xref: /openbsd-src/gnu/usr.bin/binutils/gdb/demangle.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /* Basic C++ demangling support for GDB.
2    Copyright 1991, 1992, 1996 Free Software Foundation, Inc.
3    Written by Fred Fish at Cygnus Support.
4 
5 This file is part of GDB.
6 
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11 
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 GNU General Public License for more details.
16 
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
20 
21 
22 /*  This file contains support code for C++ demangling that is common
23     to a styles of demangling, and GDB specific. */
24 
25 #include "defs.h"
26 #include "command.h"
27 #include "gdbcmd.h"
28 #include "demangle.h"
29 #include "gdb_string.h"
30 
31 /* Select the default C++ demangling style to use.  The default is "auto",
32    which allows gdb to attempt to pick an appropriate demangling style for
33    the executable it has loaded.  It can be set to a specific style ("gnu",
34    "lucid", "arm", etc.) in which case gdb will never attempt to do auto
35    selection of the style unless you do an explicit "set demangle auto".
36    To select one of these as the default, set DEFAULT_DEMANGLING_STYLE in
37    the appropriate target configuration file. */
38 
39 #ifndef DEFAULT_DEMANGLING_STYLE
40 # define DEFAULT_DEMANGLING_STYLE AUTO_DEMANGLING_STYLE_STRING
41 #endif
42 
43 /* String name for the current demangling style.  Set by the "set demangling"
44    command, printed as part of the output by the "show demangling" command. */
45 
46 static char *current_demangling_style_string;
47 
48 /* List of supported demangling styles.  Contains the name of the style as
49    seen by the user, and the enum value that corresponds to that style. */
50 
51 static const struct demangler
52 {
53   char *demangling_style_name;
54   enum demangling_styles demangling_style;
55   char *demangling_style_doc;
56 } demanglers [] =
57 {
58   {AUTO_DEMANGLING_STYLE_STRING,
59      auto_demangling,
60      "Automatic selection based on executable"},
61   {GNU_DEMANGLING_STYLE_STRING,
62      gnu_demangling,
63      "GNU (g++) style demangling"},
64   {LUCID_DEMANGLING_STYLE_STRING,
65      lucid_demangling,
66      "Lucid (lcc) style demangling"},
67   {ARM_DEMANGLING_STYLE_STRING,
68      arm_demangling,
69      "ARM style demangling"},
70   {NULL, unknown_demangling, NULL}
71 };
72 
73 static void
74 set_demangling_command PARAMS ((char *, int, struct cmd_list_element *));
75 
76 /* set current demangling style.  called by the "set demangling" command
77    after it has updated the current_demangling_style_string to match
78    what the user has entered.
79 
80    if the user has entered a string that matches a known demangling style
81    name in the demanglers[] array then just leave the string alone and update
82    the current_demangling_style enum value to match.
83 
84    if the user has entered a string that doesn't match, including an empty
85    string, then print a list of the currently known styles and restore
86    the current_demangling_style_string to match the current_demangling_style
87    enum value.
88 
89    Note:  Assumes that current_demangling_style_string always points to
90    a malloc'd string, even if it is a null-string. */
91 
92 static void
93 set_demangling_command (ignore, from_tty, c)
94      char *ignore;
95      int from_tty;
96      struct cmd_list_element *c;
97 {
98   const struct demangler *dem;
99 
100   /*  First just try to match whatever style name the user supplied with
101       one of the known ones.  Don't bother special casing for an empty
102       name, we just treat it as any other style name that doesn't match.
103       If we match, update the current demangling style enum. */
104 
105   for (dem = demanglers; dem -> demangling_style_name != NULL; dem++)
106     {
107       if (STREQ (current_demangling_style_string,
108 		  dem -> demangling_style_name))
109 	{
110 	  current_demangling_style = dem -> demangling_style;
111 	  break;
112 	}
113     }
114 
115   /* Check to see if we found a match.  If not, gripe about any non-empty
116      style name and supply a list of valid ones.  FIXME:  This should
117      probably be done with some sort of completion and with help. */
118 
119   if (dem -> demangling_style_name == NULL)
120     {
121       if (*current_demangling_style_string != '\0')
122 	{
123 	  printf_unfiltered ("Unknown demangling style `%s'.\n",
124 		  current_demangling_style_string);
125 	}
126       printf_unfiltered ("The currently understood settings are:\n\n");
127       for (dem = demanglers; dem -> demangling_style_name != NULL; dem++)
128 	{
129 	  printf_unfiltered ("%-10s %s\n", dem -> demangling_style_name,
130 		  dem -> demangling_style_doc);
131 	  if (dem -> demangling_style == current_demangling_style)
132 	    {
133 	      free (current_demangling_style_string);
134 	      current_demangling_style_string =
135 		savestring (dem -> demangling_style_name,
136 			    strlen (dem -> demangling_style_name));
137 	    }
138 	}
139       if (current_demangling_style == unknown_demangling)
140 	{
141 	  /* This can happen during initialization if gdb is compiled with
142 	     a DEMANGLING_STYLE value that is unknown, so pick the first
143 	     one as the default. */
144 	  current_demangling_style = demanglers[0].demangling_style;
145 	  current_demangling_style_string =
146 	    savestring (demanglers[0].demangling_style_name,
147 			strlen (demanglers[0].demangling_style_name));
148 	  warning ("`%s' style demangling chosen as the default.\n",
149 		   current_demangling_style_string);
150 	}
151     }
152 }
153 
154 /* Fake a "set demangling" command. */
155 
156 void
157 set_demangling_style (style)
158      char *style;
159 {
160   if (current_demangling_style_string != NULL)
161     {
162       free (current_demangling_style_string);
163     }
164   current_demangling_style_string = savestring (style, strlen (style));
165   set_demangling_command ((char *) NULL, 0, (struct cmd_list_element *) NULL);
166 }
167 
168 /* In order to allow a single demangler executable to demangle strings
169    using various common values of CPLUS_MARKER, as well as any specific
170    one set at compile time, we maintain a string containing all the
171    commonly used ones, and check to see if the marker we are looking for
172    is in that string.  CPLUS_MARKER is usually '$' on systems where the
173    assembler can deal with that.  Where the assembler can't, it's usually
174    '.' (but on many systems '.' is used for other things).  We put the
175    current defined CPLUS_MARKER first (which defaults to '$'), followed
176    by the next most common value, followed by an explicit '$' in case
177    the value of CPLUS_MARKER is not '$'.
178 
179    We could avoid this if we could just get g++ to tell us what the actual
180    cplus marker character is as part of the debug information, perhaps by
181    ensuring that it is the character that terminates the gcc<n>_compiled
182    marker symbol (FIXME). */
183 
184 static char cplus_markers[] = { CPLUS_MARKER, '.', '$', '\0' };
185 
186 int
187 is_cplus_marker (c)
188      int c;
189 {
190   return c && strchr (cplus_markers, c) != NULL;
191 }
192 
193 void
194 _initialize_demangler ()
195 {
196    struct cmd_list_element *set, *show;
197 
198    set = add_set_cmd ("demangle-style", class_support, var_string_noescape,
199 		      (char *) &current_demangling_style_string,
200 		      "Set the current C++ demangling style.\n\
201 Use `set demangle-style' without arguments for a list of demangling styles.",
202 		      &setlist);
203    show = add_show_from_set (set, &showlist);
204    set -> function.sfunc = set_demangling_command;
205 
206    /* Set the default demangling style chosen at compilation time. */
207    set_demangling_style (DEFAULT_DEMANGLING_STYLE);
208    set_cplus_marker_for_demangling (CPLUS_MARKER);
209 }
210