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