1 /* Python interface to stack frames
3 Copyright (C) 2008-2014 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/>. */
24 #include "exceptions.h"
28 #include "python-internal.h"
34 struct frame_id frame_id;
35 struct gdbarch *gdbarch;
37 /* Marks that the FRAME_ID member actually holds the ID of the frame next
38 to this, and not this frames' ID itself. This is a hack to permit Python
39 frame objects which represent invalid frames (i.e., the last frame_info
40 in a corrupt stack). The problem arises from the fact that this code
41 relies on FRAME_ID to uniquely identify a frame, which is not always true
42 for the last "frame" in a corrupt stack (it can have a null ID, or the same
43 ID as the previous frame). Whenever get_prev_frame returns NULL, we
44 record the frame_id of the next frame and set FRAME_ID_IS_NEXT to 1. */
48 /* Require a valid frame. This must be called inside a TRY_CATCH, or
49 another context in which a gdb exception is allowed. */
50 #define FRAPY_REQUIRE_VALID(frame_obj, frame) \
52 frame = frame_object_to_frame_info (frame_obj); \
54 error (_("Frame is invalid.")); \
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. */
62 frame_object_to_frame_info (PyObject *obj)
64 frame_object *frame_obj = (frame_object *) obj;
65 struct frame_info *frame;
67 frame = frame_find_by_id (frame_obj->frame_id);
71 if (frame_obj->frame_id_is_next)
72 frame = get_prev_frame (frame);
77 /* Called by the Python interpreter to obtain string representation
81 frapy_str (PyObject *self)
85 struct ui_file *strfile;
87 strfile = mem_fileopen ();
88 fprint_frame_id (strfile, ((frame_object *) self)->frame_id);
89 s = ui_file_xstrdup (strfile, NULL);
90 result = PyString_FromString (s);
96 /* Implementation of gdb.Frame.is_valid (self) -> Boolean.
97 Returns True if the frame corresponding to the frame_id of this
98 object still exists in the inferior. */
101 frapy_is_valid (PyObject *self, PyObject *args)
103 struct frame_info *frame = NULL;
104 volatile struct gdb_exception except;
106 TRY_CATCH (except, RETURN_MASK_ALL)
108 frame = frame_object_to_frame_info (self);
110 GDB_PY_HANDLE_EXCEPTION (except);
118 /* Implementation of gdb.Frame.name (self) -> String.
119 Returns the name of the function corresponding to this frame. */
122 frapy_name (PyObject *self, PyObject *args)
124 struct frame_info *frame;
128 volatile struct gdb_exception except;
130 TRY_CATCH (except, RETURN_MASK_ALL)
132 FRAPY_REQUIRE_VALID (self, frame);
134 find_frame_funname (frame, &name, &lang, NULL);
137 if (except.reason < 0)
140 GDB_PY_HANDLE_EXCEPTION (except);
144 result = PyUnicode_Decode (name, strlen (name), host_charset (), NULL);
156 /* Implementation of gdb.Frame.type (self) -> Integer.
157 Returns the frame type, namely one of the gdb.*_FRAME constants. */
160 frapy_type (PyObject *self, PyObject *args)
162 struct frame_info *frame;
163 enum frame_type type = NORMAL_FRAME;/* Initialize to appease gcc warning. */
164 volatile struct gdb_exception except;
166 TRY_CATCH (except, RETURN_MASK_ALL)
168 FRAPY_REQUIRE_VALID (self, frame);
170 type = get_frame_type (frame);
172 GDB_PY_HANDLE_EXCEPTION (except);
174 return PyInt_FromLong (type);
177 /* Implementation of gdb.Frame.architecture (self) -> gdb.Architecture.
178 Returns the frame's architecture as a gdb.Architecture object. */
181 frapy_arch (PyObject *self, PyObject *args)
183 struct frame_info *frame = NULL; /* Initialize to appease gcc warning. */
184 frame_object *obj = (frame_object *) self;
185 volatile struct gdb_exception except;
187 TRY_CATCH (except, RETURN_MASK_ALL)
189 FRAPY_REQUIRE_VALID (self, frame);
191 GDB_PY_HANDLE_EXCEPTION (except);
193 return gdbarch_to_arch_object (obj->gdbarch);
196 /* Implementation of gdb.Frame.unwind_stop_reason (self) -> Integer.
197 Returns one of the gdb.FRAME_UNWIND_* constants. */
200 frapy_unwind_stop_reason (PyObject *self, PyObject *args)
202 struct frame_info *frame = NULL; /* Initialize to appease gcc warning. */
203 volatile struct gdb_exception except;
204 enum unwind_stop_reason stop_reason;
206 TRY_CATCH (except, RETURN_MASK_ALL)
208 FRAPY_REQUIRE_VALID (self, frame);
210 GDB_PY_HANDLE_EXCEPTION (except);
212 stop_reason = get_frame_unwind_stop_reason (frame);
214 return PyInt_FromLong (stop_reason);
217 /* Implementation of gdb.Frame.pc (self) -> Long.
218 Returns the frame's resume address. */
221 frapy_pc (PyObject *self, PyObject *args)
223 CORE_ADDR pc = 0; /* Initialize to appease gcc warning. */
224 struct frame_info *frame;
225 volatile struct gdb_exception except;
227 TRY_CATCH (except, RETURN_MASK_ALL)
229 FRAPY_REQUIRE_VALID (self, frame);
231 pc = get_frame_pc (frame);
233 GDB_PY_HANDLE_EXCEPTION (except);
235 return gdb_py_long_from_ulongest (pc);
238 /* Implementation of gdb.Frame.block (self) -> gdb.Block.
239 Returns the frame's code block. */
242 frapy_block (PyObject *self, PyObject *args)
244 struct frame_info *frame;
245 struct block *block = NULL, *fn_block;
246 volatile struct gdb_exception except;
248 TRY_CATCH (except, RETURN_MASK_ALL)
250 FRAPY_REQUIRE_VALID (self, frame);
251 block = get_frame_block (frame, NULL);
253 GDB_PY_HANDLE_EXCEPTION (except);
255 for (fn_block = block;
256 fn_block != NULL && BLOCK_FUNCTION (fn_block) == NULL;
257 fn_block = BLOCK_SUPERBLOCK (fn_block))
260 if (block == NULL || fn_block == NULL || BLOCK_FUNCTION (fn_block) == NULL)
262 PyErr_SetString (PyExc_RuntimeError,
263 _("Cannot locate block for frame."));
271 symt = SYMBOL_SYMTAB (BLOCK_FUNCTION (fn_block));
272 return block_to_block_object (block, symt->objfile);
279 /* Implementation of gdb.Frame.function (self) -> gdb.Symbol.
280 Returns the symbol for the function corresponding to this frame. */
283 frapy_function (PyObject *self, PyObject *args)
285 struct symbol *sym = NULL;
286 struct frame_info *frame;
287 volatile struct gdb_exception except;
289 TRY_CATCH (except, RETURN_MASK_ALL)
291 FRAPY_REQUIRE_VALID (self, frame);
293 sym = find_pc_function (get_frame_address_in_block (frame));
295 GDB_PY_HANDLE_EXCEPTION (except);
298 return symbol_to_symbol_object (sym);
303 /* Convert a frame_info struct to a Python Frame object.
304 Sets a Python exception and returns NULL on error. */
307 frame_info_to_frame_object (struct frame_info *frame)
309 frame_object *frame_obj;
310 volatile struct gdb_exception except;
312 frame_obj = PyObject_New (frame_object, &frame_object_type);
313 if (frame_obj == NULL)
316 TRY_CATCH (except, RETURN_MASK_ALL)
319 /* Try to get the previous frame, to determine if this is the last frame
320 in a corrupt stack. If so, we need to store the frame_id of the next
321 frame and not of this one (which is possibly invalid). */
322 if (get_prev_frame (frame) == NULL
323 && get_frame_unwind_stop_reason (frame) != UNWIND_NO_REASON
324 && get_next_frame (frame) != NULL)
326 frame_obj->frame_id = get_frame_id (get_next_frame (frame));
327 frame_obj->frame_id_is_next = 1;
331 frame_obj->frame_id = get_frame_id (frame);
332 frame_obj->frame_id_is_next = 0;
334 frame_obj->gdbarch = get_frame_arch (frame);
336 if (except.reason < 0)
338 Py_DECREF (frame_obj);
339 gdbpy_convert_exception (except);
342 return (PyObject *) frame_obj;
345 /* Implementation of gdb.Frame.older (self) -> gdb.Frame.
346 Returns the frame immediately older (outer) to this frame, or None if
350 frapy_older (PyObject *self, PyObject *args)
352 struct frame_info *frame, *prev = NULL;
353 volatile struct gdb_exception except;
354 PyObject *prev_obj = NULL; /* Initialize to appease gcc warning. */
356 TRY_CATCH (except, RETURN_MASK_ALL)
358 FRAPY_REQUIRE_VALID (self, frame);
360 prev = get_prev_frame (frame);
362 GDB_PY_HANDLE_EXCEPTION (except);
365 prev_obj = (PyObject *) frame_info_to_frame_object (prev);
375 /* Implementation of gdb.Frame.newer (self) -> gdb.Frame.
376 Returns the frame immediately newer (inner) to this frame, or None if
380 frapy_newer (PyObject *self, PyObject *args)
382 struct frame_info *frame, *next = NULL;
383 volatile struct gdb_exception except;
384 PyObject *next_obj = NULL; /* Initialize to appease gcc warning. */
386 TRY_CATCH (except, RETURN_MASK_ALL)
388 FRAPY_REQUIRE_VALID (self, frame);
390 next = get_next_frame (frame);
392 GDB_PY_HANDLE_EXCEPTION (except);
395 next_obj = (PyObject *) frame_info_to_frame_object (next);
405 /* Implementation of gdb.Frame.find_sal (self) -> gdb.Symtab_and_line.
406 Returns the frame's symtab and line. */
409 frapy_find_sal (PyObject *self, PyObject *args)
411 struct frame_info *frame;
412 struct symtab_and_line sal;
413 volatile struct gdb_exception except;
414 PyObject *sal_obj = NULL; /* Initialize to appease gcc warning. */
416 TRY_CATCH (except, RETURN_MASK_ALL)
418 FRAPY_REQUIRE_VALID (self, frame);
420 find_frame_sal (frame, &sal);
421 sal_obj = symtab_and_line_to_sal_object (sal);
423 GDB_PY_HANDLE_EXCEPTION (except);
428 /* Implementation of gdb.Frame.read_var_value (self, variable,
429 [block]) -> gdb.Value. If the optional block argument is provided
430 start the search from that block, otherwise search from the frame's
431 current block (determined by examining the resume address of the
432 frame). The variable argument must be a string or an instance of a
433 gdb.Symbol. The block argument must be an instance of gdb.Block. Returns
434 NULL on error, with a python exception set. */
436 frapy_read_var (PyObject *self, PyObject *args)
438 struct frame_info *frame;
439 PyObject *sym_obj, *block_obj = NULL;
440 struct symbol *var = NULL; /* gcc-4.3.2 false warning. */
441 struct value *val = NULL;
442 volatile struct gdb_exception except;
444 if (!PyArg_ParseTuple (args, "O|O", &sym_obj, &block_obj))
447 if (PyObject_TypeCheck (sym_obj, &symbol_object_type))
448 var = symbol_object_to_symbol (sym_obj);
449 else if (gdbpy_is_string (sym_obj))
452 const struct block *block = NULL;
453 struct cleanup *cleanup;
454 volatile struct gdb_exception except;
456 var_name = python_string_to_target_string (sym_obj);
459 cleanup = make_cleanup (xfree, var_name);
463 block = block_object_to_block (block_obj);
466 PyErr_SetString (PyExc_RuntimeError,
467 _("Second argument must be block."));
468 do_cleanups (cleanup);
473 TRY_CATCH (except, RETURN_MASK_ALL)
475 FRAPY_REQUIRE_VALID (self, frame);
478 block = get_frame_block (frame, NULL);
479 var = lookup_symbol (var_name, block, VAR_DOMAIN, NULL);
481 if (except.reason < 0)
483 do_cleanups (cleanup);
484 gdbpy_convert_exception (except);
490 PyErr_Format (PyExc_ValueError,
491 _("Variable '%s' not found."), var_name);
492 do_cleanups (cleanup);
497 do_cleanups (cleanup);
501 PyErr_SetString (PyExc_TypeError,
502 _("Argument must be a symbol or string."));
506 TRY_CATCH (except, RETURN_MASK_ALL)
508 FRAPY_REQUIRE_VALID (self, frame);
510 val = read_var_value (var, frame);
512 GDB_PY_HANDLE_EXCEPTION (except);
514 return value_to_value_object (val);
517 /* Select this frame. */
520 frapy_select (PyObject *self, PyObject *args)
522 struct frame_info *fi;
523 volatile struct gdb_exception except;
525 TRY_CATCH (except, RETURN_MASK_ALL)
527 FRAPY_REQUIRE_VALID (self, fi);
531 GDB_PY_HANDLE_EXCEPTION (except);
536 /* Implementation of gdb.newest_frame () -> gdb.Frame.
537 Returns the newest frame object. */
540 gdbpy_newest_frame (PyObject *self, PyObject *args)
542 struct frame_info *frame = NULL;
543 volatile struct gdb_exception except;
545 TRY_CATCH (except, RETURN_MASK_ALL)
547 frame = get_current_frame ();
549 GDB_PY_HANDLE_EXCEPTION (except);
551 return frame_info_to_frame_object (frame);
554 /* Implementation of gdb.selected_frame () -> gdb.Frame.
555 Returns the selected frame object. */
558 gdbpy_selected_frame (PyObject *self, PyObject *args)
560 struct frame_info *frame = NULL;
561 volatile struct gdb_exception except;
563 TRY_CATCH (except, RETURN_MASK_ALL)
565 frame = get_selected_frame ("No frame is currently selected.");
567 GDB_PY_HANDLE_EXCEPTION (except);
569 return frame_info_to_frame_object (frame);
572 /* Implementation of gdb.stop_reason_string (Integer) -> String.
573 Return a string explaining the unwind stop reason. */
576 gdbpy_frame_stop_reason_string (PyObject *self, PyObject *args)
581 if (!PyArg_ParseTuple (args, "i", &reason))
584 if (reason < UNWIND_FIRST || reason > UNWIND_LAST)
586 PyErr_SetString (PyExc_ValueError,
587 _("Invalid frame stop reason."));
591 str = unwind_stop_reason_to_string (reason);
592 return PyUnicode_Decode (str, strlen (str), host_charset (), NULL);
595 /* Implements the equality comparison for Frame objects.
596 All other comparison operators will throw a TypeError Python exception,
597 as they aren't valid for frames. */
600 frapy_richcompare (PyObject *self, PyObject *other, int op)
604 if (!PyObject_TypeCheck (other, &frame_object_type)
605 || (op != Py_EQ && op != Py_NE))
607 Py_INCREF (Py_NotImplemented);
608 return Py_NotImplemented;
611 if (frame_id_eq (((frame_object *) self)->frame_id,
612 ((frame_object *) other)->frame_id))
622 /* Sets up the Frame API in the gdb module. */
625 gdbpy_initialize_frames (void)
627 frame_object_type.tp_new = PyType_GenericNew;
628 if (PyType_Ready (&frame_object_type) < 0)
631 /* Note: These would probably be best exposed as class attributes of
632 Frame, but I don't know how to do it except by messing with the
633 type's dictionary. That seems too messy. */
634 if (PyModule_AddIntConstant (gdb_module, "NORMAL_FRAME", NORMAL_FRAME) < 0
635 || PyModule_AddIntConstant (gdb_module, "DUMMY_FRAME", DUMMY_FRAME) < 0
636 || PyModule_AddIntConstant (gdb_module, "INLINE_FRAME", INLINE_FRAME) < 0
637 || PyModule_AddIntConstant (gdb_module, "TAILCALL_FRAME",
639 || PyModule_AddIntConstant (gdb_module, "SIGTRAMP_FRAME",
641 || PyModule_AddIntConstant (gdb_module, "ARCH_FRAME", ARCH_FRAME) < 0
642 || PyModule_AddIntConstant (gdb_module, "SENTINEL_FRAME",
646 #define SET(name, description) \
647 if (PyModule_AddIntConstant (gdb_module, "FRAME_"#name, name) < 0) \
649 #include "unwind_stop_reasons.def"
652 return gdb_pymodule_addobject (gdb_module, "Frame",
653 (PyObject *) &frame_object_type);
658 static PyMethodDef frame_object_methods[] = {
659 { "is_valid", frapy_is_valid, METH_NOARGS,
660 "is_valid () -> Boolean.\n\
661 Return true if this frame is valid, false if not." },
662 { "name", frapy_name, METH_NOARGS,
663 "name () -> String.\n\
664 Return the function name of the frame, or None if it can't be determined." },
665 { "type", frapy_type, METH_NOARGS,
666 "type () -> Integer.\n\
667 Return the type of the frame." },
668 { "architecture", frapy_arch, METH_NOARGS,
669 "architecture () -> gdb.Architecture.\n\
670 Return the architecture of the frame." },
671 { "unwind_stop_reason", frapy_unwind_stop_reason, METH_NOARGS,
672 "unwind_stop_reason () -> Integer.\n\
673 Return the reason why it's not possible to find frames older than this." },
674 { "pc", frapy_pc, METH_NOARGS,
676 Return the frame's resume address." },
677 { "block", frapy_block, METH_NOARGS,
678 "block () -> gdb.Block.\n\
679 Return the frame's code block." },
680 { "function", frapy_function, METH_NOARGS,
681 "function () -> gdb.Symbol.\n\
682 Returns the symbol for the function corresponding to this frame." },
683 { "older", frapy_older, METH_NOARGS,
684 "older () -> gdb.Frame.\n\
685 Return the frame that called this frame." },
686 { "newer", frapy_newer, METH_NOARGS,
687 "newer () -> gdb.Frame.\n\
688 Return the frame called by this frame." },
689 { "find_sal", frapy_find_sal, METH_NOARGS,
690 "find_sal () -> gdb.Symtab_and_line.\n\
691 Return the frame's symtab and line." },
692 { "read_var", frapy_read_var, METH_VARARGS,
693 "read_var (variable) -> gdb.Value.\n\
694 Return the value of the variable in this frame." },
695 { "select", frapy_select, METH_NOARGS,
696 "Select this frame as the user's current frame." },
697 {NULL} /* Sentinel */
700 PyTypeObject frame_object_type = {
701 PyVarObject_HEAD_INIT (NULL, 0)
702 "gdb.Frame", /* tp_name */
703 sizeof (frame_object), /* tp_basicsize */
711 0, /* tp_as_number */
712 0, /* tp_as_sequence */
713 0, /* tp_as_mapping */
716 frapy_str, /* tp_str */
719 0, /* tp_as_buffer */
720 Py_TPFLAGS_DEFAULT, /* tp_flags */
721 "GDB frame object", /* tp_doc */
724 frapy_richcompare, /* tp_richcompare */
725 0, /* tp_weaklistoffset */
728 frame_object_methods, /* tp_methods */
733 0, /* tp_descr_get */
734 0, /* tp_descr_set */
735 0, /* tp_dictoffset */