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