gdb/python/py-symbol.c

   1 /* Python interface to symbols.
   2
   3    Copyright (C) 2008-2012 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 "exceptions.h"
  23 #include "frame.h"
  24 #include "symtab.h"
  25 #include "python-internal.h"
  26 #include "objfiles.h"
  27
  28 typedef struct sympy_symbol_object {
  29   PyObject_HEAD
  30   /* The GDB symbol structure this object is wrapping.  */
  31   struct symbol *symbol;
  32   /* A symbol object is associated with an objfile, so keep track with
  33      doubly-linked list, rooted in the objfile.  This lets us
  34      invalidate the underlying struct symbol when the objfile is
  35      deleted.  */
  36   struct sympy_symbol_object *prev;
  37   struct sympy_symbol_object *next;
  38 } symbol_object;
  39
  40 /* Require a valid symbol.  All access to symbol_object->symbol should be
  41    gated by this call.  */
  42 #define SYMPY_REQUIRE_VALID(symbol_obj, symbol)         \
  43   do {                                                  \
  44     symbol = symbol_object_to_symbol (symbol_obj);      \
  45     if (symbol == NULL)                                 \
  46       {                                                 \
  47         PyErr_SetString (PyExc_RuntimeError,            \
  48                          _("Symbol is invalid."));      \
  49         return NULL;                                    \
  50       }                                                 \
  51   } while (0)
  52
  53 static const struct objfile_data *sympy_objfile_data_key;
  54
  55 static PyObject *
  56 sympy_str (PyObject *self)
  57 {
  58   PyObject *result;
  59   struct symbol *symbol = NULL;
  60
  61   SYMPY_REQUIRE_VALID (self, symbol);
  62
  63   result = PyString_FromString (SYMBOL_PRINT_NAME (symbol));
  64
  65   return result;
  66 }
  67
  68 static PyObject *
  69 sympy_get_type (PyObject *self, void *closure)
  70 {
  71   struct symbol *symbol = NULL;
  72
  73   SYMPY_REQUIRE_VALID (self, symbol);
  74
  75   if (SYMBOL_TYPE (symbol) == NULL)
  76     {
  77       Py_INCREF (Py_None);
  78       return Py_None;
  79     }
  80
  81   return type_to_type_object (SYMBOL_TYPE (symbol));
  82 }
  83
  84 static PyObject *
  85 sympy_get_symtab (PyObject *self, void *closure)
  86 {
  87   struct symbol *symbol = NULL;
  88
  89   SYMPY_REQUIRE_VALID (self, symbol);
  90
  91   return symtab_to_symtab_object (SYMBOL_SYMTAB (symbol));
  92 }
  93
  94 static PyObject *
  95 sympy_get_name (PyObject *self, void *closure)
  96 {
  97   struct symbol *symbol = NULL;
  98
  99   SYMPY_REQUIRE_VALID (self, symbol);
 100
 101   return PyString_FromString (SYMBOL_NATURAL_NAME (symbol));
 102 }
 103
 104 static PyObject *
 105 sympy_get_linkage_name (PyObject *self, void *closure)
 106 {
 107   struct symbol *symbol = NULL;
 108
 109   SYMPY_REQUIRE_VALID (self, symbol);
 110
 111   return PyString_FromString (SYMBOL_LINKAGE_NAME (symbol));
 112 }
 113
 114 static PyObject *
 115 sympy_get_print_name (PyObject *self, void *closure)
 116 {
 117   struct symbol *symbol = NULL;
 118
 119   SYMPY_REQUIRE_VALID (self, symbol);
 120
 121   return sympy_str (self);
 122 }
 123
 124 static PyObject *
 125 sympy_get_addr_class (PyObject *self, void *closure)
 126 {
 127   struct symbol *symbol = NULL;
 128
 129   SYMPY_REQUIRE_VALID (self, symbol);
 130
 131   return PyInt_FromLong (SYMBOL_CLASS (symbol));
 132 }
 133
 134 static PyObject *
 135 sympy_is_argument (PyObject *self, void *closure)
 136 {
 137   struct symbol *symbol = NULL;
 138
 139   SYMPY_REQUIRE_VALID (self, symbol);
 140
 141   return PyBool_FromLong (SYMBOL_IS_ARGUMENT (symbol));
 142 }
 143
 144 static PyObject *
 145 sympy_is_constant (PyObject *self, void *closure)
 146 {
 147   struct symbol *symbol = NULL;
 148   enum address_class class;
 149
 150   SYMPY_REQUIRE_VALID (self, symbol);
 151
 152   class = SYMBOL_CLASS (symbol);
 153
 154   return PyBool_FromLong (class == LOC_CONST || class == LOC_CONST_BYTES);
 155 }
 156
 157 static PyObject *
 158 sympy_is_function (PyObject *self, void *closure)
 159 {
 160   struct symbol *symbol = NULL;
 161   enum address_class class;
 162
 163   SYMPY_REQUIRE_VALID (self, symbol);
 164
 165   class = SYMBOL_CLASS (symbol);
 166
 167   return PyBool_FromLong (class == LOC_BLOCK);
 168 }
 169
 170 static PyObject *
 171 sympy_is_variable (PyObject *self, void *closure)
 172 {
 173   struct symbol *symbol = NULL;
 174   enum address_class class;
 175
 176   SYMPY_REQUIRE_VALID (self, symbol);
 177
 178   class = SYMBOL_CLASS (symbol);
 179
 180   return PyBool_FromLong (!SYMBOL_IS_ARGUMENT (symbol)
 181                           && (class == LOC_LOCAL || class == LOC_REGISTER
 182                               || class == LOC_STATIC || class == LOC_COMPUTED
 183                               || class == LOC_OPTIMIZED_OUT));
 184 }
 185
 186 /* Implementation of gdb.Symbol.needs_frame -> Boolean.
 187    Returns true iff the symbol needs a frame for evaluation.  */
 188
 189 static PyObject *
 190 sympy_needs_frame (PyObject *self, void *closure)
 191 {
 192   struct symbol *symbol = NULL;
 193   volatile struct gdb_exception except;
 194   int result = 0;
 195
 196   SYMPY_REQUIRE_VALID (self, symbol);
 197
 198   TRY_CATCH (except, RETURN_MASK_ALL)
 199     {
 200       result = symbol_read_needs_frame (symbol);
 201     }
 202   GDB_PY_HANDLE_EXCEPTION (except);
 203
 204   if (result)
 205     Py_RETURN_TRUE;
 206   Py_RETURN_FALSE;
 207 }
 208
 209 /* Implementation of gdb.Symbol.line -> int.
 210    Returns the line number at which the symbol was defined.  */
 211
 212 static PyObject *
 213 sympy_line (PyObject *self, void *closure)
 214 {
 215   struct symbol *symbol = NULL;
 216
 217   SYMPY_REQUIRE_VALID (self, symbol);
 218
 219   return PyInt_FromLong (SYMBOL_LINE (symbol));
 220 }
 221
 222 /* Implementation of gdb.Symbol.is_valid (self) -> Boolean.
 223    Returns True if this Symbol still exists in GDB.  */
 224
 225 static PyObject *
 226 sympy_is_valid (PyObject *self, PyObject *args)
 227 {
 228   struct symbol *symbol = NULL;
 229
 230   symbol = symbol_object_to_symbol (self);
 231   if (symbol == NULL)
 232     Py_RETURN_FALSE;
 233
 234   Py_RETURN_TRUE;
 235 }
 236
 237 /* Implementation of gdb.Symbol.value (self[, frame]) -> gdb.Value.  Returns
 238    the value of the symbol, or an error in various circumstances.  */
 239
 240 static PyObject *
 241 sympy_value (PyObject *self, PyObject *args)
 242 {
 243   struct symbol *symbol = NULL;
 244   struct frame_info *frame_info = NULL;
 245   PyObject *frame_obj = NULL;
 246   struct value *value = NULL;
 247   volatile struct gdb_exception except;
 248
 249   if (!PyArg_ParseTuple (args, "|O", &frame_obj))
 250     return NULL;
 251
 252   if (frame_obj != NULL && !PyObject_TypeCheck (frame_obj, &frame_object_type))
 253     {
 254       PyErr_SetString (PyExc_TypeError, "argument is not a frame");
 255       return NULL;
 256     }
 257
 258   SYMPY_REQUIRE_VALID (self, symbol);
 259   if (SYMBOL_CLASS (symbol) == LOC_TYPEDEF)
 260     {
 261       PyErr_SetString (PyExc_TypeError, "cannot get the value of a typedef");
 262       return NULL;
 263     }
 264
 265   TRY_CATCH (except, RETURN_MASK_ALL)
 266     {
 267       if (frame_obj != NULL)
 268         {
 269           frame_info = frame_object_to_frame_info (frame_obj);
 270           if (frame_info == NULL)
 271             error (_("invalid frame"));
 272         }
 273
 274       if (symbol_read_needs_frame (symbol) && frame_info == NULL)
 275         error (_("symbol requires a frame to compute its value"));
 276
 277       value = read_var_value (symbol, frame_info);
 278     }
 279   GDB_PY_HANDLE_EXCEPTION (except);
 280
 281   return value_to_value_object (value);
 282 }
 283
 284 /* Given a symbol, and a symbol_object that has previously been
 285    allocated and initialized, populate the symbol_object with the
 286    struct symbol data.  Also, register the symbol_object life-cycle
 287    with the life-cycle of the object file associated with this
 288    symbol, if needed.  */
 289 static void
 290 set_symbol (symbol_object *obj, struct symbol *symbol)
 291 {
 292   obj->symbol = symbol;
 293   obj->prev = NULL;
 294   if (SYMBOL_SYMTAB (symbol))
 295     {
 296       obj->next = objfile_data (SYMBOL_SYMTAB (symbol)->objfile,
 297                                 sympy_objfile_data_key);
 298
 299       if (obj->next)
 300         obj->next->prev = obj;
 301       set_objfile_data (SYMBOL_SYMTAB (symbol)->objfile,
 302                         sympy_objfile_data_key, obj);
 303     }
 304   else
 305     obj->next = NULL;
 306 }
 307
 308 /* Create a new symbol object (gdb.Symbol) that encapsulates the struct
 309    symbol object from GDB.  */
 310 PyObject *
 311 symbol_to_symbol_object (struct symbol *sym)
 312 {
 313   symbol_object *sym_obj;
 314
 315   sym_obj = PyObject_New (symbol_object, &symbol_object_type);
 316   if (sym_obj)
 317     set_symbol (sym_obj, sym);
 318
 319   return (PyObject *) sym_obj;
 320 }
 321
 322 /* Return the symbol that is wrapped by this symbol object.  */
 323 struct symbol *
 324 symbol_object_to_symbol (PyObject *obj)
 325 {
 326   if (! PyObject_TypeCheck (obj, &symbol_object_type))
 327     return NULL;
 328   return ((symbol_object *) obj)->symbol;
 329 }
 330
 331 static void
 332 sympy_dealloc (PyObject *obj)
 333 {
 334   symbol_object *sym_obj = (symbol_object *) obj;
 335
 336   if (sym_obj->prev)
 337     sym_obj->prev->next = sym_obj->next;
 338   else if (sym_obj->symbol && SYMBOL_SYMTAB (sym_obj->symbol))
 339     {
 340       set_objfile_data (SYMBOL_SYMTAB (sym_obj->symbol)->objfile,
 341                         sympy_objfile_data_key, sym_obj->next);
 342     }
 343   if (sym_obj->next)
 344     sym_obj->next->prev = sym_obj->prev;
 345   sym_obj->symbol = NULL;
 346 }
 347
 348 /* Implementation of
 349    gdb.lookup_symbol (name [, block] [, domain]) -> (symbol, is_field_of_this)
 350    A tuple with 2 elements is always returned.  The first is the symbol
 351    object or None, the second is a boolean with the value of
 352    is_a_field_of_this (see comment in lookup_symbol_in_language).  */
 353
 354 PyObject *
 355 gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw)
 356 {
 357   int domain = VAR_DOMAIN, is_a_field_of_this = 0;
 358   const char *name;
 359   static char *keywords[] = { "name", "block", "domain", NULL };
 360   struct symbol *symbol = NULL;
 361   PyObject *block_obj = NULL, *ret_tuple, *sym_obj, *bool_obj;
 362   const struct block *block = NULL;
 363   volatile struct gdb_exception except;
 364
 365   if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!i", keywords, &name,
 366                                      &block_object_type, &block_obj, &domain))
 367     return NULL;
 368
 369   if (block_obj)
 370     block = block_object_to_block (block_obj);
 371   else
 372     {
 373       struct frame_info *selected_frame;
 374       volatile struct gdb_exception except;
 375
 376       TRY_CATCH (except, RETURN_MASK_ALL)
 377         {
 378           selected_frame = get_selected_frame (_("No frame selected."));
 379           block = get_frame_block (selected_frame, NULL);
 380         }
 381       GDB_PY_HANDLE_EXCEPTION (except);
 382     }
 383
 384   TRY_CATCH (except, RETURN_MASK_ALL)
 385     {
 386       symbol = lookup_symbol (name, block, domain, &is_a_field_of_this);
 387     }
 388   GDB_PY_HANDLE_EXCEPTION (except);
 389
 390   ret_tuple = PyTuple_New (2);
 391   if (!ret_tuple)
 392     return NULL;
 393
 394   if (symbol)
 395     {
 396       sym_obj = symbol_to_symbol_object (symbol);
 397       if (!sym_obj)
 398         {
 399           Py_DECREF (ret_tuple);
 400           return NULL;
 401         }
 402     }
 403   else
 404     {
 405       sym_obj = Py_None;
 406       Py_INCREF (Py_None);
 407     }
 408   PyTuple_SET_ITEM (ret_tuple, 0, sym_obj);
 409
 410   bool_obj = is_a_field_of_this? Py_True : Py_False;
 411   Py_INCREF (bool_obj);
 412   PyTuple_SET_ITEM (ret_tuple, 1, bool_obj);
 413
 414   return ret_tuple;
 415 }
 416
 417 /* Implementation of
 418    gdb.lookup_global_symbol (name [, domain]) -> symbol or None.  */
 419
 420 PyObject *
 421 gdbpy_lookup_global_symbol (PyObject *self, PyObject *args, PyObject *kw)
 422 {
 423   int domain = VAR_DOMAIN;
 424   const char *name;
 425   static char *keywords[] = { "name", "domain", NULL };
 426   struct symbol *symbol = NULL;
 427   PyObject *sym_obj;
 428   volatile struct gdb_exception except;
 429
 430   if (! PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &name,
 431                                      &domain))
 432     return NULL;
 433
 434   TRY_CATCH (except, RETURN_MASK_ALL)
 435     {
 436       symbol = lookup_symbol_global (name, NULL, domain);
 437     }
 438   GDB_PY_HANDLE_EXCEPTION (except);
 439
 440   if (symbol)
 441     {
 442       sym_obj = symbol_to_symbol_object (symbol);
 443       if (!sym_obj)
 444         return NULL;
 445     }
 446   else
 447     {
 448       sym_obj = Py_None;
 449       Py_INCREF (Py_None);
 450     }
 451
 452   return sym_obj;
 453 }
 454
 455 /* This function is called when an objfile is about to be freed.
 456    Invalidate the symbol as further actions on the symbol would result
 457    in bad data.  All access to obj->symbol should be gated by
 458    SYMPY_REQUIRE_VALID which will raise an exception on invalid
 459    symbols.  */
 460 static void
 461 del_objfile_symbols (struct objfile *objfile, void *datum)
 462 {
 463   symbol_object *obj = datum;
 464   while (obj)
 465     {
 466       symbol_object *next = obj->next;
 467
 468       obj->symbol = NULL;
 469       obj->next = NULL;
 470       obj->prev = NULL;
 471
 472       obj = next;
 473     }
 474 }
 475
 476 void
 477 gdbpy_initialize_symbols (void)
 478 {
 479   if (PyType_Ready (&symbol_object_type) < 0)
 480     return;
 481
 482   /* Register an objfile "free" callback so we can properly
 483      invalidate symbol when an object file that is about to be
 484      deleted.  */
 485   sympy_objfile_data_key
 486     = register_objfile_data_with_cleanup (NULL, del_objfile_symbols);
 487
 488   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNDEF", LOC_UNDEF);
 489   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST", LOC_CONST);
 490   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_STATIC", LOC_STATIC);
 491   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGISTER", LOC_REGISTER);
 492   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_ARG", LOC_ARG);
 493   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REF_ARG", LOC_REF_ARG);
 494   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LOCAL", LOC_LOCAL);
 495   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_TYPEDEF", LOC_TYPEDEF);
 496   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LABEL", LOC_LABEL);
 497   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_BLOCK", LOC_BLOCK);
 498   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST_BYTES",
 499                            LOC_CONST_BYTES);
 500   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNRESOLVED",
 501                            LOC_UNRESOLVED);
 502   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_OPTIMIZED_OUT",
 503                            LOC_OPTIMIZED_OUT);
 504   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMPUTED", LOC_COMPUTED);
 505   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGPARM_ADDR",
 506                            LOC_REGPARM_ADDR);
 507   PyModule_AddIntConstant (gdb_module, "SYMBOL_UNDEF_DOMAIN", UNDEF_DOMAIN);
 508   PyModule_AddIntConstant (gdb_module, "SYMBOL_VAR_DOMAIN", VAR_DOMAIN);
 509   PyModule_AddIntConstant (gdb_module, "SYMBOL_STRUCT_DOMAIN", STRUCT_DOMAIN);
 510   PyModule_AddIntConstant (gdb_module, "SYMBOL_LABEL_DOMAIN", LABEL_DOMAIN);
 511   PyModule_AddIntConstant (gdb_module, "SYMBOL_VARIABLES_DOMAIN",
 512                            VARIABLES_DOMAIN);
 513   PyModule_AddIntConstant (gdb_module, "SYMBOL_FUNCTIONS_DOMAIN",
 514                            FUNCTIONS_DOMAIN);
 515   PyModule_AddIntConstant (gdb_module, "SYMBOL_TYPES_DOMAIN", TYPES_DOMAIN);
 516
 517   Py_INCREF (&symbol_object_type);
 518   PyModule_AddObject (gdb_module, "Symbol", (PyObject *) &symbol_object_type);
 519 }
 520
 521 \f
 522
 523 static PyGetSetDef symbol_object_getset[] = {
 524   { "type", sympy_get_type, NULL,
 525     "Type of the symbol.", NULL },
 526   { "symtab", sympy_get_symtab, NULL,
 527     "Symbol table in which the symbol appears.", NULL },
 528   { "name", sympy_get_name, NULL,
 529     "Name of the symbol, as it appears in the source code.", NULL },
 530   { "linkage_name", sympy_get_linkage_name, NULL,
 531     "Name of the symbol, as used by the linker (i.e., may be mangled).",
 532     NULL },
 533   { "print_name", sympy_get_print_name, NULL,
 534     "Name of the symbol in a form suitable for output.\n\
 535 This is either name or linkage_name, depending on whether the user asked GDB\n\
 536 to display demangled or mangled names.", NULL },
 537   { "addr_class", sympy_get_addr_class, NULL, "Address class of the symbol." },
 538   { "is_argument", sympy_is_argument, NULL,
 539     "True if the symbol is an argument of a function." },
 540   { "is_constant", sympy_is_constant, NULL,
 541     "True if the symbol is a constant." },
 542   { "is_function", sympy_is_function, NULL,
 543     "True if the symbol is a function or method." },
 544   { "is_variable", sympy_is_variable, NULL,
 545     "True if the symbol is a variable." },
 546   { "needs_frame", sympy_needs_frame, NULL,
 547     "True if the symbol requires a frame for evaluation." },
 548   { "line", sympy_line, NULL,
 549     "The source line number at which the symbol was defined." },
 550   { NULL }  /* Sentinel */
 551 };
 552
 553 static PyMethodDef symbol_object_methods[] = {
 554   { "is_valid", sympy_is_valid, METH_NOARGS,
 555     "is_valid () -> Boolean.\n\
 556 Return true if this symbol is valid, false if not." },
 557   { "value", sympy_value, METH_VARARGS,
 558     "value ([frame]) -> gdb.Value\n\
 559 Return the value of the symbol." },
 560   {NULL}  /* Sentinel */
 561 };
 562
 563 PyTypeObject symbol_object_type = {
 564   PyObject_HEAD_INIT (NULL)
 565   0,                              /*ob_size*/
 566   "gdb.Symbol",                   /*tp_name*/
 567   sizeof (symbol_object),         /*tp_basicsize*/
 568   0,                              /*tp_itemsize*/
 569   sympy_dealloc,                  /*tp_dealloc*/
 570   0,                              /*tp_print*/
 571   0,                              /*tp_getattr*/
 572   0,                              /*tp_setattr*/
 573   0,                              /*tp_compare*/
 574   0,                              /*tp_repr*/
 575   0,                              /*tp_as_number*/
 576   0,                              /*tp_as_sequence*/
 577   0,                              /*tp_as_mapping*/
 578   0,                              /*tp_hash */
 579   0,                              /*tp_call*/
 580   sympy_str,                      /*tp_str*/
 581   0,                              /*tp_getattro*/
 582   0,                              /*tp_setattro*/
 583   0,                              /*tp_as_buffer*/
 584   Py_TPFLAGS_DEFAULT,             /*tp_flags*/
 585   "GDB symbol object",            /*tp_doc */
 586   0,                              /*tp_traverse */
 587   0,                              /*tp_clear */
 588   0,                              /*tp_richcompare */
 589   0,                              /*tp_weaklistoffset */
 590   0,                              /*tp_iter */
 591   0,                              /*tp_iternext */
 592   symbol_object_methods,          /*tp_methods */
 593   0,                              /*tp_members */
 594   symbol_object_getset            /*tp_getset */
 595 };