add version information for the compiler (#1705)

src/cmdline.rs

@@ -75,6 +75,10 @@ pub struct Opts {
     #[argh(switch, long = "dump-ir")]
     /// print out the IR after every pass
     pub dump_ir: bool,
+
+    #[argh(switch, long = "version")]
+    /// print out the version information
+    pub version: bool,
 }
 
 fn read_path(path: &str) -> Result<PathBuf, String> {

src/driver.rs

@@ -11,6 +11,16 @@ pub fn run_compiler() -> CalyxResult<()> {
     // parse the command line arguments into Opts struct
     let mut opts = Opts::get_opts()?;
 
+    // Return the version and the git commit this was built on
+    if opts.version {
+        println!("Calyx compiler version {}", env!("CARGO_PKG_VERSION"));
+        println!(
+            "Library location: {}",
+            option_env!("CALYX_PRIMITIVES_DIR").unwrap_or(".")
+        );
+        return Ok(());
+    }
+
     // enable tracing
     env_logger::Builder::new()
         .format_timestamp(None)