1 files changed, 28 insertions, 5 deletions

diff --git a/include/llvm/Support/CommandLine.h b/include/llvm/Support/CommandLine.h
index 71d2f02930831..d1901db7c68e7 100644
--- a/include/llvm/Support/CommandLine.h
+++ b/include/llvm/Support/CommandLine.h
@@ -66,12 +66,15 @@ bool ParseCommandLineOptions(int argc, const char *const *argv,
 void ParseEnvironmentOptions(const char *progName, const char *envvar,
                              const char *Overview = "");
 
+// Function pointer type for printing version information.
+using VersionPrinterTy = std::function<void(raw_ostream &)>;
+
 ///===---------------------------------------------------------------------===//
 /// SetVersionPrinter - Override the default (LLVM specific) version printer
 ///                     used to print out the version when --version is given
 ///                     on the command line. This allows other systems using the
 ///                     CommandLine utilities to print their own version string.
-void SetVersionPrinter(void (*func)());
+void SetVersionPrinter(VersionPrinterTy func);
 
 ///===---------------------------------------------------------------------===//
 /// AddExtraVersionPrinter - Add an extra printer to use in addition to the
@@ -80,7 +83,7 @@ void SetVersionPrinter(void (*func)());
 ///                          which will be called after the basic LLVM version
 ///                          printing is complete. Each can then add additional
 ///                          information specific to the tool.
-void AddExtraVersionPrinter(void (*func)());
+void AddExtraVersionPrinter(VersionPrinterTy func);
 
 // PrintOptionValues - Print option values.
 // With -print-options print the difference between option values and defaults.
@@ -263,7 +266,7 @@ public:
   StringRef ValueStr; // String describing what the value of this option is
   OptionCategory *Category; // The Category this option belongs to
   SmallPtrSet<SubCommand *, 4> Subs; // The subcommands this option belongs to.
-  bool FullyInitialized = false; // Has addArguemnt been called?
+  bool FullyInitialized = false; // Has addArgument been called?
 
   inline enum NumOccurrencesFlag getNumOccurrencesFlag() const {
     return (enum NumOccurrencesFlag)Occurrences;
@@ -346,6 +349,8 @@ public:
 
   virtual void printOptionValue(size_t GlobalWidth, bool Force) const = 0;
 
+  virtual void setDefault() = 0;
+
   static void printHelpStr(StringRef HelpStr, size_t Indent,
                            size_t FirstLineIndentedBy);
 
@@ -1315,6 +1320,20 @@ class opt : public Option,
     }
   }
 
+  template <class T, class = typename std::enable_if<
+            std::is_assignable<T&, T>::value>::type>
+  void setDefaultImpl() {
+    const OptionValue<DataType> &V = this->getDefault();
+    if (V.hasValue())
+      this->setValue(V.getValue());
+  }
+
+  template <class T, class = typename std::enable_if<
+            !std::is_assignable<T&, T>::value>::type>
+  void setDefaultImpl(...) {}
+
+  void setDefault() override { setDefaultImpl<DataType>(); }
+
   void done() {
     addArgument();
     Parser.initialize();
@@ -1490,6 +1509,8 @@ class list : public Option, public list_storage<DataType, StorageClass> {
   void printOptionValue(size_t /*GlobalWidth*/, bool /*Force*/) const override {
   }
 
+  void setDefault() override {}
+
   void done() {
     addArgument();
     Parser.initialize();
@@ -1631,6 +1652,8 @@ class bits : public Option, public bits_storage<DataType, Storage> {
   void printOptionValue(size_t /*GlobalWidth*/, bool /*Force*/) const override {
   }
 
+  void setDefault() override {}
+
   void done() {
     addArgument();
     Parser.initialize();
@@ -1681,6 +1704,8 @@ class alias : public Option {
   void printOptionValue(size_t /*GlobalWidth*/, bool /*Force*/) const override {
   }
 
+  void setDefault() override { AliasFor->setDefault(); }
+
   ValueExpected getValueExpectedFlagDefault() const override {
     return AliasFor->getValueExpectedFlag();
   }
@@ -1737,8 +1762,6 @@ void PrintVersionMessage();
 /// This function just prints the help message, exactly the same way as if the
 /// -help or -help-hidden option had been given on the command line.
 ///
-/// NOTE: THIS FUNCTION TERMINATES THE PROGRAM!
-///
 /// \param Hidden if true will print hidden options
 /// \param Categorized if true print options in categories
 void PrintHelpMessage(bool Hidden = false, bool Categorized = false);