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 {
38 const DataLayout &DL;
39
40public:
41 explicit ObjCARCAAResult(const DataLayout &DL) : DL(DL) {}
42 ObjCARCAAResult(ObjCARCAAResult &&Arg)
43 : AAResultBase(std::move(Arg)), DL(Arg.DL) {}
44
45 /// Handle invalidation events from the new pass manager.
46 ///
47 /// By definition, this result is stateless and so remains valid.
48 bool invalidate(Function &, const PreservedAnalyses &,
49 FunctionAnalysisManager::Invalidator &) {
50 return false;
51 }
52
53 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
54 AAQueryInfo &AAQI, const Instruction *CtxI);
55 ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI,
56 bool IgnoreLocals);
57
58 using AAResultBase::getMemoryEffects;
59 MemoryEffects getMemoryEffects(const Function *F);
60
61 using AAResultBase::getModRefInfo;
62 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
63 AAQueryInfo &AAQI);
64};
65
66/// Analysis pass providing a never-invalidated alias analysis result.
67class ObjCARCAA : public AnalysisInfoMixin<ObjCARCAA> {
68 friend AnalysisInfoMixin<ObjCARCAA>;
69 static AnalysisKey Key;
70
71public:
72 typedef ObjCARCAAResult Result;
73
74 ObjCARCAAResult run(Function &F, FunctionAnalysisManager &AM);
75};
76
77} // namespace objcarc
78} // namespace llvm
79
80#endif
81

source code of llvm/include/llvm/Analysis/ObjCARCAliasAnalysis.h