Merge pull request swiftlang#82134 from etcwilde/ewilde/cache-platform-info

SwiftCore: Cache computed platform info

Author: etcwilde

.gitignore

@@ -97,3 +97,4 @@ Runtimes/**/*.inc
 Runtimes/**/*.json
 Runtimes/**/*.modulemap
 Runtimes/**/*.in
+!Runtimes/**/*.cmake.in

Runtimes/Core/cmake/modules/DetectedPlatformInfo.cmake.in

@@ -0,0 +1,8 @@
+set(SwiftCore_SIZEOF_POINTER @SwiftCore_SIZEOF_POINTER@)
+set(SwiftCore_MODULE_TRIPLE @SwiftCore_MODULE_TRIPLE@)
+set(SwiftCore_PLATFORM_SUBIDR @SwiftCore_PLATFORM_SUBIDR@)
+set(SwiftCore_ARCH_SUBDIR @SwiftCore_ARCH_SUBDIR@)
+
+set(SwiftCore_SWIFT_AVAILABILITY_PLATFORM @SwiftCore_SWIFT_AVAILABILITY_PLATFORM@)
+
+set(SwiftCore_PLATFORM_INFO_SET 1)

Runtimes/Core/cmake/modules/PlatformInfo.cmake

@@ -1,3 +1,9 @@
+include("${PROJECT_BINARY_DIR}/build/DetectedPlatformInfo.cmake" OPTIONAL)
+
+if(SwiftCore_PLATFORM_INFO_SET)
+  return()
+endif()
+
 if(NOT SwiftCore_SIZEOF_POINTER)
   set(SwiftCore_SIZEOF_POINTER "${CMAKE_SIZEOF_VOID_P}" CACHE STRING "Size of a pointer in bytes")
   message(CONFIGURE_LOG "Stdlib Pointer size: ${CMAKE_SIZEOF_VOID_P}")
@@ -80,3 +86,7 @@ if(SwiftCore_VARIANT_MODULE_TRIPLE)
     message(WARNING "Unknown platform ${platform} for variant availability")
   endif()
 endif()
+
+configure_file("${CMAKE_CURRENT_LIST_DIR}/DetectedPlatformInfo.cmake.in"
+  "${PROJECT_BINARY_DIR}/build/DetectedPlatformInfo.cmake"
+  @ONLY)