Modules: Introduce CMAKE_EFFECTIVE_SYSTEM_NAME to lookup compiler info

Create a `CMAKE_EFFECTIVE_SYSTEM_NAME` variable to use for looking
up compiler information modules instead of using `CMAKE_SYSTEM_NAME`
directly.  This will allow multiple platforms to share the same set
of compiler information modules without spelling out all of them.

Issue: #17870

8 files changed, 28 insertions, 20 deletions

diff --git a/Modules/CMakeASMInformation.cmake b/Modules/CMakeASMInformation.cmake
index 125c4e3..6b73730 100644
--- a/Modules/CMakeASMInformation.cmake
+++ b/Modules/CMakeASMInformation.cmake
@@ -29,15 +29,15 @@ if(NOT _INCLUDED_FILE)
 endif()
 
 if(CMAKE_SYSTEM_PROCESSOR)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_ASM${ASM_DIALECT}_COMPILER_ID}-ASM${ASM_DIALECT}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL  RESULT_VARIABLE _INCLUDED_FILE)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_ASM${ASM_DIALECT}_COMPILER_ID}-ASM${ASM_DIALECT}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL  RESULT_VARIABLE _INCLUDED_FILE)
   if(NOT _INCLUDED_FILE)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif()
 endif()
 
-include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_ASM${ASM_DIALECT}_COMPILER_ID}-ASM${ASM_DIALECT} OPTIONAL  RESULT_VARIABLE _INCLUDED_FILE)
+include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_ASM${ASM_DIALECT}_COMPILER_ID}-ASM${ASM_DIALECT} OPTIONAL  RESULT_VARIABLE _INCLUDED_FILE)
 if(NOT _INCLUDED_FILE)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL)
 endif()
 
 # This should be included before the _INIT variables are
diff --git a/Modules/CMakeCInformation.cmake b/Modules/CMakeCInformation.cmake
index 1e46cac..df43559 100644
--- a/Modules/CMakeCInformation.cmake
+++ b/Modules/CMakeCInformation.cmake
@@ -35,21 +35,21 @@ endif()
 # load a hardware specific file, mostly useful for embedded compilers
 if(CMAKE_SYSTEM_PROCESSOR)
   if(CMAKE_C_COMPILER_ID)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_C_COMPILER_ID}-C-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_C_COMPILER_ID}-C-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
   endif()
   if (NOT _INCLUDED_FILE)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif ()
 endif()
 
 
 # load the system- and compiler specific files
 if(CMAKE_C_COMPILER_ID)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_C_COMPILER_ID}-C
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_C_COMPILER_ID}-C
     OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
 endif()
 if (NOT _INCLUDED_FILE)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME}
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME}
     OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
 endif ()
 
diff --git a/Modules/CMakeCUDAInformation.cmake b/Modules/CMakeCUDAInformation.cmake
index 4788cbf..479493b 100644
--- a/Modules/CMakeCUDAInformation.cmake
+++ b/Modules/CMakeCUDAInformation.cmake
@@ -17,9 +17,9 @@ endif()
 if(CMAKE_CUDA_COMPILER_ID)
   # load a hardware specific file, mostly useful for embedded compilers
   if(CMAKE_SYSTEM_PROCESSOR)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_CUDA_COMPILER_ID}-CUDA-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_CUDA_COMPILER_ID}-CUDA-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif()
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_CUDA_COMPILER_ID}-CUDA OPTIONAL)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_CUDA_COMPILER_ID}-CUDA OPTIONAL)
 endif()
 
 
diff --git a/Modules/CMakeCXXInformation.cmake b/Modules/CMakeCXXInformation.cmake
index 9ac9560..2975874 100644
--- a/Modules/CMakeCXXInformation.cmake
+++ b/Modules/CMakeCXXInformation.cmake
@@ -36,19 +36,19 @@ endif()
 # load a hardware specific file, mostly useful for embedded compilers
 if(CMAKE_SYSTEM_PROCESSOR)
   if(CMAKE_CXX_COMPILER_ID)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_CXX_COMPILER_ID}-CXX-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_CXX_COMPILER_ID}-CXX-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
   endif()
   if (NOT _INCLUDED_FILE)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif ()
 endif()
 
 # load the system- and compiler specific files
 if(CMAKE_CXX_COMPILER_ID)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_CXX_COMPILER_ID}-CXX OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_CXX_COMPILER_ID}-CXX OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
 endif()
 if (NOT _INCLUDED_FILE)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL
           RESULT_VARIABLE _INCLUDED_FILE)
 endif ()
 
diff --git a/Modules/CMakeFortranInformation.cmake b/Modules/CMakeFortranInformation.cmake
index 5f028e4..cceac83 100644
--- a/Modules/CMakeFortranInformation.cmake
+++ b/Modules/CMakeFortranInformation.cmake
@@ -22,10 +22,10 @@ if(CMAKE_COMPILER_IS_GNUG77)
   set(CMAKE_BASE_NAME g77)
 endif()
 if(CMAKE_Fortran_COMPILER_ID)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_Fortran_COMPILER_ID}-Fortran OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_Fortran_COMPILER_ID}-Fortran OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
 endif()
 if (NOT _INCLUDED_FILE)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL
           RESULT_VARIABLE _INCLUDED_FILE)
 endif ()
 
diff --git a/Modules/CMakeLanguageInformation.cmake b/Modules/CMakeLanguageInformation.cmake
index 18c8624..674ab86 100644
--- a/Modules/CMakeLanguageInformation.cmake
+++ b/Modules/CMakeLanguageInformation.cmake
@@ -9,10 +9,10 @@
 macro(__cmake_include_compiler_wrapper lang)
   set(_INCLUDED_WRAPPER_FILE 0)
   if (CMAKE_${lang}_COMPILER_ID)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_${lang}_COMPILER_WRAPPER}-${CMAKE_${lang}_COMPILER_ID}-${lang} OPTIONAL RESULT_VARIABLE _INCLUDED_WRAPPER_FILE)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_${lang}_COMPILER_WRAPPER}-${CMAKE_${lang}_COMPILER_ID}-${lang} OPTIONAL RESULT_VARIABLE _INCLUDED_WRAPPER_FILE)
   endif()
   if (NOT _INCLUDED_WRAPPER_FILE)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_${lang}_COMPILER_WRAPPER}-${lang} OPTIONAL RESULT_VARIABLE _INCLUDED_WRAPPER_FILE)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_${lang}_COMPILER_WRAPPER}-${lang} OPTIONAL RESULT_VARIABLE _INCLUDED_WRAPPER_FILE)
   endif ()
 
   # No platform - wrapper - lang information so maybe there's just wrapper - lang information
diff --git a/Modules/CMakeSwiftInformation.cmake b/Modules/CMakeSwiftInformation.cmake
index d9b408d..07ba6d0 100644
--- a/Modules/CMakeSwiftInformation.cmake
+++ b/Modules/CMakeSwiftInformation.cmake
@@ -14,9 +14,9 @@ endif()
 if(CMAKE_Swift_COMPILER_ID)
   # load a hardware specific file, mostly useful for embedded compilers
   if(CMAKE_SYSTEM_PROCESSOR)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_Swift_COMPILER_ID}-Swift-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_Swift_COMPILER_ID}-Swift-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif()
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_Swift_COMPILER_ID}-Swift OPTIONAL)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_Swift_COMPILER_ID}-Swift OPTIONAL)
 endif()
 
 # for most systems a module is the same as a shared library
diff --git a/Modules/CMakeSystemSpecificInitialize.cmake b/Modules/CMakeSystemSpecificInitialize.cmake
index 6200e9c..629f226 100644
--- a/Modules/CMakeSystemSpecificInitialize.cmake
+++ b/Modules/CMakeSystemSpecificInitialize.cmake
@@ -5,6 +5,14 @@
 # This file is included by cmGlobalGenerator::EnableLanguage.
 # It is included before the compiler has been determined.
 
+# The CMAKE_EFFECTIVE_SYSTEM_NAME is used to load compiler and compiler
+# wrapper configuration files. By default it equals to CMAKE_SYSTEM_NAME
+# but could be overridden in the ${CMAKE_SYSTEM_NAME}-Initialize files.
+#
+# It is useful to share the same aforementioned configuration files and
+# avoids duplicating them in case of tightly related platforms.
+set(CMAKE_EFFECTIVE_SYSTEM_NAME "${CMAKE_SYSTEM_NAME}")
+
 include(Platform/${CMAKE_SYSTEM_NAME}-Initialize OPTIONAL)
 
 set(CMAKE_SYSTEM_SPECIFIC_INITIALIZE_LOADED 1)