Add renames in output when using the mirror helper library.

sdk/lib/_internal/compiler/implementation/mirror_renamer/renamer.dart

 // Copyright (c) 2013, 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 mirror_renamer;
 
 class MirrorRenamer {
-  static const String MIRROR_HELPER_CLASS = 'MirrorHelper';
-  static const String MIRROR_HELPER_GET_NAME_FUNCTION = 'getName';
-  static const String MIRROR_HELPER_LIBRARY_NAME = 'mirror_helper.dart';
-  static const String MIRROR_HELPER_LIBRARY_PREFIX = 'm';
-  static const String MIRROR_HELPER_CLASS_FULLY_QUALIFIED_NAME =
-      '$MIRROR_HELPER_LIBRARY_PREFIX.$MIRROR_HELPER_CLASS';
+  static const String MIRROR_HELPER_GET_NAME_FUNCTION = 'helperGetName';
+  static const String MIRROR_HELPER_LIBRARY_NAME = '_mirror_helper';
+  static const String MIRROR_HELPER_SYMBOLS_MAP_NAME = '_SYMBOLS';
 
-  static void handleStaticSend(Map<Node, String> renames, Element element,
-                               Send node, Compiler compiler) {
+  Map<String, SourceString> symbols = new Map<String, SourceString>();

[Johnni Winther, 2013/08/23 09:25:19]

Document this.

[zarah, 2013/08/23 16:16:37]

Done.

+  List<Node> mirrorSystemGetNameNodes = <Node>[];

[Johnni Winther, 2013/08/23 09:25:19]

Document this.

[zarah, 2013/08/23 16:16:37]

Done.

+  /**
+   *  Initialized when the placeholderCollector collects the FunctionElement
+   *  backend.mirrorHelperGetNameFunction which represents the helperGetName
+   *  function in _mirror_helper.
+   */
+  FunctionExpression mirrorHelperGetNameFunctionNode;
+  Compiler compiler;
+  DartBackend backend;
+
+  MirrorRenamer(this.compiler, this.backend);
+
+  void registerStaticSend(Element element, Send node) {
   if (element == compiler.mirrorSystemGetNameFunction) {
-    renames[node.selector] = MIRROR_HELPER_GET_NAME_FUNCTION;
-    renames[node.receiver] = MIRROR_HELPER_CLASS_FULLY_QUALIFIED_NAME;
-    }
+    mirrorSystemGetNameNodes.add(node);
+  }
  }
 
-  static void addMirrorHelperImport(Map<LibraryElement, String> imports) {
-    Uri mirrorHelperUri = new Uri(path: MIRROR_HELPER_LIBRARY_NAME);
-    // TODO(zarah): Remove this hack! LibraryElementX should not be created
-    // outside the library loader. When actual mirror helper library
-    // is created, change to load that.
-    LibraryElement mirrorHelperLib = new LibraryElementX(
-        new Script(mirrorHelperUri, null));
-    imports.putIfAbsent(mirrorHelperLib, () => MIRROR_HELPER_LIBRARY_PREFIX);
+  void registerHelperFunction(Element element, Node node) {
+    if (element == backend.mirrorHelperGetNameFunction) {
+      mirrorHelperGetNameFunctionNode = node;
+    }
   }
-}
+
+  /**
+   * Adds a toplevel node to the output containing a map from the mangled
+   * to the unmangled names and replaces calls to MirrorSystem.getName()
+   * with calls to the corresponding wrapper from _mirror_helper which has
+   * been added during resolution.
+   */
+  void addRenames(Map<Node, String> renames, List<Node> topLevelNodes) {

[Johnni Winther, 2013/08/23 09:25:19]

Document the parameters.

[zarah, 2013/08/23 16:16:37]

Done.

+    symbols = new Map<String, SourceString>();
+    String renameMapName;
+    FunctionElement getNameElement;
+
+    Node parse(String text) {
+      Token tokens = compiler.scanner.tokenize(text);
+      return compiler.parser.parseCompilationUnit(tokens);
+    }
+
+    // Add toplevel map containing all renames.
+    for (Node node in renames.keys) {
+      Identifier identifier = node.asIdentifier();
+      if (identifier != null) {
+        if (identifier.source ==
+            const SourceString(MIRROR_HELPER_SYMBOLS_MAP_NAME)) {

[Johnni Winther, 2013/08/23 09:25:19]

Why is this special-cased? And why is it not put in [symbol]? What happens if
the user code has an identifier '_SYMBOLS'?

[zarah, 2013/08/23 16:16:37]

In theory it is not a problem since all source code names will be renamed to the
same mangled name. But for robustness, this is now changed so it compares the
node to the corresponding element.

+          renameMapName = renames[node];
+        } else {
+          symbols.putIfAbsent(renames[node], () => identifier.source);
+        }
+      }
+    }
+
+    StringBuffer sb = new StringBuffer('const $renameMapName = '
+        'const<String, SourceString>{');
+    bool first = true;
+    for (String mangledName in symbols.keys) {
+      if (!first) {
+        sb.write(',');
+      } else {
+        first = false;
+      }
+      sb.write("'$mangledName' : '${symbols[mangledName]}'");
+    }
+    sb.write('};');
+    topLevelNodes.add(parse(sb.toString()));
+
+    // Replace calls to Mirrorsystem.getName with calls to helper function.
+    getNameElement = backend.mirrorHelperLibrary.find(const
+         SourceString(MIRROR_HELPER_GET_NAME_FUNCTION));
+    Node getNameNode = getNameElement.parseNode(compiler);
+    mirrorSystemGetNameNodes.forEach((node) {
+      renames[node.selector] = renames[mirrorHelperGetNameFunctionNode.name];
+      renames[node.receiver] = '';
+    });
+  }
+}