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();
}
}
bool FpuStackAllocator::merge_fpu_stack_with_successors(BlockBegin* block) {
#ifndef PRODUCT
if (TraceFPUStack) {
tty->print_cr("Propagating FPU stack state for B%d at LIR_Op position %d to successors:",
block->block_id(), pos());
sim()->print();
tty->cr();
}
#endif
bool changed = false;
int number_of_sux = block->number_of_sux();
if (number_of_sux == 1 && block->sux_at(0)->number_of_preds() > 1) {
// The successor has at least two incoming edges, so a stack merge will be necessary
// If this block is the first predecessor, cleanup the current stack and propagate it
// If this block is not the first predecessor, a stack merge will be necessary
BlockBegin* sux = block->sux_at(0);
intArray* state = sux->fpu_stack_state();
LIR_List* instrs = new LIR_List(_compilation);
if (state != NULL) {
// Merge with a successors that already has a FPU stack state
// the block must only have one successor because critical edges must been split
FpuStackSim* cur_sim = sim();
FpuStackSim* sux_sim = temp_sim();
sux_sim->read_state(state);
merge_fpu_stack(instrs, cur_sim, sux_sim);
} else {
// propagate current FPU stack state to successor without state
// clean up stack first so that there are no dead values on the stack
if (ComputeExactFPURegisterUsage) {
FpuStackSim* cur_sim = sim();
ResourceBitMap live_fpu_regs = block->sux_at(0)->fpu_register_usage();
assert(live_fpu_regs.size() == FrameMap::nof_fpu_regs, "missing register usage");
merge_cleanup_fpu_stack(instrs, cur_sim, live_fpu_regs);
}
intArray* state = sim()->write_state();
if (TraceFPUStack) {
tty->print_cr("Setting FPU stack state of B%d (merge path)", sux->block_id());
sim()->print(); tty->cr();
}
sux->set_fpu_stack_state(state);
}
if (instrs->instructions_list()->length() > 0) {
lir()->insert_before(pos(), instrs);
set_pos(instrs->instructions_list()->length() + pos());
changed = true;
}
} else {
// Propagate unmodified Stack to successors where a stack merge is not necessary
intArray* state = sim()->write_state();
for (int i = 0; i < number_of_sux; i++) {
BlockBegin* sux = block->sux_at(i);
#ifdef ASSERT
for (int j = 0; j < sux->number_of_preds(); j++) {
assert(block == sux->pred_at(j), "all critical edges must be broken");
}
// check if new state is same
if (sux->fpu_stack_state() != NULL) {
intArray* sux_state = sux->fpu_stack_state();
assert(state->length() == sux_state->length(), "overwriting existing stack state");
for (int j = 0; j < state->length(); j++) {
assert(state->at(j) == sux_state->at(j), "overwriting existing stack state");
}
}
#endif
#ifndef PRODUCT
if (TraceFPUStack) {
tty->print_cr("Setting FPU stack state of B%d", sux->block_id());
sim()->print(); tty->cr();
}
#endif
sux->set_fpu_stack_state(state);
}
}
#ifndef PRODUCT
// assertions that FPU stack state conforms to all successors' states
intArray* cur_state = sim()->write_state();
for (int i = 0; i < number_of_sux; i++) {
BlockBegin* sux = block->sux_at(i);
intArray* sux_state = sux->fpu_stack_state();
assert(sux_state != NULL, "no fpu state");
assert(cur_state->length() == sux_state->length(), "incorrect length");
for (int i = 0; i < cur_state->length(); i++) {
assert(cur_state->at(i) == sux_state->at(i), "element not equal");
}
}
#endif
return changed;
}