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,
   4    1997, 1998, 1999, 2000, 2001, 2003, 2005, 2006
   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_PTR:
 146       if (format && format != 's')
 147         {
 148           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 149           break;
 150         }
 151       if (vtblprint && cp_is_vtbl_ptr_type (type))
 152         {
 153           /* Print the unmangled name if desired.  */
 154           /* Print vtable entry - we only get here if we ARE using
 155              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_STRUCT.) */
 156           CORE_ADDR addr
 157             = extract_typed_address (valaddr + embedded_offset, type);
 158           print_function_pointer_address (addr, stream);
 159           break;
 160         }
 161       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 162       if (TYPE_CODE (elttype) == TYPE_CODE_METHOD)
 163         {
 164           cp_print_class_method (valaddr + embedded_offset, type, stream);
 165         }
 166       else if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
 167         {
 168           cp_print_class_member (valaddr + embedded_offset,
 169                                  TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (type)),
 170                                  stream, "&");
 171         }
 172       else
 173         {
 174           addr = unpack_pointer (type, valaddr + embedded_offset);
 175         print_unpacked_pointer:
 176
 177           if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
 178             {
 179               /* Try to print what function it points to.  */
 180               print_function_pointer_address (addr, stream);
 181               /* Return value is irrelevant except for string pointers.  */
 182               return (0);
 183             }
 184
 185           if (addressprint && format != 's')
 186             {
 187               deprecated_print_address_numeric (addr, 1, stream);
 188             }
 189
 190           /* For a pointer to char or unsigned char, also print the string
 191              pointed to, unless pointer is null.  */
 192           /* FIXME: need to handle wchar_t here... */
 193
 194           if (TYPE_LENGTH (elttype) == 1
 195               && TYPE_CODE (elttype) == TYPE_CODE_INT
 196               && (format == 0 || format == 's')
 197               && addr != 0)
 198             {
 199               i = val_print_string (addr, -1, TYPE_LENGTH (elttype), stream);
 200             }
 201           else if (cp_is_vtbl_member (type))
 202             {
 203               /* print vtbl's nicely */
 204               CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
 205
 206               struct minimal_symbol *msymbol =
 207               lookup_minimal_symbol_by_pc (vt_address);
 208               if ((msymbol != NULL) &&
 209                   (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
 210                 {
 211                   fputs_filtered (" <", stream);
 212                   fputs_filtered (SYMBOL_PRINT_NAME (msymbol), stream);
 213                   fputs_filtered (">", stream);
 214                 }
 215               if (vt_address && vtblprint)
 216                 {
 217                   struct value *vt_val;
 218                   struct symbol *wsym = (struct symbol *) NULL;
 219                   struct type *wtype;
 220                   struct block *block = (struct block *) NULL;
 221                   int is_this_fld;
 222
 223                   if (msymbol != NULL)
 224                     wsym = lookup_symbol (DEPRECATED_SYMBOL_NAME (msymbol), block,
 225                                           VAR_DOMAIN, &is_this_fld, NULL);
 226
 227                   if (wsym)
 228                     {
 229                       wtype = SYMBOL_TYPE (wsym);
 230                     }
 231                   else
 232                     {
 233                       wtype = TYPE_TARGET_TYPE (type);
 234                     }
 235                   vt_val = value_at (wtype, vt_address);
 236                   common_val_print (vt_val, stream, format,
 237                                     deref_ref, recurse + 1, pretty);
 238                   if (pretty)
 239                     {
 240                       fprintf_filtered (stream, "\n");
 241                       print_spaces_filtered (2 + 2 * recurse, stream);
 242                     }
 243                 }
 244             }
 245
 246           /* Return number of characters printed, including the terminating
 247              '\0' if we reached the end.  val_print_string takes care including
 248              the terminating '\0' if necessary.  */
 249           return i;
 250         }
 251       break;
 252
 253     case TYPE_CODE_MEMBER:
 254       error (_("not implemented: member type in c_val_print"));
 255       break;
 256
 257     case TYPE_CODE_REF:
 258       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 259       if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
 260         {
 261           cp_print_class_member (valaddr + embedded_offset,
 262                                  TYPE_DOMAIN_TYPE (elttype),
 263                                  stream, "");
 264           break;
 265         }
 266       if (addressprint)
 267         {
 268           CORE_ADDR addr
 269             = extract_typed_address (valaddr + embedded_offset, type);
 270           fprintf_filtered (stream, "@");
 271           deprecated_print_address_numeric (addr, 1, stream);
 272           if (deref_ref)
 273             fputs_filtered (": ", stream);
 274         }
 275       /* De-reference the reference.  */
 276       if (deref_ref)
 277         {
 278           if (TYPE_CODE (elttype) != TYPE_CODE_UNDEF)
 279             {
 280               struct value *deref_val =
 281               value_at
 282               (TYPE_TARGET_TYPE (type),
 283                unpack_pointer (lookup_pointer_type (builtin_type_void),
 284                                valaddr + embedded_offset));
 285               common_val_print (deref_val, stream, format, deref_ref,
 286                                 recurse, pretty);
 287             }
 288           else
 289             fputs_filtered ("???", stream);
 290         }
 291       break;
 292
 293     case TYPE_CODE_UNION:
 294       if (recurse && !unionprint)
 295         {
 296           fprintf_filtered (stream, "{...}");
 297           break;
 298         }
 299       /* Fall through.  */
 300     case TYPE_CODE_STRUCT:
 301       /*FIXME: Abstract this away */
 302       if (vtblprint && cp_is_vtbl_ptr_type (type))
 303         {
 304           /* Print the unmangled name if desired.  */
 305           /* Print vtable entry - we only get here if NOT using
 306              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_PTR.) */
 307           int offset = (embedded_offset +
 308                         TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
 309           struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
 310           CORE_ADDR addr
 311             = extract_typed_address (valaddr + offset, field_type);
 312
 313           print_function_pointer_address (addr, stream);
 314         }
 315       else
 316         cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream, format,
 317                                recurse, pretty, NULL, 0);
 318       break;
 319
 320     case TYPE_CODE_ENUM:
 321       if (format)
 322         {
 323           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 324           break;
 325         }
 326       len = TYPE_NFIELDS (type);
 327       val = unpack_long (type, valaddr + embedded_offset);
 328       for (i = 0; i < len; i++)
 329         {
 330           QUIT;
 331           if (val == TYPE_FIELD_BITPOS (type, i))
 332             {
 333               break;
 334             }
 335         }
 336       if (i < len)
 337         {
 338           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 339         }
 340       else
 341         {
 342           print_longest (stream, 'd', 0, val);
 343         }
 344       break;
 345
 346     case TYPE_CODE_FLAGS:
 347       if (format)
 348           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 349       else
 350         val_print_type_code_flags (type, valaddr + embedded_offset, stream);
 351       break;
 352
 353     case TYPE_CODE_FUNC:
 354       if (format)
 355         {
 356           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 357           break;
 358         }
 359       /* FIXME, we should consider, at least for ANSI C language, eliminating
 360          the distinction made between FUNCs and POINTERs to FUNCs.  */
 361       fprintf_filtered (stream, "{");
 362       type_print (type, "", stream, -1);
 363       fprintf_filtered (stream, "} ");
 364       /* Try to print what function it points to, and its address.  */
 365       print_address_demangle (address, stream, demangle);
 366       break;
 367
 368     case TYPE_CODE_BOOL:
 369       format = format ? format : output_format;
 370       if (format)
 371         print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 372       else
 373         {
 374           val = unpack_long (type, valaddr + embedded_offset);
 375           if (val == 0)
 376             fputs_filtered ("false", stream);
 377           else if (val == 1)
 378             fputs_filtered ("true", stream);
 379           else
 380             print_longest (stream, 'd', 0, val);
 381         }
 382       break;
 383
 384     case TYPE_CODE_RANGE:
 385       /* FIXME: create_range_type does not set the unsigned bit in a
 386          range type (I think it probably should copy it from the target
 387          type), so we won't print values which are too large to
 388          fit in a signed integer correctly.  */
 389       /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
 390          print with the target type, though, because the size of our type
 391          and the target type might differ).  */
 392       /* FALLTHROUGH */
 393
 394     case TYPE_CODE_INT:
 395       format = format ? format : output_format;
 396       if (format)
 397         {
 398           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 399         }
 400       else
 401         {
 402           val_print_type_code_int (type, valaddr + embedded_offset, stream);
 403           /* C and C++ has no single byte int type, char is used instead.
 404              Since we don't know whether the value is really intended to
 405              be used as an integer or a character, print the character
 406              equivalent as well. */
 407           if (TYPE_LENGTH (type) == 1)
 408             {
 409               fputs_filtered (" ", stream);
 410               LA_PRINT_CHAR ((unsigned char) unpack_long (type, valaddr + embedded_offset),
 411                              stream);
 412             }
 413         }
 414       break;
 415
 416     case TYPE_CODE_CHAR:
 417       format = format ? format : output_format;
 418       if (format)
 419         {
 420           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 421         }
 422       else
 423         {
 424           val = unpack_long (type, valaddr + embedded_offset);
 425           if (TYPE_UNSIGNED (type))
 426             fprintf_filtered (stream, "%u", (unsigned int) val);
 427           else
 428             fprintf_filtered (stream, "%d", (int) val);
 429           fputs_filtered (" ", stream);
 430           LA_PRINT_CHAR ((unsigned char) val, stream);
 431         }
 432       break;
 433
 434     case TYPE_CODE_FLT:
 435       if (format)
 436         {
 437           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 438         }
 439       else
 440         {
 441           print_floating (valaddr + embedded_offset, type, stream);
 442         }
 443       break;
 444
 445     case TYPE_CODE_METHOD:
 446       {
 447         struct value *v = value_at (type, address);
 448         cp_print_class_method (value_contents (value_addr (v)),
 449                                lookup_pointer_type (type), stream);
 450         break;
 451       }
 452
 453     case TYPE_CODE_VOID:
 454       fprintf_filtered (stream, "void");
 455       break;
 456
 457     case TYPE_CODE_ERROR:
 458       fprintf_filtered (stream, _("<error type>"));
 459       break;
 460
 461     case TYPE_CODE_UNDEF:
 462       /* This happens (without TYPE_FLAG_STUB set) on systems which don't use
 463          dbx xrefs (NO_DBX_XREFS in gcc) if a file has a "struct foo *bar"
 464          and no complete type for struct foo in that file.  */
 465       fprintf_filtered (stream, _("<incomplete type>"));
 466       break;
 467
 468     case TYPE_CODE_COMPLEX:
 469       if (format)
 470         print_scalar_formatted (valaddr + embedded_offset,
 471                                 TYPE_TARGET_TYPE (type),
 472                                 format, 0, stream);
 473       else
 474         print_floating (valaddr + embedded_offset, TYPE_TARGET_TYPE (type),
 475                         stream);
 476       fprintf_filtered (stream, " + ");
 477       if (format)
 478         print_scalar_formatted (valaddr + embedded_offset
 479                                 + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 480                                 TYPE_TARGET_TYPE (type),
 481                                 format, 0, stream);
 482       else
 483         print_floating (valaddr + embedded_offset
 484                         + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 485                         TYPE_TARGET_TYPE (type),
 486                         stream);
 487       fprintf_filtered (stream, " * I");
 488       break;
 489
 490     default:
 491       error (_("Invalid C/C++ type code %d in symbol table."), TYPE_CODE (type));
 492     }
 493   gdb_flush (stream);
 494   return (0);
 495 }
 496 \f
 497 int
 498 c_value_print (struct value *val, struct ui_file *stream, int format,
 499                enum val_prettyprint pretty)
 500 {
 501   struct type *type, *real_type;
 502   int full, top, using_enc;
 503
 504   /* If it is a pointer, indicate what it points to.
 505
 506      Print type also if it is a reference.
 507
 508      C++: if it is a member pointer, we will take care
 509      of that when we print it.  */
 510
 511   type = check_typedef (value_type (val));
 512
 513   if (TYPE_CODE (type) == TYPE_CODE_PTR
 514       || TYPE_CODE (type) == TYPE_CODE_REF)
 515     {
 516       /* Hack:  remove (char *) for char strings.  Their
 517          type is indicated by the quoted string anyway. */
 518       if (TYPE_CODE (type) == TYPE_CODE_PTR
 519           && TYPE_NAME (type) == NULL
 520           && TYPE_NAME (TYPE_TARGET_TYPE (type)) != NULL
 521           && strcmp (TYPE_NAME (TYPE_TARGET_TYPE (type)), "char") == 0)
 522         {
 523           /* Print nothing */
 524         }
 525       else if (objectprint && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 526         {
 527
 528           if (TYPE_CODE(type) == TYPE_CODE_REF)
 529             {
 530               /* Copy value, change to pointer, so we don't get an
 531                * error about a non-pointer type in value_rtti_target_type
 532                */
 533               struct value *temparg;
 534               temparg=value_copy(val);
 535               deprecated_set_value_type (temparg, lookup_pointer_type (TYPE_TARGET_TYPE(type)));
 536               val=temparg;
 537             }
 538           /* Pointer to class, check real type of object */
 539           fprintf_filtered (stream, "(");
 540           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 541           if (real_type)
 542             {
 543               /* RTTI entry found */
 544               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 545                 {
 546                   /* create a pointer type pointing to the real type */
 547                   type = lookup_pointer_type (real_type);
 548                 }
 549               else
 550                 {
 551                   /* create a reference type referencing the real type */
 552                   type = lookup_reference_type (real_type);
 553                 }
 554               /* JYG: Need to adjust pointer value. */
 555               /* NOTE: cagney/2005-01-02: THIS IS BOGUS.  */
 556               value_contents_writeable (val)[0] -= top;
 557
 558               /* Note: When we look up RTTI entries, we don't get any
 559                  information on const or volatile attributes */
 560             }
 561           type_print (type, "", stream, -1);
 562           fprintf_filtered (stream, ") ");
 563         }
 564       else
 565         {
 566           /* normal case */
 567           fprintf_filtered (stream, "(");
 568           type_print (value_type (val), "", stream, -1);
 569           fprintf_filtered (stream, ") ");
 570         }
 571     }
 572
 573   if (objectprint && (TYPE_CODE (type) == TYPE_CODE_CLASS))
 574     {
 575       /* Attempt to determine real type of object */
 576       real_type = value_rtti_type (val, &full, &top, &using_enc);
 577       if (real_type)
 578         {
 579           /* We have RTTI information, so use it */
 580           val = value_full_object (val, real_type, full, top, using_enc);
 581           fprintf_filtered (stream, "(%s%s) ",
 582                             TYPE_NAME (real_type),
 583                             full ? "" : _(" [incomplete object]"));
 584           /* Print out object: enclosing type is same as real_type if full */
 585           return val_print (value_enclosing_type (val),
 586                             value_contents_all (val), 0,
 587                             VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 588           /* Note: When we look up RTTI entries, we don't get any information on
 589              const or volatile attributes */
 590         }
 591       else if (type != check_typedef (value_enclosing_type (val)))
 592         {
 593           /* No RTTI information, so let's do our best */
 594           fprintf_filtered (stream, "(%s ?) ",
 595                             TYPE_NAME (value_enclosing_type (val)));
 596           return val_print (value_enclosing_type (val),
 597                             value_contents_all (val), 0,
 598                             VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 599         }
 600       /* Otherwise, we end up at the return outside this "if" */
 601     }
 602
 603   return val_print (type, value_contents_all (val),
 604                     value_embedded_offset (val),
 605                     VALUE_ADDRESS (val) + value_offset (val),
 606                     stream, format, 1, 0, pretty);
 607 }