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.
 
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
 final bool REPORT_EXCESS_RESOLUTION = false;
 
+/**
+ * If true, trace information on pass2 optimizations.
+ */
+final bool REPORT_PASS2_OPTIMIZATIONS = false;
+
 class WorkItem {
   final Element element;
   TreeElements resolutionTree;
   bool allowSpeculativeOptimization = true;
   List<HTypeGuard> guards = const <HTypeGuard>[];
 
   WorkItem(this.element, this.resolutionTree);
 
   bool isAnalyzed() => resolutionTree !== null;
 
@@ skipping 128 matching lines @@
   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 233 matching lines @@
     // should know this.
     world.populate(this, libraries.getValues());
 
     log('Resolving...');
     backend.enqueueHelpers(enqueuer.resolution);
     processQueue(enqueuer.resolution, main);
     log('Resolved ${enqueuer.resolution.resolvedElements.length} elements.');
 
     log('Compiling...');
     processQueue(enqueuer.codegen, main);
+    log("Recompiling ${enqueuer.codegen.recompilationCandidates.length} "
+        "methods...");
+    processRecompilationQueue(enqueuer.codegen);
     log('Compiled ${codegenWorld.generatedCode.length} methods.');
 
     backend.assembleProgram();
 
     checkQueues();
   }
 
   processQueue(Enqueuer world, Element main) {
     backend.processNativeClasses(world, libraries.getValues());
     world.addToWorkList(main);
     codegenProgress.reset();
     world.forEach((WorkItem work) {
       withCurrentElement(work.element, () => work.run(this, world));
     });
     world.queueIsClosed = true;
     assert(world.checkNoEnqueuedInvokedInstanceMethods());
     world.registerFieldClosureInvocations();
   }
 
+  processRecompilationQueue(Enqueuer world) {
+    pass = 2;
+    while (!world.recompilationCandidates.isEmpty()) {
+      WorkItem work = world.recompilationCandidates.next();
+      var oldCode = world.universe.generatedCode[work.element];
+      world.universe.generatedCode.remove(work.element);
+      withCurrentElement(work.element, () => work.run(this, world));
+      var newCode = world.universe.generatedCode[work.element];
+      if (REPORT_PASS2_OPTIMIZATIONS && newCode != oldCode) {
+        log("Pass 2 optimization:");
+        log("Before:\n$oldCode");
+        log("After:\n$newCode");
+      }
+    }
+  }
+
   /**
    * Perform various checks of the queues. This includes checking that
    * the queues are empty (nothing was added after we stopped
    * processing the quese). Also compute the number of methods that
    * were resolved, but not compiled (aka excess resolution).
    */
   checkQueues() {
     for (var world in [enqueuer.resolution, enqueuer.codegen]) {
       world.forEach((WorkItem work) {
         internalErrorOnElement(work.element, "Work list is not empty.");
@@ skipping 124 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 115 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);
   }
 }