# License or the Artistic License, as specified in the README file.
#
package B;
+use strict;
-our $VERSION = '1.19';
-
-use XSLoader ();
require Exporter;
-@ISA = qw(Exporter);
+@B::ISA = qw(Exporter);
# walkoptree_slow comes from B.pm (you are there),
# walkoptree comes from B.xs
-@EXPORT_OK = qw(minus_c ppname save_BEGINs
- class peekop cast_I32 cstring cchar hash threadsv_names
- main_root main_start main_cv svref_2object opnumber
- sub_generation amagic_generation perlstring
- walkoptree_slow walkoptree walkoptree_exec walksymtable
- parents comppadlist sv_undef compile_stats timing_info
- begin_av init_av check_av end_av regex_padav dowarn defstash
- curstash warnhook diehook inc_gv @optype @specialsv_name
- );
-push @EXPORT_OK, qw(unitcheck_av) if $] > 5.009;
-
-sub OPf_KIDS ();
-use strict;
+
+BEGIN {
+ $B::VERSION = '1.43';
+ @B::EXPORT_OK = ();
+
+ # Our BOOT code needs $VERSION set, and will append to @EXPORT_OK.
+ # Want our constants loaded before the compiler meets OPf_KIDS below, as
+ # the combination of having the constant stay a Proxy Constant Subroutine
+ # and its value being inlined saves a little over .5K
+
+ require XSLoader;
+ XSLoader::load();
+}
+
+push @B::EXPORT_OK, (qw(minus_c ppname save_BEGINs
+ class peekop cast_I32 cstring cchar hash threadsv_names
+ main_root main_start main_cv svref_2object opnumber
+ sub_generation amagic_generation perlstring
+ walkoptree_slow walkoptree walkoptree_exec walksymtable
+ parents comppadlist sv_undef compile_stats timing_info
+ begin_av init_av check_av end_av regex_padav dowarn
+ defstash curstash warnhook diehook inc_gv @optype
+ @specialsv_name unitcheck_av));
+
@B::SV::ISA = 'B::OBJECT';
@B::NULL::ISA = 'B::SV';
@B::PV::ISA = 'B::SV';
@B::PVNV::ISA = qw(B::PVIV B::NV);
@B::PVMG::ISA = 'B::PVNV';
@B::REGEXP::ISA = 'B::PVMG' if $] >= 5.011;
-# Change in the inheritance hierarchy post 5.9.0
-@B::PVLV::ISA = $] > 5.009 ? 'B::GV' : 'B::PVMG';
-# BM is eliminated post 5.9.5, but effectively is a specialisation of GV now.
-@B::BM::ISA = $] > 5.009005 ? 'B::GV' : 'B::PVMG';
+@B::PVLV::ISA = 'B::GV';
+@B::BM::ISA = 'B::GV';
@B::AV::ISA = 'B::PVMG';
@B::GV::ISA = 'B::PVMG';
@B::HV::ISA = 'B::PVMG';
}
sub B::NULL::as_string() {""}
-sub B::IV::as_string() {goto &B::IV::int_value}
-sub B::PV::as_string() {goto &B::PV::PV}
+*B::IV::as_string = \*B::IV::int_value;
+*B::PV::as_string = \*B::PV::PV;
+
+# The input typemap checking makes no distinction between different SV types,
+# so the XS body will generate the same C code, despite the different XS
+# "types". So there is no change in behaviour from doing "newXS" like this,
+# compared with the old approach of having a (near) duplicate XS body.
+# We should fix the typemap checking.
+*B::IV::RV = \*B::PV::RV if $] > 5.012;
my $debug;
my $op_count = 0;
my $fullname;
no strict 'refs';
$prefix = '' unless defined $prefix;
- while (($sym, $ref) = each %$symref) {
+ foreach my $sym ( sort keys %$symref ) {
+ $ref= $symref->{$sym};
$fullname = "*main::".$prefix.$sym;
if ($sym =~ /::$/) {
$sym = $prefix . $sym;
- if ($sym ne "main::" && $sym ne "<none>::" && &$recurse($sym)) {
+ if (svref_2object(\*$sym)->NAME ne "main::" && $sym ne "<none>::" && &$recurse($sym)) {
walksymtable(\%$fullname, $method, $recurse, $sym);
}
} else {
}
}
-XSLoader::load 'B';
-
1;
__END__
=head1 NAME
-B - The Perl Compiler
+B - The Perl Compiler Backend
=head1 SYNOPSIS
=head1 DESCRIPTION
The C<B> module supplies classes which allow a Perl program to delve
-into its own innards. It is the module used to implement the
-"backends" of the Perl compiler. Usage of the compiler does not
+into its own innards. It is the module used to implement the
+"backends" of the Perl compiler. Usage of the compiler does not
require knowledge of this module: see the F<O> module for the
-user-visible part. The C<B> module is of use to those who want to
-write new compiler backends. This documentation assumes that the
+user-visible part. The C<B> module is of use to those who want to
+write new compiler backends. This documentation assumes that the
reader knows a fair amount about perl's internals including such
things as SVs, OPs and the internal symbol table and syntax tree
of a program.
Takes a reference to any Perl value, and turns the referred-to value
into an object in the appropriate B::OP-derived or B::SV-derived
-class. Apart from functions such as C<main_root>, this is the primary
+class. Apart from functions such as C<main_root>, this is the primary
way to get an initial "handle" on an internal perl data structure
which can then be followed with the other access methods.
The returned object will only be valid as long as the underlying OPs
-and SVs continue to exist. Do not attempt to use the object after the
+and SVs continue to exist. Do not attempt to use the object after the
underlying structures are freed.
=item amagic_generation
Returns the SV object corresponding to the C variable C<amagic_generation>.
+As of Perl 5.18, this is just an alias to C<PL_na>, so its value is
+meaningless.
=item init_av
# Walk CGI's symbol table calling print_subs on each symbol.
# Recurse only into CGI::Util::
- walksymtable(\%CGI::, 'print_subs', sub { $_[0] eq 'CGI::Util::' },
- 'CGI::');
+ walksymtable(\%CGI::, 'print_subs',
+ sub { $_[0] eq 'CGI::Util::' }, 'CGI::');
-print_subs() is a B::GV method you have declared. Also see L<"B::GV
+print_subs() is a B::GV method you have declared. Also see L<"B::GV
Methods">, below.
=back
=item walkoptree(OP, METHOD)
Does a tree-walk of the syntax tree based at OP and calls METHOD on
-each op it visits. Each node is visited before its children. If
+each op it visits. Each node is visited before its children. If
C<walkoptree_debug> (see below) has been called to turn debugging on then
the method C<walkoptree_debug> is called on each op before METHOD is
called.
=item walkoptree_debug(DEBUG)
-Returns the current debugging flag for C<walkoptree>. If the optional
-DEBUG argument is non-zero, it sets the debugging flag to that. See
+Returns the current debugging flag for C<walkoptree>. If the optional
+DEBUG argument is non-zero, it sets the debugging flag to that. See
the description of C<walkoptree> above for what the debugging flag
does.
=item minus_c
-Does the equivalent of the C<-c> command-line option. Obviously, this
+Does the equivalent of the C<-c> command-line option. Obviously, this
is only useful in a BEGIN block or else the flag is set too late.
=item cstring(STR)
=item class(OBJ)
Returns the class of an object without the part of the classname
-preceding the first C<"::">. This is used to turn C<"B::UNOP"> into
+preceding the first C<"::">. This is used to turn C<"B::UNOP"> into
C<"UNOP"> for example.
=item threadsv_names
=back
-=head2 Exported utility variabiles
+=head2 Exported utility variables
=over 4
The C structures used by Perl's internals to hold SV and OP
information (PVIV, AV, HV, ..., OP, SVOP, UNOP, ...) are modelled on a
class hierarchy and the C<B> module gives access to them via a true
-object hierarchy. Structure fields which point to other objects
+object hierarchy. Structure fields which point to other objects
(whether types of SV or types of OP) are represented by the C<B>
module as Perl objects of the appropriate class.
these structures.
Note that all access is read-only. You cannot modify the internals by
-using this module. Also, note that the B::OP and B::SV objects created
+using this module. Also, note that the B::OP and B::SV objects created
by this module are only valid for as long as the underlying objects
exist; their creation doesn't increase the reference counts of the
-underlying objects. Trying to access the fields of a freed object will
+underlying objects. Trying to access the fields of a freed object will
give incomprehensible results, or worse.
=head2 SV-RELATED CLASSES
B::IV, B::NV, B::RV, B::PV, B::PVIV, B::PVNV, B::PVMG, B::BM (5.9.5 and
-earlier), B::PVLV, B::AV, B::HV, B::CV, B::GV, B::FM, B::IO. These classes
+earlier), B::PVLV, B::AV, B::HV, B::CV, B::GV, B::FM, B::IO. These classes
correspond in the obvious way to the underlying C structures of similar names.
-The inheritance hierarchy mimics the underlying C "inheritance". For the
+The inheritance hierarchy mimics the underlying C "inheritance". For the
5.10.x branch, (I<ie> 5.10.0, 5.10.1 I<etc>) this is:
B::SV
Access methods correspond to the underlying C macros for field access,
usually with the leading "class indication" prefix removed (Sv, Av,
-Hv, ...). The leading prefix is only left in cases where its removal
-would cause a clash in method name. For example, C<GvREFCNT> stays
+Hv, ...). The leading prefix is only left in cases where its removal
+would cause a clash in method name. For example, C<GvREFCNT> stays
as-is since its abbreviation would clash with the "superclass" method
C<REFCNT> (corresponding to the C function C<SvREFCNT>).
=item object_2svref
Returns a reference to the regular scalar corresponding to this
-B::SV object. In other words, this method is the inverse operation
-to the svref_2object() subroutine. This scalar and other data it points
+B::SV object. In other words, this method is the inverse operation
+to the svref_2object() subroutine. This scalar and other data it points
at should be considered read-only: modifying them is neither safe nor
guaranteed to have a sensible effect.
=item IV
Returns the value of the IV, I<interpreted as
-a signed integer>. This will be misleading
-if C<FLAGS & SVf_IVisUV>. Perhaps you want the
+a signed integer>. This will be misleading
+if C<FLAGS & SVf_IVisUV>. Perhaps you want the
C<int_value> method instead?
=item IVX
=item PV
-This method is the one you usually want. It constructs a
+This method is the one you usually want. It constructs a
string using the length and offset information in the struct:
for ordinary scalars it will return the string that you'd see
from Perl, even if it contains null characters.
=item PVX
-This method is less often useful. It assumes that the string
+This method is less often useful. It assumes that the string
stored in the struct is null-terminated, and disregards the
length information.
It is the appropriate method to use if you need to get the name
-of a lexical variable from a padname array. Lexical variable names
+of a lexical variable from a padname array. Lexical variable names
are always stored with a null terminator, and the length field
-(SvCUR) is overloaded for other purposes and can't be relied on here.
+(CUR) is overloaded for other purposes and can't be relied on here.
+
+=item CUR
+
+This method returns the internal length field, which consists of the number
+of internal bytes, not necessarily the number of logical characters.
+
+=item LEN
+
+This method returns the number of bytes allocated (via malloc) for storing
+the string. This is 0 if the scalar does not "own" the string.
=back
=head2 B::IO Methods
+B::IO objects derive from IO objects and you will get more information from
+the IO object itself.
+
+For example:
+
+ $gvio = B::svref_2object(\*main::stdin)->IO;
+ $IO = $gvio->object_2svref();
+ $fd = $IO->fileno();
+
=over 4
=item LINES
=item IoTYPE
+A character symbolizing the type of IO Handle.
+
+ - STDIN/OUT
+ I STDIN/OUT/ERR
+ < read-only
+ > write-only
+ a append
+ + read and write
+ s socket
+ | pipe
+ I IMPLICIT
+ # NUMERIC
+ space closed handle
+ \0 closed internal handle
+
=item IoFLAGS
=item IsSTD
-Takes one arguments ( 'stdin' | 'stdout' | 'stderr' ) and returns true
+Takes one argument ( 'stdin' | 'stdout' | 'stderr' ) and returns true
if the IoIFP of the object is equal to the handle whose name was
-passed as argument ( i.e. $io->IsSTD('stderr') is true if
-IoIFP($io) == PerlIO_stdin() ).
+passed as argument; i.e., $io->IsSTD('stderr') is true if
+IoIFP($io) == PerlIO_stderr().
=back
=item AvFLAGS
-This method returns the AV specific flags. In Perl 5.9 these are now stored
+This method returns the AV specific
+flags. In Perl 5.9 these are now stored
in with the main SV flags, so this method is no longer present.
=back
C<B::SVOP>, C<B::PADOP>, C<B::PVOP>, C<B::LOOP>, C<B::COP>.
These classes correspond in the obvious way to the underlying C
-structures of similar names. The inheritance hierarchy mimics the
+structures of similar names. The inheritance hierarchy mimics the
underlying C "inheritance":
B::OP
/ \
B::LOOP B::PMOP
-Access methods correspond to the underlying C structre field names,
+Access methods correspond to the underlying C structure field names,
with the leading "class indication" prefix (C<"op_">) removed.
=head2 B::OP Methods
Only up to Perl 5.9.4
-=item pmregexp
-
=item pmflags
=item extflags
Only when perl was compiled with ithreads.
+=item code_list
+
+Since perl 5.17.1
+
=back
=head2 B::SVOP METHOD
=item stashpv
+=item stashoff (threaded only)
+
=item file
=item cop_seq
=back
+=head2 $B::overlay
+
+Although the optree is read-only, there is an overlay facility that allows
+you to override what values the various B::*OP methods return for a
+particular op. C<$B::overlay> should be set to reference a two-deep hash:
+indexed by OP address, then method name. Whenever a an op method is
+called, the value in the hash is returned if it exists. This facility is
+used by B::Deparse to "undo" some optimisations. For example:
+
+
+ local $B::overlay = {};
+ ...
+ if ($op->name eq "foo") {
+ $B::overlay->{$$op} = {
+ name => 'bar',
+ next => $op->next->next,
+ };
+ }
+ ...
+ $op->name # returns "bar"
+ $op->next # returns the next op but one
+
+
=head1 AUTHOR
Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>
https://perl5.git.perl.org / perl5.git / blobdiff