llvm/Analysis/ObjCARCAliasAnalysis.h

0001 //===- ObjCARCAliasAnalysis.h - ObjC ARC Alias Analysis ---------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 /// \file
0009 /// This file declares a simple ARC-aware AliasAnalysis using special knowledge
0010 /// of Objective C to enhance other optimization passes which rely on the Alias
0011 /// Analysis infrastructure.
0012 ///
0013 /// WARNING: This file knows about certain library functions. It recognizes them
0014 /// by name, and hardwires knowledge of their semantics.
0015 ///
0016 /// WARNING: This file knows about how certain Objective-C library functions are
0017 /// used. Naive LLVM IR transformations which would otherwise be
0018 /// behavior-preserving may break these assumptions.
0019 ///
0020 //===----------------------------------------------------------------------===//
0021
0022 #ifndef LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H
0023 #define LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H
0024
0025 #include "llvm/Analysis/AliasAnalysis.h"
0026
0027 namespace llvm {
0028 namespace objcarc {
0029
0030 /// This is a simple alias analysis implementation that uses knowledge
0031 /// of ARC constructs to answer queries.
0032 ///
0033 /// TODO: This class could be generalized to know about other ObjC-specific
0034 /// tricks. Such as knowing that ivars in the non-fragile ABI are non-aliasing
0035 /// even though their offsets are dynamic.
0036 class ObjCARCAAResult : public AAResultBase {
0037   const DataLayout &DL;
0038
0039 public:
0040   explicit ObjCARCAAResult(const DataLayout &DL) : DL(DL) {}
0041   ObjCARCAAResult(ObjCARCAAResult &&Arg)
0042       : AAResultBase(std::move(Arg)), DL(Arg.DL) {}
0043
0044   /// Handle invalidation events from the new pass manager.
0045   ///
0046   /// By definition, this result is stateless and so remains valid.
0047   bool invalidate(Function &, const PreservedAnalyses &,
0048                   FunctionAnalysisManager::Invalidator &) {
0049     return false;
0050   }
0051
0052   AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
0053                     AAQueryInfo &AAQI, const Instruction *CtxI);
0054   ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI,
0055                                bool IgnoreLocals);
0056
0057   using AAResultBase::getMemoryEffects;
0058   MemoryEffects getMemoryEffects(const Function *F);
0059
0060   using AAResultBase::getModRefInfo;
0061   ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
0062                            AAQueryInfo &AAQI);
0063 };
0064
0065 /// Analysis pass providing a never-invalidated alias analysis result.
0066 class ObjCARCAA : public AnalysisInfoMixin<ObjCARCAA> {
0067   friend AnalysisInfoMixin<ObjCARCAA>;
0068   static AnalysisKey Key;
0069
0070 public:
0071   typedef ObjCARCAAResult Result;
0072
0073   ObjCARCAAResult run(Function &F, FunctionAnalysisManager &AM);
0074 };
0075
0076 } // namespace objcarc
0077 } // namespace llvm
0078
0079 #endif