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
26namespace llvm {
27
28class Function;
29class MemoryLocation;
30class TargetLibraryInfo;
31
32namespace cflaa {
33
34struct AliasSummary;
35
36} // end namespace cflaa
37
38class CFLAndersAAResult : public AAResultBase<CFLAndersAAResult> {
39  friend AAResultBase<CFLAndersAAResult>;
40
41  class FunctionInfo;
42
43public:
44  explicit CFLAndersAAResult(
45      std::function<const TargetLibraryInfo &(Function &F)> GetTLI);
46  CFLAndersAAResult(CFLAndersAAResult &&RHS);
47  ~CFLAndersAAResult();
48
49  /// Handle invalidation events from the new pass manager.
50  /// By definition, this result is stateless and so remains valid.
51  bool invalidate(Function &, const PreservedAnalyses &,
52                  FunctionAnalysisManager::Invalidator &) {
53    return false;
54  }
55
56  /// Evict the given function from cache
57  void evict(const Function *Fn);
58
59  /// Get the alias summary for the given function
60  /// Return nullptr if the summary is not found or not available
61  const cflaa::AliasSummary *getAliasSummary(const Function &);
62
63  AliasResult query(const MemoryLocation &, const MemoryLocation &);
64  AliasResult alias(const MemoryLocation &, const MemoryLocation &,
65                    AAQueryInfo &);
66
67private:
68  /// Ensures that the given function is available in the cache.
69  /// Returns the appropriate entry from the cache.
70  const Optional<FunctionInfo> &ensureCached(const Function &);
71
72  /// Inserts the given Function into the cache.
73  void scan(const Function &);
74
75  /// Build summary for a given function
76  FunctionInfo buildInfoFrom(const Function &);
77
78  std::function<const TargetLibraryInfo &(Function &F)> GetTLI;
79
80  /// Cached mapping of Functions to their StratifiedSets.
81  /// If a function's sets are currently being built, it is marked
82  /// in the cache as an Optional without a value. This way, if we
83  /// have any kind of recursion, it is discernable from a function
84  /// that simply has empty sets.
85  DenseMap<const Function *, Optional<FunctionInfo>> Cache;
86
87  std::forward_list<cflaa::FunctionHandle<CFLAndersAAResult>> Handles;
88};
89
90/// Analysis pass providing a never-invalidated alias analysis result.
91///
92/// FIXME: We really should refactor CFL to use the analysis more heavily, and
93/// in particular to leverage invalidation to trigger re-computation.
94class CFLAndersAA : public AnalysisInfoMixin<CFLAndersAA> {
95  friend AnalysisInfoMixin<CFLAndersAA>;
96
97  static AnalysisKey Key;
98
99public:
100  using Result = CFLAndersAAResult;
101
102  CFLAndersAAResult run(Function &F, FunctionAnalysisManager &AM);
103};
104
105/// Legacy wrapper pass to provide the CFLAndersAAResult object.
106class CFLAndersAAWrapperPass : public ImmutablePass {
107  std::unique_ptr<CFLAndersAAResult> Result;
108
109public:
110  static char ID;
111
112  CFLAndersAAWrapperPass();
113
114  CFLAndersAAResult &getResult() { return *Result; }
115  const CFLAndersAAResult &getResult() const { return *Result; }
116
117  void initializePass() override;
118  void getAnalysisUsage(AnalysisUsage &AU) const override;
119};
120
121// createCFLAndersAAWrapperPass - This pass implements a set-based approach to
122// alias analysis.
123ImmutablePass *createCFLAndersAAWrapperPass();
124
125} // end namespace llvm
126
127#endif // LLVM_ANALYSIS_CFLANDERSALIASANALYSIS_H
128