[cfe] Use OffsetMap for BodyBuilder.finishFields

Change-Id: I1bc39b3bbd8a78466b90856017b0af4ed1c67d2a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/401061
Commit-Queue: Johnni Winther <[email protected]>
Reviewed-by: Chloe Stefantsova <[email protected]>

Author: johnniwinther

pkg/front_end/lib/src/kernel/body_builder.dart

@@ -92,6 +92,7 @@ import '../codes/cfe_codes.dart'
 import '../codes/cfe_codes.dart' as cfe;
 import '../dill/dill_library_builder.dart' show DillLibraryBuilder;
 import '../source/diet_parser.dart';
+import '../source/offset_map.dart';
 import '../source/source_field_builder.dart';
 import '../source/source_library_builder.dart';
 import '../source/source_member_builder.dart';
@@ -965,7 +966,7 @@ class BodyBuilder extends StackListenerImpl
     assert(checkState(beginToken, [ValueKinds.Integer]));
   }
 
-  void finishFields() {
+  void finishFields(OffsetMap offsetMap) {
     debugEvent("finishFields");
     assert(checkState(null, [/*field count*/ ValueKinds.Integer]));
     int count = pop() as int;
@@ -976,27 +977,7 @@ class BodyBuilder extends StackListenerImpl
       ]));
       Expression? initializer = pop() as Expression?;
       Identifier identifier = pop() as Identifier;
-      String name = identifier.name;
-      Builder declaration = _context.lookupLocalMember(name, required: true)!;
-      int fileOffset = identifier.nameOffset;
-      while (declaration.next != null) {
-        // If we have duplicates, we try to find the right declaration.
-        if (declaration.fileUri == uri &&
-            declaration.fileOffset == fileOffset) {
-          break;
-        }
-        declaration = declaration.next!;
-      }
-      if (declaration.fileUri != uri || declaration.fileOffset != fileOffset) {
-        // If we don't have the right declaration, skip the initializer.
-        continue;
-      }
-      SourceFieldBuilder fieldBuilder;
-      if (declaration.isField) {
-        fieldBuilder = declaration as SourceFieldBuilder;
-      } else {
-        continue;
-      }
+      SourceFieldBuilder fieldBuilder = offsetMap.lookupField(identifier);
       if (initializer != null) {
         if (!fieldBuilder.hasBodyBeenBuilt) {
           initializer = typeInferrer

pkg/front_end/lib/src/kernel/body_builder_context.dart

@@ -655,6 +655,7 @@ class _TopLevelBodyBuilderDeclarationContext
       : super._(libraryBuilder);
 
   @override
+  // Coverage-ignore(suite): Not run.
   Builder? lookupLocalMember(String name, {bool required = false}) {
     return _libraryBuilder.lookupLocalMember(name, required: required);
   }

pkg/front_end/lib/src/source/diet_listener.dart

@@ -936,6 +936,7 @@ class DietListener extends StackListenerImpl {
     // TODO(paulberry): don't re-parse the field if we've already parsed it
     // for type inference.
     _parseFields(
+        _offsetMap,
         createListener(declaration.createBodyBuilderContext(), memberScope,
             inferenceDataForTesting: declaration
                 .dataForTesting
@@ -1297,8 +1298,8 @@ class DietListener extends StackListenerImpl {
     }
   }
 
-  void _parseFields(BodyBuilder bodyBuilder, Token startToken, Token? metadata,
-      bool isTopLevel) {
+  void _parseFields(OffsetMap offsetMap, BodyBuilder bodyBuilder,
+      Token startToken, Token? metadata, bool isTopLevel) {
     Token token = startToken;
     Parser parser = new Parser(bodyBuilder,
         useImplicitCreationExpression: useImplicitCreationExpressionInCfe,
@@ -1309,7 +1310,7 @@ class DietListener extends StackListenerImpl {
       // TODO(danrubel): disambiguate between class/mixin/extension members
       token = parser.parseClassMember(metadata ?? token, null).next!;
     }
-    bodyBuilder.finishFields();
+    bodyBuilder.finishFields(_offsetMap);
 
     bodyBuilder.checkEmpty(token.charOffset);
   }

pkg/front_end/test/coverage_suite_expected.dart

@@ -560,12 +560,12 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
   ),
   // 100.0%.
   "package:front_end/src/kernel/body_builder.dart": (
-    hitCount: 7196,
+    hitCount: 7180,
     missCount: 0,
   ),
   // 100.0%.
   "package:front_end/src/kernel/body_builder_context.dart": (
-    hitCount: 346,
+    hitCount: 343,
     missCount: 0,
   ),
   // 100.0%.
@@ -850,7 +850,7 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
   ),
   // 100.0%.
   "package:front_end/src/source/diet_listener.dart": (
-    hitCount: 657,
+    hitCount: 659,
     missCount: 0,
   ),
   // 100.0%.