Details wrt parallel recompilation.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 4970ec760871b793f71b5d8d3bd4dcfa086bd9c1..5cc3396c5128d8de08bca9e9c7d5f9de72130620 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1772,6 +1772,8 @@ void Isolate::Deinit() {
   if (state_ == INITIALIZED) {
     TRACE_ISOLATE(deinit);
 
+    if (FLAG_parallel_recompilation) optimizing_compiler_thread_.Stop();
+
     if (FLAG_sweeper_threads > 0) {
       for (int i = 0; i < FLAG_sweeper_threads; i++) {
         sweeper_thread_[i]->Stop();
@@ -1788,8 +1790,6 @@ void Isolate::Deinit() {
       delete[] marking_thread_;
     }
 
-    if (FLAG_parallel_recompilation) optimizing_compiler_thread_.Stop();
-
     if (FLAG_hydrogen_stats) HStatistics::Instance()->Print();
 
     // We must stop the logger before we tear down other components.
@@ -2198,6 +2198,11 @@ bool Isolate::Init(Deserializer* des) {
     FLAG_concurrent_sweeping = false;
     FLAG_parallel_sweeping = false;
   }
+  if (FLAG_parallel_recompilation &&
+      SystemThreadManager::NumberOfParallelSystemThreads(
+          SystemThreadManager::PARALLEL_RECOMPILATION) == 0) {
+    FLAG_parallel_recompilation = false;
+  }
   return true;
 }