Merge pull request apple#42 from FoundationDB/eng/reverse-header-sepa…

…rate-gen-target

[interop] Use a separate target for Swift-to-C++ header generation

cmake/SwiftToCXXInterop.cmake

@@ -1,9 +1,9 @@
 include(CompilerChecks)
 include(FindSwiftLibs)
 
-# Generates a C++ compatibility header for the given target.
-# FIXME: Can we remove the headerName and match the Swift module name?
-function(generate_cxx_compat_header target headerName)
+function(add_swift_to_cxx_header_gen_target target_name header_target_name header_path)
+  cmake_parse_arguments(ARG "" "" "SOURCES;FLAGS" ${ARGN})
+
   # Verify toolchain support.
   get_filename_component(SwiftBinPath ${CMAKE_Swift_COMPILER} DIRECTORY)
   set (SwiftInteropVersionFile ${SwiftBinPath}/../lib/swift/swiftToCxx/experimental-interoperability-version.json)
@@ -17,36 +17,27 @@ function(generate_cxx_compat_header target headerName)
     message(FATAL_ERROR "Swift: reverse interop is required, but not supported. Update your toolchain.")
   endif()
 
-  set(destpath ${CMAKE_CURRENT_BINARY_DIR}/include/SwiftModules)
-  message(STATUS "Swift: C++ compatibility headers for ${target} will be generated in ${destpath}")
-
-  # Generate a directory into which the C++ headers will go.
-  file(MAKE_DIRECTORY ${destpath})
-
-  # Generate the C++ compatibility header for the Swift module.
-  target_compile_options(${target} PRIVATE "$<$<COMPILE_LANGUAGE:Swift>:SHELL: -Xfrontend -emit-clang-header-path -Xfrontend ${destpath}/${headerName}>")
-  # Note: do not generate Stdlib bindings yet (C++20 only).
-  if (${headerName} STREQUAL "Flow")
-    target_compile_options(${target} PRIVATE "$<$<COMPILE_LANGUAGE:Swift>:SHELL: -Xfrontend -clang-header-expose-decls=has-expose-attr>")
-  endif()
-endfunction()
-
-function(add_swift_to_cxx_header_gen_target target_name header_target_name header_path source_path)
-  cmake_parse_arguments(ARG "" "" "FLAGS" ${ARGN})
-
   set(target_includes_expr "$<TARGET_PROPERTY:${target_name},INCLUDE_DIRECTORIES>")
+  if(ARG_SOURCES)
+    set(target_sources ${ARG_SOURCES})
+  else()
+    get_target_property(target_sources ${target_name} SOURCES)
+    get_target_property(target_source_dir ${target_name} SOURCE_DIR)
+    list(TRANSFORM target_sources PREPEND "${target_source_dir}/")
+  endif()
   add_custom_command(
   OUTPUT
     "${header_path}"
   COMMAND
     ${CMAKE_Swift_COMPILER} -frontend -typecheck
-    "${source_path}"
+    ${target_sources}
+    -enable-experimental-cxx-interop
     -module-name "${target_name}"
     -emit-clang-header-path "${header_path}"
     "$<$<BOOL:${target_includes_expr}>:-I$<JOIN:${target_includes_expr},;-I>>"
     ${ARG_FLAGS}
   DEPENDS
-    "${source_path}"
+    "${target_sources}"
   COMMAND_EXPAND_LISTS
   COMMENT
     "Generating '${header_path}'"

fdbclient/CMakeLists.txt

@@ -109,10 +109,6 @@ generate_modulemap("${CMAKE_BINARY_DIR}/fdbclient/include" "FDBClient" fdbclient
 # TODO: the TBD validation skip is because of swift_job_run_generic, though it seems weird why we need to do that?
 target_compile_options(fdbclient_swift PRIVATE "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc -std=c++17 -enable-experimental-cxx-interop -Xfrontend -validate-tbd-against-ir=none -Xcc -DNO_INTELLISENSE -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/flow/include/headeroverlay.yaml -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/fdbclient/include/headeroverlay.yaml -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/fdbclient/include/headeroverlay.yaml>")
 
-# Ensure that C++ code in fdbclient can import Swift using a compatibility header.
-include(SwiftToCXXInterop)
-generate_cxx_compat_header(fdbclient_swift "FDBClient")
-
 add_dependencies(fdbclient_swift flow_swift)
 # This does not work! (see rdar://99107402)
 # target_link_libraries(flow PRIVATE flow_swift)

fdbserver/CMakeLists.txt

@@ -72,17 +72,25 @@ add_swift_to_cxx_header_gen_target(
   fdbserver_swift
   fdbserver_swift_to_cxx_conformance_header
   "${CMAKE_CURRENT_BINARY_DIR}/include/SwiftModules/FDBServer_CxxTypeConformances.h"
+  SOURCES
    "${CMAKE_CURRENT_SOURCE_DIR}/swift_fdbserver_cxx_swift_value_conformance.swift"
    FLAGS
--Xcc -std=c++17 -enable-experimental-cxx-interop -Xcc -DNO_INTELLISENSE -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/flow/include/headeroverlay.yaml -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/fdbclient/include/headeroverlay.yaml -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/fdbserver/include/headeroverlay.yaml
+-Xcc -std=c++17 -Xcc -DNO_INTELLISENSE -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/flow/include/headeroverlay.yaml -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/fdbclient/include/headeroverlay.yaml -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/fdbserver/include/headeroverlay.yaml
 # Important: This is needed to avoid including header that depends on this generated header.
 -Xcc -DFOUNDATIONDB_FDBSERVER_STREAM_SUPPORT_H
 )
 
-generate_cxx_compat_header(fdbserver_swift "FDBServer")
+add_swift_to_cxx_header_gen_target(
+  fdbserver_swift
+  fdbserver_swift_header
+  "${CMAKE_CURRENT_BINARY_DIR}/include/SwiftModules/FDBServer"
+   FLAGS
+-Xcc -std=c++17 -Xcc -DNO_INTELLISENSE -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/flow/include/headeroverlay.yaml -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/fdbclient/include/headeroverlay.yaml -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/fdbserver/include/headeroverlay.yaml
+)
 
-add_dependencies(fdbserver_swift_to_cxx_conformance_header flow_actors fdbserver_actors)
-add_dependencies(fdbserver_swift fdbserver_swift_to_cxx_conformance_header)
+add_dependencies(fdbserver_swift_to_cxx_conformance_header flow_swift flow_swift_header flow_actors fdbserver_actors)
+add_dependencies(fdbserver_swift_header fdbserver_swift_to_cxx_conformance_header)
+add_dependencies(fdbserver_swift fdbserver_swift_header)
 
 add_dependencies(fdbserver_swift flow_swift)
 add_dependencies(fdbserver_swift flow_actors)

flow/CMakeLists.txt

@@ -141,9 +141,9 @@ target_link_directories(flow PUBLIC "${SWIFT_LINK_PATHS}")
 # We need to make sure that Swift, and the concurrency library is linked
 # in every module that uses flow, because we implement the Swift hooks in flow.
 # TODO(swift): With upcoming CMake 3.26 we can get rid of this as it should realize
-#              that modules need Swift and use Swift for the linking which 
+#              that modules need Swift and use Swift for the linking which
 #              will do the right thing.
-target_link_options(flow PUBLIC 
+target_link_options(flow PUBLIC
     "-lswiftCore"
     "-lswift_Concurrency"
     "-lswift_StringProcessing")
@@ -171,17 +171,25 @@ add_swift_to_cxx_header_gen_target(
   flow_swift
   flow_swift_checked_continuation_header
   "${CMAKE_CURRENT_BINARY_DIR}/include/SwiftModules/Flow_CheckedContinuation.h"
+  SOURCES
    "${CMAKE_CURRENT_SOURCE_DIR}/FlowCheckedContinuation.swift"
    FLAGS
--Xcc -std=c++17 -enable-experimental-cxx-interop -Xcc -DNO_INTELLISENSE -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/flow/include/headeroverlay.yaml
+-Xcc -std=c++17 -Xcc -DNO_INTELLISENSE -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/flow/include/headeroverlay.yaml
 # Important: This is needed to avoid including header that depends on this generated header.
 -Xcc -DSWIFT_FUTURE_SUPPORT_H
 )
 
-generate_cxx_compat_header(flow_swift "Flow")
+add_swift_to_cxx_header_gen_target(
+  flow_swift
+  flow_swift_header
+  "${CMAKE_CURRENT_BINARY_DIR}/include/SwiftModules/Flow"
+   FLAGS
+-Xcc -std=c++17 -Xcc -DNO_INTELLISENSE -Xcc -ivfsoverlay${CMAKE_BINARY_DIR}/flow/include/headeroverlay.yaml
+)
 
-add_dependencies(flow_swift_checked_continuation_header flow_actors)
-add_dependencies(flow_swift flow_swift_checked_continuation_header)
+add_dependencies(flow_swift_checked_continuation_header flow_actors boost_targetProject)
+add_dependencies(flow_swift_header flow_swift_checked_continuation_header)
+add_dependencies(flow_swift flow_swift_header)
 
 add_dependencies(flow_swift flow_actors)
 add_dependencies(flow_swift boost_targetProject)