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1//===- ObjCARC.h - ObjC ARC Optimization --------------*- C++ -*-----------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8/// \file9/// This file defines common definitions/declarations used by the ObjC ARC10/// Optimizer. ARC stands for Automatic Reference Counting and is a system for11/// managing reference counts for objects in Objective C.12///13/// WARNING: This file knows about certain library functions. It recognizes them14/// by name, and hardwires knowledge of their semantics.15///16/// WARNING: This file knows about how certain Objective-C library functions are17/// used. Naive LLVM IR transformations which would otherwise be18/// behavior-preserving may break these assumptions.19///20//===----------------------------------------------------------------------===//21 22#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARC_H23#define LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARC_H24 25#include "ARCRuntimeEntryPoints.h"26#include "llvm/Analysis/ObjCARCAnalysisUtils.h"27#include "llvm/Analysis/ObjCARCUtil.h"28#include "llvm/IR/EHPersonalities.h"29#include "llvm/Transforms/Utils/Local.h"30 31namespace llvm {32namespace objcarc {33 34/// Erase the given instruction.35///36/// Many ObjC calls return their argument verbatim,37/// so if it's such a call and the return value has users, replace them with the38/// argument value.39///40static inline void EraseInstruction(Instruction *CI) {41 Value *OldArg = cast<CallInst>(CI)->getArgOperand(0);42 43 bool Unused = CI->use_empty();44 45 if (!Unused) {46 // Replace the return value with the argument.47 assert((IsForwarding(GetBasicARCInstKind(CI)) ||48 (IsNoopOnNull(GetBasicARCInstKind(CI)) &&49 IsNullOrUndef(OldArg->stripPointerCasts()))) &&50 "Can't delete non-forwarding instruction with users!");51 CI->replaceAllUsesWith(OldArg);52 }53 54 CI->eraseFromParent();55 56 if (Unused)57 RecursivelyDeleteTriviallyDeadInstructions(OldArg);58}59 60/// If Inst is a ReturnRV and its operand is a call or invoke, return the61/// operand. Otherwise return null.62static inline const Instruction *getreturnRVOperand(const Instruction &Inst,63 ARCInstKind Class) {64 if (Class != ARCInstKind::RetainRV)65 return nullptr;66 67 const auto *Opnd = Inst.getOperand(0)->stripPointerCasts();68 if (const auto *C = dyn_cast<CallInst>(Opnd))69 return C;70 return dyn_cast<InvokeInst>(Opnd);71}72 73/// Return the list of PHI nodes that are equivalent to PN.74template<class PHINodeTy, class VectorTy>75void getEquivalentPHIs(PHINodeTy &PN, VectorTy &PHIList) {76 auto *BB = PN.getParent();77 for (auto &P : BB->phis()) {78 if (&P == &PN) // Do not add PN to the list.79 continue;80 unsigned I = 0, E = PN.getNumIncomingValues();81 for (; I < E; ++I) {82 auto *BB = PN.getIncomingBlock(I);83 auto *PNOpnd = PN.getIncomingValue(I)->stripPointerCasts();84 auto *POpnd = P.getIncomingValueForBlock(BB)->stripPointerCasts();85 if (PNOpnd != POpnd)86 break;87 }88 if (I == E)89 PHIList.push_back(&P);90 }91}92 93static inline MDString *getRVInstMarker(Module &M) {94 const char *MarkerKey = getRVMarkerModuleFlagStr();95 return dyn_cast_or_null<MDString>(M.getModuleFlag(MarkerKey));96}97 98/// Create a call instruction with the correct funclet token. This should be99/// called instead of calling CallInst::Create directly unless the call is100/// going to be removed from the IR before WinEHPrepare.101CallInst *createCallInstWithColors(102 FunctionCallee Func, ArrayRef<Value *> Args, const Twine &NameStr,103 BasicBlock::iterator InsertBefore,104 const DenseMap<BasicBlock *, ColorVector> &BlockColors);105 106class BundledRetainClaimRVs {107public:108 BundledRetainClaimRVs(ARCRuntimeEntryPoints &EP, bool ContractPass,109 bool UseClaimRV)110 : EP(EP), ContractPass(ContractPass), UseClaimRV(UseClaimRV) {}111 ~BundledRetainClaimRVs();112 113 /// Insert a retainRV/claimRV call to the normal destination blocks of invokes114 /// with operand bundle "clang.arc.attachedcall". If the edge to the normal115 /// destination block is a critical edge, split it.116 std::pair<bool, bool> insertAfterInvokes(Function &F, DominatorTree *DT);117 118 /// Insert a retainRV/claimRV call.119 CallInst *insertRVCall(BasicBlock::iterator InsertPt,120 CallBase *AnnotatedCall);121 122 /// Insert a retainRV/claimRV call with colors.123 CallInst *insertRVCallWithColors(124 BasicBlock::iterator InsertPt, CallBase *AnnotatedCall,125 const DenseMap<BasicBlock *, ColorVector> &BlockColors);126 127 /// See if an instruction is a bundled retainRV/claimRV call.128 bool contains(const Instruction *I) const {129 if (auto *CI = dyn_cast<CallInst>(I))130 return RVCalls.count(CI);131 return false;132 }133 134 /// Remove a retainRV/claimRV call entirely.135 void eraseInst(CallInst *CI) {136 auto It = RVCalls.find(CI);137 if (It != RVCalls.end()) {138 // Remove call to @llvm.objc.clang.arc.noop.use.139 for (User *U : It->second->users())140 if (auto *CI = dyn_cast<CallInst>(U))141 if (CI->getIntrinsicID() == Intrinsic::objc_clang_arc_noop_use) {142 CI->eraseFromParent();143 break;144 }145 146 auto *NewCall = CallBase::removeOperandBundle(147 It->second, LLVMContext::OB_clang_arc_attachedcall,148 It->second->getIterator());149 NewCall->copyMetadata(*It->second);150 It->second->replaceAllUsesWith(NewCall);151 It->second->eraseFromParent();152 RVCalls.erase(It);153 }154 EraseInstruction(CI);155 }156 157private:158 /// A map of inserted retainRV/claimRV calls to annotated calls/invokes.159 DenseMap<CallInst *, CallBase *> RVCalls;160 161 ARCRuntimeEntryPoints &EP;162 bool ContractPass;163 bool UseClaimRV;164};165 166} // end namespace objcarc167} // end namespace llvm168 169#endif170