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cc72b2a2 KP |
1 | /* Python interface to finish breakpoints |
2 | ||
0b302171 | 3 | Copyright (C) 2011-2012 Free Software Foundation, Inc. |
cc72b2a2 KP |
4 | |
5 | This file is part of GDB. | |
6 | ||
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. | |
11 | ||
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. | |
16 | ||
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/>. */ | |
19 | ||
20 | ||
21 | ||
22 | #include "defs.h" | |
23 | #include "exceptions.h" | |
24 | #include "python-internal.h" | |
25 | #include "breakpoint.h" | |
26 | #include "frame.h" | |
27 | #include "gdbthread.h" | |
28 | #include "arch-utils.h" | |
29 | #include "language.h" | |
30 | #include "observer.h" | |
31 | #include "inferior.h" | |
6a3a010b | 32 | #include "block.h" |
cc72b2a2 KP |
33 | |
34 | static PyTypeObject finish_breakpoint_object_type; | |
35 | ||
36 | /* Function that is called when a Python finish bp is found out of scope. */ | |
37 | static char * const outofscope_func = "out_of_scope"; | |
38 | ||
39 | /* struct implementing the gdb.FinishBreakpoint object by extending | |
40 | the gdb.Breakpoint class. */ | |
41 | struct finish_breakpoint_object | |
42 | { | |
43 | /* gdb.Breakpoint base class. */ | |
44 | breakpoint_object py_bp; | |
45 | /* gdb.Type object of the value return by the breakpointed function. | |
46 | May be NULL if no debug information was available or return type | |
47 | was VOID. */ | |
48 | PyObject *return_type; | |
6a3a010b | 49 | /* gdb.Value object of the function finished by this breakpoint. Will be |
cc72b2a2 | 50 | NULL if return_type is NULL. */ |
6a3a010b | 51 | PyObject *function_value; |
cc72b2a2 KP |
52 | /* When stopped at this FinishBreakpoint, gdb.Value object returned by |
53 | the function; Py_None if the value is not computable; NULL if GDB is | |
54 | not stopped at a FinishBreakpoint. */ | |
55 | PyObject *return_value; | |
56 | }; | |
57 | ||
58 | /* Python function to get the 'return_value' attribute of | |
59 | FinishBreakpoint. */ | |
60 | ||
61 | static PyObject * | |
62 | bpfinishpy_get_returnvalue (PyObject *self, void *closure) | |
63 | { | |
64 | struct finish_breakpoint_object *self_finishbp = | |
65 | (struct finish_breakpoint_object *) self; | |
66 | ||
67 | if (!self_finishbp->return_value) | |
68 | Py_RETURN_NONE; | |
69 | ||
70 | Py_INCREF (self_finishbp->return_value); | |
71 | return self_finishbp->return_value; | |
72 | } | |
73 | ||
74 | /* Deallocate FinishBreakpoint object. */ | |
75 | ||
76 | static void | |
77 | bpfinishpy_dealloc (PyObject *self) | |
78 | { | |
79 | struct finish_breakpoint_object *self_bpfinish = | |
80 | (struct finish_breakpoint_object *) self; | |
81 | ||
6a3a010b | 82 | Py_XDECREF (self_bpfinish->function_value); |
cc72b2a2 KP |
83 | Py_XDECREF (self_bpfinish->return_type); |
84 | Py_XDECREF (self_bpfinish->return_value); | |
85 | } | |
86 | ||
87 | /* Triggered when gdbpy_should_stop is about to execute the `stop' callback | |
88 | of the gdb.FinishBreakpoint object BP_OBJ. Will compute and cache the | |
89 | `return_value', if possible. */ | |
90 | ||
91 | void | |
92 | bpfinishpy_pre_stop_hook (struct breakpoint_object *bp_obj) | |
93 | { | |
94 | struct finish_breakpoint_object *self_finishbp = | |
95 | (struct finish_breakpoint_object *) bp_obj; | |
96 | volatile struct gdb_exception except; | |
97 | ||
98 | /* Can compute return_value only once. */ | |
99 | gdb_assert (!self_finishbp->return_value); | |
100 | ||
101 | if (!self_finishbp->return_type) | |
102 | return; | |
103 | ||
104 | TRY_CATCH (except, RETURN_MASK_ALL) | |
105 | { | |
6a3a010b MR |
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); | |
cc72b2a2 KP |
111 | |
112 | if (ret) | |
113 | { | |
114 | self_finishbp->return_value = value_to_value_object (ret); | |
115 | if (!self_finishbp->return_value) | |
116 | gdbpy_print_stack (); | |
117 | } | |
118 | else | |
119 | { | |
120 | Py_INCREF (Py_None); | |
121 | self_finishbp->return_value = Py_None; | |
122 | } | |
123 | } | |
124 | if (except.reason < 0) | |
125 | { | |
126 | gdbpy_convert_exception (except); | |
127 | gdbpy_print_stack (); | |
128 | } | |
129 | } | |
130 | ||
131 | /* Triggered when gdbpy_should_stop has triggered the `stop' callback | |
132 | of the gdb.FinishBreakpoint object BP_OBJ. */ | |
133 | ||
134 | void | |
135 | bpfinishpy_post_stop_hook (struct breakpoint_object *bp_obj) | |
136 | { | |
137 | volatile struct gdb_exception except; | |
138 | ||
139 | TRY_CATCH (except, RETURN_MASK_ALL) | |
140 | { | |
141 | /* Can't delete it here, but it will be removed at the next stop. */ | |
142 | disable_breakpoint (bp_obj->bp); | |
143 | gdb_assert (bp_obj->bp->disposition == disp_del); | |
144 | } | |
145 | if (except.reason < 0) | |
146 | { | |
147 | gdbpy_convert_exception (except); | |
148 | gdbpy_print_stack (); | |
149 | } | |
150 | } | |
151 | ||
152 | /* Python function to create a new breakpoint. */ | |
153 | ||
154 | static int | |
155 | bpfinishpy_init (PyObject *self, PyObject *args, PyObject *kwargs) | |
156 | { | |
157 | static char *keywords[] = { "frame", "internal", NULL }; | |
158 | struct finish_breakpoint_object *self_bpfinish = | |
159 | (struct finish_breakpoint_object *) self; | |
160 | int type = bp_breakpoint; | |
161 | PyObject *frame_obj = NULL; | |
162 | int thread; | |
163 | struct frame_info *frame, *prev_frame = NULL; | |
164 | struct frame_id frame_id; | |
165 | PyObject *internal = NULL; | |
166 | int internal_bp = 0; | |
167 | CORE_ADDR finish_pc, pc; | |
168 | volatile struct gdb_exception except; | |
169 | char *addr_str, small_buf[100]; | |
170 | struct symbol *function; | |
171 | ||
172 | if (!PyArg_ParseTupleAndKeywords (args, kwargs, "|OO", keywords, | |
173 | &frame_obj, &internal)) | |
174 | return -1; | |
175 | ||
176 | /* Default frame to gdb.newest_frame if necessary. */ | |
177 | if (!frame_obj) | |
178 | frame_obj = gdbpy_newest_frame (NULL, NULL); | |
179 | else | |
180 | Py_INCREF (frame_obj); | |
181 | ||
182 | frame = frame_object_to_frame_info (frame_obj); | |
183 | Py_DECREF (frame_obj); | |
184 | ||
185 | if (frame == NULL) | |
186 | goto invalid_frame; | |
187 | ||
188 | TRY_CATCH (except, RETURN_MASK_ALL) | |
189 | { | |
190 | prev_frame = get_prev_frame (frame); | |
191 | if (prev_frame == 0) | |
192 | { | |
193 | PyErr_SetString (PyExc_ValueError, _("\"FinishBreakpoint\" not " \ | |
194 | "meaningful in the outermost "\ | |
195 | "frame.")); | |
196 | } | |
197 | else if (get_frame_type (prev_frame) == DUMMY_FRAME) | |
198 | { | |
199 | PyErr_SetString (PyExc_ValueError, _("\"FinishBreakpoint\" cannot "\ | |
200 | "be set on a dummy frame.")); | |
201 | } | |
202 | else | |
203 | { | |
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.")); | |
208 | } | |
209 | } | |
210 | if (except.reason < 0) | |
211 | { | |
212 | gdbpy_convert_exception (except); | |
213 | return -1; | |
214 | } | |
215 | else if (PyErr_Occurred ()) | |
216 | return -1; | |
217 | ||
218 | thread = pid_to_thread_id (inferior_ptid); | |
219 | if (thread == 0) | |
220 | { | |
221 | PyErr_SetString (PyExc_ValueError, | |
222 | _("No thread currently selected.")); | |
223 | return -1; | |
224 | } | |
225 | ||
226 | if (internal) | |
227 | { | |
228 | internal_bp = PyObject_IsTrue (internal); | |
229 | if (internal_bp == -1) | |
230 | { | |
231 | PyErr_SetString (PyExc_ValueError, | |
232 | _("The value of `internal' must be a boolean.")); | |
233 | return -1; | |
234 | } | |
235 | } | |
236 | ||
237 | /* Find the function we will return from. */ | |
238 | self_bpfinish->return_type = NULL; | |
6a3a010b | 239 | self_bpfinish->function_value = NULL; |
cc72b2a2 KP |
240 | |
241 | TRY_CATCH (except, RETURN_MASK_ALL) | |
242 | { | |
243 | if (get_frame_pc_if_available (frame, &pc)) | |
244 | { | |
245 | function = find_pc_function (pc); | |
246 | if (function != NULL) | |
247 | { | |
248 | struct type *ret_type = | |
249 | TYPE_TARGET_TYPE (SYMBOL_TYPE (function)); | |
250 | ||
251 | /* Remember only non-void return types. */ | |
252 | if (TYPE_CODE (ret_type) != TYPE_CODE_VOID) | |
253 | { | |
6a3a010b MR |
254 | struct value *func_value; |
255 | ||
cc72b2a2 KP |
256 | /* Ignore Python errors at this stage. */ |
257 | self_bpfinish->return_type = type_to_type_object (ret_type); | |
258 | PyErr_Clear (); | |
6a3a010b MR |
259 | func_value = read_var_value (function, frame); |
260 | self_bpfinish->function_value = | |
261 | value_to_value_object (func_value); | |
cc72b2a2 KP |
262 | PyErr_Clear (); |
263 | } | |
264 | } | |
265 | } | |
266 | } | |
267 | if (except.reason < 0 | |
6a3a010b | 268 | || !self_bpfinish->return_type || !self_bpfinish->function_value) |
cc72b2a2 KP |
269 | { |
270 | /* Won't be able to compute return value. */ | |
271 | Py_XDECREF (self_bpfinish->return_type); | |
6a3a010b | 272 | Py_XDECREF (self_bpfinish->function_value); |
cc72b2a2 KP |
273 | |
274 | self_bpfinish->return_type = NULL; | |
6a3a010b | 275 | self_bpfinish->function_value = NULL; |
cc72b2a2 KP |
276 | } |
277 | ||
278 | bppy_pending_object = &self_bpfinish->py_bp; | |
279 | bppy_pending_object->number = -1; | |
280 | bppy_pending_object->bp = NULL; | |
281 | ||
282 | TRY_CATCH (except, RETURN_MASK_ALL) | |
283 | { | |
284 | /* Set a breakpoint on the return address. */ | |
285 | finish_pc = get_frame_pc (prev_frame); | |
41843fe8 | 286 | xsnprintf (small_buf, sizeof (small_buf), "*%s", hex_string (finish_pc)); |
cc72b2a2 KP |
287 | addr_str = small_buf; |
288 | ||
289 | create_breakpoint (python_gdbarch, | |
e7e0cddf | 290 | addr_str, NULL, thread, NULL, |
cc72b2a2 KP |
291 | 0, |
292 | 1 /*temp_flag*/, | |
293 | bp_breakpoint, | |
294 | 0, | |
295 | AUTO_BOOLEAN_TRUE, | |
296 | &bkpt_breakpoint_ops, | |
44f238bb | 297 | 0, 1, internal_bp, 0); |
cc72b2a2 KP |
298 | } |
299 | GDB_PY_SET_HANDLE_EXCEPTION (except); | |
300 | ||
301 | self_bpfinish->py_bp.bp->frame_id = frame_id; | |
302 | self_bpfinish->py_bp.is_finish_bp = 1; | |
303 | ||
304 | /* Bind the breakpoint with the current program space. */ | |
305 | self_bpfinish->py_bp.bp->pspace = current_program_space; | |
306 | ||
307 | return 0; | |
308 | ||
309 | invalid_frame: | |
310 | PyErr_SetString (PyExc_ValueError, | |
311 | _("Invalid ID for the `frame' object.")); | |
312 | return -1; | |
313 | } | |
314 | ||
315 | /* Called when GDB notices that the finish breakpoint BP_OBJ is out of | |
316 | the current callstack. Triggers the method OUT_OF_SCOPE if implemented, | |
317 | then delete the breakpoint. */ | |
318 | ||
319 | static void | |
320 | bpfinishpy_out_of_scope (struct finish_breakpoint_object *bpfinish_obj) | |
321 | { | |
cc72b2a2 KP |
322 | breakpoint_object *bp_obj = (breakpoint_object *) bpfinish_obj; |
323 | PyObject *py_obj = (PyObject *) bp_obj; | |
324 | ||
325 | if (bpfinish_obj->py_bp.bp->enable_state == bp_enabled | |
326 | && PyObject_HasAttrString (py_obj, outofscope_func)) | |
327 | { | |
328 | if (!PyObject_CallMethod (py_obj, outofscope_func, NULL)) | |
329 | gdbpy_print_stack (); | |
330 | } | |
331 | ||
332 | delete_breakpoint (bpfinish_obj->py_bp.bp); | |
333 | } | |
334 | ||
335 | /* Callback for `bpfinishpy_detect_out_scope'. Triggers Python's | |
336 | `B->out_of_scope' function if B is a FinishBreakpoint out of its scope. */ | |
337 | ||
338 | static int | |
339 | bpfinishpy_detect_out_scope_cb (struct breakpoint *b, void *args) | |
340 | { | |
341 | volatile struct gdb_exception except; | |
342 | struct breakpoint *bp_stopped = (struct breakpoint *) args; | |
343 | PyObject *py_bp = (PyObject *) b->py_bp_object; | |
344 | struct gdbarch *garch = b->gdbarch ? b->gdbarch : get_current_arch (); | |
345 | ||
346 | /* Trigger out_of_scope if this is a FinishBreakpoint and its frame is | |
347 | not anymore in the current callstack. */ | |
348 | if (py_bp != NULL && b->py_bp_object->is_finish_bp) | |
349 | { | |
350 | struct finish_breakpoint_object *finish_bp = | |
351 | (struct finish_breakpoint_object *) py_bp; | |
352 | ||
353 | /* Check scope if not currently stopped at the FinishBreakpoint. */ | |
354 | if (b != bp_stopped) | |
355 | { | |
356 | TRY_CATCH (except, RETURN_MASK_ALL) | |
357 | { | |
358 | if (b->pspace == current_inferior ()->pspace | |
359 | && (!target_has_registers | |
360 | || frame_find_by_id (b->frame_id) == NULL)) | |
361 | bpfinishpy_out_of_scope (finish_bp); | |
362 | } | |
363 | if (except.reason < 0) | |
364 | { | |
365 | gdbpy_convert_exception (except); | |
366 | gdbpy_print_stack (); | |
367 | } | |
368 | } | |
369 | } | |
370 | ||
371 | return 0; | |
372 | } | |
373 | ||
374 | /* Attached to `stop' notifications, check if the execution has run | |
375 | out of the scope of any FinishBreakpoint before it has been hit. */ | |
376 | ||
377 | static void | |
378 | bpfinishpy_handle_stop (struct bpstats *bs, int print_frame) | |
379 | { | |
380 | struct cleanup *cleanup = ensure_python_env (get_current_arch (), | |
381 | current_language); | |
382 | ||
383 | iterate_over_breakpoints (bpfinishpy_detect_out_scope_cb, | |
384 | bs == NULL ? NULL : bs->breakpoint_at); | |
385 | ||
386 | do_cleanups (cleanup); | |
387 | } | |
388 | ||
389 | /* Attached to `exit' notifications, triggers all the necessary out of | |
390 | scope notifications. */ | |
391 | ||
392 | static void | |
393 | bpfinishpy_handle_exit (struct inferior *inf) | |
394 | { | |
f5656ead | 395 | struct cleanup *cleanup = ensure_python_env (target_gdbarch (), |
cc72b2a2 KP |
396 | current_language); |
397 | ||
398 | iterate_over_breakpoints (bpfinishpy_detect_out_scope_cb, NULL); | |
399 | ||
400 | do_cleanups (cleanup); | |
401 | } | |
402 | ||
403 | /* Initialize the Python finish breakpoint code. */ | |
404 | ||
405 | void | |
406 | gdbpy_initialize_finishbreakpoints (void) | |
407 | { | |
408 | if (PyType_Ready (&finish_breakpoint_object_type) < 0) | |
409 | return; | |
410 | ||
411 | Py_INCREF (&finish_breakpoint_object_type); | |
412 | PyModule_AddObject (gdb_module, "FinishBreakpoint", | |
413 | (PyObject *) &finish_breakpoint_object_type); | |
414 | ||
415 | observer_attach_normal_stop (bpfinishpy_handle_stop); | |
416 | observer_attach_inferior_exit (bpfinishpy_handle_exit); | |
417 | } | |
418 | ||
419 | static 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. */ | |
424 | }; | |
425 | ||
426 | static PyTypeObject finish_breakpoint_object_type = | |
427 | { | |
428 | PyObject_HEAD_INIT (NULL) | |
429 | 0, /*ob_size*/ | |
430 | "gdb.FinishBreakpoint", /*tp_name*/ | |
431 | sizeof (struct finish_breakpoint_object), /*tp_basicsize*/ | |
432 | 0, /*tp_itemsize*/ | |
433 | bpfinishpy_dealloc, /*tp_dealloc*/ | |
434 | 0, /*tp_print*/ | |
435 | 0, /*tp_getattr*/ | |
436 | 0, /*tp_setattr*/ | |
437 | 0, /*tp_compare*/ | |
438 | 0, /*tp_repr*/ | |
439 | 0, /*tp_as_number*/ | |
440 | 0, /*tp_as_sequence*/ | |
441 | 0, /*tp_as_mapping*/ | |
442 | 0, /*tp_hash */ | |
443 | 0, /*tp_call*/ | |
444 | 0, /*tp_str*/ | |
445 | 0, /*tp_getattro*/ | |
446 | 0, /*tp_setattro */ | |
447 | 0, /*tp_as_buffer*/ | |
448 | Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/ | |
449 | "GDB finish breakpoint object", /* tp_doc */ | |
450 | 0, /* tp_traverse */ | |
451 | 0, /* tp_clear */ | |
452 | 0, /* tp_richcompare */ | |
453 | 0, /* tp_weaklistoffset */ | |
454 | 0, /* tp_iter */ | |
455 | 0, /* tp_iternext */ | |
456 | 0, /* tp_methods */ | |
457 | 0, /* tp_members */ | |
458 | finish_breakpoint_object_getset,/* tp_getset */ | |
459 | &breakpoint_object_type, /* tp_base */ | |
460 | 0, /* tp_dict */ | |
461 | 0, /* tp_descr_get */ | |
462 | 0, /* tp_descr_set */ | |
463 | 0, /* tp_dictoffset */ | |
464 | bpfinishpy_init, /* tp_init */ | |
465 | 0, /* tp_alloc */ | |
466 | 0 /* tp_new */ | |
467 | }; |