Remove TopLevelCommand abstraction completely.

Author: Prabhuk

llvm/examples/OptSubcommand/llvm-hello-sub.cpp

@@ -82,6 +82,7 @@ int main(int argc, char **argv) {
       T.getCommands(), HandleMultipleSubcommands, HandleOtherPositionals);
   // Handle help. When help options is found, ignore all other options and exit
   // after printing help.
+
   if (Args.hasArg(OPT_help)) {
     T.printHelp(llvm::outs(), "llvm-hello-sub [subcommand] [options]",
                 "LLVM Hello Subcommand Example", false, false, Visibility(),

llvm/include/llvm/Option/OptParser.td

@@ -108,13 +108,8 @@ class Subcommand<string name, string helpText, string usage = "">
   string Usage = usage;
 }
 
-// Compile time representation for top level command (aka toolname).
-// Offers backward compatibility with existing Option class definitions before
-// introduction of commandGroup in Option class to support subcommands.
-def TopLevelCommand : Command<"TopLevelCommand">;
-
 class Option<list<string> prefixes, string name, OptionKind kind,
-             list<Command> commandGroup = [TopLevelCommand]> {
+             list<Command> commandGroup = []> {
   string EnumName = ?; // Uses the def name if undefined.
   list<string> Prefixes = prefixes;
   string Name = name;
@@ -150,28 +145,27 @@ class Option<list<string> prefixes, string name, OptionKind kind,
 
 // Helpers for defining options.
 
-class Flag<list<string> prefixes, string name,
-           list<Command> commandGroup = [TopLevelCommand]>
+class Flag<list<string> prefixes, string name, list<Command> commandGroup = []>
     : Option<prefixes, name, KIND_FLAG, commandGroup>;
 class Joined<list<string> prefixes, string name,
-             list<Command> commandGroup = [TopLevelCommand]>
+             list<Command> commandGroup = []>
     : Option<prefixes, name, KIND_JOINED, commandGroup>;
 class Separate<list<string> prefixes, string name,
-               list<Command> commandGroup = [TopLevelCommand]>
+               list<Command> commandGroup = []>
     : Option<prefixes, name, KIND_SEPARATE, commandGroup>;
 class CommaJoined<list<string> prefixes, string name,
-                  list<Command> commandGroup = [TopLevelCommand]>
+                  list<Command> commandGroup = []>
     : Option<prefixes, name, KIND_COMMAJOINED, commandGroup>;
 class MultiArg<list<string> prefixes, string name, int numargs,
-               list<Command> commandGroup = [TopLevelCommand]>
+               list<Command> commandGroup = []>
     : Option<prefixes, name, KIND_MULTIARG, commandGroup> {
   int NumArgs = numargs;
 }
 class JoinedOrSeparate<list<string> prefixes, string name,
-                       list<Command> commandGroup = [TopLevelCommand]>
+                       list<Command> commandGroup = []>
     : Option<prefixes, name, KIND_JOINED_OR_SEPARATE, commandGroup>;
 class JoinedAndSeparate<list<string> prefixes, string name,
-                        list<Command> commandGroup = [TopLevelCommand]>
+                        list<Command> commandGroup = []>
     : Option<prefixes, name, KIND_JOINED_AND_SEPARATE, commandGroup>;
 
 // Mix-ins for adding optional attributes.
@@ -295,7 +289,7 @@ class ValueExtractor<code extractor> { code ValueExtractor = extractor; }
 
 // FIXME: Have generator validate that these appear in correct position (and
 // aren't duplicated).
-def INPUT : Option<[], "<input>", KIND_INPUT, [TopLevelCommand]>;
-def UNKNOWN : Option<[], "<unknown>", KIND_UNKNOWN, [TopLevelCommand]>;
+def INPUT : Option<[], "<input>", KIND_INPUT>;
+def UNKNOWN : Option<[], "<unknown>", KIND_UNKNOWN>;
 
 #endif // LLVM_OPTION_OPTPARSER_TD

llvm/lib/Option/ArgList.cpp

@@ -218,8 +218,8 @@ StringRef ArgList::getSubcommand(
 
     size_t OldSize = SubCommands.size();
     for (const OptTable::Command &CMD : Commands) {
-      if (StringRef(CMD.Name) == opt::TopLevelCommandName)
-        continue;
+      // if (StringRef(CMD.Name) == opt::TopLevelCommandName)
+      //   continue;
       if (StringRef(CMD.Name) == A->getValue())
         SubCommands.push_back(A->getValue());
     }

llvm/lib/Option/OptTable.cpp

@@ -789,52 +789,62 @@ void OptTable::internalPrintHelp(
   std::map<std::string, std::vector<OptionInfo>> GroupedOptionHelp;
 
   const Command *ActiveCommand = getActiveCommand(Commands, Subcommand);
-  if (ActiveCommand) {
+  if (!Subcommand.empty()) {
+    assert(ActiveCommand != nullptr && "Not a valid registered subcommand.");
     OS << ActiveCommand->HelpText << "\n\n";
     if (!StringRef(ActiveCommand->Usage).empty())
       OS << "USAGE: " << ActiveCommand->Usage << "\n\n";
   } else {
     OS << "USAGE: " << Usage << "\n\n";
     if (Commands.size() > 1) {
       OS << "SUBCOMMANDS:\n\n";
-      // This loop prints subcommands list and sets ActiveCommand to
-      // TopLevelCommand while iterating over all commands.
-      for (const auto &C : Commands) {
-        if (StringRef(C.Name) == opt::TopLevelCommandName) {
-          ActiveCommand = &C;
-          continue;
-        }
+      for (const auto &C : Commands)
         OS << C.Name << " - " << C.HelpText << "\n";
-      }
       OS << "\n";
     }
   }
 
-  auto DoesOptionBelongToActiveCommand =
-      [this, &ActiveCommand](const Info &CandidateInfo) {
-        // ActiveCommand won't be set for tools that did not create command
-        // group info table.
-        if (!ActiveCommand)
-          return true;
-        ArrayRef<unsigned> CommandIDs =
-            CandidateInfo.getCommandIDs(CommandIDsTable);
-        unsigned ActiveCommandID = ActiveCommand - Commands.data();
-        return is_contained(CommandIDs, ActiveCommandID);
-      };
+  auto DoesOptionBelongToSubcommand = [&](const Info &CandidateInfo) {
+    // llvm::outs() << CandidateInfo.
+    ArrayRef<unsigned> CommandIDs =
+        CandidateInfo.getCommandIDs(CommandIDsTable);
+
+    // Options with no commands are global.
+    if (CommandIDs.empty()) {
+      // if Subcommand is not empty then don't print global options.
+      return Subcommand.empty();
+    }
+
+    // If we are not in a subcommand, don't show subcommand-specific options.
+    if (Subcommand.empty())
+      return false;
+
+    // The command ID is its index in the Commands table.
+    unsigned ActiveCommandID = ActiveCommand - &Commands[0];
+
+    // Check if the option belongs to the active subcommand.
+    for (unsigned ID : CommandIDs) {
+      if (ID == ActiveCommandID) {
+        return true;
+      }
+    }
+    return false;
+  };
 
   for (unsigned Id = 1, e = getNumOptions() + 1; Id != e; ++Id) {
     // FIXME: Split out option groups.
     if (getOptionKind(Id) == Option::GroupClass)
       continue;
 
     const Info &CandidateInfo = getInfo(Id);
+
     if (!ShowHidden && (CandidateInfo.Flags & opt::HelpHidden))
       continue;
 
     if (ExcludeOption(CandidateInfo))
       continue;
 
-    if (!DoesOptionBelongToActiveCommand(CandidateInfo))
+    if (!DoesOptionBelongToSubcommand(CandidateInfo))
       continue;
 
     // If an alias doesn't have a help text, show a help text for the aliased

llvm/utils/TableGen/OptionParserEmitter.cpp

@@ -262,10 +262,11 @@ static void emitOptionParser(const RecordKeeper &Records, raw_ostream &OS) {
 
   std::vector<const Record *> Commands =
       Records.getAllDerivedDefinitions("Command");
-  // TopLevelCommand should come first.
-  std::stable_partition(Commands.begin(), Commands.end(), [](const Record *R) {
-    return R->getName() == opt::TopLevelCommandName;
-  });
+  // // TopLevelCommand should come first.
+  // std::stable_partition(Commands.begin(), Commands.end(), [](const Record *R)
+  // {
+  //   return R->getName() == opt::TopLevelCommandName;
+  // });
 
   emitSourceFileHeader("Option Parsing Definitions", OS);