[lto] tree.c (build_function_type_list): Don't allocate a temporary vector.

[Kazu Hirata]

Hi,

Attached is a patch to reduce memory usage in
build_function_type_list.

build_function_type_list builds a parameter type list based on
parameters given in "...".

Without this patch, build_function_type_list temporarily allocates a
vector on heap to store all parameters given in "...".  This patch
eliminates the temporary storage by iterating the variable argument
list twice -- once to figure out the length and once to populate the
parameter type list.

Tested on x86_64-pc-linux-gnu.  Committed to the LTO branch.

Kazu Hirata

2006-08-09  Kazu Hirata  <kazu@codesourcery.com>

	* tree.c (build_function_type_list): Don't allocate a
	temporary vector.

Index: tree.c
===================================================================
*** tree.c	(revision 116006)
--- tree.c	(working copy)
*************** build_function_type (tree value_type, tr
*** 5277,5300 ****
  tree
  build_function_type_list (tree return_type, ...)
  {
!   tree t, args;
!   VEC(tree,heap) *v = NULL;
    va_list p;
  
    va_start (p, return_type);
- 
    for (t = va_arg (p, tree); t != NULL_TREE; t = va_arg (p, tree))
!     VEC_safe_push (tree, heap, v, t);
! 
!   VEC_safe_push (tree, heap, v, void_type_node);
! 
!   args = vec_heap2parm_types (v);
!   VEC_free (tree, heap, v);
  
!   args = build_function_type (return_type, args);
  
    va_end (p);
!   return args;
  }
  
  /* Build a METHOD_TYPE for a member of BASETYPE.  The RETTYPE (a TYPE)
--- 5277,5303 ----
  tree
  build_function_type_list (tree return_type, ...)
  {
!   tree t, parm_types;
    va_list p;
+   int len = 0;
+   int i;
  
+   /* Determine the length of the parameter list.  */
    va_start (p, return_type);
    for (t = va_arg (p, tree); t != NULL_TREE; t = va_arg (p, tree))
!     len++;
!   va_end (p);
  
!   /* We add one because we are going to append void_type_node.  */
!   parm_types = alloc_parm_types (len + 1);
  
+   va_start (p, return_type);
+   for (i = 0; i < len; i++)
+     *(nth_parm_type_ptr (parm_types, i)) = va_arg (p, tree);
+   *(nth_parm_type_ptr (parm_types, i)) = void_type_node;
    va_end (p);
! 
!   return build_function_type (return_type, parm_types);
  }
  
  /* Build a METHOD_TYPE for a member of BASETYPE.  The RETTYPE (a TYPE)