| //===--- CGExpr.cpp - Emit LLVM Code from Expressions ---------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by Chris Lattner and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This contains code to emit Expr nodes as LLVM code. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CodeGenFunction.h" |
| #include "CodeGenModule.h" |
| #include "clang/AST/AST.h" |
| #include "clang/Lex/IdentifierTable.h" |
| #include "llvm/Constants.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/Function.h" |
| #include "llvm/GlobalVariable.h" |
| #include "llvm/Support/MathExtras.h" |
| using namespace clang; |
| using namespace CodeGen; |
| |
| //===--------------------------------------------------------------------===// |
| // Miscellaneous Helper Methods |
| //===--------------------------------------------------------------------===// |
| |
| /// CreateTempAlloca - This creates a alloca and inserts it into the entry |
| /// block. |
| llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty, |
| const char *Name) { |
| return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt); |
| } |
| |
| /// EvaluateExprAsBool - Perform the usual unary conversions on the specified |
| /// expression and compare the result against zero, returning an Int1Ty value. |
| llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) { |
| QualType BoolTy = getContext().BoolTy; |
| if (!E->getType()->isComplexType()) |
| return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy); |
| |
| return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // LValue Expression Emission |
| //===----------------------------------------------------------------------===// |
| |
| /// EmitLValue - Emit code to compute a designator that specifies the location |
| /// of the expression. |
| /// |
| /// This can return one of two things: a simple address or a bitfield |
| /// reference. In either case, the LLVM Value* in the LValue structure is |
| /// guaranteed to be an LLVM pointer type. |
| /// |
| /// If this returns a bitfield reference, nothing about the pointee type of |
| /// the LLVM value is known: For example, it may not be a pointer to an |
| /// integer. |
| /// |
| /// If this returns a normal address, and if the lvalue's C type is fixed |
| /// size, this method guarantees that the returned pointer type will point to |
| /// an LLVM type of the same size of the lvalue's type. If the lvalue has a |
| /// variable length type, this is not possible. |
| /// |
| LValue CodeGenFunction::EmitLValue(const Expr *E) { |
| switch (E->getStmtClass()) { |
| default: { |
| fprintf(stderr, "Unimplemented lvalue expr!\n"); |
| E->dump(); |
| llvm::Type *Ty = llvm::PointerType::get(ConvertType(E->getType())); |
| return LValue::MakeAddr(llvm::UndefValue::get(Ty)); |
| } |
| |
| case Expr::DeclRefExprClass: return EmitDeclRefLValue(cast<DeclRefExpr>(E)); |
| case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr()); |
| case Expr::PreDefinedExprClass: |
| return EmitPreDefinedLValue(cast<PreDefinedExpr>(E)); |
| case Expr::StringLiteralClass: |
| return EmitStringLiteralLValue(cast<StringLiteral>(E)); |
| |
| case Expr::UnaryOperatorClass: |
| return EmitUnaryOpLValue(cast<UnaryOperator>(E)); |
| case Expr::ArraySubscriptExprClass: |
| return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E)); |
| case Expr::OCUVectorElementExprClass: |
| return EmitOCUVectorElementExpr(cast<OCUVectorElementExpr>(E)); |
| } |
| } |
| |
| /// EmitLoadOfLValue - Given an expression that represents a value lvalue, |
| /// this method emits the address of the lvalue, then loads the result as an |
| /// rvalue, returning the rvalue. |
| RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) { |
| if (LV.isSimple()) { |
| llvm::Value *Ptr = LV.getAddress(); |
| const llvm::Type *EltTy = |
| cast<llvm::PointerType>(Ptr->getType())->getElementType(); |
| |
| // Simple scalar l-value. |
| if (EltTy->isFirstClassType()) |
| return RValue::get(Builder.CreateLoad(Ptr, "tmp")); |
| |
| assert(ExprType->isFunctionType() && "Unknown scalar value"); |
| return RValue::get(Ptr); |
| } |
| |
| if (LV.isVectorElt()) { |
| llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(), "tmp"); |
| return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(), |
| "vecext")); |
| } |
| |
| // If this is a reference to a subset of the elements of a vector, either |
| // shuffle the input or extract/insert them as appropriate. |
| if (LV.isOCUVectorElt()) |
| return EmitLoadOfOCUElementLValue(LV, ExprType); |
| |
| assert(0 && "Bitfield ref not impl!"); |
| } |
| |
| // If this is a reference to a subset of the elements of a vector, either |
| // shuffle the input or extract/insert them as appropriate. |
| RValue CodeGenFunction::EmitLoadOfOCUElementLValue(LValue LV, |
| QualType ExprType) { |
| llvm::Value *Vec = Builder.CreateLoad(LV.getOCUVectorAddr(), "tmp"); |
| |
| unsigned EncFields = LV.getOCUVectorElts(); |
| |
| // If the result of the expression is a non-vector type, we must be |
| // extracting a single element. Just codegen as an extractelement. |
| const VectorType *ExprVT = ExprType->getAsVectorType(); |
| if (!ExprVT) { |
| unsigned InIdx = OCUVectorElementExpr::getAccessedFieldNo(0, EncFields); |
| llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx); |
| return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp")); |
| } |
| |
| // If the source and destination have the same number of elements, use a |
| // vector shuffle instead of insert/extracts. |
| unsigned NumResultElts = ExprVT->getNumElements(); |
| unsigned NumSourceElts = |
| cast<llvm::VectorType>(Vec->getType())->getNumElements(); |
| |
| if (NumResultElts == NumSourceElts) { |
| llvm::SmallVector<llvm::Constant*, 4> Mask; |
| for (unsigned i = 0; i != NumResultElts; ++i) { |
| unsigned InIdx = OCUVectorElementExpr::getAccessedFieldNo(i, EncFields); |
| Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx)); |
| } |
| |
| llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size()); |
| Vec = Builder.CreateShuffleVector(Vec, |
| llvm::UndefValue::get(Vec->getType()), |
| MaskV, "tmp"); |
| return RValue::get(Vec); |
| } |
| |
| // Start out with an undef of the result type. |
| llvm::Value *Result = llvm::UndefValue::get(ConvertType(ExprType)); |
| |
| // Extract/Insert each element of the result. |
| for (unsigned i = 0; i != NumResultElts; ++i) { |
| unsigned InIdx = OCUVectorElementExpr::getAccessedFieldNo(i, EncFields); |
| llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx); |
| Elt = Builder.CreateExtractElement(Vec, Elt, "tmp"); |
| |
| llvm::Value *OutIdx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); |
| Result = Builder.CreateInsertElement(Result, Elt, OutIdx, "tmp"); |
| } |
| |
| return RValue::get(Result); |
| } |
| |
| |
| |
| /// EmitStoreThroughLValue - Store the specified rvalue into the specified |
| /// lvalue, where both are guaranteed to the have the same type, and that type |
| /// is 'Ty'. |
| void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst, |
| QualType Ty) { |
| if (!Dst.isSimple()) { |
| if (Dst.isVectorElt()) { |
| // Read/modify/write the vector, inserting the new element. |
| // FIXME: Volatility. |
| llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(), "tmp"); |
| Vec = Builder.CreateInsertElement(Vec, Src.getVal(), |
| Dst.getVectorIdx(), "vecins"); |
| Builder.CreateStore(Vec, Dst.getVectorAddr()); |
| return; |
| } |
| |
| // If this is an update of elements of a vector, insert them as appropriate. |
| if (Dst.isOCUVectorElt()) |
| return EmitStoreThroughOCUComponentLValue(Src, Dst, Ty); |
| |
| assert(0 && "FIXME: Don't support store to bitfield yet"); |
| } |
| |
| llvm::Value *DstAddr = Dst.getAddress(); |
| assert(Src.isScalar() && "Can't emit an agg store with this method"); |
| // FIXME: Handle volatility etc. |
| const llvm::Type *SrcTy = Src.getVal()->getType(); |
| const llvm::Type *AddrTy = |
| cast<llvm::PointerType>(DstAddr->getType())->getElementType(); |
| |
| if (AddrTy != SrcTy) |
| DstAddr = Builder.CreateBitCast(DstAddr, llvm::PointerType::get(SrcTy), |
| "storetmp"); |
| Builder.CreateStore(Src.getVal(), DstAddr); |
| } |
| |
| void CodeGenFunction::EmitStoreThroughOCUComponentLValue(RValue Src, LValue Dst, |
| QualType Ty) { |
| // This access turns into a read/modify/write of the vector. Load the input |
| // value now. |
| llvm::Value *Vec = Builder.CreateLoad(Dst.getOCUVectorAddr(), "tmp"); |
| // FIXME: Volatility. |
| unsigned EncFields = Dst.getOCUVectorElts(); |
| |
| llvm::Value *SrcVal = Src.getVal(); |
| |
| if (const VectorType *VTy = Ty->getAsVectorType()) { |
| unsigned NumSrcElts = VTy->getNumElements(); |
| |
| // Extract/Insert each element. |
| for (unsigned i = 0; i != NumSrcElts; ++i) { |
| llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); |
| Elt = Builder.CreateExtractElement(SrcVal, Elt, "tmp"); |
| |
| unsigned Idx = OCUVectorElementExpr::getAccessedFieldNo(i, EncFields); |
| llvm::Value *OutIdx = llvm::ConstantInt::get(llvm::Type::Int32Ty, Idx); |
| Vec = Builder.CreateInsertElement(Vec, Elt, OutIdx, "tmp"); |
| } |
| } else { |
| // If the Src is a scalar (not a vector) it must be updating one element. |
| unsigned InIdx = OCUVectorElementExpr::getAccessedFieldNo(0, EncFields); |
| llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx); |
| Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp"); |
| } |
| |
| Builder.CreateStore(Vec, Dst.getOCUVectorAddr()); |
| } |
| |
| |
| LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) { |
| const Decl *D = E->getDecl(); |
| if (isa<BlockVarDecl>(D) || isa<ParmVarDecl>(D)) { |
| llvm::Value *V = LocalDeclMap[D]; |
| assert(V && "BlockVarDecl not entered in LocalDeclMap?"); |
| return LValue::MakeAddr(V); |
| } else if (isa<FunctionDecl>(D) || isa<FileVarDecl>(D)) { |
| return LValue::MakeAddr(CGM.GetAddrOfGlobalDecl(D)); |
| } |
| assert(0 && "Unimp declref"); |
| } |
| |
| LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) { |
| // __extension__ doesn't affect lvalue-ness. |
| if (E->getOpcode() == UnaryOperator::Extension) |
| return EmitLValue(E->getSubExpr()); |
| |
| assert(E->getOpcode() == UnaryOperator::Deref && |
| "'*' is the only unary operator that produces an lvalue"); |
| return LValue::MakeAddr(EmitScalarExpr(E->getSubExpr())); |
| } |
| |
| LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) { |
| assert(!E->isWide() && "FIXME: Wide strings not supported yet!"); |
| const char *StrData = E->getStrData(); |
| unsigned Len = E->getByteLength(); |
| |
| // FIXME: Can cache/reuse these within the module. |
| llvm::Constant *C=llvm::ConstantArray::get(std::string(StrData, StrData+Len)); |
| |
| // Create a global variable for this. |
| C = new llvm::GlobalVariable(C->getType(), true, |
| llvm::GlobalValue::InternalLinkage, |
| C, ".str", CurFn->getParent()); |
| llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty); |
| llvm::Constant *Zeros[] = { Zero, Zero }; |
| C = llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2); |
| return LValue::MakeAddr(C); |
| } |
| |
| LValue CodeGenFunction::EmitPreDefinedLValue(const PreDefinedExpr *E) { |
| std::string FunctionName(CurFuncDecl->getName()); |
| std::string GlobalVarName; |
| |
| switch (E->getIdentType()) { |
| default: |
| assert(0 && "unknown pre-defined ident type"); |
| case PreDefinedExpr::Func: |
| GlobalVarName = "__func__."; |
| break; |
| case PreDefinedExpr::Function: |
| GlobalVarName = "__FUNCTION__."; |
| break; |
| case PreDefinedExpr::PrettyFunction: |
| // FIXME:: Demangle C++ method names |
| GlobalVarName = "__PRETTY_FUNCTION__."; |
| break; |
| } |
| |
| GlobalVarName += CurFuncDecl->getName(); |
| |
| // FIXME: Can cache/reuse these within the module. |
| llvm::Constant *C=llvm::ConstantArray::get(FunctionName); |
| |
| // Create a global variable for this. |
| C = new llvm::GlobalVariable(C->getType(), true, |
| llvm::GlobalValue::InternalLinkage, |
| C, GlobalVarName, CurFn->getParent()); |
| llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty); |
| llvm::Constant *Zeros[] = { Zero, Zero }; |
| C = llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2); |
| return LValue::MakeAddr(C); |
| } |
| |
| LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) { |
| // The index must always be an integer, which is not an aggregate. Emit it. |
| llvm::Value *Idx = EmitScalarExpr(E->getIdx()); |
| |
| // If the base is a vector type, then we are forming a vector element lvalue |
| // with this subscript. |
| if (E->getLHS()->getType()->isVectorType()) { |
| // Emit the vector as an lvalue to get its address. |
| LValue LHS = EmitLValue(E->getLHS()); |
| assert(LHS.isSimple() && "Can only subscript lvalue vectors here!"); |
| // FIXME: This should properly sign/zero/extend or truncate Idx to i32. |
| return LValue::MakeVectorElt(LHS.getAddress(), Idx); |
| } |
| |
| // The base must be a pointer, which is not an aggregate. Emit it. |
| llvm::Value *Base = EmitScalarExpr(E->getBase()); |
| |
| // Extend or truncate the index type to 32 or 64-bits. |
| QualType IdxTy = E->getIdx()->getType(); |
| bool IdxSigned = IdxTy->isSignedIntegerType(); |
| unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); |
| if (IdxBitwidth != LLVMPointerWidth) |
| Idx = Builder.CreateIntCast(Idx, llvm::IntegerType::get(LLVMPointerWidth), |
| IdxSigned, "idxprom"); |
| |
| // We know that the pointer points to a type of the correct size, unless the |
| // size is a VLA. |
| if (!E->getType()->isConstantSizeType(getContext())) |
| assert(0 && "VLA idx not implemented"); |
| return LValue::MakeAddr(Builder.CreateGEP(Base, Idx, "arrayidx")); |
| } |
| |
| LValue CodeGenFunction:: |
| EmitOCUVectorElementExpr(const OCUVectorElementExpr *E) { |
| // Emit the base vector as an l-value. |
| LValue Base = EmitLValue(E->getBase()); |
| assert(Base.isSimple() && "Can only subscript lvalue vectors here!"); |
| |
| return LValue::MakeOCUVectorElt(Base.getAddress(), |
| E->getEncodedElementAccess()); |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // Expression Emission |
| //===--------------------------------------------------------------------===// |
| |
| |
| RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) { |
| if (const ImplicitCastExpr *IcExpr = |
| dyn_cast<const ImplicitCastExpr>(E->getCallee())) |
| if (const DeclRefExpr *DRExpr = |
| dyn_cast<const DeclRefExpr>(IcExpr->getSubExpr())) |
| if (const FunctionDecl *FDecl = |
| dyn_cast<const FunctionDecl>(DRExpr->getDecl())) |
| if (unsigned builtinID = FDecl->getIdentifier()->getBuiltinID()) |
| return EmitBuiltinExpr(builtinID, E); |
| |
| llvm::Value *Callee = EmitScalarExpr(E->getCallee()); |
| |
| // The callee type will always be a pointer to function type, get the function |
| // type. |
| QualType CalleeTy = E->getCallee()->getType(); |
| CalleeTy = cast<PointerType>(CalleeTy.getCanonicalType())->getPointeeType(); |
| |
| // Get information about the argument types. |
| FunctionTypeProto::arg_type_iterator ArgTyIt = 0, ArgTyEnd = 0; |
| |
| // Calling unprototyped functions provides no argument info. |
| if (const FunctionTypeProto *FTP = dyn_cast<FunctionTypeProto>(CalleeTy)) { |
| ArgTyIt = FTP->arg_type_begin(); |
| ArgTyEnd = FTP->arg_type_end(); |
| } |
| |
| llvm::SmallVector<llvm::Value*, 16> Args; |
| |
| // Handle struct-return functions by passing a pointer to the location that |
| // we would like to return into. |
| if (hasAggregateLLVMType(E->getType())) { |
| // Create a temporary alloca to hold the result of the call. :( |
| Args.push_back(CreateTempAlloca(ConvertType(E->getType()))); |
| // FIXME: set the stret attribute on the argument. |
| } |
| |
| for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) { |
| QualType ArgTy = E->getArg(i)->getType(); |
| |
| if (!hasAggregateLLVMType(ArgTy)) { |
| // Scalar argument is passed by-value. |
| Args.push_back(EmitScalarExpr(E->getArg(i))); |
| } else if (ArgTy->isComplexType()) { |
| // Make a temporary alloca to pass the argument. |
| llvm::Value *DestMem = CreateTempAlloca(ConvertType(ArgTy)); |
| EmitComplexExprIntoAddr(E->getArg(i), DestMem, false); |
| Args.push_back(DestMem); |
| } else { |
| llvm::Value *DestMem = CreateTempAlloca(ConvertType(ArgTy)); |
| EmitAggExpr(E->getArg(i), DestMem, false); |
| Args.push_back(DestMem); |
| } |
| } |
| |
| llvm::Value *V = Builder.CreateCall(Callee, &Args[0], &Args[0]+Args.size()); |
| if (V->getType() != llvm::Type::VoidTy) |
| V->setName("call"); |
| else if (hasAggregateLLVMType(E->getType())) |
| // Struct return. |
| return RValue::getAggregate(Args[0]); |
| |
| return RValue::get(V); |
| } |