Patch CEntry stub to swallow exception if liveedit/restart frame needs it.

src/debug.h

Index: src/debug.h
diff --git a/src/debug.h b/src/debug.h
index 2b5f43ab4959cc4b5cf28a9b0323fc689884344e..92da1e2d3504c83911363ebd9d93da57001c7e8f 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -369,7 +369,8 @@ class Debug {
     k_after_break_target_address,
     k_debug_break_return_address,
     k_debug_break_slot_address,
-    k_restarter_frame_function_pointer
+    k_restarter_frame_function_pointer,
+    k_c_entry_frame_to_ignore_exception
   };
 
   // Support for setting the address to jump to when returning from break point.
@@ -381,6 +382,14 @@ class Debug {
     return reinterpret_cast<Address*>(address);
   }
 
+  void set_c_entry_frame_to_ignore_exception(Address fp) {
+    thread_local_.c_entry_frame_to_ignore_exception_ = fp;
+  }
+
+  Address* c_entry_frame_to_ignore_exception_address() {
+    return &thread_local_.c_entry_frame_to_ignore_exception_;
+  }
+
   // Support for saving/restoring registers when handling debug break calls.
   Object** register_address(int r) {
     return &registers_[r];
@@ -616,6 +625,10 @@ class Debug {
     // of the pointer to function being restarted. Otherwise (most of the time)
     // stores NULL. This pointer is used with 'step in' implementation.
     Object** restarter_frame_function_pointer_;
+
+    // Store fp of CEntry frame, that should swallow exception and return
+    // normally (because calling frame has already been patched).
+    Address c_entry_frame_to_ignore_exception_;
   };
 
   // Storage location for registers when handling debug break calls
@@ -1022,6 +1035,10 @@ class Debug_Address {
     return Debug_Address(Debug::k_restarter_frame_function_pointer);
   }
 
+  static Debug_Address CEntryFrameToIgnoreException() {
+    return Debug_Address(Debug::k_c_entry_frame_to_ignore_exception);
+  }
+
   Address address(Isolate* isolate) const {
     Debug* debug = isolate->debug();
     switch (id_) {
@@ -1034,6 +1051,9 @@ class Debug_Address {
       case Debug::k_restarter_frame_function_pointer:
         return reinterpret_cast<Address>(
             debug->restarter_frame_function_pointer_address());
+      case Debug::k_c_entry_frame_to_ignore_exception:
+        return reinterpret_cast<Address>(
+            debug->c_entry_frame_to_ignore_exception_address());
       default:
         UNREACHABLE();
         return NULL;