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gerrit-public.fairphone.software / platform / external / clang / c034974f103873bdccc91da99a30ab30295b5226 / . / lib / CodeGen / CGExprScalar.cpp
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//===--- CGExprScalar.cpp - Emit LLVM Code for Scalar Exprs ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Expr nodes with scalar LLVM types as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "CGObjCRuntime.h"
#include "CodeGenModule.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Intrinsics.h"
#include "llvm/Module.h"
#include "llvm/Support/CFG.h"
#include "llvm/Target/TargetData.h"
#include <cstdarg>
using namespace clang;
using namespace CodeGen;
using llvm::Value;
//===----------------------------------------------------------------------===//
// Scalar Expression Emitter
//===----------------------------------------------------------------------===//
struct BinOpInfo {
Value *LHS;
Value *RHS;
QualType Ty; // Computation Type.
const BinaryOperator *E;
};
namespace {
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;
}
const llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); }
LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); }
LValue EmitCheckedLValue(const Expr *E) { return CGF.EmitCheckedLValue(E); }
Value *EmitLoadOfLValue(LValue LV, QualType T) {
return CGF.EmitLoadOfLValue(LV, T).getScalarVal();
}
/// 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) {
return EmitLoadOfLValue(EmitCheckedLValue(E), E->getType());
}
/// EmitConversionToBool - Convert the specified expression value to a
/// boolean (i1) truth value. This is equivalent to "Val != 0".
Value *EmitConversionToBool(Value *Src, QualType DstTy);
/// EmitScalarConversion - Emit a conversion from the specified type to the
/// specified destination type, both of which are LLVM scalar types.
Value *EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy);
/// EmitComplexToScalarConversion - 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);
//===--------------------------------------------------------------------===//
// Visitor Methods
//===--------------------------------------------------------------------===//
Value *VisitStmt(Stmt *S) {
S->dump(CGF.getContext().getSourceManager());
assert(0 && "Stmt can't have complex result type!");
return 0;
}
Value *VisitExpr(Expr *S);
Value *VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr()); }
// Leaves.
Value *VisitIntegerLiteral(const IntegerLiteral *E) {
return llvm::ConstantInt::get(VMContext, 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 *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
}
Value *VisitCXXZeroInitValueExpr(const CXXZeroInitValueExpr *E) {
return llvm::Constant::getNullValue(ConvertType(E->getType()));
}
Value *VisitGNUNullExpr(const GNUNullExpr *E) {
return llvm::Constant::getNullValue(ConvertType(E->getType()));
}
Value *VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) {
return llvm::ConstantInt::get(ConvertType(E->getType()),
CGF.getContext().typesAreCompatible(
E->getArgType1(), E->getArgType2()));
}
Value *VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E);
Value *VisitAddrLabelExpr(const AddrLabelExpr *E) {
llvm::Value *V = CGF.GetAddrOfLabel(E->getLabel());
return Builder.CreateBitCast(V, ConvertType(E->getType()));
}
// l-values.
Value *VisitDeclRefExpr(DeclRefExpr *E) {
Expr::EvalResult Result;
if (E->Evaluate(Result, CGF.getContext()) && Result.Val.isInt()) {
assert(!Result.HasSideEffects && "Constant declref with side-effect?!");
return llvm::ConstantInt::get(VMContext, Result.Val.getInt());
}
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 *VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) {
return EmitLoadOfLValue(E);
}
Value *VisitObjCImplicitSetterGetterRefExpr(
ObjCImplicitSetterGetterRefExpr *E) {
return EmitLoadOfLValue(E);
}
Value *VisitObjCMessageExpr(ObjCMessageExpr *E) {
return CGF.EmitObjCMessageExpr(E).getScalarVal();
}
Value *VisitObjCIsaExpr(ObjCIsaExpr *E) {
LValue LV = CGF.EmitObjCIsaExpr(E);
Value *V = CGF.EmitLoadOfLValue(LV, E->getType()).getScalarVal();
return V;
}
Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E);
Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E);
Value *VisitMemberExpr(MemberExpr *E);
Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); }
Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
return EmitLoadOfLValue(E);
}
Value *VisitInitListExpr(InitListExpr *E);
Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
return llvm::Constant::getNullValue(ConvertType(E->getType()));
}
Value *VisitCastExpr(CastExpr *E) {
// Make sure to evaluate VLA bounds now so that we have them for later.
if (E->getType()->isVariablyModifiedType())
CGF.EmitVLASize(E->getType());
return EmitCastExpr(E);
}
Value *EmitCastExpr(CastExpr *E);
Value *VisitCallExpr(const CallExpr *E) {
if (E->getCallReturnType()->isReferenceType())
return EmitLoadOfLValue(E);
return CGF.EmitCallExpr(E).getScalarVal();
}
Value *VisitStmtExpr(const StmtExpr *E);
Value *VisitBlockDeclRefExpr(const BlockDeclRefExpr *E);
// Unary Operators.
Value *VisitPrePostIncDec(const UnaryOperator *E, bool isInc, bool isPre) {
LValue LV = EmitLValue(E->getSubExpr());
return CGF.EmitScalarPrePostIncDec(E, LV, isInc, isPre);
}
Value *VisitUnaryPostDec(const UnaryOperator *E) {
return VisitPrePostIncDec(E, false, false);
}
Value *VisitUnaryPostInc(const UnaryOperator *E) {
return VisitPrePostIncDec(E, true, false);
}
Value *VisitUnaryPreDec(const UnaryOperator *E) {
return VisitPrePostIncDec(E, false, true);
}
Value *VisitUnaryPreInc(const UnaryOperator *E) {
return VisitPrePostIncDec(E, true, true);
}
Value *VisitUnaryAddrOf(const UnaryOperator *E) {
return EmitLValue(E->getSubExpr()).getAddress();
}
Value *VisitUnaryDeref(const Expr *E) { 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());
}
Value *VisitUnaryOffsetOf(const UnaryOperator *E);
// C++
Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
return Visit(DAE->getExpr());
}
Value *VisitCXXThisExpr(CXXThisExpr *TE) {
return CGF.LoadCXXThis();
}
Value *VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E) {
return CGF.EmitCXXExprWithTemporaries(E).getScalarVal();
}
Value *VisitCXXNewExpr(const CXXNewExpr *E) {
return CGF.EmitCXXNewExpr(E);
}
Value *VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
CGF.EmitCXXDeleteExpr(E);
return 0;
}
Value *VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr *E) {
return llvm::ConstantInt::get(Builder.getInt1Ty(),
E->EvaluateTrait(CGF.getContext()));
}
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 0;
}
Value *VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
return llvm::Constant::getNullValue(ConvertType(E->getType()));
}
Value *VisitCXXThrowExpr(const CXXThrowExpr *E) {
CGF.EmitCXXThrowExpr(E);
return 0;
}
// Binary Operators.
Value *EmitMul(const BinOpInfo &Ops) {
if (CGF.getContext().getLangOptions().OverflowChecking
&& Ops.Ty->isSignedIntegerType())
return EmitOverflowCheckedBinOp(Ops);
if (Ops.LHS->getType()->isFPOrFPVectorTy())
return Builder.CreateFMul(Ops.LHS, Ops.RHS, "mul");
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);
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");
}
BinOpInfo EmitBinOps(const BinaryOperator *E);
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, unsigned UICmpOpc,
unsigned SICmpOpc, unsigned 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); }
// Other Operators.
Value *VisitBlockExpr(const BlockExpr *BE);
Value *VisitConditionalOperator(const ConditionalOperator *CO);
Value *VisitChooseExpr(ChooseExpr *CE);
Value *VisitVAArgExpr(VAArgExpr *VE);
Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) {
return CGF.EmitObjCStringLiteral(E);
}
};
} // 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()) {
// Compare against 0.0 for fp scalars.
llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType());
return Builder.CreateFCmpUNE(Src, Zero, "tobool");
}
if (SrcType->isMemberPointerType()) {
// Compare against -1.
llvm::Value *NegativeOne = llvm::Constant::getAllOnesValue(Src->getType());
return Builder.CreateICmpNE(Src, NegativeOne, "tobool");
}
assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) &&
"Unknown scalar type to convert");
// 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>(Src)) {
if (ZI->getOperand(0)->getType() ==
llvm::Type::getInt1Ty(CGF.getLLVMContext())) {
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;
}
}
// Compare against an integer or pointer null.
llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType());
return Builder.CreateICmpNE(Src, Zero, "tobool");
}
/// EmitScalarConversion - 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) {
SrcType = CGF.getContext().getCanonicalType(SrcType);
DstType = CGF.getContext().getCanonicalType(DstType);
if (SrcType == DstType) return Src;
if (DstType->isVoidType()) return 0;
llvm::LLVMContext &VMContext = CGF.getLLVMContext();
// Handle conversions to bool first, they are special: comparisons against 0.
if (DstType->isBooleanType())
return EmitConversionToBool(Src, SrcType);
const llvm::Type *DstTy = ConvertType(DstType);
// Ignore conversions like int -> uint.
if (Src->getType() == DstTy)
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 (isa<llvm::PointerType>(DstTy)) {
// The source value may be an integer, or a pointer.
if (isa<llvm::PointerType>(Src->getType()))
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.
const llvm::Type *MiddleTy =
llvm::IntegerType::get(VMContext, CGF.LLVMPointerWidth);
bool InputSigned = SrcType->isSignedIntegerType();
llvm::Value* IntResult =
Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
// Then, cast to pointer.
return Builder.CreateIntToPtr(IntResult, DstTy, "conv");
}
if (isa<llvm::PointerType>(Src->getType())) {
// 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()) {
// Cast the scalar to element type
QualType EltTy = DstType->getAs<ExtVectorType>()->getElementType();
llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy);
// Insert the element in element zero of an undef vector
llvm::Value *UnV = llvm::UndefValue::get(DstTy);
llvm::Value *Idx =
llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 0);
UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp");
// Splat the element across to all elements
llvm::SmallVector<llvm::Constant*, 16> Args;
unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements();
for (unsigned i = 0; i < NumElements; i++)
Args.push_back(llvm::ConstantInt::get(
llvm::Type::getInt32Ty(VMContext), 0));
llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements);
llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat");
return Yay;
}
// Allow bitcast from vector to integer/fp of the same size.
if (isa<llvm::VectorType>(Src->getType()) ||
isa<llvm::VectorType>(DstTy))
return Builder.CreateBitCast(Src, DstTy, "conv");
// Finally, we have the arithmetic types: real int/float.
if (isa<llvm::IntegerType>(Src->getType())) {
bool InputSigned = SrcType->isSignedIntegerType();
if (isa<llvm::IntegerType>(DstTy))
return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv");
else if (InputSigned)
return Builder.CreateSIToFP(Src, DstTy, "conv");
else
return Builder.CreateUIToFP(Src, DstTy, "conv");
}
assert(Src->getType()->isFloatingPointTy() && "Unknown real conversion");
if (isa<llvm::IntegerType>(DstTy)) {
if (DstType->isSignedIntegerType())
return Builder.CreateFPToSI(Src, DstTy, "conv");
else
return Builder.CreateFPToUI(Src, DstTy, "conv");
}
assert(DstTy->isFloatingPointTy() && "Unknown real conversion");
if (DstTy->getTypeID() < Src->getType()->getTypeID())
return Builder.CreateFPTrunc(Src, DstTy, "conv");
else
return Builder.CreateFPExt(Src, DstTy, "conv");
}
/// EmitComplexToScalarConversion - 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) {
// Get the source element type.
SrcTy = SrcTy->getAs<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);
Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy);
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);
}
//===----------------------------------------------------------------------===//
// Visitor Methods
//===----------------------------------------------------------------------===//
Value *ScalarExprEmitter::VisitExpr(Expr *E) {
CGF.ErrorUnsupported(E, "scalar expression");
if (E->getType()->isVoidType())
return 0;
return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
}
Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
llvm::SmallVector<llvm::Constant*, 32> indices;
for (unsigned i = 2; i < E->getNumSubExprs(); i++) {
indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i))));
}
Value* V1 = CGF.EmitScalarExpr(E->getExpr(0));
Value* V2 = CGF.EmitScalarExpr(E->getExpr(1));
Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size());
return Builder.CreateShuffleVector(V1, V2, SV, "shuffle");
}
Value *ScalarExprEmitter::VisitMemberExpr(MemberExpr *E) {
Expr::EvalResult Result;
if (E->Evaluate(Result, CGF.getContext()) && Result.Val.isInt()) {
if (E->isArrow())
CGF.EmitScalarExpr(E->getBase());
else
EmitLValue(E->getBase());
return llvm::ConstantInt::get(VMContext, Result.Val.getInt());
}
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());
bool IdxSigned = E->getIdx()->getType()->isSignedIntegerType();
Idx = Builder.CreateIntCast(Idx,
llvm::Type::getInt32Ty(CGF.getLLVMContext()),
IdxSigned,
"vecidxcast");
return Builder.CreateExtractElement(Base, Idx, "vecext");
}
static llvm::Constant *getMaskElt(llvm::ShuffleVectorInst *SVI, unsigned Idx,
unsigned Off, const llvm::Type *I32Ty) {
int MV = SVI->getMaskValue(Idx);
if (MV == -1)
return llvm::UndefValue::get(I32Ty);
return llvm::ConstantInt::get(I32Ty, Off+MV);
}
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");
const llvm::VectorType *VType =
dyn_cast<llvm::VectorType>(ConvertType(E->getType()));
// We have a scalar in braces. Just use the first element.
if (!VType)
return Visit(E->getInit(0));
unsigned ResElts = VType->getNumElements();
const llvm::Type *I32Ty = llvm::Type::getInt32Ty(CGF.getLLVMContext());
// 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);
llvm::SmallVector<llvm::Constant*, 16> Args;
const 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 = 0, *RHS = 0;
if (CurIdx == 0) {
// insert into undef -> shuffle (src, undef)
Args.push_back(C);
for (unsigned j = 1; j != ResElts; ++j)
Args.push_back(llvm::UndefValue::get(I32Ty));
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, I32Ty));
Args.push_back(llvm::ConstantInt::get(I32Ty,
ResElts + C->getZExtValue()));
for (unsigned j = CurIdx + 1; j != ResElts; ++j)
Args.push_back(llvm::UndefValue::get(I32Ty));
LHS = cast<llvm::ShuffleVectorInst>(V)->getOperand(0);
RHS = EI->getVectorOperand();
VIsUndefShuffle = false;
}
if (!Args.empty()) {
llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], ResElts);
V = Builder.CreateShuffleVector(LHS, RHS, Mask);
++CurIdx;
continue;
}
}
}
Value *Idx = llvm::ConstantInt::get(I32Ty, CurIdx);
V = Builder.CreateInsertElement(V, Init, Idx, "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);
const 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,
I32Ty));
} else {
Args.push_back(llvm::ConstantInt::get(I32Ty, j));
}
}
for (unsigned j = 0, je = InitElts; j != je; ++j)
Args.push_back(getMaskElt(SVI, j, Offset, I32Ty));
for (unsigned j = CurIdx + InitElts; j != ResElts; ++j)
Args.push_back(llvm::UndefValue::get(I32Ty));
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(llvm::ConstantInt::get(I32Ty, j));
for (unsigned j = InitElts; j != ResElts; ++j)
Args.push_back(llvm::UndefValue::get(I32Ty));
llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], ResElts);
Init = Builder.CreateShuffleVector(Init, llvm::UndefValue::get(VVT),
Mask, "vext");
Args.clear();
for (unsigned j = 0; j != CurIdx; ++j)
Args.push_back(llvm::ConstantInt::get(I32Ty, j));
for (unsigned j = 0; j != InitElts; ++j)
Args.push_back(llvm::ConstantInt::get(I32Ty, j+Offset));
for (unsigned j = CurIdx + InitElts; j != ResElts; ++j)
Args.push_back(llvm::UndefValue::get(I32Ty));
}
// 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[0], ResElts);
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.
const llvm::Type *EltTy = VType->getElementType();
// Emit remaining default initializers
for (/* Do not initialize i*/; CurIdx < ResElts; ++CurIdx) {
Value *Idx = llvm::ConstantInt::get(I32Ty, CurIdx);
llvm::Value *Init = llvm::Constant::getNullValue(EltTy);
V = Builder.CreateInsertElement(V, Init, Idx, "vecinit");
}
return V;
}
static bool ShouldNullCheckClassCastValue(const CastExpr *CE) {
const Expr *E = CE->getSubExpr();
if (CE->getCastKind() == CastExpr::CK_UncheckedDerivedToBase)
return false;
if (isa<CXXThisExpr>(E)) {
// We always assume that 'this' is never null.
return false;
}
if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(CE)) {
// And that lvalue casts are never null.
if (ICE->isLvalueCast())
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::EmitCastExpr(CastExpr *CE) {
Expr *E = CE->getSubExpr();
QualType DestTy = CE->getType();
CastExpr::CastKind Kind = CE->getCastKind();
if (!DestTy->isVoidType())
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 CastExpr::CK_Unknown:
// FIXME: All casts should have a known kind!
//assert(0 && "Unknown cast kind!");
break;
case CastExpr::CK_AnyPointerToObjCPointerCast:
case CastExpr::CK_AnyPointerToBlockPointerCast:
case CastExpr::CK_BitCast: {
Value *Src = Visit(const_cast<Expr*>(E));
return Builder.CreateBitCast(Src, ConvertType(DestTy));
}
case CastExpr::CK_NoOp:
case CastExpr::CK_UserDefinedConversion:
return Visit(const_cast<Expr*>(E));
case CastExpr::CK_BaseToDerived: {
const CXXRecordDecl *BaseClassDecl =
E->getType()->getCXXRecordDeclForPointerType();
const CXXRecordDecl *DerivedClassDecl =
DestTy->getCXXRecordDeclForPointerType();
Value *Src = Visit(const_cast<Expr*>(E));
bool NullCheckValue = ShouldNullCheckClassCastValue(CE);
return CGF.GetAddressOfDerivedClass(Src, BaseClassDecl, DerivedClassDecl,
NullCheckValue);
}
case CastExpr::CK_UncheckedDerivedToBase:
case CastExpr::CK_DerivedToBase: {
const RecordType *DerivedClassTy =
E->getType()->getAs<PointerType>()->getPointeeType()->getAs<RecordType>();
CXXRecordDecl *DerivedClassDecl =
cast<CXXRecordDecl>(DerivedClassTy->getDecl());
const RecordType *BaseClassTy =
DestTy->getAs<PointerType>()->getPointeeType()->getAs<RecordType>();
CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseClassTy->getDecl());
Value *Src = Visit(const_cast<Expr*>(E));
bool NullCheckValue = ShouldNullCheckClassCastValue(CE);
return CGF.GetAddressOfBaseClass(Src, DerivedClassDecl, BaseClassDecl,
NullCheckValue);
}
case CastExpr::CK_Dynamic: {
Value *V = Visit(const_cast<Expr*>(E));
const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(CE);
return CGF.EmitDynamicCast(V, DCE);
}
case CastExpr::CK_ToUnion:
assert(0 && "Should be unreachable!");
break;
case CastExpr::CK_ArrayToPointerDecay: {
assert(E->getType()->isArrayType() &&
"Array to pointer decay must have array source type!");
Value *V = EmitLValue(E).getAddress(); // Bitfields can't be arrays.
// Note that VLA pointers are always decayed, so we don't need to do
// anything here.
if (!E->getType()->isVariableArrayType()) {
assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer");
assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType())
->getElementType()) &&
"Expected pointer to array");
V = Builder.CreateStructGEP(V, 0, "arraydecay");
}
return V;
}
case CastExpr::CK_FunctionToPointerDecay:
return EmitLValue(E).getAddress();
case CastExpr::CK_NullToMemberPointer:
return CGF.CGM.EmitNullConstant(DestTy);
case CastExpr::CK_BaseToDerivedMemberPointer:
case CastExpr::CK_DerivedToBaseMemberPointer: {
Value *Src = Visit(E);
// See if we need to adjust the pointer.
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(E->getType()->getAs<MemberPointerType>()->
getClass()->getAs<RecordType>()->getDecl());
const CXXRecordDecl *DerivedDecl =
cast<CXXRecordDecl>(CE->getType()->getAs<MemberPointerType>()->
getClass()->getAs<RecordType>()->getDecl());
if (CE->getCastKind() == CastExpr::CK_DerivedToBaseMemberPointer)
std::swap(DerivedDecl, BaseDecl);
if (llvm::Constant *Adj =
CGF.CGM.GetNonVirtualBaseClassOffset(DerivedDecl, BaseDecl)) {
if (CE->getCastKind() == CastExpr::CK_DerivedToBaseMemberPointer)
Src = Builder.CreateSub(Src, Adj, "adj");
else
Src = Builder.CreateAdd(Src, Adj, "adj");
}
return Src;
}
case CastExpr::CK_ConstructorConversion:
assert(0 && "Should be unreachable!");
break;
case CastExpr::CK_IntegralToPointer: {
Value *Src = Visit(const_cast<Expr*>(E));
// First, convert to the correct width so that we control the kind of
// extension.
const llvm::Type *MiddleTy =
llvm::IntegerType::get(VMContext, CGF.LLVMPointerWidth);
bool InputSigned = E->getType()->isSignedIntegerType();
llvm::Value* IntResult =
Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
return Builder.CreateIntToPtr(IntResult, ConvertType(DestTy));
}
case CastExpr::CK_PointerToIntegral: {
Value *Src = Visit(const_cast<Expr*>(E));
return Builder.CreatePtrToInt(Src, ConvertType(DestTy));
}
case CastExpr::CK_ToVoid: {
CGF.EmitAnyExpr(E, 0, false, true);
return 0;
}
case CastExpr::CK_VectorSplat: {
const llvm::Type *DstTy = ConvertType(DestTy);
Value *Elt = Visit(const_cast<Expr*>(E));
// Insert the element in element zero of an undef vector
llvm::Value *UnV = llvm::UndefValue::get(DstTy);
llvm::Value *Idx =
llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 0);
UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp");
// Splat the element across to all elements
llvm::SmallVector<llvm::Constant*, 16> Args;
unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements();
for (unsigned i = 0; i < NumElements; i++)
Args.push_back(llvm::ConstantInt::get(
llvm::Type::getInt32Ty(VMContext), 0));
llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements);
llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat");
return Yay;
}
case CastExpr::CK_IntegralCast:
case CastExpr::CK_IntegralToFloating:
case CastExpr::CK_FloatingToIntegral:
case CastExpr::CK_FloatingCast:
return EmitScalarConversion(Visit(E), E->getType(), DestTy);
case CastExpr::CK_MemberPointerToBoolean:
return CGF.EvaluateExprAsBool(E);
}
// Handle cases where the source is an non-complex type.
if (!CGF.hasAggregateLLVMType(E->getType())) {
Value *Src = Visit(const_cast<Expr*>(E));
// Use EmitScalarConversion to perform the conversion.
return EmitScalarConversion(Src, E->getType(), DestTy);
}
if (E->getType()->isAnyComplexType()) {
// Handle cases where the source is a complex type.
bool IgnoreImag = true;
bool IgnoreImagAssign = true;
bool IgnoreReal = IgnoreResultAssign;
bool IgnoreRealAssign = IgnoreResultAssign;
if (DestTy->isBooleanType())
IgnoreImagAssign = IgnoreImag = false;
else if (DestTy->isVoidType()) {
IgnoreReal = IgnoreImag = false;
IgnoreRealAssign = IgnoreImagAssign = true;
}
CodeGenFunction::ComplexPairTy V
= CGF.EmitComplexExpr(E, IgnoreReal, IgnoreImag, IgnoreRealAssign,
IgnoreImagAssign);
return EmitComplexToScalarConversion(V, E->getType(), DestTy);
}
// Okay, this is a cast from an aggregate. It must be a cast to void. Just
// evaluate the result and return.
CGF.EmitAggExpr(E, 0, false, true);
return 0;
}
Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) {
return CGF.EmitCompoundStmt(*E->getSubStmt(),
!E->getType()->isVoidType()).getScalarVal();
}
Value *ScalarExprEmitter::VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) {
llvm::Value *V = CGF.GetAddrOfBlockDecl(E);
if (E->getType().isObjCGCWeak())
return CGF.CGM.getObjCRuntime().EmitObjCWeakRead(CGF, V);
return Builder.CreateLoad(V, "tmp");
}
//===----------------------------------------------------------------------===//
// Unary Operators
//===----------------------------------------------------------------------===//
Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
TestAndClearIgnoreResultAssign();
Value *Op = Visit(E->getSubExpr());
if (Op->getType()->isFPOrFPVectorTy())
return Builder.CreateFNeg(Op, "neg");
return Builder.CreateNeg(Op, "neg");
}
Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
TestAndClearIgnoreResultAssign();
Value *Op = Visit(E->getSubExpr());
return Builder.CreateNot(Op, "neg");
}
Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) {
// 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");
}
/// VisitSizeOfAlignOfExpr - Return the size or alignment of the type of
/// argument of the sizeof expression as an integer.
Value *
ScalarExprEmitter::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) {
QualType TypeToSize = E->getTypeOfArgument();
if (E->isSizeOf()) {
if (const VariableArrayType *VAT =
CGF.getContext().getAsVariableArrayType(TypeToSize)) {
if (E->isArgumentType()) {
// sizeof(type) - make sure to emit the VLA size.
CGF.EmitVLASize(TypeToSize);
} else {
// C99 6.5.3.4p2: If the argument is an expression of type
// VLA, it is evaluated.
CGF.EmitAnyExpr(E->getArgumentExpr());
}
return CGF.GetVLASize(VAT);
}
}
// 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.
Expr::EvalResult Result;
E->Evaluate(Result, CGF.getContext());
return llvm::ConstantInt::get(VMContext, Result.Val.getInt());
}
Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) {
Expr *Op = E->getSubExpr();
if (Op->getType()->isAnyComplexType())
return CGF.EmitComplexExpr(Op, false, true, false, true).first;
return Visit(Op);
}
Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) {
Expr *Op = E->getSubExpr();
if (Op->getType()->isAnyComplexType())
return CGF.EmitComplexExpr(Op, true, false, true, false).second;
// __imag on a scalar returns zero. Emit the subexpr to ensure side
// effects are evaluated, but not the actual value.
if (E->isLvalue(CGF.getContext()) == Expr::LV_Valid)
CGF.EmitLValue(Op);
else
CGF.EmitScalarExpr(Op, true);
return llvm::Constant::getNullValue(ConvertType(E->getType()));
}
Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E) {
Value* ResultAsPtr = EmitLValue(E->getSubExpr()).getAddress();
const llvm::Type* ResultType = ConvertType(E->getType());
return Builder.CreatePtrToInt(ResultAsPtr, ResultType, "offsetof");
}
//===----------------------------------------------------------------------===//
// 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.E = E;
return Result;
}
Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E,
Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) {
bool Ignore = TestAndClearIgnoreResultAssign();
QualType LHSTy = E->getLHS()->getType();
BinOpInfo OpInfo;
if (E->getComputationResultType()->isAnyComplexType()) {
// This needs to go through the complex expression emitter, but it's a tad
// complicated to do that... I'm leaving it out for now. (Note that we do
// actually need the imaginary part of the RHS for multiplication and
// division.)
CGF.ErrorUnsupported(E, "complex compound assignment");
return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
}
// 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.E = E;
// Load/convert the LHS.
LValue LHSLV = EmitCheckedLValue(E->getLHS());
OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy);
OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy,
E->getComputationLHSType());
// Expand the binary operator.
Value *Result = (this->*Func)(OpInfo);
// Convert the result back to the LHS type.
Result = EmitScalarConversion(Result, E->getComputationResultType(), LHSTy);
// 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()) {
if (!LHSLV.isVolatileQualified()) {
CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy,
&Result);
return Result;
} else
CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy);
} else
CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy);
if (Ignore)
return 0;
return EmitLoadOfLValue(LHSLV, E->getType());
}
Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) {
if (Ops.LHS->getType()->isFPOrFPVectorTy())
return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div");
else if (Ops.Ty->isUnsignedIntegerType())
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 (Ops.Ty->isUnsignedIntegerType())
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;
switch (Ops.E->getOpcode()) {
case BinaryOperator::Add:
case BinaryOperator::AddAssign:
OpID = 1;
IID = llvm::Intrinsic::sadd_with_overflow;
break;
case BinaryOperator::Sub:
case BinaryOperator::SubAssign:
OpID = 2;
IID = llvm::Intrinsic::ssub_with_overflow;
break;
case BinaryOperator::Mul:
case BinaryOperator::MulAssign:
OpID = 3;
IID = llvm::Intrinsic::smul_with_overflow;
break;
default:
assert(false && "Unsupported operation for overflow detection");
IID = 0;
}
OpID <<= 1;
OpID |= 1;
const llvm::Type *opTy = CGF.CGM.getTypes().ConvertType(Ops.Ty);
llvm::Function *intrinsic = CGF.CGM.getIntrinsic(IID, &opTy, 1);
Value *resultAndOverflow = Builder.CreateCall2(intrinsic, Ops.LHS, Ops.RHS);
Value *result = Builder.CreateExtractValue(resultAndOverflow, 0);
Value *overflow = Builder.CreateExtractValue(resultAndOverflow, 1);
// Branch in case of overflow.
llvm::BasicBlock *initialBB = Builder.GetInsertBlock();
llvm::BasicBlock *overflowBB =
CGF.createBasicBlock("overflow", CGF.CurFn);
llvm::BasicBlock *continueBB =
CGF.createBasicBlock("overflow.continue", CGF.CurFn);
Builder.CreateCondBr(overflow, overflowBB, continueBB);
// Handle overflow
Builder.SetInsertPoint(overflowBB);
// Handler is:
// long long *__overflow_handler)(long long a, long long b, char op,
// char width)
std::vector<const llvm::Type*> handerArgTypes;
handerArgTypes.push_back(llvm::Type::getInt64Ty(VMContext));
handerArgTypes.push_back(llvm::Type::getInt64Ty(VMContext));
handerArgTypes.push_back(llvm::Type::getInt8Ty(VMContext));
handerArgTypes.push_back(llvm::Type::getInt8Ty(VMContext));
llvm::FunctionType *handlerTy = llvm::FunctionType::get(
llvm::Type::getInt64Ty(VMContext), handerArgTypes, false);
llvm::Value *handlerFunction =
CGF.CGM.getModule().getOrInsertGlobal("__overflow_handler",
llvm::PointerType::getUnqual(handlerTy));
handlerFunction = Builder.CreateLoad(handlerFunction);
llvm::Value *handlerResult = Builder.CreateCall4(handlerFunction,
Builder.CreateSExt(Ops.LHS, llvm::Type::getInt64Ty(VMContext)),
Builder.CreateSExt(Ops.RHS, llvm::Type::getInt64Ty(VMContext)),
llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext), OpID),
llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext),
cast<llvm::IntegerType>(opTy)->getBitWidth()));
handlerResult = Builder.CreateTrunc(handlerResult, opTy);
Builder.CreateBr(continueBB);
// Set up the continuation
Builder.SetInsertPoint(continueBB);
// Get the correct result
llvm::PHINode *phi = Builder.CreatePHI(opTy);
phi->reserveOperandSpace(2);
phi->addIncoming(result, initialBB);
phi->addIncoming(handlerResult, overflowBB);
return phi;
}
Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) {
if (!Ops.Ty->isAnyPointerType()) {
if (CGF.getContext().getLangOptions().OverflowChecking &&
Ops.Ty->isSignedIntegerType())
return EmitOverflowCheckedBinOp(Ops);
if (Ops.LHS->getType()->isFPOrFPVectorTy())
return Builder.CreateFAdd(Ops.LHS, Ops.RHS, "add");
// Signed integer overflow is undefined behavior.
if (Ops.Ty->isSignedIntegerType())
return Builder.CreateNSWAdd(Ops.LHS, Ops.RHS, "add");
return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add");
}
if (Ops.Ty->isPointerType() &&
Ops.Ty->getAs<PointerType>()->isVariableArrayType()) {
// The amount of the addition needs to account for the VLA size
CGF.ErrorUnsupported(Ops.E, "VLA pointer addition");
}
Value *Ptr, *Idx;
Expr *IdxExp;
const PointerType *PT = Ops.E->getLHS()->getType()->getAs<PointerType>();
const ObjCObjectPointerType *OPT =
Ops.E->getLHS()->getType()->getAs<ObjCObjectPointerType>();
if (PT || OPT) {
Ptr = Ops.LHS;
Idx = Ops.RHS;
IdxExp = Ops.E->getRHS();
} else { // int + pointer
PT = Ops.E->getRHS()->getType()->getAs<PointerType>();
OPT = Ops.E->getRHS()->getType()->getAs<ObjCObjectPointerType>();
assert((PT || OPT) && "Invalid add expr");
Ptr = Ops.RHS;
Idx = Ops.LHS;
IdxExp = Ops.E->getLHS();
}
unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
if (Width < CGF.LLVMPointerWidth) {
// Zero or sign extend the pointer value based on whether the index is
// signed or not.
const llvm::Type *IdxType =
llvm::IntegerType::get(VMContext, CGF.LLVMPointerWidth);
if (IdxExp->getType()->isSignedIntegerType())
Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext");
else
Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext");
}
const QualType ElementType = PT ? PT->getPointeeType() : OPT->getPointeeType();
// Handle interface types, which are not represented with a concrete type.
if (const ObjCInterfaceType *OIT = dyn_cast<ObjCInterfaceType>(ElementType)) {
llvm::Value *InterfaceSize =
llvm::ConstantInt::get(Idx->getType(),
CGF.getContext().getTypeSizeInChars(OIT).getQuantity());
Idx = Builder.CreateMul(Idx, InterfaceSize);
const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
Value *Casted = Builder.CreateBitCast(Ptr, i8Ty);
Value *Res = Builder.CreateGEP(Casted, Idx, "add.ptr");
return Builder.CreateBitCast(Res, Ptr->getType());
}
// 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()) {
const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
Value *Casted = Builder.CreateBitCast(Ptr, i8Ty);
Value *Res = Builder.CreateGEP(Casted, Idx, "add.ptr");
return Builder.CreateBitCast(Res, Ptr->getType());
}
return Builder.CreateInBoundsGEP(Ptr, Idx, "add.ptr");
}
Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) {
if (!isa<llvm::PointerType>(Ops.LHS->getType())) {
if (CGF.getContext().getLangOptions().OverflowChecking
&& Ops.Ty->isSignedIntegerType())
return EmitOverflowCheckedBinOp(Ops);
if (Ops.LHS->getType()->isFPOrFPVectorTy())
return Builder.CreateFSub(Ops.LHS, Ops.RHS, "sub");
// Signed integer overflow is undefined behavior.
if (Ops.Ty->isSignedIntegerType())
return Builder.CreateNSWSub(Ops.LHS, Ops.RHS, "sub");
return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub");
}
if (Ops.E->getLHS()->getType()->isPointerType() &&
Ops.E->getLHS()->getType()->getAs<PointerType>()->isVariableArrayType()) {
// The amount of the addition needs to account for the VLA size for
// ptr-int
// The amount of the division needs to account for the VLA size for
// ptr-ptr.
CGF.ErrorUnsupported(Ops.E, "VLA pointer subtraction");
}
const QualType LHSType = Ops.E->getLHS()->getType();
const QualType LHSElementType = LHSType->getPointeeType();
if (!isa<llvm::PointerType>(Ops.RHS->getType())) {
// pointer - int
Value *Idx = Ops.RHS;
unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
if (Width < CGF.LLVMPointerWidth) {
// Zero or sign extend the pointer value based on whether the index is
// signed or not.
const llvm::Type *IdxType =
llvm::IntegerType::get(VMContext, CGF.LLVMPointerWidth);
if (Ops.E->getRHS()->getType()->isSignedIntegerType())
Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext");
else
Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext");
}
Idx = Builder.CreateNeg(Idx, "sub.ptr.neg");
// Handle interface types, which are not represented with a concrete type.
if (const ObjCInterfaceType *OIT =
dyn_cast<ObjCInterfaceType>(LHSElementType)) {
llvm::Value *InterfaceSize =
llvm::ConstantInt::get(Idx->getType(),
CGF.getContext().
getTypeSizeInChars(OIT).getQuantity());
Idx = Builder.CreateMul(Idx, InterfaceSize);
const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty);
Value *Res = Builder.CreateGEP(LHSCasted, Idx, "add.ptr");
return Builder.CreateBitCast(Res, Ops.LHS->getType());
}
// 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 (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) {
const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty);
Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr");
return Builder.CreateBitCast(Res, Ops.LHS->getType());
}
return Builder.CreateInBoundsGEP(Ops.LHS, Idx, "sub.ptr");
} else {
// pointer - pointer
Value *LHS = Ops.LHS;
Value *RHS = Ops.RHS;
CharUnits ElementSize;
// Handle GCC extension for pointer arithmetic on void* and function pointer
// types.
if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) {
ElementSize = CharUnits::One();
} else {
ElementSize = CGF.getContext().getTypeSizeInChars(LHSElementType);
}
const llvm::Type *ResultType = ConvertType(Ops.Ty);
LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast");
RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub");
// Optimize out the shift for element size of 1.
if (ElementSize.isOne())
return BytesBetween;
// 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.
Value *BytesPerElt =
llvm::ConstantInt::get(ResultType, ElementSize.getQuantity());
return Builder.CreateExactSDiv(BytesBetween, BytesPerElt, "sub.ptr.div");
}
}
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");
if (CGF.CatchUndefined
&& isa<llvm::IntegerType>(Ops.LHS->getType())) {
unsigned Width = cast<llvm::IntegerType>(Ops.LHS->getType())->getBitWidth();
llvm::BasicBlock *Cont = CGF.createBasicBlock("cont");
CGF.Builder.CreateCondBr(Builder.CreateICmpULT(RHS,
llvm::ConstantInt::get(RHS->getType(), Width)),
Cont, CGF.getTrapBB());
CGF.EmitBlock(Cont);
}
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");
if (CGF.CatchUndefined
&& isa<llvm::IntegerType>(Ops.LHS->getType())) {
unsigned Width = cast<llvm::IntegerType>(Ops.LHS->getType())->getBitWidth();
llvm::BasicBlock *Cont = CGF.createBasicBlock("cont");
CGF.Builder.CreateCondBr(Builder.CreateICmpULT(RHS,
llvm::ConstantInt::get(RHS->getType(), Width)),
Cont, CGF.getTrapBB());
CGF.EmitBlock(Cont);
}
if (Ops.Ty->isUnsignedIntegerType())
return Builder.CreateLShr(Ops.LHS, RHS, "shr");
return Builder.CreateAShr(Ops.LHS, RHS, "shr");
}
Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc,
unsigned SICmpOpc, unsigned FCmpOpc) {
TestAndClearIgnoreResultAssign();
Value *Result;
QualType LHSTy = E->getLHS()->getType();
if (LHSTy->isMemberFunctionPointerType()) {
Value *LHSPtr = CGF.EmitAnyExprToTemp(E->getLHS()).getAggregateAddr();
Value *RHSPtr = CGF.EmitAnyExprToTemp(E->getRHS()).getAggregateAddr();
llvm::Value *LHSFunc = Builder.CreateStructGEP(LHSPtr, 0);
LHSFunc = Builder.CreateLoad(LHSFunc);
llvm::Value *RHSFunc = Builder.CreateStructGEP(RHSPtr, 0);
RHSFunc = Builder.CreateLoad(RHSFunc);
Value *ResultF = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
LHSFunc, RHSFunc, "cmp.func");
Value *NullPtr = llvm::Constant::getNullValue(LHSFunc->getType());
Value *ResultNull = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
LHSFunc, NullPtr, "cmp.null");
llvm::Value *LHSAdj = Builder.CreateStructGEP(LHSPtr, 1);
LHSAdj = Builder.CreateLoad(LHSAdj);
llvm::Value *RHSAdj = Builder.CreateStructGEP(RHSPtr, 1);
RHSAdj = Builder.CreateLoad(RHSAdj);
Value *ResultA = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
LHSAdj, RHSAdj, "cmp.adj");
if (E->getOpcode() == BinaryOperator::EQ) {
Result = Builder.CreateOr(ResultNull, ResultA, "or.na");
Result = Builder.CreateAnd(Result, ResultF, "and.f");
} else {
assert(E->getOpcode() == BinaryOperator::NE &&
"Member pointer comparison other than == or != ?");
Result = Builder.CreateAnd(ResultNull, ResultA, "and.na");
Result = Builder.CreateOr(Result, ResultF, "or.f");
}
} else if (!LHSTy->isAnyComplexType()) {
Value *LHS = Visit(E->getLHS());
Value *RHS = Visit(E->getRHS());
if (LHS->getType()->isFPOrFPVectorTy()) {
Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc,
LHS, RHS, "cmp");
} else if (LHSTy->isSignedIntegerType()) {
Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc,
LHS, RHS, "cmp");
} else {
// Unsigned integers and pointers.
Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)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 = CGF.EmitComplexExpr(E->getLHS());
CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS());
QualType CETy = LHSTy->getAs<ComplexType>()->getElementType();
Value *ResultR, *ResultI;
if (CETy->isRealFloatingType()) {
ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc,
LHS.first, RHS.first, "cmp.r");
ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)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((llvm::ICmpInst::Predicate)UICmpOpc,
LHS.first, RHS.first, "cmp.r");
ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
LHS.second, RHS.second, "cmp.i");
}
if (E->getOpcode() == BinaryOperator::EQ) {
Result = Builder.CreateAnd(ResultR, ResultI, "and.ri");
} else {
assert(E->getOpcode() == BinaryOperator::NE &&
"Complex comparison other than == or != ?");
Result = Builder.CreateOr(ResultR, ResultI, "or.ri");
}
}
return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType());
}
Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) {
bool Ignore = TestAndClearIgnoreResultAssign();
// __block variables need to have the rhs evaluated first, plus this should
// improve codegen just a little.
Value *RHS = Visit(E->getRHS());
LValue LHS = EmitCheckedLValue(E->getLHS());
// 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()) {
if (!LHS.isVolatileQualified()) {
CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType(),
&RHS);
return RHS;
} else
CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType());
} else
CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType());
if (Ignore)
return 0;
return EmitLoadOfLValue(LHS, E->getType());
}
Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) {
const 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.
if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) {
if (Cond == 1) { // If we have 1 && X, just emit X.
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");
// Branch on the LHS first. If it is false, go to the failure (cont) block.
CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock);
// 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),
"", ContBlock);
PN->reserveOperandSpace(2); // Normal case, two inputs.
for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock);
PI != PE; ++PI)
PN->addIncoming(llvm::ConstantInt::getFalse(VMContext), *PI);
CGF.BeginConditionalBranch();
CGF.EmitBlock(RHSBlock);
Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
CGF.EndConditionalBranch();
// 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, "land.ext");
}
Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) {
const 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.
if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) {
if (Cond == -1) { // If we have 0 || X, just emit X.
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");
// Branch on the LHS first. If it is true, go to the success (cont) block.
CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock);
// 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),
"", ContBlock);
PN->reserveOperandSpace(2); // Normal case, two inputs.
for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock);
PI != PE; ++PI)
PN->addIncoming(llvm::ConstantInt::getTrue(VMContext), *PI);
CGF.BeginConditionalBranch();
// Emit the RHS condition as a bool value.
CGF.EmitBlock(RHSBlock);
Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
CGF.EndConditionalBranch();
// 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.EmitStmt(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) {
if (const ParenExpr *PE = dyn_cast<ParenExpr>(E))
return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr(), CGF);
// TODO: Allow anything we can constant fold to an integer or fp constant.
if (isa<IntegerLiteral>(E) || isa<CharacterLiteral>(E) ||
isa<FloatingLiteral>(E))
return true;
// Non-volatile automatic variables too, to get "cond ? X : Y" where
// X and Y are local variables.
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl()))
if (VD->hasLocalStorage() && !(CGF.getContext()
.getCanonicalType(VD->getType())
.isVolatileQualified()))
return true;
return false;
}
Value *ScalarExprEmitter::
VisitConditionalOperator(const ConditionalOperator *E) {
TestAndClearIgnoreResultAssign();
// If the condition constant folds and can be elided, try to avoid emitting
// the condition and the dead arm.
if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getCond())){
Expr *Live = E->getLHS(), *Dead = E->getRHS();
if (Cond == -1)
std::swap(Live, Dead);
// If the dead side doesn't have labels we need, and if the Live side isn't
// the gnu missing ?: extension (which we could handle, but don't bother
// to), just emit the Live part.
if ((!Dead || !CGF.ContainsLabel(Dead)) && // No labels in dead part
Live) // Live part isn't missing.
return Visit(Live);
}
// 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 (E->getLHS() && isCheapEnoughToEvaluateUnconditionally(E->getLHS(),
CGF) &&
isCheapEnoughToEvaluateUnconditionally(E->getRHS(), CGF)) {
llvm::Value *CondV = CGF.EvaluateExprAsBool(E->getCond());
llvm::Value *LHS = Visit(E->getLHS());
llvm::Value *RHS = Visit(E->getRHS());
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");
Value *CondVal = 0;
// If we don't have the GNU missing condition extension, emit a branch on bool
// the normal way.
if (E->getLHS()) {
// Otherwise, just use EmitBranchOnBoolExpr to get small and simple code for
// the branch on bool.
CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
} else {
// Otherwise, for the ?: extension, evaluate the conditional and then
// convert it to bool the hard way. We do this explicitly because we need
// the unconverted value for the missing middle value of the ?:.
CondVal = CGF.EmitScalarExpr(E->getCond());
// In some cases, EmitScalarConversion will delete the "CondVal" expression
// if there are no extra uses (an optimization). Inhibit this by making an
// extra dead use, because we're going to add a use of CondVal later. We
// don't use the builder for this, because we don't want it to get optimized
// away. This leaves dead code, but the ?: extension isn't common.
new llvm::BitCastInst(CondVal, CondVal->getType(), "dummy?:holder",
Builder.GetInsertBlock());
Value *CondBoolVal =
CGF.EmitScalarConversion(CondVal, E->getCond()->getType(),
CGF.getContext().BoolTy);
Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock);
}
CGF.BeginConditionalBranch();
CGF.EmitBlock(LHSBlock);
// Handle the GNU extension for missing LHS.
Value *LHS;
if (E->getLHS())
LHS = Visit(E->getLHS());
else // Perform promotions, to handle cases like "short ?: int"
LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType());
CGF.EndConditionalBranch();
LHSBlock = Builder.GetInsertBlock();
CGF.EmitBranch(ContBlock);
CGF.BeginConditionalBranch();
CGF.EmitBlock(RHSBlock);
Value *RHS = Visit(E->getRHS());
CGF.EndConditionalBranch();
RHSBlock = Builder.GetInsertBlock();
CGF.EmitBranch(ContBlock);
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(), "cond");
PN->reserveOperandSpace(2);
PN->addIncoming(LHS, LHSBlock);
PN->addIncoming(RHS, RHSBlock);
return PN;
}
Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) {
return Visit(E->getChosenSubExpr(CGF.getContext()));
}
Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
// If EmitVAArg fails, we fall back to the LLVM instruction.
if (!ArgPtr)
return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType()));
// FIXME Volatility.
return Builder.CreateLoad(ArgPtr);
}
Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *BE) {
return CGF.BuildBlockLiteralTmp(BE);
}
//===----------------------------------------------------------------------===//
// Entry Point into this File
//===----------------------------------------------------------------------===//
/// EmitScalarExpr - Emit the computation of the specified expression of scalar
/// type, ignoring the result.
Value *CodeGenFunction::EmitScalarExpr(const Expr *E, bool IgnoreResultAssign) {
assert(E && !hasAggregateLLVMType(E->getType()) &&
"Invalid scalar expression to emit");
return ScalarExprEmitter(*this, IgnoreResultAssign)
.Visit(const_cast<Expr*>(E));
}
/// EmitScalarConversion - 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) {
assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) &&
"Invalid scalar expression to emit");
return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy);
}
/// EmitComplexToScalarConversion - 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) {
assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) &&
"Invalid complex -> scalar conversion");
return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy,
DstTy);
}
LValue CodeGenFunction::EmitObjCIsaExpr(const ObjCIsaExpr *E) {
llvm::Value *V;
// object->isa or (*object).isa
// Generate code as for: *(Class*)object
// build Class* type
const llvm::Type *ClassPtrTy = ConvertType(E->getType());
Expr *BaseExpr = E->getBase();
if (BaseExpr->isLvalue(getContext()) != Expr::LV_Valid) {
V = CreateTempAlloca(ClassPtrTy, "resval");
llvm::Value *Src = EmitScalarExpr(BaseExpr);
Builder.CreateStore(Src, V);
LValue LV = LValue::MakeAddr(V, MakeQualifiers(E->getType()));
V = ScalarExprEmitter(*this).EmitLoadOfLValue(LV, E->getType());
}
else {
if (E->isArrow())
V = ScalarExprEmitter(*this).EmitLoadOfLValue(BaseExpr);
else
V = EmitLValue(BaseExpr).getAddress();
}
// build Class* type
ClassPtrTy = ClassPtrTy->getPointerTo();
V = Builder.CreateBitCast(V, ClassPtrTy);
LValue LV = LValue::MakeAddr(V, MakeQualifiers(E->getType()));
return LV;
}