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/* Command line option handling.
Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<>. */
#include "config.h"
#include "system.h"
#include "intl.h"
#include "coretypes.h"
#include "opts.h"
/* Perform a binary search to find which option the command-line INPUT
matches. Returns its index in the option array, and N_OPTS
(cl_options_count) on failure.
This routine is quite subtle. A normal binary search is not good
enough because some options can be suffixed with an argument, and
multiple sub-matches can occur, e.g. input of "-pedantic" matching
the initial substring of "-pedantic-errors".
A more complicated example is -gstabs. It should match "-g" with
an argument of "stabs". Suppose, however, that the number and list
of switches are such that the binary search tests "-gen-decls"
before having tested "-g". This doesn't match, and as "-gen-decls"
is less than "-gstabs", it will become the lower bound of the
binary search range, and "-g" will never be seen. To resolve this
issue, 'optc-gen.awk' makes "-gen-decls" point, via the back_chain member,
to "-g" so that failed searches that end between "-gen-decls" and
the lexicographically subsequent switch know to go back and see if
"-g" causes a match (which it does in this example).
This search is done in such a way that the longest match for the
front end in question wins. If there is no match for the current
front end, the longest match for a different front end is returned
(or N_OPTS if none) and the caller emits an error message. */
find_opt (const char *input, int lang_mask)
size_t mn, mx, md, opt_len;
size_t match_wrong_lang;
int comp;
mn = 0;
mx = cl_options_count;
/* Find mn such this lexicographical inequality holds:
cl_options[mn] <= input < cl_options[mn + 1]. */
while (mx - mn > 1)
md = (mn + mx) / 2;
opt_len = cl_options[md].opt_len;
comp = strncmp (input, cl_options[md].opt_text + 1, opt_len);
if (comp < 0)
mx = md;
mn = md;
/* This is the switch that is the best match but for a different
front end, or cl_options_count if there is no match at all. */
match_wrong_lang = cl_options_count;
/* Backtrace the chain of possible matches, returning the longest
one, if any, that fits best. With current GCC switches, this
loop executes at most twice. */
const struct cl_option *opt = &cl_options[mn];
/* Is the input either an exact match or a prefix that takes a
joined argument? */
if (!strncmp (input, opt->opt_text + 1, opt->opt_len)
&& (input[opt->opt_len] == '\0' || (opt->flags & CL_JOINED)))
/* If language is OK, return it. */
if (opt->flags & lang_mask)
return mn;
/* If we haven't remembered a prior match, remember this
one. Any prior match is necessarily better. */
if (match_wrong_lang == cl_options_count)
match_wrong_lang = mn;
/* Try the next possibility. This is cl_options_count if there
are no more. */
mn = opt->back_chain;
while (mn != cl_options_count);
/* Return the best wrong match, or cl_options_count if none. */
return match_wrong_lang;
/* Return true if NEXT_OPT_IDX cancels OPT_IDX. Return false if the
next one is the same as ORIG_NEXT_OPT_IDX. */
static bool
cancel_option (int opt_idx, int next_opt_idx, int orig_next_opt_idx)
/* An option can be canceled by the same option or an option with
Negative. */
if (cl_options [next_opt_idx].neg_index == opt_idx)
return true;
if (cl_options [next_opt_idx].neg_index != orig_next_opt_idx)
return cancel_option (opt_idx, cl_options [next_opt_idx].neg_index,
return false;
/* Filter out options canceled by the ones after them. */
prune_options (int *argcp, char ***argvp)
int argc = *argcp;
int *options = XNEWVEC (int, argc);
char **argv = XNEWVEC (char *, argc);
int i, arg_count, need_prune = 0;
const struct cl_option *option;
size_t opt_index;
/* Scan all arguments. */
for (i = 1; i < argc; i++)
int value = 1;
const char *opt = (*argvp) [i];
opt_index = find_opt (opt + 1, -1);
if (opt_index == cl_options_count
&& (opt[1] == 'W' || opt[1] == 'f' || opt[1] == 'm')
&& opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-')
char *dup;
/* Drop the "no-" from negative switches. */
size_t len = strlen (opt) - 3;
dup = XNEWVEC (char, len + 1);
dup[0] = '-';
dup[1] = opt[1];
memcpy (dup + 2, opt + 5, len - 2 + 1);
opt = dup;
value = 0;
opt_index = find_opt (opt + 1, -1);
free (dup);
if (opt_index == cl_options_count)
options [i] = 0;
option = &cl_options[opt_index];
if (option->neg_index < 0)
goto cont;
/* Skip joined switches. */
if ((option->flags & CL_JOINED))
goto cont;
/* Reject negative form of switches that don't take negatives as
unrecognized. */
if (!value && (option->flags & CL_REJECT_NEGATIVE))
goto cont;
options [i] = (int) opt_index;
need_prune |= options [i];
if (!need_prune)
goto done;
/* Remove arguments which are negated by others after them. */
argv [0] = (*argvp) [0];
arg_count = 1;
for (i = 1; i < argc; i++)
int j, opt_idx;
opt_idx = options [i];
if (opt_idx)
int next_opt_idx;
for (j = i + 1; j < argc; j++)
next_opt_idx = options [j];
if (next_opt_idx
&& cancel_option (opt_idx, next_opt_idx,
goto keep;
if (j == argc)
argv [arg_count] = (*argvp) [i];
if (arg_count != argc)
*argcp = arg_count;
*argvp = argv;
free (argv);
free (options);