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[ConstraintSystem] Simplify addOverloadSet

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- Remove whole disjunction favoring which has no effect;
- Avoid creating separate disjunction for "inner" choices,
  which is going to be flattened later anyway.
This commit is contained in:
Pavel Yaskevich
2019-03-08 18:25:29 -08:00
parent 7d4b72ffb5
commit c2590c0dec
2 changed files with 22 additions and 40 deletions
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52
lib/Sema/ConstraintSystem.cpp
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@@ -1490,55 +1490,39 @@ void ConstraintSystem::addOverloadSet(Type boundType,
return;
}
auto recordChoice = [&](SmallVectorImpl<Constraint *> &choices,
const OverloadChoice &choice,
bool isFavored = false) {
auto *constraint = Constraint::createBindOverload(*this, boundType, choice,
useDC, locator);
if (isFavored)
constraint->setFavored();
choices.push_back(constraint);
};
SmallVector<Constraint *, 4> overloads;
// As we do for other favored constraints, if a favored overload has been
// specified, let it be the first term in the disjunction.
if (favoredChoice) {
auto bindOverloadConstraint =
Constraint::createBindOverload(*this,
boundType,
*favoredChoice,
useDC,
locator);
assert((!favoredChoice->isDecl() ||
!favoredChoice->getDecl()->getAttrs().isUnavailable(
getASTContext())) &&
"Cannot make unavailable decl favored!");
bindOverloadConstraint->setFavored();
overloads.push_back(bindOverloadConstraint);
recordChoice(overloads, *favoredChoice, /*isFavored=*/true);
}
for (auto &choice : choices) {
if (favoredChoice && (favoredChoice == &choice))
continue;
overloads.push_back(Constraint::createBindOverload(*this, boundType, choice,
useDC, locator));
recordChoice(overloads, choice);
}
auto innerDisjunction = Constraint::createDisjunction(*this, overloads,
locator, ForgetChoice);
if (outerAlternatives.empty()) {
if (favoredChoice)
innerDisjunction->setFavored();
for (auto &choice : outerAlternatives)
recordChoice(overloads, choice);
addUnsolvedConstraint(innerDisjunction);
return;
}
SmallVector<Constraint *, 4> outerConstraints;
outerConstraints.push_back(innerDisjunction);
innerDisjunction->setFavored();
for (auto choice : outerAlternatives) {
outerConstraints.push_back(Constraint::createBindOverload(
*this, boundType, choice,
useDC, locator));
}
addDisjunctionConstraint(outerConstraints, locator, ForgetChoice, favoredChoice);
addDisjunctionConstraint(overloads, locator, ForgetChoice);
}
/// If we're resolving an overload set with a decl that has special type