build: Install libraries in an arch sub-folder

CMakeLists.txt

@@ -306,6 +306,8 @@ add_compile_definitions($<$<COMPILE_LANGUAGE:C,CXX>:HAVE_CONFIG_H>)
 
 
 if(ENABLE_SWIFT)
+  include(SwiftSupport)
+
   if(NOT SWIFT_SYSTEM_NAME)
     if(APPLE)
       set(SWIFT_SYSTEM_NAME macosx)
@@ -314,7 +316,7 @@ if(ENABLE_SWIFT)
     endif()
   endif()
 
-  set(INSTALL_TARGET_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${SWIFT_SYSTEM_NAME}" CACHE PATH "Path where the libraries will be installed")
+  set(INSTALL_TARGET_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${SWIFT_SYSTEM_NAME}/${dispatch_Swift_ARCH}" CACHE PATH "Path where the libraries will be installed")
   set(INSTALL_DISPATCH_HEADERS_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/dispatch" CACHE PATH "Path where the headers will be installed for libdispatch")
   set(INSTALL_BLOCK_HEADERS_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/Block" CACHE PATH "Path where the headers will be installed for the blocks runtime")
   set(INSTALL_OS_HEADERS_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/os" CACHE PATH "Path where the os/ headers will be installed")

cmake/modules/SwiftSupport.cmake

@@ -14,17 +14,47 @@ if(NOT dispatch_MODULE_TRIPLE)
   message(CONFIGURE_LOG "Swift module triple: ${module_triple}")
 endif()
 
+if(NOT dispatch_Swift_ARCH)
+  if(CMAKE_Swift_COMPILER_VERSION VERSION_EQUAL 0.0.0 OR CMAKE_Swift_COMPILER_VERSION VERSION_GREATER_EQUAL 6.2)
+    # For newer compilers, we can use the -print-target-info command to get the architecture.
+    set(module_arch_command "${CMAKE_Swift_COMPILER}" -print-target-info)
+    if(CMAKE_Swift_COMPILER_TARGET)
+      list(APPEND module_arch_command -target ${CMAKE_Swift_COMPILER_TARGET})
+    endif()
+    execute_process(COMMAND ${module_arch_command} OUTPUT_VARIABLE target_info_json)
+    string(JSON module_arch GET "${target_info_json}" "target" "arch")
+  else()
+    # For older compilers, extract the value from `dispatch_MODULE_TRIPLE`.
+    string(REGEX MATCH "^[^-]+" module_arch "${dispatch_MODULE_TRIPLE}")
+  endif()
+
+  set(dispatch_Swift_ARCH "${module_arch}" CACHE STRING "Arch folder name used to install libraries")
+  mark_as_advanced(dispatch_Swift_ARCH)
+
+  message(CONFIGURE_LOG "Swift arch: ${dispatch_Swift_ARCH}")
+endif()
+
 function(install_swift_module target)
   get_target_property(module ${target} Swift_MODULE_NAME)
   if(NOT module)
     set(module ${target})
   endif()
+
+  if(NOT SWIFT_SYSTEM_NAME)
+    if(APPLE)
+      set(SWIFT_SYSTEM_NAME macosx)
+    else()
+      set(SWIFT_SYSTEM_NAME "$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>")
+    endif()
+  endif()
+  set(INSTALL_SWIFT_MODULE_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${SWIFT_SYSTEM_NAME}" CACHE PATH "Path where the swift modules will be installed")
+
   install(
     FILES $<TARGET_PROPERTY:${target},Swift_MODULE_DIRECTORY>/${module}.swiftdoc
-    DESTINATION ${INSTALL_TARGET_DIR}/${module}.swiftmodule
+    DESTINATION ${INSTALL_SWIFT_MODULE_DIR}/${module}.swiftmodule
     RENAME ${dispatch_MODULE_TRIPLE}.swiftdoc)
   install(
     FILES $<TARGET_PROPERTY:${target},Swift_MODULE_DIRECTORY>/${module}.swiftmodule
-    DESTINATION ${INSTALL_TARGET_DIR}/${module}.swiftmodule
+    DESTINATION ${INSTALL_SWIFT_MODULE_DIR}/${module}.swiftmodule
     RENAME ${dispatch_MODULE_TRIPLE}.swiftmodule)
 endfunction()

src/swift/CMakeLists.txt

@@ -1,5 +1,3 @@
-include(SwiftSupport)
-
 if(HAVE_OBJC)
   add_library(DispatchStubs STATIC
     DispatchStubs.m)