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      1 //===- TypeBasedAliasAnalysis.h - Type-Based Alias Analysis -----*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 /// \file
     11 /// This is the interface for a metadata-based TBAA. See the source file for
     12 /// details on the algorithm.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #ifndef LLVM_ANALYSIS_TYPEBASEDALIASANALYSIS_H
     17 #define LLVM_ANALYSIS_TYPEBASEDALIASANALYSIS_H
     18 
     19 #include "llvm/Analysis/AliasAnalysis.h"
     20 #include "llvm/IR/CallSite.h"
     21 #include "llvm/IR/PassManager.h"
     22 #include "llvm/Pass.h"
     23 #include <memory>
     24 
     25 namespace llvm {
     26 
     27 class Function;
     28 class MDNode;
     29 class MemoryLocation;
     30 
     31 /// A simple AA result that uses TBAA metadata to answer queries.
     32 class TypeBasedAAResult : public AAResultBase<TypeBasedAAResult> {
     33   friend AAResultBase<TypeBasedAAResult>;
     34 
     35 public:
     36   /// Handle invalidation events from the new pass manager.
     37   ///
     38   /// By definition, this result is stateless and so remains valid.
     39   bool invalidate(Function &, const PreservedAnalyses &,
     40                   FunctionAnalysisManager::Invalidator &) {
     41     return false;
     42   }
     43 
     44   AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB);
     45   bool pointsToConstantMemory(const MemoryLocation &Loc, bool OrLocal);
     46   FunctionModRefBehavior getModRefBehavior(ImmutableCallSite CS);
     47   FunctionModRefBehavior getModRefBehavior(const Function *F);
     48   ModRefInfo getModRefInfo(ImmutableCallSite CS, const MemoryLocation &Loc);
     49   ModRefInfo getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2);
     50 
     51 private:
     52   bool Aliases(const MDNode *A, const MDNode *B) const;
     53   bool PathAliases(const MDNode *A, const MDNode *B) const;
     54 };
     55 
     56 /// Analysis pass providing a never-invalidated alias analysis result.
     57 class TypeBasedAA : public AnalysisInfoMixin<TypeBasedAA> {
     58   friend AnalysisInfoMixin<TypeBasedAA>;
     59 
     60   static AnalysisKey Key;
     61 
     62 public:
     63   using Result = TypeBasedAAResult;
     64 
     65   TypeBasedAAResult run(Function &F, FunctionAnalysisManager &AM);
     66 };
     67 
     68 /// Legacy wrapper pass to provide the TypeBasedAAResult object.
     69 class TypeBasedAAWrapperPass : public ImmutablePass {
     70   std::unique_ptr<TypeBasedAAResult> Result;
     71 
     72 public:
     73   static char ID;
     74 
     75   TypeBasedAAWrapperPass();
     76 
     77   TypeBasedAAResult &getResult() { return *Result; }
     78   const TypeBasedAAResult &getResult() const { return *Result; }
     79 
     80   bool doInitialization(Module &M) override;
     81   bool doFinalization(Module &M) override;
     82   void getAnalysisUsage(AnalysisUsage &AU) const override;
     83 };
     84 
     85 //===--------------------------------------------------------------------===//
     86 //
     87 // createTypeBasedAAWrapperPass - This pass implements metadata-based
     88 // type-based alias analysis.
     89 //
     90 ImmutablePass *createTypeBasedAAWrapperPass();
     91 
     92 } // end namespace llvm
     93 
     94 #endif // LLVM_ANALYSIS_TYPEBASEDALIASANALYSIS_H
     95