[Bug bootstrap/96160] New: Building gcc with multiple make jobs fails with: gcc/xgcc: No such file or directory

[Bug bootstrap/96160] New: Building gcc with multiple make jobs fails with: gcc/xgcc: No such file or directory

[plevine457 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96160

            Bug ID: 96160
           Summary: Building gcc with multiple make jobs fails with:
                    gcc/xgcc: No such file or directory
           Product: gcc
           Version: 10.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
          Assignee: unassigned at gcc dot gnu.org
          Reporter: plevine457 at gmail dot com
  Target Milestone: ---

Created attachment 48860
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48860&action=edit
build.log.bz2

Building GCC with multiple make jobs appears to trigger a race condition.  The
build often fails with:

> /var/tmp/portage/sys-devel/gcc-10.1.0-r1/work/build/./gcc/xgcc -B/var/tmp/portage/sys-devel/gcc-10.1.0-r1/work/build/./gcc/ -xc++ -nostdinc /dev/null -S -o /dev/null -fself-test=/var/tmp/portage/sys-devel/gcc-10.1.0-r1/work/gcc-10.1.0/gcc/testsuite/selftests
> /bin/bash: /var/tmp/portage/sys-devel/gcc-10.1.0-r1/work/build/./gcc/xgcc: No such file or directory
> make[3]: *** [/var/tmp/portage/sys-devel/gcc-10.1.0-r1/work/gcc-10.1.0/gcc/cp/Make-lang.in:178: s-selftest-c++] Error 127

This has been noticeable at least since GCC-9.x.

Reported downstream at https://bugs.gentoo.org/728304.
Likely related to
https://github.com/cirosantilli/linux-kernel-module-cheat/issues/108

uname: Linux Laptop-PC 5.7.8-gentoo #1 SMP Fri Jul 10 04:05:05 EDT 2020 x86_64
Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz GenuineIntel GNU/Linux

[Bug bootstrap/96160] Building gcc with multiple make jobs fails with: gcc/xgcc: No such file or directory

[plevine457 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96160

--- Comment #1 from plevine457 at gmail dot com ---
Created attachment 48861
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48861&action=edit
gcc-10.1.0-xgcc-selftest-makeopts.patch

This patch appears to resolve the issue on my end

[Bug bootstrap/96160] Building gcc with multiple make jobs fails with: gcc/xgcc: No such file or directory

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96160

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Makefile.in:
GCC_PASSES=xgcc$(exeext) specs

SELFTEST_DEPS = $(GCC_PASSES) stmp-int-hdrs $(srcdir)/testsuite/selftests


c/Make-lang.in

C_SELFTEST_DEPS = cc1$(exeext) $(SELFTEST_DEPS)
...

s-selftest-c: $(C_SELFTEST_DEPS)

cp/Make-lang.in:
CPP_SELFTEST_DEPS = cc1plus$(exeext) $(SELFTEST_DEPS)
...
selftest-c++: s-selftest-c++
...
s-selftest-c++: $(CPP_SELFTEST_DEPS)

---- CUT ---

This looks correct to me.  xgcc is there already in the depends of
s-selftest-c++.
Which make version are you using?

[Bug bootstrap/96160] Building gcc with multiple make jobs fails with: gcc/xgcc: No such file or directory

[plevine457 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96160

--- Comment #3 from plevine457 at gmail dot com ---
> Which make version are you using?
GNU Make 4.3

[Bug bootstrap/96160] Building gcc with multiple make jobs fails with: gcc/xgcc: No such file or directory

[plevine457 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96160

--- Comment #4 from plevine457 at gmail dot com ---
The offending command is
> /var/tmp/portage/sys-devel/gcc-10.1.0-r1/work/build/./gcc/xgcc -B/var/tmp/portage/sys-devel/gcc-10.1.0-r1/work/build/./gcc/ -xc++ -nostdinc /dev/null -S -o /dev/null -fself-test=/var/tmp/portage/sys-devel/gcc-10.1.0-r1/work/gcc-10.1.0/gcc/testsuite/selftests

I would presume that there's no reason why gcc would emit "-o /dev/null" 
though I have seen it whaile using ccache.  

Looking further at
https://github.com/buildroot/buildroot/commit/58ecbbc3ef18c43ae1c02a5c4bf30aa7ef2d8092,
with regard to s-selftest-c:

> 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.

So this is likely a ccache bug.

[Bug bootstrap/96160] Building gcc with multiple make jobs fails with: gcc/xgcc: No such file or directory

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96160

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |build
             Status|UNCONFIRMED                 |RESOLVED
   Target Milestone|---                         |11.0
         Resolution|---                         |FIXED

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Has been fixed since June of last year with r11-881.

[Bug bootstrap/96160] Building gcc with multiple make jobs fails with: gcc/xgcc: No such file or directory

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96160

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |enrico.scholz+bugsgcc@sigma
                   |                            |-chemnitz.de

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 95840 has been marked as a duplicate of this bug. ***