PR fortran/16336

* decl.c (gfc_match_save): Use-associated common block
doesn't collide.
* gfortran.h (gfc_common_head): Add new field 'name'.
Fix typo in comment after #endif.
* match.c (gfc_get_common): Add new argument from_common,
mangle name if flag is set, fill in new field in structure
gfc_common_head.
(match_common): Set new arg in call to gfc_get_common,
use-associated common block doesn't collide.
* match.h (gfc_get_common): Adapt prototype.
* module.c (load_commons): Set new arg in call to
gfc_get_common.
* symbol.c (free_common_tree): New function.
(gfc_free_namespace): Call new function.
* trans-common.c (several functions): Remove argument
'name', use name from gfc_common_head instead.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@84476 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 22 insertions, 13 deletions

diff --git a/gcc/fortran/match.c b/gcc/fortran/match.c
index 2d85a56cc7d..040142f766c 100644
--- a/gcc/fortran/match.c
+++ b/gcc/fortran/match.c
@@ -2049,22 +2049,38 @@ cleanup:
 
 
 /* Given a name, return a pointer to the common head structure,
-   creating it if it does not exist.
+   creating it if it does not exist. If FROM_MODULE is non-zero, we
+   mangle the name so that it doesn't interfere with commons defined 
+   in the using namespace.
    TODO: Add to global symbol tree.  */
 
 gfc_common_head *
-gfc_get_common (char *name)
+gfc_get_common (const char *name, int from_module)
 {
   gfc_symtree *st;
+  static int serial = 0;
+  char mangled_name[GFC_MAX_SYMBOL_LEN+1];
 
-  st = gfc_find_symtree (gfc_current_ns->common_root, name);
-  if (st == NULL)
-    st = gfc_new_symtree (&gfc_current_ns->common_root, name);
+  if (from_module)
+    {
+      /* A use associated common block is only needed to correctly layout
+	 the variables it contains.  */
+      snprintf(mangled_name, GFC_MAX_SYMBOL_LEN, "_%d_%s", serial++, name);
+      st = gfc_new_symtree (&gfc_current_ns->common_root, mangled_name);
+    }
+  else
+    {
+      st = gfc_find_symtree (gfc_current_ns->common_root, name);
+
+      if (st == NULL)
+	st = gfc_new_symtree (&gfc_current_ns->common_root, name);
+    }
 
   if (st->n.common == NULL)
     {
       st->n.common = gfc_get_common_head ();
       st->n.common->where = gfc_current_locus;
+      strcpy (st->n.common->name, name);
     }
 
   return st->n.common;
@@ -2140,15 +2156,8 @@ gfc_match_common (void)
 	}
       else
 	{
-	  t = gfc_get_common (name);
+	  t = gfc_get_common (name, 0);
 	  head = &t->head;
-
-	  if (t->use_assoc)
-	    {
-	      gfc_error ("COMMON block '%s' at %C has already "
-			 "been USE-associated", name);
-	      goto cleanup;
-	    }
 	}
 
       if (*head == NULL)