As discussed on the phone, I'd like your thoughts on the...

src/codegen-ia32.cc

 // Copyright 2006-2008 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 4791 matching lines @@
   __ bind(&skip);
 
   __ ret(0);
 }
 
 
 void CEntryStub::GenerateCore(MacroAssembler* masm,
                               Label* throw_normal_exception,
                               Label* throw_out_of_memory_exception,
                               StackFrame::Type frame_type,
-                              bool do_gc) {
+                              bool do_gc,
+                              bool always_allocate_scope) {
   // eax: result parameter for PerformGC, if any
   // ebx: pointer to C function  (C callee-saved)
   // ebp: frame pointer  (restored after C call)
   // esp: stack pointer  (restored after C call)
   // edi: number of arguments including receiver  (C callee-saved)
   // esi: pointer to the first argument (C callee-saved)
 
   if (do_gc) {
     __ mov(Operand(esp, 0 * kPointerSize), eax);  // Result.
     __ call(FUNCTION_ADDR(Runtime::PerformGC), RelocInfo::RUNTIME_ENTRY);
   }
 
+  ExternalReference scope_depth =
+      ExternalReference::heap_always_allocate_scope_depth();
+  if (always_allocate_scope) {
+    __ inc(Operand::StaticVariable(scope_depth));
+  }
+
   // Call C function.
   __ mov(Operand(esp, 0 * kPointerSize), edi);  // argc.
   __ mov(Operand(esp, 1 * kPointerSize), esi);  // argv.
   __ call(Operand(ebx));
   // Result is in eax or edx:eax - do not destroy these registers!
 
+  if (always_allocate_scope) {
+    __ dec(Operand::StaticVariable(scope_depth));
+  }
+
   // Check for failure result.
   Label failure_returned;
   ASSERT(((kFailureTag + 1) & kFailureTagMask) == 0);
   __ lea(ecx, Operand(eax, 1));
   // Lower 2 bits of ecx are 0 iff eax has failure tag.
   __ test(ecx, Immediate(kFailureTagMask));
   __ j(zero, &failure_returned, not_taken);
 
   // Exit the JavaScript to C++ exit frame.
   __ LeaveExitFrame(frame_type);
@@ skipping 115 matching lines @@
 
   // Call into the runtime system. Collect garbage before the call if
   // running with --gc-greedy set.
   if (FLAG_gc_greedy) {
     Failure* failure = Failure::RetryAfterGC(0);
     __ mov(Operand(eax), Immediate(reinterpret_cast<int32_t>(failure)));
   }
   GenerateCore(masm, &throw_normal_exception,
                &throw_out_of_memory_exception,
                frame_type,
-               FLAG_gc_greedy);
+               FLAG_gc_greedy,
+               false);
 
   // Do space-specific GC and retry runtime call.
   GenerateCore(masm,
                &throw_normal_exception,
                &throw_out_of_memory_exception,
                frame_type,
-               true);
+               true,
+               false);
 
   // Do full GC and retry runtime call one final time.
   Failure* failure = Failure::InternalError();
   __ mov(Operand(eax), Immediate(reinterpret_cast<int32_t>(failure)));
   GenerateCore(masm,
                &throw_normal_exception,
                &throw_out_of_memory_exception,
                frame_type,
+               true,
                true);
 
   __ bind(&throw_out_of_memory_exception);
   GenerateThrowOutOfMemory(masm);
   // control flow for generated will not return.
 
   __ bind(&throw_normal_exception);
   GenerateThrowTOS(masm);
 }
 
@@ skipping 128 matching lines @@
 
   // Slow-case: Go through the JavaScript implementation.
   __ bind(&slow);
   __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal