1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-30 07:22:55 +01:00
llvm-mirror/lib/CodeGen/RegAlloc/RegClass.cpp
Vikram S. Adve 57eb4ab6bc (1) Change the way unused regs. are marked and found to consider regType
info (since multiple reg types may share the same reg class).
(2) Remove machine-specific regalloc. methods that are no longer needed.
    In particular, arguments and return value from a call do not need
    machine-specific code for allocation.
(3) Rename TargetRegInfo::getRegType variants to avoid unintentional
    overloading when an include file is omitted.

llvm-svn: 7329
2003-07-25 21:06:09 +00:00

268 lines
8.3 KiB
C++

//===-- RegClass.cpp -----------------------------------------------------===//
//
// class RegClass for coloring-based register allocation for LLVM.
//
//===----------------------------------------------------------------------===//
#include "RegClass.h"
#include "RegAllocCommon.h"
#include "llvm/CodeGen/IGNode.h"
#include "llvm/Target/TargetRegInfo.h"
using std::cerr;
//----------------------------------------------------------------------------
// This constructor inits IG. The actual matrix is created by a call to
// createInterferenceGraph() above.
//----------------------------------------------------------------------------
RegClass::RegClass(const Function *M,
const TargetRegInfo *_MRI_,
const TargetRegClassInfo *_MRC_)
: Meth(M), MRI(_MRI_), MRC(_MRC_),
RegClassID( _MRC_->getRegClassID() ),
IG(this), IGNodeStack() {
if( DEBUG_RA >= RA_DEBUG_Interference)
cerr << "Created Reg Class: " << RegClassID << "\n";
IsColorUsedArr.resize(MRC->getNumOfAllRegs());
}
//----------------------------------------------------------------------------
// Main entry point for coloring a register class.
//----------------------------------------------------------------------------
void RegClass::colorAllRegs()
{
if(DEBUG_RA >= RA_DEBUG_Coloring)
cerr << "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 >= RA_DEBUG_Coloring) {
cerr << " Puhsed all-unconstrained IGNodes. ";
if( PushedAll ) cerr << " No constrained nodes left.";
cerr << "\n";
}
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();
if (DEBUG_RA >= RA_DEBUG_Coloring)
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 >= RA_DEBUG_Coloring) {
cerr << " pushed un-constrained IGNode " << IGNode->getIndex() ;
cerr << " on to stack\n";
}
}
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 = 0;
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;
clearColorsUsed();
// initialize all colors used by neighbors of this node to true
LiveRange *LR = Node->getParentLR();
unsigned NumNeighbors = Node->getNumOfNeighbors();
for (unsigned n=0; n < NumNeighbors; n++) {
IGNode *NeighIGNode = Node->getAdjIGNode(n);
LiveRange *NeighLR = NeighIGNode->getParentLR();
// Don't use a color if it is in use by the neighbour,
// or is suggested for use by the neighbour,
// markColorsUsed() should be given the color and the reg type for
// LR, not for NeighLR, because it should mark registers used based on
// the type we are looking for, not on the regType for the neighbour.
if (NeighLR->hasColor())
this->markColorsUsed(NeighLR->getColor(),
MRI->getRegTypeForLR(NeighLR),
MRI->getRegTypeForLR(LR)); // use LR, not NeighLR
else if (NeighLR->hasSuggestedColor() &&
NeighLR->isSuggestedColorUsable())
this->markColorsUsed(NeighLR->getSuggestedColor(),
MRI->getRegTypeForLR(NeighLR),
MRI->getRegTypeForLR(LR)); // use LR, not NeighLR
}
// call the target specific code for coloring
//
MRC->colorIGNode(Node, IsColorUsedArr);
}
else {
if( DEBUG_RA >= RA_DEBUG_Coloring) {
cerr << " Node " << Node->getIndex();
cerr << " already colored with color " << Node->getColor() << "\n";
}
}
if( !Node->hasColor() ) {
if( DEBUG_RA >= RA_DEBUG_Coloring) {
cerr << " Node " << Node->getIndex();
cerr << " - could not find a color (needs spilling)\n";
}
}
}
void RegClass::printIGNodeList() const {
std::cerr << "IG Nodes for Register Class " << RegClassID << ":" << "\n";
IG.printIGNodeList();
}
void RegClass::printIG() {
std::cerr << "IG for Register Class " << RegClassID << ":" << "\n";
IG.printIG();
}