__attribute__((alias(foo))) and the hardening flags

Kevin Kofler kevin.kofler at chello.at
Fri Mar 13 01:09:59 UTC 2015

Jerry James wrote:
>                                          Since they contain identical
> symbols, the bundled polylmake version renames all of the symbols in
> the GMP-enabled version to have "_gmp" suffixes.  We did likewise, but
> to support applications that only want the GMP-enabled version and
> expect the original unaltered symbol names, we made declarations of
> the form "foo __attribute__((alias(foo_gmp)))" for each external
> symbol foo.
> And this in the .dynsym section:
>    109: 0000000000246100     0 OBJECT  GLOBAL DEFAULT   23 dd_purezero
>    634: 0000000000246100    32 OBJECT  GLOBAL DEFAULT   23 dd_purezero_gmp
> So dd_purezero is not, in fact, an undefined symbol.  It is an alias
> to dd_purezero_gmp, which is defined and has the proper relocation
> type.

Don't use __attribute__((alias(foo_gmp))), use asm("foo_gmp"), as per:

        Kevin Kofler

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