mirror of
https://github.com/c64scene-ar/llvm-6502.git
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d0f166a486
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5204 91177308-0d34-0410-b5e6-96231b3b80d8
268 lines
8.1 KiB
C++
268 lines
8.1 KiB
C++
//===-- RegClass.cpp -----------------------------------------------------===//
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//
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// class RegClass for coloring-based register allocation for LLVM.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/RegClass.h"
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#include "llvm/CodeGen/RegAllocCommon.h"
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#include "llvm/CodeGen/IGNode.h"
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using std::cerr;
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//----------------------------------------------------------------------------
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// This constructor inits IG. The actual matrix is created by a call to
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// createInterferenceGraph() above.
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//----------------------------------------------------------------------------
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RegClass::RegClass(const Function *M,
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const TargetRegClassInfo *Mrc,
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const ReservedColorListType *RCL)
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: Meth(M), MRC(Mrc), RegClassID( Mrc->getRegClassID() ),
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IG(this), IGNodeStack(), ReservedColorList(RCL) {
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if( DEBUG_RA >= RA_DEBUG_Interference)
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cerr << "Created Reg Class: " << RegClassID << "\n";
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IsColorUsedArr.resize(Mrc->getNumOfAllRegs());
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}
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//----------------------------------------------------------------------------
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// Main entry point for coloring a register class.
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//----------------------------------------------------------------------------
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void RegClass::colorAllRegs()
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{
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if(DEBUG_RA >= RA_DEBUG_Coloring)
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cerr << "Coloring IG of reg class " << RegClassID << " ...\n";
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// pre-color IGNodes
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pushAllIGNodes(); // push all IG Nodes
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unsigned int StackSize = IGNodeStack.size();
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IGNode *CurIGNode;
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// for all LRs on stack
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for( unsigned int IGN=0; IGN < StackSize; IGN++) {
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CurIGNode = IGNodeStack.top(); // pop the IGNode on top of stack
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IGNodeStack.pop();
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colorIGNode (CurIGNode); // color it
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}
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}
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//----------------------------------------------------------------------------
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// The method for pushing all IGNodes on to the stack.
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//----------------------------------------------------------------------------
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void RegClass::pushAllIGNodes()
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{
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bool NeedMoreSpills;
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IG.setCurDegreeOfIGNodes(); // calculate degree of IGNodes
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// push non-constrained IGNodes
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bool PushedAll = pushUnconstrainedIGNodes();
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if( DEBUG_RA >= RA_DEBUG_Coloring) {
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cerr << " Puhsed all-unconstrained IGNodes. ";
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if( PushedAll ) cerr << " No constrained nodes left.";
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cerr << "\n";
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}
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if( PushedAll ) // if NO constrained nodes left
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return;
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// now, we have constrained nodes. So, push one of them (the one with min
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// spill cost) and try to push the others as unConstrained nodes.
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// Repeat this.
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do {
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//get node with min spill cost
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//
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IGNode *IGNodeSpill = getIGNodeWithMinSpillCost();
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// push that node on to stack
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//
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IGNodeStack.push(IGNodeSpill);
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// set its OnStack flag and decrement degree of neighs
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//
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IGNodeSpill->pushOnStack();
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// now push NON-constrined ones, if any
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//
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NeedMoreSpills = !pushUnconstrainedIGNodes();
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if (DEBUG_RA >= RA_DEBUG_Coloring)
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cerr << "\nConstrained IG Node found !@!" << IGNodeSpill->getIndex();
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} while(NeedMoreSpills); // repeat until we have pushed all
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}
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//--------------------------------------------------------------------------
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// This method goes thru all IG nodes in the IGNodeList of an IG of a
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// register class and push any unconstrained IG node left (that is not
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// already pushed)
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//--------------------------------------------------------------------------
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bool RegClass::pushUnconstrainedIGNodes()
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{
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// # of LRs for this reg class
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unsigned int IGNodeListSize = IG.getIGNodeList().size();
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bool pushedall = true;
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// a pass over IGNodeList
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for( unsigned i =0; i < IGNodeListSize; i++) {
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// get IGNode i from IGNodeList
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IGNode *IGNode = IG.getIGNodeList()[i];
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if( !IGNode ) // can be null due to merging
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continue;
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// if already pushed on stack, continue. This can happen since this
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// method can be called repeatedly until all constrained nodes are
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// pushed
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if( IGNode->isOnStack() )
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continue;
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// if the degree of IGNode is lower
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if( (unsigned) IGNode->getCurDegree() < MRC->getNumOfAvailRegs() ) {
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IGNodeStack.push( IGNode ); // push IGNode on to the stack
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IGNode->pushOnStack(); // set OnStack and dec deg of neighs
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if (DEBUG_RA >= RA_DEBUG_Coloring) {
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cerr << " pushed un-constrained IGNode " << IGNode->getIndex() ;
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cerr << " on to stack\n";
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}
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}
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else pushedall = false; // we didn't push all live ranges
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} // for
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// returns true if we pushed all live ranges - else false
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return pushedall;
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}
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//----------------------------------------------------------------------------
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// Get the IGNode withe the minimum spill cost
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//----------------------------------------------------------------------------
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IGNode * RegClass::getIGNodeWithMinSpillCost()
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{
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unsigned int IGNodeListSize = IG.getIGNodeList().size();
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double MinSpillCost = 0;
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IGNode *MinCostIGNode = NULL;
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bool isFirstNode = true;
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// pass over IGNodeList to find the IGNode with minimum spill cost
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// among all IGNodes that are not yet pushed on to the stack
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//
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for( unsigned int i =0; i < IGNodeListSize; i++) {
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IGNode *IGNode = IG.getIGNodeList()[i];
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if( ! IGNode ) // can be null due to merging
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continue;
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if( ! IGNode->isOnStack() ) {
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double SpillCost = (double) IGNode->getParentLR()->getSpillCost() /
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(double) (IGNode->getCurDegree() + 1);
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if( isFirstNode ) { // for the first IG node
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MinSpillCost = SpillCost;
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MinCostIGNode = IGNode;
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isFirstNode = false;
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}
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else if( MinSpillCost > SpillCost) {
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MinSpillCost = SpillCost;
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MinCostIGNode = IGNode;
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}
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}
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}
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assert( MinCostIGNode && "No IGNode to spill");
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return MinCostIGNode;
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}
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//----------------------------------------------------------------------------
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// Color the IGNode using the machine specific code.
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//----------------------------------------------------------------------------
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void RegClass::colorIGNode(IGNode *const Node)
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{
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if( ! Node->hasColor() ) { // not colored as an arg etc.
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// init all elements of to IsColorUsedAr false;
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//
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for (unsigned i=0; i < MRC->getNumOfAllRegs(); i++)
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IsColorUsedArr[i] = false;
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// init all reserved_regs to true - we can't use them
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//
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for( unsigned i=0; i < ReservedColorList->size() ; i++) {
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IsColorUsedArr[(*ReservedColorList)[i]] = true;
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}
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// initialize all colors used by neighbors of this node to true
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LiveRange *LR = Node->getParentLR();
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unsigned NumNeighbors = Node->getNumOfNeighbors();
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for (unsigned n=0; n < NumNeighbors; n++) {
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IGNode *NeighIGNode = Node->getAdjIGNode(n);
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LiveRange *NeighLR = NeighIGNode->getParentLR();
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if (NeighLR->hasColor()) { // if has a color
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IsColorUsedArr[NeighLR->getColor()] = true; // mark color as used
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} else if (NeighLR->hasSuggestedColor() &&
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NeighLR->isSuggestedColorUsable()) {
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// this color is suggested for the neighbour, so don't use it
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IsColorUsedArr[NeighLR->getSuggestedColor()] = true;
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}
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}
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// call the target specific code for coloring
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//
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MRC->colorIGNode(Node, IsColorUsedArr);
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}
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else {
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if( DEBUG_RA >= RA_DEBUG_Coloring) {
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cerr << " Node " << Node->getIndex();
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cerr << " already colored with color " << Node->getColor() << "\n";
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}
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}
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if( !Node->hasColor() ) {
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if( DEBUG_RA >= RA_DEBUG_Coloring) {
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cerr << " Node " << Node->getIndex();
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cerr << " - could not find a color (needs spilling)\n";
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}
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}
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}
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void RegClass::printIGNodeList() const {
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std::cerr << "IG Nodes for Register Class " << RegClassID << ":" << "\n";
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IG.printIGNodeList();
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}
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void RegClass::printIG() {
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std::cerr << "IG for Register Class " << RegClassID << ":" << "\n";
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IG.printIG();
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}
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