1 //===- RegionPass.h - RegionPass 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 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:
RegionPass(char & pid)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, const std::string &Banner) const;
59 
60   using llvm::Pass::doInitialization;
61   using llvm::Pass::doFinalization;
62 
doInitialization(Region * R,RGPassManager & RGM)63   virtual bool doInitialization(Region *R, RGPassManager &RGM) { return false; }
doFinalization()64   virtual bool doFinalization() { return false; }
65   //@}
66 
67   //===--------------------------------------------------------------------===//
68   /// @name PassManager API
69   ///
70   //@{
71   void preparePassManager(PMStack &PMS);
72 
73   virtual void assignPassManager(PMStack &PMS,
74     PassManagerType PMT = PMT_RegionPassManager);
75 
getPotentialPassManagerType()76   virtual PassManagerType getPotentialPassManagerType() const {
77     return PMT_RegionPassManager;
78   }
79   //@}
80 };
81 
82 /// @brief The pass manager to schedule RegionPasses.
83 class RGPassManager : public FunctionPass, public PMDataManager {
84   std::deque<Region*> RQ;
85   bool skipThisRegion;
86   bool redoThisRegion;
87   RegionInfo *RI;
88   Region *CurrentRegion;
89 
90 public:
91   static char ID;
92   explicit RGPassManager();
93 
94   /// @brief Execute all of the passes scheduled for execution.
95   ///
96   /// @return True if any of the passes modifies the function.
97   bool runOnFunction(Function &F);
98 
99   /// Pass Manager itself does not invalidate any analysis info.
100   /// RGPassManager needs RegionInfo.
101   void getAnalysisUsage(AnalysisUsage &Info) const;
102 
getPassName()103   virtual const char *getPassName() const {
104     return "Region Pass Manager";
105   }
106 
getAsPMDataManager()107   virtual PMDataManager *getAsPMDataManager() { return this; }
getAsPass()108   virtual Pass *getAsPass() { return this; }
109 
110   /// @brief Print passes managed by this manager.
111   void dumpPassStructure(unsigned Offset);
112 
113   /// @brief Get passes contained by this manager.
getContainedPass(unsigned N)114   Pass *getContainedPass(unsigned N) {
115     assert(N < PassVector.size() && "Pass number out of range!");
116     Pass *FP = static_cast<Pass *>(PassVector[N]);
117     return FP;
118   }
119 
getPassManagerType()120   virtual PassManagerType getPassManagerType() const {
121     return PMT_RegionPassManager;
122   }
123 };
124 
125 } // End llvm namespace
126 
127 #endif
128