Remove stdlib and runtime dependencies on Foundation and CF

Author: Catfish-Man

include/swift/Runtime/ObjCBridge.h

@@ -79,6 +79,11 @@ namespace swift {
 SWIFT_RUNTIME_EXPORT
 void swift_rootObjCDealloc(HeapObject *self);
 
+// Uses Swift bridging to box a C string into an NSString without introducing
+// a link-time dependency on NSString.
+SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_API
+id swift_stdlib_NSStringFromUTF8(const char *cstr, int len);
+
 }
 
 #endif // SWIFT_OBJC_INTEROP

stdlib/public/core/BridgeObjectiveC.swift

@@ -85,6 +85,22 @@ public protocol _ObjectiveCBridgeable {
 
 #if _runtime(_ObjC)
 
+@_silgen_name("swift_stdlib_connectNSBaseClasses")
+internal func _connectNSBaseClasses() -> Bool
+
+
+private let _bridgeInitializedSuccessfully = _connectNSBaseClasses()
+internal var _orphanedFoundationSubclassesReparented: Bool = false
+
+/// Reparents the SwiftNativeNS*Base classes to be subclasses of their respective
+/// Foundation types, or is false if they couldn't be reparented. Must be run
+/// in order to bridge Swift Strings, Arrays, Dictionarys, Sets, or Enumerators to ObjC.
+ internal func _connectOrphanedFoundationSubclassesIfNeeded() -> Void {
+  let bridgeWorks = _bridgeInitializedSuccessfully
+  _debugPrecondition(bridgeWorks)
+  _orphanedFoundationSubclassesReparented = true
+}
+
 //===--- Bridging for metatypes -------------------------------------------===//
 
 /// A stand-in for a value of metatype type.

stdlib/public/core/CMakeLists.txt

@@ -229,8 +229,6 @@ set(swift_core_private_link_libraries)
 set(swift_stdlib_compile_flags "${SWIFT_RUNTIME_SWIFT_COMPILE_FLAGS}")
 if(SWIFT_PRIMARY_VARIANT_SDK IN_LIST SWIFT_APPLE_PLATFORMS)
   list(APPEND swift_core_link_flags "-all_load")
-  list(APPEND swift_core_framework_depends Foundation)
-  list(APPEND swift_core_framework_depends CoreFoundation)
   list(APPEND swift_core_private_link_libraries icucore)
 else()
   # With the GNU linker the equivalent of -all_load is to tell the linker

stdlib/public/core/ContiguousArrayBuffer.swift

@@ -417,13 +417,27 @@ internal struct _ContiguousArrayBuffer<Element>: _ArrayBufferProtocol {
   }
 
 #if _runtime(_ObjC)
+  
   /// Convert to an NSArray.
   ///
   /// - Precondition: `Element` is bridged to Objective-C.
   ///
   /// - Complexity: O(1).
-  @inlinable
+  @usableFromInline
   internal __consuming func _asCocoaArray() -> AnyObject {
+    // _asCocoaArray was @inlinable in Swift 5.0 and 5.1, which means that there
+    // are existing apps out there that effectively have the old implementation
+    // Be careful with future changes to this function. Here be dragons!
+    // The old implementation was
+    // if count == 0 {
+    //   return _emptyArrayStorage
+    // }
+    // if _isBridgedVerbatimToObjectiveC(Element.self) {
+    //   return _storage
+    // }
+    // return __SwiftDeferredNSArray(_nativeStorage: _storage)
+    
+    _connectOrphanedFoundationSubclassesIfNeeded()
     if count == 0 {
       return _emptyArrayStorage
     }

stdlib/public/core/DictionaryBridging.swift

@@ -29,6 +29,7 @@ internal func _stdlib_NSDictionary_allKeys(
 extension _NativeDictionary { // Bridging
   @usableFromInline
   __consuming internal func bridged() -> AnyObject {
+    _connectOrphanedFoundationSubclassesIfNeeded()
     // We can zero-cost bridge if our keys are verbatim
     // or if we're the empty singleton.
 
@@ -67,6 +68,7 @@ final internal class _SwiftDictionaryNSEnumerator<Key: Hashable, Value>
 
   internal init(_ base: __owned _NativeDictionary<Key, Value>) {
     _internalInvariant(_isBridgedVerbatimToObjectiveC(Key.self))
+    _internalInvariant(_orphanedFoundationSubclassesReparented)
     self.base = base
     self.bridgedKeys = nil
     self.nextBucket = base.hashTable.startBucket
@@ -77,6 +79,7 @@ final internal class _SwiftDictionaryNSEnumerator<Key: Hashable, Value>
   @nonobjc
   internal init(_ deferred: __owned _SwiftDeferredNSDictionary<Key, Value>) {
     _internalInvariant(!_isBridgedVerbatimToObjectiveC(Key.self))
+    _internalInvariant(_orphanedFoundationSubclassesReparented)
     self.base = deferred.native
     self.bridgedKeys = deferred.bridgeKeys()
     self.nextBucket = base.hashTable.startBucket

stdlib/public/core/Hashing.swift

@@ -76,7 +76,10 @@ internal struct _UnmanagedAnyObjectArray {
 // renamed. The old name must not be used in the new runtime.
 final internal class __SwiftEmptyNSEnumerator
   : __SwiftNativeNSEnumerator, _NSEnumerator {
-  internal override required init() { super.init() }
+  internal override required init() {
+    super.init()
+    _internalInvariant(_orphanedFoundationSubclassesReparented)
+  }
 
   @objc
   internal func nextObject() -> AnyObject? {

stdlib/public/core/ReflectionMirror.swift

@@ -47,10 +47,12 @@ internal func getChild<T>(of value: T, type: Any.Type, index: Int) -> (label: St
 internal func _getQuickLookObject<T>(_: T) -> AnyObject?
 
 @_silgen_name("_swift_stdlib_NSObject_isKindOfClass")
-internal func _isImpl(_ object: AnyObject, kindOf: AnyObject) -> Bool
+internal func _isImpl(_ object: AnyObject, kindOf: UnsafePointer<CChar>) -> Bool
 
 internal func _is(_ object: AnyObject, kindOf `class`: String) -> Bool {
-  return _isImpl(object, kindOf: `class` as AnyObject)
+  return `class`.withCString {
+    return _isImpl(object, kindOf: $0)
+  }
 }
 
 internal func _getClassPlaygroundQuickLook(

stdlib/public/core/SetBridging.swift

@@ -14,24 +14,21 @@
 
 import SwiftShims
 
-@_silgen_name("swift_stdlib_CFSetGetValues")
-internal
-func _stdlib_CFSetGetValues(
-  _ nss: AnyObject,
-  _: UnsafeMutablePointer<AnyObject>)
-
 /// Equivalent to `NSSet.allObjects`, but does not leave objects on the
 /// autorelease pool.
 internal func _stdlib_NSSet_allObjects(_ object: AnyObject) -> _BridgingBuffer {
   let nss = unsafeBitCast(object, to: _NSSet.self)
-  let storage = _BridgingBuffer(nss.count)
-  _stdlib_CFSetGetValues(nss, storage.baseAddress)
+  let count = nss.count
+  let storage = _BridgingBuffer(count)
+  nss.getObjects(storage.baseAddress, count: count)
   return storage
 }
 
 extension _NativeSet { // Bridging
   @usableFromInline
   internal __consuming func bridged() -> AnyObject {
+    _connectOrphanedFoundationSubclassesIfNeeded()
+    
     // We can zero-cost bridge if our keys are verbatim
     // or if we're the empty singleton.
 
@@ -70,6 +67,7 @@ final internal class _SwiftSetNSEnumerator<Element: Hashable>
 
   internal init(_ base: __owned _NativeSet<Element>) {
     _internalInvariant(_isBridgedVerbatimToObjectiveC(Element.self))
+    _internalInvariant(_orphanedFoundationSubclassesReparented)
     self.base = base
     self.bridgedElements = nil
     self.nextBucket = base.hashTable.startBucket
@@ -80,6 +78,7 @@ final internal class _SwiftSetNSEnumerator<Element: Hashable>
   @nonobjc
   internal init(_ deferred: __owned _SwiftDeferredNSSet<Element>) {
     _internalInvariant(!_isBridgedVerbatimToObjectiveC(Element.self))
+    _internalInvariant(_orphanedFoundationSubclassesReparented)
     self.base = deferred.native
     self.bridgedElements = deferred.bridgeElements()
     self.nextBucket = base.hashTable.startBucket

stdlib/public/core/ShadowProtocols.swift

@@ -171,6 +171,10 @@ internal protocol _NSSetCore: _NSCopying, _NSFastEnumeration {
 /// supplies.
 @unsafe_no_objc_tagged_pointer @objc
 internal protocol _NSSet: _NSSetCore {
+  @objc(getObjects:count:) func getObjects(
+    _ buffer: UnsafeMutablePointer<AnyObject>,
+    count: Int
+  )
 }
 
 /// A shadow for the API of NSNumber we will use in the core

stdlib/public/core/StringBridge.swift

@@ -442,6 +442,9 @@ extension String {
   @_effects(releasenone)
   public // SPI(Foundation)
   func _bridgeToObjectiveCImpl() -> AnyObject {
+    
+    _connectOrphanedFoundationSubclassesIfNeeded()
+    
     // Smol ASCII a) may bridge to tagged pointers, b) can't contain a BOM
     if _guts.isSmallASCII {
       let maybeTagged = _guts.asSmall.withUTF8 { bufPtr in
@@ -453,6 +456,7 @@ extension String {
       }
       if let tagged = maybeTagged { return tagged }
     }
+    
     if _guts.isSmall {
         // We can't form a tagged pointer String, so grow to a non-small String,
         // and bridge that instead. Also avoids CF deleting any BOM that may be
@@ -497,6 +501,17 @@ public func _getDescription<T>(_ x: T) -> AnyObject {
   return String(reflecting: x)._bridgeToObjectiveCImpl()
 }
 
+@_silgen_name("swift_stdlib_NSStringFromUTF8")
+@usableFromInline //this makes the symbol available to the runtime :(
+@available(macOS 9999, iOS 9999, tvOS 9999, watchOS 9999, *)
+internal func _NSStringFromUTF8(_ s: UnsafePointer<UInt8>, _ len: Int)
+  -> AnyObject {
+  return String(
+    decoding: UnsafeBufferPointer(start: s, count: len),
+    as: UTF8.self
+  )._bridgeToObjectiveCImpl()
+}
+
 #else // !_runtime(_ObjC)
 
 internal class __SwiftNativeNSString {

stdlib/public/runtime/ErrorObject.mm

@@ -42,14 +42,28 @@
 using namespace swift;
 using namespace swift::hashable_support;
 
+// Mimic the memory layout of NSError so things don't go haywire when we
+// switch superclasses to the real thing.
+@interface __SwiftNSErrorLayoutStandin : NSObject {
+  @private
+  void *_reserved;
+  NSInteger _code;
+  id _domain;
+  id _userInfo;
+}
+@end
+
+@implementation __SwiftNSErrorLayoutStandin
+@end
+
 /// A subclass of NSError used to represent bridged native Swift errors.
 /// This type cannot be subclassed, and should not ever be instantiated
 /// except by the Swift runtime.
 ///
 /// NOTE: older runtimes called this _SwiftNativeNSError. The two must
 /// coexist, so it was renamed. The old name must not be used in the new
 /// runtime.
-@interface __SwiftNativeNSError : NSError
+@interface __SwiftNativeNSError : __SwiftNSErrorLayoutStandin
 @end
 
 @implementation __SwiftNativeNSError
@@ -71,29 +85,29 @@ - (void)dealloc {
 // layout. This gives us a buffer in case NSError decides to change its stored
 // property order.
 
-- (NSString*)domain {
+- (id /* NSString */)domain {
   auto error = (const SwiftError*)self;
   // The domain string should not be nil; if it is, then this error box hasn't
   // been initialized yet as an NSError.
   auto domain = error->domain.load(SWIFT_MEMORY_ORDER_CONSUME);
   assert(domain
          && "Error box used as NSError before initialization");
   // Don't need to .retain.autorelease since it's immutable.
-  return cf_const_cast<NSString*>(domain);
+  return cf_const_cast<id>(domain);
 }
 
 - (NSInteger)code {
   auto error = (const SwiftError*)self;
   return error->code.load(SWIFT_MEMORY_ORDER_CONSUME);
 }
 
-- (NSDictionary*)userInfo {
+- (id /* NSDictionary */)userInfo {
   auto error = (const SwiftError*)self;
   auto userInfo = error->userInfo.load(SWIFT_MEMORY_ORDER_CONSUME);
   assert(userInfo
          && "Error box used as NSError before initialization");
   // Don't need to .retain.autorelease since it's immutable.
-  return cf_const_cast<NSDictionary*>(userInfo);
+  return cf_const_cast<id>(userInfo);
 }
 
 - (id)copyWithZone:(NSZone *)zone {
@@ -153,16 +167,29 @@ - (BOOL)isEqual:(id)other {
 @end
 
 Class swift::getNSErrorClass() {
-  return SWIFT_LAZY_CONSTANT([NSError class]);
+  return SWIFT_LAZY_CONSTANT(objc_lookUpClass("NSError"));
 }
 
 const Metadata *swift::getNSErrorMetadata() {
   return SWIFT_LAZY_CONSTANT(
     swift_getObjCClassMetadata((const ClassMetadata *)getNSErrorClass()));
 }
 
+static Class getAndBridgeSwiftNativeNSErrorClass() {
+  Class nsErrorClass = swift::getNSErrorClass();
+  Class ourClass = [__SwiftNativeNSError class];
+  // We want "err as AnyObject" to do *something* even without Foundation
+  if (nsErrorClass) {
+    #pragma clang diagnostic push
+    #pragma clang diagnostic ignored "-Wdeprecated-declarations"
+      class_setSuperclass(ourClass, nsErrorClass);
+    #pragma clang diagnostic pop
+  }
+  return ourClass;
+}
+
 static Class getSwiftNativeNSErrorClass() {
-  return SWIFT_LAZY_CONSTANT([__SwiftNativeNSError class]);
+  return SWIFT_LAZY_CONSTANT(getAndBridgeSwiftNativeNSErrorClass());
 }
 
 /// Allocate a catchable error object.
@@ -274,7 +301,7 @@ static ErrorBridgingInfo getErrorBridgingInfo() {
 
 const Metadata *SwiftError::getType() const {
   if (isPureNSError()) {
-    auto asError = reinterpret_cast<NSError *>(const_cast<SwiftError *>(this));
+    id asError = reinterpret_cast<id>(const_cast<SwiftError *>(this));
     return swift_getObjCClassMetadata((ClassMetadata*)[asError class]);
   }
   return type;
@@ -363,9 +390,9 @@ static ErrorBridgingInfo getErrorBridgingInfo() {
 #define getErrorDomainNSString \
   MANGLE_SYM(s23_getErrorDomainNSStringyyXlSPyxGs0B0RzlF)
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
-NSString *getErrorDomainNSString(const OpaqueValue *error,
-                                 const Metadata *T,
-                                 const WitnessTable *Error);
+id getErrorDomainNSString(const OpaqueValue *error,
+                          const Metadata *T,
+                          const WitnessTable *Error);
 
 // internal func _getErrorCode<T : Error>(_ x: UnsafePointer<T>) -> Int
 #define getErrorCode \
@@ -379,17 +406,17 @@ NSInteger getErrorCode(const OpaqueValue *error,
 #define getErrorUserInfoNSDictionary \
   MANGLE_SYM(s29_getErrorUserInfoNSDictionaryyyXlSgSPyxGs0B0RzlF)
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
-NSDictionary *getErrorUserInfoNSDictionary(
+id getErrorUserInfoNSDictionary(
                 const OpaqueValue *error,
                 const Metadata *T,
                 const WitnessTable *Error);
 
 // @_silgen_name("_swift_stdlib_getErrorDefaultUserInfo")
 // internal func _getErrorDefaultUserInfo<T : Error>(_ x: T) -> AnyObject
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
-NSDictionary *_swift_stdlib_getErrorDefaultUserInfo(OpaqueValue *error,
-                                                    const Metadata *T,
-                                                    const WitnessTable *Error) {
+id _swift_stdlib_getErrorDefaultUserInfo(OpaqueValue *error,
+                                         const Metadata *T,
+                                         const WitnessTable *Error) {
   // public func Foundation._getErrorDefaultUserInfo<T: Error>(_ error: T)
   //   -> AnyObject?
   auto foundationGetDefaultUserInfo = getErrorBridgingInfo().GetErrorDefaultUserInfo;
@@ -407,7 +434,7 @@ NSInteger getErrorCode(const OpaqueValue *error,
 /// at +1.
 id
 swift::_swift_stdlib_bridgeErrorToNSError(SwiftError *errorObject) {
-  auto ns = reinterpret_cast<NSError *>(errorObject);
+  id ns = reinterpret_cast<id>(errorObject);
 
   // If we already have a domain set, then we've already initialized.
   // If this is a real NSError, then Cocoa and Core Foundation's initializers
@@ -431,9 +458,9 @@ NSInteger getErrorCode(const OpaqueValue *error,
   auto type = errorObject->getType();
   auto witness = errorObject->getErrorConformance();
 
-  NSString *domain = getErrorDomainNSString(value, type, witness);
+  id domain = getErrorDomainNSString(value, type, witness);
   NSInteger code = getErrorCode(value, type, witness);
-  NSDictionary *userInfo = getErrorUserInfoNSDictionary(value, type, witness);
+  id userInfo = getErrorUserInfoNSDictionary(value, type, witness);
 
   // Never produce an empty userInfo dictionary.
   if (!userInfo)
@@ -480,7 +507,7 @@ NSInteger getErrorCode(const OpaqueValue *error,
   if (![reinterpret_cast<id>(object) isKindOfClass: NSErrorClass])
     return false;
 
-  NSError *srcInstance = reinterpret_cast<NSError *>(object);
+  id srcInstance = reinterpret_cast<id>(object);
 
   // A __SwiftNativeNSError box can always be unwrapped to cast the value back
   // out as an Error existential.
@@ -523,7 +550,7 @@ ProtocolDescriptorRef theErrorProtocol(&PROTOCOL_DESCR_SYM(s5Error),
   auto *destTypeExistential = dyn_cast<ExistentialTypeMetadata>(destType);
   if (destTypeExistential &&
       destTypeExistential->getRepresentation() == ExistentialTypeRepresentation::Error) {
-    auto destBoxAddr = reinterpret_cast<NSError**>(dest);
+    auto destBoxAddr = reinterpret_cast<id*>(dest);
     *destBoxAddr = objc_retain(srcInstance);
     return true;
   }