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.
739 case EM_ConstantExpression:
740 case EM_PotentialConstantExpression:
741 case EM_ConstantExpressionUnevaluated:
742 case EM_PotentialConstantExpressionUnevaluated:
744 HasActiveDiagnostic = false;
745 return OptionalDiagnostic();
749 unsigned CallStackNotes = CallStackDepth - 1;
750 unsigned Limit = Ctx.getDiagnostics().getConstexprBacktraceLimit();
752 CallStackNotes = std::min(CallStackNotes, Limit + 1);
753 if (checkingPotentialConstantExpression())
756 HasActiveDiagnostic = true;
757 HasFoldFailureDiagnostic = !IsCCEDiag;
758 EvalStatus.Diag->clear();
759 EvalStatus.Diag->reserve(1 + ExtraNotes + CallStackNotes);
760 addDiag(Loc, DiagId);
761 if (!checkingPotentialConstantExpression())
763 return OptionalDiagnostic(&(*EvalStatus.Diag)[0].second);
765 HasActiveDiagnostic = false;
766 return OptionalDiagnostic();
769 // Diagnose that the evaluation could not be folded (FF => FoldFailure)
771 FFDiag(SourceLocation Loc,
772 diag::kind DiagId = diag::note_invalid_subexpr_in_const_expr,
773 unsigned ExtraNotes = 0) {
774 return Diag(Loc, DiagId, ExtraNotes, false);
777 OptionalDiagnostic FFDiag(const Expr *E, diag::kind DiagId
778 = diag::note_invalid_subexpr_in_const_expr,
779 unsigned ExtraNotes = 0) {
781 return Diag(E->getExprLoc(), DiagId, ExtraNotes, /*IsCCEDiag*/false);
782 HasActiveDiagnostic = false;
783 return OptionalDiagnostic();
786 /// Diagnose that the evaluation does not produce a C++11 core constant
789 /// FIXME: Stop evaluating if we're in EM_ConstantExpression or
790 /// EM_PotentialConstantExpression mode and we produce one of these.
791 OptionalDiagnostic CCEDiag(SourceLocation Loc, diag::kind DiagId
792 = diag::note_invalid_subexpr_in_const_expr,
793 unsigned ExtraNotes = 0) {
794 // Don't override a previous diagnostic. Don't bother collecting
795 // diagnostics if we're evaluating for overflow.
796 if (!EvalStatus.Diag || !EvalStatus.Diag->empty()) {
797 HasActiveDiagnostic = false;
798 return OptionalDiagnostic();
800 return Diag(Loc, DiagId, ExtraNotes, true);
802 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind DiagId
803 = diag::note_invalid_subexpr_in_const_expr,
804 unsigned ExtraNotes = 0) {
805 return CCEDiag(E->getExprLoc(), DiagId, ExtraNotes);
807 /// Add a note to a prior diagnostic.
808 OptionalDiagnostic Note(SourceLocation Loc, diag::kind DiagId) {
809 if (!HasActiveDiagnostic)
810 return OptionalDiagnostic();
811 return OptionalDiagnostic(&addDiag(Loc, DiagId));
814 /// Add a stack of notes to a prior diagnostic.
815 void addNotes(ArrayRef<PartialDiagnosticAt> Diags) {
816 if (HasActiveDiagnostic) {
817 EvalStatus.Diag->insert(EvalStatus.Diag->end(),
818 Diags.begin(), Diags.end());
822 /// Should we continue evaluation after encountering a side-effect that we
824 bool keepEvaluatingAfterSideEffect() {
826 case EM_PotentialConstantExpression:
827 case EM_PotentialConstantExpressionUnevaluated:
828 case EM_EvaluateForOverflow:
829 case EM_IgnoreSideEffects:
832 case EM_ConstantExpression:
833 case EM_ConstantExpressionUnevaluated:
834 case EM_ConstantFold:
838 llvm_unreachable("Missed EvalMode case");
841 /// Note that we have had a side-effect, and determine whether we should
843 bool noteSideEffect() {
844 EvalStatus.HasSideEffects = true;
845 return keepEvaluatingAfterSideEffect();
848 /// Should we continue evaluation after encountering undefined behavior?
849 bool keepEvaluatingAfterUndefinedBehavior() {
851 case EM_EvaluateForOverflow:
852 case EM_IgnoreSideEffects:
853 case EM_ConstantFold:
857 case EM_PotentialConstantExpression:
858 case EM_PotentialConstantExpressionUnevaluated:
859 case EM_ConstantExpression:
860 case EM_ConstantExpressionUnevaluated:
863 llvm_unreachable("Missed EvalMode case");
866 /// Note that we hit something that was technically undefined behavior, but
867 /// that we can evaluate past it (such as signed overflow or floating-point
868 /// division by zero.)
869 bool noteUndefinedBehavior() {
870 EvalStatus.HasUndefinedBehavior = true;
871 return keepEvaluatingAfterUndefinedBehavior();
874 /// Should we continue evaluation as much as possible after encountering a
875 /// construct which can't be reduced to a value?
876 bool keepEvaluatingAfterFailure() {
881 case EM_PotentialConstantExpression:
882 case EM_PotentialConstantExpressionUnevaluated:
883 case EM_EvaluateForOverflow:
886 case EM_ConstantExpression:
887 case EM_ConstantExpressionUnevaluated:
888 case EM_ConstantFold:
889 case EM_IgnoreSideEffects:
893 llvm_unreachable("Missed EvalMode case");
896 /// Notes that we failed to evaluate an expression that other expressions
897 /// directly depend on, and determine if we should keep evaluating. This
898 /// should only be called if we actually intend to keep evaluating.
900 /// Call noteSideEffect() instead if we may be able to ignore the value that
901 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
903 /// (Foo(), 1) // use noteSideEffect
904 /// (Foo() || true) // use noteSideEffect
905 /// Foo() + 1 // use noteFailure
906 LLVM_NODISCARD bool noteFailure() {
907 // Failure when evaluating some expression often means there is some
908 // subexpression whose evaluation was skipped. Therefore, (because we
909 // don't track whether we skipped an expression when unwinding after an
910 // evaluation failure) every evaluation failure that bubbles up from a
911 // subexpression implies that a side-effect has potentially happened. We
912 // skip setting the HasSideEffects flag to true until we decide to
913 // continue evaluating after that point, which happens here.
914 bool KeepGoing = keepEvaluatingAfterFailure();
915 EvalStatus.HasSideEffects |= KeepGoing;
919 class ArrayInitLoopIndex {
924 ArrayInitLoopIndex(EvalInfo &Info)
925 : Info(Info), OuterIndex(Info.ArrayInitIndex) {
926 Info.ArrayInitIndex = 0;
928 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
930 operator uint64_t&() { return Info.ArrayInitIndex; }
934 /// Object used to treat all foldable expressions as constant expressions.
935 struct FoldConstant {
938 bool HadNoPriorDiags;
939 EvalInfo::EvaluationMode OldMode;
941 explicit FoldConstant(EvalInfo &Info, bool Enabled)
944 HadNoPriorDiags(Info.EvalStatus.Diag &&
945 Info.EvalStatus.Diag->empty() &&
946 !Info.EvalStatus.HasSideEffects),
947 OldMode(Info.EvalMode) {
949 (Info.EvalMode == EvalInfo::EM_ConstantExpression ||
950 Info.EvalMode == EvalInfo::EM_ConstantExpressionUnevaluated))
951 Info.EvalMode = EvalInfo::EM_ConstantFold;
953 void keepDiagnostics() { Enabled = false; }
955 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
956 !Info.EvalStatus.HasSideEffects)
957 Info.EvalStatus.Diag->clear();
958 Info.EvalMode = OldMode;
962 /// RAII object used to treat the current evaluation as the correct pointer
963 /// offset fold for the current EvalMode
964 struct FoldOffsetRAII {
966 EvalInfo::EvaluationMode OldMode;
967 explicit FoldOffsetRAII(EvalInfo &Info)
968 : Info(Info), OldMode(Info.EvalMode) {
969 if (!Info.checkingPotentialConstantExpression())
970 Info.EvalMode = EvalInfo::EM_OffsetFold;
973 ~FoldOffsetRAII() { Info.EvalMode = OldMode; }
976 /// RAII object used to optionally suppress diagnostics and side-effects from
977 /// a speculative evaluation.
978 class SpeculativeEvaluationRAII {
979 /// Pair of EvalInfo, and a bit that stores whether or not we were
980 /// speculatively evaluating when we created this RAII.
981 llvm::PointerIntPair<EvalInfo *, 1, bool> InfoAndOldSpecEval;
982 Expr::EvalStatus Old;
984 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
985 InfoAndOldSpecEval = Other.InfoAndOldSpecEval;
987 Other.InfoAndOldSpecEval.setPointer(nullptr);
990 void maybeRestoreState() {
991 EvalInfo *Info = InfoAndOldSpecEval.getPointer();
995 Info->EvalStatus = Old;
996 Info->IsSpeculativelyEvaluating = InfoAndOldSpecEval.getInt();
1000 SpeculativeEvaluationRAII() = default;
1002 SpeculativeEvaluationRAII(
1003 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
1004 : InfoAndOldSpecEval(&Info, Info.IsSpeculativelyEvaluating),
1005 Old(Info.EvalStatus) {
1006 Info.EvalStatus.Diag = NewDiag;
1007 Info.IsSpeculativelyEvaluating = true;
1010 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
1011 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
1012 moveFromAndCancel(std::move(Other));
1015 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
1016 maybeRestoreState();
1017 moveFromAndCancel(std::move(Other));
1021 ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1024 /// RAII object wrapping a full-expression or block scope, and handling
1025 /// the ending of the lifetime of temporaries created within it.
1026 template<bool IsFullExpression>
1029 unsigned OldStackSize;
1031 ScopeRAII(EvalInfo &Info)
1032 : Info(Info), OldStackSize(Info.CleanupStack.size()) {}
1034 // Body moved to a static method to encourage the compiler to inline away
1035 // instances of this class.
1036 cleanup(Info, OldStackSize);
1039 static void cleanup(EvalInfo &Info, unsigned OldStackSize) {
1040 unsigned NewEnd = OldStackSize;
1041 for (unsigned I = OldStackSize, N = Info.CleanupStack.size();
1043 if (IsFullExpression && Info.CleanupStack[I].isLifetimeExtended()) {
1044 // Full-expression cleanup of a lifetime-extended temporary: nothing
1045 // to do, just move this cleanup to the right place in the stack.
1046 std::swap(Info.CleanupStack[I], Info.CleanupStack[NewEnd]);
1049 // End the lifetime of the object.
1050 Info.CleanupStack[I].endLifetime();
1053 Info.CleanupStack.erase(Info.CleanupStack.begin() + NewEnd,
1054 Info.CleanupStack.end());
1057 typedef ScopeRAII<false> BlockScopeRAII;
1058 typedef ScopeRAII<true> FullExpressionRAII;
1061 bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1062 CheckSubobjectKind CSK) {
1065 if (isOnePastTheEnd()) {
1066 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
1074 void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1077 // If we're complaining, we must be able to statically determine the size of
1078 // the most derived array.
1079 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1080 Info.CCEDiag(E, diag::note_constexpr_array_index)
1082 << static_cast<unsigned>(getMostDerivedArraySize());
1084 Info.CCEDiag(E, diag::note_constexpr_array_index)
1085 << N << /*non-array*/ 1;
1089 CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
1090 const FunctionDecl *Callee, const LValue *This,
1092 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1093 Arguments(Arguments), CallLoc(CallLoc), Index(Info.NextCallIndex++) {
1094 Info.CurrentCall = this;
1095 ++Info.CallStackDepth;
1098 CallStackFrame::~CallStackFrame() {
1099 assert(Info.CurrentCall == this && "calls retired out of order");
1100 --Info.CallStackDepth;
1101 Info.CurrentCall = Caller;
1104 APValue &CallStackFrame::createTemporary(const void *Key,
1105 bool IsLifetimeExtended) {
1106 APValue &Result = Temporaries[Key];
1107 assert(Result.isUninit() && "temporary created multiple times");
1108 Info.CleanupStack.push_back(Cleanup(&Result, IsLifetimeExtended));
1112 static void describeCall(CallStackFrame *Frame, raw_ostream &Out);
1114 void EvalInfo::addCallStack(unsigned Limit) {
1115 // Determine which calls to skip, if any.
1116 unsigned ActiveCalls = CallStackDepth - 1;
1117 unsigned SkipStart = ActiveCalls, SkipEnd = SkipStart;
1118 if (Limit && Limit < ActiveCalls) {
1119 SkipStart = Limit / 2 + Limit % 2;
1120 SkipEnd = ActiveCalls - Limit / 2;
1123 // Walk the call stack and add the diagnostics.
1124 unsigned CallIdx = 0;
1125 for (CallStackFrame *Frame = CurrentCall; Frame != &BottomFrame;
1126 Frame = Frame->Caller, ++CallIdx) {
1128 if (CallIdx >= SkipStart && CallIdx < SkipEnd) {
1129 if (CallIdx == SkipStart) {
1130 // Note that we're skipping calls.
1131 addDiag(Frame->CallLoc, diag::note_constexpr_calls_suppressed)
1132 << unsigned(ActiveCalls - Limit);
1137 // Use a different note for an inheriting constructor, because from the
1138 // user's perspective it's not really a function at all.
1139 if (auto *CD = dyn_cast_or_null<CXXConstructorDecl>(Frame->Callee)) {
1140 if (CD->isInheritingConstructor()) {
1141 addDiag(Frame->CallLoc, diag::note_constexpr_inherited_ctor_call_here)
1147 SmallVector<char, 128> Buffer;
1148 llvm::raw_svector_ostream Out(Buffer);
1149 describeCall(Frame, Out);
1150 addDiag(Frame->CallLoc, diag::note_constexpr_call_here) << Out.str();
1155 struct ComplexValue {
1160 APSInt IntReal, IntImag;
1161 APFloat FloatReal, FloatImag;
1163 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1165 void makeComplexFloat() { IsInt = false; }
1166 bool isComplexFloat() const { return !IsInt; }
1167 APFloat &getComplexFloatReal() { return FloatReal; }
1168 APFloat &getComplexFloatImag() { return FloatImag; }
1170 void makeComplexInt() { IsInt = true; }
1171 bool isComplexInt() const { return IsInt; }
1172 APSInt &getComplexIntReal() { return IntReal; }
1173 APSInt &getComplexIntImag() { return IntImag; }
1175 void moveInto(APValue &v) const {
1176 if (isComplexFloat())
1177 v = APValue(FloatReal, FloatImag);
1179 v = APValue(IntReal, IntImag);
1181 void setFrom(const APValue &v) {
1182 assert(v.isComplexFloat() || v.isComplexInt());
1183 if (v.isComplexFloat()) {
1185 FloatReal = v.getComplexFloatReal();
1186 FloatImag = v.getComplexFloatImag();
1189 IntReal = v.getComplexIntReal();
1190 IntImag = v.getComplexIntImag();
1196 APValue::LValueBase Base;
1198 unsigned InvalidBase : 1;
1199 unsigned CallIndex : 31;
1200 SubobjectDesignator Designator;
1203 const APValue::LValueBase getLValueBase() const { return Base; }
1204 CharUnits &getLValueOffset() { return Offset; }
1205 const CharUnits &getLValueOffset() const { return Offset; }
1206 unsigned getLValueCallIndex() const { return CallIndex; }
1207 SubobjectDesignator &getLValueDesignator() { return Designator; }
1208 const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1209 bool isNullPointer() const { return IsNullPtr;}
1211 void moveInto(APValue &V) const {
1212 if (Designator.Invalid)
1213 V = APValue(Base, Offset, APValue::NoLValuePath(), CallIndex,
1216 assert(!InvalidBase && "APValues can't handle invalid LValue bases");
1217 assert(!Designator.FirstEntryIsAnUnsizedArray &&
1218 "Unsized array with a valid base?");
1219 V = APValue(Base, Offset, Designator.Entries,
1220 Designator.IsOnePastTheEnd, CallIndex, IsNullPtr);
1223 void setFrom(ASTContext &Ctx, const APValue &V) {
1224 assert(V.isLValue() && "Setting LValue from a non-LValue?");
1225 Base = V.getLValueBase();
1226 Offset = V.getLValueOffset();
1227 InvalidBase = false;
1228 CallIndex = V.getLValueCallIndex();
1229 Designator = SubobjectDesignator(Ctx, V);
1230 IsNullPtr = V.isNullPointer();
1233 void set(APValue::LValueBase B, unsigned I = 0, bool BInvalid = false,
1234 bool IsNullPtr_ = false, uint64_t Offset_ = 0) {
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(Offset_);
1246 InvalidBase = BInvalid;
1248 Designator = SubobjectDesignator(getType(B));
1249 IsNullPtr = IsNullPtr_;
1252 void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1256 // Check that this LValue is not based on a null pointer. If it is, produce
1257 // a diagnostic and mark the designator as invalid.
1258 bool checkNullPointer(EvalInfo &Info, const Expr *E,
1259 CheckSubobjectKind CSK) {
1260 if (Designator.Invalid)
1263 Info.CCEDiag(E, diag::note_constexpr_null_subobject)
1265 Designator.setInvalid();
1271 // Check this LValue refers to an object. If not, set the designator to be
1272 // invalid and emit a diagnostic.
1273 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1274 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1275 Designator.checkSubobject(Info, E, CSK);
1278 void addDecl(EvalInfo &Info, const Expr *E,
1279 const Decl *D, bool Virtual = false) {
1280 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
1281 Designator.addDeclUnchecked(D, Virtual);
1283 void addUnsizedArray(EvalInfo &Info, QualType ElemTy) {
1284 assert(Designator.Entries.empty() && getType(Base)->isPointerType());
1285 assert(isBaseAnAllocSizeCall(Base) &&
1286 "Only alloc_size bases can have unsized arrays");
1287 Designator.FirstEntryIsAnUnsizedArray = true;
1288 Designator.addUnsizedArrayUnchecked(ElemTy);
1290 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1291 if (checkSubobject(Info, E, CSK_ArrayToPointer))
1292 Designator.addArrayUnchecked(CAT);
1294 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1295 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
1296 Designator.addComplexUnchecked(EltTy, Imag);
1298 void clearIsNullPointer() {
1301 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E,
1302 const APSInt &Index, CharUnits ElementSize) {
1303 // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB,
1304 // but we're not required to diagnose it and it's valid in C++.)
1308 // Compute the new offset in the appropriate width, wrapping at 64 bits.
1309 // FIXME: When compiling for a 32-bit target, we should use 32-bit
1311 uint64_t Offset64 = Offset.getQuantity();
1312 uint64_t ElemSize64 = ElementSize.getQuantity();
1313 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
1314 Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64);
1316 if (checkNullPointer(Info, E, CSK_ArrayIndex))
1317 Designator.adjustIndex(Info, E, Index);
1318 clearIsNullPointer();
1320 void adjustOffset(CharUnits N) {
1322 if (N.getQuantity())
1323 clearIsNullPointer();
1329 explicit MemberPtr(const ValueDecl *Decl) :
1330 DeclAndIsDerivedMember(Decl, false), Path() {}
1332 /// The member or (direct or indirect) field referred to by this member
1333 /// pointer, or 0 if this is a null member pointer.
1334 const ValueDecl *getDecl() const {
1335 return DeclAndIsDerivedMember.getPointer();
1337 /// Is this actually a member of some type derived from the relevant class?
1338 bool isDerivedMember() const {
1339 return DeclAndIsDerivedMember.getInt();
1341 /// Get the class which the declaration actually lives in.
1342 const CXXRecordDecl *getContainingRecord() const {
1343 return cast<CXXRecordDecl>(
1344 DeclAndIsDerivedMember.getPointer()->getDeclContext());
1347 void moveInto(APValue &V) const {
1348 V = APValue(getDecl(), isDerivedMember(), Path);
1350 void setFrom(const APValue &V) {
1351 assert(V.isMemberPointer());
1352 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1353 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1355 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
1356 Path.insert(Path.end(), P.begin(), P.end());
1359 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1360 /// whether the member is a member of some class derived from the class type
1361 /// of the member pointer.
1362 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1363 /// Path - The path of base/derived classes from the member declaration's
1364 /// class (exclusive) to the class type of the member pointer (inclusive).
1365 SmallVector<const CXXRecordDecl*, 4> Path;
1367 /// Perform a cast towards the class of the Decl (either up or down the
1369 bool castBack(const CXXRecordDecl *Class) {
1370 assert(!Path.empty());
1371 const CXXRecordDecl *Expected;
1372 if (Path.size() >= 2)
1373 Expected = Path[Path.size() - 2];
1375 Expected = getContainingRecord();
1376 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1377 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1378 // if B does not contain the original member and is not a base or
1379 // derived class of the class containing the original member, the result
1380 // of the cast is undefined.
1381 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1382 // (D::*). We consider that to be a language defect.
1388 /// Perform a base-to-derived member pointer cast.
1389 bool castToDerived(const CXXRecordDecl *Derived) {
1392 if (!isDerivedMember()) {
1393 Path.push_back(Derived);
1396 if (!castBack(Derived))
1399 DeclAndIsDerivedMember.setInt(false);
1402 /// Perform a derived-to-base member pointer cast.
1403 bool castToBase(const CXXRecordDecl *Base) {
1407 DeclAndIsDerivedMember.setInt(true);
1408 if (isDerivedMember()) {
1409 Path.push_back(Base);
1412 return castBack(Base);
1416 /// Compare two member pointers, which are assumed to be of the same type.
1417 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1418 if (!LHS.getDecl() || !RHS.getDecl())
1419 return !LHS.getDecl() && !RHS.getDecl();
1420 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1422 return LHS.Path == RHS.Path;
1426 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1427 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1428 const LValue &This, const Expr *E,
1429 bool AllowNonLiteralTypes = false);
1430 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
1431 bool InvalidBaseOK = false);
1432 static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
1433 bool InvalidBaseOK = false);
1434 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1436 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1437 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1438 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1440 static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1441 static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1442 static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
1444 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1446 //===----------------------------------------------------------------------===//
1448 //===----------------------------------------------------------------------===//
1450 /// Negate an APSInt in place, converting it to a signed form if necessary, and
1451 /// preserving its value (by extending by up to one bit as needed).
1452 static void negateAsSigned(APSInt &Int) {
1453 if (Int.isUnsigned() || Int.isMinSignedValue()) {
1454 Int = Int.extend(Int.getBitWidth() + 1);
1455 Int.setIsSigned(true);
1460 /// Produce a string describing the given constexpr call.
1461 static void describeCall(CallStackFrame *Frame, raw_ostream &Out) {
1462 unsigned ArgIndex = 0;
1463 bool IsMemberCall = isa<CXXMethodDecl>(Frame->Callee) &&
1464 !isa<CXXConstructorDecl>(Frame->Callee) &&
1465 cast<CXXMethodDecl>(Frame->Callee)->isInstance();
1468 Out << *Frame->Callee << '(';
1470 if (Frame->This && IsMemberCall) {
1472 Frame->This->moveInto(Val);
1473 Val.printPretty(Out, Frame->Info.Ctx,
1474 Frame->This->Designator.MostDerivedType);
1475 // FIXME: Add parens around Val if needed.
1476 Out << "->" << *Frame->Callee << '(';
1477 IsMemberCall = false;
1480 for (FunctionDecl::param_const_iterator I = Frame->Callee->param_begin(),
1481 E = Frame->Callee->param_end(); I != E; ++I, ++ArgIndex) {
1482 if (ArgIndex > (unsigned)IsMemberCall)
1485 const ParmVarDecl *Param = *I;
1486 const APValue &Arg = Frame->Arguments[ArgIndex];
1487 Arg.printPretty(Out, Frame->Info.Ctx, Param->getType());
1489 if (ArgIndex == 0 && IsMemberCall)
1490 Out << "->" << *Frame->Callee << '(';
1496 /// Evaluate an expression to see if it had side-effects, and discard its
1498 /// \return \c true if the caller should keep evaluating.
1499 static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
1501 if (!Evaluate(Scratch, Info, E))
1502 // We don't need the value, but we might have skipped a side effect here.
1503 return Info.noteSideEffect();
1507 /// Should this call expression be treated as a string literal?
1508 static bool IsStringLiteralCall(const CallExpr *E) {
1509 unsigned Builtin = E->getBuiltinCallee();
1510 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
1511 Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
1514 static bool IsGlobalLValue(APValue::LValueBase B) {
1515 // C++11 [expr.const]p3 An address constant expression is a prvalue core
1516 // constant expression of pointer type that evaluates to...
1518 // ... a null pointer value, or a prvalue core constant expression of type
1520 if (!B) return true;
1522 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
1523 // ... the address of an object with static storage duration,
1524 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
1525 return VD->hasGlobalStorage();
1526 // ... the address of a function,
1527 return isa<FunctionDecl>(D);
1530 const Expr *E = B.get<const Expr*>();
1531 switch (E->getStmtClass()) {
1534 case Expr::CompoundLiteralExprClass: {
1535 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
1536 return CLE->isFileScope() && CLE->isLValue();
1538 case Expr::MaterializeTemporaryExprClass:
1539 // A materialized temporary might have been lifetime-extended to static
1540 // storage duration.
1541 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
1542 // A string literal has static storage duration.
1543 case Expr::StringLiteralClass:
1544 case Expr::PredefinedExprClass:
1545 case Expr::ObjCStringLiteralClass:
1546 case Expr::ObjCEncodeExprClass:
1547 case Expr::CXXTypeidExprClass:
1548 case Expr::CXXUuidofExprClass:
1550 case Expr::CallExprClass:
1551 return IsStringLiteralCall(cast<CallExpr>(E));
1552 // For GCC compatibility, &&label has static storage duration.
1553 case Expr::AddrLabelExprClass:
1555 // A Block literal expression may be used as the initialization value for
1556 // Block variables at global or local static scope.
1557 case Expr::BlockExprClass:
1558 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
1559 case Expr::ImplicitValueInitExprClass:
1561 // We can never form an lvalue with an implicit value initialization as its
1562 // base through expression evaluation, so these only appear in one case: the
1563 // implicit variable declaration we invent when checking whether a constexpr
1564 // constructor can produce a constant expression. We must assume that such
1565 // an expression might be a global lvalue.
1570 static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
1571 assert(Base && "no location for a null lvalue");
1572 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1574 Info.Note(VD->getLocation(), diag::note_declared_at);
1576 Info.Note(Base.get<const Expr*>()->getExprLoc(),
1577 diag::note_constexpr_temporary_here);
1580 /// Check that this reference or pointer core constant expression is a valid
1581 /// value for an address or reference constant expression. Return true if we
1582 /// can fold this expression, whether or not it's a constant expression.
1583 static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
1584 QualType Type, const LValue &LVal) {
1585 bool IsReferenceType = Type->isReferenceType();
1587 APValue::LValueBase Base = LVal.getLValueBase();
1588 const SubobjectDesignator &Designator = LVal.getLValueDesignator();
1590 // Check that the object is a global. Note that the fake 'this' object we
1591 // manufacture when checking potential constant expressions is conservatively
1592 // assumed to be global here.
1593 if (!IsGlobalLValue(Base)) {
1594 if (Info.getLangOpts().CPlusPlus11) {
1595 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1596 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
1597 << IsReferenceType << !Designator.Entries.empty()
1599 NoteLValueLocation(Info, Base);
1603 // Don't allow references to temporaries to escape.
1606 assert((Info.checkingPotentialConstantExpression() ||
1607 LVal.getLValueCallIndex() == 0) &&
1608 "have call index for global lvalue");
1610 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
1611 if (const VarDecl *Var = dyn_cast<const VarDecl>(VD)) {
1612 // Check if this is a thread-local variable.
1613 if (Var->getTLSKind())
1616 // A dllimport variable never acts like a constant.
1617 if (Var->hasAttr<DLLImportAttr>())
1620 if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) {
1621 // __declspec(dllimport) must be handled very carefully:
1622 // We must never initialize an expression with the thunk in C++.
1623 // Doing otherwise would allow the same id-expression to yield
1624 // different addresses for the same function in different translation
1625 // units. However, this means that we must dynamically initialize the
1626 // expression with the contents of the import address table at runtime.
1628 // The C language has no notion of ODR; furthermore, it has no notion of
1629 // dynamic initialization. This means that we are permitted to
1630 // perform initialization with the address of the thunk.
1631 if (Info.getLangOpts().CPlusPlus && FD->hasAttr<DLLImportAttr>())
1636 // Allow address constant expressions to be past-the-end pointers. This is
1637 // an extension: the standard requires them to point to an object.
1638 if (!IsReferenceType)
1641 // A reference constant expression must refer to an object.
1643 // FIXME: diagnostic
1648 // Does this refer one past the end of some object?
1649 if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
1650 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1651 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
1652 << !Designator.Entries.empty() << !!VD << VD;
1653 NoteLValueLocation(Info, Base);
1659 /// Check that this core constant expression is of literal type, and if not,
1660 /// produce an appropriate diagnostic.
1661 static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
1662 const LValue *This = nullptr) {
1663 if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx))
1666 // C++1y: A constant initializer for an object o [...] may also invoke
1667 // constexpr constructors for o and its subobjects even if those objects
1668 // are of non-literal class types.
1670 // C++11 missed this detail for aggregates, so classes like this:
1671 // struct foo_t { union { int i; volatile int j; } u; };
1672 // are not (obviously) initializable like so:
1673 // __attribute__((__require_constant_initialization__))
1674 // static const foo_t x = {{0}};
1675 // because "i" is a subobject with non-literal initialization (due to the
1676 // volatile member of the union). See:
1677 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
1678 // Therefore, we use the C++1y behavior.
1679 if (This && Info.EvaluatingDecl == This->getLValueBase())
1682 // Prvalue constant expressions must be of literal types.
1683 if (Info.getLangOpts().CPlusPlus11)
1684 Info.FFDiag(E, diag::note_constexpr_nonliteral)
1687 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1691 /// Check that this core constant expression value is a valid value for a
1692 /// constant expression. If not, report an appropriate diagnostic. Does not
1693 /// check that the expression is of literal type.
1694 static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
1695 QualType Type, const APValue &Value) {
1696 if (Value.isUninit()) {
1697 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
1702 // We allow _Atomic(T) to be initialized from anything that T can be
1703 // initialized from.
1704 if (const AtomicType *AT = Type->getAs<AtomicType>())
1705 Type = AT->getValueType();
1707 // Core issue 1454: For a literal constant expression of array or class type,
1708 // each subobject of its value shall have been initialized by a constant
1710 if (Value.isArray()) {
1711 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
1712 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
1713 if (!CheckConstantExpression(Info, DiagLoc, EltTy,
1714 Value.getArrayInitializedElt(I)))
1717 if (!Value.hasArrayFiller())
1719 return CheckConstantExpression(Info, DiagLoc, EltTy,
1720 Value.getArrayFiller());
1722 if (Value.isUnion() && Value.getUnionField()) {
1723 return CheckConstantExpression(Info, DiagLoc,
1724 Value.getUnionField()->getType(),
1725 Value.getUnionValue());
1727 if (Value.isStruct()) {
1728 RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
1729 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
1730 unsigned BaseIndex = 0;
1731 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
1732 End = CD->bases_end(); I != End; ++I, ++BaseIndex) {
1733 if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
1734 Value.getStructBase(BaseIndex)))
1738 for (const auto *I : RD->fields()) {
1739 if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
1740 Value.getStructField(I->getFieldIndex())))
1745 if (Value.isLValue()) {
1747 LVal.setFrom(Info.Ctx, Value);
1748 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal);
1751 // Everything else is fine.
1755 static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
1756 return LVal.Base.dyn_cast<const ValueDecl*>();
1759 static bool IsLiteralLValue(const LValue &Value) {
1760 if (Value.CallIndex)
1762 const Expr *E = Value.Base.dyn_cast<const Expr*>();
1763 return E && !isa<MaterializeTemporaryExpr>(E);
1766 static bool IsWeakLValue(const LValue &Value) {
1767 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1768 return Decl && Decl->isWeak();
1771 static bool isZeroSized(const LValue &Value) {
1772 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1773 if (Decl && isa<VarDecl>(Decl)) {
1774 QualType Ty = Decl->getType();
1775 if (Ty->isArrayType())
1776 return Ty->isIncompleteType() ||
1777 Decl->getASTContext().getTypeSize(Ty) == 0;
1782 static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
1783 // A null base expression indicates a null pointer. These are always
1784 // evaluatable, and they are false unless the offset is zero.
1785 if (!Value.getLValueBase()) {
1786 Result = !Value.getLValueOffset().isZero();
1790 // We have a non-null base. These are generally known to be true, but if it's
1791 // a weak declaration it can be null at runtime.
1793 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
1794 return !Decl || !Decl->isWeak();
1797 static bool HandleConversionToBool(const APValue &Val, bool &Result) {
1798 switch (Val.getKind()) {
1799 case APValue::Uninitialized:
1802 Result = Val.getInt().getBoolValue();
1804 case APValue::Float:
1805 Result = !Val.getFloat().isZero();
1807 case APValue::ComplexInt:
1808 Result = Val.getComplexIntReal().getBoolValue() ||
1809 Val.getComplexIntImag().getBoolValue();
1811 case APValue::ComplexFloat:
1812 Result = !Val.getComplexFloatReal().isZero() ||
1813 !Val.getComplexFloatImag().isZero();
1815 case APValue::LValue:
1816 return EvalPointerValueAsBool(Val, Result);
1817 case APValue::MemberPointer:
1818 Result = Val.getMemberPointerDecl();
1820 case APValue::Vector:
1821 case APValue::Array:
1822 case APValue::Struct:
1823 case APValue::Union:
1824 case APValue::AddrLabelDiff:
1828 llvm_unreachable("unknown APValue kind");
1831 static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
1833 assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition");
1835 if (!Evaluate(Val, Info, E))
1837 return HandleConversionToBool(Val, Result);
1840 template<typename T>
1841 static bool HandleOverflow(EvalInfo &Info, const Expr *E,
1842 const T &SrcValue, QualType DestType) {
1843 Info.CCEDiag(E, diag::note_constexpr_overflow)
1844 << SrcValue << DestType;
1845 return Info.noteUndefinedBehavior();
1848 static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
1849 QualType SrcType, const APFloat &Value,
1850 QualType DestType, APSInt &Result) {
1851 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
1852 // Determine whether we are converting to unsigned or signed.
1853 bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
1855 Result = APSInt(DestWidth, !DestSigned);
1857 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
1858 & APFloat::opInvalidOp)
1859 return HandleOverflow(Info, E, Value, DestType);
1863 static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
1864 QualType SrcType, QualType DestType,
1866 APFloat Value = Result;
1868 if (Result.convert(Info.Ctx.getFloatTypeSemantics(DestType),
1869 APFloat::rmNearestTiesToEven, &ignored)
1870 & APFloat::opOverflow)
1871 return HandleOverflow(Info, E, Value, DestType);
1875 static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
1876 QualType DestType, QualType SrcType,
1877 const APSInt &Value) {
1878 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
1879 APSInt Result = Value;
1880 // Figure out if this is a truncate, extend or noop cast.
1881 // If the input is signed, do a sign extend, noop, or truncate.
1882 Result = Result.extOrTrunc(DestWidth);
1883 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
1887 static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
1888 QualType SrcType, const APSInt &Value,
1889 QualType DestType, APFloat &Result) {
1890 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
1891 if (Result.convertFromAPInt(Value, Value.isSigned(),
1892 APFloat::rmNearestTiesToEven)
1893 & APFloat::opOverflow)
1894 return HandleOverflow(Info, E, Value, DestType);
1898 static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
1899 APValue &Value, const FieldDecl *FD) {
1900 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield");
1902 if (!Value.isInt()) {
1903 // Trying to store a pointer-cast-to-integer into a bitfield.
1904 // FIXME: In this case, we should provide the diagnostic for casting
1905 // a pointer to an integer.
1906 assert(Value.isLValue() && "integral value neither int nor lvalue?");
1911 APSInt &Int = Value.getInt();
1912 unsigned OldBitWidth = Int.getBitWidth();
1913 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx);
1914 if (NewBitWidth < OldBitWidth)
1915 Int = Int.trunc(NewBitWidth).extend(OldBitWidth);
1919 static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
1922 if (!Evaluate(SVal, Info, E))
1925 Res = SVal.getInt();
1928 if (SVal.isFloat()) {
1929 Res = SVal.getFloat().bitcastToAPInt();
1932 if (SVal.isVector()) {
1933 QualType VecTy = E->getType();
1934 unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
1935 QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
1936 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
1937 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
1938 Res = llvm::APInt::getNullValue(VecSize);
1939 for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
1940 APValue &Elt = SVal.getVectorElt(i);
1941 llvm::APInt EltAsInt;
1943 EltAsInt = Elt.getInt();
1944 } else if (Elt.isFloat()) {
1945 EltAsInt = Elt.getFloat().bitcastToAPInt();
1947 // Don't try to handle vectors of anything other than int or float
1948 // (not sure if it's possible to hit this case).
1949 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1952 unsigned BaseEltSize = EltAsInt.getBitWidth();
1954 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
1956 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
1960 // Give up if the input isn't an int, float, or vector. For example, we
1961 // reject "(v4i16)(intptr_t)&a".
1962 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1966 /// Perform the given integer operation, which is known to need at most BitWidth
1967 /// bits, and check for overflow in the original type (if that type was not an
1969 template<typename Operation>
1970 static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
1971 const APSInt &LHS, const APSInt &RHS,
1972 unsigned BitWidth, Operation Op,
1974 if (LHS.isUnsigned()) {
1975 Result = Op(LHS, RHS);
1979 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
1980 Result = Value.trunc(LHS.getBitWidth());
1981 if (Result.extend(BitWidth) != Value) {
1982 if (Info.checkingForOverflow())
1983 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
1984 diag::warn_integer_constant_overflow)
1985 << Result.toString(10) << E->getType();
1987 return HandleOverflow(Info, E, Value, E->getType());
1992 /// Perform the given binary integer operation.
1993 static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS,
1994 BinaryOperatorKind Opcode, APSInt RHS,
2001 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
2002 std::multiplies<APSInt>(), Result);
2004 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2005 std::plus<APSInt>(), Result);
2007 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2008 std::minus<APSInt>(), Result);
2009 case BO_And: Result = LHS & RHS; return true;
2010 case BO_Xor: Result = LHS ^ RHS; return true;
2011 case BO_Or: Result = LHS | RHS; return true;
2015 Info.FFDiag(E, diag::note_expr_divide_by_zero);
2018 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
2019 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
2020 // this operation and gives the two's complement result.
2021 if (RHS.isNegative() && RHS.isAllOnesValue() &&
2022 LHS.isSigned() && LHS.isMinSignedValue())
2023 return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1),
2027 if (Info.getLangOpts().OpenCL)
2028 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2029 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2030 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2032 else if (RHS.isSigned() && RHS.isNegative()) {
2033 // During constant-folding, a negative shift is an opposite shift. Such
2034 // a shift is not a constant expression.
2035 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2040 // C++11 [expr.shift]p1: Shift width must be less than the bit width of
2041 // the shifted type.
2042 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2044 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2045 << RHS << E->getType() << LHS.getBitWidth();
2046 } else if (LHS.isSigned()) {
2047 // C++11 [expr.shift]p2: A signed left shift must have a non-negative
2048 // operand, and must not overflow the corresponding unsigned type.
2049 if (LHS.isNegative())
2050 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
2051 else if (LHS.countLeadingZeros() < SA)
2052 Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
2058 if (Info.getLangOpts().OpenCL)
2059 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2060 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2061 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2063 else if (RHS.isSigned() && RHS.isNegative()) {
2064 // During constant-folding, a negative shift is an opposite shift. Such a
2065 // shift is not a constant expression.
2066 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2071 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
2073 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2075 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2076 << RHS << E->getType() << LHS.getBitWidth();
2081 case BO_LT: Result = LHS < RHS; return true;
2082 case BO_GT: Result = LHS > RHS; return true;
2083 case BO_LE: Result = LHS <= RHS; return true;
2084 case BO_GE: Result = LHS >= RHS; return true;
2085 case BO_EQ: Result = LHS == RHS; return true;
2086 case BO_NE: Result = LHS != RHS; return true;
2090 /// Perform the given binary floating-point operation, in-place, on LHS.
2091 static bool handleFloatFloatBinOp(EvalInfo &Info, const Expr *E,
2092 APFloat &LHS, BinaryOperatorKind Opcode,
2093 const APFloat &RHS) {
2099 LHS.multiply(RHS, APFloat::rmNearestTiesToEven);
2102 LHS.add(RHS, APFloat::rmNearestTiesToEven);
2105 LHS.subtract(RHS, APFloat::rmNearestTiesToEven);
2108 LHS.divide(RHS, APFloat::rmNearestTiesToEven);
2112 if (LHS.isInfinity() || LHS.isNaN()) {
2113 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
2114 return Info.noteUndefinedBehavior();
2119 /// Cast an lvalue referring to a base subobject to a derived class, by
2120 /// truncating the lvalue's path to the given length.
2121 static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
2122 const RecordDecl *TruncatedType,
2123 unsigned TruncatedElements) {
2124 SubobjectDesignator &D = Result.Designator;
2126 // Check we actually point to a derived class object.
2127 if (TruncatedElements == D.Entries.size())
2129 assert(TruncatedElements >= D.MostDerivedPathLength &&
2130 "not casting to a derived class");
2131 if (!Result.checkSubobject(Info, E, CSK_Derived))
2134 // Truncate the path to the subobject, and remove any derived-to-base offsets.
2135 const RecordDecl *RD = TruncatedType;
2136 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
2137 if (RD->isInvalidDecl()) return false;
2138 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
2139 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
2140 if (isVirtualBaseClass(D.Entries[I]))
2141 Result.Offset -= Layout.getVBaseClassOffset(Base);
2143 Result.Offset -= Layout.getBaseClassOffset(Base);
2146 D.Entries.resize(TruncatedElements);
2150 static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2151 const CXXRecordDecl *Derived,
2152 const CXXRecordDecl *Base,
2153 const ASTRecordLayout *RL = nullptr) {
2155 if (Derived->isInvalidDecl()) return false;
2156 RL = &Info.Ctx.getASTRecordLayout(Derived);
2159 Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
2160 Obj.addDecl(Info, E, Base, /*Virtual*/ false);
2164 static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2165 const CXXRecordDecl *DerivedDecl,
2166 const CXXBaseSpecifier *Base) {
2167 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
2169 if (!Base->isVirtual())
2170 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
2172 SubobjectDesignator &D = Obj.Designator;
2176 // Extract most-derived object and corresponding type.
2177 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
2178 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
2181 // Find the virtual base class.
2182 if (DerivedDecl->isInvalidDecl()) return false;
2183 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
2184 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
2185 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
2189 static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
2190 QualType Type, LValue &Result) {
2191 for (CastExpr::path_const_iterator PathI = E->path_begin(),
2192 PathE = E->path_end();
2193 PathI != PathE; ++PathI) {
2194 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
2197 Type = (*PathI)->getType();
2202 /// Update LVal to refer to the given field, which must be a member of the type
2203 /// currently described by LVal.
2204 static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
2205 const FieldDecl *FD,
2206 const ASTRecordLayout *RL = nullptr) {
2208 if (FD->getParent()->isInvalidDecl()) return false;
2209 RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
2212 unsigned I = FD->getFieldIndex();
2213 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)));
2214 LVal.addDecl(Info, E, FD);
2218 /// Update LVal to refer to the given indirect field.
2219 static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
2221 const IndirectFieldDecl *IFD) {
2222 for (const auto *C : IFD->chain())
2223 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C)))
2228 /// Get the size of the given type in char units.
2229 static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
2230 QualType Type, CharUnits &Size) {
2231 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
2233 if (Type->isVoidType() || Type->isFunctionType()) {
2234 Size = CharUnits::One();
2238 if (Type->isDependentType()) {
2243 if (!Type->isConstantSizeType()) {
2244 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
2245 // FIXME: Better diagnostic.
2250 Size = Info.Ctx.getTypeSizeInChars(Type);
2254 /// Update a pointer value to model pointer arithmetic.
2255 /// \param Info - Information about the ongoing evaluation.
2256 /// \param E - The expression being evaluated, for diagnostic purposes.
2257 /// \param LVal - The pointer value to be updated.
2258 /// \param EltTy - The pointee type represented by LVal.
2259 /// \param Adjustment - The adjustment, in objects of type EltTy, to add.
2260 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
2261 LValue &LVal, QualType EltTy,
2262 APSInt Adjustment) {
2263 CharUnits SizeOfPointee;
2264 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
2267 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee);
2271 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
2272 LValue &LVal, QualType EltTy,
2273 int64_t Adjustment) {
2274 return HandleLValueArrayAdjustment(Info, E, LVal, EltTy,
2275 APSInt::get(Adjustment));
2278 /// Update an lvalue to refer to a component of a complex number.
2279 /// \param Info - Information about the ongoing evaluation.
2280 /// \param LVal - The lvalue to be updated.
2281 /// \param EltTy - The complex number's component type.
2282 /// \param Imag - False for the real component, true for the imaginary.
2283 static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
2284 LValue &LVal, QualType EltTy,
2287 CharUnits SizeOfComponent;
2288 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
2290 LVal.Offset += SizeOfComponent;
2292 LVal.addComplex(Info, E, EltTy, Imag);
2296 static bool handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv,
2297 QualType Type, const LValue &LVal,
2300 /// Try to evaluate the initializer for a variable declaration.
2302 /// \param Info Information about the ongoing evaluation.
2303 /// \param E An expression to be used when printing diagnostics.
2304 /// \param VD The variable whose initializer should be obtained.
2305 /// \param Frame The frame in which the variable was created. Must be null
2306 /// if this variable is not local to the evaluation.
2307 /// \param Result Filled in with a pointer to the value of the variable.
2308 static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
2309 const VarDecl *VD, CallStackFrame *Frame,
2312 // If this is a parameter to an active constexpr function call, perform
2313 // argument substitution.
2314 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) {
2315 // Assume arguments of a potential constant expression are unknown
2316 // constant expressions.
2317 if (Info.checkingPotentialConstantExpression())
2319 if (!Frame || !Frame->Arguments) {
2320 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2323 Result = &Frame->Arguments[PVD->getFunctionScopeIndex()];
2327 // If this is a local variable, dig out its value.
2329 Result = Frame->getTemporary(VD);
2331 // Assume variables referenced within a lambda's call operator that were
2332 // not declared within the call operator are captures and during checking
2333 // of a potential constant expression, assume they are unknown constant
2335 assert(isLambdaCallOperator(Frame->Callee) &&
2336 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&
2337 "missing value for local variable");
2338 if (Info.checkingPotentialConstantExpression())
2340 // FIXME: implement capture evaluation during constant expr evaluation.
2341 Info.FFDiag(E->getLocStart(),
2342 diag::note_unimplemented_constexpr_lambda_feature_ast)
2343 << "captures not currently allowed";
2349 // Dig out the initializer, and use the declaration which it's attached to.
2350 const Expr *Init = VD->getAnyInitializer(VD);
2351 if (!Init || Init->isValueDependent()) {
2352 // If we're checking a potential constant expression, the variable could be
2353 // initialized later.
2354 if (!Info.checkingPotentialConstantExpression())
2355 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2359 // If we're currently evaluating the initializer of this declaration, use that
2361 if (Info.EvaluatingDecl.dyn_cast<const ValueDecl*>() == VD) {
2362 Result = Info.EvaluatingDeclValue;
2366 // Never evaluate the initializer of a weak variable. We can't be sure that
2367 // this is the definition which will be used.
2369 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2373 // Check that we can fold the initializer. In C++, we will have already done
2374 // this in the cases where it matters for conformance.
2375 SmallVector<PartialDiagnosticAt, 8> Notes;
2376 if (!VD->evaluateValue(Notes)) {
2377 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant,
2378 Notes.size() + 1) << VD;
2379 Info.Note(VD->getLocation(), diag::note_declared_at);
2380 Info.addNotes(Notes);
2382 } else if (!VD->checkInitIsICE()) {
2383 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant,
2384 Notes.size() + 1) << VD;
2385 Info.Note(VD->getLocation(), diag::note_declared_at);
2386 Info.addNotes(Notes);
2389 Result = VD->getEvaluatedValue();
2393 static bool IsConstNonVolatile(QualType T) {
2394 Qualifiers Quals = T.getQualifiers();
2395 return Quals.hasConst() && !Quals.hasVolatile();
2398 /// Get the base index of the given base class within an APValue representing
2399 /// the given derived class.
2400 static unsigned getBaseIndex(const CXXRecordDecl *Derived,
2401 const CXXRecordDecl *Base) {
2402 Base = Base->getCanonicalDecl();
2404 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
2405 E = Derived->bases_end(); I != E; ++I, ++Index) {
2406 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
2410 llvm_unreachable("base class missing from derived class's bases list");
2413 /// Extract the value of a character from a string literal.
2414 static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
2416 // FIXME: Support MakeStringConstant
2417 if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) {
2419 Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str);
2420 assert(Index <= Str.size() && "Index too large");
2421 return APSInt::getUnsigned(Str.c_str()[Index]);
2424 if (auto PE = dyn_cast<PredefinedExpr>(Lit))
2425 Lit = PE->getFunctionName();
2426 const StringLiteral *S = cast<StringLiteral>(Lit);
2427 const ConstantArrayType *CAT =
2428 Info.Ctx.getAsConstantArrayType(S->getType());
2429 assert(CAT && "string literal isn't an array");
2430 QualType CharType = CAT->getElementType();
2431 assert(CharType->isIntegerType() && "unexpected character type");
2433 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
2434 CharType->isUnsignedIntegerType());
2435 if (Index < S->getLength())
2436 Value = S->getCodeUnit(Index);
2440 // Expand a string literal into an array of characters.
2441 static void expandStringLiteral(EvalInfo &Info, const Expr *Lit,
2443 const StringLiteral *S = cast<StringLiteral>(Lit);
2444 const ConstantArrayType *CAT =
2445 Info.Ctx.getAsConstantArrayType(S->getType());
2446 assert(CAT && "string literal isn't an array");
2447 QualType CharType = CAT->getElementType();
2448 assert(CharType->isIntegerType() && "unexpected character type");
2450 unsigned Elts = CAT->getSize().getZExtValue();
2451 Result = APValue(APValue::UninitArray(),
2452 std::min(S->getLength(), Elts), Elts);
2453 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
2454 CharType->isUnsignedIntegerType());
2455 if (Result.hasArrayFiller())
2456 Result.getArrayFiller() = APValue(Value);
2457 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
2458 Value = S->getCodeUnit(I);
2459 Result.getArrayInitializedElt(I) = APValue(Value);
2463 // Expand an array so that it has more than Index filled elements.
2464 static void expandArray(APValue &Array, unsigned Index) {
2465 unsigned Size = Array.getArraySize();
2466 assert(Index < Size);
2468 // Always at least double the number of elements for which we store a value.
2469 unsigned OldElts = Array.getArrayInitializedElts();
2470 unsigned NewElts = std::max(Index+1, OldElts * 2);
2471 NewElts = std::min(Size, std::max(NewElts, 8u));
2473 // Copy the data across.
2474 APValue NewValue(APValue::UninitArray(), NewElts, Size);
2475 for (unsigned I = 0; I != OldElts; ++I)
2476 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I));
2477 for (unsigned I = OldElts; I != NewElts; ++I)
2478 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
2479 if (NewValue.hasArrayFiller())
2480 NewValue.getArrayFiller() = Array.getArrayFiller();
2481 Array.swap(NewValue);
2484 /// Determine whether a type would actually be read by an lvalue-to-rvalue
2485 /// conversion. If it's of class type, we may assume that the copy operation
2486 /// is trivial. Note that this is never true for a union type with fields
2487 /// (because the copy always "reads" the active member) and always true for
2488 /// a non-class type.
2489 static bool isReadByLvalueToRvalueConversion(QualType T) {
2490 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
2491 if (!RD || (RD->isUnion() && !RD->field_empty()))
2496 for (auto *Field : RD->fields())
2497 if (isReadByLvalueToRvalueConversion(Field->getType()))
2500 for (auto &BaseSpec : RD->bases())
2501 if (isReadByLvalueToRvalueConversion(BaseSpec.getType()))
2507 /// Diagnose an attempt to read from any unreadable field within the specified
2508 /// type, which might be a class type.
2509 static bool diagnoseUnreadableFields(EvalInfo &Info, const Expr *E,
2511 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
2515 if (!RD->hasMutableFields())
2518 for (auto *Field : RD->fields()) {
2519 // If we're actually going to read this field in some way, then it can't
2520 // be mutable. If we're in a union, then assigning to a mutable field
2521 // (even an empty one) can change the active member, so that's not OK.
2522 // FIXME: Add core issue number for the union case.
2523 if (Field->isMutable() &&
2524 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
2525 Info.FFDiag(E, diag::note_constexpr_ltor_mutable, 1) << Field;
2526 Info.Note(Field->getLocation(), diag::note_declared_at);
2530 if (diagnoseUnreadableFields(Info, E, Field->getType()))
2534 for (auto &BaseSpec : RD->bases())
2535 if (diagnoseUnreadableFields(Info, E, BaseSpec.getType()))
2538 // All mutable fields were empty, and thus not actually read.
2542 /// Kinds of access we can perform on an object, for diagnostics.
2551 /// A handle to a complete object (an object that is not a subobject of
2552 /// another object).
2553 struct CompleteObject {
2554 /// The value of the complete object.
2556 /// The type of the complete object.
2559 CompleteObject() : Value(nullptr) {}
2560 CompleteObject(APValue *Value, QualType Type)
2561 : Value(Value), Type(Type) {
2562 assert(Value && "missing value for complete object");
2565 explicit operator bool() const { return Value; }
2567 } // end anonymous namespace
2569 /// Find the designated sub-object of an rvalue.
2570 template<typename SubobjectHandler>
2571 typename SubobjectHandler::result_type
2572 findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
2573 const SubobjectDesignator &Sub, SubobjectHandler &handler) {
2575 // A diagnostic will have already been produced.
2576 return handler.failed();
2577 if (Sub.isOnePastTheEnd()) {
2578 if (Info.getLangOpts().CPlusPlus11)
2579 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2580 << handler.AccessKind;
2583 return handler.failed();
2586 APValue *O = Obj.Value;
2587 QualType ObjType = Obj.Type;
2588 const FieldDecl *LastField = nullptr;
2590 // Walk the designator's path to find the subobject.
2591 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
2592 if (O->isUninit()) {
2593 if (!Info.checkingPotentialConstantExpression())
2594 Info.FFDiag(E, diag::note_constexpr_access_uninit) << handler.AccessKind;
2595 return handler.failed();
2599 // If we are reading an object of class type, there may still be more
2600 // things we need to check: if there are any mutable subobjects, we
2601 // cannot perform this read. (This only happens when performing a trivial
2602 // copy or assignment.)
2603 if (ObjType->isRecordType() && handler.AccessKind == AK_Read &&
2604 diagnoseUnreadableFields(Info, E, ObjType))
2605 return handler.failed();
2607 if (!handler.found(*O, ObjType))
2610 // If we modified a bit-field, truncate it to the right width.
2611 if (handler.AccessKind != AK_Read &&
2612 LastField && LastField->isBitField() &&
2613 !truncateBitfieldValue(Info, E, *O, LastField))
2619 LastField = nullptr;
2620 if (ObjType->isArrayType()) {
2621 // Next subobject is an array element.
2622 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
2623 assert(CAT && "vla in literal type?");
2624 uint64_t Index = Sub.Entries[I].ArrayIndex;
2625 if (CAT->getSize().ule(Index)) {
2626 // Note, it should not be possible to form a pointer with a valid
2627 // designator which points more than one past the end of the array.
2628 if (Info.getLangOpts().CPlusPlus11)
2629 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2630 << handler.AccessKind;
2633 return handler.failed();
2636 ObjType = CAT->getElementType();
2638 // An array object is represented as either an Array APValue or as an
2639 // LValue which refers to a string literal.
2640 if (O->isLValue()) {
2641 assert(I == N - 1 && "extracting subobject of character?");
2642 assert(!O->hasLValuePath() || O->getLValuePath().empty());
2643 if (handler.AccessKind != AK_Read)
2644 expandStringLiteral(Info, O->getLValueBase().get<const Expr *>(),
2647 return handler.foundString(*O, ObjType, Index);
2650 if (O->getArrayInitializedElts() > Index)
2651 O = &O->getArrayInitializedElt(Index);
2652 else if (handler.AccessKind != AK_Read) {
2653 expandArray(*O, Index);
2654 O = &O->getArrayInitializedElt(Index);
2656 O = &O->getArrayFiller();
2657 } else if (ObjType->isAnyComplexType()) {
2658 // Next subobject is a complex number.
2659 uint64_t Index = Sub.Entries[I].ArrayIndex;
2661 if (Info.getLangOpts().CPlusPlus11)
2662 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2663 << handler.AccessKind;
2666 return handler.failed();
2669 bool WasConstQualified = ObjType.isConstQualified();
2670 ObjType = ObjType->castAs<ComplexType>()->getElementType();
2671 if (WasConstQualified)
2674 assert(I == N - 1 && "extracting subobject of scalar?");
2675 if (O->isComplexInt()) {
2676 return handler.found(Index ? O->getComplexIntImag()
2677 : O->getComplexIntReal(), ObjType);
2679 assert(O->isComplexFloat());
2680 return handler.found(Index ? O->getComplexFloatImag()
2681 : O->getComplexFloatReal(), ObjType);
2683 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
2684 if (Field->isMutable() && handler.AccessKind == AK_Read) {
2685 Info.FFDiag(E, diag::note_constexpr_ltor_mutable, 1)
2687 Info.Note(Field->getLocation(), diag::note_declared_at);
2688 return handler.failed();
2691 // Next subobject is a class, struct or union field.
2692 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
2693 if (RD->isUnion()) {
2694 const FieldDecl *UnionField = O->getUnionField();
2696 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
2697 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
2698 << handler.AccessKind << Field << !UnionField << UnionField;
2699 return handler.failed();
2701 O = &O->getUnionValue();
2703 O = &O->getStructField(Field->getFieldIndex());
2705 bool WasConstQualified = ObjType.isConstQualified();
2706 ObjType = Field->getType();
2707 if (WasConstQualified && !Field->isMutable())
2710 if (ObjType.isVolatileQualified()) {
2711 if (Info.getLangOpts().CPlusPlus) {
2712 // FIXME: Include a description of the path to the volatile subobject.
2713 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
2714 << handler.AccessKind << 2 << Field;
2715 Info.Note(Field->getLocation(), diag::note_declared_at);
2717 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2719 return handler.failed();
2724 // Next subobject is a base class.
2725 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
2726 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
2727 O = &O->getStructBase(getBaseIndex(Derived, Base));
2729 bool WasConstQualified = ObjType.isConstQualified();
2730 ObjType = Info.Ctx.getRecordType(Base);
2731 if (WasConstQualified)
2738 struct ExtractSubobjectHandler {
2742 static const AccessKinds AccessKind = AK_Read;
2744 typedef bool result_type;
2745 bool failed() { return false; }
2746 bool found(APValue &Subobj, QualType SubobjType) {
2750 bool found(APSInt &Value, QualType SubobjType) {
2751 Result = APValue(Value);
2754 bool found(APFloat &Value, QualType SubobjType) {
2755 Result = APValue(Value);
2758 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
2759 Result = APValue(extractStringLiteralCharacter(
2760 Info, Subobj.getLValueBase().get<const Expr *>(), Character));
2764 } // end anonymous namespace
2766 const AccessKinds ExtractSubobjectHandler::AccessKind;
2768 /// Extract the designated sub-object of an rvalue.
2769 static bool extractSubobject(EvalInfo &Info, const Expr *E,
2770 const CompleteObject &Obj,
2771 const SubobjectDesignator &Sub,
2773 ExtractSubobjectHandler Handler = { Info, Result };
2774 return findSubobject(Info, E, Obj, Sub, Handler);
2778 struct ModifySubobjectHandler {
2783 typedef bool result_type;
2784 static const AccessKinds AccessKind = AK_Assign;
2786 bool checkConst(QualType QT) {
2787 // Assigning to a const object has undefined behavior.
2788 if (QT.isConstQualified()) {
2789 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
2795 bool failed() { return false; }
2796 bool found(APValue &Subobj, QualType SubobjType) {
2797 if (!checkConst(SubobjType))
2799 // We've been given ownership of NewVal, so just swap it in.
2800 Subobj.swap(NewVal);
2803 bool found(APSInt &Value, QualType SubobjType) {
2804 if (!checkConst(SubobjType))
2806 if (!NewVal.isInt()) {
2807 // Maybe trying to write a cast pointer value into a complex?
2811 Value = NewVal.getInt();
2814 bool found(APFloat &Value, QualType SubobjType) {
2815 if (!checkConst(SubobjType))
2817 Value = NewVal.getFloat();
2820 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
2821 llvm_unreachable("shouldn't encounter string elements with ExpandArrays");
2824 } // end anonymous namespace
2826 const AccessKinds ModifySubobjectHandler::AccessKind;
2828 /// Update the designated sub-object of an rvalue to the given value.
2829 static bool modifySubobject(EvalInfo &Info, const Expr *E,
2830 const CompleteObject &Obj,
2831 const SubobjectDesignator &Sub,
2833 ModifySubobjectHandler Handler = { Info, NewVal, E };
2834 return findSubobject(Info, E, Obj, Sub, Handler);
2837 /// Find the position where two subobject designators diverge, or equivalently
2838 /// the length of the common initial subsequence.
2839 static unsigned FindDesignatorMismatch(QualType ObjType,
2840 const SubobjectDesignator &A,
2841 const SubobjectDesignator &B,
2842 bool &WasArrayIndex) {
2843 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
2844 for (/**/; I != N; ++I) {
2845 if (!ObjType.isNull() &&
2846 (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
2847 // Next subobject is an array element.
2848 if (A.Entries[I].ArrayIndex != B.Entries[I].ArrayIndex) {
2849 WasArrayIndex = true;
2852 if (ObjType->isAnyComplexType())
2853 ObjType = ObjType->castAs<ComplexType>()->getElementType();
2855 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
2857 if (A.Entries[I].BaseOrMember != B.Entries[I].BaseOrMember) {
2858 WasArrayIndex = false;
2861 if (const FieldDecl *FD = getAsField(A.Entries[I]))
2862 // Next subobject is a field.
2863 ObjType = FD->getType();
2865 // Next subobject is a base class.
2866 ObjType = QualType();
2869 WasArrayIndex = false;
2873 /// Determine whether the given subobject designators refer to elements of the
2874 /// same array object.
2875 static bool AreElementsOfSameArray(QualType ObjType,
2876 const SubobjectDesignator &A,
2877 const SubobjectDesignator &B) {
2878 if (A.Entries.size() != B.Entries.size())
2881 bool IsArray = A.MostDerivedIsArrayElement;
2882 if (IsArray && A.MostDerivedPathLength != A.Entries.size())
2883 // A is a subobject of the array element.
2886 // If A (and B) designates an array element, the last entry will be the array
2887 // index. That doesn't have to match. Otherwise, we're in the 'implicit array
2888 // of length 1' case, and the entire path must match.
2890 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
2891 return CommonLength >= A.Entries.size() - IsArray;
2894 /// Find the complete object to which an LValue refers.
2895 static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
2896 AccessKinds AK, const LValue &LVal,
2897 QualType LValType) {
2899 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
2900 return CompleteObject();
2903 CallStackFrame *Frame = nullptr;
2904 if (LVal.CallIndex) {
2905 Frame = Info.getCallFrame(LVal.CallIndex);
2907 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
2908 << AK << LVal.Base.is<const ValueDecl*>();
2909 NoteLValueLocation(Info, LVal.Base);
2910 return CompleteObject();
2914 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
2915 // is not a constant expression (even if the object is non-volatile). We also
2916 // apply this rule to C++98, in order to conform to the expected 'volatile'
2918 if (LValType.isVolatileQualified()) {
2919 if (Info.getLangOpts().CPlusPlus)
2920 Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
2924 return CompleteObject();
2927 // Compute value storage location and type of base object.
2928 APValue *BaseVal = nullptr;
2929 QualType BaseType = getType(LVal.Base);
2931 if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl*>()) {
2932 // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
2933 // In C++11, constexpr, non-volatile variables initialized with constant
2934 // expressions are constant expressions too. Inside constexpr functions,
2935 // parameters are constant expressions even if they're non-const.
2936 // In C++1y, objects local to a constant expression (those with a Frame) are
2937 // both readable and writable inside constant expressions.
2938 // In C, such things can also be folded, although they are not ICEs.
2939 const VarDecl *VD = dyn_cast<VarDecl>(D);
2941 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
2944 if (!VD || VD->isInvalidDecl()) {
2946 return CompleteObject();
2949 // Accesses of volatile-qualified objects are not allowed.
2950 if (BaseType.isVolatileQualified()) {
2951 if (Info.getLangOpts().CPlusPlus) {
2952 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
2954 Info.Note(VD->getLocation(), diag::note_declared_at);
2958 return CompleteObject();
2961 // Unless we're looking at a local variable or argument in a constexpr call,
2962 // the variable we're reading must be const.
2964 if (Info.getLangOpts().CPlusPlus14 &&
2965 VD == Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()) {
2966 // OK, we can read and modify an object if we're in the process of
2967 // evaluating its initializer, because its lifetime began in this
2969 } else if (AK != AK_Read) {
2970 // All the remaining cases only permit reading.
2971 Info.FFDiag(E, diag::note_constexpr_modify_global);
2972 return CompleteObject();
2973 } else if (VD->isConstexpr()) {
2974 // OK, we can read this variable.
2975 } else if (BaseType->isIntegralOrEnumerationType()) {
2976 // In OpenCL if a variable is in constant address space it is a const value.
2977 if (!(BaseType.isConstQualified() ||
2978 (Info.getLangOpts().OpenCL &&
2979 BaseType.getAddressSpace() == LangAS::opencl_constant))) {
2980 if (Info.getLangOpts().CPlusPlus) {
2981 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
2982 Info.Note(VD->getLocation(), diag::note_declared_at);
2986 return CompleteObject();
2988 } else if (BaseType->isFloatingType() && BaseType.isConstQualified()) {
2989 // We support folding of const floating-point types, in order to make
2990 // static const data members of such types (supported as an extension)
2992 if (Info.getLangOpts().CPlusPlus11) {
2993 Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
2994 Info.Note(VD->getLocation(), diag::note_declared_at);
2998 } else if (BaseType.isConstQualified() && VD->hasDefinition(Info.Ctx)) {
2999 Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr) << VD;
3000 // Keep evaluating to see what we can do.
3002 // FIXME: Allow folding of values of any literal type in all languages.
3003 if (Info.checkingPotentialConstantExpression() &&
3004 VD->getType().isConstQualified() && !VD->hasDefinition(Info.Ctx)) {
3005 // The definition of this variable could be constexpr. We can't
3006 // access it right now, but may be able to in future.
3007 } else if (Info.getLangOpts().CPlusPlus11) {
3008 Info.FFDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
3009 Info.Note(VD->getLocation(), diag::note_declared_at);
3013 return CompleteObject();
3017 if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal))
3018 return CompleteObject();
3020 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
3023 if (const MaterializeTemporaryExpr *MTE =
3024 dyn_cast<MaterializeTemporaryExpr>(Base)) {
3025 assert(MTE->getStorageDuration() == SD_Static &&
3026 "should have a frame for a non-global materialized temporary");
3028 // Per C++1y [expr.const]p2:
3029 // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
3030 // - a [...] glvalue of integral or enumeration type that refers to
3031 // a non-volatile const object [...]
3033 // - a [...] glvalue of literal type that refers to a non-volatile
3034 // object whose lifetime began within the evaluation of e.
3036 // C++11 misses the 'began within the evaluation of e' check and
3037 // instead allows all temporaries, including things like:
3040 // constexpr int k = r;
3041 // Therefore we use the C++1y rules in C++11 too.
3042 const ValueDecl *VD = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>();
3043 const ValueDecl *ED = MTE->getExtendingDecl();
3044 if (!(BaseType.isConstQualified() &&
3045 BaseType->isIntegralOrEnumerationType()) &&
3046 !(VD && VD->getCanonicalDecl() == ED->getCanonicalDecl())) {
3047 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
3048 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
3049 return CompleteObject();
3052 BaseVal = Info.Ctx.getMaterializedTemporaryValue(MTE, false);
3053 assert(BaseVal && "got reference to unevaluated temporary");
3056 return CompleteObject();
3059 BaseVal = Frame->getTemporary(Base);
3060 assert(BaseVal && "missing value for temporary");
3063 // Volatile temporary objects cannot be accessed in constant expressions.
3064 if (BaseType.isVolatileQualified()) {
3065 if (Info.getLangOpts().CPlusPlus) {
3066 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
3068 Info.Note(Base->getExprLoc(), diag::note_constexpr_temporary_here);
3072 return CompleteObject();
3076 // During the construction of an object, it is not yet 'const'.
3077 // FIXME: We don't set up EvaluatingDecl for local variables or temporaries,
3078 // and this doesn't do quite the right thing for const subobjects of the
3079 // object under construction.
3080 if (LVal.getLValueBase() == Info.EvaluatingDecl) {
3081 BaseType = Info.Ctx.getCanonicalType(BaseType);
3082 BaseType.removeLocalConst();
3085 // In C++1y, we can't safely access any mutable state when we might be
3086 // evaluating after an unmodeled side effect.
3088 // FIXME: Not all local state is mutable. Allow local constant subobjects
3089 // to be read here (but take care with 'mutable' fields).
3090 if ((Frame && Info.getLangOpts().CPlusPlus14 &&
3091 Info.EvalStatus.HasSideEffects) ||
3092 (AK != AK_Read && Info.IsSpeculativelyEvaluating))
3093 return CompleteObject();
3095 return CompleteObject(BaseVal, BaseType);
3098 /// \brief Perform an lvalue-to-rvalue conversion on the given glvalue. This
3099 /// can also be used for 'lvalue-to-lvalue' conversions for looking up the
3100 /// glvalue referred to by an entity of reference type.
3102 /// \param Info - Information about the ongoing evaluation.
3103 /// \param Conv - The expression for which we are performing the conversion.
3104 /// Used for diagnostics.
3105 /// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
3106 /// case of a non-class type).
3107 /// \param LVal - The glvalue on which we are attempting to perform this action.
3108 /// \param RVal - The produced value will be placed here.
3109 static bool handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv,
3111 const LValue &LVal, APValue &RVal) {
3112 if (LVal.Designator.Invalid)
3115 // Check for special cases where there is no existing APValue to look at.
3116 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
3117 if (Base && !LVal.CallIndex && !Type.isVolatileQualified()) {
3118 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) {
3119 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
3120 // initializer until now for such expressions. Such an expression can't be
3121 // an ICE in C, so this only matters for fold.
3122 if (Type.isVolatileQualified()) {
3127 if (!Evaluate(Lit, Info, CLE->getInitializer()))
3129 CompleteObject LitObj(&Lit, Base->getType());
3130 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal);
3131 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) {
3132 // We represent a string literal array as an lvalue pointing at the
3133 // corresponding expression, rather than building an array of chars.
3134 // FIXME: Support ObjCEncodeExpr, MakeStringConstant
3135 APValue Str(Base, CharUnits::Zero(), APValue::NoLValuePath(), 0);
3136 CompleteObject StrObj(&Str, Base->getType());
3137 return extractSubobject(Info, Conv, StrObj, LVal.Designator, RVal);
3141 CompleteObject Obj = findCompleteObject(Info, Conv, AK_Read, LVal, Type);
3142 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal);
3145 /// Perform an assignment of Val to LVal. Takes ownership of Val.
3146 static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
3147 QualType LValType, APValue &Val) {
3148 if (LVal.Designator.Invalid)
3151 if (!Info.getLangOpts().CPlusPlus14) {
3156 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
3157 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
3160 static bool isOverflowingIntegerType(ASTContext &Ctx, QualType T) {
3161 return T->isSignedIntegerType() &&
3162 Ctx.getIntWidth(T) >= Ctx.getIntWidth(Ctx.IntTy);
3166 struct CompoundAssignSubobjectHandler {
3169 QualType PromotedLHSType;
3170 BinaryOperatorKind Opcode;
3173 static const AccessKinds AccessKind = AK_Assign;
3175 typedef bool result_type;
3177 bool checkConst(QualType QT) {
3178 // Assigning to a const object has undefined behavior.
3179 if (QT.isConstQualified()) {
3180 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3186 bool failed() { return false; }
3187 bool found(APValue &Subobj, QualType SubobjType) {
3188 switch (Subobj.getKind()) {
3190 return found(Subobj.getInt(), SubobjType);
3191 case APValue::Float:
3192 return found(Subobj.getFloat(), SubobjType);
3193 case APValue::ComplexInt:
3194 case APValue::ComplexFloat:
3195 // FIXME: Implement complex compound assignment.
3198 case APValue::LValue:
3199 return foundPointer(Subobj, SubobjType);
3201 // FIXME: can this happen?
3206 bool found(APSInt &Value, QualType SubobjType) {
3207 if (!checkConst(SubobjType))
3210 if (!SubobjType->isIntegerType() || !RHS.isInt()) {
3211 // We don't support compound assignment on integer-cast-to-pointer
3217 APSInt LHS = HandleIntToIntCast(Info, E, PromotedLHSType,
3219 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
3221 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
3224 bool found(APFloat &Value, QualType SubobjType) {
3225 return checkConst(SubobjType) &&
3226 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
3228 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
3229 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
3231 bool foundPointer(APValue &Subobj, QualType SubobjType) {
3232 if (!checkConst(SubobjType))
3235 QualType PointeeType;
3236 if (const PointerType *PT = SubobjType->getAs<PointerType>())
3237 PointeeType = PT->getPointeeType();
3239 if (PointeeType.isNull() || !RHS.isInt() ||
3240 (Opcode != BO_Add && Opcode != BO_Sub)) {
3245 APSInt Offset = RHS.getInt();
3246 if (Opcode == BO_Sub)
3247 negateAsSigned(Offset);
3250 LVal.setFrom(Info.Ctx, Subobj);
3251 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
3253 LVal.moveInto(Subobj);
3256 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
3257 llvm_unreachable("shouldn't encounter string elements here");
3260 } // end anonymous namespace
3262 const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
3264 /// Perform a compound assignment of LVal <op>= RVal.
3265 static bool handleCompoundAssignment(
3266 EvalInfo &Info, const Expr *E,
3267 const LValue &LVal, QualType LValType, QualType PromotedLValType,
3268 BinaryOperatorKind Opcode, const APValue &RVal) {
3269 if (LVal.Designator.Invalid)
3272 if (!Info.getLangOpts().CPlusPlus14) {
3277 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
3278 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
3280 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
3284 struct IncDecSubobjectHandler {
3287 AccessKinds AccessKind;
3290 typedef bool result_type;
3292 bool checkConst(QualType QT) {
3293 // Assigning to a const object has undefined behavior.
3294 if (QT.isConstQualified()) {
3295 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3301 bool failed() { return false; }
3302 bool found(APValue &Subobj, QualType SubobjType) {
3303 // Stash the old value. Also clear Old, so we don't clobber it later
3304 // if we're post-incrementing a complex.
3310 switch (Subobj.getKind()) {
3312 return found(Subobj.getInt(), SubobjType);
3313 case APValue::Float:
3314 return found(Subobj.getFloat(), SubobjType);
3315 case APValue::ComplexInt:
3316 return found(Subobj.getComplexIntReal(),
3317 SubobjType->castAs<ComplexType>()->getElementType()
3318 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
3319 case APValue::ComplexFloat:
3320 return found(Subobj.getComplexFloatReal(),
3321 SubobjType->castAs<ComplexType>()->getElementType()
3322 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
3323 case APValue::LValue:
3324 return foundPointer(Subobj, SubobjType);
3326 // FIXME: can this happen?
3331 bool found(APSInt &Value, QualType SubobjType) {
3332 if (!checkConst(SubobjType))
3335 if (!SubobjType->isIntegerType()) {
3336 // We don't support increment / decrement on integer-cast-to-pointer
3342 if (Old) *Old = APValue(Value);
3344 // bool arithmetic promotes to int, and the conversion back to bool
3345 // doesn't reduce mod 2^n, so special-case it.
3346 if (SubobjType->isBooleanType()) {
3347 if (AccessKind == AK_Increment)
3354 bool WasNegative = Value.isNegative();
3355 if (AccessKind == AK_Increment) {
3358 if (!WasNegative && Value.isNegative() &&
3359 isOverflowingIntegerType(Info.Ctx, SubobjType)) {
3360 APSInt ActualValue(Value, /*IsUnsigned*/true);
3361 return HandleOverflow(Info, E, ActualValue, SubobjType);
3366 if (WasNegative && !Value.isNegative() &&
3367 isOverflowingIntegerType(Info.Ctx, SubobjType)) {
3368 unsigned BitWidth = Value.getBitWidth();
3369 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
3370 ActualValue.setBit(BitWidth);
3371 return HandleOverflow(Info, E, ActualValue, SubobjType);
3376 bool found(APFloat &Value, QualType SubobjType) {
3377 if (!checkConst(SubobjType))
3380 if (Old) *Old = APValue(Value);
3382 APFloat One(Value.getSemantics(), 1);
3383 if (AccessKind == AK_Increment)
3384 Value.add(One, APFloat::rmNearestTiesToEven);
3386 Value.subtract(One, APFloat::rmNearestTiesToEven);
3389 bool foundPointer(APValue &Subobj, QualType SubobjType) {
3390 if (!checkConst(SubobjType))
3393 QualType PointeeType;
3394 if (const PointerType *PT = SubobjType->getAs<PointerType>())
3395 PointeeType = PT->getPointeeType();
3402 LVal.setFrom(Info.Ctx, Subobj);
3403 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
3404 AccessKind == AK_Increment ? 1 : -1))
3406 LVal.moveInto(Subobj);
3409 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
3410 llvm_unreachable("shouldn't encounter string elements here");
3413 } // end anonymous namespace
3415 /// Perform an increment or decrement on LVal.
3416 static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
3417 QualType LValType, bool IsIncrement, APValue *Old) {
3418 if (LVal.Designator.Invalid)
3421 if (!Info.getLangOpts().CPlusPlus14) {
3426 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
3427 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
3428 IncDecSubobjectHandler Handler = { Info, E, AK, Old };
3429 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
3432 /// Build an lvalue for the object argument of a member function call.
3433 static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
3435 if (Object->getType()->isPointerType())
3436 return EvaluatePointer(Object, This, Info);
3438 if (Object->isGLValue())
3439 return EvaluateLValue(Object, This, Info);
3441 if (Object->getType()->isLiteralType(Info.Ctx))
3442 return EvaluateTemporary(Object, This, Info);
3444 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
3448 /// HandleMemberPointerAccess - Evaluate a member access operation and build an
3449 /// lvalue referring to the result.
3451 /// \param Info - Information about the ongoing evaluation.
3452 /// \param LV - An lvalue referring to the base of the member pointer.
3453 /// \param RHS - The member pointer expression.
3454 /// \param IncludeMember - Specifies whether the member itself is included in
3455 /// the resulting LValue subobject designator. This is not possible when
3456 /// creating a bound member function.
3457 /// \return The field or method declaration to which the member pointer refers,
3458 /// or 0 if evaluation fails.
3459 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
3463 bool IncludeMember = true) {
3465 if (!EvaluateMemberPointer(RHS, MemPtr, Info))
3468 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
3469 // member value, the behavior is undefined.
3470 if (!MemPtr.getDecl()) {
3471 // FIXME: Specific diagnostic.
3476 if (MemPtr.isDerivedMember()) {
3477 // This is a member of some derived class. Truncate LV appropriately.
3478 // The end of the derived-to-base path for the base object must match the
3479 // derived-to-base path for the member pointer.
3480 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
3481 LV.Designator.Entries.size()) {
3485 unsigned PathLengthToMember =
3486 LV.Designator.Entries.size() - MemPtr.Path.size();
3487 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
3488 const CXXRecordDecl *LVDecl = getAsBaseClass(
3489 LV.Designator.Entries[PathLengthToMember + I]);
3490 const CXXRecordDecl *MPDecl = MemPtr.Path[I];
3491 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
3497 // Truncate the lvalue to the appropriate derived class.
3498 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
3499 PathLengthToMember))
3501 } else if (!MemPtr.Path.empty()) {
3502 // Extend the LValue path with the member pointer's path.
3503 LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
3504 MemPtr.Path.size() + IncludeMember);
3506 // Walk down to the appropriate base class.
3507 if (const PointerType *PT = LVType->getAs<PointerType>())
3508 LVType = PT->getPointeeType();
3509 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
3510 assert(RD && "member pointer access on non-class-type expression");
3511 // The first class in the path is that of the lvalue.
3512 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
3513 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
3514 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base))
3518 // Finally cast to the class containing the member.
3519 if (!HandleLValueDirectBase(Info, RHS, LV, RD,
3520 MemPtr.getContainingRecord()))
3524 // Add the member. Note that we cannot build bound member functions here.
3525 if (IncludeMember) {
3526 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) {
3527 if (!HandleLValueMember(Info, RHS, LV, FD))
3529 } else if (const IndirectFieldDecl *IFD =
3530 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) {
3531 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD))
3534 llvm_unreachable("can't construct reference to bound member function");
3538 return MemPtr.getDecl();
3541 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
3542 const BinaryOperator *BO,
3544 bool IncludeMember = true) {
3545 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI);
3547 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) {
3548 if (Info.noteFailure()) {
3550 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info);
3555 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV,
3556 BO->getRHS(), IncludeMember);
3559 /// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
3560 /// the provided lvalue, which currently refers to the base object.
3561 static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
3563 SubobjectDesignator &D = Result.Designator;
3564 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
3567 QualType TargetQT = E->getType();
3568 if (const PointerType *PT = TargetQT->getAs<PointerType>())
3569 TargetQT = PT->getPointeeType();
3571 // Check this cast lands within the final derived-to-base subobject path.
3572 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
3573 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
3574 << D.MostDerivedType << TargetQT;
3578 // Check the type of the final cast. We don't need to check the path,
3579 // since a cast can only be formed if the path is unique.
3580 unsigned NewEntriesSize = D.Entries.size() - E->path_size();
3581 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
3582 const CXXRecordDecl *FinalType;
3583 if (NewEntriesSize == D.MostDerivedPathLength)
3584 FinalType = D.MostDerivedType->getAsCXXRecordDecl();
3586 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
3587 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
3588 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
3589 << D.MostDerivedType << TargetQT;
3593 // Truncate the lvalue to the appropriate derived class.
3594 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
3598 enum EvalStmtResult {
3599 /// Evaluation failed.
3601 /// Hit a 'return' statement.
3603 /// Evaluation succeeded.
3605 /// Hit a 'continue' statement.
3607 /// Hit a 'break' statement.
3609 /// Still scanning for 'case' or 'default' statement.
3614 static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
3615 // We don't need to evaluate the initializer for a static local.
3616 if (!VD->hasLocalStorage())
3620 Result.set(VD, Info.CurrentCall->Index);
3621 APValue &Val = Info.CurrentCall->createTemporary(VD, true);
3623 const Expr *InitE = VD->getInit();
3625 Info.FFDiag(VD->getLocStart(), diag::note_constexpr_uninitialized)
3626 << false << VD->getType();
3631 if (InitE->isValueDependent())
3634 if (!EvaluateInPlace(Val, Info, Result, InitE)) {
3635 // Wipe out any partially-computed value, to allow tracking that this
3636 // evaluation failed.
3644 static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
3647 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
3648 OK &= EvaluateVarDecl(Info, VD);
3650 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D))
3651 for (auto *BD : DD->bindings())
3652 if (auto *VD = BD->getHoldingVar())
3653 OK &= EvaluateDecl(Info, VD);
3659 /// Evaluate a condition (either a variable declaration or an expression).
3660 static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
3661 const Expr *Cond, bool &Result) {
3662 FullExpressionRAII Scope(Info);
3663 if (CondDecl && !EvaluateDecl(Info, CondDecl))
3665 return EvaluateAsBooleanCondition(Cond, Result, Info);
3669 /// \brief A location where the result (returned value) of evaluating a
3670 /// statement should be stored.
3672 /// The APValue that should be filled in with the returned value.
3674 /// The location containing the result, if any (used to support RVO).
3679 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
3681 const SwitchCase *SC = nullptr);
3683 /// Evaluate the body of a loop, and translate the result as appropriate.
3684 static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
3686 const SwitchCase *Case = nullptr) {
3687 BlockScopeRAII Scope(Info);
3688 switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case)) {
3690 return ESR_Succeeded;
3693 return ESR_Continue;
3696 case ESR_CaseNotFound:
3699 llvm_unreachable("Invalid EvalStmtResult!");
3702 /// Evaluate a switch statement.
3703 static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
3704 const SwitchStmt *SS) {
3705 BlockScopeRAII Scope(Info);
3707 // Evaluate the switch condition.
3710 FullExpressionRAII Scope(Info);
3711 if (const Stmt *Init = SS->getInit()) {
3712 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
3713 if (ESR != ESR_Succeeded)
3716 if (SS->getConditionVariable() &&
3717 !EvaluateDecl(Info, SS->getConditionVariable()))
3719 if (!EvaluateInteger(SS->getCond(), Value, Info))
3723 // Find the switch case corresponding to the value of the condition.
3724 // FIXME: Cache this lookup.
3725 const SwitchCase *Found = nullptr;
3726 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
3727 SC = SC->getNextSwitchCase()) {
3728 if (isa<DefaultStmt>(SC)) {
3733 const CaseStmt *CS = cast<CaseStmt>(SC);
3734 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx);
3735 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx)
3737 if (LHS <= Value && Value <= RHS) {
3744 return ESR_Succeeded;
3746 // Search the switch body for the switch case and evaluate it from there.
3747 switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found)) {
3749 return ESR_Succeeded;
3755 case ESR_CaseNotFound:
3756 // This can only happen if the switch case is nested within a statement
3757 // expression. We have no intention of supporting that.
3758 Info.FFDiag(Found->getLocStart(), diag::note_constexpr_stmt_expr_unsupported);
3761 llvm_unreachable("Invalid EvalStmtResult!");
3764 // Evaluate a statement.
3765 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
3766 const Stmt *S, const SwitchCase *Case) {
3767 if (!Info.nextStep(S))
3770 // If we're hunting down a 'case' or 'default' label, recurse through
3771 // substatements until we hit the label.
3773 // FIXME: We don't start the lifetime of objects whose initialization we
3774 // jump over. However, such objects must be of class type with a trivial
3775 // default constructor that initialize all subobjects, so must be empty,
3776 // so this almost never matters.
3777 switch (S->getStmtClass()) {
3778 case Stmt::CompoundStmtClass:
3779 // FIXME: Precompute which substatement of a compound statement we
3780 // would jump to, and go straight there rather than performing a
3781 // linear scan each time.
3782 case Stmt::LabelStmtClass:
3783 case Stmt::AttributedStmtClass:
3784 case Stmt::DoStmtClass:
3787 case Stmt::CaseStmtClass:
3788 case Stmt::DefaultStmtClass:
3793 case Stmt::IfStmtClass: {
3794 // FIXME: Precompute which side of an 'if' we would jump to, and go
3795 // straight there rather than scanning both sides.
3796 const IfStmt *IS = cast<IfStmt>(S);
3798 // Wrap the evaluation in a block scope, in case it's a DeclStmt
3799 // preceded by our switch label.
3800 BlockScopeRAII Scope(Info);
3802 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case);
3803 if (ESR != ESR_CaseNotFound || !IS->getElse())
3805 return EvaluateStmt(Result, Info, IS->getElse(), Case);
3808 case Stmt::WhileStmtClass: {
3809 EvalStmtResult ESR =
3810 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case);
3811 if (ESR != ESR_Continue)
3816 case Stmt::ForStmtClass: {
3817 const ForStmt *FS = cast<ForStmt>(S);
3818 EvalStmtResult ESR =
3819 EvaluateLoopBody(Result, Info, FS->getBody(), Case);
3820 if (ESR != ESR_Continue)
3823 FullExpressionRAII IncScope(Info);
3824 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3830 case Stmt::DeclStmtClass:
3831 // FIXME: If the variable has initialization that can't be jumped over,
3832 // bail out of any immediately-surrounding compound-statement too.
3834 return ESR_CaseNotFound;
3838 switch (S->getStmtClass()) {
3840 if (const Expr *E = dyn_cast<Expr>(S)) {
3841 // Don't bother evaluating beyond an expression-statement which couldn't
3843 FullExpressionRAII Scope(Info);
3844 if (!EvaluateIgnoredValue(Info, E))
3846 return ESR_Succeeded;
3849 Info.FFDiag(S->getLocStart());
3852 case Stmt::NullStmtClass:
3853 return ESR_Succeeded;
3855 case Stmt::DeclStmtClass: {
3856 const DeclStmt *DS = cast<DeclStmt>(S);
3857 for (const auto *DclIt : DS->decls()) {
3858 // Each declaration initialization is its own full-expression.
3859 // FIXME: This isn't quite right; if we're performing aggregate
3860 // initialization, each braced subexpression is its own full-expression.
3861 FullExpressionRAII Scope(Info);
3862 if (!EvaluateDecl(Info, DclIt) && !Info.noteFailure())
3865 return ESR_Succeeded;
3868 case Stmt::ReturnStmtClass: {
3869 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
3870 FullExpressionRAII Scope(Info);
3873 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr)
3874 : Evaluate(Result.Value, Info, RetExpr)))
3876 return ESR_Returned;
3879 case Stmt::CompoundStmtClass: {
3880 BlockScopeRAII Scope(Info);
3882 const CompoundStmt *CS = cast<CompoundStmt>(S);
3883 for (const auto *BI : CS->body()) {
3884 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case);
3885 if (ESR == ESR_Succeeded)
3887 else if (ESR != ESR_CaseNotFound)
3890 return Case ? ESR_CaseNotFound : ESR_Succeeded;
3893 case Stmt::IfStmtClass: {
3894 const IfStmt *IS = cast<IfStmt>(S);
3896 // Evaluate the condition, as either a var decl or as an expression.
3897 BlockScopeRAII Scope(Info);
3898 if (const Stmt *Init = IS->getInit()) {
3899 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
3900 if (ESR != ESR_Succeeded)
3904 if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
3907 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
3908 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
3909 if (ESR != ESR_Succeeded)
3912 return ESR_Succeeded;
3915 case Stmt::WhileStmtClass: {
3916 const WhileStmt *WS = cast<WhileStmt>(S);
3918 BlockScopeRAII Scope(Info);
3920 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
3926 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
3927 if (ESR != ESR_Continue)
3930 return ESR_Succeeded;
3933 case Stmt::DoStmtClass: {
3934 const DoStmt *DS = cast<DoStmt>(S);
3937 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case);
3938 if (ESR != ESR_Continue)
3942 FullExpressionRAII CondScope(Info);
3943 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info))
3946 return ESR_Succeeded;
3949 case Stmt::ForStmtClass: {
3950 const ForStmt *FS = cast<ForStmt>(S);
3951 BlockScopeRAII Scope(Info);
3952 if (FS->getInit()) {
3953 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
3954 if (ESR != ESR_Succeeded)
3958 BlockScopeRAII Scope(Info);
3959 bool Continue = true;
3960 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
3961 FS->getCond(), Continue))
3966 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
3967 if (ESR != ESR_Continue)
3971 FullExpressionRAII IncScope(Info);
3972 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3976 return ESR_Succeeded;
3979 case Stmt::CXXForRangeStmtClass: {
3980 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S);
3981 BlockScopeRAII Scope(Info);
3983 // Initialize the __range variable.
3984 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt());
3985 if (ESR != ESR_Succeeded)
3988 // Create the __begin and __end iterators.
3989 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt());
3990 if (ESR != ESR_Succeeded)
3992 ESR = EvaluateStmt(Result, Info, FS->getEndStmt());
3993 if (ESR != ESR_Succeeded)
3997 // Condition: __begin != __end.
3999 bool Continue = true;
4000 FullExpressionRAII CondExpr(Info);
4001 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info))
4007 // User's variable declaration, initialized by *__begin.
4008 BlockScopeRAII InnerScope(Info);
4009 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt());
4010 if (ESR != ESR_Succeeded)
4014 ESR = EvaluateLoopBody(Result, Info, FS->getBody());
4015 if (ESR != ESR_Continue)
4018 // Increment: ++__begin
4019 if (!EvaluateIgnoredValue(Info, FS->getInc()))
4023 return ESR_Succeeded;
4026 case Stmt::SwitchStmtClass:
4027 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S));
4029 case Stmt::ContinueStmtClass:
4030 return ESR_Continue;
4032 case Stmt::BreakStmtClass:
4035 case Stmt::LabelStmtClass:
4036 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case);
4038 case Stmt::AttributedStmtClass:
4039 // As a general principle, C++11 attributes can be ignored without
4040 // any semantic impact.
4041 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(),
4044 case Stmt::CaseStmtClass:
4045 case Stmt::DefaultStmtClass:
4046 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case);
4050 /// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
4051 /// default constructor. If so, we'll fold it whether or not it's marked as
4052 /// constexpr. If it is marked as constexpr, we will never implicitly define it,
4053 /// so we need special handling.
4054 static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
4055 const CXXConstructorDecl *CD,
4056 bool IsValueInitialization) {
4057 if (!CD->isTrivial() || !CD->isDefaultConstructor())
4060 // Value-initialization does not call a trivial default constructor, so such a
4061 // call is a core constant expression whether or not the constructor is
4063 if (!CD->isConstexpr() && !IsValueInitialization) {
4064 if (Info.getLangOpts().CPlusPlus11) {
4065 // FIXME: If DiagDecl is an implicitly-declared special member function,
4066 // we should be much more explicit about why it's not constexpr.
4067 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
4068 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
4069 Info.Note(CD->getLocation(), diag::note_declared_at);
4071 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
4077 /// CheckConstexprFunction - Check that a function can be called in a constant
4079 static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
4080 const FunctionDecl *Declaration,
4081 const FunctionDecl *Definition,
4083 // Potential constant expressions can contain calls to declared, but not yet
4084 // defined, constexpr functions.
4085 if (Info.checkingPotentialConstantExpression() && !Definition &&
4086 Declaration->isConstexpr())
4089 // Bail out with no diagnostic if the function declaration itself is invalid.
4090 // We will have produced a relevant diagnostic while parsing it.
4091 if (Declaration->isInvalidDecl())
4094 // Can we evaluate this function call?
4095 if (Definition && Definition->isConstexpr() &&
4096 !Definition->isInvalidDecl() && Body)
4099 if (Info.getLangOpts().CPlusPlus11) {
4100 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
4102 // If this function is not constexpr because it is an inherited
4103 // non-constexpr constructor, diagnose that directly.
4104 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
4105 if (CD && CD->isInheritingConstructor()) {
4106 auto *Inherited = CD->getInheritedConstructor().getConstructor();
4107 if (!Inherited->isConstexpr())
4108 DiagDecl = CD = Inherited;
4111 // FIXME: If DiagDecl is an implicitly-declared special member function
4112 // or an inheriting constructor, we should be much more explicit about why
4113 // it's not constexpr.
4114 if (CD && CD->isInheritingConstructor())
4115 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
4116 << CD->getInheritedConstructor().getConstructor()->getParent();
4118 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
4119 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
4120 Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
4122 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
4127 /// Determine if a class has any fields that might need to be copied by a
4128 /// trivial copy or move operation.
4129 static bool hasFields(const CXXRecordDecl *RD) {
4130 if (!RD || RD->isEmpty())
4132 for (auto *FD : RD->fields()) {
4133 if (FD->isUnnamedBitfield())
4137 for (auto &Base : RD->bases())
4138 if (hasFields(Base.getType()->getAsCXXRecordDecl()))
4144 typedef SmallVector<APValue, 8> ArgVector;
4147 /// EvaluateArgs - Evaluate the arguments to a function call.
4148 static bool EvaluateArgs(ArrayRef<const Expr*> Args, ArgVector &ArgValues,
4150 bool Success = true;
4151 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
4153 if (!Evaluate(ArgValues[I - Args.begin()], Info, *I)) {
4154 // If we're checking for a potential constant expression, evaluate all
4155 // initializers even if some of them fail.
4156 if (!Info.noteFailure())
4164 /// Evaluate a function call.
4165 static bool HandleFunctionCall(SourceLocation CallLoc,
4166 const FunctionDecl *Callee, const LValue *This,
4167 ArrayRef<const Expr*> Args, const Stmt *Body,
4168 EvalInfo &Info, APValue &Result,
4169 const LValue *ResultSlot) {
4170 ArgVector ArgValues(Args.size());
4171 if (!EvaluateArgs(Args, ArgValues, Info))
4174 if (!Info.CheckCallLimit(CallLoc))
4177 CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data());
4179 // For a trivial copy or move assignment, perform an APValue copy. This is
4180 // essential for unions, where the operations performed by the assignment
4181 // operator cannot be represented as statements.
4183 // Skip this for non-union classes with no fields; in that case, the defaulted
4184 // copy/move does not actually read the object.
4185 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee);
4186 if (MD && MD->isDefaulted() &&
4187 (MD->getParent()->isUnion() ||
4188 (MD->isTrivial() && hasFields(MD->getParent())))) {
4190 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()));
4192 RHS.setFrom(Info.Ctx, ArgValues[0]);
4194 if (!handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(),
4197 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(Info.Ctx),
4200 This->moveInto(Result);
4202 } else if (MD && isLambdaCallOperator(MD)) {
4203 // We're in a lambda; determine the lambda capture field maps.
4204 MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields,
4205 Frame.LambdaThisCaptureField);
4208 StmtResult Ret = {Result, ResultSlot};
4209 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body);
4210 if (ESR == ESR_Succeeded) {
4211 if (Callee->getReturnType()->isVoidType())
4213 Info.FFDiag(Callee->getLocEnd(), diag::note_constexpr_no_return);
4215 return ESR == ESR_Returned;
4218 /// Evaluate a constructor call.
4219 static bool HandleConstructorCall(const Expr *E, const LValue &This,
4221 const CXXConstructorDecl *Definition,
4222 EvalInfo &Info, APValue &Result) {
4223 SourceLocation CallLoc = E->getExprLoc();
4224 if (!Info.CheckCallLimit(CallLoc))
4227 const CXXRecordDecl *RD = Definition->getParent();
4228 if (RD->getNumVBases()) {
4229 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
4233 CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues);
4235 // FIXME: Creating an APValue just to hold a nonexistent return value is
4238 StmtResult Ret = {RetVal, nullptr};
4240 // If it's a delegating constructor, delegate.
4241 if (Definition->isDelegatingConstructor()) {
4242 CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
4244 FullExpressionRAII InitScope(Info);
4245 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()))
4248 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
4251 // For a trivial copy or move constructor, perform an APValue copy. This is
4252 // essential for unions (or classes with anonymous union members), where the
4253 // operations performed by the constructor cannot be represented by
4254 // ctor-initializers.
4256 // Skip this for empty non-union classes; we should not perform an
4257 // lvalue-to-rvalue conversion on them because their copy constructor does not
4258 // actually read them.
4259 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
4260 (Definition->getParent()->isUnion() ||
4261 (Definition->isTrivial() && hasFields(Definition->getParent())))) {
4263 RHS.setFrom(Info.Ctx, ArgValues[0]);
4264 return handleLValueToRValueConversion(
4265 Info, E, Definition->getParamDecl(0)->getType().getNonReferenceType(),
4269 // Reserve space for the struct members.
4270 if (!RD->isUnion() && Result.isUninit())
4271 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
4272 std::distance(RD->field_begin(), RD->field_end()));
4274 if (RD->isInvalidDecl()) return false;
4275 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
4277 // A scope for temporaries lifetime-extended by reference members.
4278 BlockScopeRAII LifetimeExtendedScope(Info);
4280 bool Success = true;
4281 unsigned BasesSeen = 0;
4283 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
4285 for (const auto *I : Definition->inits()) {
4286 LValue Subobject = This;
4287 APValue *Value = &Result;
4289 // Determine the subobject to initialize.
4290 FieldDecl *FD = nullptr;
4291 if (I->isBaseInitializer()) {
4292 QualType BaseType(I->getBaseClass(), 0);
4294 // Non-virtual base classes are initialized in the order in the class
4295 // definition. We have already checked for virtual base classes.
4296 assert(!BaseIt->isVirtual() && "virtual base for literal type");
4297 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
4298 "base class initializers not in expected order");
4301 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD,
4302 BaseType->getAsCXXRecordDecl(), &Layout))
4304 Value = &Result.getStructBase(BasesSeen++);
4305 } else if ((FD = I->getMember())) {
4306 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout))
4308 if (RD->isUnion()) {
4309 Result = APValue(FD);
4310 Value = &Result.getUnionValue();
4312 Value = &Result.getStructField(FD->getFieldIndex());
4314 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
4315 // Walk the indirect field decl's chain to find the object to initialize,
4316 // and make sure we've initialized every step along it.
4317 for (auto *C : IFD->chain()) {
4318 FD = cast<FieldDecl>(C);
4319 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
4320 // Switch the union field if it differs. This happens if we had
4321 // preceding zero-initialization, and we're now initializing a union
4322 // subobject other than the first.
4323 // FIXME: In this case, the values of the other subobjects are
4324 // specified, since zero-initialization sets all padding bits to zero.
4325 if (Value->isUninit() ||
4326 (Value->isUnion() && Value->getUnionField() != FD)) {
4328 *Value = APValue(FD);
4330 *Value = APValue(APValue::UninitStruct(), CD->getNumBases(),
4331 std::distance(CD->field_begin(), CD->field_end()));
4333 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
4336 Value = &Value->getUnionValue();
4338 Value = &Value->getStructField(FD->getFieldIndex());
4341 llvm_unreachable("unknown base initializer kind");
4344 FullExpressionRAII InitScope(Info);
4345 if (!EvaluateInPlace(*Value, Info, Subobject, I->getInit()) ||
4346 (FD && FD->isBitField() && !truncateBitfieldValue(Info, I->getInit(),
4348 // If we're checking for a potential constant expression, evaluate all
4349 // initializers even if some of them fail.
4350 if (!Info.noteFailure())
4357 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
4360 static bool HandleConstructorCall(const Expr *E, const LValue &This,
4361 ArrayRef<const Expr*> Args,
4362 const CXXConstructorDecl *Definition,
4363 EvalInfo &Info, APValue &Result) {
4364 ArgVector ArgValues(Args.size());
4365 if (!EvaluateArgs(Args, ArgValues, Info))
4368 return HandleConstructorCall(E, This, ArgValues.data(), Definition,
4372 //===----------------------------------------------------------------------===//
4373 // Generic Evaluation
4374 //===----------------------------------------------------------------------===//
4377 template <class Derived>
4378 class ExprEvaluatorBase
4379 : public ConstStmtVisitor<Derived, bool> {
4381 Derived &getDerived() { return static_cast<Derived&>(*this); }
4382 bool DerivedSuccess(const APValue &V, const Expr *E) {
4383 return getDerived().Success(V, E);
4385 bool DerivedZeroInitialization(const Expr *E) {
4386 return getDerived().ZeroInitialization(E);
4389 // Check whether a conditional operator with a non-constant condition is a
4390 // potential constant expression. If neither arm is a potential constant
4391 // expression, then the conditional operator is not either.
4392 template<typename ConditionalOperator>
4393 void CheckPotentialConstantConditional(const ConditionalOperator *E) {
4394 assert(Info.checkingPotentialConstantExpression());
4396 // Speculatively evaluate both arms.
4397 SmallVector<PartialDiagnosticAt, 8> Diag;
4399 SpeculativeEvaluationRAII Speculate(Info, &Diag);
4400 StmtVisitorTy::Visit(E->getFalseExpr());
4406 SpeculativeEvaluationRAII Speculate(Info, &Diag);
4408 StmtVisitorTy::Visit(E->getTrueExpr());
4413 Error(E, diag::note_constexpr_conditional_never_const);
4417 template<typename ConditionalOperator>
4418 bool HandleConditionalOperator(const ConditionalOperator *E) {
4420 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
4421 if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) {
4422 CheckPotentialConstantConditional(E);
4425 if (Info.noteFailure()) {
4426 StmtVisitorTy::Visit(E->getTrueExpr());
4427 StmtVisitorTy::Visit(E->getFalseExpr());
4432 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
4433 return StmtVisitorTy::Visit(EvalExpr);
4438 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
4439 typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
4441 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
4442 return Info.CCEDiag(E, D);
4445 bool ZeroInitialization(const Expr *E) { return Error(E); }
4448 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
4450 EvalInfo &getEvalInfo() { return Info; }
4452 /// Report an evaluation error. This should only be called when an error is
4453 /// first discovered. When propagating an error, just return false.
4454 bool Error(const Expr *E, diag::kind D) {
4458 bool Error(const Expr *E) {
4459 return Error(E, diag::note_invalid_subexpr_in_const_expr);
4462 bool VisitStmt(const Stmt *) {
4463 llvm_unreachable("Expression evaluator should not be called on stmts");
4465 bool VisitExpr(const Expr *E) {
4469 bool VisitParenExpr(const ParenExpr *E)
4470 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4471 bool VisitUnaryExtension(const UnaryOperator *E)
4472 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4473 bool VisitUnaryPlus(const UnaryOperator *E)
4474 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4475 bool VisitChooseExpr(const ChooseExpr *E)
4476 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
4477 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
4478 { return StmtVisitorTy::Visit(E->getResultExpr()); }
4479 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
4480 { return StmtVisitorTy::Visit(E->getReplacement()); }
4481 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E)
4482 { return StmtVisitorTy::Visit(E->getExpr()); }
4483 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
4484 // The initializer may not have been parsed yet, or might be erroneous.
4487 return StmtVisitorTy::Visit(E->getExpr());
4489 // We cannot create any objects for which cleanups are required, so there is
4490 // nothing to do here; all cleanups must come from unevaluated subexpressions.
4491 bool VisitExprWithCleanups(const ExprWithCleanups *E)
4492 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4494 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
4495 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
4496 return static_cast<Derived*>(this)->VisitCastExpr(E);
4498 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
4499 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
4500 return static_cast<Derived*>(this)->VisitCastExpr(E);
4503 bool VisitBinaryOperator(const BinaryOperator *E) {
4504 switch (E->getOpcode()) {
4509 VisitIgnoredValue(E->getLHS());
4510 return StmtVisitorTy::Visit(E->getRHS());
4515 if (!HandleMemberPointerAccess(Info, E, Obj))
4518 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
4520 return DerivedSuccess(Result, E);
4525 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
4526 // Evaluate and cache the common expression. We treat it as a temporary,
4527 // even though it's not quite the same thing.
4528 if (!Evaluate(Info.CurrentCall->createTemporary(E->getOpaqueValue(), false),
4529 Info, E->getCommon()))
4532 return HandleConditionalOperator(E);
4535 bool VisitConditionalOperator(const ConditionalOperator *E) {
4536 bool IsBcpCall = false;
4537 // If the condition (ignoring parens) is a __builtin_constant_p call,
4538 // the result is a constant expression if it can be folded without
4539 // side-effects. This is an important GNU extension. See GCC PR38377
4541 if (const CallExpr *CallCE =
4542 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
4543 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
4546 // Always assume __builtin_constant_p(...) ? ... : ... is a potential
4547 // constant expression; we can't check whether it's potentially foldable.
4548 if (Info.checkingPotentialConstantExpression() && IsBcpCall)
4551 FoldConstant Fold(Info, IsBcpCall);
4552 if (!HandleConditionalOperator(E)) {
4553 Fold.keepDiagnostics();
4560 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
4561 if (APValue *Value = Info.CurrentCall->getTemporary(E))
4562 return DerivedSuccess(*Value, E);
4564 const Expr *Source = E->getSourceExpr();
4567 if (Source == E) { // sanity checking.
4568 assert(0 && "OpaqueValueExpr recursively refers to itself");
4571 return StmtVisitorTy::Visit(Source);
4574 bool VisitCallExpr(const CallExpr *E) {
4576 if (!handleCallExpr(E, Result, nullptr))
4578 return DerivedSuccess(Result, E);
4581 bool handleCallExpr(const CallExpr *E, APValue &Result,
4582 const LValue *ResultSlot) {
4583 const Expr *Callee = E->getCallee()->IgnoreParens();
4584 QualType CalleeType = Callee->getType();
4586 const FunctionDecl *FD = nullptr;
4587 LValue *This = nullptr, ThisVal;
4588 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
4589 bool HasQualifier = false;
4591 // Extract function decl and 'this' pointer from the callee.
4592 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
4593 const ValueDecl *Member = nullptr;
4594 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
4595 // Explicit bound member calls, such as x.f() or p->g();
4596 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
4598 Member = ME->getMemberDecl();
4600 HasQualifier = ME->hasQualifier();
4601 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
4602 // Indirect bound member calls ('.*' or '->*').
4603 Member = HandleMemberPointerAccess(Info, BE, ThisVal, false);
4604 if (!Member) return false;
4607 return Error(Callee);
4609 FD = dyn_cast<FunctionDecl>(Member);
4611 return Error(Callee);
4612 } else if (CalleeType->isFunctionPointerType()) {
4614 if (!EvaluatePointer(Callee, Call, Info))
4617 if (!Call.getLValueOffset().isZero())
4618 return Error(Callee);
4619 FD = dyn_cast_or_null<FunctionDecl>(
4620 Call.getLValueBase().dyn_cast<const ValueDecl*>());
4622 return Error(Callee);
4623 // Don't call function pointers which have been cast to some other type.
4624 // Per DR (no number yet), the caller and callee can differ in noexcept.
4625 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
4626 CalleeType->getPointeeType(), FD->getType())) {
4630 // Overloaded operator calls to member functions are represented as normal
4631 // calls with '*this' as the first argument.
4632 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
4633 if (MD && !MD->isStatic()) {
4634 // FIXME: When selecting an implicit conversion for an overloaded
4635 // operator delete, we sometimes try to evaluate calls to conversion
4636 // operators without a 'this' parameter!
4640 if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
4643 Args = Args.slice(1);
4644 } else if (MD && MD->isLambdaStaticInvoker()) {
4645 // Map the static invoker for the lambda back to the call operator.
4646 // Conveniently, we don't have to slice out the 'this' argument (as is
4647 // being done for the non-static case), since a static member function
4648 // doesn't have an implicit argument passed in.
4649 const CXXRecordDecl *ClosureClass = MD->getParent();
4651 ClosureClass->captures_begin() == ClosureClass->captures_end() &&
4652 "Number of captures must be zero for conversion to function-ptr");
4654 const CXXMethodDecl *LambdaCallOp =
4655 ClosureClass->getLambdaCallOperator();
4657 // Set 'FD', the function that will be called below, to the call
4658 // operator. If the closure object represents a generic lambda, find
4659 // the corresponding specialization of the call operator.
4661 if (ClosureClass->isGenericLambda()) {
4662 assert(MD->isFunctionTemplateSpecialization() &&
4663 "A generic lambda's static-invoker function must be a "
4664 "template specialization");
4665 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
4666 FunctionTemplateDecl *CallOpTemplate =
4667 LambdaCallOp->getDescribedFunctionTemplate();
4668 void *InsertPos = nullptr;
4669 FunctionDecl *CorrespondingCallOpSpecialization =
4670 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
4671 assert(CorrespondingCallOpSpecialization &&
4672 "We must always have a function call operator specialization "
4673 "that corresponds to our static invoker specialization");
4674 FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
4683 if (This && !This->checkSubobject(Info, E, CSK_This))
4686 // DR1358 allows virtual constexpr functions in some cases. Don't allow
4687 // calls to such functions in constant expressions.
4688 if (This && !HasQualifier &&
4689 isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isVirtual())
4690 return Error(E, diag::note_constexpr_virtual_call);
4692 const FunctionDecl *Definition = nullptr;
4693 Stmt *Body = FD->getBody(Definition);
4695 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
4696 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, Info,
4697 Result, ResultSlot))
4703 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
4704 return StmtVisitorTy::Visit(E->getInitializer());
4706 bool VisitInitListExpr(const InitListExpr *E) {
4707 if (E->getNumInits() == 0)
4708 return DerivedZeroInitialization(E);
4709 if (E->getNumInits() == 1)
4710 return StmtVisitorTy::Visit(E->getInit(0));
4713 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
4714 return DerivedZeroInitialization(E);
4716 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
4717 return DerivedZeroInitialization(E);
4719 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
4720 return DerivedZeroInitialization(E);
4723 /// A member expression where the object is a prvalue is itself a prvalue.
4724 bool VisitMemberExpr(const MemberExpr *E) {
4725 assert(!E->isArrow() && "missing call to bound member function?");
4728 if (!Evaluate(Val, Info, E->getBase()))
4731 QualType BaseTy = E->getBase()->getType();
4733 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
4734 if (!FD) return Error(E);
4735 assert(!FD->getType()->isReferenceType() && "prvalue reference?");
4736 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
4737 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
4739 CompleteObject Obj(&Val, BaseTy);
4740 SubobjectDesignator Designator(BaseTy);
4741 Designator.addDeclUnchecked(FD);
4744 return extractSubobject(Info, E, Obj, Designator, Result) &&
4745 DerivedSuccess(Result, E);
4748 bool VisitCastExpr(const CastExpr *E) {
4749 switch (E->getCastKind()) {
4753 case CK_AtomicToNonAtomic: {
4755 // This does not need to be done in place even for class/array types:
4756 // atomic-to-non-atomic conversion implies copying the object
4758 if (!Evaluate(AtomicVal, Info, E->getSubExpr()))
4760 return DerivedSuccess(AtomicVal, E);
4764 case CK_UserDefinedConversion:
4765 return StmtVisitorTy::Visit(E->getSubExpr());
4767 case CK_LValueToRValue: {
4769 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
4772 // Note, we use the subexpression's type in order to retain cv-qualifiers.
4773 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
4776 return DerivedSuccess(RVal, E);
4783 bool VisitUnaryPostInc(const UnaryOperator *UO) {
4784 return VisitUnaryPostIncDec(UO);
4786 bool VisitUnaryPostDec(const UnaryOperator *UO) {
4787 return VisitUnaryPostIncDec(UO);
4789 bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
4790 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
4794 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info))
4797 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
4798 UO->isIncrementOp(), &RVal))
4800 return DerivedSuccess(RVal, UO);
4803 bool VisitStmtExpr(const StmtExpr *E) {
4804 // We will have checked the full-expressions inside the statement expression
4805 // when they were completed, and don't need to check them again now.
4806 if (Info.checkingForOverflow())
4809 BlockScopeRAII Scope(Info);
4810 const CompoundStmt *CS = E->getSubStmt();
4811 if (CS->body_empty())
4814 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
4815 BE = CS->body_end();
4818 const Expr *FinalExpr = dyn_cast<Expr>(*BI);
4820 Info.FFDiag((*BI)->getLocStart(),
4821 diag::note_constexpr_stmt_expr_unsupported);
4824 return this->Visit(FinalExpr);
4827 APValue ReturnValue;
4828 StmtResult Result = { ReturnValue, nullptr };
4829 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
4830 if (ESR != ESR_Succeeded) {
4831 // FIXME: If the statement-expression terminated due to 'return',
4832 // 'break', or 'continue', it would be nice to propagate that to
4833 // the outer statement evaluation rather than bailing out.
4834 if (ESR != ESR_Failed)
4835 Info.FFDiag((*BI)->getLocStart(),
4836 diag::note_constexpr_stmt_expr_unsupported);
4841 llvm_unreachable("Return from function from the loop above.");
4844 /// Visit a value which is evaluated, but whose value is ignored.
4845 void VisitIgnoredValue(const Expr *E) {
4846 EvaluateIgnoredValue(Info, E);
4849 /// Potentially visit a MemberExpr's base expression.
4850 void VisitIgnoredBaseExpression(const Expr *E) {
4851 // While MSVC doesn't evaluate the base expression, it does diagnose the
4852 // presence of side-effecting behavior.
4853 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
4855 VisitIgnoredValue(E);
4861 //===----------------------------------------------------------------------===//
4862 // Common base class for lvalue and temporary evaluation.
4863 //===----------------------------------------------------------------------===//
4865 template<class Derived>
4866 class LValueExprEvaluatorBase
4867 : public ExprEvaluatorBase<Derived> {
4871 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
4872 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
4874 bool Success(APValue::LValueBase B) {
4879 bool evaluatePointer(const Expr *E, LValue &Result) {
4880 return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
4884 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
4885 : ExprEvaluatorBaseTy(Info), Result(Result),
4886 InvalidBaseOK(InvalidBaseOK) {}
4888 bool Success(const APValue &V, const Expr *E) {
4889 Result.setFrom(this->Info.Ctx, V);
4893 bool VisitMemberExpr(const MemberExpr *E) {
4894 // Handle non-static data members.
4898 EvalOK = evaluatePointer(E->getBase(), Result);
4899 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
4900 } else if (E->getBase()->isRValue()) {
4901 assert(E->getBase()->getType()->isRecordType());
4902 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
4903 BaseTy = E->getBase()->getType();
4905 EvalOK = this->Visit(E->getBase());
4906 BaseTy = E->getBase()->getType();
4911 Result.setInvalid(E);
4915 const ValueDecl *MD = E->getMemberDecl();
4916 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
4917 assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() ==
4918 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
4920 if (!HandleLValueMember(this->Info, E, Result, FD))
4922 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
4923 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
4926 return this->Error(E);
4928 if (MD->getType()->isReferenceType()) {
4930 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
4933 return Success(RefValue, E);
4938 bool VisitBinaryOperator(const BinaryOperator *E) {
4939 switch (E->getOpcode()) {
4941 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
4945 return HandleMemberPointerAccess(this->Info, E, Result);
4949 bool VisitCastExpr(const CastExpr *E) {
4950 switch (E->getCastKind()) {
4952 return ExprEvaluatorBaseTy::VisitCastExpr(E);
4954 case CK_DerivedToBase:
4955 case CK_UncheckedDerivedToBase:
4956 if (!this->Visit(E->getSubExpr()))
4959 // Now figure out the necessary offset to add to the base LV to get from
4960 // the derived class to the base class.
4961 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
4968 //===----------------------------------------------------------------------===//
4969 // LValue Evaluation
4971 // This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
4972 // function designators (in C), decl references to void objects (in C), and
4973 // temporaries (if building with -Wno-address-of-temporary).
4975 // LValue evaluation produces values comprising a base expression of one of the
4981 // * CompoundLiteralExpr in C (and in global scope in C++)
4985 // * ObjCStringLiteralExpr
4989 // * CallExpr for a MakeStringConstant builtin
4990 // - Locals and temporaries
4991 // * MaterializeTemporaryExpr
4992 // * Any Expr, with a CallIndex indicating the function in which the temporary
4993 // was evaluated, for cases where the MaterializeTemporaryExpr is missing
4994 // from the AST (FIXME).
4995 // * A MaterializeTemporaryExpr that has static storage duration, with no
4996 // CallIndex, for a lifetime-extended temporary.
4997 // plus an offset in bytes.
4998 //===----------------------------------------------------------------------===//
5000 class LValueExprEvaluator
5001 : public LValueExprEvaluatorBase<LValueExprEvaluator> {
5003 LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
5004 LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}
5006 bool VisitVarDecl(const Expr *E, const VarDecl *VD);
5007 bool VisitUnaryPreIncDec(const UnaryOperator *UO);
5009 bool VisitDeclRefExpr(const DeclRefExpr *E);
5010 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
5011 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
5012 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
5013 bool VisitMemberExpr(const MemberExpr *E);
5014 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
5015 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
5016 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
5017 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
5018 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
5019 bool VisitUnaryDeref(const UnaryOperator *E);
5020 bool VisitUnaryReal(const UnaryOperator *E);
5021 bool VisitUnaryImag(const UnaryOperator *E);
5022 bool VisitUnaryPreInc(const UnaryOperator *UO) {
5023 return VisitUnaryPreIncDec(UO);
5025 bool VisitUnaryPreDec(const UnaryOperator *UO) {
5026 return VisitUnaryPreIncDec(UO);
5028 bool VisitBinAssign(const BinaryOperator *BO);
5029 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
5031 bool VisitCastExpr(const CastExpr *E) {
5032 switch (E->getCastKind()) {
5034 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
5036 case CK_LValueBitCast:
5037 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5038 if (!Visit(E->getSubExpr()))
5040 Result.Designator.setInvalid();
5043 case CK_BaseToDerived:
5044 if (!Visit(E->getSubExpr()))
5046 return HandleBaseToDerivedCast(Info, E, Result);
5050 } // end anonymous namespace
5052 /// Evaluate an expression as an lvalue. This can be legitimately called on
5053 /// expressions which are not glvalues, in three cases:
5054 /// * function designators in C, and
5055 /// * "extern void" objects
5056 /// * @selector() expressions in Objective-C
5057 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
5058 bool InvalidBaseOK) {
5059 assert(E->isGLValue() || E->getType()->isFunctionType() ||
5060 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E));
5061 return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
5064 bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
5065 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl()))
5067 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
5068 return VisitVarDecl(E, VD);
5069 if (const BindingDecl *BD = dyn_cast<BindingDecl>(E->getDecl()))
5070 return Visit(BD->getBinding());
5075 bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
5077 // If we are within a lambda's call operator, check whether the 'VD' referred
5078 // to within 'E' actually represents a lambda-capture that maps to a
5079 // data-member/field within the closure object, and if so, evaluate to the
5080 // field or what the field refers to.
5081 if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee)) {
5082 if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) {
5083 if (Info.checkingPotentialConstantExpression())
5085 // Start with 'Result' referring to the complete closure object...
5086 Result = *Info.CurrentCall->This;
5087 // ... then update it to refer to the field of the closure object
5088 // that represents the capture.
5089 if (!HandleLValueMember(Info, E, Result, FD))
5091 // And if the field is of reference type, update 'Result' to refer to what
5092 // the field refers to.
5093 if (FD->getType()->isReferenceType()) {
5095 if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result,
5098 Result.setFrom(Info.Ctx, RVal);
5103 CallStackFrame *Frame = nullptr;
5104 if (VD->hasLocalStorage() && Info.CurrentCall->Index > 1) {
5105 // Only if a local variable was declared in the function currently being
5106 // evaluated, do we expect to be able to find its value in the current
5107 // frame. (Otherwise it was likely declared in an enclosing context and
5108 // could either have a valid evaluatable value (for e.g. a constexpr
5109 // variable) or be ill-formed (and trigger an appropriate evaluation
5111 if (Info.CurrentCall->Callee &&
5112 Info.CurrentCall->Callee->Equals(VD->getDeclContext())) {
5113 Frame = Info.CurrentCall;
5117 if (!VD->getType()->isReferenceType()) {
5119 Result.set(VD, Frame->Index);
5126 if (!evaluateVarDeclInit(Info, E, VD, Frame, V))
5128 if (V->isUninit()) {
5129 if (!Info.checkingPotentialConstantExpression())
5130 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
5133 return Success(*V, E);
5136 bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
5137 const MaterializeTemporaryExpr *E) {
5138 // Walk through the expression to find the materialized temporary itself.
5139 SmallVector<const Expr *, 2> CommaLHSs;
5140 SmallVector<SubobjectAdjustment, 2> Adjustments;
5141 const Expr *Inner = E->GetTemporaryExpr()->
5142 skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
5144 // If we passed any comma operators, evaluate their LHSs.
5145 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
5146 if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
5149 // A materialized temporary with static storage duration can appear within the
5150 // result of a constant expression evaluation, so we need to preserve its
5151 // value for use outside this evaluation.
5153 if (E->getStorageDuration() == SD_Static) {
5154 Value = Info.Ctx.getMaterializedTemporaryValue(E, true);
5158 Value = &Info.CurrentCall->
5159 createTemporary(E, E->getStorageDuration() == SD_Automatic);
5160 Result.set(E, Info.CurrentCall->Index);
5163 QualType Type = Inner->getType();
5165 // Materialize the temporary itself.
5166 if (!EvaluateInPlace(*Value, Info, Result, Inner) ||
5167 (E->getStorageDuration() == SD_Static &&
5168 !CheckConstantExpression(Info, E->getExprLoc(), Type, *Value))) {
5173 // Adjust our lvalue to refer to the desired subobject.
5174 for (unsigned I = Adjustments.size(); I != 0; /**/) {
5176 switch (Adjustments[I].Kind) {
5177 case SubobjectAdjustment::DerivedToBaseAdjustment:
5178 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath,
5181 Type = Adjustments[I].DerivedToBase.BasePath->getType();
5184 case SubobjectAdjustment::FieldAdjustment:
5185 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
5187 Type = Adjustments[I].Field->getType();
5190 case SubobjectAdjustment::MemberPointerAdjustment:
5191 if (!HandleMemberPointerAccess(this->Info, Type, Result,
5192 Adjustments[I].Ptr.RHS))
5194 Type = Adjustments[I].Ptr.MPT->getPointeeType();
5203 LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
5204 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
5205 "lvalue compound literal in c++?");
5206 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
5207 // only see this when folding in C, so there's no standard to follow here.
5211 bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
5212 if (!E->isPotentiallyEvaluated())
5215 Info.FFDiag(E, diag::note_constexpr_typeid_polymorphic)
5216 << E->getExprOperand()->getType()
5217 << E->getExprOperand()->getSourceRange();
5221 bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
5225 bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
5226 // Handle static data members.
5227 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
5228 VisitIgnoredBaseExpression(E->getBase());
5229 return VisitVarDecl(E, VD);
5232 // Handle static member functions.
5233 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
5234 if (MD->isStatic()) {
5235 VisitIgnoredBaseExpression(E->getBase());
5240 // Handle non-static data members.
5241 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
5244 bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
5245 // FIXME: Deal with vectors as array subscript bases.
5246 if (E->getBase()->getType()->isVectorType())
5249 bool Success = true;
5250 if (!evaluatePointer(E->getBase(), Result)) {
5251 if (!Info.noteFailure())
5257 if (!EvaluateInteger(E->getIdx(), Index, Info))
5261 HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index);
5264 bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
5265 return evaluatePointer(E->getSubExpr(), Result);
5268 bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
5269 if (!Visit(E->getSubExpr()))
5271 // __real is a no-op on scalar lvalues.
5272 if (E->getSubExpr()->getType()->isAnyComplexType())
5273 HandleLValueComplexElement(Info, E, Result, E->getType(), false);
5277 bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
5278 assert(E->getSubExpr()->getType()->isAnyComplexType() &&
5279 "lvalue __imag__ on scalar?");
5280 if (!Visit(E->getSubExpr()))
5282 HandleLValueComplexElement(Info, E, Result, E->getType(), true);
5286 bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
5287 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5290 if (!this->Visit(UO->getSubExpr()))
5293 return handleIncDec(
5294 this->Info, UO, Result, UO->getSubExpr()->getType(),
5295 UO->isIncrementOp(), nullptr);
5298 bool LValueExprEvaluator::VisitCompoundAssignOperator(
5299 const CompoundAssignOperator *CAO) {
5300 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5305 // The overall lvalue result is the result of evaluating the LHS.
5306 if (!this->Visit(CAO->getLHS())) {
5307 if (Info.noteFailure())
5308 Evaluate(RHS, this->Info, CAO->getRHS());
5312 if (!Evaluate(RHS, this->Info, CAO->getRHS()))
5315 return handleCompoundAssignment(
5317 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
5318 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS);
5321 bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
5322 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5327 if (!this->Visit(E->getLHS())) {
5328 if (Info.noteFailure())
5329 Evaluate(NewVal, this->Info, E->getRHS());
5333 if (!Evaluate(NewVal, this->Info, E->getRHS()))
5336 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
5340 //===----------------------------------------------------------------------===//
5341 // Pointer Evaluation
5342 //===----------------------------------------------------------------------===//
5344 /// \brief Attempts to compute the number of bytes available at the pointer
5345 /// returned by a function with the alloc_size attribute. Returns true if we
5346 /// were successful. Places an unsigned number into `Result`.
5348 /// This expects the given CallExpr to be a call to a function with an
5349 /// alloc_size attribute.
5350 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
5351 const CallExpr *Call,
5352 llvm::APInt &Result) {
5353 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
5355 // alloc_size args are 1-indexed, 0 means not present.
5356 assert(AllocSize && AllocSize->getElemSizeParam() != 0);
5357 unsigned SizeArgNo = AllocSize->getElemSizeParam() - 1;
5358 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
5359 if (Call->getNumArgs() <= SizeArgNo)
5362 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
5363 if (!E->EvaluateAsInt(Into, Ctx, Expr::SE_AllowSideEffects))
5365 if (Into.isNegative() || !Into.isIntN(BitsInSizeT))
5367 Into = Into.zextOrSelf(BitsInSizeT);
5372 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
5375 if (!AllocSize->getNumElemsParam()) {
5376 Result = std::move(SizeOfElem);
5380 APSInt NumberOfElems;
5381 // Argument numbers start at 1
5382 unsigned NumArgNo = AllocSize->getNumElemsParam() - 1;
5383 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
5387 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow);
5391 Result = std::move(BytesAvailable);
5395 /// \brief Convenience function. LVal's base must be a call to an alloc_size
5397 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
5399 llvm::APInt &Result) {
5400 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
5401 "Can't get the size of a non alloc_size function");
5402 const auto *Base = LVal.getLValueBase().get<const Expr *>();
5403 const CallExpr *CE = tryUnwrapAllocSizeCall(Base);
5404 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result);
5407 /// \brief Attempts to evaluate the given LValueBase as the result of a call to
5408 /// a function with the alloc_size attribute. If it was possible to do so, this
5409 /// function will return true, make Result's Base point to said function call,
5410 /// and mark Result's Base as invalid.
5411 static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
5416 // Because we do no form of static analysis, we only support const variables.
5418 // Additionally, we can't support parameters, nor can we support static
5419 // variables (in the latter case, use-before-assign isn't UB; in the former,
5420 // we have no clue what they'll be assigned to).
5422 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>());
5423 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
5426 const Expr *Init = VD->getAnyInitializer();
5430 const Expr *E = Init->IgnoreParens();
5431 if (!tryUnwrapAllocSizeCall(E))
5434 // Store E instead of E unwrapped so that the type of the LValue's base is
5435 // what the user wanted.
5436 Result.setInvalid(E);
5438 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
5439 Result.addUnsizedArray(Info, Pointee);
5444 class PointerExprEvaluator
5445 : public ExprEvaluatorBase<PointerExprEvaluator> {
5449 bool Success(const Expr *E) {
5454 bool evaluateLValue(const Expr *E, LValue &Result) {
5455 return EvaluateLValue(E, Result, Info, InvalidBaseOK);
5458 bool evaluatePointer(const Expr *E, LValue &Result) {
5459 return EvaluatePointer(E, Result, Info, InvalidBaseOK);
5462 bool visitNonBuiltinCallExpr(const CallExpr *E);
5465 PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
5466 : ExprEvaluatorBaseTy(info), Result(Result),
5467 InvalidBaseOK(InvalidBaseOK) {}
5469 bool Success(const APValue &V, const Expr *E) {
5470 Result.setFrom(Info.Ctx, V);
5473 bool ZeroInitialization(const Expr *E) {
5474 auto Offset = Info.Ctx.getTargetNullPointerValue(E->getType());
5475 Result.set((Expr*)nullptr, 0, false, true, Offset);
5479 bool VisitBinaryOperator(const BinaryOperator *E);
5480 bool VisitCastExpr(const CastExpr* E);
5481 bool VisitUnaryAddrOf(const UnaryOperator *E);
5482 bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
5483 { return Success(E); }
5484 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
5485 if (Info.noteFailure())
5486 EvaluateIgnoredValue(Info, E->getSubExpr());
5489 bool VisitAddrLabelExpr(const AddrLabelExpr *E)
5490 { return Success(E); }
5491 bool VisitCallExpr(const CallExpr *E);
5492 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
5493 bool VisitBlockExpr(const BlockExpr *E) {
5494 if (!E->getBlockDecl()->hasCaptures())
5498 bool VisitCXXThisExpr(const CXXThisExpr *E) {
5499 // Can't look at 'this' when checking a potential constant expression.
5500 if (Info.checkingPotentialConstantExpression())
5502 if (!Info.CurrentCall->This) {
5503 if (Info.getLangOpts().CPlusPlus11)
5504 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
5509 Result = *Info.CurrentCall->This;
5510 // If we are inside a lambda's call operator, the 'this' expression refers
5511 // to the enclosing '*this' object (either by value or reference) which is
5512 // either copied into the closure object's field that represents the '*this'
5513 // or refers to '*this'.
5514 if (isLambdaCallOperator(Info.CurrentCall->Callee)) {
5515 // Update 'Result' to refer to the data member/field of the closure object
5516 // that represents the '*this' capture.
5517 if (!HandleLValueMember(Info, E, Result,
5518 Info.CurrentCall->LambdaThisCaptureField))
5520 // If we captured '*this' by reference, replace the field with its referent.
5521 if (Info.CurrentCall->LambdaThisCaptureField->getType()
5522 ->isPointerType()) {
5524 if (!handleLValueToRValueConversion(Info, E, E->getType(), Result,
5528 Result.setFrom(Info.Ctx, RVal);
5534 // FIXME: Missing: @protocol, @selector
5536 } // end anonymous namespace
5538 static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
5539 bool InvalidBaseOK) {
5540 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
5541 return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
5544 bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
5545 if (E->getOpcode() != BO_Add &&
5546 E->getOpcode() != BO_Sub)
5547 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
5549 const Expr *PExp = E->getLHS();
5550 const Expr *IExp = E->getRHS();
5551 if (IExp->getType()->isPointerType())
5552 std::swap(PExp, IExp);
5554 bool EvalPtrOK = evaluatePointer(PExp, Result);
5555 if (!EvalPtrOK && !Info.noteFailure())
5558 llvm::APSInt Offset;
5559 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
5562 if (E->getOpcode() == BO_Sub)
5563 negateAsSigned(Offset);
5565 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
5566 return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset);
5569 bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
5570 return evaluateLValue(E->getSubExpr(), Result);
5573 bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
5574 const Expr* SubExpr = E->getSubExpr();
5576 switch (E->getCastKind()) {
5581 case CK_CPointerToObjCPointerCast:
5582 case CK_BlockPointerToObjCPointerCast:
5583 case CK_AnyPointerToBlockPointerCast:
5584 case CK_AddressSpaceConversion:
5585 if (!Visit(SubExpr))
5587 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
5588 // permitted in constant expressions in C++11. Bitcasts from cv void* are
5589 // also static_casts, but we disallow them as a resolution to DR1312.
5590 if (!E->getType()->isVoidPointerType()) {
5591 Result.Designator.setInvalid();
5592 if (SubExpr->getType()->isVoidPointerType())
5593 CCEDiag(E, diag::note_constexpr_invalid_cast)
5594 << 3 << SubExpr->getType();
5596 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5598 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
5599 ZeroInitialization(E);
5602 case CK_DerivedToBase:
5603 case CK_UncheckedDerivedToBase:
5604 if (!evaluatePointer(E->getSubExpr(), Result))
5606 if (!Result.Base && Result.Offset.isZero())
5609 // Now figure out the necessary offset to add to the base LV to get from
5610 // the derived class to the base class.
5611 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()->
5612 castAs<PointerType>()->getPointeeType(),
5615 case CK_BaseToDerived:
5616 if (!Visit(E->getSubExpr()))
5618 if (!Result.Base && Result.Offset.isZero())
5620 return HandleBaseToDerivedCast(Info, E, Result);
5622 case CK_NullToPointer:
5623 VisitIgnoredValue(E->getSubExpr());
5624 return ZeroInitialization(E);
5626 case CK_IntegralToPointer: {
5627 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5630 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
5633 if (Value.isInt()) {
5634 unsigned Size = Info.Ctx.getTypeSize(E->getType());
5635 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
5636 Result.Base = (Expr*)nullptr;
5637 Result.InvalidBase = false;
5638 Result.Offset = CharUnits::fromQuantity(N);
5639 Result.CallIndex = 0;
5640 Result.Designator.setInvalid();
5641 Result.IsNullPtr = false;
5644 // Cast is of an lvalue, no need to change value.
5645 Result.setFrom(Info.Ctx, Value);
5649 case CK_ArrayToPointerDecay:
5650 if (SubExpr->isGLValue()) {
5651 if (!evaluateLValue(SubExpr, Result))
5654 Result.set(SubExpr, Info.CurrentCall->Index);
5655 if (!EvaluateInPlace(Info.CurrentCall->createTemporary(SubExpr, false),
5656 Info, Result, SubExpr))
5659 // The result is a pointer to the first element of the array.
5660 if (const ConstantArrayType *CAT
5661 = Info.Ctx.getAsConstantArrayType(SubExpr->getType()))
5662 Result.addArray(Info, E, CAT);
5664 Result.Designator.setInvalid();
5667 case CK_FunctionToPointerDecay:
5668 return evaluateLValue(SubExpr, Result);
5670 case CK_LValueToRValue: {
5672 if (!evaluateLValue(E->getSubExpr(), LVal))
5676 // Note, we use the subexpression's type in order to retain cv-qualifiers.
5677 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
5679 return InvalidBaseOK &&
5680 evaluateLValueAsAllocSize(Info, LVal.Base, Result);
5681 return Success(RVal, E);
5685 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5688 static CharUnits GetAlignOfType(EvalInfo &Info, QualType T) {
5689 // C++ [expr.alignof]p3:
5690 // When alignof is applied to a reference type, the result is the
5691 // alignment of the referenced type.
5692 if (const ReferenceType *Ref = T->getAs<ReferenceType>())
5693 T = Ref->getPointeeType();
5695 // __alignof is defined to return the preferred alignment.
5696 if (T.getQualifiers().hasUnaligned())
5697 return CharUnits::One();
5698 return Info.Ctx.toCharUnitsFromBits(
5699 Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
5702 static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E) {
5703 E = E->IgnoreParens();
5705 // The kinds of expressions that we have special-case logic here for
5706 // should be kept up to date with the special checks for those
5707 // expressions in Sema.
5709 // alignof decl is always accepted, even if it doesn't make sense: we default
5710 // to 1 in those cases.
5711 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
5712 return Info.Ctx.getDeclAlign(DRE->getDecl(),
5713 /*RefAsPointee*/true);
5715 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
5716 return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
5717 /*RefAsPointee*/true);
5719 return GetAlignOfType(Info, E->getType());
5722 // To be clear: this happily visits unsupported builtins. Better name welcomed.
5723 bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
5724 if (ExprEvaluatorBaseTy::VisitCallExpr(E))
5727 if (!(InvalidBaseOK && getAllocSizeAttr(E)))
5730 Result.setInvalid(E);
5731 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
5732 Result.addUnsizedArray(Info, PointeeTy);
5736 bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
5737 if (IsStringLiteralCall(E))
5740 if (unsigned BuiltinOp = E->getBuiltinCallee())
5741 return VisitBuiltinCallExpr(E, BuiltinOp);
5743 return visitNonBuiltinCallExpr(E);
5746 bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
5747 unsigned BuiltinOp) {
5748 switch (BuiltinOp) {
5749 case Builtin::BI__builtin_addressof:
5750 return evaluateLValue(E->getArg(0), Result);
5751 case Builtin::BI__builtin_assume_aligned: {
5752 // We need to be very careful here because: if the pointer does not have the
5753 // asserted alignment, then the behavior is undefined, and undefined
5754 // behavior is non-constant.
5755 if (!evaluatePointer(E->getArg(0), Result))
5758 LValue OffsetResult(Result);
5760 if (!EvaluateInteger(E->getArg(1), Alignment, Info))
5762 CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue());
5764 if (E->getNumArgs() > 2) {
5766 if (!EvaluateInteger(E->getArg(2), Offset, Info))
5769 int64_t AdditionalOffset = -Offset.getZExtValue();
5770 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
5773 // If there is a base object, then it must have the correct alignment.
5774 if (OffsetResult.Base) {
5775 CharUnits BaseAlignment;
5776 if (const ValueDecl *VD =
5777 OffsetResult.Base.dyn_cast<const ValueDecl*>()) {
5778 BaseAlignment = Info.Ctx.getDeclAlign(VD);
5781 GetAlignOfExpr(Info, OffsetResult.Base.get<const Expr*>());
5784 if (BaseAlignment < Align) {
5785 Result.Designator.setInvalid();
5786 // FIXME: Add support to Diagnostic for long / long long.
5787 CCEDiag(E->getArg(0),
5788 diag::note_constexpr_baa_insufficient_alignment) << 0
5789 << (unsigned)BaseAlignment.getQuantity()
5790 << (unsigned)Align.getQuantity();
5795 // The offset must also have the correct alignment.
5796 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
5797 Result.Designator.setInvalid();
5800 ? CCEDiag(E->getArg(0),
5801 diag::note_constexpr_baa_insufficient_alignment) << 1
5802 : CCEDiag(E->getArg(0),
5803 diag::note_constexpr_baa_value_insufficient_alignment))
5804 << (int)OffsetResult.Offset.getQuantity()
5805 << (unsigned)Align.getQuantity();
5812 case Builtin::BIstrchr:
5813 case Builtin::BIwcschr:
5814 case Builtin::BImemchr:
5815 case Builtin::BIwmemchr:
5816 if (Info.getLangOpts().CPlusPlus11)
5817 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
5818 << /*isConstexpr*/0 << /*isConstructor*/0
5819 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
5821 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
5823 case Builtin::BI__builtin_strchr:
5824 case Builtin::BI__builtin_wcschr:
5825 case Builtin::BI__builtin_memchr:
5826 case Builtin::BI__builtin_char_memchr:
5827 case Builtin::BI__builtin_wmemchr: {
5828 if (!Visit(E->getArg(0)))
5831 if (!EvaluateInteger(E->getArg(1), Desired, Info))
5833 uint64_t MaxLength = uint64_t(-1);
5834 if (BuiltinOp != Builtin::BIstrchr &&
5835 BuiltinOp != Builtin::BIwcschr &&
5836 BuiltinOp != Builtin::BI__builtin_strchr &&
5837 BuiltinOp != Builtin::BI__builtin_wcschr) {
5839 if (!EvaluateInteger(E->getArg(2), N, Info))
5841 MaxLength = N.getExtValue();
5844 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
5846 // Figure out what value we're actually looking for (after converting to
5847 // the corresponding unsigned type if necessary).
5848 uint64_t DesiredVal;
5849 bool StopAtNull = false;
5850 switch (BuiltinOp) {
5851 case Builtin::BIstrchr:
5852 case Builtin::BI__builtin_strchr:
5853 // strchr compares directly to the passed integer, and therefore
5854 // always fails if given an int that is not a char.
5855 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy,
5856 E->getArg(1)->getType(),
5859 return ZeroInitialization(E);
5862 case Builtin::BImemchr:
5863 case Builtin::BI__builtin_memchr:
5864 case Builtin::BI__builtin_char_memchr:
5865 // memchr compares by converting both sides to unsigned char. That's also
5866 // correct for strchr if we get this far (to cope with plain char being
5867 // unsigned in the strchr case).
5868 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue();
5871 case Builtin::BIwcschr:
5872 case Builtin::BI__builtin_wcschr:
5875 case Builtin::BIwmemchr:
5876 case Builtin::BI__builtin_wmemchr:
5877 // wcschr and wmemchr are given a wchar_t to look for. Just use it.
5878 DesiredVal = Desired.getZExtValue();
5882 for (; MaxLength; --MaxLength) {
5884 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
5887 if (Char.getInt().getZExtValue() == DesiredVal)
5889 if (StopAtNull && !Char.getInt())
5891 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
5894 // Not found: return nullptr.
5895 return ZeroInitialization(E);
5899 return visitNonBuiltinCallExpr(E);
5903 //===----------------------------------------------------------------------===//
5904 // Member Pointer Evaluation
5905 //===----------------------------------------------------------------------===//
5908 class MemberPointerExprEvaluator
5909 : public ExprEvaluatorBase<MemberPointerExprEvaluator> {
5912 bool Success(const ValueDecl *D) {
5913 Result = MemberPtr(D);
5918 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
5919 : ExprEvaluatorBaseTy(Info), Result(Result) {}
5921 bool Success(const APValue &V, const Expr *E) {
5925 bool ZeroInitialization(const Expr *E) {
5926 return Success((const ValueDecl*)nullptr);
5929 bool VisitCastExpr(const CastExpr *E);
5930 bool VisitUnaryAddrOf(const UnaryOperator *E);
5932 } // end anonymous namespace
5934 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
5936 assert(E->isRValue() && E->getType()->isMemberPointerType());
5937 return MemberPointerExprEvaluator(Info, Result).Visit(E);
5940 bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
5941 switch (E->getCastKind()) {
5943 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5945 case CK_NullToMemberPointer:
5946 VisitIgnoredValue(E->getSubExpr());
5947 return ZeroInitialization(E);
5949 case CK_BaseToDerivedMemberPointer: {
5950 if (!Visit(E->getSubExpr()))
5952 if (E->path_empty())
5954 // Base-to-derived member pointer casts store the path in derived-to-base
5955 // order, so iterate backwards. The CXXBaseSpecifier also provides us with
5956 // the wrong end of the derived->base arc, so stagger the path by one class.
5957 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
5958 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
5959 PathI != PathE; ++PathI) {
5960 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
5961 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
5962 if (!Result.castToDerived(Derived))
5965 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
5966 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
5971 case CK_DerivedToBaseMemberPointer:
5972 if (!Visit(E->getSubExpr()))
5974 for (CastExpr::path_const_iterator PathI = E->path_begin(),
5975 PathE = E->path_end(); PathI != PathE; ++PathI) {
5976 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
5977 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
5978 if (!Result.castToBase(Base))
5985 bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
5986 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
5987 // member can be formed.
5988 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
5991 //===----------------------------------------------------------------------===//
5992 // Record Evaluation
5993 //===----------------------------------------------------------------------===//
5996 class RecordExprEvaluator
5997 : public ExprEvaluatorBase<RecordExprEvaluator> {
6002 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
6003 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
6005 bool Success(const APValue &V, const Expr *E) {
6009 bool ZeroInitialization(const Expr *E) {
6010 return ZeroInitialization(E, E->getType());
6012 bool ZeroInitialization(const Expr *E, QualType T);
6014 bool VisitCallExpr(const CallExpr *E) {
6015 return handleCallExpr(E, Result, &This);
6017 bool VisitCastExpr(const CastExpr *E);
6018 bool VisitInitListExpr(const InitListExpr *E);
6019 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
6020 return VisitCXXConstructExpr(E, E->getType());
6022 bool VisitLambdaExpr(const LambdaExpr *E);
6023 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
6024 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
6025 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
6029 /// Perform zero-initialization on an object of non-union class type.
6030 /// C++11 [dcl.init]p5:
6031 /// To zero-initialize an object or reference of type T means:
6033 /// -- if T is a (possibly cv-qualified) non-union class type,
6034 /// each non-static data member and each base-class subobject is
6035 /// zero-initialized
6036 static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
6037 const RecordDecl *RD,
6038 const LValue &This, APValue &Result) {
6039 assert(!RD->isUnion() && "Expected non-union class type");
6040 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
6041 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
6042 std::distance(RD->field_begin(), RD->field_end()));
6044 if (RD->isInvalidDecl()) return false;
6045 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6049 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
6050 End = CD->bases_end(); I != End; ++I, ++Index) {
6051 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
6052 LValue Subobject = This;
6053 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout))
6055 if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
6056 Result.getStructBase(Index)))
6061 for (const auto *I : RD->fields()) {
6062 // -- if T is a reference type, no initialization is performed.
6063 if (I->getType()->isReferenceType())
6066 LValue Subobject = This;
6067 if (!HandleLValueMember(Info, E, Subobject, I, &Layout))
6070 ImplicitValueInitExpr VIE(I->getType());
6071 if (!EvaluateInPlace(
6072 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE))
6079 bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
6080 const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
6081 if (RD->isInvalidDecl()) return false;
6082 if (RD->isUnion()) {
6083 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
6084 // object's first non-static named data member is zero-initialized
6085 RecordDecl::field_iterator I = RD->field_begin();
6086 if (I == RD->field_end()) {
6087 Result = APValue((const FieldDecl*)nullptr);
6091 LValue Subobject = This;
6092 if (!HandleLValueMember(Info, E, Subobject, *I))
6094 Result = APValue(*I);
6095 ImplicitValueInitExpr VIE(I->getType());
6096 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
6099 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
6100 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
6104 return HandleClassZeroInitialization(Info, E, RD, This, Result);
6107 bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
6108 switch (E->getCastKind()) {
6110 return ExprEvaluatorBaseTy::VisitCastExpr(E);
6112 case CK_ConstructorConversion:
6113 return Visit(E->getSubExpr());
6115 case CK_DerivedToBase:
6116 case CK_UncheckedDerivedToBase: {
6117 APValue DerivedObject;
6118 if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
6120 if (!DerivedObject.isStruct())
6121 return Error(E->getSubExpr());
6123 // Derived-to-base rvalue conversion: just slice off the derived part.
6124 APValue *Value = &DerivedObject;
6125 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
6126 for (CastExpr::path_const_iterator PathI = E->path_begin(),
6127 PathE = E->path_end(); PathI != PathE; ++PathI) {
6128 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base");
6129 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
6130 Value = &Value->getStructBase(getBaseIndex(RD, Base));
6139 bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6140 if (E->isTransparent())
6141 return Visit(E->getInit(0));
6143 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
6144 if (RD->isInvalidDecl()) return false;
6145 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6147 if (RD->isUnion()) {
6148 const FieldDecl *Field = E->getInitializedFieldInUnion();
6149 Result = APValue(Field);
6153 // If the initializer list for a union does not contain any elements, the
6154 // first element of the union is value-initialized.
6155 // FIXME: The element should be initialized from an initializer list.
6156 // Is this difference ever observable for initializer lists which
6158 ImplicitValueInitExpr VIE(Field->getType());
6159 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;
6161 LValue Subobject = This;
6162 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout))
6165 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
6166 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
6167 isa<CXXDefaultInitExpr>(InitExpr));
6169 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr);
6172 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
6173 if (Result.isUninit())
6174 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
6175 std::distance(RD->field_begin(), RD->field_end()));
6176 unsigned ElementNo = 0;
6177 bool Success = true;
6179 // Initialize base classes.
6181 for (const auto &Base : CXXRD->bases()) {
6182 assert(ElementNo < E->getNumInits() && "missing init for base class");
6183 const Expr *Init = E->getInit(ElementNo);
6185 LValue Subobject = This;
6186 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base))
6189 APValue &FieldVal = Result.getStructBase(ElementNo);
6190 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) {
6191 if (!Info.noteFailure())
6199 // Initialize members.
6200 for (const auto *Field : RD->fields()) {
6201 // Anonymous bit-fields are not considered members of the class for
6202 // purposes of aggregate initialization.
6203 if (Field->isUnnamedBitfield())
6206 LValue Subobject = This;
6208 bool HaveInit = ElementNo < E->getNumInits();
6210 // FIXME: Diagnostics here should point to the end of the initializer
6211 // list, not the start.
6212 if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E,
6213 Subobject, Field, &Layout))
6216 // Perform an implicit value-initialization for members beyond the end of
6217 // the initializer list.
6218 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
6219 const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE;
6220 if (Init->isValueDependent()) {
6225 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
6226 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
6227 isa<CXXDefaultInitExpr>(Init));
6229 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
6230 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) ||
6231 (Field->isBitField() && !truncateBitfieldValue(Info, Init,
6232 FieldVal, Field))) {
6233 if (!Info.noteFailure())
6242 bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
6244 // Note that E's type is not necessarily the type of our class here; we might
6245 // be initializing an array element instead.
6246 const CXXConstructorDecl *FD = E->getConstructor();
6247 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
6249 bool ZeroInit = E->requiresZeroInitialization();
6250 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
6251 // If we've already performed zero-initialization, we're already done.
6252 if (!Result.isUninit())
6255 // We can get here in two different ways:
6256 // 1) We're performing value-initialization, and should zero-initialize
6258 // 2) We're performing default-initialization of an object with a trivial
6259 // constexpr default constructor, in which case we should start the
6260 // lifetimes of all the base subobjects (there can be no data member
6261 // subobjects in this case) per [basic.life]p1.
6262 // Either way, ZeroInitialization is appropriate.
6263 return ZeroInitialization(E, T);
6266 const FunctionDecl *Definition = nullptr;
6267 auto Body = FD->getBody(Definition);
6269 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
6272 // Avoid materializing a temporary for an elidable copy/move constructor.
6273 if (E->isElidable() && !ZeroInit)
6274 if (const MaterializeTemporaryExpr *ME
6275 = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0)))
6276 return Visit(ME->GetTemporaryExpr());
6278 if (ZeroInit && !ZeroInitialization(E, T))
6281 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
6282 return HandleConstructorCall(E, This, Args,
6283 cast<CXXConstructorDecl>(Definition), Info,
6287 bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
6288 const CXXInheritedCtorInitExpr *E) {
6289 if (!Info.CurrentCall) {
6290 assert(Info.checkingPotentialConstantExpression());
6294 const CXXConstructorDecl *FD = E->getConstructor();
6295 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
6298 const FunctionDecl *Definition = nullptr;
6299 auto Body = FD->getBody(Definition);
6301 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
6304 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
6305 cast<CXXConstructorDecl>(Definition), Info,
6309 bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
6310 const CXXStdInitializerListExpr *E) {
6311 const ConstantArrayType *ArrayType =
6312 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
6315 if (!EvaluateLValue(E->getSubExpr(), Array, Info))
6318 // Get a pointer to the first element of the array.
6319 Array.addArray(Info, E, ArrayType);
6321 // FIXME: Perform the checks on the field types in SemaInit.
6322 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
6323 RecordDecl::field_iterator Field = Record->field_begin();
6324 if (Field == Record->field_end())
6328 if (!Field->getType()->isPointerType() ||
6329 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
6330 ArrayType->getElementType()))
6333 // FIXME: What if the initializer_list type has base classes, etc?
6334 Result = APValue(APValue::UninitStruct(), 0, 2);
6335 Array.moveInto(Result.getStructField(0));
6337 if (++Field == Record->field_end())
6340 if (Field->getType()->isPointerType() &&
6341 Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
6342 ArrayType->getElementType())) {
6344 if (!HandleLValueArrayAdjustment(Info, E, Array,
6345 ArrayType->getElementType(),
6346 ArrayType->getSize().getZExtValue()))
6348 Array.moveInto(Result.getStructField(1));
6349 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
6351 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize()));
6355 if (++Field != Record->field_end())
6361 bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
6362 const CXXRecordDecl *ClosureClass = E->getLambdaClass();
6363 if (ClosureClass->isInvalidDecl()) return false;
6365 if (Info.checkingPotentialConstantExpression()) return true;
6367 const size_t NumFields =
6368 std::distance(ClosureClass->field_begin(), ClosureClass->field_end());
6370 assert(NumFields == (size_t)std::distance(E->capture_init_begin(),
6371 E->capture_init_end()) &&
6372 "The number of lambda capture initializers should equal the number of "
6373 "fields within the closure type");
6375 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields);
6376 // Iterate through all the lambda's closure object's fields and initialize
6378 auto *CaptureInitIt = E->capture_init_begin();
6379 const LambdaCapture *CaptureIt = ClosureClass->captures_begin();
6380 bool Success = true;
6381 for (const auto *Field : ClosureClass->fields()) {
6382 assert(CaptureInitIt != E->capture_init_end());
6383 // Get the initializer for this field
6384 Expr *const CurFieldInit = *CaptureInitIt++;
6386 // If there is no initializer, either this is a VLA or an error has
6391 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
6392 if (!EvaluateInPlace(FieldVal, Info, This, CurFieldInit)) {
6393 if (!Info.keepEvaluatingAfterFailure())
6402 static bool EvaluateRecord(const Expr *E, const LValue &This,
6403 APValue &Result, EvalInfo &Info) {
6404 assert(E->isRValue() && E->getType()->isRecordType() &&
6405 "can't evaluate expression as a record rvalue");
6406 return RecordExprEvaluator(Info, This, Result).Visit(E);
6409 //===----------------------------------------------------------------------===//
6410 // Temporary Evaluation
6412 // Temporaries are represented in the AST as rvalues, but generally behave like
6413 // lvalues. The full-object of which the temporary is a subobject is implicitly
6414 // materialized so that a reference can bind to it.
6415 //===----------------------------------------------------------------------===//
6417 class TemporaryExprEvaluator
6418 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
6420 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
6421 LValueExprEvaluatorBaseTy(Info, Result, false) {}
6423 /// Visit an expression which constructs the value of this temporary.
6424 bool VisitConstructExpr(const Expr *E) {
6425 Result.set(E, Info.CurrentCall->Index);
6426 return EvaluateInPlace(Info.CurrentCall->createTemporary(E, false),
6430 bool VisitCastExpr(const CastExpr *E) {
6431 switch (E->getCastKind()) {
6433 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
6435 case CK_ConstructorConversion:
6436 return VisitConstructExpr(E->getSubExpr());
6439 bool VisitInitListExpr(const InitListExpr *E) {
6440 return VisitConstructExpr(E);
6442 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
6443 return VisitConstructExpr(E);
6445 bool VisitCallExpr(const CallExpr *E) {
6446 return VisitConstructExpr(E);
6448 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
6449 return VisitConstructExpr(E);
6451 bool VisitLambdaExpr(const LambdaExpr *E) {
6452 return VisitConstructExpr(E);
6455 } // end anonymous namespace
6457 /// Evaluate an expression of record type as a temporary.
6458 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
6459 assert(E->isRValue() && E->getType()->isRecordType());
6460 return TemporaryExprEvaluator(Info, Result).Visit(E);
6463 //===----------------------------------------------------------------------===//
6464 // Vector Evaluation
6465 //===----------------------------------------------------------------------===//
6468 class VectorExprEvaluator
6469 : public ExprEvaluatorBase<VectorExprEvaluator> {
6473 VectorExprEvaluator(EvalInfo &info, APValue &Result)
6474 : ExprEvaluatorBaseTy(info), Result(Result) {}
6476 bool Success(ArrayRef<APValue> V, const Expr *E) {
6477 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements());
6478 // FIXME: remove this APValue copy.
6479 Result = APValue(V.data(), V.size());
6482 bool Success(const APValue &V, const Expr *E) {
6483 assert(V.isVector());
6487 bool ZeroInitialization(const Expr *E);
6489 bool VisitUnaryReal(const UnaryOperator *E)
6490 { return Visit(E->getSubExpr()); }
6491 bool VisitCastExpr(const CastExpr* E);
6492 bool VisitInitListExpr(const InitListExpr *E);
6493 bool VisitUnaryImag(const UnaryOperator *E);
6494 // FIXME: Missing: unary -, unary ~, binary add/sub/mul/div,
6495 // binary comparisons, binary and/or/xor,
6496 // shufflevector, ExtVectorElementExpr
6498 } // end anonymous namespace
6500 static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
6501 assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue");
6502 return VectorExprEvaluator(Info, Result).Visit(E);
6505 bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
6506 const VectorType *VTy = E->getType()->castAs<VectorType>();
6507 unsigned NElts = VTy->getNumElements();
6509 const Expr *SE = E->getSubExpr();
6510 QualType SETy = SE->getType();
6512 switch (E->getCastKind()) {
6513 case CK_VectorSplat: {
6514 APValue Val = APValue();
6515 if (SETy->isIntegerType()) {
6517 if (!EvaluateInteger(SE, IntResult, Info))
6519 Val = APValue(std::move(IntResult));
6520 } else if (SETy->isRealFloatingType()) {
6521 APFloat FloatResult(0.0);
6522 if (!EvaluateFloat(SE, FloatResult, Info))
6524 Val = APValue(std::move(FloatResult));
6529 // Splat and create vector APValue.
6530 SmallVector<APValue, 4> Elts(NElts, Val);
6531 return Success(Elts, E);
6534 // Evaluate the operand into an APInt we can extract from.
6535 llvm::APInt SValInt;
6536 if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
6538 // Extract the elements
6539 QualType EltTy = VTy->getElementType();
6540 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
6541 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
6542 SmallVector<APValue, 4> Elts;
6543 if (EltTy->isRealFloatingType()) {
6544 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
6545 unsigned FloatEltSize = EltSize;
6546 if (&Sem == &APFloat::x87DoubleExtended())
6548 for (unsigned i = 0; i < NElts; i++) {
6551 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
6553 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
6554 Elts.push_back(APValue(APFloat(Sem, Elt)));
6556 } else if (EltTy->isIntegerType()) {
6557 for (unsigned i = 0; i < NElts; i++) {
6560 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
6562 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
6563 Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType())));
6568 return Success(Elts, E);
6571 return ExprEvaluatorBaseTy::VisitCastExpr(E);
6576 VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6577 const VectorType *VT = E->getType()->castAs<VectorType>();
6578 unsigned NumInits = E->getNumInits();
6579 unsigned NumElements = VT->getNumElements();
6581 QualType EltTy = VT->getElementType();
6582 SmallVector<APValue, 4> Elements;
6584 // The number of initializers can be less than the number of
6585 // vector elements. For OpenCL, this can be due to nested vector
6586 // initialization. For GCC compatibility, missing trailing elements
6587 // should be initialized with zeroes.
6588 unsigned CountInits = 0, CountElts = 0;
6589 while (CountElts < NumElements) {
6590 // Handle nested vector initialization.
6591 if (CountInits < NumInits
6592 && E->getInit(CountInits)->getType()->isVectorType()) {
6594 if (!EvaluateVector(E->getInit(CountInits), v, Info))
6596 unsigned vlen = v.getVectorLength();
6597 for (unsigned j = 0; j < vlen; j++)
6598 Elements.push_back(v.getVectorElt(j));
6600 } else if (EltTy->isIntegerType()) {
6601 llvm::APSInt sInt(32);
6602 if (CountInits < NumInits) {
6603 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
6605 } else // trailing integer zero.
6606 sInt = Info.Ctx.MakeIntValue(0, EltTy);
6607 Elements.push_back(APValue(sInt));
6610 llvm::APFloat f(0.0);
6611 if (CountInits < NumInits) {
6612 if (!EvaluateFloat(E->getInit(CountInits), f, Info))
6614 } else // trailing float zero.
6615 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
6616 Elements.push_back(APValue(f));
6621 return Success(Elements, E);
6625 VectorExprEvaluator::ZeroInitialization(const Expr *E) {
6626 const VectorType *VT = E->getType()->getAs<VectorType>();
6627 QualType EltTy = VT->getElementType();
6628 APValue ZeroElement;
6629 if (EltTy->isIntegerType())
6630 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
6633 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
6635 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
6636 return Success(Elements, E);
6639 bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
6640 VisitIgnoredValue(E->getSubExpr());
6641 return ZeroInitialization(E);
6644 //===----------------------------------------------------------------------===//
6646 //===----------------------------------------------------------------------===//
6649 class ArrayExprEvaluator
6650 : public ExprEvaluatorBase<ArrayExprEvaluator> {
6655 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
6656 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
6658 bool Success(const APValue &V, const Expr *E) {
6659 assert((V.isArray() || V.isLValue()) &&
6660 "expected array or string literal");
6665 bool ZeroInitialization(const Expr *E) {
6666 const ConstantArrayType *CAT =
6667 Info.Ctx.getAsConstantArrayType(E->getType());
6671 Result = APValue(APValue::UninitArray(), 0,
6672 CAT->getSize().getZExtValue());
6673 if (!Result.hasArrayFiller()) return true;
6675 // Zero-initialize all elements.
6676 LValue Subobject = This;
6677 Subobject.addArray(Info, E, CAT);
6678 ImplicitValueInitExpr VIE(CAT->getElementType());
6679 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
6682 bool VisitCallExpr(const CallExpr *E) {
6683 return handleCallExpr(E, Result, &This);
6685 bool VisitInitListExpr(const InitListExpr *E);
6686 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
6687 bool VisitCXXConstructExpr(const CXXConstructExpr *E);
6688 bool VisitCXXConstructExpr(const CXXConstructExpr *E,
6689 const LValue &Subobject,
6690 APValue *Value, QualType Type);
6692 } // end anonymous namespace
6694 static bool EvaluateArray(const Expr *E, const LValue &This,
6695 APValue &Result, EvalInfo &Info) {
6696 assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue");
6697 return ArrayExprEvaluator(Info, This, Result).Visit(E);
6700 bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6701 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType());
6705 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
6706 // an appropriately-typed string literal enclosed in braces.
6707 if (E->isStringLiteralInit()) {
6709 if (!EvaluateLValue(E->getInit(0), LV, Info))
6713 return Success(Val, E);
6716 bool Success = true;
6718 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&
6719 "zero-initialized array shouldn't have any initialized elts");
6721 if (Result.isArray() && Result.hasArrayFiller())
6722 Filler = Result.getArrayFiller();
6724 unsigned NumEltsToInit = E->getNumInits();
6725 unsigned NumElts = CAT->getSize().getZExtValue();
6726 const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr;
6728 // If the initializer might depend on the array index, run it for each
6729 // array element. For now, just whitelist non-class value-initialization.
6730 if (NumEltsToInit != NumElts && !isa<ImplicitValueInitExpr>(FillerExpr))
6731 NumEltsToInit = NumElts;
6733 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
6735 // If the array was previously zero-initialized, preserve the
6736 // zero-initialized values.
6737 if (!Filler.isUninit()) {
6738 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
6739 Result.getArrayInitializedElt(I) = Filler;
6740 if (Result.hasArrayFiller())
6741 Result.getArrayFiller() = Filler;
6744 LValue Subobject = This;
6745 Subobject.addArray(Info, E, CAT);
6746 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
6748 Index < E->getNumInits() ? E->getInit(Index) : FillerExpr;
6749 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
6750 Info, Subobject, Init) ||
6751 !HandleLValueArrayAdjustment(Info, Init, Subobject,
6752 CAT->getElementType(), 1)) {
6753 if (!Info.noteFailure())
6759 if (!Result.hasArrayFiller())
6762 // If we get here, we have a trivial filler, which we can just evaluate
6763 // once and splat over the rest of the array elements.
6764 assert(FillerExpr && "no array filler for incomplete init list");
6765 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject,
6766 FillerExpr) && Success;
6769 bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
6770 if (E->getCommonExpr() &&
6771 !Evaluate(Info.CurrentCall->createTemporary(E->getCommonExpr(), false),
6772 Info, E->getCommonExpr()->getSourceExpr()))
6775 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());
6777 uint64_t Elements = CAT->getSize().getZExtValue();
6778 Result = APValue(APValue::UninitArray(), Elements, Elements);
6780 LValue Subobject = This;
6781 Subobject.addArray(Info, E, CAT);
6783 bool Success = true;
6784 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
6785 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
6786 Info, Subobject, E->getSubExpr()) ||
6787 !HandleLValueArrayAdjustment(Info, E, Subobject,
6788 CAT->getElementType(), 1)) {
6789 if (!Info.noteFailure())
6798 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
6799 return VisitCXXConstructExpr(E, This, &Result, E->getType());
6802 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
6803 const LValue &Subobject,
6806 bool HadZeroInit = !Value->isUninit();
6808 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
6809 unsigned N = CAT->getSize().getZExtValue();
6811 // Preserve the array filler if we had prior zero-initialization.
6813 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
6816 *Value = APValue(APValue::UninitArray(), N, N);
6819 for (unsigned I = 0; I != N; ++I)
6820 Value->getArrayInitializedElt(I) = Filler;
6822 // Initialize the elements.
6823 LValue ArrayElt = Subobject;
6824 ArrayElt.addArray(Info, E, CAT);
6825 for (unsigned I = 0; I != N; ++I)
6826 if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I),
6827 CAT->getElementType()) ||
6828 !HandleLValueArrayAdjustment(Info, E, ArrayElt,
6829 CAT->getElementType(), 1))
6835 if (!Type->isRecordType())
6838 return RecordExprEvaluator(Info, Subobject, *Value)
6839 .VisitCXXConstructExpr(E, Type);
6842 //===----------------------------------------------------------------------===//
6843 // Integer Evaluation
6845 // As a GNU extension, we support casting pointers to sufficiently-wide integer
6846 // types and back in constant folding. Integer values are thus represented
6847 // either as an integer-valued APValue, or as an lvalue-valued APValue.
6848 //===----------------------------------------------------------------------===//
6851 class IntExprEvaluator
6852 : public ExprEvaluatorBase<IntExprEvaluator> {
6855 IntExprEvaluator(EvalInfo &info, APValue &result)
6856 : ExprEvaluatorBaseTy(info), Result(result) {}
6858 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
6859 assert(E->getType()->isIntegralOrEnumerationType() &&
6860 "Invalid evaluation result.");
6861 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
6862 "Invalid evaluation result.");
6863 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
6864 "Invalid evaluation result.");
6865 Result = APValue(SI);
6868 bool Success(const llvm::APSInt &SI, const Expr *E) {
6869 return Success(SI, E, Result);
6872 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
6873 assert(E->getType()->isIntegralOrEnumerationType() &&
6874 "Invalid evaluation result.");
6875 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
6876 "Invalid evaluation result.");
6877 Result = APValue(APSInt(I));
6878 Result.getInt().setIsUnsigned(
6879 E->getType()->isUnsignedIntegerOrEnumerationType());
6882 bool Success(const llvm::APInt &I, const Expr *E) {
6883 return Success(I, E, Result);
6886 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
6887 assert(E->getType()->isIntegralOrEnumerationType() &&
6888 "Invalid evaluation result.");
6889 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
6892 bool Success(uint64_t Value, const Expr *E) {
6893 return Success(Value, E, Result);
6896 bool Success(CharUnits Size, const Expr *E) {
6897 return Success(Size.getQuantity(), E);
6900 bool Success(const APValue &V, const Expr *E) {
6901 if (V.isLValue() || V.isAddrLabelDiff()) {
6905 return Success(V.getInt(), E);
6908 bool ZeroInitialization(const Expr *E) { return Success(0, E); }
6910 //===--------------------------------------------------------------------===//
6912 //===--------------------------------------------------------------------===//
6914 bool VisitIntegerLiteral(const IntegerLiteral *E) {
6915 return Success(E->getValue(), E);
6917 bool VisitCharacterLiteral(const CharacterLiteral *E) {
6918 return Success(E->getValue(), E);
6921 bool CheckReferencedDecl(const Expr *E, const Decl *D);
6922 bool VisitDeclRefExpr(const DeclRefExpr *E) {
6923 if (CheckReferencedDecl(E, E->getDecl()))
6926 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
6928 bool VisitMemberExpr(const MemberExpr *E) {
6929 if (CheckReferencedDecl(E, E->getMemberDecl())) {
6930 VisitIgnoredBaseExpression(E->getBase());
6934 return ExprEvaluatorBaseTy::VisitMemberExpr(E);
6937 bool VisitCallExpr(const CallExpr *E);
6938 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
6939 bool VisitBinaryOperator(const BinaryOperator *E);
6940 bool VisitOffsetOfExpr(const OffsetOfExpr *E);
6941 bool VisitUnaryOperator(const UnaryOperator *E);
6943 bool VisitCastExpr(const CastExpr* E);
6944 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
6946 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
6947 return Success(E->getValue(), E);
6950 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
6951 return Success(E->getValue(), E);
6954 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
6955 if (Info.ArrayInitIndex == uint64_t(-1)) {
6956 // We were asked to evaluate this subexpression independent of the
6957 // enclosing ArrayInitLoopExpr. We can't do that.
6961 return Success(Info.ArrayInitIndex, E);
6964 // Note, GNU defines __null as an integer, not a pointer.
6965 bool VisitGNUNullExpr(const GNUNullExpr *E) {
6966 return ZeroInitialization(E);
6969 bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
6970 return Success(E->getValue(), E);
6973 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
6974 return Success(E->getValue(), E);
6977 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
6978 return Success(E->getValue(), E);
6981 bool VisitUnaryReal(const UnaryOperator *E);
6982 bool VisitUnaryImag(const UnaryOperator *E);
6984 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
6985 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
6987 // FIXME: Missing: array subscript of vector, member of vector
6989 } // end anonymous namespace
6991 /// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
6992 /// produce either the integer value or a pointer.
6994 /// GCC has a heinous extension which folds casts between pointer types and
6995 /// pointer-sized integral types. We support this by allowing the evaluation of
6996 /// an integer rvalue to produce a pointer (represented as an lvalue) instead.
6997 /// Some simple arithmetic on such values is supported (they are treated much
6999 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
7001 assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType());
7002 return IntExprEvaluator(Info, Result).Visit(E);
7005 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
7007 if (!EvaluateIntegerOrLValue(E, Val, Info))
7010 // FIXME: It would be better to produce the diagnostic for casting
7011 // a pointer to an integer.
7012 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
7015 Result = Val.getInt();
7019 /// Check whether the given declaration can be directly converted to an integral
7020 /// rvalue. If not, no diagnostic is produced; there are other things we can
7022 bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
7023 // Enums are integer constant exprs.
7024 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
7025 // Check for signedness/width mismatches between E type and ECD value.
7026 bool SameSign = (ECD->getInitVal().isSigned()
7027 == E->getType()->isSignedIntegerOrEnumerationType());
7028 bool SameWidth = (ECD->getInitVal().getBitWidth()
7029 == Info.Ctx.getIntWidth(E->getType()));
7030 if (SameSign && SameWidth)
7031 return Success(ECD->getInitVal(), E);
7033 // Get rid of mismatch (otherwise Success assertions will fail)
7034 // by computing a new value matching the type of E.
7035 llvm::APSInt Val = ECD->getInitVal();
7037 Val.setIsSigned(!ECD->getInitVal().isSigned());
7039 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
7040 return Success(Val, E);
7046 /// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
7048 static int EvaluateBuiltinClassifyType(const CallExpr *E,
7049 const LangOptions &LangOpts) {
7050 // The following enum mimics the values returned by GCC.
7051 // FIXME: Does GCC differ between lvalue and rvalue references here?
7052 enum gcc_type_class {
7054 void_type_class, integer_type_class, char_type_class,
7055 enumeral_type_class, boolean_type_class,
7056 pointer_type_class, reference_type_class, offset_type_class,
7057 real_type_class, complex_type_class,
7058 function_type_class, method_type_class,
7059 record_type_class, union_type_class,
7060 array_type_class, string_type_class,
7064 // If no argument was supplied, default to "no_type_class". This isn't
7065 // ideal, however it is what gcc does.
7066 if (E->getNumArgs() == 0)
7067 return no_type_class;
7069 QualType CanTy = E->getArg(0)->getType().getCanonicalType();
7070 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy);
7072 switch (CanTy->getTypeClass()) {
7073 #define TYPE(ID, BASE)
7074 #define DEPENDENT_TYPE(ID, BASE) case Type::ID:
7075 #define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
7076 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
7077 #include "clang/AST/TypeNodes.def"
7078 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7081 switch (BT->getKind()) {
7082 #define BUILTIN_TYPE(ID, SINGLETON_ID)
7083 #define SIGNED_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: return integer_type_class;
7084 #define FLOATING_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: return real_type_class;
7085 #define PLACEHOLDER_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: break;
7086 #include "clang/AST/BuiltinTypes.def"
7087 case BuiltinType::Void:
7088 return void_type_class;
7090 case BuiltinType::Bool:
7091 return boolean_type_class;
7093 case BuiltinType::Char_U: // gcc doesn't appear to use char_type_class
7094 case BuiltinType::UChar:
7095 case BuiltinType::UShort:
7096 case BuiltinType::UInt:
7097 case BuiltinType::ULong:
7098 case BuiltinType::ULongLong:
7099 case BuiltinType::UInt128:
7100 return integer_type_class;
7102 case BuiltinType::NullPtr:
7103 return pointer_type_class;
7105 case BuiltinType::WChar_U:
7106 case BuiltinType::Char16:
7107 case BuiltinType::Char32:
7108 case BuiltinType::ObjCId:
7109 case BuiltinType::ObjCClass:
7110 case BuiltinType::ObjCSel:
7111 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
7112 case BuiltinType::Id:
7113 #include "clang/Basic/OpenCLImageTypes.def"
7114 case BuiltinType::OCLSampler:
7115 case BuiltinType::OCLEvent:
7116 case BuiltinType::OCLClkEvent:
7117 case BuiltinType::OCLQueue:
7118 case BuiltinType::OCLReserveID:
7119 case BuiltinType::Dependent:
7120 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7124 return LangOpts.CPlusPlus ? enumeral_type_class : integer_type_class;
7128 return pointer_type_class;
7131 case Type::MemberPointer:
7132 if (CanTy->isMemberDataPointerType())
7133 return offset_type_class;
7135 // We expect member pointers to be either data or function pointers,
7137 assert(CanTy->isMemberFunctionPointerType());
7138 return method_type_class;
7142 return complex_type_class;
7144 case Type::FunctionNoProto:
7145 case Type::FunctionProto:
7146 return LangOpts.CPlusPlus ? function_type_class : pointer_type_class;
7149 if (const RecordType *RT = CanTy->getAs<RecordType>()) {
7150 switch (RT->getDecl()->getTagKind()) {
7151 case TagTypeKind::TTK_Struct:
7152 case TagTypeKind::TTK_Class:
7153 case TagTypeKind::TTK_Interface:
7154 return record_type_class;
7156 case TagTypeKind::TTK_Enum:
7157 return LangOpts.CPlusPlus ? enumeral_type_class : integer_type_class;
7159 case TagTypeKind::TTK_Union:
7160 return union_type_class;
7163 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7165 case Type::ConstantArray:
7166 case Type::VariableArray:
7167 case Type::IncompleteArray:
7168 return LangOpts.CPlusPlus ? array_type_class : pointer_type_class;
7170 case Type::BlockPointer:
7171 case Type::LValueReference:
7172 case Type::RValueReference:
7174 case Type::ExtVector:
7176 case Type::DeducedTemplateSpecialization:
7177 case Type::ObjCObject:
7178 case Type::ObjCInterface:
7179 case Type::ObjCObjectPointer:
7182 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7185 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7188 /// EvaluateBuiltinConstantPForLValue - Determine the result of
7189 /// __builtin_constant_p when applied to the given lvalue.
7191 /// An lvalue is only "constant" if it is a pointer or reference to the first
7192 /// character of a string literal.
7193 template<typename LValue>
7194 static bool EvaluateBuiltinConstantPForLValue(const LValue &LV) {
7195 const Expr *E = LV.getLValueBase().template dyn_cast<const Expr*>();
7196 return E && isa<StringLiteral>(E) && LV.getLValueOffset().isZero();
7199 /// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
7200 /// GCC as we can manage.
7201 static bool EvaluateBuiltinConstantP(ASTContext &Ctx, const Expr *Arg) {
7202 QualType ArgType = Arg->getType();
7204 // __builtin_constant_p always has one operand. The rules which gcc follows
7205 // are not precisely documented, but are as follows:
7207 // - If the operand is of integral, floating, complex or enumeration type,
7208 // and can be folded to a known value of that type, it returns 1.
7209 // - If the operand and can be folded to a pointer to the first character
7210 // of a string literal (or such a pointer cast to an integral type), it
7213 // Otherwise, it returns 0.
7215 // FIXME: GCC also intends to return 1 for literals of aggregate types, but
7216 // its support for this does not currently work.
7217 if (ArgType->isIntegralOrEnumerationType()) {
7218 Expr::EvalResult Result;
7219 if (!Arg->EvaluateAsRValue(Result, Ctx) || Result.HasSideEffects)
7222 APValue &V = Result.Val;
7223 if (V.getKind() == APValue::Int)
7225 if (V.getKind() == APValue::LValue)
7226 return EvaluateBuiltinConstantPForLValue(V);
7227 } else if (ArgType->isFloatingType() || ArgType->isAnyComplexType()) {
7228 return Arg->isEvaluatable(Ctx);
7229 } else if (ArgType->isPointerType() || Arg->isGLValue()) {
7231 Expr::EvalStatus Status;
7232 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
7233 if ((Arg->isGLValue() ? EvaluateLValue(Arg, LV, Info)
7234 : EvaluatePointer(Arg, LV, Info)) &&
7235 !Status.HasSideEffects)
7236 return EvaluateBuiltinConstantPForLValue(LV);
7239 // Anything else isn't considered to be sufficiently constant.
7243 /// Retrieves the "underlying object type" of the given expression,
7244 /// as used by __builtin_object_size.
7245 static QualType getObjectType(APValue::LValueBase B) {
7246 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
7247 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
7248 return VD->getType();
7249 } else if (const Expr *E = B.get<const Expr*>()) {
7250 if (isa<CompoundLiteralExpr>(E))
7251 return E->getType();
7257 /// A more selective version of E->IgnoreParenCasts for
7258 /// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
7259 /// to change the type of E.
7260 /// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
7262 /// Always returns an RValue with a pointer representation.
7263 static const Expr *ignorePointerCastsAndParens(const Expr *E) {
7264 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
7266 auto *NoParens = E->IgnoreParens();
7267 auto *Cast = dyn_cast<CastExpr>(NoParens);
7268 if (Cast == nullptr)
7271 // We only conservatively allow a few kinds of casts, because this code is
7272 // inherently a simple solution that seeks to support the common case.
7273 auto CastKind = Cast->getCastKind();
7274 if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
7275 CastKind != CK_AddressSpaceConversion)
7278 auto *SubExpr = Cast->getSubExpr();
7279 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isRValue())
7281 return ignorePointerCastsAndParens(SubExpr);
7284 /// Checks to see if the given LValue's Designator is at the end of the LValue's
7285 /// record layout. e.g.
7286 /// struct { struct { int a, b; } fst, snd; } obj;
7292 /// obj.snd.b // yes
7294 /// Please note: this function is specialized for how __builtin_object_size
7295 /// views "objects".
7297 /// If this encounters an invalid RecordDecl, it will always return true.
7298 static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
7299 assert(!LVal.Designator.Invalid);
7301 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
7302 const RecordDecl *Parent = FD->getParent();
7303 Invalid = Parent->isInvalidDecl();
7304 if (Invalid || Parent->isUnion())
7306 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent);
7307 return FD->getFieldIndex() + 1 == Layout.getFieldCount();
7310 auto &Base = LVal.getLValueBase();
7311 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) {
7312 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
7314 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
7316 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) {
7317 for (auto *FD : IFD->chain()) {
7319 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid))
7326 QualType BaseType = getType(Base);
7327 if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
7328 assert(isBaseAnAllocSizeCall(Base) &&
7329 "Unsized array in non-alloc_size call?");
7330 // If this is an alloc_size base, we should ignore the initial array index
7332 BaseType = BaseType->castAs<PointerType>()->getPointeeType();
7335 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
7336 const auto &Entry = LVal.Designator.Entries[I];
7337 if (BaseType->isArrayType()) {
7338 // Because __builtin_object_size treats arrays as objects, we can ignore
7339 // the index iff this is the last array in the Designator.
7342 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType));
7343 uint64_t Index = Entry.ArrayIndex;
7344 if (Index + 1 != CAT->getSize())
7346 BaseType = CAT->getElementType();
7347 } else if (BaseType->isAnyComplexType()) {
7348 const auto *CT = BaseType->castAs<ComplexType>();
7349 uint64_t Index = Entry.ArrayIndex;
7352 BaseType = CT->getElementType();
7353 } else if (auto *FD = getAsField(Entry)) {
7355 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
7357 BaseType = FD->getType();
7359 assert(getAsBaseClass(Entry) && "Expecting cast to a base class");
7366 /// Tests to see if the LValue has a user-specified designator (that isn't
7367 /// necessarily valid). Note that this always returns 'true' if the LValue has
7368 /// an unsized array as its first designator entry, because there's currently no
7369 /// way to tell if the user typed *foo or foo[0].
7370 static bool refersToCompleteObject(const LValue &LVal) {
7371 if (LVal.Designator.Invalid)
7374 if (!LVal.Designator.Entries.empty())
7375 return LVal.Designator.isMostDerivedAnUnsizedArray();
7377 if (!LVal.InvalidBase)
7380 // If `E` is a MemberExpr, then the first part of the designator is hiding in
7382 const auto *E = LVal.Base.dyn_cast<const Expr *>();
7383 return !E || !isa<MemberExpr>(E);
7386 /// Attempts to detect a user writing into a piece of memory that's impossible
7387 /// to figure out the size of by just using types.
7388 static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
7389 const SubobjectDesignator &Designator = LVal.Designator;
7391 // - Users can only write off of the end when we have an invalid base. Invalid
7392 // bases imply we don't know where the memory came from.
7393 // - We used to be a bit more aggressive here; we'd only be conservative if
7394 // the array at the end was flexible, or if it had 0 or 1 elements. This
7395 // broke some common standard library extensions (PR30346), but was
7396 // otherwise seemingly fine. It may be useful to reintroduce this behavior
7397 // with some sort of whitelist. OTOH, it seems that GCC is always
7398 // conservative with the last element in structs (if it's an array), so our
7399 // current behavior is more compatible than a whitelisting approach would
7401 return LVal.InvalidBase &&
7402 Designator.Entries.size() == Designator.MostDerivedPathLength &&
7403 Designator.MostDerivedIsArrayElement &&
7404 isDesignatorAtObjectEnd(Ctx, LVal);
7407 /// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
7408 /// Fails if the conversion would cause loss of precision.
7409 static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
7410 CharUnits &Result) {
7411 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
7412 if (Int.ugt(CharUnitsMax))
7414 Result = CharUnits::fromQuantity(Int.getZExtValue());
7418 /// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
7419 /// determine how many bytes exist from the beginning of the object to either
7420 /// the end of the current subobject, or the end of the object itself, depending
7421 /// on what the LValue looks like + the value of Type.
7423 /// If this returns false, the value of Result is undefined.
7424 static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
7425 unsigned Type, const LValue &LVal,
7426 CharUnits &EndOffset) {
7427 bool DetermineForCompleteObject = refersToCompleteObject(LVal);
7429 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
7430 if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
7432 return HandleSizeof(Info, ExprLoc, Ty, Result);
7435 // We want to evaluate the size of the entire object. This is a valid fallback
7436 // for when Type=1 and the designator is invalid, because we're asked for an
7438 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
7439 // Type=3 wants a lower bound, so we can't fall back to this.
7440 if (Type == 3 && !DetermineForCompleteObject)
7443 llvm::APInt APEndOffset;
7444 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
7445 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
7446 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
7448 if (LVal.InvalidBase)
7451 QualType BaseTy = getObjectType(LVal.getLValueBase());
7452 return CheckedHandleSizeof(BaseTy, EndOffset);
7455 // We want to evaluate the size of a subobject.
7456 const SubobjectDesignator &Designator = LVal.Designator;
7458 // The following is a moderately common idiom in C:
7460 // struct Foo { int a; char c[1]; };
7461 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
7462 // strcpy(&F->c[0], Bar);
7464 // In order to not break too much legacy code, we need to support it.
7465 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) {
7466 // If we can resolve this to an alloc_size call, we can hand that back,
7467 // because we know for certain how many bytes there are to write to.
7468 llvm::APInt APEndOffset;
7469 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
7470 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
7471 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
7473 // If we cannot determine the size of the initial allocation, then we can't
7474 // given an accurate upper-bound. However, we are still able to give
7475 // conservative lower-bounds for Type=3.
7480 CharUnits BytesPerElem;
7481 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
7484 // According to the GCC documentation, we want the size of the subobject
7485 // denoted by the pointer. But that's not quite right -- what we actually
7486 // want is the size of the immediately-enclosing array, if there is one.
7487 int64_t ElemsRemaining;
7488 if (Designator.MostDerivedIsArrayElement &&
7489 Designator.Entries.size() == Designator.MostDerivedPathLength) {
7490 uint64_t ArraySize = Designator.getMostDerivedArraySize();
7491 uint64_t ArrayIndex = Designator.Entries.back().ArrayIndex;
7492 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
7494 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
7497 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
7501 /// \brief Tries to evaluate the __builtin_object_size for @p E. If successful,
7502 /// returns true and stores the result in @p Size.
7504 /// If @p WasError is non-null, this will report whether the failure to evaluate
7505 /// is to be treated as an Error in IntExprEvaluator.
7506 static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
7507 EvalInfo &Info, uint64_t &Size) {
7508 // Determine the denoted object.
7511 // The operand of __builtin_object_size is never evaluated for side-effects.
7512 // If there are any, but we can determine the pointed-to object anyway, then
7513 // ignore the side-effects.
7514 SpeculativeEvaluationRAII SpeculativeEval(Info);
7515 FoldOffsetRAII Fold(Info);
7517 if (E->isGLValue()) {
7518 // It's possible for us to be given GLValues if we're called via
7519 // Expr::tryEvaluateObjectSize.
7521 if (!EvaluateAsRValue(Info, E, RVal))
7523 LVal.setFrom(Info.Ctx, RVal);
7524 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info,
7525 /*InvalidBaseOK=*/true))
7529 // If we point to before the start of the object, there are no accessible
7531 if (LVal.getLValueOffset().isNegative()) {
7536 CharUnits EndOffset;
7537 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset))
7540 // If we've fallen outside of the end offset, just pretend there's nothing to
7541 // write to/read from.
7542 if (EndOffset <= LVal.getLValueOffset())
7545 Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
7549 bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
7550 if (unsigned BuiltinOp = E->getBuiltinCallee())
7551 return VisitBuiltinCallExpr(E, BuiltinOp);
7553 return ExprEvaluatorBaseTy::VisitCallExpr(E);
7556 bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
7557 unsigned BuiltinOp) {
7558 switch (unsigned BuiltinOp = E->getBuiltinCallee()) {
7560 return ExprEvaluatorBaseTy::VisitCallExpr(E);
7562 case Builtin::BI__builtin_object_size: {
7563 // The type was checked when we built the expression.
7565 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
7566 assert(Type <= 3 && "unexpected type");
7569 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size))
7570 return Success(Size, E);
7572 if (E->getArg(0)->HasSideEffects(Info.Ctx))
7573 return Success((Type & 2) ? 0 : -1, E);
7575 // Expression had no side effects, but we couldn't statically determine the
7576 // size of the referenced object.
7577 switch (Info.EvalMode) {
7578 case EvalInfo::EM_ConstantExpression:
7579 case EvalInfo::EM_PotentialConstantExpression:
7580 case EvalInfo::EM_ConstantFold:
7581 case EvalInfo::EM_EvaluateForOverflow:
7582 case EvalInfo::EM_IgnoreSideEffects:
7583 case EvalInfo::EM_OffsetFold:
7584 // Leave it to IR generation.
7586 case EvalInfo::EM_ConstantExpressionUnevaluated:
7587 case EvalInfo::EM_PotentialConstantExpressionUnevaluated:
7588 // Reduce it to a constant now.
7589 return Success((Type & 2) ? 0 : -1, E);
7592 llvm_unreachable("unexpected EvalMode");
7595 case Builtin::BI__builtin_bswap16:
7596 case Builtin::BI__builtin_bswap32:
7597 case Builtin::BI__builtin_bswap64: {
7599 if (!EvaluateInteger(E->getArg(0), Val, Info))
7602 return Success(Val.byteSwap(), E);
7605 case Builtin::BI__builtin_classify_type:
7606 return Success(EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E);
7608 // FIXME: BI__builtin_clrsb
7609 // FIXME: BI__builtin_clrsbl
7610 // FIXME: BI__builtin_clrsbll
7612 case Builtin::BI__builtin_clz:
7613 case Builtin::BI__builtin_clzl:
7614 case Builtin::BI__builtin_clzll:
7615 case Builtin::BI__builtin_clzs: {
7617 if (!EvaluateInteger(E->getArg(0), Val, Info))
7622 return Success(Val.countLeadingZeros(), E);
7625 case Builtin::BI__builtin_constant_p:
7626 return Success(EvaluateBuiltinConstantP(Info.Ctx, E->getArg(0)), E);
7628 case Builtin::BI__builtin_ctz:
7629 case Builtin::BI__builtin_ctzl:
7630 case Builtin::BI__builtin_ctzll:
7631 case Builtin::BI__builtin_ctzs: {
7633 if (!EvaluateInteger(E->getArg(0), Val, Info))
7638 return Success(Val.countTrailingZeros(), E);
7641 case Builtin::BI__builtin_eh_return_data_regno: {
7642 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
7643 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
7644 return Success(Operand, E);
7647 case Builtin::BI__builtin_expect:
7648 return Visit(E->getArg(0));
7650 case Builtin::BI__builtin_ffs:
7651 case Builtin::BI__builtin_ffsl:
7652 case Builtin::BI__builtin_ffsll: {
7654 if (!EvaluateInteger(E->getArg(0), Val, Info))
7657 unsigned N = Val.countTrailingZeros();
7658 return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
7661 case Builtin::BI__builtin_fpclassify: {
7663 if (!EvaluateFloat(E->getArg(5), Val, Info))
7666 switch (Val.getCategory()) {
7667 case APFloat::fcNaN: Arg = 0; break;
7668 case APFloat::fcInfinity: Arg = 1; break;
7669 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
7670 case APFloat::fcZero: Arg = 4; break;
7672 return Visit(E->getArg(Arg));
7675 case Builtin::BI__builtin_isinf_sign: {
7677 return EvaluateFloat(E->getArg(0), Val, Info) &&
7678 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
7681 case Builtin::BI__builtin_isinf: {
7683 return EvaluateFloat(E->getArg(0), Val, Info) &&
7684 Success(Val.isInfinity() ? 1 : 0, E);
7687 case Builtin::BI__builtin_isfinite: {
7689 return EvaluateFloat(E->getArg(0), Val, Info) &&
7690 Success(Val.isFinite() ? 1 : 0, E);
7693 case Builtin::BI__builtin_isnan: {
7695 return EvaluateFloat(E->getArg(0), Val, Info) &&
7696 Success(Val.isNaN() ? 1 : 0, E);
7699 case Builtin::BI__builtin_isnormal: {
7701 return EvaluateFloat(E->getArg(0), Val, Info) &&
7702 Success(Val.isNormal() ? 1 : 0, E);
7705 case Builtin::BI__builtin_parity:
7706 case Builtin::BI__builtin_parityl:
7707 case Builtin::BI__builtin_parityll: {
7709 if (!EvaluateInteger(E->getArg(0), Val, Info))
7712 return Success(Val.countPopulation() % 2, E);
7715 case Builtin::BI__builtin_popcount:
7716 case Builtin::BI__builtin_popcountl:
7717 case Builtin::BI__builtin_popcountll: {
7719 if (!EvaluateInteger(E->getArg(0), Val, Info))
7722 return Success(Val.countPopulation(), E);
7725 case Builtin::BIstrlen:
7726 case Builtin::BIwcslen:
7727 // A call to strlen is not a constant expression.
7728 if (Info.getLangOpts().CPlusPlus11)
7729 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
7730 << /*isConstexpr*/0 << /*isConstructor*/0
7731 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
7733 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
7735 case Builtin::BI__builtin_strlen:
7736 case Builtin::BI__builtin_wcslen: {
7737 // As an extension, we support __builtin_strlen() as a constant expression,
7738 // and support folding strlen() to a constant.
7740 if (!EvaluatePointer(E->getArg(0), String, Info))
7743 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
7745 // Fast path: if it's a string literal, search the string value.
7746 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
7747 String.getLValueBase().dyn_cast<const Expr *>())) {
7748 // The string literal may have embedded null characters. Find the first
7749 // one and truncate there.
7750 StringRef Str = S->getBytes();
7751 int64_t Off = String.Offset.getQuantity();
7752 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
7753 S->getCharByteWidth() == 1 &&
7754 // FIXME: Add fast-path for wchar_t too.
7755 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) {
7756 Str = Str.substr(Off);
7758 StringRef::size_type Pos = Str.find(0);
7759 if (Pos != StringRef::npos)
7760 Str = Str.substr(0, Pos);
7762 return Success(Str.size(), E);
7765 // Fall through to slow path to issue appropriate diagnostic.
7768 // Slow path: scan the bytes of the string looking for the terminating 0.
7769 for (uint64_t Strlen = 0; /**/; ++Strlen) {
7771 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) ||
7775 return Success(Strlen, E);
7776 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1))
7781 case Builtin::BIstrcmp:
7782 case Builtin::BIwcscmp:
7783 case Builtin::BIstrncmp:
7784 case Builtin::BIwcsncmp:
7785 case Builtin::BImemcmp:
7786 case Builtin::BIwmemcmp:
7787 // A call to strlen is not a constant expression.
7788 if (Info.getLangOpts().CPlusPlus11)
7789 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
7790 << /*isConstexpr*/0 << /*isConstructor*/0
7791 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
7793 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
7795 case Builtin::BI__builtin_strcmp:
7796 case Builtin::BI__builtin_wcscmp:
7797 case Builtin::BI__builtin_strncmp:
7798 case Builtin::BI__builtin_wcsncmp:
7799 case Builtin::BI__builtin_memcmp:
7800 case Builtin::BI__builtin_wmemcmp: {
7801 LValue String1, String2;
7802 if (!EvaluatePointer(E->getArg(0), String1, Info) ||
7803 !EvaluatePointer(E->getArg(1), String2, Info))
7806 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
7808 uint64_t MaxLength = uint64_t(-1);
7809 if (BuiltinOp != Builtin::BIstrcmp &&
7810 BuiltinOp != Builtin::BIwcscmp &&
7811 BuiltinOp != Builtin::BI__builtin_strcmp &&
7812 BuiltinOp != Builtin::BI__builtin_wcscmp) {
7814 if (!EvaluateInteger(E->getArg(2), N, Info))
7816 MaxLength = N.getExtValue();
7818 bool StopAtNull = (BuiltinOp != Builtin::BImemcmp &&
7819 BuiltinOp != Builtin::BIwmemcmp &&
7820 BuiltinOp != Builtin::BI__builtin_memcmp &&
7821 BuiltinOp != Builtin::BI__builtin_wmemcmp);
7822 for (; MaxLength; --MaxLength) {
7823 APValue Char1, Char2;
7824 if (!handleLValueToRValueConversion(Info, E, CharTy, String1, Char1) ||
7825 !handleLValueToRValueConversion(Info, E, CharTy, String2, Char2) ||
7826 !Char1.isInt() || !Char2.isInt())
7828 if (Char1.getInt() != Char2.getInt())
7829 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
7830 if (StopAtNull && !Char1.getInt())
7831 return Success(0, E);
7832 assert(!(StopAtNull && !Char2.getInt()));
7833 if (!HandleLValueArrayAdjustment(Info, E, String1, CharTy, 1) ||
7834 !HandleLValueArrayAdjustment(Info, E, String2, CharTy, 1))
7837 // We hit the strncmp / memcmp limit.
7838 return Success(0, E);
7841 case Builtin::BI__atomic_always_lock_free:
7842 case Builtin::BI__atomic_is_lock_free:
7843 case Builtin::BI__c11_atomic_is_lock_free: {
7845 if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
7848 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
7849 // of two less than the maximum inline atomic width, we know it is
7850 // lock-free. If the size isn't a power of two, or greater than the
7851 // maximum alignment where we promote atomics, we know it is not lock-free
7852 // (at least not in the sense of atomic_is_lock_free). Otherwise,
7853 // the answer can only be determined at runtime; for example, 16-byte
7854 // atomics have lock-free implementations on some, but not all,
7855 // x86-64 processors.
7857 // Check power-of-two.
7858 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
7859 if (Size.isPowerOfTwo()) {
7860 // Check against inlining width.
7861 unsigned InlineWidthBits =
7862 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
7863 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
7864 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
7865 Size == CharUnits::One() ||
7866 E->getArg(1)->isNullPointerConstant(Info.Ctx,
7867 Expr::NPC_NeverValueDependent))
7868 // OK, we will inline appropriately-aligned operations of this size,
7869 // and _Atomic(T) is appropriately-aligned.
7870 return Success(1, E);
7872 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
7873 castAs<PointerType>()->getPointeeType();
7874 if (!PointeeType->isIncompleteType() &&
7875 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
7876 // OK, we will inline operations on this object.
7877 return Success(1, E);
7882 return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
7883 Success(0, E) : Error(E);
7888 static bool HasSameBase(const LValue &A, const LValue &B) {
7889 if (!A.getLValueBase())
7890 return !B.getLValueBase();
7891 if (!B.getLValueBase())
7894 if (A.getLValueBase().getOpaqueValue() !=
7895 B.getLValueBase().getOpaqueValue()) {
7896 const Decl *ADecl = GetLValueBaseDecl(A);
7899 const Decl *BDecl = GetLValueBaseDecl(B);
7900 if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl())
7904 return IsGlobalLValue(A.getLValueBase()) ||
7905 A.getLValueCallIndex() == B.getLValueCallIndex();
7908 /// \brief Determine whether this is a pointer past the end of the complete
7909 /// object referred to by the lvalue.
7910 static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
7912 // A null pointer can be viewed as being "past the end" but we don't
7913 // choose to look at it that way here.
7914 if (!LV.getLValueBase())
7917 // If the designator is valid and refers to a subobject, we're not pointing
7919 if (!LV.getLValueDesignator().Invalid &&
7920 !LV.getLValueDesignator().isOnePastTheEnd())
7923 // A pointer to an incomplete type might be past-the-end if the type's size is
7924 // zero. We cannot tell because the type is incomplete.
7925 QualType Ty = getType(LV.getLValueBase());
7926 if (Ty->isIncompleteType())
7929 // We're a past-the-end pointer if we point to the byte after the object,
7930 // no matter what our type or path is.
7931 auto Size = Ctx.getTypeSizeInChars(Ty);
7932 return LV.getLValueOffset() == Size;
7937 /// \brief Data recursive integer evaluator of certain binary operators.
7939 /// We use a data recursive algorithm for binary operators so that we are able
7940 /// to handle extreme cases of chained binary operators without causing stack
7942 class DataRecursiveIntBinOpEvaluator {
7947 EvalResult() : Failed(false) { }
7949 void swap(EvalResult &RHS) {
7951 Failed = RHS.Failed;
7958 EvalResult LHSResult; // meaningful only for binary operator expression.
7959 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
7962 Job(Job &&) = default;
7964 void startSpeculativeEval(EvalInfo &Info) {
7965 SpecEvalRAII = SpeculativeEvaluationRAII(Info);
7969 SpeculativeEvaluationRAII SpecEvalRAII;
7972 SmallVector<Job, 16> Queue;
7974 IntExprEvaluator &IntEval;
7976 APValue &FinalResult;
7979 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
7980 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
7982 /// \brief True if \param E is a binary operator that we are going to handle
7983 /// data recursively.
7984 /// We handle binary operators that are comma, logical, or that have operands
7985 /// with integral or enumeration type.
7986 static bool shouldEnqueue(const BinaryOperator *E) {
7987 return E->getOpcode() == BO_Comma ||
7990 E->getType()->isIntegralOrEnumerationType() &&
7991 E->getLHS()->getType()->isIntegralOrEnumerationType() &&
7992 E->getRHS()->getType()->isIntegralOrEnumerationType());
7995 bool Traverse(const BinaryOperator *E) {
7997 EvalResult PrevResult;
7998 while (!Queue.empty())
7999 process(PrevResult);
8001 if (PrevResult.Failed) return false;
8003 FinalResult.swap(PrevResult.Val);
8008 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
8009 return IntEval.Success(Value, E, Result);
8011 bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
8012 return IntEval.Success(Value, E, Result);
8014 bool Error(const Expr *E) {
8015 return IntEval.Error(E);
8017 bool Error(const Expr *E, diag::kind D) {
8018 return IntEval.Error(E, D);
8021 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
8022 return Info.CCEDiag(E, D);
8025 // \brief Returns true if visiting the RHS is necessary, false otherwise.
8026 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
8027 bool &SuppressRHSDiags);
8029 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
8030 const BinaryOperator *E, APValue &Result);
8032 void EvaluateExpr(const Expr *E, EvalResult &Result) {
8033 Result.Failed = !Evaluate(Result.Val, Info, E);
8035 Result.Val = APValue();
8038 void process(EvalResult &Result);
8040 void enqueue(const Expr *E) {
8041 E = E->IgnoreParens();
8042 Queue.resize(Queue.size()+1);
8044 Queue.back().Kind = Job::AnyExprKind;
8050 bool DataRecursiveIntBinOpEvaluator::
8051 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
8052 bool &SuppressRHSDiags) {
8053 if (E->getOpcode() == BO_Comma) {
8054 // Ignore LHS but note if we could not evaluate it.
8055 if (LHSResult.Failed)
8056 return Info.noteSideEffect();
8060 if (E->isLogicalOp()) {
8062 if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) {
8063 // We were able to evaluate the LHS, see if we can get away with not
8064 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
8065 if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
8066 Success(LHSAsBool, E, LHSResult.Val);
8067 return false; // Ignore RHS
8070 LHSResult.Failed = true;
8072 // Since we weren't able to evaluate the left hand side, it
8073 // might have had side effects.
8074 if (!Info.noteSideEffect())
8077 // We can't evaluate the LHS; however, sometimes the result
8078 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
8079 // Don't ignore RHS and suppress diagnostics from this arm.
8080 SuppressRHSDiags = true;
8086 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
8087 E->getRHS()->getType()->isIntegralOrEnumerationType());
8089 if (LHSResult.Failed && !Info.noteFailure())
8090 return false; // Ignore RHS;
8095 static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index,
8097 // Compute the new offset in the appropriate width, wrapping at 64 bits.
8098 // FIXME: When compiling for a 32-bit target, we should use 32-bit
8100 assert(!LVal.hasLValuePath() && "have designator for integer lvalue");
8101 CharUnits &Offset = LVal.getLValueOffset();
8102 uint64_t Offset64 = Offset.getQuantity();
8103 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
8104 Offset = CharUnits::fromQuantity(IsSub ? Offset64 - Index64
8105 : Offset64 + Index64);
8108 bool DataRecursiveIntBinOpEvaluator::
8109 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
8110 const BinaryOperator *E, APValue &Result) {
8111 if (E->getOpcode() == BO_Comma) {
8112 if (RHSResult.Failed)
8114 Result = RHSResult.Val;
8118 if (E->isLogicalOp()) {
8119 bool lhsResult, rhsResult;
8120 bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
8121 bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);
8125 if (E->getOpcode() == BO_LOr)
8126 return Success(lhsResult || rhsResult, E, Result);
8128 return Success(lhsResult && rhsResult, E, Result);
8132 // We can't evaluate the LHS; however, sometimes the result
8133 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
8134 if (rhsResult == (E->getOpcode() == BO_LOr))
8135 return Success(rhsResult, E, Result);
8142 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
8143 E->getRHS()->getType()->isIntegralOrEnumerationType());
8145 if (LHSResult.Failed || RHSResult.Failed)
8148 const APValue &LHSVal = LHSResult.Val;
8149 const APValue &RHSVal = RHSResult.Val;
8151 // Handle cases like (unsigned long)&a + 4.
8152 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
8154 addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub);
8158 // Handle cases like 4 + (unsigned long)&a
8159 if (E->getOpcode() == BO_Add &&
8160 RHSVal.isLValue() && LHSVal.isInt()) {
8162 addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false);
8166 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
8167 // Handle (intptr_t)&&A - (intptr_t)&&B.
8168 if (!LHSVal.getLValueOffset().isZero() ||
8169 !RHSVal.getLValueOffset().isZero())
8171 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
8172 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
8173 if (!LHSExpr || !RHSExpr)
8175 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
8176 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
8177 if (!LHSAddrExpr || !RHSAddrExpr)
8179 // Make sure both labels come from the same function.
8180 if (LHSAddrExpr->getLabel()->getDeclContext() !=
8181 RHSAddrExpr->getLabel()->getDeclContext())
8183 Result = APValue(LHSAddrExpr, RHSAddrExpr);
8187 // All the remaining cases expect both operands to be an integer
8188 if (!LHSVal.isInt() || !RHSVal.isInt())
8191 // Set up the width and signedness manually, in case it can't be deduced
8192 // from the operation we're performing.
8193 // FIXME: Don't do this in the cases where we can deduce it.
8194 APSInt Value(Info.Ctx.getIntWidth(E->getType()),
8195 E->getType()->isUnsignedIntegerOrEnumerationType());
8196 if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(),
8197 RHSVal.getInt(), Value))
8199 return Success(Value, E, Result);
8202 void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
8203 Job &job = Queue.back();
8206 case Job::AnyExprKind: {
8207 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
8208 if (shouldEnqueue(Bop)) {
8209 job.Kind = Job::BinOpKind;
8210 enqueue(Bop->getLHS());
8215 EvaluateExpr(job.E, Result);
8220 case Job::BinOpKind: {
8221 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
8222 bool SuppressRHSDiags = false;
8223 if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) {
8227 if (SuppressRHSDiags)
8228 job.startSpeculativeEval(Info);
8229 job.LHSResult.swap(Result);
8230 job.Kind = Job::BinOpVisitedLHSKind;
8231 enqueue(Bop->getRHS());
8235 case Job::BinOpVisitedLHSKind: {
8236 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
8239 Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val);
8245 llvm_unreachable("Invalid Job::Kind!");
8249 /// Used when we determine that we should fail, but can keep evaluating prior to
8250 /// noting that we had a failure.
8251 class DelayedNoteFailureRAII {
8256 DelayedNoteFailureRAII(EvalInfo &Info, bool NoteFailure = true)
8257 : Info(Info), NoteFailure(NoteFailure) {}
8258 ~DelayedNoteFailureRAII() {
8260 bool ContinueAfterFailure = Info.noteFailure();
8261 (void)ContinueAfterFailure;
8262 assert(ContinueAfterFailure &&
8263 "Shouldn't have kept evaluating on failure.");
8269 bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
8270 // We don't call noteFailure immediately because the assignment happens after
8271 // we evaluate LHS and RHS.
8272 if (!Info.keepEvaluatingAfterFailure() && E->isAssignmentOp())
8275 DelayedNoteFailureRAII MaybeNoteFailureLater(Info, E->isAssignmentOp());
8276 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
8277 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
8279 QualType LHSTy = E->getLHS()->getType();
8280 QualType RHSTy = E->getRHS()->getType();
8282 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
8283 ComplexValue LHS, RHS;
8285 if (E->isAssignmentOp()) {
8287 EvaluateLValue(E->getLHS(), LV, Info);
8289 } else if (LHSTy->isRealFloatingType()) {
8290 LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info);
8292 LHS.makeComplexFloat();
8293 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
8296 LHSOK = EvaluateComplex(E->getLHS(), LHS, Info);
8298 if (!LHSOK && !Info.noteFailure())
8301 if (E->getRHS()->getType()->isRealFloatingType()) {
8302 if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK)
8304 RHS.makeComplexFloat();
8305 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
8306 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
8309 if (LHS.isComplexFloat()) {
8310 APFloat::cmpResult CR_r =
8311 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
8312 APFloat::cmpResult CR_i =
8313 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
8315 if (E->getOpcode() == BO_EQ)
8316 return Success((CR_r == APFloat::cmpEqual &&
8317 CR_i == APFloat::cmpEqual), E);
8319 assert(E->getOpcode() == BO_NE &&
8320 "Invalid complex comparison.");
8321 return Success(((CR_r == APFloat::cmpGreaterThan ||
8322 CR_r == APFloat::cmpLessThan ||
8323 CR_r == APFloat::cmpUnordered) ||
8324 (CR_i == APFloat::cmpGreaterThan ||
8325 CR_i == APFloat::cmpLessThan ||
8326 CR_i == APFloat::cmpUnordered)), E);
8329 if (E->getOpcode() == BO_EQ)
8330 return Success((LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
8331 LHS.getComplexIntImag() == RHS.getComplexIntImag()), E);
8333 assert(E->getOpcode() == BO_NE &&
8334 "Invalid compex comparison.");
8335 return Success((LHS.getComplexIntReal() != RHS.getComplexIntReal() ||
8336 LHS.getComplexIntImag() != RHS.getComplexIntImag()), E);
8341 if (LHSTy->isRealFloatingType() &&
8342 RHSTy->isRealFloatingType()) {
8343 APFloat RHS(0.0), LHS(0.0);
8345 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info);
8346 if (!LHSOK && !Info.noteFailure())
8349 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK)
8352 APFloat::cmpResult CR = LHS.compare(RHS);
8354 switch (E->getOpcode()) {
8356 llvm_unreachable("Invalid binary operator!");
8358 return Success(CR == APFloat::cmpLessThan, E);
8360 return Success(CR == APFloat::cmpGreaterThan, E);
8362 return Success(CR == APFloat::cmpLessThan || CR == APFloat::cmpEqual, E);
8364 return Success(CR == APFloat::cmpGreaterThan || CR == APFloat::cmpEqual,
8367 return Success(CR == APFloat::cmpEqual, E);
8369 return Success(CR == APFloat::cmpGreaterThan
8370 || CR == APFloat::cmpLessThan
8371 || CR == APFloat::cmpUnordered, E);
8375 if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
8376 if (E->getOpcode() == BO_Sub || E->isComparisonOp()) {
8377 LValue LHSValue, RHSValue;
8379 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
8380 if (!LHSOK && !Info.noteFailure())
8383 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
8386 // Reject differing bases from the normal codepath; we special-case
8387 // comparisons to null.
8388 if (!HasSameBase(LHSValue, RHSValue)) {
8389 if (E->getOpcode() == BO_Sub) {
8390 // Handle &&A - &&B.
8391 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
8393 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr*>();
8394 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr*>();
8395 if (!LHSExpr || !RHSExpr)
8397 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
8398 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
8399 if (!LHSAddrExpr || !RHSAddrExpr)
8401 // Make sure both labels come from the same function.
8402 if (LHSAddrExpr->getLabel()->getDeclContext() !=
8403 RHSAddrExpr->getLabel()->getDeclContext())
8405 return Success(APValue(LHSAddrExpr, RHSAddrExpr), E);
8407 // Inequalities and subtractions between unrelated pointers have
8408 // unspecified or undefined behavior.
8409 if (!E->isEqualityOp())
8411 // A constant address may compare equal to the address of a symbol.
8412 // The one exception is that address of an object cannot compare equal
8413 // to a null pointer constant.
8414 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
8415 (!RHSValue.Base && !RHSValue.Offset.isZero()))
8417 // It's implementation-defined whether distinct literals will have
8418 // distinct addresses. In clang, the result of such a comparison is
8419 // unspecified, so it is not a constant expression. However, we do know
8420 // that the address of a literal will be non-null.
8421 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
8422 LHSValue.Base && RHSValue.Base)
8424 // We can't tell whether weak symbols will end up pointing to the same
8426 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
8428 // We can't compare the address of the start of one object with the
8429 // past-the-end address of another object, per C++ DR1652.
8430 if ((LHSValue.Base && LHSValue.Offset.isZero() &&
8431 isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) ||
8432 (RHSValue.Base && RHSValue.Offset.isZero() &&
8433 isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)))
8435 // We can't tell whether an object is at the same address as another
8436 // zero sized object.
8437 if ((RHSValue.Base && isZeroSized(LHSValue)) ||
8438 (LHSValue.Base && isZeroSized(RHSValue)))
8440 // Pointers with different bases cannot represent the same object.
8441 // (Note that clang defaults to -fmerge-all-constants, which can
8442 // lead to inconsistent results for comparisons involving the address
8443 // of a constant; this generally doesn't matter in practice.)
8444 return Success(E->getOpcode() == BO_NE, E);
8447 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
8448 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
8450 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
8451 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
8453 if (E->getOpcode() == BO_Sub) {
8454 // C++11 [expr.add]p6:
8455 // Unless both pointers point to elements of the same array object, or
8456 // one past the last element of the array object, the behavior is
8458 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
8459 !AreElementsOfSameArray(getType(LHSValue.Base),
8460 LHSDesignator, RHSDesignator))
8461 CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);
8463 QualType Type = E->getLHS()->getType();
8464 QualType ElementType = Type->getAs<PointerType>()->getPointeeType();
8466 CharUnits ElementSize;
8467 if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize))
8470 // As an extension, a type may have zero size (empty struct or union in
8471 // C, array of zero length). Pointer subtraction in such cases has
8472 // undefined behavior, so is not constant.
8473 if (ElementSize.isZero()) {
8474 Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size)
8479 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
8480 // and produce incorrect results when it overflows. Such behavior
8481 // appears to be non-conforming, but is common, so perhaps we should
8482 // assume the standard intended for such cases to be undefined behavior
8483 // and check for them.
8485 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
8486 // overflow in the final conversion to ptrdiff_t.
8488 llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
8490 llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
8492 llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true), false);
8493 APSInt TrueResult = (LHS - RHS) / ElemSize;
8494 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType()));
8496 if (Result.extend(65) != TrueResult &&
8497 !HandleOverflow(Info, E, TrueResult, E->getType()))
8499 return Success(Result, E);
8502 // C++11 [expr.rel]p3:
8503 // Pointers to void (after pointer conversions) can be compared, with a
8504 // result defined as follows: If both pointers represent the same
8505 // address or are both the null pointer value, the result is true if the
8506 // operator is <= or >= and false otherwise; otherwise the result is
8508 // We interpret this as applying to pointers to *cv* void.
8509 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset &&
8510 E->isRelationalOp())
8511 CCEDiag(E, diag::note_constexpr_void_comparison);
8513 // C++11 [expr.rel]p2:
8514 // - If two pointers point to non-static data members of the same object,
8515 // or to subobjects or array elements fo such members, recursively, the
8516 // pointer to the later declared member compares greater provided the
8517 // two members have the same access control and provided their class is
8520 // - Otherwise pointer comparisons are unspecified.
8521 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
8522 E->isRelationalOp()) {
8525 FindDesignatorMismatch(getType(LHSValue.Base), LHSDesignator,
8526 RHSDesignator, WasArrayIndex);
8527 // At the point where the designators diverge, the comparison has a
8528 // specified value if:
8529 // - we are comparing array indices
8530 // - we are comparing fields of a union, or fields with the same access
8531 // Otherwise, the result is unspecified and thus the comparison is not a
8532 // constant expression.
8533 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
8534 Mismatch < RHSDesignator.Entries.size()) {
8535 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]);
8536 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]);
8538 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
8540 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
8541 << getAsBaseClass(LHSDesignator.Entries[Mismatch])
8542 << RF->getParent() << RF;
8544 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
8545 << getAsBaseClass(RHSDesignator.Entries[Mismatch])
8546 << LF->getParent() << LF;
8547 else if (!LF->getParent()->isUnion() &&
8548 LF->getAccess() != RF->getAccess())
8549 CCEDiag(E, diag::note_constexpr_pointer_comparison_differing_access)
8550 << LF << LF->getAccess() << RF << RF->getAccess()
8555 // The comparison here must be unsigned, and performed with the same
8556 // width as the pointer.
8557 unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy);
8558 uint64_t CompareLHS = LHSOffset.getQuantity();
8559 uint64_t CompareRHS = RHSOffset.getQuantity();
8560 assert(PtrSize <= 64 && "Unexpected pointer width");
8561 uint64_t Mask = ~0ULL >> (64 - PtrSize);
8565 // If there is a base and this is a relational operator, we can only
8566 // compare pointers within the object in question; otherwise, the result
8567 // depends on where the object is located in memory.
8568 if (!LHSValue.Base.isNull() && E->isRelationalOp()) {
8569 QualType BaseTy = getType(LHSValue.Base);
8570 if (BaseTy->isIncompleteType())
8572 CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy);
8573 uint64_t OffsetLimit = Size.getQuantity();
8574 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
8578 switch (E->getOpcode()) {
8579 default: llvm_unreachable("missing comparison operator");
8580 case BO_LT: return Success(CompareLHS < CompareRHS, E);
8581 case BO_GT: return Success(CompareLHS > CompareRHS, E);
8582 case BO_LE: return Success(CompareLHS <= CompareRHS, E);
8583 case BO_GE: return Success(CompareLHS >= CompareRHS, E);
8584 case BO_EQ: return Success(CompareLHS == CompareRHS, E);
8585 case BO_NE: return Success(CompareLHS != CompareRHS, E);
8590 if (LHSTy->isMemberPointerType()) {
8591 assert(E->isEqualityOp() && "unexpected member pointer operation");
8592 assert(RHSTy->isMemberPointerType() && "invalid comparison");
8594 MemberPtr LHSValue, RHSValue;
8596 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info);
8597 if (!LHSOK && !Info.noteFailure())
8600 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK)
8603 // C++11 [expr.eq]p2:
8604 // If both operands are null, they compare equal. Otherwise if only one is
8605 // null, they compare unequal.
8606 if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
8607 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
8608 return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E);
8611 // Otherwise if either is a pointer to a virtual member function, the
8612 // result is unspecified.
8613 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
8614 if (MD->isVirtual())
8615 CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
8616 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
8617 if (MD->isVirtual())
8618 CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
8620 // Otherwise they compare equal if and only if they would refer to the
8621 // same member of the same most derived object or the same subobject if
8622 // they were dereferenced with a hypothetical object of the associated
8624 bool Equal = LHSValue == RHSValue;
8625 return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E);
8628 if (LHSTy->isNullPtrType()) {
8629 assert(E->isComparisonOp() && "unexpected nullptr operation");
8630 assert(RHSTy->isNullPtrType() && "missing pointer conversion");
8631 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
8632 // are compared, the result is true of the operator is <=, >= or ==, and
8634 BinaryOperator::Opcode Opcode = E->getOpcode();
8635 return Success(Opcode == BO_EQ || Opcode == BO_LE || Opcode == BO_GE, E);
8638 assert((!LHSTy->isIntegralOrEnumerationType() ||
8639 !RHSTy->isIntegralOrEnumerationType()) &&
8640 "DataRecursiveIntBinOpEvaluator should have handled integral types");
8641 // We can't continue from here for non-integral types.
8642 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8645 /// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
8646 /// a result as the expression's type.
8647 bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
8648 const UnaryExprOrTypeTraitExpr *E) {
8649 switch(E->getKind()) {
8650 case UETT_AlignOf: {
8651 if (E->isArgumentType())
8652 return Success(GetAlignOfType(Info, E->getArgumentType()), E);
8654 return Success(GetAlignOfExpr(Info, E->getArgumentExpr()), E);
8657 case UETT_VecStep: {
8658 QualType Ty = E->getTypeOfArgument();
8660 if (Ty->isVectorType()) {
8661 unsigned n = Ty->castAs<VectorType>()->getNumElements();
8663 // The vec_step built-in functions that take a 3-component
8664 // vector return 4. (OpenCL 1.1 spec 6.11.12)
8668 return Success(n, E);
8670 return Success(1, E);
8674 QualType SrcTy = E->getTypeOfArgument();
8675 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
8676 // the result is the size of the referenced type."
8677 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
8678 SrcTy = Ref->getPointeeType();
8681 if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof))
8683 return Success(Sizeof, E);
8685 case UETT_OpenMPRequiredSimdAlign:
8686 assert(E->isArgumentType());
8688 Info.Ctx.toCharUnitsFromBits(
8689 Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType()))
8694 llvm_unreachable("unknown expr/type trait");
8697 bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
8699 unsigned n = OOE->getNumComponents();
8702 QualType CurrentType = OOE->getTypeSourceInfo()->getType();
8703 for (unsigned i = 0; i != n; ++i) {
8704 OffsetOfNode ON = OOE->getComponent(i);
8705 switch (ON.getKind()) {
8706 case OffsetOfNode::Array: {
8707 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
8709 if (!EvaluateInteger(Idx, IdxResult, Info))
8711 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
8714 CurrentType = AT->getElementType();
8715 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
8716 Result += IdxResult.getSExtValue() * ElementSize;
8720 case OffsetOfNode::Field: {
8721 FieldDecl *MemberDecl = ON.getField();
8722 const RecordType *RT = CurrentType->getAs<RecordType>();
8725 RecordDecl *RD = RT->getDecl();
8726 if (RD->isInvalidDecl()) return false;
8727 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
8728 unsigned i = MemberDecl->getFieldIndex();
8729 assert(i < RL.getFieldCount() && "offsetof field in wrong type");
8730 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
8731 CurrentType = MemberDecl->getType().getNonReferenceType();
8735 case OffsetOfNode::Identifier:
8736 llvm_unreachable("dependent __builtin_offsetof");
8738 case OffsetOfNode::Base: {
8739 CXXBaseSpecifier *BaseSpec = ON.getBase();
8740 if (BaseSpec->isVirtual())
8743 // Find the layout of the class whose base we are looking into.
8744 const RecordType *RT = CurrentType->getAs<RecordType>();
8747 RecordDecl *RD = RT->getDecl();
8748 if (RD->isInvalidDecl()) return false;
8749 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
8751 // Find the base class itself.
8752 CurrentType = BaseSpec->getType();
8753 const RecordType *BaseRT = CurrentType->getAs<RecordType>();
8757 // Add the offset to the base.
8758 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
8763 return Success(Result, OOE);
8766 bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
8767 switch (E->getOpcode()) {
8769 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
8773 // FIXME: Should extension allow i-c-e extension expressions in its scope?
8774 // If so, we could clear the diagnostic ID.
8775 return Visit(E->getSubExpr());
8777 // The result is just the value.
8778 return Visit(E->getSubExpr());
8780 if (!Visit(E->getSubExpr()))
8782 if (!Result.isInt()) return Error(E);
8783 const APSInt &Value = Result.getInt();
8784 if (Value.isSigned() && Value.isMinSignedValue() &&
8785 !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
8788 return Success(-Value, E);
8791 if (!Visit(E->getSubExpr()))
8793 if (!Result.isInt()) return Error(E);
8794 return Success(~Result.getInt(), E);
8798 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
8800 return Success(!bres, E);
8805 /// HandleCast - This is used to evaluate implicit or explicit casts where the
8806 /// result type is integer.
8807 bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
8808 const Expr *SubExpr = E->getSubExpr();
8809 QualType DestType = E->getType();
8810 QualType SrcType = SubExpr->getType();
8812 switch (E->getCastKind()) {
8813 case CK_BaseToDerived:
8814 case CK_DerivedToBase:
8815 case CK_UncheckedDerivedToBase:
8818 case CK_ArrayToPointerDecay:
8819 case CK_FunctionToPointerDecay:
8820 case CK_NullToPointer:
8821 case CK_NullToMemberPointer:
8822 case CK_BaseToDerivedMemberPointer:
8823 case CK_DerivedToBaseMemberPointer:
8824 case CK_ReinterpretMemberPointer:
8825 case CK_ConstructorConversion:
8826 case CK_IntegralToPointer:
8828 case CK_VectorSplat:
8829 case CK_IntegralToFloating:
8830 case CK_FloatingCast:
8831 case CK_CPointerToObjCPointerCast:
8832 case CK_BlockPointerToObjCPointerCast:
8833 case CK_AnyPointerToBlockPointerCast:
8834 case CK_ObjCObjectLValueCast:
8835 case CK_FloatingRealToComplex:
8836 case CK_FloatingComplexToReal:
8837 case CK_FloatingComplexCast:
8838 case CK_FloatingComplexToIntegralComplex:
8839 case CK_IntegralRealToComplex:
8840 case CK_IntegralComplexCast:
8841 case CK_IntegralComplexToFloatingComplex:
8842 case CK_BuiltinFnToFnPtr:
8843 case CK_ZeroToOCLEvent:
8844 case CK_ZeroToOCLQueue:
8845 case CK_NonAtomicToAtomic:
8846 case CK_AddressSpaceConversion:
8847 case CK_IntToOCLSampler:
8848 llvm_unreachable("invalid cast kind for integral value");
8852 case CK_LValueBitCast:
8853 case CK_ARCProduceObject:
8854 case CK_ARCConsumeObject:
8855 case CK_ARCReclaimReturnedObject:
8856 case CK_ARCExtendBlockObject:
8857 case CK_CopyAndAutoreleaseBlockObject:
8860 case CK_UserDefinedConversion:
8861 case CK_LValueToRValue:
8862 case CK_AtomicToNonAtomic:
8864 return ExprEvaluatorBaseTy::VisitCastExpr(E);
8866 case CK_MemberPointerToBoolean:
8867 case CK_PointerToBoolean:
8868 case CK_IntegralToBoolean:
8869 case CK_FloatingToBoolean:
8870 case CK_BooleanToSignedIntegral:
8871 case CK_FloatingComplexToBoolean:
8872 case CK_IntegralComplexToBoolean: {
8874 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info))
8876 uint64_t IntResult = BoolResult;
8877 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
8878 IntResult = (uint64_t)-1;
8879 return Success(IntResult, E);
8882 case CK_IntegralCast: {
8883 if (!Visit(SubExpr))
8886 if (!Result.isInt()) {
8887 // Allow casts of address-of-label differences if they are no-ops
8888 // or narrowing. (The narrowing case isn't actually guaranteed to
8889 // be constant-evaluatable except in some narrow cases which are hard
8890 // to detect here. We let it through on the assumption the user knows
8891 // what they are doing.)
8892 if (Result.isAddrLabelDiff())
8893 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
8894 // Only allow casts of lvalues if they are lossless.
8895 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
8898 return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
8899 Result.getInt()), E);
8902 case CK_PointerToIntegral: {
8903 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8906 if (!EvaluatePointer(SubExpr, LV, Info))
8909 if (LV.getLValueBase()) {
8910 // Only allow based lvalue casts if they are lossless.
8911 // FIXME: Allow a larger integer size than the pointer size, and allow
8912 // narrowing back down to pointer width in subsequent integral casts.
8913 // FIXME: Check integer type's active bits, not its type size.
8914 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
8917 LV.Designator.setInvalid();
8918 LV.moveInto(Result);
8923 if (LV.isNullPointer())
8924 V = Info.Ctx.getTargetNullPointerValue(SrcType);
8926 V = LV.getLValueOffset().getQuantity();
8928 APSInt AsInt = Info.Ctx.MakeIntValue(V, SrcType);
8929 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
8932 case CK_IntegralComplexToReal: {
8934 if (!EvaluateComplex(SubExpr, C, Info))
8936 return Success(C.getComplexIntReal(), E);
8939 case CK_FloatingToIntegral: {
8941 if (!EvaluateFloat(SubExpr, F, Info))
8945 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
8947 return Success(Value, E);
8951 llvm_unreachable("unknown cast resulting in integral value");
8954 bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
8955 if (E->getSubExpr()->getType()->isAnyComplexType()) {
8957 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
8959 if (!LV.isComplexInt())
8961 return Success(LV.getComplexIntReal(), E);
8964 return Visit(E->getSubExpr());
8967 bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
8968 if (E->getSubExpr()->getType()->isComplexIntegerType()) {
8970 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
8972 if (!LV.isComplexInt())
8974 return Success(LV.getComplexIntImag(), E);
8977 VisitIgnoredValue(E->getSubExpr());
8978 return Success(0, E);
8981 bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
8982 return Success(E->getPackLength(), E);
8985 bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
8986 return Success(E->getValue(), E);
8989 //===----------------------------------------------------------------------===//
8991 //===----------------------------------------------------------------------===//
8994 class FloatExprEvaluator
8995 : public ExprEvaluatorBase<FloatExprEvaluator> {
8998 FloatExprEvaluator(EvalInfo &info, APFloat &result)
8999 : ExprEvaluatorBaseTy(info), Result(result) {}
9001 bool Success(const APValue &V, const Expr *e) {
9002 Result = V.getFloat();
9006 bool ZeroInitialization(const Expr *E) {
9007 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
9011 bool VisitCallExpr(const CallExpr *E);
9013 bool VisitUnaryOperator(const UnaryOperator *E);
9014 bool VisitBinaryOperator(const BinaryOperator *E);
9015 bool VisitFloatingLiteral(const FloatingLiteral *E);
9016 bool VisitCastExpr(const CastExpr *E);
9018 bool VisitUnaryReal(const UnaryOperator *E);
9019 bool VisitUnaryImag(const UnaryOperator *E);
9021 // FIXME: Missing: array subscript of vector, member of vector
9023 } // end anonymous namespace
9025 static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
9026 assert(E->isRValue() && E->getType()->isRealFloatingType());
9027 return FloatExprEvaluator(Info, Result).Visit(E);
9030 static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
9034 llvm::APFloat &Result) {
9035 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
9036 if (!S) return false;
9038 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);
9042 // Treat empty strings as if they were zero.
9043 if (S->getString().empty())
9044 fill = llvm::APInt(32, 0);
9045 else if (S->getString().getAsInteger(0, fill))
9048 if (Context.getTargetInfo().isNan2008()) {
9050 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
9052 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
9054 // Prior to IEEE 754-2008, architectures were allowed to choose whether
9055 // the first bit of their significand was set for qNaN or sNaN. MIPS chose
9056 // a different encoding to what became a standard in 2008, and for pre-
9057 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
9058 // sNaN. This is now known as "legacy NaN" encoding.
9060 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
9062 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
9068 bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
9069 switch (E->getBuiltinCallee()) {
9071 return ExprEvaluatorBaseTy::VisitCallExpr(E);
9073 case Builtin::BI__builtin_huge_val:
9074 case Builtin::BI__builtin_huge_valf:
9075 case Builtin::BI__builtin_huge_vall:
9076 case Builtin::BI__builtin_inf:
9077 case Builtin::BI__builtin_inff:
9078 case Builtin::BI__builtin_infl: {
9079 const llvm::fltSemantics &Sem =
9080 Info.Ctx.getFloatTypeSemantics(E->getType());
9081 Result = llvm::APFloat::getInf(Sem);
9085 case Builtin::BI__builtin_nans:
9086 case Builtin::BI__builtin_nansf:
9087 case Builtin::BI__builtin_nansl:
9088 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
9093 case Builtin::BI__builtin_nan:
9094 case Builtin::BI__builtin_nanf:
9095 case Builtin::BI__builtin_nanl:
9096 // If this is __builtin_nan() turn this into a nan, otherwise we
9097 // can't constant fold it.
9098 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
9103 case Builtin::BI__builtin_fabs:
9104 case Builtin::BI__builtin_fabsf:
9105 case Builtin::BI__builtin_fabsl:
9106 if (!EvaluateFloat(E->getArg(0), Result, Info))
9109 if (Result.isNegative())
9110 Result.changeSign();
9113 // FIXME: Builtin::BI__builtin_powi
9114 // FIXME: Builtin::BI__builtin_powif
9115 // FIXME: Builtin::BI__builtin_powil
9117 case Builtin::BI__builtin_copysign:
9118 case Builtin::BI__builtin_copysignf:
9119 case Builtin::BI__builtin_copysignl: {
9121 if (!EvaluateFloat(E->getArg(0), Result, Info) ||
9122 !EvaluateFloat(E->getArg(1), RHS, Info))
9124 Result.copySign(RHS);
9130 bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
9131 if (E->getSubExpr()->getType()->isAnyComplexType()) {
9133 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
9135 Result = CV.FloatReal;
9139 return Visit(E->getSubExpr());
9142 bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
9143 if (E->getSubExpr()->getType()->isAnyComplexType()) {
9145 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
9147 Result = CV.FloatImag;
9151 VisitIgnoredValue(E->getSubExpr());
9152 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
9153 Result = llvm::APFloat::getZero(Sem);
9157 bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
9158 switch (E->getOpcode()) {
9159 default: return Error(E);
9161 return EvaluateFloat(E->getSubExpr(), Result, Info);
9163 if (!EvaluateFloat(E->getSubExpr(), Result, Info))
9165 Result.changeSign();
9170 bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
9171 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
9172 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
9175 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info);
9176 if (!LHSOK && !Info.noteFailure())
9178 return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK &&
9179 handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS);
9182 bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
9183 Result = E->getValue();
9187 bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
9188 const Expr* SubExpr = E->getSubExpr();
9190 switch (E->getCastKind()) {
9192 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9194 case CK_IntegralToFloating: {
9196 return EvaluateInteger(SubExpr, IntResult, Info) &&
9197 HandleIntToFloatCast(Info, E, SubExpr->getType(), IntResult,
9198 E->getType(), Result);
9201 case CK_FloatingCast: {
9202 if (!Visit(SubExpr))
9204 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
9208 case CK_FloatingComplexToReal: {
9210 if (!EvaluateComplex(SubExpr, V, Info))
9212 Result = V.getComplexFloatReal();
9218 //===----------------------------------------------------------------------===//
9219 // Complex Evaluation (for float and integer)
9220 //===----------------------------------------------------------------------===//
9223 class ComplexExprEvaluator
9224 : public ExprEvaluatorBase<ComplexExprEvaluator> {
9225 ComplexValue &Result;
9228 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
9229 : ExprEvaluatorBaseTy(info), Result(Result) {}
9231 bool Success(const APValue &V, const Expr *e) {
9236 bool ZeroInitialization(const Expr *E);
9238 //===--------------------------------------------------------------------===//
9240 //===--------------------------------------------------------------------===//
9242 bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
9243 bool VisitCastExpr(const CastExpr *E);
9244 bool VisitBinaryOperator(const BinaryOperator *E);
9245 bool VisitUnaryOperator(const UnaryOperator *E);
9246 bool VisitInitListExpr(const InitListExpr *E);
9248 } // end anonymous namespace
9250 static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
9252 assert(E->isRValue() && E->getType()->isAnyComplexType());
9253 return ComplexExprEvaluator(Info, Result).Visit(E);
9256 bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
9257 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
9258 if (ElemTy->isRealFloatingType()) {
9259 Result.makeComplexFloat();
9260 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy));
9261 Result.FloatReal = Zero;
9262 Result.FloatImag = Zero;
9264 Result.makeComplexInt();
9265 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy);
9266 Result.IntReal = Zero;
9267 Result.IntImag = Zero;
9272 bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
9273 const Expr* SubExpr = E->getSubExpr();
9275 if (SubExpr->getType()->isRealFloatingType()) {
9276 Result.makeComplexFloat();
9277 APFloat &Imag = Result.FloatImag;
9278 if (!EvaluateFloat(SubExpr, Imag, Info))
9281 Result.FloatReal = APFloat(Imag.getSemantics());
9284 assert(SubExpr->getType()->isIntegerType() &&
9285 "Unexpected imaginary literal.");
9287 Result.makeComplexInt();
9288 APSInt &Imag = Result.IntImag;
9289 if (!EvaluateInteger(SubExpr, Imag, Info))
9292 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
9297 bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
9299 switch (E->getCastKind()) {
9301 case CK_BaseToDerived:
9302 case CK_DerivedToBase:
9303 case CK_UncheckedDerivedToBase:
9306 case CK_ArrayToPointerDecay:
9307 case CK_FunctionToPointerDecay:
9308 case CK_NullToPointer:
9309 case CK_NullToMemberPointer:
9310 case CK_BaseToDerivedMemberPointer:
9311 case CK_DerivedToBaseMemberPointer:
9312 case CK_MemberPointerToBoolean:
9313 case CK_ReinterpretMemberPointer:
9314 case CK_ConstructorConversion:
9315 case CK_IntegralToPointer:
9316 case CK_PointerToIntegral:
9317 case CK_PointerToBoolean:
9319 case CK_VectorSplat:
9320 case CK_IntegralCast:
9321 case CK_BooleanToSignedIntegral:
9322 case CK_IntegralToBoolean:
9323 case CK_IntegralToFloating:
9324 case CK_FloatingToIntegral:
9325 case CK_FloatingToBoolean:
9326 case CK_FloatingCast:
9327 case CK_CPointerToObjCPointerCast:
9328 case CK_BlockPointerToObjCPointerCast:
9329 case CK_AnyPointerToBlockPointerCast:
9330 case CK_ObjCObjectLValueCast:
9331 case CK_FloatingComplexToReal:
9332 case CK_FloatingComplexToBoolean:
9333 case CK_IntegralComplexToReal:
9334 case CK_IntegralComplexToBoolean:
9335 case CK_ARCProduceObject:
9336 case CK_ARCConsumeObject:
9337 case CK_ARCReclaimReturnedObject:
9338 case CK_ARCExtendBlockObject:
9339 case CK_CopyAndAutoreleaseBlockObject:
9340 case CK_BuiltinFnToFnPtr:
9341 case CK_ZeroToOCLEvent:
9342 case CK_ZeroToOCLQueue:
9343 case CK_NonAtomicToAtomic:
9344 case CK_AddressSpaceConversion:
9345 case CK_IntToOCLSampler:
9346 llvm_unreachable("invalid cast kind for complex value");
9348 case CK_LValueToRValue:
9349 case CK_AtomicToNonAtomic:
9351 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9354 case CK_LValueBitCast:
9355 case CK_UserDefinedConversion:
9358 case CK_FloatingRealToComplex: {
9359 APFloat &Real = Result.FloatReal;
9360 if (!EvaluateFloat(E->getSubExpr(), Real, Info))
9363 Result.makeComplexFloat();
9364 Result.FloatImag = APFloat(Real.getSemantics());
9368 case CK_FloatingComplexCast: {
9369 if (!Visit(E->getSubExpr()))
9372 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9374 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9376 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
9377 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
9380 case CK_FloatingComplexToIntegralComplex: {
9381 if (!Visit(E->getSubExpr()))
9384 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9386 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9387 Result.makeComplexInt();
9388 return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
9389 To, Result.IntReal) &&
9390 HandleFloatToIntCast(Info, E, From, Result.FloatImag,
9391 To, Result.IntImag);
9394 case CK_IntegralRealToComplex: {
9395 APSInt &Real = Result.IntReal;
9396 if (!EvaluateInteger(E->getSubExpr(), Real, Info))
9399 Result.makeComplexInt();
9400 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
9404 case CK_IntegralComplexCast: {
9405 if (!Visit(E->getSubExpr()))
9408 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9410 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9412 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
9413 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
9417 case CK_IntegralComplexToFloatingComplex: {
9418 if (!Visit(E->getSubExpr()))
9421 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
9423 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
9424 Result.makeComplexFloat();
9425 return HandleIntToFloatCast(Info, E, From, Result.IntReal,
9426 To, Result.FloatReal) &&
9427 HandleIntToFloatCast(Info, E, From, Result.IntImag,
9428 To, Result.FloatImag);
9432 llvm_unreachable("unknown cast resulting in complex value");
9435 bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
9436 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
9437 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
9439 // Track whether the LHS or RHS is real at the type system level. When this is
9440 // the case we can simplify our evaluation strategy.
9441 bool LHSReal = false, RHSReal = false;
9444 if (E->getLHS()->getType()->isRealFloatingType()) {
9446 APFloat &Real = Result.FloatReal;
9447 LHSOK = EvaluateFloat(E->getLHS(), Real, Info);
9449 Result.makeComplexFloat();
9450 Result.FloatImag = APFloat(Real.getSemantics());
9453 LHSOK = Visit(E->getLHS());
9455 if (!LHSOK && !Info.noteFailure())
9459 if (E->getRHS()->getType()->isRealFloatingType()) {
9461 APFloat &Real = RHS.FloatReal;
9462 if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK)
9464 RHS.makeComplexFloat();
9465 RHS.FloatImag = APFloat(Real.getSemantics());
9466 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
9469 assert(!(LHSReal && RHSReal) &&
9470 "Cannot have both operands of a complex operation be real.");
9471 switch (E->getOpcode()) {
9472 default: return Error(E);
9474 if (Result.isComplexFloat()) {
9475 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
9476 APFloat::rmNearestTiesToEven);
9478 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
9480 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
9481 APFloat::rmNearestTiesToEven);
9483 Result.getComplexIntReal() += RHS.getComplexIntReal();
9484 Result.getComplexIntImag() += RHS.getComplexIntImag();
9488 if (Result.isComplexFloat()) {
9489 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
9490 APFloat::rmNearestTiesToEven);
9492 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
9493 Result.getComplexFloatImag().changeSign();
9494 } else if (!RHSReal) {
9495 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
9496 APFloat::rmNearestTiesToEven);
9499 Result.getComplexIntReal() -= RHS.getComplexIntReal();
9500 Result.getComplexIntImag() -= RHS.getComplexIntImag();
9504 if (Result.isComplexFloat()) {
9505 // This is an implementation of complex multiplication according to the
9506 // constraints laid out in C11 Annex G. The implemantion uses the
9507 // following naming scheme:
9508 // (a + ib) * (c + id)
9509 ComplexValue LHS = Result;
9510 APFloat &A = LHS.getComplexFloatReal();
9511 APFloat &B = LHS.getComplexFloatImag();
9512 APFloat &C = RHS.getComplexFloatReal();
9513 APFloat &D = RHS.getComplexFloatImag();
9514 APFloat &ResR = Result.getComplexFloatReal();
9515 APFloat &ResI = Result.getComplexFloatImag();
9517 assert(!RHSReal && "Cannot have two real operands for a complex op!");
9520 } else if (RHSReal) {
9524 // In the fully general case, we need to handle NaNs and infinities
9532 if (ResR.isNaN() && ResI.isNaN()) {
9533 bool Recalc = false;
9534 if (A.isInfinity() || B.isInfinity()) {
9535 A = APFloat::copySign(
9536 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
9537 B = APFloat::copySign(
9538 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
9540 C = APFloat::copySign(APFloat(C.getSemantics()), C);
9542 D = APFloat::copySign(APFloat(D.getSemantics()), D);
9545 if (C.isInfinity() || D.isInfinity()) {
9546 C = APFloat::copySign(
9547 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
9548 D = APFloat::copySign(
9549 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
9551 A = APFloat::copySign(APFloat(A.getSemantics()), A);
9553 B = APFloat::copySign(APFloat(B.getSemantics()), B);
9556 if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
9557 AD.isInfinity() || BC.isInfinity())) {
9559 A = APFloat::copySign(APFloat(A.getSemantics()), A);
9561 B = APFloat::copySign(APFloat(B.getSemantics()), B);
9563 C = APFloat::copySign(APFloat(C.getSemantics()), C);
9565 D = APFloat::copySign(APFloat(D.getSemantics()), D);
9569 ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
9570 ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
9575 ComplexValue LHS = Result;
9576 Result.getComplexIntReal() =
9577 (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
9578 LHS.getComplexIntImag() * RHS.getComplexIntImag());
9579 Result.getComplexIntImag() =
9580 (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
9581 LHS.getComplexIntImag() * RHS.getComplexIntReal());
9585 if (Result.isComplexFloat()) {
9586 // This is an implementation of complex division according to the
9587 // constraints laid out in C11 Annex G. The implemantion uses the
9588 // following naming scheme:
9589 // (a + ib) / (c + id)
9590 ComplexValue LHS = Result;
9591 APFloat &A = LHS.getComplexFloatReal();
9592 APFloat &B = LHS.getComplexFloatImag();
9593 APFloat &C = RHS.getComplexFloatReal();
9594 APFloat &D = RHS.getComplexFloatImag();
9595 APFloat &ResR = Result.getComplexFloatReal();
9596 APFloat &ResI = Result.getComplexFloatImag();
9602 // No real optimizations we can do here, stub out with zero.
9603 B = APFloat::getZero(A.getSemantics());
9606 APFloat MaxCD = maxnum(abs(C), abs(D));
9607 if (MaxCD.isFinite()) {
9608 DenomLogB = ilogb(MaxCD);
9609 C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven);
9610 D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven);
9612 APFloat Denom = C * C + D * D;
9613 ResR = scalbn((A * C + B * D) / Denom, -DenomLogB,
9614 APFloat::rmNearestTiesToEven);
9615 ResI = scalbn((B * C - A * D) / Denom, -DenomLogB,
9616 APFloat::rmNearestTiesToEven);
9617 if (ResR.isNaN() && ResI.isNaN()) {
9618 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
9619 ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A;
9620 ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B;
9621 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
9623 A = APFloat::copySign(
9624 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
9625 B = APFloat::copySign(
9626 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
9627 ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D);
9628 ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D);
9629 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
9630 C = APFloat::copySign(
9631 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
9632 D = APFloat::copySign(
9633 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
9634 ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D);
9635 ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D);
9640 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
9641 return Error(E, diag::note_expr_divide_by_zero);
9643 ComplexValue LHS = Result;
9644 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
9645 RHS.getComplexIntImag() * RHS.getComplexIntImag();
9646 Result.getComplexIntReal() =
9647 (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
9648 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
9649 Result.getComplexIntImag() =
9650 (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
9651 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
9659 bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
9660 // Get the operand value into 'Result'.
9661 if (!Visit(E->getSubExpr()))
9664 switch (E->getOpcode()) {
9670 // The result is always just the subexpr.
9673 if (Result.isComplexFloat()) {
9674 Result.getComplexFloatReal().changeSign();
9675 Result.getComplexFloatImag().changeSign();
9678 Result.getComplexIntReal() = -Result.getComplexIntReal();
9679 Result.getComplexIntImag() = -Result.getComplexIntImag();
9683 if (Result.isComplexFloat())
9684 Result.getComplexFloatImag().changeSign();
9686 Result.getComplexIntImag() = -Result.getComplexIntImag();
9691 bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
9692 if (E->getNumInits() == 2) {
9693 if (E->getType()->isComplexType()) {
9694 Result.makeComplexFloat();
9695 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info))
9697 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info))
9700 Result.makeComplexInt();
9701 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info))
9703 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info))
9708 return ExprEvaluatorBaseTy::VisitInitListExpr(E);
9711 //===----------------------------------------------------------------------===//
9712 // Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
9713 // implicit conversion.
9714 //===----------------------------------------------------------------------===//
9717 class AtomicExprEvaluator :
9718 public ExprEvaluatorBase<AtomicExprEvaluator> {
9722 AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
9723 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
9725 bool Success(const APValue &V, const Expr *E) {
9730 bool ZeroInitialization(const Expr *E) {
9731 ImplicitValueInitExpr VIE(
9732 E->getType()->castAs<AtomicType>()->getValueType());
9733 // For atomic-qualified class (and array) types in C++, initialize the
9734 // _Atomic-wrapped subobject directly, in-place.
9735 return This ? EvaluateInPlace(Result, Info, *This, &VIE)
9736 : Evaluate(Result, Info, &VIE);
9739 bool VisitCastExpr(const CastExpr *E) {
9740 switch (E->getCastKind()) {
9742 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9743 case CK_NonAtomicToAtomic:
9744 return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr())
9745 : Evaluate(Result, Info, E->getSubExpr());
9749 } // end anonymous namespace
9751 static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
9753 assert(E->isRValue() && E->getType()->isAtomicType());
9754 return AtomicExprEvaluator(Info, This, Result).Visit(E);
9757 //===----------------------------------------------------------------------===//
9758 // Void expression evaluation, primarily for a cast to void on the LHS of a
9760 //===----------------------------------------------------------------------===//
9763 class VoidExprEvaluator
9764 : public ExprEvaluatorBase<VoidExprEvaluator> {
9766 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
9768 bool Success(const APValue &V, const Expr *e) { return true; }
9770 bool VisitCastExpr(const CastExpr *E) {
9771 switch (E->getCastKind()) {
9773 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9775 VisitIgnoredValue(E->getSubExpr());
9780 bool VisitCallExpr(const CallExpr *E) {
9781 switch (E->getBuiltinCallee()) {
9783 return ExprEvaluatorBaseTy::VisitCallExpr(E);
9784 case Builtin::BI__assume:
9785 case Builtin::BI__builtin_assume:
9786 // The argument is not evaluated!
9791 } // end anonymous namespace
9793 static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
9794 assert(E->isRValue() && E->getType()->isVoidType());
9795 return VoidExprEvaluator(Info).Visit(E);
9798 //===----------------------------------------------------------------------===//
9799 // Top level Expr::EvaluateAsRValue method.
9800 //===----------------------------------------------------------------------===//
9802 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
9803 // In C, function designators are not lvalues, but we evaluate them as if they
9805 QualType T = E->getType();
9806 if (E->isGLValue() || T->isFunctionType()) {
9808 if (!EvaluateLValue(E, LV, Info))
9810 LV.moveInto(Result);
9811 } else if (T->isVectorType()) {
9812 if (!EvaluateVector(E, Result, Info))
9814 } else if (T->isIntegralOrEnumerationType()) {
9815 if (!IntExprEvaluator(Info, Result).Visit(E))
9817 } else if (T->hasPointerRepresentation()) {
9819 if (!EvaluatePointer(E, LV, Info))
9821 LV.moveInto(Result);
9822 } else if (T->isRealFloatingType()) {
9823 llvm::APFloat F(0.0);
9824 if (!EvaluateFloat(E, F, Info))
9826 Result = APValue(F);
9827 } else if (T->isAnyComplexType()) {
9829 if (!EvaluateComplex(E, C, Info))
9832 } else if (T->isMemberPointerType()) {
9834 if (!EvaluateMemberPointer(E, P, Info))
9838 } else if (T->isArrayType()) {
9840 LV.set(E, Info.CurrentCall->Index);
9841 APValue &Value = Info.CurrentCall->createTemporary(E, false);
9842 if (!EvaluateArray(E, LV, Value, Info))
9845 } else if (T->isRecordType()) {
9847 LV.set(E, Info.CurrentCall->Index);
9848 APValue &Value = Info.CurrentCall->createTemporary(E, false);
9849 if (!EvaluateRecord(E, LV, Value, Info))
9852 } else if (T->isVoidType()) {
9853 if (!Info.getLangOpts().CPlusPlus11)
9854 Info.CCEDiag(E, diag::note_constexpr_nonliteral)
9856 if (!EvaluateVoid(E, Info))
9858 } else if (T->isAtomicType()) {
9859 QualType Unqual = T.getAtomicUnqualifiedType();
9860 if (Unqual->isArrayType() || Unqual->isRecordType()) {
9862 LV.set(E, Info.CurrentCall->Index);
9863 APValue &Value = Info.CurrentCall->createTemporary(E, false);
9864 if (!EvaluateAtomic(E, &LV, Value, Info))
9867 if (!EvaluateAtomic(E, nullptr, Result, Info))
9870 } else if (Info.getLangOpts().CPlusPlus11) {
9871 Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
9874 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
9881 /// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
9882 /// cases, the in-place evaluation is essential, since later initializers for
9883 /// an object can indirectly refer to subobjects which were initialized earlier.
9884 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
9885 const Expr *E, bool AllowNonLiteralTypes) {
9886 assert(!E->isValueDependent());
9888 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
9891 if (E->isRValue()) {
9892 // Evaluate arrays and record types in-place, so that later initializers can
9893 // refer to earlier-initialized members of the object.
9894 QualType T = E->getType();
9895 if (T->isArrayType())
9896 return EvaluateArray(E, This, Result, Info);
9897 else if (T->isRecordType())
9898 return EvaluateRecord(E, This, Result, Info);
9899 else if (T->isAtomicType()) {
9900 QualType Unqual = T.getAtomicUnqualifiedType();
9901 if (Unqual->isArrayType() || Unqual->isRecordType())
9902 return EvaluateAtomic(E, &This, Result, Info);
9906 // For any other type, in-place evaluation is unimportant.
9907 return Evaluate(Result, Info, E);
9910 /// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
9911 /// lvalue-to-rvalue cast if it is an lvalue.
9912 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
9913 if (E->getType().isNull())
9916 if (!CheckLiteralType(Info, E))
9919 if (!::Evaluate(Result, Info, E))
9922 if (E->isGLValue()) {
9924 LV.setFrom(Info.Ctx, Result);
9925 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
9929 // Check this core constant expression is a constant expression.
9930 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result);
9933 static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
9934 const ASTContext &Ctx, bool &IsConst,
9935 bool IsCheckingForOverflow) {
9936 // Fast-path evaluations of integer literals, since we sometimes see files
9937 // containing vast quantities of these.
9938 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) {
9939 Result.Val = APValue(APSInt(L->getValue(),
9940 L->getType()->isUnsignedIntegerType()));
9945 // This case should be rare, but we need to check it before we check on
9947 if (Exp->getType().isNull()) {
9952 // FIXME: Evaluating values of large array and record types can cause
9953 // performance problems. Only do so in C++11 for now.
9954 if (Exp->isRValue() && (Exp->getType()->isArrayType() ||
9955 Exp->getType()->isRecordType()) &&
9956 !Ctx.getLangOpts().CPlusPlus11 && !IsCheckingForOverflow) {
9964 /// EvaluateAsRValue - Return true if this is a constant which we can fold using
9965 /// any crazy technique (that has nothing to do with language standards) that
9966 /// we want to. If this function returns true, it returns the folded constant
9967 /// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
9968 /// will be applied to the result.
9969 bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const {
9971 if (FastEvaluateAsRValue(this, Result, Ctx, IsConst, false))
9974 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
9975 return ::EvaluateAsRValue(Info, this, Result.Val);
9978 bool Expr::EvaluateAsBooleanCondition(bool &Result,
9979 const ASTContext &Ctx) const {
9981 return EvaluateAsRValue(Scratch, Ctx) &&
9982 HandleConversionToBool(Scratch.Val, Result);
9985 static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
9986 Expr::SideEffectsKind SEK) {
9987 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
9988 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
9991 bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx,
9992 SideEffectsKind AllowSideEffects) const {
9993 if (!getType()->isIntegralOrEnumerationType())
9996 EvalResult ExprResult;
9997 if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isInt() ||
9998 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
10001 Result = ExprResult.Val.getInt();
10005 bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
10006 SideEffectsKind AllowSideEffects) const {
10007 if (!getType()->isRealFloatingType())
10010 EvalResult ExprResult;
10011 if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isFloat() ||
10012 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
10015 Result = ExprResult.Val.getFloat();
10019 bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const {
10020 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
10023 if (!EvaluateLValue(this, LV, Info) || Result.HasSideEffects ||
10024 !CheckLValueConstantExpression(Info, getExprLoc(),
10025 Ctx.getLValueReferenceType(getType()), LV))
10028 LV.moveInto(Result.Val);
10032 bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
10034 SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
10035 // FIXME: Evaluating initializers for large array and record types can cause
10036 // performance problems. Only do so in C++11 for now.
10037 if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
10038 !Ctx.getLangOpts().CPlusPlus11)
10041 Expr::EvalStatus EStatus;
10042 EStatus.Diag = &Notes;
10044 EvalInfo InitInfo(Ctx, EStatus, VD->isConstexpr()
10045 ? EvalInfo::EM_ConstantExpression
10046 : EvalInfo::EM_ConstantFold);
10047 InitInfo.setEvaluatingDecl(VD, Value);
10052 // C++11 [basic.start.init]p2:
10053 // Variables with static storage duration or thread storage duration shall be
10054 // zero-initialized before any other initialization takes place.
10055 // This behavior is not present in C.
10056 if (Ctx.getLangOpts().CPlusPlus && !VD->hasLocalStorage() &&
10057 !VD->getType()->isReferenceType()) {
10058 ImplicitValueInitExpr VIE(VD->getType());
10059 if (!EvaluateInPlace(Value, InitInfo, LVal, &VIE,
10060 /*AllowNonLiteralTypes=*/true))
10064 if (!EvaluateInPlace(Value, InitInfo, LVal, this,
10065 /*AllowNonLiteralTypes=*/true) ||
10066 EStatus.HasSideEffects)
10069 return CheckConstantExpression(InitInfo, VD->getLocation(), VD->getType(),
10073 /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
10074 /// constant folded, but discard the result.
10075 bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
10077 return EvaluateAsRValue(Result, Ctx) &&
10078 !hasUnacceptableSideEffect(Result, SEK);
10081 APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
10082 SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
10083 EvalResult EvalResult;
10084 EvalResult.Diag = Diag;
10085 bool Result = EvaluateAsRValue(EvalResult, Ctx);
10087 assert(Result && "Could not evaluate expression");
10088 assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer");
10090 return EvalResult.Val.getInt();
10093 void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
10095 EvalResult EvalResult;
10096 if (!FastEvaluateAsRValue(this, EvalResult, Ctx, IsConst, true)) {
10097 EvalInfo Info(Ctx, EvalResult, EvalInfo::EM_EvaluateForOverflow);
10098 (void)::EvaluateAsRValue(Info, this, EvalResult.Val);
10102 bool Expr::EvalResult::isGlobalLValue() const {
10103 assert(Val.isLValue());
10104 return IsGlobalLValue(Val.getLValueBase());
10108 /// isIntegerConstantExpr - this recursive routine will test if an expression is
10109 /// an integer constant expression.
10111 /// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
10114 // CheckICE - This function does the fundamental ICE checking: the returned
10115 // ICEDiag contains an ICEKind indicating whether the expression is an ICE,
10116 // and a (possibly null) SourceLocation indicating the location of the problem.
10118 // Note that to reduce code duplication, this helper does no evaluation
10119 // itself; the caller checks whether the expression is evaluatable, and
10120 // in the rare cases where CheckICE actually cares about the evaluated
10121 // value, it calls into Evaluate.
10126 /// This expression is an ICE.
10128 /// This expression is not an ICE, but if it isn't evaluated, it's
10129 /// a legal subexpression for an ICE. This return value is used to handle
10130 /// the comma operator in C99 mode, and non-constant subexpressions.
10131 IK_ICEIfUnevaluated,
10132 /// This expression is not an ICE, and is not a legal subexpression for one.
10138 SourceLocation Loc;
10140 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
10145 static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }
10147 static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }
10149 static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
10150 Expr::EvalResult EVResult;
10151 if (!E->EvaluateAsRValue(EVResult, Ctx) || EVResult.HasSideEffects ||
10152 !EVResult.Val.isInt())
10153 return ICEDiag(IK_NotICE, E->getLocStart());
10158 static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
10159 assert(!E->isValueDependent() && "Should not see value dependent exprs!");
10160 if (!E->getType()->isIntegralOrEnumerationType())
10161 return ICEDiag(IK_NotICE, E->getLocStart());
10163 switch (E->getStmtClass()) {
10164 #define ABSTRACT_STMT(Node)
10165 #define STMT(Node, Base) case Expr::Node##Class:
10166 #define EXPR(Node, Base)
10167 #include "clang/AST/StmtNodes.inc"
10168 case Expr::PredefinedExprClass:
10169 case Expr::FloatingLiteralClass:
10170 case Expr::ImaginaryLiteralClass:
10171 case Expr::StringLiteralClass:
10172 case Expr::ArraySubscriptExprClass:
10173 case Expr::OMPArraySectionExprClass:
10174 case Expr::MemberExprClass:
10175 case Expr::CompoundAssignOperatorClass:
10176 case Expr::CompoundLiteralExprClass:
10177 case Expr::ExtVectorElementExprClass:
10178 case Expr::DesignatedInitExprClass:
10179 case Expr::ArrayInitLoopExprClass:
10180 case Expr::ArrayInitIndexExprClass:
10181 case Expr::NoInitExprClass:
10182 case Expr::DesignatedInitUpdateExprClass:
10183 case Expr::ImplicitValueInitExprClass:
10184 case Expr::ParenListExprClass:
10185 case Expr::VAArgExprClass:
10186 case Expr::AddrLabelExprClass:
10187 case Expr::StmtExprClass:
10188 case Expr::CXXMemberCallExprClass:
10189 case Expr::CUDAKernelCallExprClass:
10190 case Expr::CXXDynamicCastExprClass:
10191 case Expr::CXXTypeidExprClass:
10192 case Expr::CXXUuidofExprClass:
10193 case Expr::MSPropertyRefExprClass:
10194 case Expr::MSPropertySubscriptExprClass:
10195 case Expr::CXXNullPtrLiteralExprClass:
10196 case Expr::UserDefinedLiteralClass:
10197 case Expr::CXXThisExprClass:
10198 case Expr::CXXThrowExprClass:
10199 case Expr::CXXNewExprClass:
10200 case Expr::CXXDeleteExprClass:
10201 case Expr::CXXPseudoDestructorExprClass:
10202 case Expr::UnresolvedLookupExprClass:
10203 case Expr::TypoExprClass:
10204 case Expr::DependentScopeDeclRefExprClass:
10205 case Expr::CXXConstructExprClass:
10206 case Expr::CXXInheritedCtorInitExprClass:
10207 case Expr::CXXStdInitializerListExprClass:
10208 case Expr::CXXBindTemporaryExprClass:
10209 case Expr::ExprWithCleanupsClass:
10210 case Expr::CXXTemporaryObjectExprClass:
10211 case Expr::CXXUnresolvedConstructExprClass:
10212 case Expr::CXXDependentScopeMemberExprClass:
10213 case Expr::UnresolvedMemberExprClass:
10214 case Expr::ObjCStringLiteralClass:
10215 case Expr::ObjCBoxedExprClass:
10216 case Expr::ObjCArrayLiteralClass:
10217 case Expr::ObjCDictionaryLiteralClass:
10218 case Expr::ObjCEncodeExprClass:
10219 case Expr::ObjCMessageExprClass:
10220 case Expr::ObjCSelectorExprClass:
10221 case Expr::ObjCProtocolExprClass:
10222 case Expr::ObjCIvarRefExprClass:
10223 case Expr::ObjCPropertyRefExprClass:
10224 case Expr::ObjCSubscriptRefExprClass:
10225 case Expr::ObjCIsaExprClass:
10226 case Expr::ObjCAvailabilityCheckExprClass:
10227 case Expr::ShuffleVectorExprClass:
10228 case Expr::ConvertVectorExprClass:
10229 case Expr::BlockExprClass:
10230 case Expr::NoStmtClass:
10231 case Expr::OpaqueValueExprClass:
10232 case Expr::PackExpansionExprClass:
10233 case Expr::SubstNonTypeTemplateParmPackExprClass:
10234 case Expr::FunctionParmPackExprClass:
10235 case Expr::AsTypeExprClass:
10236 case Expr::ObjCIndirectCopyRestoreExprClass:
10237 case Expr::MaterializeTemporaryExprClass:
10238 case Expr::PseudoObjectExprClass:
10239 case Expr::AtomicExprClass:
10240 case Expr::LambdaExprClass:
10241 case Expr::CXXFoldExprClass:
10242 case Expr::CoawaitExprClass:
10243 case Expr::DependentCoawaitExprClass:
10244 case Expr::CoyieldExprClass:
10245 return ICEDiag(IK_NotICE, E->getLocStart());
10247 case Expr::InitListExprClass: {
10248 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
10249 // form "T x = { a };" is equivalent to "T x = a;".
10250 // Unless we're initializing a reference, T is a scalar as it is known to be
10251 // of integral or enumeration type.
10253 if (cast<InitListExpr>(E)->getNumInits() == 1)
10254 return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx);
10255 return ICEDiag(IK_NotICE, E->getLocStart());
10258 case Expr::SizeOfPackExprClass:
10259 case Expr::GNUNullExprClass:
10260 // GCC considers the GNU __null value to be an integral constant expression.
10263 case Expr::SubstNonTypeTemplateParmExprClass:
10265 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
10267 case Expr::ParenExprClass:
10268 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
10269 case Expr::GenericSelectionExprClass:
10270 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
10271 case Expr::IntegerLiteralClass:
10272 case Expr::CharacterLiteralClass:
10273 case Expr::ObjCBoolLiteralExprClass:
10274 case Expr::CXXBoolLiteralExprClass:
10275 case Expr::CXXScalarValueInitExprClass:
10276 case Expr::TypeTraitExprClass:
10277 case Expr::ArrayTypeTraitExprClass:
10278 case Expr::ExpressionTraitExprClass:
10279 case Expr::CXXNoexceptExprClass:
10281 case Expr::CallExprClass:
10282 case Expr::CXXOperatorCallExprClass: {
10283 // C99 6.6/3 allows function calls within unevaluated subexpressions of
10284 // constant expressions, but they can never be ICEs because an ICE cannot
10285 // contain an operand of (pointer to) function type.
10286 const CallExpr *CE = cast<CallExpr>(E);
10287 if (CE->getBuiltinCallee())
10288 return CheckEvalInICE(E, Ctx);
10289 return ICEDiag(IK_NotICE, E->getLocStart());
10291 case Expr::DeclRefExprClass: {
10292 if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl()))
10294 const ValueDecl *D = dyn_cast<ValueDecl>(cast<DeclRefExpr>(E)->getDecl());
10295 if (Ctx.getLangOpts().CPlusPlus &&
10296 D && IsConstNonVolatile(D->getType())) {
10297 // Parameter variables are never constants. Without this check,
10298 // getAnyInitializer() can find a default argument, which leads
10300 if (isa<ParmVarDecl>(D))
10301 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10304 // A variable of non-volatile const-qualified integral or enumeration
10305 // type initialized by an ICE can be used in ICEs.
10306 if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) {
10307 if (!Dcl->getType()->isIntegralOrEnumerationType())
10308 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10311 // Look for a declaration of this variable that has an initializer, and
10312 // check whether it is an ICE.
10313 if (Dcl->getAnyInitializer(VD) && VD->checkInitIsICE())
10316 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10319 return ICEDiag(IK_NotICE, E->getLocStart());
10321 case Expr::UnaryOperatorClass: {
10322 const UnaryOperator *Exp = cast<UnaryOperator>(E);
10323 switch (Exp->getOpcode()) {
10331 // C99 6.6/3 allows increment and decrement within unevaluated
10332 // subexpressions of constant expressions, but they can never be ICEs
10333 // because an ICE cannot contain an lvalue operand.
10334 return ICEDiag(IK_NotICE, E->getLocStart());
10342 return CheckICE(Exp->getSubExpr(), Ctx);
10345 // OffsetOf falls through here.
10347 case Expr::OffsetOfExprClass: {
10348 // Note that per C99, offsetof must be an ICE. And AFAIK, using
10349 // EvaluateAsRValue matches the proposed gcc behavior for cases like
10350 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect
10351 // compliance: we should warn earlier for offsetof expressions with
10352 // array subscripts that aren't ICEs, and if the array subscripts
10353 // are ICEs, the value of the offsetof must be an integer constant.
10354 return CheckEvalInICE(E, Ctx);
10356 case Expr::UnaryExprOrTypeTraitExprClass: {
10357 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
10358 if ((Exp->getKind() == UETT_SizeOf) &&
10359 Exp->getTypeOfArgument()->isVariableArrayType())
10360 return ICEDiag(IK_NotICE, E->getLocStart());
10363 case Expr::BinaryOperatorClass: {
10364 const BinaryOperator *Exp = cast<BinaryOperator>(E);
10365 switch (Exp->getOpcode()) {
10379 // C99 6.6/3 allows assignments within unevaluated subexpressions of
10380 // constant expressions, but they can never be ICEs because an ICE cannot
10381 // contain an lvalue operand.
10382 return ICEDiag(IK_NotICE, E->getLocStart());
10401 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
10402 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
10403 if (Exp->getOpcode() == BO_Div ||
10404 Exp->getOpcode() == BO_Rem) {
10405 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
10406 // we don't evaluate one.
10407 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
10408 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
10410 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10411 if (REval.isSigned() && REval.isAllOnesValue()) {
10412 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
10413 if (LEval.isMinSignedValue())
10414 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10418 if (Exp->getOpcode() == BO_Comma) {
10419 if (Ctx.getLangOpts().C99) {
10420 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
10421 // if it isn't evaluated.
10422 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
10423 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10425 // In both C89 and C++, commas in ICEs are illegal.
10426 return ICEDiag(IK_NotICE, E->getLocStart());
10429 return Worst(LHSResult, RHSResult);
10433 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
10434 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
10435 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
10436 // Rare case where the RHS has a comma "side-effect"; we need
10437 // to actually check the condition to see whether the side
10438 // with the comma is evaluated.
10439 if ((Exp->getOpcode() == BO_LAnd) !=
10440 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
10445 return Worst(LHSResult, RHSResult);
10449 case Expr::ImplicitCastExprClass:
10450 case Expr::CStyleCastExprClass:
10451 case Expr::CXXFunctionalCastExprClass:
10452 case Expr::CXXStaticCastExprClass:
10453 case Expr::CXXReinterpretCastExprClass:
10454 case Expr::CXXConstCastExprClass:
10455 case Expr::ObjCBridgedCastExprClass: {
10456 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
10457 if (isa<ExplicitCastExpr>(E)) {
10458 if (const FloatingLiteral *FL
10459 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
10460 unsigned DestWidth = Ctx.getIntWidth(E->getType());
10461 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
10462 APSInt IgnoredVal(DestWidth, !DestSigned);
10464 // If the value does not fit in the destination type, the behavior is
10465 // undefined, so we are not required to treat it as a constant
10467 if (FL->getValue().convertToInteger(IgnoredVal,
10468 llvm::APFloat::rmTowardZero,
10469 &Ignored) & APFloat::opInvalidOp)
10470 return ICEDiag(IK_NotICE, E->getLocStart());
10474 switch (cast<CastExpr>(E)->getCastKind()) {
10475 case CK_LValueToRValue:
10476 case CK_AtomicToNonAtomic:
10477 case CK_NonAtomicToAtomic:
10479 case CK_IntegralToBoolean:
10480 case CK_IntegralCast:
10481 return CheckICE(SubExpr, Ctx);
10483 return ICEDiag(IK_NotICE, E->getLocStart());
10486 case Expr::BinaryConditionalOperatorClass: {
10487 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
10488 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
10489 if (CommonResult.Kind == IK_NotICE) return CommonResult;
10490 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
10491 if (FalseResult.Kind == IK_NotICE) return FalseResult;
10492 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
10493 if (FalseResult.Kind == IK_ICEIfUnevaluated &&
10494 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
10495 return FalseResult;
10497 case Expr::ConditionalOperatorClass: {
10498 const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
10499 // If the condition (ignoring parens) is a __builtin_constant_p call,
10500 // then only the true side is actually considered in an integer constant
10501 // expression, and it is fully evaluated. This is an important GNU
10502 // extension. See GCC PR38377 for discussion.
10503 if (const CallExpr *CallCE
10504 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
10505 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
10506 return CheckEvalInICE(E, Ctx);
10507 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
10508 if (CondResult.Kind == IK_NotICE)
10511 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
10512 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
10514 if (TrueResult.Kind == IK_NotICE)
10516 if (FalseResult.Kind == IK_NotICE)
10517 return FalseResult;
10518 if (CondResult.Kind == IK_ICEIfUnevaluated)
10520 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
10522 // Rare case where the diagnostics depend on which side is evaluated
10523 // Note that if we get here, CondResult is 0, and at least one of
10524 // TrueResult and FalseResult is non-zero.
10525 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
10526 return FalseResult;
10529 case Expr::CXXDefaultArgExprClass:
10530 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
10531 case Expr::CXXDefaultInitExprClass:
10532 return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx);
10533 case Expr::ChooseExprClass: {
10534 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
10538 llvm_unreachable("Invalid StmtClass!");
10541 /// Evaluate an expression as a C++11 integral constant expression.
10542 static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
10544 llvm::APSInt *Value,
10545 SourceLocation *Loc) {
10546 if (!E->getType()->isIntegralOrEnumerationType()) {
10547 if (Loc) *Loc = E->getExprLoc();
10552 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc))
10555 if (!Result.isInt()) {
10556 if (Loc) *Loc = E->getExprLoc();
10560 if (Value) *Value = Result.getInt();
10564 bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
10565 SourceLocation *Loc) const {
10566 if (Ctx.getLangOpts().CPlusPlus11)
10567 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc);
10569 ICEDiag D = CheckICE(this, Ctx);
10570 if (D.Kind != IK_ICE) {
10571 if (Loc) *Loc = D.Loc;
10577 bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, const ASTContext &Ctx,
10578 SourceLocation *Loc, bool isEvaluated) const {
10579 if (Ctx.getLangOpts().CPlusPlus11)
10580 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc);
10582 if (!isIntegerConstantExpr(Ctx, Loc))
10584 // The only possible side-effects here are due to UB discovered in the
10585 // evaluation (for instance, INT_MAX + 1). In such a case, we are still
10586 // required to treat the expression as an ICE, so we produce the folded
10588 if (!EvaluateAsInt(Value, Ctx, SE_AllowSideEffects))
10589 llvm_unreachable("ICE cannot be evaluated!");
10593 bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
10594 return CheckICE(this, Ctx).Kind == IK_ICE;
10597 bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
10598 SourceLocation *Loc) const {
10599 // We support this checking in C++98 mode in order to diagnose compatibility
10601 assert(Ctx.getLangOpts().CPlusPlus);
10603 // Build evaluation settings.
10604 Expr::EvalStatus Status;
10605 SmallVector<PartialDiagnosticAt, 8> Diags;
10606 Status.Diag = &Diags;
10607 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
10610 bool IsConstExpr = ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch);
10612 if (!Diags.empty()) {
10613 IsConstExpr = false;
10614 if (Loc) *Loc = Diags[0].first;
10615 } else if (!IsConstExpr) {
10616 // FIXME: This shouldn't happen.
10617 if (Loc) *Loc = getExprLoc();
10620 return IsConstExpr;
10623 bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
10624 const FunctionDecl *Callee,
10625 ArrayRef<const Expr*> Args,
10626 const Expr *This) const {
10627 Expr::EvalStatus Status;
10628 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
10631 const LValue *ThisPtr = nullptr;
10634 auto *MD = dyn_cast<CXXMethodDecl>(Callee);
10635 assert(MD && "Don't provide `this` for non-methods.");
10636 assert(!MD->isStatic() && "Don't provide `this` for static methods.");
10638 if (EvaluateObjectArgument(Info, This, ThisVal))
10639 ThisPtr = &ThisVal;
10640 if (Info.EvalStatus.HasSideEffects)
10644 ArgVector ArgValues(Args.size());
10645 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
10647 if ((*I)->isValueDependent() ||
10648 !Evaluate(ArgValues[I - Args.begin()], Info, *I))
10649 // If evaluation fails, throw away the argument entirely.
10650 ArgValues[I - Args.begin()] = APValue();
10651 if (Info.EvalStatus.HasSideEffects)
10655 // Build fake call to Callee.
10656 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr,
10658 return Evaluate(Value, Info, this) && !Info.EvalStatus.HasSideEffects;
10661 bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
10663 PartialDiagnosticAt> &Diags) {
10664 // FIXME: It would be useful to check constexpr function templates, but at the
10665 // moment the constant expression evaluator cannot cope with the non-rigorous
10666 // ASTs which we build for dependent expressions.
10667 if (FD->isDependentContext())
10670 Expr::EvalStatus Status;
10671 Status.Diag = &Diags;
10673 EvalInfo Info(FD->getASTContext(), Status,
10674 EvalInfo::EM_PotentialConstantExpression);
10676 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
10677 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;
10679 // Fabricate an arbitrary expression on the stack and pretend that it
10680 // is a temporary being used as the 'this' pointer.
10682 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
10683 This.set(&VIE, Info.CurrentCall->Index);
10685 ArrayRef<const Expr*> Args;
10688 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
10689 // Evaluate the call as a constant initializer, to allow the construction
10690 // of objects of non-literal types.
10691 Info.setEvaluatingDecl(This.getLValueBase(), Scratch);
10692 HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch);
10694 SourceLocation Loc = FD->getLocation();
10695 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : nullptr,
10696 Args, FD->getBody(), Info, Scratch, nullptr);
10699 return Diags.empty();
10702 bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
10703 const FunctionDecl *FD,
10705 PartialDiagnosticAt> &Diags) {
10706 Expr::EvalStatus Status;
10707 Status.Diag = &Diags;
10709 EvalInfo Info(FD->getASTContext(), Status,
10710 EvalInfo::EM_PotentialConstantExpressionUnevaluated);
10712 // Fabricate a call stack frame to give the arguments a plausible cover story.
10713 ArrayRef<const Expr*> Args;
10714 ArgVector ArgValues(0);
10715 bool Success = EvaluateArgs(Args, ArgValues, Info);
10718 "Failed to set up arguments for potential constant evaluation");
10719 CallStackFrame Frame(Info, SourceLocation(), FD, nullptr, ArgValues.data());
10721 APValue ResultScratch;
10722 Evaluate(ResultScratch, Info, E);
10723 return Diags.empty();
10726 bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
10727 unsigned Type) const {
10728 if (!getType()->isPointerType())
10731 Expr::EvalStatus Status;
10732 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
10733 return tryEvaluateBuiltinObjectSize(this, Type, Info, Result);