diff --git a/build.py b/build.py
index f22e821..37ad19c 100755
--- a/build.py
+++ b/build.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# Copyright (C) 2017 The Android Open Source Project
+# Copyright (C) 2018 The Android Open Source Project
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -14,268 +14,33 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-"""Builds binutils."""
-from __future__ import print_function
-
-import argparse
+"""Bootstrapper for do_build.py."""
 import logging
-import multiprocessing
 import os
-import shutil
 import site
 import subprocess
+import sys
 
 
 THIS_DIR = os.path.realpath(os.path.dirname(__file__))
-site.addsitedir(os.path.join(THIS_DIR, '../../ndk'))
-
-# pylint: disable=wrong-import-position
-import ndk.abis  # pylint: disable=import-error
-import ndk.ext.shutil  # pylint: disable=import-error
-import ndk.paths  # pylint: disable=import-error
-import ndk.timer  # pylint: disable=import-error
-# pylint: enable=wrong-import-position
+ANDROID_TOP = os.path.join(THIS_DIR, '../..')
 
 
-def logger():
-    """Returns the module level logger."""
-    return logging.getLogger(__name__)
-
-
-def makedirs(path):
-    """os.makedirs with logging."""
-    logger().info('makedirs ' + path)
-    os.makedirs(path)
-
-
-def rmtree(path):
-    """shutil.rmtree with logging."""
-    logger().info('rmtree ' + path)
-    shutil.rmtree(path)
-
-
-def chdir(path):
-    """os.chdir with logging."""
-    logger().info('chdir ' + path)
-    os.chdir(path)
-
-
-def install_file(src, dst):
-    """shutil.copy2 with logging."""
-    logger().info('copy %s %s', src, dst)
-    shutil.copy2(src, dst)
-
-
-def check_call(cmd, *args, **kwargs):
-    """subprocess.check_call with logging."""
-    logger().info('check_call %s', subprocess.list2cmdline(cmd))
-    subprocess.check_call(cmd, *args, **kwargs)
-
-
-def configure(arch, host, install_dir, src_dir):
-    """Configures binutils."""
-    is_windows = host in ('win', 'win64')
-
-    configure_host = {
-        'darwin': 'x86_64-apple-darwin',
-        'linux': 'x86_64-linux-gnu',
-        'win': 'i686-w64-mingw32',
-        'win64': 'x86_64-w64-mingw32',
-    }[host]
-
-    sysroot = ndk.paths.sysroot_path(ndk.abis.arch_to_toolchain(arch))
-    configure_args = [
-        os.path.join(src_dir, 'configure'),
-        '--target={}'.format(ndk.abis.arch_to_triple(arch)),
-        '--host={}'.format(configure_host),
-        '--enable-initfini-array',
-        '--enable-plugins',
-        '--enable-threads',
-        '--disable-nls',
-        '--with-sysroot={}'.format(sysroot),
-        '--prefix={}'.format(install_dir),
-    ]
-
-    if arch == 'arm64':
-        configure_args.append('--enable-fix-cortex-a53-835769')
-        configure_args.append('--enable-gold')
-    else:
-        # Gold for aarch64 currently emits broken debug info.
-        # https://issuetracker.google.com/70838247
-        configure_args.append('--enable-gold=default')
-
-    env = {}
-
-    m32 = False
-    if host == 'darwin':
-        toolchain = ndk.paths.android_path(
-            'prebuilts/gcc/darwin-x86/host/i686-apple-darwin-4.2.1')
-        toolchain_prefix = 'i686-apple-darwin10'
-        env['MACOSX_DEPLOYMENT_TARGET'] = '10.6'
-    elif host == 'linux':
-        toolchain = ndk.paths.android_path(
-            'prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.15-4.8')
-        toolchain_prefix = 'x86_64-linux'
-    elif is_windows:
-        toolchain = ndk.paths.android_path(
-            'prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8')
-        toolchain_prefix = 'x86_64-w64-mingw32'
-        if host == 'win':
-            m32 = True
-    else:
-        raise NotImplementedError
-
-    cc = os.path.join(toolchain, 'bin', '{}-gcc'.format(toolchain_prefix))
-    cxx = os.path.join(toolchain, 'bin', '{}-g++'.format(toolchain_prefix))
-
-    # Our darwin prebuilts are gcc *only*. No binutils.
-    if host == 'darwin':
-        ar = 'ar'
-        strip = 'strip'
-    else:
-        ar = os.path.join(toolchain, 'bin', '{}-ar'.format(toolchain_prefix))
-        strip = os.path.join(
-            toolchain, 'bin', '{}-strip'.format(toolchain_prefix))
-
-    env['AR'] = ar
-    env['CC'] = cc
-    env['CXX'] = cxx
-    env['STRIP'] = strip
-    if m32:
-        env['CFLAGS'] = '-m32'
-        env['CXXFLAGS'] = '-m32'
-        env['LDFLAGS'] = '-m32'
-    else:
-        env['CFLAGS'] = '-m64'
-        env['CXXFLAGS'] = '-m64'
-        env['LDFLAGS'] = '-m64'
-
-    env_args = ['env'] + ['='.join([k, v]) for k, v in env.items()]
-    check_call(env_args + configure_args)
-
-
-def build(jobs):
-    """Builds binutils."""
-    check_call(['make', '-j', str(jobs)])
-
-
-def install_winpthreads(is_windows32, install_dir):
-    """Installs the winpthreads runtime to the Windows bin directory."""
-    lib_name = 'libwinpthread-1.dll'
-    mingw_dir = ndk.paths.android_path(
-        'prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8',
-        'x86_64-w64-mingw32')
-    # Yes, this indeed may be found in bin/ because the executables are the
-    # 64-bit version by default.
-    pthread_dir = 'lib32' if is_windows32 else 'bin'
-    lib_path = os.path.join(mingw_dir, pthread_dir, lib_name)
-
-    lib_install = os.path.join(install_dir, 'bin', lib_name)
-    install_file(lib_path, lib_install)
-
-
-def install(jobs, arch, host, install_dir):
-    """Installs binutils."""
-    check_call(['make', 'install-strip', '-j', str(jobs)])
-
-    if host in ('win', 'win64'):
-        arch_install_dir = os.path.join(
-            install_dir, ndk.abis.arch_to_triple(arch))
-        install_winpthreads(host == 'win', install_dir)
-        install_winpthreads(host == 'win', arch_install_dir)
-
-
-def dist(dist_dir, base_dir, package_name):
-    """Packages binutils for distribution."""
-    has_pbzip2 = ndk.ext.shutil.which('pbzip2') is not None
-    if has_pbzip2:
-        compress_arg = '--use-compress-prog=pbzip2'
-    else:
-        compress_arg = '-j'
-
-    package_path = os.path.join(dist_dir, package_name + '.tar.bz2')
-    cmd = [
-        'tar', compress_arg, '-cf', package_path, '-C', base_dir, package_name,
-    ]
-    subprocess.check_call(cmd)
-
-
-def parse_args():
-    """Parse command line arguments."""
-    parser = argparse.ArgumentParser()
-
-    parser.add_argument(
-        '--arch', choices=ndk.abis.ALL_ARCHITECTURES, required=True)
-    parser.add_argument(
-        '--host', choices=('darwin', 'linux', 'win', 'win64'), required=True)
-
-    parser.add_argument(
-        '--clean', action='store_true',
-        help='Clean the out directory before building.')
-    parser.add_argument(
-        '-j', '--jobs', type=int, default=multiprocessing.cpu_count(),
-        help='Number of jobs to use when building.')
-
-    return parser.parse_args()
+site.addsitedir(os.path.join(ANDROID_TOP, 'ndk'))
+import bootstrap  # pylint: disable=import-error,wrong-import-position
 
 
 def main():
-    """Program entry point."""
-    args = parse_args()
+    """Program entry point.
+
+    Bootstraps the do_build.py with Python 3.
+    """
     logging.basicConfig(level=logging.INFO)
 
-    total_timer = ndk.timer.Timer()
-    total_timer.start()
-
-    out_dir = ndk.paths.get_out_dir()
-    dist_dir = ndk.paths.get_dist_dir(out_dir)
-    base_build_dir = os.path.join(
-        out_dir, 'binutils', args.host, args.arch)
-    build_dir = os.path.join(base_build_dir, 'build')
-    package_name = 'binutils-{}-{}'.format(args.arch, args.host)
-    install_dir = os.path.join(base_build_dir, 'install', package_name)
-    binutils_path = os.path.join(THIS_DIR, 'binutils-2.27')
-
-    did_clean = False
-    clean_timer = ndk.timer.Timer()
-    if args.clean and os.path.exists(build_dir):
-        did_clean = True
-        with clean_timer:
-            rmtree(build_dir)
-
-    if not os.path.exists(build_dir):
-        makedirs(build_dir)
-
-    orig_dir = os.getcwd()
-    chdir(build_dir)
-    try:
-        configure_timer = ndk.timer.Timer()
-        with configure_timer:
-            configure(args.arch, args.host, install_dir, binutils_path)
-
-        build_timer = ndk.timer.Timer()
-        with build_timer:
-            build(args.jobs)
-
-        install_timer = ndk.timer.Timer()
-        with install_timer:
-            install(args.jobs, args.arch, args.host, install_dir)
-    finally:
-        chdir(orig_dir)
-
-    package_timer = ndk.timer.Timer()
-    with package_timer:
-        dist(dist_dir, os.path.dirname(install_dir), package_name)
-
-    total_timer.finish()
-
-    if did_clean:
-        print('Clean: {}'.format(clean_timer.duration))
-    print('Configure: {}'.format(configure_timer.duration))
-    print('Build: {}'.format(build_timer.duration))
-    print('Install: {}'.format(install_timer.duration))
-    print('Package: {}'.format(package_timer.duration))
-    print('Total: {}'.format(total_timer.duration))
+    bootstrap.bootstrap()
+    subprocess.check_call(
+        ['python3', os.path.join(THIS_DIR, 'do_build.py')] +
+        sys.argv[1:])
 
 
 if __name__ == '__main__':
diff --git a/do_build.py b/do_build.py
new file mode 100755
index 0000000..9e0b41c
--- /dev/null
+++ b/do_build.py
@@ -0,0 +1,280 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2017 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+"""Builds binutils."""
+import argparse
+import logging
+import multiprocessing
+import os
+import shutil
+import site
+import subprocess
+
+
+THIS_DIR = os.path.realpath(os.path.dirname(__file__))
+site.addsitedir(os.path.join(THIS_DIR, '../../ndk'))
+
+# pylint: disable=wrong-import-position
+import ndk.abis  # pylint: disable=import-error
+import ndk.ext.shutil  # pylint: disable=import-error
+import ndk.paths  # pylint: disable=import-error
+import ndk.timer  # pylint: disable=import-error
+# pylint: enable=wrong-import-position
+
+
+def logger():
+    """Returns the module level logger."""
+    return logging.getLogger(__name__)
+
+
+def makedirs(path):
+    """os.makedirs with logging."""
+    logger().info('makedirs %s', path)
+    os.makedirs(path)
+
+
+def rmtree(path):
+    """shutil.rmtree with logging."""
+    logger().info('rmtree %s', path)
+    shutil.rmtree(path)
+
+
+def chdir(path):
+    """os.chdir with logging."""
+    logger().info('chdir %s', path)
+    os.chdir(path)
+
+
+def install_file(src, dst):
+    """shutil.copy2 with logging."""
+    logger().info('copy %s %s', src, dst)
+    shutil.copy2(src, dst)
+
+
+def check_call(cmd, *args, **kwargs):
+    """subprocess.check_call with logging."""
+    logger().info('check_call %s', subprocess.list2cmdline(cmd))
+    subprocess.check_call(cmd, *args, **kwargs)
+
+
+def configure(arch, host, install_dir, src_dir):
+    """Configures binutils."""
+    is_windows = host in ('win', 'win64')
+
+    configure_host = {
+        'darwin': 'x86_64-apple-darwin',
+        'linux': 'x86_64-linux-gnu',
+        'win': 'i686-w64-mingw32',
+        'win64': 'x86_64-w64-mingw32',
+    }[host]
+
+    sysroot = ndk.paths.sysroot_path(ndk.abis.arch_to_toolchain(arch))
+    configure_args = [
+        os.path.join(src_dir, 'configure'),
+        '--target={}'.format(ndk.abis.arch_to_triple(arch)),
+        '--host={}'.format(configure_host),
+        '--enable-initfini-array',
+        '--enable-plugins',
+        '--enable-threads',
+        '--disable-nls',
+        '--with-sysroot={}'.format(sysroot),
+        '--prefix={}'.format(install_dir),
+    ]
+
+    if arch == 'arm64':
+        configure_args.append('--enable-fix-cortex-a53-835769')
+        configure_args.append('--enable-gold')
+    else:
+        # Gold for aarch64 currently emits broken debug info.
+        # https://issuetracker.google.com/70838247
+        configure_args.append('--enable-gold=default')
+
+    env = {}
+
+    m32 = False
+    if host == 'darwin':
+        toolchain = ndk.paths.android_path(
+            'prebuilts/gcc/darwin-x86/host/i686-apple-darwin-4.2.1')
+        toolchain_prefix = 'i686-apple-darwin10'
+        env['MACOSX_DEPLOYMENT_TARGET'] = '10.6'
+    elif host == 'linux':
+        toolchain = ndk.paths.android_path(
+            'prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.15-4.8')
+        toolchain_prefix = 'x86_64-linux'
+    elif is_windows:
+        toolchain = ndk.paths.android_path(
+            'prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8')
+        toolchain_prefix = 'x86_64-w64-mingw32'
+        if host == 'win':
+            m32 = True
+    else:
+        raise NotImplementedError
+
+    cc = os.path.join(toolchain, 'bin', '{}-gcc'.format(toolchain_prefix))
+    cxx = os.path.join(toolchain, 'bin', '{}-g++'.format(toolchain_prefix))
+
+    # Our darwin prebuilts are gcc *only*. No binutils.
+    if host == 'darwin':
+        ar = 'ar'
+        strip = 'strip'
+    else:
+        ar = os.path.join(toolchain, 'bin', '{}-ar'.format(toolchain_prefix))
+        strip = os.path.join(
+            toolchain, 'bin', '{}-strip'.format(toolchain_prefix))
+
+    env['AR'] = ar
+    env['CC'] = cc
+    env['CXX'] = cxx
+    env['STRIP'] = strip
+    if m32:
+        env['CFLAGS'] = '-m32'
+        env['CXXFLAGS'] = '-m32'
+        env['LDFLAGS'] = '-m32'
+    else:
+        env['CFLAGS'] = '-m64'
+        env['CXXFLAGS'] = '-m64'
+        env['LDFLAGS'] = '-m64'
+
+    env_args = ['env'] + ['='.join([k, v]) for k, v in env.items()]
+    check_call(env_args + configure_args)
+
+
+def build(jobs):
+    """Builds binutils."""
+    check_call(['make', '-j', str(jobs)])
+
+
+def install_winpthreads(is_windows32, install_dir):
+    """Installs the winpthreads runtime to the Windows bin directory."""
+    lib_name = 'libwinpthread-1.dll'
+    mingw_dir = ndk.paths.android_path(
+        'prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8',
+        'x86_64-w64-mingw32')
+    # Yes, this indeed may be found in bin/ because the executables are the
+    # 64-bit version by default.
+    pthread_dir = 'lib32' if is_windows32 else 'bin'
+    lib_path = os.path.join(mingw_dir, pthread_dir, lib_name)
+
+    lib_install = os.path.join(install_dir, 'bin', lib_name)
+    install_file(lib_path, lib_install)
+
+
+def install(jobs, arch, host, install_dir):
+    """Installs binutils."""
+    check_call(['make', 'install-strip', '-j', str(jobs)])
+
+    if host in ('win', 'win64'):
+        arch_install_dir = os.path.join(
+            install_dir, ndk.abis.arch_to_triple(arch))
+        install_winpthreads(host == 'win', install_dir)
+        install_winpthreads(host == 'win', arch_install_dir)
+
+
+def dist(dist_dir, base_dir, package_name):
+    """Packages binutils for distribution."""
+    has_pbzip2 = ndk.ext.shutil.which('pbzip2') is not None
+    if has_pbzip2:
+        compress_arg = '--use-compress-prog=pbzip2'
+    else:
+        compress_arg = '-j'
+
+    package_path = os.path.join(dist_dir, package_name + '.tar.bz2')
+    cmd = [
+        'tar', compress_arg, '-cf', package_path, '-C', base_dir, package_name,
+    ]
+    subprocess.check_call(cmd)
+
+
+def parse_args():
+    """Parse command line arguments."""
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument(
+        '--arch', choices=ndk.abis.ALL_ARCHITECTURES, required=True)
+    parser.add_argument(
+        '--host', choices=('darwin', 'linux', 'win', 'win64'), required=True)
+
+    parser.add_argument(
+        '--clean', action='store_true',
+        help='Clean the out directory before building.')
+    parser.add_argument(
+        '-j', '--jobs', type=int, default=multiprocessing.cpu_count(),
+        help='Number of jobs to use when building.')
+
+    return parser.parse_args()
+
+
+def main():
+    """Program entry point."""
+    args = parse_args()
+    logging.basicConfig(level=logging.INFO)
+
+    total_timer = ndk.timer.Timer()
+    total_timer.start()
+
+    out_dir = ndk.paths.get_out_dir()
+    dist_dir = ndk.paths.get_dist_dir(out_dir)
+    base_build_dir = os.path.join(
+        out_dir, 'binutils', args.host, args.arch)
+    build_dir = os.path.join(base_build_dir, 'build')
+    package_name = 'binutils-{}-{}'.format(args.arch, args.host)
+    install_dir = os.path.join(base_build_dir, 'install', package_name)
+    binutils_path = os.path.join(THIS_DIR, 'binutils-2.27')
+
+    did_clean = False
+    clean_timer = ndk.timer.Timer()
+    if args.clean and os.path.exists(build_dir):
+        did_clean = True
+        with clean_timer:
+            rmtree(build_dir)
+
+    if not os.path.exists(build_dir):
+        makedirs(build_dir)
+
+    orig_dir = os.getcwd()
+    chdir(build_dir)
+    try:
+        configure_timer = ndk.timer.Timer()
+        with configure_timer:
+            configure(args.arch, args.host, install_dir, binutils_path)
+
+        build_timer = ndk.timer.Timer()
+        with build_timer:
+            build(args.jobs)
+
+        install_timer = ndk.timer.Timer()
+        with install_timer:
+            install(args.jobs, args.arch, args.host, install_dir)
+    finally:
+        chdir(orig_dir)
+
+    package_timer = ndk.timer.Timer()
+    with package_timer:
+        dist(dist_dir, os.path.dirname(install_dir), package_name)
+
+    total_timer.finish()
+
+    if did_clean:
+        print('Clean: {}'.format(clean_timer.duration))
+    print('Configure: {}'.format(configure_timer.duration))
+    print('Build: {}'.format(build_timer.duration))
+    print('Install: {}'.format(install_timer.duration))
+    print('Package: {}'.format(package_timer.duration))
+    print('Total: {}'.format(total_timer.duration))
+
+
+if __name__ == '__main__':
+    main()