1 files changed, 55 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_cranelift/build_system/config.rs b/compiler/rustc_codegen_cranelift/build_system/config.rs
new file mode 100644
index 000000000..ef540cf1f
--- /dev/null
+++ b/compiler/rustc_codegen_cranelift/build_system/config.rs
@@ -0,0 +1,55 @@
+use std::{fs, process};
+
+fn load_config_file() -> Vec<(String, Option<String>)> {
+    fs::read_to_string("config.txt")
+        .unwrap()
+        .lines()
+        .map(|line| if let Some((line, _comment)) = line.split_once('#') { line } else { line })
+        .map(|line| line.trim())
+        .filter(|line| !line.is_empty())
+        .map(|line| {
+            if let Some((key, val)) = line.split_once('=') {
+                (key.trim().to_owned(), Some(val.trim().to_owned()))
+            } else {
+                (line.to_owned(), None)
+            }
+        })
+        .collect()
+}
+
+pub(crate) fn get_bool(name: &str) -> bool {
+    let values = load_config_file()
+        .into_iter()
+        .filter(|(key, _)| key == name)
+        .map(|(_, val)| val)
+        .collect::<Vec<_>>();
+    if values.is_empty() {
+        false
+    } else {
+        if values.iter().any(|val| val.is_some()) {
+            eprintln!("Boolean config `{}` has a value", name);
+            process::exit(1);
+        }
+        true
+    }
+}
+
+pub(crate) fn get_value(name: &str) -> Option<String> {
+    let values = load_config_file()
+        .into_iter()
+        .filter(|(key, _)| key == name)
+        .map(|(_, val)| val)
+        .collect::<Vec<_>>();
+    if values.is_empty() {
+        None
+    } else if values.len() == 1 {
+        if values[0].is_none() {
+            eprintln!("Config `{}` missing value", name);
+            process::exit(1);
+        }
+        values.into_iter().next().unwrap()
+    } else {
+        eprintln!("Config `{}` given multiple values: {:?}", name, values);
+        process::exit(1);
+    }
+}