Re: [binutils] libctf: Remove undefined functions from ver. map

[Nicholas Vinson <nvinson234@gmail.com>]

On 2/27/24 10:05, Nick Alcock wrote:
> On 27 Feb 2024, Sam James said:
> 
>> Nicholas Vinson <nvinson234@gmail.com> writes:
>>
>>> The functions ctf_label_set(), ctf_label_get(), ctf_arc_open(), ctf_fdopen(),
>>> ctf_open(), ctf_bfdopen(), and ctf_bfdopen_ctfsect() are not defined. Their
>>> inclusion in libctf/libctf.ver causes clang/llvm LTO optimizatiosn to fail with
>>> error messages similar to
> 
> This is definitely not right. They *are* defined, but only for some
> libraries built from this version script. You can't just take them out.
> 

Could you point me to the definitions for ctf_label_set() and 
ctf_label_get() ?

Using `git log -G` I found the declarations, but no definitions, in the 
following commits:

139633c307eb6f5746ea04f94a0b6382e51bccb9
0b11474080800192797236e30857a42818f5560d
87279e3cef5b2c54f4a01962cf9dcea38664a336
6dbf2b734063522b4f3d7403ce7a2b436802b839

I do find definitions for the other so the other symbols, so I'll find a 
different way to handle those symbols in the version file.

>>> Fixes Gentoo bug 914640 (https://bugs.gentoo.org/914640)
>>>
>>> Signed-off-by: Nicholas Vinson <nvinson234@gmail.com>
>>> ---
>>>   libctf/libctf.ver | 8 --------
>>>   1 file changed, 8 deletions(-)
>>
>> [CCing a possible reviewer.]
>>
>>>
>>> diff --git a/libctf/libctf.ver b/libctf/libctf.ver
>>> index 0ff825d033b..08e1b27341f 100644
>>> --- a/libctf/libctf.ver
>>> +++ b/libctf/libctf.ver
>>> @@ -80,9 +80,6 @@ LIBCTF_1.0 {
>>>   	ctf_enum_name;
>>>   	ctf_enum_value;
>>>   
>>> -	ctf_label_set;
>>> -	ctf_label_get;
>>> -
>>>   	ctf_label_topmost;
>>>   	ctf_label_info;
>>
>> Can you explain each of these? Were they ever in binutils/libctf
>> (possible typos) or did they get removed?
> 
> The ctf_label things are historical artifacts from the Solaris days used
> by their old stabs-based deduplicator. Some of the code remains, and I
> have hopes of repurposing much of it and the unused CTF file format
> section for a better way of encoding child dicts with conflicting types
> in them in the future, but ctf_label_{set,get} appear to have been
> nonexistent for as long as I've had anything to do with libctf. They
> should be removed from ctf-api.h too.
> 
>>>   
>>> @@ -139,7 +136,6 @@ LIBCTF_1.0 {
>>>   
>>>   	ctf_arc_write;
>>>   	ctf_arc_write_fd;
>>> -	ctf_arc_open;
>>>   	ctf_arc_bufopen;
>>>   	ctf_arc_close;
>>>   	ctf_arc_open_by_name;
>>> @@ -165,10 +161,6 @@ LIBCTF_1.0 {
>>>   	ctf_link_shuffle_syms;
>>>   	ctf_link_write;
>>>   
>>> -	ctf_fdopen;                             /* libctf only.  */
>>> -	ctf_open;                               /* libctf only.  */
>>> -	ctf_bfdopen;                            /* libctf only.  */
>>> -	ctf_bfdopen_ctfsect;                    /* libctf only.  */
>>>       local:
>>>   	*;
>>>   };
> 
> These are definitely used, and exist -- as the comments note, some of
> them exist only in libctf.so, not in libctf-nobfd.so.
> 
> lld is not the first linker to complain about missing symbols: recent
> Solaris linkers do as well, so we arranged to mark such symbols as
> /* libctf only. */ so that they can be removed from the version script
> used to link ctf-nobfd.so (see libctf/configure.ac for the code that
> does that). But here too we have a bug: ctf_arc_open is in
> ctf-open-bfd.c, thus is not found in libctf-nobfd.so: it should be at
> the end of the version script like all other such symbols and marked as
> /* libctf only. */ as well.
> 

I'll take a look.

Thanks,
Nicholas Vinson