gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2017 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 = (const struct typedef_field *) 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 = (const struct typedef_field *) a;
 102   const struct typedef_field *tfb = (const struct typedef_field *) 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 ((struct typedef_hash_table *) 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 = (htab_t) 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 = (struct type_print_options *) 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 = (struct typedef_field *) *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
 301         = (const char *) obstack_copy0 (&flags->global_typedefs->storage,
 302                                         applied, 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 = (struct typedef_field *) htab_find (flags->local_typedefs->table,
 324                                                   &tf);
 325
 326       if (found != NULL)
 327         return found->name;
 328     }
 329
 330   return find_global_typedef (flags, t);
 331 }
 332
 333 \f
 334
 335 /* Print a description of a type in the format of a
 336    typedef for the current language.
 337    NEW is the new name for a type TYPE.  */
 338
 339 void
 340 typedef_print (struct type *type, struct symbol *newobj, struct ui_file *stream)
 341 {
 342   LA_PRINT_TYPEDEF (type, newobj, stream);
 343 }
 344
 345 /* The default way to print a typedef.  */
 346
 347 void
 348 default_print_typedef (struct type *type, struct symbol *new_symbol,
 349                        struct ui_file *stream)
 350 {
 351   error (_("Language not supported."));
 352 }
 353
 354 /* Print a description of a type TYPE in the form of a declaration of a
 355    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
 356    Output goes to STREAM (via stdio).
 357    If SHOW is positive, we show the contents of the outermost level
 358    of structure even if there is a type name that could be used instead.
 359    If SHOW is negative, we never show the details of elements' types.  */
 360
 361 void
 362 type_print (struct type *type, const char *varstring, struct ui_file *stream,
 363             int show)
 364 {
 365   LA_PRINT_TYPE (type, varstring, stream, show, 0, &default_ptype_flags);
 366 }
 367
 368 /* Print TYPE to a string, returning it.  The caller is responsible for
 369    freeing the string.  */
 370
 371 std::string
 372 type_to_string (struct type *type)
 373 {
 374   std::string s;
 375   struct ui_file *stb;
 376   struct cleanup *old_chain;
 377
 378   stb = mem_fileopen ();
 379   old_chain = make_cleanup_ui_file_delete (stb);
 380
 381   TRY
 382     {
 383       type_print (type, "", stb, -1);
 384       s = ui_file_as_string (stb);
 385     }
 386   CATCH (except, RETURN_MASK_ALL)
 387     {
 388     }
 389   END_CATCH
 390
 391   do_cleanups (old_chain);
 392
 393   return s;
 394 }
 395
 396 /* Print type of EXP, or last thing in value history if EXP == NULL.
 397    show is passed to type_print.  */
 398
 399 static void
 400 whatis_exp (char *exp, int show)
 401 {
 402   struct value *val;
 403   struct cleanup *old_chain;
 404   struct type *real_type = NULL;
 405   struct type *type;
 406   int full = 0;
 407   LONGEST top = -1;
 408   int using_enc = 0;
 409   struct value_print_options opts;
 410   struct type_print_options flags = default_ptype_flags;
 411
 412   old_chain = make_cleanup (null_cleanup, NULL);
 413
 414   if (exp)
 415     {
 416       if (*exp == '/')
 417         {
 418           int seen_one = 0;
 419
 420           for (++exp; *exp && !isspace (*exp); ++exp)
 421             {
 422               switch (*exp)
 423                 {
 424                 case 'r':
 425                   flags.raw = 1;
 426                   break;
 427                 case 'm':
 428                   flags.print_methods = 0;
 429                   break;
 430                 case 'M':
 431                   flags.print_methods = 1;
 432                   break;
 433                 case 't':
 434                   flags.print_typedefs = 0;
 435                   break;
 436                 case 'T':
 437                   flags.print_typedefs = 1;
 438                   break;
 439                 default:
 440                   error (_("unrecognized flag '%c'"), *exp);
 441                 }
 442               seen_one = 1;
 443             }
 444
 445           if (!*exp && !seen_one)
 446             error (_("flag expected"));
 447           if (!isspace (*exp))
 448             error (_("expected space after format"));
 449           exp = skip_spaces (exp);
 450         }
 451
 452       expression_up expr = parse_expression (exp);
 453       val = evaluate_type (expr.get ());
 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_STRUCT))
 466         real_type = value_rtti_indirect_type (val, &full, &top, &using_enc);
 467       else if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
 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 *type_name, int from_tty)
 504 {
 505   whatis_exp (type_name, 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   type = 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 *type_name, int from_tty)
 597 {
 598   struct value *val;
 599   struct type *type;
 600
 601   if (type_name != NULL)
 602     {
 603       expression_up expr = parse_expression (type_name);
 604       if (expr->elts[0].opcode == OP_TYPE)
 605         {
 606           /* The user expression names a type directly, just use that type.  */
 607           type = expr->elts[1].type;
 608         }
 609       else
 610         {
 611           /* The user expression may name a type indirectly by naming an
 612              object of that type.  Find that indirectly named type.  */
 613           val = evaluate_type (expr.get ());
 614           type = value_type (val);
 615         }
 616       if (type != NULL)
 617         {
 618           recursive_dump_type (type, 0);
 619         }
 620     }
 621 }
 622 \f
 623
 624 struct cmd_list_element *setprinttypelist;
 625
 626 struct cmd_list_element *showprinttypelist;
 627
 628 static void
 629 set_print_type (char *arg, int from_tty)
 630 {
 631   printf_unfiltered (
 632      "\"set print type\" must be followed by the name of a subcommand.\n");
 633   help_list (setprintlist, "set print type ", all_commands, gdb_stdout);
 634 }
 635
 636 static void
 637 show_print_type (char *args, int from_tty)
 638 {
 639   cmd_show_list (showprinttypelist, from_tty, "");
 640 }
 641
 642 static int print_methods = 1;
 643
 644 static void
 645 set_print_type_methods (char *args, int from_tty, struct cmd_list_element *c)
 646 {
 647   default_ptype_flags.print_methods = print_methods;
 648 }
 649
 650 static void
 651 show_print_type_methods (struct ui_file *file, int from_tty,
 652                          struct cmd_list_element *c, const char *value)
 653 {
 654   fprintf_filtered (file, _("Printing of methods defined in a class in %s\n"),
 655                     value);
 656 }
 657
 658 static int print_typedefs = 1;
 659
 660 static void
 661 set_print_type_typedefs (char *args, int from_tty, struct cmd_list_element *c)
 662 {
 663   default_ptype_flags.print_typedefs = print_typedefs;
 664 }
 665
 666 static void
 667 show_print_type_typedefs (struct ui_file *file, int from_tty,
 668                          struct cmd_list_element *c, const char *value)
 669 {
 670   fprintf_filtered (file, _("Printing of typedefs defined in a class in %s\n"),
 671                     value);
 672 }
 673
 674 void
 675 _initialize_typeprint (void)
 676 {
 677   struct cmd_list_element *c;
 678
 679   c = add_com ("ptype", class_vars, ptype_command, _("\
 680 Print definition of type TYPE.\n\
 681 Usage: ptype[/FLAGS] TYPE | EXPRESSION\n\
 682 Argument may be any type (for example a type name defined by typedef,\n\
 683 or \"struct STRUCT-TAG\" or \"class CLASS-NAME\" or \"union UNION-TAG\"\n\
 684 or \"enum ENUM-TAG\") or an expression.\n\
 685 The selected stack frame's lexical context is used to look up the name.\n\
 686 Contrary to \"whatis\", \"ptype\" always unrolls any typedefs.\n\
 687 \n\
 688 Available FLAGS are:\n\
 689   /r    print in \"raw\" form; do not substitute typedefs\n\
 690   /m    do not print methods defined in a class\n\
 691   /M    print methods defined in a class\n\
 692   /t    do not print typedefs defined in a class\n\
 693   /T    print typedefs defined in a class"));
 694   set_cmd_completer (c, expression_completer);
 695
 696   c = add_com ("whatis", class_vars, whatis_command,
 697                _("Print data type of expression EXP.\n\
 698 Only one level of typedefs is unrolled.  See also \"ptype\"."));
 699   set_cmd_completer (c, expression_completer);
 700
 701   add_prefix_cmd ("type", no_class, show_print_type,
 702                   _("Generic command for showing type-printing settings."),
 703                   &showprinttypelist, "show print type ", 0, &showprintlist);
 704   add_prefix_cmd ("type", no_class, set_print_type,
 705                   _("Generic command for setting how types print."),
 706                   &setprinttypelist, "show print type ", 0, &setprintlist);
 707
 708   add_setshow_boolean_cmd ("methods", no_class, &print_methods,
 709                            _("\
 710 Set printing of methods defined in classes."), _("\
 711 Show printing of methods defined in classes."), NULL,
 712                            set_print_type_methods,
 713                            show_print_type_methods,
 714                            &setprinttypelist, &showprinttypelist);
 715   add_setshow_boolean_cmd ("typedefs", no_class, &print_typedefs,
 716                            _("\
 717 Set printing of typedefs defined in classes."), _("\
 718 Show printing of typedefs defined in classes."), NULL,
 719                            set_print_type_typedefs,
 720                            show_print_type_typedefs,
 721                            &setprinttypelist, &showprinttypelist);
 722 }
 723
 724 /* Print <not allocated> status to stream STREAM.  */
 725
 726 void
 727 val_print_not_allocated (struct ui_file *stream)
 728 {
 729   fprintf_filtered (stream, _("<not allocated>"));
 730 }
 731
 732 /* Print <not associated> status to stream STREAM.  */
 733
 734 void
 735 val_print_not_associated (struct ui_file *stream)
 736 {
 737   fprintf_filtered (stream, _("<not associated>"));
 738 }
 739