Re: [RFC - Python] New ObjFile event

Kevin Pouget
2011-03-30T09:25:20Z

Hello,

here is a patch with all the modifications we discussed so far,
including the ChangeLog entry and the new files

Cordially,

Kevin

--
From eec9cb69818ec72184b59ca0d928fcbc590c558f Mon Sep 17 00:00:00 2001
From: Kevin Pouget <kevin.pouget@st.com>
Date: Tue, 29 Mar 2011 11:26:34 -0400
Subject: [PATCH] Allow Python notification of new object-file loadings

Signed-off-by: Kevin Pouget <kevin.pouget@st.com>
---
gdb/ChangeLog                              |   28 +++++++++++++++
gdb/Makefile.in                            |   11 +++++-
gdb/doc/gdb.texinfo                        |   14 +++++--
gdb/python/py-event.h                      |    1 +
gdb/python/py-events.h                     |    1 +
gdb/python/py-evts.c                       |    3 ++
gdb/python/py-inferior.c                   |   27 ++++++++++++++
gdb/python/py-newobjfileevent.c            |   53 ++++++++++++++++++++++++++++
gdb/python/python-internal.h               |    2 +
gdb/python/python.c                        |    6 ++-
gdb/testsuite/gdb.python/py-events-shlib.c |   20 ++++++++++
gdb/testsuite/gdb.python/py-events.c       |    3 ++
gdb/testsuite/gdb.python/py-events.exp     |   32 ++++++++++++++---
gdb/testsuite/gdb.python/py-events.py      |   20 ++++++++++
14 files changed, 208 insertions(+), 13 deletions(-)
create mode 100644 gdb/python/py-newobjfileevent.c
create mode 100644 gdb/testsuite/gdb.python/py-events-shlib.c

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 03885dd..2bceb45 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,31 @@
+2011-03-29 Kevin Pouget <kevin.pouget@st.com>
+
+    Allow Python notification of new object-file loadings
+    * Makefile.in (SUBDIR_PYTHON_SRCS): Add py-newobjfilevent.c.
+    (SUBDIR_PYTHON_OBS): Add py-newobjfileevent.o.
+    Add build rule for this file.
+    * python/py-event.h (emit_new_objfile_event): New prototype.
+    (newobjfile): New Python event emitter.
+    * python/py-evts.c (gdbpy_initialize_py_events): Add newobjfile to
+    Python event registry.
+    * python/py-inferior.c: Include objfiles.h
+    (python_new_objfile): New function.
+    (gdbpy_initialize_inferior): Add python_new_objfile to the new objfile
+    observers.
+    * python/py-newobjfileevent.c: New file.
+    * python-internal.h (gdbpy_initialize_new_objfile_event): New
+    prototype.
+    (gdbpy_current_objfile): New global variable.
+    * python/python.c (gdbpy_current_objfile): Make global.
+    (_initialize_python): Add gdbpy_initialize_new_objfile_event call.
+    * testsuite/gdb.python/py-events-shlib.c: New file.
+    * testsuite/gdb.python/py-events.c (do_nothing): New global.
+    (main): Add call to shared library.
+    * testsuite/gdb.python/py-events.exp: Link the execfile to a shared
+    library and check newobjfile event notification.
+    * testsuite/gdb.python/py-events.py (new_objfile_handler): New Class.
+    (test_newobj_events): New class.
+
2011-03-28  Jan Kratochvil  <jan.kratochvil@redhat.com>

Support resolution of STT_GNU_IFUNC via breakpoints.
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 489b1e9..3b79087 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -296,7 +296,8 @@ SUBDIR_PYTHON_OBS = \
py-threadevent.o \
py-type.o \
py-utils.o \
-    py-value.o
+    py-value.o \
+    py-newobjfileevent.o

SUBDIR_PYTHON_SRCS = \
python/python.c \
@@ -326,7 +327,8 @@ SUBDIR_PYTHON_SRCS = \
python/py-threadevent.c \
python/py-type.c \
python/py-utils.c \
-    python/py-value.c
+    python/py-value.c \
+    python/py-newobjfileevent.c
SUBDIR_PYTHON_DEPS =
SUBDIR_PYTHON_LDFLAGS=
SUBDIR_PYTHON_CFLAGS=
@@ -2110,6 +2112,11 @@ py-value.o: $(srcdir)/python/py-value.c
$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-value.c
$(POSTCOMPILE)

+py-newobjfileevent.o: $(srcdir)/python/py-newobjfileevent.c
+    $(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-newobjfileevent.c
+    $(POSTCOMPILE)
+
+
#
# Dependency tracking.  Most of this is conditional on GNU Make being
# found by configure; if GNU Make is not found, we fall back to a
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index a4e976f..360ff51 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -22057,6 +22057,12 @@ Emits @code{gdb.SignalEvent} which extends
@code{gdb.StopEvent}.
This event indicates that the inferior or one of its threads has received as
signal.  @code{gdb.SignalEvent} has the following attributes:

+@item events.newobjfile
+Emits @code{gdb.NewObjFileEvent} which indicates that a new object-file has
+been loaded in the inferior.
+
+During the callback, ``current objfile'' will be set to the new object file.
+
@table @code
@defivar SignalEvent stop_signal
A string representing the signal received by the inferior.  A list of possible
@@ -22699,10 +22705,10 @@ The following objfile-related functions are
available in the

@findex gdb.current_objfile
@defun current_objfile
-When auto-loading a Python script (@pxref{Auto-loading}), @value{GDBN}
-sets the ``current objfile'' to the corresponding objfile.  This
-function returns the current objfile.  If there is no current objfile,
-this function returns @code{None}.
+When auto-loading a Python script (@pxref{Auto-loading}) and during new
+object-file callbacks, @value{GDBN} sets the ``current objfile'' to the
+corresponding objfile.  This function returns the current objfile.  If
+there is no current objfile, this function returns @code{None}.
@end defun

@findex gdb.objfiles
diff --git a/gdb/python/py-event.h b/gdb/python/py-event.h
index bc95521..9a3ba82 100644
--- a/gdb/python/py-event.h
+++ b/gdb/python/py-event.h
@@ -105,6 +105,7 @@ typedef struct

extern int emit_continue_event (ptid_t ptid);
extern int emit_exited_event (LONGEST exit_code);
+extern int emit_new_objfile_event (struct objfile *objfile);

extern int evpy_emit_event (PyObject *event,
eventregistry_object *registry);
diff --git a/gdb/python/py-events.h b/gdb/python/py-events.h
index 6d4dae5..9c42e39 100644
--- a/gdb/python/py-events.h
+++ b/gdb/python/py-events.h
@@ -45,6 +45,7 @@ typedef struct
eventregistry_object *stop;
eventregistry_object *cont;
eventregistry_object *exited;
+  eventregistry_object *newobjfile;

PyObject *module;

diff --git a/gdb/python/py-evts.c b/gdb/python/py-evts.c
index 50c05f3..ee60560 100644
--- a/gdb/python/py-evts.c
+++ b/gdb/python/py-evts.c
@@ -57,6 +57,9 @@ gdbpy_initialize_py_events (void)

if (add_new_registry (&gdb_py_events.exited, "exited") < 0)
goto fail;
+
+  if (add_new_registry (&gdb_py_events.newobjfile, "newobjfile") < 0)
+    goto fail;

Py_INCREF (gdb_py_events.module);
if (PyModule_AddObject (gdb_module,
diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
index b9df394..ebd2a2a 100644
--- a/gdb/python/py-inferior.c
+++ b/gdb/python/py-inferior.c
@@ -22,6 +22,7 @@
#include "gdbcore.h"
#include "gdbthread.h"
#include "inferior.h"
+#include "objfiles.h"
#include "observer.h"
#include "python-internal.h"
#include "arch-utils.h"
@@ -129,6 +130,31 @@ python_inferior_exit (struct inferior *inf)
do_cleanups (cleanup);
}

+/* Callback used to notify Python listeners about new objfiles loaded in the
+   inferior. Python global variable 'gdb.current_objfile ()' will be set
+   during the notifications.
+ */
+
+static void
+python_new_objfile (struct objfile *objfile)
+{
+  struct cleanup *cleanup;
+
+  /* Will be NULL when clearing the symtab. */
+  if (objfile)
+    cleanup = ensure_python_env (get_objfile_arch (objfile), current_language);
+  else
+    cleanup = ensure_python_env (get_current_arch (), current_language);
+
+  gdbpy_current_objfile = objfile;
+
+  if (emit_new_objfile_event (objfile) < 0)
+    gdbpy_print_stack ();
+
+  do_cleanups (cleanup);
+  gdbpy_current_objfile = NULL;
+}
+
/* Return a borrowed reference to the Python object of type Inferior
representing INFERIOR.  If the object has already been created,
return it,  otherwise, create it.  Return NULL on failure.  */
@@ -669,6 +695,7 @@ gdbpy_initialize_inferior (void)
observer_attach_normal_stop (python_on_normal_stop);
observer_attach_target_resumed (python_on_resume);
observer_attach_inferior_exit (python_inferior_exit);
+  observer_attach_new_objfile (python_new_objfile);

if (PyType_Ready (&membuf_object_type) < 0)
return;
diff --git a/gdb/python/py-newobjfileevent.c b/gdb/python/py-newobjfileevent.c
new file mode 100644
index 0000000..20e2b31
--- /dev/null
+++ b/gdb/python/py-newobjfileevent.c
@@ -0,0 +1,53 @@
+/* Python interface to new object file loading events.
+
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "py-event.h"
+
+static PyTypeObject new_objfile_event_object_type;
+
+PyObject *
+create_new_objfile_event_object (void)
+{
+  return create_event_object (&new_objfile_event_object_type);
+}
+
+/* Callback function which notifies observers when a new objfile event occurs.
+   This function will create a new Python new_objfile event object.
+   Return -1 if emit fails.  */
+
+int
+emit_new_objfile_event (struct objfile *objfile)
+{
+  PyObject *event;
+
+  if (evregpy_no_listeners_p (gdb_py_events.newobjfile))
+    return 0;
+
+  event = create_new_objfile_event_object ();
+  if (event)
+    return evpy_emit_event (event, gdb_py_events.newobjfile);
+  return -1;
+}
+
+GDBPY_NEW_EVENT_TYPE (new_objfile,
+                      "gdb.NewObjFileEvent",
+                      "NewObjFileEvent",
+                      "GDB new object file event object",
+                      event_object_type,
+                      static);
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index d3cb788..cc9108f 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -207,6 +207,7 @@ void gdbpy_initialize_breakpoint_event (void);
void gdbpy_initialize_continue_event (void);
void gdbpy_initialize_exited_event (void);
void gdbpy_initialize_thread_event (void);
+void gdbpy_initialize_new_objfile_event (void);

struct cleanup *make_cleanup_py_decref (PyObject *py);

@@ -215,6 +216,7 @@ struct cleanup *ensure_python_env (struct gdbarch *gdbarch,

extern struct gdbarch *python_gdbarch;
extern const struct language_defn *python_language;
+extern struct objfile *gdbpy_current_objfile;

/* Use this after a TRY_EXCEPT to throw the appropriate Python
exception.  */
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 90d5dc8..df883ef 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -811,8 +811,9 @@ gdbpy_progspaces (PyObject *unused1, PyObject *unused2)

/* The "current" objfile.  This is set when gdb detects that a new
objfile has been loaded.  It is only set for the duration of a call to
-   source_python_script_for_objfile; it is NULL at other times.  */
-static struct objfile *gdbpy_current_objfile;
+   source_python_script_for_objfile and new_objfile callbacks; it is NULL at
+   other times.  */
+struct objfile *gdbpy_current_objfile;

/* Set the current objfile to OBJFILE and then read STREAM,FILE as
Python code.  */
@@ -1074,6 +1075,7 @@ Enables or disables printing of Python stack traces."),
gdbpy_initialize_continue_event ();
gdbpy_initialize_exited_event ();
gdbpy_initialize_thread_event ();
+  gdbpy_initialize_new_objfile_event () ;

PyRun_SimpleString ("import gdb");
PyRun_SimpleString ("gdb.pretty_printers = []");
diff --git a/gdb/testsuite/gdb.python/py-events-shlib.c
b/gdb/testsuite/gdb.python/py-events-shlib.c
new file mode 100644
index 0000000..2a17bbf
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-events-shlib.c
@@ -0,0 +1,20 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2011 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+
+void do_nothing (void) {}
+
diff --git a/gdb/testsuite/gdb.python/py-events.c
b/gdb/testsuite/gdb.python/py-events.c
index ceb697e..1cf7cc7 100644
--- a/gdb/testsuite/gdb.python/py-events.c
+++ b/gdb/testsuite/gdb.python/py-events.c
@@ -16,6 +16,8 @@
along with this program.  If not, see  <http://www.gnu.org/licenses/>.
*/

+extern void do_nothing (void) ;
+
int second(){
return 12;
}
@@ -25,5 +27,6 @@ int first(){
}

int main (){
+  do_nothing() ;
return first();
}
diff --git a/gdb/testsuite/gdb.python/py-events.exp
b/gdb/testsuite/gdb.python/py-events.exp
index e5d6daf..56e8f86 100644
--- a/gdb/testsuite/gdb.python/py-events.exp
+++ b/gdb/testsuite/gdb.python/py-events.exp
@@ -24,23 +24,45 @@ if $tracelevel then {

load_lib gdb-python.exp

+set libfile "py-events-shlib"
+set libsrc  $srcdir/$subdir/$libfile.c
+set lib_sl  $objdir/$subdir/$libfile.so
+set lib_opts  debug
+
set testfile "py-events"
set srcfile ${testfile}.c
set binfile ${objdir}/${subdir}/${testfile}
+set exec_opts [list debug shlib=$lib_sl]
set pyfile ${srcdir}/${subdir}/${testfile}.py

-if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
+if [get_compiler_info ${binfile}] {
+    return -1
+}
+
+if { [gdb_compile_shlib $libsrc $lib_sl $lib_opts] != ""
+     || [gdb_compile $srcdir/$subdir/$srcfile $binfile executable
$exec_opts] != ""} {
+    untested "Could not compile either $libsrc or $srcdir/$subdir/$srcfile."
return -1
}

+# Start with a fresh gdb.
+
+gdb_exit
+gdb_start
+
if { [skip_python_tests] } { continue }

+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
gdb_test_no_output "python execfile ('${pyfile}')" ""

-if ![runto_main ] then {
-    fail "Can't run to main"
-    return -1
-}
+gdb_test "Test_Newobj_Events" "New ObjectFile Event tester registered."
+
+gdb_breakpoint "main" {temporary}
+
+gdb_test "run" ".*event type: new_objfile.*
+.*new objfile name.*"

gdb_test "Test_Events" "Event testers registered."

diff --git a/gdb/testsuite/gdb.python/py-events.py
b/gdb/testsuite/gdb.python/py-events.py
index 9f05b9f..12e36e8 100644
--- a/gdb/testsuite/gdb.python/py-events.py
+++ b/gdb/testsuite/gdb.python/py-events.py
@@ -48,6 +48,14 @@ def continue_handler (event):
if ( event.inferior_thread is not None) :
print "thread num: %s" % (event.inferior_thread.num);

+def new_objfile_handler (event):
+    if (isinstance (event, gdb.NewObjFileEvent)):
+        print "event type: new_objfile"
+    if (gdb.current_objfile () is not None):
+        print "new objfile name: %s" % (gdb.current_objfile ().filename)
+    else:
+        print "new objfile is None"
+
class test_events (gdb.Command):
"""Test events."""

@@ -62,3 +70,15 @@ class test_events (gdb.Command):
print "Event testers registered."

test_events ()
+
+class test_newobj_events (gdb.Command):
+    """NewObj events."""
+
+    def __init__ (self):
+        gdb.Command.__init__ (self, "test_newobj_events", gdb.COMMAND_STACK)
+
+    def invoke (self, arg, from_tty):
+        gdb.events.newobjfile.connect (new_objfile_handler)
+        print "New ObjectFile Event tester registered."
+
+test_newobj_events ()
--
1.7.4

On Tue, Mar 29, 2011 at 4:21 AM, Kevin Pouget <kevin.pouget@gmail.com> wrote:
>
> Hello,
>
>
> > Do you have copyright assignment paperwork in place?  If not, let me
> > know and I can get you started.  This is a requirement before we can
> > accept a non-trivial patch.
>
> No, not yet, what I am supposed to ?
>
> > Kevin> and, likewise, allows Python's "gdb.current_objfile ()" to return
> > Kevin> the current object file.
> >
> > I'm ambivalent about this part.
> >
> > It seems to me that the objfile should be an attribute of the event.
> > Also setting it globally is ok, if you really want that, but it isn't a
> > necessity.
>
> I was ambivalent about this point too; I chose "gdb.current_objfile
> ()" because autoloading
> (http://sourceware.org/gdb/current/onlinedocs/gdb/Auto_002dloading.html)
> already does it this way, and the two features are pretty similar. I
> felt that it would have been strange to access "gdb.current_objfile
> ()" in one case, and sth like "event.new_objfile" in the other case
>
> let me know if you agree with this perspective; it wouldn't be a big
> deal to flip to the other solution otherwise
>
> > Kevin> There is still one thing I'm not happy with in the code, it's how to
> > Kevin> 'properly' access "gdbpy_current_objfile" ? I commented out "static"
> > Kevin> and declared it "extern" when I needed it, but that's certainly not
> > Kevin> the best way:
> >
> > Dropping the `static' is ok.  GDB is already full of this kind of thing.
> >
> > Kevin> +extern struct objfile *gdbpy_current_objfile;
> >
> > Should be in python-internal.h.
>
> fixed
>
> > Kevin> +static void
> > Kevin> +python_new_objfile (struct objfile *objfile)
> >
> > New functions need an introductory comment.
> >
> > Kevin> +  /* Will be NULL when clearing the symtab. */
> > Kevin> +  if (objfile)
> > Kevin> +    cleanup = ensure_python_env (get_objfile_arch (objfile), current_language);
> >
> > Is this comment stale?  It doesn't seem relevant.  When can objfile==NULL?
>
> I've been _once_ notified with NULL objfiles, coming from
> >> gdb/symfile.c:clear_symtab_users "observer_notify_new_objfile (NULL);"
>
> that's why I added the null-checking, but I didn't investigate what's
> behind this 'clear_symtab_users' and assumed
> 'observer_notify_new_objfile (NULL)' justifies the verification by
> itself
>
> is it okay for you?
>
> > Kevin> -
> > Kevin> +  observer_attach_new_objfile (python_new_objfile);
> > Kevin> +
> >
> > Gratuitous whitespace change.
>
> removed
>
> > Kevin> int
> > Kevin> emit_new_objfile_event (struct objfile *objfile)
> > Kevin> {
> > Kevin>   PyObject *event;
> > [...]
> > Kevin>   event = create_new_objfile_event_object ();
> > Kevin>   if (event)
> > Kevin>     return evpy_emit_event (event, gdb_py_events.newobjfile);
> > Kevin>   return -1;
> >
> > I think this should attach the objfile to the event object.
>
> that's discussed above, I'm waiting for your point of view
>
> * I added to the patch a few lines of documentation and updated the
> python event test-case. The exec is now linked with a shared-library
> automatically created, so that we know that the new objfile observers
> have to be notified. I'm not 100% confident about the test-case
> protocol, please don't hesitate to tell me if it's not resilient
> enough
>
> * I don't know how to add gdb/python/py-newobjfileevent.c and
> gdb/testsuite/gdb.python/py-events-shlib.c to the CVS diff, I'll move
> to git today so it should be fixed for the next patchs I send ; they
> are at the bottom of the mail, separated with '----'
>
> * I don't know if there is an 'automatic' way to update the ChangeLog
> (based on CVS/GIT), or if I should do it manually ?
>
>
> Cheers,
>
> Kevin
>
>
> ----
>
> ? gdb/python/py-newobjfileevent.c
> ? gdb/testsuite/gdb.python/py-events-shlib.c
> Index: gdb/Makefile.in
> ===================================================================
> RCS file: /cvs/src/src/gdb/Makefile.in,v
> retrieving revision 1.1163
> diff -u -r1.1163 Makefile.in
> --- gdb/Makefile.in     9 Mar 2011 06:10:37 -0000       1.1163
> +++ gdb/Makefile.in     29 Mar 2011 08:08:41 -0000
> @@ -296,7 +296,8 @@
>        py-threadevent.o \
>        py-type.o \
>        py-utils.o \
> -       py-value.o
> +       py-value.o \
> +       py-newobjfileevent.o
>
>  SUBDIR_PYTHON_SRCS = \
>        python/python.c \
> @@ -326,7 +327,8 @@
>        python/py-threadevent.c \
>        python/py-type.c \
>        python/py-utils.c \
> -       python/py-value.c
> +       python/py-value.c \
> +       python/py-newobjfileevent.c
>  SUBDIR_PYTHON_DEPS =
>  SUBDIR_PYTHON_LDFLAGS=
>  SUBDIR_PYTHON_CFLAGS=
> @@ -2110,6 +2112,11 @@
>        $(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-value.c
>        $(POSTCOMPILE)
>
> +py-newobjfileevent.o: $(srcdir)/python/py-newobjfileevent.c
> +       $(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-newobjfileevent.c
> +       $(POSTCOMPILE)
> +
> +
>  #
>  # Dependency tracking.  Most of this is conditional on GNU Make being
>  # found by configure; if GNU Make is not found, we fall back to a
> Index: gdb/doc/gdb.texinfo
> ===================================================================
> RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
> retrieving revision 1.814
> diff -u -r1.814 gdb.texinfo
> --- gdb/doc/gdb.texinfo 18 Mar 2011 08:44:46 -0000      1.814
> +++ gdb/doc/gdb.texinfo 29 Mar 2011 08:08:45 -0000
> @@ -22054,6 +22054,12 @@
>  This event indicates that the inferior or one of its threads has received as
>  signal.  @code{gdb.SignalEvent} has the following attributes:
>
> +@item events.newobjfile
> +Emits @code{gdb.NewObjFileEvent} which indicates that a new object-file has
> +been loaded in the inferior.
> +
> +During the callback, ``current objfile'' will be set to the new object file.
> +
>  @table @code
>  @defivar SignalEvent stop_signal
>  A string representing the signal received by the inferior.  A list of possible
> @@ -22696,10 +22702,10 @@
>
>  @findex gdb.current_objfile
>  @defun current_objfile
> -When auto-loading a Python script (@pxref{Auto-loading}), @value{GDBN}
> -sets the ``current objfile'' to the corresponding objfile.  This
> -function returns the current objfile.  If there is no current objfile,
> -this function returns @code{None}.
> +When auto-loading a Python script (@pxref{Auto-loading}) and during new
> +object-file callbacks, @value{GDBN} sets the ``current objfile'' to the
> +corresponding objfile.  This function returns the current objfile.  If
> +there is no current objfile, this function returns @code{None}.
>  @end defun
>
>  @findex gdb.objfiles
> Index: gdb/python/py-event.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/python/py-event.h,v
> retrieving revision 1.1
> diff -u -r1.1 py-event.h
> --- gdb/python/py-event.h       5 Feb 2011 05:27:23 -0000       1.1
> +++ gdb/python/py-event.h       29 Mar 2011 08:08:46 -0000
> @@ -105,6 +105,7 @@
>
>  extern int emit_continue_event (ptid_t ptid);
>  extern int emit_exited_event (LONGEST exit_code);
> +extern int emit_new_objfile_event (struct objfile *objfile);
>
>  extern int evpy_emit_event (PyObject *event,
>                             eventregistry_object *registry);
> Index: gdb/python/py-events.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/python/py-events.h,v
> retrieving revision 1.1
> diff -u -r1.1 py-events.h
> --- gdb/python/py-events.h      5 Feb 2011 05:27:23 -0000       1.1
> +++ gdb/python/py-events.h      29 Mar 2011 08:08:46 -0000
> @@ -45,6 +45,7 @@
>   eventregistry_object *stop;
>   eventregistry_object *cont;
>   eventregistry_object *exited;
> +  eventregistry_object *newobjfile;
>
>   PyObject *module;
>
> Index: gdb/python/py-evts.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/python/py-evts.c,v
> retrieving revision 1.2
> diff -u -r1.2 py-evts.c
> --- gdb/python/py-evts.c        14 Mar 2011 15:43:51 -0000      1.2
> +++ gdb/python/py-evts.c        29 Mar 2011 08:08:46 -0000
> @@ -57,6 +57,9 @@
>
>   if (add_new_registry (&gdb_py_events.exited, "exited") < 0)
>     goto fail;
> +
> +  if (add_new_registry (&gdb_py_events.newobjfile, "newobjfile") < 0)
> +    goto fail;
>
>   Py_INCREF (gdb_py_events.module);
>   if (PyModule_AddObject (gdb_module,
> Index: gdb/python/py-inferior.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/python/py-inferior.c,v
> retrieving revision 1.7
> diff -u -r1.7 py-inferior.c
> --- gdb/python/py-inferior.c    17 Mar 2011 09:36:16 -0000      1.7
> +++ gdb/python/py-inferior.c    29 Mar 2011 08:08:46 -0000
> @@ -22,6 +22,7 @@
>  #include "gdbcore.h"
>  #include "gdbthread.h"
>  #include "inferior.h"
> +#include "objfiles.h"
>  #include "observer.h"
>  #include "python-internal.h"
>  #include "arch-utils.h"
> @@ -129,6 +130,31 @@
>   do_cleanups (cleanup);
>  }
>
> +/* Callback used to notify Python listeners about new objfiles loaded in the
> +   inferior. Python global variable 'gdb.current_objfile ()' will be set
> +   during the notifications.
> + */
> +
> +static void
> +python_new_objfile (struct objfile *objfile)
> +{
> +  struct cleanup *cleanup;
> +
> +  /* Will be NULL when clearing the symtab. */
> +  if (objfile)
> +    cleanup = ensure_python_env (get_objfile_arch (objfile), current_language);
> +  else
> +    cleanup = ensure_python_env (get_current_arch (), current_language);
> +
> +  gdbpy_current_objfile = objfile;
> +
> +  if (emit_new_objfile_event (objfile) < 0)
> +    gdbpy_print_stack ();
> +
> +  do_cleanups (cleanup);
> +  gdbpy_current_objfile = NULL;
> +}
> +
>  /* Return a borrowed reference to the Python object of type Inferior
>    representing INFERIOR.  If the object has already been created,
>    return it,  otherwise, create it.  Return NULL on failure.  */
> @@ -669,6 +695,7 @@
>   observer_attach_normal_stop (python_on_normal_stop);
>   observer_attach_target_resumed (python_on_resume);
>   observer_attach_inferior_exit (python_inferior_exit);
> +  observer_attach_new_objfile (python_new_objfile);
>
>   if (PyType_Ready (&membuf_object_type) < 0)
>     return;
> Index: gdb/python/python-internal.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/python/python-internal.h,v
> retrieving revision 1.44
> diff -u -r1.44 python-internal.h
> --- gdb/python/python-internal.h        28 Feb 2011 19:38:34 -0000      1.44
> +++ gdb/python/python-internal.h        29 Mar 2011 08:08:46 -0000
> @@ -207,6 +207,7 @@
>  void gdbpy_initialize_continue_event (void);
>  void gdbpy_initialize_exited_event (void);
>  void gdbpy_initialize_thread_event (void);
> +void gdbpy_initialize_new_objfile_event (void);
>
>  struct cleanup *make_cleanup_py_decref (PyObject *py);
>
> @@ -215,6 +216,7 @@
>
>  extern struct gdbarch *python_gdbarch;
>  extern const struct language_defn *python_language;
> +extern struct objfile *gdbpy_current_objfile;
>
>  /* Use this after a TRY_EXCEPT to throw the appropriate Python
>    exception.  */
> Index: gdb/python/python.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/python/python.c,v
> retrieving revision 1.63
> diff -u -r1.63 python.c
> --- gdb/python/python.c 18 Mar 2011 08:44:47 -0000      1.63
> +++ gdb/python/python.c 29 Mar 2011 08:08:46 -0000
> @@ -811,8 +811,9 @@
>
>  /* The "current" objfile.  This is set when gdb detects that a new
>    objfile has been loaded.  It is only set for the duration of a call to
> -   source_python_script_for_objfile; it is NULL at other times.  */
> -static struct objfile *gdbpy_current_objfile;
> +   source_python_script_for_objfile and new_objfile callbacks; it is NULL at
> +   other times.  */
> +struct objfile *gdbpy_current_objfile;
>
>  /* Set the current objfile to OBJFILE and then read STREAM,FILE as
>    Python code.  */
> @@ -1074,6 +1075,7 @@
>   gdbpy_initialize_continue_event ();
>   gdbpy_initialize_exited_event ();
>   gdbpy_initialize_thread_event ();
> +  gdbpy_initialize_new_objfile_event () ;
>
>   PyRun_SimpleString ("import gdb");
>   PyRun_SimpleString ("gdb.pretty_printers = []");
> Index: gdb/testsuite/gdb.python/py-events.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/testsuite/gdb.python/py-events.c,v
> retrieving revision 1.1
> diff -u -r1.1 py-events.c
> --- gdb/testsuite/gdb.python/py-events.c        5 Feb 2011 05:27:23 -0000       1.1
> +++ gdb/testsuite/gdb.python/py-events.c        29 Mar 2011 08:08:46 -0000
> @@ -16,6 +16,8 @@
>    along with this program.  If not, see  <http://www.gnu.org/licenses/>.
>  */
>
> +extern void do_nothing (void) ;
> +
>  int second(){
>   return 12;
>  }
> @@ -25,5 +27,6 @@
>  }
>
>  int main (){
> +  do_nothing() ;
>   return first();
>  }
> Index: gdb/testsuite/gdb.python/py-events.exp
> ===================================================================
> RCS file: /cvs/src/src/gdb/testsuite/gdb.python/py-events.exp,v
> retrieving revision 1.1
> diff -u -r1.1 py-events.exp
> --- gdb/testsuite/gdb.python/py-events.exp      5 Feb 2011 05:27:23 -0000       1.1
> +++ gdb/testsuite/gdb.python/py-events.exp      29 Mar 2011 08:08:46 -0000
> @@ -24,23 +24,45 @@
>
>  load_lib gdb-python.exp
>
> +set libfile "py-events-shlib"
> +set libsrc  $srcdir/$subdir/$libfile.c
> +set lib_sl  $objdir/$subdir/$libfile.so
> +set lib_opts  debug
> +
>  set testfile "py-events"
>  set srcfile ${testfile}.c
>  set binfile ${objdir}/${subdir}/${testfile}
> +set exec_opts [list debug shlib=$lib_sl]
>  set pyfile ${srcdir}/${subdir}/${testfile}.py
>
> -if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
> +if [get_compiler_info ${binfile}] {
> +    return -1
> +}
> +
> +if { [gdb_compile_shlib $libsrc $lib_sl $lib_opts] != ""
> +     || [gdb_compile $srcdir/$subdir/$srcfile $binfile executable
> $exec_opts] != ""} {
> +    untested "Could not compile either $libsrc or $srcdir/$subdir/$srcfile."
>     return -1
>  }
>
> +# Start with a fresh gdb.
> +
> +gdb_exit
> +gdb_start
> +
>  if { [skip_python_tests] } { continue }
>
> +gdb_reinitialize_dir $srcdir/$subdir
> +gdb_load ${binfile}
> +
>  gdb_test_no_output "python execfile ('${pyfile}')" ""
>
> -if ![runto_main ] then {
> -    fail "Can't run to main"
> -    return -1
> -}
> +gdb_test "Test_Newobj_Events" "New ObjectFile Event tester registered."
> +
> +gdb_breakpoint "main" {temporary}
> +
> +gdb_test "run" ".*event type: new_objfile.*
> +.*new objfile name.*"
>
>  gdb_test "Test_Events" "Event testers registered."
>
> Index: gdb/testsuite/gdb.python/py-events.py
> ===================================================================
> RCS file: /cvs/src/src/gdb/testsuite/gdb.python/py-events.py,v
> retrieving revision 1.1
> diff -u -r1.1 py-events.py
> --- gdb/testsuite/gdb.python/py-events.py       5 Feb 2011 05:27:23 -0000       1.1
> +++ gdb/testsuite/gdb.python/py-events.py       29 Mar 2011 08:08:46 -0000
> @@ -48,6 +48,14 @@
>     if ( event.inferior_thread is not None) :
>         print "thread num: %s" % (event.inferior_thread.num);
>
> +def new_objfile_handler (event):
> +    if (isinstance (event, gdb.NewObjFileEvent)):
> +        print "event type: new_objfile"
> +    if (gdb.current_objfile () is not None):
> +       print "new objfile name: %s" % (gdb.current_objfile ().filename)
> +    else:
> +        print "new objfile is None"
> +
>  class test_events (gdb.Command):
>     """Test events."""
>
> @@ -62,3 +70,15 @@
>         print "Event testers registered."
>
>  test_events ()
> +
> +class test_newobj_events (gdb.Command):
> +    """NewObj events."""
> +
> +    def __init__ (self):
> +        gdb.Command.__init__ (self, "test_newobj_events", gdb.COMMAND_STACK)
> +
> +    def invoke (self, arg, from_tty):
> +        gdb.events.newobjfile.connect (new_objfile_handler)
> +        print "New ObjectFile Event tester registered."
> +
> +test_newobj_events ()
>
> ----
>
> /* Python interface to new object file loading events.
>
>   Copyright (C) 2011 Free Software Foundation, Inc.
>
>   This file is part of GDB.
>
>   This program is free software; you can redistribute it and/or modify
>   it under the terms of the GNU General Public License as published by
>   the Free Software Foundation; either version 3 of the License, or
>   (at your option) any later version.
>
>   This program is distributed in the hope that it will be useful,
>   but WITHOUT ANY WARRANTY; without even the implied warranty of
>   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>   GNU General Public License for more details.
>
>   You should have received a copy of the GNU General Public License
>   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
>
> #include "py-event.h"
>
> static PyTypeObject new_objfile_event_object_type;
>
> PyObject *
> create_new_objfile_event_object (void)
> {
>  return create_event_object (&new_objfile_event_object_type);
> }
>
> /* Callback function which notifies observers when a new objfile event occurs.
>   This function will create a new Python new_objfile event object.
>   Return -1 if emit fails.  */
>
> int
> emit_new_objfile_event (struct objfile *objfile)
> {
>  PyObject *event;
>
>  if (evregpy_no_listeners_p (gdb_py_events.newobjfile))
>    return 0;
>
>  event = create_new_objfile_event_object ();
>  if (event)
>    return evpy_emit_event (event, gdb_py_events.newobjfile);
>  return -1;
> }
>
> GDBPY_NEW_EVENT_TYPE (new_objfile,
>                      "gdb.NewObjFileEvent",
>                      "NewObjFileEvent",
>                      "GDB new object file event object",
>                      event_object_type,
>                      static);
>
> ----
>
> /* This testcase is part of GDB, the GNU debugger.
>
>   Copyright 2011 Free Software Foundation, Inc.
>
>   This program is free software; you can redistribute it and/or modify
>   it under the terms of the GNU General Public License as published by
>   the Free Software Foundation; either version 3 of the License, or
>   (at your option) any later version.
>
>   This program is distributed in the hope that it will be useful,
>   but WITHOUT ANY WARRANTY; without even the implied warranty of
>   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>   GNU General Public License for more details.
>
>   You should have received a copy of the GNU General Public License
>   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
>
>
> void do_nothing (void) {}