gdb/python/py-value.c

   1 /* Python interface to values.
   2
   3    Copyright (C) 2008, 2009 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 "gdb_assert.h"
  22 #include "charset.h"
  23 #include "value.h"
  24 #include "exceptions.h"
  25 #include "language.h"
  26 #include "dfp.h"
  27 #include "valprint.h"
  28
  29 #ifdef HAVE_PYTHON
  30
  31 #include "python-internal.h"
  32
  33 /* Even though Python scalar types directly map to host types, we use
  34    target types here to remain consistent with the the values system in
  35    GDB (which uses target arithmetic).  */
  36
  37 /* Python's integer type corresponds to C's long type.  */
  38 #define builtin_type_pyint builtin_type (python_gdbarch)->builtin_long
  39
  40 /* Python's float type corresponds to C's double type.  */
  41 #define builtin_type_pyfloat builtin_type (python_gdbarch)->builtin_double
  42
  43 /* Python's long type corresponds to C's long long type.  */
  44 #define builtin_type_pylong builtin_type (python_gdbarch)->builtin_long_long
  45
  46 #define builtin_type_pybool \
  47   language_bool_type (python_language, python_gdbarch)
  48
  49 #define builtin_type_pychar \
  50   language_string_char_type (python_language, python_gdbarch)
  51
  52 typedef struct value_object {
  53   PyObject_HEAD
  54   struct value_object *next;
  55   struct value_object *prev;
  56   struct value *value;
  57   PyObject *address;
  58   PyObject *type;
  59 } value_object;
  60
  61 /* List of all values which are currently exposed to Python. It is
  62    maintained so that when an objfile is discarded, preserve_values
  63    can copy the values' types if needed.  */
  64 /* This variable is unnecessarily initialized to NULL in order to
  65    work around a linker bug on MacOS.  */
  66 static value_object *values_in_python = NULL;
  67
  68 /* Called by the Python interpreter when deallocating a value object.  */
  69 static void
  70 valpy_dealloc (PyObject *obj)
  71 {
  72   value_object *self = (value_object *) obj;
  73
  74   /* Remove SELF from the global list.  */
  75   if (self->prev)
  76     self->prev->next = self->next;
  77   else
  78     {
  79       gdb_assert (values_in_python == self);
  80       values_in_python = self->next;
  81     }
  82   if (self->next)
  83     self->next->prev = self->prev;
  84
  85   value_free (self->value);
  86
  87   if (self->address)
  88     /* Use braces to appease gcc warning.  *sigh*  */
  89     {
  90       Py_DECREF (self->address);
  91     }
  92
  93   if (self->type)
  94     {
  95       Py_DECREF (self->type);
  96     }
  97
  98   self->ob_type->tp_free (self);
  99 }
 100
 101 /* Helper to push a Value object on the global list.  */
 102 static void
 103 note_value (value_object *value_obj)
 104 {
 105   value_obj->next = values_in_python;
 106   if (value_obj->next)
 107     value_obj->next->prev = value_obj;
 108   value_obj->prev = NULL;
 109   values_in_python = value_obj;
 110 }
 111
 112 /* Called when a new gdb.Value object needs to be allocated.  */
 113 static PyObject *
 114 valpy_new (PyTypeObject *subtype, PyObject *args, PyObject *keywords)
 115 {
 116   struct value *value = NULL;   /* Initialize to appease gcc warning.  */
 117   value_object *value_obj;
 118
 119   if (PyTuple_Size (args) != 1)
 120     {
 121       PyErr_SetString (PyExc_TypeError, _("Value object creation takes only "
 122                                           "1 argument"));
 123       return NULL;
 124     }
 125
 126   value_obj = (value_object *) subtype->tp_alloc (subtype, 1);
 127   if (value_obj == NULL)
 128     {
 129       PyErr_SetString (PyExc_MemoryError, _("Could not allocate memory to "
 130                                             "create Value object."));
 131       return NULL;
 132     }
 133
 134   value = convert_value_from_python (PyTuple_GetItem (args, 0));
 135   if (value == NULL)
 136     {
 137       subtype->tp_free (value_obj);
 138       return NULL;
 139     }
 140
 141   value_obj->value = value;
 142   value_incref (value);
 143   value_obj->address = NULL;
 144   value_obj->type = NULL;
 145   note_value (value_obj);
 146
 147   return (PyObject *) value_obj;
 148 }
 149
 150 /* Iterate over all the Value objects, calling preserve_one_value on
 151    each.  */
 152 void
 153 preserve_python_values (struct objfile *objfile, htab_t copied_types)
 154 {
 155   value_object *iter;
 156
 157   for (iter = values_in_python; iter; iter = iter->next)
 158     preserve_one_value (iter->value, objfile, copied_types);
 159 }
 160
 161 /* Given a value of a pointer type, apply the C unary * operator to it.  */
 162 static PyObject *
 163 valpy_dereference (PyObject *self, PyObject *args)
 164 {
 165   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 166   volatile struct gdb_exception except;
 167
 168   TRY_CATCH (except, RETURN_MASK_ALL)
 169     {
 170       res_val = value_ind (((value_object *) self)->value);
 171     }
 172   GDB_PY_HANDLE_EXCEPTION (except);
 173
 174   return value_to_value_object (res_val);
 175 }
 176
 177 /* Return "&value".  */
 178 static PyObject *
 179 valpy_get_address (PyObject *self, void *closure)
 180 {
 181   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 182   value_object *val_obj = (value_object *) self;
 183   volatile struct gdb_exception except;
 184
 185   if (!val_obj->address)
 186     {
 187       TRY_CATCH (except, RETURN_MASK_ALL)
 188         {
 189           res_val = value_addr (val_obj->value);
 190         }
 191       if (except.reason < 0)
 192         {
 193           val_obj->address = Py_None;
 194           Py_INCREF (Py_None);
 195         }
 196       else
 197         val_obj->address = value_to_value_object (res_val);
 198     }
 199
 200   Py_INCREF (val_obj->address);
 201
 202   return val_obj->address;
 203 }
 204
 205 /* Return type of the value.  */
 206 static PyObject *
 207 valpy_get_type (PyObject *self, void *closure)
 208 {
 209   value_object *obj = (value_object *) self;
 210   if (!obj->type)
 211     {
 212       obj->type = type_to_type_object (value_type (obj->value));
 213       if (!obj->type)
 214         {
 215           obj->type = Py_None;
 216           Py_INCREF (obj->type);
 217         }
 218     }
 219   Py_INCREF (obj->type);
 220   return obj->type;
 221 }
 222
 223 /* Implementation of gdb.Value.string ([encoding] [, errors]
 224    [, length]) -> string.  Return Unicode string with value contents.
 225    If ENCODING is not given, the string is assumed to be encoded in
 226    the target's charset.  If LENGTH is provided, only fetch string to
 227    the length provided.  */
 228
 229 static PyObject *
 230 valpy_string (PyObject *self, PyObject *args, PyObject *kw)
 231 {
 232   int length = -1, ret = 0;
 233   gdb_byte *buffer;
 234   struct value *value = ((value_object *) self)->value;
 235   volatile struct gdb_exception except;
 236   PyObject *unicode;
 237   const char *encoding = NULL;
 238   const char *errors = NULL;
 239   const char *user_encoding = NULL;
 240   const char *la_encoding = NULL;
 241   struct type *char_type;
 242   static char *keywords[] = { "encoding", "errors", "length", NULL };
 243
 244   if (!PyArg_ParseTupleAndKeywords (args, kw, "|ssi", keywords,
 245                                     &user_encoding, &errors, &length))
 246     return NULL;
 247
 248   TRY_CATCH (except, RETURN_MASK_ALL)
 249     {
 250       LA_GET_STRING (value, &buffer, &length, &char_type, &la_encoding);
 251     }
 252   GDB_PY_HANDLE_EXCEPTION (except);
 253
 254   encoding = (user_encoding && *user_encoding) ? user_encoding : la_encoding;
 255   unicode = PyUnicode_Decode (buffer, length * TYPE_LENGTH (char_type),
 256                               encoding, errors);
 257   xfree (buffer);
 258
 259   return unicode;
 260 }
 261
 262 /* Cast a value to a given type.  */
 263 static PyObject *
 264 valpy_cast (PyObject *self, PyObject *args)
 265 {
 266   PyObject *type_obj;
 267   struct type *type;
 268   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 269   volatile struct gdb_exception except;
 270
 271   if (! PyArg_ParseTuple (args, "O", &type_obj))
 272     return NULL;
 273
 274   type = type_object_to_type (type_obj);
 275   if (! type)
 276     {
 277       PyErr_SetString (PyExc_RuntimeError, "argument must be a Type");
 278       return NULL;
 279     }
 280
 281   TRY_CATCH (except, RETURN_MASK_ALL)
 282     {
 283       res_val = value_cast (type, ((value_object *) self)->value);
 284     }
 285   GDB_PY_HANDLE_EXCEPTION (except);
 286
 287   return value_to_value_object (res_val);
 288 }
 289
 290 static Py_ssize_t
 291 valpy_length (PyObject *self)
 292 {
 293   /* We don't support getting the number of elements in a struct / class.  */
 294   PyErr_SetString (PyExc_NotImplementedError,
 295                    "Invalid operation on gdb.Value.");
 296   return -1;
 297 }
 298
 299 /* Given string name of an element inside structure, return its value
 300    object.  */
 301 static PyObject *
 302 valpy_getitem (PyObject *self, PyObject *key)
 303 {
 304   value_object *self_value = (value_object *) self;
 305   char *field = NULL;
 306   struct value *res_val = NULL;
 307   volatile struct gdb_exception except;
 308
 309   if (gdbpy_is_string (key))
 310     {
 311       field = python_string_to_host_string (key);
 312       if (field == NULL)
 313         return NULL;
 314     }
 315
 316   TRY_CATCH (except, RETURN_MASK_ALL)
 317     {
 318       struct value *tmp = self_value->value;
 319
 320       if (field)
 321         res_val = value_struct_elt (&tmp, NULL, field, 0, NULL);
 322       else
 323         {
 324           /* Assume we are attempting an array access, and let the
 325              value code throw an exception if the index has an invalid
 326              type.  */
 327           struct value *idx = convert_value_from_python (key);
 328           if (idx != NULL)
 329             {
 330               /* Check the value's type is something that can be accessed via
 331                  a subscript.  */
 332               struct type *type;
 333               tmp = coerce_ref (tmp);
 334               type = check_typedef (value_type (tmp));
 335               if (TYPE_CODE (type) != TYPE_CODE_ARRAY
 336                   && TYPE_CODE (type) != TYPE_CODE_PTR)
 337                   error( _("Cannot subscript requested type"));
 338               else
 339                 res_val = value_subscript (tmp, value_as_long (idx));
 340             }
 341         }
 342     }
 343
 344   xfree (field);
 345   GDB_PY_HANDLE_EXCEPTION (except);
 346
 347   return res_val ? value_to_value_object (res_val) : NULL;
 348 }
 349
 350 static int
 351 valpy_setitem (PyObject *self, PyObject *key, PyObject *value)
 352 {
 353   PyErr_Format (PyExc_NotImplementedError,
 354                 _("Setting of struct elements is not currently supported."));
 355   return -1;
 356 }
 357
 358 /* Called by the Python interpreter to obtain string representation
 359    of the object.  */
 360 static PyObject *
 361 valpy_str (PyObject *self)
 362 {
 363   char *s = NULL;
 364   struct ui_file *stb;
 365   struct cleanup *old_chain;
 366   PyObject *result;
 367   struct value_print_options opts;
 368   volatile struct gdb_exception except;
 369
 370   get_user_print_options (&opts);
 371   opts.deref_ref = 0;
 372
 373   stb = mem_fileopen ();
 374   old_chain = make_cleanup_ui_file_delete (stb);
 375
 376   TRY_CATCH (except, RETURN_MASK_ALL)
 377     {
 378       common_val_print (((value_object *) self)->value, stb, 0,
 379                         &opts, python_language);
 380       s = ui_file_xstrdup (stb, NULL);
 381     }
 382   GDB_PY_HANDLE_EXCEPTION (except);
 383
 384   do_cleanups (old_chain);
 385
 386   result = PyUnicode_Decode (s, strlen (s), host_charset (), NULL);
 387   xfree (s);
 388
 389   return result;
 390 }
 391
 392 /* Implements gdb.Value.is_optimized_out.  */
 393 static PyObject *
 394 valpy_get_is_optimized_out (PyObject *self, void *closure)
 395 {
 396   struct value *value = ((value_object *) self)->value;
 397
 398   if (value_optimized_out (value))
 399     Py_RETURN_TRUE;
 400
 401   Py_RETURN_FALSE;
 402 }
 403
 404 enum valpy_opcode
 405 {
 406   VALPY_ADD,
 407   VALPY_SUB,
 408   VALPY_MUL,
 409   VALPY_DIV,
 410   VALPY_REM,
 411   VALPY_POW,
 412   VALPY_LSH,
 413   VALPY_RSH,
 414   VALPY_BITAND,
 415   VALPY_BITOR,
 416   VALPY_BITXOR
 417 };
 418
 419 /* If TYPE is a reference, return the target; otherwise return TYPE.  */
 420 #define STRIP_REFERENCE(TYPE) \
 421   ((TYPE_CODE (TYPE) == TYPE_CODE_REF) ? (TYPE_TARGET_TYPE (TYPE)) : (TYPE))
 422
 423 /* Returns a value object which is the result of applying the operation
 424    specified by OPCODE to the given arguments.  */
 425 static PyObject *
 426 valpy_binop (enum valpy_opcode opcode, PyObject *self, PyObject *other)
 427 {
 428   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 429   volatile struct gdb_exception except;
 430
 431   TRY_CATCH (except, RETURN_MASK_ALL)
 432     {
 433       struct value *arg1, *arg2;
 434
 435       /* If the gdb.Value object is the second operand, then it will be passed
 436          to us as the OTHER argument, and SELF will be an entirely different
 437          kind of object, altogether.  Because of this, we can't assume self is
 438          a gdb.Value object and need to convert it from python as well.  */
 439       arg1 = convert_value_from_python (self);
 440       if (arg1 == NULL)
 441         break;
 442
 443       arg2 = convert_value_from_python (other);
 444       if (arg2 == NULL)
 445         break;
 446
 447       switch (opcode)
 448         {
 449         case VALPY_ADD:
 450           {
 451             struct type *ltype = value_type (arg1);
 452             struct type *rtype = value_type (arg2);
 453
 454             CHECK_TYPEDEF (ltype);
 455             ltype = STRIP_REFERENCE (ltype);
 456             CHECK_TYPEDEF (rtype);
 457             rtype = STRIP_REFERENCE (rtype);
 458
 459             if (TYPE_CODE (ltype) == TYPE_CODE_PTR
 460                 && is_integral_type (rtype))
 461               res_val = value_ptradd (arg1, value_as_long (arg2));
 462             else if (TYPE_CODE (rtype) == TYPE_CODE_PTR
 463                      && is_integral_type (ltype))
 464               res_val = value_ptradd (arg2, value_as_long (arg1));
 465             else
 466               res_val = value_binop (arg1, arg2, BINOP_ADD);
 467           }
 468           break;
 469         case VALPY_SUB:
 470           {
 471             struct type *ltype = value_type (arg1);
 472             struct type *rtype = value_type (arg2);
 473
 474             CHECK_TYPEDEF (ltype);
 475             ltype = STRIP_REFERENCE (ltype);
 476             CHECK_TYPEDEF (rtype);
 477             rtype = STRIP_REFERENCE (rtype);
 478
 479             if (TYPE_CODE (ltype) == TYPE_CODE_PTR
 480                 && TYPE_CODE (rtype) == TYPE_CODE_PTR)
 481               /* A ptrdiff_t for the target would be preferable here.  */
 482               res_val = value_from_longest (builtin_type_pyint,
 483                                             value_ptrdiff (arg1, arg2));
 484             else if (TYPE_CODE (ltype) == TYPE_CODE_PTR
 485                      && is_integral_type (rtype))
 486               res_val = value_ptradd (arg1, - value_as_long (arg2));
 487             else
 488               res_val = value_binop (arg1, arg2, BINOP_SUB);
 489           }
 490           break;
 491         case VALPY_MUL:
 492           res_val = value_binop (arg1, arg2, BINOP_MUL);
 493           break;
 494         case VALPY_DIV:
 495           res_val = value_binop (arg1, arg2, BINOP_DIV);
 496           break;
 497         case VALPY_REM:
 498           res_val = value_binop (arg1, arg2, BINOP_REM);
 499           break;
 500         case VALPY_POW:
 501           res_val = value_binop (arg1, arg2, BINOP_EXP);
 502           break;
 503         case VALPY_LSH:
 504           res_val = value_binop (arg1, arg2, BINOP_LSH);
 505           break;
 506         case VALPY_RSH:
 507           res_val = value_binop (arg1, arg2, BINOP_RSH);
 508           break;
 509         case VALPY_BITAND:
 510           res_val = value_binop (arg1, arg2, BINOP_BITWISE_AND);
 511           break;
 512         case VALPY_BITOR:
 513           res_val = value_binop (arg1, arg2, BINOP_BITWISE_IOR);
 514           break;
 515         case VALPY_BITXOR:
 516           res_val = value_binop (arg1, arg2, BINOP_BITWISE_XOR);
 517           break;
 518         }
 519     }
 520   GDB_PY_HANDLE_EXCEPTION (except);
 521
 522   return res_val ? value_to_value_object (res_val) : NULL;
 523 }
 524
 525 static PyObject *
 526 valpy_add (PyObject *self, PyObject *other)
 527 {
 528   return valpy_binop (VALPY_ADD, self, other);
 529 }
 530
 531 static PyObject *
 532 valpy_subtract (PyObject *self, PyObject *other)
 533 {
 534   return valpy_binop (VALPY_SUB, self, other);
 535 }
 536
 537 static PyObject *
 538 valpy_multiply (PyObject *self, PyObject *other)
 539 {
 540   return valpy_binop (VALPY_MUL, self, other);
 541 }
 542
 543 static PyObject *
 544 valpy_divide (PyObject *self, PyObject *other)
 545 {
 546   return valpy_binop (VALPY_DIV, self, other);
 547 }
 548
 549 static PyObject *
 550 valpy_remainder (PyObject *self, PyObject *other)
 551 {
 552   return valpy_binop (VALPY_REM, self, other);
 553 }
 554
 555 static PyObject *
 556 valpy_power (PyObject *self, PyObject *other, PyObject *unused)
 557 {
 558   /* We don't support the ternary form of pow.  I don't know how to express
 559      that, so let's just throw NotImplementedError to at least do something
 560      about it.  */
 561   if (unused != Py_None)
 562     {
 563       PyErr_SetString (PyExc_NotImplementedError,
 564                        "Invalid operation on gdb.Value.");
 565       return NULL;
 566     }
 567
 568   return valpy_binop (VALPY_POW, self, other);
 569 }
 570
 571 static PyObject *
 572 valpy_negative (PyObject *self)
 573 {
 574   struct value *val = NULL;
 575   volatile struct gdb_exception except;
 576
 577   TRY_CATCH (except, RETURN_MASK_ALL)
 578     {
 579       val = value_neg (((value_object *) self)->value);
 580     }
 581   GDB_PY_HANDLE_EXCEPTION (except);
 582
 583   return value_to_value_object (val);
 584 }
 585
 586 static PyObject *
 587 valpy_positive (PyObject *self)
 588 {
 589   return value_to_value_object (((value_object *) self)->value);
 590 }
 591
 592 static PyObject *
 593 valpy_absolute (PyObject *self)
 594 {
 595   struct value *value = ((value_object *) self)->value;
 596   if (value_less (value, value_zero (value_type (value), not_lval)))
 597     return valpy_negative (self);
 598   else
 599     return valpy_positive (self);
 600 }
 601
 602 /* Implements boolean evaluation of gdb.Value.  */
 603 static int
 604 valpy_nonzero (PyObject *self)
 605 {
 606   value_object *self_value = (value_object *) self;
 607   struct type *type;
 608
 609   type = check_typedef (value_type (self_value->value));
 610
 611   if (is_integral_type (type) || TYPE_CODE (type) == TYPE_CODE_PTR)
 612     return !!value_as_long (self_value->value);
 613   else if (TYPE_CODE (type) == TYPE_CODE_FLT)
 614     return value_as_double (self_value->value) != 0;
 615   else if (TYPE_CODE (type) == TYPE_CODE_DECFLOAT)
 616     return !decimal_is_zero (value_contents (self_value->value),
 617                              TYPE_LENGTH (type),
 618                              gdbarch_byte_order (get_type_arch (type)));
 619   else
 620     {
 621       PyErr_SetString (PyExc_TypeError, _("Attempted truth testing on invalid "
 622                                           "gdb.Value type."));
 623       return 0;
 624     }
 625 }
 626
 627 /* Implements ~ for value objects.  */
 628 static PyObject *
 629 valpy_invert (PyObject *self)
 630 {
 631   struct value *val = NULL;
 632   volatile struct gdb_exception except;
 633
 634   TRY_CATCH (except, RETURN_MASK_ALL)
 635     {
 636       val = value_complement (((value_object *) self)->value);
 637     }
 638   GDB_PY_HANDLE_EXCEPTION (except);
 639
 640   return value_to_value_object (val);
 641 }
 642
 643 /* Implements left shift for value objects.  */
 644 static PyObject *
 645 valpy_lsh (PyObject *self, PyObject *other)
 646 {
 647   return valpy_binop (VALPY_LSH, self, other);
 648 }
 649
 650 /* Implements right shift for value objects.  */
 651 static PyObject *
 652 valpy_rsh (PyObject *self, PyObject *other)
 653 {
 654   return valpy_binop (VALPY_RSH, self, other);
 655 }
 656
 657 /* Implements bitwise and for value objects.  */
 658 static PyObject *
 659 valpy_and (PyObject *self, PyObject *other)
 660 {
 661   return valpy_binop (VALPY_BITAND, self, other);
 662 }
 663
 664 /* Implements bitwise or for value objects.  */
 665 static PyObject *
 666 valpy_or (PyObject *self, PyObject *other)
 667 {
 668   return valpy_binop (VALPY_BITOR, self, other);
 669 }
 670
 671 /* Implements bitwise xor for value objects.  */
 672 static PyObject *
 673 valpy_xor (PyObject *self, PyObject *other)
 674 {
 675   return valpy_binop (VALPY_BITXOR, self, other);
 676 }
 677
 678 /* Implements comparison operations for value objects.  */
 679 static PyObject *
 680 valpy_richcompare (PyObject *self, PyObject *other, int op)
 681 {
 682   int result = 0;
 683   struct value *value_other;
 684   volatile struct gdb_exception except;
 685
 686   if (other == Py_None)
 687     /* Comparing with None is special.  From what I can tell, in Python
 688        None is smaller than anything else.  */
 689     switch (op) {
 690       case Py_LT:
 691       case Py_LE:
 692       case Py_EQ:
 693         Py_RETURN_FALSE;
 694       case Py_NE:
 695       case Py_GT:
 696       case Py_GE:
 697         Py_RETURN_TRUE;
 698       default:
 699         /* Can't happen.  */
 700         PyErr_SetString (PyExc_NotImplementedError,
 701                          "Invalid operation on gdb.Value.");
 702         return NULL;
 703     }
 704
 705   TRY_CATCH (except, RETURN_MASK_ALL)
 706     {
 707       value_other = convert_value_from_python (other);
 708       if (value_other == NULL)
 709         {
 710           result = -1;
 711           break;
 712         }
 713
 714       switch (op) {
 715         case Py_LT:
 716           result = value_less (((value_object *) self)->value, value_other);
 717           break;
 718         case Py_LE:
 719           result = value_less (((value_object *) self)->value, value_other)
 720             || value_equal (((value_object *) self)->value, value_other);
 721           break;
 722         case Py_EQ:
 723           result = value_equal (((value_object *) self)->value, value_other);
 724           break;
 725         case Py_NE:
 726           result = !value_equal (((value_object *) self)->value, value_other);
 727           break;
 728         case Py_GT:
 729           result = value_less (value_other, ((value_object *) self)->value);
 730           break;
 731         case Py_GE:
 732           result = value_less (value_other, ((value_object *) self)->value)
 733             || value_equal (((value_object *) self)->value, value_other);
 734           break;
 735         default:
 736           /* Can't happen.  */
 737           PyErr_SetString (PyExc_NotImplementedError,
 738                            "Invalid operation on gdb.Value.");
 739           result = -1;
 740           break;
 741       }
 742     }
 743   GDB_PY_HANDLE_EXCEPTION (except);
 744
 745   /* In this case, the Python exception has already been set.  */
 746   if (result < 0)
 747     return NULL;
 748
 749   if (result == 1)
 750     Py_RETURN_TRUE;
 751
 752   Py_RETURN_FALSE;
 753 }
 754
 755 /* Helper function to determine if a type is "int-like".  */
 756 static int
 757 is_intlike (struct type *type, int ptr_ok)
 758 {
 759   CHECK_TYPEDEF (type);
 760   return (TYPE_CODE (type) == TYPE_CODE_INT
 761           || TYPE_CODE (type) == TYPE_CODE_ENUM
 762           || TYPE_CODE (type) == TYPE_CODE_BOOL
 763           || TYPE_CODE (type) == TYPE_CODE_CHAR
 764           || (ptr_ok && TYPE_CODE (type) == TYPE_CODE_PTR));
 765 }
 766
 767 /* Implements conversion to int.  */
 768 static PyObject *
 769 valpy_int (PyObject *self)
 770 {
 771   struct value *value = ((value_object *) self)->value;
 772   struct type *type = value_type (value);
 773   LONGEST l = 0;
 774   volatile struct gdb_exception except;
 775
 776   CHECK_TYPEDEF (type);
 777   if (!is_intlike (type, 0))
 778     {
 779       PyErr_SetString (PyExc_RuntimeError, "cannot convert value to int");
 780       return NULL;
 781     }
 782
 783   TRY_CATCH (except, RETURN_MASK_ALL)
 784     {
 785       l = value_as_long (value);
 786     }
 787   GDB_PY_HANDLE_EXCEPTION (except);
 788
 789 #ifdef HAVE_LONG_LONG           /* Defined by Python.  */
 790   /* If we have 'long long', and the value overflows a 'long', use a
 791      Python Long; otherwise use a Python Int.  */
 792   if (sizeof (l) > sizeof (long) && (l > PyInt_GetMax ()
 793                                      || l < (- (LONGEST) PyInt_GetMax ()) - 1))
 794     return PyLong_FromLongLong (l);
 795 #endif
 796   return PyInt_FromLong (l);
 797 }
 798
 799 /* Implements conversion to long.  */
 800 static PyObject *
 801 valpy_long (PyObject *self)
 802 {
 803   struct value *value = ((value_object *) self)->value;
 804   struct type *type = value_type (value);
 805   LONGEST l = 0;
 806   volatile struct gdb_exception except;
 807
 808   if (!is_intlike (type, 1))
 809     {
 810       PyErr_SetString (PyExc_RuntimeError, "cannot convert value to long");
 811       return NULL;
 812     }
 813
 814   TRY_CATCH (except, RETURN_MASK_ALL)
 815     {
 816       l = value_as_long (value);
 817     }
 818   GDB_PY_HANDLE_EXCEPTION (except);
 819
 820 #ifdef HAVE_LONG_LONG           /* Defined by Python.  */
 821   return PyLong_FromLongLong (l);
 822 #else
 823   return PyLong_FromLong (l);
 824 #endif
 825 }
 826
 827 /* Implements conversion to float.  */
 828 static PyObject *
 829 valpy_float (PyObject *self)
 830 {
 831   struct value *value = ((value_object *) self)->value;
 832   struct type *type = value_type (value);
 833   double d = 0;
 834   volatile struct gdb_exception except;
 835
 836   CHECK_TYPEDEF (type);
 837   if (TYPE_CODE (type) != TYPE_CODE_FLT)
 838     {
 839       PyErr_SetString (PyExc_RuntimeError, "cannot convert value to float");
 840       return NULL;
 841     }
 842
 843   TRY_CATCH (except, RETURN_MASK_ALL)
 844     {
 845       d = value_as_double (value);
 846     }
 847   GDB_PY_HANDLE_EXCEPTION (except);
 848
 849   return PyFloat_FromDouble (d);
 850 }
 851
 852 /* Returns an object for a value which is released from the all_values chain,
 853    so its lifetime is not bound to the execution of a command.  */
 854 PyObject *
 855 value_to_value_object (struct value *val)
 856 {
 857   value_object *val_obj;
 858
 859   val_obj = PyObject_New (value_object, &value_object_type);
 860   if (val_obj != NULL)
 861     {
 862       val_obj->value = val;
 863       value_incref (val);
 864       val_obj->address = NULL;
 865       val_obj->type = NULL;
 866       note_value (val_obj);
 867     }
 868
 869   return (PyObject *) val_obj;
 870 }
 871
 872 /* Returns a borrowed reference to the struct value corresponding to
 873    the given value object.  */
 874 struct value *
 875 value_object_to_value (PyObject *self)
 876 {
 877   value_object *real;
 878   if (! PyObject_TypeCheck (self, &value_object_type))
 879     return NULL;
 880   real = (value_object *) self;
 881   return real->value;
 882 }
 883
 884 /* Try to convert a Python value to a gdb value.  If the value cannot
 885    be converted, set a Python exception and return NULL.  Returns a
 886    reference to a new value on the all_values chain.  */
 887
 888 struct value *
 889 convert_value_from_python (PyObject *obj)
 890 {
 891   struct value *value = NULL; /* -Wall */
 892   PyObject *target_str, *unicode_str;
 893   struct cleanup *old;
 894   volatile struct gdb_exception except;
 895   int cmp;
 896
 897   gdb_assert (obj != NULL);
 898
 899   TRY_CATCH (except, RETURN_MASK_ALL)
 900     {
 901       if (PyBool_Check (obj))
 902         {
 903           cmp = PyObject_IsTrue (obj);
 904           if (cmp >= 0)
 905             value = value_from_longest (builtin_type_pybool, cmp);
 906         }
 907       else if (PyInt_Check (obj))
 908         {
 909           long l = PyInt_AsLong (obj);
 910
 911           if (! PyErr_Occurred ())
 912             value = value_from_longest (builtin_type_pyint, l);
 913         }
 914       else if (PyLong_Check (obj))
 915         {
 916           LONGEST l = PyLong_AsLongLong (obj);
 917
 918           if (! PyErr_Occurred ())
 919             value = value_from_longest (builtin_type_pylong, l);
 920         }
 921       else if (PyFloat_Check (obj))
 922         {
 923           double d = PyFloat_AsDouble (obj);
 924
 925           if (! PyErr_Occurred ())
 926             value = value_from_double (builtin_type_pyfloat, d);
 927         }
 928       else if (gdbpy_is_string (obj))
 929         {
 930           char *s;
 931
 932           s = python_string_to_target_string (obj);
 933           if (s != NULL)
 934             {
 935               old = make_cleanup (xfree, s);
 936               value = value_cstring (s, strlen (s), builtin_type_pychar);
 937               do_cleanups (old);
 938             }
 939         }
 940       else if (PyObject_TypeCheck (obj, &value_object_type))
 941         value = value_copy (((value_object *) obj)->value);
 942       else
 943         PyErr_Format (PyExc_TypeError, _("Could not convert Python object: %s"),
 944                       PyString_AsString (PyObject_Str (obj)));
 945     }
 946   if (except.reason < 0)
 947     {
 948       PyErr_Format (except.reason == RETURN_QUIT
 949                     ? PyExc_KeyboardInterrupt : PyExc_RuntimeError,
 950                     "%s", except.message);
 951       return NULL;
 952     }
 953
 954   return value;
 955 }
 956
 957 /* Returns value object in the ARGth position in GDB's history.  */
 958 PyObject *
 959 gdbpy_history (PyObject *self, PyObject *args)
 960 {
 961   int i;
 962   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 963   volatile struct gdb_exception except;
 964
 965   if (!PyArg_ParseTuple (args, "i", &i))
 966     return NULL;
 967
 968   TRY_CATCH (except, RETURN_MASK_ALL)
 969     {
 970       res_val = access_value_history (i);
 971     }
 972   GDB_PY_HANDLE_EXCEPTION (except);
 973
 974   return value_to_value_object (res_val);
 975 }
 976
 977 void
 978 gdbpy_initialize_values (void)
 979 {
 980   if (PyType_Ready (&value_object_type) < 0)
 981     return;
 982
 983   Py_INCREF (&value_object_type);
 984   PyModule_AddObject (gdb_module, "Value", (PyObject *) &value_object_type);
 985
 986   values_in_python = NULL;
 987 }
 988
 989 \f
 990
 991 static PyGetSetDef value_object_getset[] = {
 992   { "address", valpy_get_address, NULL, "The address of the value.",
 993     NULL },
 994   { "is_optimized_out", valpy_get_is_optimized_out, NULL,
 995     "Boolean telling whether the value is optimized out (i.e., not available).",
 996     NULL },
 997   { "type", valpy_get_type, NULL, "Type of the value.", NULL },
 998   {NULL}  /* Sentinel */
 999 };
1000
1001 static PyMethodDef value_object_methods[] = {
1002   { "cast", valpy_cast, METH_VARARGS, "Cast the value to the supplied type." },
1003   { "dereference", valpy_dereference, METH_NOARGS, "Dereferences the value." },
1004   { "string", (PyCFunction) valpy_string, METH_VARARGS | METH_KEYWORDS,
1005     "string ([encoding] [, errors] [, length]) -> string\n\
1006 Return Unicode string representation of the value." },
1007   {NULL}  /* Sentinel */
1008 };
1009
1010 static PyNumberMethods value_object_as_number = {
1011   valpy_add,
1012   valpy_subtract,
1013   valpy_multiply,
1014   valpy_divide,
1015   valpy_remainder,
1016   NULL,                       /* nb_divmod */
1017   valpy_power,                /* nb_power */
1018   valpy_negative,             /* nb_negative */
1019   valpy_positive,             /* nb_positive */
1020   valpy_absolute,             /* nb_absolute */
1021   valpy_nonzero,              /* nb_nonzero */
1022   valpy_invert,               /* nb_invert */
1023   valpy_lsh,                  /* nb_lshift */
1024   valpy_rsh,                  /* nb_rshift */
1025   valpy_and,                  /* nb_and */
1026   valpy_xor,                  /* nb_xor */
1027   valpy_or,                   /* nb_or */
1028   NULL,                       /* nb_coerce */
1029   valpy_int,                  /* nb_int */
1030   valpy_long,                 /* nb_long */
1031   valpy_float,                /* nb_float */
1032   NULL,                       /* nb_oct */
1033   NULL                        /* nb_hex */
1034 };
1035
1036 static PyMappingMethods value_object_as_mapping = {
1037   valpy_length,
1038   valpy_getitem,
1039   valpy_setitem
1040 };
1041
1042 PyTypeObject value_object_type = {
1043   PyObject_HEAD_INIT (NULL)
1044   0,                              /*ob_size*/
1045   "gdb.Value",                    /*tp_name*/
1046   sizeof (value_object),          /*tp_basicsize*/
1047   0,                              /*tp_itemsize*/
1048   valpy_dealloc,                  /*tp_dealloc*/
1049   0,                              /*tp_print*/
1050   0,                              /*tp_getattr*/
1051   0,                              /*tp_setattr*/
1052   0,                              /*tp_compare*/
1053   0,                              /*tp_repr*/
1054   &value_object_as_number,        /*tp_as_number*/
1055   0,                              /*tp_as_sequence*/
1056   &value_object_as_mapping,       /*tp_as_mapping*/
1057   0,                              /*tp_hash */
1058   0,                              /*tp_call*/
1059   valpy_str,                      /*tp_str*/
1060   0,                              /*tp_getattro*/
1061   0,                              /*tp_setattro*/
1062   0,                              /*tp_as_buffer*/
1063   Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES,   /*tp_flags*/
1064   "GDB value object",             /* tp_doc */
1065   0,                              /* tp_traverse */
1066   0,                              /* tp_clear */
1067   valpy_richcompare,              /* tp_richcompare */
1068   0,                              /* tp_weaklistoffset */
1069   0,                              /* tp_iter */
1070   0,                              /* tp_iternext */
1071   value_object_methods,           /* tp_methods */
1072   0,                              /* tp_members */
1073   value_object_getset,            /* tp_getset */
1074   0,                              /* tp_base */
1075   0,                              /* tp_dict */
1076   0,                              /* tp_descr_get */
1077   0,                              /* tp_descr_set */
1078   0,                              /* tp_dictoffset */
1079   0,                              /* tp_init */
1080   0,                              /* tp_alloc */
1081   valpy_new                       /* tp_new */
1082 };
1083
1084 #else
1085
1086 void
1087 preserve_python_values (struct objfile *objfile, htab_t copied_types)
1088 {
1089   /* Nothing.  */
1090 }
1091
1092 #endif /* HAVE_PYTHON */