Make platform information files specific to the CMake version

At the top of a build tree we configure inside the CMakeFiles directory
files such as "CMakeSystem.cmake" and "CMake<lang>Compiler.cmake" to
save information detected about the system and compilers in use.  The
method of detection and the exact results store varies across CMake
versions as things improve.  This leads to problems when loading files
configured by a different version of CMake.  Previously we ignored such
existing files only if the major.minor part of the CMake version
component changed, and depended on the CMakeCache.txt to tell us the
last version of CMake that wrote the files.  This led to problems if the
user deletes the CMakeCache.txt or we add required information to the
files in a patch-level release of CMake (still a "feature point" release
by modern CMake versioning convention).

Ensure that we always have version-consistent platform information files
by storing them in a subdirectory named with the CMake version.  Every
version of CMake will do its own system and compiler identification
checks even when a build tree has already been configured by another
version of CMake.  Stored results will not clobber those from other
versions of CMake which may be run again on the same tree in the future.
Loaded results will match what the system and language modules expect.

Rename the undocumented variable CMAKE_PLATFORM_ROOT_BIN to
CMAKE_PLATFORM_INFO_DIR to clarify its purpose.  The new variable points
at the version-specific directory while the old variable did not.

Modules/CMakeDetermineASMCompiler.cmake

@@ -163,7 +163,7 @@ set(_CMAKE_ASM_COMPILER_ENV_VAR "${CMAKE_ASM${ASM_DIALECT}_COMPILER_ENV_VAR}")
 
 # configure variables set in this file for fast reload later on
 configure_file(${CMAKE_ROOT}/Modules/CMakeASMCompiler.cmake.in
-  ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeASM${ASM_DIALECT}Compiler.cmake IMMEDIATE @ONLY)
+  ${CMAKE_PLATFORM_INFO_DIR}/CMakeASM${ASM_DIALECT}Compiler.cmake IMMEDIATE @ONLY)
 
 set(_CMAKE_ASM_COMPILER)
 set(_CMAKE_ASM_COMPILER_ARG1)

Modules/CMakeDetermineCCompiler.cmake

@@ -171,7 +171,7 @@ if(MSVC_C_ARCHITECTURE_ID)
 endif()
 # configure variables set in this file for fast reload later on
 configure_file(${CMAKE_ROOT}/Modules/CMakeCCompiler.cmake.in
-  "${CMAKE_PLATFORM_ROOT_BIN}/CMakeCCompiler.cmake"
+  ${CMAKE_PLATFORM_INFO_DIR}/CMakeCCompiler.cmake
   @ONLY IMMEDIATE # IMMEDIATE must be here for compatibility mode <= 2.0
   )
 set(CMAKE_C_COMPILER_ENV_VAR "CC")

Modules/CMakeDetermineCXXCompiler.cmake

@@ -167,7 +167,7 @@ if(MSVC_CXX_ARCHITECTURE_ID)
 endif()
 # configure all variables set in this file
 configure_file(${CMAKE_ROOT}/Modules/CMakeCXXCompiler.cmake.in
-  ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeCXXCompiler.cmake
+  ${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXCompiler.cmake
   @ONLY IMMEDIATE # IMMEDIATE must be here for compatibility mode <= 2.0
   )
 

Modules/CMakeDetermineCompilerABI.cmake

@@ -23,7 +23,7 @@ function(CMAKE_DETERMINE_COMPILER_ABI lang src)
     message(STATUS "Detecting ${lang} compiler ABI info")
 
     # Compile the ABI identification source.
-    set(BIN "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeDetermineCompilerABI_${lang}.bin")
+    set(BIN "${CMAKE_PLATFORM_INFO_DIR}/CMakeDetermineCompilerABI_${lang}.bin")
     set(CMAKE_FLAGS )
     if(DEFINED CMAKE_${lang}_VERBOSE_FLAG)
       set(CMAKE_FLAGS "-DCMAKE_EXE_LINKER_FLAGS=${CMAKE_${lang}_VERBOSE_FLAG}")

Modules/CMakeDetermineCompilerId.cmake

@@ -30,7 +30,7 @@ function(CMAKE_DETERMINE_COMPILER_ID lang flagvar src)
   string(REGEX REPLACE " " ";" CMAKE_${lang}_COMPILER_ID_FLAGS_LIST "${CMAKE_${lang}_COMPILER_ID_FLAGS}")
 
   # Compute the directory in which to run the test.
-  set(CMAKE_${lang}_COMPILER_ID_DIR ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CompilerId${lang})
+  set(CMAKE_${lang}_COMPILER_ID_DIR ${CMAKE_PLATFORM_INFO_DIR}/CompilerId${lang})
 
   # Try building with no extra flags and then try each set
   # of helper flags.  Stop when the compiler is identified.
@@ -393,7 +393,7 @@ function(CMAKE_DETERMINE_COMPILER_ID_VENDOR lang)
     # We get here when this function is called not from within CMAKE_DETERMINE_COMPILER_ID()
     # This is done e.g. for detecting the compiler ID for assemblers.
     # Compute the directory in which to run the test and Create a clean working directory.
-    set(CMAKE_${lang}_COMPILER_ID_DIR ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CompilerId${lang})
+    set(CMAKE_${lang}_COMPILER_ID_DIR ${CMAKE_PLATFORM_INFO_DIR}/CompilerId${lang})
     file(REMOVE_RECURSE ${CMAKE_${lang}_COMPILER_ID_DIR})
     file(MAKE_DIRECTORY ${CMAKE_${lang}_COMPILER_ID_DIR})
   endif()

Modules/CMakeDetermineFortranCompiler.cmake

@@ -197,7 +197,7 @@ if(MSVC_Fortran_ARCHITECTURE_ID)
 endif()
 # configure variables set in this file for fast reload later on
 configure_file(${CMAKE_ROOT}/Modules/CMakeFortranCompiler.cmake.in
-  ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeFortranCompiler.cmake
+  ${CMAKE_PLATFORM_INFO_DIR}/CMakeFortranCompiler.cmake
   @ONLY IMMEDIATE # IMMEDIATE must be here for compatibility mode <= 2.0
   )
 set(CMAKE_Fortran_COMPILER_ENV_VAR "FC")

Modules/CMakeDetermineJavaCompiler.cmake

@@ -98,5 +98,5 @@ mark_as_advanced(CMAKE_Java_COMPILER)
 
 # configure variables set in this file for fast reload later on
 configure_file(${CMAKE_ROOT}/Modules/CMakeJavaCompiler.cmake.in
-  ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeJavaCompiler.cmake IMMEDIATE @ONLY)
+  ${CMAKE_PLATFORM_INFO_DIR}/CMakeJavaCompiler.cmake IMMEDIATE @ONLY)
 set(CMAKE_Java_COMPILER_ENV_VAR "JAVA_COMPILER")

Modules/CMakeDetermineRCCompiler.cmake

@@ -63,5 +63,5 @@ endif()
 
 # configure variables set in this file for fast reload later on
 configure_file(${CMAKE_ROOT}/Modules/CMakeRCCompiler.cmake.in
-               ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeRCCompiler.cmake IMMEDIATE)
+               ${CMAKE_PLATFORM_INFO_DIR}/CMakeRCCompiler.cmake IMMEDIATE)
 set(CMAKE_RC_COMPILER_ENV_VAR "RC")

Modules/CMakeDetermineSystem.cmake

@@ -170,7 +170,7 @@ if(CMAKE_BINARY_DIR)
 
   # configure variables set in this file for fast reload, the template file is defined at the top of this file
   configure_file(${CMAKE_ROOT}/Modules/CMakeSystem.cmake.in
-                ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeSystem.cmake
+                ${CMAKE_PLATFORM_INFO_DIR}/CMakeSystem.cmake
                 IMMEDIATE @ONLY)
 
 endif()

Modules/CMakeFindPackageMode.cmake

@@ -47,6 +47,8 @@ macro(ENABLE_LANGUAGE)
   # But in --find-package mode, we don't want (and can't) enable any language.
 endmacro()
 
+set(CMAKE_PLATFORM_INFO_DIR ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY})
+
 include(CMakeDetermineSystem)
 
 # short-cut some tests on Darwin, see Darwin-GNU.cmake:

Modules/CMakeTestCCompiler.cmake

@@ -47,8 +47,8 @@ if(NOT CMAKE_C_COMPILER_WORKS)
   # if the compiler is broken make sure to remove the platform file
   # since Windows-cl configures both c/cxx files both need to be removed
   # when c or c++ fails
-  file(REMOVE ${CMAKE_PLATFORM_ROOT_BIN}/CMakeCPlatform.cmake )
-  file(REMOVE ${CMAKE_PLATFORM_ROOT_BIN}/CMakeCXXPlatform.cmake )
+  file(REMOVE ${CMAKE_PLATFORM_INFO_DIR}/CMakeCPlatform.cmake )
+  file(REMOVE ${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXPlatform.cmake )
   message(FATAL_ERROR "The C compiler \"${CMAKE_C_COMPILER}\" "
     "is not able to compile a simple test program.\nIt fails "
     "with the following output:\n ${__CMAKE_C_COMPILER_OUTPUT}\n\n"
@@ -71,10 +71,10 @@ else()
     CMAKE_DETERMINE_COMPILER_ABI(C ${CMAKE_ROOT}/Modules/CMakeCCompilerABI.c)
     configure_file(
       ${CMAKE_ROOT}/Modules/CMakeCCompiler.cmake.in
-      ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeCCompiler.cmake
+      ${CMAKE_PLATFORM_INFO_DIR}/CMakeCCompiler.cmake
       @ONLY IMMEDIATE # IMMEDIATE must be here for compatibility mode <= 2.0
       )
-    include(${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeCCompiler.cmake)
+    include(${CMAKE_PLATFORM_INFO_DIR}/CMakeCCompiler.cmake)
   endif()
   if(CMAKE_C_SIZEOF_DATA_PTR)
     foreach(f ${CMAKE_C_ABI_FILES})

Modules/CMakeTestCXXCompiler.cmake

@@ -37,8 +37,8 @@ if(NOT CMAKE_CXX_COMPILER_WORKS)
   # if the compiler is broken make sure to remove the platform file
   # since Windows-cl configures both c/cxx files both need to be removed
   # when c or c++ fails
-  file(REMOVE ${CMAKE_PLATFORM_ROOT_BIN}/CMakeCPlatform.cmake )
-  file(REMOVE ${CMAKE_PLATFORM_ROOT_BIN}/CMakeCXXPlatform.cmake )
+  file(REMOVE ${CMAKE_PLATFORM_INFO_DIR}/CMakeCPlatform.cmake )
+  file(REMOVE ${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXPlatform.cmake )
   file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
     "Determining if the CXX compiler works failed with "
     "the following output:\n${__CMAKE_CXX_COMPILER_OUTPUT}\n\n")
@@ -64,10 +64,10 @@ else()
     CMAKE_DETERMINE_COMPILER_ABI(CXX ${CMAKE_ROOT}/Modules/CMakeCXXCompilerABI.cpp)
     configure_file(
       ${CMAKE_ROOT}/Modules/CMakeCXXCompiler.cmake.in
-      ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeCXXCompiler.cmake
+      ${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXCompiler.cmake
       @ONLY IMMEDIATE # IMMEDIATE must be here for compatibility mode <= 2.0
       )
-    include(${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeCXXCompiler.cmake)
+    include(${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXCompiler.cmake)
   endif()
   if(CMAKE_CXX_SIZEOF_DATA_PTR)
     foreach(f ${CMAKE_CXX_ABI_FILES})

Modules/CMakeTestFortranCompiler.cmake

@@ -87,10 +87,10 @@ else()
 
     configure_file(
       ${CMAKE_ROOT}/Modules/CMakeFortranCompiler.cmake.in
-      ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeFortranCompiler.cmake
+      ${CMAKE_PLATFORM_INFO_DIR}/CMakeFortranCompiler.cmake
       @ONLY IMMEDIATE # IMMEDIATE must be here for compatibility mode <= 2.0
       )
-    include(${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeFortranCompiler.cmake)
+    include(${CMAKE_PLATFORM_INFO_DIR}/CMakeFortranCompiler.cmake)
   endif()
   if(CMAKE_Fortran_SIZEOF_DATA_PTR)
     foreach(f ${CMAKE_Fortran_ABI_FILES})

Modules/Platform/Windows-Intel.cmake

@@ -61,7 +61,7 @@ set (CMAKE_MODULE_LINKER_FLAGS_INIT ${CMAKE_SHARED_LINKER_FLAGS_INIT})
 set (CMAKE_MODULE_LINKER_FLAGS_DEBUG_INIT ${CMAKE_SHARED_LINKER_FLAGS_DEBUG_INIT})
 set (CMAKE_MODULE_LINKER_FLAGS_RELWITHDEBINFO_INIT ${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO_INIT})
 
-include("${CMAKE_PLATFORM_ROOT_BIN}/CMakeIntelInformation.cmake" OPTIONAL)
+include("${CMAKE_PLATFORM_INFO_DIR}/CMakeIntelInformation.cmake" OPTIONAL)
 
 if(NOT _INTEL_XILINK_TEST_RUN)
   execute_process(COMMAND xilink /?
@@ -70,8 +70,8 @@ if(NOT _INTEL_XILINK_TEST_RUN)
   if(_XILINK_HELP MATCHES MANIFEST)
     set(_INTEL_COMPILER_SUPPORTS_MANIFEST 1)
   endif()
-  if(NOT  EXISTS "${CMAKE_PLATFORM_ROOT_BIN}/CMakeIntelInformation.cmake")
-    file(WRITE ${CMAKE_PLATFORM_ROOT_BIN}/CMakeIntelInformation.cmake
+  if(NOT  EXISTS "${CMAKE_PLATFORM_INFO_DIR}/CMakeIntelInformation.cmake")
+    file(WRITE ${CMAKE_PLATFORM_INFO_DIR}/CMakeIntelInformation.cmake
       "
 set(_INTEL_XILINK_TEST_RUN 1)
 set(_INTEL_COMPILER_SUPPORTS_MANIFEST ${_INTEL_COMPILER_SUPPORTS_MANIFEST})

Modules/Platform/Windows-cl.cmake

@@ -1,7 +1,7 @@
 # try to load any previously computed information for C on this platform
-include( ${CMAKE_PLATFORM_ROOT_BIN}/CMakeCPlatform.cmake OPTIONAL)
+include( ${CMAKE_PLATFORM_INFO_DIR}/CMakeCPlatform.cmake OPTIONAL)
 # try to load any previously computed information for CXX on this platform
-include( ${CMAKE_PLATFORM_ROOT_BIN}/CMakeCXXPlatform.cmake OPTIONAL)
+include( ${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXPlatform.cmake OPTIONAL)
 
 set(WIN32 1)
 
@@ -242,12 +242,12 @@ set (CMAKE_MODULE_LINKER_FLAGS_RELEASE_INIT ${CMAKE_EXE_LINKER_FLAGS_RELEASE_INI
 set (CMAKE_MODULE_LINKER_FLAGS_MINSIZEREL_INIT ${CMAKE_EXE_LINKER_FLAGS_MINSIZEREL_INIT})
 
 # save computed information for this platform
-if(NOT EXISTS "${CMAKE_PLATFORM_ROOT_BIN}/CMakeCPlatform.cmake")
+if(NOT EXISTS "${CMAKE_PLATFORM_INFO_DIR}/CMakeCPlatform.cmake")
   configure_file(${CMAKE_ROOT}/Modules/Platform/Windows-cl.cmake.in
-    ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeCPlatform.cmake IMMEDIATE)
+    ${CMAKE_PLATFORM_INFO_DIR}/CMakeCPlatform.cmake IMMEDIATE)
 endif()
 
-if(NOT EXISTS "${CMAKE_PLATFORM_ROOT_BIN}/CMakeCXXPlatform.cmake")
+if(NOT EXISTS "${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXPlatform.cmake")
   configure_file(${CMAKE_ROOT}/Modules/Platform/Windows-cl.cmake.in
-               ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeCXXPlatform.cmake IMMEDIATE)
+                 ${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXPlatform.cmake IMMEDIATE)
 endif()

Source/cmGlobalGenerator.cxx

@@ -315,9 +315,11 @@ cmGlobalGenerator::EnableLanguage(std::vector<std::string>const& languages,
     {
     rootBin = this->ConfiguredFilesPath;
     }
+  rootBin += "/";
+  rootBin += cmVersion::GetCMakeVersion();
 
   // set the dir for parent files so they can be used by modules
-  mf->AddDefinition("CMAKE_PLATFORM_ROOT_BIN",rootBin.c_str());
+  mf->AddDefinition("CMAKE_PLATFORM_INFO_DIR",rootBin.c_str());
 
   // find and make sure CMAKE_MAKE_PROGRAM is defined
   this->FindMakeProgram(mf);
@@ -386,14 +388,7 @@ cmGlobalGenerator::EnableLanguage(std::vector<std::string>const& languages,
       // If the existing build tree was already configured with this
       // version of CMake then try to load the configured file first
       // to avoid duplicate compiler tests.
-      unsigned int cacheMajor = mf->GetCacheMajorVersion();
-      unsigned int cacheMinor = mf->GetCacheMinorVersion();
-      unsigned int selfMajor = cmVersion::GetMajorVersion();
-      unsigned int selfMinor = cmVersion::GetMinorVersion();
-      if((this->CMakeInstance->GetIsInTryCompile() ||
-          (cacheMajor == 0 && cacheMinor == 0) ||
-          (selfMajor == cacheMajor && selfMinor == cacheMinor)) &&
-         cmSystemTools::FileExists(fpath.c_str()))
+      if(cmSystemTools::FileExists(fpath.c_str()))
         {
         if(!mf->ReadListFile(0,fpath.c_str()))
           {

Source/cmake.cxx

@@ -2438,9 +2438,6 @@ int cmake::Run(const std::vector<std::string>& args, bool noconfigure)
 
   this->PreLoadCMakeFiles();
 
-  std::string systemFile = this->GetHomeOutputDirectory();
-  systemFile += "/CMakeSystem.cmake";
-
   if ( noconfigure )
     {
     return 0;

Tests/CMakeTests/ToolchainTest.cmake.in

@@ -6,7 +6,7 @@
 macro(MARK_AS_ADVANCED)
 endmacro()
 # set this to a place where we are allowed to write
-set(CMAKE_PLATFORM_ROOT_BIN "${CMAKE_CURRENT_BINARY_DIR}")
+set(CMAKE_PLATFORM_INFO_DIR "${CMAKE_CURRENT_BINARY_DIR}")
 
 # don't run the compiler detection
 set(CMAKE_C_COMPILER_ID_RUN 1)

bootstrap

@@ -160,6 +160,9 @@ CMAKE_PROBLEMATIC_FILES="\
   CMakeSystem.cmake \
   CMakeCCompiler.cmake \
   CMakeCXXCompiler.cmake \
+  */CMakeSystem.cmake \
+  */CMakeCCompiler.cmake \
+  */CMakeCXXCompiler.cmake \
   Source/cmConfigure.h \
   Source/CTest/Curl/config.h \
   Utilities/cmexpat/expatConfig.h \