[PATCH] Gold: Treat symbols with version index 0 as unversioned

[Michael Matz]

Hello,

On Sat, 15 Nov 2025, H.J. Lu wrote:

> defines VER_NDX_LOCAL to 0 with a comment, "Symbol has local scope".  This
> leads to different interpretations by different linker implementations.
> However Solaris as well as ld and ld.so in glibc always treat symbols
> with version index 0 as unversioned symbols, defined or undefined, with
> global visibility.  As discussed in
> 
> https://sourceware.org/bugzilla/show_bug.cgi?id=33577
> 
> in hindsight, VER_NDX_NONE might be a better name.  Ali from Oracle is
> working on clarifying what version index 0 really means for unversioned
> symbols, defined or undefined, with global visibility.

Hmm?  I don't think that's what he's saying.  PR33577 was specifically 
about how NDX_LOCAL should be valid (and sensible) for _undefined_ 
symbols.  The only mentions of defined symbols related to the problems at 
hand was https://sourceware.org/bugzilla/show_bug.cgi?id=33577#c5:

...
    - Symbols that are not versioned are given version index 0. These can
      be either definitions, or external references.

    - The BASE version, which has index 1, is the version that holds the
      symbols defined by the object itself, that have not otherwise been 
      assigned to a different version, possibly with a linker script.
      By convention, the version is given the SONAME of the object. This
      is a VERDEF, so external references don't belong here.
...

So, sure, index 0 _can_ be used for defined symbols.  But I can't see how 
they then can used for resolving.  If they could, then there'd be an 
internal inconsistency in the above two items: symbols defined in an 
object (and that don't have a version otherwise), are to use index 1.  So, 
for index 0 to be used the symbol in question must be (a) unversioned and 
(b) not be defined (in the sense of being available to resolve against)
by the object (lest it had index 1).

So, no, I don't think you should resolve against defined symbols with 
NDX_LOCAL.  They have, as stated everywhere, local scope.


Ciao,
Michael.