1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
|
/* Python interface to finish breakpoints
Copyright (C) 2011-2022 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 "python-internal.h"
#include "breakpoint.h"
#include "frame.h"
#include "gdbthread.h"
#include "arch-utils.h"
#include "language.h"
#include "observable.h"
#include "inferior.h"
#include "block.h"
#include "location.h"
/* Function that is called when a Python finish bp is found out of scope. */
static const char outofscope_func[] = "out_of_scope";
/* struct implementing the gdb.FinishBreakpoint object by extending
the gdb.Breakpoint class. */
struct finish_breakpoint_object
{
/* gdb.Breakpoint base class. */
gdbpy_breakpoint_object py_bp;
/* gdb.Symbol object of the function finished by this breakpoint.
nullptr if no debug information was available or return type was VOID. */
PyObject *func_symbol;
/* gdb.Value object of the function finished by this breakpoint.
nullptr if no debug information was available or return type was VOID. */
PyObject *function_value;
/* When stopped at this FinishBreakpoint, gdb.Value object returned by
the function; Py_None if the value is not computable; NULL if GDB is
not stopped at a FinishBreakpoint. */
PyObject *return_value;
};
extern PyTypeObject finish_breakpoint_object_type
CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("finish_breakpoint_object");
/* Python function to get the 'return_value' attribute of
FinishBreakpoint. */
static PyObject *
bpfinishpy_get_returnvalue (PyObject *self, void *closure)
{
struct finish_breakpoint_object *self_finishbp =
(struct finish_breakpoint_object *) self;
if (!self_finishbp->return_value)
Py_RETURN_NONE;
Py_INCREF (self_finishbp->return_value);
return self_finishbp->return_value;
}
/* Deallocate FinishBreakpoint object. */
static void
bpfinishpy_dealloc (PyObject *self)
{
struct finish_breakpoint_object *self_bpfinish =
(struct finish_breakpoint_object *) self;
Py_XDECREF (self_bpfinish->func_symbol);
Py_XDECREF (self_bpfinish->function_value);
Py_XDECREF (self_bpfinish->return_value);
Py_TYPE (self)->tp_free (self);
}
/* Triggered when gdbpy_should_stop is about to execute the `stop' callback
of the gdb.FinishBreakpoint object BP_OBJ. Will compute and cache the
`return_value', if possible. */
void
bpfinishpy_pre_stop_hook (struct gdbpy_breakpoint_object *bp_obj)
{
struct finish_breakpoint_object *self_finishbp =
(struct finish_breakpoint_object *) bp_obj;
/* Can compute return_value only once. */
gdb_assert (!self_finishbp->return_value);
if (self_finishbp->func_symbol == nullptr)
return;
try
{
struct symbol *func_symbol =
symbol_object_to_symbol (self_finishbp->func_symbol);
struct value *function =
value_object_to_value (self_finishbp->function_value);
struct value *ret =
get_return_value (func_symbol, function);
if (ret)
{
self_finishbp->return_value = value_to_value_object (ret);
if (!self_finishbp->return_value)
gdbpy_print_stack ();
}
else
{
Py_INCREF (Py_None);
self_finishbp->return_value = Py_None;
}
}
catch (const gdb_exception &except)
{
gdbpy_convert_exception (except);
gdbpy_print_stack ();
}
}
/* Triggered when gdbpy_should_stop has triggered the `stop' callback
of the gdb.FinishBreakpoint object BP_OBJ. */
void
bpfinishpy_post_stop_hook (struct gdbpy_breakpoint_object *bp_obj)
{
try
{
/* Can't delete it here, but it will be removed at the next stop. */
disable_breakpoint (bp_obj->bp);
gdb_assert (bp_obj->bp->disposition == disp_del);
}
catch (const gdb_exception &except)
{
gdbpy_convert_exception (except);
gdbpy_print_stack ();
}
}
/* Python function to create a new breakpoint. */
static int
bpfinishpy_init (PyObject *self, PyObject *args, PyObject *kwargs)
{
static const char *keywords[] = { "frame", "internal", NULL };
struct finish_breakpoint_object *self_bpfinish =
(struct finish_breakpoint_object *) self;
PyObject *frame_obj = NULL;
int thread;
struct frame_info *frame = NULL; /* init for gcc -Wall */
struct frame_info *prev_frame = NULL;
struct frame_id frame_id;
PyObject *internal = NULL;
int internal_bp = 0;
CORE_ADDR pc;
if (!gdb_PyArg_ParseTupleAndKeywords (args, kwargs, "|OO", keywords,
&frame_obj, &internal))
return -1;
try
{
/* Default frame to newest frame if necessary. */
if (frame_obj == NULL)
frame = get_current_frame ();
else
frame = frame_object_to_frame_info (frame_obj);
if (frame == NULL)
{
PyErr_SetString (PyExc_ValueError,
_("Invalid ID for the `frame' object."));
}
else
{
prev_frame = get_prev_frame (frame);
if (prev_frame == 0)
{
PyErr_SetString (PyExc_ValueError,
_("\"FinishBreakpoint\" not "
"meaningful in the outermost "
"frame."));
}
else if (get_frame_type (prev_frame) == DUMMY_FRAME)
{
PyErr_SetString (PyExc_ValueError,
_("\"FinishBreakpoint\" cannot "
"be set on a dummy frame."));
}
else
{
frame_id = get_frame_id (prev_frame);
if (frame_id_eq (frame_id, null_frame_id))
PyErr_SetString (PyExc_ValueError,
_("Invalid ID for the `frame' object."));
}
}
}
catch (const gdb_exception &except)
{
gdbpy_convert_exception (except);
return -1;
}
if (PyErr_Occurred ())
return -1;
if (inferior_ptid == null_ptid)
{
PyErr_SetString (PyExc_ValueError,
_("No thread currently selected."));
return -1;
}
thread = inferior_thread ()->global_num;
if (internal)
{
internal_bp = PyObject_IsTrue (internal);
if (internal_bp == -1)
{
PyErr_SetString (PyExc_ValueError,
_("The value of `internal' must be a boolean."));
return -1;
}
}
/* Find the function we will return from. */
self_bpfinish->func_symbol = nullptr;
self_bpfinish->function_value = nullptr;
try
{
if (get_frame_pc_if_available (frame, &pc))
{
struct symbol *function = find_pc_function (pc);
if (function != nullptr)
{
struct type *ret_type =
check_typedef (TYPE_TARGET_TYPE (function->type ()));
/* Remember only non-void return types. */
if (ret_type->code () != TYPE_CODE_VOID)
{
/* Ignore Python errors at this stage. */
value *func_value = read_var_value (function, NULL, frame);
self_bpfinish->function_value
= value_to_value_object (func_value);
PyErr_Clear ();
self_bpfinish->func_symbol
= symbol_to_symbol_object (function);
PyErr_Clear ();
}
}
}
}
catch (const gdb_exception &except)
{
/* Just swallow. Either the return type or the function value
remain NULL. */
}
if (self_bpfinish->func_symbol == nullptr
|| self_bpfinish->function_value == nullptr)
{
/* Won't be able to compute return value. */
Py_XDECREF (self_bpfinish->func_symbol);
Py_XDECREF (self_bpfinish->function_value);
self_bpfinish->func_symbol = nullptr;
self_bpfinish->function_value = nullptr;
}
bppy_pending_object = &self_bpfinish->py_bp;
bppy_pending_object->number = -1;
bppy_pending_object->bp = NULL;
try
{
/* Set a breakpoint on the return address. */
event_location_up location
= new_address_location (get_frame_pc (prev_frame), NULL, 0);
create_breakpoint (gdbpy_enter::get_gdbarch (),
location.get (), NULL, thread, NULL, false,
0,
1 /*temp_flag*/,
bp_breakpoint,
0,
AUTO_BOOLEAN_TRUE,
&bkpt_breakpoint_ops,
0, 1, internal_bp, 0);
}
catch (const gdb_exception &except)
{
GDB_PY_SET_HANDLE_EXCEPTION (except);
}
self_bpfinish->py_bp.bp->frame_id = frame_id;
self_bpfinish->py_bp.is_finish_bp = 1;
/* Bind the breakpoint with the current program space. */
self_bpfinish->py_bp.bp->pspace = current_program_space;
return 0;
}
/* Called when GDB notices that the finish breakpoint BP_OBJ is out of
the current callstack. Triggers the method OUT_OF_SCOPE if implemented,
then delete the breakpoint. */
static void
bpfinishpy_out_of_scope (struct finish_breakpoint_object *bpfinish_obj)
{
gdbpy_breakpoint_object *bp_obj = (gdbpy_breakpoint_object *) bpfinish_obj;
PyObject *py_obj = (PyObject *) bp_obj;
if (bpfinish_obj->py_bp.bp->enable_state == bp_enabled
&& PyObject_HasAttrString (py_obj, outofscope_func))
{
gdbpy_ref<> meth_result (PyObject_CallMethod (py_obj, outofscope_func,
NULL));
if (meth_result == NULL)
gdbpy_print_stack ();
}
delete_breakpoint (bpfinish_obj->py_bp.bp);
}
/* Callback for `bpfinishpy_detect_out_scope'. Triggers Python's
`B->out_of_scope' function if B is a FinishBreakpoint out of its scope. */
static void
bpfinishpy_detect_out_scope_cb (struct breakpoint *b,
struct breakpoint *bp_stopped)
{
PyObject *py_bp = (PyObject *) b->py_bp_object;
/* Trigger out_of_scope if this is a FinishBreakpoint and its frame is
not anymore in the current callstack. */
if (py_bp != NULL && b->py_bp_object->is_finish_bp)
{
struct finish_breakpoint_object *finish_bp =
(struct finish_breakpoint_object *) py_bp;
/* Check scope if not currently stopped at the FinishBreakpoint. */
if (b != bp_stopped)
{
try
{
if (b->pspace == current_inferior ()->pspace
&& (!target_has_registers ()
|| frame_find_by_id (b->frame_id) == NULL))
bpfinishpy_out_of_scope (finish_bp);
}
catch (const gdb_exception &except)
{
gdbpy_convert_exception (except);
gdbpy_print_stack ();
}
}
}
}
/* Attached to `stop' notifications, check if the execution has run
out of the scope of any FinishBreakpoint before it has been hit. */
static void
bpfinishpy_handle_stop (struct bpstat *bs, int print_frame)
{
gdbpy_enter enter_py;
for (breakpoint *bp : all_breakpoints_safe ())
bpfinishpy_detect_out_scope_cb (bp, bs == NULL ? NULL : bs->breakpoint_at);
}
/* Attached to `exit' notifications, triggers all the necessary out of
scope notifications. */
static void
bpfinishpy_handle_exit (struct inferior *inf)
{
gdbpy_enter enter_py (target_gdbarch ());
for (breakpoint *bp : all_breakpoints_safe ())
bpfinishpy_detect_out_scope_cb (bp, nullptr);
}
/* Initialize the Python finish breakpoint code. */
int
gdbpy_initialize_finishbreakpoints (void)
{
if (PyType_Ready (&finish_breakpoint_object_type) < 0)
return -1;
if (gdb_pymodule_addobject (gdb_module, "FinishBreakpoint",
(PyObject *) &finish_breakpoint_object_type) < 0)
return -1;
gdb::observers::normal_stop.attach (bpfinishpy_handle_stop,
"py-finishbreakpoint");
gdb::observers::inferior_exit.attach (bpfinishpy_handle_exit,
"py-finishbreakpoint");
return 0;
}
static gdb_PyGetSetDef finish_breakpoint_object_getset[] = {
{ "return_value", bpfinishpy_get_returnvalue, NULL,
"gdb.Value object representing the return value, if any. \
None otherwise.", NULL },
{ NULL } /* Sentinel. */
};
PyTypeObject finish_breakpoint_object_type =
{
PyVarObject_HEAD_INIT (NULL, 0)
"gdb.FinishBreakpoint", /*tp_name*/
sizeof (struct finish_breakpoint_object), /*tp_basicsize*/
0, /*tp_itemsize*/
bpfinishpy_dealloc, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
0, /*tp_repr*/
0, /*tp_as_number*/
0, /*tp_as_sequence*/
0, /*tp_as_mapping*/
0, /*tp_hash */
0, /*tp_call*/
0, /*tp_str*/
0, /*tp_getattro*/
0, /*tp_setattro */
0, /*tp_as_buffer*/
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
"GDB finish breakpoint object", /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */
0, /* tp_members */
finish_breakpoint_object_getset,/* tp_getset */
&breakpoint_object_type, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
bpfinishpy_init, /* tp_init */
0, /* tp_alloc */
0 /* tp_new */
};
|