text: /* Command line option handling.
     Copyright (C) 2006, 2007, 2008, 2010, 2011 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
  version.
  
  GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  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
  <http://www.gnu.org/licenses/>.  */
  
  #include "config.h"
  #include "system.h"
  #include "intl.h"
  #include "coretypes.h"
  #include "opts.h"
  #include "flags.h"
  #include "diagnostic.h"
  
  static void prune_options (struct cl_decoded_option **, unsigned int *);
  
  /* Perform a binary search to find which option the command-line INPUT
     matches.  Returns its index in the option array, and
     OPT_SPECIAL_unknown 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.  */
  size_t
  find_opt (const char *input, unsigned int lang_mask)
  {
    size_t mn, mn_orig, 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;
        else
  	mn = md;
      }
  
    mn_orig = mn;
  
    /* This is the switch that is the best match but for a different
       front end, or OPT_SPECIAL_unknown if there is no match at all.  */
    match_wrong_lang = OPT_SPECIAL_unknown;
  
    /* 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 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 == OPT_SPECIAL_unknown)
  	    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);
  
    if (match_wrong_lang == OPT_SPECIAL_unknown && input[0] == '-')
      {
        /* Long options, starting "--", may be abbreviated if the
  	 abbreviation is unambiguous.  This only applies to options
  	 not taking a joined argument, and abbreviations of "--option"
  	 are permitted even if there is a variant "--option=".  */
        size_t mnc = mn_orig + 1;
        size_t cmp_len = strlen (input);
        while (mnc < cl_options_count
  	     && strncmp (input, cl_options[mnc].opt_text + 1, cmp_len) == 0)
  	{
  	  /* Option matching this abbreviation.  OK if it is the first
  	     match and that does not take a joined argument, or the
  	     second match, taking a joined argument and with only '='
  	     added to the first match; otherwise considered
  	     ambiguous.  */
  	  if (mnc == mn_orig + 1
  	      && !(cl_options[mnc].flags & CL_JOINED))
  	    match_wrong_lang = mnc;
  	  else if (mnc == mn_orig + 2
  		   && match_wrong_lang == mn_orig + 1
  		   && (cl_options[mnc].flags & CL_JOINED)
  		   && (cl_options[mnc].opt_len
  		       == cl_options[mn_orig + 1].opt_len + 1)
  		   && strncmp (cl_options[mnc].opt_text + 1,
  			       cl_options[mn_orig + 1].opt_text + 1,
  			       cl_options[mn_orig + 1].opt_len) == 0)
  	    ; /* OK, as long as there are no more matches.  */
  	  else
  	    return OPT_SPECIAL_unknown;
  	  mnc++;
  	}
      }
  
    /* Return the best wrong match, or OPT_SPECIAL_unknown if none.  */
    return match_wrong_lang;
  }
  
  /* If ARG is a non-negative integer made up solely of digits, return its
     value, otherwise return -1.  */
  
  int
  integral_argument (const char *arg)
  {
    const char *p = arg;
  
    while (*p && ISDIGIT (*p))
      p++;
  
    if (*p == '\0')
      return atoi (arg);
  
    return -1;
  }
  
  /* Return whether OPTION is OK for the language given by
     LANG_MASK.  */
  static bool
  option_ok_for_language (const struct cl_option *option,
  			unsigned int lang_mask)
  {
    if (!(option->flags & lang_mask))
      return false;
    else if ((option->flags & CL_TARGET)
  	   && (option->flags & (CL_LANG_ALL | CL_DRIVER))
  	   && !(option->flags & (lang_mask & ~CL_COMMON & ~CL_TARGET)))
      /* Complain for target flag language mismatches if any languages
         are specified.  */
      return false;
    return true;
  }
  
  /* Return whether ENUM_ARG is OK for the language given by
     LANG_MASK.  */
  
  static bool
  enum_arg_ok_for_language (const struct cl_enum_arg *enum_arg,
  			  unsigned int lang_mask)
  {
    return (lang_mask & CL_DRIVER) || !(enum_arg->flags & CL_ENUM_DRIVER_ONLY);
  }
  
  /* Look up ARG in ENUM_ARGS for language LANG_MASK, returning true and
     storing the value in *VALUE if found, and returning false without
     modifying *VALUE if not found.  */
  
  static bool
  enum_arg_to_value (const struct cl_enum_arg *enum_args,
  		   const char *arg, int *value, unsigned int lang_mask)
  {
    unsigned int i;
  
    for (i = 0; enum_args[i].arg != NULL; i++)
      if (strcmp (arg, enum_args[i].arg) == 0
  	&& enum_arg_ok_for_language (&enum_args[i], lang_mask))
        {
  	*value = enum_args[i].value;
  	return true;
        }
  
    return false;
  }
  
  /* Look up ARG in the enum used by option OPT_INDEX for language
     LANG_MASK, returning true and storing the value in *VALUE if found,
     and returning false without modifying *VALUE if not found.  */
  
  bool
  opt_enum_arg_to_value (size_t opt_index, const char *arg, int *value,
  		       unsigned int lang_mask)
  {
    const struct cl_option *option = &cl_options[opt_index];
  
    gcc_assert (option->var_type == CLVC_ENUM);
  
    return enum_arg_to_value (cl_enums[option->var_enum].values, arg,
  			    value, lang_mask);
  }
  
  /* Look of VALUE in ENUM_ARGS for language LANG_MASK and store the
     corresponding string in *ARGP, returning true if the found string
     was marked as canonical, false otherwise.  If VALUE is not found
     (which may be the case for uninitialized values if the relevant
     option has not been passed), set *ARGP to NULL and return
     false.  */
  
  bool
  enum_value_to_arg (const struct cl_enum_arg *enum_args,
  		   const char **argp, int value, unsigned int lang_mask)
  {
    unsigned int i;
  
    for (i = 0; enum_args[i].arg != NULL; i++)
      if (enum_args[i].value == value
  	&& (enum_args[i].flags & CL_ENUM_CANONICAL)
  	&& enum_arg_ok_for_language (&enum_args[i], lang_mask))
        {
  	*argp = enum_args[i].arg;
  	return true;
        }
  
    for (i = 0; enum_args[i].arg != NULL; i++)
      if (enum_args[i].value == value
  	&& enum_arg_ok_for_language (&enum_args[i], lang_mask))
        {
  	*argp = enum_args[i].arg;
  	return false;
        }
  
    *argp = NULL;
    return false;
  }
  
  /* Fill in the canonical option part of *DECODED with an option
     described by OPT_INDEX, ARG and VALUE.  */
  
  static void
  generate_canonical_option (size_t opt_index, const char *arg, int value,
  			   struct cl_decoded_option *decoded)
  {
    const struct cl_option *option = &cl_options[opt_index];
    const char *opt_text = option->opt_text;
  
    if (value == 0
        && !option->cl_reject_negative
        && (opt_text[1] == 'W' || opt_text[1] == 'f' || opt_text[1] == 'm'))
      {
        char *t = XNEWVEC (char, option->opt_len + 5);
        t[0] = '-';
        t[1] = opt_text[1];
        t[2] = 'n';
        t[3] = 'o';
        t[4] = '-';
        memcpy (t + 5, opt_text + 2, option->opt_len);
        opt_text = t;
      }
  
    decoded->canonical_option[2] = NULL;
    decoded->canonical_option[3] = NULL;
  
    if (arg)
      {
        if ((option->flags & CL_SEPARATE)
  	  && !option->cl_separate_alias)
  	{
  	  decoded->canonical_option[0] = opt_text;
  	  decoded->canonical_option[1] = arg;
  	  decoded->canonical_option_num_elements = 2;
  	}
        else
  	{
  	  gcc_assert (option->flags & CL_JOINED);
  	  decoded->canonical_option[0] = concat (opt_text, arg, NULL);
  	  decoded->canonical_option[1] = NULL;
  	  decoded->canonical_option_num_elements = 1;
  	  if (opt_text != option->opt_text)
  	    free (CONST_CAST (char *, opt_text));
  	}
      }
    else
      {
        decoded->canonical_option[0] = opt_text;
        decoded->canonical_option[1] = NULL;
        decoded->canonical_option_num_elements = 1;
      }
  }
  
  /* Structure describing mappings from options on the command line to
     options to look up with find_opt.  */
  struct option_map
  {
    /* Prefix of the option on the command line.  */
    const char *opt0;
    /* If two argv elements are considered to be merged into one option,
       prefix for the second element, otherwise NULL.  */
    const char *opt1;
    /* The new prefix to map to.  */
    const char *new_prefix;
    /* Whether at least one character is needed following opt1 or opt0
       for this mapping to be used.  (--optimize= is valid for -O, but
       --warn- is not valid for -W.)  */
    bool another_char_needed;
    /* Whether the original option is a negated form of the option
       resulting from this map.  */
    bool negated;
  };
  static const struct option_map option_map[] =
    {
      { "-Wno-", NULL, "-W", false, true },
      { "-fno-", NULL, "-f", false, true },
      { "-mno-", NULL, "-m", false, true },
      { "--debug=", NULL, "-g", false, false },
      { "--machine-", NULL, "-m", true, false },
      { "--machine-no-", NULL, "-m", false, true },
      { "--machine=", NULL, "-m", false, false },
      { "--machine=no-", NULL, "-m", false, true },
      { "--machine", "", "-m", false, false },
      { "--machine", "no-", "-m", false, true },
      { "--optimize=", NULL, "-O", false, false },
      { "--std=", NULL, "-std=", false, false },
      { "--std", "", "-std=", false, false },
      { "--warn-", NULL, "-W", true, false },
      { "--warn-no-", NULL, "-W", false, true },
      { "--", NULL, "-f", true, false },
      { "--no-", NULL, "-f", false, true }
    };
  
  /* Decode the switch beginning at ARGV for the language indicated by
     LANG_MASK (including CL_COMMON and CL_TARGET if applicable), into
     the structure *DECODED.  Returns the number of switches
     consumed.  */
  
  static unsigned int
  decode_cmdline_option (const char **argv, unsigned int lang_mask,
  		       struct cl_decoded_option *decoded)
  {
    size_t opt_index;
    const char *arg = 0;
    int value = 1;
    unsigned int result = 1, i, extra_args, separate_args = 0;
    int adjust_len = 0;
    size_t total_len;
    char *p;
    const struct cl_option *option;
    int errors = 0;
    const char *warn_message = NULL;
    bool separate_arg_flag;
    bool joined_arg_flag;
    bool have_separate_arg = false;
  
    extra_args = 0;
  
    opt_index = find_opt (argv[0] + 1, lang_mask);
    i = 0;
    while (opt_index == OPT_SPECIAL_unknown
  	 && i < ARRAY_SIZE (option_map))
      {
        const char *opt0 = option_map[i].opt0;
        const char *opt1 = option_map[i].opt1;
        const char *new_prefix = option_map[i].new_prefix;
        bool another_char_needed = option_map[i].another_char_needed;
        size_t opt0_len = strlen (opt0);
        size_t opt1_len = (opt1 == NULL ? 0 : strlen (opt1));
        size_t optn_len = (opt1 == NULL ? opt0_len : opt1_len);
        size_t new_prefix_len = strlen (new_prefix);
  
        extra_args = (opt1 == NULL ? 0 : 1);
        value = !option_map[i].negated;
  
        if (strncmp (argv[0], opt0, opt0_len) == 0
  	  && (opt1 == NULL
  	      || (argv[1] != NULL && strncmp (argv[1], opt1, opt1_len) == 0))
  	  && (!another_char_needed
  	      || argv[extra_args][optn_len] != 0))
  	{
  	  size_t arglen = strlen (argv[extra_args]);
  	  char *dup;
  
  	  adjust_len = (int) optn_len - (int) new_prefix_len;
  	  dup = XNEWVEC (char, arglen + 1 - adjust_len);
  	  memcpy (dup, new_prefix, new_prefix_len);
  	  memcpy (dup + new_prefix_len, argv[extra_args] + optn_len,
  		  arglen - optn_len + 1);
  	  opt_index = find_opt (dup + 1, lang_mask);
  	  free (dup);
  	}
        i++;
      }
  
    if (opt_index == OPT_SPECIAL_unknown)
      {
        arg = argv[0];
        extra_args = 0;
        value = 1;
        goto done;
      }
  
    option = &cl_options[opt_index];
  
    /* Reject negative form of switches that don't take negatives as
       unrecognized.  */
    if (!value && option->cl_reject_negative)
      {
        opt_index = OPT_SPECIAL_unknown;
        errors |= CL_ERR_NEGATIVE;
        arg = argv[0];
        goto done;
      }
  
    result = extra_args + 1;
    warn_message = option->warn_message;
  
    /* Check to see if the option is disabled for this configuration.  */
    if (option->cl_disabled)
      errors |= CL_ERR_DISABLED;
  
    /* Determine whether there may be a separate argument based on
       whether this option is being processed for the driver, and, if
       so, how many such arguments.  */
    separate_arg_flag = ((option->flags & CL_SEPARATE)
  		       && !(option->cl_no_driver_arg
  			    && (lang_mask & CL_DRIVER)));
    separate_args = (separate_arg_flag
  		   ? option->cl_separate_nargs + 1
  		   : 0);
    joined_arg_flag = (option->flags & CL_JOINED) != 0;
  
    /* Sort out any argument the switch takes.  */
    if (joined_arg_flag)
      {
        /* Have arg point to the original switch.  This is because
  	 some code, such as disable_builtin_function, expects its
  	 argument to be persistent until the program exits.  */
        arg = argv[extra_args] + cl_options[opt_index].opt_len + 1 + adjust_len;
  
        if (*arg == '\0' && !option->cl_missing_ok)
  	{
  	  if (separate_arg_flag)
  	    {
  	      arg = argv[extra_args + 1];
  	      result = extra_args + 2;
  	      if (arg == NULL)
  		result = extra_args + 1;
  	      else
  		have_separate_arg = true;
  	    }
  	  else
  	    /* Missing argument.  */
  	    arg = NULL;
  	}
      }
    else if (separate_arg_flag)
      {
        arg = argv[extra_args + 1];
        for (i = 0; i < separate_args; i++)
  	if (argv[extra_args + 1 + i] == NULL)
  	  {
  	    errors |= CL_ERR_MISSING_ARG;
  	    break;
  	  }
        result = extra_args + 1 + i;
        if (arg != NULL)
  	have_separate_arg = true;
      }
  
    if (arg == NULL && (separate_arg_flag || joined_arg_flag))
      errors |= CL_ERR_MISSING_ARG;
  
    /* Is this option an alias (or an ignored option, marked as an alias
       of OPT_SPECIAL_ignore)?  */
    if (option->alias_target != N_OPTS
        && (!option->cl_separate_alias || have_separate_arg))
      {
        size_t new_opt_index = option->alias_target;
  
        if (new_opt_index == OPT_SPECIAL_ignore)
  	{
  	  gcc_assert (option->alias_arg == NULL);
  	  gcc_assert (option->neg_alias_arg == NULL);
  	  opt_index = new_opt_index;
  	  arg = NULL;
  	  value = 1;
  	}
        else
  	{
  	  const struct cl_option *new_option = &cl_options[new_opt_index];
  
  	  /* The new option must not be an alias itself.  */
  	  gcc_assert (new_option->alias_target == N_OPTS
  		      || new_option->cl_separate_alias);
  
  	  if (option->neg_alias_arg)
  	    {
  	      gcc_assert (option->alias_arg != NULL);
  	      gcc_assert (arg == NULL);
  	      gcc_assert (!option->cl_negative_alias);
  	      if (value)
  		arg = option->alias_arg;
  	      else
  		arg = option->neg_alias_arg;
  	      value = 1;
  	    }
  	  else if (option->alias_arg)
  	    {
  	      gcc_assert (value == 1);
  	      gcc_assert (arg == NULL);
  	      gcc_assert (!option->cl_negative_alias);
  	      arg = option->alias_arg;
  	    }
  
  	  if (option->cl_negative_alias)
  	    value = !value;
  
  	  opt_index = new_opt_index;
  	  option = new_option;
  
  	  if (value == 0)
  	    gcc_assert (!option->cl_reject_negative);
  
  	  /* Recompute what arguments are allowed.  */
  	  separate_arg_flag = ((option->flags & CL_SEPARATE)
  			       && !(option->cl_no_driver_arg
  				    && (lang_mask & CL_DRIVER)));
  	  joined_arg_flag = (option->flags & CL_JOINED) != 0;
  
  	  if (separate_args > 1 || option->cl_separate_nargs)
  	    gcc_assert (separate_args
  			== (unsigned int) option->cl_separate_nargs + 1);
  
  	  if (!(errors & CL_ERR_MISSING_ARG))
  	    {
  	      if (separate_arg_flag || joined_arg_flag)
  		{
  		  if (option->cl_missing_ok && arg == NULL)
  		    arg = "";
  		  gcc_assert (arg != NULL);
  		}
  	      else
  		gcc_assert (arg == NULL);
  	    }
  
  	  /* Recheck for warnings and disabled options.  */
  	  if (option->warn_message)
  	    {
  	      gcc_assert (warn_message == NULL);
  	      warn_message = option->warn_message;
  	    }
  	  if (option->cl_disabled)
  	    errors |= CL_ERR_DISABLED;
  	}
      }
  
    /* Check if this is a switch for a different front end.  */
    if (!option_ok_for_language (option, lang_mask))
      errors |= CL_ERR_WRONG_LANG;
  
    /* Convert the argument to lowercase if appropriate.  */
    if (arg && option->cl_tolower)
      {
        size_t j;
        size_t len = strlen (arg);
        char *arg_lower = XNEWVEC (char, len + 1);
  
        for (j = 0; j < len; j++)
  	arg_lower[j] = TOLOWER ((unsigned char) arg[j]);
        arg_lower[len] = 0;
        arg = arg_lower;
      }
  
    /* If the switch takes an integer, convert it.  */
    if (arg && option->cl_uinteger)
      {
        value = integral_argument (arg);
        if (value == -1)
  	errors |= CL_ERR_UINT_ARG;
      }
  
    /* If the switch takes an enumerated argument, convert it.  */
    if (arg && (option->var_type == CLVC_ENUM))
      {
        const struct cl_enum *e = &cl_enums[option->var_enum];
  
        gcc_assert (value == 1);
        if (enum_arg_to_value (e->values, arg, &value, lang_mask))
  	{
  	  const char *carg = NULL;
  
  	  if (enum_value_to_arg (e->values, &carg, value, lang_mask))
  	    arg = carg;
  	  gcc_assert (carg != NULL);
  	}
        else
  	errors |= CL_ERR_ENUM_ARG;
      }
  
   done:
    decoded->opt_index = opt_index;
    decoded->arg = arg;
    decoded->value = value;
    decoded->errors = errors;
    decoded->warn_message = warn_message;
  
    if (opt_index == OPT_SPECIAL_unknown)
      gcc_assert (result == 1);
  
    gcc_assert (result >= 1 && result <= ARRAY_SIZE (decoded->canonical_option));
    decoded->canonical_option_num_elements = result;
    total_len = 0;
    for (i = 0; i < ARRAY_SIZE (decoded->canonical_option); i++)
      {
        if (i < result)
  	{
  	  size_t len;
  	  if (opt_index == OPT_SPECIAL_unknown)
  	    decoded->canonical_option[i] = argv[i];
  	  else
  	    decoded->canonical_option[i] = NULL;
  	  len = strlen (argv[i]);
  	  /* If the argument is an empty string, we will print it as "" in
  	     orig_option_with_args_text.  */
  	  total_len += (len != 0 ? len : 2) + 1;
  	}
        else
  	decoded->canonical_option[i] = NULL;
      }
    if (opt_index != OPT_SPECIAL_unknown && opt_index != OPT_SPECIAL_ignore)
      {
        generate_canonical_option (opt_index, arg, value, decoded);
        if (separate_args > 1)
  	{
  	  for (i = 0; i < separate_args; i++)
  	    {
  	      if (argv[extra_args + 1 + i] == NULL)
  		  break;
  	      else
  		decoded->canonical_option[1 + i] = argv[extra_args + 1 + i];
  	    }
  	  gcc_assert (result == 1 + i);
  	  decoded->canonical_option_num_elements = result;
  	}
      }
    decoded->orig_option_with_args_text = p = XNEWVEC (char, total_len);
    for (i = 0; i < result; i++)
      {
        size_t len = strlen (argv[i]);
  
        /* Print the empty string verbally.  */
        if (len == 0)
  	{
  	  *p++ = '"';
  	  *p++ = '"';
  	}
        else
  	memcpy (p, argv[i], len);
        p += len;
        if (i == result - 1)
  	*p++ = 0;
        else
  	*p++ = ' ';
      }
  
    return result;
  }
  
  /* Decode command-line options (ARGC and ARGV being the arguments of
     main) into an array, setting *DECODED_OPTIONS to a pointer to that
     array and *DECODED_OPTIONS_COUNT to the number of entries in the
     array.  The first entry in the array is always one for the program
     name (OPT_SPECIAL_program_name).  LANG_MASK indicates the language
     flags applicable for decoding (including CL_COMMON and CL_TARGET if
     those options should be considered applicable).  Do not produce any
     diagnostics or set state outside of these variables.  */
  
  void
  decode_cmdline_options_to_array (unsigned int argc, const char **argv, 
  				 unsigned int lang_mask,
  				 struct cl_decoded_option **decoded_options,
  				 unsigned int *decoded_options_count)
  {
    unsigned int n, i;
    struct cl_decoded_option *opt_array;
    unsigned int num_decoded_options;
  
    opt_array = XNEWVEC (struct cl_decoded_option, argc);
  
    opt_array[0].opt_index = OPT_SPECIAL_program_name;
    opt_array[0].warn_message = NULL;
    opt_array[0].arg = argv[0];
    opt_array[0].orig_option_with_args_text = argv[0];
    opt_array[0].canonical_option_num_elements = 1;
    opt_array[0].canonical_option[0] = argv[0];
    opt_array[0].canonical_option[1] = NULL;
    opt_array[0].canonical_option[2] = NULL;
    opt_array[0].canonical_option[3] = NULL;
    opt_array[0].value = 1;
    opt_array[0].errors = 0;
    num_decoded_options = 1;
  
    for (i = 1; i < argc; i += n)
      {
        const char *opt = argv[i];
  
        /* Interpret "-" or a non-switch as a file name.  */
        if (opt[0] != '-' || opt[1] == '\0')
  	{
  	  generate_option_input_file (opt, &opt_array[num_decoded_options]);
  	  num_decoded_options++;
  	  n = 1;
  	  continue;
  	}
  
        n = decode_cmdline_option (argv + i, lang_mask,
  				 &opt_array[num_decoded_options]);
        num_decoded_options++;
      }
  
    *decoded_options = opt_array;
    *decoded_options_count = num_decoded_options;
    prune_options (decoded_options, decoded_options_count);
  }
  
  /* 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,
  			  orig_next_opt_idx);
  
    return false;
  }
  
  /* Filter out options canceled by the ones after them.  */
  
  static void
  prune_options (struct cl_decoded_option **decoded_options,
  	       unsigned int *decoded_options_count)
  {
    unsigned int old_decoded_options_count = *decoded_options_count;
    struct cl_decoded_option *old_decoded_options = *decoded_options;
    unsigned int new_decoded_options_count;
    struct cl_decoded_option *new_decoded_options
      = XNEWVEC (struct cl_decoded_option, old_decoded_options_count);
    unsigned int i;
    const struct cl_option *option;
  
    /* Remove arguments which are negated by others after them.  */
    new_decoded_options_count = 0;
    for (i = 0; i < old_decoded_options_count; i++)
      {
        unsigned int j, opt_idx, next_opt_idx;
  
        if (old_decoded_options[i].errors & ~CL_ERR_WRONG_LANG)
  	goto keep;
  
        opt_idx = old_decoded_options[i].opt_index;
        switch (opt_idx)
  	{
  	case OPT_SPECIAL_unknown:
  	case OPT_SPECIAL_ignore:
  	case OPT_SPECIAL_program_name:
  	case OPT_SPECIAL_input_file:
  	  goto keep;
  
  	default:
  	  gcc_assert (opt_idx < cl_options_count);
  	  option = &cl_options[opt_idx];
  	  if (option->neg_index < 0)
  	    goto keep;
  
  	  /* Skip joined switches.  */
  	  if ((option->flags & CL_JOINED))
  	    goto keep;
  
  	  for (j = i + 1; j < old_decoded_options_count; j++)
  	    {
  	      if (old_decoded_options[j].errors & ~CL_ERR_WRONG_LANG)
  		continue;
  	      next_opt_idx = old_decoded_options[j].opt_index;
  	      if (next_opt_idx >= cl_options_count)
  		continue;
  	      if (cl_options[next_opt_idx].neg_index < 0)
  		continue;
  	      if ((cl_options[next_opt_idx].flags & CL_JOINED))
  		  continue;
  	      if (cancel_option (opt_idx, next_opt_idx, next_opt_idx))
  		break;
  	    }
  	  if (j == old_decoded_options_count)
  	    {
  keep:
  	      new_decoded_options[new_decoded_options_count]
  		= old_decoded_options[i];
  	      new_decoded_options_count++;
  	    }
  	  break;
  	}
      }
  
    free (old_decoded_options);
    new_decoded_options = XRESIZEVEC (struct cl_decoded_option,
  				    new_decoded_options,
  				    new_decoded_options_count);
    *decoded_options = new_decoded_options;
    *decoded_options_count = new_decoded_options_count;
  }
  
  /* Handle option DECODED for the language indicated by LANG_MASK,
     using the handlers in HANDLERS and setting fields in OPTS and
     OPTS_SET.  KIND is the diagnostic_t if this is a diagnostics
     option, DK_UNSPECIFIED otherwise, and LOC is the location of the
     option for options from the source file, UNKNOWN_LOCATION
     otherwise.  GENERATED_P is true for an option generated as part of
     processing another option or otherwise generated internally, false
     for one explicitly passed by the user.  Returns false if the switch
     was invalid.  DC is the diagnostic context for options affecting
     diagnostics state, or NULL.  */
  
  static bool
  handle_option (struct gcc_options *opts,
  	       struct gcc_options *opts_set,
  	       const struct cl_decoded_option *decoded,
  	       unsigned int lang_mask, int kind, location_t loc,
  	       const struct cl_option_handlers *handlers,
  	       bool generated_p, diagnostic_context *dc)
  {
    size_t opt_index = decoded->opt_index;
    const char *arg = decoded->arg;
    int value = decoded->value;
    const struct cl_option *option = &cl_options[opt_index];
    void *flag_var = option_flag_var (opt_index, opts);
    size_t i;
  
    if (flag_var)
      set_option (opts, (generated_p ? NULL : opts_set),
  		opt_index, value, arg, kind, loc, dc);
  
    for (i = 0; i < handlers->num_handlers; i++)
      if (option->flags & handlers->handlers[i].mask)
        {
  	if (!handlers->handlers[i].handler (opts, opts_set, decoded,
  					    lang_mask, kind, loc,
  					    handlers, dc))
  	  return false;
        }
    
    return true;
  }
  
  /* Like handle_option, but OPT_INDEX, ARG and VALUE describe the
     option instead of DECODED.  This is used for callbacks when one
     option implies another instead of an option being decoded from the
     command line.  */
  
  bool
  handle_generated_option (struct gcc_options *opts,
  			 struct gcc_options *opts_set,
  			 size_t opt_index, const char *arg, int value,
  			 unsigned int lang_mask, int kind, location_t loc,
  			 const struct cl_option_handlers *handlers,
  			 diagnostic_context *dc)
  {
    struct cl_decoded_option decoded;
  
    generate_option (opt_index, arg, value, lang_mask, &decoded);
    return handle_option (opts, opts_set, &decoded, lang_mask, kind, loc,
  			handlers, true, dc);
  }
  
  /* Fill in *DECODED with an option described by OPT_INDEX, ARG and
     VALUE for a front end using LANG_MASK.  This is used when the
     compiler generates options internally.  */
  
  void
  generate_option (size_t opt_index, const char *arg, int value,
  		 unsigned int lang_mask, struct cl_decoded_option *decoded)
  {
    const struct cl_option *option = &cl_options[opt_index];
  
    decoded->opt_index = opt_index;
    decoded->warn_message = NULL;
    decoded->arg = arg;
    decoded->value = value;
    decoded->errors = (option_ok_for_language (option, lang_mask)
  		     ? 0
  		     : CL_ERR_WRONG_LANG);
  
    generate_canonical_option (opt_index, arg, value, decoded);
    switch (decoded->canonical_option_num_elements)
      {
      case 1:
        decoded->orig_option_with_args_text = decoded->canonical_option[0];
        break;
  
      case 2:
        decoded->orig_option_with_args_text
  	= concat (decoded->canonical_option[0], " ",
  		  decoded->canonical_option[1], NULL);
        break;
  
      default:
        gcc_unreachable ();
      }
  }
  
  /* Fill in *DECODED with an option for input file FILE.  */
  
  void
  generate_option_input_file (const char *file,
  			    struct cl_decoded_option *decoded)
  {
    decoded->opt_index = OPT_SPECIAL_input_file;
    decoded->warn_message = NULL;
    decoded->arg = file;
    decoded->orig_option_with_args_text = file;
    decoded->canonical_option_num_elements = 1;
    decoded->canonical_option[0] = file;
    decoded->canonical_option[1] = NULL;
    decoded->canonical_option[2] = NULL;
    decoded->canonical_option[3] = NULL;
    decoded->value = 1;
    decoded->errors = 0;
  }
  
  /* Handle the switch DECODED (location LOC) for the language indicated
     by LANG_MASK, using the handlers in *HANDLERS and setting fields in
     OPTS and OPTS_SET and using diagnostic context DC (if not NULL) for
     diagnostic options.  */
  
  void
  read_cmdline_option (struct gcc_options *opts,
  		     struct gcc_options *opts_set,
  		     struct cl_decoded_option *decoded,
  		     location_t loc,
  		     unsigned int lang_mask,
  		     const struct cl_option_handlers *handlers,
  		     diagnostic_context *dc)
  {
    const struct cl_option *option;
    const char *opt = decoded->orig_option_with_args_text;
  
    if (decoded->warn_message)
      warning_at (loc, 0, decoded->warn_message, opt);
  
    if (decoded->opt_index == OPT_SPECIAL_unknown)
      {
        if (handlers->unknown_option_callback (decoded))
  	error_at (loc, "unrecognized command line option %qs", decoded->arg);
        return;
      }
  
    if (decoded->opt_index == OPT_SPECIAL_ignore)
      return;
  
    option = &cl_options[decoded->opt_index];
  
    if (decoded->errors & CL_ERR_DISABLED)
      {
        error_at (loc, "command line option %qs"
  		" is not supported by this configuration", opt);
        return;
      }
  
    if (decoded->errors & CL_ERR_MISSING_ARG)
      {
        if (option->missing_argument_error)
  	error_at (loc, option->missing_argument_error, opt);
        else
  	error_at (loc, "missing argument to %qs", opt);
        return;
      }
  
    if (decoded->errors & CL_ERR_UINT_ARG)
      {
        error_at (loc, "argument to %qs should be a non-negative integer",
  		option->opt_text);
        return;
      }
  
    if (decoded->errors & CL_ERR_ENUM_ARG)
      {
        const struct cl_enum *e = &cl_enums[option->var_enum];
        unsigned int i;
        size_t len;
        char *s, *p;
  
        if (e->unknown_error)
  	error_at (loc, e->unknown_error, decoded->arg);
        else
  	error_at (loc, "unrecognized argument in option %qs", opt);
  
        len = 0;
        for (i = 0; e->values[i].arg != NULL; i++)
  	len += strlen (e->values[i].arg) + 1;
  
        s = XALLOCAVEC (char, len);
        p = s;
        for (i = 0; e->values[i].arg != NULL; i++)
  	{
  	  size_t arglen = strlen (e->values[i].arg);
  	  memcpy (p, e->values[i].arg, arglen);
  	  p[arglen] = ' ';
  	  p += arglen + 1;
  	}
        p[-1] = 0;
        inform (loc, "valid arguments to %qs are: %s", option->opt_text, s);
        return;
      }
  
    if (decoded->errors & CL_ERR_WRONG_LANG)
      {
        handlers->wrong_lang_callback (decoded, lang_mask);
        return;
      }
  
    gcc_assert (!decoded->errors);
  
    if (!handle_option (opts, opts_set, decoded, lang_mask, DK_UNSPECIFIED,
  		      loc, handlers, false, dc))
      error_at (loc, "unrecognized command line option %qs", opt);
  }
  
  /* Set any field in OPTS, and OPTS_SET if not NULL, for option
     OPT_INDEX according to VALUE and ARG, diagnostic kind KIND,
     location LOC, using diagnostic context DC if not NULL for
     diagnostic classification.  */
  
  void
  set_option (struct gcc_options *opts, struct gcc_options *opts_set,
  	    int opt_index, int value, const char *arg, int kind,
  	    location_t loc, diagnostic_context *dc)
  {
    const struct cl_option *option = &cl_options[opt_index];
    void *flag_var = option_flag_var (opt_index, opts);
    void *set_flag_var = NULL;
  
    if (!flag_var)
      return;
  
    if (opts_set != NULL)
      set_flag_var = option_flag_var (opt_index, opts_set);
  
    switch (option->var_type)
      {
      case CLVC_BOOLEAN:
  	*(int *) flag_var = value;
  	if (set_flag_var)
  	  *(int *) set_flag_var = 1;
  	break;
  
      case CLVC_EQUAL:
  	if (option->cl_host_wide_int) 
  	  *(HOST_WIDE_INT *) flag_var = (value
  					 ? option->var_value
  					 : !option->var_value);
  	else
  	  *(int *) flag_var = (value
  			       ? option->var_value
  			       : !option->var_value);
  	if (set_flag_var)
  	  *(int *) set_flag_var = 1;
  	break;
  
      case CLVC_BIT_CLEAR:
      case CLVC_BIT_SET:
  	if ((value != 0) == (option->var_type == CLVC_BIT_SET))
  	  {
  	    if (option->cl_host_wide_int) 
  	      *(HOST_WIDE_INT *) flag_var |= option->var_value;
  	    else 
  	      *(int *) flag_var |= option->var_value;
  	  }
  	else
  	  {
  	    if (option->cl_host_wide_int) 
  	      *(HOST_WIDE_INT *) flag_var &= ~option->var_value;
  	    else 
  	      *(int *) flag_var &= ~option->var_value;
  	  }
  	if (set_flag_var)
  	  {
  	    if (option->cl_host_wide_int) 
  	      *(HOST_WIDE_INT *) set_flag_var |= option->var_value;
  	    else
  	      *(int *) set_flag_var |= option->var_value;
  	  }
  	break;
  
      case CLVC_STRING:
  	*(const char **) flag_var = arg;
  	if (set_flag_var)
  	  *(const char **) set_flag_var = "";
  	break;
  
      case CLVC_ENUM:
        {
  	const struct cl_enum *e = &cl_enums[option->var_enum];
  
  	e->set (flag_var, value);
  	if (set_flag_var)
  	  e->set (set_flag_var, 1);
        }
        break;
  
      case CLVC_DEFER:
  	{
  	  VEC(cl_deferred_option,heap) *vec
  	    = (VEC(cl_deferred_option,heap) *) *(void **) flag_var;
  	  cl_deferred_option *p;
  
  	  p = VEC_safe_push (cl_deferred_option, heap, vec, NULL);
  	  p->opt_index = opt_index;
  	  p->arg = arg;
  	  p->value = value;
  	  *(void **) flag_var = vec;
  	  if (set_flag_var)
  	    *(void **) set_flag_var = vec;
  	}
  	break;
      }
  
    if ((diagnostic_t) kind != DK_UNSPECIFIED
        && dc != NULL)
      diagnostic_classify_diagnostic (dc, opt_index, (diagnostic_t) kind, loc);
  }
  
  /* Return the address of the flag variable for option OPT_INDEX in
     options structure OPTS, or NULL if there is no flag variable.  */
  
  void *
  option_flag_var (int opt_index, struct gcc_options *opts)
  {
    const struct cl_option *option = &cl_options[opt_index];
  
    if (option->flag_var_offset == (unsigned short) -1)
      return NULL;
    return (void *)(((char *) opts) + option->flag_var_offset);
  }
  
  /* Return 1 if option OPT_IDX is enabled in OPTS, 0 if it is disabled,
     or -1 if it isn't a simple on-off switch.  */
  
  int
  option_enabled (int opt_idx, void *opts)
  {
    const struct cl_option *option = &(cl_options[opt_idx]);
    struct gcc_options *optsg = (struct gcc_options *) opts;
    void *flag_var = option_flag_var (opt_idx, optsg);
  
    if (flag_var)
      switch (option->var_type)
        {
        case CLVC_BOOLEAN:
  	return *(int *) flag_var != 0;
  
        case CLVC_EQUAL:
  	if (option->cl_host_wide_int) 
  	  return *(HOST_WIDE_INT *) flag_var == option->var_value;
  	else
  	  return *(int *) flag_var == option->var_value;
  
        case CLVC_BIT_CLEAR:
  	if (option->cl_host_wide_int) 
  	  return (*(HOST_WIDE_INT *) flag_var & option->var_value) == 0;
  	else
  	  return (*(int *) flag_var & option->var_value) == 0;
  
        case CLVC_BIT_SET:
  	if (option->cl_host_wide_int) 
  	  return (*(HOST_WIDE_INT *) flag_var & option->var_value) != 0;
  	else 
  	  return (*(int *) flag_var & option->var_value) != 0;
  
        case CLVC_STRING:
        case CLVC_ENUM:
        case CLVC_DEFER:
  	break;
        }
    return -1;
  }
  
  /* Fill STATE with the current state of option OPTION in OPTS.  Return
     true if there is some state to store.  */
  
  bool
  get_option_state (struct gcc_options *opts, int option,
  		  struct cl_option_state *state)
  {
    void *flag_var = option_flag_var (option, opts);
  
    if (flag_var == 0)
      return false;
  
    switch (cl_options[option].var_type)
      {
      case CLVC_BOOLEAN:
      case CLVC_EQUAL:
        state->data = flag_var;
        state->size = (cl_options[option].cl_host_wide_int
  		     ? sizeof (HOST_WIDE_INT)
  		     : sizeof (int));
        break;
  
      case CLVC_BIT_CLEAR:
      case CLVC_BIT_SET:
        state->ch = option_enabled (option, opts);
        state->data = &state->ch;
        state->size = 1;
        break;
  
      case CLVC_STRING:
        state->data = *(const char **) flag_var;
        if (state->data == 0)
  	state->data = "";
        state->size = strlen ((const char *) state->data) + 1;
        break;
  
      case CLVC_ENUM:
        state->data = flag_var;
        state->size = cl_enums[cl_options[option].var_enum].var_size;
        break;
  
      case CLVC_DEFER:
        return false;
      }
    return true;
  }
  
  /* Set a warning option OPT_INDEX (language mask LANG_MASK, option
     handlers HANDLERS) to have diagnostic kind KIND for option
     structures OPTS and OPTS_SET and diagnostic context DC (possibly
     NULL), at location LOC (UNKNOWN_LOCATION for -Werror=).  If IMPLY,
     the warning option in question is implied at this point.  This is
     used by -Werror= and #pragma GCC diagnostic.  */
  
  void
  control_warning_option (unsigned int opt_index, int kind, bool imply,
  			location_t loc, unsigned int lang_mask,
  			const struct cl_option_handlers *handlers,
  			struct gcc_options *opts,
  			struct gcc_options *opts_set,
  			diagnostic_context *dc)
  {
    if (cl_options[opt_index].alias_target != N_OPTS)
      opt_index = cl_options[opt_index].alias_target;
    if (opt_index == OPT_SPECIAL_ignore)
      return;
    if (dc)
      diagnostic_classify_diagnostic (dc, opt_index, (diagnostic_t) kind, loc);
    if (imply)
      {
        /* -Werror=foo implies -Wfoo.  */
        if (cl_options[opt_index].var_type == CLVC_BOOLEAN)
  	handle_generated_option (opts, opts_set,
  				 opt_index, NULL, 1, lang_mask,
  				 kind, loc, handlers, dc);
      }
  }
  