Current custom call generators cannot cope with the case when receiver is not a JSArray.

src/ia32/stub-cache-ia32.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1223 matching lines @@
                                                CheckType check) {
   // ----------- S t a t e -------------
   //  -- ecx                 : name
   //  -- esp[0]              : return address
   //  -- esp[(argc - n) * 4] : arg[n] (zero-based)
   //  -- ...
   //  -- esp[(argc + 1) * 4] : receiver
   // -----------------------------------
   ASSERT(check == RECEIVER_MAP_CHECK);
 
+  // If object is not an array, bail out to regular call.
+  if (!object->IsJSArray()) {
+    return Heap::undefined_value();
+  }
+
   Label miss;
 
   // Get the receiver from the stack.
   const int argc = arguments().immediate();
   __ mov(edx, Operand(esp, (argc + 1) * kPointerSize));
 
   // Check that the receiver isn't a smi.
   __ test(edx, Immediate(kSmiTagMask));
   __ j(zero, &miss);
 
@@ skipping 128 matching lines @@
                                               CheckType check) {
   // ----------- S t a t e -------------
   //  -- ecx                 : name
   //  -- esp[0]              : return address
   //  -- esp[(argc - n) * 4] : arg[n] (zero-based)
   //  -- ...
   //  -- esp[(argc + 1) * 4] : receiver
   // -----------------------------------
   ASSERT(check == RECEIVER_MAP_CHECK);
 
+  // If object is not an array, bail out to regular call.
+  if (!object->IsJSArray()) {
+    return Heap::undefined_value();
+  }
+
   Label miss, empty_array, call_builtin;
 
   // Get the receiver from the stack.
   const int argc = arguments().immediate();
   __ mov(edx, Operand(esp, (argc + 1) * kPointerSize));
 
   // Check that the receiver isn't a smi.
   __ test(edx, Immediate(kSmiTagMask));
   __ j(zero, &miss);
 
@@ skipping 67 matching lines @@
   //  -- esp[0]              : return address
   //  -- esp[(argc - n) * 4] : arg[n] (zero-based)
   //  -- ...
   //  -- esp[(argc + 1) * 4] : receiver
   // -----------------------------------
 
   SharedFunctionInfo* function_info = function->shared();
   if (function_info->HasCustomCallGenerator()) {
     CustomCallGenerator generator =
         ToCData<CustomCallGenerator>(function_info->function_data());
-    return generator(this, object, holder, function, name, check);
+    Object* result = generator(this, object, holder, function, name, check);
+    // undefined means bail out to regular compiler.
+    if (!result->IsUndefined()) {
+      return result;
+    }
   }
 
   Label miss_in_smi_check;
 
   // Get the receiver from the stack.
   const int argc = arguments().immediate();
   __ mov(edx, Operand(esp, (argc + 1) * kPointerSize));
 
   // Check that the receiver isn't a smi.
   if (check != NUMBER_CHECK) {
@@ skipping 995 matching lines @@
   __ jmp(generic_construct_stub, RelocInfo::CODE_TARGET);
 
   // Return the generated code.
   return GetCode();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal