[HLSL] Warn about incomplete language support (#108894)

This adds a warning about incomplete language mode support before HLSL
202x. This is the last change in the sequence to fix and make HLSL 202x
the default mode for Clang (#108044).


Fixes #108044

1 files changed, 9 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index de6776b..efd8525 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -4484,6 +4484,15 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
       }
     } else
       Diags.Report(diag::err_drv_hlsl_unsupported_target) << T.str();
+
+    if (Opts.LangStd < LangStandard::lang_hlsl202x) {
+      const LangStandard &Requested =
+          LangStandard::getLangStandardForKind(Opts.LangStd);
+      const LangStandard &Recommended =
+          LangStandard::getLangStandardForKind(LangStandard::lang_hlsl202x);
+      Diags.Report(diag::warn_hlsl_langstd_minimal)
+          << Requested.getName() << Recommended.getName();
+    }
   }
 
   return Diags.getNumErrors() == NumErrorsBefore;