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 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");
}
}