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], $plus_op) }
900 sub pp_subtract { numeric_binop($_[0], $minus_op) }
901 sub pp_multiply { numeric_binop($_[0], $multiply_op) }
902 sub pp_divide { numeric_binop($_[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,$src->{flags} & VALID_UNSIGNED);
948 } elsif ($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 if ($src->{flags} & VALID_UNSIGNED){
961 runtime sprintf("sv_setuv(TOPs, %s);", $src->as_int);
963 runtime sprintf("sv_setiv(TOPs, %s);", $src->as_int);
965 } elsif ($type == T_DOUBLE) {
966 runtime sprintf("sv_setnv(TOPs, %s);", $src->as_double);
968 runtime sprintf("sv_setsv(TOPs, %s);", $src->as_sv);
970 runtime("SvSETMAGIC(TOPs);");
972 my $dst = $stack[-1];
973 my $type = $dst->{type};
974 runtime("sv = POPs;");
975 runtime("MAYBE_TAINT_SASSIGN_SRC(sv);");
976 if ($type == T_INT) {
977 $dst->set_int("SvIV(sv)");
978 } elsif ($type == T_DOUBLE) {
979 $dst->set_double("SvNV(sv)");
981 runtime("SvSetMagicSV($dst->{sv}, sv);");
987 runtime("src = POPs; dst = TOPs;");
989 runtime("dst = POPs; src = TOPs;");
991 runtime("MAYBE_TAINT_SASSIGN_SRC(src);",
992 "SvSetSV(dst, src);",
1002 my $obj = $stack[-1];
1003 my $type = $obj->{type};
1004 if ($type == T_INT || $type == T_DOUBLE) {
1005 $obj->set_int($obj->as_int . " + 1");
1007 runtime sprintf("PP_PREINC(%s);", $obj->as_sv);
1011 runtime sprintf("PP_PREINC(TOPs);");
1019 runtime("PUSHMARK(sp);");
1026 my $gimme = gimme($op);
1027 if ($gimme == G_ARRAY) { # sic
1028 runtime("POPMARK;"); # need this even though not a "full" pp_list
1030 runtime("PP_LIST($gimme);");
1037 $curcop->write_back;
1038 write_back_lexicals(REGISTER|TEMPORARY);
1040 my $sym = doop($op);
1041 runtime("while (PL_op != ($sym)->op_next && PL_op != (OP*)0 ){");
1042 runtime("PL_op = (*PL_op->op_ppaddr)(aTHX);");
1043 runtime("SPAGAIN;}");
1045 invalidate_lexicals(REGISTER|TEMPORARY);
1050 my $ppname = $op->ppaddr;
1051 write_back_lexicals() unless $skip_lexicals{$ppname};
1052 write_back_stack() unless $skip_stack{$ppname};
1054 # See comment in pp_grepwhile to see why!
1055 $init->add("((LISTOP*)$sym)->op_first = $sym;");
1056 runtime("if (PL_op == ((LISTOP*)($sym))->op_first){");
1057 runtime( sprintf("goto %s;",label($op->first)));
1065 my $ppname = $op->ppaddr;
1066 write_back_lexicals() unless $skip_lexicals{$ppname};
1067 write_back_stack() unless $skip_stack{$ppname};
1069 runtime("if (PL_op != ($sym)->op_next && PL_op != (OP*)0){return PL_op;}");
1070 invalidate_lexicals() unless $skip_invalidate{$ppname};
1079 write_back_lexicals() unless $skip_lexicals{$ppname};
1080 write_back_stack() unless $skip_stack{$ppname};
1081 runtime("if (PL_curstackinfo->si_type == PERLSI_SORT){");
1082 runtime("\tPUTBACK;return 0;");
1089 write_back_lexicals(REGISTER|TEMPORARY);
1091 my $sym = doop($op);
1092 # XXX Is this the right way to distinguish between it returning
1093 # CvSTART(cv) (via doform) and pop_return()?
1094 #runtime("if (PL_op) PL_op = (*PL_op->op_ppaddr)(aTHX);");
1095 runtime("SPAGAIN;");
1097 invalidate_lexicals(REGISTER|TEMPORARY);
1103 $curcop->write_back;
1104 write_back_lexicals(REGISTER|TEMPORARY);
1106 my $sym = loadop($op);
1107 my $ppaddr = $op->ppaddr;
1108 runtime("PP_EVAL($ppaddr, ($sym)->op_next);");
1110 invalidate_lexicals(REGISTER|TEMPORARY);
1114 sub pp_entereval { doeval(@_) }
1115 sub pp_require { doeval(@_) }
1116 sub pp_dofile { doeval(@_) }
1120 $curcop->write_back;
1121 write_back_lexicals(REGISTER|TEMPORARY);
1123 my $sym = doop($op);
1124 my $jmpbuf = sprintf("jmpbuf%d", $jmpbuf_ix++);
1125 declare("JMPENV", $jmpbuf);
1126 runtime(sprintf("PP_ENTERTRY(%s,%s);", $jmpbuf, label($op->other->next)));
1127 invalidate_lexicals(REGISTER|TEMPORARY);
1134 runtime("PP_LEAVETRY;");
1140 if ($need_freetmps && $freetmps_each_loop) {
1141 runtime("FREETMPS;"); # otherwise the grepwhile loop messes things up
1148 my $nexttonext=$next->next;
1150 runtime(sprintf("if (PL_op == (($sym)->op_next)->op_next) goto %s;",
1151 label($nexttonext)));
1152 return $op->next->other;
1157 if ($need_freetmps && $freetmps_each_loop) {
1158 runtime("FREETMPS;"); # otherwise the mapwhile loop messes things up
1162 # pp_mapstart can return either op_next->op_next or op_next->op_other and
1163 # we need to be able to distinguish the two at runtime.
1167 my $nexttonext=$next->next;
1169 runtime(sprintf("if (PL_op == (($sym)->op_next)->op_next) goto %s;",
1170 label($nexttonext)));
1171 return $op->next->other;
1176 my $next = $op->next;
1177 unshift(@bblock_todo, $next);
1178 write_back_lexicals();
1180 my $sym = doop($op);
1181 # pp_grepwhile can return either op_next or op_other and we need to
1182 # be able to distinguish the two at runtime. Since it's possible for
1183 # both ops to be "inlined", the fields could both be zero. To get
1184 # around that, we hack op_next to be our own op (purely because we
1185 # know it's a non-NULL pointer and can't be the same as op_other).
1186 $init->add("((LOGOP*)$sym)->op_next = $sym;");
1187 runtime(sprintf("if (PL_op == ($sym)->op_next) goto %s;", label($next)));
1198 write_back_lexicals(REGISTER|TEMPORARY);
1201 runtime("PUTBACK;", "return PL_op;");
1208 warn sprintf("%s not yet implemented properly\n", $op->ppaddr);
1209 return default_pp($op);
1214 my $flags = $op->flags;
1215 if (!($flags & OPf_WANT)) {
1216 error("context of range unknown at compile-time");
1218 write_back_lexicals();
1220 unless (($flags & OPf_WANT)== OPf_WANT_LIST) {
1221 # We need to save our UNOP structure since pp_flop uses
1222 # it to find and adjust out targ. We don't need it ourselves.
1224 runtime sprintf("if (SvTRUE(PL_curpad[%d])) goto %s;",
1225 $op->targ, label($op->false));
1226 unshift(@bblock_todo, $op->false);
1233 my $flags = $op->flags;
1234 if (!($flags & OPf_WANT)) {
1235 error("context of flip unknown at compile-time");
1237 if (($flags & OPf_WANT)==OPf_WANT_LIST) {
1238 return $op->first->false;
1240 write_back_lexicals();
1242 # We need to save our UNOP structure since pp_flop uses
1243 # it to find and adjust out targ. We don't need it ourselves.
1246 my $rangeix = $op->first->targ;
1247 runtime(($op->private & OPpFLIP_LINENUM) ?
1248 "if (PL_last_in_gv && SvIV(TOPs) == IoLINES(GvIOp(PL_last_in_gv))) {"
1249 : "if (SvTRUE(TOPs)) {");
1250 runtime("\tsv_setiv(PL_curpad[$rangeix], 1);");
1251 if ($op->flags & OPf_SPECIAL) {
1252 runtime("sv_setiv(PL_curpad[$ix], 1);");
1254 runtime("\tsv_setiv(PL_curpad[$ix], 0);",
1256 sprintf("\tgoto %s;", label($op->first->false)));
1259 qq{sv_setpv(PL_curpad[$ix], "");},
1260 "SETs(PL_curpad[$ix]);");
1274 my $nextop = $op->nextop;
1275 my $lastop = $op->lastop;
1276 my $redoop = $op->redoop;
1277 $curcop->write_back;
1278 debug "enterloop: pushing on cxstack" if $debug_cxstack;
1282 "label" => $curcop->[0]->label,
1290 return default_pp($op);
1293 sub pp_enterloop { enterloop(@_) }
1294 sub pp_enteriter { enterloop(@_) }
1299 die "panic: leaveloop";
1301 debug "leaveloop: popping from cxstack" if $debug_cxstack;
1303 return default_pp($op);
1309 if ($op->flags & OPf_SPECIAL) {
1310 $cxix = dopoptoloop();
1312 error('"next" used outside loop');
1313 return $op->next; # ignore the op
1316 $cxix = dopoptolabel($op->pv);
1318 error('Label not found at compile time for "next %s"', $op->pv);
1319 return $op->next; # ignore the op
1323 my $nextop = $cxstack[$cxix]->{nextop};
1324 push(@bblock_todo, $nextop);
1325 runtime(sprintf("goto %s;", label($nextop)));
1332 if ($op->flags & OPf_SPECIAL) {
1333 $cxix = dopoptoloop();
1335 error('"redo" used outside loop');
1336 return $op->next; # ignore the op
1339 $cxix = dopoptolabel($op->pv);
1341 error('Label not found at compile time for "redo %s"', $op->pv);
1342 return $op->next; # ignore the op
1346 my $redoop = $cxstack[$cxix]->{redoop};
1347 push(@bblock_todo, $redoop);
1348 runtime(sprintf("goto %s;", label($redoop)));
1355 if ($op->flags & OPf_SPECIAL) {
1356 $cxix = dopoptoloop();
1358 error('"last" used outside loop');
1359 return $op->next; # ignore the op
1362 $cxix = dopoptolabel($op->pv);
1364 error('Label not found at compile time for "last %s"', $op->pv);
1365 return $op->next; # ignore the op
1367 # XXX Add support for "last" to leave non-loop blocks
1368 if ($cxstack[$cxix]->{type} != CXt_LOOP) {
1369 error('Use of "last" for non-loop blocks is not yet implemented');
1370 return $op->next; # ignore the op
1374 my $lastop = $cxstack[$cxix]->{lastop}->next;
1375 push(@bblock_todo, $lastop);
1376 runtime(sprintf("goto %s;", label($lastop)));
1382 write_back_lexicals();
1384 my $sym = doop($op);
1385 my $replroot = $op->pmreplroot;
1387 runtime sprintf("if (PL_op == ((PMOP*)(%s))->op_pmreplroot) goto %s;",
1388 $sym, label($replroot));
1389 $op->pmreplstart->save;
1390 push(@bblock_todo, $replroot);
1392 invalidate_lexicals();
1398 write_back_lexicals();
1401 my $pmop = $op->other;
1402 # warn sprintf("substcont: op = %s, pmop = %s\n",
1403 # peekop($op), peekop($pmop));#debug
1404 # my $pmopsym = objsym($pmop);
1405 my $pmopsym = $pmop->save; # XXX can this recurse?
1406 # warn "pmopsym = $pmopsym\n";#debug
1407 runtime sprintf("if (PL_op == ((PMOP*)(%s))->op_pmreplstart) goto %s;",
1408 $pmopsym, label($pmop->pmreplstart));
1409 invalidate_lexicals();
1415 my $ppname = $op->ppaddr;
1416 if ($curcop and $need_curcop{$ppname}){
1417 $curcop->write_back;
1419 write_back_lexicals() unless $skip_lexicals{$ppname};
1420 write_back_stack() unless $skip_stack{$ppname};
1422 # XXX If the only way that ops can write to a TEMPORARY lexical is
1423 # when it's named in $op->targ then we could call
1424 # invalidate_lexicals(TEMPORARY) and avoid having to write back all
1425 # the temporaries. For now, we'll play it safe and write back the lot.
1426 invalidate_lexicals() unless $skip_invalidate{$ppname};
1432 my $ppname = $op->ppaddr;
1433 if (exists $ignore_op{$ppname}) {
1436 debug peek_stack() if $debug_stack;
1438 debug sprintf("%s [%s]\n",
1440 $op->flags & OPf_STACKED ? "OPf_STACKED" : $op->targ);
1443 if (defined(&$ppname)) {
1445 return &$ppname($op);
1447 return default_pp($op);
1451 sub compile_bblock {
1453 #warn "compile_bblock: ", peekop($op), "\n"; # debug
1457 $op = compile_op($op);
1458 } while (defined($op) && $$op && !exists($leaders->{$$op}));
1459 write_back_stack(); # boo hoo: big loss
1465 my ($name, $root, $start, @padlist) = @_;
1469 B::Pseudoreg->new_scope;
1471 if ($debug_timings) {
1472 warn sprintf("Basic block analysis at %s\n", timing_info);
1474 $leaders = find_leaders($root, $start);
1475 my @leaders= keys %$leaders;
1476 if ($#leaders > -1) {
1477 @bblock_todo = ($start, values %$leaders) ;
1479 runtime("return PL_op?PL_op->op_next:0;");
1481 if ($debug_timings) {
1482 warn sprintf("Compilation at %s\n", timing_info);
1484 while (@bblock_todo) {
1485 $op = shift @bblock_todo;
1486 #warn sprintf("Considering basic block %s\n", peekop($op)); # debug
1487 next if !defined($op) || !$$op || $done{$$op};
1488 #warn "...compiling it\n"; # debug
1491 $op = compile_bblock($op);
1492 if ($need_freetmps && $freetmps_each_bblock) {
1493 runtime("FREETMPS;");
1496 } while defined($op) && $$op && !$done{$$op};
1497 if ($need_freetmps && $freetmps_each_loop) {
1498 runtime("FREETMPS;");
1502 runtime("PUTBACK;","return PL_op;");
1503 } elsif ($done{$$op}) {
1504 runtime(sprintf("goto %s;", label($op)));
1507 if ($debug_timings) {
1508 warn sprintf("Saving runtime at %s\n", timing_info);
1510 declare_pad(@padlist) ;
1517 $start = cc_queue(@_) if @_;
1518 while ($ccinfo = shift @cc_todo) {
1525 my ($name, $cvref) = @_;
1526 my $cv = svref_2object($cvref);
1527 my @padlist = $cv->PADLIST->ARRAY;
1528 my $curpad_sym = $padlist[1]->save;
1529 cc_recurse($name, $cv->ROOT, $cv->START, @padlist);
1533 my @comppadlist = comppadlist->ARRAY;
1534 my $curpad_nam = $comppadlist[0]->save;
1535 my $curpad_sym = $comppadlist[1]->save;
1536 my $init_av = init_av->save;
1537 my $start = cc_recurse("pp_main", main_root, main_start, @comppadlist);
1538 # Do save_unused_subs before saving inc_hv
1542 my $inc_hv = svref_2object(\%INC)->save;
1543 my $inc_av = svref_2object(\@INC)->save;
1544 my $amagic_generate= amagic_generation;
1546 if (!defined($module)) {
1547 $init->add(sprintf("PL_main_root = s\\_%x;", ${main_root()}),
1548 "PL_main_start = $start;",
1549 "PL_curpad = AvARRAY($curpad_sym);",
1550 "PL_initav = (AV *) $init_av;",
1551 "GvHV(PL_incgv) = $inc_hv;",
1552 "GvAV(PL_incgv) = $inc_av;",
1553 "av_store(CvPADLIST(PL_main_cv),0,SvREFCNT_inc($curpad_nam));",
1554 "av_store(CvPADLIST(PL_main_cv),1,SvREFCNT_inc($curpad_sym));",
1555 "PL_amagic_generation= $amagic_generate;",
1559 seek(STDOUT,0,0); #prevent print statements from BEGIN{} into the output
1560 output_boilerplate();
1562 output_all("perl_init");
1566 if (defined($module)) {
1567 my $cmodule = $module;
1568 $cmodule =~ s/::/__/g;
1578 SAVESPTR(PL_curpad);
1580 PL_curpad = AvARRAY($curpad_sym);
1590 if ($debug_timings) {
1591 warn sprintf("Done at %s\n", timing_info);
1597 my ($option, $opt, $arg);
1599 while ($option = shift @options) {
1600 if ($option =~ /^-(.)(.*)/) {
1604 unshift @options, $option;
1607 if ($opt eq "-" && $arg eq "-") {
1610 } elsif ($opt eq "o") {
1611 $arg ||= shift @options;
1612 open(STDOUT, ">$arg") or return "open '>$arg': $!\n";
1613 } elsif ($opt eq "n") {
1614 $arg ||= shift @options;
1615 $module_name = $arg;
1616 } elsif ($opt eq "u") {
1617 $arg ||= shift @options;
1618 mark_unused($arg,undef);
1619 } elsif ($opt eq "f") {
1620 $arg ||= shift @options;
1621 my $value = $arg !~ s/^no-//;
1623 my $ref = $optimise{$arg};
1624 if (defined($ref)) {
1627 warn qq(ignoring unknown optimisation option "$arg"\n);
1629 } elsif ($opt eq "O") {
1630 $arg = 1 if $arg eq "";
1632 foreach $ref (values %optimise) {
1636 $freetmps_each_loop = 1;
1639 $freetmps_each_bblock = 1 unless $freetmps_each_loop;
1641 } elsif ($opt eq "m") {
1642 $arg ||= shift @options;
1644 mark_unused($arg,undef);
1645 } elsif ($opt eq "p") {
1646 $arg ||= shift @options;
1648 } elsif ($opt eq "D") {
1649 $arg ||= shift @options;
1650 foreach $arg (split(//, $arg)) {
1653 } elsif ($arg eq "O") {
1655 } elsif ($arg eq "s") {
1657 } elsif ($arg eq "c") {
1659 } elsif ($arg eq "p") {
1661 } elsif ($arg eq "r") {
1663 } elsif ($arg eq "S") {
1665 } elsif ($arg eq "q") {
1667 } elsif ($arg eq "l") {
1669 } elsif ($arg eq "t") {
1676 $init = B::Section->get("init");
1677 $decl = B::Section->get("decl");
1681 my ($objname, $ppname);
1682 foreach $objname (@options) {
1683 $objname = "main::$objname" unless $objname =~ /::/;
1684 ($ppname = $objname) =~ s/^.*?:://;
1685 eval "cc_obj(qq(pp_sub_$ppname), \\&$objname)";
1686 die "cc_obj(qq(pp_sub_$ppname, \\&$objname) failed: $@" if $@;
1689 output_boilerplate();
1691 output_all($module_name || "init_module");
1695 return sub { cc_main() };
1705 B::CC - Perl compiler's optimized C translation backend
1709 perl -MO=CC[,OPTIONS] foo.pl
1713 This compiler backend takes Perl source and generates C source code
1714 corresponding to the flow of your program. In other words, this
1715 backend is somewhat a "real" compiler in the sense that many people
1716 think about compilers. Note however that, currently, it is a very
1717 poor compiler in that although it generates (mostly, or at least
1718 sometimes) correct code, it performs relatively few optimisations.
1719 This will change as the compiler develops. The result is that
1720 running an executable compiled with this backend may start up more
1721 quickly than running the original Perl program (a feature shared
1722 by the B<C> compiler backend--see F<B::C>) and may also execute
1723 slightly faster. This is by no means a good optimising compiler--yet.
1727 If there are any non-option arguments, they are taken to be
1728 names of objects to be saved (probably doesn't work properly yet).
1729 Without extra arguments, it saves the main program.
1735 Output to filename instead of STDOUT
1739 Verbose compilation (currently gives a few compilation statistics).
1743 Force end of options
1747 Force apparently unused subs from package Packname to be compiled.
1748 This allows programs to use eval "foo()" even when sub foo is never
1749 seen to be used at compile time. The down side is that any subs which
1750 really are never used also have code generated. This option is
1751 necessary, for example, if you have a signal handler foo which you
1752 initialise with C<$SIG{BAR} = "foo">. A better fix, though, is just
1753 to change it to C<$SIG{BAR} = \&foo>. You can have multiple B<-u>
1754 options. The compiler tries to figure out which packages may possibly
1755 have subs in which need compiling but the current version doesn't do
1756 it very well. In particular, it is confused by nested packages (i.e.
1757 of the form C<A::B>) where package C<A> does not contain any subs.
1759 =item B<-mModulename>
1761 Instead of generating source for a runnable executable, generate
1762 source for an XSUB module. The boot_Modulename function (which
1763 DynaLoader can look for) does the appropriate initialisation and runs
1764 the main part of the Perl source that is being compiled.
1769 Debug options (concatenated or separate flags like C<perl -D>).
1773 Writes debugging output to STDERR just as it's about to write to the
1774 program's runtime (otherwise writes debugging info as comments in
1779 Outputs each OP as it's compiled
1783 Outputs the contents of the shadow stack at each OP
1787 Outputs the contents of the shadow pad of lexicals as it's loaded for
1788 each sub or the main program.
1792 Outputs the name of each fake PP function in the queue as it's about
1797 Output the filename and line number of each original line of Perl
1798 code as it's processed (C<pp_nextstate>).
1802 Outputs timing information of compilation stages.
1806 Force optimisations on or off one at a time.
1808 =item B<-ffreetmps-each-bblock>
1810 Delays FREETMPS from the end of each statement to the end of the each
1813 =item B<-ffreetmps-each-loop>
1815 Delays FREETMPS from the end of each statement to the end of the group
1816 of basic blocks forming a loop. At most one of the freetmps-each-*
1817 options can be used.
1819 =item B<-fomit-taint>
1821 Omits generating code for handling perl's tainting mechanism.
1825 Optimisation level (n = 0, 1, 2, ...). B<-O> means B<-O1>.
1826 Currently, B<-O1> sets B<-ffreetmps-each-bblock> and B<-O2>
1827 sets B<-ffreetmps-each-loop>.
1833 perl -MO=CC,-O2,-ofoo.c foo.pl
1834 perl cc_harness -o foo foo.c
1836 Note that C<cc_harness> lives in the C<B> subdirectory of your perl
1837 library directory. The utility called C<perlcc> may also be used to
1838 help make use of this compiler.
1840 perl -MO=CC,-mFoo,-oFoo.c Foo.pm
1841 perl cc_harness -shared -c -o Foo.so Foo.c
1845 Plenty. Current status: experimental.
1849 These aren't really bugs but they are constructs which are heavily
1850 tied to perl's compile-and-go implementation and with which this
1851 compiler backend cannot cope.
1855 Standard perl calculates the target of "next", "last", and "redo"
1856 at run-time. The compiler calculates the targets at compile-time.
1857 For example, the program
1859 sub skip_on_odd { next NUMBER if $_[0] % 2 }
1860 NUMBER: for ($i = 0; $i < 5; $i++) {
1869 with standard perl but gives a compile-time error with the compiler.
1871 =head2 Context of ".."
1873 The context (scalar or array) of the ".." operator determines whether
1874 it behaves as a range or a flip/flop. Standard perl delays until
1875 runtime the decision of which context it is in but the compiler needs
1876 to know the context at compile-time. For example,
1879 sub range { (shift @a)..(shift @a) }
1881 while (@a) { print scalar(range()) }
1883 generates the output
1887 with standard Perl but gives a compile-time error with compiled Perl.
1891 Compiled Perl programs use native C arithemtic much more frequently
1892 than standard perl. Operations on large numbers or on boundary
1893 cases may produce different behaviour.
1895 =head2 Deprecated features
1897 Features of standard perl such as C<$[> which have been deprecated
1898 in standard perl since Perl5 was released have not been implemented
1903 Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>