gdb/c-varobj.c

   1 /* varobj support for C and C++.
   2
   3    Copyright (C) 1999-2015 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include "defs.h"
  19 #include "value.h"
  20 #include "varobj.h"
  21 #include "gdbthread.h"
  22 #include "valprint.h"
  23
  24 static void cplus_class_num_children (struct type *type, int children[3]);
  25
  26 /* The names of varobjs representing anonymous structs or unions.  */
  27 #define ANONYMOUS_STRUCT_NAME _("<anonymous struct>")
  28 #define ANONYMOUS_UNION_NAME _("<anonymous union>")
  29
  30 /* Does CHILD represent a child with no name?  This happens when
  31    the child is an anonmous struct or union and it has no field name
  32    in its parent variable.
  33
  34    This has already been determined by *_describe_child. The easiest
  35    thing to do is to compare the child's name with ANONYMOUS_*_NAME.  */
  36
  37 int
  38 varobj_is_anonymous_child (const struct varobj *child)
  39 {
  40   return (strcmp (child->name, ANONYMOUS_STRUCT_NAME) == 0
  41           || strcmp (child->name, ANONYMOUS_UNION_NAME) == 0);
  42 }
  43
  44 /* Given the value and the type of a variable object,
  45    adjust the value and type to those necessary
  46    for getting children of the variable object.
  47    This includes dereferencing top-level references
  48    to all types and dereferencing pointers to
  49    structures.
  50
  51    If LOOKUP_ACTUAL_TYPE is set the enclosing type of the
  52    value will be fetched and if it differs from static type
  53    the value will be casted to it.
  54
  55    Both TYPE and *TYPE should be non-null.  VALUE
  56    can be null if we want to only translate type.
  57    *VALUE can be null as well -- if the parent
  58    value is not known.
  59
  60    If WAS_PTR is not NULL, set *WAS_PTR to 0 or 1
  61    depending on whether pointer was dereferenced
  62    in this function.  */
  63
  64 static void
  65 adjust_value_for_child_access (struct value **value,
  66                                   struct type **type,
  67                                   int *was_ptr,
  68                                   int lookup_actual_type)
  69 {
  70   gdb_assert (type && *type);
  71
  72   if (was_ptr)
  73     *was_ptr = 0;
  74
  75   *type = check_typedef (*type);
  76
  77   /* The type of value stored in varobj, that is passed
  78      to us, is already supposed to be
  79      reference-stripped.  */
  80
  81   gdb_assert (TYPE_CODE (*type) != TYPE_CODE_REF);
  82
  83   /* Pointers to structures are treated just like
  84      structures when accessing children.  Don't
  85      dererences pointers to other types.  */
  86   if (TYPE_CODE (*type) == TYPE_CODE_PTR)
  87     {
  88       struct type *target_type = get_target_type (*type);
  89       if (TYPE_CODE (target_type) == TYPE_CODE_STRUCT
  90           || TYPE_CODE (target_type) == TYPE_CODE_UNION)
  91         {
  92           if (value && *value)
  93             {
  94
  95               TRY
  96                 {
  97                   *value = value_ind (*value);
  98                 }
  99
 100               CATCH (except, RETURN_MASK_ERROR)
 101                 {
 102                   *value = NULL;
 103                 }
 104               END_CATCH
 105             }
 106           *type = target_type;
 107           if (was_ptr)
 108             *was_ptr = 1;
 109         }
 110     }
 111
 112   /* The 'get_target_type' function calls check_typedef on
 113      result, so we can immediately check type code.  No
 114      need to call check_typedef here.  */
 115
 116   /* Access a real type of the value (if necessary and possible).  */
 117   if (value && *value && lookup_actual_type)
 118     {
 119       struct type *enclosing_type;
 120       int real_type_found = 0;
 121
 122       enclosing_type = value_actual_type (*value, 1, &real_type_found);
 123       if (real_type_found)
 124         {
 125           *type = enclosing_type;
 126           *value = value_cast (enclosing_type, *value);
 127         }
 128     }
 129 }
 130
 131 /* Is VAR a path expression parent, i.e., can it be used to construct
 132    a valid path expression?  */
 133
 134 static int
 135 c_is_path_expr_parent (const struct varobj *var)
 136 {
 137   struct type *type;
 138
 139   /* "Fake" children are not path_expr parents.  */
 140   if (CPLUS_FAKE_CHILD (var))
 141     return 0;
 142
 143   type = varobj_get_gdb_type (var);
 144
 145   /* Anonymous unions and structs are also not path_expr parents.  */
 146   if ((TYPE_CODE (type) == TYPE_CODE_STRUCT
 147        || TYPE_CODE (type) == TYPE_CODE_UNION)
 148       && TYPE_NAME (type) == NULL
 149       && TYPE_TAG_NAME (type) == NULL)
 150     {
 151       const struct varobj *parent = var->parent;
 152
 153       while (parent != NULL && CPLUS_FAKE_CHILD (parent))
 154         parent = parent->parent;
 155
 156       if (parent != NULL)
 157         {
 158           struct type *parent_type;
 159           int was_ptr;
 160
 161           parent_type = varobj_get_value_type (parent);
 162           adjust_value_for_child_access (NULL, &parent_type, &was_ptr, 0);
 163
 164           if (TYPE_CODE (parent_type) == TYPE_CODE_STRUCT
 165               || TYPE_CODE (parent_type) == TYPE_CODE_UNION)
 166             {
 167               const char *field_name;
 168
 169               gdb_assert (var->index < TYPE_NFIELDS (parent_type));
 170               field_name = TYPE_FIELD_NAME (parent_type, var->index);
 171               return !(field_name == NULL || *field_name == '\0');
 172             }
 173         }
 174
 175       return 0;
 176     }
 177
 178   return 1;
 179 }
 180
 181 /* C */
 182
 183 static int
 184 c_number_of_children (const struct varobj *var)
 185 {
 186   struct type *type = varobj_get_value_type (var);
 187   int children = 0;
 188   struct type *target;
 189
 190   adjust_value_for_child_access (NULL, &type, NULL, 0);
 191   target = get_target_type (type);
 192
 193   switch (TYPE_CODE (type))
 194     {
 195     case TYPE_CODE_ARRAY:
 196       if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (target) > 0
 197           && !TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (type))
 198         children = TYPE_LENGTH (type) / TYPE_LENGTH (target);
 199       else
 200         /* If we don't know how many elements there are, don't display
 201            any.  */
 202         children = 0;
 203       break;
 204
 205     case TYPE_CODE_STRUCT:
 206     case TYPE_CODE_UNION:
 207       children = TYPE_NFIELDS (type);
 208       break;
 209
 210     case TYPE_CODE_PTR:
 211       /* The type here is a pointer to non-struct.  Typically, pointers
 212          have one child, except for function ptrs, which have no children,
 213          and except for void*, as we don't know what to show.
 214
 215          We can show char* so we allow it to be dereferenced.  If you decide
 216          to test for it, please mind that a little magic is necessary to
 217          properly identify it: char* has TYPE_CODE == TYPE_CODE_INT and
 218          TYPE_NAME == "char".  */
 219       if (TYPE_CODE (target) == TYPE_CODE_FUNC
 220           || TYPE_CODE (target) == TYPE_CODE_VOID)
 221         children = 0;
 222       else
 223         children = 1;
 224       break;
 225
 226     default:
 227       /* Other types have no children.  */
 228       break;
 229     }
 230
 231   return children;
 232 }
 233
 234 static char *
 235 c_name_of_variable (const struct varobj *parent)
 236 {
 237   return xstrdup (parent->name);
 238 }
 239
 240 /* Return the value of element TYPE_INDEX of a structure
 241    value VALUE.  VALUE's type should be a structure,
 242    or union, or a typedef to struct/union.
 243
 244    Returns NULL if getting the value fails.  Never throws.  */
 245
 246 static struct value *
 247 value_struct_element_index (struct value *value, int type_index)
 248 {
 249   struct value *result = NULL;
 250   struct type *type = value_type (value);
 251
 252   type = check_typedef (type);
 253
 254   gdb_assert (TYPE_CODE (type) == TYPE_CODE_STRUCT
 255               || TYPE_CODE (type) == TYPE_CODE_UNION);
 256
 257   TRY
 258     {
 259       if (field_is_static (&TYPE_FIELD (type, type_index)))
 260         result = value_static_field (type, type_index);
 261       else
 262         result = value_primitive_field (value, 0, type_index, type);
 263     }
 264   CATCH (e, RETURN_MASK_ERROR)
 265     {
 266       return NULL;
 267     }
 268   END_CATCH
 269
 270   return result;
 271 }
 272
 273 /* Obtain the information about child INDEX of the variable
 274    object PARENT.
 275    If CNAME is not null, sets *CNAME to the name of the child relative
 276    to the parent.
 277    If CVALUE is not null, sets *CVALUE to the value of the child.
 278    If CTYPE is not null, sets *CTYPE to the type of the child.
 279
 280    If any of CNAME, CVALUE, or CTYPE is not null, but the corresponding
 281    information cannot be determined, set *CNAME, *CVALUE, or *CTYPE
 282    to NULL.  */
 283
 284 static void
 285 c_describe_child (const struct varobj *parent, int index,
 286                   char **cname, struct value **cvalue, struct type **ctype,
 287                   char **cfull_expression)
 288 {
 289   struct value *value = parent->value;
 290   struct type *type = varobj_get_value_type (parent);
 291   char *parent_expression = NULL;
 292   int was_ptr;
 293
 294   if (cname)
 295     *cname = NULL;
 296   if (cvalue)
 297     *cvalue = NULL;
 298   if (ctype)
 299     *ctype = NULL;
 300   if (cfull_expression)
 301     {
 302       *cfull_expression = NULL;
 303       parent_expression
 304         = varobj_get_path_expr (varobj_get_path_expr_parent (parent));
 305     }
 306   adjust_value_for_child_access (&value, &type, &was_ptr, 0);
 307
 308   switch (TYPE_CODE (type))
 309     {
 310     case TYPE_CODE_ARRAY:
 311       if (cname)
 312         *cname
 313           = xstrdup (int_string (index
 314                                  + TYPE_LOW_BOUND (TYPE_INDEX_TYPE (type)),
 315                                  10, 1, 0, 0));
 316
 317       if (cvalue && value)
 318         {
 319           int real_index = index + TYPE_LOW_BOUND (TYPE_INDEX_TYPE (type));
 320
 321           TRY
 322             {
 323               *cvalue = value_subscript (value, real_index);
 324             }
 325           CATCH (except, RETURN_MASK_ERROR)
 326             {
 327             }
 328           END_CATCH
 329         }
 330
 331       if (ctype)
 332         *ctype = get_target_type (type);
 333
 334       if (cfull_expression)
 335         *cfull_expression =
 336           xstrprintf ("(%s)[%s]", parent_expression,
 337                       int_string (index
 338                                   + TYPE_LOW_BOUND (TYPE_INDEX_TYPE (type)),
 339                                   10, 1, 0, 0));
 340
 341
 342       break;
 343
 344     case TYPE_CODE_STRUCT:
 345     case TYPE_CODE_UNION:
 346       {
 347         const char *field_name;
 348
 349         /* If the type is anonymous and the field has no name,
 350            set an appropriate name.  */
 351         field_name = TYPE_FIELD_NAME (type, index);
 352         if (field_name == NULL || *field_name == '\0')
 353           {
 354             if (cname)
 355               {
 356                 if (TYPE_CODE (TYPE_FIELD_TYPE (type, index))
 357                     == TYPE_CODE_STRUCT)
 358                   *cname = xstrdup (ANONYMOUS_STRUCT_NAME);
 359                 else
 360                   *cname = xstrdup (ANONYMOUS_UNION_NAME);
 361               }
 362
 363             if (cfull_expression)
 364               *cfull_expression = xstrdup ("");
 365           }
 366         else
 367           {
 368             if (cname)
 369               *cname = xstrdup (field_name);
 370
 371             if (cfull_expression)
 372               {
 373                 char *join = was_ptr ? "->" : ".";
 374
 375                 *cfull_expression = xstrprintf ("(%s)%s%s", parent_expression,
 376                                                 join, field_name);
 377               }
 378           }
 379
 380         if (cvalue && value)
 381           {
 382             /* For C, varobj index is the same as type index.  */
 383             *cvalue = value_struct_element_index (value, index);
 384           }
 385
 386         if (ctype)
 387           *ctype = TYPE_FIELD_TYPE (type, index);
 388       }
 389       break;
 390
 391     case TYPE_CODE_PTR:
 392       if (cname)
 393         *cname = xstrprintf ("*%s", parent->name);
 394
 395       if (cvalue && value)
 396         {
 397           TRY
 398             {
 399               *cvalue = value_ind (value);
 400             }
 401
 402           CATCH (except, RETURN_MASK_ERROR)
 403             {
 404               *cvalue = NULL;
 405             }
 406           END_CATCH
 407         }
 408
 409       /* Don't use get_target_type because it calls
 410          check_typedef and here, we want to show the true
 411          declared type of the variable.  */
 412       if (ctype)
 413         *ctype = TYPE_TARGET_TYPE (type);
 414
 415       if (cfull_expression)
 416         *cfull_expression = xstrprintf ("*(%s)", parent_expression);
 417
 418       break;
 419
 420     default:
 421       /* This should not happen.  */
 422       if (cname)
 423         *cname = xstrdup ("???");
 424       if (cfull_expression)
 425         *cfull_expression = xstrdup ("???");
 426       /* Don't set value and type, we don't know then.  */
 427     }
 428 }
 429
 430 static char *
 431 c_name_of_child (const struct varobj *parent, int index)
 432 {
 433   char *name;
 434
 435   c_describe_child (parent, index, &name, NULL, NULL, NULL);
 436   return name;
 437 }
 438
 439 static char *
 440 c_path_expr_of_child (const struct varobj *child)
 441 {
 442   char *path_expr;
 443
 444   c_describe_child (child->parent, child->index, NULL, NULL, NULL,
 445                     &path_expr);
 446   return path_expr;
 447 }
 448
 449 static struct value *
 450 c_value_of_child (const struct varobj *parent, int index)
 451 {
 452   struct value *value = NULL;
 453
 454   c_describe_child (parent, index, NULL, &value, NULL, NULL);
 455   return value;
 456 }
 457
 458 static struct type *
 459 c_type_of_child (const struct varobj *parent, int index)
 460 {
 461   struct type *type = NULL;
 462
 463   c_describe_child (parent, index, NULL, NULL, &type, NULL);
 464   return type;
 465 }
 466
 467 /* This returns the type of the variable.  It also skips past typedefs
 468    to return the real type of the variable.  */
 469
 470 static struct type *
 471 get_type (const struct varobj *var)
 472 {
 473   struct type *type;
 474
 475   type = var->type;
 476   if (type != NULL)
 477     type = check_typedef (type);
 478
 479   return type;
 480 }
 481
 482 static char *
 483 c_value_of_variable (const struct varobj *var,
 484                      enum varobj_display_formats format)
 485 {
 486   /* BOGUS: if val_print sees a struct/class, or a reference to one,
 487      it will print out its children instead of "{...}".  So we need to
 488      catch that case explicitly.  */
 489   struct type *type = get_type (var);
 490
 491   /* Strip top-level references.  */
 492   while (TYPE_CODE (type) == TYPE_CODE_REF)
 493     type = check_typedef (TYPE_TARGET_TYPE (type));
 494
 495   switch (TYPE_CODE (type))
 496     {
 497     case TYPE_CODE_STRUCT:
 498     case TYPE_CODE_UNION:
 499       return xstrdup ("{...}");
 500       /* break; */
 501
 502     case TYPE_CODE_ARRAY:
 503       {
 504         char *number;
 505
 506         number = xstrprintf ("[%d]", var->num_children);
 507         return (number);
 508       }
 509       /* break; */
 510
 511     default:
 512       {
 513         if (var->value == NULL)
 514           {
 515             /* This can happen if we attempt to get the value of a struct
 516                member when the parent is an invalid pointer.  This is an
 517                error condition, so we should tell the caller.  */
 518             return NULL;
 519           }
 520         else
 521           {
 522             if (var->not_fetched && value_lazy (var->value))
 523               /* Frozen variable and no value yet.  We don't
 524                  implicitly fetch the value.  MI response will
 525                  use empty string for the value, which is OK.  */
 526               return NULL;
 527
 528             gdb_assert (varobj_value_is_changeable_p (var));
 529             gdb_assert (!value_lazy (var->value));
 530
 531             /* If the specified format is the current one,
 532                we can reuse print_value.  */
 533             if (format == var->format)
 534               return xstrdup (var->print_value);
 535             else
 536               return varobj_value_get_print_value (var->value, format, var);
 537           }
 538       }
 539     }
 540 }
 541 \f
 542
 543 /* varobj operations for c.  */
 544
 545 const struct lang_varobj_ops c_varobj_ops =
 546 {
 547    c_number_of_children,
 548    c_name_of_variable,
 549    c_name_of_child,
 550    c_path_expr_of_child,
 551    c_value_of_child,
 552    c_type_of_child,
 553    c_value_of_variable,
 554    varobj_default_value_is_changeable_p,
 555    NULL, /* value_has_mutated */
 556    c_is_path_expr_parent  /* is_path_expr_parent */
 557 };
 558
 559 /* A little convenience enum for dealing with C++/Java.  */
 560 enum vsections
 561 {
 562   v_public = 0, v_private, v_protected
 563 };
 564
 565 /* C++ */
 566
 567 static int
 568 cplus_number_of_children (const struct varobj *var)
 569 {
 570   struct value *value = NULL;
 571   struct type *type;
 572   int children, dont_know;
 573   int lookup_actual_type = 0;
 574   struct value_print_options opts;
 575
 576   dont_know = 1;
 577   children = 0;
 578
 579   get_user_print_options (&opts);
 580
 581   if (!CPLUS_FAKE_CHILD (var))
 582     {
 583       type = varobj_get_value_type (var);
 584
 585       /* It is necessary to access a real type (via RTTI).  */
 586       if (opts.objectprint)
 587         {
 588           value = var->value;
 589           lookup_actual_type = (TYPE_CODE (var->type) == TYPE_CODE_REF
 590                                 || TYPE_CODE (var->type) == TYPE_CODE_PTR);
 591         }
 592       adjust_value_for_child_access (&value, &type, NULL, lookup_actual_type);
 593
 594       if (((TYPE_CODE (type)) == TYPE_CODE_STRUCT)
 595           || ((TYPE_CODE (type)) == TYPE_CODE_UNION))
 596         {
 597           int kids[3];
 598
 599           cplus_class_num_children (type, kids);
 600           if (kids[v_public] != 0)
 601             children++;
 602           if (kids[v_private] != 0)
 603             children++;
 604           if (kids[v_protected] != 0)
 605             children++;
 606
 607           /* Add any baseclasses.  */
 608           children += TYPE_N_BASECLASSES (type);
 609           dont_know = 0;
 610
 611           /* FIXME: save children in var.  */
 612         }
 613     }
 614   else
 615     {
 616       int kids[3];
 617
 618       type = varobj_get_value_type (var->parent);
 619
 620       /* It is necessary to access a real type (via RTTI).  */
 621       if (opts.objectprint)
 622         {
 623           const struct varobj *parent = var->parent;
 624
 625           value = parent->value;
 626           lookup_actual_type = (TYPE_CODE (parent->type) == TYPE_CODE_REF
 627                                 || TYPE_CODE (parent->type) == TYPE_CODE_PTR);
 628         }
 629       adjust_value_for_child_access (&value, &type, NULL, lookup_actual_type);
 630
 631       cplus_class_num_children (type, kids);
 632       if (strcmp (var->name, "public") == 0)
 633         children = kids[v_public];
 634       else if (strcmp (var->name, "private") == 0)
 635         children = kids[v_private];
 636       else
 637         children = kids[v_protected];
 638       dont_know = 0;
 639     }
 640
 641   if (dont_know)
 642     children = c_number_of_children (var);
 643
 644   return children;
 645 }
 646
 647 /* Compute # of public, private, and protected variables in this class.
 648    That means we need to descend into all baseclasses and find out
 649    how many are there, too.  */
 650
 651 static void
 652 cplus_class_num_children (struct type *type, int children[3])
 653 {
 654   int i, vptr_fieldno;
 655   struct type *basetype = NULL;
 656
 657   children[v_public] = 0;
 658   children[v_private] = 0;
 659   children[v_protected] = 0;
 660
 661   vptr_fieldno = get_vptr_fieldno (type, &basetype);
 662   for (i = TYPE_N_BASECLASSES (type); i < TYPE_NFIELDS (type); i++)
 663     {
 664       /* If we have a virtual table pointer, omit it.  Even if virtual
 665          table pointers are not specifically marked in the debug info,
 666          they should be artificial.  */
 667       if ((type == basetype && i == vptr_fieldno)
 668           || TYPE_FIELD_ARTIFICIAL (type, i))
 669         continue;
 670
 671       if (TYPE_FIELD_PROTECTED (type, i))
 672         children[v_protected]++;
 673       else if (TYPE_FIELD_PRIVATE (type, i))
 674         children[v_private]++;
 675       else
 676         children[v_public]++;
 677     }
 678 }
 679
 680 static char *
 681 cplus_name_of_variable (const struct varobj *parent)
 682 {
 683   return c_name_of_variable (parent);
 684 }
 685
 686 enum accessibility { private_field, protected_field, public_field };
 687
 688 /* Check if field INDEX of TYPE has the specified accessibility.
 689    Return 0 if so and 1 otherwise.  */
 690
 691 static int
 692 match_accessibility (struct type *type, int index, enum accessibility acc)
 693 {
 694   if (acc == private_field && TYPE_FIELD_PRIVATE (type, index))
 695     return 1;
 696   else if (acc == protected_field && TYPE_FIELD_PROTECTED (type, index))
 697     return 1;
 698   else if (acc == public_field && !TYPE_FIELD_PRIVATE (type, index)
 699            && !TYPE_FIELD_PROTECTED (type, index))
 700     return 1;
 701   else
 702     return 0;
 703 }
 704
 705 static void
 706 cplus_describe_child (const struct varobj *parent, int index,
 707                       char **cname, struct value **cvalue, struct type **ctype,
 708                       char **cfull_expression)
 709 {
 710   struct value *value;
 711   struct type *type;
 712   int was_ptr;
 713   int lookup_actual_type = 0;
 714   char *parent_expression = NULL;
 715   const struct varobj *var;
 716   struct value_print_options opts;
 717
 718   if (cname)
 719     *cname = NULL;
 720   if (cvalue)
 721     *cvalue = NULL;
 722   if (ctype)
 723     *ctype = NULL;
 724   if (cfull_expression)
 725     *cfull_expression = NULL;
 726
 727   get_user_print_options (&opts);
 728
 729   var = (CPLUS_FAKE_CHILD (parent)) ? parent->parent : parent;
 730   if (opts.objectprint)
 731     lookup_actual_type = (TYPE_CODE (var->type) == TYPE_CODE_REF
 732                           || TYPE_CODE (var->type) == TYPE_CODE_PTR);
 733   value = var->value;
 734   type = varobj_get_value_type (var);
 735   if (cfull_expression)
 736     parent_expression
 737       = varobj_get_path_expr (varobj_get_path_expr_parent (var));
 738
 739   adjust_value_for_child_access (&value, &type, &was_ptr, lookup_actual_type);
 740
 741   if (TYPE_CODE (type) == TYPE_CODE_STRUCT
 742       || TYPE_CODE (type) == TYPE_CODE_UNION)
 743     {
 744       char *join = was_ptr ? "->" : ".";
 745
 746       if (CPLUS_FAKE_CHILD (parent))
 747         {
 748           /* The fields of the class type are ordered as they
 749              appear in the class.  We are given an index for a
 750              particular access control type ("public","protected",
 751              or "private").  We must skip over fields that don't
 752              have the access control we are looking for to properly
 753              find the indexed field.  */
 754           int type_index = TYPE_N_BASECLASSES (type);
 755           enum accessibility acc = public_field;
 756           int vptr_fieldno;
 757           struct type *basetype = NULL;
 758           const char *field_name;
 759
 760           vptr_fieldno = get_vptr_fieldno (type, &basetype);
 761           if (strcmp (parent->name, "private") == 0)
 762             acc = private_field;
 763           else if (strcmp (parent->name, "protected") == 0)
 764             acc = protected_field;
 765
 766           while (index >= 0)
 767             {
 768               if ((type == basetype && type_index == vptr_fieldno)
 769                   || TYPE_FIELD_ARTIFICIAL (type, type_index))
 770                 ; /* ignore vptr */
 771               else if (match_accessibility (type, type_index, acc))
 772                     --index;
 773                   ++type_index;
 774             }
 775           --type_index;
 776
 777           /* If the type is anonymous and the field has no name,
 778              set an appopriate name.  */
 779           field_name = TYPE_FIELD_NAME (type, type_index);
 780           if (field_name == NULL || *field_name == '\0')
 781             {
 782               if (cname)
 783                 {
 784                   if (TYPE_CODE (TYPE_FIELD_TYPE (type, type_index))
 785                       == TYPE_CODE_STRUCT)
 786                     *cname = xstrdup (ANONYMOUS_STRUCT_NAME);
 787                   else if (TYPE_CODE (TYPE_FIELD_TYPE (type, type_index))
 788                            == TYPE_CODE_UNION)
 789                     *cname = xstrdup (ANONYMOUS_UNION_NAME);
 790                 }
 791
 792               if (cfull_expression)
 793                 *cfull_expression = xstrdup ("");
 794             }
 795           else
 796             {
 797               if (cname)
 798                 *cname = xstrdup (TYPE_FIELD_NAME (type, type_index));
 799
 800               if (cfull_expression)
 801                 *cfull_expression
 802                   = xstrprintf ("((%s)%s%s)", parent_expression, join,
 803                                 field_name);
 804             }
 805
 806           if (cvalue && value)
 807             *cvalue = value_struct_element_index (value, type_index);
 808
 809           if (ctype)
 810             *ctype = TYPE_FIELD_TYPE (type, type_index);
 811         }
 812       else if (index < TYPE_N_BASECLASSES (type))
 813         {
 814           /* This is a baseclass.  */
 815           if (cname)
 816             *cname = xstrdup (TYPE_FIELD_NAME (type, index));
 817
 818           if (cvalue && value)
 819             *cvalue = value_cast (TYPE_FIELD_TYPE (type, index), value);
 820
 821           if (ctype)
 822             {
 823               *ctype = TYPE_FIELD_TYPE (type, index);
 824             }
 825
 826           if (cfull_expression)
 827             {
 828               char *ptr = was_ptr ? "*" : "";
 829
 830               /* Cast the parent to the base' type.  Note that in gdb,
 831                  expression like
 832                          (Base1)d
 833                  will create an lvalue, for all appearences, so we don't
 834                  need to use more fancy:
 835                          *(Base1*)(&d)
 836                  construct.
 837
 838                  When we are in the scope of the base class or of one
 839                  of its children, the type field name will be interpreted
 840                  as a constructor, if it exists.  Therefore, we must
 841                  indicate that the name is a class name by using the
 842                  'class' keyword.  See PR mi/11912  */
 843               *cfull_expression = xstrprintf ("(%s(class %s%s) %s)",
 844                                               ptr,
 845                                               TYPE_FIELD_NAME (type, index),
 846                                               ptr,
 847                                               parent_expression);
 848             }
 849         }
 850       else
 851         {
 852           char *access = NULL;
 853           int children[3];
 854
 855           cplus_class_num_children (type, children);
 856
 857           /* Everything beyond the baseclasses can
 858              only be "public", "private", or "protected"
 859
 860              The special "fake" children are always output by varobj in
 861              this order.  So if INDEX == 2, it MUST be "protected".  */
 862           index -= TYPE_N_BASECLASSES (type);
 863           switch (index)
 864             {
 865             case 0:
 866               if (children[v_public] > 0)
 867                 access = "public";
 868               else if (children[v_private] > 0)
 869                 access = "private";
 870               else
 871                 access = "protected";
 872               break;
 873             case 1:
 874               if (children[v_public] > 0)
 875                 {
 876                   if (children[v_private] > 0)
 877                     access = "private";
 878                   else
 879                     access = "protected";
 880                 }
 881               else if (children[v_private] > 0)
 882                 access = "protected";
 883               break;
 884             case 2:
 885               /* Must be protected.  */
 886               access = "protected";
 887               break;
 888             default:
 889               /* error!  */
 890               break;
 891             }
 892
 893           gdb_assert (access);
 894           if (cname)
 895             *cname = xstrdup (access);
 896
 897           /* Value and type and full expression are null here.  */
 898         }
 899     }
 900   else
 901     {
 902       c_describe_child (parent, index, cname, cvalue, ctype, cfull_expression);
 903     }
 904 }
 905
 906 static char *
 907 cplus_name_of_child (const struct varobj *parent, int index)
 908 {
 909   char *name = NULL;
 910
 911   cplus_describe_child (parent, index, &name, NULL, NULL, NULL);
 912   return name;
 913 }
 914
 915 static char *
 916 cplus_path_expr_of_child (const struct varobj *child)
 917 {
 918   char *path_expr;
 919
 920   cplus_describe_child (child->parent, child->index, NULL, NULL, NULL,
 921                         &path_expr);
 922   return path_expr;
 923 }
 924
 925 static struct value *
 926 cplus_value_of_child (const struct varobj *parent, int index)
 927 {
 928   struct value *value = NULL;
 929
 930   cplus_describe_child (parent, index, NULL, &value, NULL, NULL);
 931   return value;
 932 }
 933
 934 static struct type *
 935 cplus_type_of_child (const struct varobj *parent, int index)
 936 {
 937   struct type *type = NULL;
 938
 939   cplus_describe_child (parent, index, NULL, NULL, &type, NULL);
 940   return type;
 941 }
 942
 943 static char *
 944 cplus_value_of_variable (const struct varobj *var,
 945                          enum varobj_display_formats format)
 946 {
 947
 948   /* If we have one of our special types, don't print out
 949      any value.  */
 950   if (CPLUS_FAKE_CHILD (var))
 951     return xstrdup ("");
 952
 953   return c_value_of_variable (var, format);
 954 }
 955 \f
 956
 957 /* varobj operations for c++.  */
 958
 959 const struct lang_varobj_ops cplus_varobj_ops =
 960 {
 961    cplus_number_of_children,
 962    cplus_name_of_variable,
 963    cplus_name_of_child,
 964    cplus_path_expr_of_child,
 965    cplus_value_of_child,
 966    cplus_type_of_child,
 967    cplus_value_of_variable,
 968    varobj_default_value_is_changeable_p,
 969    NULL, /* value_has_mutated */
 970    c_is_path_expr_parent  /* is_path_expr_parent */
 971 };
 972
 973 \f