Re: [PULL 00/10] Bitmaps patches

[Eric Blake]

On 3/17/20 9:00 AM, Peter Maydell wrote:
> On Tue, 17 Mar 2020 at 04:38, John Snow <address@hidden> wrote:

> >    block/qcow2-bitmap: use bdrv_dirty_bitmap_next_dirty (2020-03-12 16:36:46 
> > -0400)
> >
> > ----------------------------------------------------------------
> > Pull request
> >
> > ---------------------------------------------------------------
>
> Hi; this fails to compile with clang:
>
> /home/petmay01/linaro/qemu-for-merges/nbd/server.c:1937:1: error:
> unused function 'glib_listautoptr_cleanup_NBDExtentArray'
> [-Werror,-Wunused-function]
> G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free);
> ^
> /usr/include/glib-2.0/glib/gmacros.h:462:22: note: expanded from macro
> 'G_DEFINE_AUTOPTR_CLEANUP_FUNC'
>    static inline void _GLIB_AUTOPTR_LIST_FUNC_NAME(TypeName) (GList
> **_l) { g_list_free_full (*_l, (GDestroyNotify) func); } \
>                       ^
> /usr/include/glib-2.0/glib/gmacros.h:443:48: note: expanded from macro
> '_GLIB_AUTOPTR_LIST_FUNC_NAME'
> #define _GLIB_AUTOPTR_LIST_FUNC_NAME(TypeName)
> glib_listautoptr_cleanup_##TypeName
>                                                 ^
> <scratch space>:49:1: note: expanded from here
> glib_listautoptr_cleanup_NBDExtentArray
> ^

Should we add -Wno-unused-function to CFLAGS when dealing with a version 
of clang that complains about that version of glib's headers?  Is it 
fixed in a newer version of glib, where we could just backport a newer 
definition of G_DEFINE_AUTOPTR_CLEANUP_FUNC() that adds whatever 
annotations are needed to shut the compiler up?

On IRC, danpb pointed me to libvirt's solution:
https://libvirt.org/git/?p=libvirt.git;a=commit;h=44e7f029

Maybe we just write our own macro wrapper around 
G_DEFINE_AUTOPTR_CLEANUP_FUNC which takes care of adding necessary 
annotations and use that instead (and our macro name might be shorter...)

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org