RFR(XS): JDK-8068655 frame::safe_for_sender() computes incorrect sender_sp value for interpreted frames

[David Holmes]

Hi Fred,

On 30/01/2015 1:05 AM, Frederic Parain wrote:
> Hi Dean,
>
> When unextended_sp is not specified, it is set to the sp value.
>
> However, after your question, I realized that my fix was not
> correct but worked because the is_interpreted_frame_valid() had
> a bug too, it uses sp() where unextended_sp() should be used.

Just wondering what the implications of this bug would be? What code 
would be wrong, how would it manifest?

Thanks,
David

> Checking the history of these files, is_interpreted_frame_valid() has
> been written before the distinction between raw sp and unextended sp
> has been introduced in the frame class. Unfortunately, when
> unextended_sp was added, is_interpreted_frame_valid() has not been
> updated.
>
> Here's a new webrev where safe_for_sender computes both raw_sp and
> unextended_sp, and is_interpreted_frame_valid() checks the frame
> size using unextended_sp instead of raw sp.
>
> http://cr.openjdk.java.net/~fparain/8068655/webrev.01/
>
> I also added more comments.
>
> Note that I only modify one test in is_interpreted_frame_valid().
> Use of sp() or unextended_sp() could be discussed for each test,
> but in their current form they are wrong.
>
> Thanks,
>
> Fred
>
> On 26/01/2015 20:40, Dean Long wrote:
>> In sender_for_interpreter_frame(), we set the raw sender_sp but also
>> unextended_sp.  Should
>> safe_for_sender() be doing the same?
>>
>> dl
>>
>> On 1/26/2015 6:40 AM, Frederic Parain wrote:
>>> Greetings,
>>>
>>> Please review this small fix in the frame verification code.
>>> The bug report includes a detailed description of the issue.
>>>
>>> CR:
>>> https://bugs.openjdk.java.net/browse/JDK-8068655
>>>
>>> Webrev:
>>> http://cr.openjdk.java.net/~fparain/8068655/webrev.00/
>>>
>>> Thanks,
>>>
>>> Fred
>>>
>>
>