Messages in this thread | | | Date | Thu, 04 Sep 2014 13:54:09 +0100 | From | Michael Brown <> | Subject | Re: [REGRESSION] "efi: efistub: Convert into static library" and preparation patches |
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On 04/09/14 11:48, Maarten Lankhorst wrote: >>> If not, Ard please go ahead with option #2 above. Overkill yes, but I've >>> done the single __attribute__() hacks in other projects and someone >>> (usually me) always eventually forgets to tag some instance. >>> >> It appears we just got lucky on arm64, since we don't have any global >> variables, but the issue does exist there as well. >> > FWIW, visibility pushing doesn't seem to work for functions declared with extern. > Following seems to get rid of all GOTPCREL:
Are you sure? The iPXE build process relies on this:
/* Force visibility of all symbols to "hidden", i.e. inform gcc that * all symbol references resolve strictly within our final binary. * This avoids unnecessary PLT/GOT entries on x86_64. * * This is a stronger claim than specifying "-fvisibility=hidden", * since it also affects symbols marked with "extern". */ #ifndef ASSEMBLY #if __GNUC__ >= 4 #pragma GCC visibility push(hidden) #endif #endif /* ASSEMBLY */
and https://gcc.gnu.org/wiki/Visibility states that
"#pragma GCC visibility is stronger than -fvisibility; it affects extern declarations as well. -fvisibility only affects definitions, so that existing code can be recompiled with minimal changes. This is more true for C than C++; C++ interfaces tend use classes, which are affected by -fvisibility."
Michael
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