gdb/demangle.c

   1 /* Basic C++ demangling support for GDB.
   2
   3    Copyright (C) 1991-2015 Free Software Foundation, Inc.
   4
   5    Written by Fred Fish at Cygnus Support.
   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
  23 /*  This file contains support code for C++ demangling that is common
  24    to a styles of demangling, and GDB specific.  */
  25
  26 #include "defs.h"
  27 #include "cli/cli-utils.h" /* for skip_to_space */
  28 #include "command.h"
  29 #include "gdbcmd.h"
  30 #include "demangle.h"
  31 #include "gdb-demangle.h"
  32 #include "language.h"
  33
  34 /* Select the default C++ demangling style to use.  The default is "auto",
  35    which allows gdb to attempt to pick an appropriate demangling style for
  36    the executable it has loaded.  It can be set to a specific style ("gnu",
  37    "lucid", "arm", "hp", etc.) in which case gdb will never attempt to do auto
  38    selection of the style unless you do an explicit "set demangle auto".
  39    To select one of these as the default, set DEFAULT_DEMANGLING_STYLE in
  40    the appropriate target configuration file.  */
  41
  42 #ifndef DEFAULT_DEMANGLING_STYLE
  43 #define DEFAULT_DEMANGLING_STYLE AUTO_DEMANGLING_STYLE_STRING
  44 #endif
  45
  46 static void demangle_command (char *, int);
  47
  48 /* See documentation in gdb-demangle.h.  */
  49 int demangle = 1;
  50
  51 static void
  52 show_demangle (struct ui_file *file, int from_tty,
  53                struct cmd_list_element *c, const char *value)
  54 {
  55   fprintf_filtered (file,
  56                     _("Demangling of encoded C++/ObjC names "
  57                       "when displaying symbols is %s.\n"),
  58                     value);
  59 }
  60
  61 /* See documentation in gdb-demangle.h.  */
  62 int asm_demangle = 0;
  63
  64 static void
  65 show_asm_demangle (struct ui_file *file, int from_tty,
  66                    struct cmd_list_element *c, const char *value)
  67 {
  68   fprintf_filtered (file,
  69                     _("Demangling of C++/ObjC names in "
  70                       "disassembly listings is %s.\n"),
  71                     value);
  72 }
  73
  74 /* String name for the current demangling style.  Set by the
  75    "set demangle-style" command, printed as part of the output by the
  76    "show demangle-style" command.  */
  77
  78 static const char *current_demangling_style_string;
  79
  80 /* The array of names of the known demanglyng styles.  Generated by
  81    _initialize_demangler from libiberty_demanglers[] array.  */
  82
  83 static const char **demangling_style_names;
  84 static void
  85 show_demangling_style_names(struct ui_file *file, int from_tty,
  86                             struct cmd_list_element *c, const char *value)
  87 {
  88   fprintf_filtered (file, _("The current C++ demangling style is \"%s\".\n"),
  89                     value);
  90 }
  91
  92 /* Set current demangling style.  Called by the "set demangle-style"
  93    command after it has updated the current_demangling_style_string to
  94    match what the user has entered.
  95
  96    If the user has entered a string that matches a known demangling style
  97    name in the demanglers[] array then just leave the string alone and update
  98    the current_demangling_style enum value to match.
  99
 100    If the user has entered a string that doesn't match, including an empty
 101    string, then print a list of the currently known styles and restore
 102    the current_demangling_style_string to match the current_demangling_style
 103    enum value.
 104
 105    Note:  Assumes that current_demangling_style_string always points to
 106    a malloc'd string, even if it is a null-string.  */
 107
 108 static void
 109 set_demangling_command (char *ignore, int from_tty, struct cmd_list_element *c)
 110 {
 111   const struct demangler_engine *dem;
 112   int i;
 113
 114   /*  First just try to match whatever style name the user supplied with
 115      one of the known ones.  Don't bother special casing for an empty
 116      name, we just treat it as any other style name that doesn't match.
 117      If we match, update the current demangling style enum.  */
 118
 119   for (dem = libiberty_demanglers, i = 0;
 120        dem->demangling_style != unknown_demangling;
 121        dem++)
 122     {
 123       if (strcmp (current_demangling_style_string,
 124                   dem->demangling_style_name) == 0)
 125         {
 126           current_demangling_style = dem->demangling_style;
 127           current_demangling_style_string = demangling_style_names[i];
 128           break;
 129         }
 130       i++;
 131     }
 132
 133   /* We should have found a match, given we only add known styles to
 134      the enumeration list.  */
 135   gdb_assert (dem->demangling_style != unknown_demangling);
 136 }
 137
 138 /* G++ uses a special character to indicate certain internal names.  Which
 139    character it is depends on the platform:
 140    - Usually '$' on systems where the assembler will accept that
 141    - Usually '.' otherwise (this includes most sysv4-like systems and most
 142      ELF targets)
 143    - Occasionally '_' if neither of the above is usable
 144
 145    We check '$' first because it is the safest, and '.' often has another
 146    meaning.  We don't currently try to handle '_' because the precise forms
 147    of the names are different on those targets.  */
 148
 149 static char cplus_markers[] = {'$', '.', '\0'};
 150
 151 /* See documentation in gdb-demangle.h.  */
 152
 153 int
 154 is_cplus_marker (int c)
 155 {
 156   return c && strchr (cplus_markers, c) != NULL;
 157 }
 158
 159 /* Demangle the given string in the current language.  */
 160
 161 static void
 162 demangle_command (char *args, int from_tty)
 163 {
 164   char *demangled, *name, *lang_name = NULL;
 165   char *arg_buf, *arg_start;
 166   int processing_args = 1;
 167   const struct language_defn *lang;
 168   struct cleanup *cleanups;
 169
 170   arg_buf = xstrdup (args != NULL ? args : "");
 171   cleanups = make_cleanup (xfree, arg_buf);
 172   arg_start = arg_buf;
 173
 174   while (processing_args
 175          && *arg_start == '-')
 176     {
 177       char *p = skip_to_space (arg_start);
 178
 179       if (strncmp (arg_start, "-l", p - arg_start) == 0)
 180         {
 181           char *lang_name_end;
 182
 183           lang_name = skip_spaces (p);
 184           lang_name_end = skip_to_space (lang_name);
 185           lang_name = savestring (lang_name, lang_name_end - lang_name);
 186           make_cleanup (xfree, lang_name);
 187           p = lang_name_end;
 188         }
 189       else if (strncmp (arg_start, "--", p - arg_start) == 0)
 190         processing_args = 0;
 191       else
 192         {
 193           *p = '\0';
 194           error (_("Unrecognized option '%s' to demangle command.  "
 195                    "Try \"help demangle\"."), arg_start);
 196         }
 197
 198       arg_start = skip_spaces (p);
 199     }
 200
 201   name = arg_start;
 202
 203   if (*name == '\0')
 204     error (_("Usage: demangle [-l language] [--] name"));
 205
 206   if (lang_name != NULL)
 207     {
 208       enum language lang_enum;
 209
 210       lang_enum = language_enum (lang_name);
 211       if (lang_enum == language_unknown)
 212         error (_("Unknown language \"%s\""), lang_name);
 213       lang = language_def (lang_enum);
 214     }
 215   else
 216     lang = current_language;
 217
 218   demangled = language_demangle (lang, name, DMGL_ANSI | DMGL_PARAMS);
 219   if (demangled != NULL)
 220     {
 221       printf_filtered ("%s\n", demangled);
 222       xfree (demangled);
 223     }
 224   else
 225     error (_("Can't demangle \"%s\""), name);
 226
 227   do_cleanups (cleanups);
 228 }
 229
 230 extern initialize_file_ftype _initialize_demangler; /* -Wmissing-prototypes */
 231
 232 void
 233 _initialize_demangler (void)
 234 {
 235   int i, ndems;
 236
 237   /* Fill the demangling_style_names[] array, and set the default
 238      demangling style chosen at compilation time.  */
 239   for (ndems = 0;
 240        libiberty_demanglers[ndems].demangling_style != unknown_demangling;
 241        ndems++)
 242     ;
 243   demangling_style_names = xcalloc (ndems + 1, sizeof (char *));
 244   for (i = 0;
 245        libiberty_demanglers[i].demangling_style != unknown_demangling;
 246        i++)
 247     {
 248       demangling_style_names[i]
 249         = xstrdup (libiberty_demanglers[i].demangling_style_name);
 250
 251       if (current_demangling_style_string == NULL
 252           && strcmp (DEFAULT_DEMANGLING_STYLE, demangling_style_names[i]) == 0)
 253         current_demangling_style_string = demangling_style_names[i];
 254     }
 255
 256   add_setshow_boolean_cmd ("demangle", class_support, &demangle, _("\
 257 Set demangling of encoded C++/ObjC names when displaying symbols."), _("\
 258 Show demangling of encoded C++/ObjC names when displaying symbols."), NULL,
 259                            NULL,
 260                            show_demangle,
 261                            &setprintlist, &showprintlist);
 262
 263   add_setshow_boolean_cmd ("asm-demangle", class_support, &asm_demangle, _("\
 264 Set demangling of C++/ObjC names in disassembly listings."), _("\
 265 Show demangling of C++/ObjC names in disassembly listings."), NULL,
 266                            NULL,
 267                            show_asm_demangle,
 268                            &setprintlist, &showprintlist);
 269
 270   add_setshow_enum_cmd ("demangle-style", class_support,
 271                         demangling_style_names,
 272                         &current_demangling_style_string, _("\
 273 Set the current C++ demangling style."), _("\
 274 Show the current C++ demangling style."), _("\
 275 Use `set demangle-style' without arguments for a list of demangling styles."),
 276                         set_demangling_command,
 277                         show_demangling_style_names,
 278                         &setlist, &showlist);
 279
 280   add_cmd ("demangle", class_support, demangle_command, _("\
 281 Demangle a mangled name.\n\
 282 Usage: demangle [-l language] [--] name\n\
 283 If LANGUAGE is not specified, NAME is demangled in the current language."),
 284            &cmdlist);
 285 }