Add support for DWARF-5 and experimental two-level line number tables.

Add support for DWARF-5 and experimental two-level line number tables.

2014-12-23  Cary Coutant  <ccoutant@google.com>

gas/
	* config/obj-elf.c (elf_pseudo_table): Add .lloc and .subprog
	directives.
	* dwarf2dbg.h (struct dwarf2_line_info): Add logical field.
	(dwarf2_directive_subprog): New function.
	(dwarf2_directive_loc): Add is_lloc parameter.
	* dwarf2dbg.c: Include "hash.h".
	(DWARF2_LINE_EXPERIMENTAL_VERSION): New macro.
	(DWARF2_EXPERIMENTAL_LINE_OPCODE_BASE): New macro.
	(opcode_base): New static variable.
	(DWARF2_LINE_BASE, DWARF2_LINE_RANGE): Adjust parameters.
	(DWARF2_LINE_MAX_OPS_PER_INSN): New macro.
	(SPECIAL_LINE, SPECIAL_ADDR): Use opcode_base.
	(struct subprog_entry): New struct.
	(subprogs, subprogs_in_use, subprogs_allocated): New variables.
	(struct logicals_entry): New struct.
	(logicals, logicals_in_use, logicals_allocated, logicals_with_labels):
	New variables.
	(struct string_table): New struct.
	(debug_line_str_table): New variable.
	(current): Add logical field.
	(dwarf2_gen_line_info): Fill in symbol and segment for recent logicals.
	(dwarf2_where): Add logical field.
	(make_subprog_entry): New function.
	(make_logical): New function.
	(dwarf2_directive_subprog): New function.
	(dwarf2_directive_loc): Add is_lloc parameter; add support for .lloc
	directive.
	(out_set_addr_from_logical): New function.
	(size_inc_line_addr): Fix signed/unsigned warnings. Use opcode_base.
	(emit_inc_line_addr): Likewise.
	(emit_logicals): New function.
	(process_entries): Add support for two-level line tables.
	(add_to_string_table): New function.
	(out_string_table): New function.
	(out_dwarf5_file_list): New function.
	(out_subprog_list): New function.
	(out_debug_line): Add support for DWARF-5 line tables and for
	experimental two-level line number tables.
	(dwarf2_finish): Likewise.