Home | History | Annotate | Download | only in Analysis 
      1 //===- RegionPass.h - RegionPass class --------------------------*- C++ -*-===//
      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 the RegionPass class. All region based analysis,
     11 // optimization and transformation passes are derived from RegionPass.
     12 // This class is implemented following the some ideas of the LoopPass.h class.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #ifndef LLVM_ANALYSIS_REGIONPASS_H
     17 #define LLVM_ANALYSIS_REGIONPASS_H
     18 
     19 #include "llvm/Analysis/RegionInfo.h"
     20 #include "llvm/IR/Function.h"
     21 #include "llvm/IR/LegacyPassManagers.h"
     22 #include "llvm/Pass.h"
     23 #include <deque>
     24 
     25 namespace llvm {
     26 
     27 class RGPassManager;
     28 class Function;
     29 
     30 //===----------------------------------------------------------------------===//
     31 /// @brief A pass that runs on each Region in a function.
     32 ///
     33 /// RegionPass is managed by RGPassManager.
     34 class RegionPass : public Pass {
     35 public:
     36   explicit RegionPass(char &pid) : Pass(PT_Region, pid) {}
     37 
     38   //===--------------------------------------------------------------------===//
     39   /// @name To be implemented by every RegionPass
     40   ///
     41   //@{
     42   /// @brief Run the pass on a specific Region
     43   ///
     44   /// Accessing regions not contained in the current region is not allowed.
     45   ///
     46   /// @param R The region this pass is run on.
     47   /// @param RGM The RegionPassManager that manages this Pass.
     48   ///
     49   /// @return True if the pass modifies this Region.
     50   virtual bool runOnRegion(Region *R, RGPassManager &RGM) = 0;
     51 
     52   /// @brief Get a pass to print the LLVM IR in the region.
     53   ///
     54   /// @param O      The output stream to print the Region.
     55   /// @param Banner The banner to separate different printed passes.
     56   ///
     57   /// @return The pass to print the LLVM IR in the region.
     58   Pass *createPrinterPass(raw_ostream &O,
     59                           const std::string &Banner) const override;
     60 
     61   using llvm::Pass::doInitialization;
     62   using llvm::Pass::doFinalization;
     63 
     64   virtual bool doInitialization(Region *R, RGPassManager &RGM) { return false; }
     65   virtual bool doFinalization() { return false; }
     66   //@}
     67 
     68   //===--------------------------------------------------------------------===//
     69   /// @name PassManager API
     70   ///
     71   //@{
     72   void preparePassManager(PMStack &PMS) override;
     73 
     74   void assignPassManager(PMStack &PMS,
     75                          PassManagerType PMT = PMT_RegionPassManager) override;
     76 
     77   PassManagerType getPotentialPassManagerType() const override {
     78     return PMT_RegionPassManager;
     79   }
     80   //@}
     81 
     82 protected:
     83   /// Optional passes call this function to check whether the pass should be
     84   /// skipped. This is the case when optimization bisect is over the limit.
     85   bool skipRegion(Region &R) const;
     86 };
     87 
     88 /// @brief The pass manager to schedule RegionPasses.
     89 class RGPassManager : public FunctionPass, public PMDataManager {
     90   std::deque<Region*> RQ;
     91   bool skipThisRegion;
     92   bool redoThisRegion;
     93   RegionInfo *RI;
     94   Region *CurrentRegion;
     95 
     96 public:
     97   static char ID;
     98   explicit RGPassManager();
     99 
    100   /// @brief Execute all of the passes scheduled for execution.
    101   ///
    102   /// @return True if any of the passes modifies the function.
    103   bool runOnFunction(Function &F) override;
    104 
    105   /// Pass Manager itself does not invalidate any analysis info.
    106   /// RGPassManager needs RegionInfo.
    107   void getAnalysisUsage(AnalysisUsage &Info) const override;
    108 
    109   StringRef getPassName() const override { return "Region Pass Manager"; }
    110 
    111   PMDataManager *getAsPMDataManager() override { return this; }
    112   Pass *getAsPass() override { return this; }
    113 
    114   /// @brief Print passes managed by this manager.
    115   void dumpPassStructure(unsigned Offset) override;
    116 
    117   /// @brief Get passes contained by this manager.
    118   Pass *getContainedPass(unsigned N) {
    119     assert(N < PassVector.size() && "Pass number out of range!");
    120     Pass *FP = static_cast<Pass *>(PassVector[N]);
    121     return FP;
    122   }
    123 
    124   PassManagerType getPassManagerType() const override {
    125     return PMT_RegionPassManager;
    126   }
    127 };
    128 
    129 } // End llvm namespace
    130 
    131 #endif
    132