Merge topic 'msvc-c17' into release-3.22

c5cc4ddac4 MSVC: Add support for C17
6561b032bc MSVC: Tolerate c_std_17 and c_std_23 features on older compiler versions
22f804e0ec MSVC: Refactor C compile features table for C90, C99, and C11

Acked-by: Kitware Robot <[email protected]>
Reviewed-by: Raul Tambre <[email protected]>
Merge-request: !6677

Modules/Compiler/MSVC-C.cmake

@@ -11,6 +11,22 @@ if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 19.27)
   set(CMAKE_C11_STANDARD_COMPILE_OPTION "-std:c11")
   set(CMAKE_C11_EXTENSION_COMPILE_OPTION "-std:c11")
 
+  if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 19.28)
+    set(CMAKE_C90_STANDARD__HAS_FULL_SUPPORT ON)
+    set(CMAKE_C99_STANDARD__HAS_FULL_SUPPORT ON)
+    set(CMAKE_C11_STANDARD__HAS_FULL_SUPPORT ON)
+    set(CMAKE_C17_STANDARD_COMPILE_OPTION "-std:c17")
+    set(CMAKE_C17_EXTENSION_COMPILE_OPTION "-std:c17")
+  else()
+    # Special case for 19.27 (VS 16.7): C11 has partial support.
+    macro(cmake_record_c_compile_features)
+      _has_compiler_features_c(90)
+      _has_compiler_features_c(99)
+      list(APPEND CMAKE_C11_COMPILE_FEATURES c_std_11)
+      set(_result 0) # expected by cmake_determine_compile_features
+    endmacro()
+  endif()
+
   __compiler_check_default_language_standard(C 19.27 99)
 else()
   # MSVC has no specific options to set C language standards, but set them as
@@ -25,41 +41,35 @@ else()
 
   # There is no meaningful default for this
   set(CMAKE_C_STANDARD_DEFAULT "")
+
+  # There are no C compiler modes so we hard-code the known compiler supported
+  # features. Override the default macro for this special case.  Pretend that
+  # all language standards are available so that at least compilation
+  # can be attempted.
+  macro(cmake_record_c_compile_features)
+    list(APPEND CMAKE_C_COMPILE_FEATURES
+      c_std_90
+      c_std_99
+      c_std_11
+      c_std_17
+      c_std_23
+      c_function_prototypes
+      )
+    list(APPEND CMAKE_C90_COMPILE_FEATURES c_std_90 c_function_prototypes)
+    list(APPEND CMAKE_C99_COMPILE_FEATURES c_std_99)
+    list(APPEND CMAKE_C11_COMPILE_FEATURES c_std_11)
+    if (CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 14.0)
+      list(APPEND CMAKE_C_COMPILE_FEATURES c_variadic_macros)
+      list(APPEND CMAKE_C99_COMPILE_FEATURES c_variadic_macros)
+    endif()
+    set(_result 0) # expected by cmake_determine_compile_features
+  endmacro()
 endif()
 
 set(CMAKE_C_COMPILE_OPTIONS_EXPLICIT_LANGUAGE -TC)
 set(CMAKE_C_CLANG_TIDY_DRIVER_MODE "cl")
 set(CMAKE_C_INCLUDE_WHAT_YOU_USE_DRIVER_MODE "cl")
 
-# There are no C compiler modes so we hard-code the known compiler supported
-# features. Override the default macro for this special case.  Pretend that
-# all language standards are available so that at least compilation
-# can be attempted.
-macro(cmake_record_c_compile_features)
-  list(APPEND CMAKE_C_COMPILE_FEATURES
-    c_std_90
-    c_std_99
-    c_std_11
-    c_function_prototypes
-    )
-  list(APPEND CMAKE_C90_COMPILE_FEATURES c_std_90 c_function_prototypes)
-  list(APPEND CMAKE_C99_COMPILE_FEATURES c_std_99)
-  list(APPEND CMAKE_C11_COMPILE_FEATURES c_std_11)
-  if (CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 14.0)
-    list(APPEND CMAKE_C_COMPILE_FEATURES c_variadic_macros)
-    list(APPEND CMAKE_C99_COMPILE_FEATURES c_variadic_macros)
-  endif()
-  if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 19.27)
-    list(APPEND CMAKE_C_COMPILE_FEATURES c_restrict)
-    list(APPEND CMAKE_C99_COMPILE_FEATURES c_restrict)
-  endif()
-  if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 19.28)
-    list(APPEND CMAKE_C_COMPILE_FEATURES c_static_assert)
-    list(APPEND CMAKE_C11_COMPILE_FEATURES c_static_assert)
-  endif()
-  set(_result 0) # expected by cmake_determine_compile_features
-endmacro()
-
 # /JMC "Just My Code" is only supported by MSVC 19.05 onward.
 if (CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 19.05)
   set(CMAKE_C_COMPILE_OPTIONS_JMC "-JMC")