const Metadata *
swift::_searchConformancesByMangledTypeName(const llvm::StringRef typeName) {
auto &C = Conformances.get();
const Metadata *foundMetadata = nullptr;
pthread_mutex_lock(&C.SectionsToScanLock);
unsigned sectionIdx = 0;
unsigned endSectionIdx = C.SectionsToScan.size();
for (; sectionIdx < endSectionIdx; ++sectionIdx) {
auto §ion = C.SectionsToScan[sectionIdx];
for (const auto &record : section) {
if (auto metadata = record.getCanonicalTypeMetadata())
foundMetadata = _matchMetadataByMangledTypeName(typeName, metadata, nullptr);
else if (auto pattern = record.getGenericPattern())
foundMetadata = _matchMetadataByMangledTypeName(typeName, nullptr, pattern);
if (foundMetadata != nullptr)
break;
}
if (foundMetadata != nullptr)
break;
}
pthread_mutex_unlock(&C.SectionsToScanLock);
return foundMetadata;
}
const Metadata *
swift::_searchConformancesByMangledTypeName(const llvm::StringRef typeName) {
auto &C = Conformances.get();
const Metadata *foundMetadata = nullptr;
ScopedLock guard(C.SectionsToScanLock);
unsigned sectionIdx = 0;
unsigned endSectionIdx = C.SectionsToScan.size();
for (; sectionIdx < endSectionIdx; ++sectionIdx) {
auto §ion = C.SectionsToScan[sectionIdx];
for (const auto &record : section) {
if (auto metadata = record.getCanonicalTypeMetadata())
foundMetadata = _matchMetadataByMangledTypeName(typeName, metadata, nullptr);
else if (auto ntd = record.getNominalTypeDescriptor())
foundMetadata = _matchMetadataByMangledTypeName(typeName, nullptr, ntd);
if (foundMetadata != nullptr)
break;
}
if (foundMetadata != nullptr)
break;
}
return foundMetadata;
}
/// Search the witness table in the ConformanceCache. \returns a pair of the
/// WitnessTable pointer and a boolean value True if a definitive value is
/// found. \returns false if the type or its superclasses were not found in
/// the cache.
static
std::pair<const WitnessTable *, bool>
searchInConformanceCache(const Metadata *type,
const ProtocolDescriptor *protocol,
ConformanceCacheEntry *&foundEntry) {
auto &C = Conformances.get();
auto origType = type;
foundEntry = nullptr;
recur_inside_cache_lock:
// See if we have a cached conformance. Try the specific type first.
{
// Check if the type-protocol entry exists in the cache entry that we found.
if (auto *Value = C.findCached(type, protocol)) {
if (Value->isSuccessful())
return std::make_pair(Value->getWitnessTable(), true);
// If we're still looking up for the original type, remember that
// we found an exact match.
if (type == origType)
foundEntry = Value;
// If we got a cached negative response, check the generation number.
if (Value->getFailureGeneration() == C.SectionsToScan.size()) {
// We found an entry with a negative value.
return std::make_pair(nullptr, true);
}
}
}
{
// For generic and resilient types, nondependent conformances
// are keyed by the nominal type descriptor rather than the
// metadata, so try that.
auto *description = type->getNominalTypeDescriptor().get();
// Hash and lookup the type-protocol pair in the cache.
if (auto *Value = C.findCached(description, protocol)) {
if (Value->isSuccessful())
return std::make_pair(Value->getWitnessTable(), true);
// We don't try to cache negative responses for generic
// patterns.
}
}
// If the type is a class, try its superclass.
if (const ClassMetadata *classType = type->getClassObject()) {
if (classHasSuperclass(classType)) {
type = swift_getObjCClassMetadata(classType->SuperClass);
goto recur_inside_cache_lock;
}
}
// We did not find an entry.
return std::make_pair(nullptr, false);
}
static const TypeContextDescriptor *
_findNominalTypeDescriptor(Demangle::NodePointer node) {
const TypeContextDescriptor *foundNominal = nullptr;
auto &T = TypeMetadataRecords.get();
auto mangledName = Demangle::mangleNode(node);
// Look for an existing entry.
// Find the bucket for the metadata entry.
if (auto Value = T.NominalCache.find(mangledName))
return Value->getDescription();
// Check type metadata records
T.SectionsToScanLock.withLock([&] {
foundNominal = _searchTypeMetadataRecords(T, node);
});
// Check protocol conformances table. Note that this has no support for
// resolving generic types yet.
if (!foundNominal)
foundNominal = _searchConformancesByMangledTypeName(node);
if (foundNominal) {
T.NominalCache.getOrInsert(mangledName, foundNominal);
}
return foundNominal;
}
static const TypeContextDescriptor *
_findNominalTypeDescriptor(Demangle::NodePointer node,
Demangle::Demangler &Dem) {
const TypeContextDescriptor *foundNominal = nullptr;
auto &T = TypeMetadataRecords.get();
// If we have a symbolic reference to a context, resolve it immediately.
NodePointer symbolicNode = node;
if (symbolicNode->getKind() == Node::Kind::Type)
symbolicNode = symbolicNode->getChild(0);
if (symbolicNode->getKind() == Node::Kind::SymbolicReference)
return cast<TypeContextDescriptor>(
(const ContextDescriptor *)symbolicNode->getIndex());
auto mangledName =
Demangle::mangleNode(node,
[&](const void *context) -> NodePointer {
return _buildDemanglingForContext(
(const ContextDescriptor *) context,
{}, false, Dem);
});
// Look for an existing entry.
// Find the bucket for the metadata entry.
if (auto Value = T.NominalCache.find(mangledName))
return Value->getDescription();
// Check type metadata records
foundNominal = _searchTypeMetadataRecords(T, node);
// Check protocol conformances table. Note that this has no support for
// resolving generic types yet.
if (!foundNominal)
foundNominal = _searchConformancesByMangledTypeName(node);
if (foundNominal) {
T.NominalCache.getOrInsert(mangledName, foundNominal);
}
return foundNominal;
}
static const Metadata *
_typeByMangledName(const llvm::StringRef typeName) {
const Metadata *foundMetadata = nullptr;
auto &T = TypeMetadataRecords.get();
// Look for an existing entry.
// Find the bucket for the metadata entry.
if (auto Value = T.Cache.find(typeName))
return Value->getMetadata();
// Check type metadata records
pthread_mutex_lock(&T.SectionsToScanLock);
foundMetadata = _searchTypeMetadataRecords(T, typeName);
pthread_mutex_unlock(&T.SectionsToScanLock);
// Check protocol conformances table. Note that this has no support for
// resolving generic types yet.
if (!foundMetadata)
foundMetadata = _searchConformancesByMangledTypeName(typeName);
if (foundMetadata) {
T.Cache.getOrInsert(typeName, foundMetadata);
}
#if SWIFT_OBJC_INTEROP
// Check for ObjC class
// FIXME does this have any value? any ObjC class with a Swift name
// should already be registered as a Swift type.
if (foundMetadata == nullptr) {
std::string prefixedName("_Tt" + typeName.str());
foundMetadata = reinterpret_cast<ClassMetadata *>
(objc_lookUpClass(prefixedName.c_str()));
}
#endif
return foundMetadata;
}
static BoxPair::Return _swift_allocBox_(const Metadata *type) {
// Get the heap metadata for the box.
auto &B = Boxes.get();
const void *typeArg = type;
auto entry = B.findOrAdd(&typeArg, 1, [&]() -> BoxCacheEntry* {
// Create a new entry for the box.
auto entry = BoxCacheEntry::allocate(B.getAllocator(), &typeArg, 1, 0);
auto metadata = entry->getData();
metadata->Offset = GenericBoxHeapMetadata::getHeaderOffset(type);
metadata->BoxedType = type;
return entry;
});
auto metadata = entry->getData();
// Allocate and project the box.
auto allocation = swift_allocObject(metadata, metadata->getAllocSize(),
metadata->getAllocAlignMask());
auto projection = metadata->project(allocation);
return BoxPair{allocation, projection};
}
void
swift::swift_registerTypeMetadataRecords(const TypeMetadataRecord *begin,
const TypeMetadataRecord *end) {
auto &T = TypeMetadataRecords.get();
_registerTypeMetadataRecords(T, begin, end);
}
const WitnessTable *
swift::swift_conformsToProtocol(const Metadata *type,
const ProtocolDescriptor *protocol) {
auto &C = Conformances.get();
auto origType = type;
unsigned numSections = 0;
ConformanceCacheEntry *foundEntry;
recur:
// See if we have a cached conformance. The ConcurrentMap data structure
// allows us to insert and search the map concurrently without locking.
// We do lock the slow path because the SectionsToScan data structure is not
// concurrent.
auto FoundConformance = searchInConformanceCache(type, protocol, foundEntry);
// The negative answer does not always mean that there is no conformance,
// unless it is an exact match on the type. If it is not an exact match,
// it may mean that all of the superclasses do not have this conformance,
// but the actual type may still have this conformance.
if (FoundConformance.second) {
if (FoundConformance.first || foundEntry)
return FoundConformance.first;
}
// If we didn't have an up-to-date cache entry, scan the conformance records.
C.SectionsToScanLock.lock();
unsigned failedGeneration = ConformanceCacheGeneration;
// If we have no new information to pull in (and nobody else pulled in
// new information while we waited on the lock), we're done.
if (C.SectionsToScan.size() == numSections) {
if (failedGeneration != ConformanceCacheGeneration) {
// Someone else pulled in new conformances while we were waiting.
// Start over with our newly-populated cache.
C.SectionsToScanLock.unlock();
type = origType;
goto recur;
}
// Save the failure for this type-protocol pair in the cache.
C.cacheFailure(type, protocol);
C.SectionsToScanLock.unlock();
return nullptr;
}
// Update the last known number of sections to scan.
numSections = C.SectionsToScan.size();
// Scan only sections that were not scanned yet.
unsigned sectionIdx = foundEntry ? foundEntry->getFailureGeneration() : 0;
unsigned endSectionIdx = C.SectionsToScan.size();
for (; sectionIdx < endSectionIdx; ++sectionIdx) {
auto §ion = C.SectionsToScan[sectionIdx];
// Eagerly pull records for nondependent witnesses into our cache.
for (const auto &record : section) {
// If the record applies to a specific type, cache it.
if (auto metadata = record.getCanonicalTypeMetadata()) {
auto P = record.getProtocol();
// Look for an exact match.
if (protocol != P)
continue;
if (!isRelatedType(type, metadata, /*isMetadata=*/true))
continue;
// Store the type-protocol pair in the cache.
auto witness = record.getWitnessTable(metadata);
if (witness) {
C.cacheSuccess(metadata, P, witness);
} else {
C.cacheFailure(metadata, P);
}
// If the record provides a nondependent witness table for all instances
// of a generic type, cache it for the generic pattern.
// TODO: "Nondependent witness table" probably deserves its own flag.
// An accessor function might still be necessary even if the witness table
// can be shared.
} else if (record.getTypeKind()
== TypeMetadataRecordKind::UniqueNominalTypeDescriptor
&& record.getConformanceKind()
== ProtocolConformanceReferenceKind::WitnessTable) {
auto R = record.getNominalTypeDescriptor();
auto P = record.getProtocol();
// Look for an exact match.
if (protocol != P)
continue;
if (!isRelatedType(type, R, /*isMetadata=*/false))
continue;
// Store the type-protocol pair in the cache.
C.cacheSuccess(R, P, record.getStaticWitnessTable());
}
}
}
++ConformanceCacheGeneration;
C.SectionsToScanLock.unlock();
// Start over with our newly-populated cache.
type = origType;
goto recur;
}
void
swift::swift_registerProtocolConformances(const ProtocolConformanceRecord *begin,
const ProtocolConformanceRecord *end){
auto &C = Conformances.get();
_registerProtocolConformances(C, begin, end);
}
Laziness()
: total([&]{ return first.get()+ second.get(); }, total.depends(first).depends(second))
{}
/// Search the witness table in the ConformanceCache. \returns a pair of the
/// WitnessTable pointer and a boolean value True if a definitive value is
/// found. \returns false if the type or its superclasses were not found in
/// the cache.
static
std::pair<const WitnessTable *, bool>
searchInConformanceCache(const Metadata *type,
const ProtocolDescriptor *protocol,
ConformanceCacheEntry *&foundEntry) {
auto &C = Conformances.get();
auto origType = type;
foundEntry = nullptr;
recur_inside_cache_lock:
// See if we have a cached conformance. Try the specific type first.
// Hash and lookup the type-protocol pair in the cache.
size_t hash = hashTypeProtocolPair(type, protocol);
ConcurrentList<ConformanceCacheEntry> &Bucket =
C.Cache.findOrAllocateNode(hash);
// Check if the type-protocol entry exists in the cache entry that we found.
for (auto &Entry : Bucket) {
if (!Entry.matches(type, protocol)) continue;
if (Entry.isSuccessful()) {
return std::make_pair(Entry.getWitnessTable(), true);
}
if (type == origType)
foundEntry = &Entry;
// If we got a cached negative response, check the generation number.
if (Entry.getFailureGeneration() == C.SectionsToScan.size()) {
// We found an entry with a negative value.
return std::make_pair(nullptr, true);
}
}
// If the type is generic, see if there's a shared nondependent witness table
// for its instances.
if (auto generic = type->getGenericPattern()) {
// Hash and lookup the type-protocol pair in the cache.
size_t hash = hashTypeProtocolPair(generic, protocol);
ConcurrentList<ConformanceCacheEntry> &Bucket =
C.Cache.findOrAllocateNode(hash);
for (auto &Entry : Bucket) {
if (!Entry.matches(generic, protocol)) continue;
if (Entry.isSuccessful()) {
return std::make_pair(Entry.getWitnessTable(), true);
}
// We don't try to cache negative responses for generic
// patterns.
}
}
// If the type is a class, try its superclass.
if (const ClassMetadata *classType = type->getClassObject()) {
if (classHasSuperclass(classType)) {
type = swift_getObjCClassMetadata(classType->SuperClass);
goto recur_inside_cache_lock;
}
}
// We did not find an entry.
return std::make_pair(nullptr, false);
}
const WitnessTable *
swift::swift_conformsToProtocol(const Metadata * const type,
const ProtocolDescriptor *protocol) {
auto &C = Conformances.get();
// See if we have a cached conformance. The ConcurrentMap data structure
// allows us to insert and search the map concurrently without locking.
// We do lock the slow path because the SectionsToScan data structure is not
// concurrent.
auto FoundConformance = searchInConformanceCache(type, protocol);
// If the result (positive or negative) is authoritative, return it.
if (FoundConformance.isAuthoritative)
return FoundConformance.witnessTable;
auto failureEntry = FoundConformance.failureEntry;
// No up-to-date cache entry found.
// Acquire the lock so we can scan conformance records.
ScopedLock guard(C.SectionsToScanLock);
// The world may have changed while we waited for the lock.
// If we found an out-of-date negative cache entry before
// acquiring the lock, make sure the entry is still negative and out of date.
// If we found no entry before acquiring the lock, search the cache again.
if (failureEntry) {
if (failureEntry->isSuccessful()) {
// Somebody else found a conformance.
return failureEntry->getWitnessTable();
}
if (failureEntry->getFailureGeneration() == C.SectionsToScan.size()) {
// Somebody else brought the negative cache entry up to date.
return nullptr;
}
}
else {
FoundConformance = searchInConformanceCache(type, protocol);
if (FoundConformance.isAuthoritative) {
// Somebody else found a conformance or cached an up-to-date failure.
return FoundConformance.witnessTable;
}
failureEntry = FoundConformance.failureEntry;
}
// We are now caught up after acquiring the lock.
// Prepare to scan conformance records.
// Scan only sections that were not scanned yet.
// If we found an out-of-date negative cache entry,
// we need not to re-scan the sections that it covers.
unsigned startSectionIdx =
failureEntry ? failureEntry->getFailureGeneration() : 0;
unsigned endSectionIdx = C.SectionsToScan.size();
// If there are no unscanned sections outstanding
// then we can cache failure and give up now.
if (startSectionIdx == endSectionIdx) {
C.cacheFailure(type, protocol);
return nullptr;
}
// Really scan conformance records.
for (unsigned sectionIdx = startSectionIdx;
sectionIdx < endSectionIdx;
++sectionIdx) {
auto §ion = C.SectionsToScan[sectionIdx];
// Eagerly pull records for nondependent witnesses into our cache.
for (const auto &record : section) {
// If the record applies to a specific type, cache it.
if (auto metadata = record.getCanonicalTypeMetadata()) {
auto P = record.getProtocol();
// Look for an exact match.
if (protocol != P)
continue;
if (!isRelatedType(type, metadata, /*candidateIsMetadata=*/true))
continue;
// Store the type-protocol pair in the cache.
auto witness = record.getWitnessTable(metadata);
if (witness) {
C.cacheSuccess(metadata, P, witness);
} else {
C.cacheFailure(metadata, P);
}
// TODO: "Nondependent witness table" probably deserves its own flag.
// An accessor function might still be necessary even if the witness table
// can be shared.
} else if (record.getTypeKind()
== TypeMetadataRecordKind::UniqueNominalTypeDescriptor) {
auto R = record.getNominalTypeDescriptor();
auto P = record.getProtocol();
// Look for an exact match.
if (protocol != P)
continue;
if (!isRelatedType(type, R, /*candidateIsMetadata=*/false))
continue;
// Store the type-protocol pair in the cache.
switch (record.getConformanceKind()) {
case ProtocolConformanceReferenceKind::WitnessTable:
// If the record provides a nondependent witness table for all
// instances of a generic type, cache it for the generic pattern.
C.cacheSuccess(R, P, record.getStaticWitnessTable());
break;
case ProtocolConformanceReferenceKind::WitnessTableAccessor:
// If the record provides a dependent witness table accessor,
// cache the result for the instantiated type metadata.
C.cacheSuccess(type, P, record.getWitnessTable(type));
break;
}
}
}
}
// Conformance scan is complete.
// Search the cache once more, and this time update the cache if necessary.
FoundConformance = searchInConformanceCache(type, protocol);
if (FoundConformance.isAuthoritative) {
return FoundConformance.witnessTable;
} else {
C.cacheFailure(type, protocol);
return nullptr;
}
}
/// Search for a witness table in the ConformanceCache.
static
ConformanceCacheResult
searchInConformanceCache(const Metadata *type,
const ProtocolDescriptor *protocol) {
auto &C = Conformances.get();
auto origType = type;
ConformanceCacheEntry *failureEntry = nullptr;
recur:
{
// Try the specific type first.
if (auto *Value = C.findCached(type, protocol)) {
if (Value->isSuccessful()) {
// Found a conformance on the type or some superclass. Return it.
return ConformanceCacheResult::cachedSuccess(Value->getWitnessTable());
}
// Found a negative cache entry.
bool isAuthoritative;
if (type == origType) {
// This negative cache entry is for the original query type.
// Remember it so it can be returned later.
failureEntry = Value;
// An up-to-date entry for the original type is authoritative.
isAuthoritative = true;
} else {
// An up-to-date cached failure for a superclass of the type is not
// authoritative: there may be a still-undiscovered conformance
// for the original query type.
isAuthoritative = false;
}
// Check if the negative cache entry is up-to-date.
// FIXME: Using SectionsToScan.size() outside SectionsToScanLock
// is undefined.
if (Value->getFailureGeneration() == C.SectionsToScan.size()) {
// Negative cache entry is up-to-date. Return failure along with
// the original query type's own cache entry, if we found one.
// (That entry may be out of date but the caller still has use for it.)
return ConformanceCacheResult::cachedFailure(failureEntry,
isAuthoritative);
}
// Negative cache entry is out-of-date.
// Continue searching for a better result.
}
}
{
// For generic and resilient types, nondependent conformances
// are keyed by the nominal type descriptor rather than the
// metadata, so try that.
const auto description = type->getNominalTypeDescriptor().get();
// Hash and lookup the type-protocol pair in the cache.
if (auto *Value = C.findCached(description, protocol)) {
if (Value->isSuccessful())
return ConformanceCacheResult::cachedSuccess(Value->getWitnessTable());
// We don't try to cache negative responses for generic
// patterns.
}
}
// If the type is a class, try its superclass.
if (const ClassMetadata *classType = type->getClassObject()) {
if (classHasSuperclass(classType)) {
type = swift_getObjCClassMetadata(classType->SuperClass);
goto recur;
}
}
// We did not find an up-to-date cache entry.
// If we found an out-of-date entry for the original query type then
// return it (non-authoritatively). Otherwise return a cache miss.
if (failureEntry)
return ConformanceCacheResult::cachedFailure(failureEntry, false);
else
return ConformanceCacheResult::cacheMiss();
}