Am Donnerstag, 26. Februar 2015, 14:44:25 schrieb Emil Velikov: > Hi Marc > > On 17/02/15 09:40, Marc Dietrich wrote: > > This adds clang/gcc visibility macro detection to configure and > > util/macros.h. This is can be used to conveniently add e.g. a "HIDDEN" > > attribute to a function. > I believe this should be OK to go in regardless of the status of patch > 2. There are just a couple of trivial nitpicks.
as pointed out, not if there is a better solution. It would be nice if people
could test the alternative first.
> > Signed-off-by: Marc Dietrich <marvi...@gmx.de>
> > ---
> > v2: use VISIBILITY_*FLAGS instead of *FLAGS directly
> > v3: no change
> >
> > configure.ac | 28 ++++++----------------------
> > src/util/macros.h | 6 ++++++
> > 2 files changed, 12 insertions(+), 22 deletions(-)
> >
> > diff --git a/configure.ac b/configure.ac
> > index 351027b..266764a 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -189,6 +189,7 @@ AX_GCC_FUNC_ATTRIBUTE([flatten])
> >
> > AX_GCC_FUNC_ATTRIBUTE([format])
> > AX_GCC_FUNC_ATTRIBUTE([malloc])
> > AX_GCC_FUNC_ATTRIBUTE([packed])
> >
> > +AX_GCC_FUNC_ATTRIBUTE([visibility])
> >
> > AM_CONDITIONAL([GEN_ASM_OFFSETS], test "x$GEN_ASM_OFFSETS" = xyes)
> >
> > @@ -245,17 +246,13 @@ if test "x$GCC" = xyes; then
> >
> > AC_MSG_RESULT([yes]),
> > [CFLAGS="$save_CFLAGS -Wmissing-prototypes";
> >
> > AC_MSG_RESULT([no])]);
> >
> > + CFLAGS=$save_CFLAGS
>
> I'm not sure we want/need this one ?
it restores the CFLAGS from the test above. In fact I just moved it from the
blow upwards. Maybe the diff could be shorter.
>
> > # Enable -fvisibility=hidden if using a gcc that supports it
>
> As spotted by Sedat, please update the comment.
>
> > - 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${ax_cv_have_func_attribute_visibility}" = xyes; then
> > + VISIBILITY_CFLAGS="-fvisibility=hidden"
> > + VISIBILITY_CXXFLAGS="-fvisibility=hidden"
> > + fi
>
> As these two are no longer GCC "specific" we can move them out of the if
> test x$GCC = xyes, conditional.
right.
>
> > # Work around aliasing bugs - developers should comment this out
> > CFLAGS="$CFLAGS -fno-strict-aliasing"
> >
> > @@ -267,19 +264,6 @@ fi
> >
> > if test "x$GXX" = xyes; then
> >
> > CXXFLAGS="$CXXFLAGS -Wall"
> >
> > - # Enable -fvisibility=hidden if using a gcc that supports it
> > - save_CXXFLAGS="$CXXFLAGS"
> > - AC_MSG_CHECKING([whether $CXX supports -fvisibility=hidden])
> > - VISIBILITY_CXXFLAGS="-fvisibility=hidden"
> > - CXXFLAGS="$CXXFLAGS $VISIBILITY_CXXFLAGS"
> > - AC_LANG_PUSH([C++])
> > - AC_LINK_IFELSE([AC_LANG_PROGRAM()], AC_MSG_RESULT([yes]),
> > - [VISIBILITY_CXXFLAGS="" ; AC_MSG_RESULT([no])]);
> > - AC_LANG_POP([C++])
> > -
> > - # Restore CXXFLAGS; VISIBILITY_CXXFLAGS are added to it where needed.
> > - CXXFLAGS=$save_CXXFLAGS
> > -
> >
> > # Work around aliasing bugs - developers should comment this out
> > CXXFLAGS="$CXXFLAGS -fno-strict-aliasing"
> >
> > diff --git a/src/util/macros.h b/src/util/macros.h
> > index eec8b93..7682511 100644
> > --- a/src/util/macros.h
> > +++ b/src/util/macros.h
> > @@ -117,6 +117,12 @@ do { \
> >
> > #define PRINTFLIKE(f, a)
> > #endif
> >
> > +#ifdef HAVE_FUNC_ATTRIBUTE_VISIBILITY
> > +#define HIDDEN __attribute__((visibility("hidden")))
> > +#else
> > +#define HIDDEN
> > +#endif
> > +
>
> We already define HIDDEN in the asm code.
>
> Can you check (build or otherwise) that things don't clash for
> --enable-asm and --{en,dis}able-shared-glapi. Check the configure log,
> as we conveniently toggle the latter.
I always build with --enable-asm (or better without --disable-asm) and saw no
symbol clash. I guess because the required header is not included at the same
time. Is this possible at all (asm vs. c files)?
Another interesting point is in which case we can build without shared-glapi.
I failed to build ES1 or ES2 alone, because it seem to always require glapi.
This would mean that the dispatch table always begins with the glapi. Maybe I
confuse things, but in this case, just using
extern void shared_dispatch_stub_0();
would solve all problems without the HIDDEN hacks.
Marc
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