Re: [musl] Release prep for 1.2.1, and afterwards

[Rich Felker <dalias@libc.org>]

On Tue, Jul 07, 2020 at 05:00:20PM +0200, Szabolcs Nagy wrote:
> * Rich Felker <dalias@libc.org> [2020-07-06 18:12:43 -0400]:
> > I think you saw already, but just to make it clear on the list too,
> > it's upstream now. I'm open to further improvements like doing
> > memmove (either as a separate copy of the full implementation or some
> > minimal branch-to-__memcpy_fwd approach) but I think what's already
> > there is sufficient to solve the main practical performance issues
> > users were hitting that made aarch64 look bad in relation to x86_64.
> > 
> > I'd still like to revisit the topic of minimizing the per-arch code
> > needed for this so that all archs can benefit from the basic logic,
> > too.
> 
> thanks.
> 
> note that the code has some internal .p2align
> directives that assume the entry is aligned to
> some large alignment (.p2align 6 in orig code)
> 
> i think it would be better to keep the entry
> aligned (but i don't know if it makes a big
> difference on some existing core, it's more
> for consistency with upstream).
> 
> musl normally does not align function entries
> but for a few select functions it is probably
> not too much overhead?

I was under the impression that any .p2align N in the section
inherently aligns the whole section as if it started with .p2align N,
in which case not writing it explicitly just avoids redundancy and
makes sure you don't actually have an initial alignment that's larger
than any alignment actually wanted later. Is this incorrect?

(To be incorrect I think it would have to do some fancy
elastic-section-contents hack, but maybe aarch64 ELF object ABI has
that..?)

Rich