re PR fortran/18918 (Eventually support Fortran 2008's coarrays [co-arrays])

2011-03-27  Tobias Burnus  <burnus@net-b.de>

        PR fortran/18918
        * caf/libcaf.h: New - coarray communication library.
        * caf/mpi.c: New.
        * caf/single.c: New.

From-SVN: r171570

libgfortran/ChangeLog

+2011-03-27  Tobias Burnus  <burnus@net-b.de>
+
+	PR fortran/18918
+	* caf/libcaf.h: New - coarray communication library.
+	* caf/mpi.c: New.
+	* caf/single.c: New.
+
 2011-03-23  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/48030

libgfortran/caf/libcaf.h

+/* Common declarations for all of GNU Fortran libcaf implementations.
+   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/>.  */
+
+#ifndef LIBCAF_H
+#define LIBCAF_H
+
+#include <stdint.h>
+#include <string.h>
+
+/* Definitions of the Fortran 2008 standard; need to kept in sync with
+   ISO_FORTRAN_ENV, cf. libgfortran.h.  */
+#define STAT_UNLOCKED		0
+#define STAT_LOCKED		1
+#define STAT_LOCKED_OTHER_IMAGE	2
+#define STAT_STOPPED_IMAGE 	3
+
+
+void _gfortran_caf_init (int *, char ***, int *, int *);
+void _gfortran_caf_finalize (void);
+
+int _gfortran_caf_sync_all (char *, int);
+int _gfortran_caf_sync_images (int count, int images[], char *, int);
+
+void _gfortran_caf_critical (void);
+void _gfortran_caf_end_critical (void);
+
+void _gfortran_caf_error_stop_str (const char *, int32_t) __attribute__ ((noreturn));
+void _gfortran_caf_error_stop (int32_t) __attribute__ ((noreturn));
+
+#endif  /* LIBCAF_H  */

libgfortran/caf/mpi.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);
+}

libgfortran/caf/single.c

+/* Single-image 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>  /* For fputs and fprintf.  */
+#include <stdlib.h> /* For exit.  */
+
+/* Define GFC_CAF_CHECK to enable run-time checking.  */
+/* #define GFC_CAF_CHECK  1  */
+
+
+/* Single-image implementation of the CAF library.
+   Note: For performance reasons -fcoarry=single should be used
+   rather than this library.  */
+
+void
+_gfortran_caf_init (int *argc __attribute__ ((unused)),
+		    char ***argv __attribute__ ((unused)),
+		    int *this_image, int *num_images)
+{
+  *this_image = 1;
+  *num_images = 1;
+}
+
+void
+_gfortran_caf_finalize (void)
+{
+}
+
+int
+_gfortran_caf_sync_all (char *errmsg __attribute__ ((unused)),
+			int errmsg_len __attribute__ ((unused)))
+{
+  return 0;
+}
+
+int
+_gfortran_caf_sync_images (int count __attribute__ ((unused)),
+			   int images[] __attribute__ ((unused)),
+			   char *errmsg __attribute__ ((unused)),
+			   int errmsg_len __attribute__ ((unused)))
+{
+#ifdef GFC_CAF_CHECK
+  int i;
+
+  for (i = 0; i < count; i++)
+    if (images[i] != 1)
+      {
+	fprintf (stderr, "COARRAY ERROR: Invalid image index %d to SYNC "
+		 "IMAGES", images[i]);
+	exit (1);
+      }
+#endif
+
+  return 0;
+}
+
+void
+_gfortran_caf_critical (void)
+{
+}
+
+void
+_gfortran_caf_end_critical (void)
+{
+}
+
+void
+_gfortran_caf_error_stop_str (const char *string, int32_t len)
+{
+  fputs ("ERROR STOP ", stderr);
+  while (len--)
+    fputc (*(string++), stderr);
+  fputs ("\n", stderr);
+
+  exit (1);
+}
+
+void
+_gfortran_caf_error_stop (int32_t error)
+{
+  fprintf (stderr, "ERROR STOP %d\n", error);
+  exit (error);
+}