LoopPass.h revision cbdb7e4b560f77f49f042ea47eac6d4980d8bece 
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_ANALYSIS_LOOPPASS_H
16#define LLVM_ANALYSIS_LOOPPASS_H
17
18#include "llvm/Analysis/LoopInfo.h"
19#include "llvm/Pass.h"
20#include "llvm/PassManagers.h"
21#include <deque>
22
23namespace llvm {
24
25class LPPassManager;
26class Function;
27class PMStack;
28
29class LoopPass : public Pass {
30public:
31  explicit LoopPass(char &pid) : Pass(PT_Loop, pid) {}
32
33  /// getPrinterPass - Get a pass to print the function corresponding
34  /// to a Loop.
35  Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
36
37  // runOnLoop - This method should be implemented by the subclass to perform
38  // whatever action is necessary for the specified Loop.
39  virtual bool runOnLoop(Loop *L, LPPassManager &LPM) = 0;
40
41  using llvm::Pass::doInitialization;
42  using llvm::Pass::doFinalization;
43
44  // Initialization and finalization hooks.
45  virtual bool doInitialization(Loop *L, LPPassManager &LPM) {
46    return false;
47  }
48
49  // Finalization hook does not supply Loop because at this time
50  // loop nest is completely different.
51  virtual bool doFinalization() { return false; }
52
53  // Check if this pass is suitable for the current LPPassManager, if
54  // available. This pass P is not suitable for a LPPassManager if P
55  // is not preserving higher level analysis info used by other
56  // LPPassManager passes. In such case, pop LPPassManager from the
57  // stack. This will force assignPassManager() to create new
58  // LPPassManger as expected.
59  void preparePassManager(PMStack &PMS);
60
61  /// Assign pass manager to manage this pass
62  virtual void assignPassManager(PMStack &PMS,
63                                 PassManagerType PMT);
64
65  ///  Return what kind of Pass Manager can manage this pass.
66  virtual PassManagerType getPotentialPassManagerType() const {
67    return PMT_LoopPassManager;
68  }
69
70  //===--------------------------------------------------------------------===//
71  /// SimpleAnalysis - Provides simple interface to update analysis info
72  /// maintained by various passes. Note, if required this interface can
73  /// be extracted into a separate abstract class but it would require
74  /// additional use of multiple inheritance in Pass class hierarchy, something
75  /// we are trying to avoid.
76
77  /// Each loop pass can override these simple analysis hooks to update
78  /// desired analysis information.
79  /// cloneBasicBlockAnalysis - Clone analysis info associated with basic block.
80  virtual void cloneBasicBlockAnalysis(BasicBlock *F, BasicBlock *T, Loop *L) {}
81
82  /// deleteAnalysisValue - Delete analysis info associated with value V.
83  virtual void deleteAnalysisValue(Value *V, Loop *L) {}
84};
85
86class LPPassManager : public FunctionPass, public PMDataManager {
87public:
88  static char ID;
89  explicit LPPassManager();
90
91  /// run - Execute all of the passes scheduled for execution.  Keep track of
92  /// whether any of the passes modifies the module, and if so, return true.
93  bool runOnFunction(Function &F);
94
95  /// Pass Manager itself does not invalidate any analysis info.
96  // LPPassManager needs LoopInfo.
97  void getAnalysisUsage(AnalysisUsage &Info) const;
98
99  virtual const char *getPassName() const {
100    return "Loop Pass Manager";
101  }
102
103  virtual PMDataManager *getAsPMDataManager() { return this; }
104  virtual Pass *getAsPass() { return this; }
105
106  /// Print passes managed by this manager
107  void dumpPassStructure(unsigned Offset);
108
109  LoopPass *getContainedPass(unsigned N) {
110    assert(N < PassVector.size() && "Pass number out of range!");
111    LoopPass *LP = static_cast<LoopPass *>(PassVector[N]);
112    return LP;
113  }
114
115  virtual PassManagerType getPassManagerType() const {
116    return PMT_LoopPassManager;
117  }
118
119public:
120  // Delete loop from the loop queue and loop nest (LoopInfo).
121  void deleteLoopFromQueue(Loop *L);
122
123  // Insert loop into the loop queue and add it as a child of the
124  // given parent.
125  void insertLoop(Loop *L, Loop *ParentLoop);
126
127  // Insert a loop into the loop queue.
128  void insertLoopIntoQueue(Loop *L);
129
130  // Reoptimize this loop. LPPassManager will re-insert this loop into the
131  // queue. This allows LoopPass to change loop nest for the loop. This
132  // utility may send LPPassManager into infinite loops so use caution.
133  void redoLoop(Loop *L);
134
135  //===--------------------------------------------------------------------===//
136  /// SimpleAnalysis - Provides simple interface to update analysis info
137  /// maintained by various passes. Note, if required this interface can
138  /// be extracted into a separate abstract class but it would require
139  /// additional use of multiple inheritance in Pass class hierarchy, something
140  /// we are trying to avoid.
141
142  /// cloneBasicBlockSimpleAnalysis - Invoke cloneBasicBlockAnalysis hook for
143  /// all passes that implement simple analysis interface.
144  void cloneBasicBlockSimpleAnalysis(BasicBlock *From, BasicBlock *To, Loop *L);
145
146  /// deleteSimpleAnalysisValue - Invoke deleteAnalysisValue hook for all passes
147  /// that implement simple analysis interface.
148  void deleteSimpleAnalysisValue(Value *V, Loop *L);
149
150private:
151  std::deque<Loop *> LQ;
152  bool skipThisLoop;
153  bool redoThisLoop;
154  LoopInfo *LI;
155  Loop *CurrentLoop;
156};
157
158} // End llvm namespace
159
160#endif
161