diff --git a/Android.bp b/Android.bp
index 1785342..9952a8f 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,4 +1 @@
-subdirs = [
-    "tests",
-    "build",
-]
+subdirs = ["tests"]
diff --git a/Android.mk b/Android.mk
index 0d4d67f..40c4570 100644
--- a/Android.mk
+++ b/Android.mk
@@ -222,7 +222,6 @@
     plat_and_mapping_sepolicy.cil.sha256 \
     secilc \
     plat_sepolicy_vers.txt \
-    vendor_service_contexts \
 
 # Include precompiled policy, unless told otherwise
 ifneq ($(PRODUCT_PRECOMPILED_SEPOLICY),false)
@@ -234,7 +233,6 @@
 endif
 
 LOCAL_REQUIRED_MODULES += \
-    build_sepolicy \
     vendor_file_contexts \
     vendor_mac_permissions.xml \
     vendor_property_contexts \
@@ -249,6 +247,10 @@
     searchpolicy \
     vndservice_contexts \
 
+ifneq ($(PRODUCT_SEPOLICY_SPLIT),true)
+LOCAL_REQUIRED_MODULES += vendor_service_contexts
+endif
+
 ifneq ($(TARGET_BUILD_VARIANT), user)
 LOCAL_REQUIRED_MODULES += \
     selinux_denial_metadata \
@@ -538,23 +540,31 @@
 	$(transform-policy-to-conf)
 	$(hide) sed '/dontaudit/d' $@ > $@.dontaudit
 
-$(LOCAL_BUILT_MODULE): PRIVATE_POL_CONF := $(vendor_policy.conf)
-$(LOCAL_BUILT_MODULE): PRIVATE_REQD_MASK := $(reqd_policy_mask.cil)
-$(LOCAL_BUILT_MODULE): PRIVATE_BASE_CIL := $(plat_pub_policy.cil)
-$(LOCAL_BUILT_MODULE): PRIVATE_VERS := $(BOARD_SEPOLICY_VERS)
-$(LOCAL_BUILT_MODULE): PRIVATE_DEP_CIL_FILES := $(built_plat_cil) $(built_plat_pub_vers_cil) $(built_mapping_cil)
-$(LOCAL_BUILT_MODULE): PRIVATE_FILTER_CIL := $(built_plat_pub_vers_cil)
-$(LOCAL_BUILT_MODULE): $(HOST_OUT_EXECUTABLES)/build_sepolicy \
-  $(vendor_policy.conf) $(reqd_policy_mask.cil) $(plat_pub_policy.cil) \
+vendor_policy_raw := $(intermediates)/vendor_policy_raw.cil
+$(vendor_policy_raw): PRIVATE_POL_CONF := $(vendor_policy.conf)
+$(vendor_policy_raw): PRIVATE_REQD_MASK := $(reqd_policy_mask.cil)
+$(vendor_policy_raw): $(HOST_OUT_EXECUTABLES)/checkpolicy $(vendor_policy.conf) \
+$(reqd_policy_mask.cil)
+	@mkdir -p $(dir $@)
+	$(hide) $(CHECKPOLICY_ASAN_OPTIONS) $< -C -M -c $(POLICYVERS) -o $@.tmp $(PRIVATE_POL_CONF)
+	$(hide) grep -Fxv -f $(PRIVATE_REQD_MASK) $@.tmp > $@
+
+$(LOCAL_BUILT_MODULE) : PRIVATE_VERS := $(BOARD_SEPOLICY_VERS)
+$(LOCAL_BUILT_MODULE) : PRIVATE_TGT_POL := $(vendor_policy_raw)
+$(LOCAL_BUILT_MODULE) : PRIVATE_DEP_CIL_FILES := $(built_plat_cil) $(built_plat_pub_vers_cil) $(built_mapping_cil)
+$(LOCAL_BUILT_MODULE) : PRIVATE_FILTER_CIL := $(built_plat_pub_vers_cil)
+$(LOCAL_BUILT_MODULE) : $(plat_pub_policy.cil) $(vendor_policy_raw) \
+  $(HOST_OUT_EXECUTABLES)/version_policy $(HOST_OUT_EXECUTABLES)/secilc \
   $(built_plat_cil) $(built_plat_pub_vers_cil) $(built_mapping_cil)
 	@mkdir -p $(dir $@)
-	$(hide) $(HOST_OUT_EXECUTABLES)/build_sepolicy -a $(HOST_OUT_EXECUTABLES) build_cil \
-		-i $(PRIVATE_POL_CONF) -m $(PRIVATE_REQD_MASK) -c $(CHECKPOLICY_ASAN_OPTIONS) \
-		-b $(PRIVATE_BASE_CIL) -d $(PRIVATE_DEP_CIL_FILES) -f $(PRIVATE_FILTER_CIL) \
-		-t $(PRIVATE_VERS) -p $(POLICYVERS) -o $@
+	$(HOST_OUT_EXECUTABLES)/version_policy -b $< -t $(PRIVATE_TGT_POL) -n $(PRIVATE_VERS) -o $@.tmp
+	$(hide) grep -Fxv -f $(PRIVATE_FILTER_CIL) $@.tmp > $@
+	$(hide) $(HOST_OUT_EXECUTABLES)/secilc -m -M true -G -N -c $(POLICYVERS) \
+		$(PRIVATE_DEP_CIL_FILES) $@ -o /dev/null -f /dev/null
 
 built_vendor_cil := $(LOCAL_BUILT_MODULE)
 vendor_policy.conf :=
+vendor_policy_raw :=
 
 #################################
 include $(CLEAR_VARS)
diff --git a/build/Android.bp b/build/Android.bp
deleted file mode 100644
index d3f1fc3..0000000
--- a/build/Android.bp
+++ /dev/null
@@ -1,34 +0,0 @@
-// 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.
-// 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.
-
-python_binary_host {
-  name: "build_sepolicy",
-  srcs: [
-    "build_sepolicy.py",
-    "file_utils.py",
-  ],
-  required: [
-    "checkpolicy",
-    "secilc",
-    "version_policy",
-  ],
-  version: {
-    py2: {
-      enabled: true,
-    },
-    py3: {
-      enabled: false,
-    },
-  },
-}
diff --git a/build/build_sepolicy.py b/build/build_sepolicy.py
deleted file mode 100644
index ff2ff07..0000000
--- a/build/build_sepolicy.py
+++ /dev/null
@@ -1,140 +0,0 @@
-# Copyright 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.
-# 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.
-
-"""Command-line tool to build SEPolicy files."""
-
-import argparse
-import os
-import subprocess
-import sys
-
-import file_utils
-
-
-# All supported commands in this module.
-# For each command, need to add two functions. Take 'build_cil' for example:
-#   - setup_build_cil()
-#     - Sets up command parsers and sets default function to do_build_cil().
-#   - do_build_cil()
-_SUPPORTED_COMMANDS = ('build_cil',)
-
-
-def run_host_command(args, **kwargs):
-    """Runs a host command and prints output."""
-    if kwargs.get('shell'):
-        command_log = args
-    else:
-        command_log = ' '.join(args)  # For args as a sequence.
-
-    try:
-        subprocess.check_call(args, **kwargs)
-    except subprocess.CalledProcessError as err:
-        sys.stderr.write(
-            'build_sepolicy - failed to run command: {!r} (ret:{})\n'.format(
-                command_log, err.returncode))
-        sys.exit(err.returncode)
-
-
-def do_build_cil(args):
-    """Builds a sepolicy CIL (Common Intermediate Language) file.
-
-    This functions invokes some host utils (e.g., secilc, checkpolicy,
-    version_sepolicy) to generate a .cil file.
-
-    Args:
-        args: the parsed command arguments.
-    """
-    # Determines the raw CIL file name.
-    input_file_name = os.path.splitext(args.input_policy_conf)[0]
-    raw_cil_file = input_file_name + '_raw.cil'
-    # Builds the raw CIL.
-    file_utils.make_parent_dirs(raw_cil_file)
-    checkpolicy_cmd = [args.checkpolicy_env]
-    checkpolicy_cmd += [os.path.join(args.android_host_path, 'checkpolicy'),
-                        '-C', '-M', '-c', args.policy_vers,
-                        '-o', raw_cil_file, args.input_policy_conf]
-    # Using shell=True to setup args.checkpolicy_env variables.
-    run_host_command(' '.join(checkpolicy_cmd), shell=True)
-    file_utils.filter_out([args.reqd_mask], raw_cil_file)
-
-    # Builds the output CIL by versioning the above raw CIL.
-    output_file = args.output_cil
-    if output_file is None:
-        output_file = input_file_name + '.cil'
-    file_utils.make_parent_dirs(output_file)
-
-    run_host_command([os.path.join(args.android_host_path, 'version_policy'),
-                      '-b', args.base_policy, '-t', raw_cil_file,
-                      '-n', args.treble_sepolicy_vers, '-o', output_file])
-    if args.filter_out_files:
-        file_utils.filter_out(args.filter_out_files, output_file)
-
-    # Tests that the output file can be merged with the given CILs.
-    if args.dependent_cils:
-        merge_cmd = [os.path.join(args.android_host_path, 'secilc'),
-                     '-m', '-M', 'true', '-G', '-N', '-c', args.policy_vers]
-        merge_cmd += args.dependent_cils      # the give CILs to merge
-        merge_cmd += [output_file, '-o', '/dev/null', '-f', '/dev/null']
-        run_host_command(merge_cmd)
-
-
-def setup_build_cil(subparsers):
-    """Sets up command args for 'build_cil' command."""
-
-    # Required arguments.
-    parser = subparsers.add_parser('build_cil', help='build CIL files')
-    parser.add_argument('-i', '--input_policy_conf', required=True,
-                        help='source policy.conf')
-    parser.add_argument('-m', '--reqd_mask', required=True,
-                        help='the bare minimum policy.conf to use checkpolicy')
-    parser.add_argument('-b', '--base_policy', required=True,
-                        help='base policy for versioning')
-    parser.add_argument('-t', '--treble_sepolicy_vers', required=True,
-                        help='the version number to use for Treble-OTA')
-    parser.add_argument('-p', '--policy_vers', required=True,
-                        help='SELinux policy version')
-
-    # Optional arguments.
-    parser.add_argument('-c', '--checkpolicy_env',
-                        help='environment variables passed to checkpolicy')
-    parser.add_argument('-f', '--filter_out_files', nargs='+',
-                        help='the pattern files to filter out the output cil')
-    parser.add_argument('-d', '--dependent_cils', nargs='+',
-                        help=('check the output file can be merged with '
-                              'the dependent cil files'))
-    parser.add_argument('-o', '--output_cil', help='the output cil file')
-
-    # The function that performs the actual works.
-    parser.set_defaults(func=do_build_cil)
-
-
-def run(argv):
-    """Sets up command parser and execuates sub-command."""
-    parser = argparse.ArgumentParser()
-
-    # Adds top-level arguments.
-    parser.add_argument('-a', '--android_host_path', default='',
-                        help='a path to host out executables')
-
-    # Adds subparsers for each COMMAND.
-    subparsers = parser.add_subparsers(title='COMMAND')
-    for command in _SUPPORTED_COMMANDS:
-        globals()['setup_' + command](subparsers)
-
-    args = parser.parse_args(argv[1:])
-    args.func(args)
-
-
-if __name__ == '__main__':
-    run(sys.argv)
diff --git a/build/file_utils.py b/build/file_utils.py
deleted file mode 100644
index 1559a9b..0000000
--- a/build/file_utils.py
+++ /dev/null
@@ -1,49 +0,0 @@
-# Copyright 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.
-# 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.
-
-"""File-related utilities."""
-
-
-import os
-import shutil
-import tempfile
-
-
-def make_parent_dirs(file_path):
-    """Creates parent directories for the file_path."""
-    if os.path.exists(file_path):
-        return
-
-    parent_dir = os.path.dirname(file_path)
-    if parent_dir and not os.path.exists(parent_dir):
-        os.makedirs(parent_dir)
-
-
-def filter_out(pattern_files, input_file):
-    """"Removes lines in input_file that match any line in pattern_files."""
-
-    # Prepares patterns.
-    patterns = []
-    for f in pattern_files:
-        patterns.extend(open(f).readlines())
-
-    # Copy lines that are not in the pattern.
-    tmp_output = tempfile.NamedTemporaryFile()
-    with open(input_file, 'r') as in_file:
-        tmp_output.writelines(line for line in in_file.readlines()
-                              if line not in patterns)
-        tmp_output.flush()
-
-    # Replaces the input_file.
-    shutil.copyfile(tmp_output.name, input_file)