I have a simple CMake project that has a single-header module that imports my C++ library header I want to interface with from Swift.
cmake_minimum_required(VERSION 3.25)
project(lagom-swift LANGUAGES Swift)
add_library(lagom INTERFACE)
target_include_directories(lagom INTERFACE src/include)
target_compile_definitions(lagom INTERFACE "AK_DONT_REPLACE_STD")
target_compile_options(lagom INTERFACE "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xcc -std=c++20>")
target_compile_features(lagom INTERFACE cxx_std_20)
add_executable(WebView
src/WebViewUI.swift
)
target_compile_options(WebView PRIVATE -cxx-interoperability-mode=default)
target_link_libraries(WebView PRIVATE lagom)
This is a minimized example, because what I actually want is to find_package() my library, but that's beside the point here :)
in src/include, I have two files:
module.modulemap
module lagom [system] {
requires cplusplus
module webview {
header "LagomWebView.h"
export *
}
}
and LagomWebView.h
#ifndef LAGOM_WEBVIEW_H
#define LAGOM_WEBVIEW_H
#include <new>
#endif
And a simplified WebViewUI.swift that doesn't do much but import the module:
import Foundation
import lagom.webview
@main
final class WebViewUI: ApplicationDelegate {
func application(_ application: Application,
didFinishLaunchingWithOptions: [Application.LaunchOptionsKey:Any]?) -> Bool {
return true
}
}
Compiling on Ubuntu 22.04.3 LTS fails with a cyclic dependency b/w std and _Builtin_intrinsics. This seems to have something to do with the PSTL implementation for libc++-12.
given:
cmake -B Build -GNinja -DCMAKE_Swift_COMPILER=/home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/bin/swiftc, and compiling, the compiler errors out like so:
Compiler error trace
[1/1] Linking Swift executable WebView
FAILED: WebView CMakeFiles/WebView.dir/src/WebViewUI.swift.o
: && /home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/bin/swiftc -j 32 -num-threads 32 -emit-executable -o WebView -emit-dependencies -DAK_DONT_REPLACE_STD -cxx-interoperability-mode=default -Xcc -std=c++20 -output-file-map CMakeFiles/WebView.dir//output-file-map.json -I /home/andrew/lagom-swift/src/include /home/andrew/lagom-swift/src/WebViewUI.swift && :
/home/andrew/lagom-swift/src/include/LagomWebView.h:4:10: note: while building module 'std' imported from /home/andrew/lagom-swift/src/include/LagomWebView.h:4:
#include <new>
^
/usr/include/tbb/../oneapi/tbb/detail/_machine.h:42:10: note: while building module '_Builtin_intrinsics' imported from /usr/include/tbb/../oneapi/tbb/detail/_machine.h:42:
#include <immintrin.h> // _mm_pause
^
<module-includes>:2:10: note: in file included from <module-includes>:2:
#include "immintrin.h"
^
/home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/lib/swift/clang/include/immintrin.h:26:10: note: in file included from /home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/lib/swift/clang/include/immintrin.h:26:
#include <xmmintrin.h>
^
/home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/lib/swift/clang/include/xmmintrin.h:31:10: note: in file included from /home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/lib/swift/clang/include/xmmintrin.h:31:
#include <mm_malloc.h>
^
/home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/lib/swift/clang/include/mm_malloc.h:13:10: note: in file included from /home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/lib/swift/clang/include/mm_malloc.h:13:
#include <stdlib.h>
^
/usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/stdlib.h:36:11: error: cyclic dependency in module 'std': std -> _Builtin_intrinsics -> std
# include <cstdlib>
^
/home/andrew/lagom-swift/src/include/LagomWebView.h:4:10: note: while building module 'std' imported from /home/andrew/lagom-swift/src/include/LagomWebView.h:4:
#include <new>
^
<module-includes>:1:10: note: in file included from <module-includes>:1:
#include "libstdcxx.h"
^
/home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/lib/swift/linux/x86_64/libstdcxx.h:6:10: note: in file included from /home/andrew/swift/swift-5.9-RELEASE-ubuntu22.04/usr/lib/swift/linux/x86_64/libstdcxx.h:6:
#include "execution"
^
/usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/execution:32:11: note: in file included from /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/execution:32:
# include <pstl/glue_execution_defs.h>
^
/usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/pstl/glue_execution_defs.h:50:10: note: in file included from /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/pstl/glue_execution_defs.h:50:
#include "algorithm_impl.h"
^
/usr/include/c++/12/pstl/algorithm_impl.h:22:10: note: in file included from /usr/include/c++/12/pstl/algorithm_impl.h:22:
#include "parallel_backend.h"
^
/usr/include/c++/12/pstl/parallel_backend.h:20:14: note: in file included from /usr/include/c++/12/pstl/parallel_backend.h:20:
# include "parallel_backend_tbb.h"
^
/usr/include/c++/12/pstl/parallel_backend_tbb.h:19:10: note: in file included from /usr/include/c++/12/pstl/parallel_backend_tbb.h:19:
#include <tbb/blocked_range.h>
^
/usr/include/tbb/blocked_range.h:17:10: note: in file included from /usr/include/tbb/blocked_range.h:17:
#include "../oneapi/tbb/blocked_range.h"
^
/usr/include/tbb/../oneapi/tbb/blocked_range.h:22:10: note: in file included from /usr/include/tbb/../oneapi/tbb/blocked_range.h:22:
#include "detail/_range_common.h"
^
/usr/include/tbb/../oneapi/tbb/detail/_range_common.h:21:10: note: in file included from /usr/include/tbb/../oneapi/tbb/detail/_range_common.h:21:
#include "_utils.h"
^
/usr/include/tbb/../oneapi/tbb/detail/_utils.h:26:10: note: in file included from /usr/include/tbb/../oneapi/tbb/detail/_utils.h:26:
#include "_machine.h"
^
/usr/include/tbb/../oneapi/tbb/detail/_machine.h:42:10: error: could not build module '_Builtin_intrinsics'
#include <immintrin.h> // _mm_pause
^