re PR fortran/27269 (Segfault with EQUIVALENCEs in modules together with ONLY clauses)

2006-05-02 Paul Thomas <pault@gcc.gnu.org>

        PR fortran/27269
        * module.c: Add static flag in_load_equiv.
        (mio_expr_ref): Return if no symtree and in_load_equiv.
        (load_equiv): If any of the equivalence members have no symtree, free
        the equivalence and the associated expressions.

        PR fortran/27324
        * trans-common.c (gfc_trans_common): Invert the order of calls to
        finish equivalences and gfc_commit_symbols.

        PR fortran/27269
        PR fortran/27324
        * gfortran.dg/module_equivalence_2.f90: New test.

From-SVN: r113465

gcc/fortran/ChangeLog

@@ -1,3 +1,15 @@
+2006-05-02 Paul Thomas <pault@gcc.gnu.org>
+
+        PR fortran/27269
+        * module.c: Add static flag in_load_equiv.
+        (mio_expr_ref): Return if no symtree and in_load_equiv.
+        (load_equiv): If any of the equivalence members have no symtree, free
+        the equivalence and the associated expressions.
+
+        PR fortran/27324
+        * trans-common.c (gfc_trans_common): Invert the order of calls to
+        finish equivalences and gfc_commit_symbols.
+
 2006-04-29  Francois-Xavier Coudert  <coudert@clipper.ens.fr>
 
 	PR fortran/25681

gcc/fortran/module.c

@@ -182,6 +182,9 @@ static gfc_use_rename *gfc_rename_list;
 static pointer_info *pi_root;
 static int symbol_number;	/* Counter for assigning symbol numbers */
 
+/* Tells mio_expr_ref not to load unused equivalence members.  */
+static bool in_load_equiv;
+
 
 
 /*****************************************************************/
@@ -2135,6 +2138,11 @@ mio_symtree_ref (gfc_symtree ** stp)
     {
       require_atom (ATOM_INTEGER);
       p = get_integer (atom_int);
+
+      /* An unused equivalence member; bail out.  */
+      if (in_load_equiv && p->u.rsym.symtree == NULL)
+	return;
+      
       if (p->type == P_UNKNOWN)
         p->type = P_SYMBOL;
 
@@ -3008,14 +3016,18 @@ load_commons(void)
   mio_rparen();
 }
 
-/* load_equiv()-- Load equivalences. */
+/* load_equiv()-- Load equivalences. The flag in_load_equiv informs
+   mio_expr_ref of this so that unused variables are not loaded and
+   so that the expression can be safely freed.*/
 
 static void
 load_equiv(void)
 {
-  gfc_equiv *head, *tail, *end;
+  gfc_equiv *head, *tail, *end, *eq;
+  bool unused;
 
   mio_lparen();
+  in_load_equiv = true;
 
   end = gfc_current_ns->equiv;
   while(end != NULL && end->next != NULL)
@@ -3039,16 +3051,40 @@ load_equiv(void)
 	mio_expr(&tail->expr);
       }
 
+    /* Unused variables have no symtree.  */
+    unused = false;
+    for (eq = head; eq; eq = eq->eq)
+      {
+	if (!eq->expr->symtree)
+	  {
+	    unused = true;
+	    break;
+	  }
+      }
+
+    if (unused)
+      {
+	for (eq = head; eq; eq = head)
+	  {
+	    head = eq->eq;
+	    gfc_free_expr (eq->expr);
+	    gfc_free (eq);
+	  }
+      }
+
     if (end == NULL)
       gfc_current_ns->equiv = head;
     else
       end->next = head;
 
-    end = head;
+    if (head != NULL)
+      end = head;
+
     mio_rparen();
   }
 
   mio_rparen();
+  in_load_equiv = false;
 }
 
 /* Recursive function to traverse the pointer_info tree and load a

gcc/fortran/trans-common.c

@@ -1057,9 +1057,10 @@ gfc_trans_common (gfc_namespace *ns)
   /* Translate all named common blocks.  */
   gfc_traverse_symtree (ns->common_root, named_common);
 
-  /* Commit the newly created symbols for common blocks.  */
-  gfc_commit_symbols ();
-
   /* Translate local equivalence.  */
   finish_equivalences (ns);
+
+  /* Commit the newly created symbols for common blocks and module
+     equivalences.  */
+  gfc_commit_symbols ();
 }

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2006-05-02 Paul Thomas <pault@gcc.gnu.org>
+
+        PR fortran/27269
+        PR fortran/27324
+        * gfortran.dg/module_equivalence_2.f90: New test.
+
 2006-05-02  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/27337

gcc/testsuite/gfortran.dg/module_equivalence_2.f90

@@ -0,0 +1,24 @@
+! { dg-do run }
+! Tests the fix for PR27269 and PR27xxx.
+! The former caused a segfault in trying to process
+! module b, with an unused equivalence in a. The latter
+! produced an assembler error due to multiple declarations
+! for a module equivalence, when one of the variables was
+! initialized, as M in module a.
+!
+module a
+  integer, parameter :: dp = selected_real_kind (10)
+  real(dp) :: reM, M = 1.77d0
+  equivalence (M, reM)
+end module a
+
+module b
+  use a, only : dp
+end module b
+
+  use a
+  use b
+  if (reM .ne. 1.77d0) call abort ()
+  reM = 0.57d1
+  if (M .ne. 0.57d1) call abort ()
+end