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opts.c (find_opt): Fix to always guarantee a find of a switch with joined parameter.

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* opts.c (find_opt): Fix to always guarantee a find of a
	switch with joined parameter.
	* opts.h (struct cl_option): New member back_chain.
	* opts.sh: Update to calculate and add back_chain member.

From-SVN: r68324
This commit is contained in:
Neil Booth 2003-06-22 09:04:57 +00:00 committed by Neil Booth
parent 0e9e3a8b78
commit 9cd23ed2b4
4 changed files with 95 additions and 71 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2003-06-22 Neil Booth <neil@daikokuya.co.uk>
* opts.c (find_opt): Fix to always guarantee a find of a
switch with joined parameter.
* opts.h (struct cl_option): New member back_chain.
* opts.sh: Update to calculate and add back_chain member.
2003-06-22 Gabriel Dos Reis <gdr@integrable-solutions.net>
* diagnostic.h (output_host_wide_integer): Declare.

130
gcc/opts.c
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@ -131,93 +131,87 @@ static void handle_param (const char *);
static void set_Wextra (int);
/* Perform a binary search to find which option the command-line INPUT
matches. Returns its index in the option array, and N_OPTS on
failure.
matches. Returns its index in the option array, and N_OPTS
(cl_options_count) on failure.
Complications arise since some options can be suffixed with an
argument, and multiple complete matches can occur, e.g. -pedantic
and -pedantic-errors. Also, some options are only accepted by some
languages. If a switch matches for a different language and
doesn't match any alternatives for the true front end, the index of
the matched switch is returned anyway. The caller should check for
this case. */
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, opts.sh 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. */
static size_t
find_opt (const char *input, int lang_mask)
{
size_t md, mn, mx;
size_t opt_len;
size_t result = cl_options_count;
size_t mn, mx, md, opt_len;
size_t match_wrong_lang;
int comp;
mn = 0;
mx = cl_options_count;
while (mx > mn)
/* 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, opt_len);
if (comp < 0)
mx = md;
else if (comp > 0)
mn = md + 1;
else
{
/* The switch matches. It it an exact match? */
if (input[opt_len] == '\0')
return md;
else
{
mn = md + 1;
/* If the switch takes no arguments this is not a proper
match, so we continue the search (e.g. input="stdc++"
match was "stdc"). */
if (!(cl_options[md].flags & CL_JOINED))
continue;
/* Is this switch valid for this front end? */
if (!(cl_options[md].flags & lang_mask))
{
/* If subsequently we don't find a better match,
return this and let the caller report it as a bad
match. */
result = md;
continue;
}
/* Two scenarios remain: we have the switch's argument,
or we match a longer option. This can happen with
-iwithprefix and -withprefixbefore. The longest
possible option match succeeds.
Scan forwards, and return an exact match. Otherwise
return the longest valid option-accepting match (mx).
This loops at most twice with current options. */
mx = md;
for (md = md + 1; md < cl_options_count; md++)
{
opt_len = cl_options[md].opt_len;
comp = strncmp (input, cl_options[md].opt_text, opt_len);
if (comp < 0)
break;
if (comp > 0)
continue;
if (input[opt_len] == '\0')
return md;
if (cl_options[md].flags & lang_mask
&& cl_options[md].flags & CL_JOINED)
mx = md;
}
return mx;
}
}
mn = md;
}
return result;
/* 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. */
do
{
const struct cl_option *opt = &cl_options[mn];
/* Is this switch a prefix of the input? */
if (!strncmp (input, opt->opt_text, opt->opt_len))
{
/* If language is OK, and the match is exact or the switch
takes a joined argument, return it. */
if ((opt->flags & lang_mask)
&& (input[opt->opt_len] == '\0' || (opt->flags & CL_JOINED)))
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;
}
/* If ARG is a non-negative integer made up solely of digits, return its

1
gcc/opts.h
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@ -26,6 +26,7 @@ extern int handle_option (int argc, char **argv, int lang_mask);
struct cl_option
{
const char *opt_text;
unsigned short back_chain;
unsigned char opt_len;
unsigned int flags;
};

28
gcc/opts.sh
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@ -100,21 +100,43 @@ ${AWK} '
print "const unsigned int cl_options_count = N_OPTS;\n" >> c_file
print "const struct cl_option cl_options[] =\n{" >> c_file
for (i = 0; i < n_opts; i++)
back_chain[i] = "N_OPTS";
for (i = 0; i < n_opts; i++) {
# Combine the flags of identical switches. Switches
# appear many times if they are handled by many front
# ends, for example.
while( i + 1 != n_opts && opts[i] == opts[i + 1] ) {
flags[i + 1] = flags[i] " " flags[i + 1];
i++;
}
len = length (opts[i]);
enum = "OPT_" opts[i]
gsub( "[^A-Za-z0-9]", "_", enum)
gsub ("[^A-Za-z0-9]", "_", enum)
# If this switch takes joined arguments, back-chain all
# subsequent switches to it for which it is a prefix. If
# a later switch S is a longer prefix of a switch T, T
# will be back-chained to S in a later iteration of this
# for() loop, which is what we want.
if (flags[i] ~ "Joined") {
for (j = i + 1; j < n_opts; j++) {
if (substr (opts[j], 1, len) != opts[i])
break;
back_chain[j] = enum;
}
}
s = substr(" ", length (opts[i]))
if (i + 1 == n_opts)
comma = ""
printf(" %s,%s/* -%s */\n", enum, s, opts[i]) >> h_file
printf(" { \"%s\", %u, %s }%s\n", opts[i], \
length(opts[i]), switch_flags(flags[i]), comma) >> c_file
printf(" { \"%s\", (unsigned short) %s, %u,\n\t%s }%s\n",
opts[i], back_chain[i], len, switch_flags(flags[i]),
comma) >> c_file
}
print " N_OPTS\n};" >> h_file