Hi Wilco, Thanks for your feedback.
> On 8 Feb 2019, at 22:35, Wilco Dijkstra <wilco.dijks...@arm.com> wrote: > > Hi Olivier, > >> Sorry, I had -mapcs-frame in mind. > > That's identical to -mapcs, and equally deprecated. It was superceded 2 > decades > ago. -mpcs-frame bugs have been reported multiple times, including on VxWorks. > For example https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64379 suggests > VxWorks doesn't need -mapcs-frame. And that was in 2014! > So I think we need to push much harder on getting rid of obsolete stuff and > avoid people encountering these nasty issues. People are strongly encouraged to move to VxWorks7 (bpabi) these days and we'll probably reinforce that message. VxWorks6 is however still around and the environment (toolchain, libraries, ...) is abi=apcs-gnu + apcs-frame, so right now we unfortunately don't have much of a choice, and it was not working that bad until gcc-7 in our experience. I performed a round of testing with an aapcs compiler, out of curiosity to double check, and the incompatibilities are indeed visible. On calls to printf with a "double" as the first va-argument, for example, where the argument is passed through r2 & r3 but expected in r1 & r2 by the target library. apcs-frame apart, it looks like stack-checking could be affected as well. I need to think about this some more. Olivier
