gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2    Copyright 1986, 88, 89, 91, 92, 93, 1998 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include "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 "demangle.h"
  34
  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 PARAMS ((void));
  43
  44 static void
  45 ptype_command PARAMS ((char *, int));
  46
  47 static struct type *
  48   ptype_eval PARAMS ((struct expression *));
  49
  50 static void
  51 whatis_command PARAMS ((char *, int));
  52
  53 static void
  54 whatis_exp PARAMS ((char *, int));
  55
  56 /* Print a description of a type TYPE in the form of a declaration of a
  57    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
  58    Output goes to STREAM (via stdio).
  59    If SHOW is positive, we show the contents of the outermost level
  60    of structure even if there is a type name that could be used instead.
  61    If SHOW is negative, we never show the details of elements' types.  */
  62
  63 void
  64 type_print (type, varstring, stream, show)
  65      struct type *type;
  66      char *varstring;
  67      GDB_FILE *stream;
  68      int show;
  69 {
  70   LA_PRINT_TYPE (type, varstring, stream, show, 0);
  71 }
  72
  73 /* Print type of EXP, or last thing in value history if EXP == NULL.
  74    show is passed to type_print.  */
  75
  76 static void
  77 whatis_exp (exp, show)
  78      char *exp;
  79      int show;
  80 {
  81   struct expression *expr;
  82   register value_ptr val;
  83   register struct cleanup *old_chain = NULL;
  84   struct type *real_type = NULL;
  85   int full = 0;
  86   int top = -1;
  87   int using_enc = 0;
  88
  89   if (exp)
  90     {
  91       expr = parse_expression (exp);
  92       old_chain = make_cleanup ((make_cleanup_func) free_current_contents,
  93                                 &expr);
  94       val = evaluate_type (expr);
  95     }
  96   else
  97     val = access_value_history (0);
  98
  99   real_type = value_rtti_type (val, &full, &top, &using_enc);
 100
 101   printf_filtered ("type = ");
 102
 103   if (real_type && objectprint)
 104     printf_filtered ("/* real type = %s%s */\n",
 105                      TYPE_NAME (real_type),
 106                      full ? "" : " (incomplete object)");
 107   /* FIXME: maybe better to use type_print (real_type, "", gdb_stdout, -1); */
 108
 109   type_print (VALUE_TYPE (val), "", gdb_stdout, show);
 110   printf_filtered ("\n");
 111
 112   if (exp)
 113     do_cleanups (old_chain);
 114 }
 115
 116 /* ARGSUSED */
 117 static void
 118 whatis_command (exp, from_tty)
 119      char *exp;
 120      int from_tty;
 121 {
 122   /* Most of the time users do not want to see all the fields
 123      in a structure.  If they do they can use the "ptype" command.
 124      Hence the "-1" below.  */
 125   whatis_exp (exp, -1);
 126 }
 127
 128 /* Simple subroutine for ptype_command.  */
 129
 130 static struct type *
 131 ptype_eval (exp)
 132      struct expression *exp;
 133 {
 134   if (exp->elts[0].opcode == OP_TYPE)
 135     {
 136       return (exp->elts[1].type);
 137     }
 138   else
 139     {
 140       return (NULL);
 141     }
 142 }
 143
 144 /* TYPENAME is either the name of a type, or an expression.  */
 145
 146 /* ARGSUSED */
 147 static void
 148 ptype_command (typename, from_tty)
 149      char *typename;
 150      int from_tty;
 151 {
 152   register struct type *type;
 153   struct expression *expr;
 154   register struct cleanup *old_chain;
 155
 156   if (typename == NULL)
 157     {
 158       /* Print type of last thing in value history. */
 159       whatis_exp (typename, 1);
 160     }
 161   else
 162     {
 163       expr = parse_expression (typename);
 164       old_chain = make_cleanup ((make_cleanup_func) free_current_contents,
 165                                 &expr);
 166       type = ptype_eval (expr);
 167       if (type != NULL)
 168         {
 169           /* User did "ptype <typename>" */
 170           printf_filtered ("type = ");
 171           type_print (type, "", gdb_stdout, 1);
 172           printf_filtered ("\n");
 173           do_cleanups (old_chain);
 174         }
 175       else
 176         {
 177           /* User did "ptype <symbolname>" */
 178           do_cleanups (old_chain);
 179           whatis_exp (typename, 1);
 180         }
 181     }
 182 }
 183
 184 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 185    Used to print data from type structures in a specified type.  For example,
 186    array bounds may be characters or booleans in some languages, and this
 187    allows the ranges to be printed in their "natural" form rather than as
 188    decimal integer values.
 189
 190    FIXME:  This is here simply because only the type printing routines
 191    currently use it, and it wasn't clear if it really belonged somewhere
 192    else (like printcmd.c).  There are a lot of other gdb routines that do
 193    something similar, but they are generally concerned with printing values
 194    that come from the inferior in target byte order and target size. */
 195
 196 void
 197 print_type_scalar (type, val, stream)
 198      struct type *type;
 199      LONGEST val;
 200      GDB_FILE *stream;
 201 {
 202   unsigned int i;
 203   unsigned len;
 204
 205   CHECK_TYPEDEF (type);
 206
 207   switch (TYPE_CODE (type))
 208     {
 209
 210     case TYPE_CODE_ENUM:
 211       len = TYPE_NFIELDS (type);
 212       for (i = 0; i < len; i++)
 213         {
 214           if (TYPE_FIELD_BITPOS (type, i) == val)
 215             {
 216               break;
 217             }
 218         }
 219       if (i < len)
 220         {
 221           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 222         }
 223       else
 224         {
 225           print_longest (stream, 'd', 0, val);
 226         }
 227       break;
 228
 229     case TYPE_CODE_INT:
 230       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 231       break;
 232
 233     case TYPE_CODE_CHAR:
 234       LA_PRINT_CHAR ((unsigned char) val, stream);
 235       break;
 236
 237     case TYPE_CODE_BOOL:
 238       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 239       break;
 240
 241     case TYPE_CODE_RANGE:
 242       print_type_scalar (TYPE_TARGET_TYPE (type), val, stream);
 243       return;
 244
 245     case TYPE_CODE_UNDEF:
 246     case TYPE_CODE_PTR:
 247     case TYPE_CODE_ARRAY:
 248     case TYPE_CODE_STRUCT:
 249     case TYPE_CODE_UNION:
 250     case TYPE_CODE_FUNC:
 251     case TYPE_CODE_FLT:
 252     case TYPE_CODE_VOID:
 253     case TYPE_CODE_SET:
 254     case TYPE_CODE_STRING:
 255     case TYPE_CODE_ERROR:
 256     case TYPE_CODE_MEMBER:
 257     case TYPE_CODE_METHOD:
 258     case TYPE_CODE_REF:
 259       error ("internal error: unhandled type in print_type_scalar");
 260       break;
 261
 262     default:
 263       error ("Invalid type code in symbol table.");
 264     }
 265   gdb_flush (stream);
 266 }
 267
 268 /* Dump details of a type specified either directly or indirectly.
 269    Uses the same sort of type lookup mechanism as ptype_command()
 270    and whatis_command(). */
 271
 272 void
 273 maintenance_print_type (typename, from_tty)
 274      char *typename;
 275      int from_tty;
 276 {
 277   register value_ptr val;
 278   register struct type *type;
 279   register struct cleanup *old_chain;
 280   struct expression *expr;
 281
 282   if (typename != NULL)
 283     {
 284       expr = parse_expression (typename);
 285       old_chain = make_cleanup ((make_cleanup_func) free_current_contents, &expr);
 286       if (expr->elts[0].opcode == OP_TYPE)
 287         {
 288           /* The user expression names a type directly, just use that type. */
 289           type = expr->elts[1].type;
 290         }
 291       else
 292         {
 293           /* The user expression may name a type indirectly by naming an
 294              object of that type.  Find that indirectly named type. */
 295           val = evaluate_type (expr);
 296           type = VALUE_TYPE (val);
 297         }
 298       if (type != NULL)
 299         {
 300           recursive_dump_type (type, 0);
 301         }
 302       do_cleanups (old_chain);
 303     }
 304 }
 305 \f
 306
 307 void
 308 _initialize_typeprint ()
 309 {
 310
 311   add_com ("ptype", class_vars, ptype_command,
 312            "Print definition of type TYPE.\n\
 313 Argument may be a type name defined by typedef, or \"struct STRUCT-TAG\"\n\
 314 or \"class CLASS-NAME\" or \"union UNION-TAG\" or \"enum ENUM-TAG\".\n\
 315 The selected stack frame's lexical context is used to look up the name.");
 316
 317   add_com ("whatis", class_vars, whatis_command,
 318            "Print data type of expression EXP.");
 319
 320 }