1 /* Python interface to symbols. 2 3 Copyright (C) 2008-2016 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 "block.h" 22 #include "frame.h" 23 #include "symtab.h" 24 #include "python-internal.h" 25 #include "objfiles.h" 26 27 typedef struct sympy_symbol_object { 28 PyObject_HEAD 29 /* The GDB symbol structure this object is wrapping. */ 30 struct symbol *symbol; 31 /* A symbol object is associated with an objfile, so keep track with 32 doubly-linked list, rooted in the objfile. This lets us 33 invalidate the underlying struct symbol when the objfile is 34 deleted. */ 35 struct sympy_symbol_object *prev; 36 struct sympy_symbol_object *next; 37 } symbol_object; 38 39 /* Require a valid symbol. All access to symbol_object->symbol should be 40 gated by this call. */ 41 #define SYMPY_REQUIRE_VALID(symbol_obj, symbol) \ 42 do { \ 43 symbol = symbol_object_to_symbol (symbol_obj); \ 44 if (symbol == NULL) \ 45 { \ 46 PyErr_SetString (PyExc_RuntimeError, \ 47 _("Symbol is invalid.")); \ 48 return NULL; \ 49 } \ 50 } while (0) 51 52 static const struct objfile_data *sympy_objfile_data_key; 53 54 static PyObject * 55 sympy_str (PyObject *self) 56 { 57 PyObject *result; 58 struct symbol *symbol = NULL; 59 60 SYMPY_REQUIRE_VALID (self, symbol); 61 62 result = PyString_FromString (SYMBOL_PRINT_NAME (symbol)); 63 64 return result; 65 } 66 67 static PyObject * 68 sympy_get_type (PyObject *self, void *closure) 69 { 70 struct symbol *symbol = NULL; 71 72 SYMPY_REQUIRE_VALID (self, symbol); 73 74 if (SYMBOL_TYPE (symbol) == NULL) 75 { 76 Py_INCREF (Py_None); 77 return Py_None; 78 } 79 80 return type_to_type_object (SYMBOL_TYPE (symbol)); 81 } 82 83 static PyObject * 84 sympy_get_symtab (PyObject *self, void *closure) 85 { 86 struct symbol *symbol = NULL; 87 88 SYMPY_REQUIRE_VALID (self, symbol); 89 90 if (!SYMBOL_OBJFILE_OWNED (symbol)) 91 Py_RETURN_NONE; 92 93 return symtab_to_symtab_object (symbol_symtab (symbol)); 94 } 95 96 static PyObject * 97 sympy_get_name (PyObject *self, void *closure) 98 { 99 struct symbol *symbol = NULL; 100 101 SYMPY_REQUIRE_VALID (self, symbol); 102 103 return PyString_FromString (SYMBOL_NATURAL_NAME (symbol)); 104 } 105 106 static PyObject * 107 sympy_get_linkage_name (PyObject *self, void *closure) 108 { 109 struct symbol *symbol = NULL; 110 111 SYMPY_REQUIRE_VALID (self, symbol); 112 113 return PyString_FromString (SYMBOL_LINKAGE_NAME (symbol)); 114 } 115 116 static PyObject * 117 sympy_get_print_name (PyObject *self, void *closure) 118 { 119 struct symbol *symbol = NULL; 120 121 SYMPY_REQUIRE_VALID (self, symbol); 122 123 return sympy_str (self); 124 } 125 126 static PyObject * 127 sympy_get_addr_class (PyObject *self, void *closure) 128 { 129 struct symbol *symbol = NULL; 130 131 SYMPY_REQUIRE_VALID (self, symbol); 132 133 return PyInt_FromLong (SYMBOL_CLASS (symbol)); 134 } 135 136 static PyObject * 137 sympy_is_argument (PyObject *self, void *closure) 138 { 139 struct symbol *symbol = NULL; 140 141 SYMPY_REQUIRE_VALID (self, symbol); 142 143 return PyBool_FromLong (SYMBOL_IS_ARGUMENT (symbol)); 144 } 145 146 static PyObject * 147 sympy_is_constant (PyObject *self, void *closure) 148 { 149 struct symbol *symbol = NULL; 150 enum address_class theclass; 151 152 SYMPY_REQUIRE_VALID (self, symbol); 153 154 theclass = SYMBOL_CLASS (symbol); 155 156 return PyBool_FromLong (theclass == LOC_CONST || theclass == LOC_CONST_BYTES); 157 } 158 159 static PyObject * 160 sympy_is_function (PyObject *self, void *closure) 161 { 162 struct symbol *symbol = NULL; 163 enum address_class theclass; 164 165 SYMPY_REQUIRE_VALID (self, symbol); 166 167 theclass = SYMBOL_CLASS (symbol); 168 169 return PyBool_FromLong (theclass == LOC_BLOCK); 170 } 171 172 static PyObject * 173 sympy_is_variable (PyObject *self, void *closure) 174 { 175 struct symbol *symbol = NULL; 176 enum address_class theclass; 177 178 SYMPY_REQUIRE_VALID (self, symbol); 179 180 theclass = SYMBOL_CLASS (symbol); 181 182 return PyBool_FromLong (!SYMBOL_IS_ARGUMENT (symbol) 183 && (theclass == LOC_LOCAL || theclass == LOC_REGISTER 184 || theclass == LOC_STATIC || theclass == LOC_COMPUTED 185 || theclass == LOC_OPTIMIZED_OUT)); 186 } 187 188 /* Implementation of gdb.Symbol.needs_frame -> Boolean. 189 Returns true iff the symbol needs a frame for evaluation. */ 190 191 static PyObject * 192 sympy_needs_frame (PyObject *self, void *closure) 193 { 194 struct symbol *symbol = NULL; 195 int result = 0; 196 197 SYMPY_REQUIRE_VALID (self, symbol); 198 199 TRY 200 { 201 result = symbol_read_needs_frame (symbol); 202 } 203 CATCH (except, RETURN_MASK_ALL) 204 { 205 GDB_PY_HANDLE_EXCEPTION (except); 206 } 207 END_CATCH 208 209 if (result) 210 Py_RETURN_TRUE; 211 Py_RETURN_FALSE; 212 } 213 214 /* Implementation of gdb.Symbol.line -> int. 215 Returns the line number at which the symbol was defined. */ 216 217 static PyObject * 218 sympy_line (PyObject *self, void *closure) 219 { 220 struct symbol *symbol = NULL; 221 222 SYMPY_REQUIRE_VALID (self, symbol); 223 224 return PyInt_FromLong (SYMBOL_LINE (symbol)); 225 } 226 227 /* Implementation of gdb.Symbol.is_valid (self) -> Boolean. 228 Returns True if this Symbol still exists in GDB. */ 229 230 static PyObject * 231 sympy_is_valid (PyObject *self, PyObject *args) 232 { 233 struct symbol *symbol = NULL; 234 235 symbol = symbol_object_to_symbol (self); 236 if (symbol == NULL) 237 Py_RETURN_FALSE; 238 239 Py_RETURN_TRUE; 240 } 241 242 /* Implementation of gdb.Symbol.value (self[, frame]) -> gdb.Value. Returns 243 the value of the symbol, or an error in various circumstances. */ 244 245 static PyObject * 246 sympy_value (PyObject *self, PyObject *args) 247 { 248 struct symbol *symbol = NULL; 249 struct frame_info *frame_info = NULL; 250 PyObject *frame_obj = NULL; 251 struct value *value = NULL; 252 253 if (!PyArg_ParseTuple (args, "|O", &frame_obj)) 254 return NULL; 255 256 if (frame_obj != NULL && !PyObject_TypeCheck (frame_obj, &frame_object_type)) 257 { 258 PyErr_SetString (PyExc_TypeError, "argument is not a frame"); 259 return NULL; 260 } 261 262 SYMPY_REQUIRE_VALID (self, symbol); 263 if (SYMBOL_CLASS (symbol) == LOC_TYPEDEF) 264 { 265 PyErr_SetString (PyExc_TypeError, "cannot get the value of a typedef"); 266 return NULL; 267 } 268 269 TRY 270 { 271 if (frame_obj != NULL) 272 { 273 frame_info = frame_object_to_frame_info (frame_obj); 274 if (frame_info == NULL) 275 error (_("invalid frame")); 276 } 277 278 if (symbol_read_needs_frame (symbol) && frame_info == NULL) 279 error (_("symbol requires a frame to compute its value")); 280 281 /* TODO: currently, we have no way to recover the block in which SYMBOL 282 was found, so we have no block to pass to read_var_value. This will 283 yield an incorrect value when symbol is not local to FRAME_INFO (this 284 can happen with nested functions). */ 285 value = read_var_value (symbol, NULL, frame_info); 286 } 287 CATCH (except, RETURN_MASK_ALL) 288 { 289 GDB_PY_HANDLE_EXCEPTION (except); 290 } 291 END_CATCH 292 293 return value_to_value_object (value); 294 } 295 296 /* Given a symbol, and a symbol_object that has previously been 297 allocated and initialized, populate the symbol_object with the 298 struct symbol data. Also, register the symbol_object life-cycle 299 with the life-cycle of the object file associated with this 300 symbol, if needed. */ 301 static void 302 set_symbol (symbol_object *obj, struct symbol *symbol) 303 { 304 obj->symbol = symbol; 305 obj->prev = NULL; 306 if (SYMBOL_OBJFILE_OWNED (symbol) 307 && symbol_symtab (symbol) != NULL) 308 { 309 struct objfile *objfile = symbol_objfile (symbol); 310 311 obj->next = ((struct sympy_symbol_object *) 312 objfile_data (objfile, sympy_objfile_data_key)); 313 if (obj->next) 314 obj->next->prev = obj; 315 set_objfile_data (objfile, sympy_objfile_data_key, obj); 316 } 317 else 318 obj->next = NULL; 319 } 320 321 /* Create a new symbol object (gdb.Symbol) that encapsulates the struct 322 symbol object from GDB. */ 323 PyObject * 324 symbol_to_symbol_object (struct symbol *sym) 325 { 326 symbol_object *sym_obj; 327 328 sym_obj = PyObject_New (symbol_object, &symbol_object_type); 329 if (sym_obj) 330 set_symbol (sym_obj, sym); 331 332 return (PyObject *) sym_obj; 333 } 334 335 /* Return the symbol that is wrapped by this symbol object. */ 336 struct symbol * 337 symbol_object_to_symbol (PyObject *obj) 338 { 339 if (! PyObject_TypeCheck (obj, &symbol_object_type)) 340 return NULL; 341 return ((symbol_object *) obj)->symbol; 342 } 343 344 static void 345 sympy_dealloc (PyObject *obj) 346 { 347 symbol_object *sym_obj = (symbol_object *) obj; 348 349 if (sym_obj->prev) 350 sym_obj->prev->next = sym_obj->next; 351 else if (sym_obj->symbol != NULL 352 && SYMBOL_OBJFILE_OWNED (sym_obj->symbol) 353 && symbol_symtab (sym_obj->symbol) != NULL) 354 { 355 set_objfile_data (symbol_objfile (sym_obj->symbol), 356 sympy_objfile_data_key, sym_obj->next); 357 } 358 if (sym_obj->next) 359 sym_obj->next->prev = sym_obj->prev; 360 sym_obj->symbol = NULL; 361 } 362 363 /* Implementation of 364 gdb.lookup_symbol (name [, block] [, domain]) -> (symbol, is_field_of_this) 365 A tuple with 2 elements is always returned. The first is the symbol 366 object or None, the second is a boolean with the value of 367 is_a_field_of_this (see comment in lookup_symbol_in_language). */ 368 369 PyObject * 370 gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw) 371 { 372 int domain = VAR_DOMAIN; 373 struct field_of_this_result is_a_field_of_this; 374 const char *name; 375 static char *keywords[] = { "name", "block", "domain", NULL }; 376 struct symbol *symbol = NULL; 377 PyObject *block_obj = NULL, *ret_tuple, *sym_obj, *bool_obj; 378 const struct block *block = NULL; 379 380 if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!i", keywords, &name, 381 &block_object_type, &block_obj, &domain)) 382 return NULL; 383 384 if (block_obj) 385 block = block_object_to_block (block_obj); 386 else 387 { 388 struct frame_info *selected_frame; 389 390 TRY 391 { 392 selected_frame = get_selected_frame (_("No frame selected.")); 393 block = get_frame_block (selected_frame, NULL); 394 } 395 CATCH (except, RETURN_MASK_ALL) 396 { 397 GDB_PY_HANDLE_EXCEPTION (except); 398 } 399 END_CATCH 400 } 401 402 TRY 403 { 404 symbol = lookup_symbol (name, block, (domain_enum) domain, 405 &is_a_field_of_this).symbol; 406 } 407 CATCH (except, RETURN_MASK_ALL) 408 { 409 GDB_PY_HANDLE_EXCEPTION (except); 410 } 411 END_CATCH 412 413 ret_tuple = PyTuple_New (2); 414 if (!ret_tuple) 415 return NULL; 416 417 if (symbol) 418 { 419 sym_obj = symbol_to_symbol_object (symbol); 420 if (!sym_obj) 421 { 422 Py_DECREF (ret_tuple); 423 return NULL; 424 } 425 } 426 else 427 { 428 sym_obj = Py_None; 429 Py_INCREF (Py_None); 430 } 431 PyTuple_SET_ITEM (ret_tuple, 0, sym_obj); 432 433 bool_obj = (is_a_field_of_this.type != NULL) ? Py_True : Py_False; 434 Py_INCREF (bool_obj); 435 PyTuple_SET_ITEM (ret_tuple, 1, bool_obj); 436 437 return ret_tuple; 438 } 439 440 /* Implementation of 441 gdb.lookup_global_symbol (name [, domain]) -> symbol or None. */ 442 443 PyObject * 444 gdbpy_lookup_global_symbol (PyObject *self, PyObject *args, PyObject *kw) 445 { 446 int domain = VAR_DOMAIN; 447 const char *name; 448 static char *keywords[] = { "name", "domain", NULL }; 449 struct symbol *symbol = NULL; 450 PyObject *sym_obj; 451 452 if (! PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &name, 453 &domain)) 454 return NULL; 455 456 TRY 457 { 458 symbol = lookup_global_symbol (name, NULL, (domain_enum) domain).symbol; 459 } 460 CATCH (except, RETURN_MASK_ALL) 461 { 462 GDB_PY_HANDLE_EXCEPTION (except); 463 } 464 END_CATCH 465 466 if (symbol) 467 { 468 sym_obj = symbol_to_symbol_object (symbol); 469 if (!sym_obj) 470 return NULL; 471 } 472 else 473 { 474 sym_obj = Py_None; 475 Py_INCREF (Py_None); 476 } 477 478 return sym_obj; 479 } 480 481 /* This function is called when an objfile is about to be freed. 482 Invalidate the symbol as further actions on the symbol would result 483 in bad data. All access to obj->symbol should be gated by 484 SYMPY_REQUIRE_VALID which will raise an exception on invalid 485 symbols. */ 486 static void 487 del_objfile_symbols (struct objfile *objfile, void *datum) 488 { 489 symbol_object *obj = (symbol_object *) datum; 490 while (obj) 491 { 492 symbol_object *next = obj->next; 493 494 obj->symbol = NULL; 495 obj->next = NULL; 496 obj->prev = NULL; 497 498 obj = next; 499 } 500 } 501 502 int 503 gdbpy_initialize_symbols (void) 504 { 505 if (PyType_Ready (&symbol_object_type) < 0) 506 return -1; 507 508 /* Register an objfile "free" callback so we can properly 509 invalidate symbol when an object file that is about to be 510 deleted. */ 511 sympy_objfile_data_key 512 = register_objfile_data_with_cleanup (NULL, del_objfile_symbols); 513 514 if (PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNDEF", LOC_UNDEF) < 0 515 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST", 516 LOC_CONST) < 0 517 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_STATIC", 518 LOC_STATIC) < 0 519 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGISTER", 520 LOC_REGISTER) < 0 521 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_ARG", 522 LOC_ARG) < 0 523 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REF_ARG", 524 LOC_REF_ARG) < 0 525 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LOCAL", 526 LOC_LOCAL) < 0 527 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_TYPEDEF", 528 LOC_TYPEDEF) < 0 529 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LABEL", 530 LOC_LABEL) < 0 531 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_BLOCK", 532 LOC_BLOCK) < 0 533 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST_BYTES", 534 LOC_CONST_BYTES) < 0 535 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNRESOLVED", 536 LOC_UNRESOLVED) < 0 537 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_OPTIMIZED_OUT", 538 LOC_OPTIMIZED_OUT) < 0 539 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMPUTED", 540 LOC_COMPUTED) < 0 541 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGPARM_ADDR", 542 LOC_REGPARM_ADDR) < 0 543 || PyModule_AddIntConstant (gdb_module, "SYMBOL_UNDEF_DOMAIN", 544 UNDEF_DOMAIN) < 0 545 || PyModule_AddIntConstant (gdb_module, "SYMBOL_VAR_DOMAIN", 546 VAR_DOMAIN) < 0 547 || PyModule_AddIntConstant (gdb_module, "SYMBOL_STRUCT_DOMAIN", 548 STRUCT_DOMAIN) < 0 549 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LABEL_DOMAIN", 550 LABEL_DOMAIN) < 0 551 || PyModule_AddIntConstant (gdb_module, "SYMBOL_VARIABLES_DOMAIN", 552 VARIABLES_DOMAIN) < 0 553 || PyModule_AddIntConstant (gdb_module, "SYMBOL_FUNCTIONS_DOMAIN", 554 FUNCTIONS_DOMAIN) < 0 555 || PyModule_AddIntConstant (gdb_module, "SYMBOL_TYPES_DOMAIN", 556 TYPES_DOMAIN) < 0) 557 return -1; 558 559 return gdb_pymodule_addobject (gdb_module, "Symbol", 560 (PyObject *) &symbol_object_type); 561 } 562 563 564 565 static PyGetSetDef symbol_object_getset[] = { 566 { "type", sympy_get_type, NULL, 567 "Type of the symbol.", NULL }, 568 { "symtab", sympy_get_symtab, NULL, 569 "Symbol table in which the symbol appears.", NULL }, 570 { "name", sympy_get_name, NULL, 571 "Name of the symbol, as it appears in the source code.", NULL }, 572 { "linkage_name", sympy_get_linkage_name, NULL, 573 "Name of the symbol, as used by the linker (i.e., may be mangled).", 574 NULL }, 575 { "print_name", sympy_get_print_name, NULL, 576 "Name of the symbol in a form suitable for output.\n\ 577 This is either name or linkage_name, depending on whether the user asked GDB\n\ 578 to display demangled or mangled names.", NULL }, 579 { "addr_class", sympy_get_addr_class, NULL, "Address class of the symbol." }, 580 { "is_argument", sympy_is_argument, NULL, 581 "True if the symbol is an argument of a function." }, 582 { "is_constant", sympy_is_constant, NULL, 583 "True if the symbol is a constant." }, 584 { "is_function", sympy_is_function, NULL, 585 "True if the symbol is a function or method." }, 586 { "is_variable", sympy_is_variable, NULL, 587 "True if the symbol is a variable." }, 588 { "needs_frame", sympy_needs_frame, NULL, 589 "True if the symbol requires a frame for evaluation." }, 590 { "line", sympy_line, NULL, 591 "The source line number at which the symbol was defined." }, 592 { NULL } /* Sentinel */ 593 }; 594 595 static PyMethodDef symbol_object_methods[] = { 596 { "is_valid", sympy_is_valid, METH_NOARGS, 597 "is_valid () -> Boolean.\n\ 598 Return true if this symbol is valid, false if not." }, 599 { "value", sympy_value, METH_VARARGS, 600 "value ([frame]) -> gdb.Value\n\ 601 Return the value of the symbol." }, 602 {NULL} /* Sentinel */ 603 }; 604 605 PyTypeObject symbol_object_type = { 606 PyVarObject_HEAD_INIT (NULL, 0) 607 "gdb.Symbol", /*tp_name*/ 608 sizeof (symbol_object), /*tp_basicsize*/ 609 0, /*tp_itemsize*/ 610 sympy_dealloc, /*tp_dealloc*/ 611 0, /*tp_print*/ 612 0, /*tp_getattr*/ 613 0, /*tp_setattr*/ 614 0, /*tp_compare*/ 615 0, /*tp_repr*/ 616 0, /*tp_as_number*/ 617 0, /*tp_as_sequence*/ 618 0, /*tp_as_mapping*/ 619 0, /*tp_hash */ 620 0, /*tp_call*/ 621 sympy_str, /*tp_str*/ 622 0, /*tp_getattro*/ 623 0, /*tp_setattro*/ 624 0, /*tp_as_buffer*/ 625 Py_TPFLAGS_DEFAULT, /*tp_flags*/ 626 "GDB symbol object", /*tp_doc */ 627 0, /*tp_traverse */ 628 0, /*tp_clear */ 629 0, /*tp_richcompare */ 630 0, /*tp_weaklistoffset */ 631 0, /*tp_iter */ 632 0, /*tp_iternext */ 633 symbol_object_methods, /*tp_methods */ 634 0, /*tp_members */ 635 symbol_object_getset /*tp_getset */ 636 }; 637