[CommandLine] Add subcommand groups (#75678)

The patch introduces a `SubCommandGroup` class which represents a list
of subcommands. An option can be added to all these subcommands using
one `cl::sub(group)` command. This simplifies the declaration of options
that are shared across multiple subcommands of a tool.

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/unittests/Support/CommandLineTest.cpp b/llvm/unittests/Support/CommandLineTest.cpp
index ae80490..328674a 100644
--- a/llvm/unittests/Support/CommandLineTest.cpp
+++ b/llvm/unittests/Support/CommandLineTest.cpp
@@ -2274,4 +2274,31 @@ TEST(CommandLineTest, UnknownCommands) {
   EXPECT_EQ(Errs, "prog: Unknown subcommand 'faz'.  Try: 'prog --help'\n");
 }
 
+TEST(CommandLineTest, SubCommandGroups) {
+  // Check that options in subcommand groups are associated with expected
+  // subcommands.
+
+  cl::ResetCommandLineParser();
+
+  StackSubCommand SC1("sc1", "SC1 subcommand");
+  StackSubCommand SC2("sc2", "SC2 subcommand");
+  StackSubCommand SC3("sc3", "SC3 subcommand");
+  cl::SubCommandGroup Group12 = {&SC1, &SC2};
+
+  StackOption<bool> Opt12("opt12", cl::sub(Group12), cl::init(false));
+  StackOption<bool> Opt3("opt3", cl::sub(SC3), cl::init(false));
+
+  // The "--opt12" option is expected to be added to both subcommands in the
+  // group, but not to the top-level "no subcommand" pseudo-subcommand or the
+  // "sc3" subcommand.
+  EXPECT_EQ(1, SC1.OptionsMap.size());
+  EXPECT_TRUE(SC1.OptionsMap.contains("opt12"));
+
+  EXPECT_EQ(1, SC2.OptionsMap.size());
+  EXPECT_TRUE(SC2.OptionsMap.contains("opt12"));
+
+  EXPECT_FALSE(cl::SubCommand::getTopLevel().OptionsMap.contains("opt12"));
+  EXPECT_FALSE(SC3.OptionsMap.contains("opt12"));
+}
+
 } // anonymous namespace