Remove dwarf2_per_objfile global

Remove dwarf2_per_objfile global

This patch removes the global variable dwarf2_per_objfile.  This global
variable is set at the various entry points of dwarf2read.c (using
dw2_setup), and is referred to throughout the file.  Instead of passing
data between functions in global variables like this one, it would be
better if the functions that depend on it either received it as argument
or got it from the existing arguments they receive.  For example, a
function receiving a reference to a dwarf2_per_cu_data can access it
from dwarf2_per_cu_data::dwarf2_per_objfile.

This patch has been tested on the buildbot.

gdb/ChangeLog:

	* dwarf2read.c (struct mapped_debug_names): Add constructor.
	<dwarf2_per_objfile>: New field.
	(dwarf2_per_objfile): Remove global.
	(get_dwarf2_per_objfile): New function.
	(set_dwarf2_per_objfile): New function.
	(dwarf2_build_psymtabs_hard): Change objfile parameter to
	dwarf2_per_objfile.
	(abbrev_table_read_table): Add dwarf2_per_objfile parameter.
	(read_abbrev_offset): Likewise.
	(read_indirect_string): Likewise.
	(read_indirect_line_string): Likewise.
	(read_indirect_string_at_offset): Likewise.
	(read_indirect_string_from_dwz): Likewise.
	(dwarf2_find_containing_comp_unit): Change objfile parameter to
	dwarf2_per_objfile.
	(age_cached_comp_units): Add dwarf2_per_objfile parameter.
	(create_all_comp_units): Change objfile parameter to
	dwarf2_per_objfile.
	(create_all_type_units): Likewise.
	(process_queue): Add dwarf2_per_objfile parameter.
	(read_and_check_comp_unit_head): Likewise.
	(lookup_dwo_unit_in_dwp): Likewise.
	(get_dwp_file): Likewise.
	(process_cu_includes): Likewise.
	(struct free_dwo_file_cleanup_data): New struct.
	(dwarf2_has_info): Use get_dwarf2_per_objfile and
	set_dwarf2_per_objfile.
	(dwarf2_get_dwz_file): Add dwarf2_per_objfile parameter.
	(dw2_do_instantiate_symtab): Get dwarf2_per_objfile from
	context, adjust calls.
	(dw2_instantiate_symtab): Likewise.
	(dw2_get_cutu): Add dwarf2_per_objfile parameter.
	(dw2_get_cu): Likewise.
	(create_cu_from_index_list): Change objfile parameter to
	dwarf2_per_objfile.
	(create_cus_from_index_list): Get dwarf2_per_objfile from
	context, adjust calls.
	(create_cus_from_index): Likewise.
	(create_signatured_type_table_from_index): Change objfile
	parameter to dwarf2_per_objfile.
	(create_signatured_type_table_from_debug_names): Change objfile
	parameter to dwarf2_per_objfile.
	(create_addrmap_from_index): Likewise.
	(create_addrmap_from_aranges): Likewise.
	(dwarf2_read_index): Use get_dwarf2_per_objfile, adjust calls.
	(dw2_setup): Remove.
	(dw2_get_file_names_reader): Get dwarf2_per_objfile from
	context.
	(dw2_find_last_source_symtab): Get dwarf2_per_objfile using
	get_dwarf2_per_objfile.
	(dw2_forget_cached_source_info): Likewise.
	(dw2_map_symtabs_matching_filename): Likewise.
	(struct dw2_symtab_iterator) <index>: Remove.
	<dwarf2_per_objfile>: New field.
	(dw2_symtab_iter_init): Replace index parameter with
	dwarf2_per_objfile.
	(dw2_symtab_iter_next): Use dwarf2_per_objfile from iter.
	(dw2_lookup_symbol): Use get_dwarf2_per_objfile and adjust.
	(dw2_print_stats): Likewise.
	(dw2_dump): Likewise.
	(dw2_expand_symtabs_for_function): Likewise.
	(dw2_expand_all_symtabs): Likewise.
	(dw2_expand_symtabs_with_fullname): Likewise.
	(dw2_expand_marked_cus): Replace index and objfile parameters
	with dwarf2_per_objfile.
	(dw_expand_symtabs_matching_file_matcher): Add
	dwarf2_per_objfile parameter and adjust calls.
	(dw2_expand_symtabs_matching): Use get_dwarf2_per_objfile and
	adjust calls.
	(dw2_find_pc_sect_compunit_symtab): Don't call dw2_setup.
	(dw2_map_symbol_filenames): Use get_dwarf2_per_objfile and
	adjust calls.
	(create_cus_from_debug_names_list): Replace objfile parameter
	with dwarf2_per_objfile and adjust calls.
	(create_cus_from_debug_names): Likewise.
	(dwarf2_read_debug_names): Likewise.
	(mapped_debug_names::namei_to_name): Adjust call.
	(dw2_debug_names_iterator::next): Likewise.
	(dw2_debug_names_iterator::find_vec_in_debug_names): Likewise.
	(dw2_debug_names_lookup_symbol): Use get_dwarf2_per_objfile.
	(dw2_debug_names_dump): Likewise.
	(dw2_debug_names_expand_symtabs_for_function): Likewise.
	(dw2_debug_names_expand_symtabs_matching): Likewise.
	(dwarf2_initialize_objfile): Likewise.
	(dwarf2_build_psymtabs): Likewise.
	(get_abbrev_section_for_cu): Get dwarf2_per_objfile from
	this_cu.
	(error_check_comp_unit_head): Add dwarf2_per_objfile parameter.
	(read_and_check_comp_unit_head): Likewise.
	(read_abbrev_offset): Likewise.
	(create_debug_type_hash_table): Likewise.
	(create_debug_types_hash_table): Likewise.
	(create_all_type_units): Replace objfile parameter with
	dwarf2_per_objfile.
	(add_type_unit): Add dwarf2_per_objfile parameter.
	(fill_in_sig_entry_from_dwo_entry): Replace objfile parameter
	with dwarf2_per_objfile.
	(lookup_dwo_signatured_type): Get dwarf2_per_objfile from cu.
	(lookup_dwp_signatured_type): Likewise.
	(lookup_signatured_type): Likewise.
	(read_cutu_die_from_dwo): Likewise.
	(init_tu_and_read_dwo_dies): Likewise.
	(init_cutu_and_read_dies): Likewise.
	(init_cutu_and_read_dies_no_follow): Likewise.
	(allocate_type_unit_groups_table): Add objfile parameter.
	(create_type_unit_group): Use dwarf2_per_objfile from cu.
	(get_type_unit_group): Likewise.
	(process_psymtab_comp_unit): Update call.
	(build_type_psymtabs_reader): Use dwarf2_per_objfile from cu.
	(build_type_psymtabs_1): Add dwarf2_per_objfile parameter.
	(print_tu_stats): Likewise.
	(build_type_psymtab_dependencies): Use dwarf2_per_objfile passed
	in void* parameter.
	(build_type_psymtabs): Change objfile parameter to
	dwarf2_per_objfile.
	(process_skeletonless_type_unit): Use dwarf2_per_objfile
	passed in void* parameter.
	(process_skeletonless_type_units): Change objfile parameter to
	dwarf2_per_objfile.
	(set_partial_user): Likewise.
	(dwarf2_build_psymtabs_hard): Likewise.
	(read_comp_units_from_section): Likewise.
	(create_all_comp_units): Likewise.
	(scan_partial_symbols): Update calls.
	(add_partial_symbol): Likewise.
	(dwarf2_read_symtab): Use get_dwarf2_per_objfile.
	(maybe_queue_comp_unit): Use dwarf2_read_symtab from cu.
	(process_queue): Add dwarf2_per_objfile parameter.
	(get_compunit_symtab): Use dwarf2_per_objfile from cu.
	(compute_compunit_symtab_includes): Likewise.
	(process_cu_includes): Add dwarf2_per_objfile parameter.
	(process_full_comp_unit): Use dwarf2_per_objfile from cu.
	(process_full_type_unit): Likewise.
	(process_imported_unit_die): Update call.
	(handle_DW_AT_stmt_list): Use dwarf2_per_objfile from cu.
	(read_file_scope): Likewise.
	(allocate_dwo_file_hash_table): Add objfile parameter.
	(lookup_dwo_file_slot): Add dwarf2_per_objfile parameter.
	(create_cus_hash_table): Likewise.
	(create_dwp_hash_table): Likewise.
	(create_dwo_unit_in_dwp_v1): Likewise.
	(create_dwp_v2_section): Likewise.
	(create_dwo_unit_in_dwp_v2): Likewise.
	(lookup_dwo_unit_in_dwp): Likewise.
	(try_open_dwop_file): Likewise.
	(open_dwo_file): Likewise. Use dwarf2_per_objfile from cu.
	(open_and_init_dwo_file): Use dwarf2_per_objfile from cu, update
	cleanup to include a reference to dwarf2_per_objfile.
	(open_dwp_file): Add dwarf2_per_objfile parameter.
	(open_and_init_dwp_file): Likewise.
	(get_dwp_file): Likewise.
	(lookup_dwo_cutu): Use dwarf2_per_objfile from cu.
	(queue_and_load_all_dwo_tus): Update call.
	(free_dwo_file_cleanup): Use dwarf2_per_objfile from cleanup
	data.
	(dwarf2_rnglists_process): Use dwarf2_per_objfile from cu.
	(dwarf2_ranges_process): Likewise.
	(dwarf2_get_pc_bounds): Likewise.
	(mark_common_block_symbol_computed): Likewise.
	(abbrev_table_read_table): Add dwarf2_per_objfile parameter.
	(dwarf2_read_abbrevs): Update call.
	(read_partial_die): Use dwarf2_per_objfile from cu.
	(find_partial_die): Likewise.
	(fixup_partial_die): Likewise.
	(read_attribute_value): Likewise.
	(read_indirect_string_at_offset_from): Add objfile parameter.
	(read_indirect_string_at_offset): Add dwarf2_per_objfile
	parameter.
	(read_indirect_string_from_dwz): Add objfile parameter.
	(read_indirect_string): Add objfile parameter.
	(read_addr_index_1): Add dwarf2_per_objfile parameter.
	(read_addr_index): Use dwarf2_per_objfile from cu.
	(dwarf2_read_addr_index): Use dwarf2_per_objfile from cu, don't
	call dw2_setup.
	(read_str_index): Use dwarf2_per_objfile from cu.
	(get_debug_line_section): Likewise.
	(read_formatted_entries): Add dwarf2_per_objfile parameter.
	(dwarf_decode_line_header): Use dwarf2_per_objfile from cu.
	(new_symbol_full): Use dwarf2_per_objfile from cu.
	(build_error_marker_type): Likewise.
	(lookup_die_type): Likewise.
	(determine_prefix): Likewise.
	(follow_die_offset): Likewise.
	(dwarf2_fetch_die_loc_sect_off): Use get_dwarf2_per_objfile.
	(dwarf2_fetch_constant_bytes): Don't call dw2_setup.
	(dwarf2_fetch_die_type_sect_off): Likewise.
	(dwarf2_get_die_type): Likewise.
	(follow_die_sig_1): Use dwarf2_per_objfile from cu.
	(get_signatured_type): Likewise.
	(get_DW_AT_signature_type): Likewise.
	(dwarf_decode_macro_bytes): Add dwarf2_per_objfile parameter.
	(dwarf_decode_macros): Use dwarf2_per_objfile from cu.
	(cu_debug_loc_section): Likewise.
	(fill_in_loclist_baton): Likewise.
	(dwarf2_symbol_mark_computed): Likewise.
	(dwarf2_find_containing_comp_unit): Change objfile parameter to
	dwarf2_per_objfile.
	(free_cached_comp_units): Use dwarf2_per_objfile passed in void*
	parameter.
	(age_cached_comp_units): Add dwarf2_per_objfile parameter.
	(free_one_cached_comp_unit): Use dwarf2_per_objfile from cu.
	(dwarf2_free_objfile): Use get_dwarf2_per_objfile.
	(set_die_type): Use dwarf2_free_objfile from cu.
	(get_die_type_at_offset): Likewise.
	(dwarf2_per_objfile_free): Don't assign global variable.
	(debug_names) <constructor>: Add dwarf2_per_objfile
	parameter, update m_debugstrlookup construction.
	(debug_names::debug_str_lookup): Add dwarf2_per_objfile
	parameter.
	<m_dwarf2_per_objfile>: New field.
	<lookup>: Use m_dwarf2_per_objfile.
	(check_dwarf64_offsets): Add dwarf2_per_objfile parameter.
	(psyms_seen_size): Likewise.
	(write_gdbindex): Replace objfile parameter with
	dwarf2_per_objfile.
	(write_debug_names): Likewise.
	(write_psymtabs_to_index): Likewise.
	(save_gdb_index_command): Use get_dwarf2_per_objfile, update
	calls.