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Diffstat (limited to 'contrib/llvm/tools/clang/lib/AST/ExprConstant.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/AST/ExprConstant.cpp | 2650 |
1 files changed, 2650 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/AST/ExprConstant.cpp b/contrib/llvm/tools/clang/lib/AST/ExprConstant.cpp new file mode 100644 index 0000000..dc61401 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/AST/ExprConstant.cpp @@ -0,0 +1,2650 @@ +//===--- 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. +// +//===----------------------------------------------------------------------===// + +#include "clang/AST/APValue.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/CharUnits.h" +#include "clang/AST/RecordLayout.h" +#include "clang/AST/StmtVisitor.h" +#include "clang/AST/TypeLoc.h" +#include "clang/AST/ASTDiagnostic.h" +#include "clang/AST/Expr.h" +#include "clang/Basic/Builtins.h" +#include "clang/Basic/TargetInfo.h" +#include "llvm/ADT/SmallString.h" +#include <cstring> + +using namespace clang; +using llvm::APSInt; +using llvm::APFloat; + +/// 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; + + /// EvalResult - Contains information about the evaluation. + Expr::EvalResult &EvalResult; + + EvalInfo(ASTContext &ctx, Expr::EvalResult& evalresult) + : Ctx(ctx), EvalResult(evalresult) {} +}; + +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) { + if (isComplexFloat()) + v = APValue(FloatReal, FloatImag); + else + v = APValue(IntReal, IntImag); + } + }; + + struct LValue { + Expr *Base; + CharUnits Offset; + + Expr *getLValueBase() { return Base; } + CharUnits getLValueOffset() { return Offset; } + + void moveInto(APValue &v) { + v = APValue(Base, Offset); + } + }; +} + +static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info); +static bool EvaluatePointer(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); + +//===----------------------------------------------------------------------===// +// Misc utilities +//===----------------------------------------------------------------------===// + +static bool IsGlobalLValue(const Expr* E) { + if (!E) return true; + + if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { + if (isa<FunctionDecl>(DRE->getDecl())) + return true; + if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) + return VD->hasGlobalStorage(); + return false; + } + + if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(E)) + return CLE->isFileScope(); + + return true; +} + +static bool EvalPointerValueAsBool(LValue& Value, bool& Result) { + const Expr* Base = Value.Base; + + // A null base expression indicates a null pointer. These are always + // evaluatable, and they are false unless the offset is zero. + if (!Base) { + Result = !Value.Offset.isZero(); + return true; + } + + // Require the base expression to be a global l-value. + if (!IsGlobalLValue(Base)) return false; + + // We have a non-null base expression. These are generally known to + // be true, but if it'a decl-ref to a weak symbol it can be null at + // runtime. + Result = true; + + const DeclRefExpr* DeclRef = dyn_cast<DeclRefExpr>(Base); + if (!DeclRef) + return true; + + // If it's a weak symbol, it isn't constant-evaluable. + const ValueDecl* Decl = DeclRef->getDecl(); + if (Decl->hasAttr<WeakAttr>() || + Decl->hasAttr<WeakRefAttr>() || + Decl->hasAttr<WeakImportAttr>()) + return false; + + return true; +} + +static bool HandleConversionToBool(const Expr* E, bool& Result, + EvalInfo &Info) { + if (E->getType()->isIntegralType()) { + APSInt IntResult; + if (!EvaluateInteger(E, IntResult, Info)) + return false; + Result = IntResult != 0; + return true; + } else if (E->getType()->isRealFloatingType()) { + APFloat FloatResult(0.0); + if (!EvaluateFloat(E, FloatResult, Info)) + return false; + Result = !FloatResult.isZero(); + return true; + } else if (E->getType()->hasPointerRepresentation()) { + LValue PointerResult; + if (!EvaluatePointer(E, PointerResult, Info)) + return false; + return EvalPointerValueAsBool(PointerResult, Result); + } else if (E->getType()->isAnyComplexType()) { + ComplexValue ComplexResult; + if (!EvaluateComplex(E, ComplexResult, Info)) + return false; + if (ComplexResult.isComplexFloat()) { + Result = !ComplexResult.getComplexFloatReal().isZero() || + !ComplexResult.getComplexFloatImag().isZero(); + } else { + Result = ComplexResult.getComplexIntReal().getBoolValue() || + ComplexResult.getComplexIntImag().getBoolValue(); + } + return true; + } + + return false; +} + +static APSInt HandleFloatToIntCast(QualType DestType, QualType SrcType, + APFloat &Value, ASTContext &Ctx) { + unsigned DestWidth = Ctx.getIntWidth(DestType); + // Determine whether we are converting to unsigned or signed. + bool DestSigned = DestType->isSignedIntegerType(); + + // FIXME: Warning for overflow. + uint64_t Space[4]; + bool ignored; + (void)Value.convertToInteger(Space, DestWidth, DestSigned, + llvm::APFloat::rmTowardZero, &ignored); + return APSInt(llvm::APInt(DestWidth, 4, Space), !DestSigned); +} + +static APFloat HandleFloatToFloatCast(QualType DestType, QualType SrcType, + APFloat &Value, ASTContext &Ctx) { + bool ignored; + APFloat Result = Value; + Result.convert(Ctx.getFloatTypeSemantics(DestType), + APFloat::rmNearestTiesToEven, &ignored); + return Result; +} + +static APSInt HandleIntToIntCast(QualType DestType, QualType SrcType, + APSInt &Value, ASTContext &Ctx) { + unsigned DestWidth = 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.extOrTrunc(DestWidth); + Result.setIsUnsigned(DestType->isUnsignedIntegerType()); + return Result; +} + +static APFloat HandleIntToFloatCast(QualType DestType, QualType SrcType, + APSInt &Value, ASTContext &Ctx) { + + APFloat Result(Ctx.getFloatTypeSemantics(DestType), 1); + Result.convertFromAPInt(Value, Value.isSigned(), + APFloat::rmNearestTiesToEven); + return Result; +} + +namespace { +class HasSideEffect + : public StmtVisitor<HasSideEffect, bool> { + EvalInfo &Info; +public: + + HasSideEffect(EvalInfo &info) : Info(info) {} + + // Unhandled nodes conservatively default to having side effects. + bool VisitStmt(Stmt *S) { + return true; + } + + bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + bool VisitDeclRefExpr(DeclRefExpr *E) { + if (Info.Ctx.getCanonicalType(E->getType()).isVolatileQualified()) + return true; + return false; + } + // We don't want to evaluate BlockExprs multiple times, as they generate + // a ton of code. + bool VisitBlockExpr(BlockExpr *E) { return true; } + bool VisitPredefinedExpr(PredefinedExpr *E) { return false; } + bool VisitCompoundLiteralExpr(CompoundLiteralExpr *E) + { return Visit(E->getInitializer()); } + bool VisitMemberExpr(MemberExpr *E) { return Visit(E->getBase()); } + bool VisitIntegerLiteral(IntegerLiteral *E) { return false; } + bool VisitFloatingLiteral(FloatingLiteral *E) { return false; } + bool VisitStringLiteral(StringLiteral *E) { return false; } + bool VisitCharacterLiteral(CharacterLiteral *E) { return false; } + bool VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E) { return false; } + bool VisitArraySubscriptExpr(ArraySubscriptExpr *E) + { return Visit(E->getLHS()) || Visit(E->getRHS()); } + bool VisitChooseExpr(ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + bool VisitCastExpr(CastExpr *E) { return Visit(E->getSubExpr()); } + bool VisitBinAssign(BinaryOperator *E) { return true; } + bool VisitCompoundAssignOperator(BinaryOperator *E) { return true; } + bool VisitBinaryOperator(BinaryOperator *E) + { return Visit(E->getLHS()) || Visit(E->getRHS()); } + bool VisitUnaryPreInc(UnaryOperator *E) { return true; } + bool VisitUnaryPostInc(UnaryOperator *E) { return true; } + bool VisitUnaryPreDec(UnaryOperator *E) { return true; } + bool VisitUnaryPostDec(UnaryOperator *E) { return true; } + bool VisitUnaryDeref(UnaryOperator *E) { + if (Info.Ctx.getCanonicalType(E->getType()).isVolatileQualified()) + return true; + return Visit(E->getSubExpr()); + } + bool VisitUnaryOperator(UnaryOperator *E) { return Visit(E->getSubExpr()); } + + // Has side effects if any element does. + bool VisitInitListExpr(InitListExpr *E) { + for (unsigned i = 0, e = E->getNumInits(); i != e; ++i) + if (Visit(E->getInit(i))) return true; + return false; + } +}; + +} // end anonymous namespace + +//===----------------------------------------------------------------------===// +// LValue Evaluation +//===----------------------------------------------------------------------===// +namespace { +class LValueExprEvaluator + : public StmtVisitor<LValueExprEvaluator, bool> { + EvalInfo &Info; + LValue &Result; + + bool Success(Expr *E) { + Result.Base = E; + Result.Offset = CharUnits::Zero(); + return true; + } +public: + + LValueExprEvaluator(EvalInfo &info, LValue &Result) : + Info(info), Result(Result) {} + + bool VisitStmt(Stmt *S) { + return false; + } + + bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + bool VisitDeclRefExpr(DeclRefExpr *E); + bool VisitPredefinedExpr(PredefinedExpr *E) { return Success(E); } + bool VisitCompoundLiteralExpr(CompoundLiteralExpr *E); + bool VisitMemberExpr(MemberExpr *E); + bool VisitStringLiteral(StringLiteral *E) { return Success(E); } + bool VisitObjCEncodeExpr(ObjCEncodeExpr *E) { return Success(E); } + bool VisitArraySubscriptExpr(ArraySubscriptExpr *E); + bool VisitUnaryDeref(UnaryOperator *E); + bool VisitUnaryExtension(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + bool VisitChooseExpr(const ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + + bool VisitCastExpr(CastExpr *E) { + switch (E->getCastKind()) { + default: + return false; + + case CastExpr::CK_NoOp: + return Visit(E->getSubExpr()); + } + } + // FIXME: Missing: __real__, __imag__ +}; +} // end anonymous namespace + +static bool EvaluateLValue(const Expr* E, LValue& Result, EvalInfo &Info) { + return LValueExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E)); +} + +bool LValueExprEvaluator::VisitDeclRefExpr(DeclRefExpr *E) { + if (isa<FunctionDecl>(E->getDecl())) { + return Success(E); + } else if (VarDecl* VD = dyn_cast<VarDecl>(E->getDecl())) { + if (!VD->getType()->isReferenceType()) + return Success(E); + // Reference parameters can refer to anything even if they have an + // "initializer" in the form of a default argument. + if (isa<ParmVarDecl>(VD)) + return false; + // FIXME: Check whether VD might be overridden! + if (const Expr *Init = VD->getAnyInitializer()) + return Visit(const_cast<Expr *>(Init)); + } + + return false; +} + +bool LValueExprEvaluator::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { + return Success(E); +} + +bool LValueExprEvaluator::VisitMemberExpr(MemberExpr *E) { + QualType Ty; + if (E->isArrow()) { + if (!EvaluatePointer(E->getBase(), Result, Info)) + return false; + Ty = E->getBase()->getType()->getAs<PointerType>()->getPointeeType(); + } else { + if (!Visit(E->getBase())) + return false; + Ty = E->getBase()->getType(); + } + + RecordDecl *RD = Ty->getAs<RecordType>()->getDecl(); + const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); + + FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl()); + if (!FD) // FIXME: deal with other kinds of member expressions + return false; + + if (FD->getType()->isReferenceType()) + return false; + + // FIXME: This is linear time. + unsigned i = 0; + for (RecordDecl::field_iterator Field = RD->field_begin(), + FieldEnd = RD->field_end(); + Field != FieldEnd; (void)++Field, ++i) { + if (*Field == FD) + break; + } + + Result.Offset += CharUnits::fromQuantity(RL.getFieldOffset(i) / 8); + return true; +} + +bool LValueExprEvaluator::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { + if (!EvaluatePointer(E->getBase(), Result, Info)) + return false; + + APSInt Index; + if (!EvaluateInteger(E->getIdx(), Index, Info)) + return false; + + CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(E->getType()); + Result.Offset += Index.getSExtValue() * ElementSize; + return true; +} + +bool LValueExprEvaluator::VisitUnaryDeref(UnaryOperator *E) { + return EvaluatePointer(E->getSubExpr(), Result, Info); +} + +//===----------------------------------------------------------------------===// +// Pointer Evaluation +//===----------------------------------------------------------------------===// + +namespace { +class PointerExprEvaluator + : public StmtVisitor<PointerExprEvaluator, bool> { + EvalInfo &Info; + LValue &Result; + + bool Success(Expr *E) { + Result.Base = E; + Result.Offset = CharUnits::Zero(); + return true; + } +public: + + PointerExprEvaluator(EvalInfo &info, LValue &Result) + : Info(info), Result(Result) {} + + bool VisitStmt(Stmt *S) { + return false; + } + + bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + + bool VisitBinaryOperator(const BinaryOperator *E); + bool VisitCastExpr(CastExpr* E); + bool VisitUnaryExtension(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + bool VisitUnaryAddrOf(const UnaryOperator *E); + bool VisitObjCStringLiteral(ObjCStringLiteral *E) + { return Success(E); } + bool VisitAddrLabelExpr(AddrLabelExpr *E) + { return Success(E); } + bool VisitCallExpr(CallExpr *E); + bool VisitBlockExpr(BlockExpr *E) { + if (!E->hasBlockDeclRefExprs()) + return Success(E); + return false; + } + bool VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) + { return Success((Expr*)0); } + bool VisitConditionalOperator(ConditionalOperator *E); + bool VisitChooseExpr(ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + bool VisitCXXNullPtrLiteralExpr(CXXNullPtrLiteralExpr *E) + { return Success((Expr*)0); } + // FIXME: Missing: @protocol, @selector +}; +} // end anonymous namespace + +static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info) { + assert(E->getType()->hasPointerRepresentation()); + return PointerExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E)); +} + +bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { + if (E->getOpcode() != BinaryOperator::Add && + E->getOpcode() != BinaryOperator::Sub) + return false; + + const Expr *PExp = E->getLHS(); + const Expr *IExp = E->getRHS(); + if (IExp->getType()->isPointerType()) + std::swap(PExp, IExp); + + if (!EvaluatePointer(PExp, Result, Info)) + return false; + + llvm::APSInt Offset; + if (!EvaluateInteger(IExp, Offset, Info)) + return false; + int64_t AdditionalOffset + = Offset.isSigned() ? Offset.getSExtValue() + : static_cast<int64_t>(Offset.getZExtValue()); + + // Compute the new offset in the appropriate width. + + QualType PointeeType = + PExp->getType()->getAs<PointerType>()->getPointeeType(); + CharUnits SizeOfPointee; + + // Explicitly handle GNU void* and function pointer arithmetic extensions. + if (PointeeType->isVoidType() || PointeeType->isFunctionType()) + SizeOfPointee = CharUnits::One(); + else + SizeOfPointee = Info.Ctx.getTypeSizeInChars(PointeeType); + + if (E->getOpcode() == BinaryOperator::Add) + Result.Offset += AdditionalOffset * SizeOfPointee; + else + Result.Offset -= AdditionalOffset * SizeOfPointee; + + return true; +} + +bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { + return EvaluateLValue(E->getSubExpr(), Result, Info); +} + + +bool PointerExprEvaluator::VisitCastExpr(CastExpr* E) { + Expr* SubExpr = E->getSubExpr(); + + switch (E->getCastKind()) { + default: + break; + + case CastExpr::CK_Unknown: { + // FIXME: The handling for CK_Unknown is ugly/shouldn't be necessary! + + // Check for pointer->pointer cast + if (SubExpr->getType()->isPointerType() || + SubExpr->getType()->isObjCObjectPointerType() || + SubExpr->getType()->isNullPtrType() || + SubExpr->getType()->isBlockPointerType()) + return Visit(SubExpr); + + if (SubExpr->getType()->isIntegralType()) { + APValue Value; + if (!EvaluateIntegerOrLValue(SubExpr, Value, Info)) + break; + + if (Value.isInt()) { + Value.getInt().extOrTrunc((unsigned)Info.Ctx.getTypeSize(E->getType())); + Result.Base = 0; + Result.Offset = CharUnits::fromQuantity(Value.getInt().getZExtValue()); + return true; + } else { + Result.Base = Value.getLValueBase(); + Result.Offset = Value.getLValueOffset(); + return true; + } + } + break; + } + + case CastExpr::CK_NoOp: + case CastExpr::CK_BitCast: + case CastExpr::CK_AnyPointerToObjCPointerCast: + case CastExpr::CK_AnyPointerToBlockPointerCast: + return Visit(SubExpr); + + case CastExpr::CK_IntegralToPointer: { + APValue Value; + if (!EvaluateIntegerOrLValue(SubExpr, Value, Info)) + break; + + if (Value.isInt()) { + Value.getInt().extOrTrunc((unsigned)Info.Ctx.getTypeSize(E->getType())); + Result.Base = 0; + Result.Offset = CharUnits::fromQuantity(Value.getInt().getZExtValue()); + return true; + } else { + // Cast is of an lvalue, no need to change value. + Result.Base = Value.getLValueBase(); + Result.Offset = Value.getLValueOffset(); + return true; + } + } + case CastExpr::CK_ArrayToPointerDecay: + case CastExpr::CK_FunctionToPointerDecay: + return EvaluateLValue(SubExpr, Result, Info); + } + + return false; +} + +bool PointerExprEvaluator::VisitCallExpr(CallExpr *E) { + if (E->isBuiltinCall(Info.Ctx) == + Builtin::BI__builtin___CFStringMakeConstantString || + E->isBuiltinCall(Info.Ctx) == + Builtin::BI__builtin___NSStringMakeConstantString) + return Success(E); + return false; +} + +bool PointerExprEvaluator::VisitConditionalOperator(ConditionalOperator *E) { + bool BoolResult; + if (!HandleConversionToBool(E->getCond(), BoolResult, Info)) + return false; + + Expr* EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr(); + return Visit(EvalExpr); +} + +//===----------------------------------------------------------------------===// +// Vector Evaluation +//===----------------------------------------------------------------------===// + +namespace { + class VectorExprEvaluator + : public StmtVisitor<VectorExprEvaluator, APValue> { + EvalInfo &Info; + APValue GetZeroVector(QualType VecType); + public: + + VectorExprEvaluator(EvalInfo &info) : Info(info) {} + + APValue VisitStmt(Stmt *S) { + return APValue(); + } + + APValue VisitParenExpr(ParenExpr *E) + { return Visit(E->getSubExpr()); } + APValue VisitUnaryExtension(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + APValue VisitUnaryPlus(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + APValue VisitUnaryReal(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + APValue VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) + { return GetZeroVector(E->getType()); } + APValue VisitCastExpr(const CastExpr* E); + APValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E); + APValue VisitInitListExpr(const InitListExpr *E); + APValue VisitConditionalOperator(const ConditionalOperator *E); + APValue VisitChooseExpr(const ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + APValue VisitUnaryImag(const UnaryOperator *E); + // FIXME: Missing: unary -, unary ~, binary add/sub/mul/div, + // binary comparisons, binary and/or/xor, + // shufflevector, ExtVectorElementExpr + // (Note that these require implementing conversions + // between vector types.) + }; +} // end anonymous namespace + +static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) { + if (!E->getType()->isVectorType()) + return false; + Result = VectorExprEvaluator(Info).Visit(const_cast<Expr*>(E)); + return !Result.isUninit(); +} + +APValue VectorExprEvaluator::VisitCastExpr(const CastExpr* E) { + const VectorType *VTy = E->getType()->getAs<VectorType>(); + QualType EltTy = VTy->getElementType(); + unsigned NElts = VTy->getNumElements(); + unsigned EltWidth = Info.Ctx.getTypeSize(EltTy); + + const Expr* SE = E->getSubExpr(); + QualType SETy = SE->getType(); + APValue Result = APValue(); + + // Check for vector->vector bitcast and scalar->vector splat. + if (SETy->isVectorType()) { + return this->Visit(const_cast<Expr*>(SE)); + } else if (SETy->isIntegerType()) { + APSInt IntResult; + if (!EvaluateInteger(SE, IntResult, Info)) + return APValue(); + Result = APValue(IntResult); + } else if (SETy->isRealFloatingType()) { + APFloat F(0.0); + if (!EvaluateFloat(SE, F, Info)) + return APValue(); + Result = APValue(F); + } else + return APValue(); + + // For casts of a scalar to ExtVector, convert the scalar to the element type + // and splat it to all elements. + if (E->getType()->isExtVectorType()) { + if (EltTy->isIntegerType() && Result.isInt()) + Result = APValue(HandleIntToIntCast(EltTy, SETy, Result.getInt(), + Info.Ctx)); + else if (EltTy->isIntegerType()) + Result = APValue(HandleFloatToIntCast(EltTy, SETy, Result.getFloat(), + Info.Ctx)); + else if (EltTy->isRealFloatingType() && Result.isInt()) + Result = APValue(HandleIntToFloatCast(EltTy, SETy, Result.getInt(), + Info.Ctx)); + else if (EltTy->isRealFloatingType()) + Result = APValue(HandleFloatToFloatCast(EltTy, SETy, Result.getFloat(), + Info.Ctx)); + else + return APValue(); + + // Splat and create vector APValue. + llvm::SmallVector<APValue, 4> Elts(NElts, Result); + return APValue(&Elts[0], Elts.size()); + } + + // For casts of a scalar to regular gcc-style vector type, bitcast the scalar + // to the vector. To construct the APValue vector initializer, bitcast the + // initializing value to an APInt, and shift out the bits pertaining to each + // element. + APSInt Init; + Init = Result.isInt() ? Result.getInt() : Result.getFloat().bitcastToAPInt(); + + llvm::SmallVector<APValue, 4> Elts; + for (unsigned i = 0; i != NElts; ++i) { + APSInt Tmp = Init; + Tmp.extOrTrunc(EltWidth); + + if (EltTy->isIntegerType()) + Elts.push_back(APValue(Tmp)); + else if (EltTy->isRealFloatingType()) + Elts.push_back(APValue(APFloat(Tmp))); + else + return APValue(); + + Init >>= EltWidth; + } + return APValue(&Elts[0], Elts.size()); +} + +APValue +VectorExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { + return this->Visit(const_cast<Expr*>(E->getInitializer())); +} + +APValue +VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) { + const VectorType *VT = E->getType()->getAs<VectorType>(); + unsigned NumInits = E->getNumInits(); + unsigned NumElements = VT->getNumElements(); + + QualType EltTy = VT->getElementType(); + llvm::SmallVector<APValue, 4> Elements; + + for (unsigned i = 0; i < NumElements; i++) { + if (EltTy->isIntegerType()) { + llvm::APSInt sInt(32); + if (i < NumInits) { + if (!EvaluateInteger(E->getInit(i), sInt, Info)) + return APValue(); + } else { + sInt = Info.Ctx.MakeIntValue(0, EltTy); + } + Elements.push_back(APValue(sInt)); + } else { + llvm::APFloat f(0.0); + if (i < NumInits) { + if (!EvaluateFloat(E->getInit(i), f, Info)) + return APValue(); + } else { + f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)); + } + Elements.push_back(APValue(f)); + } + } + return APValue(&Elements[0], Elements.size()); +} + +APValue +VectorExprEvaluator::GetZeroVector(QualType T) { + const VectorType *VT = T->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))); + + llvm::SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement); + return APValue(&Elements[0], Elements.size()); +} + +APValue VectorExprEvaluator::VisitConditionalOperator(const ConditionalOperator *E) { + bool BoolResult; + if (!HandleConversionToBool(E->getCond(), BoolResult, Info)) + return APValue(); + + Expr* EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr(); + + APValue Result; + if (EvaluateVector(EvalExpr, Result, Info)) + return Result; + return APValue(); +} + +APValue VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { + if (!E->getSubExpr()->isEvaluatable(Info.Ctx)) + Info.EvalResult.HasSideEffects = true; + return GetZeroVector(E->getType()); +} + +//===----------------------------------------------------------------------===// +// Integer Evaluation +//===----------------------------------------------------------------------===// + +namespace { +class IntExprEvaluator + : public StmtVisitor<IntExprEvaluator, bool> { + EvalInfo &Info; + APValue &Result; +public: + IntExprEvaluator(EvalInfo &info, APValue &result) + : Info(info), Result(result) {} + + bool Success(const llvm::APSInt &SI, const Expr *E) { + assert(E->getType()->isIntegralType() && "Invalid evaluation result."); + assert(SI.isSigned() == E->getType()->isSignedIntegerType() && + "Invalid evaluation result."); + assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && + "Invalid evaluation result."); + Result = APValue(SI); + return true; + } + + bool Success(const llvm::APInt &I, const Expr *E) { + assert(E->getType()->isIntegralType() && "Invalid evaluation result."); + assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && + "Invalid evaluation result."); + Result = APValue(APSInt(I)); + Result.getInt().setIsUnsigned(E->getType()->isUnsignedIntegerType()); + return true; + } + + bool Success(uint64_t Value, const Expr *E) { + assert(E->getType()->isIntegralType() && "Invalid evaluation result."); + Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType())); + return true; + } + + bool Error(SourceLocation L, diag::kind D, const Expr *E) { + // Take the first error. + if (Info.EvalResult.Diag == 0) { + Info.EvalResult.DiagLoc = L; + Info.EvalResult.Diag = D; + Info.EvalResult.DiagExpr = E; + } + return false; + } + + //===--------------------------------------------------------------------===// + // Visitor Methods + //===--------------------------------------------------------------------===// + + bool VisitStmt(Stmt *) { + assert(0 && "This should be called on integers, stmts are not integers"); + return false; + } + + bool VisitExpr(Expr *E) { + return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E); + } + + bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + + bool VisitIntegerLiteral(const IntegerLiteral *E) { + return Success(E->getValue(), E); + } + bool VisitCharacterLiteral(const CharacterLiteral *E) { + return Success(E->getValue(), E); + } + bool VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) { + // Per gcc docs "this built-in function ignores top level + // qualifiers". We need to use the canonical version to properly + // be able to strip CRV qualifiers from the type. + QualType T0 = Info.Ctx.getCanonicalType(E->getArgType1()); + QualType T1 = Info.Ctx.getCanonicalType(E->getArgType2()); + return Success(Info.Ctx.typesAreCompatible(T0.getUnqualifiedType(), + T1.getUnqualifiedType()), + E); + } + + bool CheckReferencedDecl(const Expr *E, const Decl *D); + bool VisitDeclRefExpr(const DeclRefExpr *E) { + return CheckReferencedDecl(E, E->getDecl()); + } + bool VisitMemberExpr(const MemberExpr *E) { + if (CheckReferencedDecl(E, E->getMemberDecl())) { + // Conservatively assume a MemberExpr will have side-effects + Info.EvalResult.HasSideEffects = true; + return true; + } + return false; + } + + bool VisitCallExpr(CallExpr *E); + bool VisitBinaryOperator(const BinaryOperator *E); + bool VisitOffsetOfExpr(const OffsetOfExpr *E); + bool VisitUnaryOperator(const UnaryOperator *E); + bool VisitConditionalOperator(const ConditionalOperator *E); + + bool VisitCastExpr(CastExpr* E); + bool VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E); + + bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { + return Success(E->getValue(), E); + } + + bool VisitGNUNullExpr(const GNUNullExpr *E) { + return Success(0, E); + } + + bool VisitCXXZeroInitValueExpr(const CXXZeroInitValueExpr *E) { + return Success(0, E); + } + + bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { + return Success(0, E); + } + + bool VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr *E) { + return Success(E->EvaluateTrait(Info.Ctx), E); + } + + bool VisitChooseExpr(const ChooseExpr *E) { + return Visit(E->getChosenSubExpr(Info.Ctx)); + } + + bool VisitUnaryReal(const UnaryOperator *E); + bool VisitUnaryImag(const UnaryOperator *E); + +private: + CharUnits GetAlignOfExpr(const Expr *E); + CharUnits GetAlignOfType(QualType T); + static QualType GetObjectType(const Expr *E); + bool TryEvaluateBuiltinObjectSize(CallExpr *E); + // FIXME: Missing: array subscript of vector, member of vector +}; +} // end anonymous namespace + +static bool EvaluateIntegerOrLValue(const Expr* E, APValue &Result, EvalInfo &Info) { + assert(E->getType()->isIntegralType()); + return IntExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E)); +} + +static bool EvaluateInteger(const Expr* E, APSInt &Result, EvalInfo &Info) { + assert(E->getType()->isIntegralType()); + + APValue Val; + if (!EvaluateIntegerOrLValue(E, Val, Info) || !Val.isInt()) + return false; + Result = Val.getInt(); + return true; +} + +bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) { + // Enums are integer constant exprs. + if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) + return Success(ECD->getInitVal(), E); + + // In C++, const, non-volatile integers initialized with ICEs are ICEs. + // In C, they can also be folded, although they are not ICEs. + if (Info.Ctx.getCanonicalType(E->getType()).getCVRQualifiers() + == Qualifiers::Const) { + + if (isa<ParmVarDecl>(D)) + return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E); + + if (const VarDecl *VD = dyn_cast<VarDecl>(D)) { + if (const Expr *Init = VD->getAnyInitializer()) { + if (APValue *V = VD->getEvaluatedValue()) { + if (V->isInt()) + return Success(V->getInt(), E); + return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E); + } + + if (VD->isEvaluatingValue()) + return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E); + + VD->setEvaluatingValue(); + + if (Visit(const_cast<Expr*>(Init))) { + // Cache the evaluated value in the variable declaration. + VD->setEvaluatedValue(Result); + return true; + } + + VD->setEvaluatedValue(APValue()); + return false; + } + } + } + + // Otherwise, random variable references are not constants. + return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E); +} + +/// 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? + assert(0 && "CallExpr::isBuiltinClassifyType(): unimplemented type"); + return -1; +} + +/// Retrieves the "underlying object type" of the given expression, +/// as used by __builtin_object_size. +QualType IntExprEvaluator::GetObjectType(const Expr *E) { + if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { + if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) + return VD->getType(); + } else if (isa<CompoundLiteralExpr>(E)) { + return E->getType(); + } + + return QualType(); +} + +bool IntExprEvaluator::TryEvaluateBuiltinObjectSize(CallExpr *E) { + // TODO: Perhaps we should let LLVM lower this? + LValue Base; + if (!EvaluatePointer(E->getArg(0), Base, Info)) + return false; + + // If we can prove the base is null, lower to zero now. + const Expr *LVBase = Base.getLValueBase(); + if (!LVBase) return Success(0, E); + + QualType T = GetObjectType(LVBase); + if (T.isNull() || + T->isIncompleteType() || + !T->isObjectType() || + T->isVariablyModifiedType() || + T->isDependentType()) + return false; + + CharUnits Size = Info.Ctx.getTypeSizeInChars(T); + CharUnits Offset = Base.getLValueOffset(); + + if (!Offset.isNegative() && Offset <= Size) + Size -= Offset; + else + Size = CharUnits::Zero(); + return Success(Size.getQuantity(), E); +} + +bool IntExprEvaluator::VisitCallExpr(CallExpr *E) { + switch (E->isBuiltinCall(Info.Ctx)) { + default: + return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, 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 lower it to unknown now. + if (E->getArg(0)->HasSideEffects(Info.Ctx)) { + if (E->getArg(1)->EvaluateAsInt(Info.Ctx).getZExtValue() <= 1) + return Success(-1ULL, E); + return Success(0, E); + } + + return Error(E->getLocStart(), diag::note_invalid_subexpr_in_ice, E); + } + + case Builtin::BI__builtin_classify_type: + return Success(EvaluateBuiltinClassifyType(E), E); + + case Builtin::BI__builtin_constant_p: + // __builtin_constant_p always has one operand: it returns true if that + // operand can be folded, false otherwise. + return Success(E->getArg(0)->isEvaluatable(Info.Ctx), E); + + case Builtin::BI__builtin_eh_return_data_regno: { + int Operand = E->getArg(0)->EvaluateAsInt(Info.Ctx).getZExtValue(); + Operand = Info.Ctx.Target.getEHDataRegisterNumber(Operand); + return Success(Operand, E); + } + + case Builtin::BI__builtin_expect: + return Visit(E->getArg(0)); + } +} + +bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { + if (E->getOpcode() == BinaryOperator::Comma) { + if (!Visit(E->getRHS())) + return false; + + // If we can't evaluate the LHS, it might have side effects; + // conservatively mark it. + if (!E->getLHS()->isEvaluatable(Info.Ctx)) + Info.EvalResult.HasSideEffects = true; + + return true; + } + + if (E->isLogicalOp()) { + // These need to be handled specially because the operands aren't + // necessarily integral + bool lhsResult, rhsResult; + + if (HandleConversionToBool(E->getLHS(), lhsResult, Info)) { + // 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 (lhsResult == (E->getOpcode() == BinaryOperator::LOr)) + return Success(lhsResult, E); + + if (HandleConversionToBool(E->getRHS(), rhsResult, Info)) { + if (E->getOpcode() == BinaryOperator::LOr) + return Success(lhsResult || rhsResult, E); + else + return Success(lhsResult && rhsResult, E); + } + } else { + if (HandleConversionToBool(E->getRHS(), rhsResult, Info)) { + // 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() == BinaryOperator::LOr) || + !rhsResult == (E->getOpcode() == BinaryOperator::LAnd)) { + // Since we weren't able to evaluate the left hand side, it + // must have had side effects. + Info.EvalResult.HasSideEffects = true; + + return Success(rhsResult, E); + } + } + } + + return false; + } + + QualType LHSTy = E->getLHS()->getType(); + QualType RHSTy = E->getRHS()->getType(); + + if (LHSTy->isAnyComplexType()) { + assert(RHSTy->isAnyComplexType() && "Invalid comparison"); + ComplexValue LHS, RHS; + + if (!EvaluateComplex(E->getLHS(), LHS, Info)) + return false; + + if (!EvaluateComplex(E->getRHS(), RHS, Info)) + 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() == BinaryOperator::EQ) + return Success((CR_r == APFloat::cmpEqual && + CR_i == APFloat::cmpEqual), E); + else { + assert(E->getOpcode() == BinaryOperator::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() == BinaryOperator::EQ) + return Success((LHS.getComplexIntReal() == RHS.getComplexIntReal() && + LHS.getComplexIntImag() == RHS.getComplexIntImag()), E); + else { + assert(E->getOpcode() == BinaryOperator::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); + + if (!EvaluateFloat(E->getRHS(), RHS, Info)) + return false; + + if (!EvaluateFloat(E->getLHS(), LHS, Info)) + return false; + + APFloat::cmpResult CR = LHS.compare(RHS); + + switch (E->getOpcode()) { + default: + assert(0 && "Invalid binary operator!"); + case BinaryOperator::LT: + return Success(CR == APFloat::cmpLessThan, E); + case BinaryOperator::GT: + return Success(CR == APFloat::cmpGreaterThan, E); + case BinaryOperator::LE: + return Success(CR == APFloat::cmpLessThan || CR == APFloat::cmpEqual, E); + case BinaryOperator::GE: + return Success(CR == APFloat::cmpGreaterThan || CR == APFloat::cmpEqual, + E); + case BinaryOperator::EQ: + return Success(CR == APFloat::cmpEqual, E); + case BinaryOperator::NE: + return Success(CR == APFloat::cmpGreaterThan + || CR == APFloat::cmpLessThan + || CR == APFloat::cmpUnordered, E); + } + } + + if (LHSTy->isPointerType() && RHSTy->isPointerType()) { + if (E->getOpcode() == BinaryOperator::Sub || E->isEqualityOp()) { + LValue LHSValue; + if (!EvaluatePointer(E->getLHS(), LHSValue, Info)) + return false; + + LValue RHSValue; + if (!EvaluatePointer(E->getRHS(), RHSValue, Info)) + return false; + + // Reject any bases from the normal codepath; we special-case comparisons + // to null. + if (LHSValue.getLValueBase()) { + if (!E->isEqualityOp()) + return false; + if (RHSValue.getLValueBase() || !RHSValue.getLValueOffset().isZero()) + return false; + bool bres; + if (!EvalPointerValueAsBool(LHSValue, bres)) + return false; + return Success(bres ^ (E->getOpcode() == BinaryOperator::EQ), E); + } else if (RHSValue.getLValueBase()) { + if (!E->isEqualityOp()) + return false; + if (LHSValue.getLValueBase() || !LHSValue.getLValueOffset().isZero()) + return false; + bool bres; + if (!EvalPointerValueAsBool(RHSValue, bres)) + return false; + return Success(bres ^ (E->getOpcode() == BinaryOperator::EQ), E); + } + + if (E->getOpcode() == BinaryOperator::Sub) { + QualType Type = E->getLHS()->getType(); + QualType ElementType = Type->getAs<PointerType>()->getPointeeType(); + + CharUnits ElementSize = CharUnits::One(); + if (!ElementType->isVoidType() && !ElementType->isFunctionType()) + ElementSize = Info.Ctx.getTypeSizeInChars(ElementType); + + CharUnits Diff = LHSValue.getLValueOffset() - + RHSValue.getLValueOffset(); + return Success(Diff / ElementSize, E); + } + bool Result; + if (E->getOpcode() == BinaryOperator::EQ) { + Result = LHSValue.getLValueOffset() == RHSValue.getLValueOffset(); + } else { + Result = LHSValue.getLValueOffset() != RHSValue.getLValueOffset(); + } + return Success(Result, E); + } + } + if (!LHSTy->isIntegralType() || + !RHSTy->isIntegralType()) { + // We can't continue from here for non-integral types, and they + // could potentially confuse the following operations. + return false; + } + + // The LHS of a constant expr is always evaluated and needed. + if (!Visit(E->getLHS())) + return false; // error in subexpression. + + APValue RHSVal; + if (!EvaluateIntegerOrLValue(E->getRHS(), RHSVal, Info)) + return false; + + // Handle cases like (unsigned long)&a + 4. + if (E->isAdditiveOp() && Result.isLValue() && RHSVal.isInt()) { + CharUnits Offset = Result.getLValueOffset(); + CharUnits AdditionalOffset = CharUnits::fromQuantity( + RHSVal.getInt().getZExtValue()); + if (E->getOpcode() == BinaryOperator::Add) + Offset += AdditionalOffset; + else + Offset -= AdditionalOffset; + Result = APValue(Result.getLValueBase(), Offset); + return true; + } + + // Handle cases like 4 + (unsigned long)&a + if (E->getOpcode() == BinaryOperator::Add && + RHSVal.isLValue() && Result.isInt()) { + CharUnits Offset = RHSVal.getLValueOffset(); + Offset += CharUnits::fromQuantity(Result.getInt().getZExtValue()); + Result = APValue(RHSVal.getLValueBase(), Offset); + return true; + } + + // All the following cases expect both operands to be an integer + if (!Result.isInt() || !RHSVal.isInt()) + return false; + + APSInt& RHS = RHSVal.getInt(); + + switch (E->getOpcode()) { + default: + return Error(E->getOperatorLoc(), diag::note_invalid_subexpr_in_ice, E); + case BinaryOperator::Mul: return Success(Result.getInt() * RHS, E); + case BinaryOperator::Add: return Success(Result.getInt() + RHS, E); + case BinaryOperator::Sub: return Success(Result.getInt() - RHS, E); + case BinaryOperator::And: return Success(Result.getInt() & RHS, E); + case BinaryOperator::Xor: return Success(Result.getInt() ^ RHS, E); + case BinaryOperator::Or: return Success(Result.getInt() | RHS, E); + case BinaryOperator::Div: + if (RHS == 0) + return Error(E->getOperatorLoc(), diag::note_expr_divide_by_zero, E); + return Success(Result.getInt() / RHS, E); + case BinaryOperator::Rem: + if (RHS == 0) + return Error(E->getOperatorLoc(), diag::note_expr_divide_by_zero, E); + return Success(Result.getInt() % RHS, E); + case BinaryOperator::Shl: { + // FIXME: Warn about out of range shift amounts! + unsigned SA = + (unsigned) RHS.getLimitedValue(Result.getInt().getBitWidth()-1); + return Success(Result.getInt() << SA, E); + } + case BinaryOperator::Shr: { + unsigned SA = + (unsigned) RHS.getLimitedValue(Result.getInt().getBitWidth()-1); + return Success(Result.getInt() >> SA, E); + } + + case BinaryOperator::LT: return Success(Result.getInt() < RHS, E); + case BinaryOperator::GT: return Success(Result.getInt() > RHS, E); + case BinaryOperator::LE: return Success(Result.getInt() <= RHS, E); + case BinaryOperator::GE: return Success(Result.getInt() >= RHS, E); + case BinaryOperator::EQ: return Success(Result.getInt() == RHS, E); + case BinaryOperator::NE: return Success(Result.getInt() != RHS, E); + } +} + +bool IntExprEvaluator::VisitConditionalOperator(const ConditionalOperator *E) { + bool Cond; + if (!HandleConversionToBool(E->getCond(), Cond, Info)) + return false; + + return Visit(Cond ? E->getTrueExpr() : E->getFalseExpr()); +} + +CharUnits IntExprEvaluator::GetAlignOfType(QualType T) { + // C++ [expr.sizeof]p2: "When applied to a reference or a reference type, + // the result is the size of the referenced type." + // 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(); + + // Get information about the alignment. + unsigned CharSize = Info.Ctx.Target.getCharWidth(); + + // __alignof is defined to return the preferred alignment. + return CharUnits::fromQuantity( + Info.Ctx.getPreferredTypeAlign(T.getTypePtr()) / CharSize); +} + +CharUnits IntExprEvaluator::GetAlignOfExpr(const Expr *E) { + E = E->IgnoreParens(); + + // 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()); +} + + +/// VisitSizeAlignOfExpr - Evaluate a sizeof or alignof with a result as the +/// expression's type. +bool IntExprEvaluator::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) { + // Handle alignof separately. + if (!E->isSizeOf()) { + if (E->isArgumentType()) + return Success(GetAlignOfType(E->getArgumentType()).getQuantity(), E); + else + return Success(GetAlignOfExpr(E->getArgumentExpr()).getQuantity(), E); + } + + 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." + // 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 = SrcTy->getAs<ReferenceType>()) + SrcTy = Ref->getPointeeType(); + + // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc + // extension. + if (SrcTy->isVoidType() || SrcTy->isFunctionType()) + return Success(1, E); + + // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2. + if (!SrcTy->isConstantSizeType()) + return false; + + // Get information about the size. + return Success(Info.Ctx.getTypeSizeInChars(SrcTy).getQuantity(), E); +} + +bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *E) { + CharUnits Result; + unsigned n = E->getNumComponents(); + OffsetOfExpr* OOE = const_cast<OffsetOfExpr*>(E); + if (n == 0) + return false; + QualType CurrentType = E->getTypeSourceInfo()->getType(); + for (unsigned i = 0; i != n; ++i) { + OffsetOfExpr::OffsetOfNode ON = OOE->getComponent(i); + switch (ON.getKind()) { + case OffsetOfExpr::OffsetOfNode::Array: { + 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 false; + 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 false; + RecordDecl *RD = RT->getDecl(); + const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); + unsigned i = 0; + // FIXME: It would be nice if we didn't have to loop here! + for (RecordDecl::field_iterator Field = RD->field_begin(), + FieldEnd = RD->field_end(); + Field != FieldEnd; (void)++Field, ++i) { + if (*Field == MemberDecl) + break; + } + assert(i < RL.getFieldCount() && "offsetof field in wrong type"); + Result += CharUnits::fromQuantity( + RL.getFieldOffset(i) / Info.Ctx.getCharWidth()); + CurrentType = MemberDecl->getType().getNonReferenceType(); + break; + } + + case OffsetOfExpr::OffsetOfNode::Identifier: + llvm_unreachable("dependent __builtin_offsetof"); + return false; + + case OffsetOfExpr::OffsetOfNode::Base: { + CXXBaseSpecifier *BaseSpec = ON.getBase(); + if (BaseSpec->isVirtual()) + return false; + + // Find the layout of the class whose base we are looking into. + const RecordType *RT = CurrentType->getAs<RecordType>(); + if (!RT) + return false; + RecordDecl *RD = RT->getDecl(); + const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); + + // Find the base class itself. + CurrentType = BaseSpec->getType(); + const RecordType *BaseRT = CurrentType->getAs<RecordType>(); + if (!BaseRT) + return false; + + // Add the offset to the base. + Result += CharUnits::fromQuantity( + RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl())) + / Info.Ctx.getCharWidth()); + break; + } + } + } + return Success(Result.getQuantity(), E); +} + +bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { + // Special case unary operators that do not need their subexpression + // evaluated. offsetof/sizeof/alignof are all special. + if (E->isOffsetOfOp()) { + // The AST for offsetof is defined in such a way that we can just + // directly Evaluate it as an l-value. + LValue LV; + if (!EvaluateLValue(E->getSubExpr(), LV, Info)) + return false; + if (LV.getLValueBase()) + return false; + return Success(LV.getLValueOffset().getQuantity(), E); + } + + if (E->getOpcode() == UnaryOperator::LNot) { + // LNot's operand isn't necessarily an integer, so we handle it specially. + bool bres; + if (!HandleConversionToBool(E->getSubExpr(), bres, Info)) + return false; + return Success(!bres, E); + } + + // Only handle integral operations... + if (!E->getSubExpr()->getType()->isIntegralType()) + return false; + + // Get the operand value into 'Result'. + if (!Visit(E->getSubExpr())) + return false; + + switch (E->getOpcode()) { + default: + // Address, indirect, pre/post inc/dec, etc are not valid constant exprs. + // See C99 6.6p3. + return Error(E->getOperatorLoc(), diag::note_invalid_subexpr_in_ice, E); + case UnaryOperator::Extension: + // FIXME: Should extension allow i-c-e extension expressions in its scope? + // If so, we could clear the diagnostic ID. + return true; + case UnaryOperator::Plus: + // The result is always just the subexpr. + return true; + case UnaryOperator::Minus: + if (!Result.isInt()) return false; + return Success(-Result.getInt(), E); + case UnaryOperator::Not: + if (!Result.isInt()) return false; + return Success(~Result.getInt(), E); + } +} + +/// HandleCast - This is used to evaluate implicit or explicit casts where the +/// result type is integer. +bool IntExprEvaluator::VisitCastExpr(CastExpr *E) { + Expr *SubExpr = E->getSubExpr(); + QualType DestType = E->getType(); + QualType SrcType = SubExpr->getType(); + + if (DestType->isBooleanType()) { + bool BoolResult; + if (!HandleConversionToBool(SubExpr, BoolResult, Info)) + return false; + return Success(BoolResult, E); + } + + // Handle simple integer->integer casts. + if (SrcType->isIntegralType()) { + if (!Visit(SubExpr)) + return false; + + if (!Result.isInt()) { + // Only allow casts of lvalues if they are lossless. + return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType); + } + + return Success(HandleIntToIntCast(DestType, SrcType, + Result.getInt(), Info.Ctx), E); + } + + // FIXME: Clean this up! + if (SrcType->isPointerType()) { + LValue LV; + if (!EvaluatePointer(SubExpr, LV, Info)) + return false; + + if (LV.getLValueBase()) { + // Only allow based lvalue casts if they are lossless. + if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType)) + return false; + + LV.moveInto(Result); + return true; + } + + APSInt AsInt = Info.Ctx.MakeIntValue(LV.getLValueOffset().getQuantity(), + SrcType); + return Success(HandleIntToIntCast(DestType, SrcType, AsInt, Info.Ctx), E); + } + + if (SrcType->isArrayType() || SrcType->isFunctionType()) { + // This handles double-conversion cases, where there's both + // an l-value promotion and an implicit conversion to int. + LValue LV; + if (!EvaluateLValue(SubExpr, LV, Info)) + return false; + + if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(Info.Ctx.VoidPtrTy)) + return false; + + LV.moveInto(Result); + return true; + } + + if (SrcType->isAnyComplexType()) { + ComplexValue C; + if (!EvaluateComplex(SubExpr, C, Info)) + return false; + if (C.isComplexFloat()) + return Success(HandleFloatToIntCast(DestType, SrcType, + C.getComplexFloatReal(), Info.Ctx), + E); + else + return Success(HandleIntToIntCast(DestType, SrcType, + C.getComplexIntReal(), Info.Ctx), E); + } + // FIXME: Handle vectors + + if (!SrcType->isRealFloatingType()) + return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, E); + + APFloat F(0.0); + if (!EvaluateFloat(SubExpr, F, Info)) + return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, E); + + return Success(HandleFloatToIntCast(DestType, SrcType, F, Info.Ctx), E); +} + +bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { + if (E->getSubExpr()->getType()->isAnyComplexType()) { + ComplexValue LV; + if (!EvaluateComplex(E->getSubExpr(), LV, Info) || !LV.isComplexInt()) + return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, 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) || !LV.isComplexInt()) + return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, E); + return Success(LV.getComplexIntImag(), E); + } + + if (!E->getSubExpr()->isEvaluatable(Info.Ctx)) + Info.EvalResult.HasSideEffects = true; + return Success(0, E); +} + +//===----------------------------------------------------------------------===// +// Float Evaluation +//===----------------------------------------------------------------------===// + +namespace { +class FloatExprEvaluator + : public StmtVisitor<FloatExprEvaluator, bool> { + EvalInfo &Info; + APFloat &Result; +public: + FloatExprEvaluator(EvalInfo &info, APFloat &result) + : Info(info), Result(result) {} + + bool VisitStmt(Stmt *S) { + return false; + } + + bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + bool VisitCallExpr(const CallExpr *E); + + bool VisitUnaryOperator(const UnaryOperator *E); + bool VisitBinaryOperator(const BinaryOperator *E); + bool VisitFloatingLiteral(const FloatingLiteral *E); + bool VisitCastExpr(CastExpr *E); + bool VisitCXXZeroInitValueExpr(CXXZeroInitValueExpr *E); + bool VisitConditionalOperator(ConditionalOperator *E); + + bool VisitChooseExpr(const ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + bool VisitUnaryExtension(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + bool VisitUnaryReal(const UnaryOperator *E); + bool VisitUnaryImag(const UnaryOperator *E); + + // FIXME: Missing: array subscript of vector, member of vector, + // ImplicitValueInitExpr +}; +} // end anonymous namespace + +static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) { + assert(E->getType()->isRealFloatingType()); + return FloatExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E)); +} + +static bool TryEvaluateBuiltinNaN(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(Info.Ctx)) { + default: return false; + 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: + return TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), + true, Result); + + 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. + return TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), + false, Result); + + 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; + + 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) { + ComplexValue CV; + if (!EvaluateComplex(E->getSubExpr(), CV, Info)) + return false; + Result = CV.FloatReal; + return true; +} + +bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { + ComplexValue CV; + if (!EvaluateComplex(E->getSubExpr(), CV, Info)) + return false; + Result = CV.FloatImag; + return true; +} + +bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { + if (E->getOpcode() == UnaryOperator::Deref) + return false; + + if (!EvaluateFloat(E->getSubExpr(), Result, Info)) + return false; + + switch (E->getOpcode()) { + default: return false; + case UnaryOperator::Plus: + return true; + case UnaryOperator::Minus: + Result.changeSign(); + return true; + } +} + +bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { + if (E->getOpcode() == BinaryOperator::Comma) { + if (!EvaluateFloat(E->getRHS(), Result, Info)) + return false; + + // If we can't evaluate the LHS, it might have side effects; + // conservatively mark it. + if (!E->getLHS()->isEvaluatable(Info.Ctx)) + Info.EvalResult.HasSideEffects = true; + + return true; + } + + // FIXME: Diagnostics? I really don't understand how the warnings + // and errors are supposed to work. + APFloat RHS(0.0); + if (!EvaluateFloat(E->getLHS(), Result, Info)) + return false; + if (!EvaluateFloat(E->getRHS(), RHS, Info)) + return false; + + switch (E->getOpcode()) { + default: return false; + case BinaryOperator::Mul: + Result.multiply(RHS, APFloat::rmNearestTiesToEven); + return true; + case BinaryOperator::Add: + Result.add(RHS, APFloat::rmNearestTiesToEven); + return true; + case BinaryOperator::Sub: + Result.subtract(RHS, APFloat::rmNearestTiesToEven); + return true; + case BinaryOperator::Div: + Result.divide(RHS, APFloat::rmNearestTiesToEven); + return true; + } +} + +bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) { + Result = E->getValue(); + return true; +} + +bool FloatExprEvaluator::VisitCastExpr(CastExpr *E) { + Expr* SubExpr = E->getSubExpr(); + + if (SubExpr->getType()->isIntegralType()) { + APSInt IntResult; + if (!EvaluateInteger(SubExpr, IntResult, Info)) + return false; + Result = HandleIntToFloatCast(E->getType(), SubExpr->getType(), + IntResult, Info.Ctx); + return true; + } + if (SubExpr->getType()->isRealFloatingType()) { + if (!Visit(SubExpr)) + return false; + Result = HandleFloatToFloatCast(E->getType(), SubExpr->getType(), + Result, Info.Ctx); + return true; + } + // FIXME: Handle complex types + + return false; +} + +bool FloatExprEvaluator::VisitCXXZeroInitValueExpr(CXXZeroInitValueExpr *E) { + Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType())); + return true; +} + +bool FloatExprEvaluator::VisitConditionalOperator(ConditionalOperator *E) { + bool Cond; + if (!HandleConversionToBool(E->getCond(), Cond, Info)) + return false; + + return Visit(Cond ? E->getTrueExpr() : E->getFalseExpr()); +} + +//===----------------------------------------------------------------------===// +// Complex Evaluation (for float and integer) +//===----------------------------------------------------------------------===// + +namespace { +class ComplexExprEvaluator + : public StmtVisitor<ComplexExprEvaluator, bool> { + EvalInfo &Info; + ComplexValue &Result; + +public: + ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result) + : Info(info), Result(Result) {} + + //===--------------------------------------------------------------------===// + // Visitor Methods + //===--------------------------------------------------------------------===// + + bool VisitStmt(Stmt *S) { + return false; + } + + bool VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + + bool VisitImaginaryLiteral(ImaginaryLiteral *E) { + 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 VisitCastExpr(CastExpr *E) { + Expr* SubExpr = E->getSubExpr(); + QualType EltType = E->getType()->getAs<ComplexType>()->getElementType(); + QualType SubType = SubExpr->getType(); + + if (SubType->isRealFloatingType()) { + APFloat &Real = Result.FloatReal; + if (!EvaluateFloat(SubExpr, Real, Info)) + return false; + + if (EltType->isRealFloatingType()) { + Result.makeComplexFloat(); + Real = HandleFloatToFloatCast(EltType, SubType, Real, Info.Ctx); + Result.FloatImag = APFloat(Real.getSemantics()); + return true; + } else { + Result.makeComplexInt(); + Result.IntReal = HandleFloatToIntCast(EltType, SubType, Real, Info.Ctx); + Result.IntImag = APSInt(Result.IntReal.getBitWidth(), + !Result.IntReal.isSigned()); + return true; + } + } else if (SubType->isIntegerType()) { + APSInt &Real = Result.IntReal; + if (!EvaluateInteger(SubExpr, Real, Info)) + return false; + + if (EltType->isRealFloatingType()) { + Result.makeComplexFloat(); + Result.FloatReal + = HandleIntToFloatCast(EltType, SubType, Real, Info.Ctx); + Result.FloatImag = APFloat(Result.FloatReal.getSemantics()); + return true; + } else { + Result.makeComplexInt(); + Real = HandleIntToIntCast(EltType, SubType, Real, Info.Ctx); + Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned()); + return true; + } + } else if (const ComplexType *CT = SubType->getAs<ComplexType>()) { + if (!Visit(SubExpr)) + return false; + + QualType SrcType = CT->getElementType(); + + if (Result.isComplexFloat()) { + if (EltType->isRealFloatingType()) { + Result.makeComplexFloat(); + Result.FloatReal = HandleFloatToFloatCast(EltType, SrcType, + Result.FloatReal, + Info.Ctx); + Result.FloatImag = HandleFloatToFloatCast(EltType, SrcType, + Result.FloatImag, + Info.Ctx); + return true; + } else { + Result.makeComplexInt(); + Result.IntReal = HandleFloatToIntCast(EltType, SrcType, + Result.FloatReal, + Info.Ctx); + Result.IntImag = HandleFloatToIntCast(EltType, SrcType, + Result.FloatImag, + Info.Ctx); + return true; + } + } else { + assert(Result.isComplexInt() && "Invalid evaluate result."); + if (EltType->isRealFloatingType()) { + Result.makeComplexFloat(); + Result.FloatReal = HandleIntToFloatCast(EltType, SrcType, + Result.IntReal, + Info.Ctx); + Result.FloatImag = HandleIntToFloatCast(EltType, SrcType, + Result.IntImag, + Info.Ctx); + return true; + } else { + Result.makeComplexInt(); + Result.IntReal = HandleIntToIntCast(EltType, SrcType, + Result.IntReal, + Info.Ctx); + Result.IntImag = HandleIntToIntCast(EltType, SrcType, + Result.IntImag, + Info.Ctx); + return true; + } + } + } + + // FIXME: Handle more casts. + return false; + } + + bool VisitBinaryOperator(const BinaryOperator *E); + bool VisitChooseExpr(const ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + bool VisitUnaryExtension(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + // FIXME Missing: unary +/-/~, binary div, ImplicitValueInitExpr, + // conditional ?:, comma +}; +} // end anonymous namespace + +static bool EvaluateComplex(const Expr *E, ComplexValue &Result, + EvalInfo &Info) { + assert(E->getType()->isAnyComplexType()); + return ComplexExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E)); +} + +bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { + if (!Visit(E->getLHS())) + return false; + + ComplexValue RHS; + if (!EvaluateComplex(E->getRHS(), RHS, Info)) + return false; + + assert(Result.isComplexFloat() == RHS.isComplexFloat() && + "Invalid operands to binary operator."); + switch (E->getOpcode()) { + default: return false; + case BinaryOperator::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 BinaryOperator::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 BinaryOperator::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; + } + + return true; +} + +//===----------------------------------------------------------------------===// +// Top level Expr::Evaluate method. +//===----------------------------------------------------------------------===// + +/// Evaluate - 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. +bool Expr::Evaluate(EvalResult &Result, ASTContext &Ctx) const { + const Expr *E = this; + EvalInfo Info(Ctx, Result); + if (E->getType()->isVectorType()) { + if (!EvaluateVector(E, Info.EvalResult.Val, Info)) + return false; + } else if (E->getType()->isIntegerType()) { + if (!IntExprEvaluator(Info, Info.EvalResult.Val).Visit(const_cast<Expr*>(E))) + return false; + } else if (E->getType()->hasPointerRepresentation()) { + LValue LV; + if (!EvaluatePointer(E, LV, Info)) + return false; + if (!IsGlobalLValue(LV.Base)) + return false; + LV.moveInto(Info.EvalResult.Val); + } else if (E->getType()->isRealFloatingType()) { + llvm::APFloat F(0.0); + if (!EvaluateFloat(E, F, Info)) + return false; + + Info.EvalResult.Val = APValue(F); + } else if (E->getType()->isAnyComplexType()) { + ComplexValue C; + if (!EvaluateComplex(E, C, Info)) + return false; + C.moveInto(Info.EvalResult.Val); + } else + return false; + + return true; +} + +bool Expr::EvaluateAsBooleanCondition(bool &Result, ASTContext &Ctx) const { + EvalResult Scratch; + EvalInfo Info(Ctx, Scratch); + + return HandleConversionToBool(this, Result, Info); +} + +bool Expr::EvaluateAsLValue(EvalResult &Result, ASTContext &Ctx) const { + EvalInfo Info(Ctx, Result); + + LValue LV; + if (EvaluateLValue(this, LV, Info) && + !Result.HasSideEffects && + IsGlobalLValue(LV.Base)) { + LV.moveInto(Result.Val); + return true; + } + return false; +} + +bool Expr::EvaluateAsAnyLValue(EvalResult &Result, ASTContext &Ctx) const { + EvalInfo Info(Ctx, Result); + + LValue LV; + if (EvaluateLValue(this, LV, Info)) { + LV.moveInto(Result.Val); + return true; + } + return false; +} + +/// isEvaluatable - Call Evaluate to see if this expression can be constant +/// folded, but discard the result. +bool Expr::isEvaluatable(ASTContext &Ctx) const { + EvalResult Result; + return Evaluate(Result, Ctx) && !Result.HasSideEffects; +} + +bool Expr::HasSideEffects(ASTContext &Ctx) const { + Expr::EvalResult Result; + EvalInfo Info(Ctx, Result); + return HasSideEffect(Info).Visit(const_cast<Expr*>(this)); +} + +APSInt Expr::EvaluateAsInt(ASTContext &Ctx) const { + EvalResult EvalResult; + bool Result = Evaluate(EvalResult, Ctx); + Result = Result; + assert(Result && "Could not evaluate expression"); + assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer"); + + return EvalResult.Val.getInt(); +} + + 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 +/// +/// FIXME: Handle offsetof. Two things to do: Handle GCC's __builtin_offsetof +/// to support gcc 4.0+ and handle the idiom GCC recognizes with a null pointer +/// cast+dereference. + +// CheckICE - This function does the fundamental ICE checking: the returned +// ICEDiag contains a Val of 0, 1, or 2, and a possibly null SourceLocation. +// 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. +// +// Meanings of Val: +// 0: This expression is an ICE if it can be evaluated by Evaluate. +// 1: 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. +// 2: This expression is not an ICE, and is not a legal subexpression for one. + +struct ICEDiag { + unsigned Val; + SourceLocation Loc; + + public: + ICEDiag(unsigned v, SourceLocation l) : Val(v), Loc(l) {} + ICEDiag() : Val(0) {} +}; + +ICEDiag NoDiag() { return ICEDiag(); } + +static ICEDiag CheckEvalInICE(const Expr* E, ASTContext &Ctx) { + Expr::EvalResult EVResult; + if (!E->Evaluate(EVResult, Ctx) || EVResult.HasSideEffects || + !EVResult.Val.isInt()) { + return ICEDiag(2, E->getLocStart()); + } + return NoDiag(); +} + +static ICEDiag CheckICE(const Expr* E, ASTContext &Ctx) { + assert(!E->isValueDependent() && "Should not see value dependent exprs!"); + if (!E->getType()->isIntegralType()) { + return ICEDiag(2, E->getLocStart()); + } + + switch (E->getStmtClass()) { +#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::InitListExprClass: + case Expr::DesignatedInitExprClass: + case Expr::ImplicitValueInitExprClass: + case Expr::ParenListExprClass: + case Expr::VAArgExprClass: + case Expr::AddrLabelExprClass: + case Expr::StmtExprClass: + case Expr::CXXMemberCallExprClass: + case Expr::CXXDynamicCastExprClass: + case Expr::CXXTypeidExprClass: + case Expr::CXXNullPtrLiteralExprClass: + 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::CXXBindTemporaryExprClass: + case Expr::CXXBindReferenceExprClass: + case Expr::CXXExprWithTemporariesClass: + case Expr::CXXTemporaryObjectExprClass: + case Expr::CXXUnresolvedConstructExprClass: + case Expr::CXXDependentScopeMemberExprClass: + case Expr::UnresolvedMemberExprClass: + case Expr::ObjCStringLiteralClass: + case Expr::ObjCEncodeExprClass: + case Expr::ObjCMessageExprClass: + case Expr::ObjCSelectorExprClass: + case Expr::ObjCProtocolExprClass: + case Expr::ObjCIvarRefExprClass: + case Expr::ObjCPropertyRefExprClass: + case Expr::ObjCImplicitSetterGetterRefExprClass: + case Expr::ObjCSuperExprClass: + case Expr::ObjCIsaExprClass: + case Expr::ShuffleVectorExprClass: + case Expr::BlockExprClass: + case Expr::BlockDeclRefExprClass: + case Expr::NoStmtClass: + return ICEDiag(2, E->getLocStart()); + + case Expr::GNUNullExprClass: + // GCC considers the GNU __null value to be an integral constant expression. + return NoDiag(); + + case Expr::ParenExprClass: + return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx); + case Expr::IntegerLiteralClass: + case Expr::CharacterLiteralClass: + case Expr::CXXBoolLiteralExprClass: + case Expr::CXXZeroInitValueExprClass: + case Expr::TypesCompatibleExprClass: + case Expr::UnaryTypeTraitExprClass: + return NoDiag(); + case Expr::CallExprClass: + case Expr::CXXOperatorCallExprClass: { + const CallExpr *CE = cast<CallExpr>(E); + if (CE->isBuiltinCall(Ctx)) + return CheckEvalInICE(E, Ctx); + return ICEDiag(2, E->getLocStart()); + } + case Expr::DeclRefExprClass: + if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl())) + return NoDiag(); + if (Ctx.getLangOptions().CPlusPlus && + E->getType().getCVRQualifiers() == Qualifiers::Const) { + const NamedDecl *D = cast<DeclRefExpr>(E)->getDecl(); + + // Parameter variables are never constants. Without this check, + // getAnyInitializer() can find a default argument, which leads + // to chaos. + if (isa<ParmVarDecl>(D)) + return ICEDiag(2, 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)) { + Qualifiers Quals = Ctx.getCanonicalType(Dcl->getType()).getQualifiers(); + if (Quals.hasVolatile() || !Quals.hasConst()) + return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation()); + + // Look for a declaration of this variable that has an initializer. + const VarDecl *ID = 0; + const Expr *Init = Dcl->getAnyInitializer(ID); + if (Init) { + if (ID->isInitKnownICE()) { + // We have already checked whether this subexpression is an + // integral constant expression. + if (ID->isInitICE()) + return NoDiag(); + else + return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation()); + } + + // It's an ICE whether or not the definition we found is + // out-of-line. See DR 721 and the discussion in Clang PR + // 6206 for details. + + if (Dcl->isCheckingICE()) { + return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation()); + } + + Dcl->setCheckingICE(); + ICEDiag Result = CheckICE(Init, Ctx); + // Cache the result of the ICE test. + Dcl->setInitKnownICE(Result.Val == 0); + return Result; + } + } + } + return ICEDiag(2, E->getLocStart()); + case Expr::UnaryOperatorClass: { + const UnaryOperator *Exp = cast<UnaryOperator>(E); + switch (Exp->getOpcode()) { + case UnaryOperator::PostInc: + case UnaryOperator::PostDec: + case UnaryOperator::PreInc: + case UnaryOperator::PreDec: + case UnaryOperator::AddrOf: + case UnaryOperator::Deref: + return ICEDiag(2, E->getLocStart()); + case UnaryOperator::Extension: + case UnaryOperator::LNot: + case UnaryOperator::Plus: + case UnaryOperator::Minus: + case UnaryOperator::Not: + case UnaryOperator::Real: + case UnaryOperator::Imag: + return CheckICE(Exp->getSubExpr(), Ctx); + case UnaryOperator::OffsetOf: + break; + } + + // OffsetOf falls through here. + } + case Expr::OffsetOfExprClass: { + // Note that per C99, offsetof must be an ICE. And AFAIK, using + // Evaluate matches the proposed gcc behavior for cases like + // "offsetof(struct s{int x[4];}, x[!.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::SizeOfAlignOfExprClass: { + const SizeOfAlignOfExpr *Exp = cast<SizeOfAlignOfExpr>(E); + if (Exp->isSizeOf() && Exp->getTypeOfArgument()->isVariableArrayType()) + return ICEDiag(2, E->getLocStart()); + return NoDiag(); + } + case Expr::BinaryOperatorClass: { + const BinaryOperator *Exp = cast<BinaryOperator>(E); + switch (Exp->getOpcode()) { + case BinaryOperator::PtrMemD: + case BinaryOperator::PtrMemI: + case BinaryOperator::Assign: + case BinaryOperator::MulAssign: + case BinaryOperator::DivAssign: + case BinaryOperator::RemAssign: + case BinaryOperator::AddAssign: + case BinaryOperator::SubAssign: + case BinaryOperator::ShlAssign: + case BinaryOperator::ShrAssign: + case BinaryOperator::AndAssign: + case BinaryOperator::XorAssign: + case BinaryOperator::OrAssign: + return ICEDiag(2, E->getLocStart()); + + case BinaryOperator::Mul: + case BinaryOperator::Div: + case BinaryOperator::Rem: + case BinaryOperator::Add: + case BinaryOperator::Sub: + case BinaryOperator::Shl: + case BinaryOperator::Shr: + case BinaryOperator::LT: + case BinaryOperator::GT: + case BinaryOperator::LE: + case BinaryOperator::GE: + case BinaryOperator::EQ: + case BinaryOperator::NE: + case BinaryOperator::And: + case BinaryOperator::Xor: + case BinaryOperator::Or: + case BinaryOperator::Comma: { + ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); + ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); + if (Exp->getOpcode() == BinaryOperator::Div || + Exp->getOpcode() == BinaryOperator::Rem) { + // Evaluate gives an error for undefined Div/Rem, so make sure + // we don't evaluate one. + if (LHSResult.Val != 2 && RHSResult.Val != 2) { + llvm::APSInt REval = Exp->getRHS()->EvaluateAsInt(Ctx); + if (REval == 0) + return ICEDiag(1, E->getLocStart()); + if (REval.isSigned() && REval.isAllOnesValue()) { + llvm::APSInt LEval = Exp->getLHS()->EvaluateAsInt(Ctx); + if (LEval.isMinSignedValue()) + return ICEDiag(1, E->getLocStart()); + } + } + } + if (Exp->getOpcode() == BinaryOperator::Comma) { + if (Ctx.getLangOptions().C99) { + // C99 6.6p3 introduces a strange edge case: comma can be in an ICE + // if it isn't evaluated. + if (LHSResult.Val == 0 && RHSResult.Val == 0) + return ICEDiag(1, E->getLocStart()); + } else { + // In both C89 and C++, commas in ICEs are illegal. + return ICEDiag(2, E->getLocStart()); + } + } + if (LHSResult.Val >= RHSResult.Val) + return LHSResult; + return RHSResult; + } + case BinaryOperator::LAnd: + case BinaryOperator::LOr: { + ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); + ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); + if (LHSResult.Val == 0 && RHSResult.Val == 1) { + // 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() == BinaryOperator::LAnd) != + (Exp->getLHS()->EvaluateAsInt(Ctx) == 0)) + return RHSResult; + return NoDiag(); + } + + if (LHSResult.Val >= RHSResult.Val) + return LHSResult; + return RHSResult; + } + } + } + case Expr::ImplicitCastExprClass: + case Expr::CStyleCastExprClass: + case Expr::CXXFunctionalCastExprClass: + case Expr::CXXStaticCastExprClass: + case Expr::CXXReinterpretCastExprClass: + case Expr::CXXConstCastExprClass: { + const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr(); + if (SubExpr->getType()->isIntegralType()) + return CheckICE(SubExpr, Ctx); + if (isa<FloatingLiteral>(SubExpr->IgnoreParens())) + return NoDiag(); + return ICEDiag(2, E->getLocStart()); + } + 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(Ctx) == Builtin::BI__builtin_constant_p) { + Expr::EvalResult EVResult; + if (!E->Evaluate(EVResult, Ctx) || EVResult.HasSideEffects || + !EVResult.Val.isInt()) { + return ICEDiag(2, E->getLocStart()); + } + return NoDiag(); + } + ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx); + ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx); + ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); + if (CondResult.Val == 2) + return CondResult; + if (TrueResult.Val == 2) + return TrueResult; + if (FalseResult.Val == 2) + return FalseResult; + if (CondResult.Val == 1) + return CondResult; + if (TrueResult.Val == 0 && FalseResult.Val == 0) + 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()->EvaluateAsInt(Ctx) == 0) { + return FalseResult; + } + return TrueResult; + } + case Expr::CXXDefaultArgExprClass: + return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx); + case Expr::ChooseExprClass: { + return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(Ctx), Ctx); + } + } + + // Silence a GCC warning + return ICEDiag(2, E->getLocStart()); +} + +bool Expr::isIntegerConstantExpr(llvm::APSInt &Result, ASTContext &Ctx, + SourceLocation *Loc, bool isEvaluated) const { + ICEDiag d = CheckICE(this, Ctx); + if (d.Val != 0) { + if (Loc) *Loc = d.Loc; + return false; + } + EvalResult EvalResult; + if (!Evaluate(EvalResult, Ctx)) + llvm_unreachable("ICE cannot be evaluated!"); + assert(!EvalResult.HasSideEffects && "ICE with side effects!"); + assert(EvalResult.Val.isInt() && "ICE that isn't integer!"); + Result = EvalResult.Val.getInt(); + return true; +} |
