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