Remove memory leak in handle_vector_size_attribute

[Bernd Schmidt]

While debugging some other altivec problems, I noticed that we create a
new type node each time handle_vector_size_attribute is called.  This
patch plugs that memory leak.

Bootstrapped on i686-linux, and tested against ppc-eabisimaltivec.  Two
altivec tests seem to have execution failures with or without the patch.


Bernd

	* attribs.c (vector_type_node_list): New static variable.
	(handle_vector_size_attribute): Use it to avoid generating a
	new type node each time we are called.

Index: attribs.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/attribs.c,v
retrieving revision 1.20
diff -c -p -r1.20 attribs.c
*** attribs.c	29 Mar 2002 21:45:56 -0000	1.20
--- attribs.c	17 Apr 2002 18:21:51 -0000
*************** handle_deprecated_attribute (node, name,
*** 1268,1273 ****
--- 1268,1280 ----
    return NULL_TREE;
  }
  
+ /* Keep a list of vector type nodes we created in handle_vector_size_attribute,
+    to prevent us from duplicating type nodes unnecessarily.
+    The normal mechanism to prevent duplicates is to use type_hash_canon, but
+    since we want to distinguish types that are essentially identical (except
+    for their debug representation), we use a local list here.  */
+ static tree vector_type_node_list = 0;
+ 
  /* Handle a "vector_size" attribute; arguments as in
     struct attribute_spec.handler.  */
  
*************** handle_vector_size_attribute (node, name
*** 1281,1287 ****
  {
    unsigned HOST_WIDE_INT vecsize, nunits;
    enum machine_mode mode, orig_mode, new_mode;
!   tree type = *node, new_type;
  
    *no_add_attrs = true;
  
--- 1288,1295 ----
  {
    unsigned HOST_WIDE_INT vecsize, nunits;
    enum machine_mode mode, orig_mode, new_mode;
!   tree type = *node, new_type = NULL_TREE;
!   tree type_list_node;
  
    *no_add_attrs = true;
  
*************** handle_vector_size_attribute (node, name
*** 1337,1347 ****
  	break;
        }
  
!   if (new_mode == VOIDmode)
!     error ("no vector mode with the size and type specified could be found");
!   else
      {
!       tree index, array, rt;
  
        new_type = (*lang_hooks.types.type_for_mode) (new_mode,
  						    TREE_UNSIGNED (type));
--- 1345,1378 ----
  	break;
        }
  
!     if (new_mode == VOIDmode)
      {
!       error ("no vector mode with the size and type specified could be found");
!       return NULL_TREE;
!     }
! 
!   for (type_list_node = vector_type_node_list; type_list_node;
!        type_list_node = TREE_CHAIN (type_list_node))
!     {
!       tree other_type = TREE_VALUE (type_list_node);
!       tree record = TYPE_DEBUG_REPRESENTATION_TYPE (other_type);
!       tree fields = TYPE_FIELDS (record);
!       tree field_type = TREE_TYPE (fields);
!       tree array_type = TREE_TYPE (field_type);
!       if (TREE_CODE (fields) != FIELD_DECL
! 	  || TREE_CODE (field_type) != ARRAY_TYPE)
! 	abort ();
! 
!       if (TYPE_MODE (other_type) == mode && type == array_type)
! 	{
! 	  new_type = other_type;
! 	  break;
! 	}
!     }
! 
!   if (new_type == NULL_TREE)
!     {
!       tree index, array, rt, list_node;
  
        new_type = (*lang_hooks.types.type_for_mode) (new_mode,
  						    TREE_UNSIGNED (type));
*************** handle_vector_size_attribute (node, name
*** 1367,1376 ****
        layout_type (rt);
        TYPE_DEBUG_REPRESENTATION_TYPE (new_type) = rt;
  
!       /* Build back pointers if needed.  */
!       *node = vector_size_helper (*node, new_type);
      }
!     
    return NULL_TREE;
  }
  
--- 1398,1411 ----
        layout_type (rt);
        TYPE_DEBUG_REPRESENTATION_TYPE (new_type) = rt;
  
!       list_node = build_tree_list (NULL, new_type);
!       TREE_CHAIN (list_node) = vector_type_node_list;
!       vector_type_node_list = list_node;
      }
! 
!   /* Build back pointers if needed.  */
!   *node = vector_size_helper (*node, new_type);
! 
    return NULL_TREE;
  }