gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2
   3    Copyright 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1998,
   4    1999, 2000, 2001, 2003 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "gdb_obstack.h"
  25 #include "bfd.h"                /* Binary File Description */
  26 #include "symtab.h"
  27 #include "gdbtypes.h"
  28 #include "expression.h"
  29 #include "value.h"
  30 #include "gdbcore.h"
  31 #include "command.h"
  32 #include "gdbcmd.h"
  33 #include "target.h"
  34 #include "language.h"
  35 #include "cp-abi.h"
  36 #include "typeprint.h"
  37 #include "gdb_string.h"
  38 #include <errno.h>
  39
  40 /* For real-type printing in whatis_exp() */
  41 extern int objectprint;         /* Controls looking up an object's derived type
  42                                    using what we find in its vtables.  */
  43
  44 extern void _initialize_typeprint (void);
  45
  46 static void ptype_command (char *, int);
  47
  48 static struct type *ptype_eval (struct expression *);
  49
  50 static void whatis_command (char *, int);
  51
  52 static void whatis_exp (char *, int);
  53
  54 /* Print a description of a type in the format of a
  55    typedef for the current language.
  56    NEW is the new name for a type TYPE. */
  57
  58 void
  59 typedef_print (struct type *type, struct symbol *new, struct ui_file *stream)
  60 {
  61   CHECK_TYPEDEF (type);
  62   switch (current_language->la_language)
  63     {
  64 #ifdef _LANG_c
  65     case language_c:
  66     case language_cplus:
  67       fprintf_filtered (stream, "typedef ");
  68       type_print (type, "", stream, 0);
  69       if (TYPE_NAME ((SYMBOL_TYPE (new))) == 0
  70           || strcmp (TYPE_NAME ((SYMBOL_TYPE (new))), DEPRECATED_SYMBOL_NAME (new)) != 0)
  71         fprintf_filtered (stream, " %s", SYMBOL_PRINT_NAME (new));
  72       break;
  73 #endif
  74 #ifdef _LANG_m2
  75     case language_m2:
  76       fprintf_filtered (stream, "TYPE ");
  77       if (!TYPE_NAME (SYMBOL_TYPE (new))
  78           || strcmp (TYPE_NAME ((SYMBOL_TYPE (new))), DEPRECATED_SYMBOL_NAME (new)) != 0)
  79         fprintf_filtered (stream, "%s = ", SYMBOL_PRINT_NAME (new));
  80       else
  81         fprintf_filtered (stream, "<builtin> = ");
  82       type_print (type, "", stream, 0);
  83       break;
  84 #endif
  85 #ifdef _LANG_pascal
  86     case language_pascal:
  87       fprintf_filtered (stream, "type ");
  88       fprintf_filtered (stream, "%s = ", SYMBOL_PRINT_NAME (new));
  89       type_print (type, "", stream, 0);
  90       break;
  91 #endif
  92     default:
  93       error ("Language not supported.");
  94     }
  95   fprintf_filtered (stream, ";\n");
  96 }
  97
  98 /* Print a description of a type TYPE in the form of a declaration of a
  99    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
 100    Output goes to STREAM (via stdio).
 101    If SHOW is positive, we show the contents of the outermost level
 102    of structure even if there is a type name that could be used instead.
 103    If SHOW is negative, we never show the details of elements' types.  */
 104
 105 void
 106 type_print (struct type *type, char *varstring, struct ui_file *stream,
 107             int show)
 108 {
 109   LA_PRINT_TYPE (type, varstring, stream, show, 0);
 110 }
 111
 112 /* Print type of EXP, or last thing in value history if EXP == NULL.
 113    show is passed to type_print.  */
 114
 115 static void
 116 whatis_exp (char *exp, int show)
 117 {
 118   struct expression *expr;
 119   struct value *val;
 120   struct cleanup *old_chain = NULL;
 121   struct type *real_type = NULL;
 122   struct type *type;
 123   int full = 0;
 124   int top = -1;
 125   int using_enc = 0;
 126
 127   if (exp)
 128     {
 129       expr = parse_expression (exp);
 130       old_chain = make_cleanup (free_current_contents, &expr);
 131       val = evaluate_type (expr);
 132     }
 133   else
 134     val = access_value_history (0);
 135
 136   type = VALUE_TYPE (val);
 137
 138   if (objectprint)
 139     {
 140       if (((TYPE_CODE (type) == TYPE_CODE_PTR) ||
 141            (TYPE_CODE (type) == TYPE_CODE_REF))
 142           &&
 143           (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 144         {
 145           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 146           if (real_type)
 147             {
 148               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 149                 real_type = lookup_pointer_type (real_type);
 150               else
 151                 real_type = lookup_reference_type (real_type);
 152             }
 153         }
 154       else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
 155   real_type = value_rtti_type (val, &full, &top, &using_enc);
 156     }
 157
 158   printf_filtered ("type = ");
 159
 160   if (real_type)
 161     {
 162       printf_filtered ("/* real type = ");
 163       type_print (real_type, "", gdb_stdout, -1);
 164       if (! full)
 165         printf_filtered (" (incomplete object)");
 166       printf_filtered (" */\n");
 167     }
 168
 169   type_print (type, "", gdb_stdout, show);
 170   printf_filtered ("\n");
 171
 172   if (exp)
 173     do_cleanups (old_chain);
 174 }
 175
 176 static void
 177 whatis_command (char *exp, int from_tty)
 178 {
 179   /* Most of the time users do not want to see all the fields
 180      in a structure.  If they do they can use the "ptype" command.
 181      Hence the "-1" below.  */
 182   whatis_exp (exp, -1);
 183 }
 184
 185 /* Simple subroutine for ptype_command.  */
 186
 187 static struct type *
 188 ptype_eval (struct expression *exp)
 189 {
 190   if (exp->elts[0].opcode == OP_TYPE)
 191     {
 192       return (exp->elts[1].type);
 193     }
 194   else
 195     {
 196       return (NULL);
 197     }
 198 }
 199
 200 /* TYPENAME is either the name of a type, or an expression.  */
 201
 202 static void
 203 ptype_command (char *typename, int from_tty)
 204 {
 205   struct type *type;
 206   struct expression *expr;
 207   struct cleanup *old_chain;
 208
 209   if (typename == NULL)
 210     {
 211       /* Print type of last thing in value history. */
 212       whatis_exp (typename, 1);
 213     }
 214   else
 215     {
 216       expr = parse_expression (typename);
 217       old_chain = make_cleanup (free_current_contents, &expr);
 218       type = ptype_eval (expr);
 219       if (type != NULL)
 220         {
 221           /* User did "ptype <typename>" */
 222           printf_filtered ("type = ");
 223           type_print (type, "", gdb_stdout, 1);
 224           printf_filtered ("\n");
 225           do_cleanups (old_chain);
 226         }
 227       else
 228         {
 229           /* User did "ptype <symbolname>" */
 230           do_cleanups (old_chain);
 231           whatis_exp (typename, 1);
 232         }
 233     }
 234 }
 235
 236 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 237    Used to print data from type structures in a specified type.  For example,
 238    array bounds may be characters or booleans in some languages, and this
 239    allows the ranges to be printed in their "natural" form rather than as
 240    decimal integer values.
 241
 242    FIXME:  This is here simply because only the type printing routines
 243    currently use it, and it wasn't clear if it really belonged somewhere
 244    else (like printcmd.c).  There are a lot of other gdb routines that do
 245    something similar, but they are generally concerned with printing values
 246    that come from the inferior in target byte order and target size. */
 247
 248 void
 249 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 250 {
 251   unsigned int i;
 252   unsigned len;
 253
 254   CHECK_TYPEDEF (type);
 255
 256   switch (TYPE_CODE (type))
 257     {
 258
 259     case TYPE_CODE_ENUM:
 260       len = TYPE_NFIELDS (type);
 261       for (i = 0; i < len; i++)
 262         {
 263           if (TYPE_FIELD_BITPOS (type, i) == val)
 264             {
 265               break;
 266             }
 267         }
 268       if (i < len)
 269         {
 270           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 271         }
 272       else
 273         {
 274           print_longest (stream, 'd', 0, val);
 275         }
 276       break;
 277
 278     case TYPE_CODE_INT:
 279       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 280       break;
 281
 282     case TYPE_CODE_CHAR:
 283       LA_PRINT_CHAR ((unsigned char) val, stream);
 284       break;
 285
 286     case TYPE_CODE_BOOL:
 287       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 288       break;
 289
 290     case TYPE_CODE_RANGE:
 291       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 292       return;
 293
 294     case TYPE_CODE_UNDEF:
 295     case TYPE_CODE_PTR:
 296     case TYPE_CODE_ARRAY:
 297     case TYPE_CODE_STRUCT:
 298     case TYPE_CODE_UNION:
 299     case TYPE_CODE_FUNC:
 300     case TYPE_CODE_FLT:
 301     case TYPE_CODE_VOID:
 302     case TYPE_CODE_SET:
 303     case TYPE_CODE_STRING:
 304     case TYPE_CODE_ERROR:
 305     case TYPE_CODE_MEMBER:
 306     case TYPE_CODE_METHOD:
 307     case TYPE_CODE_REF:
 308     case TYPE_CODE_NAMESPACE:
 309       error ("internal error: unhandled type in print_type_scalar");
 310       break;
 311
 312     default:
 313       error ("Invalid type code in symbol table.");
 314     }
 315   gdb_flush (stream);
 316 }
 317
 318 /* Dump details of a type specified either directly or indirectly.
 319    Uses the same sort of type lookup mechanism as ptype_command()
 320    and whatis_command(). */
 321
 322 void
 323 maintenance_print_type (char *typename, int from_tty)
 324 {
 325   struct value *val;
 326   struct type *type;
 327   struct cleanup *old_chain;
 328   struct expression *expr;
 329
 330   if (typename != NULL)
 331     {
 332       expr = parse_expression (typename);
 333       old_chain = make_cleanup (free_current_contents, &expr);
 334       if (expr->elts[0].opcode == OP_TYPE)
 335         {
 336           /* The user expression names a type directly, just use that type. */
 337           type = expr->elts[1].type;
 338         }
 339       else
 340         {
 341           /* The user expression may name a type indirectly by naming an
 342              object of that type.  Find that indirectly named type. */
 343           val = evaluate_type (expr);
 344           type = VALUE_TYPE (val);
 345         }
 346       if (type != NULL)
 347         {
 348           recursive_dump_type (type, 0);
 349         }
 350       do_cleanups (old_chain);
 351     }
 352 }
 353 \f
 354
 355 void
 356 _initialize_typeprint (void)
 357 {
 358
 359   add_com ("ptype", class_vars, ptype_command,
 360            "Print definition of type TYPE.\n\
 361 Argument may be a type name defined by typedef, or \"struct STRUCT-TAG\"\n\
 362 or \"class CLASS-NAME\" or \"union UNION-TAG\" or \"enum ENUM-TAG\".\n\
 363 The selected stack frame's lexical context is used to look up the name.");
 364
 365   add_com ("whatis", class_vars, whatis_command,
 366            "Print data type of expression EXP.");
 367
 368 }