backport: re PR debug/48190 ([regression?] Huge memory use while compiling qemu-0...

backport: re PR debug/48190 ([regression?] Huge memory use while compiling qemu-0.4.0)

gcc/
	Backport from mainline:

	2011-03-29  Richard Sandiford  <richard.sandiford@linaro.org>

	PR debug/48190
	* dwarf2out.c (dw_loc_list_node): Add resolved_addr and replaced.
	(cached_dw_loc_list_def): New structure.
	(cached_dw_loc_list): New typedef.
	(cached_dw_loc_list_table): New variable.
	(cached_dw_loc_list_table_hash): New function.
	(cached_dw_loc_list_table_eq): Likewise.
	(add_location_or_const_value_attribute): Take a bool cache_p.
	Cache the list when the parameter is true.
	(gen_formal_parameter_die): Update caller.
	(gen_variable_die): Likewise.
	(dwarf2out_finish): Likewise.
	(dwarf2out_abstract_function): Nullify cached_dw_loc_list_table
	while generating debug info for the decl.
	(dwarf2out_function_decl): Clear cached_dw_loc_list_table.
	(dwarf2out_init): Initialize cached_dw_loc_list_table.
	(resolve_addr): Cache the result of resolving a chain of
	location lists.

	From: 2010-10-12  Jakub Jelinek  <jakub@redhat.com>
	* dwarf2out.c (dw_loc_list_node): Add emitted field.
	(output_loc_list): Return immediately if emitted is set, set it.

From-SVN: r181717