Protect the ArgList dtor

It could even be made non-virtual if it weren't for bad compiler
warnings.

This demonstrates that ArgList objects aren't destroyed polymorphically
and possibly that they aren't even used polymorphically. If that's the
case, it might be possible to refactor the two ArgList types more
separately and simplify the Arg ownership model. *continues
experimenting*

llvm-svn: 206727

2 files changed, 6 insertions, 7 deletions

diff --git a/llvm/include/llvm/Option/ArgList.h b/llvm/include/llvm/Option/ArgList.h
index 25248f444dd..ab40a1a0d40 100644
--- a/llvm/include/llvm/Option/ArgList.h
+++ b/llvm/include/llvm/Option/ArgList.h
@@ -106,10 +106,14 @@ private:
   arglist_type Args;
 
 protected:
-  ArgList();
+  // Default ctor provided explicitly as it is not provided implicitly due to
+  // the presence of the (deleted) copy ctor above.
+  ArgList() { }
+  // Virtual to provide a vtable anchor and because -Wnon-virtua-dtor warns, not
+  // because this type is ever actually destroyed polymorphically.
+  virtual ~ArgList();
 
 public:
-  virtual ~ArgList();
 
   /// @name Arg Access
   /// @{
diff --git a/llvm/lib/Option/ArgList.cpp b/llvm/lib/Option/ArgList.cpp
index 2d65c5ac870..1f16331e079 100644
--- a/llvm/lib/Option/ArgList.cpp
+++ b/llvm/lib/Option/ArgList.cpp
@@ -33,11 +33,6 @@ void arg_iterator::SkipToNextArg() {
   }
 }
 
-//
-
-ArgList::ArgList() {
-}
-
 ArgList::~ArgList() {
 }