1666108 - GCC9 cc1plus: warning: ‘-Werror=’ argument ‘-Werror=implicit-function-declaration’ is not valid for C++

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[Nicklas Boman [:smurfd]]

Hey

So this below is my mozconfig file

export CC="/usr/bin/gcc-9"
export CXX="/usr/bin/g++-9"

mk_add_options PYTHON=/usr/bin/python3.6

ac_add_options --disable-elf-hack

# Debug builds
ac_add_options --enable-debug
ac_add_options --enable-debug-symbols
# Stricter builds
ac_add_options --enable-warnings-as-errors

# To fix _FORTIFY_SOURCE issues
ac_add_options --disable-hardening
#ac_add_options --enable-optimize

Steps to reproduce : Build with GCC9 (atleast on linux)
Actual results :
I receive ALOT(about 1600 warnings of a fresh m-c build) of these warnings :
cc1plus: warning: ‘-Werror=’ argument ‘-Werror=implicit-function-declaration’ is not valid for C++

Expected results : No warnings
Workaround : Seems that if i change to GCC8 i will not receive these warnings.

Comment 1

[Sylvestre Ledru [:Sylvestre]]

See
https://bugzilla.mozilla.org/show_bug.cgi?id=822978#c17

Comment 2

[Sylvestre Ledru [:Sylvestre]]

note: it breaks the build with --enable-warnings-as-errors
To make it build, I am using this ugly workaround:

sed -i -e "s|-Wno-unreachable-code-return||g"  security/sandbox/linux/moz.build 

As it is a bug in gcc, it doesn't break firefox (it is still possible to build it), I will just close this bug.

Comment 3

[Steve Fink [:sfink] [:s:]]

The hazard build logs are getting spammed with this, so I would prefer to fix it.

Comment 4

[Steve Fink [:sfink] [:s:]]

Attachment: Bug 1666108 - Eliminate -Wimplicit-function-declaration warnings

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6ed74fab9add
Eliminate -Wimplicit-function-declaration warnings r=firefox-build-system-reviewers,glandium

Comment 6

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/6ed74fab9add