ObjectiveC: Add C17 and C23 support

Issue: #22297

Help/release/dev/objc-std-17-23.rst

@@ -0,0 +1,4 @@
+objc-std-17-23
+--------------
+
+* :prop_tgt:`OBJC_STANDARD` gained support for C17 and C23.

Modules/CMakeOBJCCompiler.cmake.in

@@ -9,6 +9,8 @@ set(CMAKE_OBJC_COMPILE_FEATURES "@CMAKE_OBJC_COMPILE_FEATURES@")
 set(CMAKE_OBJC90_COMPILE_FEATURES "@CMAKE_OBJC90_COMPILE_FEATURES@")
 set(CMAKE_OBJC99_COMPILE_FEATURES "@CMAKE_OBJC99_COMPILE_FEATURES@")
 set(CMAKE_OBJC11_COMPILE_FEATURES "@CMAKE_OBJC11_COMPILE_FEATURES@")
+set(CMAKE_OBJC17_COMPILE_FEATURES "@CMAKE_OBJC17_COMPILE_FEATURES@")
+set(CMAKE_OBJC23_COMPILE_FEATURES "@CMAKE_OBJC23_COMPILE_FEATURES@")
 
 set(CMAKE_OBJC_PLATFORM_ID "@CMAKE_OBJC_PLATFORM_ID@")
 set(CMAKE_OBJC_SIMULATE_ID "@CMAKE_OBJC_SIMULATE_ID@")

Modules/CMakeOBJCCompilerId.m.in

@@ -27,6 +27,10 @@ char const* qnxnto = "INFO" ":" "qnxnto[]";
 # else
 #  define C_DIALECT
 # endif
+#elif __STDC_VERSION__ > 201710L
+# define C_DIALECT "23"
+#elif __STDC_VERSION__ >= 201710L
+# define C_DIALECT "17"
 #elif __STDC_VERSION__ >= 201000L
 # define C_DIALECT "11"
 #elif __STDC_VERSION__ >= 199901L

Modules/Compiler/AppleClang-OBJC.cmake

@@ -23,4 +23,18 @@ if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 4.0)
   set(CMAKE_OBJC11_STANDARD__HAS_FULL_SUPPORT ON)
 endif()
 
-__compiler_check_default_language_standard(OBJC 4.0 99)
+# AppleClang 10.0 was the oldest compiler available to test C17 support
+if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 10.0)
+  set(CMAKE_OBJC17_STANDARD_COMPILE_OPTION "-std=c17")
+  set(CMAKE_OBJC17_EXTENSION_COMPILE_OPTION "-std=gnu17")
+  set(CMAKE_OBJC17_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
+if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 11.0)
+  set(CMAKE_OBJC23_STANDARD_COMPILE_OPTION "-std=c2x")
+  set(CMAKE_OBJC23_EXTENSION_COMPILE_OPTION "-std=gnu2x")
+  set(CMAKE_OBJC23_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
+# AppleClang 10.0 was the oldest compiler available to test default C11 support
+__compiler_check_default_language_standard(OBJC 4.0 99 10.0 11)

Modules/Compiler/Clang-OBJC.cmake

@@ -24,4 +24,16 @@ if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 3.4)
   set(CMAKE_OBJC11_STANDARD__HAS_FULL_SUPPORT ON)
 endif()
 
+if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 6.0)
+  set(CMAKE_OBJC17_STANDARD_COMPILE_OPTION "-std=c17")
+  set(CMAKE_OBJC17_EXTENSION_COMPILE_OPTION "-std=gnu17")
+  set(CMAKE_OBJC17_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
+if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 9.0)
+  set(CMAKE_OBJC23_STANDARD_COMPILE_OPTION "-std=c2x")
+  set(CMAKE_OBJC23_EXTENSION_COMPILE_OPTION "-std=gnu2x")
+  set(CMAKE_OBJC23_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
 __compiler_check_default_language_standard(OBJC 3.4 99 3.6 11)

Source/cmStandardLevelResolver.cxx

@@ -322,8 +322,9 @@ std::unordered_map<std::string, StanardLevelComputer> StandardComputerMapping =
         "CUDA", std::vector<int>{ 03, 11, 14, 17, 20, 23 },
         std::vector<std::string>{ "03", "11", "14", "17", "20", "23" } } },
     { "OBJC",
-      StanardLevelComputer{ "OBJC", std::vector<int>{ 90, 99, 11 },
-                            std::vector<std::string>{ "90", "99", "11" } } },
+      StanardLevelComputer{
+        "OBJC", std::vector<int>{ 90, 99, 11, 17, 23 },
+        std::vector<std::string>{ "90", "99", "11", "17", "23" } } },
     { "OBJCXX",
       StanardLevelComputer{
         "OBJCXX", std::vector<int>{ 98, 11, 14, 17, 20, 23 },