nt # Enter a description of the change.

runtime/vm/code_generator.cc

 // 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.
 
 #include "vm/code_generator.h"
 
 #include "vm/assembler.h"
 #include "vm/ast.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
@@ skipping 1430 matching lines @@
 // This is called from function that needs to be optimized.
 // The requesting function can be already optimized (reoptimization).
 // Returns the Code object where to continue execution.
 DEFINE_RUNTIME_ENTRY(OptimizeInvokedFunction, 1) {
   const Function& function = Function::CheckedHandle(zone,
                                                      arguments.ArgAt(0));
   ASSERT(!function.IsNull());
   ASSERT(function.HasCode());
 
   if (CanOptimizeFunction(function, isolate)) {
-    // Reset usage counter for reoptimization before calling optimizer to
-    // prevent recursive triggering of function optimization.
-    function.set_usage_counter(0);
     if (FLAG_background_compilation) {
+      // Reduce the chance of triggering optimization while the function is
+      // being optimized in the background. INT_MIN should ensure that it takes
+      // long time to trigger optimization.
+      // Note that the background compilation queue rejects duplicate entries.
+      function.set_usage_counter(INT_MIN);
       BackgroundCompiler::EnsureInit(thread);
       ASSERT(isolate->background_compiler() != NULL);
       isolate->background_compiler()->CompileOptimized(function);
       // Continue in the same code.
       arguments.SetReturn(Code::Handle(zone, function.CurrentCode()));
       return;
     }
+
+    // Reset usage counter for reoptimization before calling optimizer to
+    // prevent recursive triggering of function optimization.
+    function.set_usage_counter(0);
     if (FLAG_trace_compiler) {
       if (function.HasOptimizedCode()) {
         THR_Print("ReCompiling function: '%s' \n",
                   function.ToFullyQualifiedCString());
       }
     }
     const Error& error = Error::Handle(
         zone, Compiler::CompileOptimizedFunction(thread, function));
     if (!error.IsNull()) {
       Exceptions::PropagateError(error);
@@ skipping 363 matching lines @@
   const intptr_t elm_size = old_data.ElementSizeInBytes();
   const TypedData& new_data =
       TypedData::Handle(TypedData::New(cid, new_size, Heap::kOld));
   TypedData::Copy(new_data, 0, old_data, 0, old_size * elm_size);
   typed_data_cell.SetAt(0, new_data);
   arguments.SetReturn(new_data);
 }
 
 
 }  // namespace dart