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,
 193                              TYPE_DOMAIN_TYPE (type),
 194                              stream, "&");
 195       break;
 196
 197     case TYPE_CODE_METHODPTR:
 198       cplus_print_method_ptr (valaddr + embedded_offset, type, stream);
 199       break;
 200
 201     case TYPE_CODE_PTR:
 202       if (format && format != 's')
 203         {
 204           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 205           break;
 206         }
 207       if (vtblprint && cp_is_vtbl_ptr_type (type))
 208         {
 209           /* Print the unmangled name if desired.  */
 210           /* Print vtable entry - we only get here if we ARE using
 211              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_STRUCT.) */
 212           CORE_ADDR addr
 213             = extract_typed_address (valaddr + embedded_offset, type);
 214           print_function_pointer_address (addr, stream);
 215           break;
 216         }
 217       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 218         {
 219           addr = unpack_pointer (type, valaddr + embedded_offset);
 220         print_unpacked_pointer:
 221
 222           if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
 223             {
 224               /* Try to print what function it points to.  */
 225               print_function_pointer_address (addr, stream);
 226               /* Return value is irrelevant except for string pointers.  */
 227               return (0);
 228             }
 229
 230           if (addressprint)
 231             fputs_filtered (paddress (addr), stream);
 232
 233           /* For a pointer to a textual type, also print the string
 234              pointed to, unless pointer is null.  */
 235           /* FIXME: need to handle wchar_t here... */
 236
 237           if (textual_element_type (elttype, format) && addr != 0)
 238             {
 239               i = val_print_string (addr, -1, TYPE_LENGTH (elttype), stream);
 240             }
 241           else if (cp_is_vtbl_member (type))
 242             {
 243               /* print vtbl's nicely */
 244               CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
 245
 246               struct minimal_symbol *msymbol =
 247               lookup_minimal_symbol_by_pc (vt_address);
 248               if ((msymbol != NULL) &&
 249                   (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
 250                 {
 251                   fputs_filtered (" <", stream);
 252                   fputs_filtered (SYMBOL_PRINT_NAME (msymbol), stream);
 253                   fputs_filtered (">", stream);
 254                 }
 255               if (vt_address && vtblprint)
 256                 {
 257                   struct value *vt_val;
 258                   struct symbol *wsym = (struct symbol *) NULL;
 259                   struct type *wtype;
 260                   struct block *block = (struct block *) NULL;
 261                   int is_this_fld;
 262
 263                   if (msymbol != NULL)
 264                     wsym = lookup_symbol (SYMBOL_LINKAGE_NAME (msymbol), block,
 265                                           VAR_DOMAIN, &is_this_fld);
 266
 267                   if (wsym)
 268                     {
 269                       wtype = SYMBOL_TYPE (wsym);
 270                     }
 271                   else
 272                     {
 273                       wtype = TYPE_TARGET_TYPE (type);
 274                     }
 275                   vt_val = value_at (wtype, vt_address);
 276                   common_val_print (vt_val, stream, format,
 277                                     deref_ref, recurse + 1, pretty,
 278                                     current_language);
 279                   if (pretty)
 280                     {
 281                       fprintf_filtered (stream, "\n");
 282                       print_spaces_filtered (2 + 2 * recurse, stream);
 283                     }
 284                 }
 285             }
 286
 287           /* Return number of characters printed, including the terminating
 288              '\0' if we reached the end.  val_print_string takes care including
 289              the terminating '\0' if necessary.  */
 290           return i;
 291         }
 292       break;
 293
 294     case TYPE_CODE_REF:
 295       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 296       if (addressprint)
 297         {
 298           CORE_ADDR addr
 299             = extract_typed_address (valaddr + embedded_offset, type);
 300           fprintf_filtered (stream, "@");
 301           fputs_filtered (paddress (addr), stream);
 302           if (deref_ref)
 303             fputs_filtered (": ", stream);
 304         }
 305       /* De-reference the reference.  */
 306       if (deref_ref)
 307         {
 308           if (TYPE_CODE (elttype) != TYPE_CODE_UNDEF)
 309             {
 310               struct value *deref_val =
 311               value_at
 312               (TYPE_TARGET_TYPE (type),
 313                unpack_pointer (type, valaddr + embedded_offset));
 314               common_val_print (deref_val, stream, format, deref_ref,
 315                                 recurse, pretty, current_language);
 316             }
 317           else
 318             fputs_filtered ("???", stream);
 319         }
 320       break;
 321
 322     case TYPE_CODE_UNION:
 323       if (recurse && !unionprint)
 324         {
 325           fprintf_filtered (stream, "{...}");
 326           break;
 327         }
 328       /* Fall through.  */
 329     case TYPE_CODE_STRUCT:
 330       /*FIXME: Abstract this away */
 331       if (vtblprint && cp_is_vtbl_ptr_type (type))
 332         {
 333           /* Print the unmangled name if desired.  */
 334           /* Print vtable entry - we only get here if NOT using
 335              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_PTR.) */
 336           int offset = (embedded_offset +
 337                         TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
 338           struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
 339           CORE_ADDR addr
 340             = extract_typed_address (valaddr + offset, field_type);
 341
 342           print_function_pointer_address (addr, stream);
 343         }
 344       else
 345         cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream, format,
 346                                recurse, pretty, NULL, 0);
 347       break;
 348
 349     case TYPE_CODE_ENUM:
 350       if (format)
 351         {
 352           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 353           break;
 354         }
 355       len = TYPE_NFIELDS (type);
 356       val = unpack_long (type, valaddr + embedded_offset);
 357       for (i = 0; i < len; i++)
 358         {
 359           QUIT;
 360           if (val == TYPE_FIELD_BITPOS (type, i))
 361             {
 362               break;
 363             }
 364         }
 365       if (i < len)
 366         {
 367           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 368         }
 369       else
 370         {
 371           print_longest (stream, 'd', 0, val);
 372         }
 373       break;
 374
 375     case TYPE_CODE_FLAGS:
 376       if (format)
 377           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 378       else
 379         val_print_type_code_flags (type, valaddr + embedded_offset, stream);
 380       break;
 381
 382     case TYPE_CODE_FUNC:
 383     case TYPE_CODE_METHOD:
 384       if (format)
 385         {
 386           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 387           break;
 388         }
 389       /* FIXME, we should consider, at least for ANSI C language, eliminating
 390          the distinction made between FUNCs and POINTERs to FUNCs.  */
 391       fprintf_filtered (stream, "{");
 392       type_print (type, "", stream, -1);
 393       fprintf_filtered (stream, "} ");
 394       /* Try to print what function it points to, and its address.  */
 395       print_address_demangle (address, stream, demangle);
 396       break;
 397
 398     case TYPE_CODE_BOOL:
 399       format = format ? format : output_format;
 400       if (format)
 401         print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 402       else
 403         {
 404           val = unpack_long (type, valaddr + embedded_offset);
 405           if (val == 0)
 406             fputs_filtered ("false", stream);
 407           else if (val == 1)
 408             fputs_filtered ("true", stream);
 409           else
 410             print_longest (stream, 'd', 0, val);
 411         }
 412       break;
 413
 414     case TYPE_CODE_RANGE:
 415       /* FIXME: create_range_type does not set the unsigned bit in a
 416          range type (I think it probably should copy it from the target
 417          type), so we won't print values which are too large to
 418          fit in a signed integer correctly.  */
 419       /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
 420          print with the target type, though, because the size of our type
 421          and the target type might differ).  */
 422       /* FALLTHROUGH */
 423
 424     case TYPE_CODE_INT:
 425       format = format ? format : output_format;
 426       if (format)
 427         {
 428           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 429         }
 430       else
 431         {
 432           val_print_type_code_int (type, valaddr + embedded_offset, stream);
 433           /* C and C++ has no single byte int type, char is used instead.
 434              Since we don't know whether the value is really intended to
 435              be used as an integer or a character, print the character
 436              equivalent as well.  */
 437           if (textual_element_type (type, format))
 438             {
 439               fputs_filtered (" ", stream);
 440               LA_PRINT_CHAR ((unsigned char) unpack_long (type, valaddr + embedded_offset),
 441                              stream);
 442             }
 443         }
 444       break;
 445
 446     case TYPE_CODE_CHAR:
 447       format = format ? format : output_format;
 448       if (format)
 449         {
 450           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 451         }
 452       else
 453         {
 454           val = unpack_long (type, valaddr + embedded_offset);
 455           if (TYPE_UNSIGNED (type))
 456             fprintf_filtered (stream, "%u", (unsigned int) val);
 457           else
 458             fprintf_filtered (stream, "%d", (int) val);
 459           fputs_filtered (" ", stream);
 460           LA_PRINT_CHAR ((unsigned char) val, stream);
 461         }
 462       break;
 463
 464     case TYPE_CODE_FLT:
 465       if (format)
 466         {
 467           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 468         }
 469       else
 470         {
 471           print_floating (valaddr + embedded_offset, type, stream);
 472         }
 473       break;
 474
 475     case TYPE_CODE_DECFLOAT:
 476       if (format)
 477         print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 478       else
 479         print_decimal_floating (valaddr + embedded_offset, type, stream);
 480       break;
 481
 482     case TYPE_CODE_VOID:
 483       fprintf_filtered (stream, "void");
 484       break;
 485
 486     case TYPE_CODE_ERROR:
 487       fprintf_filtered (stream, _("<error type>"));
 488       break;
 489
 490     case TYPE_CODE_UNDEF:
 491       /* This happens (without TYPE_FLAG_STUB set) on systems which don't use
 492          dbx xrefs (NO_DBX_XREFS in gcc) if a file has a "struct foo *bar"
 493          and no complete type for struct foo in that file.  */
 494       fprintf_filtered (stream, _("<incomplete type>"));
 495       break;
 496
 497     case TYPE_CODE_COMPLEX:
 498       if (format)
 499         print_scalar_formatted (valaddr + embedded_offset,
 500                                 TYPE_TARGET_TYPE (type),
 501                                 format, 0, stream);
 502       else
 503         print_floating (valaddr + embedded_offset, TYPE_TARGET_TYPE (type),
 504                         stream);
 505       fprintf_filtered (stream, " + ");
 506       if (format)
 507         print_scalar_formatted (valaddr + embedded_offset
 508                                 + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 509                                 TYPE_TARGET_TYPE (type),
 510                                 format, 0, stream);
 511       else
 512         print_floating (valaddr + embedded_offset
 513                         + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 514                         TYPE_TARGET_TYPE (type),
 515                         stream);
 516       fprintf_filtered (stream, " * I");
 517       break;
 518
 519     default:
 520       error (_("Invalid C/C++ type code %d in symbol table."), TYPE_CODE (type));
 521     }
 522   gdb_flush (stream);
 523   return (0);
 524 }
 525 \f
 526 int
 527 c_value_print (struct value *val, struct ui_file *stream, int format,
 528                enum val_prettyprint pretty)
 529 {
 530   struct type *type, *real_type;
 531   int full, top, using_enc;
 532
 533   /* If it is a pointer, indicate what it points to.
 534
 535      Print type also if it is a reference.
 536
 537      C++: if it is a member pointer, we will take care
 538      of that when we print it.  */
 539
 540   type = check_typedef (value_type (val));
 541
 542   if (TYPE_CODE (type) == TYPE_CODE_PTR
 543       || TYPE_CODE (type) == TYPE_CODE_REF)
 544     {
 545       /* Hack:  remove (char *) for char strings.  Their
 546          type is indicated by the quoted string anyway.
 547          (Don't use textual_element_type here; quoted strings
 548          are always exactly (char *).  */
 549       if (TYPE_CODE (type) == TYPE_CODE_PTR
 550           && TYPE_NAME (type) == NULL
 551           && TYPE_NAME (TYPE_TARGET_TYPE (type)) != NULL
 552           && strcmp (TYPE_NAME (TYPE_TARGET_TYPE (type)), "char") == 0)
 553         {
 554           /* Print nothing */
 555         }
 556       else if (objectprint && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 557         {
 558
 559           if (TYPE_CODE(type) == TYPE_CODE_REF)
 560             {
 561               /* Copy value, change to pointer, so we don't get an
 562                * error about a non-pointer type in value_rtti_target_type
 563                */
 564               struct value *temparg;
 565               temparg=value_copy(val);
 566               deprecated_set_value_type (temparg, lookup_pointer_type (TYPE_TARGET_TYPE(type)));
 567               val=temparg;
 568             }
 569           /* Pointer to class, check real type of object */
 570           fprintf_filtered (stream, "(");
 571           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 572           if (real_type)
 573             {
 574               /* RTTI entry found */
 575               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 576                 {
 577                   /* create a pointer type pointing to the real type */
 578                   type = lookup_pointer_type (real_type);
 579                 }
 580               else
 581                 {
 582                   /* create a reference type referencing the real type */
 583                   type = lookup_reference_type (real_type);
 584                 }
 585               /* JYG: Need to adjust pointer value. */
 586               /* NOTE: cagney/2005-01-02: THIS IS BOGUS.  */
 587               value_contents_writeable (val)[0] -= top;
 588
 589               /* Note: When we look up RTTI entries, we don't get any
 590                  information on const or volatile attributes */
 591             }
 592           type_print (type, "", stream, -1);
 593           fprintf_filtered (stream, ") ");
 594         }
 595       else
 596         {
 597           /* normal case */
 598           fprintf_filtered (stream, "(");
 599           type_print (value_type (val), "", stream, -1);
 600           fprintf_filtered (stream, ") ");
 601         }
 602     }
 603
 604   if (!value_initialized (val))
 605     fprintf_filtered (stream, " [uninitialized] ");
 606
 607   if (objectprint && (TYPE_CODE (type) == TYPE_CODE_CLASS))
 608     {
 609       /* Attempt to determine real type of object */
 610       real_type = value_rtti_type (val, &full, &top, &using_enc);
 611       if (real_type)
 612         {
 613           /* We have RTTI information, so use it */
 614           val = value_full_object (val, real_type, full, top, using_enc);
 615           fprintf_filtered (stream, "(%s%s) ",
 616                             TYPE_NAME (real_type),
 617                             full ? "" : _(" [incomplete object]"));
 618           /* Print out object: enclosing type is same as real_type if full */
 619           return val_print (value_enclosing_type (val),
 620                             value_contents_all (val), 0,
 621                             VALUE_ADDRESS (val), stream, format, 1, 0,
 622                             pretty, current_language);
 623           /* Note: When we look up RTTI entries, we don't get any information on
 624              const or volatile attributes */
 625         }
 626       else if (type != check_typedef (value_enclosing_type (val)))
 627         {
 628           /* No RTTI information, so let's do our best */
 629           fprintf_filtered (stream, "(%s ?) ",
 630                             TYPE_NAME (value_enclosing_type (val)));
 631           return val_print (value_enclosing_type (val),
 632                             value_contents_all (val), 0,
 633                             VALUE_ADDRESS (val), stream, format, 1, 0,
 634                             pretty, current_language);
 635         }
 636       /* Otherwise, we end up at the return outside this "if" */
 637     }
 638
 639   return val_print (type, value_contents_all (val),
 640                     value_embedded_offset (val),
 641                     VALUE_ADDRESS (val) + value_offset (val),
 642                     stream, format, 1, 0, pretty, current_language);
 643 }