Special-case tree_decl/tree_list allocations.

Special-case tree_decl/tree_list allocations.

	* ggc-page.c (OBJECT_PER_PAGE): Reimplement.
	(OBJECT_SIZE): New macro.
	(NUM_EXTRA_ORDER): Likewise.
	(extra_order_size_table): New variable.
	(NUM_ORDERS): New macro.
	(objects_per_page_table): New variable.
	(object_size_table): New variable.
	(G.pages): Use NUM_ORDERS to bound the array.
	(G.page_tails): Likewise.
	(DIV_ROUND_UP): Remove.
	(BITMAP_SIZE): Use CEIL, instead of DIV_ROUND_UP.
	(alloc_page): Use OBJECT_SIZE.
	(size_lookup): Don't make it const.
	(ggc_alloc): Use OBJECT_SIZE.
	(ggc_set_mark): Likewise.
	(ggc_get_size): Likewise.
	(init_ggc): Set up the object_size_table, objects_per_page_table,
	and adjust size_lookup.
	(ggc_recalculate_in_use_p): Use CEIL, not DIV_ROUND_UP.
	(ggc_pop_context): Use NUM_ORDERS.
	(clear_marks): Likewise.
	(sweep_pages): Likewise.
	(poison_pages): Likewise.
	(ggc_print_statistics): Use OBJECT_SIZE.

From-SVN: r38692