forked from OSchip/llvm-project
75 lines
2.9 KiB
C++
75 lines
2.9 KiB
C++
//===- ObjCARCAliasAnalysis.h - ObjC ARC Optimization -*- C++ -*-----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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/// \file
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/// This file declares a simple ARC-aware AliasAnalysis using special knowledge
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/// of Objective C to enhance other optimization passes which rely on the Alias
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/// Analysis infrastructure.
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///
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/// WARNING: This file knows about certain library functions. It recognizes them
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/// by name, and hardwires knowledge of their semantics.
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///
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/// WARNING: This file knows about how certain Objective-C library functions are
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/// used. Naive LLVM IR transformations which would otherwise be
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/// behavior-preserving may break these assumptions.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARCALIASANALYSIS_H
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#define LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARCALIASANALYSIS_H
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Pass.h"
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namespace llvm {
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namespace objcarc {
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/// \brief This is a simple alias analysis implementation that uses knowledge
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/// of ARC constructs to answer queries.
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///
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/// TODO: This class could be generalized to know about other ObjC-specific
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/// tricks. Such as knowing that ivars in the non-fragile ABI are non-aliasing
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/// even though their offsets are dynamic.
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class ObjCARCAliasAnalysis : public ImmutablePass,
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public AliasAnalysis {
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public:
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static char ID; // Class identification, replacement for typeinfo
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ObjCARCAliasAnalysis() : ImmutablePass(ID) {
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initializeObjCARCAliasAnalysisPass(*PassRegistry::getPassRegistry());
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}
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private:
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void initializePass() override {
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InitializeAliasAnalysis(this);
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}
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/// This method is used when a pass implements an analysis interface through
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/// multiple inheritance. If needed, it should override this to adjust the
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/// this pointer as needed for the specified pass info.
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void *getAdjustedAnalysisPointer(const void *PI) override {
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if (PI == &AliasAnalysis::ID)
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return static_cast<AliasAnalysis *>(this);
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return this;
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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AliasResult alias(const Location &LocA, const Location &LocB) override;
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bool pointsToConstantMemory(const Location &Loc, bool OrLocal) override;
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ModRefBehavior getModRefBehavior(ImmutableCallSite CS) override;
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ModRefBehavior getModRefBehavior(const Function *F) override;
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ModRefResult getModRefInfo(ImmutableCallSite CS,
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const Location &Loc) override;
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ModRefResult getModRefInfo(ImmutableCallSite CS1,
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ImmutableCallSite CS2) override;
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};
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} // namespace objcarc
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} // namespace llvm
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#endif
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