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Diffstat (limited to 'lib/AST/ExprConstant.cpp')
| -rw-r--r-- | lib/AST/ExprConstant.cpp | 1723 |
1 files changed, 1723 insertions, 0 deletions
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp new file mode 100644 index 0000000..50fdcfd --- /dev/null +++ b/lib/AST/ExprConstant.cpp @@ -0,0 +1,1723 @@ +//===--- 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/RecordLayout.h" +#include "clang/AST/StmtVisitor.h" +#include "clang/AST/ASTDiagnostic.h" +#include "clang/Basic/TargetInfo.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/Support/Compiler.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) {} +}; + + +static bool EvaluateLValue(const Expr *E, APValue &Result, EvalInfo &Info); +static bool EvaluatePointer(const Expr *E, APValue &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, APValue &Result, EvalInfo &Info); + +//===----------------------------------------------------------------------===// +// Misc utilities +//===----------------------------------------------------------------------===// + +static bool HandleConversionToBool(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()) { + APValue PointerResult; + if (!EvaluatePointer(E, PointerResult, Info)) + return false; + // FIXME: Is this accurate for all kinds of bases? If not, what would + // the check look like? + Result = PointerResult.getLValueBase() || PointerResult.getLValueOffset(); + return true; + } else if (E->getType()->isAnyComplexType()) { + APValue 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; +} + +//===----------------------------------------------------------------------===// +// LValue Evaluation +//===----------------------------------------------------------------------===// +namespace { +class VISIBILITY_HIDDEN LValueExprEvaluator + : public StmtVisitor<LValueExprEvaluator, APValue> { + EvalInfo &Info; +public: + + LValueExprEvaluator(EvalInfo &info) : Info(info) {} + + APValue VisitStmt(Stmt *S) { + return APValue(); + } + + APValue VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + APValue VisitDeclRefExpr(DeclRefExpr *E); + APValue VisitBlockExpr(BlockExpr *E); + APValue VisitPredefinedExpr(PredefinedExpr *E) { return APValue(E, 0); } + APValue VisitCompoundLiteralExpr(CompoundLiteralExpr *E); + APValue VisitMemberExpr(MemberExpr *E); + APValue VisitStringLiteral(StringLiteral *E) { return APValue(E, 0); } + APValue VisitObjCEncodeExpr(ObjCEncodeExpr *E) { return APValue(E, 0); } + APValue VisitArraySubscriptExpr(ArraySubscriptExpr *E); + APValue VisitUnaryDeref(UnaryOperator *E); + APValue VisitUnaryExtension(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + APValue VisitChooseExpr(const ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + // FIXME: Missing: __real__, __imag__ +}; +} // end anonymous namespace + +static bool EvaluateLValue(const Expr* E, APValue& Result, EvalInfo &Info) { + Result = LValueExprEvaluator(Info).Visit(const_cast<Expr*>(E)); + return Result.isLValue(); +} + +APValue LValueExprEvaluator::VisitDeclRefExpr(DeclRefExpr *E) +{ + if (!E->hasGlobalStorage()) + return APValue(); + + if (isa<FunctionDecl>(E->getDecl())) { + return APValue(E, 0); + } else if (VarDecl* VD = dyn_cast<VarDecl>(E->getDecl())) { + if (!VD->getType()->isReferenceType()) + return APValue(E, 0); + if (VD->getInit()) + return Visit(VD->getInit()); + } + + return APValue(); +} + +APValue LValueExprEvaluator::VisitBlockExpr(BlockExpr *E) +{ + if (E->hasBlockDeclRefExprs()) + return APValue(); + + return APValue(E, 0); +} + +APValue LValueExprEvaluator::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { + if (E->isFileScope()) + return APValue(E, 0); + return APValue(); +} + +APValue LValueExprEvaluator::VisitMemberExpr(MemberExpr *E) { + APValue result; + QualType Ty; + if (E->isArrow()) { + if (!EvaluatePointer(E->getBase(), result, Info)) + return APValue(); + Ty = E->getBase()->getType()->getAsPointerType()->getPointeeType(); + } else { + result = Visit(E->getBase()); + if (result.isUninit()) + return APValue(); + Ty = E->getBase()->getType(); + } + + RecordDecl *RD = Ty->getAsRecordType()->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 APValue(); + + if (FD->getType()->isReferenceType()) + return APValue(); + + // FIXME: This is linear time. + unsigned i = 0; + for (RecordDecl::field_iterator Field = RD->field_begin(Info.Ctx), + FieldEnd = RD->field_end(Info.Ctx); + Field != FieldEnd; (void)++Field, ++i) { + if (*Field == FD) + break; + } + + result.setLValue(result.getLValueBase(), + result.getLValueOffset() + RL.getFieldOffset(i) / 8); + + return result; +} + +APValue LValueExprEvaluator::VisitArraySubscriptExpr(ArraySubscriptExpr *E) +{ + APValue Result; + + if (!EvaluatePointer(E->getBase(), Result, Info)) + return APValue(); + + APSInt Index; + if (!EvaluateInteger(E->getIdx(), Index, Info)) + return APValue(); + + uint64_t ElementSize = Info.Ctx.getTypeSize(E->getType()) / 8; + + uint64_t Offset = Index.getSExtValue() * ElementSize; + Result.setLValue(Result.getLValueBase(), + Result.getLValueOffset() + Offset); + return Result; +} + +APValue LValueExprEvaluator::VisitUnaryDeref(UnaryOperator *E) +{ + APValue Result; + if (!EvaluatePointer(E->getSubExpr(), Result, Info)) + return APValue(); + return Result; +} + +//===----------------------------------------------------------------------===// +// Pointer Evaluation +//===----------------------------------------------------------------------===// + +namespace { +class VISIBILITY_HIDDEN PointerExprEvaluator + : public StmtVisitor<PointerExprEvaluator, APValue> { + EvalInfo &Info; +public: + + PointerExprEvaluator(EvalInfo &info) : Info(info) {} + + APValue VisitStmt(Stmt *S) { + return APValue(); + } + + APValue VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + + APValue VisitBinaryOperator(const BinaryOperator *E); + APValue VisitCastExpr(const CastExpr* E); + APValue VisitUnaryExtension(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + APValue VisitUnaryAddrOf(const UnaryOperator *E); + APValue VisitObjCStringLiteral(ObjCStringLiteral *E) + { return APValue(E, 0); } + APValue VisitAddrLabelExpr(AddrLabelExpr *E) + { return APValue(E, 0); } + APValue VisitCallExpr(CallExpr *E); + APValue VisitBlockExpr(BlockExpr *E) { + if (!E->hasBlockDeclRefExprs()) + return APValue(E, 0); + return APValue(); + } + APValue VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) + { return APValue((Expr*)0, 0); } + APValue VisitConditionalOperator(ConditionalOperator *E); + APValue VisitChooseExpr(ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + APValue VisitCXXNullPtrLiteralExpr(CXXNullPtrLiteralExpr *E) + { return APValue((Expr*)0, 0); } + // FIXME: Missing: @protocol, @selector +}; +} // end anonymous namespace + +static bool EvaluatePointer(const Expr* E, APValue& Result, EvalInfo &Info) { + if (!E->getType()->hasPointerRepresentation()) + return false; + Result = PointerExprEvaluator(Info).Visit(const_cast<Expr*>(E)); + return Result.isLValue(); +} + +APValue PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { + if (E->getOpcode() != BinaryOperator::Add && + E->getOpcode() != BinaryOperator::Sub) + return APValue(); + + const Expr *PExp = E->getLHS(); + const Expr *IExp = E->getRHS(); + if (IExp->getType()->isPointerType()) + std::swap(PExp, IExp); + + APValue ResultLValue; + if (!EvaluatePointer(PExp, ResultLValue, Info)) + return APValue(); + + llvm::APSInt AdditionalOffset(32); + if (!EvaluateInteger(IExp, AdditionalOffset, Info)) + return APValue(); + + QualType PointeeType = PExp->getType()->getAsPointerType()->getPointeeType(); + uint64_t SizeOfPointee; + + // Explicitly handle GNU void* and function pointer arithmetic extensions. + if (PointeeType->isVoidType() || PointeeType->isFunctionType()) + SizeOfPointee = 1; + else + SizeOfPointee = Info.Ctx.getTypeSize(PointeeType) / 8; + + uint64_t Offset = ResultLValue.getLValueOffset(); + + if (E->getOpcode() == BinaryOperator::Add) + Offset += AdditionalOffset.getLimitedValue() * SizeOfPointee; + else + Offset -= AdditionalOffset.getLimitedValue() * SizeOfPointee; + + return APValue(ResultLValue.getLValueBase(), Offset); +} + +APValue PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { + APValue result; + if (EvaluateLValue(E->getSubExpr(), result, Info)) + return result; + return APValue(); +} + + +APValue PointerExprEvaluator::VisitCastExpr(const CastExpr* E) { + const Expr* SubExpr = E->getSubExpr(); + + // Check for pointer->pointer cast + if (SubExpr->getType()->isPointerType()) { + APValue Result; + if (EvaluatePointer(SubExpr, Result, Info)) + return Result; + return APValue(); + } + + if (SubExpr->getType()->isIntegralType()) { + APValue Result; + if (!EvaluateIntegerOrLValue(SubExpr, Result, Info)) + return APValue(); + + if (Result.isInt()) { + Result.getInt().extOrTrunc((unsigned)Info.Ctx.getTypeSize(E->getType())); + return APValue(0, Result.getInt().getZExtValue()); + } + + // Cast is of an lvalue, no need to change value. + return Result; + } + + if (SubExpr->getType()->isFunctionType() || + SubExpr->getType()->isBlockPointerType() || + SubExpr->getType()->isArrayType()) { + APValue Result; + if (EvaluateLValue(SubExpr, Result, Info)) + return Result; + return APValue(); + } + + return APValue(); +} + +APValue PointerExprEvaluator::VisitCallExpr(CallExpr *E) { + if (E->isBuiltinCall(Info.Ctx) == + Builtin::BI__builtin___CFStringMakeConstantString) + return APValue(E, 0); + return APValue(); +} + +APValue PointerExprEvaluator::VisitConditionalOperator(ConditionalOperator *E) { + bool BoolResult; + if (!HandleConversionToBool(E->getCond(), BoolResult, Info)) + return APValue(); + + Expr* EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr(); + + APValue Result; + if (EvaluatePointer(EvalExpr, Result, Info)) + return Result; + return APValue(); +} + +//===----------------------------------------------------------------------===// +// Vector Evaluation +//===----------------------------------------------------------------------===// + +namespace { + class VISIBILITY_HIDDEN 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 Expr* SE = E->getSubExpr(); + + // Check for vector->vector bitcast. + if (SE->getType()->isVectorType()) + return this->Visit(const_cast<Expr*>(SE)); + + return APValue(); +} + +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()->getAsVectorType(); + 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->getAsVectorType(); + 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 VISIBILITY_HIDDEN 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 VisitDeclRefExpr(const DeclRefExpr *E); + bool VisitCallExpr(const CallExpr *E); + bool VisitBinaryOperator(const BinaryOperator *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(), E); + } + + bool VisitChooseExpr(const ChooseExpr *E) { + return Visit(E->getChosenSubExpr(Info.Ctx)); + } + + bool VisitUnaryReal(const UnaryOperator *E); + bool VisitUnaryImag(const UnaryOperator *E); + +private: + unsigned GetAlignOfExpr(const Expr *E); + unsigned GetAlignOfType(QualType T); + // FIXME: Missing: array subscript of vector, member of vector +}; +} // end anonymous namespace + +static bool EvaluateIntegerOrLValue(const Expr* E, APValue &Result, EvalInfo &Info) { + if (!E->getType()->isIntegralType()) + return false; + + return IntExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E)); +} + +static bool EvaluateInteger(const Expr* E, APSInt &Result, EvalInfo &Info) { + APValue Val; + if (!EvaluateIntegerOrLValue(E, Val, Info) || !Val.isInt()) + return false; + Result = Val.getInt(); + return true; +} + +bool IntExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) { + // Enums are integer constant exprs. + if (const EnumConstantDecl *D = dyn_cast<EnumConstantDecl>(E->getDecl())) { + // FIXME: This is an ugly hack around the fact that enums don't set their + // signedness consistently; see PR3173. + APSInt SI = D->getInitVal(); + SI.setIsUnsigned(!E->getType()->isSignedIntegerType()); + // FIXME: This is an ugly hack around the fact that enums don't + // set their width (!?!) consistently; see PR3173. + SI.extOrTrunc(Info.Ctx.getIntWidth(E->getType())); + return Success(SI, 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 (E->getType().getCVRQualifiers() == QualType::Const) { + if (const VarDecl *D = dyn_cast<VarDecl>(E->getDecl())) { + if (APValue *V = D->getEvaluatedValue()) + return Success(V->getInt(), E); + if (const Expr *Init = D->getInit()) { + if (Visit(const_cast<Expr*>(Init))) { + // Cache the evaluated value in the variable declaration. + D->setEvaluatedValue(Info.Ctx, Result); + return true; + } + + 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->isStructureType()) + 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; +} + +bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) { + switch (E->isBuiltinCall(Info.Ctx)) { + default: + 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); + } +} + +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"); + APValue 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_i == APFloat::cmpGreaterThan || + CR_i == APFloat::cmpLessThan)), 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, E); + } + } + + if (LHSTy->isPointerType() && RHSTy->isPointerType()) { + if (E->getOpcode() == BinaryOperator::Sub || E->isEqualityOp()) { + APValue LHSValue; + if (!EvaluatePointer(E->getLHS(), LHSValue, Info)) + return false; + + APValue RHSValue; + if (!EvaluatePointer(E->getRHS(), RHSValue, Info)) + return false; + + // Reject any bases; this is conservative, but good enough for + // common uses + if (LHSValue.getLValueBase() || RHSValue.getLValueBase()) + return false; + + if (E->getOpcode() == BinaryOperator::Sub) { + const QualType Type = E->getLHS()->getType(); + const QualType ElementType = Type->getAsPointerType()->getPointeeType(); + + uint64_t D = LHSValue.getLValueOffset() - RHSValue.getLValueOffset(); + D /= Info.Ctx.getTypeSize(ElementType) / 8; + + return Success(D, 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()) { + uint64_t offset = Result.getLValueOffset(); + if (E->getOpcode() == BinaryOperator::Add) + offset += RHSVal.getInt().getZExtValue(); + else + offset -= RHSVal.getInt().getZExtValue(); + Result = APValue(Result.getLValueBase(), offset); + return true; + } + + // Handle cases like 4 + (unsigned long)&a + if (E->getOpcode() == BinaryOperator::Add && + RHSVal.isLValue() && Result.isInt()) { + uint64_t offset = RHSVal.getLValueOffset(); + offset += 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()); +} + +unsigned IntExprEvaluator::GetAlignOfType(QualType T) { + // Get information about the alignment. + unsigned CharSize = Info.Ctx.Target.getCharWidth(); + + // __alignof is defined to return the preferred alignment. + return Info.Ctx.getPreferredTypeAlign(T.getTypePtr()) / CharSize; +} + +unsigned 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.getDeclAlignInBytes(DRE->getDecl()); + + if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) + return Info.Ctx.getDeclAlignInBytes(ME->getMemberDecl()); + + return GetAlignOfType(E->getType()); +} + + +/// VisitSizeAlignOfExpr - Evaluate a sizeof or alignof with a result as the +/// expression's type. +bool IntExprEvaluator::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) { + QualType DstTy = E->getType(); + + // Handle alignof separately. + if (!E->isSizeOf()) { + if (E->isArgumentType()) + return Success(GetAlignOfType(E->getArgumentType()), E); + else + return Success(GetAlignOfExpr(E->getArgumentExpr()), E); + } + + QualType SrcTy = E->getTypeOfArgument(); + + // 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. + unsigned BitWidth = Info.Ctx.getTypeSize(SrcTy); + return Success(BitWidth / Info.Ctx.Target.getCharWidth(), 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. + APValue LV; + if (!EvaluateLValue(E->getSubExpr(), LV, Info)) + return false; + if (LV.getLValueBase()) + return false; + return Success(LV.getLValueOffset(), 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()) { + APValue 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; + + Result = LV; + return true; + } + + APSInt AsInt = Info.Ctx.MakeIntValue(LV.getLValueOffset(), 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. + APValue LV; + if (!EvaluateLValue(SubExpr, LV, Info)) + return false; + + if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(Info.Ctx.VoidPtrTy)) + return false; + + Result = LV; + return true; + } + + if (SrcType->isAnyComplexType()) { + APValue 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()) { + APValue 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()) { + APValue 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 VISIBILITY_HIDDEN 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 VisitChooseExpr(const ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + bool VisitUnaryExtension(const UnaryOperator *E) + { return Visit(E->getSubExpr()); } + + // FIXME: Missing: __real__/__imag__, array subscript of vector, + // member of vector, ImplicitValueInitExpr, + // conditional ?:, comma +}; +} // end anonymous namespace + +static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) { + return FloatExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E)); +} + +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_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 (const StringLiteral *S = + dyn_cast<StringLiteral>(E->getArg(0)->IgnoreParenCasts())) { + if (!S->isWide()) { + const llvm::fltSemantics &Sem = + Info.Ctx.getFloatTypeSemantics(E->getType()); + llvm::SmallString<16> s; + s.append(S->getStrData(), S->getStrData() + S->getByteLength()); + s += '\0'; + long l; + char *endp; + l = strtol(&s[0], &endp, 0); + if (endp != s.end()-1) + return false; + unsigned type = (unsigned int)l;; + Result = llvm::APFloat::getNaN(Sem, false, type); + return true; + } + } + return false; + + 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::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) { + // 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; +} + +//===----------------------------------------------------------------------===// +// Complex Evaluation (for float and integer) +//===----------------------------------------------------------------------===// + +namespace { +class VISIBILITY_HIDDEN ComplexExprEvaluator + : public StmtVisitor<ComplexExprEvaluator, APValue> { + EvalInfo &Info; + +public: + ComplexExprEvaluator(EvalInfo &info) : Info(info) {} + + //===--------------------------------------------------------------------===// + // Visitor Methods + //===--------------------------------------------------------------------===// + + APValue VisitStmt(Stmt *S) { + return APValue(); + } + + APValue VisitParenExpr(ParenExpr *E) { return Visit(E->getSubExpr()); } + + APValue VisitImaginaryLiteral(ImaginaryLiteral *E) { + Expr* SubExpr = E->getSubExpr(); + + if (SubExpr->getType()->isRealFloatingType()) { + APFloat Result(0.0); + + if (!EvaluateFloat(SubExpr, Result, Info)) + return APValue(); + + return APValue(APFloat(Result.getSemantics(), APFloat::fcZero, false), + Result); + } else { + assert(SubExpr->getType()->isIntegerType() && + "Unexpected imaginary literal."); + + llvm::APSInt Result; + if (!EvaluateInteger(SubExpr, Result, Info)) + return APValue(); + + llvm::APSInt Zero(Result.getBitWidth(), !Result.isSigned()); + Zero = 0; + return APValue(Zero, Result); + } + } + + APValue VisitCastExpr(CastExpr *E) { + Expr* SubExpr = E->getSubExpr(); + QualType EltType = E->getType()->getAsComplexType()->getElementType(); + QualType SubType = SubExpr->getType(); + + if (SubType->isRealFloatingType()) { + APFloat Result(0.0); + + if (!EvaluateFloat(SubExpr, Result, Info)) + return APValue(); + + if (EltType->isRealFloatingType()) { + Result = HandleFloatToFloatCast(EltType, SubType, Result, Info.Ctx); + return APValue(Result, + APFloat(Result.getSemantics(), APFloat::fcZero, false)); + } else { + llvm::APSInt IResult; + IResult = HandleFloatToIntCast(EltType, SubType, Result, Info.Ctx); + llvm::APSInt Zero(IResult.getBitWidth(), !IResult.isSigned()); + Zero = 0; + return APValue(IResult, Zero); + } + } else if (SubType->isIntegerType()) { + APSInt Result; + + if (!EvaluateInteger(SubExpr, Result, Info)) + return APValue(); + + if (EltType->isRealFloatingType()) { + APFloat FResult = + HandleIntToFloatCast(EltType, SubType, Result, Info.Ctx); + return APValue(FResult, + APFloat(FResult.getSemantics(), APFloat::fcZero, false)); + } else { + Result = HandleIntToIntCast(EltType, SubType, Result, Info.Ctx); + llvm::APSInt Zero(Result.getBitWidth(), !Result.isSigned()); + Zero = 0; + return APValue(Result, Zero); + } + } else if (const ComplexType *CT = SubType->getAsComplexType()) { + APValue Src; + + if (!EvaluateComplex(SubExpr, Src, Info)) + return APValue(); + + QualType SrcType = CT->getElementType(); + + if (Src.isComplexFloat()) { + if (EltType->isRealFloatingType()) { + return APValue(HandleFloatToFloatCast(EltType, SrcType, + Src.getComplexFloatReal(), + Info.Ctx), + HandleFloatToFloatCast(EltType, SrcType, + Src.getComplexFloatImag(), + Info.Ctx)); + } else { + return APValue(HandleFloatToIntCast(EltType, SrcType, + Src.getComplexFloatReal(), + Info.Ctx), + HandleFloatToIntCast(EltType, SrcType, + Src.getComplexFloatImag(), + Info.Ctx)); + } + } else { + assert(Src.isComplexInt() && "Invalid evaluate result."); + if (EltType->isRealFloatingType()) { + return APValue(HandleIntToFloatCast(EltType, SrcType, + Src.getComplexIntReal(), + Info.Ctx), + HandleIntToFloatCast(EltType, SrcType, + Src.getComplexIntImag(), + Info.Ctx)); + } else { + return APValue(HandleIntToIntCast(EltType, SrcType, + Src.getComplexIntReal(), + Info.Ctx), + HandleIntToIntCast(EltType, SrcType, + Src.getComplexIntImag(), + Info.Ctx)); + } + } + } + + // FIXME: Handle more casts. + return APValue(); + } + + APValue VisitBinaryOperator(const BinaryOperator *E); + APValue VisitChooseExpr(const ChooseExpr *E) + { return Visit(E->getChosenSubExpr(Info.Ctx)); } + APValue 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, APValue &Result, EvalInfo &Info) +{ + Result = ComplexExprEvaluator(Info).Visit(const_cast<Expr*>(E)); + assert((!Result.isComplexFloat() || + (&Result.getComplexFloatReal().getSemantics() == + &Result.getComplexFloatImag().getSemantics())) && + "Invalid complex evaluation."); + return Result.isComplexFloat() || Result.isComplexInt(); +} + +APValue ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) +{ + APValue Result, RHS; + + if (!EvaluateComplex(E->getLHS(), Result, Info)) + return APValue(); + + if (!EvaluateComplex(E->getRHS(), RHS, Info)) + return APValue(); + + assert(Result.isComplexFloat() == RHS.isComplexFloat() && + "Invalid operands to binary operator."); + switch (E->getOpcode()) { + default: return APValue(); + 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()) { + APValue 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 { + APValue LHS = Result; + Result.getComplexIntReal() = + (LHS.getComplexIntReal() * RHS.getComplexIntReal() - + LHS.getComplexIntImag() * RHS.getComplexIntImag()); + Result.getComplexIntImag() = + (LHS.getComplexIntReal() * RHS.getComplexIntImag() + + LHS.getComplexIntImag() * RHS.getComplexIntReal()); + } + break; + } + + return Result; +} + +//===----------------------------------------------------------------------===// +// 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 { + EvalInfo Info(Ctx, Result); + + if (getType()->isVectorType()) { + if (!EvaluateVector(this, Result.Val, Info)) + return false; + } else if (getType()->isIntegerType()) { + if (!IntExprEvaluator(Info, Result.Val).Visit(const_cast<Expr*>(this))) + return false; + } else if (getType()->hasPointerRepresentation()) { + if (!EvaluatePointer(this, Result.Val, Info)) + return false; + } else if (getType()->isRealFloatingType()) { + llvm::APFloat f(0.0); + if (!EvaluateFloat(this, f, Info)) + return false; + + Result.Val = APValue(f); + } else if (getType()->isAnyComplexType()) { + if (!EvaluateComplex(this, Result.Val, Info)) + return false; + } else + return false; + + return true; +} + +bool Expr::EvaluateAsLValue(EvalResult &Result, ASTContext &Ctx) const { + EvalInfo Info(Ctx, Result); + + return EvaluateLValue(this, Result.Val, Info) && !Result.HasSideEffects; +} + +/// 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; +} + +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(); +} |
