WIP [ffigen] Avoid objc_getClass and objc_getProtocol

.github/workflows/ffigen.yml

@@ -41,6 +41,7 @@ jobs:
       - name: Check formatting
         run: dart format --output=none --set-exit-if-changed .
         if: always() && steps.install.outcome == 'success'
+      - run: git diff
       - name: Build test dylib and bindings
         run: dart --enable-asserts test/setup.dart
       - name: Analyze code

pkgs/ffigen/example/objective_c/avf_audio_bindings.dart

@@ -729,7 +729,16 @@ extension type CASpatialAudioExperience._(objc.ObjCObject object$)
   }) : object$ = objc.ObjCObject(other, retain: retain, release: release) {}
 }
 
-late final _class_AVAudioPlayer = objc.getClass("AVAudioPlayer");
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_AVAudioPlayer',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_AVAudioPlayer_raw;
+final _class_AVAudioPlayer = objc.getClass(
+  "AVAudioPlayer",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_AVAudioPlayer_raw,
+  ).cast(),
+);
 final _objc_msgSend_151sglz = objc.msgSendPointer
     .cast<
       ffi.NativeFunction<

pkgs/ffigen/example/swift/swift_api_bindings.dart

@@ -94,7 +94,16 @@ extension SwiftClass$Methods on SwiftClass {
   }
 }
 
-late final _class_SwiftClass = objc.getClass("swift_module.SwiftClass");
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_swift_module.SwiftClass',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_SwiftClass_raw;
+final _class_SwiftClass = objc.getClass(
+  "swift_module.SwiftClass",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_SwiftClass_raw,
+  ).cast(),
+);
 final _objc_msgSend_151sglz = objc.msgSendPointer
     .cast<
       ffi.NativeFunction<

pkgs/ffigen/lib/src/code_generator/objc_built_in_functions.dart

@@ -276,7 +276,7 @@ class ObjCImport {
   String gen(Context context) => '${context.libs.prefix(objcPkgImport)}.$name';
 }
 
-/// Globals only used internally by ObjC bindings, such as classes and SELs.
+/// Globals only used internally by ObjC bindings, such as selectors.
 class ObjCInternalGlobal extends NoLookUpBinding {
   final String Function() makeValue;
 
@@ -294,6 +294,83 @@ class ObjCInternalGlobal extends NoLookUpBinding {
   }
 }
 
+/// A global variable for an ObjC class, loaded via @Native.
+class ObjCClassGlobal extends NoLookUpBinding {
+  final String lookupName;
+  final Symbol rawSymbol;
+  ObjCClassGlobal(String name, this.lookupName)
+    : rawSymbol = Symbol('${name}_raw', SymbolKind.field),
+      super(
+        originalName: name,
+        symbol: Symbol(name, SymbolKind.field),
+        isInternal: true,
+      );
+
+  @override
+  BindingString toBindingString(Writer w) {
+    final context = w.context;
+    final ffi = context.libs.prefix(ffiImport);
+    final type = PointerType(objCObjectType).getCType(context);
+    final symbol = Namer.stringLiteral('OBJC_CLASS_\$_$lookupName');
+    final getClass = ObjCBuiltInFunctions.getClass.gen(context);
+    final address = '$ffi.Native.addressOf<$type>(${rawSymbol.name})';
+    final s =
+        '''
+@$ffi.Native<$type>(symbol: '$symbol')
+external $type ${rawSymbol.name};
+final $name = $getClass("$lookupName", () => $address.cast());
+''';
+    return BindingString(type: BindingStringType.global, string: s);
+  }
+
+  @override
+  void visitChildren(Visitor visitor) {
+    super.visitChildren(visitor);
+    visitor.visit(ffiImport);
+    visitor.visit(objcPkgImport);
+    visitor.visit(objCObjectType);
+    visitor.visit(rawSymbol);
+  }
+}
+
+/// A global variable for an ObjC protocol, loaded via @Native.
+class ObjCProtocolGlobal extends NoLookUpBinding {
+  final String loaderName;
+  final String lookupName;
+  final Symbol rawSymbol;
+  ObjCProtocolGlobal(String name, this.lookupName, this.loaderName)
+    : rawSymbol = Symbol('${name}_raw', SymbolKind.field),
+      super(
+        originalName: name,
+        symbol: Symbol(name, SymbolKind.field),
+        isInternal: true,
+      );
+
+  @override
+  BindingString toBindingString(Writer w) {
+    final context = w.context;
+    final ffi = context.libs.prefix(ffiImport);
+    final ptrType = PointerType(objCProtocolType).getCType(context);
+    final getProtocol = ObjCBuiltInFunctions.getProtocol.gen(context);
+    final s =
+        '''
+@$ffi.Native<$ptrType Function()>(symbol: '$loaderName')
+external $ptrType ${rawSymbol.name}();
+final $name = $getProtocol("$lookupName", ${rawSymbol.name});
+''';
+    return BindingString(type: BindingStringType.global, string: s);
+  }
+
+  @override
+  void visitChildren(Visitor visitor) {
+    super.visitChildren(visitor);
+    visitor.visit(ffiImport);
+    visitor.visit(objcPkgImport);
+    visitor.visit(objCProtocolType);
+    visitor.visit(rawSymbol);
+  }
+}
+
 enum ObjCMsgSendVariant {
   normal(ObjCBuiltInFunctions.msgSendPointer),
   stret(ObjCBuiltInFunctions.msgSendStretPointer),

pkgs/ffigen/lib/src/code_generator/objc_category.dart

@@ -15,7 +15,7 @@ class ObjCCategory extends NoLookUpBinding with ObjCMethods, HasLocalScope {
   @override
   final Context context;
   final ObjCInterface parent;
-  final ObjCInternalGlobal classObject;
+  final NoLookUpBinding classObject;
 
   final protocols = <ObjCProtocol>[];
 

pkgs/ffigen/lib/src/code_generator/objc_interface.dart

@@ -18,7 +18,7 @@ class ObjCInterface extends BindingType with ObjCMethods, HasLocalScope {
   bool filled = false;
 
   final String lookupName;
-  late final ObjCInternalGlobal classObject;
+  late final NoLookUpBinding classObject;
   late final ObjCInternalGlobal _isKindOfClass;
   late final ObjCMsgSendFunc _isKindOfClassMsgSend;
   final protocols = <ObjCProtocol>[];
@@ -46,10 +46,7 @@ class ObjCInterface extends BindingType with ObjCMethods, HasLocalScope {
              name ??
              originalName,
        ) {
-    classObject = ObjCInternalGlobal(
-      '_class_$originalName',
-      () => '${ObjCBuiltInFunctions.getClass.gen(context)}("$lookupName")',
-    );
+    classObject = ObjCClassGlobal('_class_$originalName', this.lookupName);
     _isKindOfClass = context.objCBuiltInFunctions.getSelObject(
       'isKindOfClass:',
     );

pkgs/ffigen/lib/src/code_generator/objc_protocol.dart

@@ -16,7 +16,7 @@ class ObjCProtocol extends BindingType with ObjCMethods, HasLocalScope {
   final Context context;
   final superProtocols = <ObjCProtocol>[];
   final String lookupName;
-  final ObjCInternalGlobal _protocolPointer;
+  final NoLookUpBinding _protocolPointer;
   late final ObjCInternalGlobal _conformsTo;
   late final ObjCMsgSendFunc _conformsToMsgSend;
   final ApiAvailability apiAvailability;
@@ -33,10 +33,10 @@ class ObjCProtocol extends BindingType with ObjCMethods, HasLocalScope {
     required this.apiAvailability,
     required this.context,
   }) : lookupName = lookupName ?? originalName,
-       _protocolPointer = ObjCInternalGlobal(
+       _protocolPointer = ObjCProtocolGlobal(
          '_protocol_$originalName',
-         () =>
-             '${ObjCBuiltInFunctions.getProtocol.gen(context)}("$lookupName")',
+         lookupName ?? originalName,
+         '_${context.objCBuiltInFunctions.libraryId}_$originalName',
        ),
        super(
          name:
@@ -337,6 +337,7 @@ ${generateInstanceMethodBindings(w, this)}
     final mainString =
         '''
 
+__attribute__((visibility("default"))) __attribute__((used))
 Protocol* _${libraryId}_$originalName(void) { return @protocol($originalName); }
 ''';
 

pkgs/ffigen/test/example_tests/swift_example_test.dart

@@ -59,15 +59,7 @@ void main() {
           expect(actual, contains('set someField(int value) {'));
 
           // Verify that SwiftClass is loaded using the swift_module prefix.
-          expect(
-            actual,
-            contains(
-              RegExp(
-                r'late final _class_SwiftClass.* = '
-                r'objc.getClass.*\("swift_module\.SwiftClass"\)',
-              ),
-            ),
-          );
+          expect(actual, contains(r'OBJC_CLASS_\$_swift_module.SwiftClass'));
 
           return true;
         },

pkgs/ffigen/test/native_objc_test/arc_test_bindings.dart

@@ -364,8 +364,26 @@ extension ArcTestObject$Methods on ArcTestObject {
   }
 }
 
-late final _class_ArcDtorTestObject = objc.getClass("ArcDtorTestObject");
-late final _class_ArcTestObject = objc.getClass("ArcTestObject");
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_ArcDtorTestObject',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_ArcDtorTestObject_raw;
+final _class_ArcDtorTestObject = objc.getClass(
+  "ArcDtorTestObject",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_ArcDtorTestObject_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_ArcTestObject',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_ArcTestObject_raw;
+final _class_ArcTestObject = objc.getClass(
+  "ArcTestObject",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_ArcTestObject_raw,
+  ).cast(),
+);
 final _objc_msgSend_129vhbw = objc.msgSendPointer
     .cast<
       ffi.NativeFunction<

pkgs/ffigen/test/native_objc_test/bad_method_test_bindings.dart

@@ -112,7 +112,16 @@ final class BitField extends ffi.Opaque {}
 
 final class IncompleteStruct extends ffi.Opaque {}
 
-late final _class_BadMethodTestObject = objc.getClass("BadMethodTestObject");
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_BadMethodTestObject',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_BadMethodTestObject_raw;
+final _class_BadMethodTestObject = objc.getClass(
+  "BadMethodTestObject",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_BadMethodTestObject_raw,
+  ).cast(),
+);
 final _objc_msgSend_151sglz = objc.msgSendPointer
     .cast<
       ffi.NativeFunction<

pkgs/ffigen/test/native_objc_test/bad_override_test_bindings.dart

@@ -879,21 +879,108 @@ extension Triangle$Methods on Triangle {
   }
 }
 
-late final _class_BadOverrideAunt = objc.getClass("BadOverrideAunt");
-late final _class_BadOverrideChild = objc.getClass("BadOverrideChild");
-late final _class_BadOverrideGrandchild = objc.getClass(
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_BadOverrideAunt',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_BadOverrideAunt_raw;
+final _class_BadOverrideAunt = objc.getClass(
+  "BadOverrideAunt",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_BadOverrideAunt_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_BadOverrideChild',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_BadOverrideChild_raw;
+final _class_BadOverrideChild = objc.getClass(
+  "BadOverrideChild",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_BadOverrideChild_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_BadOverrideGrandchild',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_BadOverrideGrandchild_raw;
+final _class_BadOverrideGrandchild = objc.getClass(
   "BadOverrideGrandchild",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_BadOverrideGrandchild_raw,
+  ).cast(),
 );
-late final _class_BadOverrideGrandparent = objc.getClass(
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_BadOverrideGrandparent',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_BadOverrideGrandparent_raw;
+final _class_BadOverrideGrandparent = objc.getClass(
   "BadOverrideGrandparent",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_BadOverrideGrandparent_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_BadOverrideParent',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_BadOverrideParent_raw;
+final _class_BadOverrideParent = objc.getClass(
+  "BadOverrideParent",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_BadOverrideParent_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_BadOverrideSibbling',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_BadOverrideSibbling_raw;
+final _class_BadOverrideSibbling = objc.getClass(
+  "BadOverrideSibbling",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_BadOverrideSibbling_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(
+  symbol: 'OBJC_CLASS_\$_BadOverrideUncle',
+)
+external ffi.Pointer<objc.ObjCObjectImpl> _class_BadOverrideUncle_raw;
+final _class_BadOverrideUncle = objc.getClass(
+  "BadOverrideUncle",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_BadOverrideUncle_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(symbol: 'OBJC_CLASS_\$_Polygon')
+external ffi.Pointer<objc.ObjCObjectImpl> _class_Polygon_raw;
+final _class_Polygon = objc.getClass(
+  "Polygon",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_Polygon_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(symbol: 'OBJC_CLASS_\$_Rectangle')
+external ffi.Pointer<objc.ObjCObjectImpl> _class_Rectangle_raw;
+final _class_Rectangle = objc.getClass(
+  "Rectangle",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_Rectangle_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(symbol: 'OBJC_CLASS_\$_Square')
+external ffi.Pointer<objc.ObjCObjectImpl> _class_Square_raw;
+final _class_Square = objc.getClass(
+  "Square",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_Square_raw,
+  ).cast(),
+);
+@ffi.Native<ffi.Pointer<objc.ObjCObjectImpl>>(symbol: 'OBJC_CLASS_\$_Triangle')
+external ffi.Pointer<objc.ObjCObjectImpl> _class_Triangle_raw;
+final _class_Triangle = objc.getClass(
+  "Triangle",
+  () => ffi.Native.addressOf<ffi.Pointer<objc.ObjCObjectImpl>>(
+    _class_Triangle_raw,
+  ).cast(),
 );
-late final _class_BadOverrideParent = objc.getClass("BadOverrideParent");
-late final _class_BadOverrideSibbling = objc.getClass("BadOverrideSibbling");
-late final _class_BadOverrideUncle = objc.getClass("BadOverrideUncle");
-late final _class_Polygon = objc.getClass("Polygon");
-late final _class_Rectangle = objc.getClass("Rectangle");
-late final _class_Square = objc.getClass("Square");
-late final _class_Triangle = objc.getClass("Triangle");
 final _objc_msgSend_151sglz = objc.msgSendPointer
     .cast<
       ffi.NativeFunction<