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1 | # Disassembler.pm |
2 | # |
3 | # Copyright (c) 1996 Malcolm Beattie |
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 | package B::Disassembler::BytecodeStream; |
8 | use FileHandle; |
9 | use Carp; |
10 | use B qw(cstring cast_I32); |
11 | @ISA = qw(FileHandle); |
12 | sub readn { |
13 | my ($fh, $len) = @_; |
14 | my $data; |
15 | read($fh, $data, $len); |
16 | croak "reached EOF while reading $len bytes" unless length($data) == $len; |
17 | return $data; |
18 | } |
19 | |
20 | sub GET_U8 { |
21 | my $fh = shift; |
22 | my $c = $fh->getc; |
23 | croak "reached EOF while reading U8" unless defined($c); |
24 | return ord($c); |
25 | } |
26 | |
27 | sub GET_U16 { |
28 | my $fh = shift; |
29 | my $str = $fh->readn(2); |
30 | croak "reached EOF while reading U16" unless length($str) == 2; |
31 | return unpack("n", $str); |
32 | } |
33 | |
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34 | sub GET_NV { |
35 | my $fh = shift; |
36 | my $str = $fh->readn(8); |
37 | croak "reached EOF while reading NV" unless length($str) == 8; |
38 | return unpack("N", $str); |
39 | } |
40 | |
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41 | sub GET_U32 { |
42 | my $fh = shift; |
43 | my $str = $fh->readn(4); |
44 | croak "reached EOF while reading U32" unless length($str) == 4; |
45 | return unpack("N", $str); |
46 | } |
47 | |
48 | sub GET_I32 { |
49 | my $fh = shift; |
50 | my $str = $fh->readn(4); |
51 | croak "reached EOF while reading I32" unless length($str) == 4; |
52 | return cast_I32(unpack("N", $str)); |
53 | } |
54 | |
55 | sub GET_objindex { |
56 | my $fh = shift; |
57 | my $str = $fh->readn(4); |
58 | croak "reached EOF while reading objindex" unless length($str) == 4; |
59 | return unpack("N", $str); |
60 | } |
61 | |
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62 | sub GET_opindex { |
63 | my $fh = shift; |
64 | my $str = $fh->readn(4); |
65 | croak "reached EOF while reading opindex" unless length($str) == 4; |
66 | return unpack("N", $str); |
67 | } |
68 | |
69 | sub GET_svindex { |
70 | my $fh = shift; |
71 | my $str = $fh->readn(4); |
72 | croak "reached EOF while reading svindex" unless length($str) == 4; |
73 | return unpack("N", $str); |
74 | } |
75 | |
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76 | sub GET_strconst { |
77 | my $fh = shift; |
78 | my ($str, $c); |
79 | while (defined($c = $fh->getc) && $c ne "\0") { |
80 | $str .= $c; |
81 | } |
82 | croak "reached EOF while reading strconst" unless defined($c); |
83 | return cstring($str); |
84 | } |
85 | |
86 | sub GET_pvcontents {} |
87 | |
88 | sub GET_PV { |
89 | my $fh = shift; |
90 | my $str; |
91 | my $len = $fh->GET_U32; |
92 | if ($len) { |
93 | read($fh, $str, $len); |
94 | croak "reached EOF while reading PV" unless length($str) == $len; |
95 | return cstring($str); |
96 | } else { |
97 | return '""'; |
98 | } |
99 | } |
100 | |
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101 | sub GET_comment_t { |
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102 | my $fh = shift; |
103 | my ($str, $c); |
104 | while (defined($c = $fh->getc) && $c ne "\n") { |
105 | $str .= $c; |
106 | } |
107 | croak "reached EOF while reading comment" unless defined($c); |
108 | return cstring($str); |
109 | } |
110 | |
111 | sub GET_double { |
112 | my $fh = shift; |
113 | my ($str, $c); |
114 | while (defined($c = $fh->getc) && $c ne "\0") { |
115 | $str .= $c; |
116 | } |
117 | croak "reached EOF while reading double" unless defined($c); |
118 | return $str; |
119 | } |
120 | |
121 | sub GET_none {} |
122 | |
123 | sub GET_op_tr_array { |
124 | my $fh = shift; |
125 | my @ary = unpack("n256", $fh->readn(256 * 2)); |
126 | return join(",", @ary); |
127 | } |
128 | |
129 | sub GET_IV64 { |
130 | my $fh = shift; |
131 | my ($hi, $lo) = unpack("NN", $fh->readn(8)); |
132 | return sprintf("0x%4x%04x", $hi, $lo); # cheat |
133 | } |
134 | |
135 | package B::Disassembler; |
136 | use Exporter; |
137 | @ISA = qw(Exporter); |
138 | @EXPORT_OK = qw(disassemble_fh); |
139 | use Carp; |
140 | use strict; |
141 | |
142 | use B::Asmdata qw(%insn_data @insn_name); |
143 | |
144 | sub disassemble_fh { |
145 | my ($fh, $out) = @_; |
146 | my ($c, $getmeth, $insn, $arg); |
147 | bless $fh, "B::Disassembler::BytecodeStream"; |
148 | while (defined($c = $fh->getc)) { |
149 | $c = ord($c); |
150 | $insn = $insn_name[$c]; |
151 | if (!defined($insn) || $insn eq "unused") { |
152 | my $pos = $fh->tell - 1; |
153 | die "Illegal instruction code $c at stream offset $pos\n"; |
154 | } |
155 | $getmeth = $insn_data{$insn}->[2]; |
156 | $arg = $fh->$getmeth(); |
157 | if (defined($arg)) { |
158 | &$out($insn, $arg); |
159 | } else { |
160 | &$out($insn); |
161 | } |
162 | } |
163 | } |
164 | |
165 | 1; |
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166 | |
167 | __END__ |
168 | |
169 | =head1 NAME |
170 | |
171 | B::Disassembler - Disassemble Perl bytecode |
172 | |
173 | =head1 SYNOPSIS |
174 | |
175 | use Disassembler; |
176 | |
177 | =head1 DESCRIPTION |
178 | |
179 | See F<ext/B/B/Disassembler.pm>. |
180 | |
181 | =head1 AUTHOR |
182 | |
183 | Malcolm Beattie, C<mbeattie@sable.ox.ac.uk> |
184 | |
185 | =cut |