Create frequently used symbols in the vm isolate

vm/isolate.cc

Index: vm/isolate.cc
===================================================================
--- vm/isolate.cc	(revision 9729)
+++ vm/isolate.cc	(working copy)
@@ -20,6 +20,7 @@
 #include "vm/random.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
+#include "vm/symbols.h"
 #include "vm/thread.h"
 #include "vm/timer.h"
 #include "vm/visitor.h"
@@ -163,7 +164,10 @@
       stack_limit_(0),
       saved_stack_limit_(0),
       message_handler_(NULL),
-      spawn_data_(NULL) {
+      spawn_data_(NULL),
+      gc_prologue_callbacks_(),
+      gc_epilogue_callbacks_(),
+      symbols_(NULL) {
 }
 
 
@@ -178,6 +182,7 @@
   mutex_ = NULL;  // Fail fast if interrupts are scheduled on a dead isolate.
   delete message_handler_;
   message_handler_ = NULL;  // Fail fast if we send messages to a dead isolate.
+  delete symbols_;
 }
 
 void Isolate::SetCurrent(Isolate* current) {
@@ -411,6 +416,11 @@
   // Visit objects in the object store.
   object_store()->VisitObjectPointers(visitor);
 
+  // Visit cached symbols if any.
+  if (symbols() != NULL) {
+    symbols()->VisitObjectPointers(visitor);
+  }
+
   // Visit objects in the class table.
   class_table()->VisitObjectPointers(visitor);