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a798dbf2 MB |
1 | # B.pm |
2 | # | |
1a52ab62 | 3 | # Copyright (c) 1996, 1997, 1998 Malcolm Beattie |
a798dbf2 MB |
4 | # |
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. | |
7 | # | |
8 | package B; | |
28b605d8 | 9 | |
a0da4400 | 10 | our $VERSION = '1.25'; |
28b605d8 | 11 | |
da4061d3 | 12 | require XSLoader; |
a798dbf2 | 13 | require Exporter; |
9426adcd | 14 | @ISA = qw(Exporter); |
b2590c4e | 15 | |
f72d64f0 DC |
16 | # walkoptree_slow comes from B.pm (you are there), |
17 | # walkoptree comes from B.xs | |
f6c2d85b JH |
18 | @EXPORT_OK = qw(minus_c ppname save_BEGINs |
19 | class peekop cast_I32 cstring cchar hash threadsv_names | |
b2590c4e | 20 | main_root main_start main_cv svref_2object opnumber |
5ce57cc0 | 21 | sub_generation amagic_generation perlstring |
f6c2d85b JH |
22 | walkoptree_slow walkoptree walkoptree_exec walksymtable |
23 | parents comppadlist sv_undef compile_stats timing_info | |
e412117e | 24 | begin_av init_av check_av end_av regex_padav dowarn defstash |
baccf54f | 25 | curstash warnhook diehook inc_gv @optype @specialsv_name |
651aa52e | 26 | ); |
e412117e | 27 | push @EXPORT_OK, qw(unitcheck_av) if $] > 5.009; |
b2590c4e | 28 | |
4c1f658f | 29 | sub OPf_KIDS (); |
a798dbf2 MB |
30 | use strict; |
31 | @B::SV::ISA = 'B::OBJECT'; | |
32 | @B::NULL::ISA = 'B::SV'; | |
33 | @B::PV::ISA = 'B::SV'; | |
34 | @B::IV::ISA = 'B::SV'; | |
4edc9001 | 35 | @B::NV::ISA = 'B::SV'; |
4df7f6af | 36 | # RV is eliminated with 5.11.0, but effectively is a specialisation of IV now. |
3ce3ed55 | 37 | @B::RV::ISA = $] >= 5.011 ? 'B::IV' : 'B::SV'; |
a798dbf2 | 38 | @B::PVIV::ISA = qw(B::PV B::IV); |
4edc9001 | 39 | @B::PVNV::ISA = qw(B::PVIV B::NV); |
a798dbf2 | 40 | @B::PVMG::ISA = 'B::PVNV'; |
5c35adbb | 41 | @B::REGEXP::ISA = 'B::PVMG' if $] >= 5.011; |
a01b8a53 | 42 | # Change in the inheritance hierarchy post 5.9.0 |
f5ba1307 | 43 | @B::PVLV::ISA = $] > 5.009 ? 'B::GV' : 'B::PVMG'; |
6822775c NC |
44 | # BM is eliminated post 5.9.5, but effectively is a specialisation of GV now. |
45 | @B::BM::ISA = $] > 5.009005 ? 'B::GV' : 'B::PVMG'; | |
a798dbf2 MB |
46 | @B::AV::ISA = 'B::PVMG'; |
47 | @B::GV::ISA = 'B::PVMG'; | |
48 | @B::HV::ISA = 'B::PVMG'; | |
49 | @B::CV::ISA = 'B::PVMG'; | |
276493cb SM |
50 | @B::IO::ISA = 'B::PVMG'; |
51 | @B::FM::ISA = 'B::CV'; | |
a798dbf2 MB |
52 | |
53 | @B::OP::ISA = 'B::OBJECT'; | |
54 | @B::UNOP::ISA = 'B::OP'; | |
55 | @B::BINOP::ISA = 'B::UNOP'; | |
56 | @B::LOGOP::ISA = 'B::UNOP'; | |
a798dbf2 MB |
57 | @B::LISTOP::ISA = 'B::BINOP'; |
58 | @B::SVOP::ISA = 'B::OP'; | |
7934575e | 59 | @B::PADOP::ISA = 'B::OP'; |
a798dbf2 | 60 | @B::PVOP::ISA = 'B::OP'; |
a798dbf2 MB |
61 | @B::LOOP::ISA = 'B::LISTOP'; |
62 | @B::PMOP::ISA = 'B::LISTOP'; | |
63 | @B::COP::ISA = 'B::OP'; | |
64 | ||
65 | @B::SPECIAL::ISA = 'B::OBJECT'; | |
66 | ||
baccf54f NC |
67 | @B::optype = qw(OP UNOP BINOP LOGOP LISTOP PMOP SVOP PADOP PVOP LOOP COP); |
68 | # bytecode.pl contained the following comment: | |
69 | # Nullsv *must* come first in the following so that the condition | |
70 | # ($$sv == 0) can continue to be used to test (sv == Nullsv). | |
71 | @B::specialsv_name = qw(Nullsv &PL_sv_undef &PL_sv_yes &PL_sv_no | |
72 | (SV*)pWARN_ALL (SV*)pWARN_NONE (SV*)pWARN_STD); | |
73 | ||
a798dbf2 MB |
74 | { |
75 | # Stop "-w" from complaining about the lack of a real B::OBJECT class | |
76 | package B::OBJECT; | |
77 | } | |
78 | ||
002b978b RH |
79 | sub B::GV::SAFENAME { |
80 | my $name = (shift())->NAME; | |
d9963e60 RH |
81 | |
82 | # The regex below corresponds to the isCONTROLVAR macro | |
83 | # from toke.c | |
84 | ||
7a9b44b9 RH |
85 | $name =~ s/^([\cA-\cZ\c\\c[\c]\c?\c_\c^])/"^". |
86 | chr( utf8::unicode_to_native( 64 ^ ord($1) ))/e; | |
87 | ||
88 | # When we say unicode_to_native we really mean ascii_to_native, | |
89 | # which matters iff this is a non-ASCII platform (EBCDIC). | |
90 | ||
002b978b RH |
91 | return $name; |
92 | } | |
93 | ||
d9963e60 RH |
94 | sub B::IV::int_value { |
95 | my ($self) = @_; | |
96 | return (($self->FLAGS() & SVf_IVisUV()) ? $self->UVX : $self->IV); | |
97 | } | |
98 | ||
f3402b25 RH |
99 | sub B::NULL::as_string() {""} |
100 | sub B::IV::as_string() {goto &B::IV::int_value} | |
101 | sub B::PV::as_string() {goto &B::PV::PV} | |
102 | ||
a798dbf2 MB |
103 | my $debug; |
104 | my $op_count = 0; | |
105 | my @parents = (); | |
106 | ||
107 | sub debug { | |
108 | my ($class, $value) = @_; | |
109 | $debug = $value; | |
110 | walkoptree_debug($value); | |
111 | } | |
112 | ||
a798dbf2 MB |
113 | sub class { |
114 | my $obj = shift; | |
115 | my $name = ref $obj; | |
116 | $name =~ s/^.*:://; | |
117 | return $name; | |
118 | } | |
119 | ||
120 | sub parents { \@parents } | |
121 | ||
122 | # For debugging | |
123 | sub peekop { | |
124 | my $op = shift; | |
3f872cb9 | 125 | return sprintf("%s (0x%x) %s", class($op), $$op, $op->name); |
a798dbf2 MB |
126 | } |
127 | ||
b2590c4e | 128 | sub walkoptree_slow { |
a798dbf2 MB |
129 | my($op, $method, $level) = @_; |
130 | $op_count++; # just for statistics | |
131 | $level ||= 0; | |
132 | warn(sprintf("walkoptree: %d. %s\n", $level, peekop($op))) if $debug; | |
156f89f0 | 133 | $op->$method($level) if $op->can($method); |
a798dbf2 MB |
134 | if ($$op && ($op->flags & OPf_KIDS)) { |
135 | my $kid; | |
136 | unshift(@parents, $op); | |
137 | for ($kid = $op->first; $$kid; $kid = $kid->sibling) { | |
b2590c4e | 138 | walkoptree_slow($kid, $method, $level + 1); |
a798dbf2 MB |
139 | } |
140 | shift @parents; | |
141 | } | |
156f89f0 JJ |
142 | if (class($op) eq 'PMOP' |
143 | && ref($op->pmreplroot) | |
144 | && ${$op->pmreplroot} | |
145 | && $op->pmreplroot->isa( 'B::OP' )) | |
146 | { | |
0091380b RGS |
147 | unshift(@parents, $op); |
148 | walkoptree_slow($op->pmreplroot, $method, $level + 1); | |
149 | shift @parents; | |
150 | } | |
a798dbf2 MB |
151 | } |
152 | ||
153 | sub compile_stats { | |
154 | return "Total number of OPs processed: $op_count\n"; | |
155 | } | |
156 | ||
157 | sub timing_info { | |
158 | my ($sec, $min, $hr) = localtime; | |
159 | my ($user, $sys) = times; | |
160 | sprintf("%02d:%02d:%02d user=$user sys=$sys", | |
161 | $hr, $min, $sec, $user, $sys); | |
162 | } | |
163 | ||
164 | my %symtable; | |
2b8dc4d2 DM |
165 | |
166 | sub clearsym { | |
167 | %symtable = (); | |
168 | } | |
169 | ||
a798dbf2 MB |
170 | sub savesym { |
171 | my ($obj, $value) = @_; | |
172 | # warn(sprintf("savesym: sym_%x => %s\n", $$obj, $value)); # debug | |
173 | $symtable{sprintf("sym_%x", $$obj)} = $value; | |
174 | } | |
175 | ||
176 | sub objsym { | |
177 | my $obj = shift; | |
178 | return $symtable{sprintf("sym_%x", $$obj)}; | |
179 | } | |
180 | ||
181 | sub walkoptree_exec { | |
182 | my ($op, $method, $level) = @_; | |
244826eb | 183 | $level ||= 0; |
a798dbf2 MB |
184 | my ($sym, $ppname); |
185 | my $prefix = " " x $level; | |
186 | for (; $$op; $op = $op->next) { | |
187 | $sym = objsym($op); | |
188 | if (defined($sym)) { | |
189 | print $prefix, "goto $sym\n"; | |
190 | return; | |
191 | } | |
192 | savesym($op, sprintf("%s (0x%lx)", class($op), $$op)); | |
193 | $op->$method($level); | |
3f872cb9 | 194 | $ppname = $op->name; |
1a67a97c | 195 | if ($ppname =~ |
62e36f8a | 196 | /^(d?or(assign)?|and(assign)?|mapwhile|grepwhile|entertry|range|cond_expr)$/) |
1a67a97c | 197 | { |
a798dbf2 MB |
198 | print $prefix, uc($1), " => {\n"; |
199 | walkoptree_exec($op->other, $method, $level + 1); | |
200 | print $prefix, "}\n"; | |
3f872cb9 | 201 | } elsif ($ppname eq "match" || $ppname eq "subst") { |
a798dbf2 MB |
202 | my $pmreplstart = $op->pmreplstart; |
203 | if ($$pmreplstart) { | |
204 | print $prefix, "PMREPLSTART => {\n"; | |
205 | walkoptree_exec($pmreplstart, $method, $level + 1); | |
206 | print $prefix, "}\n"; | |
207 | } | |
3f872cb9 | 208 | } elsif ($ppname eq "substcont") { |
a798dbf2 MB |
209 | print $prefix, "SUBSTCONT => {\n"; |
210 | walkoptree_exec($op->other->pmreplstart, $method, $level + 1); | |
211 | print $prefix, "}\n"; | |
212 | $op = $op->other; | |
3f872cb9 | 213 | } elsif ($ppname eq "enterloop") { |
a798dbf2 MB |
214 | print $prefix, "REDO => {\n"; |
215 | walkoptree_exec($op->redoop, $method, $level + 1); | |
216 | print $prefix, "}\n", $prefix, "NEXT => {\n"; | |
217 | walkoptree_exec($op->nextop, $method, $level + 1); | |
218 | print $prefix, "}\n", $prefix, "LAST => {\n"; | |
219 | walkoptree_exec($op->lastop, $method, $level + 1); | |
220 | print $prefix, "}\n"; | |
3f872cb9 | 221 | } elsif ($ppname eq "subst") { |
a798dbf2 MB |
222 | my $replstart = $op->pmreplstart; |
223 | if ($$replstart) { | |
224 | print $prefix, "SUBST => {\n"; | |
225 | walkoptree_exec($replstart, $method, $level + 1); | |
226 | print $prefix, "}\n"; | |
227 | } | |
228 | } | |
229 | } | |
230 | } | |
231 | ||
232 | sub walksymtable { | |
233 | my ($symref, $method, $recurse, $prefix) = @_; | |
234 | my $sym; | |
0cc1d052 | 235 | my $ref; |
b6b0fb7b MB |
236 | my $fullname; |
237 | no strict 'refs'; | |
0cc1d052 NIS |
238 | $prefix = '' unless defined $prefix; |
239 | while (($sym, $ref) = each %$symref) { | |
b6b0fb7b | 240 | $fullname = "*main::".$prefix.$sym; |
a798dbf2 MB |
241 | if ($sym =~ /::$/) { |
242 | $sym = $prefix . $sym; | |
7834d9fb | 243 | if (svref_2object(\*$sym)->NAME ne "main::" && $sym ne "<none>::" && &$recurse($sym)) { |
b6b0fb7b | 244 | walksymtable(\%$fullname, $method, $recurse, $sym); |
a798dbf2 MB |
245 | } |
246 | } else { | |
b6b0fb7b | 247 | svref_2object(\*$fullname)->$method(); |
a798dbf2 MB |
248 | } |
249 | } | |
250 | } | |
251 | ||
252 | { | |
253 | package B::Section; | |
254 | my $output_fh; | |
255 | my %sections; | |
85cf7f2e | 256 | |
a798dbf2 MB |
257 | sub new { |
258 | my ($class, $section, $symtable, $default) = @_; | |
259 | $output_fh ||= FileHandle->new_tmpfile; | |
260 | my $obj = bless [-1, $section, $symtable, $default], $class; | |
261 | $sections{$section} = $obj; | |
262 | return $obj; | |
263 | } | |
85cf7f2e | 264 | |
a798dbf2 MB |
265 | sub get { |
266 | my ($class, $section) = @_; | |
267 | return $sections{$section}; | |
268 | } | |
269 | ||
270 | sub add { | |
271 | my $section = shift; | |
272 | while (defined($_ = shift)) { | |
273 | print $output_fh "$section->[1]\t$_\n"; | |
274 | $section->[0]++; | |
275 | } | |
276 | } | |
277 | ||
278 | sub index { | |
279 | my $section = shift; | |
280 | return $section->[0]; | |
281 | } | |
282 | ||
283 | sub name { | |
284 | my $section = shift; | |
285 | return $section->[1]; | |
286 | } | |
287 | ||
288 | sub symtable { | |
289 | my $section = shift; | |
290 | return $section->[2]; | |
291 | } | |
85cf7f2e | 292 | |
a798dbf2 MB |
293 | sub default { |
294 | my $section = shift; | |
295 | return $section->[3]; | |
296 | } | |
85cf7f2e | 297 | |
a798dbf2 MB |
298 | sub output { |
299 | my ($section, $fh, $format) = @_; | |
300 | my $name = $section->name; | |
301 | my $sym = $section->symtable || {}; | |
302 | my $default = $section->default; | |
303 | ||
304 | seek($output_fh, 0, 0); | |
305 | while (<$output_fh>) { | |
306 | chomp; | |
307 | s/^(.*?)\t//; | |
308 | if ($1 eq $name) { | |
309 | s{(s\\_[0-9a-f]+)} { | |
310 | exists($sym->{$1}) ? $sym->{$1} : $default; | |
311 | }ge; | |
312 | printf $fh $format, $_; | |
313 | } | |
314 | } | |
315 | } | |
316 | } | |
317 | ||
da4061d3 | 318 | XSLoader::load(); |
a798dbf2 MB |
319 | |
320 | 1; | |
7f20e9dd GS |
321 | |
322 | __END__ | |
323 | ||
324 | =head1 NAME | |
325 | ||
4b661dd3 | 326 | B - The Perl Compiler Backend |
7f20e9dd GS |
327 | |
328 | =head1 SYNOPSIS | |
329 | ||
330 | use B; | |
331 | ||
332 | =head1 DESCRIPTION | |
333 | ||
1a52ab62 MB |
334 | The C<B> module supplies classes which allow a Perl program to delve |
335 | into its own innards. It is the module used to implement the | |
336 | "backends" of the Perl compiler. Usage of the compiler does not | |
337 | require knowledge of this module: see the F<O> module for the | |
338 | user-visible part. The C<B> module is of use to those who want to | |
339 | write new compiler backends. This documentation assumes that the | |
340 | reader knows a fair amount about perl's internals including such | |
341 | things as SVs, OPs and the internal symbol table and syntax tree | |
342 | of a program. | |
343 | ||
85cf7f2e MJD |
344 | =head1 OVERVIEW |
345 | ||
346 | The C<B> module contains a set of utility functions for querying the | |
347 | current state of the Perl interpreter; typically these functions | |
348 | return objects from the B::SV and B::OP classes, or their derived | |
349 | classes. These classes in turn define methods for querying the | |
350 | resulting objects about their own internal state. | |
351 | ||
352 | =head1 Utility Functions | |
353 | ||
354 | The C<B> module exports a variety of functions: some are simple | |
355 | utility functions, others provide a Perl program with a way to | |
356 | get an initial "handle" on an internal object. | |
357 | ||
358 | =head2 Functions Returning C<B::SV>, C<B::AV>, C<B::HV>, and C<B::CV> objects | |
359 | ||
3d036c2b | 360 | For descriptions of the class hierarchy of these objects and the |
85cf7f2e MJD |
361 | methods that can be called on them, see below, L<"OVERVIEW OF |
362 | CLASSES"> and L<"SV-RELATED CLASSES">. | |
363 | ||
364 | =over 4 | |
365 | ||
366 | =item sv_undef | |
367 | ||
368 | Returns the SV object corresponding to the C variable C<sv_undef>. | |
369 | ||
370 | =item sv_yes | |
371 | ||
372 | Returns the SV object corresponding to the C variable C<sv_yes>. | |
373 | ||
374 | =item sv_no | |
375 | ||
376 | Returns the SV object corresponding to the C variable C<sv_no>. | |
377 | ||
378 | =item svref_2object(SVREF) | |
379 | ||
380 | Takes a reference to any Perl value, and turns the referred-to value | |
381 | into an object in the appropriate B::OP-derived or B::SV-derived | |
382 | class. Apart from functions such as C<main_root>, this is the primary | |
383 | way to get an initial "handle" on an internal perl data structure | |
384 | which can then be followed with the other access methods. | |
385 | ||
f31c3107 SM |
386 | The returned object will only be valid as long as the underlying OPs |
387 | and SVs continue to exist. Do not attempt to use the object after the | |
388 | underlying structures are freed. | |
389 | ||
85cf7f2e MJD |
390 | =item amagic_generation |
391 | ||
392 | Returns the SV object corresponding to the C variable C<amagic_generation>. | |
393 | ||
e13efe3c | 394 | =item init_av |
85cf7f2e MJD |
395 | |
396 | Returns the AV object (i.e. in class B::AV) representing INIT blocks. | |
397 | ||
ece599bd RGS |
398 | =item check_av |
399 | ||
400 | Returns the AV object (i.e. in class B::AV) representing CHECK blocks. | |
401 | ||
676456c2 AG |
402 | =item unitcheck_av |
403 | ||
404 | Returns the AV object (i.e. in class B::AV) representing UNITCHECK blocks. | |
405 | ||
85cf7f2e MJD |
406 | =item begin_av |
407 | ||
408 | Returns the AV object (i.e. in class B::AV) representing BEGIN blocks. | |
409 | ||
410 | =item end_av | |
411 | ||
412 | Returns the AV object (i.e. in class B::AV) representing END blocks. | |
413 | ||
414 | =item comppadlist | |
415 | ||
416 | Returns the AV object (i.e. in class B::AV) of the global comppadlist. | |
417 | ||
418 | =item regex_padav | |
419 | ||
420 | Only when perl was compiled with ithreads. | |
421 | ||
e13efe3c | 422 | =item main_cv |
85cf7f2e MJD |
423 | |
424 | Return the (faked) CV corresponding to the main part of the Perl | |
425 | program. | |
426 | ||
427 | =back | |
428 | ||
429 | =head2 Functions for Examining the Symbol Table | |
430 | ||
431 | =over 4 | |
432 | ||
433 | =item walksymtable(SYMREF, METHOD, RECURSE, PREFIX) | |
434 | ||
435 | Walk the symbol table starting at SYMREF and call METHOD on each | |
436 | symbol (a B::GV object) visited. When the walk reaches package | |
437 | symbols (such as "Foo::") it invokes RECURSE, passing in the symbol | |
438 | name, and only recurses into the package if that sub returns true. | |
439 | ||
440 | PREFIX is the name of the SYMREF you're walking. | |
441 | ||
442 | For example: | |
443 | ||
444 | # Walk CGI's symbol table calling print_subs on each symbol. | |
445 | # Recurse only into CGI::Util:: | |
446 | walksymtable(\%CGI::, 'print_subs', sub { $_[0] eq 'CGI::Util::' }, | |
447 | 'CGI::'); | |
448 | ||
449 | print_subs() is a B::GV method you have declared. Also see L<"B::GV | |
450 | Methods">, below. | |
451 | ||
452 | =back | |
453 | ||
454 | =head2 Functions Returning C<B::OP> objects or for walking op trees | |
455 | ||
3d036c2b | 456 | For descriptions of the class hierarchy of these objects and the |
85cf7f2e MJD |
457 | methods that can be called on them, see below, L<"OVERVIEW OF |
458 | CLASSES"> and L<"OP-RELATED CLASSES">. | |
459 | ||
460 | =over 4 | |
461 | ||
462 | =item main_root | |
463 | ||
464 | Returns the root op (i.e. an object in the appropriate B::OP-derived | |
465 | class) of the main part of the Perl program. | |
466 | ||
467 | =item main_start | |
468 | ||
469 | Returns the starting op of the main part of the Perl program. | |
470 | ||
471 | =item walkoptree(OP, METHOD) | |
472 | ||
473 | Does a tree-walk of the syntax tree based at OP and calls METHOD on | |
474 | each op it visits. Each node is visited before its children. If | |
475 | C<walkoptree_debug> (see below) has been called to turn debugging on then | |
476 | the method C<walkoptree_debug> is called on each op before METHOD is | |
477 | called. | |
478 | ||
479 | =item walkoptree_debug(DEBUG) | |
480 | ||
481 | Returns the current debugging flag for C<walkoptree>. If the optional | |
482 | DEBUG argument is non-zero, it sets the debugging flag to that. See | |
483 | the description of C<walkoptree> above for what the debugging flag | |
484 | does. | |
485 | ||
486 | =back | |
487 | ||
488 | =head2 Miscellaneous Utility Functions | |
489 | ||
490 | =over 4 | |
491 | ||
492 | =item ppname(OPNUM) | |
493 | ||
494 | Return the PP function name (e.g. "pp_add") of op number OPNUM. | |
495 | ||
496 | =item hash(STR) | |
497 | ||
498 | Returns a string in the form "0x..." representing the value of the | |
499 | internal hash function used by perl on string STR. | |
500 | ||
501 | =item cast_I32(I) | |
502 | ||
503 | Casts I to the internal I32 type used by that perl. | |
504 | ||
505 | =item minus_c | |
506 | ||
507 | Does the equivalent of the C<-c> command-line option. Obviously, this | |
508 | is only useful in a BEGIN block or else the flag is set too late. | |
509 | ||
510 | =item cstring(STR) | |
511 | ||
512 | Returns a double-quote-surrounded escaped version of STR which can | |
513 | be used as a string in C source code. | |
514 | ||
515 | =item perlstring(STR) | |
516 | ||
517 | Returns a double-quote-surrounded escaped version of STR which can | |
518 | be used as a string in Perl source code. | |
519 | ||
520 | =item class(OBJ) | |
521 | ||
522 | Returns the class of an object without the part of the classname | |
523 | preceding the first C<"::">. This is used to turn C<"B::UNOP"> into | |
524 | C<"UNOP"> for example. | |
525 | ||
526 | =item threadsv_names | |
527 | ||
528 | In a perl compiled for threads, this returns a list of the special | |
529 | per-thread threadsv variables. | |
530 | ||
531 | =back | |
532 | ||
baccf54f NC |
533 | =head2 Exported utility variabiles |
534 | ||
535 | =over 4 | |
536 | ||
537 | =item @optype | |
538 | ||
539 | my $op_type = $optype[$op_type_num]; | |
85cf7f2e | 540 | |
baccf54f NC |
541 | A simple mapping of the op type number to its type (like 'COP' or 'BINOP'). |
542 | ||
543 | =item @specialsv_name | |
544 | ||
545 | my $sv_name = $specialsv_name[$sv_index]; | |
546 | ||
547 | Certain SV types are considered 'special'. They're represented by | |
548 | B::SPECIAL and are referred to by a number from the specialsv_list. | |
549 | This array maps that number back to the name of the SV (like 'Nullsv' | |
550 | or '&PL_sv_undef'). | |
551 | ||
552 | =back | |
85cf7f2e MJD |
553 | |
554 | ||
1a52ab62 MB |
555 | =head1 OVERVIEW OF CLASSES |
556 | ||
557 | The C structures used by Perl's internals to hold SV and OP | |
558 | information (PVIV, AV, HV, ..., OP, SVOP, UNOP, ...) are modelled on a | |
559 | class hierarchy and the C<B> module gives access to them via a true | |
560 | object hierarchy. Structure fields which point to other objects | |
561 | (whether types of SV or types of OP) are represented by the C<B> | |
85cf7f2e MJD |
562 | module as Perl objects of the appropriate class. |
563 | ||
564 | The bulk of the C<B> module is the methods for accessing fields of | |
565 | these structures. | |
566 | ||
567 | Note that all access is read-only. You cannot modify the internals by | |
f31c3107 SM |
568 | using this module. Also, note that the B::OP and B::SV objects created |
569 | by this module are only valid for as long as the underlying objects | |
570 | exist; their creation doesn't increase the reference counts of the | |
571 | underlying objects. Trying to access the fields of a freed object will | |
572 | give incomprehensible results, or worse. | |
1a52ab62 MB |
573 | |
574 | =head2 SV-RELATED CLASSES | |
575 | ||
6822775c NC |
576 | B::IV, B::NV, B::RV, B::PV, B::PVIV, B::PVNV, B::PVMG, B::BM (5.9.5 and |
577 | earlier), B::PVLV, B::AV, B::HV, B::CV, B::GV, B::FM, B::IO. These classes | |
578 | correspond in the obvious way to the underlying C structures of similar names. | |
4df7f6af | 579 | The inheritance hierarchy mimics the underlying C "inheritance". For the |
dda36756 | 580 | 5.10.x branch, (I<ie> 5.10.0, 5.10.1 I<etc>) this is: |
85cf7f2e | 581 | |
6822775c NC |
582 | B::SV |
583 | | | |
584 | +------------+------------+------------+ | |
585 | | | | | | |
586 | B::PV B::IV B::NV B::RV | |
587 | \ / / | |
588 | \ / / | |
589 | B::PVIV / | |
b591c46e NC |
590 | \ / |
591 | \ / | |
592 | \ / | |
593 | B::PVNV | |
594 | | | |
595 | | | |
596 | B::PVMG | |
597 | | | |
6822775c NC |
598 | +-----+-----+-----+-----+ |
599 | | | | | | | |
600 | B::AV B::GV B::HV B::CV B::IO | |
601 | | | | |
602 | | | | |
603 | B::PVLV B::FM | |
604 | ||
6822775c NC |
605 | For 5.9.0 and earlier, PVLV is a direct subclass of PVMG, and BM is still |
606 | present as a distinct type, so the base of this diagram is | |
607 | ||
608 | ||
609 | | | |
610 | | | |
611 | B::PVMG | |
612 | | | |
613 | +------+-----+-----+-----+-----+-----+ | |
614 | | | | | | | | | |
615 | B::PVLV B::BM B::AV B::GV B::HV B::CV B::IO | |
616 | | | |
617 | | | |
618 | B::FM | |
f5ba1307 | 619 | |
dda36756 NC |
620 | For 5.11.0 and later, B::RV is abolished, and IVs can be used to store |
621 | references, and a new type B::REGEXP is introduced, giving this structure: | |
622 | ||
623 | B::SV | |
624 | | | |
625 | +------------+------------+ | |
626 | | | | | |
627 | B::PV B::IV B::NV | |
628 | \ / / | |
629 | \ / / | |
630 | B::PVIV / | |
631 | \ / | |
632 | \ / | |
633 | \ / | |
634 | B::PVNV | |
635 | | | |
636 | | | |
637 | B::PVMG | |
638 | | | |
639 | +-------+-------+---+---+-------+-------+ | |
640 | | | | | | | | |
641 | B::AV B::GV B::HV B::CV B::IO B::REGEXP | |
642 | | | | |
643 | | | | |
644 | B::PVLV B::FM | |
645 | ||
f5ba1307 | 646 | |
85cf7f2e | 647 | Access methods correspond to the underlying C macros for field access, |
1a52ab62 MB |
648 | usually with the leading "class indication" prefix removed (Sv, Av, |
649 | Hv, ...). The leading prefix is only left in cases where its removal | |
650 | would cause a clash in method name. For example, C<GvREFCNT> stays | |
651 | as-is since its abbreviation would clash with the "superclass" method | |
652 | C<REFCNT> (corresponding to the C function C<SvREFCNT>). | |
653 | ||
85cf7f2e | 654 | =head2 B::SV Methods |
1a52ab62 MB |
655 | |
656 | =over 4 | |
657 | ||
658 | =item REFCNT | |
659 | ||
660 | =item FLAGS | |
661 | ||
429a5ce7 SM |
662 | =item object_2svref |
663 | ||
664 | Returns a reference to the regular scalar corresponding to this | |
665 | B::SV object. In other words, this method is the inverse operation | |
666 | to the svref_2object() subroutine. This scalar and other data it points | |
667 | at should be considered read-only: modifying them is neither safe nor | |
668 | guaranteed to have a sensible effect. | |
669 | ||
1a52ab62 MB |
670 | =back |
671 | ||
85cf7f2e | 672 | =head2 B::IV Methods |
1a52ab62 MB |
673 | |
674 | =over 4 | |
675 | ||
676 | =item IV | |
677 | ||
d9963e60 RH |
678 | Returns the value of the IV, I<interpreted as |
679 | a signed integer>. This will be misleading | |
680 | if C<FLAGS & SVf_IVisUV>. Perhaps you want the | |
681 | C<int_value> method instead? | |
682 | ||
1a52ab62 MB |
683 | =item IVX |
684 | ||
d9963e60 RH |
685 | =item UVX |
686 | ||
687 | =item int_value | |
688 | ||
689 | This method returns the value of the IV as an integer. | |
690 | It differs from C<IV> in that it returns the correct | |
691 | value regardless of whether it's stored signed or | |
692 | unsigned. | |
693 | ||
1a52ab62 MB |
694 | =item needs64bits |
695 | ||
696 | =item packiv | |
697 | ||
698 | =back | |
699 | ||
85cf7f2e | 700 | =head2 B::NV Methods |
1a52ab62 MB |
701 | |
702 | =over 4 | |
703 | ||
704 | =item NV | |
705 | ||
706 | =item NVX | |
707 | ||
708 | =back | |
709 | ||
85cf7f2e | 710 | =head2 B::RV Methods |
1a52ab62 MB |
711 | |
712 | =over 4 | |
713 | ||
714 | =item RV | |
715 | ||
716 | =back | |
717 | ||
85cf7f2e | 718 | =head2 B::PV Methods |
1a52ab62 MB |
719 | |
720 | =over 4 | |
721 | ||
722 | =item PV | |
723 | ||
76ef7183 JH |
724 | This method is the one you usually want. It constructs a |
725 | string using the length and offset information in the struct: | |
726 | for ordinary scalars it will return the string that you'd see | |
727 | from Perl, even if it contains null characters. | |
728 | ||
9d2bbe64 MB |
729 | =item RV |
730 | ||
731 | Same as B::RV::RV, except that it will die() if the PV isn't | |
732 | a reference. | |
733 | ||
0b40bd6d RH |
734 | =item PVX |
735 | ||
76ef7183 JH |
736 | This method is less often useful. It assumes that the string |
737 | stored in the struct is null-terminated, and disregards the | |
738 | length information. | |
739 | ||
740 | It is the appropriate method to use if you need to get the name | |
741 | of a lexical variable from a padname array. Lexical variable names | |
742 | are always stored with a null terminator, and the length field | |
743 | (SvCUR) is overloaded for other purposes and can't be relied on here. | |
744 | ||
1a52ab62 MB |
745 | =back |
746 | ||
85cf7f2e | 747 | =head2 B::PVMG Methods |
1a52ab62 MB |
748 | |
749 | =over 4 | |
750 | ||
751 | =item MAGIC | |
752 | ||
753 | =item SvSTASH | |
754 | ||
755 | =back | |
756 | ||
85cf7f2e | 757 | =head2 B::MAGIC Methods |
1a52ab62 MB |
758 | |
759 | =over 4 | |
760 | ||
761 | =item MOREMAGIC | |
762 | ||
9d2bbe64 MB |
763 | =item precomp |
764 | ||
765 | Only valid on r-magic, returns the string that generated the regexp. | |
766 | ||
1a52ab62 MB |
767 | =item PRIVATE |
768 | ||
769 | =item TYPE | |
770 | ||
771 | =item FLAGS | |
772 | ||
773 | =item OBJ | |
774 | ||
9d2bbe64 MB |
775 | Will die() if called on r-magic. |
776 | ||
1a52ab62 MB |
777 | =item PTR |
778 | ||
9d2bbe64 MB |
779 | =item REGEX |
780 | ||
781 | Only valid on r-magic, returns the integer value of the REGEX stored | |
782 | in the MAGIC. | |
783 | ||
1a52ab62 MB |
784 | =back |
785 | ||
85cf7f2e | 786 | =head2 B::PVLV Methods |
1a52ab62 MB |
787 | |
788 | =over 4 | |
789 | ||
790 | =item TARGOFF | |
791 | ||
792 | =item TARGLEN | |
793 | ||
794 | =item TYPE | |
795 | ||
796 | =item TARG | |
797 | ||
798 | =back | |
799 | ||
85cf7f2e | 800 | =head2 B::BM Methods |
1a52ab62 MB |
801 | |
802 | =over 4 | |
803 | ||
804 | =item USEFUL | |
805 | ||
806 | =item PREVIOUS | |
807 | ||
808 | =item RARE | |
809 | ||
810 | =item TABLE | |
811 | ||
812 | =back | |
813 | ||
85cf7f2e | 814 | =head2 B::GV Methods |
1a52ab62 MB |
815 | |
816 | =over 4 | |
817 | ||
87d7fd28 GS |
818 | =item is_empty |
819 | ||
820 | This method returns TRUE if the GP field of the GV is NULL. | |
821 | ||
1a52ab62 MB |
822 | =item NAME |
823 | ||
002b978b RH |
824 | =item SAFENAME |
825 | ||
826 | This method returns the name of the glob, but if the first | |
827 | character of the name is a control character, then it converts | |
828 | it to ^X first, so that *^G would return "^G" rather than "\cG". | |
829 | ||
830 | It's useful if you want to print out the name of a variable. | |
831 | If you restrict yourself to globs which exist at compile-time | |
832 | then the result ought to be unambiguous, because code like | |
833 | C<${"^G"} = 1> is compiled as two ops - a constant string and | |
834 | a dereference (rv2gv) - so that the glob is created at runtime. | |
835 | ||
836 | If you're working with globs at runtime, and need to disambiguate | |
837 | *^G from *{"^G"}, then you should use the raw NAME method. | |
838 | ||
1a52ab62 MB |
839 | =item STASH |
840 | ||
841 | =item SV | |
842 | ||
843 | =item IO | |
844 | ||
845 | =item FORM | |
846 | ||
847 | =item AV | |
848 | ||
849 | =item HV | |
850 | ||
851 | =item EGV | |
852 | ||
853 | =item CV | |
854 | ||
855 | =item CVGEN | |
856 | ||
857 | =item LINE | |
858 | ||
b195d487 GS |
859 | =item FILE |
860 | ||
1a52ab62 MB |
861 | =item FILEGV |
862 | ||
863 | =item GvREFCNT | |
864 | ||
865 | =item FLAGS | |
866 | ||
867 | =back | |
868 | ||
85cf7f2e | 869 | =head2 B::IO Methods |
1a52ab62 MB |
870 | |
871 | =over 4 | |
872 | ||
873 | =item LINES | |
874 | ||
875 | =item PAGE | |
876 | ||
877 | =item PAGE_LEN | |
878 | ||
879 | =item LINES_LEFT | |
880 | ||
881 | =item TOP_NAME | |
882 | ||
883 | =item TOP_GV | |
884 | ||
885 | =item FMT_NAME | |
886 | ||
887 | =item FMT_GV | |
888 | ||
889 | =item BOTTOM_NAME | |
890 | ||
891 | =item BOTTOM_GV | |
892 | ||
893 | =item SUBPROCESS | |
894 | ||
895 | =item IoTYPE | |
896 | ||
897 | =item IoFLAGS | |
898 | ||
9d2bbe64 MB |
899 | =item IsSTD |
900 | ||
901 | Takes one arguments ( 'stdin' | 'stdout' | 'stderr' ) and returns true | |
902 | if the IoIFP of the object is equal to the handle whose name was | |
903 | passed as argument ( i.e. $io->IsSTD('stderr') is true if | |
904 | IoIFP($io) == PerlIO_stdin() ). | |
905 | ||
1a52ab62 MB |
906 | =back |
907 | ||
85cf7f2e | 908 | =head2 B::AV Methods |
1a52ab62 MB |
909 | |
910 | =over 4 | |
911 | ||
912 | =item FILL | |
913 | ||
914 | =item MAX | |
915 | ||
1a52ab62 MB |
916 | =item ARRAY |
917 | ||
429a5ce7 SM |
918 | =item ARRAYelt |
919 | ||
920 | Like C<ARRAY>, but takes an index as an argument to get only one element, | |
921 | rather than a list of all of them. | |
922 | ||
edcc7c74 NC |
923 | =item OFF |
924 | ||
925 | This method is deprecated if running under Perl 5.8, and is no longer present | |
926 | if running under Perl 5.9 | |
927 | ||
928 | =item AvFLAGS | |
929 | ||
930 | This method returns the AV specific flags. In Perl 5.9 these are now stored | |
931 | in with the main SV flags, so this method is no longer present. | |
932 | ||
1a52ab62 MB |
933 | =back |
934 | ||
85cf7f2e | 935 | =head2 B::CV Methods |
1a52ab62 MB |
936 | |
937 | =over 4 | |
938 | ||
939 | =item STASH | |
940 | ||
941 | =item START | |
942 | ||
943 | =item ROOT | |
944 | ||
945 | =item GV | |
946 | ||
57843af0 GS |
947 | =item FILE |
948 | ||
1a52ab62 MB |
949 | =item DEPTH |
950 | ||
951 | =item PADLIST | |
952 | ||
953 | =item OUTSIDE | |
954 | ||
a3985cdc DM |
955 | =item OUTSIDE_SEQ |
956 | ||
1a52ab62 MB |
957 | =item XSUB |
958 | ||
959 | =item XSUBANY | |
960 | ||
9d2bbe64 MB |
961 | For constant subroutines, returns the constant SV returned by the subroutine. |
962 | ||
5cfd8ad4 VB |
963 | =item CvFLAGS |
964 | ||
de3f1649 JT |
965 | =item const_sv |
966 | ||
1a52ab62 MB |
967 | =back |
968 | ||
85cf7f2e | 969 | =head2 B::HV Methods |
1a52ab62 MB |
970 | |
971 | =over 4 | |
972 | ||
973 | =item FILL | |
974 | ||
975 | =item MAX | |
976 | ||
977 | =item KEYS | |
978 | ||
979 | =item RITER | |
980 | ||
981 | =item NAME | |
982 | ||
1a52ab62 MB |
983 | =item ARRAY |
984 | ||
edcc7c74 NC |
985 | =item PMROOT |
986 | ||
987 | This method is not present if running under Perl 5.9, as the PMROOT | |
988 | information is no longer stored directly in the hash. | |
989 | ||
1a52ab62 MB |
990 | =back |
991 | ||
992 | =head2 OP-RELATED CLASSES | |
993 | ||
85cf7f2e | 994 | C<B::OP>, C<B::UNOP>, C<B::BINOP>, C<B::LOGOP>, C<B::LISTOP>, C<B::PMOP>, |
651aa52e | 995 | C<B::SVOP>, C<B::PADOP>, C<B::PVOP>, C<B::LOOP>, C<B::COP>. |
85cf7f2e MJD |
996 | |
997 | These classes correspond in the obvious way to the underlying C | |
998 | structures of similar names. The inheritance hierarchy mimics the | |
999 | underlying C "inheritance": | |
1000 | ||
1001 | B::OP | |
1002 | | | |
5ce57cc0 JJ |
1003 | +---------------+--------+--------+-------+ |
1004 | | | | | | | |
1005 | B::UNOP B::SVOP B::PADOP B::COP B::PVOP | |
85cf7f2e MJD |
1006 | ,' `-. |
1007 | / `--. | |
1008 | B::BINOP B::LOGOP | |
1009 | | | |
1010 | | | |
1011 | B::LISTOP | |
1012 | ,' `. | |
1013 | / \ | |
1014 | B::LOOP B::PMOP | |
1015 | ||
1016 | Access methods correspond to the underlying C structre field names, | |
1017 | with the leading "class indication" prefix (C<"op_">) removed. | |
1018 | ||
1019 | =head2 B::OP Methods | |
1a52ab62 | 1020 | |
a60ba18b JC |
1021 | These methods get the values of similarly named fields within the OP |
1022 | data structure. See top of C<op.h> for more info. | |
1023 | ||
1a52ab62 MB |
1024 | =over 4 |
1025 | ||
1026 | =item next | |
1027 | ||
1028 | =item sibling | |
1029 | ||
3f872cb9 GS |
1030 | =item name |
1031 | ||
1032 | This returns the op name as a string (e.g. "add", "rv2av"). | |
1033 | ||
1a52ab62 MB |
1034 | =item ppaddr |
1035 | ||
dc333d64 GS |
1036 | This returns the function name as a string (e.g. "PL_ppaddr[OP_ADD]", |
1037 | "PL_ppaddr[OP_RV2AV]"). | |
1a52ab62 MB |
1038 | |
1039 | =item desc | |
1040 | ||
4369b173 | 1041 | This returns the op description from the global C PL_op_desc array |
1a52ab62 MB |
1042 | (e.g. "addition" "array deref"). |
1043 | ||
1044 | =item targ | |
1045 | ||
1046 | =item type | |
1047 | ||
a60ba18b JC |
1048 | =item opt |
1049 | ||
1a52ab62 MB |
1050 | =item flags |
1051 | ||
1052 | =item private | |
1053 | ||
a60ba18b JC |
1054 | =item spare |
1055 | ||
1a52ab62 MB |
1056 | =back |
1057 | ||
1058 | =head2 B::UNOP METHOD | |
1059 | ||
1060 | =over 4 | |
1061 | ||
1062 | =item first | |
1063 | ||
1064 | =back | |
1065 | ||
1066 | =head2 B::BINOP METHOD | |
1067 | ||
1068 | =over 4 | |
1069 | ||
1070 | =item last | |
1071 | ||
1072 | =back | |
1073 | ||
1074 | =head2 B::LOGOP METHOD | |
1075 | ||
1076 | =over 4 | |
1077 | ||
1078 | =item other | |
1079 | ||
1080 | =back | |
1081 | ||
1a52ab62 MB |
1082 | =head2 B::LISTOP METHOD |
1083 | ||
1084 | =over 4 | |
1085 | ||
1086 | =item children | |
1087 | ||
1088 | =back | |
1089 | ||
85cf7f2e | 1090 | =head2 B::PMOP Methods |
1a52ab62 MB |
1091 | |
1092 | =over 4 | |
1093 | ||
1094 | =item pmreplroot | |
1095 | ||
1096 | =item pmreplstart | |
1097 | ||
1098 | =item pmnext | |
1099 | ||
196d796c RU |
1100 | Only up to Perl 5.9.4 |
1101 | ||
1a52ab62 MB |
1102 | =item pmflags |
1103 | ||
c737faaf | 1104 | =item extflags |
1a52ab62 | 1105 | |
196d796c RU |
1106 | Since Perl 5.9.5 |
1107 | ||
1a52ab62 MB |
1108 | =item precomp |
1109 | ||
651aa52e | 1110 | =item pmoffset |
9d2bbe64 MB |
1111 | |
1112 | Only when perl was compiled with ithreads. | |
1113 | ||
1a52ab62 MB |
1114 | =back |
1115 | ||
1116 | =head2 B::SVOP METHOD | |
1117 | ||
1118 | =over 4 | |
1119 | ||
1120 | =item sv | |
1121 | ||
065a1863 GS |
1122 | =item gv |
1123 | ||
1a52ab62 MB |
1124 | =back |
1125 | ||
7934575e | 1126 | =head2 B::PADOP METHOD |
1a52ab62 MB |
1127 | |
1128 | =over 4 | |
1129 | ||
7934575e | 1130 | =item padix |
1a52ab62 MB |
1131 | |
1132 | =back | |
1133 | ||
1134 | =head2 B::PVOP METHOD | |
1135 | ||
1136 | =over 4 | |
1137 | ||
1138 | =item pv | |
1139 | ||
1140 | =back | |
1141 | ||
85cf7f2e | 1142 | =head2 B::LOOP Methods |
1a52ab62 MB |
1143 | |
1144 | =over 4 | |
1145 | ||
1146 | =item redoop | |
1147 | ||
1148 | =item nextop | |
1149 | ||
1150 | =item lastop | |
1151 | ||
1152 | =back | |
1153 | ||
85cf7f2e | 1154 | =head2 B::COP Methods |
1a52ab62 MB |
1155 | |
1156 | =over 4 | |
1157 | ||
1158 | =item label | |
1159 | ||
1160 | =item stash | |
1161 | ||
6e6a1aef RGS |
1162 | =item stashpv |
1163 | ||
57843af0 | 1164 | =item file |
1a52ab62 MB |
1165 | |
1166 | =item cop_seq | |
1167 | ||
1168 | =item arybase | |
1169 | ||
1170 | =item line | |
1171 | ||
6e6a1aef RGS |
1172 | =item warnings |
1173 | ||
1174 | =item io | |
1175 | ||
d5ec2987 NC |
1176 | =item hints |
1177 | ||
b47e7f93 RGS |
1178 | =item hints_hash |
1179 | ||
1a52ab62 MB |
1180 | =back |
1181 | ||
7f20e9dd GS |
1182 | |
1183 | =head1 AUTHOR | |
1184 | ||
1185 | Malcolm Beattie, C<mbeattie@sable.ox.ac.uk> | |
1186 | ||
1187 | =cut |