On 2019-12-18 14:19 +0100, Jan Hubicka wrote:
> The problem here is that we lie to the compiler (by pretending that
> foo_v2 is exported from DSO while it is not) and force user to do the
> same.
>
> We support two ways to hide symbol - either at compile time via
> attribute((visibility("hidden"))) or at link-time via map file. The
> first produces better code because compiler can do more optimizations
> knowing that the symbol can not be interposed.
I just get your point: if the library calls foo_v2 it won't be interposed. If
it supposes a call to be interposed it should call foo() [foo@@VER_2] instead of
foo_v2().
But it seems there is no way we can do this [even with traditional
__asm__("symver foo, foo@@VER_2")]. For this purpose we should either:
1. Change GAS (introducing some new syntax like '@@@@' or '.symver_export')
or
2. Add some mangled symbol name in GCC (like ".LSYMVERx" or
"foo_v2.symver_export").
--
Xi Ruoyao <xry...@mengyan1223.wang>
School of Aerospace Science and Technology, Xidian University
