Bug 335883

Summary:	cross-avr/gcc stage2 build fails with USE="openmp" due to missing pthreads
Product:	Gentoo Linux	Reporter:	Carlos Silva <r3pek>
Component:	[OLD] Core system	Assignee:	Gentoo Toolchain Maintainers <toolchain>
Status:	RESOLVED FIXED
Severity:	normal
Priority:	High
Version:	unspecified
Hardware:	AMD64
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Carlos Silva 2010-09-03 21:15:19 UTC

When setting up avr toolchain with crossdev, the default use flags passed to the gcc package make it fail the compilation.
This is caused by the openmp use flag and the error is "this gcc version can't compile programs" (don't have the exact text right now 'cause it takes a whole lot of time to compile on my box)

Reproducible: Always

Steps to Reproduce:
1. emerge crossdev
2. emerge -v -S --arch avr
3. watch it fail

Actual Results:  
failed to compile gcc

Expected Results:  
Compile the toolchain and be usable

Comment 1 Norman Yarvin 2010-09-08 08:11:46 UTC

I also encountered this bug, and, indeed, turning off the openmp USE flag on cross-avr/gcc fixed it.  The exact error message is:

------

Configuring in avr/libgomp
configure: creating cache ./config.cache
checking for --enable-version-specific-runtime-libs... no
checking for --enable-generated-files-in-srcdir... no
checking build system type... x86_64-pc-linux-gnu
checking host system type... avr-unknown-none
checking target system type... avr-unknown-none
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking for avr-strip... /usr/libexec/gcc/avr/strip
checking for avr-gcc... /var/tmp/portage/cross/avr/portage/cross-avr/gcc-4.4.4-r1/work/build/./gcc/xgcc -B/var/tmp/portage/cross/avr/portage/cross-avr/gcc-4.4.4-r1/work/build/./gcc/ -B/usr/avr/bin/ -B/usr/avr/lib/ -isystem /usr/avr/include -isystem /usr/avr/sys-include
checking for C compiler default output file name... configure: error: in `/var/tmp/portage/cross/avr/portage/cross-avr/gcc-4.4.4-r1/work/build/avr/libgomp':
configure: error: C compiler cannot create executables

------

OpenMP is of course not a lot of use on an 8-bit processor (to put it mildly), so it'd be good if crossdev turned it off by default, like all the other things it turns off.

Comment 2 SpanKY gentoo-dev

2010-10-10 07:29:02 UTC

openmp is automatically disabled now when C library lacks pthreads support

http://sources.gentoo.org/eclass/toolchain.eclass?r1=1.439&r2=1.440