gcc/libgfortran/caf/mpi.c

212 lines
5.4 KiB
C

/* MPI implementation of GNU Fortran Coarray Library
Copyright (C) 2011
Free Software Foundation, Inc.
Contributed by Tobias Burnus <burnus@net-b.de>
This file is part of the GNU Fortran Coarray Runtime Library (libcaf).
Libcaf is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
Libcaf is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "libcaf.h"
#include <stdio.h>
#include <stdlib.h>
#include <mpi.h>
/* Define GFC_CAF_CHECK to enable run-time checking. */
/* #define GFC_CAF_CHECK 1 */
static void error_stop (int error) __attribute__ ((noreturn));
/* Global variables. */
static int caf_this_image;
static int caf_num_images;
static MPI_Win caf_world_window;
/* Initialize coarray program. This routine assumes that no other
MPI initialization happened before; otherwise MPI_Initialized
had to be used. As the MPI library might modify the command-line
arguments, the routine should be called before the run-time
libaray is initialized. */
void
_gfortran_caf_init (int *argc, char ***argv, int *this_image, int *num_images)
{
int flag;
/* The following is only the case if one does not have a Fortran
main program. */
MPI_Initialized (&flag);
if (!flag)
MPI_Init (argc, argv);
MPI_Comm_rank (MPI_COMM_WORLD, &caf_this_image);
*this_image = caf_this_image + 1;
MPI_Comm_size (MPI_COMM_WORLD, &caf_num_images);
*num_images = caf_num_images;
/* Obtain window for CRITICAL section locking. */
MPI_Win_create (NULL, 0, 1, MPI_INFO_NULL, MPI_COMM_WORLD,
&caf_world_window);
}
/* Finalize coarray program. Note: This is only called before the
program ends; thus the MPI_Initialized status of _gfortran_caf_init
does not play a role. */
void
_gfortran_caf_finalize (void)
{
MPI_Win_free (&caf_world_window);
MPI_Finalize ();
}
/* SYNC ALL - the return value matches Fortran's STAT argument. */
int
_gfortran_caf_sync_all (char *errmsg, int errmsg_len)
{
int ierr;
ierr = MPI_Barrier (MPI_COMM_WORLD);
if (ierr && errmsg_len > 0)
{
const char msg[] = "SYNC ALL failed";
int len = ((int) sizeof (msg) > errmsg_len) ? errmsg_len
: (int) sizeof (msg);
memcpy (errmsg, msg, len);
if (errmsg_len > len)
memset (&errmsg[len], ' ', errmsg_len-len);
}
/* TODO: Is ierr correct? When should STAT_STOPPED_IMAGE be used? */
return ierr;
}
/* SYNC IMAGES. Note: SYNC IMAGES(*) is passed as count == -1 while
SYNC IMAGES([]) has count == 0. Note further that SYNC IMAGES(*)
is not equivalent to SYNC ALL. The return value matches Fortran's
STAT argument. */
int
_gfortran_caf_sync_images (int count, int images[], char *errmsg,
int errmsg_len)
{
int ierr;
if (count == 0 || (count == 1 && images[0] == caf_this_image))
return 0;
#ifdef GFC_CAF_CHECK
{
int i;
for (i = 0; i < count; i++)
if (images[i] < 1 || images[i] > caf_num_images)
{
fprintf (stderr, "COARRAY ERROR: Invalid image index %d to SYNC "
"IMAGES", images[i]);
error_stop (1);
}
}
#endif
/* FIXME: SYNC IMAGES with a nontrivial argument cannot easily be
mapped to MPI communicators. Thus, exist early with an error message. */
if (count > 0)
{
fprintf (stderr, "COARRAY ERROR: SYNC IMAGES not yet implemented");
error_stop (1);
}
/* Handle SYNC IMAGES(*). */
ierr = MPI_Barrier (MPI_COMM_WORLD);
if (ierr && errmsg_len > 0)
{
const char msg[] = "SYNC IMAGES failed";
int len = ((int) sizeof (msg) > errmsg_len) ? errmsg_len
: (int) sizeof (msg);
memcpy (errmsg, msg, len);
if (errmsg_len > len)
memset (&errmsg[len], ' ', errmsg_len-len);
}
/* TODO: Is ierr correct? When should STAT_STOPPED_IMAGE be used? */
return ierr;
}
/* CRITICAL BLOCK. */
void
_gfortran_caf_critical (void)
{
MPI_Win_lock (MPI_LOCK_SHARED, 0, 0, caf_world_window);
}
void
_gfortran_caf_end_critical (void)
{
MPI_Win_unlock (0, caf_world_window);
}
/* ERROR STOP the other images. */
static void
error_stop (int error)
{
/* FIXME: Shutdown the Fortran RTL to flush the buffer. PR 43849. */
/* FIXME: Do some more effort than just MPI_ABORT. */
MPI_Abort (MPI_COMM_WORLD, error);
/* Should be unreachable, but to make sure also call exit. */
exit (error);
}
/* ERROR STOP function for string arguments. */
void
_gfortran_caf_error_stop_str (const char *string, int32_t len)
{
fputs ("ERROR STOP ", stderr);
while (len--)
fputc (*(string++), stderr);
fputs ("\n", stderr);
error_stop (1);
}
/* ERROR STOP function for numerical arguments. */
void
_gfortran_caf_error_stop (int32_t error)
{
fprintf (stderr, "ERROR STOP %d\n", error);
error_stop (error);
}