gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1998, 1999,
   4    2000, 2001, 2003, 2006, 2007 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 3 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, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdb_obstack.h"
  23 #include "bfd.h"                /* Binary File Description */
  24 #include "symtab.h"
  25 #include "gdbtypes.h"
  26 #include "expression.h"
  27 #include "value.h"
  28 #include "gdbcore.h"
  29 #include "command.h"
  30 #include "gdbcmd.h"
  31 #include "target.h"
  32 #include "language.h"
  33 #include "cp-abi.h"
  34 #include "typeprint.h"
  35 #include "gdb_string.h"
  36 #include <errno.h>
  37
  38 /* For real-type printing in whatis_exp() */
  39 extern int objectprint;         /* Controls looking up an object's derived type
  40                                    using what we find in its vtables.  */
  41
  42 extern void _initialize_typeprint (void);
  43
  44 static void ptype_command (char *, int);
  45
  46 static void whatis_command (char *, int);
  47
  48 static void whatis_exp (char *, int);
  49
  50 /* Print a description of a type in the format of a
  51    typedef for the current language.
  52    NEW is the new name for a type TYPE. */
  53
  54 void
  55 typedef_print (struct type *type, struct symbol *new, struct ui_file *stream)
  56 {
  57   CHECK_TYPEDEF (type);
  58   switch (current_language->la_language)
  59     {
  60 #ifdef _LANG_c
  61     case language_c:
  62     case language_cplus:
  63       fprintf_filtered (stream, "typedef ");
  64       type_print (type, "", stream, 0);
  65       if (TYPE_NAME ((SYMBOL_TYPE (new))) == 0
  66           || strcmp (TYPE_NAME ((SYMBOL_TYPE (new))), DEPRECATED_SYMBOL_NAME (new)) != 0)
  67         fprintf_filtered (stream, " %s", SYMBOL_PRINT_NAME (new));
  68       break;
  69 #endif
  70 #ifdef _LANG_m2
  71     case language_m2:
  72       fprintf_filtered (stream, "TYPE ");
  73       if (!TYPE_NAME (SYMBOL_TYPE (new))
  74           || strcmp (TYPE_NAME ((SYMBOL_TYPE (new))), DEPRECATED_SYMBOL_NAME (new)) != 0)
  75         fprintf_filtered (stream, "%s = ", SYMBOL_PRINT_NAME (new));
  76       else
  77         fprintf_filtered (stream, "<builtin> = ");
  78       type_print (type, "", stream, 0);
  79       break;
  80 #endif
  81 #ifdef _LANG_pascal
  82     case language_pascal:
  83       fprintf_filtered (stream, "type ");
  84       fprintf_filtered (stream, "%s = ", SYMBOL_PRINT_NAME (new));
  85       type_print (type, "", stream, 0);
  86       break;
  87 #endif
  88     default:
  89       error (_("Language not supported."));
  90     }
  91   fprintf_filtered (stream, ";\n");
  92 }
  93
  94 /* Print a description of a type TYPE in the form of a declaration of a
  95    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
  96    Output goes to STREAM (via stdio).
  97    If SHOW is positive, we show the contents of the outermost level
  98    of structure even if there is a type name that could be used instead.
  99    If SHOW is negative, we never show the details of elements' types.  */
 100
 101 void
 102 type_print (struct type *type, char *varstring, struct ui_file *stream,
 103             int show)
 104 {
 105   LA_PRINT_TYPE (type, varstring, stream, show, 0);
 106 }
 107
 108 /* Print type of EXP, or last thing in value history if EXP == NULL.
 109    show is passed to type_print.  */
 110
 111 static void
 112 whatis_exp (char *exp, int show)
 113 {
 114   struct expression *expr;
 115   struct value *val;
 116   struct cleanup *old_chain = NULL;
 117   struct type *real_type = NULL;
 118   struct type *type;
 119   int full = 0;
 120   int top = -1;
 121   int using_enc = 0;
 122
 123   if (exp)
 124     {
 125       expr = parse_expression (exp);
 126       old_chain = make_cleanup (free_current_contents, &expr);
 127       val = evaluate_type (expr);
 128     }
 129   else
 130     val = access_value_history (0);
 131
 132   type = value_type (val);
 133
 134   if (objectprint)
 135     {
 136       if (((TYPE_CODE (type) == TYPE_CODE_PTR) ||
 137            (TYPE_CODE (type) == TYPE_CODE_REF))
 138           &&
 139           (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 140         {
 141           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 142           if (real_type)
 143             {
 144               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 145                 real_type = lookup_pointer_type (real_type);
 146               else
 147                 real_type = lookup_reference_type (real_type);
 148             }
 149         }
 150       else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
 151   real_type = value_rtti_type (val, &full, &top, &using_enc);
 152     }
 153
 154   printf_filtered ("type = ");
 155
 156   if (real_type)
 157     {
 158       printf_filtered ("/* real type = ");
 159       type_print (real_type, "", gdb_stdout, -1);
 160       if (! full)
 161         printf_filtered (" (incomplete object)");
 162       printf_filtered (" */\n");
 163     }
 164
 165   type_print (type, "", gdb_stdout, show);
 166   printf_filtered ("\n");
 167
 168   if (exp)
 169     do_cleanups (old_chain);
 170 }
 171
 172 static void
 173 whatis_command (char *exp, int from_tty)
 174 {
 175   /* Most of the time users do not want to see all the fields
 176      in a structure.  If they do they can use the "ptype" command.
 177      Hence the "-1" below.  */
 178   whatis_exp (exp, -1);
 179 }
 180
 181 /* TYPENAME is either the name of a type, or an expression.  */
 182
 183 static void
 184 ptype_command (char *typename, int from_tty)
 185 {
 186   whatis_exp (typename, 1);
 187 }
 188
 189 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 190    Used to print data from type structures in a specified type.  For example,
 191    array bounds may be characters or booleans in some languages, and this
 192    allows the ranges to be printed in their "natural" form rather than as
 193    decimal integer values.
 194
 195    FIXME:  This is here simply because only the type printing routines
 196    currently use it, and it wasn't clear if it really belonged somewhere
 197    else (like printcmd.c).  There are a lot of other gdb routines that do
 198    something similar, but they are generally concerned with printing values
 199    that come from the inferior in target byte order and target size. */
 200
 201 void
 202 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 203 {
 204   unsigned int i;
 205   unsigned len;
 206
 207   CHECK_TYPEDEF (type);
 208
 209   switch (TYPE_CODE (type))
 210     {
 211
 212     case TYPE_CODE_ENUM:
 213       len = TYPE_NFIELDS (type);
 214       for (i = 0; i < len; i++)
 215         {
 216           if (TYPE_FIELD_BITPOS (type, i) == val)
 217             {
 218               break;
 219             }
 220         }
 221       if (i < len)
 222         {
 223           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 224         }
 225       else
 226         {
 227           print_longest (stream, 'd', 0, val);
 228         }
 229       break;
 230
 231     case TYPE_CODE_INT:
 232       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 233       break;
 234
 235     case TYPE_CODE_CHAR:
 236       LA_PRINT_CHAR ((unsigned char) val, stream);
 237       break;
 238
 239     case TYPE_CODE_BOOL:
 240       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 241       break;
 242
 243     case TYPE_CODE_RANGE:
 244       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 245       return;
 246
 247     case TYPE_CODE_UNDEF:
 248     case TYPE_CODE_PTR:
 249     case TYPE_CODE_ARRAY:
 250     case TYPE_CODE_STRUCT:
 251     case TYPE_CODE_UNION:
 252     case TYPE_CODE_FUNC:
 253     case TYPE_CODE_FLT:
 254     case TYPE_CODE_VOID:
 255     case TYPE_CODE_SET:
 256     case TYPE_CODE_STRING:
 257     case TYPE_CODE_ERROR:
 258     case TYPE_CODE_MEMBERPTR:
 259     case TYPE_CODE_METHODPTR:
 260     case TYPE_CODE_METHOD:
 261     case TYPE_CODE_REF:
 262     case TYPE_CODE_NAMESPACE:
 263       error (_("internal error: unhandled type in print_type_scalar"));
 264       break;
 265
 266     default:
 267       error (_("Invalid type code in symbol table."));
 268     }
 269   gdb_flush (stream);
 270 }
 271
 272 /* Dump details of a type specified either directly or indirectly.
 273    Uses the same sort of type lookup mechanism as ptype_command()
 274    and whatis_command(). */
 275
 276 void
 277 maintenance_print_type (char *typename, int from_tty)
 278 {
 279   struct value *val;
 280   struct type *type;
 281   struct cleanup *old_chain;
 282   struct expression *expr;
 283
 284   if (typename != NULL)
 285     {
 286       expr = parse_expression (typename);
 287       old_chain = make_cleanup (free_current_contents, &expr);
 288       if (expr->elts[0].opcode == OP_TYPE)
 289         {
 290           /* The user expression names a type directly, just use that type. */
 291           type = expr->elts[1].type;
 292         }
 293       else
 294         {
 295           /* The user expression may name a type indirectly by naming an
 296              object of that type.  Find that indirectly named type. */
 297           val = evaluate_type (expr);
 298           type = value_type (val);
 299         }
 300       if (type != NULL)
 301         {
 302           recursive_dump_type (type, 0);
 303         }
 304       do_cleanups (old_chain);
 305     }
 306 }
 307 \f
 308
 309 void
 310 _initialize_typeprint (void)
 311 {
 312
 313   add_com ("ptype", class_vars, ptype_command, _("\
 314 Print definition of type TYPE.\n\
 315 Argument may be a type name defined by typedef, or \"struct STRUCT-TAG\"\n\
 316 or \"class CLASS-NAME\" or \"union UNION-TAG\" or \"enum ENUM-TAG\".\n\
 317 The selected stack frame's lexical context is used to look up the name."));
 318
 319   add_com ("whatis", class_vars, whatis_command,
 320            _("Print data type of expression EXP."));
 321
 322 }