--- /dev/null
+#!/usr/bin/perl -w
+
+# Copyright (C) 2014 Apple Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution.
+# 3. Neither the name of Apple puter, Inc. ("Apple") nor the names of
+# its contributors may be used to endorse or promote products derived
+# from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+use strict;
+use Cwd;
+use File::Path qw(make_path);
+use File::Spec;
+
+my $PWD = Cwd::cwd();
+my $XSRCROOT = Cwd::realpath(File::Spec->catdir($PWD, '..', '..', '..'));
+$ENV{'XSRCROOT'} = $XSRCROOT;
+$ENV{'SRCROOT'} = $XSRCROOT;
+
+# Make sure we don't have any leading or trailing quotes
+$ARGV[0] =~ s/^\"//;
+$ARGV[0] =~ s/\"$//;
+
+my $XDSTROOT = Cwd::realpath($ARGV[0]);
+$ENV{'XDSTROOT'} = $XDSTROOT;
+
+my $BUILD_PRODUCTS_DIR = File::Spec->catdir($XDSTROOT, "obj$ARGV[3]");
+$ENV{'BUILT_PRODUCTS_DIR'} = $BUILD_PRODUCTS_DIR;
+
+my $DERIVED_SOURCES_DIR = File::Spec->catdir($BUILD_PRODUCTS_DIR, 'JavaScriptCore', 'DerivedSources');
+unless (-d $DERIVED_SOURCES_DIR) {
+ make_path($DERIVED_SOURCES_DIR) or die "Couldn't create $DERIVED_SOURCES_DIR: $!";
+}
+
+chdir $DERIVED_SOURCES_DIR or die "Couldn't change directory to $DERIVED_SOURCES_DIR: $!";
+
+# Create a dummy asm file in case we are using the C backend
+# This is needed since LowLevelInterpreterWin.asm is part of the project.
+my $LowLevelInterpreterWin = File::Spec->catfile($DERIVED_SOURCES_DIR, 'LowLevelInterpreterWin.asm');
+
+open(OUTPUTFILENAME, '>', $LowLevelInterpreterWin) or die "Couldn't open $LowLevelInterpreterWin to write: $!";
+print OUTPUTFILENAME "END\n";
+close(OUTPUTFILENAME);
+
+# If you want to enable the LLINT C loop, set OUTPUTFILENAME to "LLIntAssembly.h"
+my $OUTPUTFILENAME = File::Spec->catfile($DERIVED_SOURCES_DIR, 'LowLevelInterpreterWin.asm');
+
+my $offlineAsm = File::Spec->catfile($XSRCROOT, 'offlineasm', 'asm.rb');
+my $lowLevelInterpreter = File::Spec->catfile($XSRCROOT, 'llint', 'LowLevelInterpreter.asm');
+my $offsetsExtractor = File::Spec->catfile($BUILD_PRODUCTS_DIR, 'LLIntOffsetsExtractor', "LLIntOffsetsExtractor$ARGV[2].exe");
+system('/usr/bin/env', 'ruby', $offlineAsm, '-I.', $lowLevelInterpreter, $offsetsExtractor, $OUTPUTFILENAME) and die "Failed to generate $OUTPUTFILENAME: $!";