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