Swift: Exclude SDK include paths

Populate `CMAKE_Swift_IMPLICIT_INCLUDE_DIRECTORIES` with the macOS SDK's
include directory so that we filter such implicit directories out of
Swift targets.

Fixes: #19845

Modules/CMakeSwiftCompiler.cmake.in

@@ -12,3 +12,5 @@ set(CMAKE_Swift_COMPILER_ENV_VAR "SWIFTC")
 
 set(CMAKE_Swift_COMPILER_ID_RUN 1)
 set(CMAKE_Swift_SOURCE_FILE_EXTENSIONS swift)
+
+set(CMAKE_Swift_IMPLICIT_INCLUDE_DIRECTORIES "@CMAKE_Swift_IMPLICIT_INCLUDE_DIRECTORIES@")

Modules/CMakeTestSwiftCompiler.cmake

@@ -50,6 +50,11 @@ else()
       "the following output:\n${__CMAKE_Swift_COMPILER_OUTPUT}\n\n")
   endif()
 
+  # Unlike C and CXX we do not yet detect any information about the Swift ABI.
+  # However, one of the steps done for C and CXX as part of that detection is
+  # to initialize the implicit include directories.  That is relevant here.
+  set(CMAKE_Swift_IMPLICIT_INCLUDE_DIRECTORIES "${_CMAKE_Swift_IMPLICIT_INCLUDE_DIRECTORIES_INIT}")
+
   # Re-configure to save learned information.
   configure_file(${CMAKE_ROOT}/Modules/CMakeSwiftCompiler.cmake.in
                  ${CMAKE_PLATFORM_INFO_DIR}/CMakeSwiftCompiler.cmake @ONLY)

Modules/Platform/Darwin.cmake

@@ -210,7 +210,7 @@ unset(_apps_paths)
 include(Platform/UnixPaths)
 if(_CMAKE_OSX_SYSROOT_PATH AND EXISTS ${_CMAKE_OSX_SYSROOT_PATH}/usr/include)
   list(APPEND CMAKE_SYSTEM_PREFIX_PATH ${_CMAKE_OSX_SYSROOT_PATH}/usr)
-  foreach(lang C CXX OBJC OBJCXX)
+  foreach(lang C CXX OBJC OBJCXX Swift)
     list(APPEND _CMAKE_${lang}_IMPLICIT_INCLUDE_DIRECTORIES_INIT ${_CMAKE_OSX_SYSROOT_PATH}/usr/include)
   endforeach()
 endif()

Tests/RunCMake/XcodeProject/RunCMakeTest.cmake

@@ -78,6 +78,15 @@ endfunction()
 XcodeObjcxxFlags(XcodeObjcFlags)
 XcodeObjcxxFlags(XcodeObjcxxFlags)
 
+function(XcodeRemoveExcessiveISystem)
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/XcodeRemoveExcessiveISystem-build)
+  run_cmake(XcodeRemoveExcessiveISystem)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  run_cmake_command(XcodeRemoveExcessiveISystem-build ${CMAKE_COMMAND} --build .)
+endfunction()
+
+XcodeRemoveExcessiveISystem()
+
 # Isolate device tests from host architecture selection.
 unset(ENV{CMAKE_OSX_ARCHITECTURES})
 
@@ -297,4 +306,16 @@ if(XCODE_VERSION VERSION_GREATER_EQUAL 8)
   xctest_lookup_test(tvOS appletvsimulator)
 endif()
 
+if(XCODE_VERSION VERSION_GREATER_EQUAL 8)
+  function(XcodeRemoveExcessiveISystemSDK SDK)
+    set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/XcodeRemoveExcessiveISystemSDK-${SDK}-build)
+    set(RunCMake_TEST_OPTIONS "-DCMAKE_SYSTEM_NAME=iOS")
+    run_cmake(XcodeRemoveExcessiveISystem)
+    set(RunCMake_TEST_NO_CLEAN 1)
+    run_cmake_command(XcodeRemoveExcessiveISystemSDK-${SDK}-build ${CMAKE_COMMAND} --build . -- -sdk ${SDK})
+  endfunction()
+
+  XcodeRemoveExcessiveISystemSDK(iphoneos)
+  XcodeRemoveExcessiveISystemSDK(iphonesimulator)
+endif()
 # Please add macOS-only tests above before the device-specific tests.

Tests/RunCMake/XcodeProject/XcodeRemoveExcessiveISystem.cmake

@@ -0,0 +1,52 @@
+cmake_minimum_required (VERSION 3.14)
+
+if(NOT "$ENV{CMAKE_OSX_ARCHITECTURES}" MATCHES "[;$]")
+  set(USE_SWIFT 1)
+else()
+  set(USE_SWIFT 0)
+endif()
+
+if(IOS)
+  set(CMAKE_XCODE_ATTRIBUTE_CODE_SIGNING_REQUIRED NO)
+  set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+  if(XCODE_VERSION VERSION_LESS 9)
+    set(USE_SWIFT 0)
+  endif()
+endif ()
+
+enable_language (CXX)
+
+if(USE_SWIFT)
+  enable_language (Swift)
+  if(NOT XCODE_VERSION VERSION_LESS 10.2)
+    set(CMAKE_Swift_LANGUAGE_VERSION 5.0)
+  elseif(NOT XCODE_VERSION VERSION_LESS 8.0)
+    set(CMAKE_Swift_LANGUAGE_VERSION 3.0)
+  endif()
+endif()
+
+# Try to find ZLIB in the SDK rather than in system locations.
+set(CMAKE_FIND_USE_PACKAGE_ROOT_PATH FALSE)
+set(CMAKE_FIND_USE_CMAKE_PATH FALSE)
+set(CMAKE_FIND_USE_CMAKE_ENVIRONMENT_PATH FALSE)
+set(CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH FALSE)
+list(REMOVE_ITEM CMAKE_SYSTEM_PREFIX_PATH /usr/local /usr / /usr/X11R6 /usr/pkg /opt /sw /opt/local)
+
+find_package(ZLIB REQUIRED)
+add_library (framework_dependency STATIC)
+target_sources (framework_dependency PRIVATE use_cmath.cpp)
+target_link_libraries(framework_dependency INTERFACE ZLIB::ZLIB)
+
+add_library (framework_test SHARED use_cmath.cpp)
+if(USE_SWIFT)
+  target_sources(framework_test PRIVATE foo.swift)
+endif()
+target_link_libraries (framework_test PRIVATE framework_dependency)
+
+set_target_properties (framework_test PROPERTIES
+    FRAMEWORK TRUE
+    FRAMEWORK_VERSION A
+    MACOSX_FRAMEWORK_IDENTIFIER "framework.test"
+    VERSION "1.0"
+    SOVERSION 1.0
+  )

Tests/RunCMake/XcodeProject/foo.swift

@@ -0,0 +1,2 @@
+func foo() {
+}

Tests/RunCMake/XcodeProject/use_cmath.cpp

@@ -0,0 +1,6 @@
+#include <cmath>
+
+bool foo(double arg)
+{
+  return std::isfinite(arg);
+}