Support: Fix option handling when using cl::Required with aliasopt

Until now, attempting to create an alias of a required option would
complain if the user supplied the alias, because the required option
didn't have a value. Similarly, if you said the alias was required,
then using the base option would complain that the alias wasn't
supplied. Lastly, if you put required on both, *neither* option would
work.

By changning alias to overload addOccurrence and setting cl::Required
on the original option, we can get this to behave in a more useful
way. I've also added a test and updated a user that was getting this
wrong.

llvm-svn: 212986

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/include/llvm/Support/CommandLine.h b/llvm/include/llvm/Support/CommandLine.h
index 5cb55013973..fdd901200fe 100644
--- a/llvm/include/llvm/Support/CommandLine.h
+++ b/llvm/include/llvm/Support/CommandLine.h
@@ -270,8 +270,8 @@ public:
 
   // addOccurrence - Wrapper around handleOccurrence that enforces Flags.
   //
-  bool addOccurrence(unsigned pos, StringRef ArgName,
-                     StringRef Value, bool MultiArg = false);
+  virtual bool addOccurrence(unsigned pos, StringRef ArgName,
+                             StringRef Value, bool MultiArg = false);
 
   // Prints option name followed by message.  Always returns true.
   bool error(const Twine &Message, StringRef ArgName = StringRef());
@@ -1649,6 +1649,10 @@ class alias : public Option {
                                 StringRef Arg) override {
     return AliasFor->handleOccurrence(pos, AliasFor->ArgStr, Arg);
   }
+  bool addOccurrence(unsigned pos, StringRef /*ArgName*/,
+                     StringRef Value, bool MultiArg = false) override {
+    return AliasFor->addOccurrence(pos, AliasFor->ArgStr, Value, MultiArg);
+  }
   // Handle printing stuff...
   size_t getOptionWidth() const override;
   void printOptionInfo(size_t GlobalWidth) const override;