void PerformanceDebugger::report_context(InlinedScope* s) {
if (!DebugPerformance) return;
Reporter r(this);
GrowableArray<Expr*>* temps = s->contextTemporaries();
const int len = temps->length();
int nused = 0;
for (int i = 0; i < len; i++) {
PReg* r = temps->at(i)->preg();
if (r->uplevelR() || r->uplevelW() || (r->isBlockPReg() && !r->isUnused())) nused++;
}
if (nused == 0) {
str->print(" could not eliminate context of scope %s (fixable compiler restriction; should be eliminated)\n", s->key()->print_string());
} else {
str->print(" could not eliminate context of scope %s; temp(s) still used: ", s->key()->print_string());
for (int j = 0; j < len; j++) {
PReg* r = temps->at(j)->preg();
if (r->uplevelR() || r->uplevelW()) {
str->print("%d ", j);
} else if (r->isBlockPReg() && !r->isUnused()) {
str->print("%d (non-inlined block)", j);
}
}
str->print("\n");
}
}
void BB::allocateTempRegisters(BitVector** hardwired, PRegBList* tempRegs,
BitVectorBList* lives) {
if (!nnodes) return; // empty BB
RegisterEqClassBList regClasses(nnodes + 1);
regClasses.append(NULL); // first reg class has index 1
fint use_count[NumRegisters], def_count[NumRegisters];
for (fint i = 0; i < NumRegisters; i++) use_count[i] = def_count[i] = 0;
allocate_to_preferred_candidates_if_possible(use_count, def_count);
// allocate other temp regs (using the untouched temp regs of this BB)
fint temp = 0;
for (int i = 0; i < duInfo.info->length(); i++) {
// collect temp regs
PReg* r = duInfo.info->nth(i)->reg;
if (r->loc == UnAllocated && !r->isUnused() && r->isLocalTo(this)) {
assert(r->dus.first()->index == i, "should be the same");
for ( ; temp < NumTempRegs &&
use_count[TempRegs[temp]] + def_count[TempRegs[temp]] > 0;
temp++) ;
if (temp == NumTempRegs) break; // ran out of regs
// ok, allocate TempRegs[temp] to the preg and equivalent pregs
Location t = TempRegs[temp++];
PReg* frst = r->regClass ? regClasses.nth(r->regClass)->first : r;
for (PReg* pr = frst; pr; pr = pr->regClassLink) {
doAlloc(pr, t);
pr->regClass = 0;
}
}
r->regClass = 0;
}
if (temp == NumTempRegs) {
// ran out of temp regs with the simple strategy - try using slow
// allocation algorithm
slowAllocateTempRegisters(hardwired, tempRegs, lives);
}
}
void Compiler::computeBlockInfo() {
FlagSetting(EliminateUnneededNodes, true); // unused context nodes must be eliminated
GrowableArray<InlinedScope*>* allContexts = new GrowableArray<InlinedScope*>(25);
topScope->collectContextInfo(allContexts);
// for now, just allocate all contexts as in interpreter
// fix this later: collect all uplevel-accessed PRegs at same loop depth, form physical
// contexts for these
// also, if uplevel-read and single def --> could copy into context and keep
// stack/register copy
// remove all unused contexts
// need to iterate because removing a nested context may enable removal of a parent context
// (could avoid iteration with topo sort, but there are few contexts anyway)
bool changed = EliminateContexts;
while (changed) {
changed = false;
for (int i = allContexts->length() - 1; i >= 0; i--) {
InlinedScope* s = allContexts->at(i);
if (s == NULL) continue;
PReg* contextPR = s->context();
assert(contextPR->isSinglyAssigned(), "should have exactly one def");
GrowableArray<Expr*>* temps = s->contextTemporaries();
bool noUplevelAccesses = true;
// check if all context temps can be stack-allocated
for (int j = temps->length() - 1; j >= 0; j--) {
PReg* r = temps->at(j)->preg();
if (r->uplevelR() || r->uplevelW() // this temp is still uplevel-accessed, so can't eliminate context
|| (r->isBlockPReg() && !r->isUnused()) // this block still forces a context
) {
noUplevelAccesses = false;
break;
}
}
// TO DO: check if context is needed for NLRs
// (noUplevelAccesses alone does not allow elimination)
if (/*noUplevelAccesses || */contextPR->isSinglyUsed()) {
// can eliminate context -- no uplevel-accessed vars
// (single use is context initializer)
if (CompilerDebug) cout(PrintEliminateContexts)->print("%*s*eliminating context %s\n", s->depth, "", contextPR->safeName());
contextPR->scope()->gen()->removeContextCreation();
allContexts->at_put(i, NULL); // make code generator break if it tries to access this context
changed = true;
}
}
}
// now collect all remaining contexts
int i = allContexts->length();
contextList = new GrowableArray<InlinedScope*>(i, i, NULL);
while (i-- > 0) {
// should merge several contexts into one physical context if possible
// fix this later
InlinedScope* s = allContexts->at(i);
if (s == NULL) continue;
PReg* contextPR = s->context();
if (CompilerDebug) {
cout(PrintEliminateContexts)->print("%*s*could not eliminate context %s in scope %s\n",
s->depth, "", contextPR->safeName(), s->key()->print_string());
}
reporter->report_context(s);
contextList->at_put(i, s);
ContextCreateNode* c = s->contextInitializer()->creator();
c->set_contextNo(i);
GrowableArray<Expr*>* temps = s->contextTemporaries();
// allocate the temps in this context (but only if they're used)
int ntemps = temps->length();
int size = 0;
for (int j = 0; j < ntemps; j++) {
PReg* p = temps->at(j)->preg();
// should be:
// if (p->isUsed() && (p->uplevelR() || p->uplevelW())) {
// but doesn't work yet (probably must fix set_self_via_context etc.)
// -Urs 6/96
if (p->isUsed()) {
// allocate p to context temp
assert(p->scope() == s || p->isBlockPReg(), "oops");
Location loc = Mapping::contextTemporary(i, size, s->scopeID());
if (p->isBlockPReg()) {
// Blocks aren't actually assigned (at the PReg level) so that the inlining info
// isn't lost. Thus we need to create a fake destination here if the context exists.
SAPReg* dest = new SAPReg(s, loc, true, true, PrologueBCI, EpilogueBCI);
Expr* e = new UnknownExpr(dest, NULL);
//contextPR->scope()->contextInitializer()->initialize(j, init);
temps->at_put(j, e);
} else {
p->allocateTo(loc);
}
size++;
}
}
c->set_sizeOfContext(size);
if (size < ntemps && c->scope()->number_of_noninlined_blocks() > 0) {
// this hasn't been exercised much
compiler_warning("while compiling %s: eliminated some context temps", key->print_string());
}
}
// Compute the number of noninlined blocks for the nmethod and allocate
const int nblocks = topScope->number_of_noninlined_blocks();
if (is_method_compile() || nblocks > 0) {
// allocate nblocks+1 jumpTable entries
const jumpTableID id = Universe::code->jump_table()->allocate(nblocks + 1);
if (is_method_compile()) {
main_jumpTable_id = id;
} else {
promoted_jumpTable_id = id;
}
// first is for nmethod itself
int block_index = 1;
for (int i = bbIterator->exposedBlks->length() - 1; i >= 0; i--) {
BlockPReg* blk = bbIterator->exposedBlks->at(i);
if (blk->isUsed()) {
assert(block_index <= nblocks, "nblocks too small");
blk->closure()->set_id(id.sub(block_index++));
}
}
assert(nblocks + 1 == block_index, "just checking");
}
}
// allocate PRegs that are used & defined solely within this BB
void BB::slowAllocateTempRegisters(BitVector** hardwired, PRegBList* tempRegs,
BitVectorBList* lives) {
// clear temporary data structures
tempRegs->clear();
lives->clear();
fint i;
for (i = 0; i < NumTempRegs; i++) {
hardwired[i]->setLength(nnodes);
hardwired[i]->clear();
}
for (i = 0; i < duInfo.info->length(); i++) {
// collect temp regs and hardwired temp regs
PReg* r = duInfo.info->nth(i)->reg;
if (r->isLocalTo(this)) {
assert(r->dus.first()->index == i, "should be the same");
if (r->isUnused()) {
// unused register - ignore
} else {
DUInfo* info = duInfo.info->nth(r->dus.first()->index);
tempRegs->append(r);
BitVector* bv = new BitVector(nnodes);
lives->append(bv);
fint firstUse = 0, lastUse = nnodes - 1;
duInfo.info->nth(i)->getLiveRange(firstUse, lastUse);
bv->addFromTo(firstUse, lastUse);
}
} else if (isTempReg(r->loc)) {
fint firstUse = 0, lastUse = nnodes - 1;
if (!r->incorrectDU()) {
duInfo.info->nth(i)->getLiveRange(firstUse, lastUse);
} else {
// can't really compute live range since the temp might be non-local
// so assume it's live from first node til the end
}
hardwired[RegToTempNo[r->loc]]->addFromTo(firstUse, lastUse);
}
}
// now, tempRegs holds all temp regs, and lives contains each register's
// live range (one bit per node, 1 = reg is live); hardwired contains
// the ranges where temp regs are already taken (e.g. for NLR, calls, etc)
// cycle through the temp registers to (hopefully) allow more optimizations
// later (e.g. scheduling)
fint lastTemp = 0;
# define nextTemp(n) (n == NumTempRegs - 1) ? 0 : n + 1
for (i = 0; i < tempRegs->length(); i++) {
// try to allocate tempRegs[i] to a temp register
PReg* r = tempRegs->nth(i);
if (r->loc != UnAllocated) {
assert(r->regClass == 0, "should have been cleared");
continue;
}
BitVector* liveRange = lives->nth(i);
for (fint tempNo = lastTemp, ntries = 0; ntries < NumTempRegs;
tempNo = nextTemp(tempNo), ntries++) {
if (liveRange->isDisjointFrom(hardwired[tempNo])) {
Location temp = TempRegs[tempNo];
doAlloc(r, temp);
hardwired[tempNo]->unionWith(liveRange);
lastTemp = nextTemp(tempNo);
break;
}
}
if ( r->loc == UnAllocated
&& (PrintSICTempRegisterAllocation
|| WizardMode && TARGET_ARCH != I386_ARCH /* happens normally in I386; few regs */ )) {
lprintf("*could NOT find temp assignment for local %s in BB%ld\n",
r->name(), (void*)id());
} else if (r->loc == UnAllocated) {
if (PrintSICTempRegisterAllocation) lprintf("out of temp regs");
}
r->regClass = 0;
}
}
