Re: [PATCH v8] Events when inferior is modified

[Nick Bull <nicholaspbull at gmail dot com>]

On 17/11/14 21:24, Doug Evans wrote:
> Hi.
> 
> Let's go with ptids.

Doug,

Thanks. So is this version of the patch now good to apply?  Note that I don't have
push access so will need someone to commit it on my behalf.

Thanks

Nick



> 
> On Mon, Nov 17, 2014 at 10:13 AM, Nick Bull <nicholaspbull@gmail.com> wrote:
>> Ping.
>>
>> The discussion on exposing ptids vs GDB thread numbers looks to have ended without a clear
>> conclusion. This patch uses ptids - is it OK?
>>
>> Thanks
>>
>> Nick
>>
>> On 22/10/14 13:40, Nick Bull wrote:
>>>
>>>
>>> On 17/10/14 21:00, Doug Evans wrote:
>>>> Doug Evans writes:
>>>>     > [...]
>>>
>>>
>>> Hi Doug,
>>>
>>> Thanks for looking through the patch. I believe this version addresses everything you mentioned.
>>>
>>> Nick
>>>
>>>
>>> gdb/ChangeLog
>>>
>>> 2014-05-15  Nick Bull  <nicholaspbull@gmail.com>
>>>
>>>        * NEWS: Mention new Python events.
>>>        * Makefile.in: add py-infcallevent.c / py-infcallevent.o.
>>>        * doc/observer.texi (inferior_call_pre, inferior_call_post)
>>>        (memory_changed, register_changed): New observers.
>>>        * infcall.c (call_function_by_hand): Notify observer before and
>>>        after inferior call.
>>>        * python/py-event.h (inferior_call_kind): New enum.
>>>        (emit_inferior_call_event): New prototype.
>>>        (emit_register_changed_event): New prototype.
>>>        (emit_memory_changed_event): New prototype.
>>>        * python/py-events.h (events_object): New registries
>>>        inferior_call, memory_changed and register_changed.
>>>        * python/py-evts.c (gdbpy_initialize_py_events): Add the
>>>        inferior_call, memory_changed and register_changed registries.
>>>        * python/py-infcallevent.c: New.
>>>        * python/py-inferior.c (python_on_inferior_call_pre)
>>>        (python_on_inferior_call_post, python_on_register_change)
>>>        (python_on_memory_change): New functions.
>>>        (gdbpy_initialize_inferior): Attach python handler to new
>>>        observers.
>>>        * python/py-infthread.c:
>>>        (gdbpy_create_ptid_object): New.
>>>        (thpy_get_ptid) Use gdbpy_create_ptid_object.
>>>        * python/python-internal.h:
>>>        (gdbpy_create_ptid_object)
>>>        (gdbpy_initialize_inferior_call_pre_event)
>>>        (gdbpy_initialize_inferior_call_post_event)
>>>        (gdbpy_initialize_register_changed_event)
>>>        (gdbpy_initialize_memory_changed_event): New prototypes.
>>>        * python/python.c (_initialize_python): Initialize new events.
>>>        * valops.c (value_assign): Notify register_changed observer.
>>>
>>> gdb/doc/ChangeLog
>>>
>>> 2014-05-15  Nick Bull  <nicholaspbull@gmail.com>
>>>
>>>        * python.texi (Events In Python): Document new events
>>>        InferiorCallPreEvent, InferiorCallPostEvent, MemoryChangedEvent
>>>        and RegisterChangedEvent.
>>>
>>> gdb/testsuite/ChangeLog
>>>
>>> 2014-05-15  Nick Bull  <nicholaspbull@gmail.com>
>>>
>>>        * gdb.python/py-events.py (inferior_fn_handler): New.
>>>        (register_changed_handler, memory_changed_handler): New.
>>>        (test_events.invoke): Register new handlers.
>>>        * gdb.python/py-events.exp: Add tests for inferior call,
>>>        memory_changed and register_changed events.
>>>
>>>
>>> diff --git a/gdb/Makefile.in b/gdb/Makefile.in
>>> index 1ffa62a..9a913d8 100644
>>> --- a/gdb/Makefile.in
>>> +++ b/gdb/Makefile.in
>>> @@ -360,6 +360,7 @@ SUBDIR_PYTHON_OBS = \
>>>        py-framefilter.o \
>>>        py-function.o \
>>>        py-gdb-readline.o \
>>> +     py-infcallevent.o \
>>>        py-inferior.o \
>>>        py-infthread.o \
>>>        py-lazy-string.o \
>>> @@ -398,6 +399,7 @@ SUBDIR_PYTHON_SRCS = \
>>>        python/py-framefilter.c \
>>>        python/py-function.c \
>>>        python/py-gdb-readline.c \
>>> +     python/py-infcallevent.c \
>>>        python/py-inferior.c \
>>>        python/py-infthread.c \
>>>        python/py-lazy-string.c \
>>> @@ -2477,6 +2479,10 @@ py-gdb-readline.o: $(srcdir)/python/py-gdb-readline.c
>>>        $(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-gdb-readline.c
>>>        $(POSTCOMPILE)
>>>
>>> +py-infcallevent.o: $(srcdir)/python/py-infcallevent.c
>>> +     $(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-infcallevent.c
>>> +     $(POSTCOMPILE)
>>> +
>>>    py-inferior.o: $(srcdir)/python/py-inferior.c
>>>        $(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-inferior.c
>>>        $(POSTCOMPILE)
>>> diff --git a/gdb/NEWS b/gdb/NEWS
>>> index b56fe8e..3445634 100644
>>> --- a/gdb/NEWS
>>> +++ b/gdb/NEWS
>>> @@ -1,6 +1,16 @@
>>>                What has changed in GDB?
>>>             (Organized release by release)
>>>
>>> +* Python Scripting
>>> +
>>> +  New events which are triggered when GDB modifies the state of the
>>> +  inferior.
>>> +
>>> +  ** gdb.events.inferior_call_pre: Function call is about to be made.
>>> +  ** gdb.events.inferior_call_post: Function call has just been made.
>>> +  ** gdb.events.memory_changed: A memory location has been altered.
>>> +  ** gdb.events.register_changed: A register has been altered.
>>> +
>>>    *** Changes since GDB 7.8
>>>
>>>    * GDB now supports hardware watchpoints on x86 GNU Hurd.
>>> diff --git a/gdb/doc/observer.texi b/gdb/doc/observer.texi
>>> index 2757587..7c4af6b 100644
>>> --- a/gdb/doc/observer.texi
>>> +++ b/gdb/doc/observer.texi
>>> @@ -281,6 +281,22 @@ The trace state variable @var{tsv} is deleted.  If @var{tsv} is
>>>    The trace state value @var{tsv} is modified.
>>>    @end deftypefun
>>>
>>> +@deftypefun void inferior_call_pre (ptid_t @var{thread}, CORE_ADDR @var{address})
>>> +An inferior function at @var{address} is about to be called in thread
>>> +@var{thread}.
>>> +@end deftypefun
>>> +
>>> +@deftypefun void inferior_call_post (ptid_t @var{thread}, CORE_ADDR @var{address})
>>> +The inferior function at @var{address} has just been called.  This observer
>>> +is called even if the inferior exits during the call.  @var{thread} is the
>>> +thread in which the function was called, which may be different from the
>>> +current thread.
>>> +@end deftypefun
>>> +
>>> +@deftypefun void register_changed (struct frame_info *@var{frame}, int @var{regnum})
>>> +A register in the inferior has been modified by the @value{GDBN} user.
>>> +@end deftypefun
>>> +
>>>    @deftypefun void test_notification (int @var{somearg})
>>>    This observer is used for internal testing.  Do not use.
>>>    See testsuite/gdb.gdb/observer.exp.
>>> diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
>>> index 81ec11b..d2376f6 100644
>>> --- a/gdb/doc/python.texi
>>> +++ b/gdb/doc/python.texi
>>> @@ -2728,6 +2728,55 @@ 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
>>>
>>> +@item events.inferior_call_pre
>>> +Emits @code{gdb.InferiorCallPreEvent} which indicates that a function in
>>> +the inferior is about to be called.
>>> +
>>> +@defvar InferiorCallPreEvent.ptid
>>> +The thread in which the call will be run.
>>> +@end defvar
>>> +
>>> +@defvar InferiorCallPreEvent.address
>>> +The location of the function to be called.
>>> +@end defvar
>>> +
>>> +@item events.inferior_call_post
>>> +Emits @code{gdb.InferiorCallPostEvent} which indicates that a function in
>>> +the inferior has returned.
>>> +
>>> +@defvar InferiorCallPostEvent.ptid
>>> +The thread in which the call was run.
>>> +@end defvar
>>> +
>>> +@defvar InferiorCallPostEvent.address
>>> +The location of the function that was called.
>>> +@end defvar
>>> +
>>> +@item events.memory_changed
>>> +Emits @code{gdb.MemoryChangedEvent} which indicates that the memory of the
>>> +inferior has been modified by the @value{GDBN} user, for instance via a
>>> +command like @w{@code{set *addr = value}}.  The event has the following
>>> +attributes:
>>> +
>>> +@defvar MemoryChangedEvent.address
>>> +The start address of the changed region.
>>> +@end defvar
>>> +
>>> +@defvar MemoryChangedEvent.length
>>> +Length in bytes of the changed region.
>>> +@end defvar
>>> +
>>> +@item events.register_changed
>>> +Emits @code{gdb.RegisterChangedEvent} which indicates that a register in the
>>> +inferior has been modified by the @value{GDBN} user.
>>> +
>>> +@defvar RegisterChangedEvent.frame
>>> +A gdb.Frame object representing the frame in which the register was modified.
>>> +@end defvar
>>> +@defvar RegisterChangedEvent.regnum
>>> +Denotes which register was modified.
>>> +@end defvar
>>> +
>>>    @end table
>>>
>>>    @node Threads In Python
>>> diff --git a/gdb/infcall.c b/gdb/infcall.c
>>> index e60d1d4..d390fbe 100644
>>> --- a/gdb/infcall.c
>>> +++ b/gdb/infcall.c
>>> @@ -36,6 +36,7 @@
>>>    #include "gdbthread.h"
>>>    #include "exceptions.h"
>>>    #include "event-top.h"
>>> +#include "observer.h"
>>>
>>>    /* If we can't find a function's name from its address,
>>>       we print this instead.  */
>>> @@ -627,6 +628,8 @@ call_function_by_hand (struct value *function, int nargs, struct value **args)
>>>          target_values_type = values_type;
>>>        }
>>>
>>> +  observer_notify_inferior_call_pre (inferior_ptid, funaddr);
>>> +
>>>      /* Determine the location of the breakpoint (and possibly other
>>>         stuff) that the called function will return to.  The SPARC, for a
>>>         function returning a structure or union, needs to make space for
>>> @@ -860,6 +863,8 @@ call_function_by_hand (struct value *function, int nargs, struct value **args)
>>>        e = run_inferior_call (tp, real_pc);
>>>      }
>>>
>>> +  observer_notify_inferior_call_post (call_thread_ptid, funaddr);
>>> +
>>>      /* Rethrow an error if we got one trying to run the inferior.  */
>>>
>>>      if (e.reason < 0)
>>> diff --git a/gdb/python/py-event.h b/gdb/python/py-event.h
>>> index 5a0f29b..4a7d58a 100644
>>> --- a/gdb/python/py-event.h
>>> +++ b/gdb/python/py-event.h
>>> @@ -105,6 +105,22 @@ typedef struct
>>>    extern int emit_continue_event (ptid_t ptid);
>>>    extern int emit_exited_event (const LONGEST *exit_code, struct inferior *inf);
>>>
>>> +/* For inferior function call events, discriminate whether event is
>>> +   before or after the call. */
>>> +
>>> +typedef enum
>>> +{
>>> +  /* Before the call */
>>> +  INFERIOR_CALL_PRE,
>>> +  /* after the call */
>>> +  INFERIOR_CALL_POST,
>>> +} inferior_call_kind;
>>> +
>>> +extern int emit_inferior_call_event (inferior_call_kind kind,
>>> +                                  ptid_t thread, CORE_ADDR addr);
>>> +extern int emit_register_changed_event (struct frame_info *frame,
>>> +                                     int regnum);
>>> +extern int emit_memory_changed_event (CORE_ADDR addr, ssize_t len);
>>>    extern int evpy_emit_event (PyObject *event,
>>>                                eventregistry_object *registry)
>>>      CPYCHECKER_STEALS_REFERENCE_TO_ARG (1);
>>> diff --git a/gdb/python/py-events.h b/gdb/python/py-events.h
>>> index 3431612..e219305 100644
>>> --- a/gdb/python/py-events.h
>>> +++ b/gdb/python/py-events.h
>>> @@ -46,6 +46,9 @@ typedef struct
>>>      eventregistry_object *cont;
>>>      eventregistry_object *exited;
>>>      eventregistry_object *new_objfile;
>>> +  eventregistry_object *inferior_call;
>>> +  eventregistry_object *memory_changed;
>>> +  eventregistry_object *register_changed;
>>>
>>>      PyObject *module;
>>>
>>> diff --git a/gdb/python/py-evts.c b/gdb/python/py-evts.c
>>> index a7daf8a..1825464 100644
>>> --- a/gdb/python/py-evts.c
>>> +++ b/gdb/python/py-evts.c
>>> @@ -73,6 +73,18 @@ gdbpy_initialize_py_events (void)
>>>      if (add_new_registry (&gdb_py_events.exited, "exited") < 0)
>>>        return -1;
>>>
>>> +  if (add_new_registry (&gdb_py_events.inferior_call,
>>> +                     "inferior_call") < 0)
>>> +    return -1;
>>> +
>>> +  if (add_new_registry (&gdb_py_events.memory_changed,
>>> +                     "memory_changed") < 0)
>>> +    return -1;
>>> +
>>> +  if (add_new_registry (&gdb_py_events.register_changed,
>>> +                     "register_changed") < 0)
>>> +    return -1;
>>> +
>>>      if (add_new_registry (&gdb_py_events.new_objfile, "new_objfile") < 0)
>>>        return -1;
>>>
>>> diff --git a/gdb/python/py-infcallevent.c b/gdb/python/py-infcallevent.c
>>> new file mode 100644
>>> index 0000000..d688b81
>>> --- /dev/null
>>> +++ b/gdb/python/py-infcallevent.c
>>> @@ -0,0 +1,265 @@
>>> +/* Python interface to inferior function events.
>>> +
>>> +   Copyright (C) 2013 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 "defs.h"
>>> +#include "py-event.h"
>>> +
>>> +static PyTypeObject inferior_call_pre_event_object_type
>>> +    CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("event_object");
>>> +static PyTypeObject inferior_call_post_event_object_type
>>> +    CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("event_object");
>>> +static PyTypeObject register_changed_event_object_type
>>> +    CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("event_object");
>>> +static PyTypeObject memory_changed_event_object_type
>>> +    CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("event_object");
>>> +
>>> +/* Construct either a gdb.InferiorCallPreEvent or a
>>> +   gdb.InferiorCallPostEvent. */
>>> +
>>> +static PyObject *
>>> +create_inferior_call_event_object (inferior_call_kind flag, ptid_t ptid,
>>> +                                CORE_ADDR addr)
>>> +{
>>> +  int pid;
>>> +  long tid, lwp;
>>> +  PyObject * event;
>>> +  PyObject *ptid_obj = NULL;
>>> +  PyObject *addr_obj = NULL;
>>> +  int failed;
>>> +  struct cleanup *cleanups;
>>> +  struct cleanup *member_cleanups;
>>> +
>>> +  switch (flag)
>>> +    {
>>> +    case INFERIOR_CALL_PRE:
>>> +      event = create_event_object (&inferior_call_pre_event_object_type);
>>> +      break;
>>> +    case INFERIOR_CALL_POST:
>>> +      event = create_event_object (&inferior_call_post_event_object_type);
>>> +      break;
>>> +    default:
>>> +      return NULL;
>>> +    }
>>> +
>>> +  cleanups = make_cleanup_py_decref (event);
>>> +
>>> +  ptid_obj = gdbpy_create_ptid_object (ptid);
>>> +
>>> +  if (!ptid_obj)
>>> +    goto fail;
>>> +
>>> +  member_cleanups = make_cleanup_py_decref (ptid_obj);
>>> +
>>> +  failed = evpy_add_attribute (event, "ptid", ptid_obj) < 0;
>>> +  if (failed)
>>> +    goto fail;
>>> +
>>> +  addr_obj = PyLong_FromLongLong (addr);
>>> +  if (addr_obj == NULL)
>>> +    goto fail;
>>> +  make_cleanup_py_decref (addr_obj);
>>> +
>>> +  failed = evpy_add_attribute (event, "address", addr_obj) < 0;
>>> +  if (failed)
>>> +    goto fail;
>>> +
>>> +  do_cleanups (member_cleanups);
>>> +  discard_cleanups (cleanups);
>>> +  return event;
>>> +
>>> + fail:
>>> +  do_cleanups (cleanups);
>>> +  return NULL;
>>> +}
>>> +
>>> +/* Construct a gdb.RegisterChangedEvent containing the affected
>>> +   register number. */
>>> +
>>> +static PyObject *
>>> +create_register_changed_event_object (struct frame_info *frame,
>>> +                                   int regnum)
>>> +{
>>> +  PyObject * event;
>>> +  PyObject *frame_obj = NULL;
>>> +  PyObject *regnum_obj = NULL;
>>> +  int failed;
>>> +  struct cleanup *cleanups;
>>> +  struct cleanup *member_cleanups;
>>> +
>>> +  event = create_event_object (&register_changed_event_object_type);
>>> +  if (event == NULL)
>>> +    return NULL;
>>> +
>>> +  cleanups = make_cleanup_py_decref (event);
>>> +
>>> +  frame_obj = frame_info_to_frame_object (frame);
>>> +  if (frame_obj == NULL)
>>> +    goto fail;
>>> +  member_cleanups = make_cleanup_py_decref (frame_obj);
>>> +
>>> +  failed = evpy_add_attribute (event, "frame", frame_obj) < 0;
>>> +  if (failed)
>>> +    goto fail;
>>> +
>>> +  regnum_obj = PyLong_FromLongLong (regnum);
>>> +  if (regnum_obj == NULL)
>>> +    goto fail;
>>> +  make_cleanup_py_decref (regnum_obj);
>>> +
>>> +  failed = evpy_add_attribute (event, "regnum", regnum_obj) < 0;
>>> +  if (failed)
>>> +    goto fail;
>>> +
>>> +  do_cleanups (member_cleanups);
>>> +  discard_cleanups (cleanups);
>>> +  return event;
>>> +
>>> + fail:
>>> +  do_cleanups (cleanups);
>>> +  return NULL;
>>> +}
>>> +
>>> +/* Construct a gdb.MemoryChangedEvent describing the extent of the
>>> +   affected memory. */
>>> +
>>> +static PyObject *
>>> +create_memory_changed_event_object (CORE_ADDR addr, ssize_t len)
>>> +{
>>> +  PyObject *event;
>>> +  PyObject *addr_obj = NULL;
>>> +  PyObject *len_obj = NULL;
>>> +  int failed;
>>> +  struct cleanup *cleanups;
>>> +  struct cleanup *member_cleanups;
>>> +
>>> +  event = create_event_object (&memory_changed_event_object_type);
>>> +
>>> +  if (event == NULL)
>>> +    return NULL;
>>> +  cleanups = make_cleanup_py_decref (event);
>>> +
>>> +  addr_obj = PyLong_FromLongLong (addr);
>>> +  if (addr_obj == NULL)
>>> +    goto fail;
>>> +  member_cleanups = make_cleanup_py_decref (addr_obj);
>>> +
>>> +  failed = evpy_add_attribute (event, "address", addr_obj) < 0;
>>> +  if (failed)
>>> +    goto fail;
>>> +
>>> +  len_obj = PyLong_FromLong (len);
>>> +  if (len_obj == NULL)
>>> +    goto fail;
>>> +  make_cleanup_py_decref (len_obj);
>>> +
>>> +  failed = evpy_add_attribute (event, "length", len_obj) < 0;
>>> +  if (failed)
>>> +    goto fail;
>>> +
>>> +  do_cleanups (member_cleanups);
>>> +  discard_cleanups (cleanups);
>>> +  return event;
>>> +
>>> + fail:
>>> +  do_cleanups (cleanups);
>>> +  return NULL;
>>> +}
>>> +
>>> +/* Callback function which notifies observers when an event occurs which
>>> +   calls a function in the inferior.
>>> +   This function will create a new Python inferior-call event object.
>>> +   Return -1 if emit fails.  */
>>> +
>>> +int
>>> +emit_inferior_call_event (inferior_call_kind flag, ptid_t thread,
>>> +                       CORE_ADDR addr)
>>> +{
>>> +  PyObject *event;
>>> +
>>> +  if (evregpy_no_listeners_p (gdb_py_events.inferior_call))
>>> +    return 0;
>>> +
>>> +  event = create_inferior_call_event_object (flag, thread, addr);
>>> +  if (event != NULL)
>>> +    return evpy_emit_event (event, gdb_py_events.inferior_call);
>>> +  return -1;
>>> +}
>>> +
>>> +/* Callback when memory is modified by the user.  This function will
>>> +   create a new Python memory changed event object. */
>>> +
>>> +int
>>> +emit_memory_changed_event (CORE_ADDR addr, ssize_t len)
>>> +{
>>> +  PyObject *event;
>>> +
>>> +  if (evregpy_no_listeners_p (gdb_py_events.memory_changed))
>>> +    return 0;
>>> +
>>> +  event = create_memory_changed_event_object (addr, len);
>>> +  if (event != NULL)
>>> +    return evpy_emit_event (event, gdb_py_events.memory_changed);
>>> +  return -1;
>>> +}
>>> +
>>> +/* Callback when a register is modified by the user.  This function
>>> +   will create a new Python register changed event object. */
>>> +
>>> +int
>>> +emit_register_changed_event (struct frame_info* frame, int regnum)
>>> +{
>>> +  PyObject *event;
>>> +
>>> +  if (evregpy_no_listeners_p (gdb_py_events.register_changed))
>>> +    return 0;
>>> +
>>> +  event = create_register_changed_event_object (frame, regnum);
>>> +  if (event != NULL)
>>> +    return evpy_emit_event (event, gdb_py_events.register_changed);
>>> +  return -1;
>>> +}
>>> +
>>> +
>>> +GDBPY_NEW_EVENT_TYPE (inferior_call_pre,
>>> +                   "gdb.InferiorCallPreEvent",
>>> +                   "InferiorCallPreEvent",
>>> +                   "GDB inferior function pre-call event object",
>>> +                   event_object_type,
>>> +                   static);
>>> +
>>> +GDBPY_NEW_EVENT_TYPE (inferior_call_post,
>>> +                   "gdb.InferiorCallPostEvent",
>>> +                   "InferiorCallPostEvent",
>>> +                   "GDB inferior function post-call event object",
>>> +                   event_object_type,
>>> +                   static);
>>> +
>>> +GDBPY_NEW_EVENT_TYPE (register_changed,
>>> +                   "gdb.RegisterChangedEvent",
>>> +                   "RegisterChangedEvent",
>>> +                   "GDB register change event object",
>>> +                   event_object_type,
>>> +                   static);
>>> +
>>> +GDBPY_NEW_EVENT_TYPE (memory_changed,
>>> +                   "gdb.MemoryChangedEvent",
>>> +                   "MemoryChangedEvent",
>>> +                   "GDB memory change event object",
>>> +                   event_object_type,
>>> +                   static);
>>> diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
>>> index 9b8b8f5..f22c343 100644
>>> --- a/gdb/python/py-inferior.c
>>> +++ b/gdb/python/py-inferior.c
>>> @@ -117,6 +117,72 @@ python_on_resume (ptid_t ptid)
>>>      do_cleanups (cleanup);
>>>    }
>>>
>>> +/* Callback, registered as an observer, that notifies Python listeners
>>> +   when an inferior function call is about to be made. */
>>> +
>>> +static void
>>> +python_on_inferior_call_pre (ptid_t thread, CORE_ADDR address)
>>> +{
>>> +  struct cleanup *cleanup;
>>> +
>>> +  cleanup = ensure_python_env (target_gdbarch (), current_language);
>>> +
>>> +  if (emit_inferior_call_event (INFERIOR_CALL_PRE, thread, address) < 0)
>>> +    gdbpy_print_stack ();
>>> +
>>> +  do_cleanups (cleanup);
>>> +}
>>> +
>>> +/* Callback, registered as an observer, that notifies Python listeners
>>> +   when an inferior function call has completed. */
>>> +
>>> +static void
>>> +python_on_inferior_call_post (ptid_t thread, CORE_ADDR address)
>>> +{
>>> +  struct cleanup *cleanup;
>>> +
>>> +  cleanup = ensure_python_env (target_gdbarch (), current_language);
>>> +
>>> +  if (emit_inferior_call_event (INFERIOR_CALL_POST, thread, address) < 0)
>>> +    gdbpy_print_stack ();
>>> +
>>> +  do_cleanups (cleanup);
>>> +}
>>> +
>>> +/* Callback, registered as an observer, that notifies Python listeners
>>> +   when a part of memory has been modified by user action (eg via a
>>> +   'set' command). */
>>> +
>>> +static void
>>> +python_on_memory_change (struct inferior *inferior, CORE_ADDR addr, ssize_t len, const bfd_byte *data)
>>> +{
>>> +  struct cleanup *cleanup;
>>> +
>>> +  cleanup = ensure_python_env (target_gdbarch (), current_language);
>>> +
>>> +  if (emit_memory_changed_event (addr, len) < 0)
>>> +    gdbpy_print_stack ();
>>> +
>>> +  do_cleanups (cleanup);
>>> +}
>>> +
>>> +/* Callback, registered as an observer, that notifies Python listeners
>>> +   when a register has been modified by user action (eg via a 'set'
>>> +   command). */
>>> +
>>> +static void
>>> +python_on_register_change (struct frame_info *frame, int regnum)
>>> +{
>>> +  struct cleanup *cleanup;
>>> +
>>> +  cleanup = ensure_python_env (target_gdbarch (), current_language);
>>> +
>>> +  if (emit_register_changed_event (frame, regnum) < 0)
>>> +    gdbpy_print_stack ();
>>> +
>>> +  do_cleanups (cleanup);
>>> +}
>>> +
>>>    static void
>>>    python_inferior_exit (struct inferior *inf)
>>>    {
>>> @@ -794,6 +860,10 @@ gdbpy_initialize_inferior (void)
>>>      observer_attach_thread_exit (delete_thread_object);
>>>      observer_attach_normal_stop (python_on_normal_stop);
>>>      observer_attach_target_resumed (python_on_resume);
>>> +  observer_attach_inferior_call_pre (python_on_inferior_call_pre);
>>> +  observer_attach_inferior_call_post (python_on_inferior_call_post);
>>> +  observer_attach_memory_changed (python_on_memory_change);
>>> +  observer_attach_register_changed (python_on_register_change);
>>>      observer_attach_inferior_exit (python_inferior_exit);
>>>      observer_attach_new_objfile (python_new_objfile);
>>>
>>> diff --git a/gdb/python/py-infthread.c b/gdb/python/py-infthread.c
>>> index e03cbd9..74570bc 100644
>>> --- a/gdb/python/py-infthread.c
>>> +++ b/gdb/python/py-infthread.c
>>> @@ -138,23 +138,10 @@ thpy_get_ptid (PyObject *self, void *closure)
>>>      int pid;
>>>      long tid, lwp;
>>>      thread_object *thread_obj = (thread_object *) self;
>>> -  PyObject *ret;
>>>
>>>      THPY_REQUIRE_VALID (thread_obj);
>>>
>>> -  ret = PyTuple_New (3);
>>> -  if (!ret)
>>> -    return NULL;
>>> -
>>> -  pid = ptid_get_pid (thread_obj->thread->ptid);
>>> -  lwp = ptid_get_lwp (thread_obj->thread->ptid);
>>> -  tid = ptid_get_tid (thread_obj->thread->ptid);
>>> -
>>> -  PyTuple_SET_ITEM (ret, 0, PyInt_FromLong (pid));
>>> -  PyTuple_SET_ITEM (ret, 1, PyInt_FromLong (lwp));
>>> -  PyTuple_SET_ITEM (ret, 2, PyInt_FromLong (tid));
>>> -
>>> -  return ret;
>>> +  return gdbpy_create_ptid_object (thread_obj->thread->ptid);
>>>    }
>>>
>>>    /* Implementation of InferiorThread.switch ().
>>> @@ -236,6 +223,30 @@ thpy_is_valid (PyObject *self, PyObject *args)
>>>      Py_RETURN_TRUE;
>>>    }
>>>
>>> +/* Return a reference to a new Python object representing a ptid_t.
>>> +   The object is a tuple containing (pid, lwp, tid). */
>>> +PyObject *
>>> +gdbpy_create_ptid_object (ptid_t ptid)
>>> +{
>>> +  int pid;
>>> +  long tid, lwp;
>>> +  PyObject *ret;
>>> +
>>> +  ret = PyTuple_New (3);
>>> +  if (!ret)
>>> +    return NULL;
>>> +
>>> +  pid = ptid_get_pid (ptid);
>>> +  lwp = ptid_get_lwp (ptid);
>>> +  tid = ptid_get_tid (ptid);
>>> +
>>> +  PyTuple_SET_ITEM (ret, 0, PyInt_FromLong (pid));
>>> +  PyTuple_SET_ITEM (ret, 1, PyInt_FromLong (lwp));
>>> +  PyTuple_SET_ITEM (ret, 2, PyInt_FromLong (tid));
>>> +
>>> +  return ret;
>>> +}
>>> +
>>>    /* Implementation of gdb.selected_thread () -> gdb.InferiorThread.
>>>       Returns the selected thread object.  */
>>>    PyObject *
>>> diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
>>> index 6e7e600..9c7bc53 100644
>>> --- a/gdb/python/python-internal.h
>>> +++ b/gdb/python/python-internal.h
>>> @@ -365,6 +365,7 @@ PyObject *gdbpy_create_lazy_string_object (CORE_ADDR address, long length,
>>>                                           const char *encoding,
>>>                                           struct type *type);
>>>    PyObject *gdbpy_inferiors (PyObject *unused, PyObject *unused2);
>>> +PyObject *gdbpy_create_ptid_object (ptid_t ptid);
>>>    PyObject *gdbpy_selected_thread (PyObject *self, PyObject *args);
>>>    PyObject *gdbpy_selected_inferior (PyObject *self, PyObject *args);
>>>    PyObject *gdbpy_string_to_argv (PyObject *self, PyObject *args);
>>> @@ -466,6 +467,14 @@ int gdbpy_initialize_breakpoint_event (void)
>>>      CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
>>>    int gdbpy_initialize_continue_event (void)
>>>      CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
>>> +int gdbpy_initialize_inferior_call_pre_event (void)
>>> +  CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
>>> +int gdbpy_initialize_inferior_call_post_event (void)
>>> +  CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
>>> +int gdbpy_initialize_register_changed_event (void)
>>> +  CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
>>> +int gdbpy_initialize_memory_changed_event (void)
>>> +  CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
>>>    int gdbpy_initialize_exited_event (void)
>>>      CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
>>>    int gdbpy_initialize_thread_event (void)
>>> diff --git a/gdb/python/python.c b/gdb/python/python.c
>>> index 40c4ec9..68e3af8 100644
>>> --- a/gdb/python/python.c
>>> +++ b/gdb/python/python.c
>>> @@ -1754,6 +1754,10 @@ message == an error message without a stack will be printed."),
>>>          || gdbpy_initialize_signal_event () < 0
>>>          || gdbpy_initialize_breakpoint_event () < 0
>>>          || gdbpy_initialize_continue_event () < 0
>>> +      || gdbpy_initialize_inferior_call_pre_event () < 0
>>> +      || gdbpy_initialize_inferior_call_post_event () < 0
>>> +      || gdbpy_initialize_register_changed_event () < 0
>>> +      || gdbpy_initialize_memory_changed_event () < 0
>>>          || gdbpy_initialize_exited_event () < 0
>>>          || gdbpy_initialize_thread_event () < 0
>>>          || gdbpy_initialize_new_objfile_event ()  < 0
>>> diff --git a/gdb/testsuite/gdb.python/py-events.exp b/gdb/testsuite/gdb.python/py-events.exp
>>> index 92de550..aa702b7 100644
>>> --- a/gdb/testsuite/gdb.python/py-events.exp
>>> +++ b/gdb/testsuite/gdb.python/py-events.exp
>>> @@ -79,6 +79,123 @@ all threads stopped"
>>>
>>>    delete_breakpoints
>>>
>>> +# Test inferior call events
>>> +
>>> +gdb_test_multiple "info threads" "get current thread" {
>>> +    -re "\[^\n\r\]*process (\[0-9\]+)\[^\n\r\]*do_nothing.*$gdb_prompt $" {
>>> +     set process_id $expect_out(1,string)
>>> +     pass "get current thread"
>>> +    }
>>> +}
>>> +
>>> +gdb_test_multiple "print do_nothing" "get address of do_nothing" {
>>> +    -re "\[^\n\r\]*(0x\[0-9a-f\]+) \<do_nothing\>.*$gdb_prompt $" {
>>> +     set addr $expect_out(1,string)
>>> +     pass "get address of do_nothing"
>>> +    }
>>> +}
>>> +
>>> +set expected [list "event type: pre-call"]
>>> +lappend expected "ptid: \\($process_id, $process_id, 0\\)" "address: $addr"
>>> +lappend expected "event type: post-call"
>>> +lappend expected "ptid: \\($process_id, $process_id, 0\\)" "address: $addr"
>>> +gdb_test_sequence "call do_nothing()" "" $expected
>>> +
>>> +# Test register changed event
>>> +gdb_test_no_output {set $old_sp = $sp}
>>> +gdb_test_sequence {set $sp = 0} "" {
>>> +    "event type: register-changed"
>>> +    "frame: "
>>> +    "num: "
>>> +}
>>> +gdb_test_sequence {set $sp = 1} "" {
>>> +    "event type: register-changed"
>>> +    "frame: "
>>> +    "num: "
>>> +}
>>> +gdb_test_sequence {set $sp = $old_sp} "" {
>>> +    "event type: register-changed"
>>> +    "frame: "
>>> +    "num: "
>>> +}
>>> +
>>> +# Test that no register_changed event is generated on "non-user"
>>> +# modifications
>>> +set test "up"
>>> +gdb_test_multiple {up} $test {
>>> +    -re "event type: register-changed.*\r\n$gdb_prompt $" {
>>> +     fail $test
>>> +    }
>>> +    -re "#1.*in first.*\r\n.*do_nothing.*\r\n$gdb_prompt $" {
>>> +     pass $test
>>> +    }
>>> +}
>>> +
>>> +set test "down"
>>> +gdb_test_multiple {down} $test {
>>> +    -re "event type: register-changed.*\r\n$gdb_prompt $" {
>>> +     fail $test
>>> +    }
>>> +    -re "#0.*do_nothing.*at.*\r\n.*void do_nothing.*\r\n$gdb_prompt $" {
>>> +     pass $test
>>> +    }
>>> +}
>>> +
>>> +set test "step"
>>> +gdb_test_multiple {step} $test {
>>> +    -re "event type: register-changed.*\r\n$gdb_prompt $" {
>>> +     fail $test
>>> +    }
>>> +    -re "first.*at.*\r\n.*28.*for.*\r\n$gdb_prompt $" {
>>> +     pass $test
>>> +    }
>>> +}
>>> +
>>> +
>>> +# Test memory changed event
>>> +gdb_test_no_output {set $saved = *(int*) $sp}
>>> +gdb_test_sequence {set *(int*) $sp = 0} "" {
>>> +    "event type: memory-changed"
>>> +    "address: "
>>> +    "length: "
>>> +}
>>> +gdb_test_sequence {set *(int*) $sp = $saved} "" {
>>> +    "event type: memory-changed"
>>> +    "address: "
>>> +    "length: "
>>> +}
>>> +
>>> +# Test that no memory_changed event is generated on breakpoint
>>> +# activity
>>> +set test "break second"
>>> +gdb_test_multiple "break second" $test {
>>> +    -re "event type: memory-changed" {
>>> +     fail $test
>>> +    }
>>> +    -re "Breakpoint (\[0-9\]+) at .*\r\n$gdb_prompt $" {
>>> +     set second_breakpoint $expect_out(1,string)
>>> +     pass $test
>>> +    }
>>> +
>>> +}
>>> +
>>> +set test "continue to breakpoint $second_breakpoint"
>>> +set expected ".*event type: continue.*\r\n"
>>> +append expected ".*event type: stop.*\r\n"
>>> +append expected ".*stop reason: breakpoint.*\r\n"
>>> +append expected ".*all threads stopped.*\r\n$gdb_prompt $"
>>> +
>>> +gdb_test_multiple "continue" $test {
>>> +    -re "event type: memory-changed.*\r\n$gdb_prompt $" {
>>> +     fail $test
>>> +    }
>>> +    -re $expected {
>>> +     pass $test
>>> +    }
>>> +}
>>> +
>>> +gdb_test_no_output "delete $second_breakpoint"
>>> +
>>>    #test exited event.
>>>    gdb_test "continue" ".*event type: continue.*
>>>    .*event type: exit.*
>>> diff --git a/gdb/testsuite/gdb.python/py-events.py b/gdb/testsuite/gdb.python/py-events.py
>>> index 1f0012a..67c1aea 100644
>>> --- a/gdb/testsuite/gdb.python/py-events.py
>>> +++ b/gdb/testsuite/gdb.python/py-events.py
>>> @@ -57,6 +57,30 @@ def new_objfile_handler (event):
>>>        print ("event type: new_objfile")
>>>        print ("new objfile name: %s" % (event.new_objfile.filename))
>>>
>>> +def inferior_fn_handler (event):
>>> +    if (isinstance (event, gdb.InferiorCallPreEvent)):
>>> +        print ("event type: pre-call")
>>> +    elif (isinstance (event, gdb.InferiorCallPostEvent)):
>>> +        print ("event type: post-call")
>>> +    else:
>>> +        assert False
>>> +    print ("ptid: %s" % (event.ptid,))
>>> +    print ("address: 0x%x" % (event.address))
>>> +
>>> +def register_changed_handler (event):
>>> +    assert (isinstance (event, gdb.RegisterChangedEvent))
>>> +    print ("event type: register-changed")
>>> +    assert (isinstance (event.frame, gdb.Frame))
>>> +    print ("frame: %s" % (event.frame))
>>> +    print ("num: %s" % (event.regnum))
>>> +
>>> +def memory_changed_handler (event):
>>> +    assert (isinstance (event, gdb.MemoryChangedEvent))
>>> +    print ("event type: memory-changed")
>>> +    print ("address: %s" % (event.address))
>>> +    print ("length: %s" % (event.length))
>>> +
>>> +
>>>    class test_events (gdb.Command):
>>>        """Test events."""
>>>
>>> @@ -68,6 +92,9 @@ class test_events (gdb.Command):
>>>            gdb.events.stop.connect (breakpoint_stop_handler)
>>>            gdb.events.exited.connect (exit_handler)
>>>            gdb.events.cont.connect (continue_handler)
>>> +        gdb.events.inferior_call.connect (inferior_fn_handler)
>>> +        gdb.events.memory_changed.connect (memory_changed_handler)
>>> +        gdb.events.register_changed.connect (register_changed_handler)
>>>            print ("Event testers registered.")
>>>
>>>    test_events ()
>>> diff --git a/gdb/valops.c b/gdb/valops.c
>>> index f177907..d900e50 100644
>>> --- a/gdb/valops.c
>>> +++ b/gdb/valops.c
>>> @@ -1170,6 +1170,7 @@ value_assign (struct value *toval, struct value *fromval)
>>>              }
>>>          }
>>>
>>> +     observer_notify_register_changed (frame, value_reg);
>>>        if (deprecated_register_changed_hook)
>>>          deprecated_register_changed_hook (-1);
>>>        break;
>>>