[clang] Use enum for LangOptions::SYCLVersion instead of unsigned

`LangOptions::SYCLVersion` can only have two values. This patch introduces an enum that allows us to reduce the member size from 32 bits to 1 bit.

Consequently, this also makes marshalling of this option fit into our model for enums: D84674.

Reviewed By: bader

Differential Revision: https://reviews.llvm.org/D93540

Author: jansvoboda11

clang/include/clang/Basic/LangOptions.def

@@ -246,7 +246,7 @@ LANGOPT(GPUExcludeWrongSideOverloads, 1, 0, "always exclude wrong side overloads
 
 LANGOPT(SYCL              , 1, 0, "SYCL")
 LANGOPT(SYCLIsDevice      , 1, 0, "Generate code for SYCL device")
-LANGOPT(SYCLVersion       , 32, 0, "Version of the SYCL standard used")
+ENUM_LANGOPT(SYCLVersion  , SYCLMajorVersion, 1, SYCL_None, "Version of the SYCL standard used")
 
 LANGOPT(HIPUseNewLaunchAPI, 1, 0, "Use new kernel launching API for HIP")
 

clang/include/clang/Basic/LangOptions.h

@@ -125,6 +125,11 @@ class LangOptions : public LangOptionsBase {
     MSVC2019 = 1920,
   };
 
+  enum SYCLMajorVersion {
+    SYCL_None,
+    SYCL_2017,
+  };
+
   /// Clang versions with different platform ABI conformance.
   enum class ClangABI {
     /// Attempt to be ABI-compatible with code generated by Clang 3.8.x

clang/lib/Frontend/CompilerInvocation.cpp

@@ -2277,11 +2277,13 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     // -sycl-std applies to any SYCL source, not only those containing kernels,
     // but also those using the SYCL API
     if (const Arg *A = Args.getLastArg(OPT_sycl_std_EQ)) {
-      Opts.SYCLVersion = llvm::StringSwitch<unsigned>(A->getValue())
-                             .Cases("2017", "1.2.1", "121", "sycl-1.2.1", 2017)
-                             .Default(0U);
+      Opts.setSYCLVersion(
+          llvm::StringSwitch<LangOptions::SYCLMajorVersion>(A->getValue())
+              .Cases("2017", "1.2.1", "121", "sycl-1.2.1",
+                     LangOptions::SYCL_2017)
+              .Default(LangOptions::SYCL_None));
 
-      if (Opts.SYCLVersion == 0U) {
+      if (Opts.getSYCLVersion() == LangOptions::SYCL_None) {
         // User has passed an invalid value to the flag, this is an error
         Diags.Report(diag::err_drv_invalid_value)
             << A->getAsString(Args) << A->getValue();

clang/lib/Frontend/InitPreprocessor.cpp

@@ -476,7 +476,7 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
 
   if (LangOpts.SYCL) {
     // SYCL Version is set to a value when building SYCL applications
-    if (LangOpts.SYCLVersion == 2017)
+    if (LangOpts.getSYCLVersion() == LangOptions::SYCL_2017)
       Builder.defineMacro("CL_SYCL_LANGUAGE_VERSION", "121");
   }