Added a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106063 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 897a19d..4705a0e 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2353,6 +2353,11 @@
 
     if (!WScope->getParent()) {
       StringRef SPName = DISubprogram(Scope).getLinkageName();
+      // We used to check only for a linkage name, but that fails
+      // since we began omitting the linkage name for private
+      // functions.  The new way is to check for the name in metadata,
+      // but that's not supported in old .ll test cases.  Ergo, we
+      // check both.
       if (SPName == Asm->MF->getFunction()->getName() ||
           DISubprogram(Scope).getFunction() == Asm->MF->getFunction())
         CurrentFnDbgScope = WScope;