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, 24 insertions, 41 deletions

diff --git a/gdb/solib-aix.c b/gdb/solib-aix.c
index 332d1e4..66add03 100644
--- a/gdb/solib-aix.c
+++ b/gdb/solib-aix.c
@@ -624,7 +624,7 @@ solib_aix_in_dynsym_resolve_code (CORE_ADDR pc)
 
 /* Implement the "bfd_open" target_so_ops method.  */
 
-static bfd *
+static gdb_bfd_ref_ptr
 solib_aix_bfd_open (char *pathname)
 {
   /* The pathname is actually a synthetic filename with the following
@@ -635,11 +635,7 @@ solib_aix_bfd_open (char *pathname)
      to the solib's lm_info here?  */
   const int path_len = strlen (pathname);
   char *sep;
-  char *filename;
   int filename_len;
-  char *member_name;
-  bfd *archive_bfd, *object_bfd;
-  struct cleanup *cleanup;
   int found_file;
   char *found_pathname;
 
@@ -658,69 +654,57 @@ solib_aix_bfd_open (char *pathname)
     }
   filename_len = sep - pathname;
 
-  filename = xstrprintf ("%.*s", filename_len, pathname);
-  cleanup = make_cleanup (xfree, filename);
-  member_name = xstrprintf ("%.*s", path_len - filename_len - 2, sep + 1);
-  make_cleanup (xfree, member_name);
+  std::string filename (string_printf ("%.*s", filename_len, pathname));
+  std::string member_name (string_printf ("%.*s", path_len - filename_len - 2,
+					  sep + 1));
 
   /* Calling solib_find makes certain that sysroot path is set properly
      if program has a dependency on .a archive and sysroot is set via
      set sysroot command.  */
-  found_pathname = solib_find (filename, &found_file);
+  found_pathname = solib_find (filename.c_str (), &found_file);
   if (found_pathname == NULL)
       perror_with_name (pathname);
-  archive_bfd = solib_bfd_fopen (found_pathname, found_file);
+  gdb_bfd_ref_ptr archive_bfd (solib_bfd_fopen (found_pathname, found_file));
   if (archive_bfd == NULL)
     {
       warning (_("Could not open `%s' as an executable file: %s"),
-	       filename, bfd_errmsg (bfd_get_error ()));
-      do_cleanups (cleanup);
+	       filename.c_str (), bfd_errmsg (bfd_get_error ()));
       return NULL;
     }
 
-  if (bfd_check_format (archive_bfd, bfd_object))
-    {
-      do_cleanups (cleanup);
-      return archive_bfd;
-    }
+  if (bfd_check_format (archive_bfd.get (), bfd_object))
+    return archive_bfd;
 
-  if (! bfd_check_format (archive_bfd, bfd_archive))
+  if (! bfd_check_format (archive_bfd.get (), bfd_archive))
     {
       warning (_("\"%s\": not in executable format: %s."),
-	       filename, bfd_errmsg (bfd_get_error ()));
-      gdb_bfd_unref (archive_bfd);
-      do_cleanups (cleanup);
+	       filename.c_str (), bfd_errmsg (bfd_get_error ()));
       return NULL;
     }
 
-  object_bfd = gdb_bfd_openr_next_archived_file (archive_bfd, NULL);
+  gdb_bfd_ref_ptr object_bfd
+    (gdb_bfd_openr_next_archived_file (archive_bfd.get (), NULL));
   while (object_bfd != NULL)
     {
-      bfd *next;
-
-      if (strcmp (member_name, object_bfd->filename) == 0)
+      if (member_name == object_bfd->filename)
 	break;
 
-      next = gdb_bfd_openr_next_archived_file (archive_bfd, object_bfd);
-      gdb_bfd_unref (object_bfd);
-      object_bfd = next;
+      object_bfd = gdb_bfd_openr_next_archived_file (archive_bfd.get (),
+						     object_bfd.get ());
     }
 
   if (object_bfd == NULL)
     {
-      warning (_("\"%s\": member \"%s\" missing."), filename, member_name);
-      gdb_bfd_unref (archive_bfd);
-      do_cleanups (cleanup);
+      warning (_("\"%s\": member \"%s\" missing."), filename.c_str (),
+	       member_name.c_str ());
       return NULL;
     }
 
-  if (! bfd_check_format (object_bfd, bfd_object))
+  if (! bfd_check_format (object_bfd.get (), bfd_object))
     {
       warning (_("%s(%s): not in object format: %s."),
-	       filename, member_name, bfd_errmsg (bfd_get_error ()));
-      gdb_bfd_unref (archive_bfd);
-      gdb_bfd_unref (object_bfd);
-      do_cleanups (cleanup);
+	       filename.c_str (), member_name.c_str (),
+	       bfd_errmsg (bfd_get_error ()));
       return NULL;
     }
 
@@ -728,12 +712,11 @@ solib_aix_bfd_open (char *pathname)
      along with appended parenthesized member name in order to allow commands
      listing all shared libraries to display.  Otherwise, we would only be
      displaying the name of the archive member object.  */
-  xfree (bfd_get_filename (object_bfd));
+  xfree (bfd_get_filename (object_bfd.get ()));
   object_bfd->filename = xstrprintf ("%s%s",
-                                     bfd_get_filename (archive_bfd), sep);
+                                     bfd_get_filename (archive_bfd.get ()),
+				     sep);
 
-  gdb_bfd_unref (archive_bfd);
-  do_cleanups (cleanup);
   return object_bfd;
 }