TypeBasedAliasAnalysis.h

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//===- TypeBasedAliasAnalysis.h - Type-Based Alias Analysis -----*- 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
//
//===----------------------------------------------------------------------===//
//
/// \file
/// This is the interface for a metadata-based TBAA. See the source file for
/// details on the algorithm.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_ANALYSIS_TYPEBASEDALIASANALYSIS_H
#define LLVM_ANALYSIS_TYPEBASEDALIASANALYSIS_H
 
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
#include <memory>
 
namespace llvm {
 
class CallBase;
class Function;
class MDNode;
class MemoryLocation;
 
/// A simple AA result that uses TBAA metadata to answer queries.
class TypeBasedAAResult : public AAResultBase {
  /// True if type sanitizer is enabled. When TypeSanitizer is used, don't use
  /// TBAA information for alias analysis as  this might cause us to remove
  /// memory accesses that we need to verify at runtime.
  bool UsingTypeSanitizer;
 
public:
  TypeBasedAAResult(bool UsingTypeSanitizer)
      : UsingTypeSanitizer(UsingTypeSanitizer) {}
 
  /// Handle invalidation events from the new pass manager.
  ///
  /// By definition, this result is stateless and so remains valid.
  bool invalidate(Function &, const PreservedAnalyses &,
                  FunctionAnalysisManager::Invalidator &) {
    return false;
  }
 
  AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
                    AAQueryInfo &AAQI, const Instruction *CtxI);
  ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI,
                               bool IgnoreLocals);
 
  MemoryEffects getMemoryEffects(const CallBase *Call, AAQueryInfo &AAQI);
  MemoryEffects getMemoryEffects(const Function *F);
  ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
                           AAQueryInfo &AAQI);
  ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2,
                           AAQueryInfo &AAQI);
 
private:
  bool Aliases(const MDNode *A, const MDNode *B) const;
 
  /// Returns true if TBAA metadata should be used, that is if TBAA is enabled
  /// and type sanitizer is not used.
  bool shouldUseTBAA() const;
};
 
/// Analysis pass providing a never-invalidated alias analysis result.
class TypeBasedAA : public AnalysisInfoMixin<TypeBasedAA> {
  friend AnalysisInfoMixin<TypeBasedAA>;
 
  static AnalysisKey Key;
 
public:
  using Result = TypeBasedAAResult;
 
  TypeBasedAAResult run(Function &F, FunctionAnalysisManager &AM);
};
 
/// Legacy wrapper pass to provide the TypeBasedAAResult object.
class TypeBasedAAWrapperPass : public ImmutablePass {
  std::unique_ptr<TypeBasedAAResult> Result;
 
public:
  static char ID;
 
  TypeBasedAAWrapperPass();
 
  TypeBasedAAResult &getResult() { return *Result; }
  const TypeBasedAAResult &getResult() const { return *Result; }
 
  bool doInitialization(Module &M) override;
  bool doFinalization(Module &M) override;
  void getAnalysisUsage(AnalysisUsage &AU) const override;
};
 
//===--------------------------------------------------------------------===//
//
// createTypeBasedAAWrapperPass - This pass implements metadata-based
// type-based alias analysis.
//
ImmutablePass *createTypeBasedAAWrapperPass();
 
} // end namespace llvm
 
#endif // LLVM_ANALYSIS_TYPEBASEDALIASANALYSIS_H