1 /* Command line option handling.
2 Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
25 /* Perform a binary search to find which option the command-line INPUT
26 matches. Returns its index in the option array, and N_OPTS
27 (cl_options_count) on failure.
29 This routine is quite subtle. A normal binary search is not good
30 enough because some options can be suffixed with an argument, and
31 multiple sub-matches can occur, e.g. input of "-pedantic" matching
32 the initial substring of "-pedantic-errors".
34 A more complicated example is -gstabs. It should match "-g" with
35 an argument of "stabs". Suppose, however, that the number and list
36 of switches are such that the binary search tests "-gen-decls"
37 before having tested "-g". This doesn't match, and as "-gen-decls"
38 is less than "-gstabs", it will become the lower bound of the
39 binary search range, and "-g" will never be seen. To resolve this
40 issue, 'optc-gen.awk' makes "-gen-decls" point, via the back_chain member,
41 to "-g" so that failed searches that end between "-gen-decls" and
42 the lexicographically subsequent switch know to go back and see if
43 "-g" causes a match (which it does in this example).
45 This search is done in such a way that the longest match for the
46 front end in question wins. If there is no match for the current
47 front end, the longest match for a different front end is returned
48 (or N_OPTS if none) and the caller emits an error message. */
50 find_opt (const char *input, int lang_mask)
52 size_t mn, mx, md, opt_len;
53 size_t match_wrong_lang;
57 mx = cl_options_count;
59 /* Find mn such this lexicographical inequality holds:
60 cl_options[mn] <= input < cl_options[mn + 1]. */
64 opt_len = cl_options[md].opt_len;
65 comp = strncmp (input, cl_options[md].opt_text + 1, opt_len);
73 /* This is the switch that is the best match but for a different
74 front end, or cl_options_count if there is no match at all. */
75 match_wrong_lang = cl_options_count;
77 /* Backtrace the chain of possible matches, returning the longest
78 one, if any, that fits best. With current GCC switches, this
79 loop executes at most twice. */
82 const struct cl_option *opt = &cl_options[mn];
84 /* Is the input either an exact match or a prefix that takes a
86 if (!strncmp (input, opt->opt_text + 1, opt->opt_len)
87 && (input[opt->opt_len] == '\0' || (opt->flags & CL_JOINED)))
89 /* If language is OK, return it. */
90 if (opt->flags & lang_mask)
93 /* If we haven't remembered a prior match, remember this
94 one. Any prior match is necessarily better. */
95 if (match_wrong_lang == cl_options_count)
96 match_wrong_lang = mn;
99 /* Try the next possibility. This is cl_options_count if there
101 mn = opt->back_chain;
103 while (mn != cl_options_count);
105 /* Return the best wrong match, or cl_options_count if none. */
106 return match_wrong_lang;
109 /* Return true if NEXT_OPT_IDX cancels OPT_IDX. Return false if the
110 next one is the same as ORIG_NEXT_OPT_IDX. */
113 cancel_option (int opt_idx, int next_opt_idx, int orig_next_opt_idx)
115 /* An option can be canceled by the same option or an option with
117 if (cl_options [next_opt_idx].neg_index == opt_idx)
120 if (cl_options [next_opt_idx].neg_index != orig_next_opt_idx)
121 return cancel_option (opt_idx, cl_options [next_opt_idx].neg_index,
127 /* Filter out options canceled by the ones after them. */
130 prune_options (int *argcp, char ***argvp)
133 int *options = XNEWVEC (int, argc);
134 char **argv = XNEWVEC (char *, argc);
135 int i, arg_count, need_prune = 0;
136 const struct cl_option *option;
139 /* Scan all arguments. */
140 for (i = 1; i < argc; i++)
143 const char *opt = (*argvp) [i];
145 opt_index = find_opt (opt + 1, -1);
146 if (opt_index == cl_options_count
147 && (opt[1] == 'W' || opt[1] == 'f' || opt[1] == 'm')
148 && opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-')
152 /* Drop the "no-" from negative switches. */
153 size_t len = strlen (opt) - 3;
155 dup = XNEWVEC (char, len + 1);
158 memcpy (dup + 2, opt + 5, len - 2 + 1);
161 opt_index = find_opt (opt + 1, -1);
165 if (opt_index == cl_options_count)
172 option = &cl_options[opt_index];
173 if (option->neg_index < 0)
176 /* Skip joined switches. */
177 if ((option->flags & CL_JOINED))
180 /* Reject negative form of switches that don't take negatives as
182 if (!value && (option->flags & CL_REJECT_NEGATIVE))
185 options [i] = (int) opt_index;
186 need_prune |= options [i];
192 /* Remove arguments which are negated by others after them. */
193 argv [0] = (*argvp) [0];
195 for (i = 1; i < argc; i++)
199 opt_idx = options [i];
203 for (j = i + 1; j < argc; j++)
205 next_opt_idx = options [j];
207 && cancel_option (opt_idx, next_opt_idx,
218 argv [arg_count] = (*argvp) [i];
223 if (arg_count != argc)