| //===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===// |
| // |
| // 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 coordinates the per-function state used while generating code. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CodeGenFunction.h" |
| #include "CodeGenModule.h" |
| #include "clang/Basic/TargetInfo.h" |
| #include "clang/Basic/Diagnostic.h" |
| #include "clang/AST/AST.h" |
| #include "llvm/Constants.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/Function.h" |
| #include "llvm/Analysis/Verifier.h" |
| #include "llvm/Support/CFG.h" |
| using namespace clang; |
| using namespace CodeGen; |
| |
| CodeGenFunction::CodeGenFunction(CodeGenModule &cgm) |
| : CGM(cgm), Target(CGM.getContext().Target), SwitchInsn(NULL), |
| CaseRangeBlock(NULL) {} |
| |
| ASTContext &CodeGenFunction::getContext() const { |
| return CGM.getContext(); |
| } |
| |
| |
| llvm::BasicBlock *CodeGenFunction::getBasicBlockForLabel(const LabelStmt *S) { |
| llvm::BasicBlock *&BB = LabelMap[S]; |
| if (BB) return BB; |
| |
| // Create, but don't insert, the new block. |
| return BB = new llvm::BasicBlock(S->getName()); |
| } |
| |
| |
| const llvm::Type *CodeGenFunction::ConvertType(QualType T) { |
| return CGM.getTypes().ConvertType(T); |
| } |
| |
| bool CodeGenFunction::hasAggregateLLVMType(QualType T) { |
| return !T->isRealType() && !T->isPointerType() && !T->isReferenceType() && |
| !T->isVoidType() && !T->isVectorType() && !T->isFunctionType(); |
| } |
| |
| |
| void CodeGenFunction::GenerateCode(const FunctionDecl *FD) { |
| LLVMIntTy = ConvertType(getContext().IntTy); |
| LLVMPointerWidth = static_cast<unsigned>( |
| getContext().getTypeSize(getContext().getPointerType(getContext().VoidTy), |
| SourceLocation())); |
| |
| CurFuncDecl = FD; |
| llvm::Constant *CurFnC = CGM.GetAddrOfGlobalDecl(FD); |
| if (!(CurFn = dyn_cast<llvm::Function>(CurFnC))) { |
| // If CurFnC is not a constant, it must be a bitcast of another function. |
| llvm::ConstantExpr *CurFnCE = cast<llvm::ConstantExpr>(CurFnC); |
| assert(CurFnCE->getOpcode() == llvm::Instruction::BitCast && |
| "Unexpected name collision"); |
| llvm::Function *OtherFunc = cast<llvm::Function>(CurFnCE->getOperand(0)); |
| |
| // This happens if there is a prototype for a function (e.g. "int f()") and |
| // then a definition of a different type (e.g. "int f(int x)"). Start by |
| // making a new function of the correct type, RAUW, then steal the name. |
| const llvm::PointerType *PTy = cast<llvm::PointerType>(CurFnC->getType()); |
| const llvm::FunctionType *FTy = |
| cast<llvm::FunctionType>(PTy->getElementType()); |
| CurFn = new llvm::Function(FTy, llvm::Function::ExternalLinkage, "", |
| &CGM.getModule()); |
| CurFn->takeName(OtherFunc); |
| |
| // Replace uses of OtherFunc with the Function we will endow with a body. |
| llvm::Constant *NewPtrForOldDecl = |
| llvm::ConstantExpr::getBitCast(CurFn, OtherFunc->getType()); |
| OtherFunc->replaceAllUsesWith(NewPtrForOldDecl); |
| |
| // Make sure the GlobalDecl map for FD is up-to-date. |
| CGM.ChangeGlobalDeclMap(FD, CurFn); |
| |
| // FIXME: Update the globaldeclmap for the previous decl of this name. We |
| // really want a way to walk all of these, but we don't have it yet. This |
| // is incredibly slow! |
| CGM.ReplaceMapValuesWith(OtherFunc, NewPtrForOldDecl); |
| |
| // Ok, delete the old function now, which is dead. |
| assert(OtherFunc->isDeclaration() && "Shouldn't replace non-declaration"); |
| OtherFunc->eraseFromParent(); |
| } |
| |
| assert(CurFn->isDeclaration() && "Function already has body?"); |
| |
| // TODO: Set up linkage and many other things. Note, this is a simple |
| // approximation of what we really want. |
| if (FD->getStorageClass() == FunctionDecl::Static) |
| CurFn->setLinkage(llvm::Function::InternalLinkage); |
| else if (FD->isInline()) |
| CurFn->setLinkage(llvm::Function::WeakLinkage); |
| |
| llvm::BasicBlock *EntryBB = new llvm::BasicBlock("entry", CurFn); |
| |
| Builder.SetInsertPoint(EntryBB); |
| |
| // Create a marker to make it easy to insert allocas into the entryblock |
| // later. |
| llvm::Value *Undef = llvm::UndefValue::get(llvm::Type::Int32Ty); |
| AllocaInsertPt = Builder.CreateBitCast(Undef,llvm::Type::Int32Ty, "allocapt"); |
| |
| // Emit allocs for param decls. Give the LLVM Argument nodes names. |
| llvm::Function::arg_iterator AI = CurFn->arg_begin(); |
| |
| // Name the struct return argument. |
| if (hasAggregateLLVMType(FD->getResultType())) { |
| AI->setName("agg.result"); |
| ++AI; |
| } |
| |
| for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i, ++AI) { |
| assert(AI != CurFn->arg_end() && "Argument mismatch!"); |
| EmitParmDecl(*FD->getParamDecl(i), AI); |
| } |
| |
| // Emit the function body. |
| EmitStmt(FD->getBody()); |
| |
| // Emit a return for code that falls off the end. If insert point |
| // is a dummy block with no predecessors then remove the block itself. |
| llvm::BasicBlock *BB = Builder.GetInsertBlock(); |
| if (isDummyBlock(BB)) |
| BB->eraseFromParent(); |
| else { |
| // FIXME: if this is C++ main, this should return 0. |
| if (CurFn->getReturnType() == llvm::Type::VoidTy) |
| Builder.CreateRetVoid(); |
| else |
| Builder.CreateRet(llvm::UndefValue::get(CurFn->getReturnType())); |
| } |
| assert(BreakContinueStack.empty() && |
| "mismatched push/pop in break/continue stack!"); |
| |
| // Verify that the function is well formed. |
| assert(!verifyFunction(*CurFn)); |
| } |
| |
| /// isDummyBlock - Return true if BB is an empty basic block |
| /// with no predecessors. |
| bool CodeGenFunction::isDummyBlock(const llvm::BasicBlock *BB) { |
| if (BB->empty() && pred_begin(BB) == pred_end(BB)) |
| return true; |
| return false; |
| } |
| |
| /// StartBlock - Start new block named N. If insert block is a dummy block |
| /// then reuse it. |
| void CodeGenFunction::StartBlock(const char *N) { |
| llvm::BasicBlock *BB = Builder.GetInsertBlock(); |
| if (!isDummyBlock(BB)) |
| EmitBlock(new llvm::BasicBlock(N)); |
| else |
| BB->setName(N); |
| } |
| |
| /// getCGRecordLayout - Return record layout info. |
| const CGRecordLayout *CodeGenFunction::getCGRecordLayout(CodeGenTypes &CGT, |
| QualType RTy) { |
| assert (isa<RecordType>(RTy) |
| && "Unexpected type. RecordType expected here."); |
| |
| const llvm::Type *Ty = ConvertType(RTy); |
| assert (Ty && "Unable to find llvm::Type"); |
| |
| return CGT.getCGRecordLayout(Ty); |
| } |
| |
| /// WarnUnsupported - Print out a warning that codegen doesn't support the |
| /// specified stmt yet. |
| void CodeGenFunction::WarnUnsupported(const Stmt *S, const char *Type) { |
| unsigned DiagID = CGM.getDiags().getCustomDiagID(Diagnostic::Warning, |
| "cannot codegen this %0 yet"); |
| SourceRange Range = S->getSourceRange(); |
| std::string Msg = Type; |
| CGM.getDiags().Report(S->getLocStart(), DiagID, &Msg, 1, &Range, 1); |
| } |
| |