[OptDiag] Hide legacy remark ctors

These are only used when emitting remarks without ORE directly using the free
functions emitOptimizationRemark*.

llvm-svn: 296037
diff --git a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
index c645721..6b9bfc0 100644
--- a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
+++ b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
@@ -896,7 +896,11 @@
   if (FL.empty())
     return false;
   const Function &Fn = FL.front();
-  auto DI = OptimizationRemark(DEBUG_TYPE, Fn, DebugLoc(), "");
+
+  const auto &BBL = Fn.getBasicBlockList();
+  if (BBL.empty())
+    return false;
+  auto DI = OptimizationRemark(DEBUG_TYPE, "", DebugLoc(), &BBL.front());
   return DI.isEnabled();
 }