Add support for watchOS in swift_library

--
MOS_MIGRATED_REVID=131631222

3 files changed, 63 insertions, 8 deletions

diff --git a/src/test/shell/bazel/bazel_apple_test.sh b/src/test/shell/bazel/bazel_apple_test.sh
index 5f56934bfc..8495c15dba 100755
--- a/src/test/shell/bazel/bazel_apple_test.sh
+++ b/src/test/shell/bazel/bazel_apple_test.sh
@@ -517,4 +517,34 @@ EOF
       //ios:swift_lib >$TEST_log 2>&1 || fail "should build"
 }
 
+function test_apple_watch_with_swift() {
+  make_app
+
+  cat >ios/watchapp.swift <<EOF
+  import WatchKit
+  class ExtensionDelegate: NSObject, WKExtensionDelegate {
+    func applicationDidFinishLaunching() {}
+  }
+EOF
+
+  cat >ios/BUILD <<EOF
+load("//tools/build_defs/apple:swift.bzl", "swift_library")
+
+swift_library(name = "WatchModule",
+              srcs = ["watchapp.swift"])
+
+apple_binary(name = "bin",
+             deps = [":WatchModule"],
+             platform_type = "watchos")
+
+apple_watch2_extension(
+    name = "WatchExtension",
+    app_bundle_id = "com.google.app.watchkit",
+    app_name = "WatchApp",
+    binary = ":bin",
+    ext_bundle_id = "com.google.app.extension",
+)
+EOF
+}
+
 run_suite "apple_tests"
diff --git a/tools/build_defs/apple/shared.bzl b/tools/build_defs/apple/shared.bzl
index 976911b177..05d96ceb91 100644
--- a/tools/build_defs/apple/shared.bzl
+++ b/tools/build_defs/apple/shared.bzl
@@ -65,10 +65,16 @@ def xcrun_action(ctx, **kw):
   This method takes the same keyword arguments as ctx.action, however you don't
   need to specify the executable.
   """
-  platform = ctx.fragments.apple.ios_cpu_platform()
+  if hasattr(ctx.fragments.apple, "single_arch_platform"):
+    platform = ctx.fragments.apple.single_arch_platform
+  else:
+    # TODO(dmishe): Remove this branch when single_arch_platform is available
+    # by default.
+    platform = ctx.fragments.apple.ios_cpu_platform()
+
   action_env = ctx.fragments.apple.target_apple_env(platform) \
       + ctx.fragments.apple.apple_host_system_env()
-  env = kw.get('env', {})
+  env = kw.get("env", {})
   kw['env'] = env + action_env
 
   apple_action(ctx, executable=ctx.executable._xcrunwrapper, **kw)
diff --git a/tools/build_defs/apple/swift.bzl b/tools/build_defs/apple/swift.bzl
index 9f0889c432..4a6f443518 100644
--- a/tools/build_defs/apple/swift.bzl
+++ b/tools/build_defs/apple/swift.bzl
@@ -29,9 +29,18 @@ def _intersperse(separator, iterable):
 
   return result
 
-def _swift_target(cpu, sdk_version):
+def _swift_target(cpu, platform, sdk_version):
   """Returns a target triplet for Swift compiler."""
-  return "%s-apple-ios%s" % (cpu, sdk_version)
+  # TODO(dmishe): Use PlatformType object when available.
+  platform_string = None
+  if str(platform).startswith("IOS_"):
+    platform_string = "ios"
+  elif str(platform).startswith("WATCHOS_"):
+    platform_string = "watchos"
+  else:
+    fail("Platform %s is not supported")
+
+  return "%s-apple-%s%s" % (cpu, platform_string, sdk_version)
 
 def _swift_compilation_mode_flags(ctx):
   """Returns additional swiftc flags for the current compilation mode."""
@@ -61,10 +70,20 @@ def _module_name(ctx):
 def _swift_library_impl(ctx):
   """Implementation for swift_library Skylark rule."""
   # TODO(b/29772303): Assert xcode version.
-  cpu = ctx.fragments.apple.ios_cpu()
-  platform = ctx.fragments.apple.ios_cpu_platform()
-  sdk_version = ctx.fragments.apple.sdk_version_for_platform(platform)
-  target = _swift_target(cpu, sdk_version)
+  apple_fm = ctx.fragments.apple
+
+  if (hasattr(apple_fm, "single_arch_platform")
+      and hasattr(apple_fm, "single_arch_cpu")):
+    cpu = apple_fm.single_arch_cpu
+    platform = apple_fm.single_arch_platform
+  else:
+    # TODO(dmishe): Remove this branch when single_arch_platform is available
+    # by default.
+    cpu = apple_fm.ios_cpu()
+    platform = apple_fm.ios_cpu_platform()
+
+  sdk_version = apple_fm.sdk_version_for_platform(platform)
+  target = _swift_target(cpu, platform, sdk_version)
   apple_toolchain = apple_common.apple_toolchain()
 
   module_name = ctx.attr.module_name or _module_name(ctx)