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 30namespace llvm { 31 class Value; 32 class AliasAnalysis; 33 class PHINode; 34 class SelectInst; 35} 36 37namespace llvm { 38namespace 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. 49class 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 63public: 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