CppunitTest_vcl_skia failing on tb68 with illegal instruction

[Luboš Luňák]

On Tuesday 09 of March 2021, Stephan Bergmann wrote:
> (e.g., <https://ci.libreoffice.org/job/gerrit_windows/90702/>).
>
> @Luboš:  I assume that external/skia (maybe since
> <https://git.libreoffice.org/core/+/ad8bff9d2625524999871ace65cfe0382f991f2
>4%5E!/> "update Skia to chrome/m90", which reached master on 2021-03-03?) is
> built with support for instruction set extensions that are not available on
> tb68.

 That doesn't make sense to me. The crashing test calls normal Skia code that 
shouldn't be special WRT instruction sets, and it's normally compiled with 
clang-cl without explicit instruction set flags. The only plausible 
explanation I can think of is that clang-cl defaults to a higher instruction 
set default than cl's (or ours) and the relevant code is somehow unlucky to 
have clang-cl to actually use such an instruction there. But even that 
doesn't really make sense, because that code should get called also by some 
of the previous tests. Moreover tb68 is reportedly E5530 CPU, which supports 
up to SSE4.2, so I don't quite see how something would get accidentally 
compiled to something not supported there without people noticing. Even on 
x86_64 clang doesn't default to anything higher than the baseline SSE2.

 Is it possible to debug the crash?

-- 
 Luboš Luňák
 l.lunak at collabora.com