File: LazyValueInfo.h

package info (click to toggle)
llvm-toolchain-6.0 1:6.0.1-10
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 598,080 kB
  • sloc: cpp: 3,046,253; ansic: 595,057; asm: 271,965; python: 128,926; objc: 106,554; sh: 21,906; lisp: 10,191; pascal: 6,094; ml: 5,544; perl: 5,265; makefile: 2,227; cs: 2,027; xml: 686; php: 212; csh: 117
file content (167 lines) | stat: -rw-r--r-- 5,910 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
//===- LazyValueInfo.h - Value constraint analysis --------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the interface for lazy computation of value constraint
// information.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_LAZYVALUEINFO_H
#define LLVM_ANALYSIS_LAZYVALUEINFO_H

#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"

namespace llvm {
  class AssumptionCache;
  class Constant;
  class ConstantRange;
  class DataLayout;
  class DominatorTree;
  class Instruction;
  class TargetLibraryInfo;
  class Value;

/// This pass computes, caches, and vends lazy value constraint information.
class LazyValueInfo {
  friend class LazyValueInfoWrapperPass;
  AssumptionCache *AC = nullptr;
  const DataLayout *DL = nullptr;
  class TargetLibraryInfo *TLI = nullptr;
  DominatorTree *DT = nullptr;
  void *PImpl = nullptr;
  LazyValueInfo(const LazyValueInfo&) = delete;
  void operator=(const LazyValueInfo&) = delete;
public:
  ~LazyValueInfo();
  LazyValueInfo() {}
  LazyValueInfo(AssumptionCache *AC_, const DataLayout *DL_, TargetLibraryInfo *TLI_,
                DominatorTree *DT_)
      : AC(AC_), DL(DL_), TLI(TLI_), DT(DT_) {}
  LazyValueInfo(LazyValueInfo &&Arg)
      : AC(Arg.AC), DL(Arg.DL), TLI(Arg.TLI), DT(Arg.DT), PImpl(Arg.PImpl) {
    Arg.PImpl = nullptr;
  }
  LazyValueInfo &operator=(LazyValueInfo &&Arg) {
    releaseMemory();
    AC = Arg.AC;
    DL = Arg.DL;
    TLI = Arg.TLI;
    DT = Arg.DT;
    PImpl = Arg.PImpl;
    Arg.PImpl = nullptr;
    return *this;
  }

  /// This is used to return true/false/dunno results.
  enum Tristate {
    Unknown = -1, False = 0, True = 1
  };

  // Public query interface.

  /// Determine whether the specified value comparison with a constant is known
  /// to be true or false on the specified CFG edge.
  /// Pred is a CmpInst predicate.
  Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
                              BasicBlock *FromBB, BasicBlock *ToBB,
                              Instruction *CxtI = nullptr);

  /// Determine whether the specified value comparison with a constant is known
  /// to be true or false at the specified instruction
  /// (from an assume intrinsic). Pred is a CmpInst predicate.
  Tristate getPredicateAt(unsigned Pred, Value *V, Constant *C,
                          Instruction *CxtI);

  /// Determine whether the specified value is known to be a
  /// constant at the end of the specified block.  Return null if not.
  Constant *getConstant(Value *V, BasicBlock *BB, Instruction *CxtI = nullptr);

  /// Return the ConstantRange constraint that is known to hold for the
  /// specified value at the end of the specified block. This may only be called
  /// on integer-typed Values.
  ConstantRange getConstantRange(Value *V, BasicBlock *BB, Instruction *CxtI = nullptr);

  /// Determine whether the specified value is known to be a
  /// constant on the specified edge.  Return null if not.
  Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB,
                              Instruction *CxtI = nullptr);

  /// Return the ConstantRage constraint that is known to hold for the
  /// specified value on the specified edge. This may be only be called
  /// on integer-typed Values.
  ConstantRange getConstantRangeOnEdge(Value *V, BasicBlock *FromBB,
                                       BasicBlock *ToBB,
                                       Instruction *CxtI = nullptr);

  /// Inform the analysis cache that we have threaded an edge from
  /// PredBB to OldSucc to be from PredBB to NewSucc instead.
  void threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, BasicBlock *NewSucc);

  /// Inform the analysis cache that we have erased a block.
  void eraseBlock(BasicBlock *BB);

  /// Print the \LazyValueInfo Analysis.
  /// We pass in the DTree that is required for identifying which basic blocks
  /// we can solve/print for, in the LVIPrinter. The DT is optional
  /// in LVI, so we need to pass it here as an argument.
  void printLVI(Function &F, DominatorTree &DTree, raw_ostream &OS);

  /// Disables use of the DominatorTree within LVI.
  void disableDT();

  /// Enables use of the DominatorTree within LVI. Does nothing if the class
  /// instance was initialized without a DT pointer.
  void enableDT();

  // For old PM pass. Delete once LazyValueInfoWrapperPass is gone.
  void releaseMemory();

  /// Handle invalidation events in the new pass manager.
  bool invalidate(Function &F, const PreservedAnalyses &PA,
                  FunctionAnalysisManager::Invalidator &Inv);
};

/// \brief Analysis to compute lazy value information.
class LazyValueAnalysis : public AnalysisInfoMixin<LazyValueAnalysis> {
public:
  typedef LazyValueInfo Result;
  Result run(Function &F, FunctionAnalysisManager &FAM);

private:
  static AnalysisKey Key;
  friend struct AnalysisInfoMixin<LazyValueAnalysis>;
};

/// Wrapper around LazyValueInfo.
class LazyValueInfoWrapperPass : public FunctionPass {
  LazyValueInfoWrapperPass(const LazyValueInfoWrapperPass&) = delete;
  void operator=(const LazyValueInfoWrapperPass&) = delete;
public:
  static char ID;
  LazyValueInfoWrapperPass() : FunctionPass(ID) {
    initializeLazyValueInfoWrapperPassPass(*PassRegistry::getPassRegistry());
  }
  ~LazyValueInfoWrapperPass() override {
    assert(!Info.PImpl && "releaseMemory not called");
  }

  LazyValueInfo &getLVI();

  void getAnalysisUsage(AnalysisUsage &AU) const override;
  void releaseMemory() override;
  bool runOnFunction(Function &F) override;
private:
  LazyValueInfo Info;
};

}  // end namespace llvm

#endif