re PR fortran/16939 (Pointers not passed as subroutine arguments)

2005-05-29 Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/16939
	PR fortran/17192
	PR fortran/17193
	PR fortran/17202
	PR fortran/18689
	PR fortran/18890
	PR fortran/21297
	* fortran/trans-array.c (gfc_conv_resolve_dependencies): Add string
	length to temp_ss for character pointer array assignments.
	* fortran/trans-expr.c (gfc_conv_variable): Correct errors in
	dereferencing of characters and character pointers.
	* fortran/trans-expr.c (gfc_conv_function_call): Provide string
	length as return argument for various kinds of handling of return.
	Return a char[]* temporary for character pointer functions and
	dereference the temporary upon return.

From-SVN: r100324

gcc/fortran/trans-array.c

@@ -2342,7 +2342,7 @@ gfc_conv_resolve_dependencies (gfc_loopinfo * loop, gfc_ss * dest,
       loop->temp_ss->type = GFC_SS_TEMP;
       loop->temp_ss->data.temp.type =
 	gfc_get_element_type (TREE_TYPE (dest->data.info.descriptor));
-      loop->temp_ss->string_length = NULL_TREE;
+      loop->temp_ss->string_length = dest->string_length;
       loop->temp_ss->data.temp.dimen = loop->dimen;
       loop->temp_ss->next = gfc_ss_terminator;
       gfc_add_ss_to_loop (loop, loop->temp_ss);
@@ -3617,6 +3617,7 @@ gfc_conv_expr_descriptor (gfc_se * se, gfc_expr * expr, gfc_ss * ss)
       loop.temp_ss->type = GFC_SS_TEMP;
       loop.temp_ss->next = gfc_ss_terminator;
       loop.temp_ss->data.temp.type = gfc_typenode_for_spec (&expr->ts);
+
       /* ... which can hold our string, if present.  */
       if (expr->ts.type == BT_CHARACTER)
 	se->string_length = loop.temp_ss->string_length

gcc/fortran/trans-expr.c

@@ -356,27 +356,40 @@ gfc_conv_variable (gfc_se * se, gfc_expr * expr)
 	  return;
 	}
 
-      /* Dereference scalar dummy variables.  */
-      if (sym->attr.dummy
-	  && sym->ts.type != BT_CHARACTER
-	  && !sym->attr.dimension)
+
+      /* Dereference the expression, where needed. Since characters
+	 are entirely different from other types, they are treated 
+	 separately.  */
+      if (sym->ts.type == BT_CHARACTER)
+	{
+          /* Dereference character pointer dummy arguments
+	     or results.  */
+	  if ((sym->attr.pointer || sym->attr.allocatable)
+	      && ((sym->attr.dummy)
+		  || (sym->attr.function
+		  || sym->attr.result)))
+	    se->expr = gfc_build_indirect_ref (se->expr);
+	}
+      else
+	{
+          /* Dereference non-charcter scalar dummy arguments.  */
+	  if ((sym->attr.dummy) && (!sym->attr.dimension))
 	    se->expr = gfc_build_indirect_ref (se->expr);
 
           /* Dereference scalar hidden result.  */
-      if (gfc_option.flag_f2c 
+	  if ((gfc_option.flag_f2c && sym->ts.type == BT_COMPLEX)
 	      && (sym->attr.function || sym->attr.result)
-	  && sym->ts.type == BT_COMPLEX
-	  && !sym->attr.dimension)
+	      && (!sym->attr.dimension))
 	    se->expr = gfc_build_indirect_ref (se->expr);
 
-      /* Dereference pointer variables.  */
+          /* Dereference non-character pointer variables. 
+	     These must be dummys or results or scalars.  */
 	  if ((sym->attr.pointer || sym->attr.allocatable)
-	  && (sym->attr.dummy
-	      || sym->attr.result
-	      || sym->attr.function
-	      || !sym->attr.dimension)
-          && sym->ts.type != BT_CHARACTER)
+	      && ((sym->attr.dummy) 
+		  || (sym->attr.function || sym->attr.result)
+		  || (!sym->attr.dimension)))
 	    se->expr = gfc_build_indirect_ref (se->expr);
+	}
 
       ref = expr->ref;
     }
@@ -1083,6 +1096,15 @@ gfc_conv_function_call (gfc_se * se, gfc_symbol * sym,
   var = NULL_TREE;
   len = NULL_TREE;
 
+  /* Obtain the string length now because it is needed often below.  */
+  if (sym->ts.type == BT_CHARACTER)
+    {
+      gcc_assert (sym->ts.cl && sym->ts.cl->length
+		  && sym->ts.cl->length->expr_type == EXPR_CONSTANT);
+      len = gfc_conv_mpz_to_tree
+	      (sym->ts.cl->length->value.integer, sym->ts.cl->length->ts.kind);
+    }
+
   if (se->ss != NULL)
     {
       if (!sym->attr.elemental)
@@ -1097,6 +1119,9 @@ gfc_conv_function_call (gfc_se * se, gfc_symbol * sym,
               /* Access the previously obtained result.  */
               gfc_conv_tmp_array_ref (se);
               gfc_advance_se_ss_chain (se);
+
+	      /* Bundle in the string length.  */
+	      se->string_length=len;
               return;
             }
 	}
@@ -1109,13 +1134,25 @@ gfc_conv_function_call (gfc_se * se, gfc_symbol * sym,
   if (byref)
     {
       if (se->direct_byref) 
+	{
 	  arglist = gfc_chainon_list (arglist, se->expr);
+
+	  /* Add string length to argument list.  */
+	  if (sym->ts.type == BT_CHARACTER)
+	    {
+	      sym->ts.cl->backend_decl = len;
+	      arglist = gfc_chainon_list (arglist, 
+				convert (gfc_charlen_type_node, len));
+	    }
+	}
       else if (sym->result->attr.dimension)
 	{
 	  gcc_assert (se->loop && se->ss);
+
 	  /* Set the type of the array.  */
 	  tmp = gfc_typenode_for_spec (&sym->ts);
 	  info->dimen = se->loop->dimen;
+
 	  /* Allocate a temporary to store the result.  */
 	  gfc_trans_allocate_temp_array (se->loop, info, tmp);
 
@@ -1124,22 +1161,46 @@ gfc_conv_function_call (gfc_se * se, gfc_symbol * sym,
 	    gfc_conv_descriptor_stride (info->descriptor, gfc_rank_cst[0]);
 	  gfc_add_modify_expr (&se->pre, tmp,
 			       convert (TREE_TYPE (tmp), integer_zero_node));
+
 	  /* Pass the temporary as the first argument.  */
 	  tmp = info->descriptor;
 	  tmp = gfc_build_addr_expr (NULL, tmp);
 	  arglist = gfc_chainon_list (arglist, tmp);
+
+	  /* Add string length to argument list.  */
+	  if (sym->ts.type == BT_CHARACTER)
+	    {
+	      sym->ts.cl->backend_decl = len;
+	      arglist = gfc_chainon_list (arglist, 
+			      convert (gfc_charlen_type_node, len));
+	    }
+
 	}
       else if (sym->ts.type == BT_CHARACTER)
 	{
-	  gcc_assert (sym->ts.cl && sym->ts.cl->length
-		  && sym->ts.cl->length->expr_type == EXPR_CONSTANT);
-	  len = gfc_conv_mpz_to_tree
-	    (sym->ts.cl->length->value.integer, sym->ts.cl->length->ts.kind);
+
+	  /* Pass the string length.  */
 	  sym->ts.cl->backend_decl = len;
 	  type = gfc_get_character_type (sym->ts.kind, sym->ts.cl);
 	  type = build_pointer_type (type);
 
+	  /* Return an address to a char[4]* temporary for character pointers.  */
+	  if (sym->attr.pointer || sym->attr.allocatable)
+	    {
+	      /* Build char[4] * pstr.  */
+	      tmp = fold_build2 (MINUS_EXPR, gfc_charlen_type_node, len,
+				 convert (gfc_charlen_type_node, integer_one_node));
+	      tmp = build_range_type (gfc_array_index_type, gfc_index_zero_node, tmp);
+	      tmp = build_array_type (gfc_character1_type_node, tmp);
+	      var = gfc_create_var (build_pointer_type (tmp), "pstr");
+
+	      /* Provide an address expression for the function arguments.  */
+	      var = gfc_build_addr_expr (NULL, var);
+	    }
+	  else
+	    {
 	      var = gfc_conv_string_tmp (se, type, len);
+	    }
 	  arglist = gfc_chainon_list (arglist, var);
 	  arglist = gfc_chainon_list (arglist, 
 				      convert (gfc_charlen_type_node, len));
@@ -1299,10 +1360,17 @@ gfc_conv_function_call (gfc_se * se, gfc_symbol * sym,
 		  gfc_trans_runtime_check (tmp, gfc_strconst_fault, &se->pre);
 		}
 	      se->expr = info->descriptor;
+	      /* Bundle in the string length.  */
+	      se->string_length = len;
 	    }
 	  else if (sym->ts.type == BT_CHARACTER)
 	    {
+	      /* Dereference for character pointer results.  */
+	      if (sym->attr.pointer || sym->attr.allocatable)
+		se->expr = gfc_build_indirect_ref (var);
+	      else
 	        se->expr = var;
+
 	      se->string_length = len;
 	    }
 	  else