From 2345139ab5b93cea4cf331af8d840ed5f943dbeb Mon Sep 17 00:00:00 2001
From: Evan Wilde <etceterawilde@gmail.com>
Date: Tue, 27 Sep 2022 15:30:46 -0700
Subject: CheckSourceCompiles: Add support for Swift

Plumb through swift `check_source_compiles` support.  Add tests to check
that valid swift sources compile and invalid sources don't.
---
 Modules/Internal/CheckSourceCompiles.cmake                |  3 +++
 Tests/RunCMake/CMakeLists.txt                             |  3 ++-
 .../CheckSourceCompiles/CheckSourceCompilesSwift.cmake    | 15 +++++++++++++++
 Tests/RunCMake/CheckSourceCompiles/RunCMakeTest.cmake     |  4 ++++
 4 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 Tests/RunCMake/CheckSourceCompiles/CheckSourceCompilesSwift.cmake

diff --git a/Modules/Internal/CheckSourceCompiles.cmake b/Modules/Internal/CheckSourceCompiles.cmake
index eadf3da..2d43a76 100644
--- a/Modules/Internal/CheckSourceCompiles.cmake
+++ b/Modules/Internal/CheckSourceCompiles.cmake
@@ -34,6 +34,9 @@ function(CMAKE_CHECK_SOURCE_COMPILES _lang _source _var)
     elseif(_lang STREQUAL "OBJCXX")
       set(_lang_textual "Objective-C++")
       set(_lang_ext "mm")
+    elseif(_lang STREQUAL "Swift")
+      set(_lang_textual "Swift")
+      set(_lang_ext "swift")
     else()
       message (SEND_ERROR "check_source_compiles: ${_lang}: unknown language.")
       return()
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index 6c5ab7f..3f92829 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -752,7 +752,8 @@ add_RunCMake_test(CheckCompilerFlag   -DCMake_TEST_CUDA=${CMake_TEST_CUDA}
 add_RunCMake_test(CheckSourceCompiles -DCMake_TEST_CUDA=${CMake_TEST_CUDA}
                                       -DCMake_TEST_ISPC=${CMake_TEST_ISPC}
                                       -DCMAKE_Fortran_COMPILER_ID=${CMAKE_Fortran_COMPILER_ID}
-                                      -DCMake_TEST_HIP=${CMake_TEST_HIP})
+                                      -DCMake_TEST_HIP=${CMake_TEST_HIP}
+                                      -DCMake_TEST_Swift=${CMake_TEST_Swift})
 add_RunCMake_test(CheckSourceRuns     -DCMake_TEST_CUDA=${CMake_TEST_CUDA}
                                       -DCMAKE_Fortran_COMPILER_ID=${CMAKE_Fortran_COMPILER_ID}
                                       -DCMake_TEST_HIP=${CMake_TEST_HIP})
diff --git a/Tests/RunCMake/CheckSourceCompiles/CheckSourceCompilesSwift.cmake b/Tests/RunCMake/CheckSourceCompiles/CheckSourceCompilesSwift.cmake
new file mode 100644
index 0000000..767fa69
--- /dev/null
+++ b/Tests/RunCMake/CheckSourceCompiles/CheckSourceCompilesSwift.cmake
@@ -0,0 +1,15 @@
+enable_language(Swift)
+include(CheckSourceCompiles)
+
+set(Swift 1) # test that this is tolerated
+
+check_source_compiles(Swift "baz()" SHOULD_FAIL)
+
+if(SHOULD_FAIL)
+  message(SEND_ERROR "invalid Swift source didn't fail.")
+endif()
+
+check_source_compiles(Swift "print(\"Hello, CMake\")" SHOULD_BUILD)
+if(NOT SHOULD_BUILD)
+  message(SEND_ERROR "Test failed for valid Swift source.")
+endif()
diff --git a/Tests/RunCMake/CheckSourceCompiles/RunCMakeTest.cmake b/Tests/RunCMake/CheckSourceCompiles/RunCMakeTest.cmake
index df77d3d..2ed3e36 100644
--- a/Tests/RunCMake/CheckSourceCompiles/RunCMakeTest.cmake
+++ b/Tests/RunCMake/CheckSourceCompiles/RunCMakeTest.cmake
@@ -31,3 +31,7 @@ endif()
 if(CMake_TEST_HIP)
   run_cmake(CheckSourceCompilesHIP)
 endif()
+
+if(CMake_TEST_Swift)
+  run_cmake(CheckSourceCompilesSwift)
+endif()
-- 
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