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.IX Title "B::Bblock 3"
.TH B::Bblock 3 "2002-11-24" "perl v5.8.0" "Perl Programmers Reference Guide"
.SH "NAME"
B::Bblock \- Walk basic blocks
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\&  # External interface
\&  perl -MO=Bblock[,OPTIONS] foo.pl
.Ve
.PP
.Vb 3
\&  # Programmatic API
\&  use B::Bblock qw(find_leaders);
\&  my $leaders = find_leaders($root_op, $start_op);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This module is used by the B::CC back end.  It walks \*(L"basic blocks\*(R".
A basic block is a series of operations which is known to execute from
start to finish, with no possiblity of branching or halting.
.PP
It can be used either stand alone or from inside another program.
.Sh "Functions"
.IX Subsection "Functions"
.IP "\fBfind_leaders\fR" 4
.IX Item "find_leaders"
.Vb 1
\&  my $leaders = find_leaders($root_op, $start_op);
.Ve
.Sp
Given the root of the op tree and an op from which to start
processing, it will return a hash ref representing all the ops which
start a block.
.Sp
The values of %$leaders are the op objects themselves.  Keys are $$op
addresses.
.SH "AUTHOR"
.IX Header "AUTHOR"
Malcolm Beattie, \f(CW\*(C`mbeattie@sable.ox.ac.uk\*(C'\fR