forked from OSchip/llvm-project
349 lines
12 KiB
C++
349 lines
12 KiB
C++
//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code to emit Aggregate Expr nodes as LLVM code.
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//
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//===----------------------------------------------------------------------===//
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#include "CodeGenFunction.h"
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#include "CodeGenModule.h"
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#include "clang/AST/AST.h"
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#include "llvm/Constants.h"
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#include "llvm/Function.h"
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#include "llvm/GlobalVariable.h"
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#include "llvm/Support/Compiler.h"
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using namespace clang;
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using namespace CodeGen;
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//===----------------------------------------------------------------------===//
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// Aggregate Expression Emitter
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//===----------------------------------------------------------------------===//
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namespace {
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class VISIBILITY_HIDDEN AggExprEmitter : public StmtVisitor<AggExprEmitter> {
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CodeGenFunction &CGF;
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llvm::LLVMFoldingBuilder &Builder;
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llvm::Value *DestPtr;
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bool VolatileDest;
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public:
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AggExprEmitter(CodeGenFunction &cgf, llvm::Value *destPtr, bool volatileDest)
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: CGF(cgf), Builder(CGF.Builder),
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DestPtr(destPtr), VolatileDest(volatileDest) {
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}
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//===--------------------------------------------------------------------===//
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// Utilities
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//===--------------------------------------------------------------------===//
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/// EmitAggLoadOfLValue - Given an expression with aggregate type that
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/// represents a value lvalue, this method emits the address of the lvalue,
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/// then loads the result into DestPtr.
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void EmitAggLoadOfLValue(const Expr *E);
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void EmitAggregateCopy(llvm::Value *DestPtr, llvm::Value *SrcPtr,
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QualType EltTy);
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//===--------------------------------------------------------------------===//
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// Visitor Methods
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//===--------------------------------------------------------------------===//
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void VisitStmt(Stmt *S) {
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CGF.WarnUnsupported(S, "aggregate expression");
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}
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void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
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// l-values.
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void VisitDeclRefExpr(DeclRefExpr *DRE) { EmitAggLoadOfLValue(DRE); }
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void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
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void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
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void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
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void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
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EmitAggLoadOfLValue(E);
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}
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// Operators.
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// case Expr::UnaryOperatorClass:
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// case Expr::CastExprClass:
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void VisitImplicitCastExpr(ImplicitCastExpr *E);
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void VisitCallExpr(const CallExpr *E);
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void VisitStmtExpr(const StmtExpr *E);
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void VisitBinaryOperator(const BinaryOperator *BO);
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void VisitBinAssign(const BinaryOperator *E);
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void VisitOverloadExpr(const OverloadExpr *E);
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void VisitConditionalOperator(const ConditionalOperator *CO);
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void VisitInitListExpr(InitListExpr *E);
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// case Expr::ChooseExprClass:
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private:
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llvm::Constant *GetConstantInit(InitListExpr *E,
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const llvm::ArrayType *AType);
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void EmitNonConstInit(Expr *E, llvm::Value *Dest, const llvm::Type *DestType);
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};
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} // end anonymous namespace.
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//===----------------------------------------------------------------------===//
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// Utilities
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//===----------------------------------------------------------------------===//
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void AggExprEmitter::EmitAggregateCopy(llvm::Value *DestPtr,
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llvm::Value *SrcPtr, QualType Ty) {
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assert(!Ty->isComplexType() && "Shouldn't happen for complex");
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// Aggregate assignment turns into llvm.memcpy.
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const llvm::Type *BP = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
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if (DestPtr->getType() != BP)
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DestPtr = Builder.CreateBitCast(DestPtr, BP, "tmp");
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if (SrcPtr->getType() != BP)
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SrcPtr = Builder.CreateBitCast(SrcPtr, BP, "tmp");
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// Get size and alignment info for this aggregate.
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std::pair<uint64_t, unsigned> TypeInfo =
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CGF.getContext().getTypeInfo(Ty, SourceLocation());
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// FIXME: Handle variable sized types.
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const llvm::Type *IntPtr = llvm::IntegerType::get(CGF.LLVMPointerWidth);
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llvm::Value *MemCpyOps[4] = {
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DestPtr, SrcPtr,
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// TypeInfo.first describes size in bits.
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llvm::ConstantInt::get(IntPtr, TypeInfo.first/8),
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llvm::ConstantInt::get(llvm::Type::Int32Ty, TypeInfo.second)
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};
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Builder.CreateCall(CGF.CGM.getMemCpyFn(), MemCpyOps, MemCpyOps+4);
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}
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/// EmitAggLoadOfLValue - Given an expression with aggregate type that
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/// represents a value lvalue, this method emits the address of the lvalue,
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/// then loads the result into DestPtr.
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void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
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LValue LV = CGF.EmitLValue(E);
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assert(LV.isSimple() && "Can't have aggregate bitfield, vector, etc");
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llvm::Value *SrcPtr = LV.getAddress();
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// If the result is ignored, don't copy from the value.
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if (DestPtr == 0)
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// FIXME: If the source is volatile, we must read from it.
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return;
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EmitAggregateCopy(DestPtr, SrcPtr, E->getType());
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}
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//===----------------------------------------------------------------------===//
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// Visitor Methods
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//===----------------------------------------------------------------------===//
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void AggExprEmitter::VisitImplicitCastExpr(ImplicitCastExpr *E)
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{
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QualType STy = E->getSubExpr()->getType().getCanonicalType();
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QualType Ty = E->getType().getCanonicalType();
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assert(CGF.getContext().typesAreCompatible(
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STy.getUnqualifiedType(), Ty.getUnqualifiedType())
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&& "Implicit cast types must be compatible");
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Visit(E->getSubExpr());
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}
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void AggExprEmitter::VisitCallExpr(const CallExpr *E)
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{
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RValue RV = CGF.EmitCallExpr(E);
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assert(RV.isAggregate() && "Return value must be aggregate value!");
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// If the result is ignored, don't copy from the value.
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if (DestPtr == 0)
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// FIXME: If the source is volatile, we must read from it.
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return;
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EmitAggregateCopy(DestPtr, RV.getAggregateAddr(), E->getType());
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}
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void AggExprEmitter::VisitOverloadExpr(const OverloadExpr *E)
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{
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RValue RV = CGF.EmitCallExpr(E->getFn(), E->arg_begin(),
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E->getNumArgs(CGF.getContext()));
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assert(RV.isAggregate() && "Return value must be aggregate value!");
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// If the result is ignored, don't copy from the value.
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if (DestPtr == 0)
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// FIXME: If the source is volatile, we must read from it.
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return;
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EmitAggregateCopy(DestPtr, RV.getAggregateAddr(), E->getType());
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}
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void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
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CGF.EmitCompoundStmt(*E->getSubStmt(), true, DestPtr, VolatileDest);
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}
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void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
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CGF.WarnUnsupported(E, "aggregate binary expression");
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}
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void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
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// For an assignment to work, the value on the right has
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// to be compatible with the value on the left.
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assert(CGF.getContext().typesAreCompatible(
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E->getLHS()->getType().getUnqualifiedType(),
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E->getRHS()->getType().getUnqualifiedType())
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&& "Invalid assignment");
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LValue LHS = CGF.EmitLValue(E->getLHS());
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// Codegen the RHS so that it stores directly into the LHS.
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CGF.EmitAggExpr(E->getRHS(), LHS.getAddress(), false /*FIXME: VOLATILE LHS*/);
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if (DestPtr == 0)
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return;
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// If the result of the assignment is used, copy the RHS there also.
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EmitAggregateCopy(DestPtr, LHS.getAddress(), E->getType());
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}
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void AggExprEmitter::VisitConditionalOperator(const ConditionalOperator *E) {
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llvm::BasicBlock *LHSBlock = new llvm::BasicBlock("cond.?");
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llvm::BasicBlock *RHSBlock = new llvm::BasicBlock("cond.:");
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llvm::BasicBlock *ContBlock = new llvm::BasicBlock("cond.cont");
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llvm::Value *Cond = CGF.EvaluateExprAsBool(E->getCond());
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Builder.CreateCondBr(Cond, LHSBlock, RHSBlock);
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CGF.EmitBlock(LHSBlock);
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// Handle the GNU extension for missing LHS.
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assert(E->getLHS() && "Must have LHS for aggregate value");
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Visit(E->getLHS());
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Builder.CreateBr(ContBlock);
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LHSBlock = Builder.GetInsertBlock();
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CGF.EmitBlock(RHSBlock);
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Visit(E->getRHS());
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Builder.CreateBr(ContBlock);
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RHSBlock = Builder.GetInsertBlock();
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CGF.EmitBlock(ContBlock);
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}
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llvm::Constant *AggExprEmitter::GetConstantInit(InitListExpr *E,
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const llvm::ArrayType *AType) {
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std::vector<llvm::Constant*> ArrayElts;
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unsigned NumInitElements = E->getNumInits();
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const llvm::Type *ElementType = AType->getElementType();
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unsigned i;
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for (i = 0; i != NumInitElements; ++i) {
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if (InitListExpr *InitList = dyn_cast<InitListExpr>(E->getInit(i))) {
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assert(isa<llvm::ArrayType>(ElementType) && "Invalid initilizer");
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llvm::Constant *C =
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GetConstantInit(InitList, cast<llvm::ArrayType>(ElementType));
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if (!C) return NULL;
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ArrayElts.push_back(C);
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} else if (llvm::Constant *C =
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dyn_cast<llvm::Constant>(CGF.EmitScalarExpr(E->getInit(i))))
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ArrayElts.push_back(C);
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else
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return NULL;
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}
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// Remaining default initializers
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unsigned NumArrayElements = AType->getNumElements();
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for (/*Do not initialize i*/; i < NumArrayElements; ++i)
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ArrayElts.push_back(llvm::Constant::getNullValue(ElementType));
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return llvm::ConstantArray::get(AType, ArrayElts);
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}
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void AggExprEmitter::EmitNonConstInit(Expr *E, llvm::Value *DestPtr,
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const llvm::Type *DestType) {
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if (const llvm::ArrayType *AType = dyn_cast<llvm::ArrayType>(DestType)) {
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unsigned NumInitElements = 0;
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InitListExpr *InitList = NULL;
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if (E) {
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InitList = cast<InitListExpr>(E);
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NumInitElements = InitList->getNumInits();
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}
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llvm::Value *Idxs[] = {
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llvm::Constant::getNullValue(llvm::Type::Int32Ty),
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NULL
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};
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llvm::Value *NextVal = NULL;
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unsigned i;
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for (i = 0; i != NumInitElements; ++i) {
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Idxs[1] = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
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NextVal = Builder.CreateGEP(DestPtr, Idxs, Idxs + 2,".array");
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EmitNonConstInit(InitList->getInit(i), NextVal, AType->getElementType());
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}
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// Emit remaining default initializers
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unsigned NumArrayElements = AType->getNumElements();
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for (/*Do not initialize i*/; i < NumArrayElements; ++i) {
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Idxs[1] = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
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NextVal = Builder.CreateGEP(DestPtr, Idxs, Idxs + 2,".array");
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EmitNonConstInit(NULL, NextVal, AType->getElementType());
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}
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} else {
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llvm::Value *V;
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if (E)
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V = CGF.EmitScalarExpr(E);
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else
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V = llvm::Constant::getNullValue(DestType);
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Builder.CreateStore(V, DestPtr);
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}
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}
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void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
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if (!E->getType()->isArrayType()) {
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CGF.WarnUnsupported(E, "aggregate init-list expression");
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return;
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}
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const llvm::PointerType *APType = cast<llvm::PointerType>(DestPtr->getType());
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const llvm::ArrayType *AType =
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cast<llvm::ArrayType>(APType->getElementType());
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llvm::Constant *V = GetConstantInit(E, AType);
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if (V) {
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// Create global value to hold this array.
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V = new llvm::GlobalVariable(V->getType(), true,
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llvm::GlobalValue::InternalLinkage,
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V, ".array",
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&CGF.CGM.getModule());
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EmitAggregateCopy(DestPtr, V , E->getType());
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return;
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} else
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EmitNonConstInit(E, DestPtr, AType);
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}
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//===----------------------------------------------------------------------===//
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// Entry Points into this File
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//===----------------------------------------------------------------------===//
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/// EmitAggExpr - Emit the computation of the specified expression of
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/// aggregate type. The result is computed into DestPtr. Note that if
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/// DestPtr is null, the value of the aggregate expression is not needed.
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void CodeGenFunction::EmitAggExpr(const Expr *E, llvm::Value *DestPtr,
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bool VolatileDest) {
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assert(E && hasAggregateLLVMType(E->getType()) &&
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"Invalid aggregate expression to emit");
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AggExprEmitter(*this, DestPtr, VolatileDest).Visit(const_cast<Expr*>(E));
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}
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