include/llvm/Analysis/RegionPass.h

   1 //===- RegionPass.h - RegionPass class --------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file defines the RegionPass class. All region based analysis,
  10 // optimization and transformation passes are derived from RegionPass.
  11 // This class is implemented following the some ideas of the LoopPass.h class.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_ANALYSIS_REGIONPASS_H
  16 #define LLVM_ANALYSIS_REGIONPASS_H
  17
  18 #include "llvm/Analysis/RegionInfo.h"
  19 #include "llvm/IR/Function.h"
  20 #include "llvm/IR/LegacyPassManagers.h"
  21 #include "llvm/Pass.h"
  22 #include <deque>
  23
  24 namespace llvm {
  25
  26 class RGPassManager;
  27 class Function;
  28
  29 //===----------------------------------------------------------------------===//
  30 /// A pass that runs on each Region in a function.
  31 ///
  32 /// RegionPass is managed by RGPassManager.
  33 class RegionPass : public Pass {
  34 public:
  35   explicit RegionPass(char &pid) : Pass(PT_Region, pid) {}
  36
  37   //===--------------------------------------------------------------------===//
  38   /// @name To be implemented by every RegionPass
  39   ///
  40   //@{
  41   /// Run the pass on a specific Region
  42   ///
  43   /// Accessing regions not contained in the current region is not allowed.
  44   ///
  45   /// @param R The region this pass is run on.
  46   /// @param RGM The RegionPassManager that manages this Pass.
  47   ///
  48   /// @return True if the pass modifies this Region.
  49   virtual bool runOnRegion(Region *R, RGPassManager &RGM) = 0;
  50
  51   /// Get a pass to print the LLVM IR in the region.
  52   ///
  53   /// @param O      The output stream to print the Region.
  54   /// @param Banner The banner to separate different printed passes.
  55   ///
  56   /// @return The pass to print the LLVM IR in the region.
  57   Pass *createPrinterPass(raw_ostream &O,
  58                           const std::string &Banner) const override;
  59
  60   using llvm::Pass::doInitialization;
  61   using llvm::Pass::doFinalization;
  62
  63   virtual bool doInitialization(Region *R, RGPassManager &RGM) { return false; }
  64   virtual bool doFinalization() { return false; }
  65   //@}
  66
  67   //===--------------------------------------------------------------------===//
  68   /// @name PassManager API
  69   ///
  70   //@{
  71   void preparePassManager(PMStack &PMS) override;
  72
  73   void assignPassManager(PMStack &PMS,
  74                          PassManagerType PMT = PMT_RegionPassManager) override;
  75
  76   PassManagerType getPotentialPassManagerType() const override {
  77     return PMT_RegionPassManager;
  78   }
  79   //@}
  80
  81 protected:
  82   /// Optional passes call this function to check whether the pass should be
  83   /// skipped. This is the case when optimization bisect is over the limit.
  84   bool skipRegion(Region &R) const;
  85 };
  86
  87 /// The pass manager to schedule RegionPasses.
  88 class RGPassManager : public FunctionPass, public PMDataManager {
  89   std::deque<Region*> RQ;
  90   bool skipThisRegion;
  91   bool redoThisRegion;
  92   RegionInfo *RI;
  93   Region *CurrentRegion;
  94
  95 public:
  96   static char ID;
  97   explicit RGPassManager();
  98
  99   /// Execute all of the passes scheduled for execution.
 100   ///
 101   /// @return True if any of the passes modifies the function.
 102   bool runOnFunction(Function &F) override;
 103
 104   /// Pass Manager itself does not invalidate any analysis info.
 105   /// RGPassManager needs RegionInfo.
 106   void getAnalysisUsage(AnalysisUsage &Info) const override;
 107
 108   StringRef getPassName() const override { return "Region Pass Manager"; }
 109
 110   PMDataManager *getAsPMDataManager() override { return this; }
 111   Pass *getAsPass() override { return this; }
 112
 113   /// Print passes managed by this manager.
 114   void dumpPassStructure(unsigned Offset) override;
 115
 116   /// Get passes contained by this manager.
 117   Pass *getContainedPass(unsigned N) {
 118     assert(N < PassVector.size() && "Pass number out of range!");
 119     Pass *FP = static_cast<Pass *>(PassVector[N]);
 120     return FP;
 121   }
 122
 123   PassManagerType getPassManagerType() const override {
 124     return PMT_RegionPassManager;
 125   }
 126 };
 127
 128 } // End llvm namespace
 129
 130 #endif