Actually, never mind, it's working fine: https://gist.github.com/wheybags/b7e4152daf76c72503e9e1f52f3dca3d and I have some other problem.
On Fri, Jan 26, 2018 at 9:22 PM, H.J. Lu <hjl.to...@gmail.com> wrote: > On Fri, Jan 26, 2018 at 1:17 PM, Tom Mason <wheyb...@wheybags.com> wrote: > > I'm not entirely sure I understand that issue. From what I understand, > calls > > to a function in a shared library should always use the PLT? > > Also, I don't understand the purpose of applying hidden visibility to an > > extern symbol, > > There is no need for PLT since hidden symbol is defined locally. But > GCC ignores hidden visibility for libcalls, like memcpy. If GCC treats > them like normal calls, your scheme and my testcase should work. > > > > But anyway, doesn't matter terribly much if I understand :p > > > > On Fri, Jan 26, 2018 at 8:37 PM, H.J. Lu <hjl.to...@gmail.com> wrote: > >> > >> On Fri, Jan 26, 2018 at 12:29 PM, Tom Mason <wheyb...@wheybags.com> > wrote: > >> > Hi, > >> > I've got a project here: > >> > https://github.com/wheybags/glibc_version_header > >> > which uses .symver directives to link to a specified version of glibc, > >> > so > >> > long as it's older than the version on your system. > >> > This works, but a problem I'm having is that gcc itself will sometimes > >> > insert calls to memcpy (or memmove, memset and memcmp), as documented > >> > here: > >> > https://gcc.gnu.org/onlinedocs/gcc/Standards.html > >> > When it does so, it doesn't respect the .symver directives, and uses > the > >> > default version. > >> > Is there any way for me to force the version for these symbols aswell? > >> > I'm aware that I can disable the whole mechanism with -freestanding, > but > >> > I > >> > don't want to cripple the optimiser. > >> > >> I think this is related to: > >> > >> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67220 > >> > >> -- > >> H.J. > > > > > > > > -- > H.J. >
