Add a test to verify meta-feature parity with granular features

Tests/RunCMake/CMakeLists.txt

@@ -192,6 +192,9 @@ add_RunCMake_test(GoogleTest) # Note: does not actually depend on Google Test
 add_RunCMake_test(TargetPropertyGeneratorExpressions)
 add_RunCMake_test(Languages)
 add_RunCMake_test(LinkStatic)
+if(CMAKE_CXX_COMPILER_ID MATCHES "^(Cray|PGI|XL|XLClang)$")
+  add_RunCMake_test(MetaCompileFeatures)
+endif()
 add_RunCMake_test(ObjectLibrary)
 add_RunCMake_test(ParseImplicitIncludeInfo)
 if(UNIX AND CMAKE_SHARED_LIBRARY_RUNTIME_C_FLAG AND CMAKE_EXECUTABLE_FORMAT STREQUAL "ELF")

Tests/RunCMake/MetaCompileFeatures/C.cmake

@@ -0,0 +1,27 @@
+
+enable_language(C)
+
+function(check_language_feature_flags lang level)
+  if(CMAKE_${lang}${level}_STANDARD_COMPILE_OPTION)
+    #this property is an internal implementation detail of CMake
+    get_property(known_features GLOBAL PROPERTY CMAKE_${lang}${level}_KNOWN_FEATURES)
+    list(LENGTH known_features len)
+    if(len LESS 1)
+      message(FATAL_ERROR "unable to find known features of ${lang}${level}")
+    endif()
+
+    string(TOLOWER ${lang} lang_lower)
+    set(known_name ${lang_lower}${level}_known_features)
+    set(meta_name  ${lang_lower}${level}_meta_feature)
+
+    add_library(${known_name} STATIC a.c)
+    target_compile_features(${known_name} PUBLIC ${known_features})
+    add_library(${meta_name} STATIC a.c)
+    target_compile_features(${meta_name} PUBLIC ${lang_lower}_std_${level})
+  endif()
+endfunction()
+
+
+check_language_feature_flags(C 90)
+check_language_feature_flags(C 99)
+check_language_feature_flags(C 11)

Tests/RunCMake/MetaCompileFeatures/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.14)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/MetaCompileFeatures/CXX.cmake

@@ -0,0 +1,27 @@
+
+enable_language(CXX)
+
+function(check_language_feature_flags lang level)
+  if(CMAKE_${lang}${level}_STANDARD_COMPILE_OPTION)
+    #this property is an internal implementation detail of CMake
+    get_property(known_features GLOBAL PROPERTY CMAKE_${lang}${level}_KNOWN_FEATURES)
+    list(LENGTH known_features len)
+    if(len LESS 1)
+      message(FATAL_ERROR "unable to find known features of ${lang}${level}")
+    endif()
+
+    string(TOLOWER ${lang} lang_lower)
+    set(known_name ${lang_lower}${level}_known_features)
+    set(meta_name  ${lang_lower}${level}_meta_feature)
+
+    add_library(${known_name} STATIC a.cxx)
+    target_compile_features(${known_name} PUBLIC ${known_features})
+    add_library(${meta_name} STATIC a.cxx)
+    target_compile_features(${meta_name} PUBLIC ${lang_lower}_std_${level})
+  endif()
+endfunction()
+
+
+check_language_feature_flags(CXX 98)
+check_language_feature_flags(CXX 11)
+check_language_feature_flags(CXX 14)

Tests/RunCMake/MetaCompileFeatures/RunCMakeTest.cmake

@@ -0,0 +1,4 @@
+include(RunCMake)
+
+run_cmake(C)
+run_cmake(CXX)