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//===- MemoryLocation.h - Memory location descriptions ----------*- 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 provides utility analysis objects describing memory locations.
/// These are used both by the Alias Analysis infrastructure and more
/// specialized memory analysis layers.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_MEMORYLOCATION_H
#define LLVM_ANALYSIS_MEMORYLOCATION_H
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Metadata.h"
namespace llvm {
class LoadInst;
class StoreInst;
class MemTransferInst;
class MemIntrinsic;
class AtomicMemTransferInst;
class AtomicMemIntrinsic;
class AnyMemTransferInst;
class AnyMemIntrinsic;
class TargetLibraryInfo;
// Represents the size of a MemoryLocation. Logically, it's an
// Optional<uint64_t>, with a special UnknownSize value from `MemoryLocation`.
using LocationSize = uint64_t;
/// Representation for a specific memory location.
///
/// This abstraction can be used to represent a specific location in memory.
/// The goal of the location is to represent enough information to describe
/// abstract aliasing, modification, and reference behaviors of whatever
/// value(s) are stored in memory at the particular location.
///
/// The primary user of this interface is LLVM's Alias Analysis, but other
/// memory analyses such as MemoryDependence can use it as well.
class MemoryLocation {
public:
/// UnknownSize - This is a special value which can be used with the
/// size arguments in alias queries to indicate that the caller does not
/// know the sizes of the potential memory references.
enum : uint64_t { UnknownSize = ~UINT64_C(0) };
/// The address of the start of the location.
const Value *Ptr;
/// The maximum size of the location, in address-units, or
/// UnknownSize if the size is not known.
///
/// Note that an unknown size does not mean the pointer aliases the entire
/// virtual address space, because there are restrictions on stepping out of
/// one object and into another. See
/// http://llvm.org/docs/LangRef.html#pointeraliasing
LocationSize Size;
/// The metadata nodes which describes the aliasing of the location (each
/// member is null if that kind of information is unavailable).
AAMDNodes AATags;
/// Return a location with information about the memory reference by the given
/// instruction.
static MemoryLocation get(const LoadInst *LI);
static MemoryLocation get(const StoreInst *SI);
static MemoryLocation get(const VAArgInst *VI);
static MemoryLocation get(const AtomicCmpXchgInst *CXI);
static MemoryLocation get(const AtomicRMWInst *RMWI);
static MemoryLocation get(const Instruction *Inst) {
return *MemoryLocation::getOrNone(Inst);
}
static Optional<MemoryLocation> getOrNone(const Instruction *Inst) {
switch (Inst->getOpcode()) {
case Instruction::Load:
return get(cast<LoadInst>(Inst));
case Instruction::Store:
return get(cast<StoreInst>(Inst));
case Instruction::VAArg:
return get(cast<VAArgInst>(Inst));
case Instruction::AtomicCmpXchg:
return get(cast<AtomicCmpXchgInst>(Inst));
case Instruction::AtomicRMW:
return get(cast<AtomicRMWInst>(Inst));
default:
return None;
}
}
/// Return a location representing the source of a memory transfer.
static MemoryLocation getForSource(const MemTransferInst *MTI);
static MemoryLocation getForSource(const AtomicMemTransferInst *MTI);
static MemoryLocation getForSource(const AnyMemTransferInst *MTI);
/// Return a location representing the destination of a memory set or
/// transfer.
static MemoryLocation getForDest(const MemIntrinsic *MI);
static MemoryLocation getForDest(const AtomicMemIntrinsic *MI);
static MemoryLocation getForDest(const AnyMemIntrinsic *MI);
/// Return a location representing a particular argument of a call.
static MemoryLocation getForArgument(ImmutableCallSite CS, unsigned ArgIdx,
const TargetLibraryInfo &TLI);
explicit MemoryLocation(const Value *Ptr = nullptr,
LocationSize Size = UnknownSize,
const AAMDNodes &AATags = AAMDNodes())
: Ptr(Ptr), Size(Size), AATags(AATags) {}
MemoryLocation getWithNewPtr(const Value *NewPtr) const {
MemoryLocation Copy(*this);
Copy.Ptr = NewPtr;
return Copy;
}
MemoryLocation getWithNewSize(LocationSize NewSize) const {
MemoryLocation Copy(*this);
Copy.Size = NewSize;
return Copy;
}
MemoryLocation getWithoutAATags() const {
MemoryLocation Copy(*this);
Copy.AATags = AAMDNodes();
return Copy;
}
bool operator==(const MemoryLocation &Other) const {
return Ptr == Other.Ptr && Size == Other.Size && AATags == Other.AATags;
}
};
// Specialize DenseMapInfo for MemoryLocation.
template <> struct DenseMapInfo<MemoryLocation> {
static inline MemoryLocation getEmptyKey() {
return MemoryLocation(DenseMapInfo<const Value *>::getEmptyKey(), 0);
}
static inline MemoryLocation getTombstoneKey() {
return MemoryLocation(DenseMapInfo<const Value *>::getTombstoneKey(), 0);
}
static unsigned getHashValue(const MemoryLocation &Val) {
return DenseMapInfo<const Value *>::getHashValue(Val.Ptr) ^
DenseMapInfo<LocationSize>::getHashValue(Val.Size) ^
DenseMapInfo<AAMDNodes>::getHashValue(Val.AATags);
}
static bool isEqual(const MemoryLocation &LHS, const MemoryLocation &RHS) {
return LHS == RHS;
}
};
}
#endif
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