[1/2] Look for separate debug files in debug directories under a sysroot.
Commit Message
When an object file is present in a system root, GDB currently looks
for separate debug files under the global debugfile directories. For
example, if the sysroot is set to "/myroot" and hte global debugfile
directory is set to "/usr/lib/debug", GDB will look for a separate
debug file for "/myroot/lib/libc.so.7" in the following paths:
/myroot/lib/libc.so.7.debug
/myroot/lib/.debug/libc.so.7.debug
/usr/lib/debug//myroot/lib/libc.so.7.debug
/usr/lib/debug/lib/libc.so.7.debug
However, some system roots include a full system installation
including a nested global debugfile directory under the sysroot. This
patch adds an additional check to support such systems. In the
example above the additional path searched is:
/myroot/usr/lib/debug/lib/libc.so.7.debug
To try to preserve existing behavior as much as possible, this new
path is searched last for each global debugfile directory.
gdb/ChangeLog:
* symfile.c (find_separate_debug_file): Look for separate debug
files in debug directories under the sysroot.
---
gdb/ChangeLog | 5 +++++
gdb/symfile.c | 19 +++++++++++++++++++
2 files changed, 24 insertions(+)
Comments
On 2019-01-22 20:03, John Baldwin wrote:
> When an object file is present in a system root, GDB currently looks
> for separate debug files under the global debugfile directories. For
> example, if the sysroot is set to "/myroot" and hte global debugfile
> directory is set to "/usr/lib/debug", GDB will look for a separate
> debug file for "/myroot/lib/libc.so.7" in the following paths:
>
> /myroot/lib/libc.so.7.debug
> /myroot/lib/.debug/libc.so.7.debug
> /usr/lib/debug//myroot/lib/libc.so.7.debug
> /usr/lib/debug/lib/libc.so.7.debug
>
> However, some system roots include a full system installation
> including a nested global debugfile directory under the sysroot. This
> patch adds an additional check to support such systems. In the
> example above the additional path searched is:
>
> /myroot/usr/lib/debug/lib/libc.so.7.debug
>
> To try to preserve existing behavior as much as possible, this new
> path is searched last for each global debugfile directory.
I played with this a bit using a Raspbian sysroot. I think the behavior
you propose makes sense, perhaps more than the current behavior (I would
be curious to see a real-word case for that one). But anyway, keeping
the old behavior and adding a new one is fine. It's rather cheap to
check many possible locations, and since there's a crc check, there's
very little chance of loading a wrong separate debug file.
As discussed on IRC, we should probably add the same behavior for
build-id-based separate debug files.
> diff --git a/gdb/symfile.c b/gdb/symfile.c
> index 7f800add8c..c6d2c7c537 100644
> --- a/gdb/symfile.c
> +++ b/gdb/symfile.c
> @@ -1465,6 +1465,25 @@ find_separate_debug_file (const char *dir,
> if (separate_debug_file_exists (debugfile, crc32, objfile))
> return debugfile;
> }
> +
> + /* If the file is in the sysroot, try using its base path in the
> + sysroot's global debugfile directory. */
> + if (canon_dir != NULL
> + && filename_ncmp (canon_dir, gdb_sysroot,
> + strlen (gdb_sysroot)) == 0
> + && IS_DIR_SEPARATOR (canon_dir[strlen (gdb_sysroot)]))
> + {
Is there any reason to duplicate the if above? It looks to be the same
as the previous check, so the new code could go in the existing if.
> + debugfile = target_prefix ? "target:" : "";
> + debugfile += gdb_sysroot;
> + debugfile += debugdir.get ();
> + debugfile += (canon_dir + strlen (gdb_sysroot));
> + debugfile += "/";
> + debugfile += debuglink;
> +
> + if (separate_debug_file_exists (debugfile, crc32, objfile))
> + return debugfile;
> + }
> +
Simon
@@ -1,3 +1,8 @@
+2019-01-22 John Baldwin <jhb@FreeBSD.org>
+
+ * symfile.c (find_separate_debug_file): Look for separate debug
+ files in debug directories under the sysroot.
+
2019-01-22 John Baldwin <jhb@FreeBSD.org>
* ppc-fbsd-tdep.c (ppcfbsd_get_thread_local_address): New.
@@ -1465,6 +1465,25 @@ find_separate_debug_file (const char *dir,
if (separate_debug_file_exists (debugfile, crc32, objfile))
return debugfile;
}
+
+ /* If the file is in the sysroot, try using its base path in the
+ sysroot's global debugfile directory. */
+ if (canon_dir != NULL
+ && filename_ncmp (canon_dir, gdb_sysroot,
+ strlen (gdb_sysroot)) == 0
+ && IS_DIR_SEPARATOR (canon_dir[strlen (gdb_sysroot)]))
+ {
+ debugfile = target_prefix ? "target:" : "";
+ debugfile += gdb_sysroot;
+ debugfile += debugdir.get ();
+ debugfile += (canon_dir + strlen (gdb_sysroot));
+ debugfile += "/";
+ debugfile += debuglink;
+
+ if (separate_debug_file_exists (debugfile, crc32, objfile))
+ return debugfile;
+ }
+
}
return std::string ();