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 | |
28 | namespace llvm { |
29 | namespace 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. |
37 | class ObjCARCAAResult : public AAResultBase { |
38 | const DataLayout &DL; |
39 | |
40 | public: |
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. |
67 | class ObjCARCAA : public AnalysisInfoMixin<ObjCARCAA> { |
68 | friend AnalysisInfoMixin<ObjCARCAA>; |
69 | static AnalysisKey Key; |
70 | |
71 | public: |
72 | typedef ObjCARCAAResult Result; |
73 | |
74 | ObjCARCAAResult run(Function &F, FunctionAnalysisManager &AM); |
75 | }; |
76 | |
77 | } // namespace objcarc |
78 | } // namespace llvm |
79 | |
80 | #endif |
81 | |