[Bug sanitizer/61771] Test failures in ASan testsuite on ARM Linux due to FP format mismatch between libasan and GCC.

["ramana at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61771

--- Comment #7 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
(In reply to Evgeniy Stepanov from comment #3)
> Yes, FP on ARM is non-standard and differs in GCC and Clang implementations.
> Disabling fast unwind is not really an option, as you are looking at 10x,
> maybe 100x slowdown (depending of the app, of course).
> It should be possible to detect fp layout on the frame basis - there is a
> slot (don't know which one off the top of my head) that is FP in one
> compiler and return address in the other. Comparing its contents with the
> current stack limits (readily available in ASan) should do the trick.
> 
> Of course, it would be awesome if we could synchronize (and document
> somewhere) FP stack layout between GCC and Clang - after all, there is no
> strong reason to do it one way or the other.

I think finding a fix in the run time will be better and probably more
resilient across versions of GCC. In any case I think this is worthy of a work
around in the sanitisers rather than in GCC itself. 

I don't know where the bugs for the sanitizer run time is tracked - so it maybe
worth closing this with a link to the appropriate upstream bug report.