* lto-streamer-out.c (lto_string_index): break out from...; offset by 1
so 0 means NULL string.
(lto_output_string_with_length): ... here.
(lto_output_string, output_string_cst, output_identifier): Update handling
of NULL strings.
(lto_output_location_bitpack): New function.
(lto_output_location): Use it.
(lto_output_tree_ref): Use output_record_start.
(pack_ts_type_common_value_fields): Pack aliagn & alias set in var len values.
* lto-streamer-in.c (string_for_index): Break out from ...; offset values by 1.
(input_string_internal): ... here;
(input_string_cst, input_identifier, lto_input_string): Update handling of
NULL strings.
(lto_input_location_bitpack): New function
(lto_input_location): Use it.
(unpack_ts_type_common_value_fields): Pack align & alias in var len values.
* lto-streamer.h (bp_pack_val_len_unsigned, bp_pack_val_len_int,
bp_unpack_val_len_unsigned, bp_unpack_val_len_int): Declare.
(bp_pack_value): Sanity check the value range.
* lto-section-in.c (bp_unpack_val_len_unsigned, bp_unpack_val_len_int):
New functions.
* lto-section-out.h (bp_pack_val_len_unsigned, bp_pack_val_len_int):
New functions.
From-SVN: r174325
