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14c7833c | 1 | /* Command line option handling. |
66647d44 | 2 | Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc. |
14c7833c L |
3 | |
4 | This file is part of GCC. | |
5 | ||
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 | |
9dcd6f09 | 8 | Software Foundation; either version 3, or (at your option) any later |
14c7833c L |
9 | version. |
10 | ||
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 | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
14c7833c L |
19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "intl.h" | |
23 | #include "coretypes.h" | |
24 | #include "opts.h" | |
25 | ||
26 | /* Perform a binary search to find which option the command-line INPUT | |
27 | matches. Returns its index in the option array, and N_OPTS | |
28 | (cl_options_count) on failure. | |
29 | ||
30 | This routine is quite subtle. A normal binary search is not good | |
31 | enough because some options can be suffixed with an argument, and | |
32 | multiple sub-matches can occur, e.g. input of "-pedantic" matching | |
33 | the initial substring of "-pedantic-errors". | |
34 | ||
35 | A more complicated example is -gstabs. It should match "-g" with | |
36 | an argument of "stabs". Suppose, however, that the number and list | |
37 | of switches are such that the binary search tests "-gen-decls" | |
38 | before having tested "-g". This doesn't match, and as "-gen-decls" | |
39 | is less than "-gstabs", it will become the lower bound of the | |
40 | binary search range, and "-g" will never be seen. To resolve this | |
af47e6ac | 41 | issue, 'optc-gen.awk' makes "-gen-decls" point, via the back_chain member, |
14c7833c L |
42 | to "-g" so that failed searches that end between "-gen-decls" and |
43 | the lexicographically subsequent switch know to go back and see if | |
44 | "-g" causes a match (which it does in this example). | |
45 | ||
46 | This search is done in such a way that the longest match for the | |
47 | front end in question wins. If there is no match for the current | |
48 | front end, the longest match for a different front end is returned | |
49 | (or N_OPTS if none) and the caller emits an error message. */ | |
50 | size_t | |
51 | find_opt (const char *input, int lang_mask) | |
52 | { | |
53 | size_t mn, mx, md, opt_len; | |
54 | size_t match_wrong_lang; | |
55 | int comp; | |
56 | ||
57 | mn = 0; | |
58 | mx = cl_options_count; | |
59 | ||
60 | /* Find mn such this lexicographical inequality holds: | |
61 | cl_options[mn] <= input < cl_options[mn + 1]. */ | |
62 | while (mx - mn > 1) | |
63 | { | |
64 | md = (mn + mx) / 2; | |
65 | opt_len = cl_options[md].opt_len; | |
66 | comp = strncmp (input, cl_options[md].opt_text + 1, opt_len); | |
67 | ||
68 | if (comp < 0) | |
69 | mx = md; | |
70 | else | |
71 | mn = md; | |
72 | } | |
73 | ||
74 | /* This is the switch that is the best match but for a different | |
75 | front end, or cl_options_count if there is no match at all. */ | |
76 | match_wrong_lang = cl_options_count; | |
77 | ||
78 | /* Backtrace the chain of possible matches, returning the longest | |
79 | one, if any, that fits best. With current GCC switches, this | |
80 | loop executes at most twice. */ | |
81 | do | |
82 | { | |
83 | const struct cl_option *opt = &cl_options[mn]; | |
84 | ||
85 | /* Is the input either an exact match or a prefix that takes a | |
86 | joined argument? */ | |
87 | if (!strncmp (input, opt->opt_text + 1, opt->opt_len) | |
88 | && (input[opt->opt_len] == '\0' || (opt->flags & CL_JOINED))) | |
89 | { | |
90 | /* If language is OK, return it. */ | |
91 | if (opt->flags & lang_mask) | |
92 | return mn; | |
93 | ||
94 | /* If we haven't remembered a prior match, remember this | |
95 | one. Any prior match is necessarily better. */ | |
96 | if (match_wrong_lang == cl_options_count) | |
97 | match_wrong_lang = mn; | |
98 | } | |
99 | ||
100 | /* Try the next possibility. This is cl_options_count if there | |
101 | are no more. */ | |
102 | mn = opt->back_chain; | |
103 | } | |
104 | while (mn != cl_options_count); | |
105 | ||
106 | /* Return the best wrong match, or cl_options_count if none. */ | |
107 | return match_wrong_lang; | |
108 | } | |
109 | ||
110 | /* Return true if NEXT_OPT_IDX cancels OPT_IDX. Return false if the | |
111 | next one is the same as ORIG_NEXT_OPT_IDX. */ | |
112 | ||
113 | static bool | |
114 | cancel_option (int opt_idx, int next_opt_idx, int orig_next_opt_idx) | |
115 | { | |
116 | /* An option can be canceled by the same option or an option with | |
117 | Negative. */ | |
118 | if (cl_options [next_opt_idx].neg_index == opt_idx) | |
119 | return true; | |
120 | ||
121 | if (cl_options [next_opt_idx].neg_index != orig_next_opt_idx) | |
122 | return cancel_option (opt_idx, cl_options [next_opt_idx].neg_index, | |
123 | orig_next_opt_idx); | |
b8698a0f | 124 | |
14c7833c L |
125 | return false; |
126 | } | |
127 | ||
128 | /* Filter out options canceled by the ones after them. */ | |
129 | ||
130 | void | |
131 | prune_options (int *argcp, char ***argvp) | |
132 | { | |
133 | int argc = *argcp; | |
d3bfe4de | 134 | int *options = XNEWVEC (int, argc); |
807303cf DK |
135 | /* We will only return this replacement argv if we remove at least |
136 | one argument, so it does not need to be size (argc + 1) to | |
137 | make room for the terminating NULL because we will always have | |
138 | freed up at least one slot when we end up using it at all. */ | |
d3bfe4de | 139 | char **argv = XNEWVEC (char *, argc); |
14c7833c L |
140 | int i, arg_count, need_prune = 0; |
141 | const struct cl_option *option; | |
142 | size_t opt_index; | |
143 | ||
144 | /* Scan all arguments. */ | |
145 | for (i = 1; i < argc; i++) | |
146 | { | |
147 | int value = 1; | |
148 | const char *opt = (*argvp) [i]; | |
149 | ||
150 | opt_index = find_opt (opt + 1, -1); | |
151 | if (opt_index == cl_options_count | |
152 | && (opt[1] == 'W' || opt[1] == 'f' || opt[1] == 'm') | |
153 | && opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-') | |
154 | { | |
155 | char *dup; | |
156 | ||
157 | /* Drop the "no-" from negative switches. */ | |
158 | size_t len = strlen (opt) - 3; | |
159 | ||
160 | dup = XNEWVEC (char, len + 1); | |
161 | dup[0] = '-'; | |
162 | dup[1] = opt[1]; | |
163 | memcpy (dup + 2, opt + 5, len - 2 + 1); | |
164 | opt = dup; | |
165 | value = 0; | |
166 | opt_index = find_opt (opt + 1, -1); | |
167 | free (dup); | |
168 | } | |
169 | ||
170 | if (opt_index == cl_options_count) | |
171 | { | |
172 | cont: | |
173 | options [i] = 0; | |
174 | continue; | |
175 | } | |
176 | ||
177 | option = &cl_options[opt_index]; | |
178 | if (option->neg_index < 0) | |
179 | goto cont; | |
180 | ||
faa88843 L |
181 | /* Skip joined switches. */ |
182 | if ((option->flags & CL_JOINED)) | |
183 | goto cont; | |
184 | ||
14c7833c L |
185 | /* Reject negative form of switches that don't take negatives as |
186 | unrecognized. */ | |
187 | if (!value && (option->flags & CL_REJECT_NEGATIVE)) | |
188 | goto cont; | |
189 | ||
190 | options [i] = (int) opt_index; | |
191 | need_prune |= options [i]; | |
192 | } | |
193 | ||
194 | if (!need_prune) | |
195 | goto done; | |
196 | ||
197 | /* Remove arguments which are negated by others after them. */ | |
198 | argv [0] = (*argvp) [0]; | |
199 | arg_count = 1; | |
200 | for (i = 1; i < argc; i++) | |
201 | { | |
202 | int j, opt_idx; | |
203 | ||
204 | opt_idx = options [i]; | |
205 | if (opt_idx) | |
206 | { | |
207 | int next_opt_idx; | |
208 | for (j = i + 1; j < argc; j++) | |
209 | { | |
210 | next_opt_idx = options [j]; | |
211 | if (next_opt_idx | |
212 | && cancel_option (opt_idx, next_opt_idx, | |
213 | next_opt_idx)) | |
214 | break; | |
215 | } | |
216 | } | |
217 | else | |
218 | goto keep; | |
219 | ||
220 | if (j == argc) | |
221 | { | |
222 | keep: | |
223 | argv [arg_count] = (*argvp) [i]; | |
224 | arg_count++; | |
225 | } | |
226 | } | |
227 | ||
228 | if (arg_count != argc) | |
229 | { | |
230 | *argcp = arg_count; | |
231 | *argvp = argv; | |
807303cf DK |
232 | /* Add NULL-termination. Guaranteed not to overflow because |
233 | arg_count here can only be less than argc. */ | |
234 | argv[arg_count] = 0; | |
14c7833c L |
235 | } |
236 | else | |
237 | { | |
238 | done: | |
239 | free (argv); | |
240 | } | |
241 | ||
242 | free (options); | |
243 | } |