[fpc-devel] Optimization breaks check for overridden function / Is there a better way to check?

[Sven Barth]

Am 17.10.2025 um 19:54 schrieb Pierre Muller via fpc-devel:
> Hi David,
>
> this looks very similar to a problem that we are trying to
> debug for a while, and that I recently submitted as a bug report:
>
> https://gitlab.com/freepascal.org/fpc/source/-/issues/41439
>
> The problem has been nicely simplified by alligator in
>
> https://gitlab.com/freepascal.org/fpc/source/-/issues/41444
>
> There is some problem related to PPU writing...
>
>   I hope to be able using this simplified example t understand better 
> this issue,
> but I am currently still busy with the previous issue, also raised by 
> alligator:
>
> https://gitlab.com/freepascal.org/fpc/source/-/issues/41443
>
> for which I hope to have found a fix.

David's problem is *not* due to a corruction or a bug, but due to an 
optimization that FPC performs that leads to different behavior, namely 
changing virtual methods that are empty to EmptyMethod to reduce the 
number of duplicate (empty) methods in the binary.

Regards,
Sven