llvm-rc: Refactor the preprocessing logic

Modules/Platform/Windows-Clang.cmake

@@ -97,6 +97,27 @@ macro(__windows_compiler_clang_gnu lang)
   enable_language(RC)
 endmacro()
 
+macro(__enable_llvm_rc_preprocessing clang_option_prefix)
+  # Feed the preprocessed rc file to llvm-rc
+  if(CMAKE_RC_COMPILER_INIT MATCHES "llvm-rc" OR CMAKE_RC_COMPILER MATCHES "llvm-rc")
+    if(DEFINED CMAKE_C_COMPILER_ID)
+      set(CMAKE_RC_PREPROCESSOR CMAKE_C_COMPILER)
+    elseif(DEFINED CMAKE_CXX_COMPILER_ID)
+      set(CMAKE_RC_PREPROCESSOR CMAKE_CXX_COMPILER)
+    endif()
+    if(DEFINED CMAKE_RC_PREPROCESSOR)
+      set(CMAKE_DEPFILE_FLAGS_RC "${clang_option_prefix}-MD ${clang_option_prefix}-MF ${clang_option_prefix}<DEPFILE>")
+      set(CMAKE_RC_COMPILE_OBJECT "<CMAKE_COMMAND> -E cmake_llvm_rc <SOURCE> <OBJECT>.pp <${CMAKE_RC_PREPROCESSOR}> <DEFINES> -DRC_INVOKED <INCLUDES> <FLAGS> -E -- <SOURCE> ++ <CMAKE_RC_COMPILER> <DEFINES> -I <SOURCE_DIR> <INCLUDES> /fo <OBJECT> <OBJECT>.pp")
+      if(CMAKE_GENERATOR MATCHES "Ninja")
+        set(CMAKE_NINJA_CMCLDEPS_RC 0)
+        set(CMAKE_NINJA_DEP_TYPE_RC gcc)
+      endif()
+      unset(CMAKE_RC_PREPROCESSOR)
+    endif()
+  endif()
+endmacro()
+
+
 if("x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC"
     OR "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
 
@@ -124,7 +145,10 @@ if("x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC"
     if(__RC_COMPILER_PATH)
       set(CMAKE_RC_COMPILER_INIT rc)
     else()
-      set(CMAKE_RC_COMPILER_INIT llvm-rc)
+      find_program(__RC_COMPILER_PATH NAMES llvm-rc)
+      if(__RC_COMPILER_PATH)
+        set(CMAKE_RC_COMPILER_INIT llvm-rc)
+      endif()
     endif()
 
     unset(__RC_COMPILER_PATH CACHE)
@@ -132,25 +156,8 @@ if("x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC"
 
   if ( "x${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC" OR "x${CMAKE_C_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC" )
     include(Platform/Windows-MSVC)
-
-    # Feed the preprocessed rc file to llvm-rc
-    if(CMAKE_RC_COMPILER_INIT MATCHES "llvm-rc")
-      if(DEFINED CMAKE_C_COMPILER_ID)
-        set(CMAKE_RC_PREPROCESSOR CMAKE_C_COMPILER)
-      elseif(DEFINED CMAKE_CXX_COMPILER_ID)
-        set(CMAKE_RC_PREPROCESSOR CMAKE_CXX_COMPILER)
-      endif()
-      if(DEFINED CMAKE_RC_PREPROCESSOR)
-        set(CMAKE_DEPFILE_FLAGS_RC "-clang:-MD -clang:-MF -clang:<DEPFILE>")
-        set(CMAKE_RC_COMPILE_OBJECT "<CMAKE_COMMAND> -E cmake_llvm_rc <SOURCE> <OBJECT>.pp <${CMAKE_RC_PREPROCESSOR}> <DEFINES> -DRC_INVOKED <INCLUDES> <FLAGS> -E -- <SOURCE> ++ <CMAKE_RC_COMPILER> <DEFINES> -I <SOURCE_DIR> <INCLUDES> /fo <OBJECT> <OBJECT>.pp")
-        if(CMAKE_GENERATOR STREQUAL "Ninja")
-          set(CMAKE_NINJA_CMCLDEPS_RC 0)
-          set(CMAKE_NINJA_DEP_TYPE_RC gcc)
-        endif()
-        unset(CMAKE_RC_PREPROCESSOR)
-      endif()
-    endif()
-
+    # Set the clang option forwarding prefix for clang-cl usage in the llvm-rc processing stage
+    __enable_llvm_rc_preprocessing("-clang:")
     macro(__windows_compiler_clang lang)
       set(_COMPILE_${lang} "${_COMPILE_${lang}_MSVC}")
       __windows_compiler_msvc(${lang})