message: Add CLI option for optimized backends.
diff: @@ -119,6 +119,15 @@ struct Run {
  #[structopt(long = "resume")]
  resume: Option<String>,
  + /// Optimized backends for higher tiers.
  + #[cfg(feature = "managed")]
  + #[structopt(
  + long = "optimized-backends",
  + multiple = true,
  + raw(possible_values = "Backend::variants()", case_insensitive = "true")
  + )]
  + optimized_backends: Vec<Backend>,
  +
  /// Whether or not state tracking should be disabled during compilation.
  /// State tracking is necessary for tier switching and backtracing.
  #[structopt(long = "no-track-state")]
  @@ -525,9 +534,9 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
  &import_object,
  start_raw,
  &mut instance,
  - vec![
  - Box::new(|| get_compiler_by_backend(Backend::LLVM).unwrap()),
  - ],
  + options.optimized_backends.iter().map(|&backend| -> Box<dyn Fn() -> Box<dyn Compiler> + Send> {
  + Box::new(move || get_compiler_by_backend(backend).unwrap())
  + }).collect(),
  interactive_shell,
  )?;
  