Bug 541262 – dev-qt/qtcore 5.4.0 fails to compile: x86_64-pc-linux-gnu-g++: error: unrecognized command line option ‘-fuse-ld=gold’

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description tobi 2015-02-24 16:59:19 UTC]

Created attachment 397426 [details]
emerge --info output

As the title says, when updating my system qtcore 5.4.0 fails to compile.

[Comment 1 tobi 2015-02-24 17:00:01 UTC]

Created attachment 397428 [details]
emerge -pqv output

[Comment 2 tobi 2015-02-24 17:01:28 UTC]

Created attachment 397430 [details]
build.log of qtcore failing

[Comment 3 Mike Gilbert 2015-02-24 17:20:03 UTC]

-fuse-ld was added in gcc-4.8. You currently have gcc-4.7 selected.

qtcore should probably be changed to detect that, or should ban usage of <gcc-4.8.

[Comment 4 tobi 2015-02-24 17:31:21 UTC]

Thanks for the fast answer. How do I change to a different gcc version? I can't find an eselect module for that.

[Comment 5 tobi 2015-02-24 17:33:31 UTC]

Nevermind, just found gcc-config.
Thanks for your effort and the fast solution to my problems.

[Comment 6 Davide Pesavento (RETIRED) 2015-02-24 17:35:43 UTC]

(In reply to Mike Gilbert from comment #3)
> qtcore should probably be changed to detect that, or should ban usage of
> <gcc-4.8.

qtbase configure script already has code to detect -fuse-ld=gold support. So something's wrong...

[Comment 7 Davide Pesavento (RETIRED) 2015-02-24 17:48:37 UTC]

The test is:

    if linkerSupportsFlag $TEST_COMPILER -fuse-ld=gold; then

which actually tests '-Wl,-fuse-ld=gold'. I guess linkerSupportsFlag should be changed to compilerSupportsFlag. Anyone with gcc-4.7 wants to try?

[Comment 8 Mike Gilbert 2015-02-24 17:51:42 UTC]

(In reply to Davide Pesavento from comment #7)
> The test is:
> 
>     if linkerSupportsFlag $TEST_COMPILER -fuse-ld=gold; then
> 
> which actually tests '-Wl,-fuse-ld=gold'. I guess linkerSupportsFlag should
> be changed to compilerSupportsFlag.

Right. -fuse-ld=gold is a gcc switch, not an ld switch. I see people get this wrong surprisingly frequently.

[Comment 9 Michael Palimaka (kensington) 2015-05-31 17:36:56 UTC]

In overlay, tested OK with gcc-4.7:

https://gitweb.gentoo.org/proj/qt.git/commit/?id=f6b7f47fb07fda8aa6e0c3be5be7f60c2d541b0d

[Comment 10 Davide Pesavento (RETIRED) 2015-05-31 19:06:10 UTC]

Michael, I've reverted your commit because this bug was already fixed upstream for 5.4.2

https://code.qt.io/cgit/qt/qtbase.git/commit/?id=53e2db74dba8135bd88bad48fbf9f2fc81ed4f8b

[Comment 11 Davide Pesavento (RETIRED) 2015-06-17 15:58:55 UTC]

fixed in 5.4.2