Fix data race with interface caching

src/interface.h

Index: src/interface.h
diff --git a/src/interface.h b/src/interface.h
index 598d0381427095c4c9f31de6365385757ac328b0..4f0a204525336dfc12d87356a28214be9cf89caa 100644
--- a/src/interface.h
+++ b/src/interface.h
@@ -6,6 +6,7 @@
 #define V8_INTERFACE_H_
 
 #include "src/ast-value-factory.h"
+#include "src/base/lazy-instance.h"

[Benedikt Meurer, 2014/10/21 04:09:05]

No need for this include, see comment below.

 #include "src/zone-inl.h"  // For operator new.
 
 namespace v8 {
@@ -41,15 +42,9 @@ class Interface : public ZoneObject {
     return new(zone) Interface(NONE);
   }
 
-  static Interface* NewValue() {
-    static Interface value_interface(VALUE + FROZEN);  // Cached.
-    return &value_interface;
-  }
+  static Interface* NewValue();
 
-  static Interface* NewConst() {
-    static Interface value_interface(VALUE + CONST + FROZEN);  // Cached.
-    return &value_interface;
-  }
+  static Interface* NewConst();
 
   static Interface* NewModule(Zone* zone) {
     return new(zone) Interface(MODULE);
@@ -202,6 +197,11 @@ class Interface : public ZoneObject {
 #endif
   }
 
+  struct ValueCreate;
+  struct ConstCreate;
+  static base::LazyInstance<Interface*, ValueCreate>::type value_interface_;

[Benedikt Meurer, 2014/10/21 04:09:05]

Move the statics to the .cc file and hide them in namespace { }, i.e.

namespace {

base::LayzInstance<Interface*, Interface::ValueCreate>::type kValueInterface =
LAZY_INSTANCE_INITIALIZER;


base::LayzInstance<Interface*, Interface::ValueCreate>::type kConstInterface =
LAZY_INSTANCE_INITIALIZER;

}

[rossberg, 2014/10/21 10:42:52]

Done. Also changed them to do in-place construction.

+  static base::LazyInstance<Interface*, ConstCreate>::type const_interface_;
+
   Interface* Chase() {
     Interface* result = this;
     while (result->forward_ != NULL) result = result->forward_;