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//===- ProvenanceAnalysis.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 special form of Alias Analysis called ``Provenance
/// Analysis''. The word ``provenance'' refers to the history of the ownership
/// of an object. Thus ``Provenance Analysis'' is an analysis which attempts to
/// use various techniques to determine if locally
///
/// 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_PROVENANCEANALYSIS_H
#define LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H
#include "llvm/ADT/DenseMap.h"
namespace llvm {
class Value;
class AliasAnalysis;
class PHINode;
class SelectInst;
}
namespace llvm {
namespace objcarc {
/// \brief This is similar to BasicAliasAnalysis, and it uses many of the same
/// techniques, except it uses special ObjC-specific reasoning about pointer
/// relationships.
///
/// In this context ``Provenance'' is defined as the history of an object's
/// ownership. Thus ``Provenance Analysis'' is defined by using the notion of
/// an ``independent provenance source'' of a pointer to determine whether or
/// not two pointers have the same provenance source and thus could
/// potentially be related.
class ProvenanceAnalysis {
AliasAnalysis *AA;
typedef std::pair<const Value *, const Value *> ValuePairTy;
typedef DenseMap<ValuePairTy, bool> CachedResultsTy;
CachedResultsTy CachedResults;
bool relatedCheck(const Value *A, const Value *B);
bool relatedSelect(const SelectInst *A, const Value *B);
bool relatedPHI(const PHINode *A, const Value *B);
void operator=(const ProvenanceAnalysis &) LLVM_DELETED_FUNCTION;
ProvenanceAnalysis(const ProvenanceAnalysis &) LLVM_DELETED_FUNCTION;
public:
ProvenanceAnalysis() {}
void setAA(AliasAnalysis *aa) { AA = aa; }
AliasAnalysis *getAA() const { return AA; }
bool related(const Value *A, const Value *B);
void clear() {
CachedResults.clear();
}
};
} // end namespace objcarc
} // end namespace llvm
#endif
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