gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2015 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 "valprint.h"
  35 #include <ctype.h>
  36 #include "cli/cli-utils.h"
  37 #include "extension.h"
  38 #include "completer.h"
  39
  40 extern void _initialize_typeprint (void);
  41
  42 static void ptype_command (char *, int);
  43
  44 static void whatis_command (char *, int);
  45
  46 static void whatis_exp (char *, int);
  47
  48 const struct type_print_options type_print_raw_options =
  49 {
  50   1,                            /* raw */
  51   1,                            /* print_methods */
  52   1,                            /* print_typedefs */
  53   NULL,                         /* local_typedefs */
  54   NULL,                         /* global_table */
  55   NULL                          /* global_printers */
  56 };
  57
  58 /* The default flags for 'ptype' and 'whatis'.  */
  59
  60 static struct type_print_options default_ptype_flags =
  61 {
  62   0,                            /* raw */
  63   1,                            /* print_methods */
  64   1,                            /* print_typedefs */
  65   NULL,                         /* local_typedefs */
  66   NULL,                         /* global_table */
  67   NULL                          /* global_printers */
  68 };
  69
  70 \f
  71
  72 /* A hash table holding typedef_field objects.  This is more
  73    complicated than an ordinary hash because it must also track the
  74    lifetime of some -- but not all -- of the contained objects.  */
  75
  76 struct typedef_hash_table
  77 {
  78   /* The actual hash table.  */
  79   htab_t table;
  80
  81   /* Storage for typedef_field objects that must be synthesized.  */
  82   struct obstack storage;
  83 };
  84
  85 /* A hash function for a typedef_field.  */
  86
  87 static hashval_t
  88 hash_typedef_field (const void *p)
  89 {
  90   const struct typedef_field *tf = p;
  91   struct type *t = check_typedef (tf->type);
  92
  93   return htab_hash_string (TYPE_SAFE_NAME (t));
  94 }
  95
  96 /* An equality function for a typedef field.  */
  97
  98 static int
  99 eq_typedef_field (const void *a, const void *b)
 100 {
 101   const struct typedef_field *tfa = a;
 102   const struct typedef_field *tfb = b;
 103
 104   return types_equal (tfa->type, tfb->type);
 105 }
 106
 107 /* Add typedefs from T to the hash table TABLE.  */
 108
 109 void
 110 recursively_update_typedef_hash (struct typedef_hash_table *table,
 111                                  struct type *t)
 112 {
 113   int i;
 114
 115   if (table == NULL)
 116     return;
 117
 118   for (i = 0; i < TYPE_TYPEDEF_FIELD_COUNT (t); ++i)
 119     {
 120       struct typedef_field *tdef = &TYPE_TYPEDEF_FIELD (t, i);
 121       void **slot;
 122
 123       slot = htab_find_slot (table->table, tdef, INSERT);
 124       /* Only add a given typedef name once.  Really this shouldn't
 125          happen; but it is safe enough to do the updates breadth-first
 126          and thus use the most specific typedef.  */
 127       if (*slot == NULL)
 128         *slot = tdef;
 129     }
 130
 131   /* Recurse into superclasses.  */
 132   for (i = 0; i < TYPE_N_BASECLASSES (t); ++i)
 133     recursively_update_typedef_hash (table, TYPE_BASECLASS (t, i));
 134 }
 135
 136 /* Add template parameters from T to the typedef hash TABLE.  */
 137
 138 void
 139 add_template_parameters (struct typedef_hash_table *table, struct type *t)
 140 {
 141   int i;
 142
 143   if (table == NULL)
 144     return;
 145
 146   for (i = 0; i < TYPE_N_TEMPLATE_ARGUMENTS (t); ++i)
 147     {
 148       struct typedef_field *tf;
 149       void **slot;
 150
 151       /* We only want type-valued template parameters in the hash.  */
 152       if (SYMBOL_CLASS (TYPE_TEMPLATE_ARGUMENT (t, i)) != LOC_TYPEDEF)
 153         continue;
 154
 155       tf = XOBNEW (&table->storage, struct typedef_field);
 156       tf->name = SYMBOL_LINKAGE_NAME (TYPE_TEMPLATE_ARGUMENT (t, i));
 157       tf->type = SYMBOL_TYPE (TYPE_TEMPLATE_ARGUMENT (t, i));
 158
 159       slot = htab_find_slot (table->table, tf, INSERT);
 160       if (*slot == NULL)
 161         *slot = tf;
 162     }
 163 }
 164
 165 /* Create a new typedef-lookup hash table.  */
 166
 167 struct typedef_hash_table *
 168 create_typedef_hash (void)
 169 {
 170   struct typedef_hash_table *result;
 171
 172   result = XNEW (struct typedef_hash_table);
 173   result->table = htab_create_alloc (10, hash_typedef_field, eq_typedef_field,
 174                                      NULL, xcalloc, xfree);
 175   obstack_init (&result->storage);
 176
 177   return result;
 178 }
 179
 180 /* Free a typedef field table.  */
 181
 182 void
 183 free_typedef_hash (struct typedef_hash_table *table)
 184 {
 185   if (table != NULL)
 186     {
 187       htab_delete (table->table);
 188       obstack_free (&table->storage, NULL);
 189       xfree (table);
 190     }
 191 }
 192
 193 /* A cleanup for freeing a typedef_hash_table.  */
 194
 195 static void
 196 do_free_typedef_hash (void *arg)
 197 {
 198   free_typedef_hash (arg);
 199 }
 200
 201 /* Return a new cleanup that frees TABLE.  */
 202
 203 struct cleanup *
 204 make_cleanup_free_typedef_hash (struct typedef_hash_table *table)
 205 {
 206   return make_cleanup (do_free_typedef_hash, table);
 207 }
 208
 209 /* Helper function for copy_typedef_hash.  */
 210
 211 static int
 212 copy_typedef_hash_element (void **slot, void *nt)
 213 {
 214   htab_t new_table = nt;
 215   void **new_slot;
 216
 217   new_slot = htab_find_slot (new_table, *slot, INSERT);
 218   if (*new_slot == NULL)
 219     *new_slot = *slot;
 220
 221   return 1;
 222 }
 223
 224 /* Copy a typedef hash.  */
 225
 226 struct typedef_hash_table *
 227 copy_typedef_hash (struct typedef_hash_table *table)
 228 {
 229   struct typedef_hash_table *result;
 230
 231   if (table == NULL)
 232     return NULL;
 233
 234   result = create_typedef_hash ();
 235   htab_traverse_noresize (table->table, copy_typedef_hash_element,
 236                           result->table);
 237   return result;
 238 }
 239
 240 /* A cleanup to free the global typedef hash.  */
 241
 242 static void
 243 do_free_global_table (void *arg)
 244 {
 245   struct type_print_options *flags = arg;
 246
 247   free_typedef_hash (flags->global_typedefs);
 248   free_ext_lang_type_printers (flags->global_printers);
 249 }
 250
 251 /* Create the global typedef hash.  */
 252
 253 static struct cleanup *
 254 create_global_typedef_table (struct type_print_options *flags)
 255 {
 256   gdb_assert (flags->global_typedefs == NULL && flags->global_printers == NULL);
 257   flags->global_typedefs = create_typedef_hash ();
 258   flags->global_printers = start_ext_lang_type_printers ();
 259   return make_cleanup (do_free_global_table, flags);
 260 }
 261
 262 /* Look up the type T in the global typedef hash.  If it is found,
 263    return the typedef name.  If it is not found, apply the
 264    type-printers, if any, given by start_script_type_printers and return the
 265    result.  A NULL return means that the name was not found.  */
 266
 267 static const char *
 268 find_global_typedef (const struct type_print_options *flags,
 269                      struct type *t)
 270 {
 271   char *applied;
 272   void **slot;
 273   struct typedef_field tf, *new_tf;
 274
 275   if (flags->global_typedefs == NULL)
 276     return NULL;
 277
 278   tf.name = NULL;
 279   tf.type = t;
 280
 281   slot = htab_find_slot (flags->global_typedefs->table, &tf, INSERT);
 282   if (*slot != NULL)
 283     {
 284       new_tf = *slot;
 285       return new_tf->name;
 286     }
 287
 288   /* Put an entry into the hash table now, in case
 289      apply_ext_lang_type_printers recurses.  */
 290   new_tf = XOBNEW (&flags->global_typedefs->storage, struct typedef_field);
 291   new_tf->name = NULL;
 292   new_tf->type = t;
 293
 294   *slot = new_tf;
 295
 296   applied = apply_ext_lang_type_printers (flags->global_printers, t);
 297
 298   if (applied != NULL)
 299     {
 300       new_tf->name = obstack_copy0 (&flags->global_typedefs->storage, applied,
 301                                     strlen (applied));
 302       xfree (applied);
 303     }
 304
 305   return new_tf->name;
 306 }
 307
 308 /* Look up the type T in the typedef hash table in with FLAGS.  If T
 309    is in the table, return its short (class-relative) typedef name.
 310    Otherwise return NULL.  If the table is NULL, this always returns
 311    NULL.  */
 312
 313 const char *
 314 find_typedef_in_hash (const struct type_print_options *flags, struct type *t)
 315 {
 316   if (flags->local_typedefs != NULL)
 317     {
 318       struct typedef_field tf, *found;
 319
 320       tf.name = NULL;
 321       tf.type = t;
 322       found = htab_find (flags->local_typedefs->table, &tf);
 323
 324       if (found != NULL)
 325         return found->name;
 326     }
 327
 328   return find_global_typedef (flags, t);
 329 }
 330
 331 \f
 332
 333 /* Print a description of a type in the format of a
 334    typedef for the current language.
 335    NEW is the new name for a type TYPE.  */
 336
 337 void
 338 typedef_print (struct type *type, struct symbol *new, struct ui_file *stream)
 339 {
 340   LA_PRINT_TYPEDEF (type, new, stream);
 341 }
 342
 343 /* The default way to print a typedef.  */
 344
 345 void
 346 default_print_typedef (struct type *type, struct symbol *new_symbol,
 347                        struct ui_file *stream)
 348 {
 349   error (_("Language not supported."));
 350 }
 351
 352 /* Print a description of a type TYPE in the form of a declaration of a
 353    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
 354    Output goes to STREAM (via stdio).
 355    If SHOW is positive, we show the contents of the outermost level
 356    of structure even if there is a type name that could be used instead.
 357    If SHOW is negative, we never show the details of elements' types.  */
 358
 359 void
 360 type_print (struct type *type, const char *varstring, struct ui_file *stream,
 361             int show)
 362 {
 363   LA_PRINT_TYPE (type, varstring, stream, show, 0, &default_ptype_flags);
 364 }
 365
 366 /* Print TYPE to a string, returning it.  The caller is responsible for
 367    freeing the string.  */
 368
 369 char *
 370 type_to_string (struct type *type)
 371 {
 372   char *s = NULL;
 373   struct ui_file *stb;
 374   struct cleanup *old_chain;
 375   volatile struct gdb_exception except;
 376
 377   stb = mem_fileopen ();
 378   old_chain = make_cleanup_ui_file_delete (stb);
 379
 380   TRY_CATCH (except, RETURN_MASK_ALL)
 381     {
 382       type_print (type, "", stb, -1);
 383       s = ui_file_xstrdup (stb, NULL);
 384     }
 385   if (except.reason < 0)
 386     s = NULL;
 387
 388   do_cleanups (old_chain);
 389
 390   return s;
 391 }
 392
 393 /* Print type of EXP, or last thing in value history if EXP == NULL.
 394    show is passed to type_print.  */
 395
 396 static void
 397 whatis_exp (char *exp, int show)
 398 {
 399   struct expression *expr;
 400   struct value *val;
 401   struct cleanup *old_chain;
 402   struct type *real_type = NULL;
 403   struct type *type;
 404   int full = 0;
 405   int top = -1;
 406   int using_enc = 0;
 407   struct value_print_options opts;
 408   struct type_print_options flags = default_ptype_flags;
 409
 410   old_chain = make_cleanup (null_cleanup, NULL);
 411
 412   if (exp)
 413     {
 414       if (*exp == '/')
 415         {
 416           int seen_one = 0;
 417
 418           for (++exp; *exp && !isspace (*exp); ++exp)
 419             {
 420               switch (*exp)
 421                 {
 422                 case 'r':
 423                   flags.raw = 1;
 424                   break;
 425                 case 'm':
 426                   flags.print_methods = 0;
 427                   break;
 428                 case 'M':
 429                   flags.print_methods = 1;
 430                   break;
 431                 case 't':
 432                   flags.print_typedefs = 0;
 433                   break;
 434                 case 'T':
 435                   flags.print_typedefs = 1;
 436                   break;
 437                 default:
 438                   error (_("unrecognized flag '%c'"), *exp);
 439                 }
 440               seen_one = 1;
 441             }
 442
 443           if (!*exp && !seen_one)
 444             error (_("flag expected"));
 445           if (!isspace (*exp))
 446             error (_("expected space after format"));
 447           exp = skip_spaces (exp);
 448         }
 449
 450       expr = parse_expression (exp);
 451       make_cleanup (free_current_contents, &expr);
 452       val = evaluate_type (expr);
 453     }
 454   else
 455     val = access_value_history (0);
 456
 457   type = value_type (val);
 458
 459   get_user_print_options (&opts);
 460   if (opts.objectprint)
 461     {
 462       if (((TYPE_CODE (type) == TYPE_CODE_PTR)
 463            || (TYPE_CODE (type) == TYPE_CODE_REF))
 464           && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_STRUCT))
 465         real_type = value_rtti_indirect_type (val, &full, &top, &using_enc);
 466       else if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
 467         real_type = value_rtti_type (val, &full, &top, &using_enc);
 468     }
 469
 470   printf_filtered ("type = ");
 471
 472   if (!flags.raw)
 473     create_global_typedef_table (&flags);
 474
 475   if (real_type)
 476     {
 477       printf_filtered ("/* real type = ");
 478       type_print (real_type, "", gdb_stdout, -1);
 479       if (! full)
 480         printf_filtered (" (incomplete object)");
 481       printf_filtered (" */\n");
 482     }
 483
 484   LA_PRINT_TYPE (type, "", gdb_stdout, show, 0, &flags);
 485   printf_filtered ("\n");
 486
 487   do_cleanups (old_chain);
 488 }
 489
 490 static void
 491 whatis_command (char *exp, int from_tty)
 492 {
 493   /* Most of the time users do not want to see all the fields
 494      in a structure.  If they do they can use the "ptype" command.
 495      Hence the "-1" below.  */
 496   whatis_exp (exp, -1);
 497 }
 498
 499 /* TYPENAME is either the name of a type, or an expression.  */
 500
 501 static void
 502 ptype_command (char *typename, int from_tty)
 503 {
 504   whatis_exp (typename, 1);
 505 }
 506
 507 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 508    Used to print data from type structures in a specified type.  For example,
 509    array bounds may be characters or booleans in some languages, and this
 510    allows the ranges to be printed in their "natural" form rather than as
 511    decimal integer values.
 512
 513    FIXME:  This is here simply because only the type printing routines
 514    currently use it, and it wasn't clear if it really belonged somewhere
 515    else (like printcmd.c).  There are a lot of other gdb routines that do
 516    something similar, but they are generally concerned with printing values
 517    that come from the inferior in target byte order and target size.  */
 518
 519 void
 520 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 521 {
 522   unsigned int i;
 523   unsigned len;
 524
 525   CHECK_TYPEDEF (type);
 526
 527   switch (TYPE_CODE (type))
 528     {
 529
 530     case TYPE_CODE_ENUM:
 531       len = TYPE_NFIELDS (type);
 532       for (i = 0; i < len; i++)
 533         {
 534           if (TYPE_FIELD_ENUMVAL (type, i) == val)
 535             {
 536               break;
 537             }
 538         }
 539       if (i < len)
 540         {
 541           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 542         }
 543       else
 544         {
 545           print_longest (stream, 'd', 0, val);
 546         }
 547       break;
 548
 549     case TYPE_CODE_INT:
 550       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 551       break;
 552
 553     case TYPE_CODE_CHAR:
 554       LA_PRINT_CHAR ((unsigned char) val, type, stream);
 555       break;
 556
 557     case TYPE_CODE_BOOL:
 558       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 559       break;
 560
 561     case TYPE_CODE_RANGE:
 562       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 563       return;
 564
 565     case TYPE_CODE_UNDEF:
 566     case TYPE_CODE_PTR:
 567     case TYPE_CODE_ARRAY:
 568     case TYPE_CODE_STRUCT:
 569     case TYPE_CODE_UNION:
 570     case TYPE_CODE_FUNC:
 571     case TYPE_CODE_FLT:
 572     case TYPE_CODE_VOID:
 573     case TYPE_CODE_SET:
 574     case TYPE_CODE_STRING:
 575     case TYPE_CODE_ERROR:
 576     case TYPE_CODE_MEMBERPTR:
 577     case TYPE_CODE_METHODPTR:
 578     case TYPE_CODE_METHOD:
 579     case TYPE_CODE_REF:
 580     case TYPE_CODE_NAMESPACE:
 581       error (_("internal error: unhandled type in print_type_scalar"));
 582       break;
 583
 584     default:
 585       error (_("Invalid type code in symbol table."));
 586     }
 587   gdb_flush (stream);
 588 }
 589
 590 /* Dump details of a type specified either directly or indirectly.
 591    Uses the same sort of type lookup mechanism as ptype_command()
 592    and whatis_command().  */
 593
 594 void
 595 maintenance_print_type (char *typename, int from_tty)
 596 {
 597   struct value *val;
 598   struct type *type;
 599   struct cleanup *old_chain;
 600   struct expression *expr;
 601
 602   if (typename != NULL)
 603     {
 604       expr = parse_expression (typename);
 605       old_chain = make_cleanup (free_current_contents, &expr);
 606       if (expr->elts[0].opcode == OP_TYPE)
 607         {
 608           /* The user expression names a type directly, just use that type.  */
 609           type = expr->elts[1].type;
 610         }
 611       else
 612         {
 613           /* The user expression may name a type indirectly by naming an
 614              object of that type.  Find that indirectly named type.  */
 615           val = evaluate_type (expr);
 616           type = value_type (val);
 617         }
 618       if (type != NULL)
 619         {
 620           recursive_dump_type (type, 0);
 621         }
 622       do_cleanups (old_chain);
 623     }
 624 }
 625 \f
 626
 627 struct cmd_list_element *setprinttypelist;
 628
 629 struct cmd_list_element *showprinttypelist;
 630
 631 static void
 632 set_print_type (char *arg, int from_tty)
 633 {
 634   printf_unfiltered (
 635      "\"set print type\" must be followed by the name of a subcommand.\n");
 636   help_list (setprintlist, "set print type ", all_commands, gdb_stdout);
 637 }
 638
 639 static void
 640 show_print_type (char *args, int from_tty)
 641 {
 642   cmd_show_list (showprinttypelist, from_tty, "");
 643 }
 644
 645 static int print_methods = 1;
 646
 647 static void
 648 set_print_type_methods (char *args, int from_tty, struct cmd_list_element *c)
 649 {
 650   default_ptype_flags.print_methods = print_methods;
 651 }
 652
 653 static void
 654 show_print_type_methods (struct ui_file *file, int from_tty,
 655                          struct cmd_list_element *c, const char *value)
 656 {
 657   fprintf_filtered (file, _("Printing of methods defined in a class in %s\n"),
 658                     value);
 659 }
 660
 661 static int print_typedefs = 1;
 662
 663 static void
 664 set_print_type_typedefs (char *args, int from_tty, struct cmd_list_element *c)
 665 {
 666   default_ptype_flags.print_typedefs = print_typedefs;
 667 }
 668
 669 static void
 670 show_print_type_typedefs (struct ui_file *file, int from_tty,
 671                          struct cmd_list_element *c, const char *value)
 672 {
 673   fprintf_filtered (file, _("Printing of typedefs defined in a class in %s\n"),
 674                     value);
 675 }
 676
 677 void
 678 _initialize_typeprint (void)
 679 {
 680   struct cmd_list_element *c;
 681
 682   c = add_com ("ptype", class_vars, ptype_command, _("\
 683 Print definition of type TYPE.\n\
 684 Usage: ptype[/FLAGS] TYPE | EXPRESSION\n\
 685 Argument may be any type (for example a type name defined by typedef,\n\
 686 or \"struct STRUCT-TAG\" or \"class CLASS-NAME\" or \"union UNION-TAG\"\n\
 687 or \"enum ENUM-TAG\") or an expression.\n\
 688 The selected stack frame's lexical context is used to look up the name.\n\
 689 Contrary to \"whatis\", \"ptype\" always unrolls any typedefs.\n\
 690 \n\
 691 Available FLAGS are:\n\
 692   /r    print in \"raw\" form; do not substitute typedefs\n\
 693   /m    do not print methods defined in a class\n\
 694   /M    print methods defined in a class\n\
 695   /t    do not print typedefs defined in a class\n\
 696   /T    print typedefs defined in a class"));
 697   set_cmd_completer (c, expression_completer);
 698
 699   c = add_com ("whatis", class_vars, whatis_command,
 700                _("Print data type of expression EXP.\n\
 701 Only one level of typedefs is unrolled.  See also \"ptype\"."));
 702   set_cmd_completer (c, expression_completer);
 703
 704   add_prefix_cmd ("type", no_class, show_print_type,
 705                   _("Generic command for showing type-printing settings."),
 706                   &showprinttypelist, "show print type ", 0, &showprintlist);
 707   add_prefix_cmd ("type", no_class, set_print_type,
 708                   _("Generic command for setting how types print."),
 709                   &setprinttypelist, "show print type ", 0, &setprintlist);
 710
 711   add_setshow_boolean_cmd ("methods", no_class, &print_methods,
 712                            _("\
 713 Set printing of methods defined in classes."), _("\
 714 Show printing of methods defined in classes."), NULL,
 715                            set_print_type_methods,
 716                            show_print_type_methods,
 717                            &setprinttypelist, &showprinttypelist);
 718   add_setshow_boolean_cmd ("typedefs", no_class, &print_typedefs,
 719                            _("\
 720 Set printing of typedefs defined in classes."), _("\
 721 Show printing of typedefs defined in classes."), NULL,
 722                            set_print_type_typedefs,
 723                            show_print_type_typedefs,
 724                            &setprinttypelist, &showprinttypelist);
 725 }