Initial support for Fission. http://gcc.gnu.org/wiki/DebugFission

	Initial support for Fission.  gcc.gnu.org/wiki/DebugFission
	* symfile.c (default_symfile_relocate): Use sectp->owner instead of
	objfile->obfd.
	* symfile.h (dwarf2_debug_sections): New member addr.
	* dwarf2expr.c (execute_stack_op): New case DW_OP_GNU_addr_index.
	(ctx_no_get_addr_index): New function.
	* dwarf2expr.h (dwarf_expr_context_funcs): New member get_addr_index.
	(ctx_no_get_addr_index): Declare.
	* dwarf2-frame.c (dwarf2_frame_ctx_funcs): Update.
	* dwarf2loc.c (dwarf_expr_get_addr_index): New function.
	(dwarf_expr_ctx_funcs): Update.
	(needs_get_addr_index): New function.
	(needs_frame_ctx_funcs): Update.
	* dwarf2loc.h (dwarf2_read_addr_index): Declare.
	* dwarf2read.c: #include "gdbcore.h".
	(dwarf2_per_objfile): New members addr, dwo_files.
	(dwarf2_elf_names): Add entry for addr.
	(struct dwo_section_names): New type.
	(dwo_section_names): New static global.
	(dwarf2_cu): New members dwo_unit, addr_base, have_addr_base.
	(dwarf2_per_cu_data): New member is_debug_types, all boolean uses of
	old debug_types_section member updated to use this.
	Rename member debug_types_section to info_or_types_section,
	all uses updated.
	(signatured_type): Rename member type_offset to type_offset_in_tu,
	all uses updated.  New member type_offset_in_section.
	(struct dwo_sections): New type.
	(struct dwo_unit): New type.
	(struct dwo_file): New type.
	(die_reader_specs): New member dwo_file.
	(dwarf2_locate_sections): Watch for .debug_addr.
	(zlib_decompress_section): Use sectp->owner instead of objfile->obfd.
	(dwarf2_read_section): Get bfd of section from bfd's asection,
	instead of objfile.
	(create_cus_from_index): Initialize the_cu->info_or_types_section.
	(create_signatured_type_table_from_index): Initialize
	sig_type->info_or_types_section.
	(dw2_get_file_names): Statement lists for type units with DWO files
	live in the DWO file.
	(create_debug_types_hash_table): New function.
	(create_all_type_units): Rewrite.
	(init_cu_die_reader): New arg dwo_file, all callers updated.
	(init_and_read_dies_worker): Get section from
	this_cu->info_or_types_section.  Set sig_type->type_offset_in_section.
	Watch for DW_AT_GNU_dwo_name and if present lookup the file and
	continue reading the CU/TU from there.
	(init_cutu_and_read_dies_no_follow): New arg dwo_file, all callers
	updated.  Get section from this_cu->info_or_types_section.
	(create_all_comp_units): Initialize this_cu->info_or_types_section.
	(skip_one_die): New cases DW_FORM_GNU_addr_index,
	DW_FORM_GNU_str_index.
	(hash_dwo_file, eq_dwo_file): New functions.
	(allocate_dwo_file_hash_table): New function.
	(hash_dwo_unit, eq_dwo_unit): New functions.
	(allocate_dwo_unit_table): New function.
	(dwarf2_locate_dwo_sections): New function.
	(struct create_dwo_info_table_data): New type.
	(create_debug_info_hash_table_reader): New function.
	(create_debug_info_hash_table): New function.
	(try_open_dwo_file, open_dwo_file, init_dwo_file): New function.
	(lookup_dwo_file): New function.
	(lookup_dwo_comp_unit, lookup_dwo_type_unit): New functions.
	(free_dwo_file, free_dwo_file_cleanup): New functions.
	(free_dwo_file_from_slot, free_dwo_files): New functions.
	(dwarf2_get_pc_bounds): Handle DW_FORM_GNU_addr_index.
	(dwarf2_record_block_ranges): Ditto.
	(read_partial_die): Ditto.
	(process_enumeration_scope): Update to use type_offset_in_section.
	(read_full_die_1): New function.
	(read_full_die): Rewrite.
	(read_attribute_value): New cases DW_FORM_GNU_addr_index,
	DW_FORM_GNU_str_index.
	(read_addr_index_1, read_addr_index): New functions.
	(read_addr_index_from_leb128): New function.
	(struct dwarf2_read_addr_index_data): New type.
	(dwarf2_read_addr_index_reader): New function.
	(dwarf2_read_addr_index): New function.
	(read_str_index): New function.
	(leb128_size): New function.
	(dwarf_decode_line_header): Delete arg abfd, all callers updated.
	If processing a type unit from a DWO file, get the line section
	from the DWO file.
	(var_decode_location): Watch for DW_OP_GNU_addr_index.
	(dwarf2_const_value_attr): New cases DW_FORM_GNU_addr_index,
	DW_FORM_GNU_str_index.
	(lookup_die_type): Check whether section offset of type's die is
	known before looking it up.  Remove assert.  Condition can
	legimately happen for inter-cu type references.
	(dwarf_attr_name): Handle Fission attributes.
	(dwarf_form_name): Handle Fission forms.
	(dump_die_shallow): New cases DW_FORM_GNU_addr_index,
	DW_FORM_GNU_str_index.
	(follow_die_sig): Update to use type_offset_in_section.
	(decode_locdesc): New case DW_OP_GNU_addr_index.
	(skip_form_bytes): New cases DW_FORM_GNU_addr_index,
	DW_FORM_GNU_str_index.
	(cu_debug_loc_section): New function.
	(fill_in_loclist_baton, dwarf2_symbol_mark_computed): Call it.
	(dwarf2_per_objfile_free): Unmap .debug_addr section.
	Free DWO files if present.
	* xcoffread.c (dwarf2_xcoff_names): Add .debug_addr.

	testsuite/
	* gdb.dwarf2/dw2-intercu.S (.Ltype_int2_in_cu2): Renamed from
	.Ltype_int_in_cu2.  Use name "int2" instead of "int".
	All uses updated.
	* gdb.dwarf2/dw2-intercu.exp: Add "ptype int2" ahead of
	"ptype func_cu1" to expand cu2 before cu1.