3 # Copyright (c) 1996 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.
7 package B::Disassembler::BytecodeStream;
10 use B qw(cstring cast_I32);
11 @ISA = qw(FileHandle);
15 read($fh, $data, $len);
16 croak "reached EOF while reading $len bytes" unless length($data) == $len;
23 croak "reached EOF while reading U8" unless defined($c);
29 my $str = $fh->readn(2);
30 croak "reached EOF while reading U16" unless length($str) == 2;
31 return unpack("n", $str);
36 my $str = $fh->readn(4);
37 croak "reached EOF while reading U32" unless length($str) == 4;
38 return unpack("N", $str);
43 my $str = $fh->readn(4);
44 croak "reached EOF while reading I32" unless length($str) == 4;
45 return cast_I32(unpack("N", $str));
50 my $str = $fh->readn(4);
51 croak "reached EOF while reading objindex" unless length($str) == 4;
52 return unpack("N", $str);
58 while (defined($c = $fh->getc) && $c ne "\0") {
61 croak "reached EOF while reading strconst" unless defined($c);
70 my $len = $fh->GET_U32;
72 read($fh, $str, $len);
73 croak "reached EOF while reading PV" unless length($str) == $len;
83 while (defined($c = $fh->getc) && $c ne "\n") {
86 croak "reached EOF while reading comment" unless defined($c);
93 while (defined($c = $fh->getc) && $c ne "\0") {
96 croak "reached EOF while reading double" unless defined($c);
102 sub GET_op_tr_array {
104 my @ary = unpack("n256", $fh->readn(256 * 2));
105 return join(",", @ary);
110 my ($hi, $lo) = unpack("NN", $fh->readn(8));
111 return sprintf("0x%4x%04x", $hi, $lo); # cheat
114 package B::Disassembler;
117 @EXPORT_OK = qw(disassemble_fh);
121 use B::Asmdata qw(%insn_data @insn_name);
125 my ($c, $getmeth, $insn, $arg);
126 bless $fh, "B::Disassembler::BytecodeStream";
127 while (defined($c = $fh->getc)) {
129 $insn = $insn_name[$c];
130 if (!defined($insn) || $insn eq "unused") {
131 my $pos = $fh->tell - 1;
132 die "Illegal instruction code $c at stream offset $pos\n";
134 $getmeth = $insn_data{$insn}->[2];
135 $arg = $fh->$getmeth();
150 B::Disassembler - Disassemble Perl bytecode
158 See F<ext/B/B/Disassembler.pm>.
162 Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>