add help text, w/ tests

1 files changed, 9 insertions, 1 deletions

diff --git a/src/wasm-option-parser.c b/src/wasm-option-parser.c
index b5cd280b..4d9eeabd 100644
--- a/src/wasm-option-parser.c
+++ b/src/wasm-option-parser.c
@@ -160,10 +160,18 @@ void wasm_parse_options(WasmOptionParser* parser,
   }
 }
 
+static const char* trim_argv0(const char* argv0) {
+  char* last_slash = strrchr(argv0, '/');
+  if (last_slash)
+    return last_slash + 1;
+  return argv0;
+}
+
 void wasm_print_help(WasmOptionParser* parser) {
   int i;
   /* TODO(binji): do something more generic for filename here */
-  printf("usage: %s [options] filename\n", parser->argv0);
+  printf("usage: %s [options] filename\n\n", trim_argv0(parser->argv0));
+  printf("%s\n", parser->description);
   printf("options:\n");
 
   const int extra_space = 8;