[cxx-interop] Provide a support header for common attributes, etc.

Author: zoecarver

lib/ClangImporter/CMakeLists.txt

@@ -42,3 +42,24 @@ add_dependencies(swiftClangImporter
   ${CLANG_TABLEGEN_TARGETS})
 
 set_swift_llvm_is_available(swiftClangImporter)
+
+# Mark - copy "cxx-interop.h" into the local include directory and install it
+# into the compiler toolchain.
+set(SWIFTINC_DIR
+    "${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/include/swift")
+
+add_custom_command(
+    OUTPUT "${SWIFTINC_DIR}/cxx-interop.h"
+    COMMAND "${CMAKE_COMMAND}" "-E" "copy" "${CMAKE_CURRENT_SOURCE_DIR}/cxx-interop.h" "${SWIFTINC_DIR}")
+
+add_custom_target("copy_cxxInterop_support_header"
+    DEPENDS "${SWIFTINC_DIR}/cxx-interop.h"
+    COMMENT "Copying C++ interop support header to ${SWIFTINC_DIR}")
+
+swift_install_in_component(FILES "${CMAKE_CURRENT_SOURCE_DIR}/cxx-interop.h"
+                           TARGET ${SWIFT_CLANG_RESOURCE_DIR_SYMLINK_INSTALL_TARGET}
+                           DESTINATION "include/swift"
+                           COMPONENT compiler)
+
+add_dependencies(swiftClangImporter
+  "copy_cxxInterop_support_header")

lib/ClangImporter/cxx-interop.h

@@ -0,0 +1,31 @@
+//===--- cxx-interop.h - C++ and Swift Interop ------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides common utilities and annotations that are useful for C++
+// codebases that interoperate with Swift.
+//
+//===----------------------------------------------------------------------===//
+#ifndef SWIFT_CLANGIMPORTER_CXX_INTEROP_H
+#define SWIFT_CLANGIMPORTER_CXX_INTEROP_H
+
+#define SELF_CONTAINED __attribute__((swift_attr("import_owned")))
+#define SAFE_TO_IMPORT __attribute__((swift_attr("import_unsafe")))
+
+#define _CXX_INTEROP_STRINGIFY(_x) #_x
+#define REFERENCE(_retain, _release)                                           \
+  __attribute__((swift_attr("import_reference")))                              \
+  __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(retain:_retain))))          \
+  __attribute__((swift_attr(_CXX_INTEROP_STRINGIFY(release:_release))))
+
+#define SWIFT_NAME(_name) __attribute__((swift_name(#_name)))
+
+#endif // SWIFT_CLANGIMPORTER_CXX_INTEROP_H