gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2    Copyright 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1998, 1999,
   3    2000, 2001 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 "gdb_obstack.h"
  24 #include "bfd.h"                /* Binary File Description */
  25 #include "symtab.h"
  26 #include "gdbtypes.h"
  27 #include "expression.h"
  28 #include "value.h"
  29 #include "gdbcore.h"
  30 #include "command.h"
  31 #include "gdbcmd.h"
  32 #include "target.h"
  33 #include "language.h"
  34 #include "cp-abi.h"
  35
  36 #include "gdb_string.h"
  37 #include <errno.h>
  38
  39 /* For real-type printing in whatis_exp() */
  40 extern int objectprint;         /* Controls looking up an object's derived type
  41                                    using what we find in its vtables.  */
  42
  43 extern void _initialize_typeprint (void);
  44
  45 static void ptype_command (char *, int);
  46
  47 static struct type *ptype_eval (struct expression *);
  48
  49 static void whatis_command (char *, int);
  50
  51 static void whatis_exp (char *, int);
  52
  53 /* Print a description of a type in the format of a
  54    typedef for the current language.
  55    NEW is the new name for a type TYPE. */
  56
  57 void
  58 typedef_print (struct type *type, struct symbol *new, struct ui_file *stream)
  59 {
  60   CHECK_TYPEDEF (type);
  61   switch (current_language->la_language)
  62     {
  63 #ifdef _LANG_c
  64     case language_c:
  65     case language_cplus:
  66       fprintf_filtered (stream, "typedef ");
  67       type_print (type, "", stream, 0);
  68       if (TYPE_NAME ((SYMBOL_TYPE (new))) == 0
  69           || !STREQ (TYPE_NAME ((SYMBOL_TYPE (new))), SYMBOL_NAME (new)))
  70         fprintf_filtered (stream, " %s", SYMBOL_SOURCE_NAME (new));
  71       break;
  72 #endif
  73 #ifdef _LANG_m2
  74     case language_m2:
  75       fprintf_filtered (stream, "TYPE ");
  76       if (!TYPE_NAME (SYMBOL_TYPE (new)) ||
  77           !STREQ (TYPE_NAME (SYMBOL_TYPE (new)), SYMBOL_NAME (new)))
  78         fprintf_filtered (stream, "%s = ", SYMBOL_SOURCE_NAME (new));
  79       else
  80         fprintf_filtered (stream, "<builtin> = ");
  81       type_print (type, "", stream, 0);
  82       break;
  83 #endif
  84 #ifdef _LANG_pascal
  85     case language_pascal:
  86       fprintf_filtered (stream, "type ");
  87       fprintf_filtered (stream, "%s = ", SYMBOL_SOURCE_NAME (new));
  88       type_print (type, "", stream, 0);
  89       break;
  90 #endif
  91     default:
  92       error ("Language not supported.");
  93     }
  94   fprintf_filtered (stream, ";\n");
  95 }
  96
  97 /* Print a description of a type TYPE in the form of a declaration of a
  98    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
  99    Output goes to STREAM (via stdio).
 100    If SHOW is positive, we show the contents of the outermost level
 101    of structure even if there is a type name that could be used instead.
 102    If SHOW is negative, we never show the details of elements' types.  */
 103
 104 void
 105 type_print (struct type *type, char *varstring, struct ui_file *stream,
 106             int show)
 107 {
 108   LA_PRINT_TYPE (type, varstring, stream, show, 0);
 109 }
 110
 111 /* Print type of EXP, or last thing in value history if EXP == NULL.
 112    show is passed to type_print.  */
 113
 114 static void
 115 whatis_exp (char *exp, int show)
 116 {
 117   struct expression *expr;
 118   struct value *val;
 119   register struct cleanup *old_chain = NULL;
 120   struct type *real_type = NULL;
 121   struct type *type;
 122   int full = 0;
 123   int top = -1;
 124   int using_enc = 0;
 125
 126   if (exp)
 127     {
 128       expr = parse_expression (exp);
 129       old_chain = make_cleanup (free_current_contents, &expr);
 130       val = evaluate_type (expr);
 131     }
 132   else
 133     val = access_value_history (0);
 134
 135   type = VALUE_TYPE (val);
 136
 137   if (objectprint)
 138     {
 139       if (((TYPE_CODE (type) == TYPE_CODE_PTR) ||
 140            (TYPE_CODE (type) == TYPE_CODE_REF))
 141           &&
 142           (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 143         {
 144           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 145           if (real_type)
 146             {
 147               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 148                 real_type = lookup_pointer_type (real_type);
 149               else
 150                 real_type = lookup_reference_type (real_type);
 151             }
 152         }
 153       else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
 154   real_type = value_rtti_type (val, &full, &top, &using_enc);
 155     }
 156
 157   printf_filtered ("type = ");
 158
 159   if (real_type)
 160     {
 161       printf_filtered ("/* real type = ");
 162       type_print (real_type, "", gdb_stdout, -1);
 163       if (! full)
 164         printf_filtered (" (incomplete object)");
 165       printf_filtered (" */\n");
 166     }
 167
 168   type_print (type, "", gdb_stdout, show);
 169   printf_filtered ("\n");
 170
 171   if (exp)
 172     do_cleanups (old_chain);
 173 }
 174
 175 /* ARGSUSED */
 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 /* ARGSUSED */
 203 static void
 204 ptype_command (char *typename, int from_tty)
 205 {
 206   register struct type *type;
 207   struct expression *expr;
 208   register struct cleanup *old_chain;
 209
 210   if (typename == NULL)
 211     {
 212       /* Print type of last thing in value history. */
 213       whatis_exp (typename, 1);
 214     }
 215   else
 216     {
 217       expr = parse_expression (typename);
 218       old_chain = make_cleanup (free_current_contents, &expr);
 219       type = ptype_eval (expr);
 220       if (type != NULL)
 221         {
 222           /* User did "ptype <typename>" */
 223           printf_filtered ("type = ");
 224           type_print (type, "", gdb_stdout, 1);
 225           printf_filtered ("\n");
 226           do_cleanups (old_chain);
 227         }
 228       else
 229         {
 230           /* User did "ptype <symbolname>" */
 231           do_cleanups (old_chain);
 232           whatis_exp (typename, 1);
 233         }
 234     }
 235 }
 236
 237 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 238    Used to print data from type structures in a specified type.  For example,
 239    array bounds may be characters or booleans in some languages, and this
 240    allows the ranges to be printed in their "natural" form rather than as
 241    decimal integer values.
 242
 243    FIXME:  This is here simply because only the type printing routines
 244    currently use it, and it wasn't clear if it really belonged somewhere
 245    else (like printcmd.c).  There are a lot of other gdb routines that do
 246    something similar, but they are generally concerned with printing values
 247    that come from the inferior in target byte order and target size. */
 248
 249 void
 250 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 251 {
 252   unsigned int i;
 253   unsigned len;
 254
 255   CHECK_TYPEDEF (type);
 256
 257   switch (TYPE_CODE (type))
 258     {
 259
 260     case TYPE_CODE_ENUM:
 261       len = TYPE_NFIELDS (type);
 262       for (i = 0; i < len; i++)
 263         {
 264           if (TYPE_FIELD_BITPOS (type, i) == val)
 265             {
 266               break;
 267             }
 268         }
 269       if (i < len)
 270         {
 271           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 272         }
 273       else
 274         {
 275           print_longest (stream, 'd', 0, val);
 276         }
 277       break;
 278
 279     case TYPE_CODE_INT:
 280       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 281       break;
 282
 283     case TYPE_CODE_CHAR:
 284       LA_PRINT_CHAR ((unsigned char) val, stream);
 285       break;
 286
 287     case TYPE_CODE_BOOL:
 288       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 289       break;
 290
 291     case TYPE_CODE_RANGE:
 292       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 293       return;
 294
 295     case TYPE_CODE_UNDEF:
 296     case TYPE_CODE_PTR:
 297     case TYPE_CODE_ARRAY:
 298     case TYPE_CODE_STRUCT:
 299     case TYPE_CODE_UNION:
 300     case TYPE_CODE_FUNC:
 301     case TYPE_CODE_FLT:
 302     case TYPE_CODE_VOID:
 303     case TYPE_CODE_SET:
 304     case TYPE_CODE_STRING:
 305     case TYPE_CODE_ERROR:
 306     case TYPE_CODE_MEMBER:
 307     case TYPE_CODE_METHOD:
 308     case TYPE_CODE_REF:
 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   register struct type *type;
 327   register 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 }