build: adopt current best practices for installation

Add the `*_INSTALL_NESTED_SUBDIR` option and use `-print-target-info` to
compute the install locations. This reduces the number of times we need
to invoke the compiler and compute these values.

Author: compnerd

CMakeLists.txt

@@ -27,14 +27,6 @@ endif()
 project(SwiftFoundation
     LANGUAGES C Swift)
 
-if(NOT SWIFT_SYSTEM_NAME)
-  if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
-    set(SWIFT_SYSTEM_NAME macosx)
-  else()
-    set(SWIFT_SYSTEM_NAME "$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>")
-  endif()
-endif()
-
 # Don't enable WMO on Windows hosts due to linker failures, and the use of swift's
 # old driver from build.ps1 when building for windows/android on a windows host.
 if(NOT CMAKE_HOST_SYSTEM_NAME STREQUAL Windows)
@@ -145,6 +137,12 @@ if(CMAKE_SYSTEM_NAME STREQUAL "WASI")
 endif()
 
 include(GNUInstallDirs)
+include(PlatformInfo)
+
+option(SwiftFoundation_INSTALL_NESTED_SUBDIR "Install libraries under a platform and architecture subdirectory" NO)
+set(SwiftFoundation_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${SwiftFoundation_PLATFORM_SUBDIR}$<$<BOOL:${SwiftFoundation_INSTALL_NESTED_SUBDIR}>:/${SwiftFoundation_ARCH_SUBDIR}>")
+set(SwiftFoundation_INSTALL_SWIFTMODULEDIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${SwiftFoundation_PLATFORM_SUBDIR}")
+
 include(SwiftFoundationSwiftSupport)
 
 add_subdirectory(Sources)

Sources/_FoundationCShims/CMakeLists.txt

@@ -24,12 +24,6 @@ target_compile_options(_FoundationCShims INTERFACE
 
 set_property(GLOBAL APPEND PROPERTY SWIFT_FOUNDATION_EXPORTS _FoundationCShims)
 
-if(BUILD_SHARED_LIBS)
-    set(install_directory swift)
-else()
-    set(install_directory swift_static)
-endif()
-
 # Copy Headers to known directory for direct client (XCTest) test builds
 file(COPY
         include/
@@ -40,13 +34,12 @@ file(COPY
 install(DIRECTORY
             include/
         DESTINATION
-            lib/${install_directory}/_FoundationCShims)
+            lib/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/_FoundationCShims)
 
 if(NOT BUILD_SHARED_LIBS)
-    get_swift_host_os(swift_os)
     install(TARGETS _FoundationCShims
-        ARCHIVE DESTINATION lib/${install_directory}/${swift_os}
-        LIBRARY DESTINATION lib/${install_directory}/${swift_os}
+        ARCHIVE DESTINATION lib/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${Foundation_PLATFORM_SUBDIR}
+        LIBRARY DESTINATION lib/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${Foundation_PLATFORM_SUBDIR}
         RUNTIME DESTINATION bin)
 endif()
 

cmake/modules/PlatformInfo.cmake

@@ -0,0 +1,54 @@
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the Swift open source project
+##
+## Copyright (c) 2024 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0
+##
+## See LICENSE.txt for license information
+## See CONTRIBUTORS.md for the list of Swift project authors
+##
+## SPDX-License-Identifier: Apache-2.0
+##
+##===----------------------------------------------------------------------===##
+
+set(print_target_info_invocation "${CMAKE_Swift_COMPILER}" -print-target-info)
+if(CMAKE_Swift_COMPILER_TARGET)
+  list(APPEND print_target_info_invocation -target ${CMAKE_Swift_COMPILER_TARGET})
+endif()
+execute_process(COMMAND ${print_target_info_invocation} OUTPUT_VARIABLE target_info_json)
+message(CONFIGURE_LOG "Swift Target Info: ${print_target_info_invocation}\n"
+"${target_info_json}")
+
+if(NOT SwiftFoundation_MODULE_TRIPLE)
+  string(JSON module_triple GET "${target_info_json}" "target" "moduleTriple")
+  set(SwiftFoundation_MODULE_TRIPLE "${module_triple}" CACHE STRING "Triple used for installed swift{doc,module,interface} files")
+  mark_as_advanced(SwiftFoundation_MODULE_TRIPLE)
+
+  message(CONFIGURE_LOG "Swift Module Triple: ${module_triple}")
+endif()
+
+if(NOT SwiftFoundation_PLATFORM_SUBDIR)
+  string(JSON platform GET "${target_info_json}" "target" "platform")
+  if(NOT platform)
+    if(NOT SWIFT_SYSTEM_NAME)
+      if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
+        set(platform macosx)
+      else()
+        set(platform $<LOWER_CASE:${CMAKE_SYSTEM_NAME}>)
+      endif()
+    endif()
+  endif()
+  set(SwiftFoundation_PLATFORM_SUBDIR "${platform}" CACHE STRING "Platform name used for installed swift{doc,module,interface} files")
+  mark_as_advanced(SwiftFoundation_PLATFORM_SUBDIR)
+
+  message(CONFIGURE_LOG "Swift Platform: ${platform}")
+endif()
+
+if(NOT SwiftFoundation_ARCH_SUBDIR)
+  string(JSON arch GET "${target_info_json}" "target" "arch")
+  set(SwiftFoundation_ARCH_SUBDIR "${arch}" CACHE STRING "Architecture used for setting the architecture subdirectory")
+  mark_as_advanced(SwiftFoundation_ARCH_SUBDIR)
+
+  message(CONFIGURE_LOG "Swift Architecture: ${arch}")
+endif()

cmake/modules/SwiftFoundationSwiftSupport.cmake

@@ -1,54 +1,21 @@
-# Returns the os name in a variable
-#
-# Usage:
-#   get_swift_host_os(result_var_name)
-#
-#
-# Sets ${result_var_name} with the converted OS name derived from
-# CMAKE_SYSTEM_NAME.
-function(get_swift_host_os result_var_name)
-  set(${result_var_name} ${SWIFT_SYSTEM_NAME} PARENT_SCOPE)
-endfunction()
-
 function(_swift_foundation_install_target module)
-  get_swift_host_os(swift_os)
-  get_target_property(type ${module} TYPE)
-
-  if(type STREQUAL STATIC_LIBRARY)
-    set(swift swift_static)
-  else()
-    set(swift swift)
-  endif()
-
   install(TARGETS ${module}
-    ARCHIVE DESTINATION lib/${swift}/${swift_os}
-    LIBRARY DESTINATION lib/${swift}/${swift_os}
+    ARCHIVE DESTINATION ${SwiftFoundation_INSTALL_LIBDIR}
+    LIBRARY DESTINATION ${SwiftFoundation_INSTALL_LIBDIR}
     RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
-  if(type STREQUAL EXECUTABLE)
-    return()
-  endif()
 
   get_target_property(module_name ${module} Swift_MODULE_NAME)
   if(NOT module_name)
     set(module_name ${module})
   endif()
 
-  if(NOT SwiftFoundation_MODULE_TRIPLE)
-    set(module_triple_command "${CMAKE_Swift_COMPILER}" -print-target-info)
-    if(CMAKE_Swift_COMPILER_TARGET)
-      list(APPEND module_triple_command -target ${CMAKE_Swift_COMPILER_TARGET})
-    endif()
-    execute_process(COMMAND ${module_triple_command} OUTPUT_VARIABLE target_info_json)
-    string(JSON module_triple GET "${target_info_json}" "target" "moduleTriple")
-    set(SwiftFoundation_MODULE_TRIPLE "${module_triple}" CACHE STRING "swift module triple used for installed swiftmodule and swiftinterface files")
-    mark_as_advanced(SwiftFoundation_MODULE_TRIPLE)
-  endif()
-
   install(FILES $<TARGET_PROPERTY:${module},Swift_MODULE_DIRECTORY>/${module_name}.swiftdoc
-    DESTINATION lib/${swift}/${swift_os}/${module_name}.swiftmodule
+    DESTINATION ${SwiftFoundation_INSTALL_SWIFTMODULEDIR}/${module_name}.swiftmodule
     RENAME ${SwiftFoundation_MODULE_TRIPLE}.swiftdoc)
   install(FILES $<TARGET_PROPERTY:${module},Swift_MODULE_DIRECTORY>/${module_name}.swiftmodule
-    DESTINATION lib/${swift}/${swift_os}/${module_name}.swiftmodule
+    DESTINATION ${SwiftFoundation_INSTALL_SWIFTMODULEDIR}/${module_name}.swiftmodule
     RENAME ${SwiftFoundation_MODULE_TRIPLE}.swiftmodule)
-
+  install(FILES $<TARGET_PROPERTY:${module},Swift_MODULE_DIRECTORY>/${module_name}.swiftsourceinfo
+    DESTINATION ${SwiftFoundation_INSTALL_SWIFTMODULEDIR}/${module_name}.swiftmodule
+    RENAME ${SwiftFoundation_MODULE_TRIPLE}.swiftsourceinfo)
 endfunction()