[Bug libgcc/110017] New: Crossback Compilation for multilib fails on latest ubuntu due to -mx32 being disabled by the linux kernel

[Bug libgcc/110017] New: Crossback Compilation for multilib fails on latest ubuntu due to -mx32 being disabled by the linux kernel

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110017

            Bug ID: 110017
           Summary: Crossback Compilation for multilib fails on latest
                    ubuntu due to -mx32 being disabled by the linux kernel
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgcc
          Assignee: unassigned at gcc dot gnu.org
          Reporter: unlvsur at live dot com
  Target Milestone: ---

I attempted crossback compilation for GCC, where the compiler is built on
Linux, runs on Windows, and is targeted for Linux again. However, the build
system of libgcc includes a sanity test to detect the functionality of the
compiler, which prevents the build for the -mx32 option and disables m32.

Moreover, during crossback compilation, GCC specifically looks for the "cc"
command instead of just "gcc," even in cases where it doesn't exist.

Is there a way to remove or bypass the sanity test restriction for crossback
compilation in this scenario?

[Bug libgcc/110017] Crossback Compilation for multilib fails on latest ubuntu due to -mx32 being disabled by the linux kernel

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110017

--- Comment #1 from cqwrteur <unlvsur at live dot com> ---
(In reply to cqwrteur from comment #0)
> I attempted crossback compilation for GCC, where the compiler is built on
> Linux, runs on Windows, and is targeted for Linux again. However, the build
> system of libgcc includes a sanity test to detect the functionality of the
> compiler, which prevents the build for the -mx32 option and disables m32.
> 
> Moreover, during crossback compilation, GCC specifically looks for the "cc"
> command instead of just "gcc," even in cases where it doesn't exist.
> 
> Is there a way to remove or bypass the sanity test restriction for crossback
> compilation in this scenario?

Not the functionality. It detects whether -mx32 program could run but of course
it cannot because linux kernel disabled that.

[Bug libgcc/110017] Crossback Compilation for multilib fails on latest ubuntu due to -mx32 being disabled by the linux kernel

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110017

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-05-28
            Version|14.0                        |unknown
             Status|UNCONFIRMED                 |WAITING

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
How are you configuring GCC?

[Bug libgcc/110017] Crossback Compilation for multilib fails on latest ubuntu due to -mx32 being disabled by the linux kernel

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110017

--- Comment #3 from cqwrteur <unlvsur at live dot com> ---
(In reply to Andrew Pinski from comment #2)
> How are you configuring GCC?

gcc/configure --disable-nls --disable-werror --enable-languages=c,c++
--enable-multilib --with-multilib-list=m64,m32,mx32
--with-gxx-libcxx-include-dir=$PREFIXTARGET/include/c++/v1 --prefix=$PREFIX
--build=x86_64-pc-linux-gnu --host=x86_64-w64-mingw32
--target=x86_64-pc-linux-gnu --disable-bootstrap --disable-libstdcxx-verbose
--with-libstdcxx-eh-pool-obj-count=0 --enable-libstdcxx-backtrace

[Bug libgcc/110017] Crossback Compilation for multilib fails on latest ubuntu due to -mx32 being disabled by the linux kernel

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110017

--- Comment #4 from cqwrteur <unlvsur at live dot com> ---
Created attachment 55182
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55182&action=edit
Here is the build script (need to install a x86_64-w64-mingw32 cross compiler
first)