[Windows/RFA/commit] Deprecate windows-specific dll-symbols command and aliases

Joel Brobecker
2014-01-31T09:48:34Z

Hello,

The "dll-symbols" command, specific to native Windows platforms,
gives the impression that the symbols were not loaded, first
because it completes silently, and second because the "info shared"
output does not get updated after the command completes:

(gdb) dll-symbols C:\WINDOWS\syswow64\rpcrt4.dll
(gdb) info shared
From To Syms Read Shared Object Library
[...]
0x77e51000 0x77ee2554 No C:\WINDOWS\system32\rpcrt4.dll

(we exected the "Syms Read" column to read "Yes").

As far as I can tell, the symbols actually do get loaded, but completely
independently from the solib framework, which explains the silent
loading and the fact that the "Syms Read" column does not get updated.
See windows-nat.c::safe_symbol_file_add_stub, which calls symbol_file_add
instead of calling solib_add.

But, aside from the fact that the "Syms Read" status does not get
updated, I also noticed that it does not take into account the DLL's
actual load address when loading its symbols. As a result, I believe
that we get it wrong if the DLL does not get loaded at the prefered
address.

Rather than trying to fix this command, there does not seem to be
a reason other than historical for having Windows-specific commands
which essentially re-implements the "sharedlibrary" command. The
command interface is slightly different (the latter takes a regexp
rather than a plain filename), but it should be just as easy to use
the "sharedlibrary" command, or its "share" alias, as usisng the
"dll-symbols" command. For instance:

(gdb) share rpcrt4.dll
Reading symbols from C:\WINDOWS\system32\rpcrt4.dll...(no debugging symbols found)...done.
Loaded symbols for C:\WINDOWS\system32\rpcrt4.dll
(gdb) info shared
From To Syms Read Shared Object Library
[...]
0x77e51000 0x77ee2554 Yes (*) C:\WINDOWS\system32\rpcrt4.dll

This patch therefore deprecates the "dll-symbols" command, as well
as its two aliases "add-shared-symbol-files" and "assf", with a view
of deleting them as soon as the 7.8 branch gets cut.

Another option is to port this patch to the gdb-7.7 branch to make it
deprecated in the 7.7 release, allowing us to remove support for these
commands from master now.

gdb/ChangeLog:

* windows-nat.c (_initialize_windows_nat): Deprecate the
"dll-symbols" command. Turn the "add-shared-symbol-files"
and "assf" aliases into commands, and deprecate them as well.
* NEWS: Add entry explaining that "dll-symbols" and its two
aliases are now deprecated.

Tested on x86-windows. Thoughts?

Thanks,
--
Joel

---
gdb/NEWS | 4 ++++
gdb/windows-nat.c | 13 +++++++++----
2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index 5062e02..14af602 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -51,6 +51,10 @@ qXfer:btrace:read's annex
The qXfer:btrace:read packet supports a new annex 'delta' to read
branch trace incrementally.

+* The "dll-symbols" command, and its two aliases ("add-shared-symbol-files"
+ and "assf"), have been deprecated. Use the "sharedlibrary" command, or
+ its alias "share", instead.
+
*** Changes in GDB 7.7

* Improved support for process record-replay and reverse debugging on
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 5bcb7b7..68a567b 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -2666,12 +2666,17 @@ _initialize_windows_nat (void)
c = add_com ("dll-symbols", class_files, dll_symbol_command,
_("Load dll library symbols from FILE."));
set_cmd_completer (c, filename_completer);
+ deprecate_cmd (c, "sharedlibrary");

- add_com_alias ("sharedlibrary", "dll-symbols", class_alias, 1);
-
- add_com_alias ("add-shared-symbol-files", "dll-symbols", class_alias, 1);
+ c = add_com ("add-shared-symbol-files", class_files, dll_symbol_command,
+ _("Load dll library symbols from FILE."));
+ set_cmd_completer (c, filename_completer);
+ deprecate_cmd (c, "sharedlibrary");

- add_com_alias ("assf", "dll-symbols", class_alias, 1);
+ c = add_com ("assf", class_files, dll_symbol_command,
+ _("Load dll library symbols from FILE."));
+ set_cmd_completer (c, filename_completer);
+ deprecate_cmd (c, "sharedlibrary");

#ifdef __CYGWIN__
add_setshow_boolean_cmd ("shell", class_support, &useshell, _("\
--
1.8.3.2