[CommandLine] Change help output to prefix long options with `--` instead of `-`. NFC . Part 3 of 5

[hintonda]

Summary

By default, parseCommandLineOptions() will accept either a
- or -- prefix for long options -- options with names longer than
a single character.

While this change does not affect behavior, it will be helpful with a
subsequent change that requires long options use the -- prefix.

[hintonda]

• Fix dashes for help on error.

[hintonda]

• Fix dashes in error messages and in tests.

[thopre]

llvm/lib/Support/CommandLine.cpp

95 ↗

(On Diff #197267)

Any reason why not take a StringRef of the option to compute the prefix of? That would put the .size() gymnastic in one place instead of many.

101 ↗

(On Diff #197267)

Likewise.

[hintonda]

llvm/lib/Support/CommandLine.cpp

95 ↗

(On Diff #197267)

Actually, that's what I originally had, but since it was only a few places, I changed it to take the length. Now that I see it's used all over, I'll probably switch it back as you suggest.

[hintonda]

• Refactor and fix additional dashes in error messages and tests.

[thopre]

That's much better thank you. I like the stream shift operator overload, nice touch. LGTM but give it a day for other to give feedback.

[thakis]

I happened to see this go by. Is there an explanation of the overall goal somewhere? In general, requiring -- for long flags sounds like a great change to me, but there are a few exceptions: For example. lld-link should keep accepting long flags with a single dash for link.exe compatibility.

[hintonda]

In D61269#1490176, @thakis wrote:

I happened to see this go by. Is there an explanation of the overall goal somewhere? In general, requiring -- for long flags sounds like a great change to me, but there are a few exceptions: For example. lld-link should keep accepting long flags with a single dash for link.exe compatibility.

The 5th and final patch, D61294, "[CommandLine] Add long option flag for cl::ParseCommandLineOptions . Part 5 of 5", adds a flag that requires long options use the --. It's an opt-in strategy, so only tools that want the GNU getopt_long behavior would want to set it. Otherwise, everything works the way it does currently, with the exception of help printing -- for long options.

As noted in D61294, these changes were motivated by this discussion: http://lists.llvm.org/pipermail/llvm-dev/2019-April/131786.html

Of course, this doesn't change tblgen generated options which are a different animal.

[thakis]

Thanks for the context. Sounds great :)

cfe/trunk/test/Driver/clang-offload-bundler.c

 // RUN: not clang-offload-bundler -type=i -targets=host-powerpc64le-ibm-linux-gnu,openmp-powerpc64le-ibm-linux-gnu,openmp-x86_64-pc-linux-gnu -inputs=%t.i,%t.tgt1,%t.tgt2.notexist -outputs=%t.bundle.i 2>&1 | FileCheck %s --check-prefix CK-ERR5
 // RUN: not clang-offload-bundler -type=i -targets=host-powerpc64le-ibm-linux-gnu,openmp-powerpc64le-ibm-linux-gnu,openmp-x86_64-pc-linux-gnu -outputs=%t.i,%t.tgt1,%t.tgt2 -inputs=%t.bundle.i.notexist -unbundle 2>&1 | FileCheck %s --check-prefix CK-ERR5
 // CK-ERR5: error: Can't open file {{.+}}.notexist: {{N|n}}o such file or directory
 
 // RUN: not clang-offload-bundler -type=invalid -targets=host-powerpc64le-ibm-linux-gnu,openmp-powerpc64le-ibm-linux-gnu,openmp-x86_64-pc-linux-gnu -inputs=%t.i,%t.tgt1,%t.tgt2 -outputs=%t.bundle.i 2>&1 | FileCheck %s --check-prefix CK-ERR6
 // CK-ERR6: error: invalid file type specified.
 
 // RUN: not clang-offload-bundler 2>&1 | FileCheck %s --check-prefix CK-ERR7
-// CK-ERR7-DAG: clang-offload-bundler: for the -type option: must be specified at least once!
-// CK-ERR7-DAG: clang-offload-bundler: for the -inputs option: must be specified at least once!
-// CK-ERR7-DAG: clang-offload-bundler: for the -outputs option: must be specified at least once!
-// CK-ERR7-DAG: clang-offload-bundler: for the -targets option: must be specified at least once!
+// CK-ERR7-DAG: clang-offload-bundler: for the --type option: must be specified at least once!
+// CK-ERR7-DAG: clang-offload-bundler: for the --inputs option: must be specified at least once!
+// CK-ERR7-DAG: clang-offload-bundler: for the --outputs option: must be specified at least once!
+// CK-ERR7-DAG: clang-offload-bundler: for the --targets option: must be specified at least once!
 
 // RUN: not clang-offload-bundler -type=i -targets=hxst-powerpcxxle-ibm-linux-gnu,openxp-pxxerpc64le-ibm-linux-gnu,xpenmp-x86_xx-pc-linux-gnu -inputs=%t.i,%t.tgt1,%t.tgt2 -outputs=%t.bundle.i 2>&1 | FileCheck %s --check-prefix CK-ERR8
 // CK-ERR8: error: invalid target 'hxst-powerpcxxle-ibm-linux-gnu', unknown offloading kind 'hxst', unknown target triple 'powerpcxxle-ibm-linux-gnu'.
 // CK-ERR8: error: invalid target 'openxp-pxxerpc64le-ibm-linux-gnu', unknown offloading kind 'openxp', unknown target triple 'pxxerpc64le-ibm-linux-gnu'.
 // CK-ERR8: error: invalid target 'xpenmp-x86_xx-pc-linux-gnu', unknown offloading kind 'xpenmp', unknown target triple 'x86_xx-pc-linux-gnu'.
 
 // RUN: not clang-offload-bundler -type=i -targets=openmp-powerpc64le-linux,openmp-powerpc64le-ibm-linux-gnu,openmp-x86_64-pc-linux-gnu -inputs=%t.i,%t.tgt1,%t.tgt2 -outputs=%t.bundle.i 2>&1 | FileCheck %s --check-prefix CK-ERR9A
 // RUN: not clang-offload-bundler -type=i -targets=host-powerpc64le-ibm-linux-gnu,host-powerpc64le-ibm-linux-gnu,openmp-x86_64-pc-linux-gnu -inputs=%t.i,%t.tgt1,%t.tgt2 -outputs=%t.bundle.i 2>&1 | FileCheck %s --check-prefix CK-ERR9B

llvm/trunk/lib/Support/CommandLine.cpp

 void parser<unsigned long long>::anchor() {}
 void parser<double>::anchor() {}
 void parser<float>::anchor() {}
 void parser<std::string>::anchor() {}
 void parser<char>::anchor() {}
 
 //===----------------------------------------------------------------------===//
 
+static StringRef ArgPrefix = "  -";
+static StringRef ArgPrefixLong = "  --";
+static StringRef ArgHelpPrefix = " - ";
+
+static size_t argPlusPrefixesSize(StringRef ArgName) {
+  size_t Len = ArgName.size();
+  if (Len == 1)
+    return Len + ArgPrefix.size() + ArgHelpPrefix.size();
+  return Len + ArgPrefixLong.size() + ArgHelpPrefix.size();
+}
+
+static StringRef argPrefix(StringRef ArgName) {
+  if (ArgName.size() == 1)
+    return ArgPrefix;
+  return ArgPrefixLong;
+}
+
 namespace {
 
+class PrintArg {
+  StringRef ArgName;
+public:
+  PrintArg(StringRef ArgName) : ArgName(ArgName) {}
+  friend raw_ostream &operator<<(raw_ostream &OS, const PrintArg&);
+};
+
+raw_ostream &operator<<(raw_ostream &OS, const PrintArg& Arg) {
+  OS << argPrefix(Arg.ArgName) << Arg.ArgName;
+  return OS;
+}
+
 class CommandLineParser {
 public:
   // Globals for name and overview of program.  Program name is not a string to
   // avoid static ctor/dtor issues.
   std::string ProgramName;
   StringRef ProgramOverview;
 
   // This collects additional help to be printed.
if (argv[i][0] != '-' || argv[i][1] == 0 || DashDashFound) {
       if (!Handler && SinkOpts.empty())
         NearestHandler =
             LookupNearestOption(ArgName, OptionsMap, NearestHandlerString);
     }
 
     if (!Handler) {
       if (SinkOpts.empty()) {
         *Errs << ProgramName << ": Unknown command line argument '" << argv[i]
-              << "'.  Try: '" << argv[0] << " -help'\n";
+              << "'.  Try: '" << argv[0] << " --help'\n";
 
         if (NearestHandler) {
           // If we know a near match, report it as well.
-          *Errs << ProgramName << ": Did you mean '-" << NearestHandlerString
-                 << "'?\n";
+          *Errs << ProgramName << ": Did you mean '"
+                << PrintArg(NearestHandlerString) << "'?\n";
         }
 
         ErrorParsing = true;
       } else {
         for (SmallVectorImpl<Option *>::iterator I = SinkOpts.begin(),
                                                  E = SinkOpts.end();
              I != E; ++I)
           (*I)->addOccurrence(i, "", StringRef(argv[i]));
bool CommandLineParser::ParseCommandLineOptions(int argc,
   }
 
   // Check and handle positional arguments now...
   if (NumPositionalRequired > PositionalVals.size()) {
       *Errs << ProgramName
              << ": Not enough positional command line arguments specified!\n"
              << "Must specify at least " << NumPositionalRequired
              << " positional argument" << (NumPositionalRequired > 1 ? "s" : "")
-             << ": See: " << argv[0] << " -help\n";
+             << ": See: " << argv[0] << " --help\n";
 
     ErrorParsing = true;
   } else if (!HasUnlimitedPositionals &&
              PositionalVals.size() > PositionalOpts.size()) {
     *Errs << ProgramName << ": Too many positional arguments specified!\n"
           << "Can specify at most " << PositionalOpts.size()
-          << " positional arguments: See: " << argv[0] << " -help\n";
+          << " positional arguments: See: " << argv[0] << " --help\n";
     ErrorParsing = true;
 
   } else if (!ConsumeAfterOpt) {
     // Positional args have already been handled if ConsumeAfter is specified.
     unsigned ValNo = 0, NumVals = static_cast<unsigned>(PositionalVals.size());
     for (size_t i = 0, e = PositionalOpts.size(); i != e; ++i) {
       if (RequiresValue(PositionalOpts[i])) {
         ProvidePositionalOption(PositionalOpts[i], PositionalVals[ValNo].first,

 //
 
 bool Option::error(const Twine &Message, StringRef ArgName, raw_ostream &Errs) {
   if (!ArgName.data())
     ArgName = ArgStr;
   if (ArgName.empty())
     Errs << HelpStr; // Be nice for positional arguments
   else
-    Errs << GlobalParser->ProgramName << ": for the -" << ArgName;
+    Errs << GlobalParser->ProgramName << ": for the " << PrintArg(ArgName);
 
   Errs << " option: " << Message << "\n";
   return true;
 }
 
 bool Option::addOccurrence(unsigned pos, StringRef ArgName, StringRef Value,
                            bool MultiArg) {
   if (!MultiArg)

 // has been specified yet.
 //
 static StringRef getValueStr(const Option &O, StringRef DefaultMsg) {
   if (O.ValueStr.empty())
     return DefaultMsg;
   return O.ValueStr;
 }
 
-static StringRef ArgPrefix = "  -";
-static StringRef ArgHelpPrefix = " - ";
-static size_t ArgPrefixesSize = ArgPrefix.size() + ArgHelpPrefix.size();
-
 //===----------------------------------------------------------------------===//
 // cl::alias class implementation
 //
 
 // Return the width of the option tag for printing...
-size_t alias::getOptionWidth() const { return ArgStr.size() + ArgPrefixesSize; }
+size_t alias::getOptionWidth() const {
+  return argPlusPrefixesSize(ArgStr);
+}
 
 void Option::printHelpStr(StringRef HelpStr, size_t Indent,
                           size_t FirstLineIndentedBy) {
   assert(Indent >= FirstLineIndentedBy);
   std::pair<StringRef, StringRef> Split = HelpStr.split('\n');
   outs().indent(Indent - FirstLineIndentedBy)
       << ArgHelpPrefix << Split.first << "\n";
   while (!Split.second.empty()) {
     Split = Split.second.split('\n');
     outs().indent(Indent) << Split.first << "\n";
   }
 }
 
 // Print out the option for the alias.
 void alias::printOptionInfo(size_t GlobalWidth) const {
-  outs() << ArgPrefix << ArgStr;
-  printHelpStr(HelpStr, GlobalWidth, ArgStr.size() + ArgPrefixesSize);
+  outs() << PrintArg(ArgStr);
+  printHelpStr(HelpStr, GlobalWidth, argPlusPrefixesSize(ArgStr));
 }
 
 //===----------------------------------------------------------------------===//
 // Parser Implementation code...
 //
 
 // basic_parser implementation
 //
 
 // Return the width of the option tag for printing...
 size_t basic_parser_impl::getOptionWidth(const Option &O) const {
-  size_t Len = O.ArgStr.size();
+  size_t Len = argPlusPrefixesSize(O.ArgStr);
   auto ValName = getValueName();
   if (!ValName.empty()) {
     size_t FormattingLen = 3;
     if (O.getMiscFlags() & PositionalEatsArgs)
       FormattingLen = 6;
     Len += getValueStr(O, ValName).size() + FormattingLen;
   }
 
-  return Len + ArgPrefixesSize;
+  return Len;
 }
 
 // printOptionInfo - Print out information about this option.  The
 // to-be-maintained width is specified.
 //
 void basic_parser_impl::printOptionInfo(const Option &O,
                                         size_t GlobalWidth) const {
-  outs() << ArgPrefix << O.ArgStr;
+  outs() << PrintArg(O.ArgStr);
 
   auto ValName = getValueName();
   if (!ValName.empty()) {
     if (O.getMiscFlags() & PositionalEatsArgs) {
       outs() << " <" << getValueStr(O, ValName) << ">...";
     } else {
       outs() << "=<" << getValueStr(O, ValName) << '>';
     }
   }
 
   Option::printHelpStr(O.HelpStr, GlobalWidth, getOptionWidth(O));
 }
 
 void basic_parser_impl::printOptionName(const Option &O,
                                         size_t GlobalWidth) const {
-  outs() << ArgPrefix << O.ArgStr;
+  outs() << PrintArg(O.ArgStr);
   outs().indent(GlobalWidth - O.ArgStr.size());
 }
 
 // parser<bool> implementation
 //
 bool parser<bool>::parse(Option &O, StringRef ArgName, StringRef Arg,
                          bool &Value) {
   if (Arg == "" || Arg == "true" || Arg == "TRUE" || Arg == "True" ||
static bool shouldPrintOption(StringRef Name, StringRef Description,
                               const Option &O) {
   return O.getValueExpectedFlag() != ValueOptional || !Name.empty() ||
          !Description.empty();
 }
 
 // Return the width of the option tag for printing...
 size_t generic_parser_base::getOptionWidth(const Option &O) const {
   if (O.hasArgStr()) {
-    size_t Size = O.ArgStr.size() + ArgPrefixesSize + EqValue.size();
+    size_t Size =
+        argPlusPrefixesSize(O.ArgStr) + EqValue.size();
     for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
       StringRef Name = getOption(i);
       if (!shouldPrintOption(Name, getDescription(i), O))
         continue;
       size_t NameSize = Name.empty() ? EmptyOption.size() : Name.size();
       Size = std::max(Size, NameSize + OptionPrefixesSize);
     }
     return Size;

 void generic_parser_base::printOptionInfo(const Option &O,
                                           size_t GlobalWidth) const {
   if (O.hasArgStr()) {
     // When the value is optional, first print a line just describing the
     // option without values.
     if (O.getValueExpectedFlag() == ValueOptional) {
       for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
         if (getOption(i).empty()) {
-          outs() << ArgPrefix << O.ArgStr;
+          outs() << PrintArg(O.ArgStr);
           Option::printHelpStr(O.HelpStr, GlobalWidth,
-                               O.ArgStr.size() + ArgPrefixesSize);
+                               argPlusPrefixesSize(O.ArgStr));
           break;
         }
       }
     }
 
-    outs() << ArgPrefix << O.ArgStr << EqValue;
+    outs() << PrintArg(O.ArgStr) << EqValue;
     Option::printHelpStr(O.HelpStr, GlobalWidth,
-                         O.ArgStr.size() + EqValue.size() + ArgPrefixesSize);
+                         EqValue.size() +
+                             argPlusPrefixesSize(O.ArgStr));
     for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
       StringRef OptionName = getOption(i);
       StringRef Description = getDescription(i);
       if (!shouldPrintOption(OptionName, Description, O))
         continue;
       assert(GlobalWidth >= OptionName.size() + OptionPrefixesSize);
       size_t NumSpaces = GlobalWidth - OptionName.size() - OptionPrefixesSize;
       outs() << OptionPrefix << OptionName;
       if (OptionName.empty()) {
         outs() << EmptyOption;
         assert(NumSpaces >= EmptyOption.size());
         NumSpaces -= EmptyOption.size();
       }
       if (!Description.empty())
         outs().indent(NumSpaces) << ArgHelpPrefix << "  " << Description;
       outs() << '\n';
     }
   } else {
     if (!O.HelpStr.empty())
       outs() << "  " << O.HelpStr << '\n';
     for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
-      auto Option = getOption(i);
-      outs() << "    -" << Option;
+      StringRef Option = getOption(i);
+      outs() << "    " << PrintArg(Option);
       Option::printHelpStr(getDescription(i), GlobalWidth, Option.size() + 8);
     }
   }
 }
 
 static const size_t MaxOptWidth = 8; // arbitrary spacing for printOptionDiff
 
 // printGenericOptionDiff - Print the value of this option and it's default.
 //
 // "Generic" options have each value mapped to a name.
 void generic_parser_base::printGenericOptionDiff(
     const Option &O, const GenericOptionValue &Value,
     const GenericOptionValue &Default, size_t GlobalWidth) const {
-  outs() << "  -" << O.ArgStr;
+  outs() << "  " << PrintArg(O.ArgStr);
   outs().indent(GlobalWidth - O.ArgStr.size());
 
   unsigned NumOpts = getNumOptions();
   for (unsigned i = 0; i != NumOpts; ++i) {
     if (Value.compare(getOptionValue(i)))
       continue;
 
     outs() << "= " << getOption(i);
if (Sub == &*TopLevelSubCommand && !Subs.empty()) {
       for (size_t i = 0, e = Subs.size(); i != e; ++i)
         MaxSubLen = std::max(MaxSubLen, strlen(Subs[i].first));
 
       outs() << "\n\n";
       outs() << "SUBCOMMANDS:\n\n";
       printSubCommands(Subs, MaxSubLen);
       outs() << "\n";
       outs() << "  Type \"" << GlobalParser->ProgramName
-             << " <subcommand> -help\" to get more help on a specific "
+             << " <subcommand> --help\" to get more help on a specific "
                 "subcommand";
     }
 
     outs() << "\n\n";
 
     // Compute the maximum argument length...
     size_t MaxArgLen = 0;
     for (size_t i = 0, e = Opts.size(); i != e; ++i)
for (size_t I = 0, E = Opts.size(); I != E; ++I) {
       CategorizedOptions[Opt->Category].push_back(Opt);
     }
 
     // Now do printing.
     for (std::vector<OptionCategory *>::const_iterator
              Category = SortedCategories.begin(),
              E = SortedCategories.end();
          Category != E; ++Category) {
-      // Hide empty categories for -help, but show for -help-hidden.
+      // Hide empty categories for --help, but show for --help-hidden.
       const auto &CategoryOptions = CategorizedOptions[*Category];
       bool IsEmptyCategory = CategoryOptions.empty();
       if (!ShowHidden && IsEmptyCategory)
         continue;
 
       // Print category information.
       outs() << "\n";
       outs() << (*Category)->getName() << ":\n";
 
       // Check if description is set.
       if (!(*Category)->getDescription().empty())
         outs() << (*Category)->getDescription() << "\n\n";
       else
         outs() << "\n";
 
-      // When using -help-hidden explicitly state if the category has no
+      // When using --help-hidden explicitly state if the category has no
       // options associated with it.
       if (IsEmptyCategory) {
         outs() << "  This option category has no options.\n";
         continue;
       }
       // Loop over the options in the category and print.
       for (const Option *Opt : CategoryOptions)
         Opt->printOptionInfo(MaxArgLen);
static HelpPrinterWrapper WrappedNormalPrinter(UncategorizedNormalPrinter,
                                                CategorizedNormalPrinter);
 static HelpPrinterWrapper WrappedHiddenPrinter(UncategorizedHiddenPrinter,
                                                CategorizedHiddenPrinter);
 
 // Define a category for generic options that all tools should have.
 static cl::OptionCategory GenericCategory("Generic Options");
 
 // Define uncategorized help printers.
-// -help-list is hidden by default because if Option categories are being used
-// then -help behaves the same as -help-list.
+// --help-list is hidden by default because if Option categories are being used
+// then --help behaves the same as --help-list.
 static cl::opt<HelpPrinter, true, parser<bool>> HLOp(
     "help-list",
-    cl::desc("Display list of available options (-help-list-hidden for more)"),
+    cl::desc("Display list of available options (--help-list-hidden for more)"),
     cl::location(UncategorizedNormalPrinter), cl::Hidden, cl::ValueDisallowed,
     cl::cat(GenericCategory), cl::sub(*AllSubCommands));
 
 static cl::opt<HelpPrinter, true, parser<bool>>
     HLHOp("help-list-hidden", cl::desc("Display list of all available options"),
           cl::location(UncategorizedHiddenPrinter), cl::Hidden,
           cl::ValueDisallowed, cl::cat(GenericCategory),
           cl::sub(*AllSubCommands));
 
 // Define uncategorized/categorized help printers. These printers change their
 // behaviour at runtime depending on whether one or more Option categories have
 // been declared.
 static cl::opt<HelpPrinterWrapper, true, parser<bool>>
-    HOp("help", cl::desc("Display available options (-help-hidden for more)"),
+    HOp("help", cl::desc("Display available options (--help-hidden for more)"),
         cl::location(WrappedNormalPrinter), cl::ValueDisallowed,
         cl::cat(GenericCategory), cl::sub(*AllSubCommands));
 
-static cl::alias HOpA("h", cl::desc("Alias for -help"), cl::aliasopt(HOp),
+static cl::alias HOpA("h", cl::desc("Alias for --help"), cl::aliasopt(HOp),
                       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,
          cl::cat(GenericCategory), cl::sub(*AllSubCommands));
 
 static cl::opt<bool> PrintOptions(

 void HelpPrinterWrapper::operator=(bool Value) {
   if (!Value)
     return;
 
   // Decide which printer to invoke. If more than one option category is
   // registered then it is useful to show the categorized help instead of
   // uncategorized help.
   if (GlobalParser->RegisteredOptionCategories.size() > 1) {
-    // unhide -help-list option so user can have uncategorized output if they
+    // unhide --help-list option so user can have uncategorized output if they
     // want it.
     HLOp.setHiddenFlag(NotHidden);
 
     CategorizedPrinter = true; // Invoke categorized printer
   } else
     UncategorizedPrinter = true; // Invoke uncategorized printer
 }
 

llvm/trunk/test/FileCheck/dump-input-enable.txt

 ; RUN: not FileCheck -input-file %t.good %t.check -check-prefix=CHECK \
 ; RUN:               -match-full-lines -dump-input=foobar 2>&1 \
 ; RUN: | FileCheck %s -match-full-lines -check-prefix=BADVAL
 
 ; No positional arg.
 ; RUN: not FileCheck -dump-input=foobar 2>&1 \
 ; RUN: | FileCheck %s -match-full-lines -check-prefix=BADVAL
 
-BADVAL: {{F|f}}ile{{C|c}}heck{{.*}}: for the -dump-input option: Cannot find option named 'foobar'!
+BADVAL: {{F|f}}ile{{C|c}}heck{{.*}}: for the --dump-input option: Cannot find option named 'foobar'!
 
 ;--------------------------------------------------
 ; Check -dump-input=help.
 ;--------------------------------------------------
 
 ; Appended to normal command line.
 ; RUN: FileCheck -input-file %t.err -color %t.check -dump-input=help \
 ; RUN: | FileCheck %s -check-prefix=HELP

llvm/trunk/test/Support/check-default-options.txt

 # RUN: llvm-objdump --help-hidden %t | FileCheck --check-prefix=CHECK-OBJDUMP %s
 # RUN: llvm-readobj --help-hidden %t | FileCheck --check-prefix=CHECK-READOBJ %s
 # RUN: llvm-tblgen --help-hidden %t | FileCheck --check-prefix=CHECK-TBLGEN %s
 # RUN: llvm-opt-report --help-hidden %t | FileCheck --check-prefix=CHECK-OPT-RPT %s
 # RUN: llvm-dwarfdump --help-hidden %t | FileCheck --check-prefix=CHECK-DWARF %s
 # RUN: llvm-dwarfdump -h %t | FileCheck --check-prefix=CHECK-DWARF-H %s
 
 
 # CHECK-OBJDUMP: -h  - Alias for --section-headers
 # CHECK-READOBJ: -h  - Alias for --file-headers
-# CHECK-TBLGEN:  -h  - Alias for -help
-# CHECK-OPT-RPT: -h  - Alias for -help
+# CHECK-TBLGEN:  -h  - Alias for --help
+# CHECK-OPT-RPT: -h  - Alias for --help
 # CHECK-DWARF:   -h  - Alias for -help
 
 # llvm-dwarfdump declares `-h` option and prints special help in that case,
 # which is weird, but makes for a good test, i.e., shows the default `-h`
 # wasn't used.
-# CHECK-DWARF-H-NOT: -help-list  - Display list of available options (-help-list-hidden for more)
+# CHECK-DWARF-H-NOT: --help-list  - Display list of available options (--help-list-hidden for more)

llvm/trunk/unittests/Support/CommandLineTest.cpp

template <typename... Ts> std::string runTest(Ts... OptionAttributes) {
     {
       OutputRedirector Stdout(fileno(stdout));
       if (!Stdout.Valid)
         return "";
       File.FilePath = Stdout.FilePath;
 
       StackOption<OptionValue> TestOption(Opt, cl::desc(HelpText),
                                           OptionAttributes...);
-      printOptionInfo(TestOption, 25);
+      printOptionInfo(TestOption, 26);
       outs().flush();
     }
     auto Buffer = MemoryBuffer::getFile(File.FilePath);
     if (!Buffer)
       return "";
     return Buffer->get()->getBuffer().str();
   }
 

 };
 
 TEST_F(PrintOptionInfoTest, PrintOptionInfoValueOptionalWithoutSentinel) {
   std::string Output =
       runTest(cl::ValueOptional,
               cl::values(clEnumValN(OptionValue::Val, "v1", "desc1")));
 
   // clang-format off
-  EXPECT_EQ(Output, ("  -" + Opt + "=<value> - " + HelpText + "\n"
-                     "    =v1                -   desc1\n")
+  EXPECT_EQ(Output, ("  --" + Opt + "=<value> - " + HelpText + "\n"
+                     "    =v1                 -   desc1\n")
                         .str());
   // clang-format on
 }
 
 TEST_F(PrintOptionInfoTest, PrintOptionInfoValueOptionalWithSentinel) {
   std::string Output = runTest(
       cl::ValueOptional, cl::values(clEnumValN(OptionValue::Val, "v1", "desc1"),
                                     clEnumValN(OptionValue::Val, "", "")));
 
   // clang-format off
   EXPECT_EQ(Output,
-            ("  -" + Opt + "         - " + HelpText + "\n"
-             "  -" + Opt + "=<value> - " + HelpText + "\n"
-             "    =v1                -   desc1\n")
+            ("  --" + Opt + "         - " + HelpText + "\n"
+             "  --" + Opt + "=<value> - " + HelpText + "\n"
+             "    =v1                 -   desc1\n")
                 .str());
   // clang-format on
 }
 
 TEST_F(PrintOptionInfoTest, PrintOptionInfoValueOptionalWithSentinelWithHelp) {
   std::string Output = runTest(
       cl::ValueOptional, cl::values(clEnumValN(OptionValue::Val, "v1", "desc1"),
                                     clEnumValN(OptionValue::Val, "", "desc2")));
 
   // clang-format off
-  EXPECT_EQ(Output, ("  -" + Opt + "         - " + HelpText + "\n"
-                     "  -" + Opt + "=<value> - " + HelpText + "\n"
-                     "    =v1                -   desc1\n"
-                     "    =<empty>           -   desc2\n")
+  EXPECT_EQ(Output, ("  --" + Opt + "         - " + HelpText + "\n"
+                     "  --" + Opt + "=<value> - " + HelpText + "\n"
+                     "    =v1                 -   desc1\n"
+                     "    =<empty>            -   desc2\n")
                         .str());
   // clang-format on
 }
 
 TEST_F(PrintOptionInfoTest, PrintOptionInfoValueRequiredWithEmptyValueName) {
   std::string Output = runTest(
       cl::ValueRequired, cl::values(clEnumValN(OptionValue::Val, "v1", "desc1"),
                                     clEnumValN(OptionValue::Val, "", "")));
 
   // clang-format off
-  EXPECT_EQ(Output, ("  -" + Opt + "=<value> - " + HelpText + "\n"
-                     "    =v1                -   desc1\n"
+  EXPECT_EQ(Output, ("  --" + Opt + "=<value> - " + HelpText + "\n"
+                     "    =v1                 -   desc1\n"
                      "    =<empty>\n")
                         .str());
   // clang-format on
 }
 
 TEST_F(PrintOptionInfoTest, PrintOptionInfoEmptyValueDescription) {
   std::string Output = runTest(
       cl::ValueRequired, cl::values(clEnumValN(OptionValue::Val, "v1", "")));
 
   // clang-format off
   EXPECT_EQ(Output,
-            ("  -" + Opt + "=<value> - " + HelpText + "\n"
+            ("  --" + Opt + "=<value> - " + HelpText + "\n"
              "    =v1\n").str());
   // clang-format on
 }
 
 class GetOptionWidthTest : public ::testing::Test {
 public:
   enum class OptionValue { Val };
 
   template <typename... Ts>
   size_t runTest(StringRef ArgName, Ts... OptionAttributes) {
     StackOption<OptionValue> TestOption(ArgName, cl::desc("some help"),
                                         OptionAttributes...);
     return getOptionWidth(TestOption);
   }
 
 private:
   // This is a workaround for cl::Option sub-classes having their
   // printOptionInfo
   // functions private.
   size_t getOptionWidth(const cl::Option &O) { return O.getOptionWidth(); }
 };
 
 TEST_F(GetOptionWidthTest, GetOptionWidthArgNameLonger) {
   StringRef ArgName("a-long-argument-name");
-  size_t ExpectedStrSize = ("  -" + ArgName + "=<value> - ").str().size();
+  size_t ExpectedStrSize = ("  --" + ArgName + "=<value> - ").str().size();
   EXPECT_EQ(
       runTest(ArgName, cl::values(clEnumValN(OptionValue::Val, "v", "help"))),
       ExpectedStrSize);
 }
 
 TEST_F(GetOptionWidthTest, GetOptionWidthFirstOptionNameLonger) {
   StringRef OptName("a-long-option-name");
   size_t ExpectedStrSize = ("    =" + OptName + " - ").str().size();