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, 11 insertions, 12 deletions

diff --git a/gdb/solib-dsbt.c b/gdb/solib-dsbt.c
index cbc58d3..c407106 100644
--- a/gdb/solib-dsbt.c
+++ b/gdb/solib-dsbt.c
@@ -816,7 +816,6 @@ enable_break (void)
     {
       unsigned int interp_sect_size;
       char *buf;
-      bfd *tmp_bfd = NULL;
       CORE_ADDR addr;
       struct int_elf32_dsbt_loadmap *ldm;
       int ret;
@@ -832,6 +831,7 @@ enable_break (void)
 	 loaded so that we can load its symbols and place a breakpoint
 	 in the dynamic linker itself.  */
 
+      gdb_bfd_ref_ptr tmp_bfd;
       TRY
 	{
 	  tmp_bfd = solib_bfd_open (buf);
@@ -852,29 +852,31 @@ enable_break (void)
 
       /* Record the relocated start and end address of the dynamic linker
 	 text and plt section for dsbt_in_dynsym_resolve_code.  */
-      interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
+      interp_sect = bfd_get_section_by_name (tmp_bfd.get (), ".text");
       if (interp_sect)
 	{
 	  info->interp_text_sect_low
-	    = bfd_section_vma (tmp_bfd, interp_sect);
+	    = bfd_section_vma (tmp_bfd.get (), interp_sect);
 	  info->interp_text_sect_low
 	    += displacement_from_map (ldm, info->interp_text_sect_low);
 	  info->interp_text_sect_high
 	    = info->interp_text_sect_low
-	    + bfd_section_size (tmp_bfd, interp_sect);
+	    + bfd_section_size (tmp_bfd.get (), interp_sect);
 	}
-      interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
+      interp_sect = bfd_get_section_by_name (tmp_bfd.get (), ".plt");
       if (interp_sect)
 	{
 	  info->interp_plt_sect_low =
-	    bfd_section_vma (tmp_bfd, interp_sect);
+	    bfd_section_vma (tmp_bfd.get (), interp_sect);
 	  info->interp_plt_sect_low
 	    += displacement_from_map (ldm, info->interp_plt_sect_low);
 	  info->interp_plt_sect_high =
-	    info->interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+	    info->interp_plt_sect_low + bfd_section_size (tmp_bfd.get (),
+							  interp_sect);
 	}
 
-      addr = gdb_bfd_lookup_symbol (tmp_bfd, cmp_name, "_dl_debug_state");
+      addr = gdb_bfd_lookup_symbol (tmp_bfd.get (), cmp_name,
+				    "_dl_debug_state");
       if (addr != 0)
 	{
 	  if (solib_dsbt_debug)
@@ -901,10 +903,7 @@ enable_break (void)
 	  ret = 0;
 	}
 
-      /* We're done with the temporary bfd.  */
-      gdb_bfd_unref (tmp_bfd);
-
-      /* We're also done with the loadmap.  */
+      /* We're done with the loadmap.  */
       xfree (ldm);
 
       return ret;