[PATCH libdrm] configure: Support symbol visibility when available

[Rob Clark]

On Wed, Jul 30, 2014 at 10:37 AM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> On 30/07/14 15:31, Rob Clark wrote:
>> On Wed, Jul 30, 2014 at 9:48 AM, Thierry Reding
>> <thierry.reding at gmail.com> wrote:
>>> From: Thierry Reding <treding at nvidia.com>
>>>
>>> Checks whether or not the compiler supports the -fvisibility option. If
>>> so it sets the VISIBILITY_CFLAGS variable which can be added to the per
>>> directory AM_CFLAGS where appropriate.
>>>
>>> By default all symbols will be hidden via the VISIBILITY_CFLAGS. The
>>> drm_public macro can be used to mark symbols that should be exported.
>>
>> hmm, maybe dumb question, I might possibly have missed some discussion
>> on this, but if we merged this without a heap of patches to export
>> libdrm and libdrm_foo syms, wouldn't everything be hidden?
>>
>> Maybe we should introduce drm_public first.. then once stuff is
>> converted to use it actually start hiding things?
>>
> This adds the tool, but it's up-to the individual libraries/makefiles to make
> use of it.
>
> All you need is:
>  - append $(VISIBILITY_CFLAGS) to libdrm_freedreno_CFLAGS
>  - prefix each exported function definition with DRM_PUBLIC
>  - ***
>  - profit :P

ahh, ok, that makes much more sense.. thx :-)

BR,
-R


> -Emil
>
>>
>> BR,
>> -R
>>
>>> Signed-off-by: Thierry Reding <treding at nvidia.com>
>>> ---
>>> Changes in v3:
>>> - distribute libdrm.h
>>>
>>>  Makefile.am  |  1 +
>>>  configure.ac | 20 ++++++++++++++++++++
>>>  libdrm.h     | 34 ++++++++++++++++++++++++++++++++++
>>>  3 files changed, 55 insertions(+)
>>>  create mode 100644 libdrm.h
>>>
>>> diff --git a/Makefile.am b/Makefile.am
>>> index 826c30d0c0d9..65680da963eb 100644
>>> --- a/Makefile.am
>>> +++ b/Makefile.am
>>> @@ -69,6 +69,7 @@ libdrm_la_SOURCES =                           \
>>>         xf86drmSL.c                             \
>>>         xf86drmMode.c                           \
>>>         xf86atomic.h                            \
>>> +       libdrm.h                                \
>>>         libdrm_lists.h
>>>
>>>  libdrmincludedir = ${includedir}
>>> diff --git a/configure.ac b/configure.ac
>>> index 1c78c4520c49..f7c7177bfb2a 100644
>>> --- a/configure.ac
>>> +++ b/configure.ac
>>> @@ -366,6 +366,26 @@ AC_ARG_WITH([kernel-source],
>>>             [kernel_source="$with_kernel_source"])
>>>  AC_SUBST(kernel_source)
>>>
>>> +dnl Add flags for gcc and g++
>>> +if test "x$GCC" = xyes; then
>>> +    # Enable -fvisibility=hidden if using a gcc that supports it
>>> +    save_CFLAGS="$CFLAGS"
>>> +    AC_MSG_CHECKING([whether $CC supports -fvisibility=hidden])
>>> +    VISIBILITY_CFLAGS="-fvisibility=hidden"
>>> +    CFLAGS="$CFLAGS $VISIBILITY_CFLAGS"
>>> +    AC_LINK_IFELSE([AC_LANG_PROGRAM()], AC_MSG_RESULT([yes]),
>>> +                   [VISIBILITY_CFLAGS=""; AC_MSG_RESULT([no])]);
>>> +
>>> +    # Restore CFLAGS; VISIBILITY_CFLAGS are added to it where needed.
>>> +    CFLAGS=$save_CFLAGS
>>> +
>>> +    if test "x$VISIBILITY_CFLAGS" != x; then
>>> +        AC_DEFINE(HAVE_VISIBILITY, 1, [Compiler has -fvisibility support])
>>> +    fi
>>> +
>>> +    AC_SUBST([VISIBILITY_CFLAGS])
>>> +fi
>>> +
>>>  AC_SUBST(WARN_CFLAGS)
>>>  AC_CONFIG_FILES([
>>>         Makefile
>>> diff --git a/libdrm.h b/libdrm.h
>>> new file mode 100644
>>> index 000000000000..23926e6f6741
>>> --- /dev/null
>>> +++ b/libdrm.h
>>> @@ -0,0 +1,34 @@
>>> +/*
>>> + * Copyright © 2014 NVIDIA Corporation
>>> + *
>>> + * Permission is hereby granted, free of charge, to any person obtaining a
>>> + * copy of this software and associated documentation files (the "Software"),
>>> + * to deal in the Software without restriction, including without limitation
>>> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>>> + * and/or sell copies of the Software, and to permit persons to whom the
>>> + * Software is furnished to do so, subject to the following conditions:
>>> + *
>>> + * The above copyright notice and this permission notice shall be included in
>>> + * all copies or substantial portions of the Software.
>>> + *
>>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>>> + * OTHER DEALINGS IN THE SOFTWARE.
>>> + */
>>> +
>>> +#ifndef LIBDRM_LIBDRM_H
>>> +#define LIBDRM_LIBDRM_H
>>> +
>>> +#if defined(HAVE_VISIBILITY)
>>> +#  define drm_private __attribute__((visibility("hidden")))
>>> +#  define drm_public __attribute__((visibility("default")))
>>> +#else
>>> +#  define drm_private
>>> +#  define drm_public
>>> +#endif
>>> +
>>> +#endif
>>> --
>>> 2.0.3
>>>
>>> _______________________________________________
>>> dri-devel mailing list
>>> dri-devel at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>