BlockBegin* LoopFinder::insert_caching_block(LoopList* loops, BlockBegin* from, BlockBegin* to) {
if (from->next() && from->next()->as_CachingChange() != NULL &&
from->end()->default_sux() == to) {
// we already have a caching change block
// check that the precision flags are the same
#ifdef ASSERT
CachingChange* cc = from->next()->as_CachingChange();
assert(cc->pred_block()->is_set(BlockBegin::single_precision_flag) == from->is_set(BlockBegin::single_precision_flag), "consistency check");
assert(cc->sux_block()->is_set(BlockBegin::single_precision_flag) == to->is_set(BlockBegin::single_precision_flag), "consistency check");
#endif
return NULL;
} else {
// insert a caching change block, making it close to any single successor
int bci = -1;
BlockLoopInfo* bli = get_block_info(to);
if (bli->nof_preds() == 1) {
bci = to->bci();
} else {
bci = from->end()->bci();
}
BlockBegin* cc = new_block(to->scope(), bci);
BlockEnd* e = new Goto(to, false);
cc->set_end(e);
cc->set_next(new CachingChange(from, to), bci)->set_next(e, bci);
if (PrintLoops && Verbose) {
tty->print_cr("Added caching block B%d (dest B%d)", cc->block_id(), to->block_id());
}
BlockEnd* from_end = from->end();
from_end->substitute_sux(to, cc);
cc->join(from_end->state());
assert(cc->state() != NULL, "illegal operation");
ValueStack* end_state = cc->state()->copy();
cc->end()->set_state(end_state);
to->join(end_state);
assert(cc->end()->state() != NULL, "should have state");
loops->update_loops(from, to, cc);
return cc;
}
}
// Gather backedges of natural loops: an edge a -> b where b dominates a
LoopList* LoopFinder::find_backedges(boolArray* visited) {
int i;
LoopList* backedges = new LoopList();
for (i = 0; i < max_blocks(); i++) {
if (visited->at(i)) {
BlockLoopInfo* bli = _info->at(i);
BlockBegin* bb = bli->block();
BlockEnd* be = bb->end();
int n = be->number_of_sux();
for (int i = 0; i < n; i++) {
BlockBegin* sux = be->sux_at(i);
if (bli->is_dom_block(sux->block_id())) {
bli->mark_backedge_start();
backedges->push(new Loop(sux, bb));
}
}
}
}
// backedges contains single pairs of blocks which are a backedge.
// some of these loops may share entry points, so walk over the backedges
// and merge loops which have the same entry point
if (backedges->length() > 1) {
backedges->sort(sort_by_start_block);
Loop* current_loop = backedges->at(0);
for (i = 1; i < backedges->length();) {
Loop* this_loop = backedges->at(i);
if (current_loop->start() == this_loop->start()) {
// same entry point
assert(this_loop->ends()->length() == 1, "should only have one end at this point");
#ifndef PRODUCT
if (PrintLoops && Verbose) {
tty->print_cr("Merging loops with same start");
current_loop->print();
this_loop->print();
}
#endif
BlockBegin* e = this_loop->ends()->at(0);
current_loop->add_end(e);
backedges->remove(this_loop);
} else {
// start processing the next loop entry point
i++;
}
}
}
return backedges;
}
BlockListScanInfo(BlockList* blocks) : _info(new RegisterManager()), _had_call(false) {
for (int n = 0; n < blocks->length(); n++) {
BlockBegin* b = blocks->at(n);
if (b->lir() != NULL) {
traverse(b, b->lir()->instructions_list());
}
// Registers may be used to hold the value
// on the top of stack so check for that.
check_stack(b->state());
check_stack(b->end()->state());
}
if (_had_call) {
for (int i = 0; i < FrameMap::nof_caller_save_cpu_regs; i++) {
_info->lock(FrameMap::caller_save_cpu_reg_at(i)->as_rinfo());
}
}
}
void FpuStackAllocator::allocate() {
int num_blocks = allocator()->block_count();
for (int i = 0; i < num_blocks; i++) {
// Set up to process block
BlockBegin* block = allocator()->block_at(i);
intArray* fpu_stack_state = block->fpu_stack_state();
#ifndef PRODUCT
if (TraceFPUStack) {
tty->cr();
tty->print_cr("------- Begin of new Block %d -------", block->block_id());
}
#endif
assert(fpu_stack_state != NULL ||
block->end()->as_Base() != NULL ||
block->is_set(BlockBegin::exception_entry_flag),
"FPU stack state must be present due to linear-scan order for FPU stack allocation");
// note: exception handler entries always start with an empty fpu stack
// because stack merging would be too complicated
if (fpu_stack_state != NULL) {
sim()->read_state(fpu_stack_state);
} else {
sim()->clear();
}
#ifndef PRODUCT
if (TraceFPUStack) {
tty->print("Reading FPU state for block %d:", block->block_id());
sim()->print();
tty->cr();
}
#endif
allocate_block(block);
CHECK_BAILOUT();
}
}
