[RFA 1/3] Add new_inferior, inferior_deleted, and new_thread events

Tom Tromey
2017-09-09T00:34:05Z

This adds a few new events to gdb's Python layer: new_inferior,
inferior_deleted, and new_thread. I wanted to be able to add a
combined inferior/thread display window to my GUI, and I needed a few
events to make this work. This is PR python/15622.

gdb/ChangeLog
2017-09-08 Tom Tromey <tom@tromey.com>

PR python/15622:
* NEWS: Add entry.
* python/python.c (do_start_initialization): Initialize new event
types.
* python/python-internal.h (gdbpy_initialize_new_inferior_event)
(gdbpy_initialize_inferior_deleted_event)
(gdbpy_initialize_new_thread_event): Declare.
* python/py-threadevent.c (create_thread_event_object): Add option
"thread" parameter.
* python/py-inferior.c (new_thread_event_object_type)
(new_inferior_event_object_type)
(inferior_deleted_event_object_type): Declare.
(python_new_inferior, python_inferior_deleted): New functions.
(add_thread_object): Emit new_thread event.
(gdbpy_initialize_inferior): Attach new functions to corresponding
observers.
(new_thread, new_inferior, inferior_deleted): Define new event
types.
* python/py-evts.c (gdbpy_initialize_py_events): Add new
registries.
* python/py-events.h (events_object) <new_inferior,
inferior_deleted, new_thread>: New fields.
* python/py-event.h (create_thread_event_breakpoint): Add optional
"thread" parameter.

gdb/doc/ChangeLog
2017-09-08 Tom Tromey <tom@tromey.com>

* python.texi (Events In Python): Document new events.

gdb/testsuite/ChangeLog
2017-09-08 Tom Tromey <tom@tromey.com>

* gdb.python/py-infthread.exp: Add tests for new_thread event.
* gdb.python/py-inferior.exp: Add tests for new inferior events.
---
gdb/ChangeLog | 27 ++++++++++
gdb/NEWS | 6 +++
gdb/doc/ChangeLog | 6 ++-
gdb/doc/python.texi | 30 +++++++++++
gdb/python/py-event.h | 3 +-
gdb/python/py-events.h | 3 ++
gdb/python/py-evts.c | 9 ++++
gdb/python/py-inferior.c | 88 +++++++++++++++++++++++++++++++
gdb/python/py-threadevent.c | 13 ++---
gdb/python/python-internal.h | 6 +++
gdb/python/python.c | 3 ++
gdb/testsuite/ChangeLog | 5 ++
gdb/testsuite/gdb.python/py-inferior.exp | 24 +++++++++
gdb/testsuite/gdb.python/py-infthread.exp | 12 +++++
14 files changed, 227 insertions(+), 8 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 96369d5..88520ea 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,30 @@
+2017-09-08 Tom Tromey <tom@tromey.com>
+
+ PR python/15622:
+ * NEWS: Add entry.
+ * python/python.c (do_start_initialization): Initialize new event
+ types.
+ * python/python-internal.h (gdbpy_initialize_new_inferior_event)
+ (gdbpy_initialize_inferior_deleted_event)
+ (gdbpy_initialize_new_thread_event): Declare.
+ * python/py-threadevent.c (create_thread_event_object): Add option
+ "thread" parameter.
+ * python/py-inferior.c (new_thread_event_object_type)
+ (new_inferior_event_object_type)
+ (inferior_deleted_event_object_type): Declare.
+ (python_new_inferior, python_inferior_deleted): New functions.
+ (add_thread_object): Emit new_thread event.
+ (gdbpy_initialize_inferior): Attach new functions to corresponding
+ observers.
+ (new_thread, new_inferior, inferior_deleted): Define new event
+ types.
+ * python/py-evts.c (gdbpy_initialize_py_events): Add new
+ registries.
+ * python/py-events.h (events_object) <new_inferior,
+ inferior_deleted, new_thread>: New fields.
+ * python/py-event.h (create_thread_event_breakpoint): Add optional
+ "thread" parameter.
+
2017-09-08 Keith Seitz <keiths@redhat.com>

* dwarf2read.c (struct field_info) <fnfields>: Remove unused
diff --git a/gdb/NEWS b/gdb/NEWS
index f6ed614..2e6d48c 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -15,6 +15,12 @@
the remote inferior is started by the GDBserver, use the "unset
environment" command.

+* Python Scripting
+
+ ** New events gdb.new_inferior, gdb.inferior_deleted, and
+ gdb.new_thread are emitted. See the manual for further
+ description of these.
+
* New features in the GDB remote stub, GDBserver

** New "--selftest" command line option runs some GDBserver self
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 72f3d9e..65147f7 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@
+2017-09-08 Tom Tromey <tom@tromey.com>
+
+ * python.texi (Events In Python): Document new events.
+
2017-09-04 Pedro Alves <palves@redhat.com>

* gdb.texinfo (Variables) <Program Variables>: Document inspecting
@@ -12039,7 +12043,7 @@ Wed Feb 26 18:04:40 1992 K. Richard Pixley (rich@cygnus.com)

* Makefile.in, configure.in: removed traces of namesubdir,
-subdirs, $(subdir), $(unsubdir), some rcs triggers. Forced
- copyrights to '92, '13, changed some from Cygnus to FSF.
+ copyrights to '92, '13, '17, changed some from Cygnus to FSF.

Fri Dec 13 09:47:31 1991 John Gilmore (gnu at cygnus.com)

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 32d7939..83d078b 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -2989,6 +2989,36 @@ invalid state; that is, the @code{is_valid} method will return
This event carries no payload. It is emitted each time @value{GDBN}
presents a prompt to the user.

+@item events.new_inferior
+This is notified when a new inferior is created. Note that the
+inferior is not necessarily running; in fact, it may not even have an
+associated executable.
+
+The event is of type @code{gdb.NewInferiorEvent}. This has a single
+attribute:
+
+@defvar NewInferiorEvent.inferior
+The new inferior, a @code{gdb.Inferior} object.
+@end defvar
+
+@item events.inferior_deleted
+This is notified when an inferior has been deleted. Note that this is
+not the same as process exit; it is notified when the inferior itself
+is removed, say via @code{remove-inferiors}.
+
+The event is of type @code{gdb.InferiorDeletedEvent}. This has a single
+attribute:
+
+@defvar NewInferiorEvent.inferior
+The inferior that is being removed, a @code{gdb.Inferior} object.
+@end defvar
+
+@item events.new_thread
+This emitted when @value{GDBN} notices a new thread. The event is of
+type @code{gdb.NewThreadEvent}, which extends @code{gdb.ThreadEvent}.
+The @code{new_thread} event always sets the @code{inferior_thread}
+attribute on the event object, regardless of the non-stop setting.
+
@end table

@node Threads In Python
diff --git a/gdb/python/py-event.h b/gdb/python/py-event.h
index ccb8513..2f02c5f 100644
--- a/gdb/python/py-event.h
+++ b/gdb/python/py-event.h
@@ -125,7 +125,8 @@ extern int evpy_emit_event (PyObject *event,
eventregistry_object *registry);

extern PyObject *create_event_object (PyTypeObject *py_type);
-extern PyObject *create_thread_event_object (PyTypeObject *py_type);
+extern PyObject *create_thread_event_object (PyTypeObject *py_type,
+ PyObject *thread = nullptr);
extern int emit_new_objfile_event (struct objfile *objfile);
extern int emit_clear_objfiles_event (void);

diff --git a/gdb/python/py-events.h b/gdb/python/py-events.h
index 348dabc..2275d89 100644
--- a/gdb/python/py-events.h
+++ b/gdb/python/py-events.h
@@ -47,6 +47,9 @@ typedef struct
eventregistry_object *exited;
eventregistry_object *new_objfile;
eventregistry_object *clear_objfiles;
+ eventregistry_object *new_inferior;
+ eventregistry_object *inferior_deleted;
+ eventregistry_object *new_thread;
eventregistry_object *inferior_call;
eventregistry_object *memory_changed;
eventregistry_object *register_changed;
diff --git a/gdb/python/py-evts.c b/gdb/python/py-evts.c
index 126d18c..ad99241 100644
--- a/gdb/python/py-evts.c
+++ b/gdb/python/py-evts.c
@@ -89,6 +89,15 @@ gdbpy_initialize_py_events (void)
if (add_new_registry (&gdb_py_events.clear_objfiles, "clear_objfiles") < 0)
return -1;

+ if (add_new_registry (&gdb_py_events.new_inferior, "new_inferior") < 0)
+ return -1;
+
+ if (add_new_registry (&gdb_py_events.inferior_deleted, "inferior_deleted") < 0)
+ return -1;
+
+ if (add_new_registry (&gdb_py_events.new_thread, "new_thread") < 0)
+ return -1;
+
if (add_new_registry (&gdb_py_events.breakpoint_created,
"breakpoint_created") < 0)
return -1;
diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
index f6a24a0..d7c6810 100644
--- a/gdb/python/py-inferior.c
+++ b/gdb/python/py-inferior.c
@@ -30,6 +30,13 @@
#include "py-event.h"
#include "py-stopevent.h"

+extern PyTypeObject new_thread_event_object_type
+ CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("event_object");
+extern PyTypeObject new_inferior_event_object_type
+ CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("event_object");
+extern PyTypeObject inferior_deleted_event_object_type
+ CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("event_object");
+
struct threadlist_entry {
thread_object *thread_obj;
struct threadlist_entry *next;
@@ -235,6 +242,60 @@ inferior_to_inferior_object (struct inferior *inferior)
return (PyObject *) inf_obj;
}

+/* Called when a new inferior is created. Notifies any Python event
+ listeners. */
+static void
+python_new_inferior (struct inferior *inf)
+{
+ if (!gdb_python_initialized)
+ return;
+
+ gdbpy_enter enter_py (python_gdbarch, python_language);
+
+ if (evregpy_no_listeners_p (gdb_py_events.new_inferior))
+ return;
+
+ gdbpy_ref<> inf_obj (inferior_to_inferior_object (inf));
+ if (inf_obj == NULL)
+ {
+ gdbpy_print_stack ();
+ return;
+ }
+
+ gdbpy_ref<> event (create_event_object (&new_inferior_event_object_type));
+ if (event == NULL
+ || evpy_add_attribute (event.get (), "inferior", inf_obj.get ()) < 0
+ || evpy_emit_event (event.get (), gdb_py_events.new_inferior) < 0)
+ gdbpy_print_stack ();
+}
+
+/* Called when an inferior is removed. Notifies any Python event
+ listeners. */
+static void
+python_inferior_deleted (struct inferior *inf)
+{
+ if (!gdb_python_initialized)
+ return;
+
+ gdbpy_enter enter_py (python_gdbarch, python_language);
+
+ if (evregpy_no_listeners_p (gdb_py_events.inferior_deleted))
+ return;
+
+ gdbpy_ref<> inf_obj (inferior_to_inferior_object (inf));
+ if (inf_obj == NULL)
+ {
+ gdbpy_print_stack ();
+ return;
+ }
+
+ gdbpy_ref<> event (create_event_object (&inferior_deleted_event_object_type));
+ if (event == NULL
+ || evpy_add_attribute (event.get (), "inferior", inf_obj.get ()) < 0
+ || evpy_emit_event (event.get (), gdb_py_events.inferior_deleted) < 0)
+ gdbpy_print_stack ();
+}
+
/* Finds the Python Inferior object for the given PID. Returns a
reference, or NULL if PID does not match any inferior object. */

@@ -298,6 +359,15 @@ add_thread_object (struct thread_info *tp)

inf_obj->threads = entry;
inf_obj->nthreads++;
+
+ if (evregpy_no_listeners_p (gdb_py_events.new_thread))
+ return;
+
+ gdbpy_ref<> event (create_thread_event_object (&new_thread_event_object_type,
+ (PyObject *) thread_obj));
+ if (event == NULL
+ || evpy_emit_event (event.get (), gdb_py_events.new_thread) < 0)
+ gdbpy_print_stack ();
}

static void
@@ -823,6 +893,8 @@ gdbpy_initialize_inferior (void)
observer_attach_register_changed (python_on_register_change);
observer_attach_inferior_exit (python_inferior_exit);
observer_attach_new_objfile (python_new_objfile);
+ observer_attach_inferior_added (python_new_inferior);
+ observer_attach_inferior_removed (python_inferior_deleted);

membuf_object_type.tp_new = PyType_GenericNew;
if (PyType_Ready (&membuf_object_type) < 0)
@@ -970,3 +1042,19 @@ PyTypeObject membuf_object_type = {
0, /* tp_init */
0, /* tp_alloc */
};
+
+GDBPY_NEW_EVENT_TYPE (new_thread,
+ "gdb.NewThreadEvent",
+ "NewThreadEvent",
+ "GDB new thread event object",
+ thread_event_object_type);
+GDBPY_NEW_EVENT_TYPE (new_inferior,
+ "gdb.NewInferiorEvent",
+ "NewInferiorEvent",
+ "GDB new inferior event object",
+ event_object_type);
+GDBPY_NEW_EVENT_TYPE (inferior_deleted,
+ "gdb.InferiorDeletedEvent",
+ "InferiorDeletedEvent",
+ "GDB inferior deleted event object",
+ event_object_type);
diff --git a/gdb/python/py-threadevent.c b/gdb/python/py-threadevent.c
index 9217444..7211fa2 100644
--- a/gdb/python/py-threadevent.c
+++ b/gdb/python/py-threadevent.c
@@ -48,17 +48,18 @@ get_event_thread (void)
}

PyObject *
-create_thread_event_object (PyTypeObject *py_type)
+create_thread_event_object (PyTypeObject *py_type, PyObject *thread)
{
- PyObject *thread = NULL;
-
gdbpy_ref<> thread_event_obj (create_event_object (py_type));
if (thread_event_obj == NULL)
return NULL;

- thread = get_event_thread ();
- if (!thread)
- return NULL;
+ if (thread == NULL)
+ {
+ thread = get_event_thread ();
+ if (!thread)
+ return NULL;
+ }

if (evpy_add_attribute (thread_event_obj.get (),
"inferior_thread",
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index ebb83f0..0c3582f 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -630,6 +630,12 @@ int gdbpy_initialize_new_objfile_event (void)
CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
int gdbpy_initialize_clear_objfiles_event (void)
CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
+int gdbpy_initialize_new_inferior_event (void)
+ CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
+int gdbpy_initialize_inferior_deleted_event (void)
+ CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
+int gdbpy_initialize_new_thread_event (void)
+ CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
int gdbpy_initialize_arch (void)
CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION;
int gdbpy_initialize_xmethods (void)
diff --git a/gdb/python/python.c b/gdb/python/python.c
index f40fe89..7ff84e4 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -1609,6 +1609,9 @@ do_start_initialization ()
|| gdbpy_initialize_thread_event () < 0
|| gdbpy_initialize_new_objfile_event () < 0
|| gdbpy_initialize_clear_objfiles_event () < 0
+ || gdbpy_initialize_new_inferior_event () < 0
+ || gdbpy_initialize_inferior_deleted_event () < 0
+ || gdbpy_initialize_new_thread_event () < 0
|| gdbpy_initialize_arch () < 0
|| gdbpy_initialize_xmethods () < 0
|| gdbpy_initialize_unwind () < 0)
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 8d8dc3c..e982684 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-09-08 Tom Tromey <tom@tromey.com>
+
+ * gdb.python/py-infthread.exp: Add tests for new_thread event.
+ * gdb.python/py-inferior.exp: Add tests for new inferior events.
+
2017-09-08 Christoph Weinmann <christoph.t.weinmann@intel.com>

* gdb.fortran/printing-types.exp: New file.
diff --git a/gdb/testsuite/gdb.python/py-inferior.exp b/gdb/testsuite/gdb.python/py-inferior.exp
index c2ea2c2..715c693 100644
--- a/gdb/testsuite/gdb.python/py-inferior.exp
+++ b/gdb/testsuite/gdb.python/py-inferior.exp
@@ -214,12 +214,33 @@ with_test_prefix "is_valid" {
gdb_test "python print (inf_list\[0\].is_valid())" "True" \
"check inferior validity 1"

+ gdb_py_test_multiple "install new inferior event handler" \
+ "python" "" \
+ "my_inferior_count = 1" "" \
+ "def new_inf_handler(evt):" "" \
+ " global my_inferior_count" "" \
+ " if evt.inferior is not None:" "" \
+ " my_inferior_count = my_inferior_count + 1" "" \
+ "gdb.events.new_inferior.connect(new_inf_handler)" "" \
+ "end" ""
+ gdb_py_test_multiple "install inferior deleted event handler" \
+ "python" "" \
+ "def del_inf_handler(evt):" "" \
+ " global my_inferior_count" "" \
+ " if evt.inferior is not None:" "" \
+ " my_inferior_count = my_inferior_count - 1" "" \
+ "gdb.events.inferior_deleted.connect(del_inf_handler)" "" \
+ "end" ""
+
gdb_test "add-inferior" "Added inferior 2.*" "add empty inferior 2"
gdb_py_test_silent_cmd "python inf_list = gdb.inferiors()" "get new list" 1
gdb_test "python print (len(inf_list))" "2" "get inferior list length 2"
gdb_test "python print (inf_list\[0\].is_valid())" "True" \
"check inferior validity 2"

+ gdb_test "python print (my_inferior_count)" "2" \
+ "test new-inferior event handler"
+
gdb_test "python print (inf_list\[1\].is_valid())" "True" \
"check inferior validity 3"

@@ -229,6 +250,9 @@ with_test_prefix "is_valid" {

gdb_test "python print (inf_list\[1\].is_valid())" "False" \
"check inferior validity 5"
+
+ gdb_test "python print (my_inferior_count)" "1" \
+ "test inferior-deleted event handler"
}

# Test gdb.selected_inferior()
diff --git a/gdb/testsuite/gdb.python/py-infthread.exp b/gdb/testsuite/gdb.python/py-infthread.exp
index a5fed8d..0711d69 100644
--- a/gdb/testsuite/gdb.python/py-infthread.exp
+++ b/gdb/testsuite/gdb.python/py-infthread.exp
@@ -30,6 +30,16 @@ clean_restart ${testfile}
# Skip all tests if Python scripting is not enabled.
if { [skip_python_tests] } { continue }

+gdb_py_test_multiple "install new_thread event handler" \
+ "python" "" \
+ "seen_a_thread = False" "" \
+ "def thread_handler(evt):" "" \
+ " if evt.inferior_thread is not None:" "" \
+ " global seen_a_thread" "" \
+ " seen_a_thread = True" "" \
+ "gdb.events.new_thread.connect(thread_handler)" "" \
+ "end" ""
+
# The following tests require execution.

if ![runto_main] then {
@@ -37,6 +47,8 @@ if ![runto_main] then {
return 0
}

+gdb_test "python print(seen_a_thread)" "True"
+
# Test basic gdb.Inferior attributes and methods.

gdb_py_test_silent_cmd "python t0 = gdb.selected_thread ()" "test gdb.selected_thread" 1
--
2.9.4