gdb/c-valprint.c

   1 /* Support for printing C values for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
   4    1998, 1999, 2000, 2001, 2003, 2005, 2006, 2007, 2008
   5    Free Software Foundation, Inc.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "gdb_string.h"
  24 #include "symtab.h"
  25 #include "gdbtypes.h"
  26 #include "expression.h"
  27 #include "value.h"
  28 #include "valprint.h"
  29 #include "language.h"
  30 #include "c-lang.h"
  31 #include "cp-abi.h"
  32 #include "target.h"
  33 \f
  34
  35 /* Print function pointer with inferior address ADDRESS onto stdio
  36    stream STREAM.  */
  37
  38 static void
  39 print_function_pointer_address (CORE_ADDR address, struct ui_file *stream)
  40 {
  41   CORE_ADDR func_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
  42                                                             address,
  43                                                             &current_target);
  44
  45   /* If the function pointer is represented by a description, print the
  46      address of the description.  */
  47   if (addressprint && func_addr != address)
  48     {
  49       fputs_filtered ("@", stream);
  50       fputs_filtered (paddress (address), stream);
  51       fputs_filtered (": ", stream);
  52     }
  53   print_address_demangle (func_addr, stream, demangle);
  54 }
  55
  56
  57 /* Apply a heuristic to decide whether an array of TYPE or a pointer
  58    to TYPE should be printed as a textual string.  Return non-zero if
  59    it should, or zero if it should be treated as an array of integers
  60    or pointer to integers.  FORMAT is the current format letter,
  61    or 0 if none.
  62
  63    We guess that "char" is a character.  Explicitly signed and
  64    unsigned character types are also characters.  Integer data from
  65    vector types is not.  The user can override this by using the /s
  66    format letter.  */
  67
  68 static int
  69 textual_element_type (struct type *type, char format)
  70 {
  71   struct type *true_type = check_typedef (type);
  72
  73   if (format != 0 && format != 's')
  74     return 0;
  75
  76   /* TYPE_CODE_CHAR is always textual.  */
  77   if (TYPE_CODE (true_type) == TYPE_CODE_CHAR)
  78     return 1;
  79
  80   if (format == 's')
  81     {
  82       /* Print this as a string if we can manage it.  For now, no
  83          wide character support.  */
  84       if (TYPE_CODE (true_type) == TYPE_CODE_INT
  85           && TYPE_LENGTH (true_type) == 1)
  86         return 1;
  87     }
  88   else
  89     {
  90       /* If a one-byte TYPE_CODE_INT is missing the not-a-character
  91          flag, then we treat it as text; otherwise, we assume it's
  92          being used as data.  */
  93       if (TYPE_CODE (true_type) == TYPE_CODE_INT
  94           && TYPE_LENGTH (true_type) == 1
  95           && !TYPE_NOTTEXT (true_type))
  96         return 1;
  97     }
  98
  99   return 0;
 100 }
 101
 102
 103 /* Print data of type TYPE located at VALADDR (within GDB), which came from
 104    the inferior at address ADDRESS, onto stdio stream STREAM according to
 105    FORMAT (a letter or 0 for natural format).  The data at VALADDR is in
 106    target byte order.
 107
 108    If the data are a string pointer, returns the number of string characters
 109    printed.
 110
 111    If DEREF_REF is nonzero, then dereference references, otherwise just print
 112    them like pointers.
 113
 114    The PRETTY parameter controls prettyprinting.  */
 115
 116 int
 117 c_val_print (struct type *type, const gdb_byte *valaddr, int embedded_offset,
 118              CORE_ADDR address, struct ui_file *stream, int format,
 119              int deref_ref, int recurse, enum val_prettyprint pretty)
 120 {
 121   unsigned int i = 0;   /* Number of characters printed */
 122   unsigned len;
 123   struct type *elttype;
 124   unsigned eltlen;
 125   LONGEST val;
 126   CORE_ADDR addr;
 127
 128   CHECK_TYPEDEF (type);
 129   switch (TYPE_CODE (type))
 130     {
 131     case TYPE_CODE_ARRAY:
 132       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 133       if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (TYPE_TARGET_TYPE (type)) > 0)
 134         {
 135           eltlen = TYPE_LENGTH (elttype);
 136           len = TYPE_LENGTH (type) / eltlen;
 137           if (prettyprint_arrays)
 138             {
 139               print_spaces_filtered (2 + 2 * recurse, stream);
 140             }
 141
 142           /* Print arrays of textual chars with a string syntax.  */
 143           if (textual_element_type (elttype, format))
 144             {
 145               /* If requested, look for the first null char and only print
 146                  elements up to it.  */
 147               if (stop_print_at_null)
 148                 {
 149                   unsigned int temp_len;
 150
 151                   /* Look for a NULL char. */
 152                   for (temp_len = 0;
 153                        (valaddr + embedded_offset)[temp_len]
 154                        && temp_len < len && temp_len < print_max;
 155                        temp_len++);
 156                   len = temp_len;
 157                 }
 158
 159               LA_PRINT_STRING (stream, valaddr + embedded_offset, len, eltlen, 0);
 160               i = len;
 161             }
 162           else
 163             {
 164               fprintf_filtered (stream, "{");
 165               /* If this is a virtual function table, print the 0th
 166                  entry specially, and the rest of the members normally.  */
 167               if (cp_is_vtbl_ptr_type (elttype))
 168                 {
 169                   i = 1;
 170                   fprintf_filtered (stream, _("%d vtable entries"), len - 1);
 171                 }
 172               else
 173                 {
 174                   i = 0;
 175                 }
 176               val_print_array_elements (type, valaddr + embedded_offset, address, stream,
 177                                      format, deref_ref, recurse, pretty, i);
 178               fprintf_filtered (stream, "}");
 179             }
 180           break;
 181         }
 182       /* Array of unspecified length: treat like pointer to first elt.  */
 183       addr = address;
 184       goto print_unpacked_pointer;
 185
 186     case TYPE_CODE_MEMBERPTR:
 187       if (format)
 188         {
 189           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 190           break;
 191         }
 192       cp_print_class_member (valaddr + embedded_offset, type, stream, "&");
 193       break;
 194
 195     case TYPE_CODE_METHODPTR:
 196       cplus_print_method_ptr (valaddr + embedded_offset, type, stream);
 197       break;
 198
 199     case TYPE_CODE_PTR:
 200       if (format && format != 's')
 201         {
 202           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 203           break;
 204         }
 205       if (vtblprint && cp_is_vtbl_ptr_type (type))
 206         {
 207           /* Print the unmangled name if desired.  */
 208           /* Print vtable entry - we only get here if we ARE using
 209              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_STRUCT.) */
 210           CORE_ADDR addr
 211             = extract_typed_address (valaddr + embedded_offset, type);
 212           print_function_pointer_address (addr, stream);
 213           break;
 214         }
 215       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 216         {
 217           addr = unpack_pointer (type, valaddr + embedded_offset);
 218         print_unpacked_pointer:
 219
 220           if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
 221             {
 222               /* Try to print what function it points to.  */
 223               print_function_pointer_address (addr, stream);
 224               /* Return value is irrelevant except for string pointers.  */
 225               return (0);
 226             }
 227
 228           if (addressprint)
 229             fputs_filtered (paddress (addr), stream);
 230
 231           /* For a pointer to a textual type, also print the string
 232              pointed to, unless pointer is null.  */
 233           /* FIXME: need to handle wchar_t here... */
 234
 235           if (textual_element_type (elttype, format) && addr != 0)
 236             {
 237               i = val_print_string (addr, -1, TYPE_LENGTH (elttype), stream);
 238             }
 239           else if (cp_is_vtbl_member (type))
 240             {
 241               /* print vtbl's nicely */
 242               CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
 243
 244               struct minimal_symbol *msymbol =
 245               lookup_minimal_symbol_by_pc (vt_address);
 246               if ((msymbol != NULL) &&
 247                   (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
 248                 {
 249                   fputs_filtered (" <", stream);
 250                   fputs_filtered (SYMBOL_PRINT_NAME (msymbol), stream);
 251                   fputs_filtered (">", stream);
 252                 }
 253               if (vt_address && vtblprint)
 254                 {
 255                   struct value *vt_val;
 256                   struct symbol *wsym = (struct symbol *) NULL;
 257                   struct type *wtype;
 258                   struct block *block = (struct block *) NULL;
 259                   int is_this_fld;
 260
 261                   if (msymbol != NULL)
 262                     wsym = lookup_symbol (SYMBOL_LINKAGE_NAME (msymbol), block,
 263                                           VAR_DOMAIN, &is_this_fld);
 264
 265                   if (wsym)
 266                     {
 267                       wtype = SYMBOL_TYPE (wsym);
 268                     }
 269                   else
 270                     {
 271                       wtype = TYPE_TARGET_TYPE (type);
 272                     }
 273                   vt_val = value_at (wtype, vt_address);
 274                   common_val_print (vt_val, stream, format,
 275                                     deref_ref, recurse + 1, pretty,
 276                                     current_language);
 277                   if (pretty)
 278                     {
 279                       fprintf_filtered (stream, "\n");
 280                       print_spaces_filtered (2 + 2 * recurse, stream);
 281                     }
 282                 }
 283             }
 284
 285           /* Return number of characters printed, including the terminating
 286              '\0' if we reached the end.  val_print_string takes care including
 287              the terminating '\0' if necessary.  */
 288           return i;
 289         }
 290       break;
 291
 292     case TYPE_CODE_REF:
 293       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 294       if (addressprint)
 295         {
 296           CORE_ADDR addr
 297             = extract_typed_address (valaddr + embedded_offset, type);
 298           fprintf_filtered (stream, "@");
 299           fputs_filtered (paddress (addr), stream);
 300           if (deref_ref)
 301             fputs_filtered (": ", stream);
 302         }
 303       /* De-reference the reference.  */
 304       if (deref_ref)
 305         {
 306           if (TYPE_CODE (elttype) != TYPE_CODE_UNDEF)
 307             {
 308               struct value *deref_val =
 309               value_at
 310               (TYPE_TARGET_TYPE (type),
 311                unpack_pointer (type, valaddr + embedded_offset));
 312               common_val_print (deref_val, stream, format, deref_ref,
 313                                 recurse, pretty, current_language);
 314             }
 315           else
 316             fputs_filtered ("???", stream);
 317         }
 318       break;
 319
 320     case TYPE_CODE_UNION:
 321       if (recurse && !unionprint)
 322         {
 323           fprintf_filtered (stream, "{...}");
 324           break;
 325         }
 326       /* Fall through.  */
 327     case TYPE_CODE_STRUCT:
 328       /*FIXME: Abstract this away */
 329       if (vtblprint && cp_is_vtbl_ptr_type (type))
 330         {
 331           /* Print the unmangled name if desired.  */
 332           /* Print vtable entry - we only get here if NOT using
 333              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_PTR.) */
 334           int offset = (embedded_offset +
 335                         TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
 336           struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
 337           CORE_ADDR addr
 338             = extract_typed_address (valaddr + offset, field_type);
 339
 340           print_function_pointer_address (addr, stream);
 341         }
 342       else
 343         cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream, format,
 344                                recurse, pretty, NULL, 0);
 345       break;
 346
 347     case TYPE_CODE_ENUM:
 348       if (format)
 349         {
 350           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 351           break;
 352         }
 353       len = TYPE_NFIELDS (type);
 354       val = unpack_long (type, valaddr + embedded_offset);
 355       for (i = 0; i < len; i++)
 356         {
 357           QUIT;
 358           if (val == TYPE_FIELD_BITPOS (type, i))
 359             {
 360               break;
 361             }
 362         }
 363       if (i < len)
 364         {
 365           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 366         }
 367       else
 368         {
 369           print_longest (stream, 'd', 0, val);
 370         }
 371       break;
 372
 373     case TYPE_CODE_FLAGS:
 374       if (format)
 375           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 376       else
 377         val_print_type_code_flags (type, valaddr + embedded_offset, stream);
 378       break;
 379
 380     case TYPE_CODE_FUNC:
 381     case TYPE_CODE_METHOD:
 382       if (format)
 383         {
 384           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 385           break;
 386         }
 387       /* FIXME, we should consider, at least for ANSI C language, eliminating
 388          the distinction made between FUNCs and POINTERs to FUNCs.  */
 389       fprintf_filtered (stream, "{");
 390       type_print (type, "", stream, -1);
 391       fprintf_filtered (stream, "} ");
 392       /* Try to print what function it points to, and its address.  */
 393       print_address_demangle (address, stream, demangle);
 394       break;
 395
 396     case TYPE_CODE_BOOL:
 397       format = format ? format : output_format;
 398       if (format)
 399         print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 400       else
 401         {
 402           val = unpack_long (type, valaddr + embedded_offset);
 403           if (val == 0)
 404             fputs_filtered ("false", stream);
 405           else if (val == 1)
 406             fputs_filtered ("true", stream);
 407           else
 408             print_longest (stream, 'd', 0, val);
 409         }
 410       break;
 411
 412     case TYPE_CODE_RANGE:
 413       /* FIXME: create_range_type does not set the unsigned bit in a
 414          range type (I think it probably should copy it from the target
 415          type), so we won't print values which are too large to
 416          fit in a signed integer correctly.  */
 417       /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
 418          print with the target type, though, because the size of our type
 419          and the target type might differ).  */
 420       /* FALLTHROUGH */
 421
 422     case TYPE_CODE_INT:
 423       format = format ? format : output_format;
 424       if (format)
 425         {
 426           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 427         }
 428       else
 429         {
 430           val_print_type_code_int (type, valaddr + embedded_offset, stream);
 431           /* C and C++ has no single byte int type, char is used instead.
 432              Since we don't know whether the value is really intended to
 433              be used as an integer or a character, print the character
 434              equivalent as well.  */
 435           if (textual_element_type (type, format))
 436             {
 437               fputs_filtered (" ", stream);
 438               LA_PRINT_CHAR ((unsigned char) unpack_long (type, valaddr + embedded_offset),
 439                              stream);
 440             }
 441         }
 442       break;
 443
 444     case TYPE_CODE_CHAR:
 445       format = format ? format : output_format;
 446       if (format)
 447         {
 448           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 449         }
 450       else
 451         {
 452           val = unpack_long (type, valaddr + embedded_offset);
 453           if (TYPE_UNSIGNED (type))
 454             fprintf_filtered (stream, "%u", (unsigned int) val);
 455           else
 456             fprintf_filtered (stream, "%d", (int) val);
 457           fputs_filtered (" ", stream);
 458           LA_PRINT_CHAR ((unsigned char) val, stream);
 459         }
 460       break;
 461
 462     case TYPE_CODE_FLT:
 463       if (format)
 464         {
 465           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 466         }
 467       else
 468         {
 469           print_floating (valaddr + embedded_offset, type, stream);
 470         }
 471       break;
 472
 473     case TYPE_CODE_DECFLOAT:
 474       if (format)
 475         print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 476       else
 477         print_decimal_floating (valaddr + embedded_offset, type, stream);
 478       break;
 479
 480     case TYPE_CODE_VOID:
 481       fprintf_filtered (stream, "void");
 482       break;
 483
 484     case TYPE_CODE_ERROR:
 485       fprintf_filtered (stream, _("<error type>"));
 486       break;
 487
 488     case TYPE_CODE_UNDEF:
 489       /* This happens (without TYPE_FLAG_STUB set) on systems which don't use
 490          dbx xrefs (NO_DBX_XREFS in gcc) if a file has a "struct foo *bar"
 491          and no complete type for struct foo in that file.  */
 492       fprintf_filtered (stream, _("<incomplete type>"));
 493       break;
 494
 495     case TYPE_CODE_COMPLEX:
 496       if (format)
 497         print_scalar_formatted (valaddr + embedded_offset,
 498                                 TYPE_TARGET_TYPE (type),
 499                                 format, 0, stream);
 500       else
 501         print_floating (valaddr + embedded_offset, TYPE_TARGET_TYPE (type),
 502                         stream);
 503       fprintf_filtered (stream, " + ");
 504       if (format)
 505         print_scalar_formatted (valaddr + embedded_offset
 506                                 + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 507                                 TYPE_TARGET_TYPE (type),
 508                                 format, 0, stream);
 509       else
 510         print_floating (valaddr + embedded_offset
 511                         + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 512                         TYPE_TARGET_TYPE (type),
 513                         stream);
 514       fprintf_filtered (stream, " * I");
 515       break;
 516
 517     default:
 518       error (_("Invalid C/C++ type code %d in symbol table."), TYPE_CODE (type));
 519     }
 520   gdb_flush (stream);
 521   return (0);
 522 }
 523 \f
 524 int
 525 c_value_print (struct value *val, struct ui_file *stream, int format,
 526                enum val_prettyprint pretty)
 527 {
 528   struct type *type, *real_type;
 529   int full, top, using_enc;
 530
 531   /* If it is a pointer, indicate what it points to.
 532
 533      Print type also if it is a reference.
 534
 535      C++: if it is a member pointer, we will take care
 536      of that when we print it.  */
 537
 538   type = check_typedef (value_type (val));
 539
 540   if (TYPE_CODE (type) == TYPE_CODE_PTR
 541       || TYPE_CODE (type) == TYPE_CODE_REF)
 542     {
 543       /* Hack:  remove (char *) for char strings.  Their
 544          type is indicated by the quoted string anyway.
 545          (Don't use textual_element_type here; quoted strings
 546          are always exactly (char *).  */
 547       if (TYPE_CODE (type) == TYPE_CODE_PTR
 548           && TYPE_NAME (type) == NULL
 549           && TYPE_NAME (TYPE_TARGET_TYPE (type)) != NULL
 550           && strcmp (TYPE_NAME (TYPE_TARGET_TYPE (type)), "char") == 0)
 551         {
 552           /* Print nothing */
 553         }
 554       else if (objectprint && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 555         {
 556
 557           if (TYPE_CODE(type) == TYPE_CODE_REF)
 558             {
 559               /* Copy value, change to pointer, so we don't get an
 560                * error about a non-pointer type in value_rtti_target_type
 561                */
 562               struct value *temparg;
 563               temparg=value_copy(val);
 564               deprecated_set_value_type (temparg, lookup_pointer_type (TYPE_TARGET_TYPE(type)));
 565               val=temparg;
 566             }
 567           /* Pointer to class, check real type of object */
 568           fprintf_filtered (stream, "(");
 569           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 570           if (real_type)
 571             {
 572               /* RTTI entry found */
 573               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 574                 {
 575                   /* create a pointer type pointing to the real type */
 576                   type = lookup_pointer_type (real_type);
 577                 }
 578               else
 579                 {
 580                   /* create a reference type referencing the real type */
 581                   type = lookup_reference_type (real_type);
 582                 }
 583               /* JYG: Need to adjust pointer value. */
 584               /* NOTE: cagney/2005-01-02: THIS IS BOGUS.  */
 585               value_contents_writeable (val)[0] -= top;
 586
 587               /* Note: When we look up RTTI entries, we don't get any
 588                  information on const or volatile attributes */
 589             }
 590           type_print (type, "", stream, -1);
 591           fprintf_filtered (stream, ") ");
 592         }
 593       else
 594         {
 595           /* normal case */
 596           fprintf_filtered (stream, "(");
 597           type_print (value_type (val), "", stream, -1);
 598           fprintf_filtered (stream, ") ");
 599         }
 600     }
 601
 602   if (!value_initialized (val))
 603     fprintf_filtered (stream, " [uninitialized] ");
 604
 605   if (objectprint && (TYPE_CODE (type) == TYPE_CODE_CLASS))
 606     {
 607       /* Attempt to determine real type of object */
 608       real_type = value_rtti_type (val, &full, &top, &using_enc);
 609       if (real_type)
 610         {
 611           /* We have RTTI information, so use it */
 612           val = value_full_object (val, real_type, full, top, using_enc);
 613           fprintf_filtered (stream, "(%s%s) ",
 614                             TYPE_NAME (real_type),
 615                             full ? "" : _(" [incomplete object]"));
 616           /* Print out object: enclosing type is same as real_type if full */
 617           return val_print (value_enclosing_type (val),
 618                             value_contents_all (val), 0,
 619                             VALUE_ADDRESS (val), stream, format, 1, 0,
 620                             pretty, current_language);
 621           /* Note: When we look up RTTI entries, we don't get any information on
 622              const or volatile attributes */
 623         }
 624       else if (type != check_typedef (value_enclosing_type (val)))
 625         {
 626           /* No RTTI information, so let's do our best */
 627           fprintf_filtered (stream, "(%s ?) ",
 628                             TYPE_NAME (value_enclosing_type (val)));
 629           return val_print (value_enclosing_type (val),
 630                             value_contents_all (val), 0,
 631                             VALUE_ADDRESS (val), stream, format, 1, 0,
 632                             pretty, current_language);
 633         }
 634       /* Otherwise, we end up at the return outside this "if" */
 635     }
 636
 637   return val_print (type, value_contents_all (val),
 638                     value_embedded_offset (val),
 639                     VALUE_ADDRESS (val) + value_offset (val),
 640                     stream, format, 1, 0, pretty, current_language);
 641 }