1 //===- LoopPass.h - LoopPass class ----------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines LoopPass class. All loop optimization
11 // and transformation passes are derived from LoopPass.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ANALYSIS_LOOPPASS_H
16 #define LLVM_ANALYSIS_LOOPPASS_H
18 #include "llvm/Analysis/LoopInfo.h"
19 #include "llvm/IR/LegacyPassManagers.h"
20 #include "llvm/Pass.h"
29 class LoopPass : public Pass {
31 explicit LoopPass(char &pid) : Pass(PT_Loop, pid) {}
33 /// getPrinterPass - Get a pass to print the function corresponding
35 Pass *createPrinterPass(raw_ostream &O,
36 const std::string &Banner) const override;
38 // runOnLoop - This method should be implemented by the subclass to perform
39 // whatever action is necessary for the specified Loop.
40 virtual bool runOnLoop(Loop *L, LPPassManager &LPM) = 0;
42 using llvm::Pass::doInitialization;
43 using llvm::Pass::doFinalization;
45 // Initialization and finalization hooks.
46 virtual bool doInitialization(Loop *L, LPPassManager &LPM) {
50 // Finalization hook does not supply Loop because at this time
51 // loop nest is completely different.
52 virtual bool doFinalization() { return false; }
54 // Check if this pass is suitable for the current LPPassManager, if
55 // available. This pass P is not suitable for a LPPassManager if P
56 // is not preserving higher level analysis info used by other
57 // LPPassManager passes. In such case, pop LPPassManager from the
58 // stack. This will force assignPassManager() to create new
59 // LPPassManger as expected.
60 void preparePassManager(PMStack &PMS) override;
62 /// Assign pass manager to manage this pass
63 void assignPassManager(PMStack &PMS, PassManagerType PMT) override;
65 /// Return what kind of Pass Manager can manage this pass.
66 PassManagerType getPotentialPassManagerType() const override {
67 return PMT_LoopPassManager;
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.
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) {}
82 /// deleteAnalysisValue - Delete analysis info associated with value V.
83 virtual void deleteAnalysisValue(Value *V, Loop *L) {}
85 /// Delete analysis info associated with Loop L.
86 /// Called to notify a Pass that a loop has been deleted and any
87 /// associated analysis values can be deleted.
88 virtual void deleteAnalysisLoop(Loop *L) {}
91 /// Optional passes call this function to check whether the pass should be
92 /// skipped. This is the case when Attribute::OptimizeNone is set or when
93 /// optimization bisect is over the limit.
94 bool skipLoop(const Loop *L) const;
97 class LPPassManager : public FunctionPass, public PMDataManager {
100 explicit LPPassManager();
102 /// run - Execute all of the passes scheduled for execution. Keep track of
103 /// whether any of the passes modifies the module, and if so, return true.
104 bool runOnFunction(Function &F) override;
106 /// Pass Manager itself does not invalidate any analysis info.
107 // LPPassManager needs LoopInfo.
108 void getAnalysisUsage(AnalysisUsage &Info) const override;
110 StringRef getPassName() const override { return "Loop Pass Manager"; }
112 PMDataManager *getAsPMDataManager() override { return this; }
113 Pass *getAsPass() override { return this; }
115 /// Print passes managed by this manager
116 void dumpPassStructure(unsigned Offset) override;
118 LoopPass *getContainedPass(unsigned N) {
119 assert(N < PassVector.size() && "Pass number out of range!");
120 LoopPass *LP = static_cast<LoopPass *>(PassVector[N]);
124 PassManagerType getPassManagerType() const override {
125 return PMT_LoopPassManager;
129 // Add a new loop into the loop queue.
130 void addLoop(Loop &L);
132 //===--------------------------------------------------------------------===//
133 /// SimpleAnalysis - Provides simple interface to update analysis info
134 /// maintained by various passes. Note, if required this interface can
135 /// be extracted into a separate abstract class but it would require
136 /// additional use of multiple inheritance in Pass class hierarchy, something
137 /// we are trying to avoid.
139 /// cloneBasicBlockSimpleAnalysis - Invoke cloneBasicBlockAnalysis hook for
140 /// all passes that implement simple analysis interface.
141 void cloneBasicBlockSimpleAnalysis(BasicBlock *From, BasicBlock *To, Loop *L);
143 /// deleteSimpleAnalysisValue - Invoke deleteAnalysisValue hook for all passes
144 /// that implement simple analysis interface.
145 void deleteSimpleAnalysisValue(Value *V, Loop *L);
147 /// Invoke deleteAnalysisLoop hook for all passes that implement simple
148 /// analysis interface.
149 void deleteSimpleAnalysisLoop(Loop *L);
152 std::deque<Loop *> LQ;
157 // This pass is required by the LCSSA transformation. It is used inside
158 // LPPassManager to check if current pass preserves LCSSA form, and if it does
159 // pass manager calls lcssa verification for the current loop.
160 struct LCSSAVerificationPass : public FunctionPass {
162 LCSSAVerificationPass() : FunctionPass(ID) {
163 initializeLCSSAVerificationPassPass(*PassRegistry::getPassRegistry());
166 bool runOnFunction(Function &F) override { return false; }
168 void getAnalysisUsage(AnalysisUsage &AU) const override {
169 AU.setPreservesAll();
173 } // End llvm namespace