[FFmpeg-devel] [PATCH] configure: reserve a register for gcc before 5 on x86_32 with PIE

Carl Eugen Hoyos ceffmpeg at gmail.com
Sun Nov 20 14:38:02 EET 2016

2016-11-20 1:07 GMT+01:00 Andreas Cadhalpun <andreas.cadhalpun at googlemail.com>:
> gcc before gcc-5 reserves a register on x86_32 for the GOT, when PIE is
> enabled.
> This fixes build failures due to:
> error: 'asm' operand has impossible constraints

Not reproducible with vanilla gcc 4.9.1 and gcc 4.4.6 so the patch is
not ok as-is afaict.

The tested (32bit) configure line here was:
 --enable-gpl --toolchain=hardened --disable-stripping --enable-shared

> A build log of a failed build with gcc 4.9 is available at:
> https://buildd.debian.org/status/fetch.php?pkg=ffmpeg&arch=i386&ver=7%3A3.2-2~bpo8%2B1&stamp=1478791165

Please consider to remove the following options from the configure line,
they do lead to more user questions and make support more difficult:

Is --disable-stripping really useful? Doesn't it only add symbols to
files that cannot be read by gdb?
(Sorry if I misremember)

Carl Eugen

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