LoopPass.h revision e4f1a7e8ffbfe48e2c0b9180d8aaef3f64e532ed 
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 {
30
31 public:
32  explicit LoopPass(intptr_t 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  virtual bool runOnFunctionBody (Function &F, LPPassManager &LPM) {
38    return false;
39  }
40
41  // Initialization and finalization hooks.
42  virtual bool doInitialization(Loop *L, LPPassManager &LPM) {
43    return false;
44  }
45
46  // Finalization hook does not supply Loop because at this time
47  // loop nest is completely different.
48  virtual bool doFinalization() { return false; }
49
50  // Check if this pass is suitable for the current LPPassManager, if
51  // available. This pass P is not suitable for a LPPassManager if P
52  // is not preserving higher level analysis info used by other
53  // LPPassManager passes. In such case, pop LPPassManager from the
54  // stack. This will force assignPassManager() to create new
55  // LPPassManger as expected.
56  void preparePassManager(PMStack &PMS);
57
58  /// Assign pass manager to manager this pass
59  virtual void assignPassManager(PMStack &PMS,
60                                 PassManagerType PMT = PMT_LoopPassManager);
61
62  ///  Return what kind of Pass Manager can manage this pass.
63  virtual PassManagerType getPotentialPassManagerType() const {
64    return PMT_LoopPassManager;
65  }
66
67  //===--------------------------------------------------------------------===//
68  /// SimpleAnalysis - Provides simple interface to update analysis info
69  /// maintained by various passes. Note, if required this interface can
70  /// be extracted into a separate abstract class but it would require
71  /// additional use of multiple inheritance in Pass class hierarcy, something
72  /// we are trying to avoid.
73
74  /// Each loop pass can override these simple analysis hooks to update
75  /// desired analysis information.
76  /// cloneBasicBlockAnalysis - Clone analysis info associated with basic block.
77  virtual void cloneBasicBlockAnalysis(BasicBlock *F, BasicBlock *T, Loop *L) {}
78
79  /// deletekAnalysisValue - Delete analysis info associated with value V.
80  virtual void deleteAnalysisValue(Value *V, Loop *L) {}
81};
82
83class LPPassManager : public FunctionPass, public PMDataManager {
84
85public:
86  static char ID;
87  explicit LPPassManager(int Depth);
88
89  /// run - Execute all of the passes scheduled for execution.  Keep track of
90  /// whether any of the passes modifies the module, and if so, return true.
91  bool runOnFunction(Function &F);
92
93  /// Pass Manager itself does not invalidate any analysis info.
94  // LPPassManager needs LoopInfo.
95  void getAnalysisUsage(AnalysisUsage &Info) const;
96
97  virtual const char *getPassName() const {
98    return "Loop Pass Manager";
99  }
100
101  // Print passes managed by this manager
102  void dumpPassStructure(unsigned Offset) {
103    llvm::cerr << std::string(Offset*2, ' ') << "Loop Pass Manager\n";
104    for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
105      Pass *P = getContainedPass(Index);
106      P->dumpPassStructure(Offset + 1);
107      dumpLastUses(P, Offset+1);
108    }
109  }
110
111  Pass *getContainedPass(unsigned N) {
112    assert ( N < PassVector.size() && "Pass number out of range!");
113    Pass *FP = static_cast<Pass *>(PassVector[N]);
114    return FP;
115  }
116
117  virtual PassManagerType getPassManagerType() const {
118    return PMT_LoopPassManager;
119  }
120
121public:
122  // Delete loop from the loop queue and loop nest (LoopInfo).
123  void deleteLoopFromQueue(Loop *L);
124
125  // Inset loop into the loop nest(LoopInfo) and loop queue(LQ).
126  void insertLoop(Loop *L, Loop *ParentLoop);
127
128  // Reoptimize this loop. LPPassManager will re-insert this loop into the
129  // queue. This allows LoopPass to change loop nest for the loop. This
130  // utility may send LPPassManager into infinite loops so use caution.
131  void redoLoop(Loop *L);
132
133  //===--------------------------------------------------------------------===//
134  /// SimpleAnalysis - Provides simple interface to update analysis info
135  /// maintained by various passes. Note, if required this interface can
136  /// be extracted into a separate abstract class but it would require
137  /// additional use of multiple inheritance in Pass class hierarcy, something
138  /// we are trying to avoid.
139
140  /// cloneBasicBlockSimpleAnalysis - Invoke cloneBasicBlockAnalysis hook for
141  /// all passes that implement simple analysis interface.
142  void cloneBasicBlockSimpleAnalysis(BasicBlock *From, BasicBlock *To, Loop *L);
143
144  /// deleteSimpleAnalysisValue - Invoke deleteAnalysisValue hook for all passes
145  /// that implement simple analysis interface.
146  void deleteSimpleAnalysisValue(Value *V, Loop *L);
147private:
148  std::deque<Loop *> LQ;
149  bool skipThisLoop;
150  bool redoThisLoop;
151  LoopInfo *LI;
152  Loop *CurrentLoop;
153};
154
155} // End llvm namespace
156
157#endif
158