dwarf2out.c: For DWARF 4+, output DW_AT_high_pc as constant offset.

dwarf2out.c: For DWARF 4+, output DW_AT_high_pc as constant offset.

        * dwarf2out.h (enum dw_val_class): Add dw_val_class_high_pc.
        * dwarf2out.c (dw_val_equal_p): Handle dw_val_class_high_pc.
        (add_AT_low_high_pc): New function.
        (AT_lbl): Handle dw_val_class_high_pc.
        (print_die): Likewise.
        (attr_checksum): Likewise.
        (attr_checksum_ordered): Likewise.
        (same_dw_val_p): Likewise.
        (size_of_die): Likewise.
        (value_format): Likewise.
        (output_die): Likewise.
        (gen_subprogram_die): Use add_AT_low_high_pc.
        (add_high_low_attributes): Likewise.
        (dwarf2out_finish): Likewise.

From-SVN: r190543