[clang] [OpenACC] Implement Atomic construct variants (PR #73015)

[Alexey Bataev via cfe-commits]

================
@@ -59,9 +60,21 @@ OpenACCDirectiveKindEx getOpenACCDirectiveKind(StringRef Name) {
   return llvm::StringSwitch<OpenACCDirectiveKindEx>(Name)
       .Case("enter", OpenACCDirectiveKindEx::Enter)
       .Case("exit", OpenACCDirectiveKindEx::Exit)
+      .Case("atomic", OpenACCDirectiveKindEx::Atomic)
       .Default(OpenACCDirectiveKindEx::Invalid);
 }
 
+// Since 'atomic' is effectively a compound directive, this will decode the
+// second part of the directive.
+OpenACCDirectiveKind getOpenACCAtomicDirectiveKind(StringRef Name) {
+  return llvm::StringSwitch<OpenACCDirectiveKind>(Name)
+      .Case("read", OpenACCDirectiveKind::AtomicRead)
+      .Case("write", OpenACCDirectiveKind::AtomicWrite)
+      .Case("update", OpenACCDirectiveKind::AtomicUpdate)
+      .Case("capture", OpenACCDirectiveKind::AtomicCapture)
----------------
alexey-bataev wrote:

It is very similar to OpenMP, which was extended recently. I assume OpenACC also may want to add some new features here later

https://github.com/llvm/llvm-project/pull/73015