Re: ASM 5.2 ?

Hi Rob,

"ClassWriter.getCommonSuperClass" is needed for computation of stack map
frames, i.e. when you specify ClassWriter.COMPUTE_FRAMES as flag for
ClassWriter.
If you don't request this computation explicitly, carefully track them and
perform updates for them as we do in JaCoCo, then the only case to trigger
call of this method - is to trigger resizing in ASM by a big method as
described in https://github.com/jacoco/jacoco/pull/177
After fix for ASM #317630 , resizing won't cause this - that's what we see
in JaCoCo tests.
So "getCommonSuperClass" is still here, but only for the case when you
explicitly request computation of stack map frames with flag mentioned
above. And I doubt that there is a way to get rid of it in such case or to
implement it without having actual classes. You right - access to classes
is problematic, especially in OSGi environment, and that's why in JaCoCo we
track and modify stack map frames by ourselves.
That's my understanding, but maybe ASM developers can confirm.

Hope this helps.

Evgeny

On Mon, Dec 12, 2016 at 12:04 AM Rob Bygrave <[email protected]>
wrote:

> Hi,
>
> Apologies if this is slightly off topic.
>
> *> jacoco/issues/177 <https://github.com/jacoco/jacoco/issues/177>*
>
> With this issue I see the mention of
> ClassWriter.getCommonSuperClass(Unknown Source) ... and the issue of ASM
> needing to load classes to re-calculate the stack frames. As an ASM user
> (for Ebean ORM) I hit this issue a lot and we try to ensure the agent has
> access to the appropriate classpath such that it can load classes for
> ClassWriter.getCommonSuperClass().
>
> Sometimes depending on the context (more specifically enhancement running
> as an IDE plugin for IDEA and Eclipse etc) it is hard to build and supply
> this classpath for the agent/enhancement.
>
> Is there a plan to remove this classpath requirement (ie. change the
> implementation of ClassWriter.getCommonSuperClass() such that it doesn't
> need the actual Classes) ?
>
> If there was that would be very welcome indeed and yes I'd love to see a
> 5.2 release with that change.
>
> Apologies if I have completely missed the topic here.
>
>
> Cheers, Rob.
>


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