Fix reintroduction of global variables that have been deleted.

src/x64/stub-cache-x64.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
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@@ skipping 2420 matching lines @@
   //  -- rdx    : receiver
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   // Check that the map of the global has not changed.
   __ Cmp(FieldOperand(rdx, HeapObject::kMapOffset),
          Handle<Map>(object->map()));
   __ j(not_equal, &miss);
 
+  // Check that the value in the cell is not the hole. If it is, this
+  // cell could have been deleted and reintroducing the global needs
+  // to update the property details in the property dictionary of the
+  // global object. We bail out to the runtime system to do that.
+  __ Move(rbx, Handle<JSGlobalPropertyCell>(cell));
+  __ LoadRoot(kScratchRegister, Heap::kTheHoleValueRootIndex);
+  __ cmpq(kScratchRegister,

[Kevin Millikin (Chromium), 2011/01/27 05:27:54]

I think theres a compare root function on x64 (and possibly ARM?)

+          FieldOperand(rbx, JSGlobalPropertyCell::kValueOffset));
+  __ j(equal, &miss);
+
   // Store the value in the cell.
-  __ Move(rcx, Handle<JSGlobalPropertyCell>(cell));
-  __ movq(FieldOperand(rcx, JSGlobalPropertyCell::kValueOffset), rax);
+  __ movq(FieldOperand(rbx, JSGlobalPropertyCell::kValueOffset), rax);
 
   // Return the value (register rax).
   __ IncrementCounter(&Counters::named_store_global_inline, 1);
   __ ret(0);
 
   // Handle store cache miss.
   __ bind(&miss);
   __ IncrementCounter(&Counters::named_store_global_inline_miss, 1);
   Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Miss));
   __ Jump(ic, RelocInfo::CODE_TARGET);
@@ skipping 965 matching lines @@
   __ TailCallRuntime(Runtime::kSetProperty, 3, 1);
 
   return GetCode(flags);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64