gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2
   3    Copyright 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1998,
   4    1999, 2000, 2001, 2003 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 2 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, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "gdb_obstack.h"
  25 #include "bfd.h"                /* Binary File Description */
  26 #include "symtab.h"
  27 #include "gdbtypes.h"
  28 #include "expression.h"
  29 #include "value.h"
  30 #include "gdbcore.h"
  31 #include "command.h"
  32 #include "gdbcmd.h"
  33 #include "target.h"
  34 #include "language.h"
  35 #include "cp-abi.h"
  36 #include "typeprint.h"
  37 #include "gdb_string.h"
  38 #include <errno.h>
  39
  40 /* For real-type printing in whatis_exp() */
  41 extern int objectprint;         /* Controls looking up an object's derived type
  42                                    using what we find in its vtables.  */
  43
  44 extern void _initialize_typeprint (void);
  45
  46 static void ptype_command (char *, int);
  47
  48 static struct type *ptype_eval (struct expression *);
  49
  50 static void whatis_command (char *, int);
  51
  52 static void whatis_exp (char *, int);
  53
  54 /* Print a description of a type in the format of a
  55    typedef for the current language.
  56    NEW is the new name for a type TYPE. */
  57
  58 void
  59 typedef_print (struct type *type, struct symbol *new, struct ui_file *stream)
  60 {
  61   CHECK_TYPEDEF (type);
  62   switch (current_language->la_language)
  63     {
  64 #ifdef _LANG_c
  65     case language_c:
  66     case language_cplus:
  67       fprintf_filtered (stream, "typedef ");
  68       type_print (type, "", stream, 0);
  69       if (TYPE_NAME ((SYMBOL_TYPE (new))) == 0
  70           || strcmp (TYPE_NAME ((SYMBOL_TYPE (new))), DEPRECATED_SYMBOL_NAME (new)) != 0)
  71         fprintf_filtered (stream, " %s", SYMBOL_PRINT_NAME (new));
  72       break;
  73 #endif
  74 #ifdef _LANG_m2
  75     case language_m2:
  76       fprintf_filtered (stream, "TYPE ");
  77       if (!TYPE_NAME (SYMBOL_TYPE (new))
  78           || strcmp (TYPE_NAME ((SYMBOL_TYPE (new))), DEPRECATED_SYMBOL_NAME (new)) != 0)
  79         fprintf_filtered (stream, "%s = ", SYMBOL_PRINT_NAME (new));
  80       else
  81         fprintf_filtered (stream, "<builtin> = ");
  82       type_print (type, "", stream, 0);
  83       break;
  84 #endif
  85 #ifdef _LANG_pascal
  86     case language_pascal:
  87       fprintf_filtered (stream, "type ");
  88       fprintf_filtered (stream, "%s = ", SYMBOL_PRINT_NAME (new));
  89       type_print (type, "", stream, 0);
  90       break;
  91 #endif
  92     default:
  93       error ("Language not supported.");
  94     }
  95   fprintf_filtered (stream, ";\n");
  96 }
  97
  98 /* Print a description of a type TYPE in the form of a declaration of a
  99    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
 100    Output goes to STREAM (via stdio).
 101    If SHOW is positive, we show the contents of the outermost level
 102    of structure even if there is a type name that could be used instead.
 103    If SHOW is negative, we never show the details of elements' types.  */
 104
 105 void
 106 type_print (struct type *type, char *varstring, struct ui_file *stream,
 107             int show)
 108 {
 109   LA_PRINT_TYPE (type, varstring, stream, show, 0);
 110 }
 111
 112 /* Print type of EXP, or last thing in value history if EXP == NULL.
 113    show is passed to type_print.  */
 114
 115 static void
 116 whatis_exp (char *exp, int show)
 117 {
 118   struct expression *expr;
 119   struct value *val;
 120   register struct cleanup *old_chain = NULL;
 121   struct type *real_type = NULL;
 122   struct type *type;
 123   int full = 0;
 124   int top = -1;
 125   int using_enc = 0;
 126
 127   if (exp)
 128     {
 129       expr = parse_expression (exp);
 130       old_chain = make_cleanup (free_current_contents, &expr);
 131       val = evaluate_type (expr);
 132     }
 133   else
 134     val = access_value_history (0);
 135
 136   type = VALUE_TYPE (val);
 137
 138   if (objectprint)
 139     {
 140       if (((TYPE_CODE (type) == TYPE_CODE_PTR) ||
 141            (TYPE_CODE (type) == TYPE_CODE_REF))
 142           &&
 143           (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
 144         {
 145           real_type = value_rtti_target_type (val, &full, &top, &using_enc);
 146           if (real_type)
 147             {
 148               if (TYPE_CODE (type) == TYPE_CODE_PTR)
 149                 real_type = lookup_pointer_type (real_type);
 150               else
 151                 real_type = lookup_reference_type (real_type);
 152             }
 153         }
 154       else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
 155   real_type = value_rtti_type (val, &full, &top, &using_enc);
 156     }
 157
 158   printf_filtered ("type = ");
 159
 160   if (real_type)
 161     {
 162       printf_filtered ("/* real type = ");
 163       type_print (real_type, "", gdb_stdout, -1);
 164       if (! full)
 165         printf_filtered (" (incomplete object)");
 166       printf_filtered (" */\n");
 167     }
 168
 169   type_print (type, "", gdb_stdout, show);
 170   printf_filtered ("\n");
 171
 172   if (exp)
 173     do_cleanups (old_chain);
 174 }
 175
 176 /* ARGSUSED */
 177 static void
 178 whatis_command (char *exp, int from_tty)
 179 {
 180   /* Most of the time users do not want to see all the fields
 181      in a structure.  If they do they can use the "ptype" command.
 182      Hence the "-1" below.  */
 183   whatis_exp (exp, -1);
 184 }
 185
 186 /* Simple subroutine for ptype_command.  */
 187
 188 static struct type *
 189 ptype_eval (struct expression *exp)
 190 {
 191   if (exp->elts[0].opcode == OP_TYPE)
 192     {
 193       return (exp->elts[1].type);
 194     }
 195   else
 196     {
 197       return (NULL);
 198     }
 199 }
 200
 201 /* TYPENAME is either the name of a type, or an expression.  */
 202
 203 /* ARGSUSED */
 204 static void
 205 ptype_command (char *typename, int from_tty)
 206 {
 207   register struct type *type;
 208   struct expression *expr;
 209   register struct cleanup *old_chain;
 210
 211   if (typename == NULL)
 212     {
 213       /* Print type of last thing in value history. */
 214       whatis_exp (typename, 1);
 215     }
 216   else
 217     {
 218       expr = parse_expression (typename);
 219       old_chain = make_cleanup (free_current_contents, &expr);
 220       type = ptype_eval (expr);
 221       if (type != NULL)
 222         {
 223           /* User did "ptype <typename>" */
 224           printf_filtered ("type = ");
 225           type_print (type, "", gdb_stdout, 1);
 226           printf_filtered ("\n");
 227           do_cleanups (old_chain);
 228         }
 229       else
 230         {
 231           /* User did "ptype <symbolname>" */
 232           do_cleanups (old_chain);
 233           whatis_exp (typename, 1);
 234         }
 235     }
 236 }
 237
 238 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 239    Used to print data from type structures in a specified type.  For example,
 240    array bounds may be characters or booleans in some languages, and this
 241    allows the ranges to be printed in their "natural" form rather than as
 242    decimal integer values.
 243
 244    FIXME:  This is here simply because only the type printing routines
 245    currently use it, and it wasn't clear if it really belonged somewhere
 246    else (like printcmd.c).  There are a lot of other gdb routines that do
 247    something similar, but they are generally concerned with printing values
 248    that come from the inferior in target byte order and target size. */
 249
 250 void
 251 print_type_scalar (struct type *type, LONGEST val, struct ui_file *stream)
 252 {
 253   unsigned int i;
 254   unsigned len;
 255
 256   CHECK_TYPEDEF (type);
 257
 258   switch (TYPE_CODE (type))
 259     {
 260
 261     case TYPE_CODE_ENUM:
 262       len = TYPE_NFIELDS (type);
 263       for (i = 0; i < len; i++)
 264         {
 265           if (TYPE_FIELD_BITPOS (type, i) == val)
 266             {
 267               break;
 268             }
 269         }
 270       if (i < len)
 271         {
 272           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 273         }
 274       else
 275         {
 276           print_longest (stream, 'd', 0, val);
 277         }
 278       break;
 279
 280     case TYPE_CODE_INT:
 281       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 282       break;
 283
 284     case TYPE_CODE_CHAR:
 285       LA_PRINT_CHAR ((unsigned char) val, stream);
 286       break;
 287
 288     case TYPE_CODE_BOOL:
 289       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 290       break;
 291
 292     case TYPE_CODE_RANGE:
 293       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 294       return;
 295
 296     case TYPE_CODE_UNDEF:
 297     case TYPE_CODE_PTR:
 298     case TYPE_CODE_ARRAY:
 299     case TYPE_CODE_STRUCT:
 300     case TYPE_CODE_UNION:
 301     case TYPE_CODE_FUNC:
 302     case TYPE_CODE_FLT:
 303     case TYPE_CODE_VOID:
 304     case TYPE_CODE_SET:
 305     case TYPE_CODE_STRING:
 306     case TYPE_CODE_ERROR:
 307     case TYPE_CODE_MEMBER:
 308     case TYPE_CODE_METHOD:
 309     case TYPE_CODE_REF:
 310       error ("internal error: unhandled type in print_type_scalar");
 311       break;
 312
 313     default:
 314       error ("Invalid type code in symbol table.");
 315     }
 316   gdb_flush (stream);
 317 }
 318
 319 /* Dump details of a type specified either directly or indirectly.
 320    Uses the same sort of type lookup mechanism as ptype_command()
 321    and whatis_command(). */
 322
 323 void
 324 maintenance_print_type (char *typename, int from_tty)
 325 {
 326   struct value *val;
 327   register struct type *type;
 328   register struct cleanup *old_chain;
 329   struct expression *expr;
 330
 331   if (typename != NULL)
 332     {
 333       expr = parse_expression (typename);
 334       old_chain = make_cleanup (free_current_contents, &expr);
 335       if (expr->elts[0].opcode == OP_TYPE)
 336         {
 337           /* The user expression names a type directly, just use that type. */
 338           type = expr->elts[1].type;
 339         }
 340       else
 341         {
 342           /* The user expression may name a type indirectly by naming an
 343              object of that type.  Find that indirectly named type. */
 344           val = evaluate_type (expr);
 345           type = VALUE_TYPE (val);
 346         }
 347       if (type != NULL)
 348         {
 349           recursive_dump_type (type, 0);
 350         }
 351       do_cleanups (old_chain);
 352     }
 353 }
 354 \f
 355
 356 void
 357 _initialize_typeprint (void)
 358 {
 359
 360   add_com ("ptype", class_vars, ptype_command,
 361            "Print definition of type TYPE.\n\
 362 Argument may be a type name defined by typedef, or \"struct STRUCT-TAG\"\n\
 363 or \"class CLASS-NAME\" or \"union UNION-TAG\" or \"enum ENUM-TAG\".\n\
 364 The selected stack frame's lexical context is used to look up the name.");
 365
 366   add_com ("whatis", class_vars, whatis_command,
 367            "Print data type of expression EXP.");
 368
 369 }