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 *, 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 *, FILE *, int, int));
  43
  44 extern void
  45 c_type_print_varspec_prefix PARAMS ((struct type *, FILE *, int, int));
  46
  47 extern void
  48 cp_type_print_method_args PARAMS ((struct type **, char *, char *, int,
  49                                    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, 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      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 (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 /* WAS this and from 4.10, it changed to __vtbl_ptr_type **
 171   static const char vtbl_ptr_name[] =
 172     { CPLUS_MARKER,'v','t','b','l','_','p','t','r','_','t','y','p','e', 0 };
 173 */
 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 && STREQ(typename, vtbl_ptr_name));
 178 }
 179
 180 /* Return truth value for the assertion that TYPE is of the type
 181    "pointer to virtual function table".  */
 182
 183 int
 184 cp_is_vtbl_member(type)
 185      struct type *type;
 186 {
 187   if (TYPE_CODE (type) == TYPE_CODE_PTR)
 188     type = TYPE_TARGET_TYPE (type);
 189   else
 190     return 0;
 191
 192   if (TYPE_CODE (type) == TYPE_CODE_ARRAY
 193       && TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_STRUCT)
 194     /* Virtual functions tables are full of pointers to virtual functions.  */
 195     return cp_is_vtbl_ptr_type (TYPE_TARGET_TYPE (type));
 196   return 0;
 197 }
 198
 199 /* Mutually recursive subroutines of cplus_print_value and c_val_print to
 200    print out a structure's fields: cp_print_value_fields and cplus_print_value.
 201
 202    TYPE, VALADDR, STREAM, RECURSE, and PRETTY have the
 203    same meanings as in cplus_print_value and c_val_print.
 204
 205    DONT_PRINT is an array of baseclass types that we
 206    should not print, or zero if called from top level.  */
 207
 208 void
 209 cp_print_value_fields (type, valaddr, stream, format, recurse, pretty,
 210                        dont_print)
 211      struct type *type;
 212      char *valaddr;
 213      FILE *stream;
 214      int format;
 215      int recurse;
 216      enum val_prettyprint pretty;
 217      struct type **dont_print;
 218 {
 219   int i, len, n_baseclasses;
 220
 221   check_stub_type (type);
 222
 223   fprintf_filtered (stream, "{");
 224   len = TYPE_NFIELDS (type);
 225   n_baseclasses = TYPE_N_BASECLASSES (type);
 226
 227   /* Print out baseclasses such that we don't print
 228      duplicates of virtual baseclasses.  */
 229   if (n_baseclasses > 0)
 230     cplus_print_value (type, valaddr, stream, format, recurse+1, pretty,
 231                        dont_print);
 232
 233   if (!len && n_baseclasses == 1)
 234     fprintf_filtered (stream, "<No data fields>");
 235   else
 236     {
 237       extern int inspect_it;
 238       int fields_seen = 0;
 239
 240       for (i = n_baseclasses; i < len; i++)
 241         {
 242           /* Check if static field */
 243           if (TYPE_FIELD_STATIC (type, i))
 244             continue;
 245           if (fields_seen)
 246             fprintf_filtered (stream, ", ");
 247           else if (n_baseclasses > 0)
 248             {
 249               if (pretty)
 250                 {
 251                   fprintf_filtered (stream, "\n");
 252                   print_spaces_filtered (2 + 2 * recurse, stream);
 253                   fputs_filtered ("members of ", stream);
 254                   fputs_filtered (type_name_no_tag (type), stream);
 255                   fputs_filtered (": ", stream);
 256                 }
 257             }
 258           fields_seen = 1;
 259
 260           if (pretty)
 261             {
 262               fprintf_filtered (stream, "\n");
 263               print_spaces_filtered (2 + 2 * recurse, stream);
 264             }
 265           else
 266             {
 267               wrap_here (n_spaces (2 + 2 * recurse));
 268             }
 269           if (inspect_it)
 270             {
 271               if (TYPE_CODE (TYPE_FIELD_TYPE (type, i)) == TYPE_CODE_PTR)
 272                 fputs_filtered ("\"( ptr \"", stream);
 273               else
 274                 fputs_filtered ("\"( nodef \"", stream);
 275               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 276                                        language_cplus,
 277                                        DMGL_PARAMS | DMGL_ANSI);
 278               fputs_filtered ("\" \"", stream);
 279               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 280                                        language_cplus,
 281                                        DMGL_PARAMS | DMGL_ANSI);
 282               fputs_filtered ("\") \"", stream);
 283             }
 284           else
 285             {
 286               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 287                                        language_cplus,
 288                                        DMGL_PARAMS | DMGL_ANSI);
 289               fputs_filtered (" = ", stream);
 290             }
 291           if (TYPE_FIELD_PACKED (type, i))
 292             {
 293               value v;
 294
 295               /* Bitfields require special handling, especially due to byte
 296                  order problems.  */
 297               v = value_from_longest (TYPE_FIELD_TYPE (type, i),
 298                                    unpack_field_as_long (type, valaddr, i));
 299
 300               c_val_print (TYPE_FIELD_TYPE (type, i), VALUE_CONTENTS (v), 0,
 301                            stream, format, 0, recurse + 1, pretty);
 302             }
 303           else
 304             {
 305               c_val_print (TYPE_FIELD_TYPE (type, i),
 306                            valaddr + TYPE_FIELD_BITPOS (type, i) / 8,
 307                            0, stream, format, 0, recurse + 1, pretty);
 308             }
 309         }
 310       if (pretty)
 311         {
 312           fprintf_filtered (stream, "\n");
 313           print_spaces_filtered (2 * recurse, stream);
 314         }
 315     }
 316   fprintf_filtered (stream, "}");
 317 }
 318
 319 /* Special val_print routine to avoid printing multiple copies of virtual
 320    baseclasses.  */
 321
 322 static void
 323 cplus_print_value (type, valaddr, stream, format, recurse, pretty, dont_print)
 324      struct type *type;
 325      char *valaddr;
 326      FILE *stream;
 327      int format;
 328      int recurse;
 329      enum val_prettyprint pretty;
 330      struct type **dont_print;
 331 {
 332   struct obstack tmp_obstack;
 333   struct type **last_dont_print
 334     = (struct type **)obstack_next_free (&dont_print_obstack);
 335   int i, n_baseclasses = TYPE_N_BASECLASSES (type);
 336
 337   if (dont_print == 0)
 338     {
 339       /* If we're at top level, carve out a completely fresh
 340          chunk of the obstack and use that until this particular
 341          invocation returns.  */
 342       tmp_obstack = dont_print_obstack;
 343       /* Bump up the high-water mark.  Now alpha is omega.  */
 344       obstack_finish (&dont_print_obstack);
 345     }
 346
 347   for (i = 0; i < n_baseclasses; i++)
 348     {
 349       char *baddr;
 350       int err;
 351       char *basename = TYPE_NAME (TYPE_BASECLASS (type, i));
 352
 353       if (BASETYPE_VIA_VIRTUAL (type, i))
 354         {
 355           struct type **first_dont_print
 356             = (struct type **)obstack_base (&dont_print_obstack);
 357
 358           int j = (struct type **)obstack_next_free (&dont_print_obstack)
 359             - first_dont_print;
 360
 361           while (--j >= 0)
 362             if (TYPE_BASECLASS (type, i) == first_dont_print[j])
 363               goto flush_it;
 364
 365           obstack_ptr_grow (&dont_print_obstack, TYPE_BASECLASS (type, i));
 366         }
 367
 368       /* Fix to use baseclass_offset instead. FIXME */
 369       baddr = baseclass_addr (type, i, valaddr, 0, &err);
 370       if (err == 0 && baddr == 0)
 371         error ("could not find virtual baseclass %s\n",
 372                basename ? basename : "");
 373
 374       if (pretty)
 375         {
 376           fprintf_filtered (stream, "\n");
 377           print_spaces_filtered (2 * recurse, stream);
 378         }
 379       fputs_filtered ("<", stream);
 380       /* Not sure what the best notation is in the case where there is no
 381          baseclass name.  */
 382       fputs_filtered (basename ? basename : "", stream);
 383       fputs_filtered ("> = ", stream);
 384       if (err != 0)
 385         fprintf_filtered (stream,
 386                           "<invalid address 0x%lx>", (unsigned long) baddr);
 387       else
 388         cp_print_value_fields (TYPE_BASECLASS (type, i), baddr, stream, format,
 389                                recurse, pretty,
 390                                (struct type **) obstack_base (&dont_print_obstack));
 391       fputs_filtered (", ", stream);
 392
 393     flush_it:
 394       ;
 395     }
 396
 397   if (dont_print == 0)
 398     {
 399       /* Free the space used to deal with the printing
 400          of this type from top level.  */
 401       obstack_free (&dont_print_obstack, last_dont_print);
 402       /* Reset watermark so that we can continue protecting
 403          ourselves from whatever we were protecting ourselves.  */
 404       dont_print_obstack = tmp_obstack;
 405     }
 406 }
 407
 408 void
 409 cp_print_class_member (valaddr, domain, stream, prefix)
 410      char *valaddr;
 411      struct type *domain;
 412      FILE *stream;
 413      char *prefix;
 414 {
 415
 416   /* VAL is a byte offset into the structure type DOMAIN.
 417      Find the name of the field for that offset and
 418      print it.  */
 419   int extra = 0;
 420   int bits = 0;
 421   register unsigned int i;
 422   unsigned len = TYPE_NFIELDS (domain);
 423   /* @@ Make VAL into bit offset */
 424   LONGEST val = unpack_long (builtin_type_int, valaddr) << 3;
 425   for (i = TYPE_N_BASECLASSES (domain); i < len; i++)
 426     {
 427       int bitpos = TYPE_FIELD_BITPOS (domain, i);
 428       QUIT;
 429       if (val == bitpos)
 430         break;
 431       if (val < bitpos && i != 0)
 432         {
 433           /* Somehow pointing into a field.  */
 434           i -= 1;
 435           extra = (val - TYPE_FIELD_BITPOS (domain, i));
 436           if (extra & 0x7)
 437             bits = 1;
 438           else
 439             extra >>= 3;
 440           break;
 441         }
 442     }
 443   if (i < len)
 444     {
 445       char *name;
 446       fprintf_filtered (stream, prefix);
 447       name = type_name_no_tag (domain);
 448       if (name)
 449         fputs_filtered (name, stream);
 450       else
 451         c_type_print_base (domain, stream, 0, 0);
 452       fprintf_filtered (stream, "::");
 453       fputs_filtered (TYPE_FIELD_NAME (domain, i), stream);
 454       if (extra)
 455         fprintf_filtered (stream, " + %d bytes", extra);
 456       if (bits)
 457         fprintf_filtered (stream, " (offset in bits)");
 458     }
 459   else
 460     fprintf_filtered (stream, "%d", val >> 3);
 461 }
 462
 463 void
 464 _initialize_cp_valprint ()
 465 {
 466   add_show_from_set
 467     (add_set_cmd ("vtbl", class_support, var_boolean, (char *)&vtblprint,
 468                   "Set printing of C++ virtual function tables.",
 469                   &setprintlist),
 470      &showprintlist);
 471
 472   add_show_from_set
 473     (add_set_cmd ("object", class_support, var_boolean, (char *)&objectprint,
 474           "Set printing of object's derived type based on vtable info.",
 475                   &setprintlist),
 476      &showprintlist);
 477
 478   /* Give people the defaults which they are used to.  */
 479   objectprint = 0;
 480   vtblprint = 0;
 481   obstack_begin (&dont_print_obstack, 32 * sizeof (struct type *));
 482 }