Re: [gentoo-dev] [PATCH] multilib: allow specifying the subtype of library in get_libname

[Marty E. Plummer]

On Fri, Aug 03, 2018 at 09:13:35AM +0200, Fabian Groffen wrote:
> Just wondering, we have get_libname, get_modname, shouldn't we just
> introduce get_linklibname or something instead of trying to overload
> get_libname?
>
> The implementation of get_linklibname could be to just call get_libname
> for anything but mingw of course.
Actually that's a pretty good idea... Possibly with a warning to migrate
to the proper one in later eapis. Also, runtime libraries are a bit fun
too. for say, libFLAC(get_libname 8) on linux, you'd get libFLAC.so.8,
but on mingw-w64, you'd want libFLAC-8.dll on a mingw-w64 build.
>
> Fabian
>
> On 03-08-2018 00:09:41 -0500, Marty E. Plummer wrote:
> > Signed-off-by: Marty E. Plummer <hanetzer@×××××××××.com>
> > ---
> >
> > On mingw-w64 (and perhaps cygwin and mingw.org), there are two forms of
> > non-static libraries. Standard *.dll libraries are for runtime and are
> > loaded from %PATH% on windows systems, and are typically stored in
> > either /bin or /usr/bin on mingw-w64 cross-toolchain filesystems. Import
> > libraries, *.dll.a, are used when linking and live in the ''normal''
> > libdirs, eg, /lib, /usr/lib and so on.
> >
> > A number of ebuilds which otherwise work on mingw-w64 crossdev
> > toolchains exhibit failure due to usage of get_libname not being able to
> > specify which of the two types are required.
> >
> > For example, sys-libs/ncurses, uses the following snippet of code:
> > ln -sf libncurses$(get_libname) "${ED}"/usr/$(get_libdir)/libcurses$(get_libname) || die
> > in order to create a 'libcurses.so -> libncurses.so' symlink.
> >
> > However, on a crossdev-built mingw-w64 toolchain, one will end up with a
> > broken 'libcurses.dll -> libncurses.dll' symlink, which should properly
> > be a 'libcurses.dll.a -> libncurses.dll.a' symlink, as the symlink here
> > is provided to allow linking with -lcurses instead of -lncurses.
> >
> >  eclass/multilib.eclass | 52 ++++++++++++++++++++++++++++++++++++++----
> >  1 file changed, 48 insertions(+), 4 deletions(-)
> >
> > diff --git a/eclass/multilib.eclass b/eclass/multilib.eclass
> > index 350b6f949d1..6a99f5977ec 100644
> > --- a/eclass/multilib.eclass
> > +++ b/eclass/multilib.eclass
> > @@ -239,26 +239,70 @@ get_exeext() {
> >  }
> >
> >  # @FUNCTION: get_libname
> > -# @USAGE: [version]
> > +# @USAGE: --link|--run [version]
> >  # @DESCRIPTION:
> >  # Returns libname with proper suffix {.so,.dylib,.dll,etc} and optionally
> >  # supplied version for the current platform identified by CHOST.
> >  #
> > +# If '--link' argument is passed, the linktime library's suffix is returned,
> > +# as in the file that must exist to let `gcc -lfoo foo.c -o foo` to work.
> > +# If '--run' argument is passed, the runtime library's suffix is returned.
> > +#
> > +# In most unix-like platforms the two are identical, however on mingw-w64 the
> > +# linktime library has the suffix of '.dll.a' and the runtime library '.dll'.
> > +#
> >  # Example:
> >  #     get_libname ${PV}
> >  #     Returns: .so.${PV} (ELF) || .${PV}.dylib (MACH) || ...
> > +#     get_libname --link
> > +#     Returns: .so (ELF) || .dylib (MACH) || .dll.a (PE32) || ...
> >  get_libname() {
> > -	local libname
> > -	local ver=$1
> > +	local libtype="undefined"
> > +	local libname opt ver
> > +	for opt; do
> > +		case "${opt}" in
> > +			--link)
> > +				libtype="link"
> > +				shift
> > +				;;
> > +			--run)
> > +				libtype="run"
> > +				shift
> > +				;;
> > +			*)
> > +				;;
> > +		esac
> > +	done
> > +	ver="$1"
> > +	# general unixy types
> >  	case ${CHOST} in
> >  		*-cygwin*)       libname="dll.a";; # import lib
> > -		mingw*|*-mingw*) libname="dll";;
> >  		*-darwin*)       libname="dylib";;
> >  		*-mint*)         libname="irrelevant";;
> >  		hppa*-hpux*)     libname="sl";;
> >  		*)               libname="so";;
> >  	esac
> >
> > +	# wierd mingw-w64 stuff, maybe even cygwin
> > +	case ${CHOST} in
> > +		mingw*|*-mingw*)
> > +			case ${libtype} in
> > +				link)
> > +					libname="dll.a" # import library
> > +					;;
> > +				run)
> > +					libname="dll" # runtime library
> > +					;;
> > +				undefined)
> > +					eerror "please specify either --link or --run to get_libname"
> > +					eerror "for mingw builds, as there are two types of libraries"
> > +					eerror "on this platform"
> > +					die
> > +					;;
> > +			esac
> > +			;;
> > +	esac
> > +
> >  	if [[ -z $* ]] ; then
> >  		echo ".${libname}"
> >  	else
> > --
> > 2.18.0
> >
> >
>
> --
> Fabian Groffen
> Gentoo on a different level