gdb/gdb-demangle.c

   1 /* Basic C++ demangling support for GDB.
   2
   3    Copyright (C) 1991-2024 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 "cli/cli-utils.h"
  27 #include "command.h"
  28 #include "cli/cli-cmds.h"
  29 #include "demangle.h"
  30 #include "gdb-demangle.h"
  31 #include "language.h"
  32
  33 /* Select the default C++ demangling style to use.  The default is "auto",
  34    which allows gdb to attempt to pick an appropriate demangling style for
  35    the executable it has loaded.  It can be set to a specific style ("gnu",
  36    "lucid", "arm", "hp", etc.) in which case gdb will never attempt to do auto
  37    selection of the style unless you do an explicit "set demangle auto".
  38    To select one of these as the default, set DEFAULT_DEMANGLING_STYLE in
  39    the appropriate target configuration file.  */
  40
  41 #ifndef DEFAULT_DEMANGLING_STYLE
  42 #define DEFAULT_DEMANGLING_STYLE AUTO_DEMANGLING_STYLE_STRING
  43 #endif
  44
  45 /* See documentation in gdb-demangle.h.  */
  46 bool demangle = true;
  47
  48 static void
  49 show_demangle (struct ui_file *file, int from_tty,
  50                struct cmd_list_element *c, const char *value)
  51 {
  52   gdb_printf (file,
  53               _("Demangling of encoded C++/ObjC names "
  54                 "when displaying symbols is %s.\n"),
  55               value);
  56 }
  57
  58 /* See documentation in gdb-demangle.h.  */
  59 bool asm_demangle = false;
  60
  61 static void
  62 show_asm_demangle (struct ui_file *file, int from_tty,
  63                    struct cmd_list_element *c, const char *value)
  64 {
  65   gdb_printf (file,
  66               _("Demangling of C++/ObjC names in "
  67                 "disassembly listings is %s.\n"),
  68               value);
  69 }
  70
  71 /* String name for the current demangling style.  Set by the
  72    "set demangle-style" command, printed as part of the output by the
  73    "show demangle-style" command.  */
  74
  75 static const char *current_demangling_style_string;
  76
  77 /* The array of names of the known demangling styles.  Generated by
  78    _initialize_demangler from libiberty_demanglers[] array.  */
  79
  80 static const char **demangling_style_names;
  81 static void
  82 show_demangling_style_names(struct ui_file *file, int from_tty,
  83                             struct cmd_list_element *c, const char *value)
  84 {
  85   gdb_printf (file, _("The current C++ demangling style is \"%s\".\n"),
  86               value);
  87 }
  88
  89 /* Set current demangling style.  Called by the "set demangle-style"
  90    command after it has updated the current_demangling_style_string to
  91    match what the user has entered.
  92
  93    If the user has entered a string that matches a known demangling style
  94    name in the demanglers[] array then just leave the string alone and update
  95    the current_demangling_style enum value to match.
  96
  97    If the user has entered a string that doesn't match, including an empty
  98    string, then print a list of the currently known styles and restore
  99    the current_demangling_style_string to match the current_demangling_style
 100    enum value.
 101
 102    Note:  Assumes that current_demangling_style_string always points to
 103    a malloc'd string, even if it is a null-string.  */
 104
 105 static void
 106 set_demangling_command (const char *ignore,
 107                         int from_tty, struct cmd_list_element *c)
 108 {
 109   const struct demangler_engine *dem;
 110   int i;
 111
 112   /*  First just try to match whatever style name the user supplied with
 113      one of the known ones.  Don't bother special casing for an empty
 114      name, we just treat it as any other style name that doesn't match.
 115      If we match, update the current demangling style enum.  */
 116
 117   for (dem = libiberty_demanglers, i = 0;
 118        dem->demangling_style != unknown_demangling;
 119        dem++)
 120     {
 121       if (strcmp (current_demangling_style_string,
 122                   dem->demangling_style_name) == 0)
 123         {
 124           current_demangling_style = dem->demangling_style;
 125           current_demangling_style_string = demangling_style_names[i];
 126           break;
 127         }
 128       i++;
 129     }
 130
 131   /* We should have found a match, given we only add known styles to
 132      the enumeration list.  */
 133   gdb_assert (dem->demangling_style != unknown_demangling);
 134 }
 135
 136 /* G++ uses a special character to indicate certain internal names.  Which
 137    character it is depends on the platform:
 138    - Usually '$' on systems where the assembler will accept that
 139    - Usually '.' otherwise (this includes most sysv4-like systems and most
 140      ELF targets)
 141    - Occasionally '_' if neither of the above is usable
 142
 143    We check '$' first because it is the safest, and '.' often has another
 144    meaning.  We don't currently try to handle '_' because the precise forms
 145    of the names are different on those targets.  */
 146
 147 static char cplus_markers[] = {'$', '.', '\0'};
 148
 149 /* See documentation in gdb-demangle.h.  */
 150
 151 bool
 152 is_cplus_marker (int c)
 153 {
 154   return c && strchr (cplus_markers, c) != NULL;
 155 }
 156
 157 /* Demangle the given string in the current language.  */
 158
 159 static void
 160 demangle_command (const char *args, int from_tty)
 161 {
 162   const char *name;
 163   const char *arg_start;
 164   int processing_args = 1;
 165   const struct language_defn *lang;
 166
 167   std::string arg_buf = args != NULL ? args : "";
 168   arg_start = arg_buf.c_str ();
 169
 170   std::string lang_name;
 171   while (processing_args
 172          && *arg_start == '-')
 173     {
 174       const char *p = skip_to_space (arg_start);
 175
 176       if (strncmp (arg_start, "-l", p - arg_start) == 0)
 177         lang_name = extract_arg (&p);
 178       else if (strncmp (arg_start, "--", p - arg_start) == 0)
 179         processing_args = 0;
 180       else
 181         report_unrecognized_option_error ("demangle", arg_start);
 182
 183       arg_start = skip_spaces (p);
 184     }
 185
 186   name = arg_start;
 187
 188   if (*name == '\0')
 189     error (_("Usage: demangle [-l LANGUAGE] [--] NAME"));
 190
 191   if (!lang_name.empty ())
 192     {
 193       enum language lang_enum;
 194
 195       lang_enum = language_enum (lang_name.c_str ());
 196       if (lang_enum == language_unknown)
 197         error (_("Unknown language \"%s\""), lang_name.c_str ());
 198       lang = language_def (lang_enum);
 199     }
 200   else
 201     lang = current_language;
 202
 203   gdb::unique_xmalloc_ptr<char> demangled
 204     = lang->demangle_symbol (name, DMGL_ANSI | DMGL_PARAMS);
 205   if (demangled != NULL)
 206     gdb_printf ("%s\n", demangled.get ());
 207   else
 208     error (_("Can't demangle \"%s\""), name);
 209 }
 210
 211 void _initialize_gdb_demangle ();
 212 void
 213 _initialize_gdb_demangle ()
 214 {
 215   int i, ndems;
 216
 217   /* Fill the demangling_style_names[] array, and set the default
 218      demangling style chosen at compilation time.  */
 219   for (ndems = 0;
 220        libiberty_demanglers[ndems].demangling_style != unknown_demangling;
 221        ndems++)
 222     ;
 223   demangling_style_names = XCNEWVEC (const char *, ndems + 1);
 224   for (i = 0;
 225        libiberty_demanglers[i].demangling_style != unknown_demangling;
 226        i++)
 227     {
 228       demangling_style_names[i]
 229         = xstrdup (libiberty_demanglers[i].demangling_style_name);
 230
 231       if (current_demangling_style_string == NULL
 232           && strcmp (DEFAULT_DEMANGLING_STYLE, demangling_style_names[i]) == 0)
 233         current_demangling_style_string = demangling_style_names[i];
 234     }
 235
 236   add_setshow_boolean_cmd ("demangle", class_support, &demangle, _("\
 237 Set demangling of encoded C++/ObjC names when displaying symbols."), _("\
 238 Show demangling of encoded C++/ObjC names when displaying symbols."), NULL,
 239                            NULL,
 240                            show_demangle,
 241                            &setprintlist, &showprintlist);
 242
 243   add_setshow_boolean_cmd ("asm-demangle", class_support, &asm_demangle, _("\
 244 Set demangling of C++/ObjC names in disassembly listings."), _("\
 245 Show demangling of C++/ObjC names in disassembly listings."), NULL,
 246                            NULL,
 247                            show_asm_demangle,
 248                            &setprintlist, &showprintlist);
 249
 250   add_setshow_enum_cmd ("demangle-style", class_support,
 251                         demangling_style_names,
 252                         &current_demangling_style_string, _("\
 253 Set the current C++ demangling style."), _("\
 254 Show the current C++ demangling style."), _("\
 255 Use `set demangle-style' without arguments for a list of demangling styles."),
 256                         set_demangling_command,
 257                         show_demangling_style_names,
 258                         &setlist, &showlist);
 259
 260   add_cmd ("demangle", class_support, demangle_command, _("\
 261 Demangle a mangled name.\n\
 262 Usage: demangle [-l LANGUAGE] [--] NAME\n\
 263 If LANGUAGE is not specified, NAME is demangled in the current language."),
 264            &cmdlist);
 265 }