Parallel recompilation: fewer handle dereferences and tighter checks.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 5f7b3f2d3b6134b0c8518d76eca776ad1d8b98fd..24ec0566d5e3fe5f1251d0b717cb093c7ec69327 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1713,7 +1713,8 @@ Isolate::Isolate()
   memset(code_kind_statistics_, 0,
          sizeof(code_kind_statistics_[0]) * Code::NUMBER_OF_KINDS);
 
-  allow_handle_deref_ = true;
+  allow_compiler_thread_handle_deref_ = true;
+  allow_execution_thread_handle_deref_ = true;
 #endif
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
@@ -2321,6 +2322,33 @@ void Isolate::UnlinkDeferredHandles(DeferredHandles* deferred) {
 }
 
 
+#ifdef DEBUG
+bool Isolate::AllowHandleDereference() {
+  if (allow_execution_thread_handle_deref_ &&
+      allow_compiler_thread_handle_deref_) {
+    // Short-cut to avoid polling thread id.
+    return true;
+  }
+  if (FLAG_parallel_recompilation &&
+      optimizing_compiler_thread()->IsOptimizerThread()) {
+    return allow_compiler_thread_handle_deref_;
+  } else {
+    return allow_execution_thread_handle_deref_;
+  }
+}
+
+
+void Isolate::SetAllowHandleDereference(bool allow) {
+  if (FLAG_parallel_recompilation &&
+      optimizing_compiler_thread()->IsOptimizerThread()) {
+    allow_compiler_thread_handle_deref_ = allow;
+  } else {
+    allow_execution_thread_handle_deref_ = allow;
+  }
+}
+#endif
+
+
 HStatistics* Isolate::GetHStatistics() {
   if (hstatistics() == NULL) set_hstatistics(new HStatistics());
   return hstatistics();