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, 2008, 2009, 2010, 2011
   5    Free Software Foundation, Inc.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  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 #include "typeprint.h"
  36 #include "gdb_string.h"
  37 #include "exceptions.h"
  38 #include "valprint.h"
  39 #include <errno.h>
  40
  41 extern void _initialize_typeprint (void);
  42
  43 static void ptype_command (char *, int);
  44
  45 static void whatis_command (char *, int);
  46
  47 static void whatis_exp (char *, int);
  48
  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   LA_PRINT_TYPEDEF (type, new, stream);
  58 }
  59
  60 /* The default way to print a typedef.  */
  61
  62 void
  63 default_print_typedef (struct type *type, struct symbol *new_symbol,
  64                        struct ui_file *stream)
  65 {
  66   error (_("Language not supported."));
  67 }
  68
  69 /* Print a description of a type TYPE in the form of a declaration of a
  70    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
  71    Output goes to STREAM (via stdio).
  72    If SHOW is positive, we show the contents of the outermost level
  73    of structure even if there is a type name that could be used instead.
  74    If SHOW is negative, we never show the details of elements' types.  */
  75
  76 void
  77 type_print (struct type *type, char *varstring, struct ui_file *stream,
  78             int show)
  79 {
  80   LA_PRINT_TYPE (type, varstring, stream, show, 0);
  81 }
  82
  83 /* Print TYPE to a string, returning it.  The caller is responsible for
  84    freeing the string.  */
  85
  86 char *
  87 type_to_string (struct type *type)
  88 {
  89   char *s = NULL;
  90   struct ui_file *stb;
  91   struct cleanup *old_chain;
  92   volatile struct gdb_exception except;
  93
  94   stb = mem_fileopen ();
  95   old_chain = make_cleanup_ui_file_delete (stb);
  96
  97   TRY_CATCH (except, RETURN_MASK_ALL)
  98     {
  99       type_print (type, "", stb, -1);
 100       s = ui_file_xstrdup (stb, NULL);
 101     }
 102   if (except.reason < 0)
 103     s = NULL;
 104
 105   do_cleanups (old_chain);
 106
 107   return s;
 108 }
 109
 110 /* Print type of EXP, or last thing in value history if EXP == NULL.
 111    show is passed to type_print.  */
 112
 113 static void
 114 whatis_exp (char *exp, int show)
 115 {
 116   struct expression *expr;
 117   struct value *val;
 118   struct cleanup *old_chain = NULL;
 119   struct type *real_type = NULL;
 120   struct type *type;
 121   int full = 0;
 122   int top = -1;
 123   int using_enc = 0;
 124   struct value_print_options opts;
 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   get_user_print_options (&opts);
 138   if (opts.objectprint)
 139     {
 140       if (((TYPE_CODE (type) == TYPE_CODE_PTR)
 141            || (TYPE_CODE (type) == TYPE_CODE_REF))
 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 static void
 176 whatis_command (char *exp, int from_tty)
 177 {
 178   /* Most of the time users do not want to see all the fields
 179      in a structure.  If they do they can use the "ptype" command.
 180      Hence the "-1" below.  */
 181   whatis_exp (exp, -1);
 182 }
 183
 184 /* TYPENAME is either the name of a type, or an expression.  */
 185
 186 static void
 187 ptype_command (char *typename, int from_tty)
 188 {
 189   whatis_exp (typename, 1);
 190 }
 191
 192 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 193    Used to print data from type structures in a specified type.  For example,
 194    array bounds may be characters or booleans in some languages, and this
 195    allows the ranges to be printed in their "natural" form rather than as
 196    decimal integer values.
 197
 198    FIXME:  This is here simply because only the type printing routines
 199    currently use it, and it wasn't clear if it really belonged somewhere
 200    else (like printcmd.c).  There are a lot of other gdb routines that do
 201    something similar, but they are generally concerned with printing values
 202    that come from the inferior in target byte order and target size.  */
 203
 204 void
 205 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 206 {
 207   unsigned int i;
 208   unsigned len;
 209
 210   CHECK_TYPEDEF (type);
 211
 212   switch (TYPE_CODE (type))
 213     {
 214
 215     case TYPE_CODE_ENUM:
 216       len = TYPE_NFIELDS (type);
 217       for (i = 0; i < len; i++)
 218         {
 219           if (TYPE_FIELD_BITPOS (type, i) == val)
 220             {
 221               break;
 222             }
 223         }
 224       if (i < len)
 225         {
 226           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 227         }
 228       else
 229         {
 230           print_longest (stream, 'd', 0, val);
 231         }
 232       break;
 233
 234     case TYPE_CODE_INT:
 235       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 236       break;
 237
 238     case TYPE_CODE_CHAR:
 239       LA_PRINT_CHAR ((unsigned char) val, type, stream);
 240       break;
 241
 242     case TYPE_CODE_BOOL:
 243       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 244       break;
 245
 246     case TYPE_CODE_RANGE:
 247       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 248       return;
 249
 250     case TYPE_CODE_UNDEF:
 251     case TYPE_CODE_PTR:
 252     case TYPE_CODE_ARRAY:
 253     case TYPE_CODE_STRUCT:
 254     case TYPE_CODE_UNION:
 255     case TYPE_CODE_FUNC:
 256     case TYPE_CODE_FLT:
 257     case TYPE_CODE_VOID:
 258     case TYPE_CODE_SET:
 259     case TYPE_CODE_STRING:
 260     case TYPE_CODE_ERROR:
 261     case TYPE_CODE_MEMBERPTR:
 262     case TYPE_CODE_METHODPTR:
 263     case TYPE_CODE_METHOD:
 264     case TYPE_CODE_REF:
 265     case TYPE_CODE_NAMESPACE:
 266       error (_("internal error: unhandled type in print_type_scalar"));
 267       break;
 268
 269     default:
 270       error (_("Invalid type code in symbol table."));
 271     }
 272   gdb_flush (stream);
 273 }
 274
 275 /* Dump details of a type specified either directly or indirectly.
 276    Uses the same sort of type lookup mechanism as ptype_command()
 277    and whatis_command().  */
 278
 279 void
 280 maintenance_print_type (char *typename, int from_tty)
 281 {
 282   struct value *val;
 283   struct type *type;
 284   struct cleanup *old_chain;
 285   struct expression *expr;
 286
 287   if (typename != NULL)
 288     {
 289       expr = parse_expression (typename);
 290       old_chain = make_cleanup (free_current_contents, &expr);
 291       if (expr->elts[0].opcode == OP_TYPE)
 292         {
 293           /* The user expression names a type directly, just use that type.  */
 294           type = expr->elts[1].type;
 295         }
 296       else
 297         {
 298           /* The user expression may name a type indirectly by naming an
 299              object of that type.  Find that indirectly named type.  */
 300           val = evaluate_type (expr);
 301           type = value_type (val);
 302         }
 303       if (type != NULL)
 304         {
 305           recursive_dump_type (type, 0);
 306         }
 307       do_cleanups (old_chain);
 308     }
 309 }
 310 \f
 311
 312 void
 313 _initialize_typeprint (void)
 314 {
 315   add_com ("ptype", class_vars, ptype_command, _("\
 316 Print definition of type TYPE.\n\
 317 Argument may be a type name defined by typedef, or \"struct STRUCT-TAG\"\n\
 318 or \"class CLASS-NAME\" or \"union UNION-TAG\" or \"enum ENUM-TAG\".\n\
 319 The selected stack frame's lexical context is used to look up the name."));
 320
 321   add_com ("whatis", class_vars, whatis_command,
 322            _("Print data type of expression EXP."));
 323 }