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ObjCARCAliasAnalysis.h
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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 
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<ObjCARCAAResult> {
39 
40  const DataLayout &DL;
41 
42 public:
43  explicit ObjCARCAAResult(const DataLayout &DL) : AAResultBase(), DL(DL) {}
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.
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 
62 
65  AAQueryInfo &AAQI);
66 };
67 
68 /// Analysis pass providing a never-invalidated alias analysis result.
69 class ObjCARCAA : public AnalysisInfoMixin<ObjCARCAA> {
71  static AnalysisKey Key;
72 
73 public:
75 
77 };
78 
79 /// Legacy wrapper pass to provide the ObjCARCAAResult object.
81  std::unique_ptr<ObjCARCAAResult> Result;
82 
83 public:
84  static char ID;
85 
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
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:110
bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI, bool OrLocal)
This class represents lattice values for constants.
Definition: AllocatorList.h:23
ObjCARCAAResult(ObjCARCAAResult &&Arg)
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:65
This class stores info we want to provide to or retain within an alias query.
FunctionModRefBehavior getModRefBehavior(const CallBase *Call)
Base class for all callable instructions (InvokeInst and CallInst) Holds everything related to callin...
Definition: InstrTypes.h:1014
F(f)
could call objc_release
Definition: BitVector.h:937
AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB, AAQueryInfo &AAQI)
A CRTP-driven "mixin" base class to help implement the function alias analysis results concept...
Key
PAL metadata keys.
FunctionModRefBehavior
Summary of how a function affects memory in the program.
FunctionModRefBehavior getModRefBehavior(const Function *F)
AliasResult
The possible results of an alias query.
Definition: AliasAnalysis.h:78
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:153
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:382
Represent the analysis usage information of a pass.
bool invalidate(Function &, const PreservedAnalyses &, FunctionAnalysisManager::Invalidator &)
Handle invalidation events from the new pass manager.
amdgpu Simplify well known AMD library false FunctionCallee Value * Arg
ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc, AAQueryInfo &AAQI)
Representation for a specific memory location.
ImmutablePass class - This class is used to provide information that does not need to be run...
Definition: Pass.h:255
const ObjCARCAAResult & getResult() const
This is a simple alias analysis implementation that uses knowledge of ARC constructs to answer querie...
API to communicate dependencies between analyses during invalidation.
Definition: PassManager.h:641
ObjCARCAAResult(const DataLayout &DL)
Legacy wrapper pass to provide the ObjCARCAAResult object.
ModRefInfo
Flags indicating whether a memory access modifies or references memory.
A container for analyses that lazily runs them and caches their results.
Analysis pass providing a never-invalidated alias analysis result.
ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc, AAQueryInfo &AAQI)
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:70