diff --git a/clang/lib/Tooling/CommonOptionsParser.cpp b/clang/lib/Tooling/CommonOptionsParser.cpp
--- a/clang/lib/Tooling/CommonOptionsParser.cpp
+++ b/clang/lib/Tooling/CommonOptionsParser.cpp
@@ -83,8 +83,6 @@
 llvm::Error CommonOptionsParser::init(
     int &argc, const char **argv, cl::OptionCategory &Category,
     llvm::cl::NumOccurrencesFlag OccurrencesFlag, const char *Overview) {
-  static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden,
-                            cl::sub(*cl::AllSubCommands));
 
   static cl::opt<std::string> BuildPath("p", cl::desc("Build path"),
                                         cl::Optional, cl::cat(Category),
diff --git a/llvm/docs/CommandLine.rst b/llvm/docs/CommandLine.rst
--- a/llvm/docs/CommandLine.rst
+++ b/llvm/docs/CommandLine.rst
@@ -128,6 +128,7 @@
   USAGE: compiler [options]
 
   OPTIONS:
+    -h                - Alias for -help
     -help             - display available options (-help-hidden for more)
     -o <filename>     - Specify output filename
 
@@ -194,6 +195,7 @@
   USAGE: compiler [options] <input file>
 
   OPTIONS:
+    -h                - Alias for -help
     -help             - display available options (-help-hidden for more)
     -o <filename>     - Specify output filename
 
@@ -1251,6 +1253,14 @@
   with ``cl::CommaSeparated``, this modifier only makes sense with a `cl::list`_
   option.
 
+.. _cl::DefaultOption:
+
+* The **cl::DefaultOption** modifier is used to specify that the option is a
+  default that can be overridden by application specific parsers. For example,
+  the ``-help`` alias, ``-h``, is registered this way, so it can be overridden
+  by applications that need to use the ``-h`` option for another purpose,
+  either as a regular option or an alias for another option.
+
 .. _response files:
 
 Response files
diff --git a/llvm/include/llvm/Support/CommandLine.h b/llvm/include/llvm/Support/CommandLine.h
--- a/llvm/include/llvm/Support/CommandLine.h
+++ b/llvm/include/llvm/Support/CommandLine.h
@@ -175,7 +175,10 @@
   // If this is enabled, multiple letter options are allowed to bunch together
   // with only a single hyphen for the whole group.  This allows emulation
   // of the behavior that ls uses for example: ls -la === ls -l -a
-  Grouping = 0x08
+  Grouping = 0x08,
+
+  // Default option
+  DefaultOption = 0x10
 };
 
 //===----------------------------------------------------------------------===//
@@ -231,6 +234,7 @@
   SmallVector<Option *, 4> PositionalOpts;
   SmallVector<Option *, 4> SinkOpts;
   StringMap<Option *> OptionsMap;
+  SmallVector<std::string, 4> DefaultOptions;
 
   Option *ConsumeAfterOpt = nullptr; // The ConsumeAfter option if it exists.
 };
@@ -270,7 +274,7 @@
   unsigned Value : 2;
   unsigned HiddenFlag : 2; // enum OptionHidden
   unsigned Formatting : 2; // enum FormattingFlags
-  unsigned Misc : 4;
+  unsigned Misc : 5;
   unsigned Position = 0;       // Position of last occurrence of the option
   unsigned AdditionalVals = 0; // Greater than 0 for multi-valued option.
 
diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -144,6 +144,13 @@
   }
 
   void addOption(Option *O, SubCommand *SC) {
+    // Handle DefaultOptions
+    if (O->getMiscFlags() & cl::DefaultOption) {
+      std::string DefaultArg(O->ArgStr.str() + ":default_option");
+      SC->DefaultOptions.push_back(DefaultArg);
+      O->setArgStr(SC->DefaultOptions.back());
+    }
+
     bool HadErrors = false;
     if (O->hasArgStr()) {
       // Add argument to the argument map!
@@ -1167,6 +1174,22 @@
   auto &SinkOpts = ChosenSubCommand->SinkOpts;
   auto &OptionsMap = ChosenSubCommand->OptionsMap;
 
+  // Handle DefaultOptions.
+  for (auto const &DA : ChosenSubCommand->DefaultOptions) {
+    StringRef Arg(DA);
+    StringRef Val;
+    if (Option *Opt = LookupOption(*ChosenSubCommand, Arg, Val)) {
+      StringRef NewArg = Arg.substr(0, Arg.find(":"));
+      if (LookupOption(*ChosenSubCommand, NewArg, Val)) {
+        removeOption(Opt, ChosenSubCommand);
+      } else {
+        // FIXME: This is needed, but not sure why.
+        updateArgStr(Opt, NewArg, ChosenSubCommand);
+        Opt->setArgStr(NewArg);
+      }
+    }
+  }
+
   if (ConsumeAfterOpt) {
     assert(PositionalOpts.size() > 0 &&
            "Cannot specify cl::ConsumeAfter without a positional argument!");
@@ -2146,6 +2169,10 @@
         cl::location(WrappedNormalPrinter), cl::ValueDisallowed,
         cl::cat(GenericCategory), cl::sub(*AllSubCommands));
 
+static cl::alias HOpA("h", cl::desc("Alias for -help"), cl::aliasopt(HOp),
+                      cl::cat(GenericCategory), cl::sub(*AllSubCommands),
+                      cl::DefaultOption);
+
 static cl::opt<HelpPrinterWrapper, true, parser<bool>>
     HHOp("help-hidden", cl::desc("Display all available options"),
          cl::location(WrappedHiddenPrinter), cl::Hidden, cl::ValueDisallowed,