Unlock C++ interoperability

[kateinoigakukun]

• Reproducer: https://github.com/kateinoigakukun/SwiftPM-Examples/tree/main/CxxInterop-WASILibc
• Toolchain version: swift-DEVELOPMENT-SNAPSHOT-2024-11-20-a
• Swift SDK version: DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads

$ swift build --swift-sdk DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads --target Example
/private/var/folders/k2/q6yzck31253_q1j4kxkzq5jh0000gn/T/tmp.6igJC9tBhY/Sources/CxxTarget/include/check.h:1:10: note: while building module 'std_string' imported from /private/var/folders/k2/q6yzck31253_q1j4kxkzq5jh0000gn/T/tmp.6igJC9tBhY/Sources/CxxTarget/include/check.h:1:
1 | #include <string>
  |          `- note: while building module 'std_string' imported from /private/var/folders/k2/q6yzck31253_q1j4kxkzq5jh0000gn/T/tmp.6igJC9tBhY/Sources/CxxTarget/include/check.h:1:
2 | 

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/string:591:10: note: while building module 'std_private_algorithm_remove' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/string:591:
 589 | #include <__algorithm/max.h>
 590 | #include <__algorithm/min.h>
 591 | #include <__algorithm/remove.h>
     |          `- note: while building module 'std_private_algorithm_remove' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/string:591:
 592 | #include <__algorithm/remove_if.h>
 593 | #include <__assert>

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__algorithm/remove.h:12:10: note: while building module 'std_private_algorithm_find' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__algorithm/remove.h:12:
10 | #define _LIBCPP___ALGORITHM_REMOVE_H
11 | 
12 | #include <__algorithm/find.h>
   |          `- note: while building module 'std_private_algorithm_find' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__algorithm/remove.h:12:
13 | #include <__algorithm/find_if.h>
14 | #include <__config>

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__algorithm/find.h:23:10: note: while building module 'std_private_string_constexpr_c_functions' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__algorithm/find.h:23:
 21 | #include <__fwd/bit_reference.h>
 22 | #include <__iterator/segmented_iterator.h>
 23 | #include <__string/constexpr_c_functions.h>
    |          `- note: while building module 'std_private_string_constexpr_c_functions' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__algorithm/find.h:23:
 24 | #include <__type_traits/is_integral.h>
 25 | #include <__type_traits/is_same.h>

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__string/constexpr_c_functions.h:14:10: note: while building module 'std_private_memory_construct_at' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__string/constexpr_c_functions.h:14:
 12 | #include <__config>
 13 | #include <__memory/addressof.h>
 14 | #include <__memory/construct_at.h>
    |          `- note: while building module 'std_private_memory_construct_at' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__string/constexpr_c_functions.h:14:
 15 | #include <__type_traits/datasizeof.h>
 16 | #include <__type_traits/is_always_bitcastable.h>

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__memory/construct_at.h:23:10: note: while building module 'std_new' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__memory/construct_at.h:23:
 21 | #include <__utility/forward.h>
 22 | #include <__utility/move.h>
 23 | #include <new>
    |          `- note: while building module 'std_new' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/__memory/construct_at.h:23:
 24 | 
 25 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/new:358:12: note: while building module 'std_cstdlib' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/new:358:
356 | 
357 | #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
358 | #  include <cstdlib>
    |            `- note: while building module 'std_cstdlib' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/new:358:
359 | #  include <type_traits>
360 | #endif

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/stdlib.h:94:19: note: while building module 'SwiftWASILibc' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/stdlib.h:94:
 92 | 
 93 | #  if __has_include_next(<stdlib.h>)
 94 | #    include_next <stdlib.h>
    |                   `- note: while building module 'SwiftWASILibc' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/stdlib.h:94:
 95 | #  endif
 96 | 

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/wasm32-wasip1-threads/netinet/in.h:10:10: note: while building module 'std_inttypes_h' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/wasm32-wasip1-threads/netinet/in.h:10:
  8 | #include <features.h>
  9 | // #include <__header_inttypes.h>
 10 | #include <inttypes.h>
    |          `- note: while building module 'std_inttypes_h' imported from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/wasm32-wasip1-threads/netinet/in.h:10:
 11 | #include <sys/socket.h>
 12 | #ifdef __wasilibc_unmodified_upstream /* Use alternate WASI libc headers */

<module-includes>:1:10: note: in file included from <module-includes>:1:
1 | #include "inttypes.h"
  |          `- note: in file included from <module-includes>:1:
2 | 

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/inttypes.h:252:17: note: in file included from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/inttypes.h:252:
250 | 
251 | #if __has_include_next(<inttypes.h>)
252 | #  include_next <inttypes.h>
    |                 `- note: in file included from /Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/WASI.sdk/include/c++/v1/inttypes.h:252:
253 | #endif
254 | 

/Users/katei/Library/org.swift.swiftpm/swift-sdks/swift-wasm-DEVELOPMENT-SNAPSHOT-wasm32-unknown-wasip1-threads.artifactbundle/DEVELOPMENT-SNAPSHOT-2024-11-24-a-wasm32-unknown-wasip1-threads/wasm32-unknown-wasip1-threads/swift.xctoolchain/usr/lib/swift_static/clang/include/inttypes.h:24:15: error: cyclic dependency in module 'SwiftWASILibc': SwiftWASILibc -> std_inttypes_h -> SwiftWASILibc
 22 | #endif
 23 | 
 24 | #include_next <inttypes.h>
    |               `- error: cyclic dependency in module 'SwiftWASILibc': SwiftWASILibc -> std_inttypes_h -> SwiftWASILibc
 25 | 
 26 | #if defined(_MSC_VER) && _MSC_VER < 1900

[kateinoigakukun]

The cycle can be resolved by defining Clang modules in granular units
e.g. in.h -> inttypes.h (libcxx) -> inttypes.h (libc)

I think we can do something like swiftlang#71840