Request for review: 8000797: NPG: is_pseudo_string_at() doesn't work

[Coleen Phillimore]

Thanks to John's feedback, I've modified this change again to revert 
back to my original change to zero out the Symbol* to indicate pseudo 
string (could be thought of as "patched string").   Also cleaned up 
unused constant pool Object constant and unused flags.   Reran all the 
tests.

http://cr.openjdk.java.net/~coleenp/8000797_2/

Thanks,
Coleen

On 2/20/2013 1:20 PM, Coleen Phillimore wrote:
> Since nobody replied to my code review request, I modified the change.
>
> Summary: Add JVM_CONSTANT_PseudoString in place of JVM_CONSTANT_Object 
> and use this tag to distinguish patched pseudo strings. The original 
> string is retained if it was present.
>
> I'm not sure how class file reconstitution for pseudo-strings is going 
> to work, but I thought it was prudent to leave the Symbol* in the slot 
> for the patched string.
>
> I noticed that JVM_CONSTANT_Object is no longer used so reused that 
> constant to be PseudoString.   I had an edit to go in the other 
> direction (if a pseudo-string is patched into a constant pool, make it 
> a JVM_CONSTANT_Object), but this didn't fully capture that the 
> constant pool slot also points to a Symbol. John or Christian, can you 
> confirm that you don't plan to use object constants anymore?
>
> open webrev at http://cr.openjdk.java.net/~coleenp/8000797/
> bug link at http://bugs.sun.com/view_bug.do?bug_id=8000797
>
> Tested with vm.quick.testlist (including parallel_class_loading and 
> mlvm tests) and java/lang/invoke and java/lang/instrument tests.
>
> Thanks,
> Coleen
>
> On 2/8/2013 4:59 PM, Coleen Phillimore wrote:
>> Summary: Null out the original string when patching constant pool 
>> with pseudo-string
>>
>> This call is_pseudo_string() conditionalized a pseudo_string_at() 
>> call, but since it always failed, it went to string_at() which 
>> returned the same thing.   The only thing that seems to treat 
>> pseudo-string and regular strings differently is the verifier. The 
>> verifier pushes an object for pseudo string vs. an object of type 
>> java/lang/String.
>>
>> open webrev at http://cr.openjdk.java.net/~coleenp/8000797/
>> bug link at http://bugs.sun.com/view_bug.do?bug_id=8000797
>>
>> Tested with vm.mlvm.testlists and java/lang/invoke tests.
>>
>> Thanks,
>> Coleen
>