1 /* Python interface to stack frames
3 Copyright (C) 2008-2015 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/>. */
27 #include "python-internal.h"
30 #include "user-regs.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.read_register (self, register) -> gdb.Value.
239 Returns the value of a register in this frame. */
242 frapy_read_register (PyObject *self, PyObject *args)
244 volatile struct gdb_exception except;
245 const char *regnum_str;
246 struct value *val = NULL;
248 if (!PyArg_ParseTuple (args, "s", ®num_str))
251 TRY_CATCH (except, RETURN_MASK_ALL)
253 struct frame_info *frame;
256 FRAPY_REQUIRE_VALID (self, frame);
258 regnum = user_reg_map_name_to_regnum (get_frame_arch (frame),
260 strlen (regnum_str));
262 val = value_of_register (regnum, frame);
265 PyErr_SetString (PyExc_ValueError, _("Unknown register."));
267 GDB_PY_HANDLE_EXCEPTION (except);
269 return val == NULL ? NULL : value_to_value_object (val);
272 /* Implementation of gdb.Frame.block (self) -> gdb.Block.
273 Returns the frame's code block. */
276 frapy_block (PyObject *self, PyObject *args)
278 struct frame_info *frame;
279 const struct block *block = NULL, *fn_block;
280 volatile struct gdb_exception except;
282 TRY_CATCH (except, RETURN_MASK_ALL)
284 FRAPY_REQUIRE_VALID (self, frame);
285 block = get_frame_block (frame, NULL);
287 GDB_PY_HANDLE_EXCEPTION (except);
289 for (fn_block = block;
290 fn_block != NULL && BLOCK_FUNCTION (fn_block) == NULL;
291 fn_block = BLOCK_SUPERBLOCK (fn_block))
294 if (block == NULL || fn_block == NULL || BLOCK_FUNCTION (fn_block) == NULL)
296 PyErr_SetString (PyExc_RuntimeError,
297 _("Cannot locate block for frame."));
303 return block_to_block_object
304 (block, symbol_objfile (BLOCK_FUNCTION (fn_block)));
311 /* Implementation of gdb.Frame.function (self) -> gdb.Symbol.
312 Returns the symbol for the function corresponding to this frame. */
315 frapy_function (PyObject *self, PyObject *args)
317 struct symbol *sym = NULL;
318 struct frame_info *frame;
319 volatile struct gdb_exception except;
321 TRY_CATCH (except, RETURN_MASK_ALL)
323 FRAPY_REQUIRE_VALID (self, frame);
325 sym = find_pc_function (get_frame_address_in_block (frame));
327 GDB_PY_HANDLE_EXCEPTION (except);
330 return symbol_to_symbol_object (sym);
335 /* Convert a frame_info struct to a Python Frame object.
336 Sets a Python exception and returns NULL on error. */
339 frame_info_to_frame_object (struct frame_info *frame)
341 frame_object *frame_obj;
342 volatile struct gdb_exception except;
344 frame_obj = PyObject_New (frame_object, &frame_object_type);
345 if (frame_obj == NULL)
348 TRY_CATCH (except, RETURN_MASK_ALL)
351 /* Try to get the previous frame, to determine if this is the last frame
352 in a corrupt stack. If so, we need to store the frame_id of the next
353 frame and not of this one (which is possibly invalid). */
354 if (get_prev_frame (frame) == NULL
355 && get_frame_unwind_stop_reason (frame) != UNWIND_NO_REASON
356 && get_next_frame (frame) != NULL)
358 frame_obj->frame_id = get_frame_id (get_next_frame (frame));
359 frame_obj->frame_id_is_next = 1;
363 frame_obj->frame_id = get_frame_id (frame);
364 frame_obj->frame_id_is_next = 0;
366 frame_obj->gdbarch = get_frame_arch (frame);
368 if (except.reason < 0)
370 Py_DECREF (frame_obj);
371 gdbpy_convert_exception (except);
374 return (PyObject *) frame_obj;
377 /* Implementation of gdb.Frame.older (self) -> gdb.Frame.
378 Returns the frame immediately older (outer) to this frame, or None if
382 frapy_older (PyObject *self, PyObject *args)
384 struct frame_info *frame, *prev = NULL;
385 volatile struct gdb_exception except;
386 PyObject *prev_obj = NULL; /* Initialize to appease gcc warning. */
388 TRY_CATCH (except, RETURN_MASK_ALL)
390 FRAPY_REQUIRE_VALID (self, frame);
392 prev = get_prev_frame (frame);
394 GDB_PY_HANDLE_EXCEPTION (except);
397 prev_obj = (PyObject *) frame_info_to_frame_object (prev);
407 /* Implementation of gdb.Frame.newer (self) -> gdb.Frame.
408 Returns the frame immediately newer (inner) to this frame, or None if
412 frapy_newer (PyObject *self, PyObject *args)
414 struct frame_info *frame, *next = NULL;
415 volatile struct gdb_exception except;
416 PyObject *next_obj = NULL; /* Initialize to appease gcc warning. */
418 TRY_CATCH (except, RETURN_MASK_ALL)
420 FRAPY_REQUIRE_VALID (self, frame);
422 next = get_next_frame (frame);
424 GDB_PY_HANDLE_EXCEPTION (except);
427 next_obj = (PyObject *) frame_info_to_frame_object (next);
437 /* Implementation of gdb.Frame.find_sal (self) -> gdb.Symtab_and_line.
438 Returns the frame's symtab and line. */
441 frapy_find_sal (PyObject *self, PyObject *args)
443 struct frame_info *frame;
444 struct symtab_and_line sal;
445 volatile struct gdb_exception except;
446 PyObject *sal_obj = NULL; /* Initialize to appease gcc warning. */
448 TRY_CATCH (except, RETURN_MASK_ALL)
450 FRAPY_REQUIRE_VALID (self, frame);
452 find_frame_sal (frame, &sal);
453 sal_obj = symtab_and_line_to_sal_object (sal);
455 GDB_PY_HANDLE_EXCEPTION (except);
460 /* Implementation of gdb.Frame.read_var_value (self, variable,
461 [block]) -> gdb.Value. If the optional block argument is provided
462 start the search from that block, otherwise search from the frame's
463 current block (determined by examining the resume address of the
464 frame). The variable argument must be a string or an instance of a
465 gdb.Symbol. The block argument must be an instance of gdb.Block. Returns
466 NULL on error, with a python exception set. */
468 frapy_read_var (PyObject *self, PyObject *args)
470 struct frame_info *frame;
471 PyObject *sym_obj, *block_obj = NULL;
472 struct symbol *var = NULL; /* gcc-4.3.2 false warning. */
473 struct value *val = NULL;
474 volatile struct gdb_exception except;
476 if (!PyArg_ParseTuple (args, "O|O", &sym_obj, &block_obj))
479 if (PyObject_TypeCheck (sym_obj, &symbol_object_type))
480 var = symbol_object_to_symbol (sym_obj);
481 else if (gdbpy_is_string (sym_obj))
484 const struct block *block = NULL;
485 struct cleanup *cleanup;
486 volatile struct gdb_exception except;
488 var_name = python_string_to_target_string (sym_obj);
491 cleanup = make_cleanup (xfree, var_name);
495 block = block_object_to_block (block_obj);
498 PyErr_SetString (PyExc_RuntimeError,
499 _("Second argument must be block."));
500 do_cleanups (cleanup);
505 TRY_CATCH (except, RETURN_MASK_ALL)
507 FRAPY_REQUIRE_VALID (self, frame);
510 block = get_frame_block (frame, NULL);
511 var = lookup_symbol (var_name, block, VAR_DOMAIN, NULL);
513 if (except.reason < 0)
515 do_cleanups (cleanup);
516 gdbpy_convert_exception (except);
522 PyErr_Format (PyExc_ValueError,
523 _("Variable '%s' not found."), var_name);
524 do_cleanups (cleanup);
529 do_cleanups (cleanup);
533 PyErr_SetString (PyExc_TypeError,
534 _("Argument must be a symbol or string."));
538 TRY_CATCH (except, RETURN_MASK_ALL)
540 FRAPY_REQUIRE_VALID (self, frame);
542 val = read_var_value (var, frame);
544 GDB_PY_HANDLE_EXCEPTION (except);
546 return value_to_value_object (val);
549 /* Select this frame. */
552 frapy_select (PyObject *self, PyObject *args)
554 struct frame_info *fi;
555 volatile struct gdb_exception except;
557 TRY_CATCH (except, RETURN_MASK_ALL)
559 FRAPY_REQUIRE_VALID (self, fi);
563 GDB_PY_HANDLE_EXCEPTION (except);
568 /* Implementation of gdb.newest_frame () -> gdb.Frame.
569 Returns the newest frame object. */
572 gdbpy_newest_frame (PyObject *self, PyObject *args)
574 struct frame_info *frame = NULL;
575 volatile struct gdb_exception except;
577 TRY_CATCH (except, RETURN_MASK_ALL)
579 frame = get_current_frame ();
581 GDB_PY_HANDLE_EXCEPTION (except);
583 return frame_info_to_frame_object (frame);
586 /* Implementation of gdb.selected_frame () -> gdb.Frame.
587 Returns the selected frame object. */
590 gdbpy_selected_frame (PyObject *self, PyObject *args)
592 struct frame_info *frame = NULL;
593 volatile struct gdb_exception except;
595 TRY_CATCH (except, RETURN_MASK_ALL)
597 frame = get_selected_frame ("No frame is currently selected.");
599 GDB_PY_HANDLE_EXCEPTION (except);
601 return frame_info_to_frame_object (frame);
604 /* Implementation of gdb.stop_reason_string (Integer) -> String.
605 Return a string explaining the unwind stop reason. */
608 gdbpy_frame_stop_reason_string (PyObject *self, PyObject *args)
613 if (!PyArg_ParseTuple (args, "i", &reason))
616 if (reason < UNWIND_FIRST || reason > UNWIND_LAST)
618 PyErr_SetString (PyExc_ValueError,
619 _("Invalid frame stop reason."));
623 str = unwind_stop_reason_to_string (reason);
624 return PyUnicode_Decode (str, strlen (str), host_charset (), NULL);
627 /* Implements the equality comparison for Frame objects.
628 All other comparison operators will throw a TypeError Python exception,
629 as they aren't valid for frames. */
632 frapy_richcompare (PyObject *self, PyObject *other, int op)
636 if (!PyObject_TypeCheck (other, &frame_object_type)
637 || (op != Py_EQ && op != Py_NE))
639 Py_INCREF (Py_NotImplemented);
640 return Py_NotImplemented;
643 if (frame_id_eq (((frame_object *) self)->frame_id,
644 ((frame_object *) other)->frame_id))
654 /* Sets up the Frame API in the gdb module. */
657 gdbpy_initialize_frames (void)
659 frame_object_type.tp_new = PyType_GenericNew;
660 if (PyType_Ready (&frame_object_type) < 0)
663 /* Note: These would probably be best exposed as class attributes of
664 Frame, but I don't know how to do it except by messing with the
665 type's dictionary. That seems too messy. */
666 if (PyModule_AddIntConstant (gdb_module, "NORMAL_FRAME", NORMAL_FRAME) < 0
667 || PyModule_AddIntConstant (gdb_module, "DUMMY_FRAME", DUMMY_FRAME) < 0
668 || PyModule_AddIntConstant (gdb_module, "INLINE_FRAME", INLINE_FRAME) < 0
669 || PyModule_AddIntConstant (gdb_module, "TAILCALL_FRAME",
671 || PyModule_AddIntConstant (gdb_module, "SIGTRAMP_FRAME",
673 || PyModule_AddIntConstant (gdb_module, "ARCH_FRAME", ARCH_FRAME) < 0
674 || PyModule_AddIntConstant (gdb_module, "SENTINEL_FRAME",
678 #define SET(name, description) \
679 if (PyModule_AddIntConstant (gdb_module, "FRAME_"#name, name) < 0) \
681 #include "unwind_stop_reasons.def"
684 return gdb_pymodule_addobject (gdb_module, "Frame",
685 (PyObject *) &frame_object_type);
690 static PyMethodDef frame_object_methods[] = {
691 { "is_valid", frapy_is_valid, METH_NOARGS,
692 "is_valid () -> Boolean.\n\
693 Return true if this frame is valid, false if not." },
694 { "name", frapy_name, METH_NOARGS,
695 "name () -> String.\n\
696 Return the function name of the frame, or None if it can't be determined." },
697 { "type", frapy_type, METH_NOARGS,
698 "type () -> Integer.\n\
699 Return the type of the frame." },
700 { "architecture", frapy_arch, METH_NOARGS,
701 "architecture () -> gdb.Architecture.\n\
702 Return the architecture of the frame." },
703 { "unwind_stop_reason", frapy_unwind_stop_reason, METH_NOARGS,
704 "unwind_stop_reason () -> Integer.\n\
705 Return the reason why it's not possible to find frames older than this." },
706 { "pc", frapy_pc, METH_NOARGS,
708 Return the frame's resume address." },
709 { "read_register", frapy_read_register, METH_VARARGS,
710 "read_register (register_name) -> gdb.Value\n\
711 Return the value of the register in the frame." },
712 { "block", frapy_block, METH_NOARGS,
713 "block () -> gdb.Block.\n\
714 Return the frame's code block." },
715 { "function", frapy_function, METH_NOARGS,
716 "function () -> gdb.Symbol.\n\
717 Returns the symbol for the function corresponding to this frame." },
718 { "older", frapy_older, METH_NOARGS,
719 "older () -> gdb.Frame.\n\
720 Return the frame that called this frame." },
721 { "newer", frapy_newer, METH_NOARGS,
722 "newer () -> gdb.Frame.\n\
723 Return the frame called by this frame." },
724 { "find_sal", frapy_find_sal, METH_NOARGS,
725 "find_sal () -> gdb.Symtab_and_line.\n\
726 Return the frame's symtab and line." },
727 { "read_var", frapy_read_var, METH_VARARGS,
728 "read_var (variable) -> gdb.Value.\n\
729 Return the value of the variable in this frame." },
730 { "select", frapy_select, METH_NOARGS,
731 "Select this frame as the user's current frame." },
732 {NULL} /* Sentinel */
735 PyTypeObject frame_object_type = {
736 PyVarObject_HEAD_INIT (NULL, 0)
737 "gdb.Frame", /* tp_name */
738 sizeof (frame_object), /* tp_basicsize */
746 0, /* tp_as_number */
747 0, /* tp_as_sequence */
748 0, /* tp_as_mapping */
751 frapy_str, /* tp_str */
754 0, /* tp_as_buffer */
755 Py_TPFLAGS_DEFAULT, /* tp_flags */
756 "GDB frame object", /* tp_doc */
759 frapy_richcompare, /* tp_richcompare */
760 0, /* tp_weaklistoffset */
763 frame_object_methods, /* tp_methods */
768 0, /* tp_descr_get */
769 0, /* tp_descr_set */
770 0, /* tp_dictoffset */