Details wrt parallel recompilation.

src/compiler.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 945 matching lines @@
   }
 
   if (isolate->has_pending_exception()) {
     isolate->clear_pending_exception();
   }
 }
 
 
 void Compiler::InstallOptimizedCode(OptimizingCompiler* optimizing_compiler) {
   SmartPointer<CompilationInfo> info(optimizing_compiler->info());
+  // Function may have been optimized meanwhile by OSR.
+  if (FLAG_use_osr) {
+    // Function may have already been optimized meanwhile by OSR.
+    if (!info->code().is_null() &&
+        info->code()->kind() == Code::OPTIMIZED_FUNCTION) {
+      return;
+    }
+    // OSR may also have caused optimization to be disabled.
+    if (info->shared_info()->optimization_disabled()) return;
+  }
+
   Isolate* isolate = info->isolate();
   VMState state(isolate, PARALLEL_COMPILER);
   Logger::TimerEventScope timer(
       isolate, Logger::TimerEventScope::v8_recompile_synchronous);
   // If crankshaft succeeded, install the optimized code else install
   // the unoptimized code.
   OptimizingCompiler::Status status = optimizing_compiler->last_status();
   if (status != OptimizingCompiler::SUCCEEDED) {
     optimizing_compiler->info()->set_bailout_reason(
         "failed/bailed out last time");
@@ skipping 144 matching lines @@
     }
   }
 
   GDBJIT(AddCode(Handle<String>(shared->DebugName()),
                  Handle<Script>(info->script()),
                  Handle<Code>(info->code()),
                  info));
 }
 
 } }  // namespace v8::internal