[cfe] Add Resolver

This adds a Resolver class that encapsulates all use of the BodyBuilder. Furthermore, the external interface of BodyBuilder is extracted into the BodyBuilder interface and the BodyBuilderImpl implementation.

This is a step towards separating the BodyBuilder from the TypeInferrer. In future CLs the inferrer will be removed from BodyBuilder and Resolved will be responsible for first calling the BodyBuilder to create the uninferred AST nodes and then call the TypeInferrer to created the inferred and lowered AST nodes.


Change-Id: I198e2a65400555878d7b6c330fc6ef23be88851d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/449321
Reviewed-by: Jens Johansen <[email protected]>
Commit-Queue: Johnni Winther <[email protected]>

Author: johnniwinther

pkg/front_end/lib/src/builder/formal_parameter_builder.dart

@@ -15,13 +15,12 @@ import 'package:kernel/ast.dart'
         VariableDeclaration;
 import 'package:kernel/class_hierarchy.dart';
 
-import '../base/constant_context.dart' show ConstantContext;
 import '../base/lookup_result.dart';
 import '../base/modifiers.dart';
 import '../base/scope.dart' show LookupScope;
-import '../kernel/body_builder.dart' show BodyBuilder;
 import '../kernel/body_builder_context.dart';
 import '../kernel/internal_ast.dart' show VariableDeclarationImpl;
+import '../kernel/resolver.dart';
 import '../kernel/wildcard_lowering.dart';
 import '../source/fragment_factory.dart';
 import '../source/source_constructor_builder.dart';
@@ -296,32 +295,22 @@ class FormalParameterBuilder extends NamedBuilderImpl
           declarationBuilder,
           this,
         );
-        BodyBuilder bodyBuilder = libraryBuilder.loader
-            .createBodyBuilderForOutlineExpression(
-              libraryBuilder,
-              bodyBuilderContext,
-              scope,
-              fileUri,
-            );
-        ConstantContext constantContext = ConstantContext.required;
-        bodyBuilder.constantContext = constantContext;
         assert(!initializerWasInferred);
-        Expression initializer = bodyBuilder.parseFieldInitializer(
-          initializerToken!,
-        );
-        initializer = bodyBuilder.typeInferrer.inferParameterInitializer(
+        Resolver resolver = libraryBuilder.loader.createResolver();
+        Expression initializer = resolver.buildParameterInitializer(
+          libraryBuilder: libraryBuilder,
+          bodyBuilderContext: bodyBuilderContext,
+          scope: scope,
           fileUri: fileUri,
-          initializer: initializer,
+          initializerToken: initializerToken!,
           declaredType: variable!.type,
           hasDeclaredInitializer: hasDeclaredInitializer,
-          constantContext: constantContext,
         );
         variable!.initializer = initializer..parent = variable;
         if (initializer is InvalidExpression) {
           variable!.isErroneouslyInitialized = true;
         }
         initializerWasInferred = true;
-        bodyBuilder.performBacklogComputations();
       } else if (kind.isOptional) {
         // As done by BodyBuilder.endFormalParameter.
         variable!.initializer = new NullLiteral()..parent = variable;

pkg/front_end/lib/src/builder/metadata_builder.dart

@@ -9,14 +9,29 @@ import 'package:kernel/clone.dart';
 
 import '../base/loader.dart';
 import '../base/scope.dart' show LookupScope;
-import '../kernel/body_builder.dart' show BodyBuilder;
 import '../kernel/body_builder_context.dart';
 import '../kernel/macro/metadata.dart';
 import '../source/source_library_builder.dart' show SourceLibraryBuilder;
 
 bool computeSharedExpressionForTesting = false;
 bool delaySharedExpressionLookupForTesting = false;
 
+class Annotation {
+  final MetadataBuilder metadataBuilder;
+
+  final Token atToken;
+  final bool createFileUriExpression;
+
+  Annotation(
+    this.metadataBuilder,
+    this.atToken, {
+    required this.createFileUriExpression,
+  });
+
+  late int annotationIndex;
+  late Expression expression;
+}
+
 class MetadataBuilder {
   /// Token for `@` for annotations that have not yet been parsed.
   Token? _atToken;
@@ -56,30 +71,23 @@ class MetadataBuilder {
     required Annotatable annotatable,
     required Uri annotatableFileUri,
     required List<MetadataBuilder>? metadata,
+    required Uri annotationsFileUri,
     required BodyBuilderContext bodyBuilderContext,
     required SourceLibraryBuilder libraryBuilder,
     required LookupScope scope,
   }) {
     if (metadata == null) return;
 
-    // [BodyBuilder] used to build annotations from [Token]s.
-    BodyBuilder? bodyBuilder;
     // Cloner used to clone already parsed annotations.
     CloneVisitorNotMembers? cloner;
 
-    // Map from annotation builder of parsed annotations to the index of the
-    // corresponding annotation in `parent.annotations`.
-    //
-    // This is used to read the fully inferred annotation from [parent] and
-    // store it in `_expression` of the corresponding [MetadataBuilder].
-    Map<MetadataBuilder, int> parsedAnnotationBuilders = {};
-
-    List<int> indicesOfAnnotationsToBeInferred = [];
+    List<Annotation> annotations = [];
     for (int i = 0; i < metadata.length; ++i) {
       MetadataBuilder annotationBuilder = metadata[i];
       bool createFileUriExpression =
           annotatableFileUri != annotationBuilder.fileUri;
       Token? beginToken = annotationBuilder._atToken;
+      annotationBuilder._atToken = null;
       if (beginToken != null) {
         if (computeSharedExpressionForTesting) {
           // Coverage-ignore-block(suite): Not run.
@@ -102,29 +110,13 @@ class MetadataBuilder {
                 );
           }
         }
-
-        bodyBuilder ??= libraryBuilder.loader
-            .createBodyBuilderForOutlineExpression(
-              libraryBuilder,
-              bodyBuilderContext,
-              scope,
-              annotationBuilder.fileUri,
-            );
-        Expression annotation = bodyBuilder.parseAnnotation(beginToken);
-        annotationBuilder._atToken = null;
-        if (createFileUriExpression) {
-          annotation = new FileUriExpression(
-            annotation,
-            annotationBuilder.fileUri,
-          )..fileOffset = annotationBuilder.atOffset;
-        }
-        // Record the index of [annotation] in `parent.annotations`.
-        int annotationIndex = annotatable.annotations.length;
-        parsedAnnotationBuilders[annotationBuilder] = annotationIndex;
-        indicesOfAnnotationsToBeInferred.add(annotationIndex);
-        // It is important for the inference and backlog computations that the
-        // annotation is already a child of [parent].
-        annotatable.addAnnotation(annotation);
+        annotations.add(
+          new Annotation(
+            annotationBuilder,
+            beginToken,
+            createFileUriExpression: createFileUriExpression,
+          ),
+        );
       } else {
         // The annotation is needed for multiple declarations so we need to
         // clone the expression to use it more than once. For instance
@@ -157,19 +149,16 @@ class MetadataBuilder {
         annotatable.addAnnotation(annotation);
       }
     }
-    if (bodyBuilder != null) {
-      bodyBuilder.inferAnnotations(
-        annotatable,
-        annotatable.annotations,
-        indices: indicesOfAnnotationsToBeInferred,
-      );
-      bodyBuilder.performBacklogComputations();
-      for (MapEntry<MetadataBuilder, int> entry
-          in parsedAnnotationBuilders.entries) {
-        MetadataBuilder annotationBuilder = entry.key;
-        int index = entry.value;
-        annotationBuilder._expression = annotatable.annotations[index];
-      }
+    libraryBuilder.loader.createResolver().buildAnnotations(
+      libraryBuilder: libraryBuilder,
+      bodyBuilderContext: bodyBuilderContext,
+      annotationsFileUri: annotationsFileUri,
+      scope: scope,
+      annotatable: annotatable,
+      annotations: annotations,
+    );
+    for (Annotation annotation in annotations) {
+      annotation.metadataBuilder._expression = annotation.expression;
     }
   }
 }

pkg/front_end/lib/src/fragment/class/declaration.dart

@@ -81,6 +81,7 @@ class RegularClassDeclaration implements ClassDeclaration {
       annotatable: annotatable,
       annotatableFileUri: annotatableFileUri,
       metadata: _fragment.metadata,
+      annotationsFileUri: _fragment.fileUri,
       bodyBuilderContext: bodyBuilderContext,
       libraryBuilder: libraryBuilder,
       scope: _fragment.enclosingScope,
@@ -147,6 +148,7 @@ class EnumDeclaration implements ClassDeclaration {
       annotatable: annotatable,
       annotatableFileUri: annotatableFileUri,
       metadata: _fragment.metadata,
+      annotationsFileUri: _fragment.fileUri,
       bodyBuilderContext: bodyBuilderContext,
       libraryBuilder: libraryBuilder,
       scope: _fragment.enclosingScope,
@@ -214,6 +216,7 @@ class NamedMixinApplication implements ClassDeclaration {
       annotatable: annotatable,
       annotatableFileUri: annotatableFileUri,
       metadata: _fragment.metadata,
+      annotationsFileUri: _fragment.fileUri,
       bodyBuilderContext: bodyBuilderContext,
       libraryBuilder: libraryBuilder,
       scope: _fragment.enclosingScope,
@@ -340,6 +343,7 @@ class MixinDeclaration implements ClassDeclaration {
       annotatable: annotatable,
       annotatableFileUri: annotatableFileUri,
       metadata: _fragment.metadata,
+      annotationsFileUri: _fragment.fileUri,
       bodyBuilderContext: bodyBuilderContext,
       libraryBuilder: libraryBuilder,
       scope: _fragment.enclosingScope,

pkg/front_end/lib/src/fragment/constructor/declaration.dart

@@ -9,7 +9,6 @@ import 'package:kernel/class_hierarchy.dart';
 import 'package:kernel/type_algebra.dart';
 import 'package:kernel/type_environment.dart';
 
-import '../../base/constant_context.dart';
 import '../../base/identifiers.dart';
 import '../../base/local_scope.dart';
 import '../../base/messages.dart';
@@ -23,9 +22,9 @@ import '../../builder/metadata_builder.dart';
 import '../../builder/omitted_type_builder.dart';
 import '../../builder/type_builder.dart';
 import '../../builder/variable_builder.dart';
-import '../../kernel/body_builder.dart';
 import '../../kernel/body_builder_context.dart';
 import '../../kernel/kernel_helper.dart';
+import '../../kernel/resolver.dart';
 import '../../kernel/type_algorithms.dart';
 import '../../source/check_helper.dart';
 import '../../source/name_scheme.dart';
@@ -244,19 +243,14 @@ mixin _ConstructorDeclarationMixin
       List<Initializer>? initializers;
       Token? beginInitializers = this._beginInitializers;
       if (beginInitializers != null) {
-        BodyBuilder bodyBuilder = libraryBuilder.loader
-            .createBodyBuilderForOutlineExpression(
-              libraryBuilder,
-              createBodyBuilderContext(constructorBuilder),
-              _typeParameterScope,
-              fileUri,
-            );
-        if (isConst) {
-          bodyBuilder.constantContext = ConstantContext.required;
-        }
-        initializers = bodyBuilder.parseInitializers(
-          beginInitializers,
-          doFinishConstructor: false,
+        Resolver resolver = libraryBuilder.loader.createResolver();
+        initializers = resolver.buildInitializersUnfinished(
+          libraryBuilder: libraryBuilder,
+          bodyBuilderContext: createBodyBuilderContext(constructorBuilder),
+          typeParameterScope: _typeParameterScope,
+          fileUri: fileUri,
+          beginInitializers: beginInitializers,
+          isConst: isConst,
         );
       }
       _finalizeSuperInitializingFormals(
@@ -575,23 +569,17 @@ mixin _ConstructorDeclarationMixin
       } else {
         formalParameterScope = null;
       }
-      BodyBuilder bodyBuilder = libraryBuilder.loader
-          .createBodyBuilderForOutlineExpression(
-            libraryBuilder,
-            createBodyBuilderContext(constructorBuilder),
-            _typeParameterScope,
-            fileUri,
-            formalParameterScope: formalParameterScope,
-          );
-      if (isConst) {
-        bodyBuilder.constantContext = ConstantContext.required;
-      }
-      constructorBuilder.inferFormalTypes(bodyBuilder.hierarchy);
-      bodyBuilder.parseInitializers(
-        _beginInitializers!,
-        doFinishConstructor: isConst,
+      Resolver resolver = libraryBuilder.loader.createResolver();
+      resolver.buildInitializers(
+        libraryBuilder: libraryBuilder,
+        constructorBuilder: constructorBuilder,
+        typeParameterScope: _typeParameterScope,
+        formalParameterScope: formalParameterScope,
+        bodyBuilderContext: createBodyBuilderContext(constructorBuilder),
+        fileUri: fileUri,
+        beginInitializers: _beginInitializers!,
+        isConst: isConst,
       );
-      bodyBuilder.performBacklogComputations();
     }
   }
 
@@ -998,6 +986,7 @@ class RegularConstructorDeclaration
         annotatable: annotatable,
         annotatableFileUri: annotatablesFileUri,
         metadata: _fragment.metadata,
+        annotationsFileUri: _fragment.fileUri,
         bodyBuilderContext: bodyBuilderContext,
         libraryBuilder: libraryBuilder,
         scope: _fragment.enclosingScope,