mirror of
https://github.com/RPCS3/llvm.git
synced 2025-05-22 21:35:57 +00:00
6b547686c5
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
130 lines
3.9 KiB
C++
130 lines
3.9 KiB
C++
//===- ObjCARCExpand.cpp - ObjC ARC Optimization --------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
/// \file
|
|
/// This file defines ObjC ARC optimizations. ARC stands for Automatic
|
|
/// Reference Counting and is a system for managing reference counts for objects
|
|
/// in Objective C.
|
|
///
|
|
/// This specific file deals with early optimizations which perform certain
|
|
/// cleanup operations.
|
|
///
|
|
/// WARNING: This file knows about certain library functions. It recognizes them
|
|
/// by name, and hardwires knowledge of their semantics.
|
|
///
|
|
/// WARNING: This file knows about how certain Objective-C library functions are
|
|
/// used. Naive LLVM IR transformations which would otherwise be
|
|
/// behavior-preserving may break these assumptions.
|
|
///
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "ObjCARC.h"
|
|
#include "llvm/IR/Function.h"
|
|
#include "llvm/IR/InstIterator.h"
|
|
#include "llvm/IR/Instruction.h"
|
|
#include "llvm/IR/Instructions.h"
|
|
#include "llvm/IR/Value.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/PassAnalysisSupport.h"
|
|
#include "llvm/PassRegistry.h"
|
|
#include "llvm/PassSupport.h"
|
|
#include "llvm/Support/Casting.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
|
|
#define DEBUG_TYPE "objc-arc-expand"
|
|
|
|
namespace llvm {
|
|
class Module;
|
|
}
|
|
|
|
using namespace llvm;
|
|
using namespace llvm::objcarc;
|
|
|
|
namespace {
|
|
/// Early ARC transformations.
|
|
class ObjCARCExpand : public FunctionPass {
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override;
|
|
bool doInitialization(Module &M) override;
|
|
bool runOnFunction(Function &F) override;
|
|
|
|
/// A flag indicating whether this optimization pass should run.
|
|
bool Run;
|
|
|
|
public:
|
|
static char ID;
|
|
ObjCARCExpand() : FunctionPass(ID) {
|
|
initializeObjCARCExpandPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
};
|
|
}
|
|
|
|
char ObjCARCExpand::ID = 0;
|
|
INITIALIZE_PASS(ObjCARCExpand,
|
|
"objc-arc-expand", "ObjC ARC expansion", false, false)
|
|
|
|
Pass *llvm::createObjCARCExpandPass() {
|
|
return new ObjCARCExpand();
|
|
}
|
|
|
|
void ObjCARCExpand::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesCFG();
|
|
}
|
|
|
|
bool ObjCARCExpand::doInitialization(Module &M) {
|
|
Run = ModuleHasARC(M);
|
|
return false;
|
|
}
|
|
|
|
bool ObjCARCExpand::runOnFunction(Function &F) {
|
|
if (!EnableARCOpts)
|
|
return false;
|
|
|
|
// If nothing in the Module uses ARC, don't do anything.
|
|
if (!Run)
|
|
return false;
|
|
|
|
bool Changed = false;
|
|
|
|
LLVM_DEBUG(dbgs() << "ObjCARCExpand: Visiting Function: " << F.getName()
|
|
<< "\n");
|
|
|
|
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ++I) {
|
|
Instruction *Inst = &*I;
|
|
|
|
LLVM_DEBUG(dbgs() << "ObjCARCExpand: Visiting: " << *Inst << "\n");
|
|
|
|
switch (GetBasicARCInstKind(Inst)) {
|
|
case ARCInstKind::Retain:
|
|
case ARCInstKind::RetainRV:
|
|
case ARCInstKind::Autorelease:
|
|
case ARCInstKind::AutoreleaseRV:
|
|
case ARCInstKind::FusedRetainAutorelease:
|
|
case ARCInstKind::FusedRetainAutoreleaseRV: {
|
|
// These calls return their argument verbatim, as a low-level
|
|
// optimization. However, this makes high-level optimizations
|
|
// harder. Undo any uses of this optimization that the front-end
|
|
// emitted here. We'll redo them in the contract pass.
|
|
Changed = true;
|
|
Value *Value = cast<CallInst>(Inst)->getArgOperand(0);
|
|
LLVM_DEBUG(dbgs() << "ObjCARCExpand: Old = " << *Inst
|
|
<< "\n"
|
|
" New = "
|
|
<< *Value << "\n");
|
|
Inst->replaceAllUsesWith(Value);
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
LLVM_DEBUG(dbgs() << "ObjCARCExpand: Finished List.\n\n");
|
|
|
|
return Changed;
|
|
}
|