gdb/c-valprint.c

   1 /* Support for printing C values for GDB, the GNU debugger.
   2    Copyright 1986, 1988, 1989, 1991-1997, 2000
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "symtab.h"
  24 #include "gdbtypes.h"
  25 #include "expression.h"
  26 #include "value.h"
  27 #include "demangle.h"
  28 #include "valprint.h"
  29 #include "language.h"
  30 #include "c-lang.h"
  31 \f
  32
  33 /* Print function pointer with inferior address ADDRESS onto stdio
  34    stream STREAM.  */
  35
  36 static void
  37 print_function_pointer_address (CORE_ADDR address, struct ui_file *stream)
  38 {
  39   CORE_ADDR func_addr = CONVERT_FROM_FUNC_PTR_ADDR (address);
  40
  41   /* If the function pointer is represented by a description, print the
  42      address of the description.  */
  43   if (addressprint && func_addr != address)
  44     {
  45       fputs_filtered ("@", stream);
  46       print_address_numeric (address, 1, stream);
  47       fputs_filtered (": ", stream);
  48     }
  49   print_address_demangle (func_addr, stream, demangle);
  50 }
  51
  52
  53 /* Print data of type TYPE located at VALADDR (within GDB), which came from
  54    the inferior at address ADDRESS, onto stdio stream STREAM according to
  55    FORMAT (a letter or 0 for natural format).  The data at VALADDR is in
  56    target byte order.
  57
  58    If the data are a string pointer, returns the number of string characters
  59    printed.
  60
  61    If DEREF_REF is nonzero, then dereference references, otherwise just print
  62    them like pointers.
  63
  64    The PRETTY parameter controls prettyprinting.  */
  65
  66 int
  67 c_val_print (struct type *type, char *valaddr, int embedded_offset,
  68              CORE_ADDR address, struct ui_file *stream, int format,
  69              int deref_ref, int recurse, enum val_prettyprint pretty)
  70 {
  71   register unsigned int i = 0;  /* Number of characters printed */
  72   unsigned len;
  73   struct type *elttype;
  74   unsigned eltlen;
  75   LONGEST val;
  76   CORE_ADDR addr;
  77
  78   CHECK_TYPEDEF (type);
  79   switch (TYPE_CODE (type))
  80     {
  81     case TYPE_CODE_ARRAY:
  82       elttype = check_typedef (TYPE_TARGET_TYPE (type));
  83       if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (TYPE_TARGET_TYPE (type)) > 0)
  84         {
  85           eltlen = TYPE_LENGTH (elttype);
  86           len = TYPE_LENGTH (type) / eltlen;
  87           if (prettyprint_arrays)
  88             {
  89               print_spaces_filtered (2 + 2 * recurse, stream);
  90             }
  91           /* For an array of chars, print with string syntax.  */
  92           if (eltlen == 1 &&
  93               ((TYPE_CODE (elttype) == TYPE_CODE_INT)
  94                || ((current_language->la_language == language_m2)
  95                    && (TYPE_CODE (elttype) == TYPE_CODE_CHAR)))
  96               && (format == 0 || format == 's'))
  97             {
  98               /* If requested, look for the first null char and only print
  99                  elements up to it.  */
 100               if (stop_print_at_null)
 101                 {
 102                   unsigned int temp_len;
 103
 104                   /* Look for a NULL char. */
 105                   for (temp_len = 0;
 106                        (valaddr + embedded_offset)[temp_len]
 107                        && temp_len < len && temp_len < print_max;
 108                        temp_len++);
 109                   len = temp_len;
 110                 }
 111
 112               LA_PRINT_STRING (stream, valaddr + embedded_offset, len, eltlen, 0);
 113               i = len;
 114             }
 115           else
 116             {
 117               fprintf_filtered (stream, "{");
 118               /* If this is a virtual function table, print the 0th
 119                  entry specially, and the rest of the members normally.  */
 120               if (cp_is_vtbl_ptr_type (elttype))
 121                 {
 122                   i = 1;
 123                   fprintf_filtered (stream, "%d vtable entries", len - 1);
 124                 }
 125               else
 126                 {
 127                   i = 0;
 128                 }
 129               val_print_array_elements (type, valaddr + embedded_offset, address, stream,
 130                                      format, deref_ref, recurse, pretty, i);
 131               fprintf_filtered (stream, "}");
 132             }
 133           break;
 134         }
 135       /* Array of unspecified length: treat like pointer to first elt.  */
 136       addr = address;
 137       goto print_unpacked_pointer;
 138
 139     case TYPE_CODE_PTR:
 140       if (format && format != 's')
 141         {
 142           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 143           break;
 144         }
 145       if (vtblprint && cp_is_vtbl_ptr_type (type))
 146         {
 147           /* Print the unmangled name if desired.  */
 148           /* Print vtable entry - we only get here if we ARE using
 149              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_STRUCT.) */
 150           CORE_ADDR addr
 151             = extract_typed_address (valaddr + embedded_offset, type);
 152           print_function_pointer_address (addr, stream);
 153           break;
 154         }
 155       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 156       if (TYPE_CODE (elttype) == TYPE_CODE_METHOD)
 157         {
 158           cp_print_class_method (valaddr + embedded_offset, type, stream);
 159         }
 160       else if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
 161         {
 162           cp_print_class_member (valaddr + embedded_offset,
 163                                  TYPE_DOMAIN_TYPE (TYPE_TARGET_TYPE (type)),
 164                                  stream, "&");
 165         }
 166       else
 167         {
 168           addr = unpack_pointer (type, valaddr + embedded_offset);
 169         print_unpacked_pointer:
 170           elttype = check_typedef (TYPE_TARGET_TYPE (type));
 171
 172           if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
 173             {
 174               /* Try to print what function it points to.  */
 175               print_function_pointer_address (addr, stream);
 176               /* Return value is irrelevant except for string pointers.  */
 177               return (0);
 178             }
 179
 180           if (addressprint && format != 's')
 181             {
 182               print_address_numeric (addr, 1, stream);
 183             }
 184
 185           /* For a pointer to char or unsigned char, also print the string
 186              pointed to, unless pointer is null.  */
 187           /* FIXME: need to handle wchar_t here... */
 188
 189           if (TYPE_LENGTH (elttype) == 1
 190               && TYPE_CODE (elttype) == TYPE_CODE_INT
 191               && (format == 0 || format == 's')
 192               && addr != 0)
 193             {
 194               i = val_print_string (addr, -1, TYPE_LENGTH (elttype), stream);
 195             }
 196           else if (cp_is_vtbl_member (type))
 197             {
 198               /* print vtbl's nicely */
 199               CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
 200
 201               struct minimal_symbol *msymbol =
 202               lookup_minimal_symbol_by_pc (vt_address);
 203               if ((msymbol != NULL) &&
 204                   (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
 205                 {
 206                   fputs_filtered (" <", stream);
 207                   fputs_filtered (SYMBOL_SOURCE_NAME (msymbol), stream);
 208                   fputs_filtered (">", stream);
 209                 }
 210               if (vt_address && vtblprint)
 211                 {
 212                   value_ptr vt_val;
 213                   struct symbol *wsym = (struct symbol *) NULL;
 214                   struct type *wtype;
 215                   struct symtab *s;
 216                   struct block *block = (struct block *) NULL;
 217                   int is_this_fld;
 218
 219                   if (msymbol != NULL)
 220                     wsym = lookup_symbol (SYMBOL_NAME (msymbol), block,
 221                                           VAR_NAMESPACE, &is_this_fld, &s);
 222
 223                   if (wsym)
 224                     {
 225                       wtype = SYMBOL_TYPE (wsym);
 226                     }
 227                   else
 228                     {
 229                       wtype = TYPE_TARGET_TYPE (type);
 230                     }
 231                   vt_val = value_at (wtype, vt_address, NULL);
 232                   val_print (VALUE_TYPE (vt_val), VALUE_CONTENTS (vt_val), 0,
 233                              VALUE_ADDRESS (vt_val), stream, format,
 234                              deref_ref, recurse + 1, pretty);
 235                   if (pretty)
 236                     {
 237                       fprintf_filtered (stream, "\n");
 238                       print_spaces_filtered (2 + 2 * recurse, stream);
 239                     }
 240                 }
 241             }
 242
 243           /* Return number of characters printed, including the terminating
 244              '\0' if we reached the end.  val_print_string takes care including
 245              the terminating '\0' if necessary.  */
 246           return i;
 247         }
 248       break;
 249
 250     case TYPE_CODE_MEMBER:
 251       error ("not implemented: member type in c_val_print");
 252       break;
 253
 254     case TYPE_CODE_REF:
 255       elttype = check_typedef (TYPE_TARGET_TYPE (type));
 256       if (TYPE_CODE (elttype) == TYPE_CODE_MEMBER)
 257         {
 258           cp_print_class_member (valaddr + embedded_offset,
 259                                  TYPE_DOMAIN_TYPE (elttype),
 260                                  stream, "");
 261           break;
 262         }
 263       if (addressprint)
 264         {
 265           CORE_ADDR addr
 266             = extract_typed_address (valaddr + embedded_offset, type);
 267           fprintf_filtered (stream, "@");
 268           print_address_numeric (addr, 1, stream);
 269           if (deref_ref)
 270             fputs_filtered (": ", stream);
 271         }
 272       /* De-reference the reference.  */
 273       if (deref_ref)
 274         {
 275           if (TYPE_CODE (elttype) != TYPE_CODE_UNDEF)
 276             {
 277               value_ptr deref_val =
 278               value_at
 279               (TYPE_TARGET_TYPE (type),
 280                unpack_pointer (lookup_pointer_type (builtin_type_void),
 281                                valaddr + embedded_offset),
 282                NULL);
 283               val_print (VALUE_TYPE (deref_val),
 284                          VALUE_CONTENTS (deref_val),
 285                          0,
 286                          VALUE_ADDRESS (deref_val),
 287                          stream,
 288                          format,
 289                          deref_ref,
 290                          recurse,
 291                          pretty);
 292             }
 293           else
 294             fputs_filtered ("???", stream);
 295         }
 296       break;
 297
 298     case TYPE_CODE_UNION:
 299       if (recurse && !unionprint)
 300         {
 301           fprintf_filtered (stream, "{...}");
 302           break;
 303         }
 304       /* Fall through.  */
 305     case TYPE_CODE_STRUCT:
 306       if (vtblprint && cp_is_vtbl_ptr_type (type))
 307         {
 308           /* Print the unmangled name if desired.  */
 309           /* Print vtable entry - we only get here if NOT using
 310              -fvtable_thunks.  (Otherwise, look under TYPE_CODE_PTR.) */
 311           int offset = (embedded_offset +
 312                         TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
 313           struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
 314           CORE_ADDR addr
 315             = extract_typed_address (valaddr + offset, field_type);
 316
 317           print_function_pointer_address (addr, stream);
 318         }
 319       else
 320         cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream, format,
 321                                recurse, pretty, NULL, 0);
 322       break;
 323
 324     case TYPE_CODE_ENUM:
 325       if (format)
 326         {
 327           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 328           break;
 329         }
 330       len = TYPE_NFIELDS (type);
 331       val = unpack_long (type, valaddr + embedded_offset);
 332       for (i = 0; i < len; i++)
 333         {
 334           QUIT;
 335           if (val == TYPE_FIELD_BITPOS (type, i))
 336             {
 337               break;
 338             }
 339         }
 340       if (i < len)
 341         {
 342           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 343         }
 344       else
 345         {
 346           print_longest (stream, 'd', 0, val);
 347         }
 348       break;
 349
 350     case TYPE_CODE_FUNC:
 351       if (format)
 352         {
 353           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 354           break;
 355         }
 356       /* FIXME, we should consider, at least for ANSI C language, eliminating
 357          the distinction made between FUNCs and POINTERs to FUNCs.  */
 358       fprintf_filtered (stream, "{");
 359       type_print (type, "", stream, -1);
 360       fprintf_filtered (stream, "} ");
 361       /* Try to print what function it points to, and its address.  */
 362       print_address_demangle (address, stream, demangle);
 363       break;
 364
 365     case TYPE_CODE_BOOL:
 366       format = format ? format : output_format;
 367       if (format)
 368         print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 369       else
 370         {
 371           val = unpack_long (type, valaddr + embedded_offset);
 372           if (val == 0)
 373             fputs_filtered ("false", stream);
 374           else if (val == 1)
 375             fputs_filtered ("true", stream);
 376           else
 377             print_longest (stream, 'd', 0, val);
 378         }
 379       break;
 380
 381     case TYPE_CODE_RANGE:
 382       /* FIXME: create_range_type does not set the unsigned bit in a
 383          range type (I think it probably should copy it from the target
 384          type), so we won't print values which are too large to
 385          fit in a signed integer correctly.  */
 386       /* FIXME: Doesn't handle ranges of enums correctly.  (Can't just
 387          print with the target type, though, because the size of our type
 388          and the target type might differ).  */
 389       /* FALLTHROUGH */
 390
 391     case TYPE_CODE_INT:
 392       format = format ? format : output_format;
 393       if (format)
 394         {
 395           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 396         }
 397       else
 398         {
 399           val_print_type_code_int (type, valaddr + embedded_offset, stream);
 400           /* C and C++ has no single byte int type, char is used instead.
 401              Since we don't know whether the value is really intended to
 402              be used as an integer or a character, print the character
 403              equivalent as well. */
 404           if (TYPE_LENGTH (type) == 1)
 405             {
 406               fputs_filtered (" ", stream);
 407               LA_PRINT_CHAR ((unsigned char) unpack_long (type, valaddr + embedded_offset),
 408                              stream);
 409             }
 410         }
 411       break;
 412
 413     case TYPE_CODE_CHAR:
 414       format = format ? format : output_format;
 415       if (format)
 416         {
 417           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 418         }
 419       else
 420         {
 421           val = unpack_long (type, valaddr + embedded_offset);
 422           if (TYPE_UNSIGNED (type))
 423             fprintf_filtered (stream, "%u", (unsigned int) val);
 424           else
 425             fprintf_filtered (stream, "%d", (int) val);
 426           fputs_filtered (" ", stream);
 427           LA_PRINT_CHAR ((unsigned char) val, stream);
 428         }
 429       break;
 430
 431     case TYPE_CODE_FLT:
 432       if (format)
 433         {
 434           print_scalar_formatted (valaddr + embedded_offset, type, format, 0, stream);
 435         }
 436       else
 437         {
 438           print_floating (valaddr + embedded_offset, type, stream);
 439         }
 440       break;
 441
 442     case TYPE_CODE_METHOD:
 443       cp_print_class_method (valaddr + embedded_offset, lookup_pointer_type (type), stream);
 444       break;
 445
 446     case TYPE_CODE_VOID:
 447       fprintf_filtered (stream, "void");
 448       break;
 449
 450     case TYPE_CODE_ERROR:
 451       fprintf_filtered (stream, "<error type>");
 452       break;
 453
 454     case TYPE_CODE_UNDEF:
 455       /* This happens (without TYPE_FLAG_STUB set) on systems which don't use
 456          dbx xrefs (NO_DBX_XREFS in gcc) if a file has a "struct foo *bar"
 457          and no complete type for struct foo in that file.  */
 458       fprintf_filtered (stream, "<incomplete type>");
 459       break;
 460
 461     default:
 462       error ("Invalid C/C++ type code %d in symbol table.", TYPE_CODE (type));
 463     }
 464   gdb_flush (stream);
 465   return (0);
 466 }
 467 \f
 468 int
 469 c_value_print (value_ptr val, struct ui_file *stream, int format,
 470                enum val_prettyprint pretty)
 471 {
 472   struct type *type = VALUE_TYPE (val);
 473   struct type *real_type;
 474   int full, top, using_enc;
 475
 476   /* If it is a pointer, indicate what it points to.
 477
 478      Print type also if it is a reference.
 479
 480      C++: if it is a member pointer, we will take care
 481      of that when we print it.  */
 482   if (TYPE_CODE (type) == TYPE_CODE_PTR ||
 483       TYPE_CODE (type) == TYPE_CODE_REF)
 484     {
 485       /* Hack:  remove (char *) for char strings.  Their
 486          type is indicated by the quoted string anyway. */
 487       if (TYPE_CODE (type) == TYPE_CODE_PTR &&
 488           TYPE_NAME (type) == NULL &&
 489           TYPE_NAME (TYPE_TARGET_TYPE (type)) != NULL &&
 490           STREQ (TYPE_NAME (TYPE_TARGET_TYPE (type)), "char"))
 491         {
 492           /* Print nothing */
 493         }
 494       else if (objectprint && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 495         {
 496
 497           if (TYPE_CODE(type) == TYPE_CODE_REF)
 498             {
 499               /* Copy value, change to pointer, so we don't get an
 500                * error about a non-pointer type in value_rtti_target_type
 501                */
 502               value_ptr temparg;
 503               temparg=value_copy(val);
 504               VALUE_TYPE (temparg) = lookup_pointer_type(TYPE_TARGET_TYPE(type));
 505               val=temparg;
 506             }
 507           /* Pointer to class, check real type of object */
 508           fprintf_filtered (stream, "(");
 509           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 510           if (real_type)
 511             {
 512               /* RTTI entry found */
 513               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 514                 {
 515                   /* create a pointer type pointing to the real type */
 516                   type = lookup_pointer_type (real_type);
 517                 }
 518               else
 519                 {
 520                   /* create a reference type referencing the real type */
 521                   type = lookup_reference_type (real_type);
 522                 }
 523               /* JYG: Need to adjust pointer value. */
 524               val->aligner.contents[0] -= top;
 525
 526               /* Note: When we look up RTTI entries, we don't get any
 527                  information on const or volatile attributes */
 528             }
 529           type_print (type, "", stream, -1);
 530           fprintf_filtered (stream, ") ");
 531         }
 532       else
 533         {
 534           /* normal case */
 535           fprintf_filtered (stream, "(");
 536           type_print (type, "", stream, -1);
 537           fprintf_filtered (stream, ") ");
 538         }
 539     }
 540   if (objectprint && (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_CLASS))
 541     {
 542       /* Attempt to determine real type of object */
 543       real_type = value_rtti_type (val, &full, &top, &using_enc);
 544       if (real_type)
 545         {
 546           /* We have RTTI information, so use it */
 547           val = value_full_object (val, real_type, full, top, using_enc);
 548           fprintf_filtered (stream, "(%s%s) ",
 549                             TYPE_NAME (real_type),
 550                             full ? "" : " [incomplete object]");
 551           /* Print out object: enclosing type is same as real_type if full */
 552           return val_print (VALUE_ENCLOSING_TYPE (val), VALUE_CONTENTS_ALL (val), 0,
 553                          VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 554           /* Note: When we look up RTTI entries, we don't get any information on
 555              const or volatile attributes */
 556         }
 557       else if (type != VALUE_ENCLOSING_TYPE (val))
 558         {
 559           /* No RTTI information, so let's do our best */
 560           fprintf_filtered (stream, "(%s ?) ",
 561                             TYPE_NAME (VALUE_ENCLOSING_TYPE (val)));
 562           return val_print (VALUE_ENCLOSING_TYPE (val), VALUE_CONTENTS_ALL (val), 0,
 563                          VALUE_ADDRESS (val), stream, format, 1, 0, pretty);
 564         }
 565       /* Otherwise, we end up at the return outside this "if" */
 566     }
 567
 568   return val_print (type, VALUE_CONTENTS_ALL (val), VALUE_EMBEDDED_OFFSET (val),
 569                     VALUE_ADDRESS (val),
 570                     stream, format, 1, 0, pretty);
 571 }