1 //===- ProvenanceAnalysis.h - ObjC ARC Optimization ---*- 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 //===----------------------------------------------------------------------===//
11 /// This file declares a special form of Alias Analysis called ``Provenance
12 /// Analysis''. The word ``provenance'' refers to the history of the ownership
13 /// of an object. Thus ``Provenance Analysis'' is an analysis which attempts to
14 /// use various techniques to determine if locally
16 /// WARNING: This file knows about certain library functions. It recognizes them
17 /// by name, and hardwires knowledge of their semantics.
19 /// WARNING: This file knows about how certain Objective-C library functions are
20 /// used. Naive LLVM IR transformations which would otherwise be
21 /// behavior-preserving may break these assumptions.
23 //===----------------------------------------------------------------------===//
25 #ifndef LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H
26 #define LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H
28 #include "llvm/ADT/DenseMap.h"
29 #include "llvm/Analysis/AliasAnalysis.h"
41 /// \brief This is similar to BasicAliasAnalysis, and it uses many of the same
42 /// techniques, except it uses special ObjC-specific reasoning about pointer
45 /// In this context ``Provenance'' is defined as the history of an object's
46 /// ownership. Thus ``Provenance Analysis'' is defined by using the notion of
47 /// an ``independent provenance source'' of a pointer to determine whether or
48 /// not two pointers have the same provenance source and thus could
49 /// potentially be related.
50 class ProvenanceAnalysis {
53 typedef std::pair<const Value *, const Value *> ValuePairTy;
54 typedef DenseMap<ValuePairTy, bool> CachedResultsTy;
55 CachedResultsTy CachedResults;
57 bool relatedCheck(const Value *A, const Value *B, const DataLayout &DL);
58 bool relatedSelect(const SelectInst *A, const Value *B);
59 bool relatedPHI(const PHINode *A, const Value *B);
61 void operator=(const ProvenanceAnalysis &) = delete;
62 ProvenanceAnalysis(const ProvenanceAnalysis &) = delete;
65 ProvenanceAnalysis() {}
67 void setAA(AliasAnalysis *aa) { AA = aa; }
69 AliasAnalysis *getAA() const { return AA; }
71 bool related(const Value *A, const Value *B, const DataLayout &DL);
74 CachedResults.clear();
78 } // end namespace objcarc
79 } // end namespace llvm