Languages: Add support for Objective-C++

Add entries in Modules and Modules/Platform to support
Objective-C++ compiler determination and identification.
Add Modules to check Objective-C++ compiler flags, source
compilations, program checks, etc...

Use OBJCXX as the designator of the language, eg:

project(foo OBJCXX)

Add various tests for Objective-C++ language features.  Add
tests to preserve C++ handling of .M and .mm files when
Objective-C++ is not a configured language.

Co-authored-by: Cristian Adam <cristian.adam@gmail.com>

1 files changed, 79 insertions, 0 deletions

diff --git a/Modules/CMakeOBJCXXCompiler.cmake.in b/Modules/CMakeOBJCXXCompiler.cmake.in
new file mode 100644
index 0000000..b6452c4
--- /dev/null
+++ b/Modules/CMakeOBJCXXCompiler.cmake.in
@@ -0,0 +1,79 @@
+set(CMAKE_OBJCXX_COMPILER "@CMAKE_OBJCXX_COMPILER@")
+set(CMAKE_OBJCXX_COMPILER_ARG1 "@CMAKE_OBJCXX_COMPILER_ARG1@")
+set(CMAKE_OBJCXX_COMPILER_ID "@CMAKE_OBJCXX_COMPILER_ID@")
+set(CMAKE_OBJCXX_COMPILER_VERSION "@CMAKE_OBJCXX_COMPILER_VERSION@")
+set(CMAKE_OBJCXX_COMPILER_VERSION_INTERNAL "@CMAKE_OBJCXX_COMPILER_VERSION_INTERNAL@")
+set(CMAKE_OBJCXX_COMPILER_WRAPPER "@CMAKE_OBJCXX_COMPILER_WRAPPER@")
+set(CMAKE_OBJCXX_STANDARD_COMPUTED_DEFAULT "@CMAKE_OBJCXX_STANDARD_COMPUTED_DEFAULT@")
+set(CMAKE_OBJCXX_COMPILE_FEATURES "@CMAKE_OBJCXX_COMPILE_FEATURES@")
+set(CMAKE_OBJCXX98_COMPILE_FEATURES "@CMAKE_OBJCXX98_COMPILE_FEATURES@")
+set(CMAKE_OBJCXX11_COMPILE_FEATURES "@CMAKE_OBJCXX11_COMPILE_FEATURES@")
+set(CMAKE_OBJCXX14_COMPILE_FEATURES "@CMAKE_OBJCXX14_COMPILE_FEATURES@")
+set(CMAKE_OBJCXX17_COMPILE_FEATURES "@CMAKE_OBJCXX17_COMPILE_FEATURES@")
+set(CMAKE_OBJCXX20_COMPILE_FEATURES "@CMAKE_OBJCXX20_COMPILE_FEATURES@")
+
+set(CMAKE_OBJCXX_PLATFORM_ID "@CMAKE_OBJCXX_PLATFORM_ID@")
+set(CMAKE_OBJCXX_SIMULATE_ID "@CMAKE_OBJCXX_SIMULATE_ID@")
+set(CMAKE_OBJCXX_COMPILER_FRONTEND_VARIANT "@CMAKE_OBJCXX_COMPILER_FRONTEND_VARIANT@")
+set(CMAKE_OBJCXX_SIMULATE_VERSION "@CMAKE_OBJCXX_SIMULATE_VERSION@")
+@_SET_CMAKE_OBJCXX_COMPILER_ARCHITECTURE_ID@
+@SET_CMAKE_XCODE_ARCHS@
+set(CMAKE_AR "@CMAKE_AR@")
+set(CMAKE_OBJCXX_COMPILER_AR "@CMAKE_OBJCXX_COMPILER_AR@")
+set(CMAKE_RANLIB "@CMAKE_RANLIB@")
+set(CMAKE_OBJCXX_COMPILER_RANLIB "@CMAKE_OBJCXX_COMPILER_RANLIB@")
+set(CMAKE_LINKER "@CMAKE_LINKER@")
+set(CMAKE_MT "@CMAKE_MT@")
+set(CMAKE_COMPILER_IS_GNUOBJCXX @CMAKE_COMPILER_IS_GNUOBJCXX@)
+set(CMAKE_OBJCXX_COMPILER_LOADED 1)
+set(CMAKE_OBJCXX_COMPILER_WORKS @CMAKE_OBJCXX_COMPILER_WORKS@)
+set(CMAKE_OBJCXX_ABI_COMPILED @CMAKE_OBJCXX_ABI_COMPILED@)
+
+set(CMAKE_OBJCXX_COMPILER_ENV_VAR "OBJCXX")
+
+set(CMAKE_OBJCXX_COMPILER_ID_RUN 1)
+set(CMAKE_OBJCXX_SOURCE_FILE_EXTENSIONS M;m;mm)
+set(CMAKE_OBJCXX_IGNORE_EXTENSIONS inl;h;hpp;HPP;H;o;O)
+
+if (CMAKE_OBJC_COMPILER_ID_RUN)
+  foreach(extension IN LISTS CMAKE_OBJC_SOURCE_FILE_EXTENSIONS)
+    list(REMOVE_ITEM CMAKE_OBJCXX_SOURCE_FILE_EXTENSIONS ${extension})
+  endforeach()
+endif()
+
+foreach (lang C CXX OBJC)
+  foreach(extension IN LISTS CMAKE_OBJCXX_SOURCE_FILE_EXTENSIONS)
+    if (CMAKE_${lang}_COMPILER_ID_RUN)
+      list(REMOVE_ITEM CMAKE_${lang}_SOURCE_FILE_EXTENSIONS ${extension})
+    endif()
+  endforeach()
+endforeach()
+
+set(CMAKE_OBJCXX_LINKER_PREFERENCE 25)
+set(CMAKE_OBJCXX_LINKER_PREFERENCE_PROPAGATES 1)
+
+# Save compiler ABI information.
+set(CMAKE_OBJCXX_SIZEOF_DATA_PTR "@CMAKE_OBJCXX_SIZEOF_DATA_PTR@")
+set(CMAKE_OBJCXX_COMPILER_ABI "@CMAKE_OBJCXX_COMPILER_ABI@")
+set(CMAKE_OBJCXX_LIBRARY_ARCHITECTURE "@CMAKE_OBJCXX_LIBRARY_ARCHITECTURE@")
+
+if(CMAKE_OBJCXX_SIZEOF_DATA_PTR)
+  set(CMAKE_SIZEOF_VOID_P "${CMAKE_OBJCXX_SIZEOF_DATA_PTR}")
+endif()
+
+if(CMAKE_OBJCXX_COMPILER_ABI)
+  set(CMAKE_INTERNAL_PLATFORM_ABI "${CMAKE_OBJCXX_COMPILER_ABI}")
+endif()
+
+if(CMAKE_OBJCXX_LIBRARY_ARCHITECTURE)
+  set(CMAKE_LIBRARY_ARCHITECTURE "@CMAKE_OBJCXX_LIBRARY_ARCHITECTURE@")
+endif()
+
+@CMAKE_OBJCXX_COMPILER_CUSTOM_CODE@
+@CMAKE_OBJCXX_SYSROOT_FLAG_CODE@
+@CMAKE_OBJCXX_OSX_DEPLOYMENT_TARGET_FLAG_CODE@
+
+set(CMAKE_OBJCXX_IMPLICIT_INCLUDE_DIRECTORIES "@CMAKE_OBJCXX_IMPLICIT_INCLUDE_DIRECTORIES@")
+set(CMAKE_OBJCXX_IMPLICIT_LINK_LIBRARIES "@CMAKE_OBJCXX_IMPLICIT_LINK_LIBRARIES@")
+set(CMAKE_OBJCXX_IMPLICIT_LINK_DIRECTORIES "@CMAKE_OBJCXX_IMPLICIT_LINK_DIRECTORIES@")
+set(CMAKE_OBJCXX_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES "@CMAKE_OBJCXX_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES@")