Use class to manage BFD reference counts

This introduces a new specialization of gdb::ref_ptr that can be used
to manage BFD reference counts.  Then it changes most places in gdb to
use this new class, rather than explicit reference-counting or
cleanups.  This patch removes make_cleanup_bfd_unref.

If you look you will see a couple of spots using "release" where a use
of gdb_bfd_ref_ptr would be cleaner.  These will be fixed in the next
patch.

I think this patch fixes some latent bugs.  For example, it seems to
me that previously objfpy_add_separate_debug_file leaked a BFD.

I'm not 100% certain that the macho_symfile_read_all_oso change is
correct.  The existing code here is hard for me to follow.  One goal
of this sort of automated reference counting, though, is to make it
more difficult to make logic errors; so hopefully the code is clear
now.

2017-01-10  Tom Tromey  <tom@tromey.com>

	* windows-tdep.c (windows_xfer_shared_library): Update.
	* windows-nat.c (windows_make_so): Update.
	* utils.h (make_cleanup_bfd_unref): Remove.
	* utils.c (do_bfd_close_cleanup, make_cleanup_bfd_unref): Remove.
	* symfile.h (symfile_bfd_open)
	(find_separate_debug_file_in_section): Return gdb_bfd_ref_ptr.
	* symfile.c (read_symbols, symbol_file_add)
	(separate_debug_file_exists): Update.
	(symfile_bfd_open): Return gdb_bfd_ref_ptr.
	(generic_load, reread_symbols): Update.
	* symfile-mem.c (symbol_file_add_from_memory): Update.
	* spu-linux-nat.c (spu_bfd_open): Return gdb_bfd_ref_ptr.
	(spu_symbol_file_add_from_memory): Update.
	* solist.h (struct target_so_ops) <bfd_open>: Return
	gdb_bfd_ref_ptr.
	(solib_bfd_fopen, solib_bfd_open): Return gdb_bfd_ref_ptr.
	* solib.c (solib_bfd_fopen, solib_bfd_open): Return
	gdb_bfd_ref_ptr.
	(solib_map_sections, reload_shared_libraries_1): Update.
	* solib-svr4.c (enable_break): Update.
	* solib-spu.c (spu_bfd_fopen): Return gdb_bfd_ref_ptr.
	* solib-frv.c (enable_break2): Update.
	* solib-dsbt.c (enable_break): Update.
	* solib-darwin.c (gdb_bfd_mach_o_fat_extract): Return
	gdb_bfd_ref_ptr.
	(darwin_solib_get_all_image_info_addr_at_init): Update.
	(darwin_bfd_open): Return gdb_bfd_ref_ptr.
	* solib-aix.c (solib_aix_bfd_open): Return gdb_bfd_ref_ptr.
	* record-full.c (record_full_save): Update.
	* python/py-objfile.c (objfpy_add_separate_debug_file): Update.
	* procfs.c (insert_dbx_link_bpt_in_file): Update.
	* minidebug.c (find_separate_debug_file_in_section): Return
	gdb_bfd_ref_ptr.
	* machoread.c (macho_add_oso_symfile): Change abfd to
	gdb_bfd_ref_ptr.
	(macho_symfile_read_all_oso): Update.
	(macho_check_dsym): Return gdb_bfd_ref_ptr.
	(macho_symfile_read): Update.
	* jit.c (bfd_open_from_target_memory): Return gdb_bfd_ref_ptr.
	(jit_bfd_try_read_symtab): Update.
	* gdb_bfd.h (gdb_bfd_open, gdb_bfd_fopen, gdb_bfd_openr)
	(gdb_bfd_openw, gdb_bfd_openr_iovec)
	(gdb_bfd_openr_next_archived_file, gdb_bfd_fdopenr): Return
	gdb_bfd_ref_ptr.
	(gdb_bfd_ref_policy): New struct.
	(gdb_bfd_ref_ptr): New typedef.
	* gdb_bfd.c (gdb_bfd_open, gdb_bfd_fopen, gdb_bfd_openr)
	(gdb_bfd_openw, gdb_bfd_openr_iovec)
	(gdb_bfd_openr_next_archived_file, gdb_bfd_fdopenr): Return
	gdb_bfd_ref_ptr.
	* gcore.h (create_gcore_bfd): Return gdb_bfd_ref_ptr.
	* gcore.c (create_gcore_bfd): Return gdb_bfd_ref_ptr.
	(gcore_command): Update.
	* exec.c (exec_file_attach): Update.
	* elfread.c (elf_symfile_read): Update.
	* dwarf2read.c (dwarf2_get_dwz_file): Update.
	(try_open_dwop_file, open_dwo_file): Return gdb_bfd_ref_ptr.
	(open_and_init_dwo_file): Update.
	(open_dwp_file): Return gdb_bfd_ref_ptr.
	(open_and_init_dwp_file): Update.
	* corelow.c (core_open): Update.
	* compile/compile-object-load.c (compile_object_load): Update.
	* common/gdb_ref_ptr.h (ref_ptr::operator->): New operator.
	* coffread.c (coff_symfile_read): Update.
	* cli/cli-dump.c (bfd_openr_or_error, bfd_openw_or_error): Return
	gdb_bfd_ref_ptr.  Rename.
	(dump_bfd_file, restore_command): Update.
	* build-id.h (build_id_to_debug_bfd): Return gdb_bfd_ref_ptr.
	* build-id.c (build_id_to_debug_bfd): Return gdb_bfd_ref_ptr.
	(find_separate_debug_file_by_buildid): Update.

1 files changed, 9 insertions, 11 deletions

diff --git a/gdb/compile/compile-object-load.c b/gdb/compile/compile-object-load.c
index a08d68e..473e664 100644
--- a/gdb/compile/compile-object-load.c
+++ b/gdb/compile/compile-object-load.c
@@ -612,7 +612,6 @@ compile_object_load (const compile_file_names &file_names,
 		     enum compile_i_scope_types scope, void *scope_data)
 {
   struct cleanup *cleanups, *cleanups_free_objfile;
-  bfd *abfd;
   struct setup_sections_data setup_sections_data;
   CORE_ADDR addr, regs_addr, out_value_addr = 0;
   struct symbol *func_sym;
@@ -634,17 +633,16 @@ compile_object_load (const compile_file_names &file_names,
   filename = tilde_expand (file_names.object_file ());
   cleanups = make_cleanup (xfree, filename);
 
-  abfd = gdb_bfd_open (filename, gnutarget, -1);
+  gdb_bfd_ref_ptr abfd (gdb_bfd_open (filename, gnutarget, -1));
   if (abfd == NULL)
     error (_("\"%s\": could not open as compiled module: %s"),
           filename, bfd_errmsg (bfd_get_error ()));
-  make_cleanup_bfd_unref (abfd);
 
-  if (!bfd_check_format_matches (abfd, bfd_object, &matching))
+  if (!bfd_check_format_matches (abfd.get (), bfd_object, &matching))
     error (_("\"%s\": not in loadable format: %s"),
           filename, gdb_bfd_errmsg (bfd_get_error (), matching));
 
-  if ((bfd_get_file_flags (abfd) & (EXEC_P | DYNAMIC)) != 0)
+  if ((bfd_get_file_flags (abfd.get ()) & (EXEC_P | DYNAMIC)) != 0)
     error (_("\"%s\": not in object format."), filename);
 
   setup_sections_data.last_size = 0;
@@ -653,17 +651,17 @@ compile_object_load (const compile_file_names &file_names,
   setup_sections_data.last_max_alignment = 1;
   setup_sections_data.munmap_list_headp = &munmap_list_head;
   make_cleanup (munmap_listp_free_cleanup, &munmap_list_head);
-  bfd_map_over_sections (abfd, setup_sections, &setup_sections_data);
-  setup_sections (abfd, NULL, &setup_sections_data);
+  bfd_map_over_sections (abfd.get (), setup_sections, &setup_sections_data);
+  setup_sections (abfd.get (), NULL, &setup_sections_data);
 
-  storage_needed = bfd_get_symtab_upper_bound (abfd);
+  storage_needed = bfd_get_symtab_upper_bound (abfd.get ());
   if (storage_needed < 0)
     error (_("Cannot read symbols of compiled module \"%s\": %s"),
           filename, bfd_errmsg (bfd_get_error ()));
 
   /* SYMFILE_VERBOSE is not passed even if FROM_TTY, user is not interested in
      "Reading symbols from ..." message for automatically generated file.  */
-  objfile = symbol_file_add_from_bfd (abfd, filename, 0, NULL, 0, NULL);
+  objfile = symbol_file_add_from_bfd (abfd.get (), filename, 0, NULL, 0, NULL);
   cleanups_free_objfile = make_cleanup_free_objfile (objfile);
 
   func_sym = lookup_global_symbol_from_objfile (objfile,
@@ -712,7 +710,7 @@ compile_object_load (const compile_file_names &file_names,
      called from default_symfile_relocate.  */
   symbol_table = (asymbol **) obstack_alloc (&objfile->objfile_obstack,
 					     storage_needed);
-  number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
+  number_of_symbols = bfd_canonicalize_symtab (abfd.get (), symbol_table);
   if (number_of_symbols < 0)
     error (_("Cannot parse symbols of compiled module \"%s\": %s"),
           filename, bfd_errmsg (bfd_get_error ()));
@@ -771,7 +769,7 @@ compile_object_load (const compile_file_names &file_names,
   if (missing_symbols)
     error (_("%ld symbols were missing, cannot continue."), missing_symbols);
 
-  bfd_map_over_sections (abfd, copy_sections, symbol_table);
+  bfd_map_over_sections (abfd.get (), copy_sections, symbol_table);
 
   regs_type = get_regs_type (func_sym, objfile);
   if (regs_type == NULL)