gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2014 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "gdb_obstack.h"
  22 #include "bfd.h"                /* Binary File Description */
  23 #include "symtab.h"
  24 #include "gdbtypes.h"
  25 #include "expression.h"
  26 #include "value.h"
  27 #include "gdbcore.h"
  28 #include "command.h"
  29 #include "gdbcmd.h"
  30 #include "target.h"
  31 #include "language.h"
  32 #include "cp-abi.h"
  33 #include "typeprint.h"
  34 #include "exceptions.h"
  35 #include "valprint.h"
  36 #include <ctype.h>
  37 #include "cli/cli-utils.h"
  38 #include "extension.h"
  39 #include "completer.h"
  40
  41 extern void _initialize_typeprint (void);
  42
  43 static void ptype_command (char *, int);
  44
  45 static void whatis_command (char *, int);
  46
  47 static void whatis_exp (char *, int);
  48
  49 const struct type_print_options type_print_raw_options =
  50 {
  51   1,                            /* raw */
  52   1,                            /* print_methods */
  53   1,                            /* print_typedefs */
  54   NULL,                         /* local_typedefs */
  55   NULL,                         /* global_table */
  56   NULL                          /* global_printers */
  57 };
  58
  59 /* The default flags for 'ptype' and 'whatis'.  */
  60
  61 static struct type_print_options default_ptype_flags =
  62 {
  63   0,                            /* raw */
  64   1,                            /* print_methods */
  65   1,                            /* print_typedefs */
  66   NULL,                         /* local_typedefs */
  67   NULL,                         /* global_table */
  68   NULL                          /* global_printers */
  69 };
  70
  71 \f
  72
  73 /* A hash table holding typedef_field objects.  This is more
  74    complicated than an ordinary hash because it must also track the
  75    lifetime of some -- but not all -- of the contained objects.  */
  76
  77 struct typedef_hash_table
  78 {
  79   /* The actual hash table.  */
  80   htab_t table;
  81
  82   /* Storage for typedef_field objects that must be synthesized.  */
  83   struct obstack storage;
  84 };
  85
  86 /* A hash function for a typedef_field.  */
  87
  88 static hashval_t
  89 hash_typedef_field (const void *p)
  90 {
  91   const struct typedef_field *tf = p;
  92   struct type *t = check_typedef (tf->type);
  93
  94   return htab_hash_string (TYPE_SAFE_NAME (t));
  95 }
  96
  97 /* An equality function for a typedef field.  */
  98
  99 static int
 100 eq_typedef_field (const void *a, const void *b)
 101 {
 102   const struct typedef_field *tfa = a;
 103   const struct typedef_field *tfb = b;
 104
 105   return types_equal (tfa->type, tfb->type);
 106 }
 107
 108 /* Add typedefs from T to the hash table TABLE.  */
 109
 110 void
 111 recursively_update_typedef_hash (struct typedef_hash_table *table,
 112                                  struct type *t)
 113 {
 114   int i;
 115
 116   if (table == NULL)
 117     return;
 118
 119   for (i = 0; i < TYPE_TYPEDEF_FIELD_COUNT (t); ++i)
 120     {
 121       struct typedef_field *tdef = &TYPE_TYPEDEF_FIELD (t, i);
 122       void **slot;
 123
 124       slot = htab_find_slot (table->table, tdef, INSERT);
 125       /* Only add a given typedef name once.  Really this shouldn't
 126          happen; but it is safe enough to do the updates breadth-first
 127          and thus use the most specific typedef.  */
 128       if (*slot == NULL)
 129         *slot = tdef;
 130     }
 131
 132   /* Recurse into superclasses.  */
 133   for (i = 0; i < TYPE_N_BASECLASSES (t); ++i)
 134     recursively_update_typedef_hash (table, TYPE_BASECLASS (t, i));
 135 }
 136
 137 /* Add template parameters from T to the typedef hash TABLE.  */
 138
 139 void
 140 add_template_parameters (struct typedef_hash_table *table, struct type *t)
 141 {
 142   int i;
 143
 144   if (table == NULL)
 145     return;
 146
 147   for (i = 0; i < TYPE_N_TEMPLATE_ARGUMENTS (t); ++i)
 148     {
 149       struct typedef_field *tf;
 150       void **slot;
 151
 152       /* We only want type-valued template parameters in the hash.  */
 153       if (SYMBOL_CLASS (TYPE_TEMPLATE_ARGUMENT (t, i)) != LOC_TYPEDEF)
 154         continue;
 155
 156       tf = XOBNEW (&table->storage, struct typedef_field);
 157       tf->name = SYMBOL_LINKAGE_NAME (TYPE_TEMPLATE_ARGUMENT (t, i));
 158       tf->type = SYMBOL_TYPE (TYPE_TEMPLATE_ARGUMENT (t, i));
 159
 160       slot = htab_find_slot (table->table, tf, INSERT);
 161       if (*slot == NULL)
 162         *slot = tf;
 163     }
 164 }
 165
 166 /* Create a new typedef-lookup hash table.  */
 167
 168 struct typedef_hash_table *
 169 create_typedef_hash (void)
 170 {
 171   struct typedef_hash_table *result;
 172
 173   result = XNEW (struct typedef_hash_table);
 174   result->table = htab_create_alloc (10, hash_typedef_field, eq_typedef_field,
 175                                      NULL, xcalloc, xfree);
 176   obstack_init (&result->storage);
 177
 178   return result;
 179 }
 180
 181 /* Free a typedef field table.  */
 182
 183 void
 184 free_typedef_hash (struct typedef_hash_table *table)
 185 {
 186   if (table != NULL)
 187     {
 188       htab_delete (table->table);
 189       obstack_free (&table->storage, NULL);
 190       xfree (table);
 191     }
 192 }
 193
 194 /* A cleanup for freeing a typedef_hash_table.  */
 195
 196 static void
 197 do_free_typedef_hash (void *arg)
 198 {
 199   free_typedef_hash (arg);
 200 }
 201
 202 /* Return a new cleanup that frees TABLE.  */
 203
 204 struct cleanup *
 205 make_cleanup_free_typedef_hash (struct typedef_hash_table *table)
 206 {
 207   return make_cleanup (do_free_typedef_hash, table);
 208 }
 209
 210 /* Helper function for copy_typedef_hash.  */
 211
 212 static int
 213 copy_typedef_hash_element (void **slot, void *nt)
 214 {
 215   htab_t new_table = nt;
 216   void **new_slot;
 217
 218   new_slot = htab_find_slot (new_table, *slot, INSERT);
 219   if (*new_slot == NULL)
 220     *new_slot = *slot;
 221
 222   return 1;
 223 }
 224
 225 /* Copy a typedef hash.  */
 226
 227 struct typedef_hash_table *
 228 copy_typedef_hash (struct typedef_hash_table *table)
 229 {
 230   struct typedef_hash_table *result;
 231
 232   if (table == NULL)
 233     return NULL;
 234
 235   result = create_typedef_hash ();
 236   htab_traverse_noresize (table->table, copy_typedef_hash_element,
 237                           result->table);
 238   return result;
 239 }
 240
 241 /* A cleanup to free the global typedef hash.  */
 242
 243 static void
 244 do_free_global_table (void *arg)
 245 {
 246   struct type_print_options *flags = arg;
 247
 248   free_typedef_hash (flags->global_typedefs);
 249   free_ext_lang_type_printers (flags->global_printers);
 250 }
 251
 252 /* Create the global typedef hash.  */
 253
 254 static struct cleanup *
 255 create_global_typedef_table (struct type_print_options *flags)
 256 {
 257   gdb_assert (flags->global_typedefs == NULL && flags->global_printers == NULL);
 258   flags->global_typedefs = create_typedef_hash ();
 259   flags->global_printers = start_ext_lang_type_printers ();
 260   return make_cleanup (do_free_global_table, flags);
 261 }
 262
 263 /* Look up the type T in the global typedef hash.  If it is found,
 264    return the typedef name.  If it is not found, apply the
 265    type-printers, if any, given by start_script_type_printers and return the
 266    result.  A NULL return means that the name was not found.  */
 267
 268 static const char *
 269 find_global_typedef (const struct type_print_options *flags,
 270                      struct type *t)
 271 {
 272   char *applied;
 273   void **slot;
 274   struct typedef_field tf, *new_tf;
 275
 276   if (flags->global_typedefs == NULL)
 277     return NULL;
 278
 279   tf.name = NULL;
 280   tf.type = t;
 281
 282   slot = htab_find_slot (flags->global_typedefs->table, &tf, INSERT);
 283   if (*slot != NULL)
 284     {
 285       new_tf = *slot;
 286       return new_tf->name;
 287     }
 288
 289   /* Put an entry into the hash table now, in case apply_script_type_printers
 290      recurses.  */
 291   new_tf = XOBNEW (&flags->global_typedefs->storage, struct typedef_field);
 292   new_tf->name = NULL;
 293   new_tf->type = t;
 294
 295   *slot = new_tf;
 296
 297   applied = apply_ext_lang_type_printers (flags->global_printers, t);
 298
 299   if (applied != NULL)
 300     {
 301       new_tf->name = obstack_copy0 (&flags->global_typedefs->storage, applied,
 302                                     strlen (applied));
 303       xfree (applied);
 304     }
 305
 306   return new_tf->name;
 307 }
 308
 309 /* Look up the type T in the typedef hash table in with FLAGS.  If T
 310    is in the table, return its short (class-relative) typedef name.
 311    Otherwise return NULL.  If the table is NULL, this always returns
 312    NULL.  */
 313
 314 const char *
 315 find_typedef_in_hash (const struct type_print_options *flags, struct type *t)
 316 {
 317   if (flags->local_typedefs != NULL)
 318     {
 319       struct typedef_field tf, *found;
 320
 321       tf.name = NULL;
 322       tf.type = t;
 323       found = htab_find (flags->local_typedefs->table, &tf);
 324
 325       if (found != NULL)
 326         return found->name;
 327     }
 328
 329   return find_global_typedef (flags, t);
 330 }
 331
 332 \f
 333
 334 /* Print a description of a type in the format of a
 335    typedef for the current language.
 336    NEW is the new name for a type TYPE.  */
 337
 338 void
 339 typedef_print (struct type *type, struct symbol *new, struct ui_file *stream)
 340 {
 341   LA_PRINT_TYPEDEF (type, new, stream);
 342 }
 343
 344 /* The default way to print a typedef.  */
 345
 346 void
 347 default_print_typedef (struct type *type, struct symbol *new_symbol,
 348                        struct ui_file *stream)
 349 {
 350   error (_("Language not supported."));
 351 }
 352
 353 /* Print a description of a type TYPE in the form of a declaration of a
 354    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
 355    Output goes to STREAM (via stdio).
 356    If SHOW is positive, we show the contents of the outermost level
 357    of structure even if there is a type name that could be used instead.
 358    If SHOW is negative, we never show the details of elements' types.  */
 359
 360 void
 361 type_print (struct type *type, const char *varstring, struct ui_file *stream,
 362             int show)
 363 {
 364   LA_PRINT_TYPE (type, varstring, stream, show, 0, &default_ptype_flags);
 365 }
 366
 367 /* Print TYPE to a string, returning it.  The caller is responsible for
 368    freeing the string.  */
 369
 370 char *
 371 type_to_string (struct type *type)
 372 {
 373   char *s = NULL;
 374   struct ui_file *stb;
 375   struct cleanup *old_chain;
 376   volatile struct gdb_exception except;
 377
 378   stb = mem_fileopen ();
 379   old_chain = make_cleanup_ui_file_delete (stb);
 380
 381   TRY_CATCH (except, RETURN_MASK_ALL)
 382     {
 383       type_print (type, "", stb, -1);
 384       s = ui_file_xstrdup (stb, NULL);
 385     }
 386   if (except.reason < 0)
 387     s = NULL;
 388
 389   do_cleanups (old_chain);
 390
 391   return s;
 392 }
 393
 394 /* Print type of EXP, or last thing in value history if EXP == NULL.
 395    show is passed to type_print.  */
 396
 397 static void
 398 whatis_exp (char *exp, int show)
 399 {
 400   struct expression *expr;
 401   struct value *val;
 402   struct cleanup *old_chain;
 403   struct type *real_type = NULL;
 404   struct type *type;
 405   int full = 0;
 406   int top = -1;
 407   int using_enc = 0;
 408   struct value_print_options opts;
 409   struct type_print_options flags = default_ptype_flags;
 410
 411   old_chain = make_cleanup (null_cleanup, NULL);
 412
 413   if (exp)
 414     {
 415       if (*exp == '/')
 416         {
 417           int seen_one = 0;
 418
 419           for (++exp; *exp && !isspace (*exp); ++exp)
 420             {
 421               switch (*exp)
 422                 {
 423                 case 'r':
 424                   flags.raw = 1;
 425                   break;
 426                 case 'm':
 427                   flags.print_methods = 0;
 428                   break;
 429                 case 'M':
 430                   flags.print_methods = 1;
 431                   break;
 432                 case 't':
 433                   flags.print_typedefs = 0;
 434                   break;
 435                 case 'T':
 436                   flags.print_typedefs = 1;
 437                   break;
 438                 default:
 439                   error (_("unrecognized flag '%c'"), *exp);
 440                 }
 441               seen_one = 1;
 442             }
 443
 444           if (!*exp && !seen_one)
 445             error (_("flag expected"));
 446           if (!isspace (*exp))
 447             error (_("expected space after format"));
 448           exp = skip_spaces (exp);
 449         }
 450
 451       expr = parse_expression (exp);
 452       make_cleanup (free_current_contents, &expr);
 453       val = evaluate_type (expr);
 454     }
 455   else
 456     val = access_value_history (0);
 457
 458   type = value_type (val);
 459
 460   get_user_print_options (&opts);
 461   if (opts.objectprint)
 462     {
 463       if (((TYPE_CODE (type) == TYPE_CODE_PTR)
 464            || (TYPE_CODE (type) == TYPE_CODE_REF))
 465           && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 466         real_type = value_rtti_indirect_type (val, &full, &top, &using_enc);
 467       else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
 468         real_type = value_rtti_type (val, &full, &top, &using_enc);
 469     }
 470
 471   printf_filtered ("type = ");
 472
 473   if (!flags.raw)
 474     create_global_typedef_table (&flags);
 475
 476   if (real_type)
 477     {
 478       printf_filtered ("/* real type = ");
 479       type_print (real_type, "", gdb_stdout, -1);
 480       if (! full)
 481         printf_filtered (" (incomplete object)");
 482       printf_filtered (" */\n");
 483     }
 484
 485   LA_PRINT_TYPE (type, "", gdb_stdout, show, 0, &flags);
 486   printf_filtered ("\n");
 487
 488   do_cleanups (old_chain);
 489 }
 490
 491 static void
 492 whatis_command (char *exp, int from_tty)
 493 {
 494   /* Most of the time users do not want to see all the fields
 495      in a structure.  If they do they can use the "ptype" command.
 496      Hence the "-1" below.  */
 497   whatis_exp (exp, -1);
 498 }
 499
 500 /* TYPENAME is either the name of a type, or an expression.  */
 501
 502 static void
 503 ptype_command (char *typename, int from_tty)
 504 {
 505   whatis_exp (typename, 1);
 506 }
 507
 508 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 509    Used to print data from type structures in a specified type.  For example,
 510    array bounds may be characters or booleans in some languages, and this
 511    allows the ranges to be printed in their "natural" form rather than as
 512    decimal integer values.
 513
 514    FIXME:  This is here simply because only the type printing routines
 515    currently use it, and it wasn't clear if it really belonged somewhere
 516    else (like printcmd.c).  There are a lot of other gdb routines that do
 517    something similar, but they are generally concerned with printing values
 518    that come from the inferior in target byte order and target size.  */
 519
 520 void
 521 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 522 {
 523   unsigned int i;
 524   unsigned len;
 525
 526   CHECK_TYPEDEF (type);
 527
 528   switch (TYPE_CODE (type))
 529     {
 530
 531     case TYPE_CODE_ENUM:
 532       len = TYPE_NFIELDS (type);
 533       for (i = 0; i < len; i++)
 534         {
 535           if (TYPE_FIELD_ENUMVAL (type, i) == val)
 536             {
 537               break;
 538             }
 539         }
 540       if (i < len)
 541         {
 542           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 543         }
 544       else
 545         {
 546           print_longest (stream, 'd', 0, val);
 547         }
 548       break;
 549
 550     case TYPE_CODE_INT:
 551       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 552       break;
 553
 554     case TYPE_CODE_CHAR:
 555       LA_PRINT_CHAR ((unsigned char) val, type, stream);
 556       break;
 557
 558     case TYPE_CODE_BOOL:
 559       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 560       break;
 561
 562     case TYPE_CODE_RANGE:
 563       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 564       return;
 565
 566     case TYPE_CODE_UNDEF:
 567     case TYPE_CODE_PTR:
 568     case TYPE_CODE_ARRAY:
 569     case TYPE_CODE_STRUCT:
 570     case TYPE_CODE_UNION:
 571     case TYPE_CODE_FUNC:
 572     case TYPE_CODE_FLT:
 573     case TYPE_CODE_VOID:
 574     case TYPE_CODE_SET:
 575     case TYPE_CODE_STRING:
 576     case TYPE_CODE_ERROR:
 577     case TYPE_CODE_MEMBERPTR:
 578     case TYPE_CODE_METHODPTR:
 579     case TYPE_CODE_METHOD:
 580     case TYPE_CODE_REF:
 581     case TYPE_CODE_NAMESPACE:
 582       error (_("internal error: unhandled type in print_type_scalar"));
 583       break;
 584
 585     default:
 586       error (_("Invalid type code in symbol table."));
 587     }
 588   gdb_flush (stream);
 589 }
 590
 591 /* Dump details of a type specified either directly or indirectly.
 592    Uses the same sort of type lookup mechanism as ptype_command()
 593    and whatis_command().  */
 594
 595 void
 596 maintenance_print_type (char *typename, int from_tty)
 597 {
 598   struct value *val;
 599   struct type *type;
 600   struct cleanup *old_chain;
 601   struct expression *expr;
 602
 603   if (typename != NULL)
 604     {
 605       expr = parse_expression (typename);
 606       old_chain = make_cleanup (free_current_contents, &expr);
 607       if (expr->elts[0].opcode == OP_TYPE)
 608         {
 609           /* The user expression names a type directly, just use that type.  */
 610           type = expr->elts[1].type;
 611         }
 612       else
 613         {
 614           /* The user expression may name a type indirectly by naming an
 615              object of that type.  Find that indirectly named type.  */
 616           val = evaluate_type (expr);
 617           type = value_type (val);
 618         }
 619       if (type != NULL)
 620         {
 621           recursive_dump_type (type, 0);
 622         }
 623       do_cleanups (old_chain);
 624     }
 625 }
 626 \f
 627
 628 struct cmd_list_element *setprinttypelist;
 629
 630 struct cmd_list_element *showprinttypelist;
 631
 632 static void
 633 set_print_type (char *arg, int from_tty)
 634 {
 635   printf_unfiltered (
 636      "\"set print type\" must be followed by the name of a subcommand.\n");
 637   help_list (setprintlist, "set print type ", all_commands, gdb_stdout);
 638 }
 639
 640 static void
 641 show_print_type (char *args, int from_tty)
 642 {
 643   cmd_show_list (showprinttypelist, from_tty, "");
 644 }
 645
 646 static int print_methods = 1;
 647
 648 static void
 649 set_print_type_methods (char *args, int from_tty, struct cmd_list_element *c)
 650 {
 651   default_ptype_flags.print_methods = print_methods;
 652 }
 653
 654 static void
 655 show_print_type_methods (struct ui_file *file, int from_tty,
 656                          struct cmd_list_element *c, const char *value)
 657 {
 658   fprintf_filtered (file, _("Printing of methods defined in a class in %s\n"),
 659                     value);
 660 }
 661
 662 static int print_typedefs = 1;
 663
 664 static void
 665 set_print_type_typedefs (char *args, int from_tty, struct cmd_list_element *c)
 666 {
 667   default_ptype_flags.print_typedefs = print_typedefs;
 668 }
 669
 670 static void
 671 show_print_type_typedefs (struct ui_file *file, int from_tty,
 672                          struct cmd_list_element *c, const char *value)
 673 {
 674   fprintf_filtered (file, _("Printing of typedefs defined in a class in %s\n"),
 675                     value);
 676 }
 677
 678 void
 679 _initialize_typeprint (void)
 680 {
 681   struct cmd_list_element *c;
 682
 683   c = add_com ("ptype", class_vars, ptype_command, _("\
 684 Print definition of type TYPE.\n\
 685 Usage: ptype[/FLAGS] TYPE | EXPRESSION\n\
 686 Argument may be any type (for example a type name defined by typedef,\n\
 687 or \"struct STRUCT-TAG\" or \"class CLASS-NAME\" or \"union UNION-TAG\"\n\
 688 or \"enum ENUM-TAG\") or an expression.\n\
 689 The selected stack frame's lexical context is used to look up the name.\n\
 690 Contrary to \"whatis\", \"ptype\" always unrolls any typedefs.\n\
 691 \n\
 692 Available FLAGS are:\n\
 693   /r    print in \"raw\" form; do not substitute typedefs\n\
 694   /m    do not print methods defined in a class\n\
 695   /M    print methods defined in a class\n\
 696   /t    do not print typedefs defined in a class\n\
 697   /T    print typedefs defined in a class"));
 698   set_cmd_completer (c, expression_completer);
 699
 700   c = add_com ("whatis", class_vars, whatis_command,
 701                _("Print data type of expression EXP.\n\
 702 Only one level of typedefs is unrolled.  See also \"ptype\"."));
 703   set_cmd_completer (c, expression_completer);
 704
 705   add_prefix_cmd ("type", no_class, show_print_type,
 706                   _("Generic command for showing type-printing settings."),
 707                   &showprinttypelist, "show print type ", 0, &showprintlist);
 708   add_prefix_cmd ("type", no_class, set_print_type,
 709                   _("Generic command for setting how types print."),
 710                   &setprinttypelist, "show print type ", 0, &setprintlist);
 711
 712   add_setshow_boolean_cmd ("methods", no_class, &print_methods,
 713                            _("\
 714 Set printing of methods defined in classes."), _("\
 715 Show printing of methods defined in classes."), NULL,
 716                            set_print_type_methods,
 717                            show_print_type_methods,
 718                            &setprinttypelist, &showprinttypelist);
 719   add_setshow_boolean_cmd ("typedefs", no_class, &print_typedefs,
 720                            _("\
 721 Set printing of typedefs defined in classes."), _("\
 722 Show printing of typedefs defined in classes."), NULL,
 723                            set_print_type_typedefs,
 724                            show_print_type_typedefs,
 725                            &setprinttypelist, &showprinttypelist);
 726 }