[SYCL] Tweak v-table suppress patch to work with virtual host calls

The previous fix skipped template instantiations where virtual calls
were involved, causing kernel functions used in these base classes to
never be discovered, and thus skipped.

This patch moves it simply to prevent virtual tables from being emitted,
leaving the walking and instantiation of templates in place.

Signed-off-by: Vladimir Lazarev <[email protected]>

Author: vladimirlaz

clang/lib/CodeGen/ModuleBuilder.cpp

@@ -284,6 +284,10 @@ namespace {
       if (Diags.hasErrorOccurred())
         return;
 
+      // No VTable usage is legal in SYCL, so don't bother marking them used.
+      if (Ctx->getLangOpts().SYCL)
+        return;
+
       Builder->EmitVTable(RD);
     }
   };

clang/lib/Sema/SemaDeclCXX.cpp

@@ -15013,10 +15013,6 @@ void Sema::MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
     return;
   }
 
-  // No VTable usage is legal in SYCL, so don't bother marking them used.
-  if (getLangOpts().SYCL)
-    return;
-
   // Try to insert this class into the map.
   LoadExternalVTableUses();
   Class = Class->getCanonicalDecl();