Parallel recompilation: fix concurrency issues.

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7711 matching lines @@
   return function->code();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ParallelRecompile) {
   HandleScope handle_scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
   if (!AllowOptimization(isolate, function)) {
     function->ReplaceCode(function->shared()->code());
-    return function->code();
+    return isolate->heap()->undefined_value();
   }
   function->shared()->code()->set_profiler_ticks(0);
   ASSERT(FLAG_parallel_recompilation);
   Compiler::RecompileParallel(function);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_InstallRecompiledCode) {
   HandleScope handle_scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
-  if (!V8::UseCrankshaft()) return isolate->heap()->undefined_value();
-  ASSERT(FLAG_parallel_recompilation);
+  ASSERT(V8::UseCrankshaft() && FLAG_parallel_recompilation);
   OptimizingCompilerThread* opt_thread = isolate->optimizing_compiler_thread();
-  opt_thread->InstallOptimizedFunctions();
+  do {
+    // The function could have been marked for installing, but not queued just
+    // yet.  In this case, retry until installed.
+    opt_thread->InstallOptimizedFunctions();
+  } while (function->IsMarkedForInstallingRecompiledCode());
   return function->code();
 }
 
 
 class ActivationsFinder : public ThreadVisitor {
  public:
   explicit ActivationsFinder(JSFunction* function)
       : function_(function), has_activations_(false) {}
 
   void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
@@ skipping 5644 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal