CUDA, CXX, OBJCXX: C++23 support with Clang 12

Clang 12 landed initial support for C++23 language mode flag -std={c|gnu}++2b
in commit 6627a3c2873fdf7ccba1a1573371079be48b36e8.

9 files changed, 39 insertions, 4 deletions

diff --git a/Modules/CMakeCUDACompiler.cmake.in b/Modules/CMakeCUDACompiler.cmake.in
index d4e6e2e..56ae732 100644
--- a/Modules/CMakeCUDACompiler.cmake.in
+++ b/Modules/CMakeCUDACompiler.cmake.in
@@ -12,6 +12,7 @@ set(CMAKE_CUDA11_COMPILE_FEATURES "@CMAKE_CUDA11_COMPILE_FEATURES@")
 set(CMAKE_CUDA14_COMPILE_FEATURES "@CMAKE_CUDA14_COMPILE_FEATURES@")
 set(CMAKE_CUDA17_COMPILE_FEATURES "@CMAKE_CUDA17_COMPILE_FEATURES@")
 set(CMAKE_CUDA20_COMPILE_FEATURES "@CMAKE_CUDA20_COMPILE_FEATURES@")
+set(CMAKE_CUDA23_COMPILE_FEATURES "@CMAKE_CUDA23_COMPILE_FEATURES@")
 
 set(CMAKE_CUDA_PLATFORM_ID "@CMAKE_CUDA_PLATFORM_ID@")
 set(CMAKE_CUDA_SIMULATE_ID "@CMAKE_CUDA_SIMULATE_ID@")
diff --git a/Modules/CMakeCUDACompilerId.cu.in b/Modules/CMakeCUDACompilerId.cu.in
index 2055de2..91039e5 100644
--- a/Modules/CMakeCUDACompilerId.cu.in
+++ b/Modules/CMakeCUDACompilerId.cu.in
@@ -17,7 +17,9 @@ char const* info_simulate = "INFO" ":" "simulate[" SIMULATE_ID "]";
 @CMAKE_CUDA_COMPILER_ID_ERROR_FOR_TEST@
 
 const char* info_language_dialect_default = "INFO" ":" "dialect_default["
-#if __cplusplus > 201703L
+#if __cplusplus > 202002L
+  "23"
+#elif __cplusplus > 201703L
   "20"
 #elif __cplusplus >= 201703L
   "17"
diff --git a/Modules/CMakeCXXCompiler.cmake.in b/Modules/CMakeCXXCompiler.cmake.in
index a235ebb..92ae2ab 100644
--- a/Modules/CMakeCXXCompiler.cmake.in
+++ b/Modules/CMakeCXXCompiler.cmake.in
@@ -11,6 +11,7 @@ set(CMAKE_CXX11_COMPILE_FEATURES "@CMAKE_CXX11_COMPILE_FEATURES@")
 set(CMAKE_CXX14_COMPILE_FEATURES "@CMAKE_CXX14_COMPILE_FEATURES@")
 set(CMAKE_CXX17_COMPILE_FEATURES "@CMAKE_CXX17_COMPILE_FEATURES@")
 set(CMAKE_CXX20_COMPILE_FEATURES "@CMAKE_CXX20_COMPILE_FEATURES@")
+set(CMAKE_CXX23_COMPILE_FEATURES "@CMAKE_CXX23_COMPILE_FEATURES@")
 
 set(CMAKE_CXX_PLATFORM_ID "@CMAKE_CXX_PLATFORM_ID@")
 set(CMAKE_CXX_SIMULATE_ID "@CMAKE_CXX_SIMULATE_ID@")
diff --git a/Modules/CMakeCXXCompilerId.cpp.in b/Modules/CMakeCXXCompilerId.cpp.in
index 672fff8..49d9f0a 100644
--- a/Modules/CMakeCXXCompilerId.cpp.in
+++ b/Modules/CMakeCXXCompilerId.cpp.in
@@ -44,7 +44,9 @@ char const *info_cray = "INFO" ":" "compiler_wrapper[CrayPrgEnv]";
 #endif
 
 const char* info_language_dialect_default = "INFO" ":" "dialect_default["
-#if CXX_STD > 201703L
+#if CXX_STD > 202002L
+  "23"
+#elif CXX_STD > 201703L
   "20"
 #elif CXX_STD >= 201703L
   "17"
diff --git a/Modules/CMakeDetermineCompileFeatures.cmake b/Modules/CMakeDetermineCompileFeatures.cmake
index b50e5f1..c03a85f 100644
--- a/Modules/CMakeDetermineCompileFeatures.cmake
+++ b/Modules/CMakeDetermineCompileFeatures.cmake
@@ -50,6 +50,7 @@ function(cmake_determine_compile_features lang)
     set(CMAKE_CXX14_COMPILE_FEATURES)
     set(CMAKE_CXX17_COMPILE_FEATURES)
     set(CMAKE_CXX20_COMPILE_FEATURES)
+    set(CMAKE_CXX23_COMPILE_FEATURES)
 
     include("${CMAKE_ROOT}/Modules/Internal/FeatureTesting.cmake")
 
@@ -60,6 +61,9 @@ function(cmake_determine_compile_features lang)
       return()
     endif()
 
+    if (CMAKE_CXX20_COMPILE_FEATURES AND CMAKE_CXX23_COMPILE_FEATURES)
+      list(REMOVE_ITEM CMAKE_CXX23_COMPILE_FEATURES ${CMAKE_CXX20_COMPILE_FEATURES})
+    endif()
     if (CMAKE_CXX17_COMPILE_FEATURES AND CMAKE_CXX20_COMPILE_FEATURES)
       list(REMOVE_ITEM CMAKE_CXX20_COMPILE_FEATURES ${CMAKE_CXX17_COMPILE_FEATURES})
     endif()
@@ -80,6 +84,7 @@ function(cmake_determine_compile_features lang)
         ${CMAKE_CXX14_COMPILE_FEATURES}
         ${CMAKE_CXX17_COMPILE_FEATURES}
         ${CMAKE_CXX20_COMPILE_FEATURES}
+        ${CMAKE_CXX23_COMPILE_FEATURES}
       )
     endif()
 
@@ -89,6 +94,7 @@ function(cmake_determine_compile_features lang)
     set(CMAKE_CXX14_COMPILE_FEATURES ${CMAKE_CXX14_COMPILE_FEATURES} PARENT_SCOPE)
     set(CMAKE_CXX17_COMPILE_FEATURES ${CMAKE_CXX17_COMPILE_FEATURES} PARENT_SCOPE)
     set(CMAKE_CXX20_COMPILE_FEATURES ${CMAKE_CXX20_COMPILE_FEATURES} PARENT_SCOPE)
+    set(CMAKE_CXX23_COMPILE_FEATURES ${CMAKE_CXX23_COMPILE_FEATURES} PARENT_SCOPE)
 
     message(CHECK_PASS "done")
 
@@ -100,6 +106,7 @@ function(cmake_determine_compile_features lang)
     set(CMAKE_CUDA14_COMPILE_FEATURES)
     set(CMAKE_CUDA17_COMPILE_FEATURES)
     set(CMAKE_CUDA20_COMPILE_FEATURES)
+    set(CMAKE_CUDA23_COMPILE_FEATURES)
 
     include("${CMAKE_ROOT}/Modules/Internal/FeatureTesting.cmake")
 
@@ -110,7 +117,10 @@ function(cmake_determine_compile_features lang)
       return()
     endif()
 
-  if (CMAKE_CUDA17_COMPILE_FEATURES AND CMAKE_CUDA20_COMPILE_FEATURES)
+    if (CMAKE_CUDA20_COMPILE_FEATURES AND CMAKE_CUDA23_COMPILE_FEATURES)
+      list(REMOVE_ITEM CMAKE_CUDA23_COMPILE_FEATURES ${CMAKE_CUDA20_COMPILE_FEATURES})
+    endif()
+    if (CMAKE_CUDA17_COMPILE_FEATURES AND CMAKE_CUDA20_COMPILE_FEATURES)
       list(REMOVE_ITEM CMAKE_CUDA20_COMPILE_FEATURES ${CMAKE_CUDA17_COMPILE_FEATURES})
     endif()
     if (CMAKE_CUDA14_COMPILE_FEATURES AND CMAKE_CUDA17_COMPILE_FEATURES)
@@ -130,6 +140,7 @@ function(cmake_determine_compile_features lang)
         ${CMAKE_CUDA14_COMPILE_FEATURES}
         ${CMAKE_CUDA17_COMPILE_FEATURES}
         ${CMAKE_CUDA20_COMPILE_FEATURES}
+        ${CMAKE_CUDA23_COMPILE_FEATURES}
       )
     endif()
 
@@ -139,6 +150,7 @@ function(cmake_determine_compile_features lang)
     set(CMAKE_CUDA14_COMPILE_FEATURES ${CMAKE_CUDA14_COMPILE_FEATURES} PARENT_SCOPE)
     set(CMAKE_CUDA17_COMPILE_FEATURES ${CMAKE_CUDA17_COMPILE_FEATURES} PARENT_SCOPE)
     set(CMAKE_CUDA20_COMPILE_FEATURES ${CMAKE_CUDA20_COMPILE_FEATURES} PARENT_SCOPE)
+    set(CMAKE_CUDA23_COMPILE_FEATURES ${CMAKE_CUDA23_COMPILE_FEATURES} PARENT_SCOPE)
 
     message(CHECK_PASS "done")
 
diff --git a/Modules/CMakeOBJCXXCompiler.cmake.in b/Modules/CMakeOBJCXXCompiler.cmake.in
index 18eb7ff..a24582b 100644
--- a/Modules/CMakeOBJCXXCompiler.cmake.in
+++ b/Modules/CMakeOBJCXXCompiler.cmake.in
@@ -11,6 +11,7 @@ set(CMAKE_OBJCXX11_COMPILE_FEATURES "@CMAKE_OBJCXX11_COMPILE_FEATURES@")
 set(CMAKE_OBJCXX14_COMPILE_FEATURES "@CMAKE_OBJCXX14_COMPILE_FEATURES@")
 set(CMAKE_OBJCXX17_COMPILE_FEATURES "@CMAKE_OBJCXX17_COMPILE_FEATURES@")
 set(CMAKE_OBJCXX20_COMPILE_FEATURES "@CMAKE_OBJCXX20_COMPILE_FEATURES@")
+set(CMAKE_OBJCXX23_COMPILE_FEATURES "@CMAKE_OBJCXX23_COMPILE_FEATURES@")
 
 set(CMAKE_OBJCXX_PLATFORM_ID "@CMAKE_OBJCXX_PLATFORM_ID@")
 set(CMAKE_OBJCXX_SIMULATE_ID "@CMAKE_OBJCXX_SIMULATE_ID@")
diff --git a/Modules/CMakeOBJCXXCompilerId.mm.in b/Modules/CMakeOBJCXXCompilerId.mm.in
index fe04de1..e2ac35d 100644
--- a/Modules/CMakeOBJCXXCompilerId.mm.in
+++ b/Modules/CMakeOBJCXXCompilerId.mm.in
@@ -30,7 +30,9 @@ char const* qnxnto = "INFO" ":" "qnxnto[]";
 #endif
 
 const char* info_language_dialect_default = "INFO" ":" "dialect_default["
-#if CXX_STD > 201703L
+#if CXX_STD > 202002L
+  "23"
+#elfif CXX_STD > 201703L
   "20"
 #elif CXX_STD >= 201703L
   "17"
diff --git a/Modules/Compiler/CMakeCommonCompilerMacros.cmake b/Modules/Compiler/CMakeCommonCompilerMacros.cmake
index 7a30ac6..cd897c5 100644
--- a/Modules/Compiler/CMakeCommonCompilerMacros.cmake
+++ b/Modules/Compiler/CMakeCommonCompilerMacros.cmake
@@ -93,6 +93,9 @@ endmacro()
 # Define to allow compile features to be automatically determined
 macro(cmake_record_cxx_compile_features)
   set(_result 0)
+  if(_result EQUAL 0 AND DEFINED CMAKE_CXX23_STANDARD_COMPILE_OPTION)
+    _has_compiler_features_cxx(23)
+  endif()
   if(_result EQUAL 0 AND DEFINED CMAKE_CXX20_STANDARD_COMPILE_OPTION)
     _has_compiler_features_cxx(20)
   endif()
@@ -127,6 +130,9 @@ endmacro()
 
 macro(cmake_record_cuda_compile_features)
   set(_result 0)
+  if(_result EQUAL 0 AND DEFINED CMAKE_CUDA23_STANDARD_COMPILE_OPTION)
+    _has_compiler_features_cuda(23)
+  endif()
   if(_result EQUAL 0 AND DEFINED CMAKE_CUDA20_STANDARD_COMPILE_OPTION)
     _has_compiler_features_cuda(20)
   endif()
diff --git a/Modules/Compiler/Clang.cmake b/Modules/Compiler/Clang.cmake
index 0e4cded..9f900df 100644
--- a/Modules/Compiler/Clang.cmake
+++ b/Modules/Compiler/Clang.cmake
@@ -165,6 +165,11 @@ macro(__compiler_clang_cxx_standards lang)
 
     unset(_clang_version_std17)
 
+    if(NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 12.0)
+      set(CMAKE_${lang}23_STANDARD_COMPILE_OPTION "-std=c++2b")
+      set(CMAKE_${lang}23_EXTENSION_COMPILE_OPTION "-std=gnu++2b")
+    endif()
+
     if("x${CMAKE_${lang}_SIMULATE_ID}" STREQUAL "xMSVC")
       # The MSVC standard library requires C++14, and MSVC itself has no
       # notion of operating in a mode not aware of at least that standard.
@@ -215,6 +220,8 @@ macro(__compiler_clang_cxx_standards lang)
     set(CMAKE_${lang}17_EXTENSION_COMPILE_OPTION "")
     set(CMAKE_${lang}20_STANDARD_COMPILE_OPTION "")
     set(CMAKE_${lang}20_EXTENSION_COMPILE_OPTION "")
+    set(CMAKE_${lang}23_STANDARD_COMPILE_OPTION "")
+    set(CMAKE_${lang}23_EXTENSION_COMPILE_OPTION "")
 
     # There is no meaningful default for this
     set(CMAKE_${lang}_STANDARD_DEFAULT "")
@@ -230,6 +237,7 @@ macro(__compiler_clang_cxx_standards lang)
         cxx_std_14
         cxx_std_17
         cxx_std_20
+        cxx_std_23
         )
       _record_compiler_features(${lang} "" CMAKE_${lang}_COMPILE_FEATURES)
     endmacro()