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			125 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			125 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/* Title:   IGNode.h                      -*- C++ -*-
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   Author:  Ruchira Sasanka
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   Date:    July 25, 01
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   Purpose: Represents a node in an interference graph. 
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   Notes:
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   For efficiency, the AdjList is updated only once - ie. we can add but not
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   remove nodes from AdjList. 
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   The removal of nodes from IG is simulated by decrementing the CurDegree.
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   If this node is put on stack (that is removed from IG), the CurDegree of all
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   the neighbors are decremented and this node is marked OnStack. Hence
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   the effective neighbors in the AdjList are the ones that do not have the
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   OnStack flag set (therefore, they are in the IG).
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   The methods that modify/use the CurDegree must be called only
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   after all modifications to the IG are over (i.e., all neighbors are fixed).
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   The vector representation is the most efficient one for adj list.
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   Though nodes are removed when coalescing is done, we access it in sequence
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   for far many times when coloring (colorNode()).
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*/
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#ifndef IGNODE_H
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#define IGNODE_H
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#include "LiveRange.h"
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class RegClass;
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//----------------------------------------------------------------------------
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// Class IGNode
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//
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// Represents a node in an interference graph.
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//----------------------------------------------------------------------------
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class IGNode {
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  const unsigned Index;         // index within IGNodeList 
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  bool OnStack;                 // this has been pushed on to stack for coloring
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  std::vector<IGNode *> AdjList;// adjacency list for this live range
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  int CurDegree;     
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  //
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  // set by InterferenceGraph::setCurDegreeOfIGNodes() after calculating
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  // all adjacency lists.
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  // Decremented when a neighbor is pushed on to the stack. 
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  // After that, never incremented/set again nor used.
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  LiveRange *const ParentLR;
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public:
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  IGNode(LiveRange *LR, unsigned index) : Index(index), ParentLR(LR) {
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    OnStack = false;
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    CurDegree = -1;
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    ParentLR->setUserIGNode(this);
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  }
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  inline unsigned int getIndex() const { return Index; }
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  // adjLists must be updated only once.  However, the CurDegree can be changed
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  //
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  inline void addAdjIGNode(IGNode *AdjNode) { AdjList.push_back(AdjNode);  } 
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  inline IGNode *getAdjIGNode(unsigned ind) const 
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    { assert ( ind < AdjList.size()); return AdjList[ind]; }
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  // delete a node in AdjList - node must be in the list
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  // should not be called often
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  //
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  void delAdjIGNode(const IGNode *Node); 
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  inline unsigned getNumOfNeighbors() const { return AdjList.size(); }
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  // Get the number of unique neighbors if these two nodes are merged
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  unsigned getCombinedDegree(const IGNode* otherNode) const;
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  inline bool isOnStack() const { return OnStack; }
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  // remove form IG and pushes on to stack (reduce the degree of neighbors)
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  //
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  void pushOnStack(); 
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  // CurDegree is the effective number of neighbors when neighbors are
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  // pushed on to the stack during the coloring phase. Must be called
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  // after all modifications to the IG are over (i.e., all neighbors are
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  // fixed).
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  //
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  inline void setCurDegree() {
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    assert(CurDegree == -1);
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    CurDegree = AdjList.size();
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  }
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  inline int getCurDegree() const { return CurDegree; }
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  // called when a neigh is pushed on to stack
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  //
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  inline void decCurDegree() { assert(CurDegree > 0); --CurDegree; }
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  // The following methods call the methods in ParentLR
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  // They are added to this class for convenience
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  // If many of these are called within a single scope,
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  // consider calling the methods directly on LR
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  inline void setRegClass(RegClass *RC) { ParentLR->setRegClass(RC);  }
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  inline RegClass *getRegClass() const { return ParentLR->getRegClass(); }
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  inline bool hasColor() const { return ParentLR->hasColor();  }
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  inline unsigned int getColor() const { return ParentLR->getColor();  }
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  inline void setColor(unsigned Col) { ParentLR->setColor(Col);  }
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  inline void markForSpill() { ParentLR->markForSpill(); }
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  inline void markForSaveAcrossCalls() { ParentLR->markForSaveAcrossCalls();  }
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  inline unsigned int isCallInterference() const 
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  { return ParentLR->isCallInterference(); } 
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  inline LiveRange *getParentLR() const { return ParentLR; }
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};
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#endif
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