LoopPass.h revision 22033be445aea2a28e8d11d2e2453382a1515f12 
1//===- LoopPass.h - LoopPass class ----------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by Devang Patel and is distributed under
6// the University of Illinois Open Source 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 Loop;
27class Function;
28
29class LoopPass : public Pass {
30
31 public:
32  // runOnLoop - THis method should be implemented by the subclass to perform
33  // whatever action is necessary for the specfied Loop.
34  virtual bool runOnLoop (Loop *L, LPPassManager &LPM) = 0;
35  virtual bool runOnFunctionBody (Function &F, LPPassManager &LPM) {
36    return false;
37  }
38
39  // Initialization and finalization hooks.
40  virtual bool doInitialization(Loop *L, LPPassManager &LPM) {
41    return false;
42  }
43
44  // Finalization hook does not supply Loop because at this time
45  // loop nest is completely different.
46  virtual bool doFinalization() { return false; }
47
48  // Check if this pass is suitable for the current LPPassManager, if
49  // available. This pass P is not suitable for a LPPassManager if P
50  // is not preserving higher level analysis info used by other
51  // LPPassManager passes. In such case, pop LPPassManager from the
52  // stack. This will force assignPassManager() to create new
53  // LPPassManger as expected.
54  void preparePassManager(PMStack &PMS);
55
56  /// Assign pass manager to manager this pass
57  virtual void assignPassManager(PMStack &PMS,
58				 PassManagerType PMT = PMT_LoopPassManager);
59
60};
61
62class LPPassManager : public FunctionPass, public PMDataManager {
63
64public:
65  LPPassManager(int Depth);
66
67  /// run - Execute all of the passes scheduled for execution.  Keep track of
68  /// whether any of the passes modifies the module, and if so, return true.
69  bool runOnFunction(Function &F);
70
71  /// Pass Manager itself does not invalidate any analysis info.
72  void getAnalysisUsage(AnalysisUsage &Info) const {
73    // LPPassManager needs LoopInfo. In the long term LoopInfo class will
74    // be consumed by LPPassManager.
75    Info.addRequired<LoopInfo>();
76    Info.setPreservesAll();
77  }
78
79  virtual const char *getPassName() const {
80    return "Loop Pass Manager";
81  }
82
83  // Print passes managed by this manager
84  void dumpPassStructure(unsigned Offset) {
85    llvm::cerr << std::string(Offset*2, ' ') << "Loop Pass Manager\n";
86    for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
87      Pass *P = getContainedPass(Index);
88      P->dumpPassStructure(Offset + 1);
89      dumpLastUses(P, Offset+1);
90    }
91  }
92
93  Pass *getContainedPass(unsigned N) {
94    assert ( N < PassVector.size() && "Pass number out of range!");
95    Pass *FP = static_cast<Pass *>(PassVector[N]);
96    return FP;
97  }
98
99  virtual PassManagerType getPassManagerType() const {
100    return PMT_LoopPassManager;
101  }
102
103public:
104  // Delete loop from the loop queue. This is used by Loop pass to inform
105  // Loop Pass Manager that it should skip rest of the passes for this loop.
106  void deleteLoopFromQueue(Loop *L);
107
108  // Reoptimize this loop. LPPassManager will re-insert this loop into the
109  // queue. This allows LoopPass to change loop nest for the loop. This
110  // utility may send LPPassManager into infinite loops so use caution.
111  void redoLoop(Loop *L);
112private:
113  std::deque<Loop *> LQ;
114  bool skipThisLoop;
115  bool redoThisLoop;
116};
117
118} // End llvm namespace
119
120#endif
121