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[ConstraintSystem] NFC: Remove ArgumentInfoCollector which was part… #36059

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Merged
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Feb 22, 2021
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[ConstraintSystem] NFC: Remove ArgumentInfoCollector which was part… #36059

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55 changes: 0 additions & 55 deletions include/swift/Sema/ConstraintSystem.h
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Original file line number Diff line number Diff line change
Expand Up @@ -4905,61 +4905,6 @@ class ConstraintSystem {
return getExpressionTooComplex(solutionMemory);
}

// Utility class that can collect information about the type of an
// argument in an apply.
//
// For example, when given a type variable type that represents the
// argument of a function call, it will walk the constraint graph
// finding any concrete types that are reachable through various
// subtype constraints and will also collect all the literal types
// conformed to by the types it finds on the walk.
//
// This makes it possible to get an idea of the kinds of literals
// and types of arguments that are used in the subexpression rooted
// in this argument, which we can then use to make better choices
// for how we partition the operators in a disjunction (in order to
// avoid visiting all the options).
class ArgumentInfoCollector {
ConstraintSystem &CS;
llvm::SetVector<Type> Types;
llvm::SetVector<ProtocolDecl *> LiteralProtocols;

void addType(Type ty) {
assert(!ty->is<TypeVariableType>());
Types.insert(ty);
}

void addLiteralProtocol(ProtocolDecl *proto) {
LiteralProtocols.insert(proto);
}

void walk(Type argType);
void minimizeLiteralProtocols();

public:
ArgumentInfoCollector(ConstraintSystem &cs, FunctionType *fnTy) : CS(cs) {
for (auto &param : fnTy->getParams())
walk(param.getPlainType());

minimizeLiteralProtocols();
}

ArgumentInfoCollector(ConstraintSystem &cs, AnyFunctionType::Param param)
: CS(cs) {
walk(param.getPlainType());
minimizeLiteralProtocols();
}

const llvm::SetVector<Type> &getTypes() const { return Types; }
const llvm::SetVector<ProtocolDecl *> &getLiteralProtocols() const {
return LiteralProtocols;
}

SWIFT_DEBUG_DUMP;
};

bool haveTypeInformationForAllArguments(FunctionType *fnType);

typedef std::function<bool(unsigned index, Constraint *)> ConstraintMatcher;
typedef std::function<void(ArrayRef<Constraint *>, ConstraintMatcher)>
ConstraintMatchLoop;
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224 changes: 0 additions & 224 deletions lib/Sema/CSSolver.cpp
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Expand Up @@ -1611,230 +1611,6 @@ static Constraint *selectBestBindingDisjunction(
return firstBindDisjunction;
}

// For a given type, collect any concrete types or literal
// conformances we can reach by walking the constraint graph starting
// from this point.
//
// For example, if the type is a type variable, we'll walk back
// through the constraints mentioning this type variable and find what
// types are converted to this type along with what literals are
// conformed-to by this type.
void ConstraintSystem::ArgumentInfoCollector::walk(Type argType) {
llvm::SmallSet<TypeVariableType *, 4> visited;
llvm::SmallVector<Type, 4> worklist;
worklist.push_back(argType);

while (!worklist.empty()) {
auto itemTy = worklist.pop_back_val()->getRValueType();

if (!itemTy->is<TypeVariableType>()) {
addType(itemTy);
continue;
}

auto tyvar = itemTy->castTo<TypeVariableType>();
if (auto fixedTy = CS.getFixedType(tyvar)) {
addType(fixedTy);
continue;
}

auto *rep = CS.getRepresentative(tyvar);

// FIXME: This can happen when we have two type variables that are
// subtypes of each other. We would ideally merge those type
// variables somewhere.
if (visited.count(rep))
continue;

visited.insert(rep);

auto constraints = CS.getConstraintGraph().gatherConstraints(
rep, ConstraintGraph::GatheringKind::EquivalenceClass);

for (auto *constraint : constraints) {
switch (constraint->getKind()) {
case ConstraintKind::LiteralConformsTo:
addLiteralProtocol(constraint->getProtocol());
break;

case ConstraintKind::Bind:
case ConstraintKind::Equal: {
auto firstTy = constraint->getFirstType();
auto secondTy = constraint->getSecondType();
if (firstTy->is<TypeVariableType>()) {
auto otherRep =
CS.getRepresentative(firstTy->castTo<TypeVariableType>());
if (otherRep->isEqual(rep))
worklist.push_back(secondTy);
}
if (secondTy->is<TypeVariableType>()) {
auto otherRep =
CS.getRepresentative(secondTy->castTo<TypeVariableType>());
if (otherRep->isEqual(rep))
worklist.push_back(firstTy);
}
break;
}

case ConstraintKind::Subtype:
case ConstraintKind::OperatorArgumentConversion:
case ConstraintKind::ArgumentConversion:
case ConstraintKind::Conversion:
case ConstraintKind::BridgingConversion:
case ConstraintKind::BindParam:
case ConstraintKind::OpaqueUnderlyingType: {
auto secondTy = constraint->getSecondType();
if (secondTy->is<TypeVariableType>()) {
auto otherRep =
CS.getRepresentative(secondTy->castTo<TypeVariableType>());
if (otherRep->isEqual(rep))
worklist.push_back(constraint->getFirstType());
}
break;
}

case ConstraintKind::DynamicTypeOf:
case ConstraintKind::EscapableFunctionOf: {
auto firstTy = constraint->getFirstType();
if (firstTy->is<TypeVariableType>()) {
auto otherRep =
CS.getRepresentative(firstTy->castTo<TypeVariableType>());
if (otherRep->isEqual(rep))
worklist.push_back(constraint->getSecondType());
}
break;
}

case ConstraintKind::OptionalObject: {
// Get the underlying object type.
auto secondTy = constraint->getSecondType();
if (secondTy->is<TypeVariableType>()) {
auto otherRep =
CS.getRepresentative(secondTy->castTo<TypeVariableType>());
if (otherRep->isEqual(rep)) {
// See if we can actually determine what the underlying
// type is.
Type fixedTy;
auto firstTy = constraint->getFirstType();
if (!firstTy->is<TypeVariableType>()) {
fixedTy = firstTy;
} else {
fixedTy = CS.getFixedType(firstTy->castTo<TypeVariableType>());
}
if (fixedTy && fixedTy->getOptionalObjectType())
worklist.push_back(fixedTy->getOptionalObjectType());
}
}
break;
}

case ConstraintKind::KeyPathApplication:
case ConstraintKind::KeyPath: {
auto firstTy = constraint->getFirstType();
if (firstTy->is<TypeVariableType>()) {
auto otherRep =
CS.getRepresentative(firstTy->castTo<TypeVariableType>());
if (otherRep->isEqual(rep))
worklist.push_back(constraint->getThirdType());
}
break;
}

case ConstraintKind::BindToPointerType:
case ConstraintKind::ValueMember:
case ConstraintKind::ValueWitness:
case ConstraintKind::UnresolvedValueMember:
case ConstraintKind::Disjunction:
case ConstraintKind::CheckedCast:
case ConstraintKind::OpenedExistentialOf:
case ConstraintKind::ApplicableFunction:
case ConstraintKind::DynamicCallableApplicableFunction:
case ConstraintKind::BindOverload:
case ConstraintKind::FunctionInput:
case ConstraintKind::FunctionResult:
case ConstraintKind::SelfObjectOfProtocol:
case ConstraintKind::ConformsTo:
case ConstraintKind::Defaultable:
case ConstraintKind::OneWayEqual:
case ConstraintKind::OneWayBindParam:
case ConstraintKind::DefaultClosureType:
break;
}
}
}
}

void ConstraintSystem::ArgumentInfoCollector::minimizeLiteralProtocols() {
if (LiteralProtocols.size() <= 1)
return;

llvm::SmallVector<std::pair<ProtocolDecl *, Type>, 2> candidates;
llvm::SmallVector<ProtocolDecl *, 2> skippedProtocols;

for (auto *protocol : LiteralProtocols) {
if (auto defaultType = TypeChecker::getDefaultType(protocol, CS.DC)) {
candidates.push_back({protocol, defaultType});
continue;
}

// Looks like argument expected to conform to something like
// `ExpressibleByNilLiteral` which doesn't have a default
// type and as a result can't participate in minimalization.
skippedProtocols.push_back(protocol);
}

if (candidates.size() <= 1)
return;

unsigned result = 0;
for (unsigned i = 1, n = candidates.size(); i != n; ++i) {
const auto &candidate = candidates[i];

auto first =
TypeChecker::conformsToProtocol(candidate.second, candidates[result].first,
CS.DC);
auto second =
TypeChecker::conformsToProtocol(candidates[result].second, candidate.first,
CS.DC);
if (first.isInvalid() == second.isInvalid())
return;

if (!first.isInvalid())
result = i;
}

LiteralProtocols.clear();
LiteralProtocols.insert(candidates[result].first);
LiteralProtocols.insert(skippedProtocols.begin(), skippedProtocols.end());
}

void ConstraintSystem::ArgumentInfoCollector::dump() const {
auto &log = llvm::errs();
log << "types:\n";
for (auto type : Types)
type->print(log);
log << "\n";

log << "literal protocols:\n";
for (auto *proto : LiteralProtocols)
proto->print(log);
log << "\n";
}

// Check to see if we know something about the types of all arguments
// in the given function type.
bool ConstraintSystem::haveTypeInformationForAllArguments(
FunctionType *fnType) {
llvm::SetVector<Constraint *> literalConformsTo;
return llvm::all_of(fnType->getParams(),
[&](AnyFunctionType::Param param) -> bool {
ArgumentInfoCollector argInfo(*this, param);
auto countFacts = argInfo.getTypes().size() +
argInfo.getLiteralProtocols().size();
return countFacts > 0;
});
}

Optional<std::pair<Constraint *, unsigned>>
ConstraintSystem::findConstraintThroughOptionals(
TypeVariableType *typeVar, OptionalWrappingDirection optionalDirection,
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