Prototype re-compiling methods in dart2js

lib/compiler/implementation/compiler.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.
 
 class WorkItem {
   final Element element;
   TreeElements resolutionTree;
   bool allowSpeculativeOptimization = true;
   List<HTypeGuard> guards = const <HTypeGuard>[];
 
@@ skipping 93 matching lines @@
   ClassElement listClass;
 
   Element get currentElement() => _currentElement;
   withCurrentElement(Element element, f()) {
     Element old = currentElement;
     _currentElement = element;
     try {
       return f();
     } catch (CompilerCancelledException ex) {
       throw;
+    } catch (Pass2BailoutException ex) {
+      throw;
     } catch (var ex) {
       unhandledExceptionOnElement(element);
       throw;
     } finally {
       _currentElement = old;
     }
   }
 
   List<CompilerTask> tasks;
   ScannerTask scanner;
   DietParserTask dietParser;
   ParserTask parser;
   TreeValidatorTask validator;
   UnparseValidator unparseValidator;
   ResolverTask resolver;
   TypeCheckerTask checker;
   Backend backend;
   ConstantHandler constantHandler;
   EnqueueTask enqueuer;
+  int pass = 1;
 
   static final SourceString MAIN = const SourceString('main');
   static final SourceString NO_SUCH_METHOD = const SourceString('noSuchMethod');
   static final SourceString NO_SUCH_METHOD_EXCEPTION =
       const SourceString('NoSuchMethodException');
   static final SourceString START_ROOT_ISOLATE =
       const SourceString('startRootIsolate');
   bool enabledNoSuchMethod = false;
 
   Stopwatch codegenProgress;
@@ skipping 231 matching lines @@
 
   processQueue(Enqueuer world, Element main) {
     backend.processNativeClasses(world, libraries.getValues());
     world.addToWorkList(main);
     codegenProgress.reset();
     while (!world.queue.isEmpty()) {
       WorkItem work = world.queue.removeLast();
       withCurrentElement(work.element, () => work.run(this, world));
     }
     world.queueIsClosed = true;
+    log("Recompilation candidates queue length: "
+        "${world.recompilationCandidates.length}");
+    pass = 2;
+    while (!world.recompilationCandidates.isEmpty()) {
+      WorkItem work = world.recompilationCandidates.next();
+      var oldCode = world.universe.generatedCode[work.element];
+      world.universe.generatedCode.remove(work.element);
+      try {
+        withCurrentElement(work.element, () => work.run(this, world));
+      } catch (Pass2BailoutException ex) {
+        world.universe.generatedCode[work.element] = oldCode;
+      }
+      var newCode = world.universe.generatedCode[work.element];
+      if (newCode != oldCode) {
+        log("PASS 2 OPTIMIZATION:");
+        log("Before: $oldCode");
+        log("After: $newCode");
+      }
+    }
     assert(world.checkNoEnqueuedInvokedInstanceMethods());
     world.registerFieldClosureInvocations();
   }
 
   TreeElements analyzeElement(Element element) {
     assert(parser !== null);
     Node tree = parser.parse(element);
     validator.validate(tree);
     unparseValidator.check(element);
     TreeElements elements = resolver.resolve(element);
@@ skipping 62 matching lines @@
     if (message is TypeWarning) {
       // TODO(ahe): Don't supress these warning when the type checker
       // is more complete.
       if (message.message.kind === MessageKind.NOT_ASSIGNABLE) return;
       if (message.message.kind === MessageKind.MISSING_RETURN) return;
       if (message.message.kind === MessageKind.MAYBE_MISSING_RETURN) return;
       if (message.message.kind === MessageKind.ADDITIONAL_ARGUMENT) return;
       if (message.message.kind === MessageKind.METHOD_NOT_FOUND) return;
     }
     SourceSpan span = spanFromNode(node);
+
     reportDiagnostic(span, "${magenta('warning:')} $message", false);
   }
 
   reportError(Node node, var message) {
     SourceSpan span = spanFromNode(node);
     reportDiagnostic(span, "${red('error:')} $message", true);
     throw new CompilerCancelledException(message.toString());
   }
 
   abstract void reportDiagnostic(SourceSpan span, String message, bool fatal);
@@ skipping 77 matching lines @@
 class CompilerCancelledException implements Exception {
   final String reason;
   CompilerCancelledException(this.reason);
 
   String toString() {
     String banner = 'compiler cancelled';
     return (reason !== null) ? '$banner: $reason' : '$banner';
   }
 }
 
+class Pass2BailoutException implements Exception {
+  final String reason;
+  Pass2BailoutException(this.reason);
+
+  String toString() {
+    return 'Pass 2 not supported: $reason';
+  }
+}
+
 class Tracer {
   final bool enabled = false;
 
   const Tracer();
 
   void traceCompilation(String methodName) {
   }
 
   void traceGraph(String name, var graph) {
   }
@@ skipping 17 matching lines @@
     // invariant that endOffset > beginOffset, but for EOF the
     // charoffset of the next token may be [beginOffset]. This can
     // also happen for synthetized tokens that are produced during
     // error handling.
     final endOffset =
       Math.max((end.next !== null) ? end.next.charOffset : 0, beginOffset + 1);
     assert(endOffset > beginOffset);
     return f(beginOffset, endOffset);
   }
 }