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//===- ObjCARC.h - ObjC ARC Optimization --------------*- mode: c++ -*-----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file defines common definitions/declarations used by the ObjC ARC
/// Optimizer. ARC stands for Automatic Reference Counting and is a system for
/// managing reference counts for objects in Objective C.
///
/// 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.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_SCALAR_OBJCARC_H
#define LLVM_TRANSFORMS_SCALAR_OBJCARC_H
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/ObjCARC.h"
namespace llvm {
namespace objcarc {
/// \brief A handy option to enable/disable all ARC Optimizations.
extern bool EnableARCOpts;
/// \brief Test if the given module looks interesting to run ARC optimization
/// on.
static inline bool ModuleHasARC(const Module &M) {
return
M.getNamedValue("objc_retain") ||
M.getNamedValue("objc_release") ||
M.getNamedValue("objc_autorelease") ||
M.getNamedValue("objc_retainAutoreleasedReturnValue") ||
M.getNamedValue("objc_retainBlock") ||
M.getNamedValue("objc_autoreleaseReturnValue") ||
M.getNamedValue("objc_autoreleasePoolPush") ||
M.getNamedValue("objc_loadWeakRetained") ||
M.getNamedValue("objc_loadWeak") ||
M.getNamedValue("objc_destroyWeak") ||
M.getNamedValue("objc_storeWeak") ||
M.getNamedValue("objc_initWeak") ||
M.getNamedValue("objc_moveWeak") ||
M.getNamedValue("objc_copyWeak") ||
M.getNamedValue("objc_retainedObject") ||
M.getNamedValue("objc_unretainedObject") ||
M.getNamedValue("objc_unretainedPointer");
}
/// \enum InstructionClass
/// \brief A simple classification for instructions.
enum InstructionClass {
IC_Retain, ///< objc_retain
IC_RetainRV, ///< objc_retainAutoreleasedReturnValue
IC_RetainBlock, ///< objc_retainBlock
IC_Release, ///< objc_release
IC_Autorelease, ///< objc_autorelease
IC_AutoreleaseRV, ///< objc_autoreleaseReturnValue
IC_AutoreleasepoolPush, ///< objc_autoreleasePoolPush
IC_AutoreleasepoolPop, ///< objc_autoreleasePoolPop
IC_NoopCast, ///< objc_retainedObject, etc.
IC_FusedRetainAutorelease, ///< objc_retainAutorelease
IC_FusedRetainAutoreleaseRV, ///< objc_retainAutoreleaseReturnValue
IC_LoadWeakRetained, ///< objc_loadWeakRetained (primitive)
IC_StoreWeak, ///< objc_storeWeak (primitive)
IC_InitWeak, ///< objc_initWeak (derived)
IC_LoadWeak, ///< objc_loadWeak (derived)
IC_MoveWeak, ///< objc_moveWeak (derived)
IC_CopyWeak, ///< objc_copyWeak (derived)
IC_DestroyWeak, ///< objc_destroyWeak (derived)
IC_StoreStrong, ///< objc_storeStrong (derived)
IC_CallOrUser, ///< could call objc_release and/or "use" pointers
IC_Call, ///< could call objc_release
IC_User, ///< could "use" a pointer
IC_None ///< anything else
};
static raw_ostream &operator<<(raw_ostream &OS, const InstructionClass Class)
LLVM_ATTRIBUTE_USED;
static raw_ostream &operator<<(raw_ostream &OS, const InstructionClass Class) {
switch (Class) {
case IC_Retain:
return OS << "IC_Retain";
case IC_RetainRV:
return OS << "IC_RetainRV";
case IC_RetainBlock:
return OS << "IC_RetainBlock";
case IC_Release:
return OS << "IC_Release";
case IC_Autorelease:
return OS << "IC_Autorelease";
case IC_AutoreleaseRV:
return OS << "IC_AutoreleaseRV";
case IC_AutoreleasepoolPush:
return OS << "IC_AutoreleasepoolPush";
case IC_AutoreleasepoolPop:
return OS << "IC_AutoreleasepoolPop";
case IC_NoopCast:
return OS << "IC_NoopCast";
case IC_FusedRetainAutorelease:
return OS << "IC_FusedRetainAutorelease";
case IC_FusedRetainAutoreleaseRV:
return OS << "IC_FusedRetainAutoreleaseRV";
case IC_LoadWeakRetained:
return OS << "IC_LoadWeakRetained";
case IC_StoreWeak:
return OS << "IC_StoreWeak";
case IC_InitWeak:
return OS << "IC_InitWeak";
case IC_LoadWeak:
return OS << "IC_LoadWeak";
case IC_MoveWeak:
return OS << "IC_MoveWeak";
case IC_CopyWeak:
return OS << "IC_CopyWeak";
case IC_DestroyWeak:
return OS << "IC_DestroyWeak";
case IC_StoreStrong:
return OS << "IC_StoreStrong";
case IC_CallOrUser:
return OS << "IC_CallOrUser";
case IC_Call:
return OS << "IC_Call";
case IC_User:
return OS << "IC_User";
case IC_None:
return OS << "IC_None";
}
llvm_unreachable("Unknown instruction class!");
}
/// \brief Determine if F is one of the special known Functions. If it isn't,
/// return IC_CallOrUser.
static inline InstructionClass GetFunctionClass(const Function *F) {
Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
// No arguments.
if (AI == AE)
return StringSwitch<InstructionClass>(F->getName())
.Case("objc_autoreleasePoolPush", IC_AutoreleasepoolPush)
.Default(IC_CallOrUser);
// One argument.
const Argument *A0 = AI++;
if (AI == AE)
// Argument is a pointer.
if (PointerType *PTy = dyn_cast<PointerType>(A0->getType())) {
Type *ETy = PTy->getElementType();
// Argument is i8*.
if (ETy->isIntegerTy(8))
return StringSwitch<InstructionClass>(F->getName())
.Case("objc_retain", IC_Retain)
.Case("objc_retainAutoreleasedReturnValue", IC_RetainRV)
.Case("objc_retainBlock", IC_RetainBlock)
.Case("objc_release", IC_Release)
.Case("objc_autorelease", IC_Autorelease)
.Case("objc_autoreleaseReturnValue", IC_AutoreleaseRV)
.Case("objc_autoreleasePoolPop", IC_AutoreleasepoolPop)
.Case("objc_retainedObject", IC_NoopCast)
.Case("objc_unretainedObject", IC_NoopCast)
.Case("objc_unretainedPointer", IC_NoopCast)
.Case("objc_retain_autorelease", IC_FusedRetainAutorelease)
.Case("objc_retainAutorelease", IC_FusedRetainAutorelease)
.Case("objc_retainAutoreleaseReturnValue",IC_FusedRetainAutoreleaseRV)
.Default(IC_CallOrUser);
// Argument is i8**
if (PointerType *Pte = dyn_cast<PointerType>(ETy))
if (Pte->getElementType()->isIntegerTy(8))
return StringSwitch<InstructionClass>(F->getName())
.Case("objc_loadWeakRetained", IC_LoadWeakRetained)
.Case("objc_loadWeak", IC_LoadWeak)
.Case("objc_destroyWeak", IC_DestroyWeak)
.Default(IC_CallOrUser);
}
// Two arguments, first is i8**.
const Argument *A1 = AI++;
if (AI == AE)
if (PointerType *PTy = dyn_cast<PointerType>(A0->getType()))
if (PointerType *Pte = dyn_cast<PointerType>(PTy->getElementType()))
if (Pte->getElementType()->isIntegerTy(8))
if (PointerType *PTy1 = dyn_cast<PointerType>(A1->getType())) {
Type *ETy1 = PTy1->getElementType();
// Second argument is i8*
if (ETy1->isIntegerTy(8))
return StringSwitch<InstructionClass>(F->getName())
.Case("objc_storeWeak", IC_StoreWeak)
.Case("objc_initWeak", IC_InitWeak)
.Case("objc_storeStrong", IC_StoreStrong)
.Default(IC_CallOrUser);
// Second argument is i8**.
if (PointerType *Pte1 = dyn_cast<PointerType>(ETy1))
if (Pte1->getElementType()->isIntegerTy(8))
return StringSwitch<InstructionClass>(F->getName())
.Case("objc_moveWeak", IC_MoveWeak)
.Case("objc_copyWeak", IC_CopyWeak)
.Default(IC_CallOrUser);
}
// Anything else.
return IC_CallOrUser;
}
/// \brief Determine which objc runtime call instruction class V belongs to.
///
/// This is similar to GetInstructionClass except that it only detects objc
/// runtime calls. This allows it to be faster.
///
static inline InstructionClass GetBasicInstructionClass(const Value *V) {
if (const CallInst *CI = dyn_cast<CallInst>(V)) {
if (const Function *F = CI->getCalledFunction())
return GetFunctionClass(F);
// Otherwise, be conservative.
return IC_CallOrUser;
}
// Otherwise, be conservative.
return isa<InvokeInst>(V) ? IC_CallOrUser : IC_User;
}
} // end namespace objcarc
} // end namespace llvm
#endif // LLVM_TRANSFORMS_SCALAR_OBJCARC_H
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