| //===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the Expr constant evaluator. |
| // |
| // Constant expression evaluation produces four main results: |
| // |
| // * A success/failure flag indicating whether constant folding was successful. |
| // This is the 'bool' return value used by most of the code in this file. A |
| // 'false' return value indicates that constant folding has failed, and any |
| // appropriate diagnostic has already been produced. |
| // |
| // * An evaluated result, valid only if constant folding has not failed. |
| // |
| // * A flag indicating if evaluation encountered (unevaluated) side-effects. |
| // These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1), |
| // where it is possible to determine the evaluated result regardless. |
| // |
| // * A set of notes indicating why the evaluation was not a constant expression |
| // (under the C++11 / C++1y rules only, at the moment), or, if folding failed |
| // too, why the expression could not be folded. |
| // |
| // If we are checking for a potential constant expression, failure to constant |
| // fold a potential constant sub-expression will be indicated by a 'false' |
| // return value (the expression could not be folded) and no diagnostic (the |
| // expression is not necessarily non-constant). |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/AST/APValue.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/ASTDiagnostic.h" |
| #include "clang/AST/CharUnits.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/RecordLayout.h" |
| #include "clang/AST/StmtVisitor.h" |
| #include "clang/AST/TypeLoc.h" |
| #include "clang/Basic/Builtins.h" |
| #include "clang/Basic/TargetInfo.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <cstring> |
| #include <functional> |
| |
| using namespace clang; |
| using llvm::APSInt; |
| using llvm::APFloat; |
| |
| static bool IsGlobalLValue(APValue::LValueBase B); |
| |
| namespace { |
| struct LValue; |
| struct CallStackFrame; |
| struct EvalInfo; |
| |
| static QualType getType(APValue::LValueBase B) { |
| if (!B) return QualType(); |
| if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) |
| return D->getType(); |
| |
| const Expr *Base = B.get<const Expr*>(); |
| |
| // For a materialized temporary, the type of the temporary we materialized |
| // may not be the type of the expression. |
| if (const MaterializeTemporaryExpr *MTE = |
| dyn_cast<MaterializeTemporaryExpr>(Base)) { |
| SmallVector<const Expr *, 2> CommaLHSs; |
| SmallVector<SubobjectAdjustment, 2> Adjustments; |
| const Expr *Temp = MTE->GetTemporaryExpr(); |
| const Expr *Inner = Temp->skipRValueSubobjectAdjustments(CommaLHSs, |
| Adjustments); |
| // Keep any cv-qualifiers from the reference if we generated a temporary |
| // for it. |
| if (Inner != Temp) |
| return Inner->getType(); |
| } |
| |
| return Base->getType(); |
| } |
| |
| /// Get an LValue path entry, which is known to not be an array index, as a |
| /// field or base class. |
| static |
| APValue::BaseOrMemberType getAsBaseOrMember(APValue::LValuePathEntry E) { |
| APValue::BaseOrMemberType Value; |
| Value.setFromOpaqueValue(E.BaseOrMember); |
| return Value; |
| } |
| |
| /// Get an LValue path entry, which is known to not be an array index, as a |
| /// field declaration. |
| static const FieldDecl *getAsField(APValue::LValuePathEntry E) { |
| return dyn_cast<FieldDecl>(getAsBaseOrMember(E).getPointer()); |
| } |
| /// Get an LValue path entry, which is known to not be an array index, as a |
| /// base class declaration. |
| static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) { |
| return dyn_cast<CXXRecordDecl>(getAsBaseOrMember(E).getPointer()); |
| } |
| /// Determine whether this LValue path entry for a base class names a virtual |
| /// base class. |
| static bool isVirtualBaseClass(APValue::LValuePathEntry E) { |
| return getAsBaseOrMember(E).getInt(); |
| } |
| |
| /// Find the path length and type of the most-derived subobject in the given |
| /// path, and find the size of the containing array, if any. |
| static |
| unsigned findMostDerivedSubobject(ASTContext &Ctx, QualType Base, |
| ArrayRef<APValue::LValuePathEntry> Path, |
| uint64_t &ArraySize, QualType &Type) { |
| unsigned MostDerivedLength = 0; |
| Type = Base; |
| for (unsigned I = 0, N = Path.size(); I != N; ++I) { |
| if (Type->isArrayType()) { |
| const ConstantArrayType *CAT = |
| cast<ConstantArrayType>(Ctx.getAsArrayType(Type)); |
| Type = CAT->getElementType(); |
| ArraySize = CAT->getSize().getZExtValue(); |
| MostDerivedLength = I + 1; |
| } else if (Type->isAnyComplexType()) { |
| const ComplexType *CT = Type->castAs<ComplexType>(); |
| Type = CT->getElementType(); |
| ArraySize = 2; |
| MostDerivedLength = I + 1; |
| } else if (const FieldDecl *FD = getAsField(Path[I])) { |
| Type = FD->getType(); |
| ArraySize = 0; |
| MostDerivedLength = I + 1; |
| } else { |
| // Path[I] describes a base class. |
| ArraySize = 0; |
| } |
| } |
| return MostDerivedLength; |
| } |
| |
| // The order of this enum is important for diagnostics. |
| enum CheckSubobjectKind { |
| CSK_Base, CSK_Derived, CSK_Field, CSK_ArrayToPointer, CSK_ArrayIndex, |
| CSK_This, CSK_Real, CSK_Imag |
| }; |
| |
| /// A path from a glvalue to a subobject of that glvalue. |
| struct SubobjectDesignator { |
| /// True if the subobject was named in a manner not supported by C++11. Such |
| /// lvalues can still be folded, but they are not core constant expressions |
| /// and we cannot perform lvalue-to-rvalue conversions on them. |
| bool Invalid : 1; |
| |
| /// Is this a pointer one past the end of an object? |
| bool IsOnePastTheEnd : 1; |
| |
| /// The length of the path to the most-derived object of which this is a |
| /// subobject. |
| unsigned MostDerivedPathLength : 30; |
| |
| /// The size of the array of which the most-derived object is an element, or |
| /// 0 if the most-derived object is not an array element. |
| uint64_t MostDerivedArraySize; |
| |
| /// The type of the most derived object referred to by this address. |
| QualType MostDerivedType; |
| |
| typedef APValue::LValuePathEntry PathEntry; |
| |
| /// The entries on the path from the glvalue to the designated subobject. |
| SmallVector<PathEntry, 8> Entries; |
| |
| SubobjectDesignator() : Invalid(true) {} |
| |
| explicit SubobjectDesignator(QualType T) |
| : Invalid(false), IsOnePastTheEnd(false), MostDerivedPathLength(0), |
| MostDerivedArraySize(0), MostDerivedType(T) {} |
| |
| SubobjectDesignator(ASTContext &Ctx, const APValue &V) |
| : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false), |
| MostDerivedPathLength(0), MostDerivedArraySize(0) { |
| if (!Invalid) { |
| IsOnePastTheEnd = V.isLValueOnePastTheEnd(); |
| ArrayRef<PathEntry> VEntries = V.getLValuePath(); |
| Entries.insert(Entries.end(), VEntries.begin(), VEntries.end()); |
| if (V.getLValueBase()) |
| MostDerivedPathLength = |
| findMostDerivedSubobject(Ctx, getType(V.getLValueBase()), |
| V.getLValuePath(), MostDerivedArraySize, |
| MostDerivedType); |
| } |
| } |
| |
| void setInvalid() { |
| Invalid = true; |
| Entries.clear(); |
| } |
| |
| /// Determine whether this is a one-past-the-end pointer. |
| bool isOnePastTheEnd() const { |
| if (IsOnePastTheEnd) |
| return true; |
| if (MostDerivedArraySize && |
| Entries[MostDerivedPathLength - 1].ArrayIndex == MostDerivedArraySize) |
| return true; |
| return false; |
| } |
| |
| /// Check that this refers to a valid subobject. |
| bool isValidSubobject() const { |
| if (Invalid) |
| return false; |
| return !isOnePastTheEnd(); |
| } |
| /// Check that this refers to a valid subobject, and if not, produce a |
| /// relevant diagnostic and set the designator as invalid. |
| bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK); |
| |
| /// Update this designator to refer to the first element within this array. |
| void addArrayUnchecked(const ConstantArrayType *CAT) { |
| PathEntry Entry; |
| Entry.ArrayIndex = 0; |
| Entries.push_back(Entry); |
| |
| // This is a most-derived object. |
| MostDerivedType = CAT->getElementType(); |
| MostDerivedArraySize = CAT->getSize().getZExtValue(); |
| MostDerivedPathLength = Entries.size(); |
| } |
| /// Update this designator to refer to the given base or member of this |
| /// object. |
| void addDeclUnchecked(const Decl *D, bool Virtual = false) { |
| PathEntry Entry; |
| APValue::BaseOrMemberType Value(D, Virtual); |
| Entry.BaseOrMember = Value.getOpaqueValue(); |
| Entries.push_back(Entry); |
| |
| // If this isn't a base class, it's a new most-derived object. |
| if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) { |
| MostDerivedType = FD->getType(); |
| MostDerivedArraySize = 0; |
| MostDerivedPathLength = Entries.size(); |
| } |
| } |
| /// Update this designator to refer to the given complex component. |
| void addComplexUnchecked(QualType EltTy, bool Imag) { |
| PathEntry Entry; |
| Entry.ArrayIndex = Imag; |
| Entries.push_back(Entry); |
| |
| // This is technically a most-derived object, though in practice this |
| // is unlikely to matter. |
| MostDerivedType = EltTy; |
| MostDerivedArraySize = 2; |
| MostDerivedPathLength = Entries.size(); |
| } |
| void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E, uint64_t N); |
| /// Add N to the address of this subobject. |
| void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) { |
| if (Invalid) return; |
| if (MostDerivedPathLength == Entries.size() && MostDerivedArraySize) { |
| Entries.back().ArrayIndex += N; |
| if (Entries.back().ArrayIndex > MostDerivedArraySize) { |
| diagnosePointerArithmetic(Info, E, Entries.back().ArrayIndex); |
| setInvalid(); |
| } |
| return; |
| } |
| // [expr.add]p4: For the purposes of these operators, a pointer to a |
| // nonarray object behaves the same as a pointer to the first element of |
| // an array of length one with the type of the object as its element type. |
| if (IsOnePastTheEnd && N == (uint64_t)-1) |
| IsOnePastTheEnd = false; |
| else if (!IsOnePastTheEnd && N == 1) |
| IsOnePastTheEnd = true; |
| else if (N != 0) { |
| diagnosePointerArithmetic(Info, E, uint64_t(IsOnePastTheEnd) + N); |
| setInvalid(); |
| } |
| } |
| }; |
| |
| /// A stack frame in the constexpr call stack. |
| struct CallStackFrame { |
| EvalInfo &Info; |
| |
| /// Parent - The caller of this stack frame. |
| CallStackFrame *Caller; |
| |
| /// CallLoc - The location of the call expression for this call. |
| SourceLocation CallLoc; |
| |
| /// Callee - The function which was called. |
| const FunctionDecl *Callee; |
| |
| /// Index - The call index of this call. |
| unsigned Index; |
| |
| /// This - The binding for the this pointer in this call, if any. |
| const LValue *This; |
| |
| /// Arguments - Parameter bindings for this function call, indexed by |
| /// parameters' function scope indices. |
| APValue *Arguments; |
| |
| // Note that we intentionally use std::map here so that references to |
| // values are stable. |
| typedef std::map<const void*, APValue> MapTy; |
| typedef MapTy::const_iterator temp_iterator; |
| /// Temporaries - Temporary lvalues materialized within this stack frame. |
| MapTy Temporaries; |
| |
| CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, |
| const FunctionDecl *Callee, const LValue *This, |
| APValue *Arguments); |
| ~CallStackFrame(); |
| |
| APValue *getTemporary(const void *Key) { |
| MapTy::iterator I = Temporaries.find(Key); |
| return I == Temporaries.end() ? 0 : &I->second; |
| } |
| APValue &createTemporary(const void *Key, bool IsLifetimeExtended); |
| }; |
| |
| /// Temporarily override 'this'. |
| class ThisOverrideRAII { |
| public: |
| ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable) |
| : Frame(Frame), OldThis(Frame.This) { |
| if (Enable) |
| Frame.This = NewThis; |
| } |
| ~ThisOverrideRAII() { |
| Frame.This = OldThis; |
| } |
| private: |
| CallStackFrame &Frame; |
| const LValue *OldThis; |
| }; |
| |
| /// A partial diagnostic which we might know in advance that we are not going |
| /// to emit. |
| class OptionalDiagnostic { |
| PartialDiagnostic *Diag; |
| |
| public: |
| explicit OptionalDiagnostic(PartialDiagnostic *Diag = 0) : Diag(Diag) {} |
| |
| template<typename T> |
| OptionalDiagnostic &operator<<(const T &v) { |
| if (Diag) |
| *Diag << v; |
| return *this; |
| } |
| |
| OptionalDiagnostic &operator<<(const APSInt &I) { |
| if (Diag) { |
| SmallVector<char, 32> Buffer; |
| I.toString(Buffer); |
| *Diag << StringRef(Buffer.data(), Buffer.size()); |
| } |
| return *this; |
| } |
| |
| OptionalDiagnostic &operator<<(const APFloat &F) { |
| if (Diag) { |
| // FIXME: Force the precision of the source value down so we don't |
| // print digits which are usually useless (we don't really care here if |
| // we truncate a digit by accident in edge cases). Ideally, |
| // APFloat::toString would automatically print the shortest |
| // representation which rounds to the correct value, but it's a bit |
| // tricky to implement. |
| unsigned precision = |
| llvm::APFloat::semanticsPrecision(F.getSemantics()); |
| precision = (precision * 59 + 195) / 196; |
| SmallVector<char, 32> Buffer; |
| F.toString(Buffer, precision); |
| *Diag << StringRef(Buffer.data(), Buffer.size()); |
| } |
| return *this; |
| } |
| }; |
| |
| /// A cleanup, and a flag indicating whether it is lifetime-extended. |
| class Cleanup { |
| llvm::PointerIntPair<APValue*, 1, bool> Value; |
| |
| public: |
| Cleanup(APValue *Val, bool IsLifetimeExtended) |
| : Value(Val, IsLifetimeExtended) {} |
| |
| bool isLifetimeExtended() const { return Value.getInt(); } |
| void endLifetime() { |
| *Value.getPointer() = APValue(); |
| } |
| }; |
| |
| /// EvalInfo - This is a private struct used by the evaluator to capture |
| /// information about a subexpression as it is folded. It retains information |
| /// about the AST context, but also maintains information about the folded |
| /// expression. |
| /// |
| /// If an expression could be evaluated, it is still possible it is not a C |
| /// "integer constant expression" or constant expression. If not, this struct |
| /// captures information about how and why not. |
| /// |
| /// One bit of information passed *into* the request for constant folding |
| /// indicates whether the subexpression is "evaluated" or not according to C |
| /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can |
| /// evaluate the expression regardless of what the RHS is, but C only allows |
| /// certain things in certain situations. |
| struct EvalInfo { |
| ASTContext &Ctx; |
| |
| /// EvalStatus - Contains information about the evaluation. |
| Expr::EvalStatus &EvalStatus; |
| |
| /// CurrentCall - The top of the constexpr call stack. |
| CallStackFrame *CurrentCall; |
| |
| /// CallStackDepth - The number of calls in the call stack right now. |
| unsigned CallStackDepth; |
| |
| /// NextCallIndex - The next call index to assign. |
| unsigned NextCallIndex; |
| |
| /// StepsLeft - The remaining number of evaluation steps we're permitted |
| /// to perform. This is essentially a limit for the number of statements |
| /// we will evaluate. |
| unsigned StepsLeft; |
| |
| /// BottomFrame - The frame in which evaluation started. This must be |
| /// initialized after CurrentCall and CallStackDepth. |
| CallStackFrame BottomFrame; |
| |
| /// A stack of values whose lifetimes end at the end of some surrounding |
| /// evaluation frame. |
| llvm::SmallVector<Cleanup, 16> CleanupStack; |
| |
| /// EvaluatingDecl - This is the declaration whose initializer is being |
| /// evaluated, if any. |
| APValue::LValueBase EvaluatingDecl; |
| |
| /// EvaluatingDeclValue - This is the value being constructed for the |
| /// declaration whose initializer is being evaluated, if any. |
| APValue *EvaluatingDeclValue; |
| |
| /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further |
| /// notes attached to it will also be stored, otherwise they will not be. |
| bool HasActiveDiagnostic; |
| |
| enum EvaluationMode { |
| /// Evaluate as a constant expression. Stop if we find that the expression |
| /// is not a constant expression. |
| EM_ConstantExpression, |
| |
| /// Evaluate as a potential constant expression. Keep going if we hit a |
| /// construct that we can't evaluate yet (because we don't yet know the |
| /// value of something) but stop if we hit something that could never be |
| /// a constant expression. |
| EM_PotentialConstantExpression, |
| |
| /// Fold the expression to a constant. Stop if we hit a side-effect that |
| /// we can't model. |
| EM_ConstantFold, |
| |
| /// Evaluate the expression looking for integer overflow and similar |
| /// issues. Don't worry about side-effects, and try to visit all |
| /// subexpressions. |
| EM_EvaluateForOverflow, |
| |
| /// Evaluate in any way we know how. Don't worry about side-effects that |
| /// can't be modeled. |
| EM_IgnoreSideEffects |
| } EvalMode; |
| |
| /// Are we checking whether the expression is a potential constant |
| /// expression? |
| bool checkingPotentialConstantExpression() const { |
| return EvalMode == EM_PotentialConstantExpression; |
| } |
| |
| /// Are we checking an expression for overflow? |
| // FIXME: We should check for any kind of undefined or suspicious behavior |
| // in such constructs, not just overflow. |
| bool checkingForOverflow() { return EvalMode == EM_EvaluateForOverflow; } |
| |
| EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode) |
| : Ctx(const_cast<ASTContext&>(C)), EvalStatus(S), CurrentCall(0), |
| CallStackDepth(0), NextCallIndex(1), |
| StepsLeft(getLangOpts().ConstexprStepLimit), |
| BottomFrame(*this, SourceLocation(), 0, 0, 0), |
| EvaluatingDecl((const ValueDecl*)0), EvaluatingDeclValue(0), |
| HasActiveDiagnostic(false), EvalMode(Mode) {} |
| |
| void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value) { |
| EvaluatingDecl = Base; |
| EvaluatingDeclValue = &Value; |
| } |
| |
| const LangOptions &getLangOpts() const { return Ctx.getLangOpts(); } |
| |
| bool CheckCallLimit(SourceLocation Loc) { |
| // Don't perform any constexpr calls (other than the call we're checking) |
| // when checking a potential constant expression. |
| if (checkingPotentialConstantExpression() && CallStackDepth > 1) |
| return false; |
| if (NextCallIndex == 0) { |
| // NextCallIndex has wrapped around. |
| Diag(Loc, diag::note_constexpr_call_limit_exceeded); |
| return false; |
| } |
| if (CallStackDepth <= getLangOpts().ConstexprCallDepth) |
| return true; |
| Diag(Loc, diag::note_constexpr_depth_limit_exceeded) |
| << getLangOpts().ConstexprCallDepth; |
| return false; |
| } |
| |
| CallStackFrame *getCallFrame(unsigned CallIndex) { |
| assert(CallIndex && "no call index in getCallFrame"); |
| // We will eventually hit BottomFrame, which has Index 1, so Frame can't |
| // be null in this loop. |
| CallStackFrame *Frame = CurrentCall; |
| while (Frame->Index > CallIndex) |
| Frame = Frame->Caller; |
| return (Frame->Index == CallIndex) ? Frame : 0; |
| } |
| |
| bool nextStep(const Stmt *S) { |
| if (!StepsLeft) { |
| Diag(S->getLocStart(), diag::note_constexpr_step_limit_exceeded); |
| return false; |
| } |
| --StepsLeft; |
| return true; |
| } |
| |
| private: |
| /// Add a diagnostic to the diagnostics list. |
| PartialDiagnostic &addDiag(SourceLocation Loc, diag::kind DiagId) { |
| PartialDiagnostic PD(DiagId, Ctx.getDiagAllocator()); |
| EvalStatus.Diag->push_back(std::make_pair(Loc, PD)); |
| return EvalStatus.Diag->back().second; |
| } |
| |
| /// Add notes containing a call stack to the current point of evaluation. |
| void addCallStack(unsigned Limit); |
| |
| public: |
| /// Diagnose that the evaluation cannot be folded. |
| OptionalDiagnostic Diag(SourceLocation Loc, diag::kind DiagId |
| = diag::note_invalid_subexpr_in_const_expr, |
| unsigned ExtraNotes = 0) { |
| if (EvalStatus.Diag) { |
| // If we have a prior diagnostic, it will be noting that the expression |
| // isn't a constant expression. This diagnostic is more important, |
| // unless we require this evaluation to produce a constant expression. |
| // |
| // FIXME: We might want to show both diagnostics to the user in |
| // EM_ConstantFold mode. |
| if (!EvalStatus.Diag->empty()) { |
| switch (EvalMode) { |
| case EM_ConstantFold: |
| case EM_IgnoreSideEffects: |
| case EM_EvaluateForOverflow: |
| if (!EvalStatus.HasSideEffects) |
| break; |
| // We've had side-effects; we want the diagnostic from them, not |
| // some later problem. |
| case EM_ConstantExpression: |
| case EM_PotentialConstantExpression: |
| HasActiveDiagnostic = false; |
| return OptionalDiagnostic(); |
| } |
| } |
| |
| unsigned CallStackNotes = CallStackDepth - 1; |
| unsigned Limit = Ctx.getDiagnostics().getConstexprBacktraceLimit(); |
| if (Limit) |
| CallStackNotes = std::min(CallStackNotes, Limit + 1); |
| if (checkingPotentialConstantExpression()) |
| CallStackNotes = 0; |
| |
| HasActiveDiagnostic = true; |
| EvalStatus.Diag->clear(); |
| EvalStatus.Diag->reserve(1 + ExtraNotes + CallStackNotes); |
| addDiag(Loc, DiagId); |
| if (!checkingPotentialConstantExpression()) |
| addCallStack(Limit); |
| return OptionalDiagnostic(&(*EvalStatus.Diag)[0].second); |
| } |
| HasActiveDiagnostic = false; |
| return OptionalDiagnostic(); |
| } |
| |
| OptionalDiagnostic Diag(const Expr *E, diag::kind DiagId |
| = diag::note_invalid_subexpr_in_const_expr, |
| unsigned ExtraNotes = 0) { |
| if (EvalStatus.Diag) |
| return Diag(E->getExprLoc(), DiagId, ExtraNotes); |
| HasActiveDiagnostic = false; |
| return OptionalDiagnostic(); |
| } |
| |
| /// Diagnose that the evaluation does not produce a C++11 core constant |
| /// expression. |
| /// |
| /// FIXME: Stop evaluating if we're in EM_ConstantExpression or |
| /// EM_PotentialConstantExpression mode and we produce one of these. |
| template<typename LocArg> |
| OptionalDiagnostic CCEDiag(LocArg Loc, diag::kind DiagId |
| = diag::note_invalid_subexpr_in_const_expr, |
| unsigned ExtraNotes = 0) { |
| // Don't override a previous diagnostic. Don't bother collecting |
| // diagnostics if we're evaluating for overflow. |
| if (!EvalStatus.Diag || !EvalStatus.Diag->empty()) { |
| HasActiveDiagnostic = false; |
| return OptionalDiagnostic(); |
| } |
| return Diag(Loc, DiagId, ExtraNotes); |
| } |
| |
| /// Add a note to a prior diagnostic. |
| OptionalDiagnostic Note(SourceLocation Loc, diag::kind DiagId) { |
| if (!HasActiveDiagnostic) |
| return OptionalDiagnostic(); |
| return OptionalDiagnostic(&addDiag(Loc, DiagId)); |
| } |
| |
| /// Add a stack of notes to a prior diagnostic. |
| void addNotes(ArrayRef<PartialDiagnosticAt> Diags) { |
| if (HasActiveDiagnostic) { |
| EvalStatus.Diag->insert(EvalStatus.Diag->end(), |
| Diags.begin(), Diags.end()); |
| } |
| } |
| |
| /// Should we continue evaluation after encountering a side-effect that we |
| /// couldn't model? |
| bool keepEvaluatingAfterSideEffect() { |
| switch (EvalMode) { |
| case EM_PotentialConstantExpression: |
| case EM_EvaluateForOverflow: |
| case EM_IgnoreSideEffects: |
| return true; |
| |
| case EM_ConstantExpression: |
| case EM_ConstantFold: |
| return false; |
| } |
| llvm_unreachable("Missed EvalMode case"); |
| } |
| |
| /// Note that we have had a side-effect, and determine whether we should |
| /// keep evaluating. |
| bool noteSideEffect() { |
| EvalStatus.HasSideEffects = true; |
| return keepEvaluatingAfterSideEffect(); |
| } |
| |
| /// Should we continue evaluation as much as possible after encountering a |
| /// construct which can't be reduced to a value? |
| bool keepEvaluatingAfterFailure() { |
| if (!StepsLeft) |
| return false; |
| |
| switch (EvalMode) { |
| case EM_PotentialConstantExpression: |
| case EM_EvaluateForOverflow: |
| return true; |
| |
| case EM_ConstantExpression: |
| case EM_ConstantFold: |
| case EM_IgnoreSideEffects: |
| return false; |
| } |
| llvm_unreachable("Missed EvalMode case"); |
| } |
| }; |
| |
| /// Object used to treat all foldable expressions as constant expressions. |
| struct FoldConstant { |
| EvalInfo &Info; |
| bool Enabled; |
| bool HadNoPriorDiags; |
| EvalInfo::EvaluationMode OldMode; |
| |
| explicit FoldConstant(EvalInfo &Info, bool Enabled) |
| : Info(Info), |
| Enabled(Enabled), |
| HadNoPriorDiags(Info.EvalStatus.Diag && |
| Info.EvalStatus.Diag->empty() && |
| !Info.EvalStatus.HasSideEffects), |
| OldMode(Info.EvalMode) { |
| if (Enabled && Info.EvalMode == EvalInfo::EM_ConstantExpression) |
| Info.EvalMode = EvalInfo::EM_ConstantFold; |
| } |
| void keepDiagnostics() { Enabled = false; } |
| ~FoldConstant() { |
| if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() && |
| !Info.EvalStatus.HasSideEffects) |
| Info.EvalStatus.Diag->clear(); |
| Info.EvalMode = OldMode; |
| } |
| }; |
| |
| /// RAII object used to suppress diagnostics and side-effects from a |
| /// speculative evaluation. |
| class SpeculativeEvaluationRAII { |
| EvalInfo &Info; |
| Expr::EvalStatus Old; |
| |
| public: |
| SpeculativeEvaluationRAII(EvalInfo &Info, |
| SmallVectorImpl<PartialDiagnosticAt> *NewDiag = 0) |
| : Info(Info), Old(Info.EvalStatus) { |
| Info.EvalStatus.Diag = NewDiag; |
| // If we're speculatively evaluating, we may have skipped over some |
| // evaluations and missed out a side effect. |
| Info.EvalStatus.HasSideEffects = true; |
| } |
| ~SpeculativeEvaluationRAII() { |
| Info.EvalStatus = Old; |
| } |
| }; |
| |
| /// RAII object wrapping a full-expression or block scope, and handling |
| /// the ending of the lifetime of temporaries created within it. |
| template<bool IsFullExpression> |
| class ScopeRAII { |
| EvalInfo &Info; |
| unsigned OldStackSize; |
| public: |
| ScopeRAII(EvalInfo &Info) |
| : Info(Info), OldStackSize(Info.CleanupStack.size()) {} |
| ~ScopeRAII() { |
| // Body moved to a static method to encourage the compiler to inline away |
| // instances of this class. |
| cleanup(Info, OldStackSize); |
| } |
| private: |
| static void cleanup(EvalInfo &Info, unsigned OldStackSize) { |
| unsigned NewEnd = OldStackSize; |
| for (unsigned I = OldStackSize, N = Info.CleanupStack.size(); |
| I != N; ++I) { |
| if (IsFullExpression && Info.CleanupStack[I].isLifetimeExtended()) { |
| // Full-expression cleanup of a lifetime-extended temporary: nothing |
| // to do, just move this cleanup to the right place in the stack. |
| std::swap(Info.CleanupStack[I], Info.CleanupStack[NewEnd]); |
| ++NewEnd; |
| } else { |
| // End the lifetime of the object. |
| Info.CleanupStack[I].endLifetime(); |
| } |
| } |
| Info.CleanupStack.erase(Info.CleanupStack.begin() + NewEnd, |
| Info.CleanupStack.end()); |
| } |
| }; |
| typedef ScopeRAII<false> BlockScopeRAII; |
| typedef ScopeRAII<true> FullExpressionRAII; |
| } |
| |
| bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E, |
| CheckSubobjectKind CSK) { |
| if (Invalid) |
| return false; |
| if (isOnePastTheEnd()) { |
| Info.CCEDiag(E, diag::note_constexpr_past_end_subobject) |
| << CSK; |
| setInvalid(); |
| return false; |
| } |
| return true; |
| } |
| |
| void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info, |
| const Expr *E, uint64_t N) { |
| if (MostDerivedPathLength == Entries.size() && MostDerivedArraySize) |
| Info.CCEDiag(E, diag::note_constexpr_array_index) |
| << static_cast<int>(N) << /*array*/ 0 |
| << static_cast<unsigned>(MostDerivedArraySize); |
| else |
| Info.CCEDiag(E, diag::note_constexpr_array_index) |
| << static_cast<int>(N) << /*non-array*/ 1; |
| setInvalid(); |
| } |
| |
| CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, |
| const FunctionDecl *Callee, const LValue *This, |
| APValue *Arguments) |
| : Info(Info), Caller(Info.CurrentCall), CallLoc(CallLoc), Callee(Callee), |
| Index(Info.NextCallIndex++), This(This), Arguments(Arguments) { |
| Info.CurrentCall = this; |
| ++Info.CallStackDepth; |
| } |
| |
| CallStackFrame::~CallStackFrame() { |
| assert(Info.CurrentCall == this && "calls retired out of order"); |
| --Info.CallStackDepth; |
| Info.CurrentCall = Caller; |
| } |
| |
| APValue &CallStackFrame::createTemporary(const void *Key, |
| bool IsLifetimeExtended) { |
| APValue &Result = Temporaries[Key]; |
| assert(Result.isUninit() && "temporary created multiple times"); |
| Info.CleanupStack.push_back(Cleanup(&Result, IsLifetimeExtended)); |
| return Result; |
| } |
| |
| static void describeCall(CallStackFrame *Frame, raw_ostream &Out); |
| |
| void EvalInfo::addCallStack(unsigned Limit) { |
| // Determine which calls to skip, if any. |
| unsigned ActiveCalls = CallStackDepth - 1; |
| unsigned SkipStart = ActiveCalls, SkipEnd = SkipStart; |
| if (Limit && Limit < ActiveCalls) { |
| SkipStart = Limit / 2 + Limit % 2; |
| SkipEnd = ActiveCalls - Limit / 2; |
| } |
| |
| // Walk the call stack and add the diagnostics. |
| unsigned CallIdx = 0; |
| for (CallStackFrame *Frame = CurrentCall; Frame != &BottomFrame; |
| Frame = Frame->Caller, ++CallIdx) { |
| // Skip this call? |
| if (CallIdx >= SkipStart && CallIdx < SkipEnd) { |
| if (CallIdx == SkipStart) { |
| // Note that we're skipping calls. |
| addDiag(Frame->CallLoc, diag::note_constexpr_calls_suppressed) |
| << unsigned(ActiveCalls - Limit); |
| } |
| continue; |
| } |
| |
| SmallVector<char, 128> Buffer; |
| llvm::raw_svector_ostream Out(Buffer); |
| describeCall(Frame, Out); |
| addDiag(Frame->CallLoc, diag::note_constexpr_call_here) << Out.str(); |
| } |
| } |
| |
| namespace { |
| struct ComplexValue { |
| private: |
| bool IsInt; |
| |
| public: |
| APSInt IntReal, IntImag; |
| APFloat FloatReal, FloatImag; |
| |
| ComplexValue() : FloatReal(APFloat::Bogus), FloatImag(APFloat::Bogus) {} |
| |
| void makeComplexFloat() { IsInt = false; } |
| bool isComplexFloat() const { return !IsInt; } |
| APFloat &getComplexFloatReal() { return FloatReal; } |
| APFloat &getComplexFloatImag() { return FloatImag; } |
| |
| void makeComplexInt() { IsInt = true; } |
| bool isComplexInt() const { return IsInt; } |
| APSInt &getComplexIntReal() { return IntReal; } |
| APSInt &getComplexIntImag() { return IntImag; } |
| |
| void moveInto(APValue &v) const { |
| if (isComplexFloat()) |
| v = APValue(FloatReal, FloatImag); |
| else |
| v = APValue(IntReal, IntImag); |
| } |
| void setFrom(const APValue &v) { |
| assert(v.isComplexFloat() || v.isComplexInt()); |
| if (v.isComplexFloat()) { |
| makeComplexFloat(); |
| FloatReal = v.getComplexFloatReal(); |
| FloatImag = v.getComplexFloatImag(); |
| } else { |
| makeComplexInt(); |
| IntReal = v.getComplexIntReal(); |
| IntImag = v.getComplexIntImag(); |
| } |
| } |
| }; |
| |
| struct LValue { |
| APValue::LValueBase Base; |
| CharUnits Offset; |
| unsigned CallIndex; |
| SubobjectDesignator Designator; |
| |
| const APValue::LValueBase getLValueBase() const { return Base; } |
| CharUnits &getLValueOffset() { return Offset; } |
| const CharUnits &getLValueOffset() const { return Offset; } |
| unsigned getLValueCallIndex() const { return CallIndex; } |
| SubobjectDesignator &getLValueDesignator() { return Designator; } |
| const SubobjectDesignator &getLValueDesignator() const { return Designator;} |
| |
| void moveInto(APValue &V) const { |
| if (Designator.Invalid) |
| V = APValue(Base, Offset, APValue::NoLValuePath(), CallIndex); |
| else |
| V = APValue(Base, Offset, Designator.Entries, |
| Designator.IsOnePastTheEnd, CallIndex); |
| } |
| void setFrom(ASTContext &Ctx, const APValue &V) { |
| assert(V.isLValue()); |
| Base = V.getLValueBase(); |
| Offset = V.getLValueOffset(); |
| CallIndex = V.getLValueCallIndex(); |
| Designator = SubobjectDesignator(Ctx, V); |
| } |
| |
| void set(APValue::LValueBase B, unsigned I = 0) { |
| Base = B; |
| Offset = CharUnits::Zero(); |
| CallIndex = I; |
| Designator = SubobjectDesignator(getType(B)); |
| } |
| |
| // Check that this LValue is not based on a null pointer. If it is, produce |
| // a diagnostic and mark the designator as invalid. |
| bool checkNullPointer(EvalInfo &Info, const Expr *E, |
| CheckSubobjectKind CSK) { |
| if (Designator.Invalid) |
| return false; |
| if (!Base) { |
| Info.CCEDiag(E, diag::note_constexpr_null_subobject) |
| << CSK; |
| Designator.setInvalid(); |
| return false; |
| } |
| return true; |
| } |
| |
| // Check this LValue refers to an object. If not, set the designator to be |
| // invalid and emit a diagnostic. |
| bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) { |
| // Outside C++11, do not build a designator referring to a subobject of |
| // any object: we won't use such a designator for anything. |
| if (!Info.getLangOpts().CPlusPlus11) |
| Designator.setInvalid(); |
| return checkNullPointer(Info, E, CSK) && |
| Designator.checkSubobject(Info, E, CSK); |
| } |
| |
| void addDecl(EvalInfo &Info, const Expr *E, |
| const Decl *D, bool Virtual = false) { |
| if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base)) |
| Designator.addDeclUnchecked(D, Virtual); |
| } |
| void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) { |
| if (checkSubobject(Info, E, CSK_ArrayToPointer)) |
| Designator.addArrayUnchecked(CAT); |
| } |
| void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) { |
| if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real)) |
| Designator.addComplexUnchecked(EltTy, Imag); |
| } |
| void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) { |
| if (checkNullPointer(Info, E, CSK_ArrayIndex)) |
| Designator.adjustIndex(Info, E, N); |
| } |
| }; |
| |
| struct MemberPtr { |
| MemberPtr() {} |
| explicit MemberPtr(const ValueDecl *Decl) : |
| DeclAndIsDerivedMember(Decl, false), Path() {} |
| |
| /// The member or (direct or indirect) field referred to by this member |
| /// pointer, or 0 if this is a null member pointer. |
| const ValueDecl *getDecl() const { |
| return DeclAndIsDerivedMember.getPointer(); |
| } |
| /// Is this actually a member of some type derived from the relevant class? |
| bool isDerivedMember() const { |
| return DeclAndIsDerivedMember.getInt(); |
| } |
| /// Get the class which the declaration actually lives in. |
| const CXXRecordDecl *getContainingRecord() const { |
| return cast<CXXRecordDecl>( |
| DeclAndIsDerivedMember.getPointer()->getDeclContext()); |
| } |
| |
| void moveInto(APValue &V) const { |
| V = APValue(getDecl(), isDerivedMember(), Path); |
| } |
| void setFrom(const APValue &V) { |
| assert(V.isMemberPointer()); |
| DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl()); |
| DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember()); |
| Path.clear(); |
| ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath(); |
| Path.insert(Path.end(), P.begin(), P.end()); |
| } |
| |
| /// DeclAndIsDerivedMember - The member declaration, and a flag indicating |
| /// whether the member is a member of some class derived from the class type |
| /// of the member pointer. |
| llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember; |
| /// Path - The path of base/derived classes from the member declaration's |
| /// class (exclusive) to the class type of the member pointer (inclusive). |
| SmallVector<const CXXRecordDecl*, 4> Path; |
| |
| /// Perform a cast towards the class of the Decl (either up or down the |
| /// hierarchy). |
| bool castBack(const CXXRecordDecl *Class) { |
| assert(!Path.empty()); |
| const CXXRecordDecl *Expected; |
| if (Path.size() >= 2) |
| Expected = Path[Path.size() - 2]; |
| else |
| Expected = getContainingRecord(); |
| if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) { |
| // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*), |
| // if B does not contain the original member and is not a base or |
| // derived class of the class containing the original member, the result |
| // of the cast is undefined. |
| // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to |
| // (D::*). We consider that to be a language defect. |
| return false; |
| } |
| Path.pop_back(); |
| return true; |
| } |
| /// Perform a base-to-derived member pointer cast. |
| bool castToDerived(const CXXRecordDecl *Derived) { |
| if (!getDecl()) |
| return true; |
| if (!isDerivedMember()) { |
| Path.push_back(Derived); |
| return true; |
| } |
| if (!castBack(Derived)) |
| return false; |
| if (Path.empty()) |
| DeclAndIsDerivedMember.setInt(false); |
| return true; |
| } |
| /// Perform a derived-to-base member pointer cast. |
| bool castToBase(const CXXRecordDecl *Base) { |
| if (!getDecl()) |
| return true; |
| if (Path.empty()) |
| DeclAndIsDerivedMember.setInt(true); |
| if (isDerivedMember()) { |
| Path.push_back(Base); |
| return true; |
| } |
| return castBack(Base); |
| } |
| }; |
| |
| /// Compare two member pointers, which are assumed to be of the same type. |
| static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) { |
| if (!LHS.getDecl() || !RHS.getDecl()) |
| return !LHS.getDecl() && !RHS.getDecl(); |
| if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl()) |
| return false; |
| return LHS.Path == RHS.Path; |
| } |
| } |
| |
| static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E); |
| static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, |
| const LValue &This, const Expr *E, |
| bool AllowNonLiteralTypes = false); |
| static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info); |
| static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info); |
| static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, |
| EvalInfo &Info); |
| static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info); |
| static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info); |
| static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result, |
| EvalInfo &Info); |
| static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info); |
| static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info); |
| static bool EvaluateAtomic(const Expr *E, APValue &Result, EvalInfo &Info); |
| |
| //===----------------------------------------------------------------------===// |
| // Misc utilities |
| //===----------------------------------------------------------------------===// |
| |
| /// Produce a string describing the given constexpr call. |
| static void describeCall(CallStackFrame *Frame, raw_ostream &Out) { |
| unsigned ArgIndex = 0; |
| bool IsMemberCall = isa<CXXMethodDecl>(Frame->Callee) && |
| !isa<CXXConstructorDecl>(Frame->Callee) && |
| cast<CXXMethodDecl>(Frame->Callee)->isInstance(); |
| |
| if (!IsMemberCall) |
| Out << *Frame->Callee << '('; |
| |
| if (Frame->This && IsMemberCall) { |
| APValue Val; |
| Frame->This->moveInto(Val); |
| Val.printPretty(Out, Frame->Info.Ctx, |
| Frame->This->Designator.MostDerivedType); |
| // FIXME: Add parens around Val if needed. |
| Out << "->" << *Frame->Callee << '('; |
| IsMemberCall = false; |
| } |
| |
| for (FunctionDecl::param_const_iterator I = Frame->Callee->param_begin(), |
| E = Frame->Callee->param_end(); I != E; ++I, ++ArgIndex) { |
| if (ArgIndex > (unsigned)IsMemberCall) |
| Out << ", "; |
| |
| const ParmVarDecl *Param = *I; |
| const APValue &Arg = Frame->Arguments[ArgIndex]; |
| Arg.printPretty(Out, Frame->Info.Ctx, Param->getType()); |
| |
| if (ArgIndex == 0 && IsMemberCall) |
| Out << "->" << *Frame->Callee << '('; |
| } |
| |
| Out << ')'; |
| } |
| |
| /// Evaluate an expression to see if it had side-effects, and discard its |
| /// result. |
| /// \return \c true if the caller should keep evaluating. |
| static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) { |
| APValue Scratch; |
| if (!Evaluate(Scratch, Info, E)) |
| // We don't need the value, but we might have skipped a side effect here. |
| return Info.noteSideEffect(); |
| return true; |
| } |
| |
| /// Sign- or zero-extend a value to 64 bits. If it's already 64 bits, just |
| /// return its existing value. |
| static int64_t getExtValue(const APSInt &Value) { |
| return Value.isSigned() ? Value.getSExtValue() |
| : static_cast<int64_t>(Value.getZExtValue()); |
| } |
| |
| /// Should this call expression be treated as a string literal? |
| static bool IsStringLiteralCall(const CallExpr *E) { |
| unsigned Builtin = E->isBuiltinCall(); |
| return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString || |
| Builtin == Builtin::BI__builtin___NSStringMakeConstantString); |
| } |
| |
| static bool IsGlobalLValue(APValue::LValueBase B) { |
| // C++11 [expr.const]p3 An address constant expression is a prvalue core |
| // constant expression of pointer type that evaluates to... |
| |
| // ... a null pointer value, or a prvalue core constant expression of type |
| // std::nullptr_t. |
| if (!B) return true; |
| |
| if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { |
| // ... the address of an object with static storage duration, |
| if (const VarDecl *VD = dyn_cast<VarDecl>(D)) |
| return VD->hasGlobalStorage(); |
| // ... the address of a function, |
| return isa<FunctionDecl>(D); |
| } |
| |
| const Expr *E = B.get<const Expr*>(); |
| switch (E->getStmtClass()) { |
| default: |
| return false; |
| case Expr::CompoundLiteralExprClass: { |
| const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E); |
| return CLE->isFileScope() && CLE->isLValue(); |
| } |
| case Expr::MaterializeTemporaryExprClass: |
| // A materialized temporary might have been lifetime-extended to static |
| // storage duration. |
| return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static; |
| // A string literal has static storage duration. |
| case Expr::StringLiteralClass: |
| case Expr::PredefinedExprClass: |
| case Expr::ObjCStringLiteralClass: |
| case Expr::ObjCEncodeExprClass: |
| case Expr::CXXTypeidExprClass: |
| case Expr::CXXUuidofExprClass: |
| return true; |
| case Expr::CallExprClass: |
| return IsStringLiteralCall(cast<CallExpr>(E)); |
| // For GCC compatibility, &&label has static storage duration. |
| case Expr::AddrLabelExprClass: |
| return true; |
| // A Block literal expression may be used as the initialization value for |
| // Block variables at global or local static scope. |
| case Expr::BlockExprClass: |
| return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures(); |
| case Expr::ImplicitValueInitExprClass: |
| // FIXME: |
| // We can never form an lvalue with an implicit value initialization as its |
| // base through expression evaluation, so these only appear in one case: the |
| // implicit variable declaration we invent when checking whether a constexpr |
| // constructor can produce a constant expression. We must assume that such |
| // an expression might be a global lvalue. |
| return true; |
| } |
| } |
| |
| static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) { |
| assert(Base && "no location for a null lvalue"); |
| const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); |
| if (VD) |
| Info.Note(VD->getLocation(), diag::note_declared_at); |
| else |
| Info.Note(Base.get<const Expr*>()->getExprLoc(), |
| diag::note_constexpr_temporary_here); |
| } |
| |
| /// Check that this reference or pointer core constant expression is a valid |
| /// value for an address or reference constant expression. Return true if we |
| /// can fold this expression, whether or not it's a constant expression. |
| static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc, |
| QualType Type, const LValue &LVal) { |
| bool IsReferenceType = Type->isReferenceType(); |
| |
| APValue::LValueBase Base = LVal.getLValueBase(); |
| const SubobjectDesignator &Designator = LVal.getLValueDesignator(); |
| |
| // Check that the object is a global. Note that the fake 'this' object we |
| // manufacture when checking potential constant expressions is conservatively |
| // assumed to be global here. |
| if (!IsGlobalLValue(Base)) { |
| if (Info.getLangOpts().CPlusPlus11) { |
| const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); |
| Info.Diag(Loc, diag::note_constexpr_non_global, 1) |
| << IsReferenceType << !Designator.Entries.empty() |
| << !!VD << VD; |
| NoteLValueLocation(Info, Base); |
| } else { |
| Info.Diag(Loc); |
| } |
| // Don't allow references to temporaries to escape. |
| return false; |
| } |
| assert((Info.checkingPotentialConstantExpression() || |
| LVal.getLValueCallIndex() == 0) && |
| "have call index for global lvalue"); |
| |
| // Check if this is a thread-local variable. |
| if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) { |
| if (const VarDecl *Var = dyn_cast<const VarDecl>(VD)) { |
| if (Var->getTLSKind()) |
| return false; |
| } |
| } |
| |
| // Allow address constant expressions to be past-the-end pointers. This is |
| // an extension: the standard requires them to point to an object. |
| if (!IsReferenceType) |
| return true; |
| |
| // A reference constant expression must refer to an object. |
| if (!Base) { |
| // FIXME: diagnostic |
| Info.CCEDiag(Loc); |
| return true; |
| } |
| |
| // Does this refer one past the end of some object? |
| if (Designator.isOnePastTheEnd()) { |
| const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); |
| Info.Diag(Loc, diag::note_constexpr_past_end, 1) |
| << !Designator.Entries.empty() << !!VD << VD; |
| NoteLValueLocation(Info, Base); |
| } |
| |
| return true; |
| } |
| |
| /// Check that this core constant expression is of literal type, and if not, |
| /// produce an appropriate diagnostic. |
| static bool CheckLiteralType(EvalInfo &Info, const Expr *E, |
| const LValue *This = 0) { |
| if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx)) |
| return true; |
| |
| // C++1y: A constant initializer for an object o [...] may also invoke |
| // constexpr constructors for o and its subobjects even if those objects |
| // are of non-literal class types. |
| if (Info.getLangOpts().CPlusPlus1y && This && |
| Info.EvaluatingDecl == This->getLValueBase()) |
| return true; |
| |
| // Prvalue constant expressions must be of literal types. |
| if (Info.getLangOpts().CPlusPlus11) |
| Info.Diag(E, diag::note_constexpr_nonliteral) |
| << E->getType(); |
| else |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| return false; |
| } |
| |
| /// Check that this core constant expression value is a valid value for a |
| /// constant expression. If not, report an appropriate diagnostic. Does not |
| /// check that the expression is of literal type. |
| static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc, |
| QualType Type, const APValue &Value) { |
| if (Value.isUninit()) { |
| Info.Diag(DiagLoc, diag::note_constexpr_uninitialized) |
| << true << Type; |
| return false; |
| } |
| |
| // Core issue 1454: For a literal constant expression of array or class type, |
| // each subobject of its value shall have been initialized by a constant |
| // expression. |
| if (Value.isArray()) { |
| QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType(); |
| for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) { |
| if (!CheckConstantExpression(Info, DiagLoc, EltTy, |
| Value.getArrayInitializedElt(I))) |
| return false; |
| } |
| if (!Value.hasArrayFiller()) |
| return true; |
| return CheckConstantExpression(Info, DiagLoc, EltTy, |
| Value.getArrayFiller()); |
| } |
| if (Value.isUnion() && Value.getUnionField()) { |
| return CheckConstantExpression(Info, DiagLoc, |
| Value.getUnionField()->getType(), |
| Value.getUnionValue()); |
| } |
| if (Value.isStruct()) { |
| RecordDecl *RD = Type->castAs<RecordType>()->getDecl(); |
| if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) { |
| unsigned BaseIndex = 0; |
| for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(), |
| End = CD->bases_end(); I != End; ++I, ++BaseIndex) { |
| if (!CheckConstantExpression(Info, DiagLoc, I->getType(), |
| Value.getStructBase(BaseIndex))) |
| return false; |
| } |
| } |
| for (RecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end(); |
| I != E; ++I) { |
| if (!CheckConstantExpression(Info, DiagLoc, I->getType(), |
| Value.getStructField(I->getFieldIndex()))) |
| return false; |
| } |
| } |
| |
| if (Value.isLValue()) { |
| LValue LVal; |
| LVal.setFrom(Info.Ctx, Value); |
| return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal); |
| } |
| |
| // Everything else is fine. |
| return true; |
| } |
| |
| const ValueDecl *GetLValueBaseDecl(const LValue &LVal) { |
| return LVal.Base.dyn_cast<const ValueDecl*>(); |
| } |
| |
| static bool IsLiteralLValue(const LValue &Value) { |
| if (Value.CallIndex) |
| return false; |
| const Expr *E = Value.Base.dyn_cast<const Expr*>(); |
| return E && !isa<MaterializeTemporaryExpr>(E); |
| } |
| |
| static bool IsWeakLValue(const LValue &Value) { |
| const ValueDecl *Decl = GetLValueBaseDecl(Value); |
| return Decl && Decl->isWeak(); |
| } |
| |
| static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) { |
| // A null base expression indicates a null pointer. These are always |
| // evaluatable, and they are false unless the offset is zero. |
| if (!Value.getLValueBase()) { |
| Result = !Value.getLValueOffset().isZero(); |
| return true; |
| } |
| |
| // We have a non-null base. These are generally known to be true, but if it's |
| // a weak declaration it can be null at runtime. |
| Result = true; |
| const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>(); |
| return !Decl || !Decl->isWeak(); |
| } |
| |
| static bool HandleConversionToBool(const APValue &Val, bool &Result) { |
| switch (Val.getKind()) { |
| case APValue::Uninitialized: |
| return false; |
| case APValue::Int: |
| Result = Val.getInt().getBoolValue(); |
| return true; |
| case APValue::Float: |
| Result = !Val.getFloat().isZero(); |
| return true; |
| case APValue::ComplexInt: |
| Result = Val.getComplexIntReal().getBoolValue() || |
| Val.getComplexIntImag().getBoolValue(); |
| return true; |
| case APValue::ComplexFloat: |
| Result = !Val.getComplexFloatReal().isZero() || |
| !Val.getComplexFloatImag().isZero(); |
| return true; |
| case APValue::LValue: |
| return EvalPointerValueAsBool(Val, Result); |
| case APValue::MemberPointer: |
| Result = Val.getMemberPointerDecl(); |
| return true; |
| case APValue::Vector: |
| case APValue::Array: |
| case APValue::Struct: |
| case APValue::Union: |
| case APValue::AddrLabelDiff: |
| return false; |
| } |
| |
| llvm_unreachable("unknown APValue kind"); |
| } |
| |
| static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result, |
| EvalInfo &Info) { |
| assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition"); |
| APValue Val; |
| if (!Evaluate(Val, Info, E)) |
| return false; |
| return HandleConversionToBool(Val, Result); |
| } |
| |
| template<typename T> |
| static void HandleOverflow(EvalInfo &Info, const Expr *E, |
| const T &SrcValue, QualType DestType) { |
| Info.CCEDiag(E, diag::note_constexpr_overflow) |
| << SrcValue << DestType; |
| } |
| |
| static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E, |
| QualType SrcType, const APFloat &Value, |
| QualType DestType, APSInt &Result) { |
| unsigned DestWidth = Info.Ctx.getIntWidth(DestType); |
| // Determine whether we are converting to unsigned or signed. |
| bool DestSigned = DestType->isSignedIntegerOrEnumerationType(); |
| |
| Result = APSInt(DestWidth, !DestSigned); |
| bool ignored; |
| if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored) |
| & APFloat::opInvalidOp) |
| HandleOverflow(Info, E, Value, DestType); |
| return true; |
| } |
| |
| static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E, |
| QualType SrcType, QualType DestType, |
| APFloat &Result) { |
| APFloat Value = Result; |
| bool ignored; |
| if (Result.convert(Info.Ctx.getFloatTypeSemantics(DestType), |
| APFloat::rmNearestTiesToEven, &ignored) |
| & APFloat::opOverflow) |
| HandleOverflow(Info, E, Value, DestType); |
| return true; |
| } |
| |
| static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E, |
| QualType DestType, QualType SrcType, |
| APSInt &Value) { |
| unsigned DestWidth = Info.Ctx.getIntWidth(DestType); |
| APSInt Result = Value; |
| // Figure out if this is a truncate, extend or noop cast. |
| // If the input is signed, do a sign extend, noop, or truncate. |
| Result = Result.extOrTrunc(DestWidth); |
| Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType()); |
| return Result; |
| } |
| |
| static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E, |
| QualType SrcType, const APSInt &Value, |
| QualType DestType, APFloat &Result) { |
| Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1); |
| if (Result.convertFromAPInt(Value, Value.isSigned(), |
| APFloat::rmNearestTiesToEven) |
| & APFloat::opOverflow) |
| HandleOverflow(Info, E, Value, DestType); |
| return true; |
| } |
| |
| static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E, |
| APValue &Value, const FieldDecl *FD) { |
| assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield"); |
| |
| if (!Value.isInt()) { |
| // Trying to store a pointer-cast-to-integer into a bitfield. |
| // FIXME: In this case, we should provide the diagnostic for casting |
| // a pointer to an integer. |
| assert(Value.isLValue() && "integral value neither int nor lvalue?"); |
| Info.Diag(E); |
| return false; |
| } |
| |
| APSInt &Int = Value.getInt(); |
| unsigned OldBitWidth = Int.getBitWidth(); |
| unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx); |
| if (NewBitWidth < OldBitWidth) |
| Int = Int.trunc(NewBitWidth).extend(OldBitWidth); |
| return true; |
| } |
| |
| static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E, |
| llvm::APInt &Res) { |
| APValue SVal; |
| if (!Evaluate(SVal, Info, E)) |
| return false; |
| if (SVal.isInt()) { |
| Res = SVal.getInt(); |
| return true; |
| } |
| if (SVal.isFloat()) { |
| Res = SVal.getFloat().bitcastToAPInt(); |
| return true; |
| } |
| if (SVal.isVector()) { |
| QualType VecTy = E->getType(); |
| unsigned VecSize = Info.Ctx.getTypeSize(VecTy); |
| QualType EltTy = VecTy->castAs<VectorType>()->getElementType(); |
| unsigned EltSize = Info.Ctx.getTypeSize(EltTy); |
| bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); |
| Res = llvm::APInt::getNullValue(VecSize); |
| for (unsigned i = 0; i < SVal.getVectorLength(); i++) { |
| APValue &Elt = SVal.getVectorElt(i); |
| llvm::APInt EltAsInt; |
| if (Elt.isInt()) { |
| EltAsInt = Elt.getInt(); |
| } else if (Elt.isFloat()) { |
| EltAsInt = Elt.getFloat().bitcastToAPInt(); |
| } else { |
| // Don't try to handle vectors of anything other than int or float |
| // (not sure if it's possible to hit this case). |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| return false; |
| } |
| unsigned BaseEltSize = EltAsInt.getBitWidth(); |
| if (BigEndian) |
| Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize); |
| else |
| Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize); |
| } |
| return true; |
| } |
| // Give up if the input isn't an int, float, or vector. For example, we |
| // reject "(v4i16)(intptr_t)&a". |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| return false; |
| } |
| |
| /// Perform the given integer operation, which is known to need at most BitWidth |
| /// bits, and check for overflow in the original type (if that type was not an |
| /// unsigned type). |
| template<typename Operation> |
| static APSInt CheckedIntArithmetic(EvalInfo &Info, const Expr *E, |
| const APSInt &LHS, const APSInt &RHS, |
| unsigned BitWidth, Operation Op) { |
| if (LHS.isUnsigned()) |
| return Op(LHS, RHS); |
| |
| APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false); |
| APSInt Result = Value.trunc(LHS.getBitWidth()); |
| if (Result.extend(BitWidth) != Value) { |
| if (Info.checkingForOverflow()) |
| Info.Ctx.getDiagnostics().Report(E->getExprLoc(), |
| diag::warn_integer_constant_overflow) |
| << Result.toString(10) << E->getType(); |
| else |
| HandleOverflow(Info, E, Value, E->getType()); |
| } |
| return Result; |
| } |
| |
| /// Perform the given binary integer operation. |
| static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS, |
| BinaryOperatorKind Opcode, APSInt RHS, |
| APSInt &Result) { |
| switch (Opcode) { |
| default: |
| Info.Diag(E); |
| return false; |
| case BO_Mul: |
| Result = CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2, |
| std::multiplies<APSInt>()); |
| return true; |
| case BO_Add: |
| Result = CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1, |
| std::plus<APSInt>()); |
| return true; |
| case BO_Sub: |
| Result = CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1, |
| std::minus<APSInt>()); |
| return true; |
| case BO_And: Result = LHS & RHS; return true; |
| case BO_Xor: Result = LHS ^ RHS; return true; |
| case BO_Or: Result = LHS | RHS; return true; |
| case BO_Div: |
| case BO_Rem: |
| if (RHS == 0) { |
| Info.Diag(E, diag::note_expr_divide_by_zero); |
| return false; |
| } |
| // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. |
| if (RHS.isNegative() && RHS.isAllOnesValue() && |
| LHS.isSigned() && LHS.isMinSignedValue()) |
| HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1), E->getType()); |
| Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS); |
| return true; |
| case BO_Shl: { |
| if (Info.getLangOpts().OpenCL) |
| // OpenCL 6.3j: shift values are effectively % word size of LHS. |
| RHS &= APSInt(llvm::APInt(RHS.getBitWidth(), |
| static_cast<uint64_t>(LHS.getBitWidth() - 1)), |
| RHS.isUnsigned()); |
| else if (RHS.isSigned() && RHS.isNegative()) { |
| // During constant-folding, a negative shift is an opposite shift. Such |
| // a shift is not a constant expression. |
| Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; |
| RHS = -RHS; |
| goto shift_right; |
| } |
| shift_left: |
| // C++11 [expr.shift]p1: Shift width must be less than the bit width of |
| // the shifted type. |
| unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); |
| if (SA != RHS) { |
| Info.CCEDiag(E, diag::note_constexpr_large_shift) |
| << RHS << E->getType() << LHS.getBitWidth(); |
| } else if (LHS.isSigned()) { |
| // C++11 [expr.shift]p2: A signed left shift must have a non-negative |
| // operand, and must not overflow the corresponding unsigned type. |
| if (LHS.isNegative()) |
| Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS; |
| else if (LHS.countLeadingZeros() < SA) |
| Info.CCEDiag(E, diag::note_constexpr_lshift_discards); |
| } |
| Result = LHS << SA; |
| return true; |
| } |
| case BO_Shr: { |
| if (Info.getLangOpts().OpenCL) |
| // OpenCL 6.3j: shift values are effectively % word size of LHS. |
| RHS &= APSInt(llvm::APInt(RHS.getBitWidth(), |
| static_cast<uint64_t>(LHS.getBitWidth() - 1)), |
| RHS.isUnsigned()); |
| else if (RHS.isSigned() && RHS.isNegative()) { |
| // During constant-folding, a negative shift is an opposite shift. Such a |
| // shift is not a constant expression. |
| Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; |
| RHS = -RHS; |
| goto shift_left; |
| } |
| shift_right: |
| // C++11 [expr.shift]p1: Shift width must be less than the bit width of the |
| // shifted type. |
| unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); |
| if (SA != RHS) |
| Info.CCEDiag(E, diag::note_constexpr_large_shift) |
| << RHS << E->getType() << LHS.getBitWidth(); |
| Result = LHS >> SA; |
| return true; |
| } |
| |
| case BO_LT: Result = LHS < RHS; return true; |
| case BO_GT: Result = LHS > RHS; return true; |
| case BO_LE: Result = LHS <= RHS; return true; |
| case BO_GE: Result = LHS >= RHS; return true; |
| case BO_EQ: Result = LHS == RHS; return true; |
| case BO_NE: Result = LHS != RHS; return true; |
| } |
| } |
| |
| /// Perform the given binary floating-point operation, in-place, on LHS. |
| static bool handleFloatFloatBinOp(EvalInfo &Info, const Expr *E, |
| APFloat &LHS, BinaryOperatorKind Opcode, |
| const APFloat &RHS) { |
| switch (Opcode) { |
| default: |
| Info.Diag(E); |
| return false; |
| case BO_Mul: |
| LHS.multiply(RHS, APFloat::rmNearestTiesToEven); |
| break; |
| case BO_Add: |
| LHS.add(RHS, APFloat::rmNearestTiesToEven); |
| break; |
| case BO_Sub: |
| LHS.subtract(RHS, APFloat::rmNearestTiesToEven); |
| break; |
| case BO_Div: |
| LHS.divide(RHS, APFloat::rmNearestTiesToEven); |
| break; |
| } |
| |
| if (LHS.isInfinity() || LHS.isNaN()) |
| Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN(); |
| return true; |
| } |
| |
| /// Cast an lvalue referring to a base subobject to a derived class, by |
| /// truncating the lvalue's path to the given length. |
| static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result, |
| const RecordDecl *TruncatedType, |
| unsigned TruncatedElements) { |
| SubobjectDesignator &D = Result.Designator; |
| |
| // Check we actually point to a derived class object. |
| if (TruncatedElements == D.Entries.size()) |
| return true; |
| assert(TruncatedElements >= D.MostDerivedPathLength && |
| "not casting to a derived class"); |
| if (!Result.checkSubobject(Info, E, CSK_Derived)) |
| return false; |
| |
| // Truncate the path to the subobject, and remove any derived-to-base offsets. |
| const RecordDecl *RD = TruncatedType; |
| for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) { |
| if (RD->isInvalidDecl()) return false; |
| const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); |
| const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]); |
| if (isVirtualBaseClass(D.Entries[I])) |
| Result.Offset -= Layout.getVBaseClassOffset(Base); |
| else |
| Result.Offset -= Layout.getBaseClassOffset(Base); |
| RD = Base; |
| } |
| D.Entries.resize(TruncatedElements); |
| return true; |
| } |
| |
| static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj, |
| const CXXRecordDecl *Derived, |
| const CXXRecordDecl *Base, |
| const ASTRecordLayout *RL = 0) { |
| if (!RL) { |
| if (Derived->isInvalidDecl()) return false; |
| RL = &Info.Ctx.getASTRecordLayout(Derived); |
| } |
| |
| Obj.getLValueOffset() += RL->getBaseClassOffset(Base); |
| Obj.addDecl(Info, E, Base, /*Virtual*/ false); |
| return true; |
| } |
| |
| static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj, |
| const CXXRecordDecl *DerivedDecl, |
| const CXXBaseSpecifier *Base) { |
| const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl(); |
| |
| if (!Base->isVirtual()) |
| return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl); |
| |
| SubobjectDesignator &D = Obj.Designator; |
| if (D.Invalid) |
| return false; |
| |
| // Extract most-derived object and corresponding type. |
| DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl(); |
| if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength)) |
| return false; |
| |
| // Find the virtual base class. |
| if (DerivedDecl->isInvalidDecl()) return false; |
| const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl); |
| Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl); |
| Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true); |
| return true; |
| } |
| |
| static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E, |
| QualType Type, LValue &Result) { |
| for (CastExpr::path_const_iterator PathI = E->path_begin(), |
| PathE = E->path_end(); |
| PathI != PathE; ++PathI) { |
| if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(), |
| *PathI)) |
| return false; |
| Type = (*PathI)->getType(); |
| } |
| return true; |
| } |
| |
| /// Update LVal to refer to the given field, which must be a member of the type |
| /// currently described by LVal. |
| static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal, |
| const FieldDecl *FD, |
| const ASTRecordLayout *RL = 0) { |
| if (!RL) { |
| if (FD->getParent()->isInvalidDecl()) return false; |
| RL = &Info.Ctx.getASTRecordLayout(FD->getParent()); |
| } |
| |
| unsigned I = FD->getFieldIndex(); |
| LVal.Offset += Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)); |
| LVal.addDecl(Info, E, FD); |
| return true; |
| } |
| |
| /// Update LVal to refer to the given indirect field. |
| static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E, |
| LValue &LVal, |
| const IndirectFieldDecl *IFD) { |
| for (IndirectFieldDecl::chain_iterator C = IFD->chain_begin(), |
| CE = IFD->chain_end(); C != CE; ++C) |
| if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(*C))) |
| return false; |
| return true; |
| } |
| |
| /// Get the size of the given type in char units. |
| static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc, |
| QualType Type, CharUnits &Size) { |
| // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc |
| // extension. |
| if (Type->isVoidType() || Type->isFunctionType()) { |
| Size = CharUnits::One(); |
| return true; |
| } |
| |
| if (!Type->isConstantSizeType()) { |
| // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2. |
| // FIXME: Better diagnostic. |
| Info.Diag(Loc); |
| return false; |
| } |
| |
| Size = Info.Ctx.getTypeSizeInChars(Type); |
| return true; |
| } |
| |
| /// Update a pointer value to model pointer arithmetic. |
| /// \param Info - Information about the ongoing evaluation. |
| /// \param E - The expression being evaluated, for diagnostic purposes. |
| /// \param LVal - The pointer value to be updated. |
| /// \param EltTy - The pointee type represented by LVal. |
| /// \param Adjustment - The adjustment, in objects of type EltTy, to add. |
| static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E, |
| LValue &LVal, QualType EltTy, |
| int64_t Adjustment) { |
| CharUnits SizeOfPointee; |
| if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee)) |
| return false; |
| |
| // Compute the new offset in the appropriate width. |
| LVal.Offset += Adjustment * SizeOfPointee; |
| LVal.adjustIndex(Info, E, Adjustment); |
| return true; |
| } |
| |
| /// Update an lvalue to refer to a component of a complex number. |
| /// \param Info - Information about the ongoing evaluation. |
| /// \param LVal - The lvalue to be updated. |
| /// \param EltTy - The complex number's component type. |
| /// \param Imag - False for the real component, true for the imaginary. |
| static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E, |
| LValue &LVal, QualType EltTy, |
| bool Imag) { |
| if (Imag) { |
| CharUnits SizeOfComponent; |
| if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent)) |
| return false; |
| LVal.Offset += SizeOfComponent; |
| } |
| LVal.addComplex(Info, E, EltTy, Imag); |
| return true; |
| } |
| |
| /// Try to evaluate the initializer for a variable declaration. |
| /// |
| /// \param Info Information about the ongoing evaluation. |
| /// \param E An expression to be used when printing diagnostics. |
| /// \param VD The variable whose initializer should be obtained. |
| /// \param Frame The frame in which the variable was created. Must be null |
| /// if this variable is not local to the evaluation. |
| /// \param Result Filled in with a pointer to the value of the variable. |
| static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E, |
| const VarDecl *VD, CallStackFrame *Frame, |
| APValue *&Result) { |
| // If this is a parameter to an active constexpr function call, perform |
| // argument substitution. |
| if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) { |
| // Assume arguments of a potential constant expression are unknown |
| // constant expressions. |
| if (Info.checkingPotentialConstantExpression()) |
| return false; |
| if (!Frame || !Frame->Arguments) { |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| return false; |
| } |
| Result = &Frame->Arguments[PVD->getFunctionScopeIndex()]; |
| return true; |
| } |
| |
| // If this is a local variable, dig out its value. |
| if (Frame) { |
| Result = Frame->getTemporary(VD); |
| assert(Result && "missing value for local variable"); |
| return true; |
| } |
| |
| // Dig out the initializer, and use the declaration which it's attached to. |
| const Expr *Init = VD->getAnyInitializer(VD); |
| if (!Init || Init->isValueDependent()) { |
| // If we're checking a potential constant expression, the variable could be |
| // initialized later. |
| if (!Info.checkingPotentialConstantExpression()) |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| return false; |
| } |
| |
| // If we're currently evaluating the initializer of this declaration, use that |
| // in-flight value. |
| if (Info.EvaluatingDecl.dyn_cast<const ValueDecl*>() == VD) { |
| Result = Info.EvaluatingDeclValue; |
| return true; |
| } |
| |
| // Never evaluate the initializer of a weak variable. We can't be sure that |
| // this is the definition which will be used. |
| if (VD->isWeak()) { |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| return false; |
| } |
| |
| // Check that we can fold the initializer. In C++, we will have already done |
| // this in the cases where it matters for conformance. |
| SmallVector<PartialDiagnosticAt, 8> Notes; |
| if (!VD->evaluateValue(Notes)) { |
| Info.Diag(E, diag::note_constexpr_var_init_non_constant, |
| Notes.size() + 1) << VD; |
| Info.Note(VD->getLocation(), diag::note_declared_at); |
| Info.addNotes(Notes); |
| return false; |
| } else if (!VD->checkInitIsICE()) { |
| Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant, |
| Notes.size() + 1) << VD; |
| Info.Note(VD->getLocation(), diag::note_declared_at); |
| Info.addNotes(Notes); |
| } |
| |
| Result = VD->getEvaluatedValue(); |
| return true; |
| } |
| |
| static bool IsConstNonVolatile(QualType T) { |
| Qualifiers Quals = T.getQualifiers(); |
| return Quals.hasConst() && !Quals.hasVolatile(); |
| } |
| |
| /// Get the base index of the given base class within an APValue representing |
| /// the given derived class. |
| static unsigned getBaseIndex(const CXXRecordDecl *Derived, |
| const CXXRecordDecl *Base) { |
| Base = Base->getCanonicalDecl(); |
| unsigned Index = 0; |
| for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(), |
| E = Derived->bases_end(); I != E; ++I, ++Index) { |
| if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base) |
| return Index; |
| } |
| |
| llvm_unreachable("base class missing from derived class's bases list"); |
| } |
| |
| /// Extract the value of a character from a string literal. |
| static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit, |
| uint64_t Index) { |
| // FIXME: Support PredefinedExpr, ObjCEncodeExpr, MakeStringConstant |
| const StringLiteral *S = cast<StringLiteral>(Lit); |
| const ConstantArrayType *CAT = |
| Info.Ctx.getAsConstantArrayType(S->getType()); |
| assert(CAT && "string literal isn't an array"); |
| QualType CharType = CAT->getElementType(); |
| assert(CharType->isIntegerType() && "unexpected character type"); |
| |
| APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), |
| CharType->isUnsignedIntegerType()); |
| if (Index < S->getLength()) |
| Value = S->getCodeUnit(Index); |
| return Value; |
| } |
| |
| // Expand a string literal into an array of characters. |
| static void expandStringLiteral(EvalInfo &Info, const Expr *Lit, |
| APValue &Result) { |
| const StringLiteral *S = cast<StringLiteral>(Lit); |
| const ConstantArrayType *CAT = |
| Info.Ctx.getAsConstantArrayType(S->getType()); |
| assert(CAT && "string literal isn't an array"); |
| QualType CharType = CAT->getElementType(); |
| assert(CharType->isIntegerType() && "unexpected character type"); |
| |
| unsigned Elts = CAT->getSize().getZExtValue(); |
| Result = APValue(APValue::UninitArray(), |
| std::min(S->getLength(), Elts), Elts); |
| APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), |
| CharType->isUnsignedIntegerType()); |
| if (Result.hasArrayFiller()) |
| Result.getArrayFiller() = APValue(Value); |
| for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) { |
| Value = S->getCodeUnit(I); |
| Result.getArrayInitializedElt(I) = APValue(Value); |
| } |
| } |
| |
| // Expand an array so that it has more than Index filled elements. |
| static void expandArray(APValue &Array, unsigned Index) { |
| unsigned Size = Array.getArraySize(); |
| assert(Index < Size); |
| |
| // Always at least double the number of elements for which we store a value. |
| unsigned OldElts = Array.getArrayInitializedElts(); |
| unsigned NewElts = std::max(Index+1, OldElts * 2); |
| NewElts = std::min(Size, std::max(NewElts, 8u)); |
| |
| // Copy the data across. |
| APValue NewValue(APValue::UninitArray(), NewElts, Size); |
| for (unsigned I = 0; I != OldElts; ++I) |
| NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I)); |
| for (unsigned I = OldElts; I != NewElts; ++I) |
| NewValue.getArrayInitializedElt(I) = Array.getArrayFiller(); |
| if (NewValue.hasArrayFiller()) |
| NewValue.getArrayFiller() = Array.getArrayFiller(); |
| Array.swap(NewValue); |
| } |
| |
| /// Kinds of access we can perform on an object, for diagnostics. |
| enum AccessKinds { |
| AK_Read, |
| AK_Assign, |
| AK_Increment, |
| AK_Decrement |
| }; |
| |
| /// A handle to a complete object (an object that is not a subobject of |
| /// another object). |
| struct CompleteObject { |
| /// The value of the complete object. |
| APValue *Value; |
| /// The type of the complete object. |
| QualType Type; |
| |
| CompleteObject() : Value(0) {} |
| CompleteObject(APValue *Value, QualType Type) |
| : Value(Value), Type(Type) { |
| assert(Value && "missing value for complete object"); |
| } |
| |
| LLVM_EXPLICIT operator bool() const { return Value; } |
| }; |
| |
| /// Find the designated sub-object of an rvalue. |
| template<typename SubobjectHandler> |
| typename SubobjectHandler::result_type |
| findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj, |
| const SubobjectDesignator &Sub, SubobjectHandler &handler) { |
| if (Sub.Invalid) |
| // A diagnostic will have already been produced. |
| return handler.failed(); |
| if (Sub.isOnePastTheEnd()) { |
| if (Info.getLangOpts().CPlusPlus11) |
| Info.Diag(E, diag::note_constexpr_access_past_end) |
| << handler.AccessKind; |
| else |
| Info.Diag(E); |
| return handler.failed(); |
| } |
| |
| APValue *O = Obj.Value; |
| QualType ObjType = Obj.Type; |
| const FieldDecl *LastField = 0; |
| |
| // Walk the designator's path to find the subobject. |
| for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) { |
| if (O->isUninit()) { |
| if (!Info.checkingPotentialConstantExpression()) |
| Info.Diag(E, diag::note_constexpr_access_uninit) << handler.AccessKind; |
| return handler.failed(); |
| } |
| |
| if (I == N) { |
| if (!handler.found(*O, ObjType)) |
| return false; |
| |
| // If we modified a bit-field, truncate it to the right width. |
| if (handler.AccessKind != AK_Read && |
| LastField && LastField->isBitField() && |
| !truncateBitfieldValue(Info, E, *O, LastField)) |
| return false; |
| |
| return true; |
| } |
| |
| LastField = 0; |
| if (ObjType->isArrayType()) { |
| // Next subobject is an array element. |
| const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType); |
| assert(CAT && "vla in literal type?"); |
| uint64_t Index = Sub.Entries[I].ArrayIndex; |
| if (CAT->getSize().ule(Index)) { |
| // Note, it should not be possible to form a pointer with a valid |
| // designator which points more than one past the end of the array. |
| if (Info.getLangOpts().CPlusPlus11) |
| Info.Diag(E, diag::note_constexpr_access_past_end) |
| << handler.AccessKind; |
| else |
| Info.Diag(E); |
| return handler.failed(); |
| } |
| |
| ObjType = CAT->getElementType(); |
| |
| // An array object is represented as either an Array APValue or as an |
| // LValue which refers to a string literal. |
| if (O->isLValue()) { |
| assert(I == N - 1 && "extracting subobject of character?"); |
| assert(!O->hasLValuePath() || O->getLValuePath().empty()); |
| if (handler.AccessKind != AK_Read) |
| expandStringLiteral(Info, O->getLValueBase().get<const Expr *>(), |
| *O); |
| else |
| return handler.foundString(*O, ObjType, Index); |
| } |
| |
| if (O->getArrayInitializedElts() > Index) |
| O = &O->getArrayInitializedElt(Index); |
| else if (handler.AccessKind != AK_Read) { |
| expandArray(*O, Index); |
| O = &O->getArrayInitializedElt(Index); |
| } else |
| O = &O->getArrayFiller(); |
| } else if (ObjType->isAnyComplexType()) { |
| // Next subobject is a complex number. |
| uint64_t Index = Sub.Entries[I].ArrayIndex; |
| if (Index > 1) { |
| if (Info.getLangOpts().CPlusPlus11) |
| Info.Diag(E, diag::note_constexpr_access_past_end) |
| << handler.AccessKind; |
| else |
| Info.Diag(E); |
| return handler.failed(); |
| } |
| |
| bool WasConstQualified = ObjType.isConstQualified(); |
| ObjType = ObjType->castAs<ComplexType>()->getElementType(); |
| if (WasConstQualified) |
| ObjType.addConst(); |
| |
| assert(I == N - 1 && "extracting subobject of scalar?"); |
| if (O->isComplexInt()) { |
| return handler.found(Index ? O->getComplexIntImag() |
| : O->getComplexIntReal(), ObjType); |
| } else { |
| assert(O->isComplexFloat()); |
| return handler.found(Index ? O->getComplexFloatImag() |
| : O->getComplexFloatReal(), ObjType); |
| } |
| } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) { |
| if (Field->isMutable() && handler.AccessKind == AK_Read) { |
| Info.Diag(E, diag::note_constexpr_ltor_mutable, 1) |
| << Field; |
| Info.Note(Field->getLocation(), diag::note_declared_at); |
| return handler.failed(); |
| } |
| |
| // Next subobject is a class, struct or union field. |
| RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl(); |
| if (RD->isUnion()) { |
| const FieldDecl *UnionField = O->getUnionField(); |
| if (!UnionField || |
| UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) { |
| Info.Diag(E, diag::note_constexpr_access_inactive_union_member) |
| << handler.AccessKind << Field << !UnionField << UnionField; |
| return handler.failed(); |
| } |
| O = &O->getUnionValue(); |
| } else |
| O = &O->getStructField(Field->getFieldIndex()); |
| |
| bool WasConstQualified = ObjType.isConstQualified(); |
| ObjType = Field->getType(); |
| if (WasConstQualified && !Field->isMutable()) |
| ObjType.addConst(); |
| |
| if (ObjType.isVolatileQualified()) { |
| if (Info.getLangOpts().CPlusPlus) { |
| // FIXME: Include a description of the path to the volatile subobject. |
| Info.Diag(E, diag::note_constexpr_access_volatile_obj, 1) |
| << handler.AccessKind << 2 << Field; |
| Info.Note(Field->getLocation(), diag::note_declared_at); |
| } else { |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| } |
| return handler.failed(); |
| } |
| |
| LastField = Field; |
| } else { |
| // Next subobject is a base class. |
| const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl(); |
| const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]); |
| O = &O->getStructBase(getBaseIndex(Derived, Base)); |
| |
| bool WasConstQualified = ObjType.isConstQualified(); |
| ObjType = Info.Ctx.getRecordType(Base); |
| if (WasConstQualified) |
| ObjType.addConst(); |
| } |
| } |
| } |
| |
| namespace { |
| struct ExtractSubobjectHandler { |
| EvalInfo &Info; |
| APValue &Result; |
| |
| static const AccessKinds AccessKind = AK_Read; |
| |
| typedef bool result_type; |
| bool failed() { return false; } |
| bool found(APValue &Subobj, QualType SubobjType) { |
| Result = Subobj; |
| return true; |
| } |
| bool found(APSInt &Value, QualType SubobjType) { |
| Result = APValue(Value); |
| return true; |
| } |
| bool found(APFloat &Value, QualType SubobjType) { |
| Result = APValue(Value); |
| return true; |
| } |
| bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) { |
| Result = APValue(extractStringLiteralCharacter( |
| Info, Subobj.getLValueBase().get<const Expr *>(), Character)); |
| return true; |
| } |
| }; |
| } // end anonymous namespace |
| |
| const AccessKinds ExtractSubobjectHandler::AccessKind; |
| |
| /// Extract the designated sub-object of an rvalue. |
| static bool extractSubobject(EvalInfo &Info, const Expr *E, |
| const CompleteObject &Obj, |
| const SubobjectDesignator &Sub, |
| APValue &Result) { |
| ExtractSubobjectHandler Handler = { Info, Result }; |
| return findSubobject(Info, E, Obj, Sub, Handler); |
| } |
| |
| namespace { |
| struct ModifySubobjectHandler { |
| EvalInfo &Info; |
| APValue &NewVal; |
| const Expr *E; |
| |
| typedef bool result_type; |
| static const AccessKinds AccessKind = AK_Assign; |
| |
| bool checkConst(QualType QT) { |
| // Assigning to a const object has undefined behavior. |
| if (QT.isConstQualified()) { |
| Info.Diag(E, diag::note_constexpr_modify_const_type) << QT; |
| return false; |
| } |
| return true; |
| } |
| |
| bool failed() { return false; } |
| bool found(APValue &Subobj, QualType SubobjType) { |
| if (!checkConst(SubobjType)) |
| return false; |
| // We've been given ownership of NewVal, so just swap it in. |
| Subobj.swap(NewVal); |
| return true; |
| } |
| bool found(APSInt &Value, QualType SubobjType) { |
| if (!checkConst(SubobjType)) |
| return false; |
| if (!NewVal.isInt()) { |
| // Maybe trying to write a cast pointer value into a complex? |
| Info.Diag(E); |
| return false; |
| } |
| Value = NewVal.getInt(); |
| return true; |
| } |
| bool found(APFloat &Value, QualType SubobjType) { |
| if (!checkConst(SubobjType)) |
| return false; |
| Value = NewVal.getFloat(); |
| return true; |
| } |
| bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) { |
| llvm_unreachable("shouldn't encounter string elements with ExpandArrays"); |
| } |
| }; |
| } // end anonymous namespace |
| |
| const AccessKinds ModifySubobjectHandler::AccessKind; |
| |
| /// Update the designated sub-object of an rvalue to the given value. |
| static bool modifySubobject(EvalInfo &Info, const Expr *E, |
| const CompleteObject &Obj, |
| const SubobjectDesignator &Sub, |
| APValue &NewVal) { |
| ModifySubobjectHandler Handler = { Info, NewVal, E }; |
| return findSubobject(Info, E, Obj, Sub, Handler); |
| } |
| |
| /// Find the position where two subobject designators diverge, or equivalently |
| /// the length of the common initial subsequence. |
| static unsigned FindDesignatorMismatch(QualType ObjType, |
| const SubobjectDesignator &A, |
| const SubobjectDesignator &B, |
| bool &WasArrayIndex) { |
| unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size()); |
| for (/**/; I != N; ++I) { |
| if (!ObjType.isNull() && |
| (ObjType->isArrayType() || ObjType->isAnyComplexType())) { |
| // Next subobject is an array element. |
| if (A.Entries[I].ArrayIndex != B.Entries[I].ArrayIndex) { |
| WasArrayIndex = true; |
| return I; |
| } |
| if (ObjType->isAnyComplexType()) |
| ObjType = ObjType->castAs<ComplexType>()->getElementType(); |
| else |
| ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType(); |
| } else { |
| if (A.Entries[I].BaseOrMember != B.Entries[I].BaseOrMember) { |
| WasArrayIndex = false; |
| return I; |
| } |
| if (const FieldDecl *FD = getAsField(A.Entries[I])) |
| // Next subobject is a field. |
| ObjType = FD->getType(); |
| else |
| // Next subobject is a base class. |
| ObjType = QualType(); |
| } |
| } |
| WasArrayIndex = false; |
| return I; |
| } |
| |
| /// Determine whether the given subobject designators refer to elements of the |
| /// same array object. |
| static bool AreElementsOfSameArray(QualType ObjType, |
| const SubobjectDesignator &A, |
| const SubobjectDesignator &B) { |
| if (A.Entries.size() != B.Entries.size()) |
| return false; |
| |
| bool IsArray = A.MostDerivedArraySize != 0; |
| if (IsArray && A.MostDerivedPathLength != A.Entries.size()) |
| // A is a subobject of the array element. |
| return false; |
| |
| // If A (and B) designates an array element, the last entry will be the array |
| // index. That doesn't have to match. Otherwise, we're in the 'implicit array |
| // of length 1' case, and the entire path must match. |
| bool WasArrayIndex; |
| unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex); |
| return CommonLength >= A.Entries.size() - IsArray; |
| } |
| |
| /// Find the complete object to which an LValue refers. |
| CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E, AccessKinds AK, |
| const LValue &LVal, QualType LValType) { |
| if (!LVal.Base) { |
| Info.Diag(E, diag::note_constexpr_access_null) << AK; |
| return CompleteObject(); |
| } |
| |
| CallStackFrame *Frame = 0; |
| if (LVal.CallIndex) { |
| Frame = Info.getCallFrame(LVal.CallIndex); |
| if (!Frame) { |
| Info.Diag(E, diag::note_constexpr_lifetime_ended, 1) |
| << AK << LVal.Base.is<const ValueDecl*>(); |
| NoteLValueLocation(Info, LVal.Base); |
| return CompleteObject(); |
| } |
| } |
| |
| // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type |
| // is not a constant expression (even if the object is non-volatile). We also |
| // apply this rule to C++98, in order to conform to the expected 'volatile' |
| // semantics. |
| if (LValType.isVolatileQualified()) { |
| if (Info.getLangOpts().CPlusPlus) |
| Info.Diag(E, diag::note_constexpr_access_volatile_type) |
| << AK << LValType; |
| else |
| Info.Diag(E); |
| return CompleteObject(); |
| } |
| |
| // Compute value storage location and type of base object. |
| APValue *BaseVal = 0; |
| QualType BaseType = getType(LVal.Base); |
| |
| if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl*>()) { |
| // In C++98, const, non-volatile integers initialized with ICEs are ICEs. |
| // In C++11, constexpr, non-volatile variables initialized with constant |
| // expressions are constant expressions too. Inside constexpr functions, |
| // parameters are constant expressions even if they're non-const. |
| // In C++1y, objects local to a constant expression (those with a Frame) are |
| // both readable and writable inside constant expressions. |
| // In C, such things can also be folded, although they are not ICEs. |
| const VarDecl *VD = dyn_cast<VarDecl>(D); |
| if (VD) { |
| if (const VarDecl *VDef = VD->getDefinition(Info.Ctx)) |
| VD = VDef; |
| } |
| if (!VD || VD->isInvalidDecl()) { |
| Info.Diag(E); |
| return CompleteObject(); |
| } |
| |
| // Accesses of volatile-qualified objects are not allowed. |
| if (BaseType.isVolatileQualified()) { |
| if (Info.getLangOpts().CPlusPlus) { |
| Info.Diag(E, diag::note_constexpr_access_volatile_obj, 1) |
| << AK << 1 << VD; |
| Info.Note(VD->getLocation(), diag::note_declared_at); |
| } else { |
| Info.Diag(E); |
| } |
| return CompleteObject(); |
| } |
| |
| // Unless we're looking at a local variable or argument in a constexpr call, |
| // the variable we're reading must be const. |
| if (!Frame) { |
| if (Info.getLangOpts().CPlusPlus1y && |
| VD == Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()) { |
| // OK, we can read and modify an object if we're in the process of |
| // evaluating its initializer, because its lifetime began in this |
| // evaluation. |
| } else if (AK != AK_Read) { |
| // All the remaining cases only permit reading. |
| Info.Diag(E, diag::note_constexpr_modify_global); |
| return CompleteObject(); |
| } else if (VD->isConstexpr()) { |
| // OK, we can read this variable. |
| } else if (BaseType->isIntegralOrEnumerationType()) { |
| if (!BaseType.isConstQualified()) { |
| if (Info.getLangOpts().CPlusPlus) { |
| Info.Diag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD; |
| Info.Note(VD->getLocation(), diag::note_declared_at); |
| } else { |
| Info.Diag(E); |
| } |
| return CompleteObject(); |
| } |
| } else if (BaseType->isFloatingType() && BaseType.isConstQualified()) { |
| // We support folding of const floating-point types, in order to make |
| // static const data members of such types (supported as an extension) |
| // more useful. |
| if (Info.getLangOpts().CPlusPlus11) { |
| Info.CCEDiag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD; |
| Info.Note(VD->getLocation(), diag::note_declared_at); |
| } else { |
| Info.CCEDiag(E); |
| } |
| } else { |
| // FIXME: Allow folding of values of any literal type in all languages. |
| if (Info.getLangOpts().CPlusPlus11) { |
| Info.Diag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD; |
| Info.Note(VD->getLocation(), diag::note_declared_at); |
| } else { |
| Info.Diag(E); |
| } |
| return CompleteObject(); |
| } |
| } |
| |
| if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal)) |
| return CompleteObject(); |
| } else { |
| const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); |
| |
| if (!Frame) { |
| if (const MaterializeTemporaryExpr *MTE = |
| dyn_cast<MaterializeTemporaryExpr>(Base)) { |
| assert(MTE->getStorageDuration() == SD_Static && |
| "should have a frame for a non-global materialized temporary"); |
| |
| // Per C++1y [expr.const]p2: |
| // an lvalue-to-rvalue conversion [is not allowed unless it applies to] |
| // - a [...] glvalue of integral or enumeration type that refers to |
| // a non-volatile const object [...] |
| // [...] |
| // - a [...] glvalue of literal type that refers to a non-volatile |
| // object whose lifetime began within the evaluation of e. |
| // |
| // C++11 misses the 'began within the evaluation of e' check and |
| // instead allows all temporaries, including things like: |
| // int &&r = 1; |
| // int x = ++r; |
| // constexpr int k = r; |
| // Therefore we use the C++1y rules in C++11 too. |
| const ValueDecl *VD = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>(); |
| const ValueDecl *ED = MTE->getExtendingDecl(); |
| if (!(BaseType.isConstQualified() && |
| BaseType->isIntegralOrEnumerationType()) && |
| !(VD && VD->getCanonicalDecl() == ED->getCanonicalDecl())) { |
| Info.Diag(E, diag::note_constexpr_access_static_temporary, 1) << AK; |
| Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here); |
| return CompleteObject(); |
| } |
| |
| BaseVal = Info.Ctx.getMaterializedTemporaryValue(MTE, false); |
| assert(BaseVal && "got reference to unevaluated temporary"); |
| } else { |
| Info.Diag(E); |
| return CompleteObject(); |
| } |
| } else { |
| BaseVal = Frame->getTemporary(Base); |
| assert(BaseVal && "missing value for temporary"); |
| } |
| |
| // Volatile temporary objects cannot be accessed in constant expressions. |
| if (BaseType.isVolatileQualified()) { |
| if (Info.getLangOpts().CPlusPlus) { |
| Info.Diag(E, diag::note_constexpr_access_volatile_obj, 1) |
| << AK << 0; |
| Info.Note(Base->getExprLoc(), diag::note_constexpr_temporary_here); |
| } else { |
| Info.Diag(E); |
| } |
| return CompleteObject(); |
| } |
| } |
| |
| // During the construction of an object, it is not yet 'const'. |
| // FIXME: We don't set up EvaluatingDecl for local variables or temporaries, |
| // and this doesn't do quite the right thing for const subobjects of the |
| // object under construction. |
| if (LVal.getLValueBase() == Info.EvaluatingDecl) { |
| BaseType = Info.Ctx.getCanonicalType(BaseType); |
| BaseType.removeLocalConst(); |
| } |
| |
| // In C++1y, we can't safely access any mutable state when we might be |
| // evaluating after an unmodeled side effect or an evaluation failure. |
| // |
| // FIXME: Not all local state is mutable. Allow local constant subobjects |
| // to be read here (but take care with 'mutable' fields). |
| if (Frame && Info.getLangOpts().CPlusPlus1y && |
| (Info.EvalStatus.HasSideEffects || Info.keepEvaluatingAfterFailure())) |
| return CompleteObject(); |
| |
| return CompleteObject(BaseVal, BaseType); |
| } |
| |
| /// \brief Perform an lvalue-to-rvalue conversion on the given glvalue. This |
| /// can also be used for 'lvalue-to-lvalue' conversions for looking up the |
| /// glvalue referred to by an entity of reference type. |
| /// |
| /// \param Info - Information about the ongoing evaluation. |
| /// \param Conv - The expression for which we are performing the conversion. |
| /// Used for diagnostics. |
| /// \param Type - The type of the glvalue (before stripping cv-qualifiers in the |
| /// case of a non-class type). |
| /// \param LVal - The glvalue on which we are attempting to perform this action. |
| /// \param RVal - The produced value will be placed here. |
| static bool handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, |
| QualType Type, |
| const LValue &LVal, APValue &RVal) { |
| if (LVal.Designator.Invalid) |
| return false; |
| |
| // Check for special cases where there is no existing APValue to look at. |
| const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); |
| if (!LVal.Designator.Invalid && Base && !LVal.CallIndex && |
| !Type.isVolatileQualified()) { |
| if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) { |
| // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the |
| // initializer until now for such expressions. Such an expression can't be |
| // an ICE in C, so this only matters for fold. |
| assert(!Info.getLangOpts().CPlusPlus && "lvalue compound literal in c++?"); |
| if (Type.isVolatileQualified()) { |
| Info.Diag(Conv); |
| return false; |
| } |
| APValue Lit; |
| if (!Evaluate(Lit, Info, CLE->getInitializer())) |
| return false; |
| CompleteObject LitObj(&Lit, Base->getType()); |
| return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal); |
| } else if (isa<StringLiteral>(Base)) { |
| // We represent a string literal array as an lvalue pointing at the |
| // corresponding expression, rather than building an array of chars. |
| // FIXME: Support PredefinedExpr, ObjCEncodeExpr, MakeStringConstant |
| APValue Str(Base, CharUnits::Zero(), APValue::NoLValuePath(), 0); |
| CompleteObject StrObj(&Str, Base->getType()); |
| return extractSubobject(Info, Conv, StrObj, LVal.Designator, RVal); |
| } |
| } |
| |
| CompleteObject Obj = findCompleteObject(Info, Conv, AK_Read, LVal, Type); |
| return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal); |
| } |
| |
| /// Perform an assignment of Val to LVal. Takes ownership of Val. |
| static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal, |
| QualType LValType, APValue &Val) { |
| if (LVal.Designator.Invalid) |
| return false; |
| |
| if (!Info.getLangOpts().CPlusPlus1y) { |
| Info.Diag(E); |
| return false; |
| } |
| |
| CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType); |
| return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val); |
| } |
| |
| static bool isOverflowingIntegerType(ASTContext &Ctx, QualType T) { |
| return T->isSignedIntegerType() && |
| Ctx.getIntWidth(T) >= Ctx.getIntWidth(Ctx.IntTy); |
| } |
| |
| namespace { |
| struct CompoundAssignSubobjectHandler { |
| EvalInfo &Info; |
| const Expr *E; |
| QualType PromotedLHSType; |
| BinaryOperatorKind Opcode; |
| const APValue &RHS; |
| |
| static const AccessKinds AccessKind = AK_Assign; |
| |
| typedef bool result_type; |
| |
| bool checkConst(QualType QT) { |
| // Assigning to a const object has undefined behavior. |
| if (QT.isConstQualified()) { |
| Info.Diag(E, diag::note_constexpr_modify_const_type) << QT; |
| return false; |
| } |
| return true; |
| } |
| |
| bool failed() { return false; } |
| bool found(APValue &Subobj, QualType SubobjType) { |
| switch (Subobj.getKind()) { |
| case APValue::Int: |
| return found(Subobj.getInt(), SubobjType); |
| case APValue::Float: |
| return found(Subobj.getFloat(), SubobjType); |
| case APValue::ComplexInt: |
| case APValue::ComplexFloat: |
| // FIXME: Implement complex compound assignment. |
| Info.Diag(E); |
| return false; |
| case APValue::LValue: |
| return foundPointer(Subobj, SubobjType); |
| default: |
| // FIXME: can this happen? |
| Info.Diag(E); |
| return false; |
| } |
| } |
| bool found(APSInt &Value, QualType SubobjType) { |
| if (!checkConst(SubobjType)) |
| return false; |
| |
| if (!SubobjType->isIntegerType() || !RHS.isInt()) { |
| // We don't support compound assignment on integer-cast-to-pointer |
| // values. |
| Info.Diag(E); |
| return false; |
| } |
| |
| APSInt LHS = HandleIntToIntCast(Info, E, PromotedLHSType, |
| SubobjType, Value); |
| if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS)) |
| return false; |
| Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS); |
| return true; |
| } |
| bool found(APFloat &Value, QualType SubobjType) { |
| return checkConst(SubobjType) && |
| HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType, |
| Value) && |
| handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) && |
| HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value); |
| } |
| bool foundPointer(APValue &Subobj, QualType SubobjType) { |
| if (!checkConst(SubobjType)) |
| return false; |
| |
| QualType PointeeType; |
| if (const PointerType *PT = SubobjType->getAs<PointerType>()) |
| PointeeType = PT->getPointeeType(); |
| |
| if (PointeeType.isNull() || !RHS.isInt() || |
| (Opcode != BO_Add && Opcode != BO_Sub)) { |
| Info.Diag(E); |
| return false; |
| } |
| |
| int64_t Offset = getExtValue(RHS.getInt()); |
| if (Opcode == BO_Sub) |
| Offset = -Offset; |
| |
| LValue LVal; |
| LVal.setFrom(Info.Ctx, Subobj); |
| if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset)) |
| return false; |
| LVal.moveInto(Subobj); |
| return true; |
| } |
| bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) { |
| llvm_unreachable("shouldn't encounter string elements here"); |
| } |
| }; |
| } // end anonymous namespace |
| |
| const AccessKinds CompoundAssignSubobjectHandler::AccessKind; |
| |
| /// Perform a compound assignment of LVal <op>= RVal. |
| static bool handleCompoundAssignment( |
| EvalInfo &Info, const Expr *E, |
| const LValue &LVal, QualType LValType, QualType PromotedLValType, |
| BinaryOperatorKind Opcode, const APValue &RVal) { |
| if (LVal.Designator.Invalid) |
| return false; |
| |
| if (!Info.getLangOpts().CPlusPlus1y) { |
| Info.Diag(E); |
| return false; |
| } |
| |
| CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType); |
| CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode, |
| RVal }; |
| return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler); |
| } |
| |
| namespace { |
| struct IncDecSubobjectHandler { |
| EvalInfo &Info; |
| const Expr *E; |
| AccessKinds AccessKind; |
| APValue *Old; |
| |
| typedef bool result_type; |
| |
| bool checkConst(QualType QT) { |
| // Assigning to a const object has undefined behavior. |
| if (QT.isConstQualified()) { |
| Info.Diag(E, diag::note_constexpr_modify_const_type) << QT; |
| return false; |
| } |
| return true; |
| } |
| |
| bool failed() { return false; } |
| bool found(APValue &Subobj, QualType SubobjType) { |
| // Stash the old value. Also clear Old, so we don't clobber it later |
| // if we're post-incrementing a complex. |
| if (Old) { |
| *Old = Subobj; |
| Old = 0; |
| } |
| |
| switch (Subobj.getKind()) { |
| case APValue::Int: |
| return found(Subobj.getInt(), SubobjType); |
| case APValue::Float: |
| return found(Subobj.getFloat(), SubobjType); |
| case APValue::ComplexInt: |
| return found(Subobj.getComplexIntReal(), |
| SubobjType->castAs<ComplexType>()->getElementType() |
| .withCVRQualifiers(SubobjType.getCVRQualifiers())); |
| case APValue::ComplexFloat: |
| return found(Subobj.getComplexFloatReal(), |
| SubobjType->castAs<ComplexType>()->getElementType() |
| .withCVRQualifiers(SubobjType.getCVRQualifiers())); |
| case APValue::LValue: |
| return foundPointer(Subobj, SubobjType); |
| default: |
| // FIXME: can this happen? |
| Info.Diag(E); |
| return false; |
| } |
| } |
| bool found(APSInt &Value, QualType SubobjType) { |
| if (!checkConst(SubobjType)) |
| return false; |
| |
| if (!SubobjType->isIntegerType()) { |
| // We don't support increment / decrement on integer-cast-to-pointer |
| // values. |
| Info.Diag(E); |
| return false; |
| } |
| |
| if (Old) *Old = APValue(Value); |
| |
| // bool arithmetic promotes to int, and the conversion back to bool |
| // doesn't reduce mod 2^n, so special-case it. |
| if (SubobjType->isBooleanType()) { |
| if (AccessKind == AK_Increment) |
| Value = 1; |
| else |
| Value = !Value; |
| return true; |
| } |
| |
| bool WasNegative = Value.isNegative(); |
| if (AccessKind == AK_Increment) { |
| ++Value; |
| |
| if (!WasNegative && Value.isNegative() && |
| isOverflowingIntegerType(Info.Ctx, SubobjType)) { |
| APSInt ActualValue(Value, /*IsUnsigned*/true); |
| HandleOverflow(Info, E, ActualValue, SubobjType); |
| } |
| } else { |
| --Value; |
| |
| if (WasNegative && !Value.isNegative() && |
| isOverflowingIntegerType(Info.Ctx, SubobjType)) { |
| unsigned BitWidth = Value.getBitWidth(); |
| APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false); |
| ActualValue.setBit(BitWidth); |
| HandleOverflow(Info, E, ActualValue, SubobjType); |
| } |
| } |
| return true; |
| } |
| bool found(APFloat &Value, QualType SubobjType) { |
| if (!checkConst(SubobjType)) |
| return false; |
| |
| if (Old) *Old = APValue(Value); |
| |
| APFloat One(Value.getSemantics(), 1); |
| if (AccessKind == AK_Increment) |
| Value.add(One, APFloat::rmNearestTiesToEven); |
| else |
| Value.subtract(One, APFloat::rmNearestTiesToEven); |
| return true; |
| } |
| bool foundPointer(APValue &Subobj, QualType SubobjType) { |
| if (!checkConst(SubobjType)) |
| return false; |
| |
| QualType PointeeType; |
| if (const PointerType *PT = SubobjType->getAs<PointerType>()) |
| PointeeType = PT->getPointeeType(); |
| else { |
| Info.Diag(E); |
| return false; |
| } |
| |
| LValue LVal; |
| LVal.setFrom(Info.Ctx, Subobj); |
| if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, |
| AccessKind == AK_Increment ? 1 : -1)) |
| return false; |
| LVal.moveInto(Subobj); |
| return true; |
| } |
| bool foundString(APValue &Subobj, QualType SubobjType, uint64_t Character) { |
| llvm_unreachable("shouldn't encounter string elements here"); |
| } |
| }; |
| } // end anonymous namespace |
| |
| /// Perform an increment or decrement on LVal. |
| static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal, |
| QualType LValType, bool IsIncrement, APValue *Old) { |
| if (LVal.Designator.Invalid) |
| return false; |
| |
| if (!Info.getLangOpts().CPlusPlus1y) { |
| Info.Diag(E); |
| return false; |
| } |
| |
| AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement; |
| CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType); |
| IncDecSubobjectHandler Handler = { Info, E, AK, Old }; |
| return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler); |
| } |
| |
| /// Build an lvalue for the object argument of a member function call. |
| static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object, |
| LValue &This) { |
| if (Object->getType()->isPointerType()) |
| return EvaluatePointer(Object, This, Info); |
| |
| if (Object->isGLValue()) |
| return EvaluateLValue(Object, This, Info); |
| |
| if (Object->getType()->isLiteralType(Info.Ctx)) |
| return EvaluateTemporary(Object, This, Info); |
| |
| return false; |
| } |
| |
| /// HandleMemberPointerAccess - Evaluate a member access operation and build an |
| /// lvalue referring to the result. |
| /// |
| /// \param Info - Information about the ongoing evaluation. |
| /// \param LV - An lvalue referring to the base of the member pointer. |
| /// \param RHS - The member pointer expression. |
| /// \param IncludeMember - Specifies whether the member itself is included in |
| /// the resulting LValue subobject designator. This is not possible when |
| /// creating a bound member function. |
| /// \return The field or method declaration to which the member pointer refers, |
| /// or 0 if evaluation fails. |
| static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, |
| QualType LVType, |
| LValue &LV, |
| const Expr *RHS, |
| bool IncludeMember = true) { |
| MemberPtr MemPtr; |
| if (!EvaluateMemberPointer(RHS, MemPtr, Info)) |
| return 0; |
| |
| // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to |
| // member value, the behavior is undefined. |
| if (!MemPtr.getDecl()) { |
| // FIXME: Specific diagnostic. |
| Info.Diag(RHS); |
| return 0; |
| } |
| |
| if (MemPtr.isDerivedMember()) { |
| // This is a member of some derived class. Truncate LV appropriately. |
| // The end of the derived-to-base path for the base object must match the |
| // derived-to-base path for the member pointer. |
| if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() > |
| LV.Designator.Entries.size()) { |
| Info.Diag(RHS); |
| return 0; |
| } |
| unsigned PathLengthToMember = |
| LV.Designator.Entries.size() - MemPtr.Path.size(); |
| for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) { |
| const CXXRecordDecl *LVDecl = getAsBaseClass( |
| LV.Designator.Entries[PathLengthToMember + I]); |
| const CXXRecordDecl *MPDecl = MemPtr.Path[I]; |
| if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) { |
| Info.Diag(RHS); |
| return 0; |
| } |
| } |
| |
| // Truncate the lvalue to the appropriate derived class. |
| if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(), |
| PathLengthToMember)) |
| return 0; |
| } else if (!MemPtr.Path.empty()) { |
| // Extend the LValue path with the member pointer's path. |
| LV.Designator.Entries.reserve(LV.Designator.Entries.size() + |
| MemPtr.Path.size() + IncludeMember); |
| |
| // Walk down to the appropriate base class. |
| if (const PointerType *PT = LVType->getAs<PointerType>()) |
| LVType = PT->getPointeeType(); |
| const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl(); |
| assert(RD && "member pointer access on non-class-type expression"); |
| // The first class in the path is that of the lvalue. |
| for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) { |
| const CXXRecordDecl *Base = MemPtr.Path[N - I - 1]; |
| if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base)) |
| return 0; |
| RD = Base; |
| } |
| // Finally cast to the class containing the member. |
| if (!HandleLValueDirectBase(Info, RHS, LV, RD, |
| MemPtr.getContainingRecord())) |
| return 0; |
| } |
| |
| // Add the member. Note that we cannot build bound member functions here. |
| if (IncludeMember) { |
| if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) { |
| if (!HandleLValueMember(Info, RHS, LV, FD)) |
| return 0; |
| } else if (const IndirectFieldDecl *IFD = |
| dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) { |
| if (!HandleLValueIndirectMember(Info, RHS, LV, IFD)) |
| return 0; |
| } else { |
| llvm_unreachable("can't construct reference to bound member function"); |
| } |
| } |
| |
| return MemPtr.getDecl(); |
| } |
| |
| static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, |
| const BinaryOperator *BO, |
| LValue &LV, |
| bool IncludeMember = true) { |
| assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI); |
| |
| if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) { |
| if (Info.keepEvaluatingAfterFailure()) { |
| MemberPtr MemPtr; |
| EvaluateMemberPointer(BO->getRHS(), MemPtr, Info); |
| } |
| return 0; |
| } |
| |
| return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV, |
| BO->getRHS(), IncludeMember); |
| } |
| |
| /// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on |
| /// the provided lvalue, which currently refers to the base object. |
| static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E, |
| LValue &Result) { |
| SubobjectDesignator &D = Result.Designator; |
| if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived)) |
| return false; |
| |
| QualType TargetQT = E->getType(); |
| if (const PointerType *PT = TargetQT->getAs<PointerType>()) |
| TargetQT = PT->getPointeeType(); |
| |
| // Check this cast lands within the final derived-to-base subobject path. |
| if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) { |
| Info.CCEDiag(E, diag::note_constexpr_invalid_downcast) |
| << D.MostDerivedType << TargetQT; |
| return false; |
| } |
| |
| // Check the type of the final cast. We don't need to check the path, |
| // since a cast can only be formed if the path is unique. |
| unsigned NewEntriesSize = D.Entries.size() - E->path_size(); |
| const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl(); |
| const CXXRecordDecl *FinalType; |
| if (NewEntriesSize == D.MostDerivedPathLength) |
| FinalType = D.MostDerivedType->getAsCXXRecordDecl(); |
| else |
| FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]); |
| if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) { |
| Info.CCEDiag(E, diag::note_constexpr_invalid_downcast) |
| << D.MostDerivedType << TargetQT; |
| return false; |
| } |
| |
| // Truncate the lvalue to the appropriate derived class. |
| return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize); |
| } |
| |
| namespace { |
| enum EvalStmtResult { |
| /// Evaluation failed. |
| ESR_Failed, |
| /// Hit a 'return' statement. |
| ESR_Returned, |
| /// Evaluation succeeded. |
| ESR_Succeeded, |
| /// Hit a 'continue' statement. |
| ESR_Continue, |
| /// Hit a 'break' statement. |
| ESR_Break, |
| /// Still scanning for 'case' or 'default' statement. |
| ESR_CaseNotFound |
| }; |
| } |
| |
| static bool EvaluateDecl(EvalInfo &Info, const Decl *D) { |
| if (const VarDecl *VD = dyn_cast<VarDecl>(D)) { |
| // We don't need to evaluate the initializer for a static local. |
| if (!VD->hasLocalStorage()) |
| return true; |
| |
| LValue Result; |
| Result.set(VD, Info.CurrentCall->Index); |
| APValue &Val = Info.CurrentCall->createTemporary(VD, true); |
| |
| if (!VD->getInit()) { |
| Info.Diag(D->getLocStart(), diag::note_constexpr_uninitialized) |
| << false << VD->getType(); |
| Val = APValue(); |
| return false; |
| } |
| |
| if (!EvaluateInPlace(Val, Info, Result, VD->getInit())) { |
| // Wipe out any partially-computed value, to allow tracking that this |
| // evaluation failed. |
| Val = APValue(); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| /// Evaluate a condition (either a variable declaration or an expression). |
| static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl, |
| const Expr *Cond, bool &Result) { |
| FullExpressionRAII Scope(Info); |
| if (CondDecl && !EvaluateDecl(Info, CondDecl)) |
| return false; |
| return EvaluateAsBooleanCondition(Cond, Result, Info); |
| } |
| |
| static EvalStmtResult EvaluateStmt(APValue &Result, EvalInfo &Info, |
| const Stmt *S, const SwitchCase *SC = 0); |
| |
| /// Evaluate the body of a loop, and translate the result as appropriate. |
| static EvalStmtResult EvaluateLoopBody(APValue &Result, EvalInfo &Info, |
| const Stmt *Body, |
| const SwitchCase *Case = 0) { |
| BlockScopeRAII Scope(Info); |
| switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case)) { |
| case ESR_Break: |
| return ESR_Succeeded; |
| case ESR_Succeeded: |
| case ESR_Continue: |
| return ESR_Continue; |
| case ESR_Failed: |
| case ESR_Returned: |
| case ESR_CaseNotFound: |
| return ESR; |
| } |
| llvm_unreachable("Invalid EvalStmtResult!"); |
| } |
| |
| /// Evaluate a switch statement. |
| static EvalStmtResult EvaluateSwitch(APValue &Result, EvalInfo &Info, |
| const SwitchStmt *SS) { |
| BlockScopeRAII Scope(Info); |
| |
| // Evaluate the switch condition. |
| APSInt Value; |
| { |
| FullExpressionRAII Scope(Info); |
| if (SS->getConditionVariable() && |
| !EvaluateDecl(Info, SS->getConditionVariable())) |
| return ESR_Failed; |
| if (!EvaluateInteger(SS->getCond(), Value, Info)) |
| return ESR_Failed; |
| } |
| |
| // Find the switch case corresponding to the value of the condition. |
| // FIXME: Cache this lookup. |
| const SwitchCase *Found = 0; |
| for (const SwitchCase *SC = SS->getSwitchCaseList(); SC; |
| SC = SC->getNextSwitchCase()) { |
| if (isa<DefaultStmt>(SC)) { |
| Found = SC; |
| continue; |
| } |
| |
| const CaseStmt *CS = cast<CaseStmt>(SC); |
| APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx); |
| APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx) |
| : LHS; |
| if (LHS <= Value && Value <= RHS) { |
| Found = SC; |
| break; |
| } |
| } |
| |
| if (!Found) |
| return ESR_Succeeded; |
| |
| // Search the switch body for the switch case and evaluate it from there. |
| switch (EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found)) { |
| case ESR_Break: |
| return ESR_Succeeded; |
| case ESR_Succeeded: |
| case ESR_Continue: |
| case ESR_Failed: |
| case ESR_Returned: |
| return ESR; |
| case ESR_CaseNotFound: |
| // This can only happen if the switch case is nested within a statement |
| // expression. We have no intention of supporting that. |
| Info.Diag(Found->getLocStart(), diag::note_constexpr_stmt_expr_unsupported); |
| return ESR_Failed; |
| } |
| llvm_unreachable("Invalid EvalStmtResult!"); |
| } |
| |
| // Evaluate a statement. |
| static EvalStmtResult EvaluateStmt(APValue &Result, EvalInfo &Info, |
| const Stmt *S, const SwitchCase *Case) { |
| if (!Info.nextStep(S)) |
| return ESR_Failed; |
| |
| // If we're hunting down a 'case' or 'default' label, recurse through |
| // substatements until we hit the label. |
| if (Case) { |
| // FIXME: We don't start the lifetime of objects whose initialization we |
| // jump over. However, such objects must be of class type with a trivial |
| // default constructor that initialize all subobjects, so must be empty, |
| // so this almost never matters. |
| switch (S->getStmtClass()) { |
| case Stmt::CompoundStmtClass: |
| // FIXME: Precompute which substatement of a compound statement we |
| // would jump to, and go straight there rather than performing a |
| // linear scan each time. |
| case Stmt::LabelStmtClass: |
| case Stmt::AttributedStmtClass: |
| case Stmt::DoStmtClass: |
| break; |
| |
| case Stmt::CaseStmtClass: |
| case Stmt::DefaultStmtClass: |
| if (Case == S) |
| Case = 0; |
| break; |
| |
| case Stmt::IfStmtClass: { |
| // FIXME: Precompute which side of an 'if' we would jump to, and go |
| // straight there rather than scanning both sides. |
| const IfStmt *IS = cast<IfStmt>(S); |
| |
| // Wrap the evaluation in a block scope, in case it's a DeclStmt |
| // preceded by our switch label. |
| BlockScopeRAII Scope(Info); |
| |
| EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case); |
| if (ESR != ESR_CaseNotFound || !IS->getElse()) |
| return ESR; |
| return EvaluateStmt(Result, Info, IS->getElse(), Case); |
| } |
| |
| case Stmt::WhileStmtClass: { |
| EvalStmtResult ESR = |
| EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case); |
| if (ESR != ESR_Continue) |
| return ESR; |
| break; |
| } |
| |
| case Stmt::ForStmtClass: { |
| const ForStmt *FS = cast<ForStmt>(S); |
| EvalStmtResult ESR = |
| EvaluateLoopBody(Result, Info, FS->getBody(), Case); |
| if (ESR != ESR_Continue) |
| return ESR; |
| if (FS->getInc()) { |
| FullExpressionRAII IncScope(Info); |
| if (!EvaluateIgnoredValue(Info, FS->getInc())) |
| return ESR_Failed; |
| } |
| break; |
| } |
| |
| case Stmt::DeclStmtClass: |
| // FIXME: If the variable has initialization that can't be jumped over, |
| // bail out of any immediately-surrounding compound-statement too. |
| default: |
| return ESR_CaseNotFound; |
| } |
| } |
| |
| switch (S->getStmtClass()) { |
| default: |
| if (const Expr *E = dyn_cast<Expr>(S)) { |
| // Don't bother evaluating beyond an expression-statement which couldn't |
| // be evaluated. |
| FullExpressionRAII Scope(Info); |
| if (!EvaluateIgnoredValue(Info, E)) |
| return ESR_Failed; |
| return ESR_Succeeded; |
| } |
| |
| Info.Diag(S->getLocStart()); |
| return ESR_Failed; |
| |
| case Stmt::NullStmtClass: |
| return ESR_Succeeded; |
| |
| case Stmt::DeclStmtClass: { |
| const DeclStmt *DS = cast<DeclStmt>(S); |
| for (DeclStmt::const_decl_iterator DclIt = DS->decl_begin(), |
| DclEnd = DS->decl_end(); DclIt != DclEnd; ++DclIt) { |
| // Each declaration initialization is its own full-expression. |
| // FIXME: This isn't quite right; if we're performing aggregate |
| // initialization, each braced subexpression is its own full-expression. |
| FullExpressionRAII Scope(Info); |
| if (!EvaluateDecl(Info, *DclIt) && !Info.keepEvaluatingAfterFailure()) |
| return ESR_Failed; |
| } |
| return ESR_Succeeded; |
| } |
| |
| case Stmt::ReturnStmtClass: { |
| const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue(); |
| FullExpressionRAII Scope(Info); |
| if (RetExpr && !Evaluate(Result, Info, RetExpr)) |
| return ESR_Failed; |
| return ESR_Returned; |
| } |
| |
| case Stmt::CompoundStmtClass: { |
| BlockScopeRAII Scope(Info); |
| |
| const CompoundStmt *CS = cast<CompoundStmt>(S); |
| for (CompoundStmt::const_body_iterator BI = CS->body_begin(), |
| BE = CS->body_end(); BI != BE; ++BI) { |
| EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI, Case); |
| if (ESR == ESR_Succeeded) |
| Case = 0; |
| else if (ESR != ESR_CaseNotFound) |
| return ESR; |
| } |
| return Case ? ESR_CaseNotFound : ESR_Succeeded; |
| } |
| |
| case Stmt::IfStmtClass: { |
| const IfStmt *IS = cast<IfStmt>(S); |
| |
| // Evaluate the condition, as either a var decl or as an expression. |
| BlockScopeRAII Scope(Info); |
| bool Cond; |
| if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond)) |
| return ESR_Failed; |
| |
| if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) { |
| EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt); |
| if (ESR != ESR_Succeeded) |
| return ESR; |
| } |
| return ESR_Succeeded; |
| } |
| |
| case Stmt::WhileStmtClass: { |
| const WhileStmt *WS = cast<WhileStmt>(S); |
| while (true) { |
| BlockScopeRAII Scope(Info); |
| bool Continue; |
| if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(), |
| Continue)) |
| return ESR_Failed; |
| if (!Continue) |
| break; |
| |
| EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody()); |
| if (ESR != ESR_Continue) |
| return ESR; |
| } |
| return ESR_Succeeded; |
| } |
| |
| case Stmt::DoStmtClass: { |
| const DoStmt *DS = cast<DoStmt>(S); |
| bool Continue; |
| do { |
| EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case); |
| if (ESR != ESR_Continue) |
| return ESR; |
| Case = 0; |
| |
| FullExpressionRAII CondScope(Info); |
| if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info)) |
| return ESR_Failed; |
| } while (Continue); |
| return ESR_Succeeded; |
| } |
| |
| case Stmt::ForStmtClass: { |
| const ForStmt *FS = cast<ForStmt>(S); |
| BlockScopeRAII Scope(Info); |
| if (FS->getInit()) { |
| EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit()); |
| if (ESR != ESR_Succeeded) |
| return ESR; |
| } |
| while (true) { |
| BlockScopeRAII Scope(Info); |
| bool Continue = true; |
| if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(), |
| FS->getCond(), Continue)) |
| return ESR_Failed; |
| if (!Continue) |
| break; |
| |
| EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody()); |
| if (ESR != ESR_Continue) |
| return ESR; |
| |
| if (FS->getInc()) { |
| FullExpressionRAII IncScope(Info); |
| if (!EvaluateIgnoredValue(Info, FS->getInc())) |
| return ESR_Failed; |
| } |
| } |
| return ESR_Succeeded; |
| } |
| |
| case Stmt::CXXForRangeStmtClass: { |
| const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S); |
| BlockScopeRAII Scope(Info); |
| |
| // Initialize the __range variable. |
| EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt()); |
| if (ESR != ESR_Succeeded) |
| return ESR; |
| |
| // Create the __begin and __end iterators. |
| ESR = EvaluateStmt(Result, Info, FS->getBeginEndStmt()); |
| if (ESR != ESR_Succeeded) |
| return ESR; |
| |
| while (true) { |
| // Condition: __begin != __end. |
| { |
| bool Continue = true; |
| FullExpressionRAII CondExpr(Info); |
| if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info)) |
| return ESR_Failed; |
| if (!Continue) |
| break; |
| } |
| |
| // User's variable declaration, initialized by *__begin. |
| BlockScopeRAII InnerScope(Info); |
| ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt()); |
| if (ESR != ESR_Succeeded) |
| return ESR; |
| |
| // Loop body. |
| ESR = EvaluateLoopBody(Result, Info, FS->getBody()); |
| if (ESR != ESR_Continue) |
| return ESR; |
| |
| // Increment: ++__begin |
| if (!EvaluateIgnoredValue(Info, FS->getInc())) |
| return ESR_Failed; |
| } |
| |
| return ESR_Succeeded; |
| } |
| |
| case Stmt::SwitchStmtClass: |
| return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S)); |
| |
| case Stmt::ContinueStmtClass: |
| return ESR_Continue; |
| |
| case Stmt::BreakStmtClass: |
| return ESR_Break; |
| |
| case Stmt::LabelStmtClass: |
| return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case); |
| |
| case Stmt::AttributedStmtClass: |
| // As a general principle, C++11 attributes can be ignored without |
| // any semantic impact. |
| return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(), |
| Case); |
| |
| case Stmt::CaseStmtClass: |
| case Stmt::DefaultStmtClass: |
| return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case); |
| } |
| } |
| |
| /// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial |
| /// default constructor. If so, we'll fold it whether or not it's marked as |
| /// constexpr. If it is marked as constexpr, we will never implicitly define it, |
| /// so we need special handling. |
| static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc, |
| const CXXConstructorDecl *CD, |
| bool IsValueInitialization) { |
| if (!CD->isTrivial() || !CD->isDefaultConstructor()) |
| return false; |
| |
| // Value-initialization does not call a trivial default constructor, so such a |
| // call is a core constant expression whether or not the constructor is |
| // constexpr. |
| if (!CD->isConstexpr() && !IsValueInitialization) { |
| if (Info.getLangOpts().CPlusPlus11) { |
| // FIXME: If DiagDecl is an implicitly-declared special member function, |
| // we should be much more explicit about why it's not constexpr. |
| Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1) |
| << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD; |
| Info.Note(CD->getLocation(), diag::note_declared_at); |
| } else { |
| Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr); |
| } |
| } |
| return true; |
| } |
| |
| /// CheckConstexprFunction - Check that a function can be called in a constant |
| /// expression. |
| static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc, |
| const FunctionDecl *Declaration, |
| const FunctionDecl *Definition) { |
| // Potential constant expressions can contain calls to declared, but not yet |
| // defined, constexpr functions. |
| if (Info.checkingPotentialConstantExpression() && !Definition && |
| Declaration->isConstexpr()) |
| return false; |
| |
| // Bail out with no diagnostic if the function declaration itself is invalid. |
| // We will have produced a relevant diagnostic while parsing it. |
| if (Declaration->isInvalidDecl()) |
| return false; |
| |
| // Can we evaluate this function call? |
| if (Definition && Definition->isConstexpr() && !Definition->isInvalidDecl()) |
| return true; |
| |
| if (Info.getLangOpts().CPlusPlus11) { |
| const FunctionDecl *DiagDecl = Definition ? Definition : Declaration; |
| // FIXME: If DiagDecl is an implicitly-declared special member function, we |
| // should be much more explicit about why it's not constexpr. |
| Info.Diag(CallLoc, diag::note_constexpr_invalid_function, 1) |
| << DiagDecl->isConstexpr() << isa<CXXConstructorDecl>(DiagDecl) |
| << DiagDecl; |
| Info.Note(DiagDecl->getLocation(), diag::note_declared_at); |
| } else { |
| Info.Diag(CallLoc, diag::note_invalid_subexpr_in_const_expr); |
| } |
| return false; |
| } |
| |
| namespace { |
| typedef SmallVector<APValue, 8> ArgVector; |
| } |
| |
| /// EvaluateArgs - Evaluate the arguments to a function call. |
| static bool EvaluateArgs(ArrayRef<const Expr*> Args, ArgVector &ArgValues, |
| EvalInfo &Info) { |
| bool Success = true; |
| for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end(); |
| I != E; ++I) { |
| if (!Evaluate(ArgValues[I - Args.begin()], Info, *I)) { |
| // If we're checking for a potential constant expression, evaluate all |
| // initializers even if some of them fail. |
| if (!Info.keepEvaluatingAfterFailure()) |
| return false; |
| Success = false; |
| } |
| } |
| return Success; |
| } |
| |
| /// Evaluate a function call. |
| static bool HandleFunctionCall(SourceLocation CallLoc, |
| const FunctionDecl *Callee, const LValue *This, |
| ArrayRef<const Expr*> Args, const Stmt *Body, |
| EvalInfo &Info, APValue &Result) { |
| ArgVector ArgValues(Args.size()); |
| if (!EvaluateArgs(Args, ArgValues, Info)) |
| return false; |
| |
| if (!Info.CheckCallLimit(CallLoc)) |
| return false; |
| |
| CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data()); |
| |
| // For a trivial copy or move assignment, perform an APValue copy. This is |
| // essential for unions, where the operations performed by the assignment |
| // operator cannot be represented as statements. |
| const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee); |
| if (MD && MD->isDefaulted() && MD->isTrivial()) { |
| assert(This && |
| (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())); |
| LValue RHS; |
| RHS.setFrom(Info.Ctx, ArgValues[0]); |
| APValue RHSValue; |
| if (!handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(), |
| RHS, RHSValue)) |
| return false; |
| if (!handleAssignment(Info, Args[0], *This, MD->getThisType(Info.Ctx), |
| RHSValue)) |
| return false; |
| This->moveInto(Result); |
| return true; |
| } |
| |
| EvalStmtResult ESR = EvaluateStmt(Result, Info, Body); |
| if (ESR == ESR_Succeeded) { |
| if (Callee->getResultType()->isVoidType()) |
| return true; |
| Info.Diag(Callee->getLocEnd(), diag::note_constexpr_no_return); |
| } |
| return ESR == ESR_Returned; |
| } |
| |
| /// Evaluate a constructor call. |
| static bool HandleConstructorCall(SourceLocation CallLoc, const LValue &This, |
| ArrayRef<const Expr*> Args, |
| const CXXConstructorDecl *Definition, |
| EvalInfo &Info, APValue &Result) { |
| ArgVector ArgValues(Args.size()); |
| if (!EvaluateArgs(Args, ArgValues, Info)) |
| return false; |
| |
| if (!Info.CheckCallLimit(CallLoc)) |
| return false; |
| |
| const CXXRecordDecl *RD = Definition->getParent(); |
| if (RD->getNumVBases()) { |
| Info.Diag(CallLoc, diag::note_constexpr_virtual_base) << RD; |
| return false; |
| } |
| |
| CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues.data()); |
| |
| // If it's a delegating constructor, just delegate. |
| if (Definition->isDelegatingConstructor()) { |
| CXXConstructorDecl::init_const_iterator I = Definition->init_begin(); |
| { |
| FullExpressionRAII InitScope(Info); |
| if (!EvaluateInPlace(Result, Info, This, (*I)->getInit())) |
| return false; |
| } |
| return EvaluateStmt(Result, Info, Definition->getBody()) != ESR_Failed; |
| } |
| |
| // For a trivial copy or move constructor, perform an APValue copy. This is |
| // essential for unions, where the operations performed by the constructor |
| // cannot be represented by ctor-initializers. |
| if (Definition->isDefaulted() && |
| ((Definition->isCopyConstructor() && Definition->isTrivial()) || |
| (Definition->isMoveConstructor() && Definition->isTrivial()))) { |
| LValue RHS; |
| RHS.setFrom(Info.Ctx, ArgValues[0]); |
| return handleLValueToRValueConversion(Info, Args[0], Args[0]->getType(), |
| RHS, Result); |
| } |
| |
| // Reserve space for the struct members. |
| if (!RD->isUnion() && Result.isUninit()) |
| Result = APValue(APValue::UninitStruct(), RD->getNumBases(), |
| std::distance(RD->field_begin(), RD->field_end())); |
| |
| if (RD->isInvalidDecl()) return false; |
| const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); |
| |
| // A scope for temporaries lifetime-extended by reference members. |
| BlockScopeRAII LifetimeExtendedScope(Info); |
| |
| bool Success = true; |
| unsigned BasesSeen = 0; |
| #ifndef NDEBUG |
| CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin(); |
| #endif |
| for (CXXConstructorDecl::init_const_iterator I = Definition->init_begin(), |
| E = Definition->init_end(); I != E; ++I) { |
| LValue Subobject = This; |
| APValue *Value = &Result; |
| |
| // Determine the subobject to initialize. |
| FieldDecl *FD = 0; |
| if ((*I)->isBaseInitializer()) { |
| QualType BaseType((*I)->getBaseClass(), 0); |
| #ifndef NDEBUG |
| // Non-virtual base classes are initialized in the order in the class |
| // definition. We have already checked for virtual base classes. |
| assert(!BaseIt->isVirtual() && "virtual base for literal type"); |
| assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) && |
| "base class initializers not in expected order"); |
| ++BaseIt; |
| #endif |
| if (!HandleLValueDirectBase(Info, (*I)->getInit(), Subobject, RD, |
| BaseType->getAsCXXRecordDecl(), &Layout)) |
| return false; |
| Value = &Result.getStructBase(BasesSeen++); |
| } else if ((FD = (*I)->getMember())) { |
| if (!HandleLValueMember(Info, (*I)->getInit(), Subobject, FD, &Layout)) |
| return false; |
| if (RD->isUnion()) { |
| Result = APValue(FD); |
| Value = &Result.getUnionValue(); |
| } else { |
| Value = &Result.getStructField(FD->getFieldIndex()); |
| } |
| } else if (IndirectFieldDecl *IFD = (*I)->getIndirectMember()) { |
| // Walk the indirect field decl's chain to find the object to initialize, |
| // and make sure we've initialized every step along it. |
| for (IndirectFieldDecl::chain_iterator C = IFD->chain_begin(), |
| CE = IFD->chain_end(); |
| C != CE; ++C) { |
| FD = cast<FieldDecl>(*C); |
| CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent()); |
| // Switch the union field if it differs. This happens if we had |
| // preceding zero-initialization, and we're now initializing a union |
| // subobject other than the first. |
| // FIXME: In this case, the values of the other subobjects are |
| // specified, since zero-initialization sets all padding bits to zero. |
| if (Value->isUninit() || |
| (Value->isUnion() && Value->getUnionField() != FD)) { |
| if (CD->isUnion()) |
| *Value = APValue(FD); |
| else |
| *Value = APValue(APValue::UninitStruct(), CD->getNumBases(), |
| std::distance(CD->field_begin(), CD->field_end())); |
| } |
| if (!HandleLValueMember(Info, (*I)->getInit(), Subobject, FD)) |
| return false; |
| if (CD->isUnion()) |
| Value = &Value->getUnionValue(); |
| else |
| Value = &Value->getStructField(FD->getFieldIndex()); |
| } |
| } else { |
| llvm_unreachable("unknown base initializer kind"); |
| } |
| |
| FullExpressionRAII InitScope(Info); |
| if (!EvaluateInPlace(*Value, Info, Subobject, (*I)->getInit()) || |
| (FD && FD->isBitField() && !truncateBitfieldValue(Info, (*I)->getInit(), |
| *Value, FD))) { |
| // If we're checking for a potential constant expression, evaluate all |
| // initializers even if some of them fail. |
| if (!Info.keepEvaluatingAfterFailure()) |
| return false; |
| Success = false; |
| } |
| } |
| |
| return Success && |
| EvaluateStmt(Result, Info, Definition->getBody()) != ESR_Failed; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Generic Evaluation |
| //===----------------------------------------------------------------------===// |
| namespace { |
| |
| // FIXME: RetTy is always bool. Remove it. |
| template <class Derived, typename RetTy=bool> |
| class ExprEvaluatorBase |
| : public ConstStmtVisitor<Derived, RetTy> { |
| private: |
| RetTy DerivedSuccess(const APValue &V, const Expr *E) { |
| return static_cast<Derived*>(this)->Success(V, E); |
| } |
| RetTy DerivedZeroInitialization(const Expr *E) { |
| return static_cast<Derived*>(this)->ZeroInitialization(E); |
| } |
| |
| // Check whether a conditional operator with a non-constant condition is a |
| // potential constant expression. If neither arm is a potential constant |
| // expression, then the conditional operator is not either. |
| template<typename ConditionalOperator> |
| void CheckPotentialConstantConditional(const ConditionalOperator *E) { |
| assert(Info.checkingPotentialConstantExpression()); |
| |
| // Speculatively evaluate both arms. |
| { |
| SmallVector<PartialDiagnosticAt, 8> Diag; |
| SpeculativeEvaluationRAII Speculate(Info, &Diag); |
| |
| StmtVisitorTy::Visit(E->getFalseExpr()); |
| if (Diag.empty()) |
| return; |
| |
| Diag.clear(); |
| StmtVisitorTy::Visit(E->getTrueExpr()); |
| if (Diag.empty()) |
| return; |
| } |
| |
| Error(E, diag::note_constexpr_conditional_never_const); |
| } |
| |
| |
| template<typename ConditionalOperator> |
| bool HandleConditionalOperator(const ConditionalOperator *E) { |
| bool BoolResult; |
| if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) { |
| if (Info.checkingPotentialConstantExpression()) |
| CheckPotentialConstantConditional(E); |
| return false; |
| } |
| |
| Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr(); |
| return StmtVisitorTy::Visit(EvalExpr); |
| } |
| |
| protected: |
| EvalInfo &Info; |
| typedef ConstStmtVisitor<Derived, RetTy> StmtVisitorTy; |
| typedef ExprEvaluatorBase ExprEvaluatorBaseTy; |
| |
| OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) { |
| return Info.CCEDiag(E, D); |
| } |
| |
| RetTy ZeroInitialization(const Expr *E) { return Error(E); } |
| |
| public: |
| ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {} |
| |
| EvalInfo &getEvalInfo() { return Info; } |
| |
| /// Report an evaluation error. This should only be called when an error is |
| /// first discovered. When propagating an error, just return false. |
| bool Error(const Expr *E, diag::kind D) { |
| Info.Diag(E, D); |
| return false; |
| } |
| bool Error(const Expr *E) { |
| return Error(E, diag::note_invalid_subexpr_in_const_expr); |
| } |
| |
| RetTy VisitStmt(const Stmt *) { |
| llvm_unreachable("Expression evaluator should not be called on stmts"); |
| } |
| RetTy VisitExpr(const Expr *E) { |
| return Error(E); |
| } |
| |
| RetTy VisitParenExpr(const ParenExpr *E) |
| { return StmtVisitorTy::Visit(E->getSubExpr()); } |
| RetTy VisitUnaryExtension(const UnaryOperator *E) |
| { return StmtVisitorTy::Visit(E->getSubExpr()); } |
| RetTy VisitUnaryPlus(const UnaryOperator *E) |
| { return StmtVisitorTy::Visit(E->getSubExpr()); } |
| RetTy VisitChooseExpr(const ChooseExpr *E) |
| { return StmtVisitorTy::Visit(E->getChosenSubExpr()); } |
| RetTy VisitGenericSelectionExpr(const GenericSelectionExpr *E) |
| { return StmtVisitorTy::Visit(E->getResultExpr()); } |
| RetTy VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E) |
| { return StmtVisitorTy::Visit(E->getReplacement()); } |
| RetTy VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) |
| { return StmtVisitorTy::Visit(E->getExpr()); } |
| RetTy VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) { |
| // The initializer may not have been parsed yet, or might be erroneous. |
| if (!E->getExpr()) |
| return Error(E); |
| return StmtVisitorTy::Visit(E->getExpr()); |
| } |
| // We cannot create any objects for which cleanups are required, so there is |
| // nothing to do here; all cleanups must come from unevaluated subexpressions. |
| RetTy VisitExprWithCleanups(const ExprWithCleanups *E) |
| { return StmtVisitorTy::Visit(E->getSubExpr()); } |
| |
| RetTy VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) { |
| CCEDiag(E, diag::note_constexpr_invalid_cast) << 0; |
| return static_cast<Derived*>(this)->VisitCastExpr(E); |
| } |
| RetTy VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) { |
| CCEDiag(E, diag::note_constexpr_invalid_cast) << 1; |
| return static_cast<Derived*>(this)->VisitCastExpr(E); |
| } |
| |
| RetTy VisitBinaryOperator(const BinaryOperator *E) { |
| switch (E->getOpcode()) { |
| default: |
| return Error(E); |
| |
| case BO_Comma: |
| VisitIgnoredValue(E->getLHS()); |
| return StmtVisitorTy::Visit(E->getRHS()); |
| |
| case BO_PtrMemD: |
| case BO_PtrMemI: { |
| LValue Obj; |
| if (!HandleMemberPointerAccess(Info, E, Obj)) |
| return false; |
| APValue Result; |
| if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result)) |
| return false; |
| return DerivedSuccess(Result, E); |
| } |
| } |
| } |
| |
| RetTy VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) { |
| // Evaluate and cache the common expression. We treat it as a temporary, |
| // even though it's not quite the same thing. |
| if (!Evaluate(Info.CurrentCall->createTemporary(E->getOpaqueValue(), false), |
| Info, E->getCommon())) |
| return false; |
| |
| return HandleConditionalOperator(E); |
| } |
| |
| RetTy VisitConditionalOperator(const ConditionalOperator *E) { |
| bool IsBcpCall = false; |
| // If the condition (ignoring parens) is a __builtin_constant_p call, |
| // the result is a constant expression if it can be folded without |
| // side-effects. This is an important GNU extension. See GCC PR38377 |
| // for discussion. |
| if (const CallExpr *CallCE = |
| dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts())) |
| if (CallCE->isBuiltinCall() == Builtin::BI__builtin_constant_p) |
| IsBcpCall = true; |
| |
| // Always assume __builtin_constant_p(...) ? ... : ... is a potential |
| // constant expression; we can't check whether it's potentially foldable. |
| if (Info.checkingPotentialConstantExpression() && IsBcpCall) |
| return false; |
| |
| FoldConstant Fold(Info, IsBcpCall); |
| if (!HandleConditionalOperator(E)) { |
| Fold.keepDiagnostics(); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| RetTy VisitOpaqueValueExpr(const OpaqueValueExpr *E) { |
| if (APValue *Value = Info.CurrentCall->getTemporary(E)) |
| return DerivedSuccess(*Value, E); |
| |
| const Expr *Source = E->getSourceExpr(); |
| if (!Source) |
| return Error(E); |
| if (Source == E) { // sanity checking. |
| assert(0 && "OpaqueValueExpr recursively refers to itself"); |
| return Error(E); |
| } |
| return StmtVisitorTy::Visit(Source); |
| } |
| |
| RetTy VisitCallExpr(const CallExpr *E) { |
| const Expr *Callee = E->getCallee()->IgnoreParens(); |
| QualType CalleeType = Callee->getType(); |
| |
| const FunctionDecl *FD = 0; |
| LValue *This = 0, ThisVal; |
| ArrayRef<const Expr *> Args(E->getArgs(), E->getNumArgs()); |
| bool HasQualifier = false; |
| |
| // Extract function decl and 'this' pointer from the callee. |
| if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) { |
| const ValueDecl *Member = 0; |
| if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) { |
| // Explicit bound member calls, such as x.f() or p->g(); |
| if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal)) |
| return false; |
| Member = ME->getMemberDecl(); |
| This = &ThisVal; |
| HasQualifier = ME->hasQualifier(); |
| } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) { |
| // Indirect bound member calls ('.*' or '->*'). |
| Member = HandleMemberPointerAccess(Info, BE, ThisVal, false); |
| if (!Member) return false; |
| This = &ThisVal; |
| } else |
| return Error(Callee); |
| |
| FD = dyn_cast<FunctionDecl>(Member); |
| if (!FD) |
| return Error(Callee); |
| } else if (CalleeType->isFunctionPointerType()) { |
| LValue Call; |
| if (!EvaluatePointer(Callee, Call, Info)) |
| return false; |
| |
| if (!Call.getLValueOffset().isZero()) |
| return Error(Callee); |
| FD = dyn_cast_or_null<FunctionDecl>( |
| Call.getLValueBase().dyn_cast<const ValueDecl*>()); |
| if (!FD) |
| return Error(Callee); |
| |
| // Overloaded operator calls to member functions are represented as normal |
| // calls with '*this' as the first argument. |
| const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); |
| if (MD && !MD->isStatic()) { |
| // FIXME: When selecting an implicit conversion for an overloaded |
| // operator delete, we sometimes try to evaluate calls to conversion |
| // operators without a 'this' parameter! |
| if (Args.empty()) |
| return Error(E); |
| |
| if (!EvaluateObjectArgument(Info, Args[0], ThisVal)) |
| return false; |
| This = &ThisVal; |
| Args = Args.slice(1); |
| } |
| |
| // Don't call function pointers which have been cast to some other type. |
| if (!Info.Ctx.hasSameType(CalleeType->getPointeeType(), FD->getType())) |
| return Error(E); |
| } else |
| return Error(E); |
| |
| if (This && !This->checkSubobject(Info, E, CSK_This)) |
| return false; |
| |
| // DR1358 allows virtual constexpr functions in some cases. Don't allow |
| // calls to such functions in constant expressions. |
| if (This && !HasQualifier && |
| isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isVirtual()) |
| return Error(E, diag::note_constexpr_virtual_call); |
| |
| const FunctionDecl *Definition = 0; |
| Stmt *Body = FD->getBody(Definition); |
| APValue Result; |
| |
| if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition) || |
| !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, |
| Info, Result)) |
| return false; |
| |
| return DerivedSuccess(Result, E); |
| } |
| |
| RetTy VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { |
| return StmtVisitorTy::Visit(E->getInitializer()); |
| } |
| RetTy VisitInitListExpr(const InitListExpr *E) { |
| if (E->getNumInits() == 0) |
| return DerivedZeroInitialization(E); |
| if (E->getNumInits() == 1) |
| return StmtVisitorTy::Visit(E->getInit(0)); |
| return Error(E); |
| } |
| RetTy VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { |
| return DerivedZeroInitialization(E); |
| } |
| RetTy VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) { |
| return DerivedZeroInitialization(E); |
| } |
| RetTy VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) { |
| return DerivedZeroInitialization(E); |
| } |
| |
| /// A member expression where the object is a prvalue is itself a prvalue. |
| RetTy VisitMemberExpr(const MemberExpr *E) { |
| assert(!E->isArrow() && "missing call to bound member function?"); |
| |
| APValue Val; |
| if (!Evaluate(Val, Info, E->getBase())) |
| return false; |
| |
| QualType BaseTy = E->getBase()->getType(); |
| |
| const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl()); |
| if (!FD) return Error(E); |
| assert(!FD->getType()->isReferenceType() && "prvalue reference?"); |
| assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() == |
| FD->getParent()->getCanonicalDecl() && "record / field mismatch"); |
| |
| CompleteObject Obj(&Val, BaseTy); |
| SubobjectDesignator Designator(BaseTy); |
| Designator.addDeclUnchecked(FD); |
| |
| APValue Result; |
| return extractSubobject(Info, E, Obj, Designator, Result) && |
| DerivedSuccess(Result, E); |
| } |
| |
| RetTy VisitCastExpr(const CastExpr *E) { |
| switch (E->getCastKind()) { |
| default: |
| break; |
| |
| case CK_AtomicToNonAtomic: { |
| APValue AtomicVal; |
| if (!EvaluateAtomic(E->getSubExpr(), AtomicVal, Info)) |
| return false; |
| return DerivedSuccess(AtomicVal, E); |
| } |
| |
| case CK_NoOp: |
| case CK_UserDefinedConversion: |
| return StmtVisitorTy::Visit(E->getSubExpr()); |
| |
| case CK_LValueToRValue: { |
| LValue LVal; |
| if (!EvaluateLValue(E->getSubExpr(), LVal, Info)) |
| return false; |
| APValue RVal; |
| // Note, we use the subexpression's type in order to retain cv-qualifiers. |
| if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(), |
| LVal, RVal)) |
| return false; |
| return DerivedSuccess(RVal, E); |
| } |
| } |
| |
| return Error(E); |
| } |
| |
| RetTy VisitUnaryPostInc(const UnaryOperator *UO) { |
| return VisitUnaryPostIncDec(UO); |
| } |
| RetTy VisitUnaryPostDec(const UnaryOperator *UO) { |
| return VisitUnaryPostIncDec(UO); |
| } |
| RetTy VisitUnaryPostIncDec(const UnaryOperator *UO) { |
| if (!Info.getLangOpts().CPlusPlus1y && !Info.keepEvaluatingAfterFailure()) |
| return Error(UO); |
| |
| LValue LVal; |
| if (!EvaluateLValue(UO->getSubExpr(), LVal, Info)) |
| return false; |
| APValue RVal; |
| if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(), |
| UO->isIncrementOp(), &RVal)) |
| return false; |
| return DerivedSuccess(RVal, UO); |
| } |
| |
| RetTy VisitStmtExpr(const StmtExpr *E) { |
| // We will have checked the full-expressions inside the statement expression |
| // when they were completed, and don't need to check them again now. |
| if (Info.checkingForOverflow()) |
| return Error(E); |
| |
| BlockScopeRAII Scope(Info); |
| const CompoundStmt *CS = E->getSubStmt(); |
| for (CompoundStmt::const_body_iterator BI = CS->body_begin(), |
| BE = CS->body_end(); |
| /**/; ++BI) { |
| if (BI + 1 == BE) { |
| const Expr *FinalExpr = dyn_cast<Expr>(*BI); |
| if (!FinalExpr) { |
| Info.Diag((*BI)->getLocStart(), |
| diag::note_constexpr_stmt_expr_unsupported); |
| return false; |
| } |
| return this->Visit(FinalExpr); |
| } |
| |
| APValue ReturnValue; |
| EvalStmtResult ESR = EvaluateStmt(ReturnValue, Info, *BI); |
| if (ESR != ESR_Succeeded) { |
| // FIXME: If the statement-expression terminated due to 'return', |
| // 'break', or 'continue', it would be nice to propagate that to |
| // the outer statement evaluation rather than bailing out. |
| if (ESR != ESR_Failed) |
| Info.Diag((*BI)->getLocStart(), |
| diag::note_constexpr_stmt_expr_unsupported); |
| return false; |
| } |
| } |
| } |
| |
| /// Visit a value which is evaluated, but whose value is ignored. |
| void VisitIgnoredValue(const Expr *E) { |
| EvaluateIgnoredValue(Info, E); |
| } |
| }; |
| |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Common base class for lvalue and temporary evaluation. |
| //===----------------------------------------------------------------------===// |
| namespace { |
| template<class Derived> |
| class LValueExprEvaluatorBase |
| : public ExprEvaluatorBase<Derived, bool> { |
| protected: |
| LValue &Result; |
| typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy; |
| typedef ExprEvaluatorBase<Derived, bool> ExprEvaluatorBaseTy; |
| |
| bool Success(APValue::LValueBase B) { |
| Result.set(B); |
| return true; |
| } |
| |
| public: |
| LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result) : |
| ExprEvaluatorBaseTy(Info), Result(Result) {} |
| |
| bool Success(const APValue &V, const Expr *E) { |
| Result.setFrom(this->Info.Ctx, V); |
| return true; |
| } |
| |
| bool VisitMemberExpr(const MemberExpr *E) { |
| // Handle non-static data members. |
| QualType BaseTy; |
| if (E->isArrow()) { |
| if (!EvaluatePointer(E->getBase(), Result, this->Info)) |
| return false; |
| BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType(); |
| } else if (E->getBase()->isRValue()) { |
| assert(E->getBase()->getType()->isRecordType()); |
| if (!EvaluateTemporary(E->getBase(), Result, this->Info)) |
| return false; |
| BaseTy = E->getBase()->getType(); |
| } else { |
| if (!this->Visit(E->getBase())) |
| return false; |
| BaseTy = E->getBase()->getType(); |
| } |
| |
| const ValueDecl *MD = E->getMemberDecl(); |
| if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) { |
| assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() == |
| FD->getParent()->getCanonicalDecl() && "record / field mismatch"); |
| (void)BaseTy; |
| if (!HandleLValueMember(this->Info, E, Result, FD)) |
| return false; |
| } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) { |
| if (!HandleLValueIndirectMember(this->Info, E, Result, IFD)) |
| return false; |
| } else |
| return this->Error(E); |
| |
| if (MD->getType()->isReferenceType()) { |
| APValue RefValue; |
| if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result, |
| RefValue)) |
| return false; |
| return Success(RefValue, E); |
| } |
| return true; |
| } |
| |
| bool VisitBinaryOperator(const BinaryOperator *E) { |
| switch (E->getOpcode()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitBinaryOperator(E); |
| |
| case BO_PtrMemD: |
| case BO_PtrMemI: |
| return HandleMemberPointerAccess(this->Info, E, Result); |
| } |
| } |
| |
| bool VisitCastExpr(const CastExpr *E) { |
| switch (E->getCastKind()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| |
| case CK_DerivedToBase: |
| case CK_UncheckedDerivedToBase: |
| if (!this->Visit(E->getSubExpr())) |
| return false; |
| |
| // Now figure out the necessary offset to add to the base LV to get from |
| // the derived class to the base class. |
| return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(), |
| Result); |
| } |
| } |
| }; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // LValue Evaluation |
| // |
| // This is used for evaluating lvalues (in C and C++), xvalues (in C++11), |
| // function designators (in C), decl references to void objects (in C), and |
| // temporaries (if building with -Wno-address-of-temporary). |
| // |
| // LValue evaluation produces values comprising a base expression of one of the |
| // following types: |
| // - Declarations |
| // * VarDecl |
| // * FunctionDecl |
| // - Literals |
| // * CompoundLiteralExpr in C |
| // * StringLiteral |
| // * CXXTypeidExpr |
| // * PredefinedExpr |
| // * ObjCStringLiteralExpr |
| // * ObjCEncodeExpr |
| // * AddrLabelExpr |
| // * BlockExpr |
| // * CallExpr for a MakeStringConstant builtin |
| // - Locals and temporaries |
| // * MaterializeTemporaryExpr |
| // * Any Expr, with a CallIndex indicating the function in which the temporary |
| // was evaluated, for cases where the MaterializeTemporaryExpr is missing |
| // from the AST (FIXME). |
| // * A MaterializeTemporaryExpr that has static storage duration, with no |
| // CallIndex, for a lifetime-extended temporary. |
| // plus an offset in bytes. |
| //===----------------------------------------------------------------------===// |
| namespace { |
| class LValueExprEvaluator |
| : public LValueExprEvaluatorBase<LValueExprEvaluator> { |
| public: |
| LValueExprEvaluator(EvalInfo &Info, LValue &Result) : |
| LValueExprEvaluatorBaseTy(Info, Result) {} |
| |
| bool VisitVarDecl(const Expr *E, const VarDecl *VD); |
| bool VisitUnaryPreIncDec(const UnaryOperator *UO); |
| |
| bool VisitDeclRefExpr(const DeclRefExpr *E); |
| bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); } |
| bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E); |
| bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E); |
| bool VisitMemberExpr(const MemberExpr *E); |
| bool VisitStringLiteral(const StringLiteral *E) { return Success(E); } |
| bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); } |
| bool VisitCXXTypeidExpr(const CXXTypeidExpr *E); |
| bool VisitCXXUuidofExpr(const CXXUuidofExpr *E); |
| bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E); |
| bool VisitUnaryDeref(const UnaryOperator *E); |
| bool VisitUnaryReal(const UnaryOperator *E); |
| bool VisitUnaryImag(const UnaryOperator *E); |
| bool VisitUnaryPreInc(const UnaryOperator *UO) { |
| return VisitUnaryPreIncDec(UO); |
| } |
| bool VisitUnaryPreDec(const UnaryOperator *UO) { |
| return VisitUnaryPreIncDec(UO); |
| } |
| bool VisitBinAssign(const BinaryOperator *BO); |
| bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO); |
| |
| bool VisitCastExpr(const CastExpr *E) { |
| switch (E->getCastKind()) { |
| default: |
| return LValueExprEvaluatorBaseTy::VisitCastExpr(E); |
| |
| case CK_LValueBitCast: |
| this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; |
| if (!Visit(E->getSubExpr())) |
| return false; |
| Result.Designator.setInvalid(); |
| return true; |
| |
| case CK_BaseToDerived: |
| if (!Visit(E->getSubExpr())) |
| return false; |
| return HandleBaseToDerivedCast(Info, E, Result); |
| } |
| } |
| }; |
| } // end anonymous namespace |
| |
| /// Evaluate an expression as an lvalue. This can be legitimately called on |
| /// expressions which are not glvalues, in two cases: |
| /// * function designators in C, and |
| /// * "extern void" objects |
| static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info) { |
| assert(E->isGLValue() || E->getType()->isFunctionType() || |
| E->getType()->isVoidType()); |
| return LValueExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) { |
| if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) |
| return Success(FD); |
| if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl())) |
| return VisitVarDecl(E, VD); |
| return Error(E); |
| } |
| |
| bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) { |
| CallStackFrame *Frame = 0; |
| if (VD->hasLocalStorage() && Info.CurrentCall->Index > 1) |
| Frame = Info.CurrentCall; |
| |
| if (!VD->getType()->isReferenceType()) { |
| if (Frame) { |
| Result.set(VD, Frame->Index); |
| return true; |
| } |
| return Success(VD); |
| } |
| |
| APValue *V; |
| if (!evaluateVarDeclInit(Info, E, VD, Frame, V)) |
| return false; |
| if (V->isUninit()) { |
| if (!Info.checkingPotentialConstantExpression()) |
| Info.Diag(E, diag::note_constexpr_use_uninit_reference); |
| return false; |
| } |
| return Success(*V, E); |
| } |
| |
| bool LValueExprEvaluator::VisitMaterializeTemporaryExpr( |
| const MaterializeTemporaryExpr *E) { |
| // Walk through the expression to find the materialized temporary itself. |
| SmallVector<const Expr *, 2> CommaLHSs; |
| SmallVector<SubobjectAdjustment, 2> Adjustments; |
| const Expr *Inner = E->GetTemporaryExpr()-> |
| skipRValueSubobjectAdjustments(CommaLHSs, Adjustments); |
| |
| // If we passed any comma operators, evaluate their LHSs. |
| for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I) |
| if (!EvaluateIgnoredValue(Info, CommaLHSs[I])) |
| return false; |
| |
| // A materialized temporary with static storage duration can appear within the |
| // result of a constant expression evaluation, so we need to preserve its |
| // value for use outside this evaluation. |
| APValue *Value; |
| if (E->getStorageDuration() == SD_Static) { |
| Value = Info.Ctx.getMaterializedTemporaryValue(E, true); |
| *Value = APValue(); |
| Result.set(E); |
| } else { |
| Value = &Info.CurrentCall-> |
| createTemporary(E, E->getStorageDuration() == SD_Automatic); |
| Result.set(E, Info.CurrentCall->Index); |
| } |
| |
| QualType Type = Inner->getType(); |
| |
| // Materialize the temporary itself. |
| if (!EvaluateInPlace(*Value, Info, Result, Inner) || |
| (E->getStorageDuration() == SD_Static && |
| !CheckConstantExpression(Info, E->getExprLoc(), Type, *Value))) { |
| *Value = APValue(); |
| return false; |
| } |
| |
| // Adjust our lvalue to refer to the desired subobject. |
| for (unsigned I = Adjustments.size(); I != 0; /**/) { |
| --I; |
| switch (Adjustments[I].Kind) { |
| case SubobjectAdjustment::DerivedToBaseAdjustment: |
| if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath, |
| Type, Result)) |
| return false; |
| Type = Adjustments[I].DerivedToBase.BasePath->getType(); |
| break; |
| |
| case SubobjectAdjustment::FieldAdjustment: |
| if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field)) |
| return false; |
| Type = Adjustments[I].Field->getType(); |
| break; |
| |
| case SubobjectAdjustment::MemberPointerAdjustment: |
| if (!HandleMemberPointerAccess(this->Info, Type, Result, |
| Adjustments[I].Ptr.RHS)) |
| return false; |
| Type = Adjustments[I].Ptr.MPT->getPointeeType(); |
| break; |
| } |
| } |
| |
| return true; |
| } |
| |
| bool |
| LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { |
| assert(!Info.getLangOpts().CPlusPlus && "lvalue compound literal in c++?"); |
| // Defer visiting the literal until the lvalue-to-rvalue conversion. We can |
| // only see this when folding in C, so there's no standard to follow here. |
| return Success(E); |
| } |
| |
| bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) { |
| if (!E->isPotentiallyEvaluated()) |
| return Success(E); |
| |
| Info.Diag(E, diag::note_constexpr_typeid_polymorphic) |
| << E->getExprOperand()->getType() |
| << E->getExprOperand()->getSourceRange(); |
| return false; |
| } |
| |
| bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) { |
| return Success(E); |
| } |
| |
| bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) { |
| // Handle static data members. |
| if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) { |
| VisitIgnoredValue(E->getBase()); |
| return VisitVarDecl(E, VD); |
| } |
| |
| // Handle static member functions. |
| if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) { |
| if (MD->isStatic()) { |
| VisitIgnoredValue(E->getBase()); |
| return Success(MD); |
| } |
| } |
| |
| // Handle non-static data members. |
| return LValueExprEvaluatorBaseTy::VisitMemberExpr(E); |
| } |
| |
| bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) { |
| // FIXME: Deal with vectors as array subscript bases. |
| if (E->getBase()->getType()->isVectorType()) |
| return Error(E); |
| |
| if (!EvaluatePointer(E->getBase(), Result, Info)) |
| return false; |
| |
| APSInt Index; |
| if (!EvaluateInteger(E->getIdx(), Index, Info)) |
| return false; |
| |
| return HandleLValueArrayAdjustment(Info, E, Result, E->getType(), |
| getExtValue(Index)); |
| } |
| |
| bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) { |
| return EvaluatePointer(E->getSubExpr(), Result, Info); |
| } |
| |
| bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { |
| if (!Visit(E->getSubExpr())) |
| return false; |
| // __real is a no-op on scalar lvalues. |
| if (E->getSubExpr()->getType()->isAnyComplexType()) |
| HandleLValueComplexElement(Info, E, Result, E->getType(), false); |
| return true; |
| } |
| |
| bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { |
| assert(E->getSubExpr()->getType()->isAnyComplexType() && |
| "lvalue __imag__ on scalar?"); |
| if (!Visit(E->getSubExpr())) |
| return false; |
| HandleLValueComplexElement(Info, E, Result, E->getType(), true); |
| return true; |
| } |
| |
| bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) { |
| if (!Info.getLangOpts().CPlusPlus1y && !Info.keepEvaluatingAfterFailure()) |
| return Error(UO); |
| |
| if (!this->Visit(UO->getSubExpr())) |
| return false; |
| |
| return handleIncDec( |
| this->Info, UO, Result, UO->getSubExpr()->getType(), |
| UO->isIncrementOp(), 0); |
| } |
| |
| bool LValueExprEvaluator::VisitCompoundAssignOperator( |
| const CompoundAssignOperator *CAO) { |
| if (!Info.getLangOpts().CPlusPlus1y && !Info.keepEvaluatingAfterFailure()) |
| return Error(CAO); |
| |
| APValue RHS; |
| |
| // The overall lvalue result is the result of evaluating the LHS. |
| if (!this->Visit(CAO->getLHS())) { |
| if (Info.keepEvaluatingAfterFailure()) |
| Evaluate(RHS, this->Info, CAO->getRHS()); |
| return false; |
| } |
| |
| if (!Evaluate(RHS, this->Info, CAO->getRHS())) |
| return false; |
| |
| return handleCompoundAssignment( |
| this->Info, CAO, |
| Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(), |
| CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS); |
| } |
| |
| bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) { |
| if (!Info.getLangOpts().CPlusPlus1y && !Info.keepEvaluatingAfterFailure()) |
| return Error(E); |
| |
| APValue NewVal; |
| |
| if (!this->Visit(E->getLHS())) { |
| if (Info.keepEvaluatingAfterFailure()) |
| Evaluate(NewVal, this->Info, E->getRHS()); |
| return false; |
| } |
| |
| if (!Evaluate(NewVal, this->Info, E->getRHS())) |
| return false; |
| |
| return handleAssignment(this->Info, E, Result, E->getLHS()->getType(), |
| NewVal); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Pointer Evaluation |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class PointerExprEvaluator |
| : public ExprEvaluatorBase<PointerExprEvaluator, bool> { |
| LValue &Result; |
| |
| bool Success(const Expr *E) { |
| Result.set(E); |
| return true; |
| } |
| public: |
| |
| PointerExprEvaluator(EvalInfo &info, LValue &Result) |
| : ExprEvaluatorBaseTy(info), Result(Result) {} |
| |
| bool Success(const APValue &V, const Expr *E) { |
| Result.setFrom(Info.Ctx, V); |
| return true; |
| } |
| bool ZeroInitialization(const Expr *E) { |
| return Success((Expr*)0); |
| } |
| |
| bool VisitBinaryOperator(const BinaryOperator *E); |
| bool VisitCastExpr(const CastExpr* E); |
| bool VisitUnaryAddrOf(const UnaryOperator *E); |
| bool VisitObjCStringLiteral(const ObjCStringLiteral *E) |
| { return Success(E); } |
| bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) |
| { return Success(E); } |
| bool VisitAddrLabelExpr(const AddrLabelExpr *E) |
| { return Success(E); } |
| bool VisitCallExpr(const CallExpr *E); |
| bool VisitBlockExpr(const BlockExpr *E) { |
| if (!E->getBlockDecl()->hasCaptures()) |
| return Success(E); |
| return Error(E); |
| } |
| bool VisitCXXThisExpr(const CXXThisExpr *E) { |
| // Can't look at 'this' when checking a potential constant expression. |
| if (Info.checkingPotentialConstantExpression()) |
| return false; |
| if (!Info.CurrentCall->This) |
| return Error(E); |
| Result = *Info.CurrentCall->This; |
| return true; |
| } |
| |
| // FIXME: Missing: @protocol, @selector |
| }; |
| } // end anonymous namespace |
| |
| static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->hasPointerRepresentation()); |
| return PointerExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { |
| if (E->getOpcode() != BO_Add && |
| E->getOpcode() != BO_Sub) |
| return ExprEvaluatorBaseTy::VisitBinaryOperator(E); |
| |
| const Expr *PExp = E->getLHS(); |
| const Expr *IExp = E->getRHS(); |
| if (IExp->getType()->isPointerType()) |
| std::swap(PExp, IExp); |
| |
| bool EvalPtrOK = EvaluatePointer(PExp, Result, Info); |
| if (!EvalPtrOK && !Info.keepEvaluatingAfterFailure()) |
| return false; |
| |
| llvm::APSInt Offset; |
| if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK) |
| return false; |
| |
| int64_t AdditionalOffset = getExtValue(Offset); |
| if (E->getOpcode() == BO_Sub) |
| AdditionalOffset = -AdditionalOffset; |
| |
| QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType(); |
| return HandleLValueArrayAdjustment(Info, E, Result, Pointee, |
| AdditionalOffset); |
| } |
| |
| bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { |
| return EvaluateLValue(E->getSubExpr(), Result, Info); |
| } |
| |
| bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) { |
| const Expr* SubExpr = E->getSubExpr(); |
| |
| switch (E->getCastKind()) { |
| default: |
| break; |
| |
| case CK_BitCast: |
| case CK_CPointerToObjCPointerCast: |
| case CK_BlockPointerToObjCPointerCast: |
| case CK_AnyPointerToBlockPointerCast: |
| if (!Visit(SubExpr)) |
| return false; |
| // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are |
| // permitted in constant expressions in C++11. Bitcasts from cv void* are |
| // also static_casts, but we disallow them as a resolution to DR1312. |
| if (!E->getType()->isVoidPointerType()) { |
| Result.Designator.setInvalid(); |
| if (SubExpr->getType()->isVoidPointerType()) |
| CCEDiag(E, diag::note_constexpr_invalid_cast) |
| << 3 << SubExpr->getType(); |
| else |
| CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; |
| } |
| return true; |
| |
| case CK_DerivedToBase: |
| case CK_UncheckedDerivedToBase: |
| if (!EvaluatePointer(E->getSubExpr(), Result, Info)) |
| return false; |
| if (!Result.Base && Result.Offset.isZero()) |
| return true; |
| |
| // Now figure out the necessary offset to add to the base LV to get from |
| // the derived class to the base class. |
| return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()-> |
| castAs<PointerType>()->getPointeeType(), |
| Result); |
| |
| case CK_BaseToDerived: |
| if (!Visit(E->getSubExpr())) |
| return false; |
| if (!Result.Base && Result.Offset.isZero()) |
| return true; |
| return HandleBaseToDerivedCast(Info, E, Result); |
| |
| case CK_NullToPointer: |
| VisitIgnoredValue(E->getSubExpr()); |
| return ZeroInitialization(E); |
| |
| case CK_IntegralToPointer: { |
| CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; |
| |
| APValue Value; |
| if (!EvaluateIntegerOrLValue(SubExpr, Value, Info)) |
| break; |
| |
| if (Value.isInt()) { |
| unsigned Size = Info.Ctx.getTypeSize(E->getType()); |
| uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue(); |
| Result.Base = (Expr*)0; |
| Result.Offset = CharUnits::fromQuantity(N); |
| Result.CallIndex = 0; |
| Result.Designator.setInvalid(); |
| return true; |
| } else { |
| // Cast is of an lvalue, no need to change value. |
| Result.setFrom(Info.Ctx, Value); |
| return true; |
| } |
| } |
| case CK_ArrayToPointerDecay: |
| if (SubExpr->isGLValue()) { |
| if (!EvaluateLValue(SubExpr, Result, Info)) |
| return false; |
| } else { |
| Result.set(SubExpr, Info.CurrentCall->Index); |
| if (!EvaluateInPlace(Info.CurrentCall->createTemporary(SubExpr, false), |
| Info, Result, SubExpr)) |
| return false; |
| } |
| // The result is a pointer to the first element of the array. |
| if (const ConstantArrayType *CAT |
| = Info.Ctx.getAsConstantArrayType(SubExpr->getType())) |
| Result.addArray(Info, E, CAT); |
| else |
| Result.Designator.setInvalid(); |
| return true; |
| |
| case CK_FunctionToPointerDecay: |
| return EvaluateLValue(SubExpr, Result, Info); |
| } |
| |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| } |
| |
| bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) { |
| if (IsStringLiteralCall(E)) |
| return Success(E); |
| |
| switch (E->isBuiltinCall()) { |
| case Builtin::BI__builtin_addressof: |
| return EvaluateLValue(E->getArg(0), Result, Info); |
| |
| default: |
| return ExprEvaluatorBaseTy::VisitCallExpr(E); |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Member Pointer Evaluation |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class MemberPointerExprEvaluator |
| : public ExprEvaluatorBase<MemberPointerExprEvaluator, bool> { |
| MemberPtr &Result; |
| |
| bool Success(const ValueDecl *D) { |
| Result = MemberPtr(D); |
| return true; |
| } |
| public: |
| |
| MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result) |
| : ExprEvaluatorBaseTy(Info), Result(Result) {} |
| |
| bool Success(const APValue &V, const Expr *E) { |
| Result.setFrom(V); |
| return true; |
| } |
| bool ZeroInitialization(const Expr *E) { |
| return Success((const ValueDecl*)0); |
| } |
| |
| bool VisitCastExpr(const CastExpr *E); |
| bool VisitUnaryAddrOf(const UnaryOperator *E); |
| }; |
| } // end anonymous namespace |
| |
| static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, |
| EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isMemberPointerType()); |
| return MemberPointerExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) { |
| switch (E->getCastKind()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| |
| case CK_NullToMemberPointer: |
| VisitIgnoredValue(E->getSubExpr()); |
| return ZeroInitialization(E); |
| |
| case CK_BaseToDerivedMemberPointer: { |
| if (!Visit(E->getSubExpr())) |
| return false; |
| if (E->path_empty()) |
| return true; |
| // Base-to-derived member pointer casts store the path in derived-to-base |
| // order, so iterate backwards. The CXXBaseSpecifier also provides us with |
| // the wrong end of the derived->base arc, so stagger the path by one class. |
| typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter; |
| for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin()); |
| PathI != PathE; ++PathI) { |
| assert(!(*PathI)->isVirtual() && "memptr cast through vbase"); |
| const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl(); |
| if (!Result.castToDerived(Derived)) |
| return Error(E); |
| } |
| const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass(); |
| if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl())) |
| return Error(E); |
| return true; |
| } |
| |
| case CK_DerivedToBaseMemberPointer: |
| if (!Visit(E->getSubExpr())) |
| return false; |
| for (CastExpr::path_const_iterator PathI = E->path_begin(), |
| PathE = E->path_end(); PathI != PathE; ++PathI) { |
| assert(!(*PathI)->isVirtual() && "memptr cast through vbase"); |
| const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl(); |
| if (!Result.castToBase(Base)) |
| return Error(E); |
| } |
| return true; |
| } |
| } |
| |
| bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { |
| // C++11 [expr.unary.op]p3 has very strict rules on how the address of a |
| // member can be formed. |
| return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl()); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Record Evaluation |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class RecordExprEvaluator |
| : public ExprEvaluatorBase<RecordExprEvaluator, bool> { |
| const LValue &This; |
| APValue &Result; |
| public: |
| |
| RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result) |
| : ExprEvaluatorBaseTy(info), This(This), Result(Result) {} |
| |
| bool Success(const APValue &V, const Expr *E) { |
| Result = V; |
| return true; |
| } |
| bool ZeroInitialization(const Expr *E); |
| |
| bool VisitCastExpr(const CastExpr *E); |
| bool VisitInitListExpr(const InitListExpr *E); |
| bool VisitCXXConstructExpr(const CXXConstructExpr *E); |
| bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E); |
| }; |
| } |
| |
| /// Perform zero-initialization on an object of non-union class type. |
| /// C++11 [dcl.init]p5: |
| /// To zero-initialize an object or reference of type T means: |
| /// [...] |
| /// -- if T is a (possibly cv-qualified) non-union class type, |
| /// each non-static data member and each base-class subobject is |
| /// zero-initialized |
| static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E, |
| const RecordDecl *RD, |
| const LValue &This, APValue &Result) { |
| assert(!RD->isUnion() && "Expected non-union class type"); |
| const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD); |
| Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0, |
| std::distance(RD->field_begin(), RD->field_end())); |
| |
| if (RD->isInvalidDecl()) return false; |
| const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); |
| |
| if (CD) { |
| unsigned Index = 0; |
| for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(), |
| End = CD->bases_end(); I != End; ++I, ++Index) { |
| const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl(); |
| LValue Subobject = This; |
| if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout)) |
| return false; |
| if (!HandleClassZeroInitialization(Info, E, Base, Subobject, |
| Result.getStructBase(Index))) |
| return false; |
| } |
| } |
| |
| for (RecordDecl::field_iterator I = RD->field_begin(), End = RD->field_end(); |
| I != End; ++I) { |
| // -- if T is a reference type, no initialization is performed. |
| if (I->getType()->isReferenceType()) |
| continue; |
| |
| LValue Subobject = This; |
| if (!HandleLValueMember(Info, E, Subobject, *I, &Layout)) |
| return false; |
| |
| ImplicitValueInitExpr VIE(I->getType()); |
| if (!EvaluateInPlace( |
| Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE)) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool RecordExprEvaluator::ZeroInitialization(const Expr *E) { |
| const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl(); |
| if (RD->isInvalidDecl()) return false; |
| if (RD->isUnion()) { |
| // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the |
| // object's first non-static named data member is zero-initialized |
| RecordDecl::field_iterator I = RD->field_begin(); |
| if (I == RD->field_end()) { |
| Result = APValue((const FieldDecl*)0); |
| return true; |
| } |
| |
| LValue Subobject = This; |
| if (!HandleLValueMember(Info, E, Subobject, *I)) |
| return false; |
| Result = APValue(*I); |
| ImplicitValueInitExpr VIE(I->getType()); |
| return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE); |
| } |
| |
| if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) { |
| Info.Diag(E, diag::note_constexpr_virtual_base) << RD; |
| return false; |
| } |
| |
| return HandleClassZeroInitialization(Info, E, RD, This, Result); |
| } |
| |
| bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) { |
| switch (E->getCastKind()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| |
| case CK_ConstructorConversion: |
| return Visit(E->getSubExpr()); |
| |
| case CK_DerivedToBase: |
| case CK_UncheckedDerivedToBase: { |
| APValue DerivedObject; |
| if (!Evaluate(DerivedObject, Info, E->getSubExpr())) |
| return false; |
| if (!DerivedObject.isStruct()) |
| return Error(E->getSubExpr()); |
| |
| // Derived-to-base rvalue conversion: just slice off the derived part. |
| APValue *Value = &DerivedObject; |
| const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl(); |
| for (CastExpr::path_const_iterator PathI = E->path_begin(), |
| PathE = E->path_end(); PathI != PathE; ++PathI) { |
| assert(!(*PathI)->isVirtual() && "record rvalue with virtual base"); |
| const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl(); |
| Value = &Value->getStructBase(getBaseIndex(RD, Base)); |
| RD = Base; |
| } |
| Result = *Value; |
| return true; |
| } |
| } |
| } |
| |
| bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) { |
| const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl(); |
| if (RD->isInvalidDecl()) return false; |
| const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); |
| |
| if (RD->isUnion()) { |
| const FieldDecl *Field = E->getInitializedFieldInUnion(); |
| Result = APValue(Field); |
| if (!Field) |
| return true; |
| |
| // If the initializer list for a union does not contain any elements, the |
| // first element of the union is value-initialized. |
| // FIXME: The element should be initialized from an initializer list. |
| // Is this difference ever observable for initializer lists which |
| // we don't build? |
| ImplicitValueInitExpr VIE(Field->getType()); |
| const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE; |
| |
| LValue Subobject = This; |
| if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout)) |
| return false; |
| |
| // Temporarily override This, in case there's a CXXDefaultInitExpr in here. |
| ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This, |
| isa<CXXDefaultInitExpr>(InitExpr)); |
| |
| return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr); |
| } |
| |
| assert((!isa<CXXRecordDecl>(RD) || !cast<CXXRecordDecl>(RD)->getNumBases()) && |
| "initializer list for class with base classes"); |
| Result = APValue(APValue::UninitStruct(), 0, |
| std::distance(RD->field_begin(), RD->field_end())); |
| unsigned ElementNo = 0; |
| bool Success = true; |
| for (RecordDecl::field_iterator Field = RD->field_begin(), |
| FieldEnd = RD->field_end(); Field != FieldEnd; ++Field) { |
| // Anonymous bit-fields are not considered members of the class for |
| // purposes of aggregate initialization. |
| if (Field->isUnnamedBitfield()) |
| continue; |
| |
| LValue Subobject = This; |
| |
| bool HaveInit = ElementNo < E->getNumInits(); |
| |
| // FIXME: Diagnostics here should point to the end of the initializer |
| // list, not the start. |
| if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E, |
| Subobject, *Field, &Layout)) |
| return false; |
| |
| // Perform an implicit value-initialization for members beyond the end of |
| // the initializer list. |
| ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType()); |
| const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE; |
| |
| // Temporarily override This, in case there's a CXXDefaultInitExpr in here. |
| ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This, |
| isa<CXXDefaultInitExpr>(Init)); |
| |
| APValue &FieldVal = Result.getStructField(Field->getFieldIndex()); |
| if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) || |
| (Field->isBitField() && !truncateBitfieldValue(Info, Init, |
| FieldVal, *Field))) { |
| if (!Info.keepEvaluatingAfterFailure()) |
| return false; |
| Success = false; |
| } |
| } |
| |
| return Success; |
| } |
| |
| bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) { |
| const CXXConstructorDecl *FD = E->getConstructor(); |
| if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false; |
| |
| bool ZeroInit = E->requiresZeroInitialization(); |
| if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) { |
| // If we've already performed zero-initialization, we're already done. |
| if (!Result.isUninit()) |
| return true; |
| |
| if (ZeroInit) |
| return ZeroInitialization(E); |
| |
| const CXXRecordDecl *RD = FD->getParent(); |
| if (RD->isUnion()) |
| Result = APValue((FieldDecl*)0); |
| else |
| Result = APValue(APValue::UninitStruct(), RD->getNumBases(), |
| std::distance(RD->field_begin(), RD->field_end())); |
| return true; |
| } |
| |
| const FunctionDecl *Definition = 0; |
| FD->getBody(Definition); |
| |
| if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition)) |
| return false; |
| |
| // Avoid materializing a temporary for an elidable copy/move constructor. |
| if (E->isElidable() && !ZeroInit) |
| if (const MaterializeTemporaryExpr *ME |
| = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0))) |
| return Visit(ME->GetTemporaryExpr()); |
| |
| if (ZeroInit && !ZeroInitialization(E)) |
| return false; |
| |
| ArrayRef<const Expr *> Args(E->getArgs(), E->getNumArgs()); |
| return HandleConstructorCall(E->getExprLoc(), This, Args, |
| cast<CXXConstructorDecl>(Definition), Info, |
| Result); |
| } |
| |
| bool RecordExprEvaluator::VisitCXXStdInitializerListExpr( |
| const CXXStdInitializerListExpr *E) { |
| const ConstantArrayType *ArrayType = |
| Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType()); |
| |
| LValue Array; |
| if (!EvaluateLValue(E->getSubExpr(), Array, Info)) |
| return false; |
| |
| // Get a pointer to the first element of the array. |
| Array.addArray(Info, E, ArrayType); |
| |
| // FIXME: Perform the checks on the field types in SemaInit. |
| RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl(); |
| RecordDecl::field_iterator Field = Record->field_begin(); |
| if (Field == Record->field_end()) |
| return Error(E); |
| |
| // Start pointer. |
| if (!Field->getType()->isPointerType() || |
| !Info.Ctx.hasSameType(Field->getType()->getPointeeType(), |
| ArrayType->getElementType())) |
| return Error(E); |
| |
| // FIXME: What if the initializer_list type has base classes, etc? |
| Result = APValue(APValue::UninitStruct(), 0, 2); |
| Array.moveInto(Result.getStructField(0)); |
| |
| if (++Field == Record->field_end()) |
| return Error(E); |
| |
| if (Field->getType()->isPointerType() && |
| Info.Ctx.hasSameType(Field->getType()->getPointeeType(), |
| ArrayType->getElementType())) { |
| // End pointer. |
| if (!HandleLValueArrayAdjustment(Info, E, Array, |
| ArrayType->getElementType(), |
| ArrayType->getSize().getZExtValue())) |
| return false; |
| Array.moveInto(Result.getStructField(1)); |
| } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType())) |
| // Length. |
| Result.getStructField(1) = APValue(APSInt(ArrayType->getSize())); |
| else |
| return Error(E); |
| |
| if (++Field != Record->field_end()) |
| return Error(E); |
| |
| return true; |
| } |
| |
| static bool EvaluateRecord(const Expr *E, const LValue &This, |
| APValue &Result, EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isRecordType() && |
| "can't evaluate expression as a record rvalue"); |
| return RecordExprEvaluator(Info, This, Result).Visit(E); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Temporary Evaluation |
| // |
| // Temporaries are represented in the AST as rvalues, but generally behave like |
| // lvalues. The full-object of which the temporary is a subobject is implicitly |
| // materialized so that a reference can bind to it. |
| //===----------------------------------------------------------------------===// |
| namespace { |
| class TemporaryExprEvaluator |
| : public LValueExprEvaluatorBase<TemporaryExprEvaluator> { |
| public: |
| TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) : |
| LValueExprEvaluatorBaseTy(Info, Result) {} |
| |
| /// Visit an expression which constructs the value of this temporary. |
| bool VisitConstructExpr(const Expr *E) { |
| Result.set(E, Info.CurrentCall->Index); |
| return EvaluateInPlace(Info.CurrentCall->createTemporary(E, false), |
| Info, Result, E); |
| } |
| |
| bool VisitCastExpr(const CastExpr *E) { |
| switch (E->getCastKind()) { |
| default: |
| return LValueExprEvaluatorBaseTy::VisitCastExpr(E); |
| |
| case CK_ConstructorConversion: |
| return VisitConstructExpr(E->getSubExpr()); |
| } |
| } |
| bool VisitInitListExpr(const InitListExpr *E) { |
| return VisitConstructExpr(E); |
| } |
| bool VisitCXXConstructExpr(const CXXConstructExpr *E) { |
| return VisitConstructExpr(E); |
| } |
| bool VisitCallExpr(const CallExpr *E) { |
| return VisitConstructExpr(E); |
| } |
| }; |
| } // end anonymous namespace |
| |
| /// Evaluate an expression of record type as a temporary. |
| static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isRecordType()); |
| return TemporaryExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Vector Evaluation |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class VectorExprEvaluator |
| : public ExprEvaluatorBase<VectorExprEvaluator, bool> { |
| APValue &Result; |
| public: |
| |
| VectorExprEvaluator(EvalInfo &info, APValue &Result) |
| : ExprEvaluatorBaseTy(info), Result(Result) {} |
| |
| bool Success(const ArrayRef<APValue> &V, const Expr *E) { |
| assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements()); |
| // FIXME: remove this APValue copy. |
| Result = APValue(V.data(), V.size()); |
| return true; |
| } |
| bool Success(const APValue &V, const Expr *E) { |
| assert(V.isVector()); |
| Result = V; |
| return true; |
| } |
| bool ZeroInitialization(const Expr *E); |
| |
| bool VisitUnaryReal(const UnaryOperator *E) |
| { return Visit(E->getSubExpr()); } |
| bool VisitCastExpr(const CastExpr* E); |
| bool VisitInitListExpr(const InitListExpr *E); |
| bool VisitUnaryImag(const UnaryOperator *E); |
| // FIXME: Missing: unary -, unary ~, binary add/sub/mul/div, |
| // binary comparisons, binary and/or/xor, |
| // shufflevector, ExtVectorElementExpr |
| }; |
| } // end anonymous namespace |
| |
| static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue"); |
| return VectorExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| bool VectorExprEvaluator::VisitCastExpr(const CastExpr* E) { |
| const VectorType *VTy = E->getType()->castAs<VectorType>(); |
| unsigned NElts = VTy->getNumElements(); |
| |
| const Expr *SE = E->getSubExpr(); |
| QualType SETy = SE->getType(); |
| |
| switch (E->getCastKind()) { |
| case CK_VectorSplat: { |
| APValue Val = APValue(); |
| if (SETy->isIntegerType()) { |
| APSInt IntResult; |
| if (!EvaluateInteger(SE, IntResult, Info)) |
| return false; |
| Val = APValue(IntResult); |
| } else if (SETy->isRealFloatingType()) { |
| APFloat F(0.0); |
| if (!EvaluateFloat(SE, F, Info)) |
| return false; |
| Val = APValue(F); |
| } else { |
| return Error(E); |
| } |
| |
| // Splat and create vector APValue. |
| SmallVector<APValue, 4> Elts(NElts, Val); |
| return Success(Elts, E); |
| } |
| case CK_BitCast: { |
| // Evaluate the operand into an APInt we can extract from. |
| llvm::APInt SValInt; |
| if (!EvalAndBitcastToAPInt(Info, SE, SValInt)) |
| return false; |
| // Extract the elements |
| QualType EltTy = VTy->getElementType(); |
| unsigned EltSize = Info.Ctx.getTypeSize(EltTy); |
| bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); |
| SmallVector<APValue, 4> Elts; |
| if (EltTy->isRealFloatingType()) { |
| const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy); |
| unsigned FloatEltSize = EltSize; |
| if (&Sem == &APFloat::x87DoubleExtended) |
| FloatEltSize = 80; |
| for (unsigned i = 0; i < NElts; i++) { |
| llvm::APInt Elt; |
| if (BigEndian) |
| Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize); |
| else |
| Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize); |
| Elts.push_back(APValue(APFloat(Sem, Elt))); |
| } |
| } else if (EltTy->isIntegerType()) { |
| for (unsigned i = 0; i < NElts; i++) { |
| llvm::APInt Elt; |
| if (BigEndian) |
| Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize); |
| else |
| Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize); |
| Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType()))); |
| } |
| } else { |
| return Error(E); |
| } |
| return Success(Elts, E); |
| } |
| default: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| } |
| } |
| |
| bool |
| VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) { |
| const VectorType *VT = E->getType()->castAs<VectorType>(); |
| unsigned NumInits = E->getNumInits(); |
| unsigned NumElements = VT->getNumElements(); |
| |
| QualType EltTy = VT->getElementType(); |
| SmallVector<APValue, 4> Elements; |
| |
| // The number of initializers can be less than the number of |
| // vector elements. For OpenCL, this can be due to nested vector |
| // initialization. For GCC compatibility, missing trailing elements |
| // should be initialized with zeroes. |
| unsigned CountInits = 0, CountElts = 0; |
| while (CountElts < NumElements) { |
| // Handle nested vector initialization. |
| if (CountInits < NumInits |
| && E->getInit(CountInits)->getType()->isVectorType()) { |
| APValue v; |
| if (!EvaluateVector(E->getInit(CountInits), v, Info)) |
| return Error(E); |
| unsigned vlen = v.getVectorLength(); |
| for (unsigned j = 0; j < vlen; j++) |
| Elements.push_back(v.getVectorElt(j)); |
| CountElts += vlen; |
| } else if (EltTy->isIntegerType()) { |
| llvm::APSInt sInt(32); |
| if (CountInits < NumInits) { |
| if (!EvaluateInteger(E->getInit(CountInits), sInt, Info)) |
| return false; |
| } else // trailing integer zero. |
| sInt = Info.Ctx.MakeIntValue(0, EltTy); |
| Elements.push_back(APValue(sInt)); |
| CountElts++; |
| } else { |
| llvm::APFloat f(0.0); |
| if (CountInits < NumInits) { |
| if (!EvaluateFloat(E->getInit(CountInits), f, Info)) |
| return false; |
| } else // trailing float zero. |
| f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)); |
| Elements.push_back(APValue(f)); |
| CountElts++; |
| } |
| CountInits++; |
| } |
| return Success(Elements, E); |
| } |
| |
| bool |
| VectorExprEvaluator::ZeroInitialization(const Expr *E) { |
| const VectorType *VT = E->getType()->getAs<VectorType>(); |
| QualType EltTy = VT->getElementType(); |
| APValue ZeroElement; |
| if (EltTy->isIntegerType()) |
| ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy)); |
| else |
| ZeroElement = |
| APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy))); |
| |
| SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement); |
| return Success(Elements, E); |
| } |
| |
| bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { |
| VisitIgnoredValue(E->getSubExpr()); |
| return ZeroInitialization(E); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Array Evaluation |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class ArrayExprEvaluator |
| : public ExprEvaluatorBase<ArrayExprEvaluator, bool> { |
| const LValue &This; |
| APValue &Result; |
| public: |
| |
| ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result) |
| : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {} |
| |
| bool Success(const APValue &V, const Expr *E) { |
| assert((V.isArray() || V.isLValue()) && |
| "expected array or string literal"); |
| Result = V; |
| return true; |
| } |
| |
| bool ZeroInitialization(const Expr *E) { |
| const ConstantArrayType *CAT = |
| Info.Ctx.getAsConstantArrayType(E->getType()); |
| if (!CAT) |
| return Error(E); |
| |
| Result = APValue(APValue::UninitArray(), 0, |
| CAT->getSize().getZExtValue()); |
| if (!Result.hasArrayFiller()) return true; |
| |
| // Zero-initialize all elements. |
| LValue Subobject = This; |
| Subobject.addArray(Info, E, CAT); |
| ImplicitValueInitExpr VIE(CAT->getElementType()); |
| return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE); |
| } |
| |
| bool VisitInitListExpr(const InitListExpr *E); |
| bool VisitCXXConstructExpr(const CXXConstructExpr *E); |
| bool VisitCXXConstructExpr(const CXXConstructExpr *E, |
| const LValue &Subobject, |
| APValue *Value, QualType Type); |
| }; |
| } // end anonymous namespace |
| |
| static bool EvaluateArray(const Expr *E, const LValue &This, |
| APValue &Result, EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue"); |
| return ArrayExprEvaluator(Info, This, Result).Visit(E); |
| } |
| |
| bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E) { |
| const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType()); |
| if (!CAT) |
| return Error(E); |
| |
| // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...] |
| // an appropriately-typed string literal enclosed in braces. |
| if (E->isStringLiteralInit()) { |
| LValue LV; |
| if (!EvaluateLValue(E->getInit(0), LV, Info)) |
| return false; |
| APValue Val; |
| LV.moveInto(Val); |
| return Success(Val, E); |
| } |
| |
| bool Success = true; |
| |
| assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) && |
| "zero-initialized array shouldn't have any initialized elts"); |
| APValue Filler; |
| if (Result.isArray() && Result.hasArrayFiller()) |
| Filler = Result.getArrayFiller(); |
| |
| unsigned NumEltsToInit = E->getNumInits(); |
| unsigned NumElts = CAT->getSize().getZExtValue(); |
| const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : 0; |
| |
| // If the initializer might depend on the array index, run it for each |
| // array element. For now, just whitelist non-class value-initialization. |
| if (NumEltsToInit != NumElts && !isa<ImplicitValueInitExpr>(FillerExpr)) |
| NumEltsToInit = NumElts; |
| |
| Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts); |
| |
| // If the array was previously zero-initialized, preserve the |
| // zero-initialized values. |
| if (!Filler.isUninit()) { |
| for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I) |
| Result.getArrayInitializedElt(I) = Filler; |
| if (Result.hasArrayFiller()) |
| Result.getArrayFiller() = Filler; |
| } |
| |
| LValue Subobject = This; |
| Subobject.addArray(Info, E, CAT); |
| for (unsigned Index = 0; Index != NumEltsToInit; ++Index) { |
| const Expr *Init = |
| Index < E->getNumInits() ? E->getInit(Index) : FillerExpr; |
| if (!EvaluateInPlace(Result.getArrayInitializedElt(Index), |
| Info, Subobject, Init) || |
| !HandleLValueArrayAdjustment(Info, Init, Subobject, |
| CAT->getElementType(), 1)) { |
| if (!Info.keepEvaluatingAfterFailure()) |
| return false; |
| Success = false; |
| } |
| } |
| |
| if (!Result.hasArrayFiller()) |
| return Success; |
| |
| // If we get here, we have a trivial filler, which we can just evaluate |
| // once and splat over the rest of the array elements. |
| assert(FillerExpr && "no array filler for incomplete init list"); |
| return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, |
| FillerExpr) && Success; |
| } |
| |
| bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) { |
| return VisitCXXConstructExpr(E, This, &Result, E->getType()); |
| } |
| |
| bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E, |
| const LValue &Subobject, |
| APValue *Value, |
| QualType Type) { |
| bool HadZeroInit = !Value->isUninit(); |
| |
| if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) { |
| unsigned N = CAT->getSize().getZExtValue(); |
| |
| // Preserve the array filler if we had prior zero-initialization. |
| APValue Filler = |
| HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller() |
| : APValue(); |
| |
| *Value = APValue(APValue::UninitArray(), N, N); |
| |
| if (HadZeroInit) |
| for (unsigned I = 0; I != N; ++I) |
| Value->getArrayInitializedElt(I) = Filler; |
| |
| // Initialize the elements. |
| LValue ArrayElt = Subobject; |
| ArrayElt.addArray(Info, E, CAT); |
| for (unsigned I = 0; I != N; ++I) |
| if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I), |
| CAT->getElementType()) || |
| !HandleLValueArrayAdjustment(Info, E, ArrayElt, |
| CAT->getElementType(), 1)) |
| return false; |
| |
| return true; |
| } |
| |
| if (!Type->isRecordType()) |
| return Error(E); |
| |
| const CXXConstructorDecl *FD = E->getConstructor(); |
| |
| bool ZeroInit = E->requiresZeroInitialization(); |
| if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) { |
| if (HadZeroInit) |
| return true; |
| |
| if (ZeroInit) { |
| ImplicitValueInitExpr VIE(Type); |
| return EvaluateInPlace(*Value, Info, Subobject, &VIE); |
| } |
| |
| const CXXRecordDecl *RD = FD->getParent(); |
| if (RD->isUnion()) |
| *Value = APValue((FieldDecl*)0); |
| else |
| *Value = |
| APValue(APValue::UninitStruct(), RD->getNumBases(), |
| std::distance(RD->field_begin(), RD->field_end())); |
| return true; |
| } |
| |
| const FunctionDecl *Definition = 0; |
| FD->getBody(Definition); |
| |
| if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition)) |
| return false; |
| |
| if (ZeroInit && !HadZeroInit) { |
| ImplicitValueInitExpr VIE(Type); |
| if (!EvaluateInPlace(*Value, Info, Subobject, &VIE)) |
| return false; |
| } |
| |
| ArrayRef<const Expr *> Args(E->getArgs(), E->getNumArgs()); |
| return HandleConstructorCall(E->getExprLoc(), Subobject, Args, |
| cast<CXXConstructorDecl>(Definition), |
| Info, *Value); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Integer Evaluation |
| // |
| // As a GNU extension, we support casting pointers to sufficiently-wide integer |
| // types and back in constant folding. Integer values are thus represented |
| // either as an integer-valued APValue, or as an lvalue-valued APValue. |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class IntExprEvaluator |
| : public ExprEvaluatorBase<IntExprEvaluator, bool> { |
| APValue &Result; |
| public: |
| IntExprEvaluator(EvalInfo &info, APValue &result) |
| : ExprEvaluatorBaseTy(info), Result(result) {} |
| |
| bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) { |
| assert(E->getType()->isIntegralOrEnumerationType() && |
| "Invalid evaluation result."); |
| assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() && |
| "Invalid evaluation result."); |
| assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && |
| "Invalid evaluation result."); |
| Result = APValue(SI); |
| return true; |
| } |
| bool Success(const llvm::APSInt &SI, const Expr *E) { |
| return Success(SI, E, Result); |
| } |
| |
| bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) { |
| assert(E->getType()->isIntegralOrEnumerationType() && |
| "Invalid evaluation result."); |
| assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && |
| "Invalid evaluation result."); |
| Result = APValue(APSInt(I)); |
| Result.getInt().setIsUnsigned( |
| E->getType()->isUnsignedIntegerOrEnumerationType()); |
| return true; |
| } |
| bool Success(const llvm::APInt &I, const Expr *E) { |
| return Success(I, E, Result); |
| } |
| |
| bool Success(uint64_t Value, const Expr *E, APValue &Result) { |
| assert(E->getType()->isIntegralOrEnumerationType() && |
| "Invalid evaluation result."); |
| Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType())); |
| return true; |
| } |
| bool Success(uint64_t Value, const Expr *E) { |
| return Success(Value, E, Result); |
| } |
| |
| bool Success(CharUnits Size, const Expr *E) { |
| return Success(Size.getQuantity(), E); |
| } |
| |
| bool Success(const APValue &V, const Expr *E) { |
| if (V.isLValue() || V.isAddrLabelDiff()) { |
| Result = V; |
| return true; |
| } |
| return Success(V.getInt(), E); |
| } |
| |
| bool ZeroInitialization(const Expr *E) { return Success(0, E); } |
| |
| //===--------------------------------------------------------------------===// |
| // Visitor Methods |
| //===--------------------------------------------------------------------===// |
| |
| bool VisitIntegerLiteral(const IntegerLiteral *E) { |
| return Success(E->getValue(), E); |
| } |
| bool VisitCharacterLiteral(const CharacterLiteral *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| bool CheckReferencedDecl(const Expr *E, const Decl *D); |
| bool VisitDeclRefExpr(const DeclRefExpr *E) { |
| if (CheckReferencedDecl(E, E->getDecl())) |
| return true; |
| |
| return ExprEvaluatorBaseTy::VisitDeclRefExpr(E); |
| } |
| bool VisitMemberExpr(const MemberExpr *E) { |
| if (CheckReferencedDecl(E, E->getMemberDecl())) { |
| VisitIgnoredValue(E->getBase()); |
| return true; |
| } |
| |
| return ExprEvaluatorBaseTy::VisitMemberExpr(E); |
| } |
| |
| bool VisitCallExpr(const CallExpr *E); |
| bool VisitBinaryOperator(const BinaryOperator *E); |
| bool VisitOffsetOfExpr(const OffsetOfExpr *E); |
| bool VisitUnaryOperator(const UnaryOperator *E); |
| |
| bool VisitCastExpr(const CastExpr* E); |
| bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E); |
| |
| bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| // Note, GNU defines __null as an integer, not a pointer. |
| bool VisitGNUNullExpr(const GNUNullExpr *E) { |
| return ZeroInitialization(E); |
| } |
| |
| bool VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| bool VisitBinaryTypeTraitExpr(const BinaryTypeTraitExpr *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| bool VisitTypeTraitExpr(const TypeTraitExpr *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| bool VisitUnaryReal(const UnaryOperator *E); |
| bool VisitUnaryImag(const UnaryOperator *E); |
| |
| bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E); |
| bool VisitSizeOfPackExpr(const SizeOfPackExpr *E); |
| |
| private: |
| CharUnits GetAlignOfExpr(const Expr *E); |
| CharUnits GetAlignOfType(QualType T); |
| static QualType GetObjectType(APValue::LValueBase B); |
| bool TryEvaluateBuiltinObjectSize(const CallExpr *E); |
| // FIXME: Missing: array subscript of vector, member of vector |
| }; |
| } // end anonymous namespace |
| |
| /// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and |
| /// produce either the integer value or a pointer. |
| /// |
| /// GCC has a heinous extension which folds casts between pointer types and |
| /// pointer-sized integral types. We support this by allowing the evaluation of |
| /// an integer rvalue to produce a pointer (represented as an lvalue) instead. |
| /// Some simple arithmetic on such values is supported (they are treated much |
| /// like char*). |
| static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result, |
| EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType()); |
| return IntExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) { |
| APValue Val; |
| if (!EvaluateIntegerOrLValue(E, Val, Info)) |
| return false; |
| if (!Val.isInt()) { |
| // FIXME: It would be better to produce the diagnostic for casting |
| // a pointer to an integer. |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| return false; |
| } |
| Result = Val.getInt(); |
| return true; |
| } |
| |
| /// Check whether the given declaration can be directly converted to an integral |
| /// rvalue. If not, no diagnostic is produced; there are other things we can |
| /// try. |
| bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) { |
| // Enums are integer constant exprs. |
| if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) { |
| // Check for signedness/width mismatches between E type and ECD value. |
| bool SameSign = (ECD->getInitVal().isSigned() |
| == E->getType()->isSignedIntegerOrEnumerationType()); |
| bool SameWidth = (ECD->getInitVal().getBitWidth() |
| == Info.Ctx.getIntWidth(E->getType())); |
| if (SameSign && SameWidth) |
| return Success(ECD->getInitVal(), E); |
| else { |
| // Get rid of mismatch (otherwise Success assertions will fail) |
| // by computing a new value matching the type of E. |
| llvm::APSInt Val = ECD->getInitVal(); |
| if (!SameSign) |
| Val.setIsSigned(!ECD->getInitVal().isSigned()); |
| if (!SameWidth) |
| Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType())); |
| return Success(Val, E); |
| } |
| } |
| return false; |
| } |
| |
| /// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way |
| /// as GCC. |
| static int EvaluateBuiltinClassifyType(const CallExpr *E) { |
| // The following enum mimics the values returned by GCC. |
| // FIXME: Does GCC differ between lvalue and rvalue references here? |
| enum gcc_type_class { |
| no_type_class = -1, |
| void_type_class, integer_type_class, char_type_class, |
| enumeral_type_class, boolean_type_class, |
| pointer_type_class, reference_type_class, offset_type_class, |
| real_type_class, complex_type_class, |
| function_type_class, method_type_class, |
| record_type_class, union_type_class, |
| array_type_class, string_type_class, |
| lang_type_class |
| }; |
| |
| // If no argument was supplied, default to "no_type_class". This isn't |
| // ideal, however it is what gcc does. |
| if (E->getNumArgs() == 0) |
| return no_type_class; |
| |
| QualType ArgTy = E->getArg(0)->getType(); |
| if (ArgTy->isVoidType()) |
| return void_type_class; |
| else if (ArgTy->isEnumeralType()) |
| return enumeral_type_class; |
| else if (ArgTy->isBooleanType()) |
| return boolean_type_class; |
| else if (ArgTy->isCharType()) |
| return string_type_class; // gcc doesn't appear to use char_type_class |
| else if (ArgTy->isIntegerType()) |
| return integer_type_class; |
| else if (ArgTy->isPointerType()) |
| return pointer_type_class; |
| else if (ArgTy->isReferenceType()) |
| return reference_type_class; |
| else if (ArgTy->isRealType()) |
| return real_type_class; |
| else if (ArgTy->isComplexType()) |
| return complex_type_class; |
| else if (ArgTy->isFunctionType()) |
| return function_type_class; |
| else if (ArgTy->isStructureOrClassType()) |
| return record_type_class; |
| else if (ArgTy->isUnionType()) |
| return union_type_class; |
| else if (ArgTy->isArrayType()) |
| return array_type_class; |
| else if (ArgTy->isUnionType()) |
| return union_type_class; |
| else // FIXME: offset_type_class, method_type_class, & lang_type_class? |
| llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type"); |
| } |
| |
| /// EvaluateBuiltinConstantPForLValue - Determine the result of |
| /// __builtin_constant_p when applied to the given lvalue. |
| /// |
| /// An lvalue is only "constant" if it is a pointer or reference to the first |
| /// character of a string literal. |
| template<typename LValue> |
| static bool EvaluateBuiltinConstantPForLValue(const LValue &LV) { |
| const Expr *E = LV.getLValueBase().template dyn_cast<const Expr*>(); |
| return E && isa<StringLiteral>(E) && LV.getLValueOffset().isZero(); |
| } |
| |
| /// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to |
| /// GCC as we can manage. |
| static bool EvaluateBuiltinConstantP(ASTContext &Ctx, const Expr *Arg) { |
| QualType ArgType = Arg->getType(); |
| |
| // __builtin_constant_p always has one operand. The rules which gcc follows |
| // are not precisely documented, but are as follows: |
| // |
| // - If the operand is of integral, floating, complex or enumeration type, |
| // and can be folded to a known value of that type, it returns 1. |
| // - If the operand and can be folded to a pointer to the first character |
| // of a string literal (or such a pointer cast to an integral type), it |
| // returns 1. |
| // |
| // Otherwise, it returns 0. |
| // |
| // FIXME: GCC also intends to return 1 for literals of aggregate types, but |
| // its support for this does not currently work. |
| if (ArgType->isIntegralOrEnumerationType()) { |
| Expr::EvalResult Result; |
| if (!Arg->EvaluateAsRValue(Result, Ctx) || Result.HasSideEffects) |
| return false; |
| |
| APValue &V = Result.Val; |
| if (V.getKind() == APValue::Int) |
| return true; |
| |
| return EvaluateBuiltinConstantPForLValue(V); |
| } else if (ArgType->isFloatingType() || ArgType->isAnyComplexType()) { |
| return Arg->isEvaluatable(Ctx); |
| } else if (ArgType->isPointerType() || Arg->isGLValue()) { |
| LValue LV; |
| Expr::EvalStatus Status; |
| EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold); |
| if ((Arg->isGLValue() ? EvaluateLValue(Arg, LV, Info) |
| : EvaluatePointer(Arg, LV, Info)) && |
| !Status.HasSideEffects) |
| return EvaluateBuiltinConstantPForLValue(LV); |
| } |
| |
| // Anything else isn't considered to be sufficiently constant. |
| return false; |
| } |
| |
| /// Retrieves the "underlying object type" of the given expression, |
| /// as used by __builtin_object_size. |
| QualType IntExprEvaluator::GetObjectType(APValue::LValueBase B) { |
| if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { |
| if (const VarDecl *VD = dyn_cast<VarDecl>(D)) |
| return VD->getType(); |
| } else if (const Expr *E = B.get<const Expr*>()) { |
| if (isa<CompoundLiteralExpr>(E)) |
| return E->getType(); |
| } |
| |
| return QualType(); |
| } |
| |
| bool IntExprEvaluator::TryEvaluateBuiltinObjectSize(const CallExpr *E) { |
| LValue Base; |
| |
| { |
| // The operand of __builtin_object_size is never evaluated for side-effects. |
| // If there are any, but we can determine the pointed-to object anyway, then |
| // ignore the side-effects. |
| SpeculativeEvaluationRAII SpeculativeEval(Info); |
| if (!EvaluatePointer(E->getArg(0), Base, Info)) |
| return false; |
| } |
| |
| // If we can prove the base is null, lower to zero now. |
| if (!Base.getLValueBase()) return Success(0, E); |
| |
| QualType T = GetObjectType(Base.getLValueBase()); |
| if (T.isNull() || |
| T->isIncompleteType() || |
| T->isFunctionType() || |
| T->isVariablyModifiedType() || |
| T->isDependentType()) |
| return Error(E); |
| |
| CharUnits Size = Info.Ctx.getTypeSizeInChars(T); |
| CharUnits Offset = Base.getLValueOffset(); |
| |
| if (!Offset.isNegative() && Offset <= Size) |
| Size -= Offset; |
| else |
| Size = CharUnits::Zero(); |
| return Success(Size, E); |
| } |
| |
| bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) { |
| switch (unsigned BuiltinOp = E->isBuiltinCall()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitCallExpr(E); |
| |
| case Builtin::BI__builtin_object_size: { |
| if (TryEvaluateBuiltinObjectSize(E)) |
| return true; |
| |
| // If evaluating the argument has side-effects, we can't determine the size |
| // of the object, and so we lower it to unknown now. CodeGen relies on us to |
| // handle all cases where the expression has side-effects. |
| if (E->getArg(0)->HasSideEffects(Info.Ctx)) { |
| if (E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue() <= 1) |
| return Success(-1ULL, E); |
| return Success(0, E); |
| } |
| |
| // Expression had no side effects, but we couldn't statically determine the |
| // size of the referenced object. |
| return Error(E); |
| } |
| |
| case Builtin::BI__builtin_bswap16: |
| case Builtin::BI__builtin_bswap32: |
| case Builtin::BI__builtin_bswap64: { |
| APSInt Val; |
| if (!EvaluateInteger(E->getArg(0), Val, Info)) |
| return false; |
| |
| return Success(Val.byteSwap(), E); |
| } |
| |
| case Builtin::BI__builtin_classify_type: |
| return Success(EvaluateBuiltinClassifyType(E), E); |
| |
| // FIXME: BI__builtin_clrsb |
| // FIXME: BI__builtin_clrsbl |
| // FIXME: BI__builtin_clrsbll |
| |
| case Builtin::BI__builtin_clz: |
| case Builtin::BI__builtin_clzl: |
| case Builtin::BI__builtin_clzll: { |
| APSInt Val; |
| if (!EvaluateInteger(E->getArg(0), Val, Info)) |
| return false; |
| if (!Val) |
| return Error(E); |
| |
| return Success(Val.countLeadingZeros(), E); |
| } |
| |
| case Builtin::BI__builtin_constant_p: |
| return Success(EvaluateBuiltinConstantP(Info.Ctx, E->getArg(0)), E); |
| |
| case Builtin::BI__builtin_ctz: |
| case Builtin::BI__builtin_ctzl: |
| case Builtin::BI__builtin_ctzll: { |
| APSInt Val; |
| if (!EvaluateInteger(E->getArg(0), Val, Info)) |
| return false; |
| if (!Val) |
| return Error(E); |
| |
| return Success(Val.countTrailingZeros(), E); |
| } |
| |
| case Builtin::BI__builtin_eh_return_data_regno: { |
| int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue(); |
| Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand); |
| return Success(Operand, E); |
| } |
| |
| case Builtin::BI__builtin_expect: |
| return Visit(E->getArg(0)); |
| |
| case Builtin::BI__builtin_ffs: |
| case Builtin::BI__builtin_ffsl: |
| case Builtin::BI__builtin_ffsll: { |
| APSInt Val; |
| if (!EvaluateInteger(E->getArg(0), Val, Info)) |
| return false; |
| |
| unsigned N = Val.countTrailingZeros(); |
| return Success(N == Val.getBitWidth() ? 0 : N + 1, E); |
| } |
| |
| case Builtin::BI__builtin_fpclassify: { |
| APFloat Val(0.0); |
| if (!EvaluateFloat(E->getArg(5), Val, Info)) |
| return false; |
| unsigned Arg; |
| switch (Val.getCategory()) { |
| case APFloat::fcNaN: Arg = 0; break; |
| case APFloat::fcInfinity: Arg = 1; break; |
| case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break; |
| case APFloat::fcZero: Arg = 4; break; |
| } |
| return Visit(E->getArg(Arg)); |
| } |
| |
| case Builtin::BI__builtin_isinf_sign: { |
| APFloat Val(0.0); |
| return EvaluateFloat(E->getArg(0), Val, Info) && |
| Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E); |
| } |
| |
| case Builtin::BI__builtin_isinf: { |
| APFloat Val(0.0); |
| return EvaluateFloat(E->getArg(0), Val, Info) && |
| Success(Val.isInfinity() ? 1 : 0, E); |
| } |
| |
| case Builtin::BI__builtin_isfinite: { |
| APFloat Val(0.0); |
| return EvaluateFloat(E->getArg(0), Val, Info) && |
| Success(Val.isFinite() ? 1 : 0, E); |
| } |
| |
| case Builtin::BI__builtin_isnan: { |
| APFloat Val(0.0); |
| return EvaluateFloat(E->getArg(0), Val, Info) && |
| Success(Val.isNaN() ? 1 : 0, E); |
| } |
| |
| case Builtin::BI__builtin_isnormal: { |
| APFloat Val(0.0); |
| return EvaluateFloat(E->getArg(0), Val, Info) && |
| Success(Val.isNormal() ? 1 : 0, E); |
| } |
| |
| case Builtin::BI__builtin_parity: |
| case Builtin::BI__builtin_parityl: |
| case Builtin::BI__builtin_parityll: { |
| APSInt Val; |
| if (!EvaluateInteger(E->getArg(0), Val, Info)) |
| return false; |
| |
| return Success(Val.countPopulation() % 2, E); |
| } |
| |
| case Builtin::BI__builtin_popcount: |
| case Builtin::BI__builtin_popcountl: |
| case Builtin::BI__builtin_popcountll: { |
| APSInt Val; |
| if (!EvaluateInteger(E->getArg(0), Val, Info)) |
| return false; |
| |
| return Success(Val.countPopulation(), E); |
| } |
| |
| case Builtin::BIstrlen: |
| // A call to strlen is not a constant expression. |
| if (Info.getLangOpts().CPlusPlus11) |
| Info.CCEDiag(E, diag::note_constexpr_invalid_function) |
| << /*isConstexpr*/0 << /*isConstructor*/0 << "'strlen'"; |
| else |
| Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); |
| // Fall through. |
| case Builtin::BI__builtin_strlen: |
| // As an extension, we support strlen() and __builtin_strlen() as constant |
| // expressions when the argument is a string literal. |
| if (const StringLiteral *S |
| = dyn_cast<StringLiteral>(E->getArg(0)->IgnoreParenImpCasts())) { |
| // The string literal may have embedded null characters. Find the first |
| // one and truncate there. |
| StringRef Str = S->getString(); |
| StringRef::size_type Pos = Str.find(0); |
| if (Pos != StringRef::npos) |
| Str = Str.substr(0, Pos); |
| |
| return Success(Str.size(), E); |
| } |
| |
| return Error(E); |
| |
| case Builtin::BI__atomic_always_lock_free: |
| case Builtin::BI__atomic_is_lock_free: |
| case Builtin::BI__c11_atomic_is_lock_free: { |
| APSInt SizeVal; |
| if (!EvaluateInteger(E->getArg(0), SizeVal, Info)) |
| return false; |
| |
| // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power |
| // of two less than the maximum inline atomic width, we know it is |
| // lock-free. If the size isn't a power of two, or greater than the |
| // maximum alignment where we promote atomics, we know it is not lock-free |
| // (at least not in the sense of atomic_is_lock_free). Otherwise, |
| // the answer can only be determined at runtime; for example, 16-byte |
| // atomics have lock-free implementations on some, but not all, |
| // x86-64 processors. |
| |
| // Check power-of-two. |
| CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue()); |
| if (Size.isPowerOfTwo()) { |
| // Check against inlining width. |
| unsigned InlineWidthBits = |
| Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth(); |
| if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) { |
| if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free || |
| Size == CharUnits::One() || |
| E->getArg(1)->isNullPointerConstant(Info.Ctx, |
| Expr::NPC_NeverValueDependent)) |
| // OK, we will inline appropriately-aligned operations of this size, |
| // and _Atomic(T) is appropriately-aligned. |
| return Success(1, E); |
| |
| QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()-> |
| castAs<PointerType>()->getPointeeType(); |
| if (!PointeeType->isIncompleteType() && |
| Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) { |
| // OK, we will inline operations on this object. |
| return Success(1, E); |
| } |
| } |
| } |
| |
| return BuiltinOp == Builtin::BI__atomic_always_lock_free ? |
| Success(0, E) : Error(E); |
| } |
| } |
| } |
| |
| static bool HasSameBase(const LValue &A, const LValue &B) { |
| if (!A.getLValueBase()) |
| return !B.getLValueBase(); |
| if (!B.getLValueBase()) |
| return false; |
| |
| if (A.getLValueBase().getOpaqueValue() != |
| B.getLValueBase().getOpaqueValue()) { |
| const Decl *ADecl = GetLValueBaseDecl(A); |
| if (!ADecl) |
| return false; |
| const Decl *BDecl = GetLValueBaseDecl(B); |
| if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl()) |
| return false; |
| } |
| |
| return IsGlobalLValue(A.getLValueBase()) || |
| A.getLValueCallIndex() == B.getLValueCallIndex(); |
| } |
| |
| namespace { |
| |
| /// \brief Data recursive integer evaluator of certain binary operators. |
| /// |
| /// We use a data recursive algorithm for binary operators so that we are able |
| /// to handle extreme cases of chained binary operators without causing stack |
| /// overflow. |
| class DataRecursiveIntBinOpEvaluator { |
| struct EvalResult { |
| APValue Val; |
| bool Failed; |
| |
| EvalResult() : Failed(false) { } |
| |
| void swap(EvalResult &RHS) { |
| Val.swap(RHS.Val); |
| Failed = RHS.Failed; |
| RHS.Failed = false; |
| } |
| }; |
| |
| struct Job { |
| const Expr *E; |
| EvalResult LHSResult; // meaningful only for binary operator expression. |
| enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind; |
| |
| Job() : StoredInfo(0) { } |
| void startSpeculativeEval(EvalInfo &Info) { |
| OldEvalStatus = Info.EvalStatus; |
| Info.EvalStatus.Diag = 0; |
| StoredInfo = &Info; |
| } |
| ~Job() { |
| if (StoredInfo) { |
| StoredInfo->EvalStatus = OldEvalStatus; |
| } |
| } |
| private: |
| EvalInfo *StoredInfo; // non-null if status changed. |
| Expr::EvalStatus OldEvalStatus; |
| }; |
| |
| SmallVector<Job, 16> Queue; |
| |
| IntExprEvaluator &IntEval; |
| EvalInfo &Info; |
| APValue &FinalResult; |
| |
| public: |
| DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result) |
| : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { } |
| |
| /// \brief True if \param E is a binary operator that we are going to handle |
| /// data recursively. |
| /// We handle binary operators that are comma, logical, or that have operands |
| /// with integral or enumeration type. |
| static bool shouldEnqueue(const BinaryOperator *E) { |
| return E->getOpcode() == BO_Comma || |
| E->isLogicalOp() || |
| (E->getLHS()->getType()->isIntegralOrEnumerationType() && |
| E->getRHS()->getType()->isIntegralOrEnumerationType()); |
| } |
| |
| bool Traverse(const BinaryOperator *E) { |
| enqueue(E); |
| EvalResult PrevResult; |
| while (!Queue.empty()) |
| process(PrevResult); |
| |
| if (PrevResult.Failed) return false; |
| |
| FinalResult.swap(PrevResult.Val); |
| return true; |
| } |
| |
| private: |
| bool Success(uint64_t Value, const Expr *E, APValue &Result) { |
| return IntEval.Success(Value, E, Result); |
| } |
| bool Success(const APSInt &Value, const Expr *E, APValue &Result) { |
| return IntEval.Success(Value, E, Result); |
| } |
| bool Error(const Expr *E) { |
| return IntEval.Error(E); |
| } |
| bool Error(const Expr *E, diag::kind D) { |
| return IntEval.Error(E, D); |
| } |
| |
| OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) { |
| return Info.CCEDiag(E, D); |
| } |
| |
| // \brief Returns true if visiting the RHS is necessary, false otherwise. |
| bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E, |
| bool &SuppressRHSDiags); |
| |
| bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult, |
| const BinaryOperator *E, APValue &Result); |
| |
| void EvaluateExpr(const Expr *E, EvalResult &Result) { |
| Result.Failed = !Evaluate(Result.Val, Info, E); |
| if (Result.Failed) |
| Result.Val = APValue(); |
| } |
| |
| void process(EvalResult &Result); |
| |
| void enqueue(const Expr *E) { |
| E = E->IgnoreParens(); |
| Queue.resize(Queue.size()+1); |
| Queue.back().E = E; |
| Queue.back().Kind = Job::AnyExprKind; |
| } |
| }; |
| |
| } |
| |
| bool DataRecursiveIntBinOpEvaluator:: |
| VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E, |
| bool &SuppressRHSDiags) { |
| if (E->getOpcode() == BO_Comma) { |
| // Ignore LHS but note if we could not evaluate it. |
| if (LHSResult.Failed) |
| return Info.noteSideEffect(); |
| return true; |
| } |
| |
| if (E->isLogicalOp()) { |
| bool LHSAsBool; |
| if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) { |
| // We were able to evaluate the LHS, see if we can get away with not |
| // evaluating the RHS: 0 && X -> 0, 1 || X -> 1 |
| if (LHSAsBool == (E->getOpcode() == BO_LOr)) { |
| Success(LHSAsBool, E, LHSResult.Val); |
| return false; // Ignore RHS |
| } |
| } else { |
| LHSResult.Failed = true; |
| |
| // Since we weren't able to evaluate the left hand side, it |
| // must have had side effects. |
| if (!Info.noteSideEffect()) |
| return false; |
| |
| // We can't evaluate the LHS; however, sometimes the result |
| // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. |
| // Don't ignore RHS and suppress diagnostics from this arm. |
| SuppressRHSDiags = true; |
| } |
| |
| return true; |
| } |
| |
| assert(E->getLHS()->getType()->isIntegralOrEnumerationType() && |
| E->getRHS()->getType()->isIntegralOrEnumerationType()); |
| |
| if (LHSResult.Failed && !Info.keepEvaluatingAfterFailure()) |
| return false; // Ignore RHS; |
| |
| return true; |
| } |
| |
| bool DataRecursiveIntBinOpEvaluator:: |
| VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult, |
| const BinaryOperator *E, APValue &Result) { |
| if (E->getOpcode() == BO_Comma) { |
| if (RHSResult.Failed) |
| return false; |
| Result = RHSResult.Val; |
| return true; |
| } |
| |
| if (E->isLogicalOp()) { |
| bool lhsResult, rhsResult; |
| bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult); |
| bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult); |
| |
| if (LHSIsOK) { |
| if (RHSIsOK) { |
| if (E->getOpcode() == BO_LOr) |
| return Success(lhsResult || rhsResult, E, Result); |
| else |
| return Success(lhsResult && rhsResult, E, Result); |
| } |
| } else { |
| if (RHSIsOK) { |
| // We can't evaluate the LHS; however, sometimes the result |
| // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. |
| if (rhsResult == (E->getOpcode() == BO_LOr)) |
| return Success(rhsResult, E, Result); |
| } |
| } |
| |
| return false; |
| } |
| |
| assert(E->getLHS()->getType()->isIntegralOrEnumerationType() && |
| E->getRHS()->getType()->isIntegralOrEnumerationType()); |
| |
| if (LHSResult.Failed || RHSResult.Failed) |
| return false; |
| |
| const APValue &LHSVal = LHSResult.Val; |
| const APValue &RHSVal = RHSResult.Val; |
| |
| // Handle cases like (unsigned long)&a + 4. |
| if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) { |
| Result = LHSVal; |
| CharUnits AdditionalOffset = CharUnits::fromQuantity( |
| RHSVal.getInt().getZExtValue()); |
| if (E->getOpcode() == BO_Add) |
| Result.getLValueOffset() += AdditionalOffset; |
| else |
| Result.getLValueOffset() -= AdditionalOffset; |
| return true; |
| } |
| |
| // Handle cases like 4 + (unsigned long)&a |
| if (E->getOpcode() == BO_Add && |
| RHSVal.isLValue() && LHSVal.isInt()) { |
| Result = RHSVal; |
| Result.getLValueOffset() += CharUnits::fromQuantity( |
| LHSVal.getInt().getZExtValue()); |
| return true; |
| } |
| |
| if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) { |
| // Handle (intptr_t)&&A - (intptr_t)&&B. |
| if (!LHSVal.getLValueOffset().isZero() || |
| !RHSVal.getLValueOffset().isZero()) |
| return false; |
| const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>(); |
| const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>(); |
| if (!LHSExpr || !RHSExpr) |
| return false; |
| const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr); |
| const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr); |
| if (!LHSAddrExpr || !RHSAddrExpr) |
| return false; |
| // Make sure both labels come from the same function. |
| if (LHSAddrExpr->getLabel()->getDeclContext() != |
| RHSAddrExpr->getLabel()->getDeclContext()) |
| return false; |
| Result = APValue(LHSAddrExpr, RHSAddrExpr); |
| return true; |
| } |
| |
| // All the remaining cases expect both operands to be an integer |
| if (!LHSVal.isInt() || !RHSVal.isInt()) |
| return Error(E); |
| |
| // Set up the width and signedness manually, in case it can't be deduced |
| // from the operation we're performing. |
| // FIXME: Don't do this in the cases where we can deduce it. |
| APSInt Value(Info.Ctx.getIntWidth(E->getType()), |
| E->getType()->isUnsignedIntegerOrEnumerationType()); |
| if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(), |
| RHSVal.getInt(), Value)) |
| return false; |
| return Success(Value, E, Result); |
| } |
| |
| void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) { |
| Job &job = Queue.back(); |
| |
| switch (job.Kind) { |
| case Job::AnyExprKind: { |
| if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) { |
| if (shouldEnqueue(Bop)) { |
| job.Kind = Job::BinOpKind; |
| enqueue(Bop->getLHS()); |
| return; |
| } |
| } |
| |
| EvaluateExpr(job.E, Result); |
| Queue.pop_back(); |
| return; |
| } |
| |
| case Job::BinOpKind: { |
| const BinaryOperator *Bop = cast<BinaryOperator>(job.E); |
| bool SuppressRHSDiags = false; |
| if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) { |
| Queue.pop_back(); |
| return; |
| } |
| if (SuppressRHSDiags) |
| job.startSpeculativeEval(Info); |
| job.LHSResult.swap(Result); |
| job.Kind = Job::BinOpVisitedLHSKind; |
| enqueue(Bop->getRHS()); |
| return; |
| } |
| |
| case Job::BinOpVisitedLHSKind: { |
| const BinaryOperator *Bop = cast<BinaryOperator>(job.E); |
| EvalResult RHS; |
| RHS.swap(Result); |
| Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val); |
| Queue.pop_back(); |
| return; |
| } |
| } |
| |
| llvm_unreachable("Invalid Job::Kind!"); |
| } |
| |
| bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { |
| if (E->isAssignmentOp()) |
| return Error(E); |
| |
| if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E)) |
| return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E); |
| |
| QualType LHSTy = E->getLHS()->getType(); |
| QualType RHSTy = E->getRHS()->getType(); |
| |
| if (LHSTy->isAnyComplexType()) { |
| assert(RHSTy->isAnyComplexType() && "Invalid comparison"); |
| ComplexValue LHS, RHS; |
| |
| bool LHSOK = EvaluateComplex(E->getLHS(), LHS, Info); |
| if (!LHSOK && !Info.keepEvaluatingAfterFailure()) |
| return false; |
| |
| if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK) |
| return false; |
| |
| if (LHS.isComplexFloat()) { |
| APFloat::cmpResult CR_r = |
| LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal()); |
| APFloat::cmpResult CR_i = |
| LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag()); |
| |
| if (E->getOpcode() == BO_EQ) |
| return Success((CR_r == APFloat::cmpEqual && |
| CR_i == APFloat::cmpEqual), E); |
| else { |
| assert(E->getOpcode() == BO_NE && |
| "Invalid complex comparison."); |
| return Success(((CR_r == APFloat::cmpGreaterThan || |
| CR_r == APFloat::cmpLessThan || |
| CR_r == APFloat::cmpUnordered) || |
| (CR_i == APFloat::cmpGreaterThan || |
| CR_i == APFloat::cmpLessThan || |
| CR_i == APFloat::cmpUnordered)), E); |
| } |
| } else { |
| if (E->getOpcode() == BO_EQ) |
| return Success((LHS.getComplexIntReal() == RHS.getComplexIntReal() && |
| LHS.getComplexIntImag() == RHS.getComplexIntImag()), E); |
| else { |
| assert(E->getOpcode() == BO_NE && |
| "Invalid compex comparison."); |
| return Success((LHS.getComplexIntReal() != RHS.getComplexIntReal() || |
| LHS.getComplexIntImag() != RHS.getComplexIntImag()), E); |
| } |
| } |
| } |
| |
| if (LHSTy->isRealFloatingType() && |
| RHSTy->isRealFloatingType()) { |
| APFloat RHS(0.0), LHS(0.0); |
| |
| bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info); |
| if (!LHSOK && !Info.keepEvaluatingAfterFailure()) |
| return false; |
| |
| if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK) |
| return false; |
| |
| APFloat::cmpResult CR = LHS.compare(RHS); |
| |
| switch (E->getOpcode()) { |
| default: |
| llvm_unreachable("Invalid binary operator!"); |
| case BO_LT: |
| return Success(CR == APFloat::cmpLessThan, E); |
| case BO_GT: |
| return Success(CR == APFloat::cmpGreaterThan, E); |
| case BO_LE: |
| return Success(CR == APFloat::cmpLessThan || CR == APFloat::cmpEqual, E); |
| case BO_GE: |
| return Success(CR == APFloat::cmpGreaterThan || CR == APFloat::cmpEqual, |
| E); |
| case BO_EQ: |
| return Success(CR == APFloat::cmpEqual, E); |
| case BO_NE: |
| return Success(CR == APFloat::cmpGreaterThan |
| || CR == APFloat::cmpLessThan |
| || CR == APFloat::cmpUnordered, E); |
| } |
| } |
| |
| if (LHSTy->isPointerType() && RHSTy->isPointerType()) { |
| if (E->getOpcode() == BO_Sub || E->isComparisonOp()) { |
| LValue LHSValue, RHSValue; |
| |
| bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info); |
| if (!LHSOK && Info.keepEvaluatingAfterFailure()) |
| return false; |
| |
| if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK) |
| return false; |
| |
| // Reject differing bases from the normal codepath; we special-case |
| // comparisons to null. |
| if (!HasSameBase(LHSValue, RHSValue)) { |
| if (E->getOpcode() == BO_Sub) { |
| // Handle &&A - &&B. |
| if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero()) |
| return false; |
| const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr*>(); |
| const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr*>(); |
| if (!LHSExpr || !RHSExpr) |
| return false; |
| const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr); |
| const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr); |
| if (!LHSAddrExpr || !RHSAddrExpr) |
| return false; |
| // Make sure both labels come from the same function. |
| if (LHSAddrExpr->getLabel()->getDeclContext() != |
| RHSAddrExpr->getLabel()->getDeclContext()) |
| return false; |
| Result = APValue(LHSAddrExpr, RHSAddrExpr); |
| return true; |
| } |
| // Inequalities and subtractions between unrelated pointers have |
| // unspecified or undefined behavior. |
| if (!E->isEqualityOp()) |
| return Error(E); |
| // A constant address may compare equal to the address of a symbol. |
| // The one exception is that address of an object cannot compare equal |
| // to a null pointer constant. |
| if ((!LHSValue.Base && !LHSValue.Offset.isZero()) || |
| (!RHSValue.Base && !RHSValue.Offset.isZero())) |
| return Error(E); |
| // It's implementation-defined whether distinct literals will have |
| // distinct addresses. In clang, the result of such a comparison is |
| // unspecified, so it is not a constant expression. However, we do know |
| // that the address of a literal will be non-null. |
| if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) && |
| LHSValue.Base && RHSValue.Base) |
| return Error(E); |
| // We can't tell whether weak symbols will end up pointing to the same |
| // object. |
| if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue)) |
| return Error(E); |
| // Pointers with different bases cannot represent the same object. |
| // (Note that clang defaults to -fmerge-all-constants, which can |
| // lead to inconsistent results for comparisons involving the address |
| // of a constant; this generally doesn't matter in practice.) |
| return Success(E->getOpcode() == BO_NE, E); |
| } |
| |
| const CharUnits &LHSOffset = LHSValue.getLValueOffset(); |
| const CharUnits &RHSOffset = RHSValue.getLValueOffset(); |
| |
| SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator(); |
| SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator(); |
| |
| if (E->getOpcode() == BO_Sub) { |
| // C++11 [expr.add]p6: |
| // Unless both pointers point to elements of the same array object, or |
| // one past the last element of the array object, the behavior is |
| // undefined. |
| if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && |
| !AreElementsOfSameArray(getType(LHSValue.Base), |
| LHSDesignator, RHSDesignator)) |
| CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array); |
| |
| QualType Type = E->getLHS()->getType(); |
| QualType ElementType = Type->getAs<PointerType>()->getPointeeType(); |
| |
| CharUnits ElementSize; |
| if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize)) |
| return false; |
| |
| // As an extension, a type may have zero size (empty struct or union in |
| // C, array of zero length). Pointer subtraction in such cases has |
| // undefined behavior, so is not constant. |
| if (ElementSize.isZero()) { |
| Info.Diag(E, diag::note_constexpr_pointer_subtraction_zero_size) |
| << ElementType; |
| return false; |
| } |
| |
| // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime, |
| // and produce incorrect results when it overflows. Such behavior |
| // appears to be non-conforming, but is common, so perhaps we should |
| // assume the standard intended for such cases to be undefined behavior |
| // and check for them. |
| |
| // Compute (LHSOffset - RHSOffset) / Size carefully, checking for |
| // overflow in the final conversion to ptrdiff_t. |
| APSInt LHS( |
| llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false); |
| APSInt RHS( |
| llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false); |
| APSInt ElemSize( |
| llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true), false); |
| APSInt TrueResult = (LHS - RHS) / ElemSize; |
| APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType())); |
| |
| if (Result.extend(65) != TrueResult) |
| HandleOverflow(Info, E, TrueResult, E->getType()); |
| return Success(Result, E); |
| } |
| |
| // C++11 [expr.rel]p3: |
| // Pointers to void (after pointer conversions) can be compared, with a |
| // result defined as follows: If both pointers represent the same |
| // address or are both the null pointer value, the result is true if the |
| // operator is <= or >= and false otherwise; otherwise the result is |
| // unspecified. |
| // We interpret this as applying to pointers to *cv* void. |
| if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && |
| E->isRelationalOp()) |
| CCEDiag(E, diag::note_constexpr_void_comparison); |
| |
| // C++11 [expr.rel]p2: |
| // - If two pointers point to non-static data members of the same object, |
| // or to subobjects or array elements fo such members, recursively, the |
| // pointer to the later declared member compares greater provided the |
| // two members have the same access control and provided their class is |
| // not a union. |
| // [...] |
| // - Otherwise pointer comparisons are unspecified. |
| if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && |
| E->isRelationalOp()) { |
| bool WasArrayIndex; |
| unsigned Mismatch = |
| FindDesignatorMismatch(getType(LHSValue.Base), LHSDesignator, |
| RHSDesignator, WasArrayIndex); |
| // At the point where the designators diverge, the comparison has a |
| // specified value if: |
| // - we are comparing array indices |
| // - we are comparing fields of a union, or fields with the same access |
| // Otherwise, the result is unspecified and thus the comparison is not a |
| // constant expression. |
| if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() && |
| Mismatch < RHSDesignator.Entries.size()) { |
| const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]); |
| const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]); |
| if (!LF && !RF) |
| CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes); |
| else if (!LF) |
| CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field) |
| << getAsBaseClass(LHSDesignator.Entries[Mismatch]) |
| << RF->getParent() << RF; |
| else if (!RF) |
| CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field) |
| << getAsBaseClass(RHSDesignator.Entries[Mismatch]) |
| << LF->getParent() << LF; |
| else if (!LF->getParent()->isUnion() && |
| LF->getAccess() != RF->getAccess()) |
| CCEDiag(E, diag::note_constexpr_pointer_comparison_differing_access) |
| << LF << LF->getAccess() << RF << RF->getAccess() |
| << LF->getParent(); |
| } |
| } |
| |
| // The comparison here must be unsigned, and performed with the same |
| // width as the pointer. |
| unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy); |
| uint64_t CompareLHS = LHSOffset.getQuantity(); |
| uint64_t CompareRHS = RHSOffset.getQuantity(); |
| assert(PtrSize <= 64 && "Unexpected pointer width"); |
| uint64_t Mask = ~0ULL >> (64 - PtrSize); |
| CompareLHS &= Mask; |
| CompareRHS &= Mask; |
| |
| // If there is a base and this is a relational operator, we can only |
| // compare pointers within the object in question; otherwise, the result |
| // depends on where the object is located in memory. |
| if (!LHSValue.Base.isNull() && E->isRelationalOp()) { |
| QualType BaseTy = getType(LHSValue.Base); |
| if (BaseTy->isIncompleteType()) |
| return Error(E); |
| CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy); |
| uint64_t OffsetLimit = Size.getQuantity(); |
| if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit) |
| return Error(E); |
| } |
| |
| switch (E->getOpcode()) { |
| default: llvm_unreachable("missing comparison operator"); |
| case BO_LT: return Success(CompareLHS < CompareRHS, E); |
| case BO_GT: return Success(CompareLHS > CompareRHS, E); |
| case BO_LE: return Success(CompareLHS <= CompareRHS, E); |
| case BO_GE: return Success(CompareLHS >= CompareRHS, E); |
| case BO_EQ: return Success(CompareLHS == CompareRHS, E); |
| case BO_NE: return Success(CompareLHS != CompareRHS, E); |
| } |
| } |
| } |
| |
| if (LHSTy->isMemberPointerType()) { |
| assert(E->isEqualityOp() && "unexpected member pointer operation"); |
| assert(RHSTy->isMemberPointerType() && "invalid comparison"); |
| |
| MemberPtr LHSValue, RHSValue; |
| |
| bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info); |
| if (!LHSOK && Info.keepEvaluatingAfterFailure()) |
| return false; |
| |
| if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK) |
| return false; |
| |
| // C++11 [expr.eq]p2: |
| // If both operands are null, they compare equal. Otherwise if only one is |
| // null, they compare unequal. |
| if (!LHSValue.getDecl() || !RHSValue.getDecl()) { |
| bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl(); |
| return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E); |
| } |
| |
| // Otherwise if either is a pointer to a virtual member function, the |
| // result is unspecified. |
| if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl())) |
| if (MD->isVirtual()) |
| CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD; |
| if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl())) |
| if (MD->isVirtual()) |
| CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD; |
| |
| // Otherwise they compare equal if and only if they would refer to the |
| // same member of the same most derived object or the same subobject if |
| // they were dereferenced with a hypothetical object of the associated |
| // class type. |
| bool Equal = LHSValue == RHSValue; |
| return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E); |
| } |
| |
| if (LHSTy->isNullPtrType()) { |
| assert(E->isComparisonOp() && "unexpected nullptr operation"); |
| assert(RHSTy->isNullPtrType() && "missing pointer conversion"); |
| // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t |
| // are compared, the result is true of the operator is <=, >= or ==, and |
| // false otherwise. |
| BinaryOperator::Opcode Opcode = E->getOpcode(); |
| return Success(Opcode == BO_EQ || Opcode == BO_LE || Opcode == BO_GE, E); |
| } |
| |
| assert((!LHSTy->isIntegralOrEnumerationType() || |
| !RHSTy->isIntegralOrEnumerationType()) && |
| "DataRecursiveIntBinOpEvaluator should have handled integral types"); |
| // We can't continue from here for non-integral types. |
| return ExprEvaluatorBaseTy::VisitBinaryOperator(E); |
| } |
| |
| CharUnits IntExprEvaluator::GetAlignOfType(QualType T) { |
| // C++ [expr.alignof]p3: "When alignof is applied to a reference type, the |
| // result shall be the alignment of the referenced type." |
| if (const ReferenceType *Ref = T->getAs<ReferenceType>()) |
| T = Ref->getPointeeType(); |
| |
| // __alignof is defined to return the preferred alignment. |
| return Info.Ctx.toCharUnitsFromBits( |
| Info.Ctx.getPreferredTypeAlign(T.getTypePtr())); |
| } |
| |
| CharUnits IntExprEvaluator::GetAlignOfExpr(const Expr *E) { |
| E = E->IgnoreParens(); |
| |
| // The kinds of expressions that we have special-case logic here for |
| // should be kept up to date with the special checks for those |
| // expressions in Sema. |
| |
| // alignof decl is always accepted, even if it doesn't make sense: we default |
| // to 1 in those cases. |
| if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) |
| return Info.Ctx.getDeclAlign(DRE->getDecl(), |
| /*RefAsPointee*/true); |
| |
| if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) |
| return Info.Ctx.getDeclAlign(ME->getMemberDecl(), |
| /*RefAsPointee*/true); |
| |
| return GetAlignOfType(E->getType()); |
| } |
| |
| |
| /// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with |
| /// a result as the expression's type. |
| bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr( |
| const UnaryExprOrTypeTraitExpr *E) { |
| switch(E->getKind()) { |
| case UETT_AlignOf: { |
| if (E->isArgumentType()) |
| return Success(GetAlignOfType(E->getArgumentType()), E); |
| else |
| return Success(GetAlignOfExpr(E->getArgumentExpr()), E); |
| } |
| |
| case UETT_VecStep: { |
| QualType Ty = E->getTypeOfArgument(); |
| |
| if (Ty->isVectorType()) { |
| unsigned n = Ty->castAs<VectorType>()->getNumElements(); |
| |
| // The vec_step built-in functions that take a 3-component |
| // vector return 4. (OpenCL 1.1 spec 6.11.12) |
| if (n == 3) |
| n = 4; |
| |
| return Success(n, E); |
| } else |
| return Success(1, E); |
| } |
| |
| case UETT_SizeOf: { |
| QualType SrcTy = E->getTypeOfArgument(); |
| // C++ [expr.sizeof]p2: "When applied to a reference or a reference type, |
| // the result is the size of the referenced type." |
| if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>()) |
| SrcTy = Ref->getPointeeType(); |
| |
| CharUnits Sizeof; |
| if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof)) |
| return false; |
| return Success(Sizeof, E); |
| } |
| } |
| |
| llvm_unreachable("unknown expr/type trait"); |
| } |
| |
| bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) { |
| CharUnits Result; |
| unsigned n = OOE->getNumComponents(); |
| if (n == 0) |
| return Error(OOE); |
| QualType CurrentType = OOE->getTypeSourceInfo()->getType(); |
| for (unsigned i = 0; i != n; ++i) { |
| OffsetOfExpr::OffsetOfNode ON = OOE->getComponent(i); |
| switch (ON.getKind()) { |
| case OffsetOfExpr::OffsetOfNode::Array: { |
| const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex()); |
| APSInt IdxResult; |
| if (!EvaluateInteger(Idx, IdxResult, Info)) |
| return false; |
| const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType); |
| if (!AT) |
| return Error(OOE); |
| CurrentType = AT->getElementType(); |
| CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType); |
| Result += IdxResult.getSExtValue() * ElementSize; |
| break; |
| } |
| |
| case OffsetOfExpr::OffsetOfNode::Field: { |
| FieldDecl *MemberDecl = ON.getField(); |
| const RecordType *RT = CurrentType->getAs<RecordType>(); |
| if (!RT) |
| return Error(OOE); |
| RecordDecl *RD = RT->getDecl(); |
| if (RD->isInvalidDecl()) return false; |
| const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); |
| unsigned i = MemberDecl->getFieldIndex(); |
| assert(i < RL.getFieldCount() && "offsetof field in wrong type"); |
| Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i)); |
| CurrentType = MemberDecl->getType().getNonReferenceType(); |
| break; |
| } |
| |
| case OffsetOfExpr::OffsetOfNode::Identifier: |
| llvm_unreachable("dependent __builtin_offsetof"); |
| |
| case OffsetOfExpr::OffsetOfNode::Base: { |
| CXXBaseSpecifier *BaseSpec = ON.getBase(); |
| if (BaseSpec->isVirtual()) |
| return Error(OOE); |
| |
| // Find the layout of the class whose base we are looking into. |
| const RecordType *RT = CurrentType->getAs<RecordType>(); |
| if (!RT) |
| return Error(OOE); |
| RecordDecl *RD = RT->getDecl(); |
| if (RD->isInvalidDecl()) return false; |
| const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); |
| |
| // Find the base class itself. |
| CurrentType = BaseSpec->getType(); |
| const RecordType *BaseRT = CurrentType->getAs<RecordType>(); |
| if (!BaseRT) |
| return Error(OOE); |
| |
| // Add the offset to the base. |
| Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl())); |
| break; |
| } |
| } |
| } |
| return Success(Result, OOE); |
| } |
| |
| bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { |
| switch (E->getOpcode()) { |
| default: |
| // Address, indirect, pre/post inc/dec, etc are not valid constant exprs. |
| // See C99 6.6p3. |
| return Error(E); |
| case UO_Extension: |
| // FIXME: Should extension allow i-c-e extension expressions in its scope? |
| // If so, we could clear the diagnostic ID. |
| return Visit(E->getSubExpr()); |
| case UO_Plus: |
| // The result is just the value. |
| return Visit(E->getSubExpr()); |
| case UO_Minus: { |
| if (!Visit(E->getSubExpr())) |
| return false; |
| if (!Result.isInt()) return Error(E); |
| const APSInt &Value = Result.getInt(); |
| if (Value.isSigned() && Value.isMinSignedValue()) |
| HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1), |
| E->getType()); |
| return Success(-Value, E); |
| } |
| case UO_Not: { |
| if (!Visit(E->getSubExpr())) |
| return false; |
| if (!Result.isInt()) return Error(E); |
| return Success(~Result.getInt(), E); |
| } |
| case UO_LNot: { |
| bool bres; |
| if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info)) |
| return false; |
| return Success(!bres, E); |
| } |
| } |
| } |
| |
| /// HandleCast - This is used to evaluate implicit or explicit casts where the |
| /// result type is integer. |
| bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) { |
| const Expr *SubExpr = E->getSubExpr(); |
| QualType DestType = E->getType(); |
| QualType SrcType = SubExpr->getType(); |
| |
| switch (E->getCastKind()) { |
| case CK_BaseToDerived: |
| case CK_DerivedToBase: |
| case CK_UncheckedDerivedToBase: |
| case CK_Dynamic: |
| case CK_ToUnion: |
| case CK_ArrayToPointerDecay: |
| case CK_FunctionToPointerDecay: |
| case CK_NullToPointer: |
| case CK_NullToMemberPointer: |
| case CK_BaseToDerivedMemberPointer: |
| case CK_DerivedToBaseMemberPointer: |
| case CK_ReinterpretMemberPointer: |
| case CK_ConstructorConversion: |
| case CK_IntegralToPointer: |
| case CK_ToVoid: |
| case CK_VectorSplat: |
| case CK_IntegralToFloating: |
| case CK_FloatingCast: |
| case CK_CPointerToObjCPointerCast: |
| case CK_BlockPointerToObjCPointerCast: |
| case CK_AnyPointerToBlockPointerCast: |
| case CK_ObjCObjectLValueCast: |
| case CK_FloatingRealToComplex: |
| case CK_FloatingComplexToReal: |
| case CK_FloatingComplexCast: |
| case CK_FloatingComplexToIntegralComplex: |
| case CK_IntegralRealToComplex: |
| case CK_IntegralComplexCast: |
| case CK_IntegralComplexToFloatingComplex: |
| case CK_BuiltinFnToFnPtr: |
| case CK_ZeroToOCLEvent: |
| case CK_NonAtomicToAtomic: |
| llvm_unreachable("invalid cast kind for integral value"); |
| |
| case CK_BitCast: |
| case CK_Dependent: |
| case CK_LValueBitCast: |
| case CK_ARCProduceObject: |
| case CK_ARCConsumeObject: |
| case CK_ARCReclaimReturnedObject: |
| case CK_ARCExtendBlockObject: |
| case CK_CopyAndAutoreleaseBlockObject: |
| return Error(E); |
| |
| case CK_UserDefinedConversion: |
| case CK_LValueToRValue: |
| case CK_AtomicToNonAtomic: |
| case CK_NoOp: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| |
| case CK_MemberPointerToBoolean: |
| case CK_PointerToBoolean: |
| case CK_IntegralToBoolean: |
| case CK_FloatingToBoolean: |
| case CK_FloatingComplexToBoolean: |
| case CK_IntegralComplexToBoolean: { |
| bool BoolResult; |
| if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info)) |
| return false; |
| return Success(BoolResult, E); |
| } |
| |
| case CK_IntegralCast: { |
| if (!Visit(SubExpr)) |
| return false; |
| |
| if (!Result.isInt()) { |
| // Allow casts of address-of-label differences if they are no-ops |
| // or narrowing. (The narrowing case isn't actually guaranteed to |
| // be constant-evaluatable except in some narrow cases which are hard |
| // to detect here. We let it through on the assumption the user knows |
| // what they are doing.) |
| if (Result.isAddrLabelDiff()) |
| return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType); |
| // Only allow casts of lvalues if they are lossless. |
| return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType); |
| } |
| |
| return Success(HandleIntToIntCast(Info, E, DestType, SrcType, |
| Result.getInt()), E); |
| } |
| |
| case CK_PointerToIntegral: { |
| CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; |
| |
| LValue LV; |
| if (!EvaluatePointer(SubExpr, LV, Info)) |
| return false; |
| |
| if (LV.getLValueBase()) { |
| // Only allow based lvalue casts if they are lossless. |
| // FIXME: Allow a larger integer size than the pointer size, and allow |
| // narrowing back down to pointer width in subsequent integral casts. |
| // FIXME: Check integer type's active bits, not its type size. |
| if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType)) |
| return Error(E); |
| |
| LV.Designator.setInvalid(); |
| LV.moveInto(Result); |
| return true; |
| } |
| |
| APSInt AsInt = Info.Ctx.MakeIntValue(LV.getLValueOffset().getQuantity(), |
| SrcType); |
| return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E); |
| } |
| |
| case CK_IntegralComplexToReal: { |
| ComplexValue C; |
| if (!EvaluateComplex(SubExpr, C, Info)) |
| return false; |
| return Success(C.getComplexIntReal(), E); |
| } |
| |
| case CK_FloatingToIntegral: { |
| APFloat F(0.0); |
| if (!EvaluateFloat(SubExpr, F, Info)) |
| return false; |
| |
| APSInt Value; |
| if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value)) |
| return false; |
| return Success(Value, E); |
| } |
| } |
| |
| llvm_unreachable("unknown cast resulting in integral value"); |
| } |
| |
| bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { |
| if (E->getSubExpr()->getType()->isAnyComplexType()) { |
| ComplexValue LV; |
| if (!EvaluateComplex(E->getSubExpr(), LV, Info)) |
| return false; |
| if (!LV.isComplexInt()) |
| return Error(E); |
| return Success(LV.getComplexIntReal(), E); |
| } |
| |
| return Visit(E->getSubExpr()); |
| } |
| |
| bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { |
| if (E->getSubExpr()->getType()->isComplexIntegerType()) { |
| ComplexValue LV; |
| if (!EvaluateComplex(E->getSubExpr(), LV, Info)) |
| return false; |
| if (!LV.isComplexInt()) |
| return Error(E); |
| return Success(LV.getComplexIntImag(), E); |
| } |
| |
| VisitIgnoredValue(E->getSubExpr()); |
| return Success(0, E); |
| } |
| |
| bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) { |
| return Success(E->getPackLength(), E); |
| } |
| |
| bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) { |
| return Success(E->getValue(), E); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Float Evaluation |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class FloatExprEvaluator |
| : public ExprEvaluatorBase<FloatExprEvaluator, bool> { |
| APFloat &Result; |
| public: |
| FloatExprEvaluator(EvalInfo &info, APFloat &result) |
| : ExprEvaluatorBaseTy(info), Result(result) {} |
| |
| bool Success(const APValue &V, const Expr *e) { |
| Result = V.getFloat(); |
| return true; |
| } |
| |
| bool ZeroInitialization(const Expr *E) { |
| Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType())); |
| return true; |
| } |
| |
| bool VisitCallExpr(const CallExpr *E); |
| |
| bool VisitUnaryOperator(const UnaryOperator *E); |
| bool VisitBinaryOperator(const BinaryOperator *E); |
| bool VisitFloatingLiteral(const FloatingLiteral *E); |
| bool VisitCastExpr(const CastExpr *E); |
| |
| bool VisitUnaryReal(const UnaryOperator *E); |
| bool VisitUnaryImag(const UnaryOperator *E); |
| |
| // FIXME: Missing: array subscript of vector, member of vector |
| }; |
| } // end anonymous namespace |
| |
| static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isRealFloatingType()); |
| return FloatExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| static bool TryEvaluateBuiltinNaN(const ASTContext &Context, |
| QualType ResultTy, |
| const Expr *Arg, |
| bool SNaN, |
| llvm::APFloat &Result) { |
| const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts()); |
| if (!S) return false; |
| |
| const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy); |
| |
| llvm::APInt fill; |
| |
| // Treat empty strings as if they were zero. |
| if (S->getString().empty()) |
| fill = llvm::APInt(32, 0); |
| else if (S->getString().getAsInteger(0, fill)) |
| return false; |
| |
| if (SNaN) |
| Result = llvm::APFloat::getSNaN(Sem, false, &fill); |
| else |
| Result = llvm::APFloat::getQNaN(Sem, false, &fill); |
| return true; |
| } |
| |
| bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) { |
| switch (E->isBuiltinCall()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitCallExpr(E); |
| |
| case Builtin::BI__builtin_huge_val: |
| case Builtin::BI__builtin_huge_valf: |
| case Builtin::BI__builtin_huge_vall: |
| case Builtin::BI__builtin_inf: |
| case Builtin::BI__builtin_inff: |
| case Builtin::BI__builtin_infl: { |
| const llvm::fltSemantics &Sem = |
| Info.Ctx.getFloatTypeSemantics(E->getType()); |
| Result = llvm::APFloat::getInf(Sem); |
| return true; |
| } |
| |
| case Builtin::BI__builtin_nans: |
| case Builtin::BI__builtin_nansf: |
| case Builtin::BI__builtin_nansl: |
| if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), |
| true, Result)) |
| return Error(E); |
| return true; |
| |
| case Builtin::BI__builtin_nan: |
| case Builtin::BI__builtin_nanf: |
| case Builtin::BI__builtin_nanl: |
| // If this is __builtin_nan() turn this into a nan, otherwise we |
| // can't constant fold it. |
| if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), |
| false, Result)) |
| return Error(E); |
| return true; |
| |
| case Builtin::BI__builtin_fabs: |
| case Builtin::BI__builtin_fabsf: |
| case Builtin::BI__builtin_fabsl: |
| if (!EvaluateFloat(E->getArg(0), Result, Info)) |
| return false; |
| |
| if (Result.isNegative()) |
| Result.changeSign(); |
| return true; |
| |
| // FIXME: Builtin::BI__builtin_powi |
| // FIXME: Builtin::BI__builtin_powif |
| // FIXME: Builtin::BI__builtin_powil |
| |
| case Builtin::BI__builtin_copysign: |
| case Builtin::BI__builtin_copysignf: |
| case Builtin::BI__builtin_copysignl: { |
| APFloat RHS(0.); |
| if (!EvaluateFloat(E->getArg(0), Result, Info) || |
| !EvaluateFloat(E->getArg(1), RHS, Info)) |
| return false; |
| Result.copySign(RHS); |
| return true; |
| } |
| } |
| } |
| |
| bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { |
| if (E->getSubExpr()->getType()->isAnyComplexType()) { |
| ComplexValue CV; |
| if (!EvaluateComplex(E->getSubExpr(), CV, Info)) |
| return false; |
| Result = CV.FloatReal; |
| return true; |
| } |
| |
| return Visit(E->getSubExpr()); |
| } |
| |
| bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { |
| if (E->getSubExpr()->getType()->isAnyComplexType()) { |
| ComplexValue CV; |
| if (!EvaluateComplex(E->getSubExpr(), CV, Info)) |
| return false; |
| Result = CV.FloatImag; |
| return true; |
| } |
| |
| VisitIgnoredValue(E->getSubExpr()); |
| const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType()); |
| Result = llvm::APFloat::getZero(Sem); |
| return true; |
| } |
| |
| bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { |
| switch (E->getOpcode()) { |
| default: return Error(E); |
| case UO_Plus: |
| return EvaluateFloat(E->getSubExpr(), Result, Info); |
| case UO_Minus: |
| if (!EvaluateFloat(E->getSubExpr(), Result, Info)) |
| return false; |
| Result.changeSign(); |
| return true; |
| } |
| } |
| |
| bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { |
| if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) |
| return ExprEvaluatorBaseTy::VisitBinaryOperator(E); |
| |
| APFloat RHS(0.0); |
| bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info); |
| if (!LHSOK && !Info.keepEvaluatingAfterFailure()) |
| return false; |
| return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK && |
| handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS); |
| } |
| |
| bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) { |
| Result = E->getValue(); |
| return true; |
| } |
| |
| bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) { |
| const Expr* SubExpr = E->getSubExpr(); |
| |
| switch (E->getCastKind()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| |
| case CK_IntegralToFloating: { |
| APSInt IntResult; |
| return EvaluateInteger(SubExpr, IntResult, Info) && |
| HandleIntToFloatCast(Info, E, SubExpr->getType(), IntResult, |
| E->getType(), Result); |
| } |
| |
| case CK_FloatingCast: { |
| if (!Visit(SubExpr)) |
| return false; |
| return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(), |
| Result); |
| } |
| |
| case CK_FloatingComplexToReal: { |
| ComplexValue V; |
| if (!EvaluateComplex(SubExpr, V, Info)) |
| return false; |
| Result = V.getComplexFloatReal(); |
| return true; |
| } |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Complex Evaluation (for float and integer) |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class ComplexExprEvaluator |
| : public ExprEvaluatorBase<ComplexExprEvaluator, bool> { |
| ComplexValue &Result; |
| |
| public: |
| ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result) |
| : ExprEvaluatorBaseTy(info), Result(Result) {} |
| |
| bool Success(const APValue &V, const Expr *e) { |
| Result.setFrom(V); |
| return true; |
| } |
| |
| bool ZeroInitialization(const Expr *E); |
| |
| //===--------------------------------------------------------------------===// |
| // Visitor Methods |
| //===--------------------------------------------------------------------===// |
| |
| bool VisitImaginaryLiteral(const ImaginaryLiteral *E); |
| bool VisitCastExpr(const CastExpr *E); |
| bool VisitBinaryOperator(const BinaryOperator *E); |
| bool VisitUnaryOperator(const UnaryOperator *E); |
| bool VisitInitListExpr(const InitListExpr *E); |
| }; |
| } // end anonymous namespace |
| |
| static bool EvaluateComplex(const Expr *E, ComplexValue &Result, |
| EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isAnyComplexType()); |
| return ComplexExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) { |
| QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType(); |
| if (ElemTy->isRealFloatingType()) { |
| Result.makeComplexFloat(); |
| APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy)); |
| Result.FloatReal = Zero; |
| Result.FloatImag = Zero; |
| } else { |
| Result.makeComplexInt(); |
| APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy); |
| Result.IntReal = Zero; |
| Result.IntImag = Zero; |
| } |
| return true; |
| } |
| |
| bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) { |
| const Expr* SubExpr = E->getSubExpr(); |
| |
| if (SubExpr->getType()->isRealFloatingType()) { |
| Result.makeComplexFloat(); |
| APFloat &Imag = Result.FloatImag; |
| if (!EvaluateFloat(SubExpr, Imag, Info)) |
| return false; |
| |
| Result.FloatReal = APFloat(Imag.getSemantics()); |
| return true; |
| } else { |
| assert(SubExpr->getType()->isIntegerType() && |
| "Unexpected imaginary literal."); |
| |
| Result.makeComplexInt(); |
| APSInt &Imag = Result.IntImag; |
| if (!EvaluateInteger(SubExpr, Imag, Info)) |
| return false; |
| |
| Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned()); |
| return true; |
| } |
| } |
| |
| bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) { |
| |
| switch (E->getCastKind()) { |
| case CK_BitCast: |
| case CK_BaseToDerived: |
| case CK_DerivedToBase: |
| case CK_UncheckedDerivedToBase: |
| case CK_Dynamic: |
| case CK_ToUnion: |
| case CK_ArrayToPointerDecay: |
| case CK_FunctionToPointerDecay: |
| case CK_NullToPointer: |
| case CK_NullToMemberPointer: |
| case CK_BaseToDerivedMemberPointer: |
| case CK_DerivedToBaseMemberPointer: |
| case CK_MemberPointerToBoolean: |
| case CK_ReinterpretMemberPointer: |
| case CK_ConstructorConversion: |
| case CK_IntegralToPointer: |
| case CK_PointerToIntegral: |
| case CK_PointerToBoolean: |
| case CK_ToVoid: |
| case CK_VectorSplat: |
| case CK_IntegralCast: |
| case CK_IntegralToBoolean: |
| case CK_IntegralToFloating: |
| case CK_FloatingToIntegral: |
| case CK_FloatingToBoolean: |
| case CK_FloatingCast: |
| case CK_CPointerToObjCPointerCast: |
| case CK_BlockPointerToObjCPointerCast: |
| case CK_AnyPointerToBlockPointerCast: |
| case CK_ObjCObjectLValueCast: |
| case CK_FloatingComplexToReal: |
| case CK_FloatingComplexToBoolean: |
| case CK_IntegralComplexToReal: |
| case CK_IntegralComplexToBoolean: |
| case CK_ARCProduceObject: |
| case CK_ARCConsumeObject: |
| case CK_ARCReclaimReturnedObject: |
| case CK_ARCExtendBlockObject: |
| case CK_CopyAndAutoreleaseBlockObject: |
| case CK_BuiltinFnToFnPtr: |
| case CK_ZeroToOCLEvent: |
| case CK_NonAtomicToAtomic: |
| llvm_unreachable("invalid cast kind for complex value"); |
| |
| case CK_LValueToRValue: |
| case CK_AtomicToNonAtomic: |
| case CK_NoOp: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| |
| case CK_Dependent: |
| case CK_LValueBitCast: |
| case CK_UserDefinedConversion: |
| return Error(E); |
| |
| case CK_FloatingRealToComplex: { |
| APFloat &Real = Result.FloatReal; |
| if (!EvaluateFloat(E->getSubExpr(), Real, Info)) |
| return false; |
| |
| Result.makeComplexFloat(); |
| Result.FloatImag = APFloat(Real.getSemantics()); |
| return true; |
| } |
| |
| case CK_FloatingComplexCast: { |
| if (!Visit(E->getSubExpr())) |
| return false; |
| |
| QualType To = E->getType()->getAs<ComplexType>()->getElementType(); |
| QualType From |
| = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType(); |
| |
| return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) && |
| HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag); |
| } |
| |
| case CK_FloatingComplexToIntegralComplex: { |
| if (!Visit(E->getSubExpr())) |
| return false; |
| |
| QualType To = E->getType()->getAs<ComplexType>()->getElementType(); |
| QualType From |
| = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType(); |
| Result.makeComplexInt(); |
| return HandleFloatToIntCast(Info, E, From, Result.FloatReal, |
| To, Result.IntReal) && |
| HandleFloatToIntCast(Info, E, From, Result.FloatImag, |
| To, Result.IntImag); |
| } |
| |
| case CK_IntegralRealToComplex: { |
| APSInt &Real = Result.IntReal; |
| if (!EvaluateInteger(E->getSubExpr(), Real, Info)) |
| return false; |
| |
| Result.makeComplexInt(); |
| Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned()); |
| return true; |
| } |
| |
| case CK_IntegralComplexCast: { |
| if (!Visit(E->getSubExpr())) |
| return false; |
| |
| QualType To = E->getType()->getAs<ComplexType>()->getElementType(); |
| QualType From |
| = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType(); |
| |
| Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal); |
| Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag); |
| return true; |
| } |
| |
| case CK_IntegralComplexToFloatingComplex: { |
| if (!Visit(E->getSubExpr())) |
| return false; |
| |
| QualType To = E->getType()->castAs<ComplexType>()->getElementType(); |
| QualType From |
| = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); |
| Result.makeComplexFloat(); |
| return HandleIntToFloatCast(Info, E, From, Result.IntReal, |
| To, Result.FloatReal) && |
| HandleIntToFloatCast(Info, E, From, Result.IntImag, |
| To, Result.FloatImag); |
| } |
| } |
| |
| llvm_unreachable("unknown cast resulting in complex value"); |
| } |
| |
| bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { |
| if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) |
| return ExprEvaluatorBaseTy::VisitBinaryOperator(E); |
| |
| bool LHSOK = Visit(E->getLHS()); |
| if (!LHSOK && !Info.keepEvaluatingAfterFailure()) |
| return false; |
| |
| ComplexValue RHS; |
| if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK) |
| return false; |
| |
| assert(Result.isComplexFloat() == RHS.isComplexFloat() && |
| "Invalid operands to binary operator."); |
| switch (E->getOpcode()) { |
| default: return Error(E); |
| case BO_Add: |
| if (Result.isComplexFloat()) { |
| Result.getComplexFloatReal().add(RHS.getComplexFloatReal(), |
| APFloat::rmNearestTiesToEven); |
| Result.getComplexFloatImag().add(RHS.getComplexFloatImag(), |
| APFloat::rmNearestTiesToEven); |
| } else { |
| Result.getComplexIntReal() += RHS.getComplexIntReal(); |
| Result.getComplexIntImag() += RHS.getComplexIntImag(); |
| } |
| break; |
| case BO_Sub: |
| if (Result.isComplexFloat()) { |
| Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(), |
| APFloat::rmNearestTiesToEven); |
| Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(), |
| APFloat::rmNearestTiesToEven); |
| } else { |
| Result.getComplexIntReal() -= RHS.getComplexIntReal(); |
| Result.getComplexIntImag() -= RHS.getComplexIntImag(); |
| } |
| break; |
| case BO_Mul: |
| if (Result.isComplexFloat()) { |
| ComplexValue LHS = Result; |
| APFloat &LHS_r = LHS.getComplexFloatReal(); |
| APFloat &LHS_i = LHS.getComplexFloatImag(); |
| APFloat &RHS_r = RHS.getComplexFloatReal(); |
| APFloat &RHS_i = RHS.getComplexFloatImag(); |
| |
| APFloat Tmp = LHS_r; |
| Tmp.multiply(RHS_r, APFloat::rmNearestTiesToEven); |
| Result.getComplexFloatReal() = Tmp; |
| Tmp = LHS_i; |
| Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); |
| Result.getComplexFloatReal().subtract(Tmp, APFloat::rmNearestTiesToEven); |
| |
| Tmp = LHS_r; |
| Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); |
| Result.getComplexFloatImag() = Tmp; |
| Tmp = LHS_i; |
| Tmp.multiply(RHS_r, APFloat::rmNearestTiesToEven); |
| Result.getComplexFloatImag().add(Tmp, APFloat::rmNearestTiesToEven); |
| } else { |
| ComplexValue LHS = Result; |
| Result.getComplexIntReal() = |
| (LHS.getComplexIntReal() * RHS.getComplexIntReal() - |
| LHS.getComplexIntImag() * RHS.getComplexIntImag()); |
| Result.getComplexIntImag() = |
| (LHS.getComplexIntReal() * RHS.getComplexIntImag() + |
| LHS.getComplexIntImag() * RHS.getComplexIntReal()); |
| } |
| break; |
| case BO_Div: |
| if (Result.isComplexFloat()) { |
| ComplexValue LHS = Result; |
| APFloat &LHS_r = LHS.getComplexFloatReal(); |
| APFloat &LHS_i = LHS.getComplexFloatImag(); |
| APFloat &RHS_r = RHS.getComplexFloatReal(); |
| APFloat &RHS_i = RHS.getComplexFloatImag(); |
| APFloat &Res_r = Result.getComplexFloatReal(); |
| APFloat &Res_i = Result.getComplexFloatImag(); |
| |
| APFloat Den = RHS_r; |
| Den.multiply(RHS_r, APFloat::rmNearestTiesToEven); |
| APFloat Tmp = RHS_i; |
| Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); |
| Den.add(Tmp, APFloat::rmNearestTiesToEven); |
| |
| Res_r = LHS_r; |
| Res_r.multiply(RHS_r, APFloat::rmNearestTiesToEven); |
| Tmp = LHS_i; |
| Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); |
| Res_r.add(Tmp, APFloat::rmNearestTiesToEven); |
| Res_r.divide(Den, APFloat::rmNearestTiesToEven); |
| |
| Res_i = LHS_i; |
| Res_i.multiply(RHS_r, APFloat::rmNearestTiesToEven); |
| Tmp = LHS_r; |
| Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); |
| Res_i.subtract(Tmp, APFloat::rmNearestTiesToEven); |
| Res_i.divide(Den, APFloat::rmNearestTiesToEven); |
| } else { |
| if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0) |
| return Error(E, diag::note_expr_divide_by_zero); |
| |
| ComplexValue LHS = Result; |
| APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() + |
| RHS.getComplexIntImag() * RHS.getComplexIntImag(); |
| Result.getComplexIntReal() = |
| (LHS.getComplexIntReal() * RHS.getComplexIntReal() + |
| LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den; |
| Result.getComplexIntImag() = |
| (LHS.getComplexIntImag() * RHS.getComplexIntReal() - |
| LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den; |
| } |
| break; |
| } |
| |
| return true; |
| } |
| |
| bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { |
| // Get the operand value into 'Result'. |
| if (!Visit(E->getSubExpr())) |
| return false; |
| |
| switch (E->getOpcode()) { |
| default: |
| return Error(E); |
| case UO_Extension: |
| return true; |
| case UO_Plus: |
| // The result is always just the subexpr. |
| return true; |
| case UO_Minus: |
| if (Result.isComplexFloat()) { |
| Result.getComplexFloatReal().changeSign(); |
| Result.getComplexFloatImag().changeSign(); |
| } |
| else { |
| Result.getComplexIntReal() = -Result.getComplexIntReal(); |
| Result.getComplexIntImag() = -Result.getComplexIntImag(); |
| } |
| return true; |
| case UO_Not: |
| if (Result.isComplexFloat()) |
| Result.getComplexFloatImag().changeSign(); |
| else |
| Result.getComplexIntImag() = -Result.getComplexIntImag(); |
| return true; |
| } |
| } |
| |
| bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) { |
| if (E->getNumInits() == 2) { |
| if (E->getType()->isComplexType()) { |
| Result.makeComplexFloat(); |
| if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info)) |
| return false; |
| if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info)) |
| return false; |
| } else { |
| Result.makeComplexInt(); |
| if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info)) |
| return false; |
| if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info)) |
| return false; |
| } |
| return true; |
| } |
| return ExprEvaluatorBaseTy::VisitInitListExpr(E); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Atomic expression evaluation, essentially just handling the NonAtomicToAtomic |
| // implicit conversion. |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class AtomicExprEvaluator : |
| public ExprEvaluatorBase<AtomicExprEvaluator, bool> { |
| APValue &Result; |
| public: |
| AtomicExprEvaluator(EvalInfo &Info, APValue &Result) |
| : ExprEvaluatorBaseTy(Info), Result(Result) {} |
| |
| bool Success(const APValue &V, const Expr *E) { |
| Result = V; |
| return true; |
| } |
| |
| bool ZeroInitialization(const Expr *E) { |
| ImplicitValueInitExpr VIE( |
| E->getType()->castAs<AtomicType>()->getValueType()); |
| return Evaluate(Result, Info, &VIE); |
| } |
| |
| bool VisitCastExpr(const CastExpr *E) { |
| switch (E->getCastKind()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| case CK_NonAtomicToAtomic: |
| return Evaluate(Result, Info, E->getSubExpr()); |
| } |
| } |
| }; |
| } // end anonymous namespace |
| |
| static bool EvaluateAtomic(const Expr *E, APValue &Result, EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isAtomicType()); |
| return AtomicExprEvaluator(Info, Result).Visit(E); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Void expression evaluation, primarily for a cast to void on the LHS of a |
| // comma operator |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class VoidExprEvaluator |
| : public ExprEvaluatorBase<VoidExprEvaluator, bool> { |
| public: |
| VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {} |
| |
| bool Success(const APValue &V, const Expr *e) { return true; } |
| |
| bool VisitCastExpr(const CastExpr *E) { |
| switch (E->getCastKind()) { |
| default: |
| return ExprEvaluatorBaseTy::VisitCastExpr(E); |
| case CK_ToVoid: |
| VisitIgnoredValue(E->getSubExpr()); |
| return true; |
| } |
| } |
| }; |
| } // end anonymous namespace |
| |
| static bool EvaluateVoid(const Expr *E, EvalInfo &Info) { |
| assert(E->isRValue() && E->getType()->isVoidType()); |
| return VoidExprEvaluator(Info).Visit(E); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Top level Expr::EvaluateAsRValue method. |
| //===----------------------------------------------------------------------===// |
| |
| static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) { |
| // In C, function designators are not lvalues, but we evaluate them as if they |
| // are. |
| QualType T = E->getType(); |
| if (E->isGLValue() || T->isFunctionType()) { |
| LValue LV; |
| if (!EvaluateLValue(E, LV, Info)) |
| return false; |
| LV.moveInto(Result); |
| } else if (T->isVectorType()) { |
| if (!EvaluateVector(E, Result, Info)) |
| return false; |
| } else if (T->isIntegralOrEnumerationType()) { |
| if (!IntExprEvaluator(Info, Result).Visit(E)) |
| return false; |
| } else if (T->hasPointerRepresentation()) { |
| LValue LV; |
| if (!EvaluatePointer(E, LV, Info)) |
| return false; |
| LV.moveInto(Result); |
| } else if (T->isRealFloatingType()) { |
| llvm::APFloat F(0.0); |
| if (!EvaluateFloat(E, F, Info)) |
| return false; |
| Result = APValue(F); |
| } else if (T->isAnyComplexType()) { |
| ComplexValue C; |
| if (!EvaluateComplex(E, C, Info)) |
| return false; |
| C.moveInto(Result); |
| } else if (T->isMemberPointerType()) { |
| MemberPtr P; |
| if (!EvaluateMemberPointer(E, P, Info)) |
| return false; |
| P.moveInto(Result); |
| return true; |
| } else if (T->isArrayType()) { |
| LValue LV; |
| LV.set(E, Info.CurrentCall->Index); |
| APValue &Value = Info.CurrentCall->createTemporary(E, false); |
| if (!EvaluateArray(E, LV, Value, Info)) |
| return false; |
| Result = Value; |
| } else if (T->isRecordType()) { |
| LValue LV; |
| LV.set(E, Info.CurrentCall->Index); |
| APValue &Value = Info.CurrentCall->createTemporary(E, false); |
| if (!EvaluateRecord(E, LV, Value, Info)) |
| return false; |
| Result = Value; |
| } else if (T->isVoidType()) { |
| if (!Info.getLangOpts().CPlusPlus11) |
| Info.CCEDiag(E, diag::note_constexpr_nonliteral) |
| << E->getType(); |
| if (!EvaluateVoid(E, Info)) |
| return false; |
| } else if (T->isAtomicType()) { |
| if (!EvaluateAtomic(E, Result, Info)) |
| return false; |
| } else if (Info.getLangOpts().CPlusPlus11) { |
| Info.Diag(E, diag::note_constexpr_nonliteral) << E->getType(); |
| return false; |
| } else { |
| Info.Diag(E, diag::note_invalid_subexpr_in_const_expr); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some |
| /// cases, the in-place evaluation is essential, since later initializers for |
| /// an object can indirectly refer to subobjects which were initialized earlier. |
| static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This, |
| const Expr *E, bool AllowNonLiteralTypes) { |
| if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This)) |
| return false; |
| |
| if (E->isRValue()) { |
| // Evaluate arrays and record types in-place, so that later initializers can |
| // refer to earlier-initialized members of the object. |
| if (E->getType()->isArrayType()) |
| return EvaluateArray(E, This, Result, Info); |
| else if (E->getType()->isRecordType()) |
| return EvaluateRecord(E, This, Result, Info); |
| } |
| |
| // For any other type, in-place evaluation is unimportant. |
| return Evaluate(Result, Info, E); |
| } |
| |
| /// EvaluateAsRValue - Try to evaluate this expression, performing an implicit |
| /// lvalue-to-rvalue cast if it is an lvalue. |
| static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) { |
| if (!CheckLiteralType(Info, E)) |
| return false; |
| |
| if (!::Evaluate(Result, Info, E)) |
| return false; |
| |
| if (E->isGLValue()) { |
| LValue LV; |
| LV.setFrom(Info.Ctx, Result); |
| if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result)) |
| return false; |
| } |
| |
| // Check this core constant expression is a constant expression. |
| return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result); |
| } |
| |
| static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result, |
| const ASTContext &Ctx, bool &IsConst) { |
| // Fast-path evaluations of integer literals, since we sometimes see files |
| // containing vast quantities of these. |
| if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) { |
| Result.Val = APValue(APSInt(L->getValue(), |
| L->getType()->isUnsignedIntegerType())); |
| IsConst = true; |
| return true; |
| } |
| |
| // FIXME: Evaluating values of large array and record types can cause |
| // performance problems. Only do so in C++11 for now. |
| if (Exp->isRValue() && (Exp->getType()->isArrayType() || |
| Exp->getType()->isRecordType()) && |
| !Ctx.getLangOpts().CPlusPlus11) { |
| IsConst = false; |
| return true; |
| } |
| return false; |
| } |
| |
| |
| /// EvaluateAsRValue - Return true if this is a constant which we can fold using |
| /// any crazy technique (that has nothing to do with language standards) that |
| /// we want to. If this function returns true, it returns the folded constant |
| /// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion |
| /// will be applied to the result. |
| bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const { |
| bool IsConst; |
| if (FastEvaluateAsRValue(this, Result, Ctx, IsConst)) |
| return IsConst; |
| |
| EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects); |
| return ::EvaluateAsRValue(Info, this, Result.Val); |
| } |
| |
| bool Expr::EvaluateAsBooleanCondition(bool &Result, |
| const ASTContext &Ctx) const { |
| EvalResult Scratch; |
| return EvaluateAsRValue(Scratch, Ctx) && |
| HandleConversionToBool(Scratch.Val, Result); |
| } |
| |
| bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx, |
| SideEffectsKind AllowSideEffects) const { |
| if (!getType()->isIntegralOrEnumerationType()) |
| return false; |
| |
| EvalResult ExprResult; |
| if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isInt() || |
| (!AllowSideEffects && ExprResult.HasSideEffects)) |
| return false; |
| |
| Result = ExprResult.Val.getInt(); |
| return true; |
| } |
| |
| bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const { |
| EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold); |
| |
| LValue LV; |
| if (!EvaluateLValue(this, LV, Info) || Result.HasSideEffects || |
| !CheckLValueConstantExpression(Info, getExprLoc(), |
| Ctx.getLValueReferenceType(getType()), LV)) |
| return false; |
| |
| LV.moveInto(Result.Val); |
| return true; |
| } |
| |
| bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx, |
| const VarDecl *VD, |
| SmallVectorImpl<PartialDiagnosticAt> &Notes) const { |
| // FIXME: Evaluating initializers for large array and record types can cause |
| // performance problems. Only do so in C++11 for now. |
| if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) && |
| !Ctx.getLangOpts().CPlusPlus11) |
| return false; |
| |
| Expr::EvalStatus EStatus; |
| EStatus.Diag = &Notes; |
| |
| EvalInfo InitInfo(Ctx, EStatus, EvalInfo::EM_ConstantFold); |
| InitInfo.setEvaluatingDecl(VD, Value); |
| |
| LValue LVal; |
| LVal.set(VD); |
| |
| // C++11 [basic.start.init]p2: |
| // Variables with static storage duration or thread storage duration shall be |
| // zero-initialized before any other initialization takes place. |
| // This behavior is not present in C. |
| if (Ctx.getLangOpts().CPlusPlus && !VD->hasLocalStorage() && |
| !VD->getType()->isReferenceType()) { |
| ImplicitValueInitExpr VIE(VD->getType()); |
| if (!EvaluateInPlace(Value, InitInfo, LVal, &VIE, |
| /*AllowNonLiteralTypes=*/true)) |
| return false; |
| } |
| |
| if (!EvaluateInPlace(Value, InitInfo, LVal, this, |
| /*AllowNonLiteralTypes=*/true) || |
| EStatus.HasSideEffects) |
| return false; |
| |
| return CheckConstantExpression(InitInfo, VD->getLocation(), VD->getType(), |
| Value); |
| } |
| |
| /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be |
| /// constant folded, but discard the result. |
| bool Expr::isEvaluatable(const ASTContext &Ctx) const { |
| EvalResult Result; |
| return EvaluateAsRValue(Result, Ctx) && !Result.HasSideEffects; |
| } |
| |
| APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx, |
| SmallVectorImpl<PartialDiagnosticAt> *Diag) const { |
| EvalResult EvalResult; |
| EvalResult.Diag = Diag; |
| bool Result = EvaluateAsRValue(EvalResult, Ctx); |
| (void)Result; |
| assert(Result && "Could not evaluate expression"); |
| assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer"); |
| |
| return EvalResult.Val.getInt(); |
| } |
| |
| void Expr::EvaluateForOverflow(const ASTContext &Ctx) const { |
| bool IsConst; |
| EvalResult EvalResult; |
| if (!FastEvaluateAsRValue(this, EvalResult, Ctx, IsConst)) { |
| EvalInfo Info(Ctx, EvalResult, EvalInfo::EM_EvaluateForOverflow); |
| (void)::EvaluateAsRValue(Info, this, EvalResult.Val); |
| } |
| } |
| |
| bool Expr::EvalResult::isGlobalLValue() const { |
| assert(Val.isLValue()); |
| return IsGlobalLValue(Val.getLValueBase()); |
| } |
| |
| |
| /// isIntegerConstantExpr - this recursive routine will test if an expression is |
| /// an integer constant expression. |
| |
| /// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero, |
| /// comma, etc |
| |
| // CheckICE - This function does the fundamental ICE checking: the returned |
| // ICEDiag contains an ICEKind indicating whether the expression is an ICE, |
| // and a (possibly null) SourceLocation indicating the location of the problem. |
| // |
| // Note that to reduce code duplication, this helper does no evaluation |
| // itself; the caller checks whether the expression is evaluatable, and |
| // in the rare cases where CheckICE actually cares about the evaluated |
| // value, it calls into Evalute. |
| |
| namespace { |
| |
| enum ICEKind { |
| /// This expression is an ICE. |
| IK_ICE, |
| /// This expression is not an ICE, but if it isn't evaluated, it's |
| /// a legal subexpression for an ICE. This return value is used to handle |
| /// the comma operator in C99 mode, and non-constant subexpressions. |
| IK_ICEIfUnevaluated, |
| /// This expression is not an ICE, and is not a legal subexpression for one. |
| IK_NotICE |
| }; |
| |
| struct ICEDiag { |
| ICEKind Kind; |
| SourceLocation Loc; |
| |
| ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {} |
| }; |
| |
| } |
| |
| static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); } |
| |
| static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; } |
| |
| static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) { |
| Expr::EvalResult EVResult; |
| if (!E->EvaluateAsRValue(EVResult, Ctx) || EVResult.HasSideEffects || |
| !EVResult.Val.isInt()) |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| |
| return NoDiag(); |
| } |
| |
| static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) { |
| assert(!E->isValueDependent() && "Should not see value dependent exprs!"); |
| if (!E->getType()->isIntegralOrEnumerationType()) |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| |
| switch (E->getStmtClass()) { |
| #define ABSTRACT_STMT(Node) |
| #define STMT(Node, Base) case Expr::Node##Class: |
| #define EXPR(Node, Base) |
| #include "clang/AST/StmtNodes.inc" |
| case Expr::PredefinedExprClass: |
| case Expr::FloatingLiteralClass: |
| case Expr::ImaginaryLiteralClass: |
| case Expr::StringLiteralClass: |
| case Expr::ArraySubscriptExprClass: |
| case Expr::MemberExprClass: |
| case Expr::CompoundAssignOperatorClass: |
| case Expr::CompoundLiteralExprClass: |
| case Expr::ExtVectorElementExprClass: |
| case Expr::DesignatedInitExprClass: |
| case Expr::ImplicitValueInitExprClass: |
| case Expr::ParenListExprClass: |
| case Expr::VAArgExprClass: |
| case Expr::AddrLabelExprClass: |
| case Expr::StmtExprClass: |
| case Expr::CXXMemberCallExprClass: |
| case Expr::CUDAKernelCallExprClass: |
| case Expr::CXXDynamicCastExprClass: |
| case Expr::CXXTypeidExprClass: |
| case Expr::CXXUuidofExprClass: |
| case Expr::MSPropertyRefExprClass: |
| case Expr::CXXNullPtrLiteralExprClass: |
| case Expr::UserDefinedLiteralClass: |
| case Expr::CXXThisExprClass: |
| case Expr::CXXThrowExprClass: |
| case Expr::CXXNewExprClass: |
| case Expr::CXXDeleteExprClass: |
| case Expr::CXXPseudoDestructorExprClass: |
| case Expr::UnresolvedLookupExprClass: |
| case Expr::DependentScopeDeclRefExprClass: |
| case Expr::CXXConstructExprClass: |
| case Expr::CXXStdInitializerListExprClass: |
| case Expr::CXXBindTemporaryExprClass: |
| case Expr::ExprWithCleanupsClass: |
| case Expr::CXXTemporaryObjectExprClass: |
| case Expr::CXXUnresolvedConstructExprClass: |
| case Expr::CXXDependentScopeMemberExprClass: |
| case Expr::UnresolvedMemberExprClass: |
| case Expr::ObjCStringLiteralClass: |
| case Expr::ObjCBoxedExprClass: |
| case Expr::ObjCArrayLiteralClass: |
| case Expr::ObjCDictionaryLiteralClass: |
| case Expr::ObjCEncodeExprClass: |
| case Expr::ObjCMessageExprClass: |
| case Expr::ObjCSelectorExprClass: |
| case Expr::ObjCProtocolExprClass: |
| case Expr::ObjCIvarRefExprClass: |
| case Expr::ObjCPropertyRefExprClass: |
| case Expr::ObjCSubscriptRefExprClass: |
| case Expr::ObjCIsaExprClass: |
| case Expr::ShuffleVectorExprClass: |
| case Expr::ConvertVectorExprClass: |
| case Expr::BlockExprClass: |
| case Expr::NoStmtClass: |
| case Expr::OpaqueValueExprClass: |
| case Expr::PackExpansionExprClass: |
| case Expr::SubstNonTypeTemplateParmPackExprClass: |
| case Expr::FunctionParmPackExprClass: |
| case Expr::AsTypeExprClass: |
| case Expr::ObjCIndirectCopyRestoreExprClass: |
| case Expr::MaterializeTemporaryExprClass: |
| case Expr::PseudoObjectExprClass: |
| case Expr::AtomicExprClass: |
| case Expr::InitListExprClass: |
| case Expr::LambdaExprClass: |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| |
| case Expr::SizeOfPackExprClass: |
| case Expr::GNUNullExprClass: |
| // GCC considers the GNU __null value to be an integral constant expression. |
| return NoDiag(); |
| |
| case Expr::SubstNonTypeTemplateParmExprClass: |
| return |
| CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx); |
| |
| case Expr::ParenExprClass: |
| return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx); |
| case Expr::GenericSelectionExprClass: |
| return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx); |
| case Expr::IntegerLiteralClass: |
| case Expr::CharacterLiteralClass: |
| case Expr::ObjCBoolLiteralExprClass: |
| case Expr::CXXBoolLiteralExprClass: |
| case Expr::CXXScalarValueInitExprClass: |
| case Expr::UnaryTypeTraitExprClass: |
| case Expr::BinaryTypeTraitExprClass: |
| case Expr::TypeTraitExprClass: |
| case Expr::ArrayTypeTraitExprClass: |
| case Expr::ExpressionTraitExprClass: |
| case Expr::CXXNoexceptExprClass: |
| return NoDiag(); |
| case Expr::CallExprClass: |
| case Expr::CXXOperatorCallExprClass: { |
| // C99 6.6/3 allows function calls within unevaluated subexpressions of |
| // constant expressions, but they can never be ICEs because an ICE cannot |
| // contain an operand of (pointer to) function type. |
| const CallExpr *CE = cast<CallExpr>(E); |
| if (CE->isBuiltinCall()) |
| return CheckEvalInICE(E, Ctx); |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| } |
| case Expr::DeclRefExprClass: { |
| if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl())) |
| return NoDiag(); |
| const ValueDecl *D = dyn_cast<ValueDecl>(cast<DeclRefExpr>(E)->getDecl()); |
| if (Ctx.getLangOpts().CPlusPlus && |
| D && IsConstNonVolatile(D->getType())) { |
| // Parameter variables are never constants. Without this check, |
| // getAnyInitializer() can find a default argument, which leads |
| // to chaos. |
| if (isa<ParmVarDecl>(D)) |
| return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation()); |
| |
| // C++ 7.1.5.1p2 |
| // A variable of non-volatile const-qualified integral or enumeration |
| // type initialized by an ICE can be used in ICEs. |
| if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) { |
| if (!Dcl->getType()->isIntegralOrEnumerationType()) |
| return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation()); |
| |
| const VarDecl *VD; |
| // Look for a declaration of this variable that has an initializer, and |
| // check whether it is an ICE. |
| if (Dcl->getAnyInitializer(VD) && VD->checkInitIsICE()) |
| return NoDiag(); |
| else |
| return ICEDiag(IK_NotICE, cast<DeclRefExpr>(E)->getLocation()); |
| } |
| } |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| } |
| case Expr::UnaryOperatorClass: { |
| const UnaryOperator *Exp = cast<UnaryOperator>(E); |
| switch (Exp->getOpcode()) { |
| case UO_PostInc: |
| case UO_PostDec: |
| case UO_PreInc: |
| case UO_PreDec: |
| case UO_AddrOf: |
| case UO_Deref: |
| // C99 6.6/3 allows increment and decrement within unevaluated |
| // subexpressions of constant expressions, but they can never be ICEs |
| // because an ICE cannot contain an lvalue operand. |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| case UO_Extension: |
| case UO_LNot: |
| case UO_Plus: |
| case UO_Minus: |
| case UO_Not: |
| case UO_Real: |
| case UO_Imag: |
| return CheckICE(Exp->getSubExpr(), Ctx); |
| } |
| |
| // OffsetOf falls through here. |
| } |
| case Expr::OffsetOfExprClass: { |
| // Note that per C99, offsetof must be an ICE. And AFAIK, using |
| // EvaluateAsRValue matches the proposed gcc behavior for cases like |
| // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect |
| // compliance: we should warn earlier for offsetof expressions with |
| // array subscripts that aren't ICEs, and if the array subscripts |
| // are ICEs, the value of the offsetof must be an integer constant. |
| return CheckEvalInICE(E, Ctx); |
| } |
| case Expr::UnaryExprOrTypeTraitExprClass: { |
| const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E); |
| if ((Exp->getKind() == UETT_SizeOf) && |
| Exp->getTypeOfArgument()->isVariableArrayType()) |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| return NoDiag(); |
| } |
| case Expr::BinaryOperatorClass: { |
| const BinaryOperator *Exp = cast<BinaryOperator>(E); |
| switch (Exp->getOpcode()) { |
| case BO_PtrMemD: |
| case BO_PtrMemI: |
| case BO_Assign: |
| case BO_MulAssign: |
| case BO_DivAssign: |
| case BO_RemAssign: |
| case BO_AddAssign: |
| case BO_SubAssign: |
| case BO_ShlAssign: |
| case BO_ShrAssign: |
| case BO_AndAssign: |
| case BO_XorAssign: |
| case BO_OrAssign: |
| // C99 6.6/3 allows assignments within unevaluated subexpressions of |
| // constant expressions, but they can never be ICEs because an ICE cannot |
| // contain an lvalue operand. |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| |
| case BO_Mul: |
| case BO_Div: |
| case BO_Rem: |
| case BO_Add: |
| case BO_Sub: |
| case BO_Shl: |
| case BO_Shr: |
| case BO_LT: |
| case BO_GT: |
| case BO_LE: |
| case BO_GE: |
| case BO_EQ: |
| case BO_NE: |
| case BO_And: |
| case BO_Xor: |
| case BO_Or: |
| case BO_Comma: { |
| ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); |
| ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); |
| if (Exp->getOpcode() == BO_Div || |
| Exp->getOpcode() == BO_Rem) { |
| // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure |
| // we don't evaluate one. |
| if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) { |
| llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx); |
| if (REval == 0) |
| return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart()); |
| if (REval.isSigned() && REval.isAllOnesValue()) { |
| llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx); |
| if (LEval.isMinSignedValue()) |
| return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart()); |
| } |
| } |
| } |
| if (Exp->getOpcode() == BO_Comma) { |
| if (Ctx.getLangOpts().C99) { |
| // C99 6.6p3 introduces a strange edge case: comma can be in an ICE |
| // if it isn't evaluated. |
| if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) |
| return ICEDiag(IK_ICEIfUnevaluated, E->getLocStart()); |
| } else { |
| // In both C89 and C++, commas in ICEs are illegal. |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| } |
| } |
| return Worst(LHSResult, RHSResult); |
| } |
| case BO_LAnd: |
| case BO_LOr: { |
| ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); |
| ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); |
| if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) { |
| // Rare case where the RHS has a comma "side-effect"; we need |
| // to actually check the condition to see whether the side |
| // with the comma is evaluated. |
| if ((Exp->getOpcode() == BO_LAnd) != |
| (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0)) |
| return RHSResult; |
| return NoDiag(); |
| } |
| |
| return Worst(LHSResult, RHSResult); |
| } |
| } |
| } |
| case Expr::ImplicitCastExprClass: |
| case Expr::CStyleCastExprClass: |
| case Expr::CXXFunctionalCastExprClass: |
| case Expr::CXXStaticCastExprClass: |
| case Expr::CXXReinterpretCastExprClass: |
| case Expr::CXXConstCastExprClass: |
| case Expr::ObjCBridgedCastExprClass: { |
| const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr(); |
| if (isa<ExplicitCastExpr>(E)) { |
| if (const FloatingLiteral *FL |
| = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) { |
| unsigned DestWidth = Ctx.getIntWidth(E->getType()); |
| bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType(); |
| APSInt IgnoredVal(DestWidth, !DestSigned); |
| bool Ignored; |
| // If the value does not fit in the destination type, the behavior is |
| // undefined, so we are not required to treat it as a constant |
| // expression. |
| if (FL->getValue().convertToInteger(IgnoredVal, |
| llvm::APFloat::rmTowardZero, |
| &Ignored) & APFloat::opInvalidOp) |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| return NoDiag(); |
| } |
| } |
| switch (cast<CastExpr>(E)->getCastKind()) { |
| case CK_LValueToRValue: |
| case CK_AtomicToNonAtomic: |
| case CK_NonAtomicToAtomic: |
| case CK_NoOp: |
| case CK_IntegralToBoolean: |
| case CK_IntegralCast: |
| return CheckICE(SubExpr, Ctx); |
| default: |
| return ICEDiag(IK_NotICE, E->getLocStart()); |
| } |
| } |
| case Expr::BinaryConditionalOperatorClass: { |
| const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E); |
| ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx); |
| if (CommonResult.Kind == IK_NotICE) return CommonResult; |
| ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); |
| if (FalseResult.Kind == IK_NotICE) return FalseResult; |
| if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult; |
| if (FalseResult.Kind == IK_ICEIfUnevaluated && |
| Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag(); |
| return FalseResult; |
| } |
| case Expr::ConditionalOperatorClass: { |
| const ConditionalOperator *Exp = cast<ConditionalOperator>(E); |
| // If the condition (ignoring parens) is a __builtin_constant_p call, |
| // then only the true side is actually considered in an integer constant |
| // expression, and it is fully evaluated. This is an important GNU |
| // extension. See GCC PR38377 for discussion. |
| if (const CallExpr *CallCE |
| = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts())) |
| if (CallCE->isBuiltinCall() == Builtin::BI__builtin_constant_p) |
| return CheckEvalInICE(E, Ctx); |
| ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx); |
| if (CondResult.Kind == IK_NotICE) |
| return CondResult; |
| |
| ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx); |
| ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); |
| |
| if (TrueResult.Kind == IK_NotICE) |
| return TrueResult; |
| if (FalseResult.Kind == IK_NotICE) |
| return FalseResult; |
| if (CondResult.Kind == IK_ICEIfUnevaluated) |
| return CondResult; |
| if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE) |
| return NoDiag(); |
| // Rare case where the diagnostics depend on which side is evaluated |
| // Note that if we get here, CondResult is 0, and at least one of |
| // TrueResult and FalseResult is non-zero. |
| if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0) |
| return FalseResult; |
| return TrueResult; |
| } |
| case Expr::CXXDefaultArgExprClass: |
| return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx); |
| case Expr::CXXDefaultInitExprClass: |
| return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx); |
| case Expr::ChooseExprClass: { |
| return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx); |
| } |
| } |
| |
| llvm_unreachable("Invalid StmtClass!"); |
| } |
| |
| /// Evaluate an expression as a C++11 integral constant expression. |
| static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx, |
| const Expr *E, |
| llvm::APSInt *Value, |
| SourceLocation *Loc) { |
| if (!E->getType()->isIntegralOrEnumerationType()) { |
| if (Loc) *Loc = E->getExprLoc(); |
| return false; |
| } |
| |
| APValue Result; |
| if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc)) |
| return false; |
| |
| assert(Result.isInt() && "pointer cast to int is not an ICE"); |
| if (Value) *Value = Result.getInt(); |
| return true; |
| } |
| |
| bool Expr::isIntegerConstantExpr(const ASTContext &Ctx, |
| SourceLocation *Loc) const { |
| if (Ctx.getLangOpts().CPlusPlus11) |
| return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, 0, Loc); |
| |
| ICEDiag D = CheckICE(this, Ctx); |
| if (D.Kind != IK_ICE) { |
| if (Loc) *Loc = D.Loc; |
| return false; |
| } |
| return true; |
| } |
| |
| bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, const ASTContext &Ctx, |
| SourceLocation *Loc, bool isEvaluated) const { |
| if (Ctx.getLangOpts().CPlusPlus11) |
| return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc); |
| |
| if (!isIntegerConstantExpr(Ctx, Loc)) |
| return false; |
| if (!EvaluateAsInt(Value, Ctx)) |
| llvm_unreachable("ICE cannot be evaluated!"); |
| return true; |
| } |
| |
| bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const { |
| return CheckICE(this, Ctx).Kind == IK_ICE; |
| } |
| |
| bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result, |
| SourceLocation *Loc) const { |
| // We support this checking in C++98 mode in order to diagnose compatibility |
| // issues. |
| assert(Ctx.getLangOpts().CPlusPlus); |
| |
| // Build evaluation settings. |
| Expr::EvalStatus Status; |
| SmallVector<PartialDiagnosticAt, 8> Diags; |
| Status.Diag = &Diags; |
| EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression); |
| |
| APValue Scratch; |
| bool IsConstExpr = ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch); |
| |
| if (!Diags.empty()) { |
| IsConstExpr = false; |
| if (Loc) *Loc = Diags[0].first; |
| } else if (!IsConstExpr) { |
| // FIXME: This shouldn't happen. |
| if (Loc) *Loc = getExprLoc(); |
| } |
| |
| return IsConstExpr; |
| } |
| |
| bool Expr::isPotentialConstantExpr(const FunctionDecl *FD, |
| SmallVectorImpl< |
| PartialDiagnosticAt> &Diags) { |
| // FIXME: It would be useful to check constexpr function templates, but at the |
| // moment the constant expression evaluator cannot cope with the non-rigorous |
| // ASTs which we build for dependent expressions. |
| if (FD->isDependentContext()) |
| return true; |
| |
| Expr::EvalStatus Status; |
| Status.Diag = &Diags; |
| |
| EvalInfo Info(FD->getASTContext(), Status, |
| EvalInfo::EM_PotentialConstantExpression); |
| |
| const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); |
| const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : 0; |
| |
| // Fabricate an arbitrary expression on the stack and pretend that it |
| // is a temporary being used as the 'this' pointer. |
| LValue This; |
| ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy); |
| This.set(&VIE, Info.CurrentCall->Index); |
| |
| ArrayRef<const Expr*> Args; |
| |
| SourceLocation Loc = FD->getLocation(); |
| |
| APValue Scratch; |
| if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { |
| // Evaluate the call as a constant initializer, to allow the construction |
| // of objects of non-literal types. |
| Info.setEvaluatingDecl(This.getLValueBase(), Scratch); |
| HandleConstructorCall(Loc, This, Args, CD, Info, Scratch); |
| } else |
| HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : 0, |
| Args, FD->getBody(), Info, Scratch); |
| |
| return Diags.empty(); |
| } |