Re: PROPOSAL: Extend inline asm syntax with size spec

Ingo Molnar
2018-10-08T05:58:46Z

* Segher Boessenkool <segher@kernel.crashing.org> wrote:

> > > More precise *size* estimates, yes. And if the user lies he should not
> > > be surprised to get assembler errors, etc.
> >
> > Yes.
> >
> > Another option would be if gcc parses the inline asm directly and
> > does a more precise size estimation. Which is a lot more involved and
> > complicated solution so I guess we wanna look at the simpler ones first.
> >
> > :-)
>
> Which is *impossible* to do. Inline assembler is free-form text.

"Impossible" is false: only under GCC's model and semantics of inline
asm that is, and only under the (false) assumption that the semantics
of the asm statement (which is a GCC extension to begin with) cannot
be changed like it has been changed multiple times in the past.

"Difficult", "not worth our while", perhaps.

Thanks,

Ingo