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 /* This was what it was for gcc 2.4.5 and earlier.  */
 154 static const char vtbl_ptr_name_old[] =
 155   { CPLUS_MARKER,'v','t','b','l','_','p','t','r','_','t','y','p','e', 0 };
 156 /* It was changed to this after 2.4.5.  */
 157 const char vtbl_ptr_name[] =
 158   { '_','_','v','t','b','l','_','p','t','r','_','t','y','p','e', 0 };
 159
 160 /* Return truth value for assertion that TYPE is of the type
 161    "pointer to virtual function".  */
 162
 163 int
 164 cp_is_vtbl_ptr_type(type)
 165      struct type *type;
 166 {
 167   char *typename = type_name_no_tag (type);
 168
 169   return (typename != NULL
 170           && (STREQ (typename, vtbl_ptr_name)
 171               || STREQ (typename, vtbl_ptr_name_old)));
 172 }
 173
 174 /* Return truth value for the assertion that TYPE is of the type
 175    "pointer to virtual function table".  */
 176
 177 int
 178 cp_is_vtbl_member(type)
 179      struct type *type;
 180 {
 181   if (TYPE_CODE (type) == TYPE_CODE_PTR)
 182     {
 183       type = TYPE_TARGET_TYPE (type);
 184       if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
 185         {
 186           type = TYPE_TARGET_TYPE (type);
 187           if (TYPE_CODE (type) == TYPE_CODE_STRUCT /* if not using thunks */
 188               || TYPE_CODE (type) == TYPE_CODE_PTR) /* if using thunks */
 189             {
 190               /* Virtual functions tables are full of pointers
 191                  to virtual functions. */
 192               return cp_is_vtbl_ptr_type (type);
 193             }
 194         }
 195     }
 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      GDB_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               if (annotation_level > 1)
 287                 {
 288                   printf_filtered ("\n\032\032field-begin ");
 289                   print_value_flags (TYPE_FIELD_TYPE (type, i));
 290                   printf_filtered ("\n");
 291                 }
 292
 293               fprintf_symbol_filtered (stream, TYPE_FIELD_NAME (type, i),
 294                                        language_cplus,
 295                                        DMGL_PARAMS | DMGL_ANSI);
 296               if (annotation_level > 1)
 297                 printf_filtered ("\n\032\032field-name-end\n");
 298               fputs_filtered (" = ", stream);
 299               if (annotation_level > 1)
 300                 printf_filtered ("\n\032\032field-value\n");
 301             }
 302
 303           if (TYPE_FIELD_PACKED (type, i))
 304             {
 305               value_ptr v;
 306
 307               /* Bitfields require special handling, especially due to byte
 308                  order problems.  */
 309               if (TYPE_FIELD_IGNORE (type, i))
 310                 {
 311                    fputs_filtered ("<optimized out or zero length>", stream);
 312                 }
 313               else
 314                 {
 315                    v = value_from_longest (TYPE_FIELD_TYPE (type, i),
 316                                    unpack_field_as_long (type, valaddr, i));
 317
 318                    val_print (TYPE_FIELD_TYPE(type, i), VALUE_CONTENTS (v), 0,
 319                               stream, format, 0, recurse + 1, pretty);
 320                 }
 321             }
 322           else
 323             {
 324               if (TYPE_FIELD_IGNORE (type, i))
 325                 {
 326                    fputs_filtered ("<optimized out or zero length>", stream);
 327                 }
 328               else
 329                 {
 330                    val_print (TYPE_FIELD_TYPE (type, i),
 331                               valaddr + TYPE_FIELD_BITPOS (type, i) / 8,
 332                               0, stream, format, 0, recurse + 1, pretty);
 333                 }
 334             }
 335           if (annotation_level > 1)
 336             printf_filtered ("\n\032\032field-end\n");
 337         }
 338
 339       if (pretty)
 340         {
 341           fprintf_filtered (stream, "\n");
 342           print_spaces_filtered (2 * recurse, stream);
 343         }
 344     }
 345   fprintf_filtered (stream, "}");
 346 }
 347
 348 /* Special val_print routine to avoid printing multiple copies of virtual
 349    baseclasses.  */
 350
 351 static void
 352 cplus_print_value (type, valaddr, stream, format, recurse, pretty, dont_print)
 353      struct type *type;
 354      char *valaddr;
 355      GDB_FILE *stream;
 356      int format;
 357      int recurse;
 358      enum val_prettyprint pretty;
 359      struct type **dont_print;
 360 {
 361   struct obstack tmp_obstack;
 362   struct type **last_dont_print
 363     = (struct type **)obstack_next_free (&dont_print_obstack);
 364   int i, n_baseclasses = TYPE_N_BASECLASSES (type);
 365
 366   if (dont_print == 0)
 367     {
 368       /* If we're at top level, carve out a completely fresh
 369          chunk of the obstack and use that until this particular
 370          invocation returns.  */
 371       tmp_obstack = dont_print_obstack;
 372       /* Bump up the high-water mark.  Now alpha is omega.  */
 373       obstack_finish (&dont_print_obstack);
 374     }
 375
 376   for (i = 0; i < n_baseclasses; i++)
 377     {
 378       /* FIXME-32x64--assumes that a target pointer can fit in a char *.
 379          Fix it by nuking baseclass_addr.  */
 380       char *baddr;
 381       int err;
 382       char *basename;
 383
 384       check_stub_type (TYPE_BASECLASS (type, i));
 385       basename = TYPE_NAME (TYPE_BASECLASS (type, i));
 386
 387       if (BASETYPE_VIA_VIRTUAL (type, i))
 388         {
 389           struct type **first_dont_print
 390             = (struct type **)obstack_base (&dont_print_obstack);
 391
 392           int j = (struct type **)obstack_next_free (&dont_print_obstack)
 393             - first_dont_print;
 394
 395           while (--j >= 0)
 396             if (TYPE_BASECLASS (type, i) == first_dont_print[j])
 397               goto flush_it;
 398
 399           obstack_ptr_grow (&dont_print_obstack, TYPE_BASECLASS (type, i));
 400         }
 401
 402       /* Fix to use baseclass_offset instead. FIXME */
 403       baddr = baseclass_addr (type, i, valaddr, 0, &err);
 404       if (err == 0 && baddr == 0)
 405         error ("could not find virtual baseclass %s\n",
 406                basename ? basename : "");
 407
 408       if (pretty)
 409         {
 410           fprintf_filtered (stream, "\n");
 411           print_spaces_filtered (2 * recurse, stream);
 412         }
 413       fputs_filtered ("<", stream);
 414       /* Not sure what the best notation is in the case where there is no
 415          baseclass name.  */
 416       fputs_filtered (basename ? basename : "", stream);
 417       fputs_filtered ("> = ", stream);
 418       if (err != 0)
 419         {
 420           fprintf_filtered (stream, "<invalid address ");
 421           print_address_numeric ((CORE_ADDR) baddr, 1, stream);
 422           fprintf_filtered (stream, ">");
 423         }
 424       else
 425         cp_print_value_fields (TYPE_BASECLASS (type, i), baddr, stream, format,
 426                                recurse, pretty,
 427                                (struct type **) obstack_base (&dont_print_obstack));
 428       fputs_filtered (", ", stream);
 429
 430     flush_it:
 431       ;
 432     }
 433
 434   if (dont_print == 0)
 435     {
 436       /* Free the space used to deal with the printing
 437          of this type from top level.  */
 438       obstack_free (&dont_print_obstack, last_dont_print);
 439       /* Reset watermark so that we can continue protecting
 440          ourselves from whatever we were protecting ourselves.  */
 441       dont_print_obstack = tmp_obstack;
 442     }
 443 }
 444
 445 void
 446 cp_print_class_member (valaddr, domain, stream, prefix)
 447      char *valaddr;
 448      struct type *domain;
 449      GDB_FILE *stream;
 450      char *prefix;
 451 {
 452
 453   /* VAL is a byte offset into the structure type DOMAIN.
 454      Find the name of the field for that offset and
 455      print it.  */
 456   int extra = 0;
 457   int bits = 0;
 458   register unsigned int i;
 459   unsigned len = TYPE_NFIELDS (domain);
 460   /* @@ Make VAL into bit offset */
 461   LONGEST val = unpack_long (builtin_type_int, valaddr) << 3;
 462   for (i = TYPE_N_BASECLASSES (domain); i < len; i++)
 463     {
 464       int bitpos = TYPE_FIELD_BITPOS (domain, i);
 465       QUIT;
 466       if (val == bitpos)
 467         break;
 468       if (val < bitpos && i != 0)
 469         {
 470           /* Somehow pointing into a field.  */
 471           i -= 1;
 472           extra = (val - TYPE_FIELD_BITPOS (domain, i));
 473           if (extra & 0x7)
 474             bits = 1;
 475           else
 476             extra >>= 3;
 477           break;
 478         }
 479     }
 480   if (i < len)
 481     {
 482       char *name;
 483       fprintf_filtered (stream, prefix);
 484       name = type_name_no_tag (domain);
 485       if (name)
 486         fputs_filtered (name, stream);
 487       else
 488         c_type_print_base (domain, stream, 0, 0);
 489       fprintf_filtered (stream, "::");
 490       fputs_filtered (TYPE_FIELD_NAME (domain, i), stream);
 491       if (extra)
 492         fprintf_filtered (stream, " + %d bytes", extra);
 493       if (bits)
 494         fprintf_filtered (stream, " (offset in bits)");
 495     }
 496   else
 497     fprintf_filtered (stream, "%d", val >> 3);
 498 }
 499
 500 void
 501 _initialize_cp_valprint ()
 502 {
 503   add_show_from_set
 504     (add_set_cmd ("vtbl", class_support, var_boolean, (char *)&vtblprint,
 505                   "Set printing of C++ virtual function tables.",
 506                   &setprintlist),
 507      &showprintlist);
 508
 509   add_show_from_set
 510     (add_set_cmd ("object", class_support, var_boolean, (char *)&objectprint,
 511           "Set printing of object's derived type based on vtable info.",
 512                   &setprintlist),
 513      &showprintlist);
 514
 515   /* Give people the defaults which they are used to.  */
 516   objectprint = 0;
 517   vtblprint = 0;
 518   obstack_begin (&dont_print_obstack, 32 * sizeof (struct type *));
 519 }