[patch, fortran] Emit error for recursive I/O

[Thomas Koenig]

Hello world,

the attached patch hijacks Jerry's version and adds logic which
should make everything thread-safe. (Jerry, I hope you don't mind
this).

The rest is in the ChangeLog and in the comments.

OK for trunk?

Best regards

	Thomas

Generate a runtime error on recursive I/O, thread-safe

This patch is a version of Jerry's patch with one additional feature.
When locking a unit, the thread ID of the locking thread also stored
in the gfc_unit structure. When the unit is found to be locked, it can
be either have been locked by the same thread (bad, recursive I/O) or
by another thread (harmless).

Regression-tested fully (make -j8 check in the gcc build directory) on
Linux, which links in pthreads by default.  Steve checked on FreeBSD,
which does not do so.

OK for trunk?

Best regards

	Thomas

Jerry DeLisle  <jvdelisle@gcc.gnu.org>
Thomas Koenig <tkoenig@gcc.gnu.org>

PR libfortran/119136

gcc/fortran/ChangeLog:

         * libgfortran.h: Add enum for new LIBERROR_RECURSIVE_IO.

libgfortran/ChangeLog:

         * io/async.h (UNLOCK_UNIT): New macro.
         (TRYLOCK_UNIT): New macro.
         (LOCK_UNIT): New macro.
         * io/io.h: Delete prototype for unused stash_internal_unit.
         (check_for_recursive): Add prototype for this new function.
         * io/transfer.c (data_transfer_init): Add call to new
         check_for_recursive.
         * io/unit.c (delete_unit): Fix comment.
         (check_for_recursive): Add new function.
         (init_units): Use new macros.
         (close_unit_1): Likewise.
         (unlock_unit): Likewise.
         * io/unix.c (flush_all_units_1): Likewise.
         (flush_all_units): Likewise.
         * runtime/error.c (translate_error): : Add translation for
         "Recursive I/O not allowed runtime error message.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr119136.f90: New test.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: p1.diff
Type: text/x-patch
Size: 10260 bytes
Desc: not available
URL: <https://gcc.gnu.org/pipermail/fortran/attachments/20260104/02ebfc36/attachment-0001.bin>