1 //===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the Expr constant evaluator.
12 // Constant expression evaluation produces four main results:
14 // * A success/failure flag indicating whether constant folding was successful.
15 // This is the 'bool' return value used by most of the code in this file. A
16 // 'false' return value indicates that constant folding has failed, and any
17 // appropriate diagnostic has already been produced.
19 // * An evaluated result, valid only if constant folding has not failed.
21 // * A flag indicating if evaluation encountered (unevaluated) side-effects.
22 // These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
23 // where it is possible to determine the evaluated result regardless.
25 // * A set of notes indicating why the evaluation was not a constant expression
26 // (under the C++11 / C++1y rules only, at the moment), or, if folding failed
27 // too, why the expression could not be folded.
29 // If we are checking for a potential constant expression, failure to constant
30 // fold a potential constant sub-expression will be indicated by a 'false'
31 // return value (the expression could not be folded) and no diagnostic (the
32 // expression is not necessarily non-constant).
34 //===----------------------------------------------------------------------===//
36 #include "clang/AST/APValue.h"
37 #include "clang/AST/ASTContext.h"
38 #include "clang/AST/ASTDiagnostic.h"
39 #include "clang/AST/ASTLambda.h"
40 #include "clang/AST/CharUnits.h"
41 #include "clang/AST/Expr.h"
42 #include "clang/AST/RecordLayout.h"
43 #include "clang/AST/StmtVisitor.h"
44 #include "clang/AST/TypeLoc.h"
45 #include "clang/Basic/Builtins.h"
46 #include "clang/Basic/TargetInfo.h"
47 #include "llvm/Support/raw_ostream.h"
51 using namespace clang;
55 static bool IsGlobalLValue(APValue::LValueBase B);
59 struct CallStackFrame;
62 static QualType getType(APValue::LValueBase B) {
63 if (!B) return QualType();
64 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>())
67 const Expr *Base = B.get<const Expr*>();
69 // For a materialized temporary, the type of the temporary we materialized
70 // may not be the type of the expression.
71 if (const MaterializeTemporaryExpr *MTE =
72 dyn_cast<MaterializeTemporaryExpr>(Base)) {
73 SmallVector<const Expr *, 2> CommaLHSs;
74 SmallVector<SubobjectAdjustment, 2> Adjustments;
75 const Expr *Temp = MTE->GetTemporaryExpr();
76 const Expr *Inner = Temp->skipRValueSubobjectAdjustments(CommaLHSs,
78 // Keep any cv-qualifiers from the reference if we generated a temporary
79 // for it directly. Otherwise use the type after adjustment.
80 if (!Adjustments.empty())
81 return Inner->getType();
84 return Base->getType();
87 /// Get an LValue path entry, which is known to not be an array index, as a
88 /// field or base class.
90 APValue::BaseOrMemberType getAsBaseOrMember(APValue::LValuePathEntry E) {
91 APValue::BaseOrMemberType Value;
92 Value.setFromOpaqueValue(E.BaseOrMember);
96 /// Get an LValue path entry, which is known to not be an array index, as a
97 /// field declaration.
98 static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
99 return dyn_cast<FieldDecl>(getAsBaseOrMember(E).getPointer());
101 /// Get an LValue path entry, which is known to not be an array index, as a
102 /// base class declaration.
103 static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
104 return dyn_cast<CXXRecordDecl>(getAsBaseOrMember(E).getPointer());
106 /// Determine whether this LValue path entry for a base class names a virtual
108 static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
109 return getAsBaseOrMember(E).getInt();
112 /// Given a CallExpr, try to get the alloc_size attribute. May return null.
113 static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) {
114 const FunctionDecl *Callee = CE->getDirectCallee();
115 return Callee ? Callee->getAttr<AllocSizeAttr>() : nullptr;
118 /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr.
119 /// This will look through a single cast.
121 /// Returns null if we couldn't unwrap a function with alloc_size.
122 static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) {
123 if (!E->getType()->isPointerType())
126 E = E->IgnoreParens();
127 // If we're doing a variable assignment from e.g. malloc(N), there will
128 // probably be a cast of some kind. Ignore it.
129 if (const auto *Cast = dyn_cast<CastExpr>(E))
130 E = Cast->getSubExpr()->IgnoreParens();
132 if (const auto *CE = dyn_cast<CallExpr>(E))
133 return getAllocSizeAttr(CE) ? CE : nullptr;
137 /// Determines whether or not the given Base contains a call to a function
138 /// with the alloc_size attribute.
139 static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) {
140 const auto *E = Base.dyn_cast<const Expr *>();
141 return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E);
144 /// Determines if an LValue with the given LValueBase will have an unsized
145 /// array in its designator.
146 /// Find the path length and type of the most-derived subobject in the given
147 /// path, and find the size of the containing array, if any.
149 findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
150 ArrayRef<APValue::LValuePathEntry> Path,
151 uint64_t &ArraySize, QualType &Type, bool &IsArray) {
152 // This only accepts LValueBases from APValues, and APValues don't support
153 // arrays that lack size info.
154 assert(!isBaseAnAllocSizeCall(Base) &&
155 "Unsized arrays shouldn't appear here");
156 unsigned MostDerivedLength = 0;
157 Type = getType(Base);
159 for (unsigned I = 0, N = Path.size(); I != N; ++I) {
160 if (Type->isArrayType()) {
161 const ConstantArrayType *CAT =
162 cast<ConstantArrayType>(Ctx.getAsArrayType(Type));
163 Type = CAT->getElementType();
164 ArraySize = CAT->getSize().getZExtValue();
165 MostDerivedLength = I + 1;
167 } else if (Type->isAnyComplexType()) {
168 const ComplexType *CT = Type->castAs<ComplexType>();
169 Type = CT->getElementType();
171 MostDerivedLength = I + 1;
173 } else if (const FieldDecl *FD = getAsField(Path[I])) {
174 Type = FD->getType();
176 MostDerivedLength = I + 1;
179 // Path[I] describes a base class.
184 return MostDerivedLength;
187 // The order of this enum is important for diagnostics.
188 enum CheckSubobjectKind {
189 CSK_Base, CSK_Derived, CSK_Field, CSK_ArrayToPointer, CSK_ArrayIndex,
190 CSK_This, CSK_Real, CSK_Imag
193 /// A path from a glvalue to a subobject of that glvalue.
194 struct SubobjectDesignator {
195 /// True if the subobject was named in a manner not supported by C++11. Such
196 /// lvalues can still be folded, but they are not core constant expressions
197 /// and we cannot perform lvalue-to-rvalue conversions on them.
198 unsigned Invalid : 1;
200 /// Is this a pointer one past the end of an object?
201 unsigned IsOnePastTheEnd : 1;
203 /// Indicator of whether the first entry is an unsized array.
204 unsigned FirstEntryIsAnUnsizedArray : 1;
206 /// Indicator of whether the most-derived object is an array element.
207 unsigned MostDerivedIsArrayElement : 1;
209 /// The length of the path to the most-derived object of which this is a
211 unsigned MostDerivedPathLength : 28;
213 /// The size of the array of which the most-derived object is an element.
214 /// This will always be 0 if the most-derived object is not an array
215 /// element. 0 is not an indicator of whether or not the most-derived object
216 /// is an array, however, because 0-length arrays are allowed.
218 /// If the current array is an unsized array, the value of this is
220 uint64_t MostDerivedArraySize;
222 /// The type of the most derived object referred to by this address.
223 QualType MostDerivedType;
225 typedef APValue::LValuePathEntry PathEntry;
227 /// The entries on the path from the glvalue to the designated subobject.
228 SmallVector<PathEntry, 8> Entries;
230 SubobjectDesignator() : Invalid(true) {}
232 explicit SubobjectDesignator(QualType T)
233 : Invalid(false), IsOnePastTheEnd(false),
234 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
235 MostDerivedPathLength(0), MostDerivedArraySize(0),
236 MostDerivedType(T) {}
238 SubobjectDesignator(ASTContext &Ctx, const APValue &V)
239 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
240 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
241 MostDerivedPathLength(0), MostDerivedArraySize(0) {
242 assert(V.isLValue() && "Non-LValue used to make an LValue designator?");
244 IsOnePastTheEnd = V.isLValueOnePastTheEnd();
245 ArrayRef<PathEntry> VEntries = V.getLValuePath();
246 Entries.insert(Entries.end(), VEntries.begin(), VEntries.end());
247 if (V.getLValueBase()) {
248 bool IsArray = false;
249 MostDerivedPathLength = findMostDerivedSubobject(
250 Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize,
251 MostDerivedType, IsArray);
252 MostDerivedIsArrayElement = IsArray;
262 /// Determine whether the most derived subobject is an array without a
264 bool isMostDerivedAnUnsizedArray() const {
265 assert(!Invalid && "Calling this makes no sense on invalid designators");
266 return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
269 /// Determine what the most derived array's size is. Results in an assertion
270 /// failure if the most derived array lacks a size.
271 uint64_t getMostDerivedArraySize() const {
272 assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size");
273 return MostDerivedArraySize;
276 /// Determine whether this is a one-past-the-end pointer.
277 bool isOnePastTheEnd() const {
281 if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement &&
282 Entries[MostDerivedPathLength - 1].ArrayIndex == MostDerivedArraySize)
287 /// Check that this refers to a valid subobject.
288 bool isValidSubobject() const {
291 return !isOnePastTheEnd();
293 /// Check that this refers to a valid subobject, and if not, produce a
294 /// relevant diagnostic and set the designator as invalid.
295 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);
297 /// Update this designator to refer to the first element within this array.
298 void addArrayUnchecked(const ConstantArrayType *CAT) {
300 Entry.ArrayIndex = 0;
301 Entries.push_back(Entry);
303 // This is a most-derived object.
304 MostDerivedType = CAT->getElementType();
305 MostDerivedIsArrayElement = true;
306 MostDerivedArraySize = CAT->getSize().getZExtValue();
307 MostDerivedPathLength = Entries.size();
309 /// Update this designator to refer to the first element within the array of
310 /// elements of type T. This is an array of unknown size.
311 void addUnsizedArrayUnchecked(QualType ElemTy) {
313 Entry.ArrayIndex = 0;
314 Entries.push_back(Entry);
316 MostDerivedType = ElemTy;
317 MostDerivedIsArrayElement = true;
318 // The value in MostDerivedArraySize is undefined in this case. So, set it
319 // to an arbitrary value that's likely to loudly break things if it's
321 MostDerivedArraySize = std::numeric_limits<uint64_t>::max() / 2;
322 MostDerivedPathLength = Entries.size();
324 /// Update this designator to refer to the given base or member of this
326 void addDeclUnchecked(const Decl *D, bool Virtual = false) {
328 APValue::BaseOrMemberType Value(D, Virtual);
329 Entry.BaseOrMember = Value.getOpaqueValue();
330 Entries.push_back(Entry);
332 // If this isn't a base class, it's a new most-derived object.
333 if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
334 MostDerivedType = FD->getType();
335 MostDerivedIsArrayElement = false;
336 MostDerivedArraySize = 0;
337 MostDerivedPathLength = Entries.size();
340 /// Update this designator to refer to the given complex component.
341 void addComplexUnchecked(QualType EltTy, bool Imag) {
343 Entry.ArrayIndex = Imag;
344 Entries.push_back(Entry);
346 // This is technically a most-derived object, though in practice this
347 // is unlikely to matter.
348 MostDerivedType = EltTy;
349 MostDerivedIsArrayElement = true;
350 MostDerivedArraySize = 2;
351 MostDerivedPathLength = Entries.size();
353 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E,
355 /// Add N to the address of this subobject.
356 void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
357 if (Invalid || !N) return;
358 uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue();
359 if (isMostDerivedAnUnsizedArray()) {
360 // Can't verify -- trust that the user is doing the right thing (or if
361 // not, trust that the caller will catch the bad behavior).
362 // FIXME: Should we reject if this overflows, at least?
363 Entries.back().ArrayIndex += TruncatedN;
367 // [expr.add]p4: For the purposes of these operators, a pointer to a
368 // nonarray object behaves the same as a pointer to the first element of
369 // an array of length one with the type of the object as its element type.
370 bool IsArray = MostDerivedPathLength == Entries.size() &&
371 MostDerivedIsArrayElement;
372 uint64_t ArrayIndex =
373 IsArray ? Entries.back().ArrayIndex : (uint64_t)IsOnePastTheEnd;
375 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
377 if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
378 // Calculate the actual index in a wide enough type, so we can include
380 N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65));
381 (llvm::APInt&)N += ArrayIndex;
382 assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index");
383 diagnosePointerArithmetic(Info, E, N);
388 ArrayIndex += TruncatedN;
389 assert(ArrayIndex <= ArraySize &&
390 "bounds check succeeded for out-of-bounds index");
393 Entries.back().ArrayIndex = ArrayIndex;
395 IsOnePastTheEnd = (ArrayIndex != 0);
399 /// A stack frame in the constexpr call stack.
400 struct CallStackFrame {
403 /// Parent - The caller of this stack frame.
404 CallStackFrame *Caller;
406 /// Callee - The function which was called.
407 const FunctionDecl *Callee;
409 /// This - The binding for the this pointer in this call, if any.
412 /// Arguments - Parameter bindings for this function call, indexed by
413 /// parameters' function scope indices.
416 // Note that we intentionally use std::map here so that references to
417 // values are stable.
418 typedef std::map<const void*, APValue> MapTy;
419 typedef MapTy::const_iterator temp_iterator;
420 /// Temporaries - Temporary lvalues materialized within this stack frame.
423 /// CallLoc - The location of the call expression for this call.
424 SourceLocation CallLoc;
426 /// Index - The call index of this call.
429 // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact
430 // on the overall stack usage of deeply-recursing constexpr evaluataions.
431 // (We should cache this map rather than recomputing it repeatedly.)
432 // But let's try this and see how it goes; we can look into caching the map
433 // as a later change.
435 /// LambdaCaptureFields - Mapping from captured variables/this to
436 /// corresponding data members in the closure class.
437 llvm::DenseMap<const VarDecl *, FieldDecl *> LambdaCaptureFields;
438 FieldDecl *LambdaThisCaptureField;
440 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
441 const FunctionDecl *Callee, const LValue *This,
445 APValue *getTemporary(const void *Key) {
446 MapTy::iterator I = Temporaries.find(Key);
447 return I == Temporaries.end() ? nullptr : &I->second;
449 APValue &createTemporary(const void *Key, bool IsLifetimeExtended);
452 /// Temporarily override 'this'.
453 class ThisOverrideRAII {
455 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
456 : Frame(Frame), OldThis(Frame.This) {
458 Frame.This = NewThis;
460 ~ThisOverrideRAII() {
461 Frame.This = OldThis;
464 CallStackFrame &Frame;
465 const LValue *OldThis;
468 /// A partial diagnostic which we might know in advance that we are not going
470 class OptionalDiagnostic {
471 PartialDiagnostic *Diag;
474 explicit OptionalDiagnostic(PartialDiagnostic *Diag = nullptr)
478 OptionalDiagnostic &operator<<(const T &v) {
484 OptionalDiagnostic &operator<<(const APSInt &I) {
486 SmallVector<char, 32> Buffer;
488 *Diag << StringRef(Buffer.data(), Buffer.size());
493 OptionalDiagnostic &operator<<(const APFloat &F) {
495 // FIXME: Force the precision of the source value down so we don't
496 // print digits which are usually useless (we don't really care here if
497 // we truncate a digit by accident in edge cases). Ideally,
498 // APFloat::toString would automatically print the shortest
499 // representation which rounds to the correct value, but it's a bit
500 // tricky to implement.
502 llvm::APFloat::semanticsPrecision(F.getSemantics());
503 precision = (precision * 59 + 195) / 196;
504 SmallVector<char, 32> Buffer;
505 F.toString(Buffer, precision);
506 *Diag << StringRef(Buffer.data(), Buffer.size());
512 /// A cleanup, and a flag indicating whether it is lifetime-extended.
514 llvm::PointerIntPair<APValue*, 1, bool> Value;
517 Cleanup(APValue *Val, bool IsLifetimeExtended)
518 : Value(Val, IsLifetimeExtended) {}
520 bool isLifetimeExtended() const { return Value.getInt(); }
522 *Value.getPointer() = APValue();
526 /// EvalInfo - This is a private struct used by the evaluator to capture
527 /// information about a subexpression as it is folded. It retains information
528 /// about the AST context, but also maintains information about the folded
531 /// If an expression could be evaluated, it is still possible it is not a C
532 /// "integer constant expression" or constant expression. If not, this struct
533 /// captures information about how and why not.
535 /// One bit of information passed *into* the request for constant folding
536 /// indicates whether the subexpression is "evaluated" or not according to C
537 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
538 /// evaluate the expression regardless of what the RHS is, but C only allows
539 /// certain things in certain situations.
540 struct LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) EvalInfo {
543 /// EvalStatus - Contains information about the evaluation.
544 Expr::EvalStatus &EvalStatus;
546 /// CurrentCall - The top of the constexpr call stack.
547 CallStackFrame *CurrentCall;
549 /// CallStackDepth - The number of calls in the call stack right now.
550 unsigned CallStackDepth;
552 /// NextCallIndex - The next call index to assign.
553 unsigned NextCallIndex;
555 /// StepsLeft - The remaining number of evaluation steps we're permitted
556 /// to perform. This is essentially a limit for the number of statements
557 /// we will evaluate.
560 /// BottomFrame - The frame in which evaluation started. This must be
561 /// initialized after CurrentCall and CallStackDepth.
562 CallStackFrame BottomFrame;
564 /// A stack of values whose lifetimes end at the end of some surrounding
565 /// evaluation frame.
566 llvm::SmallVector<Cleanup, 16> CleanupStack;
568 /// EvaluatingDecl - This is the declaration whose initializer is being
569 /// evaluated, if any.
570 APValue::LValueBase EvaluatingDecl;
572 /// EvaluatingDeclValue - This is the value being constructed for the
573 /// declaration whose initializer is being evaluated, if any.
574 APValue *EvaluatingDeclValue;
576 /// The current array initialization index, if we're performing array
578 uint64_t ArrayInitIndex = -1;
580 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
581 /// notes attached to it will also be stored, otherwise they will not be.
582 bool HasActiveDiagnostic;
584 /// \brief Have we emitted a diagnostic explaining why we couldn't constant
585 /// fold (not just why it's not strictly a constant expression)?
586 bool HasFoldFailureDiagnostic;
588 /// \brief Whether or not we're currently speculatively evaluating.
589 bool IsSpeculativelyEvaluating;
591 enum EvaluationMode {
592 /// Evaluate as a constant expression. Stop if we find that the expression
593 /// is not a constant expression.
594 EM_ConstantExpression,
596 /// Evaluate as a potential constant expression. Keep going if we hit a
597 /// construct that we can't evaluate yet (because we don't yet know the
598 /// value of something) but stop if we hit something that could never be
599 /// a constant expression.
600 EM_PotentialConstantExpression,
602 /// Fold the expression to a constant. Stop if we hit a side-effect that
606 /// Evaluate the expression looking for integer overflow and similar
607 /// issues. Don't worry about side-effects, and try to visit all
609 EM_EvaluateForOverflow,
611 /// Evaluate in any way we know how. Don't worry about side-effects that
612 /// can't be modeled.
613 EM_IgnoreSideEffects,
615 /// Evaluate as a constant expression. Stop if we find that the expression
616 /// is not a constant expression. Some expressions can be retried in the
617 /// optimizer if we don't constant fold them here, but in an unevaluated
618 /// context we try to fold them immediately since the optimizer never
619 /// gets a chance to look at it.
620 EM_ConstantExpressionUnevaluated,
622 /// Evaluate as a potential constant expression. Keep going if we hit a
623 /// construct that we can't evaluate yet (because we don't yet know the
624 /// value of something) but stop if we hit something that could never be
625 /// a constant expression. Some expressions can be retried in the
626 /// optimizer if we don't constant fold them here, but in an unevaluated
627 /// context we try to fold them immediately since the optimizer never
628 /// gets a chance to look at it.
629 EM_PotentialConstantExpressionUnevaluated,
631 /// Evaluate as a constant expression. In certain scenarios, if:
632 /// - we find a MemberExpr with a base that can't be evaluated, or
633 /// - we find a variable initialized with a call to a function that has
634 /// the alloc_size attribute on it
635 /// then we may consider evaluation to have succeeded.
637 /// In either case, the LValue returned shall have an invalid base; in the
638 /// former, the base will be the invalid MemberExpr, in the latter, the
639 /// base will be either the alloc_size CallExpr or a CastExpr wrapping
644 /// Are we checking whether the expression is a potential constant
646 bool checkingPotentialConstantExpression() const {
647 return EvalMode == EM_PotentialConstantExpression ||
648 EvalMode == EM_PotentialConstantExpressionUnevaluated;
651 /// Are we checking an expression for overflow?
652 // FIXME: We should check for any kind of undefined or suspicious behavior
653 // in such constructs, not just overflow.
654 bool checkingForOverflow() { return EvalMode == EM_EvaluateForOverflow; }
656 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
657 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
658 CallStackDepth(0), NextCallIndex(1),
659 StepsLeft(getLangOpts().ConstexprStepLimit),
660 BottomFrame(*this, SourceLocation(), nullptr, nullptr, nullptr),
661 EvaluatingDecl((const ValueDecl *)nullptr),
662 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
663 HasFoldFailureDiagnostic(false), IsSpeculativelyEvaluating(false),
666 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value) {
667 EvaluatingDecl = Base;
668 EvaluatingDeclValue = &Value;
671 const LangOptions &getLangOpts() const { return Ctx.getLangOpts(); }
673 bool CheckCallLimit(SourceLocation Loc) {
674 // Don't perform any constexpr calls (other than the call we're checking)
675 // when checking a potential constant expression.
676 if (checkingPotentialConstantExpression() && CallStackDepth > 1)
678 if (NextCallIndex == 0) {
679 // NextCallIndex has wrapped around.
680 FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
683 if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
685 FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded)
686 << getLangOpts().ConstexprCallDepth;
690 CallStackFrame *getCallFrame(unsigned CallIndex) {
691 assert(CallIndex && "no call index in getCallFrame");
692 // We will eventually hit BottomFrame, which has Index 1, so Frame can't
693 // be null in this loop.
694 CallStackFrame *Frame = CurrentCall;
695 while (Frame->Index > CallIndex)
696 Frame = Frame->Caller;
697 return (Frame->Index == CallIndex) ? Frame : nullptr;
700 bool nextStep(const Stmt *S) {
702 FFDiag(S->getLocStart(), diag::note_constexpr_step_limit_exceeded);
710 /// Add a diagnostic to the diagnostics list.
711 PartialDiagnostic &addDiag(SourceLocation Loc, diag::kind DiagId) {
712 PartialDiagnostic PD(DiagId, Ctx.getDiagAllocator());
713 EvalStatus.Diag->push_back(std::make_pair(Loc, PD));
714 return EvalStatus.Diag->back().second;
717 /// Add notes containing a call stack to the current point of evaluation.
718 void addCallStack(unsigned Limit);
721 OptionalDiagnostic Diag(SourceLocation Loc, diag::kind DiagId,
722 unsigned ExtraNotes, bool IsCCEDiag) {
724 if (EvalStatus.Diag) {
725 // If we have a prior diagnostic, it will be noting that the expression
726 // isn't a constant expression. This diagnostic is more important,
727 // unless we require this evaluation to produce a constant expression.
729 // FIXME: We might want to show both diagnostics to the user in
730 // EM_ConstantFold mode.
731 if (!EvalStatus.Diag->empty()) {
733 case EM_ConstantFold:
734 case EM_IgnoreSideEffects:
735 case EM_EvaluateForOverflow:
736 if (!HasFoldFailureDiagnostic)
738 // We've already failed to fold something. Keep that diagnostic.
740 case EM_ConstantExpression:
741 case EM_PotentialConstantExpression:
742 case EM_ConstantExpressionUnevaluated:
743 case EM_PotentialConstantExpressionUnevaluated:
745 HasActiveDiagnostic = false;
746 return OptionalDiagnostic();
750 unsigned CallStackNotes = CallStackDepth - 1;
751 unsigned Limit = Ctx.getDiagnostics().getConstexprBacktraceLimit();
753 CallStackNotes = std::min(CallStackNotes, Limit + 1);
754 if (checkingPotentialConstantExpression())
757 HasActiveDiagnostic = true;
758 HasFoldFailureDiagnostic = !IsCCEDiag;
759 EvalStatus.Diag->clear();
760 EvalStatus.Diag->reserve(1 + ExtraNotes + CallStackNotes);
761 addDiag(Loc, DiagId);
762 if (!checkingPotentialConstantExpression())
764 return OptionalDiagnostic(&(*EvalStatus.Diag)[0].second);
766 HasActiveDiagnostic = false;
767 return OptionalDiagnostic();
770 // Diagnose that the evaluation could not be folded (FF => FoldFailure)
772 FFDiag(SourceLocation Loc,
773 diag::kind DiagId = diag::note_invalid_subexpr_in_const_expr,
774 unsigned ExtraNotes = 0) {
775 return Diag(Loc, DiagId, ExtraNotes, false);
778 OptionalDiagnostic FFDiag(const Expr *E, diag::kind DiagId
779 = diag::note_invalid_subexpr_in_const_expr,
780 unsigned ExtraNotes = 0) {
782 return Diag(E->getExprLoc(), DiagId, ExtraNotes, /*IsCCEDiag*/false);
783 HasActiveDiagnostic = false;
784 return OptionalDiagnostic();
787 /// Diagnose that the evaluation does not produce a C++11 core constant
790 /// FIXME: Stop evaluating if we're in EM_ConstantExpression or
791 /// EM_PotentialConstantExpression mode and we produce one of these.
792 OptionalDiagnostic CCEDiag(SourceLocation Loc, diag::kind DiagId
793 = diag::note_invalid_subexpr_in_const_expr,
794 unsigned ExtraNotes = 0) {
795 // Don't override a previous diagnostic. Don't bother collecting
796 // diagnostics if we're evaluating for overflow.
797 if (!EvalStatus.Diag || !EvalStatus.Diag->empty()) {
798 HasActiveDiagnostic = false;
799 return OptionalDiagnostic();
801 return Diag(Loc, DiagId, ExtraNotes, true);
803 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind DiagId
804 = diag::note_invalid_subexpr_in_const_expr,
805 unsigned ExtraNotes = 0) {
806 return CCEDiag(E->getExprLoc(), DiagId, ExtraNotes);
808 /// Add a note to a prior diagnostic.
809 OptionalDiagnostic Note(SourceLocation Loc, diag::kind DiagId) {
810 if (!HasActiveDiagnostic)
811 return OptionalDiagnostic();
812 return OptionalDiagnostic(&addDiag(Loc, DiagId));
815 /// Add a stack of notes to a prior diagnostic.
816 void addNotes(ArrayRef<PartialDiagnosticAt> Diags) {
817 if (HasActiveDiagnostic) {
818 EvalStatus.Diag->insert(EvalStatus.Diag->end(),
819 Diags.begin(), Diags.end());
823 /// Should we continue evaluation after encountering a side-effect that we
825 bool keepEvaluatingAfterSideEffect() {
827 case EM_PotentialConstantExpression:
828 case EM_PotentialConstantExpressionUnevaluated:
829 case EM_EvaluateForOverflow:
830 case EM_IgnoreSideEffects:
833 case EM_ConstantExpression:
834 case EM_ConstantExpressionUnevaluated:
835 case EM_ConstantFold:
839 llvm_unreachable("Missed EvalMode case");
842 /// Note that we have had a side-effect, and determine whether we should
844 bool noteSideEffect() {
845 EvalStatus.HasSideEffects = true;
846 return keepEvaluatingAfterSideEffect();
849 /// Should we continue evaluation after encountering undefined behavior?
850 bool keepEvaluatingAfterUndefinedBehavior() {
852 case EM_EvaluateForOverflow:
853 case EM_IgnoreSideEffects:
854 case EM_ConstantFold:
858 case EM_PotentialConstantExpression:
859 case EM_PotentialConstantExpressionUnevaluated:
860 case EM_ConstantExpression:
861 case EM_ConstantExpressionUnevaluated:
864 llvm_unreachable("Missed EvalMode case");
867 /// Note that we hit something that was technically undefined behavior, but
868 /// that we can evaluate past it (such as signed overflow or floating-point
869 /// division by zero.)
870 bool noteUndefinedBehavior() {
871 EvalStatus.HasUndefinedBehavior = true;
872 return keepEvaluatingAfterUndefinedBehavior();
875 /// Should we continue evaluation as much as possible after encountering a
876 /// construct which can't be reduced to a value?
877 bool keepEvaluatingAfterFailure() {
882 case EM_PotentialConstantExpression:
883 case EM_PotentialConstantExpressionUnevaluated:
884 case EM_EvaluateForOverflow:
887 case EM_ConstantExpression:
888 case EM_ConstantExpressionUnevaluated:
889 case EM_ConstantFold:
890 case EM_IgnoreSideEffects:
894 llvm_unreachable("Missed EvalMode case");
897 /// Notes that we failed to evaluate an expression that other expressions
898 /// directly depend on, and determine if we should keep evaluating. This
899 /// should only be called if we actually intend to keep evaluating.
901 /// Call noteSideEffect() instead if we may be able to ignore the value that
902 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
904 /// (Foo(), 1) // use noteSideEffect
905 /// (Foo() || true) // use noteSideEffect
906 /// Foo() + 1 // use noteFailure
907 LLVM_NODISCARD bool noteFailure() {
908 // Failure when evaluating some expression often means there is some
909 // subexpression whose evaluation was skipped. Therefore, (because we
910 // don't track whether we skipped an expression when unwinding after an
911 // evaluation failure) every evaluation failure that bubbles up from a
912 // subexpression implies that a side-effect has potentially happened. We
913 // skip setting the HasSideEffects flag to true until we decide to
914 // continue evaluating after that point, which happens here.
915 bool KeepGoing = keepEvaluatingAfterFailure();
916 EvalStatus.HasSideEffects |= KeepGoing;
920 class ArrayInitLoopIndex {
925 ArrayInitLoopIndex(EvalInfo &Info)
926 : Info(Info), OuterIndex(Info.ArrayInitIndex) {
927 Info.ArrayInitIndex = 0;
929 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
931 operator uint64_t&() { return Info.ArrayInitIndex; }
935 /// Object used to treat all foldable expressions as constant expressions.
936 struct FoldConstant {
939 bool HadNoPriorDiags;
940 EvalInfo::EvaluationMode OldMode;
942 explicit FoldConstant(EvalInfo &Info, bool Enabled)
945 HadNoPriorDiags(Info.EvalStatus.Diag &&
946 Info.EvalStatus.Diag->empty() &&
947 !Info.EvalStatus.HasSideEffects),
948 OldMode(Info.EvalMode) {
950 (Info.EvalMode == EvalInfo::EM_ConstantExpression ||
951 Info.EvalMode == EvalInfo::EM_ConstantExpressionUnevaluated))
952 Info.EvalMode = EvalInfo::EM_ConstantFold;
954 void keepDiagnostics() { Enabled = false; }
956 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
957 !Info.EvalStatus.HasSideEffects)
958 Info.EvalStatus.Diag->clear();
959 Info.EvalMode = OldMode;
963 /// RAII object used to treat the current evaluation as the correct pointer
964 /// offset fold for the current EvalMode
965 struct FoldOffsetRAII {
967 EvalInfo::EvaluationMode OldMode;
968 explicit FoldOffsetRAII(EvalInfo &Info)
969 : Info(Info), OldMode(Info.EvalMode) {
970 if (!Info.checkingPotentialConstantExpression())
971 Info.EvalMode = EvalInfo::EM_OffsetFold;
974 ~FoldOffsetRAII() { Info.EvalMode = OldMode; }
977 /// RAII object used to optionally suppress diagnostics and side-effects from
978 /// a speculative evaluation.
979 class SpeculativeEvaluationRAII {
980 /// Pair of EvalInfo, and a bit that stores whether or not we were
981 /// speculatively evaluating when we created this RAII.
982 llvm::PointerIntPair<EvalInfo *, 1, bool> InfoAndOldSpecEval;
983 Expr::EvalStatus Old;
985 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
986 InfoAndOldSpecEval = Other.InfoAndOldSpecEval;
988 Other.InfoAndOldSpecEval.setPointer(nullptr);
991 void maybeRestoreState() {
992 EvalInfo *Info = InfoAndOldSpecEval.getPointer();
996 Info->EvalStatus = Old;
997 Info->IsSpeculativelyEvaluating = InfoAndOldSpecEval.getInt();
1001 SpeculativeEvaluationRAII() = default;
1003 SpeculativeEvaluationRAII(
1004 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
1005 : InfoAndOldSpecEval(&Info, Info.IsSpeculativelyEvaluating),
1006 Old(Info.EvalStatus) {
1007 Info.EvalStatus.Diag = NewDiag;
1008 Info.IsSpeculativelyEvaluating = true;
1011 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
1012 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
1013 moveFromAndCancel(std::move(Other));
1016 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
1017 maybeRestoreState();
1018 moveFromAndCancel(std::move(Other));
1022 ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1025 /// RAII object wrapping a full-expression or block scope, and handling
1026 /// the ending of the lifetime of temporaries created within it.
1027 template<bool IsFullExpression>
1030 unsigned OldStackSize;
1032 ScopeRAII(EvalInfo &Info)
1033 : Info(Info), OldStackSize(Info.CleanupStack.size()) {}
1035 // Body moved to a static method to encourage the compiler to inline away
1036 // instances of this class.
1037 cleanup(Info, OldStackSize);
1040 static void cleanup(EvalInfo &Info, unsigned OldStackSize) {
1041 unsigned NewEnd = OldStackSize;
1042 for (unsigned I = OldStackSize, N = Info.CleanupStack.size();
1044 if (IsFullExpression && Info.CleanupStack[I].isLifetimeExtended()) {
1045 // Full-expression cleanup of a lifetime-extended temporary: nothing
1046 // to do, just move this cleanup to the right place in the stack.
1047 std::swap(Info.CleanupStack[I], Info.CleanupStack[NewEnd]);
1050 // End the lifetime of the object.
1051 Info.CleanupStack[I].endLifetime();
1054 Info.CleanupStack.erase(Info.CleanupStack.begin() + NewEnd,
1055 Info.CleanupStack.end());
1058 typedef ScopeRAII<false> BlockScopeRAII;
1059 typedef ScopeRAII<true> FullExpressionRAII;
1062 bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1063 CheckSubobjectKind CSK) {
1066 if (isOnePastTheEnd()) {
1067 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
1075 void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1078 // If we're complaining, we must be able to statically determine the size of
1079 // the most derived array.
1080 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1081 Info.CCEDiag(E, diag::note_constexpr_array_index)
1083 << static_cast<unsigned>(getMostDerivedArraySize());
1085 Info.CCEDiag(E, diag::note_constexpr_array_index)
1086 << N << /*non-array*/ 1;
1090 CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
1091 const FunctionDecl *Callee, const LValue *This,
1093 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1094 Arguments(Arguments), CallLoc(CallLoc), Index(Info.NextCallIndex++) {
1095 Info.CurrentCall = this;
1096 ++Info.CallStackDepth;
1099 CallStackFrame::~CallStackFrame() {
1100 assert(Info.CurrentCall == this && "calls retired out of order");
1101 --Info.CallStackDepth;
1102 Info.CurrentCall = Caller;
1105 APValue &CallStackFrame::createTemporary(const void *Key,
1106 bool IsLifetimeExtended) {
1107 APValue &Result = Temporaries[Key];
1108 assert(Result.isUninit() && "temporary created multiple times");
1109 Info.CleanupStack.push_back(Cleanup(&Result, IsLifetimeExtended));
1113 static void describeCall(CallStackFrame *Frame, raw_ostream &Out);
1115 void EvalInfo::addCallStack(unsigned Limit) {
1116 // Determine which calls to skip, if any.
1117 unsigned ActiveCalls = CallStackDepth - 1;
1118 unsigned SkipStart = ActiveCalls, SkipEnd = SkipStart;
1119 if (Limit && Limit < ActiveCalls) {
1120 SkipStart = Limit / 2 + Limit % 2;
1121 SkipEnd = ActiveCalls - Limit / 2;
1124 // Walk the call stack and add the diagnostics.
1125 unsigned CallIdx = 0;
1126 for (CallStackFrame *Frame = CurrentCall; Frame != &BottomFrame;
1127 Frame = Frame->Caller, ++CallIdx) {
1129 if (CallIdx >= SkipStart && CallIdx < SkipEnd) {
1130 if (CallIdx == SkipStart) {
1131 // Note that we're skipping calls.
1132 addDiag(Frame->CallLoc, diag::note_constexpr_calls_suppressed)
1133 << unsigned(ActiveCalls - Limit);
1138 // Use a different note for an inheriting constructor, because from the
1139 // user's perspective it's not really a function at all.
1140 if (auto *CD = dyn_cast_or_null<CXXConstructorDecl>(Frame->Callee)) {
1141 if (CD->isInheritingConstructor()) {
1142 addDiag(Frame->CallLoc, diag::note_constexpr_inherited_ctor_call_here)
1148 SmallVector<char, 128> Buffer;
1149 llvm::raw_svector_ostream Out(Buffer);
1150 describeCall(Frame, Out);
1151 addDiag(Frame->CallLoc, diag::note_constexpr_call_here) << Out.str();
1156 struct ComplexValue {
1161 APSInt IntReal, IntImag;
1162 APFloat FloatReal, FloatImag;
1164 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1166 void makeComplexFloat() { IsInt = false; }
1167 bool isComplexFloat() const { return !IsInt; }
1168 APFloat &getComplexFloatReal() { return FloatReal; }
1169 APFloat &getComplexFloatImag() { return FloatImag; }
1171 void makeComplexInt() { IsInt = true; }
1172 bool isComplexInt() const { return IsInt; }
1173 APSInt &getComplexIntReal() { return IntReal; }
1174 APSInt &getComplexIntImag() { return IntImag; }
1176 void moveInto(APValue &v) const {
1177 if (isComplexFloat())
1178 v = APValue(FloatReal, FloatImag);
1180 v = APValue(IntReal, IntImag);
1182 void setFrom(const APValue &v) {
1183 assert(v.isComplexFloat() || v.isComplexInt());
1184 if (v.isComplexFloat()) {
1186 FloatReal = v.getComplexFloatReal();
1187 FloatImag = v.getComplexFloatImag();
1190 IntReal = v.getComplexIntReal();
1191 IntImag = v.getComplexIntImag();
1197 APValue::LValueBase Base;
1199 unsigned InvalidBase : 1;
1200 unsigned CallIndex : 31;
1201 SubobjectDesignator Designator;
1204 const APValue::LValueBase getLValueBase() const { return Base; }
1205 CharUnits &getLValueOffset() { return Offset; }
1206 const CharUnits &getLValueOffset() const { return Offset; }
1207 unsigned getLValueCallIndex() const { return CallIndex; }
1208 SubobjectDesignator &getLValueDesignator() { return Designator; }
1209 const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1210 bool isNullPointer() const { return IsNullPtr;}
1212 void moveInto(APValue &V) const {
1213 if (Designator.Invalid)
1214 V = APValue(Base, Offset, APValue::NoLValuePath(), CallIndex,
1217 assert(!InvalidBase && "APValues can't handle invalid LValue bases");
1218 assert(!Designator.FirstEntryIsAnUnsizedArray &&
1219 "Unsized array with a valid base?");
1220 V = APValue(Base, Offset, Designator.Entries,
1221 Designator.IsOnePastTheEnd, CallIndex, IsNullPtr);
1224 void setFrom(ASTContext &Ctx, const APValue &V) {
1225 assert(V.isLValue() && "Setting LValue from a non-LValue?");
1226 Base = V.getLValueBase();
1227 Offset = V.getLValueOffset();
1228 InvalidBase = false;
1229 CallIndex = V.getLValueCallIndex();
1230 Designator = SubobjectDesignator(Ctx, V);
1231 IsNullPtr = V.isNullPointer();
1234 void set(APValue::LValueBase B, unsigned I = 0, bool BInvalid = false) {
1236 // We only allow a few types of invalid bases. Enforce that here.
1238 const auto *E = B.get<const Expr *>();
1239 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&
1240 "Unexpected type of invalid base");
1245 Offset = CharUnits::fromQuantity(0);
1246 InvalidBase = BInvalid;
1248 Designator = SubobjectDesignator(getType(B));
1252 void setNull(QualType PointerTy, uint64_t TargetVal) {
1253 Base = (Expr *)nullptr;
1254 Offset = CharUnits::fromQuantity(TargetVal);
1255 InvalidBase = false;
1257 Designator = SubobjectDesignator(PointerTy->getPointeeType());
1261 void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1265 // Check that this LValue is not based on a null pointer. If it is, produce
1266 // a diagnostic and mark the designator as invalid.
1267 bool checkNullPointer(EvalInfo &Info, const Expr *E,
1268 CheckSubobjectKind CSK) {
1269 if (Designator.Invalid)
1272 Info.CCEDiag(E, diag::note_constexpr_null_subobject)
1274 Designator.setInvalid();
1280 // Check this LValue refers to an object. If not, set the designator to be
1281 // invalid and emit a diagnostic.
1282 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1283 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1284 Designator.checkSubobject(Info, E, CSK);
1287 void addDecl(EvalInfo &Info, const Expr *E,
1288 const Decl *D, bool Virtual = false) {
1289 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
1290 Designator.addDeclUnchecked(D, Virtual);
1292 void addUnsizedArray(EvalInfo &Info, QualType ElemTy) {
1293 assert(Designator.Entries.empty() && getType(Base)->isPointerType());
1294 assert(isBaseAnAllocSizeCall(Base) &&
1295 "Only alloc_size bases can have unsized arrays");
1296 Designator.FirstEntryIsAnUnsizedArray = true;
1297 Designator.addUnsizedArrayUnchecked(ElemTy);
1299 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1300 if (checkSubobject(Info, E, CSK_ArrayToPointer))
1301 Designator.addArrayUnchecked(CAT);
1303 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1304 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
1305 Designator.addComplexUnchecked(EltTy, Imag);
1307 void clearIsNullPointer() {
1310 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E,
1311 const APSInt &Index, CharUnits ElementSize) {
1312 // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB,
1313 // but we're not required to diagnose it and it's valid in C++.)
1317 // Compute the new offset in the appropriate width, wrapping at 64 bits.
1318 // FIXME: When compiling for a 32-bit target, we should use 32-bit
1320 uint64_t Offset64 = Offset.getQuantity();
1321 uint64_t ElemSize64 = ElementSize.getQuantity();
1322 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
1323 Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64);
1325 if (checkNullPointer(Info, E, CSK_ArrayIndex))
1326 Designator.adjustIndex(Info, E, Index);
1327 clearIsNullPointer();
1329 void adjustOffset(CharUnits N) {
1331 if (N.getQuantity())
1332 clearIsNullPointer();
1338 explicit MemberPtr(const ValueDecl *Decl) :
1339 DeclAndIsDerivedMember(Decl, false), Path() {}
1341 /// The member or (direct or indirect) field referred to by this member
1342 /// pointer, or 0 if this is a null member pointer.
1343 const ValueDecl *getDecl() const {
1344 return DeclAndIsDerivedMember.getPointer();
1346 /// Is this actually a member of some type derived from the relevant class?
1347 bool isDerivedMember() const {
1348 return DeclAndIsDerivedMember.getInt();
1350 /// Get the class which the declaration actually lives in.
1351 const CXXRecordDecl *getContainingRecord() const {
1352 return cast<CXXRecordDecl>(
1353 DeclAndIsDerivedMember.getPointer()->getDeclContext());
1356 void moveInto(APValue &V) const {
1357 V = APValue(getDecl(), isDerivedMember(), Path);
1359 void setFrom(const APValue &V) {
1360 assert(V.isMemberPointer());
1361 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1362 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1364 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
1365 Path.insert(Path.end(), P.begin(), P.end());
1368 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1369 /// whether the member is a member of some class derived from the class type
1370 /// of the member pointer.
1371 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1372 /// Path - The path of base/derived classes from the member declaration's
1373 /// class (exclusive) to the class type of the member pointer (inclusive).
1374 SmallVector<const CXXRecordDecl*, 4> Path;
1376 /// Perform a cast towards the class of the Decl (either up or down the
1378 bool castBack(const CXXRecordDecl *Class) {
1379 assert(!Path.empty());
1380 const CXXRecordDecl *Expected;
1381 if (Path.size() >= 2)
1382 Expected = Path[Path.size() - 2];
1384 Expected = getContainingRecord();
1385 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1386 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1387 // if B does not contain the original member and is not a base or
1388 // derived class of the class containing the original member, the result
1389 // of the cast is undefined.
1390 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1391 // (D::*). We consider that to be a language defect.
1397 /// Perform a base-to-derived member pointer cast.
1398 bool castToDerived(const CXXRecordDecl *Derived) {
1401 if (!isDerivedMember()) {
1402 Path.push_back(Derived);
1405 if (!castBack(Derived))
1408 DeclAndIsDerivedMember.setInt(false);
1411 /// Perform a derived-to-base member pointer cast.
1412 bool castToBase(const CXXRecordDecl *Base) {
1416 DeclAndIsDerivedMember.setInt(true);
1417 if (isDerivedMember()) {
1418 Path.push_back(Base);
1421 return castBack(Base);
1425 /// Compare two member pointers, which are assumed to be of the same type.
1426 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1427 if (!LHS.getDecl() || !RHS.getDecl())
1428 return !LHS.getDecl() && !RHS.getDecl();
1429 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1431 return LHS.Path == RHS.Path;
1435 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1436 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1437 const LValue &This, const Expr *E,
1438 bool AllowNonLiteralTypes = false);
1439 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
1440 bool InvalidBaseOK = false);
1441 static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
1442 bool InvalidBaseOK = false);
1443 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1445 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1446 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1447 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1449 static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1450 static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1451 static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
1453 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1455 //===----------------------------------------------------------------------===//
1457 //===----------------------------------------------------------------------===//
1459 /// Negate an APSInt in place, converting it to a signed form if necessary, and
1460 /// preserving its value (by extending by up to one bit as needed).
1461 static void negateAsSigned(APSInt &Int) {
1462 if (Int.isUnsigned() || Int.isMinSignedValue()) {
1463 Int = Int.extend(Int.getBitWidth() + 1);
1464 Int.setIsSigned(true);
1469 /// Produce a string describing the given constexpr call.
1470 static void describeCall(CallStackFrame *Frame, raw_ostream &Out) {
1471 unsigned ArgIndex = 0;
1472 bool IsMemberCall = isa<CXXMethodDecl>(Frame->Callee) &&
1473 !isa<CXXConstructorDecl>(Frame->Callee) &&
1474 cast<CXXMethodDecl>(Frame->Callee)->isInstance();
1477 Out << *Frame->Callee << '(';
1479 if (Frame->This && IsMemberCall) {
1481 Frame->This->moveInto(Val);
1482 Val.printPretty(Out, Frame->Info.Ctx,
1483 Frame->This->Designator.MostDerivedType);
1484 // FIXME: Add parens around Val if needed.
1485 Out << "->" << *Frame->Callee << '(';
1486 IsMemberCall = false;
1489 for (FunctionDecl::param_const_iterator I = Frame->Callee->param_begin(),
1490 E = Frame->Callee->param_end(); I != E; ++I, ++ArgIndex) {
1491 if (ArgIndex > (unsigned)IsMemberCall)
1494 const ParmVarDecl *Param = *I;
1495 const APValue &Arg = Frame->Arguments[ArgIndex];
1496 Arg.printPretty(Out, Frame->Info.Ctx, Param->getType());
1498 if (ArgIndex == 0 && IsMemberCall)
1499 Out << "->" << *Frame->Callee << '(';
1505 /// Evaluate an expression to see if it had side-effects, and discard its
1507 /// \return \c true if the caller should keep evaluating.
1508 static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
1510 if (!Evaluate(Scratch, Info, E))
1511 // We don't need the value, but we might have skipped a side effect here.
1512 return Info.noteSideEffect();
1516 /// Should this call expression be treated as a string literal?
1517 static bool IsStringLiteralCall(const CallExpr *E) {
1518 unsigned Builtin = E->getBuiltinCallee();
1519 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
1520 Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
1523 static bool IsGlobalLValue(APValue::LValueBase B) {
1524 // C++11 [expr.const]p3 An address constant expression is a prvalue core
1525 // constant expression of pointer type that evaluates to...
1527 // ... a null pointer value, or a prvalue core constant expression of type
1529 if (!B) return true;
1531 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
1532 // ... the address of an object with static storage duration,
1533 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
1534 return VD->hasGlobalStorage();
1535 // ... the address of a function,
1536 return isa<FunctionDecl>(D);
1539 const Expr *E = B.get<const Expr*>();
1540 switch (E->getStmtClass()) {
1543 case Expr::CompoundLiteralExprClass: {
1544 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
1545 return CLE->isFileScope() && CLE->isLValue();
1547 case Expr::MaterializeTemporaryExprClass:
1548 // A materialized temporary might have been lifetime-extended to static
1549 // storage duration.
1550 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
1551 // A string literal has static storage duration.
1552 case Expr::StringLiteralClass:
1553 case Expr::PredefinedExprClass:
1554 case Expr::ObjCStringLiteralClass:
1555 case Expr::ObjCEncodeExprClass:
1556 case Expr::CXXTypeidExprClass:
1557 case Expr::CXXUuidofExprClass:
1559 case Expr::CallExprClass:
1560 return IsStringLiteralCall(cast<CallExpr>(E));
1561 // For GCC compatibility, &&label has static storage duration.
1562 case Expr::AddrLabelExprClass:
1564 // A Block literal expression may be used as the initialization value for
1565 // Block variables at global or local static scope.
1566 case Expr::BlockExprClass:
1567 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
1568 case Expr::ImplicitValueInitExprClass:
1570 // We can never form an lvalue with an implicit value initialization as its
1571 // base through expression evaluation, so these only appear in one case: the
1572 // implicit variable declaration we invent when checking whether a constexpr
1573 // constructor can produce a constant expression. We must assume that such
1574 // an expression might be a global lvalue.
1579 static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
1580 assert(Base && "no location for a null lvalue");
1581 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1583 Info.Note(VD->getLocation(), diag::note_declared_at);
1585 Info.Note(Base.get<const Expr*>()->getExprLoc(),
1586 diag::note_constexpr_temporary_here);
1589 /// Check that this reference or pointer core constant expression is a valid
1590 /// value for an address or reference constant expression. Return true if we
1591 /// can fold this expression, whether or not it's a constant expression.
1592 static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
1593 QualType Type, const LValue &LVal) {
1594 bool IsReferenceType = Type->isReferenceType();
1596 APValue::LValueBase Base = LVal.getLValueBase();
1597 const SubobjectDesignator &Designator = LVal.getLValueDesignator();
1599 // Check that the object is a global. Note that the fake 'this' object we
1600 // manufacture when checking potential constant expressions is conservatively
1601 // assumed to be global here.
1602 if (!IsGlobalLValue(Base)) {
1603 if (Info.getLangOpts().CPlusPlus11) {
1604 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1605 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
1606 << IsReferenceType << !Designator.Entries.empty()
1608 NoteLValueLocation(Info, Base);
1612 // Don't allow references to temporaries to escape.
1615 assert((Info.checkingPotentialConstantExpression() ||
1616 LVal.getLValueCallIndex() == 0) &&
1617 "have call index for global lvalue");
1619 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
1620 if (const VarDecl *Var = dyn_cast<const VarDecl>(VD)) {
1621 // Check if this is a thread-local variable.
1622 if (Var->getTLSKind())
1625 // A dllimport variable never acts like a constant.
1626 if (Var->hasAttr<DLLImportAttr>())
1629 if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) {
1630 // __declspec(dllimport) must be handled very carefully:
1631 // We must never initialize an expression with the thunk in C++.
1632 // Doing otherwise would allow the same id-expression to yield
1633 // different addresses for the same function in different translation
1634 // units. However, this means that we must dynamically initialize the
1635 // expression with the contents of the import address table at runtime.
1637 // The C language has no notion of ODR; furthermore, it has no notion of
1638 // dynamic initialization. This means that we are permitted to
1639 // perform initialization with the address of the thunk.
1640 if (Info.getLangOpts().CPlusPlus && FD->hasAttr<DLLImportAttr>())
1645 // Allow address constant expressions to be past-the-end pointers. This is
1646 // an extension: the standard requires them to point to an object.
1647 if (!IsReferenceType)
1650 // A reference constant expression must refer to an object.
1652 // FIXME: diagnostic
1657 // Does this refer one past the end of some object?
1658 if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
1659 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1660 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
1661 << !Designator.Entries.empty() << !!VD << VD;
1662 NoteLValueLocation(Info, Base);
1668 /// Check that this core constant expression is of literal type, and if not,
1669 /// produce an appropriate diagnostic.
1670 static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
1671 const LValue *This = nullptr) {
1672 if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx))
1675 // C++1y: A constant initializer for an object o [...] may also invoke
1676 // constexpr constructors for o and its subobjects even if those objects
1677 // are of non-literal class types.
1679 // C++11 missed this detail for aggregates, so classes like this:
1680 // struct foo_t { union { int i; volatile int j; } u; };
1681 // are not (obviously) initializable like so:
1682 // __attribute__((__require_constant_initialization__))
1683 // static const foo_t x = {{0}};
1684 // because "i" is a subobject with non-literal initialization (due to the
1685 // volatile member of the union). See:
1686 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
1687 // Therefore, we use the C++1y behavior.
1688 if (This && Info.EvaluatingDecl == This->getLValueBase())
1691 // Prvalue constant expressions must be of literal types.
1692 if (Info.getLangOpts().CPlusPlus11)
1693 Info.FFDiag(E, diag::note_constexpr_nonliteral)
1696 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1700 /// Check that this core constant expression value is a valid value for a
1701 /// constant expression. If not, report an appropriate diagnostic. Does not
1702 /// check that the expression is of literal type.
1703 static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
1704 QualType Type, const APValue &Value) {
1705 if (Value.isUninit()) {
1706 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
1711 // We allow _Atomic(T) to be initialized from anything that T can be
1712 // initialized from.
1713 if (const AtomicType *AT = Type->getAs<AtomicType>())
1714 Type = AT->getValueType();
1716 // Core issue 1454: For a literal constant expression of array or class type,
1717 // each subobject of its value shall have been initialized by a constant
1719 if (Value.isArray()) {
1720 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
1721 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
1722 if (!CheckConstantExpression(Info, DiagLoc, EltTy,
1723 Value.getArrayInitializedElt(I)))
1726 if (!Value.hasArrayFiller())
1728 return CheckConstantExpression(Info, DiagLoc, EltTy,
1729 Value.getArrayFiller());
1731 if (Value.isUnion() && Value.getUnionField()) {
1732 return CheckConstantExpression(Info, DiagLoc,
1733 Value.getUnionField()->getType(),
1734 Value.getUnionValue());
1736 if (Value.isStruct()) {
1737 RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
1738 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
1739 unsigned BaseIndex = 0;
1740 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
1741 End = CD->bases_end(); I != End; ++I, ++BaseIndex) {
1742 if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
1743 Value.getStructBase(BaseIndex)))
1747 for (const auto *I : RD->fields()) {
1748 if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
1749 Value.getStructField(I->getFieldIndex())))
1754 if (Value.isLValue()) {
1756 LVal.setFrom(Info.Ctx, Value);
1757 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal);
1760 // Everything else is fine.
1764 static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
1765 return LVal.Base.dyn_cast<const ValueDecl*>();
1768 static bool IsLiteralLValue(const LValue &Value) {
1769 if (Value.CallIndex)
1771 const Expr *E = Value.Base.dyn_cast<const Expr*>();
1772 return E && !isa<MaterializeTemporaryExpr>(E);
1775 static bool IsWeakLValue(const LValue &Value) {
1776 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1777 return Decl && Decl->isWeak();
1780 static bool isZeroSized(const LValue &Value) {
1781 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1782 if (Decl && isa<VarDecl>(Decl)) {
1783 QualType Ty = Decl->getType();
1784 if (Ty->isArrayType())
1785 return Ty->isIncompleteType() ||
1786 Decl->getASTContext().getTypeSize(Ty) == 0;
1791 static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
1792 // A null base expression indicates a null pointer. These are always
1793 // evaluatable, and they are false unless the offset is zero.
1794 if (!Value.getLValueBase()) {
1795 Result = !Value.getLValueOffset().isZero();
1799 // We have a non-null base. These are generally known to be true, but if it's
1800 // a weak declaration it can be null at runtime.
1802 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
1803 return !Decl || !Decl->isWeak();
1806 static bool HandleConversionToBool(const APValue &Val, bool &Result) {
1807 switch (Val.getKind()) {
1808 case APValue::Uninitialized:
1811 Result = Val.getInt().getBoolValue();
1813 case APValue::Float:
1814 Result = !Val.getFloat().isZero();
1816 case APValue::ComplexInt:
1817 Result = Val.getComplexIntReal().getBoolValue() ||
1818 Val.getComplexIntImag().getBoolValue();
1820 case APValue::ComplexFloat:
1821 Result = !Val.getComplexFloatReal().isZero() ||
1822 !Val.getComplexFloatImag().isZero();
1824 case APValue::LValue:
1825 return EvalPointerValueAsBool(Val, Result);
1826 case APValue::MemberPointer:
1827 Result = Val.getMemberPointerDecl();
1829 case APValue::Vector:
1830 case APValue::Array:
1831 case APValue::Struct:
1832 case APValue::Union:
1833 case APValue::AddrLabelDiff:
1837 llvm_unreachable("unknown APValue kind");
1840 static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
1842 assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition");
1844 if (!Evaluate(Val, Info, E))
1846 return HandleConversionToBool(Val, Result);
1849 template<typename T>
1850 static bool HandleOverflow(EvalInfo &Info, const Expr *E,
1851 const T &SrcValue, QualType DestType) {
1852 Info.CCEDiag(E, diag::note_constexpr_overflow)
1853 << SrcValue << DestType;
1854 return Info.noteUndefinedBehavior();
1857 static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
1858 QualType SrcType, const APFloat &Value,
1859 QualType DestType, APSInt &Result) {
1860 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
1861 // Determine whether we are converting to unsigned or signed.
1862 bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
1864 Result = APSInt(DestWidth, !DestSigned);
1866 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
1867 & APFloat::opInvalidOp)
1868 return HandleOverflow(Info, E, Value, DestType);
1872 static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
1873 QualType SrcType, QualType DestType,
1875 APFloat Value = Result;
1877 if (Result.convert(Info.Ctx.getFloatTypeSemantics(DestType),
1878 APFloat::rmNearestTiesToEven, &ignored)
1879 & APFloat::opOverflow)
1880 return HandleOverflow(Info, E, Value, DestType);
1884 static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
1885 QualType DestType, QualType SrcType,
1886 const APSInt &Value) {
1887 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
1888 APSInt Result = Value;
1889 // Figure out if this is a truncate, extend or noop cast.
1890 // If the input is signed, do a sign extend, noop, or truncate.
1891 Result = Result.extOrTrunc(DestWidth);
1892 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
1896 static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
1897 QualType SrcType, const APSInt &Value,
1898 QualType DestType, APFloat &Result) {
1899 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
1900 if (Result.convertFromAPInt(Value, Value.isSigned(),
1901 APFloat::rmNearestTiesToEven)
1902 & APFloat::opOverflow)
1903 return HandleOverflow(Info, E, Value, DestType);
1907 static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
1908 APValue &Value, const FieldDecl *FD) {
1909 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield");
1911 if (!Value.isInt()) {
1912 // Trying to store a pointer-cast-to-integer into a bitfield.
1913 // FIXME: In this case, we should provide the diagnostic for casting
1914 // a pointer to an integer.
1915 assert(Value.isLValue() && "integral value neither int nor lvalue?");
1920 APSInt &Int = Value.getInt();
1921 unsigned OldBitWidth = Int.getBitWidth();
1922 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx);
1923 if (NewBitWidth < OldBitWidth)
1924 Int = Int.trunc(NewBitWidth).extend(OldBitWidth);
1928 static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
1931 if (!Evaluate(SVal, Info, E))
1934 Res = SVal.getInt();
1937 if (SVal.isFloat()) {
1938 Res = SVal.getFloat().bitcastToAPInt();
1941 if (SVal.isVector()) {
1942 QualType VecTy = E->getType();
1943 unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
1944 QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
1945 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
1946 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
1947 Res = llvm::APInt::getNullValue(VecSize);
1948 for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
1949 APValue &Elt = SVal.getVectorElt(i);
1950 llvm::APInt EltAsInt;
1952 EltAsInt = Elt.getInt();
1953 } else if (Elt.isFloat()) {
1954 EltAsInt = Elt.getFloat().bitcastToAPInt();
1956 // Don't try to handle vectors of anything other than int or float
1957 // (not sure if it's possible to hit this case).
1958 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1961 unsigned BaseEltSize = EltAsInt.getBitWidth();
1963 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
1965 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
1969 // Give up if the input isn't an int, float, or vector. For example, we
1970 // reject "(v4i16)(intptr_t)&a".
1971 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1975 /// Perform the given integer operation, which is known to need at most BitWidth
1976 /// bits, and check for overflow in the original type (if that type was not an
1978 template<typename Operation>
1979 static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
1980 const APSInt &LHS, const APSInt &RHS,
1981 unsigned BitWidth, Operation Op,
1983 if (LHS.isUnsigned()) {
1984 Result = Op(LHS, RHS);
1988 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
1989 Result = Value.trunc(LHS.getBitWidth());
1990 if (Result.extend(BitWidth) != Value) {
1991 if (Info.checkingForOverflow())
1992 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
1993 diag::warn_integer_constant_overflow)
1994 << Result.toString(10) << E->getType();
1996 return HandleOverflow(Info, E, Value, E->getType());
2001 /// Perform the given binary integer operation.
2002 static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS,
2003 BinaryOperatorKind Opcode, APSInt RHS,
2010 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
2011 std::multiplies<APSInt>(), Result);
2013 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2014 std::plus<APSInt>(), Result);
2016 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2017 std::minus<APSInt>(), Result);
2018 case BO_And: Result = LHS & RHS; return true;
2019 case BO_Xor: Result = LHS ^ RHS; return true;
2020 case BO_Or: Result = LHS | RHS; return true;
2024 Info.FFDiag(E, diag::note_expr_divide_by_zero);
2027 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
2028 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
2029 // this operation and gives the two's complement result.
2030 if (RHS.isNegative() && RHS.isAllOnesValue() &&
2031 LHS.isSigned() && LHS.isMinSignedValue())
2032 return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1),
2036 if (Info.getLangOpts().OpenCL)
2037 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2038 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2039 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2041 else if (RHS.isSigned() && RHS.isNegative()) {
2042 // During constant-folding, a negative shift is an opposite shift. Such
2043 // a shift is not a constant expression.
2044 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2049 // C++11 [expr.shift]p1: Shift width must be less than the bit width of
2050 // the shifted type.
2051 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2053 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2054 << RHS << E->getType() << LHS.getBitWidth();
2055 } else if (LHS.isSigned()) {
2056 // C++11 [expr.shift]p2: A signed left shift must have a non-negative
2057 // operand, and must not overflow the corresponding unsigned type.
2058 if (LHS.isNegative())
2059 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
2060 else if (LHS.countLeadingZeros() < SA)
2061 Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
2067 if (Info.getLangOpts().OpenCL)
2068 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2069 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2070 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2072 else if (RHS.isSigned() && RHS.isNegative()) {
2073 // During constant-folding, a negative shift is an opposite shift. Such a
2074 // shift is not a constant expression.
2075 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2080 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
2082 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2084 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2085 << RHS << E->getType() << LHS.getBitWidth();
2090 case BO_LT: Result = LHS < RHS; return true;
2091 case BO_GT: Result = LHS > RHS; return true;
2092 case BO_LE: Result = LHS <= RHS; return true;
2093 case BO_GE: Result = LHS >= RHS; return true;
2094 case BO_EQ: Result = LHS == RHS; return true;
2095 case BO_NE: Result = LHS != RHS; return true;
2099 /// Perform the given binary floating-point operation, in-place, on LHS.
2100 static bool handleFloatFloatBinOp(EvalInfo &Info, const Expr *E,
2101 APFloat &LHS, BinaryOperatorKind Opcode,
2102 const APFloat &RHS) {
2108 LHS.multiply(RHS, APFloat::rmNearestTiesToEven);
2111 LHS.add(RHS, APFloat::rmNearestTiesToEven);
2114 LHS.subtract(RHS, APFloat::rmNearestTiesToEven);
2117 LHS.divide(RHS, APFloat::rmNearestTiesToEven);
2121 if (LHS.isInfinity() || LHS.isNaN()) {
2122 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
2123 return Info.noteUndefinedBehavior();
2128 /// Cast an lvalue referring to a base subobject to a derived class, by
2129 /// truncating the lvalue's path to the given length.
2130 static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
2131 const RecordDecl *TruncatedType,
2132 unsigned TruncatedElements) {
2133 SubobjectDesignator &D = Result.Designator;
2135 // Check we actually point to a derived class object.
2136 if (TruncatedElements == D.Entries.size())
2138 assert(TruncatedElements >= D.MostDerivedPathLength &&
2139 "not casting to a derived class");
2140 if (!Result.checkSubobject(Info, E, CSK_Derived))
2143 // Truncate the path to the subobject, and remove any derived-to-base offsets.
2144 const RecordDecl *RD = TruncatedType;
2145 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
2146 if (RD->isInvalidDecl()) return false;
2147 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
2148 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
2149 if (isVirtualBaseClass(D.Entries[I]))
2150 Result.Offset -= Layout.getVBaseClassOffset(Base);
2152 Result.Offset -= Layout.getBaseClassOffset(Base);
2155 D.Entries.resize(TruncatedElements);
2159 static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2160 const CXXRecordDecl *Derived,
2161 const CXXRecordDecl *Base,
2162 const ASTRecordLayout *RL = nullptr) {
2164 if (Derived->isInvalidDecl()) return false;
2165 RL = &Info.Ctx.getASTRecordLayout(Derived);
2168 Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
2169 Obj.addDecl(Info, E, Base, /*Virtual*/ false);
2173 static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2174 const CXXRecordDecl *DerivedDecl,
2175 const CXXBaseSpecifier *Base) {
2176 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
2178 if (!Base->isVirtual())
2179 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
2181 SubobjectDesignator &D = Obj.Designator;
2185 // Extract most-derived object and corresponding type.
2186 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
2187 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
2190 // Find the virtual base class.
2191 if (DerivedDecl->isInvalidDecl()) return false;
2192 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
2193 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
2194 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
2198 static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
2199 QualType Type, LValue &Result) {
2200 for (CastExpr::path_const_iterator PathI = E->path_begin(),
2201 PathE = E->path_end();
2202 PathI != PathE; ++PathI) {
2203 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
2206 Type = (*PathI)->getType();
2211 /// Update LVal to refer to the given field, which must be a member of the type
2212 /// currently described by LVal.
2213 static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
2214 const FieldDecl *FD,
2215 const ASTRecordLayout *RL = nullptr) {
2217 if (FD->getParent()->isInvalidDecl()) return false;
2218 RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
2221 unsigned I = FD->getFieldIndex();
2222 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)));
2223 LVal.addDecl(Info, E, FD);
2227 /// Update LVal to refer to the given indirect field.
2228 static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
2230 const IndirectFieldDecl *IFD) {
2231 for (const auto *C : IFD->chain())
2232 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C)))
2237 /// Get the size of the given type in char units.
2238 static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
2239 QualType Type, CharUnits &Size) {
2240 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
2242 if (Type->isVoidType() || Type->isFunctionType()) {
2243 Size = CharUnits::One();
2247 if (Type->isDependentType()) {
2252 if (!Type->isConstantSizeType()) {
2253 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
2254 // FIXME: Better diagnostic.
2259 Size = Info.Ctx.getTypeSizeInChars(Type);
2263 /// Update a pointer value to model pointer arithmetic.
2264 /// \param Info - Information about the ongoing evaluation.
2265 /// \param E - The expression being evaluated, for diagnostic purposes.
2266 /// \param LVal - The pointer value to be updated.
2267 /// \param EltTy - The pointee type represented by LVal.
2268 /// \param Adjustment - The adjustment, in objects of type EltTy, to add.
2269 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
2270 LValue &LVal, QualType EltTy,
2271 APSInt Adjustment) {
2272 CharUnits SizeOfPointee;
2273 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
2276 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee);
2280 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
2281 LValue &LVal, QualType EltTy,
2282 int64_t Adjustment) {
2283 return HandleLValueArrayAdjustment(Info, E, LVal, EltTy,
2284 APSInt::get(Adjustment));
2287 /// Update an lvalue to refer to a component of a complex number.
2288 /// \param Info - Information about the ongoing evaluation.
2289 /// \param LVal - The lvalue to be updated.
2290 /// \param EltTy - The complex number's component type.
2291 /// \param Imag - False for the real component, true for the imaginary.
2292 static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
2293 LValue &LVal, QualType EltTy,
2296 CharUnits SizeOfComponent;
2297 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
2299 LVal.Offset += SizeOfComponent;
2301 LVal.addComplex(Info, E, EltTy, Imag);
2305 static bool handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv,
2306 QualType Type, const LValue &LVal,
2309 /// Try to evaluate the initializer for a variable declaration.
2311 /// \param Info Information about the ongoing evaluation.
2312 /// \param E An expression to be used when printing diagnostics.
2313 /// \param VD The variable whose initializer should be obtained.
2314 /// \param Frame The frame in which the variable was created. Must be null
2315 /// if this variable is not local to the evaluation.
2316 /// \param Result Filled in with a pointer to the value of the variable.
2317 static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
2318 const VarDecl *VD, CallStackFrame *Frame,
2321 // If this is a parameter to an active constexpr function call, perform
2322 // argument substitution.
2323 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) {
2324 // Assume arguments of a potential constant expression are unknown
2325 // constant expressions.
2326 if (Info.checkingPotentialConstantExpression())
2328 if (!Frame || !Frame->Arguments) {
2329 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2332 Result = &Frame->Arguments[PVD->getFunctionScopeIndex()];
2336 // If this is a local variable, dig out its value.
2338 Result = Frame->getTemporary(VD);
2340 // Assume variables referenced within a lambda's call operator that were
2341 // not declared within the call operator are captures and during checking
2342 // of a potential constant expression, assume they are unknown constant
2344 assert(isLambdaCallOperator(Frame->Callee) &&
2345 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&
2346 "missing value for local variable");
2347 if (Info.checkingPotentialConstantExpression())
2349 // FIXME: implement capture evaluation during constant expr evaluation.
2350 Info.FFDiag(E->getLocStart(),
2351 diag::note_unimplemented_constexpr_lambda_feature_ast)
2352 << "captures not currently allowed";
2358 // Dig out the initializer, and use the declaration which it's attached to.
2359 const Expr *Init = VD->getAnyInitializer(VD);
2360 if (!Init || Init->isValueDependent()) {
2361 // If we're checking a potential constant expression, the variable could be
2362 // initialized later.
2363 if (!Info.checkingPotentialConstantExpression())
2364 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2368 // If we're currently evaluating the initializer of this declaration, use that
2370 if (Info.EvaluatingDecl.dyn_cast<const ValueDecl*>() == VD) {
2371 Result = Info.EvaluatingDeclValue;
2375 // Never evaluate the initializer of a weak variable. We can't be sure that
2376 // this is the definition which will be used.
2378 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2382 // Check that we can fold the initializer. In C++, we will have already done
2383 // this in the cases where it matters for conformance.
2384 SmallVector<PartialDiagnosticAt, 8> Notes;
2385 if (!VD->evaluateValue(Notes)) {
2386 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant,
2387 Notes.size() + 1) << VD;
2388 Info.Note(VD->getLocation(), diag::note_declared_at);
2389 Info.addNotes(Notes);
2391 } else if (!VD->checkInitIsICE()) {
2392 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant,
2393 Notes.size() + 1) << VD;
2394 Info.Note(VD->getLocation(), diag::note_declared_at);
2395 Info.addNotes(Notes);
2398 Result = VD->getEvaluatedValue();
2402 static bool IsConstNonVolatile(QualType T) {
2403 Qualifiers Quals = T.getQualifiers();
2404 return Quals.hasConst() && !Quals.hasVolatile();
2407 /// Get the base index of the given base class within an APValue representing
2408 /// the given derived class.
2409 static unsigned getBaseIndex(const CXXRecordDecl *Derived,
2410 const CXXRecordDecl *Base) {
2411 Base = Base->getCanonicalDecl();
2413 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
2414 E = Derived->bases_end(); I != E; ++I, ++Index) {
2415 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
2419 llvm_unreachable("base class missing from derived class's bases list");
2422 /// Extract the value of a character from a string literal.
2423 static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
2425 // FIXME: Support MakeStringConstant
2426 if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) {
2428 Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str);
2429 assert(Index <= Str.size() && "Index too large");
2430 return APSInt::getUnsigned(Str.c_str()[Index]);
2433 if (auto PE = dyn_cast<PredefinedExpr>(Lit))
2434 Lit = PE->getFunctionName();
2435 const StringLiteral *S = cast<StringLiteral>(Lit);
2436 const ConstantArrayType *CAT =
2437 Info.Ctx.getAsConstantArrayType(S->getType());
2438 assert(CAT && "string literal isn't an array");
2439 QualType CharType = CAT->getElementType();
2440 assert(CharType->isIntegerType() && "unexpected character type");
2442 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
2443 CharType->isUnsignedIntegerType());
2444 if (Index < S->getLength())
2445 Value = S->getCodeUnit(Index);
2449 // Expand a string literal into an array of characters.
2450 static void expandStringLiteral(EvalInfo &Info, const Expr *Lit,
2452 const StringLiteral *S = cast<StringLiteral>(Lit);
2453 const ConstantArrayType *CAT =
2454 Info.Ctx.getAsConstantArrayType(S->getType());
2455 assert(CAT && "string literal isn't an array");
2456 QualType CharType = CAT->getElementType();
2457 assert(CharType->isIntegerType() && "unexpected character type");
2459 unsigned Elts = CAT->getSize().getZExtValue();
2460 Result = APValue(APValue::UninitArray(),
2461 std::min(S->getLength(), Elts), Elts);
2462 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
2463 CharType->isUnsignedIntegerType());
2464 if (Result.hasArrayFiller())
2465 Result.getArrayFiller() = APValue(Value);
2466 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
2467 Value = S->getCodeUnit(I);
2468 Result.getArrayInitializedElt(I) = APValue(Value);
2472 // Expand an array so that it has more than Index filled elements.
2473 static void expandArray(APValue &Array, unsigned Index) {
2474 unsigned Size = Array.getArraySize();
2475 assert(Index < Size);
2477 // Always at least double the number of elements for which we store a value.
2478 unsigned OldElts = Array.getArrayInitializedElts();
2479 unsigned NewElts = std::max(Index+1, OldElts * 2);
2480 NewElts = std::min(Size, std::max(NewElts, 8u));
2482 // Copy the data across.
2483 APValue NewValue(APValue::UninitArray(), NewElts, Size);
2484 for (unsigned I = 0; I != OldElts; ++I)
2485 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I));
2486 for (unsigned I = OldElts; I != NewElts; ++I)
2487 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
2488 if (NewValue.hasArrayFiller())
2489 NewValue.getArrayFiller() = Array.getArrayFiller();
2490 Array.swap(NewValue);
2493 /// Determine whether a type would actually be read by an lvalue-to-rvalue
2494 /// conversion. If it's of class type, we may assume that the copy operation
2495 /// is trivial. Note that this is never true for a union type with fields
2496 /// (because the copy always "reads" the active member) and always true for
2497 /// a non-class type.
2498 static bool isReadByLvalueToRvalueConversion(QualType T) {
2499 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
2500 if (!RD || (RD->isUnion() && !RD->field_empty()))
2505 for (auto *Field : RD->fields())
2506 if (isReadByLvalueToRvalueConversion(Field->getType()))
2509 for (auto &BaseSpec : RD->bases())
2510 if (isReadByLvalueToRvalueConversion(BaseSpec.getType()))
2516 /// Diagnose an attempt to read from any unreadable field within the specified
2517 /// type, which might be a class type.
2518 static bool diagnoseUnreadableFields(EvalInfo &Info, const Expr *E,
2520 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
2524 if (!RD->hasMutableFields())
2527 for (auto *Field : RD->fields()) {
2528 // If we're actually going to read this field in some way, then it can't
2529 // be mutable. If we're in a union, then assigning to a mutable field
2530 // (even an empty one) can change the active member, so that's not OK.
2531 // FIXME: Add core issue number for the union case.
2532 if (Field->isMutable() &&
2533 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
2534 Info.FFDiag(E, diag::note_constexpr_ltor_mutable, 1) << Field;
2535 Info.Note(Field->getLocation(), diag::note_declared_at);
2539 if (diagnoseUnreadableFields(Info, E, Field->getType()))
2543 for (auto &BaseSpec : RD->bases())
2544 if (diagnoseUnreadableFields(Info, E, BaseSpec.getType()))
2547 // All mutable fields were empty, and thus not actually read.
2551 /// Kinds of access we can perform on an object, for diagnostics.
2560 /// A handle to a complete object (an object that is not a subobject of
2561 /// another object).
2562 struct CompleteObject {
2563 /// The value of the complete object.
2565 /// The type of the complete object.
2568 CompleteObject() : Value(nullptr) {}
2569 CompleteObject(APValue *Value, QualType Type)
2570 : Value(Value), Type(Type) {
2571 assert(Value && "missing value for complete object");
2574 explicit operator bool() const { return Value; }
2576 } // end anonymous namespace
2578 /// Find the designated sub-object of an rvalue.
2579 template<typename SubobjectHandler>
2580 typename SubobjectHandler::result_type
2581 findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
2582 const SubobjectDesignator &Sub, SubobjectHandler &handler) {
2584 // A diagnostic will have already been produced.
2585 return handler.failed();
2586 if (Sub.isOnePastTheEnd()) {
2587 if (Info.getLangOpts().CPlusPlus11)
2588 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2589 << handler.AccessKind;
2592 return handler.failed();
2595 APValue *O = Obj.Value;
2596 QualType ObjType = Obj.Type;
2597 const FieldDecl *LastField = nullptr;
2599 // Walk the designator's path to find the subobject.
2600 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
2601 if (O->isUninit()) {
2602 if (!Info.checkingPotentialConstantExpression())
2603 Info.FFDiag(E, diag::note_constexpr_access_uninit) << handler.AccessKind;
2604 return handler.failed();
2608 // If we are reading an object of class type, there may still be more
2609 // things we need to check: if there are any mutable subobjects, we
2610 // cannot perform this read. (This only happens when performing a trivial
2611 // copy or assignment.)
2612 if (ObjType->isRecordType() && handler.AccessKind == AK_Read &&
2613 diagnoseUnreadableFields(Info, E, ObjType))
2614 return handler.failed();
2616 if (!handler.found(*O, ObjType))
2619 // If we modified a bit-field, truncate it to the right width.
2620 if (handler.AccessKind != AK_Read &&
2621 LastField && LastField->isBitField() &&
2622 !truncateBitfieldValue(Info, E, *O, LastField))
2628 LastField = nullptr;
2629 if (ObjType->isArrayType()) {
2630 // Next subobject is an array element.
2631 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
2632 assert(CAT && "vla in literal type?");
2633 uint64_t Index = Sub.Entries[I].ArrayIndex;
2634 if (CAT->getSize().ule(Index)) {
2635 // Note, it should not be possible to form a pointer with a valid
2636 // designator which points more than one past the end of the array.
2637 if (Info.getLangOpts().CPlusPlus11)
2638 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2639 << handler.AccessKind;
2642 return handler.failed();
2645 ObjType = CAT->getElementType();
2647 // An array object is represented as either an Array APValue or as an
2648 // LValue which refers to a string literal.
2649 if (O->isLValue()) {
2650 assert(I == N - 1 && "extracting subobject of character?");
2651 assert(!O->hasLValuePath() || O->getLValuePath().empty());
2652 if (handler.AccessKind != AK_Read)
2653 expandStringLiteral(Info, O->getLValueBase().get<const Expr *>(),
2656 return handler.foundString(*O, ObjType, Index);
2659 if (O->getArrayInitializedElts() > Index)
2660 O = &O->getArrayInitializedElt(Index);
2661 else if (handler.AccessKind != AK_Read) {
2662 expandArray(*O, Index);
2663 O = &O->getArrayInitializedElt(Index);
2665 O = &O->getArrayFiller();
2666 } else if (ObjType->isAnyComplexType()) {
2667 // Next subobject is a complex number.
2668 uint64_t Index = Sub.Entries[I].ArrayIndex;
2670 if (Info.getLangOpts().CPlusPlus11)
2671 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2672 << handler.AccessKind;
2675 return handler.failed();
2678 bool WasConstQualified = ObjType.isConstQualified();
2679 ObjType = ObjType->castAs<ComplexType>()->getElementType();
2680 if (WasConstQualified)
2683 assert(I == N - 1 && "extracting subobject of scalar?");
2684 if (O->isComplexInt()) {
2685 return handler.found(Index ? O->getComplexIntImag()
2686 : O->getComplexIntReal(), ObjType);
2688 assert(O->isComplexFloat());
2689 return handler.found(Index ? O->getComplexFloatImag()
2690 : O->getComplexFloatReal(), ObjType);
2692 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
2693 if (Field->isMutable() && handler.AccessKind == AK_Read) {
2694 Info.FFDiag(E, diag::note_constexpr_ltor_mutable, 1)
2696 Info.Note(Field->getLocation(), diag::note_declared_at);
2697 return handler.failed();
2700 // Next subobject is a class, struct or union field.
2701 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
2702 if (RD->isUnion()) {
2703 const FieldDecl *UnionField = O->getUnionField();
2705 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
2706 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
2707 << handler.AccessKind << Field << !UnionField << UnionField;
2708 return handler.failed();
2710 O = &O->getUnionValue();
2712 O = &O->getStructField(Field->getFieldIndex());
2714 bool WasConstQualified = ObjType.isConstQualified();
2715 ObjType = Field->getType();
2716 if (WasConstQualified && !Field->isMutable())
2719 if (ObjType.isVolatileQualified()) {
2720 if (Info.getLangOpts().CPlusPlus) {
2721 // FIXME: Include a description of the path to the volatile subobject.
2722 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
2723 << handler.AccessKind << 2 << Field;
2724 Info.Note(Field->getLocation(), diag::note_declared_at);
2726 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2728 return handler.failed();
2733 // Next subobject is a base class.
2734 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
2735 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
2736 O = &O->getStructBase(getBaseIndex(Derived, Base));
2738 bool WasConstQualified = ObjType.isConstQualified();
2739 ObjType = Info.Ctx.getRecordType(Base);
2740 if (WasConstQualified)
2747 struct ExtractSubobjectHandler {
2751 static const AccessKinds AccessKind = AK_Read;
2753 typedef bool result_type;
2754 bool failed() { return false; }
2755 bool found(APValue &Subobj, QualType SubobjType) {
2759 bool found(APSInt &Value, QualType SubobjType) {
2760 Result = APValue(Value);
2763 bool found(APFloat &Value, QualType SubobjType) {
2764 Result = APValue(Value);
2767 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
2768 Result = APValue(extractStringLiteralCharacter(
2769 Info, Subobj.getLValueBase().get<const Expr *>(), Character));
2773 } // end anonymous namespace
2775 const AccessKinds ExtractSubobjectHandler::AccessKind;
2777 /// Extract the designated sub-object of an rvalue.
2778 static bool extractSubobject(EvalInfo &Info, const Expr *E,
2779 const CompleteObject &Obj,
2780 const SubobjectDesignator &Sub,
2782 ExtractSubobjectHandler Handler = { Info, Result };
2783 return findSubobject(Info, E, Obj, Sub, Handler);
2787 struct ModifySubobjectHandler {
2792 typedef bool result_type;
2793 static const AccessKinds AccessKind = AK_Assign;
2795 bool checkConst(QualType QT) {
2796 // Assigning to a const object has undefined behavior.
2797 if (QT.isConstQualified()) {
2798 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
2804 bool failed() { return false; }
2805 bool found(APValue &Subobj, QualType SubobjType) {
2806 if (!checkConst(SubobjType))
2808 // We've been given ownership of NewVal, so just swap it in.
2809 Subobj.swap(NewVal);
2812 bool found(APSInt &Value, QualType SubobjType) {
2813 if (!checkConst(SubobjType))
2815 if (!NewVal.isInt()) {
2816 // Maybe trying to write a cast pointer value into a complex?
2820 Value = NewVal.getInt();
2823 bool found(APFloat &Value, QualType SubobjType) {
2824 if (!checkConst(SubobjType))
2826 Value = NewVal.getFloat();
2829 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
2830 llvm_unreachable("shouldn't encounter string elements with ExpandArrays");
2833 } // end anonymous namespace
2835 const AccessKinds ModifySubobjectHandler::AccessKind;
2837 /// Update the designated sub-object of an rvalue to the given value.
2838 static bool modifySubobject(EvalInfo &Info, const Expr *E,
2839 const CompleteObject &Obj,
2840 const SubobjectDesignator &Sub,
2842 ModifySubobjectHandler Handler = { Info, NewVal, E };
2843 return findSubobject(Info, E, Obj, Sub, Handler);
2846 /// Find the position where two subobject designators diverge, or equivalently
2847 /// the length of the common initial subsequence.
2848 static unsigned FindDesignatorMismatch(QualType ObjType,
2849 const SubobjectDesignator &A,
2850 const SubobjectDesignator &B,
2851 bool &WasArrayIndex) {
2852 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
2853 for (/**/; I != N; ++I) {
2854 if (!ObjType.isNull() &&
2855 (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
2856 // Next subobject is an array element.
2857 if (A.Entries[I].ArrayIndex != B.Entries[I].ArrayIndex) {
2858 WasArrayIndex = true;
2861 if (ObjType->isAnyComplexType())
2862 ObjType = ObjType->castAs<ComplexType>()->getElementType();
2864 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
2866 if (A.Entries[I].BaseOrMember != B.Entries[I].BaseOrMember) {
2867 WasArrayIndex = false;
2870 if (const FieldDecl *FD = getAsField(A.Entries[I]))
2871 // Next subobject is a field.
2872 ObjType = FD->getType();
2874 // Next subobject is a base class.
2875 ObjType = QualType();
2878 WasArrayIndex = false;
2882 /// Determine whether the given subobject designators refer to elements of the
2883 /// same array object.
2884 static bool AreElementsOfSameArray(QualType ObjType,
2885 const SubobjectDesignator &A,
2886 const SubobjectDesignator &B) {
2887 if (A.Entries.size() != B.Entries.size())
2890 bool IsArray = A.MostDerivedIsArrayElement;
2891 if (IsArray && A.MostDerivedPathLength != A.Entries.size())
2892 // A is a subobject of the array element.
2895 // If A (and B) designates an array element, the last entry will be the array
2896 // index. That doesn't have to match. Otherwise, we're in the 'implicit array
2897 // of length 1' case, and the entire path must match.
2899 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
2900 return CommonLength >= A.Entries.size() - IsArray;
2903 /// Find the complete object to which an LValue refers.
2904 static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
2905 AccessKinds AK, const LValue &LVal,
2906 QualType LValType) {
2908 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
2909 return CompleteObject();
2912 CallStackFrame *Frame = nullptr;
2913 if (LVal.CallIndex) {
2914 Frame = Info.getCallFrame(LVal.CallIndex);
2916 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
2917 << AK << LVal.Base.is<const ValueDecl*>();
2918 NoteLValueLocation(Info, LVal.Base);
2919 return CompleteObject();
2923 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
2924 // is not a constant expression (even if the object is non-volatile). We also
2925 // apply this rule to C++98, in order to conform to the expected 'volatile'
2927 if (LValType.isVolatileQualified()) {
2928 if (Info.getLangOpts().CPlusPlus)
2929 Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
2933 return CompleteObject();
2936 // Compute value storage location and type of base object.
2937 APValue *BaseVal = nullptr;
2938 QualType BaseType = getType(LVal.Base);
2940 if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl*>()) {
2941 // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
2942 // In C++11, constexpr, non-volatile variables initialized with constant
2943 // expressions are constant expressions too. Inside constexpr functions,
2944 // parameters are constant expressions even if they're non-const.
2945 // In C++1y, objects local to a constant expression (those with a Frame) are
2946 // both readable and writable inside constant expressions.
2947 // In C, such things can also be folded, although they are not ICEs.
2948 const VarDecl *VD = dyn_cast<VarDecl>(D);
2950 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
2953 if (!VD || VD->isInvalidDecl()) {
2955 return CompleteObject();
2958 // Accesses of volatile-qualified objects are not allowed.
2959 if (BaseType.isVolatileQualified()) {
2960 if (Info.getLangOpts().CPlusPlus) {
2961 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
2963 Info.Note(VD->getLocation(), diag::note_declared_at);
2967 return CompleteObject();
2970 // Unless we're looking at a local variable or argument in a constexpr call,
2971 // the variable we're reading must be const.
2973 if (Info.getLangOpts().CPlusPlus14 &&
2974 VD == Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()) {
2975 // OK, we can read and modify an object if we're in the process of
2976 // evaluating its initializer, because its lifetime began in this
2978 } else if (AK != AK_Read) {
2979 // All the remaining cases only permit reading.
2980 Info.FFDiag(E, diag::note_constexpr_modify_global);
2981 return CompleteObject();
2982 } else if (VD->isConstexpr()) {
2983 // OK, we can read this variable.
2984 } else if (BaseType->isIntegralOrEnumerationType()) {
2985 // In OpenCL if a variable is in constant address space it is a const value.
2986 if (!(BaseType.isConstQualified() ||
2987 (Info.getLangOpts().OpenCL &&
2988 BaseType.getAddressSpace() == LangAS::opencl_constant))) {
2989 if (Info.getLangOpts().CPlusPlus) {
2990 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
2991 Info.Note(VD->getLocation(), diag::note_declared_at);
2995 return CompleteObject();
2997 } else if (BaseType->isFloatingType() && BaseType.isConstQualified()) {
2998 // We support folding of const floating-point types, in order to make
2999 // static const data members of such types (supported as an extension)
3001 if (Info.getLangOpts().CPlusPlus11) {
3002 Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
3003 Info.Note(VD->getLocation(), diag::note_declared_at);
3007 } else if (BaseType.isConstQualified() && VD->hasDefinition(Info.Ctx)) {
3008 Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr) << VD;
3009 // Keep evaluating to see what we can do.
3011 // FIXME: Allow folding of values of any literal type in all languages.
3012 if (Info.checkingPotentialConstantExpression() &&
3013 VD->getType().isConstQualified() && !VD->hasDefinition(Info.Ctx)) {
3014 // The definition of this variable could be constexpr. We can't
3015 // access it right now, but may be able to in future.
3016 } else if (Info.getLangOpts().CPlusPlus11) {
3017 Info.FFDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
3018 Info.Note(VD->getLocation(), diag::note_declared_at);
3022 return CompleteObject();
3026 if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal))
3027 return CompleteObject();
3029 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
3032 if (const MaterializeTemporaryExpr *MTE =
3033 dyn_cast<MaterializeTemporaryExpr>(Base)) {
3034 assert(MTE->getStorageDuration() == SD_Static &&
3035 "should have a frame for a non-global materialized temporary");
3037 // Per C++1y [expr.const]p2:
3038 // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
3039 // - a [...] glvalue of integral or enumeration type that refers to
3040 // a non-volatile const object [...]
3042 // - a [...] glvalue of literal type that refers to a non-volatile
3043 // object whose lifetime began within the evaluation of e.
3045 // C++11 misses the 'began within the evaluation of e' check and
3046 // instead allows all temporaries, including things like:
3049 // constexpr int k = r;
3050 // Therefore we use the C++1y rules in C++11 too.
3051 const ValueDecl *VD = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>();
3052 const ValueDecl *ED = MTE->getExtendingDecl();
3053 if (!(BaseType.isConstQualified() &&
3054 BaseType->isIntegralOrEnumerationType()) &&
3055 !(VD && VD->getCanonicalDecl() == ED->getCanonicalDecl())) {
3056 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
3057 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
3058 return CompleteObject();
3061 BaseVal = Info.Ctx.getMaterializedTemporaryValue(MTE, false);
3062 assert(BaseVal && "got reference to unevaluated temporary");
3065 return CompleteObject();
3068 BaseVal = Frame->getTemporary(Base);
3069 assert(BaseVal && "missing value for temporary");
3072 // Volatile temporary objects cannot be accessed in constant expressions.
3073 if (BaseType.isVolatileQualified()) {
3074 if (Info.getLangOpts().CPlusPlus) {
3075 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
3077 Info.Note(Base->getExprLoc(), diag::note_constexpr_temporary_here);
3081 return CompleteObject();
3085 // During the construction of an object, it is not yet 'const'.
3086 // FIXME: We don't set up EvaluatingDecl for local variables or temporaries,
3087 // and this doesn't do quite the right thing for const subobjects of the
3088 // object under construction.
3089 if (LVal.getLValueBase() == Info.EvaluatingDecl) {
3090 BaseType = Info.Ctx.getCanonicalType(BaseType);
3091 BaseType.removeLocalConst();
3094 // In C++1y, we can't safely access any mutable state when we might be
3095 // evaluating after an unmodeled side effect.
3097 // FIXME: Not all local state is mutable. Allow local constant subobjects
3098 // to be read here (but take care with 'mutable' fields).
3099 if ((Frame && Info.getLangOpts().CPlusPlus14 &&
3100 Info.EvalStatus.HasSideEffects) ||
3101 (AK != AK_Read && Info.IsSpeculativelyEvaluating))
3102 return CompleteObject();
3104 return CompleteObject(BaseVal, BaseType);
3107 /// \brief Perform an lvalue-to-rvalue conversion on the given glvalue. This
3108 /// can also be used for 'lvalue-to-lvalue' conversions for looking up the
3109 /// glvalue referred to by an entity of reference type.
3111 /// \param Info - Information about the ongoing evaluation.
3112 /// \param Conv - The expression for which we are performing the conversion.
3113 /// Used for diagnostics.
3114 /// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
3115 /// case of a non-class type).
3116 /// \param LVal - The glvalue on which we are attempting to perform this action.
3117 /// \param RVal - The produced value will be placed here.
3118 static bool handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv,
3120 const LValue &LVal, APValue &RVal) {
3121 if (LVal.Designator.Invalid)
3124 // Check for special cases where there is no existing APValue to look at.
3125 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
3126 if (Base && !LVal.CallIndex && !Type.isVolatileQualified()) {
3127 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) {
3128 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
3129 // initializer until now for such expressions. Such an expression can't be
3130 // an ICE in C, so this only matters for fold.
3131 if (Type.isVolatileQualified()) {
3136 if (!Evaluate(Lit, Info, CLE->getInitializer()))
3138 CompleteObject LitObj(&Lit, Base->getType());
3139 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal);
3140 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) {
3141 // We represent a string literal array as an lvalue pointing at the
3142 // corresponding expression, rather than building an array of chars.
3143 // FIXME: Support ObjCEncodeExpr, MakeStringConstant
3144 APValue Str(Base, CharUnits::Zero(), APValue::NoLValuePath(), 0);
3145 CompleteObject StrObj(&Str, Base->getType());
3146 return extractSubobject(Info, Conv, StrObj, LVal.Designator, RVal);
3150 CompleteObject Obj = findCompleteObject(Info, Conv, AK_Read, LVal, Type);
3151 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal);
3154 /// Perform an assignment of Val to LVal. Takes ownership of Val.
3155 static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
3156 QualType LValType, APValue &Val) {
3157 if (LVal.Designator.Invalid)
3160 if (!Info.getLangOpts().CPlusPlus14) {
3165 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
3166 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
3169 static bool isOverflowingIntegerType(ASTContext &Ctx, QualType T) {
3170 return T->isSignedIntegerType() &&
3171 Ctx.getIntWidth(T) >= Ctx.getIntWidth(Ctx.IntTy);
3175 struct CompoundAssignSubobjectHandler {
3178 QualType PromotedLHSType;
3179 BinaryOperatorKind Opcode;
3182 static const AccessKinds AccessKind = AK_Assign;
3184 typedef bool result_type;
3186 bool checkConst(QualType QT) {
3187 // Assigning to a const object has undefined behavior.
3188 if (QT.isConstQualified()) {
3189 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3195 bool failed() { return false; }
3196 bool found(APValue &Subobj, QualType SubobjType) {
3197 switch (Subobj.getKind()) {
3199 return found(Subobj.getInt(), SubobjType);
3200 case APValue::Float:
3201 return found(Subobj.getFloat(), SubobjType);
3202 case APValue::ComplexInt:
3203 case APValue::ComplexFloat:
3204 // FIXME: Implement complex compound assignment.
3207 case APValue::LValue:
3208 return foundPointer(Subobj, SubobjType);
3210 // FIXME: can this happen?
3215 bool found(APSInt &Value, QualType SubobjType) {
3216 if (!checkConst(SubobjType))
3219 if (!SubobjType->isIntegerType() || !RHS.isInt()) {
3220 // We don't support compound assignment on integer-cast-to-pointer
3226 APSInt LHS = HandleIntToIntCast(Info, E, PromotedLHSType,
3228 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
3230 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
3233 bool found(APFloat &Value, QualType SubobjType) {
3234 return checkConst(SubobjType) &&
3235 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
3237 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
3238 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
3240 bool foundPointer(APValue &Subobj, QualType SubobjType) {
3241 if (!checkConst(SubobjType))
3244 QualType PointeeType;
3245 if (const PointerType *PT = SubobjType->getAs<PointerType>())
3246 PointeeType = PT->getPointeeType();
3248 if (PointeeType.isNull() || !RHS.isInt() ||
3249 (Opcode != BO_Add && Opcode != BO_Sub)) {
3254 APSInt Offset = RHS.getInt();
3255 if (Opcode == BO_Sub)
3256 negateAsSigned(Offset);
3259 LVal.setFrom(Info.Ctx, Subobj);
3260 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
3262 LVal.moveInto(Subobj);
3265 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
3266 llvm_unreachable("shouldn't encounter string elements here");
3269 } // end anonymous namespace
3271 const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
3273 /// Perform a compound assignment of LVal <op>= RVal.
3274 static bool handleCompoundAssignment(
3275 EvalInfo &Info, const Expr *E,
3276 const LValue &LVal, QualType LValType, QualType PromotedLValType,
3277 BinaryOperatorKind Opcode, const APValue &RVal) {
3278 if (LVal.Designator.Invalid)
3281 if (!Info.getLangOpts().CPlusPlus14) {
3286 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
3287 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
3289 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
3293 struct IncDecSubobjectHandler {
3296 AccessKinds AccessKind;
3299 typedef bool result_type;
3301 bool checkConst(QualType QT) {
3302 // Assigning to a const object has undefined behavior.
3303 if (QT.isConstQualified()) {
3304 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3310 bool failed() { return false; }
3311 bool found(APValue &Subobj, QualType SubobjType) {
3312 // Stash the old value. Also clear Old, so we don't clobber it later
3313 // if we're post-incrementing a complex.
3319 switch (Subobj.getKind()) {
3321 return found(Subobj.getInt(), SubobjType);
3322 case APValue::Float:
3323 return found(Subobj.getFloat(), SubobjType);
3324 case APValue::ComplexInt:
3325 return found(Subobj.getComplexIntReal(),
3326 SubobjType->castAs<ComplexType>()->getElementType()
3327 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
3328 case APValue::ComplexFloat:
3329 return found(Subobj.getComplexFloatReal(),
3330 SubobjType->castAs<ComplexType>()->getElementType()
3331 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
3332 case APValue::LValue:
3333 return foundPointer(Subobj, SubobjType);
3335 // FIXME: can this happen?
3340 bool found(APSInt &Value, QualType SubobjType) {
3341 if (!checkConst(SubobjType))
3344 if (!SubobjType->isIntegerType()) {
3345 // We don't support increment / decrement on integer-cast-to-pointer
3351 if (Old) *Old = APValue(Value);
3353 // bool arithmetic promotes to int, and the conversion back to bool
3354 // doesn't reduce mod 2^n, so special-case it.
3355 if (SubobjType->isBooleanType()) {
3356 if (AccessKind == AK_Increment)
3363 bool WasNegative = Value.isNegative();
3364 if (AccessKind == AK_Increment) {
3367 if (!WasNegative && Value.isNegative() &&
3368 isOverflowingIntegerType(Info.Ctx, SubobjType)) {
3369 APSInt ActualValue(Value, /*IsUnsigned*/true);
3370 return HandleOverflow(Info, E, ActualValue, SubobjType);
3375 if (WasNegative && !Value.isNegative() &&
3376 isOverflowingIntegerType(Info.Ctx, SubobjType)) {
3377 unsigned BitWidth = Value.getBitWidth();
3378 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
3379 ActualValue.setBit(BitWidth);
3380 return HandleOverflow(Info, E, ActualValue, SubobjType);
3385 bool found(APFloat &Value, QualType SubobjType) {
3386 if (!checkConst(SubobjType))
3389 if (Old) *Old = APValue(Value);
3391 APFloat One(Value.getSemantics(), 1);
3392 if (AccessKind == AK_Increment)
3393 Value.add(One, APFloat::rmNearestTiesToEven);
3395 Value.subtract(One, APFloat::rmNearestTiesToEven);
3398 bool foundPointer(APValue &Subobj, QualType SubobjType) {
3399 if (!checkConst(SubobjType))
3402 QualType PointeeType;
3403 if (const PointerType *PT = SubobjType->getAs<PointerType>())
3404 PointeeType = PT->getPointeeType();
3411 LVal.setFrom(Info.Ctx, Subobj);
3412 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
3413 AccessKind == AK_Increment ? 1 : -1))
3415 LVal.moveInto(Subobj);
3418 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
3419 llvm_unreachable("shouldn't encounter string elements here");
3422 } // end anonymous namespace
3424 /// Perform an increment or decrement on LVal.
3425 static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
3426 QualType LValType, bool IsIncrement, APValue *Old) {
3427 if (LVal.Designator.Invalid)
3430 if (!Info.getLangOpts().CPlusPlus14) {
3435 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
3436 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
3437 IncDecSubobjectHandler Handler = { Info, E, AK, Old };
3438 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
3441 /// Build an lvalue for the object argument of a member function call.
3442 static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
3444 if (Object->getType()->isPointerType())
3445 return EvaluatePointer(Object, This, Info);
3447 if (Object->isGLValue())
3448 return EvaluateLValue(Object, This, Info);
3450 if (Object->getType()->isLiteralType(Info.Ctx))
3451 return EvaluateTemporary(Object, This, Info);
3453 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
3457 /// HandleMemberPointerAccess - Evaluate a member access operation and build an
3458 /// lvalue referring to the result.
3460 /// \param Info - Information about the ongoing evaluation.
3461 /// \param LV - An lvalue referring to the base of the member pointer.
3462 /// \param RHS - The member pointer expression.
3463 /// \param IncludeMember - Specifies whether the member itself is included in
3464 /// the resulting LValue subobject designator. This is not possible when
3465 /// creating a bound member function.
3466 /// \return The field or method declaration to which the member pointer refers,
3467 /// or 0 if evaluation fails.
3468 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
3472 bool IncludeMember = true) {
3474 if (!EvaluateMemberPointer(RHS, MemPtr, Info))
3477 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
3478 // member value, the behavior is undefined.
3479 if (!MemPtr.getDecl()) {
3480 // FIXME: Specific diagnostic.
3485 if (MemPtr.isDerivedMember()) {
3486 // This is a member of some derived class. Truncate LV appropriately.
3487 // The end of the derived-to-base path for the base object must match the
3488 // derived-to-base path for the member pointer.
3489 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
3490 LV.Designator.Entries.size()) {
3494 unsigned PathLengthToMember =
3495 LV.Designator.Entries.size() - MemPtr.Path.size();
3496 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
3497 const CXXRecordDecl *LVDecl = getAsBaseClass(
3498 LV.Designator.Entries[PathLengthToMember + I]);
3499 const CXXRecordDecl *MPDecl = MemPtr.Path[I];
3500 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
3506 // Truncate the lvalue to the appropriate derived class.
3507 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
3508 PathLengthToMember))
3510 } else if (!MemPtr.Path.empty()) {
3511 // Extend the LValue path with the member pointer's path.
3512 LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
3513 MemPtr.Path.size() + IncludeMember);
3515 // Walk down to the appropriate base class.
3516 if (const PointerType *PT = LVType->getAs<PointerType>())
3517 LVType = PT->getPointeeType();
3518 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
3519 assert(RD && "member pointer access on non-class-type expression");
3520 // The first class in the path is that of the lvalue.
3521 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
3522 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
3523 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base))
3527 // Finally cast to the class containing the member.
3528 if (!HandleLValueDirectBase(Info, RHS, LV, RD,
3529 MemPtr.getContainingRecord()))
3533 // Add the member. Note that we cannot build bound member functions here.
3534 if (IncludeMember) {
3535 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) {
3536 if (!HandleLValueMember(Info, RHS, LV, FD))
3538 } else if (const IndirectFieldDecl *IFD =
3539 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) {
3540 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD))
3543 llvm_unreachable("can't construct reference to bound member function");
3547 return MemPtr.getDecl();
3550 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
3551 const BinaryOperator *BO,
3553 bool IncludeMember = true) {
3554 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI);
3556 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) {
3557 if (Info.noteFailure()) {
3559 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info);
3564 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV,
3565 BO->getRHS(), IncludeMember);
3568 /// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
3569 /// the provided lvalue, which currently refers to the base object.
3570 static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
3572 SubobjectDesignator &D = Result.Designator;
3573 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
3576 QualType TargetQT = E->getType();
3577 if (const PointerType *PT = TargetQT->getAs<PointerType>())
3578 TargetQT = PT->getPointeeType();
3580 // Check this cast lands within the final derived-to-base subobject path.
3581 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
3582 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
3583 << D.MostDerivedType << TargetQT;
3587 // Check the type of the final cast. We don't need to check the path,
3588 // since a cast can only be formed if the path is unique.
3589 unsigned NewEntriesSize = D.Entries.size() - E->path_size();
3590 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
3591 const CXXRecordDecl *FinalType;
3592 if (NewEntriesSize == D.MostDerivedPathLength)
3593 FinalType = D.MostDerivedType->getAsCXXRecordDecl();
3595 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
3596 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
3597 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
3598 << D.MostDerivedType << TargetQT;
3602 // Truncate the lvalue to the appropriate derived class.
3603 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
3607 enum EvalStmtResult {
3608 /// Evaluation failed.
3610 /// Hit a 'return' statement.
3612 /// Evaluation succeeded.
3614 /// Hit a 'continue' statement.
3616 /// Hit a 'break' statement.
3618 /// Still scanning for 'case' or 'default' statement.
3623 static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
3624 // We don't need to evaluate the initializer for a static local.
3625 if (!VD->hasLocalStorage())
3629 Result.set(VD, Info.CurrentCall->Index);
3630 APValue &Val = Info.CurrentCall->createTemporary(VD, true);
3632 const Expr *InitE = VD->getInit();
3634 Info.FFDiag(VD->getLocStart(), diag::note_constexpr_uninitialized)
3635 << false << VD->getType();
3640 if (InitE->isValueDependent())
3643 if (!EvaluateInPlace(Val, Info, Result, InitE)) {
3644 // Wipe out any partially-computed value, to allow tracking that this
3645 // evaluation failed.
3653 static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
3656 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
3657 OK &= EvaluateVarDecl(Info, VD);
3659 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D))
3660 for (auto *BD : DD->bindings())
3661 if (auto *VD = BD->getHoldingVar())
3662 OK &= EvaluateDecl(Info, VD);
3668 /// Evaluate a condition (either a variable declaration or an expression).
3669 static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
3670 const Expr *Cond, bool &Result) {
3671 FullExpressionRAII Scope(Info);
3672 if (CondDecl && !EvaluateDecl(Info, CondDecl))
3674 return EvaluateAsBooleanCondition(Cond, Result, Info);
3678 /// \brief A location where the result (returned value) of evaluating a
3679 /// statement should be stored.
3681 /// The APValue that should be filled in with the returned value.
3683 /// The location containing the result, if any (used to support RVO).
3688 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
3690 const SwitchCase *SC = nullptr);
3692 /// Evaluate the body of a loop, and translate the result as appropriate.
3693 static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
3695 const SwitchCase *Case = nullptr) {
3696 BlockScopeRAII Scope(Info);
3697 switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case)) {
3699 return ESR_Succeeded;
3702 return ESR_Continue;
3705 case ESR_CaseNotFound:
3708 llvm_unreachable("Invalid EvalStmtResult!");
3711 /// Evaluate a switch statement.
3712 static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
3713 const SwitchStmt *SS) {
3714 BlockScopeRAII Scope(Info);
3716 // Evaluate the switch condition.
3719 FullExpressionRAII Scope(Info);
3720 if (const Stmt *Init = SS->getInit()) {
3721 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
3722 if (ESR != ESR_Succeeded)
3725 if (SS->getConditionVariable() &&
3726 !EvaluateDecl(Info, SS->getConditionVariable()))
3728 if (!EvaluateInteger(SS->getCond(), Value, Info))
3732 // Find the switch case corresponding to the value of the condition.
3733 // FIXME: Cache this lookup.
3734 const SwitchCase *Found = nullptr;
3735 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
3736 SC = SC->getNextSwitchCase()) {
3737 if (isa<DefaultStmt>(SC)) {
3742 const CaseStmt *CS = cast<CaseStmt>(SC);
3743 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx);
3744 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx)
3746 if (LHS <= Value && Value <= RHS) {
3753 return ESR_Succeeded;
3755 // Search the switch body for the switch case and evaluate it from there.
3756 switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found)) {
3758 return ESR_Succeeded;
3764 case ESR_CaseNotFound:
3765 // This can only happen if the switch case is nested within a statement
3766 // expression. We have no intention of supporting that.
3767 Info.FFDiag(Found->getLocStart(), diag::note_constexpr_stmt_expr_unsupported);
3770 llvm_unreachable("Invalid EvalStmtResult!");
3773 // Evaluate a statement.
3774 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
3775 const Stmt *S, const SwitchCase *Case) {
3776 if (!Info.nextStep(S))
3779 // If we're hunting down a 'case' or 'default' label, recurse through
3780 // substatements until we hit the label.
3782 // FIXME: We don't start the lifetime of objects whose initialization we
3783 // jump over. However, such objects must be of class type with a trivial
3784 // default constructor that initialize all subobjects, so must be empty,
3785 // so this almost never matters.
3786 switch (S->getStmtClass()) {
3787 case Stmt::CompoundStmtClass:
3788 // FIXME: Precompute which substatement of a compound statement we
3789 // would jump to, and go straight there rather than performing a
3790 // linear scan each time.
3791 case Stmt::LabelStmtClass:
3792 case Stmt::AttributedStmtClass:
3793 case Stmt::DoStmtClass:
3796 case Stmt::CaseStmtClass:
3797 case Stmt::DefaultStmtClass:
3802 case Stmt::IfStmtClass: {
3803 // FIXME: Precompute which side of an 'if' we would jump to, and go
3804 // straight there rather than scanning both sides.
3805 const IfStmt *IS = cast<IfStmt>(S);
3807 // Wrap the evaluation in a block scope, in case it's a DeclStmt
3808 // preceded by our switch label.
3809 BlockScopeRAII Scope(Info);
3811 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case);
3812 if (ESR != ESR_CaseNotFound || !IS->getElse())
3814 return EvaluateStmt(Result, Info, IS->getElse(), Case);
3817 case Stmt::WhileStmtClass: {
3818 EvalStmtResult ESR =
3819 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case);
3820 if (ESR != ESR_Continue)
3825 case Stmt::ForStmtClass: {
3826 const ForStmt *FS = cast<ForStmt>(S);
3827 EvalStmtResult ESR =
3828 EvaluateLoopBody(Result, Info, FS->getBody(), Case);
3829 if (ESR != ESR_Continue)
3832 FullExpressionRAII IncScope(Info);
3833 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3839 case Stmt::DeclStmtClass:
3840 // FIXME: If the variable has initialization that can't be jumped over,
3841 // bail out of any immediately-surrounding compound-statement too.
3843 return ESR_CaseNotFound;
3847 switch (S->getStmtClass()) {
3849 if (const Expr *E = dyn_cast<Expr>(S)) {
3850 // Don't bother evaluating beyond an expression-statement which couldn't
3852 FullExpressionRAII Scope(Info);
3853 if (!EvaluateIgnoredValue(Info, E))
3855 return ESR_Succeeded;
3858 Info.FFDiag(S->getLocStart());
3861 case Stmt::NullStmtClass:
3862 return ESR_Succeeded;
3864 case Stmt::DeclStmtClass: {
3865 const DeclStmt *DS = cast<DeclStmt>(S);
3866 for (const auto *DclIt : DS->decls()) {
3867 // Each declaration initialization is its own full-expression.
3868 // FIXME: This isn't quite right; if we're performing aggregate
3869 // initialization, each braced subexpression is its own full-expression.
3870 FullExpressionRAII Scope(Info);
3871 if (!EvaluateDecl(Info, DclIt) && !Info.noteFailure())
3874 return ESR_Succeeded;
3877 case Stmt::ReturnStmtClass: {
3878 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
3879 FullExpressionRAII Scope(Info);
3882 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr)
3883 : Evaluate(Result.Value, Info, RetExpr)))
3885 return ESR_Returned;
3888 case Stmt::CompoundStmtClass: {
3889 BlockScopeRAII Scope(Info);
3891 const CompoundStmt *CS = cast<CompoundStmt>(S);
3892 for (const auto *BI : CS->body()) {
3893 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case);
3894 if (ESR == ESR_Succeeded)
3896 else if (ESR != ESR_CaseNotFound)
3899 return Case ? ESR_CaseNotFound : ESR_Succeeded;
3902 case Stmt::IfStmtClass: {
3903 const IfStmt *IS = cast<IfStmt>(S);
3905 // Evaluate the condition, as either a var decl or as an expression.
3906 BlockScopeRAII Scope(Info);
3907 if (const Stmt *Init = IS->getInit()) {
3908 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
3909 if (ESR != ESR_Succeeded)
3913 if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
3916 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
3917 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
3918 if (ESR != ESR_Succeeded)
3921 return ESR_Succeeded;
3924 case Stmt::WhileStmtClass: {
3925 const WhileStmt *WS = cast<WhileStmt>(S);
3927 BlockScopeRAII Scope(Info);
3929 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
3935 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
3936 if (ESR != ESR_Continue)
3939 return ESR_Succeeded;
3942 case Stmt::DoStmtClass: {
3943 const DoStmt *DS = cast<DoStmt>(S);
3946 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case);
3947 if (ESR != ESR_Continue)
3951 FullExpressionRAII CondScope(Info);
3952 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info))
3955 return ESR_Succeeded;
3958 case Stmt::ForStmtClass: {
3959 const ForStmt *FS = cast<ForStmt>(S);
3960 BlockScopeRAII Scope(Info);
3961 if (FS->getInit()) {
3962 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
3963 if (ESR != ESR_Succeeded)
3967 BlockScopeRAII Scope(Info);
3968 bool Continue = true;
3969 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
3970 FS->getCond(), Continue))
3975 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
3976 if (ESR != ESR_Continue)
3980 FullExpressionRAII IncScope(Info);
3981 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3985 return ESR_Succeeded;
3988 case Stmt::CXXForRangeStmtClass: {
3989 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S);
3990 BlockScopeRAII Scope(Info);
3992 // Initialize the __range variable.
3993 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt());
3994 if (ESR != ESR_Succeeded)
3997 // Create the __begin and __end iterators.
3998 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt());
3999 if (ESR != ESR_Succeeded)
4001 ESR = EvaluateStmt(Result, Info, FS->getEndStmt());
4002 if (ESR != ESR_Succeeded)
4006 // Condition: __begin != __end.
4008 bool Continue = true;
4009 FullExpressionRAII CondExpr(Info);
4010 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info))
4016 // User's variable declaration, initialized by *__begin.
4017 BlockScopeRAII InnerScope(Info);
4018 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt());
4019 if (ESR != ESR_Succeeded)
4023 ESR = EvaluateLoopBody(Result, Info, FS->getBody());
4024 if (ESR != ESR_Continue)
4027 // Increment: ++__begin
4028 if (!EvaluateIgnoredValue(Info, FS->getInc()))
4032 return ESR_Succeeded;
4035 case Stmt::SwitchStmtClass:
4036 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S));
4038 case Stmt::ContinueStmtClass:
4039 return ESR_Continue;
4041 case Stmt::BreakStmtClass:
4044 case Stmt::LabelStmtClass:
4045 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case);
4047 case Stmt::AttributedStmtClass:
4048 // As a general principle, C++11 attributes can be ignored without
4049 // any semantic impact.
4050 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(),
4053 case Stmt::CaseStmtClass:
4054 case Stmt::DefaultStmtClass:
4055 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case);
4059 /// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
4060 /// default constructor. If so, we'll fold it whether or not it's marked as
4061 /// constexpr. If it is marked as constexpr, we will never implicitly define it,
4062 /// so we need special handling.
4063 static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
4064 const CXXConstructorDecl *CD,
4065 bool IsValueInitialization) {
4066 if (!CD->isTrivial() || !CD->isDefaultConstructor())
4069 // Value-initialization does not call a trivial default constructor, so such a
4070 // call is a core constant expression whether or not the constructor is
4072 if (!CD->isConstexpr() && !IsValueInitialization) {
4073 if (Info.getLangOpts().CPlusPlus11) {
4074 // FIXME: If DiagDecl is an implicitly-declared special member function,
4075 // we should be much more explicit about why it's not constexpr.
4076 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
4077 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
4078 Info.Note(CD->getLocation(), diag::note_declared_at);
4080 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
4086 /// CheckConstexprFunction - Check that a function can be called in a constant
4088 static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
4089 const FunctionDecl *Declaration,
4090 const FunctionDecl *Definition,
4092 // Potential constant expressions can contain calls to declared, but not yet
4093 // defined, constexpr functions.
4094 if (Info.checkingPotentialConstantExpression() && !Definition &&
4095 Declaration->isConstexpr())
4098 // Bail out with no diagnostic if the function declaration itself is invalid.
4099 // We will have produced a relevant diagnostic while parsing it.
4100 if (Declaration->isInvalidDecl())
4103 // Can we evaluate this function call?
4104 if (Definition && Definition->isConstexpr() &&
4105 !Definition->isInvalidDecl() && Body)
4108 if (Info.getLangOpts().CPlusPlus11) {
4109 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
4111 // If this function is not constexpr because it is an inherited
4112 // non-constexpr constructor, diagnose that directly.
4113 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
4114 if (CD && CD->isInheritingConstructor()) {
4115 auto *Inherited = CD->getInheritedConstructor().getConstructor();
4116 if (!Inherited->isConstexpr())
4117 DiagDecl = CD = Inherited;
4120 // FIXME: If DiagDecl is an implicitly-declared special member function
4121 // or an inheriting constructor, we should be much more explicit about why
4122 // it's not constexpr.
4123 if (CD && CD->isInheritingConstructor())
4124 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
4125 << CD->getInheritedConstructor().getConstructor()->getParent();
4127 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
4128 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
4129 Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
4131 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
4136 /// Determine if a class has any fields that might need to be copied by a
4137 /// trivial copy or move operation.
4138 static bool hasFields(const CXXRecordDecl *RD) {
4139 if (!RD || RD->isEmpty())
4141 for (auto *FD : RD->fields()) {
4142 if (FD->isUnnamedBitfield())
4146 for (auto &Base : RD->bases())
4147 if (hasFields(Base.getType()->getAsCXXRecordDecl()))
4153 typedef SmallVector<APValue, 8> ArgVector;
4156 /// EvaluateArgs - Evaluate the arguments to a function call.
4157 static bool EvaluateArgs(ArrayRef<const Expr*> Args, ArgVector &ArgValues,
4159 bool Success = true;
4160 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
4162 if (!Evaluate(ArgValues[I - Args.begin()], Info, *I)) {
4163 // If we're checking for a potential constant expression, evaluate all
4164 // initializers even if some of them fail.
4165 if (!Info.noteFailure())
4173 /// Evaluate a function call.
4174 static bool HandleFunctionCall(SourceLocation CallLoc,
4175 const FunctionDecl *Callee, const LValue *This,
4176 ArrayRef<const Expr*> Args, const Stmt *Body,
4177 EvalInfo &Info, APValue &Result,
4178 const LValue *ResultSlot) {
4179 ArgVector ArgValues(Args.size());
4180 if (!EvaluateArgs(Args, ArgValues, Info))
4183 if (!Info.CheckCallLimit(CallLoc))
4186 CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data());
4188 // For a trivial copy or move assignment, perform an APValue copy. This is
4189 // essential for unions, where the operations performed by the assignment
4190 // operator cannot be represented as statements.
4192 // Skip this for non-union classes with no fields; in that case, the defaulted
4193 // copy/move does not actually read the object.
4194 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee);
4195 if (MD && MD->isDefaulted() &&
4196 (MD->getParent()->isUnion() ||
4197 (MD->isTrivial() && hasFields(MD->getParent())))) {
4199 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()));
4201 RHS.setFrom(Info.Ctx, ArgValues[0]);
4203 if (!handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(),
4206 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(Info.Ctx),
4209 This->moveInto(Result);
4211 } else if (MD && isLambdaCallOperator(MD)) {
4212 // We're in a lambda; determine the lambda capture field maps.
4213 MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields,
4214 Frame.LambdaThisCaptureField);
4217 StmtResult Ret = {Result, ResultSlot};
4218 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body);
4219 if (ESR == ESR_Succeeded) {
4220 if (Callee->getReturnType()->isVoidType())
4222 Info.FFDiag(Callee->getLocEnd(), diag::note_constexpr_no_return);
4224 return ESR == ESR_Returned;
4227 /// Evaluate a constructor call.
4228 static bool HandleConstructorCall(const Expr *E, const LValue &This,
4230 const CXXConstructorDecl *Definition,
4231 EvalInfo &Info, APValue &Result) {
4232 SourceLocation CallLoc = E->getExprLoc();
4233 if (!Info.CheckCallLimit(CallLoc))
4236 const CXXRecordDecl *RD = Definition->getParent();
4237 if (RD->getNumVBases()) {
4238 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
4242 CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues);
4244 // FIXME: Creating an APValue just to hold a nonexistent return value is
4247 StmtResult Ret = {RetVal, nullptr};
4249 // If it's a delegating constructor, delegate.
4250 if (Definition->isDelegatingConstructor()) {
4251 CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
4253 FullExpressionRAII InitScope(Info);
4254 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()))
4257 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
4260 // For a trivial copy or move constructor, perform an APValue copy. This is
4261 // essential for unions (or classes with anonymous union members), where the
4262 // operations performed by the constructor cannot be represented by
4263 // ctor-initializers.
4265 // Skip this for empty non-union classes; we should not perform an
4266 // lvalue-to-rvalue conversion on them because their copy constructor does not
4267 // actually read them.
4268 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
4269 (Definition->getParent()->isUnion() ||
4270 (Definition->isTrivial() && hasFields(Definition->getParent())))) {
4272 RHS.setFrom(Info.Ctx, ArgValues[0]);
4273 return handleLValueToRValueConversion(
4274 Info, E, Definition->getParamDecl(0)->getType().getNonReferenceType(),
4278 // Reserve space for the struct members.
4279 if (!RD->isUnion() && Result.isUninit())
4280 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
4281 std::distance(RD->field_begin(), RD->field_end()));
4283 if (RD->isInvalidDecl()) return false;
4284 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
4286 // A scope for temporaries lifetime-extended by reference members.
4287 BlockScopeRAII LifetimeExtendedScope(Info);
4289 bool Success = true;
4290 unsigned BasesSeen = 0;
4292 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
4294 for (const auto *I : Definition->inits()) {
4295 LValue Subobject = This;
4296 APValue *Value = &Result;
4298 // Determine the subobject to initialize.
4299 FieldDecl *FD = nullptr;
4300 if (I->isBaseInitializer()) {
4301 QualType BaseType(I->getBaseClass(), 0);
4303 // Non-virtual base classes are initialized in the order in the class
4304 // definition. We have already checked for virtual base classes.
4305 assert(!BaseIt->isVirtual() && "virtual base for literal type");
4306 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
4307 "base class initializers not in expected order");
4310 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD,
4311 BaseType->getAsCXXRecordDecl(), &Layout))
4313 Value = &Result.getStructBase(BasesSeen++);
4314 } else if ((FD = I->getMember())) {
4315 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout))
4317 if (RD->isUnion()) {
4318 Result = APValue(FD);
4319 Value = &Result.getUnionValue();
4321 Value = &Result.getStructField(FD->getFieldIndex());
4323 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
4324 // Walk the indirect field decl's chain to find the object to initialize,
4325 // and make sure we've initialized every step along it.
4326 for (auto *C : IFD->chain()) {
4327 FD = cast<FieldDecl>(C);
4328 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
4329 // Switch the union field if it differs. This happens if we had
4330 // preceding zero-initialization, and we're now initializing a union
4331 // subobject other than the first.
4332 // FIXME: In this case, the values of the other subobjects are
4333 // specified, since zero-initialization sets all padding bits to zero.
4334 if (Value->isUninit() ||
4335 (Value->isUnion() && Value->getUnionField() != FD)) {
4337 *Value = APValue(FD);
4339 *Value = APValue(APValue::UninitStruct(), CD->getNumBases(),
4340 std::distance(CD->field_begin(), CD->field_end()));
4342 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
4345 Value = &Value->getUnionValue();
4347 Value = &Value->getStructField(FD->getFieldIndex());
4350 llvm_unreachable("unknown base initializer kind");
4353 FullExpressionRAII InitScope(Info);
4354 if (!EvaluateInPlace(*Value, Info, Subobject, I->getInit()) ||
4355 (FD && FD->isBitField() && !truncateBitfieldValue(Info, I->getInit(),
4357 // If we're checking for a potential constant expression, evaluate all
4358 // initializers even if some of them fail.
4359 if (!Info.noteFailure())
4366 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
4369 static bool HandleConstructorCall(const Expr *E, const LValue &This,
4370 ArrayRef<const Expr*> Args,
4371 const CXXConstructorDecl *Definition,
4372 EvalInfo &Info, APValue &Result) {
4373 ArgVector ArgValues(Args.size());
4374 if (!EvaluateArgs(Args, ArgValues, Info))
4377 return HandleConstructorCall(E, This, ArgValues.data(), Definition,
4381 //===----------------------------------------------------------------------===//
4382 // Generic Evaluation
4383 //===----------------------------------------------------------------------===//
4386 template <class Derived>
4387 class ExprEvaluatorBase
4388 : public ConstStmtVisitor<Derived, bool> {
4390 Derived &getDerived() { return static_cast<Derived&>(*this); }
4391 bool DerivedSuccess(const APValue &V, const Expr *E) {
4392 return getDerived().Success(V, E);
4394 bool DerivedZeroInitialization(const Expr *E) {
4395 return getDerived().ZeroInitialization(E);
4398 // Check whether a conditional operator with a non-constant condition is a
4399 // potential constant expression. If neither arm is a potential constant
4400 // expression, then the conditional operator is not either.
4401 template<typename ConditionalOperator>
4402 void CheckPotentialConstantConditional(const ConditionalOperator *E) {
4403 assert(Info.checkingPotentialConstantExpression());
4405 // Speculatively evaluate both arms.
4406 SmallVector<PartialDiagnosticAt, 8> Diag;
4408 SpeculativeEvaluationRAII Speculate(Info, &Diag);
4409 StmtVisitorTy::Visit(E->getFalseExpr());
4415 SpeculativeEvaluationRAII Speculate(Info, &Diag);
4417 StmtVisitorTy::Visit(E->getTrueExpr());
4422 Error(E, diag::note_constexpr_conditional_never_const);
4426 template<typename ConditionalOperator>
4427 bool HandleConditionalOperator(const ConditionalOperator *E) {
4429 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
4430 if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) {
4431 CheckPotentialConstantConditional(E);
4434 if (Info.noteFailure()) {
4435 StmtVisitorTy::Visit(E->getTrueExpr());
4436 StmtVisitorTy::Visit(E->getFalseExpr());
4441 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
4442 return StmtVisitorTy::Visit(EvalExpr);
4447 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
4448 typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
4450 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
4451 return Info.CCEDiag(E, D);
4454 bool ZeroInitialization(const Expr *E) { return Error(E); }
4457 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
4459 EvalInfo &getEvalInfo() { return Info; }
4461 /// Report an evaluation error. This should only be called when an error is
4462 /// first discovered. When propagating an error, just return false.
4463 bool Error(const Expr *E, diag::kind D) {
4467 bool Error(const Expr *E) {
4468 return Error(E, diag::note_invalid_subexpr_in_const_expr);
4471 bool VisitStmt(const Stmt *) {
4472 llvm_unreachable("Expression evaluator should not be called on stmts");
4474 bool VisitExpr(const Expr *E) {
4478 bool VisitParenExpr(const ParenExpr *E)
4479 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4480 bool VisitUnaryExtension(const UnaryOperator *E)
4481 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4482 bool VisitUnaryPlus(const UnaryOperator *E)
4483 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4484 bool VisitChooseExpr(const ChooseExpr *E)
4485 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
4486 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
4487 { return StmtVisitorTy::Visit(E->getResultExpr()); }
4488 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
4489 { return StmtVisitorTy::Visit(E->getReplacement()); }
4490 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E)
4491 { return StmtVisitorTy::Visit(E->getExpr()); }
4492 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
4493 // The initializer may not have been parsed yet, or might be erroneous.
4496 return StmtVisitorTy::Visit(E->getExpr());
4498 // We cannot create any objects for which cleanups are required, so there is
4499 // nothing to do here; all cleanups must come from unevaluated subexpressions.
4500 bool VisitExprWithCleanups(const ExprWithCleanups *E)
4501 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4503 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
4504 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
4505 return static_cast<Derived*>(this)->VisitCastExpr(E);
4507 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
4508 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
4509 return static_cast<Derived*>(this)->VisitCastExpr(E);
4512 bool VisitBinaryOperator(const BinaryOperator *E) {
4513 switch (E->getOpcode()) {
4518 VisitIgnoredValue(E->getLHS());
4519 return StmtVisitorTy::Visit(E->getRHS());
4524 if (!HandleMemberPointerAccess(Info, E, Obj))
4527 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
4529 return DerivedSuccess(Result, E);
4534 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
4535 // Evaluate and cache the common expression. We treat it as a temporary,
4536 // even though it's not quite the same thing.
4537 if (!Evaluate(Info.CurrentCall->createTemporary(E->getOpaqueValue(), false),
4538 Info, E->getCommon()))
4541 return HandleConditionalOperator(E);
4544 bool VisitConditionalOperator(const ConditionalOperator *E) {
4545 bool IsBcpCall = false;
4546 // If the condition (ignoring parens) is a __builtin_constant_p call,
4547 // the result is a constant expression if it can be folded without
4548 // side-effects. This is an important GNU extension. See GCC PR38377
4550 if (const CallExpr *CallCE =
4551 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
4552 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
4555 // Always assume __builtin_constant_p(...) ? ... : ... is a potential
4556 // constant expression; we can't check whether it's potentially foldable.
4557 if (Info.checkingPotentialConstantExpression() && IsBcpCall)
4560 FoldConstant Fold(Info, IsBcpCall);
4561 if (!HandleConditionalOperator(E)) {
4562 Fold.keepDiagnostics();
4569 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
4570 if (APValue *Value = Info.CurrentCall->getTemporary(E))
4571 return DerivedSuccess(*Value, E);
4573 const Expr *Source = E->getSourceExpr();
4576 if (Source == E) { // sanity checking.
4577 assert(0 && "OpaqueValueExpr recursively refers to itself");
4580 return StmtVisitorTy::Visit(Source);
4583 bool VisitCallExpr(const CallExpr *E) {
4585 if (!handleCallExpr(E, Result, nullptr))
4587 return DerivedSuccess(Result, E);
4590 bool handleCallExpr(const CallExpr *E, APValue &Result,
4591 const LValue *ResultSlot) {
4592 const Expr *Callee = E->getCallee()->IgnoreParens();
4593 QualType CalleeType = Callee->getType();
4595 const FunctionDecl *FD = nullptr;
4596 LValue *This = nullptr, ThisVal;
4597 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
4598 bool HasQualifier = false;
4600 struct EvaluateIgnoredRAII {
4602 EvaluateIgnoredRAII(EvalInfo &Info, llvm::ArrayRef<const Expr*> ToEval)
4603 : Info(Info), ToEval(ToEval) {}
4604 ~EvaluateIgnoredRAII() {
4605 if (Info.noteFailure()) {
4606 for (auto E : ToEval)
4607 EvaluateIgnoredValue(Info, E);
4610 void cancel() { ToEval = {}; }
4611 void drop_front() { ToEval = ToEval.drop_front(); }
4614 llvm::ArrayRef<const Expr*> ToEval;
4615 } EvalArguments(Info, Args);
4617 // Extract function decl and 'this' pointer from the callee.
4618 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
4619 const ValueDecl *Member = nullptr;
4620 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
4621 // Explicit bound member calls, such as x.f() or p->g();
4622 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
4624 Member = ME->getMemberDecl();
4626 HasQualifier = ME->hasQualifier();
4627 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
4628 // Indirect bound member calls ('.*' or '->*').
4629 Member = HandleMemberPointerAccess(Info, BE, ThisVal, false);
4630 if (!Member) return false;
4633 return Error(Callee);
4635 FD = dyn_cast<FunctionDecl>(Member);
4637 return Error(Callee);
4638 } else if (CalleeType->isFunctionPointerType()) {
4640 if (!EvaluatePointer(Callee, Call, Info))
4643 if (!Call.getLValueOffset().isZero())
4644 return Error(Callee);
4645 FD = dyn_cast_or_null<FunctionDecl>(
4646 Call.getLValueBase().dyn_cast<const ValueDecl*>());
4648 return Error(Callee);
4649 // Don't call function pointers which have been cast to some other type.
4650 // Per DR (no number yet), the caller and callee can differ in noexcept.
4651 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
4652 CalleeType->getPointeeType(), FD->getType())) {
4656 // Overloaded operator calls to member functions are represented as normal
4657 // calls with '*this' as the first argument.
4658 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
4659 if (MD && !MD->isStatic()) {
4660 // FIXME: When selecting an implicit conversion for an overloaded
4661 // operator delete, we sometimes try to evaluate calls to conversion
4662 // operators without a 'this' parameter!
4666 const Expr *FirstArg = Args[0];
4667 Args = Args.drop_front();
4668 EvalArguments.drop_front();
4669 if (!EvaluateObjectArgument(Info, FirstArg, ThisVal))
4672 } else if (MD && MD->isLambdaStaticInvoker()) {
4673 // Map the static invoker for the lambda back to the call operator.
4674 // Conveniently, we don't have to slice out the 'this' argument (as is
4675 // being done for the non-static case), since a static member function
4676 // doesn't have an implicit argument passed in.
4677 const CXXRecordDecl *ClosureClass = MD->getParent();
4679 ClosureClass->captures_begin() == ClosureClass->captures_end() &&
4680 "Number of captures must be zero for conversion to function-ptr");
4682 const CXXMethodDecl *LambdaCallOp =
4683 ClosureClass->getLambdaCallOperator();
4685 // Set 'FD', the function that will be called below, to the call
4686 // operator. If the closure object represents a generic lambda, find
4687 // the corresponding specialization of the call operator.
4689 if (ClosureClass->isGenericLambda()) {
4690 assert(MD->isFunctionTemplateSpecialization() &&
4691 "A generic lambda's static-invoker function must be a "
4692 "template specialization");
4693 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
4694 FunctionTemplateDecl *CallOpTemplate =
4695 LambdaCallOp->getDescribedFunctionTemplate();
4696 void *InsertPos = nullptr;
4697 FunctionDecl *CorrespondingCallOpSpecialization =
4698 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
4699 assert(CorrespondingCallOpSpecialization &&
4700 "We must always have a function call operator specialization "
4701 "that corresponds to our static invoker specialization");
4702 FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
4711 if (This && !This->checkSubobject(Info, E, CSK_This))
4714 // DR1358 allows virtual constexpr functions in some cases. Don't allow
4715 // calls to such functions in constant expressions.
4716 if (This && !HasQualifier &&
4717 isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isVirtual())
4718 return Error(E, diag::note_constexpr_virtual_call);
4720 const FunctionDecl *Definition = nullptr;
4721 Stmt *Body = FD->getBody(Definition);
4723 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
4726 EvalArguments.cancel();
4728 if (!HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, Info,
4729 Result, ResultSlot))
4735 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
4736 return StmtVisitorTy::Visit(E->getInitializer());
4738 bool VisitInitListExpr(const InitListExpr *E) {
4739 if (E->getNumInits() == 0)
4740 return DerivedZeroInitialization(E);
4741 if (E->getNumInits() == 1)
4742 return StmtVisitorTy::Visit(E->getInit(0));
4745 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
4746 return DerivedZeroInitialization(E);
4748 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
4749 return DerivedZeroInitialization(E);
4751 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
4752 return DerivedZeroInitialization(E);
4755 /// A member expression where the object is a prvalue is itself a prvalue.
4756 bool VisitMemberExpr(const MemberExpr *E) {
4757 assert(!E->isArrow() && "missing call to bound member function?");
4760 if (!Evaluate(Val, Info, E->getBase()))
4763 QualType BaseTy = E->getBase()->getType();
4765 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
4766 if (!FD) return Error(E);
4767 assert(!FD->getType()->isReferenceType() && "prvalue reference?");
4768 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
4769 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
4771 CompleteObject Obj(&Val, BaseTy);
4772 SubobjectDesignator Designator(BaseTy);
4773 Designator.addDeclUnchecked(FD);
4776 return extractSubobject(Info, E, Obj, Designator, Result) &&
4777 DerivedSuccess(Result, E);
4780 bool VisitCastExpr(const CastExpr *E) {
4781 switch (E->getCastKind()) {
4785 case CK_AtomicToNonAtomic: {
4787 // This does not need to be done in place even for class/array types:
4788 // atomic-to-non-atomic conversion implies copying the object
4790 if (!Evaluate(AtomicVal, Info, E->getSubExpr()))
4792 return DerivedSuccess(AtomicVal, E);
4796 case CK_UserDefinedConversion:
4797 return StmtVisitorTy::Visit(E->getSubExpr());
4799 case CK_LValueToRValue: {
4801 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
4804 // Note, we use the subexpression's type in order to retain cv-qualifiers.
4805 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
4808 return DerivedSuccess(RVal, E);
4815 bool VisitUnaryPostInc(const UnaryOperator *UO) {
4816 return VisitUnaryPostIncDec(UO);
4818 bool VisitUnaryPostDec(const UnaryOperator *UO) {
4819 return VisitUnaryPostIncDec(UO);
4821 bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
4822 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
4826 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info))
4829 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
4830 UO->isIncrementOp(), &RVal))
4832 return DerivedSuccess(RVal, UO);
4835 bool VisitStmtExpr(const StmtExpr *E) {
4836 // We will have checked the full-expressions inside the statement expression
4837 // when they were completed, and don't need to check them again now.
4838 if (Info.checkingForOverflow())
4841 BlockScopeRAII Scope(Info);
4842 const CompoundStmt *CS = E->getSubStmt();
4843 if (CS->body_empty())
4846 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
4847 BE = CS->body_end();
4850 const Expr *FinalExpr = dyn_cast<Expr>(*BI);
4852 Info.FFDiag((*BI)->getLocStart(),
4853 diag::note_constexpr_stmt_expr_unsupported);
4856 return this->Visit(FinalExpr);
4859 APValue ReturnValue;
4860 StmtResult Result = { ReturnValue, nullptr };
4861 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
4862 if (ESR != ESR_Succeeded) {
4863 // FIXME: If the statement-expression terminated due to 'return',
4864 // 'break', or 'continue', it would be nice to propagate that to
4865 // the outer statement evaluation rather than bailing out.
4866 if (ESR != ESR_Failed)
4867 Info.FFDiag((*BI)->getLocStart(),
4868 diag::note_constexpr_stmt_expr_unsupported);
4873 llvm_unreachable("Return from function from the loop above.");
4876 /// Visit a value which is evaluated, but whose value is ignored.
4877 void VisitIgnoredValue(const Expr *E) {
4878 EvaluateIgnoredValue(Info, E);
4881 /// Potentially visit a MemberExpr's base expression.
4882 void VisitIgnoredBaseExpression(const Expr *E) {
4883 // While MSVC doesn't evaluate the base expression, it does diagnose the
4884 // presence of side-effecting behavior.
4885 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
4887 VisitIgnoredValue(E);
4893 //===----------------------------------------------------------------------===//
4894 // Common base class for lvalue and temporary evaluation.
4895 //===----------------------------------------------------------------------===//
4897 template<class Derived>
4898 class LValueExprEvaluatorBase
4899 : public ExprEvaluatorBase<Derived> {
4903 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
4904 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
4906 bool Success(APValue::LValueBase B) {
4911 bool evaluatePointer(const Expr *E, LValue &Result) {
4912 return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
4916 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
4917 : ExprEvaluatorBaseTy(Info), Result(Result),
4918 InvalidBaseOK(InvalidBaseOK) {}
4920 bool Success(const APValue &V, const Expr *E) {
4921 Result.setFrom(this->Info.Ctx, V);
4925 bool VisitMemberExpr(const MemberExpr *E) {
4926 // Handle non-static data members.
4930 EvalOK = evaluatePointer(E->getBase(), Result);
4931 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
4932 } else if (E->getBase()->isRValue()) {
4933 assert(E->getBase()->getType()->isRecordType());
4934 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
4935 BaseTy = E->getBase()->getType();
4937 EvalOK = this->Visit(E->getBase());
4938 BaseTy = E->getBase()->getType();
4943 Result.setInvalid(E);
4947 const ValueDecl *MD = E->getMemberDecl();
4948 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
4949 assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() ==
4950 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
4952 if (!HandleLValueMember(this->Info, E, Result, FD))
4954 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
4955 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
4958 return this->Error(E);
4960 if (MD->getType()->isReferenceType()) {
4962 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
4965 return Success(RefValue, E);
4970 bool VisitBinaryOperator(const BinaryOperator *E) {
4971 switch (E->getOpcode()) {
4973 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
4977 return HandleMemberPointerAccess(this->Info, E, Result);
4981 bool VisitCastExpr(const CastExpr *E) {
4982 switch (E->getCastKind()) {
4984 return ExprEvaluatorBaseTy::VisitCastExpr(E);
4986 case CK_DerivedToBase:
4987 case CK_UncheckedDerivedToBase:
4988 if (!this->Visit(E->getSubExpr()))
4991 // Now figure out the necessary offset to add to the base LV to get from
4992 // the derived class to the base class.
4993 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
5000 //===----------------------------------------------------------------------===//
5001 // LValue Evaluation
5003 // This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
5004 // function designators (in C), decl references to void objects (in C), and
5005 // temporaries (if building with -Wno-address-of-temporary).
5007 // LValue evaluation produces values comprising a base expression of one of the
5013 // * CompoundLiteralExpr in C (and in global scope in C++)
5017 // * ObjCStringLiteralExpr
5021 // * CallExpr for a MakeStringConstant builtin
5022 // - Locals and temporaries
5023 // * MaterializeTemporaryExpr
5024 // * Any Expr, with a CallIndex indicating the function in which the temporary
5025 // was evaluated, for cases where the MaterializeTemporaryExpr is missing
5026 // from the AST (FIXME).
5027 // * A MaterializeTemporaryExpr that has static storage duration, with no
5028 // CallIndex, for a lifetime-extended temporary.
5029 // plus an offset in bytes.
5030 //===----------------------------------------------------------------------===//
5032 class LValueExprEvaluator
5033 : public LValueExprEvaluatorBase<LValueExprEvaluator> {
5035 LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
5036 LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}
5038 bool VisitVarDecl(const Expr *E, const VarDecl *VD);
5039 bool VisitUnaryPreIncDec(const UnaryOperator *UO);
5041 bool VisitDeclRefExpr(const DeclRefExpr *E);
5042 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
5043 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
5044 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
5045 bool VisitMemberExpr(const MemberExpr *E);
5046 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
5047 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
5048 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
5049 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
5050 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
5051 bool VisitUnaryDeref(const UnaryOperator *E);
5052 bool VisitUnaryReal(const UnaryOperator *E);
5053 bool VisitUnaryImag(const UnaryOperator *E);
5054 bool VisitUnaryPreInc(const UnaryOperator *UO) {
5055 return VisitUnaryPreIncDec(UO);
5057 bool VisitUnaryPreDec(const UnaryOperator *UO) {
5058 return VisitUnaryPreIncDec(UO);
5060 bool VisitBinAssign(const BinaryOperator *BO);
5061 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
5063 bool VisitCastExpr(const CastExpr *E) {
5064 switch (E->getCastKind()) {
5066 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
5068 case CK_LValueBitCast:
5069 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5070 if (!Visit(E->getSubExpr()))
5072 Result.Designator.setInvalid();
5075 case CK_BaseToDerived:
5076 if (!Visit(E->getSubExpr()))
5078 return HandleBaseToDerivedCast(Info, E, Result);
5082 } // end anonymous namespace
5084 /// Evaluate an expression as an lvalue. This can be legitimately called on
5085 /// expressions which are not glvalues, in three cases:
5086 /// * function designators in C, and
5087 /// * "extern void" objects
5088 /// * @selector() expressions in Objective-C
5089 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
5090 bool InvalidBaseOK) {
5091 assert(E->isGLValue() || E->getType()->isFunctionType() ||
5092 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E));
5093 return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
5096 bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
5097 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl()))
5099 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
5100 return VisitVarDecl(E, VD);
5101 if (const BindingDecl *BD = dyn_cast<BindingDecl>(E->getDecl()))
5102 return Visit(BD->getBinding());
5107 bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
5109 // If we are within a lambda's call operator, check whether the 'VD' referred
5110 // to within 'E' actually represents a lambda-capture that maps to a
5111 // data-member/field within the closure object, and if so, evaluate to the
5112 // field or what the field refers to.
5113 if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee)) {
5114 if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) {
5115 if (Info.checkingPotentialConstantExpression())
5117 // Start with 'Result' referring to the complete closure object...
5118 Result = *Info.CurrentCall->This;
5119 // ... then update it to refer to the field of the closure object
5120 // that represents the capture.
5121 if (!HandleLValueMember(Info, E, Result, FD))
5123 // And if the field is of reference type, update 'Result' to refer to what
5124 // the field refers to.
5125 if (FD->getType()->isReferenceType()) {
5127 if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result,
5130 Result.setFrom(Info.Ctx, RVal);
5135 CallStackFrame *Frame = nullptr;
5136 if (VD->hasLocalStorage() && Info.CurrentCall->Index > 1) {
5137 // Only if a local variable was declared in the function currently being
5138 // evaluated, do we expect to be able to find its value in the current
5139 // frame. (Otherwise it was likely declared in an enclosing context and
5140 // could either have a valid evaluatable value (for e.g. a constexpr
5141 // variable) or be ill-formed (and trigger an appropriate evaluation
5143 if (Info.CurrentCall->Callee &&
5144 Info.CurrentCall->Callee->Equals(VD->getDeclContext())) {
5145 Frame = Info.CurrentCall;
5149 if (!VD->getType()->isReferenceType()) {
5151 Result.set(VD, Frame->Index);
5158 if (!evaluateVarDeclInit(Info, E, VD, Frame, V))
5160 if (V->isUninit()) {
5161 if (!Info.checkingPotentialConstantExpression())
5162 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
5165 return Success(*V, E);
5168 bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
5169 const MaterializeTemporaryExpr *E) {
5170 // Walk through the expression to find the materialized temporary itself.
5171 SmallVector<const Expr *, 2> CommaLHSs;
5172 SmallVector<SubobjectAdjustment, 2> Adjustments;
5173 const Expr *Inner = E->GetTemporaryExpr()->
5174 skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
5176 // If we passed any comma operators, evaluate their LHSs.
5177 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
5178 if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
5181 // A materialized temporary with static storage duration can appear within the
5182 // result of a constant expression evaluation, so we need to preserve its
5183 // value for use outside this evaluation.
5185 if (E->getStorageDuration() == SD_Static) {
5186 Value = Info.Ctx.getMaterializedTemporaryValue(E, true);
5190 Value = &Info.CurrentCall->
5191 createTemporary(E, E->getStorageDuration() == SD_Automatic);
5192 Result.set(E, Info.CurrentCall->Index);
5195 QualType Type = Inner->getType();
5197 // Materialize the temporary itself.
5198 if (!EvaluateInPlace(*Value, Info, Result, Inner) ||
5199 (E->getStorageDuration() == SD_Static &&
5200 !CheckConstantExpression(Info, E->getExprLoc(), Type, *Value))) {
5205 // Adjust our lvalue to refer to the desired subobject.
5206 for (unsigned I = Adjustments.size(); I != 0; /**/) {
5208 switch (Adjustments[I].Kind) {
5209 case SubobjectAdjustment::DerivedToBaseAdjustment:
5210 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath,
5213 Type = Adjustments[I].DerivedToBase.BasePath->getType();
5216 case SubobjectAdjustment::FieldAdjustment:
5217 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
5219 Type = Adjustments[I].Field->getType();
5222 case SubobjectAdjustment::MemberPointerAdjustment:
5223 if (!HandleMemberPointerAccess(this->Info, Type, Result,
5224 Adjustments[I].Ptr.RHS))
5226 Type = Adjustments[I].Ptr.MPT->getPointeeType();
5235 LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
5236 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
5237 "lvalue compound literal in c++?");
5238 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
5239 // only see this when folding in C, so there's no standard to follow here.
5243 bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
5244 if (!E->isPotentiallyEvaluated())
5247 Info.FFDiag(E, diag::note_constexpr_typeid_polymorphic)
5248 << E->getExprOperand()->getType()
5249 << E->getExprOperand()->getSourceRange();
5253 bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
5257 bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
5258 // Handle static data members.
5259 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
5260 VisitIgnoredBaseExpression(E->getBase());
5261 return VisitVarDecl(E, VD);
5264 // Handle static member functions.
5265 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
5266 if (MD->isStatic()) {
5267 VisitIgnoredBaseExpression(E->getBase());
5272 // Handle non-static data members.
5273 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
5276 bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
5277 // FIXME: Deal with vectors as array subscript bases.
5278 if (E->getBase()->getType()->isVectorType())
5281 bool Success = true;
5282 if (!evaluatePointer(E->getBase(), Result)) {
5283 if (!Info.noteFailure())
5289 if (!EvaluateInteger(E->getIdx(), Index, Info))
5293 HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index);
5296 bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
5297 return evaluatePointer(E->getSubExpr(), Result);
5300 bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
5301 if (!Visit(E->getSubExpr()))
5303 // __real is a no-op on scalar lvalues.
5304 if (E->getSubExpr()->getType()->isAnyComplexType())
5305 HandleLValueComplexElement(Info, E, Result, E->getType(), false);
5309 bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
5310 assert(E->getSubExpr()->getType()->isAnyComplexType() &&
5311 "lvalue __imag__ on scalar?");
5312 if (!Visit(E->getSubExpr()))
5314 HandleLValueComplexElement(Info, E, Result, E->getType(), true);
5318 bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
5319 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5322 if (!this->Visit(UO->getSubExpr()))
5325 return handleIncDec(
5326 this->Info, UO, Result, UO->getSubExpr()->getType(),
5327 UO->isIncrementOp(), nullptr);
5330 bool LValueExprEvaluator::VisitCompoundAssignOperator(
5331 const CompoundAssignOperator *CAO) {
5332 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5337 // The overall lvalue result is the result of evaluating the LHS.
5338 if (!this->Visit(CAO->getLHS())) {
5339 if (Info.noteFailure())
5340 Evaluate(RHS, this->Info, CAO->getRHS());
5344 if (!Evaluate(RHS, this->Info, CAO->getRHS()))
5347 return handleCompoundAssignment(
5349 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
5350 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS);
5353 bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
5354 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5359 if (!this->Visit(E->getLHS())) {
5360 if (Info.noteFailure())
5361 Evaluate(NewVal, this->Info, E->getRHS());
5365 if (!Evaluate(NewVal, this->Info, E->getRHS()))
5368 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
5372 //===----------------------------------------------------------------------===//
5373 // Pointer Evaluation
5374 //===----------------------------------------------------------------------===//
5376 /// \brief Attempts to compute the number of bytes available at the pointer
5377 /// returned by a function with the alloc_size attribute. Returns true if we
5378 /// were successful. Places an unsigned number into `Result`.
5380 /// This expects the given CallExpr to be a call to a function with an
5381 /// alloc_size attribute.
5382 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
5383 const CallExpr *Call,
5384 llvm::APInt &Result) {
5385 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
5387 // alloc_size args are 1-indexed, 0 means not present.
5388 assert(AllocSize && AllocSize->getElemSizeParam() != 0);
5389 unsigned SizeArgNo = AllocSize->getElemSizeParam() - 1;
5390 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
5391 if (Call->getNumArgs() <= SizeArgNo)
5394 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
5395 if (!E->EvaluateAsInt(Into, Ctx, Expr::SE_AllowSideEffects))
5397 if (Into.isNegative() || !Into.isIntN(BitsInSizeT))
5399 Into = Into.zextOrSelf(BitsInSizeT);
5404 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
5407 if (!AllocSize->getNumElemsParam()) {
5408 Result = std::move(SizeOfElem);
5412 APSInt NumberOfElems;
5413 // Argument numbers start at 1
5414 unsigned NumArgNo = AllocSize->getNumElemsParam() - 1;
5415 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
5419 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow);
5423 Result = std::move(BytesAvailable);
5427 /// \brief Convenience function. LVal's base must be a call to an alloc_size
5429 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
5431 llvm::APInt &Result) {
5432 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
5433 "Can't get the size of a non alloc_size function");
5434 const auto *Base = LVal.getLValueBase().get<const Expr *>();
5435 const CallExpr *CE = tryUnwrapAllocSizeCall(Base);
5436 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result);
5439 /// \brief Attempts to evaluate the given LValueBase as the result of a call to
5440 /// a function with the alloc_size attribute. If it was possible to do so, this
5441 /// function will return true, make Result's Base point to said function call,
5442 /// and mark Result's Base as invalid.
5443 static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
5448 // Because we do no form of static analysis, we only support const variables.
5450 // Additionally, we can't support parameters, nor can we support static
5451 // variables (in the latter case, use-before-assign isn't UB; in the former,
5452 // we have no clue what they'll be assigned to).
5454 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>());
5455 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
5458 const Expr *Init = VD->getAnyInitializer();
5462 const Expr *E = Init->IgnoreParens();
5463 if (!tryUnwrapAllocSizeCall(E))
5466 // Store E instead of E unwrapped so that the type of the LValue's base is
5467 // what the user wanted.
5468 Result.setInvalid(E);
5470 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
5471 Result.addUnsizedArray(Info, Pointee);
5476 class PointerExprEvaluator
5477 : public ExprEvaluatorBase<PointerExprEvaluator> {
5481 bool Success(const Expr *E) {
5486 bool evaluateLValue(const Expr *E, LValue &Result) {
5487 return EvaluateLValue(E, Result, Info, InvalidBaseOK);
5490 bool evaluatePointer(const Expr *E, LValue &Result) {
5491 return EvaluatePointer(E, Result, Info, InvalidBaseOK);
5494 bool visitNonBuiltinCallExpr(const CallExpr *E);
5497 PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
5498 : ExprEvaluatorBaseTy(info), Result(Result),
5499 InvalidBaseOK(InvalidBaseOK) {}
5501 bool Success(const APValue &V, const Expr *E) {
5502 Result.setFrom(Info.Ctx, V);
5505 bool ZeroInitialization(const Expr *E) {
5506 auto TargetVal = Info.Ctx.getTargetNullPointerValue(E->getType());
5507 Result.setNull(E->getType(), TargetVal);
5511 bool VisitBinaryOperator(const BinaryOperator *E);
5512 bool VisitCastExpr(const CastExpr* E);
5513 bool VisitUnaryAddrOf(const UnaryOperator *E);
5514 bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
5515 { return Success(E); }
5516 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
5517 if (Info.noteFailure())
5518 EvaluateIgnoredValue(Info, E->getSubExpr());
5521 bool VisitAddrLabelExpr(const AddrLabelExpr *E)
5522 { return Success(E); }
5523 bool VisitCallExpr(const CallExpr *E);
5524 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
5525 bool VisitBlockExpr(const BlockExpr *E) {
5526 if (!E->getBlockDecl()->hasCaptures())
5530 bool VisitCXXThisExpr(const CXXThisExpr *E) {
5531 // Can't look at 'this' when checking a potential constant expression.
5532 if (Info.checkingPotentialConstantExpression())
5534 if (!Info.CurrentCall->This) {
5535 if (Info.getLangOpts().CPlusPlus11)
5536 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
5541 Result = *Info.CurrentCall->This;
5542 // If we are inside a lambda's call operator, the 'this' expression refers
5543 // to the enclosing '*this' object (either by value or reference) which is
5544 // either copied into the closure object's field that represents the '*this'
5545 // or refers to '*this'.
5546 if (isLambdaCallOperator(Info.CurrentCall->Callee)) {
5547 // Update 'Result' to refer to the data member/field of the closure object
5548 // that represents the '*this' capture.
5549 if (!HandleLValueMember(Info, E, Result,
5550 Info.CurrentCall->LambdaThisCaptureField))
5552 // If we captured '*this' by reference, replace the field with its referent.
5553 if (Info.CurrentCall->LambdaThisCaptureField->getType()
5554 ->isPointerType()) {
5556 if (!handleLValueToRValueConversion(Info, E, E->getType(), Result,
5560 Result.setFrom(Info.Ctx, RVal);
5566 // FIXME: Missing: @protocol, @selector
5568 } // end anonymous namespace
5570 static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
5571 bool InvalidBaseOK) {
5572 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
5573 return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
5576 bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
5577 if (E->getOpcode() != BO_Add &&
5578 E->getOpcode() != BO_Sub)
5579 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
5581 const Expr *PExp = E->getLHS();
5582 const Expr *IExp = E->getRHS();
5583 if (IExp->getType()->isPointerType())
5584 std::swap(PExp, IExp);
5586 bool EvalPtrOK = evaluatePointer(PExp, Result);
5587 if (!EvalPtrOK && !Info.noteFailure())
5590 llvm::APSInt Offset;
5591 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
5594 if (E->getOpcode() == BO_Sub)
5595 negateAsSigned(Offset);
5597 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
5598 return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset);
5601 bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
5602 return evaluateLValue(E->getSubExpr(), Result);
5605 bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
5606 const Expr* SubExpr = E->getSubExpr();
5608 switch (E->getCastKind()) {
5613 case CK_CPointerToObjCPointerCast:
5614 case CK_BlockPointerToObjCPointerCast:
5615 case CK_AnyPointerToBlockPointerCast:
5616 case CK_AddressSpaceConversion:
5617 if (!Visit(SubExpr))
5619 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
5620 // permitted in constant expressions in C++11. Bitcasts from cv void* are
5621 // also static_casts, but we disallow them as a resolution to DR1312.
5622 if (!E->getType()->isVoidPointerType()) {
5623 Result.Designator.setInvalid();
5624 if (SubExpr->getType()->isVoidPointerType())
5625 CCEDiag(E, diag::note_constexpr_invalid_cast)
5626 << 3 << SubExpr->getType();
5628 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5630 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
5631 ZeroInitialization(E);
5634 case CK_DerivedToBase:
5635 case CK_UncheckedDerivedToBase:
5636 if (!evaluatePointer(E->getSubExpr(), Result))
5638 if (!Result.Base && Result.Offset.isZero())
5641 // Now figure out the necessary offset to add to the base LV to get from
5642 // the derived class to the base class.
5643 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()->
5644 castAs<PointerType>()->getPointeeType(),
5647 case CK_BaseToDerived:
5648 if (!Visit(E->getSubExpr()))
5650 if (!Result.Base && Result.Offset.isZero())
5652 return HandleBaseToDerivedCast(Info, E, Result);
5654 case CK_NullToPointer:
5655 VisitIgnoredValue(E->getSubExpr());
5656 return ZeroInitialization(E);
5658 case CK_IntegralToPointer: {
5659 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5662 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
5665 if (Value.isInt()) {
5666 unsigned Size = Info.Ctx.getTypeSize(E->getType());
5667 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
5668 Result.Base = (Expr*)nullptr;
5669 Result.InvalidBase = false;
5670 Result.Offset = CharUnits::fromQuantity(N);
5671 Result.CallIndex = 0;
5672 Result.Designator.setInvalid();
5673 Result.IsNullPtr = false;
5676 // Cast is of an lvalue, no need to change value.
5677 Result.setFrom(Info.Ctx, Value);
5681 case CK_ArrayToPointerDecay:
5682 if (SubExpr->isGLValue()) {
5683 if (!evaluateLValue(SubExpr, Result))
5686 Result.set(SubExpr, Info.CurrentCall->Index);
5687 if (!EvaluateInPlace(Info.CurrentCall->createTemporary(SubExpr, false),
5688 Info, Result, SubExpr))
5691 // The result is a pointer to the first element of the array.
5692 if (const ConstantArrayType *CAT
5693 = Info.Ctx.getAsConstantArrayType(SubExpr->getType()))
5694 Result.addArray(Info, E, CAT);
5696 Result.Designator.setInvalid();
5699 case CK_FunctionToPointerDecay:
5700 return evaluateLValue(SubExpr, Result);
5702 case CK_LValueToRValue: {
5704 if (!evaluateLValue(E->getSubExpr(), LVal))
5708 // Note, we use the subexpression's type in order to retain cv-qualifiers.
5709 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
5711 return InvalidBaseOK &&
5712 evaluateLValueAsAllocSize(Info, LVal.Base, Result);
5713 return Success(RVal, E);
5717 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5720 static CharUnits GetAlignOfType(EvalInfo &Info, QualType T) {
5721 // C++ [expr.alignof]p3:
5722 // When alignof is applied to a reference type, the result is the
5723 // alignment of the referenced type.
5724 if (const ReferenceType *Ref = T->getAs<ReferenceType>())
5725 T = Ref->getPointeeType();
5727 // __alignof is defined to return the preferred alignment.
5728 if (T.getQualifiers().hasUnaligned())
5729 return CharUnits::One();
5730 return Info.Ctx.toCharUnitsFromBits(
5731 Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
5734 static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E) {
5735 E = E->IgnoreParens();
5737 // The kinds of expressions that we have special-case logic here for
5738 // should be kept up to date with the special checks for those
5739 // expressions in Sema.
5741 // alignof decl is always accepted, even if it doesn't make sense: we default
5742 // to 1 in those cases.
5743 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
5744 return Info.Ctx.getDeclAlign(DRE->getDecl(),
5745 /*RefAsPointee*/true);
5747 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
5748 return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
5749 /*RefAsPointee*/true);
5751 return GetAlignOfType(Info, E->getType());
5754 // To be clear: this happily visits unsupported builtins. Better name welcomed.
5755 bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
5756 if (ExprEvaluatorBaseTy::VisitCallExpr(E))
5759 if (!(InvalidBaseOK && getAllocSizeAttr(E)))
5762 Result.setInvalid(E);
5763 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
5764 Result.addUnsizedArray(Info, PointeeTy);
5768 bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
5769 if (IsStringLiteralCall(E))
5772 if (unsigned BuiltinOp = E->getBuiltinCallee())
5773 return VisitBuiltinCallExpr(E, BuiltinOp);
5775 return visitNonBuiltinCallExpr(E);
5778 bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
5779 unsigned BuiltinOp) {
5780 switch (BuiltinOp) {
5781 case Builtin::BI__builtin_addressof:
5782 return evaluateLValue(E->getArg(0), Result);
5783 case Builtin::BI__builtin_assume_aligned: {
5784 // We need to be very careful here because: if the pointer does not have the
5785 // asserted alignment, then the behavior is undefined, and undefined
5786 // behavior is non-constant.
5787 if (!evaluatePointer(E->getArg(0), Result))
5790 LValue OffsetResult(Result);
5792 if (!EvaluateInteger(E->getArg(1), Alignment, Info))
5794 CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue());
5796 if (E->getNumArgs() > 2) {
5798 if (!EvaluateInteger(E->getArg(2), Offset, Info))
5801 int64_t AdditionalOffset = -Offset.getZExtValue();
5802 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
5805 // If there is a base object, then it must have the correct alignment.
5806 if (OffsetResult.Base) {
5807 CharUnits BaseAlignment;
5808 if (const ValueDecl *VD =
5809 OffsetResult.Base.dyn_cast<const ValueDecl*>()) {
5810 BaseAlignment = Info.Ctx.getDeclAlign(VD);
5813 GetAlignOfExpr(Info, OffsetResult.Base.get<const Expr*>());
5816 if (BaseAlignment < Align) {
5817 Result.Designator.setInvalid();
5818 // FIXME: Add support to Diagnostic for long / long long.
5819 CCEDiag(E->getArg(0),
5820 diag::note_constexpr_baa_insufficient_alignment) << 0
5821 << (unsigned)BaseAlignment.getQuantity()
5822 << (unsigned)Align.getQuantity();
5827 // The offset must also have the correct alignment.
5828 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
5829 Result.Designator.setInvalid();
5832 ? CCEDiag(E->getArg(0),
5833 diag::note_constexpr_baa_insufficient_alignment) << 1
5834 : CCEDiag(E->getArg(0),
5835 diag::note_constexpr_baa_value_insufficient_alignment))
5836 << (int)OffsetResult.Offset.getQuantity()
5837 << (unsigned)Align.getQuantity();
5844 case Builtin::BIstrchr:
5845 case Builtin::BIwcschr:
5846 case Builtin::BImemchr:
5847 case Builtin::BIwmemchr:
5848 if (Info.getLangOpts().CPlusPlus11)
5849 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
5850 << /*isConstexpr*/0 << /*isConstructor*/0
5851 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
5853 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
5855 case Builtin::BI__builtin_strchr:
5856 case Builtin::BI__builtin_wcschr:
5857 case Builtin::BI__builtin_memchr:
5858 case Builtin::BI__builtin_char_memchr:
5859 case Builtin::BI__builtin_wmemchr: {
5860 if (!Visit(E->getArg(0)))
5863 if (!EvaluateInteger(E->getArg(1), Desired, Info))
5865 uint64_t MaxLength = uint64_t(-1);
5866 if (BuiltinOp != Builtin::BIstrchr &&
5867 BuiltinOp != Builtin::BIwcschr &&
5868 BuiltinOp != Builtin::BI__builtin_strchr &&
5869 BuiltinOp != Builtin::BI__builtin_wcschr) {
5871 if (!EvaluateInteger(E->getArg(2), N, Info))
5873 MaxLength = N.getExtValue();
5876 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
5878 // Figure out what value we're actually looking for (after converting to
5879 // the corresponding unsigned type if necessary).
5880 uint64_t DesiredVal;
5881 bool StopAtNull = false;
5882 switch (BuiltinOp) {
5883 case Builtin::BIstrchr:
5884 case Builtin::BI__builtin_strchr:
5885 // strchr compares directly to the passed integer, and therefore
5886 // always fails if given an int that is not a char.
5887 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy,
5888 E->getArg(1)->getType(),
5891 return ZeroInitialization(E);
5894 case Builtin::BImemchr:
5895 case Builtin::BI__builtin_memchr:
5896 case Builtin::BI__builtin_char_memchr:
5897 // memchr compares by converting both sides to unsigned char. That's also
5898 // correct for strchr if we get this far (to cope with plain char being
5899 // unsigned in the strchr case).
5900 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue();
5903 case Builtin::BIwcschr:
5904 case Builtin::BI__builtin_wcschr:
5907 case Builtin::BIwmemchr:
5908 case Builtin::BI__builtin_wmemchr:
5909 // wcschr and wmemchr are given a wchar_t to look for. Just use it.
5910 DesiredVal = Desired.getZExtValue();
5914 for (; MaxLength; --MaxLength) {
5916 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
5919 if (Char.getInt().getZExtValue() == DesiredVal)
5921 if (StopAtNull && !Char.getInt())
5923 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
5926 // Not found: return nullptr.
5927 return ZeroInitialization(E);
5931 return visitNonBuiltinCallExpr(E);
5935 //===----------------------------------------------------------------------===//
5936 // Member Pointer Evaluation
5937 //===----------------------------------------------------------------------===//
5940 class MemberPointerExprEvaluator
5941 : public ExprEvaluatorBase<MemberPointerExprEvaluator> {
5944 bool Success(const ValueDecl *D) {
5945 Result = MemberPtr(D);
5950 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
5951 : ExprEvaluatorBaseTy(Info), Result(Result) {}
5953 bool Success(const APValue &V, const Expr *E) {
5957 bool ZeroInitialization(const Expr *E) {
5958 return Success((const ValueDecl*)nullptr);
5961 bool VisitCastExpr(const CastExpr *E);
5962 bool VisitUnaryAddrOf(const UnaryOperator *E);
5964 } // end anonymous namespace
5966 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
5968 assert(E->isRValue() && E->getType()->isMemberPointerType());
5969 return MemberPointerExprEvaluator(Info, Result).Visit(E);
5972 bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
5973 switch (E->getCastKind()) {
5975 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5977 case CK_NullToMemberPointer:
5978 VisitIgnoredValue(E->getSubExpr());
5979 return ZeroInitialization(E);
5981 case CK_BaseToDerivedMemberPointer: {
5982 if (!Visit(E->getSubExpr()))
5984 if (E->path_empty())
5986 // Base-to-derived member pointer casts store the path in derived-to-base
5987 // order, so iterate backwards. The CXXBaseSpecifier also provides us with
5988 // the wrong end of the derived->base arc, so stagger the path by one class.
5989 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
5990 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
5991 PathI != PathE; ++PathI) {
5992 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
5993 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
5994 if (!Result.castToDerived(Derived))
5997 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
5998 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
6003 case CK_DerivedToBaseMemberPointer:
6004 if (!Visit(E->getSubExpr()))
6006 for (CastExpr::path_const_iterator PathI = E->path_begin(),
6007 PathE = E->path_end(); PathI != PathE; ++PathI) {
6008 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
6009 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
6010 if (!Result.castToBase(Base))
6017 bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
6018 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
6019 // member can be formed.
6020 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
6023 //===----------------------------------------------------------------------===//
6024 // Record Evaluation
6025 //===----------------------------------------------------------------------===//
6028 class RecordExprEvaluator
6029 : public ExprEvaluatorBase<RecordExprEvaluator> {
6034 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
6035 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
6037 bool Success(const APValue &V, const Expr *E) {
6041 bool ZeroInitialization(const Expr *E) {
6042 return ZeroInitialization(E, E->getType());
6044 bool ZeroInitialization(const Expr *E, QualType T);
6046 bool VisitCallExpr(const CallExpr *E) {
6047 return handleCallExpr(E, Result, &This);
6049 bool VisitCastExpr(const CastExpr *E);
6050 bool VisitInitListExpr(const InitListExpr *E);
6051 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
6052 return VisitCXXConstructExpr(E, E->getType());
6054 bool VisitLambdaExpr(const LambdaExpr *E);
6055 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
6056 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
6057 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
6061 /// Perform zero-initialization on an object of non-union class type.
6062 /// C++11 [dcl.init]p5:
6063 /// To zero-initialize an object or reference of type T means:
6065 /// -- if T is a (possibly cv-qualified) non-union class type,
6066 /// each non-static data member and each base-class subobject is
6067 /// zero-initialized
6068 static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
6069 const RecordDecl *RD,
6070 const LValue &This, APValue &Result) {
6071 assert(!RD->isUnion() && "Expected non-union class type");
6072 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
6073 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
6074 std::distance(RD->field_begin(), RD->field_end()));
6076 if (RD->isInvalidDecl()) return false;
6077 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6081 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
6082 End = CD->bases_end(); I != End; ++I, ++Index) {
6083 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
6084 LValue Subobject = This;
6085 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout))
6087 if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
6088 Result.getStructBase(Index)))
6093 for (const auto *I : RD->fields()) {
6094 // -- if T is a reference type, no initialization is performed.
6095 if (I->getType()->isReferenceType())
6098 LValue Subobject = This;
6099 if (!HandleLValueMember(Info, E, Subobject, I, &Layout))
6102 ImplicitValueInitExpr VIE(I->getType());
6103 if (!EvaluateInPlace(
6104 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE))
6111 bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
6112 const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
6113 if (RD->isInvalidDecl()) return false;
6114 if (RD->isUnion()) {
6115 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
6116 // object's first non-static named data member is zero-initialized
6117 RecordDecl::field_iterator I = RD->field_begin();
6118 if (I == RD->field_end()) {
6119 Result = APValue((const FieldDecl*)nullptr);
6123 LValue Subobject = This;
6124 if (!HandleLValueMember(Info, E, Subobject, *I))
6126 Result = APValue(*I);
6127 ImplicitValueInitExpr VIE(I->getType());
6128 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
6131 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
6132 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
6136 return HandleClassZeroInitialization(Info, E, RD, This, Result);
6139 bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
6140 switch (E->getCastKind()) {
6142 return ExprEvaluatorBaseTy::VisitCastExpr(E);
6144 case CK_ConstructorConversion:
6145 return Visit(E->getSubExpr());
6147 case CK_DerivedToBase:
6148 case CK_UncheckedDerivedToBase: {
6149 APValue DerivedObject;
6150 if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
6152 if (!DerivedObject.isStruct())
6153 return Error(E->getSubExpr());
6155 // Derived-to-base rvalue conversion: just slice off the derived part.
6156 APValue *Value = &DerivedObject;
6157 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
6158 for (CastExpr::path_const_iterator PathI = E->path_begin(),
6159 PathE = E->path_end(); PathI != PathE; ++PathI) {
6160 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base");
6161 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
6162 Value = &Value->getStructBase(getBaseIndex(RD, Base));
6171 bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6172 if (E->isTransparent())
6173 return Visit(E->getInit(0));
6175 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
6176 if (RD->isInvalidDecl()) return false;
6177 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6179 if (RD->isUnion()) {
6180 const FieldDecl *Field = E->getInitializedFieldInUnion();
6181 Result = APValue(Field);
6185 // If the initializer list for a union does not contain any elements, the
6186 // first element of the union is value-initialized.
6187 // FIXME: The element should be initialized from an initializer list.
6188 // Is this difference ever observable for initializer lists which
6190 ImplicitValueInitExpr VIE(Field->getType());
6191 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;
6193 LValue Subobject = This;
6194 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout))
6197 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
6198 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
6199 isa<CXXDefaultInitExpr>(InitExpr));
6201 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr);
6204 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
6205 if (Result.isUninit())
6206 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
6207 std::distance(RD->field_begin(), RD->field_end()));
6208 unsigned ElementNo = 0;
6209 bool Success = true;
6211 // Initialize base classes.
6213 for (const auto &Base : CXXRD->bases()) {
6214 assert(ElementNo < E->getNumInits() && "missing init for base class");
6215 const Expr *Init = E->getInit(ElementNo);
6217 LValue Subobject = This;
6218 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base))
6221 APValue &FieldVal = Result.getStructBase(ElementNo);
6222 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) {
6223 if (!Info.noteFailure())
6231 // Initialize members.
6232 for (const auto *Field : RD->fields()) {
6233 // Anonymous bit-fields are not considered members of the class for
6234 // purposes of aggregate initialization.
6235 if (Field->isUnnamedBitfield())
6238 LValue Subobject = This;
6240 bool HaveInit = ElementNo < E->getNumInits();
6242 // FIXME: Diagnostics here should point to the end of the initializer
6243 // list, not the start.
6244 if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E,
6245 Subobject, Field, &Layout))
6248 // Perform an implicit value-initialization for members beyond the end of
6249 // the initializer list.
6250 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
6251 const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE;
6252 if (Init->isValueDependent()) {
6257 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
6258 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
6259 isa<CXXDefaultInitExpr>(Init));
6261 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
6262 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) ||
6263 (Field->isBitField() && !truncateBitfieldValue(Info, Init,
6264 FieldVal, Field))) {
6265 if (!Info.noteFailure())
6274 bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
6276 // Note that E's type is not necessarily the type of our class here; we might
6277 // be initializing an array element instead.
6278 const CXXConstructorDecl *FD = E->getConstructor();
6279 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
6281 bool ZeroInit = E->requiresZeroInitialization();
6282 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
6283 // If we've already performed zero-initialization, we're already done.
6284 if (!Result.isUninit())
6287 // We can get here in two different ways:
6288 // 1) We're performing value-initialization, and should zero-initialize
6290 // 2) We're performing default-initialization of an object with a trivial
6291 // constexpr default constructor, in which case we should start the
6292 // lifetimes of all the base subobjects (there can be no data member
6293 // subobjects in this case) per [basic.life]p1.
6294 // Either way, ZeroInitialization is appropriate.
6295 return ZeroInitialization(E, T);
6298 const FunctionDecl *Definition = nullptr;
6299 auto Body = FD->getBody(Definition);
6301 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
6304 // Avoid materializing a temporary for an elidable copy/move constructor.
6305 if (E->isElidable() && !ZeroInit)
6306 if (const MaterializeTemporaryExpr *ME
6307 = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0)))
6308 return Visit(ME->GetTemporaryExpr());
6310 if (ZeroInit && !ZeroInitialization(E, T))
6313 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
6314 return HandleConstructorCall(E, This, Args,
6315 cast<CXXConstructorDecl>(Definition), Info,
6319 bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
6320 const CXXInheritedCtorInitExpr *E) {
6321 if (!Info.CurrentCall) {
6322 assert(Info.checkingPotentialConstantExpression());
6326 const CXXConstructorDecl *FD = E->getConstructor();
6327 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
6330 const FunctionDecl *Definition = nullptr;
6331 auto Body = FD->getBody(Definition);
6333 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
6336 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
6337 cast<CXXConstructorDecl>(Definition), Info,
6341 bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
6342 const CXXStdInitializerListExpr *E) {
6343 const ConstantArrayType *ArrayType =
6344 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
6347 if (!EvaluateLValue(E->getSubExpr(), Array, Info))
6350 // Get a pointer to the first element of the array.
6351 Array.addArray(Info, E, ArrayType);
6353 // FIXME: Perform the checks on the field types in SemaInit.
6354 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
6355 RecordDecl::field_iterator Field = Record->field_begin();
6356 if (Field == Record->field_end())
6360 if (!Field->getType()->isPointerType() ||
6361 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
6362 ArrayType->getElementType()))
6365 // FIXME: What if the initializer_list type has base classes, etc?
6366 Result = APValue(APValue::UninitStruct(), 0, 2);
6367 Array.moveInto(Result.getStructField(0));
6369 if (++Field == Record->field_end())
6372 if (Field->getType()->isPointerType() &&
6373 Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
6374 ArrayType->getElementType())) {
6376 if (!HandleLValueArrayAdjustment(Info, E, Array,
6377 ArrayType->getElementType(),
6378 ArrayType->getSize().getZExtValue()))
6380 Array.moveInto(Result.getStructField(1));
6381 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
6383 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize()));
6387 if (++Field != Record->field_end())
6393 bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
6394 const CXXRecordDecl *ClosureClass = E->getLambdaClass();
6395 if (ClosureClass->isInvalidDecl()) return false;
6397 if (Info.checkingPotentialConstantExpression()) return true;
6399 const size_t NumFields =
6400 std::distance(ClosureClass->field_begin(), ClosureClass->field_end());
6402 assert(NumFields == (size_t)std::distance(E->capture_init_begin(),
6403 E->capture_init_end()) &&
6404 "The number of lambda capture initializers should equal the number of "
6405 "fields within the closure type");
6407 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields);
6408 // Iterate through all the lambda's closure object's fields and initialize
6410 auto *CaptureInitIt = E->capture_init_begin();
6411 const LambdaCapture *CaptureIt = ClosureClass->captures_begin();
6412 bool Success = true;
6413 for (const auto *Field : ClosureClass->fields()) {
6414 assert(CaptureInitIt != E->capture_init_end());
6415 // Get the initializer for this field
6416 Expr *const CurFieldInit = *CaptureInitIt++;
6418 // If there is no initializer, either this is a VLA or an error has
6423 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
6424 if (!EvaluateInPlace(FieldVal, Info, This, CurFieldInit)) {
6425 if (!Info.keepEvaluatingAfterFailure())
6434 static bool EvaluateRecord(const Expr *E, const LValue &This,
6435 APValue &Result, EvalInfo &Info) {
6436 assert(E->isRValue() && E->getType()->isRecordType() &&
6437 "can't evaluate expression as a record rvalue");
6438 return RecordExprEvaluator(Info, This, Result).Visit(E);
6441 //===----------------------------------------------------------------------===//
6442 // Temporary Evaluation
6444 // Temporaries are represented in the AST as rvalues, but generally behave like
6445 // lvalues. The full-object of which the temporary is a subobject is implicitly
6446 // materialized so that a reference can bind to it.
6447 //===----------------------------------------------------------------------===//
6449 class TemporaryExprEvaluator
6450 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
6452 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
6453 LValueExprEvaluatorBaseTy(Info, Result, false) {}
6455 /// Visit an expression which constructs the value of this temporary.
6456 bool VisitConstructExpr(const Expr *E) {
6457 Result.set(E, Info.CurrentCall->Index);
6458 return EvaluateInPlace(Info.CurrentCall->createTemporary(E, false),
6462 bool VisitCastExpr(const CastExpr *E) {
6463 switch (E->getCastKind()) {
6465 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
6467 case CK_ConstructorConversion:
6468 return VisitConstructExpr(E->getSubExpr());
6471 bool VisitInitListExpr(const InitListExpr *E) {
6472 return VisitConstructExpr(E);
6474 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
6475 return VisitConstructExpr(E);
6477 bool VisitCallExpr(const CallExpr *E) {
6478 return VisitConstructExpr(E);
6480 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
6481 return VisitConstructExpr(E);
6483 bool VisitLambdaExpr(const LambdaExpr *E) {
6484 return VisitConstructExpr(E);
6487 } // end anonymous namespace
6489 /// Evaluate an expression of record type as a temporary.
6490 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
6491 assert(E->isRValue() && E->getType()->isRecordType());
6492 return TemporaryExprEvaluator(Info, Result).Visit(E);
6495 //===----------------------------------------------------------------------===//
6496 // Vector Evaluation
6497 //===----------------------------------------------------------------------===//
6500 class VectorExprEvaluator
6501 : public ExprEvaluatorBase<VectorExprEvaluator> {
6505 VectorExprEvaluator(EvalInfo &info, APValue &Result)
6506 : ExprEvaluatorBaseTy(info), Result(Result) {}
6508 bool Success(ArrayRef<APValue> V, const Expr *E) {
6509 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements());
6510 // FIXME: remove this APValue copy.
6511 Result = APValue(V.data(), V.size());
6514 bool Success(const APValue &V, const Expr *E) {
6515 assert(V.isVector());
6519 bool ZeroInitialization(const Expr *E);
6521 bool VisitUnaryReal(const UnaryOperator *E)
6522 { return Visit(E->getSubExpr()); }
6523 bool VisitCastExpr(const CastExpr* E);
6524 bool VisitInitListExpr(const InitListExpr *E);
6525 bool VisitUnaryImag(const UnaryOperator *E);
6526 // FIXME: Missing: unary -, unary ~, binary add/sub/mul/div,
6527 // binary comparisons, binary and/or/xor,
6528 // shufflevector, ExtVectorElementExpr
6530 } // end anonymous namespace
6532 static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
6533 assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue");
6534 return VectorExprEvaluator(Info, Result).Visit(E);
6537 bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
6538 const VectorType *VTy = E->getType()->castAs<VectorType>();
6539 unsigned NElts = VTy->getNumElements();
6541 const Expr *SE = E->getSubExpr();
6542 QualType SETy = SE->getType();
6544 switch (E->getCastKind()) {
6545 case CK_VectorSplat: {
6546 APValue Val = APValue();
6547 if (SETy->isIntegerType()) {
6549 if (!EvaluateInteger(SE, IntResult, Info))
6551 Val = APValue(std::move(IntResult));
6552 } else if (SETy->isRealFloatingType()) {
6553 APFloat FloatResult(0.0);
6554 if (!EvaluateFloat(SE, FloatResult, Info))
6556 Val = APValue(std::move(FloatResult));
6561 // Splat and create vector APValue.
6562 SmallVector<APValue, 4> Elts(NElts, Val);
6563 return Success(Elts, E);
6566 // Evaluate the operand into an APInt we can extract from.
6567 llvm::APInt SValInt;
6568 if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
6570 // Extract the elements
6571 QualType EltTy = VTy->getElementType();
6572 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
6573 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
6574 SmallVector<APValue, 4> Elts;
6575 if (EltTy->isRealFloatingType()) {
6576 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
6577 unsigned FloatEltSize = EltSize;
6578 if (&Sem == &APFloat::x87DoubleExtended())
6580 for (unsigned i = 0; i < NElts; i++) {
6583 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
6585 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
6586 Elts.push_back(APValue(APFloat(Sem, Elt)));
6588 } else if (EltTy->isIntegerType()) {
6589 for (unsigned i = 0; i < NElts; i++) {
6592 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
6594 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
6595 Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType())));
6600 return Success(Elts, E);
6603 return ExprEvaluatorBaseTy::VisitCastExpr(E);
6608 VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6609 const VectorType *VT = E->getType()->castAs<VectorType>();
6610 unsigned NumInits = E->getNumInits();
6611 unsigned NumElements = VT->getNumElements();
6613 QualType EltTy = VT->getElementType();
6614 SmallVector<APValue, 4> Elements;
6616 // The number of initializers can be less than the number of
6617 // vector elements. For OpenCL, this can be due to nested vector
6618 // initialization. For GCC compatibility, missing trailing elements
6619 // should be initialized with zeroes.
6620 unsigned CountInits = 0, CountElts = 0;
6621 while (CountElts < NumElements) {
6622 // Handle nested vector initialization.
6623 if (CountInits < NumInits
6624 && E->getInit(CountInits)->getType()->isVectorType()) {
6626 if (!EvaluateVector(E->getInit(CountInits), v, Info))
6628 unsigned vlen = v.getVectorLength();
6629 for (unsigned j = 0; j < vlen; j++)
6630 Elements.push_back(v.getVectorElt(j));
6632 } else if (EltTy->isIntegerType()) {
6633 llvm::APSInt sInt(32);
6634 if (CountInits < NumInits) {
6635 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
6637 } else // trailing integer zero.
6638 sInt = Info.Ctx.MakeIntValue(0, EltTy);
6639 Elements.push_back(APValue(sInt));
6642 llvm::APFloat f(0.0);
6643 if (CountInits < NumInits) {
6644 if (!EvaluateFloat(E->getInit(CountInits), f, Info))
6646 } else // trailing float zero.
6647 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
6648 Elements.push_back(APValue(f));
6653 return Success(Elements, E);
6657 VectorExprEvaluator::ZeroInitialization(const Expr *E) {
6658 const VectorType *VT = E->getType()->getAs<VectorType>();
6659 QualType EltTy = VT->getElementType();
6660 APValue ZeroElement;
6661 if (EltTy->isIntegerType())
6662 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
6665 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
6667 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
6668 return Success(Elements, E);
6671 bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
6672 VisitIgnoredValue(E->getSubExpr());
6673 return ZeroInitialization(E);
6676 //===----------------------------------------------------------------------===//
6678 //===----------------------------------------------------------------------===//
6681 class ArrayExprEvaluator
6682 : public ExprEvaluatorBase<ArrayExprEvaluator> {
6687 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
6688 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
6690 bool Success(const APValue &V, const Expr *E) {
6691 assert((V.isArray() || V.isLValue()) &&
6692 "expected array or string literal");
6697 bool ZeroInitialization(const Expr *E) {
6698 const ConstantArrayType *CAT =
6699 Info.Ctx.getAsConstantArrayType(E->getType());
6703 Result = APValue(APValue::UninitArray(), 0,
6704 CAT->getSize().getZExtValue());
6705 if (!Result.hasArrayFiller()) return true;
6707 // Zero-initialize all elements.
6708 LValue Subobject = This;
6709 Subobject.addArray(Info, E, CAT);
6710 ImplicitValueInitExpr VIE(CAT->getElementType());
6711 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
6714 bool VisitCallExpr(const CallExpr *E) {
6715 return handleCallExpr(E, Result, &This);
6717 bool VisitInitListExpr(const InitListExpr *E);
6718 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
6719 bool VisitCXXConstructExpr(const CXXConstructExpr *E);
6720 bool VisitCXXConstructExpr(const CXXConstructExpr *E,
6721 const LValue &Subobject,
6722 APValue *Value, QualType Type);
6724 } // end anonymous namespace
6726 static bool EvaluateArray(const Expr *E, const LValue &This,
6727 APValue &Result, EvalInfo &Info) {
6728 assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue");
6729 return ArrayExprEvaluator(Info, This, Result).Visit(E);
6732 bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6733 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType());
6737 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
6738 // an appropriately-typed string literal enclosed in braces.
6739 if (E->isStringLiteralInit()) {
6741 if (!EvaluateLValue(E->getInit(0), LV, Info))
6745 return Success(Val, E);
6748 bool Success = true;
6750 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&
6751 "zero-initialized array shouldn't have any initialized elts");
6753 if (Result.isArray() && Result.hasArrayFiller())
6754 Filler = Result.getArrayFiller();
6756 unsigned NumEltsToInit = E->getNumInits();
6757 unsigned NumElts = CAT->getSize().getZExtValue();
6758 const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr;
6760 // If the initializer might depend on the array index, run it for each
6761 // array element. For now, just whitelist non-class value-initialization.
6762 if (NumEltsToInit != NumElts && !isa<ImplicitValueInitExpr>(FillerExpr))
6763 NumEltsToInit = NumElts;
6765 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
6767 // If the array was previously zero-initialized, preserve the
6768 // zero-initialized values.
6769 if (!Filler.isUninit()) {
6770 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
6771 Result.getArrayInitializedElt(I) = Filler;
6772 if (Result.hasArrayFiller())
6773 Result.getArrayFiller() = Filler;
6776 LValue Subobject = This;
6777 Subobject.addArray(Info, E, CAT);
6778 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
6780 Index < E->getNumInits() ? E->getInit(Index) : FillerExpr;
6781 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
6782 Info, Subobject, Init) ||
6783 !HandleLValueArrayAdjustment(Info, Init, Subobject,
6784 CAT->getElementType(), 1)) {
6785 if (!Info.noteFailure())
6791 if (!Result.hasArrayFiller())
6794 // If we get here, we have a trivial filler, which we can just evaluate
6795 // once and splat over the rest of the array elements.
6796 assert(FillerExpr && "no array filler for incomplete init list");
6797 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject,
6798 FillerExpr) && Success;
6801 bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
6802 if (E->getCommonExpr() &&
6803 !Evaluate(Info.CurrentCall->createTemporary(E->getCommonExpr(), false),
6804 Info, E->getCommonExpr()->getSourceExpr()))
6807 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());
6809 uint64_t Elements = CAT->getSize().getZExtValue();
6810 Result = APValue(APValue::UninitArray(), Elements, Elements);
6812 LValue Subobject = This;
6813 Subobject.addArray(Info, E, CAT);
6815 bool Success = true;
6816 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
6817 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
6818 Info, Subobject, E->getSubExpr()) ||
6819 !HandleLValueArrayAdjustment(Info, E, Subobject,
6820 CAT->getElementType(), 1)) {
6821 if (!Info.noteFailure())
6830 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
6831 return VisitCXXConstructExpr(E, This, &Result, E->getType());
6834 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
6835 const LValue &Subobject,
6838 bool HadZeroInit = !Value->isUninit();
6840 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
6841 unsigned N = CAT->getSize().getZExtValue();
6843 // Preserve the array filler if we had prior zero-initialization.
6845 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
6848 *Value = APValue(APValue::UninitArray(), N, N);
6851 for (unsigned I = 0; I != N; ++I)
6852 Value->getArrayInitializedElt(I) = Filler;
6854 // Initialize the elements.
6855 LValue ArrayElt = Subobject;
6856 ArrayElt.addArray(Info, E, CAT);
6857 for (unsigned I = 0; I != N; ++I)
6858 if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I),
6859 CAT->getElementType()) ||
6860 !HandleLValueArrayAdjustment(Info, E, ArrayElt,
6861 CAT->getElementType(), 1))
6867 if (!Type->isRecordType())
6870 return RecordExprEvaluator(Info, Subobject, *Value)
6871 .VisitCXXConstructExpr(E, Type);
6874 //===----------------------------------------------------------------------===//
6875 // Integer Evaluation
6877 // As a GNU extension, we support casting pointers to sufficiently-wide integer
6878 // types and back in constant folding. Integer values are thus represented
6879 // either as an integer-valued APValue, or as an lvalue-valued APValue.
6880 //===----------------------------------------------------------------------===//
6883 class IntExprEvaluator
6884 : public ExprEvaluatorBase<IntExprEvaluator> {
6887 IntExprEvaluator(EvalInfo &info, APValue &result)
6888 : ExprEvaluatorBaseTy(info), Result(result) {}
6890 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
6891 assert(E->getType()->isIntegralOrEnumerationType() &&
6892 "Invalid evaluation result.");
6893 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
6894 "Invalid evaluation result.");
6895 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
6896 "Invalid evaluation result.");
6897 Result = APValue(SI);
6900 bool Success(const llvm::APSInt &SI, const Expr *E) {
6901 return Success(SI, E, Result);
6904 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
6905 assert(E->getType()->isIntegralOrEnumerationType() &&
6906 "Invalid evaluation result.");
6907 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
6908 "Invalid evaluation result.");
6909 Result = APValue(APSInt(I));
6910 Result.getInt().setIsUnsigned(
6911 E->getType()->isUnsignedIntegerOrEnumerationType());
6914 bool Success(const llvm::APInt &I, const Expr *E) {
6915 return Success(I, E, Result);
6918 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
6919 assert(E->getType()->isIntegralOrEnumerationType() &&
6920 "Invalid evaluation result.");
6921 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
6924 bool Success(uint64_t Value, const Expr *E) {
6925 return Success(Value, E, Result);
6928 bool Success(CharUnits Size, const Expr *E) {
6929 return Success(Size.getQuantity(), E);
6932 bool Success(const APValue &V, const Expr *E) {
6933 if (V.isLValue() || V.isAddrLabelDiff()) {
6937 return Success(V.getInt(), E);
6940 bool ZeroInitialization(const Expr *E) { return Success(0, E); }
6942 //===--------------------------------------------------------------------===//
6944 //===--------------------------------------------------------------------===//
6946 bool VisitIntegerLiteral(const IntegerLiteral *E) {
6947 return Success(E->getValue(), E);
6949 bool VisitCharacterLiteral(const CharacterLiteral *E) {
6950 return Success(E->getValue(), E);
6953 bool CheckReferencedDecl(const Expr *E, const Decl *D);
6954 bool VisitDeclRefExpr(const DeclRefExpr *E) {
6955 if (CheckReferencedDecl(E, E->getDecl()))
6958 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
6960 bool VisitMemberExpr(const MemberExpr *E) {
6961 if (CheckReferencedDecl(E, E->getMemberDecl())) {
6962 VisitIgnoredBaseExpression(E->getBase());
6966 return ExprEvaluatorBaseTy::VisitMemberExpr(E);
6969 bool VisitCallExpr(const CallExpr *E);
6970 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
6971 bool VisitBinaryOperator(const BinaryOperator *E);
6972 bool VisitOffsetOfExpr(const OffsetOfExpr *E);
6973 bool VisitUnaryOperator(const UnaryOperator *E);
6975 bool VisitCastExpr(const CastExpr* E);
6976 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
6978 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
6979 return Success(E->getValue(), E);
6982 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
6983 return Success(E->getValue(), E);
6986 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
6987 if (Info.ArrayInitIndex == uint64_t(-1)) {
6988 // We were asked to evaluate this subexpression independent of the
6989 // enclosing ArrayInitLoopExpr. We can't do that.
6993 return Success(Info.ArrayInitIndex, E);
6996 // Note, GNU defines __null as an integer, not a pointer.
6997 bool VisitGNUNullExpr(const GNUNullExpr *E) {
6998 return ZeroInitialization(E);
7001 bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
7002 return Success(E->getValue(), E);
7005 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
7006 return Success(E->getValue(), E);
7009 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
7010 return Success(E->getValue(), E);
7013 bool VisitUnaryReal(const UnaryOperator *E);
7014 bool VisitUnaryImag(const UnaryOperator *E);
7016 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
7017 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
7019 // FIXME: Missing: array subscript of vector, member of vector
7021 } // end anonymous namespace
7023 /// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
7024 /// produce either the integer value or a pointer.
7026 /// GCC has a heinous extension which folds casts between pointer types and
7027 /// pointer-sized integral types. We support this by allowing the evaluation of
7028 /// an integer rvalue to produce a pointer (represented as an lvalue) instead.
7029 /// Some simple arithmetic on such values is supported (they are treated much
7031 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
7033 assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType());
7034 return IntExprEvaluator(Info, Result).Visit(E);
7037 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
7039 if (!EvaluateIntegerOrLValue(E, Val, Info))
7042 // FIXME: It would be better to produce the diagnostic for casting
7043 // a pointer to an integer.
7044 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
7047 Result = Val.getInt();
7051 /// Check whether the given declaration can be directly converted to an integral
7052 /// rvalue. If not, no diagnostic is produced; there are other things we can
7054 bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
7055 // Enums are integer constant exprs.
7056 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
7057 // Check for signedness/width mismatches between E type and ECD value.
7058 bool SameSign = (ECD->getInitVal().isSigned()
7059 == E->getType()->isSignedIntegerOrEnumerationType());
7060 bool SameWidth = (ECD->getInitVal().getBitWidth()
7061 == Info.Ctx.getIntWidth(E->getType()));
7062 if (SameSign && SameWidth)
7063 return Success(ECD->getInitVal(), E);
7065 // Get rid of mismatch (otherwise Success assertions will fail)
7066 // by computing a new value matching the type of E.
7067 llvm::APSInt Val = ECD->getInitVal();
7069 Val.setIsSigned(!ECD->getInitVal().isSigned());
7071 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
7072 return Success(Val, E);
7078 /// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
7080 static int EvaluateBuiltinClassifyType(const CallExpr *E,
7081 const LangOptions &LangOpts) {
7082 // The following enum mimics the values returned by GCC.
7083 // FIXME: Does GCC differ between lvalue and rvalue references here?
7084 enum gcc_type_class {
7086 void_type_class, integer_type_class, char_type_class,
7087 enumeral_type_class, boolean_type_class,
7088 pointer_type_class, reference_type_class, offset_type_class,
7089 real_type_class, complex_type_class,
7090 function_type_class, method_type_class,
7091 record_type_class, union_type_class,
7092 array_type_class, string_type_class,
7096 // If no argument was supplied, default to "no_type_class". This isn't
7097 // ideal, however it is what gcc does.
7098 if (E->getNumArgs() == 0)
7099 return no_type_class;
7101 QualType CanTy = E->getArg(0)->getType().getCanonicalType();
7102 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy);
7104 switch (CanTy->getTypeClass()) {
7105 #define TYPE(ID, BASE)
7106 #define DEPENDENT_TYPE(ID, BASE) case Type::ID:
7107 #define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
7108 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
7109 #include "clang/AST/TypeNodes.def"
7110 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7113 switch (BT->getKind()) {
7114 #define BUILTIN_TYPE(ID, SINGLETON_ID)
7115 #define SIGNED_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: return integer_type_class;
7116 #define FLOATING_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: return real_type_class;
7117 #define PLACEHOLDER_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: break;
7118 #include "clang/AST/BuiltinTypes.def"
7119 case BuiltinType::Void:
7120 return void_type_class;
7122 case BuiltinType::Bool:
7123 return boolean_type_class;
7125 case BuiltinType::Char_U: // gcc doesn't appear to use char_type_class
7126 case BuiltinType::UChar:
7127 case BuiltinType::UShort:
7128 case BuiltinType::UInt:
7129 case BuiltinType::ULong:
7130 case BuiltinType::ULongLong:
7131 case BuiltinType::UInt128:
7132 return integer_type_class;
7134 case BuiltinType::NullPtr:
7135 return pointer_type_class;
7137 case BuiltinType::WChar_U:
7138 case BuiltinType::Char16:
7139 case BuiltinType::Char32:
7140 case BuiltinType::ObjCId:
7141 case BuiltinType::ObjCClass:
7142 case BuiltinType::ObjCSel:
7143 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
7144 case BuiltinType::Id:
7145 #include "clang/Basic/OpenCLImageTypes.def"
7146 case BuiltinType::OCLSampler:
7147 case BuiltinType::OCLEvent:
7148 case BuiltinType::OCLClkEvent:
7149 case BuiltinType::OCLQueue:
7150 case BuiltinType::OCLReserveID:
7151 case BuiltinType::Dependent:
7152 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7156 return LangOpts.CPlusPlus ? enumeral_type_class : integer_type_class;
7160 return pointer_type_class;
7163 case Type::MemberPointer:
7164 if (CanTy->isMemberDataPointerType())
7165 return offset_type_class;
7167 // We expect member pointers to be either data or function pointers,
7169 assert(CanTy->isMemberFunctionPointerType());
7170 return method_type_class;
7174 return complex_type_class;
7176 case Type::FunctionNoProto:
7177 case Type::FunctionProto:
7178 return LangOpts.CPlusPlus ? function_type_class : pointer_type_class;
7181 if (const RecordType *RT = CanTy->getAs<RecordType>()) {
7182 switch (RT->getDecl()->getTagKind()) {
7183 case TagTypeKind::TTK_Struct:
7184 case TagTypeKind::TTK_Class:
7185 case TagTypeKind::TTK_Interface:
7186 return record_type_class;
7188 case TagTypeKind::TTK_Enum:
7189 return LangOpts.CPlusPlus ? enumeral_type_class : integer_type_class;
7191 case TagTypeKind::TTK_Union:
7192 return union_type_class;
7195 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7197 case Type::ConstantArray:
7198 case Type::VariableArray:
7199 case Type::IncompleteArray:
7200 return LangOpts.CPlusPlus ? array_type_class : pointer_type_class;
7202 case Type::BlockPointer:
7203 case Type::LValueReference:
7204 case Type::RValueReference:
7206 case Type::ExtVector:
7208 case Type::DeducedTemplateSpecialization:
7209 case Type::ObjCObject:
7210 case Type::ObjCInterface:
7211 case Type::ObjCObjectPointer:
7214 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7217 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7220 /// EvaluateBuiltinConstantPForLValue - Determine the result of
7221 /// __builtin_constant_p when applied to the given lvalue.
7223 /// An lvalue is only "constant" if it is a pointer or reference to the first
7224 /// character of a string literal.
7225 template<typename LValue>
7226 static bool EvaluateBuiltinConstantPForLValue(const LValue &LV) {
7227 const Expr *E = LV.getLValueBase().template dyn_cast<const Expr*>();
7228 return E && isa<StringLiteral>(E) && LV.getLValueOffset().isZero();
7231 /// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
7232 /// GCC as we can manage.
7233 static bool EvaluateBuiltinConstantP(ASTContext &Ctx, const Expr *Arg) {
7234 QualType ArgType = Arg->getType();
7236 // __builtin_constant_p always has one operand. The rules which gcc follows
7237 // are not precisely documented, but are as follows:
7239 // - If the operand is of integral, floating, complex or enumeration type,
7240 // and can be folded to a known value of that type, it returns 1.
7241 // - If the operand and can be folded to a pointer to the first character
7242 // of a string literal (or such a pointer cast to an integral type), it
7245 // Otherwise, it returns 0.
7247 // FIXME: GCC also intends to return 1 for literals of aggregate types, but
7248 // its support for this does not currently work.
7249 if (ArgType->isIntegralOrEnumerationType()) {
7250 Expr::EvalResult Result;
7251 if (!Arg->EvaluateAsRValue(Result, Ctx) || Result.HasSideEffects)
7254 APValue &V = Result.Val;
7255 if (V.getKind() == APValue::Int)
7257 if (V.getKind() == APValue::LValue)
7258 return EvaluateBuiltinConstantPForLValue(V);
7259 } else if (ArgType->isFloatingType() || ArgType->isAnyComplexType()) {
7260 return Arg->isEvaluatable(Ctx);
7261 } else if (ArgType->isPointerType() || Arg->isGLValue()) {
7263 Expr::EvalStatus Status;
7264 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
7265 if ((Arg->isGLValue() ? EvaluateLValue(Arg, LV, Info)
7266 : EvaluatePointer(Arg, LV, Info)) &&
7267 !Status.HasSideEffects)
7268 return EvaluateBuiltinConstantPForLValue(LV);
7271 // Anything else isn't considered to be sufficiently constant.
7275 /// Retrieves the "underlying object type" of the given expression,
7276 /// as used by __builtin_object_size.
7277 static QualType getObjectType(APValue::LValueBase B) {
7278 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
7279 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
7280 return VD->getType();
7281 } else if (const Expr *E = B.get<const Expr*>()) {
7282 if (isa<CompoundLiteralExpr>(E))
7283 return E->getType();
7289 /// A more selective version of E->IgnoreParenCasts for
7290 /// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
7291 /// to change the type of E.
7292 /// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
7294 /// Always returns an RValue with a pointer representation.
7295 static const Expr *ignorePointerCastsAndParens(const Expr *E) {
7296 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
7298 auto *NoParens = E->IgnoreParens();
7299 auto *Cast = dyn_cast<CastExpr>(NoParens);
7300 if (Cast == nullptr)
7303 // We only conservatively allow a few kinds of casts, because this code is
7304 // inherently a simple solution that seeks to support the common case.
7305 auto CastKind = Cast->getCastKind();
7306 if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
7307 CastKind != CK_AddressSpaceConversion)
7310 auto *SubExpr = Cast->getSubExpr();
7311 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isRValue())
7313 return ignorePointerCastsAndParens(SubExpr);
7316 /// Checks to see if the given LValue's Designator is at the end of the LValue's
7317 /// record layout. e.g.
7318 /// struct { struct { int a, b; } fst, snd; } obj;
7324 /// obj.snd.b // yes
7326 /// Please note: this function is specialized for how __builtin_object_size
7327 /// views "objects".
7329 /// If this encounters an invalid RecordDecl, it will always return true.
7330 static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
7331 assert(!LVal.Designator.Invalid);
7333 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
7334 const RecordDecl *Parent = FD->getParent();
7335 Invalid = Parent->isInvalidDecl();
7336 if (Invalid || Parent->isUnion())
7338 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent);
7339 return FD->getFieldIndex() + 1 == Layout.getFieldCount();
7342 auto &Base = LVal.getLValueBase();
7343 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) {
7344 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
7346 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
7348 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) {
7349 for (auto *FD : IFD->chain()) {
7351 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid))
7358 QualType BaseType = getType(Base);
7359 if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
7360 assert(isBaseAnAllocSizeCall(Base) &&
7361 "Unsized array in non-alloc_size call?");
7362 // If this is an alloc_size base, we should ignore the initial array index
7364 BaseType = BaseType->castAs<PointerType>()->getPointeeType();
7367 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
7368 const auto &Entry = LVal.Designator.Entries[I];
7369 if (BaseType->isArrayType()) {
7370 // Because __builtin_object_size treats arrays as objects, we can ignore
7371 // the index iff this is the last array in the Designator.
7374 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType));
7375 uint64_t Index = Entry.ArrayIndex;
7376 if (Index + 1 != CAT->getSize())
7378 BaseType = CAT->getElementType();
7379 } else if (BaseType->isAnyComplexType()) {
7380 const auto *CT = BaseType->castAs<ComplexType>();
7381 uint64_t Index = Entry.ArrayIndex;
7384 BaseType = CT->getElementType();
7385 } else if (auto *FD = getAsField(Entry)) {
7387 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
7389 BaseType = FD->getType();
7391 assert(getAsBaseClass(Entry) && "Expecting cast to a base class");
7398 /// Tests to see if the LValue has a user-specified designator (that isn't
7399 /// necessarily valid). Note that this always returns 'true' if the LValue has
7400 /// an unsized array as its first designator entry, because there's currently no
7401 /// way to tell if the user typed *foo or foo[0].
7402 static bool refersToCompleteObject(const LValue &LVal) {
7403 if (LVal.Designator.Invalid)
7406 if (!LVal.Designator.Entries.empty())
7407 return LVal.Designator.isMostDerivedAnUnsizedArray();
7409 if (!LVal.InvalidBase)
7412 // If `E` is a MemberExpr, then the first part of the designator is hiding in
7414 const auto *E = LVal.Base.dyn_cast<const Expr *>();
7415 return !E || !isa<MemberExpr>(E);
7418 /// Attempts to detect a user writing into a piece of memory that's impossible
7419 /// to figure out the size of by just using types.
7420 static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
7421 const SubobjectDesignator &Designator = LVal.Designator;
7423 // - Users can only write off of the end when we have an invalid base. Invalid
7424 // bases imply we don't know where the memory came from.
7425 // - We used to be a bit more aggressive here; we'd only be conservative if
7426 // the array at the end was flexible, or if it had 0 or 1 elements. This
7427 // broke some common standard library extensions (PR30346), but was
7428 // otherwise seemingly fine. It may be useful to reintroduce this behavior
7429 // with some sort of whitelist. OTOH, it seems that GCC is always
7430 // conservative with the last element in structs (if it's an array), so our
7431 // current behavior is more compatible than a whitelisting approach would
7433 return LVal.InvalidBase &&
7434 Designator.Entries.size() == Designator.MostDerivedPathLength &&
7435 Designator.MostDerivedIsArrayElement &&
7436 isDesignatorAtObjectEnd(Ctx, LVal);
7439 /// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
7440 /// Fails if the conversion would cause loss of precision.
7441 static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
7442 CharUnits &Result) {
7443 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
7444 if (Int.ugt(CharUnitsMax))
7446 Result = CharUnits::fromQuantity(Int.getZExtValue());
7450 /// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
7451 /// determine how many bytes exist from the beginning of the object to either
7452 /// the end of the current subobject, or the end of the object itself, depending
7453 /// on what the LValue looks like + the value of Type.
7455 /// If this returns false, the value of Result is undefined.
7456 static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
7457 unsigned Type, const LValue &LVal,
7458 CharUnits &EndOffset) {
7459 bool DetermineForCompleteObject = refersToCompleteObject(LVal);
7461 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
7462 if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
7464 return HandleSizeof(Info, ExprLoc, Ty, Result);
7467 // We want to evaluate the size of the entire object. This is a valid fallback
7468 // for when Type=1 and the designator is invalid, because we're asked for an
7470 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
7471 // Type=3 wants a lower bound, so we can't fall back to this.
7472 if (Type == 3 && !DetermineForCompleteObject)
7475 llvm::APInt APEndOffset;
7476 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
7477 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
7478 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
7480 if (LVal.InvalidBase)
7483 QualType BaseTy = getObjectType(LVal.getLValueBase());
7484 return CheckedHandleSizeof(BaseTy, EndOffset);
7487 // We want to evaluate the size of a subobject.
7488 const SubobjectDesignator &Designator = LVal.Designator;
7490 // The following is a moderately common idiom in C:
7492 // struct Foo { int a; char c[1]; };
7493 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
7494 // strcpy(&F->c[0], Bar);
7496 // In order to not break too much legacy code, we need to support it.
7497 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) {
7498 // If we can resolve this to an alloc_size call, we can hand that back,
7499 // because we know for certain how many bytes there are to write to.
7500 llvm::APInt APEndOffset;
7501 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
7502 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
7503 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
7505 // If we cannot determine the size of the initial allocation, then we can't
7506 // given an accurate upper-bound. However, we are still able to give
7507 // conservative lower-bounds for Type=3.
7512 CharUnits BytesPerElem;
7513 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
7516 // According to the GCC documentation, we want the size of the subobject
7517 // denoted by the pointer. But that's not quite right -- what we actually
7518 // want is the size of the immediately-enclosing array, if there is one.
7519 int64_t ElemsRemaining;
7520 if (Designator.MostDerivedIsArrayElement &&
7521 Designator.Entries.size() == Designator.MostDerivedPathLength) {
7522 uint64_t ArraySize = Designator.getMostDerivedArraySize();
7523 uint64_t ArrayIndex = Designator.Entries.back().ArrayIndex;
7524 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
7526 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
7529 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
7533 /// \brief Tries to evaluate the __builtin_object_size for @p E. If successful,
7534 /// returns true and stores the result in @p Size.
7536 /// If @p WasError is non-null, this will report whether the failure to evaluate
7537 /// is to be treated as an Error in IntExprEvaluator.
7538 static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
7539 EvalInfo &Info, uint64_t &Size) {
7540 // Determine the denoted object.
7543 // The operand of __builtin_object_size is never evaluated for side-effects.
7544 // If there are any, but we can determine the pointed-to object anyway, then
7545 // ignore the side-effects.
7546 SpeculativeEvaluationRAII SpeculativeEval(Info);
7547 FoldOffsetRAII Fold(Info);
7549 if (E->isGLValue()) {
7550 // It's possible for us to be given GLValues if we're called via
7551 // Expr::tryEvaluateObjectSize.
7553 if (!EvaluateAsRValue(Info, E, RVal))
7555 LVal.setFrom(Info.Ctx, RVal);
7556 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info,
7557 /*InvalidBaseOK=*/true))
7561 // If we point to before the start of the object, there are no accessible
7563 if (LVal.getLValueOffset().isNegative()) {
7568 CharUnits EndOffset;
7569 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset))
7572 // If we've fallen outside of the end offset, just pretend there's nothing to
7573 // write to/read from.
7574 if (EndOffset <= LVal.getLValueOffset())
7577 Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
7581 bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
7582 if (unsigned BuiltinOp = E->getBuiltinCallee())
7583 return VisitBuiltinCallExpr(E, BuiltinOp);
7585 return ExprEvaluatorBaseTy::VisitCallExpr(E);
7588 bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
7589 unsigned BuiltinOp) {
7590 switch (unsigned BuiltinOp = E->getBuiltinCallee()) {
7592 return ExprEvaluatorBaseTy::VisitCallExpr(E);
7594 case Builtin::BI__builtin_object_size: {
7595 // The type was checked when we built the expression.
7597 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
7598 assert(Type <= 3 && "unexpected type");
7601 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size))
7602 return Success(Size, E);
7604 if (E->getArg(0)->HasSideEffects(Info.Ctx))
7605 return Success((Type & 2) ? 0 : -1, E);
7607 // Expression had no side effects, but we couldn't statically determine the
7608 // size of the referenced object.
7609 switch (Info.EvalMode) {
7610 case EvalInfo::EM_ConstantExpression:
7611 case EvalInfo::EM_PotentialConstantExpression:
7612 case EvalInfo::EM_ConstantFold:
7613 case EvalInfo::EM_EvaluateForOverflow:
7614 case EvalInfo::EM_IgnoreSideEffects:
7615 case EvalInfo::EM_OffsetFold:
7616 // Leave it to IR generation.
7618 case EvalInfo::EM_ConstantExpressionUnevaluated:
7619 case EvalInfo::EM_PotentialConstantExpressionUnevaluated:
7620 // Reduce it to a constant now.
7621 return Success((Type & 2) ? 0 : -1, E);
7624 llvm_unreachable("unexpected EvalMode");
7627 case Builtin::BI__builtin_bswap16:
7628 case Builtin::BI__builtin_bswap32:
7629 case Builtin::BI__builtin_bswap64: {
7631 if (!EvaluateInteger(E->getArg(0), Val, Info))
7634 return Success(Val.byteSwap(), E);
7637 case Builtin::BI__builtin_classify_type:
7638 return Success(EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E);
7640 // FIXME: BI__builtin_clrsb
7641 // FIXME: BI__builtin_clrsbl
7642 // FIXME: BI__builtin_clrsbll
7644 case Builtin::BI__builtin_clz:
7645 case Builtin::BI__builtin_clzl:
7646 case Builtin::BI__builtin_clzll:
7647 case Builtin::BI__builtin_clzs: {
7649 if (!EvaluateInteger(E->getArg(0), Val, Info))
7654 return Success(Val.countLeadingZeros(), E);
7657 case Builtin::BI__builtin_constant_p:
7658 return Success(EvaluateBuiltinConstantP(Info.Ctx, E->getArg(0)), E);
7660 case Builtin::BI__builtin_ctz:
7661 case Builtin::BI__builtin_ctzl:
7662 case Builtin::BI__builtin_ctzll:
7663 case Builtin::BI__builtin_ctzs: {
7665 if (!EvaluateInteger(E->getArg(0), Val, Info))
7670 return Success(Val.countTrailingZeros(), E);
7673 case Builtin::BI__builtin_eh_return_data_regno: {
7674 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
7675 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
7676 return Success(Operand, E);
7679 case Builtin::BI__builtin_expect:
7680 return Visit(E->getArg(0));
7682 case Builtin::BI__builtin_ffs:
7683 case Builtin::BI__builtin_ffsl:
7684 case Builtin::BI__builtin_ffsll: {
7686 if (!EvaluateInteger(E->getArg(0), Val, Info))
7689 unsigned N = Val.countTrailingZeros();
7690 return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
7693 case Builtin::BI__builtin_fpclassify: {
7695 if (!EvaluateFloat(E->getArg(5), Val, Info))
7698 switch (Val.getCategory()) {
7699 case APFloat::fcNaN: Arg = 0; break;
7700 case APFloat::fcInfinity: Arg = 1; break;
7701 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
7702 case APFloat::fcZero: Arg = 4; break;
7704 return Visit(E->getArg(Arg));
7707 case Builtin::BI__builtin_isinf_sign: {
7709 return EvaluateFloat(E->getArg(0), Val, Info) &&
7710 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
7713 case Builtin::BI__builtin_isinf: {
7715 return EvaluateFloat(E->getArg(0), Val, Info) &&
7716 Success(Val.isInfinity() ? 1 : 0, E);
7719 case Builtin::BI__builtin_isfinite: {
7721 return EvaluateFloat(E->getArg(0), Val, Info) &&
7722 Success(Val.isFinite() ? 1 : 0, E);
7725 case Builtin::BI__builtin_isnan: {
7727 return EvaluateFloat(E->getArg(0), Val, Info) &&
7728 Success(Val.isNaN() ? 1 : 0, E);
7731 case Builtin::BI__builtin_isnormal: {
7733 return EvaluateFloat(E->getArg(0), Val, Info) &&
7734 Success(Val.isNormal() ? 1 : 0, E);
7737 case Builtin::BI__builtin_parity:
7738 case Builtin::BI__builtin_parityl:
7739 case Builtin::BI__builtin_parityll: {
7741 if (!EvaluateInteger(E->getArg(0), Val, Info))
7744 return Success(Val.countPopulation() % 2, E);
7747 case Builtin::BI__builtin_popcount:
7748 case Builtin::BI__builtin_popcountl:
7749 case Builtin::BI__builtin_popcountll: {
7751 if (!EvaluateInteger(E->getArg(0), Val, Info))
7754 return Success(Val.countPopulation(), E);
7757 case Builtin::BIstrlen:
7758 case Builtin::BIwcslen:
7759 // A call to strlen is not a constant expression.
7760 if (Info.getLangOpts().CPlusPlus11)
7761 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
7762 << /*isConstexpr*/0 << /*isConstructor*/0
7763 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
7765 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
7767 case Builtin::BI__builtin_strlen:
7768 case Builtin::BI__builtin_wcslen: {
7769 // As an extension, we support __builtin_strlen() as a constant expression,
7770 // and support folding strlen() to a constant.
7772 if (!EvaluatePointer(E->getArg(0), String, Info))
7775 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
7777 // Fast path: if it's a string literal, search the string value.
7778 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
7779 String.getLValueBase().dyn_cast<const Expr *>())) {
7780 // The string literal may have embedded null characters. Find the first
7781 // one and truncate there.
7782 StringRef Str = S->getBytes();
7783 int64_t Off = String.Offset.getQuantity();
7784 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
7785 S->getCharByteWidth() == 1 &&
7786 // FIXME: Add fast-path for wchar_t too.
7787 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) {
7788 Str = Str.substr(Off);
7790 StringRef::size_type Pos = Str.find(0);
7791 if (Pos != StringRef::npos)
7792 Str = Str.substr(0, Pos);
7794 return Success(Str.size(), E);
7797 // Fall through to slow path to issue appropriate diagnostic.
7800 // Slow path: scan the bytes of the string looking for the terminating 0.
7801 for (uint64_t Strlen = 0; /**/; ++Strlen) {
7803 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) ||
7807 return Success(Strlen, E);
7808 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1))
7813 case Builtin::BIstrcmp:
7814 case Builtin::BIwcscmp:
7815 case Builtin::BIstrncmp:
7816 case Builtin::BIwcsncmp:
7817 case Builtin::BImemcmp:
7818 case Builtin::BIwmemcmp:
7819 // A call to strlen is not a constant expression.
7820 if (Info.getLangOpts().CPlusPlus11)
7821 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
7822 << /*isConstexpr*/0 << /*isConstructor*/0
7823 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
7825 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
7827 case Builtin::BI__builtin_strcmp:
7828 case Builtin::BI__builtin_wcscmp:
7829 case Builtin::BI__builtin_strncmp:
7830 case Builtin::BI__builtin_wcsncmp:
7831 case Builtin::BI__builtin_memcmp:
7832 case Builtin::BI__builtin_wmemcmp: {
7833 LValue String1, String2;
7834 if (!EvaluatePointer(E->getArg(0), String1, Info) ||
7835 !EvaluatePointer(E->getArg(1), String2, Info))
7838 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
7840 uint64_t MaxLength = uint64_t(-1);
7841 if (BuiltinOp != Builtin::BIstrcmp &&
7842 BuiltinOp != Builtin::BIwcscmp &&
7843 BuiltinOp != Builtin::BI__builtin_strcmp &&
7844 BuiltinOp != Builtin::BI__builtin_wcscmp) {
7846 if (!EvaluateInteger(E->getArg(2), N, Info))
7848 MaxLength = N.getExtValue();
7850 bool StopAtNull = (BuiltinOp != Builtin::BImemcmp &&
7851 BuiltinOp != Builtin::BIwmemcmp &&
7852 BuiltinOp != Builtin::BI__builtin_memcmp &&
7853 BuiltinOp != Builtin::BI__builtin_wmemcmp);
7854 for (; MaxLength; --MaxLength) {
7855 APValue Char1, Char2;
7856 if (!handleLValueToRValueConversion(Info, E, CharTy, String1, Char1) ||
7857 !handleLValueToRValueConversion(Info, E, CharTy, String2, Char2) ||
7858 !Char1.isInt() || !Char2.isInt())
7860 if (Char1.getInt() != Char2.getInt())
7861 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
7862 if (StopAtNull && !Char1.getInt())
7863 return Success(0, E);
7864 assert(!(StopAtNull && !Char2.getInt()));
7865 if (!HandleLValueArrayAdjustment(Info, E, String1, CharTy, 1) ||
7866 !HandleLValueArrayAdjustment(Info, E, String2, CharTy, 1))
7869 // We hit the strncmp / memcmp limit.
7870 return Success(0, E);
7873 case Builtin::BI__atomic_always_lock_free:
7874 case Builtin::BI__atomic_is_lock_free:
7875 case Builtin::BI__c11_atomic_is_lock_free: {
7877 if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
7880 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
7881 // of two less than the maximum inline atomic width, we know it is
7882 // lock-free. If the size isn't a power of two, or greater than the
7883 // maximum alignment where we promote atomics, we know it is not lock-free
7884 // (at least not in the sense of atomic_is_lock_free). Otherwise,
7885 // the answer can only be determined at runtime; for example, 16-byte
7886 // atomics have lock-free implementations on some, but not all,
7887 // x86-64 processors.
7889 // Check power-of-two.
7890 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
7891 if (Size.isPowerOfTwo()) {
7892 // Check against inlining width.
7893 unsigned InlineWidthBits =
7894 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
7895 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
7896 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
7897 Size == CharUnits::One() ||
7898 E->getArg(1)->isNullPointerConstant(Info.Ctx,
7899 Expr::NPC_NeverValueDependent))
7900 // OK, we will inline appropriately-aligned operations of this size,
7901 // and _Atomic(T) is appropriately-aligned.
7902 return Success(1, E);
7904 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
7905 castAs<PointerType>()->getPointeeType();
7906 if (!PointeeType->isIncompleteType() &&
7907 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
7908 // OK, we will inline operations on this object.
7909 return Success(1, E);
7914 return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
7915 Success(0, E) : Error(E);
7920 static bool HasSameBase(const LValue &A, const LValue &B) {
7921 if (!A.getLValueBase())
7922 return !B.getLValueBase();
7923 if (!B.getLValueBase())
7926 if (A.getLValueBase().getOpaqueValue() !=
7927 B.getLValueBase().getOpaqueValue()) {
7928 const Decl *ADecl = GetLValueBaseDecl(A);
7931 const Decl *BDecl = GetLValueBaseDecl(B);
7932 if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl())
7936 return IsGlobalLValue(A.getLValueBase()) ||
7937 A.getLValueCallIndex() == B.getLValueCallIndex();
7940 /// \brief Determine whether this is a pointer past the end of the complete
7941 /// object referred to by the lvalue.
7942 static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
7944 // A null pointer can be viewed as being "past the end" but we don't
7945 // choose to look at it that way here.
7946 if (!LV.getLValueBase())
7949 // If the designator is valid and refers to a subobject, we're not pointing
7951 if (!LV.getLValueDesignator().Invalid &&
7952 !LV.getLValueDesignator().isOnePastTheEnd())
7955 // A pointer to an incomplete type might be past-the-end if the type's size is
7956 // zero. We cannot tell because the type is incomplete.
7957 QualType Ty = getType(LV.getLValueBase());
7958 if (Ty->isIncompleteType())
7961 // We're a past-the-end pointer if we point to the byte after the object,
7962 // no matter what our type or path is.
7963 auto Size = Ctx.getTypeSizeInChars(Ty);
7964 return LV.getLValueOffset() == Size;
7969 /// \brief Data recursive integer evaluator of certain binary operators.
7971 /// We use a data recursive algorithm for binary operators so that we are able
7972 /// to handle extreme cases of chained binary operators without causing stack
7974 class DataRecursiveIntBinOpEvaluator {
7979 EvalResult() : Failed(false) { }
7981 void swap(EvalResult &RHS) {
7983 Failed = RHS.Failed;
7990 EvalResult LHSResult; // meaningful only for binary operator expression.
7991 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
7994 Job(Job &&) = default;
7996 void startSpeculativeEval(EvalInfo &Info) {
7997 SpecEvalRAII = SpeculativeEvaluationRAII(Info);
8001 SpeculativeEvaluationRAII SpecEvalRAII;
8004 SmallVector<Job, 16> Queue;
8006 IntExprEvaluator &IntEval;
8008 APValue &FinalResult;
8011 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
8012 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
8014 /// \brief True if \param E is a binary operator that we are going to handle
8015 /// data recursively.
8016 /// We handle binary operators that are comma, logical, or that have operands
8017 /// with integral or enumeration type.
8018 static bool shouldEnqueue(const BinaryOperator *E) {
8019 return E->getOpcode() == BO_Comma ||
8022 E->getType()->isIntegralOrEnumerationType() &&
8023 E->getLHS()->getType()->isIntegralOrEnumerationType() &&
8024 E->getRHS()->getType()->isIntegralOrEnumerationType());
8027 bool Traverse(const BinaryOperator *E) {
8029 EvalResult PrevResult;
8030 while (!Queue.empty())
8031 process(PrevResult);
8033 if (PrevResult.Failed) return false;
8035 FinalResult.swap(PrevResult.Val);
8040 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
8041 return IntEval.Success(Value, E, Result);
8043 bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
8044 return IntEval.Success(Value, E, Result);
8046 bool Error(const Expr *E) {
8047 return IntEval.Error(E);
8049 bool Error(const Expr *E, diag::kind D) {
8050 return IntEval.Error(E, D);
8053 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
8054 return Info.CCEDiag(E, D);
8057 // \brief Returns true if visiting the RHS is necessary, false otherwise.
8058 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
8059 bool &SuppressRHSDiags);
8061 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
8062 const BinaryOperator *E, APValue &Result);
8064 void EvaluateExpr(const Expr *E, EvalResult &Result) {
8065 Result.Failed = !Evaluate(Result.Val, Info, E);
8067 Result.Val = APValue();
8070 void process(EvalResult &Result);
8072 void enqueue(const Expr *E) {
8073 E = E->IgnoreParens();
8074 Queue.resize(Queue.size()+1);
8076 Queue.back().Kind = Job::AnyExprKind;
8082 bool DataRecursiveIntBinOpEvaluator::
8083 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
8084 bool &SuppressRHSDiags) {
8085 if (E->getOpcode() == BO_Comma) {
8086 // Ignore LHS but note if we could not evaluate it.
8087 if (LHSResult.Failed)
8088 return Info.noteSideEffect();
8092 if (E->isLogicalOp()) {
8094 if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) {
8095 // We were able to evaluate the LHS, see if we can get away with not
8096 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
8097 if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
8098 Success(LHSAsBool, E, LHSResult.Val);
8099 return false; // Ignore RHS
8102 LHSResult.Failed = true;
8104 // Since we weren't able to evaluate the left hand side, it
8105 // might have had side effects.
8106 if (!Info.noteSideEffect())
8109 // We can't evaluate the LHS; however, sometimes the result
8110 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
8111 // Don't ignore RHS and suppress diagnostics from this arm.
8112 SuppressRHSDiags = true;
8118 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
8119 E->getRHS()->getType()->isIntegralOrEnumerationType());
8121 if (LHSResult.Failed && !Info.noteFailure())
8122 return false; // Ignore RHS;
8127 static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index,
8129 // Compute the new offset in the appropriate width, wrapping at 64 bits.
8130 // FIXME: When compiling for a 32-bit target, we should use 32-bit
8132 assert(!LVal.hasLValuePath() && "have designator for integer lvalue");
8133 CharUnits &Offset = LVal.getLValueOffset();
8134 uint64_t Offset64 = Offset.getQuantity();
8135 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
8136 Offset = CharUnits::fromQuantity(IsSub ? Offset64 - Index64
8137 : Offset64 + Index64);
8140 bool DataRecursiveIntBinOpEvaluator::
8141 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
8142 const BinaryOperator *E, APValue &Result) {
8143 if (E->getOpcode() == BO_Comma) {
8144 if (RHSResult.Failed)
8146 Result = RHSResult.Val;
8150 if (E->isLogicalOp()) {
8151 bool lhsResult, rhsResult;
8152 bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
8153 bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);
8157 if (E->getOpcode() == BO_LOr)
8158 return Success(lhsResult || rhsResult, E, Result);
8160 return Success(lhsResult && rhsResult, E, Result);
8164 // We can't evaluate the LHS; however, sometimes the result
8165 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
8166 if (rhsResult == (E->getOpcode() == BO_LOr))
8167 return Success(rhsResult, E, Result);
8174 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
8175 E->getRHS()->getType()->isIntegralOrEnumerationType());
8177 if (LHSResult.Failed || RHSResult.Failed)
8180 const APValue &LHSVal = LHSResult.Val;
8181 const APValue &RHSVal = RHSResult.Val;
8183 // Handle cases like (unsigned long)&a + 4.
8184 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
8186 addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub);
8190 // Handle cases like 4 + (unsigned long)&a
8191 if (E->getOpcode() == BO_Add &&
8192 RHSVal.isLValue() && LHSVal.isInt()) {
8194 addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false);
8198 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
8199 // Handle (intptr_t)&&A - (intptr_t)&&B.
8200 if (!LHSVal.getLValueOffset().isZero() ||
8201 !RHSVal.getLValueOffset().isZero())
8203 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
8204 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
8205 if (!LHSExpr || !RHSExpr)
8207 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
8208 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
8209 if (!LHSAddrExpr || !RHSAddrExpr)
8211 // Make sure both labels come from the same function.
8212 if (LHSAddrExpr->getLabel()->getDeclContext() !=
8213 RHSAddrExpr->getLabel()->getDeclContext())
8215 Result = APValue(LHSAddrExpr, RHSAddrExpr);
8219 // All the remaining cases expect both operands to be an integer
8220 if (!LHSVal.isInt() || !RHSVal.isInt())
8223 // Set up the width and signedness manually, in case it can't be deduced
8224 // from the operation we're performing.
8225 // FIXME: Don't do this in the cases where we can deduce it.
8226 APSInt Value(Info.Ctx.getIntWidth(E->getType()),
8227 E->getType()->isUnsignedIntegerOrEnumerationType());
8228 if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(),
8229 RHSVal.getInt(), Value))
8231 return Success(Value, E, Result);
8234 void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
8235 Job &job = Queue.back();
8238 case Job::AnyExprKind: {
8239 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
8240 if (shouldEnqueue(Bop)) {
8241 job.Kind = Job::BinOpKind;
8242 enqueue(Bop->getLHS());
8247 EvaluateExpr(job.E, Result);
8252 case Job::BinOpKind: {
8253 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
8254 bool SuppressRHSDiags = false;
8255 if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) {
8259 if (SuppressRHSDiags)
8260 job.startSpeculativeEval(Info);
8261 job.LHSResult.swap(Result);
8262 job.Kind = Job::BinOpVisitedLHSKind;
8263 enqueue(Bop->getRHS());
8267 case Job::BinOpVisitedLHSKind: {
8268 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
8271 Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val);
8277 llvm_unreachable("Invalid Job::Kind!");
8281 /// Used when we determine that we should fail, but can keep evaluating prior to
8282 /// noting that we had a failure.
8283 class DelayedNoteFailureRAII {
8288 DelayedNoteFailureRAII(EvalInfo &Info, bool NoteFailure = true)
8289 : Info(Info), NoteFailure(NoteFailure) {}
8290 ~DelayedNoteFailureRAII() {
8292 bool ContinueAfterFailure = Info.noteFailure();
8293 (void)ContinueAfterFailure;
8294 assert(ContinueAfterFailure &&
8295 "Shouldn't have kept evaluating on failure.");
8301 bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
8302 // We don't call noteFailure immediately because the assignment happens after
8303 // we evaluate LHS and RHS.
8304 if (!Info.keepEvaluatingAfterFailure() && E->isAssignmentOp())
8307 DelayedNoteFailureRAII MaybeNoteFailureLater(Info, E->isAssignmentOp());
8308 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
8309 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
8311 QualType LHSTy = E->getLHS()->getType();
8312 QualType RHSTy = E->getRHS()->getType();
8314 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
8315 ComplexValue LHS, RHS;
8317 if (E->isAssignmentOp()) {
8319 EvaluateLValue(E->getLHS(), LV, Info);
8321 } else if (LHSTy->isRealFloatingType()) {
8322 LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info);
8324 LHS.makeComplexFloat();
8325 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
8328 LHSOK = EvaluateComplex(E->getLHS(), LHS, Info);
8330 if (!LHSOK && !Info.noteFailure())
8333 if (E->getRHS()->getType()->isRealFloatingType()) {
8334 if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK)
8336 RHS.makeComplexFloat();
8337 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
8338 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
8341 if (LHS.isComplexFloat()) {
8342 APFloat::cmpResult CR_r =
8343 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
8344 APFloat::cmpResult CR_i =
8345 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
8347 if (E->getOpcode() == BO_EQ)
8348 return Success((CR_r == APFloat::cmpEqual &&
8349 CR_i == APFloat::cmpEqual), E);
8351 assert(E->getOpcode() == BO_NE &&
8352 "Invalid complex comparison.");
8353 return Success(((CR_r == APFloat::cmpGreaterThan ||
8354 CR_r == APFloat::cmpLessThan ||
8355 CR_r == APFloat::cmpUnordered) ||
8356 (CR_i == APFloat::cmpGreaterThan ||
8357 CR_i == APFloat::cmpLessThan ||
8358 CR_i == APFloat::cmpUnordered)), E);
8361 if (E->getOpcode() == BO_EQ)
8362 return Success((LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
8363 LHS.getComplexIntImag() == RHS.getComplexIntImag()), E);
8365 assert(E->getOpcode() == BO_NE &&
8366 "Invalid compex comparison.");
8367 return Success((LHS.getComplexIntReal() != RHS.getComplexIntReal() ||
8368 LHS.getComplexIntImag() != RHS.getComplexIntImag()), E);
8373 if (LHSTy->isRealFloatingType() &&
8374 RHSTy->isRealFloatingType()) {
8375 APFloat RHS(0.0), LHS(0.0);
8377 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info);
8378 if (!LHSOK && !Info.noteFailure())
8381 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK)
8384 APFloat::cmpResult CR = LHS.compare(RHS);
8386 switch (E->getOpcode()) {
8388 llvm_unreachable("Invalid binary operator!");
8390 return Success(CR == APFloat::cmpLessThan, E);
8392 return Success(CR == APFloat::cmpGreaterThan, E);
8394 return Success(CR == APFloat::cmpLessThan || CR == APFloat::cmpEqual, E);
8396 return Success(CR == APFloat::cmpGreaterThan || CR == APFloat::cmpEqual,
8399 return Success(CR == APFloat::cmpEqual, E);
8401 return Success(CR == APFloat::cmpGreaterThan
8402 || CR == APFloat::cmpLessThan
8403 || CR == APFloat::cmpUnordered, E);
8407 if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
8408 if (E->getOpcode() == BO_Sub || E->isComparisonOp()) {
8409 LValue LHSValue, RHSValue;
8411 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
8412 if (!LHSOK && !Info.noteFailure())
8415 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
8418 // Reject differing bases from the normal codepath; we special-case
8419 // comparisons to null.
8420 if (!HasSameBase(LHSValue, RHSValue)) {
8421 if (E->getOpcode() == BO_Sub) {
8422 // Handle &&A - &&B.
8423 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
8425 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr*>();
8426 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr*>();
8427 if (!LHSExpr || !RHSExpr)
8429 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
8430 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
8431 if (!LHSAddrExpr || !RHSAddrExpr)
8433 // Make sure both labels come from the same function.
8434 if (LHSAddrExpr->getLabel()->getDeclContext() !=
8435 RHSAddrExpr->getLabel()->getDeclContext())
8437 return Success(APValue(LHSAddrExpr, RHSAddrExpr), E);
8439 // Inequalities and subtractions between unrelated pointers have
8440 // unspecified or undefined behavior.
8441 if (!E->isEqualityOp())
8443 // A constant address may compare equal to the address of a symbol.
8444 // The one exception is that address of an object cannot compare equal
8445 // to a null pointer constant.
8446 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
8447 (!RHSValue.Base && !RHSValue.Offset.isZero()))
8449 // It's implementation-defined whether distinct literals will have
8450 // distinct addresses. In clang, the result of such a comparison is
8451 // unspecified, so it is not a constant expression. However, we do know
8452 // that the address of a literal will be non-null.
8453 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
8454 LHSValue.Base && RHSValue.Base)
8456 // We can't tell whether weak symbols will end up pointing to the same
8458 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
8460 // We can't compare the address of the start of one object with the
8461 // past-the-end address of another object, per C++ DR1652.
8462 if ((LHSValue.Base && LHSValue.Offset.isZero() &&
8463 isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) ||
8464 (RHSValue.Base && RHSValue.Offset.isZero() &&
8465 isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)))
8467 // We can't tell whether an object is at the same address as another
8468 // zero sized object.
8469 if ((RHSValue.Base && isZeroSized(LHSValue)) ||
8470 (LHSValue.Base && isZeroSized(RHSValue)))
8472 // Pointers with different bases cannot represent the same object.
8473 // (Note that clang defaults to -fmerge-all-constants, which can
8474 // lead to inconsistent results for comparisons involving the address
8475 // of a constant; this generally doesn't matter in practice.)
8476 return Success(E->getOpcode() == BO_NE, E);
8479 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
8480 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
8482 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
8483 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
8485 if (E->getOpcode() == BO_Sub) {
8486 // C++11 [expr.add]p6:
8487 // Unless both pointers point to elements of the same array object, or
8488 // one past the last element of the array object, the behavior is
8490 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
8491 !AreElementsOfSameArray(getType(LHSValue.Base),
8492 LHSDesignator, RHSDesignator))
8493 CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);
8495 QualType Type = E->getLHS()->getType();
8496 QualType ElementType = Type->getAs<PointerType>()->getPointeeType();
8498 CharUnits ElementSize;
8499 if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize))
8502 // As an extension, a type may have zero size (empty struct or union in
8503 // C, array of zero length). Pointer subtraction in such cases has
8504 // undefined behavior, so is not constant.
8505 if (ElementSize.isZero()) {
8506 Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size)
8511 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
8512 // and produce incorrect results when it overflows. Such behavior
8513 // appears to be non-conforming, but is common, so perhaps we should
8514 // assume the standard intended for such cases to be undefined behavior
8515 // and check for them.
8517 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
8518 // overflow in the final conversion to ptrdiff_t.
8520 llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
8522 llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
8524 llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true), false);
8525 APSInt TrueResult = (LHS - RHS) / ElemSize;
8526 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType()));
8528 if (Result.extend(65) != TrueResult &&
8529 !HandleOverflow(Info, E, TrueResult, E->getType()))
8531 return Success(Result, E);
8534 // C++11 [expr.rel]p3:
8535 // Pointers to void (after pointer conversions) can be compared, with a
8536 // result defined as follows: If both pointers represent the same
8537 // address or are both the null pointer value, the result is true if the
8538 // operator is <= or >= and false otherwise; otherwise the result is
8540 // We interpret this as applying to pointers to *cv* void.
8541 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset &&
8542 E->isRelationalOp())
8543 CCEDiag(E, diag::note_constexpr_void_comparison);
8545 // C++11 [expr.rel]p2:
8546 // - If two pointers point to non-static data members of the same object,
8547 // or to subobjects or array elements fo such members, recursively, the
8548 // pointer to the later declared member compares greater provided the
8549 // two members have the same access control and provided their class is
8552 // - Otherwise pointer comparisons are unspecified.
8553 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
8554 E->isRelationalOp()) {
8557 FindDesignatorMismatch(getType(LHSValue.Base), LHSDesignator,
8558 RHSDesignator, WasArrayIndex);
8559 // At the point where the designators diverge, the comparison has a
8560 // specified value if:
8561 // - we are comparing array indices
8562 // - we are comparing fields of a union, or fields with the same access
8563 // Otherwise, the result is unspecified and thus the comparison is not a
8564 // constant expression.
8565 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
8566 Mismatch < RHSDesignator.Entries.size()) {
8567 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]);
8568 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]);
8570 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
8572 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
8573 << getAsBaseClass(LHSDesignator.Entries[Mismatch])
8574 << RF->getParent() << RF;
8576 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
8577 << getAsBaseClass(RHSDesignator.Entries[Mismatch])
8578 << LF->getParent() << LF;
8579 else if (!LF->getParent()->isUnion() &&
8580 LF->getAccess() != RF->getAccess())
8581 CCEDiag(E, diag::note_constexpr_pointer_comparison_differing_access)
8582 << LF << LF->getAccess() << RF << RF->getAccess()
8587 // The comparison here must be unsigned, and performed with the same
8588 // width as the pointer.
8589 unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy);
8590 uint64_t CompareLHS = LHSOffset.getQuantity();
8591 uint64_t CompareRHS = RHSOffset.getQuantity();
8592 assert(PtrSize <= 64 && "Unexpected pointer width");
8593 uint64_t Mask = ~0ULL >> (64 - PtrSize);
8597 // If there is a base and this is a relational operator, we can only
8598 // compare pointers within the object in question; otherwise, the result
8599 // depends on where the object is located in memory.
8600 if (!LHSValue.Base.isNull() && E->isRelationalOp()) {
8601 QualType BaseTy = getType(LHSValue.Base);
8602 if (BaseTy->isIncompleteType())
8604 CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy);
8605 uint64_t OffsetLimit = Size.getQuantity();
8606 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
8610 switch (E->getOpcode()) {
8611 default: llvm_unreachable("missing comparison operator");
8612 case BO_LT: return Success(CompareLHS < CompareRHS, E);
8613 case BO_GT: return Success(CompareLHS > CompareRHS, E);
8614 case BO_LE: return Success(CompareLHS <= CompareRHS, E);
8615 case BO_GE: return Success(CompareLHS >= CompareRHS, E);
8616 case BO_EQ: return Success(CompareLHS == CompareRHS, E);
8617 case BO_NE: return Success(CompareLHS != CompareRHS, E);
8622 if (LHSTy->isMemberPointerType()) {
8623 assert(E->isEqualityOp() && "unexpected member pointer operation");
8624 assert(RHSTy->isMemberPointerType() && "invalid comparison");
8626 MemberPtr LHSValue, RHSValue;
8628 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info);
8629 if (!LHSOK && !Info.noteFailure())
8632 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK)
8635 // C++11 [expr.eq]p2:
8636 // If both operands are null, they compare equal. Otherwise if only one is
8637 // null, they compare unequal.
8638 if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
8639 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
8640 return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E);
8643 // Otherwise if either is a pointer to a virtual member function, the
8644 // result is unspecified.
8645 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
8646 if (MD->isVirtual())
8647 CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
8648 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
8649 if (MD->isVirtual())
8650 CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
8652 // Otherwise they compare equal if and only if they would refer to the
8653 // same member of the same most derived object or the same subobject if
8654 // they were dereferenced with a hypothetical object of the associated
8656 bool Equal = LHSValue == RHSValue;
8657 return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E);
8660 if (LHSTy->isNullPtrType()) {
8661 assert(E->isComparisonOp() && "unexpected nullptr operation");
8662 assert(RHSTy->isNullPtrType() && "missing pointer conversion");
8663 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
8664 // are compared, the result is true of the operator is <=, >= or ==, and
8666 BinaryOperator::Opcode Opcode = E->getOpcode();
8667 return Success(Opcode == BO_EQ || Opcode == BO_LE || Opcode == BO_GE, E);
8670 assert((!LHSTy->isIntegralOrEnumerationType() ||
8671 !RHSTy->isIntegralOrEnumerationType()) &&
8672 "DataRecursiveIntBinOpEvaluator should have handled integral types");
8673 // We can't continue from here for non-integral types.
8674 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8677 /// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
8678 /// a result as the expression's type.
8679 bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
8680 const UnaryExprOrTypeTraitExpr *E) {
8681 switch(E->getKind()) {
8682 case UETT_AlignOf: {
8683 if (E->isArgumentType())
8684 return Success(GetAlignOfType(Info, E->getArgumentType()), E);
8686 return Success(GetAlignOfExpr(Info, E->getArgumentExpr()), E);
8689 case UETT_VecStep: {
8690 QualType Ty = E->getTypeOfArgument();
8692 if (Ty->isVectorType()) {
8693 unsigned n = Ty->castAs<VectorType>()->getNumElements();
8695 // The vec_step built-in functions that take a 3-component
8696 // vector return 4. (OpenCL 1.1 spec 6.11.12)
8700 return Success(n, E);
8702 return Success(1, E);
8706 QualType SrcTy = E->getTypeOfArgument();
8707 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
8708 // the result is the size of the referenced type."
8709 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
8710 SrcTy = Ref->getPointeeType();
8713 if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof))
8715 return Success(Sizeof, E);
8717 case UETT_OpenMPRequiredSimdAlign:
8718 assert(E->isArgumentType());
8720 Info.Ctx.toCharUnitsFromBits(
8721 Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType()))
8726 llvm_unreachable("unknown expr/type trait");
8729 bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
8731 unsigned n = OOE->getNumComponents();
8734 QualType CurrentType = OOE->getTypeSourceInfo()->getType();
8735 for (unsigned i = 0; i != n; ++i) {
8736 OffsetOfNode ON = OOE->getComponent(i);
8737 switch (ON.getKind()) {
8738 case OffsetOfNode::Array: {
8739 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
8741 if (!EvaluateInteger(Idx, IdxResult, Info))
8743 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
8746 CurrentType = AT->getElementType();
8747 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
8748 Result += IdxResult.getSExtValue() * ElementSize;
8752 case OffsetOfNode::Field: {
8753 FieldDecl *MemberDecl = ON.getField();
8754 const RecordType *RT = CurrentType->getAs<RecordType>();
8757 RecordDecl *RD = RT->getDecl();
8758 if (RD->isInvalidDecl()) return false;
8759 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
8760 unsigned i = MemberDecl->getFieldIndex();
8761 assert(i < RL.getFieldCount() && "offsetof field in wrong type");
8762 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
8763 CurrentType = MemberDecl->getType().getNonReferenceType();
8767 case OffsetOfNode::Identifier:
8768 llvm_unreachable("dependent __builtin_offsetof");
8770 case OffsetOfNode::Base: {
8771 CXXBaseSpecifier *BaseSpec = ON.getBase();
8772 if (BaseSpec->isVirtual())
8775 // Find the layout of the class whose base we are looking into.
8776 const RecordType *RT = CurrentType->getAs<RecordType>();
8779 RecordDecl *RD = RT->getDecl();
8780 if (RD->isInvalidDecl()) return false;
8781 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
8783 // Find the base class itself.
8784 CurrentType = BaseSpec->getType();
8785 const RecordType *BaseRT = CurrentType->getAs<RecordType>();
8789 // Add the offset to the base.
8790 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
8795 return Success(Result, OOE);
8798 bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
8799 switch (E->getOpcode()) {
8801 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
8805 // FIXME: Should extension allow i-c-e extension expressions in its scope?
8806 // If so, we could clear the diagnostic ID.
8807 return Visit(E->getSubExpr());
8809 // The result is just the value.
8810 return Visit(E->getSubExpr());
8812 if (!Visit(E->getSubExpr()))
8814 if (!Result.isInt()) return Error(E);
8815 const APSInt &Value = Result.getInt();
8816 if (Value.isSigned() && Value.isMinSignedValue() &&
8817 !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
8820 return Success(-Value, E);
8823 if (!Visit(E->getSubExpr()))
8825 if (!Result.isInt()) return Error(E);
8826 return Success(~Result.getInt(), E);
8830 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
8832 return Success(!bres, E);
8837 /// HandleCast - This is used to evaluate implicit or explicit casts where the
8838 /// result type is integer.
8839 bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
8840 const Expr *SubExpr = E->getSubExpr();
8841 QualType DestType = E->getType();
8842 QualType SrcType = SubExpr->getType();
8844 switch (E->getCastKind()) {
8845 case CK_BaseToDerived:
8846 case CK_DerivedToBase:
8847 case CK_UncheckedDerivedToBase:
8850 case CK_ArrayToPointerDecay:
8851 case CK_FunctionToPointerDecay:
8852 case CK_NullToPointer:
8853 case CK_NullToMemberPointer:
8854 case CK_BaseToDerivedMemberPointer:
8855 case CK_DerivedToBaseMemberPointer:
8856 case CK_ReinterpretMemberPointer:
8857 case CK_ConstructorConversion:
8858 case CK_IntegralToPointer:
8860 case CK_VectorSplat:
8861 case CK_IntegralToFloating:
8862 case CK_FloatingCast:
8863 case CK_CPointerToObjCPointerCast:
8864 case CK_BlockPointerToObjCPointerCast:
8865 case CK_AnyPointerToBlockPointerCast:
8866 case CK_ObjCObjectLValueCast:
8867 case CK_FloatingRealToComplex:
8868 case CK_FloatingComplexToReal:
8869 case CK_FloatingComplexCast:
8870 case CK_FloatingComplexToIntegralComplex:
8871 case CK_IntegralRealToComplex:
8872 case CK_IntegralComplexCast:
8873 case CK_IntegralComplexToFloatingComplex:
8874 case CK_BuiltinFnToFnPtr:
8875 case CK_ZeroToOCLEvent:
8876 case CK_ZeroToOCLQueue:
8877 case CK_NonAtomicToAtomic:
8878 case CK_AddressSpaceConversion:
8879 case CK_IntToOCLSampler:
8880 llvm_unreachable("invalid cast kind for integral value");
8884 case CK_LValueBitCast:
8885 case CK_ARCProduceObject:
8886 case CK_ARCConsumeObject:
8887 case CK_ARCReclaimReturnedObject:
8888 case CK_ARCExtendBlockObject:
8889 case CK_CopyAndAutoreleaseBlockObject:
8892 case CK_UserDefinedConversion:
8893 case CK_LValueToRValue:
8894 case CK_AtomicToNonAtomic:
8896 return ExprEvaluatorBaseTy::VisitCastExpr(E);
8898 case CK_MemberPointerToBoolean:
8899 case CK_PointerToBoolean:
8900 case CK_IntegralToBoolean:
8901 case CK_FloatingToBoolean:
8902 case CK_BooleanToSignedIntegral:
8903 case CK_FloatingComplexToBoolean:
8904 case CK_IntegralComplexToBoolean: {
8906 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info))
8908 uint64_t IntResult = BoolResult;
8909 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
8910 IntResult = (uint64_t)-1;
8911 return Success(IntResult, E);
8914 case CK_IntegralCast: {
8915 if (!Visit(SubExpr))
8918 if (!Result.isInt()) {
8919 // Allow casts of address-of-label differences if they are no-ops
8920 // or narrowing. (The narrowing case isn't actually guaranteed to
8921 // be constant-evaluatable except in some narrow cases which are hard
8922 // to detect here. We let it through on the assumption the user knows
8923 // what they are doing.)
8924 if (Result.isAddrLabelDiff())
8925 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
8926 // Only allow casts of lvalues if they are lossless.
8927 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
8930 return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
8931 Result.getInt()), E);
8934 case CK_PointerToIntegral: {
8935 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8938 if (!EvaluatePointer(SubExpr, LV, Info))
8941 if (LV.getLValueBase()) {
8942 // Only allow based lvalue casts if they are lossless.
8943 // FIXME: Allow a larger integer size than the pointer size, and allow
8944 // narrowing back down to pointer width in subsequent integral casts.
8945 // FIXME: Check integer type's active bits, not its type size.
8946 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
8949 LV.Designator.setInvalid();
8950 LV.moveInto(Result);
8955 if (LV.isNullPointer())
8956 V = Info.Ctx.getTargetNullPointerValue(SrcType);
8958 V = LV.getLValueOffset().getQuantity();
8960 APSInt AsInt = Info.Ctx.MakeIntValue(V, SrcType);
8961 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
8964 case CK_IntegralComplexToReal: {
8966 if (!EvaluateComplex(SubExpr, C, Info))
8968 return Success(C.getComplexIntReal(), E);
8971 case CK_FloatingToIntegral: {
8973 if (!EvaluateFloat(SubExpr, F, Info))
8977 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
8979 return Success(Value, E);
8983 llvm_unreachable("unknown cast resulting in integral value");
8986 bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
8987 if (E->getSubExpr()->getType()->isAnyComplexType()) {
8989 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
8991 if (!LV.isComplexInt())
8993 return Success(LV.getComplexIntReal(), E);
8996 return Visit(E->getSubExpr());
8999 bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
9000 if (E->getSubExpr()->getType()->isComplexIntegerType()) {
9002 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
9004 if (!LV.isComplexInt())
9006 return Success(LV.getComplexIntImag(), E);
9009 VisitIgnoredValue(E->getSubExpr());
9010 return Success(0, E);
9013 bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
9014 return Success(E->getPackLength(), E);
9017 bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
9018 return Success(E->getValue(), E);
9021 //===----------------------------------------------------------------------===//
9023 //===----------------------------------------------------------------------===//
9026 class FloatExprEvaluator
9027 : public ExprEvaluatorBase<FloatExprEvaluator> {
9030 FloatExprEvaluator(EvalInfo &info, APFloat &result)
9031 : ExprEvaluatorBaseTy(info), Result(result) {}
9033 bool Success(const APValue &V, const Expr *e) {
9034 Result = V.getFloat();
9038 bool ZeroInitialization(const Expr *E) {
9039 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
9043 bool VisitCallExpr(const CallExpr *E);
9045 bool VisitUnaryOperator(const UnaryOperator *E);
9046 bool VisitBinaryOperator(const BinaryOperator *E);
9047 bool VisitFloatingLiteral(const FloatingLiteral *E);
9048 bool VisitCastExpr(const CastExpr *E);
9050 bool VisitUnaryReal(const UnaryOperator *E);
9051 bool VisitUnaryImag(const UnaryOperator *E);
9053 // FIXME: Missing: array subscript of vector, member of vector
9055 } // end anonymous namespace
9057 static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
9058 assert(E->isRValue() && E->getType()->isRealFloatingType());
9059 return FloatExprEvaluator(Info, Result).Visit(E);
9062 static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
9066 llvm::APFloat &Result) {
9067 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
9068 if (!S) return false;
9070 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);
9074 // Treat empty strings as if they were zero.
9075 if (S->getString().empty())
9076 fill = llvm::APInt(32, 0);
9077 else if (S->getString().getAsInteger(0, fill))
9080 if (Context.getTargetInfo().isNan2008()) {
9082 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
9084 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
9086 // Prior to IEEE 754-2008, architectures were allowed to choose whether
9087 // the first bit of their significand was set for qNaN or sNaN. MIPS chose
9088 // a different encoding to what became a standard in 2008, and for pre-
9089 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
9090 // sNaN. This is now known as "legacy NaN" encoding.
9092 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
9094 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
9100 bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
9101 switch (E->getBuiltinCallee()) {
9103 return ExprEvaluatorBaseTy::VisitCallExpr(E);
9105 case Builtin::BI__builtin_huge_val:
9106 case Builtin::BI__builtin_huge_valf:
9107 case Builtin::BI__builtin_huge_vall:
9108 case Builtin::BI__builtin_inf:
9109 case Builtin::BI__builtin_inff:
9110 case Builtin::BI__builtin_infl: {
9111 const llvm::fltSemantics &Sem =
9112 Info.Ctx.getFloatTypeSemantics(E->getType());
9113 Result = llvm::APFloat::getInf(Sem);
9117 case Builtin::BI__builtin_nans:
9118 case Builtin::BI__builtin_nansf:
9119 case Builtin::BI__builtin_nansl:
9120 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
9125 case Builtin::BI__builtin_nan:
9126 case Builtin::BI__builtin_nanf:
9127 case Builtin::BI__builtin_nanl:
9128 // If this is __builtin_nan() turn this into a nan, otherwise we
9129 // can't constant fold it.
9130 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
9135 case Builtin::BI__builtin_fabs:
9136 case Builtin::BI__builtin_fabsf:
9137 case Builtin::BI__builtin_fabsl:
9138 if (!EvaluateFloat(E->getArg(0), Result, Info))
9141 if (Result.isNegative())
9142 Result.changeSign();
9145 // FIXME: Builtin::BI__builtin_powi
9146 // FIXME: Builtin::BI__builtin_powif
9147 // FIXME: Builtin::BI__builtin_powil
9149 case Builtin::BI__builtin_copysign:
9150 case Builtin::BI__builtin_copysignf:
9151 case Builtin::BI__builtin_copysignl: {
9153 if (!EvaluateFloat(E->getArg(0), Result, Info) ||
9154 !EvaluateFloat(E->getArg(1), RHS, Info))
9156 Result.copySign(RHS);
9162 bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
9163 if (E->getSubExpr()->getType()->isAnyComplexType()) {
9165 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
9167 Result = CV.FloatReal;
9171 return Visit(E->getSubExpr());
9174 bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
9175 if (E->getSubExpr()->getType()->isAnyComplexType()) {
9177 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
9179 Result = CV.FloatImag;
9183 VisitIgnoredValue(E->getSubExpr());
9184 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
9185 Result = llvm::APFloat::getZero(Sem);
9189 bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
9190 switch (E->getOpcode()) {
9191 default: return Error(E);
9193 return EvaluateFloat(E->getSubExpr(), Result, Info);
9195 if (!EvaluateFloat(E->getSubExpr(), Result, Info))
9197 Result.changeSign();
9202 bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
9203 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
9204 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
9207 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info);
9208 if (!LHSOK && !Info.noteFailure())
9210 return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK &&
9211 handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS);
9214 bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
9215 Result = E->getValue();
9219 bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
9220 const Expr* SubExpr = E->getSubExpr();
9222 switch (E->getCastKind()) {
9224 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9226 case CK_IntegralToFloating: {
9228 return EvaluateInteger(SubExpr, IntResult, Info) &&
9229 HandleIntToFloatCast(Info, E, SubExpr->getType(), IntResult,
9230 E->getType(), Result);
9233 case CK_FloatingCast: {
9234 if (!Visit(SubExpr))
9236 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
9240 case CK_FloatingComplexToReal: {
9242 if (!EvaluateComplex(SubExpr, V, Info))
9244 Result = V.getComplexFloatReal();
9250 //===----------------------------------------------------------------------===//
9251 // Complex Evaluation (for float and integer)
9252 //===----------------------------------------------------------------------===//
9255 class ComplexExprEvaluator
9256 : public ExprEvaluatorBase<ComplexExprEvaluator> {
9257 ComplexValue &Result;
9260 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
9261 : ExprEvaluatorBaseTy(info), Result(Result) {}
9263 bool Success(const APValue &V, const Expr *e) {
9268 bool ZeroInitialization(const Expr *E);
9270 //===--------------------------------------------------------------------===//
9272 //===--------------------------------------------------------------------===//
9274 bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
9275 bool VisitCastExpr(const CastExpr *E);
9276 bool VisitBinaryOperator(const BinaryOperator *E);
9277 bool VisitUnaryOperator(const UnaryOperator *E);
9278 bool VisitInitListExpr(const InitListExpr *E);
9280 } // end anonymous namespace
9282 static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
9284 assert(E->isRValue() && E->getType()->isAnyComplexType());
9285 return ComplexExprEvaluator(Info, Result).Visit(E);
9288 bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
9289 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
9290 if (ElemTy->isRealFloatingType()) {
9291 Result.makeComplexFloat();
9292 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy));
9293 Result.FloatReal = Zero;
9294 Result.FloatImag = Zero;
9296 Result.makeComplexInt();
9297 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy);
9298 Result.IntReal = Zero;
9299 Result.IntImag = Zero;
9304 bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
9305 const Expr* SubExpr = E->getSubExpr();
9307 if (SubExpr->getType()->isRealFloatingType()) {
9308 Result.makeComplexFloat();
9309 APFloat &Imag = Result.FloatImag;
9310 if (!EvaluateFloat(SubExpr, Imag, Info))
9313 Result.FloatReal = APFloat(Imag.getSemantics());
9316 assert(SubExpr->getType()->isIntegerType() &&
9317 "Unexpected imaginary literal.");
9319 Result.makeComplexInt();
9320 APSInt &Imag = Result.IntImag;
9321 if (!EvaluateInteger(SubExpr, Imag, Info))
9324 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
9329 bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
9331 switch (E->getCastKind()) {
9333 case CK_BaseToDerived:
9334 case CK_DerivedToBase:
9335 case CK_UncheckedDerivedToBase:
9338 case CK_ArrayToPointerDecay:
9339 case CK_FunctionToPointerDecay:
9340 case CK_NullToPointer:
9341 case CK_NullToMemberPointer:
9342 case CK_BaseToDerivedMemberPointer:
9343 case CK_DerivedToBaseMemberPointer:
9344 case CK_MemberPointerToBoolean:
9345 case CK_ReinterpretMemberPointer:
9346 case CK_ConstructorConversion:
9347 case CK_IntegralToPointer:
9348 case CK_PointerToIntegral:
9349 case CK_PointerToBoolean:
9351 case CK_VectorSplat:
9352 case CK_IntegralCast:
9353 case CK_BooleanToSignedIntegral:
9354 case CK_IntegralToBoolean:
9355 case CK_IntegralToFloating:
9356 case CK_FloatingToIntegral:
9357 case CK_FloatingToBoolean:
9358 case CK_FloatingCast:
9359 case CK_CPointerToObjCPointerCast:
9360 case CK_BlockPointerToObjCPointerCast:
9361 case CK_AnyPointerToBlockPointerCast:
9362 case CK_ObjCObjectLValueCast:
9363 case CK_FloatingComplexToReal:
9364 case CK_FloatingComplexToBoolean:
9365 case CK_IntegralComplexToReal:
9366 case CK_IntegralComplexToBoolean:
9367 case CK_ARCProduceObject:
9368 case CK_ARCConsumeObject:
9369 case CK_ARCReclaimReturnedObject:
9370 case CK_ARCExtendBlockObject:
9371 case CK_CopyAndAutoreleaseBlockObject:
9372 case CK_BuiltinFnToFnPtr:
9373 case CK_ZeroToOCLEvent:
9374 case CK_ZeroToOCLQueue:
9375 case CK_NonAtomicToAtomic:
9376 case CK_AddressSpaceConversion:
9377 case CK_IntToOCLSampler:
9378 llvm_unreachable("invalid cast kind for complex value");
9380 case CK_LValueToRValue:
9381 case CK_AtomicToNonAtomic:
9383 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9386 case CK_LValueBitCast:
9387 case CK_UserDefinedConversion:
9390 case CK_FloatingRealToComplex: {
9391 APFloat &Real = Result.FloatReal;
9392 if (!EvaluateFloat(E->getSubExpr(), Real, Info))
9395 Result.makeComplexFloat();
9396 Result.FloatImag = APFloat(Real.getSemantics());
9400 case CK_FloatingComplexCast: {
9401 if (!Visit(E->getSubExpr()))
9404 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9406 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9408 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
9409 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
9412 case CK_FloatingComplexToIntegralComplex: {
9413 if (!Visit(E->getSubExpr()))
9416 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9418 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9419 Result.makeComplexInt();
9420 return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
9421 To, Result.IntReal) &&
9422 HandleFloatToIntCast(Info, E, From, Result.FloatImag,
9423 To, Result.IntImag);
9426 case CK_IntegralRealToComplex: {
9427 APSInt &Real = Result.IntReal;
9428 if (!EvaluateInteger(E->getSubExpr(), Real, Info))
9431 Result.makeComplexInt();
9432 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
9436 case CK_IntegralComplexCast: {
9437 if (!Visit(E->getSubExpr()))
9440 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9442 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9444 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
9445 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
9449 case CK_IntegralComplexToFloatingComplex: {
9450 if (!Visit(E->getSubExpr()))
9453 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
9455 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
9456 Result.makeComplexFloat();
9457 return HandleIntToFloatCast(Info, E, From, Result.IntReal,
9458 To, Result.FloatReal) &&
9459 HandleIntToFloatCast(Info, E, From, Result.IntImag,
9460 To, Result.FloatImag);
9464 llvm_unreachable("unknown cast resulting in complex value");
9467 bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
9468 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
9469 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
9471 // Track whether the LHS or RHS is real at the type system level. When this is
9472 // the case we can simplify our evaluation strategy.
9473 bool LHSReal = false, RHSReal = false;
9476 if (E->getLHS()->getType()->isRealFloatingType()) {
9478 APFloat &Real = Result.FloatReal;
9479 LHSOK = EvaluateFloat(E->getLHS(), Real, Info);
9481 Result.makeComplexFloat();
9482 Result.FloatImag = APFloat(Real.getSemantics());
9485 LHSOK = Visit(E->getLHS());
9487 if (!LHSOK && !Info.noteFailure())
9491 if (E->getRHS()->getType()->isRealFloatingType()) {
9493 APFloat &Real = RHS.FloatReal;
9494 if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK)
9496 RHS.makeComplexFloat();
9497 RHS.FloatImag = APFloat(Real.getSemantics());
9498 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
9501 assert(!(LHSReal && RHSReal) &&
9502 "Cannot have both operands of a complex operation be real.");
9503 switch (E->getOpcode()) {
9504 default: return Error(E);
9506 if (Result.isComplexFloat()) {
9507 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
9508 APFloat::rmNearestTiesToEven);
9510 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
9512 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
9513 APFloat::rmNearestTiesToEven);
9515 Result.getComplexIntReal() += RHS.getComplexIntReal();
9516 Result.getComplexIntImag() += RHS.getComplexIntImag();
9520 if (Result.isComplexFloat()) {
9521 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
9522 APFloat::rmNearestTiesToEven);
9524 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
9525 Result.getComplexFloatImag().changeSign();
9526 } else if (!RHSReal) {
9527 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
9528 APFloat::rmNearestTiesToEven);
9531 Result.getComplexIntReal() -= RHS.getComplexIntReal();
9532 Result.getComplexIntImag() -= RHS.getComplexIntImag();
9536 if (Result.isComplexFloat()) {
9537 // This is an implementation of complex multiplication according to the
9538 // constraints laid out in C11 Annex G. The implemantion uses the
9539 // following naming scheme:
9540 // (a + ib) * (c + id)
9541 ComplexValue LHS = Result;
9542 APFloat &A = LHS.getComplexFloatReal();
9543 APFloat &B = LHS.getComplexFloatImag();
9544 APFloat &C = RHS.getComplexFloatReal();
9545 APFloat &D = RHS.getComplexFloatImag();
9546 APFloat &ResR = Result.getComplexFloatReal();
9547 APFloat &ResI = Result.getComplexFloatImag();
9549 assert(!RHSReal && "Cannot have two real operands for a complex op!");
9552 } else if (RHSReal) {
9556 // In the fully general case, we need to handle NaNs and infinities
9564 if (ResR.isNaN() && ResI.isNaN()) {
9565 bool Recalc = false;
9566 if (A.isInfinity() || B.isInfinity()) {
9567 A = APFloat::copySign(
9568 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
9569 B = APFloat::copySign(
9570 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
9572 C = APFloat::copySign(APFloat(C.getSemantics()), C);
9574 D = APFloat::copySign(APFloat(D.getSemantics()), D);
9577 if (C.isInfinity() || D.isInfinity()) {
9578 C = APFloat::copySign(
9579 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
9580 D = APFloat::copySign(
9581 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
9583 A = APFloat::copySign(APFloat(A.getSemantics()), A);
9585 B = APFloat::copySign(APFloat(B.getSemantics()), B);
9588 if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
9589 AD.isInfinity() || BC.isInfinity())) {
9591 A = APFloat::copySign(APFloat(A.getSemantics()), A);
9593 B = APFloat::copySign(APFloat(B.getSemantics()), B);
9595 C = APFloat::copySign(APFloat(C.getSemantics()), C);
9597 D = APFloat::copySign(APFloat(D.getSemantics()), D);
9601 ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
9602 ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
9607 ComplexValue LHS = Result;
9608 Result.getComplexIntReal() =
9609 (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
9610 LHS.getComplexIntImag() * RHS.getComplexIntImag());
9611 Result.getComplexIntImag() =
9612 (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
9613 LHS.getComplexIntImag() * RHS.getComplexIntReal());
9617 if (Result.isComplexFloat()) {
9618 // This is an implementation of complex division according to the
9619 // constraints laid out in C11 Annex G. The implemantion uses the
9620 // following naming scheme:
9621 // (a + ib) / (c + id)
9622 ComplexValue LHS = Result;
9623 APFloat &A = LHS.getComplexFloatReal();
9624 APFloat &B = LHS.getComplexFloatImag();
9625 APFloat &C = RHS.getComplexFloatReal();
9626 APFloat &D = RHS.getComplexFloatImag();
9627 APFloat &ResR = Result.getComplexFloatReal();
9628 APFloat &ResI = Result.getComplexFloatImag();
9634 // No real optimizations we can do here, stub out with zero.
9635 B = APFloat::getZero(A.getSemantics());
9638 APFloat MaxCD = maxnum(abs(C), abs(D));
9639 if (MaxCD.isFinite()) {
9640 DenomLogB = ilogb(MaxCD);
9641 C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven);
9642 D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven);
9644 APFloat Denom = C * C + D * D;
9645 ResR = scalbn((A * C + B * D) / Denom, -DenomLogB,
9646 APFloat::rmNearestTiesToEven);
9647 ResI = scalbn((B * C - A * D) / Denom, -DenomLogB,
9648 APFloat::rmNearestTiesToEven);
9649 if (ResR.isNaN() && ResI.isNaN()) {
9650 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
9651 ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A;
9652 ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B;
9653 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
9655 A = APFloat::copySign(
9656 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
9657 B = APFloat::copySign(
9658 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
9659 ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D);
9660 ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D);
9661 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
9662 C = APFloat::copySign(
9663 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
9664 D = APFloat::copySign(
9665 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
9666 ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D);
9667 ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D);
9672 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
9673 return Error(E, diag::note_expr_divide_by_zero);
9675 ComplexValue LHS = Result;
9676 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
9677 RHS.getComplexIntImag() * RHS.getComplexIntImag();
9678 Result.getComplexIntReal() =
9679 (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
9680 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
9681 Result.getComplexIntImag() =
9682 (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
9683 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
9691 bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
9692 // Get the operand value into 'Result'.
9693 if (!Visit(E->getSubExpr()))
9696 switch (E->getOpcode()) {
9702 // The result is always just the subexpr.
9705 if (Result.isComplexFloat()) {
9706 Result.getComplexFloatReal().changeSign();
9707 Result.getComplexFloatImag().changeSign();
9710 Result.getComplexIntReal() = -Result.getComplexIntReal();
9711 Result.getComplexIntImag() = -Result.getComplexIntImag();
9715 if (Result.isComplexFloat())
9716 Result.getComplexFloatImag().changeSign();
9718 Result.getComplexIntImag() = -Result.getComplexIntImag();
9723 bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
9724 if (E->getNumInits() == 2) {
9725 if (E->getType()->isComplexType()) {
9726 Result.makeComplexFloat();
9727 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info))
9729 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info))
9732 Result.makeComplexInt();
9733 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info))
9735 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info))
9740 return ExprEvaluatorBaseTy::VisitInitListExpr(E);
9743 //===----------------------------------------------------------------------===//
9744 // Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
9745 // implicit conversion.
9746 //===----------------------------------------------------------------------===//
9749 class AtomicExprEvaluator :
9750 public ExprEvaluatorBase<AtomicExprEvaluator> {
9754 AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
9755 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
9757 bool Success(const APValue &V, const Expr *E) {
9762 bool ZeroInitialization(const Expr *E) {
9763 ImplicitValueInitExpr VIE(
9764 E->getType()->castAs<AtomicType>()->getValueType());
9765 // For atomic-qualified class (and array) types in C++, initialize the
9766 // _Atomic-wrapped subobject directly, in-place.
9767 return This ? EvaluateInPlace(Result, Info, *This, &VIE)
9768 : Evaluate(Result, Info, &VIE);
9771 bool VisitCastExpr(const CastExpr *E) {
9772 switch (E->getCastKind()) {
9774 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9775 case CK_NonAtomicToAtomic:
9776 return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr())
9777 : Evaluate(Result, Info, E->getSubExpr());
9781 } // end anonymous namespace
9783 static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
9785 assert(E->isRValue() && E->getType()->isAtomicType());
9786 return AtomicExprEvaluator(Info, This, Result).Visit(E);
9789 //===----------------------------------------------------------------------===//
9790 // Void expression evaluation, primarily for a cast to void on the LHS of a
9792 //===----------------------------------------------------------------------===//
9795 class VoidExprEvaluator
9796 : public ExprEvaluatorBase<VoidExprEvaluator> {
9798 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
9800 bool Success(const APValue &V, const Expr *e) { return true; }
9802 bool VisitCastExpr(const CastExpr *E) {
9803 switch (E->getCastKind()) {
9805 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9807 VisitIgnoredValue(E->getSubExpr());
9812 bool VisitCallExpr(const CallExpr *E) {
9813 switch (E->getBuiltinCallee()) {
9815 return ExprEvaluatorBaseTy::VisitCallExpr(E);
9816 case Builtin::BI__assume:
9817 case Builtin::BI__builtin_assume:
9818 // The argument is not evaluated!
9823 } // end anonymous namespace
9825 static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
9826 assert(E->isRValue() && E->getType()->isVoidType());
9827 return VoidExprEvaluator(Info).Visit(E);
9830 //===----------------------------------------------------------------------===//
9831 // Top level Expr::EvaluateAsRValue method.
9832 //===----------------------------------------------------------------------===//
9834 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
9835 // In C, function designators are not lvalues, but we evaluate them as if they
9837 QualType T = E->getType();
9838 if (E->isGLValue() || T->isFunctionType()) {
9840 if (!EvaluateLValue(E, LV, Info))
9842 LV.moveInto(Result);
9843 } else if (T->isVectorType()) {
9844 if (!EvaluateVector(E, Result, Info))
9846 } else if (T->isIntegralOrEnumerationType()) {
9847 if (!IntExprEvaluator(Info, Result).Visit(E))
9849 } else if (T->hasPointerRepresentation()) {
9851 if (!EvaluatePointer(E, LV, Info))
9853 LV.moveInto(Result);
9854 } else if (T->isRealFloatingType()) {
9855 llvm::APFloat F(0.0);
9856 if (!EvaluateFloat(E, F, Info))
9858 Result = APValue(F);
9859 } else if (T->isAnyComplexType()) {
9861 if (!EvaluateComplex(E, C, Info))
9864 } else if (T->isMemberPointerType()) {
9866 if (!EvaluateMemberPointer(E, P, Info))
9870 } else if (T->isArrayType()) {
9872 LV.set(E, Info.CurrentCall->Index);
9873 APValue &Value = Info.CurrentCall->createTemporary(E, false);
9874 if (!EvaluateArray(E, LV, Value, Info))
9877 } else if (T->isRecordType()) {
9879 LV.set(E, Info.CurrentCall->Index);
9880 APValue &Value = Info.CurrentCall->createTemporary(E, false);
9881 if (!EvaluateRecord(E, LV, Value, Info))
9884 } else if (T->isVoidType()) {
9885 if (!Info.getLangOpts().CPlusPlus11)
9886 Info.CCEDiag(E, diag::note_constexpr_nonliteral)
9888 if (!EvaluateVoid(E, Info))
9890 } else if (T->isAtomicType()) {
9891 QualType Unqual = T.getAtomicUnqualifiedType();
9892 if (Unqual->isArrayType() || Unqual->isRecordType()) {
9894 LV.set(E, Info.CurrentCall->Index);
9895 APValue &Value = Info.CurrentCall->createTemporary(E, false);
9896 if (!EvaluateAtomic(E, &LV, Value, Info))
9899 if (!EvaluateAtomic(E, nullptr, Result, Info))
9902 } else if (Info.getLangOpts().CPlusPlus11) {
9903 Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
9906 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
9913 /// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
9914 /// cases, the in-place evaluation is essential, since later initializers for
9915 /// an object can indirectly refer to subobjects which were initialized earlier.
9916 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
9917 const Expr *E, bool AllowNonLiteralTypes) {
9918 assert(!E->isValueDependent());
9920 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
9923 if (E->isRValue()) {
9924 // Evaluate arrays and record types in-place, so that later initializers can
9925 // refer to earlier-initialized members of the object.
9926 QualType T = E->getType();
9927 if (T->isArrayType())
9928 return EvaluateArray(E, This, Result, Info);
9929 else if (T->isRecordType())
9930 return EvaluateRecord(E, This, Result, Info);
9931 else if (T->isAtomicType()) {
9932 QualType Unqual = T.getAtomicUnqualifiedType();
9933 if (Unqual->isArrayType() || Unqual->isRecordType())
9934 return EvaluateAtomic(E, &This, Result, Info);
9938 // For any other type, in-place evaluation is unimportant.
9939 return Evaluate(Result, Info, E);
9942 /// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
9943 /// lvalue-to-rvalue cast if it is an lvalue.
9944 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
9945 if (E->getType().isNull())
9948 if (!CheckLiteralType(Info, E))
9951 if (!::Evaluate(Result, Info, E))
9954 if (E->isGLValue()) {
9956 LV.setFrom(Info.Ctx, Result);
9957 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
9961 // Check this core constant expression is a constant expression.
9962 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result);
9965 static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
9966 const ASTContext &Ctx, bool &IsConst,
9967 bool IsCheckingForOverflow) {
9968 // Fast-path evaluations of integer literals, since we sometimes see files
9969 // containing vast quantities of these.
9970 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) {
9971 Result.Val = APValue(APSInt(L->getValue(),
9972 L->getType()->isUnsignedIntegerType()));
9977 // This case should be rare, but we need to check it before we check on
9979 if (Exp->getType().isNull()) {
9984 // FIXME: Evaluating values of large array and record types can cause
9985 // performance problems. Only do so in C++11 for now.
9986 if (Exp->isRValue() && (Exp->getType()->isArrayType() ||
9987 Exp->getType()->isRecordType()) &&
9988 !Ctx.getLangOpts().CPlusPlus11 && !IsCheckingForOverflow) {
9996 /// EvaluateAsRValue - Return true if this is a constant which we can fold using
9997 /// any crazy technique (that has nothing to do with language standards) that
9998 /// we want to. If this function returns true, it returns the folded constant
9999 /// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
10000 /// will be applied to the result.
10001 bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const {
10003 if (FastEvaluateAsRValue(this, Result, Ctx, IsConst, false))
10006 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
10007 return ::EvaluateAsRValue(Info, this, Result.Val);
10010 bool Expr::EvaluateAsBooleanCondition(bool &Result,
10011 const ASTContext &Ctx) const {
10012 EvalResult Scratch;
10013 return EvaluateAsRValue(Scratch, Ctx) &&
10014 HandleConversionToBool(Scratch.Val, Result);
10017 static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
10018 Expr::SideEffectsKind SEK) {
10019 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
10020 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
10023 bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx,
10024 SideEffectsKind AllowSideEffects) const {
10025 if (!getType()->isIntegralOrEnumerationType())
10028 EvalResult ExprResult;
10029 if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isInt() ||
10030 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
10033 Result = ExprResult.Val.getInt();
10037 bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
10038 SideEffectsKind AllowSideEffects) const {
10039 if (!getType()->isRealFloatingType())
10042 EvalResult ExprResult;
10043 if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isFloat() ||
10044 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
10047 Result = ExprResult.Val.getFloat();
10051 bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const {
10052 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
10055 if (!EvaluateLValue(this, LV, Info) || Result.HasSideEffects ||
10056 !CheckLValueConstantExpression(Info, getExprLoc(),
10057 Ctx.getLValueReferenceType(getType()), LV))
10060 LV.moveInto(Result.Val);
10064 bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
10066 SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
10067 // FIXME: Evaluating initializers for large array and record types can cause
10068 // performance problems. Only do so in C++11 for now.
10069 if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
10070 !Ctx.getLangOpts().CPlusPlus11)
10073 Expr::EvalStatus EStatus;
10074 EStatus.Diag = &Notes;
10076 EvalInfo InitInfo(Ctx, EStatus, VD->isConstexpr()
10077 ? EvalInfo::EM_ConstantExpression
10078 : EvalInfo::EM_ConstantFold);
10079 InitInfo.setEvaluatingDecl(VD, Value);
10084 // C++11 [basic.start.init]p2:
10085 // Variables with static storage duration or thread storage duration shall be
10086 // zero-initialized before any other initialization takes place.
10087 // This behavior is not present in C.
10088 if (Ctx.getLangOpts().CPlusPlus && !VD->hasLocalStorage() &&
10089 !VD->getType()->isReferenceType()) {
10090 ImplicitValueInitExpr VIE(VD->getType());
10091 if (!EvaluateInPlace(Value, InitInfo, LVal, &VIE,
10092 /*AllowNonLiteralTypes=*/true))
10096 if (!EvaluateInPlace(Value, InitInfo, LVal, this,
10097 /*AllowNonLiteralTypes=*/true) ||
10098 EStatus.HasSideEffects)
10101 return CheckConstantExpression(InitInfo, VD->getLocation(), VD->getType(),
10105 /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
10106 /// constant folded, but discard the result.
10107 bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
10109 return EvaluateAsRValue(Result, Ctx) &&
10110 !hasUnacceptableSideEffect(Result, SEK);
10113 APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
10114 SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
10115 EvalResult EvalResult;
10116 EvalResult.Diag = Diag;
10117 bool Result = EvaluateAsRValue(EvalResult, Ctx);
10119 assert(Result && "Could not evaluate expression");
10120 assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer");
10122 return EvalResult.Val.getInt();
10125 void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
10127 EvalResult EvalResult;
10128 if (!FastEvaluateAsRValue(this, EvalResult, Ctx, IsConst, true)) {
10129 EvalInfo Info(Ctx, EvalResult, EvalInfo::EM_EvaluateForOverflow);
10130 (void)::EvaluateAsRValue(Info, this, EvalResult.Val);
10134 bool Expr::EvalResult::isGlobalLValue() const {
10135 assert(Val.isLValue());
10136 return IsGlobalLValue(Val.getLValueBase());
10140 /// isIntegerConstantExpr - this recursive routine will test if an expression is
10141 /// an integer constant expression.
10143 /// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
10146 // CheckICE - This function does the fundamental ICE checking: the returned
10147 // ICEDiag contains an ICEKind indicating whether the expression is an ICE,
10148 // and a (possibly null) SourceLocation indicating the location of the problem.
10150 // Note that to reduce code duplication, this helper does no evaluation
10151 // itself; the caller checks whether the expression is evaluatable, and
10152 // in the rare cases where CheckICE actually cares about the evaluated
10153 // value, it calls into Evaluate.
10158 /// This expression is an ICE.
10160 /// This expression is not an ICE, but if it isn't evaluated, it's
10161 /// a legal subexpression for an ICE. This return value is used to handle
10162 /// the comma operator in C99 mode, and non-constant subexpressions.
10163 IK_ICEIfUnevaluated,
10164 /// This expression is not an ICE, and is not a legal subexpression for one.
10170 SourceLocation Loc;
10172 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
10177 static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }
10179 static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }
10181 static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
10182 Expr::EvalResult EVResult;
10183 if (!E->EvaluateAsRValue(EVResult, Ctx) || EVResult.HasSideEffects ||
10184 !EVResult.Val.isInt())
10185 return ICEDiag(IK_NotICE, E->getLocStart());
10190 static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
10191 assert(!E->isValueDependent() && "Should not see value dependent exprs!");
10192 if (!E->getType()->isIntegralOrEnumerationType())
10193 return ICEDiag(IK_NotICE, E->getLocStart());
10195 switch (E->getStmtClass()) {
10196 #define ABSTRACT_STMT(Node)
10197 #define STMT(Node, Base) case Expr::Node##Class:
10198 #define EXPR(Node, Base)
10199 #include "clang/AST/StmtNodes.inc"
10200 case Expr::PredefinedExprClass:
10201 case Expr::FloatingLiteralClass:
10202 case Expr::ImaginaryLiteralClass:
10203 case Expr::StringLiteralClass:
10204 case Expr::ArraySubscriptExprClass:
10205 case Expr::OMPArraySectionExprClass:
10206 case Expr::MemberExprClass:
10207 case Expr::CompoundAssignOperatorClass:
10208 case Expr::CompoundLiteralExprClass:
10209 case Expr::ExtVectorElementExprClass:
10210 case Expr::DesignatedInitExprClass:
10211 case Expr::ArrayInitLoopExprClass:
10212 case Expr::ArrayInitIndexExprClass:
10213 case Expr::NoInitExprClass:
10214 case Expr::DesignatedInitUpdateExprClass:
10215 case Expr::ImplicitValueInitExprClass:
10216 case Expr::ParenListExprClass:
10217 case Expr::VAArgExprClass:
10218 case Expr::AddrLabelExprClass:
10219 case Expr::StmtExprClass:
10220 case Expr::CXXMemberCallExprClass:
10221 case Expr::CUDAKernelCallExprClass:
10222 case Expr::CXXDynamicCastExprClass:
10223 case Expr::CXXTypeidExprClass:
10224 case Expr::CXXUuidofExprClass:
10225 case Expr::MSPropertyRefExprClass:
10226 case Expr::MSPropertySubscriptExprClass:
10227 case Expr::CXXNullPtrLiteralExprClass:
10228 case Expr::UserDefinedLiteralClass:
10229 case Expr::CXXThisExprClass:
10230 case Expr::CXXThrowExprClass:
10231 case Expr::CXXNewExprClass:
10232 case Expr::CXXDeleteExprClass:
10233 case Expr::CXXPseudoDestructorExprClass:
10234 case Expr::UnresolvedLookupExprClass:
10235 case Expr::TypoExprClass:
10236 case Expr::DependentScopeDeclRefExprClass:
10237 case Expr::CXXConstructExprClass:
10238 case Expr::CXXInheritedCtorInitExprClass:
10239 case Expr::CXXStdInitializerListExprClass:
10240 case Expr::CXXBindTemporaryExprClass:
10241 case Expr::ExprWithCleanupsClass:
10242 case Expr::CXXTemporaryObjectExprClass:
10243 case Expr::CXXUnresolvedConstructExprClass:
10244 case Expr::CXXDependentScopeMemberExprClass:
10245 case Expr::UnresolvedMemberExprClass:
10246 case Expr::ObjCStringLiteralClass:
10247 case Expr::ObjCBoxedExprClass:
10248 case Expr::ObjCArrayLiteralClass:
10249 case Expr::ObjCDictionaryLiteralClass:
10250 case Expr::ObjCEncodeExprClass:
10251 case Expr::ObjCMessageExprClass:
10252 case Expr::ObjCSelectorExprClass:
10253 case Expr::ObjCProtocolExprClass:
10254 case Expr::ObjCIvarRefExprClass:
10255 case Expr::ObjCPropertyRefExprClass:
10256 case Expr::ObjCSubscriptRefExprClass:
10257 case Expr::ObjCIsaExprClass:
10258 case Expr::ObjCAvailabilityCheckExprClass:
10259 case Expr::ShuffleVectorExprClass:
10260 case Expr::ConvertVectorExprClass:
10261 case Expr::BlockExprClass:
10262 case Expr::NoStmtClass:
10263 case Expr::OpaqueValueExprClass:
10264 case Expr::PackExpansionExprClass:
10265 case Expr::SubstNonTypeTemplateParmPackExprClass:
10266 case Expr::FunctionParmPackExprClass:
10267 case Expr::AsTypeExprClass:
10268 case Expr::ObjCIndirectCopyRestoreExprClass:
10269 case Expr::MaterializeTemporaryExprClass:
10270 case Expr::PseudoObjectExprClass:
10271 case Expr::AtomicExprClass:
10272 case Expr::LambdaExprClass:
10273 case Expr::CXXFoldExprClass:
10274 case Expr::CoawaitExprClass:
10275 case Expr::DependentCoawaitExprClass:
10276 case Expr::CoyieldExprClass:
10277 return ICEDiag(IK_NotICE, E->getLocStart());
10279 case Expr::InitListExprClass: {
10280 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
10281 // form "T x = { a };" is equivalent to "T x = a;".
10282 // Unless we're initializing a reference, T is a scalar as it is known to be
10283 // of integral or enumeration type.
10285 if (cast<InitListExpr>(E)->getNumInits() == 1)
10286 return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx);
10287 return ICEDiag(IK_NotICE, E->getLocStart());
10290 case Expr::SizeOfPackExprClass:
10291 case Expr::GNUNullExprClass:
10292 // GCC considers the GNU __null value to be an integral constant expression.
10295 case Expr::SubstNonTypeTemplateParmExprClass:
10297 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
10299 case Expr::ParenExprClass:
10300 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
10301 case Expr::GenericSelectionExprClass:
10302 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
10303 case Expr::IntegerLiteralClass:
10304 case Expr::CharacterLiteralClass:
10305 case Expr::ObjCBoolLiteralExprClass:
10306 case Expr::CXXBoolLiteralExprClass:
10307 case Expr::CXXScalarValueInitExprClass:
10308 case Expr::TypeTraitExprClass:
10309 case Expr::ArrayTypeTraitExprClass:
10310 case Expr::ExpressionTraitExprClass:
10311 case Expr::CXXNoexceptExprClass:
10313 case Expr::CallExprClass:
10314 case Expr::CXXOperatorCallExprClass: {
10315 // C99 6.6/3 allows function calls within unevaluated subexpressions of
10316 // constant expressions, but they can never be ICEs because an ICE cannot
10317 // contain an operand of (pointer to) function type.
10318 const CallExpr *CE = cast<CallExpr>(E);
10319 if (CE->getBuiltinCallee())
10320 return CheckEvalInICE(E, Ctx);
10321 return ICEDiag(IK_NotICE, E->getLocStart());
10323 case Expr::DeclRefExprClass: {
10324 if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl()))
10326 const ValueDecl *D = dyn_cast<ValueDecl>(cast<DeclRefExpr>(E)->getDecl());
10327 if (Ctx.getLangOpts().CPlusPlus &&
10328 D && IsConstNonVolatile(D->getType())) {
10329 // Parameter variables are never constants. Without this check,
10330 // getAnyInitializer() can find a default argument, which leads
10332 if (isa<ParmVarDecl>(D))
10333 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10336 // A variable of non-volatile const-qualified integral or enumeration
10337 // type initialized by an ICE can be used in ICEs.
10338 if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) {
10339 if (!Dcl->getType()->isIntegralOrEnumerationType())
10340 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10343 // Look for a declaration of this variable that has an initializer, and
10344 // check whether it is an ICE.
10345 if (Dcl->getAnyInitializer(VD) && VD->checkInitIsICE())
10348 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10351 return ICEDiag(IK_NotICE, E->getLocStart());
10353 case Expr::UnaryOperatorClass: {
10354 const UnaryOperator *Exp = cast<UnaryOperator>(E);
10355 switch (Exp->getOpcode()) {
10363 // C99 6.6/3 allows increment and decrement within unevaluated
10364 // subexpressions of constant expressions, but they can never be ICEs
10365 // because an ICE cannot contain an lvalue operand.
10366 return ICEDiag(IK_NotICE, E->getLocStart());
10374 return CheckICE(Exp->getSubExpr(), Ctx);
10377 // OffsetOf falls through here.
10380 case Expr::OffsetOfExprClass: {
10381 // Note that per C99, offsetof must be an ICE. And AFAIK, using
10382 // EvaluateAsRValue matches the proposed gcc behavior for cases like
10383 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect
10384 // compliance: we should warn earlier for offsetof expressions with
10385 // array subscripts that aren't ICEs, and if the array subscripts
10386 // are ICEs, the value of the offsetof must be an integer constant.
10387 return CheckEvalInICE(E, Ctx);
10389 case Expr::UnaryExprOrTypeTraitExprClass: {
10390 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
10391 if ((Exp->getKind() == UETT_SizeOf) &&
10392 Exp->getTypeOfArgument()->isVariableArrayType())
10393 return ICEDiag(IK_NotICE, E->getLocStart());
10396 case Expr::BinaryOperatorClass: {
10397 const BinaryOperator *Exp = cast<BinaryOperator>(E);
10398 switch (Exp->getOpcode()) {
10412 // C99 6.6/3 allows assignments within unevaluated subexpressions of
10413 // constant expressions, but they can never be ICEs because an ICE cannot
10414 // contain an lvalue operand.
10415 return ICEDiag(IK_NotICE, E->getLocStart());
10434 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
10435 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
10436 if (Exp->getOpcode() == BO_Div ||
10437 Exp->getOpcode() == BO_Rem) {
10438 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
10439 // we don't evaluate one.
10440 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
10441 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
10443 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10444 if (REval.isSigned() && REval.isAllOnesValue()) {
10445 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
10446 if (LEval.isMinSignedValue())
10447 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10451 if (Exp->getOpcode() == BO_Comma) {
10452 if (Ctx.getLangOpts().C99) {
10453 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
10454 // if it isn't evaluated.
10455 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
10456 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10458 // In both C89 and C++, commas in ICEs are illegal.
10459 return ICEDiag(IK_NotICE, E->getLocStart());
10462 return Worst(LHSResult, RHSResult);
10466 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
10467 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
10468 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
10469 // Rare case where the RHS has a comma "side-effect"; we need
10470 // to actually check the condition to see whether the side
10471 // with the comma is evaluated.
10472 if ((Exp->getOpcode() == BO_LAnd) !=
10473 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
10478 return Worst(LHSResult, RHSResult);
10483 case Expr::ImplicitCastExprClass:
10484 case Expr::CStyleCastExprClass:
10485 case Expr::CXXFunctionalCastExprClass:
10486 case Expr::CXXStaticCastExprClass:
10487 case Expr::CXXReinterpretCastExprClass:
10488 case Expr::CXXConstCastExprClass:
10489 case Expr::ObjCBridgedCastExprClass: {
10490 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
10491 if (isa<ExplicitCastExpr>(E)) {
10492 if (const FloatingLiteral *FL
10493 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
10494 unsigned DestWidth = Ctx.getIntWidth(E->getType());
10495 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
10496 APSInt IgnoredVal(DestWidth, !DestSigned);
10498 // If the value does not fit in the destination type, the behavior is
10499 // undefined, so we are not required to treat it as a constant
10501 if (FL->getValue().convertToInteger(IgnoredVal,
10502 llvm::APFloat::rmTowardZero,
10503 &Ignored) & APFloat::opInvalidOp)
10504 return ICEDiag(IK_NotICE, E->getLocStart());
10508 switch (cast<CastExpr>(E)->getCastKind()) {
10509 case CK_LValueToRValue:
10510 case CK_AtomicToNonAtomic:
10511 case CK_NonAtomicToAtomic:
10513 case CK_IntegralToBoolean:
10514 case CK_IntegralCast:
10515 return CheckICE(SubExpr, Ctx);
10517 return ICEDiag(IK_NotICE, E->getLocStart());
10520 case Expr::BinaryConditionalOperatorClass: {
10521 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
10522 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
10523 if (CommonResult.Kind == IK_NotICE) return CommonResult;
10524 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
10525 if (FalseResult.Kind == IK_NotICE) return FalseResult;
10526 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
10527 if (FalseResult.Kind == IK_ICEIfUnevaluated &&
10528 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
10529 return FalseResult;
10531 case Expr::ConditionalOperatorClass: {
10532 const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
10533 // If the condition (ignoring parens) is a __builtin_constant_p call,
10534 // then only the true side is actually considered in an integer constant
10535 // expression, and it is fully evaluated. This is an important GNU
10536 // extension. See GCC PR38377 for discussion.
10537 if (const CallExpr *CallCE
10538 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
10539 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
10540 return CheckEvalInICE(E, Ctx);
10541 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
10542 if (CondResult.Kind == IK_NotICE)
10545 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
10546 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
10548 if (TrueResult.Kind == IK_NotICE)
10550 if (FalseResult.Kind == IK_NotICE)
10551 return FalseResult;
10552 if (CondResult.Kind == IK_ICEIfUnevaluated)
10554 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
10556 // Rare case where the diagnostics depend on which side is evaluated
10557 // Note that if we get here, CondResult is 0, and at least one of
10558 // TrueResult and FalseResult is non-zero.
10559 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
10560 return FalseResult;
10563 case Expr::CXXDefaultArgExprClass:
10564 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
10565 case Expr::CXXDefaultInitExprClass:
10566 return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx);
10567 case Expr::ChooseExprClass: {
10568 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
10572 llvm_unreachable("Invalid StmtClass!");
10575 /// Evaluate an expression as a C++11 integral constant expression.
10576 static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
10578 llvm::APSInt *Value,
10579 SourceLocation *Loc) {
10580 if (!E->getType()->isIntegralOrEnumerationType()) {
10581 if (Loc) *Loc = E->getExprLoc();
10586 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc))
10589 if (!Result.isInt()) {
10590 if (Loc) *Loc = E->getExprLoc();
10594 if (Value) *Value = Result.getInt();
10598 bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
10599 SourceLocation *Loc) const {
10600 if (Ctx.getLangOpts().CPlusPlus11)
10601 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc);
10603 ICEDiag D = CheckICE(this, Ctx);
10604 if (D.Kind != IK_ICE) {
10605 if (Loc) *Loc = D.Loc;
10611 bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, const ASTContext &Ctx,
10612 SourceLocation *Loc, bool isEvaluated) const {
10613 if (Ctx.getLangOpts().CPlusPlus11)
10614 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc);
10616 if (!isIntegerConstantExpr(Ctx, Loc))
10618 // The only possible side-effects here are due to UB discovered in the
10619 // evaluation (for instance, INT_MAX + 1). In such a case, we are still
10620 // required to treat the expression as an ICE, so we produce the folded
10622 if (!EvaluateAsInt(Value, Ctx, SE_AllowSideEffects))
10623 llvm_unreachable("ICE cannot be evaluated!");
10627 bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
10628 return CheckICE(this, Ctx).Kind == IK_ICE;
10631 bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
10632 SourceLocation *Loc) const {
10633 // We support this checking in C++98 mode in order to diagnose compatibility
10635 assert(Ctx.getLangOpts().CPlusPlus);
10637 // Build evaluation settings.
10638 Expr::EvalStatus Status;
10639 SmallVector<PartialDiagnosticAt, 8> Diags;
10640 Status.Diag = &Diags;
10641 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
10644 bool IsConstExpr = ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch);
10646 if (!Diags.empty()) {
10647 IsConstExpr = false;
10648 if (Loc) *Loc = Diags[0].first;
10649 } else if (!IsConstExpr) {
10650 // FIXME: This shouldn't happen.
10651 if (Loc) *Loc = getExprLoc();
10654 return IsConstExpr;
10657 bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
10658 const FunctionDecl *Callee,
10659 ArrayRef<const Expr*> Args,
10660 const Expr *This) const {
10661 Expr::EvalStatus Status;
10662 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
10665 const LValue *ThisPtr = nullptr;
10668 auto *MD = dyn_cast<CXXMethodDecl>(Callee);
10669 assert(MD && "Don't provide `this` for non-methods.");
10670 assert(!MD->isStatic() && "Don't provide `this` for static methods.");
10672 if (EvaluateObjectArgument(Info, This, ThisVal))
10673 ThisPtr = &ThisVal;
10674 if (Info.EvalStatus.HasSideEffects)
10678 ArgVector ArgValues(Args.size());
10679 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
10681 if ((*I)->isValueDependent() ||
10682 !Evaluate(ArgValues[I - Args.begin()], Info, *I))
10683 // If evaluation fails, throw away the argument entirely.
10684 ArgValues[I - Args.begin()] = APValue();
10685 if (Info.EvalStatus.HasSideEffects)
10689 // Build fake call to Callee.
10690 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr,
10692 return Evaluate(Value, Info, this) && !Info.EvalStatus.HasSideEffects;
10695 bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
10697 PartialDiagnosticAt> &Diags) {
10698 // FIXME: It would be useful to check constexpr function templates, but at the
10699 // moment the constant expression evaluator cannot cope with the non-rigorous
10700 // ASTs which we build for dependent expressions.
10701 if (FD->isDependentContext())
10704 Expr::EvalStatus Status;
10705 Status.Diag = &Diags;
10707 EvalInfo Info(FD->getASTContext(), Status,
10708 EvalInfo::EM_PotentialConstantExpression);
10710 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
10711 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;
10713 // Fabricate an arbitrary expression on the stack and pretend that it
10714 // is a temporary being used as the 'this' pointer.
10716 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
10717 This.set(&VIE, Info.CurrentCall->Index);
10719 ArrayRef<const Expr*> Args;
10722 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
10723 // Evaluate the call as a constant initializer, to allow the construction
10724 // of objects of non-literal types.
10725 Info.setEvaluatingDecl(This.getLValueBase(), Scratch);
10726 HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch);
10728 SourceLocation Loc = FD->getLocation();
10729 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : nullptr,
10730 Args, FD->getBody(), Info, Scratch, nullptr);
10733 return Diags.empty();
10736 bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
10737 const FunctionDecl *FD,
10739 PartialDiagnosticAt> &Diags) {
10740 Expr::EvalStatus Status;
10741 Status.Diag = &Diags;
10743 EvalInfo Info(FD->getASTContext(), Status,
10744 EvalInfo::EM_PotentialConstantExpressionUnevaluated);
10746 // Fabricate a call stack frame to give the arguments a plausible cover story.
10747 ArrayRef<const Expr*> Args;
10748 ArgVector ArgValues(0);
10749 bool Success = EvaluateArgs(Args, ArgValues, Info);
10752 "Failed to set up arguments for potential constant evaluation");
10753 CallStackFrame Frame(Info, SourceLocation(), FD, nullptr, ArgValues.data());
10755 APValue ResultScratch;
10756 Evaluate(ResultScratch, Info, E);
10757 return Diags.empty();
10760 bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
10761 unsigned Type) const {
10762 if (!getType()->isPointerType())
10765 Expr::EvalStatus Status;
10766 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
10767 return tryEvaluateBuiltinObjectSize(this, Type, Info, Result);