Bug 500046

Summary:	sys-apps/sed-4.2.1 CFLAGS="-O3 -DNDEBUG" - no POSIX character classes
Product:	Gentoo Linux	Reporter:	Guenther Brunthaler <gb_about_gnu>
Component:	[OLD] Core system	Assignee:	Gentoo's Team for Core System packages <base-system>
Status:	RESOLVED OBSOLETE
Severity:	normal
Priority:	Normal
Version:	unspecified
Hardware:	AMD64
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---
Attachments:	Output of emerge --info configure log from the sandboxed build environment

Description Guenther Brunthaler 2014-02-02 05:46:09 UTC

sys-apps/sed-4.2.1-r1 builds an inferior executable which does not support POSIX character classes such as [:space:] if both -O3 and -DNDEBUG are used as compiler flags with gcc-4.7.3.

This makes other package builds fail, for example dev-libs/elfutils.

Reproducible: Always

Steps to Reproduce:
1. Include -O3 in CFLAGS and -DNDEBUG in CPPFLAGS in make.conf
2. Emerge sys-apps/sed. No errors are reported.
3. Try command: echo before after | sed -e 's/[[:space:]]/x/g'
Actual Results:  
sed: -e expression #1, char 17: Unmatched [ or [^


Expected Results:  
beforexafter

ANSI C allows to define the NBDEBUG preprocessor flag which expands all assert() macro invocations as no-op statements.

Combined with -O3 this creates highly-optimized high-speed executables with assert()-runtime checks effectively removed.

A correct executable should behave identically whether assert() checks are removed or not.

sed-4.2.1 is broken: It supports POSIX character classes when built with -O2 or without -DNDEBUG, but it does no longer recognize POSIX character classes if built with both -O3 and -DNDEBUG.

Recommendation: Filter out -O* flags and always use -O2 until upstream has fixed this bug. I will report the bug upstream as well.

Comment 1 SpanKY gentoo-dev

2014-02-16 19:14:39 UTC

can't reproduce.  we don't filter flags in ebuilds either.

you must post `emerge --info` in every bug report as an attachment.  a full build log is also useful.

Comment 2 Guenther Brunthaler 2014-02-16 19:37:36 UTC

Created attachment 370580 [details]
Output of emerge --info

Comment 3 Guenther Brunthaler 2014-02-16 19:38:49 UTC

Created attachment 370582 [details]
configure log from the sandboxed build environment

Comment 4 Guenther Brunthaler 2014-02-16 19:45:52 UTC

(In reply to SpanKY from comment #1)
> can't reproduce.  we don't filter flags in ebuilds either.

I know, that's the problem here.

Of course this is an upstream bug, but upstream has been un-cooperative so far (seems to be stressed out by Gentoo users).

The bug is somehow linked to improper use of assert() and only surfaces with -O3 optimizations when the assert()s are removed (-DNDEBUG).

Filtering out optimization levels larger than 2 seem to avoid the bug. Also note that I have an amd64 system; perhaps the bug does not show on x86.

> you must post `emerge --info` in every bug report as an attachment.  a full
> build log is also useful.

I have attached both.

Comment 5 SpanKY gentoo-dev

2014-02-17 06:06:50 UTC

i can reproduce with 4.2.1, but not 4.2.2.  so i don't see the point in spending any time on this.

Comment 6 Guenther Brunthaler 2014-02-17 22:45:55 UTC

(In reply to SpanKY from comment #5)
> i can reproduce with 4.2.1, but not 4.2.2.  so i don't see the point in
> spending any time on this.

That's good news!

Seems a good idea to stabilize 4.2.2 then, because 4.2.1 is the newest stable version... "stable" being a relative term in this case.

Until then, I'll unmask 4.2.2.

Thanks!