gdb/python/py-block.c

   1 /* Python interface to blocks.
   2
   3    Copyright (C) 2008, 2009, 2010 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 "dictionary.h"
  23 #include "symtab.h"
  24 #include "python-internal.h"
  25 #include "objfiles.h"
  26 #include "symtab.h"
  27
  28 typedef struct blpy_block_object {
  29   PyObject_HEAD
  30   /* The GDB block structure that represents a frame's code block.  */
  31   struct block *block;
  32   /* The backing object file.  There is no direct relationship in GDB
  33      between a block and an object file.  When a block is created also
  34      store a pointer to the object file for later use.  */
  35   struct objfile *objfile;
  36   /* Keep track of all blocks with a doubly-linked list.  Needed for
  37      block invalidation if the source object file has been freed.  */
  38   struct blpy_block_object *prev;
  39   struct blpy_block_object *next;
  40 } block_object;
  41
  42 typedef struct {
  43   PyObject_HEAD
  44   /* The block dictionary of symbols.  */
  45   struct dictionary *dict;
  46   /* The iterator for that dictionary.  */
  47   struct dict_iterator iter;
  48   /* Has the iterator been initialized flag.  */
  49   int initialized_p;
  50   /* Pointer back to the original source block object.  Needed to
  51      check if the block is still valid, and has not been invalidated
  52      when an object file has been freed.  */
  53   struct blpy_block_object *source;
  54 } block_syms_iterator_object;
  55
  56 /* Require a valid block.  All access to block_object->block should be
  57    gated by this call.  */
  58 #define BLPY_REQUIRE_VALID(block_obj, block)            \
  59   do {                                                  \
  60     block = block_object_to_block (block_obj);          \
  61     if (block == NULL)                                  \
  62       {                                                 \
  63         PyErr_SetString (PyExc_RuntimeError,            \
  64                          _("Block is invalid."));       \
  65         return NULL;                                    \
  66       }                                                 \
  67   } while (0)
  68
  69 /* Require a valid block.  This macro is called during block iterator
  70    creation, and at each next call.  */
  71 #define BLPY_ITER_REQUIRE_VALID(block_obj)                              \
  72   do {                                                                  \
  73     if (block_obj->block == NULL)                                       \
  74       {                                                                 \
  75         PyErr_SetString (PyExc_RuntimeError,                            \
  76                          _("Source block for iterator is invalid."));   \
  77         return NULL;                                                    \
  78       }                                                                 \
  79   } while (0)
  80
  81 static PyTypeObject block_syms_iterator_object_type;
  82 static const struct objfile_data *blpy_objfile_data_key;
  83
  84 static PyObject *
  85 blpy_iter (PyObject *self)
  86 {
  87   block_syms_iterator_object *block_iter_obj;
  88   struct block *block = NULL;
  89
  90   BLPY_REQUIRE_VALID (self, block);
  91
  92   block_iter_obj = PyObject_New (block_syms_iterator_object,
  93                                  &block_syms_iterator_object_type);
  94   if (block_iter_obj == NULL)
  95       return NULL;
  96
  97   block_iter_obj->dict = BLOCK_DICT (block);
  98   block_iter_obj->initialized_p = 0;
  99   Py_INCREF (self);
 100   block_iter_obj->source = (block_object *) self;
 101
 102   return (PyObject *) block_iter_obj;
 103 }
 104
 105 static PyObject *
 106 blpy_get_start (PyObject *self, void *closure)
 107 {
 108   struct block *block = NULL;
 109
 110   BLPY_REQUIRE_VALID (self, block);
 111
 112   return PyLong_FromUnsignedLongLong (BLOCK_START (block));
 113 }
 114
 115 static PyObject *
 116 blpy_get_end (PyObject *self, void *closure)
 117 {
 118   struct block *block = NULL;
 119
 120   BLPY_REQUIRE_VALID (self, block);
 121
 122   return PyLong_FromUnsignedLongLong (BLOCK_END (block));
 123 }
 124
 125 static PyObject *
 126 blpy_get_function (PyObject *self, void *closure)
 127 {
 128   struct symbol *sym;
 129   struct block *block = NULL;
 130
 131   BLPY_REQUIRE_VALID (self, block);
 132
 133   sym = BLOCK_FUNCTION (block);
 134   if (sym)
 135     return symbol_to_symbol_object (sym);
 136
 137   Py_RETURN_NONE;
 138 }
 139
 140 static PyObject *
 141 blpy_get_superblock (PyObject *self, void *closure)
 142 {
 143   struct block *block = NULL;
 144   struct block *super_block = NULL;
 145   block_object *self_obj  = (block_object *) self;
 146
 147   BLPY_REQUIRE_VALID (self, block);
 148
 149   super_block = BLOCK_SUPERBLOCK (block);
 150   if (super_block)
 151     return block_to_block_object (super_block, self_obj->objfile);
 152
 153   Py_RETURN_NONE;
 154 }
 155
 156 static void
 157 blpy_dealloc (PyObject *obj)
 158 {
 159   block_object *block = (block_object *) obj;
 160
 161   if (block->prev)
 162     block->prev->next = block->next;
 163   else if (block->objfile)
 164     {
 165       set_objfile_data (block->objfile, blpy_objfile_data_key,
 166                         block->next);
 167     }
 168   if (block->next)
 169     block->next->prev = block->prev;
 170   block->block = NULL;
 171 }
 172
 173 /* Given a block, and a block_object that has previously been
 174    allocated and initialized, populate the block_object with the
 175    struct block data.  Also, register the block_object life-cycle
 176    with the life-cycle of the the object file associated with this
 177    block, if needed.  */
 178 static void
 179 set_block (block_object *obj, struct block *block,
 180            struct objfile *objfile)
 181 {
 182   obj->block = block;
 183   obj->prev = NULL;
 184   if (objfile)
 185     {
 186       obj->objfile = objfile;
 187       obj->next = objfile_data (objfile, blpy_objfile_data_key);
 188       if (obj->next)
 189         obj->next->prev = obj;
 190       set_objfile_data (objfile, blpy_objfile_data_key, obj);
 191     }
 192   else
 193     obj->next = NULL;
 194 }
 195
 196 /* Create a new block object (gdb.Block) that encapsulates the struct
 197    block object from GDB.  */
 198 PyObject *
 199 block_to_block_object (struct block *block, struct objfile *objfile)
 200 {
 201   block_object *block_obj;
 202
 203   block_obj = PyObject_New (block_object, &block_object_type);
 204   if (block_obj)
 205     set_block (block_obj, block, objfile);
 206
 207   return (PyObject *) block_obj;
 208 }
 209
 210 /* Return struct block reference that is wrapped by this object.  */
 211 struct block *
 212 block_object_to_block (PyObject *obj)
 213 {
 214   if (! PyObject_TypeCheck (obj, &block_object_type))
 215     return NULL;
 216   return ((block_object *) obj)->block;
 217 }
 218
 219 /* Return a reference to the block iterator.  */
 220 static PyObject *
 221 blpy_block_syms_iter (PyObject *self)
 222 {
 223   block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) self;
 224
 225   BLPY_ITER_REQUIRE_VALID (iter_obj->source);
 226
 227   Py_INCREF (self);
 228   return self;
 229 }
 230
 231 /* Return the next symbol in the iteration through the block's
 232    dictionary.  */
 233 static PyObject *
 234 blpy_block_syms_iternext (PyObject *self)
 235 {
 236   block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) self;
 237   struct symbol *sym;
 238
 239   BLPY_ITER_REQUIRE_VALID (iter_obj->source);
 240
 241   if (!iter_obj->initialized_p)
 242     {
 243       sym = dict_iterator_first (iter_obj->dict,  &(iter_obj->iter));
 244       iter_obj->initialized_p = 1;
 245     }
 246   else
 247     sym = dict_iterator_next (&(iter_obj->iter));
 248
 249   if (sym == NULL)
 250     {
 251       PyErr_SetString (PyExc_StopIteration, _("Symbol is null."));
 252       return NULL;
 253     }
 254
 255   return symbol_to_symbol_object (sym);
 256 }
 257
 258 static void
 259 blpy_block_syms_dealloc (PyObject *obj)
 260 {
 261   block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) obj;
 262   Py_XDECREF (iter_obj->source);
 263 }
 264
 265 /* Return the innermost lexical block containing the specified pc value,
 266    or 0 if there is none.  */
 267 PyObject *
 268 gdbpy_block_for_pc (PyObject *self, PyObject *args)
 269 {
 270   unsigned PY_LONG_LONG pc;
 271   struct block *block;
 272   struct obj_section *section;
 273   struct symtab *symtab;
 274
 275   if (!PyArg_ParseTuple (args, "K", &pc))
 276     return NULL;
 277
 278   section = find_pc_mapped_section (pc);
 279   symtab = find_pc_sect_symtab (pc, section);
 280   if (!symtab || symtab->objfile == NULL)
 281     {
 282       PyErr_SetString (PyExc_RuntimeError,
 283                        _("Cannot locate object file for block."));
 284       return NULL;
 285     }
 286
 287   block = block_for_pc (pc);
 288   if (block)
 289     return block_to_block_object (block, symtab->objfile);
 290
 291   Py_RETURN_NONE;
 292 }
 293
 294 /* This function is called when an objfile is about to be freed.
 295    Invalidate the block as further actions on the block would result
 296    in bad data.  All access to obj->symbol should be gated by
 297    BLPY_REQUIRE_VALID which will raise an exception on invalid
 298    blocks.  */
 299 static void
 300 del_objfile_blocks (struct objfile *objfile, void *datum)
 301 {
 302   block_object *obj = datum;
 303   while (obj)
 304     {
 305       block_object *next = obj->next;
 306
 307       obj->block = NULL;
 308       obj->objfile = NULL;
 309       obj->next = NULL;
 310       obj->prev = NULL;
 311
 312       obj = next;
 313     }
 314 }
 315
 316 void
 317 gdbpy_initialize_blocks (void)
 318 {
 319   block_object_type.tp_new = PyType_GenericNew;
 320   if (PyType_Ready (&block_object_type) < 0)
 321     return;
 322
 323   block_syms_iterator_object_type.tp_new = PyType_GenericNew;
 324   if (PyType_Ready (&block_syms_iterator_object_type) < 0)
 325     return;
 326
 327   /* Register an objfile "free" callback so we can properly
 328      invalidate blocks when an object file is about to be
 329      deleted.  */
 330   blpy_objfile_data_key
 331     = register_objfile_data_with_cleanup (NULL, del_objfile_blocks);
 332
 333   Py_INCREF (&block_object_type);
 334   PyModule_AddObject (gdb_module, "Block", (PyObject *) &block_object_type);
 335
 336   Py_INCREF (&block_syms_iterator_object_type);
 337   PyModule_AddObject (gdb_module, "BlockIterator",
 338                       (PyObject *) &block_syms_iterator_object_type);
 339 }
 340
 341 \f
 342
 343 static PyGetSetDef block_object_getset[] = {
 344   { "start", blpy_get_start, NULL, "Start address of the block.", NULL },
 345   { "end", blpy_get_end, NULL, "End address of the block.", NULL },
 346   { "function", blpy_get_function, NULL,
 347     "Symbol that names the block, or None.", NULL },
 348   { "superblock", blpy_get_superblock, NULL,
 349     "Block containing the block, or None.", NULL },
 350   { NULL }  /* Sentinel */
 351 };
 352
 353 PyTypeObject block_object_type = {
 354   PyObject_HEAD_INIT (NULL)
 355   0,                              /*ob_size*/
 356   "gdb.Block",                    /*tp_name*/
 357   sizeof (block_object),          /*tp_basicsize*/
 358   0,                              /*tp_itemsize*/
 359   blpy_dealloc,                   /*tp_dealloc*/
 360   0,                              /*tp_print*/
 361   0,                              /*tp_getattr*/
 362   0,                              /*tp_setattr*/
 363   0,                              /*tp_compare*/
 364   0,                              /*tp_repr*/
 365   0,                              /*tp_as_number*/
 366   0,                              /*tp_as_sequence*/
 367   0,                              /*tp_as_mapping*/
 368   0,                              /*tp_hash */
 369   0,                              /*tp_call*/
 370   0,                              /*tp_str*/
 371   0,                              /*tp_getattro*/
 372   0,                              /*tp_setattro*/
 373   0,                              /*tp_as_buffer*/
 374   Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,  /*tp_flags*/
 375   "GDB block object",             /* tp_doc */
 376   0,                              /* tp_traverse */
 377   0,                              /* tp_clear */
 378   0,                              /* tp_richcompare */
 379   0,                              /* tp_weaklistoffset */
 380   blpy_iter,                      /* tp_iter */
 381   0,                              /* tp_iternext */
 382   0,                              /* tp_methods */
 383   0,                              /* tp_members */
 384   block_object_getset             /* tp_getset */
 385 };
 386
 387 static PyTypeObject block_syms_iterator_object_type = {
 388   PyObject_HEAD_INIT (NULL)
 389   0,                              /*ob_size*/
 390   "gdb.BlockIterator",            /*tp_name*/
 391   sizeof (block_syms_iterator_object),        /*tp_basicsize*/
 392   0,                              /*tp_itemsize*/
 393   blpy_block_syms_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   0,                              /*tp_str*/
 405   0,                              /*tp_getattro*/
 406   0,                              /*tp_setattro*/
 407   0,                              /*tp_as_buffer*/
 408   Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,  /*tp_flags*/
 409   "GDB block syms iterator object",           /*tp_doc */
 410   0,                              /*tp_traverse */
 411   0,                              /*tp_clear */
 412   0,                              /*tp_richcompare */
 413   0,                              /*tp_weaklistoffset */
 414   blpy_block_syms_iter,           /*tp_iter */
 415   blpy_block_syms_iternext,       /*tp_iternext */
 416   0                               /*tp_methods */
 417 };