gcc/opts.c

   1 /* Command line option handling.
   2    Copyright (C) 2002, 2003 Free Software Foundation, Inc.
   3    Contributed by Neil Booth.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "intl.h"
  25 #include "coretypes.h"
  26 #include "tm.h"
  27 #include "tree.h"
  28 #include "rtl.h"
  29 #include "ggc.h"
  30 #include "output.h"
  31 #include "langhooks.h"
  32 #include "opts.h"
  33 #include "options.h"
  34 #include "flags.h"
  35 #include "toplev.h"
  36 #include "params.h"
  37 #include "diagnostic.h"
  38 #include "tm_p.h"               /* For OPTIMIZATION_OPTIONS.  */
  39 #include "insn-attr.h"          /* For INSN_SCHEDULING.  */
  40
  41 /* Value of the -G xx switch, and whether it was passed or not.  */
  42 unsigned HOST_WIDE_INT g_switch_value;
  43 bool g_switch_set;
  44
  45 /* True if we should exit after parsing options.  */
  46 bool exit_after_options;
  47
  48 /* If -version.  */
  49 bool version_flag;
  50
  51 /* Print various extra warnings.  -W/-Wextra.  */
  52 bool extra_warnings;
  53
  54 /* Don't print warning messages.  -w.  */
  55 bool inhibit_warnings;
  56
  57 /* Treat warnings as errors.  -Werror.  */
  58 bool warnings_are_errors;
  59
  60 /* Warn if a function returns an aggregate, since there are often
  61    incompatible calling conventions for doing this.  */
  62 bool warn_aggregate_return;
  63
  64 /* Nonzero means warn about pointer casts that increase the required
  65    alignment of the target type (and might therefore lead to a crash
  66    due to a misaligned access).  */
  67 bool warn_cast_align;
  68
  69 /* Nonzero means warn about uses of __attribute__((deprecated))
  70    declarations.  */
  71 bool warn_deprecated_decl = true;
  72
  73 /* Warn when an optimization pass is disabled.  */
  74 bool warn_disabled_optimization;
  75
  76 /* Nonzero means warn if inline function is too large.  */
  77 bool warn_inline;
  78
  79 /* True to warn about any objects definitions whose size is larger
  80    than N bytes.  Also want about function definitions whose returned
  81    values are larger than N bytes, where N is `larger_than_size'.  */
  82 bool warn_larger_than;
  83 HOST_WIDE_INT larger_than_size;
  84
  85 /* Warn about functions which might be candidates for attribute noreturn.  */
  86 bool warn_missing_noreturn;
  87
  88 /* True to warn about code which is never reached.  */
  89 bool warn_notreached;
  90
  91 /* Warn if packed attribute on struct is unnecessary and inefficient.  */
  92 bool warn_packed;
  93
  94 /* Warn when gcc pads a structure to an alignment boundary.  */
  95 bool warn_padded;
  96
  97 /* True means warn about all declarations which shadow others.  */
  98 bool warn_shadow;
  99
 100 /* Nonzero means warn about constructs which might not be
 101    strict-aliasing safe.  */
 102 bool warn_strict_aliasing;
 103
 104 /* True to warn if a switch on an enum, that does not have a default
 105    case, fails to have a case for every enum value.  */
 106 bool warn_switch;
 107
 108 /* Warn if a switch does not have a default case.  */
 109 bool warn_switch_default;
 110
 111 /* Warn if a switch on an enum fails to have a case for every enum
 112    value (regardless of the presence or otherwise of a default case).  */
 113 bool warn_switch_enum;
 114
 115 /* Don't suppress warnings from system headers.  -Wsystem-headers.  */
 116 bool warn_system_headers;
 117
 118 /* True to warn about variables used before they are initialized.  */
 119 int warn_uninitialized;
 120
 121 /* True to warn about unused variables, functions et.al.  */
 122 bool warn_unused_function;
 123 bool warn_unused_label;
 124 bool warn_unused_parameter;
 125 bool warn_unused_variable;
 126 bool warn_unused_value;
 127
 128 /* Hack for cooperation between set_Wunused and set_Wextra.  */
 129 static bool maybe_warn_unused_parameter;
 130
 131 /* Type(s) of debugging information we are producing (if any).  See
 132    flags.h for the definitions of the different possible types of
 133    debugging information.  */
 134 enum debug_info_type write_symbols = NO_DEBUG;
 135
 136 /* Level of debugging information we are producing.  See flags.h for
 137    the definitions of the different possible levels.  */
 138 enum debug_info_level debug_info_level = DINFO_LEVEL_NONE;
 139
 140 /* Nonzero means use GNU-only extensions in the generated symbolic
 141    debugging information.  Currently, this only has an effect when
 142    write_symbols is set to DBX_DEBUG, XCOFF_DEBUG, or DWARF_DEBUG.  */
 143 bool use_gnu_debug_info_extensions;
 144
 145 /* Columns of --help display.  */
 146 static unsigned int columns = 80;
 147
 148 /* What to print when a switch has no documentation.  */
 149 static const char undocumented_msg[] = N_("This switch lacks documentation");
 150
 151 /* Input file names.  */
 152 const char **in_fnames;
 153 unsigned num_in_fnames;
 154
 155 static size_t find_opt (const char *, int);
 156 static int common_handle_option (size_t scode, const char *arg, int value);
 157 static void handle_param (const char *);
 158 static void set_Wextra (int);
 159 static unsigned int handle_option (const char **argv, unsigned int lang_mask);
 160 static char *write_langs (unsigned int lang_mask);
 161 static void complain_wrong_lang (const char *, const struct cl_option *,
 162                                  unsigned int lang_mask);
 163 static void handle_options (unsigned int, const char **, unsigned int);
 164 static void wrap_help (const char *help, const char *item, unsigned int);
 165 static void print_help (void);
 166 static void print_param_help (void);
 167 static void print_filtered_help (unsigned int flag);
 168 static unsigned int print_switch (const char *text, unsigned int indent);
 169 static void set_debug_level (enum debug_info_type type, int extended,
 170                              const char *arg);
 171
 172 /* Perform a binary search to find which option the command-line INPUT
 173    matches.  Returns its index in the option array, and N_OPTS
 174    (cl_options_count) on failure.
 175
 176    This routine is quite subtle.  A normal binary search is not good
 177    enough because some options can be suffixed with an argument, and
 178    multiple sub-matches can occur, e.g. input of "-pedantic" matching
 179    the initial substring of "-pedantic-errors".
 180
 181    A more complicated example is -gstabs.  It should match "-g" with
 182    an argument of "stabs".  Suppose, however, that the number and list
 183    of switches are such that the binary search tests "-gen-decls"
 184    before having tested "-g".  This doesn't match, and as "-gen-decls"
 185    is less than "-gstabs", it will become the lower bound of the
 186    binary search range, and "-g" will never be seen.  To resolve this
 187    issue, opts.sh makes "-gen-decls" point, via the back_chain member,
 188    to "-g" so that failed searches that end between "-gen-decls" and
 189    the lexicographically subsequent switch know to go back and see if
 190    "-g" causes a match (which it does in this example).
 191
 192    This search is done in such a way that the longest match for the
 193    front end in question wins.  If there is no match for the current
 194    front end, the longest match for a different front end is returned
 195    (or N_OPTS if none) and the caller emits an error message.  */
 196 static size_t
 197 find_opt (const char *input, int lang_mask)
 198 {
 199   size_t mn, mx, md, opt_len;
 200   size_t match_wrong_lang;
 201   int comp;
 202
 203   mn = 0;
 204   mx = cl_options_count;
 205
 206   /* Find mn such this lexicographical inequality holds:
 207      cl_options[mn] <= input < cl_options[mn + 1].  */
 208   while (mx - mn > 1)
 209     {
 210       md = (mn + mx) / 2;
 211       opt_len = cl_options[md].opt_len;
 212       comp = strncmp (input, cl_options[md].opt_text + 1, opt_len);
 213
 214       if (comp < 0)
 215         mx = md;
 216       else
 217         mn = md;
 218     }
 219
 220   /* This is the switch that is the best match but for a different
 221      front end, or cl_options_count if there is no match at all.  */
 222   match_wrong_lang = cl_options_count;
 223
 224   /* Backtrace the chain of possible matches, returning the longest
 225      one, if any, that fits best.  With current GCC switches, this
 226      loop executes at most twice.  */
 227   do
 228     {
 229       const struct cl_option *opt = &cl_options[mn];
 230
 231       /* Is this switch a prefix of the input?  */
 232       if (!strncmp (input, opt->opt_text + 1, opt->opt_len))
 233         {
 234           /* If language is OK, and the match is exact or the switch
 235              takes a joined argument, return it.  */
 236           if ((opt->flags & lang_mask)
 237               && (input[opt->opt_len] == '\0' || (opt->flags & CL_JOINED)))
 238             return mn;
 239
 240           /* If we haven't remembered a prior match, remember this
 241              one.  Any prior match is necessarily better.  */
 242           if (match_wrong_lang == cl_options_count)
 243             match_wrong_lang = mn;
 244         }
 245
 246       /* Try the next possibility.  This is cl_options_count if there
 247          are no more.  */
 248       mn = opt->back_chain;
 249     }
 250   while (mn != cl_options_count);
 251
 252   /* Return the best wrong match, or cl_options_count if none.  */
 253   return match_wrong_lang;
 254 }
 255
 256 /* If ARG is a non-negative integer made up solely of digits, return its
 257    value, otherwise return -1.  */
 258 static int
 259 integral_argument (const char *arg)
 260 {
 261   const char *p = arg;
 262
 263   while (*p && ISDIGIT (*p))
 264     p++;
 265
 266   if (*p == '\0')
 267     return atoi (arg);
 268
 269   return -1;
 270 }
 271
 272 /* Return a malloced slash-separated list of languages in MASK.  */
 273 static char *
 274 write_langs (unsigned int mask)
 275 {
 276   unsigned int n = 0, len = 0;
 277   const char *lang_name;
 278   char *result;
 279
 280   for (n = 0; (lang_name = lang_names[n]) != 0; n++)
 281     if (mask & (1U << n))
 282       len += strlen (lang_name) + 1;
 283
 284   result = xmalloc (len);
 285   len = 0;
 286   for (n = 0; (lang_name = lang_names[n]) != 0; n++)
 287     if (mask & (1U << n))
 288       {
 289         if (len)
 290           result[len++] = '/';
 291         strcpy (result + len, lang_name);
 292         len += strlen (lang_name);
 293       }
 294
 295   result[len] = 0;
 296
 297   return result;
 298 }
 299
 300 /* Complain that switch OPT_INDEX does not apply to this front end.  */
 301 static void
 302 complain_wrong_lang (const char *text, const struct cl_option *option,
 303                      unsigned int lang_mask)
 304 {
 305   char *ok_langs, *bad_lang;
 306
 307   ok_langs = write_langs (option->flags);
 308   bad_lang = write_langs (lang_mask);
 309
 310   /* Eventually this should become a hard error IMO.  */
 311   warning ("command line option \"%s\" is valid for %s but not for %s",
 312            text, ok_langs, bad_lang);
 313
 314   free (ok_langs);
 315   free (bad_lang);
 316 }
 317
 318 /* Handle the switch beginning at ARGV for the language indicated by
 319    LANG_MASK.  Returns the number of switches consumed.  */
 320 static unsigned int
 321 handle_option (const char **argv, unsigned int lang_mask)
 322 {
 323   size_t opt_index;
 324   const char *opt, *arg = 0;
 325   char *dup = 0;
 326   int value = 1;
 327   unsigned int result = 0;
 328   const struct cl_option *option;
 329
 330   opt = argv[0];
 331
 332   /* Drop the "no-" from negative switches.  */
 333   if ((opt[1] == 'W' || opt[1] == 'f')
 334       && opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-')
 335     {
 336       size_t len = strlen (opt) - 3;
 337
 338       dup = xmalloc (len + 1);
 339       dup[0] = '-';
 340       dup[1] = opt[1];
 341       memcpy (dup + 2, opt + 5, len - 2 + 1);
 342       opt = dup;
 343       value = 0;
 344     }
 345
 346   opt_index = find_opt (opt + 1, lang_mask | CL_COMMON);
 347   if (opt_index == cl_options_count)
 348     goto done;
 349
 350   option = &cl_options[opt_index];
 351
 352   /* Reject negative form of switches that don't take negatives as
 353      unrecognized.  */
 354   if (!value && (option->flags & CL_REJECT_NEGATIVE))
 355     goto done;
 356
 357   /* We've recognized this switch.  */
 358   result = 1;
 359
 360   /* Sort out any argument the switch takes.  */
 361   if (option->flags & CL_JOINED)
 362     {
 363       /* Have arg point to the original switch.  This is because
 364          some code, such as disable_builtin_function, expects its
 365          argument to be persistent until the program exits.  */
 366       arg = argv[0] + cl_options[opt_index].opt_len + 1;
 367       if (!value)
 368         arg += strlen ("no-");
 369
 370       if (*arg == '\0' && !(option->flags & CL_MISSING_OK))
 371         {
 372           if (option->flags & CL_SEPARATE)
 373             {
 374               arg = argv[1];
 375               result = 2;
 376             }
 377           else
 378             /* Missing argument.  */
 379             arg = NULL;
 380         }
 381     }
 382   else if (option->flags & CL_SEPARATE)
 383     {
 384       arg = argv[1];
 385       result = 2;
 386     }
 387
 388   /* Now we've swallowed any potential argument, complain if this
 389      is a switch for a different front end.  */
 390   if (!(option->flags & (lang_mask | CL_COMMON)))
 391     {
 392       complain_wrong_lang (argv[0], option, lang_mask);
 393       goto done;
 394     }
 395
 396   if (arg == NULL && (option->flags & (CL_JOINED | CL_SEPARATE)))
 397     {
 398       if (!(*lang_hooks.missing_argument) (opt, opt_index))
 399         error ("missing argument to \"%s\"", opt);
 400       goto done;
 401     }
 402
 403   /* If the switch takes an integer, convert it.  */
 404   if (arg && (option->flags & CL_UINTEGER))
 405     {
 406       value = integral_argument (arg);
 407       if (value == -1)
 408         {
 409           error ("argument to \"%s\" should be a non-negative integer",
 410                  option->opt_text);
 411           goto done;
 412         }
 413     }
 414
 415   if (option->flags & lang_mask)
 416     if ((*lang_hooks.handle_option) (opt_index, arg, value) == 0)
 417       result = 0;
 418
 419   if (result && (option->flags & CL_COMMON))
 420     if (common_handle_option (opt_index, arg, value) == 0)
 421       result = 0;
 422
 423  done:
 424   if (dup)
 425     free (dup);
 426   return result;
 427 }
 428
 429 /* Decode and handle the vector of command line options.  LANG_MASK
 430    contains has a single bit set representing the current
 431    language.  */
 432 static void
 433 handle_options (unsigned int argc, const char **argv, unsigned int lang_mask)
 434 {
 435   unsigned int n, i;
 436
 437   for (i = 1; i < argc; i += n)
 438     {
 439       const char *opt = argv[i];
 440
 441       /* Interpret "-" or a non-switch as a file name.  */
 442       if (opt[0] != '-' || opt[1] == '\0')
 443         {
 444           main_input_filename = opt;
 445           add_input_filename (opt);
 446           n = 1;
 447           continue;
 448         }
 449
 450       n = handle_option (argv + i, lang_mask);
 451
 452       if (!n)
 453         {
 454           n = 1;
 455           error ("unrecognized command line option \"%s\"", opt);
 456         }
 457     }
 458 }
 459
 460 /* Handle FILENAME from the command line.  */
 461 void
 462 add_input_filename (const char *filename)
 463 {
 464   num_in_fnames++;
 465   in_fnames = xrealloc (in_fnames, num_in_fnames * sizeof (in_fnames[0]));
 466   in_fnames[num_in_fnames - 1] = filename;
 467 }
 468
 469 /* Parse command line options and set default flag values.  Do minimal
 470    options processing.  */
 471 void
 472 decode_options (unsigned int argc, const char **argv)
 473 {
 474   unsigned int i, lang_mask;
 475
 476   /* Perform language-specific options initialization.  */
 477   lang_mask = (*lang_hooks.init_options) (argc, argv);
 478
 479   lang_hooks.initialize_diagnostics (global_dc);
 480
 481   /* Scan to see what optimization level has been specified.  That will
 482      determine the default value of many flags.  */
 483   for (i = 1; i < argc; i++)
 484     {
 485       if (!strcmp (argv[i], "-O"))
 486         {
 487           optimize = 1;
 488           optimize_size = 0;
 489         }
 490       else if (argv[i][0] == '-' && argv[i][1] == 'O')
 491         {
 492           /* Handle -Os, -O2, -O3, -O69, ...  */
 493           const char *p = &argv[i][2];
 494
 495           if ((p[0] == 's') && (p[1] == 0))
 496             {
 497               optimize_size = 1;
 498
 499               /* Optimizing for size forces optimize to be 2.  */
 500               optimize = 2;
 501             }
 502           else
 503             {
 504               const int optimize_val = read_integral_parameter (p, p - 2, -1);
 505               if (optimize_val != -1)
 506                 {
 507                   optimize = optimize_val;
 508                   optimize_size = 0;
 509                 }
 510             }
 511         }
 512     }
 513
 514   if (!optimize)
 515     {
 516       flag_merge_constants = 0;
 517     }
 518
 519   if (optimize >= 1)
 520     {
 521       flag_defer_pop = 1;
 522       flag_thread_jumps = 1;
 523 #ifdef DELAY_SLOTS
 524       flag_delayed_branch = 1;
 525 #endif
 526 #ifdef CAN_DEBUG_WITHOUT_FP
 527       flag_omit_frame_pointer = 1;
 528 #endif
 529       flag_guess_branch_prob = 1;
 530       flag_cprop_registers = 1;
 531       flag_loop_optimize = 1;
 532       flag_crossjumping = 1;
 533       flag_if_conversion = 1;
 534       flag_if_conversion2 = 1;
 535     }
 536
 537   if (optimize >= 2)
 538     {
 539       flag_optimize_sibling_calls = 1;
 540       flag_cse_follow_jumps = 1;
 541       flag_cse_skip_blocks = 1;
 542       flag_gcse = 1;
 543       flag_expensive_optimizations = 1;
 544       flag_strength_reduce = 1;
 545       flag_rerun_cse_after_loop = 1;
 546       flag_rerun_loop_opt = 1;
 547       flag_caller_saves = 1;
 548       flag_force_mem = 1;
 549       flag_peephole2 = 1;
 550 #ifdef INSN_SCHEDULING
 551       flag_schedule_insns = 1;
 552       flag_schedule_insns_after_reload = 1;
 553 #endif
 554       flag_regmove = 1;
 555       flag_strict_aliasing = 1;
 556       flag_delete_null_pointer_checks = 1;
 557       flag_reorder_blocks = 1;
 558       flag_reorder_functions = 1;
 559       flag_unit_at_a_time = 1;
 560     }
 561
 562   if (optimize >= 3)
 563     {
 564       flag_inline_functions = 1;
 565       flag_rename_registers = 1;
 566       flag_unswitch_loops = 1;
 567       flag_web = 1;
 568     }
 569
 570   if (optimize < 2 || optimize_size)
 571     {
 572       align_loops = 1;
 573       align_jumps = 1;
 574       align_labels = 1;
 575       align_functions = 1;
 576
 577       /* Don't reorder blocks when optimizing for size because extra
 578          jump insns may be created; also barrier may create extra padding.
 579
 580          More correctly we should have a block reordering mode that tried
 581          to minimize the combined size of all the jumps.  This would more
 582          or less automatically remove extra jumps, but would also try to
 583          use more short jumps instead of long jumps.  */
 584       flag_reorder_blocks = 0;
 585     }
 586
 587   /* Initialize whether `char' is signed.  */
 588   flag_signed_char = DEFAULT_SIGNED_CHAR;
 589 #ifdef DEFAULT_SHORT_ENUMS
 590   /* Initialize how much space enums occupy, by default.  */
 591   flag_short_enums = DEFAULT_SHORT_ENUMS;
 592 #endif
 593
 594   /* Initialize target_flags before OPTIMIZATION_OPTIONS so the latter can
 595      modify it.  */
 596   target_flags = 0;
 597   set_target_switch ("");
 598
 599   /* Unwind tables are always present in an ABI-conformant IA-64
 600      object file, so the default should be ON.  */
 601 #ifdef IA64_UNWIND_INFO
 602   flag_unwind_tables = IA64_UNWIND_INFO;
 603 #endif
 604
 605 #ifdef OPTIMIZATION_OPTIONS
 606   /* Allow default optimizations to be specified on a per-machine basis.  */
 607   OPTIMIZATION_OPTIONS (optimize, optimize_size);
 608 #endif
 609
 610   handle_options (argc, argv, lang_mask);
 611
 612   if (flag_pie)
 613     flag_pic = flag_pie;
 614   if (flag_pic && !flag_pie)
 615     flag_shlib = 1;
 616
 617   if (flag_no_inline == 2)
 618     flag_no_inline = 0;
 619   else
 620     flag_really_no_inline = flag_no_inline;
 621
 622   /* Set flag_no_inline before the post_options () hook.  The C front
 623      ends use it to determine tree inlining defaults.  FIXME: such
 624      code should be lang-independent when all front ends use tree
 625      inlining, in which case it, and this condition, should be moved
 626      to the top of process_options() instead.  */
 627   if (optimize == 0)
 628     {
 629       /* Inlining does not work if not optimizing,
 630          so force it not to be done.  */
 631       flag_no_inline = 1;
 632       warn_inline = 0;
 633
 634       /* The c_decode_option function and decode_option hook set
 635          this to `2' if -Wall is used, so we can avoid giving out
 636          lots of errors for people who don't realize what -Wall does.  */
 637       if (warn_uninitialized == 1)
 638         warning ("-Wuninitialized is not supported without -O");
 639     }
 640
 641   if (flag_really_no_inline == 2)
 642     flag_really_no_inline = flag_no_inline;
 643 }
 644
 645 /* Handle target- and language-independent options.  Return zero to
 646    generate an "unknown option" message.  */
 647 static int
 648 common_handle_option (size_t scode, const char *arg,
 649                       int value ATTRIBUTE_UNUSED)
 650 {
 651   enum opt_code code = (enum opt_code) scode;
 652
 653   switch (code)
 654     {
 655     default:
 656       abort ();
 657
 658     case OPT__help:
 659       print_help ();
 660       exit_after_options = true;
 661       break;
 662
 663     case OPT__param:
 664       handle_param (arg);
 665       break;
 666
 667     case OPT__target_help:
 668       display_target_options ();
 669       exit_after_options = true;
 670       break;
 671
 672     case OPT__version:
 673       print_version (stderr, "");
 674       exit_after_options = true;
 675       break;
 676
 677     case OPT_G:
 678       g_switch_value = value;
 679       g_switch_set = true;
 680       break;
 681
 682     case OPT_O:
 683     case OPT_Os:
 684       /* Currently handled in a prescan.  */
 685       break;
 686
 687     case OPT_W:
 688       /* For backward compatibility, -W is the same as -Wextra.  */
 689       set_Wextra (value);
 690       break;
 691
 692     case OPT_Waggregate_return:
 693       warn_aggregate_return = value;
 694       break;
 695
 696     case OPT_Wcast_align:
 697       warn_cast_align = value;
 698       break;
 699
 700     case OPT_Wdeprecated_declarations:
 701       warn_deprecated_decl = value;
 702       break;
 703
 704     case OPT_Wdisabled_optimization:
 705       warn_disabled_optimization = value;
 706       break;
 707
 708     case OPT_Werror:
 709       warnings_are_errors = value;
 710       break;
 711
 712     case OPT_Wextra:
 713       set_Wextra (value);
 714       break;
 715
 716     case OPT_Winline:
 717       warn_inline = value;
 718       break;
 719
 720     case OPT_Wlarger_than_:
 721       larger_than_size = value;
 722       warn_larger_than = value != -1;
 723       break;
 724
 725     case OPT_Wmissing_noreturn:
 726       warn_missing_noreturn = value;
 727       break;
 728
 729     case OPT_Wpacked:
 730       warn_packed = value;
 731       break;
 732
 733     case OPT_Wpadded:
 734       warn_padded = value;
 735       break;
 736
 737     case OPT_Wshadow:
 738       warn_shadow = value;
 739       break;
 740
 741     case OPT_Wstrict_aliasing:
 742       warn_strict_aliasing = value;
 743       break;
 744
 745     case OPT_Wswitch:
 746       warn_switch = value;
 747       break;
 748
 749     case OPT_Wswitch_default:
 750       warn_switch_default = value;
 751       break;
 752
 753     case OPT_Wswitch_enum:
 754       warn_switch_enum = value;
 755       break;
 756
 757     case OPT_Wsystem_headers:
 758       warn_system_headers = value;
 759       break;
 760
 761     case OPT_Wuninitialized:
 762       warn_uninitialized = value;
 763       break;
 764
 765     case OPT_Wunreachable_code:
 766       warn_notreached = value;
 767       break;
 768
 769     case OPT_Wunused:
 770       set_Wunused (value);
 771       break;
 772
 773     case OPT_Wunused_function:
 774       warn_unused_function = value;
 775       break;
 776
 777     case OPT_Wunused_label:
 778       warn_unused_label = value;
 779       break;
 780
 781     case OPT_Wunused_parameter:
 782       warn_unused_parameter = value;
 783       break;
 784
 785     case OPT_Wunused_value:
 786       warn_unused_value = value;
 787       break;
 788
 789     case OPT_Wunused_variable:
 790       warn_unused_variable = value;
 791       break;
 792
 793     case OPT_aux_info:
 794     case OPT_aux_info_:
 795       aux_info_file_name = arg;
 796       flag_gen_aux_info = 1;
 797       break;
 798
 799     case OPT_auxbase:
 800       aux_base_name = arg;
 801       break;
 802
 803     case OPT_auxbase_strip:
 804       {
 805         char *tmp = xstrdup (arg);
 806         strip_off_ending (tmp, strlen (tmp));
 807         if (tmp[0])
 808           aux_base_name = tmp;
 809       }
 810       break;
 811
 812     case OPT_d:
 813       decode_d_option (arg);
 814       break;
 815
 816     case OPT_dumpbase:
 817       dump_base_name = arg;
 818       break;
 819
 820     case OPT_fPIC:
 821       flag_pic = value + value;
 822       break;
 823
 824     case OPT_fPIE:
 825       flag_pie = value + value;
 826       break;
 827
 828     case OPT_falign_functions:
 829       align_functions = !value;
 830       break;
 831
 832     case OPT_falign_functions_:
 833       align_functions = value;
 834       break;
 835
 836     case OPT_falign_jumps:
 837       align_jumps = !value;
 838       break;
 839
 840     case OPT_falign_jumps_:
 841       align_jumps = value;
 842       break;
 843
 844     case OPT_falign_labels:
 845       align_labels = !value;
 846       break;
 847
 848     case OPT_falign_labels_:
 849       align_labels = value;
 850       break;
 851
 852     case OPT_falign_loops:
 853       align_loops = !value;
 854       break;
 855
 856     case OPT_falign_loops_:
 857       align_loops = value;
 858       break;
 859
 860     case OPT_fargument_alias:
 861       flag_argument_noalias = !value;
 862       break;
 863
 864     case OPT_fargument_noalias:
 865       flag_argument_noalias = value;
 866       break;
 867
 868     case OPT_fargument_noalias_global:
 869       flag_argument_noalias = value + value;
 870       break;
 871
 872     case OPT_fasynchronous_unwind_tables:
 873       flag_asynchronous_unwind_tables = value;
 874       break;
 875
 876     case OPT_fbounds_check:
 877       flag_bounds_check = value;
 878       break;
 879
 880     case OPT_fbranch_count_reg:
 881       flag_branch_on_count_reg = value;
 882       break;
 883
 884     case OPT_fbranch_probabilities:
 885       flag_branch_probabilities = value;
 886       break;
 887
 888     case OPT_fbranch_target_load_optimize:
 889       flag_branch_target_load_optimize = value;
 890       break;
 891
 892     case OPT_fbranch_target_load_optimize2:
 893       flag_branch_target_load_optimize2 = value;
 894       break;
 895
 896     case OPT_fcall_used_:
 897       fix_register (arg, 0, 1);
 898       break;
 899
 900     case OPT_fcall_saved_:
 901       fix_register (arg, 0, 0);
 902       break;
 903
 904     case OPT_fcaller_saves:
 905       flag_caller_saves = value;
 906       break;
 907
 908     case OPT_fcommon:
 909       flag_no_common = !value;
 910       break;
 911
 912     case OPT_fcprop_registers:
 913       flag_cprop_registers = value;
 914       break;
 915
 916     case OPT_fcrossjumping:
 917       flag_crossjumping = value;
 918       break;
 919
 920     case OPT_fcse_follow_jumps:
 921       flag_cse_follow_jumps = value;
 922       break;
 923
 924     case OPT_fcse_skip_blocks:
 925       flag_cse_skip_blocks = value;
 926       break;
 927
 928     case OPT_fdata_sections:
 929       flag_data_sections = value;
 930       break;
 931
 932     case OPT_fdefer_pop:
 933       flag_defer_pop = value;
 934       break;
 935
 936     case OPT_fdelayed_branch:
 937       flag_delayed_branch = value;
 938       break;
 939
 940     case OPT_fdelete_null_pointer_checks:
 941       flag_delete_null_pointer_checks = value;
 942       break;
 943
 944     case OPT_fdiagnostics_show_location_:
 945       if (!strcmp (arg, "once"))
 946         diagnostic_prefixing_rule (global_dc) = DIAGNOSTICS_SHOW_PREFIX_ONCE;
 947       else if (!strcmp (arg, "every-line"))
 948         diagnostic_prefixing_rule (global_dc)
 949           = DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE;
 950       else
 951         return 0;
 952       break;
 953
 954     case OPT_fdump_unnumbered:
 955       flag_dump_unnumbered = value;
 956       break;
 957
 958     case OPT_feliminate_dwarf2_dups:
 959       flag_eliminate_dwarf2_dups = value;
 960       break;
 961
 962     case OPT_feliminate_unused_debug_types:
 963       flag_eliminate_unused_debug_types = value;
 964       break;
 965
 966     case OPT_feliminate_unused_debug_symbols:
 967       flag_debug_only_used_symbols = value;
 968       break;
 969
 970     case OPT_fexceptions:
 971       flag_exceptions = value;
 972       break;
 973
 974     case OPT_fexpensive_optimizations:
 975       flag_expensive_optimizations = value;
 976       break;
 977
 978     case OPT_ffast_math:
 979       set_fast_math_flags (value);
 980       break;
 981
 982     case OPT_ffinite_math_only:
 983       flag_finite_math_only = value;
 984       break;
 985
 986     case OPT_ffixed_:
 987       fix_register (arg, 1, 1);
 988       break;
 989
 990     case OPT_ffunction_cse:
 991       flag_no_function_cse = !value;
 992       break;
 993
 994     case OPT_ffloat_store:
 995       flag_float_store = value;
 996       break;
 997
 998     case OPT_fforce_addr:
 999       flag_force_addr = value;
1000       break;
1001
1002     case OPT_fforce_mem:
1003       flag_force_mem = value;
1004       break;
1005
1006     case OPT_ffunction_sections:
1007       flag_function_sections = value;
1008       break;
1009
1010     case OPT_fgcse:
1011       flag_gcse = value;
1012       break;
1013
1014     case OPT_fgcse_lm:
1015       flag_gcse_lm = value;
1016       break;
1017
1018     case OPT_fgcse_sm:
1019       flag_gcse_sm = value;
1020       break;
1021
1022     case OPT_fgcse_las:
1023       flag_gcse_las = value;
1024       break;
1025
1026     case OPT_fgnu_linker:
1027       flag_gnu_linker = value;
1028       break;
1029
1030     case OPT_fguess_branch_probability:
1031       flag_guess_branch_prob = value;
1032       break;
1033
1034     case OPT_fident:
1035       flag_no_ident = !value;
1036       break;
1037
1038     case OPT_fif_conversion:
1039       flag_if_conversion = value;
1040       break;
1041
1042     case OPT_fif_conversion2:
1043       flag_if_conversion2 = value;
1044       break;
1045
1046     case OPT_finhibit_size_directive:
1047       flag_inhibit_size_directive = value;
1048       break;
1049
1050     case OPT_finline:
1051       flag_no_inline = !value;
1052       break;
1053
1054     case OPT_finline_functions:
1055       flag_inline_functions = value;
1056       break;
1057
1058     case OPT_finline_limit_:
1059     case OPT_finline_limit_eq:
1060       set_param_value ("max-inline-insns-single", value / 2);
1061       set_param_value ("max-inline-insns-auto", value / 2);
1062       set_param_value ("max-inline-insns-rtl", value);
1063       break;
1064
1065     case OPT_finstrument_functions:
1066       flag_instrument_function_entry_exit = value;
1067       break;
1068
1069     case OPT_fkeep_inline_functions:
1070       flag_keep_inline_functions =value;
1071       break;
1072
1073     case OPT_fkeep_static_consts:
1074       flag_keep_static_consts = value;
1075       break;
1076
1077     case OPT_fleading_underscore:
1078       flag_leading_underscore = value;
1079       break;
1080
1081     case OPT_floop_optimize:
1082       flag_loop_optimize = value;
1083       break;
1084
1085     case OPT_fmath_errno:
1086       flag_errno_math = value;
1087       break;
1088
1089     case OPT_fmem_report:
1090       mem_report = value;
1091       break;
1092
1093     case OPT_fmerge_all_constants:
1094       flag_merge_constants = value + value;
1095       break;
1096
1097     case OPT_fmerge_constants:
1098       flag_merge_constants = value;
1099       break;
1100
1101     case OPT_fmessage_length_:
1102       pp_set_line_maximum_length (global_dc->printer, value);
1103       break;
1104
1105     case OPT_fmove_all_movables:
1106       flag_move_all_movables = value;
1107       break;
1108
1109     case OPT_fnew_ra:
1110       flag_new_regalloc = value;
1111       break;
1112
1113     case OPT_fnon_call_exceptions:
1114       flag_non_call_exceptions = value;
1115       break;
1116
1117     case OPT_fold_unroll_all_loops:
1118       flag_old_unroll_all_loops = value;
1119       break;
1120
1121     case OPT_fold_unroll_loops:
1122       flag_old_unroll_loops = value;
1123       break;
1124
1125     case OPT_fomit_frame_pointer:
1126       flag_omit_frame_pointer = value;
1127       break;
1128
1129     case OPT_foptimize_register_move:
1130       flag_regmove = value;
1131       break;
1132
1133     case OPT_foptimize_sibling_calls:
1134       flag_optimize_sibling_calls = value;
1135       break;
1136
1137     case OPT_fpack_struct:
1138       flag_pack_struct = value;
1139       break;
1140
1141     case OPT_fpeel_loops:
1142       flag_peel_loops = value;
1143       break;
1144
1145     case OPT_fpcc_struct_return:
1146       flag_pcc_struct_return = value;
1147       break;
1148
1149     case OPT_fpeephole:
1150       flag_no_peephole = !value;
1151       break;
1152
1153     case OPT_fpeephole2:
1154       flag_peephole2 = value;
1155       break;
1156
1157     case OPT_fpic:
1158       flag_pic = value;
1159       break;
1160
1161     case OPT_fpie:
1162       flag_pie = value;
1163       break;
1164
1165     case OPT_fprefetch_loop_arrays:
1166       flag_prefetch_loop_arrays = value;
1167       break;
1168
1169     case OPT_fprofile:
1170       profile_flag = value;
1171       break;
1172
1173     case OPT_fprofile_arcs:
1174       profile_arc_flag = value;
1175       break;
1176
1177     case OPT_fprofile_values:
1178       flag_profile_values = value;
1179       break;
1180
1181     case OPT_fvpt:
1182       flag_value_profile_transformations = value;
1183       break;
1184
1185     case OPT_frandom_seed:
1186       /* The real switch is -fno-random-seed.  */
1187       if (value)
1188         return 0;
1189       flag_random_seed = NULL;
1190       break;
1191
1192     case OPT_frandom_seed_:
1193       flag_random_seed = arg;
1194       break;
1195
1196     case OPT_freduce_all_givs:
1197       flag_reduce_all_givs = value;
1198       break;
1199
1200     case OPT_freg_struct_return:
1201       flag_pcc_struct_return = !value;
1202       break;
1203
1204     case OPT_fregmove:
1205       flag_regmove = value;
1206       break;
1207
1208     case OPT_frename_registers:
1209       flag_rename_registers = value;
1210       break;
1211
1212     case OPT_freorder_blocks:
1213       flag_reorder_blocks = value;
1214       break;
1215
1216     case OPT_freorder_functions:
1217       flag_reorder_functions = value;
1218       break;
1219
1220     case OPT_frerun_cse_after_loop:
1221       flag_rerun_cse_after_loop = value;
1222       break;
1223
1224     case OPT_frerun_loop_opt:
1225       flag_rerun_loop_opt = value;
1226       break;
1227
1228     case OPT_frounding_math:
1229       flag_rounding_math = value;
1230       break;
1231
1232     case OPT_fsched_interblock:
1233       flag_schedule_interblock = value;
1234       break;
1235
1236     case OPT_fsched_spec:
1237       flag_schedule_speculative = value;
1238       break;
1239
1240     case OPT_fsched_spec_load:
1241       flag_schedule_speculative_load = value;
1242       break;
1243
1244     case OPT_fsched_spec_load_dangerous:
1245       flag_schedule_speculative_load_dangerous = value;
1246       break;
1247
1248     case OPT_fsched_verbose_:
1249 #ifdef INSN_SCHEDULING
1250       fix_sched_param ("verbose", arg);
1251       break;
1252 #else
1253       return 0;
1254 #endif
1255
1256     case OPT_fsched2_use_superblocks:
1257       flag_sched2_use_superblocks = value;
1258       break;
1259
1260     case OPT_fsched2_use_traces:
1261       flag_sched2_use_traces = value;
1262       break;
1263
1264     case OPT_fschedule_insns:
1265       flag_schedule_insns = value;
1266       break;
1267
1268     case OPT_fschedule_insns2:
1269       flag_schedule_insns_after_reload = value;
1270       break;
1271
1272     case OPT_fsched_stalled_insns:
1273       flag_sched_stalled_insns = value;
1274       break;
1275
1276     case OPT_fsched_stalled_insns_:
1277       flag_sched_stalled_insns = value;
1278       if (flag_sched_stalled_insns == 0)
1279         flag_sched_stalled_insns = -1;
1280       break;
1281
1282     case OPT_fsched_stalled_insns_dep:
1283       flag_sched_stalled_insns_dep = 1;
1284       break;
1285
1286     case OPT_fsched_stalled_insns_dep_:
1287       flag_sched_stalled_insns_dep = value;
1288       break;
1289
1290     case OPT_fshared_data:
1291       flag_shared_data = value;
1292       break;
1293
1294     case OPT_fsignaling_nans:
1295       flag_signaling_nans = value;
1296       break;
1297
1298     case OPT_fsingle_precision_constant:
1299       flag_single_precision_constant = value;
1300       break;
1301
1302     case OPT_fstack_check:
1303       flag_stack_check = value;
1304       break;
1305
1306     case OPT_fstack_limit:
1307       /* The real switch is -fno-stack-limit.  */
1308       if (value)
1309         return 0;
1310       stack_limit_rtx = NULL_RTX;
1311       break;
1312
1313     case OPT_fstack_limit_register_:
1314       {
1315         int reg = decode_reg_name (arg);
1316         if (reg < 0)
1317           error ("unrecognized register name \"%s\"", arg);
1318         else
1319           stack_limit_rtx = gen_rtx_REG (Pmode, reg);
1320       }
1321       break;
1322
1323     case OPT_fstack_limit_symbol_:
1324       stack_limit_rtx = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (arg));
1325       break;
1326
1327     case OPT_fstrength_reduce:
1328       flag_strength_reduce = value;
1329       break;
1330
1331     case OPT_fstrict_aliasing:
1332       flag_strict_aliasing = value;
1333       break;
1334
1335     case OPT_fsyntax_only:
1336       flag_syntax_only = value;
1337       break;
1338
1339     case OPT_ftest_coverage:
1340       flag_test_coverage = value;
1341       break;
1342
1343     case OPT_fthread_jumps:
1344       flag_thread_jumps = value;
1345       break;
1346
1347     case OPT_ftime_report:
1348       time_report = value;
1349       break;
1350
1351     case OPT_ftls_model_:
1352       if (!strcmp (arg, "global-dynamic"))
1353         flag_tls_default = TLS_MODEL_GLOBAL_DYNAMIC;
1354       else if (!strcmp (arg, "local-dynamic"))
1355         flag_tls_default = TLS_MODEL_LOCAL_DYNAMIC;
1356       else if (!strcmp (arg, "initial-exec"))
1357         flag_tls_default = TLS_MODEL_INITIAL_EXEC;
1358       else if (!strcmp (arg, "local-exec"))
1359         flag_tls_default = TLS_MODEL_LOCAL_EXEC;
1360       else
1361         warning ("unknown tls-model \"%s\"", arg);
1362       break;
1363
1364     case OPT_ftracer:
1365       flag_tracer = value;
1366       break;
1367
1368     case OPT_ftrapping_math:
1369       flag_trapping_math = value;
1370       break;
1371
1372     case OPT_ftrapv:
1373       flag_trapv = value;
1374       break;
1375
1376     case OPT_funit_at_a_time:
1377       flag_unit_at_a_time = value;
1378       break;
1379
1380     case OPT_funroll_all_loops:
1381       flag_unroll_all_loops = value;
1382       break;
1383
1384     case OPT_funroll_loops:
1385       flag_unroll_loops = value;
1386       break;
1387
1388     case OPT_funsafe_math_optimizations:
1389       flag_unsafe_math_optimizations = value;
1390       break;
1391
1392     case OPT_funswitch_loops:
1393       flag_unswitch_loops = value;
1394       break;
1395
1396     case OPT_funwind_tables:
1397       flag_unwind_tables = value;
1398       break;
1399
1400     case OPT_fverbose_asm:
1401       flag_verbose_asm = value;
1402       break;
1403
1404     case OPT_fweb:
1405       flag_web = value;
1406       break;
1407
1408     case OPT_fwrapv:
1409       flag_wrapv = value;
1410       break;
1411
1412     case OPT_fwritable_strings:
1413       flag_writable_strings = value;
1414       break;
1415
1416     case OPT_fzero_initialized_in_bss:
1417       flag_zero_initialized_in_bss = value;
1418       break;
1419
1420     case OPT_g:
1421       set_debug_level (NO_DEBUG, DEFAULT_GDB_EXTENSIONS, arg);
1422       break;
1423
1424     case OPT_gcoff:
1425       set_debug_level (SDB_DEBUG, false, arg);
1426       break;
1427
1428     case OPT_gdwarf:
1429       if (*arg)
1430         {
1431           error ("use -gdwarf -gN for DWARF v1 level N, "
1432                  "and -gdwarf-2 for DWARF v2" );
1433           break;
1434         }
1435
1436       /* Fall through.  */
1437     case OPT_gdwarf_:
1438       set_debug_level (DWARF_DEBUG, code == OPT_gdwarf_, arg);
1439       break;
1440
1441     case OPT_gdwarf_2:
1442       set_debug_level (DWARF2_DEBUG, false, arg);
1443       break;
1444
1445     case OPT_ggdb:
1446       set_debug_level (NO_DEBUG, 2, arg);
1447       break;
1448
1449     case OPT_gstabs:
1450     case OPT_gstabs_:
1451       set_debug_level (DBX_DEBUG, code == OPT_gstabs_, arg);
1452       break;
1453
1454     case OPT_gvms:
1455       set_debug_level (VMS_DEBUG, false, arg);
1456       break;
1457
1458     case OPT_gxcoff:
1459     case OPT_gxcoff_:
1460       set_debug_level (XCOFF_DEBUG, code == OPT_gxcoff_, arg);
1461       break;
1462
1463     case OPT_m:
1464       set_target_switch (arg);
1465       break;
1466
1467     case OPT_o:
1468       asm_file_name = arg;
1469       break;
1470
1471     case OPT_p:
1472       profile_flag = 1;
1473       break;
1474
1475     case OPT_pedantic:
1476       pedantic = 1;
1477       break;
1478
1479     case OPT_pedantic_errors:
1480       flag_pedantic_errors = pedantic = 1;
1481       break;
1482
1483     case OPT_quiet:
1484       quiet_flag = 1;
1485       break;
1486
1487     case OPT_version:
1488       version_flag = 1;
1489       break;
1490
1491     case OPT_w:
1492       inhibit_warnings = true;
1493       break;
1494     }
1495
1496   return 1;
1497 }
1498
1499 /* Handle --param NAME=VALUE.  */
1500 static void
1501 handle_param (const char *carg)
1502 {
1503   char *equal, *arg;
1504   int value;
1505
1506   arg = xstrdup (carg);
1507   equal = strchr (arg, '=');
1508   if (!equal)
1509     error ("%s: --param arguments should be of the form NAME=VALUE", arg);
1510   else
1511     {
1512       value = integral_argument (equal + 1);
1513       if (value == -1)
1514         error ("invalid --param value `%s'", equal + 1);
1515       else
1516         {
1517           *equal = '\0';
1518           set_param_value (arg, value);
1519         }
1520     }
1521
1522   free (arg);
1523 }
1524
1525 /* Handle -W and -Wextra.  */
1526 static void
1527 set_Wextra (int setting)
1528 {
1529   extra_warnings = setting;
1530   warn_unused_value = setting;
1531   warn_unused_parameter = (setting && maybe_warn_unused_parameter);
1532
1533   /* We save the value of warn_uninitialized, since if they put
1534      -Wuninitialized on the command line, we need to generate a
1535      warning about not using it without also specifying -O.  */
1536   if (setting == 0)
1537     warn_uninitialized = 0;
1538   else if (warn_uninitialized != 1)
1539     warn_uninitialized = 2;
1540 }
1541
1542 /* Initialize unused warning flags.  */
1543 void
1544 set_Wunused (int setting)
1545 {
1546   warn_unused_function = setting;
1547   warn_unused_label = setting;
1548   /* Unused function parameter warnings are reported when either
1549      ``-Wextra -Wunused'' or ``-Wunused-parameter'' is specified.
1550      Thus, if -Wextra has already been seen, set warn_unused_parameter;
1551      otherwise set maybe_warn_extra_parameter, which will be picked up
1552      by set_Wextra.  */
1553   maybe_warn_unused_parameter = setting;
1554   warn_unused_parameter = (setting && extra_warnings);
1555   warn_unused_variable = setting;
1556   warn_unused_value = setting;
1557 }
1558
1559 /* The following routines are useful in setting all the flags that
1560    -ffast-math and -fno-fast-math imply.  */
1561 void
1562 set_fast_math_flags (int set)
1563 {
1564   flag_trapping_math = !set;
1565   flag_unsafe_math_optimizations = set;
1566   flag_finite_math_only = set;
1567   flag_errno_math = !set;
1568   if (set)
1569     {
1570       flag_signaling_nans = 0;
1571       flag_rounding_math = 0;
1572     }
1573 }
1574
1575 /* Return true iff flags are set as if -ffast-math.  */
1576 bool
1577 fast_math_flags_set_p (void)
1578 {
1579   return (!flag_trapping_math
1580           && flag_unsafe_math_optimizations
1581           && flag_finite_math_only
1582           && !flag_errno_math);
1583 }
1584
1585 /* Handle a debug output -g switch.  EXTENDED is true or false to support
1586    extended output (2 is special and means "-ggdb" was given).  */
1587 static void
1588 set_debug_level (enum debug_info_type type, int extended, const char *arg)
1589 {
1590   static bool type_explicit;
1591
1592   use_gnu_debug_info_extensions = extended;
1593
1594   if (type == NO_DEBUG)
1595     {
1596       if (write_symbols == NO_DEBUG)
1597         {
1598           write_symbols = PREFERRED_DEBUGGING_TYPE;
1599
1600           if (extended == 2)
1601             {
1602 #ifdef DWARF2_DEBUGGING_INFO
1603               write_symbols = DWARF2_DEBUG;
1604 #elif defined DBX_DEBUGGING_INFO
1605               write_symbols = DBX_DEBUG;
1606 #endif
1607             }
1608
1609           if (write_symbols == NO_DEBUG)
1610             warning ("target system does not support debug output");
1611         }
1612     }
1613   else
1614     {
1615       /* Does it conflict with an already selected type?  */
1616       if (type_explicit && write_symbols != NO_DEBUG && type != write_symbols)
1617         error ("debug format \"%s\" conflicts with prior selection",
1618                debug_type_names[type]);
1619       write_symbols = type;
1620       type_explicit = true;
1621     }
1622
1623   /* A debug flag without a level defaults to level 2.  */
1624   if (*arg == '\0')
1625     {
1626       if (!debug_info_level)
1627         debug_info_level = 2;
1628     }
1629   else
1630     {
1631       debug_info_level = integral_argument (arg);
1632       if (debug_info_level == (unsigned int) -1)
1633         error ("unrecognised debug output level \"%s\"", arg);
1634       else if (debug_info_level > 3)
1635         error ("debug output level %s is too high", arg);
1636     }
1637 }
1638
1639 /* Output --help text.  */
1640 static void
1641 print_help (void)
1642 {
1643   size_t i;
1644   const char *p;
1645
1646   GET_ENVIRONMENT (p, "COLUMNS");
1647   if (p)
1648     {
1649       int value = atoi (p);
1650       if (value > 0)
1651         columns = value;
1652     }
1653
1654   puts (_("The following options are language-independent:\n"));
1655
1656   print_filtered_help (CL_COMMON);
1657   print_param_help ();
1658
1659   for (i = 0; lang_names[i]; i++)
1660     {
1661       printf (_("The %s front end recognizes the following options:\n\n"),
1662               lang_names[i]);
1663       print_filtered_help (1U << i);
1664     }
1665
1666   display_target_options ();
1667 }
1668
1669 /* Print the help for --param.  */
1670 static void
1671 print_param_help (void)
1672 {
1673   size_t i;
1674
1675   puts (_("The --param option recognizes the following as parameters:\n"));
1676
1677   for (i = 0; i < LAST_PARAM; i++)
1678     {
1679       const char *help = compiler_params[i].help;
1680       const char *param = compiler_params[i].option;
1681
1682       if (help == NULL || *help == '\0')
1683         help = undocumented_msg;
1684
1685       /* Get the translation.  */
1686       help = _(help);
1687
1688       wrap_help (help, param, strlen (param));
1689     }
1690
1691   putchar ('\n');
1692 }
1693
1694 /* Print help for a specific front-end, etc.  */
1695 static void
1696 print_filtered_help (unsigned int flag)
1697 {
1698   unsigned int i, len, filter, indent = 0;
1699   bool duplicates = false;
1700   const char *help, *opt, *tab;
1701   static char *printed;
1702
1703   if (flag == CL_COMMON)
1704     {
1705       filter = flag;
1706       if (!printed)
1707         printed = xmalloc (cl_options_count);
1708       memset (printed, 0, cl_options_count);
1709     }
1710   else
1711     {
1712       /* Don't print COMMON options twice.  */
1713       filter = flag | CL_COMMON;
1714
1715       for (i = 0; i < cl_options_count; i++)
1716         {
1717           if ((cl_options[i].flags & filter) != flag)
1718             continue;
1719
1720           /* Skip help for internal switches.  */
1721           if (cl_options[i].flags & CL_UNDOCUMENTED)
1722             continue;
1723
1724           /* Skip switches that have already been printed, mark them to be
1725              listed later.  */
1726           if (printed[i])
1727             {
1728               duplicates = true;
1729               indent = print_switch (cl_options[i].opt_text, indent);
1730             }
1731         }
1732
1733       if (duplicates)
1734         {
1735           putchar ('\n');
1736           putchar ('\n');
1737         }
1738     }
1739
1740   for (i = 0; i < cl_options_count; i++)
1741     {
1742       if ((cl_options[i].flags & filter) != flag)
1743         continue;
1744
1745       /* Skip help for internal switches.  */
1746       if (cl_options[i].flags & CL_UNDOCUMENTED)
1747         continue;
1748
1749       /* Skip switches that have already been printed.  */
1750       if (printed[i])
1751         continue;
1752
1753       printed[i] = true;
1754
1755       help = cl_options[i].help;
1756       if (!help)
1757         help = undocumented_msg;
1758
1759       /* Get the translation.  */
1760       help = _(help);
1761
1762       tab = strchr (help, '\t');
1763       if (tab)
1764         {
1765           len = tab - help;
1766           opt = help;
1767           help = tab + 1;
1768         }
1769       else
1770         {
1771           opt = cl_options[i].opt_text;
1772           len = strlen (opt);
1773         }
1774
1775       wrap_help (help, opt, len);
1776     }
1777
1778   putchar ('\n');
1779 }
1780
1781 /* Output ITEM, of length ITEM_WIDTH, in the left column, followed by
1782    word-wrapped HELP in a second column.  */
1783 static unsigned int
1784 print_switch (const char *text, unsigned int indent)
1785 {
1786   unsigned int len = strlen (text) + 1; /* trailing comma */
1787
1788   if (indent)
1789     {
1790       putchar (',');
1791       if (indent + len > columns)
1792         {
1793           putchar ('\n');
1794           putchar (' ');
1795           indent = 1;
1796         }
1797     }
1798   else
1799     putchar (' ');
1800
1801   putchar (' ');
1802   fputs (text, stdout);
1803
1804   return indent + len + 1;
1805 }
1806
1807 /* Output ITEM, of length ITEM_WIDTH, in the left column, followed by
1808    word-wrapped HELP in a second column.  */
1809 static void
1810 wrap_help (const char *help, const char *item, unsigned int item_width)
1811 {
1812   unsigned int col_width = 27;
1813   unsigned int remaining, room, len;
1814
1815   remaining = strlen (help);
1816
1817   do
1818     {
1819       room = columns - 3 - MAX (col_width, item_width);
1820       if (room > columns)
1821         room = 0;
1822       len = remaining;
1823
1824       if (room < len)
1825         {
1826           unsigned int i;
1827
1828           for (i = 0; help[i]; i++)
1829             {
1830               if (i >= room && len != remaining)
1831                 break;
1832               if (help[i] == ' ')
1833                 len = i;
1834               else if ((help[i] == '-' || help[i] == '/')
1835                        && help[i + 1] != ' '
1836                        && ISALPHA (help[i - 1]))
1837                 len = i + 1;
1838             }
1839         }
1840
1841       printf( "  %-*.*s %.*s\n", col_width, item_width, item, len, help);
1842       item_width = 0;
1843       while (help[len] == ' ')
1844         len++;
1845       help += len;
1846       remaining -= len;
1847     }
1848   while (remaining);
1849 }