void FrameState::clear() {
clearCse();
clearLocals(*this);
m_frameSpansCall = false;
m_spValue = m_fpValue = nullptr;
m_spOffset = 0;
m_thisAvailable = false;
m_marker = BCMarker();
m_snapshots.clear();
assert(m_inlineSavedStates.empty());
}
/*
* Merge current state into state. Frame pointers and stack depth must match.
* If the stack pointer tmps are different, clear the tracked value (we can
* make a new one, given fp and spOffset).
*
* thisIsAvailable remains true if it's true in both states.
* local variable values are preserved if the match in both states.
* types are combined using Type::unionOf.
*/
void FrameState::merge(Snapshot& state) {
// cannot merge fp or spOffset state, so assert they match
assert(state.fpValue == m_fpValue);
assert(state.spOffset == m_spOffset);
assert(state.curFunc == m_curFunc);
if (state.spValue != m_spValue) {
// we have two different sp definitions but we know they're equal
// because spOffset matched.
state.spValue = nullptr;
}
// this is available iff it's available in both states
state.thisAvailable &= m_thisAvailable;
assert(m_locals.size() == state.locals.size());
for (unsigned i = 0; i < m_locals.size(); ++i) {
auto& local = state.locals[i];
// preserve local values if they're the same in both states,
// This would be the place to insert phi nodes (jmps+deflabels) if we want
// to avoid clearing state, which triggers a downstream reload.
if (local.value != m_locals[i].value) local.value = nullptr;
if (local.typeSource != m_locals[i].typeSource) local.typeSource = nullptr;
local.type = Type::unionOf(local.type, m_locals[i].type);
}
// TODO(t3729135): If we are merging states from different bytecode
// paths, we must conservatively clear the CSE table. Since the
// markers may or may not have been updated, we always clear. What
// we need is a global CSE algorithm.
if (RuntimeOption::EvalHHIRBytecodeControlFlow) {
clearCse();
}
// For now, we shouldn't be merging states with different inline states.
assert(m_inlineSavedStates == state.inlineSavedStates);
}
void FrameState::update(const IRInstruction* inst) {
FTRACE(3, "FrameState::update processing {}\n", *inst);
if (auto* taken = inst->taken()) {
// When we're building the IR, we append a conditional jump after
// generating its target block: see emitJmpCondHelper, where we
// call makeExit() before gen(JmpZero). It doesn't make sense to
// update the target block state at this point, so don't. The
// state doesn't have this problem during optimization passes,
// because we'll always process the jump before the target block.
if (!m_building || taken->empty()) save(taken);
}
auto const opc = inst->op();
getLocalEffects(inst, *this);
switch (opc) {
case DefInlineFP: trackDefInlineFP(inst); break;
case InlineReturn: trackInlineReturn(inst); break;
case Call:
m_spValue = inst->dst();
m_frameSpansCall = true;
// A call pops the ActRec and pushes a return value.
m_spOffset -= kNumActRecCells;
m_spOffset += 1;
assert(m_spOffset >= 0);
clearCse();
break;
case CallArray:
m_spValue = inst->dst();
m_frameSpansCall = true;
// A CallArray pops the ActRec an array arg and pushes a return value.
m_spOffset -= kNumActRecCells;
assert(m_spOffset >= 0);
clearCse();
break;
case ContEnter:
clearCse();
break;
case DefFP:
case FreeActRec:
m_fpValue = inst->dst();
break;
case ReDefResumableSP:
m_spValue = inst->dst();
break;
case ReDefSP:
m_spValue = inst->dst();
m_spOffset = inst->extra<ReDefSP>()->spOffset;
break;
case DefInlineSP:
case DefSP:
m_spValue = inst->dst();
m_spOffset = inst->extra<StackOffset>()->offset;
break;
case AssertStk:
case CastStk:
case CoerceStk:
case CheckStk:
case GuardStk:
case ExceptionBarrier:
m_spValue = inst->dst();
break;
case SpillStack: {
m_spValue = inst->dst();
// Push the spilled values but adjust for the popped values
int64_t stackAdjustment = inst->src(1)->intVal();
m_spOffset -= stackAdjustment;
m_spOffset += spillValueCells(inst);
break;
}
case SpillFrame:
case CufIterSpillFrame:
m_spValue = inst->dst();
m_spOffset += kNumActRecCells;
break;
case InterpOne:
case InterpOneCF: {
m_spValue = inst->dst();
auto const& extra = *inst->extra<InterpOneData>();
int64_t stackAdjustment = extra.cellsPopped - extra.cellsPushed;
// push the return value if any and adjust for the popped values
m_spOffset -= stackAdjustment;
break;
}
case AssertLoc:
case GuardLoc:
case CheckLoc:
m_fpValue = inst->dst();
break;
case LdThis:
m_thisAvailable = true;
break;
default:
break;
}
if (inst->modifiesStack()) {
m_spValue = inst->modifiedStkPtr();
}
// update the CSE table
if (m_enableCse && inst->canCSE()) {
cseInsert(inst);
}
// if the instruction kills any of its sources, remove them from the
// CSE table
if (inst->killsSources()) {
for (int i = 0; i < inst->numSrcs(); ++i) {
if (inst->killsSource(i)) {
cseKill(inst->src(i));
}
}
}
// Save state for each block at the end.
if (inst->isTerminal()) {
save(inst->block());
}
}
void FrameState::update(const IRInstruction* inst) {
if (auto* taken = inst->taken()) {
save(taken);
}
auto const opc = inst->op();
getLocalEffects(inst, *this);
switch (opc) {
case DefInlineFP: trackDefInlineFP(inst); break;
case InlineReturn: trackInlineReturn(inst); break;
case Call:
m_spValue = inst->dst();
m_frameSpansCall = true;
// A call pops the ActRec and pushes a return value.
m_spOffset -= kNumActRecCells;
m_spOffset += 1;
assert(m_spOffset >= 0);
clearCse();
break;
case CallArray:
m_spValue = inst->dst();
m_frameSpansCall = true;
// A CallArray pops the ActRec an array arg and pushes a return value.
m_spOffset -= kNumActRecCells;
assert(m_spOffset >= 0);
clearCse();
break;
case ContEnter:
clearCse();
break;
case DefFP:
case FreeActRec:
m_fpValue = inst->dst();
break;
case ReDefGeneratorSP:
m_spValue = inst->dst();
break;
case ReDefSP:
m_spValue = inst->dst();
m_spOffset = inst->extra<ReDefSP>()->spOffset;
break;
case DefInlineSP:
case DefSP:
m_spValue = inst->dst();
m_spOffset = inst->extra<StackOffset>()->offset;
break;
case AssertStk:
case AssertStkVal:
case CastStk:
case CoerceStk:
case CheckStk:
case GuardStk:
case ExceptionBarrier:
m_spValue = inst->dst();
break;
case SpillStack: {
m_spValue = inst->dst();
// Push the spilled values but adjust for the popped values
int64_t stackAdjustment = inst->src(1)->getValInt();
m_spOffset -= stackAdjustment;
m_spOffset += spillValueCells(inst);
break;
}
case SpillFrame:
case CufIterSpillFrame:
m_spValue = inst->dst();
m_spOffset += kNumActRecCells;
break;
case InterpOne:
case InterpOneCF: {
m_spValue = inst->dst();
auto const& extra = *inst->extra<InterpOneData>();
int64_t stackAdjustment = extra.cellsPopped - extra.cellsPushed;
// push the return value if any and adjust for the popped values
m_spOffset -= stackAdjustment;
break;
}
case AssertLoc:
case GuardLoc:
case CheckLoc:
m_fpValue = inst->dst();
break;
case LdThis:
m_thisAvailable = true;
break;
default:
break;
}
if (inst->modifiesStack()) {
m_spValue = inst->modifiedStkPtr();
}
// update the CSE table
if (m_enableCse && inst->canCSE()) {
cseInsert(inst);
}
// if the instruction kills any of its sources, remove them from the
// CSE table
if (inst->killsSources()) {
for (int i = 0; i < inst->numSrcs(); ++i) {
if (inst->killsSource(i)) {
cseKill(inst->src(i));
}
}
}
}
