disas: Add disas-objdump.pl

#!/usr/bin/perl -w

use File::Temp qw/ tempfile /;

use Getopt::Long;

# Default to the system objdump if a cross-compiler edition not given.

my $aobjdump = "objdump";

my $hobjdump = "";

my $tobjdump = "";

my $hmachine = "";

my $tmachine = "";

GetOptions ('O|objdump=s' => \$aobjdump,

            'host-objdump=s' => \$hobjdump,

            'target-objdump=s' => \$tobjdump,

            'h|host-machine=s' => \$hmachine,

            't|target-machine=s' => \$tmachine);

# But we can't default the machines.  Sanity check that we've at least one.

die "No host or target machine type" if !$hmachine && !$tmachine;

# Reuse one temp file for all of the hunks.

my ($outh, $outname) = tempfile();

binmode($outh);

END { unlink $outname; }

# Pre-construct the command-lines for executing the dump.

sub mkobjcommand ($$) {

    my ($cmd, $mach) = @_;

    return 0 if !$mach;

    $cmd = $aobjdump if !$cmd;

    return "$cmd -m $mach --disassemble-all -b binary $outname";

}

$objdump[1] = mkobjcommand($hobjdump, $hmachine);

$objdump[2] = mkobjcommand($tobjdump, $tmachine);

# Zero-initialize current dumping state.

my $mem = "";

my $inobjd = 0;

sub objcommand {

    my $ret = $objdump[$inobjd];

    if (!$ret) {

        die "Host machine type not specified" if $inobjd == 1;

        die "Target machine type not specified" if $inobjd == 2;

        die "Internal error";

    }

    return $ret;

}

while (<>) {

    # Collect the data from the relevant OBJD-* lines.

    if (/^OBJD-H: /) {

        die "Internal error" if $inobjd == 2;

        $mem = $mem . pack("H*", substr($_, 8, -1));

        $inobjd = 1;

    } elsif (/^OBJD-T: /) {

        die "Internal error" if $inobjd == 1;

        $mem = $mem . pack("H*", substr($_, 8, -1));

        $inobjd = 2;

    }

    # ... which will always be followed by a blank line,

    # at which point we should produce our dump.

    elsif ($inobjd) {

        # Rewrite the temp file in one go; it will usually be small.

        sysseek $outh, 0, 0;

        truncate $outh, 0;

        syswrite $outh, $mem;

        # Pipe from objdump...

        open IN, "-|", objcommand();

        # ... copying all but the first 7 lines of boilerplate to our stdout.

	my $i = 0;

	while (<IN>) {

	    print if (++$i > 7);

        }

        close IN;

        print "\n";

        $mem = "";

        $inobjd = 0;

    } else {

        print;

    }

}