[Patch, Fortran] Add stat=/errmsg= support to _gfortran_caf_register

[Tobias Burnus <burnus at net-b dot de>]

This patch cleans up the ABI mess, I created at some point.

The initial version of _gfortran_caf_register didn't handle stat/errmsg 
as one could leave it to the front end: The the returned memory is NULL, 
it's an error. However, as Nick pointed out, for stat= one can also 
return STAT_STOPPED_IMAGE. In order to handle this, one needs an 
additional argument.

That's what was done - albeit incompletely: The documentation was 
updated, cf. http://gcc.gnu.org/wiki/CoarrayLib#Registering_coarrays, as 
was the front end (cf. function declaration and call in trans-decl.c); 
however, the library itself (single.c and mpi.c) was not accepting the 
new arguments.

The attached patch solves this: It updates the just (by Daniel) added 
trans.c call and implements the new arguments in the library.

TODO: In trans.c (for the ALLOCATE statement), I currently pass NULL 
pointers for stat and errormsg argument. Hence, the ABI is fixed, but 
the error diagnostic is not yet standard conform. However, I think one 
can defer this to another patch. I added a note in my BUG file to make 
sure it won't get forgotten. Cf. 
http://users.physik.fu-berlin.de/~tburnus/coarray/BUGS.txt

Build and regtested on x86-64-linux.
OK for the trunk?

(Daniel Carrera, I would be happy if you could also have a look at the 
patch.)

Tobias
2011-07-06  Tobias Burnus  <burnus@net-b.de>

	* trans.c (gfc_allocate_with_status): Call _gfortran_caf_register
	with NULL arguments for (new) stat=/errmsg= arguments.

2011-07-06  Tobias Burnus  <burnus@net-b.de>

	* libcaf.h (__attribute__, unlikely, likely): New macros.
	(caf_register_t): Update comment.
	(_gfortran_caf_register): Add stat, errmsg, errmsg_len arguments.
	* single.c (_gfortran_caf_register): Ditto; add error diagnostics.
	* mpi.c (_gfortran_caf_register): Ditto.
	(caf_is_finalized): New global variable.
	(_gfortran_caf_finalize): Use it.

diff --git a/gcc/fortran/trans.c b/gcc/fortran/trans.c
index 683e3f1..4043df2 100644
--- a/gcc/fortran/trans.c
+++ b/gcc/fortran/trans.c
@@ -622,13 +622,16 @@ gfc_allocate_with_status (stmtblock_t * block, tree size, tree status,
       gfc_add_modify (&alloc_block, res,
 	      fold_convert (prvoid_type_node,
 		    build_call_expr_loc (input_location,
-			 gfor_fndecl_caf_register, 3,
+			 gfor_fndecl_caf_register, 6,
 			 fold_build2_loc (input_location,
 				  MAX_EXPR, size_type_node, size,
 				  build_int_cst (size_type_node, 1)),
 			 build_int_cst (integer_type_node,
 					GFC_CAF_COARRAY_ALLOC),
-			 null_pointer_node)));  /* Token */
+			 null_pointer_node,  /* token  */
+			 null_pointer_node,  /* stat  */
+			 null_pointer_node,  /* errmsg, errmsg_len  */
+			 build_int_cst (integer_type_node, 0))));
     }
   else
     {
diff --git a/libgfortran/caf/libcaf.h b/libgfortran/caf/libcaf.h
index 4177985..4fe09e4 100644
--- a/libgfortran/caf/libcaf.h
+++ b/libgfortran/caf/libcaf.h
@@ -30,6 +30,14 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #include <stdint.h>	/* For int32_t.  */
 #include <stddef.h>	/* For ptrdiff_t.  */
 
+#ifndef __GNUC__
+#define __attribute__(x)
+#define likely(x)       (x)
+#define unlikely(x)     (x)
+#else
+#define likely(x)       __builtin_expect(!!(x), 1)
+#define unlikely(x)     __builtin_expect(!!(x), 0)
+#endif
 
 /* Definitions of the Fortran 2008 standard; need to kept in sync with
    ISO_FORTRAN_ENV, cf. libgfortran.h.  */
@@ -38,7 +46,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define STAT_LOCKED_OTHER_IMAGE	2
 #define STAT_STOPPED_IMAGE 	3
 
-/* Describes what type of array we are registerring.  */
+/* Describes what type of array we are registerring. Keep in sync with
+   gcc/fortran/trans.h.  */
 typedef enum caf_register_t {
   CAF_REGTYPE_COARRAY_STATIC,
   CAF_REGTYPE_COARRAY_ALLOC,
@@ -58,7 +67,8 @@ caf_static_t;
 void _gfortran_caf_init (int *, char ***, int *, int *);
 void _gfortran_caf_finalize (void);
 
-void * _gfortran_caf_register (ptrdiff_t, caf_register_t, void **);
+void * _gfortran_caf_register (ptrdiff_t, caf_register_t, void **, int *,
+			       char *, int);
 int _gfortran_caf_deregister (void **);
 
 
diff --git a/libgfortran/caf/mpi.c b/libgfortran/caf/mpi.c
index 83f39f6..2d4af6b 100644
--- a/libgfortran/caf/mpi.c
+++ b/libgfortran/caf/mpi.c
@@ -41,6 +41,7 @@ static void error_stop (int error) __attribute__ ((noreturn));
 static int caf_mpi_initialized;
 static int caf_this_image;
 static int caf_num_images;
+static int caf_is_finalized;
 
 caf_static_t *caf_static_list = NULL;
 
@@ -87,14 +88,20 @@ _gfortran_caf_finalize (void)
 
   if (!caf_mpi_initialized)
     MPI_Finalize ();
+
+  caf_is_finalized = 1;
 }
 
 
 void *
-_gfortran_caf_register (ptrdiff_t size, caf_register_t type,
-                        void **token)
+_gfortran_caf_register (ptrdiff_t size, caf_register_t type, void **token,
+			int *stat, char *errmsg, int errmsg_len)
 {
   void *local;
+  int err;
+
+  if (unlikely (caf_is_finalized))
+    goto error;
 
   /* Start MPI if not already started.  */
   if (caf_num_images == 0)
@@ -103,10 +110,19 @@ _gfortran_caf_register (ptrdiff_t size, caf_register_t type,
   /* Token contains only a list of pointers.  */
   local = malloc (size);
   token = malloc (sizeof (void*) * caf_num_images);
+  
+  if (unlikely (local == NULL || token == NULL))
+    goto error;
 
   /* token[img-1] is the address of the token in image "img".  */
-  MPI_Allgather (&local, sizeof (void*), MPI_BYTE,
-		 token,  sizeof (void*), MPI_BYTE, MPI_COMM_WORLD);
+  err = MPI_Allgather (&local, sizeof (void*), MPI_BYTE, token,
+		       sizeof (void*), MPI_BYTE, MPI_COMM_WORLD);
+  if (unlikely (err))
+    {
+      free (local);
+      free (token);
+      goto error;
+    }
 
   if (type == CAF_REGTYPE_COARRAY_STATIC)
     {
@@ -115,7 +131,41 @@ _gfortran_caf_register (ptrdiff_t size, caf_register_t type,
       tmp->token = token;
       caf_static_list = tmp;
     }
+
+  if (stat)
+    *stat = 0;
+
   return local;
+
+error:
+  if (stat)
+    {
+      *stat = caf_is_finalized ? STAT_STOPPED_IMAGE : 1;
+      if (errmsg_len > 0)
+	{
+	  char *msg;
+          if (caf_is_finalized)
+	    msg = "Failed to allocate coarray - stopped images";
+	  else
+	    msg = "Failed to allocate coarray";
+	  int len = ((int) strlen (msg) > errmsg_len) ? errmsg_len
+						      : (int) strlen (msg);
+	  memcpy (errmsg, msg, len);
+	  if (errmsg_len > len)
+	    memset (&errmsg[len], ' ', errmsg_len-len);
+	}
+      return NULL;
+    }
+  else
+    {
+      if (caf_is_finalized)
+	fprintf (stderr, "ERROR: Image %d is stopped, failed to allocate "
+		 "coarray", caf_this_image);
+      else
+	fprintf (stderr, "ERROR: Failed to allocate coarray on image %d\n",
+		 caf_this_image);
+      error_stop (1);
+    }
 }
 
 
diff --git a/libgfortran/caf/single.c b/libgfortran/caf/single.c
index 5392797..603a910 100644
--- a/libgfortran/caf/single.c
+++ b/libgfortran/caf/single.c
@@ -27,6 +27,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #include "libcaf.h"
 #include <stdio.h>  /* For fputs and fprintf.  */
 #include <stdlib.h> /* For exit and malloc.  */
+#include <string.h> /* For memcpy and memset.  */
 
 /* Define GFC_CAF_CHECK to enable run-time checking.  */
 /* #define GFC_CAF_CHECK  1  */
@@ -61,8 +62,8 @@ _gfortran_caf_finalize (void)
 
 
 void *
-_gfortran_caf_register (ptrdiff_t size, caf_register_t type,
-			void **token)
+_gfortran_caf_register (ptrdiff_t size, caf_register_t type, void **token,
+			int *stat, char *errmsg, int errmsg_len)
 {
   void *local;
 
@@ -70,6 +71,32 @@ _gfortran_caf_register (ptrdiff_t size, caf_register_t type,
   token = malloc (sizeof (void*) * 1);
   token[0] = local;
 
+  if (unlikely (local == NULL || token == NULL))
+    {
+      if (stat)
+	{
+	  *stat = 1;
+	  if (errmsg_len > 0)
+	    {
+	      const char msg[] = "Failed to allocate coarray";
+	      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);
+	    }
+	  return NULL;
+	}
+      else
+	{
+	  fprintf (stderr, "ERROR: Failed to allocate coarray");
+	  exit (1);
+	}
+    }
+
+  if (stat)
+    *stat = 0;
+
   if (type == CAF_REGTYPE_COARRAY_STATIC)
     {
       caf_static_t *tmp = malloc (sizeof (caf_static_t));