[dart2wasm] Add support for overrideable function dispatch to handle signature changing param count.

We compare the signatures from the main module and the dynamic module. If the dynamic module has more parameters these must be from an override with extra optional paramters so we can provide the default value.

Change-Id: I818187fde3e38812dcdae0a14bbeefec4ee91e51
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/416460
Reviewed-by: Martin Kustermann <[email protected]>
Commit-Queue: Nate Biggs <[email protected]>

Author: natebiggs

pkg/dart2wasm/lib/dynamic_modules.dart

@@ -572,9 +572,10 @@ class DynamicModuleInfo {
       final mainSelector = translator.dynamicMainModuleDispatchTable!
           .selectorForTarget(reference);
       signature = _getGeneralizedSignature(mainSelector);
-      buildMain = buildSelectorBranch(reference, useUncheckedEntry, signature);
+      buildMain =
+          buildSelectorBranch(reference, useUncheckedEntry, mainSelector);
       buildDynamic =
-          buildSelectorBranch(reference, useUncheckedEntry, signature);
+          buildSelectorBranch(reference, useUncheckedEntry, mainSelector);
 
       _createUpdateableFunction(
           mainSelector.id + BuiltinUpdatableFunctions.values.length,
@@ -690,8 +691,6 @@ class DynamicModuleInfo {
 
     // The shared entry point to this selector has to use 'any' because the
     // selector's signature may change between compilations.
-    // TODO(natebiggs): This doesn't account for overrides with extra
-    // parameters.
     final generalizedSignature = translator.typesBuilder.defineFunction([
       ...signature.inputs.map((e) => const w.RefType.any(nullable: true)),
       w.NumType.i32
@@ -701,26 +700,86 @@ class DynamicModuleInfo {
     return generalizedSignature;
   }
 
-  void Function(w.FunctionBuilder) buildSelectorBranch(Reference target,
-      bool useUncheckedEntry, w.FunctionType generalizedSignature) {
+  void Function(w.FunctionBuilder) buildSelectorBranch(
+      Reference target, bool useUncheckedEntry, SelectorInfo mainSelector) {
     return (w.FunctionBuilder function) {
-      final selector = translator.dispatchTable.selectorForTarget(target);
-      final localSignature = selector.signature;
+      final localSelector = translator.dispatchTable.selectorForTarget(target);
+      final localSignature = localSelector.signature;
       final ib = function.body;
 
-      final offset = selector.targets(unchecked: useUncheckedEntry).offset;
+      final offset = localSelector.targets(unchecked: useUncheckedEntry).offset;
 
       if (offset == null) {
         ib.unreachable();
         ib.end();
         return;
       }
 
-      for (int i = 0; i < ib.locals.length - 1; i++) {
-        ib.local_get(ib.locals[i]);
-        translator.convertType(
-            ib, generalizedSignature.inputs[i], localSignature.inputs[i]);
+      final generalizedMainSignature = _getGeneralizedSignature(mainSelector);
+
+      final mainParamInfo = mainSelector.paramInfo;
+      final localParamInfo = localSelector.paramInfo;
+
+      assert(mainParamInfo.takesContextOrReceiver ==
+          localParamInfo.takesContextOrReceiver);
+
+      int localsIndex = 0;
+      final takesContextOrReceiver = localParamInfo.takesContextOrReceiver;
+      if (takesContextOrReceiver) {
+        ib.local_get(ib.locals[localsIndex]);
+        translator.convertType(ib, generalizedMainSignature.inputs[localsIndex],
+            localSignature.inputs[localsIndex]);
+        localsIndex++;
+      }
+
+      final mainTypeParamCount = mainParamInfo.typeParamCount;
+      assert(mainTypeParamCount == localParamInfo.typeParamCount);
+      for (int i = 0; i < mainTypeParamCount; i++, localsIndex++) {
+        ib.local_get(ib.locals[localsIndex]);
+        translator.convertType(ib, generalizedMainSignature.inputs[localsIndex],
+            localSignature.inputs[localsIndex]);
+      }
+
+      final localPositionalCount = localParamInfo.positional.length;
+      final mainPositionalCount = mainParamInfo.positional.length;
+      assert(localPositionalCount >= mainPositionalCount);
+
+      for (int i = 0; i < localPositionalCount; i++, localsIndex++) {
+        if (i < mainPositionalCount) {
+          ib.local_get(ib.locals[localsIndex]);
+          translator.convertType(
+              ib,
+              generalizedMainSignature.inputs[localsIndex],
+              localSignature.inputs[localsIndex]);
+          continue;
+        }
+        final constant = localParamInfo.positional[i]!;
+        translator.constants.instantiateConstant(
+            ib, constant, localSignature.inputs[localsIndex]);
+      }
+
+      final localNamedCount = localParamInfo.named.length;
+      final mainNamedCount = mainParamInfo.named.length;
+      assert(localNamedCount >= mainNamedCount);
+
+      for (int i = 0; i < localNamedCount; i++, localsIndex++) {
+        final name = localParamInfo.names[i];
+        final mainIndex = mainParamInfo.nameIndex[name];
+        if (mainIndex != null) {
+          final mainLocalIndex =
+              (takesContextOrReceiver ? 1 : 0) + mainTypeParamCount + mainIndex;
+          ib.local_get(ib.locals[mainLocalIndex]);
+          translator.convertType(
+              ib,
+              generalizedMainSignature.inputs[mainLocalIndex],
+              localSignature.inputs[localsIndex]);
+          continue;
+        }
+        final constant = localParamInfo.named[name]!;
+        translator.constants.instantiateConstant(
+            ib, constant, localSignature.inputs[localsIndex]);
       }
+
       ib.local_get(ib.locals.last);
       if (isDynamicModule) {
         translator.callReference(translator.scopeClassId.reference, ib);
@@ -732,7 +791,7 @@ class DynamicModuleInfo {
       final table = translator.dispatchTable.getWasmTable(ib.module);
       ib.call_indirect(localSignature, table);
       translator.convertType(ib, localSignature.outputs.single,
-          generalizedSignature.outputs.single);
+          generalizedMainSignature.outputs.single);
       ib.end();
     };
   }
@@ -778,9 +837,9 @@ class DynamicModuleInfo {
     _callClassIdBranch(key, useUncheckedEntry, b, generalizedSignature,
         name: '#s${mainModuleSelector.id}_${mainModuleSelector.name}',
         buildMainMatch: buildSelectorBranch(
-            interfaceTarget, useUncheckedEntry, generalizedSignature),
+            interfaceTarget, useUncheckedEntry, mainModuleSelector),
         buildDynamicMatch: buildSelectorBranch(
-            interfaceTarget, useUncheckedEntry, generalizedSignature),
+            interfaceTarget, useUncheckedEntry, mainModuleSelector),
         skipDynamic: translator.isDynamicModule &&
             selector
                 .targets(unchecked: useUncheckedEntry)

pkg/dynamic_modules/test/data/override_extra_params/dynamic_interface.yaml

@@ -9,6 +9,12 @@ can-be-overridden:
   - library: 'shared/shared.dart'
     class: 'Base'
     member: 'method1'
+  - library: 'shared/shared.dart'
+    class: 'Base'
+    member: 'method2'
+  - library: 'shared/shared.dart'
+    class: 'Base'
+    member: 'method3'
 
 # TODO(sigmund): consider implying this for all extendable types.
 callable:
@@ -27,3 +33,6 @@ callable:
     member: 'override'
   - library: 'dart:core'
     class: 'num'
+  - library: 'dart:core'
+    class: 'String'
+    member: 'get:length'

pkg/dynamic_modules/test/data/override_extra_params/main.dart

@@ -12,5 +12,7 @@ import 'shared/shared.dart' show Base;
 void main() async {
   final o = (await helper.load('entry1.dart')) as Base;
   Expect.equals(1, o.method1(1));
+  Expect.equals(5, o.method2(2, j: 3));
+  Expect.equals(5, o.method3<num>(2, j: 3));
   helper.done();
 }

pkg/dynamic_modules/test/data/override_extra_params/modules/entry1.dart

@@ -7,6 +7,12 @@ import '../shared/shared.dart';
 class Child extends Base {
   @override
   int method1(int i, [int? j]) => i + (j ?? 0);
+
+  @override
+  int method2(int i, {int? j, String? a}) => i + (j ?? 0) + (a?.length ?? 0);
+
+  @override
+  int method3<T>(int i, {int? j, T? a}) => i + (j ?? 0);
 }
 
 @pragma('dyn-module:entry-point')

pkg/dynamic_modules/test/data/override_extra_params/shared/shared.dart

@@ -4,4 +4,8 @@
 
 abstract class Base {
   int method1(int i) => i;
+
+  int method2(int i, {int? j}) => i;
+
+  int method3<T>(int i, {int? j}) => i;
 }