1 /* Python interface to finish breakpoints
3 Copyright (C) 2011-2022 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "python-internal.h"
24 #include "breakpoint.h"
26 #include "gdbthread.h"
27 #include "arch-utils.h"
29 #include "observable.h"
34 /* Function that is called when a Python finish bp is found out of scope. */
35 static const char outofscope_func
[] = "out_of_scope";
37 /* struct implementing the gdb.FinishBreakpoint object by extending
38 the gdb.Breakpoint class. */
39 struct finish_breakpoint_object
41 /* gdb.Breakpoint base class. */
42 gdbpy_breakpoint_object py_bp
;
44 /* gdb.Symbol object of the function finished by this breakpoint.
46 nullptr if no debug information was available or return type was VOID. */
47 PyObject
*func_symbol
;
49 /* gdb.Value object of the function finished by this breakpoint.
51 nullptr if no debug information was available or return type was VOID. */
52 PyObject
*function_value
;
54 /* When stopped at this FinishBreakpoint, gdb.Value object returned by
55 the function; Py_None if the value is not computable; NULL if GDB is
56 not stopped at a FinishBreakpoint. */
57 PyObject
*return_value
;
60 extern PyTypeObject finish_breakpoint_object_type
61 CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("finish_breakpoint_object");
63 /* Python function to get the 'return_value' attribute of
67 bpfinishpy_get_returnvalue (PyObject
*self
, void *closure
)
69 struct finish_breakpoint_object
*self_finishbp
=
70 (struct finish_breakpoint_object
*) self
;
72 if (!self_finishbp
->return_value
)
75 Py_INCREF (self_finishbp
->return_value
);
76 return self_finishbp
->return_value
;
79 /* Deallocate FinishBreakpoint object. */
82 bpfinishpy_dealloc (PyObject
*self
)
84 struct finish_breakpoint_object
*self_bpfinish
=
85 (struct finish_breakpoint_object
*) self
;
87 Py_XDECREF (self_bpfinish
->func_symbol
);
88 Py_XDECREF (self_bpfinish
->function_value
);
89 Py_XDECREF (self_bpfinish
->return_value
);
90 Py_TYPE (self
)->tp_free (self
);
93 /* Triggered when gdbpy_should_stop is about to execute the `stop' callback
94 of the gdb.FinishBreakpoint object BP_OBJ. Will compute and cache the
95 `return_value', if possible. */
98 bpfinishpy_pre_stop_hook (struct gdbpy_breakpoint_object
*bp_obj
)
100 struct finish_breakpoint_object
*self_finishbp
=
101 (struct finish_breakpoint_object
*) bp_obj
;
103 /* Can compute return_value only once. */
104 gdb_assert (!self_finishbp
->return_value
);
106 if (self_finishbp
->func_symbol
== nullptr)
111 struct symbol
*func_symbol
=
112 symbol_object_to_symbol (self_finishbp
->func_symbol
);
113 struct value
*function
=
114 value_object_to_value (self_finishbp
->function_value
);
116 get_return_value (func_symbol
, function
);
120 self_finishbp
->return_value
= value_to_value_object (ret
);
121 if (!self_finishbp
->return_value
)
122 gdbpy_print_stack ();
127 self_finishbp
->return_value
= Py_None
;
130 catch (const gdb_exception
&except
)
132 gdbpy_convert_exception (except
);
133 gdbpy_print_stack ();
137 /* Triggered when gdbpy_should_stop has triggered the `stop' callback
138 of the gdb.FinishBreakpoint object BP_OBJ. */
141 bpfinishpy_post_stop_hook (struct gdbpy_breakpoint_object
*bp_obj
)
146 /* Can't delete it here, but it will be removed at the next stop. */
147 disable_breakpoint (bp_obj
->bp
);
148 gdb_assert (bp_obj
->bp
->disposition
== disp_del
);
150 catch (const gdb_exception
&except
)
152 gdbpy_convert_exception (except
);
153 gdbpy_print_stack ();
157 /* Python function to create a new breakpoint. */
160 bpfinishpy_init (PyObject
*self
, PyObject
*args
, PyObject
*kwargs
)
162 static const char *keywords
[] = { "frame", "internal", NULL
};
163 struct finish_breakpoint_object
*self_bpfinish
=
164 (struct finish_breakpoint_object
*) self
;
165 PyObject
*frame_obj
= NULL
;
167 struct frame_info
*frame
= NULL
; /* init for gcc -Wall */
168 struct frame_info
*prev_frame
= NULL
;
169 struct frame_id frame_id
;
170 PyObject
*internal
= NULL
;
174 if (!gdb_PyArg_ParseTupleAndKeywords (args
, kwargs
, "|OO", keywords
,
175 &frame_obj
, &internal
))
180 /* Default frame to newest frame if necessary. */
181 if (frame_obj
== NULL
)
182 frame
= get_current_frame ();
184 frame
= frame_object_to_frame_info (frame_obj
);
188 PyErr_SetString (PyExc_ValueError
,
189 _("Invalid ID for the `frame' object."));
193 prev_frame
= get_prev_frame (frame
);
196 PyErr_SetString (PyExc_ValueError
,
197 _("\"FinishBreakpoint\" not "
198 "meaningful in the outermost "
201 else if (get_frame_type (prev_frame
) == DUMMY_FRAME
)
203 PyErr_SetString (PyExc_ValueError
,
204 _("\"FinishBreakpoint\" cannot "
205 "be set on a dummy frame."));
209 frame_id
= get_frame_id (prev_frame
);
210 if (frame_id_eq (frame_id
, null_frame_id
))
211 PyErr_SetString (PyExc_ValueError
,
212 _("Invalid ID for the `frame' object."));
216 catch (const gdb_exception
&except
)
218 gdbpy_convert_exception (except
);
222 if (PyErr_Occurred ())
225 if (inferior_ptid
== null_ptid
)
227 PyErr_SetString (PyExc_ValueError
,
228 _("No thread currently selected."));
232 thread
= inferior_thread ()->global_num
;
236 internal_bp
= PyObject_IsTrue (internal
);
237 if (internal_bp
== -1)
239 PyErr_SetString (PyExc_ValueError
,
240 _("The value of `internal' must be a boolean."));
245 /* Find the function we will return from. */
246 self_bpfinish
->func_symbol
= nullptr;
247 self_bpfinish
->function_value
= nullptr;
251 if (get_frame_pc_if_available (frame
, &pc
))
253 struct symbol
*function
= find_pc_function (pc
);
254 if (function
!= nullptr)
256 struct type
*ret_type
=
257 check_typedef (TYPE_TARGET_TYPE (function
->type ()));
259 /* Remember only non-void return types. */
260 if (ret_type
->code () != TYPE_CODE_VOID
)
262 /* Ignore Python errors at this stage. */
263 value
*func_value
= read_var_value (function
, NULL
, frame
);
264 self_bpfinish
->function_value
265 = value_to_value_object (func_value
);
268 self_bpfinish
->func_symbol
269 = symbol_to_symbol_object (function
);
275 catch (const gdb_exception
&except
)
277 /* Just swallow. Either the return type or the function value
281 if (self_bpfinish
->func_symbol
== nullptr
282 || self_bpfinish
->function_value
== nullptr)
284 /* Won't be able to compute return value. */
285 Py_XDECREF (self_bpfinish
->func_symbol
);
286 Py_XDECREF (self_bpfinish
->function_value
);
288 self_bpfinish
->func_symbol
= nullptr;
289 self_bpfinish
->function_value
= nullptr;
292 bppy_pending_object
= &self_bpfinish
->py_bp
;
293 bppy_pending_object
->number
= -1;
294 bppy_pending_object
->bp
= NULL
;
298 /* Set a breakpoint on the return address. */
299 event_location_up location
300 = new_address_location (get_frame_pc (prev_frame
), NULL
, 0);
301 create_breakpoint (gdbpy_enter::get_gdbarch (),
302 location
.get (), NULL
, thread
, NULL
, false,
308 &code_breakpoint_ops
,
309 0, 1, internal_bp
, 0);
311 catch (const gdb_exception
&except
)
313 GDB_PY_SET_HANDLE_EXCEPTION (except
);
316 self_bpfinish
->py_bp
.bp
->frame_id
= frame_id
;
317 self_bpfinish
->py_bp
.is_finish_bp
= 1;
319 /* Bind the breakpoint with the current program space. */
320 self_bpfinish
->py_bp
.bp
->pspace
= current_program_space
;
325 /* Called when GDB notices that the finish breakpoint BP_OBJ is out of
326 the current callstack. Triggers the method OUT_OF_SCOPE if implemented,
327 then delete the breakpoint. */
330 bpfinishpy_out_of_scope (struct finish_breakpoint_object
*bpfinish_obj
)
332 gdbpy_breakpoint_object
*bp_obj
= (gdbpy_breakpoint_object
*) bpfinish_obj
;
333 PyObject
*py_obj
= (PyObject
*) bp_obj
;
335 if (bpfinish_obj
->py_bp
.bp
->enable_state
== bp_enabled
336 && PyObject_HasAttrString (py_obj
, outofscope_func
))
338 gdbpy_ref
<> meth_result (PyObject_CallMethod (py_obj
, outofscope_func
,
340 if (meth_result
== NULL
)
341 gdbpy_print_stack ();
344 delete_breakpoint (bpfinish_obj
->py_bp
.bp
);
347 /* Callback for `bpfinishpy_detect_out_scope'. Triggers Python's
348 `B->out_of_scope' function if B is a FinishBreakpoint out of its scope. */
351 bpfinishpy_detect_out_scope_cb (struct breakpoint
*b
,
352 struct breakpoint
*bp_stopped
)
354 PyObject
*py_bp
= (PyObject
*) b
->py_bp_object
;
356 /* Trigger out_of_scope if this is a FinishBreakpoint and its frame is
357 not anymore in the current callstack. */
358 if (py_bp
!= NULL
&& b
->py_bp_object
->is_finish_bp
)
360 struct finish_breakpoint_object
*finish_bp
=
361 (struct finish_breakpoint_object
*) py_bp
;
363 /* Check scope if not currently stopped at the FinishBreakpoint. */
368 if (b
->pspace
== current_inferior ()->pspace
369 && (!target_has_registers ()
370 || frame_find_by_id (b
->frame_id
) == NULL
))
371 bpfinishpy_out_of_scope (finish_bp
);
373 catch (const gdb_exception
&except
)
375 gdbpy_convert_exception (except
);
376 gdbpy_print_stack ();
382 /* Attached to `stop' notifications, check if the execution has run
383 out of the scope of any FinishBreakpoint before it has been hit. */
386 bpfinishpy_handle_stop (struct bpstat
*bs
, int print_frame
)
388 gdbpy_enter enter_py
;
390 for (breakpoint
*bp
: all_breakpoints_safe ())
391 bpfinishpy_detect_out_scope_cb (bp
, bs
== NULL
? NULL
: bs
->breakpoint_at
);
394 /* Attached to `exit' notifications, triggers all the necessary out of
395 scope notifications. */
398 bpfinishpy_handle_exit (struct inferior
*inf
)
400 gdbpy_enter
enter_py (target_gdbarch ());
402 for (breakpoint
*bp
: all_breakpoints_safe ())
403 bpfinishpy_detect_out_scope_cb (bp
, nullptr);
406 /* Initialize the Python finish breakpoint code. */
409 gdbpy_initialize_finishbreakpoints (void)
411 if (PyType_Ready (&finish_breakpoint_object_type
) < 0)
414 if (gdb_pymodule_addobject (gdb_module
, "FinishBreakpoint",
415 (PyObject
*) &finish_breakpoint_object_type
) < 0)
418 gdb::observers::normal_stop
.attach (bpfinishpy_handle_stop
,
419 "py-finishbreakpoint");
420 gdb::observers::inferior_exit
.attach (bpfinishpy_handle_exit
,
421 "py-finishbreakpoint");
426 static gdb_PyGetSetDef finish_breakpoint_object_getset
[] = {
427 { "return_value", bpfinishpy_get_returnvalue
, NULL
,
428 "gdb.Value object representing the return value, if any. \
429 None otherwise.", NULL
},
430 { NULL
} /* Sentinel. */
433 PyTypeObject finish_breakpoint_object_type
=
435 PyVarObject_HEAD_INIT (NULL
, 0)
436 "gdb.FinishBreakpoint", /*tp_name*/
437 sizeof (struct finish_breakpoint_object
), /*tp_basicsize*/
439 bpfinishpy_dealloc
, /*tp_dealloc*/
446 0, /*tp_as_sequence*/
454 Py_TPFLAGS_DEFAULT
| Py_TPFLAGS_BASETYPE
, /*tp_flags*/
455 "GDB finish breakpoint object", /* tp_doc */
458 0, /* tp_richcompare */
459 0, /* tp_weaklistoffset */
464 finish_breakpoint_object_getset
,/* tp_getset */
465 &breakpoint_object_type
, /* tp_base */
467 0, /* tp_descr_get */
468 0, /* tp_descr_set */
469 0, /* tp_dictoffset */
470 bpfinishpy_init
, /* tp_init */