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//===------- CGObjCGNU.cpp - Emit LLVM Code from ASTs for a Module --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This provides Objective-C code generation targetting the GNU runtime.
//
//===----------------------------------------------------------------------===//
#include "CGObjCRuntime.h"
#include "llvm/Module.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/LLVMBuilder.h"
#include "llvm/ADT/SmallVector.h"
using namespace clang::CodeGen;
using namespace clang;
CGObjCRuntime::~CGObjCRuntime() {}
namespace {
class CGObjCGNU : public CGObjCRuntime {
private:
llvm::Module &TheModule;
public:
CGObjCGNU(llvm::Module &M) : TheModule(M) {};
virtual llvm::Value *generateMessageSend(llvm::LLVMFoldingBuilder &Builder,
const llvm::Type *ReturnTy,
llvm::Value *Receiver,
llvm::Constant *Selector,
llvm::Value** ArgV,
unsigned ArgC);
};
} // end anonymous namespace
// Generate code for a message send expression on the GNU runtime.
// BIG FAT WARNING: Much of this code will need factoring out later.
// FIXME: This currently only handles id returns. Other return types
// need some explicit casting.
llvm::Value *CGObjCGNU::generateMessageSend(llvm::LLVMFoldingBuilder &Builder,
const llvm::Type *ReturnTy,
llvm::Value *Receiver,
llvm::Constant *Selector,
llvm::Value** ArgV,
unsigned ArgC) {
// Get the selector Type.
const llvm::Type *PtrToInt8Ty =
llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
std::vector<const llvm::Type*> Str2(2, PtrToInt8Ty);
const llvm::Type *SelStructTy = llvm::StructType::get(Str2);
const llvm::Type *SelTy = llvm::PointerType::getUnqual(SelStructTy);
// Look up the selector.
// If we haven't got the selector lookup function, look it up now.
// TODO: Factor this out and use it to implement @selector() too.
llvm::Constant *SelFunction =
TheModule.getOrInsertFunction("sel_get_uid", SelTy, PtrToInt8Ty, NULL);
// FIXME: Selectors should be statically cached, not looked up on every call.
// TODO: Pull this out into the caller.
llvm::Constant *Idx0 = llvm::ConstantInt::get(llvm::Type::Int32Ty, 0);
llvm::Constant *Ops[] = {Idx0, Idx0};
llvm::Value *SelStr = llvm::ConstantExpr::getGetElementPtr(Selector, Ops, 2);
llvm::Value *cmd = Builder.CreateCall(SelFunction, &SelStr, &SelStr+1);
// Look up the method implementation.
std::vector<const llvm::Type*> impArgTypes;
impArgTypes.push_back(Receiver->getType());
impArgTypes.push_back(SelTy);
// Avoid an explicit cast on the IMP by getting a version that has the right
// return type.
llvm::FunctionType *impType = llvm::FunctionType::get(ReturnTy, impArgTypes,
true);
llvm::Constant *lookupFunction =
TheModule.getOrInsertFunction("objc_msg_lookup",
llvm::PointerType::get(impType, 0),
Receiver->getType(), SelTy, NULL);
llvm::SmallVector<llvm::Value*, 16> lookupArgs;
lookupArgs.push_back(Receiver);
lookupArgs.push_back(cmd);
llvm::Value *imp = Builder.CreateCall(lookupFunction,
lookupArgs.begin(), lookupArgs.end());
// Call the method.
lookupArgs.insert(lookupArgs.end(), ArgV, ArgV+ArgC);
return Builder.CreateCall(imp, lookupArgs.begin(), lookupArgs.end());
}
CGObjCRuntime * clang::CodeGen::CreateObjCRuntime(llvm::Module &M) {
return new CGObjCGNU(M);
}
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