[build-script] Add support for building, installing, and testing swift-driver

Add build-script command-line options for building, installing, and
testing swift-driver:
* `--swift-driver` will build the Swift driver. If testing is enabled,
  it will be tested as well
* `--install-swift-driver` will install the `swift-driver` and
  `swift-help` executables in the toolchain.
* `--skip-test-swift-driver` will disable testing of the Swift driver
when other tests are being run.

The Swift driver depends on SwiftPM to build; it is recommended that
you use `--infer` to get the appropriate dependencies built.

Note that this option does not yet replace the existing Swift driver
executables (`swiftc`, `swift`) with the new driver, nor does it
install the SwiftDriver library for use elsewhere.

Author: DougGregor

utils/build-script

@@ -862,6 +862,8 @@ class BuildScriptInvocation(object):
         product_classes = []
         if self.args.build_swiftpm:
             product_classes.append(products.SwiftPM)
+        if self.args.build_swift_driver:
+            product_classes.append(products.SwiftDriver)
         if self.args.build_swiftsyntax:
             product_classes.append(products.SwiftSyntax)
         if self.args.build_skstresstester:

utils/build_swift/build_swift/driver_arguments.py

@@ -184,6 +184,7 @@ def _apply_default_arguments(args):
         args.test_watchos = False
         args.test_android = False
         args.test_swiftpm = False
+        args.test_swift_driver = False
         args.test_swiftsyntax = False
         args.test_indexstoredb = False
         args.test_sourcekitlsp = False
@@ -574,6 +575,9 @@ def create_argument_parser():
     option(['--swiftevolve'], store_true('build_swiftevolve'),
            help='build the swift-evolve tool')
 
+    option(['--swift-driver'], toggle_true('build_swift_driver'),
+           help='build swift-driver')
+
     option(['--indexstore-db'], toggle_true('build_indexstoredb'),
            help='build IndexStoreDB')
     option('--test-indexstore-db-sanitize-all',
@@ -596,6 +600,8 @@ def create_argument_parser():
            help='install SourceKitLSP')
     option(['--install-skstresstester'], toggle_true('install_skstresstester'),
            help='install the SourceKit stress tester')
+    option(['--install-swift-driver'], toggle_true('install_swift_driver'),
+           help='install new Swift driver')
     option(['--install-swiftevolve'], toggle_true('install_swiftevolve'),
            help='install SwiftEvolve')
     option(['--toolchain-benchmarks'],
@@ -1009,6 +1015,8 @@ def create_argument_parser():
 
     option('--skip-test-swiftpm', toggle_false('test_swiftpm'),
            help='skip testing swiftpm')
+    option('--skip-test-swiftdriver', toggle_false('test_swift_driver'),
+           help='skip testing Swift driver')
     option('--skip-test-swiftsyntax', toggle_false('test_swiftsyntax'),
            help='skip testing SwiftSyntax')
     option('--skip-test-indexstore-db', toggle_false('test_indexstoredb'),

utils/swift_build_support/swift_build_support/products/__init__.py

@@ -26,6 +26,7 @@
 from .skstresstester import SKStressTester
 from .sourcekitlsp import SourceKitLSP
 from .swift import Swift
+from .swiftdriver import SwiftDriver
 from .swiftevolve import SwiftEvolve
 from .swiftinspect import SwiftInspect
 from .swiftpm import SwiftPM

utils/swift_build_support/swift_build_support/products/swiftdriver.py

@@ -0,0 +1,72 @@
+# swift_build_support/products/swiftdriver.py -------------------*- python -*-
+#
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+#
+# ----------------------------------------------------------------------------
+
+import os
+
+from . import cmark
+from . import foundation
+from . import indexstoredb
+from . import libcxx
+from . import libdispatch
+from . import libicu
+from . import llbuild
+from . import llvm
+from . import product
+from . import swift
+from . import xctest
+
+from .. import shell
+from .. import targets
+
+class SwiftDriver(product.Product):
+    @classmethod
+    def product_source_name(cls):
+        return "swift-driver"
+
+    @classmethod
+    def is_build_script_impl_product(cls):
+        return False
+
+    def should_build(self, host_target):
+        return self.args.build_swift_driver
+
+    @classmethod
+    def get_dependencies(cls):
+        return [cmark.CMark,
+                llvm.LLVM,
+                libcxx.LibCXX,
+                libicu.LibICU,
+                swift.Swift,
+                libdispatch.LibDispatch,
+                foundation.Foundation,
+                xctest.XCTest,
+                llbuild.LLBuild]
+
+    def build(self, host_target):
+        indexstoredb.run_build_script_helper(
+            'build', host_target, self, self.args)
+
+    def should_test(self, host_target):
+        return self.args.test_swift_driver
+
+    def test(self, host_target):
+        indexstoredb.run_build_script_helper(
+            'test', host_target, self, self.args,
+            self.args.test_sourcekitlsp_sanitize_all)
+
+    def should_install(self, host_target):
+        return self.args.install_swift_driver
+
+    def install(self, host_target):
+        indexstoredb.run_build_script_helper(
+            'install', host_target, self, self.args)
+