gdb/c-valprint.c

   1 /* Support for printing C values for GDB, the GNU debugger.
   2
   3    Copyright 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996,
   4    1997, 1998, 1999, 2000, 2001, 2003 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "gdb_string.h"
  25 #include "symtab.h"
  26 #include "gdbtypes.h"
  27 #include "expression.h"
  28 #include "value.h"
  29 #include "valprint.h"
  30 #include "language.h"
  31 #include "c-lang.h"
  32 #include "cp-abi.h"
  33 #include "target.h"
  34 \f
  35
  36 /* Print function pointer with inferior address ADDRESS onto stdio
  37    stream STREAM.  */
  38
  39 static void
  40 print_function_pointer_address (CORE_ADDR address, struct ui_file *stream)
  41 {
  42   CORE_ADDR func_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
  43                                                             address,
  44                                                             &current_target);
  45
  46   /* If the function pointer is represented by a description, print the
  47      address of the description.  */
  48   if (addressprint && func_addr != address)
  49     {
  50       fputs_filtered ("@", stream);
  51       print_address_numeric (address, 1, stream);
  52       fputs_filtered (": ", stream);
  53     }
  54   print_address_demangle (func_addr, stream, demangle);
  55 }
  56
  57
  58 /* Print data of type TYPE located at VALADDR (within GDB), which came from
  59    the inferior at address ADDRESS, onto stdio stream STREAM according to
  60    FORMAT (a letter or 0 for natural format).  The data at VALADDR is in
  61    target byte order.
  62
  63    If the data are a string pointer, returns the number of string characters
  64    printed.
  65
  66    If DEREF_REF is nonzero, then dereference references, otherwise just print
  67    them like pointers.
  68
  69    The PRETTY parameter controls prettyprinting.  */
  70
  71 int
  72 c_val_print (struct type *type, const bfd_byte *valaddr, int embedded_offset,
  73              CORE_ADDR address, struct ui_file *stream, int format,
  74              int deref_ref, int recurse, enum val_prettyprint pretty)
  75 {
  76   unsigned int i = 0;   /* Number of characters printed */
  77   unsigned len;
  78   struct type *elttype;
  79   unsigned eltlen;
  80   LONGEST val;
  81   CORE_ADDR addr;
  82
  83   CHECK_TYPEDEF (type);
  84   switch (TYPE_CODE (type))
  85     {
  86     case TYPE_CODE_ARRAY:
  87       elttype = check_typedef (TYPE_TARGET_TYPE (type));
  88       if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (TYPE_TARGET_TYPE (type)) > 0)
  89         {
  90           eltlen = TYPE_LENGTH (elttype);
  91           len = TYPE_LENGTH (type) / eltlen;
  92           if (prettyprint_arrays)
  93             {
  94               print_spaces_filtered (2 + 2 * recurse, stream);
  95             }
  96           /* For an array of chars, print with string syntax.  */
  97           if (eltlen == 1 &&
  98               ((TYPE_CODE (elttype) == TYPE_CODE_INT)
  99                || ((current_language->la_language == language_m2)
 100                    && (TYPE_CODE (elttype) == TYPE_CODE_CHAR)))
 101               && (format == 0 || format == 's'))
 102             {
 103               /* If requested, look for the first null char and only print
 104                  elements up to it.  */
 105               if (stop_print_at_null)
 106                 {
 107                   unsigned int temp_len;
 108
 109                   /* Look for a NULL char. */
 110                   for (temp_len = 0;
 111                        (valaddr + embedded_offset)[temp_len]
 112                        && temp_len < len && temp_len < print_max;
 113                        temp_len++);
 114                   len = temp_len;
 115                 }
 116
 117               LA_PRINT_STRING (stream, valaddr + embedded_offset, len, eltlen, 0);
 118               i = len;
 119             }
 120           else
 121             {
 122               fprintf_filtered (stream, "{");
 123               /* If this is a virtual function table, print the 0th
 124                  entry specially, and the rest of the members normally.  */
 125               if (cp_is_vtbl_ptr_type (elttype))
 126                 {
 127                   i = 1;
 128                   fprintf_filtered (stream, _("%d vtable entries"), len - 1);
 129                 }
 130               else
 131                 {
 132                   i = 0;
 133                 }
 134               val_print_array_elements (type, valaddr + embedded_offset, address, stream,
 135                                      format, deref_ref, recurse, pretty, i);
 136               fprintf_filtered (stream, "}");
 137             }
 138           break;
 139         }
 140       /* Array of unspecified length: treat like pointer to first elt.  */
 141       addr = address;
 142       goto print_unpacked_pointer;
 143
 144     case TYPE_CODE_PTR:
 145       if (format && format != 's')
 146         {
 147           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 148           break;
 149         }
 150       if (vtblprint && cp_is_vtbl_ptr_type (type))
 151         {
 152           /* Print the unmangled name if desired.  */
 153           /* Print vtable entry - we only get here if we ARE using
 154              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_STRUCT.) */
 155           CORE_ADDR addr
 156             = extract_typed_address (valaddr + embedded_offset, type);
 157           print_function_pointer_address (addr, stream);
 158           break;
 159         }
 160       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 161       if (TYPE_CODE (elttype) == TYPE_CODE_METHOD)
 162         {
 163           cp_print_class_method (valaddr + embedded_offset, type, stream);
 164         }
 165       else if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
 166         {
 167           cp_print_class_member (valaddr + embedded_offset,
 168                                  TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (type)),
 169                                  stream, "&");
 170         }
 171       else
 172         {
 173           addr = unpack_pointer (type, valaddr + embedded_offset);
 174         print_unpacked_pointer:
 175
 176           if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
 177             {
 178               /* Try to print what function it points to.  */
 179               print_function_pointer_address (addr, stream);
 180               /* Return value is irrelevant except for string pointers.  */
 181               return (0);
 182             }
 183
 184           if (addressprint && format != 's')
 185             {
 186               print_address_numeric (addr, 1, stream);
 187             }
 188
 189           /* For a pointer to char or unsigned char, also print the string
 190              pointed to, unless pointer is null.  */
 191           /* FIXME: need to handle wchar_t here... */
 192
 193           if (TYPE_LENGTH (elttype) == 1
 194               && TYPE_CODE (elttype) == TYPE_CODE_INT
 195               && (format == 0 || format == 's')
 196               && addr != 0)
 197             {
 198               i = val_print_string (addr, -1, TYPE_LENGTH (elttype), stream);
 199             }
 200           else if (cp_is_vtbl_member (type))
 201             {
 202               /* print vtbl's nicely */
 203               CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
 204
 205               struct minimal_symbol *msymbol =
 206               lookup_minimal_symbol_by_pc (vt_address);
 207               if ((msymbol != NULL) &&
 208                   (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
 209                 {
 210                   fputs_filtered (" <", stream);
 211                   fputs_filtered (SYMBOL_PRINT_NAME (msymbol), stream);
 212                   fputs_filtered (">", stream);
 213                 }
 214               if (vt_address && vtblprint)
 215                 {
 216                   struct value *vt_val;
 217                   struct symbol *wsym = (struct symbol *) NULL;
 218                   struct type *wtype;
 219                   struct block *block = (struct block *) NULL;
 220                   int is_this_fld;
 221
 222                   if (msymbol != NULL)
 223                     wsym = lookup_symbol (DEPRECATED_SYMBOL_NAME (msymbol), block,
 224                                           VAR_DOMAIN, &is_this_fld, NULL);
 225
 226                   if (wsym)
 227                     {
 228                       wtype = SYMBOL_TYPE (wsym);
 229                     }
 230                   else
 231                     {
 232                       wtype = TYPE_TARGET_TYPE (type);
 233                     }
 234                   vt_val = value_at (wtype, vt_address);
 235                   val_print (value_type (vt_val), VALUE_CONTENTS (vt_val), 0,
 236                              VALUE_ADDRESS (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           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               val_print (value_type (deref_val),
 286                          VALUE_CONTENTS (deref_val),
 287                          0,
 288                          VALUE_ADDRESS (deref_val),
 289                          stream,
 290                          format,
 291                          deref_ref,
 292                          recurse,
 293                          pretty);
 294             }
 295           else
 296             fputs_filtered ("???", stream);
 297         }
 298       break;
 299
 300     case TYPE_CODE_UNION:
 301       if (recurse && !unionprint)
 302         {
 303           fprintf_filtered (stream, "{...}");
 304           break;
 305         }
 306       /* Fall through.  */
 307     case TYPE_CODE_STRUCT:
 308       /*FIXME: Abstract this away */
 309       if (vtblprint && cp_is_vtbl_ptr_type (type))
 310         {
 311           /* Print the unmangled name if desired.  */
 312           /* Print vtable entry - we only get here if NOT using
 313              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_PTR.) */
 314           int offset = (embedded_offset +
 315                         TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
 316           struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
 317           CORE_ADDR addr
 318             = extract_typed_address (valaddr + offset, field_type);
 319
 320           print_function_pointer_address (addr, stream);
 321         }
 322       else
 323         cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream, format,
 324                                recurse, pretty, NULL, 0);
 325       break;
 326
 327     case TYPE_CODE_ENUM:
 328       if (format)
 329         {
 330           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 331           break;
 332         }
 333       len = TYPE_NFIELDS (type);
 334       val = unpack_long (type, valaddr + embedded_offset);
 335       for (i = 0; i < len; i++)
 336         {
 337           QUIT;
 338           if (val == TYPE_FIELD_BITPOS (type, i))
 339             {
 340               break;
 341             }
 342         }
 343       if (i < len)
 344         {
 345           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 346         }
 347       else
 348         {
 349           print_longest (stream, 'd', 0, val);
 350         }
 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 = value_type (val);
 502   struct type *real_type;
 503   int full, top, using_enc;
 504
 505   /* If it is a pointer, indicate what it points to.
 506
 507      Print type also if it is a reference.
 508
 509      C++: if it is a member pointer, we will take care
 510      of that when we print it.  */
 511   if (TYPE_CODE (type) == TYPE_CODE_PTR ||
 512       TYPE_CODE (type) == TYPE_CODE_REF)
 513     {
 514       /* Hack:  remove (char *) for char strings.  Their
 515          type is indicated by the quoted string anyway. */
 516       if (TYPE_CODE (type) == TYPE_CODE_PTR &&
 517           TYPE_NAME (type) == NULL &&
 518           TYPE_NAME (TYPE_TARGET_TYPE (type)) != NULL &&
 519           strcmp (TYPE_NAME (TYPE_TARGET_TYPE (type)), "char") == 0)
 520         {
 521           /* Print nothing */
 522         }
 523       else if (objectprint && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 524         {
 525
 526           if (TYPE_CODE(type) == TYPE_CODE_REF)
 527             {
 528               /* Copy value, change to pointer, so we don't get an
 529                * error about a non-pointer type in value_rtti_target_type
 530                */
 531               struct value *temparg;
 532               temparg=value_copy(val);
 533               temparg->type = lookup_pointer_type (TYPE_TARGET_TYPE(type));
 534               val=temparg;
 535             }
 536           /* Pointer to class, check real type of object */
 537           fprintf_filtered (stream, "(");
 538           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 539           if (real_type)
 540             {
 541               /* RTTI entry found */
 542               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 543                 {
 544                   /* create a pointer type pointing to the real type */
 545                   type = lookup_pointer_type (real_type);
 546                 }
 547               else
 548                 {
 549                   /* create a reference type referencing the real type */
 550                   type = lookup_reference_type (real_type);
 551                 }
 552               /* JYG: Need to adjust pointer value. */
 553               val->aligner.contents[0] -= top;
 554
 555               /* Note: When we look up RTTI entries, we don't get any
 556                  information on const or volatile attributes */
 557             }
 558           type_print (type, "", stream, -1);
 559           fprintf_filtered (stream, ") ");
 560         }
 561       else
 562         {
 563           /* normal case */
 564           fprintf_filtered (stream, "(");
 565           type_print (type, "", stream, -1);
 566           fprintf_filtered (stream, ") ");
 567         }
 568     }
 569   if (objectprint && (TYPE_CODE (value_type (val)) == TYPE_CODE_CLASS))
 570     {
 571       /* Attempt to determine real type of object */
 572       real_type = value_rtti_type (val, &full, &top, &using_enc);
 573       if (real_type)
 574         {
 575           /* We have RTTI information, so use it */
 576           val = value_full_object (val, real_type, full, top, using_enc);
 577           fprintf_filtered (stream, "(%s%s) ",
 578                             TYPE_NAME (real_type),
 579                             full ? "" : _(" [incomplete object]"));
 580           /* Print out object: enclosing type is same as real_type if full */
 581           return val_print (VALUE_ENCLOSING_TYPE (val), VALUE_CONTENTS_ALL (val), 0,
 582                          VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 583           /* Note: When we look up RTTI entries, we don't get any information on
 584              const or volatile attributes */
 585         }
 586       else if (type != VALUE_ENCLOSING_TYPE (val))
 587         {
 588           /* No RTTI information, so let's do our best */
 589           fprintf_filtered (stream, "(%s ?) ",
 590                             TYPE_NAME (VALUE_ENCLOSING_TYPE (val)));
 591           return val_print (VALUE_ENCLOSING_TYPE (val), VALUE_CONTENTS_ALL (val), 0,
 592                          VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 593         }
 594       /* Otherwise, we end up at the return outside this "if" */
 595     }
 596
 597   return val_print (type, VALUE_CONTENTS_ALL (val),
 598                     VALUE_EMBEDDED_OFFSET (val),
 599                     VALUE_ADDRESS (val) + value_offset (val),
 600                     stream, format, 1, 0, pretty);
 601 }