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 "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 #ifdef _LANG_chill
  92     case language_chill:
  93       fprintf_filtered (stream, "SYNMODE ");
  94       if (!TYPE_NAME (SYMBOL_TYPE (new)) ||
  95           !STREQ (TYPE_NAME (SYMBOL_TYPE (new)), SYMBOL_NAME (new)))
  96         fprintf_filtered (stream, "%s = ", SYMBOL_SOURCE_NAME (new));
  97       else
  98         fprintf_filtered (stream, "<builtin> = ");
  99       type_print (type, "", stream, 0);
 100       break;
 101 #endif
 102     default:
 103       error ("Language not supported.");
 104     }
 105   fprintf_filtered (stream, ";\n");
 106 }
 107
 108 /* Print a description of a type TYPE in the form of a declaration of a
 109    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
 110    Output goes to STREAM (via stdio).
 111    If SHOW is positive, we show the contents of the outermost level
 112    of structure even if there is a type name that could be used instead.
 113    If SHOW is negative, we never show the details of elements' types.  */
 114
 115 void
 116 type_print (struct type *type, char *varstring, struct ui_file *stream,
 117             int show)
 118 {
 119   LA_PRINT_TYPE (type, varstring, stream, show, 0);
 120 }
 121
 122 /* Print type of EXP, or last thing in value history if EXP == NULL.
 123    show is passed to type_print.  */
 124
 125 static void
 126 whatis_exp (char *exp, int show)
 127 {
 128   struct expression *expr;
 129   struct value *val;
 130   register struct cleanup *old_chain = NULL;
 131   struct type *real_type = NULL;
 132   struct type *type;
 133   int full = 0;
 134   int top = -1;
 135   int using_enc = 0;
 136
 137   if (exp)
 138     {
 139       expr = parse_expression (exp);
 140       old_chain = make_cleanup (free_current_contents, &expr);
 141       val = evaluate_type (expr);
 142     }
 143   else
 144     val = access_value_history (0);
 145
 146   type = VALUE_TYPE (val);
 147
 148   if (objectprint)
 149     {
 150       if (((TYPE_CODE (type) == TYPE_CODE_PTR) ||
 151            (TYPE_CODE (type) == TYPE_CODE_REF))
 152           &&
 153           (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 154         {
 155           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 156           if (real_type)
 157             {
 158               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 159                 real_type = lookup_pointer_type (real_type);
 160               else
 161                 real_type = lookup_reference_type (real_type);
 162             }
 163         }
 164       else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
 165   real_type = value_rtti_type (val, &full, &top, &using_enc);
 166     }
 167
 168   printf_filtered ("type = ");
 169
 170   if (real_type)
 171     {
 172       printf_filtered ("/* real type = ");
 173       type_print (real_type, "", gdb_stdout, -1);
 174       if (! full)
 175         printf_filtered (" (incomplete object)");
 176       printf_filtered (" */\n");
 177     }
 178
 179   type_print (type, "", gdb_stdout, show);
 180   printf_filtered ("\n");
 181
 182   if (exp)
 183     do_cleanups (old_chain);
 184 }
 185
 186 /* ARGSUSED */
 187 static void
 188 whatis_command (char *exp, int from_tty)
 189 {
 190   /* Most of the time users do not want to see all the fields
 191      in a structure.  If they do they can use the "ptype" command.
 192      Hence the "-1" below.  */
 193   whatis_exp (exp, -1);
 194 }
 195
 196 /* Simple subroutine for ptype_command.  */
 197
 198 static struct type *
 199 ptype_eval (struct expression *exp)
 200 {
 201   if (exp->elts[0].opcode == OP_TYPE)
 202     {
 203       return (exp->elts[1].type);
 204     }
 205   else
 206     {
 207       return (NULL);
 208     }
 209 }
 210
 211 /* TYPENAME is either the name of a type, or an expression.  */
 212
 213 /* ARGSUSED */
 214 static void
 215 ptype_command (char *typename, int from_tty)
 216 {
 217   register struct type *type;
 218   struct expression *expr;
 219   register struct cleanup *old_chain;
 220
 221   if (typename == NULL)
 222     {
 223       /* Print type of last thing in value history. */
 224       whatis_exp (typename, 1);
 225     }
 226   else
 227     {
 228       expr = parse_expression (typename);
 229       old_chain = make_cleanup (free_current_contents, &expr);
 230       type = ptype_eval (expr);
 231       if (type != NULL)
 232         {
 233           /* User did "ptype <typename>" */
 234           printf_filtered ("type = ");
 235           type_print (type, "", gdb_stdout, 1);
 236           printf_filtered ("\n");
 237           do_cleanups (old_chain);
 238         }
 239       else
 240         {
 241           /* User did "ptype <symbolname>" */
 242           do_cleanups (old_chain);
 243           whatis_exp (typename, 1);
 244         }
 245     }
 246 }
 247
 248 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 249    Used to print data from type structures in a specified type.  For example,
 250    array bounds may be characters or booleans in some languages, and this
 251    allows the ranges to be printed in their "natural" form rather than as
 252    decimal integer values.
 253
 254    FIXME:  This is here simply because only the type printing routines
 255    currently use it, and it wasn't clear if it really belonged somewhere
 256    else (like printcmd.c).  There are a lot of other gdb routines that do
 257    something similar, but they are generally concerned with printing values
 258    that come from the inferior in target byte order and target size. */
 259
 260 void
 261 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 262 {
 263   unsigned int i;
 264   unsigned len;
 265
 266   CHECK_TYPEDEF (type);
 267
 268   switch (TYPE_CODE (type))
 269     {
 270
 271     case TYPE_CODE_ENUM:
 272       len = TYPE_NFIELDS (type);
 273       for (i = 0; i < len; i++)
 274         {
 275           if (TYPE_FIELD_BITPOS (type, i) == val)
 276             {
 277               break;
 278             }
 279         }
 280       if (i < len)
 281         {
 282           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 283         }
 284       else
 285         {
 286           print_longest (stream, 'd', 0, val);
 287         }
 288       break;
 289
 290     case TYPE_CODE_INT:
 291       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 292       break;
 293
 294     case TYPE_CODE_CHAR:
 295       LA_PRINT_CHAR ((unsigned char) val, stream);
 296       break;
 297
 298     case TYPE_CODE_BOOL:
 299       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 300       break;
 301
 302     case TYPE_CODE_RANGE:
 303       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 304       return;
 305
 306     case TYPE_CODE_UNDEF:
 307     case TYPE_CODE_PTR:
 308     case TYPE_CODE_ARRAY:
 309     case TYPE_CODE_STRUCT:
 310     case TYPE_CODE_UNION:
 311     case TYPE_CODE_FUNC:
 312     case TYPE_CODE_FLT:
 313     case TYPE_CODE_VOID:
 314     case TYPE_CODE_SET:
 315     case TYPE_CODE_STRING:
 316     case TYPE_CODE_ERROR:
 317     case TYPE_CODE_MEMBER:
 318     case TYPE_CODE_METHOD:
 319     case TYPE_CODE_REF:
 320       error ("internal error: unhandled type in print_type_scalar");
 321       break;
 322
 323     default:
 324       error ("Invalid type code in symbol table.");
 325     }
 326   gdb_flush (stream);
 327 }
 328
 329 /* Dump details of a type specified either directly or indirectly.
 330    Uses the same sort of type lookup mechanism as ptype_command()
 331    and whatis_command(). */
 332
 333 void
 334 maintenance_print_type (char *typename, int from_tty)
 335 {
 336   struct value *val;
 337   register struct type *type;
 338   register struct cleanup *old_chain;
 339   struct expression *expr;
 340
 341   if (typename != NULL)
 342     {
 343       expr = parse_expression (typename);
 344       old_chain = make_cleanup (free_current_contents, &expr);
 345       if (expr->elts[0].opcode == OP_TYPE)
 346         {
 347           /* The user expression names a type directly, just use that type. */
 348           type = expr->elts[1].type;
 349         }
 350       else
 351         {
 352           /* The user expression may name a type indirectly by naming an
 353              object of that type.  Find that indirectly named type. */
 354           val = evaluate_type (expr);
 355           type = VALUE_TYPE (val);
 356         }
 357       if (type != NULL)
 358         {
 359           recursive_dump_type (type, 0);
 360         }
 361       do_cleanups (old_chain);
 362     }
 363 }
 364 \f
 365
 366 void
 367 _initialize_typeprint (void)
 368 {
 369
 370   add_com ("ptype", class_vars, ptype_command,
 371            "Print definition of type TYPE.\n\
 372 Argument may be a type name defined by typedef, or \"struct STRUCT-TAG\"\n\
 373 or \"class CLASS-NAME\" or \"union UNION-TAG\" or \"enum ENUM-TAG\".\n\
 374 The selected stack frame's lexical context is used to look up the name.");
 375
 376   add_com ("whatis", class_vars, whatis_command,
 377            "Print data type of expression EXP.");
 378
 379 }