Merge topic 'mingw-objc-objcxx' into release-3.29

2a4e8f03 MinGW: Add support for OBJC and OBJCXX

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Cristian Adam <cristian.adam@gmail.com>
Merge-request: !9244

Help/release/3.29.rst

@@ -39,6 +39,11 @@ Compilers
 * The LLVM/Clang GNU-like frontend on Windows (``clang++``) may now be used
   to compile ``CUDA`` language sources.
 
+* Compilers targeting the GNU ABI on Windows (MinGW) may now be used to
+  compile Objective C (``OBJC``) and Objective C++ (``OBJCXX``).  These
+  include GNU compilers (``gcc`` and ``g++``) and the LLVM/Clang GNU-like
+  frontends (``clang`` and ``clang++``).
+
 * TI Clang-based compilers are now supported with
   :variable:`compiler id <CMAKE_<LANG>_COMPILER_ID>` ``TIClang``.
 

Modules/Platform/Windows-Clang-OBJC.cmake

+include(Platform/Windows-Clang)
+__windows_compiler_clang(OBJC)
+
+if("x${CMAKE_OBJC_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC")
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_OBJC)
+    set(CMAKE_OBJC_DEPENDS_USE_COMPILER TRUE)
+  endif()
+elseif("x${CMAKE_OBJC_COMPILER_FRONTEND_VARIANT}" STREQUAL "xGNU")
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_OBJC)
+    # dependencies are computed by the compiler itself
+    set(CMAKE_OBJC_DEPFILE_FORMAT gcc)
+    set(CMAKE_OBJC_DEPENDS_USE_COMPILER TRUE)
+  endif()
+endif()

Modules/Platform/Windows-Clang-OBJCXX.cmake

+include(Platform/Windows-Clang)
+__windows_compiler_clang(OBJCXX)
+
+if("x${CMAKE_OBJCXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC")
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_OBJCXX)
+    set(CMAKE_OBJCXX_DEPENDS_USE_COMPILER TRUE)
+  endif()
+elseif("x${CMAKE_OBJCXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "xGNU")
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_OBJCXX)
+    # dependencies are computed by the compiler itself
+    set(CMAKE_OBJCXX_DEPFILE_FORMAT gcc)
+    set(CMAKE_OBJCXX_DEPENDS_USE_COMPILER TRUE)
+  endif()
+endif()

Modules/Platform/Windows-GNU-OBJC-ABI.cmake

+__windows_compiler_gnu_abi(OBJC)

Modules/Platform/Windows-GNU-OBJC.cmake

+include(Platform/Windows-GNU)
+__windows_compiler_gnu(OBJC)

Modules/Platform/Windows-GNU-OBJCXX-ABI.cmake

+__windows_compiler_gnu_abi(OBJCXX)

Modules/Platform/Windows-GNU-OBJCXX.cmake

+include(Platform/Windows-GNU)
+__windows_compiler_gnu(OBJCXX)