1327952Sdim//===- ProvenanceAnalysis.h - ObjC ARC Optimization -------------*- C++ -*-===// 2249259Sdim// 3353358Sdim// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4353358Sdim// See https://llvm.org/LICENSE.txt for license information. 5353358Sdim// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6249259Sdim// 7249259Sdim//===----------------------------------------------------------------------===// 8327952Sdim// 9249259Sdim/// \file 10249259Sdim/// 11249259Sdim/// This file declares a special form of Alias Analysis called ``Provenance 12249259Sdim/// Analysis''. The word ``provenance'' refers to the history of the ownership 13249259Sdim/// of an object. Thus ``Provenance Analysis'' is an analysis which attempts to 14249259Sdim/// use various techniques to determine if locally 15249259Sdim/// 16249259Sdim/// WARNING: This file knows about certain library functions. It recognizes them 17249259Sdim/// by name, and hardwires knowledge of their semantics. 18249259Sdim/// 19249259Sdim/// WARNING: This file knows about how certain Objective-C library functions are 20249259Sdim/// used. Naive LLVM IR transformations which would otherwise be 21249259Sdim/// behavior-preserving may break these assumptions. 22327952Sdim// 23249259Sdim//===----------------------------------------------------------------------===// 24249259Sdim 25280031Sdim#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H 26280031Sdim#define LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H 27249259Sdim 28249259Sdim#include "llvm/ADT/DenseMap.h" 29296417Sdim#include "llvm/Analysis/AliasAnalysis.h" 30341825Sdim#include "llvm/IR/ValueHandle.h" 31327952Sdim#include <utility> 32249259Sdim 33249259Sdimnamespace llvm { 34249259Sdim 35327952Sdimclass DataLayout; 36327952Sdimclass PHINode; 37327952Sdimclass SelectInst; 38327952Sdimclass Value; 39327952Sdim 40249259Sdimnamespace objcarc { 41249259Sdim 42341825Sdim/// This is similar to BasicAliasAnalysis, and it uses many of the same 43249259Sdim/// techniques, except it uses special ObjC-specific reasoning about pointer 44249259Sdim/// relationships. 45249259Sdim/// 46249259Sdim/// In this context ``Provenance'' is defined as the history of an object's 47249259Sdim/// ownership. Thus ``Provenance Analysis'' is defined by using the notion of 48249259Sdim/// an ``independent provenance source'' of a pointer to determine whether or 49249259Sdim/// not two pointers have the same provenance source and thus could 50249259Sdim/// potentially be related. 51249259Sdimclass ProvenanceAnalysis { 52249259Sdim AliasAnalysis *AA; 53249259Sdim 54327952Sdim using ValuePairTy = std::pair<const Value *, const Value *>; 55327952Sdim using CachedResultsTy = DenseMap<ValuePairTy, bool>; 56327952Sdim 57249259Sdim CachedResultsTy CachedResults; 58249259Sdim 59341825Sdim DenseMap<const Value *, WeakTrackingVH> UnderlyingObjCPtrCache; 60341825Sdim 61288943Sdim bool relatedCheck(const Value *A, const Value *B, const DataLayout &DL); 62249259Sdim bool relatedSelect(const SelectInst *A, const Value *B); 63249259Sdim bool relatedPHI(const PHINode *A, const Value *B); 64249259Sdim 65327952Sdimpublic: 66327952Sdim ProvenanceAnalysis() = default; 67288943Sdim ProvenanceAnalysis(const ProvenanceAnalysis &) = delete; 68327952Sdim ProvenanceAnalysis &operator=(const ProvenanceAnalysis &) = delete; 69249259Sdim 70249259Sdim void setAA(AliasAnalysis *aa) { AA = aa; } 71249259Sdim 72249259Sdim AliasAnalysis *getAA() const { return AA; } 73249259Sdim 74288943Sdim bool related(const Value *A, const Value *B, const DataLayout &DL); 75249259Sdim 76249259Sdim void clear() { 77249259Sdim CachedResults.clear(); 78341825Sdim UnderlyingObjCPtrCache.clear(); 79249259Sdim } 80249259Sdim}; 81249259Sdim 82249259Sdim} // end namespace objcarc 83327952Sdim 84249259Sdim} // end namespace llvm 85249259Sdim 86327952Sdim#endif // LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H 87