LLVM  6.0.0svn
ProvenanceAnalysis.h
Go to the documentation of this file.
1 //===- ProvenanceAnalysis.h - ObjC ARC Optimization ---*- C++ -*-----------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 /// \file
10 ///
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
15 ///
16 /// WARNING: This file knows about certain library functions. It recognizes them
17 /// by name, and hardwires knowledge of their semantics.
18 ///
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.
22 ///
23 //===----------------------------------------------------------------------===//
24 
25 #ifndef LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H
26 #define LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H
27 
28 #include "llvm/ADT/DenseMap.h"
30 
31 namespace llvm {
32  class Value;
33  class DataLayout;
34  class PHINode;
35  class SelectInst;
36 }
37 
38 namespace llvm {
39 namespace objcarc {
40 
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
43 /// relationships.
44 ///
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.
51  AliasAnalysis *AA;
52 
53  typedef std::pair<const Value *, const Value *> ValuePairTy;
55  CachedResultsTy CachedResults;
56 
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);
60 
61  void operator=(const ProvenanceAnalysis &) = delete;
62  ProvenanceAnalysis(const ProvenanceAnalysis &) = delete;
63 
64 public:
66 
67  void setAA(AliasAnalysis *aa) { AA = aa; }
68 
69  AliasAnalysis *getAA() const { return AA; }
70 
71  bool related(const Value *A, const Value *B, const DataLayout &DL);
72 
73  void clear() {
74  CachedResults.clear();
75  }
76 };
77 
78 } // end namespace objcarc
79 } // end namespace llvm
80 
81 #endif
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:109
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
This class represents the LLVM &#39;select&#39; instruction.
#define A
Definition: LargeTest.cpp:12
#define B
Definition: LargeTest.cpp:24
bool related(const Value *A, const Value *B, const DataLayout &DL)
LLVM Value Representation.
Definition: Value.h:73
This is similar to BasicAliasAnalysis, and it uses many of the same techniques, except it uses specia...