//===- DependencyAnalysis.h - ObjC ARC Optimization ---*- C++ -*-----------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// /// \file /// /// This file declares special dependency analysis routines used in Objective C /// ARC Optimizations. /// /// WARNING: This file knows about certain library functions. It recognizes them /// by name, and hardwires knowledge of their semantics. /// /// WARNING: This file knows about how certain Objective-C library functions are /// used. Naive LLVM IR transformations which would otherwise be /// behavior-preserving may break these assumptions. /// //===----------------------------------------------------------------------===// #ifndef LLVM_LIB_TRANSFORMS_OBJCARC_DEPENDENCYANALYSIS_H #define LLVM_LIB_TRANSFORMS_OBJCARC_DEPENDENCYANALYSIS_H #include "llvm/Analysis/ObjCARCInstKind.h" namespace llvm { class BasicBlock; class Instruction; class Value; } namespace llvm { namespace objcarc { class ProvenanceAnalysis; /// \enum DependenceKind /// Defines different dependence kinds among various ARC constructs. /// /// There are several kinds of dependence-like concepts in use here. /// enum DependenceKind { … }; /// Find dependent instructions. If there is exactly one dependent instruction, /// return it. Otherwise, return null. llvm::Instruction *findSingleDependency(DependenceKind Flavor, const Value *Arg, BasicBlock *StartBB, Instruction *StartInst, ProvenanceAnalysis &PA); bool Depends(DependenceKind Flavor, Instruction *Inst, const Value *Arg, ProvenanceAnalysis &PA); /// Test whether the given instruction can "use" the given pointer's object in a /// way that requires the reference count to be positive. bool CanUse(const Instruction *Inst, const Value *Ptr, ProvenanceAnalysis &PA, ARCInstKind Class); /// Test whether the given instruction can result in a reference count /// modification (positive or negative) for the pointer's object. bool CanAlterRefCount(const Instruction *Inst, const Value *Ptr, ProvenanceAnalysis &PA, ARCInstKind Class); /// Returns true if we can not conservatively prove that Inst can not decrement /// the reference count of Ptr. Returns false if we can. bool CanDecrementRefCount(const Instruction *Inst, const Value *Ptr, ProvenanceAnalysis &PA, ARCInstKind Class); static inline bool CanDecrementRefCount(const Instruction *Inst, const Value *Ptr, ProvenanceAnalysis &PA) { … } } // namespace objcarc } // namespace llvm #endif