[RFC - Python] New ObjFile event

Kevin Pouget kevin.pouget@gmail.com
Wed May 18 09:13:00 GMT 2011


Hello, I just notice that this patch wasn't completely accepted (by
the end of March),
so I re-post the patch with a correct format


Tom, what do you thing about the last corrections (cf. after the ChangeLog) ?


Cordially,

Kevin

--

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.

2011-03-29  Kevin Pouget  <kevin.pouget@st.com>

	Allow Python notification of new object-file loadings.
	* gdb.textinfo (Events In Python): Document `gdb.NewObjFileEvent'
	events emitter.
	(Objfiles In Python): Indicate that `gdb.current_objfile' is also set
	during new object-file callbacks.

--


>> 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> +  /* 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> 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
-------------- next part --------------
From 66553b17a7d2b64d24588ccf7e5364d6b06438b9 Mon Sep 17 00:00:00 2001
From: Kevin Pouget <kevin.pouget@st.com>
Date: Tue, 17 May 2011 10:18:35 -0400
Subject: [PATCH] Allow Python notification of new object-file loadings.

---
 gdb/Makefile.in                            |   10 ++++-
 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 ++++++++++
 13 files changed, 179 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/Makefile.in b/gdb/Makefile.in
index 5bab360..dfff210 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -301,7 +301,8 @@ 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 \
@@ -331,7 +332,8 @@ 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=
@@ -2130,6 +2132,10 @@ 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 67436dd..ecdfdf3 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -22139,6 +22139,12 @@ 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
@@ -22781,10 +22787,10 @@ 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..c8d1044 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, "newobjfile") < 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 b9df394..777979a 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 8a7bc66..c96984c 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 ()
-- 
1.7.4.4



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