svn commit: r294530 - head/sys/sys

[Ed Maste]

On 21 January 2016 at 16:00, Renato Botelho <garga at freebsd.org> wrote:
>> On Jan 21, 2016, at 18:44, Ed Maste <emaste at freebsd.org> wrote:
>>
>> Author: emaste
>> Date: Thu Jan 21 20:44:21 2016
>> New Revision: 294530
>> URL: https://svnweb.freebsd.org/changeset/base/294530
>>
>> Log:
>>  Add STB_GNU_UNIQUE symbol binding definition
>>
>>  Red Hat created STB_GNU_UNIQUE to handle certain special cases relating
>>  to dynamically loading C++ DSOs[1].
>>
>>  We don't (currently) have support for STB_GNU_UNIQUE, but ought to
>>  reserve the value in ELFNN_ST_BIND. This will also be used by an
>>  upcoming ELF Tool Chain import.
>>
>>  [1] https://www.redhat.com/archives/posix-c++-wg/2009-August/msg00002.html
>>
>>  MFC after:   1 week
>>  Sponsored by:        The FreeBSD Foundation
>>
>> Modified:
>>  head/sys/sys/elf_common.h
>>
>> Modified: head/sys/sys/elf_common.h
>> ==============================================================================
>> --- head/sys/sys/elf_common.h Thu Jan 21 19:19:24 2016        (r294529)
>> +++ head/sys/sys/elf_common.h Thu Jan 21 20:44:21 2016        (r294530)
>> @@ -753,8 +753,9 @@ typedef struct {
>> #define       STB_LOCAL       0       /* Local symbol */
>> #define       STB_GLOBAL      1       /* Global symbol */
>> #define       STB_WEAK        2       /* like global - lower precedence */
>> -#define      STB_LOOS        10      /* Reserved range for operating system */
>> -#define      STB_HIOS        12      /*   specific semantics. */
>> +#define      STB_LOOS        10      /* Start of operating system reserved range. */
>> +#define      STB_GNU_UNIQUE  10      /* Unique symbol (GNU) */
>
> Looks like you meant to use 11 here, no?

No, it is supposed to be 10. STB_LOOS is a placeholder for the first
OS-specific entry, and STB_GNU_UNIQUE is the first one. It's similar
to STT_GNU_IFUNC (which we do use) -- it has the same value as
STT_LOOS.

These two are really more of a toolchain concern than a "GNU OS," but
either way STB_GNU_UNIQUE has the value 10, and if we end up
supporting this functionality we'll use the same value.