[build-script] Perform validation after defaults propagation

utils/build-script

@@ -130,7 +130,7 @@ class HostSpecificConfiguration(object):
                deployment_platform.is_embedded and \
                not deployment_platform.is_simulator:
                 if deployment_platform not in \
-                       invocation.platforms_to_skip_test_host:
+                        invocation.platforms_to_skip_test_host:
                     test_host_only = True
                     test = True
                 else:
@@ -142,7 +142,7 @@ class HostSpecificConfiguration(object):
                 # library, whereas the other targets can build a slightly
                 # smaller subset which is faster to build.
                 if args.build_swift_stdlib_unittest_extra or \
-                       args.validation_test or args.long_test:
+                        args.validation_test or args.long_test:
                     self.swift_stdlib_build_targets.append(
                         "swift-stdlib-" + name)
                 else:
@@ -395,6 +395,18 @@ class BuildScriptInvocation(object):
             args.stdlib_deployment_targets.append(
                 StdlibDeploymentTarget.Android.armv7.name)
 
+        # Infer platform flags from manually-specified configure targets.
+        # This doesn't apply to Darwin platforms, as they are
+        # already configured. No building without the platform flag, though.
+
+        android_tgts = [tgt for tgt in args.stdlib_deployment_targets
+                        if StdlibDeploymentTarget.Android.contains(tgt)]
+        if not args.android and len(android_tgts) > 0:
+            args.android = True
+            args.skip_build_android = True
+
+# ---
+
     def __init__(self, toolchain, args):
         self.toolchain = toolchain
         self.args = args
@@ -1768,12 +1780,12 @@ details of the setups of other systems or automated environments.""")
     if args.cmake is not None:
         toolchain.cmake = args.cmake
 
-    # Validate the arguments.
-    BuildScriptInvocation.validate_arguments(toolchain, args)
-
     # Preprocess the arguments to apply defaults.
     BuildScriptInvocation.apply_default_arguments(toolchain, args)
 
+    # Validate the arguments.
+    BuildScriptInvocation.validate_arguments(toolchain, args)
+
     # Create the build script invocation.
     invocation = BuildScriptInvocation(toolchain, args)
 

utils/swift_build_support/swift_build_support/targets.py

@@ -42,6 +42,16 @@ def supports_benchmark(self):
         # By default, we don't support benchmarks on most platforms.
         return False
 
+    def contains(self, target_name):
+        """
+        Returns True if the given target name belongs to a one of this
+        platform's targets.
+        """
+        for target in self.targets:
+            if target.name == target_name:
+                return True
+        return False
+
 
 class DarwinPlatform(Platform):
     def __init__(self, name, archs, sdk_name=None, is_simulator=False):

utils/swift_build_support/tests/test_targets.py

@@ -18,5 +18,20 @@ def test_is_not_none_on_this_platform(self):
         self.assertIsNotNone(StdlibDeploymentTarget.host_target())
 
 
+class PlatformTargetsTestCase(unittest.TestCase):
+    def test_platform_contains(self):
+        """
+        Checks that Platform.contains(target_name)
+        matches all of its targets' names and rejects non-matching names.
+        """
+        # Pick a few platforms with lots of targets
+        for platform in [StdlibDeploymentTarget.Linux,
+                         StdlibDeploymentTarget.iOS,
+                         StdlibDeploymentTarget.iOSSimulator]:
+            for target in platform.targets:
+                self.assertTrue(platform.contains(target.name))
+            self.assertFalse(platform.contains("fakeCPU-MSDOS"))
+            self.assertFalse(platform.contains("singleTransistor-fakeOS"))
+
 if __name__ == '__main__':
     unittest.main()