1 //===- ObjCARCAliasAnalysis.h - ObjC ARC Alias Analysis ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 /// This file declares a simple ARC-aware AliasAnalysis using special knowledge
11 /// of Objective C to enhance other optimization passes which rely on the Alias
12 /// Analysis infrastructure.
14 /// WARNING: This file knows about certain library functions. It recognizes them
15 /// by name, and hardwires knowledge of their semantics.
17 /// WARNING: This file knows about how certain Objective-C library functions are
18 /// used. Naive LLVM IR transformations which would otherwise be
19 /// behavior-preserving may break these assumptions.
21 //===----------------------------------------------------------------------===//
23 #ifndef LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H
24 #define LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H
26 #include "llvm/Analysis/AliasAnalysis.h"
27 #include "llvm/Pass.h"
32 /// \brief This is a simple alias analysis implementation that uses knowledge
33 /// of ARC constructs to answer queries.
35 /// TODO: This class could be generalized to know about other ObjC-specific
36 /// tricks. Such as knowing that ivars in the non-fragile ABI are non-aliasing
37 /// even though their offsets are dynamic.
38 class ObjCARCAAResult : public AAResultBase<ObjCARCAAResult> {
39 friend AAResultBase<ObjCARCAAResult>;
44 explicit ObjCARCAAResult(const DataLayout &DL) : AAResultBase(), DL(DL) {}
45 ObjCARCAAResult(ObjCARCAAResult &&Arg)
46 : AAResultBase(std::move(Arg)), DL(Arg.DL) {}
48 /// Handle invalidation events from the new pass manager.
50 /// By definition, this result is stateless and so remains valid.
51 bool invalidate(Function &, const PreservedAnalyses &,
52 FunctionAnalysisManager::Invalidator &) {
56 AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB);
57 bool pointsToConstantMemory(const MemoryLocation &Loc, bool OrLocal);
59 using AAResultBase::getModRefBehavior;
60 FunctionModRefBehavior getModRefBehavior(const Function *F);
62 using AAResultBase::getModRefInfo;
63 ModRefInfo getModRefInfo(ImmutableCallSite CS, const MemoryLocation &Loc);
66 /// Analysis pass providing a never-invalidated alias analysis result.
67 class ObjCARCAA : public AnalysisInfoMixin<ObjCARCAA> {
68 friend AnalysisInfoMixin<ObjCARCAA>;
69 static AnalysisKey Key;
72 typedef ObjCARCAAResult Result;
74 ObjCARCAAResult run(Function &F, FunctionAnalysisManager &AM);
77 /// Legacy wrapper pass to provide the ObjCARCAAResult object.
78 class ObjCARCAAWrapperPass : public ImmutablePass {
79 std::unique_ptr<ObjCARCAAResult> Result;
84 ObjCARCAAWrapperPass();
86 ObjCARCAAResult &getResult() { return *Result; }
87 const ObjCARCAAResult &getResult() const { return *Result; }
89 bool doInitialization(Module &M) override;
90 bool doFinalization(Module &M) override;
91 void getAnalysisUsage(AnalysisUsage &AU) const override;
94 } // namespace objcarc