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, 31 deletions

diff --git a/gdb/cli/cli-dump.c b/gdb/cli/cli-dump.c
index 9097867..9630261 100644
--- a/gdb/cli/cli-dump.c
+++ b/gdb/cli/cli-dump.c
@@ -103,45 +103,40 @@ fopen_with_cleanup (const char *filename, const char *mode)
   return file;
 }
 
-static bfd *
-bfd_openr_with_cleanup (const char *filename, const char *target)
+static gdb_bfd_ref_ptr
+bfd_openr_or_error (const char *filename, const char *target)
 {
-  bfd *ibfd;
-
-  ibfd = gdb_bfd_openr (filename, target);
+  gdb_bfd_ref_ptr ibfd (gdb_bfd_openr (filename, target));
   if (ibfd == NULL)
-    error (_("Failed to open %s: %s."), filename, 
+    error (_("Failed to open %s: %s."), filename,
 	   bfd_errmsg (bfd_get_error ()));
 
-  make_cleanup_bfd_unref (ibfd);
-  if (!bfd_check_format (ibfd, bfd_object))
+  if (!bfd_check_format (ibfd.get (), bfd_object))
     error (_("'%s' is not a recognized file format."), filename);
 
   return ibfd;
 }
 
-static bfd *
-bfd_openw_with_cleanup (const char *filename, const char *target,
-			const char *mode)
+static gdb_bfd_ref_ptr
+bfd_openw_or_error (const char *filename, const char *target, const char *mode)
 {
-  bfd *obfd;
+  gdb_bfd_ref_ptr obfd;
 
   if (*mode == 'w')	/* Write: create new file */
     {
       obfd = gdb_bfd_openw (filename, target);
       if (obfd == NULL)
-	error (_("Failed to open %s: %s."), filename, 
+	error (_("Failed to open %s: %s."), filename,
 	       bfd_errmsg (bfd_get_error ()));
-      make_cleanup_bfd_unref (obfd);
-      if (!bfd_set_format (obfd, bfd_object))
-	error (_("bfd_openw_with_cleanup: %s."), bfd_errmsg (bfd_get_error ()));
+      if (!bfd_set_format (obfd.get (), bfd_object))
+	error (_("bfd_openw_or_error: %s."), bfd_errmsg (bfd_get_error ()));
     }
   else if (*mode == 'a')	/* Append to existing file.  */
     {	/* FIXME -- doesn't work...  */
       error (_("bfd_openw does not work with append."));
     }
   else
-    error (_("bfd_openw_with_cleanup: unknown mode %s."), mode);
+    error (_("bfd_openw_or_error: unknown mode %s."), mode);
 
   return obfd;
 }
@@ -187,20 +182,19 @@ dump_bfd_file (const char *filename, const char *mode,
 	       const char *target, CORE_ADDR vaddr, 
 	       const bfd_byte *buf, ULONGEST len)
 {
-  bfd *obfd;
   asection *osection;
 
-  obfd = bfd_openw_with_cleanup (filename, target, mode);
-  osection = bfd_make_section_anyway (obfd, ".newsec");
-  bfd_set_section_size (obfd, osection, len);
-  bfd_set_section_vma (obfd, osection, vaddr);
-  bfd_set_section_alignment (obfd, osection, 0);
-  bfd_set_section_flags (obfd, osection, (SEC_HAS_CONTENTS
-					  | SEC_ALLOC
-					  | SEC_LOAD));
+  gdb_bfd_ref_ptr obfd (bfd_openw_or_error (filename, target, mode));
+  osection = bfd_make_section_anyway (obfd.get (), ".newsec");
+  bfd_set_section_size (obfd.get (), osection, len);
+  bfd_set_section_vma (obfd.get (), osection, vaddr);
+  bfd_set_section_alignment (obfd.get (), osection, 0);
+  bfd_set_section_flags (obfd.get (), osection, (SEC_HAS_CONTENTS
+						 | SEC_ALLOC
+						 | SEC_LOAD));
   osection->entsize = 0;
-  if (!bfd_set_section_contents (obfd, osection, buf, 0, len))
-    warning (_("writing dump file '%s' (%s)"), filename, 
+  if (!bfd_set_section_contents (obfd.get (), osection, buf, 0, len))
+    warning (_("writing dump file '%s' (%s)"), filename,
 	     bfd_errmsg (bfd_get_error ()));
 }
 
@@ -624,12 +618,11 @@ restore_command (char *args_in, int from_tty)
   else
     {
       /* Open the file for loading.  */
-      ibfd = bfd_openr_with_cleanup (filename, NULL);
+      gdb_bfd_ref_ptr ibfd (bfd_openr_or_error (filename, NULL));
 
       /* Process the sections.  */
-      bfd_map_over_sections (ibfd, restore_section_callback, &data);
+      bfd_map_over_sections (ibfd.get (), restore_section_callback, &data);
     }
-  return;
 }
 
 static void