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Re: configuring out old ABI
On 2018-06-06 11:52, Jonathan Wakely wrote:
> On 06/06/18 10:45 +0200, Rasmus Villemoes wrote:
>> On 2018-06-06 10:30, Jonathan Wakely wrote:
>>> On 06/06/18 10:17 +0200, Rasmus Villemoes wrote:
>>>> Is there any chance of having a configuration combination completely
>>>> disabling the old ABI?
>>>
>>> Not currently, this is
>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65762
>>>
>>> If/when https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83077 gets
>>> implemented you could get it via
>>> --enable-symvers=gnu-versioned-namespace (but that also changes the
>>> ABI to be completely incompatible, instead of just dropping the
>>> non-cxx11 parts).
>>
>> Thanks for the quick reply. In my case, I only use the static libgcc and
>> libstdc++ (I'm targeting vxworks), and don't even know if I could build
>> a .so, so it seems that the logic in acinclude.m4 would complain loudly.
>> How would/does symvers affect libstdc++.a?
>
> When configured with --enable-symvers=gnu-versioned-namespace
> everything in the standard library is defined in a different
> namespace, so is completely ABI incompatible (even in a static
> library, which doesn't have versioned symbols).
Yes, but I was referring to this in acinclude.m4
if test $enable_symvers = gnu ||
test $enable_symvers = gnu-versioned-namespace ||
test $enable_symvers = sun; then
...
if test $glibcxx_shared_libgcc != yes; then
AC_MSG_WARN([=== You have requested GNU symbol versioning, but])
AC_MSG_WARN([=== you are not building a shared libgcc_s.])
AC_MSG_WARN([=== Symbol versioning will be disabled.])
enable_symvers=no
which would seem to prevent using
--enable-symvers=gnu-versioned-namespace when only static libraries are
built. But maybe that check could be removed if one is not building a
shared libstdc++?
Rasmus