VM: Support bootstrapping core libraries from Kernel binaries instead of source.

tools/patch_sdk.dart

 #!/usr/bin/env 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.
 
 /// Command line tool to merge the SDK libraries and our patch files.
 /// This is currently designed as an offline tool, but we could automate it.
 
 import 'dart:io';
 import 'dart:math' as math;
@@ skipping 246 matching lines @@
   // the other files.
   final patchFinder = new PatchFinder.parseAndVisit(name, patchContents);
 
   // Merge `external` declarations with the corresponding `@patch` code.
   for (var partContent in partsContents) {
     var partEdits = new StringEditBuffer(partContent);
     var partUnit = parseCompilationUnit(partContent);
     partUnit.accept(new PatchApplier(partEdits, patchFinder));
     results.add(partEdits);
   }
+
+  if (patchFinder.patches.length != patchFinder.applied.length) {
+    print('Some elements marked as @patch do not have corresponding elements:');
+    for (var patched in patchFinder.patches.keys) {
+      if (!patchFinder.applied.contains(patched)) {
+        print('*** ${patched}');
+      }
+    }
+    throw "Failed to apply all @patch-es";
+  }
+
   return new List<String>.from(results.map((e) => e.toString()));
 }
 
 /// Merge `@patch` declarations into `external` declarations.
 class PatchApplier extends GeneralizingAstVisitor {
   final StringEditBuffer edits;
   final PatchFinder patch;
 
   bool _isLibrary = true; // until proven otherwise.
 
@@ skipping 59 matching lines @@
     for (var member in mergeMembers) {
       var code = patch.contents.substring(member.offset, member.end);
       edits.insert(pos, '\n\n  ' + code);
     }
   }
 
   void _maybePatch(AstNode node) {
     if (node is FieldDeclaration) return;
 
     var externalKeyword = (node as dynamic).externalKeyword;
-    if (externalKeyword == null) return;
 
     var name = _qualifiedName(node);
     var patchNode = patch.patches[name];
     if (patchNode == null) {
-      print('warning: patch not found for $name: $node');
+      if (externalKeyword != null) {
+        print('warning: patch not found for $name: $node');
+      }
       return;
     }
+    patch.applied.add(name);
 
     Annotation patchMeta = patchNode.metadata.lastWhere(_isPatchAnnotation);
     int start = patchMeta.endToken.next.offset;
     var code = patch.contents.substring(start, patchNode.end);
 
     // For some node like static fields, the node's offset doesn't include
     // the external keyword. Also starting from the keyword lets us preserve
     // documentation comments.
-    edits.replace(externalKeyword.offset, node.end, code);
+    edits.replace(externalKeyword?.offset ?? node.offset, node.end, code);
   }
 }
 
 class PatchFinder extends GeneralizingAstVisitor {
   final String contents;
   final CompilationUnit unit;
 
   final Map patches = <String, Declaration>{};
   final Map mergeMembers = <String, List<ClassMember>>{};
   final List mergeDeclarations = <CompilationUnitMember>[];
+  final Set<String> applied = new Set<String>();
 
   PatchFinder.parseAndVisit(String name, String contents)
       : contents = contents,
         unit = parseCompilationUnit(contents, name: name) {
     visitCompilationUnit(unit);
   }
 
   @override
   visitCompilationUnitMember(CompilationUnitMember node) {
     mergeDeclarations.add(node);
@@ skipping 144 matching lines @@
     if (diff != 0) return diff;
     return end - other.end;
   }
 }
 
 List<SdkLibrary> _getSdkLibraries(String contents) {
   var libraryBuilder = new SdkLibrariesReader_LibraryBuilder(true);
   parseCompilationUnit(contents).accept(libraryBuilder);
   return libraryBuilder.librariesMap.sdkLibraries;
 }