void ExpressionList::optimize(AnalysisResultConstPtr ar) {
bool changed = false;
size_t i = m_exps.size();
if (m_kind != ListKindParam) {
size_t skip = m_kind == ListKindLeft ? 0 : i - 1;
while (i--) {
if (i != skip) {
ExpressionPtr &e = m_exps[i];
if (!e || e->getContainedEffects() == NoEffect) {
removeElement(i);
changed = true;
} else if (e->is(KindOfExpressionList)) {
ExpressionListPtr el(static_pointer_cast<ExpressionList>(e));
removeElement(i);
for (size_t j = el->getCount(); j--; ) {
insertElement((*el)[j], i);
}
changed = true;
} else if (e->getLocalEffects() == NoEffect) {
e = e->unneeded();
// changed already handled by unneeded
}
}
}
if (m_exps.size() == 1) {
m_kind = ListKindWrapped;
} else if (m_kind == ListKindLeft && m_exps[0]->isScalar()) {
ExpressionPtr e = m_exps[0];
removeElement(0);
addElement(e);
m_kind = ListKindWrapped;
}
} else {
if (hasContext(UnsetContext) &&
ar->getPhase() >= AnalysisResult::PostOptimize) {
while (i--) {
ExpressionPtr &e = m_exps[i];
if (e->is(Expression::KindOfSimpleVariable)) {
SimpleVariablePtr var = dynamic_pointer_cast<SimpleVariable>(e);
if (var->checkUnused()) {
const std::string &name = var->getName();
VariableTablePtr variables = getScope()->getVariables();
if (!variables->isNeeded(name)) {
removeElement(i);
changed = true;
}
}
}
}
}
}
if (changed) {
getScope()->addUpdates(BlockScope::UseKindCaller);
}
}
bool Expression::CheckNeeded(ExpressionPtr variable, ExpressionPtr value) {
// if the value may involve object, consider the variable as "needed"
// so that objects are not destructed prematurely.
bool needed = true;
if (value) needed = CheckNeededRHS(value);
if (variable->is(Expression::KindOfSimpleVariable)) {
auto var = dynamic_pointer_cast<SimpleVariable>(variable);
const std::string &name = var->getName();
VariableTablePtr variables = var->getScope()->getVariables();
if (needed) {
variables->addNeeded(name);
} else {
needed = variables->isNeeded(name);
}
}
return needed;
}
void ExpressionList::optimize(AnalysisResultConstPtr ar) {
bool changed = false;
size_t i = m_exps.size();
if (m_kind != ListKindParam) {
size_t skip = m_kind == ListKindLeft ? 0 : i - 1;
while (i--) {
if (i != skip) {
ExpressionPtr &e = m_exps[i];
if (!e || (e->getContainedEffects() == NoEffect && !e->isNoRemove())) {
removeElement(i);
changed = true;
} else if (e->is(KindOfExpressionList)) {
ExpressionListPtr el(static_pointer_cast<ExpressionList>(e));
removeElement(i);
for (size_t j = el->getCount(); j--; ) {
insertElement((*el)[j], i);
}
changed = true;
} else if (e->getLocalEffects() == NoEffect) {
e = e->unneeded();
// changed already handled by unneeded
}
}
}
if (m_exps.size() == 1) {
// don't convert an exp-list with type assertions to
// a ListKindWrapped
if (!isNoRemove()) {
m_kind = ListKindWrapped;
}
} else if (m_kind == ListKindLeft && m_exps[0]->isScalar()) {
ExpressionPtr e = m_exps[0];
removeElement(0);
addElement(e);
m_kind = ListKindWrapped;
}
} else {
bool isUnset = hasContext(UnsetContext) &&
// This used to be gated on ar->getPhase() >= PostOptimize
false;
int isGlobal = -1;
while (i--) {
ExpressionPtr &e = m_exps[i];
if (isUnset) {
if (e->is(Expression::KindOfSimpleVariable)) {
SimpleVariablePtr var = dynamic_pointer_cast<SimpleVariable>(e);
if (var->checkUnused()) {
const std::string &name = var->getName();
VariableTablePtr variables = getScope()->getVariables();
if (!variables->isNeeded(name)) {
removeElement(i);
changed = true;
}
}
}
} else {
bool global = e && (e->getContext() & Declaration) == Declaration;
if (isGlobal < 0) {
isGlobal = global;
} else {
always_assert(isGlobal == global);
}
if (isGlobal && e->isScalar()) {
removeElement(i);
changed = true;
}
}
}
}
if (changed) {
getScope()->addUpdates(BlockScope::UseKindCaller);
}
}