Interrupts must not mask stack overflow.

src/execution.h

Index: src/execution.h
diff --git a/src/execution.h b/src/execution.h
index 16bc6257e262330afbbc6738472bf6091e9b5ed9..74d0feb75c7169bacb1b8e0a427358e74e641733 100644
--- a/src/execution.h
+++ b/src/execution.h
@@ -145,8 +145,6 @@ class StackGuard V8_FINAL {
   // it has been set up.
   void ClearThread(const ExecutionAccess& lock);
 
-  bool IsStackOverflow();
-
 #define INTERRUPT_LIST(V)                                       \
   V(DEBUGBREAK, DebugBreak)                                     \
   V(DEBUGCOMMAND, DebugCommand)                                 \
@@ -266,6 +264,11 @@ enum InterruptFlag {
     int interrupt_flags_;
   };
 
+  class StackPointer {
+   public:
+    inline uintptr_t address() { return reinterpret_cast<uintptr_t>(this); }
+  };
+
   // TODO(isolates): Technically this could be calculated directly from a
   //                 pointer to StackGuard.
   Isolate* isolate_;