E->getArg(0)))
8679 if (!EvaluateInteger(E->getArg(1), Desired, Info))
8681 uint64_t MaxLength = uint64_t(-1);
8682 if (BuiltinOp != Builtin::BIstrchr &&
8683 BuiltinOp != Builtin::BIwcschr &&
8684 BuiltinOp != Builtin::BI__builtin_strchr &&
8685 BuiltinOp != Builtin::BI__builtin_wcschr) {
8687 if (!EvaluateInteger(E->getArg(2), N, Info))
8689 MaxLength = N.getExtValue();
8691 // We cannot find the value if there are no candidates to match against.
8692 if (MaxLength == 0u)
8693 return ZeroInitialization(E);
8694 if (!Result.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
8695 Result.Designator.Invalid)
8697 QualType CharTy = Result.Designator.getType(Info.Ctx);
8698 bool IsRawByte = BuiltinOp == Builtin::BImemchr ||
8699 BuiltinOp == Builtin::BI__builtin_memchr;
8701 Info.Ctx.hasSameUnqualifiedType(
8702 CharTy, E->getArg(0)->getType()->getPointeeType()));
8703 // Pointers to const void may point to objects of incomplete type.
8704 if (IsRawByte && CharTy->isIncompleteType()) {
8705 Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << CharTy;
8708 // Give up on byte-oriented matching against multibyte elements.
8709 // FIXME: We can compare the bytes in the correct order.
8710 if (IsRawByte && !isOneByteCharacterType(CharTy)) {
8711 Info.FFDiag(E, diag::note_constexpr_memchr_unsupported)
8712 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
8716 // Figure out what value we're actually looking for (after converting to
8717 // the corresponding unsigned type if necessary).
8718 uint64_t DesiredVal;
8719 bool StopAtNull = false;
8720 switch (BuiltinOp) {
8721 case Builtin::BIstrchr:
8722 case Builtin::BI__builtin_strchr:
8723 // strchr compares directly to the passed integer, and therefore
8724 // always fails if given an int that is not a char.
8725 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy,
8726 E->getArg(1)->getType(),
8729 return ZeroInitialization(E);
8732 case Builtin::BImemchr:
8733 case Builtin::BI__builtin_memchr:
8734 case Builtin::BI__builtin_char_memchr:
8735 // memchr compares by converting both sides to unsigned char. That's also
8736 // correct for strchr if we get this far (to cope with plain char being
8737 // unsigned in the strchr case).
8738 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue();
8741 case Builtin::BIwcschr:
8742 case Builtin::BI__builtin_wcschr:
8745 case Builtin::BIwmemchr:
8746 case Builtin::BI__builtin_wmemchr:
8747 // wcschr and wmemchr are given a wchar_t to look for. Just use it.
8748 DesiredVal = Desired.getZExtValue();
8752 for (; MaxLength; --MaxLength) {
8754 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
8757 if (Char.getInt().getZExtValue() == DesiredVal)
8759 if (StopAtNull && !Char.getInt())
8761 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
8764 // Not found: return nullptr.
8765 return ZeroInitialization(E);
8768 case Builtin::BImemcpy:
8769 case Builtin::BImemmove:
8770 case Builtin::BIwmemcpy:
8771 case Builtin::BIwmemmove:
8772 if (Info.getLangOpts().CPlusPlus11)
8773 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
8774 << /*isConstexpr*/0 << /*isConstructor*/0
8775 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
8777 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
8779 case Builtin::BI__builtin_memcpy:
8780 case Builtin::BI__builtin_memmove:
8781 case Builtin::BI__builtin_wmemcpy:
8782 case Builtin::BI__builtin_wmemmove: {
8783 bool WChar = BuiltinOp == Builtin::BIwmemcpy ||
8784 BuiltinOp == Builtin::BIwmemmove ||
8785 BuiltinOp == Builtin::BI__builtin_wmemcpy ||
8786 BuiltinOp == Builtin::BI__builtin_wmemmove;
8787 bool Move = BuiltinOp == Builtin::BImemmove ||
8788 BuiltinOp == Builtin::BIwmemmove ||
8789 BuiltinOp == Builtin::BI__builtin_memmove ||
8790 BuiltinOp == Builtin::BI__builtin_wmemmove;
8792 // The result of mem* is the first argument.
8793 if (!Visit(E->getArg(0)))
8795 LValue Dest = Result;
8798 if (!EvaluatePointer(E->getArg(1), Src, Info))
8802 if (!EvaluateInteger(E->getArg(2), N, Info))
8804 assert(!N.isSigned() && "memcpy and friends take an unsigned size");
8806 // If the size is zero, we treat this as always being a valid no-op.
8807 // (Even if one of the src and dest pointers is null.)
8811 // Otherwise, if either of the operands is null, we can't proceed. Don't
8812 // try to determine the type of the copied objects, because there aren't
8814 if (!Src.Base || !Dest.Base) {
8816 (!Src.Base ? Src : Dest).moveInto(Val);
8817 Info.FFDiag(E, diag::note_constexpr_memcpy_null)
8818 << Move << WChar << !!Src.Base
8819 << Val.getAsString(Info.Ctx, E->getArg(0)->getType());
8822 if (Src.Designator.Invalid || Dest.Designator.Invalid)
8825 // We require that Src and Dest are both pointers to arrays of
8826 // trivially-copyable type. (For the wide version, the designator will be
8827 // invalid if the designated object is not a wchar_t.)
8828 QualType T = Dest.Designator.getType(Info.Ctx);
8829 QualType SrcT = Src.Designator.getType(Info.Ctx);
8830 if (!Info.Ctx.hasSameUnqualifiedType(T, SrcT)) {
8831 // FIXME: Consider using our bit_cast implementation to support this.
8832 Info.FFDiag(E, diag::note_constexpr_memcpy_type_pun) << Move << SrcT << T;
8835 if (T->isIncompleteType()) {
8836 Info.FFDiag(E, diag::note_constexpr_memcpy_incomplete_type) << Move << T;
8839 if (!T.isTriviallyCopyableType(Info.Ctx)) {
8840 Info.FFDiag(E, diag::note_constexpr_memcpy_nontrivial) << Move << T;
8844 // Figure out how many T's we're copying.
8845 uint64_t TSize = Info.Ctx.getTypeSizeInChars(T).getQuantity();
8848 llvm::APInt OrigN = N;
8849 llvm::APInt::udivrem(OrigN, TSize, N, Remainder);
8851 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
8852 << Move << WChar << 0 << T << OrigN.toString(10, /*Signed*/false)
8858 // Check that the copying will remain within the arrays, just so that we
8859 // can give a more meaningful diagnostic. This implicitly also checks that
8860 // N fits into 64 bits.
8861 uint64_t RemainingSrcSize = Src.Designator.validIndexAdjustments().second;
8862 uint64_t RemainingDestSize = Dest.Designator.validIndexAdjustments().second;
8863 if (N.ugt(RemainingSrcSize) || N.ugt(RemainingDestSize)) {
8864 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
8865 << Move << WChar << (N.ugt(RemainingSrcSize) ? 1 : 2) << T
8866 << N.toString(10, /*Signed*/false);
8869 uint64_t NElems = N.getZExtValue();
8870 uint64_t NBytes = NElems * TSize;
8872 // Check for overlap.
8874 if (HasSameBase(Src, Dest)) {
8875 uint64_t SrcOffset = Src.getLValueOffset().getQuantity();
8876 uint64_t DestOffset = Dest.getLValueOffset().getQuantity();
8877 if (DestOffset >= SrcOffset && DestOffset - SrcOffset < NBytes) {
8878 // Dest is inside the source region.
8880 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
8883 // For memmove and friends, copy backwards.
8884 if (!HandleLValueArrayAdjustment(Info, E, Src, T, NElems - 1) ||
8885 !HandleLValueArrayAdjustment(Info, E, Dest, T, NElems - 1))
8888 } else if (!Move && SrcOffset >= DestOffset &&
8889 SrcOffset - DestOffset < NBytes) {
8890 // Src is inside the destination region for memcpy: invalid.
8891 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
8898 // FIXME: Set WantObjectRepresentation to true if we're copying a
8900 if (!handleLValueToRValueConversion(Info, E, T, Src, Val) ||
8901 !handleAssignment(Info, E, Dest, T, Val))
8903 // Do not iterate past the last element; if we're copying backwards, that
8904 // might take us off the start of the array.
8907 if (!HandleLValueArrayAdjustment(Info, E, Src, T, Direction) ||
8908 !HandleLValueArrayAdjustment(Info, E, Dest, T, Direction))
8917 return visitNonBuiltinCallExpr(E);
8920 static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
8921 APValue &Result, const InitListExpr *ILE,
8922 QualType AllocType);
8923 static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
8925 const CXXConstructExpr *CCE,
8926 QualType AllocType);
8928 bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) {
8929 if (!Info.getLangOpts().CPlusPlus20)
8930 Info.CCEDiag(E, diag::note_constexpr_new);
8932 // We cannot speculatively evaluate a delete expression.
8933 if (Info.SpeculativeEvaluationDepth)
8936 FunctionDecl *OperatorNew = E->getOperatorNew();
8938 bool IsNothrow = false;
8939 bool IsPlacement = false;
8940 if (OperatorNew->isReservedGlobalPlacementOperator() &&
8941 Info.CurrentCall->isStdFunction() && !E->isArray()) {
8942 // FIXME Support array placement new.
8943 assert(E->getNumPlacementArgs() == 1);
8944 if (!EvaluatePointer(E->getPlacementArg(0), Result, Info))
8946 if (Result.Designator.Invalid)
8949 } else if (!OperatorNew->isReplaceableGlobalAllocationFunction()) {
8950 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
8951 << isa<CXXMethodDecl>(OperatorNew) << OperatorNew;
8953 } else if (E->getNumPlacementArgs()) {
8954 // The only new-placement list we support is of the form (std::nothrow).
8956 // FIXME: There is no restriction on this, but it's not clear that any
8957 // other form makes any sense. We get here for cases such as:
8959 // new (std::align_val_t{N}) X(int)
8961 // (which should presumably be valid only if N is a multiple of
8962 // alignof(int), and in any case can't be deallocated unless N is
8963 // alignof(X) and X has new-extended alignment).
8964 if (E->getNumPlacementArgs() != 1 ||
8965 !E->getPlacementArg(0)->getType()->isNothrowT())
8966 return Error(E, diag::note_constexpr_new_placement);
8969 if (!EvaluateLValue(E->getPlacementArg(0), Nothrow, Info))
8974 const Expr *Init = E->getInitializer();
8975 const InitListExpr *ResizedArrayILE = nullptr;
8976 const CXXConstructExpr *ResizedArrayCCE = nullptr;
8978 QualType AllocType = E->getAllocatedType();
8979 if (Optional<const Expr*> ArraySize = E->getArraySize()) {
8980 const Expr *Stripped = *ArraySize;
8981 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Stripped);
8982 Stripped = ICE->getSubExpr())
8983 if (ICE->getCastKind() != CK_NoOp &&
8984 ICE->getCastKind() != CK_IntegralCast)
8987 llvm::APSInt ArrayBound;
8988 if (!EvaluateInteger(Stripped, ArrayBound, Info))
8991 // C++ [expr.new]p9:
8992 // The expression is erroneous if:
8993 // -- [...] its value before converting to size_t [or] applying the
8994 // second standard conversion sequence is less than zero
8995 if (ArrayBound.isSigned() && ArrayBound.isNegative()) {
8997 return ZeroInitialization(E);
8999 Info.FFDiag(*ArraySize, diag::note_constexpr_new_negative)
9000 << ArrayBound << (*ArraySize)->getSourceRange();
9004 // -- its value is such that the size of the allocated object would
9005 // exceed the implementation-defined limit
9006 if (ConstantArrayType::getNumAddressingBits(Info.Ctx, AllocType,
9008 ConstantArrayType::getMaxSizeBits(Info.Ctx)) {
9010 return ZeroInitialization(E);
9012 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_large)
9013 << ArrayBound << (*ArraySize)->getSourceRange();
9017 // -- the new-initializer is a braced-init-list and the number of
9018 // array elements for which initializers are provided [...]
9019 // exceeds the number of elements to initialize
9020 if (Init && !isa<CXXConstructExpr>(Init)) {
9021 auto *CAT = Info.Ctx.getAsConstantArrayType(Init->getType());
9022 assert(CAT && "unexpected type for array initializer");
9025 std::max(CAT->getSize().getBitWidth(), ArrayBound.getBitWidth());
9026 llvm::APInt InitBound = CAT->getSize().zextOrSelf(Bits);
9027 llvm::APInt AllocBound = ArrayBound.zextOrSelf(Bits);
9028 if (InitBound.ugt(AllocBound)) {
9030 return ZeroInitialization(E);
9032 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_small)
9033 << AllocBound.toString(10, /*Signed=*/false)
9034 << InitBound.toString(10, /*Signed=*/false)
9035 << (*ArraySize)->getSourceRange();
9039 // If the sizes differ, we must have an initializer list, and we need
9040 // special handling for this case when we initialize.
9041 if (InitBound != AllocBound)
9042 ResizedArrayILE = cast<InitListExpr>(Init);
9044 ResizedArrayCCE = cast<CXXConstructExpr>(Init);
9047 AllocType = Info.Ctx.getConstantArrayType(AllocType, ArrayBound, nullptr,
9048 ArrayType::Normal, 0);
9050 assert(!AllocType->isArrayType() &&
9051 "array allocation with non-array new");
9056 AccessKinds AK = AK_Construct;
9057 struct FindObjectHandler {
9061 const AccessKinds AccessKind;
9064 typedef bool result_type;
9065 bool failed() { return false; }
9066 bool found(APValue &Subobj, QualType SubobjType) {
9067 // FIXME: Reject the cases where [basic.life]p8 would not permit the
9068 // old name of the object to be used to name the new object.
9069 if (!Info.Ctx.hasSameUnqualifiedType(SubobjType, AllocType)) {
9070 Info.FFDiag(E, diag::note_constexpr_placement_new_wrong_type) <<
9071 SubobjType << AllocType;
9077 bool found(APSInt &Value, QualType SubobjType) {
9078 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
9081 bool found(APFloat &Value, QualType SubobjType) {
9082 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
9085 } Handler = {Info, E, AllocType, AK, nullptr};
9087 CompleteObject Obj = findCompleteObject(Info, E, AK, Result, AllocType);
9088 if (!Obj || !findSubobject(Info, E, Obj, Result.Designator, Handler))
9091 Val = Handler.Value;
9094 // The lifetime of an object o of type T ends when [...] the storage
9095 // which the object occupies is [...] reused by an object that is not
9096 // nested within o (6.6.2).
9099 // Perform the allocation and obtain a pointer to the resulting object.
9100 Val = Info.createHeapAlloc(E, AllocType, Result);
9105 if (ResizedArrayILE) {
9106 if (!EvaluateArrayNewInitList(Info, Result, *Val, ResizedArrayILE,
9109 } else if (ResizedArrayCCE) {
9110 if (!EvaluateArrayNewConstructExpr(Info, Result, *Val, ResizedArrayCCE,
9114 if (!EvaluateInPlace(*Val, Info, Result, Init))
9116 } else if (!getDefaultInitValue(AllocType, *Val)) {
9120 // Array new returns a pointer to the first element, not a pointer to the
9122 if (auto *AT = AllocType->getAsArrayTypeUnsafe())
9123 Result.addArray(Info, E, cast<ConstantArrayType>(AT));
9127 //===----------------------------------------------------------------------===//
9128 // Member Pointer Evaluation
9129 //===----------------------------------------------------------------------===//
9132 class MemberPointerExprEvaluator
9133 : public ExprEvaluatorBase<MemberPointerExprEvaluator> {
9136 bool Success(const ValueDecl *D) {
9137 Result = MemberPtr(D);
9142 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
9143 : ExprEvaluatorBaseTy(Info), Result(Result) {}
9145 bool Success(const APValue &V, const Expr *E) {
9149 bool ZeroInitialization(const Expr *E) {
9150 return Success((const ValueDecl*)nullptr);
9153 bool VisitCastExpr(const CastExpr *E);
9154 bool VisitUnaryAddrOf(const UnaryOperator *E);
9156 } // end anonymous namespace
9158 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
9160 assert(E->isRValue() && E->getType()->isMemberPointerType());
9161 return MemberPointerExprEvaluator(Info, Result).Visit(E);
9164 bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
9165 switch (E->getCastKind()) {
9167 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9169 case CK_NullToMemberPointer:
9170 VisitIgnoredValue(E->getSubExpr());
9171 return ZeroInitialization(E);
9173 case CK_BaseToDerivedMemberPointer: {
9174 if (!Visit(E->getSubExpr()))
9176 if (E->path_empty())
9178 // Base-to-derived member pointer casts store the path in derived-to-base
9179 // order, so iterate backwards. The CXXBaseSpecifier also provides us with
9180 // the wrong end of the derived->base arc, so stagger the path by one class.
9181 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
9182 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
9183 PathI != PathE; ++PathI) {
9184 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
9185 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
9186 if (!Result.castToDerived(Derived))
9189 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
9190 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
9195 case CK_DerivedToBaseMemberPointer:
9196 if (!Visit(E->getSubExpr()))
9198 for (CastExpr::path_const_iterator PathI = E->path_begin(),
9199 PathE = E->path_end(); PathI != PathE; ++PathI) {
9200 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
9201 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
9202 if (!Result.castToBase(Base))
9209 bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
9210 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
9211 // member can be formed.
9212 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
9215 //===----------------------------------------------------------------------===//
9216 // Record Evaluation
9217 //===----------------------------------------------------------------------===//
9220 class RecordExprEvaluator
9221 : public ExprEvaluatorBase<RecordExprEvaluator> {
9226 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
9227 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
9229 bool Success(const APValue &V, const Expr *E) {
9233 bool ZeroInitialization(const Expr *E) {
9234 return ZeroInitialization(E, E->getType());
9236 bool ZeroInitialization(const Expr *E, QualType T);
9238 bool VisitCallExpr(const CallExpr *E) {
9239 return handleCallExpr(E, Result, &This);
9241 bool VisitCastExpr(const CastExpr *E);
9242 bool VisitInitListExpr(const InitListExpr *E);
9243 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
9244 return VisitCXXConstructExpr(E, E->getType());
9246 bool VisitLambdaExpr(const LambdaExpr *E);
9247 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
9248 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
9249 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
9250 bool VisitBinCmp(const BinaryOperator *E);
9254 /// Perform zero-initialization on an object of non-union class type.
9255 /// C++11 [dcl.init]p5:
9256 /// To zero-initialize an object or reference of type T means:
9258 /// -- if T is a (possibly cv-qualified) non-union class type,
9259 /// each non-static data member and each base-class subobject is
9260 /// zero-initialized
9261 static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
9262 const RecordDecl *RD,
9263 const LValue &This, APValue &Result) {
9264 assert(!RD->isUnion() && "Expected non-union class type");
9265 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
9266 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
9267 std::distance(RD->field_begin(), RD->field_end()));
9269 if (RD->isInvalidDecl()) return false;
9270 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
9274 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
9275 End = CD->bases_end(); I != End; ++I, ++Index) {
9276 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
9277 LValue Subobject = This;
9278 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout))
9280 if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
9281 Result.getStructBase(Index)))
9286 for (const auto *I : RD->fields()) {
9287 // -- if T is a reference type, no initialization is performed.
9288 if (I->getType()->isReferenceType())
9291 LValue Subobject = This;
9292 if (!HandleLValueMember(Info, E, Subobject, I, &Layout))
9295 ImplicitValueInitExpr VIE(I->getType());
9296 if (!EvaluateInPlace(
9297 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE))
9304 bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
9305 const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
9306 if (RD->isInvalidDecl()) return false;
9307 if (RD->isUnion()) {
9308 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
9309 // object's first non-static named data member is zero-initialized
9310 RecordDecl::field_iterator I = RD->field_begin();
9311 if (I == RD->field_end()) {
9312 Result = APValue((const FieldDecl*)nullptr);
9316 LValue Subobject = This;
9317 if (!HandleLValueMember(Info, E, Subobject, *I))
9319 Result = APValue(*I);
9320 ImplicitValueInitExpr VIE(I->getType());
9321 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
9324 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
9325 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
9329 return HandleClassZeroInitialization(Info, E, RD, This, Result);
9332 bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
9333 switch (E->getCastKind()) {
9335 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9337 case CK_ConstructorConversion:
9338 return Visit(E->getSubExpr());
9340 case CK_DerivedToBase:
9341 case CK_UncheckedDerivedToBase: {
9342 APValue DerivedObject;
9343 if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
9345 if (!DerivedObject.isStruct())
9346 return Error(E->getSubExpr());
9348 // Derived-to-base rvalue conversion: just slice off the derived part.
9349 APValue *Value = &DerivedObject;
9350 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
9351 for (CastExpr::path_const_iterator PathI = E->path_begin(),
9352 PathE = E->path_end(); PathI != PathE; ++PathI) {
9353 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base");
9354 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
9355 Value = &Value->getStructBase(getBaseIndex(RD, Base));
9364 bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
9365 if (E->isTransparent())
9366 return Visit(E->getInit(0));
9368 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
9369 if (RD->isInvalidDecl()) return false;
9370 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
9371 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
9373 EvalInfo::EvaluatingConstructorRAII EvalObj(
9375 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
9376 CXXRD && CXXRD->getNumBases());
9378 if (RD->isUnion()) {
9379 const FieldDecl *Field = E->getInitializedFieldInUnion();
9380 Result = APValue(Field);
9384 // If the initializer list for a union does not contain any elements, the
9385 // first element of the union is value-initialized.
9386 // FIXME: The element should be initialized from an initializer list.
9387 // Is this difference ever observable for initializer lists which
9389 ImplicitValueInitExpr VIE(Field->getType());
9390 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;
9392 LValue Subobject = This;
9393 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout))
9396 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
9397 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
9398 isa<CXXDefaultInitExpr>(InitExpr));
9400 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr);
9403 if (!Result.hasValue())
9404 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
9405 std::distance(RD->field_begin(), RD->field_end()));
9406 unsigned ElementNo = 0;
9407 bool Success = true;
9409 // Initialize base classes.
9410 if (CXXRD && CXXRD->getNumBases()) {
9411 for (const auto &Base : CXXRD->bases()) {
9412 assert(ElementNo < E->getNumInits() && "missing init for base class");
9413 const Expr *Init = E->getInit(ElementNo);
9415 LValue Subobject = This;
9416 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base))
9419 APValue &FieldVal = Result.getStructBase(ElementNo);
9420 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) {
9421 if (!Info.noteFailure())
9428 EvalObj.finishedConstructingBases();
9431 // Initialize members.
9432 for (const auto *Field : RD->fields()) {
9433 // Anonymous bit-fields are not considered members of the class for
9434 // purposes of aggregate initialization.
9435 if (Field->isUnnamedBitfield())
9438 LValue Subobject = This;
9440 bool HaveInit = ElementNo < E->getNumInits();
9442 // FIXME: Diagnostics here should point to the end of the initializer
9443 // list, not the start.
9444 if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E,
9445 Subobject, Field, &Layout))
9448 // Perform an implicit value-initialization for members beyond the end of
9449 // the initializer list.
9450 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
9451 const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE;
9453 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
9454 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
9455 isa<CXXDefaultInitExpr>(Init));
9457 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
9458 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) ||
9459 (Field->isBitField() && !truncateBitfieldValue(Info, Init,
9460 FieldVal, Field))) {
9461 if (!Info.noteFailure())
9467 EvalObj.finishedConstructingFields();
9472 bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
9474 // Note that E's type is not necessarily the type of our class here; we might
9475 // be initializing an array element instead.
9476 const CXXConstructorDecl *FD = E->getConstructor();
9477 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
9479 bool ZeroInit = E->requiresZeroInitialization();
9480 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
9481 // If we've already performed zero-initialization, we're already done.
9482 if (Result.hasValue())
9486 return ZeroInitialization(E, T);
9488 return getDefaultInitValue(T, Result);
9491 const FunctionDecl *Definition = nullptr;
9492 auto Body = FD->getBody(Definition);
9494 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
9497 // Avoid materializing a temporary for an elidable copy/move constructor.
9498 if (E->isElidable() && !ZeroInit)
9499 if (const MaterializeTemporaryExpr *ME
9500 = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0)))
9501 return Visit(ME->getSubExpr());
9503 if (ZeroInit && !ZeroInitialization(E, T))
9506 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
9507 return HandleConstructorCall(E, This, Args,
9508 cast<CXXConstructorDecl>(Definition), Info,
9512 bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
9513 const CXXInheritedCtorInitExpr *E) {
9514 if (!Info.CurrentCall) {
9515 assert(Info.checkingPotentialConstantExpression());
9519 const CXXConstructorDecl *FD = E->getConstructor();
9520 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
9523 const FunctionDecl *Definition = nullptr;
9524 auto Body = FD->getBody(Definition);
9526 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
9529 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
9530 cast<CXXConstructorDecl>(Definition), Info,
9534 bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
9535 const CXXStdInitializerListExpr *E) {
9536 const ConstantArrayType *ArrayType =
9537 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
9540 if (!EvaluateLValue(E->getSubExpr(), Array, Info))
9543 // Get a pointer to the first element of the array.
9544 Array.addArray(Info, E, ArrayType);
9546 auto InvalidType = [&] {
9547 Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
9552 // FIXME: Perform the checks on the field types in SemaInit.
9553 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
9554 RecordDecl::field_iterator Field = Record->field_begin();
9555 if (Field == Record->field_end())
9556 return InvalidType();
9559 if (!Field->getType()->isPointerType() ||
9560 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
9561 ArrayType->getElementType()))
9562 return InvalidType();
9564 // FIXME: What if the initializer_list type has base classes, etc?
9565 Result = APValue(APValue::UninitStruct(), 0, 2);
9566 Array.moveInto(Result.getStructField(0));
9568 if (++Field == Record->field_end())
9569 return InvalidType();
9571 if (Field->getType()->isPointerType() &&
9572 Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
9573 ArrayType->getElementType())) {
9575 if (!HandleLValueArrayAdjustment(Info, E, Array,
9576 ArrayType->getElementType(),
9577 ArrayType->getSize().getZExtValue()))
9579 Array.moveInto(Result.getStructField(1));
9580 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
9582 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize()));
9584 return InvalidType();
9586 if (++Field != Record->field_end())
9587 return InvalidType();
9592 bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
9593 const CXXRecordDecl *ClosureClass = E->getLambdaClass();
9594 if (ClosureClass->isInvalidDecl())
9597 const size_t NumFields =
9598 std::distance(ClosureClass->field_begin(), ClosureClass->field_end());
9600 assert(NumFields == (size_t)std::distance(E->capture_init_begin(),
9601 E->capture_init_end()) &&
9602 "The number of lambda capture initializers should equal the number of "
9603 "fields within the closure type");
9605 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields);
9606 // Iterate through all the lambda's closure object's fields and initialize
9608 auto *CaptureInitIt = E->capture_init_begin();
9609 const LambdaCapture *CaptureIt = ClosureClass->captures_begin();
9610 bool Success = true;
9611 for (const auto *Field : ClosureClass->fields()) {
9612 assert(CaptureInitIt != E->capture_init_end());
9613 // Get the initializer for this field
9614 Expr *const CurFieldInit = *CaptureInitIt++;
9616 // If there is no initializer, either this is a VLA or an error has
9621 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
9622 if (!EvaluateInPlace(FieldVal, Info, This, CurFieldInit)) {
9623 if (!Info.keepEvaluatingAfterFailure())
9632 static bool EvaluateRecord(const Expr *E, const LValue &This,
9633 APValue &Result, EvalInfo &Info) {
9634 assert(E->isRValue() && E->getType()->isRecordType() &&
9635 "can't evaluate expression as a record rvalue");
9636 return RecordExprEvaluator(Info, This, Result).Visit(E);
9639 //===----------------------------------------------------------------------===//
9640 // Temporary Evaluation
9642 // Temporaries are represented in the AST as rvalues, but generally behave like
9643 // lvalues. The full-object of which the temporary is a subobject is implicitly
9644 // materialized so that a reference can bind to it.
9645 //===----------------------------------------------------------------------===//
9647 class TemporaryExprEvaluator
9648 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
9650 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
9651 LValueExprEvaluatorBaseTy(Info, Result, false) {}
9653 /// Visit an expression which constructs the value of this temporary.
9654 bool VisitConstructExpr(const Expr *E) {
9656 Info.CurrentCall->createTemporary(E, E->getType(), false, Result);
9657 return EvaluateInPlace(Value, Info, Result, E);
9660 bool VisitCastExpr(const CastExpr *E) {
9661 switch (E->getCastKind()) {
9663 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
9665 case CK_ConstructorConversion:
9666 return VisitConstructExpr(E->getSubExpr());
9669 bool VisitInitListExpr(const InitListExpr *E) {
9670 return VisitConstructExpr(E);
9672 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
9673 return VisitConstructExpr(E);
9675 bool VisitCallExpr(const CallExpr *E) {
9676 return VisitConstructExpr(E);
9678 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
9679 return VisitConstructExpr(E);
9681 bool VisitLambdaExpr(const LambdaExpr *E) {
9682 return VisitConstructExpr(E);
9685 } // end anonymous namespace
9687 /// Evaluate an expression of record type as a temporary.
9688 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
9689 assert(E->isRValue() && E->getType()->isRecordType());
9690 return TemporaryExprEvaluator(Info, Result).Visit(E);
9693 //===----------------------------------------------------------------------===//
9694 // Vector Evaluation
9695 //===----------------------------------------------------------------------===//
9698 class VectorExprEvaluator
9699 : public ExprEvaluatorBase<VectorExprEvaluator> {
9703 VectorExprEvaluator(EvalInfo &info, APValue &Result)
9704 : ExprEvaluatorBaseTy(info), Result(Result) {}
9706 bool Success(ArrayRef<APValue> V, const Expr *E) {
9707 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements());
9708 // FIXME: remove this APValue copy.
9709 Result = APValue(V.data(), V.size());
9712 bool Success(const APValue &V, const Expr *E) {
9713 assert(V.isVector());
9717 bool ZeroInitialization(const Expr *E);
9719 bool VisitUnaryReal(const UnaryOperator *E)
9720 { return Visit(E->getSubExpr()); }
9721 bool VisitCastExpr(const CastExpr* E);
9722 bool VisitInitListExpr(const InitListExpr *E);
9723 bool VisitUnaryImag(const UnaryOperator *E);
9724 bool VisitBinaryOperator(const BinaryOperator *E);
9725 // FIXME: Missing: unary -, unary ~, conditional operator (for GNU
9726 // conditional select), shufflevector, ExtVectorElementExpr
9728 } // end anonymous namespace
9730 static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
9731 assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue");
9732 return VectorExprEvaluator(Info, Result).Visit(E);
9735 bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
9736 const VectorType *VTy = E->getType()->castAs<VectorType>();
9737 unsigned NElts = VTy->getNumElements();
9739 const Expr *SE = E->getSubExpr();
9740 QualType SETy = SE->getType();
9742 switch (E->getCastKind()) {
9743 case CK_VectorSplat: {
9744 APValue Val = APValue();
9745 if (SETy->isIntegerType()) {
9747 if (!EvaluateInteger(SE, IntResult, Info))
9749 Val = APValue(std::move(IntResult));
9750 } else if (SETy->isRealFloatingType()) {
9751 APFloat FloatResult(0.0);
9752 if (!EvaluateFloat(SE, FloatResult, Info))
9754 Val = APValue(std::move(FloatResult));
9759 // Splat and create vector APValue.
9760 SmallVector<APValue, 4> Elts(NElts, Val);
9761 return Success(Elts, E);
9764 // Evaluate the operand into an APInt we can extract from.
9765 llvm::APInt SValInt;
9766 if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
9768 // Extract the elements
9769 QualType EltTy = VTy->getElementType();
9770 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
9771 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
9772 SmallVector<APValue, 4> Elts;
9773 if (EltTy->isRealFloatingType()) {
9774 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
9775 unsigned FloatEltSize = EltSize;
9776 if (&Sem == &APFloat::x87DoubleExtended())
9778 for (unsigned i = 0; i < NElts; i++) {
9781 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
9783 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
9784 Elts.push_back(APValue(APFloat(Sem, Elt)));
9786 } else if (EltTy->isIntegerType()) {
9787 for (unsigned i = 0; i < NElts; i++) {
9790 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
9792 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
9793 Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType())));
9798 return Success(Elts, E);
9801 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9806 VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
9807 const VectorType *VT = E->getType()->castAs<VectorType>();
9808 unsigned NumInits = E->getNumInits();
9809 unsigned NumElements = VT->getNumElements();
9811 QualType EltTy = VT->getElementType();
9812 SmallVector<APValue, 4> Elements;
9814 // The number of initializers can be less than the number of
9815 // vector elements. For OpenCL, this can be due to nested vector
9816 // initialization. For GCC compatibility, missing trailing elements
9817 // should be initialized with zeroes.
9818 unsigned CountInits = 0, CountElts = 0;
9819 while (CountElts < NumElements) {
9820 // Handle nested vector initialization.
9821 if (CountInits < NumInits
9822 && E->getInit(CountInits)->getType()->isVectorType()) {
9824 if (!EvaluateVector(E->getInit(CountInits), v, Info))
9826 unsigned vlen = v.getVectorLength();
9827 for (unsigned j = 0; j < vlen; j++)
9828 Elements.push_back(v.getVectorElt(j));
9830 } else if (EltTy->isIntegerType()) {
9831 llvm::APSInt sInt(32);
9832 if (CountInits < NumInits) {
9833 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
9835 } else // trailing integer zero.
9836 sInt = Info.Ctx.MakeIntValue(0, EltTy);
9837 Elements.push_back(APValue(sInt));
9840 llvm::APFloat f(0.0);
9841 if (CountInits < NumInits) {
9842 if (!EvaluateFloat(E->getInit(CountInits), f, Info))
9844 } else // trailing float zero.
9845 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
9846 Elements.push_back(APValue(f));
9851 return Success(Elements, E);
9855 VectorExprEvaluator::ZeroInitialization(const Expr *E) {
9856 const auto *VT = E->getType()->castAs<VectorType>();
9857 QualType EltTy = VT->getElementType();
9858 APValue ZeroElement;
9859 if (EltTy->isIntegerType())
9860 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
9863 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
9865 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
9866 return Success(Elements, E);
9869 bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
9870 VisitIgnoredValue(E->getSubExpr());
9871 return ZeroInitialization(E);
9874 bool VectorExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
9875 BinaryOperatorKind Op = E->getOpcode();
9876 assert(Op != BO_PtrMemD && Op != BO_PtrMemI && Op != BO_Cmp &&
9877 "Operation not supported on vector types");
9880 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
9882 Expr *LHS = E->getLHS();
9883 Expr *RHS = E->getRHS();
9885 assert(LHS->getType()->isVectorType() && RHS->getType()->isVectorType() &&
9886 "Must both be vector types");
9887 // Checking JUST the types are the same would be fine, except shifts don't
9888 // need to have their types be the same (since you always shift by an int).
9889 assert(LHS->getType()->getAs<VectorType>()->getNumElements() ==
9890 E->getType()->getAs<VectorType>()->getNumElements() &&
9891 RHS->getType()->getAs<VectorType>()->getNumElements() ==
9892 E->getType()->getAs<VectorType>()->getNumElements() &&
9893 "All operands must be the same size.");
9897 bool LHSOK = Evaluate(LHSValue, Info, LHS);
9898 if (!LHSOK && !Info.noteFailure())
9900 if (!Evaluate(RHSValue, Info, RHS) || !LHSOK)
9903 if (!handleVectorVectorBinOp(Info, E, Op, LHSValue, RHSValue))
9906 return Success(LHSValue, E);
9909 //===----------------------------------------------------------------------===//
9911 //===----------------------------------------------------------------------===//
9914 class ArrayExprEvaluator
9915 : public ExprEvaluatorBase<ArrayExprEvaluator> {
9920 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
9921 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
9923 bool Success(const APValue &V, const Expr *E) {
9924 assert(V.isArray() && "expected array");
9929 bool ZeroInitialization(const Expr *E) {
9930 const ConstantArrayType *CAT =
9931 Info.Ctx.getAsConstantArrayType(E->getType());
9933 if (E->getType()->isIncompleteArrayType()) {
9934 // We can be asked to zero-initialize a flexible array member; this
9935 // is represented as an ImplicitValueInitExpr of incomplete array
9936 // type. In this case, the array has zero elements.
9937 Result = APValue(APValue::UninitArray(), 0, 0);
9940 // FIXME: We could handle VLAs here.
9944 Result = APValue(APValue::UninitArray(), 0,
9945 CAT->getSize().getZExtValue());
9946 if (!Result.hasArrayFiller()) return true;
9948 // Zero-initialize all elements.
9949 LValue Subobject = This;
9950 Subobject.addArray(Info, E, CAT);
9951 ImplicitValueInitExpr VIE(CAT->getElementType());
9952 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
9955 bool VisitCallExpr(const CallExpr *E) {
9956 return handleCallExpr(E, Result, &This);
9958 bool VisitInitListExpr(const InitListExpr *E,
9959 QualType AllocType = QualType());
9960 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
9961 bool VisitCXXConstructExpr(const CXXConstructExpr *E);
9962 bool VisitCXXConstructExpr(const CXXConstructExpr *E,
9963 const LValue &Subobject,
9964 APValue *Value, QualType Type);
9965 bool VisitStringLiteral(const StringLiteral *E,
9966 QualType AllocType = QualType()) {
9967 expandStringLiteral(Info, E, Result, AllocType);
9971 } // end anonymous namespace
9973 static bool EvaluateArray(const Expr *E, const LValue &This,
9974 APValue &Result, EvalInfo &Info) {
9975 assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue");
9976 return ArrayExprEvaluator(Info, This, Result).Visit(E);
9979 static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
9980 APValue &Result, const InitListExpr *ILE,
9981 QualType AllocType) {
9982 assert(ILE->isRValue() && ILE->getType()->isArrayType() &&
9983 "not an array rvalue");
9984 return ArrayExprEvaluator(Info, This, Result)
9985 .VisitInitListExpr(ILE, AllocType);
9988 static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
9990 const CXXConstructExpr *CCE,
9991 QualType AllocType) {
9992 assert(CCE->isRValue() && CCE->getType()->isArrayType() &&
9993 "not an array rvalue");
9994 return ArrayExprEvaluator(Info, This, Result)
9995 .VisitCXXConstructExpr(CCE, This, &Result, AllocType);
9998 // Return true iff the given array filler may depend on the element index.
9999 static bool MaybeElementDependentArrayFiller(const Expr *FillerExpr) {
10000 // For now, just allow non-class value-initialization and initialization
10001 // lists comprised of them.
10002 if (isa<ImplicitValueInitExpr>(FillerExpr))
10004 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(FillerExpr)) {
10005 for (unsigned I = 0, E = ILE->getNumInits(); I != E; ++I) {
10006 if (MaybeElementDependentArrayFiller(ILE->getInit(I)))
10014 bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E,
10015 QualType AllocType) {
10016 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
10017 AllocType.isNull() ? E->getType() : AllocType);
10021 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
10022 // an appropriately-typed string literal enclosed in braces.
10023 if (E->isStringLiteralInit()) {
10024 auto *SL = dyn_cast<StringLiteral>(E->getInit(0)->IgnoreParens());
10025 // FIXME: Support ObjCEncodeExpr here once we support it in
10026 // ArrayExprEvaluator generally.
10029 return VisitStringLiteral(SL, AllocType);
10032 bool Success = true;
10034 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&
10035 "zero-initialized array shouldn't have any initialized elts");
10037 if (Result.isArray() && Result.hasArrayFiller())
10038 Filler = Result.getArrayFiller();
10040 unsigned NumEltsToInit = E->getNumInits();
10041 unsigned NumElts = CAT->getSize().getZExtValue();
10042 const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr;
10044 // If the initializer might depend on the array index, run it for each
10046 if (NumEltsToInit != NumElts && MaybeElementDependentArrayFiller(FillerExpr))
10047 NumEltsToInit = NumElts;
10049 LLVM_DEBUG(llvm::dbgs() << "The number of elements to initialize: "
10050 << NumEltsToInit << ".\n");
10052 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
10054 // If the array was previously zero-initialized, preserve the
10055 // zero-initialized values.
10056 if (Filler.hasValue()) {
10057 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
10058 Result.getArrayInitializedElt(I) = Filler;
10059 if (Result.hasArrayFiller())
10060 Result.getArrayFiller() = Filler;
10063 LValue Subobject = This;
10064 Subobject.addArray(Info, E, CAT);
10065 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
10067 Index < E->getNumInits() ? E->getInit(Index) : FillerExpr;
10068 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
10069 Info, Subobject, Init) ||
10070 !HandleLValueArrayAdjustment(Info, Init, Subobject,
10071 CAT->getElementType(), 1)) {
10072 if (!Info.noteFailure())
10078 if (!Result.hasArrayFiller())
10081 // If we get here, we have a trivial filler, which we can just evaluate
10082 // once and splat over the rest of the array elements.
10083 assert(FillerExpr && "no array filler for incomplete init list");
10084 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject,
10085 FillerExpr) && Success;
10088 bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
10090 if (E->getCommonExpr() &&
10091 !Evaluate(Info.CurrentCall->createTemporary(
10092 E->getCommonExpr(),
10093 getStorageType(Info.Ctx, E->getCommonExpr()), false,
10095 Info, E->getCommonExpr()->getSourceExpr()))
10098 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());
10100 uint64_t Elements = CAT->getSize().getZExtValue();
10101 Result = APValue(APValue::UninitArray(), Elements, Elements);
10103 LValue Subobject = This;
10104 Subobject.addArray(Info, E, CAT);
10106 bool Success = true;
10107 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
10108 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
10109 Info, Subobject, E->getSubExpr()) ||
10110 !HandleLValueArrayAdjustment(Info, E, Subobject,
10111 CAT->getElementType(), 1)) {
10112 if (!Info.noteFailure())
10121 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
10122 return VisitCXXConstructExpr(E, This, &Result, E->getType());
10125 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
10126 const LValue &Subobject,
10129 bool HadZeroInit = Value->hasValue();
10131 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
10132 unsigned N = CAT->getSize().getZExtValue();
10134 // Preserve the array filler if we had prior zero-initialization.
10136 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
10139 *Value = APValue(APValue::UninitArray(), N, N);
10142 for (unsigned I = 0; I != N; ++I)
10143 Value->getArrayInitializedElt(I) = Filler;
10145 // Initialize the elements.
10146 LValue ArrayElt = Subobject;
10147 ArrayElt.addArray(Info, E, CAT);
10148 for (unsigned I = 0; I != N; ++I)
10149 if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I),
10150 CAT->getElementType()) ||
10151 !HandleLValueArrayAdjustment(Info, E, ArrayElt,
10152 CAT->getElementType(), 1))
10158 if (!Type->isRecordType())
10161 return RecordExprEvaluator(Info, Subobject, *Value)
10162 .VisitCXXConstructExpr(E, Type);
10165 //===----------------------------------------------------------------------===//
10166 // Integer Evaluation
10168 // As a GNU extension, we support casting pointers to sufficiently-wide integer
10169 // types and back in constant folding. Integer values are thus represented
10170 // either as an integer-valued APValue, or as an lvalue-valued APValue.
10171 //===----------------------------------------------------------------------===//
10174 class IntExprEvaluator
10175 : public ExprEvaluatorBase<IntExprEvaluator> {
10178 IntExprEvaluator(EvalInfo &info, APValue &result)
10179 : ExprEvaluatorBaseTy(info), Result(result) {}
10181 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
10182 assert(E->getType()->isIntegralOrEnumerationType() &&
10183 "Invalid evaluation result.");
10184 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
10185 "Invalid evaluation result.");
10186 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
10187 "Invalid evaluation result.");
10188 Result = APValue(SI);
10191 bool Success(const llvm::APSInt &SI, const Expr *E) {
10192 return Success(SI, E, Result);
10195 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
10196 assert(E->getType()->isIntegralOrEnumerationType() &&
10197 "Invalid evaluation result.");
10198 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
10199 "Invalid evaluation result.");
10200 Result = APValue(APSInt(I));
10201 Result.getInt().setIsUnsigned(
10202 E->getType()->isUnsignedIntegerOrEnumerationType());
10205 bool Success(const llvm::APInt &I, const Expr *E) {
10206 return Success(I, E, Result);
10209 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
10210 assert(E->getType()->isIntegralOrEnumerationType() &&
10211 "Invalid evaluation result.");
10212 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
10215 bool Success(uint64_t Value, const Expr *E) {
10216 return Success(Value, E, Result);
10219 bool Success(CharUnits Size, const Expr *E) {
10220 return Success(Size.getQuantity(), E);
10223 bool Success(const APValue &V, const Expr *E) {
10224 if (V.isLValue() || V.isAddrLabelDiff() || V.isIndeterminate()) {
10228 return Success(V.getInt(), E);
10231 bool ZeroInitialization(const Expr *E) { return Success(0, E); }
10233 //===--------------------------------------------------------------------===//
10235 //===--------------------------------------------------------------------===//
10237 bool VisitIntegerLiteral(const IntegerLiteral *E) {
10238 return Success(E->getValue(), E);
10240 bool VisitCharacterLiteral(const CharacterLiteral *E) {
10241 return Success(E->getValue(), E);
10244 bool CheckReferencedDecl(const Expr *E, const Decl *D);
10245 bool VisitDeclRefExpr(const DeclRefExpr *E) {
10246 if (CheckReferencedDecl(E, E->getDecl()))
10249 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
10251 bool VisitMemberExpr(const MemberExpr *E) {
10252 if (CheckReferencedDecl(E, E->getMemberDecl())) {
10253 VisitIgnoredBaseExpression(E->getBase());
10257 return ExprEvaluatorBaseTy::VisitMemberExpr(E);
10260 bool VisitCallExpr(const CallExpr *E);
10261 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
10262 bool VisitBinaryOperator(const BinaryOperator *E);
10263 bool VisitOffsetOfExpr(const OffsetOfExpr *E);
10264 bool VisitUnaryOperator(const UnaryOperator *E);
10266 bool VisitCastExpr(const CastExpr* E);
10267 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
10269 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
10270 return Success(E->getValue(), E);
10273 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
10274 return Success(E->getValue(), E);
10277 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
10278 if (Info.ArrayInitIndex == uint64_t(-1)) {
10279 // We were asked to evaluate this subexpression independent of the
10280 // enclosing ArrayInitLoopExpr. We can't do that.
10284 return Success(Info.ArrayInitIndex, E);
10287 // Note, GNU defines __null as an integer, not a pointer.
10288 bool VisitGNUNullExpr(const GNUNullExpr *E) {
10289 return ZeroInitialization(E);
10292 bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
10293 return Success(E->getValue(), E);
10296 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
10297 return Success(E->getValue(), E);
10300 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
10301 return Success(E->getValue(), E);
10304 bool VisitUnaryReal(const UnaryOperator *E);
10305 bool VisitUnaryImag(const UnaryOperator *E);
10307 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
10308 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
10309 bool VisitSourceLocExpr(const SourceLocExpr *E);
10310 bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E);
10311 bool VisitRequiresExpr(const RequiresExpr *E);
10312 // FIXME: Missing: array subscript of vector, member of vector
10315 class FixedPointExprEvaluator
10316 : public ExprEvaluatorBase<FixedPointExprEvaluator> {
10320 FixedPointExprEvaluator(EvalInfo &info, APValue &result)
10321 : ExprEvaluatorBaseTy(info), Result(result) {}
10323 bool Success(const llvm::APInt &I, const Expr *E) {
10325 APFixedPoint(I, Info.Ctx.getFixedPointSemantics(E->getType())), E);
10328 bool Success(uint64_t Value, const Expr *E) {
10330 APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(E->getType())), E);
10333 bool Success(const APValue &V, const Expr *E) {
10334 return Success(V.getFixedPoint(), E);
10337 bool Success(const APFixedPoint &V, const Expr *E) {
10338 assert(E->getType()->isFixedPointType() && "Invalid evaluation result.");
10339 assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) &&
10340 "Invalid evaluation result.");
10341 Result = APValue(V);
10345 //===--------------------------------------------------------------------===//
10347 //===--------------------------------------------------------------------===//
10349 bool VisitFixedPointLiteral(const FixedPointLiteral *E) {
10350 return Success(E->getValue(), E);
10353 bool VisitCastExpr(const CastExpr *E);
10354 bool VisitUnaryOperator(const UnaryOperator *E);
10355 bool VisitBinaryOperator(const BinaryOperator *E);
10357 } // end anonymous namespace
10359 /// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
10360 /// produce either the integer value or a pointer.
10362 /// GCC has a heinous extension which folds casts between pointer types and
10363 /// pointer-sized integral types. We support this by allowing the evaluation of
10364 /// an integer rvalue to produce a pointer (represented as an lvalue) instead.
10365 /// Some simple arithmetic on such values is supported (they are treated much
10367 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
10369 assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType());
10370 return IntExprEvaluator(Info, Result).Visit(E);
10373 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
10375 if (!EvaluateIntegerOrLValue(E, Val, Info))
10377 if (!Val.isInt()) {
10378 // FIXME: It would be better to produce the diagnostic for casting
10379 // a pointer to an integer.
10380 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
10383 Result = Val.getInt();
10387 bool IntExprEvaluator::VisitSourceLocExpr(const SourceLocExpr *E) {
10388 APValue Evaluated = E->EvaluateInContext(
10389 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
10390 return Success(Evaluated, E);
10393 static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
10395 if (E->getType()->isFixedPointType()) {
10397 if (!FixedPointExprEvaluator(Info, Val).Visit(E))
10399 if (!Val.isFixedPoint())
10402 Result = Val.getFixedPoint();
10408 static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
10410 if (E->getType()->isIntegerType()) {
10411 auto FXSema = Info.Ctx.getFixedPointSemantics(E->getType());
10413 if (!EvaluateInteger(E, Val, Info))
10415 Result = APFixedPoint(Val, FXSema);
10417 } else if (E->getType()->isFixedPointType()) {
10418 return EvaluateFixedPoint(E, Result, Info);
10423 /// Check whether the given declaration can be directly converted to an integral
10424 /// rvalue. If not, no diagnostic is produced; there are other things we can
10426 bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
10427 // Enums are integer constant exprs.
10428 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
10429 // Check for signedness/width mismatches between E type and ECD value.
10430 bool SameSign = (ECD->getInitVal().isSigned()
10431 == E->getType()->isSignedIntegerOrEnumerationType());
10432 bool SameWidth = (ECD->getInitVal().getBitWidth()
10433 == Info.Ctx.getIntWidth(E->getType()));
10434 if (SameSign && SameWidth)
10435 return Success(ECD->getInitVal(), E);
10437 // Get rid of mismatch (otherwise Success assertions will fail)
10438 // by computing a new value matching the type of E.
10439 llvm::APSInt Val = ECD->getInitVal();
10441 Val.setIsSigned(!ECD->getInitVal().isSigned());
10443 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
10444 return Success(Val, E);
10450 /// Values returned by __builtin_classify_type, chosen to match the values
10451 /// produced by GCC's builtin.
10452 enum class GCCTypeClass {
10456 // GCC reserves 2 for character types, but instead classifies them as
10461 // GCC reserves 6 for references, but appears to never use it (because
10462 // expressions never have reference type, presumably).
10463 PointerToDataMember = 7,
10466 // GCC reserves 10 for functions, but does not use it since GCC version 6 due
10467 // to decay to pointer. (Prior to version 6 it was only used in C++ mode).
10468 // GCC claims to reserve 11 for pointers to member functions, but *actually*
10469 // uses 12 for that purpose, same as for a class or struct. Maybe it
10470 // internally implements a pointer to member as a struct? Who knows.
10471 PointerToMemberFunction = 12, // Not a bug, see above.
10472 ClassOrStruct = 12,
10474 // GCC reserves 14 for arrays, but does not use it since GCC version 6 due to
10475 // decay to pointer. (Prior to version 6 it was only used in C++ mode).
10476 // GCC reserves 15 for strings, but actually uses 5 (pointer) for string
10480 /// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
10482 static GCCTypeClass
10483 EvaluateBuiltinClassifyType(QualType T, const LangOptions &LangOpts) {
10484 assert(!T->isDependentType() && "unexpected dependent type");
10486 QualType CanTy = T.getCanonicalType();
10487 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy);
10489 switch (CanTy->getTypeClass()) {
10490 #define TYPE(ID, BASE)
10491 #define DEPENDENT_TYPE(ID, BASE) case Type::ID:
10492 #define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
10493 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
10494 #include "clang/AST/TypeNodes.inc"
10496 case Type::DeducedTemplateSpecialization:
10497 llvm_unreachable("unexpected non-canonical or dependent type");
10499 case Type::Builtin:
10500 switch (BT->getKind()) {
10501 #define BUILTIN_TYPE(ID, SINGLETON_ID)
10502 #define SIGNED_TYPE(ID, SINGLETON_ID) \
10503 case BuiltinType::ID: return GCCTypeClass::Integer;
10504 #define FLOATING_TYPE(ID, SINGLETON_ID) \
10505 case BuiltinType::ID: return GCCTypeClass::RealFloat;
10506 #define PLACEHOLDER_TYPE(ID, SINGLETON_ID) \
10507 case BuiltinType::ID: break;
10508 #include "clang/AST/BuiltinTypes.def"
10509 case BuiltinType::Void:
10510 return GCCTypeClass::Void;
10512 case BuiltinType::Bool:
10513 return GCCTypeClass::Bool;
10515 case BuiltinType::Char_U:
10516 case BuiltinType::UChar:
10517 case BuiltinType::WChar_U:
10518 case BuiltinType::Char8:
10519 case BuiltinType::Char16:
10520 case BuiltinType::Char32:
10521 case BuiltinType::UShort:
10522 case BuiltinType::UInt:
10523 case BuiltinType::ULong:
10524 case BuiltinType::ULongLong:
10525 case BuiltinType::UInt128:
10526 return GCCTypeClass::Integer;
10528 case BuiltinType::UShortAccum:
10529 case BuiltinType::UAccum:
10530 case BuiltinType::ULongAccum:
10531 case BuiltinType::UShortFract:
10532 case BuiltinType::UFract:
10533 case BuiltinType::ULongFract:
10534 case BuiltinType::SatUShortAccum:
10535 case BuiltinType::SatUAccum:
10536 case BuiltinType::SatULongAccum:
10537 case BuiltinType::SatUShortFract:
10538 case BuiltinType::SatUFract:
10539 case BuiltinType::SatULongFract:
10540 return GCCTypeClass::None;
10542 case BuiltinType::NullPtr:
10544 case BuiltinType::ObjCId:
10545 case BuiltinType::ObjCClass:
10546 case BuiltinType::ObjCSel:
10547 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
10548 case BuiltinType::Id:
10549 #include "clang/Basic/OpenCLImageTypes.def"
10550 #define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
10551 case BuiltinType::Id:
10552 #include "clang/Basic/OpenCLExtensionTypes.def"
10553 case BuiltinType::OCLSampler:
10554 case BuiltinType::OCLEvent:
10555 case BuiltinType::OCLClkEvent:
10556 case BuiltinType::OCLQueue:
10557 case BuiltinType::OCLReserveID:
10558 #define SVE_TYPE(Name, Id, SingletonId) \
10559 case BuiltinType::Id:
10560 #include "clang/Basic/AArch64SVEACLETypes.def"
10561 return GCCTypeClass::None;
10563 case BuiltinType::Dependent:
10564 llvm_unreachable("unexpected dependent type");
10566 llvm_unreachable("unexpected placeholder type");
10569 return LangOpts.CPlusPlus ? GCCTypeClass::Enum : GCCTypeClass::Integer;
10571 case Type::Pointer:
10572 case Type::ConstantArray:
10573 case Type::VariableArray:
10574 case Type::IncompleteArray:
10575 case Type::FunctionNoProto:
10576 case Type::FunctionProto:
10577 return GCCTypeClass::Pointer;
10579 case Type::MemberPointer:
10580 return CanTy->isMemberDataPointerType()
10581 ? GCCTypeClass::PointerToDataMember
10582 : GCCTypeClass::PointerToMemberFunction;
10584 case Type::Complex:
10585 return GCCTypeClass::Complex;
10588 return CanTy->isUnionType() ? GCCTypeClass::Union
10589 : GCCTypeClass::ClassOrStruct;
10592 // GCC classifies _Atomic T the same as T.
10593 return EvaluateBuiltinClassifyType(
10594 CanTy->castAs<AtomicType>()->getValueType(), LangOpts);
10596 case Type::BlockPointer:
10598 case Type::ExtVector:
10599 case Type::ConstantMatrix:
10600 case Type::ObjCObject:
10601 case Type::ObjCInterface:
10602 case Type::ObjCObjectPointer:
10605 // GCC classifies vectors as None. We follow its lead and classify all
10606 // other types that don't fit into the regular classification the same way.
10607 return GCCTypeClass::None;
10609 case Type::LValueReference:
10610 case Type::RValueReference:
10611 llvm_unreachable("invalid type for expression");
10614 llvm_unreachable("unexpected type class");
10617 /// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
10619 static GCCTypeClass
10620 EvaluateBuiltinClassifyType(const CallExpr *E, const LangOptions &LangOpts) {
10621 // If no argument was supplied, default to None. This isn't
10622 // ideal, however it is what gcc does.
10623 if (E->getNumArgs() == 0)
10624 return GCCTypeClass::None;
10626 // FIXME: Bizarrely, GCC treats a call with more than one argument as not
10627 // being an ICE, but still folds it to a constant using the type of the first
10629 return EvaluateBuiltinClassifyType(E->getArg(0)->getType(), LangOpts);
10632 /// EvaluateBuiltinConstantPForLValue - Determine the result of
10633 /// __builtin_constant_p when applied to the given pointer.
10635 /// A pointer is only "constant" if it is null (or a pointer cast to integer)
10636 /// or it points to the first character of a string literal.
10637 static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) {
10638 APValue::LValueBase Base = LV.getLValueBase();
10639 if (Base.isNull()) {
10640 // A null base is acceptable.
10642 } else if (const Expr *E = Base.dyn_cast<const Expr *>()) {
10643 if (!isa<StringLiteral>(E))
10645 return LV.getLValueOffset().isZero();
10646 } else if (Base.is<TypeInfoLValue>()) {
10647 // Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to
10648 // evaluate to true.
10651 // Any other base is not constant enough for GCC.
10656 /// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
10657 /// GCC as we can manage.
10658 static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) {
10659 // This evaluation is not permitted to have side-effects, so evaluate it in
10660 // a speculative evaluation context.
10661 SpeculativeEvaluationRAII SpeculativeEval(Info);
10663 // Constant-folding is always enabled for the operand of __builtin_constant_p
10664 // (even when the enclosing evaluation context otherwise requires a strict
10665 // language-specific constant expression).
10666 FoldConstant Fold(Info, true);
10668 QualType ArgType = Arg->getType();
10670 // __builtin_constant_p always has one operand. The rules which gcc follows
10671 // are not precisely documented, but are as follows:
10673 // - If the operand is of integral, floating, complex or enumeration type,
10674 // and can be folded to a known value of that type, it returns 1.
10675 // - If the operand can be folded to a pointer to the first character
10676 // of a string literal (or such a pointer cast to an integral type)
10677 // or to a null pointer or an integer cast to a pointer, it returns 1.
10679 // Otherwise, it returns 0.
10681 // FIXME: GCC also intends to return 1 for literals of aggregate types, but
10682 // its support for this did not work prior to GCC 9 and is not yet well
10684 if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() ||
10685 ArgType->isAnyComplexType() || ArgType->isPointerType() ||
10686 ArgType->isNullPtrType()) {
10688 if (!::EvaluateAsRValue(Info, Arg, V) || Info.EvalStatus.HasSideEffects) {
10689 Fold.keepDiagnostics();
10693 // For a pointer (possibly cast to integer), there are special rules.
10694 if (V.getKind() == APValue::LValue)
10695 return EvaluateBuiltinConstantPForLValue(V);
10697 // Otherwise, any constant value is good enough.
10698 return V.hasValue();
10701 // Anything else isn't considered to be sufficiently constant.
10705 /// Retrieves the "underlying object type" of the given expression,
10706 /// as used by __builtin_object_size.
10707 static QualType getObjectType(APValue::LValueBase B) {
10708 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
10709 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
10710 return VD->getType();
10711 } else if (const Expr *E = B.dyn_cast<const Expr*>()) {
10712 if (isa<CompoundLiteralExpr>(E))
10713 return E->getType();
10714 } else if (B.is<TypeInfoLValue>()) {
10715 return B.getTypeInfoType();
10716 } else if (B.is<DynamicAllocLValue>()) {
10717 return B.getDynamicAllocType();
10723 /// A more selective version of E->IgnoreParenCasts for
10724 /// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
10725 /// to change the type of E.
10726 /// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
10728 /// Always returns an RValue with a pointer representation.
10729 static const Expr *ignorePointerCastsAndParens(const Expr *E) {
10730 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
10732 auto *NoParens = E->IgnoreParens();
10733 auto *Cast = dyn_cast<CastExpr>(NoParens);
10734 if (Cast == nullptr)
10737 // We only conservatively allow a few kinds of casts, because this code is
10738 // inherently a simple solution that seeks to support the common case.
10739 auto CastKind = Cast->getCastKind();
10740 if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
10741 CastKind != CK_AddressSpaceConversion)
10744 auto *SubExpr = Cast->getSubExpr();
10745 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isRValue())
10747 return ignorePointerCastsAndParens(SubExpr);
10750 /// Checks to see if the given LValue's Designator is at the end of the LValue's
10751 /// record layout. e.g.
10752 /// struct { struct { int a, b; } fst, snd; } obj;
10755 /// obj.fst.a // no
10756 /// obj.fst.b // no
10757 /// obj.snd.a // no
10758 /// obj.snd.b // yes
10760 /// Please note: this function is specialized for how __builtin_object_size
10761 /// views "objects".
10763 /// If this encounters an invalid RecordDecl or otherwise cannot determine the
10764 /// correct result, it will always return true.
10765 static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
10766 assert(!LVal.Designator.Invalid);
10768 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
10769 const RecordDecl *Parent = FD->getParent();
10770 Invalid = Parent->isInvalidDecl();
10771 if (Invalid || Parent->isUnion())
10773 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent);
10774 return FD->getFieldIndex() + 1 == Layout.getFieldCount();
10777 auto &Base = LVal.getLValueBase();
10778 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) {
10779 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
10781 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
10783 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) {
10784 for (auto *FD : IFD->chain()) {
10786 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid))
10793 QualType BaseType = getType(Base);
10794 if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
10795 // If we don't know the array bound, conservatively assume we're looking at
10796 // the final array element.
10798 if (BaseType->isIncompleteArrayType())
10799 BaseType = Ctx.getAsArrayType(BaseType)->getElementType();
10801 BaseType = BaseType->castAs<PointerType>()->getPointeeType();
10804 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
10805 const auto &Entry = LVal.Designator.Entries[I];
10806 if (BaseType->isArrayType()) {
10807 // Because __builtin_object_size treats arrays as objects, we can ignore
10808 // the index iff this is the last array in the Designator.
10811 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType));
10812 uint64_t Index = Entry.getAsArrayIndex();
10813 if (Index + 1 != CAT->getSize())
10815 BaseType = CAT->getElementType();
10816 } else if (BaseType->isAnyComplexType()) {
10817 const auto *CT = BaseType->castAs<ComplexType>();
10818 uint64_t Index = Entry.getAsArrayIndex();
10821 BaseType = CT->getElementType();
10822 } else if (auto *FD = getAsField(Entry)) {
10824 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
10826 BaseType = FD->getType();
10828 assert(getAsBaseClass(Entry) && "Expecting cast to a base class");
10835 /// Tests to see if the LValue has a user-specified designator (that isn't
10836 /// necessarily valid). Note that this always returns 'true' if the LValue has
10837 /// an unsized array as its first designator entry, because there's currently no
10838 /// way to tell if the user typed *foo or foo[0].
10839 static bool refersToCompleteObject(const LValue &LVal) {
10840 if (LVal.Designator.Invalid)
10843 if (!LVal.Designator.Entries.empty())
10844 return LVal.Designator.isMostDerivedAnUnsizedArray();
10846 if (!LVal.InvalidBase)
10849 // If `E` is a MemberExpr, then the first part of the designator is hiding in
10851 const auto *E = LVal.Base.dyn_cast<const Expr *>();
10852 return !E || !isa<MemberExpr>(E);
10855 /// Attempts to detect a user writing into a piece of memory that's impossible
10856 /// to figure out the size of by just using types.
10857 static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
10858 const SubobjectDesignator &Designator = LVal.Designator;
10860 // - Users can only write off of the end when we have an invalid base. Invalid
10861 // bases imply we don't know where the memory came from.
10862 // - We used to be a bit more aggressive here; we'd only be conservative if
10863 // the array at the end was flexible, or if it had 0 or 1 elements. This
10864 // broke some common standard library extensions (PR30346), but was
10865 // otherwise seemingly fine. It may be useful to reintroduce this behavior
10866 // with some sort of list. OTOH, it seems that GCC is always
10867 // conservative with the last element in structs (if it's an array), so our
10868 // current behavior is more compatible than an explicit list approach would
10870 return LVal.InvalidBase &&
10871 Designator.Entries.size() == Designator.MostDerivedPathLength &&
10872 Designator.MostDerivedIsArrayElement &&
10873 isDesignatorAtObjectEnd(Ctx, LVal);
10876 /// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
10877 /// Fails if the conversion would cause loss of precision.
10878 static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
10879 CharUnits &Result) {
10880 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
10881 if (Int.ugt(CharUnitsMax))
10883 Result = CharUnits::fromQuantity(Int.getZExtValue());
10887 /// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
10888 /// determine how many bytes exist from the beginning of the object to either
10889 /// the end of the current subobject, or the end of the object itself, depending
10890 /// on what the LValue looks like + the value of Type.
10892 /// If this returns false, the value of Result is undefined.
10893 static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
10894 unsigned Type, const LValue &LVal,
10895 CharUnits &EndOffset) {
10896 bool DetermineForCompleteObject = refersToCompleteObject(LVal);
10898 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
10899 if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
10901 return HandleSizeof(Info, ExprLoc, Ty, Result);
10904 // We want to evaluate the size of the entire object. This is a valid fallback
10905 // for when Type=1 and the designator is invalid, because we're asked for an
10907 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
10908 // Type=3 wants a lower bound, so we can't fall back to this.
10909 if (Type == 3 && !DetermineForCompleteObject)
10912 llvm::APInt APEndOffset;
10913 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
10914 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
10915 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
10917 if (LVal.InvalidBase)
10920 QualType BaseTy = getObjectType(LVal.getLValueBase());
10921 return CheckedHandleSizeof(BaseTy, EndOffset);
10924 // We want to evaluate the size of a subobject.
10925 const SubobjectDesignator &Designator = LVal.Designator;
10927 // The following is a moderately common idiom in C:
10929 // struct Foo { int a; char c[1]; };
10930 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
10931 // strcpy(&F->c[0], Bar);
10933 // In order to not break too much legacy code, we need to support it.
10934 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) {
10935 // If we can resolve this to an alloc_size call, we can hand that back,
10936 // because we know for certain how many bytes there are to write to.
10937 llvm::APInt APEndOffset;
10938 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
10939 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
10940 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
10942 // If we cannot determine the size of the initial allocation, then we can't
10943 // given an accurate upper-bound. However, we are still able to give
10944 // conservative lower-bounds for Type=3.
10949 CharUnits BytesPerElem;
10950 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
10953 // According to the GCC documentation, we want the size of the subobject
10954 // denoted by the pointer. But that's not quite right -- what we actually
10955 // want is the size of the immediately-enclosing array, if there is one.
10956 int64_t ElemsRemaining;
10957 if (Designator.MostDerivedIsArrayElement &&
10958 Designator.Entries.size() == Designator.MostDerivedPathLength) {
10959 uint64_t ArraySize = Designator.getMostDerivedArraySize();
10960 uint64_t ArrayIndex = Designator.Entries.back().getAsArrayIndex();
10961 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
10963 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
10966 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
10970 /// Tries to evaluate the __builtin_object_size for @p E. If successful,
10971 /// returns true and stores the result in @p Size.
10973 /// If @p WasError is non-null, this will report whether the failure to evaluate
10974 /// is to be treated as an Error in IntExprEvaluator.
10975 static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
10976 EvalInfo &Info, uint64_t &Size) {
10977 // Determine the denoted object.
10980 // The operand of __builtin_object_size is never evaluated for side-effects.
10981 // If there are any, but we can determine the pointed-to object anyway, then
10982 // ignore the side-effects.
10983 SpeculativeEvaluationRAII SpeculativeEval(Info);
10984 IgnoreSideEffectsRAII Fold(Info);
10986 if (E->isGLValue()) {
10987 // It's possible for us to be given GLValues if we're called via
10988 // Expr::tryEvaluateObjectSize.
10990 if (!EvaluateAsRValue(Info, E, RVal))
10992 LVal.setFrom(Info.Ctx, RVal);
10993 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info,
10994 /*InvalidBaseOK=*/true))
10998 // If we point to before the start of the object, there are no accessible
11000 if (LVal.getLValueOffset().isNegative()) {
11005 CharUnits EndOffset;
11006 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset))
11009 // If we've fallen outside of the end offset, just pretend there's nothing to
11010 // write to/read from.
11011 if (EndOffset <= LVal.getLValueOffset())
11014 Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
11018 bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
11019 if (unsigned BuiltinOp = E->getBuiltinCallee())
11020 return VisitBuiltinCallExpr(E, BuiltinOp);
11022 return ExprEvaluatorBaseTy::VisitCallExpr(E);
11025 static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info,
11026 APValue &Val, APSInt &Alignment) {
11027 QualType SrcTy = E->getArg(0)->getType();
11028 if (!getAlignmentArgument(E->getArg(1), SrcTy, Info, Alignment))
11030 // Even though we are evaluating integer expressions we could get a pointer
11031 // argument for the __builtin_is_aligned() case.
11032 if (SrcTy->isPointerType()) {
11034 if (!EvaluatePointer(E->getArg(0), Ptr, Info))
11037 } else if (!SrcTy->isIntegralOrEnumerationType()) {
11038 Info.FFDiag(E->getArg(0));
11042 if (!EvaluateInteger(E->getArg(0), SrcInt, Info))
11044 assert(SrcInt.getBitWidth() >= Alignment.getBitWidth() &&
11045 "Bit widths must be the same");
11046 Val = APValue(SrcInt);
11048 assert(Val.hasValue());
11052 bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
11053 unsigned BuiltinOp) {
11054 switch (BuiltinOp) {
11056 return ExprEvaluatorBaseTy::VisitCallExpr(E);
11058 case Builtin::BI__builtin_dynamic_object_size:
11059 case Builtin::BI__builtin_object_size: {
11060 // The type was checked when we built the expression.
11062 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
11063 assert(Type <= 3 && "unexpected type");
11066 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size))
11067 return Success(Size, E);
11069 if (E->getArg(0)->HasSideEffects(Info.Ctx))
11070 return Success((Type & 2) ? 0 : -1, E);
11072 // Expression had no side effects, but we couldn't statically determine the
11073 // size of the referenced object.
11074 switch (Info.EvalMode) {
11075 case EvalInfo::EM_ConstantExpression:
11076 case EvalInfo::EM_ConstantFold:
11077 case EvalInfo::EM_IgnoreSideEffects:
11078 // Leave it to IR generation.
11080 case EvalInfo::EM_ConstantExpressionUnevaluated:
11081 // Reduce it to a constant now.
11082 return Success((Type & 2) ? 0 : -1, E);
11085 llvm_unreachable("unexpected EvalMode");
11088 case Builtin::BI__builtin_os_log_format_buffer_size: {
11089 analyze_os_log::OSLogBufferLayout Layout;
11090 analyze_os_log::computeOSLogBufferLayout(Info.Ctx, E, Layout);
11091 return Success(Layout.size().getQuantity(), E);
11094 case Builtin::BI__builtin_is_aligned: {
11097 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11099 if (Src.isLValue()) {
11100 // If we evaluated a pointer, check the minimum known alignment.
11102 Ptr.setFrom(Info.Ctx, Src);
11103 CharUnits BaseAlignment = getBaseAlignment(Info, Ptr);
11104 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Ptr.Offset);
11105 // We can return true if the known alignment at the computed offset is
11106 // greater than the requested alignment.
11107 assert(PtrAlign.isPowerOfTwo());
11108 assert(Alignment.isPowerOf2());
11109 if (PtrAlign.getQuantity() >= Alignment)
11110 return Success(1, E);
11111 // If the alignment is not known to be sufficient, some cases could still
11112 // be aligned at run time. However, if the requested alignment is less or
11113 // equal to the base alignment and the offset is not aligned, we know that
11114 // the run-time value can never be aligned.
11115 if (BaseAlignment.getQuantity() >= Alignment &&
11116 PtrAlign.getQuantity() < Alignment)
11117 return Success(0, E);
11118 // Otherwise we can't infer whether the value is sufficiently aligned.
11119 // TODO: __builtin_is_aligned(__builtin_align_{down,up{(expr, N), N)
11120 // in cases where we can't fully evaluate the pointer.
11121 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_compute)
11125 assert(Src.isInt());
11126 return Success((Src.getInt() & (Alignment - 1)) == 0 ? 1 : 0, E);
11128 case Builtin::BI__builtin_align_up: {
11131 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11135 APSInt AlignedVal =
11136 APSInt((Src.getInt() + (Alignment - 1)) & ~(Alignment - 1),
11137 Src.getInt().isUnsigned());
11138 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth());
11139 return Success(AlignedVal, E);
11141 case Builtin::BI__builtin_align_down: {
11144 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11148 APSInt AlignedVal =
11149 APSInt(Src.getInt() & ~(Alignment - 1), Src.getInt().isUnsigned());
11150 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth());
11151 return Success(AlignedVal, E);
11154 case Builtin::BI__builtin_bswap16:
11155 case Builtin::BI__builtin_bswap32:
11156 case Builtin::BI__builtin_bswap64: {
11158 if (!EvaluateInteger(E->getArg(0), Val, Info))
11161 return Success(Val.byteSwap(), E);
11164 case Builtin::BI__builtin_classify_type:
11165 return Success((int)EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E);
11167 case Builtin::BI__builtin_clrsb:
11168 case Builtin::BI__builtin_clrsbl:
11169 case Builtin::BI__builtin_clrsbll: {
11171 if (!EvaluateInteger(E->getArg(0), Val, Info))
11174 return Success(Val.getBitWidth() - Val.getMinSignedBits(), E);
11177 case Builtin::BI__builtin_clz:
11178 case Builtin::BI__builtin_clzl:
11179 case Builtin::BI__builtin_clzll:
11180 case Builtin::BI__builtin_clzs: {
11182 if (!EvaluateInteger(E->getArg(0), Val, Info))
11187 return Success(Val.countLeadingZeros(), E);
11190 case Builtin::BI__builtin_constant_p: {
11191 const Expr *Arg = E->getArg(0);
11192 if (EvaluateBuiltinConstantP(Info, Arg))
11193 return Success(true, E);
11194 if (Info.InConstantContext || Arg->HasSideEffects(Info.Ctx)) {
11195 // Outside a constant context, eagerly evaluate to false in the presence
11196 // of side-effects in order to avoid -Wunsequenced false-positives in
11197 // a branch on __builtin_constant_p(expr).
11198 return Success(false, E);
11200 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
11204 case Builtin::BI__builtin_is_constant_evaluated: {
11205 const auto *Callee = Info.CurrentCall->getCallee();
11206 if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression &&
11207 (Info.CallStackDepth == 1 ||
11208 (Info.CallStackDepth == 2 && Callee->isInStdNamespace() &&
11209 Callee->getIdentifier() &&
11210 Callee->getIdentifier()->isStr("is_constant_evaluated")))) {
11211 // FIXME: Find a better way to avoid duplicated diagnostics.
11212 if (Info.EvalStatus.Diag)
11213 Info.report((Info.CallStackDepth == 1) ? E->getExprLoc()
11214 : Info.CurrentCall->CallLoc,
11215 diag::warn_is_constant_evaluated_always_true_constexpr)
11216 << (Info.CallStackDepth == 1 ? "__builtin_is_constant_evaluated"
11217 : "std::is_constant_evaluated");
11220 return Success(Info.InConstantContext, E);
11223 case Builtin::BI__builtin_ctz:
11224 case Builtin::BI__builtin_ctzl:
11225 case Builtin::BI__builtin_ctzll:
11226 case Builtin::BI__builtin_ctzs: {
11228 if (!EvaluateInteger(E->getArg(0), Val, Info))
11233 return Success(Val.countTrailingZeros(), E);
11236 case Builtin::BI__builtin_eh_return_data_regno: {
11237 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
11238 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
11239 return Success(Operand, E);
11242 case Builtin::BI__builtin_expect:
11243 case Builtin::BI__builtin_expect_with_probability:
11244 return Visit(E->getArg(0));
11246 case Builtin::BI__builtin_ffs:
11247 case Builtin::BI__builtin_ffsl:
11248 case Builtin::BI__builtin_ffsll: {
11250 if (!EvaluateInteger(E->getArg(0), Val, Info))
11253 unsigned N = Val.countTrailingZeros();
11254 return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
11257 case Builtin::BI__builtin_fpclassify: {
11259 if (!EvaluateFloat(E->getArg(5), Val, Info))
11262 switch (Val.getCategory()) {
11263 case APFloat::fcNaN: Arg = 0; break;
11264 case APFloat::fcInfinity: Arg = 1; break;
11265 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
11266 case APFloat::fcZero: Arg = 4; break;
11268 return Visit(E->getArg(Arg));
11271 case Builtin::BI__builtin_isinf_sign: {
11273 return EvaluateFloat(E->getArg(0), Val, Info) &&
11274 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
11277 case Builtin::BI__builtin_isinf: {
11279 return EvaluateFloat(E->getArg(0), Val, Info) &&
11280 Success(Val.isInfinity() ? 1 : 0, E);
11283 case Builtin::BI__builtin_isfinite: {
11285 return EvaluateFloat(E->getArg(0), Val, Info) &&
11286 Success(Val.isFinite() ? 1 : 0, E);
11289 case Builtin::BI__builtin_isnan: {
11291 return EvaluateFloat(E->getArg(0), Val, Info) &&
11292 Success(Val.isNaN() ? 1 : 0, E);
11295 case Builtin::BI__builtin_isnormal: {
11297 return EvaluateFloat(E->getArg(0), Val, Info) &&
11298 Success(Val.isNormal() ? 1 : 0, E);
11301 case Builtin::BI__builtin_parity:
11302 case Builtin::BI__builtin_parityl:
11303 case Builtin::BI__builtin_parityll: {
11305 if (!EvaluateInteger(E->getArg(0), Val, Info))
11308 return Success(Val.countPopulation() % 2, E);
11311 case Builtin::BI__builtin_popcount:
11312 case Builtin::BI__builtin_popcountl:
11313 case Builtin::BI__builtin_popcountll: {
11315 if (!EvaluateInteger(E->getArg(0), Val, Info))
11318 return Success(Val.countPopulation(), E);
11321 case Builtin::BIstrlen:
11322 case Builtin::BIwcslen:
11323 // A call to strlen is not a constant expression.
11324 if (Info.getLangOpts().CPlusPlus11)
11325 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
11326 << /*isConstexpr*/0 << /*isConstructor*/0
11327 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
11329 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
11331 case Builtin::BI__builtin_strlen:
11332 case Builtin::BI__builtin_wcslen: {
11333 // As an extension, we support __builtin_strlen() as a constant expression,
11334 // and support folding strlen() to a constant.
11336 if (!EvaluatePointer(E->getArg(0), String, Info))
11339 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
11341 // Fast path: if it's a string literal, search the string value.
11342 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
11343 String.getLValueBase().dyn_cast<const Expr *>())) {
11344 // The string literal may have embedded null characters. Find the first
11345 // one and truncate there.
11346 StringRef Str = S->getBytes();
11347 int64_t Off = String.Offset.getQuantity();
11348 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
11349 S->getCharByteWidth() == 1 &&
11350 // FIXME: Add fast-path for wchar_t too.
11351 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) {
11352 Str = Str.substr(Off);
11354 StringRef::size_type Pos = Str.find(0);
11355 if (Pos != StringRef::npos)
11356 Str = Str.substr(0, Pos);
11358 return Success(Str.size(), E);
11361 // Fall through to slow path to issue appropriate diagnostic.
11364 // Slow path: scan the bytes of the string looking for the terminating 0.
11365 for (uint64_t Strlen = 0; /**/; ++Strlen) {
11367 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) ||
11370 if (!Char.getInt())
11371 return Success(Strlen, E);
11372 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1))
11377 case Builtin::BIstrcmp:
11378 case Builtin::BIwcscmp:
11379 case Builtin::BIstrncmp:
11380 case Builtin::BIwcsncmp:
11381 case Builtin::BImemcmp:
11382 case Builtin::BIbcmp:
11383 case Builtin::BIwmemcmp:
11384 // A call to strlen is not a constant expression.
11385 if (Info.getLangOpts().CPlusPlus11)
11386 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
11387 << /*isConstexpr*/0 << /*isConstructor*/0
11388 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
11390 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
11392 case Builtin::BI__builtin_strcmp:
11393 case Builtin::BI__builtin_wcscmp:
11394 case Builtin::BI__builtin_strncmp:
11395 case Builtin::BI__builtin_wcsncmp:
11396 case Builtin::BI__builtin_memcmp:
11397 case Builtin::BI__builtin_bcmp:
11398 case Builtin::BI__builtin_wmemcmp: {
11399 LValue String1, String2;
11400 if (!EvaluatePointer(E->getArg(0), String1, Info) ||
11401 !EvaluatePointer(E->getArg(1), String2, Info))
11404 uint64_t MaxLength = uint64_t(-1);
11405 if (BuiltinOp != Builtin::BIstrcmp &&
11406 BuiltinOp != Builtin::BIwcscmp &&
11407 BuiltinOp != Builtin::BI__builtin_strcmp &&
11408 BuiltinOp != Builtin::BI__builtin_wcscmp) {
11410 if (!EvaluateInteger(E->getArg(2), N, Info))
11412 MaxLength = N.getExtValue();
11415 // Empty substrings compare equal by definition.
11416 if (MaxLength == 0u)
11417 return Success(0, E);
11419 if (!String1.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
11420 !String2.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
11421 String1.Designator.Invalid || String2.Designator.Invalid)
11424 QualType CharTy1 = String1.Designator.getType(Info.Ctx);
11425 QualType CharTy2 = String2.Designator.getType(Info.Ctx);
11427 bool IsRawByte = BuiltinOp == Builtin::BImemcmp ||
11428 BuiltinOp == Builtin::BIbcmp ||
11429 BuiltinOp == Builtin::BI__builtin_memcmp ||
11430 BuiltinOp == Builtin::BI__builtin_bcmp;
11432 assert(IsRawByte ||
11433 (Info.Ctx.hasSameUnqualifiedType(
11434 CharTy1, E->getArg(0)->getType()->getPointeeType()) &&
11435 Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2)));
11437 // For memcmp, allow comparing any arrays of '[[un]signed] char' or
11438 // 'char8_t', but no other types.
11440 !(isOneByteCharacterType(CharTy1) && isOneByteCharacterType(CharTy2))) {
11441 // FIXME: Consider using our bit_cast implementation to support this.
11442 Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported)
11443 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
11444 << CharTy1 << CharTy2;
11448 const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) {
11449 return handleLValueToRValueConversion(Info, E, CharTy1, String1, Char1) &&
11450 handleLValueToRValueConversion(Info, E, CharTy2, String2, Char2) &&
11451 Char1.isInt() && Char2.isInt();
11453 const auto &AdvanceElems = [&] {
11454 return HandleLValueArrayAdjustment(Info, E, String1, CharTy1, 1) &&
11455 HandleLValueArrayAdjustment(Info, E, String2, CharTy2, 1);
11459 (BuiltinOp != Builtin::BImemcmp && BuiltinOp != Builtin::BIbcmp &&
11460 BuiltinOp != Builtin::BIwmemcmp &&
11461 BuiltinOp != Builtin::BI__builtin_memcmp &&
11462 BuiltinOp != Builtin::BI__builtin_bcmp &&
11463 BuiltinOp != Builtin::BI__builtin_wmemcmp);
11464 bool IsWide = BuiltinOp == Builtin::BIwcscmp ||
11465 BuiltinOp == Builtin::BIwcsncmp ||
11466 BuiltinOp == Builtin::BIwmemcmp ||
11467 BuiltinOp == Builtin::BI__builtin_wcscmp ||
11468 BuiltinOp == Builtin::BI__builtin_wcsncmp ||
11469 BuiltinOp == Builtin::BI__builtin_wmemcmp;
11471 for (; MaxLength; --MaxLength) {
11472 APValue Char1, Char2;
11473 if (!ReadCurElems(Char1, Char2))
11475 if (Char1.getInt().ne(Char2.getInt())) {
11476 if (IsWide) // wmemcmp compares with wchar_t signedness.
11477 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
11478 // memcmp always compares unsigned chars.
11479 return Success(Char1.getInt().ult(Char2.getInt()) ? -1 : 1, E);
11481 if (StopAtNull && !Char1.getInt())
11482 return Success(0, E);
11483 assert(!(StopAtNull && !Char2.getInt()));
11484 if (!AdvanceElems())
11487 // We hit the strncmp / memcmp limit.
11488 return Success(0, E);
11491 case Builtin::BI__atomic_always_lock_free:
11492 case Builtin::BI__atomic_is_lock_free:
11493 case Builtin::BI__c11_atomic_is_lock_free: {
11495 if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
11498 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
11499 // of two less than the maximum inline atomic width, we know it is
11500 // lock-free. If the size isn't a power of two, or greater than the
11501 // maximum alignment where we promote atomics, we know it is not lock-free
11502 // (at least not in the sense of atomic_is_lock_free). Otherwise,
11503 // the answer can only be determined at runtime; for example, 16-byte
11504 // atomics have lock-free implementations on some, but not all,
11505 // x86-64 processors.
11507 // Check power-of-two.
11508 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
11509 if (Size.isPowerOfTwo()) {
11510 // Check against inlining width.
11511 unsigned InlineWidthBits =
11512 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
11513 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
11514 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
11515 Size == CharUnits::One() ||
11516 E->getArg(1)->isNullPointerConstant(Info.Ctx,
11517 Expr::NPC_NeverValueDependent))
11518 // OK, we will inline appropriately-aligned operations of this size,
11519 // and _Atomic(T) is appropriately-aligned.
11520 return Success(1, E);
11522 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
11523 castAs<PointerType>()->getPointeeType();
11524 if (!PointeeType->isIncompleteType() &&
11525 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
11526 // OK, we will inline operations on this object.
11527 return Success(1, E);
11532 return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
11533 Success(0, E) : Error(E);
11535 case Builtin::BIomp_is_initial_device:
11536 // We can decide statically which value the runtime would return if called.
11537 return Success(Info.getLangOpts().OpenMPIsDevice ? 0 : 1, E);
11538 case Builtin::BI__builtin_add_overflow:
11539 case Builtin::BI__builtin_sub_overflow:
11540 case Builtin::BI__builtin_mul_overflow:
11541 case Builtin::BI__builtin_sadd_overflow:
11542 case Builtin::BI__builtin_uadd_overflow:
11543 case Builtin::BI__builtin_uaddl_overflow:
11544 case Builtin::BI__builtin_uaddll_overflow:
11545 case Builtin::BI__builtin_usub_overflow:
11546 case Builtin::BI__builtin_usubl_overflow:
11547 case Builtin::BI__builtin_usubll_overflow:
11548 case Builtin::BI__builtin_umul_overflow:
11549 case Builtin::BI__builtin_umull_overflow:
11550 case Builtin::BI__builtin_umulll_overflow:
11551 case Builtin::BI__builtin_saddl_overflow:
11552 case Builtin::BI__builtin_saddll_overflow:
11553 case Builtin::BI__builtin_ssub_overflow:
11554 case Builtin::BI__builtin_ssubl_overflow:
11555 case Builtin::BI__builtin_ssubll_overflow:
11556 case Builtin::BI__builtin_smul_overflow:
11557 case Builtin::BI__builtin_smull_overflow:
11558 case Builtin::BI__builtin_smulll_overflow: {
11559 LValue ResultLValue;
11562 QualType ResultType = E->getArg(2)->getType()->getPointeeType();
11563 if (!EvaluateInteger(E->getArg(0), LHS, Info) ||
11564 !EvaluateInteger(E->getArg(1), RHS, Info) ||
11565 !EvaluatePointer(E->getArg(2), ResultLValue, Info))
11569 bool DidOverflow = false;
11571 // If the types don't have to match, enlarge all 3 to the largest of them.
11572 if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
11573 BuiltinOp == Builtin::BI__builtin_sub_overflow ||
11574 BuiltinOp == Builtin::BI__builtin_mul_overflow) {
11575 bool IsSigned = LHS.isSigned() || RHS.isSigned() ||
11576 ResultType->isSignedIntegerOrEnumerationType();
11577 bool AllSigned = LHS.isSigned() && RHS.isSigned() &&
11578 ResultType->isSignedIntegerOrEnumerationType();
11579 uint64_t LHSSize = LHS.getBitWidth();
11580 uint64_t RHSSize = RHS.getBitWidth();
11581 uint64_t ResultSize = Info.Ctx.getTypeSize(ResultType);
11582 uint64_t MaxBits = std::max(std::max(LHSSize, RHSSize), ResultSize);
11584 // Add an additional bit if the signedness isn't uniformly agreed to. We
11585 // could do this ONLY if there is a signed and an unsigned that both have
11586 // MaxBits, but the code to check that is pretty nasty. The issue will be
11587 // caught in the shrink-to-result later anyway.
11588 if (IsSigned && !AllSigned)
11591 LHS = APSInt(LHS.extOrTrunc(MaxBits), !IsSigned);
11592 RHS = APSInt(RHS.extOrTrunc(MaxBits), !IsSigned);
11593 Result = APSInt(MaxBits, !IsSigned);
11596 // Find largest int.
11597 switch (BuiltinOp) {
11599 llvm_unreachable("Invalid value for BuiltinOp");
11600 case Builtin::BI__builtin_add_overflow:
11601 case Builtin::BI__builtin_sadd_overflow:
11602 case Builtin::BI__builtin_saddl_overflow:
11603 case Builtin::BI__builtin_saddll_overflow:
11604 case Builtin::BI__builtin_uadd_overflow:
11605 case Builtin::BI__builtin_uaddl_overflow:
11606 case Builtin::BI__builtin_uaddll_overflow:
11607 Result = LHS.isSigned() ? LHS.sadd_ov(RHS, DidOverflow)
11608 : LHS.uadd_ov(RHS, DidOverflow);
11610 case Builtin::BI__builtin_sub_overflow:
11611 case Builtin::BI__builtin_ssub_overflow:
11612 case Builtin::BI__builtin_ssubl_overflow:
11613 case Builtin::BI__builtin_ssubll_overflow:
11614 case Builtin::BI__builtin_usub_overflow:
11615 case Builtin::BI__builtin_usubl_overflow:
11616 case Builtin::BI__builtin_usubll_overflow:
11617 Result = LHS.isSigned() ? LHS.ssub_ov(RHS, DidOverflow)
11618 : LHS.usub_ov(RHS, DidOverflow);
11620 case Builtin::BI__builtin_mul_overflow:
11621 case Builtin::BI__builtin_smul_overflow:
11622 case Builtin::BI__builtin_smull_overflow:
11623 case Builtin::BI__builtin_smulll_overflow:
11624 case Builtin::BI__builtin_umul_overflow:
11625 case Builtin::BI__builtin_umull_overflow:
11626 case Builtin::BI__builtin_umulll_overflow:
11627 Result = LHS.isSigned() ? LHS.smul_ov(RHS, DidOverflow)
11628 : LHS.umul_ov(RHS, DidOverflow);
11632 // In the case where multiple sizes are allowed, truncate and see if
11633 // the values are the same.
11634 if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
11635 BuiltinOp == Builtin::BI__builtin_sub_overflow ||
11636 BuiltinOp == Builtin::BI__builtin_mul_overflow) {
11637 // APSInt doesn't have a TruncOrSelf, so we use extOrTrunc instead,
11638 // since it will give us the behavior of a TruncOrSelf in the case where
11639 // its parameter <= its size. We previously set Result to be at least the
11640 // type-size of the result, so getTypeSize(ResultType) <= Result.BitWidth
11641 // will work exactly like TruncOrSelf.
11642 APSInt Temp = Result.extOrTrunc(Info.Ctx.getTypeSize(ResultType));
11643 Temp.setIsSigned(ResultType->isSignedIntegerOrEnumerationType());
11645 if (!APSInt::isSameValue(Temp, Result))
11646 DidOverflow = true;
11650 APValue APV{Result};
11651 if (!handleAssignment(Info, E, ResultLValue, ResultType, APV))
11653 return Success(DidOverflow, E);
11658 /// Determine whether this is a pointer past the end of the complete
11659 /// object referred to by the lvalue.
11660 static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
11661 const LValue &LV) {
11662 // A null pointer can be viewed as being "past the end" but we don't
11663 // choose to look at it that way here.
11664 if (!LV.getLValueBase())
11667 // If the designator is valid and refers to a subobject, we're not pointing
11669 if (!LV.getLValueDesignator().Invalid &&
11670 !LV.getLValueDesignator().isOnePastTheEnd())
11673 // A pointer to an incomplete type might be past-the-end if the type's size is
11674 // zero. We cannot tell because the type is incomplete.
11675 QualType Ty = getType(LV.getLValueBase());
11676 if (Ty->isIncompleteType())
11679 // We're a past-the-end pointer if we point to the byte after the object,
11680 // no matter what our type or path is.
11681 auto Size = Ctx.getTypeSizeInChars(Ty);
11682 return LV.getLValueOffset() == Size;
11687 /// Data recursive integer evaluator of certain binary operators.
11689 /// We use a data recursive algorithm for binary operators so that we are able
11690 /// to handle extreme cases of chained binary operators without causing stack
11692 class DataRecursiveIntBinOpEvaluator {
11693 struct EvalResult {
11697 EvalResult() : Failed(false) { }
11699 void swap(EvalResult &RHS) {
11701 Failed = RHS.Failed;
11702 RHS.Failed = false;
11708 EvalResult LHSResult; // meaningful only for binary operator expression.
11709 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
11712 Job(Job &&) = default;
11714 void startSpeculativeEval(EvalInfo &Info) {
11715 SpecEvalRAII = SpeculativeEvaluationRAII(Info);
11719 SpeculativeEvaluationRAII SpecEvalRAII;
11722 SmallVector<Job, 16> Queue;
11724 IntExprEvaluator &IntEval;
11726 APValue &FinalResult;
11729 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
11730 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
11732 /// True if \param E is a binary operator that we are going to handle
11733 /// data recursively.
11734 /// We handle binary operators that are comma, logical, or that have operands
11735 /// with integral or enumeration type.
11736 static bool shouldEnqueue(const BinaryOperator *E) {
11737 return E->getOpcode() == BO_Comma || E->isLogicalOp() ||
11738 (E->isRValue() && E->getType()->isIntegralOrEnumerationType() &&
11739 E->getLHS()->getType()->isIntegralOrEnumerationType() &&
11740 E->getRHS()->getType()->isIntegralOrEnumerationType());
11743 bool Traverse(const BinaryOperator *E) {
11745 EvalResult PrevResult;
11746 while (!Queue.empty())
11747 process(PrevResult);
11749 if (PrevResult.Failed) return false;
11751 FinalResult.swap(PrevResult.Val);
11756 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
11757 return IntEval.Success(Value, E, Result);
11759 bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
11760 return IntEval.Success(Value, E, Result);
11762 bool Error(const Expr *E) {
11763 return IntEval.Error(E);
11765 bool Error(const Expr *E, diag::kind D) {
11766 return IntEval.Error(E, D);
11769 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
11770 return Info.CCEDiag(E, D);
11773 // Returns true if visiting the RHS is necessary, false otherwise.
11774 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
11775 bool &SuppressRHSDiags);
11777 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
11778 const BinaryOperator *E, APValue &Result);
11780 void EvaluateExpr(const Expr *E, EvalResult &Result) {
11781 Result.Failed = !Evaluate(Result.Val, Info, E);
11783 Result.Val = APValue();
11786 void process(EvalResult &Result);
11788 void enqueue(const Expr *E) {
11789 E = E->IgnoreParens();
11790 Queue.resize(Queue.size()+1);
11791 Queue.back().E = E;
11792 Queue.back().Kind = Job::AnyExprKind;
11798 bool DataRecursiveIntBinOpEvaluator::
11799 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
11800 bool &SuppressRHSDiags) {
11801 if (E->getOpcode() == BO_Comma) {
11802 // Ignore LHS but note if we could not evaluate it.
11803 if (LHSResult.Failed)
11804 return Info.noteSideEffect();
11808 if (E->isLogicalOp()) {
11810 if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) {
11811 // We were able to evaluate the LHS, see if we can get away with not
11812 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
11813 if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
11814 Success(LHSAsBool, E, LHSResult.Val);
11815 return false; // Ignore RHS
11818 LHSResult.Failed = true;
11820 // Since we weren't able to evaluate the left hand side, it
11821 // might have had side effects.
11822 if (!Info.noteSideEffect())
11825 // We can't evaluate the LHS; however, sometimes the result
11826 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
11827 // Don't ignore RHS and suppress diagnostics from this arm.
11828 SuppressRHSDiags = true;
11834 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
11835 E->getRHS()->getType()->isIntegralOrEnumerationType());
11837 if (LHSResult.Failed && !Info.noteFailure())
11838 return false; // Ignore RHS;
11843 static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index,
11845 // Compute the new offset in the appropriate width, wrapping at 64 bits.
11846 // FIXME: When compiling for a 32-bit target, we should use 32-bit
11848 assert(!LVal.hasLValuePath() && "have designator for integer lvalue");
11849 CharUnits &Offset = LVal.getLValueOffset();
11850 uint64_t Offset64 = Offset.getQuantity();
11851 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
11852 Offset = CharUnits::fromQuantity(IsSub ? Offset64 - Index64
11853 : Offset64 + Index64);
11856 bool DataRecursiveIntBinOpEvaluator::
11857 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
11858 const BinaryOperator *E, APValue &Result) {
11859 if (E->getOpcode() == BO_Comma) {
11860 if (RHSResult.Failed)
11862 Result = RHSResult.Val;
11866 if (E->isLogicalOp()) {
11867 bool lhsResult, rhsResult;
11868 bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
11869 bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);
11873 if (E->getOpcode() == BO_LOr)
11874 return Success(lhsResult || rhsResult, E, Result);
11876 return Success(lhsResult && rhsResult, E, Result);
11880 // We can't evaluate the LHS; however, sometimes the result
11881 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
11882 if (rhsResult == (E->getOpcode() == BO_LOr))
11883 return Success(rhsResult, E, Result);
11890 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
11891 E->getRHS()->getType()->isIntegralOrEnumerationType());
11893 if (LHSResult.Failed || RHSResult.Failed)
11896 const APValue &LHSVal = LHSResult.Val;
11897 const APValue &RHSVal = RHSResult.Val;
11899 // Handle cases like (unsigned long)&a + 4.
11900 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
11902 addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub);
11906 // Handle cases like 4 + (unsigned long)&a
11907 if (E->getOpcode() == BO_Add &&
11908 RHSVal.isLValue() && LHSVal.isInt()) {
11910 addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false);
11914 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
11915 // Handle (intptr_t)&&A - (intptr_t)&&B.
11916 if (!LHSVal.getLValueOffset().isZero() ||
11917 !RHSVal.getLValueOffset().isZero())
11919 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
11920 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
11921 if (!LHSExpr || !RHSExpr)
11923 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
11924 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
11925 if (!LHSAddrExpr || !RHSAddrExpr)
11927 // Make sure both labels come from the same function.
11928 if (LHSAddrExpr->getLabel()->getDeclContext() !=
11929 RHSAddrExpr->getLabel()->getDeclContext())
11931 Result = APValue(LHSAddrExpr, RHSAddrExpr);
11935 // All the remaining cases expect both operands to be an integer
11936 if (!LHSVal.isInt() || !RHSVal.isInt())
11939 // Set up the width and signedness manually, in case it can't be deduced
11940 // from the operation we're performing.
11941 // FIXME: Don't do this in the cases where we can deduce it.
11942 APSInt Value(Info.Ctx.getIntWidth(E->getType()),
11943 E->getType()->isUnsignedIntegerOrEnumerationType());
11944 if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(),
11945 RHSVal.getInt(), Value))
11947 return Success(Value, E, Result);
11950 void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
11951 Job &job = Queue.back();
11953 switch (job.Kind) {
11954 case Job::AnyExprKind: {
11955 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
11956 if (shouldEnqueue(Bop)) {
11957 job.Kind = Job::BinOpKind;
11958 enqueue(Bop->getLHS());
11963 EvaluateExpr(job.E, Result);
11968 case Job::BinOpKind: {
11969 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
11970 bool SuppressRHSDiags = false;
11971 if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) {
11975 if (SuppressRHSDiags)
11976 job.startSpeculativeEval(Info);
11977 job.LHSResult.swap(Result);
11978 job.Kind = Job::BinOpVisitedLHSKind;
11979 enqueue(Bop->getRHS());
11983 case Job::BinOpVisitedLHSKind: {
11984 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
11987 Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val);
11993 llvm_unreachable("Invalid Job::Kind!");
11997 /// Used when we determine that we should fail, but can keep evaluating prior to
11998 /// noting that we had a failure.
11999 class DelayedNoteFailureRAII {
12004 DelayedNoteFailureRAII(EvalInfo &Info, bool NoteFailure = true)
12005 : Info(Info), NoteFailure(NoteFailure) {}
12006 ~DelayedNoteFailureRAII() {
12008 bool ContinueAfterFailure = Info.noteFailure();
12009 (void)ContinueAfterFailure;
12010 assert(ContinueAfterFailure &&
12011 "Shouldn't have kept evaluating on failure.");
12016 enum class CmpResult {
12025 template <class SuccessCB, class AfterCB>
12027 EvaluateComparisonBinaryOperator(EvalInfo &Info, const BinaryOperator *E,
12028 SuccessCB &&Success, AfterCB &&DoAfter) {
12029 assert(E->isComparisonOp() && "expected comparison operator");
12030 assert((E->getOpcode() == BO_Cmp ||
12031 E->getType()->isIntegralOrEnumerationType()) &&
12032 "unsupported binary expression evaluation");
12033 auto Error = [&](const Expr *E) {
12034 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
12038 bool IsRelational = E->isRelationalOp() || E->getOpcode() == BO_Cmp;
12039 bool IsEquality = E->isEqualityOp();
12041 QualType LHSTy = E->getLHS()->getType();
12042 QualType RHSTy = E->getRHS()->getType();
12044 if (LHSTy->isIntegralOrEnumerationType() &&
12045 RHSTy->isIntegralOrEnumerationType()) {
12047 bool LHSOK = EvaluateInteger(E->getLHS(), LHS, Info);
12048 if (!LHSOK && !Info.noteFailure())
12050 if (!EvaluateInteger(E->getRHS(), RHS, Info) || !LHSOK)
12053 return Success(CmpResult::Less, E);
12055 return Success(CmpResult::Greater, E);
12056 return Success(CmpResult::Equal, E);
12059 if (LHSTy->isFixedPointType() || RHSTy->isFixedPointType()) {
12060 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHSTy));
12061 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHSTy));
12063 bool LHSOK = EvaluateFixedPointOrInteger(E->getLHS(), LHSFX, Info);
12064 if (!LHSOK && !Info.noteFailure())
12066 if (!EvaluateFixedPointOrInteger(E->getRHS(), RHSFX, Info) || !LHSOK)
12069 return Success(CmpResult::Less, E);
12071 return Success(CmpResult::Greater, E);
12072 return Success(CmpResult::Equal, E);
12075 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
12076 ComplexValue LHS, RHS;
12078 if (E->isAssignmentOp()) {
12080 EvaluateLValue(E->getLHS(), LV, Info);
12082 } else if (LHSTy->isRealFloatingType()) {
12083 LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info);
12085 LHS.makeComplexFloat();
12086 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
12089 LHSOK = EvaluateComplex(E->getLHS(), LHS, Info);
12091 if (!LHSOK && !Info.noteFailure())
12094 if (E->getRHS()->getType()->isRealFloatingType()) {
12095 if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK)
12097 RHS.makeComplexFloat();
12098 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
12099 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
12102 if (LHS.isComplexFloat()) {
12103 APFloat::cmpResult CR_r =
12104 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
12105 APFloat::cmpResult CR_i =
12106 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
12107 bool IsEqual = CR_r == APFloat::cmpEqual && CR_i == APFloat::cmpEqual;
12108 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
12110 assert(IsEquality && "invalid complex comparison");
12111 bool IsEqual = LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
12112 LHS.getComplexIntImag() == RHS.getComplexIntImag();
12113 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
12117 if (LHSTy->isRealFloatingType() &&
12118 RHSTy->isRealFloatingType()) {
12119 APFloat RHS(0.0), LHS(0.0);
12121 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info);
12122 if (!LHSOK && !Info.noteFailure())
12125 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK)
12128 assert(E->isComparisonOp() && "Invalid binary operator!");
12129 auto GetCmpRes = [&]() {
12130 switch (LHS.compare(RHS)) {
12131 case APFloat::cmpEqual:
12132 return CmpResult::Equal;
12133 case APFloat::cmpLessThan:
12134 return CmpResult::Less;
12135 case APFloat::cmpGreaterThan:
12136 return CmpResult::Greater;
12137 case APFloat::cmpUnordered:
12138 return CmpResult::Unordered;
12140 llvm_unreachable("Unrecognised APFloat::cmpResult enum");
12142 return Success(GetCmpRes(), E);
12145 if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
12146 LValue LHSValue, RHSValue;
12148 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
12149 if (!LHSOK && !Info.noteFailure())
12152 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12155 // Reject differing bases from the normal codepath; we special-case
12156 // comparisons to null.
12157 if (!HasSameBase(LHSValue, RHSValue)) {
12158 // Inequalities and subtractions between unrelated pointers have
12159 // unspecified or undefined behavior.
12161 Info.FFDiag(E, diag::note_constexpr_pointer_comparison_unspecified);
12164 // A constant address may compare equal to the address of a symbol.
12165 // The one exception is that address of an object cannot compare equal
12166 // to a null pointer constant.
12167 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
12168 (!RHSValue.Base && !RHSValue.Offset.isZero()))
12170 // It's implementation-defined whether distinct literals will have
12171 // distinct addresses. In clang, the result of such a comparison is
12172 // unspecified, so it is not a constant expression. However, we do know
12173 // that the address of a literal will be non-null.
12174 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
12175 LHSValue.Base && RHSValue.Base)
12177 // We can't tell whether weak symbols will end up pointing to the same
12179 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
12181 // We can't compare the address of the start of one object with the
12182 // past-the-end address of another object, per C++ DR1652.
12183 if ((LHSValue.Base && LHSValue.Offset.isZero() &&
12184 isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) ||
12185 (RHSValue.Base && RHSValue.Offset.isZero() &&
12186 isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)))
12188 // We can't tell whether an object is at the same address as another
12189 // zero sized object.
12190 if ((RHSValue.Base && isZeroSized(LHSValue)) ||
12191 (LHSValue.Base && isZeroSized(RHSValue)))
12193 return Success(CmpResult::Unequal, E);
12196 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
12197 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
12199 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
12200 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
12202 // C++11 [expr.rel]p3:
12203 // Pointers to void (after pointer conversions) can be compared, with a
12204 // result defined as follows: If both pointers represent the same
12205 // address or are both the null pointer value, the result is true if the
12206 // operator is <= or >= and false otherwise; otherwise the result is
12208 // We interpret this as applying to pointers to *cv* void.
12209 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && IsRelational)
12210 Info.CCEDiag(E, diag::note_constexpr_void_comparison);
12212 // C++11 [expr.rel]p2:
12213 // - If two pointers point to non-static data members of the same object,
12214 // or to subobjects or array elements fo such members, recursively, the
12215 // pointer to the later declared member compares greater provided the
12216 // two members have the same access control and provided their class is
12219 // - Otherwise pointer comparisons are unspecified.
12220 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && IsRelational) {
12221 bool WasArrayIndex;
12222 unsigned Mismatch = FindDesignatorMismatch(
12223 getType(LHSValue.Base), LHSDesignator, RHSDesignator, WasArrayIndex);
12224 // At the point where the designators diverge, the comparison has a
12225 // specified value if:
12226 // - we are comparing array indices
12227 // - we are comparing fields of a union, or fields with the same access
12228 // Otherwise, the result is unspecified and thus the comparison is not a
12229 // constant expression.
12230 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
12231 Mismatch < RHSDesignator.Entries.size()) {
12232 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]);
12233 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]);
12235 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
12237 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
12238 << getAsBaseClass(LHSDesignator.Entries[Mismatch])
12239 << RF->getParent() << RF;
12241 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
12242 << getAsBaseClass(RHSDesignator.Entries[Mismatch])
12243 << LF->getParent() << LF;
12244 else if (!LF->getParent()->isUnion() &&
12245 LF->getAccess() != RF->getAccess())
12247 diag::note_constexpr_pointer_comparison_differing_access)
12248 << LF << LF->getAccess() << RF << RF->getAccess()
12249 << LF->getParent();
12253 // The comparison here must be unsigned, and performed with the same
12254 // width as the pointer.
12255 unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy);
12256 uint64_t CompareLHS = LHSOffset.getQuantity();
12257 uint64_t CompareRHS = RHSOffset.getQuantity();
12258 assert(PtrSize <= 64 && "Unexpected pointer width");
12259 uint64_t Mask = ~0ULL >> (64 - PtrSize);
12260 CompareLHS &= Mask;
12261 CompareRHS &= Mask;
12263 // If there is a base and this is a relational operator, we can only
12264 // compare pointers within the object in question; otherwise, the result
12265 // depends on where the object is located in memory.
12266 if (!LHSValue.Base.isNull() && IsRelational) {
12267 QualType BaseTy = getType(LHSValue.Base);
12268 if (BaseTy->isIncompleteType())
12270 CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy);
12271 uint64_t OffsetLimit = Size.getQuantity();
12272 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
12276 if (CompareLHS < CompareRHS)
12277 return Success(CmpResult::Less, E);
12278 if (CompareLHS > CompareRHS)
12279 return Success(CmpResult::Greater, E);
12280 return Success(CmpResult::Equal, E);
12283 if (LHSTy->isMemberPointerType()) {
12284 assert(IsEquality && "unexpected member pointer operation");
12285 assert(RHSTy->isMemberPointerType() && "invalid comparison");
12287 MemberPtr LHSValue, RHSValue;
12289 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info);
12290 if (!LHSOK && !Info.noteFailure())
12293 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12296 // C++11 [expr.eq]p2:
12297 // If both operands are null, they compare equal. Otherwise if only one is
12298 // null, they compare unequal.
12299 if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
12300 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
12301 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
12304 // Otherwise if either is a pointer to a virtual member function, the
12305 // result is unspecified.
12306 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
12307 if (MD->isVirtual())
12308 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
12309 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
12310 if (MD->isVirtual())
12311 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
12313 // Otherwise they compare equal if and only if they would refer to the
12314 // same member of the same most derived object or the same subobject if
12315 // they were dereferenced with a hypothetical object of the associated
12317 bool Equal = LHSValue == RHSValue;
12318 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
12321 if (LHSTy->isNullPtrType()) {
12322 assert(E->isComparisonOp() && "unexpected nullptr operation");
12323 assert(RHSTy->isNullPtrType() && "missing pointer conversion");
12324 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
12325 // are compared, the result is true of the operator is <=, >= or ==, and
12326 // false otherwise.
12327 return Success(CmpResult::Equal, E);
12333 bool RecordExprEvaluator::VisitBinCmp(const BinaryOperator *E) {
12334 if (!CheckLiteralType(Info, E))
12337 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
12338 ComparisonCategoryResult CCR;
12340 case CmpResult::Unequal:
12341 llvm_unreachable("should never produce Unequal for three-way comparison");
12342 case CmpResult::Less:
12343 CCR = ComparisonCategoryResult::Less;
12345 case CmpResult::Equal:
12346 CCR = ComparisonCategoryResult::Equal;
12348 case CmpResult::Greater:
12349 CCR = ComparisonCategoryResult::Greater;
12351 case CmpResult::Unordered:
12352 CCR = ComparisonCategoryResult::Unordered;
12355 // Evaluation succeeded. Lookup the information for the comparison category
12356 // type and fetch the VarDecl for the result.
12357 const ComparisonCategoryInfo &CmpInfo =
12358 Info.Ctx.CompCategories.getInfoForType(E->getType());
12359 const VarDecl *VD = CmpInfo.getValueInfo(CmpInfo.makeWeakResult(CCR))->VD;
12360 // Check and evaluate the result as a constant expression.
12363 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
12365 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result);
12367 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() {
12368 return ExprEvaluatorBaseTy::VisitBinCmp(E);
12372 bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
12373 // We don't call noteFailure immediately because the assignment happens after
12374 // we evaluate LHS and RHS.
12375 if (!Info.keepEvaluatingAfterFailure() && E->isAssignmentOp())
12378 DelayedNoteFailureRAII MaybeNoteFailureLater(Info, E->isAssignmentOp());
12379 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
12380 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
12382 assert((!E->getLHS()->getType()->isIntegralOrEnumerationType() ||
12383 !E->getRHS()->getType()->isIntegralOrEnumerationType()) &&
12384 "DataRecursiveIntBinOpEvaluator should have handled integral types");
12386 if (E->isComparisonOp()) {
12387 // Evaluate builtin binary comparisons by evaluating them as three-way
12388 // comparisons and then translating the result.
12389 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
12390 assert((CR != CmpResult::Unequal || E->isEqualityOp()) &&
12391 "should only produce Unequal for equality comparisons");
12392 bool IsEqual = CR == CmpResult::Equal,
12393 IsLess = CR == CmpResult::Less,
12394 IsGreater = CR == CmpResult::Greater;
12395 auto Op = E->getOpcode();
12398 llvm_unreachable("unsupported binary operator");
12401 return Success(IsEqual == (Op == BO_EQ), E);
12403 return Success(IsLess, E);
12405 return Success(IsGreater, E);
12407 return Success(IsEqual || IsLess, E);
12409 return Success(IsEqual || IsGreater, E);
12412 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() {
12413 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
12417 QualType LHSTy = E->getLHS()->getType();
12418 QualType RHSTy = E->getRHS()->getType();
12420 if (LHSTy->isPointerType() && RHSTy->isPointerType() &&
12421 E->getOpcode() == BO_Sub) {
12422 LValue LHSValue, RHSValue;
12424 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
12425 if (!LHSOK && !Info.noteFailure())
12428 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12431 // Reject differing bases from the normal codepath; we special-case
12432 // comparisons to null.
12433 if (!HasSameBase(LHSValue, RHSValue)) {
12434 // Handle &&A - &&B.
12435 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
12437 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr *>();
12438 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr *>();
12439 if (!LHSExpr || !RHSExpr)
12441 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
12442 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
12443 if (!LHSAddrExpr || !RHSAddrExpr)
12445 // Make sure both labels come from the same function.
12446 if (LHSAddrExpr->getLabel()->getDeclContext() !=
12447 RHSAddrExpr->getLabel()->getDeclContext())
12449 return Success(APValue(LHSAddrExpr, RHSAddrExpr), E);
12451 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
12452 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
12454 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
12455 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
12457 // C++11 [expr.add]p6:
12458 // Unless both pointers point to elements of the same array object, or
12459 // one past the last element of the array object, the behavior is
12461 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
12462 !AreElementsOfSameArray(getType(LHSValue.Base), LHSDesignator,
12464 Info.CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);
12466 QualType Type = E->getLHS()->getType();
12467 QualType ElementType = Type->castAs<PointerType>()->getPointeeType();
12469 CharUnits ElementSize;
12470 if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize))
12473 // As an extension, a type may have zero size (empty struct or union in
12474 // C, array of zero length). Pointer subtraction in such cases has
12475 // undefined behavior, so is not constant.
12476 if (ElementSize.isZero()) {
12477 Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size)
12482 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
12483 // and produce incorrect results when it overflows. Such behavior
12484 // appears to be non-conforming, but is common, so perhaps we should
12485 // assume the standard intended for such cases to be undefined behavior
12486 // and check for them.
12488 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
12489 // overflow in the final conversion to ptrdiff_t.
12490 APSInt LHS(llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
12491 APSInt RHS(llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
12492 APSInt ElemSize(llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true),
12494 APSInt TrueResult = (LHS - RHS) / ElemSize;
12495 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType()));
12497 if (Result.extend(65) != TrueResult &&
12498 !HandleOverflow(Info, E, TrueResult, E->getType()))
12500 return Success(Result, E);
12503 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
12506 /// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
12507 /// a result as the expression's type.
12508 bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
12509 const UnaryExprOrTypeTraitExpr *E) {
12510 switch(E->getKind()) {
12511 case UETT_PreferredAlignOf:
12512 case UETT_AlignOf: {
12513 if (E->isArgumentType())
12514 return Success(GetAlignOfType(Info, E->getArgumentType(), E->getKind()),
12517 return Success(GetAlignOfExpr(Info, E->getArgumentExpr(), E->getKind()),
12521 case UETT_VecStep: {
12522 QualType Ty = E->getTypeOfArgument();
12524 if (Ty->isVectorType()) {
12525 unsigned n = Ty->castAs<VectorType>()->getNumElements();
12527 // The vec_step built-in functions that take a 3-component
12528 // vector return 4. (OpenCL 1.1 spec 6.11.12)
12532 return Success(n, E);
12534 return Success(1, E);
12537 case UETT_SizeOf: {
12538 QualType SrcTy = E->getTypeOfArgument();
12539 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
12540 // the result is the size of the referenced type."
12541 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
12542 SrcTy = Ref->getPointeeType();
12545 if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof))
12547 return Success(Sizeof, E);
12549 case UETT_OpenMPRequiredSimdAlign:
12550 assert(E->isArgumentType());
12552 Info.Ctx.toCharUnitsFromBits(
12553 Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType()))
12558 llvm_unreachable("unknown expr/type trait");
12561 bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
12563 unsigned n = OOE->getNumComponents();
12566 QualType CurrentType = OOE->getTypeSourceInfo()->getType();
12567 for (unsigned i = 0; i != n; ++i) {
12568 OffsetOfNode ON = OOE->getComponent(i);
12569 switch (ON.getKind()) {
12570 case OffsetOfNode::Array: {
12571 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
12573 if (!EvaluateInteger(Idx, IdxResult, Info))
12575 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
12578 CurrentType = AT->getElementType();
12579 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
12580 Result += IdxResult.getSExtValue() * ElementSize;
12584 case OffsetOfNode::Field: {
12585 FieldDecl *MemberDecl = ON.getField();
12586 const RecordType *RT = CurrentType->getAs<RecordType>();
12589 RecordDecl *RD = RT->getDecl();
12590 if (RD->isInvalidDecl()) return false;
12591 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
12592 unsigned i = MemberDecl->getFieldIndex();
12593 assert(i < RL.getFieldCount() && "offsetof field in wrong type");
12594 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
12595 CurrentType = MemberDecl->getType().getNonReferenceType();
12599 case OffsetOfNode::Identifier:
12600 llvm_unreachable("dependent __builtin_offsetof");
12602 case OffsetOfNode::Base: {
12603 CXXBaseSpecifier *BaseSpec = ON.getBase();
12604 if (BaseSpec->isVirtual())
12607 // Find the layout of the class whose base we are looking into.
12608 const RecordType *RT = CurrentType->getAs<RecordType>();
12611 RecordDecl *RD = RT->getDecl();
12612 if (RD->isInvalidDecl()) return false;
12613 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
12615 // Find the base class itself.
12616 CurrentType = BaseSpec->getType();
12617 const RecordType *BaseRT = CurrentType->getAs<RecordType>();
12621 // Add the offset to the base.
12622 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
12627 return Success(Result, OOE);
12630 bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
12631 switch (E->getOpcode()) {
12633 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
12637 // FIXME: Should extension allow i-c-e extension expressions in its scope?
12638 // If so, we could clear the diagnostic ID.
12639 return Visit(E->getSubExpr());
12641 // The result is just the value.
12642 return Visit(E->getSubExpr());
12644 if (!Visit(E->getSubExpr()))
12646 if (!Result.isInt()) return Error(E);
12647 const APSInt &Value = Result.getInt();
12648 if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow() &&
12649 !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
12652 return Success(-Value, E);
12655 if (!Visit(E->getSubExpr()))
12657 if (!Result.isInt()) return Error(E);
12658 return Success(~Result.getInt(), E);
12662 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
12664 return Success(!bres, E);
12669 /// HandleCast - This is used to evaluate implicit or explicit casts where the
12670 /// result type is integer.
12671 bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
12672 const Expr *SubExpr = E->getSubExpr();
12673 QualType DestType = E->getType();
12674 QualType SrcType = SubExpr->getType();
12676 switch (E->getCastKind()) {
12677 case CK_BaseToDerived:
12678 case CK_DerivedToBase:
12679 case CK_UncheckedDerivedToBase:
12682 case CK_ArrayToPointerDecay:
12683 case CK_FunctionToPointerDecay:
12684 case CK_NullToPointer:
12685 case CK_NullToMemberPointer:
12686 case CK_BaseToDerivedMemberPointer:
12687 case CK_DerivedToBaseMemberPointer:
12688 case CK_ReinterpretMemberPointer:
12689 case CK_ConstructorConversion:
12690 case CK_IntegralToPointer:
12692 case CK_VectorSplat:
12693 case CK_IntegralToFloating:
12694 case CK_FloatingCast:
12695 case CK_CPointerToObjCPointerCast:
12696 case CK_BlockPointerToObjCPointerCast:
12697 case CK_AnyPointerToBlockPointerCast:
12698 case CK_ObjCObjectLValueCast:
12699 case CK_FloatingRealToComplex:
12700 case CK_FloatingComplexToReal:
12701 case CK_FloatingComplexCast:
12702 case CK_FloatingComplexToIntegralComplex:
12703 case CK_IntegralRealToComplex:
12704 case CK_IntegralComplexCast:
12705 case CK_IntegralComplexToFloatingComplex:
12706 case CK_BuiltinFnToFnPtr:
12707 case CK_ZeroToOCLOpaqueType:
12708 case CK_NonAtomicToAtomic:
12709 case CK_AddressSpaceConversion:
12710 case CK_IntToOCLSampler:
12711 case CK_FixedPointCast:
12712 case CK_IntegralToFixedPoint:
12713 llvm_unreachable("invalid cast kind for integral value");
12717 case CK_LValueBitCast:
12718 case CK_ARCProduceObject:
12719 case CK_ARCConsumeObject:
12720 case CK_ARCReclaimReturnedObject:
12721 case CK_ARCExtendBlockObject:
12722 case CK_CopyAndAutoreleaseBlockObject:
12725 case CK_UserDefinedConversion:
12726 case CK_LValueToRValue:
12727 case CK_AtomicToNonAtomic:
12729 case CK_LValueToRValueBitCast:
12730 return ExprEvaluatorBaseTy::VisitCastExpr(E);
12732 case CK_MemberPointerToBoolean:
12733 case CK_PointerToBoolean:
12734 case CK_IntegralToBoolean:
12735 case CK_FloatingToBoolean:
12736 case CK_BooleanToSignedIntegral:
12737 case CK_FloatingComplexToBoolean:
12738 case CK_IntegralComplexToBoolean: {
12740 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info))
12742 uint64_t IntResult = BoolResult;
12743 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
12744 IntResult = (uint64_t)-1;
12745 return Success(IntResult, E);
12748 case CK_FixedPointToIntegral: {
12749 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SrcType));
12750 if (!EvaluateFixedPoint(SubExpr, Src, Info))
12753 llvm::APSInt Result = Src.convertToInt(
12754 Info.Ctx.getIntWidth(DestType),
12755 DestType->isSignedIntegerOrEnumerationType(), &Overflowed);
12756 if (Overflowed && !HandleOverflow(Info, E, Result, DestType))
12758 return Success(Result, E);
12761 case CK_FixedPointToBoolean: {
12762 // Unsigned padding does not affect this.
12764 if (!Evaluate(Val, Info, SubExpr))
12766 return Success(Val.getFixedPoint().getBoolValue(), E);
12769 case CK_IntegralCast: {
12770 if (!Visit(SubExpr))
12773 if (!Result.isInt()) {
12774 // Allow casts of address-of-label differences if they are no-ops
12775 // or narrowing. (The narrowing case isn't actually guaranteed to
12776 // be constant-evaluatable except in some narrow cases which are hard
12777 // to detect here. We let it through on the assumption the user knows
12778 // what they are doing.)
12779 if (Result.isAddrLabelDiff())
12780 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
12781 // Only allow casts of lvalues if they are lossless.
12782 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
12785 return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
12786 Result.getInt()), E);
12789 case CK_PointerToIntegral: {
12790 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
12793 if (!EvaluatePointer(SubExpr, LV, Info))
12796 if (LV.getLValueBase()) {
12797 // Only allow based lvalue casts if they are lossless.
12798 // FIXME: Allow a larger integer size than the pointer size, and allow
12799 // narrowing back down to pointer width in subsequent integral casts.
12800 // FIXME: Check integer type's active bits, not its type size.
12801 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
12804 LV.Designator.setInvalid();
12805 LV.moveInto(Result);
12812 if (!V.toIntegralConstant(AsInt, SrcType, Info.Ctx))
12813 llvm_unreachable("Can't cast this!");
12815 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
12818 case CK_IntegralComplexToReal: {
12820 if (!EvaluateComplex(SubExpr, C, Info))
12822 return Success(C.getComplexIntReal(), E);
12825 case CK_FloatingToIntegral: {
12827 if (!EvaluateFloat(SubExpr, F, Info))
12831 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
12833 return Success(Value, E);
12837 llvm_unreachable("unknown cast resulting in integral value");
12840 bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
12841 if (E->getSubExpr()->getType()->isAnyComplexType()) {
12843 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
12845 if (!LV.isComplexInt())
12847 return Success(LV.getComplexIntReal(), E);
12850 return Visit(E->getSubExpr());
12853 bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
12854 if (E->getSubExpr()->getType()->isComplexIntegerType()) {
12856 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
12858 if (!LV.isComplexInt())
12860 return Success(LV.getComplexIntImag(), E);
12863 VisitIgnoredValue(E->getSubExpr());
12864 return Success(0, E);
12867 bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
12868 return Success(E->getPackLength(), E);
12871 bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
12872 return Success(E->getValue(), E);
12875 bool IntExprEvaluator::VisitConceptSpecializationExpr(
12876 const ConceptSpecializationExpr *E) {
12877 return Success(E->isSatisfied(), E);
12880 bool IntExprEvaluator::VisitRequiresExpr(const RequiresExpr *E) {
12881 return Success(E->isSatisfied(), E);
12884 bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
12885 switch (E->getOpcode()) {
12887 // Invalid unary operators
12890 // The result is just the value.
12891 return Visit(E->getSubExpr());
12893 if (!Visit(E->getSubExpr())) return false;
12894 if (!Result.isFixedPoint())
12897 APFixedPoint Negated = Result.getFixedPoint().negate(&Overflowed);
12898 if (Overflowed && !HandleOverflow(Info, E, Negated, E->getType()))
12900 return Success(Negated, E);
12904 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
12906 return Success(!bres, E);
12911 bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) {
12912 const Expr *SubExpr = E->getSubExpr();
12913 QualType DestType = E->getType();
12914 assert(DestType->isFixedPointType() &&
12915 "Expected destination type to be a fixed point type");
12916 auto DestFXSema = Info.Ctx.getFixedPointSemantics(DestType);
12918 switch (E->getCastKind()) {
12919 case CK_FixedPointCast: {
12920 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SubExpr->getType()));
12921 if (!EvaluateFixedPoint(SubExpr, Src, Info))
12924 APFixedPoint Result = Src.convert(DestFXSema, &Overflowed);
12926 if (Info.checkingForUndefinedBehavior())
12927 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
12928 diag::warn_fixedpoint_constant_overflow)
12929 << Result.toString() << E->getType();
12930 else if (!HandleOverflow(Info, E, Result, E->getType()))
12933 return Success(Result, E);
12935 case CK_IntegralToFixedPoint: {
12937 if (!EvaluateInteger(SubExpr, Src, Info))
12941 APFixedPoint IntResult = APFixedPoint::getFromIntValue(
12942 Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed);
12945 if (Info.checkingForUndefinedBehavior())
12946 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
12947 diag::warn_fixedpoint_constant_overflow)
12948 << IntResult.toString() << E->getType();
12949 else if (!HandleOverflow(Info, E, IntResult, E->getType()))
12953 return Success(IntResult, E);
12956 case CK_LValueToRValue:
12957 return ExprEvaluatorBaseTy::VisitCastExpr(E);
12963 bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
12964 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
12965 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
12967 const Expr *LHS = E->getLHS();
12968 const Expr *RHS = E->getRHS();
12969 FixedPointSemantics ResultFXSema =
12970 Info.Ctx.getFixedPointSemantics(E->getType());
12972 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHS->getType()));
12973 if (!EvaluateFixedPointOrInteger(LHS, LHSFX, Info))
12975 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHS->getType()));
12976 if (!EvaluateFixedPointOrInteger(RHS, RHSFX, Info))
12979 bool OpOverflow = false, ConversionOverflow = false;
12980 APFixedPoint Result(LHSFX.getSemantics());
12981 switch (E->getOpcode()) {
12983 Result = LHSFX.add(RHSFX, &OpOverflow)
12984 .convert(ResultFXSema, &ConversionOverflow);
12988 Result = LHSFX.sub(RHSFX, &OpOverflow)
12989 .convert(ResultFXSema, &ConversionOverflow);
12993 Result = LHSFX.mul(RHSFX, &OpOverflow)
12994 .convert(ResultFXSema, &ConversionOverflow);
12998 if (RHSFX.getValue() == 0) {
12999 Info.FFDiag(E, diag::note_expr_divide_by_zero);
13002 Result = LHSFX.div(RHSFX, &OpOverflow)
13003 .convert(ResultFXSema, &ConversionOverflow);
13009 if (OpOverflow || ConversionOverflow) {
13010 if (Info.checkingForUndefinedBehavior())
13011 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13012 diag::warn_fixedpoint_constant_overflow)
13013 << Result.toString() << E->getType();
13014 else if (!HandleOverflow(Info, E, Result, E->getType()))
13017 return Success(Result, E);
13020 //===----------------------------------------------------------------------===//
13021 // Float Evaluation
13022 //===----------------------------------------------------------------------===//
13025 class FloatExprEvaluator
13026 : public ExprEvaluatorBase<FloatExprEvaluator> {
13029 FloatExprEvaluator(EvalInfo &info, APFloat &result)
13030 : ExprEvaluatorBaseTy(info), Result(result) {}
13032 bool Success(const APValue &V, const Expr *e) {
13033 Result = V.getFloat();
13037 bool ZeroInitialization(const Expr *E) {
13038 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
13042 bool VisitCallExpr(const CallExpr *E);
13044 bool VisitUnaryOperator(const UnaryOperator *E);
13045 bool VisitBinaryOperator(const BinaryOperator *E);
13046 bool VisitFloatingLiteral(const FloatingLiteral *E);
13047 bool VisitCastExpr(const CastExpr *E);
13049 bool VisitUnaryReal(const UnaryOperator *E);
13050 bool VisitUnaryImag(const UnaryOperator *E);
13052 // FIXME: Missing: array subscript of vector, member of vector
13054 } // end anonymous namespace
13056 static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
13057 assert(E->isRValue() && E->getType()->isRealFloatingType());
13058 return FloatExprEvaluator(Info, Result).Visit(E);
13061 static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
13065 llvm::APFloat &Result) {
13066 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
13067 if (!S) return false;
13069 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);
13073 // Treat empty strings as if they were zero.
13074 if (S->getString().empty())
13075 fill = llvm::APInt(32, 0);
13076 else if (S->getString().getAsInteger(0, fill))
13079 if (Context.getTargetInfo().isNan2008()) {
13081 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
13083 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
13085 // Prior to IEEE 754-2008, architectures were allowed to choose whether
13086 // the first bit of their significand was set for qNaN or sNaN. MIPS chose
13087 // a different encoding to what became a standard in 2008, and for pre-
13088 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
13089 // sNaN. This is now known as "legacy NaN" encoding.
13091 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
13093 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
13099 bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
13100 switch (E->getBuiltinCallee()) {
13102 return ExprEvaluatorBaseTy::VisitCallExpr(E);
13104 case Builtin::BI__builtin_huge_val:
13105 case Builtin::BI__builtin_huge_valf:
13106 case Builtin::BI__builtin_huge_vall:
13107 case Builtin::BI__builtin_huge_valf128:
13108 case Builtin::BI__builtin_inf:
13109 case Builtin::BI__builtin_inff:
13110 case Builtin::BI__builtin_infl:
13111 case Builtin::BI__builtin_inff128: {
13112 const llvm::fltSemantics &Sem =
13113 Info.Ctx.getFloatTypeSemantics(E->getType());
13114 Result = llvm::APFloat::getInf(Sem);
13118 case Builtin::BI__builtin_nans:
13119 case Builtin::BI__builtin_nansf:
13120 case Builtin::BI__builtin_nansl:
13121 case Builtin::BI__builtin_nansf128:
13122 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
13127 case Builtin::BI__builtin_nan:
13128 case Builtin::BI__builtin_nanf:
13129 case Builtin::BI__builtin_nanl:
13130 case Builtin::BI__builtin_nanf128:
13131 // If this is __builtin_nan() turn this into a nan, otherwise we
13132 // can't constant fold it.
13133 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
13138 case Builtin::BI__builtin_fabs:
13139 case Builtin::BI__builtin_fabsf:
13140 case Builtin::BI__builtin_fabsl:
13141 case Builtin::BI__builtin_fabsf128:
13142 if (!EvaluateFloat(E->getArg(0), Result, Info))
13145 if (Result.isNegative())
13146 Result.changeSign();
13149 // FIXME: Builtin::BI__builtin_powi
13150 // FIXME: Builtin::BI__builtin_powif
13151 // FIXME: Builtin::BI__builtin_powil
13153 case Builtin::BI__builtin_copysign:
13154 case Builtin::BI__builtin_copysignf:
13155 case Builtin::BI__builtin_copysignl:
13156 case Builtin::BI__builtin_copysignf128: {
13158 if (!EvaluateFloat(E->getArg(0), Result, Info) ||
13159 !EvaluateFloat(E->getArg(1), RHS, Info))
13161 Result.copySign(RHS);
13167 bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
13168 if (E->getSubExpr()->getType()->isAnyComplexType()) {
13170 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
13172 Result = CV.FloatReal;
13176 return Visit(E->getSubExpr());
13179 bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
13180 if (E->getSubExpr()->getType()->isAnyComplexType()) {
13182 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
13184 Result = CV.FloatImag;
13188 VisitIgnoredValue(E->getSubExpr());
13189 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
13190 Result = llvm::APFloat::getZero(Sem);
13194 bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13195 switch (E->getOpcode()) {
13196 default: return Error(E);
13198 return EvaluateFloat(E->getSubExpr(), Result, Info);
13200 if (!EvaluateFloat(E->getSubExpr(), Result, Info))
13202 Result.changeSign();
13207 bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
13208 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
13209 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13212 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info);
13213 if (!LHSOK && !Info.noteFailure())
13215 return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK &&
13216 handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS);
13219 bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
13220 Result = E->getValue();
13224 bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
13225 const Expr* SubExpr = E->getSubExpr();
13227 switch (E->getCastKind()) {
13229 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13231 case CK_IntegralToFloating: {
13233 return EvaluateInteger(SubExpr, IntResult, Info) &&
13234 HandleIntToFloatCast(Info, E, SubExpr->getType(), IntResult,
13235 E->getType(), Result);
13238 case CK_FloatingCast: {
13239 if (!Visit(SubExpr))
13241 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
13245 case CK_FloatingComplexToReal: {
13247 if (!EvaluateComplex(SubExpr, V, Info))
13249 Result = V.getComplexFloatReal();
13255 //===----------------------------------------------------------------------===//
13256 // Complex Evaluation (for float and integer)
13257 //===----------------------------------------------------------------------===//
13260 class ComplexExprEvaluator
13261 : public ExprEvaluatorBase<ComplexExprEvaluator> {
13262 ComplexValue &Result;
13265 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
13266 : ExprEvaluatorBaseTy(info), Result(Result) {}
13268 bool Success(const APValue &V, const Expr *e) {
13273 bool ZeroInitialization(const Expr *E);
13275 //===--------------------------------------------------------------------===//
13277 //===--------------------------------------------------------------------===//
13279 bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
13280 bool VisitCastExpr(const CastExpr *E);
13281 bool VisitBinaryOperator(const BinaryOperator *E);
13282 bool VisitUnaryOperator(const UnaryOperator *E);
13283 bool VisitInitListExpr(const InitListExpr *E);
13285 } // end anonymous namespace
13287 static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
13289 assert(E->isRValue() && E->getType()->isAnyComplexType());
13290 return ComplexExprEvaluator(Info, Result).Visit(E);
13293 bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
13294 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
13295 if (ElemTy->isRealFloatingType()) {
13296 Result.makeComplexFloat();
13297 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy));
13298 Result.FloatReal = Zero;
13299 Result.FloatImag = Zero;
13301 Result.makeComplexInt();
13302 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy);
13303 Result.IntReal = Zero;
13304 Result.IntImag = Zero;
13309 bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
13310 const Expr* SubExpr = E->getSubExpr();
13312 if (SubExpr->getType()->isRealFloatingType()) {
13313 Result.makeComplexFloat();
13314 APFloat &Imag = Result.FloatImag;
13315 if (!EvaluateFloat(SubExpr, Imag, Info))
13318 Result.FloatReal = APFloat(Imag.getSemantics());
13321 assert(SubExpr->getType()->isIntegerType() &&
13322 "Unexpected imaginary literal.");
13324 Result.makeComplexInt();
13325 APSInt &Imag = Result.IntImag;
13326 if (!EvaluateInteger(SubExpr, Imag, Info))
13329 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
13334 bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
13336 switch (E->getCastKind()) {
13338 case CK_BaseToDerived:
13339 case CK_DerivedToBase:
13340 case CK_UncheckedDerivedToBase:
13343 case CK_ArrayToPointerDecay:
13344 case CK_FunctionToPointerDecay:
13345 case CK_NullToPointer:
13346 case CK_NullToMemberPointer:
13347 case CK_BaseToDerivedMemberPointer:
13348 case CK_DerivedToBaseMemberPointer:
13349 case CK_MemberPointerToBoolean:
13350 case CK_ReinterpretMemberPointer:
13351 case CK_ConstructorConversion:
13352 case CK_IntegralToPointer:
13353 case CK_PointerToIntegral:
13354 case CK_PointerToBoolean:
13356 case CK_VectorSplat:
13357 case CK_IntegralCast:
13358 case CK_BooleanToSignedIntegral:
13359 case CK_IntegralToBoolean:
13360 case CK_IntegralToFloating:
13361 case CK_FloatingToIntegral:
13362 case CK_FloatingToBoolean:
13363 case CK_FloatingCast:
13364 case CK_CPointerToObjCPointerCast:
13365 case CK_BlockPointerToObjCPointerCast:
13366 case CK_AnyPointerToBlockPointerCast:
13367 case CK_ObjCObjectLValueCast:
13368 case CK_FloatingComplexToReal:
13369 case CK_FloatingComplexToBoolean:
13370 case CK_IntegralComplexToReal:
13371 case CK_IntegralComplexToBoolean:
13372 case CK_ARCProduceObject:
13373 case CK_ARCConsumeObject:
13374 case CK_ARCReclaimReturnedObject:
13375 case CK_ARCExtendBlockObject:
13376 case CK_CopyAndAutoreleaseBlockObject:
13377 case CK_BuiltinFnToFnPtr:
13378 case CK_ZeroToOCLOpaqueType:
13379 case CK_NonAtomicToAtomic:
13380 case CK_AddressSpaceConversion:
13381 case CK_IntToOCLSampler:
13382 case CK_FixedPointCast:
13383 case CK_FixedPointToBoolean:
13384 case CK_FixedPointToIntegral:
13385 case CK_IntegralToFixedPoint:
13386 llvm_unreachable("invalid cast kind for complex value");
13388 case CK_LValueToRValue:
13389 case CK_AtomicToNonAtomic:
13391 case CK_LValueToRValueBitCast:
13392 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13395 case CK_LValueBitCast:
13396 case CK_UserDefinedConversion:
13399 case CK_FloatingRealToComplex: {
13400 APFloat &Real = Result.FloatReal;
13401 if (!EvaluateFloat(E->getSubExpr(), Real, Info))
13404 Result.makeComplexFloat();
13405 Result.FloatImag = APFloat(Real.getSemantics());
13409 case CK_FloatingComplexCast: {
13410 if (!Visit(E->getSubExpr()))
13413 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
13415 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
13417 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
13418 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
13421 case CK_FloatingComplexToIntegralComplex: {
13422 if (!Visit(E->getSubExpr()))
13425 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
13427 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
13428 Result.makeComplexInt();
13429 return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
13430 To, Result.IntReal) &&
13431 HandleFloatToIntCast(Info, E, From, Result.FloatImag,
13432 To, Result.IntImag);
13435 case CK_IntegralRealToComplex: {
13436 APSInt &Real = Result.IntReal;
13437 if (!EvaluateInteger(E->getSubExpr(), Real, Info))
13440 Result.makeComplexInt();
13441 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
13445 case CK_IntegralComplexCast: {
13446 if (!Visit(E->getSubExpr()))
13449 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
13451 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
13453 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
13454 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
13458 case CK_IntegralComplexToFloatingComplex: {
13459 if (!Visit(E->getSubExpr()))
13462 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
13464 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
13465 Result.makeComplexFloat();
13466 return HandleIntToFloatCast(Info, E, From, Result.IntReal,
13467 To, Result.FloatReal) &&
13468 HandleIntToFloatCast(Info, E, From, Result.IntImag,
13469 To, Result.FloatImag);
13473 llvm_unreachable("unknown cast resulting in complex value");
13476 bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
13477 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
13478 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13480 // Track whether the LHS or RHS is real at the type system level. When this is
13481 // the case we can simplify our evaluation strategy.
13482 bool LHSReal = false, RHSReal = false;
13485 if (E->getLHS()->getType()->isRealFloatingType()) {
13487 APFloat &Real = Result.FloatReal;
13488 LHSOK = EvaluateFloat(E->getLHS(), Real, Info);
13490 Result.makeComplexFloat();
13491 Result.FloatImag = APFloat(Real.getSemantics());
13494 LHSOK = Visit(E->getLHS());
13496 if (!LHSOK && !Info.noteFailure())
13500 if (E->getRHS()->getType()->isRealFloatingType()) {
13502 APFloat &Real = RHS.FloatReal;
13503 if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK)
13505 RHS.makeComplexFloat();
13506 RHS.FloatImag = APFloat(Real.getSemantics());
13507 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
13510 assert(!(LHSReal && RHSReal) &&
13511 "Cannot have both operands of a complex operation be real.");
13512 switch (E->getOpcode()) {
13513 default: return Error(E);
13515 if (Result.isComplexFloat()) {
13516 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
13517 APFloat::rmNearestTiesToEven);
13519 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
13521 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
13522 APFloat::rmNearestTiesToEven);
13524 Result.getComplexIntReal() += RHS.getComplexIntReal();
13525 Result.getComplexIntImag() += RHS.getComplexIntImag();
13529 if (Result.isComplexFloat()) {
13530 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
13531 APFloat::rmNearestTiesToEven);
13533 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
13534 Result.getComplexFloatImag().changeSign();
13535 } else if (!RHSReal) {
13536 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
13537 APFloat::rmNearestTiesToEven);
13540 Result.getComplexIntReal() -= RHS.getComplexIntReal();
13541 Result.getComplexIntImag() -= RHS.getComplexIntImag();
13545 if (Result.isComplexFloat()) {
13546 // This is an implementation of complex multiplication according to the
13547 // constraints laid out in C11 Annex G. The implementation uses the
13548 // following naming scheme:
13549 // (a + ib) * (c + id)
13550 ComplexValue LHS = Result;
13551 APFloat &A = LHS.getComplexFloatReal();
13552 APFloat &B = LHS.getComplexFloatImag();
13553 APFloat &C = RHS.getComplexFloatReal();
13554 APFloat &D = RHS.getComplexFloatImag();
13555 APFloat &ResR = Result.getComplexFloatReal();
13556 APFloat &ResI = Result.getComplexFloatImag();
13558 assert(!RHSReal && "Cannot have two real operands for a complex op!");
13561 } else if (RHSReal) {
13565 // In the fully general case, we need to handle NaNs and infinities
13567 APFloat AC = A * C;
13568 APFloat BD = B * D;
13569 APFloat AD = A * D;
13570 APFloat BC = B * C;
13573 if (ResR.isNaN() && ResI.isNaN()) {
13574 bool Recalc = false;
13575 if (A.isInfinity() || B.isInfinity()) {
13576 A = APFloat::copySign(
13577 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
13578 B = APFloat::copySign(
13579 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
13581 C = APFloat::copySign(APFloat(C.getSemantics()), C);
13583 D = APFloat::copySign(APFloat(D.getSemantics()), D);
13586 if (C.isInfinity() || D.isInfinity()) {
13587 C = APFloat::copySign(
13588 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
13589 D = APFloat::copySign(
13590 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
13592 A = APFloat::copySign(APFloat(A.getSemantics()), A);
13594 B = APFloat::copySign(APFloat(B.getSemantics()), B);
13597 if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
13598 AD.isInfinity() || BC.isInfinity())) {
13600 A = APFloat::copySign(APFloat(A.getSemantics()), A);
13602 B = APFloat::copySign(APFloat(B.getSemantics()), B);
13604 C = APFloat::copySign(APFloat(C.getSemantics()), C);
13606 D = APFloat::copySign(APFloat(D.getSemantics()), D);
13610 ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
13611 ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
13616 ComplexValue LHS = Result;
13617 Result.getComplexIntReal() =
13618 (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
13619 LHS.getComplexIntImag() * RHS.getComplexIntImag());
13620 Result.getComplexIntImag() =
13621 (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
13622 LHS.getComplexIntImag() * RHS.getComplexIntReal());
13626 if (Result.isComplexFloat()) {
13627 // This is an implementation of complex division according to the
13628 // constraints laid out in C11 Annex G. The implementation uses the
13629 // following naming scheme:
13630 // (a + ib) / (c + id)
13631 ComplexValue LHS = Result;
13632 APFloat &A = LHS.getComplexFloatReal();
13633 APFloat &B = LHS.getComplexFloatImag();
13634 APFloat &C = RHS.getComplexFloatReal();
13635 APFloat &D = RHS.getComplexFloatImag();
13636 APFloat &ResR = Result.getComplexFloatReal();
13637 APFloat &ResI = Result.getComplexFloatImag();
13643 // No real optimizations we can do here, stub out with zero.
13644 B = APFloat::getZero(A.getSemantics());
13647 APFloat MaxCD = maxnum(abs(C), abs(D));
13648 if (MaxCD.isFinite()) {
13649 DenomLogB = ilogb(MaxCD);
13650 C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven);
13651 D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven);
13653 APFloat Denom = C * C + D * D;
13654 ResR = scalbn((A * C + B * D) / Denom, -DenomLogB,
13655 APFloat::rmNearestTiesToEven);
13656 ResI = scalbn((B * C - A * D) / Denom, -DenomLogB,
13657 APFloat::rmNearestTiesToEven);
13658 if (ResR.isNaN() && ResI.isNaN()) {
13659 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
13660 ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A;
13661 ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B;
13662 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
13664 A = APFloat::copySign(
13665 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
13666 B = APFloat::copySign(
13667 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
13668 ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D);
13669 ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D);
13670 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
13671 C = APFloat::copySign(
13672 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
13673 D = APFloat::copySign(
13674 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
13675 ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D);
13676 ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D);
13681 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
13682 return Error(E, diag::note_expr_divide_by_zero);
13684 ComplexValue LHS = Result;
13685 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
13686 RHS.getComplexIntImag() * RHS.getComplexIntImag();
13687 Result.getComplexIntReal() =
13688 (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
13689 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
13690 Result.getComplexIntImag() =
13691 (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
13692 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
13700 bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13701 // Get the operand value into 'Result'.
13702 if (!Visit(E->getSubExpr()))
13705 switch (E->getOpcode()) {
13711 // The result is always just the subexpr.
13714 if (Result.isComplexFloat()) {
13715 Result.getComplexFloatReal().changeSign();
13716 Result.getComplexFloatImag().changeSign();
13719 Result.getComplexIntReal() = -Result.getComplexIntReal();
13720 Result.getComplexIntImag() = -Result.getComplexIntImag();
13724 if (Result.isComplexFloat())
13725 Result.getComplexFloatImag().changeSign();
13727 Result.getComplexIntImag() = -Result.getComplexIntImag();
13732 bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
13733 if (E->getNumInits() == 2) {
13734 if (E->getType()->isComplexType()) {
13735 Result.makeComplexFloat();
13736 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info))
13738 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info))
13741 Result.makeComplexInt();
13742 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info))
13744 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info))
13749 return ExprEvaluatorBaseTy::VisitInitListExpr(E);
13752 //===----------------------------------------------------------------------===//
13753 // Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
13754 // implicit conversion.
13755 //===----------------------------------------------------------------------===//
13758 class AtomicExprEvaluator :
13759 public ExprEvaluatorBase<AtomicExprEvaluator> {
13760 const LValue *This;
13763 AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
13764 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
13766 bool Success(const APValue &V, const Expr *E) {
13771 bool ZeroInitialization(const Expr *E) {
13772 ImplicitValueInitExpr VIE(
13773 E->getType()->castAs<AtomicType>()->getValueType());
13774 // For atomic-qualified class (and array) types in C++, initialize the
13775 // _Atomic-wrapped subobject directly, in-place.
13776 return This ? EvaluateInPlace(Result, Info, *This, &VIE)
13777 : Evaluate(Result, Info, &VIE);
13780 bool VisitCastExpr(const CastExpr *E) {
13781 switch (E->getCastKind()) {
13783 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13784 case CK_NonAtomicToAtomic:
13785 return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr())
13786 : Evaluate(Result, Info, E->getSubExpr());
13790 } // end anonymous namespace
13792 static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
13794 assert(E->isRValue() && E->getType()->isAtomicType());
13795 return AtomicExprEvaluator(Info, This, Result).Visit(E);
13798 //===----------------------------------------------------------------------===//
13799 // Void expression evaluation, primarily for a cast to void on the LHS of a
13801 //===----------------------------------------------------------------------===//
13804 class VoidExprEvaluator
13805 : public ExprEvaluatorBase<VoidExprEvaluator> {
13807 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
13809 bool Success(const APValue &V, const Expr *e) { return true; }
13811 bool ZeroInitialization(const Expr *E) { return true; }
13813 bool VisitCastExpr(const CastExpr *E) {
13814 switch (E->getCastKind()) {
13816 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13818 VisitIgnoredValue(E->getSubExpr());
13823 bool VisitCallExpr(const CallExpr *E) {
13824 switch (E->getBuiltinCallee()) {
13825 case Builtin::BI__assume:
13826 case Builtin::BI__builtin_assume:
13827 // The argument is not evaluated!
13830 case Builtin::BI__builtin_operator_delete:
13831 return HandleOperatorDeleteCall(Info, E);
13837 return ExprEvaluatorBaseTy::VisitCallExpr(E);
13840 bool VisitCXXDeleteExpr(const CXXDeleteExpr *E);
13842 } // end anonymous namespace
13844 bool VoidExprEvaluator::VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
13845 // We cannot speculatively evaluate a delete expression.
13846 if (Info.SpeculativeEvaluationDepth)
13849 FunctionDecl *OperatorDelete = E->getOperatorDelete();
13850 if (!OperatorDelete->isReplaceableGlobalAllocationFunction()) {
13851 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
13852 << isa<CXXMethodDecl>(OperatorDelete) << OperatorDelete;
13856 const Expr *Arg = E->getArgument();
13859 if (!EvaluatePointer(Arg, Pointer, Info))
13861 if (Pointer.Designator.Invalid)
13864 // Deleting a null pointer has no effect.
13865 if (Pointer.isNullPointer()) {
13866 // This is the only case where we need to produce an extension warning:
13867 // the only other way we can succeed is if we find a dynamic allocation,
13868 // and we will have warned when we allocated it in that case.
13869 if (!Info.getLangOpts().CPlusPlus20)
13870 Info.CCEDiag(E, diag::note_constexpr_new);
13874 Optional<DynAlloc *> Alloc = CheckDeleteKind(
13875 Info, E, Pointer, E->isArrayForm() ? DynAlloc::ArrayNew : DynAlloc::New);
13878 QualType AllocType = Pointer.Base.getDynamicAllocType();
13880 // For the non-array case, the designator must be empty if the static type
13881 // does not have a virtual destructor.
13882 if (!E->isArrayForm() && Pointer.Designator.Entries.size() != 0 &&
13883 !hasVirtualDestructor(Arg->getType()->getPointeeType())) {
13884 Info.FFDiag(E, diag::note_constexpr_delete_base_nonvirt_dtor)
13885 << Arg->getType()->getPointeeType() << AllocType;
13889 // For a class type with a virtual destructor, the selected operator delete
13890 // is the one looked up when building the destructor.
13891 if (!E->isArrayForm() && !E->isGlobalDelete()) {
13892 const FunctionDecl *VirtualDelete = getVirtualOperatorDelete(AllocType);
13893 if (VirtualDelete &&
13894 !VirtualDelete->isReplaceableGlobalAllocationFunction()) {
13895 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
13896 << isa<CXXMethodDecl>(VirtualDelete) << VirtualDelete;
13901 if (!HandleDestruction(Info, E->getExprLoc(), Pointer.getLValueBase(),
13902 (*Alloc)->Value, AllocType))
13905 if (!Info.HeapAllocs.erase(Pointer.Base.dyn_cast<DynamicAllocLValue>())) {
13906 // The element was already erased. This means the destructor call also
13907 // deleted the object.
13908 // FIXME: This probably results in undefined behavior before we get this
13909 // far, and should be diagnosed elsewhere first.
13910 Info.FFDiag(E, diag::note_constexpr_double_delete);
13917 static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
13918 assert(E->isRValue() && E->getType()->isVoidType());
13919 return VoidExprEvaluator(Info).Visit(E);
13922 //===----------------------------------------------------------------------===//
13923 // Top level Expr::EvaluateAsRValue method.
13924 //===----------------------------------------------------------------------===//
13926 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
13927 // In C, function designators are not lvalues, but we evaluate them as if they
13929 QualType T = E->getType();
13930 if (E->isGLValue() || T->isFunctionType()) {
13932 if (!EvaluateLValue(E, LV, Info))
13934 LV.moveInto(Result);
13935 } else if (T->isVectorType()) {
13936 if (!EvaluateVector(E, Result, Info))
13938 } else if (T->isIntegralOrEnumerationType()) {
13939 if (!IntExprEvaluator(Info, Result).Visit(E))
13941 } else if (T->hasPointerRepresentation()) {
13943 if (!EvaluatePointer(E, LV, Info))
13945 LV.moveInto(Result);
13946 } else if (T->isRealFloatingType()) {
13947 llvm::APFloat F(0.0);
13948 if (!EvaluateFloat(E, F, Info))
13950 Result = APValue(F);
13951 } else if (T->isAnyComplexType()) {
13953 if (!EvaluateComplex(E, C, Info))
13955 C.moveInto(Result);
13956 } else if (T->isFixedPointType()) {
13957 if (!FixedPointExprEvaluator(Info, Result).Visit(E)) return false;
13958 } else if (T->isMemberPointerType()) {
13960 if (!EvaluateMemberPointer(E, P, Info))
13962 P.moveInto(Result);
13964 } else if (T->isArrayType()) {
13967 Info.CurrentCall->createTemporary(E, T, false, LV);
13968 if (!EvaluateArray(E, LV, Value, Info))
13971 } else if (T->isRecordType()) {
13973 APValue &Value = Info.CurrentCall->createTemporary(E, T, false, LV);
13974 if (!EvaluateRecord(E, LV, Value, Info))
13977 } else if (T->isVoidType()) {
13978 if (!Info.getLangOpts().CPlusPlus11)
13979 Info.CCEDiag(E, diag::note_constexpr_nonliteral)
13981 if (!EvaluateVoid(E, Info))
13983 } else if (T->isAtomicType()) {
13984 QualType Unqual = T.getAtomicUnqualifiedType();
13985 if (Unqual->isArrayType() || Unqual->isRecordType()) {
13987 APValue &Value = Info.CurrentCall->createTemporary(E, Unqual, false, LV);
13988 if (!EvaluateAtomic(E, &LV, Value, Info))
13991 if (!EvaluateAtomic(E, nullptr, Result, Info))
13994 } else if (Info.getLangOpts().CPlusPlus11) {
13995 Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
13998 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
14005 /// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
14006 /// cases, the in-place evaluation is essential, since later initializers for
14007 /// an object can indirectly refer to subobjects which were initialized earlier.
14008 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
14009 const Expr *E, bool AllowNonLiteralTypes) {
14010 assert(!E->isValueDependent());
14012 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
14015 if (E->isRValue()) {
14016 // Evaluate arrays and record types in-place, so that later initializers can
14017 // refer to earlier-initialized members of the object.
14018 QualType T = E->getType();
14019 if (T->isArrayType())
14020 return EvaluateArray(E, This, Result, Info);
14021 else if (T->isRecordType())
14022 return EvaluateRecord(E, This, Result, Info);
14023 else if (T->isAtomicType()) {
14024 QualType Unqual = T.getAtomicUnqualifiedType();
14025 if (Unqual->isArrayType() || Unqual->isRecordType())
14026 return EvaluateAtomic(E, &This, Result, Info);
14030 // For any other type, in-place evaluation is unimportant.
14031 return Evaluate(Result, Info, E);
14034 /// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
14035 /// lvalue-to-rvalue cast if it is an lvalue.
14036 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
14037 if (Info.EnableNewConstInterp) {
14038 if (!Info.Ctx.getInterpContext().evaluateAsRValue(Info, E, Result))
14041 if (E->getType().isNull())
14044 if (!CheckLiteralType(Info, E))
14047 if (!::Evaluate(Result, Info, E))
14050 if (E->isGLValue()) {
14052 LV.setFrom(Info.Ctx, Result);
14053 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
14058 // Check this core constant expression is a constant expression.
14059 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result) &&
14060 CheckMemoryLeaks(Info);
14063 static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
14064 const ASTContext &Ctx, bool &IsConst) {
14065 // Fast-path evaluations of integer literals, since we sometimes see files
14066 // containing vast quantities of these.
14067 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) {
14068 Result.Val = APValue(APSInt(L->getValue(),
14069 L->getType()->isUnsignedIntegerType()));
14074 // This case should be rare, but we need to check it before we check on
14076 if (Exp->getType().isNull()) {
14081 // FIXME: Evaluating values of large array and record types can cause
14082 // performance problems. Only do so in C++11 for now.
14083 if (Exp->isRValue() && (Exp->getType()->isArrayType() ||
14084 Exp->getType()->isRecordType()) &&
14085 !Ctx.getLangOpts().CPlusPlus11) {
14092 static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
14093 Expr::SideEffectsKind SEK) {
14094 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
14095 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
14098 static bool EvaluateAsRValue(const Expr *E, Expr::EvalResult &Result,
14099 const ASTContext &Ctx, EvalInfo &Info) {
14101 if (FastEvaluateAsRValue(E, Result, Ctx, IsConst))
14104 return EvaluateAsRValue(Info, E, Result.Val);
14107 static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult,
14108 const ASTContext &Ctx,
14109 Expr::SideEffectsKind AllowSideEffects,
14111 if (!E->getType()->isIntegralOrEnumerationType())
14114 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info) ||
14115 !ExprResult.Val.isInt() ||
14116 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14122 static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult,
14123 const ASTContext &Ctx,
14124 Expr::SideEffectsKind AllowSideEffects,
14126 if (!E->getType()->isFixedPointType())
14129 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info))
14132 if (!ExprResult.Val.isFixedPoint() ||
14133 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14139 /// EvaluateAsRValue - Return true if this is a constant which we can fold using
14140 /// any crazy technique (that has nothing to do with language standards) that
14141 /// we want to. If this function returns true, it returns the folded constant
14142 /// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
14143 /// will be applied to the result.
14144 bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx,
14145 bool InConstantContext) const {
14146 assert(!isValueDependent() &&
14147 "Expression evaluator can't be called on a dependent expression.");
14148 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14149 Info.InConstantContext = InConstantContext;
14150 return ::EvaluateAsRValue(this, Result, Ctx, Info);
14153 bool Expr::EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx,
14154 bool InConstantContext) const {
14155 assert(!isValueDependent() &&
14156 "Expression evaluator can't be called on a dependent expression.");
14157 EvalResult Scratch;
14158 return EvaluateAsRValue(Scratch, Ctx, InConstantContext) &&
14159 HandleConversionToBool(Scratch.Val, Result);
14162 bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
14163 SideEffectsKind AllowSideEffects,
14164 bool InConstantContext) const {
14165 assert(!isValueDependent() &&
14166 "Expression evaluator can't be called on a dependent expression.");
14167 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14168 Info.InConstantContext = InConstantContext;
14169 return ::EvaluateAsInt(this, Result, Ctx, AllowSideEffects, Info);
14172 bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
14173 SideEffectsKind AllowSideEffects,
14174 bool InConstantContext) const {
14175 assert(!isValueDependent() &&
14176 "Expression evaluator can't be called on a dependent expression.");
14177 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14178 Info.InConstantContext = InConstantContext;
14179 return ::EvaluateAsFixedPoint(this, Result, Ctx, AllowSideEffects, Info);
14182 bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
14183 SideEffectsKind AllowSideEffects,
14184 bool InConstantContext) const {
14185 assert(!isValueDependent() &&
14186 "Expression evaluator can't be called on a dependent expression.");
14188 if (!getType()->isRealFloatingType())
14191 EvalResult ExprResult;
14192 if (!EvaluateAsRValue(ExprResult, Ctx, InConstantContext) ||
14193 !ExprResult.Val.isFloat() ||
14194 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14197 Result = ExprResult.Val.getFloat();
14201 bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx,
14202 bool InConstantContext) const {
14203 assert(!isValueDependent() &&
14204 "Expression evaluator can't be called on a dependent expression.");
14206 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
14207 Info.InConstantContext = InConstantContext;
14209 CheckedTemporaries CheckedTemps;
14210 if (!EvaluateLValue(this, LV, Info) || !Info.discardCleanups() ||
14211 Result.HasSideEffects ||
14212 !CheckLValueConstantExpression(Info, getExprLoc(),
14213 Ctx.getLValueReferenceType(getType()), LV,
14214 Expr::EvaluateForCodeGen, CheckedTemps))
14217 LV.moveInto(Result.Val);
14221 bool Expr::EvaluateAsConstantExpr(EvalResult &Result, ConstExprUsage Usage,
14222 const ASTContext &Ctx, bool InPlace) const {
14223 assert(!isValueDependent() &&
14224 "Expression evaluator can't be called on a dependent expression.");
14226 EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression;
14227 EvalInfo Info(Ctx, Result, EM);
14228 Info.InConstantContext = true;
14231 Info.setEvaluatingDecl(this, Result.Val);
14234 if (!::EvaluateInPlace(Result.Val, Info, LVal, this) ||
14235 Result.HasSideEffects)
14237 } else if (!::Evaluate(Result.Val, Info, this) || Result.HasSideEffects)
14240 if (!Info.discardCleanups())
14241 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
14243 return CheckConstantExpression(Info, getExprLoc(), getStorageType(Ctx, this),
14244 Result.Val, Usage) &&
14245 CheckMemoryLeaks(Info);
14248 bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
14250 SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
14251 assert(!isValueDependent() &&
14252 "Expression evaluator can't be called on a dependent expression.");
14254 // FIXME: Evaluating initializers for large array and record types can cause
14255 // performance problems. Only do so in C++11 for now.
14256 if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
14257 !Ctx.getLangOpts().CPlusPlus11)
14260 Expr::EvalStatus EStatus;
14261 EStatus.Diag = &Notes;
14263 EvalInfo Info(Ctx, EStatus, VD->isConstexpr()
14264 ? EvalInfo::EM_ConstantExpression
14265 : EvalInfo::EM_ConstantFold);
14266 Info.setEvaluatingDecl(VD, Value);
14267 Info.InConstantContext = true;
14269 SourceLocation DeclLoc = VD->getLocation();
14270 QualType DeclTy = VD->getType();
14272 if (Info.EnableNewConstInterp) {
14273 auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext();
14274 if (!InterpCtx.evaluateAsInitializer(Info, VD, Value))
14280 if (!EvaluateInPlace(Value, Info, LVal, this,
14281 /*AllowNonLiteralTypes=*/true) ||
14282 EStatus.HasSideEffects)
14285 // At this point, any lifetime-extended temporaries are completely
14287 Info.performLifetimeExtension();
14289 if (!Info.discardCleanups())
14290 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
14292 return CheckConstantExpression(Info, DeclLoc, DeclTy, Value) &&
14293 CheckMemoryLeaks(Info);
14296 bool VarDecl::evaluateDestruction(
14297 SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
14298 Expr::EvalStatus EStatus;
14299 EStatus.Diag = &Notes;
14301 // Make a copy of the value for the destructor to mutate, if we know it.
14302 // Otherwise, treat the value as default-initialized; if the destructor works
14303 // anyway, then the destruction is constant (and must be essentially empty).
14304 APValue DestroyedValue;
14305 if (getEvaluatedValue() && !getEvaluatedValue()->isAbsent())
14306 DestroyedValue = *getEvaluatedValue();
14307 else if (!getDefaultInitValue(getType(), DestroyedValue))
14310 EvalInfo Info(getASTContext(), EStatus, EvalInfo::EM_ConstantExpression);
14311 Info.setEvaluatingDecl(this, DestroyedValue,
14312 EvalInfo::EvaluatingDeclKind::Dtor);
14313 Info.InConstantContext = true;
14315 SourceLocation DeclLoc = getLocation();
14316 QualType DeclTy = getType();
14321 if (!HandleDestruction(Info, DeclLoc, LVal.Base, DestroyedValue, DeclTy) ||
14322 EStatus.HasSideEffects)
14325 if (!Info.discardCleanups())
14326 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
14328 ensureEvaluatedStmt()->HasConstantDestruction = true;
14332 /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
14333 /// constant folded, but discard the result.
14334 bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
14335 assert(!isValueDependent() &&
14336 "Expression evaluator can't be called on a dependent expression.");
14339 return EvaluateAsRValue(Result, Ctx, /* in constant context */ true) &&
14340 !hasUnacceptableSideEffect(Result, SEK);
14343 APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
14344 SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
14345 assert(!isValueDependent() &&
14346 "Expression evaluator can't be called on a dependent expression.");
14348 EvalResult EVResult;
14349 EVResult.Diag = Diag;
14350 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
14351 Info.InConstantContext = true;
14353 bool Result = ::EvaluateAsRValue(this, EVResult, Ctx, Info);
14355 assert(Result && "Could not evaluate expression");
14356 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer");
14358 return EVResult.Val.getInt();
14361 APSInt Expr::EvaluateKnownConstIntCheckOverflow(
14362 const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
14363 assert(!isValueDependent() &&
14364 "Expression evaluator can't be called on a dependent expression.");
14366 EvalResult EVResult;
14367 EVResult.Diag = Diag;
14368 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
14369 Info.InConstantContext = true;
14370 Info.CheckingForUndefinedBehavior = true;
14372 bool Result = ::EvaluateAsRValue(Info, this, EVResult.Val);
14374 assert(Result && "Could not evaluate expression");
14375 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer");
14377 return EVResult.Val.getInt();
14380 void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
14381 assert(!isValueDependent() &&
14382 "Expression evaluator can't be called on a dependent expression.");
14385 EvalResult EVResult;
14386 if (!FastEvaluateAsRValue(this, EVResult, Ctx, IsConst)) {
14387 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
14388 Info.CheckingForUndefinedBehavior = true;
14389 (void)::EvaluateAsRValue(Info, this, EVResult.Val);
14393 bool Expr::EvalResult::isGlobalLValue() const {
14394 assert(Val.isLValue());
14395 return IsGlobalLValue(Val.getLValueBase());
14399 /// isIntegerConstantExpr - this recursive routine will test if an expression is
14400 /// an integer constant expression.
14402 /// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
14405 // CheckICE - This function does the fundamental ICE checking: the returned
14406 // ICEDiag contains an ICEKind indicating whether the expression is an ICE,
14407 // and a (possibly null) SourceLocation indicating the location of the problem.
14409 // Note that to reduce code duplication, this helper does no evaluation
14410 // itself; the caller checks whether the expression is evaluatable, and
14411 // in the rare cases where CheckICE actually cares about the evaluated
14412 // value, it calls into Evaluate.
14417 /// This expression is an ICE.
14419 /// This expression is not an ICE, but if it isn't evaluated, it's
14420 /// a legal subexpression for an ICE. This return value is used to handle
14421 /// the comma operator in C99 mode, and non-constant subexpressions.
14422 IK_ICEIfUnevaluated,
14423 /// This expression is not an ICE, and is not a legal subexpression for one.
14429 SourceLocation Loc;
14431 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
14436 static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }
14438 static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }
14440 static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
14441 Expr::EvalResult EVResult;
14442 Expr::EvalStatus Status;
14443 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
14445 Info.InConstantContext = true;
14446 if (!::EvaluateAsRValue(E, EVResult, Ctx, Info) || EVResult.HasSideEffects ||
14447 !EVResult.Val.isInt())
14448 return ICEDiag(IK_NotICE, E->getBeginLoc());
14453 static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
14454 assert(!E->isValueDependent() && "Should not see value dependent exprs!");
14455 if (!E->getType()->isIntegralOrEnumerationType())
14456 return ICEDiag(IK_NotICE, E->getBeginLoc());
14458 switch (E->getStmtClass()) {
14459 #define ABSTRACT_STMT(Node)
14460 #define STMT(Node, Base) case Expr::Node##Class:
14461 #define EXPR(Node, Base)
14462 #include "clang/AST/StmtNodes.inc"
14463 case Expr::PredefinedExprClass:
14464 case Expr::FloatingLiteralClass:
14465 case Expr::ImaginaryLiteralClass:
14466 case Expr::StringLiteralClass:
14467 case Expr::ArraySubscriptExprClass:
14468 case Expr::MatrixSubscriptExprClass:
14469 case Expr::OMPArraySectionExprClass:
14470 case Expr::OMPArrayShapingExprClass:
14471 case Expr::OMPIteratorExprClass:
14472 case Expr::MemberExprClass:
14473 case Expr::CompoundAssignOperatorClass:
14474 case Expr::CompoundLiteralExprClass:
14475 case Expr::ExtVectorElementExprClass:
14476 case Expr::DesignatedInitExprClass:
14477 case Expr::ArrayInitLoopExprClass:
14478 case Expr::ArrayInitIndexExprClass:
14479 case Expr::NoInitExprClass:
14480 case Expr::DesignatedInitUpdateExprClass:
14481 case Expr::ImplicitValueInitExprClass:
14482 case Expr::ParenListExprClass:
14483 case Expr::VAArgExprClass:
14484 case Expr::AddrLabelExprClass:
14485 case Expr::StmtExprClass:
14486 case Expr::CXXMemberCallExprClass:
14487 case Expr::CUDAKernelCallExprClass:
14488 case Expr::CXXAddrspaceCastExprClass:
14489 case Expr::CXXDynamicCastExprClass:
14490 case Expr::CXXTypeidExprClass:
14491 case Expr::CXXUuidofExprClass:
14492 case Expr::MSPropertyRefExprClass:
14493 case Expr::MSPropertySubscriptExprClass:
14494 case Expr::CXXNullPtrLiteralExprClass:
14495 case Expr::UserDefinedLiteralClass:
14496 case Expr::CXXThisExprClass:
14497 case Expr::CXXThrowExprClass:
14498 case Expr::CXXNewExprClass:
14499 case Expr::CXXDeleteExprClass:
14500 case Expr::CXXPseudoDestructorExprClass:
14501 case Expr::UnresolvedLookupExprClass:
14502 case Expr::TypoExprClass:
14503 case Expr::RecoveryExprClass:
14504 case Expr::DependentScopeDeclRefExprClass:
14505 case Expr::CXXConstructExprClass:
14506 case Expr::CXXInheritedCtorInitExprClass:
14507 case Expr::CXXStdInitializerListExprClass:
14508 case Expr::CXXBindTemporaryExprClass:
14509 case Expr::ExprWithCleanupsClass:
14510 case Expr::CXXTemporaryObjectExprClass:
14511 case Expr::CXXUnresolvedConstructExprClass:
14512 case Expr::CXXDependentScopeMemberExprClass:
14513 case Expr::UnresolvedMemberExprClass:
14514 case Expr::ObjCStringLiteralClass:
14515 case Expr::ObjCBoxedExprClass:
14516 case Expr::ObjCArrayLiteralClass:
14517 case Expr::ObjCDictionaryLiteralClass:
14518 case Expr::ObjCEncodeExprClass:
14519 case Expr::ObjCMessageExprClass:
14520 case Expr::ObjCSelectorExprClass:
14521 case Expr::ObjCProtocolExprClass:
14522 case Expr::ObjCIvarRefExprClass:
14523 case Expr::ObjCPropertyRefExprClass:
14524 case Expr::ObjCSubscriptRefExprClass:
14525 case Expr::ObjCIsaExprClass:
14526 case Expr::ObjCAvailabilityCheckExprClass:
14527 case Expr::ShuffleVectorExprClass:
14528 case Expr::ConvertVectorExprClass:
14529 case Expr::BlockExprClass:
14530 case Expr::NoStmtClass:
14531 case Expr::OpaqueValueExprClass:
14532 case Expr::PackExpansionExprClass:
14533 case Expr::SubstNonTypeTemplateParmPackExprClass:
14534 case Expr::FunctionParmPackExprClass:
14535 case Expr::AsTypeExprClass:
14536 case Expr::ObjCIndirectCopyRestoreExprClass:
14537 case Expr::MaterializeTemporaryExprClass:
14538 case Expr::PseudoObjectExprClass:
14539 case Expr::AtomicExprClass:
14540 case Expr::LambdaExprClass:
14541 case Expr::CXXFoldExprClass:
14542 case Expr::CoawaitExprClass:
14543 case Expr::DependentCoawaitExprClass:
14544 case Expr::CoyieldExprClass:
14545 return ICEDiag(IK_NotICE, E->getBeginLoc());
14547 case Expr::InitListExprClass: {
14548 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
14549 // form "T x = { a };" is equivalent to "T x = a;".
14550 // Unless we're initializing a reference, T is a scalar as it is known to be
14551 // of integral or enumeration type.
14553 if (cast<InitListExpr>(E)->getNumInits() == 1)
14554 return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx);
14555 return ICEDiag(IK_NotICE, E->getBeginLoc());
14558 case Expr::SizeOfPackExprClass:
14559 case Expr::GNUNullExprClass:
14560 case Expr::SourceLocExprClass:
14563 case Expr::SubstNonTypeTemplateParmExprClass:
14565 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
14567 case Expr::ConstantExprClass:
14568 return CheckICE(cast<ConstantExpr>(E)->getSubExpr(), Ctx);
14570 case Expr::ParenExprClass:
14571 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
14572 case Expr::GenericSelectionExprClass:
14573 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
14574 case Expr::IntegerLiteralClass:
14575 case Expr::FixedPointLiteralClass:
14576 case Expr::CharacterLiteralClass:
14577 case Expr::ObjCBoolLiteralExprClass:
14578 case Expr::CXXBoolLiteralExprClass:
14579 case Expr::CXXScalarValueInitExprClass:
14580 case Expr::TypeTraitExprClass:
14581 case Expr::ConceptSpecializationExprClass:
14582 case Expr::RequiresExprClass:
14583 case Expr::ArrayTypeTraitExprClass:
14584 case Expr::ExpressionTraitExprClass:
14585 case Expr::CXXNoexceptExprClass:
14587 case Expr::CallExprClass:
14588 case Expr::CXXOperatorCallExprClass: {
14589 // C99 6.6/3 allows function calls within unevaluated subexpressions of
14590 // constant expressions, but they can never be ICEs because an ICE cannot
14591 // contain an operand of (pointer to) function type.
14592 const CallExpr *CE = cast<CallExpr>(E);
14593 if (CE->getBuiltinCallee())
14594 return CheckEvalInICE(E, Ctx);
14595 return ICEDiag(IK_NotICE, E->getBeginLoc());
14597 case Expr::CXXRewrittenBinaryOperatorClass:
14598 return CheckICE(cast<CXXRewrittenBinaryOperator>(E)->getSemanticForm(),
14600 case Expr::DeclRefExprClass: {
14601 if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl()))
14603 const ValueDecl *D = cast<DeclRefExpr>(E)->getDecl();
14604 if (Ctx.getLangOpts().CPlusPlus &&
14605 D && IsConstNonVolatile(D->getType())) {
14606 // Parameter variables are never constants. Without this check,
14607 // getAnyInitializer() can find a default argument, which leads
14609 if (isa<ParmVarDecl>(D))
14610 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
14613 // A variable of non-volatile const-qualified integral or enumeration
14614 // type initialized by an ICE can be used in ICEs.
14615 if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) {
14616 if (!Dcl->getType()->isIntegralOrEnumerationType())
14617 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
14620 // Look for a declaration of this variable that has an initializer, and
14621 // check whether it is an ICE.
14622 if (Dcl->getAnyInitializer(VD) && VD->checkInitIsICE())
14625 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
14628 return ICEDiag(IK_NotICE, E->getBeginLoc());
14630 case Expr::UnaryOperatorClass: {
14631 const UnaryOperator *Exp = cast<UnaryOperator>(E);
14632 switch (Exp->getOpcode()) {
14640 // C99 6.6/3 allows increment and decrement within unevaluated
14641 // subexpressions of constant expressions, but they can never be ICEs
14642 // because an ICE cannot contain an lvalue operand.
14643 return ICEDiag(IK_NotICE, E->getBeginLoc());
14651 return CheckICE(Exp->getSubExpr(), Ctx);
14653 llvm_unreachable("invalid unary operator class");
14655 case Expr::OffsetOfExprClass: {
14656 // Note that per C99, offsetof must be an ICE. And AFAIK, using
14657 // EvaluateAsRValue matches the proposed gcc behavior for cases like
14658 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect
14659 // compliance: we should warn earlier for offsetof expressions with
14660 // array subscripts that aren't ICEs, and if the array subscripts
14661 // are ICEs, the value of the offsetof must be an integer constant.
14662 return CheckEvalInICE(E, Ctx);
14664 case Expr::UnaryExprOrTypeTraitExprClass: {
14665 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
14666 if ((Exp->getKind() == UETT_SizeOf) &&
14667 Exp->getTypeOfArgument()->isVariableArrayType())
14668 return ICEDiag(IK_NotICE, E->getBeginLoc());
14671 case Expr::BinaryOperatorClass: {
14672 const BinaryOperator *Exp = cast<BinaryOperator>(E);
14673 switch (Exp->getOpcode()) {
14687 // C99 6.6/3 allows assignments within unevaluated subexpressions of
14688 // constant expressions, but they can never be ICEs because an ICE cannot
14689 // contain an lvalue operand.
14690 return ICEDiag(IK_NotICE, E->getBeginLoc());
14710 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
14711 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
14712 if (Exp->getOpcode() == BO_Div ||
14713 Exp->getOpcode() == BO_Rem) {
14714 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
14715 // we don't evaluate one.
14716 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
14717 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
14719 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
14720 if (REval.isSigned() && REval.isAllOnesValue()) {
14721 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
14722 if (LEval.isMinSignedValue())
14723 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
14727 if (Exp->getOpcode() == BO_Comma) {
14728 if (Ctx.getLangOpts().C99) {
14729 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
14730 // if it isn't evaluated.
14731 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
14732 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
14734 // In both C89 and C++, commas in ICEs are illegal.
14735 return ICEDiag(IK_NotICE, E->getBeginLoc());
14738 return Worst(LHSResult, RHSResult);
14742 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
14743 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
14744 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
14745 // Rare case where the RHS has a comma "side-effect"; we need
14746 // to actually check the condition to see whether the side
14747 // with the comma is evaluated.
14748 if ((Exp->getOpcode() == BO_LAnd) !=
14749 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
14754 return Worst(LHSResult, RHSResult);
14757 llvm_unreachable("invalid binary operator kind");
14759 case Expr::ImplicitCastExprClass:
14760 case Expr::CStyleCastExprClass:
14761 case Expr::CXXFunctionalCastExprClass:
14762 case Expr::CXXStaticCastExprClass:
14763 case Expr::CXXReinterpretCastExprClass:
14764 case Expr::CXXConstCastExprClass:
14765 case Expr::ObjCBridgedCastExprClass: {
14766 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
14767 if (isa<ExplicitCastExpr>(E)) {
14768 if (const FloatingLiteral *FL
14769 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
14770 unsigned DestWidth = Ctx.getIntWidth(E->getType());
14771 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
14772 APSInt IgnoredVal(DestWidth, !DestSigned);
14774 // If the value does not fit in the destination type, the behavior is
14775 // undefined, so we are not required to treat it as a constant
14777 if (FL->getValue().convertToInteger(IgnoredVal,
14778 llvm::APFloat::rmTowardZero,
14779 &Ignored) & APFloat::opInvalidOp)
14780 return ICEDiag(IK_NotICE, E->getBeginLoc());
14784 switch (cast<CastExpr>(E)->getCastKind()) {
14785 case CK_LValueToRValue:
14786 case CK_AtomicToNonAtomic:
14787 case CK_NonAtomicToAtomic:
14789 case CK_IntegralToBoolean:
14790 case CK_IntegralCast:
14791 return CheckICE(SubExpr, Ctx);
14793 return ICEDiag(IK_NotICE, E->getBeginLoc());
14796 case Expr::BinaryConditionalOperatorClass: {
14797 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
14798 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
14799 if (CommonResult.Kind == IK_NotICE) return CommonResult;
14800 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
14801 if (FalseResult.Kind == IK_NotICE) return FalseResult;
14802 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
14803 if (FalseResult.Kind == IK_ICEIfUnevaluated &&
14804 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
14805 return FalseResult;
14807 case Expr::ConditionalOperatorClass: {
14808 const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
14809 // If the condition (ignoring parens) is a __builtin_constant_p call,
14810 // then only the true side is actually considered in an integer constant
14811 // expression, and it is fully evaluated. This is an important GNU
14812 // extension. See GCC PR38377 for discussion.
14813 if (const CallExpr *CallCE
14814 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
14815 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
14816 return CheckEvalInICE(E, Ctx);
14817 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
14818 if (CondResult.Kind == IK_NotICE)
14821 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
14822 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
14824 if (TrueResult.Kind == IK_NotICE)
14826 if (FalseResult.Kind == IK_NotICE)
14827 return FalseResult;
14828 if (CondResult.Kind == IK_ICEIfUnevaluated)
14830 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
14832 // Rare case where the diagnostics depend on which side is evaluated
14833 // Note that if we get here, CondResult is 0, and at least one of
14834 // TrueResult and FalseResult is non-zero.
14835 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
14836 return FalseResult;
14839 case Expr::CXXDefaultArgExprClass:
14840 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
14841 case Expr::CXXDefaultInitExprClass:
14842 return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx);
14843 case Expr::ChooseExprClass: {
14844 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
14846 case Expr::BuiltinBitCastExprClass: {
14847 if (!checkBitCastConstexprEligibility(nullptr, Ctx, cast<CastExpr>(E)))
14848 return ICEDiag(IK_NotICE, E->getBeginLoc());
14849 return CheckICE(cast<CastExpr>(E)->getSubExpr(), Ctx);
14853 llvm_unreachable("Invalid StmtClass!");
14856 /// Evaluate an expression as a C++11 integral constant expression.
14857 static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
14859 llvm::APSInt *Value,
14860 SourceLocation *Loc) {
14861 if (!E->getType()->isIntegralOrUnscopedEnumerationType()) {
14862 if (Loc) *Loc = E->getExprLoc();
14867 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc))
14870 if (!Result.isInt()) {
14871 if (Loc) *Loc = E->getExprLoc();
14875 if (Value) *Value = Result.getInt();
14879 bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
14880 SourceLocation *Loc) const {
14881 assert(!isValueDependent() &&
14882 "Expression evaluator can't be called on a dependent expression.");
14884 if (Ctx.getLangOpts().CPlusPlus11)
14885 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc);
14887 ICEDiag D = CheckICE(this, Ctx);
14888 if (D.Kind != IK_ICE) {
14889 if (Loc) *Loc = D.Loc;
14895 bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, const ASTContext &Ctx,
14896 SourceLocation *Loc, bool isEvaluated) const {
14897 assert(!isValueDependent() &&
14898 "Expression evaluator can't be called on a dependent expression.");
14900 if (Ctx.getLangOpts().CPlusPlus11)
14901 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc);
14903 if (!isIntegerConstantExpr(Ctx, Loc))
14906 // The only possible side-effects here are due to UB discovered in the
14907 // evaluation (for instance, INT_MAX + 1). In such a case, we are still
14908 // required to treat the expression as an ICE, so we produce the folded
14910 EvalResult ExprResult;
14911 Expr::EvalStatus Status;
14912 EvalInfo Info(Ctx, Status, EvalInfo::EM_IgnoreSideEffects);
14913 Info.InConstantContext = true;
14915 if (!::EvaluateAsInt(this, ExprResult, Ctx, SE_AllowSideEffects, Info))
14916 llvm_unreachable("ICE cannot be evaluated!");
14918 Value = ExprResult.Val.getInt();
14922 bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
14923 assert(!isValueDependent() &&
14924 "Expression evaluator can't be called on a dependent expression.");
14926 return CheckICE(this, Ctx).Kind == IK_ICE;
14929 bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
14930 SourceLocation *Loc) const {
14931 assert(!isValueDependent() &&
14932 "Expression evaluator can't be called on a dependent expression.");
14934 // We support this checking in C++98 mode in order to diagnose compatibility
14936 assert(Ctx.getLangOpts().CPlusPlus);
14938 // Build evaluation settings.
14939 Expr::EvalStatus Status;
14940 SmallVector<PartialDiagnosticAt, 8> Diags;
14941 Status.Diag = &Diags;
14942 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
14946 ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch) &&
14947 // FIXME: We don't produce a diagnostic for this, but the callers that
14948 // call us on arbitrary full-expressions should generally not care.
14949 Info.discardCleanups() && !Status.HasSideEffects;
14951 if (!Diags.empty()) {
14952 IsConstExpr = false;
14953 if (Loc) *Loc = Diags[0].first;
14954 } else if (!IsConstExpr) {
14955 // FIXME: This shouldn't happen.
14956 if (Loc) *Loc = getExprLoc();
14959 return IsConstExpr;
14962 bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
14963 const FunctionDecl *Callee,
14964 ArrayRef<const Expr*> Args,
14965 const Expr *This) const {
14966 assert(!isValueDependent() &&
14967 "Expression evaluator can't be called on a dependent expression.");
14969 Expr::EvalStatus Status;
14970 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
14971 Info.InConstantContext = true;
14974 const LValue *ThisPtr = nullptr;
14977 auto *MD = dyn_cast<CXXMethodDecl>(Callee);
14978 assert(MD && "Don't provide `this` for non-methods.");
14979 assert(!MD->isStatic() && "Don't provide `this` for static methods.");
14981 if (!This->isValueDependent() &&
14982 EvaluateObjectArgument(Info, This, ThisVal) &&
14983 !Info.EvalStatus.HasSideEffects)
14984 ThisPtr = &ThisVal;
14986 // Ignore any side-effects from a failed evaluation. This is safe because
14987 // they can't interfere with any other argument evaluation.
14988 Info.EvalStatus.HasSideEffects = false;
14991 ArgVector ArgValues(Args.size());
14992 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
14994 if ((*I)->isValueDependent() ||
14995 !Evaluate(ArgValues[I - Args.begin()], Info, *I) ||
14996 Info.EvalStatus.HasSideEffects)
14997 // If evaluation fails, throw away the argument entirely.
14998 ArgValues[I - Args.begin()] = APValue();
15000 // Ignore any side-effects from a failed evaluation. This is safe because
15001 // they can't interfere with any other argument evaluation.
15002 Info.EvalStatus.HasSideEffects = false;
15005 // Parameter cleanups happen in the caller and are not part of this
15007 Info.discardCleanups();
15008 Info.EvalStatus.HasSideEffects = false;
15010 // Build fake call to Callee.
15011 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr,
15013 // FIXME: Missing ExprWithCleanups in enable_if conditions?
15014 FullExpressionRAII Scope(Info);
15015 return Evaluate(Value, Info, this) && Scope.destroy() &&
15016 !Info.EvalStatus.HasSideEffects;
15019 bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
15021 PartialDiagnosticAt> &Diags) {
15022 // FIXME: It would be useful to check constexpr function templates, but at the
15023 // moment the constant expression evaluator cannot cope with the non-rigorous
15024 // ASTs which we build for dependent expressions.
15025 if (FD->isDependentContext())
15028 // Bail out if a constexpr constructor has an initializer that contains an
15029 // error. We deliberately don't produce a diagnostic, as we have produced a
15030 // relevant diagnostic when parsing the error initializer.
15031 if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(FD)) {
15032 for (const auto *InitExpr : Ctor->inits()) {
15033 if (InitExpr->getInit() && InitExpr->getInit()->containsErrors())
15037 Expr::EvalStatus Status;
15038 Status.Diag = &Diags;
15040 EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression);
15041 Info.InConstantContext = true;
15042 Info.CheckingPotentialConstantExpression = true;
15044 // The constexpr VM attempts to compile all methods to bytecode here.
15045 if (Info.EnableNewConstInterp) {
15046 Info.Ctx.getInterpContext().isPotentialConstantExpr(Info, FD);
15047 return Diags.empty();
15050 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
15051 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;
15053 // Fabricate an arbitrary expression on the stack and pretend that it
15054 // is a temporary being used as the 'this' pointer.
15056 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
15057 This.set({&VIE, Info.CurrentCall->Index});
15059 ArrayRef<const Expr*> Args;
15062 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
15063 // Evaluate the call as a constant initializer, to allow the construction
15064 // of objects of non-literal types.
15065 Info.setEvaluatingDecl(This.getLValueBase(), Scratch);
15066 HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch);
15068 SourceLocation Loc = FD->getLocation();
15069 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : nullptr,
15070 Args, FD->getBody(), Info, Scratch, nullptr);
15073 return Diags.empty();
15076 bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
15077 const FunctionDecl *FD,
15079 PartialDiagnosticAt> &Diags) {
15080 assert(!E->isValueDependent() &&
15081 "Expression evaluator can't be called on a dependent expression.");
15083 Expr::EvalStatus Status;
15084 Status.Diag = &Diags;
15086 EvalInfo Info(FD->getASTContext(), Status,
15087 EvalInfo::EM_ConstantExpressionUnevaluated);
15088 Info.InConstantContext = true;
15089 Info.CheckingPotentialConstantExpression = true;
15091 // Fabricate a call stack frame to give the arguments a plausible cover story.
15092 ArrayRef<const Expr*> Args;
15093 ArgVector ArgValues(0);
15094 bool Success = EvaluateArgs(Args, ArgValues, Info, FD);
15097 "Failed to set up arguments for potential constant evaluation");
15098 CallStackFrame Frame(Info, SourceLocation(), FD, nullptr, ArgValues.data());
15100 APValue ResultScratch;
15101 Evaluate(ResultScratch, Info, E);
15102 return Diags.empty();
15105 bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
15106 unsigned Type) const {
15107 if (!getType()->isPointerType())
15110 Expr::EvalStatus Status;
15111 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
15112 return tryEvaluateBuiltinObjectSize(this, Type, Info, Result);