Parallel recompilation: fewer handle dereferences and tighter checks.

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index e6f6d167f15e0a095b9ddf37dbec0959e79ddbb1..d6770ccf28634a5241c6bb9b4177cfe364562d2c 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -988,8 +988,9 @@ class Isolate {
 
   int* code_kind_statistics() { return code_kind_statistics_; }
 
-  bool allow_handle_deref() { return allow_handle_deref_; }
-  void set_allow_handle_deref(bool allow) { allow_handle_deref_ = allow; }
+  bool AllowHandleDereference();
+
+  void SetAllowHandleDereference(bool allow);
 #endif
 
 #if defined(V8_TARGET_ARCH_ARM) && !defined(__arm__) || \
@@ -1305,7 +1306,8 @@ class Isolate {
   JSObject::SpillInformation js_spill_information_;
   int code_kind_statistics_[Code::NUMBER_OF_KINDS];
 
-  bool allow_handle_deref_;
+  bool allow_compiler_thread_handle_deref_;
+  bool allow_execution_thread_handle_deref_;
 #endif
 
 #ifdef ENABLE_DEBUGGER_SUPPORT