Add test run to cranelift-filetests to allow executing CLIF (#890)

* Add ability to run CLIF IR using `clif-util run [-v] {file}` and add `test run` to cranelift-filetests to allow executing CLIF

This re-factors the compile/execute parts to a FunctionRunner that is shared between cranelift-filetests and clif-util. CLIF can be now be run using `clif-util run` as well as during `clif-util test` for files with a `test run` header. As before, only functions suffixed with a `run` comment are executed. The `run: fn(...) == ...` expression syntax is left for a subsequent change.

cranelift/src/clif-util.rs

@@ -33,6 +33,7 @@ mod cat;
 mod compile;
 mod disasm;
 mod print_cfg;
+mod run;
 mod utils;
 
 /// A command either succeeds or fails with an error message.
@@ -162,6 +163,13 @@ fn main() {
                 .arg(add_input_file_arg())
                 .arg(add_debug_flag()),
         )
+        .subcommand(
+            SubCommand::with_name("run")
+                .about("Execute CLIF code and verify with test expressions")
+                .arg(add_verbose_flag())
+                .arg(add_input_file_arg())
+                .arg(add_debug_flag()),
+        )
         .subcommand(
             SubCommand::with_name("cat")
                 .about("Outputs .clif file")
@@ -224,6 +232,14 @@ fn main() {
             )
             .map(|_time| ())
         }
+        ("run", Some(rest_cmd)) => {
+            handle_debug_flag(rest_cmd.is_present("debug"));
+            run::run(
+                get_vec(rest_cmd.values_of("file")),
+                rest_cmd.is_present("verbose"),
+            )
+            .map(|_time| ())
+        }
         ("pass", Some(rest_cmd)) => {
             handle_debug_flag(rest_cmd.is_present("debug"));