Re: [PATCH] gcc/Makefile.in: move SELFTEST_DEPS before including language makefile fragments

[Jeff Law <law@redhat.com>]

On Thu, 2020-05-21 at 17:35 +0200, Romain Naour via Gcc-patches wrote:
> As reported by several Buildroot users [1][2][3], the gcc build
> may fail while running selftests makefile target.
> 
> The problem only occurs when ccache is used with gcc 9 and 10,
> probably due to a race condition.
> 
> While debuging with "make -p" we can notice that s-selftest-c target
> contain only "cc1" as dependency instead of cc1 and SELFTEST_DEPS [4].
> 
>   s-selftest-c: cc1
> 
> While the build is failing, the s-selftest-c dependencies recipe is
> still running and reported as a bug by make.
> 
>   "Dependencies recipe running (THIS IS A BUG)."
> 
> A change [5] in gcc 9 seems to introduce the problem since we can't
> reproduce this problem with gcc 8.
> 
> As suggested by Yann E. MORIN [6], move SELFTEST_DEPS before
> including language makefile fragments.
> 
> With the fix applied, the s-seltest-c dependency contains
> SELFTEST_DEPS value.
> 
>   s-selftest-c: cc1 xgcc specs stmp-int-hdrs ../../gcc/testsuite/selftests
> 
> [1] http://lists.busybox.net/pipermail/buildroot/2020-May/282171.html
> [2] http://lists.busybox.net/pipermail/buildroot/2020-May/282766.html
> [3] https://github.com/cirosantilli/linux-kernel-module-cheat/issues/108
> [4] 
> https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/c/Make-lang.in;h=bfae6fd2549c4f728816cd355fa9739dcc08fcde;hb=033eb5671769a4c681a44aad08a454e667e08502#l120
> [5] 
> https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=033eb5671769a4c681a44aad08a454e667e08502
> [6] http://lists.busybox.net/pipermail/buildroot/2020-May/283213.html
> 
> Signed-off-by: Romain Naour <romain.naour@gmail.com>
> Cc: Ben Dakin-Norris <ben.dakin-norris@navtechradar.com>
> Cc: Maxim Kochetkov <fido_max@inbox.ru>
> Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> Cc: Yann E. MORIN <yann.morin.1998@free.fr>
> Cc: Cc: David Malcolm <dmalcolm@gcc.gnu.org>
> ---
> This patch should be backported to gcc 10 and gcc 9.
> ---
>  gcc/ChangeLog   | 5 +++++
>  gcc/Makefile.in | 6 ++++--
>  2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
> index 977e7664b62..c3bb18f2afd 100644
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,8 @@
> +2020-05-21  Romain Naour <romain.naour@gmail.com>
> +
> +	* Makefile.in: move SELFTEST_DEPS before including language
> +	makefile fragments.
THanks.  I've installed this on the trunk.

jeff
>