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//===- ARCInstKind.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 several utility functions used by various ARC
/// optimizations which are IMHO too big to be in a header file.
///
/// 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 "llvm/Analysis/ObjCARCInstKind.h"
#include "llvm/Analysis/ObjCARCAnalysisUtils.h"
#include "llvm/IR/Intrinsics.h"
using namespace llvm;
using namespace llvm::objcarc;
raw_ostream &llvm::objcarc::operator<<(raw_ostream &OS,
const ARCInstKind Class) {
switch (Class) {
case ARCInstKind::Retain:
return OS << "ARCInstKind::Retain";
case ARCInstKind::RetainRV:
return OS << "ARCInstKind::RetainRV";
case ARCInstKind::UnsafeClaimRV:
return OS << "ARCInstKind::UnsafeClaimRV";
case ARCInstKind::RetainBlock:
return OS << "ARCInstKind::RetainBlock";
case ARCInstKind::Release:
return OS << "ARCInstKind::Release";
case ARCInstKind::Autorelease:
return OS << "ARCInstKind::Autorelease";
case ARCInstKind::AutoreleaseRV:
return OS << "ARCInstKind::AutoreleaseRV";
case ARCInstKind::AutoreleasepoolPush:
return OS << "ARCInstKind::AutoreleasepoolPush";
case ARCInstKind::AutoreleasepoolPop:
return OS << "ARCInstKind::AutoreleasepoolPop";
case ARCInstKind::NoopCast:
return OS << "ARCInstKind::NoopCast";
case ARCInstKind::FusedRetainAutorelease:
return OS << "ARCInstKind::FusedRetainAutorelease";
case ARCInstKind::FusedRetainAutoreleaseRV:
return OS << "ARCInstKind::FusedRetainAutoreleaseRV";
case ARCInstKind::LoadWeakRetained:
return OS << "ARCInstKind::LoadWeakRetained";
case ARCInstKind::StoreWeak:
return OS << "ARCInstKind::StoreWeak";
case ARCInstKind::InitWeak:
return OS << "ARCInstKind::InitWeak";
case ARCInstKind::LoadWeak:
return OS << "ARCInstKind::LoadWeak";
case ARCInstKind::MoveWeak:
return OS << "ARCInstKind::MoveWeak";
case ARCInstKind::CopyWeak:
return OS << "ARCInstKind::CopyWeak";
case ARCInstKind::DestroyWeak:
return OS << "ARCInstKind::DestroyWeak";
case ARCInstKind::StoreStrong:
return OS << "ARCInstKind::StoreStrong";
case ARCInstKind::CallOrUser:
return OS << "ARCInstKind::CallOrUser";
case ARCInstKind::Call:
return OS << "ARCInstKind::Call";
case ARCInstKind::User:
return OS << "ARCInstKind::User";
case ARCInstKind::IntrinsicUser:
return OS << "ARCInstKind::IntrinsicUser";
case ARCInstKind::None:
return OS << "ARCInstKind::None";
}
llvm_unreachable("Unknown instruction class!");
}
ARCInstKind llvm::objcarc::GetFunctionClass(const Function *F) {
Intrinsic::ID ID = F->getIntrinsicID();
switch (ID) {
default:
return ARCInstKind::CallOrUser;
case Intrinsic::objc_autorelease:
return ARCInstKind::Autorelease;
case Intrinsic::objc_autoreleasePoolPop:
return ARCInstKind::AutoreleasepoolPop;
case Intrinsic::objc_autoreleasePoolPush:
return ARCInstKind::AutoreleasepoolPush;
case Intrinsic::objc_autoreleaseReturnValue:
return ARCInstKind::AutoreleaseRV;
case Intrinsic::objc_copyWeak:
return ARCInstKind::CopyWeak;
case Intrinsic::objc_destroyWeak:
return ARCInstKind::DestroyWeak;
case Intrinsic::objc_initWeak:
return ARCInstKind::InitWeak;
case Intrinsic::objc_loadWeak:
return ARCInstKind::LoadWeak;
case Intrinsic::objc_loadWeakRetained:
return ARCInstKind::LoadWeakRetained;
case Intrinsic::objc_moveWeak:
return ARCInstKind::MoveWeak;
case Intrinsic::objc_release:
return ARCInstKind::Release;
case Intrinsic::objc_retain:
return ARCInstKind::Retain;
case Intrinsic::objc_retainAutorelease:
return ARCInstKind::FusedRetainAutorelease;
case Intrinsic::objc_retainAutoreleaseReturnValue:
return ARCInstKind::FusedRetainAutoreleaseRV;
case Intrinsic::objc_retainAutoreleasedReturnValue:
return ARCInstKind::RetainRV;
case Intrinsic::objc_retainBlock:
return ARCInstKind::RetainBlock;
case Intrinsic::objc_storeStrong:
return ARCInstKind::StoreStrong;
case Intrinsic::objc_storeWeak:
return ARCInstKind::StoreWeak;
case Intrinsic::objc_clang_arc_use:
return ARCInstKind::IntrinsicUser;
case Intrinsic::objc_unsafeClaimAutoreleasedReturnValue:
return ARCInstKind::UnsafeClaimRV;
case Intrinsic::objc_retainedObject:
return ARCInstKind::NoopCast;
case Intrinsic::objc_unretainedObject:
return ARCInstKind::NoopCast;
case Intrinsic::objc_unretainedPointer:
return ARCInstKind::NoopCast;
case Intrinsic::objc_retain_autorelease:
return ARCInstKind::FusedRetainAutorelease;
case Intrinsic::objc_sync_enter:
return ARCInstKind::User;
case Intrinsic::objc_sync_exit:
return ARCInstKind::User;
case Intrinsic::objc_clang_arc_noop_use:
case Intrinsic::objc_arc_annotation_topdown_bbstart:
case Intrinsic::objc_arc_annotation_topdown_bbend:
case Intrinsic::objc_arc_annotation_bottomup_bbstart:
case Intrinsic::objc_arc_annotation_bottomup_bbend:
// Ignore annotation calls. This is important to stop the
// optimizer from treating annotations as uses which would
// make the state of the pointers they are attempting to
// elucidate to be incorrect.
return ARCInstKind::None;
}
}
// A list of intrinsics that we know do not use objc pointers or decrement
// ref counts.
static bool isInertIntrinsic(unsigned ID) {
// TODO: Make this into a covered switch.
switch (ID) {
case Intrinsic::returnaddress:
case Intrinsic::addressofreturnaddress:
case Intrinsic::frameaddress:
case Intrinsic::stacksave:
case Intrinsic::stackrestore:
case Intrinsic::vastart:
case Intrinsic::vacopy:
case Intrinsic::vaend:
case Intrinsic::objectsize:
case Intrinsic::prefetch:
case Intrinsic::stackprotector:
case Intrinsic::eh_return_i32:
case Intrinsic::eh_return_i64:
case Intrinsic::eh_typeid_for:
case Intrinsic::eh_dwarf_cfa:
case Intrinsic::eh_sjlj_lsda:
case Intrinsic::eh_sjlj_functioncontext:
case Intrinsic::init_trampoline:
case Intrinsic::adjust_trampoline:
case Intrinsic::lifetime_start:
case Intrinsic::lifetime_end:
case Intrinsic::invariant_start:
case Intrinsic::invariant_end:
// Don't let dbg info affect our results.
case Intrinsic::dbg_declare:
case Intrinsic::dbg_value:
case Intrinsic::dbg_label:
// Short cut: Some intrinsics obviously don't use ObjC pointers.
return true;
default:
return false;
}
}
// A list of intrinsics that we know do not use objc pointers or decrement
// ref counts.
static bool isUseOnlyIntrinsic(unsigned ID) {
// We are conservative and even though intrinsics are unlikely to touch
// reference counts, we white list them for safety.
//
// TODO: Expand this into a covered switch. There is a lot more here.
switch (ID) {
case Intrinsic::memcpy:
case Intrinsic::memmove:
case Intrinsic::memset:
return true;
default:
return false;
}
}
/// Determine what kind of construct V is.
ARCInstKind llvm::objcarc::GetARCInstKind(const Value *V) {
if (const Instruction *I = dyn_cast<Instruction>(V)) {
// Any instruction other than bitcast and gep with a pointer operand have a
// use of an objc pointer. Bitcasts, GEPs, Selects, PHIs transfer a pointer
// to a subsequent use, rather than using it themselves, in this sense.
// As a short cut, several other opcodes are known to have no pointer
// operands of interest. And ret is never followed by a release, so it's
// not interesting to examine.
switch (I->getOpcode()) {
case Instruction::Call: {
const CallInst *CI = cast<CallInst>(I);
// See if we have a function that we know something about.
if (const Function *F = CI->getCalledFunction()) {
ARCInstKind Class = GetFunctionClass(F);
if (Class != ARCInstKind::CallOrUser)
return Class;
Intrinsic::ID ID = F->getIntrinsicID();
if (isInertIntrinsic(ID))
return ARCInstKind::None;
if (isUseOnlyIntrinsic(ID))
return ARCInstKind::User;
}
// Otherwise, be conservative.
return GetCallSiteClass(*CI);
}
case Instruction::Invoke:
// Otherwise, be conservative.
return GetCallSiteClass(cast<InvokeInst>(*I));
case Instruction::BitCast:
case Instruction::GetElementPtr:
case Instruction::Select:
case Instruction::PHI:
case Instruction::Ret:
case Instruction::Br:
case Instruction::Switch:
case Instruction::IndirectBr:
case Instruction::Alloca:
case Instruction::VAArg:
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
case Instruction::SDiv:
case Instruction::UDiv:
case Instruction::FDiv:
case Instruction::SRem:
case Instruction::URem:
case Instruction::FRem:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
case Instruction::SExt:
case Instruction::ZExt:
case Instruction::Trunc:
case Instruction::IntToPtr:
case Instruction::FCmp:
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::InsertElement:
case Instruction::ExtractElement:
case Instruction::ShuffleVector:
case Instruction::ExtractValue:
break;
case Instruction::ICmp:
// Comparing a pointer with null, or any other constant, isn't an
// interesting use, because we don't care what the pointer points to, or
// about the values of any other dynamic reference-counted pointers.
if (IsPotentialRetainableObjPtr(I->getOperand(1)))
return ARCInstKind::User;
break;
default:
// For anything else, check all the operands.
// Note that this includes both operands of a Store: while the first
// operand isn't actually being dereferenced, it is being stored to
// memory where we can no longer track who might read it and dereference
// it, so we have to consider it potentially used.
for (const Use &U : I->operands())
if (IsPotentialRetainableObjPtr(U))
return ARCInstKind::User;
}
}
// Otherwise, it's totally inert for ARC purposes.
return ARCInstKind::None;
}
/// Test if the given class is a kind of user.
bool llvm::objcarc::IsUser(ARCInstKind Class) {
switch (Class) {
case ARCInstKind::User:
case ARCInstKind::CallOrUser:
case ARCInstKind::IntrinsicUser:
return true;
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::RetainBlock:
case ARCInstKind::Release:
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::NoopCast:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::Call:
case ARCInstKind::None:
case ARCInstKind::UnsafeClaimRV:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test if the given class is objc_retain or equivalent.
bool llvm::objcarc::IsRetain(ARCInstKind Class) {
switch (Class) {
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
return true;
// I believe we treat retain block as not a retain since it can copy its
// block.
case ARCInstKind::RetainBlock:
case ARCInstKind::Release:
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::NoopCast:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::User:
case ARCInstKind::None:
case ARCInstKind::UnsafeClaimRV:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test if the given class is objc_autorelease or equivalent.
bool llvm::objcarc::IsAutorelease(ARCInstKind Class) {
switch (Class) {
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
return true;
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::UnsafeClaimRV:
case ARCInstKind::RetainBlock:
case ARCInstKind::Release:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::NoopCast:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::User:
case ARCInstKind::None:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test if the given class represents instructions which return their
/// argument verbatim.
bool llvm::objcarc::IsForwarding(ARCInstKind Class) {
switch (Class) {
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::UnsafeClaimRV:
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::NoopCast:
return true;
case ARCInstKind::RetainBlock:
case ARCInstKind::Release:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::User:
case ARCInstKind::None:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test if the given class represents instructions which do nothing if
/// passed a null pointer.
bool llvm::objcarc::IsNoopOnNull(ARCInstKind Class) {
switch (Class) {
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::UnsafeClaimRV:
case ARCInstKind::Release:
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::RetainBlock:
return true;
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::User:
case ARCInstKind::None:
case ARCInstKind::NoopCast:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test if the given class represents instructions which do nothing if
/// passed a global variable.
bool llvm::objcarc::IsNoopOnGlobal(ARCInstKind Class) {
switch (Class) {
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::UnsafeClaimRV:
case ARCInstKind::Release:
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::RetainBlock:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
return true;
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::User:
case ARCInstKind::None:
case ARCInstKind::NoopCast:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test if the given class represents instructions which are always safe
/// to mark with the "tail" keyword.
bool llvm::objcarc::IsAlwaysTail(ARCInstKind Class) {
// ARCInstKind::RetainBlock may be given a stack argument.
switch (Class) {
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::UnsafeClaimRV:
case ARCInstKind::AutoreleaseRV:
return true;
case ARCInstKind::Release:
case ARCInstKind::Autorelease:
case ARCInstKind::RetainBlock:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::User:
case ARCInstKind::None:
case ARCInstKind::NoopCast:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test if the given class represents instructions which are never safe
/// to mark with the "tail" keyword.
bool llvm::objcarc::IsNeverTail(ARCInstKind Class) {
/// It is never safe to tail call objc_autorelease since by tail calling
/// objc_autorelease: fast autoreleasing causing our object to be potentially
/// reclaimed from the autorelease pool which violates the semantics of
/// __autoreleasing types in ARC.
switch (Class) {
case ARCInstKind::Autorelease:
return true;
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::UnsafeClaimRV:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::Release:
case ARCInstKind::RetainBlock:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::User:
case ARCInstKind::None:
case ARCInstKind::NoopCast:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test if the given class represents instructions which are always safe
/// to mark with the nounwind attribute.
bool llvm::objcarc::IsNoThrow(ARCInstKind Class) {
// objc_retainBlock is not nounwind because it calls user copy constructors
// which could theoretically throw.
switch (Class) {
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::UnsafeClaimRV:
case ARCInstKind::Release:
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
return true;
case ARCInstKind::RetainBlock:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::User:
case ARCInstKind::None:
case ARCInstKind::NoopCast:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
/// Test whether the given instruction can autorelease any pointer or cause an
/// autoreleasepool pop.
///
/// This means that it *could* interrupt the RV optimization.
bool llvm::objcarc::CanInterruptRV(ARCInstKind Class) {
switch (Class) {
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
return true;
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::UnsafeClaimRV:
case ARCInstKind::Release:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::RetainBlock:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::User:
case ARCInstKind::None:
case ARCInstKind::NoopCast:
return false;
}
llvm_unreachable("covered switch isn't covered?");
}
bool llvm::objcarc::CanDecrementRefCount(ARCInstKind Kind) {
switch (Kind) {
case ARCInstKind::Retain:
case ARCInstKind::RetainRV:
case ARCInstKind::Autorelease:
case ARCInstKind::AutoreleaseRV:
case ARCInstKind::NoopCast:
case ARCInstKind::FusedRetainAutorelease:
case ARCInstKind::FusedRetainAutoreleaseRV:
case ARCInstKind::IntrinsicUser:
case ARCInstKind::User:
case ARCInstKind::None:
return false;
// The cases below are conservative.
// RetainBlock can result in user defined copy constructors being called
// implying releases may occur.
case ARCInstKind::RetainBlock:
case ARCInstKind::Release:
case ARCInstKind::AutoreleasepoolPush:
case ARCInstKind::AutoreleasepoolPop:
case ARCInstKind::LoadWeakRetained:
case ARCInstKind::StoreWeak:
case ARCInstKind::InitWeak:
case ARCInstKind::LoadWeak:
case ARCInstKind::MoveWeak:
case ARCInstKind::CopyWeak:
case ARCInstKind::DestroyWeak:
case ARCInstKind::StoreStrong:
case ARCInstKind::CallOrUser:
case ARCInstKind::Call:
case ARCInstKind::UnsafeClaimRV:
return true;
}
llvm_unreachable("covered switch isn't covered?");
}