[cxx-interop] add a build setting to control whether the <swift/bridg…

CMakeLists.txt

@@ -614,6 +614,10 @@ option(SWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP
   "Enable experimental C++ interop modules"
   FALSE)
 
+option(SWIFT_ENABLE_CXX_INTEROP_SWIFT_BRIDGING_HEADER
+  "Install the <swift/bridging> C++ interoperability header alongside compiler"
+  TRUE)
+
 option(SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED
   "Enable experimental distributed actors and functions"
   FALSE)

lib/ClangImporter/CMakeLists.txt

@@ -43,25 +43,27 @@ add_dependencies(swiftClangImporter
 
 set_swift_llvm_is_available(swiftClangImporter)
 
-# Mark - copy "bridging" (support header) into the local include directory and
-# install it into the compiler toolchain.
-set(SWIFTINC_DIR
-    "${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/include/swift")
+if(SWIFT_ENABLE_CXX_INTEROP_SWIFT_BRIDGING_HEADER)
+  # Mark - copy "bridging" (support header) 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 "${SWIFTINC_DIR}/bridging"
-    DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/bridging"
-    COMMAND "${CMAKE_COMMAND}" "-E" "copy" "${CMAKE_CURRENT_SOURCE_DIR}/bridging" "${SWIFTINC_DIR}")
+  add_custom_command(
+      OUTPUT "${SWIFTINC_DIR}/bridging"
+      DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/bridging"
+      COMMAND "${CMAKE_COMMAND}" "-E" "copy" "${CMAKE_CURRENT_SOURCE_DIR}/bridging" "${SWIFTINC_DIR}")
 
-add_custom_target("copy_cxxInterop_support_header"
-    DEPENDS "${SWIFTINC_DIR}/bridging"
-    COMMENT "Copying C++ interop support header to ${SWIFTINC_DIR}")
+  add_custom_target("copy_cxxInterop_support_header"
+      DEPENDS "${SWIFTINC_DIR}/bridging"
+      COMMENT "Copying C++ interop support header to ${SWIFTINC_DIR}")
 
-swift_install_in_component(FILES
-                           "${CMAKE_CURRENT_SOURCE_DIR}/bridging"
-                           "${CMAKE_CURRENT_SOURCE_DIR}/module.modulemap"
-                           DESTINATION "include/swift"
-                           COMPONENT compiler)
+  swift_install_in_component(FILES
+                             "${CMAKE_CURRENT_SOURCE_DIR}/bridging"
+                             "${CMAKE_CURRENT_SOURCE_DIR}/module.modulemap"
+                             DESTINATION "include/swift"
+                             COMPONENT compiler)
 
-add_dependencies(swiftClangImporter
-  "copy_cxxInterop_support_header")
+  add_dependencies(swiftClangImporter
+      "copy_cxxInterop_support_header")
+endif()

utils/build_swift/build_swift/driver_arguments.py

@@ -1319,6 +1319,10 @@ def create_argument_parser():
            default=True,
            help='Enable experimental C++ interop.')
 
+    option('--enable-cxx-interop-swift-bridging-header', toggle_true,
+           default=True,
+           help='Ship the <swift/bridging> header for C++ interop')
+
     option('--enable-experimental-distributed', toggle_true,
            default=True,
            help='Enable experimental Swift distributed actors.')

utils/build_swift/tests/expected_options.py

@@ -161,6 +161,7 @@
     'enable_experimental_differentiable_programming': True,
     'enable_experimental_concurrency': True,
     'enable_experimental_cxx_interop': True,
+    'enable_cxx_interop_swift_bridging_header': True,
     'enable_experimental_distributed': True,
     'enable_experimental_string_processing': True,
     'enable_experimental_observation': True,
@@ -579,6 +580,7 @@ class BuildScriptImplOption(_BaseOption):
     EnableOption('--enable-experimental-differentiable-programming'),
     EnableOption('--enable-experimental-concurrency'),
     EnableOption('--enable-experimental-cxx-interop'),
+    EnableOption('--enable-cxx-interop-swift-bridging-header'),
     EnableOption('--enable-experimental-distributed'),
     EnableOption('--enable-experimental-string-processing'),
     EnableOption('--enable-experimental-observation'),

utils/swift_build_support/swift_build_support/products/swift.py

@@ -52,8 +52,9 @@ def __init__(self, args, toolchain, source_dir, build_dir):
         # Add experimental concurrency flag.
         self.cmake_options.extend(self._enable_experimental_concurrency)
 
-        # Add experimental cxx interop flag.
+        # Add experimental cxx interop flags.
         self.cmake_options.extend(self._enable_experimental_cxx_interop)
+        self.cmake_options.extend(self._enable_cxx_interop_swift_bridging_header)
 
         # Add experimental distributed flag.
         self.cmake_options.extend(self._enable_experimental_distributed)
@@ -176,6 +177,11 @@ def _enable_experimental_cxx_interop(self):
         return [('SWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP:BOOL',
                  self.args.enable_experimental_cxx_interop)]
 
+    @property
+    def _enable_cxx_interop_swift_bridging_header(self):
+        return [('SWIFT_ENABLE_CXX_INTEROP_SWIFT_BRIDGING_HEADER:BOOL',
+                 self.args.enable_cxx_interop_swift_bridging_header)]
+
     @property
     def _enable_experimental_distributed(self):
         return [('SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED:BOOL',

utils/swift_build_support/tests/products/test_swift.py

@@ -56,6 +56,7 @@ def setUp(self):
             enable_experimental_differentiable_programming=False,
             enable_experimental_concurrency=False,
             enable_experimental_cxx_interop=False,
+            enable_cxx_interop_swift_bridging_header=False,
             enable_experimental_distributed=False,
             enable_experimental_observation=False,
             swift_enable_backtracing=False,
@@ -98,6 +99,7 @@ def test_by_default_no_cmake_options(self):
             '-DSWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP:BOOL=FALSE',
+            '-DSWIFT_ENABLE_CXX_INTEROP_SWIFT_BRIDGING_HEADER:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_OBSERVATION:BOOL=FALSE',
             '-DSWIFT_ENABLE_BACKTRACING:BOOL=FALSE',
@@ -124,6 +126,7 @@ def test_swift_runtime_tsan(self):
             '-DSWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP:BOOL=FALSE',
+            '-DSWIFT_ENABLE_CXX_INTEROP_SWIFT_BRIDGING_HEADER:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_OBSERVATION:BOOL=FALSE',
             '-DSWIFT_ENABLE_BACKTRACING:BOOL=FALSE',
@@ -370,6 +373,18 @@ def test_experimental_cxx_interop_flags(self):
             [option for option in swift.cmake_options
              if 'DSWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP' in option])
 
+    def test_experimental_cxx_interop_bridging_header_flags(self):
+        self.args.enable_cxx_interop_swift_bridging_header = True
+        swift = Swift(
+            args=self.args,
+            toolchain=self.toolchain,
+            source_dir='/path/to/src',
+            build_dir='/path/to/build')
+        self.assertEqual(
+            ['-DSWIFT_ENABLE_CXX_INTEROP_SWIFT_BRIDGING_HEADER:BOOL=TRUE'],
+            [option for option in swift.cmake_options
+             if 'DSWIFT_ENABLE_CXX_INTEROP_SWIFT_BRIDGING_HEADER' in option])
+
     def test_experimental_distributed_flags(self):
         self.args.enable_experimental_distributed = True
         swift = Swift(