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124 lines
4.1 KiB
C++
124 lines
4.1 KiB
C++
//===-- IGNode.h - Represent a node in an interference graph ----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file represents a node in an interference graph.
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//
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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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//
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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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//
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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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//
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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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//===----------------------------------------------------------------------===//
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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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#include <vector>
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namespace llvm {
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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 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 LiveRange *getParentLR() const { return ParentLR; }
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};
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} // End llvm namespace
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#endif
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