gdb/python/py-symbol.c

   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 (const gdb_exception &except)
 204     {
 205       GDB_PY_HANDLE_EXCEPTION (except);
 206     }
 207
 208   if (result)
 209     Py_RETURN_TRUE;
 210   Py_RETURN_FALSE;
 211 }
 212
 213 /* Implementation of gdb.Symbol.line -> int.
 214    Returns the line number at which the symbol was defined.  */
 215
 216 static PyObject *
 217 sympy_line (PyObject *self, void *closure)
 218 {
 219   struct symbol *symbol = NULL;
 220
 221   SYMPY_REQUIRE_VALID (self, symbol);
 222
 223   return PyInt_FromLong (SYMBOL_LINE (symbol));
 224 }
 225
 226 /* Implementation of gdb.Symbol.is_valid (self) -> Boolean.
 227    Returns True if this Symbol still exists in GDB.  */
 228
 229 static PyObject *
 230 sympy_is_valid (PyObject *self, PyObject *args)
 231 {
 232   struct symbol *symbol = NULL;
 233
 234   symbol = symbol_object_to_symbol (self);
 235   if (symbol == NULL)
 236     Py_RETURN_FALSE;
 237
 238   Py_RETURN_TRUE;
 239 }
 240
 241 /* Implementation of gdb.Symbol.value (self[, frame]) -> gdb.Value.  Returns
 242    the value of the symbol, or an error in various circumstances.  */
 243
 244 static PyObject *
 245 sympy_value (PyObject *self, PyObject *args)
 246 {
 247   struct symbol *symbol = NULL;
 248   struct frame_info *frame_info = NULL;
 249   PyObject *frame_obj = NULL;
 250   struct value *value = NULL;
 251
 252   if (!PyArg_ParseTuple (args, "|O", &frame_obj))
 253     return NULL;
 254
 255   if (frame_obj != NULL && !PyObject_TypeCheck (frame_obj, &frame_object_type))
 256     {
 257       PyErr_SetString (PyExc_TypeError, "argument is not a frame");
 258       return NULL;
 259     }
 260
 261   SYMPY_REQUIRE_VALID (self, symbol);
 262   if (SYMBOL_CLASS (symbol) == LOC_TYPEDEF)
 263     {
 264       PyErr_SetString (PyExc_TypeError, "cannot get the value of a typedef");
 265       return NULL;
 266     }
 267
 268   try
 269     {
 270       if (frame_obj != NULL)
 271         {
 272           frame_info = frame_object_to_frame_info (frame_obj);
 273           if (frame_info == NULL)
 274             error (_("invalid frame"));
 275         }
 276
 277       if (symbol_read_needs_frame (symbol) && frame_info == NULL)
 278         error (_("symbol requires a frame to compute its value"));
 279
 280       /* TODO: currently, we have no way to recover the block in which SYMBOL
 281          was found, so we have no block to pass to read_var_value.  This will
 282          yield an incorrect value when symbol is not local to FRAME_INFO (this
 283          can happen with nested functions).  */
 284       value = read_var_value (symbol, NULL, frame_info);
 285     }
 286   catch (const gdb_exception &except)
 287     {
 288       GDB_PY_HANDLE_EXCEPTION (except);
 289     }
 290
 291   return value_to_value_object (value);
 292 }
 293
 294 /* Given a symbol, and a symbol_object that has previously been
 295    allocated and initialized, populate the symbol_object with the
 296    struct symbol data.  Also, register the symbol_object life-cycle
 297    with the life-cycle of the object file associated with this
 298    symbol, if needed.  */
 299 static void
 300 set_symbol (symbol_object *obj, struct symbol *symbol)
 301 {
 302   obj->symbol = symbol;
 303   obj->prev = NULL;
 304   if (SYMBOL_OBJFILE_OWNED (symbol)
 305       && symbol_symtab (symbol) != NULL)
 306     {
 307       struct objfile *objfile = symbol_objfile (symbol);
 308
 309       obj->next = ((struct sympy_symbol_object *)
 310                    objfile_data (objfile, sympy_objfile_data_key));
 311       if (obj->next)
 312         obj->next->prev = obj;
 313       set_objfile_data (objfile, sympy_objfile_data_key, obj);
 314     }
 315   else
 316     obj->next = NULL;
 317 }
 318
 319 /* Create a new symbol object (gdb.Symbol) that encapsulates the struct
 320    symbol object from GDB.  */
 321 PyObject *
 322 symbol_to_symbol_object (struct symbol *sym)
 323 {
 324   symbol_object *sym_obj;
 325
 326   sym_obj = PyObject_New (symbol_object, &symbol_object_type);
 327   if (sym_obj)
 328     set_symbol (sym_obj, sym);
 329
 330   return (PyObject *) sym_obj;
 331 }
 332
 333 /* Return the symbol that is wrapped by this symbol object.  */
 334 struct symbol *
 335 symbol_object_to_symbol (PyObject *obj)
 336 {
 337   if (! PyObject_TypeCheck (obj, &symbol_object_type))
 338     return NULL;
 339   return ((symbol_object *) obj)->symbol;
 340 }
 341
 342 static void
 343 sympy_dealloc (PyObject *obj)
 344 {
 345   symbol_object *sym_obj = (symbol_object *) obj;
 346
 347   if (sym_obj->prev)
 348     sym_obj->prev->next = sym_obj->next;
 349   else if (sym_obj->symbol != NULL
 350            && SYMBOL_OBJFILE_OWNED (sym_obj->symbol)
 351            && symbol_symtab (sym_obj->symbol) != NULL)
 352     {
 353       set_objfile_data (symbol_objfile (sym_obj->symbol),
 354                         sympy_objfile_data_key, sym_obj->next);
 355     }
 356   if (sym_obj->next)
 357     sym_obj->next->prev = sym_obj->prev;
 358   sym_obj->symbol = NULL;
 359 }
 360
 361 /* Implementation of
 362    gdb.lookup_symbol (name [, block] [, domain]) -> (symbol, is_field_of_this)
 363    A tuple with 2 elements is always returned.  The first is the symbol
 364    object or None, the second is a boolean with the value of
 365    is_a_field_of_this (see comment in lookup_symbol_in_language).  */
 366
 367 PyObject *
 368 gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw)
 369 {
 370   int domain = VAR_DOMAIN;
 371   struct field_of_this_result is_a_field_of_this;
 372   const char *name;
 373   static const char *keywords[] = { "name", "block", "domain", NULL };
 374   struct symbol *symbol = NULL;
 375   PyObject *block_obj = NULL, *sym_obj, *bool_obj;
 376   const struct block *block = NULL;
 377
 378   if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|O!i", keywords, &name,
 379                                         &block_object_type, &block_obj,
 380                                         &domain))
 381     return NULL;
 382
 383   if (block_obj)
 384     block = block_object_to_block (block_obj);
 385   else
 386     {
 387       struct frame_info *selected_frame;
 388
 389       try
 390         {
 391           selected_frame = get_selected_frame (_("No frame selected."));
 392           block = get_frame_block (selected_frame, NULL);
 393         }
 394       catch (const gdb_exception &except)
 395         {
 396           GDB_PY_HANDLE_EXCEPTION (except);
 397         }
 398     }
 399
 400   try
 401     {
 402       symbol = lookup_symbol (name, block, (domain_enum) domain,
 403                               &is_a_field_of_this).symbol;
 404     }
 405   catch (const gdb_exception &except)
 406     {
 407       GDB_PY_HANDLE_EXCEPTION (except);
 408     }
 409
 410   gdbpy_ref<> ret_tuple (PyTuple_New (2));
 411   if (ret_tuple == NULL)
 412     return NULL;
 413
 414   if (symbol)
 415     {
 416       sym_obj = symbol_to_symbol_object (symbol);
 417       if (!sym_obj)
 418         return NULL;
 419     }
 420   else
 421     {
 422       sym_obj = Py_None;
 423       Py_INCREF (Py_None);
 424     }
 425   PyTuple_SET_ITEM (ret_tuple.get (), 0, sym_obj);
 426
 427   bool_obj = (is_a_field_of_this.type != NULL) ? Py_True : Py_False;
 428   Py_INCREF (bool_obj);
 429   PyTuple_SET_ITEM (ret_tuple.get (), 1, bool_obj);
 430
 431   return ret_tuple.release ();
 432 }
 433
 434 /* Implementation of
 435    gdb.lookup_global_symbol (name [, domain]) -> symbol or None.  */
 436
 437 PyObject *
 438 gdbpy_lookup_global_symbol (PyObject *self, PyObject *args, PyObject *kw)
 439 {
 440   int domain = VAR_DOMAIN;
 441   const char *name;
 442   static const char *keywords[] = { "name", "domain", NULL };
 443   struct symbol *symbol = NULL;
 444   PyObject *sym_obj;
 445
 446   if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &name,
 447                                         &domain))
 448     return NULL;
 449
 450   try
 451     {
 452       symbol = lookup_global_symbol (name, NULL, (domain_enum) domain).symbol;
 453     }
 454   catch (const gdb_exception &except)
 455     {
 456       GDB_PY_HANDLE_EXCEPTION (except);
 457     }
 458
 459   if (symbol)
 460     {
 461       sym_obj = symbol_to_symbol_object (symbol);
 462       if (!sym_obj)
 463         return NULL;
 464     }
 465   else
 466     {
 467       sym_obj = Py_None;
 468       Py_INCREF (Py_None);
 469     }
 470
 471   return sym_obj;
 472 }
 473
 474 /* This function is called when an objfile is about to be freed.
 475    Invalidate the symbol as further actions on the symbol would result
 476    in bad data.  All access to obj->symbol should be gated by
 477    SYMPY_REQUIRE_VALID which will raise an exception on invalid
 478    symbols.  */
 479 static void
 480 del_objfile_symbols (struct objfile *objfile, void *datum)
 481 {
 482   symbol_object *obj = (symbol_object *) datum;
 483   while (obj)
 484     {
 485       symbol_object *next = obj->next;
 486
 487       obj->symbol = NULL;
 488       obj->next = NULL;
 489       obj->prev = NULL;
 490
 491       obj = next;
 492     }
 493 }
 494
 495 int
 496 gdbpy_initialize_symbols (void)
 497 {
 498   if (PyType_Ready (&symbol_object_type) < 0)
 499     return -1;
 500
 501   /* Register an objfile "free" callback so we can properly
 502      invalidate symbol when an object file that is about to be
 503      deleted.  */
 504   sympy_objfile_data_key
 505     = register_objfile_data_with_cleanup (NULL, del_objfile_symbols);
 506
 507   if (PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNDEF", LOC_UNDEF) < 0
 508       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST",
 509                                   LOC_CONST) < 0
 510       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_STATIC",
 511                                   LOC_STATIC) < 0
 512       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGISTER",
 513                                   LOC_REGISTER) < 0
 514       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_ARG",
 515                                   LOC_ARG) < 0
 516       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REF_ARG",
 517                                   LOC_REF_ARG) < 0
 518       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LOCAL",
 519                                   LOC_LOCAL) < 0
 520       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_TYPEDEF",
 521                                   LOC_TYPEDEF) < 0
 522       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LABEL",
 523                                   LOC_LABEL) < 0
 524       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_BLOCK",
 525                                   LOC_BLOCK) < 0
 526       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST_BYTES",
 527                                   LOC_CONST_BYTES) < 0
 528       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNRESOLVED",
 529                                   LOC_UNRESOLVED) < 0
 530       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_OPTIMIZED_OUT",
 531                                   LOC_OPTIMIZED_OUT) < 0
 532       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMPUTED",
 533                                   LOC_COMPUTED) < 0
 534       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMMON_BLOCK",
 535                                   LOC_COMMON_BLOCK) < 0
 536       || PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGPARM_ADDR",
 537                                   LOC_REGPARM_ADDR) < 0
 538       || PyModule_AddIntConstant (gdb_module, "SYMBOL_UNDEF_DOMAIN",
 539                                   UNDEF_DOMAIN) < 0
 540       || PyModule_AddIntConstant (gdb_module, "SYMBOL_VAR_DOMAIN",
 541                                   VAR_DOMAIN) < 0
 542       || PyModule_AddIntConstant (gdb_module, "SYMBOL_STRUCT_DOMAIN",
 543                                   STRUCT_DOMAIN) < 0
 544       || PyModule_AddIntConstant (gdb_module, "SYMBOL_MODULE_DOMAIN",
 545                                   MODULE_DOMAIN) < 0
 546       || PyModule_AddIntConstant (gdb_module, "SYMBOL_COMMON_BLOCK_DOMAIN",
 547                                   COMMON_BLOCK_DOMAIN) < 0)
 548     return -1;
 549
 550   /* These remain defined for compatibility, but as they were never
 551      correct, they are no longer documented.  Eventually we can remove
 552      them.  These exist because at one time, enum search_domain and
 553      enum domain_enum_tag were combined -- but different values were
 554      used differently.  Here we try to give them values that will make
 555      sense if they are passed to gdb.lookup_symbol.  */
 556   if (PyModule_AddIntConstant (gdb_module, "SYMBOL_VARIABLES_DOMAIN",
 557                                VAR_DOMAIN) < 0
 558       || PyModule_AddIntConstant (gdb_module, "SYMBOL_FUNCTIONS_DOMAIN",
 559                                   VAR_DOMAIN) < 0
 560       || PyModule_AddIntConstant (gdb_module, "SYMBOL_TYPES_DOMAIN",
 561                                   VAR_DOMAIN) < 0)
 562     return -1;
 563
 564   return gdb_pymodule_addobject (gdb_module, "Symbol",
 565                                  (PyObject *) &symbol_object_type);
 566 }
 567
 568 \f
 569
 570 static gdb_PyGetSetDef symbol_object_getset[] = {
 571   { "type", sympy_get_type, NULL,
 572     "Type of the symbol.", NULL },
 573   { "symtab", sympy_get_symtab, NULL,
 574     "Symbol table in which the symbol appears.", NULL },
 575   { "name", sympy_get_name, NULL,
 576     "Name of the symbol, as it appears in the source code.", NULL },
 577   { "linkage_name", sympy_get_linkage_name, NULL,
 578     "Name of the symbol, as used by the linker (i.e., may be mangled).",
 579     NULL },
 580   { "print_name", sympy_get_print_name, NULL,
 581     "Name of the symbol in a form suitable for output.\n\
 582 This is either name or linkage_name, depending on whether the user asked GDB\n\
 583 to display demangled or mangled names.", NULL },
 584   { "addr_class", sympy_get_addr_class, NULL, "Address class of the symbol." },
 585   { "is_argument", sympy_is_argument, NULL,
 586     "True if the symbol is an argument of a function." },
 587   { "is_constant", sympy_is_constant, NULL,
 588     "True if the symbol is a constant." },
 589   { "is_function", sympy_is_function, NULL,
 590     "True if the symbol is a function or method." },
 591   { "is_variable", sympy_is_variable, NULL,
 592     "True if the symbol is a variable." },
 593   { "needs_frame", sympy_needs_frame, NULL,
 594     "True if the symbol requires a frame for evaluation." },
 595   { "line", sympy_line, NULL,
 596     "The source line number at which the symbol was defined." },
 597   { NULL }  /* Sentinel */
 598 };
 599
 600 static PyMethodDef symbol_object_methods[] = {
 601   { "is_valid", sympy_is_valid, METH_NOARGS,
 602     "is_valid () -> Boolean.\n\
 603 Return true if this symbol is valid, false if not." },
 604   { "value", sympy_value, METH_VARARGS,
 605     "value ([frame]) -> gdb.Value\n\
 606 Return the value of the symbol." },
 607   {NULL}  /* Sentinel */
 608 };
 609
 610 PyTypeObject symbol_object_type = {
 611   PyVarObject_HEAD_INIT (NULL, 0)
 612   "gdb.Symbol",                   /*tp_name*/
 613   sizeof (symbol_object),         /*tp_basicsize*/
 614   0,                              /*tp_itemsize*/
 615   sympy_dealloc,                  /*tp_dealloc*/
 616   0,                              /*tp_print*/
 617   0,                              /*tp_getattr*/
 618   0,                              /*tp_setattr*/
 619   0,                              /*tp_compare*/
 620   0,                              /*tp_repr*/
 621   0,                              /*tp_as_number*/
 622   0,                              /*tp_as_sequence*/
 623   0,                              /*tp_as_mapping*/
 624   0,                              /*tp_hash */
 625   0,                              /*tp_call*/
 626   sympy_str,                      /*tp_str*/
 627   0,                              /*tp_getattro*/
 628   0,                              /*tp_setattro*/
 629   0,                              /*tp_as_buffer*/
 630   Py_TPFLAGS_DEFAULT,             /*tp_flags*/
 631   "GDB symbol object",            /*tp_doc */
 632   0,                              /*tp_traverse */
 633   0,                              /*tp_clear */
 634   0,                              /*tp_richcompare */
 635   0,                              /*tp_weaklistoffset */
 636   0,                              /*tp_iter */
 637   0,                              /*tp_iternext */
 638   symbol_object_methods,          /*tp_methods */
 639   0,                              /*tp_members */
 640   symbol_object_getset            /*tp_getset */
 641 };