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llvm-project/clang/lib/CodeGen/CGExprScalar.cpp

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//===--- 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 "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "ConstantEmitter.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.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/FixedPoint.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/Optional.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Module.h"
#include <cstdarg>
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<llvm::ConstantInt>(LHS);
auto *RHSCI = dyn_cast<llvm::ConstantInt>(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<llvm::ConstantInt>(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<llvm::ConstantFP>(RHS))
return CFP->isZero();
return true;
}
/// Check if either operand is a fixed point type or integer type, with at
/// least one being a fixed point type. In any case, this
/// operation did not follow usual arithmetic conversion and both operands may
/// not be the same.
bool isFixedPointBinOp() const {
// We cannot simply check the result type since comparison operations return
// an int.
if (const auto *BinOp = dyn_cast<BinaryOperator>(E)) {
QualType LHSType = BinOp->getLHS()->getType();
QualType RHSType = BinOp->getRHS()->getType();
return LHSType->isFixedPointType() || RHSType->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<QualType> 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<UnaryOperator>(Op.E) || isa<BinaryOperator>(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<UnaryOperator>(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<BinaryOperator>(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;
}
/// Update the FastMathFlags of LLVM IR from the FPOptions in LangOptions.
static void updateFastMathFlags(llvm::FastMathFlags &FMF,
FPOptions FPFeatures) {
FMF.setAllowContract(FPFeatures.allowFPContractAcrossStatement());
}
/// Propagate fast-math flags from \p Op to the instruction in \p V.
static Value *propagateFMFlags(Value *V, const BinOpInfo &Op) {
if (auto *I = dyn_cast<llvm::Instruction>(V)) {
llvm::FastMathFlags FMF = I->getFastMathFlags();
updateFastMathFlags(FMF, Op.FPFeatures);
I->setFastMathFlags(FMF);
}
return V;
}
class ScalarExprEmitter
: public StmtVisitor<ScalarExprEmitter, Value*> {
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<std::pair<Value *, SanitizerMask>> 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<DeclRefExpr>(E)) {
const ValueDecl *VD = DRE->getDecl();
if (VD->getType()->isReferenceType()) {
if (const auto *TTy =
dyn_cast<TypedefType>(VD->getType().getNonReferenceType()))
AVAttr = TTy->getDecl()->getAttr<AlignValueAttr>();
} 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<ParmVarDecl>(VD) && !CGF.SanOpts.has(SanitizerKind::Alignment))
return;
AVAttr = VD->getAttr<AlignValueAttr>();
}
}
if (!AVAttr)
if (const auto *TTy =
dyn_cast<TypedefType>(E->getType()))
AVAttr = TTy->getDecl()->getAttr<AlignValueAttr>();
if (!AVAttr)
return;
Value *AlignmentValue = CGF.EmitScalarExpr(AVAttr->getAlignment());
llvm::ConstantInt *AlignmentCI = cast<llvm::ConstantInt>(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);
Value *EmitFixedPointConversion(Value *Src, FixedPointSemantics &SrcFixedSema,
FixedPointSemantics &DstFixedSema,
SourceLocation Loc,
bool DstIsInteger = false);
/// 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<llvm::PointerType>(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<llvm::ZExtInst>(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<ScalarExprEmitter, Value*>::Visit(E);
}
Value *VisitStmt(Stmt *S) {
S->dump(CGF.getContext().getSourceManager());
llvm_unreachable("Stmt can't have complex result type!");
}
Value *VisitExpr(Expr *S);
Value *VisitConstantExpr(ConstantExpr *E) {
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);
Optional<unsigned> Min = Version.getMinor(), SMin = Version.getSubminor();
llvm::Value *Args[] = {
llvm::ConstantInt::get(CGF.CGM.Int32Ty, Version.getMajor()),
llvm::ConstantInt::get(CGF.CGM.Int32Ty, Min ? *Min : 0),
llvm::ConstantInt::get(CGF.CGM.Int32Ty, SMin ? *SMin : 0),
};
return CGF.EmitBuiltinAvailable(Args);
}
Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E);
Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E);
Value *VisitConvertVectorExpr(ConvertVectorExpr *E);
Value *VisitMemberExpr(MemberExpr *E);
Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); }
Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
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<MemberPointerType>(E->getType())) // never sugared
return CGF.CGM.getMemberPointerConstant(E);
return EmitLValue(E->getSubExpr()).getPointer();
}
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 *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->isUnsignedIntegerType() &&
CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
!CanElideOverflowCheck(CGF.getContext(), Ops))
return EmitOverflowCheckedBinOp(Ops);
if (Ops.LHS->getType()->isFPOrFPVectorTy()) {
Value *V = Builder.CreateFMul(Ops.LHS, Ops.RHS, "mul");
return propagateFMFlags(V, 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);
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);
#define VISITCOMP(CODE, UI, SI, FP) \
Value *VisitBin##CODE(const BinaryOperator *E) { \
return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \
llvm::FCmpInst::FP); }
VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT)
VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT)
VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE)
VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE)
VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ)
VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE)
#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<MemberPointerType>(SrcType))
return CGF.CGM.getCXXABI().EmitMemberPointerIsNotNull(CGF, Src, MPT);
assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) &&
"Unknown scalar type to convert");
if (isa<llvm::IntegerType>(Src->getType()))
return EmitIntToBoolConversion(Src);
assert(isa<llvm::PointerType>(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<llvm::IntegerType>(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<ScalarExprEmitter::ImplicitConversionCheckKind,
std::pair<llvm::Value *, SanitizerMask>>
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<llvm::IntegerType>(SrcTy) && isa<llvm::IntegerType>(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<ScalarExprEmitter::ImplicitConversionCheckKind,
std::pair<llvm::Value *, SanitizerMask>>
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<ScalarExprEmitter::ImplicitConversionCheckKind,
std::pair<llvm::Value *, SanitizerMask>>
EmitIntegerSignChangeCheckHelper(Value *Src, QualType SrcType, Value *Dst,
QualType DstType, CGBuilderTy &Builder) {
llvm::Type *SrcTy = Src->getType();
llvm::Type *DstTy = Dst->getType();
assert(isa<llvm::IntegerType>(SrcTy) && isa<llvm::IntegerType>(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<ScalarExprEmitter::ImplicitConversionCheckKind,
std::pair<llvm::Value *, SanitizerMask>>
Check;
// Each of these checks needs to return 'false' when an issue was detected.
ImplicitConversionCheckKind CheckKind;
llvm::SmallVector<std::pair<llvm::Value *, SanitizerMask>, 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())
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())
// 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<llvm::PointerType>(DstTy)) {
// The source value may be an integer, or a pointer.
if (isa<llvm::PointerType>(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<llvm::PointerType>(SrcTy)) {
// Must be an ptr to int cast.
assert(isa<llvm::IntegerType>(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<ExtVectorType>()->getElementType().getTypePtr() ==
SrcType.getTypePtr() &&
"Splatted expr doesn't match with vector element type?");
// Splat the element across to all elements
unsigned NumElements = DstTy->getVectorNumElements();
return Builder.CreateVectorSplat(NumElements, Src, "splat");
}
if (isa<llvm::VectorType>(SrcTy) || isa<llvm::VectorType>(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 = SrcTy->getVectorElementType();
llvm::Type *DstElementTy = DstTy->getVectorElementType();
(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<llvm::IntegerType>(SrcTy)) {
bool InputSigned = SrcType->isSignedIntegerOrEnumerationType();
if (SrcType->isBooleanType() && Opts.TreatBooleanAsSigned) {
InputSigned = true;
}
if (isa<llvm::IntegerType>(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<llvm::IntegerType>(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) {
FixedPointSemantics SrcFPSema =
CGF.getContext().getFixedPointSemantics(SrcTy);
FixedPointSemantics DstFPSema =
CGF.getContext().getFixedPointSemantics(DstTy);
return EmitFixedPointConversion(Src, SrcFPSema, DstFPSema, Loc,
DstTy->isIntegerType());
}
Value *ScalarExprEmitter::EmitFixedPointConversion(
Value *Src, FixedPointSemantics &SrcFPSema, FixedPointSemantics &DstFPSema,
SourceLocation Loc, bool DstIsInteger) {
using llvm::APInt;
using llvm::ConstantInt;
using llvm::Value;
unsigned SrcWidth = SrcFPSema.getWidth();
unsigned DstWidth = DstFPSema.getWidth();
unsigned SrcScale = SrcFPSema.getScale();
unsigned DstScale = DstFPSema.getScale();
bool SrcIsSigned = SrcFPSema.isSigned();
bool DstIsSigned = DstFPSema.isSigned();
llvm::Type *DstIntTy = Builder.getIntNTy(DstWidth);
Value *Result = Src;
unsigned ResultWidth = SrcWidth;
// Downscale.
if (DstScale < SrcScale) {
// When converting to integers, we round towards zero. For negative numbers,
// right shifting rounds towards negative infinity. In this case, we can
// just round up before shifting.
if (DstIsInteger && SrcIsSigned) {
Value *Zero = llvm::Constant::getNullValue(Result->getType());
Value *IsNegative = Builder.CreateICmpSLT(Result, Zero);
Value *LowBits = ConstantInt::get(
CGF.getLLVMContext(), APInt::getLowBitsSet(ResultWidth, SrcScale));
Value *Rounded = Builder.CreateAdd(Result, LowBits);
Result = Builder.CreateSelect(IsNegative, Rounded, Result);
}
Result = SrcIsSigned
? Builder.CreateAShr(Result, SrcScale - DstScale, "downscale")
: Builder.CreateLShr(Result, SrcScale - DstScale, "downscale");
}
if (!DstFPSema.isSaturated()) {
// Resize.
Result = Builder.CreateIntCast(Result, DstIntTy, SrcIsSigned, "resize");
// Upscale.
if (DstScale > SrcScale)
Result = Builder.CreateShl(Result, DstScale - SrcScale, "upscale");
} else {
// Adjust the number of fractional bits.
if (DstScale > SrcScale) {
// Compare to DstWidth to prevent resizing twice.
ResultWidth = std::max(SrcWidth + DstScale - SrcScale, DstWidth);
llvm::Type *UpscaledTy = Builder.getIntNTy(ResultWidth);
Result = Builder.CreateIntCast(Result, UpscaledTy, SrcIsSigned, "resize");
Result = Builder.CreateShl(Result, DstScale - SrcScale, "upscale");
}
// Handle saturation.
bool LessIntBits = DstFPSema.getIntegralBits() < SrcFPSema.getIntegralBits();
if (LessIntBits) {
Value *Max = ConstantInt::get(
CGF.getLLVMContext(),
APFixedPoint::getMax(DstFPSema).getValue().extOrTrunc(ResultWidth));
Value *TooHigh = SrcIsSigned ? Builder.CreateICmpSGT(Result, Max)
: Builder.CreateICmpUGT(Result, Max);
Result = Builder.CreateSelect(TooHigh, Max, Result, "satmax");
}
// Cannot overflow min to dest type if src is unsigned since all fixed
// point types can cover the unsigned min of 0.
if (SrcIsSigned && (LessIntBits || !DstIsSigned)) {
Value *Min = ConstantInt::get(
CGF.getLLVMContext(),
APFixedPoint::getMin(DstFPSema).getValue().extOrTrunc(ResultWidth));
Value *TooLow = Builder.CreateICmpSLT(Result, Min);
Result = Builder.CreateSelect(TooLow, Min, Result, "satmin");
}
// Resize the integer part to get the final destination size.
if (ResultWidth != DstWidth)
Result = Builder.CreateIntCast(Result, DstIntTy, SrcIsSigned, "resize");
}
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<ComplexType>()->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<std::pair<Value *, SanitizerMask>> Checks, const BinOpInfo &Info) {
assert(CGF.IsSanitizerScope);
SanitizerHandler Check;
SmallVector<llvm::Constant *, 4> StaticData;
SmallVector<llvm::Value *, 2> 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<UnaryOperator>(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<BinaryOperator>(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;
llvm::VectorType *LTy = cast<llvm::VectorType>(LHS->getType());
unsigned LHSElts = LTy->getNumElements();
Mask = RHS;
llvm::VectorType *MTy = cast<llvm::VectorType>(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
llvm::VectorType *RTy = llvm::VectorType::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<llvm::Constant*, 32> 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(llvm::UndefValue::get(CGF.Int32Ty));
else
indices.push_back(Builder.getInt32(Idx.getZExtValue()));
}
Value *SV = llvm::ConstantVector::get(indices);
return Builder.CreateShuffleVector(V1, V2, SV, "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<VectorType>()->getElementType(),
DstEltType = DstType->castAs<VectorType>()->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 = SrcTy->getVectorElementType(),
*DstEltTy = DstTy->getVectorElementType();
if (DstEltType->isBooleanType()) {
assert((SrcEltTy->isFloatingPointTy() ||
isa<llvm::IntegerType>(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<llvm::IntegerType>(SrcEltTy)) {
bool InputSigned = SrcEltType->isSignedIntegerOrEnumerationType();
if (isa<llvm::IntegerType>(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<llvm::IntegerType>(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");
}
static llvm::Constant *getMaskElt(llvm::ShuffleVectorInst *SVI, unsigned Idx,
unsigned Off, llvm::Type *I32Ty) {
int MV = SVI->getMaskValue(Idx);
if (MV == -1)
return llvm::UndefValue::get(I32Ty);
return llvm::ConstantInt::get(I32Ty, Off+MV);
}
static llvm::Constant *getAsInt32(llvm::ConstantInt *C, llvm::Type *I32Ty) {
if (C->getBitWidth() != 32) {
assert(llvm::ConstantInt::isValueValidForType(I32Ty,
C->getZExtValue()) &&
"Index operand too large for shufflevector mask!");
return llvm::ConstantInt::get(I32Ty, C->getZExtValue());
}
return C;
}
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<llvm::VectorType>(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 = 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<llvm::Constant*, 16> Args;
llvm::VectorType *VVT = dyn_cast<llvm::VectorType>(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<ExtVectorElementExpr>(IE)) {
llvm::ExtractElementInst *EI = cast<llvm::ExtractElementInst>(Init);
if (EI->getVectorOperandType()->getNumElements() == ResElts) {
llvm::ConstantInt *C = cast<llvm::ConstantInt>(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, llvm::UndefValue::get(CGF.Int32Ty));
LHS = EI->getVectorOperand();
RHS = V;
VIsUndefShuffle = true;
} else if (VIsUndefShuffle) {
// insert into undefshuffle && size match -> shuffle (v, src)
llvm::ShuffleVectorInst *SVV = cast<llvm::ShuffleVectorInst>(V);
for (unsigned j = 0; j != CurIdx; ++j)
Args.push_back(getMaskElt(SVV, j, 0, CGF.Int32Ty));
Args.push_back(Builder.getInt32(ResElts + C->getZExtValue()));
Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
LHS = cast<llvm::ShuffleVectorInst>(V)->getOperand(0);
RHS = EI->getVectorOperand();
VIsUndefShuffle = false;
}
if (!Args.empty()) {
llvm::Constant *Mask = llvm::ConstantVector::get(Args);
V = Builder.CreateShuffleVector(LHS, RHS, Mask);
++CurIdx;
continue;
}
}
}
V = Builder.CreateInsertElement(V, Init, Builder.getInt32(CurIdx),
"vecinit");
VIsUndefShuffle = false;
++CurIdx;
continue;
}
unsigned InitElts = 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<ExtVectorElementExpr>(IE)) {
llvm::ShuffleVectorInst *SVI = cast<llvm::ShuffleVectorInst>(Init);
Value *SVOp = SVI->getOperand(0);
llvm::VectorType *OpTy = cast<llvm::VectorType>(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<llvm::ShuffleVectorInst>(V), j, 0,
CGF.Int32Ty));
} else {
Args.push_back(Builder.getInt32(j));
}
}
for (unsigned j = 0, je = InitElts; j != je; ++j)
Args.push_back(getMaskElt(SVI, j, Offset, CGF.Int32Ty));
Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
if (VIsUndefShuffle)
V = cast<llvm::ShuffleVectorInst>(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(Builder.getInt32(j));
Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
llvm::Constant *Mask = llvm::ConstantVector::get(Args);
Init = Builder.CreateShuffleVector(Init, llvm::UndefValue::get(VVT),
Mask, "vext");
Args.clear();
for (unsigned j = 0; j != CurIdx; ++j)
Args.push_back(Builder.getInt32(j));
for (unsigned j = 0; j != InitElts; ++j)
Args.push_back(Builder.getInt32(j+Offset));
Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
}
// 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);
llvm::Constant *Mask = llvm::ConstantVector::get(Args);
V = Builder.CreateShuffleVector(V, Init, Mask, "vecinit");
VIsUndefShuffle = isa<llvm::UndefValue>(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<CXXThisExpr>(E->IgnoreParens())) {
// We always assume that 'this' is never null.
return false;
}
if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(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();
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.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<Expr*>(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<PointerType>())
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 cast.
if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(Src))
if (CI->getMetadata("heapallocsite") && isa<ExplicitCastExpr>(CE))
CGF.getDebugInfo()->
addHeapAllocSiteMetadata(CI, CE->getType(), 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<llvm::PointerType>(
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<Expr*>(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<CXXDynamicCastExpr>(CE);
return CGF.EmitDynamicCast(V, DCE);
}
case CK_ArrayToPointerDecay:
return CGF.EmitArrayToPointerDecay(E).getPointer();
case CK_FunctionToPointerDecay:
return EmitLValue(E).getPointer();
case CK_NullToPointer:
if (MustVisitNullValue(E))
CGF.EmitIgnoredExpr(E);
return CGF.CGM.getNullPointer(cast<llvm::PointerType>(ConvertType(DestTy)),
DestTy);
case CK_NullToMemberPointer: {
if (MustVisitNullValue(E))
CGF.EmitIgnoredExpr(E);
const MemberPointerType *MPT = CE->getType()->getAs<MemberPointerType>();
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<Expr*>(E));
case CK_IntegralToPointer: {
Value *Src = Visit(const_cast<Expr*>(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<Expr*>(E));
// Splat the element across to all elements
unsigned NumElements = DstTy->getVectorNumElements();
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<ImplicitCastExpr>(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:
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:
return EmitFloatToBoolConversion(Visit(E));
case CK_MemberPointerToBoolean: {
llvm::Value *MemPtr = Visit(E);
const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>();
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) {
CGF.enterFullExpression(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) {
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;
// FIXME: once UnaryOperator carries FPFeatures, copy it here.
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));
}
llvm_unreachable("Unknown SignedOverflowBehaviorTy");
}
llvm::Value *
ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
bool isInc, bool isPre) {
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<AtomicType>()) {
type = atomicTy->getValueType();
if (isInc && type->isBooleanType()) {
llvm::Value *True = CGF.EmitToMemory(Builder.getTrue(), type);
if (isPre) {
Builder.CreateStore(True, LV.getAddress(), 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(), 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(), 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));
} 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<PointerType>()) {
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;
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<float>(amount)));
else if (value->getType()->isDoubleTy())
amt = llvm::ConstantFP::get(VMContext,
llvm::APFloat(static_cast<double>(amount)));
else {
// Remaining types are Half, LongDouble or __float128. Convert from float.
llvm::APFloat F(static_cast<float>(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");
}
}
// Objective-C pointer types.
} else {
const ObjCObjectPointerType *OPT = type->castAs<ObjCObjectPointerType>();
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;
// FIXME: once UnaryOperator carries FPFeatures, copy it here.
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()->isExtVectorType()) {
Value *Oper = Visit(E->getSubExpr());
Value *Zero = llvm::Constant::getNullValue(Oper->getType());
Value *Result;
if (Oper->getType()->isFPOrFPVectorTy())
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<RecordType>()->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<RecordType>()->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<RecordType>();
CXXRecordDecl *BaseRD = cast<CXXRecordDecl>(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->getFPFeatures();
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->getFPFeatures();
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<AtomicType>()) {
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(), 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());
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);
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<std::pair<llvm::Value *, SanitizerMask>, 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<BinaryOperator>(Ops.E);
if (CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow) &&
Ops.Ty->hasSignedIntegerRepresentation() &&
!IsWidenedIntegerOp(CGF.getContext(), BO->getLHS()) &&
Ops.mayHaveIntegerOverflow()) {
llvm::IntegerType *Ty = cast<llvm::IntegerType>(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 = 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<llvm::VectorType>(ValTy) &&
cast<llvm::VectorType>(ValTy)->getElementType()->isFloatTy()))
CGF.SetFPAccuracy(Val, 2.5);
}
return Val;
}
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;
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;
break;
case BO_Sub:
case BO_SubAssign:
OpID = 2;
IID = isSigned ? llvm::Intrinsic::ssub_with_overflow :
llvm::Intrinsic::usub_with_overflow;
break;
case BO_Mul:
case BO_MulAssign:
OpID = 3;
IID = isSigned ? llvm::Intrinsic::smul_with_overflow :
llvm::Intrinsic::umul_with_overflow;
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));
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<llvm::IntegerType>(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<BinaryOperator>(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<llvm::IntegerType>(index->getType())->getBitWidth();
auto &DL = CGF.CGM.getDataLayout();
auto PtrTy = cast<llvm::PointerType>(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.getTypeSizeInBits(PtrTy)) {
// Zero-extend or sign-extend the pointer value according to
// whether the index is signed or not.
index = CGF.Builder.CreateIntCast(index, DL.getIntPtrType(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<PointerType>();
if (!pointerType) {
QualType objectType = pointerOperand->getType()
->castAs<ObjCObjectPointerType>()
->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::BinaryOperator *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.CreateFSub(
llvm::ConstantFP::getZeroValueForNegation(MulOp0->getType()), MulOp0,
"neg");
} else if (negAdd) {
Addend =
Builder.CreateFSub(
llvm::ConstantFP::getZeroValueForNegation(Addend->getType()), Addend,
"neg");
}
Value *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<llvm::BinaryOperator>(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<llvm::BinaryOperator>(op.RHS)) {
if (RHSBinOp->getOpcode() == llvm::Instruction::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->isUnsignedIntegerType() &&
CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
!CanElideOverflowCheck(CGF.getContext(), op))
return EmitOverflowCheckedBinOp(op);
if (op.LHS->getType()->isFPOrFPVectorTy()) {
// Try to form an fmuladd.
if (Value *FMulAdd = tryEmitFMulAdd(op, CGF, Builder))
return FMulAdd;
Value *V = Builder.CreateFAdd(op.LHS, op.RHS, "add");
return propagateFMFlags(V, op);
}
if (op.isFixedPointBinOp())
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;
const auto *BinOp = cast<BinaryOperator>(op.E);
// The result is a fixed point type and at least one of the operands is fixed
// point while the other is either fixed point or an int. This resulting type
// should be determined by Sema::handleFixedPointConversions().
QualType ResultTy = op.Ty;
QualType LHSTy = BinOp->getLHS()->getType();
QualType RHSTy = BinOp->getRHS()->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);
// Convert the operands to the full precision type.
Value *FullLHS = EmitFixedPointConversion(LHS, LHSFixedSema, CommonFixedSema,
BinOp->getExprLoc());
Value *FullRHS = EmitFixedPointConversion(RHS, RHSFixedSema, CommonFixedSema,
BinOp->getExprLoc());
// Perform the actual addition.
Value *Result;
switch (BinOp->getOpcode()) {
case BO_Add: {
if (ResultFixedSema.isSaturated()) {
llvm::Intrinsic::ID IID = ResultFixedSema.isSigned()
? llvm::Intrinsic::sadd_sat
: llvm::Intrinsic::uadd_sat;
Result = Builder.CreateBinaryIntrinsic(IID, FullLHS, FullRHS);
} else {
Result = Builder.CreateAdd(FullLHS, FullRHS);
}
break;
}
case BO_Sub: {
if (ResultFixedSema.isSaturated()) {
llvm::Intrinsic::ID IID = ResultFixedSema.isSigned()
? llvm::Intrinsic::ssub_sat
: llvm::Intrinsic::usub_sat;
Result = Builder.CreateBinaryIntrinsic(IID, FullLHS, FullRHS);
} else {
Result = Builder.CreateSub(FullLHS, FullRHS);
}
break;
}
case BO_LT:
return CommonFixedSema.isSigned() ? Builder.CreateICmpSLT(FullLHS, FullRHS)
: Builder.CreateICmpULT(FullLHS, FullRHS);
case BO_GT:
return CommonFixedSema.isSigned() ? Builder.CreateICmpSGT(FullLHS, FullRHS)
: Builder.CreateICmpUGT(FullLHS, FullRHS);
case BO_LE:
return CommonFixedSema.isSigned() ? Builder.CreateICmpSLE(FullLHS, FullRHS)
: Builder.CreateICmpULE(FullLHS, FullRHS);
case BO_GE:
return CommonFixedSema.isSigned() ? Builder.CreateICmpSGE(FullLHS, FullRHS)
: Builder.CreateICmpUGE(FullLHS, FullRHS);
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 Builder.CreateICmpEQ(FullLHS, FullRHS);
case BO_NE:
return Builder.CreateICmpNE(FullLHS, FullRHS);
case BO_Mul:
case BO_Div:
case BO_Shl:
case BO_Shr:
case BO_Cmp:
case BO_LAnd:
case BO_LOr:
case BO_MulAssign:
case BO_DivAssign:
case BO_AddAssign:
case BO_SubAssign:
case BO_ShlAssign:
case BO_ShrAssign:
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.");
}
// Convert to the result type.
return EmitFixedPointConversion(Result, CommonFixedSema, ResultFixedSema,
BinOp->getExprLoc());
}
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->isUnsignedIntegerType() &&
CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
!CanElideOverflowCheck(CGF.getContext(), op))
return EmitOverflowCheckedBinOp(op);
if (op.LHS->getType()->isFPOrFPVectorTy()) {
// Try to form an fmuladd.
if (Value *FMulAdd = tryEmitFMulAdd(op, CGF, Builder, true))
return FMulAdd;
Value *V = Builder.CreateFSub(op.LHS, op.RHS, "sub");
return propagateFMFlags(V, op);
}
if (op.isFixedPointBinOp())
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<BinaryOperator>(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<llvm::VectorType>(LHS->getType()))
Ty = cast<llvm::IntegerType>(VT->getElementType());
else
Ty = cast<llvm::IntegerType>(LHS->getType());
return llvm::ConstantInt::get(RHS->getType(), Ty->getBitWidth() - 1);
}
Value *ScalarExprEmitter::EmitShl(const BinOpInfo &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 SanitizeBase = CGF.SanOpts.has(SanitizerKind::ShiftBase) &&
Ops.Ty->hasSignedIntegerRepresentation() &&
!CGF.getLangOpts().isSignedOverflowDefined() &&
!CGF.getLangOpts().CPlusPlus2a;
bool SanitizeExponent = CGF.SanOpts.has(SanitizerKind::ShiftExponent);
// OpenCL 6.3j: shift values are effectively % word size of LHS.
if (CGF.getLangOpts().OpenCL)
RHS =
Builder.CreateAnd(RHS, GetWidthMinusOneValue(Ops.LHS, RHS), "shl.mask");
else if ((SanitizeBase || SanitizeExponent) &&
isa<llvm::IntegerType>(Ops.LHS->getType())) {
CodeGenFunction::SanitizerScope SanScope(&CGF);
SmallVector<std::pair<Value *, SanitizerMask>, 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 (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).
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, SanitizerKind::ShiftBase));
}
assert(!Checks.empty());
EmitBinOpCheck(Checks, Ops);
}
return Builder.CreateShl(Ops.LHS, RHS, "shl");
}
Value *ScalarExprEmitter::EmitShr(const BinOpInfo &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 =
Builder.CreateAnd(RHS, GetWidthMinusOneValue(Ops.LHS, RHS), "shr.mask");
else if (CGF.SanOpts.has(SanitizerKind::ShiftExponent) &&
isa<llvm::IntegerType>(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;
}
}
Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,
llvm::CmpInst::Predicate UICmpOpc,
llvm::CmpInst::Predicate SICmpOpc,
llvm::CmpInst::Predicate FCmpOpc) {
TestAndClearIgnoreResultAssign();
Value *Result;
QualType LHSTy = E->getLHS()->getType();
QualType RHSTy = E->getRHS()->getType();
if (const MemberPointerType *MPT = LHSTy->getAs<MemberPointerType>()) {
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<VectorType>()->getElementType();
const BuiltinType *BTy = ElTy->getAs<BuiltinType>();
BuiltinType::Kind ElementKind = BTy->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<llvm::IntegerType>(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.isFixedPointBinOp()) {
Result = EmitFixedPointBinOp(BOInfo);
} else if (LHS->getType()->isFPOrFPVectorTy()) {
Result = Builder.CreateFCmp(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<llvm::ConstantPointerNull>(LHS) &&
!isa<llvm::ConstantPointerNull>(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<ComplexType>()) {
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<ComplexType>()) {
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()) {
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(), 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()) {
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");
}
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());
// 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();
// 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()) {
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");
}
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());
// 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();
// 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()) {
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());
llvm::VectorType *vecTy = cast<llvm::VectorType>(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::VectorType::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<llvm::VectorType>(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 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) {
llvm::Value *UnV = llvm::UndefValue::get(Src->getType());
SmallVector<llvm::Constant*, 4> Args;
Args.push_back(Builder.getInt32(0));
Args.push_back(Builder.getInt32(1));
Args.push_back(Builder.getInt32(2));
if (NumElementsDst == 4)
Args.push_back(llvm::UndefValue::get(CGF.Int32Ty));
llvm::Constant *Mask = llvm::ConstantVector::get(Args);
return Builder.CreateShuffleVector(Src, UnV, Mask);
}
// 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<llvm::VectorType>(SrcTy) ?
cast<llvm::VectorType>(SrcTy)->getNumElements() : 0;
unsigned NumElementsDst = isa<llvm::VectorType>(DstTy) ?
cast<llvm::VectorType>(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::VectorType::get(DstTy->getVectorElementType(), 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<Expr *>(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();
}
// 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<llvm::Constant>(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<llvm::GEPOperator>(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<llvm::ConstantInt>(LHS)) {
if (auto *RHSCI = dyn_cast<llvm::ConstantInt>(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<llvm::ConstantInt>(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<Value *> 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<llvm::Constant>(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<llvm::Constant>(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<std::pair<llvm::Value *, SanitizerMask>, 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;
}
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