Generators: Avoid calling into runtime if operand stack is empty

src/ia32/code-stubs-ia32.cc

 // Copyright 2012 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 5032 matching lines @@
   if (always_allocate_scope) {
     __ dec(Operand::StaticVariable(scope_depth));
   }
 
   // Runtime functions should not return 'the hole'.  Allowing it to escape may
   // lead to crashes in the IC code later.
   if (FLAG_debug_code) {
     Label okay;
     __ cmp(eax, masm->isolate()->factory()->the_hole_value());
     __ j(not_equal, &okay, Label::kNear);
-    // TODO(wingo): Currently SuspendJSGeneratorObject returns the hole.  Change
-    // to return another sentinel like a harmony symbol.
-    __ cmp(ebx, Immediate(ExternalReference(
-        Runtime::kSuspendJSGeneratorObject, masm->isolate())));
-    __ j(equal, &okay, Label::kNear);
     __ int3();
     __ bind(&okay);
   }
 
   // Check for failure result.
   Label failure_returned;
   STATIC_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));
@@ skipping 3026 matching lines @@
     __ jmp(generic_construct_stub, RelocInfo::CODE_TARGET);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32