LoopPass.h revision d8ac1be6862c0611cc0b3a726ad4c3141e7a3d9e 
1//===- LoopPass.h - LoopPass class ----------------------------------------===//
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// This file defines LoopPass class. All loop optimization
11// and transformation passes are derived from LoopPass.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_LOOP_PASS_H
16#define LLVM_LOOP_PASS_H
17
18#include "llvm/Analysis/LoopInfo.h"
19#include "llvm/Pass.h"
20#include "llvm/PassManagers.h"
21#include "llvm/Function.h"
22
23namespace llvm {
24
25class LPPassManager;
26class Function;
27class PMStack;
28
29class LoopPass : public Pass {
30public:
31  explicit LoopPass(intptr_t pid) : Pass(pid) {}
32  explicit LoopPass(void *pid) : Pass(pid) {}
33
34  // runOnLoop - This method should be implemented by the subclass to perform
35  // whatever action is necessary for the specified Loop.
36  virtual bool runOnLoop(Loop *L, LPPassManager &LPM) = 0;
37
38  // Initialization and finalization hooks.
39  virtual bool doInitialization(Loop *L, LPPassManager &LPM) {
40    return false;
41  }
42
43  // Finalization hook does not supply Loop because at this time
44  // loop nest is completely different.
45  virtual bool doFinalization() { return false; }
46
47  // Check if this pass is suitable for the current LPPassManager, if
48  // available. This pass P is not suitable for a LPPassManager if P
49  // is not preserving higher level analysis info used by other
50  // LPPassManager passes. In such case, pop LPPassManager from the
51  // stack. This will force assignPassManager() to create new
52  // LPPassManger as expected.
53  void preparePassManager(PMStack &PMS);
54
55  /// Assign pass manager to manager this pass
56  virtual void assignPassManager(PMStack &PMS,
57                                 PassManagerType PMT = PMT_LoopPassManager);
58
59  ///  Return what kind of Pass Manager can manage this pass.
60  virtual PassManagerType getPotentialPassManagerType() const {
61    return PMT_LoopPassManager;
62  }
63
64  //===--------------------------------------------------------------------===//
65  /// SimpleAnalysis - Provides simple interface to update analysis info
66  /// maintained by various passes. Note, if required this interface can
67  /// be extracted into a separate abstract class but it would require
68  /// additional use of multiple inheritance in Pass class hierarchy, something
69  /// we are trying to avoid.
70
71  /// Each loop pass can override these simple analysis hooks to update
72  /// desired analysis information.
73  /// cloneBasicBlockAnalysis - Clone analysis info associated with basic block.
74  virtual void cloneBasicBlockAnalysis(BasicBlock *F, BasicBlock *T, Loop *L) {}
75
76  /// deletekAnalysisValue - Delete analysis info associated with value V.
77  virtual void deleteAnalysisValue(Value *V, Loop *L) {}
78};
79
80class LPPassManager : public FunctionPass, public PMDataManager {
81public:
82  static char ID;
83  explicit LPPassManager(int Depth);
84
85  /// run - Execute all of the passes scheduled for execution.  Keep track of
86  /// whether any of the passes modifies the module, and if so, return true.
87  bool runOnFunction(Function &F);
88
89  /// Pass Manager itself does not invalidate any analysis info.
90  // LPPassManager needs LoopInfo.
91  void getAnalysisUsage(AnalysisUsage &Info) const;
92
93  virtual const char *getPassName() const {
94    return "Loop Pass Manager";
95  }
96
97  /// Print passes managed by this manager
98  void dumpPassStructure(unsigned Offset);
99
100  Pass *getContainedPass(unsigned N) {
101    assert(N < PassVector.size() && "Pass number out of range!");
102    Pass *FP = static_cast<Pass *>(PassVector[N]);
103    return FP;
104  }
105
106  virtual PassManagerType getPassManagerType() const {
107    return PMT_LoopPassManager;
108  }
109
110public:
111  // Delete loop from the loop queue and loop nest (LoopInfo).
112  void deleteLoopFromQueue(Loop *L);
113
114  // Insert loop into the loop nest(LoopInfo) and loop queue(LQ).
115  void insertLoop(Loop *L, Loop *ParentLoop);
116
117  // Reoptimize this loop. LPPassManager will re-insert this loop into the
118  // queue. This allows LoopPass to change loop nest for the loop. This
119  // utility may send LPPassManager into infinite loops so use caution.
120  void redoLoop(Loop *L);
121
122  //===--------------------------------------------------------------------===//
123  /// SimpleAnalysis - Provides simple interface to update analysis info
124  /// maintained by various passes. Note, if required this interface can
125  /// be extracted into a separate abstract class but it would require
126  /// additional use of multiple inheritance in Pass class hierarchy, something
127  /// we are trying to avoid.
128
129  /// cloneBasicBlockSimpleAnalysis - Invoke cloneBasicBlockAnalysis hook for
130  /// all passes that implement simple analysis interface.
131  void cloneBasicBlockSimpleAnalysis(BasicBlock *From, BasicBlock *To, Loop *L);
132
133  /// deleteSimpleAnalysisValue - Invoke deleteAnalysisValue hook for all passes
134  /// that implement simple analysis interface.
135  void deleteSimpleAnalysisValue(Value *V, Loop *L);
136
137private:
138  std::deque<Loop *> LQ;
139  bool skipThisLoop;
140  bool redoThisLoop;
141  LoopInfo *LI;
142  Loop *CurrentLoop;
143};
144
145} // End llvm namespace
146
147#endif
148