//===--- CGExprScalar.cpp - Emit LLVM Code for Scalar Exprs ---------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This contains code to emit Expr nodes with scalar LLVM types as LLVM code. // //===----------------------------------------------------------------------===// #include "CGCXXABI.h" #include "CGCleanup.h" #include "CGDebugInfo.h" #include "CGObjCRuntime.h" #include "CGOpenMPRuntime.h" #include "CodeGenFunction.h" #include "CodeGenModule.h" #include "ConstantEmitter.h" #include "TargetInfo.h" #include "clang/AST/ASTContext.h" #include "clang/AST/Attr.h" #include "clang/AST/DeclObjC.h" #include "clang/AST/Expr.h" #include "clang/AST/RecordLayout.h" #include "clang/AST/StmtVisitor.h" #include "clang/Basic/CodeGenOptions.h" #include "clang/Basic/TargetInfo.h" #include "llvm/ADT/APFixedPoint.h" #include "llvm/ADT/Optional.h" #include "llvm/IR/CFG.h" #include "llvm/IR/Constants.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/FixedPointBuilder.h" #include "llvm/IR/Function.h" #include "llvm/IR/GetElementPtrTypeIterator.h" #include "llvm/IR/GlobalVariable.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/IntrinsicsPowerPC.h" #include "llvm/IR/MatrixBuilder.h" #include "llvm/IR/Module.h" #include using namespace clang; using namespace CodeGen; using llvm::Value; //===----------------------------------------------------------------------===// // Scalar Expression Emitter //===----------------------------------------------------------------------===// namespace { /// Determine whether the given binary operation may overflow. /// Sets \p Result to the value of the operation for BO_Add, BO_Sub, BO_Mul, /// and signed BO_{Div,Rem}. For these opcodes, and for unsigned BO_{Div,Rem}, /// the returned overflow check is precise. The returned value is 'true' for /// all other opcodes, to be conservative. bool mayHaveIntegerOverflow(llvm::ConstantInt *LHS, llvm::ConstantInt *RHS, BinaryOperator::Opcode Opcode, bool Signed, llvm::APInt &Result) { // Assume overflow is possible, unless we can prove otherwise. bool Overflow = true; const auto &LHSAP = LHS->getValue(); const auto &RHSAP = RHS->getValue(); if (Opcode == BO_Add) { if (Signed) Result = LHSAP.sadd_ov(RHSAP, Overflow); else Result = LHSAP.uadd_ov(RHSAP, Overflow); } else if (Opcode == BO_Sub) { if (Signed) Result = LHSAP.ssub_ov(RHSAP, Overflow); else Result = LHSAP.usub_ov(RHSAP, Overflow); } else if (Opcode == BO_Mul) { if (Signed) Result = LHSAP.smul_ov(RHSAP, Overflow); else Result = LHSAP.umul_ov(RHSAP, Overflow); } else if (Opcode == BO_Div || Opcode == BO_Rem) { if (Signed && !RHS->isZero()) Result = LHSAP.sdiv_ov(RHSAP, Overflow); else return false; } return Overflow; } struct BinOpInfo { Value *LHS; Value *RHS; QualType Ty; // Computation Type. BinaryOperator::Opcode Opcode; // Opcode of BinOp to perform FPOptions FPFeatures; const Expr *E; // Entire expr, for error unsupported. May not be binop. /// Check if the binop can result in integer overflow. bool mayHaveIntegerOverflow() const { // Without constant input, we can't rule out overflow. auto *LHSCI = dyn_cast(LHS); auto *RHSCI = dyn_cast(RHS); if (!LHSCI || !RHSCI) return true; llvm::APInt Result; return ::mayHaveIntegerOverflow( LHSCI, RHSCI, Opcode, Ty->hasSignedIntegerRepresentation(), Result); } /// Check if the binop computes a division or a remainder. bool isDivremOp() const { return Opcode == BO_Div || Opcode == BO_Rem || Opcode == BO_DivAssign || Opcode == BO_RemAssign; } /// Check if the binop can result in an integer division by zero. bool mayHaveIntegerDivisionByZero() const { if (isDivremOp()) if (auto *CI = dyn_cast(RHS)) return CI->isZero(); return true; } /// Check if the binop can result in a float division by zero. bool mayHaveFloatDivisionByZero() const { if (isDivremOp()) if (auto *CFP = dyn_cast(RHS)) return CFP->isZero(); return true; } /// Check if at least one operand is a fixed point type. In such cases, this /// operation did not follow usual arithmetic conversion and both operands /// might not be of the same type. bool isFixedPointOp() const { // We cannot simply check the result type since comparison operations return // an int. if (const auto *BinOp = dyn_cast(E)) { QualType LHSType = BinOp->getLHS()->getType(); QualType RHSType = BinOp->getRHS()->getType(); return LHSType->isFixedPointType() || RHSType->isFixedPointType(); } if (const auto *UnOp = dyn_cast(E)) return UnOp->getSubExpr()->getType()->isFixedPointType(); return false; } }; static bool MustVisitNullValue(const Expr *E) { // If a null pointer expression's type is the C++0x nullptr_t, then // it's not necessarily a simple constant and it must be evaluated // for its potential side effects. return E->getType()->isNullPtrType(); } /// If \p E is a widened promoted integer, get its base (unpromoted) type. static llvm::Optional getUnwidenedIntegerType(const ASTContext &Ctx, const Expr *E) { const Expr *Base = E->IgnoreImpCasts(); if (E == Base) return llvm::None; QualType BaseTy = Base->getType(); if (!BaseTy->isPromotableIntegerType() || Ctx.getTypeSize(BaseTy) >= Ctx.getTypeSize(E->getType())) return llvm::None; return BaseTy; } /// Check if \p E is a widened promoted integer. static bool IsWidenedIntegerOp(const ASTContext &Ctx, const Expr *E) { return getUnwidenedIntegerType(Ctx, E).hasValue(); } /// Check if we can skip the overflow check for \p Op. static bool CanElideOverflowCheck(const ASTContext &Ctx, const BinOpInfo &Op) { assert((isa(Op.E) || isa(Op.E)) && "Expected a unary or binary operator"); // If the binop has constant inputs and we can prove there is no overflow, // we can elide the overflow check. if (!Op.mayHaveIntegerOverflow()) return true; // If a unary op has a widened operand, the op cannot overflow. if (const auto *UO = dyn_cast(Op.E)) return !UO->canOverflow(); // We usually don't need overflow checks for binops with widened operands. // Multiplication with promoted unsigned operands is a special case. const auto *BO = cast(Op.E); auto OptionalLHSTy = getUnwidenedIntegerType(Ctx, BO->getLHS()); if (!OptionalLHSTy) return false; auto OptionalRHSTy = getUnwidenedIntegerType(Ctx, BO->getRHS()); if (!OptionalRHSTy) return false; QualType LHSTy = *OptionalLHSTy; QualType RHSTy = *OptionalRHSTy; // This is the simple case: binops without unsigned multiplication, and with // widened operands. No overflow check is needed here. if ((Op.Opcode != BO_Mul && Op.Opcode != BO_MulAssign) || !LHSTy->isUnsignedIntegerType() || !RHSTy->isUnsignedIntegerType()) return true; // For unsigned multiplication the overflow check can be elided if either one // of the unpromoted types are less than half the size of the promoted type. unsigned PromotedSize = Ctx.getTypeSize(Op.E->getType()); return (2 * Ctx.getTypeSize(LHSTy)) < PromotedSize || (2 * Ctx.getTypeSize(RHSTy)) < PromotedSize; } class ScalarExprEmitter : public StmtVisitor { CodeGenFunction &CGF; CGBuilderTy &Builder; bool IgnoreResultAssign; llvm::LLVMContext &VMContext; public: ScalarExprEmitter(CodeGenFunction &cgf, bool ira=false) : CGF(cgf), Builder(CGF.Builder), IgnoreResultAssign(ira), VMContext(cgf.getLLVMContext()) { } //===--------------------------------------------------------------------===// // Utilities //===--------------------------------------------------------------------===// bool TestAndClearIgnoreResultAssign() { bool I = IgnoreResultAssign; IgnoreResultAssign = false; return I; } llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); } LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); } LValue EmitCheckedLValue(const Expr *E, CodeGenFunction::TypeCheckKind TCK) { return CGF.EmitCheckedLValue(E, TCK); } void EmitBinOpCheck(ArrayRef> Checks, const BinOpInfo &Info); Value *EmitLoadOfLValue(LValue LV, SourceLocation Loc) { return CGF.EmitLoadOfLValue(LV, Loc).getScalarVal(); } void EmitLValueAlignmentAssumption(const Expr *E, Value *V) { const AlignValueAttr *AVAttr = nullptr; if (const auto *DRE = dyn_cast(E)) { const ValueDecl *VD = DRE->getDecl(); if (VD->getType()->isReferenceType()) { if (const auto *TTy = dyn_cast(VD->getType().getNonReferenceType())) AVAttr = TTy->getDecl()->getAttr(); } else { // Assumptions for function parameters are emitted at the start of the // function, so there is no need to repeat that here, // unless the alignment-assumption sanitizer is enabled, // then we prefer the assumption over alignment attribute // on IR function param. if (isa(VD) && !CGF.SanOpts.has(SanitizerKind::Alignment)) return; AVAttr = VD->getAttr(); } } if (!AVAttr) if (const auto *TTy = dyn_cast(E->getType())) AVAttr = TTy->getDecl()->getAttr(); if (!AVAttr) return; Value *AlignmentValue = CGF.EmitScalarExpr(AVAttr->getAlignment()); llvm::ConstantInt *AlignmentCI = cast(AlignmentValue); CGF.emitAlignmentAssumption(V, E, AVAttr->getLocation(), AlignmentCI); } /// EmitLoadOfLValue - Given an expression with complex type that represents a /// value l-value, this method emits the address of the l-value, then loads /// and returns the result. Value *EmitLoadOfLValue(const Expr *E) { Value *V = EmitLoadOfLValue(EmitCheckedLValue(E, CodeGenFunction::TCK_Load), E->getExprLoc()); EmitLValueAlignmentAssumption(E, V); return V; } /// EmitConversionToBool - Convert the specified expression value to a /// boolean (i1) truth value. This is equivalent to "Val != 0". Value *EmitConversionToBool(Value *Src, QualType DstTy); /// Emit a check that a conversion from a floating-point type does not /// overflow. void EmitFloatConversionCheck(Value *OrigSrc, QualType OrigSrcType, Value *Src, QualType SrcType, QualType DstType, llvm::Type *DstTy, SourceLocation Loc); /// Known implicit conversion check kinds. /// Keep in sync with the enum of the same name in ubsan_handlers.h enum ImplicitConversionCheckKind : unsigned char { ICCK_IntegerTruncation = 0, // Legacy, was only used by clang 7. ICCK_UnsignedIntegerTruncation = 1, ICCK_SignedIntegerTruncation = 2, ICCK_IntegerSignChange = 3, ICCK_SignedIntegerTruncationOrSignChange = 4, }; /// Emit a check that an [implicit] truncation of an integer does not /// discard any bits. It is not UB, so we use the value after truncation. void EmitIntegerTruncationCheck(Value *Src, QualType SrcType, Value *Dst, QualType DstType, SourceLocation Loc); /// Emit a check that an [implicit] conversion of an integer does not change /// the sign of the value. It is not UB, so we use the value after conversion. /// NOTE: Src and Dst may be the exact same value! (point to the same thing) void EmitIntegerSignChangeCheck(Value *Src, QualType SrcType, Value *Dst, QualType DstType, SourceLocation Loc); /// Emit a conversion from the specified type to the specified destination /// type, both of which are LLVM scalar types. struct ScalarConversionOpts { bool TreatBooleanAsSigned; bool EmitImplicitIntegerTruncationChecks; bool EmitImplicitIntegerSignChangeChecks; ScalarConversionOpts() : TreatBooleanAsSigned(false), EmitImplicitIntegerTruncationChecks(false), EmitImplicitIntegerSignChangeChecks(false) {} ScalarConversionOpts(clang::SanitizerSet SanOpts) : TreatBooleanAsSigned(false), EmitImplicitIntegerTruncationChecks( SanOpts.hasOneOf(SanitizerKind::ImplicitIntegerTruncation)), EmitImplicitIntegerSignChangeChecks( SanOpts.has(SanitizerKind::ImplicitIntegerSignChange)) {} }; Value * EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy, SourceLocation Loc, ScalarConversionOpts Opts = ScalarConversionOpts()); /// Convert between either a fixed point and other fixed point or fixed point /// and an integer. Value *EmitFixedPointConversion(Value *Src, QualType SrcTy, QualType DstTy, SourceLocation Loc); /// Emit a conversion from the specified complex type to the specified /// destination type, where the destination type is an LLVM scalar type. Value *EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, QualType SrcTy, QualType DstTy, SourceLocation Loc); /// EmitNullValue - Emit a value that corresponds to null for the given type. Value *EmitNullValue(QualType Ty); /// EmitFloatToBoolConversion - Perform an FP to boolean conversion. Value *EmitFloatToBoolConversion(Value *V) { // Compare against 0.0 for fp scalars. llvm::Value *Zero = llvm::Constant::getNullValue(V->getType()); return Builder.CreateFCmpUNE(V, Zero, "tobool"); } /// EmitPointerToBoolConversion - Perform a pointer to boolean conversion. Value *EmitPointerToBoolConversion(Value *V, QualType QT) { Value *Zero = CGF.CGM.getNullPointer(cast(V->getType()), QT); return Builder.CreateICmpNE(V, Zero, "tobool"); } Value *EmitIntToBoolConversion(Value *V) { // Because of the type rules of C, we often end up computing a // logical value, then zero extending it to int, then wanting it // as a logical value again. Optimize this common case. if (llvm::ZExtInst *ZI = dyn_cast(V)) { if (ZI->getOperand(0)->getType() == Builder.getInt1Ty()) { Value *Result = ZI->getOperand(0); // If there aren't any more uses, zap the instruction to save space. // Note that there can be more uses, for example if this // is the result of an assignment. if (ZI->use_empty()) ZI->eraseFromParent(); return Result; } } return Builder.CreateIsNotNull(V, "tobool"); } //===--------------------------------------------------------------------===// // Visitor Methods //===--------------------------------------------------------------------===// Value *Visit(Expr *E) { ApplyDebugLocation DL(CGF, E); return StmtVisitor::Visit(E); } Value *VisitStmt(Stmt *S) { S->dump(llvm::errs(), CGF.getContext()); llvm_unreachable("Stmt can't have complex result type!"); } Value *VisitExpr(Expr *S); Value *VisitConstantExpr(ConstantExpr *E) { if (Value *Result = ConstantEmitter(CGF).tryEmitConstantExpr(E)) { if (E->isGLValue()) return CGF.Builder.CreateLoad(Address( Result, CGF.getContext().getTypeAlignInChars(E->getType()))); return Result; } return Visit(E->getSubExpr()); } Value *VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr()); } Value *VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) { return Visit(E->getReplacement()); } Value *VisitGenericSelectionExpr(GenericSelectionExpr *GE) { return Visit(GE->getResultExpr()); } Value *VisitCoawaitExpr(CoawaitExpr *S) { return CGF.EmitCoawaitExpr(*S).getScalarVal(); } Value *VisitCoyieldExpr(CoyieldExpr *S) { return CGF.EmitCoyieldExpr(*S).getScalarVal(); } Value *VisitUnaryCoawait(const UnaryOperator *E) { return Visit(E->getSubExpr()); } // Leaves. Value *VisitIntegerLiteral(const IntegerLiteral *E) { return Builder.getInt(E->getValue()); } Value *VisitFixedPointLiteral(const FixedPointLiteral *E) { return Builder.getInt(E->getValue()); } Value *VisitFloatingLiteral(const FloatingLiteral *E) { return llvm::ConstantFP::get(VMContext, E->getValue()); } Value *VisitCharacterLiteral(const CharacterLiteral *E) { return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); } Value *VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) { return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); } Value *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); } Value *VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) { return EmitNullValue(E->getType()); } Value *VisitGNUNullExpr(const GNUNullExpr *E) { return EmitNullValue(E->getType()); } Value *VisitOffsetOfExpr(OffsetOfExpr *E); Value *VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E); Value *VisitAddrLabelExpr(const AddrLabelExpr *E) { llvm::Value *V = CGF.GetAddrOfLabel(E->getLabel()); return Builder.CreateBitCast(V, ConvertType(E->getType())); } Value *VisitSizeOfPackExpr(SizeOfPackExpr *E) { return llvm::ConstantInt::get(ConvertType(E->getType()),E->getPackLength()); } Value *VisitPseudoObjectExpr(PseudoObjectExpr *E) { return CGF.EmitPseudoObjectRValue(E).getScalarVal(); } Value *VisitOpaqueValueExpr(OpaqueValueExpr *E) { if (E->isGLValue()) return EmitLoadOfLValue(CGF.getOrCreateOpaqueLValueMapping(E), E->getExprLoc()); // Otherwise, assume the mapping is the scalar directly. return CGF.getOrCreateOpaqueRValueMapping(E).getScalarVal(); } // l-values. Value *VisitDeclRefExpr(DeclRefExpr *E) { if (CodeGenFunction::ConstantEmission Constant = CGF.tryEmitAsConstant(E)) return CGF.emitScalarConstant(Constant, E); return EmitLoadOfLValue(E); } Value *VisitObjCSelectorExpr(ObjCSelectorExpr *E) { return CGF.EmitObjCSelectorExpr(E); } Value *VisitObjCProtocolExpr(ObjCProtocolExpr *E) { return CGF.EmitObjCProtocolExpr(E); } Value *VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) { return EmitLoadOfLValue(E); } Value *VisitObjCMessageExpr(ObjCMessageExpr *E) { if (E->getMethodDecl() && E->getMethodDecl()->getReturnType()->isReferenceType()) return EmitLoadOfLValue(E); return CGF.EmitObjCMessageExpr(E).getScalarVal(); } Value *VisitObjCIsaExpr(ObjCIsaExpr *E) { LValue LV = CGF.EmitObjCIsaExpr(E); Value *V = CGF.EmitLoadOfLValue(LV, E->getExprLoc()).getScalarVal(); return V; } Value *VisitObjCAvailabilityCheckExpr(ObjCAvailabilityCheckExpr *E) { VersionTuple Version = E->getVersion(); // If we're checking for a platform older than our minimum deployment // target, we can fold the check away. if (Version <= CGF.CGM.getTarget().getPlatformMinVersion()) return llvm::ConstantInt::get(Builder.getInt1Ty(), 1); return CGF.EmitBuiltinAvailable(Version); } Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E); Value *VisitMatrixSubscriptExpr(MatrixSubscriptExpr *E); Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E); Value *VisitConvertVectorExpr(ConvertVectorExpr *E); Value *VisitMemberExpr(MemberExpr *E); Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); } Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { // Strictly speaking, we shouldn't be calling EmitLoadOfLValue, which // transitively calls EmitCompoundLiteralLValue, here in C++ since compound // literals aren't l-values in C++. We do so simply because that's the // cleanest way to handle compound literals in C++. // See the discussion here: https://reviews.llvm.org/D64464 return EmitLoadOfLValue(E); } Value *VisitInitListExpr(InitListExpr *E); Value *VisitArrayInitIndexExpr(ArrayInitIndexExpr *E) { assert(CGF.getArrayInitIndex() && "ArrayInitIndexExpr not inside an ArrayInitLoopExpr?"); return CGF.getArrayInitIndex(); } Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { return EmitNullValue(E->getType()); } Value *VisitExplicitCastExpr(ExplicitCastExpr *E) { CGF.CGM.EmitExplicitCastExprType(E, &CGF); return VisitCastExpr(E); } Value *VisitCastExpr(CastExpr *E); Value *VisitCallExpr(const CallExpr *E) { if (E->getCallReturnType(CGF.getContext())->isReferenceType()) return EmitLoadOfLValue(E); Value *V = CGF.EmitCallExpr(E).getScalarVal(); EmitLValueAlignmentAssumption(E, V); return V; } Value *VisitStmtExpr(const StmtExpr *E); // Unary Operators. Value *VisitUnaryPostDec(const UnaryOperator *E) { LValue LV = EmitLValue(E->getSubExpr()); return EmitScalarPrePostIncDec(E, LV, false, false); } Value *VisitUnaryPostInc(const UnaryOperator *E) { LValue LV = EmitLValue(E->getSubExpr()); return EmitScalarPrePostIncDec(E, LV, true, false); } Value *VisitUnaryPreDec(const UnaryOperator *E) { LValue LV = EmitLValue(E->getSubExpr()); return EmitScalarPrePostIncDec(E, LV, false, true); } Value *VisitUnaryPreInc(const UnaryOperator *E) { LValue LV = EmitLValue(E->getSubExpr()); return EmitScalarPrePostIncDec(E, LV, true, true); } llvm::Value *EmitIncDecConsiderOverflowBehavior(const UnaryOperator *E, llvm::Value *InVal, bool IsInc); llvm::Value *EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV, bool isInc, bool isPre); Value *VisitUnaryAddrOf(const UnaryOperator *E) { if (isa(E->getType())) // never sugared return CGF.CGM.getMemberPointerConstant(E); return EmitLValue(E->getSubExpr()).getPointer(CGF); } Value *VisitUnaryDeref(const UnaryOperator *E) { if (E->getType()->isVoidType()) return Visit(E->getSubExpr()); // the actual value should be unused return EmitLoadOfLValue(E); } Value *VisitUnaryPlus(const UnaryOperator *E) { // This differs from gcc, though, most likely due to a bug in gcc. TestAndClearIgnoreResultAssign(); return Visit(E->getSubExpr()); } Value *VisitUnaryMinus (const UnaryOperator *E); Value *VisitUnaryNot (const UnaryOperator *E); Value *VisitUnaryLNot (const UnaryOperator *E); Value *VisitUnaryReal (const UnaryOperator *E); Value *VisitUnaryImag (const UnaryOperator *E); Value *VisitUnaryExtension(const UnaryOperator *E) { return Visit(E->getSubExpr()); } // C++ Value *VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E) { return EmitLoadOfLValue(E); } Value *VisitSourceLocExpr(SourceLocExpr *SLE) { auto &Ctx = CGF.getContext(); APValue Evaluated = SLE->EvaluateInContext(Ctx, CGF.CurSourceLocExprScope.getDefaultExpr()); return ConstantEmitter(CGF).emitAbstract(SLE->getLocation(), Evaluated, SLE->getType()); } Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { CodeGenFunction::CXXDefaultArgExprScope Scope(CGF, DAE); return Visit(DAE->getExpr()); } Value *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) { CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE); return Visit(DIE->getExpr()); } Value *VisitCXXThisExpr(CXXThisExpr *TE) { return CGF.LoadCXXThis(); } Value *VisitExprWithCleanups(ExprWithCleanups *E); Value *VisitCXXNewExpr(const CXXNewExpr *E) { return CGF.EmitCXXNewExpr(E); } Value *VisitCXXDeleteExpr(const CXXDeleteExpr *E) { CGF.EmitCXXDeleteExpr(E); return nullptr; } Value *VisitTypeTraitExpr(const TypeTraitExpr *E) { return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); } Value *VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E) { return Builder.getInt1(E->isSatisfied()); } Value *VisitRequiresExpr(const RequiresExpr *E) { return Builder.getInt1(E->isSatisfied()); } Value *VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) { return llvm::ConstantInt::get(Builder.getInt32Ty(), E->getValue()); } Value *VisitExpressionTraitExpr(const ExpressionTraitExpr *E) { return llvm::ConstantInt::get(Builder.getInt1Ty(), E->getValue()); } Value *VisitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr *E) { // C++ [expr.pseudo]p1: // The result shall only be used as the operand for the function call // operator (), and the result of such a call has type void. The only // effect is the evaluation of the postfix-expression before the dot or // arrow. CGF.EmitScalarExpr(E->getBase()); return nullptr; } Value *VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) { return EmitNullValue(E->getType()); } Value *VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); return nullptr; } Value *VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) { return Builder.getInt1(E->getValue()); } // Binary Operators. Value *EmitMul(const BinOpInfo &Ops) { if (Ops.Ty->isSignedIntegerOrEnumerationType()) { switch (CGF.getLangOpts().getSignedOverflowBehavior()) { case LangOptions::SOB_Defined: return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul"); case LangOptions::SOB_Undefined: if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) return Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul"); LLVM_FALLTHROUGH; case LangOptions::SOB_Trapping: if (CanElideOverflowCheck(CGF.getContext(), Ops)) return Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul"); return EmitOverflowCheckedBinOp(Ops); } } if (Ops.Ty->isConstantMatrixType()) { llvm::MatrixBuilder MB(Builder); // We need to check the types of the operands of the operator to get the // correct matrix dimensions. auto *BO = cast(Ops.E); auto *LHSMatTy = dyn_cast( BO->getLHS()->getType().getCanonicalType()); auto *RHSMatTy = dyn_cast( BO->getRHS()->getType().getCanonicalType()); if (LHSMatTy && RHSMatTy) return MB.CreateMatrixMultiply(Ops.LHS, Ops.RHS, LHSMatTy->getNumRows(), LHSMatTy->getNumColumns(), RHSMatTy->getNumColumns()); return MB.CreateScalarMultiply(Ops.LHS, Ops.RHS); } if (Ops.Ty->isUnsignedIntegerType() && CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) && !CanElideOverflowCheck(CGF.getContext(), Ops)) return EmitOverflowCheckedBinOp(Ops); if (Ops.LHS->getType()->isFPOrFPVectorTy()) { // Preserve the old values CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, Ops.FPFeatures); return Builder.CreateFMul(Ops.LHS, Ops.RHS, "mul"); } if (Ops.isFixedPointOp()) return EmitFixedPointBinOp(Ops); return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul"); } /// Create a binary op that checks for overflow. /// Currently only supports +, - and *. Value *EmitOverflowCheckedBinOp(const BinOpInfo &Ops); // Check for undefined division and modulus behaviors. void EmitUndefinedBehaviorIntegerDivAndRemCheck(const BinOpInfo &Ops, llvm::Value *Zero,bool isDiv); // Common helper for getting how wide LHS of shift is. static Value *GetWidthMinusOneValue(Value* LHS,Value* RHS); // Used for shifting constraints for OpenCL, do mask for powers of 2, URem for // non powers of two. Value *ConstrainShiftValue(Value *LHS, Value *RHS, const Twine &Name); Value *EmitDiv(const BinOpInfo &Ops); Value *EmitRem(const BinOpInfo &Ops); Value *EmitAdd(const BinOpInfo &Ops); Value *EmitSub(const BinOpInfo &Ops); Value *EmitShl(const BinOpInfo &Ops); Value *EmitShr(const BinOpInfo &Ops); Value *EmitAnd(const BinOpInfo &Ops) { return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and"); } Value *EmitXor(const BinOpInfo &Ops) { return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor"); } Value *EmitOr (const BinOpInfo &Ops) { return Builder.CreateOr(Ops.LHS, Ops.RHS, "or"); } // Helper functions for fixed point binary operations. Value *EmitFixedPointBinOp(const BinOpInfo &Ops); BinOpInfo EmitBinOps(const BinaryOperator *E); LValue EmitCompoundAssignLValue(const CompoundAssignOperator *E, Value *(ScalarExprEmitter::*F)(const BinOpInfo &), Value *&Result); Value *EmitCompoundAssign(const CompoundAssignOperator *E, Value *(ScalarExprEmitter::*F)(const BinOpInfo &)); // Binary operators and binary compound assignment operators. #define HANDLEBINOP(OP) \ Value *VisitBin ## OP(const BinaryOperator *E) { \ return Emit ## OP(EmitBinOps(E)); \ } \ Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) { \ return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP); \ } HANDLEBINOP(Mul) HANDLEBINOP(Div) HANDLEBINOP(Rem) HANDLEBINOP(Add) HANDLEBINOP(Sub) HANDLEBINOP(Shl) HANDLEBINOP(Shr) HANDLEBINOP(And) HANDLEBINOP(Xor) HANDLEBINOP(Or) #undef HANDLEBINOP // Comparisons. Value *EmitCompare(const BinaryOperator *E, llvm::CmpInst::Predicate UICmpOpc, llvm::CmpInst::Predicate SICmpOpc, llvm::CmpInst::Predicate FCmpOpc, bool IsSignaling); #define VISITCOMP(CODE, UI, SI, FP, SIG) \ Value *VisitBin##CODE(const BinaryOperator *E) { \ return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \ llvm::FCmpInst::FP, SIG); } VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT, true) VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT, true) VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE, true) VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE, true) VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ, false) VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE, false) #undef VISITCOMP Value *VisitBinAssign (const BinaryOperator *E); Value *VisitBinLAnd (const BinaryOperator *E); Value *VisitBinLOr (const BinaryOperator *E); Value *VisitBinComma (const BinaryOperator *E); Value *VisitBinPtrMemD(const Expr *E) { return EmitLoadOfLValue(E); } Value *VisitBinPtrMemI(const Expr *E) { return EmitLoadOfLValue(E); } Value *VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E) { return Visit(E->getSemanticForm()); } // Other Operators. Value *VisitBlockExpr(const BlockExpr *BE); Value *VisitAbstractConditionalOperator(const AbstractConditionalOperator *); Value *VisitChooseExpr(ChooseExpr *CE); Value *VisitVAArgExpr(VAArgExpr *VE); Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) { return CGF.EmitObjCStringLiteral(E); } Value *VisitObjCBoxedExpr(ObjCBoxedExpr *E) { return CGF.EmitObjCBoxedExpr(E); } Value *VisitObjCArrayLiteral(ObjCArrayLiteral *E) { return CGF.EmitObjCArrayLiteral(E); } Value *VisitObjCDictionaryLiteral(ObjCDictionaryLiteral *E) { return CGF.EmitObjCDictionaryLiteral(E); } Value *VisitAsTypeExpr(AsTypeExpr *CE); Value *VisitAtomicExpr(AtomicExpr *AE); }; } // end anonymous namespace. //===----------------------------------------------------------------------===// // Utilities //===----------------------------------------------------------------------===// /// EmitConversionToBool - Convert the specified expression value to a /// boolean (i1) truth value. This is equivalent to "Val != 0". Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) { assert(SrcType.isCanonical() && "EmitScalarConversion strips typedefs"); if (SrcType->isRealFloatingType()) return EmitFloatToBoolConversion(Src); if (const MemberPointerType *MPT = dyn_cast(SrcType)) return CGF.CGM.getCXXABI().EmitMemberPointerIsNotNull(CGF, Src, MPT); assert((SrcType->isIntegerType() || isa(Src->getType())) && "Unknown scalar type to convert"); if (isa(Src->getType())) return EmitIntToBoolConversion(Src); assert(isa(Src->getType())); return EmitPointerToBoolConversion(Src, SrcType); } void ScalarExprEmitter::EmitFloatConversionCheck( Value *OrigSrc, QualType OrigSrcType, Value *Src, QualType SrcType, QualType DstType, llvm::Type *DstTy, SourceLocation Loc) { assert(SrcType->isFloatingType() && "not a conversion from floating point"); if (!isa(DstTy)) return; CodeGenFunction::SanitizerScope SanScope(&CGF); using llvm::APFloat; using llvm::APSInt; llvm::Value *Check = nullptr; const llvm::fltSemantics &SrcSema = CGF.getContext().getFloatTypeSemantics(OrigSrcType); // Floating-point to integer. This has undefined behavior if the source is // +-Inf, NaN, or doesn't fit into the destination type (after truncation // to an integer). unsigned Width = CGF.getContext().getIntWidth(DstType); bool Unsigned = DstType->isUnsignedIntegerOrEnumerationType(); APSInt Min = APSInt::getMinValue(Width, Unsigned); APFloat MinSrc(SrcSema, APFloat::uninitialized); if (MinSrc.convertFromAPInt(Min, !Unsigned, APFloat::rmTowardZero) & APFloat::opOverflow) // Don't need an overflow check for lower bound. Just check for // -Inf/NaN. MinSrc = APFloat::getInf(SrcSema, true); else // Find the largest value which is too small to represent (before // truncation toward zero). MinSrc.subtract(APFloat(SrcSema, 1), APFloat::rmTowardNegative); APSInt Max = APSInt::getMaxValue(Width, Unsigned); APFloat MaxSrc(SrcSema, APFloat::uninitialized); if (MaxSrc.convertFromAPInt(Max, !Unsigned, APFloat::rmTowardZero) & APFloat::opOverflow) // Don't need an overflow check for upper bound. Just check for // +Inf/NaN. MaxSrc = APFloat::getInf(SrcSema, false); else // Find the smallest value which is too large to represent (before // truncation toward zero). MaxSrc.add(APFloat(SrcSema, 1), APFloat::rmTowardPositive); // If we're converting from __half, convert the range to float to match // the type of src. if (OrigSrcType->isHalfType()) { const llvm::fltSemantics &Sema = CGF.getContext().getFloatTypeSemantics(SrcType); bool IsInexact; MinSrc.convert(Sema, APFloat::rmTowardZero, &IsInexact); MaxSrc.convert(Sema, APFloat::rmTowardZero, &IsInexact); } llvm::Value *GE = Builder.CreateFCmpOGT(Src, llvm::ConstantFP::get(VMContext, MinSrc)); llvm::Value *LE = Builder.CreateFCmpOLT(Src, llvm::ConstantFP::get(VMContext, MaxSrc)); Check = Builder.CreateAnd(GE, LE); llvm::Constant *StaticArgs[] = {CGF.EmitCheckSourceLocation(Loc), CGF.EmitCheckTypeDescriptor(OrigSrcType), CGF.EmitCheckTypeDescriptor(DstType)}; CGF.EmitCheck(std::make_pair(Check, SanitizerKind::FloatCastOverflow), SanitizerHandler::FloatCastOverflow, StaticArgs, OrigSrc); } // Should be called within CodeGenFunction::SanitizerScope RAII scope. // Returns 'i1 false' when the truncation Src -> Dst was lossy. static std::pair> EmitIntegerTruncationCheckHelper(Value *Src, QualType SrcType, Value *Dst, QualType DstType, CGBuilderTy &Builder) { llvm::Type *SrcTy = Src->getType(); llvm::Type *DstTy = Dst->getType(); (void)DstTy; // Only used in assert() // This should be truncation of integral types. assert(Src != Dst); assert(SrcTy->getScalarSizeInBits() > Dst->getType()->getScalarSizeInBits()); assert(isa(SrcTy) && isa(DstTy) && "non-integer llvm type"); bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType(); bool DstSigned = DstType->isSignedIntegerOrEnumerationType(); // If both (src and dst) types are unsigned, then it's an unsigned truncation. // Else, it is a signed truncation. ScalarExprEmitter::ImplicitConversionCheckKind Kind; SanitizerMask Mask; if (!SrcSigned && !DstSigned) { Kind = ScalarExprEmitter::ICCK_UnsignedIntegerTruncation; Mask = SanitizerKind::ImplicitUnsignedIntegerTruncation; } else { Kind = ScalarExprEmitter::ICCK_SignedIntegerTruncation; Mask = SanitizerKind::ImplicitSignedIntegerTruncation; } llvm::Value *Check = nullptr; // 1. Extend the truncated value back to the same width as the Src. Check = Builder.CreateIntCast(Dst, SrcTy, DstSigned, "anyext"); // 2. Equality-compare with the original source value Check = Builder.CreateICmpEQ(Check, Src, "truncheck"); // If the comparison result is 'i1 false', then the truncation was lossy. return std::make_pair(Kind, std::make_pair(Check, Mask)); } static bool PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck( QualType SrcType, QualType DstType) { return SrcType->isIntegerType() && DstType->isIntegerType(); } void ScalarExprEmitter::EmitIntegerTruncationCheck(Value *Src, QualType SrcType, Value *Dst, QualType DstType, SourceLocation Loc) { if (!CGF.SanOpts.hasOneOf(SanitizerKind::ImplicitIntegerTruncation)) return; // We only care about int->int conversions here. // We ignore conversions to/from pointer and/or bool. if (!PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck(SrcType, DstType)) return; unsigned SrcBits = Src->getType()->getScalarSizeInBits(); unsigned DstBits = Dst->getType()->getScalarSizeInBits(); // This must be truncation. Else we do not care. if (SrcBits <= DstBits) return; assert(!DstType->isBooleanType() && "we should not get here with booleans."); // If the integer sign change sanitizer is enabled, // and we are truncating from larger unsigned type to smaller signed type, // let that next sanitizer deal with it. bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType(); bool DstSigned = DstType->isSignedIntegerOrEnumerationType(); if (CGF.SanOpts.has(SanitizerKind::ImplicitIntegerSignChange) && (!SrcSigned && DstSigned)) return; CodeGenFunction::SanitizerScope SanScope(&CGF); std::pair> Check = EmitIntegerTruncationCheckHelper(Src, SrcType, Dst, DstType, Builder); // If the comparison result is 'i1 false', then the truncation was lossy. // Do we care about this type of truncation? if (!CGF.SanOpts.has(Check.second.second)) return; llvm::Constant *StaticArgs[] = { CGF.EmitCheckSourceLocation(Loc), CGF.EmitCheckTypeDescriptor(SrcType), CGF.EmitCheckTypeDescriptor(DstType), llvm::ConstantInt::get(Builder.getInt8Ty(), Check.first)}; CGF.EmitCheck(Check.second, SanitizerHandler::ImplicitConversion, StaticArgs, {Src, Dst}); } // Should be called within CodeGenFunction::SanitizerScope RAII scope. // Returns 'i1 false' when the conversion Src -> Dst changed the sign. static std::pair> EmitIntegerSignChangeCheckHelper(Value *Src, QualType SrcType, Value *Dst, QualType DstType, CGBuilderTy &Builder) { llvm::Type *SrcTy = Src->getType(); llvm::Type *DstTy = Dst->getType(); assert(isa(SrcTy) && isa(DstTy) && "non-integer llvm type"); bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType(); bool DstSigned = DstType->isSignedIntegerOrEnumerationType(); (void)SrcSigned; // Only used in assert() (void)DstSigned; // Only used in assert() unsigned SrcBits = SrcTy->getScalarSizeInBits(); unsigned DstBits = DstTy->getScalarSizeInBits(); (void)SrcBits; // Only used in assert() (void)DstBits; // Only used in assert() assert(((SrcBits != DstBits) || (SrcSigned != DstSigned)) && "either the widths should be different, or the signednesses."); // NOTE: zero value is considered to be non-negative. auto EmitIsNegativeTest = [&Builder](Value *V, QualType VType, const char *Name) -> Value * { // Is this value a signed type? bool VSigned = VType->isSignedIntegerOrEnumerationType(); llvm::Type *VTy = V->getType(); if (!VSigned) { // If the value is unsigned, then it is never negative. // FIXME: can we encounter non-scalar VTy here? return llvm::ConstantInt::getFalse(VTy->getContext()); } // Get the zero of the same type with which we will be comparing. llvm::Constant *Zero = llvm::ConstantInt::get(VTy, 0); // %V.isnegative = icmp slt %V, 0 // I.e is %V *strictly* less than zero, does it have negative value? return Builder.CreateICmp(llvm::ICmpInst::ICMP_SLT, V, Zero, llvm::Twine(Name) + "." + V->getName() + ".negativitycheck"); }; // 1. Was the old Value negative? llvm::Value *SrcIsNegative = EmitIsNegativeTest(Src, SrcType, "src"); // 2. Is the new Value negative? llvm::Value *DstIsNegative = EmitIsNegativeTest(Dst, DstType, "dst"); // 3. Now, was the 'negativity status' preserved during the conversion? // NOTE: conversion from negative to zero is considered to change the sign. // (We want to get 'false' when the conversion changed the sign) // So we should just equality-compare the negativity statuses. llvm::Value *Check = nullptr; Check = Builder.CreateICmpEQ(SrcIsNegative, DstIsNegative, "signchangecheck"); // If the comparison result is 'false', then the conversion changed the sign. return std::make_pair( ScalarExprEmitter::ICCK_IntegerSignChange, std::make_pair(Check, SanitizerKind::ImplicitIntegerSignChange)); } void ScalarExprEmitter::EmitIntegerSignChangeCheck(Value *Src, QualType SrcType, Value *Dst, QualType DstType, SourceLocation Loc) { if (!CGF.SanOpts.has(SanitizerKind::ImplicitIntegerSignChange)) return; llvm::Type *SrcTy = Src->getType(); llvm::Type *DstTy = Dst->getType(); // We only care about int->int conversions here. // We ignore conversions to/from pointer and/or bool. if (!PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck(SrcType, DstType)) return; bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType(); bool DstSigned = DstType->isSignedIntegerOrEnumerationType(); unsigned SrcBits = SrcTy->getScalarSizeInBits(); unsigned DstBits = DstTy->getScalarSizeInBits(); // Now, we do not need to emit the check in *all* of the cases. // We can avoid emitting it in some obvious cases where it would have been // dropped by the opt passes (instcombine) always anyways. // If it's a cast between effectively the same type, no check. // NOTE: this is *not* equivalent to checking the canonical types. if (SrcSigned == DstSigned && SrcBits == DstBits) return; // At least one of the values needs to have signed type. // If both are unsigned, then obviously, neither of them can be negative. if (!SrcSigned && !DstSigned) return; // If the conversion is to *larger* *signed* type, then no check is needed. // Because either sign-extension happens (so the sign will remain), // or zero-extension will happen (the sign bit will be zero.) if ((DstBits > SrcBits) && DstSigned) return; if (CGF.SanOpts.has(SanitizerKind::ImplicitSignedIntegerTruncation) && (SrcBits > DstBits) && SrcSigned) { // If the signed integer truncation sanitizer is enabled, // and this is a truncation from signed type, then no check is needed. // Because here sign change check is interchangeable with truncation check. return; } // That's it. We can't rule out any more cases with the data we have. CodeGenFunction::SanitizerScope SanScope(&CGF); std::pair> Check; // Each of these checks needs to return 'false' when an issue was detected. ImplicitConversionCheckKind CheckKind; llvm::SmallVector, 2> Checks; // So we can 'and' all the checks together, and still get 'false', // if at least one of the checks detected an issue. Check = EmitIntegerSignChangeCheckHelper(Src, SrcType, Dst, DstType, Builder); CheckKind = Check.first; Checks.emplace_back(Check.second); if (CGF.SanOpts.has(SanitizerKind::ImplicitSignedIntegerTruncation) && (SrcBits > DstBits) && !SrcSigned && DstSigned) { // If the signed integer truncation sanitizer was enabled, // and we are truncating from larger unsigned type to smaller signed type, // let's handle the case we skipped in that check. Check = EmitIntegerTruncationCheckHelper(Src, SrcType, Dst, DstType, Builder); CheckKind = ICCK_SignedIntegerTruncationOrSignChange; Checks.emplace_back(Check.second); // If the comparison result is 'i1 false', then the truncation was lossy. } llvm::Constant *StaticArgs[] = { CGF.EmitCheckSourceLocation(Loc), CGF.EmitCheckTypeDescriptor(SrcType), CGF.EmitCheckTypeDescriptor(DstType), llvm::ConstantInt::get(Builder.getInt8Ty(), CheckKind)}; // EmitCheck() will 'and' all the checks together. CGF.EmitCheck(Checks, SanitizerHandler::ImplicitConversion, StaticArgs, {Src, Dst}); } /// Emit a conversion from the specified type to the specified destination type, /// both of which are LLVM scalar types. Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType, QualType DstType, SourceLocation Loc, ScalarConversionOpts Opts) { // All conversions involving fixed point types should be handled by the // EmitFixedPoint family functions. This is done to prevent bloating up this // function more, and although fixed point numbers are represented by // integers, we do not want to follow any logic that assumes they should be // treated as integers. // TODO(leonardchan): When necessary, add another if statement checking for // conversions to fixed point types from other types. if (SrcType->isFixedPointType()) { if (DstType->isBooleanType()) // It is important that we check this before checking if the dest type is // an integer because booleans are technically integer types. // We do not need to check the padding bit on unsigned types if unsigned // padding is enabled because overflow into this bit is undefined // behavior. return Builder.CreateIsNotNull(Src, "tobool"); if (DstType->isFixedPointType() || DstType->isIntegerType() || DstType->isRealFloatingType()) return EmitFixedPointConversion(Src, SrcType, DstType, Loc); llvm_unreachable( "Unhandled scalar conversion from a fixed point type to another type."); } else if (DstType->isFixedPointType()) { if (SrcType->isIntegerType() || SrcType->isRealFloatingType()) // This also includes converting booleans and enums to fixed point types. return EmitFixedPointConversion(Src, SrcType, DstType, Loc); llvm_unreachable( "Unhandled scalar conversion to a fixed point type from another type."); } QualType NoncanonicalSrcType = SrcType; QualType NoncanonicalDstType = DstType; SrcType = CGF.getContext().getCanonicalType(SrcType); DstType = CGF.getContext().getCanonicalType(DstType); if (SrcType == DstType) return Src; if (DstType->isVoidType()) return nullptr; llvm::Value *OrigSrc = Src; QualType OrigSrcType = SrcType; llvm::Type *SrcTy = Src->getType(); // Handle conversions to bool first, they are special: comparisons against 0. if (DstType->isBooleanType()) return EmitConversionToBool(Src, SrcType); llvm::Type *DstTy = ConvertType(DstType); // Cast from half through float if half isn't a native type. if (SrcType->isHalfType() && !CGF.getContext().getLangOpts().NativeHalfType) { // Cast to FP using the intrinsic if the half type itself isn't supported. if (DstTy->isFloatingPointTy()) { if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) return Builder.CreateCall( CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_from_fp16, DstTy), Src); } else { // Cast to other types through float, using either the intrinsic or FPExt, // depending on whether the half type itself is supported // (as opposed to operations on half, available with NativeHalfType). if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) { Src = Builder.CreateCall( CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_from_fp16, CGF.CGM.FloatTy), Src); } else { Src = Builder.CreateFPExt(Src, CGF.CGM.FloatTy, "conv"); } SrcType = CGF.getContext().FloatTy; SrcTy = CGF.FloatTy; } } // Ignore conversions like int -> uint. if (SrcTy == DstTy) { if (Opts.EmitImplicitIntegerSignChangeChecks) EmitIntegerSignChangeCheck(Src, NoncanonicalSrcType, Src, NoncanonicalDstType, Loc); return Src; } // Handle pointer conversions next: pointers can only be converted to/from // other pointers and integers. Check for pointer types in terms of LLVM, as // some native types (like Obj-C id) may map to a pointer type. if (auto DstPT = dyn_cast(DstTy)) { // The source value may be an integer, or a pointer. if (isa(SrcTy)) return Builder.CreateBitCast(Src, DstTy, "conv"); assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?"); // First, convert to the correct width so that we control the kind of // extension. llvm::Type *MiddleTy = CGF.CGM.getDataLayout().getIntPtrType(DstPT); bool InputSigned = SrcType->isSignedIntegerOrEnumerationType(); llvm::Value* IntResult = Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv"); // Then, cast to pointer. return Builder.CreateIntToPtr(IntResult, DstTy, "conv"); } if (isa(SrcTy)) { // Must be an ptr to int cast. assert(isa(DstTy) && "not ptr->int?"); return Builder.CreatePtrToInt(Src, DstTy, "conv"); } // A scalar can be splatted to an extended vector of the same element type if (DstType->isExtVectorType() && !SrcType->isVectorType()) { // Sema should add casts to make sure that the source expression's type is // the same as the vector's element type (sans qualifiers) assert(DstType->castAs()->getElementType().getTypePtr() == SrcType.getTypePtr() && "Splatted expr doesn't match with vector element type?"); // Splat the element across to all elements unsigned NumElements = cast(DstTy)->getNumElements(); return Builder.CreateVectorSplat(NumElements, Src, "splat"); } if (isa(SrcTy) || isa(DstTy)) { // Allow bitcast from vector to integer/fp of the same size. unsigned SrcSize = SrcTy->getPrimitiveSizeInBits(); unsigned DstSize = DstTy->getPrimitiveSizeInBits(); if (SrcSize == DstSize) return Builder.CreateBitCast(Src, DstTy, "conv"); // Conversions between vectors of different sizes are not allowed except // when vectors of half are involved. Operations on storage-only half // vectors require promoting half vector operands to float vectors and // truncating the result, which is either an int or float vector, to a // short or half vector. // Source and destination are both expected to be vectors. llvm::Type *SrcElementTy = cast(SrcTy)->getElementType(); llvm::Type *DstElementTy = cast(DstTy)->getElementType(); (void)DstElementTy; assert(((SrcElementTy->isIntegerTy() && DstElementTy->isIntegerTy()) || (SrcElementTy->isFloatingPointTy() && DstElementTy->isFloatingPointTy())) && "unexpected conversion between a floating-point vector and an " "integer vector"); // Truncate an i32 vector to an i16 vector. if (SrcElementTy->isIntegerTy()) return Builder.CreateIntCast(Src, DstTy, false, "conv"); // Truncate a float vector to a half vector. if (SrcSize > DstSize) return Builder.CreateFPTrunc(Src, DstTy, "conv"); // Promote a half vector to a float vector. return Builder.CreateFPExt(Src, DstTy, "conv"); } // Finally, we have the arithmetic types: real int/float. Value *Res = nullptr; llvm::Type *ResTy = DstTy; // An overflowing conversion has undefined behavior if either the source type // or the destination type is a floating-point type. However, we consider the // range of representable values for all floating-point types to be // [-inf,+inf], so no overflow can ever happen when the destination type is a // floating-point type. if (CGF.SanOpts.has(SanitizerKind::FloatCastOverflow) && OrigSrcType->isFloatingType()) EmitFloatConversionCheck(OrigSrc, OrigSrcType, Src, SrcType, DstType, DstTy, Loc); // Cast to half through float if half isn't a native type. if (DstType->isHalfType() && !CGF.getContext().getLangOpts().NativeHalfType) { // Make sure we cast in a single step if from another FP type. if (SrcTy->isFloatingPointTy()) { // Use the intrinsic if the half type itself isn't supported // (as opposed to operations on half, available with NativeHalfType). if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) return Builder.CreateCall( CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_to_fp16, SrcTy), Src); // If the half type is supported, just use an fptrunc. return Builder.CreateFPTrunc(Src, DstTy); } DstTy = CGF.FloatTy; } if (isa(SrcTy)) { bool InputSigned = SrcType->isSignedIntegerOrEnumerationType(); if (SrcType->isBooleanType() && Opts.TreatBooleanAsSigned) { InputSigned = true; } if (isa(DstTy)) Res = Builder.CreateIntCast(Src, DstTy, InputSigned, "conv"); else if (InputSigned) Res = Builder.CreateSIToFP(Src, DstTy, "conv"); else Res = Builder.CreateUIToFP(Src, DstTy, "conv"); } else if (isa(DstTy)) { assert(SrcTy->isFloatingPointTy() && "Unknown real conversion"); if (DstType->isSignedIntegerOrEnumerationType()) Res = Builder.CreateFPToSI(Src, DstTy, "conv"); else Res = Builder.CreateFPToUI(Src, DstTy, "conv"); } else { assert(SrcTy->isFloatingPointTy() && DstTy->isFloatingPointTy() && "Unknown real conversion"); if (DstTy->getTypeID() < SrcTy->getTypeID()) Res = Builder.CreateFPTrunc(Src, DstTy, "conv"); else Res = Builder.CreateFPExt(Src, DstTy, "conv"); } if (DstTy != ResTy) { if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) { assert(ResTy->isIntegerTy(16) && "Only half FP requires extra conversion"); Res = Builder.CreateCall( CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_to_fp16, CGF.CGM.FloatTy), Res); } else { Res = Builder.CreateFPTrunc(Res, ResTy, "conv"); } } if (Opts.EmitImplicitIntegerTruncationChecks) EmitIntegerTruncationCheck(Src, NoncanonicalSrcType, Res, NoncanonicalDstType, Loc); if (Opts.EmitImplicitIntegerSignChangeChecks) EmitIntegerSignChangeCheck(Src, NoncanonicalSrcType, Res, NoncanonicalDstType, Loc); return Res; } Value *ScalarExprEmitter::EmitFixedPointConversion(Value *Src, QualType SrcTy, QualType DstTy, SourceLocation Loc) { llvm::FixedPointBuilder FPBuilder(Builder); llvm::Value *Result; if (SrcTy->isRealFloatingType()) Result = FPBuilder.CreateFloatingToFixed(Src, CGF.getContext().getFixedPointSemantics(DstTy)); else if (DstTy->isRealFloatingType()) Result = FPBuilder.CreateFixedToFloating(Src, CGF.getContext().getFixedPointSemantics(SrcTy), ConvertType(DstTy)); else { auto SrcFPSema = CGF.getContext().getFixedPointSemantics(SrcTy); auto DstFPSema = CGF.getContext().getFixedPointSemantics(DstTy); if (DstTy->isIntegerType()) Result = FPBuilder.CreateFixedToInteger(Src, SrcFPSema, DstFPSema.getWidth(), DstFPSema.isSigned()); else if (SrcTy->isIntegerType()) Result = FPBuilder.CreateIntegerToFixed(Src, SrcFPSema.isSigned(), DstFPSema); else Result = FPBuilder.CreateFixedToFixed(Src, SrcFPSema, DstFPSema); } return Result; } /// Emit a conversion from the specified complex type to the specified /// destination type, where the destination type is an LLVM scalar type. Value *ScalarExprEmitter::EmitComplexToScalarConversion( CodeGenFunction::ComplexPairTy Src, QualType SrcTy, QualType DstTy, SourceLocation Loc) { // Get the source element type. SrcTy = SrcTy->castAs()->getElementType(); // Handle conversions to bool first, they are special: comparisons against 0. if (DstTy->isBooleanType()) { // Complex != 0 -> (Real != 0) | (Imag != 0) Src.first = EmitScalarConversion(Src.first, SrcTy, DstTy, Loc); Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy, Loc); return Builder.CreateOr(Src.first, Src.second, "tobool"); } // C99 6.3.1.7p2: "When a value of complex type is converted to a real type, // the imaginary part of the complex value is discarded and the value of the // real part is converted according to the conversion rules for the // corresponding real type. return EmitScalarConversion(Src.first, SrcTy, DstTy, Loc); } Value *ScalarExprEmitter::EmitNullValue(QualType Ty) { return CGF.EmitFromMemory(CGF.CGM.EmitNullConstant(Ty), Ty); } /// Emit a sanitization check for the given "binary" operation (which /// might actually be a unary increment which has been lowered to a binary /// operation). The check passes if all values in \p Checks (which are \c i1), /// are \c true. void ScalarExprEmitter::EmitBinOpCheck( ArrayRef> Checks, const BinOpInfo &Info) { assert(CGF.IsSanitizerScope); SanitizerHandler Check; SmallVector StaticData; SmallVector DynamicData; BinaryOperatorKind Opcode = Info.Opcode; if (BinaryOperator::isCompoundAssignmentOp(Opcode)) Opcode = BinaryOperator::getOpForCompoundAssignment(Opcode); StaticData.push_back(CGF.EmitCheckSourceLocation(Info.E->getExprLoc())); const UnaryOperator *UO = dyn_cast(Info.E); if (UO && UO->getOpcode() == UO_Minus) { Check = SanitizerHandler::NegateOverflow; StaticData.push_back(CGF.EmitCheckTypeDescriptor(UO->getType())); DynamicData.push_back(Info.RHS); } else { if (BinaryOperator::isShiftOp(Opcode)) { // Shift LHS negative or too large, or RHS out of bounds. Check = SanitizerHandler::ShiftOutOfBounds; const BinaryOperator *BO = cast(Info.E); StaticData.push_back( CGF.EmitCheckTypeDescriptor(BO->getLHS()->getType())); StaticData.push_back( CGF.EmitCheckTypeDescriptor(BO->getRHS()->getType())); } else if (Opcode == BO_Div || Opcode == BO_Rem) { // Divide or modulo by zero, or signed overflow (eg INT_MAX / -1). Check = SanitizerHandler::DivremOverflow; StaticData.push_back(CGF.EmitCheckTypeDescriptor(Info.Ty)); } else { // Arithmetic overflow (+, -, *). switch (Opcode) { case BO_Add: Check = SanitizerHandler::AddOverflow; break; case BO_Sub: Check = SanitizerHandler::SubOverflow; break; case BO_Mul: Check = SanitizerHandler::MulOverflow; break; default: llvm_unreachable("unexpected opcode for bin op check"); } StaticData.push_back(CGF.EmitCheckTypeDescriptor(Info.Ty)); } DynamicData.push_back(Info.LHS); DynamicData.push_back(Info.RHS); } CGF.EmitCheck(Checks, Check, StaticData, DynamicData); } //===----------------------------------------------------------------------===// // Visitor Methods //===----------------------------------------------------------------------===// Value *ScalarExprEmitter::VisitExpr(Expr *E) { CGF.ErrorUnsupported(E, "scalar expression"); if (E->getType()->isVoidType()) return nullptr; return llvm::UndefValue::get(CGF.ConvertType(E->getType())); } Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) { // Vector Mask Case if (E->getNumSubExprs() == 2) { Value *LHS = CGF.EmitScalarExpr(E->getExpr(0)); Value *RHS = CGF.EmitScalarExpr(E->getExpr(1)); Value *Mask; auto *LTy = cast(LHS->getType()); unsigned LHSElts = LTy->getNumElements(); Mask = RHS; auto *MTy = cast(Mask->getType()); // Mask off the high bits of each shuffle index. Value *MaskBits = llvm::ConstantInt::get(MTy, llvm::NextPowerOf2(LHSElts - 1) - 1); Mask = Builder.CreateAnd(Mask, MaskBits, "mask"); // newv = undef // mask = mask & maskbits // for each elt // n = extract mask i // x = extract val n // newv = insert newv, x, i auto *RTy = llvm::FixedVectorType::get(LTy->getElementType(), MTy->getNumElements()); Value* NewV = llvm::UndefValue::get(RTy); for (unsigned i = 0, e = MTy->getNumElements(); i != e; ++i) { Value *IIndx = llvm::ConstantInt::get(CGF.SizeTy, i); Value *Indx = Builder.CreateExtractElement(Mask, IIndx, "shuf_idx"); Value *VExt = Builder.CreateExtractElement(LHS, Indx, "shuf_elt"); NewV = Builder.CreateInsertElement(NewV, VExt, IIndx, "shuf_ins"); } return NewV; } Value* V1 = CGF.EmitScalarExpr(E->getExpr(0)); Value* V2 = CGF.EmitScalarExpr(E->getExpr(1)); SmallVector Indices; for (unsigned i = 2; i < E->getNumSubExprs(); ++i) { llvm::APSInt Idx = E->getShuffleMaskIdx(CGF.getContext(), i-2); // Check for -1 and output it as undef in the IR. if (Idx.isSigned() && Idx.isAllOnesValue()) Indices.push_back(-1); else Indices.push_back(Idx.getZExtValue()); } return Builder.CreateShuffleVector(V1, V2, Indices, "shuffle"); } Value *ScalarExprEmitter::VisitConvertVectorExpr(ConvertVectorExpr *E) { QualType SrcType = E->getSrcExpr()->getType(), DstType = E->getType(); Value *Src = CGF.EmitScalarExpr(E->getSrcExpr()); SrcType = CGF.getContext().getCanonicalType(SrcType); DstType = CGF.getContext().getCanonicalType(DstType); if (SrcType == DstType) return Src; assert(SrcType->isVectorType() && "ConvertVector source type must be a vector"); assert(DstType->isVectorType() && "ConvertVector destination type must be a vector"); llvm::Type *SrcTy = Src->getType(); llvm::Type *DstTy = ConvertType(DstType); // Ignore conversions like int -> uint. if (SrcTy == DstTy) return Src; QualType SrcEltType = SrcType->castAs()->getElementType(), DstEltType = DstType->castAs()->getElementType(); assert(SrcTy->isVectorTy() && "ConvertVector source IR type must be a vector"); assert(DstTy->isVectorTy() && "ConvertVector destination IR type must be a vector"); llvm::Type *SrcEltTy = cast(SrcTy)->getElementType(), *DstEltTy = cast(DstTy)->getElementType(); if (DstEltType->isBooleanType()) { assert((SrcEltTy->isFloatingPointTy() || isa(SrcEltTy)) && "Unknown boolean conversion"); llvm::Value *Zero = llvm::Constant::getNullValue(SrcTy); if (SrcEltTy->isFloatingPointTy()) { return Builder.CreateFCmpUNE(Src, Zero, "tobool"); } else { return Builder.CreateICmpNE(Src, Zero, "tobool"); } } // We have the arithmetic types: real int/float. Value *Res = nullptr; if (isa(SrcEltTy)) { bool InputSigned = SrcEltType->isSignedIntegerOrEnumerationType(); if (isa(DstEltTy)) Res = Builder.CreateIntCast(Src, DstTy, InputSigned, "conv"); else if (InputSigned) Res = Builder.CreateSIToFP(Src, DstTy, "conv"); else Res = Builder.CreateUIToFP(Src, DstTy, "conv"); } else if (isa(DstEltTy)) { assert(SrcEltTy->isFloatingPointTy() && "Unknown real conversion"); if (DstEltType->isSignedIntegerOrEnumerationType()) Res = Builder.CreateFPToSI(Src, DstTy, "conv"); else Res = Builder.CreateFPToUI(Src, DstTy, "conv"); } else { assert(SrcEltTy->isFloatingPointTy() && DstEltTy->isFloatingPointTy() && "Unknown real conversion"); if (DstEltTy->getTypeID() < SrcEltTy->getTypeID()) Res = Builder.CreateFPTrunc(Src, DstTy, "conv"); else Res = Builder.CreateFPExt(Src, DstTy, "conv"); } return Res; } Value *ScalarExprEmitter::VisitMemberExpr(MemberExpr *E) { if (CodeGenFunction::ConstantEmission Constant = CGF.tryEmitAsConstant(E)) { CGF.EmitIgnoredExpr(E->getBase()); return CGF.emitScalarConstant(Constant, E); } else { Expr::EvalResult Result; if (E->EvaluateAsInt(Result, CGF.getContext(), Expr::SE_AllowSideEffects)) { llvm::APSInt Value = Result.Val.getInt(); CGF.EmitIgnoredExpr(E->getBase()); return Builder.getInt(Value); } } return EmitLoadOfLValue(E); } Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { TestAndClearIgnoreResultAssign(); // Emit subscript expressions in rvalue context's. For most cases, this just // loads the lvalue formed by the subscript expr. However, we have to be // careful, because the base of a vector subscript is occasionally an rvalue, // so we can't get it as an lvalue. if (!E->getBase()->getType()->isVectorType()) return EmitLoadOfLValue(E); // Handle the vector case. The base must be a vector, the index must be an // integer value. Value *Base = Visit(E->getBase()); Value *Idx = Visit(E->getIdx()); QualType IdxTy = E->getIdx()->getType(); if (CGF.SanOpts.has(SanitizerKind::ArrayBounds)) CGF.EmitBoundsCheck(E, E->getBase(), Idx, IdxTy, /*Accessed*/true); return Builder.CreateExtractElement(Base, Idx, "vecext"); } Value *ScalarExprEmitter::VisitMatrixSubscriptExpr(MatrixSubscriptExpr *E) { TestAndClearIgnoreResultAssign(); // Handle the vector case. The base must be a vector, the index must be an // integer value. Value *RowIdx = Visit(E->getRowIdx()); Value *ColumnIdx = Visit(E->getColumnIdx()); Value *Matrix = Visit(E->getBase()); // TODO: Should we emit bounds checks with SanitizerKind::ArrayBounds? llvm::MatrixBuilder MB(Builder); return MB.CreateExtractElement( Matrix, RowIdx, ColumnIdx, E->getBase()->getType()->getAs()->getNumRows()); } static int getMaskElt(llvm::ShuffleVectorInst *SVI, unsigned Idx, unsigned Off) { int MV = SVI->getMaskValue(Idx); if (MV == -1) return -1; return Off + MV; } static int getAsInt32(llvm::ConstantInt *C, llvm::Type *I32Ty) { assert(llvm::ConstantInt::isValueValidForType(I32Ty, C->getZExtValue()) && "Index operand too large for shufflevector mask!"); return C->getZExtValue(); } Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) { bool Ignore = TestAndClearIgnoreResultAssign(); (void)Ignore; assert (Ignore == false && "init list ignored"); unsigned NumInitElements = E->getNumInits(); if (E->hadArrayRangeDesignator()) CGF.ErrorUnsupported(E, "GNU array range designator extension"); llvm::VectorType *VType = dyn_cast(ConvertType(E->getType())); if (!VType) { if (NumInitElements == 0) { // C++11 value-initialization for the scalar. return EmitNullValue(E->getType()); } // We have a scalar in braces. Just use the first element. return Visit(E->getInit(0)); } unsigned ResElts = cast(VType)->getNumElements(); // Loop over initializers collecting the Value for each, and remembering // whether the source was swizzle (ExtVectorElementExpr). This will allow // us to fold the shuffle for the swizzle into the shuffle for the vector // initializer, since LLVM optimizers generally do not want to touch // shuffles. unsigned CurIdx = 0; bool VIsUndefShuffle = false; llvm::Value *V = llvm::UndefValue::get(VType); for (unsigned i = 0; i != NumInitElements; ++i) { Expr *IE = E->getInit(i); Value *Init = Visit(IE); SmallVector Args; llvm::VectorType *VVT = dyn_cast(Init->getType()); // Handle scalar elements. If the scalar initializer is actually one // element of a different vector of the same width, use shuffle instead of // extract+insert. if (!VVT) { if (isa(IE)) { llvm::ExtractElementInst *EI = cast(Init); if (cast(EI->getVectorOperandType()) ->getNumElements() == ResElts) { llvm::ConstantInt *C = cast(EI->getIndexOperand()); Value *LHS = nullptr, *RHS = nullptr; if (CurIdx == 0) { // insert into undef -> shuffle (src, undef) // shufflemask must use an i32 Args.push_back(getAsInt32(C, CGF.Int32Ty)); Args.resize(ResElts, -1); LHS = EI->getVectorOperand(); RHS = V; VIsUndefShuffle = true; } else if (VIsUndefShuffle) { // insert into undefshuffle && size match -> shuffle (v, src) llvm::ShuffleVectorInst *SVV = cast(V); for (unsigned j = 0; j != CurIdx; ++j) Args.push_back(getMaskElt(SVV, j, 0)); Args.push_back(ResElts + C->getZExtValue()); Args.resize(ResElts, -1); LHS = cast(V)->getOperand(0); RHS = EI->getVectorOperand(); VIsUndefShuffle = false; } if (!Args.empty()) { V = Builder.CreateShuffleVector(LHS, RHS, Args); ++CurIdx; continue; } } } V = Builder.CreateInsertElement(V, Init, Builder.getInt32(CurIdx), "vecinit"); VIsUndefShuffle = false; ++CurIdx; continue; } unsigned InitElts = cast(VVT)->getNumElements(); // If the initializer is an ExtVecEltExpr (a swizzle), and the swizzle's // input is the same width as the vector being constructed, generate an // optimized shuffle of the swizzle input into the result. unsigned Offset = (CurIdx == 0) ? 0 : ResElts; if (isa(IE)) { llvm::ShuffleVectorInst *SVI = cast(Init); Value *SVOp = SVI->getOperand(0); auto *OpTy = cast(SVOp->getType()); if (OpTy->getNumElements() == ResElts) { for (unsigned j = 0; j != CurIdx; ++j) { // If the current vector initializer is a shuffle with undef, merge // this shuffle directly into it. if (VIsUndefShuffle) { Args.push_back(getMaskElt(cast(V), j, 0)); } else { Args.push_back(j); } } for (unsigned j = 0, je = InitElts; j != je; ++j) Args.push_back(getMaskElt(SVI, j, Offset)); Args.resize(ResElts, -1); if (VIsUndefShuffle) V = cast(V)->getOperand(0); Init = SVOp; } } // Extend init to result vector length, and then shuffle its contribution // to the vector initializer into V. if (Args.empty()) { for (unsigned j = 0; j != InitElts; ++j) Args.push_back(j); Args.resize(ResElts, -1); Init = Builder.CreateShuffleVector(Init, Args, "vext"); Args.clear(); for (unsigned j = 0; j != CurIdx; ++j) Args.push_back(j); for (unsigned j = 0; j != InitElts; ++j) Args.push_back(j + Offset); Args.resize(ResElts, -1); } // If V is undef, make sure it ends up on the RHS of the shuffle to aid // merging subsequent shuffles into this one. if (CurIdx == 0) std::swap(V, Init); V = Builder.CreateShuffleVector(V, Init, Args, "vecinit"); VIsUndefShuffle = isa(Init); CurIdx += InitElts; } // FIXME: evaluate codegen vs. shuffling against constant null vector. // Emit remaining default initializers. llvm::Type *EltTy = VType->getElementType(); // Emit remaining default initializers for (/* Do not initialize i*/; CurIdx < ResElts; ++CurIdx) { Value *Idx = Builder.getInt32(CurIdx); llvm::Value *Init = llvm::Constant::getNullValue(EltTy); V = Builder.CreateInsertElement(V, Init, Idx, "vecinit"); } return V; } bool CodeGenFunction::ShouldNullCheckClassCastValue(const CastExpr *CE) { const Expr *E = CE->getSubExpr(); if (CE->getCastKind() == CK_UncheckedDerivedToBase) return false; if (isa(E->IgnoreParens())) { // We always assume that 'this' is never null. return false; } if (const ImplicitCastExpr *ICE = dyn_cast(CE)) { // And that glvalue casts are never null. if (ICE->getValueKind() != VK_RValue) return false; } return true; } // VisitCastExpr - Emit code for an explicit or implicit cast. Implicit casts // have to handle a more broad range of conversions than explicit casts, as they // handle things like function to ptr-to-function decay etc. Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) { Expr *E = CE->getSubExpr(); QualType DestTy = CE->getType(); CastKind Kind = CE->getCastKind(); // These cases are generally not written to ignore the result of // evaluating their sub-expressions, so we clear this now. bool Ignored = TestAndClearIgnoreResultAssign(); // Since almost all cast kinds apply to scalars, this switch doesn't have // a default case, so the compiler will warn on a missing case. The cases // are in the same order as in the CastKind enum. switch (Kind) { case CK_Dependent: llvm_unreachable("dependent cast kind in IR gen!"); case CK_BuiltinFnToFnPtr: llvm_unreachable("builtin functions are handled elsewhere"); case CK_LValueBitCast: case CK_ObjCObjectLValueCast: { Address Addr = EmitLValue(E).getAddress(CGF); Addr = Builder.CreateElementBitCast(Addr, CGF.ConvertTypeForMem(DestTy)); LValue LV = CGF.MakeAddrLValue(Addr, DestTy); return EmitLoadOfLValue(LV, CE->getExprLoc()); } case CK_LValueToRValueBitCast: { LValue SourceLVal = CGF.EmitLValue(E); Address Addr = Builder.CreateElementBitCast(SourceLVal.getAddress(CGF), CGF.ConvertTypeForMem(DestTy)); LValue DestLV = CGF.MakeAddrLValue(Addr, DestTy); DestLV.setTBAAInfo(TBAAAccessInfo::getMayAliasInfo()); return EmitLoadOfLValue(DestLV, CE->getExprLoc()); } case CK_CPointerToObjCPointerCast: case CK_BlockPointerToObjCPointerCast: case CK_AnyPointerToBlockPointerCast: case CK_BitCast: { Value *Src = Visit(const_cast(E)); llvm::Type *SrcTy = Src->getType(); llvm::Type *DstTy = ConvertType(DestTy); if (SrcTy->isPtrOrPtrVectorTy() && DstTy->isPtrOrPtrVectorTy() && SrcTy->getPointerAddressSpace() != DstTy->getPointerAddressSpace()) { llvm_unreachable("wrong cast for pointers in different address spaces" "(must be an address space cast)!"); } if (CGF.SanOpts.has(SanitizerKind::CFIUnrelatedCast)) { if (auto PT = DestTy->getAs()) CGF.EmitVTablePtrCheckForCast(PT->getPointeeType(), Src, /*MayBeNull=*/true, CodeGenFunction::CFITCK_UnrelatedCast, CE->getBeginLoc()); } if (CGF.CGM.getCodeGenOpts().StrictVTablePointers) { const QualType SrcType = E->getType(); if (SrcType.mayBeNotDynamicClass() && DestTy.mayBeDynamicClass()) { // Casting to pointer that could carry dynamic information (provided by // invariant.group) requires launder. Src = Builder.CreateLaunderInvariantGroup(Src); } else if (SrcType.mayBeDynamicClass() && DestTy.mayBeNotDynamicClass()) { // Casting to pointer that does not carry dynamic information (provided // by invariant.group) requires stripping it. Note that we don't do it // if the source could not be dynamic type and destination could be // dynamic because dynamic information is already laundered. It is // because launder(strip(src)) == launder(src), so there is no need to // add extra strip before launder. Src = Builder.CreateStripInvariantGroup(Src); } } // Update heapallocsite metadata when there is an explicit pointer cast. if (auto *CI = dyn_cast(Src)) { if (CI->getMetadata("heapallocsite") && isa(CE)) { QualType PointeeType = DestTy->getPointeeType(); if (!PointeeType.isNull()) CGF.getDebugInfo()->addHeapAllocSiteMetadata(CI, PointeeType, CE->getExprLoc()); } } // If Src is a fixed vector and Dst is a scalable vector, and both have the // same element type, use the llvm.experimental.vector.insert intrinsic to // perform the bitcast. if (const auto *FixedSrc = dyn_cast(SrcTy)) { if (const auto *ScalableDst = dyn_cast(DstTy)) { if (FixedSrc->getElementType() == ScalableDst->getElementType()) { llvm::Value *UndefVec = llvm::UndefValue::get(DstTy); llvm::Value *Zero = llvm::Constant::getNullValue(CGF.CGM.Int64Ty); return Builder.CreateInsertVector(DstTy, UndefVec, Src, Zero, "castScalableSve"); } } } // If Src is a scalable vector and Dst is a fixed vector, and both have the // same element type, use the llvm.experimental.vector.extract intrinsic to // perform the bitcast. if (const auto *ScalableSrc = dyn_cast(SrcTy)) { if (const auto *FixedDst = dyn_cast(DstTy)) { if (ScalableSrc->getElementType() == FixedDst->getElementType()) { llvm::Value *Zero = llvm::Constant::getNullValue(CGF.CGM.Int64Ty); return Builder.CreateExtractVector(DstTy, Src, Zero, "castFixedSve"); } } } // Perform VLAT <-> VLST bitcast through memory. // TODO: since the llvm.experimental.vector.{insert,extract} intrinsics // require the element types of the vectors to be the same, we // need to keep this around for casting between predicates, or more // generally for bitcasts between VLAT <-> VLST where the element // types of the vectors are not the same, until we figure out a better // way of doing these casts. if ((isa(SrcTy) && isa(DstTy)) || (isa(SrcTy) && isa(DstTy))) { if (const CallExpr *CE = dyn_cast(E)) { // Call expressions can't have a scalar return unless the return type // is a reference type so an lvalue can't be emitted. Create a temp // alloca to store the call, bitcast the address then load. QualType RetTy = CE->getCallReturnType(CGF.getContext()); Address Addr = CGF.CreateDefaultAlignTempAlloca(SrcTy, "saved-call-rvalue"); LValue LV = CGF.MakeAddrLValue(Addr, RetTy); CGF.EmitStoreOfScalar(Src, LV); Addr = Builder.CreateElementBitCast(Addr, CGF.ConvertTypeForMem(DestTy), "castFixedSve"); LValue DestLV = CGF.MakeAddrLValue(Addr, DestTy); DestLV.setTBAAInfo(TBAAAccessInfo::getMayAliasInfo()); return EmitLoadOfLValue(DestLV, CE->getExprLoc()); } Address Addr = EmitLValue(E).getAddress(CGF); Addr = Builder.CreateElementBitCast(Addr, CGF.ConvertTypeForMem(DestTy)); LValue DestLV = CGF.MakeAddrLValue(Addr, DestTy); DestLV.setTBAAInfo(TBAAAccessInfo::getMayAliasInfo()); return EmitLoadOfLValue(DestLV, CE->getExprLoc()); } return Builder.CreateBitCast(Src, DstTy); } case CK_AddressSpaceConversion: { Expr::EvalResult Result; if (E->EvaluateAsRValue(Result, CGF.getContext()) && Result.Val.isNullPointer()) { // If E has side effect, it is emitted even if its final result is a // null pointer. In that case, a DCE pass should be able to // eliminate the useless instructions emitted during translating E. if (Result.HasSideEffects) Visit(E); return CGF.CGM.getNullPointer(cast( ConvertType(DestTy)), DestTy); } // Since target may map different address spaces in AST to the same address // space, an address space conversion may end up as a bitcast. return CGF.CGM.getTargetCodeGenInfo().performAddrSpaceCast( CGF, Visit(E), E->getType()->getPointeeType().getAddressSpace(), DestTy->getPointeeType().getAddressSpace(), ConvertType(DestTy)); } case CK_AtomicToNonAtomic: case CK_NonAtomicToAtomic: case CK_NoOp: case CK_UserDefinedConversion: return Visit(const_cast(E)); case CK_BaseToDerived: { const CXXRecordDecl *DerivedClassDecl = DestTy->getPointeeCXXRecordDecl(); assert(DerivedClassDecl && "BaseToDerived arg isn't a C++ object pointer!"); Address Base = CGF.EmitPointerWithAlignment(E); Address Derived = CGF.GetAddressOfDerivedClass(Base, DerivedClassDecl, CE->path_begin(), CE->path_end(), CGF.ShouldNullCheckClassCastValue(CE)); // C++11 [expr.static.cast]p11: Behavior is undefined if a downcast is // performed and the object is not of the derived type. if (CGF.sanitizePerformTypeCheck()) CGF.EmitTypeCheck(CodeGenFunction::TCK_DowncastPointer, CE->getExprLoc(), Derived.getPointer(), DestTy->getPointeeType()); if (CGF.SanOpts.has(SanitizerKind::CFIDerivedCast)) CGF.EmitVTablePtrCheckForCast( DestTy->getPointeeType(), Derived.getPointer(), /*MayBeNull=*/true, CodeGenFunction::CFITCK_DerivedCast, CE->getBeginLoc()); return Derived.getPointer(); } case CK_UncheckedDerivedToBase: case CK_DerivedToBase: { // The EmitPointerWithAlignment path does this fine; just discard // the alignment. return CGF.EmitPointerWithAlignment(CE).getPointer(); } case CK_Dynamic: { Address V = CGF.EmitPointerWithAlignment(E); const CXXDynamicCastExpr *DCE = cast(CE); return CGF.EmitDynamicCast(V, DCE); } case CK_ArrayToPointerDecay: return CGF.EmitArrayToPointerDecay(E).getPointer(); case CK_FunctionToPointerDecay: return EmitLValue(E).getPointer(CGF); case CK_NullToPointer: if (MustVisitNullValue(E)) CGF.EmitIgnoredExpr(E); return CGF.CGM.getNullPointer(cast(ConvertType(DestTy)), DestTy); case CK_NullToMemberPointer: { if (MustVisitNullValue(E)) CGF.EmitIgnoredExpr(E); const MemberPointerType *MPT = CE->getType()->getAs(); return CGF.CGM.getCXXABI().EmitNullMemberPointer(MPT); } case CK_ReinterpretMemberPointer: case CK_BaseToDerivedMemberPointer: case CK_DerivedToBaseMemberPointer: { Value *Src = Visit(E); // Note that the AST doesn't distinguish between checked and // unchecked member pointer conversions, so we always have to // implement checked conversions here. This is inefficient when // actual control flow may be required in order to perform the // check, which it is for data member pointers (but not member // function pointers on Itanium and ARM). return CGF.CGM.getCXXABI().EmitMemberPointerConversion(CGF, CE, Src); } case CK_ARCProduceObject: return CGF.EmitARCRetainScalarExpr(E); case CK_ARCConsumeObject: return CGF.EmitObjCConsumeObject(E->getType(), Visit(E)); case CK_ARCReclaimReturnedObject: return CGF.EmitARCReclaimReturnedObject(E, /*allowUnsafe*/ Ignored); case CK_ARCExtendBlockObject: return CGF.EmitARCExtendBlockObject(E); case CK_CopyAndAutoreleaseBlockObject: return CGF.EmitBlockCopyAndAutorelease(Visit(E), E->getType()); case CK_FloatingRealToComplex: case CK_FloatingComplexCast: case CK_IntegralRealToComplex: case CK_IntegralComplexCast: case CK_IntegralComplexToFloatingComplex: case CK_FloatingComplexToIntegralComplex: case CK_ConstructorConversion: case CK_ToUnion: llvm_unreachable("scalar cast to non-scalar value"); case CK_LValueToRValue: assert(CGF.getContext().hasSameUnqualifiedType(E->getType(), DestTy)); assert(E->isGLValue() && "lvalue-to-rvalue applied to r-value!"); return Visit(const_cast(E)); case CK_IntegralToPointer: { Value *Src = Visit(const_cast(E)); // First, convert to the correct width so that we control the kind of // extension. auto DestLLVMTy = ConvertType(DestTy); llvm::Type *MiddleTy = CGF.CGM.getDataLayout().getIntPtrType(DestLLVMTy); bool InputSigned = E->getType()->isSignedIntegerOrEnumerationType(); llvm::Value* IntResult = Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv"); auto *IntToPtr = Builder.CreateIntToPtr(IntResult, DestLLVMTy); if (CGF.CGM.getCodeGenOpts().StrictVTablePointers) { // Going from integer to pointer that could be dynamic requires reloading // dynamic information from invariant.group. if (DestTy.mayBeDynamicClass()) IntToPtr = Builder.CreateLaunderInvariantGroup(IntToPtr); } return IntToPtr; } case CK_PointerToIntegral: { assert(!DestTy->isBooleanType() && "bool should use PointerToBool"); auto *PtrExpr = Visit(E); if (CGF.CGM.getCodeGenOpts().StrictVTablePointers) { const QualType SrcType = E->getType(); // Casting to integer requires stripping dynamic information as it does // not carries it. if (SrcType.mayBeDynamicClass()) PtrExpr = Builder.CreateStripInvariantGroup(PtrExpr); } return Builder.CreatePtrToInt(PtrExpr, ConvertType(DestTy)); } case CK_ToVoid: { CGF.EmitIgnoredExpr(E); return nullptr; } case CK_VectorSplat: { llvm::Type *DstTy = ConvertType(DestTy); Value *Elt = Visit(const_cast(E)); // Splat the element across to all elements unsigned NumElements = cast(DstTy)->getNumElements(); return Builder.CreateVectorSplat(NumElements, Elt, "splat"); } case CK_FixedPointCast: return EmitScalarConversion(Visit(E), E->getType(), DestTy, CE->getExprLoc()); case CK_FixedPointToBoolean: assert(E->getType()->isFixedPointType() && "Expected src type to be fixed point type"); assert(DestTy->isBooleanType() && "Expected dest type to be boolean type"); return EmitScalarConversion(Visit(E), E->getType(), DestTy, CE->getExprLoc()); case CK_FixedPointToIntegral: assert(E->getType()->isFixedPointType() && "Expected src type to be fixed point type"); assert(DestTy->isIntegerType() && "Expected dest type to be an integer"); return EmitScalarConversion(Visit(E), E->getType(), DestTy, CE->getExprLoc()); case CK_IntegralToFixedPoint: assert(E->getType()->isIntegerType() && "Expected src type to be an integer"); assert(DestTy->isFixedPointType() && "Expected dest type to be fixed point type"); return EmitScalarConversion(Visit(E), E->getType(), DestTy, CE->getExprLoc()); case CK_IntegralCast: { ScalarConversionOpts Opts; if (auto *ICE = dyn_cast(CE)) { if (!ICE->isPartOfExplicitCast()) Opts = ScalarConversionOpts(CGF.SanOpts); } return EmitScalarConversion(Visit(E), E->getType(), DestTy, CE->getExprLoc(), Opts); } case CK_IntegralToFloating: case CK_FloatingToIntegral: case CK_FloatingCast: case CK_FixedPointToFloating: case CK_FloatingToFixedPoint: { CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, CE); return EmitScalarConversion(Visit(E), E->getType(), DestTy, CE->getExprLoc()); } case CK_BooleanToSignedIntegral: { ScalarConversionOpts Opts; Opts.TreatBooleanAsSigned = true; return EmitScalarConversion(Visit(E), E->getType(), DestTy, CE->getExprLoc(), Opts); } case CK_IntegralToBoolean: return EmitIntToBoolConversion(Visit(E)); case CK_PointerToBoolean: return EmitPointerToBoolConversion(Visit(E), E->getType()); case CK_FloatingToBoolean: { CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, CE); return EmitFloatToBoolConversion(Visit(E)); } case CK_MemberPointerToBoolean: { llvm::Value *MemPtr = Visit(E); const MemberPointerType *MPT = E->getType()->getAs(); return CGF.CGM.getCXXABI().EmitMemberPointerIsNotNull(CGF, MemPtr, MPT); } case CK_FloatingComplexToReal: case CK_IntegralComplexToReal: return CGF.EmitComplexExpr(E, false, true).first; case CK_FloatingComplexToBoolean: case CK_IntegralComplexToBoolean: { CodeGenFunction::ComplexPairTy V = CGF.EmitComplexExpr(E); // TODO: kill this function off, inline appropriate case here return EmitComplexToScalarConversion(V, E->getType(), DestTy, CE->getExprLoc()); } case CK_ZeroToOCLOpaqueType: { assert((DestTy->isEventT() || DestTy->isQueueT() || DestTy->isOCLIntelSubgroupAVCType()) && "CK_ZeroToOCLEvent cast on non-event type"); return llvm::Constant::getNullValue(ConvertType(DestTy)); } case CK_IntToOCLSampler: return CGF.CGM.createOpenCLIntToSamplerConversion(E, CGF); } // end of switch llvm_unreachable("unknown scalar cast"); } Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) { CodeGenFunction::StmtExprEvaluation eval(CGF); Address RetAlloca = CGF.EmitCompoundStmt(*E->getSubStmt(), !E->getType()->isVoidType()); if (!RetAlloca.isValid()) return nullptr; return CGF.EmitLoadOfScalar(CGF.MakeAddrLValue(RetAlloca, E->getType()), E->getExprLoc()); } Value *ScalarExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) { CodeGenFunction::RunCleanupsScope Scope(CGF); Value *V = Visit(E->getSubExpr()); // Defend against dominance problems caused by jumps out of expression // evaluation through the shared cleanup block. Scope.ForceCleanup({&V}); return V; } //===----------------------------------------------------------------------===// // Unary Operators //===----------------------------------------------------------------------===// static BinOpInfo createBinOpInfoFromIncDec(const UnaryOperator *E, llvm::Value *InVal, bool IsInc, FPOptions FPFeatures) { BinOpInfo BinOp; BinOp.LHS = InVal; BinOp.RHS = llvm::ConstantInt::get(InVal->getType(), 1, false); BinOp.Ty = E->getType(); BinOp.Opcode = IsInc ? BO_Add : BO_Sub; BinOp.FPFeatures = FPFeatures; BinOp.E = E; return BinOp; } llvm::Value *ScalarExprEmitter::EmitIncDecConsiderOverflowBehavior( const UnaryOperator *E, llvm::Value *InVal, bool IsInc) { llvm::Value *Amount = llvm::ConstantInt::get(InVal->getType(), IsInc ? 1 : -1, true); StringRef Name = IsInc ? "inc" : "dec"; switch (CGF.getLangOpts().getSignedOverflowBehavior()) { case LangOptions::SOB_Defined: return Builder.CreateAdd(InVal, Amount, Name); case LangOptions::SOB_Undefined: if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) return Builder.CreateNSWAdd(InVal, Amount, Name); LLVM_FALLTHROUGH; case LangOptions::SOB_Trapping: if (!E->canOverflow()) return Builder.CreateNSWAdd(InVal, Amount, Name); return EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec( E, InVal, IsInc, E->getFPFeaturesInEffect(CGF.getLangOpts()))); } llvm_unreachable("Unknown SignedOverflowBehaviorTy"); } namespace { /// Handles check and update for lastprivate conditional variables. class OMPLastprivateConditionalUpdateRAII { private: CodeGenFunction &CGF; const UnaryOperator *E; public: OMPLastprivateConditionalUpdateRAII(CodeGenFunction &CGF, const UnaryOperator *E) : CGF(CGF), E(E) {} ~OMPLastprivateConditionalUpdateRAII() { if (CGF.getLangOpts().OpenMP) CGF.CGM.getOpenMPRuntime().checkAndEmitLastprivateConditional( CGF, E->getSubExpr()); } }; } // namespace llvm::Value * ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV, bool isInc, bool isPre) { OMPLastprivateConditionalUpdateRAII OMPRegion(CGF, E); QualType type = E->getSubExpr()->getType(); llvm::PHINode *atomicPHI = nullptr; llvm::Value *value; llvm::Value *input; int amount = (isInc ? 1 : -1); bool isSubtraction = !isInc; if (const AtomicType *atomicTy = type->getAs()) { type = atomicTy->getValueType(); if (isInc && type->isBooleanType()) { llvm::Value *True = CGF.EmitToMemory(Builder.getTrue(), type); if (isPre) { Builder.CreateStore(True, LV.getAddress(CGF), LV.isVolatileQualified()) ->setAtomic(llvm::AtomicOrdering::SequentiallyConsistent); return Builder.getTrue(); } // For atomic bool increment, we just store true and return it for // preincrement, do an atomic swap with true for postincrement return Builder.CreateAtomicRMW( llvm::AtomicRMWInst::Xchg, LV.getPointer(CGF), True, llvm::AtomicOrdering::SequentiallyConsistent); } // Special case for atomic increment / decrement on integers, emit // atomicrmw instructions. We skip this if we want to be doing overflow // checking, and fall into the slow path with the atomic cmpxchg loop. if (!type->isBooleanType() && type->isIntegerType() && !(type->isUnsignedIntegerType() && CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) && CGF.getLangOpts().getSignedOverflowBehavior() != LangOptions::SOB_Trapping) { llvm::AtomicRMWInst::BinOp aop = isInc ? llvm::AtomicRMWInst::Add : llvm::AtomicRMWInst::Sub; llvm::Instruction::BinaryOps op = isInc ? llvm::Instruction::Add : llvm::Instruction::Sub; llvm::Value *amt = CGF.EmitToMemory( llvm::ConstantInt::get(ConvertType(type), 1, true), type); llvm::Value *old = Builder.CreateAtomicRMW(aop, LV.getPointer(CGF), amt, llvm::AtomicOrdering::SequentiallyConsistent); return isPre ? Builder.CreateBinOp(op, old, amt) : old; } value = EmitLoadOfLValue(LV, E->getExprLoc()); input = value; // For every other atomic operation, we need to emit a load-op-cmpxchg loop llvm::BasicBlock *startBB = Builder.GetInsertBlock(); llvm::BasicBlock *opBB = CGF.createBasicBlock("atomic_op", CGF.CurFn); value = CGF.EmitToMemory(value, type); Builder.CreateBr(opBB); Builder.SetInsertPoint(opBB); atomicPHI = Builder.CreatePHI(value->getType(), 2); atomicPHI->addIncoming(value, startBB); value = atomicPHI; } else { value = EmitLoadOfLValue(LV, E->getExprLoc()); input = value; } // Special case of integer increment that we have to check first: bool++. // Due to promotion rules, we get: // bool++ -> bool = bool + 1 // -> bool = (int)bool + 1 // -> bool = ((int)bool + 1 != 0) // An interesting aspect of this is that increment is always true. // Decrement does not have this property. if (isInc && type->isBooleanType()) { value = Builder.getTrue(); // Most common case by far: integer increment. } else if (type->isIntegerType()) { QualType promotedType; bool canPerformLossyDemotionCheck = false; if (type->isPromotableIntegerType()) { promotedType = CGF.getContext().getPromotedIntegerType(type); assert(promotedType != type && "Shouldn't promote to the same type."); canPerformLossyDemotionCheck = true; canPerformLossyDemotionCheck &= CGF.getContext().getCanonicalType(type) != CGF.getContext().getCanonicalType(promotedType); canPerformLossyDemotionCheck &= PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck( type, promotedType); assert((!canPerformLossyDemotionCheck || type->isSignedIntegerOrEnumerationType() || promotedType->isSignedIntegerOrEnumerationType() || ConvertType(type)->getScalarSizeInBits() == ConvertType(promotedType)->getScalarSizeInBits()) && "The following check expects that if we do promotion to different " "underlying canonical type, at least one of the types (either " "base or promoted) will be signed, or the bitwidths will match."); } if (CGF.SanOpts.hasOneOf( SanitizerKind::ImplicitIntegerArithmeticValueChange) && canPerformLossyDemotionCheck) { // While `x += 1` (for `x` with width less than int) is modeled as // promotion+arithmetics+demotion, and we can catch lossy demotion with // ease; inc/dec with width less than int can't overflow because of // promotion rules, so we omit promotion+demotion, which means that we can // not catch lossy "demotion". Because we still want to catch these cases // when the sanitizer is enabled, we perform the promotion, then perform // the increment/decrement in the wider type, and finally // perform the demotion. This will catch lossy demotions. value = EmitScalarConversion(value, type, promotedType, E->getExprLoc()); Value *amt = llvm::ConstantInt::get(value->getType(), amount, true); value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec"); // Do pass non-default ScalarConversionOpts so that sanitizer check is // emitted. value = EmitScalarConversion(value, promotedType, type, E->getExprLoc(), ScalarConversionOpts(CGF.SanOpts)); // Note that signed integer inc/dec with width less than int can't // overflow because of promotion rules; we're just eliding a few steps // here. } else if (E->canOverflow() && type->isSignedIntegerOrEnumerationType()) { value = EmitIncDecConsiderOverflowBehavior(E, value, isInc); } else if (E->canOverflow() && type->isUnsignedIntegerType() && CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) { value = EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec( E, value, isInc, E->getFPFeaturesInEffect(CGF.getLangOpts()))); } else { llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount, true); value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec"); } // Next most common: pointer increment. } else if (const PointerType *ptr = type->getAs()) { QualType type = ptr->getPointeeType(); // VLA types don't have constant size. if (const VariableArrayType *vla = CGF.getContext().getAsVariableArrayType(type)) { llvm::Value *numElts = CGF.getVLASize(vla).NumElts; if (!isInc) numElts = Builder.CreateNSWNeg(numElts, "vla.negsize"); if (CGF.getLangOpts().isSignedOverflowDefined()) value = Builder.CreateGEP(value, numElts, "vla.inc"); else value = CGF.EmitCheckedInBoundsGEP( value, numElts, /*SignedIndices=*/false, isSubtraction, E->getExprLoc(), "vla.inc"); // Arithmetic on function pointers (!) is just +-1. } else if (type->isFunctionType()) { llvm::Value *amt = Builder.getInt32(amount); value = CGF.EmitCastToVoidPtr(value); if (CGF.getLangOpts().isSignedOverflowDefined()) value = Builder.CreateGEP(value, amt, "incdec.funcptr"); else value = CGF.EmitCheckedInBoundsGEP(value, amt, /*SignedIndices=*/false, isSubtraction, E->getExprLoc(), "incdec.funcptr"); value = Builder.CreateBitCast(value, input->getType()); // For everything else, we can just do a simple increment. } else { llvm::Value *amt = Builder.getInt32(amount); if (CGF.getLangOpts().isSignedOverflowDefined()) value = Builder.CreateGEP(value, amt, "incdec.ptr"); else value = CGF.EmitCheckedInBoundsGEP(value, amt, /*SignedIndices=*/false, isSubtraction, E->getExprLoc(), "incdec.ptr"); } // Vector increment/decrement. } else if (type->isVectorType()) { if (type->hasIntegerRepresentation()) { llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount); value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec"); } else { value = Builder.CreateFAdd( value, llvm::ConstantFP::get(value->getType(), amount), isInc ? "inc" : "dec"); } // Floating point. } else if (type->isRealFloatingType()) { // Add the inc/dec to the real part. llvm::Value *amt; CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, E); if (type->isHalfType() && !CGF.getContext().getLangOpts().NativeHalfType) { // Another special case: half FP increment should be done via float if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) { value = Builder.CreateCall( CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_from_fp16, CGF.CGM.FloatTy), input, "incdec.conv"); } else { value = Builder.CreateFPExt(input, CGF.CGM.FloatTy, "incdec.conv"); } } if (value->getType()->isFloatTy()) amt = llvm::ConstantFP::get(VMContext, llvm::APFloat(static_cast(amount))); else if (value->getType()->isDoubleTy()) amt = llvm::ConstantFP::get(VMContext, llvm::APFloat(static_cast(amount))); else { // Remaining types are Half, LongDouble or __float128. Convert from float. llvm::APFloat F(static_cast(amount)); bool ignored; const llvm::fltSemantics *FS; // Don't use getFloatTypeSemantics because Half isn't // necessarily represented using the "half" LLVM type. if (value->getType()->isFP128Ty()) FS = &CGF.getTarget().getFloat128Format(); else if (value->getType()->isHalfTy()) FS = &CGF.getTarget().getHalfFormat(); else FS = &CGF.getTarget().getLongDoubleFormat(); F.convert(*FS, llvm::APFloat::rmTowardZero, &ignored); amt = llvm::ConstantFP::get(VMContext, F); } value = Builder.CreateFAdd(value, amt, isInc ? "inc" : "dec"); if (type->isHalfType() && !CGF.getContext().getLangOpts().NativeHalfType) { if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) { value = Builder.CreateCall( CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_to_fp16, CGF.CGM.FloatTy), value, "incdec.conv"); } else { value = Builder.CreateFPTrunc(value, input->getType(), "incdec.conv"); } } // Fixed-point types. } else if (type->isFixedPointType()) { // Fixed-point types are tricky. In some cases, it isn't possible to // represent a 1 or a -1 in the type at all. Piggyback off of // EmitFixedPointBinOp to avoid having to reimplement saturation. BinOpInfo Info; Info.E = E; Info.Ty = E->getType(); Info.Opcode = isInc ? BO_Add : BO_Sub; Info.LHS = value; Info.RHS = llvm::ConstantInt::get(value->getType(), 1, false); // If the type is signed, it's better to represent this as +(-1) or -(-1), // since -1 is guaranteed to be representable. if (type->isSignedFixedPointType()) { Info.Opcode = isInc ? BO_Sub : BO_Add; Info.RHS = Builder.CreateNeg(Info.RHS); } // Now, convert from our invented integer literal to the type of the unary // op. This will upscale and saturate if necessary. This value can become // undef in some cases. llvm::FixedPointBuilder FPBuilder(Builder); auto DstSema = CGF.getContext().getFixedPointSemantics(Info.Ty); Info.RHS = FPBuilder.CreateIntegerToFixed(Info.RHS, true, DstSema); value = EmitFixedPointBinOp(Info); // Objective-C pointer types. } else { const ObjCObjectPointerType *OPT = type->castAs(); value = CGF.EmitCastToVoidPtr(value); CharUnits size = CGF.getContext().getTypeSizeInChars(OPT->getObjectType()); if (!isInc) size = -size; llvm::Value *sizeValue = llvm::ConstantInt::get(CGF.SizeTy, size.getQuantity()); if (CGF.getLangOpts().isSignedOverflowDefined()) value = Builder.CreateGEP(value, sizeValue, "incdec.objptr"); else value = CGF.EmitCheckedInBoundsGEP(value, sizeValue, /*SignedIndices=*/false, isSubtraction, E->getExprLoc(), "incdec.objptr"); value = Builder.CreateBitCast(value, input->getType()); } if (atomicPHI) { llvm::BasicBlock *curBlock = Builder.GetInsertBlock(); llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn); auto Pair = CGF.EmitAtomicCompareExchange( LV, RValue::get(atomicPHI), RValue::get(value), E->getExprLoc()); llvm::Value *old = CGF.EmitToMemory(Pair.first.getScalarVal(), type); llvm::Value *success = Pair.second; atomicPHI->addIncoming(old, curBlock); Builder.CreateCondBr(success, contBB, atomicPHI->getParent()); Builder.SetInsertPoint(contBB); return isPre ? value : input; } // Store the updated result through the lvalue. if (LV.isBitField()) CGF.EmitStoreThroughBitfieldLValue(RValue::get(value), LV, &value); else CGF.EmitStoreThroughLValue(RValue::get(value), LV); // If this is a postinc, return the value read from memory, otherwise use the // updated value. return isPre ? value : input; } Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) { TestAndClearIgnoreResultAssign(); Value *Op = Visit(E->getSubExpr()); // Generate a unary FNeg for FP ops. if (Op->getType()->isFPOrFPVectorTy()) return Builder.CreateFNeg(Op, "fneg"); // Emit unary minus with EmitSub so we handle overflow cases etc. BinOpInfo BinOp; BinOp.RHS = Op; BinOp.LHS = llvm::Constant::getNullValue(BinOp.RHS->getType()); BinOp.Ty = E->getType(); BinOp.Opcode = BO_Sub; BinOp.FPFeatures = E->getFPFeaturesInEffect(CGF.getLangOpts()); BinOp.E = E; return EmitSub(BinOp); } Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) { TestAndClearIgnoreResultAssign(); Value *Op = Visit(E->getSubExpr()); return Builder.CreateNot(Op, "neg"); } Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) { // Perform vector logical not on comparison with zero vector. if (E->getType()->isVectorType() && E->getType()->castAs()->getVectorKind() == VectorType::GenericVector) { Value *Oper = Visit(E->getSubExpr()); Value *Zero = llvm::Constant::getNullValue(Oper->getType()); Value *Result; if (Oper->getType()->isFPOrFPVectorTy()) { CodeGenFunction::CGFPOptionsRAII FPOptsRAII( CGF, E->getFPFeaturesInEffect(CGF.getLangOpts())); Result = Builder.CreateFCmp(llvm::CmpInst::FCMP_OEQ, Oper, Zero, "cmp"); } else Result = Builder.CreateICmp(llvm::CmpInst::ICMP_EQ, Oper, Zero, "cmp"); return Builder.CreateSExt(Result, ConvertType(E->getType()), "sext"); } // Compare operand to zero. Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr()); // Invert value. // TODO: Could dynamically modify easy computations here. For example, if // the operand is an icmp ne, turn into icmp eq. BoolVal = Builder.CreateNot(BoolVal, "lnot"); // ZExt result to the expr type. return Builder.CreateZExt(BoolVal, ConvertType(E->getType()), "lnot.ext"); } Value *ScalarExprEmitter::VisitOffsetOfExpr(OffsetOfExpr *E) { // Try folding the offsetof to a constant. Expr::EvalResult EVResult; if (E->EvaluateAsInt(EVResult, CGF.getContext())) { llvm::APSInt Value = EVResult.Val.getInt(); return Builder.getInt(Value); } // Loop over the components of the offsetof to compute the value. unsigned n = E->getNumComponents(); llvm::Type* ResultType = ConvertType(E->getType()); llvm::Value* Result = llvm::Constant::getNullValue(ResultType); QualType CurrentType = E->getTypeSourceInfo()->getType(); for (unsigned i = 0; i != n; ++i) { OffsetOfNode ON = E->getComponent(i); llvm::Value *Offset = nullptr; switch (ON.getKind()) { case OffsetOfNode::Array: { // Compute the index Expr *IdxExpr = E->getIndexExpr(ON.getArrayExprIndex()); llvm::Value* Idx = CGF.EmitScalarExpr(IdxExpr); bool IdxSigned = IdxExpr->getType()->isSignedIntegerOrEnumerationType(); Idx = Builder.CreateIntCast(Idx, ResultType, IdxSigned, "conv"); // Save the element type CurrentType = CGF.getContext().getAsArrayType(CurrentType)->getElementType(); // Compute the element size llvm::Value* ElemSize = llvm::ConstantInt::get(ResultType, CGF.getContext().getTypeSizeInChars(CurrentType).getQuantity()); // Multiply out to compute the result Offset = Builder.CreateMul(Idx, ElemSize); break; } case OffsetOfNode::Field: { FieldDecl *MemberDecl = ON.getField(); RecordDecl *RD = CurrentType->castAs()->getDecl(); const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD); // Compute the index of the field in its parent. 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; ++Field, ++i) { if (*Field == MemberDecl) break; } assert(i < RL.getFieldCount() && "offsetof field in wrong type"); // Compute the offset to the field int64_t OffsetInt = RL.getFieldOffset(i) / CGF.getContext().getCharWidth(); Offset = llvm::ConstantInt::get(ResultType, OffsetInt); // Save the element type. CurrentType = MemberDecl->getType(); break; } case OffsetOfNode::Identifier: llvm_unreachable("dependent __builtin_offsetof"); case OffsetOfNode::Base: { if (ON.getBase()->isVirtual()) { CGF.ErrorUnsupported(E, "virtual base in offsetof"); continue; } RecordDecl *RD = CurrentType->castAs()->getDecl(); const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD); // Save the element type. CurrentType = ON.getBase()->getType(); // Compute the offset to the base. const RecordType *BaseRT = CurrentType->getAs(); CXXRecordDecl *BaseRD = cast(BaseRT->getDecl()); CharUnits OffsetInt = RL.getBaseClassOffset(BaseRD); Offset = llvm::ConstantInt::get(ResultType, OffsetInt.getQuantity()); break; } } Result = Builder.CreateAdd(Result, Offset); } return Result; } /// VisitUnaryExprOrTypeTraitExpr - Return the size or alignment of the type of /// argument of the sizeof expression as an integer. Value * ScalarExprEmitter::VisitUnaryExprOrTypeTraitExpr( const UnaryExprOrTypeTraitExpr *E) { QualType TypeToSize = E->getTypeOfArgument(); if (E->getKind() == UETT_SizeOf) { if (const VariableArrayType *VAT = CGF.getContext().getAsVariableArrayType(TypeToSize)) { if (E->isArgumentType()) { // sizeof(type) - make sure to emit the VLA size. CGF.EmitVariablyModifiedType(TypeToSize); } else { // C99 6.5.3.4p2: If the argument is an expression of type // VLA, it is evaluated. CGF.EmitIgnoredExpr(E->getArgumentExpr()); } auto VlaSize = CGF.getVLASize(VAT); llvm::Value *size = VlaSize.NumElts; // Scale the number of non-VLA elements by the non-VLA element size. CharUnits eltSize = CGF.getContext().getTypeSizeInChars(VlaSize.Type); if (!eltSize.isOne()) size = CGF.Builder.CreateNUWMul(CGF.CGM.getSize(eltSize), size); return size; } } else if (E->getKind() == UETT_OpenMPRequiredSimdAlign) { auto Alignment = CGF.getContext() .toCharUnitsFromBits(CGF.getContext().getOpenMPDefaultSimdAlign( E->getTypeOfArgument()->getPointeeType())) .getQuantity(); return llvm::ConstantInt::get(CGF.SizeTy, Alignment); } // If this isn't sizeof(vla), the result must be constant; use the constant // folding logic so we don't have to duplicate it here. return Builder.getInt(E->EvaluateKnownConstInt(CGF.getContext())); } Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) { Expr *Op = E->getSubExpr(); if (Op->getType()->isAnyComplexType()) { // If it's an l-value, load through the appropriate subobject l-value. // Note that we have to ask E because Op might be an l-value that // this won't work for, e.g. an Obj-C property. if (E->isGLValue()) return CGF.EmitLoadOfLValue(CGF.EmitLValue(E), E->getExprLoc()).getScalarVal(); // Otherwise, calculate and project. return CGF.EmitComplexExpr(Op, false, true).first; } return Visit(Op); } Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) { Expr *Op = E->getSubExpr(); if (Op->getType()->isAnyComplexType()) { // If it's an l-value, load through the appropriate subobject l-value. // Note that we have to ask E because Op might be an l-value that // this won't work for, e.g. an Obj-C property. if (Op->isGLValue()) return CGF.EmitLoadOfLValue(CGF.EmitLValue(E), E->getExprLoc()).getScalarVal(); // Otherwise, calculate and project. return CGF.EmitComplexExpr(Op, true, false).second; } // __imag on a scalar returns zero. Emit the subexpr to ensure side // effects are evaluated, but not the actual value. if (Op->isGLValue()) CGF.EmitLValue(Op); else CGF.EmitScalarExpr(Op, true); return llvm::Constant::getNullValue(ConvertType(E->getType())); } //===----------------------------------------------------------------------===// // Binary Operators //===----------------------------------------------------------------------===// BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) { TestAndClearIgnoreResultAssign(); BinOpInfo Result; Result.LHS = Visit(E->getLHS()); Result.RHS = Visit(E->getRHS()); Result.Ty = E->getType(); Result.Opcode = E->getOpcode(); Result.FPFeatures = E->getFPFeaturesInEffect(CGF.getLangOpts()); Result.E = E; return Result; } LValue ScalarExprEmitter::EmitCompoundAssignLValue( const CompoundAssignOperator *E, Value *(ScalarExprEmitter::*Func)(const BinOpInfo &), Value *&Result) { QualType LHSTy = E->getLHS()->getType(); BinOpInfo OpInfo; if (E->getComputationResultType()->isAnyComplexType()) return CGF.EmitScalarCompoundAssignWithComplex(E, Result); // Emit the RHS first. __block variables need to have the rhs evaluated // first, plus this should improve codegen a little. OpInfo.RHS = Visit(E->getRHS()); OpInfo.Ty = E->getComputationResultType(); OpInfo.Opcode = E->getOpcode(); OpInfo.FPFeatures = E->getFPFeaturesInEffect(CGF.getLangOpts()); OpInfo.E = E; // Load/convert the LHS. LValue LHSLV = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store); llvm::PHINode *atomicPHI = nullptr; if (const AtomicType *atomicTy = LHSTy->getAs()) { QualType type = atomicTy->getValueType(); if (!type->isBooleanType() && type->isIntegerType() && !(type->isUnsignedIntegerType() && CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) && CGF.getLangOpts().getSignedOverflowBehavior() != LangOptions::SOB_Trapping) { llvm::AtomicRMWInst::BinOp AtomicOp = llvm::AtomicRMWInst::BAD_BINOP; llvm::Instruction::BinaryOps Op; switch (OpInfo.Opcode) { // We don't have atomicrmw operands for *, %, /, <<, >> case BO_MulAssign: case BO_DivAssign: case BO_RemAssign: case BO_ShlAssign: case BO_ShrAssign: break; case BO_AddAssign: AtomicOp = llvm::AtomicRMWInst::Add; Op = llvm::Instruction::Add; break; case BO_SubAssign: AtomicOp = llvm::AtomicRMWInst::Sub; Op = llvm::Instruction::Sub; break; case BO_AndAssign: AtomicOp = llvm::AtomicRMWInst::And; Op = llvm::Instruction::And; break; case BO_XorAssign: AtomicOp = llvm::AtomicRMWInst::Xor; Op = llvm::Instruction::Xor; break; case BO_OrAssign: AtomicOp = llvm::AtomicRMWInst::Or; Op = llvm::Instruction::Or; break; default: llvm_unreachable("Invalid compound assignment type"); } if (AtomicOp != llvm::AtomicRMWInst::BAD_BINOP) { llvm::Value *Amt = CGF.EmitToMemory( EmitScalarConversion(OpInfo.RHS, E->getRHS()->getType(), LHSTy, E->getExprLoc()), LHSTy); Value *OldVal = Builder.CreateAtomicRMW( AtomicOp, LHSLV.getPointer(CGF), Amt, llvm::AtomicOrdering::SequentiallyConsistent); // Since operation is atomic, the result type is guaranteed to be the // same as the input in LLVM terms. Result = Builder.CreateBinOp(Op, OldVal, Amt); return LHSLV; } } // FIXME: For floating point types, we should be saving and restoring the // floating point environment in the loop. llvm::BasicBlock *startBB = Builder.GetInsertBlock(); llvm::BasicBlock *opBB = CGF.createBasicBlock("atomic_op", CGF.CurFn); OpInfo.LHS = EmitLoadOfLValue(LHSLV, E->getExprLoc()); OpInfo.LHS = CGF.EmitToMemory(OpInfo.LHS, type); Builder.CreateBr(opBB); Builder.SetInsertPoint(opBB); atomicPHI = Builder.CreatePHI(OpInfo.LHS->getType(), 2); atomicPHI->addIncoming(OpInfo.LHS, startBB); OpInfo.LHS = atomicPHI; } else OpInfo.LHS = EmitLoadOfLValue(LHSLV, E->getExprLoc()); CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, OpInfo.FPFeatures); SourceLocation Loc = E->getExprLoc(); OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, E->getComputationLHSType(), Loc); // Expand the binary operator. Result = (this->*Func)(OpInfo); // Convert the result back to the LHS type, // potentially with Implicit Conversion sanitizer check. Result = EmitScalarConversion(Result, E->getComputationResultType(), LHSTy, Loc, ScalarConversionOpts(CGF.SanOpts)); if (atomicPHI) { llvm::BasicBlock *curBlock = Builder.GetInsertBlock(); llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn); auto Pair = CGF.EmitAtomicCompareExchange( LHSLV, RValue::get(atomicPHI), RValue::get(Result), E->getExprLoc()); llvm::Value *old = CGF.EmitToMemory(Pair.first.getScalarVal(), LHSTy); llvm::Value *success = Pair.second; atomicPHI->addIncoming(old, curBlock); Builder.CreateCondBr(success, contBB, atomicPHI->getParent()); Builder.SetInsertPoint(contBB); return LHSLV; } // Store the result value into the LHS lvalue. Bit-fields are handled // specially because the result is altered by the store, i.e., [C99 6.5.16p1] // 'An assignment expression has the value of the left operand after the // assignment...'. if (LHSLV.isBitField()) CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, &Result); else CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV); if (CGF.getLangOpts().OpenMP) CGF.CGM.getOpenMPRuntime().checkAndEmitLastprivateConditional(CGF, E->getLHS()); return LHSLV; } Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E, Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) { bool Ignore = TestAndClearIgnoreResultAssign(); Value *RHS = nullptr; LValue LHS = EmitCompoundAssignLValue(E, Func, RHS); // If the result is clearly ignored, return now. if (Ignore) return nullptr; // The result of an assignment in C is the assigned r-value. if (!CGF.getLangOpts().CPlusPlus) return RHS; // If the lvalue is non-volatile, return the computed value of the assignment. if (!LHS.isVolatileQualified()) return RHS; // Otherwise, reload the value. return EmitLoadOfLValue(LHS, E->getExprLoc()); } void ScalarExprEmitter::EmitUndefinedBehaviorIntegerDivAndRemCheck( const BinOpInfo &Ops, llvm::Value *Zero, bool isDiv) { SmallVector, 2> Checks; if (CGF.SanOpts.has(SanitizerKind::IntegerDivideByZero)) { Checks.push_back(std::make_pair(Builder.CreateICmpNE(Ops.RHS, Zero), SanitizerKind::IntegerDivideByZero)); } const auto *BO = cast(Ops.E); if (CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow) && Ops.Ty->hasSignedIntegerRepresentation() && !IsWidenedIntegerOp(CGF.getContext(), BO->getLHS()) && Ops.mayHaveIntegerOverflow()) { llvm::IntegerType *Ty = cast(Zero->getType()); llvm::Value *IntMin = Builder.getInt(llvm::APInt::getSignedMinValue(Ty->getBitWidth())); llvm::Value *NegOne = llvm::ConstantInt::get(Ty, -1ULL); llvm::Value *LHSCmp = Builder.CreateICmpNE(Ops.LHS, IntMin); llvm::Value *RHSCmp = Builder.CreateICmpNE(Ops.RHS, NegOne); llvm::Value *NotOverflow = Builder.CreateOr(LHSCmp, RHSCmp, "or"); Checks.push_back( std::make_pair(NotOverflow, SanitizerKind::SignedIntegerOverflow)); } if (Checks.size() > 0) EmitBinOpCheck(Checks, Ops); } Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) { { CodeGenFunction::SanitizerScope SanScope(&CGF); if ((CGF.SanOpts.has(SanitizerKind::IntegerDivideByZero) || CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) && Ops.Ty->isIntegerType() && (Ops.mayHaveIntegerDivisionByZero() || Ops.mayHaveIntegerOverflow())) { llvm::Value *Zero = llvm::Constant::getNullValue(ConvertType(Ops.Ty)); EmitUndefinedBehaviorIntegerDivAndRemCheck(Ops, Zero, true); } else if (CGF.SanOpts.has(SanitizerKind::FloatDivideByZero) && Ops.Ty->isRealFloatingType() && Ops.mayHaveFloatDivisionByZero()) { llvm::Value *Zero = llvm::Constant::getNullValue(ConvertType(Ops.Ty)); llvm::Value *NonZero = Builder.CreateFCmpUNE(Ops.RHS, Zero); EmitBinOpCheck(std::make_pair(NonZero, SanitizerKind::FloatDivideByZero), Ops); } } if (Ops.LHS->getType()->isFPOrFPVectorTy()) { llvm::Value *Val; CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, Ops.FPFeatures); Val = Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div"); if (CGF.getLangOpts().OpenCL && !CGF.CGM.getCodeGenOpts().CorrectlyRoundedDivSqrt) { // OpenCL v1.1 s7.4: minimum accuracy of single precision / is 2.5ulp // OpenCL v1.2 s5.6.4.2: The -cl-fp32-correctly-rounded-divide-sqrt // build option allows an application to specify that single precision // floating-point divide (x/y and 1/x) and sqrt used in the program // source are correctly rounded. llvm::Type *ValTy = Val->getType(); if (ValTy->isFloatTy() || (isa(ValTy) && cast(ValTy)->getElementType()->isFloatTy())) CGF.SetFPAccuracy(Val, 2.5); } return Val; } else if (Ops.isFixedPointOp()) return EmitFixedPointBinOp(Ops); else if (Ops.Ty->hasUnsignedIntegerRepresentation()) return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div"); else return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div"); } Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) { // Rem in C can't be a floating point type: C99 6.5.5p2. if ((CGF.SanOpts.has(SanitizerKind::IntegerDivideByZero) || CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) && Ops.Ty->isIntegerType() && (Ops.mayHaveIntegerDivisionByZero() || Ops.mayHaveIntegerOverflow())) { CodeGenFunction::SanitizerScope SanScope(&CGF); llvm::Value *Zero = llvm::Constant::getNullValue(ConvertType(Ops.Ty)); EmitUndefinedBehaviorIntegerDivAndRemCheck(Ops, Zero, false); } if (Ops.Ty->hasUnsignedIntegerRepresentation()) return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem"); else return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem"); } Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) { unsigned IID; unsigned OpID = 0; SanitizerHandler OverflowKind; bool isSigned = Ops.Ty->isSignedIntegerOrEnumerationType(); switch (Ops.Opcode) { case BO_Add: case BO_AddAssign: OpID = 1; IID = isSigned ? llvm::Intrinsic::sadd_with_overflow : llvm::Intrinsic::uadd_with_overflow; OverflowKind = SanitizerHandler::AddOverflow; break; case BO_Sub: case BO_SubAssign: OpID = 2; IID = isSigned ? llvm::Intrinsic::ssub_with_overflow : llvm::Intrinsic::usub_with_overflow; OverflowKind = SanitizerHandler::SubOverflow; break; case BO_Mul: case BO_MulAssign: OpID = 3; IID = isSigned ? llvm::Intrinsic::smul_with_overflow : llvm::Intrinsic::umul_with_overflow; OverflowKind = SanitizerHandler::MulOverflow; break; default: llvm_unreachable("Unsupported operation for overflow detection"); } OpID <<= 1; if (isSigned) OpID |= 1; CodeGenFunction::SanitizerScope SanScope(&CGF); llvm::Type *opTy = CGF.CGM.getTypes().ConvertType(Ops.Ty); llvm::Function *intrinsic = CGF.CGM.getIntrinsic(IID, opTy); Value *resultAndOverflow = Builder.CreateCall(intrinsic, {Ops.LHS, Ops.RHS}); Value *result = Builder.CreateExtractValue(resultAndOverflow, 0); Value *overflow = Builder.CreateExtractValue(resultAndOverflow, 1); // Handle overflow with llvm.trap if no custom handler has been specified. const std::string *handlerName = &CGF.getLangOpts().OverflowHandler; if (handlerName->empty()) { // If the signed-integer-overflow sanitizer is enabled, emit a call to its // runtime. Otherwise, this is a -ftrapv check, so just emit a trap. if (!isSigned || CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) { llvm::Value *NotOverflow = Builder.CreateNot(overflow); SanitizerMask Kind = isSigned ? SanitizerKind::SignedIntegerOverflow : SanitizerKind::UnsignedIntegerOverflow; EmitBinOpCheck(std::make_pair(NotOverflow, Kind), Ops); } else CGF.EmitTrapCheck(Builder.CreateNot(overflow), OverflowKind); return result; } // Branch in case of overflow. llvm::BasicBlock *initialBB = Builder.GetInsertBlock(); llvm::BasicBlock *continueBB = CGF.createBasicBlock("nooverflow", CGF.CurFn, initialBB->getNextNode()); llvm::BasicBlock *overflowBB = CGF.createBasicBlock("overflow", CGF.CurFn); Builder.CreateCondBr(overflow, overflowBB, continueBB); // If an overflow handler is set, then we want to call it and then use its // result, if it returns. Builder.SetInsertPoint(overflowBB); // Get the overflow handler. llvm::Type *Int8Ty = CGF.Int8Ty; llvm::Type *argTypes[] = { CGF.Int64Ty, CGF.Int64Ty, Int8Ty, Int8Ty }; llvm::FunctionType *handlerTy = llvm::FunctionType::get(CGF.Int64Ty, argTypes, true); llvm::FunctionCallee handler = CGF.CGM.CreateRuntimeFunction(handlerTy, *handlerName); // Sign extend the args to 64-bit, so that we can use the same handler for // all types of overflow. llvm::Value *lhs = Builder.CreateSExt(Ops.LHS, CGF.Int64Ty); llvm::Value *rhs = Builder.CreateSExt(Ops.RHS, CGF.Int64Ty); // Call the handler with the two arguments, the operation, and the size of // the result. llvm::Value *handlerArgs[] = { lhs, rhs, Builder.getInt8(OpID), Builder.getInt8(cast(opTy)->getBitWidth()) }; llvm::Value *handlerResult = CGF.EmitNounwindRuntimeCall(handler, handlerArgs); // Truncate the result back to the desired size. handlerResult = Builder.CreateTrunc(handlerResult, opTy); Builder.CreateBr(continueBB); Builder.SetInsertPoint(continueBB); llvm::PHINode *phi = Builder.CreatePHI(opTy, 2); phi->addIncoming(result, initialBB); phi->addIncoming(handlerResult, overflowBB); return phi; } /// Emit pointer + index arithmetic. static Value *emitPointerArithmetic(CodeGenFunction &CGF, const BinOpInfo &op, bool isSubtraction) { // Must have binary (not unary) expr here. Unary pointer // increment/decrement doesn't use this path. const BinaryOperator *expr = cast(op.E); Value *pointer = op.LHS; Expr *pointerOperand = expr->getLHS(); Value *index = op.RHS; Expr *indexOperand = expr->getRHS(); // In a subtraction, the LHS is always the pointer. if (!isSubtraction && !pointer->getType()->isPointerTy()) { std::swap(pointer, index); std::swap(pointerOperand, indexOperand); } bool isSigned = indexOperand->getType()->isSignedIntegerOrEnumerationType(); unsigned width = cast(index->getType())->getBitWidth(); auto &DL = CGF.CGM.getDataLayout(); auto PtrTy = cast(pointer->getType()); // Some versions of glibc and gcc use idioms (particularly in their malloc // routines) that add a pointer-sized integer (known to be a pointer value) // to a null pointer in order to cast the value back to an integer or as // part of a pointer alignment algorithm. This is undefined behavior, but // we'd like to be able to compile programs that use it. // // Normally, we'd generate a GEP with a null-pointer base here in response // to that code, but it's also UB to dereference a pointer created that // way. Instead (as an acknowledged hack to tolerate the idiom) we will // generate a direct cast of the integer value to a pointer. // // The idiom (p = nullptr + N) is not met if any of the following are true: // // The operation is subtraction. // The index is not pointer-sized. // The pointer type is not byte-sized. // if (BinaryOperator::isNullPointerArithmeticExtension(CGF.getContext(), op.Opcode, expr->getLHS(), expr->getRHS())) return CGF.Builder.CreateIntToPtr(index, pointer->getType()); if (width != DL.getIndexTypeSizeInBits(PtrTy)) { // Zero-extend or sign-extend the pointer value according to // whether the index is signed or not. index = CGF.Builder.CreateIntCast(index, DL.getIndexType(PtrTy), isSigned, "idx.ext"); } // If this is subtraction, negate the index. if (isSubtraction) index = CGF.Builder.CreateNeg(index, "idx.neg"); if (CGF.SanOpts.has(SanitizerKind::ArrayBounds)) CGF.EmitBoundsCheck(op.E, pointerOperand, index, indexOperand->getType(), /*Accessed*/ false); const PointerType *pointerType = pointerOperand->getType()->getAs(); if (!pointerType) { QualType objectType = pointerOperand->getType() ->castAs() ->getPointeeType(); llvm::Value *objectSize = CGF.CGM.getSize(CGF.getContext().getTypeSizeInChars(objectType)); index = CGF.Builder.CreateMul(index, objectSize); Value *result = CGF.Builder.CreateBitCast(pointer, CGF.VoidPtrTy); result = CGF.Builder.CreateGEP(result, index, "add.ptr"); return CGF.Builder.CreateBitCast(result, pointer->getType()); } QualType elementType = pointerType->getPointeeType(); if (const VariableArrayType *vla = CGF.getContext().getAsVariableArrayType(elementType)) { // The element count here is the total number of non-VLA elements. llvm::Value *numElements = CGF.getVLASize(vla).NumElts; // Effectively, the multiply by the VLA size is part of the GEP. // GEP indexes are signed, and scaling an index isn't permitted to // signed-overflow, so we use the same semantics for our explicit // multiply. We suppress this if overflow is not undefined behavior. if (CGF.getLangOpts().isSignedOverflowDefined()) { index = CGF.Builder.CreateMul(index, numElements, "vla.index"); pointer = CGF.Builder.CreateGEP(pointer, index, "add.ptr"); } else { index = CGF.Builder.CreateNSWMul(index, numElements, "vla.index"); pointer = CGF.EmitCheckedInBoundsGEP(pointer, index, isSigned, isSubtraction, op.E->getExprLoc(), "add.ptr"); } return pointer; } // Explicitly handle GNU void* and function pointer arithmetic extensions. The // GNU void* casts amount to no-ops since our void* type is i8*, but this is // future proof. if (elementType->isVoidType() || elementType->isFunctionType()) { Value *result = CGF.EmitCastToVoidPtr(pointer); result = CGF.Builder.CreateGEP(result, index, "add.ptr"); return CGF.Builder.CreateBitCast(result, pointer->getType()); } if (CGF.getLangOpts().isSignedOverflowDefined()) return CGF.Builder.CreateGEP(pointer, index, "add.ptr"); return CGF.EmitCheckedInBoundsGEP(pointer, index, isSigned, isSubtraction, op.E->getExprLoc(), "add.ptr"); } // Construct an fmuladd intrinsic to represent a fused mul-add of MulOp and // Addend. Use negMul and negAdd to negate the first operand of the Mul or // the add operand respectively. This allows fmuladd to represent a*b-c, or // c-a*b. Patterns in LLVM should catch the negated forms and translate them to // efficient operations. static Value* buildFMulAdd(llvm::Instruction *MulOp, Value *Addend, const CodeGenFunction &CGF, CGBuilderTy &Builder, bool negMul, bool negAdd) { assert(!(negMul && negAdd) && "Only one of negMul and negAdd should be set."); Value *MulOp0 = MulOp->getOperand(0); Value *MulOp1 = MulOp->getOperand(1); if (negMul) MulOp0 = Builder.CreateFNeg(MulOp0, "neg"); if (negAdd) Addend = Builder.CreateFNeg(Addend, "neg"); Value *FMulAdd = nullptr; if (Builder.getIsFPConstrained()) { assert(isa(MulOp) && "Only constrained operation should be created when Builder is in FP " "constrained mode"); FMulAdd = Builder.CreateConstrainedFPCall( CGF.CGM.getIntrinsic(llvm::Intrinsic::experimental_constrained_fmuladd, Addend->getType()), {MulOp0, MulOp1, Addend}); } else { FMulAdd = Builder.CreateCall( CGF.CGM.getIntrinsic(llvm::Intrinsic::fmuladd, Addend->getType()), {MulOp0, MulOp1, Addend}); } MulOp->eraseFromParent(); return FMulAdd; } // Check whether it would be legal to emit an fmuladd intrinsic call to // represent op and if so, build the fmuladd. // // Checks that (a) the operation is fusable, and (b) -ffp-contract=on. // Does NOT check the type of the operation - it's assumed that this function // will be called from contexts where it's known that the type is contractable. static Value* tryEmitFMulAdd(const BinOpInfo &op, const CodeGenFunction &CGF, CGBuilderTy &Builder, bool isSub=false) { assert((op.Opcode == BO_Add || op.Opcode == BO_AddAssign || op.Opcode == BO_Sub || op.Opcode == BO_SubAssign) && "Only fadd/fsub can be the root of an fmuladd."); // Check whether this op is marked as fusable. if (!op.FPFeatures.allowFPContractWithinStatement()) return nullptr; // We have a potentially fusable op. Look for a mul on one of the operands. // Also, make sure that the mul result isn't used directly. In that case, // there's no point creating a muladd operation. if (auto *LHSBinOp = dyn_cast(op.LHS)) { if (LHSBinOp->getOpcode() == llvm::Instruction::FMul && LHSBinOp->use_empty()) return buildFMulAdd(LHSBinOp, op.RHS, CGF, Builder, false, isSub); } if (auto *RHSBinOp = dyn_cast(op.RHS)) { if (RHSBinOp->getOpcode() == llvm::Instruction::FMul && RHSBinOp->use_empty()) return buildFMulAdd(RHSBinOp, op.LHS, CGF, Builder, isSub, false); } if (auto *LHSBinOp = dyn_cast(op.LHS)) { if (LHSBinOp->getIntrinsicID() == llvm::Intrinsic::experimental_constrained_fmul && LHSBinOp->use_empty()) return buildFMulAdd(LHSBinOp, op.RHS, CGF, Builder, false, isSub); } if (auto *RHSBinOp = dyn_cast(op.RHS)) { if (RHSBinOp->getIntrinsicID() == llvm::Intrinsic::experimental_constrained_fmul && RHSBinOp->use_empty()) return buildFMulAdd(RHSBinOp, op.LHS, CGF, Builder, isSub, false); } return nullptr; } Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &op) { if (op.LHS->getType()->isPointerTy() || op.RHS->getType()->isPointerTy()) return emitPointerArithmetic(CGF, op, CodeGenFunction::NotSubtraction); if (op.Ty->isSignedIntegerOrEnumerationType()) { switch (CGF.getLangOpts().getSignedOverflowBehavior()) { case LangOptions::SOB_Defined: return Builder.CreateAdd(op.LHS, op.RHS, "add"); case LangOptions::SOB_Undefined: if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) return Builder.CreateNSWAdd(op.LHS, op.RHS, "add"); LLVM_FALLTHROUGH; case LangOptions::SOB_Trapping: if (CanElideOverflowCheck(CGF.getContext(), op)) return Builder.CreateNSWAdd(op.LHS, op.RHS, "add"); return EmitOverflowCheckedBinOp(op); } } if (op.Ty->isConstantMatrixType()) { llvm::MatrixBuilder MB(Builder); return MB.CreateAdd(op.LHS, op.RHS); } if (op.Ty->isUnsignedIntegerType() && CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) && !CanElideOverflowCheck(CGF.getContext(), op)) return EmitOverflowCheckedBinOp(op); if (op.LHS->getType()->isFPOrFPVectorTy()) { CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures); // Try to form an fmuladd. if (Value *FMulAdd = tryEmitFMulAdd(op, CGF, Builder)) return FMulAdd; return Builder.CreateFAdd(op.LHS, op.RHS, "add"); } if (op.isFixedPointOp()) return EmitFixedPointBinOp(op); return Builder.CreateAdd(op.LHS, op.RHS, "add"); } /// The resulting value must be calculated with exact precision, so the operands /// may not be the same type. Value *ScalarExprEmitter::EmitFixedPointBinOp(const BinOpInfo &op) { using llvm::APSInt; using llvm::ConstantInt; // This is either a binary operation where at least one of the operands is // a fixed-point type, or a unary operation where the operand is a fixed-point // type. The result type of a binary operation is determined by // Sema::handleFixedPointConversions(). QualType ResultTy = op.Ty; QualType LHSTy, RHSTy; if (const auto *BinOp = dyn_cast(op.E)) { RHSTy = BinOp->getRHS()->getType(); if (const auto *CAO = dyn_cast(BinOp)) { // For compound assignment, the effective type of the LHS at this point // is the computation LHS type, not the actual LHS type, and the final // result type is not the type of the expression but rather the // computation result type. LHSTy = CAO->getComputationLHSType(); ResultTy = CAO->getComputationResultType(); } else LHSTy = BinOp->getLHS()->getType(); } else if (const auto *UnOp = dyn_cast(op.E)) { LHSTy = UnOp->getSubExpr()->getType(); RHSTy = UnOp->getSubExpr()->getType(); } ASTContext &Ctx = CGF.getContext(); Value *LHS = op.LHS; Value *RHS = op.RHS; auto LHSFixedSema = Ctx.getFixedPointSemantics(LHSTy); auto RHSFixedSema = Ctx.getFixedPointSemantics(RHSTy); auto ResultFixedSema = Ctx.getFixedPointSemantics(ResultTy); auto CommonFixedSema = LHSFixedSema.getCommonSemantics(RHSFixedSema); // Perform the actual operation. Value *Result; llvm::FixedPointBuilder FPBuilder(Builder); switch (op.Opcode) { case BO_AddAssign: case BO_Add: Result = FPBuilder.CreateAdd(LHS, LHSFixedSema, RHS, RHSFixedSema); break; case BO_SubAssign: case BO_Sub: Result = FPBuilder.CreateSub(LHS, LHSFixedSema, RHS, RHSFixedSema); break; case BO_MulAssign: case BO_Mul: Result = FPBuilder.CreateMul(LHS, LHSFixedSema, RHS, RHSFixedSema); break; case BO_DivAssign: case BO_Div: Result = FPBuilder.CreateDiv(LHS, LHSFixedSema, RHS, RHSFixedSema); break; case BO_ShlAssign: case BO_Shl: Result = FPBuilder.CreateShl(LHS, LHSFixedSema, RHS); break; case BO_ShrAssign: case BO_Shr: Result = FPBuilder.CreateShr(LHS, LHSFixedSema, RHS); break; case BO_LT: return FPBuilder.CreateLT(LHS, LHSFixedSema, RHS, RHSFixedSema); case BO_GT: return FPBuilder.CreateGT(LHS, LHSFixedSema, RHS, RHSFixedSema); case BO_LE: return FPBuilder.CreateLE(LHS, LHSFixedSema, RHS, RHSFixedSema); case BO_GE: return FPBuilder.CreateGE(LHS, LHSFixedSema, RHS, RHSFixedSema); case BO_EQ: // For equality operations, we assume any padding bits on unsigned types are // zero'd out. They could be overwritten through non-saturating operations // that cause overflow, but this leads to undefined behavior. return FPBuilder.CreateEQ(LHS, LHSFixedSema, RHS, RHSFixedSema); case BO_NE: return FPBuilder.CreateNE(LHS, LHSFixedSema, RHS, RHSFixedSema); case BO_Cmp: case BO_LAnd: case BO_LOr: llvm_unreachable("Found unimplemented fixed point binary operation"); case BO_PtrMemD: case BO_PtrMemI: case BO_Rem: case BO_Xor: case BO_And: case BO_Or: case BO_Assign: case BO_RemAssign: case BO_AndAssign: case BO_XorAssign: case BO_OrAssign: case BO_Comma: llvm_unreachable("Found unsupported binary operation for fixed point types."); } bool IsShift = BinaryOperator::isShiftOp(op.Opcode) || BinaryOperator::isShiftAssignOp(op.Opcode); // Convert to the result type. return FPBuilder.CreateFixedToFixed(Result, IsShift ? LHSFixedSema : CommonFixedSema, ResultFixedSema); } Value *ScalarExprEmitter::EmitSub(const BinOpInfo &op) { // The LHS is always a pointer if either side is. if (!op.LHS->getType()->isPointerTy()) { if (op.Ty->isSignedIntegerOrEnumerationType()) { switch (CGF.getLangOpts().getSignedOverflowBehavior()) { case LangOptions::SOB_Defined: return Builder.CreateSub(op.LHS, op.RHS, "sub"); case LangOptions::SOB_Undefined: if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) return Builder.CreateNSWSub(op.LHS, op.RHS, "sub"); LLVM_FALLTHROUGH; case LangOptions::SOB_Trapping: if (CanElideOverflowCheck(CGF.getContext(), op)) return Builder.CreateNSWSub(op.LHS, op.RHS, "sub"); return EmitOverflowCheckedBinOp(op); } } if (op.Ty->isConstantMatrixType()) { llvm::MatrixBuilder MB(Builder); return MB.CreateSub(op.LHS, op.RHS); } if (op.Ty->isUnsignedIntegerType() && CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) && !CanElideOverflowCheck(CGF.getContext(), op)) return EmitOverflowCheckedBinOp(op); if (op.LHS->getType()->isFPOrFPVectorTy()) { CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures); // Try to form an fmuladd. if (Value *FMulAdd = tryEmitFMulAdd(op, CGF, Builder, true)) return FMulAdd; return Builder.CreateFSub(op.LHS, op.RHS, "sub"); } if (op.isFixedPointOp()) return EmitFixedPointBinOp(op); return Builder.CreateSub(op.LHS, op.RHS, "sub"); } // If the RHS is not a pointer, then we have normal pointer // arithmetic. if (!op.RHS->getType()->isPointerTy()) return emitPointerArithmetic(CGF, op, CodeGenFunction::IsSubtraction); // Otherwise, this is a pointer subtraction. // Do the raw subtraction part. llvm::Value *LHS = Builder.CreatePtrToInt(op.LHS, CGF.PtrDiffTy, "sub.ptr.lhs.cast"); llvm::Value *RHS = Builder.CreatePtrToInt(op.RHS, CGF.PtrDiffTy, "sub.ptr.rhs.cast"); Value *diffInChars = Builder.CreateSub(LHS, RHS, "sub.ptr.sub"); // Okay, figure out the element size. const BinaryOperator *expr = cast(op.E); QualType elementType = expr->getLHS()->getType()->getPointeeType(); llvm::Value *divisor = nullptr; // For a variable-length array, this is going to be non-constant. if (const VariableArrayType *vla = CGF.getContext().getAsVariableArrayType(elementType)) { auto VlaSize = CGF.getVLASize(vla); elementType = VlaSize.Type; divisor = VlaSize.NumElts; // Scale the number of non-VLA elements by the non-VLA element size. CharUnits eltSize = CGF.getContext().getTypeSizeInChars(elementType); if (!eltSize.isOne()) divisor = CGF.Builder.CreateNUWMul(CGF.CGM.getSize(eltSize), divisor); // For everything elese, we can just compute it, safe in the // assumption that Sema won't let anything through that we can't // safely compute the size of. } else { CharUnits elementSize; // Handle GCC extension for pointer arithmetic on void* and // function pointer types. if (elementType->isVoidType() || elementType->isFunctionType()) elementSize = CharUnits::One(); else elementSize = CGF.getContext().getTypeSizeInChars(elementType); // Don't even emit the divide for element size of 1. if (elementSize.isOne()) return diffInChars; divisor = CGF.CGM.getSize(elementSize); } // Otherwise, do a full sdiv. This uses the "exact" form of sdiv, since // pointer difference in C is only defined in the case where both operands // are pointing to elements of an array. return Builder.CreateExactSDiv(diffInChars, divisor, "sub.ptr.div"); } Value *ScalarExprEmitter::GetWidthMinusOneValue(Value* LHS,Value* RHS) { llvm::IntegerType *Ty; if (llvm::VectorType *VT = dyn_cast(LHS->getType())) Ty = cast(VT->getElementType()); else Ty = cast(LHS->getType()); return llvm::ConstantInt::get(RHS->getType(), Ty->getBitWidth() - 1); } Value *ScalarExprEmitter::ConstrainShiftValue(Value *LHS, Value *RHS, const Twine &Name) { llvm::IntegerType *Ty; if (auto *VT = dyn_cast(LHS->getType())) Ty = cast(VT->getElementType()); else Ty = cast(LHS->getType()); if (llvm::isPowerOf2_64(Ty->getBitWidth())) return Builder.CreateAnd(RHS, GetWidthMinusOneValue(LHS, RHS), Name); return Builder.CreateURem( RHS, llvm::ConstantInt::get(RHS->getType(), Ty->getBitWidth()), Name); } Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { // TODO: This misses out on the sanitizer check below. if (Ops.isFixedPointOp()) return EmitFixedPointBinOp(Ops); // LLVM requires the LHS and RHS to be the same type: promote or truncate the // RHS to the same size as the LHS. Value *RHS = Ops.RHS; if (Ops.LHS->getType() != RHS->getType()) RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); bool SanitizeSignedBase = CGF.SanOpts.has(SanitizerKind::ShiftBase) && Ops.Ty->hasSignedIntegerRepresentation() && !CGF.getLangOpts().isSignedOverflowDefined() && !CGF.getLangOpts().CPlusPlus20; bool SanitizeUnsignedBase = CGF.SanOpts.has(SanitizerKind::UnsignedShiftBase) && Ops.Ty->hasUnsignedIntegerRepresentation(); bool SanitizeBase = SanitizeSignedBase || SanitizeUnsignedBase; bool SanitizeExponent = CGF.SanOpts.has(SanitizerKind::ShiftExponent); // OpenCL 6.3j: shift values are effectively % word size of LHS. if (CGF.getLangOpts().OpenCL) RHS = ConstrainShiftValue(Ops.LHS, RHS, "shl.mask"); else if ((SanitizeBase || SanitizeExponent) && isa(Ops.LHS->getType())) { CodeGenFunction::SanitizerScope SanScope(&CGF); SmallVector, 2> Checks; llvm::Value *WidthMinusOne = GetWidthMinusOneValue(Ops.LHS, Ops.RHS); llvm::Value *ValidExponent = Builder.CreateICmpULE(Ops.RHS, WidthMinusOne); if (SanitizeExponent) { Checks.push_back( std::make_pair(ValidExponent, SanitizerKind::ShiftExponent)); } if (SanitizeBase) { // Check whether we are shifting any non-zero bits off the top of the // integer. We only emit this check if exponent is valid - otherwise // instructions below will have undefined behavior themselves. llvm::BasicBlock *Orig = Builder.GetInsertBlock(); llvm::BasicBlock *Cont = CGF.createBasicBlock("cont"); llvm::BasicBlock *CheckShiftBase = CGF.createBasicBlock("check"); Builder.CreateCondBr(ValidExponent, CheckShiftBase, Cont); llvm::Value *PromotedWidthMinusOne = (RHS == Ops.RHS) ? WidthMinusOne : GetWidthMinusOneValue(Ops.LHS, RHS); CGF.EmitBlock(CheckShiftBase); llvm::Value *BitsShiftedOff = Builder.CreateLShr( Ops.LHS, Builder.CreateSub(PromotedWidthMinusOne, RHS, "shl.zeros", /*NUW*/ true, /*NSW*/ true), "shl.check"); if (SanitizeUnsignedBase || CGF.getLangOpts().CPlusPlus) { // In C99, we are not permitted to shift a 1 bit into the sign bit. // Under C++11's rules, shifting a 1 bit into the sign bit is // OK, but shifting a 1 bit out of it is not. (C89 and C++03 don't // define signed left shifts, so we use the C99 and C++11 rules there). // Unsigned shifts can always shift into the top bit. llvm::Value *One = llvm::ConstantInt::get(BitsShiftedOff->getType(), 1); BitsShiftedOff = Builder.CreateLShr(BitsShiftedOff, One); } llvm::Value *Zero = llvm::ConstantInt::get(BitsShiftedOff->getType(), 0); llvm::Value *ValidBase = Builder.CreateICmpEQ(BitsShiftedOff, Zero); CGF.EmitBlock(Cont); llvm::PHINode *BaseCheck = Builder.CreatePHI(ValidBase->getType(), 2); BaseCheck->addIncoming(Builder.getTrue(), Orig); BaseCheck->addIncoming(ValidBase, CheckShiftBase); Checks.push_back(std::make_pair( BaseCheck, SanitizeSignedBase ? SanitizerKind::ShiftBase : SanitizerKind::UnsignedShiftBase)); } assert(!Checks.empty()); EmitBinOpCheck(Checks, Ops); } return Builder.CreateShl(Ops.LHS, RHS, "shl"); } Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) { // TODO: This misses out on the sanitizer check below. if (Ops.isFixedPointOp()) return EmitFixedPointBinOp(Ops); // LLVM requires the LHS and RHS to be the same type: promote or truncate the // RHS to the same size as the LHS. Value *RHS = Ops.RHS; if (Ops.LHS->getType() != RHS->getType()) RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); // OpenCL 6.3j: shift values are effectively % word size of LHS. if (CGF.getLangOpts().OpenCL) RHS = ConstrainShiftValue(Ops.LHS, RHS, "shr.mask"); else if (CGF.SanOpts.has(SanitizerKind::ShiftExponent) && isa(Ops.LHS->getType())) { CodeGenFunction::SanitizerScope SanScope(&CGF); llvm::Value *Valid = Builder.CreateICmpULE(RHS, GetWidthMinusOneValue(Ops.LHS, RHS)); EmitBinOpCheck(std::make_pair(Valid, SanitizerKind::ShiftExponent), Ops); } if (Ops.Ty->hasUnsignedIntegerRepresentation()) return Builder.CreateLShr(Ops.LHS, RHS, "shr"); return Builder.CreateAShr(Ops.LHS, RHS, "shr"); } enum IntrinsicType { VCMPEQ, VCMPGT }; // return corresponding comparison intrinsic for given vector type static llvm::Intrinsic::ID GetIntrinsic(IntrinsicType IT, BuiltinType::Kind ElemKind) { switch (ElemKind) { default: llvm_unreachable("unexpected element type"); case BuiltinType::Char_U: case BuiltinType::UChar: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequb_p : llvm::Intrinsic::ppc_altivec_vcmpgtub_p; case BuiltinType::Char_S: case BuiltinType::SChar: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequb_p : llvm::Intrinsic::ppc_altivec_vcmpgtsb_p; case BuiltinType::UShort: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequh_p : llvm::Intrinsic::ppc_altivec_vcmpgtuh_p; case BuiltinType::Short: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequh_p : llvm::Intrinsic::ppc_altivec_vcmpgtsh_p; case BuiltinType::UInt: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequw_p : llvm::Intrinsic::ppc_altivec_vcmpgtuw_p; case BuiltinType::Int: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequw_p : llvm::Intrinsic::ppc_altivec_vcmpgtsw_p; case BuiltinType::ULong: case BuiltinType::ULongLong: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequd_p : llvm::Intrinsic::ppc_altivec_vcmpgtud_p; case BuiltinType::Long: case BuiltinType::LongLong: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequd_p : llvm::Intrinsic::ppc_altivec_vcmpgtsd_p; case BuiltinType::Float: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpeqfp_p : llvm::Intrinsic::ppc_altivec_vcmpgtfp_p; case BuiltinType::Double: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_vsx_xvcmpeqdp_p : llvm::Intrinsic::ppc_vsx_xvcmpgtdp_p; case BuiltinType::UInt128: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequq_p : llvm::Intrinsic::ppc_altivec_vcmpgtuq_p; case BuiltinType::Int128: return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequq_p : llvm::Intrinsic::ppc_altivec_vcmpgtsq_p; } } Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E, llvm::CmpInst::Predicate UICmpOpc, llvm::CmpInst::Predicate SICmpOpc, llvm::CmpInst::Predicate FCmpOpc, bool IsSignaling) { TestAndClearIgnoreResultAssign(); Value *Result; QualType LHSTy = E->getLHS()->getType(); QualType RHSTy = E->getRHS()->getType(); if (const MemberPointerType *MPT = LHSTy->getAs()) { assert(E->getOpcode() == BO_EQ || E->getOpcode() == BO_NE); Value *LHS = CGF.EmitScalarExpr(E->getLHS()); Value *RHS = CGF.EmitScalarExpr(E->getRHS()); Result = CGF.CGM.getCXXABI().EmitMemberPointerComparison( CGF, LHS, RHS, MPT, E->getOpcode() == BO_NE); } else if (!LHSTy->isAnyComplexType() && !RHSTy->isAnyComplexType()) { BinOpInfo BOInfo = EmitBinOps(E); Value *LHS = BOInfo.LHS; Value *RHS = BOInfo.RHS; // If AltiVec, the comparison results in a numeric type, so we use // intrinsics comparing vectors and giving 0 or 1 as a result if (LHSTy->isVectorType() && !E->getType()->isVectorType()) { // constants for mapping CR6 register bits to predicate result enum { CR6_EQ=0, CR6_EQ_REV, CR6_LT, CR6_LT_REV } CR6; llvm::Intrinsic::ID ID = llvm::Intrinsic::not_intrinsic; // in several cases vector arguments order will be reversed Value *FirstVecArg = LHS, *SecondVecArg = RHS; QualType ElTy = LHSTy->castAs()->getElementType(); BuiltinType::Kind ElementKind = ElTy->castAs()->getKind(); switch(E->getOpcode()) { default: llvm_unreachable("is not a comparison operation"); case BO_EQ: CR6 = CR6_LT; ID = GetIntrinsic(VCMPEQ, ElementKind); break; case BO_NE: CR6 = CR6_EQ; ID = GetIntrinsic(VCMPEQ, ElementKind); break; case BO_LT: CR6 = CR6_LT; ID = GetIntrinsic(VCMPGT, ElementKind); std::swap(FirstVecArg, SecondVecArg); break; case BO_GT: CR6 = CR6_LT; ID = GetIntrinsic(VCMPGT, ElementKind); break; case BO_LE: if (ElementKind == BuiltinType::Float) { CR6 = CR6_LT; ID = llvm::Intrinsic::ppc_altivec_vcmpgefp_p; std::swap(FirstVecArg, SecondVecArg); } else { CR6 = CR6_EQ; ID = GetIntrinsic(VCMPGT, ElementKind); } break; case BO_GE: if (ElementKind == BuiltinType::Float) { CR6 = CR6_LT; ID = llvm::Intrinsic::ppc_altivec_vcmpgefp_p; } else { CR6 = CR6_EQ; ID = GetIntrinsic(VCMPGT, ElementKind); std::swap(FirstVecArg, SecondVecArg); } break; } Value *CR6Param = Builder.getInt32(CR6); llvm::Function *F = CGF.CGM.getIntrinsic(ID); Result = Builder.CreateCall(F, {CR6Param, FirstVecArg, SecondVecArg}); // The result type of intrinsic may not be same as E->getType(). // If E->getType() is not BoolTy, EmitScalarConversion will do the // conversion work. If E->getType() is BoolTy, EmitScalarConversion will // do nothing, if ResultTy is not i1 at the same time, it will cause // crash later. llvm::IntegerType *ResultTy = cast(Result->getType()); if (ResultTy->getBitWidth() > 1 && E->getType() == CGF.getContext().BoolTy) Result = Builder.CreateTrunc(Result, Builder.getInt1Ty()); return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType(), E->getExprLoc()); } if (BOInfo.isFixedPointOp()) { Result = EmitFixedPointBinOp(BOInfo); } else if (LHS->getType()->isFPOrFPVectorTy()) { CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, BOInfo.FPFeatures); if (!IsSignaling) Result = Builder.CreateFCmp(FCmpOpc, LHS, RHS, "cmp"); else Result = Builder.CreateFCmpS(FCmpOpc, LHS, RHS, "cmp"); } else if (LHSTy->hasSignedIntegerRepresentation()) { Result = Builder.CreateICmp(SICmpOpc, LHS, RHS, "cmp"); } else { // Unsigned integers and pointers. if (CGF.CGM.getCodeGenOpts().StrictVTablePointers && !isa(LHS) && !isa(RHS)) { // Dynamic information is required to be stripped for comparisons, // because it could leak the dynamic information. Based on comparisons // of pointers to dynamic objects, the optimizer can replace one pointer // with another, which might be incorrect in presence of invariant // groups. Comparison with null is safe because null does not carry any // dynamic information. if (LHSTy.mayBeDynamicClass()) LHS = Builder.CreateStripInvariantGroup(LHS); if (RHSTy.mayBeDynamicClass()) RHS = Builder.CreateStripInvariantGroup(RHS); } Result = Builder.CreateICmp(UICmpOpc, LHS, RHS, "cmp"); } // If this is a vector comparison, sign extend the result to the appropriate // vector integer type and return it (don't convert to bool). if (LHSTy->isVectorType()) return Builder.CreateSExt(Result, ConvertType(E->getType()), "sext"); } else { // Complex Comparison: can only be an equality comparison. CodeGenFunction::ComplexPairTy LHS, RHS; QualType CETy; if (auto *CTy = LHSTy->getAs()) { LHS = CGF.EmitComplexExpr(E->getLHS()); CETy = CTy->getElementType(); } else { LHS.first = Visit(E->getLHS()); LHS.second = llvm::Constant::getNullValue(LHS.first->getType()); CETy = LHSTy; } if (auto *CTy = RHSTy->getAs()) { RHS = CGF.EmitComplexExpr(E->getRHS()); assert(CGF.getContext().hasSameUnqualifiedType(CETy, CTy->getElementType()) && "The element types must always match."); (void)CTy; } else { RHS.first = Visit(E->getRHS()); RHS.second = llvm::Constant::getNullValue(RHS.first->getType()); assert(CGF.getContext().hasSameUnqualifiedType(CETy, RHSTy) && "The element types must always match."); } Value *ResultR, *ResultI; if (CETy->isRealFloatingType()) { // As complex comparisons can only be equality comparisons, they // are never signaling comparisons. ResultR = Builder.CreateFCmp(FCmpOpc, LHS.first, RHS.first, "cmp.r"); ResultI = Builder.CreateFCmp(FCmpOpc, LHS.second, RHS.second, "cmp.i"); } else { // Complex comparisons can only be equality comparisons. As such, signed // and unsigned opcodes are the same. ResultR = Builder.CreateICmp(UICmpOpc, LHS.first, RHS.first, "cmp.r"); ResultI = Builder.CreateICmp(UICmpOpc, LHS.second, RHS.second, "cmp.i"); } if (E->getOpcode() == BO_EQ) { Result = Builder.CreateAnd(ResultR, ResultI, "and.ri"); } else { assert(E->getOpcode() == BO_NE && "Complex comparison other than == or != ?"); Result = Builder.CreateOr(ResultR, ResultI, "or.ri"); } } return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType(), E->getExprLoc()); } Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) { bool Ignore = TestAndClearIgnoreResultAssign(); Value *RHS; LValue LHS; switch (E->getLHS()->getType().getObjCLifetime()) { case Qualifiers::OCL_Strong: std::tie(LHS, RHS) = CGF.EmitARCStoreStrong(E, Ignore); break; case Qualifiers::OCL_Autoreleasing: std::tie(LHS, RHS) = CGF.EmitARCStoreAutoreleasing(E); break; case Qualifiers::OCL_ExplicitNone: std::tie(LHS, RHS) = CGF.EmitARCStoreUnsafeUnretained(E, Ignore); break; case Qualifiers::OCL_Weak: RHS = Visit(E->getRHS()); LHS = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store); RHS = CGF.EmitARCStoreWeak(LHS.getAddress(CGF), RHS, Ignore); break; case Qualifiers::OCL_None: // __block variables need to have the rhs evaluated first, plus // this should improve codegen just a little. RHS = Visit(E->getRHS()); LHS = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store); // Store the value into the LHS. Bit-fields are handled specially // because the result is altered by the store, i.e., [C99 6.5.16p1] // 'An assignment expression has the value of the left operand after // the assignment...'. if (LHS.isBitField()) { CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, &RHS); } else { CGF.EmitNullabilityCheck(LHS, RHS, E->getExprLoc()); CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS); } } // If the result is clearly ignored, return now. if (Ignore) return nullptr; // The result of an assignment in C is the assigned r-value. if (!CGF.getLangOpts().CPlusPlus) return RHS; // If the lvalue is non-volatile, return the computed value of the assignment. if (!LHS.isVolatileQualified()) return RHS; // Otherwise, reload the value. return EmitLoadOfLValue(LHS, E->getExprLoc()); } Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) { // Perform vector logical and on comparisons with zero vectors. if (E->getType()->isVectorType()) { CGF.incrementProfileCounter(E); Value *LHS = Visit(E->getLHS()); Value *RHS = Visit(E->getRHS()); Value *Zero = llvm::ConstantAggregateZero::get(LHS->getType()); if (LHS->getType()->isFPOrFPVectorTy()) { CodeGenFunction::CGFPOptionsRAII FPOptsRAII( CGF, E->getFPFeaturesInEffect(CGF.getLangOpts())); LHS = Builder.CreateFCmp(llvm::CmpInst::FCMP_UNE, LHS, Zero, "cmp"); RHS = Builder.CreateFCmp(llvm::CmpInst::FCMP_UNE, RHS, Zero, "cmp"); } else { LHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, LHS, Zero, "cmp"); RHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, RHS, Zero, "cmp"); } Value *And = Builder.CreateAnd(LHS, RHS); return Builder.CreateSExt(And, ConvertType(E->getType()), "sext"); } bool InstrumentRegions = CGF.CGM.getCodeGenOpts().hasProfileClangInstr(); llvm::Type *ResTy = ConvertType(E->getType()); // If we have 0 && RHS, see if we can elide RHS, if so, just return 0. // If we have 1 && X, just emit X without inserting the control flow. bool LHSCondVal; if (CGF.ConstantFoldsToSimpleInteger(E->getLHS(), LHSCondVal)) { if (LHSCondVal) { // If we have 1 && X, just emit X. CGF.incrementProfileCounter(E); Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); // If we're generating for profiling or coverage, generate a branch to a // block that increments the RHS counter needed to track branch condition // coverage. In this case, use "FBlock" as both the final "TrueBlock" and // "FalseBlock" after the increment is done. if (InstrumentRegions && CodeGenFunction::isInstrumentedCondition(E->getRHS())) { llvm::BasicBlock *FBlock = CGF.createBasicBlock("land.end"); llvm::BasicBlock *RHSBlockCnt = CGF.createBasicBlock("land.rhscnt"); Builder.CreateCondBr(RHSCond, RHSBlockCnt, FBlock); CGF.EmitBlock(RHSBlockCnt); CGF.incrementProfileCounter(E->getRHS()); CGF.EmitBranch(FBlock); CGF.EmitBlock(FBlock); } // ZExt result to int or bool. return Builder.CreateZExtOrBitCast(RHSCond, ResTy, "land.ext"); } // 0 && RHS: If it is safe, just elide the RHS, and return 0/false. if (!CGF.ContainsLabel(E->getRHS())) return llvm::Constant::getNullValue(ResTy); } llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end"); llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("land.rhs"); CodeGenFunction::ConditionalEvaluation eval(CGF); // Branch on the LHS first. If it is false, go to the failure (cont) block. CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock, CGF.getProfileCount(E->getRHS())); // Any edges into the ContBlock are now from an (indeterminate number of) // edges from this first condition. All of these values will be false. Start // setting up the PHI node in the Cont Block for this. llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::getInt1Ty(VMContext), 2, "", ContBlock); for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); PI != PE; ++PI) PN->addIncoming(llvm::ConstantInt::getFalse(VMContext), *PI); eval.begin(CGF); CGF.EmitBlock(RHSBlock); CGF.incrementProfileCounter(E); Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); eval.end(CGF); // Reaquire the RHS block, as there may be subblocks inserted. RHSBlock = Builder.GetInsertBlock(); // If we're generating for profiling or coverage, generate a branch on the // RHS to a block that increments the RHS true counter needed to track branch // condition coverage. if (InstrumentRegions && CodeGenFunction::isInstrumentedCondition(E->getRHS())) { llvm::BasicBlock *RHSBlockCnt = CGF.createBasicBlock("land.rhscnt"); Builder.CreateCondBr(RHSCond, RHSBlockCnt, ContBlock); CGF.EmitBlock(RHSBlockCnt); CGF.incrementProfileCounter(E->getRHS()); CGF.EmitBranch(ContBlock); PN->addIncoming(RHSCond, RHSBlockCnt); } // Emit an unconditional branch from this block to ContBlock. { // There is no need to emit line number for unconditional branch. auto NL = ApplyDebugLocation::CreateEmpty(CGF); CGF.EmitBlock(ContBlock); } // Insert an entry into the phi node for the edge with the value of RHSCond. PN->addIncoming(RHSCond, RHSBlock); // Artificial location to preserve the scope information { auto NL = ApplyDebugLocation::CreateArtificial(CGF); PN->setDebugLoc(Builder.getCurrentDebugLocation()); } // ZExt result to int. return Builder.CreateZExtOrBitCast(PN, ResTy, "land.ext"); } Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) { // Perform vector logical or on comparisons with zero vectors. if (E->getType()->isVectorType()) { CGF.incrementProfileCounter(E); Value *LHS = Visit(E->getLHS()); Value *RHS = Visit(E->getRHS()); Value *Zero = llvm::ConstantAggregateZero::get(LHS->getType()); if (LHS->getType()->isFPOrFPVectorTy()) { CodeGenFunction::CGFPOptionsRAII FPOptsRAII( CGF, E->getFPFeaturesInEffect(CGF.getLangOpts())); LHS = Builder.CreateFCmp(llvm::CmpInst::FCMP_UNE, LHS, Zero, "cmp"); RHS = Builder.CreateFCmp(llvm::CmpInst::FCMP_UNE, RHS, Zero, "cmp"); } else { LHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, LHS, Zero, "cmp"); RHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, RHS, Zero, "cmp"); } Value *Or = Builder.CreateOr(LHS, RHS); return Builder.CreateSExt(Or, ConvertType(E->getType()), "sext"); } bool InstrumentRegions = CGF.CGM.getCodeGenOpts().hasProfileClangInstr(); llvm::Type *ResTy = ConvertType(E->getType()); // If we have 1 || RHS, see if we can elide RHS, if so, just return 1. // If we have 0 || X, just emit X without inserting the control flow. bool LHSCondVal; if (CGF.ConstantFoldsToSimpleInteger(E->getLHS(), LHSCondVal)) { if (!LHSCondVal) { // If we have 0 || X, just emit X. CGF.incrementProfileCounter(E); Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); // If we're generating for profiling or coverage, generate a branch to a // block that increments the RHS counter need to track branch condition // coverage. In this case, use "FBlock" as both the final "TrueBlock" and // "FalseBlock" after the increment is done. if (InstrumentRegions && CodeGenFunction::isInstrumentedCondition(E->getRHS())) { llvm::BasicBlock *FBlock = CGF.createBasicBlock("lor.end"); llvm::BasicBlock *RHSBlockCnt = CGF.createBasicBlock("lor.rhscnt"); Builder.CreateCondBr(RHSCond, FBlock, RHSBlockCnt); CGF.EmitBlock(RHSBlockCnt); CGF.incrementProfileCounter(E->getRHS()); CGF.EmitBranch(FBlock); CGF.EmitBlock(FBlock); } // ZExt result to int or bool. return Builder.CreateZExtOrBitCast(RHSCond, ResTy, "lor.ext"); } // 1 || RHS: If it is safe, just elide the RHS, and return 1/true. if (!CGF.ContainsLabel(E->getRHS())) return llvm::ConstantInt::get(ResTy, 1); } llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end"); llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs"); CodeGenFunction::ConditionalEvaluation eval(CGF); // Branch on the LHS first. If it is true, go to the success (cont) block. CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock, CGF.getCurrentProfileCount() - CGF.getProfileCount(E->getRHS())); // Any edges into the ContBlock are now from an (indeterminate number of) // edges from this first condition. All of these values will be true. Start // setting up the PHI node in the Cont Block for this. llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::getInt1Ty(VMContext), 2, "", ContBlock); for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); PI != PE; ++PI) PN->addIncoming(llvm::ConstantInt::getTrue(VMContext), *PI); eval.begin(CGF); // Emit the RHS condition as a bool value. CGF.EmitBlock(RHSBlock); CGF.incrementProfileCounter(E); Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); eval.end(CGF); // Reaquire the RHS block, as there may be subblocks inserted. RHSBlock = Builder.GetInsertBlock(); // If we're generating for profiling or coverage, generate a branch on the // RHS to a block that increments the RHS true counter needed to track branch // condition coverage. if (InstrumentRegions && CodeGenFunction::isInstrumentedCondition(E->getRHS())) { llvm::BasicBlock *RHSBlockCnt = CGF.createBasicBlock("lor.rhscnt"); Builder.CreateCondBr(RHSCond, ContBlock, RHSBlockCnt); CGF.EmitBlock(RHSBlockCnt); CGF.incrementProfileCounter(E->getRHS()); CGF.EmitBranch(ContBlock); PN->addIncoming(RHSCond, RHSBlockCnt); } // Emit an unconditional branch from this block to ContBlock. Insert an entry // into the phi node for the edge with the value of RHSCond. CGF.EmitBlock(ContBlock); PN->addIncoming(RHSCond, RHSBlock); // ZExt result to int. return Builder.CreateZExtOrBitCast(PN, ResTy, "lor.ext"); } Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) { CGF.EmitIgnoredExpr(E->getLHS()); CGF.EnsureInsertPoint(); return Visit(E->getRHS()); } //===----------------------------------------------------------------------===// // Other Operators //===----------------------------------------------------------------------===// /// isCheapEnoughToEvaluateUnconditionally - Return true if the specified /// expression is cheap enough and side-effect-free enough to evaluate /// unconditionally instead of conditionally. This is used to convert control /// flow into selects in some cases. static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E, CodeGenFunction &CGF) { // Anything that is an integer or floating point constant is fine. return E->IgnoreParens()->isEvaluatable(CGF.getContext()); // Even non-volatile automatic variables can't be evaluated unconditionally. // Referencing a thread_local may cause non-trivial initialization work to // occur. If we're inside a lambda and one of the variables is from the scope // outside the lambda, that function may have returned already. Reading its // locals is a bad idea. Also, these reads may introduce races there didn't // exist in the source-level program. } Value *ScalarExprEmitter:: VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) { TestAndClearIgnoreResultAssign(); // Bind the common expression if necessary. CodeGenFunction::OpaqueValueMapping binding(CGF, E); Expr *condExpr = E->getCond(); Expr *lhsExpr = E->getTrueExpr(); Expr *rhsExpr = E->getFalseExpr(); // If the condition constant folds and can be elided, try to avoid emitting // the condition and the dead arm. bool CondExprBool; if (CGF.ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) { Expr *live = lhsExpr, *dead = rhsExpr; if (!CondExprBool) std::swap(live, dead); // If the dead side doesn't have labels we need, just emit the Live part. if (!CGF.ContainsLabel(dead)) { if (CondExprBool) CGF.incrementProfileCounter(E); Value *Result = Visit(live); // If the live part is a throw expression, it acts like it has a void // type, so evaluating it returns a null Value*. However, a conditional // with non-void type must return a non-null Value*. if (!Result && !E->getType()->isVoidType()) Result = llvm::UndefValue::get(CGF.ConvertType(E->getType())); return Result; } } // OpenCL: If the condition is a vector, we can treat this condition like // the select function. if ((CGF.getLangOpts().OpenCL && condExpr->getType()->isVectorType()) || condExpr->getType()->isExtVectorType()) { CGF.incrementProfileCounter(E); llvm::Value *CondV = CGF.EmitScalarExpr(condExpr); llvm::Value *LHS = Visit(lhsExpr); llvm::Value *RHS = Visit(rhsExpr); llvm::Type *condType = ConvertType(condExpr->getType()); auto *vecTy = cast(condType); unsigned numElem = vecTy->getNumElements(); llvm::Type *elemType = vecTy->getElementType(); llvm::Value *zeroVec = llvm::Constant::getNullValue(vecTy); llvm::Value *TestMSB = Builder.CreateICmpSLT(CondV, zeroVec); llvm::Value *tmp = Builder.CreateSExt( TestMSB, llvm::FixedVectorType::get(elemType, numElem), "sext"); llvm::Value *tmp2 = Builder.CreateNot(tmp); // Cast float to int to perform ANDs if necessary. llvm::Value *RHSTmp = RHS; llvm::Value *LHSTmp = LHS; bool wasCast = false; llvm::VectorType *rhsVTy = cast(RHS->getType()); if (rhsVTy->getElementType()->isFloatingPointTy()) { RHSTmp = Builder.CreateBitCast(RHS, tmp2->getType()); LHSTmp = Builder.CreateBitCast(LHS, tmp->getType()); wasCast = true; } llvm::Value *tmp3 = Builder.CreateAnd(RHSTmp, tmp2); llvm::Value *tmp4 = Builder.CreateAnd(LHSTmp, tmp); llvm::Value *tmp5 = Builder.CreateOr(tmp3, tmp4, "cond"); if (wasCast) tmp5 = Builder.CreateBitCast(tmp5, RHS->getType()); return tmp5; } if (condExpr->getType()->isVectorType()) { CGF.incrementProfileCounter(E); llvm::Value *CondV = CGF.EmitScalarExpr(condExpr); llvm::Value *LHS = Visit(lhsExpr); llvm::Value *RHS = Visit(rhsExpr); llvm::Type *CondType = ConvertType(condExpr->getType()); auto *VecTy = cast(CondType); llvm::Value *ZeroVec = llvm::Constant::getNullValue(VecTy); CondV = Builder.CreateICmpNE(CondV, ZeroVec, "vector_cond"); return Builder.CreateSelect(CondV, LHS, RHS, "vector_select"); } // If this is a really simple expression (like x ? 4 : 5), emit this as a // select instead of as control flow. We can only do this if it is cheap and // safe to evaluate the LHS and RHS unconditionally. if (isCheapEnoughToEvaluateUnconditionally(lhsExpr, CGF) && isCheapEnoughToEvaluateUnconditionally(rhsExpr, CGF)) { llvm::Value *CondV = CGF.EvaluateExprAsBool(condExpr); llvm::Value *StepV = Builder.CreateZExtOrBitCast(CondV, CGF.Int64Ty); CGF.incrementProfileCounter(E, StepV); llvm::Value *LHS = Visit(lhsExpr); llvm::Value *RHS = Visit(rhsExpr); if (!LHS) { // If the conditional has void type, make sure we return a null Value*. assert(!RHS && "LHS and RHS types must match"); return nullptr; } return Builder.CreateSelect(CondV, LHS, RHS, "cond"); } llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); CodeGenFunction::ConditionalEvaluation eval(CGF); CGF.EmitBranchOnBoolExpr(condExpr, LHSBlock, RHSBlock, CGF.getProfileCount(lhsExpr)); CGF.EmitBlock(LHSBlock); CGF.incrementProfileCounter(E); eval.begin(CGF); Value *LHS = Visit(lhsExpr); eval.end(CGF); LHSBlock = Builder.GetInsertBlock(); Builder.CreateBr(ContBlock); CGF.EmitBlock(RHSBlock); eval.begin(CGF); Value *RHS = Visit(rhsExpr); eval.end(CGF); RHSBlock = Builder.GetInsertBlock(); CGF.EmitBlock(ContBlock); // If the LHS or RHS is a throw expression, it will be legitimately null. if (!LHS) return RHS; if (!RHS) return LHS; // Create a PHI node for the real part. llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), 2, "cond"); PN->addIncoming(LHS, LHSBlock); PN->addIncoming(RHS, RHSBlock); return PN; } Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) { return Visit(E->getChosenSubExpr()); } Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { QualType Ty = VE->getType(); if (Ty->isVariablyModifiedType()) CGF.EmitVariablyModifiedType(Ty); Address ArgValue = Address::invalid(); Address ArgPtr = CGF.EmitVAArg(VE, ArgValue); llvm::Type *ArgTy = ConvertType(VE->getType()); // If EmitVAArg fails, emit an error. if (!ArgPtr.isValid()) { CGF.ErrorUnsupported(VE, "va_arg expression"); return llvm::UndefValue::get(ArgTy); } // FIXME Volatility. llvm::Value *Val = Builder.CreateLoad(ArgPtr); // If EmitVAArg promoted the type, we must truncate it. if (ArgTy != Val->getType()) { if (ArgTy->isPointerTy() && !Val->getType()->isPointerTy()) Val = Builder.CreateIntToPtr(Val, ArgTy); else Val = Builder.CreateTrunc(Val, ArgTy); } return Val; } Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *block) { return CGF.EmitBlockLiteral(block); } // Convert a vec3 to vec4, or vice versa. static Value *ConvertVec3AndVec4(CGBuilderTy &Builder, CodeGenFunction &CGF, Value *Src, unsigned NumElementsDst) { static constexpr int Mask[] = {0, 1, 2, -1}; return Builder.CreateShuffleVector(Src, llvm::makeArrayRef(Mask, NumElementsDst)); } // Create cast instructions for converting LLVM value \p Src to LLVM type \p // DstTy. \p Src has the same size as \p DstTy. Both are single value types // but could be scalar or vectors of different lengths, and either can be // pointer. // There are 4 cases: // 1. non-pointer -> non-pointer : needs 1 bitcast // 2. pointer -> pointer : needs 1 bitcast or addrspacecast // 3. pointer -> non-pointer // a) pointer -> intptr_t : needs 1 ptrtoint // b) pointer -> non-intptr_t : needs 1 ptrtoint then 1 bitcast // 4. non-pointer -> pointer // a) intptr_t -> pointer : needs 1 inttoptr // b) non-intptr_t -> pointer : needs 1 bitcast then 1 inttoptr // Note: for cases 3b and 4b two casts are required since LLVM casts do not // allow casting directly between pointer types and non-integer non-pointer // types. static Value *createCastsForTypeOfSameSize(CGBuilderTy &Builder, const llvm::DataLayout &DL, Value *Src, llvm::Type *DstTy, StringRef Name = "") { auto SrcTy = Src->getType(); // Case 1. if (!SrcTy->isPointerTy() && !DstTy->isPointerTy()) return Builder.CreateBitCast(Src, DstTy, Name); // Case 2. if (SrcTy->isPointerTy() && DstTy->isPointerTy()) return Builder.CreatePointerBitCastOrAddrSpaceCast(Src, DstTy, Name); // Case 3. if (SrcTy->isPointerTy() && !DstTy->isPointerTy()) { // Case 3b. if (!DstTy->isIntegerTy()) Src = Builder.CreatePtrToInt(Src, DL.getIntPtrType(SrcTy)); // Cases 3a and 3b. return Builder.CreateBitOrPointerCast(Src, DstTy, Name); } // Case 4b. if (!SrcTy->isIntegerTy()) Src = Builder.CreateBitCast(Src, DL.getIntPtrType(DstTy)); // Cases 4a and 4b. return Builder.CreateIntToPtr(Src, DstTy, Name); } Value *ScalarExprEmitter::VisitAsTypeExpr(AsTypeExpr *E) { Value *Src = CGF.EmitScalarExpr(E->getSrcExpr()); llvm::Type *DstTy = ConvertType(E->getType()); llvm::Type *SrcTy = Src->getType(); unsigned NumElementsSrc = isa(SrcTy) ? cast(SrcTy)->getNumElements() : 0; unsigned NumElementsDst = isa(DstTy) ? cast(DstTy)->getNumElements() : 0; // Going from vec3 to non-vec3 is a special case and requires a shuffle // vector to get a vec4, then a bitcast if the target type is different. if (NumElementsSrc == 3 && NumElementsDst != 3) { Src = ConvertVec3AndVec4(Builder, CGF, Src, 4); if (!CGF.CGM.getCodeGenOpts().PreserveVec3Type) { Src = createCastsForTypeOfSameSize(Builder, CGF.CGM.getDataLayout(), Src, DstTy); } Src->setName("astype"); return Src; } // Going from non-vec3 to vec3 is a special case and requires a bitcast // to vec4 if the original type is not vec4, then a shuffle vector to // get a vec3. if (NumElementsSrc != 3 && NumElementsDst == 3) { if (!CGF.CGM.getCodeGenOpts().PreserveVec3Type) { auto *Vec4Ty = llvm::FixedVectorType::get( cast(DstTy)->getElementType(), 4); Src = createCastsForTypeOfSameSize(Builder, CGF.CGM.getDataLayout(), Src, Vec4Ty); } Src = ConvertVec3AndVec4(Builder, CGF, Src, 3); Src->setName("astype"); return Src; } return createCastsForTypeOfSameSize(Builder, CGF.CGM.getDataLayout(), Src, DstTy, "astype"); } Value *ScalarExprEmitter::VisitAtomicExpr(AtomicExpr *E) { return CGF.EmitAtomicExpr(E).getScalarVal(); } //===----------------------------------------------------------------------===// // Entry Point into this File //===----------------------------------------------------------------------===// /// Emit the computation of the specified expression of scalar type, ignoring /// the result. Value *CodeGenFunction::EmitScalarExpr(const Expr *E, bool IgnoreResultAssign) { assert(E && hasScalarEvaluationKind(E->getType()) && "Invalid scalar expression to emit"); return ScalarExprEmitter(*this, IgnoreResultAssign) .Visit(const_cast(E)); } /// Emit a conversion from the specified type to the specified destination type, /// both of which are LLVM scalar types. Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy, SourceLocation Loc) { assert(hasScalarEvaluationKind(SrcTy) && hasScalarEvaluationKind(DstTy) && "Invalid scalar expression to emit"); return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy, Loc); } /// Emit a conversion from the specified complex type to the specified /// destination type, where the destination type is an LLVM scalar type. Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src, QualType SrcTy, QualType DstTy, SourceLocation Loc) { assert(SrcTy->isAnyComplexType() && hasScalarEvaluationKind(DstTy) && "Invalid complex -> scalar conversion"); return ScalarExprEmitter(*this) .EmitComplexToScalarConversion(Src, SrcTy, DstTy, Loc); } llvm::Value *CodeGenFunction:: EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV, bool isInc, bool isPre) { return ScalarExprEmitter(*this).EmitScalarPrePostIncDec(E, LV, isInc, isPre); } LValue CodeGenFunction::EmitObjCIsaExpr(const ObjCIsaExpr *E) { // object->isa or (*object).isa // Generate code as for: *(Class*)object Expr *BaseExpr = E->getBase(); Address Addr = Address::invalid(); if (BaseExpr->isRValue()) { Addr = Address(EmitScalarExpr(BaseExpr), getPointerAlign()); } else { Addr = EmitLValue(BaseExpr).getAddress(*this); } // Cast the address to Class*. Addr = Builder.CreateElementBitCast(Addr, ConvertType(E->getType())); return MakeAddrLValue(Addr, E->getType()); } LValue CodeGenFunction::EmitCompoundAssignmentLValue( const CompoundAssignOperator *E) { ScalarExprEmitter Scalar(*this); Value *Result = nullptr; switch (E->getOpcode()) { #define COMPOUND_OP(Op) \ case BO_##Op##Assign: \ return Scalar.EmitCompoundAssignLValue(E, &ScalarExprEmitter::Emit##Op, \ Result) COMPOUND_OP(Mul); COMPOUND_OP(Div); COMPOUND_OP(Rem); COMPOUND_OP(Add); COMPOUND_OP(Sub); COMPOUND_OP(Shl); COMPOUND_OP(Shr); COMPOUND_OP(And); COMPOUND_OP(Xor); COMPOUND_OP(Or); #undef COMPOUND_OP case BO_PtrMemD: case BO_PtrMemI: case BO_Mul: case BO_Div: case BO_Rem: case BO_Add: case BO_Sub: case BO_Shl: case BO_Shr: case BO_LT: case BO_GT: case BO_LE: case BO_GE: case BO_EQ: case BO_NE: case BO_Cmp: case BO_And: case BO_Xor: case BO_Or: case BO_LAnd: case BO_LOr: case BO_Assign: case BO_Comma: llvm_unreachable("Not valid compound assignment operators"); } llvm_unreachable("Unhandled compound assignment operator"); } struct GEPOffsetAndOverflow { // The total (signed) byte offset for the GEP. llvm::Value *TotalOffset; // The offset overflow flag - true if the total offset overflows. llvm::Value *OffsetOverflows; }; /// Evaluate given GEPVal, which is either an inbounds GEP, or a constant, /// and compute the total offset it applies from it's base pointer BasePtr. /// Returns offset in bytes and a boolean flag whether an overflow happened /// during evaluation. static GEPOffsetAndOverflow EmitGEPOffsetInBytes(Value *BasePtr, Value *GEPVal, llvm::LLVMContext &VMContext, CodeGenModule &CGM, CGBuilderTy &Builder) { const auto &DL = CGM.getDataLayout(); // The total (signed) byte offset for the GEP. llvm::Value *TotalOffset = nullptr; // Was the GEP already reduced to a constant? if (isa(GEPVal)) { // Compute the offset by casting both pointers to integers and subtracting: // GEPVal = BasePtr + ptr(Offset) <--> Offset = int(GEPVal) - int(BasePtr) Value *BasePtr_int = Builder.CreatePtrToInt(BasePtr, DL.getIntPtrType(BasePtr->getType())); Value *GEPVal_int = Builder.CreatePtrToInt(GEPVal, DL.getIntPtrType(GEPVal->getType())); TotalOffset = Builder.CreateSub(GEPVal_int, BasePtr_int); return {TotalOffset, /*OffsetOverflows=*/Builder.getFalse()}; } auto *GEP = cast(GEPVal); assert(GEP->getPointerOperand() == BasePtr && "BasePtr must be the the base of the GEP."); assert(GEP->isInBounds() && "Expected inbounds GEP"); auto *IntPtrTy = DL.getIntPtrType(GEP->getPointerOperandType()); // Grab references to the signed add/mul overflow intrinsics for intptr_t. auto *Zero = llvm::ConstantInt::getNullValue(IntPtrTy); auto *SAddIntrinsic = CGM.getIntrinsic(llvm::Intrinsic::sadd_with_overflow, IntPtrTy); auto *SMulIntrinsic = CGM.getIntrinsic(llvm::Intrinsic::smul_with_overflow, IntPtrTy); // The offset overflow flag - true if the total offset overflows. llvm::Value *OffsetOverflows = Builder.getFalse(); /// Return the result of the given binary operation. auto eval = [&](BinaryOperator::Opcode Opcode, llvm::Value *LHS, llvm::Value *RHS) -> llvm::Value * { assert((Opcode == BO_Add || Opcode == BO_Mul) && "Can't eval binop"); // If the operands are constants, return a constant result. if (auto *LHSCI = dyn_cast(LHS)) { if (auto *RHSCI = dyn_cast(RHS)) { llvm::APInt N; bool HasOverflow = mayHaveIntegerOverflow(LHSCI, RHSCI, Opcode, /*Signed=*/true, N); if (HasOverflow) OffsetOverflows = Builder.getTrue(); return llvm::ConstantInt::get(VMContext, N); } } // Otherwise, compute the result with checked arithmetic. auto *ResultAndOverflow = Builder.CreateCall( (Opcode == BO_Add) ? SAddIntrinsic : SMulIntrinsic, {LHS, RHS}); OffsetOverflows = Builder.CreateOr( Builder.CreateExtractValue(ResultAndOverflow, 1), OffsetOverflows); return Builder.CreateExtractValue(ResultAndOverflow, 0); }; // Determine the total byte offset by looking at each GEP operand. for (auto GTI = llvm::gep_type_begin(GEP), GTE = llvm::gep_type_end(GEP); GTI != GTE; ++GTI) { llvm::Value *LocalOffset; auto *Index = GTI.getOperand(); // Compute the local offset contributed by this indexing step: if (auto *STy = GTI.getStructTypeOrNull()) { // For struct indexing, the local offset is the byte position of the // specified field. unsigned FieldNo = cast(Index)->getZExtValue(); LocalOffset = llvm::ConstantInt::get( IntPtrTy, DL.getStructLayout(STy)->getElementOffset(FieldNo)); } else { // Otherwise this is array-like indexing. The local offset is the index // multiplied by the element size. auto *ElementSize = llvm::ConstantInt::get( IntPtrTy, DL.getTypeAllocSize(GTI.getIndexedType())); auto *IndexS = Builder.CreateIntCast(Index, IntPtrTy, /*isSigned=*/true); LocalOffset = eval(BO_Mul, ElementSize, IndexS); } // If this is the first offset, set it as the total offset. Otherwise, add // the local offset into the running total. if (!TotalOffset || TotalOffset == Zero) TotalOffset = LocalOffset; else TotalOffset = eval(BO_Add, TotalOffset, LocalOffset); } return {TotalOffset, OffsetOverflows}; } Value * CodeGenFunction::EmitCheckedInBoundsGEP(Value *Ptr, ArrayRef IdxList, bool SignedIndices, bool IsSubtraction, SourceLocation Loc, const Twine &Name) { Value *GEPVal = Builder.CreateInBoundsGEP(Ptr, IdxList, Name); // If the pointer overflow sanitizer isn't enabled, do nothing. if (!SanOpts.has(SanitizerKind::PointerOverflow)) return GEPVal; llvm::Type *PtrTy = Ptr->getType(); // Perform nullptr-and-offset check unless the nullptr is defined. bool PerformNullCheck = !NullPointerIsDefined( Builder.GetInsertBlock()->getParent(), PtrTy->getPointerAddressSpace()); // Check for overflows unless the GEP got constant-folded, // and only in the default address space bool PerformOverflowCheck = !isa(GEPVal) && PtrTy->getPointerAddressSpace() == 0; if (!(PerformNullCheck || PerformOverflowCheck)) return GEPVal; const auto &DL = CGM.getDataLayout(); SanitizerScope SanScope(this); llvm::Type *IntPtrTy = DL.getIntPtrType(PtrTy); GEPOffsetAndOverflow EvaluatedGEP = EmitGEPOffsetInBytes(Ptr, GEPVal, getLLVMContext(), CGM, Builder); assert((!isa(EvaluatedGEP.TotalOffset) || EvaluatedGEP.OffsetOverflows == Builder.getFalse()) && "If the offset got constant-folded, we don't expect that there was an " "overflow."); auto *Zero = llvm::ConstantInt::getNullValue(IntPtrTy); // Common case: if the total offset is zero, and we are using C++ semantics, // where nullptr+0 is defined, don't emit a check. if (EvaluatedGEP.TotalOffset == Zero && CGM.getLangOpts().CPlusPlus) return GEPVal; // Now that we've computed the total offset, add it to the base pointer (with // wrapping semantics). auto *IntPtr = Builder.CreatePtrToInt(Ptr, IntPtrTy); auto *ComputedGEP = Builder.CreateAdd(IntPtr, EvaluatedGEP.TotalOffset); llvm::SmallVector, 2> Checks; if (PerformNullCheck) { // In C++, if the base pointer evaluates to a null pointer value, // the only valid pointer this inbounds GEP can produce is also // a null pointer, so the offset must also evaluate to zero. // Likewise, if we have non-zero base pointer, we can not get null pointer // as a result, so the offset can not be -intptr_t(BasePtr). // In other words, both pointers are either null, or both are non-null, // or the behaviour is undefined. // // C, however, is more strict in this regard, and gives more // optimization opportunities: in C, additionally, nullptr+0 is undefined. // So both the input to the 'gep inbounds' AND the output must not be null. auto *BaseIsNotNullptr = Builder.CreateIsNotNull(Ptr); auto *ResultIsNotNullptr = Builder.CreateIsNotNull(ComputedGEP); auto *Valid = CGM.getLangOpts().CPlusPlus ? Builder.CreateICmpEQ(BaseIsNotNullptr, ResultIsNotNullptr) : Builder.CreateAnd(BaseIsNotNullptr, ResultIsNotNullptr); Checks.emplace_back(Valid, SanitizerKind::PointerOverflow); } if (PerformOverflowCheck) { // The GEP is valid if: // 1) The total offset doesn't overflow, and // 2) The sign of the difference between the computed address and the base // pointer matches the sign of the total offset. llvm::Value *ValidGEP; auto *NoOffsetOverflow = Builder.CreateNot(EvaluatedGEP.OffsetOverflows); if (SignedIndices) { // GEP is computed as `unsigned base + signed offset`, therefore: // * If offset was positive, then the computed pointer can not be // [unsigned] less than the base pointer, unless it overflowed. // * If offset was negative, then the computed pointer can not be // [unsigned] greater than the bas pointere, unless it overflowed. auto *PosOrZeroValid = Builder.CreateICmpUGE(ComputedGEP, IntPtr); auto *PosOrZeroOffset = Builder.CreateICmpSGE(EvaluatedGEP.TotalOffset, Zero); llvm::Value *NegValid = Builder.CreateICmpULT(ComputedGEP, IntPtr); ValidGEP = Builder.CreateSelect(PosOrZeroOffset, PosOrZeroValid, NegValid); } else if (!IsSubtraction) { // GEP is computed as `unsigned base + unsigned offset`, therefore the // computed pointer can not be [unsigned] less than base pointer, // unless there was an overflow. // Equivalent to `@llvm.uadd.with.overflow(%base, %offset)`. ValidGEP = Builder.CreateICmpUGE(ComputedGEP, IntPtr); } else { // GEP is computed as `unsigned base - unsigned offset`, therefore the // computed pointer can not be [unsigned] greater than base pointer, // unless there was an overflow. // Equivalent to `@llvm.usub.with.overflow(%base, sub(0, %offset))`. ValidGEP = Builder.CreateICmpULE(ComputedGEP, IntPtr); } ValidGEP = Builder.CreateAnd(ValidGEP, NoOffsetOverflow); Checks.emplace_back(ValidGEP, SanitizerKind::PointerOverflow); } assert(!Checks.empty() && "Should have produced some checks."); llvm::Constant *StaticArgs[] = {EmitCheckSourceLocation(Loc)}; // Pass the computed GEP to the runtime to avoid emitting poisoned arguments. llvm::Value *DynamicArgs[] = {IntPtr, ComputedGEP}; EmitCheck(Checks, SanitizerHandler::PointerOverflow, StaticArgs, DynamicArgs); return GEPVal; }