ELL unit test problem with Link Time Optimization, l_getrandom, test-ecdh

ELL unit test problem with Link Time Optimization, l_getrandom, test-ecdh

[Gix, Brian]

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While examining my BlueZ issues with building with LTO, I came accross 
the following issue in the ELL unit test of ECDH:


.../ell > export CFLAGS="-flto=auto"
.../ell > ./bootstrap-configure
.../ell > make
make --no-print-directory all-am
  CCLD     unit/test-ecdh
/usr/lib64/gcc/x86_64-suse-linux/9/../../../../x86_64-suse-linux/bin/ld: /tmp/test-
ecdh.XGzxNu.ltrans0.ltrans.o: in function `__wrap_l_getrandom':
/home/bgix/work/user_space/ell/unit/test-ecdh.c:52: undefined reference to `l_getrandom'
collect2: error: ld returned 1 exit status
make[1]: *** [Makefile:1541: unit/test-ecdh] Error 1
make: *** [Makefile:1190: all] Error 2


This is on an up-to-date openSUSE tumbleweed VM, and I have been told that building with the LTO flag is the
preferred build method on that system.  This problem does not seem to affect anything *except* that one unit
test, and is probably related to the explicit link rule for it in Makefile.am:

unit_test_ecdh_LDFLAGS = -Wl,-wrap,l_getrandom

Re: ELL unit test problem with Link Time Optimization, l_getrandom, test-ecdh

[Othman, Ossama]

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On Wed, Nov 6, 2019 at 8:50 AM Gix, Brian <brian.gix@intel.com> wrote:
>   CCLD     unit/test-ecdh
> /usr/lib64/gcc/x86_64-suse-linux/9/../../../../x86_64-suse-linux/bin/ld: /tmp/test-
> ecdh.XGzxNu.ltrans0.ltrans.o: in function `__wrap_l_getrandom':
> /home/bgix/work/user_space/ell/unit/test-ecdh.c:52: undefined reference to `l_getrandom'
> collect2: error: ld returned 1 exit status
> make[1]: *** [Makefile:1541: unit/test-ecdh] Error 1
> make: *** [Makefile:1190: all] Error 2

FWIW, I can reproduce this issue on my Ubuntu 19.10 box:

$ make CFLAGS=-flto check
...
  CC       unit/test-ecdh.o
 CCLD     unit/test-ecdh
/usr/bin/ld: /tmp/test-ecdh.guYgVf.ltrans0.ltrans.o: in function `__wrap_l_getra
ndom':
<artificial>:(.text+0x2a): undefined reference to `l_getrandom'
collect2: error: ld returned 1 exit status
make[3]: *** [Makefile:1542: unit/test-ecdh] Error 1

-Ossama

Re: ELL unit test problem with Link Time Optimization, l_getrandom, test-ecdh

[Denis Kenzior]

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Hi Brian,

On 11/6/19 10:50 AM, Gix, Brian wrote:
> While examining my BlueZ issues with building with LTO, I came accross
> the following issue in the ELL unit test of ECDH:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88643

May I suggest that the distro in question figures this out by 
themselves, there's nothing wrong in ell.

If they insist on using LTO, then at least disable it for that test.

Regards,
-Denis