This is a little experiment to move Failure to a superclass above Object...

src/x64/macro-assembler-x64.cc

 // Copyright 2010 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 496 matching lines @@
       extensions_address);
 
   Object* result = NULL;
   Label write_back;
   movq(kScratchRegister, extensions_address);
   cmpq(Operand(kScratchRegister, kExtensionsOffset), Immediate(0));
   j(equal, &write_back);
   push(saved);
   if (gc_allowed) {
     CallRuntime(Runtime::kDeleteHandleScopeExtensions, 0);
+    { TryAllocation t =
+          TryCallRuntime(Runtime::kDeleteHandleScopeExtensions, 0);
+      if (!t->ToObject(&result)) return t;
+    }
   } else {
-    result = TryCallRuntime(Runtime::kDeleteHandleScopeExtensions, 0);
-    if (result->IsFailure()) return result;
   }
   pop(saved);
   movq(kScratchRegister, extensions_address);
 
   bind(&write_back);
   pop(Operand(kScratchRegister, kLimitOffset));
   pop(Operand(kScratchRegister, kNextOffset));
   pop(scratch);
   SmiToInteger32(scratch, scratch);
   movq(Operand(kScratchRegister, kExtensionsOffset), scratch);
@@ skipping 1693 matching lines @@
   CPU::FlushICache(address_, size_);
 
   // Check that the code was patched as expected.
   ASSERT(masm_.pc_ == address_ + size_);
   ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64