dart2dart Preproces placeholders instead of renaming them lazily,

lib/compiler/implementation/dart_backend/renamer.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Renames only top-level elements that would let to ambiguity if not renamed.
  * TODO(smok): Make sure that top-level fields are correctly renamed.
  */
 class ConflictingRenamer {
   final Compiler compiler;
+  final PlaceholderCollector placeholderCollector;
   final Map<LibraryElement, Map<String, String>> renamed;
   final Set<String> usedTopLevelIdentifiers;
   final Map<LibraryElement, String> imports;
-  final Map<Node, Placeholder> placeholders;
+  final Map<Node, String> renames;
   int privateNameCounter = 0;
 
-  ConflictingRenamer(this.compiler, this.placeholders) :
+  ConflictingRenamer(this.compiler, this.placeholderCollector) :
       renamed = new Map<LibraryElement, Map<String, String>>(),
       usedTopLevelIdentifiers = new Set<String>(),
-      imports = new Map<LibraryElement, String>() {
+      imports = new Map<LibraryElement, String>(),
+      renames = new Map<Node, String>() {
     // Rename main() right now so that nobody takes its place.
     renameElement(compiler.mainApp.find(Compiler.MAIN));
+
+    // Process local placeholders.
+    placeholderCollector.localPlaceholders.forEach(
+        (Element element, Map<Node, LocalPlaceholder> localPlaceholders) {
+          localPlaceholders.forEach((Node node, LocalPlaceholder placeholder) {
+            // TODO(smok): Check for conflicts with class fields and take usages
+            // into account.
+            renames[node] = placeholder.identifier;
+          });
+        });
+    // Process element placeholders.
+    renamePlaceholders(placeholderCollector.elementPlaceholders,
+        (ElementPlaceholder placeholder) => renameElement(placeholder.element));
+    // Process null placeholders.
+    renamePlaceholders(placeholderCollector.nullPlaceholders,
+        (NullPlaceholder placeholder) => '');
+    // Process private placeholders.
+    renamePlaceholders(placeholderCollector.privatePlaceholders,
+        (PrivatePlaceholder placeholder) =>
+            renamePrivateIdentifier(placeholder.library,
+                placeholder.node.source.slowToString()));
+    // Process unresolved placeholders.
+    renamePlaceholders(placeholderCollector.unresolvedPlaceholders,
+        (UnresolvedPlaceholder placeholder) =>
+            generateUniqueName('Unresolved'));
+  }
+
+  void renamePlaceholders(Map<Node, Placeholder> placeholders,
+      String rename(Placeholder placeholder)) {
+    placeholders.forEach((Node node, Placeholder placeholder) {
+      renames[node] = rename(placeholder);
+    });
   }
 
   // Renamer implementation.
-  String rename(Node node) {
-    Placeholder placeholder = placeholders[node];
-    return (placeholder !== null) ? placeholder.rename(this) : null;
-  }
+  String rename(Node node) => renames[node];
 
   String getName(LibraryElement library, String originalName, renamer) =>
       renamed.putIfAbsent(library, () => <String>{})
           .putIfAbsent(originalName, renamer);
 
   String renamePrivateIdentifier(LibraryElement library, String id) =>
       getName(library, id, () => '_${privateNameCounter++}${id}');
 
   String generateUniqueName(name) {
     while (usedTopLevelIdentifiers.contains(name)) name = 'p_$name';
     usedTopLevelIdentifiers.add(name);
     return name;
   }
 
-  // TODO(smok): Check for conflicts with class fields and take usages
-  // into account.
-  String renameLocalIdentifier(FunctionElement scope, String identifier) =>
-      identifier;
-
   String renameElement(Element element) {
     assert(element.isTopLevel());
     // TODO(smok): Make sure that the new name does not conflict with existing
     // local identifiers.
     String originalName = element.name.slowToString();
     LibraryElement library = element.getLibrary();
     if (library === compiler.coreLibrary) return originalName;
     if (isDartCoreLib(compiler, library)) {
       final prefix =
           imports.putIfAbsent(library, () => generateUniqueName('p'));
       return '$prefix.$originalName';
     }
 
     return getName(library, originalName,
                    () => generateUniqueName(originalName));
   }
 }