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1#!/usr/bin/env perl2 3use Getopt::Std;4$DEBUG = 0;5 6sub parse_objdump_file {7 my ($filename) = @_;8 my @result;9 open (INPUT, $filename) or die "$filename: $!\n";10 print "opened objdump output file $filename\n" if $DEBUG;11 while (<INPUT>) {12 if (/\s*([0-9a-f]*):\t(([0-9a-f]{2} )+) *\t(.*)$/) {13 my ($addr, $bytes, $instr) = ($1, $2, $4);14 $addr = "0x" . $addr;15 $bytes =~ s/\s*(.*\S)\s*/$1/; # trim any remaining whitespace16 $instr =~ s/\s*(.*\S)\s*/$1/;17 push (@result, {'addr' => $addr, 'bytes' => $bytes, 'instr' => $instr});18 print "addr=$addr bytes='$bytes' instr='$instr'\n" if $DEBUG;19 }20 }21 close INPUT;22 return @result;23}24 25sub parse_gdb_file {26 my ($filename) = @_;27 my @result;28 my $got_addr;29 open (INPUT, $filename) or die "$filename: $!\n";30 print "opened gdb output file $filename\n" if $DEBUG;31 while (<INPUT>) {32 if (/^(0x[0-9a-f]*):\t([^\t]*)\t[^:]*:\t((0x[0-9a-f]{2}\s*)+)\s*$/) {33 my ($addr, $bytes, $instr) = ($1, $3, $2);34 $bytes =~ s/0x//g;35 $bytes =~ s/\s+/ /g; # regularize whitespace36 $bytes =~ s/\s*(.*\S)\s*/$1/; # trim any remaining whitespace37 $instr =~ s/\s*(.*\S)\s*/$1/;38 push (@result, {'addr' => $addr, 'bytes' => $bytes, 'instr' => $instr});39 print "addr=$addr bytes='$bytes' instr='$instr'\n" if $DEBUG;40 } elsif (/^(0x[0-9a-f]*):\t$/) { # deal with gdb's line breaker41 $got_addr = $1;42 } elsif ($got_addr && /^ ([^\t]*)\t[^:]*:\t((0x[0-9a-f]{2}\s*)+)\s*$/) {43 my ($addr, $bytes, $instr) = ($got_addr, $2, $1);44 $bytes =~ s/0x//g;45 $bytes =~ s/\s+/ /g; # regularize whitespace46 $bytes =~ s/\s*(.*\S)\s*/$1/; # trim any remaining whitespace47 $instr =~ s/\s*(.*\S)\s*/$1/;48 push (@result, {'addr' => $addr, 'bytes' => $bytes, 'instr' => $instr});49 print "addr=$addr bytes='$bytes' instr='$instr'\n" if $DEBUG;50 undef $got_addr;51 }52 }53 close INPUT;54 return @result;55}56 57sub binary_diffs {58 my ($objdump_file, $gdb_file) = @_;59 my @file1 = parse_objdump_file ($objdump_file);60 my @file2 = parse_gdb_file ($gdb_file);61 my $lastrecord = ($#file1 >= $#file2) ? ($#file1) : ($#file2);62 for (my $i = 0; $i <= $lastrecord; ++$i) {63 my $d1 = $file1[$i];64 my $d2 = $file2[$i];65 if ($d1->{'bytes'} ne $d2->{'bytes'}) {66 next if (($d1->{'instr'} eq $d2->{'instr'}) && $opt_d);67 printf "0x%08x:\t%30s \t%s\n", 0+$d1->{'addr'}, $d1->{'bytes'}, $d1->{'instr'};68 printf "0x%08x:\t%30s \t%s\n\n", 0+$d2->{'addr'}, $d2->{'bytes'}, $d2->{'instr'};69 }70 }71}72 73&getopts('d');74$objdump_file = $ARGV[0];75$gdb_file = $ARGV[1];76binary_diffs ($objdump_file, $gdb_file);77exit (0);78__END__79=pod80 81=head1 NAME82 83codegen-diff84 85=head1 SYNOPSIS86 87codegen-diff [-d] I<OBJDUMP-OUTPUT-FILE> I<GDB-DISASSEMBLY-FILE>88 89=head1 DESCRIPTION90 91B<codegen-diff> is a program that tries to show you the differences92between the code that B<llc> generated and the code that B<lli> generated.93 94The way you use it is as follows: first, you create I<OBJDUMP-OUTPUT-FILE>95by running B<objdump> on the B<llc> compiled and linked binary. You need to96trim down the result so it contains only the function of interest.97 98Second, you create I<GDB-DISASSEMBLY-FILE> by running B<gdb>, with my patch99to print out hex bytes in the B<disassemble> command output, on100B<lli>. Set a breakpoint in C<Emitter::finishFunction()> and wait until101the function you want is compiled. Then use the B<disassemble> command102to print out the assembly dump of the function B<lli> just compiled.103(Use C<lli -debug> to find out where the function starts and ends in memory.)104It's easiest to save this output by using B<script>.105 106Finally, you run B<codegen-diff>, as indicated in the Synopsis section of107this manpage. It will print out a two-line stanza for each mismatched108instruction, with the B<llc> version first, and the B<lli> version second.109 110=head1 OPTIONS111 112=over 4113 114=item -d115 116Don't show instructions where the bytes are different but they117disassemble to the same thing. This puts a lot of trust in the118disassembler, but it might help you highlight the more egregious cases119of misassembly.120 121=back122 123=head1 AUTHOR124 125B<codegen-diff> was written by Brian Gaeke.126 127=head1 SEE ALSO128 129L<gdb(1)>, L<objdump(1)>, L<script(1)>.130 131You will need my B<gdb> patch:132 133 http://llvm.cs.uiuc.edu/~gaeke/gdb-disassembly-print-bytes.patch134 135=cut136