From: "Michał Górny" <mgorny@gentoo.org>
To: gentoo-dev@lists.gentoo.org
Cc: aballier@gentoo.org
Subject: Re: [gentoo-dev] [PATCH 2/2] Support wrapping headers for multilib ABIs.
Date: Sun, 24 Mar 2013 16:41:15 +0100 [thread overview]
Message-ID: <20130324164115.1af3b499@pomiocik.lan> (raw)
In-Reply-To: <20130324161452.63a55140@portable>
[-- Attachment #1: Type: text/plain, Size: 6018 bytes --]
On Sun, 24 Mar 2013 16:14:52 +0100
Alexis Ballier <aballier@gentoo.org> wrote:
> On Sat, 23 Mar 2013 17:26:38 +0100
> Michał Górny <mgorny@gentoo.org> wrote:
>
> > ---
> > gx86/eclass/autotools-multilib.eclass | 82
> > +++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+)
> >
> > diff --git a/gx86/eclass/autotools-multilib.eclass
> > b/gx86/eclass/autotools-multilib.eclass index d7372b0..c65c777 100644
> > --- a/gx86/eclass/autotools-multilib.eclass
> > +++ b/gx86/eclass/autotools-multilib.eclass
>
>
> why not multilib-build ?
Because it has two parts which have to be called at the right time.
It doesn't have a public API yet, so I'm putting it where I can test it
sanely.
> > @@ -33,6 +33,28 @@ inherit autotools-utils multilib-build
> >
> > EXPORT_FUNCTIONS src_prepare src_configure src_compile src_test
> > src_install
> > +# @ECLASS-VARIABLE: MULTILIB_WRAPPED_HEADERS
> > +# @DESCRIPTION:
> > +# A list of headers to wrap for multilib support. The listed headers
> > +# will be moved to a non-standard location and replace with a file
> > +# including them conditionally to current ABI.
> > +#
> > +# This variable has to be a bash array. Paths shall be relative to
> > +# installation root (${D}), and name regular files. Recursive
> > wrapping +# is not supported.
> > +#
> > +# Please note that header wrapping is *discouraged*. It is preferred
> > to +# install all headers in a subdirectory of libdir and use
> > pkg-config to +# locate the headers. Some C preprocessors will not
> > work with wrapped +# headers.
> > +#
> > +# Example:
> > +# @CODE
> > +# MULTILIB_WRAPPED_HEADERS=(
> > +# /usr/include/foobar/config.h
> > +# )
> > +# @CODE
> > +
> > autotools-multilib_src_prepare() {
> > autotools-utils_src_prepare "${@}"
> > }
> > @@ -49,13 +71,73 @@ autotools-multilib_src_test() {
> > multilib_foreach_abi autotools-utils_src_test "${@}"
> > }
> >
> > +_autotools-multilib_wrap_headers() {
> > + debug-print-function ${FUNCNAME} "$@"
> > + local f
> > +
> > + for f in "${MULTILIB_WRAPPED_HEADERS[@]}"; do
> > + # drop leading slash if it's there
> > + f=${f#/}
> > +
> > + if [[ ${f} != usr/include/* ]]; then
> > + die "Wrapping headers outside
> > of /usr/include is not supported at the moment."
> > + fi
>
> Do you really want to support this at some point? Why?
Honestly? No. But if people need it, I don't see much of a problem to
add the support in the future.
> I'd just go for paths relative to $EPREFIX/usr/include (or
> $ED/usr/include) for MULTILIB_WRAPPED_HEADERS. That would simplify the
> code.
That's true. But on the other hand, that would introduce yet another
root for paths which would probably end up being confusing.
Using /usr/include/... feels more natural IMO.
And of course, it leaves the possibility of supporting other locations
in the future.
> > + # and then usr/include
> > + f=${f#usr/include/}
> > +
> > + local dir=${f%/*}
> > +
> > + # $CHOST shall be set by multilib_toolchain_setup
> > + dodir "/tmp/multilib-include/${CHOST}/${dir}"
> > + mv "${ED}/usr/include/${f}"
> > "${ED}/tmp/multilib-include/${CHOST}/${dir}/" || die +
>
> why not use $T rather than $ED/tmp ?
I prefer using $D rather than $T for files which are intended to be
installed. Purely theoretically, $T could be on another filesystem than
$D. Then, moving the file back and forth could cause it to lose some
of the metadata -- and will be slower, of course.
> > + if [[ ! -f ${ED}/tmp/multilib-include/${f} ]]; then
> > + dodir "/tmp/multilib-include/${dir}"
> > + cat > "${ED}/tmp/multilib-include/${f}"
> > <<_EOF_ || die +/* This file is auto-generated by
> > autotools-multilib.eclass
> > + * as a multilib-friendly wrapper to /${f}. For the original content,
> > + * please see the files that are #included below.
> > + */
> > +_EOF_
> > + fi
> > +
> > + local defs
> > + case "${ABI}" in
>
> didn't you say $ABI may have name collisions?
> considering the code below, it seems much safer to match on $CHOST
Yes, that's why I've put the whole matching inline instead of
introducing a function to obtain the values. The current design
of the eclass -- which was quite stupid of me -- doesn't provide
a way to access that ABI_* thing. I am going to change that
in the future but don't want to step into two different issues
at a time.
At a first glance, $CHOST sounds like a neat idea. But I'm afraid it's
not a really safe choice. From a quick glance, CHOST values for x86
were:
i*86-pc-linux-gnu
x86_64-pc-linux-gnu
x86_64-pc-linux-gnux32
I feel like there's a lot of variables here, ends up in a bit ugly
pattern matching IMO.
> [...]
>
> It'd be nice to have an attempt to support all the ABIs gentoo supports
> in that file: I'd prefer to spot possible problems with this solution
> vs. sedding a template for example to be seen before having to rewrite
> it.
> For example, IIRC, ppc64 defines both __powerpc__ and __powerpc64__,
> the natural way would be:
> #if defined(__powerpc64__)
> ppc64 stuff
> #elif defined(__powerpc__)
> ppc stuff
> #endif
>
> with your approach that'd be:
> #if defined(__powerpc__) && !defined(__powerpc64__)
> ppc stuff
> #elif defined(__powerpc64__)
> ppc64 stuff
> #endif
I had the same problem with x32. I've chosen the solution which worked
and was easy to implement.
> doing with a template has its disadvantages but allows more flexibility
> in how the #ifery is written; I don't want to realize your approach
> cannot deal with some weird arches after it has been deployed.
To be honest, I can't really imagine how we could work with a template
here. It would at least require the function to be aware of other ABIs
which I really wanted to avoid. Of course, then there's the whole code
to handle it, and honestly I don't have a vision how it would work.
--
Best regards,
Michał Górny
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 966 bytes --]
next prev parent reply other threads:[~2013-03-24 15:40 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-23 16:25 [gentoo-dev] [PATCHES] Header wrapping support for multilib Michał Górny
2013-03-23 16:26 ` [gentoo-dev] [PATCH 1/2] Introduce multibuild_merge_root() to merge interim installs Michał Górny
2013-03-23 17:00 ` Ulrich Mueller
2013-03-23 17:28 ` Michał Górny
2013-03-24 7:47 ` Ulrich Mueller
2013-03-24 10:09 ` Michał Górny
2013-03-24 13:40 ` Ulrich Mueller
2013-03-24 14:13 ` Michał Górny
2013-03-24 20:18 ` Zac Medico
2013-03-25 22:42 ` [gentoo-dev] [PATCH] " Michał Górny
2013-03-23 17:44 ` [gentoo-dev] [PATCH 1/2] " Alec Warner
2013-03-23 18:57 ` Michał Górny
2013-03-23 18:57 ` [gentoo-dev] " Jonathan Callen
2013-03-23 19:02 ` Alec Warner
2013-03-23 16:26 ` [gentoo-dev] [PATCH 2/2] Support wrapping headers for multilib ABIs Michał Górny
2013-03-24 15:14 ` Alexis Ballier
2013-03-24 15:41 ` Michał Górny [this message]
2013-03-24 20:01 ` Alexis Ballier
2013-03-25 22:22 ` [gentoo-dev] [PATCH] " Michał Górny
2013-03-23 16:46 ` [gentoo-dev] [PATCHES] Header wrapping support for multilib Diego Elio Pettenò
2013-03-23 17:32 ` Michał Górny
2013-03-23 17:32 ` Diego Elio Pettenò
2013-03-23 19:56 ` [gentoo-dev] [PATCH] Support wrapping headers for multilib ABIs Michał Górny
2013-03-23 20:03 ` Michał Górny
2013-03-23 22:01 ` [gentoo-dev] " Jonathan Callen
2013-04-01 9:19 ` [gentoo-dev] [PATCHES] Header wrapping support for multilib Michał Górny
2013-04-02 10:59 ` Alexis Ballier
2013-04-02 11:47 ` Michał Górny
2013-04-04 8:07 ` Alexis Ballier
2013-04-04 17:53 ` Michał Górny
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130324164115.1af3b499@pomiocik.lan \
--to=mgorny@gentoo.org \
--cc=aballier@gentoo.org \
--cc=gentoo-dev@lists.gentoo.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox