Re: [PATCH] Mach-O: Follow Apple's dSYM files

[shinichiro hamaji <shinichiro dot hamaji at gmail dot com>]

On Tue, Dec 27, 2011 at 2:17 AM, shinichiro hamaji
<shinichiro.hamaji@gmail.com> wrote:
> Hi,
>
> Here is a patch which reads debug information from .dSYM files in the
> same directory as the executable, dylib, or bundle binary:
> http://shinh.skr.jp/t/dsym.patch
>
> To let find_line use debug BFD (in dSYM bundle) instead of the
> original executable's BFD, I used slightly different approach from
> gnu_debuglink. I factor out the part which reads debug info from
> find_line and use it from mach-o.c.
>
> If we take an approach like gnu_debuglink, we may need to add a
> function pointer to bfd_target, say _bfd_follow_debug_bfd. I think
> this is kinda overkill considering this function just returns NULL for
> all other formats.
>
> When I factor out _bfd_dwarf2_slurp_debug_info, I modified the order
> of operations in find_line. I hope this change is OK.
>
> It seems Apple's GDB checks all files under
> "foo.dSYM/Contents/Resources/DWARF" directory for an executable "foo".
> This patch checks only "foo.dSYM/Contents/Resources/DWARF/foo" and
> leave this as a TODO. This is because 1) Apple's dsymutil (a linker
> for debug information) uses this filename by default and 2) dirent.h
> is not the standard header so I need a few autoconf changes. Even if
> we need it, I'd like to do this change in different patch as this
> patch is already getting large.
>
> I ran "objdump -S" for bunch of mach-o/elf files and "make check". The
> results look OK. I'm not 100% sure if my decisions are the best. Any
> kind of suggestions will be really appreciated.
>
> bfd/
> 2011-12-27 ?Shinichiro Hamaji ?<shinichiro.hamaji@gmail.com>
>
> ? ? ? ?* dwarf2.c (_bfd_dwarf2_slurp_debug_info): Factor out the part
> ? ? ? ?which reads DWARF2 and stores in stash from find_line.
> ? ? ? ?(find_line) Call _bfd_dwarf2_slurp_debug_info.
> ? ? ? ?* libbfd-in.h (_bfd_dwarf2_slurp_debug_info): Add declaration.
> ? ? ? ?* libbfd.h (_bfd_dwarf2_slurp_debug_info): Regenerate.
> ? ? ? ?* mach-o.c (dsym_subdir): The name of subdir where debug
> ? ? ? ?information may be stored.
> ? ? ? ?(dsym_subdir_len): The length of dsym_subdir.
> ? ? ? ?(bfd_mach_o_lookup_uuid_command): New. Lookup a load command whose
> ? ? ? ?type is UUID.
> ? ? ? ?(bfd_mach_o_dsym_p): New. Check if the specified BFD is
> ? ? ? ?corresponding to the executable.
> ? ? ? ?(bfd_mach_o_find_macosx_dsym_in_fat): New. Find a debug information
> ? ? ? ?BFD in a FAT binary.
> ? ? ? ?(bfd_mach_o_find_macosx_dsym): New. Find a debug information BFD in
> ? ? ? ?the specified binary file.
> ? ? ? ?(bfd_mach_o_follow_macosx_dsym): New. Find a debug information BFD
> ? ? ? ?for the original BFD.
> ? ? ? ?(bfd_mach_o_find_nearest_line): Check dSYM files for Mach-O
> ? ? ? ?executables, dylibs, and bundles.
> ? ? ? ?(bfd_mach_o_close_and_cleanup): Clean up BFDs for the dSYM file.
> ? ? ? ?* mach-o.h (debug_filename): The filename of the dSYM file.
> ? ? ? ?(debug_bfd): The BFD of the dSYM file.
> ? ? ? ?(debug_fat_bfd): The BFD of the fat binary containing debug_bfd.
>
>
> diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
> index 767fa52..66fd16f 100644
> --- a/bfd/dwarf2.c
> +++ b/bfd/dwarf2.c
> @@ -3117,6 +3117,122 @@ stash_find_line_fast (struct dwarf2_debug *stash,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? filename_ptr, linenumber_ptr);
> ?}
>
> +/* Read debug information from DEBUG_BFD when DEBUG_BFD is specified.
> + ? If DEBUG_BFD is not specified, we read debug information from ABFD
> + ? or its gnu_debuglink. The results will be stored in PINFO.
> + ? The function returns TRUE iff debug information is ready. ?*/
> +
> +bfd_boolean
> +_bfd_dwarf2_slurp_debug_info (bfd *abfd, bfd *debug_bfd,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?const struct dwarf_debug_section *debug_sections,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?asymbol **symbols,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?void **pinfo)
> +{
> + ?bfd_size_type amt = sizeof (struct dwarf2_debug);
> + ?bfd_size_type total_size;
> + ?asection *msec;
> + ?struct dwarf2_debug *stash = (struct dwarf2_debug *) *pinfo;
> +
> + ?if (stash != NULL)
> + ? ?return TRUE;
> +
> + ?stash = (struct dwarf2_debug *) bfd_zalloc (abfd, amt);
> + ?if (! stash)
> + ? ?return FALSE;
> + ?stash->debug_sections = debug_sections;
> +
> + ?*pinfo = stash;
> +
> + ?if (debug_bfd == NULL)
> + ? ?debug_bfd = abfd;
> +
> + ?msec = find_debug_info (debug_bfd, debug_sections, NULL);
> + ?if (msec == NULL && abfd == debug_bfd)
> + ? ?{
> + ? ? ?char * debug_filename = bfd_follow_gnu_debuglink (abfd, DEBUGDIR);
> +
> + ? ? ?if (debug_filename == NULL)
> + ? ? ? /* No dwarf2 info, and no gnu_debuglink to follow.
> + ? ? ? ? ?Note that at this point the stash has been allocated, but
> + ? ? ? ? ?contains zeros. ?This lets future calls to this function
> + ? ? ? ? ?fail more quickly. ?*/
> + ? ? ? return FALSE;
> +
> + ? ? ?if ((debug_bfd = bfd_openr (debug_filename, NULL)) == NULL
> + ? ? ? ? || ! bfd_check_format (debug_bfd, bfd_object)
> + ? ? ? ? || (msec = find_debug_info (debug_bfd,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? debug_sections, NULL)) == NULL)
> + ? ? ? {
> + ? ? ? ? if (debug_bfd)
> + ? ? ? ? ? bfd_close (debug_bfd);
> + ? ? ? ? /* FIXME: Should we report our failure to follow the debuglink ? ?*/
> + ? ? ? ? free (debug_filename);
> + ? ? ? ? return FALSE;
> + ? ? ? }
> + ? ?}
> +
> + ?/* There can be more than one DWARF2 info section in a BFD these
> + ? ? days. ?First handle the easy case when there's only one. ?If
> + ? ? there's more than one, try case two: none of the sections is
> + ? ? compressed. ?In that case, read them all in and produce one
> + ? ? large stash. ?We do this in two passes - in the first pass we
> + ? ? just accumulate the section sizes, and in the second pass we
> + ? ? read in the section's contents. ?(The allows us to avoid
> + ? ? reallocing the data as we add sections to the stash.) ?If
> + ? ? some or all sections are compressed, then do things the slow
> + ? ? way, with a bunch of reallocs. ?*/
> +
> + ?if (! find_debug_info (debug_bfd, debug_sections, msec))
> + ? ?{
> + ? ? ?/* Case 1: only one info section. ?*/
> + ? ? ?total_size = msec->size;
> + ? ? ?if (! read_section (debug_bfd, &stash->debug_sections[debug_info],
> + ? ? ? ? ? ? ? ? ? ? ? ? symbols, 0,
> + ? ? ? ? ? ? ? ? ? ? ? ? &stash->info_ptr_memory, &total_size))
> + ? ? ? return FALSE;
> + ? ?}
> + ?else
> + ? ?{
> + ? ? ?/* Case 2: multiple sections. ?*/
> + ? ? ?for (total_size = 0;
> + ? ? ? ? ?msec;
> + ? ? ? ? ?msec = find_debug_info (debug_bfd, debug_sections, msec))
> + ? ? ? total_size += msec->size;
> +
> + ? ? ?stash->info_ptr_memory = (bfd_byte *) bfd_malloc (total_size);
> + ? ? ?if (stash->info_ptr_memory == NULL)
> + ? ? ? return FALSE;
> +
> + ? ? ?total_size = 0;
> + ? ? ?for (msec = find_debug_info (debug_bfd, debug_sections, NULL);
> + ? ? ? ? ?msec;
> + ? ? ? ? ?msec = find_debug_info (debug_bfd, debug_sections, msec))
> + ? ? ? {
> + ? ? ? ? bfd_size_type size;
> +
> + ? ? ? ? size = msec->size;
> + ? ? ? ? if (size == 0)
> + ? ? ? ? ? continue;
> +
> + ? ? ? ? if (!(bfd_simple_get_relocated_section_contents
> + ? ? ? ? ? ? ? (debug_bfd, msec, stash->info_ptr_memory + total_size,
> + ? ? ? ? ? ? ? ?symbols)))
> + ? ? ? ? ? return FALSE;
> +
> + ? ? ? ? total_size += size;
> + ? ? ? }
> + ? ?}
> +
> + ?stash->info_ptr = stash->info_ptr_memory;
> + ?stash->info_ptr_end = stash->info_ptr + total_size;
> + ?stash->sec = find_debug_info (debug_bfd, debug_sections, NULL);
> + ?stash->sec_info_ptr = stash->info_ptr;
> + ?stash->syms = symbols;
> + ?stash->bfd_ptr = debug_bfd;
> +
> + ?return TRUE;
> +}
> +
> ?/* Find the source code location of SYMBOL. ?If SYMBOL is NULL
> ? ?then find the nearest source code location corresponding to
> ? ?the address SECTION + OFFSET.
> @@ -3157,17 +3273,16 @@ find_line (bfd *abfd,
> ? bfd_vma found = FALSE;
> ? bfd_boolean do_line;
>
> - ?stash = (struct dwarf2_debug *) *pinfo;
> + ?*filename_ptr = NULL;
> + ?if (functionname_ptr != NULL)
> + ? ?*functionname_ptr = NULL;
> + ?*linenumber_ptr = 0;
>
> - ?if (! stash)
> - ? ?{
> - ? ? ?bfd_size_type amt = sizeof (struct dwarf2_debug);
> + ?if (! _bfd_dwarf2_slurp_debug_info (abfd, NULL,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? debug_sections, symbols, pinfo))
> + ? ?return FALSE;
>
> - ? ? ?stash = (struct dwarf2_debug *) bfd_zalloc (abfd, amt);
> - ? ? ?if (! stash)
> - ? ? ? return FALSE;
> - ? ? ?stash->debug_sections = debug_sections;
> - ? ?}
> + ?stash = (struct dwarf2_debug *) *pinfo;
>
> ? /* In a relocatable file, 2 functions may have the same address.
> ? ? ?We change the section vma so that they won't overlap. ?*/
> @@ -3197,110 +3312,11 @@ find_line (bfd *abfd,
> ? ? addr += section->output_section->vma + section->output_offset;
> ? else
> ? ? addr += section->vma;
> - ?*filename_ptr = NULL;
> - ?if (! do_line)
> - ? ?*functionname_ptr = NULL;
> - ?*linenumber_ptr = 0;
> -
> - ?if (! *pinfo)
> - ? ?{
> - ? ? ?bfd *debug_bfd;
> - ? ? ?bfd_size_type total_size;
> - ? ? ?asection *msec;
> -
> - ? ? ?*pinfo = stash;
> -
> - ? ? ?msec = find_debug_info (abfd, debug_sections, NULL);
> - ? ? ?if (msec == NULL)
> - ? ? ? {
> - ? ? ? ? char * debug_filename = bfd_follow_gnu_debuglink (abfd, DEBUGDIR);
> -
> - ? ? ? ? if (debug_filename == NULL)
> - ? ? ? ? ? /* No dwarf2 info, and no gnu_debuglink to follow.
> - ? ? ? ? ? ? ?Note that at this point the stash has been allocated, but
> - ? ? ? ? ? ? ?contains zeros. ?This lets future calls to this function
> - ? ? ? ? ? ? ?fail more quickly. ?*/
> - ? ? ? ? ? goto done;
> -
> - ? ? ? ? if ((debug_bfd = bfd_openr (debug_filename, NULL)) == NULL
> - ? ? ? ? ? ? || ! bfd_check_format (debug_bfd, bfd_object)
> - ? ? ? ? ? ? || (msec = find_debug_info (debug_bfd,
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?debug_sections, NULL)) == NULL)
> - ? ? ? ? ? {
> - ? ? ? ? ? ? if (debug_bfd)
> - ? ? ? ? ? ? ? bfd_close (debug_bfd);
> - ? ? ? ? ? ? /* FIXME: Should we report our failure to follow the debuglink ? ?*/
> - ? ? ? ? ? ? free (debug_filename);
> - ? ? ? ? ? ? goto done;
> - ? ? ? ? ? }
> - ? ? ? }
> - ? ? ?else
> - ? ? ? debug_bfd = abfd;
> -
> - ? ? ?/* There can be more than one DWARF2 info section in a BFD these
> - ? ? ? ?days. ?First handle the easy case when there's only one. ?If
> - ? ? ? ?there's more than one, try case two: none of the sections is
> - ? ? ? ?compressed. ?In that case, read them all in and produce one
> - ? ? ? ?large stash. ?We do this in two passes - in the first pass we
> - ? ? ? ?just accumulate the section sizes, and in the second pass we
> - ? ? ? ?read in the section's contents. ?(The allows us to avoid
> - ? ? ? ?reallocing the data as we add sections to the stash.) ?If
> - ? ? ? ?some or all sections are compressed, then do things the slow
> - ? ? ? ?way, with a bunch of reallocs. ?*/
> -
> - ? ? ?if (! find_debug_info (debug_bfd, debug_sections, msec))
> - ? ? ? {
> - ? ? ? ? /* Case 1: only one info section. ?*/
> - ? ? ? ? total_size = msec->size;
> - ? ? ? ? if (! read_section (debug_bfd, &stash->debug_sections[debug_info],
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?symbols, 0,
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? &stash->info_ptr_memory, &total_size))
> - ? ? ? ? ? goto done;
> - ? ? ? }
> - ? ? ?else
> - ? ? ? {
> - ? ? ? ? /* Case 2: multiple sections. ?*/
> - ? ? ? ? for (total_size = 0;
> - ? ? ? ? ? ? ? msec;
> - ? ? ? ? ? ? ? msec = find_debug_info (debug_bfd, debug_sections, msec))
> - ? ? ? ? ? total_size += msec->size;
> -
> - ? ? ? ? stash->info_ptr_memory = (bfd_byte *) bfd_malloc (total_size);
> - ? ? ? ? if (stash->info_ptr_memory == NULL)
> - ? ? ? ? ? goto done;
> -
> - ? ? ? ? total_size = 0;
> - ? ? ? ? for (msec = find_debug_info (debug_bfd, debug_sections, NULL);
> - ? ? ? ? ? ? ?msec;
> - ? ? ? ? ? ? ?msec = find_debug_info (debug_bfd, debug_sections, msec))
> - ? ? ? ? ? {
> - ? ? ? ? ? ? bfd_size_type size;
> -
> - ? ? ? ? ? ? size = msec->size;
> - ? ? ? ? ? ? if (size == 0)
> - ? ? ? ? ? ? ? continue;
> -
> - ? ? ? ? ? ? if (!(bfd_simple_get_relocated_section_contents
> - ? ? ? ? ? ? ? ? ? (debug_bfd, msec, stash->info_ptr_memory + total_size,
> - ? ? ? ? ? ? ? ? ? ?symbols)))
> - ? ? ? ? ? ? ? goto done;
> -
> - ? ? ? ? ? ? total_size += size;
> - ? ? ? ? ? }
> - ? ? ? }
> -
> - ? ? ?stash->info_ptr = stash->info_ptr_memory;
> - ? ? ?stash->info_ptr_end = stash->info_ptr + total_size;
> - ? ? ?stash->sec = find_debug_info (debug_bfd, debug_sections, NULL);
> - ? ? ?stash->sec_info_ptr = stash->info_ptr;
> - ? ? ?stash->syms = symbols;
> - ? ? ?stash->bfd_ptr = debug_bfd;
> - ? ?}
>
> ? /* A null info_ptr indicates that there is no dwarf2 info
> ? ? ?(or that an error occured while setting up the stash). ?*/
> ? if (! stash->info_ptr)
> - ? ?goto done;
> + ? ?return FALSE;
>
> ? stash->inliner_chain = NULL;
>
> diff --git a/bfd/libbfd-in.h b/bfd/libbfd-in.h
> index 7db09e4..f7a9e21 100644
> --- a/bfd/libbfd-in.h
> +++ b/bfd/libbfd-in.h
> @@ -549,6 +549,10 @@ bfd_boolean _bfd_generic_find_line
> ?extern bfd_boolean _bfd_dwarf2_find_inliner_info
> ? (bfd *, const char **, const char **, unsigned int *, void **);
>
> +/* Read DWARF 2 debugging information. */
> +extern bfd_boolean _bfd_dwarf2_slurp_debug_info
> + ?(bfd *, bfd *, const struct dwarf_debug_section *, asymbol **, void **);
> +
> ?/* Clean up the data used to handle DWARF 2 debugging information. */
> ?extern void _bfd_dwarf2_cleanup_debug_info
> ? (bfd *, void **);
> diff --git a/bfd/libbfd.h b/bfd/libbfd.h
> index 0beddb6..a10a651 100644
> --- a/bfd/libbfd.h
> +++ b/bfd/libbfd.h
> @@ -554,6 +554,10 @@ bfd_boolean _bfd_generic_find_line
> ?extern bfd_boolean _bfd_dwarf2_find_inliner_info
> ? (bfd *, const char **, const char **, unsigned int *, void **);
>
> +/* Read DWARF 2 debugging information. */
> +extern bfd_boolean _bfd_dwarf2_slurp_debug_info
> + ?(bfd *, bfd *, const struct dwarf_debug_section *, asymbol **, void **);
> +
> ?/* Clean up the data used to handle DWARF 2 debugging information. */
> ?extern void _bfd_dwarf2_cleanup_debug_info
> ? (bfd *, void **);
> diff --git a/bfd/mach-o.c b/bfd/mach-o.c
> index cc68d89..f46f94d 100644
> --- a/bfd/mach-o.c
> +++ b/bfd/mach-o.c
> @@ -277,6 +277,9 @@ static const mach_o_segment_name_xlat segsec_names_xlat[] =
> ? ? { NULL, NULL }
> ? };
>
> +static const char dsym_subdir[] = ".dSYM/Contents/Resources/DWARF";
> +static const int dsym_subdir_len = sizeof(dsym_subdir);
> +
> ?/* For both cases bfd-name => mach-o name and vice versa, the specific target
> ? ?is checked before the generic. ?This allows a target (e.g. ppc for cstring)
> ? ?to override the generic definition with a more specific one. ?*/
> @@ -3738,6 +3741,152 @@ bfd_mach_o_core_file_failing_signal (bfd *abfd
> ATTRIBUTE_UNUSED)
> ? return 0;
> ?}
>
> +static bfd_mach_o_uuid_command *
> +bfd_mach_o_lookup_uuid_command (bfd *abfd)
> +{
> + ?bfd_mach_o_load_command *uuid_cmd;
> + ?int ncmd = bfd_mach_o_lookup_command (abfd, BFD_MACH_O_LC_UUID, &uuid_cmd);
> + ?if (ncmd != 1)
> + ? ?return FALSE;
> + ?return &uuid_cmd->command.uuid;
> +}
> +
> +static bfd_boolean
> +bfd_mach_o_dsym_p (bfd *debug_bfd, bfd_mach_o_uuid_command *uuid_cmd)
> +{
> + ?bfd_mach_o_uuid_command *debug_uuid_cmd;
> +
> + ?BFD_ASSERT (debug_bfd);
> + ?BFD_ASSERT (uuid_cmd);
> +
> + ?if (!bfd_check_format (debug_bfd, bfd_object))
> + ? ?return FALSE;
> +
> + ?if (bfd_get_flavour (debug_bfd) != bfd_target_mach_o_flavour)
> + ? ?return FALSE;
> +
> + ?debug_uuid_cmd = bfd_mach_o_lookup_uuid_command (debug_bfd);
> + ?if (debug_uuid_cmd == NULL)
> + ? ?return FALSE;
> +
> + ?if (memcmp (uuid_cmd->uuid, debug_uuid_cmd->uuid,
> + ? ? ? ? ? ? ?sizeof (uuid_cmd->uuid)) != 0)
> + ? ?return FALSE;
> +
> + ?return TRUE;
> +}
> +
> +static bfd *
> +bfd_mach_o_find_macosx_dsym_in_fat (bfd *fat_bfd,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?bfd_mach_o_uuid_command *uuid_cmd)
> +{
> + ?bfd *debug_bfd = NULL, *last_bfd = NULL;
> +
> + ?BFD_ASSERT (fat_bfd);
> + ?BFD_ASSERT (uuid_cmd);
> +
> + ?for (;;)
> + ? ?{
> + ? ? ?debug_bfd = bfd_mach_o_openr_next_archived_file (fat_bfd, debug_bfd);
> + ? ? ?if (debug_bfd == NULL)
> + ? ? ? ?break;
> +
> + ? ? ?if (bfd_mach_o_dsym_p (debug_bfd, uuid_cmd))
> + ? ? ? ?break;
> +
> + ? ? ?if (last_bfd != NULL)
> + ? ? ? ?bfd_close (last_bfd);
> + ? ? ?last_bfd = debug_bfd;
> + ? ?}
> +
> + ?if (last_bfd != NULL)
> + ? ?bfd_close (last_bfd);
> + ?return debug_bfd;
> +}
> +
> +static bfd *
> +bfd_mach_o_find_macosx_dsym (bfd *abfd,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? bfd_mach_o_uuid_command *uuid_cmd,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? char *debug_filename)
> +{
> + ?bfd *debug_bfd;
> + ?bfd_mach_o_data_struct *mdata;
> +
> + ?BFD_ASSERT (abfd);
> + ?BFD_ASSERT (uuid_cmd);
> +
> + ?debug_bfd = bfd_openr (debug_filename, NULL);
> + ?if (debug_bfd == NULL)
> + ? ?return NULL;
> +
> + ?mdata = bfd_mach_o_get_data (abfd);
> +
> + ?if (bfd_check_format (debug_bfd, bfd_archive))
> + ? ?{
> + ? ? ?bfd *r = bfd_mach_o_find_macosx_dsym_in_fat (debug_bfd, uuid_cmd);
> + ? ? ?if (r)
> + ? ? ? ?{
> + ? ? ? ? ?mdata->debug_filename = debug_filename;
> + ? ? ? ? ?mdata->debug_bfd = r;
> + ? ? ? ? ?mdata->debug_fat_bfd = debug_bfd;
> + ? ? ? ?}
> + ? ? ?return r;
> + ? ?}
> +
> + ?if (bfd_mach_o_dsym_p (debug_bfd, uuid_cmd))
> + ? ?{
> + ? ? ?mdata->debug_filename = debug_filename;
> + ? ? ?mdata->debug_bfd = debug_bfd;
> + ? ? ?return debug_bfd;
> + ? ?}
> +
> + ?bfd_close (debug_bfd);
> +
> + ?return NULL;
> +}
> +
> +static bfd *
> +bfd_mach_o_follow_macosx_dsym (bfd *abfd)
> +{
> + ?char *debug_filename;
> + ?bfd_mach_o_uuid_command *uuid_cmd;
> + ?bfd *debug_bfd, *base_bfd = abfd;
> + ?const char *base_basename;
> +
> + ?if (abfd == NULL || bfd_get_flavour (abfd) != bfd_target_mach_o_flavour)
> + ? ?return NULL;
> +
> + ?if (abfd->my_archive)
> + ? ?base_bfd = abfd->my_archive;
> + ?/* BFD may have been opened from a stream. */
> + ?if (base_bfd->filename == NULL)
> + ? ?{
> + ? ? ?bfd_set_error (bfd_error_invalid_operation);
> + ? ? ?return NULL;
> + ? ?}
> + ?base_basename = lbasename (base_bfd->filename);
> +
> + ?uuid_cmd = bfd_mach_o_lookup_uuid_command (abfd);
> + ?if (uuid_cmd == NULL)
> + ? ?return NULL;
> +
> + ?/* TODO: We assume the DWARF file has the same as the binary's.
> + ? ? It seems apple's GDB checks all files in the dSYM bundle directory.
> + ? ? http://opensource.apple.com/source/gdb/gdb-1708/src/gdb/macosx/macosx-tdep.c
> + ?*/
> + ?debug_filename = (char *)bfd_malloc (strlen (base_bfd->filename)
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? + dsym_subdir_len + 1
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? + strlen (base_basename) + 1);
> + ?sprintf (debug_filename, "%s%s/%s",
> + ? ? ? ? ? base_bfd->filename, dsym_subdir, base_basename);
> +
> + ?debug_bfd = bfd_mach_o_find_macosx_dsym (abfd, uuid_cmd, debug_filename);
> + ?if (debug_bfd == NULL)
> + ? ?free (debug_filename);
> +
> + ?return debug_bfd;
> +}
> +
> ?bfd_boolean
> ?bfd_mach_o_find_nearest_line (bfd *abfd,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?asection *section,
> @@ -3748,9 +3897,30 @@ bfd_mach_o_find_nearest_line (bfd *abfd,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?unsigned int *line_ptr)
> ?{
> ? bfd_mach_o_data_struct *mdata = bfd_mach_o_get_data (abfd);
> - ?/* TODO: Handle executables and dylibs by using dSYMs. */
> - ?if (mdata->header.filetype != BFD_MACH_O_MH_OBJECT)
> + ?if (mdata == NULL)
> ? ? return FALSE;
> + ?switch (mdata->header.filetype)
> + ? ?{
> + ? ?case BFD_MACH_O_MH_OBJECT:
> + ? ? ?break;
> + ? ?case BFD_MACH_O_MH_EXECUTE:
> + ? ?case BFD_MACH_O_MH_DYLIB:
> + ? ?case BFD_MACH_O_MH_BUNDLE:
> + ? ?case BFD_MACH_O_MH_KEXT_BUNDLE:
> + ? ? ?if (mdata->dwarf2_find_line_info == NULL)
> + ? ? ? ?{
> + ? ? ? ? ?bfd *debug_bfd = bfd_mach_o_follow_macosx_dsym (abfd);
> + ? ? ? ? ?if (! debug_bfd)
> + ? ? ? ? ? ?return FALSE;

I noticed this slows down this function for files without dSYM files.
If we return here, mdata->dwarf2_find_line_info won't be filled and we
try finding separated dSYM file again and again. To fix this issue, I
changed this line to break.

The updated patch: http://shinh.skr.jp/t/dsym2.patch