On 10/15/2015 12:37 PM, H.J. Lu wrote:
On Thu, Oct 15, 2015 at 1:44 AM, Richard Biener
<richard.guent...@gmail.com> wrote:
On Wed, Oct 14, 2015 at 6:21 PM, H.J. Lu <hongjiu...@intel.com> wrote:
By default, there is no visibility on builtin functions. When there is
explicitly declared visibility on the C library function which a builtin
function fall back on, we should honor the explicit visibility on the
the C library function.
Doesn't the C++ FE have the same issue?
Unlike gcc, visibility triggers a warning in g++:
memcpy.i:2:14: warning: ‘void* memcpy(void*, const void*, size_t)’:
visibility attribute ignored because it conflicts with previous
declaration [-Wattributes]
extern void *memcpy(void *dest, const void *src, size_t n)
^
<built-in>: note: previous declaration of ‘void* memcpy(void*, const
void*, size_t)’
[hjl@gnu-tools-1 pr67220]$
I see no good reason for C and C++ to have different behaviour here. It
looks like the C++ frontend sets DECL_VISIBILITY_SPECIFIED to 1 for
builtins, causing the above behaviour. Cc'ing Jason, but I think the C++
frontend should be changed not to set D_V_S and have the same changes as
the C frontend for merging the visibilities.
Other than that I don't see a problem with the concept. However, I also
agree that the tests should not be i386 specific.
One final question - it would seem that glibc is currently not affected
by this problem (at least I'm not seeing memcpy@plt calls in the binary
on my system), so how come this has become an issue now?
Bernd
