llvm/llvm/include/llvm/Analysis/MemoryDependenceAnalysis.h

//===- llvm/Analysis/MemoryDependenceAnalysis.h - Memory Deps ---*- 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
//
//===----------------------------------------------------------------------===//
//
// This file defines the MemoryDependenceAnalysis analysis pass.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_MEMORYDEPENDENCEANALYSIS_H
#define LLVM_ANALYSIS_MEMORYDEPENDENCEANALYSIS_H

#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/PointerEmbeddedInt.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/PointerSumType.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/PredIteratorCache.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Pass.h"
#include <optional>

namespace llvm {

class AssumptionCache;
class DominatorTree;
class PHITransAddr;

/// A memory dependence query can return one of three different answers.
class MemDepResult { … };

/// This is an entry in the NonLocalDepInfo cache.
///
/// For each BasicBlock (the BB entry) it keeps a MemDepResult.
class NonLocalDepEntry { … };

/// This is a result from a NonLocal dependence query.
///
/// For each BasicBlock (the BB entry) it keeps a MemDepResult and the
/// (potentially phi translated) address that was live in the block.
class NonLocalDepResult { … };

/// Provides a lazy, caching interface for making common memory aliasing
/// information queries, backed by LLVM's alias analysis passes.
///
/// The dependency information returned is somewhat unusual, but is pragmatic.
/// If queried about a store or call that might modify memory, the analysis
/// will return the instruction[s] that may either load from that memory or
/// store to it.  If queried with a load or call that can never modify memory,
/// the analysis will return calls and stores that might modify the pointer,
/// but generally does not return loads unless a) they are volatile, or
/// b) they load from *must-aliased* pointers.  Returning a dependence on
/// must-alias'd pointers instead of all pointers interacts well with the
/// internal caching mechanism.
class MemoryDependenceResults { … };

/// An analysis that produces \c MemoryDependenceResults for a function.
///
/// This is essentially a no-op because the results are computed entirely
/// lazily.
class MemoryDependenceAnalysis
    : public AnalysisInfoMixin<MemoryDependenceAnalysis> { … };

/// A wrapper analysis pass for the legacy pass manager that exposes a \c
/// MemoryDepnedenceResults instance.
class MemoryDependenceWrapperPass : public FunctionPass { … };

} // end namespace llvm

#endif // LLVM_ANALYSIS_MEMORYDEPENDENCEANALYSIS_H