[build-script] Add a default-enabled "clean" step for swift-driver and swiftpm products

utils/build-script

@@ -964,6 +964,9 @@ class BuildScriptInvocation(object):
                     toolchain=self.toolchain,
                     source_dir=self.workspace.source_dir(product_source),
                     build_dir=build_dir)
+                if product.should_clean(host_target):
+                    print("--- Cleaning %s ---" % product_name)
+                    product.clean(host_target)
                 if product.should_build(host_target):
                     print("--- Building %s ---" % product_name)
                     product.build(host_target)

utils/build_swift/build_swift/driver_arguments.py

@@ -1008,6 +1008,10 @@ def create_argument_parser():
            help='skip testing Android device targets on the host machine (the '
                 'phone itself)')
 
+    option('--skip-clean-swiftpm', toggle_false('clean_swiftpm'),
+           help='skip cleaning up swiftpm')
+    option('--skip-clean-swift-driver', toggle_false('clean_swift_driver'),
+           help='skip cleaning up Swift driver')
     option('--skip-test-swiftpm', toggle_false('test_swiftpm'),
            help='skip testing swiftpm')
     option('--skip-test-swift-driver', toggle_false('test_swift_driver'),

utils/build_swift/tests/expected_options.py

@@ -205,6 +205,8 @@
         defaults.SWIFT_MAX_PARALLEL_LTO_LINK_JOBS,
     'swift_user_visible_version': defaults.SWIFT_USER_VISIBLE_VERSION,
     'symbols_package': None,
+    'clean_swiftpm': True,
+    'clean_swift_driver': True,
     'test': None,
     'test_android': False,
     'test_android_host': False,
@@ -567,6 +569,8 @@ class BuildScriptImplOption(_BaseOption):
                   dest='build_watchos_device'),
     DisableOption('--skip-build-watchos-simulator',
                   dest='build_watchos_simulator'),
+    DisableOption('--skip-clean-swiftpm', dest='clean_swiftpm'),
+    DisableOption('--skip-clean-swift-driver', dest='clean_swift_driver'),
     DisableOption('--skip-test-android', dest='test_android'),
     DisableOption('--skip-test-android-host', dest='test_android_host'),
     DisableOption('--skip-test-cygwin', dest='test_cygwin'),

utils/swift_build_support/swift_build_support/products/product.py

@@ -78,6 +78,20 @@ def get_dependencies(cls):
         """Return a list of products that this product depends upon"""
         raise NotImplementedError
 
+    def should_clean(self, host_target):
+        """should_clean() -> Bool
+
+        Whether or not this product should be cleaned before being built
+        """
+        return False
+
+    def clean(self, host_target):
+        """clean() -> void
+
+        Perform the clean, for a non-build-script-impl product.
+        """
+        raise NotImplementedError
+
     def should_build(self, host_target):
         """should_build() -> Bool
 

utils/swift_build_support/swift_build_support/products/swiftdriver.py

@@ -47,6 +47,13 @@ def get_dependencies(cls):
                 xctest.XCTest,
                 llbuild.LLBuild]
 
+    def should_clean(self, host_target):
+        return self.args.clean_swift_driver
+
+    def clean(self, host_target):
+        indexstoredb.run_build_script_helper(
+            'clean', host_target, self, self.args)
+
     def build(self, host_target):
         indexstoredb.run_build_script_helper(
             'build', host_target, self, self.args)

utils/swift_build_support/swift_build_support/products/swiftpm.py

@@ -51,6 +51,11 @@ def run_bootstrap_script(self, action, host_target, additional_params=[]):
 
         helper_cmd = [script_path, action]
 
+        if action == 'clean':
+            helper_cmd += ["--build-dir", self.build_dir]
+            shell.call(helper_cmd)
+            return
+
         if self.is_release():
             helper_cmd.append("--release")
 
@@ -94,6 +99,12 @@ def should_test(self, host_target):
     def test(self, host_target):
         self.run_bootstrap_script('test', host_target)
 
+    def should_clean(self, host_target):
+        return self.args.clean_swiftpm
+
+    def clean(self, host_target):
+        self.run_bootstrap_script('clean', host_target)
+
     def should_install(self, host_target):
         return self.args.install_swiftpm