3 # Copyright (c) 1996, 1997, 1998 Malcolm Beattie
5 # You may distribute under the terms of either the GNU General Public
6 # License or the Artistic License, as specified in the README file.
10 use B qw(main_start main_root class comppadlist peekop svref_2object
11 timing_info init_av sv_undef amagic_generation
12 OPf_WANT_LIST OPf_WANT OPf_MOD OPf_STACKED OPf_SPECIAL
13 OPpASSIGN_BACKWARDS OPpLVAL_INTRO OPpDEREF_AV OPpDEREF_HV
14 OPpDEREF OPpFLIP_LINENUM G_ARRAY G_SCALAR
15 CXt_NULL CXt_SUB CXt_EVAL CXt_LOOP CXt_SUBST CXt_BLOCK
17 use B::C qw(save_unused_subs objsym init_sections mark_unused
18 output_all output_boilerplate output_main);
19 use B::Bblock qw(find_leaders);
20 use B::Stackobj qw(:types :flags);
22 # These should probably be elsewhere
23 # Flags for $op->flags
25 my $module; # module name (when compiled with -m)
26 my %done; # hash keyed by $$op of leaders of basic blocks
27 # which have already been done.
28 my $leaders; # ref to hash of basic block leaders. Keys are $$op
29 # addresses, values are the $op objects themselves.
30 my @bblock_todo; # list of leaders of basic blocks that need visiting
32 my @cc_todo; # list of tuples defining what PP code needs to be
33 # saved (e.g. CV, main or PMOP repl code). Each tuple
34 # is [$name, $root, $start, @padlist]. PMOP repl code
35 # tuples inherit padlist.
36 my @stack; # shadows perl's stack when contents are known.
37 # Values are objects derived from class B::Stackobj
38 my @pad; # Lexicals in current pad as Stackobj-derived objects
39 my @padlist; # Copy of current padlist so PMOP repl code can find it
40 my @cxstack; # Shadows the (compile-time) cxstack for next,last,redo
41 my $jmpbuf_ix = 0; # Next free index for dynamically allocated jmpbufs
42 my %constobj; # OP_CONST constants as Stackobj-derived objects
44 my $need_freetmps = 0; # We may postpone FREETMPS to the end of each basic
45 # block or even to the end of each loop of blocks,
46 # depending on optimisation options.
47 my $know_op = 0; # Set when C variable op already holds the right op
48 # (from an immediately preceding DOOP(ppname)).
49 my $errors = 0; # Number of errors encountered
50 my %skip_stack; # Hash of PP names which don't need write_back_stack
51 my %skip_lexicals; # Hash of PP names which don't need write_back_lexicals
52 my %skip_invalidate; # Hash of PP names which don't need invalidate_lexicals
53 my %ignore_op; # Hash of ops which do nothing except returning op_next
54 my %need_curcop; # Hash of ops which need PL_curcop
57 foreach (qw(pp_scalar pp_regcmaybe pp_lineseq pp_scope pp_null)) {
63 my ($debug_op, $debug_stack, $debug_cxstack, $debug_pad, $debug_runtime,
64 $debug_shadow, $debug_queue, $debug_lineno, $debug_timings);
66 # Optimisation options. On the command line, use hyphens instead of
67 # underscores for compatibility with gcc-style options. We use
68 # underscores here because they are OK in (strict) barewords.
69 my ($freetmps_each_bblock, $freetmps_each_loop, $omit_taint);
70 my %optimise = (freetmps_each_bblock => \$freetmps_each_bblock,
71 freetmps_each_loop => \$freetmps_each_loop,
72 omit_taint => \$omit_taint);
73 # perl patchlevel to generate code for (defaults to current patchlevel)
74 my $patchlevel = int(0.5 + 1000 * ($] - 5));
76 # Could rewrite push_runtime() and output_runtime() to use a
77 # temporary file if memory is at a premium.
78 my $ppname; # name of current fake PP function
80 my $declare_ref; # Hash ref keyed by C variable type of declarations.
82 my @pp_list; # list of [$ppname, $runtime_list_ref, $declare_ref]
83 # tuples to be written out.
87 sub init_hash { map { $_ => 1 } @_ }
90 # Initialise the hashes for the default PP functions where we can avoid
91 # either write_back_stack, write_back_lexicals or invalidate_lexicals.
93 %skip_lexicals = init_hash qw(pp_enter pp_enterloop);
94 %skip_invalidate = init_hash qw(pp_enter pp_enterloop);
95 %need_curcop = init_hash qw(pp_rv2gv pp_bless pp_repeat pp_sort pp_caller
96 pp_reset pp_rv2cv pp_entereval pp_require pp_dofile
97 pp_entertry pp_enterloop pp_enteriter pp_entersub
101 if ($debug_runtime) {
104 runtime(map { chomp; "/* $_ */"} @_);
109 my ($type, $var) = @_;
110 push(@{$declare_ref->{$type}}, $var);
114 push(@$runtime_list_ref, @_);
115 warn join("\n", @_) . "\n" if $debug_runtime;
119 push(@pp_list, [$ppname, $runtime_list_ref, $declare_ref]);
124 print qq(#include "cc_runtime.h"\n);
125 foreach $ppdata (@pp_list) {
126 my ($name, $runtime, $declare) = @$ppdata;
127 print "\nstatic\nPP($name)\n{\n";
128 my ($type, $varlist, $line);
129 while (($type, $varlist) = each %$declare) {
130 print "\t$type ", join(", ", @$varlist), ";\n";
132 foreach $line (@$runtime) {
142 push_runtime("\t$line");
148 $runtime_list_ref = [];
151 declare("I32", "oldsave");
152 declare("SV", "**svp");
153 map { declare("SV", "*$_") } qw(sv src dst left right);
154 declare("MAGIC", "*mg");
155 $decl->add("static OP * $ppname (pTHX);");
156 debug "init_pp: $ppname\n" if $debug_queue;
159 # Initialise runtime_callback function for Stackobj class
160 BEGIN { B::Stackobj::set_callback(\&runtime) }
162 # Initialise saveoptree_callback for B::C class
164 my ($name, $root, $start, @pl) = @_;
165 debug "cc_queue: name $name, root $root, start $start, padlist (@pl)\n"
167 if ($name eq "*ignore*") {
170 push(@cc_todo, [$name, $root, $start, (@pl ? @pl : @padlist)]);
172 my $fakeop = new B::FAKEOP ("next" => 0, sibling => 0, ppaddr => $name);
173 $start = $fakeop->save;
174 debug "cc_queue: name $name returns $start\n" if $debug_queue;
177 BEGIN { B::C::set_callback(\&cc_queue) }
179 sub valid_int { $_[0]->{flags} & VALID_INT }
180 sub valid_double { $_[0]->{flags} & VALID_DOUBLE }
181 sub valid_numeric { $_[0]->{flags} & (VALID_INT | VALID_DOUBLE) }
182 sub valid_sv { $_[0]->{flags} & VALID_SV }
184 sub top_int { @stack ? $stack[-1]->as_int : "TOPi" }
185 sub top_double { @stack ? $stack[-1]->as_double : "TOPn" }
186 sub top_numeric { @stack ? $stack[-1]->as_numeric : "TOPn" }
187 sub top_sv { @stack ? $stack[-1]->as_sv : "TOPs" }
188 sub top_bool { @stack ? $stack[-1]->as_bool : "SvTRUE(TOPs)" }
190 sub pop_int { @stack ? (pop @stack)->as_int : "POPi" }
191 sub pop_double { @stack ? (pop @stack)->as_double : "POPn" }
192 sub pop_numeric { @stack ? (pop @stack)->as_numeric : "POPn" }
193 sub pop_sv { @stack ? (pop @stack)->as_sv : "POPs" }
196 return ((pop @stack)->as_bool);
198 # Careful: POPs has an auto-decrement and SvTRUE evaluates
199 # its argument more than once.
200 runtime("sv = POPs;");
205 sub write_back_lexicals {
206 my $avoid = shift || 0;
207 debug "write_back_lexicals($avoid) called from @{[(caller(1))[3]]}\n"
210 foreach $lex (@pad) {
211 next unless ref($lex);
212 $lex->write_back unless $lex->{flags} & $avoid;
216 sub write_back_stack {
218 return unless @stack;
219 runtime(sprintf("EXTEND(sp, %d);", scalar(@stack)));
220 foreach $obj (@stack) {
221 runtime(sprintf("PUSHs((SV*)%s);", $obj->as_sv));
226 sub invalidate_lexicals {
227 my $avoid = shift || 0;
228 debug "invalidate_lexicals($avoid) called from @{[(caller(1))[3]]}\n"
231 foreach $lex (@pad) {
232 next unless ref($lex);
233 $lex->invalidate unless $lex->{flags} & $avoid;
237 sub reload_lexicals {
239 foreach $lex (@pad) {
240 next unless ref($lex);
241 my $type = $lex->{type};
242 if ($type == T_INT) {
244 } elsif ($type == T_DOUBLE) {
253 package B::Pseudoreg;
255 # This class allocates pseudo-registers (OK, so they're C variables).
257 my %alloc; # Keyed by variable name. A value of 1 means the
258 # variable has been declared. A value of 2 means
261 sub new_scope { %alloc = () }
264 my ($class, $type, $prefix) = @_;
265 my ($ptr, $i, $varname, $status, $obj);
266 $prefix =~ s/^(\**)//;
270 $varname = "$prefix$i";
271 $status = $alloc{$varname};
272 } while $status == 2;
275 B::CC::declare($type, "$ptr$varname");
276 $alloc{$varname} = 2; # declared and in use
278 $obj = bless \$varname, $class;
283 $alloc{$$obj} = 1; # no longer in use but still declared
289 # This class gives a standard API for a perl object to shadow a
290 # C variable and only generate reloads/write-backs when necessary.
292 # Use $obj->load($foo) instead of runtime("shadowed_c_var = foo").
293 # Use $obj->write_back whenever shadowed_c_var needs to be up to date.
294 # Use $obj->invalidate whenever an unknown function may have
298 my ($class, $write_back) = @_;
299 # Object fields are perl shadow variable, validity flag
300 # (for *C* variable) and callback sub for write_back
301 # (passed perl shadow variable as argument).
302 bless [undef, 1, $write_back], $class;
305 my ($obj, $newval) = @_;
306 $obj->[1] = 0; # C variable no longer valid
312 $obj->[1] = 1; # C variable will now be valid
313 &{$obj->[2]}($obj->[0]);
316 sub invalidate { $_[0]->[1] = 0 } # force C variable to be invalid
318 my $curcop = new B::Shadow (sub {
319 my $opsym = shift->save;
320 runtime("PL_curcop = (COP*)$opsym;");
324 # Context stack shadowing. Mimics stuff in pp_ctl.c, cop.h and so on.
327 my $cxix = $#cxstack;
328 while ($cxix >= 0 && $cxstack[$cxix]->{type} != CXt_LOOP) {
331 debug "dopoptoloop: returning $cxix" if $debug_cxstack;
337 my $cxix = $#cxstack;
339 ($cxstack[$cxix]->{type} != CXt_LOOP ||
340 $cxstack[$cxix]->{label} ne $label)) {
343 debug "dopoptolabel: returning $cxix" if $debug_cxstack;
349 my $file = $curcop->[0]->filegv->SV->PV;
350 my $line = $curcop->[0]->line;
353 warn sprintf("%s:%d: $format\n", $file, $line, @_);
355 warn sprintf("%s:%d: %s\n", $file, $line, $format);
360 # Load pad takes (the elements of) a PADLIST as arguments and loads
361 # up @pad with Stackobj-derived objects which represent those lexicals.
362 # If/when perl itself can generate type information (my int $foo) then
363 # we'll take advantage of that here. Until then, we'll use various hacks
364 # to tell the compiler when we want a lexical to be a particular type
365 # or to be a register.
368 my ($namelistav, $valuelistav) = @_;
370 my @namelist = $namelistav->ARRAY;
371 my @valuelist = $valuelistav->ARRAY;
374 debug "load_pad: $#namelist names, $#valuelist values\n" if $debug_pad;
375 # Temporary lexicals don't get named so it's possible for @valuelist
376 # to be strictly longer than @namelist. We count $ix up to the end of
377 # @valuelist but index into @namelist for the name. Any temporaries which
378 # run off the end of @namelist will make $namesv undefined and we treat
379 # that the same as having an explicit SPECIAL sv_undef object in @namelist.
380 # [XXX If/when @_ becomes a lexical, we must start at 0 here.]
381 for ($ix = 1; $ix < @valuelist; $ix++) {
382 my $namesv = $namelist[$ix];
383 my $type = T_UNKNOWN;
386 my $class = class($namesv);
387 if (!defined($namesv) || $class eq "SPECIAL") {
388 # temporaries have &PL_sv_undef instead of a PVNV for a name
389 $flags = VALID_SV|TEMPORARY|REGISTER;
391 if ($namesv->PV =~ /^\$(.*)_([di])(r?)$/) {
395 $flags = VALID_SV|VALID_INT;
396 } elsif ($2 eq "d") {
398 $flags = VALID_SV|VALID_DOUBLE;
400 $flags |= REGISTER if $3;
403 $pad[$ix] = new B::Stackobj::Padsv ($type, $flags, $ix,
404 "i_$name", "d_$name");
406 debug sprintf("PL_curpad[$ix] = %s\n", $pad[$ix]->peek) if $debug_pad;
412 for ($ix = 1; $ix <= $#pad; $ix++) {
413 my $type = $pad[$ix]->{type};
414 declare("IV", $type == T_INT ?
415 sprintf("%s=0",$pad[$ix]->{iv}):$pad[$ix]->{iv}) if $pad[$ix]->save_int;
416 declare("double", $type == T_DOUBLE ?
417 sprintf("%s = 0",$pad[$ix]->{nv}):$pad[$ix]->{nv} )if $pad[$ix]->save_double;
424 sub peek_stack { sprintf "stack = %s\n", join(" ", map($_->minipeek, @stack)) }
432 # XXX Preserve original label name for "real" labels?
433 return sprintf("lab_%x", $$op);
438 push_runtime(sprintf(" %s:", label($op)));
443 my $opsym = $op->save;
444 runtime("PL_op = $opsym;") unless $know_op;
450 my $ppname = $op->ppaddr;
451 my $sym = loadop($op);
452 runtime("DOOP($ppname);");
459 my $flags = $op->flags;
460 return (($flags & OPf_WANT) ? (($flags & OPf_WANT)== OPf_WANT_LIST? G_ARRAY:G_SCALAR) : "dowantarray()");
464 # Code generation for PP code
474 my $gimme = gimme($op);
475 if ($gimme != G_ARRAY) {
476 my $obj= new B::Stackobj::Const(sv_undef);
478 # XXX Change to push a constant sv_undef Stackobj onto @stack
480 #runtime("if ($gimme != G_ARRAY) XPUSHs(&PL_sv_undef);");
488 runtime("PP_UNSTACK;");
494 my $next = $op->next;
496 unshift(@bblock_todo, $next);
498 my $bool = pop_bool();
500 runtime(sprintf("if (!$bool) {XPUSHs(&PL_sv_no); goto %s;}", label($next)));
502 runtime(sprintf("if (!%s) goto %s;", top_bool(), label($next)),
510 my $next = $op->next;
512 unshift(@bblock_todo, $next);
514 my $bool = pop_bool @stack;
516 runtime(sprintf("if (%s) { XPUSHs(&PL_sv_yes); goto %s; }",
517 $bool, label($next)));
519 runtime(sprintf("if (%s) goto %s;", top_bool(), label($next)),
527 my $false = $op->false;
528 unshift(@bblock_todo, $false);
530 my $bool = pop_bool();
532 runtime(sprintf("if (!$bool) goto %s;", label($false)));
539 push(@stack, $pad[$ix]);
540 if ($op->flags & OPf_MOD) {
541 my $private = $op->private;
542 if ($private & OPpLVAL_INTRO) {
543 runtime("SAVECLEARSV(PL_curpad[$ix]);");
544 } elsif ($private & OPpDEREF) {
545 runtime(sprintf("vivify_ref(PL_curpad[%d], %d);",
546 $ix, $private & OPpDEREF));
547 $pad[$ix]->invalidate;
556 my $obj = $constobj{$$sv};
557 if (!defined($obj)) {
558 $obj = $constobj{$$sv} = new B::Stackobj::Const ($sv);
568 debug(sprintf("%s:%d\n", $op->filegv->SV->PV, $op->line)) if $debug_lineno;
569 runtime("TAINT_NOT;") unless $omit_taint;
570 runtime("sp = PL_stack_base + cxstack[cxstack_ix].blk_oldsp;");
571 if ($freetmps_each_bblock || $freetmps_each_loop) {
574 runtime("FREETMPS;");
581 $curcop->invalidate; # XXX?
582 return default_pp($op);
585 #default_pp will handle this:
586 #sub pp_bless { $curcop->write_back; default_pp(@_) }
587 #sub pp_repeat { $curcop->write_back; default_pp(@_) }
588 # The following subs need $curcop->write_back if we decide to support arybase:
589 # pp_pos, pp_substr, pp_index, pp_rindex, pp_aslice, pp_lslice, pp_splice
590 #sub pp_caller { $curcop->write_back; default_pp(@_) }
591 #sub pp_reset { $curcop->write_back; default_pp(@_) }
596 write_back_lexicals() unless $skip_lexicals{$ppname};
597 write_back_stack() unless $skip_stack{$ppname};
599 if ($op->private & OPpDEREF) {
600 $init->add(sprintf("((UNOP *)$sym)->op_first = $sym;"));
601 $init->add(sprintf("((UNOP *)$sym)->op_type = %d;",
608 my $ppname = $op->ppaddr;
609 if ( $op->flags & OPf_SPECIAL && $op->flags & OPf_STACKED){
610 #this indicates the sort BLOCK Array case
611 #ugly surgery required.
612 my $root=$op->first->sibling->first;
613 my $start=$root->first;
615 $op->first->sibling->save;
617 my $sym=$start->save;
618 my $fakeop=cc_queue("pp_sort".$$op,$root,$start);
619 $init->add(sprintf("(%s)->op_next=%s;",$sym,$fakeop));
622 write_back_lexicals();
629 my $gvsym = $op->gv->save;
631 runtime("XPUSHs((SV*)$gvsym);");
637 my $gvsym = $op->gv->save;
639 if ($op->private & OPpLVAL_INTRO) {
640 runtime("XPUSHs(save_scalar($gvsym));");
642 runtime("XPUSHs(GvSV($gvsym));");
649 my $gvsym = $op->gv->save;
650 my $ix = $op->private;
651 my $flag = $op->flags & OPf_MOD;
653 runtime("svp = av_fetch(GvAV($gvsym), $ix, $flag);",
654 "PUSHs(svp ? *svp : &PL_sv_undef);");
659 my ($op, $operator) = @_;
660 if ($op->flags & OPf_STACKED) {
661 my $right = pop_int();
663 my $left = top_int();
664 $stack[-1]->set_int(&$operator($left, $right));
666 runtime(sprintf("sv_setiv(TOPs, %s);",&$operator("TOPi", $right)));
669 my $targ = $pad[$op->targ];
670 my $right = new B::Pseudoreg ("IV", "riv");
671 my $left = new B::Pseudoreg ("IV", "liv");
672 runtime(sprintf("$$right = %s; $$left = %s;", pop_int(), pop_int));
673 $targ->set_int(&$operator($$left, $$right));
679 sub INTS_CLOSED () { 0x1 }
680 sub INT_RESULT () { 0x2 }
681 sub NUMERIC_RESULT () { 0x4 }
684 my ($op, $operator, $flags) = @_;
686 $force_int ||= ($flags & INT_RESULT);
687 $force_int ||= ($flags & INTS_CLOSED && @stack >= 2
688 && valid_int($stack[-2]) && valid_int($stack[-1]));
689 if ($op->flags & OPf_STACKED) {
690 my $right = pop_numeric();
692 my $left = top_numeric();
694 $stack[-1]->set_int(&$operator($left, $right));
696 $stack[-1]->set_numeric(&$operator($left, $right));
700 my $rightruntime = new B::Pseudoreg ("IV", "riv");
701 runtime(sprintf("$$rightruntime = %s;",$right));
702 runtime(sprintf("sv_setiv(TOPs, %s);",
703 &$operator("TOPi", $$rightruntime)));
705 my $rightruntime = new B::Pseudoreg ("double", "rnv");
706 runtime(sprintf("$$rightruntime = %s;",$right));
707 runtime(sprintf("sv_setnv(TOPs, %s);",
708 &$operator("TOPn",$$rightruntime)));
712 my $targ = $pad[$op->targ];
713 $force_int ||= ($targ->{type} == T_INT);
715 my $right = new B::Pseudoreg ("IV", "riv");
716 my $left = new B::Pseudoreg ("IV", "liv");
717 runtime(sprintf("$$right = %s; $$left = %s;",
718 pop_numeric(), pop_numeric));
719 $targ->set_int(&$operator($$left, $$right));
721 my $right = new B::Pseudoreg ("double", "rnv");
722 my $left = new B::Pseudoreg ("double", "lnv");
723 runtime(sprintf("$$right = %s; $$left = %s;",
724 pop_numeric(), pop_numeric));
725 $targ->set_numeric(&$operator($$left, $$right));
734 if ($op->flags & OPf_STACKED) {
735 my $right = pop_numeric();
737 my $left = top_numeric();
738 runtime sprintf("if (%s > %s){",$left,$right);
739 $stack[-1]->set_int(1);
740 $stack[-1]->write_back();
741 runtime sprintf("}else if (%s < %s ) {",$left,$right);
742 $stack[-1]->set_int(-1);
743 $stack[-1]->write_back();
744 runtime sprintf("}else if (%s == %s) {",$left,$right);
745 $stack[-1]->set_int(0);
746 $stack[-1]->write_back();
747 runtime sprintf("}else {");
748 $stack[-1]->set_sv("&PL_sv_undef");
751 my $rightruntime = new B::Pseudoreg ("double", "rnv");
752 runtime(sprintf("$$rightruntime = %s;",$right));
753 runtime sprintf(qq/if ("TOPn" > %s){/,$rightruntime);
754 runtime sprintf("sv_setiv(TOPs,1);");
755 runtime sprintf(qq/}else if ( "TOPn" < %s ) {/,$$rightruntime);
756 runtime sprintf("sv_setiv(TOPs,-1);");
757 runtime sprintf(qq/} else if ("TOPn" == %s) {/,$$rightruntime);
758 runtime sprintf("sv_setiv(TOPs,0);");
759 runtime sprintf(qq/}else {/);
760 runtime sprintf("sv_setiv(TOPs,&PL_sv_undef;");
764 my $targ = $pad[$op->targ];
765 my $right = new B::Pseudoreg ("double", "rnv");
766 my $left = new B::Pseudoreg ("double", "lnv");
767 runtime(sprintf("$$right = %s; $$left = %s;",
768 pop_numeric(), pop_numeric));
769 runtime sprintf("if (%s > %s){",$$left,$$right);
772 runtime sprintf("}else if (%s < %s ) {",$$left,$$right);
775 runtime sprintf("}else if (%s == %s) {",$$left,$$right);
778 runtime sprintf("}else {");
779 $targ->set_sv("&PL_sv_undef");
787 my ($op, $operator, $flags) = @_;
788 if ($op->flags & OPf_STACKED) {
789 my $right = pop_sv();
792 if ($flags & INT_RESULT) {
793 $stack[-1]->set_int(&$operator($left, $right));
794 } elsif ($flags & NUMERIC_RESULT) {
795 $stack[-1]->set_numeric(&$operator($left, $right));
797 # XXX Does this work?
798 runtime(sprintf("sv_setsv($left, %s);",
799 &$operator($left, $right)));
800 $stack[-1]->invalidate;
804 if ($flags & INT_RESULT) {
806 } elsif ($flags & NUMERIC_RESULT) {
811 runtime(sprintf("%s(TOPs, %s);", $f, &$operator("TOPs", $right)));
814 my $targ = $pad[$op->targ];
815 runtime(sprintf("right = %s; left = %s;", pop_sv(), pop_sv));
816 if ($flags & INT_RESULT) {
817 $targ->set_int(&$operator("left", "right"));
818 } elsif ($flags & NUMERIC_RESULT) {
819 $targ->set_numeric(&$operator("left", "right"));
821 # XXX Does this work?
822 runtime(sprintf("sv_setsv(%s, %s);",
823 $targ->as_sv, &$operator("left", "right")));
832 my ($op, $operator) = @_;
833 my $right = new B::Pseudoreg ("IV", "riv");
834 my $left = new B::Pseudoreg ("IV", "liv");
835 runtime(sprintf("$$right = %s; $$left = %s;", pop_int(), pop_int()));
836 my $bool = new B::Stackobj::Bool (new B::Pseudoreg ("int", "b"));
837 $bool->set_int(&$operator($$left, $$right));
842 sub bool_numeric_binop {
843 my ($op, $operator) = @_;
844 my $right = new B::Pseudoreg ("double", "rnv");
845 my $left = new B::Pseudoreg ("double", "lnv");
846 runtime(sprintf("$$right = %s; $$left = %s;",
847 pop_numeric(), pop_numeric()));
848 my $bool = new B::Stackobj::Bool (new B::Pseudoreg ("int", "b"));
849 $bool->set_numeric(&$operator($$left, $$right));
855 my ($op, $operator) = @_;
856 runtime(sprintf("right = %s; left = %s;", pop_sv(), pop_sv()));
857 my $bool = new B::Stackobj::Bool (new B::Pseudoreg ("int", "b"));
858 $bool->set_numeric(&$operator("left", "right"));
865 return sub { "$_[0] $opname $_[1]" }
870 return sub { sprintf("%s(%s)", $opname, join(", ", @_)) }
874 my $plus_op = infix_op("+");
875 my $minus_op = infix_op("-");
876 my $multiply_op = infix_op("*");
877 my $divide_op = infix_op("/");
878 my $modulo_op = infix_op("%");
879 my $lshift_op = infix_op("<<");
880 my $rshift_op = infix_op(">>");
881 my $scmp_op = prefix_op("sv_cmp");
882 my $seq_op = prefix_op("sv_eq");
883 my $sne_op = prefix_op("!sv_eq");
884 my $slt_op = sub { "sv_cmp($_[0], $_[1]) < 0" };
885 my $sgt_op = sub { "sv_cmp($_[0], $_[1]) > 0" };
886 my $sle_op = sub { "sv_cmp($_[0], $_[1]) <= 0" };
887 my $sge_op = sub { "sv_cmp($_[0], $_[1]) >= 0" };
888 my $eq_op = infix_op("==");
889 my $ne_op = infix_op("!=");
890 my $lt_op = infix_op("<");
891 my $gt_op = infix_op(">");
892 my $le_op = infix_op("<=");
893 my $ge_op = infix_op(">=");
896 # XXX The standard perl PP code has extra handling for
897 # some special case arguments of these operators.
899 sub pp_add { numeric_binop($_[0], $plus_op, INTS_CLOSED) }
900 sub pp_subtract { numeric_binop($_[0], $minus_op, INTS_CLOSED) }
901 sub pp_multiply { numeric_binop($_[0], $multiply_op, INTS_CLOSED) }
902 sub pp_divide { numeric_binop($_[0], $divide_op) }
903 sub pp_modulo { int_binop($_[0], $modulo_op) } # differs from perl's
905 sub pp_left_shift { int_binop($_[0], $lshift_op) }
906 sub pp_right_shift { int_binop($_[0], $rshift_op) }
907 sub pp_i_add { int_binop($_[0], $plus_op) }
908 sub pp_i_subtract { int_binop($_[0], $minus_op) }
909 sub pp_i_multiply { int_binop($_[0], $multiply_op) }
910 sub pp_i_divide { int_binop($_[0], $divide_op) }
911 sub pp_i_modulo { int_binop($_[0], $modulo_op) }
913 sub pp_eq { bool_numeric_binop($_[0], $eq_op) }
914 sub pp_ne { bool_numeric_binop($_[0], $ne_op) }
915 sub pp_lt { bool_numeric_binop($_[0], $lt_op) }
916 sub pp_gt { bool_numeric_binop($_[0], $gt_op) }
917 sub pp_le { bool_numeric_binop($_[0], $le_op) }
918 sub pp_ge { bool_numeric_binop($_[0], $ge_op) }
920 sub pp_i_eq { bool_int_binop($_[0], $eq_op) }
921 sub pp_i_ne { bool_int_binop($_[0], $ne_op) }
922 sub pp_i_lt { bool_int_binop($_[0], $lt_op) }
923 sub pp_i_gt { bool_int_binop($_[0], $gt_op) }
924 sub pp_i_le { bool_int_binop($_[0], $le_op) }
925 sub pp_i_ge { bool_int_binop($_[0], $ge_op) }
927 sub pp_scmp { sv_binop($_[0], $scmp_op, INT_RESULT) }
928 sub pp_slt { bool_sv_binop($_[0], $slt_op) }
929 sub pp_sgt { bool_sv_binop($_[0], $sgt_op) }
930 sub pp_sle { bool_sv_binop($_[0], $sle_op) }
931 sub pp_sge { bool_sv_binop($_[0], $sge_op) }
932 sub pp_seq { bool_sv_binop($_[0], $seq_op) }
933 sub pp_sne { bool_sv_binop($_[0], $sne_op) }
939 my $backwards = $op->private & OPpASSIGN_BACKWARDS;
944 ($src, $dst) = ($dst, $src) if $backwards;
945 my $type = $src->{type};
946 if ($type == T_INT) {
947 $dst->set_int($src->as_int);
948 } elsif ($type == T_DOUBLE) {
949 $dst->set_numeric($src->as_numeric);
951 $dst->set_sv($src->as_sv);
954 } elsif (@stack == 1) {
956 my $src = pop @stack;
957 my $type = $src->{type};
958 runtime("if (PL_tainting && PL_tainted) TAINT_NOT;");
959 if ($type == T_INT) {
960 runtime sprintf("sv_setiv(TOPs, %s);", $src->as_int);
961 } elsif ($type == T_DOUBLE) {
962 runtime sprintf("sv_setnv(TOPs, %s);", $src->as_double);
964 runtime sprintf("sv_setsv(TOPs, %s);", $src->as_sv);
966 runtime("SvSETMAGIC(TOPs);");
968 my $dst = $stack[-1];
969 my $type = $dst->{type};
970 runtime("sv = POPs;");
971 runtime("MAYBE_TAINT_SASSIGN_SRC(sv);");
972 if ($type == T_INT) {
973 $dst->set_int("SvIV(sv)");
974 } elsif ($type == T_DOUBLE) {
975 $dst->set_double("SvNV(sv)");
977 runtime("SvSetMagicSV($dst->{sv}, sv);");
983 runtime("src = POPs; dst = TOPs;");
985 runtime("dst = POPs; src = TOPs;");
987 runtime("MAYBE_TAINT_SASSIGN_SRC(src);",
988 "SvSetSV(dst, src);",
998 my $obj = $stack[-1];
999 my $type = $obj->{type};
1000 if ($type == T_INT || $type == T_DOUBLE) {
1001 $obj->set_int($obj->as_int . " + 1");
1003 runtime sprintf("PP_PREINC(%s);", $obj->as_sv);
1007 runtime sprintf("PP_PREINC(TOPs);");
1015 runtime("PUSHMARK(sp);");
1022 my $gimme = gimme($op);
1023 if ($gimme == G_ARRAY) { # sic
1024 runtime("POPMARK;"); # need this even though not a "full" pp_list
1026 runtime("PP_LIST($gimme);");
1033 $curcop->write_back;
1034 write_back_lexicals(REGISTER|TEMPORARY);
1036 my $sym = doop($op);
1037 runtime("while (PL_op != ($sym)->op_next && PL_op != (OP*)0 ){");
1038 runtime("PL_op = (*PL_op->op_ppaddr)(aTHX);");
1039 runtime("SPAGAIN;}");
1041 invalidate_lexicals(REGISTER|TEMPORARY);
1046 my $ppname = $op->ppaddr;
1047 write_back_lexicals() unless $skip_lexicals{$ppname};
1048 write_back_stack() unless $skip_stack{$ppname};
1050 # See comment in pp_grepwhile to see why!
1051 $init->add("((LISTOP*)$sym)->op_first = $sym;");
1052 runtime("if (PL_op == ((LISTOP*)($sym))->op_first){");
1053 runtime( sprintf("goto %s;",label($op->first)));
1061 my $ppname = $op->ppaddr;
1062 write_back_lexicals() unless $skip_lexicals{$ppname};
1063 write_back_stack() unless $skip_stack{$ppname};
1065 runtime("if (PL_op != ($sym)->op_next && PL_op != (OP*)0){return PL_op;}");
1066 invalidate_lexicals() unless $skip_invalidate{$ppname};
1075 write_back_lexicals() unless $skip_lexicals{$ppname};
1076 write_back_stack() unless $skip_stack{$ppname};
1077 runtime("if (PL_curstackinfo->si_type == PERLSI_SORT){");
1078 runtime("\tPUTBACK;return 0;");
1085 write_back_lexicals(REGISTER|TEMPORARY);
1087 my $sym = doop($op);
1088 # XXX Is this the right way to distinguish between it returning
1089 # CvSTART(cv) (via doform) and pop_return()?
1090 #runtime("if (PL_op) PL_op = (*PL_op->op_ppaddr)(aTHX);");
1091 runtime("SPAGAIN;");
1093 invalidate_lexicals(REGISTER|TEMPORARY);
1099 $curcop->write_back;
1100 write_back_lexicals(REGISTER|TEMPORARY);
1102 my $sym = loadop($op);
1103 my $ppaddr = $op->ppaddr;
1104 runtime("PP_EVAL($ppaddr, ($sym)->op_next);");
1106 invalidate_lexicals(REGISTER|TEMPORARY);
1110 sub pp_entereval { doeval(@_) }
1111 sub pp_require { doeval(@_) }
1112 sub pp_dofile { doeval(@_) }
1116 $curcop->write_back;
1117 write_back_lexicals(REGISTER|TEMPORARY);
1119 my $sym = doop($op);
1120 my $jmpbuf = sprintf("jmpbuf%d", $jmpbuf_ix++);
1121 declare("JMPENV", $jmpbuf);
1122 runtime(sprintf("PP_ENTERTRY(%s,%s);", $jmpbuf, label($op->other->next)));
1123 invalidate_lexicals(REGISTER|TEMPORARY);
1130 runtime("PP_LEAVETRY;");
1136 if ($need_freetmps && $freetmps_each_loop) {
1137 runtime("FREETMPS;"); # otherwise the grepwhile loop messes things up
1144 my $nexttonext=$next->next;
1146 runtime(sprintf("if (PL_op == (($sym)->op_next)->op_next) goto %s;",
1147 label($nexttonext)));
1148 return $op->next->other;
1153 if ($need_freetmps && $freetmps_each_loop) {
1154 runtime("FREETMPS;"); # otherwise the mapwhile loop messes things up
1158 # pp_mapstart can return either op_next->op_next or op_next->op_other and
1159 # we need to be able to distinguish the two at runtime.
1163 my $nexttonext=$next->next;
1165 runtime(sprintf("if (PL_op == (($sym)->op_next)->op_next) goto %s;",
1166 label($nexttonext)));
1167 return $op->next->other;
1172 my $next = $op->next;
1173 unshift(@bblock_todo, $next);
1174 write_back_lexicals();
1176 my $sym = doop($op);
1177 # pp_grepwhile can return either op_next or op_other and we need to
1178 # be able to distinguish the two at runtime. Since it's possible for
1179 # both ops to be "inlined", the fields could both be zero. To get
1180 # around that, we hack op_next to be our own op (purely because we
1181 # know it's a non-NULL pointer and can't be the same as op_other).
1182 $init->add("((LOGOP*)$sym)->op_next = $sym;");
1183 runtime(sprintf("if (PL_op == ($sym)->op_next) goto %s;", label($next)));
1194 write_back_lexicals(REGISTER|TEMPORARY);
1197 runtime("PUTBACK;", "return PL_op;");
1204 warn sprintf("%s not yet implemented properly\n", $op->ppaddr);
1205 return default_pp($op);
1210 my $flags = $op->flags;
1211 if (!($flags & OPf_WANT)) {
1212 error("context of range unknown at compile-time");
1214 write_back_lexicals();
1216 unless (($flags & OPf_WANT)== OPf_WANT_LIST) {
1217 # We need to save our UNOP structure since pp_flop uses
1218 # it to find and adjust out targ. We don't need it ourselves.
1220 runtime sprintf("if (SvTRUE(PL_curpad[%d])) goto %s;",
1221 $op->targ, label($op->false));
1222 unshift(@bblock_todo, $op->false);
1229 my $flags = $op->flags;
1230 if (!($flags & OPf_WANT)) {
1231 error("context of flip unknown at compile-time");
1233 if (($flags & OPf_WANT)==OPf_WANT_LIST) {
1234 return $op->first->false;
1236 write_back_lexicals();
1238 # We need to save our UNOP structure since pp_flop uses
1239 # it to find and adjust out targ. We don't need it ourselves.
1242 my $rangeix = $op->first->targ;
1243 runtime(($op->private & OPpFLIP_LINENUM) ?
1244 "if (PL_last_in_gv && SvIV(TOPs) == IoLINES(GvIOp(PL_last_in_gv))) {"
1245 : "if (SvTRUE(TOPs)) {");
1246 runtime("\tsv_setiv(PL_curpad[$rangeix], 1);");
1247 if ($op->flags & OPf_SPECIAL) {
1248 runtime("sv_setiv(PL_curpad[$ix], 1);");
1250 runtime("\tsv_setiv(PL_curpad[$ix], 0);",
1252 sprintf("\tgoto %s;", label($op->first->false)));
1255 qq{sv_setpv(PL_curpad[$ix], "");},
1256 "SETs(PL_curpad[$ix]);");
1270 my $nextop = $op->nextop;
1271 my $lastop = $op->lastop;
1272 my $redoop = $op->redoop;
1273 $curcop->write_back;
1274 debug "enterloop: pushing on cxstack" if $debug_cxstack;
1278 "label" => $curcop->[0]->label,
1286 return default_pp($op);
1289 sub pp_enterloop { enterloop(@_) }
1290 sub pp_enteriter { enterloop(@_) }
1295 die "panic: leaveloop";
1297 debug "leaveloop: popping from cxstack" if $debug_cxstack;
1299 return default_pp($op);
1305 if ($op->flags & OPf_SPECIAL) {
1306 $cxix = dopoptoloop();
1308 error('"next" used outside loop');
1309 return $op->next; # ignore the op
1312 $cxix = dopoptolabel($op->pv);
1314 error('Label not found at compile time for "next %s"', $op->pv);
1315 return $op->next; # ignore the op
1319 my $nextop = $cxstack[$cxix]->{nextop};
1320 push(@bblock_todo, $nextop);
1321 runtime(sprintf("goto %s;", label($nextop)));
1328 if ($op->flags & OPf_SPECIAL) {
1329 $cxix = dopoptoloop();
1331 error('"redo" used outside loop');
1332 return $op->next; # ignore the op
1335 $cxix = dopoptolabel($op->pv);
1337 error('Label not found at compile time for "redo %s"', $op->pv);
1338 return $op->next; # ignore the op
1342 my $redoop = $cxstack[$cxix]->{redoop};
1343 push(@bblock_todo, $redoop);
1344 runtime(sprintf("goto %s;", label($redoop)));
1351 if ($op->flags & OPf_SPECIAL) {
1352 $cxix = dopoptoloop();
1354 error('"last" used outside loop');
1355 return $op->next; # ignore the op
1358 $cxix = dopoptolabel($op->pv);
1360 error('Label not found at compile time for "last %s"', $op->pv);
1361 return $op->next; # ignore the op
1363 # XXX Add support for "last" to leave non-loop blocks
1364 if ($cxstack[$cxix]->{type} != CXt_LOOP) {
1365 error('Use of "last" for non-loop blocks is not yet implemented');
1366 return $op->next; # ignore the op
1370 my $lastop = $cxstack[$cxix]->{lastop}->next;
1371 push(@bblock_todo, $lastop);
1372 runtime(sprintf("goto %s;", label($lastop)));
1378 write_back_lexicals();
1380 my $sym = doop($op);
1381 my $replroot = $op->pmreplroot;
1383 runtime sprintf("if (PL_op == ((PMOP*)(%s))->op_pmreplroot) goto %s;",
1384 $sym, label($replroot));
1385 $op->pmreplstart->save;
1386 push(@bblock_todo, $replroot);
1388 invalidate_lexicals();
1394 write_back_lexicals();
1397 my $pmop = $op->other;
1398 # warn sprintf("substcont: op = %s, pmop = %s\n",
1399 # peekop($op), peekop($pmop));#debug
1400 # my $pmopsym = objsym($pmop);
1401 my $pmopsym = $pmop->save; # XXX can this recurse?
1402 # warn "pmopsym = $pmopsym\n";#debug
1403 runtime sprintf("if (PL_op == ((PMOP*)(%s))->op_pmreplstart) goto %s;",
1404 $pmopsym, label($pmop->pmreplstart));
1405 invalidate_lexicals();
1411 my $ppname = $op->ppaddr;
1412 if ($curcop and $need_curcop{$ppname}){
1413 $curcop->write_back;
1415 write_back_lexicals() unless $skip_lexicals{$ppname};
1416 write_back_stack() unless $skip_stack{$ppname};
1418 # XXX If the only way that ops can write to a TEMPORARY lexical is
1419 # when it's named in $op->targ then we could call
1420 # invalidate_lexicals(TEMPORARY) and avoid having to write back all
1421 # the temporaries. For now, we'll play it safe and write back the lot.
1422 invalidate_lexicals() unless $skip_invalidate{$ppname};
1428 my $ppname = $op->ppaddr;
1429 if (exists $ignore_op{$ppname}) {
1432 debug peek_stack() if $debug_stack;
1434 debug sprintf("%s [%s]\n",
1436 $op->flags & OPf_STACKED ? "OPf_STACKED" : $op->targ);
1439 if (defined(&$ppname)) {
1441 return &$ppname($op);
1443 return default_pp($op);
1447 sub compile_bblock {
1449 #warn "compile_bblock: ", peekop($op), "\n"; # debug
1453 $op = compile_op($op);
1454 } while (defined($op) && $$op && !exists($leaders->{$$op}));
1455 write_back_stack(); # boo hoo: big loss
1461 my ($name, $root, $start, @padlist) = @_;
1465 B::Pseudoreg->new_scope;
1467 if ($debug_timings) {
1468 warn sprintf("Basic block analysis at %s\n", timing_info);
1470 $leaders = find_leaders($root, $start);
1471 my @leaders= keys %$leaders;
1472 if ($#leaders > -1) {
1473 @bblock_todo = ($start, values %$leaders) ;
1475 runtime("return PL_op?PL_op->op_next:0;");
1477 if ($debug_timings) {
1478 warn sprintf("Compilation at %s\n", timing_info);
1480 while (@bblock_todo) {
1481 $op = shift @bblock_todo;
1482 #warn sprintf("Considering basic block %s\n", peekop($op)); # debug
1483 next if !defined($op) || !$$op || $done{$$op};
1484 #warn "...compiling it\n"; # debug
1487 $op = compile_bblock($op);
1488 if ($need_freetmps && $freetmps_each_bblock) {
1489 runtime("FREETMPS;");
1492 } while defined($op) && $$op && !$done{$$op};
1493 if ($need_freetmps && $freetmps_each_loop) {
1494 runtime("FREETMPS;");
1498 runtime("PUTBACK;","return PL_op;");
1499 } elsif ($done{$$op}) {
1500 runtime(sprintf("goto %s;", label($op)));
1503 if ($debug_timings) {
1504 warn sprintf("Saving runtime at %s\n", timing_info);
1506 declare_pad(@padlist) ;
1513 $start = cc_queue(@_) if @_;
1514 while ($ccinfo = shift @cc_todo) {
1521 my ($name, $cvref) = @_;
1522 my $cv = svref_2object($cvref);
1523 my @padlist = $cv->PADLIST->ARRAY;
1524 my $curpad_sym = $padlist[1]->save;
1525 cc_recurse($name, $cv->ROOT, $cv->START, @padlist);
1529 my @comppadlist = comppadlist->ARRAY;
1530 my $curpad_nam = $comppadlist[0]->save;
1531 my $curpad_sym = $comppadlist[1]->save;
1532 my $init_av = init_av->save;
1533 my $start = cc_recurse("pp_main", main_root, main_start, @comppadlist);
1534 # Do save_unused_subs before saving inc_hv
1538 my $inc_hv = svref_2object(\%INC)->save;
1539 my $inc_av = svref_2object(\@INC)->save;
1540 my $amagic_generate= amagic_generation;
1542 if (!defined($module)) {
1543 $init->add(sprintf("PL_main_root = s\\_%x;", ${main_root()}),
1544 "PL_main_start = $start;",
1545 "PL_curpad = AvARRAY($curpad_sym);",
1546 "PL_initav = (AV *) $init_av;",
1547 "GvHV(PL_incgv) = $inc_hv;",
1548 "GvAV(PL_incgv) = $inc_av;",
1549 "av_store(CvPADLIST(PL_main_cv),0,SvREFCNT_inc($curpad_nam));",
1550 "av_store(CvPADLIST(PL_main_cv),1,SvREFCNT_inc($curpad_sym));",
1551 "PL_amagic_generation= $amagic_generate;",
1555 seek(STDOUT,0,0); #prevent print statements from BEGIN{} into the output
1556 output_boilerplate();
1558 output_all("perl_init");
1562 if (defined($module)) {
1563 my $cmodule = $module;
1564 $cmodule =~ s/::/__/g;
1574 SAVESPTR(PL_curpad);
1576 PL_curpad = AvARRAY($curpad_sym);
1586 if ($debug_timings) {
1587 warn sprintf("Done at %s\n", timing_info);
1593 my ($option, $opt, $arg);
1595 while ($option = shift @options) {
1596 if ($option =~ /^-(.)(.*)/) {
1600 unshift @options, $option;
1603 if ($opt eq "-" && $arg eq "-") {
1606 } elsif ($opt eq "o") {
1607 $arg ||= shift @options;
1608 open(STDOUT, ">$arg") or return "open '>$arg': $!\n";
1609 } elsif ($opt eq "n") {
1610 $arg ||= shift @options;
1611 $module_name = $arg;
1612 } elsif ($opt eq "u") {
1613 $arg ||= shift @options;
1614 mark_unused($arg,undef);
1615 } elsif ($opt eq "f") {
1616 $arg ||= shift @options;
1617 my $value = $arg !~ s/^no-//;
1619 my $ref = $optimise{$arg};
1620 if (defined($ref)) {
1623 warn qq(ignoring unknown optimisation option "$arg"\n);
1625 } elsif ($opt eq "O") {
1626 $arg = 1 if $arg eq "";
1628 foreach $ref (values %optimise) {
1632 $freetmps_each_loop = 1;
1635 $freetmps_each_bblock = 1 unless $freetmps_each_loop;
1637 } elsif ($opt eq "m") {
1638 $arg ||= shift @options;
1640 mark_unused($arg,undef);
1641 } elsif ($opt eq "p") {
1642 $arg ||= shift @options;
1644 } elsif ($opt eq "D") {
1645 $arg ||= shift @options;
1646 foreach $arg (split(//, $arg)) {
1649 } elsif ($arg eq "O") {
1651 } elsif ($arg eq "s") {
1653 } elsif ($arg eq "c") {
1655 } elsif ($arg eq "p") {
1657 } elsif ($arg eq "r") {
1659 } elsif ($arg eq "S") {
1661 } elsif ($arg eq "q") {
1663 } elsif ($arg eq "l") {
1665 } elsif ($arg eq "t") {
1672 $init = B::Section->get("init");
1673 $decl = B::Section->get("decl");
1677 my ($objname, $ppname);
1678 foreach $objname (@options) {
1679 $objname = "main::$objname" unless $objname =~ /::/;
1680 ($ppname = $objname) =~ s/^.*?:://;
1681 eval "cc_obj(qq(pp_sub_$ppname), \\&$objname)";
1682 die "cc_obj(qq(pp_sub_$ppname, \\&$objname) failed: $@" if $@;
1685 output_boilerplate();
1687 output_all($module_name || "init_module");
1691 return sub { cc_main() };
1701 B::CC - Perl compiler's optimized C translation backend
1705 perl -MO=CC[,OPTIONS] foo.pl
1709 This compiler backend takes Perl source and generates C source code
1710 corresponding to the flow of your program. In other words, this
1711 backend is somewhat a "real" compiler in the sense that many people
1712 think about compilers. Note however that, currently, it is a very
1713 poor compiler in that although it generates (mostly, or at least
1714 sometimes) correct code, it performs relatively few optimisations.
1715 This will change as the compiler develops. The result is that
1716 running an executable compiled with this backend may start up more
1717 quickly than running the original Perl program (a feature shared
1718 by the B<C> compiler backend--see F<B::C>) and may also execute
1719 slightly faster. This is by no means a good optimising compiler--yet.
1723 If there are any non-option arguments, they are taken to be
1724 names of objects to be saved (probably doesn't work properly yet).
1725 Without extra arguments, it saves the main program.
1731 Output to filename instead of STDOUT
1735 Verbose compilation (currently gives a few compilation statistics).
1739 Force end of options
1743 Force apparently unused subs from package Packname to be compiled.
1744 This allows programs to use eval "foo()" even when sub foo is never
1745 seen to be used at compile time. The down side is that any subs which
1746 really are never used also have code generated. This option is
1747 necessary, for example, if you have a signal handler foo which you
1748 initialise with C<$SIG{BAR} = "foo">. A better fix, though, is just
1749 to change it to C<$SIG{BAR} = \&foo>. You can have multiple B<-u>
1750 options. The compiler tries to figure out which packages may possibly
1751 have subs in which need compiling but the current version doesn't do
1752 it very well. In particular, it is confused by nested packages (i.e.
1753 of the form C<A::B>) where package C<A> does not contain any subs.
1755 =item B<-mModulename>
1757 Instead of generating source for a runnable executable, generate
1758 source for an XSUB module. The boot_Modulename function (which
1759 DynaLoader can look for) does the appropriate initialisation and runs
1760 the main part of the Perl source that is being compiled.
1765 Debug options (concatenated or separate flags like C<perl -D>).
1769 Writes debugging output to STDERR just as it's about to write to the
1770 program's runtime (otherwise writes debugging info as comments in
1775 Outputs each OP as it's compiled
1779 Outputs the contents of the shadow stack at each OP
1783 Outputs the contents of the shadow pad of lexicals as it's loaded for
1784 each sub or the main program.
1788 Outputs the name of each fake PP function in the queue as it's about
1793 Output the filename and line number of each original line of Perl
1794 code as it's processed (C<pp_nextstate>).
1798 Outputs timing information of compilation stages.
1802 Force optimisations on or off one at a time.
1804 =item B<-ffreetmps-each-bblock>
1806 Delays FREETMPS from the end of each statement to the end of the each
1809 =item B<-ffreetmps-each-loop>
1811 Delays FREETMPS from the end of each statement to the end of the group
1812 of basic blocks forming a loop. At most one of the freetmps-each-*
1813 options can be used.
1815 =item B<-fomit-taint>
1817 Omits generating code for handling perl's tainting mechanism.
1821 Optimisation level (n = 0, 1, 2, ...). B<-O> means B<-O1>.
1822 Currently, B<-O1> sets B<-ffreetmps-each-bblock> and B<-O2>
1823 sets B<-ffreetmps-each-loop>.
1829 perl -MO=CC,-O2,-ofoo.c foo.pl
1830 perl cc_harness -o foo foo.c
1832 Note that C<cc_harness> lives in the C<B> subdirectory of your perl
1833 library directory. The utility called C<perlcc> may also be used to
1834 help make use of this compiler.
1836 perl -MO=CC,-mFoo,-oFoo.c Foo.pm
1837 perl cc_harness -shared -c -o Foo.so Foo.c
1841 Plenty. Current status: experimental.
1845 These aren't really bugs but they are constructs which are heavily
1846 tied to perl's compile-and-go implementation and with which this
1847 compiler backend cannot cope.
1851 Standard perl calculates the target of "next", "last", and "redo"
1852 at run-time. The compiler calculates the targets at compile-time.
1853 For example, the program
1855 sub skip_on_odd { next NUMBER if $_[0] % 2 }
1856 NUMBER: for ($i = 0; $i < 5; $i++) {
1865 with standard perl but gives a compile-time error with the compiler.
1867 =head2 Context of ".."
1869 The context (scalar or array) of the ".." operator determines whether
1870 it behaves as a range or a flip/flop. Standard perl delays until
1871 runtime the decision of which context it is in but the compiler needs
1872 to know the context at compile-time. For example,
1875 sub range { (shift @a)..(shift @a) }
1877 while (@a) { print scalar(range()) }
1879 generates the output
1883 with standard Perl but gives a compile-time error with compiled Perl.
1887 Compiled Perl programs use native C arithemtic much more frequently
1888 than standard perl. Operations on large numbers or on boundary
1889 cases may produce different behaviour.
1891 =head2 Deprecated features
1893 Features of standard perl such as C<$[> which have been deprecated
1894 in standard perl since Perl5 was released have not been implemented
1899 Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>