[Patch]c-decl.c: avoid linear search of all decls

["Turly O'Connor" <turly at apple dot com>]

Hey there,

This patch alters c-decl.c to maintain a _list_ of the incomplete
declarations requiring later "filling in", rather than just keeping
a count of incomplete decls and then searching ALL decls.  This
can result in parse speed improvements for compilations with a
large number of decls.  YMMV.

Bootstraps and doesn't alter testsuite results.

Have Fun!

--turly

2001-03-13  Turly O'Connor <turly@apple.com>
	* c-decl.c (struct binding_level): Replace "int n_incomplete" with
	"tree incomplete_list" to keep tabs on incomplete structs/unions.
  	(pushdecl): Populate the list if required.
	(mark_binding_level): GC the list.
	(finish_struct): Search incomplete_list rather than all decls.


Index: c-decl.c
===================================================================
RCS file: /cvs/repository/CoreTools/gcc3/gcc/c-decl.c,v
retrieving revision 1.1.1.6
diff -p -r1.1.1.6 c-decl.c
*** c-decl.c	2001/03/07 02:45:15	1.1.1.6
--- c-decl.c	2001/03/13 23:38:45
*************** struct binding_level
*** 210,218 ****
       /* Nonzero means make a BLOCK if this level has any subblocks.  */
       char keep_if_subblocks;

!     /* Number of decls in `names' that have incomplete
          structure or union types.  */
!     int n_incomplete;

       /* A list of decls giving the (reversed) specified order of parms,
          not including any forward-decls in the parmlist.
--- 210,218 ----
       /* Nonzero means make a BLOCK if this level has any subblocks.  */
       char keep_if_subblocks;

!     /* List of decls in `names' that have incomplete
          structure or union types.  */
!     tree incomplete_list;

       /* A list of decls giving the (reversed) specified order of parms,
          not including any forward-decls in the parmlist.
*************** static struct binding_level *global_bind
*** 239,245 ****
   /* Binding level structures are initialized by copying this one.  */

   static struct binding_level clear_binding_level
!   = {NULL, NULL, NULL, NULL, NULL, NULL_BINDING_LEVEL, 0, 0, 0, 0, 0, 
0,
        NULL};

   /* Nonzero means unconditionally make a BLOCK for the next level 
pushed.  */
--- 239,245 ----
   /* Binding level structures are initialized by copying this one.  */

   static struct binding_level clear_binding_level
!   = {NULL, NULL, NULL, NULL, NULL, NULL_BINDING_LEVEL, 0, 0, 0, 0, 0, 
NULL,
        NULL};

   /* Nonzero means unconditionally make a BLOCK for the next level 
pushed.  */
*************** pushdecl (x)
*** 2476,2488 ****
   	    b->shadowed = tree_cons (name, oldlocal, b->shadowed);
   	}

!       /* Keep count of variables in this level with incomplete type.
   	 If the input is erroneous, we can have error_mark in the type
   	 slot (e.g. "f(void a, ...)") - that doesn't count as an
   	 incomplete type.  */
         if (TREE_TYPE (x) != error_mark_node
   	  && !COMPLETE_TYPE_P (TREE_TYPE (x)))
! 	++b->n_incomplete;
       }

     /* Put decls on list in reverse order.
--- 2476,2488 ----
   	    b->shadowed = tree_cons (name, oldlocal, b->shadowed);
   	}

!       /* Keep list of variables in this level with incomplete type.
   	 If the input is erroneous, we can have error_mark in the type
   	 slot (e.g. "f(void a, ...)") - that doesn't count as an
   	 incomplete type.  */
         if (TREE_TYPE (x) != error_mark_node
   	  && !COMPLETE_TYPE_P (TREE_TYPE (x)))
! 	  b->incomplete_list = tree_cons (NULL_TREE, x, b->incomplete_list);
       }

     /* Put decls on list in reverse order.
*************** mark_binding_level (arg)
*** 2962,2967 ****
--- 2962,2968 ----
         ggc_mark_tree (level->blocks);
         ggc_mark_tree (level->this_block);
         ggc_mark_tree (level->parm_order);
+       ggc_mark_tree (level->incomplete_list);
       }
   }

*************** finish_struct (t, fieldlist, attributes)
*** 5492,5512 ****
     /* If this structure or union completes the type of any previous
        variable declaration, lay it out and output its rtl.  */

!   if (current_binding_level->n_incomplete != 0)
       {
!       tree decl;
!       for (decl = current_binding_level->names; decl; decl = 
TREE_CHAIN (decl))
! 	{
   	  if (TYPE_MAIN_VARIANT (TREE_TYPE (decl)) == TYPE_MAIN_VARIANT (t)
   	      && TREE_CODE (decl) != TYPE_DECL)
   	    {
   	      layout_decl (decl, 0);
! 	      /* This is a no-op in c-lang.c or something real in 
objc-actions.c.  */
   	      maybe_objc_check_decl (decl);
   	      rest_of_decl_compilation (decl, NULL_PTR, toplevel, 0);
   	      if (! toplevel)
   		expand_decl (decl);
! 	      --current_binding_level->n_incomplete;
   	    }
   	  else if (!COMPLETE_TYPE_P (TREE_TYPE (decl))
   		   && TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
--- 5493,5521 ----
     /* If this structure or union completes the type of any previous
        variable declaration, lay it out and output its rtl.  */

!   if (current_binding_level->incomplete_list != NULL_TREE)
       {
!       tree prev = NULL_TREE;
!
!       for (x = current_binding_level->incomplete_list; x; x = 
TREE_CHAIN (x))
!         {
! 	  tree decl = TREE_VALUE (x);
!
   	  if (TYPE_MAIN_VARIANT (TREE_TYPE (decl)) == TYPE_MAIN_VARIANT (t)
   	      && TREE_CODE (decl) != TYPE_DECL)
   	    {
   	      layout_decl (decl, 0);
! 	      /* This is a no-op in c-lang.c or real code in objc-act.c.  */
   	      maybe_objc_check_decl (decl);
   	      rest_of_decl_compilation (decl, NULL_PTR, toplevel, 0);
   	      if (! toplevel)
   		expand_decl (decl);
!
! 	      /* Unlink X from the incomplete list.  */
! 	      if (prev)
! 		TREE_CHAIN (prev) = TREE_CHAIN (x);
! 	      else
! 	        current_binding_level->incomplete_list = TREE_CHAIN (x);
   	    }
   	  else if (!COMPLETE_TYPE_P (TREE_TYPE (decl))
   		   && TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)