clif-util: add the `souper-to-peepmatic` subcommand (#2200)

This adds a subcommand to the `clif-util` CLI for exposing the Souper->Peepmatic
translation machinery that was introduced in #2192.

cranelift/src/clif-util.rs

@@ -29,6 +29,9 @@ mod print_cfg;
 mod run;
 mod utils;
 
+#[cfg(feature = "peepmatic-souper")]
+mod souper_to_peepmatic;
+
 #[cfg(feature = "wasm")]
 mod wasm;
 
@@ -50,6 +53,15 @@ fn add_single_input_file_arg<'a>() -> clap::Arg<'a, 'a> {
         .help("Specify a file to be used. Use '-' for stdin.")
 }
 
+fn add_output_arg<'a>() -> clap::Arg<'a, 'a> {
+    Arg::with_name("output")
+        .required(true)
+        .default_value("-")
+        .value_name("output")
+        .short("o")
+        .help("Specify output file to be used. Use '-' for stdout.")
+}
+
 fn add_pass_arg<'a>() -> clap::Arg<'a, 'a> {
     Arg::with_name("pass")
         .required(true)
@@ -247,6 +259,12 @@ fn main() {
                 .arg(add_set_flag())
                 .arg(add_target_flag())
                 .arg(add_verbose_flag()),
+        )
+        .subcommand(
+            SubCommand::with_name("souper-to-peepmatic")
+                .about("Convert Souper optimizations into Peepmatic DSL.")
+                .arg(add_single_input_file_arg())
+                .arg(add_output_arg()),
         );
 
     let res_util = match app_cmds.get_matches().subcommand() {
@@ -362,6 +380,24 @@ fn main() {
                 rest_cmd.is_present("verbose"),
             )
         }
+        ("souper-to-peepmatic", Some(rest_cmd)) => {
+            #[cfg(feature = "peepmatic-souper")]
+            {
+                use std::path::Path;
+                souper_to_peepmatic::run(
+                    Path::new(rest_cmd.value_of("single-file").unwrap()),
+                    Path::new(rest_cmd.value_of("output").unwrap()),
+                )
+            }
+            #[cfg(not(feature = "peepmatic-souper"))]
+            {
+                Err(
+                    "Error: clif-util was compiled without suport for the `souper-to-peepmatic` \
+                     subcommand"
+                        .into(),
+                )
+            }
+        }
         _ => Err("Invalid subcommand.".to_owned()),
     };
 

cranelift/src/souper_to_peepmatic.rs

@@ -0,0 +1,32 @@
+use std::io::{Read, Write};
+use std::path::Path;
+
+pub fn run(input: &Path, output: &Path) -> Result<(), String> {
+    let peepmatic_dsl = if input == Path::new("-") {
+        let stdin = std::io::stdin();
+        let mut stdin = stdin.lock();
+        let mut souper_dsl = vec![];
+        stdin
+            .read_to_end(&mut souper_dsl)
+            .map_err(|e| format!("failed to read from stdin: {}", e))?;
+        let souper_dsl =
+            String::from_utf8(souper_dsl).map_err(|e| format!("stdin is not UTF-8: {}", e))?;
+        peepmatic_souper::convert_str(&souper_dsl, Some(Path::new("stdin")))
+            .map_err(|e| e.to_string())?
+    } else {
+        peepmatic_souper::convert_file(input).map_err(|e| e.to_string())?
+    };
+
+    if output == Path::new("-") {
+        let stdout = std::io::stdout();
+        let mut stdout = stdout.lock();
+        stdout
+            .write_all(peepmatic_dsl.as_bytes())
+            .map_err(|e| format!("error writing to stdout: {}", e))?;
+    } else {
+        std::fs::write(output, peepmatic_dsl.as_bytes())
+            .map_err(|e| format!("error writing to {}: {}", output.display(), e))?;
+    }
+
+    Ok(())
+}