2 files changed, 77 insertions, 0 deletions
diff --git a/src/tools/miropt-test-tools/Cargo.toml b/src/tools/miropt-test-tools/Cargo.toml
new file mode 100644
index 000000000..8589a44cf
--- /dev/null
+++ b/src/tools/miropt-test-tools/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "miropt-test-tools"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+regex = "1.0"
diff --git a/src/tools/miropt-test-tools/src/lib.rs b/src/tools/miropt-test-tools/src/lib.rs
new file mode 100644
index 000000000..cfba7d583
--- /dev/null
+++ b/src/tools/miropt-test-tools/src/lib.rs
@@ -0,0 +1,70 @@
+use std::fs;
+
+pub struct MiroptTestFiles {
+    pub expected_file: std::path::PathBuf,
+    pub from_file: String,
+    pub to_file: Option<String>,
+}
+
+pub fn files_for_miropt_test(testfile: &std::path::Path, bit_width: u32) -> Vec<MiroptTestFiles> {
+    let mut out = Vec::new();
+    let test_file_contents = fs::read_to_string(&testfile).unwrap();
+
+    let test_dir = testfile.parent().unwrap();
+    let test_crate = testfile.file_stem().unwrap().to_str().unwrap().replace('-', "_");
+
+    let bit_width = if test_file_contents.lines().any(|l| l == "// EMIT_MIR_FOR_EACH_BIT_WIDTH") {
+        format!(".{}bit", bit_width)
+    } else {
+        String::new()
+    };
+
+    for l in test_file_contents.lines() {
+        if l.starts_with("// EMIT_MIR ") {
+            let test_name = l.trim_start_matches("// EMIT_MIR ").trim();
+            let mut test_names = test_name.split(' ');
+            // sometimes we specify two files so that we get a diff between the two files
+            let test_name = test_names.next().unwrap();
+            let mut expected_file;
+            let from_file;
+            let to_file;
+
+            if test_name.ends_with(".diff") {
+                let trimmed = test_name.trim_end_matches(".diff");
+                let test_against = format!("{}.after.mir", trimmed);
+                from_file = format!("{}.before.mir", trimmed);
+                expected_file = format!("{}{}.diff", trimmed, bit_width);
+                assert!(test_names.next().is_none(), "two mir pass names specified for MIR diff");
+                to_file = Some(test_against);
+            } else if let Some(first_pass) = test_names.next() {
+                let second_pass = test_names.next().unwrap();
+                assert!(test_names.next().is_none(), "three mir pass names specified for MIR diff");
+                expected_file =
+                    format!("{}{}.{}-{}.diff", test_name, bit_width, first_pass, second_pass);
+                let second_file = format!("{}.{}.mir", test_name, second_pass);
+                from_file = format!("{}.{}.mir", test_name, first_pass);
+                to_file = Some(second_file);
+            } else {
+                let ext_re = regex::Regex::new(r#"(\.(mir|dot|html))$"#).unwrap();
+                let cap = ext_re
+                    .captures_iter(test_name)
+                    .next()
+                    .expect("test_name has an invalid extension");
+                let extension = cap.get(1).unwrap().as_str();
+                expected_file =
+                    format!("{}{}{}", test_name.trim_end_matches(extension), bit_width, extension,);
+                from_file = test_name.to_string();
+                assert!(test_names.next().is_none(), "two mir pass names specified for MIR dump");
+                to_file = None;
+            };
+            if !expected_file.starts_with(&test_crate) {
+                expected_file = format!("{}.{}", test_crate, expected_file);
+            }
+            let expected_file = test_dir.join(expected_file);
+
+            out.push(MiroptTestFiles { expected_file, from_file, to_file });
+        }
+    }
+
+    out
+}