Index: include/llvm/Option/OptTable.h
===================================================================
--- include/llvm/Option/OptTable.h
+++ include/llvm/Option/OptTable.h
@@ -166,9 +166,10 @@
   /// \param FlagsToInclude - If non-zero, only include options with any
   ///                         of these flags set.
   /// \param FlagsToExclude - Exclude options with any of these flags set.
-  void PrintHelp(raw_ostream &OS, const char *Name,
-                 const char *Title, unsigned FlagsToInclude,
-                 unsigned FlagsToExclude) const;
+  /// \param PrintUndocumented - Print options that don't have any help.
+  void PrintHelp(raw_ostream &OS, const char *Name, const char *Title,
+                 unsigned FlagsToInclude, unsigned FlagsToExclude,
+                 bool PrintUndocumented = false) const;
 
   void PrintHelp(raw_ostream &OS, const char *Name,
                   const char *Title, bool ShowHidden = false) const;
Index: lib/Option/OptTable.cpp
===================================================================
--- lib/Option/OptTable.cpp
+++ lib/Option/OptTable.cpp
@@ -295,6 +295,27 @@
   return Args;
 }
 
+static std::string getOptionAlias(const OptTable &Opts, OptSpecifier Id) {
+  const Option O = Opts.getOption(Id);
+  std::string Name;
+
+  if (O.getAlias().isValid()) {
+    Name += O.getAlias().getPrefixedName();
+    if (O.getAliasArgs()) {
+      const char *Val = O.getAliasArgs();
+      const char *ArgSeparator = "";
+      while (*Val != '\0') {
+        Name += ArgSeparator;
+        Name += Val;
+        // Move past the '\0' to the next argument.
+        Val += strlen(Val) + 1;
+        ArgSeparator = " ";
+      }
+    }
+  }
+  return Name;
+}
+
 static std::string getOptionHelpName(const OptTable &Opts, OptSpecifier Id) {
   const Option O = Opts.getOption(Id);
   std::string Name = O.getPrefixedName();
@@ -319,6 +340,12 @@
     break;
 
   case Option::FlagClass:
+    if (O.getAlias().isValid()) {
+      const std::string Alias = getOptionAlias(Opts, Id);
+      assert(!Alias.empty() && "Valid but empty alias.");
+      Name += " | ";
+      Name += Alias;
+    }
     break;
 
   case Option::SeparateClass: case Option::JoinedOrSeparateClass:
@@ -361,9 +388,11 @@
     int Pad = OptionFieldWidth - int(Option.size());
     OS.indent(InitialPad) << Option;
 
-    // Break on long option names.
+    // Break on long option names if there's a help string to print.
     if (Pad < 0) {
-      OS << "\n";
+      if (strlen(OptionHelp[i].second) > 0) {
+        OS << "\n";
+      }
       Pad = OptionFieldWidth + InitialPad;
     }
     OS.indent(Pad + 1) << OptionHelp[i].second << '\n';
@@ -394,10 +423,9 @@
             (ShowHidden ? 0 : HelpHidden));
 }
 
-
 void OptTable::PrintHelp(raw_ostream &OS, const char *Name, const char *Title,
-                         unsigned FlagsToInclude,
-                         unsigned FlagsToExclude) const {
+                         unsigned FlagsToInclude, unsigned FlagsToExclude,
+                         bool PrintUndocumented) const {
   OS << "OVERVIEW: " << Title << "\n";
   OS << '\n';
   OS << "USAGE: " << Name << " [options] <inputs>\n";
@@ -422,10 +450,25 @@
     if (Flags & FlagsToExclude)
       continue;
 
-    if (const char *Text = getOptionHelpText(Id)) {
+    const char *HelpText = getOptionHelpText(Id);
+
+    if (!HelpText && PrintUndocumented) {
+      switch (getOptionKind(Id)) {
+      case Option::GroupClass:
+      case Option::InputClass:
+      case Option::UnknownClass:
+        // These option kinds are not supposed to be printed even now.
+        break;
+      default:
+        // For other options without help, fake an empty help string.
+        HelpText = "";
+      }
+    }
+
+    if (HelpText) {
       const char *HelpGroup = getOptionHelpGroup(*this, Id);
       const std::string &OptName = getOptionHelpName(*this, Id);
-      GroupedOptionHelp[HelpGroup].push_back(std::make_pair(OptName, Text));
+      GroupedOptionHelp[HelpGroup].push_back(std::make_pair(OptName, HelpText));
     }
   }