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Solver: Keep track of a solution's score as we're computing it.

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No functionality change here; just staging for some future optimizations.


Swift SVN r11028
This commit is contained in:
Doug Gregor
2013-12-09 17:12:07 +00:00
parent ac7ee4ba59
commit 79f8175e0b
8 changed files with 209 additions and 83 deletions
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46
lib/Sema/ConstraintSystem.cpp
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@@ -69,9 +69,51 @@ void ConstraintSystem::mergeEquivalenceClasses(TypeVariableType *typeVar1,
}
}
void ConstraintSystem::assignFixedType(TypeVariableType *typeVar, Type type) {
void ConstraintSystem::assignFixedType(TypeVariableType *typeVar, Type type,
bool updateScore) {
typeVar->getImpl().assignFixedType(type, getSavedBindings());
if (updateScore && !type->is<TypeVariableType>()) {
// If this type variable represents a literal, check whether we picked the
// default literal type. First, find the corresponding protocol.
ProtocolDecl *literalProtocol = nullptr;
if (CG) {
// If we have the constraint graph, we can check all type variables in
// the equivalence class. This is the More Correct path.
// FIXME: Eliminate the less-correct path.
auto typeVarRep = getRepresentative(typeVar);
for (auto tv : (*CG)[typeVarRep].getEquivalenceClass()) {
auto locator = tv->getImpl().getLocator();
if (!locator || !locator->getPath().empty())
continue;
auto anchor = locator->getAnchor();
if (!anchor)
continue;
literalProtocol = TC.getLiteralProtocol(anchor);
if (literalProtocol)
break;
}
} else {
// FIXME: This is the less-correct path.
auto locator = typeVar->getImpl().getLocator();
if (locator && locator->getPath().empty() && locator->getAnchor()) {
literalProtocol = TC.getLiteralProtocol(locator->getAnchor());
}
}
// If the protocol has a default type, check it.
if (literalProtocol) {
if (auto defaultType = TC.getDefaultType(literalProtocol, DC)) {
// Check whether the nominal types match. This makes sure that we
// properly handle Slice vs. Slice<T>.
if (defaultType->getAnyNominal() != type->getAnyNominal())
increaseScore(SK_NonDefaultLiteral);
}
}
}
// Notify the constraint graph.
if (CG) {
CG->bindTypeVariable(typeVar, type);