Re: [PATCH v2] x86: mostly disable '-maccumulate-outgoing-args'

[Josh Poimboeuf]

On Wed, Mar 22, 2017 at 08:51:53AM +0100, Ingo Molnar wrote:
> > +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) && \
> > +	!defined(CC_USING_FENTRY) && \
> > +	!defined(CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE)
> > +# error Your compiler does not support function graph tracing
> > +#endif
> 
> Might make sense to add the compiler option that is missing, i.e. something like:
> 
>   # error Your compiler does not support function graph tracing (-mfentry)
> 
> (or whatever compiler feature is missing.)

I left it vague because otherwise it would need a paragraph :-)

After Steven's latest patches which port fentry to x86-32, I think the
precise version would be:

  # error The following combination is not supported: ((compiler missing -mfentry) || (CONFIG_X86_32 and !CONFIG_DYNAMIC_FTRACE)) && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE.

-- 
Josh