Reapply "Fix issues with field names by ensuring that fields have exactly one name regardless of ho…

sdk/lib/_internal/compiler/implementation/js_backend/namer.dart

 // Copyright (c) 2011, 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 js_backend;
 
 /**
  * Assigns JavaScript identifiers to Dart variables, class-names and members.
  */
 class Namer implements ClosureNamer {
@@ skipping 208 matching lines @@
   final String metadataField = '@';
   final String callCatchAllName = r'call$catchAll';
   final String reflectableField = r'$reflectable';
   final String defaultValuesField = r'$defaultValues';
   final String methodsWithOptionalArgumentsField =
       r'$methodsWithOptionalArguments';
 
   // Name of property in a class description for the native dispatch metadata.
   final String nativeSpecProperty = '%';
 
+  static final RegExp IDENTIFIER = new RegExp(r'^[A-Za-z_$][A-Za-z0-9_$]*$');
+  static final RegExp NON_IDENTIFIER_CHAR = new RegExp(r'[^A-Za-z_0-9$]');
+
   /**
    * Map from top-level or static elements to their unique identifiers provided
    * by [getName].
    *
    * Invariant: Keys must be declaration elements.
    */
   final Compiler compiler;
   final Map<Element, String> globals;
   final Map<String, LibraryElement> shortPrivateNameOwners;
 
@@ skipping 194 matching lines @@
       }
     }
   }
 
   /**
    * Returns the internal name used for an invocation mirror of this selector.
    */
   String invocationMirrorInternalName(Selector selector)
       => invocationName(selector);
 
-  String instanceFieldName(Element element) {
+  /**
+   * Returns name of accessor (root to getter and setter) for a static or
+   * instance field.
+   */
+  String fieldAccessorName(Element element) {
+    return element.isInstanceMember()
+        ? instanceFieldAccessorName(element)
+        : getNameOfField(element);
+  }
+
+  /**
+   * Returns name of the JavaScript property used to store a static or instance
+   * field.
+   */
+  String fieldPropertyName(Element element) {
+    return element.isInstanceMember()
+        ? instanceFieldPropertyName(element)
+        : getNameOfField(element);
+  }
+
+  /**
+   * Returns name of accessor (root to getter and setter) for an instance field.
+   */
+  String instanceFieldAccessorName(Element element) {
     String proposedName = privateName(element.getLibrary(), element.name);
     return getMappedInstanceName(proposedName);
   }
 
-  // Construct a new name for the element based on the library and class it is
-  // in.  The name here is not important, we just need to make sure it is
-  // unique.  If we are minifying, we actually construct the name from the
-  // minified versions of the class and instance names, but the result is
-  // minified once again, so that is not visible in the end result.
-  String shadowedFieldName(Element fieldElement) {
-    // Check for following situation: Native field ${fieldElement.name} has
-    // fixed JSName ${fieldElement.nativeName()}, but a subclass shadows this
-    // name.  We normally handle that by renaming the superclass field, but we
-    // can't do that because native fields have fixed JavaScript names.
-    // In practice this can't happen because we can't inherit from native
-    // classes.
-    assert (!fieldElement.hasFixedBackendName());
+  /**
+   * Returns name of the JavaScript property used to store an instance field.
+   */
+  String instanceFieldPropertyName(Element element) {
+    if (element.hasFixedBackendName()) {
+      return element.fixedBackendName();
+    }
+    // If a class is used anywhere as a mixin, we must make the name unique so
+    // that it does not accidentally shadow.  Also, the mixin name must be
+    // constant over all mixins.
+    if (compiler.world.isUsedAsMixin(element.getEnclosingClass()) ||
+        shadowingAnotherField(element)) {
+      // Construct a new name for the element based on the library and class it
+      // is in.  The name here is not important, we just need to make sure it is
+      // unique.  If we are minifying, we actually construct the name from the
+      // minified version of the class name, but the result is minified once
+      // again, so that is not visible in the end result.
+      String libraryName = getNameOfLibrary(element.getLibrary());
+      String className = getNameOfClass(element.getEnclosingClass());
+      String instanceName = privateName(element.getLibrary(), element.name);
+      return getMappedInstanceName('$libraryName\$$className\$$instanceName');
+    }
 
-    String libraryName = getNameOfLibrary(fieldElement.getLibrary());
-    String className = getNameOfClass(fieldElement.getEnclosingClass());
-    String instanceName = instanceFieldName(fieldElement);
-    return getMappedInstanceName('$libraryName\$$className\$$instanceName');
+    String proposedName = privateName(element.getLibrary(), element.name);
+    return getMappedInstanceName(proposedName);
+  }
+
+
+  bool shadowingAnotherField(Element element) {
+    return element.getEnclosingClass().hasFieldShadowedBy(element);
   }
 
   String setterName(Element element) {
     // We dynamically create setters from the field-name. The setter name must
     // therefore be derived from the instance field-name.
     LibraryElement library = element.getLibrary();
     String name = getMappedInstanceName(privateName(library, element.name));
     return '$setterPrefix$name';
   }
 
@@ skipping 109 matching lines @@
       LibraryElement library = element;
       name = library.getLibraryOrScriptName();
       if (name.contains('.')) {
         // For libraries that have a library tag, we use the last part
         // of the fully qualified name as their base name. For all other
         // libraries, we use the first part of their filename.
         name = library.hasLibraryName()
             ? name.substring(name.lastIndexOf('.') + 1)
             : name.substring(0, name.indexOf('.'));
       }
+      // The filename based name can contain all kinds of nasty characters. Make
+      // sure it is an identifier.
+      if (!IDENTIFIER.hasMatch(name)) {
+        name = name.replaceAllMapped(NON_IDENTIFIER_CHAR,
+            (match) => match[0].codeUnitAt(0).toRadixString(16));
+        if (!IDENTIFIER.hasMatch(name)) {  // e.g. starts with digit.
+          name = 'lib_$name';
+        }
+      }
     } else {
       name = element.name;
     }
     return name;
   }
 
   String getInterceptorSuffix(Iterable<ClassElement> classes) {
     String abbreviate(ClassElement cls) {
       if (cls == compiler.objectClass) return "o";
       JavaScriptBackend backend = compiler.backend;
@@ skipping 106 matching lines @@
   String getNameX(Element element) {
     if (element.isInstanceMember()) {
       if (element.kind == ElementKind.GENERATIVE_CONSTRUCTOR_BODY
           || element.kind == ElementKind.FUNCTION) {
         return instanceMethodName(element);
       } else if (element.kind == ElementKind.GETTER) {
         return getterName(element);
       } else if (element.kind == ElementKind.SETTER) {
         return setterName(element);
       } else if (element.kind == ElementKind.FIELD) {
-        return instanceFieldName(element);
+        compiler.internalError(
+            'use instanceFieldPropertyName or instanceFieldAccessorName',
+            node: element.parseNode(compiler));
       } else {
         compiler.internalError('getName for bad kind: ${element.kind}',
                                node: element.parseNode(compiler));
       }
     } else {
       // Use declaration element to ensure invariant on [globals].
       element = element.declaration;
       // Dealing with a top-level or static element.
       String cached = globals[element];
       if (cached != null) return cached;
@@ skipping 606 matching lines @@
         if (!first) {
           sb.write('_');
         }
         sb.write('_');
         visit(link.head);
         first = true;
       }
     }
   }
 }