diff --git a/util/generate_build_files.py b/util/generate_build_files.py
new file mode 100644
index 00000000..94de5460
--- /dev/null
+++ b/util/generate_build_files.py
@@ -0,0 +1,341 @@
+# Copyright (c) 2015, Google Inc.
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+"""Enumerates the BoringSSL source in src/ and either generates two gypi files
+  (boringssl.gypi and boringssl_tests.gypi) for Chromium, or generates
+  source-list files for Android."""
+
+import os
+import subprocess
+import sys
+
+
+# OS_ARCH_COMBOS maps from OS and platform to the OpenSSL assembly "style" for
+# that platform and the extension used by asm files.
+OS_ARCH_COMBOS = [
+    ('linux', 'arm', 'linux32', [], 'S'),
+    ('linux', 'aarch64', 'linux64', [], 'S'),
+    ('linux', 'x86', 'elf', ['-fPIC', '-DOPENSSL_IA32_SSE2'], 'S'),
+    ('linux', 'x86_64', 'elf', [], 'S'),
+    ('mac', 'x86', 'macosx', ['-fPIC', '-DOPENSSL_IA32_SSE2'], 'S'),
+    ('mac', 'x86_64', 'macosx', [], 'S'),
+    ('win', 'x86', 'win32n', ['-DOPENSSL_IA32_SSE2'], 'asm'),
+    ('win', 'x86_64', 'nasm', [], 'asm'),
+]
+
+# NON_PERL_FILES enumerates assembly files that are not processed by the
+# perlasm system.
+NON_PERL_FILES = {
+    ('linux', 'arm'): [
+        'src/crypto/poly1305/poly1305_arm_asm.S',
+        'src/crypto/chacha/chacha_vec_arm.S',
+        'src/crypto/cpu-arm-asm.S',
+    ],
+}
+
+
+class Chromium(object):
+
+  def __init__(self):
+    self.header = \
+"""# Copyright (c) 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# This file is created by generate_build_files.py. Do not edit manually.
+
+"""
+
+  def PrintVariableSection(self, out, name, files):
+    out.write('    \'%s\': [\n' % name)
+    for f in sorted(files):
+      out.write('      \'%s\',\n' % f)
+    out.write('    ],\n')
+
+  def WriteFiles(self, files, asm_outputs):
+    with open('boringssl.gypi', 'w+') as gypi:
+      gypi.write(self.header + '{\n  \'variables\': {\n')
+
+      self.PrintVariableSection(
+          gypi, 'boringssl_lib_sources', files['crypto'] + files['ssl'])
+
+      for ((osname, arch), asm_files) in asm_outputs:
+        self.PrintVariableSection(gypi, 'boringssl_%s_%s_sources' %
+                                  (osname, arch), asm_files)
+
+      gypi.write('  }\n}\n')
+
+    with open('boringssl_tests.gypi', 'w+') as test_gypi:
+      test_gypi.write(self.header + '{\n  \'targets\': [\n')
+
+      test_names = []
+      for test in sorted(files['test']):
+        test_name = 'boringssl_%s' % os.path.splitext(os.path.basename(test))[0]
+        test_gypi.write("""    {
+      'target_name': '%s',
+      'type': 'executable',
+      'dependencies': [
+        'boringssl.gyp:boringssl',
+      ],
+      'sources': [
+        '%s',
+      ],
+      # TODO(davidben): Fix size_t truncations in BoringSSL.
+      # https://crbug.com/429039
+      'msvs_disabled_warnings': [ 4267, ],
+    },\n""" % (test_name, test))
+        test_names.append(test_name)
+
+      test_names.sort()
+
+      test_gypi.write("""  ],
+  'variables': {
+    'boringssl_test_targets': [\n""")
+
+      for test in test_names:
+        test_gypi.write("""      '%s',\n""" % test)
+
+      test_gypi.write('    ],\n  }\n}\n')
+
+
+class Android(object):
+
+  def __init__(self):
+    self.header = \
+"""# Copyright (C) 2015 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.
+
+"""
+
+  def PrintVariableSection(self, out, name, files):
+    out.write('%s := \\\n' % name)
+    for f in sorted(files):
+      out.write('  %s\\\n' % f)
+    out.write('\n')
+
+  def WriteFiles(self, files, asm_outputs):
+    with open('sources.mk', 'w+') as makefile:
+      makefile.write(self.header)
+
+      files['crypto'].append('android_compat_hacks.c')
+      files['crypto'].append('android_compat_keywrap.c')
+      self.PrintVariableSection(makefile, 'crypto_sources', files['crypto'])
+      self.PrintVariableSection(makefile, 'ssl_sources', files['ssl'])
+      self.PrintVariableSection(makefile, 'tool_sources', files['tool'])
+
+      for ((osname, arch), asm_files) in asm_outputs:
+        self.PrintVariableSection(
+            makefile, '%s_%s_sources' % (osname, arch), asm_files)
+
+
+def FindCMakeFiles(directory):
+  """Returns list of all CMakeLists.txt files recursively in directory."""
+  cmakefiles = []
+
+  for (path, _, filenames) in os.walk(directory):
+    for filename in filenames:
+      if filename == 'CMakeLists.txt':
+        cmakefiles.append(os.path.join(path, filename))
+
+  return cmakefiles
+
+
+def NoTests(dent, is_dir):
+  """Filter function that can be passed to FindCFiles in order to remove test
+  sources."""
+  if is_dir:
+    return dent != 'test'
+  return 'test.' not in dent and not dent.startswith('example_')
+
+
+def OnlyTests(dent, is_dir):
+  """Filter function that can be passed to FindCFiles in order to remove
+  non-test sources."""
+  if is_dir:
+    return True
+  return '_test.' in dent or dent.startswith('example_')
+
+
+def FindCFiles(directory, filter_func):
+  """Recurses through directory and returns a list of paths to all the C source
+  files that pass filter_func."""
+  cfiles = []
+
+  for (path, dirnames, filenames) in os.walk(directory):
+    for filename in filenames:
+      if not filename.endswith('.c') and not filename.endswith('.cc'):
+        continue
+      if not filter_func(filename, False):
+        continue
+      cfiles.append(os.path.join(path, filename))
+
+    for (i, dirname) in enumerate(dirnames):
+      if not filter_func(dirname, True):
+        del dirnames[i]
+
+  return cfiles
+
+
+def ExtractPerlAsmFromCMakeFile(cmakefile):
+  """Parses the contents of the CMakeLists.txt file passed as an argument and
+  returns a list of all the perlasm() directives found in the file."""
+  perlasms = []
+  with open(cmakefile) as f:
+    for line in f:
+      line = line.strip()
+      if not line.startswith('perlasm('):
+        continue
+      if not line.endswith(')'):
+        raise ValueError('Bad perlasm line in %s' % cmakefile)
+      # Remove "perlasm(" from start and ")" from end
+      params = line[8:-1].split()
+      if len(params) < 2:
+        raise ValueError('Bad perlasm line in %s' % cmakefile)
+      perlasms.append({
+          'extra_args': params[2:],
+          'input': os.path.join(os.path.dirname(cmakefile), params[1]),
+          'output': os.path.join(os.path.dirname(cmakefile), params[0]),
+      })
+
+  return perlasms
+
+
+def ReadPerlAsmOperations():
+  """Returns a list of all perlasm() directives found in CMake config files in
+  src/."""
+  perlasms = []
+  cmakefiles = FindCMakeFiles('src')
+
+  for cmakefile in cmakefiles:
+    perlasms.extend(ExtractPerlAsmFromCMakeFile(cmakefile))
+
+  return perlasms
+
+
+def PerlAsm(output_filename, input_filename, perlasm_style, extra_args):
+  """Runs the a perlasm script and puts the output into output_filename."""
+  base_dir = os.path.dirname(output_filename)
+  if not os.path.isdir(base_dir):
+    os.makedirs(base_dir)
+  output = subprocess.check_output(
+      ['perl', input_filename, perlasm_style] + extra_args)
+  with open(output_filename, 'w+') as out_file:
+    out_file.write(output)
+
+
+def ArchForAsmFilename(filename):
+  """Returns the architectures that a given asm file should be compiled for
+  based on substrings in the filename."""
+
+  if 'x86_64' in filename or 'avx2' in filename:
+    return ['x86_64']
+  elif ('x86' in filename and 'x86_64' not in filename) or '586' in filename:
+    return ['x86']
+  elif 'armx' in filename:
+    return ['arm', 'aarch64']
+  elif 'armv8' in filename:
+    return ['aarch64']
+  elif 'arm' in filename:
+    return ['arm']
+  else:
+    raise ValueError('Unknown arch for asm filename: ' + filename)
+
+
+def WriteAsmFiles(perlasms):
+  """Generates asm files from perlasm directives for each supported OS x
+  platform combination."""
+  asmfiles = {}
+
+  for osarch in OS_ARCH_COMBOS:
+    (osname, arch, perlasm_style, extra_args, asm_ext) = osarch
+    key = (osname, arch)
+    outDir = '%s-%s' % key
+
+    for perlasm in perlasms:
+      filename = os.path.basename(perlasm['input'])
+      output = perlasm['output']
+      if not output.startswith('src'):
+        raise ValueError('output missing src: %s' % output)
+      output = os.path.join(outDir, output[4:])
+      output = output.replace('${ASM_EXT}', asm_ext)
+
+      if arch in ArchForAsmFilename(filename):
+        PerlAsm(output, perlasm['input'], perlasm_style,
+                perlasm['extra_args'] + extra_args)
+        asmfiles.setdefault(key, []).append(output)
+
+  for (key, non_perl_asm_files) in NON_PERL_FILES.iteritems():
+    asmfiles.setdefault(key, []).extend(non_perl_asm_files)
+
+  return asmfiles
+
+
+def main(platform):
+  crypto_c_files = FindCFiles(os.path.join('src', 'crypto'), NoTests)
+  ssl_c_files = FindCFiles(os.path.join('src', 'ssl'), NoTests)
+  tool_cc_files = FindCFiles(os.path.join('src', 'tool'), NoTests)
+
+  # Generate err_data.c
+  with open('err_data.c', 'w+') as err_data:
+    subprocess.check_call(['go', 'run', 'err_data_generate.go'],
+                          cwd=os.path.join('src', 'crypto', 'err'),
+                          stdout=err_data)
+  crypto_c_files.append('err_data.c')
+
+  test_c_files = FindCFiles(os.path.join('src', 'crypto'), OnlyTests)
+  test_c_files += FindCFiles(os.path.join('src', 'ssl'), OnlyTests)
+
+  files = {
+      'crypto': crypto_c_files,
+      'ssl': ssl_c_files,
+      'tool': tool_cc_files,
+      'test': test_c_files,
+  }
+
+  asm_outputs = sorted(WriteAsmFiles(ReadPerlAsmOperations()).iteritems())
+
+  platform.WriteFiles(files, asm_outputs)
+
+  return 0
+
+
+def Usage():
+  print 'Usage: python %s [chromium|android]' % sys.argv[0]
+  sys.exit(1)
+
+
+if __name__ == '__main__':
+  if len(sys.argv) != 2:
+    Usage()
+
+  platform = None
+  if sys.argv[1] == 'chromium':
+    platform = Chromium()
+  elif sys.argv[1] == 'android':
+    platform = Android()
+  else:
+    Usage()
+
+  sys.exit(main(platform))