build: enable control over the C++ interop modules

Treat the C++ interop modules similar to the Concurrency and
StringProcessing modules, enabled through a top-level global flag.  The
flag now enables disabling the C++ interop modules when the standard
library is built.

Based on the original work by Egor Zhdan!

Author: compnerd

CMakeLists.txt

@@ -605,6 +605,10 @@ option(SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY
   "Enable build of the Swift concurrency module"
   FALSE)
 
+option(SWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP
+  "Enable experimental C++ interop modules"
+  FALSE)
+
 option(SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED
   "Enable experimental distributed actors and functions"
   FALSE)

stdlib/public/CMakeLists.txt

@@ -65,7 +65,9 @@ endif()
 
 add_subdirectory(SwiftShims/swift/shims)
 add_subdirectory(CommandLineSupport)
-add_subdirectory(Cxx)
+if(SWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP)
+  add_subdirectory(Cxx)
+endif()
 add_subdirectory(Threading)
 
 # This static library is shared across swiftCore and swiftRemoteInspection

utils/build-windows-toolchain.bat

@@ -212,6 +212,7 @@ cmake ^
   -D LLVM_VERSION_SUFFIX="" ^
 
   -D SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY=YES ^
+  -D SWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP=YES ^
   -D SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED=YES ^
   -D SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING=YES ^
   -D SWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING=YES ^
@@ -254,6 +255,7 @@ cmake ^
   -D SWIFT_PATH_TO_STRING_PROCESSING_SOURCE=%SourceRoot%\swift-experimental-string-processing ^
 
   -D SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY=YES ^
+  -D SWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP=YES ^
   -D SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED=YES ^
   -D SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING=YES ^
   -D SWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING=YES ^

utils/build-windows.bat

@@ -262,6 +262,7 @@ cmake^
     -DSWIFT_BUILD_SOURCEKIT:BOOL=YES^
     -DSWIFT_ENABLE_SOURCEKIT_TESTS:BOOL=YES^
     -DSWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY=YES^
+    -DSWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP=YES^
     -DSWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED=YES^
     -DSWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING=YES^
     -DSWIFT_ENABLE_EXPERIMENTAL_STRING_PROCESSING=YES^

utils/build_swift/build_swift/driver_arguments.py

@@ -1321,10 +1321,13 @@ def create_argument_parser():
            default=True,
            help='Enable experimental Swift differentiable programming.')
 
-    option('--enable-experimental-concurrency', toggle_true,
-           default=True,
+    option('--enable-experimental-concurrency', toggle_true, default=True,
            help='Enable experimental Swift concurrency model.')
 
+    option('--enable-experimental-cxx-interop', toggle_true,
+           default=True,
+           help='Enable experimental C++ interop.')
+
     option('--enable-experimental-distributed', toggle_true,
            default=True,
            help='Enable experimental Swift distributed actors.')

utils/swift_build_support/swift_build_support/products/swift.py

@@ -52,6 +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.
+        self.cmake_options.extend(self._enable_experimental_cxx_interop)
+
         # Add experimental distributed flag.
         self.cmake_options.extend(self._enable_experimental_distributed)
 
@@ -168,6 +171,11 @@ def _enable_experimental_concurrency(self):
         return [('SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY:BOOL',
                  self.args.enable_experimental_concurrency)]
 
+    @property
+    def _enable_experimental_cxx_interop(self):
+        return [('SWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP:BOOL',
+                 self.args.enable_experimental_cxx_interop)]
+
     @property
     def _enable_experimental_distributed(self):
         return [('SWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED:BOOL',

utils/swift_build_support/tests/products/test_swift.py

@@ -55,6 +55,7 @@ def setUp(self):
             enable_stdlibcore_exclusivity_checking=False,
             enable_experimental_differentiable_programming=False,
             enable_experimental_concurrency=False,
+            enable_experimental_cxx_interop=False,
             enable_experimental_distributed=False,
             enable_experimental_observation=False,
             swift_enable_backtracing=False,
@@ -96,6 +97,7 @@ def test_by_default_no_cmake_options(self):
             '-DSWIFT_STDLIB_ENABLE_STDLIBCORE_EXCLUSIVITY_CHECKING:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY:BOOL=FALSE',
+            '-DSWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_OBSERVATION:BOOL=FALSE',
             '-DSWIFT_ENABLE_BACKTRACING:BOOL=FALSE',
@@ -121,6 +123,7 @@ def test_swift_runtime_tsan(self):
             '-DSWIFT_STDLIB_ENABLE_STDLIBCORE_EXCLUSIVITY_CHECKING:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY:BOOL=FALSE',
+            '-DSWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_DISTRIBUTED:BOOL=FALSE',
             '-DSWIFT_ENABLE_EXPERIMENTAL_OBSERVATION:BOOL=FALSE',
             '-DSWIFT_ENABLE_BACKTRACING:BOOL=FALSE',
@@ -355,6 +358,18 @@ def test_experimental_concurrency_flags(self):
             [x for x in swift.cmake_options
              if 'DSWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY' in x])
 
+    def test_experimental_cxx_interop_flags(self):
+        self.args.enable_experimental_cxx_interop = True
+        swift = Swift(
+            args=self.args,
+            toolchain=self.toolchain,
+            source_dir='/path/to/src',
+            build_dir='/path/to/build')
+        self.assertEqual(
+            ['-DSWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP:BOOL=TRUE'],
+            [option for option in swift.cmake_options
+             if 'DSWIFT_ENABLE_EXPERIMENTAL_CXX_INTEROP' in option])
+
     def test_experimental_distributed_flags(self):
         self.args.enable_experimental_distributed = True
         swift = Swift(