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
27namespace llvm {
28namespace objcarc {
29
30/// This is a simple alias analysis implementation that uses knowledge
31/// of ARC constructs to answer queries.
32///
33/// TODO: This class could be generalized to know about other ObjC-specific
34/// tricks. Such as knowing that ivars in the non-fragile ABI are non-aliasing
35/// even though their offsets are dynamic.
36class ObjCARCAAResult : public AAResultBase {
37 const DataLayout &DL;
38
39public:
40 explicit ObjCARCAAResult(const DataLayout &DL) : DL(DL) {}
41 ObjCARCAAResult(ObjCARCAAResult &&Arg)
42 : AAResultBase(std::move(Arg)), DL(Arg.DL) {}
43
44 /// Handle invalidation events from the new pass manager.
45 ///
46 /// By definition, this result is stateless and so remains valid.
47 bool invalidate(Function &, const PreservedAnalyses &,
48 FunctionAnalysisManager::Invalidator &) {
49 return false;
50 }
51
52 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
53 AAQueryInfo &AAQI, const Instruction *CtxI);
54 ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI,
55 bool IgnoreLocals);
56
57 using AAResultBase::getMemoryEffects;
58 MemoryEffects getMemoryEffects(const Function *F);
59
60 using AAResultBase::getModRefInfo;
61 ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
62 AAQueryInfo &AAQI);
63};
64
65/// Analysis pass providing a never-invalidated alias analysis result.
66class ObjCARCAA : public AnalysisInfoMixin<ObjCARCAA> {
67 friend AnalysisInfoMixin<ObjCARCAA>;
68 static AnalysisKey Key;
69
70public:
71 typedef ObjCARCAAResult Result;
72
73 ObjCARCAAResult run(Function &F, FunctionAnalysisManager &AM);
74};
75
76} // namespace objcarc
77} // namespace llvm
78
79#endif
80