1 //===- ScalarEvolutionAliasAnalysis.h - SCEV-based AA -----------*- 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 /// \file
10 /// This is the interface for a SCEV-based alias analysis.
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_ANALYSIS_SCALAREVOLUTIONALIASANALYSIS_H
15 #define LLVM_ANALYSIS_SCALAREVOLUTIONALIASANALYSIS_H
16 
17 #include "llvm/Analysis/AliasAnalysis.h"
18 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
19 #include "llvm/IR/Function.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/Pass.h"
22 
23 namespace llvm {
24 
25 /// A simple alias analysis implementation that uses ScalarEvolution to answer
26 /// queries.
27 class SCEVAAResult : public AAResultBase<SCEVAAResult> {
28   ScalarEvolution &SE;
29 
30 public:
SCEVAAResult(ScalarEvolution & SE)31   explicit SCEVAAResult(ScalarEvolution &SE) : AAResultBase(), SE(SE) {}
SCEVAAResult(SCEVAAResult && Arg)32   SCEVAAResult(SCEVAAResult &&Arg) : AAResultBase(std::move(Arg)), SE(Arg.SE) {}
33 
34   AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB);
35 
36 private:
37   Value *GetBaseValue(const SCEV *S);
38 };
39 
40 /// Analysis pass providing a never-invalidated alias analysis result.
41 class SCEVAA : public AnalysisInfoMixin<SCEVAA> {
42   friend AnalysisInfoMixin<SCEVAA>;
43   static char PassID;
44 
45 public:
46   typedef SCEVAAResult Result;
47 
48   SCEVAAResult run(Function &F, AnalysisManager<Function> &AM);
49 };
50 
51 /// Legacy wrapper pass to provide the SCEVAAResult object.
52 class SCEVAAWrapperPass : public FunctionPass {
53   std::unique_ptr<SCEVAAResult> Result;
54 
55 public:
56   static char ID;
57 
58   SCEVAAWrapperPass();
59 
getResult()60   SCEVAAResult &getResult() { return *Result; }
getResult()61   const SCEVAAResult &getResult() const { return *Result; }
62 
63   bool runOnFunction(Function &F) override;
64   void getAnalysisUsage(AnalysisUsage &AU) const override;
65 };
66 
67 /// Creates an instance of \c SCEVAAWrapperPass.
68 FunctionPass *createSCEVAAWrapperPass();
69 
70 }
71 
72 #endif
73