2007-02-20 Manuel Lopez-Ibanez <manu@gcc.gnu.org>

[official-gcc.git] / gcc / opts.c

/* Command line option handling.
   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007
   Free Software Foundation, Inc.
   Contributed by Neil Booth.

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 2, 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 COPYING.  If not, write to the Free
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.  */

#include "config.h"
#include "system.h"
#include "intl.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "ggc.h"
#include "output.h"
#include "langhooks.h"
#include "opts.h"
#include "options.h"
#include "flags.h"
#include "toplev.h"
#include "params.h"
#include "diagnostic.h"
#include "tm_p.h"               /* For OPTIMIZATION_OPTIONS.  */
#include "insn-attr.h"          /* For INSN_SCHEDULING.  */
#include "target.h"
#include "tree-pass.h"

/* Value of the -G xx switch, and whether it was passed or not.  */
unsigned HOST_WIDE_INT g_switch_value;
bool g_switch_set;

/* True if we should exit after parsing options.  */
bool exit_after_options;

/* Print various extra warnings.  -W/-Wextra.  */
bool extra_warnings;

/* True to warn about any objects definitions whose size is larger
   than N bytes.  Also want about function definitions whose returned
   values are larger than N bytes, where N is `larger_than_size'.  */
bool warn_larger_than;
HOST_WIDE_INT larger_than_size;

/* Nonzero means warn about constructs which might not be
   strict-aliasing safe.  */
int warn_strict_aliasing;

/* Nonzero means warn about optimizations which rely on undefined
   signed overflow.  */
int warn_strict_overflow;

/* Hack for cooperation between set_Wunused and set_Wextra.  */
static bool maybe_warn_unused_parameter;

/* Type(s) of debugging information we are producing (if any).  See
   flags.h for the definitions of the different possible types of
   debugging information.  */
enum debug_info_type write_symbols = NO_DEBUG;

/* Level of debugging information we are producing.  See flags.h for
   the definitions of the different possible levels.  */
enum debug_info_level debug_info_level = DINFO_LEVEL_NONE;

/* Nonzero means use GNU-only extensions in the generated symbolic
   debugging information.  Currently, this only has an effect when
   write_symbols is set to DBX_DEBUG, XCOFF_DEBUG, or DWARF_DEBUG.  */
bool use_gnu_debug_info_extensions;

/* The default visibility for all symbols (unless overridden) */
enum symbol_visibility default_visibility = VISIBILITY_DEFAULT;

/* Disable unit-at-a-time for frontends that might be still broken in this
   respect.  */

bool no_unit_at_a_time_default;

/* Global visibility options.  */
struct visibility_flags visibility_options;

/* What to print when a switch has no documentation.  */
static const char undocumented_msg[] = N_("This switch lacks documentation");

/* Used for bookkeeping on whether user set these flags so
   -fprofile-use/-fprofile-generate does not use them.  */
static bool profile_arc_flag_set, flag_profile_values_set;
static bool flag_unroll_loops_set, flag_tracer_set;
static bool flag_value_profile_transformations_set;
static bool flag_peel_loops_set, flag_branch_probabilities_set;

/* Input file names.  */
const char **in_fnames;
unsigned num_in_fnames;

static int common_handle_option (size_t scode, const char *arg, int value,
                                 unsigned int lang_mask);
static void handle_param (const char *);
static void set_Wextra (int);
static unsigned int handle_option (const char **argv, unsigned int lang_mask);
static char *write_langs (unsigned int lang_mask);
static void complain_wrong_lang (const char *, const struct cl_option *,
                                 unsigned int lang_mask);
static void handle_options (unsigned int, const char **, unsigned int);
static void set_debug_level (enum debug_info_type type, int extended,
                             const char *arg);

/* If ARG is a non-negative integer made up solely of digits, return its
   value, otherwise return -1.  */
static int
integral_argument (const char *arg)
{
  const char *p = arg;

  while (*p && ISDIGIT (*p))
    p++;

  if (*p == '\0')
    return atoi (arg);

  return -1;
}

/* Return a malloced slash-separated list of languages in MASK.  */
static char *
write_langs (unsigned int mask)
{
  unsigned int n = 0, len = 0;
  const char *lang_name;
  char *result;

  for (n = 0; (lang_name = lang_names[n]) != 0; n++)
    if (mask & (1U << n))
      len += strlen (lang_name) + 1;

  result = XNEWVEC (char, len);
  len = 0;
  for (n = 0; (lang_name = lang_names[n]) != 0; n++)
    if (mask & (1U << n))
      {
        if (len)
          result[len++] = '/';
        strcpy (result + len, lang_name);
        len += strlen (lang_name);
      }

  result[len] = 0;

  return result;
}

/* Complain that switch OPT_INDEX does not apply to this front end.  */
static void
complain_wrong_lang (const char *text, const struct cl_option *option,
                     unsigned int lang_mask)
{
  char *ok_langs, *bad_lang;

  ok_langs = write_langs (option->flags);
  bad_lang = write_langs (lang_mask);

  /* Eventually this should become a hard error IMO.  */
  warning (0, "command line option \"%s\" is valid for %s but not for %s",
           text, ok_langs, bad_lang);

  free (ok_langs);
  free (bad_lang);
}

/* Handle the switch beginning at ARGV for the language indicated by
   LANG_MASK.  Returns the number of switches consumed.  */
static unsigned int
handle_option (const char **argv, unsigned int lang_mask)
{
  size_t opt_index;
  const char *opt, *arg = 0;
  char *dup = 0;
  int value = 1;
  unsigned int result = 0;
  const struct cl_option *option;

  opt = argv[0];

  opt_index = find_opt (opt + 1, lang_mask | CL_COMMON | CL_TARGET);
  if (opt_index == cl_options_count
      && (opt[1] == 'W' || opt[1] == 'f' || opt[1] == 'm')
      && opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-')
    {
      /* 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, lang_mask | CL_COMMON | CL_TARGET);
    }

  if (opt_index == cl_options_count)
    goto done;

  option = &cl_options[opt_index];

  /* Reject negative form of switches that don't take negatives as
     unrecognized.  */
  if (!value && (option->flags & CL_REJECT_NEGATIVE))
    goto done;

  /* We've recognized this switch.  */
  result = 1;

  /* Check to see if the option is disabled for this configuration.  */
  if (option->flags & CL_DISABLED)
    {
      error ("command line option %qs"
             " is not supported by this configuration", opt);
      goto done;
    }

  /* Sort out any argument the switch takes.  */
  if (option->flags & CL_JOINED)
    {
      /* 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[0] + cl_options[opt_index].opt_len + 1;
      if (!value)
        arg += strlen ("no-");

      if (*arg == '\0' && !(option->flags & CL_MISSING_OK))
        {
          if (option->flags & CL_SEPARATE)
            {
              arg = argv[1];
              result = 2;
            }
          else
            /* Missing argument.  */
            arg = NULL;
        }
    }
  else if (option->flags & CL_SEPARATE)
    {
      arg = argv[1];
      result = 2;
    }

  /* Now we've swallowed any potential argument, complain if this
     is a switch for a different front end.  */
  if (!(option->flags & (lang_mask | CL_COMMON | CL_TARGET)))
    {
      complain_wrong_lang (argv[0], option, lang_mask);
      goto done;
    }

  if (arg == NULL && (option->flags & (CL_JOINED | CL_SEPARATE)))
    {
      if (!lang_hooks.missing_argument (opt, opt_index))
        error ("missing argument to \"%s\"", opt);
      goto done;
    }

  /* If the switch takes an integer, convert it.  */
  if (arg && (option->flags & CL_UINTEGER))
    {
      value = integral_argument (arg);
      if (value == -1)
        {
          error ("argument to \"%s\" should be a non-negative integer",
                 option->opt_text);
          goto done;
        }
    }

  if (option->flag_var)
    switch (option->var_type)
      {
      case CLVC_BOOLEAN:
        *(int *) option->flag_var = value;
        break;

      case CLVC_EQUAL:
        *(int *) option->flag_var = (value
                                     ? option->var_value
                                     : !option->var_value);
        break;

      case CLVC_BIT_CLEAR:
      case CLVC_BIT_SET:
        if ((value != 0) == (option->var_type == CLVC_BIT_SET))
          *(int *) option->flag_var |= option->var_value;
        else
          *(int *) option->flag_var &= ~option->var_value;
        if (option->flag_var == &target_flags)
          target_flags_explicit |= option->var_value;
        break;

      case CLVC_STRING:
        *(const char **) option->flag_var = arg;
        break;
      }

  if (option->flags & lang_mask)
    if (lang_hooks.handle_option (opt_index, arg, value) == 0)
      result = 0;

  if (result && (option->flags & CL_COMMON))
    if (common_handle_option (opt_index, arg, value, lang_mask) == 0)
      result = 0;

  if (result && (option->flags & CL_TARGET))
    if (!targetm.handle_option (opt_index, arg, value))
      result = 0;

 done:
  if (dup)
    free (dup);
  return result;
}

/* Handle FILENAME from the command line.  */
static void
add_input_filename (const char *filename)
{
  num_in_fnames++;
  in_fnames = xrealloc (in_fnames, num_in_fnames * sizeof (in_fnames[0]));
  in_fnames[num_in_fnames - 1] = filename;
}

/* Decode and handle the vector of command line options.  LANG_MASK
   contains has a single bit set representing the current
   language.  */
static void
handle_options (unsigned int argc, const char **argv, unsigned int lang_mask)
{
  unsigned int n, i;

  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')
        {
          if (main_input_filename == NULL)
            main_input_filename = opt;
          add_input_filename (opt);
          n = 1;
          continue;
        }

      n = handle_option (argv + i, lang_mask);

      if (!n)
        {
          n = 1;
          error ("unrecognized command line option \"%s\"", opt);
        }
    }
}

/* Parse command line options and set default flag values.  Do minimal
   options processing.  */
void
decode_options (unsigned int argc, const char **argv)
{
  unsigned int i, lang_mask;

  /* Perform language-specific options initialization.  */
  lang_mask = lang_hooks.init_options (argc, argv);

  lang_hooks.initialize_diagnostics (global_dc);

  /* Scan to see what optimization level has been specified.  That will
     determine the default value of many flags.  */
  for (i = 1; i < argc; i++)
    {
      if (!strcmp (argv[i], "-O"))
        {
          optimize = 1;
          optimize_size = 0;
        }
      else if (argv[i][0] == '-' && argv[i][1] == 'O')
        {
          /* Handle -Os, -O2, -O3, -O69, ...  */
          const char *p = &argv[i][2];

          if ((p[0] == 's') && (p[1] == 0))
            {
              optimize_size = 1;

              /* Optimizing for size forces optimize to be 2.  */
              optimize = 2;
            }
          else
            {
              const int optimize_val = read_integral_parameter (p, p - 2, -1);
              if (optimize_val != -1)
                {
                  optimize = optimize_val;
                  optimize_size = 0;
                }
            }
        }
    }

  if (!optimize)
    {
      flag_merge_constants = 0;
    }

  if (optimize >= 1)
    {
      flag_defer_pop = 1;
#ifdef DELAY_SLOTS
      flag_delayed_branch = 1;
#endif
#ifdef CAN_DEBUG_WITHOUT_FP
      flag_omit_frame_pointer = 1;
#endif
      flag_guess_branch_prob = 1;
      flag_cprop_registers = 1;
      flag_if_conversion = 1;
      flag_if_conversion2 = 1;
      flag_ipa_pure_const = 1;
      flag_ipa_reference = 1;
      flag_split_wide_types = 1;
      flag_tree_ccp = 1;
      flag_tree_dce = 1;
      flag_tree_dom = 1;
      flag_tree_dse = 1;
      flag_tree_ter = 1;
      flag_tree_sra = 1;
      flag_tree_copyrename = 1;
      flag_tree_fre = 1;
      flag_tree_copy_prop = 1;
      flag_tree_sink = 1;
      flag_tree_salias = 1;
      if (!no_unit_at_a_time_default)
        flag_unit_at_a_time = 1;

      if (!optimize_size)
        {
          /* Loop header copying usually increases size of the code.  This used
             not to be true, since quite often it is possible to verify that
             the condition is satisfied in the first iteration and therefore
             to eliminate it.  Jump threading handles these cases now.  */
          flag_tree_ch = 1;
        }
    }

  if (optimize >= 2)
    {
      flag_thread_jumps = 1;
      flag_crossjumping = 1;
      flag_optimize_sibling_calls = 1;
      flag_forward_propagate = 1;
      flag_cse_follow_jumps = 1;
      flag_gcse = 1;
      flag_expensive_optimizations = 1;
      flag_ipa_type_escape = 1;
      flag_rerun_cse_after_loop = 1;
      flag_caller_saves = 1;
      flag_peephole2 = 1;
#ifdef INSN_SCHEDULING
      flag_schedule_insns = 1;
      flag_schedule_insns_after_reload = 1;
#endif
      flag_regmove = 1;
      flag_strict_aliasing = 1;
      flag_strict_overflow = 1;
      flag_delete_null_pointer_checks = 1;
      flag_reorder_blocks = 1;
      flag_reorder_functions = 1;
      flag_tree_store_ccp = 1;
      flag_tree_store_copy_prop = 1;
      flag_tree_vrp = 1;

      if (!optimize_size)
        {
          /* PRE tends to generate bigger code.  */
          flag_tree_pre = 1;
        }
    }

  if (optimize >= 3)
    {
      flag_inline_functions = 1;
      flag_unswitch_loops = 1;
      flag_gcse_after_reload = 1;
    }

  if (optimize < 2 || optimize_size)
    {
      align_loops = 1;
      align_jumps = 1;
      align_labels = 1;
      align_functions = 1;

      /* Don't reorder blocks when optimizing for size because extra
         jump insns may be created; also barrier may create extra padding.

         More correctly we should have a block reordering mode that tried
         to minimize the combined size of all the jumps.  This would more
         or less automatically remove extra jumps, but would also try to
         use more short jumps instead of long jumps.  */
      flag_reorder_blocks = 0;
      flag_reorder_blocks_and_partition = 0;
    }

  if (optimize_size)
    {
      /* Inlining of very small functions usually reduces total size.  */
      set_param_value ("max-inline-insns-single", 5);
      set_param_value ("max-inline-insns-auto", 5);
      flag_inline_functions = 1;

      /* We want to crossjump as much as possible.  */
      set_param_value ("min-crossjump-insns", 1);
    }

  /* Initialize whether `char' is signed.  */
  flag_signed_char = DEFAULT_SIGNED_CHAR;
  /* Set this to a special "uninitialized" value.  The actual default is set
     after target options have been processed.  */
  flag_short_enums = 2;

  /* Initialize target_flags before OPTIMIZATION_OPTIONS so the latter can
     modify it.  */
  target_flags = targetm.default_target_flags;

  /* Some tagets have ABI-specified unwind tables.  */
  flag_unwind_tables = targetm.unwind_tables_default;

#ifdef OPTIMIZATION_OPTIONS
  /* Allow default optimizations to be specified on a per-machine basis.  */
  OPTIMIZATION_OPTIONS (optimize, optimize_size);
#endif

  handle_options (argc, argv, lang_mask);

  if (flag_pie)
    flag_pic = flag_pie;
  if (flag_pic && !flag_pie)
    flag_shlib = 1;

  if (flag_no_inline == 2)
    flag_no_inline = 0;
  else
    flag_really_no_inline = flag_no_inline;

  /* Set flag_no_inline before the post_options () hook.  The C front
     ends use it to determine tree inlining defaults.  FIXME: such
     code should be lang-independent when all front ends use tree
     inlining, in which case it, and this condition, should be moved
     to the top of process_options() instead.  */
  if (optimize == 0)
    {
      /* Inlining does not work if not optimizing,
         so force it not to be done.  */
      flag_no_inline = 1;
      warn_inline = 0;

      /* The c_decode_option function and decode_option hook set
         this to `2' if -Wall is used, so we can avoid giving out
         lots of errors for people who don't realize what -Wall does.  */
      if (warn_uninitialized == 1)
        warning (OPT_Wuninitialized,
                 "-Wuninitialized is not supported without -O");
    }

  if (flag_really_no_inline == 2)
    flag_really_no_inline = flag_no_inline;

  /* The optimization to partition hot and cold basic blocks into separate
     sections of the .o and executable files does not work (currently)
     with exception handling.  This is because there is no support for
     generating unwind info.  If flag_exceptions is turned on we need to
     turn off the partitioning optimization.  */

  if (flag_exceptions && flag_reorder_blocks_and_partition)
    {
      inform
            ("-freorder-blocks-and-partition does not work with exceptions");
      flag_reorder_blocks_and_partition = 0;
      flag_reorder_blocks = 1;
    }

  /* If user requested unwind info, then turn off the partitioning
     optimization.  */

  if (flag_unwind_tables && ! targetm.unwind_tables_default
      && flag_reorder_blocks_and_partition)
    {
      inform ("-freorder-blocks-and-partition does not support unwind info");
      flag_reorder_blocks_and_partition = 0;
      flag_reorder_blocks = 1;
    }

  /* If the target requested unwind info, then turn off the partitioning
     optimization with a different message.  Likewise, if the target does not
     support named sections.  */

  if (flag_reorder_blocks_and_partition
      && (!targetm.have_named_sections
          || (flag_unwind_tables && targetm.unwind_tables_default)))
    {
      inform
       ("-freorder-blocks-and-partition does not work on this architecture");
      flag_reorder_blocks_and_partition = 0;
      flag_reorder_blocks = 1;
    }
}

#define LEFT_COLUMN     27

/* Output ITEM, of length ITEM_WIDTH, in the left column,
   followed by word-wrapped HELP in a second column.  */
static void
wrap_help (const char *help,
           const char *item,
           unsigned int item_width,
           unsigned int columns)
{
  unsigned int col_width = LEFT_COLUMN;
  unsigned int remaining, room, len;

  remaining = strlen (help);

  do
    {
      room = columns - 3 - MAX (col_width, item_width);
      if (room > columns)
        room = 0;
      len = remaining;

      if (room < len)
        {
          unsigned int i;

          for (i = 0; help[i]; i++)
            {
              if (i >= room && len != remaining)
                break;
              if (help[i] == ' ')
                len = i;
              else if ((help[i] == '-' || help[i] == '/')
                       && help[i + 1] != ' '
                       && i > 0 && ISALPHA (help[i - 1]))
                len = i + 1;
            }
        }

      printf( "  %-*.*s %.*s\n", col_width, item_width, item, len, help);
      item_width = 0;
      while (help[len] == ' ')
        len++;
      help += len;
      remaining -= len;
    }
  while (remaining);
}

/* Print help for a specific front-end, etc.  */
static void
print_filtered_help (unsigned int include_flags,
                     unsigned int exclude_flags,
                     unsigned int any_flags,
                     unsigned int columns)
{
  unsigned int i;
  const char *help;
  static char *printed = NULL;
  bool found = false;
  bool displayed = false;

  if (include_flags == CL_PARAMS)
    {
      for (i = 0; i < LAST_PARAM; i++)
        {
          const char *param = compiler_params[i].option;

          help = compiler_params[i].help;
          if (help == NULL || *help == '\0')
            {
              if (exclude_flags & CL_UNDOCUMENTED)
                continue;
              help = undocumented_msg;
            }

          /* Get the translation.  */
          help = _(help);

          wrap_help (help, param, strlen (param), columns);
        }
      putchar ('\n');
      return;
    }

  if (!printed)
    printed = xcalloc (1, cl_options_count);

  for (i = 0; i < cl_options_count; i++)
    {
      static char new_help[128];
      const struct cl_option *option = cl_options + i;
      unsigned int len;
      const char *opt;
      const char *tab;

      if (include_flags == 0
          || ((option->flags & include_flags) != include_flags))
        {
          if ((option->flags & any_flags) == 0)
            continue;
        }

      /* Skip unwanted switches.  */
      if ((option->flags & exclude_flags) != 0)
        continue;

      found = true;
      /* Skip switches that have already been printed.  */
      if (printed[i])
        continue;

      printed[i] = true;

      help = option->help;
      if (help == NULL)
        {
          if (exclude_flags & CL_UNDOCUMENTED)
            continue;
          help = undocumented_msg;
        }

      /* Get the translation.  */
      help = _(help);

      /* Find the gap between the name of the
         option and its descriptive text.  */
      tab = strchr (help, '\t');
      if (tab)
        {
          len = tab - help;
          opt = help;
          help = tab + 1;
        }
      else
        {
          opt = option->opt_text;
          len = strlen (opt);
        }

      /* With the -Q option enabled we change the descriptive text associated
         with an option to be an indication of its current setting.  */
      if (!quiet_flag)
        {
          if (len < (LEFT_COLUMN + 2))
            strcpy (new_help, "\t\t");
          else
            strcpy (new_help, "\t");

          if (option->flag_var != NULL)
            {
              if (option->flags & CL_JOINED)
                {
                  if (option->var_type == CLVC_STRING)
                    {
                      if (* (const char **) option->flag_var != NULL)
                        snprintf (new_help + strlen (new_help),
                                  sizeof (new_help) - strlen (new_help),
                                  * (const char **) option->flag_var);
                    }
                  else
                    sprintf (new_help + strlen (new_help),
                             "%#x", * (int *) option->flag_var);
                }
              else
                strcat (new_help, option_enabled (i)
                        ? _("[enabled]") : _("[disabled]"));
            }

          help = new_help;
        }

      wrap_help (help, opt, len, columns);
      displayed = true;
    }

  if (! found)
    printf (_(" No options with the desired characteristics were found\n"));
  else if (! displayed)
    printf (_(" All options with the desired characteristics have already been displayed\n"));

  putchar ('\n');
}

/* Display help for a specified type of option.
   The options must have ALL of the INCLUDE_FLAGS set
   ANY of the flags in the ANY_FLAGS set
   and NONE of the EXCLUDE_FLAGS set.  */
static void
print_specific_help (unsigned int include_flags,
                     unsigned int exclude_flags,
                     unsigned int any_flags)
{
  unsigned int all_langs_mask = (1U << cl_lang_count) - 1;
  const char * description = NULL;
  const char * descrip_extra = "";
  size_t i;
  unsigned int flag;
  static unsigned int columns = 0;

  /* Sanity check: Make sure that we do not have more
     languages than we have bits available to enumerate them.  */
  gcc_assert ((1U << cl_lang_count) < CL_MIN_OPTION_CLASS);

  /* If we have not done so already, obtain
     the desired maximum width of the output.  */
  if (columns == 0)
    {
      const char *p;

      GET_ENVIRONMENT (p, "COLUMNS");
      if (p != NULL)
        {
          int value = atoi (p);

          if (value > 0)
            columns = value;
        }

      if (columns == 0)
        /* Use a reasonable default.  */
        columns = 80;
    }

  /* Decide upon the title for the options that we are going to display.  */
  for (i = 0, flag = 1; flag <= CL_MAX_OPTION_CLASS; flag <<= 1, i ++)
    {
      switch (flag & include_flags)
        {
        case 0:
          break;

        case CL_TARGET:
          description = _("The following options are target specific");
          break;
        case CL_WARNING:
          description = _("The following options control compiler warning messages");
          break;
        case CL_OPTIMIZATION:
          description = _("The following options control optimizations");
          break;
        case CL_COMMON:
          description = _("The following options are language-independent");
          break;
        case CL_PARAMS:
          description = _("The --param option recognizes the following as parameters");
          break;
        default:
          if (i >= cl_lang_count)
            break;
          if ((exclude_flags & ((1U << cl_lang_count) - 1)) != 0)
            {
              description = _("The following options are specific to the language ");
              descrip_extra = lang_names [i];
            }
          else
            description = _("The following options are supported by, amoung others, the language ");
          break;
        }
    }

  if (description == NULL)
    {
      if (any_flags == 0)
        {
          if (include_flags == CL_UNDOCUMENTED)
            description = _("The following options are not documented");
          else
            {
              internal_error ("unrecognized include_flags 0x%x passed to print_specific_help",
                              include_flags);
              return;
            }
        }
      else
        {
          if (any_flags & all_langs_mask)
            description = _("The following options are language-related");
          else
            description = _("The following options are language-independent");
        }
    }

  printf ("%s%s:\n", description, descrip_extra);
  print_filtered_help (include_flags, exclude_flags, any_flags, columns);
}

/* Handle target- and language-independent options.  Return zero to
   generate an "unknown option" message.  Only options that need
   extra handling need to be listed here; if you simply want
   VALUE assigned to a variable, it happens automatically.  */

static int
common_handle_option (size_t scode, const char *arg, int value,
                      unsigned int lang_mask)
{
  enum opt_code code = (enum opt_code) scode;

  switch (code)
    {
    case OPT__param:
      handle_param (arg);
      break;

    case OPT_fhelp:
    case OPT__help:
      {
        unsigned int all_langs_mask = (1U << cl_lang_count) - 1;
        unsigned int undoc_mask;
        unsigned int i;

        undoc_mask = extra_warnings ? 0 : CL_UNDOCUMENTED;
        /* First display any single language specific options.  */
        for (i = 0; i < cl_lang_count; i++)
          print_specific_help
            (1U << i, (all_langs_mask & (~ (1U << i))) | undoc_mask, 0);
        /* Next display any multi language specific options.  */
        print_specific_help (0, undoc_mask, all_langs_mask);
        /* Then display any remaining, non-language options.  */
        for (i = CL_MIN_OPTION_CLASS; i <= CL_MAX_OPTION_CLASS; i <<= 1)
          print_specific_help (i, undoc_mask, 0);
        exit_after_options = true;
        break;
      }

    case OPT_ftarget_help:
    case OPT__target_help:
      print_specific_help (CL_TARGET, CL_UNDOCUMENTED, 0);
      exit_after_options = true;
      break;

    case OPT_fhelp_:
    case OPT__help_:
      {
        const char * a = arg;
        unsigned int include_flags = 0;
        /* Note - by default we include undocumented options when listing
           specific classes.  If you only want to see documented options
           then add ",^undocumented" to the --help= option.  e.g.:

           --help=target,^undocumented  */
        unsigned int exclude_flags = 0;

        /* Walk along the argument string, parsing each word in turn.
           The format is:
           arg = [^]{word}[,{arg}]
           word = {optimizers|target|warnings|undocumented|params}  */
        while (* a != 0)
          {
            static struct
            {
              const char * string;
              unsigned int flag;
            }
            specifics[] =
            {
              { "optimizers", CL_OPTIMIZATION },
              { "target", CL_TARGET },
              { "warnings", CL_WARNING },
              { "undocumented", CL_UNDOCUMENTED },
              { "params", CL_PARAMS },
              { "joined", CL_JOINED },
              { "separate", CL_SEPARATE },
              { NULL, 0 }
            };
            unsigned int * pflags;
            char * comma;
            unsigned int len;
            unsigned int i;

            if (* a == '^')
              {
                ++ a;
                pflags = & exclude_flags;
              }
            else
              pflags = & include_flags;

            comma = strchr (a, ',');
            if (comma == NULL)
              len = strlen (a);
            else
              len = comma - a;

            for (i = 0; specifics[i].string != NULL; i++)
              if (strncasecmp (a, specifics[i].string, len) == 0)
                {
                  * pflags |= specifics[i].flag;
                  break;
                }

            if (specifics[i].string == NULL)
              {
                /* Check to see if the string matches a language name.  */
                for (i = 0; i < cl_lang_count; i++)
                  if (strncasecmp (a, lang_names[i], len) == 0)
                    {
                      * pflags |= 1U << i;
                      break;
                    }

                if (i == cl_lang_count)
                  fnotice (stderr,
                           "warning: unrecognized argument to --help= switch: %.*s\n",
                           len, a);
              }

            if (comma == NULL)
              break;
            a = comma + 1;
          }

        if (include_flags)
          print_specific_help (include_flags, exclude_flags, 0);
        exit_after_options = true;
        break;
      }

    case OPT__version:
      print_version (stderr, "");
      exit_after_options = true;
      break;

    case OPT_G:
      g_switch_value = value;
      g_switch_set = true;
      break;

    case OPT_O:
    case OPT_Os:
      /* Currently handled in a prescan.  */
      break;

    case OPT_W:
      /* For backward compatibility, -W is the same as -Wextra.  */
      set_Wextra (value);
      break;

    case OPT_Werror_:
      enable_warning_as_error (arg, value, lang_mask);
      break;

    case OPT_Wextra:
      set_Wextra (value);
      break;

    case OPT_Wlarger_than_:
      larger_than_size = value;
      warn_larger_than = value != -1;
      break;

    case OPT_Wstrict_aliasing:
    case OPT_Wstrict_aliasing_:
      warn_strict_aliasing = value;
      break;

    case OPT_Wstrict_overflow:
    case OPT_Wstrict_overflow_:
      warn_strict_overflow = value;
      break;

    case OPT_Wunused:
      set_Wunused (value);
      break;

    case OPT_aux_info:
    case OPT_aux_info_:
      aux_info_file_name = arg;
      flag_gen_aux_info = 1;
      break;

    case OPT_auxbase:
      aux_base_name = arg;
      break;

    case OPT_auxbase_strip:
      {
        char *tmp = xstrdup (arg);
        strip_off_ending (tmp, strlen (tmp));
        if (tmp[0])
          aux_base_name = tmp;
      }
      break;

    case OPT_d:
      decode_d_option (arg);
      break;

    case OPT_dumpbase:
      dump_base_name = arg;
      break;

    case OPT_falign_functions_:
      align_functions = value;
      break;

    case OPT_falign_jumps_:
      align_jumps = value;
      break;

    case OPT_falign_labels_:
      align_labels = value;
      break;

    case OPT_falign_loops_:
      align_loops = value;
      break;

    case OPT_fbranch_probabilities:
      flag_branch_probabilities_set = true;
      break;

    case OPT_fcall_used_:
      fix_register (arg, 0, 1);
      break;

    case OPT_fcall_saved_:
      fix_register (arg, 0, 0);
      break;

    case OPT_fdiagnostics_show_location_:
      if (!strcmp (arg, "once"))
        diagnostic_prefixing_rule (global_dc) = DIAGNOSTICS_SHOW_PREFIX_ONCE;
      else if (!strcmp (arg, "every-line"))
        diagnostic_prefixing_rule (global_dc)
          = DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE;
      else
        return 0;
      break;

    case OPT_fdiagnostics_show_option:
      global_dc->show_option_requested = true;
      break;

    case OPT_fdump_:
      if (!dump_switch_p (arg))
        return 0;
      break;

    case OPT_ffast_math:
      set_fast_math_flags (value);
      break;

    case OPT_ffixed_:
      fix_register (arg, 1, 1);
      break;

    case OPT_finline_limit_:
    case OPT_finline_limit_eq:
      set_param_value ("max-inline-insns-single", value / 2);
      set_param_value ("max-inline-insns-auto", value / 2);
      break;

    case OPT_fmessage_length_:
      pp_set_line_maximum_length (global_dc->printer, value);
      break;

    case OPT_fpack_struct_:
      if (value <= 0 || (value & (value - 1)) || value > 16)
        error ("structure alignment must be a small power of two, not %d", value);
      else
        {
          initial_max_fld_align = value;
          maximum_field_alignment = value * BITS_PER_UNIT;
        }
      break;

    case OPT_fpeel_loops:
      flag_peel_loops_set = true;
      break;

    case OPT_fprofile_arcs:
      profile_arc_flag_set = true;
      break;

    case OPT_fprofile_use:
      if (!flag_branch_probabilities_set)
        flag_branch_probabilities = value;
      if (!flag_profile_values_set)
        flag_profile_values = value;
      if (!flag_unroll_loops_set)
        flag_unroll_loops = value;
      if (!flag_peel_loops_set)
        flag_peel_loops = value;
      if (!flag_tracer_set)
        flag_tracer = value;
      if (!flag_value_profile_transformations_set)
        flag_value_profile_transformations = value;
      break;

    case OPT_fprofile_generate:
      if (!profile_arc_flag_set)
        profile_arc_flag = value;
      if (!flag_profile_values_set)
        flag_profile_values = value;
      if (!flag_value_profile_transformations_set)
        flag_value_profile_transformations = value;
      break;

    case OPT_fprofile_values:
      flag_profile_values_set = true;
      break;

    case OPT_fvisibility_:
      {
        if (!strcmp(arg, "default"))
          default_visibility = VISIBILITY_DEFAULT;
        else if (!strcmp(arg, "internal"))
          default_visibility = VISIBILITY_INTERNAL;
        else if (!strcmp(arg, "hidden"))
          default_visibility = VISIBILITY_HIDDEN;
        else if (!strcmp(arg, "protected"))
          default_visibility = VISIBILITY_PROTECTED;
        else
          error ("unrecognized visibility value \"%s\"", arg);
      }
      break;

    case OPT_fvpt:
      flag_value_profile_transformations_set = true;
      break;

    case OPT_frandom_seed:
      /* The real switch is -fno-random-seed.  */
      if (value)
        return 0;
      flag_random_seed = NULL;
      break;

    case OPT_frandom_seed_:
      flag_random_seed = arg;
      break;

    case OPT_fsched_verbose_:
#ifdef INSN_SCHEDULING
      fix_sched_param ("verbose", arg);
      break;
#else
      return 0;
#endif

    case OPT_fsched_stalled_insns_:
      flag_sched_stalled_insns = value;
      if (flag_sched_stalled_insns == 0)
        flag_sched_stalled_insns = -1;
      break;

    case OPT_fsched_stalled_insns_dep_:
      flag_sched_stalled_insns_dep = value;
      break;

    case OPT_fstack_limit:
      /* The real switch is -fno-stack-limit.  */
      if (value)
        return 0;
      stack_limit_rtx = NULL_RTX;
      break;

    case OPT_fstack_limit_register_:
      {
        int reg = decode_reg_name (arg);
        if (reg < 0)
          error ("unrecognized register name \"%s\"", arg);
        else
          stack_limit_rtx = gen_rtx_REG (Pmode, reg);
      }
      break;

    case OPT_fstack_limit_symbol_:
      stack_limit_rtx = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (arg));
      break;

    case OPT_ftree_vectorizer_verbose_:
      vect_set_verbosity_level (arg);
      break;

    case OPT_ftls_model_:
      if (!strcmp (arg, "global-dynamic"))
        flag_tls_default = TLS_MODEL_GLOBAL_DYNAMIC;
      else if (!strcmp (arg, "local-dynamic"))
        flag_tls_default = TLS_MODEL_LOCAL_DYNAMIC;
      else if (!strcmp (arg, "initial-exec"))
        flag_tls_default = TLS_MODEL_INITIAL_EXEC;
      else if (!strcmp (arg, "local-exec"))
        flag_tls_default = TLS_MODEL_LOCAL_EXEC;
      else
        warning (0, "unknown tls-model \"%s\"", arg);
      break;

    case OPT_ftracer:
      flag_tracer_set = true;
      break;

    case OPT_funroll_loops:
      flag_unroll_loops_set = true;
      break;

    case OPT_g:
      set_debug_level (NO_DEBUG, DEFAULT_GDB_EXTENSIONS, arg);
      break;

    case OPT_gcoff:
      set_debug_level (SDB_DEBUG, false, arg);
      break;

    case OPT_gdwarf_2:
      set_debug_level (DWARF2_DEBUG, false, arg);
      break;

    case OPT_ggdb:
      set_debug_level (NO_DEBUG, 2, arg);
      break;

    case OPT_gstabs:
    case OPT_gstabs_:
      set_debug_level (DBX_DEBUG, code == OPT_gstabs_, arg);
      break;

    case OPT_gvms:
      set_debug_level (VMS_DEBUG, false, arg);
      break;

    case OPT_gxcoff:
    case OPT_gxcoff_:
      set_debug_level (XCOFF_DEBUG, code == OPT_gxcoff_, arg);
      break;

    case OPT_o:
      asm_file_name = arg;
      break;

    case OPT_pedantic_errors:
      flag_pedantic_errors = pedantic = 1;
      break;

    case OPT_floop_optimize:
    case OPT_frerun_loop_opt:
    case OPT_fstrength_reduce:
      /* These are no-ops, preserved for backward compatibility.  */
      break;

    default:
      /* If the flag was handled in a standard way, assume the lack of
         processing here is intentional.  */
      gcc_assert (cl_options[scode].flag_var);
      break;
    }

  return 1;
}

/* Handle --param NAME=VALUE.  */
static void
handle_param (const char *carg)
{
  char *equal, *arg;
  int value;

  arg = xstrdup (carg);
  equal = strchr (arg, '=');
  if (!equal)
    error ("%s: --param arguments should be of the form NAME=VALUE", arg);
  else
    {
      value = integral_argument (equal + 1);
      if (value == -1)
        error ("invalid --param value %qs", equal + 1);
      else
        {
          *equal = '\0';
          set_param_value (arg, value);
        }
    }

  free (arg);
}

/* Handle -W and -Wextra.  */
static void
set_Wextra (int setting)
{
  extra_warnings = setting;
  warn_unused_parameter = (setting && maybe_warn_unused_parameter);

  /* We save the value of warn_uninitialized, since if they put
     -Wuninitialized on the command line, we need to generate a
     warning about not using it without also specifying -O.  */
  if (setting == 0)
    warn_uninitialized = 0;
  else if (warn_uninitialized != 1)
    warn_uninitialized = 2;
}

/* Initialize unused warning flags.  */
void
set_Wunused (int setting)
{
  warn_unused_function = setting;
  warn_unused_label = setting;
  /* Unused function parameter warnings are reported when either
     ``-Wextra -Wunused'' or ``-Wunused-parameter'' is specified.
     Thus, if -Wextra has already been seen, set warn_unused_parameter;
     otherwise set maybe_warn_extra_parameter, which will be picked up
     by set_Wextra.  */
  maybe_warn_unused_parameter = setting;
  warn_unused_parameter = (setting && extra_warnings);
  warn_unused_variable = setting;
  warn_unused_value = setting;
}

/* The following routines are useful in setting all the flags that
   -ffast-math and -fno-fast-math imply.  */
void
set_fast_math_flags (int set)
{
  flag_trapping_math = !set;
  flag_unsafe_math_optimizations = set;
  flag_finite_math_only = set;
  flag_signed_zeros = !set;
  flag_errno_math = !set;
  if (set)
    {
      flag_signaling_nans = 0;
      flag_rounding_math = 0;
      flag_cx_limited_range = 1;
    }
}

/* Return true iff flags are set as if -ffast-math.  */
bool
fast_math_flags_set_p (void)
{
  return (!flag_trapping_math
          && flag_unsafe_math_optimizations
          && flag_finite_math_only
          && !flag_signed_zeros
          && !flag_errno_math);
}

/* Handle a debug output -g switch.  EXTENDED is true or false to support
   extended output (2 is special and means "-ggdb" was given).  */
static void
set_debug_level (enum debug_info_type type, int extended, const char *arg)
{
  static bool type_explicit;

  use_gnu_debug_info_extensions = extended;

  if (type == NO_DEBUG)
    {
      if (write_symbols == NO_DEBUG)
        {
          write_symbols = PREFERRED_DEBUGGING_TYPE;

          if (extended == 2)
            {
#ifdef DWARF2_DEBUGGING_INFO
              write_symbols = DWARF2_DEBUG;
#elif defined DBX_DEBUGGING_INFO
              write_symbols = DBX_DEBUG;
#endif
            }

          if (write_symbols == NO_DEBUG)
            warning (0, "target system does not support debug output");
        }
    }
  else
    {
      /* Does it conflict with an already selected type?  */
      if (type_explicit && write_symbols != NO_DEBUG && type != write_symbols)
        error ("debug format \"%s\" conflicts with prior selection",
               debug_type_names[type]);
      write_symbols = type;
      type_explicit = true;
    }

  /* A debug flag without a level defaults to level 2.  */
  if (*arg == '\0')
    {
      if (!debug_info_level)
        debug_info_level = 2;
    }
  else
    {
      debug_info_level = integral_argument (arg);
      if (debug_info_level == (unsigned int) -1)
        error ("unrecognised debug output level \"%s\"", arg);
      else if (debug_info_level > 3)
        error ("debug output level %s is too high", arg);
    }
}

/* Return 1 if OPTION is enabled, 0 if it is disabled, or -1 if it isn't
   a simple on-off switch.  */

int
option_enabled (int opt_idx)
{
  const struct cl_option *option = &(cl_options[opt_idx]);

  if (option->flag_var)
    switch (option->var_type)
      {
      case CLVC_BOOLEAN:
        return *(int *) option->flag_var != 0;

      case CLVC_EQUAL:
        return *(int *) option->flag_var == option->var_value;

      case CLVC_BIT_CLEAR:
        return (*(int *) option->flag_var & option->var_value) == 0;

      case CLVC_BIT_SET:
        return (*(int *) option->flag_var & option->var_value) != 0;

      case CLVC_STRING:
        break;
      }
  return -1;
}

/* Fill STATE with the current state of option OPTION.  Return true if
   there is some state to store.  */

bool
get_option_state (int option, struct cl_option_state *state)
{
  if (cl_options[option].flag_var == 0)
    return false;

  switch (cl_options[option].var_type)
    {
    case CLVC_BOOLEAN:
    case CLVC_EQUAL:
      state->data = cl_options[option].flag_var;
      state->size = sizeof (int);
      break;

    case CLVC_BIT_CLEAR:
    case CLVC_BIT_SET:
      state->ch = option_enabled (option);
      state->data = &state->ch;
      state->size = 1;
      break;

    case CLVC_STRING:
      state->data = *(const char **) cl_options[option].flag_var;
      if (state->data == 0)
        state->data = "";
      state->size = strlen (state->data) + 1;
      break;
    }
  return true;
}

/* Enable a warning option as an error.  This is used by -Werror= and
   also by legacy Werror-implicit-function-declaration.  */

void
enable_warning_as_error (const char *arg, int value, unsigned int lang_mask)
{
  char *new_option;
  int option_index;

  new_option = XNEWVEC (char, strlen (arg) + 2);
  new_option[0] = 'W';
  strcpy (new_option + 1, arg);
  option_index = find_opt (new_option, lang_mask);
  if (option_index == N_OPTS)
    {
      error ("-Werror=%s: No option -%s", arg, new_option);
    }
  else
    {
      int kind = value ? DK_ERROR : DK_WARNING;
      diagnostic_classify_diagnostic (global_dc, option_index, kind);
      
      /* -Werror=foo implies -Wfoo.  */
      if (cl_options[option_index].var_type == CLVC_BOOLEAN
          && cl_options[option_index].flag_var
          && kind == DK_ERROR)
        *(int *) cl_options[option_index].flag_var = 1;
    }
  free (new_option);
}