gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986, 1988-1989, 1991-1995, 1998-2001, 2003, 2006-2012
   4    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 "exceptions.h"
  37 #include "valprint.h"
  38 #include <errno.h>
  39
  40 extern void _initialize_typeprint (void);
  41
  42 static void ptype_command (char *, int);
  43
  44 static void whatis_command (char *, int);
  45
  46 static void whatis_exp (char *, int);
  47
  48
  49 /* Print a description of a type in the format of a
  50    typedef for the current language.
  51    NEW is the new name for a type TYPE.  */
  52
  53 void
  54 typedef_print (struct type *type, struct symbol *new, struct ui_file *stream)
  55 {
  56   LA_PRINT_TYPEDEF (type, new, stream);
  57 }
  58
  59 /* The default way to print a typedef.  */
  60
  61 void
  62 default_print_typedef (struct type *type, struct symbol *new_symbol,
  63                        struct ui_file *stream)
  64 {
  65   error (_("Language not supported."));
  66 }
  67
  68 /* Print a description of a type TYPE in the form of a declaration of a
  69    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
  70    Output goes to STREAM (via stdio).
  71    If SHOW is positive, we show the contents of the outermost level
  72    of structure even if there is a type name that could be used instead.
  73    If SHOW is negative, we never show the details of elements' types.  */
  74
  75 void
  76 type_print (struct type *type, const char *varstring, struct ui_file *stream,
  77             int show)
  78 {
  79   LA_PRINT_TYPE (type, varstring, stream, show, 0);
  80 }
  81
  82 /* Print TYPE to a string, returning it.  The caller is responsible for
  83    freeing the string.  */
  84
  85 char *
  86 type_to_string (struct type *type)
  87 {
  88   char *s = NULL;
  89   struct ui_file *stb;
  90   struct cleanup *old_chain;
  91   volatile struct gdb_exception except;
  92
  93   stb = mem_fileopen ();
  94   old_chain = make_cleanup_ui_file_delete (stb);
  95
  96   TRY_CATCH (except, RETURN_MASK_ALL)
  97     {
  98       type_print (type, "", stb, -1);
  99       s = ui_file_xstrdup (stb, NULL);
 100     }
 101   if (except.reason < 0)
 102     s = NULL;
 103
 104   do_cleanups (old_chain);
 105
 106   return s;
 107 }
 108
 109 /* Print type of EXP, or last thing in value history if EXP == NULL.
 110    show is passed to type_print.  */
 111
 112 static void
 113 whatis_exp (char *exp, int show)
 114 {
 115   struct expression *expr;
 116   struct value *val;
 117   struct cleanup *old_chain = NULL;
 118   struct type *real_type = NULL;
 119   struct type *type;
 120   int full = 0;
 121   int top = -1;
 122   int using_enc = 0;
 123   struct value_print_options opts;
 124
 125   if (exp)
 126     {
 127       expr = parse_expression (exp);
 128       old_chain = make_cleanup (free_current_contents, &expr);
 129       val = evaluate_type (expr);
 130     }
 131   else
 132     val = access_value_history (0);
 133
 134   type = value_type (val);
 135
 136   get_user_print_options (&opts);
 137   if (opts.objectprint)
 138     {
 139       if (((TYPE_CODE (type) == TYPE_CODE_PTR)
 140            || (TYPE_CODE (type) == TYPE_CODE_REF))
 141           && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 142         {
 143           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 144           if (real_type)
 145             {
 146               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 147                 real_type = lookup_pointer_type (real_type);
 148               else
 149                 real_type = lookup_reference_type (real_type);
 150             }
 151         }
 152       else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
 153         real_type = value_rtti_type (val, &full, &top, &using_enc);
 154     }
 155
 156   printf_filtered ("type = ");
 157
 158   if (real_type)
 159     {
 160       printf_filtered ("/* real type = ");
 161       type_print (real_type, "", gdb_stdout, -1);
 162       if (! full)
 163         printf_filtered (" (incomplete object)");
 164       printf_filtered (" */\n");
 165     }
 166
 167   type_print (type, "", gdb_stdout, show);
 168   printf_filtered ("\n");
 169
 170   if (exp)
 171     do_cleanups (old_chain);
 172 }
 173
 174 static void
 175 whatis_command (char *exp, int from_tty)
 176 {
 177   /* Most of the time users do not want to see all the fields
 178      in a structure.  If they do they can use the "ptype" command.
 179      Hence the "-1" below.  */
 180   whatis_exp (exp, -1);
 181 }
 182
 183 /* TYPENAME is either the name of a type, or an expression.  */
 184
 185 static void
 186 ptype_command (char *typename, int from_tty)
 187 {
 188   whatis_exp (typename, 1);
 189 }
 190
 191 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 192    Used to print data from type structures in a specified type.  For example,
 193    array bounds may be characters or booleans in some languages, and this
 194    allows the ranges to be printed in their "natural" form rather than as
 195    decimal integer values.
 196
 197    FIXME:  This is here simply because only the type printing routines
 198    currently use it, and it wasn't clear if it really belonged somewhere
 199    else (like printcmd.c).  There are a lot of other gdb routines that do
 200    something similar, but they are generally concerned with printing values
 201    that come from the inferior in target byte order and target size.  */
 202
 203 void
 204 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 205 {
 206   unsigned int i;
 207   unsigned len;
 208
 209   CHECK_TYPEDEF (type);
 210
 211   switch (TYPE_CODE (type))
 212     {
 213
 214     case TYPE_CODE_ENUM:
 215       len = TYPE_NFIELDS (type);
 216       for (i = 0; i < len; i++)
 217         {
 218           if (TYPE_FIELD_BITPOS (type, i) == val)
 219             {
 220               break;
 221             }
 222         }
 223       if (i < len)
 224         {
 225           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 226         }
 227       else
 228         {
 229           print_longest (stream, 'd', 0, val);
 230         }
 231       break;
 232
 233     case TYPE_CODE_INT:
 234       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 235       break;
 236
 237     case TYPE_CODE_CHAR:
 238       LA_PRINT_CHAR ((unsigned char) val, type, stream);
 239       break;
 240
 241     case TYPE_CODE_BOOL:
 242       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 243       break;
 244
 245     case TYPE_CODE_RANGE:
 246       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 247       return;
 248
 249     case TYPE_CODE_UNDEF:
 250     case TYPE_CODE_PTR:
 251     case TYPE_CODE_ARRAY:
 252     case TYPE_CODE_STRUCT:
 253     case TYPE_CODE_UNION:
 254     case TYPE_CODE_FUNC:
 255     case TYPE_CODE_FLT:
 256     case TYPE_CODE_VOID:
 257     case TYPE_CODE_SET:
 258     case TYPE_CODE_STRING:
 259     case TYPE_CODE_ERROR:
 260     case TYPE_CODE_MEMBERPTR:
 261     case TYPE_CODE_METHODPTR:
 262     case TYPE_CODE_METHOD:
 263     case TYPE_CODE_REF:
 264     case TYPE_CODE_NAMESPACE:
 265       error (_("internal error: unhandled type in print_type_scalar"));
 266       break;
 267
 268     default:
 269       error (_("Invalid type code in symbol table."));
 270     }
 271   gdb_flush (stream);
 272 }
 273
 274 /* Dump details of a type specified either directly or indirectly.
 275    Uses the same sort of type lookup mechanism as ptype_command()
 276    and whatis_command().  */
 277
 278 void
 279 maintenance_print_type (char *typename, int from_tty)
 280 {
 281   struct value *val;
 282   struct type *type;
 283   struct cleanup *old_chain;
 284   struct expression *expr;
 285
 286   if (typename != NULL)
 287     {
 288       expr = parse_expression (typename);
 289       old_chain = make_cleanup (free_current_contents, &expr);
 290       if (expr->elts[0].opcode == OP_TYPE)
 291         {
 292           /* The user expression names a type directly, just use that type.  */
 293           type = expr->elts[1].type;
 294         }
 295       else
 296         {
 297           /* The user expression may name a type indirectly by naming an
 298              object of that type.  Find that indirectly named type.  */
 299           val = evaluate_type (expr);
 300           type = value_type (val);
 301         }
 302       if (type != NULL)
 303         {
 304           recursive_dump_type (type, 0);
 305         }
 306       do_cleanups (old_chain);
 307     }
 308 }
 309 \f
 310
 311 void
 312 _initialize_typeprint (void)
 313 {
 314   add_com ("ptype", class_vars, ptype_command, _("\
 315 Print definition of type TYPE.\n\
 316 Argument may be a type name defined by typedef, or \"struct STRUCT-TAG\"\n\
 317 or \"class CLASS-NAME\" or \"union UNION-TAG\" or \"enum ENUM-TAG\".\n\
 318 The selected stack frame's lexical context is used to look up the name.\n\
 319 Contrary to \"whatis\", \"ptype\" always unrolls any typedefs."));
 320
 321   add_com ("whatis", class_vars, whatis_command,
 322            _("Print data type of expression EXP.\n\
 323 Only one level of typedefs is unrolled.  See also \"ptype\"."));
 324 }