1 /* Python interface to symbols. 2 3 Copyright (C) 2008-2019 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 const char *keywords[] = { "name", "block", "domain", NULL }; 376 struct symbol *symbol = NULL; 377 PyObject *block_obj = NULL, *sym_obj, *bool_obj; 378 const struct block *block = NULL; 379 380 if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|O!i", keywords, &name, 381 &block_object_type, &block_obj, 382 &domain)) 383 return NULL; 384 385 if (block_obj) 386 block = block_object_to_block (block_obj); 387 else 388 { 389 struct frame_info *selected_frame; 390 391 TRY 392 { 393 selected_frame = get_selected_frame (_("No frame selected.")); 394 block = get_frame_block (selected_frame, NULL); 395 } 396 CATCH (except, RETURN_MASK_ALL) 397 { 398 GDB_PY_HANDLE_EXCEPTION (except); 399 } 400 END_CATCH 401 } 402 403 TRY 404 { 405 symbol = lookup_symbol (name, block, (domain_enum) domain, 406 &is_a_field_of_this).symbol; 407 } 408 CATCH (except, RETURN_MASK_ALL) 409 { 410 GDB_PY_HANDLE_EXCEPTION (except); 411 } 412 END_CATCH 413 414 gdbpy_ref<> ret_tuple (PyTuple_New (2)); 415 if (ret_tuple == NULL) 416 return NULL; 417 418 if (symbol) 419 { 420 sym_obj = symbol_to_symbol_object (symbol); 421 if (!sym_obj) 422 return NULL; 423 } 424 else 425 { 426 sym_obj = Py_None; 427 Py_INCREF (Py_None); 428 } 429 PyTuple_SET_ITEM (ret_tuple.get (), 0, sym_obj); 430 431 bool_obj = (is_a_field_of_this.type != NULL) ? Py_True : Py_False; 432 Py_INCREF (bool_obj); 433 PyTuple_SET_ITEM (ret_tuple.get (), 1, bool_obj); 434 435 return ret_tuple.release (); 436 } 437 438 /* Implementation of 439 gdb.lookup_global_symbol (name [, domain]) -> symbol or None. */ 440 441 PyObject * 442 gdbpy_lookup_global_symbol (PyObject *self, PyObject *args, PyObject *kw) 443 { 444 int domain = VAR_DOMAIN; 445 const char *name; 446 static const char *keywords[] = { "name", "domain", NULL }; 447 struct symbol *symbol = NULL; 448 PyObject *sym_obj; 449 450 if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &name, 451 &domain)) 452 return NULL; 453 454 TRY 455 { 456 symbol = lookup_global_symbol (name, NULL, (domain_enum) domain).symbol; 457 } 458 CATCH (except, RETURN_MASK_ALL) 459 { 460 GDB_PY_HANDLE_EXCEPTION (except); 461 } 462 END_CATCH 463 464 if (symbol) 465 { 466 sym_obj = symbol_to_symbol_object (symbol); 467 if (!sym_obj) 468 return NULL; 469 } 470 else 471 { 472 sym_obj = Py_None; 473 Py_INCREF (Py_None); 474 } 475 476 return sym_obj; 477 } 478 479 /* This function is called when an objfile is about to be freed. 480 Invalidate the symbol as further actions on the symbol would result 481 in bad data. All access to obj->symbol should be gated by 482 SYMPY_REQUIRE_VALID which will raise an exception on invalid 483 symbols. */ 484 static void 485 del_objfile_symbols (struct objfile *objfile, void *datum) 486 { 487 symbol_object *obj = (symbol_object *) datum; 488 while (obj) 489 { 490 symbol_object *next = obj->next; 491 492 obj->symbol = NULL; 493 obj->next = NULL; 494 obj->prev = NULL; 495 496 obj = next; 497 } 498 } 499 500 int 501 gdbpy_initialize_symbols (void) 502 { 503 if (PyType_Ready (&symbol_object_type) < 0) 504 return -1; 505 506 /* Register an objfile "free" callback so we can properly 507 invalidate symbol when an object file that is about to be 508 deleted. */ 509 sympy_objfile_data_key 510 = register_objfile_data_with_cleanup (NULL, del_objfile_symbols); 511 512 if (PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNDEF", LOC_UNDEF) < 0 513 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST", 514 LOC_CONST) < 0 515 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_STATIC", 516 LOC_STATIC) < 0 517 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGISTER", 518 LOC_REGISTER) < 0 519 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_ARG", 520 LOC_ARG) < 0 521 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REF_ARG", 522 LOC_REF_ARG) < 0 523 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LOCAL", 524 LOC_LOCAL) < 0 525 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_TYPEDEF", 526 LOC_TYPEDEF) < 0 527 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LABEL", 528 LOC_LABEL) < 0 529 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_BLOCK", 530 LOC_BLOCK) < 0 531 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST_BYTES", 532 LOC_CONST_BYTES) < 0 533 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNRESOLVED", 534 LOC_UNRESOLVED) < 0 535 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_OPTIMIZED_OUT", 536 LOC_OPTIMIZED_OUT) < 0 537 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMPUTED", 538 LOC_COMPUTED) < 0 539 || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMMON_BLOCK", 540 LOC_COMMON_BLOCK) < 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_MODULE_DOMAIN", 550 MODULE_DOMAIN) < 0 551 || PyModule_AddIntConstant (gdb_module, "SYMBOL_COMMON_BLOCK_DOMAIN", 552 COMMON_BLOCK_DOMAIN) < 0) 553 return -1; 554 555 /* These remain defined for compatibility, but as they were never 556 correct, they are no longer documented. Eventually we can remove 557 them. These exist because at one time, enum search_domain and 558 enum domain_enum_tag were combined -- but different values were 559 used differently. Here we try to give them values that will make 560 sense if they are passed to gdb.lookup_symbol. */ 561 if (PyModule_AddIntConstant (gdb_module, "SYMBOL_VARIABLES_DOMAIN", 562 VAR_DOMAIN) < 0 563 || PyModule_AddIntConstant (gdb_module, "SYMBOL_FUNCTIONS_DOMAIN", 564 VAR_DOMAIN) < 0 565 || PyModule_AddIntConstant (gdb_module, "SYMBOL_TYPES_DOMAIN", 566 VAR_DOMAIN) < 0) 567 return -1; 568 569 return gdb_pymodule_addobject (gdb_module, "Symbol", 570 (PyObject *) &symbol_object_type); 571 } 572 573 574 575 static gdb_PyGetSetDef symbol_object_getset[] = { 576 { "type", sympy_get_type, NULL, 577 "Type of the symbol.", NULL }, 578 { "symtab", sympy_get_symtab, NULL, 579 "Symbol table in which the symbol appears.", NULL }, 580 { "name", sympy_get_name, NULL, 581 "Name of the symbol, as it appears in the source code.", NULL }, 582 { "linkage_name", sympy_get_linkage_name, NULL, 583 "Name of the symbol, as used by the linker (i.e., may be mangled).", 584 NULL }, 585 { "print_name", sympy_get_print_name, NULL, 586 "Name of the symbol in a form suitable for output.\n\ 587 This is either name or linkage_name, depending on whether the user asked GDB\n\ 588 to display demangled or mangled names.", NULL }, 589 { "addr_class", sympy_get_addr_class, NULL, "Address class of the symbol." }, 590 { "is_argument", sympy_is_argument, NULL, 591 "True if the symbol is an argument of a function." }, 592 { "is_constant", sympy_is_constant, NULL, 593 "True if the symbol is a constant." }, 594 { "is_function", sympy_is_function, NULL, 595 "True if the symbol is a function or method." }, 596 { "is_variable", sympy_is_variable, NULL, 597 "True if the symbol is a variable." }, 598 { "needs_frame", sympy_needs_frame, NULL, 599 "True if the symbol requires a frame for evaluation." }, 600 { "line", sympy_line, NULL, 601 "The source line number at which the symbol was defined." }, 602 { NULL } /* Sentinel */ 603 }; 604 605 static PyMethodDef symbol_object_methods[] = { 606 { "is_valid", sympy_is_valid, METH_NOARGS, 607 "is_valid () -> Boolean.\n\ 608 Return true if this symbol is valid, false if not." }, 609 { "value", sympy_value, METH_VARARGS, 610 "value ([frame]) -> gdb.Value\n\ 611 Return the value of the symbol." }, 612 {NULL} /* Sentinel */ 613 }; 614 615 PyTypeObject symbol_object_type = { 616 PyVarObject_HEAD_INIT (NULL, 0) 617 "gdb.Symbol", /*tp_name*/ 618 sizeof (symbol_object), /*tp_basicsize*/ 619 0, /*tp_itemsize*/ 620 sympy_dealloc, /*tp_dealloc*/ 621 0, /*tp_print*/ 622 0, /*tp_getattr*/ 623 0, /*tp_setattr*/ 624 0, /*tp_compare*/ 625 0, /*tp_repr*/ 626 0, /*tp_as_number*/ 627 0, /*tp_as_sequence*/ 628 0, /*tp_as_mapping*/ 629 0, /*tp_hash */ 630 0, /*tp_call*/ 631 sympy_str, /*tp_str*/ 632 0, /*tp_getattro*/ 633 0, /*tp_setattro*/ 634 0, /*tp_as_buffer*/ 635 Py_TPFLAGS_DEFAULT, /*tp_flags*/ 636 "GDB symbol object", /*tp_doc */ 637 0, /*tp_traverse */ 638 0, /*tp_clear */ 639 0, /*tp_richcompare */ 640 0, /*tp_weaklistoffset */ 641 0, /*tp_iter */ 642 0, /*tp_iternext */ 643 symbol_object_methods, /*tp_methods */ 644 0, /*tp_members */ 645 symbol_object_getset /*tp_getset */ 646 }; 647