Enhance the --help message of composite target (#13842)

Presently --help for vitis displays the target and option string,
it has no description.  Eg:  target vitis-ai dpu<class 'str'>

This can be made more meaningful by fetching the description from
the config node of the target.  Eg: Vitis AI DPU identifier

Signed-off-by: MNGanesan <[email protected]>

Author: MNGanesan

python/tvm/driver/tvmc/target.py

@@ -72,7 +72,7 @@ def _generate_codegen_args(parser, codegen_name):
                     target_group.add_argument(
                         f"--target-{codegen_name}-{target_option}",
                         type=python_type,
-                        help=f"target {codegen_name} {target_option}{python_type}",
+                        help=field.description,
                     )
 
 

tests/python/driver/tvmc/test_target_options.py

@@ -60,6 +60,29 @@ def test_mapping_target_args():
     assert reconstruct_target_args(parsed) == {"llvm": {"mcpu": "cortex-m3"}}
 
 
+@tvm.testing.requires_vitis_ai
+def test_composite_target_cmd_line_help():
+    parser = argparse.ArgumentParser()
+    generate_target_args(parser)
+    assert parser._option_string_actions["--target-vitis-ai-dpu"].help == "Vitis AI DPU identifier"
+    assert (
+        parser._option_string_actions["--target-vitis-ai-build_dir"].help
+        == "Build directory to be used (optional, debug)"
+    )
+    assert (
+        parser._option_string_actions["--target-vitis-ai-work_dir"].help
+        == "Work directory to be used (optional, debug)"
+    )
+    assert (
+        parser._option_string_actions["--target-vitis-ai-export_runtime_module"].help
+        == "Export the Vitis AI runtime module to this file"
+    )
+    assert (
+        parser._option_string_actions["--target-vitis-ai-load_runtime_module"].help
+        == "Load the Vitis AI runtime module to this file"
+    )
+
+
 @tvm.testing.requires_cmsisnn
 def test_include_known_codegen():
     parser = argparse.ArgumentParser()