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f8f6f20b TJB |
1 | /* Python interface to stack frames |
2 | ||
3 | Copyright (C) 2008, 2009 Free Software Foundation, Inc. | |
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 | #include "defs.h" | |
21 | #include "charset.h" | |
22 | #include "block.h" | |
23 | #include "frame.h" | |
24 | #include "exceptions.h" | |
25 | #include "symtab.h" | |
26 | #include "stack.h" | |
27 | #include "value.h" | |
28 | #include "python-internal.h" | |
29 | ||
30 | typedef struct { | |
31 | PyObject_HEAD | |
32 | struct frame_id frame_id; | |
33 | struct gdbarch *gdbarch; | |
34 | ||
35 | /* Marks that the FRAME_ID member actually holds the ID of the frame next | |
36 | to this, and not this frames' ID itself. This is a hack to permit Python | |
37 | frame objects which represent invalid frames (i.e., the last frame_info | |
38 | in a corrupt stack). The problem arises from the fact that this code | |
39 | relies on FRAME_ID to uniquely identify a frame, which is not always true | |
40 | for the last "frame" in a corrupt stack (it can have a null ID, or the same | |
41 | ID as the previous frame). Whenever get_prev_frame returns NULL, we | |
42 | record the frame_id of the next frame and set FRAME_ID_IS_NEXT to 1. */ | |
43 | int frame_id_is_next; | |
44 | } frame_object; | |
45 | ||
46 | /* Require a valid frame. This must be called inside a TRY_CATCH, or | |
47 | another context in which a gdb exception is allowed. */ | |
48 | #define FRAPY_REQUIRE_VALID(frame_obj, frame) \ | |
49 | do { \ | |
50 | frame = frame_object_to_frame_info (frame_obj); \ | |
51 | if (frame == NULL) \ | |
52 | error ("Frame is invalid."); \ | |
53 | } while (0) | |
54 | ||
55 | static PyTypeObject frame_object_type; | |
56 | ||
57 | /* Returns the frame_info object corresponding to the given Python Frame | |
58 | object. If the frame doesn't exist anymore (the frame id doesn't | |
59 | correspond to any frame in the inferior), returns NULL. */ | |
60 | ||
61 | static struct frame_info * | |
62 | frame_object_to_frame_info (frame_object *frame_obj) | |
63 | { | |
64 | struct frame_info *frame; | |
65 | ||
66 | frame = frame_find_by_id (frame_obj->frame_id); | |
67 | if (frame == NULL) | |
68 | return NULL; | |
69 | ||
70 | if (frame_obj->frame_id_is_next) | |
71 | frame = get_prev_frame (frame); | |
72 | ||
73 | return frame; | |
74 | } | |
75 | ||
76 | /* Called by the Python interpreter to obtain string representation | |
77 | of the object. */ | |
78 | ||
79 | static PyObject * | |
80 | frapy_str (PyObject *self) | |
81 | { | |
82 | char *s; | |
f8f6f20b TJB |
83 | PyObject *result; |
84 | struct ui_file *strfile; | |
85 | ||
86 | strfile = mem_fileopen (); | |
87 | fprint_frame_id (strfile, ((frame_object *) self)->frame_id); | |
759ef836 | 88 | s = ui_file_xstrdup (strfile, NULL); |
f8f6f20b TJB |
89 | result = PyString_FromString (s); |
90 | xfree (s); | |
91 | ||
92 | return result; | |
93 | } | |
94 | ||
95 | /* Implementation of gdb.Frame.is_valid (self) -> Boolean. | |
96 | Returns True if the frame corresponding to the frame_id of this | |
97 | object still exists in the inferior. */ | |
98 | ||
99 | static PyObject * | |
100 | frapy_is_valid (PyObject *self, PyObject *args) | |
101 | { | |
102 | struct frame_info *frame; | |
103 | ||
104 | frame = frame_object_to_frame_info ((frame_object *) self); | |
105 | if (frame == NULL) | |
106 | Py_RETURN_FALSE; | |
107 | ||
108 | Py_RETURN_TRUE; | |
109 | } | |
110 | ||
111 | /* Implementation of gdb.Frame.name (self) -> String. | |
112 | Returns the name of the function corresponding to this frame. */ | |
113 | ||
114 | static PyObject * | |
115 | frapy_name (PyObject *self, PyObject *args) | |
116 | { | |
117 | struct frame_info *frame; | |
118 | char *name; | |
119 | enum language lang; | |
120 | PyObject *result; | |
121 | volatile struct gdb_exception except; | |
122 | ||
123 | TRY_CATCH (except, RETURN_MASK_ALL) | |
124 | { | |
125 | FRAPY_REQUIRE_VALID ((frame_object *) self, frame); | |
126 | ||
127 | find_frame_funname (frame, &name, &lang); | |
128 | } | |
129 | GDB_PY_HANDLE_EXCEPTION (except); | |
130 | ||
131 | if (name) | |
132 | result = PyUnicode_Decode (name, strlen (name), host_charset (), NULL); | |
133 | else | |
134 | { | |
135 | result = Py_None; | |
136 | Py_INCREF (Py_None); | |
137 | } | |
138 | ||
139 | return result; | |
140 | } | |
141 | ||
142 | /* Implementation of gdb.Frame.type (self) -> Integer. | |
143 | Returns the frame type, namely one of the gdb.*_FRAME constants. */ | |
144 | ||
145 | static PyObject * | |
146 | frapy_type (PyObject *self, PyObject *args) | |
147 | { | |
148 | struct frame_info *frame; | |
149 | enum frame_type type = NORMAL_FRAME;/* Initialize to appease gcc warning. */ | |
150 | volatile struct gdb_exception except; | |
151 | ||
152 | TRY_CATCH (except, RETURN_MASK_ALL) | |
153 | { | |
154 | FRAPY_REQUIRE_VALID ((frame_object *) self, frame); | |
155 | ||
156 | type = get_frame_type (frame); | |
157 | } | |
158 | GDB_PY_HANDLE_EXCEPTION (except); | |
159 | ||
160 | return PyInt_FromLong (type); | |
161 | } | |
162 | ||
163 | /* Implementation of gdb.Frame.unwind_stop_reason (self) -> Integer. | |
164 | Returns one of the gdb.FRAME_UNWIND_* constants. */ | |
165 | ||
166 | static PyObject * | |
167 | frapy_unwind_stop_reason (PyObject *self, PyObject *args) | |
168 | { | |
169 | struct frame_info *frame = NULL; /* Initialize to appease gcc warning. */ | |
170 | volatile struct gdb_exception except; | |
171 | enum unwind_stop_reason stop_reason; | |
172 | ||
173 | TRY_CATCH (except, RETURN_MASK_ALL) | |
174 | { | |
175 | FRAPY_REQUIRE_VALID ((frame_object *) self, frame); | |
176 | } | |
177 | GDB_PY_HANDLE_EXCEPTION (except); | |
178 | ||
179 | stop_reason = get_frame_unwind_stop_reason (frame); | |
180 | ||
181 | return PyInt_FromLong (stop_reason); | |
182 | } | |
183 | ||
184 | /* Implementation of gdb.Frame.pc (self) -> Long. | |
185 | Returns the frame's resume address. */ | |
186 | ||
187 | static PyObject * | |
188 | frapy_pc (PyObject *self, PyObject *args) | |
189 | { | |
190 | CORE_ADDR pc = 0; /* Initialize to appease gcc warning. */ | |
191 | struct frame_info *frame; | |
192 | volatile struct gdb_exception except; | |
193 | ||
194 | TRY_CATCH (except, RETURN_MASK_ALL) | |
195 | { | |
196 | FRAPY_REQUIRE_VALID ((frame_object *) self, frame); | |
197 | ||
198 | pc = get_frame_pc (frame); | |
199 | } | |
200 | GDB_PY_HANDLE_EXCEPTION (except); | |
201 | ||
202 | return PyLong_FromUnsignedLongLong (pc); | |
203 | } | |
204 | ||
205 | /* Convert a frame_info struct to a Python Frame object. | |
206 | Sets a Python exception and returns NULL on error. */ | |
207 | ||
208 | static frame_object * | |
209 | frame_info_to_frame_object (struct frame_info *frame) | |
210 | { | |
211 | frame_object *frame_obj; | |
212 | ||
213 | frame_obj = PyObject_New (frame_object, &frame_object_type); | |
214 | if (frame_obj == NULL) | |
215 | { | |
216 | PyErr_SetString (PyExc_MemoryError, "Could not allocate frame object."); | |
217 | return NULL; | |
218 | } | |
219 | ||
220 | /* Try to get the previous frame, to determine if this is the last frame | |
221 | in a corrupt stack. If so, we need to store the frame_id of the next | |
222 | frame and not of this one (which is possibly invalid). */ | |
223 | if (get_prev_frame (frame) == NULL | |
224 | && get_frame_unwind_stop_reason (frame) != UNWIND_NO_REASON | |
225 | && get_next_frame (frame) != NULL) | |
226 | { | |
227 | frame_obj->frame_id = get_frame_id (get_next_frame (frame)); | |
228 | frame_obj->frame_id_is_next = 1; | |
229 | } | |
230 | else | |
231 | { | |
232 | frame_obj->frame_id = get_frame_id (frame); | |
233 | frame_obj->frame_id_is_next = 0; | |
234 | } | |
235 | ||
236 | frame_obj->gdbarch = get_frame_arch (frame); | |
237 | ||
238 | return frame_obj; | |
239 | } | |
240 | ||
241 | /* Implementation of gdb.Frame.older (self) -> gdb.Frame. | |
242 | Returns the frame immediately older (outer) to this frame, or None if | |
243 | there isn't one. */ | |
244 | ||
245 | static PyObject * | |
246 | frapy_older (PyObject *self, PyObject *args) | |
247 | { | |
248 | struct frame_info *frame, *prev; | |
249 | volatile struct gdb_exception except; | |
250 | PyObject *prev_obj = NULL; /* Initialize to appease gcc warning. */ | |
251 | ||
252 | TRY_CATCH (except, RETURN_MASK_ALL) | |
253 | { | |
254 | FRAPY_REQUIRE_VALID ((frame_object *) self, frame); | |
255 | ||
256 | prev = get_prev_frame (frame); | |
257 | if (prev) | |
258 | prev_obj = (PyObject *) frame_info_to_frame_object (prev); | |
259 | else | |
260 | { | |
261 | Py_INCREF (Py_None); | |
262 | prev_obj = Py_None; | |
263 | } | |
264 | } | |
265 | GDB_PY_HANDLE_EXCEPTION (except); | |
266 | ||
267 | return prev_obj; | |
268 | } | |
269 | ||
270 | /* Implementation of gdb.Frame.newer (self) -> gdb.Frame. | |
271 | Returns the frame immediately newer (inner) to this frame, or None if | |
272 | there isn't one. */ | |
273 | ||
274 | static PyObject * | |
275 | frapy_newer (PyObject *self, PyObject *args) | |
276 | { | |
277 | struct frame_info *frame, *next; | |
278 | volatile struct gdb_exception except; | |
279 | PyObject *next_obj = NULL; /* Initialize to appease gcc warning. */ | |
280 | ||
281 | TRY_CATCH (except, RETURN_MASK_ALL) | |
282 | { | |
283 | FRAPY_REQUIRE_VALID ((frame_object *) self, frame); | |
284 | ||
285 | next = get_next_frame (frame); | |
286 | if (next) | |
287 | next_obj = (PyObject *) frame_info_to_frame_object (next); | |
288 | else | |
289 | { | |
290 | Py_INCREF (Py_None); | |
291 | next_obj = Py_None; | |
292 | } | |
293 | } | |
294 | GDB_PY_HANDLE_EXCEPTION (except); | |
295 | ||
296 | return next_obj; | |
297 | } | |
298 | ||
299 | /* Implementation of gdb.Frame.read_var_value (self, variable) -> gdb.Value. | |
300 | Returns the value of the given variable in this frame. The argument must be | |
301 | a string. Returns None if GDB can't find the specified variable. */ | |
302 | ||
303 | static PyObject * | |
304 | frapy_read_var (PyObject *self, PyObject *args) | |
305 | { | |
306 | struct frame_info *frame; | |
307 | PyObject *sym_obj; | |
308 | struct symbol *var = NULL; /* gcc-4.3.2 false warning. */ | |
309 | struct value *val = NULL; | |
310 | volatile struct gdb_exception except; | |
311 | ||
312 | if (!PyArg_ParseTuple (args, "O", &sym_obj)) | |
313 | return NULL; | |
314 | ||
315 | if (gdbpy_is_string (sym_obj)) | |
316 | { | |
317 | char *var_name; | |
318 | struct block *block = NULL; | |
319 | struct cleanup *cleanup; | |
320 | volatile struct gdb_exception except; | |
321 | ||
322 | var_name = python_string_to_target_string (sym_obj); | |
323 | if (!var_name) | |
324 | return NULL; | |
325 | cleanup = make_cleanup (xfree, var_name); | |
326 | ||
327 | TRY_CATCH (except, RETURN_MASK_ALL) | |
328 | { | |
329 | FRAPY_REQUIRE_VALID ((frame_object *) self, frame); | |
330 | ||
331 | block = block_for_pc (get_frame_address_in_block (frame)); | |
332 | var = lookup_symbol (var_name, block, VAR_DOMAIN, NULL); | |
333 | } | |
334 | GDB_PY_HANDLE_EXCEPTION (except); | |
335 | ||
336 | if (!var) | |
337 | { | |
338 | PyErr_Format (PyExc_ValueError, | |
339 | _("variable '%s' not found"), var_name); | |
340 | do_cleanups (cleanup); | |
341 | ||
342 | return NULL; | |
343 | } | |
344 | ||
345 | do_cleanups (cleanup); | |
346 | } | |
347 | else | |
348 | { | |
349 | PyErr_SetString (PyExc_TypeError, | |
350 | _("argument must be a symbol or string")); | |
351 | return NULL; | |
352 | } | |
353 | ||
354 | TRY_CATCH (except, RETURN_MASK_ALL) | |
355 | { | |
356 | FRAPY_REQUIRE_VALID ((frame_object *) self, frame); | |
357 | ||
358 | val = read_var_value (var, frame); | |
359 | } | |
360 | GDB_PY_HANDLE_EXCEPTION (except); | |
361 | ||
362 | if (val) | |
363 | return value_to_value_object (val); | |
364 | ||
365 | Py_RETURN_NONE; | |
366 | } | |
367 | ||
368 | /* Implementation of gdb.selected_frame () -> gdb.Frame. | |
369 | Returns the selected frame object. */ | |
370 | ||
371 | PyObject * | |
372 | gdbpy_selected_frame (PyObject *self, PyObject *args) | |
373 | { | |
374 | struct frame_info *frame; | |
375 | frame_object *frame_obj = NULL; /* Initialize to appease gcc warning. */ | |
376 | volatile struct gdb_exception except; | |
377 | ||
378 | TRY_CATCH (except, RETURN_MASK_ALL) | |
379 | { | |
380 | frame = get_selected_frame ("No frame is currently selected."); | |
381 | frame_obj = frame_info_to_frame_object (frame); | |
382 | } | |
383 | GDB_PY_HANDLE_EXCEPTION (except); | |
384 | ||
385 | return (PyObject *) frame_obj; | |
386 | } | |
387 | ||
388 | /* Implementation of gdb.stop_reason_string (Integer) -> String. | |
389 | Return a string explaining the unwind stop reason. */ | |
390 | ||
391 | PyObject * | |
392 | gdbpy_frame_stop_reason_string (PyObject *self, PyObject *args) | |
393 | { | |
394 | int reason; | |
395 | const char *str; | |
396 | ||
397 | if (!PyArg_ParseTuple (args, "i", &reason)) | |
398 | return NULL; | |
399 | ||
400 | if (reason < 0 || reason > UNWIND_NO_SAVED_PC) | |
401 | { | |
402 | PyErr_SetString (PyExc_ValueError, "Invalid frame stop reason."); | |
403 | return NULL; | |
404 | } | |
405 | ||
406 | str = frame_stop_reason_string (reason); | |
407 | return PyUnicode_Decode (str, strlen (str), host_charset (), NULL); | |
408 | } | |
409 | ||
410 | /* Implements the equality comparison for Frame objects. | |
411 | All other comparison operators will throw a TypeError Python exception, | |
412 | as they aren't valid for frames. */ | |
413 | ||
414 | static PyObject * | |
415 | frapy_richcompare (PyObject *self, PyObject *other, int op) | |
416 | { | |
18e8c3bc TT |
417 | int result; |
418 | ||
419 | if (!PyObject_TypeCheck (other, &frame_object_type) | |
420 | || (op != Py_EQ && op != Py_NE)) | |
f8f6f20b | 421 | { |
18e8c3bc TT |
422 | Py_INCREF (Py_NotImplemented); |
423 | return Py_NotImplemented; | |
f8f6f20b TJB |
424 | } |
425 | ||
426 | if (frame_id_eq (((frame_object *) self)->frame_id, | |
427 | ((frame_object *) other)->frame_id)) | |
18e8c3bc TT |
428 | result = Py_EQ; |
429 | else | |
430 | result = Py_NE; | |
f8f6f20b | 431 | |
18e8c3bc TT |
432 | if (op == result) |
433 | Py_RETURN_TRUE; | |
f8f6f20b TJB |
434 | Py_RETURN_FALSE; |
435 | } | |
436 | ||
437 | /* Sets up the Frame API in the gdb module. */ | |
438 | ||
439 | void | |
440 | gdbpy_initialize_frames (void) | |
441 | { | |
442 | if (PyType_Ready (&frame_object_type) < 0) | |
443 | return; | |
444 | ||
445 | /* Note: These would probably be best exposed as class attributes of Frame, | |
446 | but I don't know how to do it except by messing with the type's dictionary. | |
447 | That seems too messy. */ | |
448 | PyModule_AddIntConstant (gdb_module, "NORMAL_FRAME", NORMAL_FRAME); | |
449 | PyModule_AddIntConstant (gdb_module, "DUMMY_FRAME", DUMMY_FRAME); | |
450 | PyModule_AddIntConstant (gdb_module, "SIGTRAMP_FRAME", SIGTRAMP_FRAME); | |
451 | PyModule_AddIntConstant (gdb_module, "SENTINEL_FRAME", SENTINEL_FRAME); | |
452 | PyModule_AddIntConstant (gdb_module, | |
453 | "FRAME_UNWIND_NO_REASON", UNWIND_NO_REASON); | |
454 | PyModule_AddIntConstant (gdb_module, | |
455 | "FRAME_UNWIND_NULL_ID", UNWIND_NULL_ID); | |
456 | PyModule_AddIntConstant (gdb_module, | |
457 | "FRAME_UNWIND_FIRST_ERROR", UNWIND_FIRST_ERROR); | |
458 | PyModule_AddIntConstant (gdb_module, | |
459 | "FRAME_UNWIND_INNER_ID", UNWIND_INNER_ID); | |
460 | PyModule_AddIntConstant (gdb_module, | |
461 | "FRAME_UNWIND_SAME_ID", UNWIND_SAME_ID); | |
462 | PyModule_AddIntConstant (gdb_module, | |
463 | "FRAME_UNWIND_NO_SAVED_PC", UNWIND_NO_SAVED_PC); | |
464 | ||
465 | Py_INCREF (&frame_object_type); | |
466 | PyModule_AddObject (gdb_module, "Frame", (PyObject *) &frame_object_type); | |
467 | } | |
468 | ||
469 | \f | |
470 | ||
471 | static PyMethodDef frame_object_methods[] = { | |
472 | { "is_valid", frapy_is_valid, METH_NOARGS, | |
473 | "is_valid () -> Boolean.\n\ | |
474 | Return true if this frame is valid, false if not." }, | |
475 | { "name", frapy_name, METH_NOARGS, | |
476 | "name () -> String.\n\ | |
477 | Return the function name of the frame, or None if it can't be determined." }, | |
478 | { "type", frapy_type, METH_NOARGS, | |
479 | "type () -> Integer.\n\ | |
480 | Return the type of the frame." }, | |
481 | { "unwind_stop_reason", frapy_unwind_stop_reason, METH_NOARGS, | |
482 | "unwind_stop_reason () -> Integer.\n\ | |
483 | Return the reason why it's not possible to find frames older than this." }, | |
484 | { "pc", frapy_pc, METH_NOARGS, | |
485 | "pc () -> Long.\n\ | |
486 | Return the frame's resume address." }, | |
487 | { "older", frapy_older, METH_NOARGS, | |
488 | "older () -> gdb.Frame.\n\ | |
489 | Return the frame that called this frame." }, | |
490 | { "newer", frapy_newer, METH_NOARGS, | |
491 | "newer () -> gdb.Frame.\n\ | |
492 | Return the frame called by this frame." }, | |
493 | { "read_var", frapy_read_var, METH_VARARGS, | |
494 | "read_var (variable) -> gdb.Value.\n\ | |
495 | Return the value of the variable in this frame." }, | |
496 | {NULL} /* Sentinel */ | |
497 | }; | |
498 | ||
499 | static PyTypeObject frame_object_type = { | |
500 | PyObject_HEAD_INIT (NULL) | |
501 | 0, /* ob_size */ | |
502 | "gdb.Frame", /* tp_name */ | |
503 | sizeof (frame_object), /* tp_basicsize */ | |
504 | 0, /* tp_itemsize */ | |
505 | 0, /* tp_dealloc */ | |
506 | 0, /* tp_print */ | |
507 | 0, /* tp_getattr */ | |
508 | 0, /* tp_setattr */ | |
509 | 0, /* tp_compare */ | |
510 | 0, /* tp_repr */ | |
511 | 0, /* tp_as_number */ | |
512 | 0, /* tp_as_sequence */ | |
513 | 0, /* tp_as_mapping */ | |
514 | 0, /* tp_hash */ | |
515 | 0, /* tp_call */ | |
516 | frapy_str, /* tp_str */ | |
517 | 0, /* tp_getattro */ | |
518 | 0, /* tp_setattro */ | |
519 | 0, /* tp_as_buffer */ | |
520 | Py_TPFLAGS_DEFAULT, /* tp_flags */ | |
521 | "GDB frame object", /* tp_doc */ | |
522 | 0, /* tp_traverse */ | |
523 | 0, /* tp_clear */ | |
524 | frapy_richcompare, /* tp_richcompare */ | |
525 | 0, /* tp_weaklistoffset */ | |
526 | 0, /* tp_iter */ | |
527 | 0, /* tp_iternext */ | |
528 | frame_object_methods, /* tp_methods */ | |
529 | 0, /* tp_members */ | |
530 | 0, /* tp_getset */ | |
531 | 0, /* tp_base */ | |
532 | 0, /* tp_dict */ | |
533 | 0, /* tp_descr_get */ | |
534 | 0, /* tp_descr_set */ | |
535 | 0, /* tp_dictoffset */ | |
536 | 0, /* tp_init */ | |
537 | 0, /* tp_alloc */ | |
538 | PyType_GenericNew /* tp_new */ | |
539 | }; |