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//===--- 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/AST/AST.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
using namespace llvm;
using namespace clang;
using namespace CodeGen;
CodeGenFunction::CodeGenFunction(CodeGenModule &cgm)
: CGM(cgm), Target(CGM.getContext().Target) {}
llvm::BasicBlock *CodeGenFunction::getBasicBlockForLabel(const LabelStmt *S) {
BasicBlock *&BB = LabelMap[S];
if (BB) return BB;
// Create, but don't insert, the new block.
return BB = new BasicBlock(S->getName());
}
/// ConvertType - Convert the specified type to its LLVM form.
const llvm::Type *CodeGenFunction::ConvertType(QualType T, SourceLocation Loc) {
// FIXME: Cache these, move the CodeGenModule, expand, etc.
const clang::Type &Ty = *T.getCanonicalType();
switch (Ty.getTypeClass()) {
case Type::Builtin: {
switch (cast<BuiltinType>(Ty).getKind()) {
case BuiltinType::Void:
// LLVM void type can only be used as the result of a function call. Just
// map to the same as char.
case BuiltinType::Char:
case BuiltinType::SChar:
case BuiltinType::UChar:
return IntegerType::get(Target.getCharWidth(Loc));
case BuiltinType::Bool:
return IntegerType::get(Target.getBoolWidth(Loc));
case BuiltinType::Short:
case BuiltinType::UShort:
return IntegerType::get(Target.getShortWidth(Loc));
case BuiltinType::Int:
case BuiltinType::UInt:
return IntegerType::get(Target.getIntWidth(Loc));
case BuiltinType::Long:
case BuiltinType::ULong:
return IntegerType::get(Target.getLongWidth(Loc));
case BuiltinType::LongLong:
case BuiltinType::ULongLong:
return IntegerType::get(Target.getLongLongWidth(Loc));
case BuiltinType::Float: return llvm::Type::FloatTy;
case BuiltinType::Double: return llvm::Type::DoubleTy;
case BuiltinType::LongDouble:
case BuiltinType::FloatComplex:
case BuiltinType::DoubleComplex:
case BuiltinType::LongDoubleComplex:
;
}
break;
}
case Type::Pointer:
case Type::Reference:
case Type::Array:
break;
case Type::FunctionNoProto:
case Type::FunctionProto: {
const FunctionType &FP = cast<FunctionType>(Ty);
const llvm::Type *ResultType;
if (FP.getResultType()->isVoidType())
ResultType = llvm::Type::VoidTy; // Result of function uses llvm void.
else
ResultType = ConvertType(FP.getResultType(), Loc);
// FIXME: Convert argument types.
return llvm::FunctionType::get(ResultType,
std::vector<const llvm::Type*>(),
false,
0);
}
case Type::TypeName:
case Type::Tagged:
break;
}
// FIXME: implement.
return OpaqueType::get();
}
void CodeGenFunction::GenerateCode(const FunctionDecl *FD) {
const llvm::Type *Ty = ConvertType(FD->getType(), FD->getLocation());
CurFn = new Function(cast<llvm::FunctionType>(Ty),
Function::ExternalLinkage,
FD->getName(), &CGM.getModule());
BasicBlock *EntryBB = new BasicBlock("entry", CurFn);
// TODO: Walk the decls, creating allocas etc.
Builder.SetInsertPoint(EntryBB);
EmitStmt(FD->getBody());
}
//===----------------------------------------------------------------------===//
// Statement Emission
//===----------------------------------------------------------------------===//
void CodeGenFunction::EmitStmt(const Stmt *S) {
assert(S && "Null statement?");
switch (S->getStmtClass()) {
default:
printf("Unimplemented stmt!\n");
S->dump();
break;
case Stmt::NullStmtClass: break;
case Stmt::CompoundStmtClass: EmitCompoundStmt(cast<CompoundStmt>(*S)); break;
case Stmt::LabelStmtClass: EmitLabelStmt(cast<LabelStmt>(*S)); break;
case Stmt::GotoStmtClass: EmitGotoStmt(cast<GotoStmt>(*S)); break;
}
}
void CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S) {
// FIXME: handle vla's etc.
for (CompoundStmt::const_body_iterator I = S.body_begin(), E = S.body_end();
I != E; ++I)
EmitStmt(*I);
}
void CodeGenFunction::EmitBlock(BasicBlock *BB) {
// Emit a branch from this block to the next one if this was a real block. If
// this was just a fall-through block after a terminator, don't emit it.
if (!Builder.GetInsertBlock()->empty() ||
Builder.GetInsertBlock()->getValueName()) {
Builder.CreateBr(BB);
} else {
// TODO: cache and reuse these.
Builder.GetInsertBlock()->eraseFromParent();
}
CurFn->getBasicBlockList().push_back(BB);
Builder.SetInsertPoint(BB);
}
void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
llvm::BasicBlock *NextBB = getBasicBlockForLabel(&S);
EmitBlock(NextBB);
}
void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
Builder.CreateBr(getBasicBlockForLabel(S.getLabel()));
Builder.SetInsertPoint(new BasicBlock("", CurFn));
}
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