Add ConstantUse to WorldImpact

pkg/compiler/lib/src/universe/codegen_world_builder.dart

 // Copyright (c) 2017, 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.
 
 part of world_builder;
 
 /// World builder specific to codegen.
 ///
 /// This adds additional access to liveness of selectors and elements.
 abstract class CodegenWorldBuilder implements WorldBuilder {
@@ skipping 32 matching lines @@
 
   /// The set of all referenced static fields.
   ///
   /// Invariant: Elements are declaration elements.
   Iterable<FieldElement> get allReferencedStaticFields;
 }
 
 class CodegenWorldBuilderImpl implements CodegenWorldBuilder {
   final NativeClassData _nativeData;
   final ClosedWorld _world;
+  final JavaScriptConstantCompiler _constants;
 
   /// The set of all directly instantiated classes, that is, classes with a
   /// generative constructor that has been called directly and not only through
   /// a super-call.
   ///
   /// Invariant: Elements are declaration elements.
   // TODO(johnniwinther): [_directlyInstantiatedClasses] and
   // [_instantiatedTypes] sets should be merged.
   final Set<ClassElement> _directlyInstantiatedClasses =
       new Set<ClassElement>();
@@ skipping 46 matching lines @@
 
   /// Map containing instance methods of live classes that are not yet
   /// closurized.
   final Map<String, Set<_MemberUsage>> _instanceFunctionsByName =
       <String, Set<_MemberUsage>>{};
 
   final Set<ResolutionDartType> isChecks = new Set<ResolutionDartType>();
 
   final SelectorConstraintsStrategy selectorConstraintsStrategy;
 
-  CodegenWorldBuilderImpl(
-      this._nativeData, this._world, this.selectorConstraintsStrategy);
+  final Set<ConstantValue> _constantValues = new Set<ConstantValue>();
+
+  CodegenWorldBuilderImpl(this._nativeData, this._world, this._constants,
+      this.selectorConstraintsStrategy);
 
   /// Calls [f] with every instance field, together with its declarer, in an
   /// instance of [cls].
   void forEachInstanceField(
       ClassElement cls, void f(ClassEntity declarer, FieldEntity field)) {
     cls.implementation
         .forEachInstanceField(f, includeSuperAndInjectedMembers: true);
   }
 
   @override
@@ skipping 344 matching lines @@
         classUsed(usage.cls, usage.instantiate());
         return true;
       }
       return false;
     }
 
     while (cls != null && processClass(cls)) {
       cls = cls.superclass;
     }
   }
+
+  /// Register the constant [use] with this world builder. Returns `true` if
+  /// the constant use was new to the world.
+  bool registerConstantUse(ConstantUse use) {
+    if (use.kind == ConstantUseKind.DIRECT) {
+      _constants.addCompileTimeConstantForEmission(use.value);
+    }
+    return _constantValues.add(use.value);
+  }
 }