nsz Git - libfirm/blob - ir/be/scripts/generate_regalloc_if.pl

   1 #!/usr/bin/perl -w
   2
   3 # This script generates C code which emits assembler code for the
   4 # assembler ir nodes. It takes a "emit" key from the node specification
   5 # and substitutes lines starting with . with a corresponding fprintf().
   6 # Creation: 2005/11/14
   7 # $Id$
   8
   9 use strict;
  10 use Data::Dumper;
  11
  12 my $specfile   = $ARGV[0];
  13 my $target_dir = $ARGV[1];
  14
  15 our $arch;
  16 our %reg_classes;
  17 our %nodes;
  18
  19 # include spec file
  20
  21 my $return;
  22
  23 no strict "subs";
  24 unless ($return = do $specfile) {
  25         warn "couldn't parse $specfile: $@" if $@;
  26         warn "couldn't do $specfile: $!"    unless defined $return;
  27         warn "couldn't run $specfile"       unless $return;
  28 }
  29 use strict "subs";
  30
  31 my $target_c   = $target_dir."/gen_".$arch."_regalloc_if.c";
  32 my $target_h   = $target_dir."/gen_".$arch."_regalloc_if.h";
  33 my $target_h_t = $target_dir."/gen_".$arch."_regalloc_if_t.h";
  34
  35 # helper function
  36 sub translate_reg_type {
  37         my $t = shift;
  38
  39         if ($t == 0) {
  40                 return "arch_register_type_none";
  41         }
  42         else {
  43                 my @types;
  44
  45                 if ($t & 1) {
  46                         push(@types, "arch_register_type_caller_save");
  47                 }
  48
  49                 if ($t & 2) {
  50                         push(@types, "arch_register_type_callee_save");
  51                 }
  52
  53                 if ($t & 4) {
  54                         push(@types, "arch_register_type_ignore");
  55                 }
  56
  57                 return join(" | ", @types);
  58         }
  59 }
  60
  61 # stacks for output
  62 my @obst_regtypes;     # stack for the register type variables
  63 my @obst_regclasses;   # stack for the register class variables
  64 my @obst_classdef;     # stack to define a name for a class index
  65 my @obst_regdef;       # stack to define a name for a register index
  66 my @obst_reginit;      # stack for the register type inits
  67 my @obst_req;          # stack for the register requirements
  68 my @obst_limit_func;   # stack for functions to return a subset of a register class
  69 my @obst_defreq_head;  # stack for prototypes of default requirement function
  70 my @obst_header_all;   # stack for some extern struct defs needed for bearch_$arch include
  71 my @obst_requirement_def;  # stack for requirement name defines
  72
  73 my $numregs;
  74 my $class_ptr;
  75 my $class_idx = 0;
  76
  77 my $tmp;
  78
  79 my %reg2class;
  80
  81 # there is a default NONE requirement
  82 $tmp = "/* Default NONE register requirements */\n";
  83 $tmp .= "const $arch\_register_req_t $arch\_default_req_none = {\n";
  84 $tmp .= "  {\n";
  85 $tmp .= "    arch_register_req_type_none,  /* register type  */\n";
  86 $tmp .= "    NULL,                         /* register class */\n";
  87 $tmp .= "    NULL,                         /* limit function */\n";
  88 $tmp .= "    NULL,                         /* limit environment */\n";
  89 $tmp .= "    NULL,                         /* node for same */\n";
  90 $tmp .= "    NULL                          /* node for different */\n";
  91 $tmp .= "  },\n";
  92 $tmp .= "  0,                              /* same pos */\n";
  93 $tmp .= "  0                               /* different pos */\n";
  94 $tmp .= "};\n\n";
  95 push(@obst_req, $tmp);
  96 push(@obst_header_all, "extern const $arch\_register_req_t $arch\_default_req_none;\n");
  97
  98 push(@obst_classdef, "#define N_CLASSES ".scalar(keys(%reg_classes))."\n");
  99
 100 my $class_mode;
 101
 102 # generate register type and class variable, init function and default requirements
 103 foreach my $class_name (keys(%reg_classes)) {
 104         my @class         = @{ $reg_classes{"$class_name"} };
 105         my $old_classname = $class_name;
 106
 107         $class_name = $arch."_".$class_name;
 108         $numregs    = "N_".$class_name."_REGS";
 109         $class_ptr  = "&".$arch."_reg_classes[CLASS_".$class_name."]";
 110         $class_mode = pop(@class)->{"mode"};
 111
 112         push(@obst_regtypes, "#define $numregs ".($#class + 1)."\n");
 113         push(@obst_regtypes, "arch_register_t ".$class_name."_regs[$numregs];\n\n");
 114
 115         push(@obst_classdef, "#define CLASS_$class_name $class_idx\n");
 116         push(@obst_regclasses, "{ \"$class_name\", $numregs, NULL, ".$class_name."_regs }");
 117
 118         # there is a default NORMAL requirement for each class
 119         $tmp  = "/* Default NORMAL register requirements for class $class_name */\n";
 120         $tmp .= "const $arch\_register_req_t $arch\_default_req_$class_name = {\n";
 121         $tmp .= "  {\n";
 122         $tmp .= "    arch_register_req_type_normal,\n";
 123         $tmp .= "    $class_ptr,\n";
 124         $tmp .= "    NULL,                    /* limit function */ \n";
 125         $tmp .= "    NULL,                    /* limit environment */\n";
 126         $tmp .= "    NULL,                    /* node for same */\n";
 127         $tmp .= "    NULL                     /* node for different */\n";
 128         $tmp .= "  },\n";
 129         $tmp .= "  0,                         /* same pos */\n";
 130         $tmp .= "  0                          /* different pos */\n";
 131         $tmp .= "};\n\n";
 132         push(@obst_req, $tmp);
 133         push(@obst_header_all, "extern const $arch\_register_req_t $arch\_default_req_$class_name;\n");
 134
 135         my $idx = 0;
 136         push(@obst_reginit, "  /* Init of all registers in class '$class_name' */\n\n");
 137         push(@obst_reginit, "  /* set largest possible mode for '$class_name' */\n");
 138         push(@obst_reginit, "  $arch\_reg_classes[CLASS_".$class_name."].mode = $class_mode;\n\n");
 139         foreach (@class) {
 140                 # For each class we build for each of it's member registers a limit function
 141                 # which limits the class to this particular register. We also build the
 142                 # corresponding requirement structs.
 143                 # We need those functions to set register requirements on demand in transformation
 144                 # esp. for Call and RegParams where we can mix int and float parameters.
 145
 146                 my $limit_func_name = $arch."_limit_".$class_name."_".$_->{"name"};
 147
 148                 # push the function prototype
 149                 $tmp = "void $limit_func_name(void *_unused, bitset_t *bs)";
 150                 push(@obst_defreq_head, $tmp.";\n");
 151
 152                 # push the function definition
 153                 $tmp .= " {\n";
 154                 $tmp .= "    bs = bitset_clear_all(bs);\n";
 155                 $tmp .= "    bitset_set(bs, REG_".uc($_->{"name"}).");\n";  # REGISTER to index assignment is done some lines down
 156                 $tmp .= "}\n\n";
 157                 push(@obst_limit_func, $tmp);
 158
 159                 # push the default requirement struct
 160                 $tmp  = "const $arch\_register_req_t $arch\_default_req_$class_name\_".$_->{"name"}." = {\n";
 161                 $tmp .= "  {\n";
 162                 $tmp .= "    arch_register_req_type_limited,\n";
 163                 $tmp .= "    $class_ptr,\n";
 164                 $tmp .= "    $limit_func_name,\n";
 165                 $tmp .= "    NULL,                     /* limit environment */\n";
 166                 $tmp .= "    NULL,                     /* node for same */\n";
 167                 $tmp .= "    NULL                      /* node for different */\n";
 168                 $tmp .= "  },\n";
 169                 $tmp .= "  0,                          /* same pos */\n";
 170                 $tmp .= "  0                           /* different pos */\n";
 171                 $tmp .= "};\n\n";
 172                 push(@obst_req, $tmp);
 173                 push(@obst_header_all,"extern const $arch\_register_req_t $arch\_default_req_$class_name\_".$_->{"name"}.";\n");
 174
 175                 $reg2class{$_->{"name"}} = { "class" => $old_classname, "index" => $idx }; # remember reg to class for later use
 176                 push(@obst_regdef, "#define REG_".uc($_->{"name"})." $idx\n");
 177                 push(@obst_reginit, "  ".$class_name."_regs[$idx].name      = \"".$_->{"name"}."\";\n");
 178                 push(@obst_reginit, "  ".$class_name."_regs[$idx].reg_class = $class_ptr;\n");
 179                 push(@obst_reginit, "  ".$class_name."_regs[$idx].index     = $idx;\n");
 180                 push(@obst_reginit, "  ".$class_name."_regs[$idx].type      = ".translate_reg_type($_->{"type"}).";\n");
 181                 push(@obst_reginit, "\n");
 182                 $idx++;
 183         }
 184
 185         $class_idx++;
 186 }
 187
 188 # generate node-register constraints
 189 foreach my $op (keys(%nodes)) {
 190         my %n = %{ $nodes{"$op"} };
 191
 192         next if (!exists($n{"reg_req"}));
 193
 194         $op = $arch."_".$op;
 195
 196         push(@obst_req, "/* IN requirements for '$op' */\n");
 197         # check for argument requirements
 198         if (exists($n{"reg_req"}{"in"})) {
 199                 generate_requirements(\%n, $op, "in");
 200         }
 201
 202         push(@obst_req, "/* OUT requirements for '$op' */\n");
 203         # check for result requirements
 204         if (exists($n{"reg_req"}{"out"})) {
 205                 generate_requirements(\%n, $op, "out");
 206         }
 207 }
 208
 209
 210
 211 # generate header _t (internal usage) file
 212 open(OUT, ">$target_h_t") || die("Could not open $target_h_t, reason: $!\n");
 213
 214 my $creation_time = localtime(time());
 215
 216 $tmp = uc($arch);
 217
 218 print OUT<<EOF;
 219 #ifndef _GEN_$tmp\_REGALLOC_IF_T_H_
 220 #define _GEN_$tmp\_REGALLOC_IF_T_H_
 221
 222 /**
 223  * Generated register classes from spec.
 224  *
 225  * DO NOT EDIT THIS FILE, your changes will be lost.
 226  * Edit $specfile instead.
 227  * created by: $0 $specfile $target_dir
 228  * date:       $creation_time
 229  */
 230
 231 EOF
 232
 233 print OUT @obst_requirement_def;
 234
 235 print OUT "\n#endif /* _GEN_$tmp\_REGALLOC_IF_T_H_ */\n";
 236
 237
 238
 239 # generate header (external usage) file
 240 open(OUT, ">$target_h") || die("Could not open $target_h, reason: $!\n");
 241
 242 $creation_time = localtime(time());
 243
 244 print OUT<<EOF;
 245 #ifndef _GEN_$tmp\_REGALLOC_IF_H_
 246 #define _GEN_$tmp\_REGALLOC_IF_H_
 247
 248 /**
 249  * Contains additional external requirements defs for external includes.
 250  *
 251  * DO NOT EDIT THIS FILE, your changes will be lost.
 252  * Edit $specfile instead.
 253  * created by: $0 $specfile $target_dir
 254  * date:       $creation_time
 255  */
 256
 257 #include "../bearch.h"
 258 #include "$arch\_nodes_attr.h"
 259
 260 EOF
 261
 262 print OUT @obst_regdef, "\n";
 263
 264 print OUT @obst_classdef, "\n";
 265
 266 print OUT @obst_regtypes, "\n";
 267
 268 print OUT "extern arch_register_class_t $arch\_reg_classes[N_CLASSES];\n\n";
 269
 270 print OUT "void ".$arch."_register_init(void *isa_ptr);\n\n";
 271
 272 print OUT @obst_header_all, "\n";
 273
 274 print OUT @obst_defreq_head, "\n";
 275
 276 print OUT "\n#endif /* _GEN_$tmp\_REGALLOC_IF_H_ */\n";
 277
 278 close(OUT);
 279
 280
 281
 282 # generate c inline file
 283 open(OUT, ">$target_c") || die("Could not open $target_c, reason: $!\n");
 284
 285 $creation_time = localtime(time());
 286
 287 print OUT<<EOF;
 288 /**
 289  * The generated interface for the register allocator.
 290  * Contains register classes and types and register constraints
 291  * for all nodes where constraints were given in spec.
 292  *
 293  * DO NOT EDIT THIS FILE, your changes will be lost.
 294  * Edit $specfile instead.
 295  * created by: $0 $specfile $target_dir
 296  * date:       $creation_time
 297  */
 298
 299 #include "gen_$arch\_regalloc_if.h"
 300 #include "bearch_$arch\_t.h"   /* we need this to put the caller saved registers into the isa set */
 301 #include "$arch\_map_regs.h"
 302 #include "irmode.h"
 303
 304 EOF
 305
 306 print OUT "arch_register_class_t $arch\_reg_classes[] = {\n  ".join(",\n  ", @obst_regclasses)."\n};\n\n";
 307
 308 print OUT "void ".$arch."_register_init(void *isa_ptr) {\n";
 309 print OUT @obst_reginit;
 310 print OUT "}\n\n";
 311
 312 print OUT @obst_limit_func;
 313
 314 print OUT @obst_req;
 315
 316 close(OUT);
 317
 318 ###
 319 # Remember the register class for each index in the given requirements.
 320 # We need this information for requirements like "in_sX" or "out_dX"
 321 # @return array of classes corresponding to the requirement for each index
 322 ###
 323 sub build_inout_idx_class {
 324         my $n     = shift;
 325         my $op    = shift;
 326         my $inout = shift;
 327         my @idx_class;
 328
 329         if (exists($n->{"reg_req"}{"$inout"})) {
 330                 my @reqs = @{ $n->{"reg_req"}{"$inout"} };
 331
 332                 for (my $idx = 0; $idx <= $#reqs; $idx++) {
 333                         my $class = undef;
 334
 335                         if ($reqs[$idx] eq "none") {
 336                                 $class = "none";
 337                         }
 338                         elsif (is_reg_class($reqs[$idx])) {
 339                                 $class = $reqs[$idx];
 340                         }
 341                         else {
 342                                 my @regs = split(/ /, $reqs[$idx]);
 343 GET_CLASS:              foreach my $reg (@regs) {
 344                                         if ($reg =~ /!?(in|out)\_r\d+/) {
 345                                                 $class = "UNKNOWN_CLASS";
 346                                         }
 347                                         else {
 348                                                 $class = get_reg_class($reg);
 349                                                 if (!defined $class) {
 350                                                         die("Could not get ".uc($inout)." register class for '$op' pos $idx (reg $reg) ... exiting.\n");
 351                                                 }
 352                                                 else {
 353                                                         last GET_CLASS;
 354                                                 } # !defined class
 355                                         } # if (reg =~ ...
 356                                 } # foreach
 357                         } # if
 358
 359                         push(@idx_class, $class);
 360                 } # for
 361         } # if
 362
 363         return @idx_class;
 364 }
 365
 366 ###
 367 # Generates the requirements for the given description
 368 ###
 369 sub generate_requirements {
 370         my $n     = shift;
 371         my $op    = shift;
 372         my $inout = shift;
 373
 374         # get classes for the complementary direction
 375         my $outin     = ($inout eq "in") ? "out" : "in";
 376
 377         my @reqs = @{ $n->{"reg_req"}{"$inout"} };
 378
 379         for (my $idx = 0; $idx <= $#reqs; $idx++) {
 380                 my $class = undef;
 381
 382                 my $tmp2 = "const $arch\_register_req_t _".$op."_reg_req_$inout\_$idx = ";
 383                 my $tmp  = "#define ".$op."_reg_req_$inout\_$idx ";
 384
 385                 if ($reqs[$idx] eq "none") {
 386                         $tmp .= "&$arch\_default_req_none\n";
 387                 }
 388                 elsif ($reqs[$idx] =~ /^new_reg_(.*)$/) {
 389                         if (is_reg_class($1)) {
 390                                 $tmp  .=  "&_".$op."_reg_req_$inout\_$idx\n";
 391                                 $tmp2 .= "{\n";
 392                                 $tmp2 .= "  {\n";
 393                                 $tmp2 .= "    arch_register_req_type_should_be_different_from_all,\n";
 394                                 $tmp2 .= "    &$arch\_reg_classes[CLASS_$arch\_".$1."],\n";
 395                                 $tmp2 .= "    NULL,        /* limit function */\n";
 396                                 $tmp2 .= "    NULL,        /* limit environment */\n";
 397                                 $tmp2 .= "    NULL,        /* same node */\n";
 398                                 $tmp2 .= "    NULL         /* different node */\n";
 399                                 $tmp2 .= "  },\n";
 400                                 $tmp2 .= "  0,\n";
 401                                 $tmp2 .= "  0\n";
 402                                 $tmp2 .= "};\n";
 403
 404                                 push(@obst_req, $tmp2."\n");
 405                                 push(@obst_header_all, "extern const $arch\_register_req_t _".$op."_reg_req_$inout\_$idx;\n");
 406                         }
 407                         else {
 408                                 print STDERR "Invalid register class '$1' given in OUT requirement $idx for '$op'.\n";
 409                         }
 410                 }
 411                 elsif (is_reg_class($reqs[$idx])) {
 412                         $tmp .= "&$arch\_default_req_".$arch."_".$reqs[$idx]."\n";
 413                 }
 414                 else {
 415                         my @req_type_mask;
 416                         my ($class, $has_limit, $same_pos, $different_pos) = build_subset_class_func($n, $op, $idx, (($inout eq "in") ? 1 : 0), $reqs[$idx]);
 417
 418                         if (!defined($class)) {
 419                                 die("Could not build subset for ".uc($inout)." requirements '$op' pos $idx ... exiting.\n");
 420                         }
 421
 422                         if ($has_limit) {
 423                                 push(@req_type_mask, "arch_register_req_type_limited");
 424                         }
 425                         if (defined($same_pos)) {
 426                                 push(@req_type_mask, "arch_register_req_type_should_be_same");
 427                         }
 428                         if (defined($different_pos)) {
 429                                 push(@req_type_mask, "arch_register_req_type_should_be_different");
 430                         }
 431
 432                         $tmp  .= "&_".$op."_reg_req_$inout\_$idx\n";
 433                         $tmp2 .= "{\n";
 434                         $tmp2 .= "  {\n";
 435                         $tmp2 .= "    ".join(" | ", @req_type_mask).",\n";
 436                         $tmp2 .= "    &$arch\_reg_classes[CLASS_$arch\_".$class."],\n";
 437                         $tmp2 .= "    ".($has_limit ? "limit_reg_".$op."_$inout\_".$idx : "NULL").",\n";
 438                         $tmp2 .= "    NULL,        /* limit environment */\n";
 439                         $tmp2 .= "    NULL,        /* same node */\n";
 440                         $tmp2 .= "    NULL         /* different node */\n";
 441                         $tmp2 .= "  },\n";
 442                         $tmp2 .= "  ".(defined($same_pos) ? $same_pos : "0").",\n";
 443                         $tmp2 .= "  ".(defined($different_pos) ? $different_pos : "0")."\n";
 444                         $tmp2 .= "};\n";
 445
 446                         push(@obst_req, $tmp2."\n");
 447                         push(@obst_header_all, "extern const $arch\_register_req_t _".$op."_reg_req_$inout\_$idx;\n");
 448                 }
 449
 450                 push(@obst_requirement_def, $tmp);
 451         }
 452
 453 }
 454
 455 ###
 456 # Determines whether $name is a specified register class or not.
 457 # @return 1 if name is register class, 0 otherwise
 458 ###
 459 sub is_reg_class {
 460         my $name = shift;
 461         return 1 if exists($reg_classes{"$name"});
 462         return 0;
 463 }
 464
 465 ###
 466 # Returns the register class for a given register.
 467 # @return class or undef
 468 ###
 469 sub get_reg_class {
 470         my $reg = shift;
 471         $reg = substr($reg, 1) if ($reg =~ /!.*/);
 472         return $reg2class{"$reg"}{"class"} if (exists($reg2class{"$reg"}));
 473         return undef;
 474 }
 475
 476 ###
 477 # Returns the index of a given register within it's register class.
 478 # @return index or undef
 479 ###
 480 sub get_reg_index {
 481         my $reg = shift;
 482         return $reg2class{"$reg"}{"index"} if (exists($reg2class{"$reg"}));
 483         return undef;
 484 }
 485
 486 ###
 487 # Generates the function for a given $op and a given IN-index
 488 # which returns a subset of possible register from a register class
 489 # @return classname from which the subset is derived or undef and
 490 #         pos which corresponds to in/out reference position or undef
 491 ###
 492 sub build_subset_class_func {
 493         my $neg           = undef;
 494         my $class         = undef;
 495         my $has_limit     = 0;
 496         my $same_pos      = undef;
 497         my $different_pos = undef;
 498         my $temp;
 499         my @temp_obst;
 500
 501
 502         # build function header
 503         my $n   = shift;
 504         my $op  = shift;
 505         my $idx = shift;
 506         my $in  = shift;
 507
 508         my $outin = $in ? "out" : "in";
 509         my @regs  = split(/ /, shift);
 510
 511         my @idx_class = build_inout_idx_class($n, $op, $outin);
 512
 513         # set/unset registers
 514 CHECK_REQS: foreach (@regs) {
 515                 if (/(!)?$outin\_r(\d+)/) {
 516                         if (($1 && defined($different_pos)) || (!$1 && defined($same_pos))) {
 517                                 print STDERR "Multiple in/out references of same type in one requirement not allowed.\n";
 518                                 return (undef, undef, undef, undef);
 519                         }
 520
 521                         if ($1) {
 522                                 $different_pos = $in ? -$2 : $2 - 1;
 523                         }
 524                         else {
 525                                 $same_pos = $in ? -$2 : $2 - 1;
 526                         }
 527
 528                         $class = $idx_class[$2 - 1];
 529                         next CHECK_REQS;
 530                 }
 531
 532                 # check for negate
 533                 if (substr($_, 0, 1) eq "!") {
 534                         if (defined($neg) && $neg == 0) {
 535                                 # we have seen a positiv constraint as first one but this one is negative
 536                                 # this doesn't make sense
 537                                 print STDERR "Mixed positive and negative constraints for the same slot are not allowed.\n";
 538                                 return (undef, undef, undef, undef);
 539                         }
 540
 541                         if (!defined($neg)) {
 542                                 $has_limit = 1;
 543                                 push(@temp_obst, "  bs = bitset_set_all(bs);     /* allow all register (negative constraints given) */\n");
 544                         }
 545
 546                         $_   = substr($_, 1); # skip '!'
 547                         $neg = 1;
 548                 }
 549                 else {
 550                         if (defined($neg) && $neg == 1) {
 551                                 # we have seen a negative constraint as first one but this one is positive
 552                                 # this doesn't make sense
 553                                 print STDERR "Mixed positive and negative constraints for the same slot are not allowed.\n";
 554                                 return (undef, undef, undef, undef);
 555                         }
 556
 557                         if (!defined($neg)) {
 558                                 $has_limit = 1;
 559                                 push(@temp_obst, "  bs = bitset_clear_all(bs);   /* disallow all register (positive constraints given) */\n");
 560                         }
 561                         $neg = 0;
 562                 }
 563
 564                 # check if register belongs to one of the given classes
 565                 $temp = get_reg_class($_);
 566                 if (!defined($temp)) {
 567                         print STDERR "Unknown register '$_'!\n";
 568                         return (undef, undef, undef, undef);
 569                 }
 570
 571                 # set class
 572                 if (!defined($class)) {
 573                         $class = $temp;
 574                 }
 575                 elsif ($class ne $temp) {
 576                         # all registers must belong to the same class
 577                         print STDERR "Registerclass mismatch. '$_' is not member of class '$class'.\n";
 578                         return (undef, undef, undef, undef);
 579                 }
 580
 581                 if ($neg == 1) {
 582                         $has_limit = 1;
 583                         push(@temp_obst, "  bitset_clear(bs, ".get_reg_index($_).");         /* disallow $_ */\n");
 584                 }
 585                 else {
 586                         $has_limit = 1;
 587                         push(@temp_obst, "  bitset_set(bs, ".get_reg_index($_).");           /* allow $_ */\n");
 588                 }
 589         }
 590
 591         my @cur_class = @{ $reg_classes{"$class"} };
 592         for (my $idx = 0; $idx <= $#cur_class; $idx++) {
 593                 if (defined($cur_class[$idx]{"type"}) && ($cur_class[$idx]{"type"} & 4)) {
 594                         push(@temp_obst, "  bitset_clear(bs, ".get_reg_index($cur_class[$idx]{"name"}).");");
 595                         push(@temp_obst, "         /* disallow ignore reg ".$cur_class[$idx]{"name"}." */\n");
 596                 }
 597         }
 598
 599         if ($has_limit == 1) {
 600                 push(@obst_header_all, "void limit_reg_".$op."_".($in ? "in" : "out")."_".$idx."(void *_unused, bitset_t *bs);\n");
 601
 602                 push(@obst_limit_func, "/* limit the possible registers for ".($in ? "IN" : "OUT")." $idx at op $op */\n");
 603                 push(@obst_limit_func, "void limit_reg_".$op."_".($in ? "in" : "out")."_".$idx."(void *_unused, bitset_t *bs) {\n");
 604                 push(@obst_limit_func, @temp_obst);
 605                 push(@obst_limit_func, "}\n\n");
 606         }
 607
 608         return ($class, $has_limit, $same_pos, $different_pos);
 609 }