On Fri, Jul 9, 2010 at 3:29 AM, Stefan Hajnoczi <stefa...@gmail.com> wrote:
> Richard Sandiford identified the issue: the compiler inlines
> pxe_menu_boot() because the symbol has visibility "hidden". From
> include/compiler.h:
>
> /* 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 */
>
> So although the function is extern, the pxe_menu_boot symbol has
> visibility "hidden" and the compiler decides inlining is okay, despite
> it being a weak symbol. Add __attribute__((visibility("default"))) to
> pxe_menu_boot() to test this.
>
> It seems to me that gcc interprets "hidden" as "all symbol references
> resolve strictly within the compilation unit" rather than "all symbols
> references resolve strictly within our final binary". Whether or not
> gcc changes its behavior, we need to solve this for gPXE so that it
> works on existing compilers.
Excellent job tracking this down. I wonder if
__attribute__((noinline)) would work as well?
-- Josh
> Stefan
> _______________________________________________
> gPXE-devel mailing list
> gPXE-devel@etherboot.org
> http://etherboot.org/mailman/listinfo/gpxe-devel
>
_______________________________________________
gPXE-devel mailing list
gPXE-devel@etherboot.org
http://etherboot.org/mailman/listinfo/gpxe-devel
