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clang-1/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 "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/Compiler.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 VISIBILITY_HIDDEN ScalarExprEmitter
: public StmtVisitor<ScalarExprEmitter, Value*> {
CodeGenFunction &CGF;
CGBuilderTy &Builder;
public:
ScalarExprEmitter(CodeGenFunction &cgf) : CGF(cgf),
Builder(CGF.Builder) {
}
//===--------------------------------------------------------------------===//
// Utilities
//===--------------------------------------------------------------------===//
const llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); }
LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(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(EmitLValue(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(E->getValue());
}
Value *VisitFloatingLiteral(const FloatingLiteral *E) {
return llvm::ConstantFP::get(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 =
llvm::ConstantInt::get(llvm::Type::Int32Ty,
CGF.GetIDForAddrOfLabel(E->getLabel()));
return Builder.CreateIntToPtr(V, ConvertType(E->getType()));
}
// l-values.
Value *VisitDeclRefExpr(DeclRefExpr *E) {
if (const EnumConstantDecl *EC = dyn_cast<EnumConstantDecl>(E->getDecl()))
return llvm::ConstantInt::get(EC->getInitVal());
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 *VisitObjCKVCRefExpr(ObjCKVCRefExpr *E) {
return EmitLoadOfLValue(E);
}
Value *VisitObjCMessageExpr(ObjCMessageExpr *E) {
return CGF.EmitObjCMessageExpr(E).getScalarVal();
}
Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E);
Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E);
Value *VisitMemberExpr(Expr *E) { return EmitLoadOfLValue(E); }
Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); }
Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
return EmitLoadOfLValue(E);
}
Value *VisitStringLiteral(Expr *E) { return EmitLValue(E).getAddress(); }
Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
return EmitLValue(E).getAddress();
}
Value *VisitPredefinedExpr(Expr *E) { return EmitLValue(E).getAddress(); }
Value *VisitInitListExpr(InitListExpr *E) {
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 NumVectorElements = VType->getNumElements();
const llvm::Type *ElementType = VType->getElementType();
// Emit individual vector element stores.
llvm::Value *V = llvm::UndefValue::get(VType);
// Emit initializers
unsigned i;
for (i = 0; i < NumInitElements; ++i) {
Value *NewV = Visit(E->getInit(i));
Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
V = Builder.CreateInsertElement(V, NewV, Idx);
}
// Emit remaining default initializers
for (/* Do not initialize i*/; i < NumVectorElements; ++i) {
Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
llvm::Value *NewV = llvm::Constant::getNullValue(ElementType);
V = Builder.CreateInsertElement(V, NewV, Idx);
}
return V;
}
Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
return llvm::Constant::getNullValue(ConvertType(E->getType()));
}
Value *VisitImplicitCastExpr(const ImplicitCastExpr *E);
Value *VisitCastExpr(const CastExpr *E) {
return EmitCastExpr(E->getSubExpr(), E->getType());
}
Value *EmitCastExpr(const Expr *E, QualType T);
Value *VisitCallExpr(const CallExpr *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);
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) {
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();
}
// Binary Operators.
Value *EmitMul(const BinOpInfo &Ops) {
if (CGF.getContext().getLangOptions().OverflowChecking
&& Ops.Ty->isSignedIntegerType())
return EmitOverflowCheckedBinOp(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);
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);
// 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");
}
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::Int1Ty) {
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;
// 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(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() && !isa<VectorType>(SrcType)) {
// Cast the scalar to element type
QualType EltTy = DstType->getAsExtVectorType()->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::Int32Ty, 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::Int32Ty, 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()->isFloatingPoint() && "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->isFloatingPoint() && "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->getAsComplexType()->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::VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
// 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::Int32Ty, IdxSigned,
"vecidxcast");
return Builder.CreateExtractElement(Base, Idx, "vecext");
}
/// VisitImplicitCastExpr - Implicit casts are the same as normal casts, but
/// also handle things like function to pointer-to-function decay, and array to
/// pointer decay.
Value *ScalarExprEmitter::VisitImplicitCastExpr(const ImplicitCastExpr *E) {
const Expr *Op = E->getSubExpr();
// If this is due to array->pointer conversion, emit the array expression as
// an l-value.
if (Op->getType()->isArrayType()) {
Value *V = EmitLValue(Op).getAddress(); // Bitfields can't be arrays.
// Note that VLA pointers are always decayed, so we don't need to do
// anything here.
if (!Op->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");
}
// The resultant pointer type can be implicitly casted to other pointer
// types as well (e.g. void*) and can be implicitly converted to integer.
const llvm::Type *DestTy = ConvertType(E->getType());
if (V->getType() != DestTy) {
if (isa<llvm::PointerType>(DestTy))
V = Builder.CreateBitCast(V, DestTy, "ptrconv");
else {
assert(isa<llvm::IntegerType>(DestTy) && "Unknown array decay");
V = Builder.CreatePtrToInt(V, DestTy, "ptrconv");
}
}
return V;
}
return EmitCastExpr(Op, E->getType());
}
// 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(const Expr *E, QualType DestTy) {
// 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.
return EmitComplexToScalarConversion(CGF.EmitComplexExpr(E), 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);
return 0;
}
Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) {
return CGF.EmitCompoundStmt(*E->getSubStmt(),
!E->getType()->isVoidType()).getScalarVal();
}
Value *ScalarExprEmitter::VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) {
return Builder.CreateLoad(CGF.GetAddrOfBlockDecl(E), false, "tmp");
}
//===----------------------------------------------------------------------===//
// Unary Operators
//===----------------------------------------------------------------------===//
Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E,
bool isInc, bool isPre) {
LValue LV = EmitLValue(E->getSubExpr());
QualType ValTy = E->getSubExpr()->getType();
Value *InVal = CGF.EmitLoadOfLValue(LV, ValTy).getScalarVal();
int AmountVal = isInc ? 1 : -1;
if (ValTy->isPointerType() &&
ValTy->getAsPointerType()->isVariableArrayType()) {
// The amount of the addition/subtraction needs to account for the VLA size
CGF.ErrorUnsupported(E, "VLA pointer inc/dec");
}
Value *NextVal;
if (const llvm::PointerType *PT =
dyn_cast<llvm::PointerType>(InVal->getType())) {
llvm::Constant *Inc =llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal);
if (!isa<llvm::FunctionType>(PT->getElementType())) {
NextVal = Builder.CreateGEP(InVal, Inc, "ptrincdec");
} else {
const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
NextVal = Builder.CreateBitCast(InVal, i8Ty, "tmp");
NextVal = Builder.CreateGEP(NextVal, Inc, "ptrincdec");
NextVal = Builder.CreateBitCast(NextVal, InVal->getType());
}
} else if (InVal->getType() == llvm::Type::Int1Ty && isInc) {
// Bool++ is an interesting case, 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.
NextVal = llvm::ConstantInt::getTrue();
} else {
// Add the inc/dec to the real part.
if (isa<llvm::IntegerType>(InVal->getType()))
NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal);
else if (InVal->getType() == llvm::Type::FloatTy)
NextVal =
llvm::ConstantFP::get(llvm::APFloat(static_cast<float>(AmountVal)));
else if (InVal->getType() == llvm::Type::DoubleTy)
NextVal =
llvm::ConstantFP::get(llvm::APFloat(static_cast<double>(AmountVal)));
else {
llvm::APFloat F(static_cast<float>(AmountVal));
bool ignored;
F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero,
&ignored);
NextVal = llvm::ConstantFP::get(F);
}
NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
}
// Store the updated result through the lvalue.
if (LV.isBitfield())
CGF.EmitStoreThroughBitfieldLValue(RValue::get(NextVal), LV, ValTy,
&NextVal);
else
CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV, ValTy);
// If this is a postinc, return the value read from memory, otherwise use the
// updated value.
return isPre ? NextVal : InVal;
}
Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
Value *Op = Visit(E->getSubExpr());
return Builder.CreateNeg(Op, "neg");
}
Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
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 int.
return Builder.CreateZExt(BoolVal, CGF.LLVMIntTy, "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);
}
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(Result.Val.getInt());
}
Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) {
Expr *Op = E->getSubExpr();
if (Op->getType()->isAnyComplexType())
return CGF.EmitComplexExpr(Op).first;
return Visit(Op);
}
Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) {
Expr *Op = E->getSubExpr();
if (Op->getType()->isAnyComplexType())
return CGF.EmitComplexExpr(Op).second;
// __imag on a scalar returns zero. Emit it the subexpr to ensure side
// effects are evaluated.
CGF.EmitScalarExpr(Op);
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) {
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 &)) {
QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->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()));
}
// Load/convert the LHS.
LValue LHSLV = EmitLValue(E->getLHS());
OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy);
OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy,
E->getComputationLHSType());
// Emit the RHS.
OpInfo.RHS = Visit(E->getRHS());
OpInfo.Ty = E->getComputationResultType();
OpInfo.E = E;
// 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())
CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy,
&Result);
else
CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy);
return Result;
}
Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) {
if (Ops.LHS->getType()->isFPOrFPVector())
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::Int64Ty);
handerArgTypes.push_back(llvm::Type::Int64Ty);
handerArgTypes.push_back(llvm::Type::Int8Ty);
handerArgTypes.push_back(llvm::Type::Int8Ty);
llvm::FunctionType *handlerTy = llvm::FunctionType::get(llvm::Type::Int64Ty,
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::Int64Ty),
Builder.CreateSExt(Ops.RHS, llvm::Type::Int64Ty),
llvm::ConstantInt::get(llvm::Type::Int8Ty, OpID),
llvm::ConstantInt::get(llvm::Type::Int8Ty,
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->isPointerType()) {
if (CGF.getContext().getLangOptions().OverflowChecking
&& Ops.Ty->isSignedIntegerType())
return EmitOverflowCheckedBinOp(Ops);
return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add");
}
if (Ops.Ty->getAsPointerType()->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;
if ((PT = Ops.E->getLHS()->getType()->getAsPointerType())) {
Ptr = Ops.LHS;
Idx = Ops.RHS;
IdxExp = Ops.E->getRHS();
} else { // int + pointer
PT = Ops.E->getRHS()->getType()->getAsPointerType();
assert(PT && "Invalid add expr");
Ptr = Ops.RHS;
Idx = Ops.LHS;
IdxExp = Ops.E->getLHS();
}
unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
// Only 32 and 64 are valid index widths. So if a target has shorter
// pointe width, extend to 32 at least.
unsigned IdxValidWidth
= (CGF.LLVMPointerWidth < 32) ? 32 : CGF.LLVMPointerWidth;
if (Width < IdxValidWidth) {
// Zero or sign extend the pointer value based on whether the index is
// signed or not.
const llvm::Type *IdxType = llvm::IntegerType::get(IdxValidWidth);
if (IdxExp->getType()->isSignedIntegerType())
Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext");
else
Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext");
}
// 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.
const QualType ElementType = PT->getPointeeType();
if (ElementType->isVoidType() || ElementType->isFunctionType()) {
const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
Value *Casted = Builder.CreateBitCast(Ptr, i8Ty);
Value *Res = Builder.CreateGEP(Casted, Idx, "sub.ptr");
return Builder.CreateBitCast(Res, Ptr->getType());
}
return Builder.CreateGEP(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);
return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub");
}
if (Ops.E->getLHS()->getType()->getAsPointerType()->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->getAsPointerType()->getPointeeType();
if (!isa<llvm::PointerType>(Ops.RHS->getType())) {
// pointer - int
Value *Idx = Ops.RHS;
unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
unsigned IdxValidWidth
= (CGF.LLVMPointerWidth < 32) ? 32 : CGF.LLVMPointerWidth;
if (Width < IdxValidWidth) {
// Zero or sign extend the pointer value based on whether the index is
// signed or not.
const llvm::Type *IdxType = llvm::IntegerType::get(IdxValidWidth);
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");
// 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::PointerType::getUnqual(llvm::Type::Int8Ty);
Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty);
Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr");
return Builder.CreateBitCast(Res, Ops.LHS->getType());
}
return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr");
} else {
// pointer - pointer
Value *LHS = Ops.LHS;
Value *RHS = Ops.RHS;
uint64_t ElementSize;
// Handle GCC extension for pointer arithmetic on void* and function pointer
// types.
if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) {
ElementSize = 1;
} else {
ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8;
}
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 == 1)
return BytesBetween;
// HACK: LLVM doesn't have an divide instruction that 'knows' there is no
// remainder. As such, we handle common power-of-two cases here to generate
// better code. See PR2247.
if (llvm::isPowerOf2_64(ElementSize)) {
Value *ShAmt =
llvm::ConstantInt::get(ResultType, llvm::Log2_64(ElementSize));
return Builder.CreateAShr(BytesBetween, ShAmt, "sub.ptr.shr");
}
// Otherwise, do a full sdiv.
Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize);
return Builder.CreateSDiv(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");
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 (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) {
Value *Result;
QualType LHSTy = E->getLHS()->getType();
if (!LHSTy->isAnyComplexType() && !LHSTy->isVectorType()) {
Value *LHS = Visit(E->getLHS());
Value *RHS = Visit(E->getRHS());
if (LHS->getType()->isFloatingPoint()) {
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");
}
} else if (LHSTy->isVectorType()) {
Value *LHS = Visit(E->getLHS());
Value *RHS = Visit(E->getRHS());
if (LHS->getType()->isFPOrFPVector()) {
Result = Builder.CreateVFCmp((llvm::CmpInst::Predicate)FCmpOpc,
LHS, RHS, "cmp");
} else if (LHSTy->isUnsignedIntegerType()) {
Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)UICmpOpc,
LHS, RHS, "cmp");
} else {
// Signed integers and pointers.
Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)SICmpOpc,
LHS, RHS, "cmp");
}
return Result;
} 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->getAsComplexType()->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) {
LValue LHS = EmitLValue(E->getLHS());
Value *RHS = Visit(E->getRHS());
// 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, E->getType(),
&RHS);
else
CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType());
// Return the RHS.
return RHS;
}
Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) {
// 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.
return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "land.ext");
}
// 0 && RHS: If it is safe, just elide the RHS, and return 0.
if (!CGF.ContainsLabel(E->getRHS()))
return llvm::Constant::getNullValue(CGF.LLVMIntTy);
}
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::Int1Ty, "", 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(), *PI);
CGF.EmitBlock(RHSBlock);
Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
// 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.CreateZExt(PN, CGF.LLVMIntTy, "land.ext");
}
Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) {
// 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.
return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "lor.ext");
}
// 1 || RHS: If it is safe, just elide the RHS, and return 1.
if (!CGF.ContainsLabel(E->getRHS()))
return llvm::ConstantInt::get(CGF.LLVMIntTy, 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::Int1Ty, "", 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(), *PI);
// Emit the RHS condition as a bool value.
CGF.EmitBlock(RHSBlock);
Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
// 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.CreateZExt(PN, CGF.LLVMIntTy, "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) {
if (const ParenExpr *PE = dyn_cast<ParenExpr>(E))
return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr());
// 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() && !VD->getType().isVolatileQualified())
return true;
return false;
}
Value *ScalarExprEmitter::
VisitConditionalOperator(const ConditionalOperator *E) {
// 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()) &&
isCheapEnoughToEvaluateUnconditionally(E->getRHS())) {
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.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());
LHSBlock = Builder.GetInsertBlock();
CGF.EmitBranch(ContBlock);
CGF.EmitBlock(RHSBlock);
Value *RHS = Visit(E->getRHS());
RHSBlock = Builder.GetInsertBlock();
CGF.EmitBranch(ContBlock);
CGF.EmitBlock(ContBlock);
if (!LHS || !RHS) {
assert(E->getType()->isVoidType() && "Non-void value should have a value");
return 0;
}
// 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()));
return Builder.CreateLoad(ArgPtr);
}
Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *BE) {
return CGF.BuildBlockLiteralTmp(BE);
}
//===----------------------------------------------------------------------===//
// Entry Point into this File
//===----------------------------------------------------------------------===//
/// EmitComplexExpr - Emit the computation of the specified expression of
/// complex type, ignoring the result.
Value *CodeGenFunction::EmitScalarExpr(const Expr *E) {
assert(E && !hasAggregateLLVMType(E->getType()) &&
"Invalid scalar expression to emit");
return ScalarExprEmitter(*this).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);
}
Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) {
assert(V1->getType() == V2->getType() &&
"Vector operands must be of the same type");
unsigned NumElements =
cast<llvm::VectorType>(V1->getType())->getNumElements();
va_list va;
va_start(va, V2);
llvm::SmallVector<llvm::Constant*, 16> Args;
for (unsigned i = 0; i < NumElements; i++) {
int n = va_arg(va, int);
assert(n >= 0 && n < (int)NumElements * 2 &&
"Vector shuffle index out of bounds!");
Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, n));
}
const char *Name = va_arg(va, const char *);
va_end(va);
llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements);
return Builder.CreateShuffleVector(V1, V2, Mask, Name);
}
llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals,
unsigned NumVals, bool isSplat) {
llvm::Value *Vec
= llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals));
for (unsigned i = 0, e = NumVals; i != e; ++i) {
llvm::Value *Val = isSplat ? Vals[0] : Vals[i];
llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp");
}
return Vec;
}
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