Re: [RFC - Python] New ObjFile event

Kevin Pouget
2011-10-05T11:10:59Z

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On Tue, Oct 4, 2011 at 7:01 PM, Tom Tromey <tromey@redhat.com> wrote:
>
> >>>>> "Kevin" == Kevin Pouget <kevin.pouget@gmail.com> writes:
>
> Tom> Why not simply make the objfile object an attribute of the event?
> Tom> That seems cleaner to me.
>
> Kevin> We already discussed this point, but it was at the end of ... March :)
>
> Thanks for the reminder.
> I completely forgot about that.
>
> Kevin> I was ambivalent about this point too; I chose
> Kevin> "gdb.current_objfile()" because autoloading
> Kevin> (http://sourceware.org/gdb/current/onlinedocs/gdb/Auto_002dloading.html)
> Kevin> already does it this way, and the two features are pretty similar. I
> Kevin> felt that it would have been strange to access "gdb.current_objfile ()"
> Kevin> in one case, and sth like "event.new_objfile" in the other case
>
> Ok, I see.
>
> I think it is best to pass it as part of the event.
> It is ok with me if you also want to have it set the current objfile.
>
> Tom

I got rid of the "gdb.current_objfile ()" access to the objfile and
kept only the "NewObjFile.new_objfile" attribute of the Event object,
which indeed makes more sense.
I've updated the code and documentation accordingly; could you please
tell me if it seems good for you?

Thanks,

Kevin

2011-10-05 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 new_objfile 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.
* NEWS: Add item for new Python event "gdb.newobjfile"

2011-10-05 Kevin Pouget <kevin.pouget@st.com>

Allow Python notification of new object-file loadings.
* gdb.texinfo (Events In Python): Document `gdb.NewObjFileEvent'
event type.

2011-10-05 Kevin Pouget <kevin.pouget@st.com>

Allow Python notification of new object-file loadings.
* gdb.python/py-events.exp: Test newobjfile event.
* gdb.python/py-events.py: Register newobjfile callback.
* gdb.python/py-events.c: Add call to shared library
* gdb.python/py-events-shlib.c: New file.

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From 5984c89f5a5ae980c09daf942c9722b03fd0cd41 Mon Sep 17 00:00:00 2001
From: Kevin Pouget <kevin.pouget@st.com>
Date: Thu, 1 Sep 2011 11:08:23 +0200
Subject: [PATCH] New ObjFile event

---
gdb/Makefile.in | 6 ++
gdb/NEWS | 2 +
gdb/doc/gdb.texinfo | 11 ++++
gdb/python/py-event.h | 1 +
gdb/python/py-events.h | 1 +
gdb/python/py-evts.c | 3 +
gdb/python/py-inferior.c | 21 ++++++++
gdb/python/py-newobjfileevent.c | 70 ++++++++++++++++++++++++++++
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 | 26 ++++++++--
gdb/testsuite/gdb.python/py-events.py | 20 ++++++++
14 files changed, 185 insertions(+), 7 deletions(-)
create mode 100644 gdb/python/py-newobjfileevent.c
create mode 100644 gdb/testsuite/gdb.python/py-events-shlib.c

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 826d339..986588b 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -289,6 +289,7 @@ SUBDIR_PYTHON_OBS = \
py-inferior.o \
py-infthread.o \
py-lazy-string.o \
+ py-newobjfileevent.o \
py-objfile.o \
py-param.o \
py-prettyprint.o \
@@ -319,6 +320,7 @@ SUBDIR_PYTHON_SRCS = \
python/py-inferior.c \
python/py-infthread.c \
python/py-lazy-string.c \
+ python/py-newobjfileevent.c \
python/py-objfile.c \
python/py-param.c \
python/py-prettyprint.c \
@@ -2115,6 +2117,10 @@ py-lazy-string.o: $(srcdir)/python/py-lazy-string.c
$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-lazy-string.c
$(POSTCOMPILE)

+py-newobjfileevent.o: $(srcdir)/python/py-newobjfileevent.c
+ $(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-newobjfileevent.c
+ $(POSTCOMPILE)
+
py-objfile.o: $(srcdir)/python/py-objfile.c
$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-objfile.c
$(POSTCOMPILE)
diff --git a/gdb/NEWS b/gdb/NEWS
index 20e58a0..788498f 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -41,6 +41,8 @@
** The "gdb.breakpoint" function has been deprecated in favor of
"gdb.breakpoints".

+ ** A new event "gdb.newobjfile" has been added.
+
* libthread-db-search-path now supports two special values: $sdir and $pdir.
$sdir specifies the default system locations of shared libraries.
$pdir specifies the directory where the libpthread used by the application
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index dd0f7f6..5be090f 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -22358,6 +22358,17 @@ in favor of the @code{gdb.BreakpointEvent.breakpoints} attribute.
@end defvar
@end table

+@item events.new_objfile
+Emits @code{gdb.NewObjFileEvent} which indicates that a new object-file has
+been loaded by @value{GDBN}. @code{gdb.NewObjFileEvent} has one attribute:
+
+@table @code
+@defvar NewObjFileEvent.new_objfile
+A reference to the object file (@code{gdb.Objfile}) which has been loaded.
+@xref{Objfiles In Python}, for details of the @code{gdb.Objfile} object.
+@end defvar
+@end table
+
@end table

@node Threads In Python
diff --git a/gdb/python/py-event.h b/gdb/python/py-event.h
index 49d7b6a..716aabd 100644
--- a/gdb/python/py-event.h
+++ b/gdb/python/py-event.h
@@ -111,6 +111,7 @@ extern int evpy_emit_event (PyObject *event,

extern PyObject *create_event_object (PyTypeObject *py_type);
extern PyObject *create_thread_event_object (PyTypeObject *py_type);
+extern int emit_new_objfile_event (struct objfile *objfile);

extern void evpy_dealloc (PyObject *self);
extern int evpy_add_attribute (PyObject *event,
diff --git a/gdb/python/py-events.h b/gdb/python/py-events.h
index bd54418..70f45a4 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..c24a04c 100644
--- a/gdb/python/py-evts.c
+++ b/gdb/python/py-evts.c
@@ -58,6 +58,9 @@ 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, "new_objfile") < 0)
+ goto fail;
+
Py_INCREF (gdb_py_events.module);
if (PyModule_AddObject (gdb_module,
"events",
diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
index 275caea..afc3eb0 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"
@@ -125,6 +126,25 @@ python_inferior_exit (struct inferior *inf)
do_cleanups (cleanup);
}

+/* Callback used to notify Python listeners about new objfiles loaded in the
+ inferior. */
+
+static void
+python_new_objfile (struct objfile *objfile)
+{
+ struct cleanup *cleanup;
+
+ if (objfile == NULL)
+ return;
+
+ cleanup = ensure_python_env (get_objfile_arch (objfile), current_language);
+
+ if (emit_new_objfile_event (objfile) < 0)
+ gdbpy_print_stack ();
+
+ do_cleanups (cleanup);
+}
+
/* Return a reference to the Python object of type Inferior
representing INFERIOR. If the object has already been created,
return it and increment the reference count, otherwise, create it.
@@ -715,6 +735,7 @@ 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);

membuf_object_type.tp_new = PyType_GenericNew;
if (PyType_Ready (&membuf_object_type) < 0)
diff --git a/gdb/python/py-newobjfileevent.c b/gdb/python/py-newobjfileevent.c
new file mode 100644
index 0000000..e9716a6
--- /dev/null
+++ b/gdb/python/py-newobjfileevent.c
@@ -0,0 +1,70 @@
+/* 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 (struct objfile *objfile)
+{
+ PyObject *objfile_event;
+ PyObject *py_objfile;
+
+ objfile_event = create_event_object (&new_objfile_event_object_type);
+ if (!objfile_event)
+ goto fail;
+
+ py_objfile = objfile_to_objfile_object (objfile);
+ if (!py_objfile || evpy_add_attribute (objfile_event,
+ "new_objfile",
+ py_objfile) < 0)
+ goto fail;
+
+ return objfile_event;
+
+ fail:
+ Py_XDECREF (objfile_event);
+ return NULL;
+}
+
+/* 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 (objfile);
+ 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 bff40b5..31bccaa 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -214,6 +214,7 @@ 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);

@@ -222,6 +223,7 @@ 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 61c5420..f95995a 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -938,8 +938,9 @@ 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.
@@ -1257,6 +1258,7 @@ 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 () ;

observer_attach_before_prompt (before_prompt_hook);

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 665ca51..c20cc84 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(){
fork() ;
return 12;
@@ -26,5 +28,6 @@ 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 18419fa..e420389 100644
--- a/gdb/testsuite/gdb.python/py-events.exp
+++ b/gdb/testsuite/gdb.python/py-events.exp
@@ -19,23 +19,39 @@ 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.
+clean_restart ${testfile}
+
if { [skip_python_tests] } { continue }

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." "Register new objfile event handler"
+
+gdb_breakpoint "main" {temporary}
+
+gdb_test "run" ".*event type: new_objfile.*new objfile name.*" "New objfile notification"

gdb_test_no_output "set detach-on-fork off" ""

diff --git a/gdb/testsuite/gdb.python/py-events.py b/gdb/testsuite/gdb.python/py-events.py
index 6bdd935..ab549c4 100644
--- a/gdb/testsuite/gdb.python/py-events.py
+++ b/gdb/testsuite/gdb.python/py-events.py
@@ -51,6 +51,14 @@ 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 (event.new_objfile is not None):
+ print "new objfile name: %s" % (event.new_objfile.filename)
+ else:
+ print "new objfile is None"
+
class test_events (gdb.Command):
"""Test events."""

@@ -65,3 +73,15 @@ 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.new_objfile.connect (new_objfile_handler)
+ print "New ObjectFile Event tester registered."
+
+test_newobj_events ()
--
1.7.6.2