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, 15 insertions, 15 deletions

diff --git a/gdb/jit.c b/gdb/jit.c
index d9258e8..158d6d8 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -136,7 +136,7 @@ mem_bfd_iovec_stat (struct bfd *abfd, void *stream, struct stat *sb)
 
 /* Open a BFD from the target's memory.  */
 
-static struct bfd *
+static gdb_bfd_ref_ptr
 bfd_open_from_target_memory (CORE_ADDR addr, ULONGEST size, char *target)
 {
   struct target_buffer *buffer = XNEW (struct target_buffer);
@@ -892,7 +892,6 @@ jit_bfd_try_read_symtab (struct jit_code_entry *code_entry,
                          CORE_ADDR entry_addr,
                          struct gdbarch *gdbarch)
 {
-  bfd *nbfd;
   struct section_addr_info *sai;
   struct bfd_section *sec;
   struct objfile *objfile;
@@ -907,8 +906,9 @@ jit_bfd_try_read_symtab (struct jit_code_entry *code_entry,
 			paddress (gdbarch, code_entry->symfile_addr),
 			pulongest (code_entry->symfile_size));
 
-  nbfd = bfd_open_from_target_memory (code_entry->symfile_addr,
-                                      code_entry->symfile_size, gnutarget);
+  gdb_bfd_ref_ptr nbfd (bfd_open_from_target_memory (code_entry->symfile_addr,
+						     code_entry->symfile_size,
+						     gnutarget));
   if (nbfd == NULL)
     {
       puts_unfiltered (_("Error opening JITed symbol file, ignoring it.\n"));
@@ -917,42 +917,42 @@ jit_bfd_try_read_symtab (struct jit_code_entry *code_entry,
 
   /* Check the format.  NOTE: This initializes important data that GDB uses!
      We would segfault later without this line.  */
-  if (!bfd_check_format (nbfd, bfd_object))
+  if (!bfd_check_format (nbfd.get (), bfd_object))
     {
       printf_unfiltered (_("\
 JITed symbol file is not an object file, ignoring it.\n"));
-      gdb_bfd_unref (nbfd);
       return;
     }
 
   /* Check bfd arch.  */
   b = gdbarch_bfd_arch_info (gdbarch);
-  if (b->compatible (b, bfd_get_arch_info (nbfd)) != b)
+  if (b->compatible (b, bfd_get_arch_info (nbfd.get ())) != b)
     warning (_("JITed object file architecture %s is not compatible "
-               "with target architecture %s."), bfd_get_arch_info
-             (nbfd)->printable_name, b->printable_name);
+               "with target architecture %s."),
+	     bfd_get_arch_info (nbfd.get ())->printable_name,
+	     b->printable_name);
 
   /* Read the section address information out of the symbol file.  Since the
      file is generated by the JIT at runtime, it should all of the absolute
      addresses that we care about.  */
-  sai = alloc_section_addr_info (bfd_count_sections (nbfd));
+  sai = alloc_section_addr_info (bfd_count_sections (nbfd.get ()));
   old_cleanups = make_cleanup_free_section_addr_info (sai);
   i = 0;
   for (sec = nbfd->sections; sec != NULL; sec = sec->next)
-    if ((bfd_get_section_flags (nbfd, sec) & (SEC_ALLOC|SEC_LOAD)) != 0)
+    if ((bfd_get_section_flags (nbfd.get (), sec) & (SEC_ALLOC|SEC_LOAD)) != 0)
       {
         /* We assume that these virtual addresses are absolute, and do not
            treat them as offsets.  */
-        sai->other[i].addr = bfd_get_section_vma (nbfd, sec);
-        sai->other[i].name = xstrdup (bfd_get_section_name (nbfd, sec));
+        sai->other[i].addr = bfd_get_section_vma (nbfd.get (), sec);
+        sai->other[i].name = xstrdup (bfd_get_section_name (nbfd.get (), sec));
         sai->other[i].sectindex = sec->index;
         ++i;
       }
   sai->num_sections = i;
 
   /* This call does not take ownership of SAI.  */
-  make_cleanup_bfd_unref (nbfd);
-  objfile = symbol_file_add_from_bfd (nbfd, bfd_get_filename (nbfd), 0, sai,
+  objfile = symbol_file_add_from_bfd (nbfd.get (),
+				      bfd_get_filename (nbfd.get ()), 0, sai,
 				      OBJF_SHARED | OBJF_NOT_FILENAME, NULL);
 
   do_cleanups (old_cleanups);