void Forest::Color()
{
int nn, m;
int c;
int j, k = 17;
int *p;
CSet used;
Tree *t;
if (pass == 1) {
for (c = 0; c < treecount; c++) {
trees[c]->spill = false;
trees[c]->color = k;
if (trees[c]->var < 3)
trees[c]->color = trees[c]->var;
if (trees[c]->var >= regFirstArg && trees[c]->var <= regLastArg) {
trees[c]->color = trees[c]->var - regFirstArg + 18;
}
if (trees[c]->var == regFP
|| trees[c]->var == regLR
|| trees[c]->var == regXLR
|| trees[c]->var == regSP) {
trees[c]->color = trees[c]->var - regXLR + 28;
}
}
}
used.clear();
used.add(0); // reg0 is a constant 0
used.add(1); // these two are return value
used.add(2);
while (!stk->IsEmpty()) {
t = trees[m=pop()];
if (pass == 1 && !t->infinite && t->cost < 0.0f) { // was <= 0.0f
t->spill = true;
}
else {
p = iGraph.GetNeighbours(m, &nn);
for (j = 0; j < nn; j++)
used.add(trees[p[j]]->color);
for (c = 0; used.isMember(c) && c < k; c++);
if (c < k && t->color == k) { // The tree may have been colored already
t->color = c;
used.add(c);
}
else if (t->color <= k) // Don't need to spill args
t->spill = true;
}
}
}
bool Forest::SpillCode()
{
int c, m, n;
Var *v;
Tree *t;
BasicBlock *bb;
int64_t spillOffset;
OCODE *cd;
CSet spilled;
bool ret;
ret = false;
cd = currentFn->spAdjust;
if (cd == nullptr)
return (ret);
spillOffset = cd->oper3->offset->i;
spilled.clear();
for (c = 0; c < treecount; c++) {
t = trees[c]; // convenience
// Tree couldn't be colored that means there are no available registers.
// So, spill one of the registers. The register to spill should be one
// that isn't live at the same time as this tree.
if (t->spill) {
ret = true;
v = Var::Find(t->var);
v = v->GetVarToSpill(&spilled);
if (v == nullptr)
continue;
// The var is spilled at the head of the tree, and restored later
t->blocks->resetPtr();
m = t->blocks->nextMember();
if (m >= 0) { // should always be true, otherwise no code
bb = basicBlocks[m];
if (!spilled.isMember(v->num)) {
v->spillOffset = spillOffset;
spillOffset += sizeOfWord;
spilled.add(v->num);
}
bb->InsertSpillCode(v->num, -v->spillOffset);
while(1) {
n = m;
m = t->blocks->nextMember();
if (m < 0)
break;
// Detect when a different branch is present. The node
// number will jump by more than 1 between branches.
// *** suspect this won't work, should just pick last block in tree
if (m - n > 1) {
bb = basicBlocks[n];
bb->InsertFillCode(v->num, -v->spillOffset);
}
}
bb = basicBlocks[n];
bb->InsertFillCode(v->num, -v->spillOffset);
}
t->spill = false;
}
}
cd->oper3->offset->i = spillOffset;
return (ret);
}