1601590 - Can't use --enable-warnings-as-errors on Fedora 30

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[Simon Giesecke [:sg] [he/him]]

When I try to use a mozconfig with

ac_add_options --enable-optimize="-Og"
ac_add_options --enable-warnings-as-errors

I get an error:

 0:01.76 /usr/include/features.h:382:4: error: _FORTIFY_SOURCE requires compiling with optimization (-O) [-Werror,-W#warnings]

Maybe it is possible to let --enable-warnings-as-errors set _FORTIFY_SOURCE only if --enable-optimize has a compatible settings?

Comment 1

[Chris Manchester (limited bugmail, email directly)]

I wasn't able to re-produce this on my machine, can you provide more info about your clang/sysroot or other mozconfig options you might have?

Comment 2

[Simon Giesecke [:sg] [he/him]]

I tried various variants, and I now found that with this mozconfig (nothing else in there):

ac_add_options --enable-optimize="-O2"                                          
ac_add_options --enable-linker=lld                                              
ac_add_options --enable-warnings-as-errors 

doesn't work either, with the same error:

 0:35.28 In file included from /home/simon/work/refactor/memory/replace/dmd/test/SmokeDMD.cpp:16:
 0:35.28 In file included from /home/simon/work/refactor/obj-x86_64-pc-linux-gnu/dist/system_wrappers/errno.h:3:
 0:35.28 In file included from /usr/include/errno.h:25:
 0:35.28 In file included from /home/simon/work/refactor/obj-x86_64-pc-linux-gnu/dist/system_wrappers/features.h:3:
 0:35.28 /usr/include/features.h:382:4: error: _FORTIFY_SOURCE requires compiling with optimization (-O) [-Werror,-W#warnings]
 0:35.28 #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
 0:35.28    ^

I am on Fedora 30, the clang is the one from .mozbuild, currently clang version 9.0.0. /usr/include/features.h is from glibc-headers-2.29-27.fc30.

Comment 3

[Mike Hommey [:glandium]]

SmokeDMD.cpp is force-built with -O0 per memory/replace/dmd/test/moz.build. The check in features.h is kind of controversial, actually, as it has caused multiple problems. You found one more. It was removed in Debian, but stays in Fedora. I guess we could work around with #undef _FORTIFY_SOURCE at the beginning of SmokeDMD.cpp. It's not like it matters in that file.

Comment 4

[Simon Giesecke [:sg] [he/him]]

Adding #undef _FORTIFY_SOURCE fixes the issue, and since you say this doesn't matter I will submit a patch to add that.

Comment 5

[Simon Giesecke [:sg] [he/him]]

Attachment: Bug 1601590 - Undef _FORTIFY_SOURCE to fix build with --warnings-on-errors. r=glandium

This is required on some systems such as Fedora to allow
building with -O0 together with --warnings-as-errors due to

a check in /usr/include/features.h

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3dc9cd6dfb53
Undef _FORTIFY_SOURCE to fix build with --warnings-on-errors. r=glandium

Comment 7

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/3dc9cd6dfb53