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, uint64_t N);
354 /// Add N to the address of this subobject.
355 void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) {
357 if (isMostDerivedAnUnsizedArray()) {
358 // Can't verify -- trust that the user is doing the right thing (or if
359 // not, trust that the caller will catch the bad behavior).
360 Entries.back().ArrayIndex += N;
363 if (MostDerivedPathLength == Entries.size() &&
364 MostDerivedIsArrayElement) {
365 Entries.back().ArrayIndex += N;
366 if (Entries.back().ArrayIndex > getMostDerivedArraySize()) {
367 diagnosePointerArithmetic(Info, E, Entries.back().ArrayIndex);
372 // [expr.add]p4: For the purposes of these operators, a pointer to a
373 // nonarray object behaves the same as a pointer to the first element of
374 // an array of length one with the type of the object as its element type.
375 if (IsOnePastTheEnd && N == (uint64_t)-1)
376 IsOnePastTheEnd = false;
377 else if (!IsOnePastTheEnd && N == 1)
378 IsOnePastTheEnd = true;
380 diagnosePointerArithmetic(Info, E, uint64_t(IsOnePastTheEnd) + N);
386 /// A stack frame in the constexpr call stack.
387 struct CallStackFrame {
390 /// Parent - The caller of this stack frame.
391 CallStackFrame *Caller;
393 /// Callee - The function which was called.
394 const FunctionDecl *Callee;
396 /// This - The binding for the this pointer in this call, if any.
399 /// Arguments - Parameter bindings for this function call, indexed by
400 /// parameters' function scope indices.
403 // Note that we intentionally use std::map here so that references to
404 // values are stable.
405 typedef std::map<const void*, APValue> MapTy;
406 typedef MapTy::const_iterator temp_iterator;
407 /// Temporaries - Temporary lvalues materialized within this stack frame.
410 /// CallLoc - The location of the call expression for this call.
411 SourceLocation CallLoc;
413 /// Index - The call index of this call.
416 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
417 const FunctionDecl *Callee, const LValue *This,
421 APValue *getTemporary(const void *Key) {
422 MapTy::iterator I = Temporaries.find(Key);
423 return I == Temporaries.end() ? nullptr : &I->second;
425 APValue &createTemporary(const void *Key, bool IsLifetimeExtended);
428 /// Temporarily override 'this'.
429 class ThisOverrideRAII {
431 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
432 : Frame(Frame), OldThis(Frame.This) {
434 Frame.This = NewThis;
436 ~ThisOverrideRAII() {
437 Frame.This = OldThis;
440 CallStackFrame &Frame;
441 const LValue *OldThis;
444 /// A partial diagnostic which we might know in advance that we are not going
446 class OptionalDiagnostic {
447 PartialDiagnostic *Diag;
450 explicit OptionalDiagnostic(PartialDiagnostic *Diag = nullptr)
454 OptionalDiagnostic &operator<<(const T &v) {
460 OptionalDiagnostic &operator<<(const APSInt &I) {
462 SmallVector<char, 32> Buffer;
464 *Diag << StringRef(Buffer.data(), Buffer.size());
469 OptionalDiagnostic &operator<<(const APFloat &F) {
471 // FIXME: Force the precision of the source value down so we don't
472 // print digits which are usually useless (we don't really care here if
473 // we truncate a digit by accident in edge cases). Ideally,
474 // APFloat::toString would automatically print the shortest
475 // representation which rounds to the correct value, but it's a bit
476 // tricky to implement.
478 llvm::APFloat::semanticsPrecision(F.getSemantics());
479 precision = (precision * 59 + 195) / 196;
480 SmallVector<char, 32> Buffer;
481 F.toString(Buffer, precision);
482 *Diag << StringRef(Buffer.data(), Buffer.size());
488 /// A cleanup, and a flag indicating whether it is lifetime-extended.
490 llvm::PointerIntPair<APValue*, 1, bool> Value;
493 Cleanup(APValue *Val, bool IsLifetimeExtended)
494 : Value(Val, IsLifetimeExtended) {}
496 bool isLifetimeExtended() const { return Value.getInt(); }
498 *Value.getPointer() = APValue();
502 /// EvalInfo - This is a private struct used by the evaluator to capture
503 /// information about a subexpression as it is folded. It retains information
504 /// about the AST context, but also maintains information about the folded
507 /// If an expression could be evaluated, it is still possible it is not a C
508 /// "integer constant expression" or constant expression. If not, this struct
509 /// captures information about how and why not.
511 /// One bit of information passed *into* the request for constant folding
512 /// indicates whether the subexpression is "evaluated" or not according to C
513 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
514 /// evaluate the expression regardless of what the RHS is, but C only allows
515 /// certain things in certain situations.
516 struct LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) EvalInfo {
519 /// EvalStatus - Contains information about the evaluation.
520 Expr::EvalStatus &EvalStatus;
522 /// CurrentCall - The top of the constexpr call stack.
523 CallStackFrame *CurrentCall;
525 /// CallStackDepth - The number of calls in the call stack right now.
526 unsigned CallStackDepth;
528 /// NextCallIndex - The next call index to assign.
529 unsigned NextCallIndex;
531 /// StepsLeft - The remaining number of evaluation steps we're permitted
532 /// to perform. This is essentially a limit for the number of statements
533 /// we will evaluate.
536 /// BottomFrame - The frame in which evaluation started. This must be
537 /// initialized after CurrentCall and CallStackDepth.
538 CallStackFrame BottomFrame;
540 /// A stack of values whose lifetimes end at the end of some surrounding
541 /// evaluation frame.
542 llvm::SmallVector<Cleanup, 16> CleanupStack;
544 /// EvaluatingDecl - This is the declaration whose initializer is being
545 /// evaluated, if any.
546 APValue::LValueBase EvaluatingDecl;
548 /// EvaluatingDeclValue - This is the value being constructed for the
549 /// declaration whose initializer is being evaluated, if any.
550 APValue *EvaluatingDeclValue;
552 /// The current array initialization index, if we're performing array
554 uint64_t ArrayInitIndex = -1;
556 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
557 /// notes attached to it will also be stored, otherwise they will not be.
558 bool HasActiveDiagnostic;
560 /// \brief Have we emitted a diagnostic explaining why we couldn't constant
561 /// fold (not just why it's not strictly a constant expression)?
562 bool HasFoldFailureDiagnostic;
564 /// \brief Whether or not we're currently speculatively evaluating.
565 bool IsSpeculativelyEvaluating;
567 enum EvaluationMode {
568 /// Evaluate as a constant expression. Stop if we find that the expression
569 /// is not a constant expression.
570 EM_ConstantExpression,
572 /// Evaluate as a potential constant expression. Keep going if we hit a
573 /// construct that we can't evaluate yet (because we don't yet know the
574 /// value of something) but stop if we hit something that could never be
575 /// a constant expression.
576 EM_PotentialConstantExpression,
578 /// Fold the expression to a constant. Stop if we hit a side-effect that
582 /// Evaluate the expression looking for integer overflow and similar
583 /// issues. Don't worry about side-effects, and try to visit all
585 EM_EvaluateForOverflow,
587 /// Evaluate in any way we know how. Don't worry about side-effects that
588 /// can't be modeled.
589 EM_IgnoreSideEffects,
591 /// Evaluate as a constant expression. Stop if we find that the expression
592 /// is not a constant expression. Some expressions can be retried in the
593 /// optimizer if we don't constant fold them here, but in an unevaluated
594 /// context we try to fold them immediately since the optimizer never
595 /// gets a chance to look at it.
596 EM_ConstantExpressionUnevaluated,
598 /// Evaluate as a potential constant expression. Keep going if we hit a
599 /// construct that we can't evaluate yet (because we don't yet know the
600 /// value of something) but stop if we hit something that could never be
601 /// a constant expression. Some expressions can be retried in the
602 /// optimizer if we don't constant fold them here, but in an unevaluated
603 /// context we try to fold them immediately since the optimizer never
604 /// gets a chance to look at it.
605 EM_PotentialConstantExpressionUnevaluated,
607 /// Evaluate as a constant expression. Continue evaluating if either:
608 /// - We find a MemberExpr with a base that can't be evaluated.
609 /// - We find a variable initialized with a call to a function that has
610 /// the alloc_size attribute on it.
611 /// In either case, the LValue returned shall have an invalid base; in the
612 /// former, the base will be the invalid MemberExpr, in the latter, the
613 /// base will be either the alloc_size CallExpr or a CastExpr wrapping
618 /// Are we checking whether the expression is a potential constant
620 bool checkingPotentialConstantExpression() const {
621 return EvalMode == EM_PotentialConstantExpression ||
622 EvalMode == EM_PotentialConstantExpressionUnevaluated;
625 /// Are we checking an expression for overflow?
626 // FIXME: We should check for any kind of undefined or suspicious behavior
627 // in such constructs, not just overflow.
628 bool checkingForOverflow() { return EvalMode == EM_EvaluateForOverflow; }
630 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
631 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
632 CallStackDepth(0), NextCallIndex(1),
633 StepsLeft(getLangOpts().ConstexprStepLimit),
634 BottomFrame(*this, SourceLocation(), nullptr, nullptr, nullptr),
635 EvaluatingDecl((const ValueDecl *)nullptr),
636 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
637 HasFoldFailureDiagnostic(false), IsSpeculativelyEvaluating(false),
640 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value) {
641 EvaluatingDecl = Base;
642 EvaluatingDeclValue = &Value;
645 const LangOptions &getLangOpts() const { return Ctx.getLangOpts(); }
647 bool CheckCallLimit(SourceLocation Loc) {
648 // Don't perform any constexpr calls (other than the call we're checking)
649 // when checking a potential constant expression.
650 if (checkingPotentialConstantExpression() && CallStackDepth > 1)
652 if (NextCallIndex == 0) {
653 // NextCallIndex has wrapped around.
654 FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
657 if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
659 FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded)
660 << getLangOpts().ConstexprCallDepth;
664 CallStackFrame *getCallFrame(unsigned CallIndex) {
665 assert(CallIndex && "no call index in getCallFrame");
666 // We will eventually hit BottomFrame, which has Index 1, so Frame can't
667 // be null in this loop.
668 CallStackFrame *Frame = CurrentCall;
669 while (Frame->Index > CallIndex)
670 Frame = Frame->Caller;
671 return (Frame->Index == CallIndex) ? Frame : nullptr;
674 bool nextStep(const Stmt *S) {
676 FFDiag(S->getLocStart(), diag::note_constexpr_step_limit_exceeded);
684 /// Add a diagnostic to the diagnostics list.
685 PartialDiagnostic &addDiag(SourceLocation Loc, diag::kind DiagId) {
686 PartialDiagnostic PD(DiagId, Ctx.getDiagAllocator());
687 EvalStatus.Diag->push_back(std::make_pair(Loc, PD));
688 return EvalStatus.Diag->back().second;
691 /// Add notes containing a call stack to the current point of evaluation.
692 void addCallStack(unsigned Limit);
695 OptionalDiagnostic Diag(SourceLocation Loc, diag::kind DiagId,
696 unsigned ExtraNotes, bool IsCCEDiag) {
698 if (EvalStatus.Diag) {
699 // If we have a prior diagnostic, it will be noting that the expression
700 // isn't a constant expression. This diagnostic is more important,
701 // unless we require this evaluation to produce a constant expression.
703 // FIXME: We might want to show both diagnostics to the user in
704 // EM_ConstantFold mode.
705 if (!EvalStatus.Diag->empty()) {
707 case EM_ConstantFold:
708 case EM_IgnoreSideEffects:
709 case EM_EvaluateForOverflow:
710 if (!HasFoldFailureDiagnostic)
712 // We've already failed to fold something. Keep that diagnostic.
713 case EM_ConstantExpression:
714 case EM_PotentialConstantExpression:
715 case EM_ConstantExpressionUnevaluated:
716 case EM_PotentialConstantExpressionUnevaluated:
718 HasActiveDiagnostic = false;
719 return OptionalDiagnostic();
723 unsigned CallStackNotes = CallStackDepth - 1;
724 unsigned Limit = Ctx.getDiagnostics().getConstexprBacktraceLimit();
726 CallStackNotes = std::min(CallStackNotes, Limit + 1);
727 if (checkingPotentialConstantExpression())
730 HasActiveDiagnostic = true;
731 HasFoldFailureDiagnostic = !IsCCEDiag;
732 EvalStatus.Diag->clear();
733 EvalStatus.Diag->reserve(1 + ExtraNotes + CallStackNotes);
734 addDiag(Loc, DiagId);
735 if (!checkingPotentialConstantExpression())
737 return OptionalDiagnostic(&(*EvalStatus.Diag)[0].second);
739 HasActiveDiagnostic = false;
740 return OptionalDiagnostic();
743 // Diagnose that the evaluation could not be folded (FF => FoldFailure)
745 FFDiag(SourceLocation Loc,
746 diag::kind DiagId = diag::note_invalid_subexpr_in_const_expr,
747 unsigned ExtraNotes = 0) {
748 return Diag(Loc, DiagId, ExtraNotes, false);
751 OptionalDiagnostic FFDiag(const Expr *E, diag::kind DiagId
752 = diag::note_invalid_subexpr_in_const_expr,
753 unsigned ExtraNotes = 0) {
755 return Diag(E->getExprLoc(), DiagId, ExtraNotes, /*IsCCEDiag*/false);
756 HasActiveDiagnostic = false;
757 return OptionalDiagnostic();
760 /// Diagnose that the evaluation does not produce a C++11 core constant
763 /// FIXME: Stop evaluating if we're in EM_ConstantExpression or
764 /// EM_PotentialConstantExpression mode and we produce one of these.
765 OptionalDiagnostic CCEDiag(SourceLocation Loc, diag::kind DiagId
766 = diag::note_invalid_subexpr_in_const_expr,
767 unsigned ExtraNotes = 0) {
768 // Don't override a previous diagnostic. Don't bother collecting
769 // diagnostics if we're evaluating for overflow.
770 if (!EvalStatus.Diag || !EvalStatus.Diag->empty()) {
771 HasActiveDiagnostic = false;
772 return OptionalDiagnostic();
774 return Diag(Loc, DiagId, ExtraNotes, true);
776 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind DiagId
777 = diag::note_invalid_subexpr_in_const_expr,
778 unsigned ExtraNotes = 0) {
779 return CCEDiag(E->getExprLoc(), DiagId, ExtraNotes);
781 /// Add a note to a prior diagnostic.
782 OptionalDiagnostic Note(SourceLocation Loc, diag::kind DiagId) {
783 if (!HasActiveDiagnostic)
784 return OptionalDiagnostic();
785 return OptionalDiagnostic(&addDiag(Loc, DiagId));
788 /// Add a stack of notes to a prior diagnostic.
789 void addNotes(ArrayRef<PartialDiagnosticAt> Diags) {
790 if (HasActiveDiagnostic) {
791 EvalStatus.Diag->insert(EvalStatus.Diag->end(),
792 Diags.begin(), Diags.end());
796 /// Should we continue evaluation after encountering a side-effect that we
798 bool keepEvaluatingAfterSideEffect() {
800 case EM_PotentialConstantExpression:
801 case EM_PotentialConstantExpressionUnevaluated:
802 case EM_EvaluateForOverflow:
803 case EM_IgnoreSideEffects:
806 case EM_ConstantExpression:
807 case EM_ConstantExpressionUnevaluated:
808 case EM_ConstantFold:
812 llvm_unreachable("Missed EvalMode case");
815 /// Note that we have had a side-effect, and determine whether we should
817 bool noteSideEffect() {
818 EvalStatus.HasSideEffects = true;
819 return keepEvaluatingAfterSideEffect();
822 /// Should we continue evaluation after encountering undefined behavior?
823 bool keepEvaluatingAfterUndefinedBehavior() {
825 case EM_EvaluateForOverflow:
826 case EM_IgnoreSideEffects:
827 case EM_ConstantFold:
831 case EM_PotentialConstantExpression:
832 case EM_PotentialConstantExpressionUnevaluated:
833 case EM_ConstantExpression:
834 case EM_ConstantExpressionUnevaluated:
837 llvm_unreachable("Missed EvalMode case");
840 /// Note that we hit something that was technically undefined behavior, but
841 /// that we can evaluate past it (such as signed overflow or floating-point
842 /// division by zero.)
843 bool noteUndefinedBehavior() {
844 EvalStatus.HasUndefinedBehavior = true;
845 return keepEvaluatingAfterUndefinedBehavior();
848 /// Should we continue evaluation as much as possible after encountering a
849 /// construct which can't be reduced to a value?
850 bool keepEvaluatingAfterFailure() {
855 case EM_PotentialConstantExpression:
856 case EM_PotentialConstantExpressionUnevaluated:
857 case EM_EvaluateForOverflow:
860 case EM_ConstantExpression:
861 case EM_ConstantExpressionUnevaluated:
862 case EM_ConstantFold:
863 case EM_IgnoreSideEffects:
867 llvm_unreachable("Missed EvalMode case");
870 /// Notes that we failed to evaluate an expression that other expressions
871 /// directly depend on, and determine if we should keep evaluating. This
872 /// should only be called if we actually intend to keep evaluating.
874 /// Call noteSideEffect() instead if we may be able to ignore the value that
875 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
877 /// (Foo(), 1) // use noteSideEffect
878 /// (Foo() || true) // use noteSideEffect
879 /// Foo() + 1 // use noteFailure
880 LLVM_NODISCARD bool noteFailure() {
881 // Failure when evaluating some expression often means there is some
882 // subexpression whose evaluation was skipped. Therefore, (because we
883 // don't track whether we skipped an expression when unwinding after an
884 // evaluation failure) every evaluation failure that bubbles up from a
885 // subexpression implies that a side-effect has potentially happened. We
886 // skip setting the HasSideEffects flag to true until we decide to
887 // continue evaluating after that point, which happens here.
888 bool KeepGoing = keepEvaluatingAfterFailure();
889 EvalStatus.HasSideEffects |= KeepGoing;
893 bool allowInvalidBaseExpr() const {
894 return EvalMode == EM_OffsetFold;
897 class ArrayInitLoopIndex {
902 ArrayInitLoopIndex(EvalInfo &Info)
903 : Info(Info), OuterIndex(Info.ArrayInitIndex) {
904 Info.ArrayInitIndex = 0;
906 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
908 operator uint64_t&() { return Info.ArrayInitIndex; }
912 /// Object used to treat all foldable expressions as constant expressions.
913 struct FoldConstant {
916 bool HadNoPriorDiags;
917 EvalInfo::EvaluationMode OldMode;
919 explicit FoldConstant(EvalInfo &Info, bool Enabled)
922 HadNoPriorDiags(Info.EvalStatus.Diag &&
923 Info.EvalStatus.Diag->empty() &&
924 !Info.EvalStatus.HasSideEffects),
925 OldMode(Info.EvalMode) {
927 (Info.EvalMode == EvalInfo::EM_ConstantExpression ||
928 Info.EvalMode == EvalInfo::EM_ConstantExpressionUnevaluated))
929 Info.EvalMode = EvalInfo::EM_ConstantFold;
931 void keepDiagnostics() { Enabled = false; }
933 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
934 !Info.EvalStatus.HasSideEffects)
935 Info.EvalStatus.Diag->clear();
936 Info.EvalMode = OldMode;
940 /// RAII object used to treat the current evaluation as the correct pointer
941 /// offset fold for the current EvalMode
942 struct FoldOffsetRAII {
944 EvalInfo::EvaluationMode OldMode;
945 explicit FoldOffsetRAII(EvalInfo &Info)
946 : Info(Info), OldMode(Info.EvalMode) {
947 if (!Info.checkingPotentialConstantExpression())
948 Info.EvalMode = EvalInfo::EM_OffsetFold;
951 ~FoldOffsetRAII() { Info.EvalMode = OldMode; }
954 /// RAII object used to optionally suppress diagnostics and side-effects from
955 /// a speculative evaluation.
956 class SpeculativeEvaluationRAII {
957 /// Pair of EvalInfo, and a bit that stores whether or not we were
958 /// speculatively evaluating when we created this RAII.
959 llvm::PointerIntPair<EvalInfo *, 1, bool> InfoAndOldSpecEval;
960 Expr::EvalStatus Old;
962 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
963 InfoAndOldSpecEval = Other.InfoAndOldSpecEval;
965 Other.InfoAndOldSpecEval.setPointer(nullptr);
968 void maybeRestoreState() {
969 EvalInfo *Info = InfoAndOldSpecEval.getPointer();
973 Info->EvalStatus = Old;
974 Info->IsSpeculativelyEvaluating = InfoAndOldSpecEval.getInt();
978 SpeculativeEvaluationRAII() = default;
980 SpeculativeEvaluationRAII(
981 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
982 : InfoAndOldSpecEval(&Info, Info.IsSpeculativelyEvaluating),
983 Old(Info.EvalStatus) {
984 Info.EvalStatus.Diag = NewDiag;
985 Info.IsSpeculativelyEvaluating = true;
988 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
989 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
990 moveFromAndCancel(std::move(Other));
993 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
995 moveFromAndCancel(std::move(Other));
999 ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1002 /// RAII object wrapping a full-expression or block scope, and handling
1003 /// the ending of the lifetime of temporaries created within it.
1004 template<bool IsFullExpression>
1007 unsigned OldStackSize;
1009 ScopeRAII(EvalInfo &Info)
1010 : Info(Info), OldStackSize(Info.CleanupStack.size()) {}
1012 // Body moved to a static method to encourage the compiler to inline away
1013 // instances of this class.
1014 cleanup(Info, OldStackSize);
1017 static void cleanup(EvalInfo &Info, unsigned OldStackSize) {
1018 unsigned NewEnd = OldStackSize;
1019 for (unsigned I = OldStackSize, N = Info.CleanupStack.size();
1021 if (IsFullExpression && Info.CleanupStack[I].isLifetimeExtended()) {
1022 // Full-expression cleanup of a lifetime-extended temporary: nothing
1023 // to do, just move this cleanup to the right place in the stack.
1024 std::swap(Info.CleanupStack[I], Info.CleanupStack[NewEnd]);
1027 // End the lifetime of the object.
1028 Info.CleanupStack[I].endLifetime();
1031 Info.CleanupStack.erase(Info.CleanupStack.begin() + NewEnd,
1032 Info.CleanupStack.end());
1035 typedef ScopeRAII<false> BlockScopeRAII;
1036 typedef ScopeRAII<true> FullExpressionRAII;
1039 bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1040 CheckSubobjectKind CSK) {
1043 if (isOnePastTheEnd()) {
1044 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
1052 void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1053 const Expr *E, uint64_t N) {
1054 // If we're complaining, we must be able to statically determine the size of
1055 // the most derived array.
1056 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1057 Info.CCEDiag(E, diag::note_constexpr_array_index)
1058 << static_cast<int>(N) << /*array*/ 0
1059 << static_cast<unsigned>(getMostDerivedArraySize());
1061 Info.CCEDiag(E, diag::note_constexpr_array_index)
1062 << static_cast<int>(N) << /*non-array*/ 1;
1066 CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
1067 const FunctionDecl *Callee, const LValue *This,
1069 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1070 Arguments(Arguments), CallLoc(CallLoc), Index(Info.NextCallIndex++) {
1071 Info.CurrentCall = this;
1072 ++Info.CallStackDepth;
1075 CallStackFrame::~CallStackFrame() {
1076 assert(Info.CurrentCall == this && "calls retired out of order");
1077 --Info.CallStackDepth;
1078 Info.CurrentCall = Caller;
1081 APValue &CallStackFrame::createTemporary(const void *Key,
1082 bool IsLifetimeExtended) {
1083 APValue &Result = Temporaries[Key];
1084 assert(Result.isUninit() && "temporary created multiple times");
1085 Info.CleanupStack.push_back(Cleanup(&Result, IsLifetimeExtended));
1089 static void describeCall(CallStackFrame *Frame, raw_ostream &Out);
1091 void EvalInfo::addCallStack(unsigned Limit) {
1092 // Determine which calls to skip, if any.
1093 unsigned ActiveCalls = CallStackDepth - 1;
1094 unsigned SkipStart = ActiveCalls, SkipEnd = SkipStart;
1095 if (Limit && Limit < ActiveCalls) {
1096 SkipStart = Limit / 2 + Limit % 2;
1097 SkipEnd = ActiveCalls - Limit / 2;
1100 // Walk the call stack and add the diagnostics.
1101 unsigned CallIdx = 0;
1102 for (CallStackFrame *Frame = CurrentCall; Frame != &BottomFrame;
1103 Frame = Frame->Caller, ++CallIdx) {
1105 if (CallIdx >= SkipStart && CallIdx < SkipEnd) {
1106 if (CallIdx == SkipStart) {
1107 // Note that we're skipping calls.
1108 addDiag(Frame->CallLoc, diag::note_constexpr_calls_suppressed)
1109 << unsigned(ActiveCalls - Limit);
1114 // Use a different note for an inheriting constructor, because from the
1115 // user's perspective it's not really a function at all.
1116 if (auto *CD = dyn_cast_or_null<CXXConstructorDecl>(Frame->Callee)) {
1117 if (CD->isInheritingConstructor()) {
1118 addDiag(Frame->CallLoc, diag::note_constexpr_inherited_ctor_call_here)
1124 SmallVector<char, 128> Buffer;
1125 llvm::raw_svector_ostream Out(Buffer);
1126 describeCall(Frame, Out);
1127 addDiag(Frame->CallLoc, diag::note_constexpr_call_here) << Out.str();
1132 struct ComplexValue {
1137 APSInt IntReal, IntImag;
1138 APFloat FloatReal, FloatImag;
1140 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1142 void makeComplexFloat() { IsInt = false; }
1143 bool isComplexFloat() const { return !IsInt; }
1144 APFloat &getComplexFloatReal() { return FloatReal; }
1145 APFloat &getComplexFloatImag() { return FloatImag; }
1147 void makeComplexInt() { IsInt = true; }
1148 bool isComplexInt() const { return IsInt; }
1149 APSInt &getComplexIntReal() { return IntReal; }
1150 APSInt &getComplexIntImag() { return IntImag; }
1152 void moveInto(APValue &v) const {
1153 if (isComplexFloat())
1154 v = APValue(FloatReal, FloatImag);
1156 v = APValue(IntReal, IntImag);
1158 void setFrom(const APValue &v) {
1159 assert(v.isComplexFloat() || v.isComplexInt());
1160 if (v.isComplexFloat()) {
1162 FloatReal = v.getComplexFloatReal();
1163 FloatImag = v.getComplexFloatImag();
1166 IntReal = v.getComplexIntReal();
1167 IntImag = v.getComplexIntImag();
1173 APValue::LValueBase Base;
1175 unsigned InvalidBase : 1;
1176 unsigned CallIndex : 31;
1177 SubobjectDesignator Designator;
1180 const APValue::LValueBase getLValueBase() const { return Base; }
1181 CharUnits &getLValueOffset() { return Offset; }
1182 const CharUnits &getLValueOffset() const { return Offset; }
1183 unsigned getLValueCallIndex() const { return CallIndex; }
1184 SubobjectDesignator &getLValueDesignator() { return Designator; }
1185 const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1186 bool isNullPointer() const { return IsNullPtr;}
1188 void moveInto(APValue &V) const {
1189 if (Designator.Invalid)
1190 V = APValue(Base, Offset, APValue::NoLValuePath(), CallIndex,
1193 assert(!InvalidBase && "APValues can't handle invalid LValue bases");
1194 assert(!Designator.FirstEntryIsAnUnsizedArray &&
1195 "Unsized array with a valid base?");
1196 V = APValue(Base, Offset, Designator.Entries,
1197 Designator.IsOnePastTheEnd, CallIndex, IsNullPtr);
1200 void setFrom(ASTContext &Ctx, const APValue &V) {
1201 assert(V.isLValue() && "Setting LValue from a non-LValue?");
1202 Base = V.getLValueBase();
1203 Offset = V.getLValueOffset();
1204 InvalidBase = false;
1205 CallIndex = V.getLValueCallIndex();
1206 Designator = SubobjectDesignator(Ctx, V);
1207 IsNullPtr = V.isNullPointer();
1210 void set(APValue::LValueBase B, unsigned I = 0, bool BInvalid = false,
1211 bool IsNullPtr_ = false, uint64_t Offset_ = 0) {
1213 // We only allow a few types of invalid bases. Enforce that here.
1215 const auto *E = B.get<const Expr *>();
1216 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&
1217 "Unexpected type of invalid base");
1222 Offset = CharUnits::fromQuantity(Offset_);
1223 InvalidBase = BInvalid;
1225 Designator = SubobjectDesignator(getType(B));
1226 IsNullPtr = IsNullPtr_;
1229 void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1233 // Check that this LValue is not based on a null pointer. If it is, produce
1234 // a diagnostic and mark the designator as invalid.
1235 bool checkNullPointer(EvalInfo &Info, const Expr *E,
1236 CheckSubobjectKind CSK) {
1237 if (Designator.Invalid)
1240 Info.CCEDiag(E, diag::note_constexpr_null_subobject)
1242 Designator.setInvalid();
1248 // Check this LValue refers to an object. If not, set the designator to be
1249 // invalid and emit a diagnostic.
1250 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1251 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1252 Designator.checkSubobject(Info, E, CSK);
1255 void addDecl(EvalInfo &Info, const Expr *E,
1256 const Decl *D, bool Virtual = false) {
1257 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
1258 Designator.addDeclUnchecked(D, Virtual);
1260 void addUnsizedArray(EvalInfo &Info, QualType ElemTy) {
1261 assert(Designator.Entries.empty() && getType(Base)->isPointerType());
1262 assert(isBaseAnAllocSizeCall(Base) &&
1263 "Only alloc_size bases can have unsized arrays");
1264 Designator.FirstEntryIsAnUnsizedArray = true;
1265 Designator.addUnsizedArrayUnchecked(ElemTy);
1267 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1268 if (checkSubobject(Info, E, CSK_ArrayToPointer))
1269 Designator.addArrayUnchecked(CAT);
1271 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1272 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
1273 Designator.addComplexUnchecked(EltTy, Imag);
1275 void clearIsNullPointer() {
1278 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E, uint64_t Index,
1279 CharUnits ElementSize) {
1280 // Compute the new offset in the appropriate width.
1281 Offset += Index * ElementSize;
1282 if (Index && checkNullPointer(Info, E, CSK_ArrayIndex))
1283 Designator.adjustIndex(Info, E, Index);
1285 clearIsNullPointer();
1287 void adjustOffset(CharUnits N) {
1289 if (N.getQuantity())
1290 clearIsNullPointer();
1296 explicit MemberPtr(const ValueDecl *Decl) :
1297 DeclAndIsDerivedMember(Decl, false), Path() {}
1299 /// The member or (direct or indirect) field referred to by this member
1300 /// pointer, or 0 if this is a null member pointer.
1301 const ValueDecl *getDecl() const {
1302 return DeclAndIsDerivedMember.getPointer();
1304 /// Is this actually a member of some type derived from the relevant class?
1305 bool isDerivedMember() const {
1306 return DeclAndIsDerivedMember.getInt();
1308 /// Get the class which the declaration actually lives in.
1309 const CXXRecordDecl *getContainingRecord() const {
1310 return cast<CXXRecordDecl>(
1311 DeclAndIsDerivedMember.getPointer()->getDeclContext());
1314 void moveInto(APValue &V) const {
1315 V = APValue(getDecl(), isDerivedMember(), Path);
1317 void setFrom(const APValue &V) {
1318 assert(V.isMemberPointer());
1319 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1320 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1322 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
1323 Path.insert(Path.end(), P.begin(), P.end());
1326 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1327 /// whether the member is a member of some class derived from the class type
1328 /// of the member pointer.
1329 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1330 /// Path - The path of base/derived classes from the member declaration's
1331 /// class (exclusive) to the class type of the member pointer (inclusive).
1332 SmallVector<const CXXRecordDecl*, 4> Path;
1334 /// Perform a cast towards the class of the Decl (either up or down the
1336 bool castBack(const CXXRecordDecl *Class) {
1337 assert(!Path.empty());
1338 const CXXRecordDecl *Expected;
1339 if (Path.size() >= 2)
1340 Expected = Path[Path.size() - 2];
1342 Expected = getContainingRecord();
1343 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1344 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1345 // if B does not contain the original member and is not a base or
1346 // derived class of the class containing the original member, the result
1347 // of the cast is undefined.
1348 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1349 // (D::*). We consider that to be a language defect.
1355 /// Perform a base-to-derived member pointer cast.
1356 bool castToDerived(const CXXRecordDecl *Derived) {
1359 if (!isDerivedMember()) {
1360 Path.push_back(Derived);
1363 if (!castBack(Derived))
1366 DeclAndIsDerivedMember.setInt(false);
1369 /// Perform a derived-to-base member pointer cast.
1370 bool castToBase(const CXXRecordDecl *Base) {
1374 DeclAndIsDerivedMember.setInt(true);
1375 if (isDerivedMember()) {
1376 Path.push_back(Base);
1379 return castBack(Base);
1383 /// Compare two member pointers, which are assumed to be of the same type.
1384 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1385 if (!LHS.getDecl() || !RHS.getDecl())
1386 return !LHS.getDecl() && !RHS.getDecl();
1387 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1389 return LHS.Path == RHS.Path;
1393 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1394 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1395 const LValue &This, const Expr *E,
1396 bool AllowNonLiteralTypes = false);
1397 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info);
1398 static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info);
1399 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1401 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1402 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1403 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1405 static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1406 static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1407 static bool EvaluateAtomic(const Expr *E, APValue &Result, EvalInfo &Info);
1408 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1410 //===----------------------------------------------------------------------===//
1412 //===----------------------------------------------------------------------===//
1414 /// Produce a string describing the given constexpr call.
1415 static void describeCall(CallStackFrame *Frame, raw_ostream &Out) {
1416 unsigned ArgIndex = 0;
1417 bool IsMemberCall = isa<CXXMethodDecl>(Frame->Callee) &&
1418 !isa<CXXConstructorDecl>(Frame->Callee) &&
1419 cast<CXXMethodDecl>(Frame->Callee)->isInstance();
1422 Out << *Frame->Callee << '(';
1424 if (Frame->This && IsMemberCall) {
1426 Frame->This->moveInto(Val);
1427 Val.printPretty(Out, Frame->Info.Ctx,
1428 Frame->This->Designator.MostDerivedType);
1429 // FIXME: Add parens around Val if needed.
1430 Out << "->" << *Frame->Callee << '(';
1431 IsMemberCall = false;
1434 for (FunctionDecl::param_const_iterator I = Frame->Callee->param_begin(),
1435 E = Frame->Callee->param_end(); I != E; ++I, ++ArgIndex) {
1436 if (ArgIndex > (unsigned)IsMemberCall)
1439 const ParmVarDecl *Param = *I;
1440 const APValue &Arg = Frame->Arguments[ArgIndex];
1441 Arg.printPretty(Out, Frame->Info.Ctx, Param->getType());
1443 if (ArgIndex == 0 && IsMemberCall)
1444 Out << "->" << *Frame->Callee << '(';
1450 /// Evaluate an expression to see if it had side-effects, and discard its
1452 /// \return \c true if the caller should keep evaluating.
1453 static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
1455 if (!Evaluate(Scratch, Info, E))
1456 // We don't need the value, but we might have skipped a side effect here.
1457 return Info.noteSideEffect();
1461 /// Sign- or zero-extend a value to 64 bits. If it's already 64 bits, just
1462 /// return its existing value.
1463 static int64_t getExtValue(const APSInt &Value) {
1464 return Value.isSigned() ? Value.getSExtValue()
1465 : static_cast<int64_t>(Value.getZExtValue());
1468 /// Should this call expression be treated as a string literal?
1469 static bool IsStringLiteralCall(const CallExpr *E) {
1470 unsigned Builtin = E->getBuiltinCallee();
1471 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
1472 Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
1475 static bool IsGlobalLValue(APValue::LValueBase B) {
1476 // C++11 [expr.const]p3 An address constant expression is a prvalue core
1477 // constant expression of pointer type that evaluates to...
1479 // ... a null pointer value, or a prvalue core constant expression of type
1481 if (!B) return true;
1483 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
1484 // ... the address of an object with static storage duration,
1485 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
1486 return VD->hasGlobalStorage();
1487 // ... the address of a function,
1488 return isa<FunctionDecl>(D);
1491 const Expr *E = B.get<const Expr*>();
1492 switch (E->getStmtClass()) {
1495 case Expr::CompoundLiteralExprClass: {
1496 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
1497 return CLE->isFileScope() && CLE->isLValue();
1499 case Expr::MaterializeTemporaryExprClass:
1500 // A materialized temporary might have been lifetime-extended to static
1501 // storage duration.
1502 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
1503 // A string literal has static storage duration.
1504 case Expr::StringLiteralClass:
1505 case Expr::PredefinedExprClass:
1506 case Expr::ObjCStringLiteralClass:
1507 case Expr::ObjCEncodeExprClass:
1508 case Expr::CXXTypeidExprClass:
1509 case Expr::CXXUuidofExprClass:
1511 case Expr::CallExprClass:
1512 return IsStringLiteralCall(cast<CallExpr>(E));
1513 // For GCC compatibility, &&label has static storage duration.
1514 case Expr::AddrLabelExprClass:
1516 // A Block literal expression may be used as the initialization value for
1517 // Block variables at global or local static scope.
1518 case Expr::BlockExprClass:
1519 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
1520 case Expr::ImplicitValueInitExprClass:
1522 // We can never form an lvalue with an implicit value initialization as its
1523 // base through expression evaluation, so these only appear in one case: the
1524 // implicit variable declaration we invent when checking whether a constexpr
1525 // constructor can produce a constant expression. We must assume that such
1526 // an expression might be a global lvalue.
1531 static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
1532 assert(Base && "no location for a null lvalue");
1533 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1535 Info.Note(VD->getLocation(), diag::note_declared_at);
1537 Info.Note(Base.get<const Expr*>()->getExprLoc(),
1538 diag::note_constexpr_temporary_here);
1541 /// Check that this reference or pointer core constant expression is a valid
1542 /// value for an address or reference constant expression. Return true if we
1543 /// can fold this expression, whether or not it's a constant expression.
1544 static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
1545 QualType Type, const LValue &LVal) {
1546 bool IsReferenceType = Type->isReferenceType();
1548 APValue::LValueBase Base = LVal.getLValueBase();
1549 const SubobjectDesignator &Designator = LVal.getLValueDesignator();
1551 // Check that the object is a global. Note that the fake 'this' object we
1552 // manufacture when checking potential constant expressions is conservatively
1553 // assumed to be global here.
1554 if (!IsGlobalLValue(Base)) {
1555 if (Info.getLangOpts().CPlusPlus11) {
1556 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1557 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
1558 << IsReferenceType << !Designator.Entries.empty()
1560 NoteLValueLocation(Info, Base);
1564 // Don't allow references to temporaries to escape.
1567 assert((Info.checkingPotentialConstantExpression() ||
1568 LVal.getLValueCallIndex() == 0) &&
1569 "have call index for global lvalue");
1571 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
1572 if (const VarDecl *Var = dyn_cast<const VarDecl>(VD)) {
1573 // Check if this is a thread-local variable.
1574 if (Var->getTLSKind())
1577 // A dllimport variable never acts like a constant.
1578 if (Var->hasAttr<DLLImportAttr>())
1581 if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) {
1582 // __declspec(dllimport) must be handled very carefully:
1583 // We must never initialize an expression with the thunk in C++.
1584 // Doing otherwise would allow the same id-expression to yield
1585 // different addresses for the same function in different translation
1586 // units. However, this means that we must dynamically initialize the
1587 // expression with the contents of the import address table at runtime.
1589 // The C language has no notion of ODR; furthermore, it has no notion of
1590 // dynamic initialization. This means that we are permitted to
1591 // perform initialization with the address of the thunk.
1592 if (Info.getLangOpts().CPlusPlus && FD->hasAttr<DLLImportAttr>())
1597 // Allow address constant expressions to be past-the-end pointers. This is
1598 // an extension: the standard requires them to point to an object.
1599 if (!IsReferenceType)
1602 // A reference constant expression must refer to an object.
1604 // FIXME: diagnostic
1609 // Does this refer one past the end of some object?
1610 if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
1611 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
1612 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
1613 << !Designator.Entries.empty() << !!VD << VD;
1614 NoteLValueLocation(Info, Base);
1620 /// Check that this core constant expression is of literal type, and if not,
1621 /// produce an appropriate diagnostic.
1622 static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
1623 const LValue *This = nullptr) {
1624 if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx))
1627 // C++1y: A constant initializer for an object o [...] may also invoke
1628 // constexpr constructors for o and its subobjects even if those objects
1629 // are of non-literal class types.
1631 // C++11 missed this detail for aggregates, so classes like this:
1632 // struct foo_t { union { int i; volatile int j; } u; };
1633 // are not (obviously) initializable like so:
1634 // __attribute__((__require_constant_initialization__))
1635 // static const foo_t x = {{0}};
1636 // because "i" is a subobject with non-literal initialization (due to the
1637 // volatile member of the union). See:
1638 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
1639 // Therefore, we use the C++1y behavior.
1640 if (This && Info.EvaluatingDecl == This->getLValueBase())
1643 // Prvalue constant expressions must be of literal types.
1644 if (Info.getLangOpts().CPlusPlus11)
1645 Info.FFDiag(E, diag::note_constexpr_nonliteral)
1648 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1652 /// Check that this core constant expression value is a valid value for a
1653 /// constant expression. If not, report an appropriate diagnostic. Does not
1654 /// check that the expression is of literal type.
1655 static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
1656 QualType Type, const APValue &Value) {
1657 if (Value.isUninit()) {
1658 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
1663 // We allow _Atomic(T) to be initialized from anything that T can be
1664 // initialized from.
1665 if (const AtomicType *AT = Type->getAs<AtomicType>())
1666 Type = AT->getValueType();
1668 // Core issue 1454: For a literal constant expression of array or class type,
1669 // each subobject of its value shall have been initialized by a constant
1671 if (Value.isArray()) {
1672 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
1673 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
1674 if (!CheckConstantExpression(Info, DiagLoc, EltTy,
1675 Value.getArrayInitializedElt(I)))
1678 if (!Value.hasArrayFiller())
1680 return CheckConstantExpression(Info, DiagLoc, EltTy,
1681 Value.getArrayFiller());
1683 if (Value.isUnion() && Value.getUnionField()) {
1684 return CheckConstantExpression(Info, DiagLoc,
1685 Value.getUnionField()->getType(),
1686 Value.getUnionValue());
1688 if (Value.isStruct()) {
1689 RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
1690 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
1691 unsigned BaseIndex = 0;
1692 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
1693 End = CD->bases_end(); I != End; ++I, ++BaseIndex) {
1694 if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
1695 Value.getStructBase(BaseIndex)))
1699 for (const auto *I : RD->fields()) {
1700 if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
1701 Value.getStructField(I->getFieldIndex())))
1706 if (Value.isLValue()) {
1708 LVal.setFrom(Info.Ctx, Value);
1709 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal);
1712 // Everything else is fine.
1716 static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
1717 return LVal.Base.dyn_cast<const ValueDecl*>();
1720 static bool IsLiteralLValue(const LValue &Value) {
1721 if (Value.CallIndex)
1723 const Expr *E = Value.Base.dyn_cast<const Expr*>();
1724 return E && !isa<MaterializeTemporaryExpr>(E);
1727 static bool IsWeakLValue(const LValue &Value) {
1728 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1729 return Decl && Decl->isWeak();
1732 static bool isZeroSized(const LValue &Value) {
1733 const ValueDecl *Decl = GetLValueBaseDecl(Value);
1734 if (Decl && isa<VarDecl>(Decl)) {
1735 QualType Ty = Decl->getType();
1736 if (Ty->isArrayType())
1737 return Ty->isIncompleteType() ||
1738 Decl->getASTContext().getTypeSize(Ty) == 0;
1743 static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
1744 // A null base expression indicates a null pointer. These are always
1745 // evaluatable, and they are false unless the offset is zero.
1746 if (!Value.getLValueBase()) {
1747 Result = !Value.getLValueOffset().isZero();
1751 // We have a non-null base. These are generally known to be true, but if it's
1752 // a weak declaration it can be null at runtime.
1754 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
1755 return !Decl || !Decl->isWeak();
1758 static bool HandleConversionToBool(const APValue &Val, bool &Result) {
1759 switch (Val.getKind()) {
1760 case APValue::Uninitialized:
1763 Result = Val.getInt().getBoolValue();
1765 case APValue::Float:
1766 Result = !Val.getFloat().isZero();
1768 case APValue::ComplexInt:
1769 Result = Val.getComplexIntReal().getBoolValue() ||
1770 Val.getComplexIntImag().getBoolValue();
1772 case APValue::ComplexFloat:
1773 Result = !Val.getComplexFloatReal().isZero() ||
1774 !Val.getComplexFloatImag().isZero();
1776 case APValue::LValue:
1777 return EvalPointerValueAsBool(Val, Result);
1778 case APValue::MemberPointer:
1779 Result = Val.getMemberPointerDecl();
1781 case APValue::Vector:
1782 case APValue::Array:
1783 case APValue::Struct:
1784 case APValue::Union:
1785 case APValue::AddrLabelDiff:
1789 llvm_unreachable("unknown APValue kind");
1792 static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
1794 assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition");
1796 if (!Evaluate(Val, Info, E))
1798 return HandleConversionToBool(Val, Result);
1801 template<typename T>
1802 static bool HandleOverflow(EvalInfo &Info, const Expr *E,
1803 const T &SrcValue, QualType DestType) {
1804 Info.CCEDiag(E, diag::note_constexpr_overflow)
1805 << SrcValue << DestType;
1806 return Info.noteUndefinedBehavior();
1809 static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
1810 QualType SrcType, const APFloat &Value,
1811 QualType DestType, APSInt &Result) {
1812 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
1813 // Determine whether we are converting to unsigned or signed.
1814 bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
1816 Result = APSInt(DestWidth, !DestSigned);
1818 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
1819 & APFloat::opInvalidOp)
1820 return HandleOverflow(Info, E, Value, DestType);
1824 static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
1825 QualType SrcType, QualType DestType,
1827 APFloat Value = Result;
1829 if (Result.convert(Info.Ctx.getFloatTypeSemantics(DestType),
1830 APFloat::rmNearestTiesToEven, &ignored)
1831 & APFloat::opOverflow)
1832 return HandleOverflow(Info, E, Value, DestType);
1836 static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
1837 QualType DestType, QualType SrcType,
1838 const APSInt &Value) {
1839 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
1840 APSInt Result = Value;
1841 // Figure out if this is a truncate, extend or noop cast.
1842 // If the input is signed, do a sign extend, noop, or truncate.
1843 Result = Result.extOrTrunc(DestWidth);
1844 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
1848 static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
1849 QualType SrcType, const APSInt &Value,
1850 QualType DestType, APFloat &Result) {
1851 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
1852 if (Result.convertFromAPInt(Value, Value.isSigned(),
1853 APFloat::rmNearestTiesToEven)
1854 & APFloat::opOverflow)
1855 return HandleOverflow(Info, E, Value, DestType);
1859 static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
1860 APValue &Value, const FieldDecl *FD) {
1861 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield");
1863 if (!Value.isInt()) {
1864 // Trying to store a pointer-cast-to-integer into a bitfield.
1865 // FIXME: In this case, we should provide the diagnostic for casting
1866 // a pointer to an integer.
1867 assert(Value.isLValue() && "integral value neither int nor lvalue?");
1872 APSInt &Int = Value.getInt();
1873 unsigned OldBitWidth = Int.getBitWidth();
1874 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx);
1875 if (NewBitWidth < OldBitWidth)
1876 Int = Int.trunc(NewBitWidth).extend(OldBitWidth);
1880 static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
1883 if (!Evaluate(SVal, Info, E))
1886 Res = SVal.getInt();
1889 if (SVal.isFloat()) {
1890 Res = SVal.getFloat().bitcastToAPInt();
1893 if (SVal.isVector()) {
1894 QualType VecTy = E->getType();
1895 unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
1896 QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
1897 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
1898 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
1899 Res = llvm::APInt::getNullValue(VecSize);
1900 for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
1901 APValue &Elt = SVal.getVectorElt(i);
1902 llvm::APInt EltAsInt;
1904 EltAsInt = Elt.getInt();
1905 } else if (Elt.isFloat()) {
1906 EltAsInt = Elt.getFloat().bitcastToAPInt();
1908 // Don't try to handle vectors of anything other than int or float
1909 // (not sure if it's possible to hit this case).
1910 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1913 unsigned BaseEltSize = EltAsInt.getBitWidth();
1915 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
1917 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
1921 // Give up if the input isn't an int, float, or vector. For example, we
1922 // reject "(v4i16)(intptr_t)&a".
1923 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
1927 /// Perform the given integer operation, which is known to need at most BitWidth
1928 /// bits, and check for overflow in the original type (if that type was not an
1930 template<typename Operation>
1931 static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
1932 const APSInt &LHS, const APSInt &RHS,
1933 unsigned BitWidth, Operation Op,
1935 if (LHS.isUnsigned()) {
1936 Result = Op(LHS, RHS);
1940 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
1941 Result = Value.trunc(LHS.getBitWidth());
1942 if (Result.extend(BitWidth) != Value) {
1943 if (Info.checkingForOverflow())
1944 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
1945 diag::warn_integer_constant_overflow)
1946 << Result.toString(10) << E->getType();
1948 return HandleOverflow(Info, E, Value, E->getType());
1953 /// Perform the given binary integer operation.
1954 static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS,
1955 BinaryOperatorKind Opcode, APSInt RHS,
1962 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
1963 std::multiplies<APSInt>(), Result);
1965 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
1966 std::plus<APSInt>(), Result);
1968 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
1969 std::minus<APSInt>(), Result);
1970 case BO_And: Result = LHS & RHS; return true;
1971 case BO_Xor: Result = LHS ^ RHS; return true;
1972 case BO_Or: Result = LHS | RHS; return true;
1976 Info.FFDiag(E, diag::note_expr_divide_by_zero);
1979 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
1980 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
1981 // this operation and gives the two's complement result.
1982 if (RHS.isNegative() && RHS.isAllOnesValue() &&
1983 LHS.isSigned() && LHS.isMinSignedValue())
1984 return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1),
1988 if (Info.getLangOpts().OpenCL)
1989 // OpenCL 6.3j: shift values are effectively % word size of LHS.
1990 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
1991 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
1993 else if (RHS.isSigned() && RHS.isNegative()) {
1994 // During constant-folding, a negative shift is an opposite shift. Such
1995 // a shift is not a constant expression.
1996 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2001 // C++11 [expr.shift]p1: Shift width must be less than the bit width of
2002 // the shifted type.
2003 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2005 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2006 << RHS << E->getType() << LHS.getBitWidth();
2007 } else if (LHS.isSigned()) {
2008 // C++11 [expr.shift]p2: A signed left shift must have a non-negative
2009 // operand, and must not overflow the corresponding unsigned type.
2010 if (LHS.isNegative())
2011 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
2012 else if (LHS.countLeadingZeros() < SA)
2013 Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
2019 if (Info.getLangOpts().OpenCL)
2020 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2021 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2022 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2024 else if (RHS.isSigned() && RHS.isNegative()) {
2025 // During constant-folding, a negative shift is an opposite shift. Such a
2026 // shift is not a constant expression.
2027 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2032 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
2034 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2036 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2037 << RHS << E->getType() << LHS.getBitWidth();
2042 case BO_LT: Result = LHS < RHS; return true;
2043 case BO_GT: Result = LHS > RHS; return true;
2044 case BO_LE: Result = LHS <= RHS; return true;
2045 case BO_GE: Result = LHS >= RHS; return true;
2046 case BO_EQ: Result = LHS == RHS; return true;
2047 case BO_NE: Result = LHS != RHS; return true;
2051 /// Perform the given binary floating-point operation, in-place, on LHS.
2052 static bool handleFloatFloatBinOp(EvalInfo &Info, const Expr *E,
2053 APFloat &LHS, BinaryOperatorKind Opcode,
2054 const APFloat &RHS) {
2060 LHS.multiply(RHS, APFloat::rmNearestTiesToEven);
2063 LHS.add(RHS, APFloat::rmNearestTiesToEven);
2066 LHS.subtract(RHS, APFloat::rmNearestTiesToEven);
2069 LHS.divide(RHS, APFloat::rmNearestTiesToEven);
2073 if (LHS.isInfinity() || LHS.isNaN()) {
2074 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
2075 return Info.noteUndefinedBehavior();
2080 /// Cast an lvalue referring to a base subobject to a derived class, by
2081 /// truncating the lvalue's path to the given length.
2082 static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
2083 const RecordDecl *TruncatedType,
2084 unsigned TruncatedElements) {
2085 SubobjectDesignator &D = Result.Designator;
2087 // Check we actually point to a derived class object.
2088 if (TruncatedElements == D.Entries.size())
2090 assert(TruncatedElements >= D.MostDerivedPathLength &&
2091 "not casting to a derived class");
2092 if (!Result.checkSubobject(Info, E, CSK_Derived))
2095 // Truncate the path to the subobject, and remove any derived-to-base offsets.
2096 const RecordDecl *RD = TruncatedType;
2097 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
2098 if (RD->isInvalidDecl()) return false;
2099 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
2100 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
2101 if (isVirtualBaseClass(D.Entries[I]))
2102 Result.Offset -= Layout.getVBaseClassOffset(Base);
2104 Result.Offset -= Layout.getBaseClassOffset(Base);
2107 D.Entries.resize(TruncatedElements);
2111 static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2112 const CXXRecordDecl *Derived,
2113 const CXXRecordDecl *Base,
2114 const ASTRecordLayout *RL = nullptr) {
2116 if (Derived->isInvalidDecl()) return false;
2117 RL = &Info.Ctx.getASTRecordLayout(Derived);
2120 Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
2121 Obj.addDecl(Info, E, Base, /*Virtual*/ false);
2125 static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
2126 const CXXRecordDecl *DerivedDecl,
2127 const CXXBaseSpecifier *Base) {
2128 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
2130 if (!Base->isVirtual())
2131 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
2133 SubobjectDesignator &D = Obj.Designator;
2137 // Extract most-derived object and corresponding type.
2138 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
2139 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
2142 // Find the virtual base class.
2143 if (DerivedDecl->isInvalidDecl()) return false;
2144 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
2145 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
2146 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
2150 static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
2151 QualType Type, LValue &Result) {
2152 for (CastExpr::path_const_iterator PathI = E->path_begin(),
2153 PathE = E->path_end();
2154 PathI != PathE; ++PathI) {
2155 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
2158 Type = (*PathI)->getType();
2163 /// Update LVal to refer to the given field, which must be a member of the type
2164 /// currently described by LVal.
2165 static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
2166 const FieldDecl *FD,
2167 const ASTRecordLayout *RL = nullptr) {
2169 if (FD->getParent()->isInvalidDecl()) return false;
2170 RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
2173 unsigned I = FD->getFieldIndex();
2174 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)));
2175 LVal.addDecl(Info, E, FD);
2179 /// Update LVal to refer to the given indirect field.
2180 static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
2182 const IndirectFieldDecl *IFD) {
2183 for (const auto *C : IFD->chain())
2184 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C)))
2189 /// Get the size of the given type in char units.
2190 static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
2191 QualType Type, CharUnits &Size) {
2192 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
2194 if (Type->isVoidType() || Type->isFunctionType()) {
2195 Size = CharUnits::One();
2199 if (Type->isDependentType()) {
2204 if (!Type->isConstantSizeType()) {
2205 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
2206 // FIXME: Better diagnostic.
2211 Size = Info.Ctx.getTypeSizeInChars(Type);
2215 /// Update a pointer value to model pointer arithmetic.
2216 /// \param Info - Information about the ongoing evaluation.
2217 /// \param E - The expression being evaluated, for diagnostic purposes.
2218 /// \param LVal - The pointer value to be updated.
2219 /// \param EltTy - The pointee type represented by LVal.
2220 /// \param Adjustment - The adjustment, in objects of type EltTy, to add.
2221 static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
2222 LValue &LVal, QualType EltTy,
2223 int64_t Adjustment) {
2224 CharUnits SizeOfPointee;
2225 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
2228 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee);
2232 /// Update an lvalue to refer to a component of a complex number.
2233 /// \param Info - Information about the ongoing evaluation.
2234 /// \param LVal - The lvalue to be updated.
2235 /// \param EltTy - The complex number's component type.
2236 /// \param Imag - False for the real component, true for the imaginary.
2237 static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
2238 LValue &LVal, QualType EltTy,
2241 CharUnits SizeOfComponent;
2242 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
2244 LVal.Offset += SizeOfComponent;
2246 LVal.addComplex(Info, E, EltTy, Imag);
2250 /// Try to evaluate the initializer for a variable declaration.
2252 /// \param Info Information about the ongoing evaluation.
2253 /// \param E An expression to be used when printing diagnostics.
2254 /// \param VD The variable whose initializer should be obtained.
2255 /// \param Frame The frame in which the variable was created. Must be null
2256 /// if this variable is not local to the evaluation.
2257 /// \param Result Filled in with a pointer to the value of the variable.
2258 static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
2259 const VarDecl *VD, CallStackFrame *Frame,
2261 // If this is a parameter to an active constexpr function call, perform
2262 // argument substitution.
2263 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) {
2264 // Assume arguments of a potential constant expression are unknown
2265 // constant expressions.
2266 if (Info.checkingPotentialConstantExpression())
2268 if (!Frame || !Frame->Arguments) {
2269 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2272 Result = &Frame->Arguments[PVD->getFunctionScopeIndex()];
2276 // If this is a local variable, dig out its value.
2278 Result = Frame->getTemporary(VD);
2280 // Assume variables referenced within a lambda's call operator that were
2281 // not declared within the call operator are captures and during checking
2282 // of a potential constant expression, assume they are unknown constant
2284 assert(isLambdaCallOperator(Frame->Callee) &&
2285 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&
2286 "missing value for local variable");
2287 if (Info.checkingPotentialConstantExpression())
2289 // FIXME: implement capture evaluation during constant expr evaluation.
2290 Info.FFDiag(E->getLocStart(),
2291 diag::note_unimplemented_constexpr_lambda_feature_ast)
2292 << "captures not currently allowed";
2298 // Dig out the initializer, and use the declaration which it's attached to.
2299 const Expr *Init = VD->getAnyInitializer(VD);
2300 if (!Init || Init->isValueDependent()) {
2301 // If we're checking a potential constant expression, the variable could be
2302 // initialized later.
2303 if (!Info.checkingPotentialConstantExpression())
2304 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2308 // If we're currently evaluating the initializer of this declaration, use that
2310 if (Info.EvaluatingDecl.dyn_cast<const ValueDecl*>() == VD) {
2311 Result = Info.EvaluatingDeclValue;
2315 // Never evaluate the initializer of a weak variable. We can't be sure that
2316 // this is the definition which will be used.
2318 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2322 // Check that we can fold the initializer. In C++, we will have already done
2323 // this in the cases where it matters for conformance.
2324 SmallVector<PartialDiagnosticAt, 8> Notes;
2325 if (!VD->evaluateValue(Notes)) {
2326 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant,
2327 Notes.size() + 1) << VD;
2328 Info.Note(VD->getLocation(), diag::note_declared_at);
2329 Info.addNotes(Notes);
2331 } else if (!VD->checkInitIsICE()) {
2332 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant,
2333 Notes.size() + 1) << VD;
2334 Info.Note(VD->getLocation(), diag::note_declared_at);
2335 Info.addNotes(Notes);
2338 Result = VD->getEvaluatedValue();
2342 static bool IsConstNonVolatile(QualType T) {
2343 Qualifiers Quals = T.getQualifiers();
2344 return Quals.hasConst() && !Quals.hasVolatile();
2347 /// Get the base index of the given base class within an APValue representing
2348 /// the given derived class.
2349 static unsigned getBaseIndex(const CXXRecordDecl *Derived,
2350 const CXXRecordDecl *Base) {
2351 Base = Base->getCanonicalDecl();
2353 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
2354 E = Derived->bases_end(); I != E; ++I, ++Index) {
2355 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
2359 llvm_unreachable("base class missing from derived class's bases list");
2362 /// Extract the value of a character from a string literal.
2363 static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
2365 // FIXME: Support ObjCEncodeExpr, MakeStringConstant
2366 if (auto PE = dyn_cast<PredefinedExpr>(Lit))
2367 Lit = PE->getFunctionName();
2368 const StringLiteral *S = cast<StringLiteral>(Lit);
2369 const ConstantArrayType *CAT =
2370 Info.Ctx.getAsConstantArrayType(S->getType());
2371 assert(CAT && "string literal isn't an array");
2372 QualType CharType = CAT->getElementType();
2373 assert(CharType->isIntegerType() && "unexpected character type");
2375 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
2376 CharType->isUnsignedIntegerType());
2377 if (Index < S->getLength())
2378 Value = S->getCodeUnit(Index);
2382 // Expand a string literal into an array of characters.
2383 static void expandStringLiteral(EvalInfo &Info, const Expr *Lit,
2385 const StringLiteral *S = cast<StringLiteral>(Lit);
2386 const ConstantArrayType *CAT =
2387 Info.Ctx.getAsConstantArrayType(S->getType());
2388 assert(CAT && "string literal isn't an array");
2389 QualType CharType = CAT->getElementType();
2390 assert(CharType->isIntegerType() && "unexpected character type");
2392 unsigned Elts = CAT->getSize().getZExtValue();
2393 Result = APValue(APValue::UninitArray(),
2394 std::min(S->getLength(), Elts), Elts);
2395 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
2396 CharType->isUnsignedIntegerType());
2397 if (Result.hasArrayFiller())
2398 Result.getArrayFiller() = APValue(Value);
2399 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
2400 Value = S->getCodeUnit(I);
2401 Result.getArrayInitializedElt(I) = APValue(Value);
2405 // Expand an array so that it has more than Index filled elements.
2406 static void expandArray(APValue &Array, unsigned Index) {
2407 unsigned Size = Array.getArraySize();
2408 assert(Index < Size);
2410 // Always at least double the number of elements for which we store a value.
2411 unsigned OldElts = Array.getArrayInitializedElts();
2412 unsigned NewElts = std::max(Index+1, OldElts * 2);
2413 NewElts = std::min(Size, std::max(NewElts, 8u));
2415 // Copy the data across.
2416 APValue NewValue(APValue::UninitArray(), NewElts, Size);
2417 for (unsigned I = 0; I != OldElts; ++I)
2418 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I));
2419 for (unsigned I = OldElts; I != NewElts; ++I)
2420 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
2421 if (NewValue.hasArrayFiller())
2422 NewValue.getArrayFiller() = Array.getArrayFiller();
2423 Array.swap(NewValue);
2426 /// Determine whether a type would actually be read by an lvalue-to-rvalue
2427 /// conversion. If it's of class type, we may assume that the copy operation
2428 /// is trivial. Note that this is never true for a union type with fields
2429 /// (because the copy always "reads" the active member) and always true for
2430 /// a non-class type.
2431 static bool isReadByLvalueToRvalueConversion(QualType T) {
2432 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
2433 if (!RD || (RD->isUnion() && !RD->field_empty()))
2438 for (auto *Field : RD->fields())
2439 if (isReadByLvalueToRvalueConversion(Field->getType()))
2442 for (auto &BaseSpec : RD->bases())
2443 if (isReadByLvalueToRvalueConversion(BaseSpec.getType()))
2449 /// Diagnose an attempt to read from any unreadable field within the specified
2450 /// type, which might be a class type.
2451 static bool diagnoseUnreadableFields(EvalInfo &Info, const Expr *E,
2453 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
2457 if (!RD->hasMutableFields())
2460 for (auto *Field : RD->fields()) {
2461 // If we're actually going to read this field in some way, then it can't
2462 // be mutable. If we're in a union, then assigning to a mutable field
2463 // (even an empty one) can change the active member, so that's not OK.
2464 // FIXME: Add core issue number for the union case.
2465 if (Field->isMutable() &&
2466 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
2467 Info.FFDiag(E, diag::note_constexpr_ltor_mutable, 1) << Field;
2468 Info.Note(Field->getLocation(), diag::note_declared_at);
2472 if (diagnoseUnreadableFields(Info, E, Field->getType()))
2476 for (auto &BaseSpec : RD->bases())
2477 if (diagnoseUnreadableFields(Info, E, BaseSpec.getType()))
2480 // All mutable fields were empty, and thus not actually read.
2484 /// Kinds of access we can perform on an object, for diagnostics.
2493 /// A handle to a complete object (an object that is not a subobject of
2494 /// another object).
2495 struct CompleteObject {
2496 /// The value of the complete object.
2498 /// The type of the complete object.
2501 CompleteObject() : Value(nullptr) {}
2502 CompleteObject(APValue *Value, QualType Type)
2503 : Value(Value), Type(Type) {
2504 assert(Value && "missing value for complete object");
2507 explicit operator bool() const { return Value; }
2509 } // end anonymous namespace
2511 /// Find the designated sub-object of an rvalue.
2512 template<typename SubobjectHandler>
2513 typename SubobjectHandler::result_type
2514 findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
2515 const SubobjectDesignator &Sub, SubobjectHandler &handler) {
2517 // A diagnostic will have already been produced.
2518 return handler.failed();
2519 if (Sub.isOnePastTheEnd()) {
2520 if (Info.getLangOpts().CPlusPlus11)
2521 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2522 << handler.AccessKind;
2525 return handler.failed();
2528 APValue *O = Obj.Value;
2529 QualType ObjType = Obj.Type;
2530 const FieldDecl *LastField = nullptr;
2532 // Walk the designator's path to find the subobject.
2533 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
2534 if (O->isUninit()) {
2535 if (!Info.checkingPotentialConstantExpression())
2536 Info.FFDiag(E, diag::note_constexpr_access_uninit) << handler.AccessKind;
2537 return handler.failed();
2541 // If we are reading an object of class type, there may still be more
2542 // things we need to check: if there are any mutable subobjects, we
2543 // cannot perform this read. (This only happens when performing a trivial
2544 // copy or assignment.)
2545 if (ObjType->isRecordType() && handler.AccessKind == AK_Read &&
2546 diagnoseUnreadableFields(Info, E, ObjType))
2547 return handler.failed();
2549 if (!handler.found(*O, ObjType))
2552 // If we modified a bit-field, truncate it to the right width.
2553 if (handler.AccessKind != AK_Read &&
2554 LastField && LastField->isBitField() &&
2555 !truncateBitfieldValue(Info, E, *O, LastField))
2561 LastField = nullptr;
2562 if (ObjType->isArrayType()) {
2563 // Next subobject is an array element.
2564 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
2565 assert(CAT && "vla in literal type?");
2566 uint64_t Index = Sub.Entries[I].ArrayIndex;
2567 if (CAT->getSize().ule(Index)) {
2568 // Note, it should not be possible to form a pointer with a valid
2569 // designator which points more than one past the end of the array.
2570 if (Info.getLangOpts().CPlusPlus11)
2571 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2572 << handler.AccessKind;
2575 return handler.failed();
2578 ObjType = CAT->getElementType();
2580 // An array object is represented as either an Array APValue or as an
2581 // LValue which refers to a string literal.
2582 if (O->isLValue()) {
2583 assert(I == N - 1 && "extracting subobject of character?");
2584 assert(!O->hasLValuePath() || O->getLValuePath().empty());
2585 if (handler.AccessKind != AK_Read)
2586 expandStringLiteral(Info, O->getLValueBase().get<const Expr *>(),
2589 return handler.foundString(*O, ObjType, Index);
2592 if (O->getArrayInitializedElts() > Index)
2593 O = &O->getArrayInitializedElt(Index);
2594 else if (handler.AccessKind != AK_Read) {
2595 expandArray(*O, Index);
2596 O = &O->getArrayInitializedElt(Index);
2598 O = &O->getArrayFiller();
2599 } else if (ObjType->isAnyComplexType()) {
2600 // Next subobject is a complex number.
2601 uint64_t Index = Sub.Entries[I].ArrayIndex;
2603 if (Info.getLangOpts().CPlusPlus11)
2604 Info.FFDiag(E, diag::note_constexpr_access_past_end)
2605 << handler.AccessKind;
2608 return handler.failed();
2611 bool WasConstQualified = ObjType.isConstQualified();
2612 ObjType = ObjType->castAs<ComplexType>()->getElementType();
2613 if (WasConstQualified)
2616 assert(I == N - 1 && "extracting subobject of scalar?");
2617 if (O->isComplexInt()) {
2618 return handler.found(Index ? O->getComplexIntImag()
2619 : O->getComplexIntReal(), ObjType);
2621 assert(O->isComplexFloat());
2622 return handler.found(Index ? O->getComplexFloatImag()
2623 : O->getComplexFloatReal(), ObjType);
2625 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
2626 if (Field->isMutable() && handler.AccessKind == AK_Read) {
2627 Info.FFDiag(E, diag::note_constexpr_ltor_mutable, 1)
2629 Info.Note(Field->getLocation(), diag::note_declared_at);
2630 return handler.failed();
2633 // Next subobject is a class, struct or union field.
2634 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
2635 if (RD->isUnion()) {
2636 const FieldDecl *UnionField = O->getUnionField();
2638 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
2639 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
2640 << handler.AccessKind << Field << !UnionField << UnionField;
2641 return handler.failed();
2643 O = &O->getUnionValue();
2645 O = &O->getStructField(Field->getFieldIndex());
2647 bool WasConstQualified = ObjType.isConstQualified();
2648 ObjType = Field->getType();
2649 if (WasConstQualified && !Field->isMutable())
2652 if (ObjType.isVolatileQualified()) {
2653 if (Info.getLangOpts().CPlusPlus) {
2654 // FIXME: Include a description of the path to the volatile subobject.
2655 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
2656 << handler.AccessKind << 2 << Field;
2657 Info.Note(Field->getLocation(), diag::note_declared_at);
2659 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2661 return handler.failed();
2666 // Next subobject is a base class.
2667 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
2668 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
2669 O = &O->getStructBase(getBaseIndex(Derived, Base));
2671 bool WasConstQualified = ObjType.isConstQualified();
2672 ObjType = Info.Ctx.getRecordType(Base);
2673 if (WasConstQualified)
2680 struct ExtractSubobjectHandler {
2684 static const AccessKinds AccessKind = AK_Read;
2686 typedef bool result_type;
2687 bool failed() { return false; }
2688 bool found(APValue &Subobj, QualType SubobjType) {
2692 bool found(APSInt &Value, QualType SubobjType) {
2693 Result = APValue(Value);
2696 bool found(APFloat &Value, QualType SubobjType) {
2697 Result = APValue(Value);
2700 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
2701 Result = APValue(extractStringLiteralCharacter(
2702 Info, Subobj.getLValueBase().get<const Expr *>(), Character));
2706 } // end anonymous namespace
2708 const AccessKinds ExtractSubobjectHandler::AccessKind;
2710 /// Extract the designated sub-object of an rvalue.
2711 static bool extractSubobject(EvalInfo &Info, const Expr *E,
2712 const CompleteObject &Obj,
2713 const SubobjectDesignator &Sub,
2715 ExtractSubobjectHandler Handler = { Info, Result };
2716 return findSubobject(Info, E, Obj, Sub, Handler);
2720 struct ModifySubobjectHandler {
2725 typedef bool result_type;
2726 static const AccessKinds AccessKind = AK_Assign;
2728 bool checkConst(QualType QT) {
2729 // Assigning to a const object has undefined behavior.
2730 if (QT.isConstQualified()) {
2731 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
2737 bool failed() { return false; }
2738 bool found(APValue &Subobj, QualType SubobjType) {
2739 if (!checkConst(SubobjType))
2741 // We've been given ownership of NewVal, so just swap it in.
2742 Subobj.swap(NewVal);
2745 bool found(APSInt &Value, QualType SubobjType) {
2746 if (!checkConst(SubobjType))
2748 if (!NewVal.isInt()) {
2749 // Maybe trying to write a cast pointer value into a complex?
2753 Value = NewVal.getInt();
2756 bool found(APFloat &Value, QualType SubobjType) {
2757 if (!checkConst(SubobjType))
2759 Value = NewVal.getFloat();
2762 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
2763 llvm_unreachable("shouldn't encounter string elements with ExpandArrays");
2766 } // end anonymous namespace
2768 const AccessKinds ModifySubobjectHandler::AccessKind;
2770 /// Update the designated sub-object of an rvalue to the given value.
2771 static bool modifySubobject(EvalInfo &Info, const Expr *E,
2772 const CompleteObject &Obj,
2773 const SubobjectDesignator &Sub,
2775 ModifySubobjectHandler Handler = { Info, NewVal, E };
2776 return findSubobject(Info, E, Obj, Sub, Handler);
2779 /// Find the position where two subobject designators diverge, or equivalently
2780 /// the length of the common initial subsequence.
2781 static unsigned FindDesignatorMismatch(QualType ObjType,
2782 const SubobjectDesignator &A,
2783 const SubobjectDesignator &B,
2784 bool &WasArrayIndex) {
2785 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
2786 for (/**/; I != N; ++I) {
2787 if (!ObjType.isNull() &&
2788 (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
2789 // Next subobject is an array element.
2790 if (A.Entries[I].ArrayIndex != B.Entries[I].ArrayIndex) {
2791 WasArrayIndex = true;
2794 if (ObjType->isAnyComplexType())
2795 ObjType = ObjType->castAs<ComplexType>()->getElementType();
2797 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
2799 if (A.Entries[I].BaseOrMember != B.Entries[I].BaseOrMember) {
2800 WasArrayIndex = false;
2803 if (const FieldDecl *FD = getAsField(A.Entries[I]))
2804 // Next subobject is a field.
2805 ObjType = FD->getType();
2807 // Next subobject is a base class.
2808 ObjType = QualType();
2811 WasArrayIndex = false;
2815 /// Determine whether the given subobject designators refer to elements of the
2816 /// same array object.
2817 static bool AreElementsOfSameArray(QualType ObjType,
2818 const SubobjectDesignator &A,
2819 const SubobjectDesignator &B) {
2820 if (A.Entries.size() != B.Entries.size())
2823 bool IsArray = A.MostDerivedIsArrayElement;
2824 if (IsArray && A.MostDerivedPathLength != A.Entries.size())
2825 // A is a subobject of the array element.
2828 // If A (and B) designates an array element, the last entry will be the array
2829 // index. That doesn't have to match. Otherwise, we're in the 'implicit array
2830 // of length 1' case, and the entire path must match.
2832 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
2833 return CommonLength >= A.Entries.size() - IsArray;
2836 /// Find the complete object to which an LValue refers.
2837 static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
2838 AccessKinds AK, const LValue &LVal,
2839 QualType LValType) {
2841 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
2842 return CompleteObject();
2845 CallStackFrame *Frame = nullptr;
2846 if (LVal.CallIndex) {
2847 Frame = Info.getCallFrame(LVal.CallIndex);
2849 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
2850 << AK << LVal.Base.is<const ValueDecl*>();
2851 NoteLValueLocation(Info, LVal.Base);
2852 return CompleteObject();
2856 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
2857 // is not a constant expression (even if the object is non-volatile). We also
2858 // apply this rule to C++98, in order to conform to the expected 'volatile'
2860 if (LValType.isVolatileQualified()) {
2861 if (Info.getLangOpts().CPlusPlus)
2862 Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
2866 return CompleteObject();
2869 // Compute value storage location and type of base object.
2870 APValue *BaseVal = nullptr;
2871 QualType BaseType = getType(LVal.Base);
2873 if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl*>()) {
2874 // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
2875 // In C++11, constexpr, non-volatile variables initialized with constant
2876 // expressions are constant expressions too. Inside constexpr functions,
2877 // parameters are constant expressions even if they're non-const.
2878 // In C++1y, objects local to a constant expression (those with a Frame) are
2879 // both readable and writable inside constant expressions.
2880 // In C, such things can also be folded, although they are not ICEs.
2881 const VarDecl *VD = dyn_cast<VarDecl>(D);
2883 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
2886 if (!VD || VD->isInvalidDecl()) {
2888 return CompleteObject();
2891 // Accesses of volatile-qualified objects are not allowed.
2892 if (BaseType.isVolatileQualified()) {
2893 if (Info.getLangOpts().CPlusPlus) {
2894 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
2896 Info.Note(VD->getLocation(), diag::note_declared_at);
2900 return CompleteObject();
2903 // Unless we're looking at a local variable or argument in a constexpr call,
2904 // the variable we're reading must be const.
2906 if (Info.getLangOpts().CPlusPlus14 &&
2907 VD == Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()) {
2908 // OK, we can read and modify an object if we're in the process of
2909 // evaluating its initializer, because its lifetime began in this
2911 } else if (AK != AK_Read) {
2912 // All the remaining cases only permit reading.
2913 Info.FFDiag(E, diag::note_constexpr_modify_global);
2914 return CompleteObject();
2915 } else if (VD->isConstexpr()) {
2916 // OK, we can read this variable.
2917 } else if (BaseType->isIntegralOrEnumerationType()) {
2918 // In OpenCL if a variable is in constant address space it is a const value.
2919 if (!(BaseType.isConstQualified() ||
2920 (Info.getLangOpts().OpenCL &&
2921 BaseType.getAddressSpace() == LangAS::opencl_constant))) {
2922 if (Info.getLangOpts().CPlusPlus) {
2923 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
2924 Info.Note(VD->getLocation(), diag::note_declared_at);
2928 return CompleteObject();
2930 } else if (BaseType->isFloatingType() && BaseType.isConstQualified()) {
2931 // We support folding of const floating-point types, in order to make
2932 // static const data members of such types (supported as an extension)
2934 if (Info.getLangOpts().CPlusPlus11) {
2935 Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
2936 Info.Note(VD->getLocation(), diag::note_declared_at);
2940 } else if (BaseType.isConstQualified() && VD->hasDefinition(Info.Ctx)) {
2941 Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr) << VD;
2942 // Keep evaluating to see what we can do.
2944 // FIXME: Allow folding of values of any literal type in all languages.
2945 if (Info.checkingPotentialConstantExpression() &&
2946 VD->getType().isConstQualified() && !VD->hasDefinition(Info.Ctx)) {
2947 // The definition of this variable could be constexpr. We can't
2948 // access it right now, but may be able to in future.
2949 } else if (Info.getLangOpts().CPlusPlus11) {
2950 Info.FFDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD;
2951 Info.Note(VD->getLocation(), diag::note_declared_at);
2955 return CompleteObject();
2959 if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal))
2960 return CompleteObject();
2962 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
2965 if (const MaterializeTemporaryExpr *MTE =
2966 dyn_cast<MaterializeTemporaryExpr>(Base)) {
2967 assert(MTE->getStorageDuration() == SD_Static &&
2968 "should have a frame for a non-global materialized temporary");
2970 // Per C++1y [expr.const]p2:
2971 // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
2972 // - a [...] glvalue of integral or enumeration type that refers to
2973 // a non-volatile const object [...]
2975 // - a [...] glvalue of literal type that refers to a non-volatile
2976 // object whose lifetime began within the evaluation of e.
2978 // C++11 misses the 'began within the evaluation of e' check and
2979 // instead allows all temporaries, including things like:
2982 // constexpr int k = r;
2983 // Therefore we use the C++1y rules in C++11 too.
2984 const ValueDecl *VD = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>();
2985 const ValueDecl *ED = MTE->getExtendingDecl();
2986 if (!(BaseType.isConstQualified() &&
2987 BaseType->isIntegralOrEnumerationType()) &&
2988 !(VD && VD->getCanonicalDecl() == ED->getCanonicalDecl())) {
2989 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
2990 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
2991 return CompleteObject();
2994 BaseVal = Info.Ctx.getMaterializedTemporaryValue(MTE, false);
2995 assert(BaseVal && "got reference to unevaluated temporary");
2998 return CompleteObject();
3001 BaseVal = Frame->getTemporary(Base);
3002 assert(BaseVal && "missing value for temporary");
3005 // Volatile temporary objects cannot be accessed in constant expressions.
3006 if (BaseType.isVolatileQualified()) {
3007 if (Info.getLangOpts().CPlusPlus) {
3008 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
3010 Info.Note(Base->getExprLoc(), diag::note_constexpr_temporary_here);
3014 return CompleteObject();
3018 // During the construction of an object, it is not yet 'const'.
3019 // FIXME: We don't set up EvaluatingDecl for local variables or temporaries,
3020 // and this doesn't do quite the right thing for const subobjects of the
3021 // object under construction.
3022 if (LVal.getLValueBase() == Info.EvaluatingDecl) {
3023 BaseType = Info.Ctx.getCanonicalType(BaseType);
3024 BaseType.removeLocalConst();
3027 // In C++1y, we can't safely access any mutable state when we might be
3028 // evaluating after an unmodeled side effect.
3030 // FIXME: Not all local state is mutable. Allow local constant subobjects
3031 // to be read here (but take care with 'mutable' fields).
3032 if ((Frame && Info.getLangOpts().CPlusPlus14 &&
3033 Info.EvalStatus.HasSideEffects) ||
3034 (AK != AK_Read && Info.IsSpeculativelyEvaluating))
3035 return CompleteObject();
3037 return CompleteObject(BaseVal, BaseType);
3040 /// \brief Perform an lvalue-to-rvalue conversion on the given glvalue. This
3041 /// can also be used for 'lvalue-to-lvalue' conversions for looking up the
3042 /// glvalue referred to by an entity of reference type.
3044 /// \param Info - Information about the ongoing evaluation.
3045 /// \param Conv - The expression for which we are performing the conversion.
3046 /// Used for diagnostics.
3047 /// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
3048 /// case of a non-class type).
3049 /// \param LVal - The glvalue on which we are attempting to perform this action.
3050 /// \param RVal - The produced value will be placed here.
3051 static bool handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv,
3053 const LValue &LVal, APValue &RVal) {
3054 if (LVal.Designator.Invalid)
3057 // Check for special cases where there is no existing APValue to look at.
3058 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
3059 if (Base && !LVal.CallIndex && !Type.isVolatileQualified()) {
3060 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) {
3061 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
3062 // initializer until now for such expressions. Such an expression can't be
3063 // an ICE in C, so this only matters for fold.
3064 if (Type.isVolatileQualified()) {
3069 if (!Evaluate(Lit, Info, CLE->getInitializer()))
3071 CompleteObject LitObj(&Lit, Base->getType());
3072 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal);
3073 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) {
3074 // We represent a string literal array as an lvalue pointing at the
3075 // corresponding expression, rather than building an array of chars.
3076 // FIXME: Support ObjCEncodeExpr, MakeStringConstant
3077 APValue Str(Base, CharUnits::Zero(), APValue::NoLValuePath(), 0);
3078 CompleteObject StrObj(&Str, Base->getType());
3079 return extractSubobject(Info, Conv, StrObj, LVal.Designator, RVal);
3083 CompleteObject Obj = findCompleteObject(Info, Conv, AK_Read, LVal, Type);
3084 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal);
3087 /// Perform an assignment of Val to LVal. Takes ownership of Val.
3088 static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
3089 QualType LValType, APValue &Val) {
3090 if (LVal.Designator.Invalid)
3093 if (!Info.getLangOpts().CPlusPlus14) {
3098 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
3099 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
3102 static bool isOverflowingIntegerType(ASTContext &Ctx, QualType T) {
3103 return T->isSignedIntegerType() &&
3104 Ctx.getIntWidth(T) >= Ctx.getIntWidth(Ctx.IntTy);
3108 struct CompoundAssignSubobjectHandler {
3111 QualType PromotedLHSType;
3112 BinaryOperatorKind Opcode;
3115 static const AccessKinds AccessKind = AK_Assign;
3117 typedef bool result_type;
3119 bool checkConst(QualType QT) {
3120 // Assigning to a const object has undefined behavior.
3121 if (QT.isConstQualified()) {
3122 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3128 bool failed() { return false; }
3129 bool found(APValue &Subobj, QualType SubobjType) {
3130 switch (Subobj.getKind()) {
3132 return found(Subobj.getInt(), SubobjType);
3133 case APValue::Float:
3134 return found(Subobj.getFloat(), SubobjType);
3135 case APValue::ComplexInt:
3136 case APValue::ComplexFloat:
3137 // FIXME: Implement complex compound assignment.
3140 case APValue::LValue:
3141 return foundPointer(Subobj, SubobjType);
3143 // FIXME: can this happen?
3148 bool found(APSInt &Value, QualType SubobjType) {
3149 if (!checkConst(SubobjType))
3152 if (!SubobjType->isIntegerType() || !RHS.isInt()) {
3153 // We don't support compound assignment on integer-cast-to-pointer
3159 APSInt LHS = HandleIntToIntCast(Info, E, PromotedLHSType,
3161 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
3163 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
3166 bool found(APFloat &Value, QualType SubobjType) {
3167 return checkConst(SubobjType) &&
3168 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
3170 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
3171 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
3173 bool foundPointer(APValue &Subobj, QualType SubobjType) {
3174 if (!checkConst(SubobjType))
3177 QualType PointeeType;
3178 if (const PointerType *PT = SubobjType->getAs<PointerType>())
3179 PointeeType = PT->getPointeeType();
3181 if (PointeeType.isNull() || !RHS.isInt() ||
3182 (Opcode != BO_Add && Opcode != BO_Sub)) {
3187 int64_t Offset = getExtValue(RHS.getInt());
3188 if (Opcode == BO_Sub)
3192 LVal.setFrom(Info.Ctx, Subobj);
3193 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
3195 LVal.moveInto(Subobj);
3198 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
3199 llvm_unreachable("shouldn't encounter string elements here");
3202 } // end anonymous namespace
3204 const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
3206 /// Perform a compound assignment of LVal <op>= RVal.
3207 static bool handleCompoundAssignment(
3208 EvalInfo &Info, const Expr *E,
3209 const LValue &LVal, QualType LValType, QualType PromotedLValType,
3210 BinaryOperatorKind Opcode, const APValue &RVal) {
3211 if (LVal.Designator.Invalid)
3214 if (!Info.getLangOpts().CPlusPlus14) {
3219 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
3220 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
3222 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
3226 struct IncDecSubobjectHandler {
3229 AccessKinds AccessKind;
3232 typedef bool result_type;
3234 bool checkConst(QualType QT) {
3235 // Assigning to a const object has undefined behavior.
3236 if (QT.isConstQualified()) {
3237 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3243 bool failed() { return false; }
3244 bool found(APValue &Subobj, QualType SubobjType) {
3245 // Stash the old value. Also clear Old, so we don't clobber it later
3246 // if we're post-incrementing a complex.
3252 switch (Subobj.getKind()) {
3254 return found(Subobj.getInt(), SubobjType);
3255 case APValue::Float:
3256 return found(Subobj.getFloat(), SubobjType);
3257 case APValue::ComplexInt:
3258 return found(Subobj.getComplexIntReal(),
3259 SubobjType->castAs<ComplexType>()->getElementType()
3260 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
3261 case APValue::ComplexFloat:
3262 return found(Subobj.getComplexFloatReal(),
3263 SubobjType->castAs<ComplexType>()->getElementType()
3264 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
3265 case APValue::LValue:
3266 return foundPointer(Subobj, SubobjType);
3268 // FIXME: can this happen?
3273 bool found(APSInt &Value, QualType SubobjType) {
3274 if (!checkConst(SubobjType))
3277 if (!SubobjType->isIntegerType()) {
3278 // We don't support increment / decrement on integer-cast-to-pointer
3284 if (Old) *Old = APValue(Value);
3286 // bool arithmetic promotes to int, and the conversion back to bool
3287 // doesn't reduce mod 2^n, so special-case it.
3288 if (SubobjType->isBooleanType()) {
3289 if (AccessKind == AK_Increment)
3296 bool WasNegative = Value.isNegative();
3297 if (AccessKind == AK_Increment) {
3300 if (!WasNegative && Value.isNegative() &&
3301 isOverflowingIntegerType(Info.Ctx, SubobjType)) {
3302 APSInt ActualValue(Value, /*IsUnsigned*/true);
3303 return HandleOverflow(Info, E, ActualValue, SubobjType);
3308 if (WasNegative && !Value.isNegative() &&
3309 isOverflowingIntegerType(Info.Ctx, SubobjType)) {
3310 unsigned BitWidth = Value.getBitWidth();
3311 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
3312 ActualValue.setBit(BitWidth);
3313 return HandleOverflow(Info, E, ActualValue, SubobjType);
3318 bool found(APFloat &Value, QualType SubobjType) {
3319 if (!checkConst(SubobjType))
3322 if (Old) *Old = APValue(Value);
3324 APFloat One(Value.getSemantics(), 1);
3325 if (AccessKind == AK_Increment)
3326 Value.add(One, APFloat::rmNearestTiesToEven);
3328 Value.subtract(One, APFloat::rmNearestTiesToEven);
3331 bool foundPointer(APValue &Subobj, QualType SubobjType) {
3332 if (!checkConst(SubobjType))
3335 QualType PointeeType;
3336 if (const PointerType *PT = SubobjType->getAs<PointerType>())
3337 PointeeType = PT->getPointeeType();
3344 LVal.setFrom(Info.Ctx, Subobj);
3345 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
3346 AccessKind == AK_Increment ? 1 : -1))
3348 LVal.moveInto(Subobj);
3351 bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) {
3352 llvm_unreachable("shouldn't encounter string elements here");
3355 } // end anonymous namespace
3357 /// Perform an increment or decrement on LVal.
3358 static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
3359 QualType LValType, bool IsIncrement, APValue *Old) {
3360 if (LVal.Designator.Invalid)
3363 if (!Info.getLangOpts().CPlusPlus14) {
3368 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
3369 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
3370 IncDecSubobjectHandler Handler = { Info, E, AK, Old };
3371 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
3374 /// Build an lvalue for the object argument of a member function call.
3375 static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
3377 if (Object->getType()->isPointerType())
3378 return EvaluatePointer(Object, This, Info);
3380 if (Object->isGLValue())
3381 return EvaluateLValue(Object, This, Info);
3383 if (Object->getType()->isLiteralType(Info.Ctx))
3384 return EvaluateTemporary(Object, This, Info);
3386 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
3390 /// HandleMemberPointerAccess - Evaluate a member access operation and build an
3391 /// lvalue referring to the result.
3393 /// \param Info - Information about the ongoing evaluation.
3394 /// \param LV - An lvalue referring to the base of the member pointer.
3395 /// \param RHS - The member pointer expression.
3396 /// \param IncludeMember - Specifies whether the member itself is included in
3397 /// the resulting LValue subobject designator. This is not possible when
3398 /// creating a bound member function.
3399 /// \return The field or method declaration to which the member pointer refers,
3400 /// or 0 if evaluation fails.
3401 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
3405 bool IncludeMember = true) {
3407 if (!EvaluateMemberPointer(RHS, MemPtr, Info))
3410 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
3411 // member value, the behavior is undefined.
3412 if (!MemPtr.getDecl()) {
3413 // FIXME: Specific diagnostic.
3418 if (MemPtr.isDerivedMember()) {
3419 // This is a member of some derived class. Truncate LV appropriately.
3420 // The end of the derived-to-base path for the base object must match the
3421 // derived-to-base path for the member pointer.
3422 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
3423 LV.Designator.Entries.size()) {
3427 unsigned PathLengthToMember =
3428 LV.Designator.Entries.size() - MemPtr.Path.size();
3429 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
3430 const CXXRecordDecl *LVDecl = getAsBaseClass(
3431 LV.Designator.Entries[PathLengthToMember + I]);
3432 const CXXRecordDecl *MPDecl = MemPtr.Path[I];
3433 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
3439 // Truncate the lvalue to the appropriate derived class.
3440 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
3441 PathLengthToMember))
3443 } else if (!MemPtr.Path.empty()) {
3444 // Extend the LValue path with the member pointer's path.
3445 LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
3446 MemPtr.Path.size() + IncludeMember);
3448 // Walk down to the appropriate base class.
3449 if (const PointerType *PT = LVType->getAs<PointerType>())
3450 LVType = PT->getPointeeType();
3451 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
3452 assert(RD && "member pointer access on non-class-type expression");
3453 // The first class in the path is that of the lvalue.
3454 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
3455 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
3456 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base))
3460 // Finally cast to the class containing the member.
3461 if (!HandleLValueDirectBase(Info, RHS, LV, RD,
3462 MemPtr.getContainingRecord()))
3466 // Add the member. Note that we cannot build bound member functions here.
3467 if (IncludeMember) {
3468 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) {
3469 if (!HandleLValueMember(Info, RHS, LV, FD))
3471 } else if (const IndirectFieldDecl *IFD =
3472 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) {
3473 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD))
3476 llvm_unreachable("can't construct reference to bound member function");
3480 return MemPtr.getDecl();
3483 static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
3484 const BinaryOperator *BO,
3486 bool IncludeMember = true) {
3487 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI);
3489 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) {
3490 if (Info.noteFailure()) {
3492 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info);
3497 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV,
3498 BO->getRHS(), IncludeMember);
3501 /// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
3502 /// the provided lvalue, which currently refers to the base object.
3503 static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
3505 SubobjectDesignator &D = Result.Designator;
3506 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
3509 QualType TargetQT = E->getType();
3510 if (const PointerType *PT = TargetQT->getAs<PointerType>())
3511 TargetQT = PT->getPointeeType();
3513 // Check this cast lands within the final derived-to-base subobject path.
3514 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
3515 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
3516 << D.MostDerivedType << TargetQT;
3520 // Check the type of the final cast. We don't need to check the path,
3521 // since a cast can only be formed if the path is unique.
3522 unsigned NewEntriesSize = D.Entries.size() - E->path_size();
3523 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
3524 const CXXRecordDecl *FinalType;
3525 if (NewEntriesSize == D.MostDerivedPathLength)
3526 FinalType = D.MostDerivedType->getAsCXXRecordDecl();
3528 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
3529 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
3530 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
3531 << D.MostDerivedType << TargetQT;
3535 // Truncate the lvalue to the appropriate derived class.
3536 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
3540 enum EvalStmtResult {
3541 /// Evaluation failed.
3543 /// Hit a 'return' statement.
3545 /// Evaluation succeeded.
3547 /// Hit a 'continue' statement.
3549 /// Hit a 'break' statement.
3551 /// Still scanning for 'case' or 'default' statement.
3556 static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
3557 // We don't need to evaluate the initializer for a static local.
3558 if (!VD->hasLocalStorage())
3562 Result.set(VD, Info.CurrentCall->Index);
3563 APValue &Val = Info.CurrentCall->createTemporary(VD, true);
3565 const Expr *InitE = VD->getInit();
3567 Info.FFDiag(VD->getLocStart(), diag::note_constexpr_uninitialized)
3568 << false << VD->getType();
3573 if (InitE->isValueDependent())
3576 if (!EvaluateInPlace(Val, Info, Result, InitE)) {
3577 // Wipe out any partially-computed value, to allow tracking that this
3578 // evaluation failed.
3586 static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
3589 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
3590 OK &= EvaluateVarDecl(Info, VD);
3592 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D))
3593 for (auto *BD : DD->bindings())
3594 if (auto *VD = BD->getHoldingVar())
3595 OK &= EvaluateDecl(Info, VD);
3601 /// Evaluate a condition (either a variable declaration or an expression).
3602 static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
3603 const Expr *Cond, bool &Result) {
3604 FullExpressionRAII Scope(Info);
3605 if (CondDecl && !EvaluateDecl(Info, CondDecl))
3607 return EvaluateAsBooleanCondition(Cond, Result, Info);
3611 /// \brief A location where the result (returned value) of evaluating a
3612 /// statement should be stored.
3614 /// The APValue that should be filled in with the returned value.
3616 /// The location containing the result, if any (used to support RVO).
3621 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
3623 const SwitchCase *SC = nullptr);
3625 /// Evaluate the body of a loop, and translate the result as appropriate.
3626 static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
3628 const SwitchCase *Case = nullptr) {
3629 BlockScopeRAII Scope(Info);
3630 switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case)) {
3632 return ESR_Succeeded;
3635 return ESR_Continue;
3638 case ESR_CaseNotFound:
3641 llvm_unreachable("Invalid EvalStmtResult!");
3644 /// Evaluate a switch statement.
3645 static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
3646 const SwitchStmt *SS) {
3647 BlockScopeRAII Scope(Info);
3649 // Evaluate the switch condition.
3652 FullExpressionRAII Scope(Info);
3653 if (const Stmt *Init = SS->getInit()) {
3654 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
3655 if (ESR != ESR_Succeeded)
3658 if (SS->getConditionVariable() &&
3659 !EvaluateDecl(Info, SS->getConditionVariable()))
3661 if (!EvaluateInteger(SS->getCond(), Value, Info))
3665 // Find the switch case corresponding to the value of the condition.
3666 // FIXME: Cache this lookup.
3667 const SwitchCase *Found = nullptr;
3668 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
3669 SC = SC->getNextSwitchCase()) {
3670 if (isa<DefaultStmt>(SC)) {
3675 const CaseStmt *CS = cast<CaseStmt>(SC);
3676 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx);
3677 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx)
3679 if (LHS <= Value && Value <= RHS) {
3686 return ESR_Succeeded;
3688 // Search the switch body for the switch case and evaluate it from there.
3689 switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found)) {
3691 return ESR_Succeeded;
3697 case ESR_CaseNotFound:
3698 // This can only happen if the switch case is nested within a statement
3699 // expression. We have no intention of supporting that.
3700 Info.FFDiag(Found->getLocStart(), diag::note_constexpr_stmt_expr_unsupported);
3703 llvm_unreachable("Invalid EvalStmtResult!");
3706 // Evaluate a statement.
3707 static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
3708 const Stmt *S, const SwitchCase *Case) {
3709 if (!Info.nextStep(S))
3712 // If we're hunting down a 'case' or 'default' label, recurse through
3713 // substatements until we hit the label.
3715 // FIXME: We don't start the lifetime of objects whose initialization we
3716 // jump over. However, such objects must be of class type with a trivial
3717 // default constructor that initialize all subobjects, so must be empty,
3718 // so this almost never matters.
3719 switch (S->getStmtClass()) {
3720 case Stmt::CompoundStmtClass:
3721 // FIXME: Precompute which substatement of a compound statement we
3722 // would jump to, and go straight there rather than performing a
3723 // linear scan each time.
3724 case Stmt::LabelStmtClass:
3725 case Stmt::AttributedStmtClass:
3726 case Stmt::DoStmtClass:
3729 case Stmt::CaseStmtClass:
3730 case Stmt::DefaultStmtClass:
3735 case Stmt::IfStmtClass: {
3736 // FIXME: Precompute which side of an 'if' we would jump to, and go
3737 // straight there rather than scanning both sides.
3738 const IfStmt *IS = cast<IfStmt>(S);
3740 // Wrap the evaluation in a block scope, in case it's a DeclStmt
3741 // preceded by our switch label.
3742 BlockScopeRAII Scope(Info);
3744 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case);
3745 if (ESR != ESR_CaseNotFound || !IS->getElse())
3747 return EvaluateStmt(Result, Info, IS->getElse(), Case);
3750 case Stmt::WhileStmtClass: {
3751 EvalStmtResult ESR =
3752 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case);
3753 if (ESR != ESR_Continue)
3758 case Stmt::ForStmtClass: {
3759 const ForStmt *FS = cast<ForStmt>(S);
3760 EvalStmtResult ESR =
3761 EvaluateLoopBody(Result, Info, FS->getBody(), Case);
3762 if (ESR != ESR_Continue)
3765 FullExpressionRAII IncScope(Info);
3766 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3772 case Stmt::DeclStmtClass:
3773 // FIXME: If the variable has initialization that can't be jumped over,
3774 // bail out of any immediately-surrounding compound-statement too.
3776 return ESR_CaseNotFound;
3780 switch (S->getStmtClass()) {
3782 if (const Expr *E = dyn_cast<Expr>(S)) {
3783 // Don't bother evaluating beyond an expression-statement which couldn't
3785 FullExpressionRAII Scope(Info);
3786 if (!EvaluateIgnoredValue(Info, E))
3788 return ESR_Succeeded;
3791 Info.FFDiag(S->getLocStart());
3794 case Stmt::NullStmtClass:
3795 return ESR_Succeeded;
3797 case Stmt::DeclStmtClass: {
3798 const DeclStmt *DS = cast<DeclStmt>(S);
3799 for (const auto *DclIt : DS->decls()) {
3800 // Each declaration initialization is its own full-expression.
3801 // FIXME: This isn't quite right; if we're performing aggregate
3802 // initialization, each braced subexpression is its own full-expression.
3803 FullExpressionRAII Scope(Info);
3804 if (!EvaluateDecl(Info, DclIt) && !Info.noteFailure())
3807 return ESR_Succeeded;
3810 case Stmt::ReturnStmtClass: {
3811 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
3812 FullExpressionRAII Scope(Info);
3815 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr)
3816 : Evaluate(Result.Value, Info, RetExpr)))
3818 return ESR_Returned;
3821 case Stmt::CompoundStmtClass: {
3822 BlockScopeRAII Scope(Info);
3824 const CompoundStmt *CS = cast<CompoundStmt>(S);
3825 for (const auto *BI : CS->body()) {
3826 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case);
3827 if (ESR == ESR_Succeeded)
3829 else if (ESR != ESR_CaseNotFound)
3832 return Case ? ESR_CaseNotFound : ESR_Succeeded;
3835 case Stmt::IfStmtClass: {
3836 const IfStmt *IS = cast<IfStmt>(S);
3838 // Evaluate the condition, as either a var decl or as an expression.
3839 BlockScopeRAII Scope(Info);
3840 if (const Stmt *Init = IS->getInit()) {
3841 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
3842 if (ESR != ESR_Succeeded)
3846 if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
3849 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
3850 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
3851 if (ESR != ESR_Succeeded)
3854 return ESR_Succeeded;
3857 case Stmt::WhileStmtClass: {
3858 const WhileStmt *WS = cast<WhileStmt>(S);
3860 BlockScopeRAII Scope(Info);
3862 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
3868 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
3869 if (ESR != ESR_Continue)
3872 return ESR_Succeeded;
3875 case Stmt::DoStmtClass: {
3876 const DoStmt *DS = cast<DoStmt>(S);
3879 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case);
3880 if (ESR != ESR_Continue)
3884 FullExpressionRAII CondScope(Info);
3885 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info))
3888 return ESR_Succeeded;
3891 case Stmt::ForStmtClass: {
3892 const ForStmt *FS = cast<ForStmt>(S);
3893 BlockScopeRAII Scope(Info);
3894 if (FS->getInit()) {
3895 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
3896 if (ESR != ESR_Succeeded)
3900 BlockScopeRAII Scope(Info);
3901 bool Continue = true;
3902 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
3903 FS->getCond(), Continue))
3908 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
3909 if (ESR != ESR_Continue)
3913 FullExpressionRAII IncScope(Info);
3914 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3918 return ESR_Succeeded;
3921 case Stmt::CXXForRangeStmtClass: {
3922 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S);
3923 BlockScopeRAII Scope(Info);
3925 // Initialize the __range variable.
3926 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt());
3927 if (ESR != ESR_Succeeded)
3930 // Create the __begin and __end iterators.
3931 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt());
3932 if (ESR != ESR_Succeeded)
3934 ESR = EvaluateStmt(Result, Info, FS->getEndStmt());
3935 if (ESR != ESR_Succeeded)
3939 // Condition: __begin != __end.
3941 bool Continue = true;
3942 FullExpressionRAII CondExpr(Info);
3943 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info))
3949 // User's variable declaration, initialized by *__begin.
3950 BlockScopeRAII InnerScope(Info);
3951 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt());
3952 if (ESR != ESR_Succeeded)
3956 ESR = EvaluateLoopBody(Result, Info, FS->getBody());
3957 if (ESR != ESR_Continue)
3960 // Increment: ++__begin
3961 if (!EvaluateIgnoredValue(Info, FS->getInc()))
3965 return ESR_Succeeded;
3968 case Stmt::SwitchStmtClass:
3969 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S));
3971 case Stmt::ContinueStmtClass:
3972 return ESR_Continue;
3974 case Stmt::BreakStmtClass:
3977 case Stmt::LabelStmtClass:
3978 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case);
3980 case Stmt::AttributedStmtClass:
3981 // As a general principle, C++11 attributes can be ignored without
3982 // any semantic impact.
3983 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(),
3986 case Stmt::CaseStmtClass:
3987 case Stmt::DefaultStmtClass:
3988 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case);
3992 /// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
3993 /// default constructor. If so, we'll fold it whether or not it's marked as
3994 /// constexpr. If it is marked as constexpr, we will never implicitly define it,
3995 /// so we need special handling.
3996 static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
3997 const CXXConstructorDecl *CD,
3998 bool IsValueInitialization) {
3999 if (!CD->isTrivial() || !CD->isDefaultConstructor())
4002 // Value-initialization does not call a trivial default constructor, so such a
4003 // call is a core constant expression whether or not the constructor is
4005 if (!CD->isConstexpr() && !IsValueInitialization) {
4006 if (Info.getLangOpts().CPlusPlus11) {
4007 // FIXME: If DiagDecl is an implicitly-declared special member function,
4008 // we should be much more explicit about why it's not constexpr.
4009 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
4010 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
4011 Info.Note(CD->getLocation(), diag::note_declared_at);
4013 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
4019 /// CheckConstexprFunction - Check that a function can be called in a constant
4021 static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
4022 const FunctionDecl *Declaration,
4023 const FunctionDecl *Definition,
4025 // Potential constant expressions can contain calls to declared, but not yet
4026 // defined, constexpr functions.
4027 if (Info.checkingPotentialConstantExpression() && !Definition &&
4028 Declaration->isConstexpr())
4031 // Bail out with no diagnostic if the function declaration itself is invalid.
4032 // We will have produced a relevant diagnostic while parsing it.
4033 if (Declaration->isInvalidDecl())
4036 // Can we evaluate this function call?
4037 if (Definition && Definition->isConstexpr() &&
4038 !Definition->isInvalidDecl() && Body)
4041 if (Info.getLangOpts().CPlusPlus11) {
4042 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
4044 // If this function is not constexpr because it is an inherited
4045 // non-constexpr constructor, diagnose that directly.
4046 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
4047 if (CD && CD->isInheritingConstructor()) {
4048 auto *Inherited = CD->getInheritedConstructor().getConstructor();
4049 if (!Inherited->isConstexpr())
4050 DiagDecl = CD = Inherited;
4053 // FIXME: If DiagDecl is an implicitly-declared special member function
4054 // or an inheriting constructor, we should be much more explicit about why
4055 // it's not constexpr.
4056 if (CD && CD->isInheritingConstructor())
4057 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
4058 << CD->getInheritedConstructor().getConstructor()->getParent();
4060 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
4061 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
4062 Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
4064 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
4069 /// Determine if a class has any fields that might need to be copied by a
4070 /// trivial copy or move operation.
4071 static bool hasFields(const CXXRecordDecl *RD) {
4072 if (!RD || RD->isEmpty())
4074 for (auto *FD : RD->fields()) {
4075 if (FD->isUnnamedBitfield())
4079 for (auto &Base : RD->bases())
4080 if (hasFields(Base.getType()->getAsCXXRecordDecl()))
4086 typedef SmallVector<APValue, 8> ArgVector;
4089 /// EvaluateArgs - Evaluate the arguments to a function call.
4090 static bool EvaluateArgs(ArrayRef<const Expr*> Args, ArgVector &ArgValues,
4092 bool Success = true;
4093 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
4095 if (!Evaluate(ArgValues[I - Args.begin()], Info, *I)) {
4096 // If we're checking for a potential constant expression, evaluate all
4097 // initializers even if some of them fail.
4098 if (!Info.noteFailure())
4106 /// Evaluate a function call.
4107 static bool HandleFunctionCall(SourceLocation CallLoc,
4108 const FunctionDecl *Callee, const LValue *This,
4109 ArrayRef<const Expr*> Args, const Stmt *Body,
4110 EvalInfo &Info, APValue &Result,
4111 const LValue *ResultSlot) {
4112 ArgVector ArgValues(Args.size());
4113 if (!EvaluateArgs(Args, ArgValues, Info))
4116 if (!Info.CheckCallLimit(CallLoc))
4119 CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data());
4121 // For a trivial copy or move assignment, perform an APValue copy. This is
4122 // essential for unions, where the operations performed by the assignment
4123 // operator cannot be represented as statements.
4125 // Skip this for non-union classes with no fields; in that case, the defaulted
4126 // copy/move does not actually read the object.
4127 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee);
4128 if (MD && MD->isDefaulted() &&
4129 (MD->getParent()->isUnion() ||
4130 (MD->isTrivial() && hasFields(MD->getParent())))) {
4132 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()));
4134 RHS.setFrom(Info.Ctx, ArgValues[0]);
4136 if (!handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(),
4139 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(Info.Ctx),
4142 This->moveInto(Result);
4146 StmtResult Ret = {Result, ResultSlot};
4147 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body);
4148 if (ESR == ESR_Succeeded) {
4149 if (Callee->getReturnType()->isVoidType())
4151 Info.FFDiag(Callee->getLocEnd(), diag::note_constexpr_no_return);
4153 return ESR == ESR_Returned;
4156 /// Evaluate a constructor call.
4157 static bool HandleConstructorCall(const Expr *E, const LValue &This,
4159 const CXXConstructorDecl *Definition,
4160 EvalInfo &Info, APValue &Result) {
4161 SourceLocation CallLoc = E->getExprLoc();
4162 if (!Info.CheckCallLimit(CallLoc))
4165 const CXXRecordDecl *RD = Definition->getParent();
4166 if (RD->getNumVBases()) {
4167 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
4171 CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues);
4173 // FIXME: Creating an APValue just to hold a nonexistent return value is
4176 StmtResult Ret = {RetVal, nullptr};
4178 // If it's a delegating constructor, delegate.
4179 if (Definition->isDelegatingConstructor()) {
4180 CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
4182 FullExpressionRAII InitScope(Info);
4183 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()))
4186 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
4189 // For a trivial copy or move constructor, perform an APValue copy. This is
4190 // essential for unions (or classes with anonymous union members), where the
4191 // operations performed by the constructor cannot be represented by
4192 // ctor-initializers.
4194 // Skip this for empty non-union classes; we should not perform an
4195 // lvalue-to-rvalue conversion on them because their copy constructor does not
4196 // actually read them.
4197 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
4198 (Definition->getParent()->isUnion() ||
4199 (Definition->isTrivial() && hasFields(Definition->getParent())))) {
4201 RHS.setFrom(Info.Ctx, ArgValues[0]);
4202 return handleLValueToRValueConversion(
4203 Info, E, Definition->getParamDecl(0)->getType().getNonReferenceType(),
4207 // Reserve space for the struct members.
4208 if (!RD->isUnion() && Result.isUninit())
4209 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
4210 std::distance(RD->field_begin(), RD->field_end()));
4212 if (RD->isInvalidDecl()) return false;
4213 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
4215 // A scope for temporaries lifetime-extended by reference members.
4216 BlockScopeRAII LifetimeExtendedScope(Info);
4218 bool Success = true;
4219 unsigned BasesSeen = 0;
4221 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
4223 for (const auto *I : Definition->inits()) {
4224 LValue Subobject = This;
4225 APValue *Value = &Result;
4227 // Determine the subobject to initialize.
4228 FieldDecl *FD = nullptr;
4229 if (I->isBaseInitializer()) {
4230 QualType BaseType(I->getBaseClass(), 0);
4232 // Non-virtual base classes are initialized in the order in the class
4233 // definition. We have already checked for virtual base classes.
4234 assert(!BaseIt->isVirtual() && "virtual base for literal type");
4235 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
4236 "base class initializers not in expected order");
4239 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD,
4240 BaseType->getAsCXXRecordDecl(), &Layout))
4242 Value = &Result.getStructBase(BasesSeen++);
4243 } else if ((FD = I->getMember())) {
4244 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout))
4246 if (RD->isUnion()) {
4247 Result = APValue(FD);
4248 Value = &Result.getUnionValue();
4250 Value = &Result.getStructField(FD->getFieldIndex());
4252 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
4253 // Walk the indirect field decl's chain to find the object to initialize,
4254 // and make sure we've initialized every step along it.
4255 for (auto *C : IFD->chain()) {
4256 FD = cast<FieldDecl>(C);
4257 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
4258 // Switch the union field if it differs. This happens if we had
4259 // preceding zero-initialization, and we're now initializing a union
4260 // subobject other than the first.
4261 // FIXME: In this case, the values of the other subobjects are
4262 // specified, since zero-initialization sets all padding bits to zero.
4263 if (Value->isUninit() ||
4264 (Value->isUnion() && Value->getUnionField() != FD)) {
4266 *Value = APValue(FD);
4268 *Value = APValue(APValue::UninitStruct(), CD->getNumBases(),
4269 std::distance(CD->field_begin(), CD->field_end()));
4271 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
4274 Value = &Value->getUnionValue();
4276 Value = &Value->getStructField(FD->getFieldIndex());
4279 llvm_unreachable("unknown base initializer kind");
4282 FullExpressionRAII InitScope(Info);
4283 if (!EvaluateInPlace(*Value, Info, Subobject, I->getInit()) ||
4284 (FD && FD->isBitField() && !truncateBitfieldValue(Info, I->getInit(),
4286 // If we're checking for a potential constant expression, evaluate all
4287 // initializers even if some of them fail.
4288 if (!Info.noteFailure())
4295 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
4298 static bool HandleConstructorCall(const Expr *E, const LValue &This,
4299 ArrayRef<const Expr*> Args,
4300 const CXXConstructorDecl *Definition,
4301 EvalInfo &Info, APValue &Result) {
4302 ArgVector ArgValues(Args.size());
4303 if (!EvaluateArgs(Args, ArgValues, Info))
4306 return HandleConstructorCall(E, This, ArgValues.data(), Definition,
4310 //===----------------------------------------------------------------------===//
4311 // Generic Evaluation
4312 //===----------------------------------------------------------------------===//
4315 template <class Derived>
4316 class ExprEvaluatorBase
4317 : public ConstStmtVisitor<Derived, bool> {
4319 Derived &getDerived() { return static_cast<Derived&>(*this); }
4320 bool DerivedSuccess(const APValue &V, const Expr *E) {
4321 return getDerived().Success(V, E);
4323 bool DerivedZeroInitialization(const Expr *E) {
4324 return getDerived().ZeroInitialization(E);
4327 // Check whether a conditional operator with a non-constant condition is a
4328 // potential constant expression. If neither arm is a potential constant
4329 // expression, then the conditional operator is not either.
4330 template<typename ConditionalOperator>
4331 void CheckPotentialConstantConditional(const ConditionalOperator *E) {
4332 assert(Info.checkingPotentialConstantExpression());
4334 // Speculatively evaluate both arms.
4335 SmallVector<PartialDiagnosticAt, 8> Diag;
4337 SpeculativeEvaluationRAII Speculate(Info, &Diag);
4338 StmtVisitorTy::Visit(E->getFalseExpr());
4344 SpeculativeEvaluationRAII Speculate(Info, &Diag);
4346 StmtVisitorTy::Visit(E->getTrueExpr());
4351 Error(E, diag::note_constexpr_conditional_never_const);
4355 template<typename ConditionalOperator>
4356 bool HandleConditionalOperator(const ConditionalOperator *E) {
4358 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
4359 if (Info.checkingPotentialConstantExpression() && Info.noteFailure())
4360 CheckPotentialConstantConditional(E);
4364 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
4365 return StmtVisitorTy::Visit(EvalExpr);
4370 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
4371 typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
4373 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
4374 return Info.CCEDiag(E, D);
4377 bool ZeroInitialization(const Expr *E) { return Error(E); }
4380 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
4382 EvalInfo &getEvalInfo() { return Info; }
4384 /// Report an evaluation error. This should only be called when an error is
4385 /// first discovered. When propagating an error, just return false.
4386 bool Error(const Expr *E, diag::kind D) {
4390 bool Error(const Expr *E) {
4391 return Error(E, diag::note_invalid_subexpr_in_const_expr);
4394 bool VisitStmt(const Stmt *) {
4395 llvm_unreachable("Expression evaluator should not be called on stmts");
4397 bool VisitExpr(const Expr *E) {
4401 bool VisitParenExpr(const ParenExpr *E)
4402 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4403 bool VisitUnaryExtension(const UnaryOperator *E)
4404 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4405 bool VisitUnaryPlus(const UnaryOperator *E)
4406 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4407 bool VisitChooseExpr(const ChooseExpr *E)
4408 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
4409 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
4410 { return StmtVisitorTy::Visit(E->getResultExpr()); }
4411 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
4412 { return StmtVisitorTy::Visit(E->getReplacement()); }
4413 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E)
4414 { return StmtVisitorTy::Visit(E->getExpr()); }
4415 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
4416 // The initializer may not have been parsed yet, or might be erroneous.
4419 return StmtVisitorTy::Visit(E->getExpr());
4421 // We cannot create any objects for which cleanups are required, so there is
4422 // nothing to do here; all cleanups must come from unevaluated subexpressions.
4423 bool VisitExprWithCleanups(const ExprWithCleanups *E)
4424 { return StmtVisitorTy::Visit(E->getSubExpr()); }
4426 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
4427 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
4428 return static_cast<Derived*>(this)->VisitCastExpr(E);
4430 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
4431 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
4432 return static_cast<Derived*>(this)->VisitCastExpr(E);
4435 bool VisitBinaryOperator(const BinaryOperator *E) {
4436 switch (E->getOpcode()) {
4441 VisitIgnoredValue(E->getLHS());
4442 return StmtVisitorTy::Visit(E->getRHS());
4447 if (!HandleMemberPointerAccess(Info, E, Obj))
4450 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
4452 return DerivedSuccess(Result, E);
4457 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
4458 // Evaluate and cache the common expression. We treat it as a temporary,
4459 // even though it's not quite the same thing.
4460 if (!Evaluate(Info.CurrentCall->createTemporary(E->getOpaqueValue(), false),
4461 Info, E->getCommon()))
4464 return HandleConditionalOperator(E);
4467 bool VisitConditionalOperator(const ConditionalOperator *E) {
4468 bool IsBcpCall = false;
4469 // If the condition (ignoring parens) is a __builtin_constant_p call,
4470 // the result is a constant expression if it can be folded without
4471 // side-effects. This is an important GNU extension. See GCC PR38377
4473 if (const CallExpr *CallCE =
4474 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
4475 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
4478 // Always assume __builtin_constant_p(...) ? ... : ... is a potential
4479 // constant expression; we can't check whether it's potentially foldable.
4480 if (Info.checkingPotentialConstantExpression() && IsBcpCall)
4483 FoldConstant Fold(Info, IsBcpCall);
4484 if (!HandleConditionalOperator(E)) {
4485 Fold.keepDiagnostics();
4492 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
4493 if (APValue *Value = Info.CurrentCall->getTemporary(E))
4494 return DerivedSuccess(*Value, E);
4496 const Expr *Source = E->getSourceExpr();
4499 if (Source == E) { // sanity checking.
4500 assert(0 && "OpaqueValueExpr recursively refers to itself");
4503 return StmtVisitorTy::Visit(Source);
4506 bool VisitCallExpr(const CallExpr *E) {
4508 if (!handleCallExpr(E, Result, nullptr))
4510 return DerivedSuccess(Result, E);
4513 bool handleCallExpr(const CallExpr *E, APValue &Result,
4514 const LValue *ResultSlot) {
4515 const Expr *Callee = E->getCallee()->IgnoreParens();
4516 QualType CalleeType = Callee->getType();
4518 const FunctionDecl *FD = nullptr;
4519 LValue *This = nullptr, ThisVal;
4520 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
4521 bool HasQualifier = false;
4523 // Extract function decl and 'this' pointer from the callee.
4524 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
4525 const ValueDecl *Member = nullptr;
4526 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
4527 // Explicit bound member calls, such as x.f() or p->g();
4528 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
4530 Member = ME->getMemberDecl();
4532 HasQualifier = ME->hasQualifier();
4533 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
4534 // Indirect bound member calls ('.*' or '->*').
4535 Member = HandleMemberPointerAccess(Info, BE, ThisVal, false);
4536 if (!Member) return false;
4539 return Error(Callee);
4541 FD = dyn_cast<FunctionDecl>(Member);
4543 return Error(Callee);
4544 } else if (CalleeType->isFunctionPointerType()) {
4546 if (!EvaluatePointer(Callee, Call, Info))
4549 if (!Call.getLValueOffset().isZero())
4550 return Error(Callee);
4551 FD = dyn_cast_or_null<FunctionDecl>(
4552 Call.getLValueBase().dyn_cast<const ValueDecl*>());
4554 return Error(Callee);
4555 // Don't call function pointers which have been cast to some other type.
4556 // Per DR (no number yet), the caller and callee can differ in noexcept.
4557 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
4558 CalleeType->getPointeeType(), FD->getType())) {
4562 // Overloaded operator calls to member functions are represented as normal
4563 // calls with '*this' as the first argument.
4564 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
4565 if (MD && !MD->isStatic()) {
4566 // FIXME: When selecting an implicit conversion for an overloaded
4567 // operator delete, we sometimes try to evaluate calls to conversion
4568 // operators without a 'this' parameter!
4572 if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
4575 Args = Args.slice(1);
4576 } else if (MD && MD->isLambdaStaticInvoker()) {
4577 // Map the static invoker for the lambda back to the call operator.
4578 // Conveniently, we don't have to slice out the 'this' argument (as is
4579 // being done for the non-static case), since a static member function
4580 // doesn't have an implicit argument passed in.
4581 const CXXRecordDecl *ClosureClass = MD->getParent();
4583 ClosureClass->captures_begin() == ClosureClass->captures_end() &&
4584 "Number of captures must be zero for conversion to function-ptr");
4586 const CXXMethodDecl *LambdaCallOp =
4587 ClosureClass->getLambdaCallOperator();
4589 // Set 'FD', the function that will be called below, to the call
4590 // operator. If the closure object represents a generic lambda, find
4591 // the corresponding specialization of the call operator.
4593 if (ClosureClass->isGenericLambda()) {
4594 assert(MD->isFunctionTemplateSpecialization() &&
4595 "A generic lambda's static-invoker function must be a "
4596 "template specialization");
4597 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
4598 FunctionTemplateDecl *CallOpTemplate =
4599 LambdaCallOp->getDescribedFunctionTemplate();
4600 void *InsertPos = nullptr;
4601 FunctionDecl *CorrespondingCallOpSpecialization =
4602 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
4603 assert(CorrespondingCallOpSpecialization &&
4604 "We must always have a function call operator specialization "
4605 "that corresponds to our static invoker specialization");
4606 FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
4615 if (This && !This->checkSubobject(Info, E, CSK_This))
4618 // DR1358 allows virtual constexpr functions in some cases. Don't allow
4619 // calls to such functions in constant expressions.
4620 if (This && !HasQualifier &&
4621 isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isVirtual())
4622 return Error(E, diag::note_constexpr_virtual_call);
4624 const FunctionDecl *Definition = nullptr;
4625 Stmt *Body = FD->getBody(Definition);
4627 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
4628 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, Info,
4629 Result, ResultSlot))
4635 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
4636 return StmtVisitorTy::Visit(E->getInitializer());
4638 bool VisitInitListExpr(const InitListExpr *E) {
4639 if (E->getNumInits() == 0)
4640 return DerivedZeroInitialization(E);
4641 if (E->getNumInits() == 1)
4642 return StmtVisitorTy::Visit(E->getInit(0));
4645 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
4646 return DerivedZeroInitialization(E);
4648 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
4649 return DerivedZeroInitialization(E);
4651 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
4652 return DerivedZeroInitialization(E);
4655 /// A member expression where the object is a prvalue is itself a prvalue.
4656 bool VisitMemberExpr(const MemberExpr *E) {
4657 assert(!E->isArrow() && "missing call to bound member function?");
4660 if (!Evaluate(Val, Info, E->getBase()))
4663 QualType BaseTy = E->getBase()->getType();
4665 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
4666 if (!FD) return Error(E);
4667 assert(!FD->getType()->isReferenceType() && "prvalue reference?");
4668 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
4669 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
4671 CompleteObject Obj(&Val, BaseTy);
4672 SubobjectDesignator Designator(BaseTy);
4673 Designator.addDeclUnchecked(FD);
4676 return extractSubobject(Info, E, Obj, Designator, Result) &&
4677 DerivedSuccess(Result, E);
4680 bool VisitCastExpr(const CastExpr *E) {
4681 switch (E->getCastKind()) {
4685 case CK_AtomicToNonAtomic: {
4687 if (!EvaluateAtomic(E->getSubExpr(), AtomicVal, Info))
4689 return DerivedSuccess(AtomicVal, E);
4693 case CK_UserDefinedConversion:
4694 return StmtVisitorTy::Visit(E->getSubExpr());
4696 case CK_LValueToRValue: {
4698 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
4701 // Note, we use the subexpression's type in order to retain cv-qualifiers.
4702 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
4705 return DerivedSuccess(RVal, E);
4712 bool VisitUnaryPostInc(const UnaryOperator *UO) {
4713 return VisitUnaryPostIncDec(UO);
4715 bool VisitUnaryPostDec(const UnaryOperator *UO) {
4716 return VisitUnaryPostIncDec(UO);
4718 bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
4719 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
4723 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info))
4726 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
4727 UO->isIncrementOp(), &RVal))
4729 return DerivedSuccess(RVal, UO);
4732 bool VisitStmtExpr(const StmtExpr *E) {
4733 // We will have checked the full-expressions inside the statement expression
4734 // when they were completed, and don't need to check them again now.
4735 if (Info.checkingForOverflow())
4738 BlockScopeRAII Scope(Info);
4739 const CompoundStmt *CS = E->getSubStmt();
4740 if (CS->body_empty())
4743 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
4744 BE = CS->body_end();
4747 const Expr *FinalExpr = dyn_cast<Expr>(*BI);
4749 Info.FFDiag((*BI)->getLocStart(),
4750 diag::note_constexpr_stmt_expr_unsupported);
4753 return this->Visit(FinalExpr);
4756 APValue ReturnValue;
4757 StmtResult Result = { ReturnValue, nullptr };
4758 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
4759 if (ESR != ESR_Succeeded) {
4760 // FIXME: If the statement-expression terminated due to 'return',
4761 // 'break', or 'continue', it would be nice to propagate that to
4762 // the outer statement evaluation rather than bailing out.
4763 if (ESR != ESR_Failed)
4764 Info.FFDiag((*BI)->getLocStart(),
4765 diag::note_constexpr_stmt_expr_unsupported);
4770 llvm_unreachable("Return from function from the loop above.");
4773 /// Visit a value which is evaluated, but whose value is ignored.
4774 void VisitIgnoredValue(const Expr *E) {
4775 EvaluateIgnoredValue(Info, E);
4778 /// Potentially visit a MemberExpr's base expression.
4779 void VisitIgnoredBaseExpression(const Expr *E) {
4780 // While MSVC doesn't evaluate the base expression, it does diagnose the
4781 // presence of side-effecting behavior.
4782 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
4784 VisitIgnoredValue(E);
4790 //===----------------------------------------------------------------------===//
4791 // Common base class for lvalue and temporary evaluation.
4792 //===----------------------------------------------------------------------===//
4794 template<class Derived>
4795 class LValueExprEvaluatorBase
4796 : public ExprEvaluatorBase<Derived> {
4799 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
4800 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
4802 bool Success(APValue::LValueBase B) {
4808 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result) :
4809 ExprEvaluatorBaseTy(Info), Result(Result) {}
4811 bool Success(const APValue &V, const Expr *E) {
4812 Result.setFrom(this->Info.Ctx, V);
4816 bool VisitMemberExpr(const MemberExpr *E) {
4817 // Handle non-static data members.
4821 EvalOK = EvaluatePointer(E->getBase(), Result, this->Info);
4822 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
4823 } else if (E->getBase()->isRValue()) {
4824 assert(E->getBase()->getType()->isRecordType());
4825 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
4826 BaseTy = E->getBase()->getType();
4828 EvalOK = this->Visit(E->getBase());
4829 BaseTy = E->getBase()->getType();
4832 if (!this->Info.allowInvalidBaseExpr())
4834 Result.setInvalid(E);
4838 const ValueDecl *MD = E->getMemberDecl();
4839 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
4840 assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() ==
4841 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
4843 if (!HandleLValueMember(this->Info, E, Result, FD))
4845 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
4846 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
4849 return this->Error(E);
4851 if (MD->getType()->isReferenceType()) {
4853 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
4856 return Success(RefValue, E);
4861 bool VisitBinaryOperator(const BinaryOperator *E) {
4862 switch (E->getOpcode()) {
4864 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
4868 return HandleMemberPointerAccess(this->Info, E, Result);
4872 bool VisitCastExpr(const CastExpr *E) {
4873 switch (E->getCastKind()) {
4875 return ExprEvaluatorBaseTy::VisitCastExpr(E);
4877 case CK_DerivedToBase:
4878 case CK_UncheckedDerivedToBase:
4879 if (!this->Visit(E->getSubExpr()))
4882 // Now figure out the necessary offset to add to the base LV to get from
4883 // the derived class to the base class.
4884 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
4891 //===----------------------------------------------------------------------===//
4892 // LValue Evaluation
4894 // This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
4895 // function designators (in C), decl references to void objects (in C), and
4896 // temporaries (if building with -Wno-address-of-temporary).
4898 // LValue evaluation produces values comprising a base expression of one of the
4904 // * CompoundLiteralExpr in C (and in global scope in C++)
4908 // * ObjCStringLiteralExpr
4912 // * CallExpr for a MakeStringConstant builtin
4913 // - Locals and temporaries
4914 // * MaterializeTemporaryExpr
4915 // * Any Expr, with a CallIndex indicating the function in which the temporary
4916 // was evaluated, for cases where the MaterializeTemporaryExpr is missing
4917 // from the AST (FIXME).
4918 // * A MaterializeTemporaryExpr that has static storage duration, with no
4919 // CallIndex, for a lifetime-extended temporary.
4920 // plus an offset in bytes.
4921 //===----------------------------------------------------------------------===//
4923 class LValueExprEvaluator
4924 : public LValueExprEvaluatorBase<LValueExprEvaluator> {
4926 LValueExprEvaluator(EvalInfo &Info, LValue &Result) :
4927 LValueExprEvaluatorBaseTy(Info, Result) {}
4929 bool VisitVarDecl(const Expr *E, const VarDecl *VD);
4930 bool VisitUnaryPreIncDec(const UnaryOperator *UO);
4932 bool VisitDeclRefExpr(const DeclRefExpr *E);
4933 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
4934 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
4935 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
4936 bool VisitMemberExpr(const MemberExpr *E);
4937 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
4938 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
4939 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
4940 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
4941 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
4942 bool VisitUnaryDeref(const UnaryOperator *E);
4943 bool VisitUnaryReal(const UnaryOperator *E);
4944 bool VisitUnaryImag(const UnaryOperator *E);
4945 bool VisitUnaryPreInc(const UnaryOperator *UO) {
4946 return VisitUnaryPreIncDec(UO);
4948 bool VisitUnaryPreDec(const UnaryOperator *UO) {
4949 return VisitUnaryPreIncDec(UO);
4951 bool VisitBinAssign(const BinaryOperator *BO);
4952 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
4954 bool VisitCastExpr(const CastExpr *E) {
4955 switch (E->getCastKind()) {
4957 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
4959 case CK_LValueBitCast:
4960 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
4961 if (!Visit(E->getSubExpr()))
4963 Result.Designator.setInvalid();
4966 case CK_BaseToDerived:
4967 if (!Visit(E->getSubExpr()))
4969 return HandleBaseToDerivedCast(Info, E, Result);
4973 } // end anonymous namespace
4975 /// Evaluate an expression as an lvalue. This can be legitimately called on
4976 /// expressions which are not glvalues, in three cases:
4977 /// * function designators in C, and
4978 /// * "extern void" objects
4979 /// * @selector() expressions in Objective-C
4980 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info) {
4981 assert(E->isGLValue() || E->getType()->isFunctionType() ||
4982 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E));
4983 return LValueExprEvaluator(Info, Result).Visit(E);
4986 bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
4987 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl()))
4989 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
4990 return VisitVarDecl(E, VD);
4991 if (const BindingDecl *BD = dyn_cast<BindingDecl>(E->getDecl()))
4992 return Visit(BD->getBinding());
4997 bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
4998 CallStackFrame *Frame = nullptr;
4999 if (VD->hasLocalStorage() && Info.CurrentCall->Index > 1) {
5000 // Only if a local variable was declared in the function currently being
5001 // evaluated, do we expect to be able to find its value in the current
5002 // frame. (Otherwise it was likely declared in an enclosing context and
5003 // could either have a valid evaluatable value (for e.g. a constexpr
5004 // variable) or be ill-formed (and trigger an appropriate evaluation
5006 if (Info.CurrentCall->Callee &&
5007 Info.CurrentCall->Callee->Equals(VD->getDeclContext())) {
5008 Frame = Info.CurrentCall;
5012 if (!VD->getType()->isReferenceType()) {
5014 Result.set(VD, Frame->Index);
5021 if (!evaluateVarDeclInit(Info, E, VD, Frame, V))
5023 if (V->isUninit()) {
5024 if (!Info.checkingPotentialConstantExpression())
5025 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
5028 return Success(*V, E);
5031 bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
5032 const MaterializeTemporaryExpr *E) {
5033 // Walk through the expression to find the materialized temporary itself.
5034 SmallVector<const Expr *, 2> CommaLHSs;
5035 SmallVector<SubobjectAdjustment, 2> Adjustments;
5036 const Expr *Inner = E->GetTemporaryExpr()->
5037 skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
5039 // If we passed any comma operators, evaluate their LHSs.
5040 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
5041 if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
5044 // A materialized temporary with static storage duration can appear within the
5045 // result of a constant expression evaluation, so we need to preserve its
5046 // value for use outside this evaluation.
5048 if (E->getStorageDuration() == SD_Static) {
5049 Value = Info.Ctx.getMaterializedTemporaryValue(E, true);
5053 Value = &Info.CurrentCall->
5054 createTemporary(E, E->getStorageDuration() == SD_Automatic);
5055 Result.set(E, Info.CurrentCall->Index);
5058 QualType Type = Inner->getType();
5060 // Materialize the temporary itself.
5061 if (!EvaluateInPlace(*Value, Info, Result, Inner) ||
5062 (E->getStorageDuration() == SD_Static &&
5063 !CheckConstantExpression(Info, E->getExprLoc(), Type, *Value))) {
5068 // Adjust our lvalue to refer to the desired subobject.
5069 for (unsigned I = Adjustments.size(); I != 0; /**/) {
5071 switch (Adjustments[I].Kind) {
5072 case SubobjectAdjustment::DerivedToBaseAdjustment:
5073 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath,
5076 Type = Adjustments[I].DerivedToBase.BasePath->getType();
5079 case SubobjectAdjustment::FieldAdjustment:
5080 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
5082 Type = Adjustments[I].Field->getType();
5085 case SubobjectAdjustment::MemberPointerAdjustment:
5086 if (!HandleMemberPointerAccess(this->Info, Type, Result,
5087 Adjustments[I].Ptr.RHS))
5089 Type = Adjustments[I].Ptr.MPT->getPointeeType();
5098 LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
5099 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
5100 "lvalue compound literal in c++?");
5101 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
5102 // only see this when folding in C, so there's no standard to follow here.
5106 bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
5107 if (!E->isPotentiallyEvaluated())
5110 Info.FFDiag(E, diag::note_constexpr_typeid_polymorphic)
5111 << E->getExprOperand()->getType()
5112 << E->getExprOperand()->getSourceRange();
5116 bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
5120 bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
5121 // Handle static data members.
5122 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
5123 VisitIgnoredBaseExpression(E->getBase());
5124 return VisitVarDecl(E, VD);
5127 // Handle static member functions.
5128 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
5129 if (MD->isStatic()) {
5130 VisitIgnoredBaseExpression(E->getBase());
5135 // Handle non-static data members.
5136 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
5139 bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
5140 // FIXME: Deal with vectors as array subscript bases.
5141 if (E->getBase()->getType()->isVectorType())
5144 if (!EvaluatePointer(E->getBase(), Result, Info))
5148 if (!EvaluateInteger(E->getIdx(), Index, Info))
5151 return HandleLValueArrayAdjustment(Info, E, Result, E->getType(),
5152 getExtValue(Index));
5155 bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
5156 return EvaluatePointer(E->getSubExpr(), Result, Info);
5159 bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
5160 if (!Visit(E->getSubExpr()))
5162 // __real is a no-op on scalar lvalues.
5163 if (E->getSubExpr()->getType()->isAnyComplexType())
5164 HandleLValueComplexElement(Info, E, Result, E->getType(), false);
5168 bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
5169 assert(E->getSubExpr()->getType()->isAnyComplexType() &&
5170 "lvalue __imag__ on scalar?");
5171 if (!Visit(E->getSubExpr()))
5173 HandleLValueComplexElement(Info, E, Result, E->getType(), true);
5177 bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
5178 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5181 if (!this->Visit(UO->getSubExpr()))
5184 return handleIncDec(
5185 this->Info, UO, Result, UO->getSubExpr()->getType(),
5186 UO->isIncrementOp(), nullptr);
5189 bool LValueExprEvaluator::VisitCompoundAssignOperator(
5190 const CompoundAssignOperator *CAO) {
5191 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5196 // The overall lvalue result is the result of evaluating the LHS.
5197 if (!this->Visit(CAO->getLHS())) {
5198 if (Info.noteFailure())
5199 Evaluate(RHS, this->Info, CAO->getRHS());
5203 if (!Evaluate(RHS, this->Info, CAO->getRHS()))
5206 return handleCompoundAssignment(
5208 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
5209 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS);
5212 bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
5213 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
5218 if (!this->Visit(E->getLHS())) {
5219 if (Info.noteFailure())
5220 Evaluate(NewVal, this->Info, E->getRHS());
5224 if (!Evaluate(NewVal, this->Info, E->getRHS()))
5227 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
5231 //===----------------------------------------------------------------------===//
5232 // Pointer Evaluation
5233 //===----------------------------------------------------------------------===//
5235 /// \brief Attempts to compute the number of bytes available at the pointer
5236 /// returned by a function with the alloc_size attribute. Returns true if we
5237 /// were successful. Places an unsigned number into `Result`.
5239 /// This expects the given CallExpr to be a call to a function with an
5240 /// alloc_size attribute.
5241 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
5242 const CallExpr *Call,
5243 llvm::APInt &Result) {
5244 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
5246 // alloc_size args are 1-indexed, 0 means not present.
5247 assert(AllocSize && AllocSize->getElemSizeParam() != 0);
5248 unsigned SizeArgNo = AllocSize->getElemSizeParam() - 1;
5249 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
5250 if (Call->getNumArgs() <= SizeArgNo)
5253 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
5254 if (!E->EvaluateAsInt(Into, Ctx, Expr::SE_AllowSideEffects))
5256 if (Into.isNegative() || !Into.isIntN(BitsInSizeT))
5258 Into = Into.zextOrSelf(BitsInSizeT);
5263 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
5266 if (!AllocSize->getNumElemsParam()) {
5267 Result = std::move(SizeOfElem);
5271 APSInt NumberOfElems;
5272 // Argument numbers start at 1
5273 unsigned NumArgNo = AllocSize->getNumElemsParam() - 1;
5274 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
5278 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow);
5282 Result = std::move(BytesAvailable);
5286 /// \brief Convenience function. LVal's base must be a call to an alloc_size
5288 static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
5290 llvm::APInt &Result) {
5291 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
5292 "Can't get the size of a non alloc_size function");
5293 const auto *Base = LVal.getLValueBase().get<const Expr *>();
5294 const CallExpr *CE = tryUnwrapAllocSizeCall(Base);
5295 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result);
5298 /// \brief Attempts to evaluate the given LValueBase as the result of a call to
5299 /// a function with the alloc_size attribute. If it was possible to do so, this
5300 /// function will return true, make Result's Base point to said function call,
5301 /// and mark Result's Base as invalid.
5302 static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
5304 if (!Info.allowInvalidBaseExpr() || Base.isNull())
5307 // Because we do no form of static analysis, we only support const variables.
5309 // Additionally, we can't support parameters, nor can we support static
5310 // variables (in the latter case, use-before-assign isn't UB; in the former,
5311 // we have no clue what they'll be assigned to).
5313 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>());
5314 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
5317 const Expr *Init = VD->getAnyInitializer();
5321 const Expr *E = Init->IgnoreParens();
5322 if (!tryUnwrapAllocSizeCall(E))
5325 // Store E instead of E unwrapped so that the type of the LValue's base is
5326 // what the user wanted.
5327 Result.setInvalid(E);
5329 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
5330 Result.addUnsizedArray(Info, Pointee);
5335 class PointerExprEvaluator
5336 : public ExprEvaluatorBase<PointerExprEvaluator> {
5339 bool Success(const Expr *E) {
5344 bool visitNonBuiltinCallExpr(const CallExpr *E);
5347 PointerExprEvaluator(EvalInfo &info, LValue &Result)
5348 : ExprEvaluatorBaseTy(info), Result(Result) {}
5350 bool Success(const APValue &V, const Expr *E) {
5351 Result.setFrom(Info.Ctx, V);
5354 bool ZeroInitialization(const Expr *E) {
5355 auto Offset = Info.Ctx.getTargetNullPointerValue(E->getType());
5356 Result.set((Expr*)nullptr, 0, false, true, Offset);
5360 bool VisitBinaryOperator(const BinaryOperator *E);
5361 bool VisitCastExpr(const CastExpr* E);
5362 bool VisitUnaryAddrOf(const UnaryOperator *E);
5363 bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
5364 { return Success(E); }
5365 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E)
5366 { return Success(E); }
5367 bool VisitAddrLabelExpr(const AddrLabelExpr *E)
5368 { return Success(E); }
5369 bool VisitCallExpr(const CallExpr *E);
5370 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
5371 bool VisitBlockExpr(const BlockExpr *E) {
5372 if (!E->getBlockDecl()->hasCaptures())
5376 bool VisitCXXThisExpr(const CXXThisExpr *E) {
5377 // Can't look at 'this' when checking a potential constant expression.
5378 if (Info.checkingPotentialConstantExpression())
5380 if (!Info.CurrentCall->This) {
5381 if (Info.getLangOpts().CPlusPlus11)
5382 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
5387 Result = *Info.CurrentCall->This;
5391 // FIXME: Missing: @protocol, @selector
5393 } // end anonymous namespace
5395 static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info) {
5396 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
5397 return PointerExprEvaluator(Info, Result).Visit(E);
5400 bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
5401 if (E->getOpcode() != BO_Add &&
5402 E->getOpcode() != BO_Sub)
5403 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
5405 const Expr *PExp = E->getLHS();
5406 const Expr *IExp = E->getRHS();
5407 if (IExp->getType()->isPointerType())
5408 std::swap(PExp, IExp);
5410 bool EvalPtrOK = EvaluatePointer(PExp, Result, Info);
5411 if (!EvalPtrOK && !Info.noteFailure())
5414 llvm::APSInt Offset;
5415 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
5418 int64_t AdditionalOffset = getExtValue(Offset);
5419 if (E->getOpcode() == BO_Sub)
5420 AdditionalOffset = -AdditionalOffset;
5422 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
5423 return HandleLValueArrayAdjustment(Info, E, Result, Pointee,
5427 bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
5428 return EvaluateLValue(E->getSubExpr(), Result, Info);
5431 bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
5432 const Expr* SubExpr = E->getSubExpr();
5434 switch (E->getCastKind()) {
5439 case CK_CPointerToObjCPointerCast:
5440 case CK_BlockPointerToObjCPointerCast:
5441 case CK_AnyPointerToBlockPointerCast:
5442 case CK_AddressSpaceConversion:
5443 if (!Visit(SubExpr))
5445 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
5446 // permitted in constant expressions in C++11. Bitcasts from cv void* are
5447 // also static_casts, but we disallow them as a resolution to DR1312.
5448 if (!E->getType()->isVoidPointerType()) {
5449 Result.Designator.setInvalid();
5450 if (SubExpr->getType()->isVoidPointerType())
5451 CCEDiag(E, diag::note_constexpr_invalid_cast)
5452 << 3 << SubExpr->getType();
5454 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5456 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
5457 ZeroInitialization(E);
5460 case CK_DerivedToBase:
5461 case CK_UncheckedDerivedToBase:
5462 if (!EvaluatePointer(E->getSubExpr(), Result, Info))
5464 if (!Result.Base && Result.Offset.isZero())
5467 // Now figure out the necessary offset to add to the base LV to get from
5468 // the derived class to the base class.
5469 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()->
5470 castAs<PointerType>()->getPointeeType(),
5473 case CK_BaseToDerived:
5474 if (!Visit(E->getSubExpr()))
5476 if (!Result.Base && Result.Offset.isZero())
5478 return HandleBaseToDerivedCast(Info, E, Result);
5480 case CK_NullToPointer:
5481 VisitIgnoredValue(E->getSubExpr());
5482 return ZeroInitialization(E);
5484 case CK_IntegralToPointer: {
5485 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
5488 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
5491 if (Value.isInt()) {
5492 unsigned Size = Info.Ctx.getTypeSize(E->getType());
5493 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
5494 Result.Base = (Expr*)nullptr;
5495 Result.InvalidBase = false;
5496 Result.Offset = CharUnits::fromQuantity(N);
5497 Result.CallIndex = 0;
5498 Result.Designator.setInvalid();
5499 Result.IsNullPtr = false;
5502 // Cast is of an lvalue, no need to change value.
5503 Result.setFrom(Info.Ctx, Value);
5507 case CK_ArrayToPointerDecay:
5508 if (SubExpr->isGLValue()) {
5509 if (!EvaluateLValue(SubExpr, Result, Info))
5512 Result.set(SubExpr, Info.CurrentCall->Index);
5513 if (!EvaluateInPlace(Info.CurrentCall->createTemporary(SubExpr, false),
5514 Info, Result, SubExpr))
5517 // The result is a pointer to the first element of the array.
5518 if (const ConstantArrayType *CAT
5519 = Info.Ctx.getAsConstantArrayType(SubExpr->getType()))
5520 Result.addArray(Info, E, CAT);
5522 Result.Designator.setInvalid();
5525 case CK_FunctionToPointerDecay:
5526 return EvaluateLValue(SubExpr, Result, Info);
5528 case CK_LValueToRValue: {
5530 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
5534 // Note, we use the subexpression's type in order to retain cv-qualifiers.
5535 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
5537 return evaluateLValueAsAllocSize(Info, LVal.Base, Result);
5538 return Success(RVal, E);
5542 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5545 static CharUnits GetAlignOfType(EvalInfo &Info, QualType T) {
5546 // C++ [expr.alignof]p3:
5547 // When alignof is applied to a reference type, the result is the
5548 // alignment of the referenced type.
5549 if (const ReferenceType *Ref = T->getAs<ReferenceType>())
5550 T = Ref->getPointeeType();
5552 // __alignof is defined to return the preferred alignment.
5553 return Info.Ctx.toCharUnitsFromBits(
5554 Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
5557 static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E) {
5558 E = E->IgnoreParens();
5560 // The kinds of expressions that we have special-case logic here for
5561 // should be kept up to date with the special checks for those
5562 // expressions in Sema.
5564 // alignof decl is always accepted, even if it doesn't make sense: we default
5565 // to 1 in those cases.
5566 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
5567 return Info.Ctx.getDeclAlign(DRE->getDecl(),
5568 /*RefAsPointee*/true);
5570 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
5571 return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
5572 /*RefAsPointee*/true);
5574 return GetAlignOfType(Info, E->getType());
5577 // To be clear: this happily visits unsupported builtins. Better name welcomed.
5578 bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
5579 if (ExprEvaluatorBaseTy::VisitCallExpr(E))
5582 if (!(Info.allowInvalidBaseExpr() && getAllocSizeAttr(E)))
5585 Result.setInvalid(E);
5586 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
5587 Result.addUnsizedArray(Info, PointeeTy);
5591 bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
5592 if (IsStringLiteralCall(E))
5595 if (unsigned BuiltinOp = E->getBuiltinCallee())
5596 return VisitBuiltinCallExpr(E, BuiltinOp);
5598 return visitNonBuiltinCallExpr(E);
5601 bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
5602 unsigned BuiltinOp) {
5603 switch (BuiltinOp) {
5604 case Builtin::BI__builtin_addressof:
5605 return EvaluateLValue(E->getArg(0), Result, Info);
5606 case Builtin::BI__builtin_assume_aligned: {
5607 // We need to be very careful here because: if the pointer does not have the
5608 // asserted alignment, then the behavior is undefined, and undefined
5609 // behavior is non-constant.
5610 if (!EvaluatePointer(E->getArg(0), Result, Info))
5613 LValue OffsetResult(Result);
5615 if (!EvaluateInteger(E->getArg(1), Alignment, Info))
5617 CharUnits Align = CharUnits::fromQuantity(getExtValue(Alignment));
5619 if (E->getNumArgs() > 2) {
5621 if (!EvaluateInteger(E->getArg(2), Offset, Info))
5624 int64_t AdditionalOffset = -getExtValue(Offset);
5625 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
5628 // If there is a base object, then it must have the correct alignment.
5629 if (OffsetResult.Base) {
5630 CharUnits BaseAlignment;
5631 if (const ValueDecl *VD =
5632 OffsetResult.Base.dyn_cast<const ValueDecl*>()) {
5633 BaseAlignment = Info.Ctx.getDeclAlign(VD);
5636 GetAlignOfExpr(Info, OffsetResult.Base.get<const Expr*>());
5639 if (BaseAlignment < Align) {
5640 Result.Designator.setInvalid();
5641 // FIXME: Quantities here cast to integers because the plural modifier
5642 // does not work on APSInts yet.
5643 CCEDiag(E->getArg(0),
5644 diag::note_constexpr_baa_insufficient_alignment) << 0
5645 << (int) BaseAlignment.getQuantity()
5646 << (unsigned) getExtValue(Alignment);
5651 // The offset must also have the correct alignment.
5652 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
5653 Result.Designator.setInvalid();
5654 APSInt Offset(64, false);
5655 Offset = OffsetResult.Offset.getQuantity();
5657 if (OffsetResult.Base)
5658 CCEDiag(E->getArg(0),
5659 diag::note_constexpr_baa_insufficient_alignment) << 1
5660 << (int) getExtValue(Offset) << (unsigned) getExtValue(Alignment);
5662 CCEDiag(E->getArg(0),
5663 diag::note_constexpr_baa_value_insufficient_alignment)
5664 << Offset << (unsigned) getExtValue(Alignment);
5672 case Builtin::BIstrchr:
5673 case Builtin::BIwcschr:
5674 case Builtin::BImemchr:
5675 case Builtin::BIwmemchr:
5676 if (Info.getLangOpts().CPlusPlus11)
5677 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
5678 << /*isConstexpr*/0 << /*isConstructor*/0
5679 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
5681 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
5683 case Builtin::BI__builtin_strchr:
5684 case Builtin::BI__builtin_wcschr:
5685 case Builtin::BI__builtin_memchr:
5686 case Builtin::BI__builtin_char_memchr:
5687 case Builtin::BI__builtin_wmemchr: {
5688 if (!Visit(E->getArg(0)))
5691 if (!EvaluateInteger(E->getArg(1), Desired, Info))
5693 uint64_t MaxLength = uint64_t(-1);
5694 if (BuiltinOp != Builtin::BIstrchr &&
5695 BuiltinOp != Builtin::BIwcschr &&
5696 BuiltinOp != Builtin::BI__builtin_strchr &&
5697 BuiltinOp != Builtin::BI__builtin_wcschr) {
5699 if (!EvaluateInteger(E->getArg(2), N, Info))
5701 MaxLength = N.getExtValue();
5704 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
5706 // Figure out what value we're actually looking for (after converting to
5707 // the corresponding unsigned type if necessary).
5708 uint64_t DesiredVal;
5709 bool StopAtNull = false;
5710 switch (BuiltinOp) {
5711 case Builtin::BIstrchr:
5712 case Builtin::BI__builtin_strchr:
5713 // strchr compares directly to the passed integer, and therefore
5714 // always fails if given an int that is not a char.
5715 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy,
5716 E->getArg(1)->getType(),
5719 return ZeroInitialization(E);
5722 case Builtin::BImemchr:
5723 case Builtin::BI__builtin_memchr:
5724 case Builtin::BI__builtin_char_memchr:
5725 // memchr compares by converting both sides to unsigned char. That's also
5726 // correct for strchr if we get this far (to cope with plain char being
5727 // unsigned in the strchr case).
5728 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue();
5731 case Builtin::BIwcschr:
5732 case Builtin::BI__builtin_wcschr:
5735 case Builtin::BIwmemchr:
5736 case Builtin::BI__builtin_wmemchr:
5737 // wcschr and wmemchr are given a wchar_t to look for. Just use it.
5738 DesiredVal = Desired.getZExtValue();
5742 for (; MaxLength; --MaxLength) {
5744 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
5747 if (Char.getInt().getZExtValue() == DesiredVal)
5749 if (StopAtNull && !Char.getInt())
5751 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
5754 // Not found: return nullptr.
5755 return ZeroInitialization(E);
5759 return visitNonBuiltinCallExpr(E);
5763 //===----------------------------------------------------------------------===//
5764 // Member Pointer Evaluation
5765 //===----------------------------------------------------------------------===//
5768 class MemberPointerExprEvaluator
5769 : public ExprEvaluatorBase<MemberPointerExprEvaluator> {
5772 bool Success(const ValueDecl *D) {
5773 Result = MemberPtr(D);
5778 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
5779 : ExprEvaluatorBaseTy(Info), Result(Result) {}
5781 bool Success(const APValue &V, const Expr *E) {
5785 bool ZeroInitialization(const Expr *E) {
5786 return Success((const ValueDecl*)nullptr);
5789 bool VisitCastExpr(const CastExpr *E);
5790 bool VisitUnaryAddrOf(const UnaryOperator *E);
5792 } // end anonymous namespace
5794 static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
5796 assert(E->isRValue() && E->getType()->isMemberPointerType());
5797 return MemberPointerExprEvaluator(Info, Result).Visit(E);
5800 bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
5801 switch (E->getCastKind()) {
5803 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5805 case CK_NullToMemberPointer:
5806 VisitIgnoredValue(E->getSubExpr());
5807 return ZeroInitialization(E);
5809 case CK_BaseToDerivedMemberPointer: {
5810 if (!Visit(E->getSubExpr()))
5812 if (E->path_empty())
5814 // Base-to-derived member pointer casts store the path in derived-to-base
5815 // order, so iterate backwards. The CXXBaseSpecifier also provides us with
5816 // the wrong end of the derived->base arc, so stagger the path by one class.
5817 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
5818 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
5819 PathI != PathE; ++PathI) {
5820 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
5821 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
5822 if (!Result.castToDerived(Derived))
5825 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
5826 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
5831 case CK_DerivedToBaseMemberPointer:
5832 if (!Visit(E->getSubExpr()))
5834 for (CastExpr::path_const_iterator PathI = E->path_begin(),
5835 PathE = E->path_end(); PathI != PathE; ++PathI) {
5836 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
5837 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
5838 if (!Result.castToBase(Base))
5845 bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
5846 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
5847 // member can be formed.
5848 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
5851 //===----------------------------------------------------------------------===//
5852 // Record Evaluation
5853 //===----------------------------------------------------------------------===//
5856 class RecordExprEvaluator
5857 : public ExprEvaluatorBase<RecordExprEvaluator> {
5862 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
5863 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
5865 bool Success(const APValue &V, const Expr *E) {
5869 bool ZeroInitialization(const Expr *E) {
5870 return ZeroInitialization(E, E->getType());
5872 bool ZeroInitialization(const Expr *E, QualType T);
5874 bool VisitCallExpr(const CallExpr *E) {
5875 return handleCallExpr(E, Result, &This);
5877 bool VisitCastExpr(const CastExpr *E);
5878 bool VisitInitListExpr(const InitListExpr *E);
5879 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
5880 return VisitCXXConstructExpr(E, E->getType());
5882 bool VisitLambdaExpr(const LambdaExpr *E);
5883 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
5884 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
5885 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
5889 /// Perform zero-initialization on an object of non-union class type.
5890 /// C++11 [dcl.init]p5:
5891 /// To zero-initialize an object or reference of type T means:
5893 /// -- if T is a (possibly cv-qualified) non-union class type,
5894 /// each non-static data member and each base-class subobject is
5895 /// zero-initialized
5896 static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
5897 const RecordDecl *RD,
5898 const LValue &This, APValue &Result) {
5899 assert(!RD->isUnion() && "Expected non-union class type");
5900 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
5901 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
5902 std::distance(RD->field_begin(), RD->field_end()));
5904 if (RD->isInvalidDecl()) return false;
5905 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
5909 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
5910 End = CD->bases_end(); I != End; ++I, ++Index) {
5911 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
5912 LValue Subobject = This;
5913 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout))
5915 if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
5916 Result.getStructBase(Index)))
5921 for (const auto *I : RD->fields()) {
5922 // -- if T is a reference type, no initialization is performed.
5923 if (I->getType()->isReferenceType())
5926 LValue Subobject = This;
5927 if (!HandleLValueMember(Info, E, Subobject, I, &Layout))
5930 ImplicitValueInitExpr VIE(I->getType());
5931 if (!EvaluateInPlace(
5932 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE))
5939 bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
5940 const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
5941 if (RD->isInvalidDecl()) return false;
5942 if (RD->isUnion()) {
5943 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
5944 // object's first non-static named data member is zero-initialized
5945 RecordDecl::field_iterator I = RD->field_begin();
5946 if (I == RD->field_end()) {
5947 Result = APValue((const FieldDecl*)nullptr);
5951 LValue Subobject = This;
5952 if (!HandleLValueMember(Info, E, Subobject, *I))
5954 Result = APValue(*I);
5955 ImplicitValueInitExpr VIE(I->getType());
5956 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
5959 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
5960 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
5964 return HandleClassZeroInitialization(Info, E, RD, This, Result);
5967 bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
5968 switch (E->getCastKind()) {
5970 return ExprEvaluatorBaseTy::VisitCastExpr(E);
5972 case CK_ConstructorConversion:
5973 return Visit(E->getSubExpr());
5975 case CK_DerivedToBase:
5976 case CK_UncheckedDerivedToBase: {
5977 APValue DerivedObject;
5978 if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
5980 if (!DerivedObject.isStruct())
5981 return Error(E->getSubExpr());
5983 // Derived-to-base rvalue conversion: just slice off the derived part.
5984 APValue *Value = &DerivedObject;
5985 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
5986 for (CastExpr::path_const_iterator PathI = E->path_begin(),
5987 PathE = E->path_end(); PathI != PathE; ++PathI) {
5988 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base");
5989 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
5990 Value = &Value->getStructBase(getBaseIndex(RD, Base));
5999 bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6000 if (E->isTransparent())
6001 return Visit(E->getInit(0));
6003 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
6004 if (RD->isInvalidDecl()) return false;
6005 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6007 if (RD->isUnion()) {
6008 const FieldDecl *Field = E->getInitializedFieldInUnion();
6009 Result = APValue(Field);
6013 // If the initializer list for a union does not contain any elements, the
6014 // first element of the union is value-initialized.
6015 // FIXME: The element should be initialized from an initializer list.
6016 // Is this difference ever observable for initializer lists which
6018 ImplicitValueInitExpr VIE(Field->getType());
6019 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;
6021 LValue Subobject = This;
6022 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout))
6025 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
6026 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
6027 isa<CXXDefaultInitExpr>(InitExpr));
6029 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr);
6032 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
6033 if (Result.isUninit())
6034 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
6035 std::distance(RD->field_begin(), RD->field_end()));
6036 unsigned ElementNo = 0;
6037 bool Success = true;
6039 // Initialize base classes.
6041 for (const auto &Base : CXXRD->bases()) {
6042 assert(ElementNo < E->getNumInits() && "missing init for base class");
6043 const Expr *Init = E->getInit(ElementNo);
6045 LValue Subobject = This;
6046 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base))
6049 APValue &FieldVal = Result.getStructBase(ElementNo);
6050 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) {
6051 if (!Info.noteFailure())
6059 // Initialize members.
6060 for (const auto *Field : RD->fields()) {
6061 // Anonymous bit-fields are not considered members of the class for
6062 // purposes of aggregate initialization.
6063 if (Field->isUnnamedBitfield())
6066 LValue Subobject = This;
6068 bool HaveInit = ElementNo < E->getNumInits();
6070 // FIXME: Diagnostics here should point to the end of the initializer
6071 // list, not the start.
6072 if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E,
6073 Subobject, Field, &Layout))
6076 // Perform an implicit value-initialization for members beyond the end of
6077 // the initializer list.
6078 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
6079 const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE;
6081 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
6082 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
6083 isa<CXXDefaultInitExpr>(Init));
6085 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
6086 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) ||
6087 (Field->isBitField() && !truncateBitfieldValue(Info, Init,
6088 FieldVal, Field))) {
6089 if (!Info.noteFailure())
6098 bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
6100 // Note that E's type is not necessarily the type of our class here; we might
6101 // be initializing an array element instead.
6102 const CXXConstructorDecl *FD = E->getConstructor();
6103 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
6105 bool ZeroInit = E->requiresZeroInitialization();
6106 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
6107 // If we've already performed zero-initialization, we're already done.
6108 if (!Result.isUninit())
6111 // We can get here in two different ways:
6112 // 1) We're performing value-initialization, and should zero-initialize
6114 // 2) We're performing default-initialization of an object with a trivial
6115 // constexpr default constructor, in which case we should start the
6116 // lifetimes of all the base subobjects (there can be no data member
6117 // subobjects in this case) per [basic.life]p1.
6118 // Either way, ZeroInitialization is appropriate.
6119 return ZeroInitialization(E, T);
6122 const FunctionDecl *Definition = nullptr;
6123 auto Body = FD->getBody(Definition);
6125 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
6128 // Avoid materializing a temporary for an elidable copy/move constructor.
6129 if (E->isElidable() && !ZeroInit)
6130 if (const MaterializeTemporaryExpr *ME
6131 = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0)))
6132 return Visit(ME->GetTemporaryExpr());
6134 if (ZeroInit && !ZeroInitialization(E, T))
6137 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
6138 return HandleConstructorCall(E, This, Args,
6139 cast<CXXConstructorDecl>(Definition), Info,
6143 bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
6144 const CXXInheritedCtorInitExpr *E) {
6145 if (!Info.CurrentCall) {
6146 assert(Info.checkingPotentialConstantExpression());
6150 const CXXConstructorDecl *FD = E->getConstructor();
6151 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
6154 const FunctionDecl *Definition = nullptr;
6155 auto Body = FD->getBody(Definition);
6157 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
6160 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
6161 cast<CXXConstructorDecl>(Definition), Info,
6165 bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
6166 const CXXStdInitializerListExpr *E) {
6167 const ConstantArrayType *ArrayType =
6168 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
6171 if (!EvaluateLValue(E->getSubExpr(), Array, Info))
6174 // Get a pointer to the first element of the array.
6175 Array.addArray(Info, E, ArrayType);
6177 // FIXME: Perform the checks on the field types in SemaInit.
6178 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
6179 RecordDecl::field_iterator Field = Record->field_begin();
6180 if (Field == Record->field_end())
6184 if (!Field->getType()->isPointerType() ||
6185 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
6186 ArrayType->getElementType()))
6189 // FIXME: What if the initializer_list type has base classes, etc?
6190 Result = APValue(APValue::UninitStruct(), 0, 2);
6191 Array.moveInto(Result.getStructField(0));
6193 if (++Field == Record->field_end())
6196 if (Field->getType()->isPointerType() &&
6197 Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
6198 ArrayType->getElementType())) {
6200 if (!HandleLValueArrayAdjustment(Info, E, Array,
6201 ArrayType->getElementType(),
6202 ArrayType->getSize().getZExtValue()))
6204 Array.moveInto(Result.getStructField(1));
6205 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
6207 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize()));
6211 if (++Field != Record->field_end())
6217 bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
6218 const CXXRecordDecl *ClosureClass = E->getLambdaClass();
6219 if (ClosureClass->isInvalidDecl()) return false;
6221 if (Info.checkingPotentialConstantExpression()) return true;
6222 if (E->capture_size()) {
6223 Info.FFDiag(E, diag::note_unimplemented_constexpr_lambda_feature_ast)
6224 << "can not evaluate lambda expressions with captures";
6227 // FIXME: Implement captures.
6228 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, /*NumFields*/0);
6232 static bool EvaluateRecord(const Expr *E, const LValue &This,
6233 APValue &Result, EvalInfo &Info) {
6234 assert(E->isRValue() && E->getType()->isRecordType() &&
6235 "can't evaluate expression as a record rvalue");
6236 return RecordExprEvaluator(Info, This, Result).Visit(E);
6239 //===----------------------------------------------------------------------===//
6240 // Temporary Evaluation
6242 // Temporaries are represented in the AST as rvalues, but generally behave like
6243 // lvalues. The full-object of which the temporary is a subobject is implicitly
6244 // materialized so that a reference can bind to it.
6245 //===----------------------------------------------------------------------===//
6247 class TemporaryExprEvaluator
6248 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
6250 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
6251 LValueExprEvaluatorBaseTy(Info, Result) {}
6253 /// Visit an expression which constructs the value of this temporary.
6254 bool VisitConstructExpr(const Expr *E) {
6255 Result.set(E, Info.CurrentCall->Index);
6256 return EvaluateInPlace(Info.CurrentCall->createTemporary(E, false),
6260 bool VisitCastExpr(const CastExpr *E) {
6261 switch (E->getCastKind()) {
6263 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
6265 case CK_ConstructorConversion:
6266 return VisitConstructExpr(E->getSubExpr());
6269 bool VisitInitListExpr(const InitListExpr *E) {
6270 return VisitConstructExpr(E);
6272 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
6273 return VisitConstructExpr(E);
6275 bool VisitCallExpr(const CallExpr *E) {
6276 return VisitConstructExpr(E);
6278 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
6279 return VisitConstructExpr(E);
6281 bool VisitLambdaExpr(const LambdaExpr *E) {
6282 return VisitConstructExpr(E);
6285 } // end anonymous namespace
6287 /// Evaluate an expression of record type as a temporary.
6288 static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
6289 assert(E->isRValue() && E->getType()->isRecordType());
6290 return TemporaryExprEvaluator(Info, Result).Visit(E);
6293 //===----------------------------------------------------------------------===//
6294 // Vector Evaluation
6295 //===----------------------------------------------------------------------===//
6298 class VectorExprEvaluator
6299 : public ExprEvaluatorBase<VectorExprEvaluator> {
6303 VectorExprEvaluator(EvalInfo &info, APValue &Result)
6304 : ExprEvaluatorBaseTy(info), Result(Result) {}
6306 bool Success(ArrayRef<APValue> V, const Expr *E) {
6307 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements());
6308 // FIXME: remove this APValue copy.
6309 Result = APValue(V.data(), V.size());
6312 bool Success(const APValue &V, const Expr *E) {
6313 assert(V.isVector());
6317 bool ZeroInitialization(const Expr *E);
6319 bool VisitUnaryReal(const UnaryOperator *E)
6320 { return Visit(E->getSubExpr()); }
6321 bool VisitCastExpr(const CastExpr* E);
6322 bool VisitInitListExpr(const InitListExpr *E);
6323 bool VisitUnaryImag(const UnaryOperator *E);
6324 // FIXME: Missing: unary -, unary ~, binary add/sub/mul/div,
6325 // binary comparisons, binary and/or/xor,
6326 // shufflevector, ExtVectorElementExpr
6328 } // end anonymous namespace
6330 static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
6331 assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue");
6332 return VectorExprEvaluator(Info, Result).Visit(E);
6335 bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
6336 const VectorType *VTy = E->getType()->castAs<VectorType>();
6337 unsigned NElts = VTy->getNumElements();
6339 const Expr *SE = E->getSubExpr();
6340 QualType SETy = SE->getType();
6342 switch (E->getCastKind()) {
6343 case CK_VectorSplat: {
6344 APValue Val = APValue();
6345 if (SETy->isIntegerType()) {
6347 if (!EvaluateInteger(SE, IntResult, Info))
6349 Val = APValue(std::move(IntResult));
6350 } else if (SETy->isRealFloatingType()) {
6351 APFloat FloatResult(0.0);
6352 if (!EvaluateFloat(SE, FloatResult, Info))
6354 Val = APValue(std::move(FloatResult));
6359 // Splat and create vector APValue.
6360 SmallVector<APValue, 4> Elts(NElts, Val);
6361 return Success(Elts, E);
6364 // Evaluate the operand into an APInt we can extract from.
6365 llvm::APInt SValInt;
6366 if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
6368 // Extract the elements
6369 QualType EltTy = VTy->getElementType();
6370 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
6371 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
6372 SmallVector<APValue, 4> Elts;
6373 if (EltTy->isRealFloatingType()) {
6374 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
6375 unsigned FloatEltSize = EltSize;
6376 if (&Sem == &APFloat::x87DoubleExtended())
6378 for (unsigned i = 0; i < NElts; i++) {
6381 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
6383 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
6384 Elts.push_back(APValue(APFloat(Sem, Elt)));
6386 } else if (EltTy->isIntegerType()) {
6387 for (unsigned i = 0; i < NElts; i++) {
6390 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
6392 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
6393 Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType())));
6398 return Success(Elts, E);
6401 return ExprEvaluatorBaseTy::VisitCastExpr(E);
6406 VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6407 const VectorType *VT = E->getType()->castAs<VectorType>();
6408 unsigned NumInits = E->getNumInits();
6409 unsigned NumElements = VT->getNumElements();
6411 QualType EltTy = VT->getElementType();
6412 SmallVector<APValue, 4> Elements;
6414 // The number of initializers can be less than the number of
6415 // vector elements. For OpenCL, this can be due to nested vector
6416 // initialization. For GCC compatibility, missing trailing elements
6417 // should be initialized with zeroes.
6418 unsigned CountInits = 0, CountElts = 0;
6419 while (CountElts < NumElements) {
6420 // Handle nested vector initialization.
6421 if (CountInits < NumInits
6422 && E->getInit(CountInits)->getType()->isVectorType()) {
6424 if (!EvaluateVector(E->getInit(CountInits), v, Info))
6426 unsigned vlen = v.getVectorLength();
6427 for (unsigned j = 0; j < vlen; j++)
6428 Elements.push_back(v.getVectorElt(j));
6430 } else if (EltTy->isIntegerType()) {
6431 llvm::APSInt sInt(32);
6432 if (CountInits < NumInits) {
6433 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
6435 } else // trailing integer zero.
6436 sInt = Info.Ctx.MakeIntValue(0, EltTy);
6437 Elements.push_back(APValue(sInt));
6440 llvm::APFloat f(0.0);
6441 if (CountInits < NumInits) {
6442 if (!EvaluateFloat(E->getInit(CountInits), f, Info))
6444 } else // trailing float zero.
6445 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
6446 Elements.push_back(APValue(f));
6451 return Success(Elements, E);
6455 VectorExprEvaluator::ZeroInitialization(const Expr *E) {
6456 const VectorType *VT = E->getType()->getAs<VectorType>();
6457 QualType EltTy = VT->getElementType();
6458 APValue ZeroElement;
6459 if (EltTy->isIntegerType())
6460 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
6463 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
6465 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
6466 return Success(Elements, E);
6469 bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
6470 VisitIgnoredValue(E->getSubExpr());
6471 return ZeroInitialization(E);
6474 //===----------------------------------------------------------------------===//
6476 //===----------------------------------------------------------------------===//
6479 class ArrayExprEvaluator
6480 : public ExprEvaluatorBase<ArrayExprEvaluator> {
6485 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
6486 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
6488 bool Success(const APValue &V, const Expr *E) {
6489 assert((V.isArray() || V.isLValue()) &&
6490 "expected array or string literal");
6495 bool ZeroInitialization(const Expr *E) {
6496 const ConstantArrayType *CAT =
6497 Info.Ctx.getAsConstantArrayType(E->getType());
6501 Result = APValue(APValue::UninitArray(), 0,
6502 CAT->getSize().getZExtValue());
6503 if (!Result.hasArrayFiller()) return true;
6505 // Zero-initialize all elements.
6506 LValue Subobject = This;
6507 Subobject.addArray(Info, E, CAT);
6508 ImplicitValueInitExpr VIE(CAT->getElementType());
6509 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
6512 bool VisitCallExpr(const CallExpr *E) {
6513 return handleCallExpr(E, Result, &This);
6515 bool VisitInitListExpr(const InitListExpr *E);
6516 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
6517 bool VisitCXXConstructExpr(const CXXConstructExpr *E);
6518 bool VisitCXXConstructExpr(const CXXConstructExpr *E,
6519 const LValue &Subobject,
6520 APValue *Value, QualType Type);
6522 } // end anonymous namespace
6524 static bool EvaluateArray(const Expr *E, const LValue &This,
6525 APValue &Result, EvalInfo &Info) {
6526 assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue");
6527 return ArrayExprEvaluator(Info, This, Result).Visit(E);
6530 bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
6531 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType());
6535 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
6536 // an appropriately-typed string literal enclosed in braces.
6537 if (E->isStringLiteralInit()) {
6539 if (!EvaluateLValue(E->getInit(0), LV, Info))
6543 return Success(Val, E);
6546 bool Success = true;
6548 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&
6549 "zero-initialized array shouldn't have any initialized elts");
6551 if (Result.isArray() && Result.hasArrayFiller())
6552 Filler = Result.getArrayFiller();
6554 unsigned NumEltsToInit = E->getNumInits();
6555 unsigned NumElts = CAT->getSize().getZExtValue();
6556 const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr;
6558 // If the initializer might depend on the array index, run it for each
6559 // array element. For now, just whitelist non-class value-initialization.
6560 if (NumEltsToInit != NumElts && !isa<ImplicitValueInitExpr>(FillerExpr))
6561 NumEltsToInit = NumElts;
6563 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
6565 // If the array was previously zero-initialized, preserve the
6566 // zero-initialized values.
6567 if (!Filler.isUninit()) {
6568 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
6569 Result.getArrayInitializedElt(I) = Filler;
6570 if (Result.hasArrayFiller())
6571 Result.getArrayFiller() = Filler;
6574 LValue Subobject = This;
6575 Subobject.addArray(Info, E, CAT);
6576 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
6578 Index < E->getNumInits() ? E->getInit(Index) : FillerExpr;
6579 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
6580 Info, Subobject, Init) ||
6581 !HandleLValueArrayAdjustment(Info, Init, Subobject,
6582 CAT->getElementType(), 1)) {
6583 if (!Info.noteFailure())
6589 if (!Result.hasArrayFiller())
6592 // If we get here, we have a trivial filler, which we can just evaluate
6593 // once and splat over the rest of the array elements.
6594 assert(FillerExpr && "no array filler for incomplete init list");
6595 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject,
6596 FillerExpr) && Success;
6599 bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
6600 if (E->getCommonExpr() &&
6601 !Evaluate(Info.CurrentCall->createTemporary(E->getCommonExpr(), false),
6602 Info, E->getCommonExpr()->getSourceExpr()))
6605 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());
6607 uint64_t Elements = CAT->getSize().getZExtValue();
6608 Result = APValue(APValue::UninitArray(), Elements, Elements);
6610 LValue Subobject = This;
6611 Subobject.addArray(Info, E, CAT);
6613 bool Success = true;
6614 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
6615 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
6616 Info, Subobject, E->getSubExpr()) ||
6617 !HandleLValueArrayAdjustment(Info, E, Subobject,
6618 CAT->getElementType(), 1)) {
6619 if (!Info.noteFailure())
6628 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
6629 return VisitCXXConstructExpr(E, This, &Result, E->getType());
6632 bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
6633 const LValue &Subobject,
6636 bool HadZeroInit = !Value->isUninit();
6638 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
6639 unsigned N = CAT->getSize().getZExtValue();
6641 // Preserve the array filler if we had prior zero-initialization.
6643 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
6646 *Value = APValue(APValue::UninitArray(), N, N);
6649 for (unsigned I = 0; I != N; ++I)
6650 Value->getArrayInitializedElt(I) = Filler;
6652 // Initialize the elements.
6653 LValue ArrayElt = Subobject;
6654 ArrayElt.addArray(Info, E, CAT);
6655 for (unsigned I = 0; I != N; ++I)
6656 if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I),
6657 CAT->getElementType()) ||
6658 !HandleLValueArrayAdjustment(Info, E, ArrayElt,
6659 CAT->getElementType(), 1))
6665 if (!Type->isRecordType())
6668 return RecordExprEvaluator(Info, Subobject, *Value)
6669 .VisitCXXConstructExpr(E, Type);
6672 //===----------------------------------------------------------------------===//
6673 // Integer Evaluation
6675 // As a GNU extension, we support casting pointers to sufficiently-wide integer
6676 // types and back in constant folding. Integer values are thus represented
6677 // either as an integer-valued APValue, or as an lvalue-valued APValue.
6678 //===----------------------------------------------------------------------===//
6681 class IntExprEvaluator
6682 : public ExprEvaluatorBase<IntExprEvaluator> {
6685 IntExprEvaluator(EvalInfo &info, APValue &result)
6686 : ExprEvaluatorBaseTy(info), Result(result) {}
6688 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
6689 assert(E->getType()->isIntegralOrEnumerationType() &&
6690 "Invalid evaluation result.");
6691 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
6692 "Invalid evaluation result.");
6693 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
6694 "Invalid evaluation result.");
6695 Result = APValue(SI);
6698 bool Success(const llvm::APSInt &SI, const Expr *E) {
6699 return Success(SI, E, Result);
6702 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
6703 assert(E->getType()->isIntegralOrEnumerationType() &&
6704 "Invalid evaluation result.");
6705 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
6706 "Invalid evaluation result.");
6707 Result = APValue(APSInt(I));
6708 Result.getInt().setIsUnsigned(
6709 E->getType()->isUnsignedIntegerOrEnumerationType());
6712 bool Success(const llvm::APInt &I, const Expr *E) {
6713 return Success(I, E, Result);
6716 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
6717 assert(E->getType()->isIntegralOrEnumerationType() &&
6718 "Invalid evaluation result.");
6719 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
6722 bool Success(uint64_t Value, const Expr *E) {
6723 return Success(Value, E, Result);
6726 bool Success(CharUnits Size, const Expr *E) {
6727 return Success(Size.getQuantity(), E);
6730 bool Success(const APValue &V, const Expr *E) {
6731 if (V.isLValue() || V.isAddrLabelDiff()) {
6735 return Success(V.getInt(), E);
6738 bool ZeroInitialization(const Expr *E) { return Success(0, E); }
6740 //===--------------------------------------------------------------------===//
6742 //===--------------------------------------------------------------------===//
6744 bool VisitIntegerLiteral(const IntegerLiteral *E) {
6745 return Success(E->getValue(), E);
6747 bool VisitCharacterLiteral(const CharacterLiteral *E) {
6748 return Success(E->getValue(), E);
6751 bool CheckReferencedDecl(const Expr *E, const Decl *D);
6752 bool VisitDeclRefExpr(const DeclRefExpr *E) {
6753 if (CheckReferencedDecl(E, E->getDecl()))
6756 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
6758 bool VisitMemberExpr(const MemberExpr *E) {
6759 if (CheckReferencedDecl(E, E->getMemberDecl())) {
6760 VisitIgnoredBaseExpression(E->getBase());
6764 return ExprEvaluatorBaseTy::VisitMemberExpr(E);
6767 bool VisitCallExpr(const CallExpr *E);
6768 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
6769 bool VisitBinaryOperator(const BinaryOperator *E);
6770 bool VisitOffsetOfExpr(const OffsetOfExpr *E);
6771 bool VisitUnaryOperator(const UnaryOperator *E);
6773 bool VisitCastExpr(const CastExpr* E);
6774 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
6776 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
6777 return Success(E->getValue(), E);
6780 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
6781 return Success(E->getValue(), E);
6784 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
6785 if (Info.ArrayInitIndex == uint64_t(-1)) {
6786 // We were asked to evaluate this subexpression independent of the
6787 // enclosing ArrayInitLoopExpr. We can't do that.
6791 return Success(Info.ArrayInitIndex, E);
6794 // Note, GNU defines __null as an integer, not a pointer.
6795 bool VisitGNUNullExpr(const GNUNullExpr *E) {
6796 return ZeroInitialization(E);
6799 bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
6800 return Success(E->getValue(), E);
6803 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
6804 return Success(E->getValue(), E);
6807 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
6808 return Success(E->getValue(), E);
6811 bool VisitUnaryReal(const UnaryOperator *E);
6812 bool VisitUnaryImag(const UnaryOperator *E);
6814 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
6815 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
6817 // FIXME: Missing: array subscript of vector, member of vector
6819 } // end anonymous namespace
6821 /// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
6822 /// produce either the integer value or a pointer.
6824 /// GCC has a heinous extension which folds casts between pointer types and
6825 /// pointer-sized integral types. We support this by allowing the evaluation of
6826 /// an integer rvalue to produce a pointer (represented as an lvalue) instead.
6827 /// Some simple arithmetic on such values is supported (they are treated much
6829 static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
6831 assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType());
6832 return IntExprEvaluator(Info, Result).Visit(E);
6835 static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
6837 if (!EvaluateIntegerOrLValue(E, Val, Info))
6840 // FIXME: It would be better to produce the diagnostic for casting
6841 // a pointer to an integer.
6842 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
6845 Result = Val.getInt();
6849 /// Check whether the given declaration can be directly converted to an integral
6850 /// rvalue. If not, no diagnostic is produced; there are other things we can
6852 bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
6853 // Enums are integer constant exprs.
6854 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
6855 // Check for signedness/width mismatches between E type and ECD value.
6856 bool SameSign = (ECD->getInitVal().isSigned()
6857 == E->getType()->isSignedIntegerOrEnumerationType());
6858 bool SameWidth = (ECD->getInitVal().getBitWidth()
6859 == Info.Ctx.getIntWidth(E->getType()));
6860 if (SameSign && SameWidth)
6861 return Success(ECD->getInitVal(), E);
6863 // Get rid of mismatch (otherwise Success assertions will fail)
6864 // by computing a new value matching the type of E.
6865 llvm::APSInt Val = ECD->getInitVal();
6867 Val.setIsSigned(!ECD->getInitVal().isSigned());
6869 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
6870 return Success(Val, E);
6876 /// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
6878 static int EvaluateBuiltinClassifyType(const CallExpr *E,
6879 const LangOptions &LangOpts) {
6880 // The following enum mimics the values returned by GCC.
6881 // FIXME: Does GCC differ between lvalue and rvalue references here?
6882 enum gcc_type_class {
6884 void_type_class, integer_type_class, char_type_class,
6885 enumeral_type_class, boolean_type_class,
6886 pointer_type_class, reference_type_class, offset_type_class,
6887 real_type_class, complex_type_class,
6888 function_type_class, method_type_class,
6889 record_type_class, union_type_class,
6890 array_type_class, string_type_class,
6894 // If no argument was supplied, default to "no_type_class". This isn't
6895 // ideal, however it is what gcc does.
6896 if (E->getNumArgs() == 0)
6897 return no_type_class;
6899 QualType CanTy = E->getArg(0)->getType().getCanonicalType();
6900 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy);
6902 switch (CanTy->getTypeClass()) {
6903 #define TYPE(ID, BASE)
6904 #define DEPENDENT_TYPE(ID, BASE) case Type::ID:
6905 #define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
6906 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
6907 #include "clang/AST/TypeNodes.def"
6908 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
6911 switch (BT->getKind()) {
6912 #define BUILTIN_TYPE(ID, SINGLETON_ID)
6913 #define SIGNED_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: return integer_type_class;
6914 #define FLOATING_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: return real_type_class;
6915 #define PLACEHOLDER_TYPE(ID, SINGLETON_ID) case BuiltinType::ID: break;
6916 #include "clang/AST/BuiltinTypes.def"
6917 case BuiltinType::Void:
6918 return void_type_class;
6920 case BuiltinType::Bool:
6921 return boolean_type_class;
6923 case BuiltinType::Char_U: // gcc doesn't appear to use char_type_class
6924 case BuiltinType::UChar:
6925 case BuiltinType::UShort:
6926 case BuiltinType::UInt:
6927 case BuiltinType::ULong:
6928 case BuiltinType::ULongLong:
6929 case BuiltinType::UInt128:
6930 return integer_type_class;
6932 case BuiltinType::NullPtr:
6933 return pointer_type_class;
6935 case BuiltinType::WChar_U:
6936 case BuiltinType::Char16:
6937 case BuiltinType::Char32:
6938 case BuiltinType::ObjCId:
6939 case BuiltinType::ObjCClass:
6940 case BuiltinType::ObjCSel:
6941 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
6942 case BuiltinType::Id:
6943 #include "clang/Basic/OpenCLImageTypes.def"
6944 case BuiltinType::OCLSampler:
6945 case BuiltinType::OCLEvent:
6946 case BuiltinType::OCLClkEvent:
6947 case BuiltinType::OCLQueue:
6948 case BuiltinType::OCLNDRange:
6949 case BuiltinType::OCLReserveID:
6950 case BuiltinType::Dependent:
6951 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
6955 return LangOpts.CPlusPlus ? enumeral_type_class : integer_type_class;
6959 return pointer_type_class;
6962 case Type::MemberPointer:
6963 if (CanTy->isMemberDataPointerType())
6964 return offset_type_class;
6966 // We expect member pointers to be either data or function pointers,
6968 assert(CanTy->isMemberFunctionPointerType());
6969 return method_type_class;
6973 return complex_type_class;
6975 case Type::FunctionNoProto:
6976 case Type::FunctionProto:
6977 return LangOpts.CPlusPlus ? function_type_class : pointer_type_class;
6980 if (const RecordType *RT = CanTy->getAs<RecordType>()) {
6981 switch (RT->getDecl()->getTagKind()) {
6982 case TagTypeKind::TTK_Struct:
6983 case TagTypeKind::TTK_Class:
6984 case TagTypeKind::TTK_Interface:
6985 return record_type_class;
6987 case TagTypeKind::TTK_Enum:
6988 return LangOpts.CPlusPlus ? enumeral_type_class : integer_type_class;
6990 case TagTypeKind::TTK_Union:
6991 return union_type_class;
6994 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
6996 case Type::ConstantArray:
6997 case Type::VariableArray:
6998 case Type::IncompleteArray:
6999 return LangOpts.CPlusPlus ? array_type_class : pointer_type_class;
7001 case Type::BlockPointer:
7002 case Type::LValueReference:
7003 case Type::RValueReference:
7005 case Type::ExtVector:
7007 case Type::ObjCObject:
7008 case Type::ObjCInterface:
7009 case Type::ObjCObjectPointer:
7012 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7015 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type");
7018 /// EvaluateBuiltinConstantPForLValue - Determine the result of
7019 /// __builtin_constant_p when applied to the given lvalue.
7021 /// An lvalue is only "constant" if it is a pointer or reference to the first
7022 /// character of a string literal.
7023 template<typename LValue>
7024 static bool EvaluateBuiltinConstantPForLValue(const LValue &LV) {
7025 const Expr *E = LV.getLValueBase().template dyn_cast<const Expr*>();
7026 return E && isa<StringLiteral>(E) && LV.getLValueOffset().isZero();
7029 /// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
7030 /// GCC as we can manage.
7031 static bool EvaluateBuiltinConstantP(ASTContext &Ctx, const Expr *Arg) {
7032 QualType ArgType = Arg->getType();
7034 // __builtin_constant_p always has one operand. The rules which gcc follows
7035 // are not precisely documented, but are as follows:
7037 // - If the operand is of integral, floating, complex or enumeration type,
7038 // and can be folded to a known value of that type, it returns 1.
7039 // - If the operand and can be folded to a pointer to the first character
7040 // of a string literal (or such a pointer cast to an integral type), it
7043 // Otherwise, it returns 0.
7045 // FIXME: GCC also intends to return 1 for literals of aggregate types, but
7046 // its support for this does not currently work.
7047 if (ArgType->isIntegralOrEnumerationType()) {
7048 Expr::EvalResult Result;
7049 if (!Arg->EvaluateAsRValue(Result, Ctx) || Result.HasSideEffects)
7052 APValue &V = Result.Val;
7053 if (V.getKind() == APValue::Int)
7055 if (V.getKind() == APValue::LValue)
7056 return EvaluateBuiltinConstantPForLValue(V);
7057 } else if (ArgType->isFloatingType() || ArgType->isAnyComplexType()) {
7058 return Arg->isEvaluatable(Ctx);
7059 } else if (ArgType->isPointerType() || Arg->isGLValue()) {
7061 Expr::EvalStatus Status;
7062 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
7063 if ((Arg->isGLValue() ? EvaluateLValue(Arg, LV, Info)
7064 : EvaluatePointer(Arg, LV, Info)) &&
7065 !Status.HasSideEffects)
7066 return EvaluateBuiltinConstantPForLValue(LV);
7069 // Anything else isn't considered to be sufficiently constant.
7073 /// Retrieves the "underlying object type" of the given expression,
7074 /// as used by __builtin_object_size.
7075 static QualType getObjectType(APValue::LValueBase B) {
7076 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
7077 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
7078 return VD->getType();
7079 } else if (const Expr *E = B.get<const Expr*>()) {
7080 if (isa<CompoundLiteralExpr>(E))
7081 return E->getType();
7087 /// A more selective version of E->IgnoreParenCasts for
7088 /// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
7089 /// to change the type of E.
7090 /// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
7092 /// Always returns an RValue with a pointer representation.
7093 static const Expr *ignorePointerCastsAndParens(const Expr *E) {
7094 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
7096 auto *NoParens = E->IgnoreParens();
7097 auto *Cast = dyn_cast<CastExpr>(NoParens);
7098 if (Cast == nullptr)
7101 // We only conservatively allow a few kinds of casts, because this code is
7102 // inherently a simple solution that seeks to support the common case.
7103 auto CastKind = Cast->getCastKind();
7104 if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
7105 CastKind != CK_AddressSpaceConversion)
7108 auto *SubExpr = Cast->getSubExpr();
7109 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isRValue())
7111 return ignorePointerCastsAndParens(SubExpr);
7114 /// Checks to see if the given LValue's Designator is at the end of the LValue's
7115 /// record layout. e.g.
7116 /// struct { struct { int a, b; } fst, snd; } obj;
7122 /// obj.snd.b // yes
7124 /// Please note: this function is specialized for how __builtin_object_size
7125 /// views "objects".
7127 /// If this encounters an invalid RecordDecl, it will always return true.
7128 static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
7129 assert(!LVal.Designator.Invalid);
7131 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
7132 const RecordDecl *Parent = FD->getParent();
7133 Invalid = Parent->isInvalidDecl();
7134 if (Invalid || Parent->isUnion())
7136 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent);
7137 return FD->getFieldIndex() + 1 == Layout.getFieldCount();
7140 auto &Base = LVal.getLValueBase();
7141 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) {
7142 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
7144 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
7146 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) {
7147 for (auto *FD : IFD->chain()) {
7149 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid))
7156 QualType BaseType = getType(Base);
7157 if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
7158 assert(isBaseAnAllocSizeCall(Base) &&
7159 "Unsized array in non-alloc_size call?");
7160 // If this is an alloc_size base, we should ignore the initial array index
7162 BaseType = BaseType->castAs<PointerType>()->getPointeeType();
7165 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
7166 const auto &Entry = LVal.Designator.Entries[I];
7167 if (BaseType->isArrayType()) {
7168 // Because __builtin_object_size treats arrays as objects, we can ignore
7169 // the index iff this is the last array in the Designator.
7172 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType));
7173 uint64_t Index = Entry.ArrayIndex;
7174 if (Index + 1 != CAT->getSize())
7176 BaseType = CAT->getElementType();
7177 } else if (BaseType->isAnyComplexType()) {
7178 const auto *CT = BaseType->castAs<ComplexType>();
7179 uint64_t Index = Entry.ArrayIndex;
7182 BaseType = CT->getElementType();
7183 } else if (auto *FD = getAsField(Entry)) {
7185 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
7187 BaseType = FD->getType();
7189 assert(getAsBaseClass(Entry) && "Expecting cast to a base class");
7196 /// Tests to see if the LValue has a user-specified designator (that isn't
7197 /// necessarily valid). Note that this always returns 'true' if the LValue has
7198 /// an unsized array as its first designator entry, because there's currently no
7199 /// way to tell if the user typed *foo or foo[0].
7200 static bool refersToCompleteObject(const LValue &LVal) {
7201 if (LVal.Designator.Invalid)
7204 if (!LVal.Designator.Entries.empty())
7205 return LVal.Designator.isMostDerivedAnUnsizedArray();
7207 if (!LVal.InvalidBase)
7210 // If `E` is a MemberExpr, then the first part of the designator is hiding in
7212 const auto *E = LVal.Base.dyn_cast<const Expr *>();
7213 return !E || !isa<MemberExpr>(E);
7216 /// Attempts to detect a user writing into a piece of memory that's impossible
7217 /// to figure out the size of by just using types.
7218 static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
7219 const SubobjectDesignator &Designator = LVal.Designator;
7221 // - Users can only write off of the end when we have an invalid base. Invalid
7222 // bases imply we don't know where the memory came from.
7223 // - We used to be a bit more aggressive here; we'd only be conservative if
7224 // the array at the end was flexible, or if it had 0 or 1 elements. This
7225 // broke some common standard library extensions (PR30346), but was
7226 // otherwise seemingly fine. It may be useful to reintroduce this behavior
7227 // with some sort of whitelist. OTOH, it seems that GCC is always
7228 // conservative with the last element in structs (if it's an array), so our
7229 // current behavior is more compatible than a whitelisting approach would
7231 return LVal.InvalidBase &&
7232 Designator.Entries.size() == Designator.MostDerivedPathLength &&
7233 Designator.MostDerivedIsArrayElement &&
7234 isDesignatorAtObjectEnd(Ctx, LVal);
7237 /// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
7238 /// Fails if the conversion would cause loss of precision.
7239 static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
7240 CharUnits &Result) {
7241 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
7242 if (Int.ugt(CharUnitsMax))
7244 Result = CharUnits::fromQuantity(Int.getZExtValue());
7248 /// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
7249 /// determine how many bytes exist from the beginning of the object to either
7250 /// the end of the current subobject, or the end of the object itself, depending
7251 /// on what the LValue looks like + the value of Type.
7253 /// If this returns false, the value of Result is undefined.
7254 static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
7255 unsigned Type, const LValue &LVal,
7256 CharUnits &EndOffset) {
7257 bool DetermineForCompleteObject = refersToCompleteObject(LVal);
7259 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
7260 if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
7262 return HandleSizeof(Info, ExprLoc, Ty, Result);
7265 // We want to evaluate the size of the entire object. This is a valid fallback
7266 // for when Type=1 and the designator is invalid, because we're asked for an
7268 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
7269 // Type=3 wants a lower bound, so we can't fall back to this.
7270 if (Type == 3 && !DetermineForCompleteObject)
7273 llvm::APInt APEndOffset;
7274 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
7275 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
7276 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
7278 if (LVal.InvalidBase)
7281 QualType BaseTy = getObjectType(LVal.getLValueBase());
7282 return CheckedHandleSizeof(BaseTy, EndOffset);
7285 // We want to evaluate the size of a subobject.
7286 const SubobjectDesignator &Designator = LVal.Designator;
7288 // The following is a moderately common idiom in C:
7290 // struct Foo { int a; char c[1]; };
7291 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
7292 // strcpy(&F->c[0], Bar);
7294 // In order to not break too much legacy code, we need to support it.
7295 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) {
7296 // If we can resolve this to an alloc_size call, we can hand that back,
7297 // because we know for certain how many bytes there are to write to.
7298 llvm::APInt APEndOffset;
7299 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
7300 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
7301 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
7303 // If we cannot determine the size of the initial allocation, then we can't
7304 // given an accurate upper-bound. However, we are still able to give
7305 // conservative lower-bounds for Type=3.
7310 CharUnits BytesPerElem;
7311 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
7314 // According to the GCC documentation, we want the size of the subobject
7315 // denoted by the pointer. But that's not quite right -- what we actually
7316 // want is the size of the immediately-enclosing array, if there is one.
7317 int64_t ElemsRemaining;
7318 if (Designator.MostDerivedIsArrayElement &&
7319 Designator.Entries.size() == Designator.MostDerivedPathLength) {
7320 uint64_t ArraySize = Designator.getMostDerivedArraySize();
7321 uint64_t ArrayIndex = Designator.Entries.back().ArrayIndex;
7322 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
7324 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
7327 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
7331 /// \brief Tries to evaluate the __builtin_object_size for @p E. If successful,
7332 /// returns true and stores the result in @p Size.
7334 /// If @p WasError is non-null, this will report whether the failure to evaluate
7335 /// is to be treated as an Error in IntExprEvaluator.
7336 static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
7337 EvalInfo &Info, uint64_t &Size) {
7338 // Determine the denoted object.
7341 // The operand of __builtin_object_size is never evaluated for side-effects.
7342 // If there are any, but we can determine the pointed-to object anyway, then
7343 // ignore the side-effects.
7344 SpeculativeEvaluationRAII SpeculativeEval(Info);
7345 FoldOffsetRAII Fold(Info);
7347 if (E->isGLValue()) {
7348 // It's possible for us to be given GLValues if we're called via
7349 // Expr::tryEvaluateObjectSize.
7351 if (!EvaluateAsRValue(Info, E, RVal))
7353 LVal.setFrom(Info.Ctx, RVal);
7354 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info))
7358 // If we point to before the start of the object, there are no accessible
7360 if (LVal.getLValueOffset().isNegative()) {
7365 CharUnits EndOffset;
7366 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset))
7369 // If we've fallen outside of the end offset, just pretend there's nothing to
7370 // write to/read from.
7371 if (EndOffset <= LVal.getLValueOffset())
7374 Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
7378 bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
7379 if (unsigned BuiltinOp = E->getBuiltinCallee())
7380 return VisitBuiltinCallExpr(E, BuiltinOp);
7382 return ExprEvaluatorBaseTy::VisitCallExpr(E);
7385 bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
7386 unsigned BuiltinOp) {
7387 switch (unsigned BuiltinOp = E->getBuiltinCallee()) {
7389 return ExprEvaluatorBaseTy::VisitCallExpr(E);
7391 case Builtin::BI__builtin_object_size: {
7392 // The type was checked when we built the expression.
7394 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
7395 assert(Type <= 3 && "unexpected type");
7398 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size))
7399 return Success(Size, E);
7401 if (E->getArg(0)->HasSideEffects(Info.Ctx))
7402 return Success((Type & 2) ? 0 : -1, E);
7404 // Expression had no side effects, but we couldn't statically determine the
7405 // size of the referenced object.
7406 switch (Info.EvalMode) {
7407 case EvalInfo::EM_ConstantExpression:
7408 case EvalInfo::EM_PotentialConstantExpression:
7409 case EvalInfo::EM_ConstantFold:
7410 case EvalInfo::EM_EvaluateForOverflow:
7411 case EvalInfo::EM_IgnoreSideEffects:
7412 case EvalInfo::EM_OffsetFold:
7413 // Leave it to IR generation.
7415 case EvalInfo::EM_ConstantExpressionUnevaluated:
7416 case EvalInfo::EM_PotentialConstantExpressionUnevaluated:
7417 // Reduce it to a constant now.
7418 return Success((Type & 2) ? 0 : -1, E);
7421 llvm_unreachable("unexpected EvalMode");
7424 case Builtin::BI__builtin_bswap16:
7425 case Builtin::BI__builtin_bswap32:
7426 case Builtin::BI__builtin_bswap64: {
7428 if (!EvaluateInteger(E->getArg(0), Val, Info))
7431 return Success(Val.byteSwap(), E);
7434 case Builtin::BI__builtin_classify_type:
7435 return Success(EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E);
7437 // FIXME: BI__builtin_clrsb
7438 // FIXME: BI__builtin_clrsbl
7439 // FIXME: BI__builtin_clrsbll
7441 case Builtin::BI__builtin_clz:
7442 case Builtin::BI__builtin_clzl:
7443 case Builtin::BI__builtin_clzll:
7444 case Builtin::BI__builtin_clzs: {
7446 if (!EvaluateInteger(E->getArg(0), Val, Info))
7451 return Success(Val.countLeadingZeros(), E);
7454 case Builtin::BI__builtin_constant_p:
7455 return Success(EvaluateBuiltinConstantP(Info.Ctx, E->getArg(0)), E);
7457 case Builtin::BI__builtin_ctz:
7458 case Builtin::BI__builtin_ctzl:
7459 case Builtin::BI__builtin_ctzll:
7460 case Builtin::BI__builtin_ctzs: {
7462 if (!EvaluateInteger(E->getArg(0), Val, Info))
7467 return Success(Val.countTrailingZeros(), E);
7470 case Builtin::BI__builtin_eh_return_data_regno: {
7471 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
7472 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
7473 return Success(Operand, E);
7476 case Builtin::BI__builtin_expect:
7477 return Visit(E->getArg(0));
7479 case Builtin::BI__builtin_ffs:
7480 case Builtin::BI__builtin_ffsl:
7481 case Builtin::BI__builtin_ffsll: {
7483 if (!EvaluateInteger(E->getArg(0), Val, Info))
7486 unsigned N = Val.countTrailingZeros();
7487 return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
7490 case Builtin::BI__builtin_fpclassify: {
7492 if (!EvaluateFloat(E->getArg(5), Val, Info))
7495 switch (Val.getCategory()) {
7496 case APFloat::fcNaN: Arg = 0; break;
7497 case APFloat::fcInfinity: Arg = 1; break;
7498 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
7499 case APFloat::fcZero: Arg = 4; break;
7501 return Visit(E->getArg(Arg));
7504 case Builtin::BI__builtin_isinf_sign: {
7506 return EvaluateFloat(E->getArg(0), Val, Info) &&
7507 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
7510 case Builtin::BI__builtin_isinf: {
7512 return EvaluateFloat(E->getArg(0), Val, Info) &&
7513 Success(Val.isInfinity() ? 1 : 0, E);
7516 case Builtin::BI__builtin_isfinite: {
7518 return EvaluateFloat(E->getArg(0), Val, Info) &&
7519 Success(Val.isFinite() ? 1 : 0, E);
7522 case Builtin::BI__builtin_isnan: {
7524 return EvaluateFloat(E->getArg(0), Val, Info) &&
7525 Success(Val.isNaN() ? 1 : 0, E);
7528 case Builtin::BI__builtin_isnormal: {
7530 return EvaluateFloat(E->getArg(0), Val, Info) &&
7531 Success(Val.isNormal() ? 1 : 0, E);
7534 case Builtin::BI__builtin_parity:
7535 case Builtin::BI__builtin_parityl:
7536 case Builtin::BI__builtin_parityll: {
7538 if (!EvaluateInteger(E->getArg(0), Val, Info))
7541 return Success(Val.countPopulation() % 2, E);
7544 case Builtin::BI__builtin_popcount:
7545 case Builtin::BI__builtin_popcountl:
7546 case Builtin::BI__builtin_popcountll: {
7548 if (!EvaluateInteger(E->getArg(0), Val, Info))
7551 return Success(Val.countPopulation(), E);
7554 case Builtin::BIstrlen:
7555 case Builtin::BIwcslen:
7556 // A call to strlen is not a constant expression.
7557 if (Info.getLangOpts().CPlusPlus11)
7558 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
7559 << /*isConstexpr*/0 << /*isConstructor*/0
7560 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
7562 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
7564 case Builtin::BI__builtin_strlen:
7565 case Builtin::BI__builtin_wcslen: {
7566 // As an extension, we support __builtin_strlen() as a constant expression,
7567 // and support folding strlen() to a constant.
7569 if (!EvaluatePointer(E->getArg(0), String, Info))
7572 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
7574 // Fast path: if it's a string literal, search the string value.
7575 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
7576 String.getLValueBase().dyn_cast<const Expr *>())) {
7577 // The string literal may have embedded null characters. Find the first
7578 // one and truncate there.
7579 StringRef Str = S->getBytes();
7580 int64_t Off = String.Offset.getQuantity();
7581 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
7582 S->getCharByteWidth() == 1 &&
7583 // FIXME: Add fast-path for wchar_t too.
7584 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) {
7585 Str = Str.substr(Off);
7587 StringRef::size_type Pos = Str.find(0);
7588 if (Pos != StringRef::npos)
7589 Str = Str.substr(0, Pos);
7591 return Success(Str.size(), E);
7594 // Fall through to slow path to issue appropriate diagnostic.
7597 // Slow path: scan the bytes of the string looking for the terminating 0.
7598 for (uint64_t Strlen = 0; /**/; ++Strlen) {
7600 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) ||
7604 return Success(Strlen, E);
7605 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1))
7610 case Builtin::BIstrcmp:
7611 case Builtin::BIwcscmp:
7612 case Builtin::BIstrncmp:
7613 case Builtin::BIwcsncmp:
7614 case Builtin::BImemcmp:
7615 case Builtin::BIwmemcmp:
7616 // A call to strlen is not a constant expression.
7617 if (Info.getLangOpts().CPlusPlus11)
7618 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
7619 << /*isConstexpr*/0 << /*isConstructor*/0
7620 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
7622 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
7624 case Builtin::BI__builtin_strcmp:
7625 case Builtin::BI__builtin_wcscmp:
7626 case Builtin::BI__builtin_strncmp:
7627 case Builtin::BI__builtin_wcsncmp:
7628 case Builtin::BI__builtin_memcmp:
7629 case Builtin::BI__builtin_wmemcmp: {
7630 LValue String1, String2;
7631 if (!EvaluatePointer(E->getArg(0), String1, Info) ||
7632 !EvaluatePointer(E->getArg(1), String2, Info))
7635 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
7637 uint64_t MaxLength = uint64_t(-1);
7638 if (BuiltinOp != Builtin::BIstrcmp &&
7639 BuiltinOp != Builtin::BIwcscmp &&
7640 BuiltinOp != Builtin::BI__builtin_strcmp &&
7641 BuiltinOp != Builtin::BI__builtin_wcscmp) {
7643 if (!EvaluateInteger(E->getArg(2), N, Info))
7645 MaxLength = N.getExtValue();
7647 bool StopAtNull = (BuiltinOp != Builtin::BImemcmp &&
7648 BuiltinOp != Builtin::BIwmemcmp &&
7649 BuiltinOp != Builtin::BI__builtin_memcmp &&
7650 BuiltinOp != Builtin::BI__builtin_wmemcmp);
7651 for (; MaxLength; --MaxLength) {
7652 APValue Char1, Char2;
7653 if (!handleLValueToRValueConversion(Info, E, CharTy, String1, Char1) ||
7654 !handleLValueToRValueConversion(Info, E, CharTy, String2, Char2) ||
7655 !Char1.isInt() || !Char2.isInt())
7657 if (Char1.getInt() != Char2.getInt())
7658 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
7659 if (StopAtNull && !Char1.getInt())
7660 return Success(0, E);
7661 assert(!(StopAtNull && !Char2.getInt()));
7662 if (!HandleLValueArrayAdjustment(Info, E, String1, CharTy, 1) ||
7663 !HandleLValueArrayAdjustment(Info, E, String2, CharTy, 1))
7666 // We hit the strncmp / memcmp limit.
7667 return Success(0, E);
7670 case Builtin::BI__atomic_always_lock_free:
7671 case Builtin::BI__atomic_is_lock_free:
7672 case Builtin::BI__c11_atomic_is_lock_free: {
7674 if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
7677 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
7678 // of two less than the maximum inline atomic width, we know it is
7679 // lock-free. If the size isn't a power of two, or greater than the
7680 // maximum alignment where we promote atomics, we know it is not lock-free
7681 // (at least not in the sense of atomic_is_lock_free). Otherwise,
7682 // the answer can only be determined at runtime; for example, 16-byte
7683 // atomics have lock-free implementations on some, but not all,
7684 // x86-64 processors.
7686 // Check power-of-two.
7687 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
7688 if (Size.isPowerOfTwo()) {
7689 // Check against inlining width.
7690 unsigned InlineWidthBits =
7691 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
7692 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
7693 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
7694 Size == CharUnits::One() ||
7695 E->getArg(1)->isNullPointerConstant(Info.Ctx,
7696 Expr::NPC_NeverValueDependent))
7697 // OK, we will inline appropriately-aligned operations of this size,
7698 // and _Atomic(T) is appropriately-aligned.
7699 return Success(1, E);
7701 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
7702 castAs<PointerType>()->getPointeeType();
7703 if (!PointeeType->isIncompleteType() &&
7704 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
7705 // OK, we will inline operations on this object.
7706 return Success(1, E);
7711 return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
7712 Success(0, E) : Error(E);
7717 static bool HasSameBase(const LValue &A, const LValue &B) {
7718 if (!A.getLValueBase())
7719 return !B.getLValueBase();
7720 if (!B.getLValueBase())
7723 if (A.getLValueBase().getOpaqueValue() !=
7724 B.getLValueBase().getOpaqueValue()) {
7725 const Decl *ADecl = GetLValueBaseDecl(A);
7728 const Decl *BDecl = GetLValueBaseDecl(B);
7729 if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl())
7733 return IsGlobalLValue(A.getLValueBase()) ||
7734 A.getLValueCallIndex() == B.getLValueCallIndex();
7737 /// \brief Determine whether this is a pointer past the end of the complete
7738 /// object referred to by the lvalue.
7739 static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
7741 // A null pointer can be viewed as being "past the end" but we don't
7742 // choose to look at it that way here.
7743 if (!LV.getLValueBase())
7746 // If the designator is valid and refers to a subobject, we're not pointing
7748 if (!LV.getLValueDesignator().Invalid &&
7749 !LV.getLValueDesignator().isOnePastTheEnd())
7752 // A pointer to an incomplete type might be past-the-end if the type's size is
7753 // zero. We cannot tell because the type is incomplete.
7754 QualType Ty = getType(LV.getLValueBase());
7755 if (Ty->isIncompleteType())
7758 // We're a past-the-end pointer if we point to the byte after the object,
7759 // no matter what our type or path is.
7760 auto Size = Ctx.getTypeSizeInChars(Ty);
7761 return LV.getLValueOffset() == Size;
7766 /// \brief Data recursive integer evaluator of certain binary operators.
7768 /// We use a data recursive algorithm for binary operators so that we are able
7769 /// to handle extreme cases of chained binary operators without causing stack
7771 class DataRecursiveIntBinOpEvaluator {
7776 EvalResult() : Failed(false) { }
7778 void swap(EvalResult &RHS) {
7780 Failed = RHS.Failed;
7787 EvalResult LHSResult; // meaningful only for binary operator expression.
7788 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
7791 Job(Job &&) = default;
7793 void startSpeculativeEval(EvalInfo &Info) {
7794 SpecEvalRAII = SpeculativeEvaluationRAII(Info);
7798 SpeculativeEvaluationRAII SpecEvalRAII;
7801 SmallVector<Job, 16> Queue;
7803 IntExprEvaluator &IntEval;
7805 APValue &FinalResult;
7808 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
7809 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
7811 /// \brief True if \param E is a binary operator that we are going to handle
7812 /// data recursively.
7813 /// We handle binary operators that are comma, logical, or that have operands
7814 /// with integral or enumeration type.
7815 static bool shouldEnqueue(const BinaryOperator *E) {
7816 return E->getOpcode() == BO_Comma ||
7819 E->getType()->isIntegralOrEnumerationType() &&
7820 E->getLHS()->getType()->isIntegralOrEnumerationType() &&
7821 E->getRHS()->getType()->isIntegralOrEnumerationType());
7824 bool Traverse(const BinaryOperator *E) {
7826 EvalResult PrevResult;
7827 while (!Queue.empty())
7828 process(PrevResult);
7830 if (PrevResult.Failed) return false;
7832 FinalResult.swap(PrevResult.Val);
7837 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
7838 return IntEval.Success(Value, E, Result);
7840 bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
7841 return IntEval.Success(Value, E, Result);
7843 bool Error(const Expr *E) {
7844 return IntEval.Error(E);
7846 bool Error(const Expr *E, diag::kind D) {
7847 return IntEval.Error(E, D);
7850 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
7851 return Info.CCEDiag(E, D);
7854 // \brief Returns true if visiting the RHS is necessary, false otherwise.
7855 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
7856 bool &SuppressRHSDiags);
7858 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
7859 const BinaryOperator *E, APValue &Result);
7861 void EvaluateExpr(const Expr *E, EvalResult &Result) {
7862 Result.Failed = !Evaluate(Result.Val, Info, E);
7864 Result.Val = APValue();
7867 void process(EvalResult &Result);
7869 void enqueue(const Expr *E) {
7870 E = E->IgnoreParens();
7871 Queue.resize(Queue.size()+1);
7873 Queue.back().Kind = Job::AnyExprKind;
7879 bool DataRecursiveIntBinOpEvaluator::
7880 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
7881 bool &SuppressRHSDiags) {
7882 if (E->getOpcode() == BO_Comma) {
7883 // Ignore LHS but note if we could not evaluate it.
7884 if (LHSResult.Failed)
7885 return Info.noteSideEffect();
7889 if (E->isLogicalOp()) {
7891 if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) {
7892 // We were able to evaluate the LHS, see if we can get away with not
7893 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
7894 if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
7895 Success(LHSAsBool, E, LHSResult.Val);
7896 return false; // Ignore RHS
7899 LHSResult.Failed = true;
7901 // Since we weren't able to evaluate the left hand side, it
7902 // might have had side effects.
7903 if (!Info.noteSideEffect())
7906 // We can't evaluate the LHS; however, sometimes the result
7907 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
7908 // Don't ignore RHS and suppress diagnostics from this arm.
7909 SuppressRHSDiags = true;
7915 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
7916 E->getRHS()->getType()->isIntegralOrEnumerationType());
7918 if (LHSResult.Failed && !Info.noteFailure())
7919 return false; // Ignore RHS;
7924 bool DataRecursiveIntBinOpEvaluator::
7925 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
7926 const BinaryOperator *E, APValue &Result) {
7927 if (E->getOpcode() == BO_Comma) {
7928 if (RHSResult.Failed)
7930 Result = RHSResult.Val;
7934 if (E->isLogicalOp()) {
7935 bool lhsResult, rhsResult;
7936 bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
7937 bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);
7941 if (E->getOpcode() == BO_LOr)
7942 return Success(lhsResult || rhsResult, E, Result);
7944 return Success(lhsResult && rhsResult, E, Result);
7948 // We can't evaluate the LHS; however, sometimes the result
7949 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
7950 if (rhsResult == (E->getOpcode() == BO_LOr))
7951 return Success(rhsResult, E, Result);
7958 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
7959 E->getRHS()->getType()->isIntegralOrEnumerationType());
7961 if (LHSResult.Failed || RHSResult.Failed)
7964 const APValue &LHSVal = LHSResult.Val;
7965 const APValue &RHSVal = RHSResult.Val;
7967 // Handle cases like (unsigned long)&a + 4.
7968 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
7970 CharUnits AdditionalOffset =
7971 CharUnits::fromQuantity(RHSVal.getInt().getZExtValue());
7972 if (E->getOpcode() == BO_Add)
7973 Result.getLValueOffset() += AdditionalOffset;
7975 Result.getLValueOffset() -= AdditionalOffset;
7979 // Handle cases like 4 + (unsigned long)&a
7980 if (E->getOpcode() == BO_Add &&
7981 RHSVal.isLValue() && LHSVal.isInt()) {
7983 Result.getLValueOffset() +=
7984 CharUnits::fromQuantity(LHSVal.getInt().getZExtValue());
7988 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
7989 // Handle (intptr_t)&&A - (intptr_t)&&B.
7990 if (!LHSVal.getLValueOffset().isZero() ||
7991 !RHSVal.getLValueOffset().isZero())
7993 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
7994 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
7995 if (!LHSExpr || !RHSExpr)
7997 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
7998 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
7999 if (!LHSAddrExpr || !RHSAddrExpr)
8001 // Make sure both labels come from the same function.
8002 if (LHSAddrExpr->getLabel()->getDeclContext() !=
8003 RHSAddrExpr->getLabel()->getDeclContext())
8005 Result = APValue(LHSAddrExpr, RHSAddrExpr);
8009 // All the remaining cases expect both operands to be an integer
8010 if (!LHSVal.isInt() || !RHSVal.isInt())
8013 // Set up the width and signedness manually, in case it can't be deduced
8014 // from the operation we're performing.
8015 // FIXME: Don't do this in the cases where we can deduce it.
8016 APSInt Value(Info.Ctx.getIntWidth(E->getType()),
8017 E->getType()->isUnsignedIntegerOrEnumerationType());
8018 if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(),
8019 RHSVal.getInt(), Value))
8021 return Success(Value, E, Result);
8024 void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
8025 Job &job = Queue.back();
8028 case Job::AnyExprKind: {
8029 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
8030 if (shouldEnqueue(Bop)) {
8031 job.Kind = Job::BinOpKind;
8032 enqueue(Bop->getLHS());
8037 EvaluateExpr(job.E, Result);
8042 case Job::BinOpKind: {
8043 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
8044 bool SuppressRHSDiags = false;
8045 if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) {
8049 if (SuppressRHSDiags)
8050 job.startSpeculativeEval(Info);
8051 job.LHSResult.swap(Result);
8052 job.Kind = Job::BinOpVisitedLHSKind;
8053 enqueue(Bop->getRHS());
8057 case Job::BinOpVisitedLHSKind: {
8058 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
8061 Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val);
8067 llvm_unreachable("Invalid Job::Kind!");
8071 /// Used when we determine that we should fail, but can keep evaluating prior to
8072 /// noting that we had a failure.
8073 class DelayedNoteFailureRAII {
8078 DelayedNoteFailureRAII(EvalInfo &Info, bool NoteFailure = true)
8079 : Info(Info), NoteFailure(NoteFailure) {}
8080 ~DelayedNoteFailureRAII() {
8082 bool ContinueAfterFailure = Info.noteFailure();
8083 (void)ContinueAfterFailure;
8084 assert(ContinueAfterFailure &&
8085 "Shouldn't have kept evaluating on failure.");
8091 bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
8092 // We don't call noteFailure immediately because the assignment happens after
8093 // we evaluate LHS and RHS.
8094 if (!Info.keepEvaluatingAfterFailure() && E->isAssignmentOp())
8097 DelayedNoteFailureRAII MaybeNoteFailureLater(Info, E->isAssignmentOp());
8098 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
8099 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
8101 QualType LHSTy = E->getLHS()->getType();
8102 QualType RHSTy = E->getRHS()->getType();
8104 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
8105 ComplexValue LHS, RHS;
8107 if (E->isAssignmentOp()) {
8109 EvaluateLValue(E->getLHS(), LV, Info);
8111 } else if (LHSTy->isRealFloatingType()) {
8112 LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info);
8114 LHS.makeComplexFloat();
8115 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
8118 LHSOK = EvaluateComplex(E->getLHS(), LHS, Info);
8120 if (!LHSOK && !Info.noteFailure())
8123 if (E->getRHS()->getType()->isRealFloatingType()) {
8124 if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK)
8126 RHS.makeComplexFloat();
8127 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
8128 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
8131 if (LHS.isComplexFloat()) {
8132 APFloat::cmpResult CR_r =
8133 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
8134 APFloat::cmpResult CR_i =
8135 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
8137 if (E->getOpcode() == BO_EQ)
8138 return Success((CR_r == APFloat::cmpEqual &&
8139 CR_i == APFloat::cmpEqual), E);
8141 assert(E->getOpcode() == BO_NE &&
8142 "Invalid complex comparison.");
8143 return Success(((CR_r == APFloat::cmpGreaterThan ||
8144 CR_r == APFloat::cmpLessThan ||
8145 CR_r == APFloat::cmpUnordered) ||
8146 (CR_i == APFloat::cmpGreaterThan ||
8147 CR_i == APFloat::cmpLessThan ||
8148 CR_i == APFloat::cmpUnordered)), E);
8151 if (E->getOpcode() == BO_EQ)
8152 return Success((LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
8153 LHS.getComplexIntImag() == RHS.getComplexIntImag()), E);
8155 assert(E->getOpcode() == BO_NE &&
8156 "Invalid compex comparison.");
8157 return Success((LHS.getComplexIntReal() != RHS.getComplexIntReal() ||
8158 LHS.getComplexIntImag() != RHS.getComplexIntImag()), E);
8163 if (LHSTy->isRealFloatingType() &&
8164 RHSTy->isRealFloatingType()) {
8165 APFloat RHS(0.0), LHS(0.0);
8167 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info);
8168 if (!LHSOK && !Info.noteFailure())
8171 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK)
8174 APFloat::cmpResult CR = LHS.compare(RHS);
8176 switch (E->getOpcode()) {
8178 llvm_unreachable("Invalid binary operator!");
8180 return Success(CR == APFloat::cmpLessThan, E);
8182 return Success(CR == APFloat::cmpGreaterThan, E);
8184 return Success(CR == APFloat::cmpLessThan || CR == APFloat::cmpEqual, E);
8186 return Success(CR == APFloat::cmpGreaterThan || CR == APFloat::cmpEqual,
8189 return Success(CR == APFloat::cmpEqual, E);
8191 return Success(CR == APFloat::cmpGreaterThan
8192 || CR == APFloat::cmpLessThan
8193 || CR == APFloat::cmpUnordered, E);
8197 if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
8198 if (E->getOpcode() == BO_Sub || E->isComparisonOp()) {
8199 LValue LHSValue, RHSValue;
8201 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
8202 if (!LHSOK && !Info.noteFailure())
8205 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
8208 // Reject differing bases from the normal codepath; we special-case
8209 // comparisons to null.
8210 if (!HasSameBase(LHSValue, RHSValue)) {
8211 if (E->getOpcode() == BO_Sub) {
8212 // Handle &&A - &&B.
8213 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
8215 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr*>();
8216 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr*>();
8217 if (!LHSExpr || !RHSExpr)
8219 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
8220 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
8221 if (!LHSAddrExpr || !RHSAddrExpr)
8223 // Make sure both labels come from the same function.
8224 if (LHSAddrExpr->getLabel()->getDeclContext() !=
8225 RHSAddrExpr->getLabel()->getDeclContext())
8227 return Success(APValue(LHSAddrExpr, RHSAddrExpr), E);
8229 // Inequalities and subtractions between unrelated pointers have
8230 // unspecified or undefined behavior.
8231 if (!E->isEqualityOp())
8233 // A constant address may compare equal to the address of a symbol.
8234 // The one exception is that address of an object cannot compare equal
8235 // to a null pointer constant.
8236 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
8237 (!RHSValue.Base && !RHSValue.Offset.isZero()))
8239 // It's implementation-defined whether distinct literals will have
8240 // distinct addresses. In clang, the result of such a comparison is
8241 // unspecified, so it is not a constant expression. However, we do know
8242 // that the address of a literal will be non-null.
8243 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
8244 LHSValue.Base && RHSValue.Base)
8246 // We can't tell whether weak symbols will end up pointing to the same
8248 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
8250 // We can't compare the address of the start of one object with the
8251 // past-the-end address of another object, per C++ DR1652.
8252 if ((LHSValue.Base && LHSValue.Offset.isZero() &&
8253 isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) ||
8254 (RHSValue.Base && RHSValue.Offset.isZero() &&
8255 isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)))
8257 // We can't tell whether an object is at the same address as another
8258 // zero sized object.
8259 if ((RHSValue.Base && isZeroSized(LHSValue)) ||
8260 (LHSValue.Base && isZeroSized(RHSValue)))
8262 // Pointers with different bases cannot represent the same object.
8263 // (Note that clang defaults to -fmerge-all-constants, which can
8264 // lead to inconsistent results for comparisons involving the address
8265 // of a constant; this generally doesn't matter in practice.)
8266 return Success(E->getOpcode() == BO_NE, E);
8269 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
8270 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
8272 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
8273 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
8275 if (E->getOpcode() == BO_Sub) {
8276 // C++11 [expr.add]p6:
8277 // Unless both pointers point to elements of the same array object, or
8278 // one past the last element of the array object, the behavior is
8280 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
8281 !AreElementsOfSameArray(getType(LHSValue.Base),
8282 LHSDesignator, RHSDesignator))
8283 CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);
8285 QualType Type = E->getLHS()->getType();
8286 QualType ElementType = Type->getAs<PointerType>()->getPointeeType();
8288 CharUnits ElementSize;
8289 if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize))
8292 // As an extension, a type may have zero size (empty struct or union in
8293 // C, array of zero length). Pointer subtraction in such cases has
8294 // undefined behavior, so is not constant.
8295 if (ElementSize.isZero()) {
8296 Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size)
8301 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
8302 // and produce incorrect results when it overflows. Such behavior
8303 // appears to be non-conforming, but is common, so perhaps we should
8304 // assume the standard intended for such cases to be undefined behavior
8305 // and check for them.
8307 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
8308 // overflow in the final conversion to ptrdiff_t.
8310 llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
8312 llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
8314 llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true), false);
8315 APSInt TrueResult = (LHS - RHS) / ElemSize;
8316 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType()));
8318 if (Result.extend(65) != TrueResult &&
8319 !HandleOverflow(Info, E, TrueResult, E->getType()))
8321 return Success(Result, E);
8324 // C++11 [expr.rel]p3:
8325 // Pointers to void (after pointer conversions) can be compared, with a
8326 // result defined as follows: If both pointers represent the same
8327 // address or are both the null pointer value, the result is true if the
8328 // operator is <= or >= and false otherwise; otherwise the result is
8330 // We interpret this as applying to pointers to *cv* void.
8331 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset &&
8332 E->isRelationalOp())
8333 CCEDiag(E, diag::note_constexpr_void_comparison);
8335 // C++11 [expr.rel]p2:
8336 // - If two pointers point to non-static data members of the same object,
8337 // or to subobjects or array elements fo such members, recursively, the
8338 // pointer to the later declared member compares greater provided the
8339 // two members have the same access control and provided their class is
8342 // - Otherwise pointer comparisons are unspecified.
8343 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
8344 E->isRelationalOp()) {
8347 FindDesignatorMismatch(getType(LHSValue.Base), LHSDesignator,
8348 RHSDesignator, WasArrayIndex);
8349 // At the point where the designators diverge, the comparison has a
8350 // specified value if:
8351 // - we are comparing array indices
8352 // - we are comparing fields of a union, or fields with the same access
8353 // Otherwise, the result is unspecified and thus the comparison is not a
8354 // constant expression.
8355 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
8356 Mismatch < RHSDesignator.Entries.size()) {
8357 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]);
8358 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]);
8360 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
8362 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
8363 << getAsBaseClass(LHSDesignator.Entries[Mismatch])
8364 << RF->getParent() << RF;
8366 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
8367 << getAsBaseClass(RHSDesignator.Entries[Mismatch])
8368 << LF->getParent() << LF;
8369 else if (!LF->getParent()->isUnion() &&
8370 LF->getAccess() != RF->getAccess())
8371 CCEDiag(E, diag::note_constexpr_pointer_comparison_differing_access)
8372 << LF << LF->getAccess() << RF << RF->getAccess()
8377 // The comparison here must be unsigned, and performed with the same
8378 // width as the pointer.
8379 unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy);
8380 uint64_t CompareLHS = LHSOffset.getQuantity();
8381 uint64_t CompareRHS = RHSOffset.getQuantity();
8382 assert(PtrSize <= 64 && "Unexpected pointer width");
8383 uint64_t Mask = ~0ULL >> (64 - PtrSize);
8387 // If there is a base and this is a relational operator, we can only
8388 // compare pointers within the object in question; otherwise, the result
8389 // depends on where the object is located in memory.
8390 if (!LHSValue.Base.isNull() && E->isRelationalOp()) {
8391 QualType BaseTy = getType(LHSValue.Base);
8392 if (BaseTy->isIncompleteType())
8394 CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy);
8395 uint64_t OffsetLimit = Size.getQuantity();
8396 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
8400 switch (E->getOpcode()) {
8401 default: llvm_unreachable("missing comparison operator");
8402 case BO_LT: return Success(CompareLHS < CompareRHS, E);
8403 case BO_GT: return Success(CompareLHS > CompareRHS, E);
8404 case BO_LE: return Success(CompareLHS <= CompareRHS, E);
8405 case BO_GE: return Success(CompareLHS >= CompareRHS, E);
8406 case BO_EQ: return Success(CompareLHS == CompareRHS, E);
8407 case BO_NE: return Success(CompareLHS != CompareRHS, E);
8412 if (LHSTy->isMemberPointerType()) {
8413 assert(E->isEqualityOp() && "unexpected member pointer operation");
8414 assert(RHSTy->isMemberPointerType() && "invalid comparison");
8416 MemberPtr LHSValue, RHSValue;
8418 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info);
8419 if (!LHSOK && !Info.noteFailure())
8422 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK)
8425 // C++11 [expr.eq]p2:
8426 // If both operands are null, they compare equal. Otherwise if only one is
8427 // null, they compare unequal.
8428 if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
8429 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
8430 return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E);
8433 // Otherwise if either is a pointer to a virtual member function, the
8434 // result is unspecified.
8435 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
8436 if (MD->isVirtual())
8437 CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
8438 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
8439 if (MD->isVirtual())
8440 CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
8442 // Otherwise they compare equal if and only if they would refer to the
8443 // same member of the same most derived object or the same subobject if
8444 // they were dereferenced with a hypothetical object of the associated
8446 bool Equal = LHSValue == RHSValue;
8447 return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E);
8450 if (LHSTy->isNullPtrType()) {
8451 assert(E->isComparisonOp() && "unexpected nullptr operation");
8452 assert(RHSTy->isNullPtrType() && "missing pointer conversion");
8453 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
8454 // are compared, the result is true of the operator is <=, >= or ==, and
8456 BinaryOperator::Opcode Opcode = E->getOpcode();
8457 return Success(Opcode == BO_EQ || Opcode == BO_LE || Opcode == BO_GE, E);
8460 assert((!LHSTy->isIntegralOrEnumerationType() ||
8461 !RHSTy->isIntegralOrEnumerationType()) &&
8462 "DataRecursiveIntBinOpEvaluator should have handled integral types");
8463 // We can't continue from here for non-integral types.
8464 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8467 /// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
8468 /// a result as the expression's type.
8469 bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
8470 const UnaryExprOrTypeTraitExpr *E) {
8471 switch(E->getKind()) {
8472 case UETT_AlignOf: {
8473 if (E->isArgumentType())
8474 return Success(GetAlignOfType(Info, E->getArgumentType()), E);
8476 return Success(GetAlignOfExpr(Info, E->getArgumentExpr()), E);
8479 case UETT_VecStep: {
8480 QualType Ty = E->getTypeOfArgument();
8482 if (Ty->isVectorType()) {
8483 unsigned n = Ty->castAs<VectorType>()->getNumElements();
8485 // The vec_step built-in functions that take a 3-component
8486 // vector return 4. (OpenCL 1.1 spec 6.11.12)
8490 return Success(n, E);
8492 return Success(1, E);
8496 QualType SrcTy = E->getTypeOfArgument();
8497 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
8498 // the result is the size of the referenced type."
8499 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
8500 SrcTy = Ref->getPointeeType();
8503 if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof))
8505 return Success(Sizeof, E);
8507 case UETT_OpenMPRequiredSimdAlign:
8508 assert(E->isArgumentType());
8510 Info.Ctx.toCharUnitsFromBits(
8511 Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType()))
8516 llvm_unreachable("unknown expr/type trait");
8519 bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
8521 unsigned n = OOE->getNumComponents();
8524 QualType CurrentType = OOE->getTypeSourceInfo()->getType();
8525 for (unsigned i = 0; i != n; ++i) {
8526 OffsetOfNode ON = OOE->getComponent(i);
8527 switch (ON.getKind()) {
8528 case OffsetOfNode::Array: {
8529 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
8531 if (!EvaluateInteger(Idx, IdxResult, Info))
8533 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
8536 CurrentType = AT->getElementType();
8537 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
8538 Result += IdxResult.getSExtValue() * ElementSize;
8542 case OffsetOfNode::Field: {
8543 FieldDecl *MemberDecl = ON.getField();
8544 const RecordType *RT = CurrentType->getAs<RecordType>();
8547 RecordDecl *RD = RT->getDecl();
8548 if (RD->isInvalidDecl()) return false;
8549 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
8550 unsigned i = MemberDecl->getFieldIndex();
8551 assert(i < RL.getFieldCount() && "offsetof field in wrong type");
8552 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
8553 CurrentType = MemberDecl->getType().getNonReferenceType();
8557 case OffsetOfNode::Identifier:
8558 llvm_unreachable("dependent __builtin_offsetof");
8560 case OffsetOfNode::Base: {
8561 CXXBaseSpecifier *BaseSpec = ON.getBase();
8562 if (BaseSpec->isVirtual())
8565 // Find the layout of the class whose base we are looking into.
8566 const RecordType *RT = CurrentType->getAs<RecordType>();
8569 RecordDecl *RD = RT->getDecl();
8570 if (RD->isInvalidDecl()) return false;
8571 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
8573 // Find the base class itself.
8574 CurrentType = BaseSpec->getType();
8575 const RecordType *BaseRT = CurrentType->getAs<RecordType>();
8579 // Add the offset to the base.
8580 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
8585 return Success(Result, OOE);
8588 bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
8589 switch (E->getOpcode()) {
8591 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
8595 // FIXME: Should extension allow i-c-e extension expressions in its scope?
8596 // If so, we could clear the diagnostic ID.
8597 return Visit(E->getSubExpr());
8599 // The result is just the value.
8600 return Visit(E->getSubExpr());
8602 if (!Visit(E->getSubExpr()))
8604 if (!Result.isInt()) return Error(E);
8605 const APSInt &Value = Result.getInt();
8606 if (Value.isSigned() && Value.isMinSignedValue() &&
8607 !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
8610 return Success(-Value, E);
8613 if (!Visit(E->getSubExpr()))
8615 if (!Result.isInt()) return Error(E);
8616 return Success(~Result.getInt(), E);
8620 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
8622 return Success(!bres, E);
8627 /// HandleCast - This is used to evaluate implicit or explicit casts where the
8628 /// result type is integer.
8629 bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
8630 const Expr *SubExpr = E->getSubExpr();
8631 QualType DestType = E->getType();
8632 QualType SrcType = SubExpr->getType();
8634 switch (E->getCastKind()) {
8635 case CK_BaseToDerived:
8636 case CK_DerivedToBase:
8637 case CK_UncheckedDerivedToBase:
8640 case CK_ArrayToPointerDecay:
8641 case CK_FunctionToPointerDecay:
8642 case CK_NullToPointer:
8643 case CK_NullToMemberPointer:
8644 case CK_BaseToDerivedMemberPointer:
8645 case CK_DerivedToBaseMemberPointer:
8646 case CK_ReinterpretMemberPointer:
8647 case CK_ConstructorConversion:
8648 case CK_IntegralToPointer:
8650 case CK_VectorSplat:
8651 case CK_IntegralToFloating:
8652 case CK_FloatingCast:
8653 case CK_CPointerToObjCPointerCast:
8654 case CK_BlockPointerToObjCPointerCast:
8655 case CK_AnyPointerToBlockPointerCast:
8656 case CK_ObjCObjectLValueCast:
8657 case CK_FloatingRealToComplex:
8658 case CK_FloatingComplexToReal:
8659 case CK_FloatingComplexCast:
8660 case CK_FloatingComplexToIntegralComplex:
8661 case CK_IntegralRealToComplex:
8662 case CK_IntegralComplexCast:
8663 case CK_IntegralComplexToFloatingComplex:
8664 case CK_BuiltinFnToFnPtr:
8665 case CK_ZeroToOCLEvent:
8666 case CK_ZeroToOCLQueue:
8667 case CK_NonAtomicToAtomic:
8668 case CK_AddressSpaceConversion:
8669 case CK_IntToOCLSampler:
8670 llvm_unreachable("invalid cast kind for integral value");
8674 case CK_LValueBitCast:
8675 case CK_ARCProduceObject:
8676 case CK_ARCConsumeObject:
8677 case CK_ARCReclaimReturnedObject:
8678 case CK_ARCExtendBlockObject:
8679 case CK_CopyAndAutoreleaseBlockObject:
8682 case CK_UserDefinedConversion:
8683 case CK_LValueToRValue:
8684 case CK_AtomicToNonAtomic:
8686 return ExprEvaluatorBaseTy::VisitCastExpr(E);
8688 case CK_MemberPointerToBoolean:
8689 case CK_PointerToBoolean:
8690 case CK_IntegralToBoolean:
8691 case CK_FloatingToBoolean:
8692 case CK_BooleanToSignedIntegral:
8693 case CK_FloatingComplexToBoolean:
8694 case CK_IntegralComplexToBoolean: {
8696 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info))
8698 uint64_t IntResult = BoolResult;
8699 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
8700 IntResult = (uint64_t)-1;
8701 return Success(IntResult, E);
8704 case CK_IntegralCast: {
8705 if (!Visit(SubExpr))
8708 if (!Result.isInt()) {
8709 // Allow casts of address-of-label differences if they are no-ops
8710 // or narrowing. (The narrowing case isn't actually guaranteed to
8711 // be constant-evaluatable except in some narrow cases which are hard
8712 // to detect here. We let it through on the assumption the user knows
8713 // what they are doing.)
8714 if (Result.isAddrLabelDiff())
8715 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
8716 // Only allow casts of lvalues if they are lossless.
8717 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
8720 return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
8721 Result.getInt()), E);
8724 case CK_PointerToIntegral: {
8725 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8728 if (!EvaluatePointer(SubExpr, LV, Info))
8731 if (LV.getLValueBase()) {
8732 // Only allow based lvalue casts if they are lossless.
8733 // FIXME: Allow a larger integer size than the pointer size, and allow
8734 // narrowing back down to pointer width in subsequent integral casts.
8735 // FIXME: Check integer type's active bits, not its type size.
8736 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
8739 LV.Designator.setInvalid();
8740 LV.moveInto(Result);
8745 if (LV.isNullPointer())
8746 V = Info.Ctx.getTargetNullPointerValue(SrcType);
8748 V = LV.getLValueOffset().getQuantity();
8750 APSInt AsInt = Info.Ctx.MakeIntValue(V, SrcType);
8751 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
8754 case CK_IntegralComplexToReal: {
8756 if (!EvaluateComplex(SubExpr, C, Info))
8758 return Success(C.getComplexIntReal(), E);
8761 case CK_FloatingToIntegral: {
8763 if (!EvaluateFloat(SubExpr, F, Info))
8767 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
8769 return Success(Value, E);
8773 llvm_unreachable("unknown cast resulting in integral value");
8776 bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
8777 if (E->getSubExpr()->getType()->isAnyComplexType()) {
8779 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
8781 if (!LV.isComplexInt())
8783 return Success(LV.getComplexIntReal(), E);
8786 return Visit(E->getSubExpr());
8789 bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
8790 if (E->getSubExpr()->getType()->isComplexIntegerType()) {
8792 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
8794 if (!LV.isComplexInt())
8796 return Success(LV.getComplexIntImag(), E);
8799 VisitIgnoredValue(E->getSubExpr());
8800 return Success(0, E);
8803 bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
8804 return Success(E->getPackLength(), E);
8807 bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
8808 return Success(E->getValue(), E);
8811 //===----------------------------------------------------------------------===//
8813 //===----------------------------------------------------------------------===//
8816 class FloatExprEvaluator
8817 : public ExprEvaluatorBase<FloatExprEvaluator> {
8820 FloatExprEvaluator(EvalInfo &info, APFloat &result)
8821 : ExprEvaluatorBaseTy(info), Result(result) {}
8823 bool Success(const APValue &V, const Expr *e) {
8824 Result = V.getFloat();
8828 bool ZeroInitialization(const Expr *E) {
8829 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
8833 bool VisitCallExpr(const CallExpr *E);
8835 bool VisitUnaryOperator(const UnaryOperator *E);
8836 bool VisitBinaryOperator(const BinaryOperator *E);
8837 bool VisitFloatingLiteral(const FloatingLiteral *E);
8838 bool VisitCastExpr(const CastExpr *E);
8840 bool VisitUnaryReal(const UnaryOperator *E);
8841 bool VisitUnaryImag(const UnaryOperator *E);
8843 // FIXME: Missing: array subscript of vector, member of vector
8845 } // end anonymous namespace
8847 static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
8848 assert(E->isRValue() && E->getType()->isRealFloatingType());
8849 return FloatExprEvaluator(Info, Result).Visit(E);
8852 static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
8856 llvm::APFloat &Result) {
8857 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
8858 if (!S) return false;
8860 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);
8864 // Treat empty strings as if they were zero.
8865 if (S->getString().empty())
8866 fill = llvm::APInt(32, 0);
8867 else if (S->getString().getAsInteger(0, fill))
8870 if (Context.getTargetInfo().isNan2008()) {
8872 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
8874 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
8876 // Prior to IEEE 754-2008, architectures were allowed to choose whether
8877 // the first bit of their significand was set for qNaN or sNaN. MIPS chose
8878 // a different encoding to what became a standard in 2008, and for pre-
8879 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
8880 // sNaN. This is now known as "legacy NaN" encoding.
8882 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
8884 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
8890 bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
8891 switch (E->getBuiltinCallee()) {
8893 return ExprEvaluatorBaseTy::VisitCallExpr(E);
8895 case Builtin::BI__builtin_huge_val:
8896 case Builtin::BI__builtin_huge_valf:
8897 case Builtin::BI__builtin_huge_vall:
8898 case Builtin::BI__builtin_inf:
8899 case Builtin::BI__builtin_inff:
8900 case Builtin::BI__builtin_infl: {
8901 const llvm::fltSemantics &Sem =
8902 Info.Ctx.getFloatTypeSemantics(E->getType());
8903 Result = llvm::APFloat::getInf(Sem);
8907 case Builtin::BI__builtin_nans:
8908 case Builtin::BI__builtin_nansf:
8909 case Builtin::BI__builtin_nansl:
8910 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
8915 case Builtin::BI__builtin_nan:
8916 case Builtin::BI__builtin_nanf:
8917 case Builtin::BI__builtin_nanl:
8918 // If this is __builtin_nan() turn this into a nan, otherwise we
8919 // can't constant fold it.
8920 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
8925 case Builtin::BI__builtin_fabs:
8926 case Builtin::BI__builtin_fabsf:
8927 case Builtin::BI__builtin_fabsl:
8928 if (!EvaluateFloat(E->getArg(0), Result, Info))
8931 if (Result.isNegative())
8932 Result.changeSign();
8935 // FIXME: Builtin::BI__builtin_powi
8936 // FIXME: Builtin::BI__builtin_powif
8937 // FIXME: Builtin::BI__builtin_powil
8939 case Builtin::BI__builtin_copysign:
8940 case Builtin::BI__builtin_copysignf:
8941 case Builtin::BI__builtin_copysignl: {
8943 if (!EvaluateFloat(E->getArg(0), Result, Info) ||
8944 !EvaluateFloat(E->getArg(1), RHS, Info))
8946 Result.copySign(RHS);
8952 bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
8953 if (E->getSubExpr()->getType()->isAnyComplexType()) {
8955 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
8957 Result = CV.FloatReal;
8961 return Visit(E->getSubExpr());
8964 bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
8965 if (E->getSubExpr()->getType()->isAnyComplexType()) {
8967 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
8969 Result = CV.FloatImag;
8973 VisitIgnoredValue(E->getSubExpr());
8974 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
8975 Result = llvm::APFloat::getZero(Sem);
8979 bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
8980 switch (E->getOpcode()) {
8981 default: return Error(E);
8983 return EvaluateFloat(E->getSubExpr(), Result, Info);
8985 if (!EvaluateFloat(E->getSubExpr(), Result, Info))
8987 Result.changeSign();
8992 bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
8993 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
8994 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8997 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info);
8998 if (!LHSOK && !Info.noteFailure())
9000 return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK &&
9001 handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS);
9004 bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
9005 Result = E->getValue();
9009 bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
9010 const Expr* SubExpr = E->getSubExpr();
9012 switch (E->getCastKind()) {
9014 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9016 case CK_IntegralToFloating: {
9018 return EvaluateInteger(SubExpr, IntResult, Info) &&
9019 HandleIntToFloatCast(Info, E, SubExpr->getType(), IntResult,
9020 E->getType(), Result);
9023 case CK_FloatingCast: {
9024 if (!Visit(SubExpr))
9026 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
9030 case CK_FloatingComplexToReal: {
9032 if (!EvaluateComplex(SubExpr, V, Info))
9034 Result = V.getComplexFloatReal();
9040 //===----------------------------------------------------------------------===//
9041 // Complex Evaluation (for float and integer)
9042 //===----------------------------------------------------------------------===//
9045 class ComplexExprEvaluator
9046 : public ExprEvaluatorBase<ComplexExprEvaluator> {
9047 ComplexValue &Result;
9050 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
9051 : ExprEvaluatorBaseTy(info), Result(Result) {}
9053 bool Success(const APValue &V, const Expr *e) {
9058 bool ZeroInitialization(const Expr *E);
9060 //===--------------------------------------------------------------------===//
9062 //===--------------------------------------------------------------------===//
9064 bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
9065 bool VisitCastExpr(const CastExpr *E);
9066 bool VisitBinaryOperator(const BinaryOperator *E);
9067 bool VisitUnaryOperator(const UnaryOperator *E);
9068 bool VisitInitListExpr(const InitListExpr *E);
9070 } // end anonymous namespace
9072 static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
9074 assert(E->isRValue() && E->getType()->isAnyComplexType());
9075 return ComplexExprEvaluator(Info, Result).Visit(E);
9078 bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
9079 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
9080 if (ElemTy->isRealFloatingType()) {
9081 Result.makeComplexFloat();
9082 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy));
9083 Result.FloatReal = Zero;
9084 Result.FloatImag = Zero;
9086 Result.makeComplexInt();
9087 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy);
9088 Result.IntReal = Zero;
9089 Result.IntImag = Zero;
9094 bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
9095 const Expr* SubExpr = E->getSubExpr();
9097 if (SubExpr->getType()->isRealFloatingType()) {
9098 Result.makeComplexFloat();
9099 APFloat &Imag = Result.FloatImag;
9100 if (!EvaluateFloat(SubExpr, Imag, Info))
9103 Result.FloatReal = APFloat(Imag.getSemantics());
9106 assert(SubExpr->getType()->isIntegerType() &&
9107 "Unexpected imaginary literal.");
9109 Result.makeComplexInt();
9110 APSInt &Imag = Result.IntImag;
9111 if (!EvaluateInteger(SubExpr, Imag, Info))
9114 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
9119 bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
9121 switch (E->getCastKind()) {
9123 case CK_BaseToDerived:
9124 case CK_DerivedToBase:
9125 case CK_UncheckedDerivedToBase:
9128 case CK_ArrayToPointerDecay:
9129 case CK_FunctionToPointerDecay:
9130 case CK_NullToPointer:
9131 case CK_NullToMemberPointer:
9132 case CK_BaseToDerivedMemberPointer:
9133 case CK_DerivedToBaseMemberPointer:
9134 case CK_MemberPointerToBoolean:
9135 case CK_ReinterpretMemberPointer:
9136 case CK_ConstructorConversion:
9137 case CK_IntegralToPointer:
9138 case CK_PointerToIntegral:
9139 case CK_PointerToBoolean:
9141 case CK_VectorSplat:
9142 case CK_IntegralCast:
9143 case CK_BooleanToSignedIntegral:
9144 case CK_IntegralToBoolean:
9145 case CK_IntegralToFloating:
9146 case CK_FloatingToIntegral:
9147 case CK_FloatingToBoolean:
9148 case CK_FloatingCast:
9149 case CK_CPointerToObjCPointerCast:
9150 case CK_BlockPointerToObjCPointerCast:
9151 case CK_AnyPointerToBlockPointerCast:
9152 case CK_ObjCObjectLValueCast:
9153 case CK_FloatingComplexToReal:
9154 case CK_FloatingComplexToBoolean:
9155 case CK_IntegralComplexToReal:
9156 case CK_IntegralComplexToBoolean:
9157 case CK_ARCProduceObject:
9158 case CK_ARCConsumeObject:
9159 case CK_ARCReclaimReturnedObject:
9160 case CK_ARCExtendBlockObject:
9161 case CK_CopyAndAutoreleaseBlockObject:
9162 case CK_BuiltinFnToFnPtr:
9163 case CK_ZeroToOCLEvent:
9164 case CK_ZeroToOCLQueue:
9165 case CK_NonAtomicToAtomic:
9166 case CK_AddressSpaceConversion:
9167 case CK_IntToOCLSampler:
9168 llvm_unreachable("invalid cast kind for complex value");
9170 case CK_LValueToRValue:
9171 case CK_AtomicToNonAtomic:
9173 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9176 case CK_LValueBitCast:
9177 case CK_UserDefinedConversion:
9180 case CK_FloatingRealToComplex: {
9181 APFloat &Real = Result.FloatReal;
9182 if (!EvaluateFloat(E->getSubExpr(), Real, Info))
9185 Result.makeComplexFloat();
9186 Result.FloatImag = APFloat(Real.getSemantics());
9190 case CK_FloatingComplexCast: {
9191 if (!Visit(E->getSubExpr()))
9194 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9196 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9198 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
9199 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
9202 case CK_FloatingComplexToIntegralComplex: {
9203 if (!Visit(E->getSubExpr()))
9206 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9208 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9209 Result.makeComplexInt();
9210 return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
9211 To, Result.IntReal) &&
9212 HandleFloatToIntCast(Info, E, From, Result.FloatImag,
9213 To, Result.IntImag);
9216 case CK_IntegralRealToComplex: {
9217 APSInt &Real = Result.IntReal;
9218 if (!EvaluateInteger(E->getSubExpr(), Real, Info))
9221 Result.makeComplexInt();
9222 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
9226 case CK_IntegralComplexCast: {
9227 if (!Visit(E->getSubExpr()))
9230 QualType To = E->getType()->getAs<ComplexType>()->getElementType();
9232 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType();
9234 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
9235 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
9239 case CK_IntegralComplexToFloatingComplex: {
9240 if (!Visit(E->getSubExpr()))
9243 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
9245 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
9246 Result.makeComplexFloat();
9247 return HandleIntToFloatCast(Info, E, From, Result.IntReal,
9248 To, Result.FloatReal) &&
9249 HandleIntToFloatCast(Info, E, From, Result.IntImag,
9250 To, Result.FloatImag);
9254 llvm_unreachable("unknown cast resulting in complex value");
9257 bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
9258 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
9259 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
9261 // Track whether the LHS or RHS is real at the type system level. When this is
9262 // the case we can simplify our evaluation strategy.
9263 bool LHSReal = false, RHSReal = false;
9266 if (E->getLHS()->getType()->isRealFloatingType()) {
9268 APFloat &Real = Result.FloatReal;
9269 LHSOK = EvaluateFloat(E->getLHS(), Real, Info);
9271 Result.makeComplexFloat();
9272 Result.FloatImag = APFloat(Real.getSemantics());
9275 LHSOK = Visit(E->getLHS());
9277 if (!LHSOK && !Info.noteFailure())
9281 if (E->getRHS()->getType()->isRealFloatingType()) {
9283 APFloat &Real = RHS.FloatReal;
9284 if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK)
9286 RHS.makeComplexFloat();
9287 RHS.FloatImag = APFloat(Real.getSemantics());
9288 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
9291 assert(!(LHSReal && RHSReal) &&
9292 "Cannot have both operands of a complex operation be real.");
9293 switch (E->getOpcode()) {
9294 default: return Error(E);
9296 if (Result.isComplexFloat()) {
9297 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
9298 APFloat::rmNearestTiesToEven);
9300 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
9302 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
9303 APFloat::rmNearestTiesToEven);
9305 Result.getComplexIntReal() += RHS.getComplexIntReal();
9306 Result.getComplexIntImag() += RHS.getComplexIntImag();
9310 if (Result.isComplexFloat()) {
9311 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
9312 APFloat::rmNearestTiesToEven);
9314 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
9315 Result.getComplexFloatImag().changeSign();
9316 } else if (!RHSReal) {
9317 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
9318 APFloat::rmNearestTiesToEven);
9321 Result.getComplexIntReal() -= RHS.getComplexIntReal();
9322 Result.getComplexIntImag() -= RHS.getComplexIntImag();
9326 if (Result.isComplexFloat()) {
9327 // This is an implementation of complex multiplication according to the
9328 // constraints laid out in C11 Annex G. The implemantion uses the
9329 // following naming scheme:
9330 // (a + ib) * (c + id)
9331 ComplexValue LHS = Result;
9332 APFloat &A = LHS.getComplexFloatReal();
9333 APFloat &B = LHS.getComplexFloatImag();
9334 APFloat &C = RHS.getComplexFloatReal();
9335 APFloat &D = RHS.getComplexFloatImag();
9336 APFloat &ResR = Result.getComplexFloatReal();
9337 APFloat &ResI = Result.getComplexFloatImag();
9339 assert(!RHSReal && "Cannot have two real operands for a complex op!");
9342 } else if (RHSReal) {
9346 // In the fully general case, we need to handle NaNs and infinities
9354 if (ResR.isNaN() && ResI.isNaN()) {
9355 bool Recalc = false;
9356 if (A.isInfinity() || B.isInfinity()) {
9357 A = APFloat::copySign(
9358 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
9359 B = APFloat::copySign(
9360 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
9362 C = APFloat::copySign(APFloat(C.getSemantics()), C);
9364 D = APFloat::copySign(APFloat(D.getSemantics()), D);
9367 if (C.isInfinity() || D.isInfinity()) {
9368 C = APFloat::copySign(
9369 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
9370 D = APFloat::copySign(
9371 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
9373 A = APFloat::copySign(APFloat(A.getSemantics()), A);
9375 B = APFloat::copySign(APFloat(B.getSemantics()), B);
9378 if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
9379 AD.isInfinity() || BC.isInfinity())) {
9381 A = APFloat::copySign(APFloat(A.getSemantics()), A);
9383 B = APFloat::copySign(APFloat(B.getSemantics()), B);
9385 C = APFloat::copySign(APFloat(C.getSemantics()), C);
9387 D = APFloat::copySign(APFloat(D.getSemantics()), D);
9391 ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
9392 ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
9397 ComplexValue LHS = Result;
9398 Result.getComplexIntReal() =
9399 (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
9400 LHS.getComplexIntImag() * RHS.getComplexIntImag());
9401 Result.getComplexIntImag() =
9402 (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
9403 LHS.getComplexIntImag() * RHS.getComplexIntReal());
9407 if (Result.isComplexFloat()) {
9408 // This is an implementation of complex division according to the
9409 // constraints laid out in C11 Annex G. The implemantion uses the
9410 // following naming scheme:
9411 // (a + ib) / (c + id)
9412 ComplexValue LHS = Result;
9413 APFloat &A = LHS.getComplexFloatReal();
9414 APFloat &B = LHS.getComplexFloatImag();
9415 APFloat &C = RHS.getComplexFloatReal();
9416 APFloat &D = RHS.getComplexFloatImag();
9417 APFloat &ResR = Result.getComplexFloatReal();
9418 APFloat &ResI = Result.getComplexFloatImag();
9424 // No real optimizations we can do here, stub out with zero.
9425 B = APFloat::getZero(A.getSemantics());
9428 APFloat MaxCD = maxnum(abs(C), abs(D));
9429 if (MaxCD.isFinite()) {
9430 DenomLogB = ilogb(MaxCD);
9431 C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven);
9432 D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven);
9434 APFloat Denom = C * C + D * D;
9435 ResR = scalbn((A * C + B * D) / Denom, -DenomLogB,
9436 APFloat::rmNearestTiesToEven);
9437 ResI = scalbn((B * C - A * D) / Denom, -DenomLogB,
9438 APFloat::rmNearestTiesToEven);
9439 if (ResR.isNaN() && ResI.isNaN()) {
9440 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
9441 ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A;
9442 ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B;
9443 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
9445 A = APFloat::copySign(
9446 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
9447 B = APFloat::copySign(
9448 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
9449 ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D);
9450 ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D);
9451 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
9452 C = APFloat::copySign(
9453 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
9454 D = APFloat::copySign(
9455 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
9456 ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D);
9457 ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D);
9462 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
9463 return Error(E, diag::note_expr_divide_by_zero);
9465 ComplexValue LHS = Result;
9466 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
9467 RHS.getComplexIntImag() * RHS.getComplexIntImag();
9468 Result.getComplexIntReal() =
9469 (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
9470 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
9471 Result.getComplexIntImag() =
9472 (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
9473 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
9481 bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
9482 // Get the operand value into 'Result'.
9483 if (!Visit(E->getSubExpr()))
9486 switch (E->getOpcode()) {
9492 // The result is always just the subexpr.
9495 if (Result.isComplexFloat()) {
9496 Result.getComplexFloatReal().changeSign();
9497 Result.getComplexFloatImag().changeSign();
9500 Result.getComplexIntReal() = -Result.getComplexIntReal();
9501 Result.getComplexIntImag() = -Result.getComplexIntImag();
9505 if (Result.isComplexFloat())
9506 Result.getComplexFloatImag().changeSign();
9508 Result.getComplexIntImag() = -Result.getComplexIntImag();
9513 bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
9514 if (E->getNumInits() == 2) {
9515 if (E->getType()->isComplexType()) {
9516 Result.makeComplexFloat();
9517 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info))
9519 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info))
9522 Result.makeComplexInt();
9523 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info))
9525 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info))
9530 return ExprEvaluatorBaseTy::VisitInitListExpr(E);
9533 //===----------------------------------------------------------------------===//
9534 // Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
9535 // implicit conversion.
9536 //===----------------------------------------------------------------------===//
9539 class AtomicExprEvaluator :
9540 public ExprEvaluatorBase<AtomicExprEvaluator> {
9543 AtomicExprEvaluator(EvalInfo &Info, APValue &Result)
9544 : ExprEvaluatorBaseTy(Info), Result(Result) {}
9546 bool Success(const APValue &V, const Expr *E) {
9551 bool ZeroInitialization(const Expr *E) {
9552 ImplicitValueInitExpr VIE(
9553 E->getType()->castAs<AtomicType>()->getValueType());
9554 return Evaluate(Result, Info, &VIE);
9557 bool VisitCastExpr(const CastExpr *E) {
9558 switch (E->getCastKind()) {
9560 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9561 case CK_NonAtomicToAtomic:
9562 return Evaluate(Result, Info, E->getSubExpr());
9566 } // end anonymous namespace
9568 static bool EvaluateAtomic(const Expr *E, APValue &Result, EvalInfo &Info) {
9569 assert(E->isRValue() && E->getType()->isAtomicType());
9570 return AtomicExprEvaluator(Info, Result).Visit(E);
9573 //===----------------------------------------------------------------------===//
9574 // Void expression evaluation, primarily for a cast to void on the LHS of a
9576 //===----------------------------------------------------------------------===//
9579 class VoidExprEvaluator
9580 : public ExprEvaluatorBase<VoidExprEvaluator> {
9582 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
9584 bool Success(const APValue &V, const Expr *e) { return true; }
9586 bool VisitCastExpr(const CastExpr *E) {
9587 switch (E->getCastKind()) {
9589 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9591 VisitIgnoredValue(E->getSubExpr());
9596 bool VisitCallExpr(const CallExpr *E) {
9597 switch (E->getBuiltinCallee()) {
9599 return ExprEvaluatorBaseTy::VisitCallExpr(E);
9600 case Builtin::BI__assume:
9601 case Builtin::BI__builtin_assume:
9602 // The argument is not evaluated!
9607 } // end anonymous namespace
9609 static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
9610 assert(E->isRValue() && E->getType()->isVoidType());
9611 return VoidExprEvaluator(Info).Visit(E);
9614 //===----------------------------------------------------------------------===//
9615 // Top level Expr::EvaluateAsRValue method.
9616 //===----------------------------------------------------------------------===//
9618 static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
9619 // In C, function designators are not lvalues, but we evaluate them as if they
9621 QualType T = E->getType();
9622 if (E->isGLValue() || T->isFunctionType()) {
9624 if (!EvaluateLValue(E, LV, Info))
9626 LV.moveInto(Result);
9627 } else if (T->isVectorType()) {
9628 if (!EvaluateVector(E, Result, Info))
9630 } else if (T->isIntegralOrEnumerationType()) {
9631 if (!IntExprEvaluator(Info, Result).Visit(E))
9633 } else if (T->hasPointerRepresentation()) {
9635 if (!EvaluatePointer(E, LV, Info))
9637 LV.moveInto(Result);
9638 } else if (T->isRealFloatingType()) {
9639 llvm::APFloat F(0.0);
9640 if (!EvaluateFloat(E, F, Info))
9642 Result = APValue(F);
9643 } else if (T->isAnyComplexType()) {
9645 if (!EvaluateComplex(E, C, Info))
9648 } else if (T->isMemberPointerType()) {
9650 if (!EvaluateMemberPointer(E, P, Info))
9654 } else if (T->isArrayType()) {
9656 LV.set(E, Info.CurrentCall->Index);
9657 APValue &Value = Info.CurrentCall->createTemporary(E, false);
9658 if (!EvaluateArray(E, LV, Value, Info))
9661 } else if (T->isRecordType()) {
9663 LV.set(E, Info.CurrentCall->Index);
9664 APValue &Value = Info.CurrentCall->createTemporary(E, false);
9665 if (!EvaluateRecord(E, LV, Value, Info))
9668 } else if (T->isVoidType()) {
9669 if (!Info.getLangOpts().CPlusPlus11)
9670 Info.CCEDiag(E, diag::note_constexpr_nonliteral)
9672 if (!EvaluateVoid(E, Info))
9674 } else if (T->isAtomicType()) {
9675 if (!EvaluateAtomic(E, Result, Info))
9677 } else if (Info.getLangOpts().CPlusPlus11) {
9678 Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
9681 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
9688 /// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
9689 /// cases, the in-place evaluation is essential, since later initializers for
9690 /// an object can indirectly refer to subobjects which were initialized earlier.
9691 static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
9692 const Expr *E, bool AllowNonLiteralTypes) {
9693 assert(!E->isValueDependent());
9695 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
9698 if (E->isRValue()) {
9699 // Evaluate arrays and record types in-place, so that later initializers can
9700 // refer to earlier-initialized members of the object.
9701 if (E->getType()->isArrayType())
9702 return EvaluateArray(E, This, Result, Info);
9703 else if (E->getType()->isRecordType())
9704 return EvaluateRecord(E, This, Result, Info);
9707 // For any other type, in-place evaluation is unimportant.
9708 return Evaluate(Result, Info, E);
9711 /// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
9712 /// lvalue-to-rvalue cast if it is an lvalue.
9713 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
9714 if (E->getType().isNull())
9717 if (!CheckLiteralType(Info, E))
9720 if (!::Evaluate(Result, Info, E))
9723 if (E->isGLValue()) {
9725 LV.setFrom(Info.Ctx, Result);
9726 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
9730 // Check this core constant expression is a constant expression.
9731 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result);
9734 static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
9735 const ASTContext &Ctx, bool &IsConst) {
9736 // Fast-path evaluations of integer literals, since we sometimes see files
9737 // containing vast quantities of these.
9738 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) {
9739 Result.Val = APValue(APSInt(L->getValue(),
9740 L->getType()->isUnsignedIntegerType()));
9745 // This case should be rare, but we need to check it before we check on
9747 if (Exp->getType().isNull()) {
9752 // FIXME: Evaluating values of large array and record types can cause
9753 // performance problems. Only do so in C++11 for now.
9754 if (Exp->isRValue() && (Exp->getType()->isArrayType() ||
9755 Exp->getType()->isRecordType()) &&
9756 !Ctx.getLangOpts().CPlusPlus11) {
9764 /// EvaluateAsRValue - Return true if this is a constant which we can fold using
9765 /// any crazy technique (that has nothing to do with language standards) that
9766 /// we want to. If this function returns true, it returns the folded constant
9767 /// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
9768 /// will be applied to the result.
9769 bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const {
9771 if (FastEvaluateAsRValue(this, Result, Ctx, IsConst))
9774 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
9775 return ::EvaluateAsRValue(Info, this, Result.Val);
9778 bool Expr::EvaluateAsBooleanCondition(bool &Result,
9779 const ASTContext &Ctx) const {
9781 return EvaluateAsRValue(Scratch, Ctx) &&
9782 HandleConversionToBool(Scratch.Val, Result);
9785 static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
9786 Expr::SideEffectsKind SEK) {
9787 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
9788 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
9791 bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx,
9792 SideEffectsKind AllowSideEffects) const {
9793 if (!getType()->isIntegralOrEnumerationType())
9796 EvalResult ExprResult;
9797 if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isInt() ||
9798 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
9801 Result = ExprResult.Val.getInt();
9805 bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
9806 SideEffectsKind AllowSideEffects) const {
9807 if (!getType()->isRealFloatingType())
9810 EvalResult ExprResult;
9811 if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isFloat() ||
9812 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
9815 Result = ExprResult.Val.getFloat();
9819 bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const {
9820 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
9823 if (!EvaluateLValue(this, LV, Info) || Result.HasSideEffects ||
9824 !CheckLValueConstantExpression(Info, getExprLoc(),
9825 Ctx.getLValueReferenceType(getType()), LV))
9828 LV.moveInto(Result.Val);
9832 bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
9834 SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
9835 // FIXME: Evaluating initializers for large array and record types can cause
9836 // performance problems. Only do so in C++11 for now.
9837 if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
9838 !Ctx.getLangOpts().CPlusPlus11)
9841 Expr::EvalStatus EStatus;
9842 EStatus.Diag = &Notes;
9844 EvalInfo InitInfo(Ctx, EStatus, VD->isConstexpr()
9845 ? EvalInfo::EM_ConstantExpression
9846 : EvalInfo::EM_ConstantFold);
9847 InitInfo.setEvaluatingDecl(VD, Value);
9852 // C++11 [basic.start.init]p2:
9853 // Variables with static storage duration or thread storage duration shall be
9854 // zero-initialized before any other initialization takes place.
9855 // This behavior is not present in C.
9856 if (Ctx.getLangOpts().CPlusPlus && !VD->hasLocalStorage() &&
9857 !VD->getType()->isReferenceType()) {
9858 ImplicitValueInitExpr VIE(VD->getType());
9859 if (!EvaluateInPlace(Value, InitInfo, LVal, &VIE,
9860 /*AllowNonLiteralTypes=*/true))
9864 if (!EvaluateInPlace(Value, InitInfo, LVal, this,
9865 /*AllowNonLiteralTypes=*/true) ||
9866 EStatus.HasSideEffects)
9869 return CheckConstantExpression(InitInfo, VD->getLocation(), VD->getType(),
9873 /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
9874 /// constant folded, but discard the result.
9875 bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
9877 return EvaluateAsRValue(Result, Ctx) &&
9878 !hasUnacceptableSideEffect(Result, SEK);
9881 APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
9882 SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
9883 EvalResult EvalResult;
9884 EvalResult.Diag = Diag;
9885 bool Result = EvaluateAsRValue(EvalResult, Ctx);
9887 assert(Result && "Could not evaluate expression");
9888 assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer");
9890 return EvalResult.Val.getInt();
9893 void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
9895 EvalResult EvalResult;
9896 if (!FastEvaluateAsRValue(this, EvalResult, Ctx, IsConst)) {
9897 EvalInfo Info(Ctx, EvalResult, EvalInfo::EM_EvaluateForOverflow);
9898 (void)::EvaluateAsRValue(Info, this, EvalResult.Val);
9902 bool Expr::EvalResult::isGlobalLValue() const {
9903 assert(Val.isLValue());
9904 return IsGlobalLValue(Val.getLValueBase());
9908 /// isIntegerConstantExpr - this recursive routine will test if an expression is
9909 /// an integer constant expression.
9911 /// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
9914 // CheckICE - This function does the fundamental ICE checking: the returned
9915 // ICEDiag contains an ICEKind indicating whether the expression is an ICE,
9916 // and a (possibly null) SourceLocation indicating the location of the problem.
9918 // Note that to reduce code duplication, this helper does no evaluation
9919 // itself; the caller checks whether the expression is evaluatable, and
9920 // in the rare cases where CheckICE actually cares about the evaluated
9921 // value, it calls into Evalute.
9926 /// This expression is an ICE.
9928 /// This expression is not an ICE, but if it isn't evaluated, it's
9929 /// a legal subexpression for an ICE. This return value is used to handle
9930 /// the comma operator in C99 mode, and non-constant subexpressions.
9931 IK_ICEIfUnevaluated,
9932 /// This expression is not an ICE, and is not a legal subexpression for one.
9940 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
9945 static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }
9947 static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }
9949 static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
9950 Expr::EvalResult EVResult;
9951 if (!E->EvaluateAsRValue(EVResult, Ctx) || EVResult.HasSideEffects ||
9952 !EVResult.Val.isInt())
9953 return ICEDiag(IK_NotICE, E->getLocStart());
9958 static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
9959 assert(!E->isValueDependent() && "Should not see value dependent exprs!");
9960 if (!E->getType()->isIntegralOrEnumerationType())
9961 return ICEDiag(IK_NotICE, E->getLocStart());
9963 switch (E->getStmtClass()) {
9964 #define ABSTRACT_STMT(Node)
9965 #define STMT(Node, Base) case Expr::Node##Class:
9966 #define EXPR(Node, Base)
9967 #include "clang/AST/StmtNodes.inc"
9968 case Expr::PredefinedExprClass:
9969 case Expr::FloatingLiteralClass:
9970 case Expr::ImaginaryLiteralClass:
9971 case Expr::StringLiteralClass:
9972 case Expr::ArraySubscriptExprClass:
9973 case Expr::OMPArraySectionExprClass:
9974 case Expr::MemberExprClass:
9975 case Expr::CompoundAssignOperatorClass:
9976 case Expr::CompoundLiteralExprClass:
9977 case Expr::ExtVectorElementExprClass:
9978 case Expr::DesignatedInitExprClass:
9979 case Expr::ArrayInitLoopExprClass:
9980 case Expr::ArrayInitIndexExprClass:
9981 case Expr::NoInitExprClass:
9982 case Expr::DesignatedInitUpdateExprClass:
9983 case Expr::ImplicitValueInitExprClass:
9984 case Expr::ParenListExprClass:
9985 case Expr::VAArgExprClass:
9986 case Expr::AddrLabelExprClass:
9987 case Expr::StmtExprClass:
9988 case Expr::CXXMemberCallExprClass:
9989 case Expr::CUDAKernelCallExprClass:
9990 case Expr::CXXDynamicCastExprClass:
9991 case Expr::CXXTypeidExprClass:
9992 case Expr::CXXUuidofExprClass:
9993 case Expr::MSPropertyRefExprClass:
9994 case Expr::MSPropertySubscriptExprClass:
9995 case Expr::CXXNullPtrLiteralExprClass:
9996 case Expr::UserDefinedLiteralClass:
9997 case Expr::CXXThisExprClass:
9998 case Expr::CXXThrowExprClass:
9999 case Expr::CXXNewExprClass:
10000 case Expr::CXXDeleteExprClass:
10001 case Expr::CXXPseudoDestructorExprClass:
10002 case Expr::UnresolvedLookupExprClass:
10003 case Expr::TypoExprClass:
10004 case Expr::DependentScopeDeclRefExprClass:
10005 case Expr::CXXConstructExprClass:
10006 case Expr::CXXInheritedCtorInitExprClass:
10007 case Expr::CXXStdInitializerListExprClass:
10008 case Expr::CXXBindTemporaryExprClass:
10009 case Expr::ExprWithCleanupsClass:
10010 case Expr::CXXTemporaryObjectExprClass:
10011 case Expr::CXXUnresolvedConstructExprClass:
10012 case Expr::CXXDependentScopeMemberExprClass:
10013 case Expr::UnresolvedMemberExprClass:
10014 case Expr::ObjCStringLiteralClass:
10015 case Expr::ObjCBoxedExprClass:
10016 case Expr::ObjCArrayLiteralClass:
10017 case Expr::ObjCDictionaryLiteralClass:
10018 case Expr::ObjCEncodeExprClass:
10019 case Expr::ObjCMessageExprClass:
10020 case Expr::ObjCSelectorExprClass:
10021 case Expr::ObjCProtocolExprClass:
10022 case Expr::ObjCIvarRefExprClass:
10023 case Expr::ObjCPropertyRefExprClass:
10024 case Expr::ObjCSubscriptRefExprClass:
10025 case Expr::ObjCIsaExprClass:
10026 case Expr::ObjCAvailabilityCheckExprClass:
10027 case Expr::ShuffleVectorExprClass:
10028 case Expr::ConvertVectorExprClass:
10029 case Expr::BlockExprClass:
10030 case Expr::NoStmtClass:
10031 case Expr::OpaqueValueExprClass:
10032 case Expr::PackExpansionExprClass:
10033 case Expr::SubstNonTypeTemplateParmPackExprClass:
10034 case Expr::FunctionParmPackExprClass:
10035 case Expr::AsTypeExprClass:
10036 case Expr::ObjCIndirectCopyRestoreExprClass:
10037 case Expr::MaterializeTemporaryExprClass:
10038 case Expr::PseudoObjectExprClass:
10039 case Expr::AtomicExprClass:
10040 case Expr::LambdaExprClass:
10041 case Expr::CXXFoldExprClass:
10042 case Expr::CoawaitExprClass:
10043 case Expr::CoyieldExprClass:
10044 return ICEDiag(IK_NotICE, E->getLocStart());
10046 case Expr::InitListExprClass: {
10047 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
10048 // form "T x = { a };" is equivalent to "T x = a;".
10049 // Unless we're initializing a reference, T is a scalar as it is known to be
10050 // of integral or enumeration type.
10052 if (cast<InitListExpr>(E)->getNumInits() == 1)
10053 return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx);
10054 return ICEDiag(IK_NotICE, E->getLocStart());
10057 case Expr::SizeOfPackExprClass:
10058 case Expr::GNUNullExprClass:
10059 // GCC considers the GNU __null value to be an integral constant expression.
10062 case Expr::SubstNonTypeTemplateParmExprClass:
10064 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
10066 case Expr::ParenExprClass:
10067 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
10068 case Expr::GenericSelectionExprClass:
10069 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
10070 case Expr::IntegerLiteralClass:
10071 case Expr::CharacterLiteralClass:
10072 case Expr::ObjCBoolLiteralExprClass:
10073 case Expr::CXXBoolLiteralExprClass:
10074 case Expr::CXXScalarValueInitExprClass:
10075 case Expr::TypeTraitExprClass:
10076 case Expr::ArrayTypeTraitExprClass:
10077 case Expr::ExpressionTraitExprClass:
10078 case Expr::CXXNoexceptExprClass:
10080 case Expr::CallExprClass:
10081 case Expr::CXXOperatorCallExprClass: {
10082 // C99 6.6/3 allows function calls within unevaluated subexpressions of
10083 // constant expressions, but they can never be ICEs because an ICE cannot
10084 // contain an operand of (pointer to) function type.
10085 const CallExpr *CE = cast<CallExpr>(E);
10086 if (CE->getBuiltinCallee())
10087 return CheckEvalInICE(E, Ctx);
10088 return ICEDiag(IK_NotICE, E->getLocStart());
10090 case Expr::DeclRefExprClass: {
10091 if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl()))
10093 const ValueDecl *D = dyn_cast<ValueDecl>(cast<DeclRefExpr>(E)->getDecl());
10094 if (Ctx.getLangOpts().CPlusPlus &&
10095 D && IsConstNonVolatile(D->getType())) {
10096 // Parameter variables are never constants. Without this check,
10097 // getAnyInitializer() can find a default argument, which leads
10099 if (isa<ParmVarDecl>(D))
10100 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10103 // A variable of non-volatile const-qualified integral or enumeration
10104 // type initialized by an ICE can be used in ICEs.
10105 if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) {
10106 if (!Dcl->getType()->isIntegralOrEnumerationType())
10107 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10110 // Look for a declaration of this variable that has an initializer, and
10111 // check whether it is an ICE.
10112 if (Dcl->getAnyInitializer(VD) && VD->checkInitIsICE())
10115 return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation());
10118 return ICEDiag(IK_NotICE, E->getLocStart());
10120 case Expr::UnaryOperatorClass: {
10121 const UnaryOperator *Exp = cast<UnaryOperator>(E);
10122 switch (Exp->getOpcode()) {
10130 // C99 6.6/3 allows increment and decrement within unevaluated
10131 // subexpressions of constant expressions, but they can never be ICEs
10132 // because an ICE cannot contain an lvalue operand.
10133 return ICEDiag(IK_NotICE, E->getLocStart());
10141 return CheckICE(Exp->getSubExpr(), Ctx);
10144 // OffsetOf falls through here.
10146 case Expr::OffsetOfExprClass: {
10147 // Note that per C99, offsetof must be an ICE. And AFAIK, using
10148 // EvaluateAsRValue matches the proposed gcc behavior for cases like
10149 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect
10150 // compliance: we should warn earlier for offsetof expressions with
10151 // array subscripts that aren't ICEs, and if the array subscripts
10152 // are ICEs, the value of the offsetof must be an integer constant.
10153 return CheckEvalInICE(E, Ctx);
10155 case Expr::UnaryExprOrTypeTraitExprClass: {
10156 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
10157 if ((Exp->getKind() == UETT_SizeOf) &&
10158 Exp->getTypeOfArgument()->isVariableArrayType())
10159 return ICEDiag(IK_NotICE, E->getLocStart());
10162 case Expr::BinaryOperatorClass: {
10163 const BinaryOperator *Exp = cast<BinaryOperator>(E);
10164 switch (Exp->getOpcode()) {
10178 // C99 6.6/3 allows assignments within unevaluated subexpressions of
10179 // constant expressions, but they can never be ICEs because an ICE cannot
10180 // contain an lvalue operand.
10181 return ICEDiag(IK_NotICE, E->getLocStart());
10200 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
10201 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
10202 if (Exp->getOpcode() == BO_Div ||
10203 Exp->getOpcode() == BO_Rem) {
10204 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
10205 // we don't evaluate one.
10206 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
10207 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
10209 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10210 if (REval.isSigned() && REval.isAllOnesValue()) {
10211 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
10212 if (LEval.isMinSignedValue())
10213 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10217 if (Exp->getOpcode() == BO_Comma) {
10218 if (Ctx.getLangOpts().C99) {
10219 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
10220 // if it isn't evaluated.
10221 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
10222 return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart());
10224 // In both C89 and C++, commas in ICEs are illegal.
10225 return ICEDiag(IK_NotICE, E->getLocStart());
10228 return Worst(LHSResult, RHSResult);
10232 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
10233 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
10234 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
10235 // Rare case where the RHS has a comma "side-effect"; we need
10236 // to actually check the condition to see whether the side
10237 // with the comma is evaluated.
10238 if ((Exp->getOpcode() == BO_LAnd) !=
10239 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
10244 return Worst(LHSResult, RHSResult);
10248 case Expr::ImplicitCastExprClass:
10249 case Expr::CStyleCastExprClass:
10250 case Expr::CXXFunctionalCastExprClass:
10251 case Expr::CXXStaticCastExprClass:
10252 case Expr::CXXReinterpretCastExprClass:
10253 case Expr::CXXConstCastExprClass:
10254 case Expr::ObjCBridgedCastExprClass: {
10255 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
10256 if (isa<ExplicitCastExpr>(E)) {
10257 if (const FloatingLiteral *FL
10258 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
10259 unsigned DestWidth = Ctx.getIntWidth(E->getType());
10260 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
10261 APSInt IgnoredVal(DestWidth, !DestSigned);
10263 // If the value does not fit in the destination type, the behavior is
10264 // undefined, so we are not required to treat it as a constant
10266 if (FL->getValue().convertToInteger(IgnoredVal,
10267 llvm::APFloat::rmTowardZero,
10268 &Ignored) & APFloat::opInvalidOp)
10269 return ICEDiag(IK_NotICE, E->getLocStart());
10273 switch (cast<CastExpr>(E)->getCastKind()) {
10274 case CK_LValueToRValue:
10275 case CK_AtomicToNonAtomic:
10276 case CK_NonAtomicToAtomic:
10278 case CK_IntegralToBoolean:
10279 case CK_IntegralCast:
10280 return CheckICE(SubExpr, Ctx);
10282 return ICEDiag(IK_NotICE, E->getLocStart());
10285 case Expr::BinaryConditionalOperatorClass: {
10286 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
10287 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
10288 if (CommonResult.Kind == IK_NotICE) return CommonResult;
10289 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
10290 if (FalseResult.Kind == IK_NotICE) return FalseResult;
10291 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
10292 if (FalseResult.Kind == IK_ICEIfUnevaluated &&
10293 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
10294 return FalseResult;
10296 case Expr::ConditionalOperatorClass: {
10297 const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
10298 // If the condition (ignoring parens) is a __builtin_constant_p call,
10299 // then only the true side is actually considered in an integer constant
10300 // expression, and it is fully evaluated. This is an important GNU
10301 // extension. See GCC PR38377 for discussion.
10302 if (const CallExpr *CallCE
10303 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
10304 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
10305 return CheckEvalInICE(E, Ctx);
10306 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
10307 if (CondResult.Kind == IK_NotICE)
10310 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
10311 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
10313 if (TrueResult.Kind == IK_NotICE)
10315 if (FalseResult.Kind == IK_NotICE)
10316 return FalseResult;
10317 if (CondResult.Kind == IK_ICEIfUnevaluated)
10319 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
10321 // Rare case where the diagnostics depend on which side is evaluated
10322 // Note that if we get here, CondResult is 0, and at least one of
10323 // TrueResult and FalseResult is non-zero.
10324 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
10325 return FalseResult;
10328 case Expr::CXXDefaultArgExprClass:
10329 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
10330 case Expr::CXXDefaultInitExprClass:
10331 return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx);
10332 case Expr::ChooseExprClass: {
10333 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
10337 llvm_unreachable("Invalid StmtClass!");
10340 /// Evaluate an expression as a C++11 integral constant expression.
10341 static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
10343 llvm::APSInt *Value,
10344 SourceLocation *Loc) {
10345 if (!E->getType()->isIntegralOrEnumerationType()) {
10346 if (Loc) *Loc = E->getExprLoc();
10351 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc))
10354 if (!Result.isInt()) {
10355 if (Loc) *Loc = E->getExprLoc();
10359 if (Value) *Value = Result.getInt();
10363 bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
10364 SourceLocation *Loc) const {
10365 if (Ctx.getLangOpts().CPlusPlus11)
10366 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc);
10368 ICEDiag D = CheckICE(this, Ctx);
10369 if (D.Kind != IK_ICE) {
10370 if (Loc) *Loc = D.Loc;
10376 bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, const ASTContext &Ctx,
10377 SourceLocation *Loc, bool isEvaluated) const {
10378 if (Ctx.getLangOpts().CPlusPlus11)
10379 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc);
10381 if (!isIntegerConstantExpr(Ctx, Loc))
10383 // The only possible side-effects here are due to UB discovered in the
10384 // evaluation (for instance, INT_MAX + 1). In such a case, we are still
10385 // required to treat the expression as an ICE, so we produce the folded
10387 if (!EvaluateAsInt(Value, Ctx, SE_AllowSideEffects))
10388 llvm_unreachable("ICE cannot be evaluated!");
10392 bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
10393 return CheckICE(this, Ctx).Kind == IK_ICE;
10396 bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
10397 SourceLocation *Loc) const {
10398 // We support this checking in C++98 mode in order to diagnose compatibility
10400 assert(Ctx.getLangOpts().CPlusPlus);
10402 // Build evaluation settings.
10403 Expr::EvalStatus Status;
10404 SmallVector<PartialDiagnosticAt, 8> Diags;
10405 Status.Diag = &Diags;
10406 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
10409 bool IsConstExpr = ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch);
10411 if (!Diags.empty()) {
10412 IsConstExpr = false;
10413 if (Loc) *Loc = Diags[0].first;
10414 } else if (!IsConstExpr) {
10415 // FIXME: This shouldn't happen.
10416 if (Loc) *Loc = getExprLoc();
10419 return IsConstExpr;
10422 bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
10423 const FunctionDecl *Callee,
10424 ArrayRef<const Expr*> Args,
10425 const Expr *This) const {
10426 Expr::EvalStatus Status;
10427 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
10430 const LValue *ThisPtr = nullptr;
10433 auto *MD = dyn_cast<CXXMethodDecl>(Callee);
10434 assert(MD && "Don't provide `this` for non-methods.");
10435 assert(!MD->isStatic() && "Don't provide `this` for static methods.");
10437 if (EvaluateObjectArgument(Info, This, ThisVal))
10438 ThisPtr = &ThisVal;
10439 if (Info.EvalStatus.HasSideEffects)
10443 ArgVector ArgValues(Args.size());
10444 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
10446 if ((*I)->isValueDependent() ||
10447 !Evaluate(ArgValues[I - Args.begin()], Info, *I))
10448 // If evaluation fails, throw away the argument entirely.
10449 ArgValues[I - Args.begin()] = APValue();
10450 if (Info.EvalStatus.HasSideEffects)
10454 // Build fake call to Callee.
10455 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr,
10457 return Evaluate(Value, Info, this) && !Info.EvalStatus.HasSideEffects;
10460 bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
10462 PartialDiagnosticAt> &Diags) {
10463 // FIXME: It would be useful to check constexpr function templates, but at the
10464 // moment the constant expression evaluator cannot cope with the non-rigorous
10465 // ASTs which we build for dependent expressions.
10466 if (FD->isDependentContext())
10469 Expr::EvalStatus Status;
10470 Status.Diag = &Diags;
10472 EvalInfo Info(FD->getASTContext(), Status,
10473 EvalInfo::EM_PotentialConstantExpression);
10475 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
10476 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;
10478 // Fabricate an arbitrary expression on the stack and pretend that it
10479 // is a temporary being used as the 'this' pointer.
10481 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
10482 This.set(&VIE, Info.CurrentCall->Index);
10484 ArrayRef<const Expr*> Args;
10487 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
10488 // Evaluate the call as a constant initializer, to allow the construction
10489 // of objects of non-literal types.
10490 Info.setEvaluatingDecl(This.getLValueBase(), Scratch);
10491 HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch);
10493 SourceLocation Loc = FD->getLocation();
10494 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : nullptr,
10495 Args, FD->getBody(), Info, Scratch, nullptr);
10498 return Diags.empty();
10501 bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
10502 const FunctionDecl *FD,
10504 PartialDiagnosticAt> &Diags) {
10505 Expr::EvalStatus Status;
10506 Status.Diag = &Diags;
10508 EvalInfo Info(FD->getASTContext(), Status,
10509 EvalInfo::EM_PotentialConstantExpressionUnevaluated);
10511 // Fabricate a call stack frame to give the arguments a plausible cover story.
10512 ArrayRef<const Expr*> Args;
10513 ArgVector ArgValues(0);
10514 bool Success = EvaluateArgs(Args, ArgValues, Info);
10517 "Failed to set up arguments for potential constant evaluation");
10518 CallStackFrame Frame(Info, SourceLocation(), FD, nullptr, ArgValues.data());
10520 APValue ResultScratch;
10521 Evaluate(ResultScratch, Info, E);
10522 return Diags.empty();
10525 bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
10526 unsigned Type) const {
10527 if (!getType()->isPointerType())
10530 Expr::EvalStatus Status;
10531 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
10532 return tryEvaluateBuiltinObjectSize(this, Type, Info, Result);