include/llvm/Analysis/CFLAndersAliasAnalysis.h

   1 //==- CFLAndersAliasAnalysis.h - Unification-based Alias Analysis -*- C++-*-==//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 /// \file
   9 /// This is the interface for LLVM's inclusion-based alias analysis
  10 /// implemented with CFL graph reachability.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_ANALYSIS_CFLANDERSALIASANALYSIS_H
  15 #define LLVM_ANALYSIS_CFLANDERSALIASANALYSIS_H
  16
  17 #include "llvm/ADT/DenseMap.h"
  18 #include "llvm/ADT/Optional.h"
  19 #include "llvm/Analysis/AliasAnalysis.h"
  20 #include "llvm/Analysis/CFLAliasAnalysisUtils.h"
  21 #include "llvm/IR/PassManager.h"
  22 #include "llvm/Pass.h"
  23 #include <forward_list>
  24 #include <memory>
  25
  26 namespace llvm {
  27
  28 class Function;
  29 class MemoryLocation;
  30 class TargetLibraryInfo;
  31
  32 namespace cflaa {
  33
  34 struct AliasSummary;
  35
  36 } // end namespace cflaa
  37
  38 class CFLAndersAAResult : public AAResultBase<CFLAndersAAResult> {
  39   friend AAResultBase<CFLAndersAAResult>;
  40
  41   class FunctionInfo;
  42
  43 public:
  44   explicit CFLAndersAAResult(const TargetLibraryInfo &TLI);
  45   CFLAndersAAResult(CFLAndersAAResult &&RHS);
  46   ~CFLAndersAAResult();
  47
  48   /// Handle invalidation events from the new pass manager.
  49   /// By definition, this result is stateless and so remains valid.
  50   bool invalidate(Function &, const PreservedAnalyses &,
  51                   FunctionAnalysisManager::Invalidator &) {
  52     return false;
  53   }
  54
  55   /// Evict the given function from cache
  56   void evict(const Function *Fn);
  57
  58   /// Get the alias summary for the given function
  59   /// Return nullptr if the summary is not found or not available
  60   const cflaa::AliasSummary *getAliasSummary(const Function &);
  61
  62   AliasResult query(const MemoryLocation &, const MemoryLocation &);
  63   AliasResult alias(const MemoryLocation &, const MemoryLocation &);
  64
  65 private:
  66   /// Ensures that the given function is available in the cache.
  67   /// Returns the appropriate entry from the cache.
  68   const Optional<FunctionInfo> &ensureCached(const Function &);
  69
  70   /// Inserts the given Function into the cache.
  71   void scan(const Function &);
  72
  73   /// Build summary for a given function
  74   FunctionInfo buildInfoFrom(const Function &);
  75
  76   const TargetLibraryInfo &TLI;
  77
  78   /// Cached mapping of Functions to their StratifiedSets.
  79   /// If a function's sets are currently being built, it is marked
  80   /// in the cache as an Optional without a value. This way, if we
  81   /// have any kind of recursion, it is discernable from a function
  82   /// that simply has empty sets.
  83   DenseMap<const Function *, Optional<FunctionInfo>> Cache;
  84
  85   std::forward_list<cflaa::FunctionHandle<CFLAndersAAResult>> Handles;
  86 };
  87
  88 /// Analysis pass providing a never-invalidated alias analysis result.
  89 ///
  90 /// FIXME: We really should refactor CFL to use the analysis more heavily, and
  91 /// in particular to leverage invalidation to trigger re-computation.
  92 class CFLAndersAA : public AnalysisInfoMixin<CFLAndersAA> {
  93   friend AnalysisInfoMixin<CFLAndersAA>;
  94
  95   static AnalysisKey Key;
  96
  97 public:
  98   using Result = CFLAndersAAResult;
  99
 100   CFLAndersAAResult run(Function &F, FunctionAnalysisManager &AM);
 101 };
 102
 103 /// Legacy wrapper pass to provide the CFLAndersAAResult object.
 104 class CFLAndersAAWrapperPass : public ImmutablePass {
 105   std::unique_ptr<CFLAndersAAResult> Result;
 106
 107 public:
 108   static char ID;
 109
 110   CFLAndersAAWrapperPass();
 111
 112   CFLAndersAAResult &getResult() { return *Result; }
 113   const CFLAndersAAResult &getResult() const { return *Result; }
 114
 115   void initializePass() override;
 116   void getAnalysisUsage(AnalysisUsage &AU) const override;
 117 };
 118
 119 // createCFLAndersAAWrapperPass - This pass implements a set-based approach to
 120 // alias analysis.
 121 ImmutablePass *createCFLAndersAAWrapperPass();
 122
 123 } // end namespace llvm
 124
 125 #endif // LLVM_ANALYSIS_CFLANDERSALIASANALYSIS_H