gdb/typeprint.c

   1 /* Language independent support for printing types for GDB, the GNU debugger.
   2    Copyright 1986, 1988, 1989, 1991, 1992, 1993 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #include "defs.h"
  21 #include "obstack.h"
  22 #include "bfd.h"                /* Binary File Description */
  23 #include "symtab.h"
  24 #include "gdbtypes.h"
  25 #include "expression.h"
  26 #include "value.h"
  27 #include "gdbcore.h"
  28 #include "command.h"
  29 #include "gdbcmd.h"
  30 #include "target.h"
  31 #include "language.h"
  32 #include "demangle.h"
  33
  34 #include <string.h>
  35 #include <errno.h>
  36
  37 static void
  38 ptype_command PARAMS ((char *, int));
  39
  40 static struct type *
  41 ptype_eval PARAMS ((struct expression *));
  42
  43 static void
  44 whatis_command PARAMS ((char *, int));
  45
  46 static void
  47 whatis_exp PARAMS ((char *, int));
  48
  49 /* Print a description of a type TYPE in the form of a declaration of a
  50    variable named VARSTRING.  (VARSTRING is demangled if necessary.)
  51    Output goes to STREAM (via stdio).
  52    If SHOW is positive, we show the contents of the outermost level
  53    of structure even if there is a type name that could be used instead.
  54    If SHOW is negative, we never show the details of elements' types.  */
  55
  56 void
  57 type_print (type, varstring, stream, show)
  58      struct type *type;
  59      char *varstring;
  60      FILE *stream;
  61      int show;
  62 {
  63   LA_PRINT_TYPE (type, varstring, stream, show, 0);
  64 }
  65
  66 /* Print type of EXP, or last thing in value history if EXP == NULL.
  67    show is passed to type_print.  */
  68
  69 static void
  70 whatis_exp (exp, show)
  71      char *exp;
  72      int show;
  73 {
  74   struct expression *expr;
  75   register value val;
  76   register struct cleanup *old_chain = NULL;
  77
  78   if (exp)
  79     {
  80       expr = parse_expression (exp);
  81       old_chain = make_cleanup (free_current_contents, &expr);
  82       val = evaluate_type (expr);
  83     }
  84   else
  85     val = access_value_history (0);
  86
  87   printf_filtered ("type = ");
  88   type_print (VALUE_TYPE (val), "", stdout, show);
  89   printf_filtered ("\n");
  90
  91   if (exp)
  92     do_cleanups (old_chain);
  93 }
  94
  95 /* ARGSUSED */
  96 static void
  97 whatis_command (exp, from_tty)
  98      char *exp;
  99      int from_tty;
 100 {
 101   /* Most of the time users do not want to see all the fields
 102      in a structure.  If they do they can use the "ptype" command.
 103      Hence the "-1" below.  */
 104   whatis_exp (exp, -1);
 105 }
 106
 107 /* Simple subroutine for ptype_command.  */
 108
 109 static struct type *
 110 ptype_eval (exp)
 111      struct expression *exp;
 112 {
 113   if (exp->elts[0].opcode == OP_TYPE)
 114     {
 115       return (exp->elts[1].type);
 116     }
 117   else
 118     {
 119       return (NULL);
 120     }
 121 }
 122
 123 /* TYPENAME is either the name of a type, or an expression.  */
 124
 125 /* ARGSUSED */
 126 static void
 127 ptype_command (typename, from_tty)
 128      char *typename;
 129      int from_tty;
 130 {
 131   register struct type *type;
 132   struct expression *expr;
 133   register struct cleanup *old_chain;
 134
 135   if (typename == NULL)
 136     {
 137       /* Print type of last thing in value history. */
 138       whatis_exp (typename, 1);
 139     }
 140   else
 141     {
 142       expr = parse_expression (typename);
 143       old_chain = make_cleanup (free_current_contents, &expr);
 144       type = ptype_eval (expr);
 145       if (type != NULL)
 146         {
 147           /* User did "ptype <typename>" */
 148           printf_filtered ("type = ");
 149           type_print (type, "", stdout, 1);
 150           printf_filtered ("\n");
 151           do_cleanups (old_chain);
 152         }
 153       else
 154         {
 155           /* User did "ptype <symbolname>" */
 156           do_cleanups (old_chain);
 157           whatis_exp (typename, 1);
 158         }
 159     }
 160 }
 161
 162 /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
 163    Used to print data from type structures in a specified type.  For example,
 164    array bounds may be characters or booleans in some languages, and this
 165    allows the ranges to be printed in their "natural" form rather than as
 166    decimal integer values.
 167
 168    FIXME:  This is here simply because only the type printing routines
 169    currently use it, and it wasn't clear if it really belonged somewhere
 170    else (like printcmd.c).  There are a lot of other gdb routines that do
 171    something similar, but they are generally concerned with printing values
 172    that come from the inferior in target byte order and target size. */
 173
 174 void
 175 print_type_scalar (type, val, stream)
 176      struct type *type;
 177      LONGEST val;
 178      FILE *stream;
 179 {
 180   unsigned int i;
 181   unsigned len;
 182
 183   switch (TYPE_CODE (type))
 184     {
 185
 186     case TYPE_CODE_ENUM:
 187       len = TYPE_NFIELDS (type);
 188       for (i = 0; i < len; i++)
 189         {
 190           if (TYPE_FIELD_BITPOS (type, i) == val)
 191             {
 192               break;
 193             }
 194         }
 195       if (i < len)
 196         {
 197           fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
 198         }
 199       else
 200         {
 201           print_longest (stream, 'd', 0, val);
 202         }
 203       break;
 204
 205     case TYPE_CODE_INT:
 206       print_longest (stream, TYPE_UNSIGNED (type) ? 'u' : 'd', 0, val);
 207       break;
 208
 209     case TYPE_CODE_CHAR:
 210       LA_PRINT_CHAR ((unsigned char) val, stream);
 211       break;
 212
 213     case TYPE_CODE_BOOL:
 214       fprintf_filtered (stream, val ? "TRUE" : "FALSE");
 215       break;
 216
 217     case TYPE_CODE_UNDEF:
 218     case TYPE_CODE_PTR:
 219     case TYPE_CODE_ARRAY:
 220     case TYPE_CODE_STRUCT:
 221     case TYPE_CODE_UNION:
 222     case TYPE_CODE_FUNC:
 223     case TYPE_CODE_FLT:
 224     case TYPE_CODE_VOID:
 225     case TYPE_CODE_SET:
 226     case TYPE_CODE_RANGE:
 227     case TYPE_CODE_STRING:
 228     case TYPE_CODE_ERROR:
 229     case TYPE_CODE_MEMBER:
 230     case TYPE_CODE_METHOD:
 231     case TYPE_CODE_REF:
 232       error ("internal error: unhandled type in print_type_scalar");
 233       break;
 234
 235     default:
 236       error ("Invalid type code in symbol table.");
 237     }
 238   fflush (stream);
 239 }
 240
 241 #if MAINTENANCE_CMDS
 242
 243 /* Dump details of a type specified either directly or indirectly.
 244    Uses the same sort of type lookup mechanism as ptype_command()
 245    and whatis_command(). */
 246
 247 void
 248 maintenance_print_type (typename, from_tty)
 249      char *typename;
 250      int from_tty;
 251 {
 252   register value val;
 253   register struct type *type;
 254   register struct cleanup *old_chain;
 255   struct expression *expr;
 256
 257   if (typename != NULL)
 258   {
 259     expr = parse_expression (typename);
 260     old_chain = make_cleanup (free_current_contents, &expr);
 261     if (expr -> elts[0].opcode == OP_TYPE)
 262       {
 263         /* The user expression names a type directly, just use that type. */
 264         type = expr -> elts[1].type;
 265       }
 266     else
 267       {
 268         /* The user expression may name a type indirectly by naming an
 269            object of that type.  Find that indirectly named type. */
 270         val = evaluate_type (expr);
 271         type = VALUE_TYPE (val);
 272       }
 273     if (type != NULL)
 274       {
 275         recursive_dump_type (type, 0);
 276       }
 277     do_cleanups (old_chain);
 278   }
 279 }
 280
 281 #endif  /* MAINTENANCE_CMDS */
 282
 283 \f
 284 void
 285 _initialize_typeprint ()
 286 {
 287
 288   add_com ("ptype", class_vars, ptype_command,
 289            "Print definition of type TYPE.\n\
 290 Argument may be a type name defined by typedef, or \"struct STRUCT-TAG\"\n\
 291 or \"class CLASS-NAME\" or \"union UNION-TAG\" or \"enum ENUM-TAG\".\n\
 292 The selected stack frame's lexical context is used to look up the name.");
 293
 294   add_com ("whatis", class_vars, whatis_command,
 295            "Print data type of expression EXP.");
 296
 297 }