gdb/c-valprint.c

   1 /* Support for printing C values for GDB, the GNU debugger.
   2    Copyright 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
   3    1998, 1999, 2000, 2001
   4    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 \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 = CONVERT_FROM_FUNC_PTR_ADDR (address);
  42
  43   /* If the function pointer is represented by a description, print the
  44      address of the description.  */
  45   if (addressprint && func_addr != address)
  46     {
  47       fputs_filtered ("@", stream);
  48       print_address_numeric (address, 1, stream);
  49       fputs_filtered (": ", stream);
  50     }
  51   print_address_demangle (func_addr, stream, demangle);
  52 }
  53
  54
  55 /* Print data of type TYPE located at VALADDR (within GDB), which came from
  56    the inferior at address ADDRESS, onto stdio stream STREAM according to
  57    FORMAT (a letter or 0 for natural format).  The data at VALADDR is in
  58    target byte order.
  59
  60    If the data are a string pointer, returns the number of string characters
  61    printed.
  62
  63    If DEREF_REF is nonzero, then dereference references, otherwise just print
  64    them like pointers.
  65
  66    The PRETTY parameter controls prettyprinting.  */
  67
  68 int
  69 c_val_print (struct type *type, char *valaddr, int embedded_offset,
  70              CORE_ADDR address, struct ui_file *stream, int format,
  71              int deref_ref, int recurse, enum val_prettyprint pretty)
  72 {
  73   register unsigned int i = 0;  /* Number of characters printed */
  74   unsigned len;
  75   struct type *elttype;
  76   unsigned eltlen;
  77   LONGEST val;
  78   CORE_ADDR addr;
  79
  80   CHECK_TYPEDEF (type);
  81   switch (TYPE_CODE (type))
  82     {
  83     case TYPE_CODE_ARRAY:
  84       elttype = check_typedef (TYPE_TARGET_TYPE (type));
  85       if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (TYPE_TARGET_TYPE (type)) > 0)
  86         {
  87           eltlen = TYPE_LENGTH (elttype);
  88           len = TYPE_LENGTH (type) / eltlen;
  89           if (prettyprint_arrays)
  90             {
  91               print_spaces_filtered (2 + 2 * recurse, stream);
  92             }
  93           /* For an array of chars, print with string syntax.  */
  94           if (eltlen == 1 &&
  95               ((TYPE_CODE (elttype) == TYPE_CODE_INT)
  96                || ((current_language->la_language == language_m2)
  97                    && (TYPE_CODE (elttype) == TYPE_CODE_CHAR)))
  98               && (format == 0 || format == 's'))
  99             {
 100               /* If requested, look for the first null char and only print
 101                  elements up to it.  */
 102               if (stop_print_at_null)
 103                 {
 104                   unsigned int temp_len;
 105
 106                   /* Look for a NULL char. */
 107                   for (temp_len = 0;
 108                        (valaddr + embedded_offset)[temp_len]
 109                        && temp_len < len && temp_len < print_max;
 110                        temp_len++);
 111                   len = temp_len;
 112                 }
 113
 114               LA_PRINT_STRING (stream, valaddr + embedded_offset, len, eltlen, 0);
 115               i = len;
 116             }
 117           else
 118             {
 119               fprintf_filtered (stream, "{");
 120               /* If this is a virtual function table, print the 0th
 121                  entry specially, and the rest of the members normally.  */
 122               if (cp_is_vtbl_ptr_type (elttype))
 123                 {
 124                   i = 1;
 125                   fprintf_filtered (stream, "%d vtable entries", len - 1);
 126                 }
 127               else
 128                 {
 129                   i = 0;
 130                 }
 131               val_print_array_elements (type, valaddr + embedded_offset, address, stream,
 132                                      format, deref_ref, recurse, pretty, i);
 133               fprintf_filtered (stream, "}");
 134             }
 135           break;
 136         }
 137       /* Array of unspecified length: treat like pointer to first elt.  */
 138       addr = address;
 139       goto print_unpacked_pointer;
 140
 141     case TYPE_CODE_PTR:
 142       if (format && format != 's')
 143         {
 144           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 145           break;
 146         }
 147       if (vtblprint && cp_is_vtbl_ptr_type (type))
 148         {
 149           /* Print the unmangled name if desired.  */
 150           /* Print vtable entry - we only get here if we ARE using
 151              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_STRUCT.) */
 152           CORE_ADDR addr
 153             = extract_typed_address (valaddr + embedded_offset, type);
 154           print_function_pointer_address (addr, stream);
 155           break;
 156         }
 157       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 158       if (TYPE_CODE (elttype) == TYPE_CODE_METHOD)
 159         {
 160           cp_print_class_method (valaddr + embedded_offset, type, stream);
 161         }
 162       else if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
 163         {
 164           cp_print_class_member (valaddr + embedded_offset,
 165                                  TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (type)),
 166                                  stream, "&");
 167         }
 168       else
 169         {
 170           addr = unpack_pointer (type, valaddr + embedded_offset);
 171         print_unpacked_pointer:
 172
 173           if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
 174             {
 175               /* Try to print what function it points to.  */
 176               print_function_pointer_address (addr, stream);
 177               /* Return value is irrelevant except for string pointers.  */
 178               return (0);
 179             }
 180
 181           if (addressprint && format != 's')
 182             {
 183               print_address_numeric (addr, 1, stream);
 184             }
 185
 186           /* For a pointer to char or unsigned char, also print the string
 187              pointed to, unless pointer is null.  */
 188           /* FIXME: need to handle wchar_t here... */
 189
 190           if (TYPE_LENGTH (elttype) == 1
 191               && TYPE_CODE (elttype) == TYPE_CODE_INT
 192               && (format == 0 || format == 's')
 193               && addr != 0)
 194             {
 195               i = val_print_string (addr, -1, TYPE_LENGTH (elttype), stream);
 196             }
 197           else if (cp_is_vtbl_member (type))
 198             {
 199               /* print vtbl's nicely */
 200               CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
 201
 202               struct minimal_symbol *msymbol =
 203               lookup_minimal_symbol_by_pc (vt_address);
 204               if ((msymbol != NULL) &&
 205                   (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
 206                 {
 207                   fputs_filtered (" <", stream);
 208                   fputs_filtered (SYMBOL_SOURCE_NAME (msymbol), stream);
 209                   fputs_filtered (">", stream);
 210                 }
 211               if (vt_address && vtblprint)
 212                 {
 213                   struct value *vt_val;
 214                   struct symbol *wsym = (struct symbol *) NULL;
 215                   struct type *wtype;
 216                   struct symtab *s;
 217                   struct block *block = (struct block *) NULL;
 218                   int is_this_fld;
 219
 220                   if (msymbol != NULL)
 221                     wsym = lookup_symbol (SYMBOL_NAME (msymbol), block,
 222                                           VAR_NAMESPACE, &is_this_fld, &s);
 223
 224                   if (wsym)
 225                     {
 226                       wtype = SYMBOL_TYPE (wsym);
 227                     }
 228                   else
 229                     {
 230                       wtype = TYPE_TARGET_TYPE (type);
 231                     }
 232                   vt_val = value_at (wtype, vt_address, NULL);
 233                   val_print (VALUE_TYPE (vt_val), VALUE_CONTENTS (vt_val), 0,
 234                              VALUE_ADDRESS (vt_val), stream, format,
 235                              deref_ref, recurse + 1, pretty);
 236                   if (pretty)
 237                     {
 238                       fprintf_filtered (stream, "\n");
 239                       print_spaces_filtered (2 + 2 * recurse, stream);
 240                     }
 241                 }
 242             }
 243
 244           /* Return number of characters printed, including the terminating
 245              '\0' if we reached the end.  val_print_string takes care including
 246              the terminating '\0' if necessary.  */
 247           return i;
 248         }
 249       break;
 250
 251     case TYPE_CODE_MEMBER:
 252       error ("not implemented: member type in c_val_print");
 253       break;
 254
 255     case TYPE_CODE_REF:
 256       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 257       if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
 258         {
 259           cp_print_class_member (valaddr + embedded_offset,
 260                                  TYPE_DOMAIN_TYPE (elttype),
 261                                  stream, "");
 262           break;
 263         }
 264       if (addressprint)
 265         {
 266           CORE_ADDR addr
 267             = extract_typed_address (valaddr + embedded_offset, type);
 268           fprintf_filtered (stream, "@");
 269           print_address_numeric (addr, 1, stream);
 270           if (deref_ref)
 271             fputs_filtered (": ", stream);
 272         }
 273       /* De-reference the reference.  */
 274       if (deref_ref)
 275         {
 276           if (TYPE_CODE (elttype) != TYPE_CODE_UNDEF)
 277             {
 278               struct value *deref_val =
 279               value_at
 280               (TYPE_TARGET_TYPE (type),
 281                unpack_pointer (lookup_pointer_type (builtin_type_void),
 282                                valaddr + embedded_offset),
 283                NULL);
 284               val_print (VALUE_TYPE (deref_val),
 285                          VALUE_CONTENTS (deref_val),
 286                          0,
 287                          VALUE_ADDRESS (deref_val),
 288                          stream,
 289                          format,
 290                          deref_ref,
 291                          recurse,
 292                          pretty);
 293             }
 294           else
 295             fputs_filtered ("???", stream);
 296         }
 297       break;
 298
 299     case TYPE_CODE_UNION:
 300       if (recurse && !unionprint)
 301         {
 302           fprintf_filtered (stream, "{...}");
 303           break;
 304         }
 305       /* Fall through.  */
 306     case TYPE_CODE_STRUCT:
 307       /*FIXME: Abstract this away */
 308       if (vtblprint && cp_is_vtbl_ptr_type (type))
 309         {
 310           /* Print the unmangled name if desired.  */
 311           /* Print vtable entry - we only get here if NOT using
 312              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_PTR.) */
 313           int offset = (embedded_offset +
 314                         TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
 315           struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
 316           CORE_ADDR addr
 317             = extract_typed_address (valaddr + offset, field_type);
 318
 319           print_function_pointer_address (addr, stream);
 320         }
 321       else
 322         cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream, format,
 323                                recurse, pretty, NULL, 0);
 324       break;
 325
 326     case TYPE_CODE_ENUM:
 327       if (format)
 328         {
 329           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 330           break;
 331         }
 332       len = TYPE_NFIELDS (type);
 333       val = unpack_long (type, valaddr + embedded_offset);
 334       for (i = 0; i < len; i++)
 335         {
 336           QUIT;
 337           if (val == TYPE_FIELD_BITPOS (type, i))
 338             {
 339               break;
 340             }
 341         }
 342       if (i < len)
 343         {
 344           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 345         }
 346       else
 347         {
 348           print_longest (stream, 'd', 0, val);
 349         }
 350       break;
 351
 352     case TYPE_CODE_FUNC:
 353       if (format)
 354         {
 355           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 356           break;
 357         }
 358       /* FIXME, we should consider, at least for ANSI C language, eliminating
 359          the distinction made between FUNCs and POINTERs to FUNCs.  */
 360       fprintf_filtered (stream, "{");
 361       type_print (type, "", stream, -1);
 362       fprintf_filtered (stream, "} ");
 363       /* Try to print what function it points to, and its address.  */
 364       print_address_demangle (address, stream, demangle);
 365       break;
 366
 367     case TYPE_CODE_BOOL:
 368       format = format ? format : output_format;
 369       if (format)
 370         print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 371       else
 372         {
 373           val = unpack_long (type, valaddr + embedded_offset);
 374           if (val == 0)
 375             fputs_filtered ("false", stream);
 376           else if (val == 1)
 377             fputs_filtered ("true", stream);
 378           else
 379             print_longest (stream, 'd', 0, val);
 380         }
 381       break;
 382
 383     case TYPE_CODE_RANGE:
 384       /* FIXME: create_range_type does not set the unsigned bit in a
 385          range type (I think it probably should copy it from the target
 386          type), so we won't print values which are too large to
 387          fit in a signed integer correctly.  */
 388       /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
 389          print with the target type, though, because the size of our type
 390          and the target type might differ).  */
 391       /* FALLTHROUGH */
 392
 393     case TYPE_CODE_INT:
 394       format = format ? format : output_format;
 395       if (format)
 396         {
 397           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 398         }
 399       else
 400         {
 401           val_print_type_code_int (type, valaddr + embedded_offset, stream);
 402           /* C and C++ has no single byte int type, char is used instead.
 403              Since we don't know whether the value is really intended to
 404              be used as an integer or a character, print the character
 405              equivalent as well. */
 406           if (TYPE_LENGTH (type) == 1)
 407             {
 408               fputs_filtered (" ", stream);
 409               LA_PRINT_CHAR ((unsigned char) unpack_long (type, valaddr + embedded_offset),
 410                              stream);
 411             }
 412         }
 413       break;
 414
 415     case TYPE_CODE_CHAR:
 416       format = format ? format : output_format;
 417       if (format)
 418         {
 419           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 420         }
 421       else
 422         {
 423           val = unpack_long (type, valaddr + embedded_offset);
 424           if (TYPE_UNSIGNED (type))
 425             fprintf_filtered (stream, "%u", (unsigned int) val);
 426           else
 427             fprintf_filtered (stream, "%d", (int) val);
 428           fputs_filtered (" ", stream);
 429           LA_PRINT_CHAR ((unsigned char) val, stream);
 430         }
 431       break;
 432
 433     case TYPE_CODE_FLT:
 434       if (format)
 435         {
 436           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 437         }
 438       else
 439         {
 440           print_floating (valaddr + embedded_offset, type, stream);
 441         }
 442       break;
 443
 444     case TYPE_CODE_METHOD:
 445       {
 446         struct value *v = value_at (type, address, NULL);
 447         cp_print_class_method (VALUE_CONTENTS (value_addr (v)),
 448                                lookup_pointer_type (type), stream);
 449         break;
 450       }
 451
 452     case TYPE_CODE_VOID:
 453       fprintf_filtered (stream, "void");
 454       break;
 455
 456     case TYPE_CODE_ERROR:
 457       fprintf_filtered (stream, "<error type>");
 458       break;
 459
 460     case TYPE_CODE_UNDEF:
 461       /* This happens (without TYPE_FLAG_STUB set) on systems which don't use
 462          dbx xrefs (NO_DBX_XREFS in gcc) if a file has a "struct foo *bar"
 463          and no complete type for struct foo in that file.  */
 464       fprintf_filtered (stream, "<incomplete type>");
 465       break;
 466
 467     case TYPE_CODE_COMPLEX:
 468       if (format)
 469         print_scalar_formatted (valaddr + embedded_offset,
 470                                 TYPE_TARGET_TYPE (type),
 471                                 format, 0, stream);
 472       else
 473         print_floating (valaddr + embedded_offset, TYPE_TARGET_TYPE (type),
 474                         stream);
 475       fprintf_filtered (stream, " + ");
 476       if (format)
 477         print_scalar_formatted (valaddr + embedded_offset
 478                                 + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 479                                 TYPE_TARGET_TYPE (type),
 480                                 format, 0, stream);
 481       else
 482         print_floating (valaddr + embedded_offset
 483                         + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
 484                         TYPE_TARGET_TYPE (type),
 485                         stream);
 486       fprintf_filtered (stream, " * I");
 487       break;
 488
 489     default:
 490       error ("Invalid C/C++ type code %d in symbol table.", TYPE_CODE (type));
 491     }
 492   gdb_flush (stream);
 493   return (0);
 494 }
 495 \f
 496 int
 497 c_value_print (struct value *val, struct ui_file *stream, int format,
 498                enum val_prettyprint pretty)
 499 {
 500   struct type *type = VALUE_TYPE (val);
 501   struct 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   if (TYPE_CODE (type) == TYPE_CODE_PTR ||
 511       TYPE_CODE (type) == TYPE_CODE_REF)
 512     {
 513       /* Hack:  remove (char *) for char strings.  Their
 514          type is indicated by the quoted string anyway. */
 515       if (TYPE_CODE (type) == TYPE_CODE_PTR &&
 516           TYPE_NAME (type) == NULL &&
 517           TYPE_NAME (TYPE_TARGET_TYPE (type)) != NULL &&
 518           strcmp (TYPE_NAME (TYPE_TARGET_TYPE (type)), "char") == 0)
 519         {
 520           /* Print nothing */
 521         }
 522       else if (objectprint && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 523         {
 524
 525           if (TYPE_CODE(type) == TYPE_CODE_REF)
 526             {
 527               /* Copy value, change to pointer, so we don't get an
 528                * error about a non-pointer type in value_rtti_target_type
 529                */
 530               struct value *temparg;
 531               temparg=value_copy(val);
 532               VALUE_TYPE (temparg) = lookup_pointer_type(TYPE_TARGET_TYPE(type));
 533               val=temparg;
 534             }
 535           /* Pointer to class, check real type of object */
 536           fprintf_filtered (stream, "(");
 537           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 538           if (real_type)
 539             {
 540               /* RTTI entry found */
 541               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 542                 {
 543                   /* create a pointer type pointing to the real type */
 544                   type = lookup_pointer_type (real_type);
 545                 }
 546               else
 547                 {
 548                   /* create a reference type referencing the real type */
 549                   type = lookup_reference_type (real_type);
 550                 }
 551               /* JYG: Need to adjust pointer value. */
 552               val->aligner.contents[0] -= top;
 553
 554               /* Note: When we look up RTTI entries, we don't get any
 555                  information on const or volatile attributes */
 556             }
 557           type_print (type, "", stream, -1);
 558           fprintf_filtered (stream, ") ");
 559         }
 560       else
 561         {
 562           /* normal case */
 563           fprintf_filtered (stream, "(");
 564           type_print (type, "", stream, -1);
 565           fprintf_filtered (stream, ") ");
 566         }
 567     }
 568   if (objectprint && (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_CLASS))
 569     {
 570       /* Attempt to determine real type of object */
 571       real_type = value_rtti_type (val, &full, &top, &using_enc);
 572       if (real_type)
 573         {
 574           /* We have RTTI information, so use it */
 575           val = value_full_object (val, real_type, full, top, using_enc);
 576           fprintf_filtered (stream, "(%s%s) ",
 577                             TYPE_NAME (real_type),
 578                             full ? "" : " [incomplete object]");
 579           /* Print out object: enclosing type is same as real_type if full */
 580           return val_print (VALUE_ENCLOSING_TYPE (val), VALUE_CONTENTS_ALL (val), 0,
 581                          VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 582           /* Note: When we look up RTTI entries, we don't get any information on
 583              const or volatile attributes */
 584         }
 585       else if (type != VALUE_ENCLOSING_TYPE (val))
 586         {
 587           /* No RTTI information, so let's do our best */
 588           fprintf_filtered (stream, "(%s ?) ",
 589                             TYPE_NAME (VALUE_ENCLOSING_TYPE (val)));
 590           return val_print (VALUE_ENCLOSING_TYPE (val), VALUE_CONTENTS_ALL (val), 0,
 591                          VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 592         }
 593       /* Otherwise, we end up at the return outside this "if" */
 594     }
 595
 596   return val_print (type, VALUE_CONTENTS_ALL (val), VALUE_EMBEDDED_OFFSET (val),
 597                     VALUE_ADDRESS (val),
 598                     stream, format, 1, 0, pretty);
 599 }