1//===- ObjCARCAliasAnalysis.h - ObjC ARC Alias Analysis ---------*- 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-exception 6// 7//===----------------------------------------------------------------------===// 8/// \file 9/// This file declares a simple ARC-aware AliasAnalysis using special knowledge 10/// of Objective C to enhance other optimization passes which rely on the Alias 11/// Analysis infrastructure. 12/// 13/// WARNING: This file knows about certain library functions. It recognizes them 14/// by name, and hardwires knowledge of their semantics. 15/// 16/// WARNING: This file knows about how certain Objective-C library functions are 17/// used. Naive LLVM IR transformations which would otherwise be 18/// behavior-preserving may break these assumptions. 19/// 20//===----------------------------------------------------------------------===// 21 22#ifndef LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H 23#define LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H 24 25#include "llvm/Analysis/AliasAnalysis.h" 26#include "llvm/Pass.h" 27 28namespace llvm { 29namespace objcarc { 30 31/// This is a simple alias analysis implementation that uses knowledge 32/// of ARC constructs to answer queries. 33/// 34/// TODO: This class could be generalized to know about other ObjC-specific 35/// tricks. Such as knowing that ivars in the non-fragile ABI are non-aliasing 36/// even though their offsets are dynamic. 37class ObjCARCAAResult : public AAResultBase<ObjCARCAAResult> { 38 friend AAResultBase<ObjCARCAAResult>; 39 40 const DataLayout &DL; 41 42public: 43 explicit ObjCARCAAResult(const DataLayout &DL) : AAResultBase(), DL(DL) {} 44 ObjCARCAAResult(ObjCARCAAResult &&Arg) 45 : AAResultBase(std::move(Arg)), DL(Arg.DL) {} 46 47 /// Handle invalidation events from the new pass manager. 48 /// 49 /// By definition, this result is stateless and so remains valid. 50 bool invalidate(Function &, const PreservedAnalyses &, 51 FunctionAnalysisManager::Invalidator &) { 52 return false; 53 } 54 55 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB, 56 AAQueryInfo &AAQI); 57 bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI, 58 bool OrLocal); 59 60 using AAResultBase::getModRefBehavior; 61 FunctionModRefBehavior getModRefBehavior(const Function *F); 62 63 using AAResultBase::getModRefInfo; 64 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc, 65 AAQueryInfo &AAQI); 66}; 67 68/// Analysis pass providing a never-invalidated alias analysis result. 69class ObjCARCAA : public AnalysisInfoMixin<ObjCARCAA> { 70 friend AnalysisInfoMixin<ObjCARCAA>; 71 static AnalysisKey Key; 72 73public: 74 typedef ObjCARCAAResult Result; 75 76 ObjCARCAAResult run(Function &F, FunctionAnalysisManager &AM); 77}; 78 79/// Legacy wrapper pass to provide the ObjCARCAAResult object. 80class ObjCARCAAWrapperPass : public ImmutablePass { 81 std::unique_ptr<ObjCARCAAResult> Result; 82 83public: 84 static char ID; 85 86 ObjCARCAAWrapperPass(); 87 88 ObjCARCAAResult &getResult() { return *Result; } 89 const ObjCARCAAResult &getResult() const { return *Result; } 90 91 bool doInitialization(Module &M) override; 92 bool doFinalization(Module &M) override; 93 void getAnalysisUsage(AnalysisUsage &AU) const override; 94}; 95 96} // namespace objcarc 97} // namespace llvm 98 99#endif 100