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#include "llvm/CodeGen/RegClass.h"
//----------------------------------------------------------------------------
// This constructor inits IG. The actual matrix is created by a call to
// createInterferenceGraph() above.
//----------------------------------------------------------------------------
RegClass::RegClass(const Method *const M,
const MachineRegClassInfo *const Mrc,
const ReservedColorListType *const RCL)
: Meth(M), MRC(Mrc), RegClassID( Mrc->getRegClassID() ),
IG(this), IGNodeStack(), ReservedColorList(RCL) {
if( DEBUG_RA)
cout << "Created Reg Class: " << RegClassID << endl;
IsColorUsedArr = new bool[ Mrc->getNumOfAllRegs() ];
}
//----------------------------------------------------------------------------
// Main entry point for coloring a register class.
//----------------------------------------------------------------------------
void RegClass::colorAllRegs()
{
if(DEBUG_RA) cout << "Coloring IG of reg class " << RegClassID << " ...\n";
// pre-color IGNodes
pushAllIGNodes(); // push all IG Nodes
unsigned int StackSize = IGNodeStack.size();
IGNode *CurIGNode;
// for all LRs on stack
for( unsigned int IGN=0; IGN < StackSize; IGN++) {
CurIGNode = IGNodeStack.top(); // pop the IGNode on top of stack
IGNodeStack.pop();
colorIGNode (CurIGNode); // color it
}
}
//----------------------------------------------------------------------------
// The method for pushing all IGNodes on to the stack.
//----------------------------------------------------------------------------
void RegClass::pushAllIGNodes()
{
bool NeedMoreSpills;
IG.setCurDegreeOfIGNodes(); // calculate degree of IGNodes
// push non-constrained IGNodes
bool PushedAll = pushUnconstrainedIGNodes();
if( DEBUG_RA) {
cout << " Puhsed all-unconstrained IGNodes. ";
if( PushedAll ) cout << " No constrained nodes left.";
cout << endl;
}
if( PushedAll ) // if NO constrained nodes left
return;
// now, we have constrained nodes. So, push one of them (the one with min
// spill cost) and try to push the others as unConstrained nodes.
// Repeat this.
do{
//get node with min spill cost
//
IGNode *IGNodeSpill = getIGNodeWithMinSpillCost();
// push that node on to stack
//
IGNodeStack.push( IGNodeSpill );
// set its OnStack flag and decrement degree of neighs
//
IGNodeSpill->pushOnStack();
// now push NON-constrined ones, if any
//
NeedMoreSpills = ! pushUnconstrainedIGNodes();
cerr << "\nConstrained IG Node found !@!" << IGNodeSpill->getIndex();
} while( NeedMoreSpills ); // repeat until we have pushed all
}
//--------------------------------------------------------------------------
// This method goes thru all IG nodes in the IGNodeList of an IG of a
// register class and push any unconstrained IG node left (that is not
// already pushed)
//--------------------------------------------------------------------------
bool RegClass::pushUnconstrainedIGNodes()
{
// # of LRs for this reg class
unsigned int IGNodeListSize = IG.getIGNodeList().size();
bool pushedall = true;
// a pass over IGNodeList
for( unsigned i =0; i < IGNodeListSize; i++) {
// get IGNode i from IGNodeList
IGNode *IGNode = IG.getIGNodeList()[i];
if( !IGNode ) // can be null due to merging
continue;
// if already pushed on stack, continue. This can happen since this
// method can be called repeatedly until all constrained nodes are
// pushed
if( IGNode->isOnStack() )
continue;
// if the degree of IGNode is lower
if( (unsigned) IGNode->getCurDegree() < MRC->getNumOfAvailRegs() ) {
IGNodeStack.push( IGNode ); // push IGNode on to the stack
IGNode->pushOnStack(); // set OnStack and dec deg of neighs
if (DEBUG_RA > 1) {
cout << " pushed un-constrained IGNode " << IGNode->getIndex() ;
cout << " on to stack" << endl;
}
}
else pushedall = false; // we didn't push all live ranges
} // for
// returns true if we pushed all live ranges - else false
return pushedall;
}
//----------------------------------------------------------------------------
// Get the IGNode withe the minimum spill cost
//----------------------------------------------------------------------------
IGNode * RegClass::getIGNodeWithMinSpillCost()
{
unsigned int IGNodeListSize = IG.getIGNodeList().size();
double MinSpillCost;
IGNode *MinCostIGNode = NULL;
bool isFirstNode = true;
// pass over IGNodeList to find the IGNode with minimum spill cost
// among all IGNodes that are not yet pushed on to the stack
//
for( unsigned int i =0; i < IGNodeListSize; i++) {
IGNode *IGNode = IG.getIGNodeList()[i];
if( ! IGNode ) // can be null due to merging
continue;
if( ! IGNode->isOnStack() ) {
double SpillCost = (double) IGNode->getParentLR()->getSpillCost() /
(double) (IGNode->getCurDegree() + 1);
if( isFirstNode ) { // for the first IG node
MinSpillCost = SpillCost;
MinCostIGNode = IGNode;
isFirstNode = false;
}
else if( MinSpillCost > SpillCost) {
MinSpillCost = SpillCost;
MinCostIGNode = IGNode;
}
}
}
assert( MinCostIGNode && "No IGNode to spill");
return MinCostIGNode;
}
//----------------------------------------------------------------------------
// Color the IGNode using the machine specific code.
//----------------------------------------------------------------------------
void RegClass::colorIGNode(IGNode *const Node)
{
if( ! Node->hasColor() ) { // not colored as an arg etc.
// init all elements of to IsColorUsedAr false;
//
for( unsigned i=0; i < MRC->getNumOfAllRegs(); i++) {
IsColorUsedArr[ i ] = false;
}
// init all reserved_regs to true - we can't use them
//
for( unsigned i=0; i < ReservedColorList->size() ; i++) {
IsColorUsedArr[ (*ReservedColorList)[i] ] = true;
}
// call the target specific code for coloring
//
MRC->colorIGNode(Node, IsColorUsedArr);
}
else {
if( DEBUG_RA ) {
cout << " Node " << Node->getIndex();
cout << " already colored with color " << Node->getColor() << endl;
}
}
if( !Node->hasColor() ) {
if( DEBUG_RA ) {
cout << " Node " << Node->getIndex();
cout << " - could not find a color (needs spilling)" << endl;
}
}
}
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