| 1 |
=head1 NAME |
| 2 |
|
| 3 |
Faster - do some things faster |
| 4 |
|
| 5 |
=head1 SYNOPSIS |
| 6 |
|
| 7 |
use Faster; |
| 8 |
|
| 9 |
perl -MFaster ... |
| 10 |
|
| 11 |
=head1 DESCRIPTION |
| 12 |
|
| 13 |
This module implements a very simple-minded JIT. It works by more or less |
| 14 |
translating every function it sees into a C program, compiling it and then |
| 15 |
replacing the function by the compiled code. |
| 16 |
|
| 17 |
As a result, startup times are immense, as every function might lead to a |
| 18 |
full-blown compilation. |
| 19 |
|
| 20 |
The speed improvements are also not great, you can expect 20% or so on |
| 21 |
average, for code that runs very often. |
| 22 |
|
| 23 |
Faster is in the early stages of development. Due to its design its |
| 24 |
relatively safe to use (it will either work or simply slowdown the program |
| 25 |
immensely, but rarely cause bugs). |
| 26 |
|
| 27 |
Usage is very easy, just C<use Faster> and every function called from then |
| 28 |
on will be compiled. |
| 29 |
|
| 30 |
Right now, Faster will leave ltos of F<*.c>, F<*.o> and F<*.so> files in |
| 31 |
F</tmp>, and it will even create those temporary files in an insecure |
| 32 |
manner, so watch out. |
| 33 |
|
| 34 |
=over 4 |
| 35 |
|
| 36 |
=cut |
| 37 |
|
| 38 |
package Faster; |
| 39 |
|
| 40 |
use strict; |
| 41 |
use Config; |
| 42 |
use B (); |
| 43 |
use Digest::MD5 (); |
| 44 |
use DynaLoader (); |
| 45 |
|
| 46 |
BEGIN { |
| 47 |
our $VERSION = '0.01'; |
| 48 |
|
| 49 |
require XSLoader; |
| 50 |
XSLoader::load __PACKAGE__, $VERSION; |
| 51 |
} |
| 52 |
|
| 53 |
my $COMPILE = "$Config{cc} -c -I$Config{archlibexp}/CORE $Config{optimize} $Config{ccflags} $Config{cccdlflags}"; |
| 54 |
my $LINK = "$Config{ld} $Config{ldflags} $Config{lddlflags} $Config{ccdlflags}"; |
| 55 |
my $LIBS = "$Config{libs}"; |
| 56 |
my $_o = $Config{_o}; |
| 57 |
my $_so = ".so"; |
| 58 |
|
| 59 |
# we don't need no steenking PIC on x86 |
| 60 |
$COMPILE =~ s/-f(?:PIC|pic)//g |
| 61 |
if $Config{archname} =~ /^(i[3456]86)-/; |
| 62 |
|
| 63 |
my $opt_assert = 1; |
| 64 |
|
| 65 |
our $source; |
| 66 |
|
| 67 |
our @ops; |
| 68 |
our $op; |
| 69 |
our $op_name; |
| 70 |
our @op_loop; |
| 71 |
our %op_regcomp; |
| 72 |
|
| 73 |
my %flag; |
| 74 |
|
| 75 |
# complex flag steting is no longer required, rewrite this ugly code |
| 76 |
for (split /\n/, <<EOF) { |
| 77 |
leavesub unsafe |
| 78 |
leavesublv unsafe |
| 79 |
return unsafe |
| 80 |
flip unsafe |
| 81 |
goto unsafe |
| 82 |
last unsafe |
| 83 |
redo unsafe |
| 84 |
next unsafe |
| 85 |
eval unsafe |
| 86 |
leaveeval unsafe |
| 87 |
entertry unsafe |
| 88 |
formline unsafe |
| 89 |
grepstart unsafe |
| 90 |
mapstart unsafe |
| 91 |
substcont unsafe |
| 92 |
entereval unsafe noasync todo |
| 93 |
require unsafe |
| 94 |
|
| 95 |
mapstart noasync |
| 96 |
grepstart noasync |
| 97 |
match noasync |
| 98 |
|
| 99 |
last noasync |
| 100 |
next noasync |
| 101 |
redo noasync |
| 102 |
seq noasync |
| 103 |
pushmark noasync extend=0 |
| 104 |
padsv noasync extend=1 |
| 105 |
padav noasync extend=1 |
| 106 |
padhv noasync extend=1 |
| 107 |
padany noasync extend=1 |
| 108 |
entersub noasync |
| 109 |
aassign noasync |
| 110 |
sassign noasync |
| 111 |
rv2av noasync |
| 112 |
rv2cv noasync |
| 113 |
rv2gv noasync |
| 114 |
rv2hv noasync |
| 115 |
refgen noasync |
| 116 |
nextstate noasync |
| 117 |
gv noasync |
| 118 |
gvsv noasync |
| 119 |
add noasync |
| 120 |
subtract noasync |
| 121 |
multiply noasync |
| 122 |
divide noasync |
| 123 |
complement noasync |
| 124 |
cond_expr noasync |
| 125 |
and noasync |
| 126 |
or noasync |
| 127 |
not noasync |
| 128 |
defined noasync |
| 129 |
method_named noasync |
| 130 |
preinc noasync |
| 131 |
postinc noasync |
| 132 |
predec noasync |
| 133 |
postdec noasync |
| 134 |
stub noasync |
| 135 |
unstack noasync |
| 136 |
leaveloop noasync |
| 137 |
aelem noasync |
| 138 |
aelemfast noasync |
| 139 |
helem noasync |
| 140 |
pushre noasync |
| 141 |
subst noasync |
| 142 |
const noasync extend=1 |
| 143 |
list noasync |
| 144 |
join noasync |
| 145 |
split noasync |
| 146 |
concat noasync |
| 147 |
push noasync |
| 148 |
pop noasync |
| 149 |
shift noasync |
| 150 |
unshift noasync |
| 151 |
length noasync |
| 152 |
substr noasync |
| 153 |
stringify noasync |
| 154 |
eq noasync |
| 155 |
ne noasync |
| 156 |
gt noasync |
| 157 |
lt noasync |
| 158 |
ge noasync |
| 159 |
le noasync |
| 160 |
enteriter noasync |
| 161 |
ord noasync |
| 162 |
orassign noasync |
| 163 |
regcomp noasync |
| 164 |
regcreset noasync |
| 165 |
regcmaybe noasync |
| 166 |
|
| 167 |
iter async |
| 168 |
EOF |
| 169 |
my (undef, $op, @flags) = split /\s+/; |
| 170 |
|
| 171 |
undef $flag{$_}{$op} |
| 172 |
for ("known", @flags); |
| 173 |
} |
| 174 |
|
| 175 |
my %callop = ( |
| 176 |
entersub => "(PL_ppaddr [OP_ENTERSUB]) (aTHX)", |
| 177 |
mapstart => "Perl_pp_grepstart (aTHX)", |
| 178 |
); |
| 179 |
|
| 180 |
sub callop { |
| 181 |
$callop{$op_name} || "Perl_pp_$op_name (aTHX)" |
| 182 |
} |
| 183 |
|
| 184 |
sub assert { |
| 185 |
return unless $opt_assert; |
| 186 |
$source .= " assert ((\"$op_name\", ($_[0])));\n"; |
| 187 |
} |
| 188 |
|
| 189 |
sub out_callop { |
| 190 |
assert "nextop == (OP *)$$op"; |
| 191 |
$source .= " PL_op = nextop; nextop = " . (callop $op) . ";\n"; |
| 192 |
} |
| 193 |
|
| 194 |
sub out_cond_jump { |
| 195 |
$source .= " if (nextop == (OP *)${$_[0]}L) goto op_${$_[0]};\n"; |
| 196 |
} |
| 197 |
|
| 198 |
sub out_jump_next { |
| 199 |
out_cond_jump $op_regcomp{$$op} |
| 200 |
if $op_regcomp{$$op}; |
| 201 |
|
| 202 |
assert "nextop == (OP *)${$op->next}"; |
| 203 |
$source .= " goto op_${$op->next};\n"; |
| 204 |
} |
| 205 |
|
| 206 |
sub out_next { |
| 207 |
$source .= " nextop = (OP *)${$op->next}L;\n"; |
| 208 |
|
| 209 |
out_jump_next; |
| 210 |
} |
| 211 |
|
| 212 |
sub out_linear { |
| 213 |
out_callop; |
| 214 |
out_jump_next; |
| 215 |
} |
| 216 |
|
| 217 |
sub op_entersub { |
| 218 |
out_callop; |
| 219 |
$source .= " RUNOPS_TILL ((OP *)${$op->next}L);\n"; |
| 220 |
out_jump_next; |
| 221 |
} |
| 222 |
|
| 223 |
*op_require = \&op_entersub; |
| 224 |
|
| 225 |
sub op_nextstate { |
| 226 |
$source .= " PL_curcop = (COP *)nextop;\n"; |
| 227 |
$source .= " PL_stack_sp = PL_stack_base + cxstack[cxstack_ix].blk_oldsp;\n"; |
| 228 |
$source .= " FREETMPS;\n"; |
| 229 |
|
| 230 |
out_next; |
| 231 |
} |
| 232 |
|
| 233 |
sub op_pushmark { |
| 234 |
$source .= " PUSHMARK (PL_stack_sp);\n"; |
| 235 |
|
| 236 |
out_next; |
| 237 |
} |
| 238 |
|
| 239 |
if ($Config{useithreads} ne "define") { |
| 240 |
# disable optimisations on ithreads |
| 241 |
|
| 242 |
*op_const = sub { |
| 243 |
$source .= " { dSP; XPUSHs ((SV *)${$op->sv}L); PUTBACK; }\n"; |
| 244 |
|
| 245 |
out_next; |
| 246 |
}; |
| 247 |
|
| 248 |
*op_gv = \&op_const; |
| 249 |
|
| 250 |
*op_aelemfast = sub { |
| 251 |
my $targ = $op->targ; |
| 252 |
my $private = $op->private; |
| 253 |
|
| 254 |
$source .= " {\n"; |
| 255 |
|
| 256 |
if ($op->flags & B::OPf_SPECIAL) { |
| 257 |
$source .= " AV *av = (AV*)PAD_SV((PADOFFSET)$targ);\n"; |
| 258 |
} else { |
| 259 |
$source .= " AV *av = GvAV ((GV *)${$op->sv}L);\n"; |
| 260 |
} |
| 261 |
|
| 262 |
if ($op->flags & B::OPf_MOD) { |
| 263 |
$source .= " SV *sv = *av_fetch (av, $private, 1);\n"; |
| 264 |
} else { |
| 265 |
$source .= " SV **svp = av_fetch (av, $private, 0); SV *sv = svp ? *svp : &PL_sv_undef;\n"; |
| 266 |
} |
| 267 |
|
| 268 |
if (!($op->flags & B::OPf_MOD)) { |
| 269 |
$source .= " if (SvGMAGICAL (sv)) sv = sv_mortalcopy (sv);\n"; |
| 270 |
} |
| 271 |
|
| 272 |
$source .= " dSP;\n"; |
| 273 |
$source .= " XPUSHs (sv);\n"; |
| 274 |
$source .= " PUTBACK;\n"; |
| 275 |
$source .= " }\n"; |
| 276 |
|
| 277 |
out_next; |
| 278 |
}; |
| 279 |
|
| 280 |
*op_gvsv = sub { |
| 281 |
$source .= " {\n"; |
| 282 |
$source .= " dSP;\n"; |
| 283 |
$source .= " EXTEND (SP, 1);\n"; |
| 284 |
|
| 285 |
if ($op->private & B::OPpLVAL_INTRO) { |
| 286 |
$source .= " PUSHs (save_scalar ((GV *)${$op->sv}L));\n"; |
| 287 |
} else { |
| 288 |
$source .= " PUSHs (GvSV ((GV *)${$op->sv}L));\n"; |
| 289 |
} |
| 290 |
|
| 291 |
$source .= " PUTBACK;\n"; |
| 292 |
$source .= " }\n"; |
| 293 |
|
| 294 |
out_next; |
| 295 |
}; |
| 296 |
} |
| 297 |
|
| 298 |
# does kill Crossfire/res2pm |
| 299 |
sub op_stringify { |
| 300 |
my $targ = $op->targ; |
| 301 |
|
| 302 |
$source .= <<EOF; |
| 303 |
{ |
| 304 |
dSP; |
| 305 |
SV *targ = PAD_SV ((PADOFFSET)$targ); |
| 306 |
sv_copypv (TARG, TOPs); |
| 307 |
SETTARG; |
| 308 |
PUTBACK; |
| 309 |
} |
| 310 |
EOF |
| 311 |
|
| 312 |
out_next; |
| 313 |
} |
| 314 |
|
| 315 |
sub op_and { |
| 316 |
$source .= <<EOF; |
| 317 |
{ |
| 318 |
dSP; |
| 319 |
|
| 320 |
if (SvTRUE (TOPs)) |
| 321 |
{ |
| 322 |
--SP; |
| 323 |
PUTBACK; |
| 324 |
nextop = (OP *)${$op->other}L; |
| 325 |
goto op_${$op->other}; |
| 326 |
} |
| 327 |
} |
| 328 |
EOF |
| 329 |
|
| 330 |
out_next; |
| 331 |
} |
| 332 |
|
| 333 |
sub op_or { |
| 334 |
$source .= <<EOF; |
| 335 |
{ |
| 336 |
dSP; |
| 337 |
|
| 338 |
if (!SvTRUE (TOPs)) |
| 339 |
{ |
| 340 |
--SP; |
| 341 |
PUTBACK; |
| 342 |
nextop = (OP *)${$op->other}L; |
| 343 |
goto op_${$op->other}; |
| 344 |
} |
| 345 |
} |
| 346 |
EOF |
| 347 |
|
| 348 |
out_next; |
| 349 |
} |
| 350 |
|
| 351 |
sub op_padsv { |
| 352 |
my $flags = $op->flags; |
| 353 |
my $target = $op->targ; |
| 354 |
|
| 355 |
$source .= <<EOF; |
| 356 |
{ |
| 357 |
dSP; |
| 358 |
XPUSHs (PAD_SV ((PADOFFSET)$target)); |
| 359 |
PUTBACK; |
| 360 |
EOF |
| 361 |
if ($op->flags & B::OPf_MOD) { |
| 362 |
if ($op->private & B::OPpLVAL_INTRO) { |
| 363 |
$source .= " SAVECLEARSV (PAD_SVl ((PADOFFSET)$target));\n"; |
| 364 |
} elsif ($op->private & B::OPpDEREF) { |
| 365 |
my $deref = $op->private & B::OPpDEREF; |
| 366 |
$source .= " Perl_vivify_ref (PAD_SVl ((PADOFFSET)$target), $deref);\n"; |
| 367 |
} |
| 368 |
} |
| 369 |
$source .= <<EOF; |
| 370 |
} |
| 371 |
EOF |
| 372 |
|
| 373 |
out_next; |
| 374 |
} |
| 375 |
|
| 376 |
# pattern const+ (or general push1) |
| 377 |
# pattern pushmark return(?) |
| 378 |
# pattern pushmark gv rv2av pushmark padsv+o.ä. aassign |
| 379 |
|
| 380 |
# pattern const method_named |
| 381 |
sub op_method_named { |
| 382 |
$source .= <<EOF; |
| 383 |
{ |
| 384 |
static HV *last_stash; |
| 385 |
static SV *last_cv; |
| 386 |
static U32 last_sub_generation; |
| 387 |
|
| 388 |
SV *obj = *(PL_stack_base + TOPMARK + 1); |
| 389 |
|
| 390 |
if (!SvGMAGICAL (obj) && SvROK (obj) && SvOBJECT (SvRV (obj))) |
| 391 |
{ |
| 392 |
dSP; |
| 393 |
HV *stash = SvSTASH (SvRV (obj)); |
| 394 |
|
| 395 |
/* simple "polymorphic" inline cache */ |
| 396 |
if (stash == last_stash |
| 397 |
&& PL_sub_generation == last_sub_generation) |
| 398 |
{ |
| 399 |
XPUSHs (last_cv); |
| 400 |
PUTBACK; |
| 401 |
} |
| 402 |
else |
| 403 |
{ |
| 404 |
PL_op = nextop; nextop = Perl_pp_method_named (aTHX); |
| 405 |
|
| 406 |
SPAGAIN; |
| 407 |
last_sub_generation = PL_sub_generation; |
| 408 |
last_stash = stash; |
| 409 |
last_cv = TOPs; |
| 410 |
} |
| 411 |
} |
| 412 |
else |
| 413 |
{ |
| 414 |
/* error case usually */ |
| 415 |
PL_op = nextop; nextop = Perl_pp_method_named (aTHX); |
| 416 |
} |
| 417 |
} |
| 418 |
EOF |
| 419 |
|
| 420 |
out_next; |
| 421 |
} |
| 422 |
|
| 423 |
sub op_grepstart { |
| 424 |
out_callop; |
| 425 |
$op = $op->next; |
| 426 |
out_cond_jump $op->other; |
| 427 |
out_jump_next; |
| 428 |
} |
| 429 |
|
| 430 |
*op_mapstart = \&op_grepstart; |
| 431 |
|
| 432 |
sub op_substcont { |
| 433 |
out_callop; |
| 434 |
out_cond_jump $op->other->pmreplstart; |
| 435 |
assert "nextop == (OP *)${$op->other->next}L"; |
| 436 |
$source .= " goto op_${$op->other->next};\n"; |
| 437 |
} |
| 438 |
|
| 439 |
sub out_break_op { |
| 440 |
my ($idx) = @_; |
| 441 |
|
| 442 |
out_callop; |
| 443 |
|
| 444 |
out_cond_jump $_->[$idx] |
| 445 |
for reverse @op_loop; |
| 446 |
|
| 447 |
$source .= " return nextop;\n"; |
| 448 |
} |
| 449 |
|
| 450 |
sub xop_next { |
| 451 |
out_break_op 0; |
| 452 |
} |
| 453 |
|
| 454 |
sub op_last { |
| 455 |
out_break_op 1; |
| 456 |
} |
| 457 |
|
| 458 |
sub xop_redo { |
| 459 |
out_break_op 2; |
| 460 |
} |
| 461 |
|
| 462 |
sub cv2c { |
| 463 |
my ($cv) = @_; |
| 464 |
|
| 465 |
local @ops; |
| 466 |
local @op_loop; |
| 467 |
local %op_regcomp; |
| 468 |
|
| 469 |
my %opsseen; |
| 470 |
my @todo = $cv->START; |
| 471 |
|
| 472 |
while (my $op = shift @todo) { |
| 473 |
for (; $$op; $op = $op->next) { |
| 474 |
last if $opsseen{$$op}++; |
| 475 |
push @ops, $op; |
| 476 |
|
| 477 |
my $name = $op->name; |
| 478 |
my $class = B::class $op; |
| 479 |
|
| 480 |
if ($class eq "LOGOP") { |
| 481 |
unshift @todo, $op->other; # unshift vs. push saves jumps |
| 482 |
|
| 483 |
# regcomp/o patches ops at runtime, lets expect that |
| 484 |
$op_regcomp{${$op->first}} = $op->next |
| 485 |
if $name eq "regcomp" && $op->other->pmflags & B::PMf_KEEP; |
| 486 |
|
| 487 |
} elsif ($class eq "PMOP") { |
| 488 |
unshift @todo, $op->pmreplstart if ${$op->pmreplstart}; |
| 489 |
|
| 490 |
} elsif ($class eq "LOOP") { |
| 491 |
push @op_loop, [$op->nextop, $op->lastop->next, $op->redoop->next]; |
| 492 |
push @todo, $op->nextop, $op->lastop->next, $op->redoop->next; |
| 493 |
} |
| 494 |
} |
| 495 |
} |
| 496 |
|
| 497 |
local $source = <<EOF; |
| 498 |
OP *%%%FUNC%%% (pTHX) |
| 499 |
{ |
| 500 |
register OP *nextop = (OP *)${$ops[0]}L; |
| 501 |
EOF |
| 502 |
|
| 503 |
while (@ops) { |
| 504 |
$op = shift @ops; |
| 505 |
$op_name = $op->name; |
| 506 |
|
| 507 |
$source .= "op_$$op: /* $op_name */\n"; |
| 508 |
#$source .= "fprintf (stderr, \"$$op in op $op_name\\n\");\n";#d# |
| 509 |
#$source .= "{ dSP; sv_dump (TOPs); }\n";#d# |
| 510 |
|
| 511 |
$source .= " PERL_ASYNC_CHECK ();\n" |
| 512 |
unless exists $flag{noasync}{$op_name}; |
| 513 |
|
| 514 |
if (my $can = __PACKAGE__->can ("op_$op_name")) { |
| 515 |
# handcrafted replacement |
| 516 |
$can->($op); |
| 517 |
|
| 518 |
} elsif (exists $flag{unsafe}{$op_name}) { |
| 519 |
# unsafe, return to interpreter |
| 520 |
assert "nextop == (OP *)$$op"; |
| 521 |
$source .= " return nextop;\n"; |
| 522 |
|
| 523 |
} elsif ("LOGOP" eq B::class $op) { |
| 524 |
# logical operation with optionaö branch |
| 525 |
out_callop; |
| 526 |
out_cond_jump $op->other; |
| 527 |
out_jump_next; |
| 528 |
|
| 529 |
} elsif ("PMOP" eq B::class $op) { |
| 530 |
# regex-thingy |
| 531 |
out_callop; |
| 532 |
out_cond_jump $op->pmreplroot if ${$op->pmreplroot}; |
| 533 |
out_jump_next; |
| 534 |
|
| 535 |
} else { |
| 536 |
# normal operator, linear execution |
| 537 |
out_linear; |
| 538 |
} |
| 539 |
} |
| 540 |
|
| 541 |
$op_name = "func exit"; assert (0); |
| 542 |
|
| 543 |
$source .= <<EOF; |
| 544 |
op_0: |
| 545 |
return 0; |
| 546 |
} |
| 547 |
EOF |
| 548 |
#warn $source; |
| 549 |
|
| 550 |
$source |
| 551 |
} |
| 552 |
|
| 553 |
sub source2ptr { |
| 554 |
my ($source) = @_; |
| 555 |
|
| 556 |
my $md5 = Digest::MD5::md5_hex $source; |
| 557 |
$source =~ s/%%%FUNC%%%/Faster_$md5/; |
| 558 |
|
| 559 |
my $stem = "/tmp/$md5"; |
| 560 |
|
| 561 |
unless (-e "$stem$_so") { |
| 562 |
open FILE, ">:raw", "$stem.c"; |
| 563 |
print FILE <<EOF; |
| 564 |
#define PERL_NO_GET_CONTEXT |
| 565 |
|
| 566 |
#include <assert.h> |
| 567 |
|
| 568 |
#include "EXTERN.h" |
| 569 |
#include "perl.h" |
| 570 |
#include "XSUB.h" |
| 571 |
|
| 572 |
#define RUNOPS_TILL(op) \\ |
| 573 |
while (nextop != (op)) \\ |
| 574 |
{ \\ |
| 575 |
PERL_ASYNC_CHECK (); \\ |
| 576 |
PL_op = nextop; nextop = (PL_op->op_ppaddr)(aTHX); \\ |
| 577 |
} |
| 578 |
|
| 579 |
EOF |
| 580 |
print FILE $source; |
| 581 |
close FILE; |
| 582 |
system "$COMPILE -o $stem$_o $stem.c"; |
| 583 |
system "$LINK -o $stem$_so $stem$_o $LIBS"; |
| 584 |
} |
| 585 |
|
| 586 |
# warn $source; |
| 587 |
my $so = DynaLoader::dl_load_file "$stem$_so" |
| 588 |
or die "$stem$_so: $!"; |
| 589 |
|
| 590 |
DynaLoader::dl_find_symbol $so, "Faster_$md5" |
| 591 |
or die "Faster_$md5: $!" |
| 592 |
} |
| 593 |
|
| 594 |
sub entersub { |
| 595 |
my ($cv) = @_; |
| 596 |
|
| 597 |
# always compile the whole stash |
| 598 |
# my @stash = $cv->STASH->ARRAY; |
| 599 |
# warn join ":", @stash; |
| 600 |
# exit; |
| 601 |
|
| 602 |
eval { |
| 603 |
my $source = cv2c $cv; |
| 604 |
|
| 605 |
my $ptr = source2ptr $source; |
| 606 |
|
| 607 |
patch_cv $cv, $ptr; |
| 608 |
}; |
| 609 |
|
| 610 |
warn $@ if $@; |
| 611 |
} |
| 612 |
|
| 613 |
hook_entersub; |
| 614 |
|
| 615 |
1; |
| 616 |
|
| 617 |
=back |
| 618 |
|
| 619 |
=head1 BUGS/LIMITATIONS |
| 620 |
|
| 621 |
Perl will check much less often for asynchronous signals in |
| 622 |
Faster-compiled code. It tries to check on every function call, loop |
| 623 |
iteration and every I/O operator, though. |
| 624 |
|
| 625 |
The following things will disable Faster. If you manage to enable them at |
| 626 |
runtime, bad things will happen. |
| 627 |
|
| 628 |
enabled tainting |
| 629 |
enabled debugging |
| 630 |
|
| 631 |
This will dramatically reduce Faster's performance: |
| 632 |
|
| 633 |
threads (but you don't care about speed if you use threads anyway) |
| 634 |
|
| 635 |
These constructs will force the use of the interpreter as soon as they are |
| 636 |
being executed, for the rest of the currently executed: |
| 637 |
|
| 638 |
.., ... (flipflop operators) |
| 639 |
goto |
| 640 |
next, redo (but not well-behaved last's) |
| 641 |
eval |
| 642 |
require |
| 643 |
any use of formats |
| 644 |
|
| 645 |
=head1 AUTHOR |
| 646 |
|
| 647 |
Marc Lehmann <schmorp@schmorp.de> |
| 648 |
http://home.schmorp.de/ |
| 649 |
|
| 650 |
=cut |
| 651 |
|
