Revert "Move towards using WorldImpact for codegen"

pkg/compiler/lib/src/js_backend/lookup_map_analysis.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// Analysis to determine how to generate code for `LookupMap`s.
 library compiler.src.js_backend.lookup_map_analysis;
 
 import 'package:pub_semver/pub_semver.dart';
 
 import '../common.dart';
 import '../common/registry.dart' show Registry;
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart'
     show
         ConstantValue,
         ConstructedConstantValue,
         ListConstantValue,
         NullConstantValue,
         StringConstantValue,
         TypeConstantValue;
 import '../dart_types.dart' show DartType;
 import '../dart_types.dart' show InterfaceType;
 import '../elements/elements.dart'
     show ClassElement, FieldElement, LibraryElement, VariableElement;
-import '../enqueue.dart';
-import '../universe/world_impact.dart'
-    show WorldImpact, StagedWorldImpactBuilder;
 import 'js_backend.dart' show JavaScriptBackend;
 
 /// An analysis and optimization to remove unused entries from a `LookupMap`.
 ///
 /// `LookupMaps` are defined in `package:lookup_map/lookup_map.dart`. They are
 /// simple maps that contain constant expressions as keys, and that only support
 /// the lookup operation.
 ///
 /// This analysis and optimization will tree-shake the contents of the maps by
 /// looking at the program and finding which keys are clearly unused. Not all
@@ skipping 76 matching lines @@
   /// runtime. Technically if we limit lookup-maps to check for identical keys,
   /// we could allow const instances of these types.  However, we internally use
   /// a hash map within lookup-maps today, so we need this restriction.
   final _typesWithEquals = <ClassElement, bool>{};
 
   /// Pending work to do if we discover that a new key is in use. For each key
   /// that we haven't seen, we record the list of lookup-maps that contain an
   /// entry with that key.
   final _pending = <ConstantValue, List<_LookupMapInfo>>{};
 
-  final StagedWorldImpactBuilder impactBuilder = new StagedWorldImpactBuilder();
-
   /// Whether the backend is currently processing the codegen queue.
   bool _inCodegen = false;
 
   LookupMapAnalysis(this.backend, this.reporter);
 
-  void onQueueEmpty(Enqueuer enqueuer) {
-    if (enqueuer.isResolutionQueue) return;
-    enqueuer.applyImpact(null, impactBuilder.flush());
-  }
-
   /// Whether this analysis and optimization is enabled.
   bool get _isEnabled {
     // `lookupMap==off` kept here to make it easy to test disabling this feature
     if (const String.fromEnvironment('lookupMap') == 'off') return false;
     return typeLookupMapClass != null;
   }
 
   /// Initializes this analysis by providing the resolved library. This is
   /// invoked during resolution when the `lookup_map` library is discovered.
   void init(LibraryElement library) {
@@ skipping 105 matching lines @@
   }
 
   /// Callback from the enqueuer, invoked when [element] is instantiated.
   void registerInstantiatedClass(ClassElement element) {
     if (!_isEnabled || !_inCodegen) return;
     // TODO(sigmund): only add if .runtimeType is ever used
     _addClassUse(element);
   }
 
   /// Callback from the enqueuer, invoked when [type] is instantiated.
-  void registerInstantiatedType(InterfaceType type) {
+  void registerInstantiatedType(InterfaceType type, Registry registry) {
     if (!_isEnabled || !_inCodegen) return;
     // TODO(sigmund): only add if .runtimeType is ever used
     _addClassUse(type.element);
     // TODO(sigmund): only do this when type-argument expressions are used?
-    _addGenerics(type);
+    _addGenerics(type, registry);
   }
 
   /// Records generic type arguments in [type], in case they are retrieved and
   /// returned using a type-argument expression.
-  void _addGenerics(InterfaceType type) {
+  void _addGenerics(InterfaceType type, Registry registry) {
     if (!type.isGeneric) return;
     for (var arg in type.typeArguments) {
       if (arg is InterfaceType) {
         _addClassUse(arg.element);
         // Note: this call was needed to generate correct code for
         // type_lookup_map/generic_type_test
         // TODO(sigmund): can we get rid of this?
-        backend.computeImpactForInstantiatedConstantType(
-            backend.typeImplementation.rawType, impactBuilder);
-        _addGenerics(arg);
+        backend.registerInstantiatedConstantType(
+            backend.typeImplementation.rawType, registry);
+        _addGenerics(arg, registry);
       }
     }
   }
 
   /// Callback from the codegen enqueuer, invoked when a constant (which is
   /// possibly a const key or a type literal) is used in the program.
   void registerTypeConstant(ClassElement element) {
     if (!_isEnabled || !_inCodegen) return;
     _addClassUse(element);
   }
@@ skipping 118 matching lines @@
   }
 
   /// Marks that [key] has been seen, and thus, the corresponding entry in this
   /// map should be considered reachable.
   _markUsed(ConstantValue key) {
     assert(!emitted);
     assert(unusedEntries.containsKey(key));
     assert(!usedEntries.containsKey(key));
     ConstantValue constant = unusedEntries.remove(key);
     usedEntries[key] = constant;
-    analysis.backend.computeImpactForCompileTimeConstant(
-        constant, analysis.impactBuilder, false);
+    analysis.backend.registerCompileTimeConstant(
+        constant, analysis.backend.compiler.globalDependencies);
   }
 
   /// Restores [original] to contain all of the entries marked as possibly used.
   void _prepareForEmission() {
     ListConstantValue originalEntries = original.fields[analysis.entriesField];
     DartType listType = originalEntries.type;
     List<ConstantValue> keyValuePairs = <ConstantValue>[];
     usedEntries.forEach((key, value) {
       keyValuePairs.add(key);
       keyValuePairs.add(value);
     });
 
     // Note: we are restoring the entries here, see comment in [original].
     if (singlePair) {
       assert(keyValuePairs.length == 0 || keyValuePairs.length == 2);
       if (keyValuePairs.length == 2) {
         original.fields[analysis.keyField] = keyValuePairs[0];
         original.fields[analysis.valueField] = keyValuePairs[1];
       }
     } else {
       original.fields[analysis.entriesField] =
           new ListConstantValue(listType, keyValuePairs);
     }
   }
 }
 
 final _validLookupMapVersionConstraint = new VersionConstraint.parse('^0.0.1');