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
   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 2 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, write to the Free Software
  21    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  22    Boston, MA 02110-1301, USA.  */
  23
  24 #include "defs.h"
  25 #include "gdb_string.h"
  26 #include "symtab.h"
  27 #include "gdbtypes.h"
  28 #include "expression.h"
  29 #include "value.h"
  30 #include "valprint.h"
  31 #include "language.h"
  32 #include "c-lang.h"
  33 #include "cp-abi.h"
  34 #include "target.h"
  35 \f
  36
  37 /* Print function pointer with inferior address ADDRESS onto stdio
  38    stream STREAM.  */
  39
  40 static void
  41 print_function_pointer_address (CORE_ADDR address, struct ui_file *stream)
  42 {
  43   CORE_ADDR func_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
  44                                                             address,
  45                                                             &current_target);
  46
  47   /* If the function pointer is represented by a description, print the
  48      address of the description.  */
  49   if (addressprint && func_addr != address)
  50     {
  51       fputs_filtered ("@", stream);
  52       deprecated_print_address_numeric (address, 1, stream);
  53       fputs_filtered (": ", stream);
  54     }
  55   print_address_demangle (func_addr, stream, demangle);
  56 }
  57
  58
  59 /* Print data of type TYPE located at VALADDR (within GDB), which came from
  60    the inferior at address ADDRESS, onto stdio stream STREAM according to
  61    FORMAT (a letter or 0 for natural format).  The data at VALADDR is in
  62    target byte order.
  63
  64    If the data are a string pointer, returns the number of string characters
  65    printed.
  66
  67    If DEREF_REF is nonzero, then dereference references, otherwise just print
  68    them like pointers.
  69
  70    The PRETTY parameter controls prettyprinting.  */
  71
  72 int
  73 c_val_print (struct type *type, const gdb_byte *valaddr, int embedded_offset,
  74              CORE_ADDR address, struct ui_file *stream, int format,
  75              int deref_ref, int recurse, enum val_prettyprint pretty)
  76 {
  77   unsigned int i = 0;   /* Number of characters printed */
  78   unsigned len;
  79   struct type *elttype;
  80   unsigned eltlen;
  81   LONGEST val;
  82   CORE_ADDR addr;
  83
  84   CHECK_TYPEDEF (type);
  85   switch (TYPE_CODE (type))
  86     {
  87     case TYPE_CODE_ARRAY:
  88       elttype = check_typedef (TYPE_TARGET_TYPE (type));
  89       if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (TYPE_TARGET_TYPE (type)) > 0)
  90         {
  91           eltlen = TYPE_LENGTH (elttype);
  92           len = TYPE_LENGTH (type) / eltlen;
  93           if (prettyprint_arrays)
  94             {
  95               print_spaces_filtered (2 + 2 * recurse, stream);
  96             }
  97           /* For an array of chars, print with string syntax.  */
  98           if (eltlen == 1 &&
  99               ((TYPE_CODE (elttype) == TYPE_CODE_INT)
 100                || ((current_language->la_language == language_m2)
 101                    && (TYPE_CODE (elttype) == TYPE_CODE_CHAR)))
 102               && (format == 0 || format == 's'))
 103             {
 104               /* If requested, look for the first null char and only print
 105                  elements up to it.  */
 106               if (stop_print_at_null)
 107                 {
 108                   unsigned int temp_len;
 109
 110                   /* Look for a NULL char. */
 111                   for (temp_len = 0;
 112                        (valaddr + embedded_offset)[temp_len]
 113                        && temp_len < len && temp_len < print_max;
 114                        temp_len++);
 115                   len = temp_len;
 116                 }
 117
 118               LA_PRINT_STRING (stream, valaddr + embedded_offset, len, eltlen, 0);
 119               i = len;
 120             }
 121           else
 122             {
 123               fprintf_filtered (stream, "{");
 124               /* If this is a virtual function table, print the 0th
 125                  entry specially, and the rest of the members normally.  */
 126               if (cp_is_vtbl_ptr_type (elttype))
 127                 {
 128                   i = 1;
 129                   fprintf_filtered (stream, _("%d vtable entries"), len - 1);
 130                 }
 131               else
 132                 {
 133                   i = 0;
 134                 }
 135               val_print_array_elements (type, valaddr + embedded_offset, address, stream,
 136                                      format, deref_ref, recurse, pretty, i);
 137               fprintf_filtered (stream, "}");
 138             }
 139           break;
 140         }
 141       /* Array of unspecified length: treat like pointer to first elt.  */
 142       addr = address;
 143       goto print_unpacked_pointer;
 144
 145     case TYPE_CODE_MEMBERPTR:
 146       if (format)
 147         {
 148           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 149           break;
 150         }
 151       cp_print_class_member (valaddr + embedded_offset,
 152                              TYPE_DOMAIN_TYPE (type),
 153                              stream, "&");
 154       break;
 155
 156     case TYPE_CODE_METHODPTR:
 157       cplus_print_method_ptr (valaddr + embedded_offset, type, stream);
 158       break;
 159
 160     case TYPE_CODE_PTR:
 161       if (format && format != 's')
 162         {
 163           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 164           break;
 165         }
 166       if (vtblprint && cp_is_vtbl_ptr_type (type))
 167         {
 168           /* Print the unmangled name if desired.  */
 169           /* Print vtable entry - we only get here if we ARE using
 170              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_STRUCT.) */
 171           CORE_ADDR addr
 172             = extract_typed_address (valaddr + embedded_offset, type);
 173           print_function_pointer_address (addr, stream);
 174           break;
 175         }
 176       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 177         {
 178           addr = unpack_pointer (type, valaddr + embedded_offset);
 179         print_unpacked_pointer:
 180
 181           if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
 182             {
 183               /* Try to print what function it points to.  */
 184               print_function_pointer_address (addr, stream);
 185               /* Return value is irrelevant except for string pointers.  */
 186               return (0);
 187             }
 188
 189           if (addressprint && format != 's')
 190             {
 191               deprecated_print_address_numeric (addr, 1, stream);
 192             }
 193
 194           /* For a pointer to char or unsigned char, also print the string
 195              pointed to, unless pointer is null.  */
 196           /* FIXME: need to handle wchar_t here... */
 197
 198           if (TYPE_LENGTH (elttype) == 1
 199               && TYPE_CODE (elttype) == TYPE_CODE_INT
 200               && (format == 0 || format == 's')
 201               && addr != 0)
 202             {
 203               i = val_print_string (addr, -1, TYPE_LENGTH (elttype), stream);
 204             }
 205           else if (cp_is_vtbl_member (type))
 206             {
 207               /* print vtbl's nicely */
 208               CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
 209
 210               struct minimal_symbol *msymbol =
 211               lookup_minimal_symbol_by_pc (vt_address);
 212               if ((msymbol != NULL) &&
 213                   (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
 214                 {
 215                   fputs_filtered (" <", stream);
 216                   fputs_filtered (SYMBOL_PRINT_NAME (msymbol), stream);
 217                   fputs_filtered (">", stream);
 218                 }
 219               if (vt_address && vtblprint)
 220                 {
 221                   struct value *vt_val;
 222                   struct symbol *wsym = (struct symbol *) NULL;
 223                   struct type *wtype;
 224                   struct block *block = (struct block *) NULL;
 225                   int is_this_fld;
 226
 227                   if (msymbol != NULL)
 228                     wsym = lookup_symbol (DEPRECATED_SYMBOL_NAME (msymbol), block,
 229                                           VAR_DOMAIN, &is_this_fld, NULL);
 230
 231                   if (wsym)
 232                     {
 233                       wtype = SYMBOL_TYPE (wsym);
 234                     }
 235                   else
 236                     {
 237                       wtype = TYPE_TARGET_TYPE (type);
 238                     }
 239                   vt_val = value_at (wtype, vt_address);
 240                   common_val_print (vt_val, stream, format,
 241                                     deref_ref, recurse + 1, pretty);
 242                   if (pretty)
 243                     {
 244                       fprintf_filtered (stream, "\n");
 245                       print_spaces_filtered (2 + 2 * recurse, stream);
 246                     }
 247                 }
 248             }
 249
 250           /* Return number of characters printed, including the terminating
 251              '\0' if we reached the end.  val_print_string takes care including
 252              the terminating '\0' if necessary.  */
 253           return i;
 254         }
 255       break;
 256
 257     case TYPE_CODE_REF:
 258       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 259       if (addressprint)
 260         {
 261           CORE_ADDR addr
 262             = extract_typed_address (valaddr + embedded_offset, type);
 263           fprintf_filtered (stream, "@");
 264           deprecated_print_address_numeric (addr, 1, stream);
 265           if (deref_ref)
 266             fputs_filtered (": ", stream);
 267         }
 268       /* De-reference the reference.  */
 269       if (deref_ref)
 270         {
 271           if (TYPE_CODE (elttype) != TYPE_CODE_UNDEF)
 272             {
 273               struct value *deref_val =
 274               value_at
 275               (TYPE_TARGET_TYPE (type),
 276                unpack_pointer (lookup_pointer_type (builtin_type_void),
 277                                valaddr + embedded_offset));
 278               common_val_print (deref_val, stream, format, deref_ref,
 279                                 recurse, pretty);
 280             }
 281           else
 282             fputs_filtered ("???", stream);
 283         }
 284       break;
 285
 286     case TYPE_CODE_UNION:
 287       if (recurse && !unionprint)
 288         {
 289           fprintf_filtered (stream, "{...}");
 290           break;
 291         }
 292       /* Fall through.  */
 293     case TYPE_CODE_STRUCT:
 294       /*FIXME: Abstract this away */
 295       if (vtblprint && cp_is_vtbl_ptr_type (type))
 296         {
 297           /* Print the unmangled name if desired.  */
 298           /* Print vtable entry - we only get here if NOT using
 299              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_PTR.) */
 300           int offset = (embedded_offset +
 301                         TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
 302           struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
 303           CORE_ADDR addr
 304             = extract_typed_address (valaddr + offset, field_type);
 305
 306           print_function_pointer_address (addr, stream);
 307         }
 308       else
 309         cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream, format,
 310                                recurse, pretty, NULL, 0);
 311       break;
 312
 313     case TYPE_CODE_ENUM:
 314       if (format)
 315         {
 316           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 317           break;
 318         }
 319       len = TYPE_NFIELDS (type);
 320       val = unpack_long (type, valaddr + embedded_offset);
 321       for (i = 0; i < len; i++)
 322         {
 323           QUIT;
 324           if (val == TYPE_FIELD_BITPOS (type, i))
 325             {
 326               break;
 327             }
 328         }
 329       if (i < len)
 330         {
 331           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 332         }
 333       else
 334         {
 335           print_longest (stream, 'd', 0, val);
 336         }
 337       break;
 338
 339     case TYPE_CODE_FLAGS:
 340       if (format)
 341           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 342       else
 343         val_print_type_code_flags (type, valaddr + embedded_offset, stream);
 344       break;
 345
 346     case TYPE_CODE_FUNC:
 347     case TYPE_CODE_METHOD:
 348       if (format)
 349         {
 350           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 351           break;
 352         }
 353       /* FIXME, we should consider, at least for ANSI C language, eliminating
 354          the distinction made between FUNCs and POINTERs to FUNCs.  */
 355       fprintf_filtered (stream, "{");
 356       type_print (type, "", stream, -1);
 357       fprintf_filtered (stream, "} ");
 358       /* Try to print what function it points to, and its address.  */
 359       print_address_demangle (address, stream, demangle);
 360       break;
 361
 362     case TYPE_CODE_BOOL:
 363       format = format ? format : output_format;
 364       if (format)
 365         print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 366       else
 367         {
 368           val = unpack_long (type, valaddr + embedded_offset);
 369           if (val == 0)
 370             fputs_filtered ("false", stream);
 371           else if (val == 1)
 372             fputs_filtered ("true", stream);
 373           else
 374             print_longest (stream, 'd', 0, val);
 375         }
 376       break;
 377
 378     case TYPE_CODE_RANGE:
 379       /* FIXME: create_range_type does not set the unsigned bit in a
 380          range type (I think it probably should copy it from the target
 381          type), so we won't print values which are too large to
 382          fit in a signed integer correctly.  */
 383       /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
 384          print with the target type, though, because the size of our type
 385          and the target type might differ).  */
 386       /* FALLTHROUGH */
 387
 388     case TYPE_CODE_INT:
 389       format = format ? format : output_format;
 390       if (format)
 391         {
 392           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 393         }
 394       else
 395         {
 396           val_print_type_code_int (type, valaddr + embedded_offset, stream);
 397           /* C and C++ has no single byte int type, char is used instead.
 398              Since we don't know whether the value is really intended to
 399              be used as an integer or a character, print the character
 400              equivalent as well. */
 401           if (TYPE_LENGTH (type) == 1)
 402             {
 403               fputs_filtered (" ", stream);
 404               LA_PRINT_CHAR ((unsigned char) unpack_long (type, valaddr + embedded_offset),
 405                              stream);
 406             }
 407         }
 408       break;
 409
 410     case TYPE_CODE_CHAR:
 411       format = format ? format : output_format;
 412       if (format)
 413         {
 414           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 415         }
 416       else
 417         {
 418           val = unpack_long (type, valaddr + embedded_offset);
 419           if (TYPE_UNSIGNED (type))
 420             fprintf_filtered (stream, "%u", (unsigned int) val);
 421           else
 422             fprintf_filtered (stream, "%d", (int) val);
 423           fputs_filtered (" ", stream);
 424           LA_PRINT_CHAR ((unsigned char) val, stream);
 425         }
 426       break;
 427
 428     case TYPE_CODE_FLT:
 429       if (format)
 430         {
 431           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 432         }
 433       else
 434         {
 435           print_floating (valaddr + embedded_offset, type, stream);
 436         }
 437       break;
 438
 439     case TYPE_CODE_VOID:
 440       fprintf_filtered (stream, "void");
 441       break;
 442
 443     case TYPE_CODE_ERROR:
 444       fprintf_filtered (stream, _("<error type>"));
 445       break;
 446
 447     case TYPE_CODE_UNDEF:
 448       /* This happens (without TYPE_FLAG_STUB set) on systems which don't use
 449          dbx xrefs (NO_DBX_XREFS in gcc) if a file has a "struct foo *bar"
 450          and no complete type for struct foo in that file.  */
 451       fprintf_filtered (stream, _("<incomplete type>"));
 452       break;
 453
 454     case TYPE_CODE_COMPLEX:
 455       if (format)
 456         print_scalar_formatted (valaddr + embedded_offset,
 457                                 TYPE_TARGET_TYPE (type),
 458                                 format, 0, stream);
 459       else
 460         print_floating (valaddr + embedded_offset, TYPE_TARGET_TYPE (type),
 461                         stream);
 462       fprintf_filtered (stream, " + ");
 463       if (format)
 464         print_scalar_formatted (valaddr + embedded_offset
 465                                 + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 466                                 TYPE_TARGET_TYPE (type),
 467                                 format, 0, stream);
 468       else
 469         print_floating (valaddr + embedded_offset
 470                         + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 471                         TYPE_TARGET_TYPE (type),
 472                         stream);
 473       fprintf_filtered (stream, " * I");
 474       break;
 475
 476     default:
 477       error (_("Invalid C/C++ type code %d in symbol table."), TYPE_CODE (type));
 478     }
 479   gdb_flush (stream);
 480   return (0);
 481 }
 482 \f
 483 int
 484 c_value_print (struct value *val, struct ui_file *stream, int format,
 485                enum val_prettyprint pretty)
 486 {
 487   struct type *type, *real_type;
 488   int full, top, using_enc;
 489
 490   /* If it is a pointer, indicate what it points to.
 491
 492      Print type also if it is a reference.
 493
 494      C++: if it is a member pointer, we will take care
 495      of that when we print it.  */
 496
 497   type = check_typedef (value_type (val));
 498
 499   if (TYPE_CODE (type) == TYPE_CODE_PTR
 500       || TYPE_CODE (type) == TYPE_CODE_REF)
 501     {
 502       /* Hack:  remove (char *) for char strings.  Their
 503          type is indicated by the quoted string anyway. */
 504       if (TYPE_CODE (type) == TYPE_CODE_PTR
 505           && TYPE_NAME (type) == NULL
 506           && TYPE_NAME (TYPE_TARGET_TYPE (type)) != NULL
 507           && strcmp (TYPE_NAME (TYPE_TARGET_TYPE (type)), "char") == 0)
 508         {
 509           /* Print nothing */
 510         }
 511       else if (objectprint && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 512         {
 513
 514           if (TYPE_CODE(type) == TYPE_CODE_REF)
 515             {
 516               /* Copy value, change to pointer, so we don't get an
 517                * error about a non-pointer type in value_rtti_target_type
 518                */
 519               struct value *temparg;
 520               temparg=value_copy(val);
 521               deprecated_set_value_type (temparg, lookup_pointer_type (TYPE_TARGET_TYPE(type)));
 522               val=temparg;
 523             }
 524           /* Pointer to class, check real type of object */
 525           fprintf_filtered (stream, "(");
 526           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 527           if (real_type)
 528             {
 529               /* RTTI entry found */
 530               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 531                 {
 532                   /* create a pointer type pointing to the real type */
 533                   type = lookup_pointer_type (real_type);
 534                 }
 535               else
 536                 {
 537                   /* create a reference type referencing the real type */
 538                   type = lookup_reference_type (real_type);
 539                 }
 540               /* JYG: Need to adjust pointer value. */
 541               /* NOTE: cagney/2005-01-02: THIS IS BOGUS.  */
 542               value_contents_writeable (val)[0] -= top;
 543
 544               /* Note: When we look up RTTI entries, we don't get any
 545                  information on const or volatile attributes */
 546             }
 547           type_print (type, "", stream, -1);
 548           fprintf_filtered (stream, ") ");
 549         }
 550       else
 551         {
 552           /* normal case */
 553           fprintf_filtered (stream, "(");
 554           type_print (value_type (val), "", stream, -1);
 555           fprintf_filtered (stream, ") ");
 556         }
 557     }
 558
 559   if (objectprint && (TYPE_CODE (type) == TYPE_CODE_CLASS))
 560     {
 561       /* Attempt to determine real type of object */
 562       real_type = value_rtti_type (val, &full, &top, &using_enc);
 563       if (real_type)
 564         {
 565           /* We have RTTI information, so use it */
 566           val = value_full_object (val, real_type, full, top, using_enc);
 567           fprintf_filtered (stream, "(%s%s) ",
 568                             TYPE_NAME (real_type),
 569                             full ? "" : _(" [incomplete object]"));
 570           /* Print out object: enclosing type is same as real_type if full */
 571           return val_print (value_enclosing_type (val),
 572                             value_contents_all (val), 0,
 573                             VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 574           /* Note: When we look up RTTI entries, we don't get any information on
 575              const or volatile attributes */
 576         }
 577       else if (type != check_typedef (value_enclosing_type (val)))
 578         {
 579           /* No RTTI information, so let's do our best */
 580           fprintf_filtered (stream, "(%s ?) ",
 581                             TYPE_NAME (value_enclosing_type (val)));
 582           return val_print (value_enclosing_type (val),
 583                             value_contents_all (val), 0,
 584                             VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 585         }
 586       /* Otherwise, we end up at the return outside this "if" */
 587     }
 588
 589   return val_print (type, value_contents_all (val),
 590                     value_embedded_offset (val),
 591                     VALUE_ADDRESS (val) + value_offset (val),
 592                     stream, format, 1, 0, pretty);
 593 }