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[Runtime] Disable prespecialized metadata if we have overridden images. #72873

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Merged
merged 1 commit into from
Apr 9, 2024
Merged

[Runtime] Disable prespecialized metadata if we have overridden images. #72873

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1 change: 1 addition & 0 deletions include/swift/Runtime/LibPrespecialized.h
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ struct LibPrespecializedData {
const LibPrespecializedData<InProcess> *getLibPrespecializedData();
Metadata *getLibPrespecializedMetadata(const TypeContextDescriptor *description,
const void *const *arguments);
void libPrespecializedImageLoaded();

} // namespace swift

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19 changes: 18 additions & 1 deletion stdlib/public/runtime/LibPrespecialized.cpp
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Expand Up @@ -16,6 +16,8 @@
#include "swift/Runtime/EnvironmentVariables.h"
#include "swift/Runtime/Metadata.h"

#include <atomic>

#if SWIFT_STDLIB_HAS_DLADDR && __has_include(<dlfcn.h>)
#include <dlfcn.h>
#define USE_DLOPEN 1
Expand All @@ -27,6 +29,8 @@

using namespace swift;

static std::atomic<bool> disablePrespecializedMetadata = false;

static const LibPrespecializedData<InProcess> *findLibPrespecialized() {
if (!runtime::environment::SWIFT_DEBUG_ENABLE_LIB_PRESPECIALIZED())
return nullptr;
Expand Down Expand Up @@ -91,10 +95,23 @@ static bool hasNonTypeGenericArguments(const TypeContextDescriptor *description)

static bool disableForValidation = false;

void
swift::libPrespecializedImageLoaded() {
#if DYLD_GET_SWIFT_PRESPECIALIZED_DATA_DEFINED
// A newly loaded image might have caused us to load images that are
// overriding images in the shared cache. If we do that, turn off
// prespecialized metadata.
if (dyld_shared_cache_some_image_overridden())
disablePrespecializedMetadata.store(true, std::memory_order_release);
#endif
}

Metadata *
swift::getLibPrespecializedMetadata(const TypeContextDescriptor *description,
const void *const *arguments) {
if (disableForValidation)
if (SWIFT_UNLIKELY(
disableForValidation
|| disablePrespecializedMetadata.load(std::memory_order_acquire)))
return nullptr;

auto *data = getLibPrespecializedData();
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3 changes: 3 additions & 0 deletions stdlib/public/runtime/MetadataLookup.cpp
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Expand Up @@ -29,6 +29,7 @@
#include "swift/Runtime/Debug.h"
#include "swift/Runtime/EnvironmentVariables.h"
#include "swift/Runtime/HeapObject.h"
#include "swift/Runtime/LibPrespecialized.h"
#include "swift/Runtime/Metadata.h"
#include "swift/Strings.h"
#include "swift/Threading/Mutex.h"
Expand Down Expand Up @@ -347,6 +348,8 @@ void swift::addImageTypeMetadataRecordBlockCallbackUnsafe(
assert(recordsSize % sizeof(TypeMetadataRecord) == 0
&& "weird-sized type metadata section?!");

libPrespecializedImageLoaded();

// If we have a section, enqueue the type metadata for lookup.
auto recordBytes = reinterpret_cast<const char *>(records);
auto recordsBegin
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