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_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H 26 #define LLVM_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H 27 28 #include "llvm/ADT/DenseMap.h" 29 30 namespace llvm { 31 class Value; 32 class AliasAnalysis; 33 class PHINode; 34 class SelectInst; 35 } 36 37 namespace llvm { 38 namespace objcarc { 39 40 /// \brief This is similar to BasicAliasAnalysis, and it uses many of the same 41 /// techniques, except it uses special ObjC-specific reasoning about pointer 42 /// relationships. 43 /// 44 /// In this context ``Provenance'' is defined as the history of an object's 45 /// ownership. Thus ``Provenance Analysis'' is defined by using the notion of 46 /// an ``independent provenance source'' of a pointer to determine whether or 47 /// not two pointers have the same provenance source and thus could 48 /// potentially be related. 49 class ProvenanceAnalysis { 50 AliasAnalysis *AA; 51 52 typedef std::pair<const Value *, const Value *> ValuePairTy; 53 typedef DenseMap<ValuePairTy, bool> CachedResultsTy; 54 CachedResultsTy CachedResults; 55 56 bool relatedCheck(const Value *A, const Value *B); 57 bool relatedSelect(const SelectInst *A, const Value *B); 58 bool relatedPHI(const PHINode *A, const Value *B); 59 60 void operator=(const ProvenanceAnalysis &) LLVM_DELETED_FUNCTION; 61 ProvenanceAnalysis(const ProvenanceAnalysis &) LLVM_DELETED_FUNCTION; 62 63 public: 64 ProvenanceAnalysis() {} 65 66 void setAA(AliasAnalysis *aa) { AA = aa; } 67 68 AliasAnalysis *getAA() const { return AA; } 69 70 bool related(const Value *A, const Value *B); 71 72 void clear() { 73 CachedResults.clear(); 74 } 75 }; 76 77 } // end namespace objcarc 78 } // end namespace llvm 79 80 #endif // LLVM_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H 81
