[CFE/web] Move static interop erasure and remove outline stubber

Deletes the outline stubber as it's not necessary on any backend.
DDC should compile the entire sources and outline dill in one step.
dart2wasm operates similarly, and so only needs the modular transformer.
dart2js moves the erasure to a global transform.

Also, this CL reverts now unnecessary plumbing that was needed for the
outline stubber.

Change-Id: Ic085c4fad5a6bdfc7d6916f7fa575c6ef9b20110
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/253000
Reviewed-by: Joshua Litt <joshualitt@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Srujan Gaddam <srujzs@google.com>

pkg/_js_interop_checks/lib/src/transformations/static_interop_class_eraser.dart

@@ -60,11 +60,7 @@ class StaticInteropClassEraser extends Transformer {
         .where((procedure) => procedure.name.text == stubName);
     if (stubs.isEmpty) {
       // We should only create the stub if we're processing the component in
-      // which the stub should exist. Any static invocation of the factory that
-      // doesn't exist in the same component as the factory should be processed
-      // after the component in which the factory exists. In modular
-      // compilation, the outline of that component should already contain the
-      // needed stub.
+      // which the stub should exist.
       if (currentComponent != null) {
         assert(factoryTarget.enclosingComponent == currentComponent);
       }
@@ -241,23 +237,3 @@ class _StaticInteropConstantReplacer extends ConstantReplacer {
   @override
   TreeNode visitTreeNode(TreeNode node) => node.accept(_eraser);
 }
-
-/// Used to create stubs for factories when computing outlines.
-///
-/// These stubs can then be used in downstream dependencies in modular
-/// compilation.
-class StaticInteropStubCreator extends RecursiveVisitor {
-  final StaticInteropClassEraser _eraser;
-  StaticInteropStubCreator(this._eraser);
-
-  @override
-  void visitLibrary(Library node) {
-    _eraser.currentComponent = node.enclosingComponent;
-    super.visitLibrary(node);
-  }
-
-  @override
-  void visitProcedure(Procedure node) {
-    _eraser.visitProcedure(node);
-  }
-}

pkg/compiler/lib/src/kernel/dart2js_target.dart

@@ -137,13 +137,6 @@ class Dart2jsTarget extends Target {
   @override
   bool get errorOnUnexactWebIntLiterals => true;
 
-  @override
-  void performOutlineTransformations(ir.Component component,
-      CoreTypes coreTypes, ReferenceFromIndex? referenceFromIndex) {
-    component.accept(StaticInteropStubCreator(
-        StaticInteropClassEraser(coreTypes, referenceFromIndex)));
-  }
-
   @override
   void performModularTransformationsOnLibraries(
       ir.Component component,
@@ -168,12 +161,14 @@ class Dart2jsTarget extends Target {
       // TODO (rileyporter): Merge js_util optimizations with other lowerings
       // in the single pass in `transformations/lowering.dart`.
       jsUtilOptimizer.visitLibrary(library);
-      staticInteropClassEraser.visitLibrary(library);
     }
     lowering.transformLibraries(libraries, coreTypes, hierarchy, options);
     logger?.call("Lowering transformations performed");
     if (canPerformGlobalTransforms) {
       transformMixins.transformLibraries(libraries);
+      for (var library in libraries) {
+        staticInteropClassEraser.visitLibrary(library);
+      }
       logger?.call("Mixin transformations performed");
     }
   }

pkg/compiler/lib/src/phase/load_kernel.dart

@@ -7,12 +7,15 @@ import 'dart:async';
 import 'package:collection/collection.dart';
 import 'package:front_end/src/fasta/kernel/utils.dart';
 import 'package:kernel/ast.dart' as ir;
+import 'package:kernel/core_types.dart' as ir;
 import 'package:kernel/binary/ast_from_binary.dart' show BinaryBuilder;
 
 import 'package:front_end/src/api_unstable/dart2js.dart' as fe;
 import 'package:kernel/kernel.dart' hide LibraryDependency, Combinator;
 import 'package:kernel/target/targets.dart' hide DiagnosticReporter;
 
+import 'package:_js_interop_checks/src/transformations/static_interop_class_eraser.dart';
+
 import '../../compiler_api.dart' as api;
 import '../commandline_options.dart';
 import '../common.dart';
@@ -130,6 +133,12 @@ class _LoadFromKernelResult {
 
 void _doGlobalTransforms(Component component) {
   transformMixins.transformLibraries(component.libraries);
+  // referenceFromIndex is only necessary in the case where a module containing
+  // a stub definition is invalidated, and then reloaded, because we need to
+  // keep existing references to that stub valid. Here, we have the whole
+  // program, and therefore do not need it.
+  StaticInteropClassEraser(ir.CoreTypes(component), null)
+      .visitComponent(component);
 }
 
 Future<_LoadFromKernelResult> _loadFromKernel(CompilerOptions options,

pkg/dart2wasm/lib/target.dart

@@ -86,20 +86,16 @@ class WasmTarget extends Target {
       ..parent = host;
   }
 
-  StaticInteropClassEraser _staticInteropClassEraser(
-          CoreTypes coreTypes, ReferenceFromIndex? referenceFromIndex) =>
-      StaticInteropClassEraser(coreTypes, referenceFromIndex,
-          libraryForJavaScriptObject: 'dart:_js_helper',
-          classNameOfJavaScriptObject: 'JSValue');
-
   void _performJSInteropTransformations(
       CoreTypes coreTypes,
       ClassHierarchy hierarchy,
       List<Library> interopDependentLibraries,
       ReferenceFromIndex? referenceFromIndex) {
     final jsUtilOptimizer = JsUtilWasmOptimizer(coreTypes, hierarchy);
-    final staticInteropClassEraser =
-        _staticInteropClassEraser(coreTypes, referenceFromIndex);
+    final staticInteropClassEraser = StaticInteropClassEraser(
+        coreTypes, referenceFromIndex,
+        libraryForJavaScriptObject: 'dart:_js_helper',
+        classNameOfJavaScriptObject: 'JSValue');
     for (Library library in interopDependentLibraries) {
       jsUtilOptimizer.visitLibrary(library);
       staticInteropClassEraser.visitLibrary(library);
@@ -117,13 +113,6 @@ class WasmTarget extends Target {
     _patchHostEndian(coreTypes);
   }
 
-  @override
-  void performOutlineTransformations(Component component, CoreTypes coreTypes,
-      ReferenceFromIndex? referenceFromIndex) {
-    component.accept(StaticInteropStubCreator(
-        _staticInteropClassEraser(coreTypes, referenceFromIndex)));
-  }
-
   @override
   void performModularTransformationsOnLibraries(
       Component component,

pkg/dev_compiler/lib/src/kernel/target.dart

@@ -152,13 +152,6 @@ class DevCompilerTarget extends Target {
   @override
   bool get enableNoSuchMethodForwarders => true;
 
-  @override
-  void performOutlineTransformations(Component component, CoreTypes coreTypes,
-      ReferenceFromIndex? referenceFromIndex) {
-    component.accept(StaticInteropStubCreator(
-        StaticInteropClassEraser(coreTypes, referenceFromIndex)));
-  }
-
   @override
   void performModularTransformationsOnLibraries(
       Component component,

pkg/front_end/lib/src/api_prototype/incremental_kernel_generator.dart

@@ -12,8 +12,6 @@ import 'package:kernel/core_types.dart' show CoreTypes;
 import 'package:kernel/kernel.dart'
     show Component, Library, Procedure, DartType, TypeParameter;
 
-import 'package:kernel/reference_from_index.dart';
-
 import '../base/processed_options.dart' show ProcessedOptions;
 
 import '../fasta/compiler_context.dart' show CompilerContext;
@@ -154,11 +152,7 @@ class IncrementalCompilerResult {
   final ClassHierarchy? classHierarchy;
   final CoreTypes? coreTypes;
   final Set<Library>? neededDillLibraries;
-  final ReferenceFromIndex? referenceFromIndex;
 
   IncrementalCompilerResult(this.component,
-      {this.classHierarchy,
-      this.coreTypes,
-      this.neededDillLibraries,
-      this.referenceFromIndex});
+      {this.classHierarchy, this.coreTypes, this.neededDillLibraries});
 }

pkg/front_end/lib/src/fasta/incremental_compiler.dart

@@ -529,8 +529,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       return new IncrementalCompilerResult(result,
           classHierarchy: currentKernelTarget.loader.hierarchy,
           coreTypes: currentKernelTarget.loader.coreTypes,
-          neededDillLibraries: neededDillLibraries,
-          referenceFromIndex: currentKernelTarget.loader.referenceFromIndex);
+          neededDillLibraries: neededDillLibraries);
     });
   }
 

pkg/front_end/lib/src/kernel_generator_impl.dart

@@ -188,10 +188,7 @@ Future<CompilerResult> _buildInternal(
     // summaries without building a full component (at this time, that's
     // the only need we have for these transformations).
     if (!buildComponent) {
-      options.target.performOutlineTransformations(
-          trimmedSummaryComponent,
-          kernelTarget.loader.coreTypes,
-          kernelTarget.loader.referenceFromIndex);
+      options.target.performOutlineTransformations(trimmedSummaryComponent);
       options.ticker.logMs("Transformed outline");
     }
     // Don't include source (but do add it above to include importUris).

pkg/frontend_server/lib/compute_kernel.dart

@@ -396,10 +396,7 @@ Future<ComputeKernelResult> computeKernel(List<String> args,
         incrementalComponent.problemsAsJson = null;
         incrementalComponent.setMainMethodAndMode(
             null, true, incrementalComponent.mode);
-        target.performOutlineTransformations(
-            incrementalComponent,
-            incrementalCompilerResult.coreTypes!,
-            incrementalCompilerResult.referenceFromIndex);
+        target.performOutlineTransformations(incrementalComponent);
         makeStable(incrementalComponent);
         return Future.value(fe.serializeComponent(incrementalComponent,
             includeSources: false, includeOffsets: false));

pkg/kernel/lib/target/targets.dart

@@ -314,8 +314,7 @@ abstract class Target {
   /// transformation is not applied when compiling full kernel programs to
   /// prevent affecting the internal invariants of the compiler and accidentally
   /// slowing down compilation.
-  void performOutlineTransformations(Component component, CoreTypes coreTypes,
-      ReferenceFromIndex? referenceFromIndex) {}
+  void performOutlineTransformations(Component component) {}
 
   /// Perform target-specific transformations on the given libraries that must
   /// run before constant evaluation.
@@ -1008,10 +1007,8 @@ class TargetWrapper extends Target {
   }
 
   @override
-  void performOutlineTransformations(Component component, CoreTypes coreTypes,
-      ReferenceFromIndex? referenceFromIndex) {
-    _target.performOutlineTransformations(
-        component, coreTypes, referenceFromIndex);
+  void performOutlineTransformations(Component component) {
+    _target.performOutlineTransformations(component);
   }
 
   @override
@@ -1076,10 +1073,8 @@ mixin SummaryMixin on Target {
   bool get excludeNonSources;
 
   @override
-  void performOutlineTransformations(Component component, CoreTypes coreTypes,
-      ReferenceFromIndex? referenceFromIndex) {
-    super.performOutlineTransformations(
-        component, coreTypes, referenceFromIndex);
+  void performOutlineTransformations(Component component) {
+    super.performOutlineTransformations(component);
     if (!excludeNonSources) return;
 
     List<Library> libraries = new List.of(component.libraries);