usr/src/tools/scripts/interface_cmp.pl

   1 #!/usr/bin/perl -w
   2 #
   3 # CDDL HEADER START
   4 #
   5 # The contents of this file are subject to the terms of the
   6 # Common Development and Distribution License (the "License").
   7 # You may not use this file except in compliance with the License.
   8 #
   9 # You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10 # or http://www.opensolaris.org/os/licensing.
  11 # See the License for the specific language governing permissions
  12 # and limitations under the License.
  13 #
  14 # When distributing Covered Code, include this CDDL HEADER in each
  15 # file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16 # If applicable, add the following below this CDDL HEADER, with the
  17 # fields enclosed by brackets "[]" replaced with your own identifying
  18 # information: Portions Copyright [yyyy] [name of copyright owner]
  19 #
  20 # CDDL HEADER END
  21 #
  22
  23 #
  24 # Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
  25 #
  26
  27 #
  28 # interface_cmp audits two interface definition files (as created by
  29 # interface_check) against one another, and confirms that:
  30 #
  31 #  o    All versioned libraries that were present in the previous interface
  32 #       are present in the new interface
  33 #
  34 #  o    for each non-private interface in a library confirm that no symbols
  35 #       have been removed and that no symbols have been added to it between
  36 #       the two revisions
  37 #
  38 # Return codes:
  39 #
  40 #  0    All interfaces in the new release are identical in old release.
  41 #  1    Something is different refer to the error messages.
  42
  43
  44 use strict;
  45
  46 use POSIX qw(getenv);
  47 use Getopt::Std;
  48 use File::Basename;
  49
  50 #### Define all global variables (required for strict)
  51 use vars  qw($Prog);
  52 use vars  qw(%opt);
  53 use vars  qw(%old_hash %old_alias %new_hash %new_alias);
  54
  55 # Exception Arrays:
  56 #
  57 # The ADDSYM and DELSYM exceptions are maintained on the @AddSymList
  58 # and @DelSymList arrays, respectively. Each array element is a reference
  59 # to a subarray of triples:
  60 #       (sym_re, ver_re, obj_re)
  61 # where each item in the tripple is a regular expression, used to
  62 # match a particular symbol/version/object combination.
  63 #
  64 # The EMPTY_TOPVERSION exceptions are maintained on the @EmptyTopVerList
  65 # array. Each array element is a reference to a subarray of pairs:
  66 #       (ver_re, obj_re)
  67 # where each item in the pair is a regular expression, used to
  68 # match a particular version/object combination.
  69 #
  70 use vars  qw(@AddSymList @DelSymList @EmptyTopVerList);
  71
  72
  73 ## LoadExceptions
  74 #
  75 # Locate the exceptions file and process its contents. We can't use
  76 # onbld_elfmod::LoadExceptionsToEXRE() for this, because our exceptions
  77 # need to support more than a single regular expression.
  78 #
  79 # exit:
  80 #       @AddSymList, @DelSymList, and @EmptyTopVerList have been updated
  81 #
  82 # note:
  83 #       We expand strings of the form MACH(dir) to match the given
  84 #       directory as well as any 64-bit architecture subdirectory that
  85 #       might be present (i.e. amd64, sparcv9).
  86 #
  87 sub LoadExceptions {
  88         my $file;
  89         my $Line;
  90         my $LineNum = 0;
  91         my $err = 0;
  92
  93         # Locate the exception file
  94         FILE: {
  95                 # If -e is specified, that file must be used
  96                 if ($opt{e}) {
  97                         $file = $opt{e};
  98                         last FILE;
  99                 }
 100
 101                 # If this is an activated workspace, use the exception
 102                 # file found in the exceptions_list directory.
 103                 if (defined($ENV{CODEMGR_WS})) {
 104                         $file = "$ENV{CODEMGR_WS}/exception_lists/interface_cmp";
 105                         last FILE if (-f $file);
 106                 }
 107
 108                 # As a final backstop, the SUNWonbld package provides a
 109                 # copy of the exception file. This can be useful if we
 110                 # are being used with an older workspace.
 111                 #
 112                 # This script is installed in the SUNWonbld bin directory,
 113                 # while the exception file is in etc/exception_lists. Find
 114                 # it relative to the script location given by $0.
 115                 $file = dirname($0) . "/../etc/exception_lists/interface_cmp";
 116                 last FILE if (-f $file);
 117
 118                 # No exception file was found.
 119                 return;
 120         }
 121
 122         open (EFILE, $file) ||
 123                 die "$Prog: unable to open exceptions file: $file";
 124         while ($Line = onbld_elfmod::GetLine(\*EFILE, \$LineNum)) {
 125
 126                 # Expand MACH()
 127                 $Line =~ s/MACH\(([^)]+)\)/$1(\/amd64|\/sparcv9)?/g;
 128
 129                 if ($Line =~ /^DELSYM\s+/) {
 130                     my ($item, $sym_re, $ver_re, $obj_re) =
 131                         split(/\s+/, $Line, 4);
 132                     push @DelSymList, [ $sym_re, $ver_re, $obj_re ];
 133                     next;
 134                 }
 135
 136                 if ($Line =~ /^ADDSYM\s+/) {
 137                     my ($item, $sym_re, $ver_re, $obj_re) =
 138                         split(/\s+/, $Line, 4);
 139                     push @AddSymList, [ $sym_re, $ver_re, $obj_re ];
 140                     next;
 141                 }
 142
 143                 if ($Line =~ /^EMPTY_TOPVERSION\s+/) {
 144                     my ($item, $ver_re, $obj_re) = split(/\s+/, $Line, 3);
 145                     push @EmptyTopVerList, [ $ver_re, $obj_re ];
 146                     next;
 147                 }
 148
 149                 $err++;
 150                 printf(STDERR "$file: Unrecognized option: ".
 151                     "line $LineNum: $Line\n");
 152         }
 153         close EFILE;
 154
 155         exit 1 if ($err != 0);
 156 }
 157
 158 ## ExSym(SymList, sym, ver, obj)
 159 #
 160 # Compare a given symbol/version/object combination against the
 161 # exceptions found in the given list.
 162 #
 163 # entry:
 164 #       SymList - Reference to @AddSymList, or @DelSymList.
 165 #       sym, ver, obj - Combination to be compared against exception list
 166 #
 167 # exit:
 168 #       Returns True (1) if there is a match, and False (0) otherwise.
 169 #
 170 sub ExSym {
 171         my ($SymList, $sym, $ver, $obj) = @_;
 172
 173         foreach my $ex (@$SymList) {
 174                 return 1 if ($obj =~ /$$ex[2]/) && ($ver =~ /$$ex[1]/) &&
 175                     ($sym =~ /$$ex[0]/);
 176         }
 177
 178         return 0;
 179 }
 180
 181 ## ExTopVer(ver, obj)
 182 #
 183 # Compare a given version/object combination against the pairs found
 184 # in @EmptyTopVerList.
 185 #
 186 # entry:
 187 #       ver, obj - Combination to be compared against empty top version list
 188 #
 189 # exit:
 190 #       Returns True (1) if there is a match, and False (0) otherwise.
 191 #
 192 sub ExTopVer {
 193         my ($ver, $obj) = @_;
 194
 195         foreach my $ex (@EmptyTopVerList) {
 196                 return 1 if ($obj =~ /$$ex[1]/) && ($ver =~ /$$ex[0]/);
 197         }
 198
 199         return 0;
 200 }
 201
 202 ## ExpandInheritance(objhashref)
 203 #
 204 # For each version contained in the specified object hash reference,
 205 # add the inherited symbols.
 206 #
 207 sub ExpandInheritance {
 208         my $obj = $_[0];
 209
 210         # Versions to process. Typically, inheriting versions come before
 211         # the versions they inherit. Processing the list in reverse order
 212         # maximizes the odds that a needed sub-version will have already
 213         # have been processed.
 214         my @vers = reverse(@{$obj->{'VERSION_NAMES'}});
 215
 216         # Versions to process in the next pass
 217         my @next_vers = ();
 218
 219         # Hash, indexed by version name, that reflects whether the version
 220         # has been expanded yet or not.
 221         my %done = ();
 222
 223         while (scalar(@vers) > 0) {
 224                 foreach my $name (@vers) {
 225                         my $i;
 226                         my $defer = 0;
 227                         my $cur_version = $obj->{'VERSION_INFO'}{$name};
 228                         my ($top, $direct, $total, $symhash, $inheritarr) =
 229                             @{$cur_version};
 230
 231                         # In order to expand this version, all the inherited
 232                         # versions must already have been done. If not, put
 233                         # this version on @next_vers for the next pass.
 234                         my $num = scalar(@$inheritarr);
 235                         for ($i = 0; $i < $num; $i++) {
 236                             if (!$done{$inheritarr->[$i]}) {
 237                                 $defer = 1;
 238                                 push @next_vers, $name;
 239                                 last;
 240                             }
 241                         }
 242                         next if ($defer);
 243
 244                         # Add all the symbols from the inherited versions
 245                         # to this one.
 246                         for ($i = 0; $i < $num; $i++) {
 247                                 my $i_version =
 248                                     $obj->{'VERSION_INFO'}{$inheritarr->[$i]};
 249                                 my $i_symhash = $i_version->[3];
 250
 251                                 foreach my $sym (keys %$i_symhash) {
 252                                     if (!defined($cur_version->[3]{$sym})) {
 253                                             $cur_version->[2]++;
 254                                             $cur_version->[3]{$sym} = 'INHERIT';
 255                                     }
 256                                 }
 257                         }
 258
 259                         $done{$name} = 1;
 260                 }
 261
 262                 @vers = @next_vers;
 263                 @next_vers = ();
 264         }
 265 }
 266
 267 ## ReadInterface(file, alias)
 268 #
 269 # Read the interface description file, as produced by interface_check, and
 270 # return a hash describing it.
 271 #
 272 # entry:
 273 #       file - Interface file to read.
 274 #       alias - Refence to hash to be filled in with any aliases
 275 #               that are seen in the file. The alias name is the key,
 276 #               and the object is the value.
 277 #
 278 # exit:
 279 #       The hash referenced by alias has been updated.
 280 #
 281 #       The return value is a hash that encapsulates the interface
 282 #       information. This hash returned uses the object names as the
 283 #       key. Each key references a sub-hash that contains information
 284 #       for that object:
 285 #
 286 #       CLASS           -> ELFCLASS
 287 #       TYPE            -> ELF type
 288 #       VERSION_NAMES   -> Reference to array [1..n] of version names, in the
 289 #                          order they come from the input file.
 290 #       VERSION_INFO    -> Reference to hash indexed by version name, yielding
 291 #                          a reference to an array containing information about
 292 #                          that version.
 293 #
 294 #       The arrays referenced via VERSION_INFO are of the form:
 295 #
 296 #               (top, new, total, symhashref, inheritarrref)
 297 #
 298 #       where:
 299 #               top - 1 if version is a TOP_VERSION, 0 for a regular VERSION
 300 #               new - Number of symbols defined explicitly by version
 301 #               total - Number of symbols included in version, both new,
 302 #                       and via inheritance.
 303 #               symhashref - Reference to hash indexed by symbol names, and
 304 #                       yielding true (1).
 305 #               inheritarrref - Reference to array of names of versions
 306 #                       inherited by this one.
 307 #
 308 sub ReadInterface {
 309         my ($file, $alias) = @_;
 310         my %main_hash = ();
 311         my $Line;
 312         my $LineNum = 0;
 313         my $obj_name;
 314         my $obj_hash;
 315         my $sym_ok = 0;
 316         my $cur_version;
 317
 318         open(FILE, $file) || die "$Prog: Unable to open: $file";
 319
 320         # Until we see an OBJECT line, nothing else is valid. To
 321         # simplify the error handling, use a simple initial loop to
 322         # read the file up to that point
 323         while ($Line = onbld_elfmod::GetLine(\*FILE, \$LineNum)) {
 324                 if ($Line =~ s/^OBJECT\s+//i) {
 325                     $obj_name = $Line;
 326                     $main_hash{$obj_name} = {};
 327                     $obj_hash = $main_hash{$obj_name};
 328                     last;
 329                 }
 330                 die "$file: OBJECT expected on line $LineNum: $Line\n";
 331         }
 332
 333         # Read the remainder of the file
 334         while ($Line = onbld_elfmod::GetLine(\*FILE, \$LineNum)) {
 335                 # Items are parsed in order of decreasing frequency
 336
 337                 if ($Line =~
 338                     /^SYMBOL\s+([^\s]+)$/i) {
 339                         my $sym = $1;
 340
 341                         die "$file: SYMBOL not expected on line $LineNum: $Line\n"
 342                             if !$sym_ok;
 343
 344                         $cur_version->[1]++;
 345                         $cur_version->[2]++;
 346                         $cur_version->[3]{$sym} = 'NEW';
 347                         next;
 348                 }
 349
 350                 if ($Line =~ /^((TOP_)?VERSION)\s+([^\s]+)(\s+\{(.*)\})?\s*$/i) {
 351                         my ($top, $name, $inherit) = ($2, $3, $5);
 352
 353                         $top = defined($top) ? 1 : 0;
 354
 355                         my @inheritarr = defined($inherit) ?
 356                             split /[,{\s]+/, $inherit : ();
 357
 358                         $cur_version = [ $top, 0, 0, {}, \@inheritarr ];
 359                         $obj_hash->{'VERSION_INFO'}{$name} = $cur_version;
 360
 361                         push @{$obj_hash->{'VERSION_NAMES'}}, $name;
 362                         $sym_ok = 1;
 363                         next;
 364                 }
 365
 366                 if ($Line =~ /^OBJECT\s+([^\s]+)$/i) {
 367                     my $prev_obj_hash = $obj_hash;
 368                     $obj_name = $1;
 369                     $main_hash{$obj_name} = {};
 370                     $obj_hash = $main_hash{$obj_name};
 371
 372                     # Expand the versions for the object just processed
 373                     ExpandInheritance($prev_obj_hash);
 374                     next;
 375                 }
 376
 377                 if ($Line =~ /^CLASS\s+([^\s]+)$/i) {
 378                         $obj_hash->{'CLASS'} = $1;
 379                         next;
 380                 }
 381
 382                 if ($Line =~ /^TYPE\s+([^\s]+)$/i) {
 383                         $obj_hash->{'TYPE'} = $1;
 384                         next;
 385                 }
 386
 387                 if ($Line =~ /^ALIAS\s+([^\s]+)$/i) {
 388                         $$alias{$1} = $obj_name;
 389                         next;
 390                 }
 391
 392                 die "$file: unrecognized item on line $LineNum: $Line\n";
 393         }
 394         close FILE;
 395
 396         # Expand the versions for the final object from the file
 397         ExpandInheritance($obj_hash);
 398
 399         return %main_hash;
 400 }
 401
 402 ## PrintInterface(main_hash, alias)
 403 #
 404 # Dump the contents of main_hash and alias to stdout in the same format
 405 # used by interface_check to produce the input interface file. This output
 406 # should diff cleanly against the original (ignoring the header comments).
 407 #
 408 sub PrintInterface {
 409         my ($main_hash, $alias_hash) = @_;
 410
 411         foreach my $obj (sort keys %$main_hash) {
 412                 print "OBJECT\t$obj\n";
 413                 print "CLASS\t$main_hash->{$obj}{'CLASS'}\n";
 414                 print "TYPE\t$main_hash->{$obj}{'TYPE'}\n";
 415
 416                 # This is inefficient, but good enough for debugging
 417                 # Look at all the aliases and print those that belong
 418                 # to this object.
 419                 foreach my $alias (sort keys %$alias_hash) {
 420                         print "ALIAS\t$alias\n"
 421                             if ($obj eq $alias_hash->{$alias});
 422                 }
 423
 424                 next if !defined($main_hash->{$obj}{'VERSION_NAMES'});
 425
 426                 my $num = scalar(@{$main_hash->{$obj}{'VERSION_NAMES'}});
 427                 my $i;
 428                 for ($i = 0; $i < $num; $i++) {
 429                         my $name = $main_hash->{$obj}{'VERSION_NAMES'}[$i];
 430                         my ($top, $direct, $total, $symhash, $inheritarr) =
 431                             @{$main_hash->{$obj}{'VERSION_INFO'}{$name}};
 432
 433                         $top = $top ? "TOP_" : '';
 434
 435                         my $inherit = (scalar(@$inheritarr) > 0) ?
 436                             "\t{" . join(', ', @{$inheritarr}) . "}" : '';
 437
 438                         print "${top}VERSION\t$name$inherit\n";
 439
 440                         foreach my $sym (sort keys %$symhash) {
 441                                 print "\t$symhash->{$sym}\t$sym\n";
 442                         }
 443                 }
 444         }
 445 }
 446
 447 ## compare()
 448 #
 449 # Compare the old interface definition contained in (%old_hash, %old_alias)
 450 # with the new interface contained in (%new_hash, %new_alias).
 451 #
 452 sub compare {
 453         foreach my $old_obj (sort keys %old_hash) {
 454                 my $new_obj = $old_obj;
 455                 my $Ttl = 0;
 456
 457                 # If the object does not exist in the new interface,
 458                 # then see if there's an alias for it. Failing that,
 459                 # we simply ignore the object.
 460                 if (!defined($new_hash{$new_obj})) {
 461                         next if !defined($new_alias{$new_obj});
 462                         $new_obj = $new_alias{$new_obj};
 463                 }
 464
 465                 my $old = $old_hash{$old_obj};
 466                 my $new = $new_hash{$new_obj};
 467
 468                 # Every version in the old object must exist in the new object,
 469                 # and there must be exactly the same symbols in each.
 470                 my $num = scalar(@{$old->{'VERSION_NAMES'}});
 471                 for (my $i = 0; $i < $num; $i++) {
 472                         my $name = $old->{'VERSION_NAMES'}[$i];
 473
 474                         # New object must have this version
 475                         if (!defined($new->{'VERSION_INFO'}{$name})) {
 476                                 onbld_elfmod::OutMsg2(\*STDOUT, \$Ttl, $old_obj,
 477                                     $new_obj, "$name: deleted version");
 478                                 next;
 479                         }
 480
 481                         my ($old_top, $old_direct, $old_total, $old_symhash) =
 482                             @{$old->{'VERSION_INFO'}{$name}};
 483                         my ($new_top, $new_direct, $new_total, $new_symhash) =
 484                             @{$new->{'VERSION_INFO'}{$name}};
 485
 486                         # If this is an empty top version, and the old object
 487                         # has the EMPTY_TOPVERSION exception set, then we
 488                         # skip it as if it were not present.
 489                         next if $old_top && ($old_direct == 0) &&
 490                             ExTopVer($name, $old_obj);
 491
 492                         # We check that every symbol in the old object is
 493                         # in the new one to detect deleted symbols. We then
 494                         # check that every symbol in the new object is also
 495                         # in the old object, to find added symbols. If the
 496                         # "deleted" check is clean, and the two objects have
 497                         # the same number of symbols in their versions, then we
 498                         # can skip the "added" test, because we know that
 499                         # there is no room for an addition to have happened.
 500                         # Since most objects satisfy these constraints, we
 501                         # end up doing roughly half the number of comparisons
 502                         # that would otherwise be needed.
 503                         my $check_added_syms =
 504                             ($old_total == $new_total) ? 0: 1;
 505
 506                         # Every symbol in the old version must be in the new one
 507                         foreach my $sym (sort keys %$old_symhash) {
 508                                 if (!defined($new_symhash->{$sym})) {
 509                                         onbld_elfmod::OutMsg2(\*STDOUT,
 510                                            \$Ttl, $old_obj, $new_obj,
 511                                            "$name: deleted interface: $sym")
 512                                             if !ExSym(\@DelSymList,
 513                                                       $sym, $name, $new_obj);
 514                                         $check_added_syms = 1;
 515                                 }
 516                         }
 517
 518                         # Do the "added" check, unless we can optimize it away.
 519                         # Every symbol in the new version must be in the old one.
 520                         if ($check_added_syms) {
 521                                 foreach my $sym (sort keys %$new_symhash) {
 522                                     if (!defined($old_symhash->{$sym})) {
 523                                         next if ExSym(\@AddSymList,
 524                                             $sym, $name, $new_obj);
 525                                         onbld_elfmod::OutMsg2(\*STDOUT,
 526                                                \$Ttl, $old_obj, $new_obj,
 527                                                "$name: added interface: $sym");
 528                                     }
 529                                 }
 530                         }
 531
 532                         # We want to ensure that version numbers in an
 533                         # inheritance chain don't go up by more than 1 in
 534                         # any given release. If the version names are in the
 535                         # numbered <PREFIX>x.y[.z] format, we can compare the
 536                         # two top versions and see if this has happened.
 537                         #
 538                         # For a given <PREFIX>x.y[.z], valid sucessors would
 539                         # be <PREFIX>x.(y+1) or <PREFIX>x.y.(z+1), where z is
 540                         # assumed to be 0 if not present.
 541                         #
 542                         # This check only makes sense when the new interface
 543                         # is a direct decendent of the old one, as specified
 544                         # via the -d option. If the two interfaces are more
 545                         # than one release apart, we should not do this test.
 546                         next if !($opt{d} && $old_top && !$new_top);
 547
 548                         # Known numbered version?
 549                         #
 550                         # Key to @Cat contents:
 551                         # [0]   'NUMBERED'
 552                         # [1]   number of dot separated numeric fields. 2 or 3.
 553                         # [2]   prefix
 554                         # [3]   major #
 555                         # [4]   minor #
 556                         # [5]   micro # (only if [1] is 3)
 557                         my @Cat = onbld_elfmod_vertype::Category($name, '');
 558                         next if ($Cat[0] ne 'NUMBERED');
 559
 560                         my $iname1 = "$Cat[2]$Cat[3]." . ($Cat[4] + 1);
 561                         my $iname2;
 562                         if ($Cat[1] == 3) {
 563                             $iname2 = "$Cat[2]$Cat[3].$Cat[4]." . ($Cat[5] + 1);
 564                         } else {
 565                             $iname2 = "$Cat[2]$Cat[3].$Cat[4].1";
 566                         }
 567
 568                         if (defined($new->{'VERSION_INFO'}{$iname1}) ||
 569                             defined($new->{'VERSION_INFO'}{$iname2})) {
 570                                 my $i_top =
 571                                     $new->{'VERSION_INFO'}{$iname1}[0] ||
 572                                     $new->{'VERSION_INFO'}{$iname2}[0];
 573                                 if (!$i_top) {
 574                                         onbld_elfmod::OutMsg2(\*STDOUT,
 575                                             \$Ttl, $old_obj, $new_obj,
 576                                             "$name: inconsistant " .
 577                                             "version increment: " .
 578                                             "expect $iname1 or $iname2 ".
 579                                             "to replace top version");
 580                                 }
 581                         } else {
 582                                 onbld_elfmod::OutMsg2(\*STDOUT,
 583                                     \$Ttl, $old_obj, $new_obj,
 584                                     "$name: expected superseding " .
 585                                     "top version to $name not " .
 586                                     "present: $iname1 or $iname2");
 587                         }
 588                 }
 589
 590
 591                 # Empty versions in the established interface description
 592                 # are usually the result of fixing a versioning mistake
 593                 # at some point in the past. These versions are part of
 594                 # the public record, and cannot be changed now. However, if
 595                 # comparing two interface descriptions from the same gate,
 596                 # flag any empty versions in the new interface description
 597                 # that are not present in the old one. These have yet to
 598                 # become part of the official interface, and should be removed
 599                 # before they do.
 600                 next if !$opt{d};
 601
 602                 $num = scalar(@{$new->{'VERSION_NAMES'}});
 603                 for (my $i = 0; $i < $num; $i++) {
 604                         my $name = $new->{'VERSION_NAMES'}[$i];
 605
 606                         # If old object has this version, skip it
 607                         next if defined($old->{'VERSION_INFO'}{$name});
 608
 609                         # If explicitly whitelisted, skip it
 610                         next if ExTopVer($name, $new_obj);
 611
 612                         my ($new_top, $new_direct, $new_total, $new_symhash) =
 613                             @{$new->{'VERSION_INFO'}{$name}};
 614
 615                         if ($new_direct == 0) {
 616                                 onbld_elfmod::OutMsg2(\*STDOUT,
 617                                     \$Ttl, $old_obj, $new_obj,
 618                                     "$name: invalid empty new version");
 619                         }
 620                 }
 621         }
 622
 623 }
 624
 625
 626
 627 # -----------------------------------------------------------------------------
 628
 629 # Establish a program name for any error diagnostics.
 630 chomp($Prog = `basename $0`);
 631
 632 # Check that we have arguments. Normally, 2 plain arguments are required,
 633 # but if -t is present, only one is allowed.
 634 if ((getopts('c:de:ot', \%opt) == 0) || (scalar(@ARGV) != ($opt{t} ? 1 : 2))) {
 635         print "usage: $Prog [-dot] [-c vtype_mod] [-e exfile] old new\n";
 636         print "\t[-c vtype_mod]\tsupply alternative version category module\n";
 637         print "\t[-d]\t\tnew is a direct decendent of old\n";
 638         print "\t[-e exfile]\texceptions file\n";
 639         print "\t[-o]\t\tproduce one-liner output (prefixed with pathname)\n";
 640         print "\t[-t]\tParse old, and recreate to stdout\n";
 641         exit 1;
 642 }
 643
 644 # We depend on the onbld_elfmod and onbld_elfmod_vertype perl modules.
 645 # Both modules are maintained in the same directory as this script,
 646 # and are installed in ../lib/perl. Use the local one if present,
 647 # and the installed one otherwise.
 648 #
 649 # The caller is allowed to supply an alternative implementation for
 650 # onbld_elfmod_vertype via the -c option. In this case, the alternative
 651 # implementation is expected to provide the same interface as the standard
 652 # copy, and is loaded instead.
 653 #
 654 my $moddir = my $vermoddir = dirname($0);
 655 $moddir = "$moddir/../lib/perl" if ! -f "$moddir/onbld_elfmod.pm";
 656 require "$moddir/onbld_elfmod.pm";
 657 if ($opt{c}) {
 658         require "$opt{c}";
 659 } else {
 660         $vermoddir = "$vermoddir/../lib/perl"
 661             if ! -f "$vermoddir/onbld_elfmod_vertype.pm";
 662         require "$vermoddir/onbld_elfmod_vertype.pm";
 663 }
 664
 665 # Locate and process the exceptions file
 666 LoadExceptions();
 667
 668 %old_alias = ();
 669 %old_hash = ReadInterface($ARGV[0], \%old_alias);
 670
 671 # If -t is present, only one argument is allowed --- we parse it, and then
 672 # print the same information back to stderr in the same format as the original.
 673 # This is useful for debugging, to verify that the parsing is correct.
 674 if ($opt{t}) {
 675         PrintInterface(\%old_hash, \%old_alias);
 676         exit 0;
 677 }
 678
 679 %new_alias = ();
 680 %new_hash = ReadInterface($ARGV[1], \%new_alias);
 681
 682 compare();
 683
 684 exit 0;