| #!/usr/bin/env perl |
| |
| use Getopt::Std; |
| $DEBUG = 0; |
| |
| sub parse_objdump_file { |
| my ($filename) = @_; |
| my @result; |
| open (INPUT, $filename) or die "$filename: $!\n"; |
| print "opened objdump output file $filename\n" if $DEBUG; |
| while (<INPUT>) { |
| if (/\s*([0-9a-f]*):\t(([0-9a-f]{2} )+) *\t(.*)$/) { |
| my ($addr, $bytes, $instr) = ($1, $2, $4); |
| $addr = "0x" . $addr; |
| $bytes =~ s/\s*(.*\S)\s*/$1/; # trim any remaining whitespace |
| $instr =~ s/\s*(.*\S)\s*/$1/; |
| push (@result, {'addr' => $addr, 'bytes' => $bytes, 'instr' => $instr}); |
| print "addr=$addr bytes='$bytes' instr='$instr'\n" if $DEBUG; |
| } |
| } |
| close INPUT; |
| return @result; |
| } |
| |
| sub parse_gdb_file { |
| my ($filename) = @_; |
| my @result; |
| my $got_addr; |
| open (INPUT, $filename) or die "$filename: $!\n"; |
| print "opened gdb output file $filename\n" if $DEBUG; |
| while (<INPUT>) { |
| if (/^(0x[0-9a-f]*):\t([^\t]*)\t[^:]*:\t((0x[0-9a-f]{2}\s*)+)\s*$/) { |
| my ($addr, $bytes, $instr) = ($1, $3, $2); |
| $bytes =~ s/0x//g; |
| $bytes =~ s/\s+/ /g; # regularize whitespace |
| $bytes =~ s/\s*(.*\S)\s*/$1/; # trim any remaining whitespace |
| $instr =~ s/\s*(.*\S)\s*/$1/; |
| push (@result, {'addr' => $addr, 'bytes' => $bytes, 'instr' => $instr}); |
| print "addr=$addr bytes='$bytes' instr='$instr'\n" if $DEBUG; |
| } elsif (/^(0x[0-9a-f]*):\t$/) { # deal with gdb's line breaker |
| $got_addr = $1; |
| } elsif ($got_addr && /^ ([^\t]*)\t[^:]*:\t((0x[0-9a-f]{2}\s*)+)\s*$/) { |
| my ($addr, $bytes, $instr) = ($got_addr, $2, $1); |
| $bytes =~ s/0x//g; |
| $bytes =~ s/\s+/ /g; # regularize whitespace |
| $bytes =~ s/\s*(.*\S)\s*/$1/; # trim any remaining whitespace |
| $instr =~ s/\s*(.*\S)\s*/$1/; |
| push (@result, {'addr' => $addr, 'bytes' => $bytes, 'instr' => $instr}); |
| print "addr=$addr bytes='$bytes' instr='$instr'\n" if $DEBUG; |
| undef $got_addr; |
| } |
| } |
| close INPUT; |
| return @result; |
| } |
| |
| sub binary_diffs { |
| my ($objdump_file, $gdb_file) = @_; |
| my @file1 = parse_objdump_file ($objdump_file); |
| my @file2 = parse_gdb_file ($gdb_file); |
| my $lastrecord = ($#file1 >= $#file2) ? ($#file1) : ($#file2); |
| for (my $i = 0; $i <= $lastrecord; ++$i) { |
| my $d1 = $file1[$i]; |
| my $d2 = $file2[$i]; |
| if ($d1->{'bytes'} ne $d2->{'bytes'}) { |
| next if (($d1->{'instr'} eq $d2->{'instr'}) && $opt_d); |
| printf "0x%08x:\t%30s \t%s\n", 0+$d1->{'addr'}, $d1->{'bytes'}, $d1->{'instr'}; |
| printf "0x%08x:\t%30s \t%s\n\n", 0+$d2->{'addr'}, $d2->{'bytes'}, $d2->{'instr'}; |
| } |
| } |
| } |
| |
| &getopts('d'); |
| $objdump_file = $ARGV[0]; |
| $gdb_file = $ARGV[1]; |
| binary_diffs ($objdump_file, $gdb_file); |
| exit (0); |
| __END__ |
| =pod |
| |
| =head1 NAME |
| |
| codegen-diff |
| |
| =head1 SYNOPSIS |
| |
| codegen-diff [-d] I<OBJDUMP-OUTPUT-FILE> I<GDB-DISASSEMBLY-FILE> |
| |
| =head1 DESCRIPTION |
| |
| B<codegen-diff> is a program that tries to show you the differences |
| between the code that B<llc> generated and the code that B<lli> generated. |
| |
| The way you use it is as follows: first, you create I<OBJDUMP-OUTPUT-FILE> |
| by running B<objdump> on the B<llc> compiled and linked binary. You need to |
| trim down the result so it contains only the function of interest. |
| |
| Second, you create I<GDB-DISASSEMBLY-FILE> by running B<gdb>, with my patch |
| to print out hex bytes in the B<disassemble> command output, on |
| B<lli>. Set a breakpoint in C<Emitter::finishFunction()> and wait until |
| the function you want is compiled. Then use the B<disassemble> command |
| to print out the assembly dump of the function B<lli> just compiled. |
| (Use C<lli -debug> to find out where the function starts and ends in memory.) |
| It's easiest to save this output by using B<script>. |
| |
| Finally, you run B<codegen-diff>, as indicated in the Synopsis section of |
| this manpage. It will print out a two-line stanza for each mismatched |
| instruction, with the B<llc> version first, and the B<lli> version second. |
| |
| =head1 OPTIONS |
| |
| =over 4 |
| |
| =item -d |
| |
| Don't show instructions where the bytes are different but they |
| disassemble to the same thing. This puts a lot of trust in the |
| disassembler, but it might help you highlight the more egregious cases |
| of misassembly. |
| |
| =back |
| |
| =head1 AUTHOR |
| |
| B<codegen-diff> was written by Brian Gaeke. |
| |
| =head1 SEE ALSO |
| |
| L<gdb(1)>, L<objdump(1)>, L<script(1)>. |
| |
| You will need my B<gdb> patch: |
| |
| http://llvm.cs.uiuc.edu/~gaeke/gdb-disassembly-print-bytes.patch |
| |
| =cut |