void
StupidAllocator::syncRegister(LInstruction *ins, RegisterIndex index)
{
if (registers[index].dirty) {
LMoveGroup *input = getInputMoveGroup(ins->id());
LAllocation *source = new LAllocation(registers[index].reg);
uint32_t existing = registers[index].vreg;
LAllocation *dest = stackLocation(existing);
input->addAfter(source, dest);
registers[index].dirty = false;
}
}
void
StupidAllocator::syncForBlockEnd(LBlock *block, LInstruction *ins)
{
// Sync any dirty registers, and update the synced state for phi nodes at
// each successor of a block. We cannot conflate the storage for phis with
// that of their inputs, as we cannot prove the live ranges of the phi and
// its input do not overlap. The values for the two may additionally be
// different, as the phi could be for the value of the input in a previous
// loop iteration.
for (size_t i = 0; i < registerCount; i++)
syncRegister(ins, i);
LMoveGroup *group = nullptr;
MBasicBlock *successor = block->mir()->successorWithPhis();
if (successor) {
uint32_t position = block->mir()->positionInPhiSuccessor();
LBlock *lirsuccessor = graph.getBlock(successor->id());
for (size_t i = 0; i < lirsuccessor->numPhis(); i++) {
LPhi *phi = lirsuccessor->getPhi(i);
uint32_t sourcevreg = phi->getOperand(position)->toUse()->virtualRegister();
uint32_t destvreg = phi->getDef(0)->virtualRegister();
if (sourcevreg == destvreg)
continue;
LAllocation *source = stackLocation(sourcevreg);
LAllocation *dest = stackLocation(destvreg);
if (!group) {
// The moves we insert here need to happen simultaneously with
// each other, yet after any existing moves before the instruction.
LMoveGroup *input = getInputMoveGroup(ins->id());
if (input->numMoves() == 0) {
group = input;
} else {
group = new LMoveGroup(alloc());
block->insertAfter(input, group);
}
}
group->add(source, dest);
}
}
}
void
RegisterAllocator::dumpInstructions()
{
#ifdef DEBUG
fprintf(stderr, "Instructions:\n");
for (size_t blockIndex = 0; blockIndex < graph.numBlocks(); blockIndex++) {
LBlock* block = graph.getBlock(blockIndex);
MBasicBlock* mir = block->mir();
fprintf(stderr, "\nBlock %lu", static_cast<unsigned long>(blockIndex));
for (size_t i = 0; i < mir->numSuccessors(); i++)
fprintf(stderr, " [successor %u]", mir->getSuccessor(i)->id());
fprintf(stderr, "\n");
for (size_t i = 0; i < block->numPhis(); i++) {
LPhi* phi = block->getPhi(i);
fprintf(stderr, "[%u,%u Phi] [def %s]",
inputOf(phi).bits(),
outputOf(phi).bits(),
phi->getDef(0)->toString());
for (size_t j = 0; j < phi->numOperands(); j++)
fprintf(stderr, " [use %s]", phi->getOperand(j)->toString());
fprintf(stderr, "\n");
}
for (LInstructionIterator iter = block->begin(); iter != block->end(); iter++) {
LInstruction* ins = *iter;
fprintf(stderr, "[");
if (ins->id() != 0)
fprintf(stderr, "%u,%u ", inputOf(ins).bits(), outputOf(ins).bits());
fprintf(stderr, "%s]", ins->opName());
if (ins->isMoveGroup()) {
LMoveGroup* group = ins->toMoveGroup();
for (int i = group->numMoves() - 1; i >= 0; i--) {
// Use two printfs, as LAllocation::toString is not reentant.
fprintf(stderr, " [%s", group->getMove(i).from()->toString());
fprintf(stderr, " -> %s]", group->getMove(i).to()->toString());
}
fprintf(stderr, "\n");
continue;
}
for (size_t i = 0; i < ins->numDefs(); i++)
fprintf(stderr, " [def %s]", ins->getDef(i)->toString());
for (size_t i = 0; i < ins->numTemps(); i++) {
LDefinition* temp = ins->getTemp(i);
if (!temp->isBogusTemp())
fprintf(stderr, " [temp %s]", temp->toString());
}
for (LInstruction::InputIterator alloc(*ins); alloc.more(); alloc.next()) {
if (!alloc->isBogus())
fprintf(stderr, " [use %s]", alloc->toString());
}
fprintf(stderr, "\n");
}
}
fprintf(stderr, "\n");
#endif // DEBUG
}
void
AllocationIntegrityState::dump()
{
#ifdef DEBUG
fprintf(stderr, "Register Allocation Integrity State:\n");
for (size_t blockIndex = 0; blockIndex < graph.numBlocks(); blockIndex++) {
LBlock* block = graph.getBlock(blockIndex);
MBasicBlock* mir = block->mir();
fprintf(stderr, "\nBlock %lu", static_cast<unsigned long>(blockIndex));
for (size_t i = 0; i < mir->numSuccessors(); i++)
fprintf(stderr, " [successor %u]", mir->getSuccessor(i)->id());
fprintf(stderr, "\n");
for (size_t i = 0; i < block->numPhis(); i++) {
const InstructionInfo& info = blocks[blockIndex].phis[i];
LPhi* phi = block->getPhi(i);
CodePosition input(block->getPhi(0)->id(), CodePosition::INPUT);
CodePosition output(block->getPhi(block->numPhis() - 1)->id(), CodePosition::OUTPUT);
fprintf(stderr, "[%u,%u Phi] [def %s] ",
input.bits(),
output.bits(),
phi->getDef(0)->toString());
for (size_t j = 0; j < phi->numOperands(); j++)
fprintf(stderr, " [use %s]", info.inputs[j].toString());
fprintf(stderr, "\n");
}
for (LInstructionIterator iter = block->begin(); iter != block->end(); iter++) {
LInstruction* ins = *iter;
const InstructionInfo& info = instructions[ins->id()];
CodePosition input(ins->id(), CodePosition::INPUT);
CodePosition output(ins->id(), CodePosition::OUTPUT);
fprintf(stderr, "[");
if (input != CodePosition::MIN)
fprintf(stderr, "%u,%u ", input.bits(), output.bits());
fprintf(stderr, "%s]", ins->opName());
if (ins->isMoveGroup()) {
LMoveGroup* group = ins->toMoveGroup();
for (int i = group->numMoves() - 1; i >= 0; i--) {
// Use two printfs, as LAllocation::toString is not reentrant.
fprintf(stderr, " [%s", group->getMove(i).from()->toString());
fprintf(stderr, " -> %s]", group->getMove(i).to()->toString());
}
fprintf(stderr, "\n");
continue;
}
for (size_t i = 0; i < ins->numDefs(); i++)
fprintf(stderr, " [def %s]", ins->getDef(i)->toString());
for (size_t i = 0; i < ins->numTemps(); i++) {
LDefinition* temp = ins->getTemp(i);
if (!temp->isBogusTemp())
fprintf(stderr, " [temp v%u %s]", info.temps[i].virtualRegister(),
temp->toString());
}
size_t index = 0;
for (LInstruction::InputIterator alloc(*ins); alloc.more(); alloc.next()) {
fprintf(stderr, " [use %s", info.inputs[index++].toString());
if (!alloc->isConstant())
fprintf(stderr, " %s", alloc->toString());
fprintf(stderr, "]");
}
fprintf(stderr, "\n");
}
}
// Print discovered allocations at the ends of blocks, in the order they
// were discovered.
Vector<IntegrityItem, 20, SystemAllocPolicy> seenOrdered;
seenOrdered.appendN(IntegrityItem(), seen.count());
for (IntegrityItemSet::Enum iter(seen); !iter.empty(); iter.popFront()) {
IntegrityItem item = iter.front();
seenOrdered[item.index] = item;
}
if (!seenOrdered.empty()) {
fprintf(stderr, "Intermediate Allocations:\n");
for (size_t i = 0; i < seenOrdered.length(); i++) {
IntegrityItem item = seenOrdered[i];
fprintf(stderr, " block %u reg v%u alloc %s\n",
item.block->mir()->id(), item.vreg, item.alloc.toString());
}
}
fprintf(stderr, "\n");
#endif
}
bool
AllocationIntegrityState::checkIntegrity(LBlock* block, LInstruction* ins,
uint32_t vreg, LAllocation alloc, bool populateSafepoints)
{
for (LInstructionReverseIterator iter(block->rbegin(ins)); iter != block->rend(); iter++) {
ins = *iter;
// Follow values through assignments in move groups. All assignments in
// a move group are considered to happen simultaneously, so stop after
// the first matching move is found.
if (ins->isMoveGroup()) {
LMoveGroup* group = ins->toMoveGroup();
for (int i = group->numMoves() - 1; i >= 0; i--) {
if (*group->getMove(i).to() == alloc) {
alloc = *group->getMove(i).from();
break;
}
}
}
const InstructionInfo& info = instructions[ins->id()];
// Make sure the physical location being tracked is not clobbered by
// another instruction, and that if the originating vreg definition is
// found that it is writing to the tracked location.
for (size_t i = 0; i < ins->numDefs(); i++) {
LDefinition* def = ins->getDef(i);
if (def->isBogusTemp())
continue;
if (info.outputs[i].virtualRegister() == vreg) {
MOZ_ASSERT(*def->output() == alloc);
// Found the original definition, done scanning.
return true;
} else {
MOZ_ASSERT(*def->output() != alloc);
}
}
for (size_t i = 0; i < ins->numTemps(); i++) {
LDefinition* temp = ins->getTemp(i);
if (!temp->isBogusTemp())
MOZ_ASSERT(*temp->output() != alloc);
}
if (ins->safepoint()) {
if (!checkSafepointAllocation(ins, vreg, alloc, populateSafepoints))
return false;
}
}
// Phis are effectless, but change the vreg we are tracking. Check if there
// is one which produced this vreg. We need to follow back through the phi
// inputs as it is not guaranteed the register allocator filled in physical
// allocations for the inputs and outputs of the phis.
for (size_t i = 0; i < block->numPhis(); i++) {
const InstructionInfo& info = blocks[block->mir()->id()].phis[i];
LPhi* phi = block->getPhi(i);
if (info.outputs[0].virtualRegister() == vreg) {
for (size_t j = 0, jend = phi->numOperands(); j < jend; j++) {
uint32_t newvreg = info.inputs[j].toUse()->virtualRegister();
LBlock* predecessor = block->mir()->getPredecessor(j)->lir();
if (!addPredecessor(predecessor, newvreg, alloc))
return false;
}
return true;
}
}
// No phi which defined the vreg we are tracking, follow back through all
// predecessors with the existing vreg.
for (size_t i = 0, iend = block->mir()->numPredecessors(); i < iend; i++) {
LBlock* predecessor = block->mir()->getPredecessor(i)->lir();
if (!addPredecessor(predecessor, vreg, alloc))
return false;
}
return true;
}
bool
GreedyAllocator::allocateRegisters()
{
// Allocate registers bottom-up, such that we see all uses before their
// definitions.
for (size_t i = graph.numBlocks() - 1; i < graph.numBlocks(); i--) {
LBlock *block = graph.getBlock(i);
IonSpew(IonSpew_RegAlloc, "Allocating block %d", (uint32)i);
// All registers should be free.
JS_ASSERT(state.free == RegisterSet::All());
// Allocate stack for any phis.
for (size_t j = 0; j < block->numPhis(); j++) {
LPhi *phi = block->getPhi(j);
VirtualRegister *vreg = getVirtualRegister(phi->getDef(0));
allocateStack(vreg);
}
// Allocate registers.
if (!allocateRegistersInBlock(block))
return false;
LMoveGroup *entrySpills = block->getEntryMoveGroup();
// We've reached the top of the block. Spill all registers by inserting
// moves from their stack locations.
for (AnyRegisterIterator iter(RegisterSet::All()); iter.more(); iter++) {
VirtualRegister *vreg = state[*iter];
if (!vreg) {
JS_ASSERT(state.free.has(*iter));
continue;
}
JS_ASSERT(vreg->reg() == *iter);
JS_ASSERT(!state.free.has(vreg->reg()));
allocateStack(vreg);
LAllocation *from = LAllocation::New(vreg->backingStack());
LAllocation *to = LAllocation::New(vreg->reg());
if (!entrySpills->add(from, to))
return false;
killReg(vreg);
vreg->unsetRegister();
}
// Before killing phis, ensure that each phi input has its own stack
// allocation. This ensures we won't allocate the same slot for any phi
// as its input, which technically may be legal (since the phi becomes
// the last use of the slot), but we avoid for sanity.
for (size_t i = 0; i < block->numPhis(); i++) {
LPhi *phi = block->getPhi(i);
for (size_t j = 0; j < phi->numOperands(); j++) {
VirtualRegister *in = getVirtualRegister(phi->getOperand(j)->toUse());
allocateStack(in);
}
}
// Kill phis.
for (size_t i = 0; i < block->numPhis(); i++) {
LPhi *phi = block->getPhi(i);
VirtualRegister *vr = getVirtualRegister(phi->getDef(0));
JS_ASSERT(!vr->hasRegister());
killStack(vr);
}
}
return true;
}