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/IR/LegacyPassManagers.h" 20 #include "llvm/Pass.h" 21 #include <deque> 22 23 namespace llvm { 24 25 class LPPassManager; 26 class Function; 27 class PMStack; 28 29 class LoopPass : public Pass { 30 public: 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, 36 const std::string &Banner) const override; 37 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; 41 42 using llvm::Pass::doInitialization; 43 using llvm::Pass::doFinalization; 44 45 // Initialization and finalization hooks. 46 virtual bool doInitialization(Loop *L, LPPassManager &LPM) { 47 return false; 48 } 49 50 // Finalization hook does not supply Loop because at this time 51 // loop nest is completely different. 52 virtual bool doFinalization() { return false; } 53 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; 61 62 /// Assign pass manager to manage this pass 63 void assignPassManager(PMStack &PMS, PassManagerType PMT) override; 64 65 /// Return what kind of Pass Manager can manage this pass. 66 PassManagerType getPotentialPassManagerType() const override { 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 /// 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) {} 89 90 protected: 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; 95 }; 96 97 class LPPassManager : public FunctionPass, public PMDataManager { 98 public: 99 static char ID; 100 explicit LPPassManager(); 101 102 /// 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; 105 106 /// Pass Manager itself does not invalidate any analysis info. 107 // LPPassManager needs LoopInfo. 108 void getAnalysisUsage(AnalysisUsage &Info) const override; 109 110 StringRef getPassName() const override { return "Loop Pass Manager"; } 111 112 PMDataManager *getAsPMDataManager() override { return this; } 113 Pass *getAsPass() override { return this; } 114 115 /// Print passes managed by this manager 116 void dumpPassStructure(unsigned Offset) override; 117 118 LoopPass *getContainedPass(unsigned N) { 119 assert(N < PassVector.size() && "Pass number out of range!"); 120 LoopPass *LP = static_cast<LoopPass *>(PassVector[N]); 121 return LP; 122 } 123 124 PassManagerType getPassManagerType() const override { 125 return PMT_LoopPassManager; 126 } 127 128 public: 129 // Add a new loop into the loop queue. 130 void addLoop(Loop &L); 131 132 // Mark \p L as deleted. 133 void markLoopAsDeleted(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); 149 150 /// Invoke deleteAnalysisLoop hook for all passes that implement simple 151 /// analysis interface. 152 void deleteSimpleAnalysisLoop(Loop *L); 153 154 private: 155 std::deque<Loop *> LQ; 156 LoopInfo *LI; 157 Loop *CurrentLoop; 158 bool CurrentLoopDeleted; 159 }; 160 161 // This pass is required by the LCSSA transformation. It is used inside 162 // LPPassManager to check if current pass preserves LCSSA form, and if it does 163 // pass manager calls lcssa verification for the current loop. 164 struct LCSSAVerificationPass : public FunctionPass { 165 static char ID; 166 LCSSAVerificationPass() : FunctionPass(ID) { 167 initializeLCSSAVerificationPassPass(*PassRegistry::getPassRegistry()); 168 } 169 170 bool runOnFunction(Function &F) override { return false; } 171 172 void getAnalysisUsage(AnalysisUsage &AU) const override { 173 AU.setPreservesAll(); 174 } 175 }; 176 177 } // End llvm namespace 178 179 #endif 180