[Option] Plug a leak when move-assigning an InputArgList.

The class has a non-trivial dtor so we have to clean up before we move
in new members. Remove misleading comment as a default move assignment
operator will never be synthesized for this class.

llvm-svn: 240417

llvm/include/llvm/Option/ArgList.h

@@ -325,22 +325,24 @@ private:
   /// The number of original input argument strings.
   unsigned NumInputArgStrings;
 
+  /// Release allocated arguments.
+  void releaseMemory();
+
 public:
   InputArgList(const char* const *ArgBegin, const char* const *ArgEnd);
-  // Default move operations implemented for the convenience of MSVC. Nothing
-  // special here.
   InputArgList(InputArgList &&RHS)
       : ArgList(std::move(RHS)), ArgStrings(std::move(RHS.ArgStrings)),
         SynthesizedStrings(std::move(RHS.SynthesizedStrings)),
         NumInputArgStrings(RHS.NumInputArgStrings) {}
   InputArgList &operator=(InputArgList &&RHS) {
+    releaseMemory();
     ArgList::operator=(std::move(RHS));
     ArgStrings = std::move(RHS.ArgStrings);
     SynthesizedStrings = std::move(RHS.SynthesizedStrings);
     NumInputArgStrings = RHS.NumInputArgStrings;
     return *this;
   }
-  ~InputArgList();
+  ~InputArgList() { releaseMemory(); }
 
   const char *getArgString(unsigned Index) const override {
     return ArgStrings[Index];

llvm/lib/Option/ArgList.cpp

@@ -315,18 +315,18 @@ const char *ArgList::GetOrMakeJoinedArgString(unsigned Index,
 
 //
 
+void InputArgList::releaseMemory() {
+  // An InputArgList always owns its arguments.
+  for (Arg *A : *this)
+    delete A;
+}
+
 InputArgList::InputArgList(const char* const *ArgBegin,
                            const char* const *ArgEnd)
   : NumInputArgStrings(ArgEnd - ArgBegin) {
   ArgStrings.append(ArgBegin, ArgEnd);
 }
 
-InputArgList::~InputArgList() {
-  // An InputArgList always owns its arguments.
-  for (iterator it = begin(), ie = end(); it != ie; ++it)
-    delete *it;
-}
-
 unsigned InputArgList::MakeIndex(StringRef String0) const {
   unsigned Index = ArgStrings.size();