gdb/python/py-symbol.c

   1 /* Python interface to symbols.
   2
   3    Copyright (C) 2008, 2009, 2010, 2011 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_symtab (PyObject *self, void *closure)
  70 {
  71   struct symbol *symbol = NULL;
  72
  73   SYMPY_REQUIRE_VALID (self, symbol);
  74
  75   return symtab_to_symtab_object (SYMBOL_SYMTAB (symbol));
  76 }
  77
  78 static PyObject *
  79 sympy_get_name (PyObject *self, void *closure)
  80 {
  81   struct symbol *symbol = NULL;
  82
  83   SYMPY_REQUIRE_VALID (self, symbol);
  84
  85   return PyString_FromString (SYMBOL_NATURAL_NAME (symbol));
  86 }
  87
  88 static PyObject *
  89 sympy_get_linkage_name (PyObject *self, void *closure)
  90 {
  91   struct symbol *symbol = NULL;
  92
  93   SYMPY_REQUIRE_VALID (self, symbol);
  94
  95   return PyString_FromString (SYMBOL_LINKAGE_NAME (symbol));
  96 }
  97
  98 static PyObject *
  99 sympy_get_print_name (PyObject *self, void *closure)
 100 {
 101   struct symbol *symbol = NULL;
 102
 103   SYMPY_REQUIRE_VALID (self, symbol);
 104
 105   return sympy_str (self);
 106 }
 107
 108 static PyObject *
 109 sympy_get_addr_class (PyObject *self, void *closure)
 110 {
 111   struct symbol *symbol = NULL;
 112
 113   SYMPY_REQUIRE_VALID (self, symbol);
 114
 115   return PyInt_FromLong (SYMBOL_CLASS (symbol));
 116 }
 117
 118 static PyObject *
 119 sympy_is_argument (PyObject *self, void *closure)
 120 {
 121   struct symbol *symbol = NULL;
 122
 123   SYMPY_REQUIRE_VALID (self, symbol);
 124
 125   return PyBool_FromLong (SYMBOL_IS_ARGUMENT (symbol));
 126 }
 127
 128 static PyObject *
 129 sympy_is_constant (PyObject *self, void *closure)
 130 {
 131   struct symbol *symbol = NULL;
 132   enum address_class class;
 133
 134   SYMPY_REQUIRE_VALID (self, symbol);
 135
 136   class = SYMBOL_CLASS (symbol);
 137
 138   return PyBool_FromLong (class == LOC_CONST || class == LOC_CONST_BYTES);
 139 }
 140
 141 static PyObject *
 142 sympy_is_function (PyObject *self, void *closure)
 143 {
 144   struct symbol *symbol = NULL;
 145   enum address_class class;
 146
 147   SYMPY_REQUIRE_VALID (self, symbol);
 148
 149   class = SYMBOL_CLASS (symbol);
 150
 151   return PyBool_FromLong (class == LOC_BLOCK);
 152 }
 153
 154 static PyObject *
 155 sympy_is_variable (PyObject *self, void *closure)
 156 {
 157   struct symbol *symbol = NULL;
 158   enum address_class class;
 159
 160   SYMPY_REQUIRE_VALID (self, symbol);
 161
 162   class = SYMBOL_CLASS (symbol);
 163
 164   return PyBool_FromLong (!SYMBOL_IS_ARGUMENT (symbol)
 165                           && (class == LOC_LOCAL || class == LOC_REGISTER
 166                               || class == LOC_STATIC || class == LOC_COMPUTED
 167                               || class == LOC_OPTIMIZED_OUT));
 168 }
 169
 170 /* Given a symbol, and a symbol_object that has previously been
 171    allocated and initialized, populate the symbol_object with the
 172    struct symbol data.  Also, register the symbol_object life-cycle
 173    with the life-cycle of the the object file associated with this
 174    symbol, if needed.  */
 175 static void
 176 set_symbol (symbol_object *obj, struct symbol *symbol)
 177 {
 178   obj->symbol = symbol;
 179   obj->prev = NULL;
 180   if (SYMBOL_SYMTAB (symbol))
 181     {
 182       obj->next = objfile_data (SYMBOL_SYMTAB (symbol)->objfile,
 183                                 sympy_objfile_data_key);
 184
 185       if (obj->next)
 186         obj->next->prev = obj;
 187       set_objfile_data (SYMBOL_SYMTAB (symbol)->objfile,
 188                         sympy_objfile_data_key, obj);
 189     }
 190   else
 191     obj->next = NULL;
 192 }
 193
 194 /* Create a new symbol object (gdb.Symbol) that encapsulates the struct
 195    symbol object from GDB.  */
 196 PyObject *
 197 symbol_to_symbol_object (struct symbol *sym)
 198 {
 199   symbol_object *sym_obj;
 200
 201   sym_obj = PyObject_New (symbol_object, &symbol_object_type);
 202   if (sym_obj)
 203     set_symbol (sym_obj, sym);
 204
 205   return (PyObject *) sym_obj;
 206 }
 207
 208 /* Return the symbol that is wrapped by this symbol object.  */
 209 struct symbol *
 210 symbol_object_to_symbol (PyObject *obj)
 211 {
 212   if (! PyObject_TypeCheck (obj, &symbol_object_type))
 213     return NULL;
 214   return ((symbol_object *) obj)->symbol;
 215 }
 216
 217 static void
 218 sympy_dealloc (PyObject *obj)
 219 {
 220   symbol_object *sym_obj = (symbol_object *) obj;
 221
 222   if (sym_obj->prev)
 223     sym_obj->prev->next = sym_obj->next;
 224   else if (SYMBOL_SYMTAB (sym_obj->symbol))
 225     {
 226       set_objfile_data (SYMBOL_SYMTAB (sym_obj->symbol)->objfile,
 227                         sympy_objfile_data_key, sym_obj->next);
 228     }
 229   if (sym_obj->next)
 230     sym_obj->next->prev = sym_obj->prev;
 231   sym_obj->symbol = NULL;
 232 }
 233
 234 /* Implementation of
 235    gdb.lookup_symbol (name [, block] [, domain]) -> (symbol, is_field_of_this)
 236    A tuple with 2 elements is always returned.  The first is the symbol
 237    object or None, the second is a boolean with the value of
 238    is_a_field_of_this (see comment in lookup_symbol_in_language).  */
 239 PyObject *
 240 gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw)
 241 {
 242   int domain = VAR_DOMAIN, is_a_field_of_this = 0;
 243   const char *name;
 244   static char *keywords[] = { "name", "block", "domain", NULL };
 245   struct symbol *symbol;
 246   PyObject *block_obj = NULL, *ret_tuple, *sym_obj, *bool_obj;
 247   struct block *block = NULL;
 248
 249   if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!i", keywords, &name,
 250                                      &block_object_type, &block_obj, &domain))
 251     return NULL;
 252
 253   if (block_obj)
 254     block = block_object_to_block (block_obj);
 255   else
 256     {
 257       struct frame_info *selected_frame;
 258       volatile struct gdb_exception except;
 259
 260       TRY_CATCH (except, RETURN_MASK_ALL)
 261         {
 262           selected_frame  = get_selected_frame (_("No frame selected."));
 263           block = block_for_pc (get_frame_address_in_block (selected_frame));
 264         }
 265       GDB_PY_HANDLE_EXCEPTION (except);
 266     }
 267
 268   symbol = lookup_symbol (name, block, domain, &is_a_field_of_this);
 269
 270   ret_tuple = PyTuple_New (2);
 271   if (!ret_tuple)
 272     return NULL;
 273
 274   if (symbol)
 275     {
 276       sym_obj = symbol_to_symbol_object (symbol);
 277       if (!sym_obj)
 278         {
 279           Py_DECREF (ret_tuple);
 280           return NULL;
 281         }
 282     }
 283   else
 284     {
 285       sym_obj = Py_None;
 286       Py_INCREF (Py_None);
 287     }
 288   PyTuple_SET_ITEM (ret_tuple, 0, sym_obj);
 289
 290   bool_obj = is_a_field_of_this? Py_True : Py_False;
 291   Py_INCREF (bool_obj);
 292   PyTuple_SET_ITEM (ret_tuple, 1, bool_obj);
 293
 294   return ret_tuple;
 295 }
 296
 297 /* This function is called when an objfile is about to be freed.
 298    Invalidate the symbol as further actions on the symbol would result
 299    in bad data.  All access to obj->symbol should be gated by
 300    SYMPY_REQUIRE_VALID which will raise an exception on invalid
 301    symbols.  */
 302 static void
 303 del_objfile_symbols (struct objfile *objfile, void *datum)
 304 {
 305   symbol_object *obj = datum;
 306   while (obj)
 307     {
 308       symbol_object *next = obj->next;
 309
 310       obj->symbol = NULL;
 311       obj->next = NULL;
 312       obj->prev = NULL;
 313
 314       obj = next;
 315     }
 316 }
 317
 318 void
 319 gdbpy_initialize_symbols (void)
 320 {
 321   if (PyType_Ready (&symbol_object_type) < 0)
 322     return;
 323
 324   /* Register an objfile "free" callback so we can properly
 325      invalidate symbol when an object file that is about to be
 326      deleted.  */
 327   sympy_objfile_data_key
 328     = register_objfile_data_with_cleanup (NULL, del_objfile_symbols);
 329
 330   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNDEF", LOC_UNDEF);
 331   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST", LOC_CONST);
 332   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_STATIC", LOC_STATIC);
 333   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGISTER", LOC_REGISTER);
 334   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_ARG", LOC_ARG);
 335   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REF_ARG", LOC_REF_ARG);
 336   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LOCAL", LOC_LOCAL);
 337   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_TYPEDEF", LOC_TYPEDEF);
 338   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LABEL", LOC_LABEL);
 339   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_BLOCK", LOC_BLOCK);
 340   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST_BYTES",
 341                            LOC_CONST_BYTES);
 342   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNRESOLVED", LOC_UNRESOLVED);
 343   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_OPTIMIZED_OUT",
 344                            LOC_OPTIMIZED_OUT);
 345   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMPUTED", LOC_COMPUTED);
 346   PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGPARM_ADDR",
 347                            LOC_REGPARM_ADDR);
 348   PyModule_AddIntConstant (gdb_module, "SYMBOL_UNDEF_DOMAIN", UNDEF_DOMAIN);
 349   PyModule_AddIntConstant (gdb_module, "SYMBOL_VAR_DOMAIN", VAR_DOMAIN);
 350   PyModule_AddIntConstant (gdb_module, "SYMBOL_STRUCT_DOMAIN", STRUCT_DOMAIN);
 351   PyModule_AddIntConstant (gdb_module, "SYMBOL_LABEL_DOMAIN", LABEL_DOMAIN);
 352   PyModule_AddIntConstant (gdb_module, "SYMBOL_VARIABLES_DOMAIN",
 353                            VARIABLES_DOMAIN);
 354   PyModule_AddIntConstant (gdb_module, "SYMBOL_FUNCTIONS_DOMAIN",
 355                            FUNCTIONS_DOMAIN);
 356   PyModule_AddIntConstant (gdb_module, "SYMBOL_TYPES_DOMAIN", TYPES_DOMAIN);
 357
 358   Py_INCREF (&symbol_object_type);
 359   PyModule_AddObject (gdb_module, "Symbol", (PyObject *) &symbol_object_type);
 360 }
 361
 362 \f
 363
 364 static PyGetSetDef symbol_object_getset[] = {
 365   { "symtab", sympy_get_symtab, NULL,
 366     "Symbol table in which the symbol appears.", NULL },
 367   { "name", sympy_get_name, NULL,
 368     "Name of the symbol, as it appears in the source code.", NULL },
 369   { "linkage_name", sympy_get_linkage_name, NULL,
 370     "Name of the symbol, as used by the linker (i.e., may be mangled).", NULL },
 371   { "print_name", sympy_get_print_name, NULL,
 372     "Name of the symbol in a form suitable for output.\n\
 373 This is either name or linkage_name, depending on whether the user asked GDB\n\
 374 to display demangled or mangled names.", NULL },
 375   { "addr_class", sympy_get_addr_class, NULL, "Address class of the symbol." },
 376   { "is_argument", sympy_is_argument, NULL,
 377     "True if the symbol is an argument of a function." },
 378   { "is_constant", sympy_is_constant, NULL,
 379     "True if the symbol is a constant." },
 380   { "is_function", sympy_is_function, NULL,
 381     "True if the symbol is a function or method." },
 382   { "is_variable", sympy_is_variable, NULL,
 383     "True if the symbol is a variable." },
 384   { NULL }  /* Sentinel */
 385 };
 386
 387 PyTypeObject symbol_object_type = {
 388   PyObject_HEAD_INIT (NULL)
 389   0,                              /*ob_size*/
 390   "gdb.Symbol",                   /*tp_name*/
 391   sizeof (symbol_object),         /*tp_basicsize*/
 392   0,                              /*tp_itemsize*/
 393   sympy_dealloc,                  /*tp_dealloc*/
 394   0,                              /*tp_print*/
 395   0,                              /*tp_getattr*/
 396   0,                              /*tp_setattr*/
 397   0,                              /*tp_compare*/
 398   0,                              /*tp_repr*/
 399   0,                              /*tp_as_number*/
 400   0,                              /*tp_as_sequence*/
 401   0,                              /*tp_as_mapping*/
 402   0,                              /*tp_hash */
 403   0,                              /*tp_call*/
 404   sympy_str,                      /*tp_str*/
 405   0,                              /*tp_getattro*/
 406   0,                              /*tp_setattro*/
 407   0,                              /*tp_as_buffer*/
 408   Py_TPFLAGS_DEFAULT,             /*tp_flags*/
 409   "GDB symbol object",            /*tp_doc */
 410   0,                              /*tp_traverse */
 411   0,                              /*tp_clear */
 412   0,                              /*tp_richcompare */
 413   0,                              /*tp_weaklistoffset */
 414   0,                              /*tp_iter */
 415   0,                              /*tp_iternext */
 416   0,                              /*tp_methods */
 417   0,                              /*tp_members */
 418   symbol_object_getset            /*tp_getset */
 419 };