gcc/opts-common.c

   1 /* Command line option handling.
   2    Copyright (C) 2006, 2007, 2008, 2010 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "intl.h"
  23 #include "coretypes.h"
  24 #include "opts.h"
  25 #include "options.h"
  26
  27 /* Perform a binary search to find which option the command-line INPUT
  28    matches.  Returns its index in the option array, and
  29    OPT_SPECIAL_unknown on failure.
  30
  31    This routine is quite subtle.  A normal binary search is not good
  32    enough because some options can be suffixed with an argument, and
  33    multiple sub-matches can occur, e.g. input of "-pedantic" matching
  34    the initial substring of "-pedantic-errors".
  35
  36    A more complicated example is -gstabs.  It should match "-g" with
  37    an argument of "stabs".  Suppose, however, that the number and list
  38    of switches are such that the binary search tests "-gen-decls"
  39    before having tested "-g".  This doesn't match, and as "-gen-decls"
  40    is less than "-gstabs", it will become the lower bound of the
  41    binary search range, and "-g" will never be seen.  To resolve this
  42    issue, 'optc-gen.awk' makes "-gen-decls" point, via the back_chain member,
  43    to "-g" so that failed searches that end between "-gen-decls" and
  44    the lexicographically subsequent switch know to go back and see if
  45    "-g" causes a match (which it does in this example).
  46
  47    This search is done in such a way that the longest match for the
  48    front end in question wins.  If there is no match for the current
  49    front end, the longest match for a different front end is returned
  50    (or N_OPTS if none) and the caller emits an error message.  */
  51 size_t
  52 find_opt (const char *input, int lang_mask)
  53 {
  54   size_t mn, mx, md, opt_len;
  55   size_t match_wrong_lang;
  56   int comp;
  57
  58   mn = 0;
  59   mx = cl_options_count;
  60
  61   /* Find mn such this lexicographical inequality holds:
  62      cl_options[mn] <= input < cl_options[mn + 1].  */
  63   while (mx - mn > 1)
  64     {
  65       md = (mn + mx) / 2;
  66       opt_len = cl_options[md].opt_len;
  67       comp = strncmp (input, cl_options[md].opt_text + 1, opt_len);
  68
  69       if (comp < 0)
  70         mx = md;
  71       else
  72         mn = md;
  73     }
  74
  75   /* This is the switch that is the best match but for a different
  76      front end, or OPT_SPECIAL_unknown if there is no match at all.  */
  77   match_wrong_lang = OPT_SPECIAL_unknown;
  78
  79   /* Backtrace the chain of possible matches, returning the longest
  80      one, if any, that fits best.  With current GCC switches, this
  81      loop executes at most twice.  */
  82   do
  83     {
  84       const struct cl_option *opt = &cl_options[mn];
  85
  86       /* Is the input either an exact match or a prefix that takes a
  87          joined argument?  */
  88       if (!strncmp (input, opt->opt_text + 1, opt->opt_len)
  89           && (input[opt->opt_len] == '\0' || (opt->flags & CL_JOINED)))
  90         {
  91           /* If language is OK, return it.  */
  92           if (opt->flags & lang_mask)
  93             return mn;
  94
  95           /* If we haven't remembered a prior match, remember this
  96              one.  Any prior match is necessarily better.  */
  97           if (match_wrong_lang == OPT_SPECIAL_unknown)
  98             match_wrong_lang = mn;
  99         }
 100
 101       /* Try the next possibility.  This is cl_options_count if there
 102          are no more.  */
 103       mn = opt->back_chain;
 104     }
 105   while (mn != cl_options_count);
 106
 107   /* Return the best wrong match, or OPT_SPECIAL_unknown if none.  */
 108   return match_wrong_lang;
 109 }
 110
 111 /* If ARG is a non-negative integer made up solely of digits, return its
 112    value, otherwise return -1.  */
 113
 114 int
 115 integral_argument (const char *arg)
 116 {
 117   const char *p = arg;
 118
 119   while (*p && ISDIGIT (*p))
 120     p++;
 121
 122   if (*p == '\0')
 123     return atoi (arg);
 124
 125   return -1;
 126 }
 127
 128 /* Decode the switch beginning at ARGV for the language indicated by
 129    LANG_MASK, into the structure *DECODED.  Returns the number of
 130    switches consumed.  */
 131
 132 static unsigned int
 133 decode_cmdline_option (const char **argv, unsigned int lang_mask,
 134                        struct cl_decoded_option *decoded)
 135 {
 136   size_t opt_index;
 137   const char *opt, *arg = 0;
 138   char *dup = 0;
 139   int value = 1;
 140   unsigned int result = 1;
 141   const struct cl_option *option;
 142   int errors = 0;
 143
 144   opt = argv[0];
 145
 146   opt_index = find_opt (opt + 1, lang_mask | CL_COMMON | CL_TARGET);
 147   if (opt_index == OPT_SPECIAL_unknown
 148       && (opt[1] == 'W' || opt[1] == 'f' || opt[1] == 'm')
 149       && opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-')
 150     {
 151       /* Drop the "no-" from negative switches.  */
 152       size_t len = strlen (opt) - 3;
 153
 154       dup = XNEWVEC (char, len + 1);
 155       dup[0] = '-';
 156       dup[1] = opt[1];
 157       memcpy (dup + 2, opt + 5, len - 2 + 1);
 158       opt = dup;
 159       value = 0;
 160       opt_index = find_opt (opt + 1, lang_mask | CL_COMMON | CL_TARGET);
 161     }
 162
 163   if (opt_index == OPT_SPECIAL_unknown)
 164     {
 165       arg = argv[0];
 166       goto done;
 167     }
 168
 169   option = &cl_options[opt_index];
 170
 171   /* Reject negative form of switches that don't take negatives as
 172      unrecognized.  */
 173   if (!value && (option->flags & CL_REJECT_NEGATIVE))
 174     {
 175       opt_index = OPT_SPECIAL_unknown;
 176       arg = argv[0];
 177       goto done;
 178     }
 179
 180   /* Check to see if the option is disabled for this configuration.  */
 181   if (option->flags & CL_DISABLED)
 182     errors |= CL_ERR_DISABLED;
 183
 184   /* Sort out any argument the switch takes.  */
 185   if (option->flags & CL_JOINED)
 186     {
 187       /* Have arg point to the original switch.  This is because
 188          some code, such as disable_builtin_function, expects its
 189          argument to be persistent until the program exits.  */
 190       arg = argv[0] + cl_options[opt_index].opt_len + 1;
 191       if (!value)
 192         arg += strlen ("no-");
 193
 194       if (*arg == '\0' && !(option->flags & CL_MISSING_OK))
 195         {
 196           if (option->flags & CL_SEPARATE)
 197             {
 198               arg = argv[1];
 199               result = 2;
 200               if (arg == NULL)
 201                 result = 1;
 202             }
 203           else
 204             /* Missing argument.  */
 205             arg = NULL;
 206         }
 207     }
 208   else if (option->flags & CL_SEPARATE)
 209     {
 210       arg = argv[1];
 211       result = 2;
 212       if (arg == NULL)
 213         result = 1;
 214     }
 215
 216   /* Check if this is a switch for a different front end.  */
 217   if (!(option->flags & (lang_mask | CL_COMMON | CL_TARGET)))
 218     errors |= CL_ERR_WRONG_LANG;
 219   else if ((option->flags & CL_TARGET)
 220            && (option->flags & CL_LANG_ALL)
 221            && !(option->flags & lang_mask))
 222     /* Complain for target flag language mismatches if any languages
 223        are specified.  */
 224       errors |= CL_ERR_WRONG_LANG;
 225
 226   if (arg == NULL && (option->flags & (CL_JOINED | CL_SEPARATE)))
 227     errors |= CL_ERR_MISSING_ARG;
 228
 229   /* If the switch takes an integer, convert it.  */
 230   if (arg && (option->flags & CL_UINTEGER))
 231     {
 232       value = integral_argument (arg);
 233       if (value == -1)
 234         errors |= CL_ERR_UINT_ARG;
 235     }
 236
 237  done:
 238   if (dup)
 239     free (dup);
 240   decoded->opt_index = opt_index;
 241   decoded->arg = arg;
 242   decoded->value = value;
 243   decoded->errors = errors;
 244   switch (result)
 245     {
 246     case 1:
 247       decoded->orig_option_with_args_text = argv[0];
 248       break;
 249     case 2:
 250       decoded->orig_option_with_args_text = concat (argv[0], " ",
 251                                                     argv[1], NULL);
 252       break;
 253     default:
 254       gcc_unreachable ();
 255     }
 256   return result;
 257 }
 258
 259 /* Decode command-line options (ARGC and ARGV being the arguments of
 260    main) into an array, setting *DECODED_OPTIONS to a pointer to that
 261    array and *DECODED_OPTIONS_COUNT to the number of entries in the
 262    array.  The first entry in the array is always one for the program
 263    name (OPT_SPECIAL_program_name).  LANG_MASK indicates the language
 264    applicable for decoding.  Do not produce any diagnostics or set
 265    state outside of these variables.  */
 266
 267 void
 268 decode_cmdline_options_to_array (unsigned int argc, const char **argv,
 269                                  unsigned int lang_mask,
 270                                  struct cl_decoded_option **decoded_options,
 271                                  unsigned int *decoded_options_count)
 272 {
 273   unsigned int n, i;
 274   struct cl_decoded_option *opt_array;
 275   unsigned int num_decoded_options;
 276
 277   opt_array = XNEWVEC (struct cl_decoded_option, argc);
 278
 279   opt_array[0].opt_index = OPT_SPECIAL_program_name;
 280   opt_array[0].arg = argv[0];
 281   opt_array[0].orig_option_with_args_text = argv[0];
 282   opt_array[0].value = 1;
 283   opt_array[0].errors = 0;
 284   num_decoded_options = 1;
 285
 286   for (i = 1; i < argc; i += n)
 287     {
 288       const char *opt = argv[i];
 289
 290       /* Interpret "-" or a non-switch as a file name.  */
 291       if (opt[0] != '-' || opt[1] == '\0')
 292         {
 293           opt_array[num_decoded_options].opt_index = OPT_SPECIAL_input_file;
 294           opt_array[num_decoded_options].arg = opt;
 295           opt_array[num_decoded_options].orig_option_with_args_text = opt;
 296           opt_array[num_decoded_options].value = 1;
 297           opt_array[num_decoded_options].errors = 0;
 298           num_decoded_options++;
 299           n = 1;
 300           continue;
 301         }
 302
 303       n = decode_cmdline_option (argv + i, lang_mask,
 304                                  &opt_array[num_decoded_options]);
 305       num_decoded_options++;
 306     }
 307
 308   opt_array = XRESIZEVEC (struct cl_decoded_option, opt_array,
 309                           num_decoded_options);
 310   *decoded_options = opt_array;
 311   *decoded_options_count = num_decoded_options;
 312 }
 313
 314 /* Return true if NEXT_OPT_IDX cancels OPT_IDX.  Return false if the
 315    next one is the same as ORIG_NEXT_OPT_IDX.  */
 316
 317 static bool
 318 cancel_option (int opt_idx, int next_opt_idx, int orig_next_opt_idx)
 319 {
 320   /* An option can be canceled by the same option or an option with
 321      Negative.  */
 322   if (cl_options [next_opt_idx].neg_index == opt_idx)
 323     return true;
 324
 325   if (cl_options [next_opt_idx].neg_index != orig_next_opt_idx)
 326     return cancel_option (opt_idx, cl_options [next_opt_idx].neg_index,
 327                           orig_next_opt_idx);
 328
 329   return false;
 330 }
 331
 332 /* Filter out options canceled by the ones after them.  */
 333
 334 void
 335 prune_options (int *argcp, char ***argvp)
 336 {
 337   int argc = *argcp;
 338   int *options = XNEWVEC (int, argc);
 339   /* We will only return this replacement argv if we remove at least
 340      one argument, so it does not need to be size (argc + 1) to
 341      make room for the terminating NULL because we will always have
 342      freed up at least one slot when we end up using it at all.  */
 343   char **argv = XNEWVEC (char *, argc);
 344   int i, arg_count, need_prune = 0;
 345   const struct cl_option *option;
 346   size_t opt_index;
 347
 348   /* Scan all arguments.  */
 349   for (i = 1; i < argc; i++)
 350     {
 351       int value = 1;
 352       const char *opt = (*argvp) [i];
 353
 354       opt_index = find_opt (opt + 1, -1);
 355       if (opt_index == OPT_SPECIAL_unknown
 356           && (opt[1] == 'W' || opt[1] == 'f' || opt[1] == 'm')
 357           && opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-')
 358         {
 359           char *dup;
 360
 361           /* Drop the "no-" from negative switches.  */
 362           size_t len = strlen (opt) - 3;
 363
 364           dup = XNEWVEC (char, len + 1);
 365           dup[0] = '-';
 366           dup[1] = opt[1];
 367           memcpy (dup + 2, opt + 5, len - 2 + 1);
 368           opt = dup;
 369           value = 0;
 370           opt_index = find_opt (opt + 1, -1);
 371           free (dup);
 372         }
 373
 374       if (opt_index == OPT_SPECIAL_unknown)
 375         {
 376 cont:
 377           options [i] = 0;
 378           continue;
 379         }
 380
 381       option = &cl_options[opt_index];
 382       if (option->neg_index < 0)
 383         goto cont;
 384
 385       /* Skip joined switches.  */
 386       if ((option->flags & CL_JOINED))
 387         goto cont;
 388
 389       /* Reject negative form of switches that don't take negatives as
 390          unrecognized.  */
 391       if (!value && (option->flags & CL_REJECT_NEGATIVE))
 392         goto cont;
 393
 394       options [i] = (int) opt_index;
 395       need_prune |= options [i];
 396     }
 397
 398   if (!need_prune)
 399     goto done;
 400
 401   /* Remove arguments which are negated by others after them.  */
 402   argv [0] = (*argvp) [0];
 403   arg_count = 1;
 404   for (i = 1; i < argc; i++)
 405     {
 406       int j, opt_idx;
 407
 408       opt_idx = options [i];
 409       if (opt_idx)
 410         {
 411           int next_opt_idx;
 412           for (j = i + 1; j < argc; j++)
 413             {
 414               next_opt_idx = options [j];
 415               if (next_opt_idx
 416                   && cancel_option (opt_idx, next_opt_idx,
 417                                     next_opt_idx))
 418                 break;
 419             }
 420         }
 421       else
 422         goto keep;
 423
 424       if (j == argc)
 425         {
 426 keep:
 427           argv [arg_count] = (*argvp) [i];
 428           arg_count++;
 429         }
 430     }
 431
 432   if (arg_count != argc)
 433     {
 434       *argcp = arg_count;
 435       *argvp = argv;
 436       /* Add NULL-termination.  Guaranteed not to overflow because
 437          arg_count here can only be less than argc.  */
 438       argv[arg_count] = 0;
 439     }
 440   else
 441     {
 442 done:
 443       free (argv);
 444     }
 445
 446   free (options);
 447 }