1 /* Python interface to finish breakpoints
3 Copyright (C) 2011-2019 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
;
43 /* gdb.Type object of the value return by the breakpointed function.
44 May be NULL if no debug information was available or return type
46 PyObject
*return_type
;
47 /* gdb.Value object of the function finished by this breakpoint. Will be
48 NULL if return_type is NULL. */
49 PyObject
*function_value
;
50 /* When stopped at this FinishBreakpoint, gdb.Value object returned by
51 the function; Py_None if the value is not computable; NULL if GDB is
52 not stopped at a FinishBreakpoint. */
53 PyObject
*return_value
;
56 extern PyTypeObject finish_breakpoint_object_type
57 CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("finish_breakpoint_object");
59 /* Python function to get the 'return_value' attribute of
63 bpfinishpy_get_returnvalue (PyObject
*self
, void *closure
)
65 struct finish_breakpoint_object
*self_finishbp
=
66 (struct finish_breakpoint_object
*) self
;
68 if (!self_finishbp
->return_value
)
71 Py_INCREF (self_finishbp
->return_value
);
72 return self_finishbp
->return_value
;
75 /* Deallocate FinishBreakpoint object. */
78 bpfinishpy_dealloc (PyObject
*self
)
80 struct finish_breakpoint_object
*self_bpfinish
=
81 (struct finish_breakpoint_object
*) self
;
83 Py_XDECREF (self_bpfinish
->function_value
);
84 Py_XDECREF (self_bpfinish
->return_type
);
85 Py_XDECREF (self_bpfinish
->return_value
);
88 /* Triggered when gdbpy_should_stop is about to execute the `stop' callback
89 of the gdb.FinishBreakpoint object BP_OBJ. Will compute and cache the
90 `return_value', if possible. */
93 bpfinishpy_pre_stop_hook (struct gdbpy_breakpoint_object
*bp_obj
)
95 struct finish_breakpoint_object
*self_finishbp
=
96 (struct finish_breakpoint_object
*) bp_obj
;
98 /* Can compute return_value only once. */
99 gdb_assert (!self_finishbp
->return_value
);
101 if (!self_finishbp
->return_type
)
106 struct value
*function
=
107 value_object_to_value (self_finishbp
->function_value
);
108 struct type
*value_type
=
109 type_object_to_type (self_finishbp
->return_type
);
110 struct value
*ret
= get_return_value (function
, value_type
);
114 self_finishbp
->return_value
= value_to_value_object (ret
);
115 if (!self_finishbp
->return_value
)
116 gdbpy_print_stack ();
121 self_finishbp
->return_value
= Py_None
;
124 catch (const gdb_exception
&except
)
126 gdbpy_convert_exception (except
);
127 gdbpy_print_stack ();
131 /* Triggered when gdbpy_should_stop has triggered the `stop' callback
132 of the gdb.FinishBreakpoint object BP_OBJ. */
135 bpfinishpy_post_stop_hook (struct gdbpy_breakpoint_object
*bp_obj
)
140 /* Can't delete it here, but it will be removed at the next stop. */
141 disable_breakpoint (bp_obj
->bp
);
142 gdb_assert (bp_obj
->bp
->disposition
== disp_del
);
144 catch (const gdb_exception
&except
)
146 gdbpy_convert_exception (except
);
147 gdbpy_print_stack ();
151 /* Python function to create a new breakpoint. */
154 bpfinishpy_init (PyObject
*self
, PyObject
*args
, PyObject
*kwargs
)
156 static const char *keywords
[] = { "frame", "internal", NULL
};
157 struct finish_breakpoint_object
*self_bpfinish
=
158 (struct finish_breakpoint_object
*) self
;
159 PyObject
*frame_obj
= NULL
;
161 struct frame_info
*frame
= NULL
; /* init for gcc -Wall */
162 struct frame_info
*prev_frame
= NULL
;
163 struct frame_id frame_id
;
164 PyObject
*internal
= NULL
;
167 struct symbol
*function
;
169 if (!gdb_PyArg_ParseTupleAndKeywords (args
, kwargs
, "|OO", keywords
,
170 &frame_obj
, &internal
))
175 /* Default frame to newest frame if necessary. */
176 if (frame_obj
== NULL
)
177 frame
= get_current_frame ();
179 frame
= frame_object_to_frame_info (frame_obj
);
183 PyErr_SetString (PyExc_ValueError
,
184 _("Invalid ID for the `frame' object."));
188 prev_frame
= get_prev_frame (frame
);
191 PyErr_SetString (PyExc_ValueError
,
192 _("\"FinishBreakpoint\" not "
193 "meaningful in the outermost "
196 else if (get_frame_type (prev_frame
) == DUMMY_FRAME
)
198 PyErr_SetString (PyExc_ValueError
,
199 _("\"FinishBreakpoint\" cannot "
200 "be set on a dummy frame."));
204 frame_id
= get_frame_id (prev_frame
);
205 if (frame_id_eq (frame_id
, null_frame_id
))
206 PyErr_SetString (PyExc_ValueError
,
207 _("Invalid ID for the `frame' object."));
211 catch (const gdb_exception
&except
)
213 gdbpy_convert_exception (except
);
217 if (PyErr_Occurred ())
220 if (inferior_ptid
== null_ptid
)
222 PyErr_SetString (PyExc_ValueError
,
223 _("No thread currently selected."));
227 thread
= inferior_thread ()->global_num
;
231 internal_bp
= PyObject_IsTrue (internal
);
232 if (internal_bp
== -1)
234 PyErr_SetString (PyExc_ValueError
,
235 _("The value of `internal' must be a boolean."));
240 /* Find the function we will return from. */
241 self_bpfinish
->return_type
= NULL
;
242 self_bpfinish
->function_value
= NULL
;
246 if (get_frame_pc_if_available (frame
, &pc
))
248 function
= find_pc_function (pc
);
249 if (function
!= NULL
)
251 struct type
*ret_type
=
252 check_typedef (TYPE_TARGET_TYPE (SYMBOL_TYPE (function
)));
254 /* Remember only non-void return types. */
255 if (TYPE_CODE (ret_type
) != TYPE_CODE_VOID
)
257 struct value
*func_value
;
259 /* Ignore Python errors at this stage. */
260 self_bpfinish
->return_type
= type_to_type_object (ret_type
);
262 func_value
= read_var_value (function
, NULL
, frame
);
263 self_bpfinish
->function_value
=
264 value_to_value_object (func_value
);
270 catch (const gdb_exception
&except
)
272 /* Just swallow. Either the return type or the function value
276 if (self_bpfinish
->return_type
== NULL
|| self_bpfinish
->function_value
== NULL
)
278 /* Won't be able to compute return value. */
279 Py_XDECREF (self_bpfinish
->return_type
);
280 Py_XDECREF (self_bpfinish
->function_value
);
282 self_bpfinish
->return_type
= NULL
;
283 self_bpfinish
->function_value
= NULL
;
286 bppy_pending_object
= &self_bpfinish
->py_bp
;
287 bppy_pending_object
->number
= -1;
288 bppy_pending_object
->bp
= NULL
;
292 /* Set a breakpoint on the return address. */
293 event_location_up location
294 = new_address_location (get_frame_pc (prev_frame
), NULL
, 0);
295 create_breakpoint (python_gdbarch
,
296 location
.get (), NULL
, thread
, NULL
,
302 &bkpt_breakpoint_ops
,
303 0, 1, internal_bp
, 0);
305 catch (const gdb_exception
&except
)
307 GDB_PY_SET_HANDLE_EXCEPTION (except
);
310 self_bpfinish
->py_bp
.bp
->frame_id
= frame_id
;
311 self_bpfinish
->py_bp
.is_finish_bp
= 1;
313 /* Bind the breakpoint with the current program space. */
314 self_bpfinish
->py_bp
.bp
->pspace
= current_program_space
;
319 /* Called when GDB notices that the finish breakpoint BP_OBJ is out of
320 the current callstack. Triggers the method OUT_OF_SCOPE if implemented,
321 then delete the breakpoint. */
324 bpfinishpy_out_of_scope (struct finish_breakpoint_object
*bpfinish_obj
)
326 gdbpy_breakpoint_object
*bp_obj
= (gdbpy_breakpoint_object
*) bpfinish_obj
;
327 PyObject
*py_obj
= (PyObject
*) bp_obj
;
329 if (bpfinish_obj
->py_bp
.bp
->enable_state
== bp_enabled
330 && PyObject_HasAttrString (py_obj
, outofscope_func
))
332 gdbpy_ref
<> meth_result (PyObject_CallMethod (py_obj
, outofscope_func
,
334 if (meth_result
== NULL
)
335 gdbpy_print_stack ();
338 delete_breakpoint (bpfinish_obj
->py_bp
.bp
);
341 /* Callback for `bpfinishpy_detect_out_scope'. Triggers Python's
342 `B->out_of_scope' function if B is a FinishBreakpoint out of its scope. */
345 bpfinishpy_detect_out_scope_cb (struct breakpoint
*b
, void *args
)
347 struct breakpoint
*bp_stopped
= (struct breakpoint
*) args
;
348 PyObject
*py_bp
= (PyObject
*) b
->py_bp_object
;
350 /* Trigger out_of_scope if this is a FinishBreakpoint and its frame is
351 not anymore in the current callstack. */
352 if (py_bp
!= NULL
&& b
->py_bp_object
->is_finish_bp
)
354 struct finish_breakpoint_object
*finish_bp
=
355 (struct finish_breakpoint_object
*) py_bp
;
357 /* Check scope if not currently stopped at the FinishBreakpoint. */
362 if (b
->pspace
== current_inferior ()->pspace
363 && (!target_has_registers
364 || frame_find_by_id (b
->frame_id
) == NULL
))
365 bpfinishpy_out_of_scope (finish_bp
);
367 catch (const gdb_exception
&except
)
369 gdbpy_convert_exception (except
);
370 gdbpy_print_stack ();
378 /* Attached to `stop' notifications, check if the execution has run
379 out of the scope of any FinishBreakpoint before it has been hit. */
382 bpfinishpy_handle_stop (struct bpstats
*bs
, int print_frame
)
384 gdbpy_enter
enter_py (get_current_arch (), current_language
);
386 iterate_over_breakpoints (bpfinishpy_detect_out_scope_cb
,
387 bs
== NULL
? NULL
: bs
->breakpoint_at
);
390 /* Attached to `exit' notifications, triggers all the necessary out of
391 scope notifications. */
394 bpfinishpy_handle_exit (struct inferior
*inf
)
396 gdbpy_enter
enter_py (target_gdbarch (), current_language
);
398 iterate_over_breakpoints (bpfinishpy_detect_out_scope_cb
, NULL
);
401 /* Initialize the Python finish breakpoint code. */
404 gdbpy_initialize_finishbreakpoints (void)
406 if (PyType_Ready (&finish_breakpoint_object_type
) < 0)
409 if (gdb_pymodule_addobject (gdb_module
, "FinishBreakpoint",
410 (PyObject
*) &finish_breakpoint_object_type
) < 0)
413 gdb::observers::normal_stop
.attach (bpfinishpy_handle_stop
);
414 gdb::observers::inferior_exit
.attach (bpfinishpy_handle_exit
);
419 static gdb_PyGetSetDef finish_breakpoint_object_getset
[] = {
420 { "return_value", bpfinishpy_get_returnvalue
, NULL
,
421 "gdb.Value object representing the return value, if any. \
422 None otherwise.", NULL
},
423 { NULL
} /* Sentinel. */
426 PyTypeObject finish_breakpoint_object_type
=
428 PyVarObject_HEAD_INIT (NULL
, 0)
429 "gdb.FinishBreakpoint", /*tp_name*/
430 sizeof (struct finish_breakpoint_object
), /*tp_basicsize*/
432 bpfinishpy_dealloc
, /*tp_dealloc*/
439 0, /*tp_as_sequence*/
447 Py_TPFLAGS_DEFAULT
| Py_TPFLAGS_BASETYPE
, /*tp_flags*/
448 "GDB finish breakpoint object", /* tp_doc */
451 0, /* tp_richcompare */
452 0, /* tp_weaklistoffset */
457 finish_breakpoint_object_getset
,/* tp_getset */
458 &breakpoint_object_type
, /* tp_base */
460 0, /* tp_descr_get */
461 0, /* tp_descr_set */
462 0, /* tp_dictoffset */
463 bpfinishpy_init
, /* tp_init */