gdb/cp-valprint.c

   1 /* Support for printing C++ values for GDB, the GNU debugger.
   2    Copyright 1986, 1988, 1989, 1991 Free Software Foundation, Inc.
   3
   4 This file is part of GDB.
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #include "defs.h"
  21 #include "obstack.h"
  22 #include "symtab.h"
  23 #include "gdbtypes.h"
  24 #include "expression.h"
  25 #include "value.h"
  26 #include "command.h"
  27 #include "gdbcmd.h"
  28 #include "demangle.h"
  29 #include "annotate.h"
  30
  31 int vtblprint;                  /* Controls printing of vtbl's */
  32 int objectprint;                /* Controls looking up an object's derived type
  33                                    using what we find in its vtables.  */
  34 static int static_field_print;  /* Controls printing of static fields. */
  35 struct obstack dont_print_obstack;
  36
  37 static void
  38 cplus_print_value PARAMS ((struct type *, char *, GDB_FILE *, int, int,
  39                            enum val_prettyprint, struct type **));
  40
  41 /* BEGIN-FIXME:  Hooks into typeprint.c, find a better home for prototypes. */
  42
  43 extern void
  44 c_type_print_base PARAMS ((struct type *, GDB_FILE *, int, int));
  45
  46 extern void
  47 c_type_print_varspec_prefix PARAMS ((struct type *, GDB_FILE *, int, int));
  48
  49 extern void
  50 cp_type_print_method_args PARAMS ((struct type **, char *, char *, int,
  51                                    GDB_FILE *));
  52
  53 extern struct obstack dont_print_obstack;
  54
  55 /* END-FIXME */
  56
  57 void
  58 cp_print_class_method (valaddr, type, stream)
  59      char *valaddr;
  60      struct type *type;
  61      GDB_FILE *stream;
  62 {
  63   struct type *domain;
  64   struct fn_field *f = NULL;
  65   int j = 0;
  66   int len2;
  67   int offset;
  68   char *kind = "";
  69   CORE_ADDR addr;
  70   struct symbol *sym;
  71   unsigned len;
  72   unsigned int i;
  73
  74   check_stub_type (TYPE_TARGET_TYPE (type));
  75   domain = TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (type));
  76   if (domain == (struct type *)NULL)
  77     {
  78       fprintf_filtered (stream, "<unknown>");
  79       return;
  80     }
  81   addr = unpack_pointer (lookup_pointer_type (builtin_type_void), valaddr);
  82   if (METHOD_PTR_IS_VIRTUAL (addr))
  83     {
  84       offset = METHOD_PTR_TO_VOFFSET (addr);
  85       len = TYPE_NFN_FIELDS (domain);
  86       for (i = 0; i < len; i++)
  87         {
  88           f = TYPE_FN_FIELDLIST1 (domain, i);
  89           len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i);
  90
  91           for (j = 0; j < len2; j++)
  92             {
  93               QUIT;
  94               if (TYPE_FN_FIELD_VOFFSET (f, j) == offset)
  95                 {
  96                   kind = "virtual ";
  97                   goto common;
  98                 }
  99             }
 100         }
 101     }
 102   else
 103     {
 104       sym = find_pc_function (addr);
 105       if (sym == 0)
 106         {
 107           error ("invalid pointer to member function");
 108         }
 109       len = TYPE_NFN_FIELDS (domain);
 110       for (i = 0; i < len; i++)
 111         {
 112           f = TYPE_FN_FIELDLIST1 (domain, i);
 113           len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i);
 114
 115           for (j = 0; j < len2; j++)
 116             {
 117               QUIT;
 118               if (TYPE_FN_FIELD_STUB (f, j))
 119                 check_stub_method (domain, i, j);
 120               if (STREQ (SYMBOL_NAME (sym), TYPE_FN_FIELD_PHYSNAME (f, j)))
 121                 {
 122                   goto common;
 123                 }
 124             }
 125         }
 126     }
 127   common:
 128   if (i < len)
 129     {
 130       fprintf_filtered (stream, "&");
 131       c_type_print_varspec_prefix (TYPE_FN_FIELD_TYPE (f, j), stream, 0, 0);
 132       fprintf_unfiltered (stream, kind);
 133       if (TYPE_FN_FIELD_PHYSNAME (f, j)[0] == '_'
 134           && TYPE_FN_FIELD_PHYSNAME (f, j)[1] == CPLUS_MARKER)
 135         {
 136           cp_type_print_method_args (TYPE_FN_FIELD_ARGS (f, j) + 1, "~",
 137                                      TYPE_FN_FIELDLIST_NAME (domain, i),
 138                                      0, stream);
 139         }
 140       else
 141         {
 142           cp_type_print_method_args (TYPE_FN_FIELD_ARGS (f, j), "",
 143                                      TYPE_FN_FIELDLIST_NAME (domain, i),
 144                                      0, stream);
 145         }
 146     }
 147   else
 148     {
 149       fprintf_filtered (stream, "(");
 150       type_print (type, "", stream, -1);
 151       fprintf_filtered (stream, ") %d", (int) addr >> 3);
 152     }
 153 }
 154
 155 /* This was what it was for gcc 2.4.5 and earlier.  */
 156 static const char vtbl_ptr_name_old[] =
 157   { CPLUS_MARKER,'v','t','b','l','_','p','t','r','_','t','y','p','e', 0 };
 158 /* It was changed to this after 2.4.5.  */
 159 const char vtbl_ptr_name[] =
 160   { '_','_','v','t','b','l','_','p','t','r','_','t','y','p','e', 0 };
 161
 162 /* Return truth value for assertion that TYPE is of the type
 163    "pointer to virtual function".  */
 164
 165 int
 166 cp_is_vtbl_ptr_type(type)
 167      struct type *type;
 168 {
 169   char *typename = type_name_no_tag (type);
 170
 171   return (typename != NULL
 172           && (STREQ (typename, vtbl_ptr_name)
 173               || STREQ (typename, vtbl_ptr_name_old)));
 174 }
 175
 176 /* Return truth value for the assertion that TYPE is of the type
 177    "pointer to virtual function table".  */
 178
 179 int
 180 cp_is_vtbl_member(type)
 181      struct type *type;
 182 {
 183   if (TYPE_CODE (type) == TYPE_CODE_PTR)
 184     {
 185       type = TYPE_TARGET_TYPE (type);
 186       if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
 187         {
 188           type = TYPE_TARGET_TYPE (type);
 189           if (TYPE_CODE (type) == TYPE_CODE_STRUCT /* if not using thunks */
 190               || TYPE_CODE (type) == TYPE_CODE_PTR) /* if using thunks */
 191             {
 192               /* Virtual functions tables are full of pointers
 193                  to virtual functions. */
 194               return cp_is_vtbl_ptr_type (type);
 195             }
 196         }
 197     }
 198   return 0;
 199 }
 200
 201 /* Mutually recursive subroutines of cplus_print_value and c_val_print to
 202    print out a structure's fields: cp_print_value_fields and cplus_print_value.
 203
 204    TYPE, VALADDR, STREAM, RECURSE, and PRETTY have the
 205    same meanings as in cplus_print_value and c_val_print.
 206
 207    DONT_PRINT is an array of baseclass types that we
 208    should not print, or zero if called from top level.  */
 209
 210 void
 211 cp_print_value_fields (type, valaddr, stream, format, recurse, pretty,
 212                        dont_print)
 213      struct type *type;
 214      char *valaddr;
 215      GDB_FILE *stream;
 216      int format;
 217      int recurse;
 218      enum val_prettyprint pretty;
 219      struct type **dont_print;
 220 {
 221   int i, len, n_baseclasses;
 222
 223   check_stub_type (type);
 224
 225   fprintf_filtered (stream, "{");
 226   len = TYPE_NFIELDS (type);
 227   n_baseclasses = TYPE_N_BASECLASSES (type);
 228
 229   /* Print out baseclasses such that we don't print
 230      duplicates of virtual baseclasses.  */
 231   if (n_baseclasses > 0)
 232     cplus_print_value (type, valaddr, stream, format, recurse+1, pretty,
 233                        dont_print);
 234
 235   if (!len && n_baseclasses == 1)
 236     fprintf_filtered (stream, "<No data fields>");
 237   else
 238     {
 239       extern int inspect_it;
 240       int fields_seen = 0;
 241
 242       for (i = n_baseclasses; i < len; i++)
 243         {
 244           /* If requested, skip printing of static fields.  */
 245           if (!static_field_print && TYPE_FIELD_STATIC (type, i))
 246             continue;
 247           if (fields_seen)
 248             fprintf_filtered (stream, ", ");
 249           else if (n_baseclasses > 0)
 250             {
 251               if (pretty)
 252                 {
 253                   fprintf_filtered (stream, "\n");
 254                   print_spaces_filtered (2 + 2 * recurse, stream);
 255                   fputs_filtered ("members of ", stream);
 256                   fputs_filtered (type_name_no_tag (type), stream);
 257                   fputs_filtered (": ", stream);
 258                 }
 259             }
 260           fields_seen = 1;
 261
 262           if (pretty)
 263             {
 264               fprintf_filtered (stream, "\n");
 265               print_spaces_filtered (2 + 2 * recurse, stream);
 266             }
 267           else
 268             {
 269               wrap_here (n_spaces (2 + 2 * recurse));
 270             }
 271           if (inspect_it)
 272             {
 273               if (TYPE_CODE (TYPE_FIELD_TYPE (type, i)) == TYPE_CODE_PTR)
 274                 fputs_filtered ("\"( ptr \"", stream);
 275               else
 276                 fputs_filtered ("\"( nodef \"", stream);
 277               if (TYPE_FIELD_STATIC (type, i))
 278                 fputs_filtered ("static ", stream);
 279               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 280                                        language_cplus,
 281                                        DMGL_PARAMS | DMGL_ANSI);
 282               fputs_filtered ("\" \"", stream);
 283               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 284                                        language_cplus,
 285                                        DMGL_PARAMS | DMGL_ANSI);
 286               fputs_filtered ("\") \"", stream);
 287             }
 288           else
 289             {
 290               annotate_field_begin (TYPE_FIELD_TYPE (type, i));
 291
 292               if (TYPE_FIELD_STATIC (type, i))
 293                 fputs_filtered ("static ", stream);
 294               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 295                                        language_cplus,
 296                                        DMGL_PARAMS | DMGL_ANSI);
 297               annotate_field_name_end ();
 298               fputs_filtered (" = ", stream);
 299               annotate_field_value ();
 300             }
 301
 302           if (!TYPE_FIELD_STATIC (type, i) && TYPE_FIELD_PACKED (type, i))
 303             {
 304               value_ptr v;
 305
 306               /* Bitfields require special handling, especially due to byte
 307                  order problems.  */
 308               if (TYPE_FIELD_IGNORE (type, i))
 309                 {
 310                    fputs_filtered ("<optimized out or zero length>", stream);
 311                 }
 312               else
 313                 {
 314                    v = value_from_longest (TYPE_FIELD_TYPE (type, i),
 315                                    unpack_field_as_long (type, valaddr, i));
 316
 317                    val_print (TYPE_FIELD_TYPE(type, i), VALUE_CONTENTS (v), 0,
 318                               stream, format, 0, recurse + 1, pretty);
 319                 }
 320             }
 321           else
 322             {
 323               if (TYPE_FIELD_IGNORE (type, i))
 324                 {
 325                    fputs_filtered ("<optimized out or zero length>", stream);
 326                 }
 327               else if (TYPE_FIELD_STATIC (type, i))
 328                 {
 329                   value_ptr v;
 330                   char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, i);
 331                   struct symbol *sym =
 332                       lookup_symbol (phys_name, 0, VAR_NAMESPACE, 0, NULL);
 333                   if (sym == NULL)
 334                     fputs_filtered ("<optimized out>", stream);
 335                   else
 336                     {
 337                       v = value_at (TYPE_FIELD_TYPE (type, i),
 338                                     (CORE_ADDR)SYMBOL_BLOCK_VALUE (sym));
 339                       val_print (TYPE_FIELD_TYPE (type, i),
 340                                  VALUE_CONTENTS_RAW (v),
 341                                  VALUE_ADDRESS (v),
 342                                  stream, format, 0, recurse + 1, pretty);
 343                     }
 344                 }
 345               else
 346                 {
 347                    val_print (TYPE_FIELD_TYPE (type, i),
 348                               valaddr + TYPE_FIELD_BITPOS (type, i) / 8,
 349                               0, stream, format, 0, recurse + 1, pretty);
 350                 }
 351             }
 352           annotate_field_end ();
 353         }
 354
 355       if (pretty)
 356         {
 357           fprintf_filtered (stream, "\n");
 358           print_spaces_filtered (2 * recurse, stream);
 359         }
 360     }
 361   fprintf_filtered (stream, "}");
 362 }
 363
 364 /* Special val_print routine to avoid printing multiple copies of virtual
 365    baseclasses.  */
 366
 367 static void
 368 cplus_print_value (type, valaddr, stream, format, recurse, pretty, dont_print)
 369      struct type *type;
 370      char *valaddr;
 371      GDB_FILE *stream;
 372      int format;
 373      int recurse;
 374      enum val_prettyprint pretty;
 375      struct type **dont_print;
 376 {
 377   struct obstack tmp_obstack;
 378   struct type **last_dont_print
 379     = (struct type **)obstack_next_free (&dont_print_obstack);
 380   int i, n_baseclasses = TYPE_N_BASECLASSES (type);
 381
 382   if (dont_print == 0)
 383     {
 384       /* If we're at top level, carve out a completely fresh
 385          chunk of the obstack and use that until this particular
 386          invocation returns.  */
 387       tmp_obstack = dont_print_obstack;
 388       /* Bump up the high-water mark.  Now alpha is omega.  */
 389       obstack_finish (&dont_print_obstack);
 390     }
 391
 392   for (i = 0; i < n_baseclasses; i++)
 393     {
 394       /* FIXME-32x64--assumes that a target pointer can fit in a char *.
 395          Fix it by nuking baseclass_addr.  */
 396       char *baddr;
 397       int err;
 398       char *basename;
 399
 400       check_stub_type (TYPE_BASECLASS (type, i));
 401       basename = TYPE_NAME (TYPE_BASECLASS (type, i));
 402
 403       if (BASETYPE_VIA_VIRTUAL (type, i))
 404         {
 405           struct type **first_dont_print
 406             = (struct type **)obstack_base (&dont_print_obstack);
 407
 408           int j = (struct type **)obstack_next_free (&dont_print_obstack)
 409             - first_dont_print;
 410
 411           while (--j >= 0)
 412             if (TYPE_BASECLASS (type, i) == first_dont_print[j])
 413               goto flush_it;
 414
 415           obstack_ptr_grow (&dont_print_obstack, TYPE_BASECLASS (type, i));
 416         }
 417
 418       /* Fix to use baseclass_offset instead. FIXME */
 419       baddr = baseclass_addr (type, i, valaddr, 0, &err);
 420       if (err == 0 && baddr == 0)
 421         error ("could not find virtual baseclass %s\n",
 422                basename ? basename : "");
 423
 424       if (pretty)
 425         {
 426           fprintf_filtered (stream, "\n");
 427           print_spaces_filtered (2 * recurse, stream);
 428         }
 429       fputs_filtered ("<", stream);
 430       /* Not sure what the best notation is in the case where there is no
 431          baseclass name.  */
 432       fputs_filtered (basename ? basename : "", stream);
 433       fputs_filtered ("> = ", stream);
 434       if (err != 0)
 435         {
 436           fprintf_filtered (stream, "<invalid address ");
 437           print_address_numeric ((CORE_ADDR) baddr, 1, stream);
 438           fprintf_filtered (stream, ">");
 439         }
 440       else
 441         cp_print_value_fields (TYPE_BASECLASS (type, i), baddr, stream, format,
 442                                recurse, pretty,
 443                                (struct type **) obstack_base (&dont_print_obstack));
 444       fputs_filtered (", ", stream);
 445
 446     flush_it:
 447       ;
 448     }
 449
 450   if (dont_print == 0)
 451     {
 452       /* Free the space used to deal with the printing
 453          of this type from top level.  */
 454       obstack_free (&dont_print_obstack, last_dont_print);
 455       /* Reset watermark so that we can continue protecting
 456          ourselves from whatever we were protecting ourselves.  */
 457       dont_print_obstack = tmp_obstack;
 458     }
 459 }
 460
 461 void
 462 cp_print_class_member (valaddr, domain, stream, prefix)
 463      char *valaddr;
 464      struct type *domain;
 465      GDB_FILE *stream;
 466      char *prefix;
 467 {
 468
 469   /* VAL is a byte offset into the structure type DOMAIN.
 470      Find the name of the field for that offset and
 471      print it.  */
 472   int extra = 0;
 473   int bits = 0;
 474   register unsigned int i;
 475   unsigned len = TYPE_NFIELDS (domain);
 476   /* @@ Make VAL into bit offset */
 477   LONGEST val = unpack_long (builtin_type_int, valaddr) << 3;
 478   for (i = TYPE_N_BASECLASSES (domain); i < len; i++)
 479     {
 480       int bitpos = TYPE_FIELD_BITPOS (domain, i);
 481       QUIT;
 482       if (val == bitpos)
 483         break;
 484       if (val < bitpos && i != 0)
 485         {
 486           /* Somehow pointing into a field.  */
 487           i -= 1;
 488           extra = (val - TYPE_FIELD_BITPOS (domain, i));
 489           if (extra & 0x7)
 490             bits = 1;
 491           else
 492             extra >>= 3;
 493           break;
 494         }
 495     }
 496   if (i < len)
 497     {
 498       char *name;
 499       fprintf_filtered (stream, prefix);
 500       name = type_name_no_tag (domain);
 501       if (name)
 502         fputs_filtered (name, stream);
 503       else
 504         c_type_print_base (domain, stream, 0, 0);
 505       fprintf_filtered (stream, "::");
 506       fputs_filtered (TYPE_FIELD_NAME (domain, i), stream);
 507       if (extra)
 508         fprintf_filtered (stream, " + %d bytes", extra);
 509       if (bits)
 510         fprintf_filtered (stream, " (offset in bits)");
 511     }
 512   else
 513     fprintf_filtered (stream, "%d", val >> 3);
 514 }
 515
 516 void
 517 _initialize_cp_valprint ()
 518 {
 519   add_show_from_set
 520     (add_set_cmd ("static-members", class_support, var_boolean,
 521                   (char *)&static_field_print,
 522                   "Set printing of C++ static members.",
 523                   &setprintlist),
 524      &showprintlist);
 525   /* Turn on printing of static fields.  */
 526   static_field_print = 1;
 527
 528   add_show_from_set
 529     (add_set_cmd ("vtbl", class_support, var_boolean, (char *)&vtblprint,
 530                   "Set printing of C++ virtual function tables.",
 531                   &setprintlist),
 532      &showprintlist);
 533
 534   add_show_from_set
 535     (add_set_cmd ("object", class_support, var_boolean, (char *)&objectprint,
 536           "Set printing of object's derived type based on vtable info.",
 537                   &setprintlist),
 538      &showprintlist);
 539
 540   /* Give people the defaults which they are used to.  */
 541   objectprint = 0;
 542   vtblprint = 0;
 543   obstack_begin (&dont_print_obstack, 32 * sizeof (struct type *));
 544 }