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BBLiveVar.h

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00001 //===-- BBLiveVar.h - Live Variable Analysis for a BasicBlock ---*- C++ -*-===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This is a BasicBlock annotation class that is used by live var analysis to
00011 // hold data flow information for a basic block.
00012 //
00013 //===----------------------------------------------------------------------===//
00014 
00015 #ifndef LIVE_VAR_BB_H
00016 #define LIVE_VAR_BB_H
00017 
00018 #include "llvm/CodeGen/ValueSet.h"
00019 #include "llvm/ADT/hash_map"
00020 
00021 namespace llvm {
00022 
00023 class BasicBlock;
00024 class Value;
00025 class MachineBasicBlock;
00026 
00027 enum LiveVarDebugLevel_t {
00028   LV_DEBUG_None,
00029   LV_DEBUG_Normal,
00030   LV_DEBUG_Instr,
00031   LV_DEBUG_Verbose
00032 };
00033 
00034 extern LiveVarDebugLevel_t DEBUG_LV;
00035 
00036 class BBLiveVar {
00037   const BasicBlock &BB;         // pointer to BasicBlock
00038   const MachineBasicBlock &MBB; // Pointer to MachineBasicBlock
00039   unsigned POID;                // Post-Order ID
00040 
00041   ValueSet DefSet;           // Def set (with no preceding uses) for LV analysis
00042   ValueSet InSet, OutSet;       // In & Out for LV analysis
00043   bool InSetChanged, OutSetChanged;   // set if the InSet/OutSet is modified
00044 
00045                                 // map that contains PredBB -> Phi arguments
00046                                 // coming in on that edge.  such uses have to be
00047                                 // treated differently from ordinary uses.
00048   hash_map<const BasicBlock *, ValueSet> PredToEdgeInSetMap;
00049   
00050   // method to propagate an InSet to OutSet of a predecessor
00051   bool setPropagate(ValueSet *OutSetOfPred, 
00052                     const ValueSet *InSetOfThisBB,
00053                     const BasicBlock *PredBB);
00054 
00055   // To add an operand which is a def
00056   void addDef(const Value *Op); 
00057 
00058   // To add an operand which is a use
00059   void addUse(const Value *Op);
00060 
00061   void calcDefUseSets();         // calculates the Def & Use sets for this BB
00062 public:
00063 
00064   BBLiveVar(const BasicBlock &BB, const MachineBasicBlock &MBB, unsigned POID);
00065 
00066   inline bool isInSetChanged() const  { return InSetChanged; }    
00067   inline bool isOutSetChanged() const { return OutSetChanged; }
00068 
00069   const MachineBasicBlock &getMachineBasicBlock() const { return MBB; }
00070 
00071   inline unsigned getPOId() const { return POID; }
00072 
00073   bool applyTransferFunc();      // calcultes the In in terms of Out 
00074 
00075   // calculates Out set using In sets of the predecessors
00076   bool applyFlowFunc(hash_map<const BasicBlock*, BBLiveVar*> &BBLiveVarInfo);
00077 
00078   inline const ValueSet &getOutSet() const { return OutSet; }
00079   inline       ValueSet &getOutSet()       { return OutSet; }
00080 
00081   inline const ValueSet  &getInSet() const { return InSet; }
00082   inline       ValueSet  &getInSet()       { return InSet; }
00083 
00084   void printAllSets() const;      // for printing Def/In/Out sets
00085   void printInOutSets() const;    // for printing In/Out sets
00086 };
00087 
00088 } // End llvm namespace
00089 
00090 #endif