3 files changed, 174 insertions, 0 deletions
diff --git a/llvm/examples/OptSubcommand/CMakeLists.txt b/llvm/examples/OptSubcommand/CMakeLists.txt
new file mode 100644
index 0000000..debc948
--- /dev/null
+++ b/llvm/examples/OptSubcommand/CMakeLists.txt
@@ -0,0 +1,19 @@
+# Set the .td file to be processed for this target.
+set(LLVM_TARGET_DEFINITIONS Opts.td)
+
+tablegen(LLVM Opts.inc -gen-opt-parser-defs)
+add_public_tablegen_target(HelloSubTableGen)
+
+set(LLVM_LINK_COMPONENTS  
+  Support
+  Option  
+  )
+
+add_llvm_example(OptSubcommand
+  llvm-hello-sub.cpp  
+  )
+
+target_include_directories(OptSubcommand
+  PRIVATE
+  ${CMAKE_CURRENT_BINARY_DIR}
+  )
diff --git a/llvm/examples/OptSubcommand/Opts.td b/llvm/examples/OptSubcommand/Opts.td
new file mode 100644
index 0000000..7c980ee
--- /dev/null
+++ b/llvm/examples/OptSubcommand/Opts.td
@@ -0,0 +1,18 @@
+include "llvm/Option/OptParser.td"
+
+def sc_foo : SubCommand<"foo", "HelpText for SubCommand foo.">;
+
+def sc_bar : SubCommand<"bar", "HelpText for SubCommand bar.",
+                        "OptSubcommand bar <options>">;
+
+def help : Flag<["--"], "help">,
+           HelpText<"OptSubcommand <subcommand> <options>">;
+
+def version : Flag<["-"], "version">,
+              HelpText<"Toplevel Display the version number">;
+
+def uppercase : Flag<["-"], "uppercase", [sc_foo, sc_bar]>,
+                HelpText<"Print in uppercase">;
+
+def lowercase : Flag<["-"], "lowercase", [sc_foo]>,
+                HelpText<"Print in lowercase">;
diff --git a/llvm/examples/OptSubcommand/llvm-hello-sub.cpp b/llvm/examples/OptSubcommand/llvm-hello-sub.cpp
new file mode 100644
index 0000000..8071f56
--- /dev/null
+++ b/llvm/examples/OptSubcommand/llvm-hello-sub.cpp
@@ -0,0 +1,137 @@
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Option/OptTable.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+using namespace llvm::opt;
+
+namespace {
+enum ID {
+  OPT_INVALID = 0,
+#define OPTION(PREFIXES, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS,       \
+               VISIBILITY, PARAM, HELPTEXT, HELPTEXTSFORVARIANTS, METAVAR,     \
+               VALUES, SUBCOMMANDIDS_OFFSET)                                   \
+  OPT_##ID,
+#include "Opts.inc"
+#undef OPTION
+};
+#define OPTTABLE_STR_TABLE_CODE
+#include "Opts.inc"
+#undef OPTTABLE_STR_TABLE_CODE
+
+#define OPTTABLE_PREFIXES_TABLE_CODE
+#include "Opts.inc"
+#undef OPTTABLE_PREFIXES_TABLE_CODE
+
+#define OPTTABLE_SUBCOMMAND_IDS_TABLE_CODE
+#include "Opts.inc"
+#undef OPTTABLE_SUBCOMMAND_IDS_TABLE_CODE
+
+#define OPTTABLE_SUBCOMMANDS_CODE
+#include "Opts.inc"
+#undef OPTTABLE_SUBCOMMANDS_CODE
+
+static constexpr OptTable::Info InfoTable[] = {
+#define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
+#include "Opts.inc"
+#undef OPTION
+};
+
+class HelloSubOptTable : public GenericOptTable {
+public:
+  HelloSubOptTable()
+      : GenericOptTable(OptionStrTable, OptionPrefixesTable, InfoTable,
+                        /*IgnoreCase=*/false, OptionSubCommands,
+                        OptionSubCommandIDsTable) {}
+};
+} // namespace
+
+int main(int argc, char **argv) {
+  InitLLVM X(argc, argv);
+  HelloSubOptTable T;
+  unsigned MissingArgIndex, MissingArgCount;
+
+  auto HandleMultipleSubcommands = [](ArrayRef<StringRef> SubCommands) {
+    assert(SubCommands.size() > 1);
+    llvm::errs() << "error: more than one subcommand passed [\n";
+    for (auto SC : SubCommands)
+      llvm::errs() << " `" << SC << "`\n";
+    llvm::errs() << "]\n";
+    llvm::errs() << "See --help.\n";
+    exit(1);
+  };
+
+  auto HandleOtherPositionals = [](ArrayRef<StringRef> Positionals) {
+    assert(!Positionals.empty());
+    llvm::errs() << "error: unknown positional argument(s) [\n";
+    for (auto SC : Positionals)
+      llvm::errs() << " `" << SC << "`\n";
+    llvm::errs() << "]\n";
+    llvm::errs() << "See --help.\n";
+    exit(1);
+  };
+
+  InputArgList Args = T.ParseArgs(ArrayRef(argv + 1, argc - 1), MissingArgIndex,
+                                  MissingArgCount);
+
+  StringRef SubCommand = Args.getSubCommand(
+      T.getSubCommands(), 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(),
+                SubCommand);
+    return 0;
+  }
+
+  auto HandleSubCommandArg = [&](ID OptionType) {
+    if (!Args.hasArg(OptionType))
+      return false;
+    auto O = T.getOption(OptionType);
+    if (!O.isRegisteredSC(SubCommand)) {
+      llvm::errs() << "Option [" << O.getName()
+                   << "] is not valid for SubCommand [" << SubCommand << "]\n";
+      return false;
+    }
+    return true;
+  };
+
+  bool HasUnknownOptions = false;
+  for (const Arg *A : Args.filtered(OPT_UNKNOWN)) {
+    HasUnknownOptions = true;
+    llvm::errs() << "Unknown option `" << A->getAsString(Args) << "'\n";
+  }
+  if (HasUnknownOptions) {
+    llvm::errs() << "See `OptSubcommand --help`.\n";
+    return 1;
+  }
+  if (SubCommand.empty()) {
+    if (Args.hasArg(OPT_version))
+      llvm::outs() << "LLVM Hello SubCommand Example 1.0\n";
+  } else if (SubCommand == "foo") {
+    if (HandleSubCommandArg(OPT_uppercase))
+      llvm::outs() << "FOO\n";
+    else if (HandleSubCommandArg(OPT_lowercase))
+      llvm::outs() << "foo\n";
+
+    if (HandleSubCommandArg(OPT_version))
+      llvm::outs() << "LLVM Hello SubCommand foo Example 1.0\n";
+
+  } else if (SubCommand == "bar") {
+    if (HandleSubCommandArg(OPT_lowercase))
+      llvm::outs() << "bar\n";
+    else if (HandleSubCommandArg(OPT_uppercase))
+      llvm::outs() << "BAR\n";
+
+    if (HandleSubCommandArg(OPT_version))
+      llvm::outs() << "LLVM Hello SubCommand bar Example 1.0\n";
+  }
+
+  return 0;
+}