Change section_offsets to a std::vector

This changes section_offsets to be specialization of a std::vector and
updates all the users.  It also removes the ANOFFSET and
SIZEOF_N_SECTION_OFFSETS macros.

Most of this is just a generic sort of cleanup, that reduces the
number of lines of code.  However, a couple spots were doing weird
things.

objfile_relocate did:

-      std::vector<struct section_offsets>
-	new_debug_offsets (SIZEOF_N_SECTION_OFFSETS (debug_objfile->num_sections));

... which seems to greatly over-estimate the number of elements
needed.

This appeared in set_objfile_default_section_offset:

-  std::vector<struct section_offsets> offsets (objf->num_sections,
-					       { { offset } });

... which makes sense due to type safety, but is also actively
confusing given that section_offsets was previously also a kind of
vector type.

Tested on x86-64 Fedora 30.

gdb/ChangeLog
2020-01-08  Tom Tromey  <tromey@adacore.com>

	* xcoffread.c (enter_line_range, read_xcoff_symtab)
	(process_xcoff_symbol, xcoff_symfile_offsets): Update.
	* symtab.h (MSYMBOL_VALUE_ADDRESS): Update.
	(struct section_offsets, ANOFFSET, SIZEOF_N_SECTION_OFFSETS):
	Remove.
	(section_offsets): New typedef.
	* symtab.c (fixup_section, get_msymbol_address): Update.
	* symmisc.c (dump_msymbols): Update.
	* symfile.h (relative_addr_info_to_section_offsets)
	(symfile_map_offsets_to_segments): Update.
	* symfile.c (build_section_addr_info_from_objfile)
	(init_objfile_sect_indices): Update.
	(struct place_section_arg): Change type of "offsets".
	(place_section): Update.
	(relative_addr_info_to_section_offsets): Change type of
	"section_offsets".  Remove "num_sections" parameter.
	(default_symfile_offsets, syms_from_objfile_1)
	(set_objfile_default_section_offset): Update.
	(reread_symbols): No need to preserve section offsets by hand.
	(symfile_map_offsets_to_segments): Change type of "offsets".
	* stap-probe.c (relocate_address): Update.
	* stabsread.h (process_one_symbol): Update.
	* solib-target.c (struct lm_info_target) <offsets>: Change type.
	(solib_target_relocate_section_addresses): Update.
	* solib-svr4.c (enable_break, svr4_relocate_main_executable):
	Update.
	* solib-frv.c (frv_relocate_main_executable): Update.
	* solib-dsbt.c (dsbt_relocate_main_executable): Update.
	* solib-aix.c (solib_aix_get_section_offsets): Change return
	type.
	(solib_aix_solib_create_inferior_hook): Update.
	* remote.c (remote_target::get_offsets): Update.
	* psymtab.c (find_pc_sect_psymtab): Update.
	* psympriv.h (struct partial_symbol) <address, text_low,
	text_high>: Update.
	* objfiles.h (obj_section_offset): Update.
	(struct objfile) <section_offsets>: Change type.
	<num_sections>: Remove.
	(objfile_relocate): Update.
	* objfiles.c (entry_point_address_query): Update
	(relocate_one_symbol): Change type of "section_offsets".
	(objfile_relocate1, objfile_relocate1): Change type of
	"new_offsets".
	(objfile_rebase1): Update.
	* mipsread.c (mipscoff_symfile_read): Update.
	(read_alphacoff_dynamic_symtab): Remove "section_offsets"
	parameter.
	* mdebugread.c (parse_symbol): Change type of "section_offsets".
	(parse_external, psymtab_to_symtab_1): Update.
	* machoread.c (macho_symfile_offsets): Update.
	* ia64-tdep.c (ia64_find_unwind_table): Update.
	* hppa-tdep.c (read_unwind_info): Update.
	* hppa-bsd-tdep.c (hppabsd_find_global_pointer): Update.
	* dwarf2read.c (create_addrmap_from_index)
	(create_addrmap_from_aranges, dw2_find_pc_sect_compunit_symtab)
	(process_psymtab_comp_unit_reader, add_partial_symbol)
	(add_partial_subprogram, process_full_comp_unit)
	(read_file_scope, read_func_scope, read_lexical_block_scope)
	(read_call_site_scope, dwarf2_rnglists_process)
	(dwarf2_ranges_process, dwarf2_ranges_read)
	(dwarf_decode_lines_1, var_decode_location, new_symbol)
	(dwarf2_fetch_die_loc_sect_off, dwarf2_per_cu_text_offset):
	Update.
	* dwarf2-frame.c (execute_cfa_program, dwarf2_frame_find_fde):
	Update.
	* dtrace-probe.c (dtrace_probe::get_relocated_address): Update.
	* dbxread.c (read_dbx_symtab, read_ofile_symtab): Update.
	(process_one_symbol): Change type of "section_offsets".
	* ctfread.c (get_objfile_text_range): Update.
	* coffread.c (coff_symtab_read, enter_linenos)
	(process_coff_symbol): Update.
	* coff-pe-read.c (add_pe_forwarded_sym): Update.
	* amd64-windows-tdep.c (amd64_windows_find_unwind_info): Update.

Change-Id: I147eb967e9b44d82f4048039de7bb44b80cd72fb

gdb/machoread.c

@@ -907,12 +907,7 @@ macho_symfile_offsets (struct objfile *objfile,
   struct obj_section *osect;
 
   /* Allocate section_offsets.  */
-  objfile->num_sections = bfd_count_sections (objfile->obfd);
-  objfile->section_offsets = (struct section_offsets *)
-    obstack_alloc (&objfile->objfile_obstack,
-                   SIZEOF_N_SECTION_OFFSETS (objfile->num_sections));
-  memset (objfile->section_offsets, 0,
-          SIZEOF_N_SECTION_OFFSETS (objfile->num_sections));
+  objfile->section_offsets.assign (bfd_count_sections (objfile->obfd), 0);
 
   /* This code is run when we first add the objfile with
      symfile_add_with_addrs_or_offsets, when "addrs" not "offsets" are