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
  56 /* BEGIN-FIXME:  Hooks into c-valprint.c */
  57
  58 extern int
  59 c_val_print PARAMS ((struct type *, char *, CORE_ADDR, GDB_FILE *, int, int, int,
  60                      enum val_prettyprint));
  61 /* END-FIXME */
  62
  63
  64 void
  65 cp_print_class_method (valaddr, type, stream)
  66      char *valaddr;
  67      struct type *type;
  68      GDB_FILE *stream;
  69 {
  70   struct type *domain;
  71   struct fn_field *f = NULL;
  72   int j = 0;
  73   int len2;
  74   int offset;
  75   char *kind = "";
  76   CORE_ADDR addr;
  77   struct symbol *sym;
  78   unsigned len;
  79   unsigned int i;
  80
  81   check_stub_type (TYPE_TARGET_TYPE (type));
  82   domain = TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (type));
  83   if (domain == (struct type *)NULL)
  84     {
  85       fprintf_filtered (stream, "<unknown>");
  86       return;
  87     }
  88   addr = unpack_pointer (lookup_pointer_type (builtin_type_void), valaddr);
  89   if (METHOD_PTR_IS_VIRTUAL (addr))
  90     {
  91       offset = METHOD_PTR_TO_VOFFSET (addr);
  92       len = TYPE_NFN_FIELDS (domain);
  93       for (i = 0; i < len; i++)
  94         {
  95           f = TYPE_FN_FIELDLIST1 (domain, i);
  96           len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i);
  97
  98           for (j = 0; j < len2; j++)
  99             {
 100               QUIT;
 101               if (TYPE_FN_FIELD_VOFFSET (f, j) == offset)
 102                 {
 103                   kind = "virtual ";
 104                   goto common;
 105                 }
 106             }
 107         }
 108     }
 109   else
 110     {
 111       sym = find_pc_function (addr);
 112       if (sym == 0)
 113         {
 114           error ("invalid pointer to member function");
 115         }
 116       len = TYPE_NFN_FIELDS (domain);
 117       for (i = 0; i < len; i++)
 118         {
 119           f = TYPE_FN_FIELDLIST1 (domain, i);
 120           len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i);
 121
 122           for (j = 0; j < len2; j++)
 123             {
 124               QUIT;
 125               if (TYPE_FN_FIELD_STUB (f, j))
 126                 check_stub_method (domain, i, j);
 127               if (STREQ (SYMBOL_NAME (sym), TYPE_FN_FIELD_PHYSNAME (f, j)))
 128                 {
 129                   goto common;
 130                 }
 131             }
 132         }
 133     }
 134   common:
 135   if (i < len)
 136     {
 137       fprintf_filtered (stream, "&");
 138       c_type_print_varspec_prefix (TYPE_FN_FIELD_TYPE (f, j), stream, 0, 0);
 139       fprintf_unfiltered (stream, kind);
 140       if (TYPE_FN_FIELD_PHYSNAME (f, j)[0] == '_'
 141           && TYPE_FN_FIELD_PHYSNAME (f, j)[1] == CPLUS_MARKER)
 142         {
 143           cp_type_print_method_args (TYPE_FN_FIELD_ARGS (f, j) + 1, "~",
 144                                      TYPE_FN_FIELDLIST_NAME (domain, i),
 145                                      0, stream);
 146         }
 147       else
 148         {
 149           cp_type_print_method_args (TYPE_FN_FIELD_ARGS (f, j), "",
 150                                      TYPE_FN_FIELDLIST_NAME (domain, i),
 151                                      0, stream);
 152         }
 153     }
 154   else
 155     {
 156       fprintf_filtered (stream, "(");
 157       type_print (type, "", stream, -1);
 158       fprintf_filtered (stream, ") %d", (int) addr >> 3);
 159     }
 160 }
 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   /* This was what it was for gcc 2.4.5 and earlier.  */
 171   static const char vtbl_ptr_name_old[] =
 172     { CPLUS_MARKER,'v','t','b','l','_','p','t','r','_','t','y','p','e', 0 };
 173   /* It was changed to this after 2.4.5.  */
 174   static const char vtbl_ptr_name[] =
 175     { '_','_','v','t','b','l','_','p','t','r','_','t','y','p','e', 0 };
 176
 177   return (typename != NULL
 178           && (STREQ (typename, vtbl_ptr_name)
 179               || STREQ (typename, vtbl_ptr_name_old)));
 180 }
 181
 182 /* Return truth value for the assertion that TYPE is of the type
 183    "pointer to virtual function table".  */
 184
 185 int
 186 cp_is_vtbl_member(type)
 187      struct type *type;
 188 {
 189   if (TYPE_CODE (type) == TYPE_CODE_PTR)
 190     type = TYPE_TARGET_TYPE (type);
 191   else
 192     return 0;
 193
 194   if (TYPE_CODE (type) == TYPE_CODE_ARRAY
 195       && TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_STRUCT)
 196     /* Virtual functions tables are full of pointers to virtual functions.  */
 197     return cp_is_vtbl_ptr_type (TYPE_TARGET_TYPE (type));
 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           /* Check if static field */
 245           if (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               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 278                                        language_cplus,
 279                                        DMGL_PARAMS | DMGL_ANSI);
 280               fputs_filtered ("\" \"", stream);
 281               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 282                                        language_cplus,
 283                                        DMGL_PARAMS | DMGL_ANSI);
 284               fputs_filtered ("\") \"", stream);
 285             }
 286           else
 287             {
 288               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 289                                        language_cplus,
 290                                        DMGL_PARAMS | DMGL_ANSI);
 291               fputs_filtered (" = ", stream);
 292             }
 293           if (TYPE_FIELD_PACKED (type, i))
 294             {
 295               value v;
 296
 297               /* Bitfields require special handling, especially due to byte
 298                  order problems.  */
 299               v = value_from_longest (TYPE_FIELD_TYPE (type, i),
 300                                    unpack_field_as_long (type, valaddr, i));
 301
 302               c_val_print (TYPE_FIELD_TYPE (type, i), VALUE_CONTENTS (v), 0,
 303                            stream, format, 0, recurse + 1, pretty);
 304             }
 305           else
 306             {
 307               c_val_print (TYPE_FIELD_TYPE (type, i),
 308                            valaddr + TYPE_FIELD_BITPOS (type, i) / 8,
 309                            0, stream, format, 0, recurse + 1, pretty);
 310             }
 311         }
 312       if (pretty)
 313         {
 314           fprintf_filtered (stream, "\n");
 315           print_spaces_filtered (2 * recurse, stream);
 316         }
 317     }
 318   fprintf_filtered (stream, "}");
 319 }
 320
 321 /* Special val_print routine to avoid printing multiple copies of virtual
 322    baseclasses.  */
 323
 324 static void
 325 cplus_print_value (type, valaddr, stream, format, recurse, pretty, dont_print)
 326      struct type *type;
 327      char *valaddr;
 328      GDB_FILE *stream;
 329      int format;
 330      int recurse;
 331      enum val_prettyprint pretty;
 332      struct type **dont_print;
 333 {
 334   struct obstack tmp_obstack;
 335   struct type **last_dont_print
 336     = (struct type **)obstack_next_free (&dont_print_obstack);
 337   int i, n_baseclasses = TYPE_N_BASECLASSES (type);
 338
 339   if (dont_print == 0)
 340     {
 341       /* If we're at top level, carve out a completely fresh
 342          chunk of the obstack and use that until this particular
 343          invocation returns.  */
 344       tmp_obstack = dont_print_obstack;
 345       /* Bump up the high-water mark.  Now alpha is omega.  */
 346       obstack_finish (&dont_print_obstack);
 347     }
 348
 349   for (i = 0; i < n_baseclasses; i++)
 350     {
 351       char *baddr;
 352       int err;
 353       char *basename = TYPE_NAME (TYPE_BASECLASS (type, i));
 354
 355       if (BASETYPE_VIA_VIRTUAL (type, i))
 356         {
 357           struct type **first_dont_print
 358             = (struct type **)obstack_base (&dont_print_obstack);
 359
 360           int j = (struct type **)obstack_next_free (&dont_print_obstack)
 361             - first_dont_print;
 362
 363           while (--j >= 0)
 364             if (TYPE_BASECLASS (type, i) == first_dont_print[j])
 365               goto flush_it;
 366
 367           obstack_ptr_grow (&dont_print_obstack, TYPE_BASECLASS (type, i));
 368         }
 369
 370       /* Fix to use baseclass_offset instead. FIXME */
 371       baddr = baseclass_addr (type, i, valaddr, 0, &err);
 372       if (err == 0 && baddr == 0)
 373         error ("could not find virtual baseclass %s\n",
 374                basename ? basename : "");
 375
 376       if (pretty)
 377         {
 378           fprintf_filtered (stream, "\n");
 379           print_spaces_filtered (2 * recurse, stream);
 380         }
 381       fputs_filtered ("<", stream);
 382       /* Not sure what the best notation is in the case where there is no
 383          baseclass name.  */
 384       fputs_filtered (basename ? basename : "", stream);
 385       fputs_filtered ("> = ", stream);
 386       if (err != 0)
 387         fprintf_filtered (stream,
 388                           "<invalid address 0x%lx>", (unsigned long) baddr);
 389       else
 390         cp_print_value_fields (TYPE_BASECLASS (type, i), baddr, stream, format,
 391                                recurse, pretty,
 392                                (struct type **) obstack_base (&dont_print_obstack));
 393       fputs_filtered (", ", stream);
 394
 395     flush_it:
 396       ;
 397     }
 398
 399   if (dont_print == 0)
 400     {
 401       /* Free the space used to deal with the printing
 402          of this type from top level.  */
 403       obstack_free (&dont_print_obstack, last_dont_print);
 404       /* Reset watermark so that we can continue protecting
 405          ourselves from whatever we were protecting ourselves.  */
 406       dont_print_obstack = tmp_obstack;
 407     }
 408 }
 409
 410 void
 411 cp_print_class_member (valaddr, domain, stream, prefix)
 412      char *valaddr;
 413      struct type *domain;
 414      GDB_FILE *stream;
 415      char *prefix;
 416 {
 417
 418   /* VAL is a byte offset into the structure type DOMAIN.
 419      Find the name of the field for that offset and
 420      print it.  */
 421   int extra = 0;
 422   int bits = 0;
 423   register unsigned int i;
 424   unsigned len = TYPE_NFIELDS (domain);
 425   /* @@ Make VAL into bit offset */
 426   LONGEST val = unpack_long (builtin_type_int, valaddr) << 3;
 427   for (i = TYPE_N_BASECLASSES (domain); i < len; i++)
 428     {
 429       int bitpos = TYPE_FIELD_BITPOS (domain, i);
 430       QUIT;
 431       if (val == bitpos)
 432         break;
 433       if (val < bitpos && i != 0)
 434         {
 435           /* Somehow pointing into a field.  */
 436           i -= 1;
 437           extra = (val - TYPE_FIELD_BITPOS (domain, i));
 438           if (extra & 0x7)
 439             bits = 1;
 440           else
 441             extra >>= 3;
 442           break;
 443         }
 444     }
 445   if (i < len)
 446     {
 447       char *name;
 448       fprintf_filtered (stream, prefix);
 449       name = type_name_no_tag (domain);
 450       if (name)
 451         fputs_filtered (name, stream);
 452       else
 453         c_type_print_base (domain, stream, 0, 0);
 454       fprintf_filtered (stream, "::");
 455       fputs_filtered (TYPE_FIELD_NAME (domain, i), stream);
 456       if (extra)
 457         fprintf_filtered (stream, " + %d bytes", extra);
 458       if (bits)
 459         fprintf_filtered (stream, " (offset in bits)");
 460     }
 461   else
 462     fprintf_filtered (stream, "%d", val >> 3);
 463 }
 464
 465 void
 466 _initialize_cp_valprint ()
 467 {
 468   add_show_from_set
 469     (add_set_cmd ("vtbl", class_support, var_boolean, (char *)&vtblprint,
 470                   "Set printing of C++ virtual function tables.",
 471                   &setprintlist),
 472      &showprintlist);
 473
 474   add_show_from_set
 475     (add_set_cmd ("object", class_support, var_boolean, (char *)&objectprint,
 476           "Set printing of object's derived type based on vtable info.",
 477                   &setprintlist),
 478      &showprintlist);
 479
 480   /* Give people the defaults which they are used to.  */
 481   objectprint = 0;
 482   vtblprint = 0;
 483   obstack_begin (&dont_print_obstack, 32 * sizeof (struct type *));
 484 }