IntelLLVM: Add support for Intel LLVM-based compilers

Using a single ID 'IntelLLVM' for the suite of Intel compilers based on
the LLVM backend.  The 'IntelLLVM' ID are used for C, C++, and Fortran.
Data Parallel C++ will be handled in a separate commit.

The C and C++ definitions are based on the Clang definitions.  The Intel
LLVM-based C and C++ compilers are based on the Clang front end, so
existing Clang options are more likely to be a good match than options
for the older Intel compilers.

Fortran is based on the older Fortran front end with the LLVM backend.
It has a similar interface to the older versions, though many options
are shared with the C and C++ compilers.

Fixes: #21561
Signed-off-by: William R. Dieter <william.r.dieter@intel.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/Modules/Compiler/IntelLLVM-CXX.cmake b/Modules/Compiler/IntelLLVM-CXX.cmake
new file mode 100644
index 0000000..4c0c26e
--- /dev/null
+++ b/Modules/Compiler/IntelLLVM-CXX.cmake
@@ -0,0 +1,69 @@
+include(Compiler/IntelLLVM)
+__compiler_intel_llvm(CXX)
+
+if("x${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC")
+  set(CMAKE_CXX_COMPILE_OPTIONS_EXPLICIT_LANGUAGE -TP)
+  set(CMAKE_CXX_CLANG_TIDY_DRIVER_MODE "cl")
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_CXX)
+    set(CMAKE_CXX_DEPENDS_USE_COMPILER TRUE)
+  endif()
+else()
+  set(CMAKE_CXX_COMPILE_OPTIONS_EXPLICIT_LANGUAGE -x c++)
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_CXX)
+    # dependencies are computed by the compiler itself
+    set(CMAKE_CXX_DEPFILE_FORMAT gcc)
+    set(CMAKE_CXX_DEPENDS_USE_COMPILER TRUE)
+  endif()
+
+  set(CMAKE_CXX_COMPILE_OPTIONS_VISIBILITY_INLINES_HIDDEN "-fvisibility-inlines-hidden")
+
+  string(APPEND CMAKE_CXX_FLAGS_MINSIZEREL_INIT " -DNDEBUG")
+  string(APPEND CMAKE_CXX_FLAGS_RELEASE_INIT " -DNDEBUG")
+  string(APPEND CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT " -DNDEBUG")
+endif()
+
+set(CMAKE_CXX98_STANDARD__HAS_FULL_SUPPORT ON)
+set(CMAKE_CXX11_STANDARD__HAS_FULL_SUPPORT ON)
+set(CMAKE_CXX14_STANDARD__HAS_FULL_SUPPORT ON)
+
+if(NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+  set(CMAKE_CXX98_STANDARD_COMPILE_OPTION  "-std=c++98")
+  set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "-std=gnu++98")
+
+  set(CMAKE_CXX11_STANDARD_COMPILE_OPTION  "-std=c++11")
+  set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-std=gnu++11")
+
+  set(CMAKE_CXX14_STANDARD_COMPILE_OPTION  "-std=c++14")
+  set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-std=gnu++14")
+
+  set(CMAKE_CXX17_STANDARD_COMPILE_OPTION  "-std=c++17")
+  set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-std=gnu++17")
+
+  set(CMAKE_CXX20_STANDARD_COMPILE_OPTION  "-std=c++20")
+  set(CMAKE_CXX20_EXTENSION_COMPILE_OPTION "-std=gnu++20")
+else()
+  set(CMAKE_CXX98_STANDARD_COMPILE_OPTION  "")
+  set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "")
+
+  set(CMAKE_CXX11_STANDARD_COMPILE_OPTION  "-Qstd=c++11")
+  set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-Qstd=c++11")
+
+  set(CMAKE_CXX14_STANDARD_COMPILE_OPTION  "-Qstd=c++14")
+  set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-Qstd=c++14")
+
+  set(CMAKE_CXX17_STANDARD_COMPILE_OPTION  "-Qstd=c++17")
+  set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-Qstd=c++17")
+
+  set(CMAKE_CXX20_STANDARD_COMPILE_OPTION  "-Qstd=c++20")
+  set(CMAKE_CXX20_EXTENSION_COMPILE_OPTION "-Qstd=c++20")
+endif()
+
+if(NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+  __compiler_check_default_language_standard(CXX 2020 14)
+else()
+  set(CMAKE_CXX_STANDARD_DEFAULT "")
+endif()