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[ConstraintSystem] NFC: Associate transitive binding inference with PotentialBindings

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This commit is contained in:
Pavel Yaskevich
2020-07-01 14:31:51 -07:00
parent fa553ab83d
commit 8df19d2c87
2 changed files with 36 additions and 34 deletions
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37
lib/Sema/CSBindings.cpp
View File

@@ -21,36 +21,37 @@
using namespace swift;
using namespace constraints;
void ConstraintSystem::inferTransitiveSupertypeBindings(
const llvm::SmallDenseMap<TypeVariableType *, PotentialBindings>
&inferredBindings,
PotentialBindings &bindings) {
auto *typeVar = bindings.TypeVar;
void ConstraintSystem::PotentialBindings::inferTransitiveBindings(
ConstraintSystem &cs,
const llvm::SmallDenseMap<TypeVariableType *,
ConstraintSystem::PotentialBindings>
&inferredBindings) {
using BindingKind = ConstraintSystem::AllowedBindingKind;
llvm::SmallVector<Constraint *, 4> subtypeOf;
// First, let's collect all of the `subtype` constraints associated
// with this type variable.
llvm::copy_if(bindings.Sources, std::back_inserter(subtypeOf),
llvm::copy_if(Sources, std::back_inserter(subtypeOf),
[&](const Constraint *constraint) -> bool {
if (constraint->getKind() != ConstraintKind::Subtype)
return false;
auto rhs = simplifyType(constraint->getSecondType());
return rhs->getAs<TypeVariableType>() == typeVar;
auto rhs = cs.simplifyType(constraint->getSecondType());
return rhs->getAs<TypeVariableType>() == TypeVar;
});
if (subtypeOf.empty())
return;
// We need to make sure that there are no duplicate bindings in the
// set, other we'll produce multiple identical solutions.
// set, otherwise solver would produce multiple identical solutions.
llvm::SmallPtrSet<CanType, 4> existingTypes;
for (const auto &binding : bindings.Bindings)
for (const auto &binding : Bindings)
existingTypes.insert(binding.BindingType->getCanonicalType());
for (auto *constraint : subtypeOf) {
auto *tv =
simplifyType(constraint->getFirstType())->getAs<TypeVariableType>();
cs.simplifyType(constraint->getFirstType())->getAs<TypeVariableType>();
if (!tv)
continue;
@@ -63,8 +64,8 @@ void ConstraintSystem::inferTransitiveSupertypeBindings(
// either be Exact or Supertypes in order for it to make sense
// to add Supertype bindings based on the relationship between
// our type variables.
if (binding.Kind != AllowedBindingKind::Exact &&
binding.Kind != AllowedBindingKind::Supertypes)
if (binding.Kind != BindingKind::Exact &&
binding.Kind != BindingKind::Supertypes)
continue;
auto type = binding.BindingType;
@@ -75,16 +76,16 @@ void ConstraintSystem::inferTransitiveSupertypeBindings(
if (!existingTypes.insert(type->getCanonicalType()).second)
continue;
if (ConstraintSystem::typeVarOccursInType(typeVar, type))
if (ConstraintSystem::typeVarOccursInType(TypeVar, type))
continue;
bindings.addPotentialBinding(
binding.withSameSource(type, AllowedBindingKind::Supertypes));
addPotentialBinding(
binding.withSameSource(type, BindingKind::Supertypes));
}
// Infer transitive protocol requirements.
for (auto *protocol : relatedBindings->getSecond().Protocols) {
bindings.Protocols.push_back(protocol);
Protocols.push_back(protocol);
}
}
}
@@ -113,7 +114,7 @@ ConstraintSystem::determineBestBindings() {
auto &bindings = cachedBindings->getSecond();
inferTransitiveSupertypeBindings(cache, bindings);
bindings.inferTransitiveBindings(*this, cache);
if (isDebugMode()) {
bindings.dump(typeVar, llvm::errs(), solverState->depth * 2);

33
lib/Sema/ConstraintSystem.h
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@@ -4557,6 +4557,23 @@ private:
/// if it has only concrete types or would resolve a closure.
bool favoredOverDisjunction(Constraint *disjunction) const;
/// Detect `subtype` relationship between two type variables and
/// attempt to infer supertype bindings transitively e.g.
///
/// Given A <: T1 <: T2 transitively A <: T2
///
/// Which gives us a new (superclass A) binding for T2 as well as T1.
///
/// \param cs The constraint system this type variable is associated with.
///
/// \param inferredBindings The set of all bindings inferred for type
/// variables in the workset.
void inferTransitiveBindings(
ConstraintSystem &cs,
const llvm::SmallDenseMap<TypeVariableType *,
ConstraintSystem::PotentialBindings>
&inferredBindings);
void dump(llvm::raw_ostream &out,
unsigned indent = 0) const LLVM_ATTRIBUTE_USED {
out.indent(indent);
@@ -4625,22 +4642,6 @@ private:
bool &addOptionalSupertypeBindings) const;
PotentialBindings getPotentialBindings(TypeVariableType *typeVar) const;
/// Detect `subtype` relationship between two type variables and
/// attempt to infer supertype bindings transitively e.g.
///
/// Given A <: T1 <: T2 transitively A <: T2
///
/// Which gives us a new (superclass A) binding for T2 as well as T1.
///
/// \param inferredBindings The set of all bindings inferred for type
/// variables in the workset.
/// \param bindings The type variable we aim to infer new supertype
/// bindings for.
void inferTransitiveSupertypeBindings(
const llvm::SmallDenseMap<TypeVariableType *, PotentialBindings>
&inferredBindings,
PotentialBindings &bindings);
private:
/// Add a constraint to the constraint system.
SolutionKind addConstraintImpl(ConstraintKind kind, Type first, Type second,