diff --git a/Cargo.lock b/Cargo.lock
index f53b5bf..97aba67 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -521,6 +521,7 @@ dependencies = [
  "inkwell",
  "insta",
  "itertools",
+ "lazy_static",
  "nac3parser",
  "parking_lot 0.11.2",
  "rayon",
diff --git a/nac3core/Cargo.toml b/nac3core/Cargo.toml
index ec4cd3c..12a7248 100644
--- a/nac3core/Cargo.toml
+++ b/nac3core/Cargo.toml
@@ -10,6 +10,7 @@ crossbeam = "0.8.1"
 parking_lot = "0.11.1"
 rayon = "1.5.1"
 nac3parser = { path = "../nac3parser" }
+lazy_static = "1.4.0"
 
 [dependencies.inkwell]
 git = "https://github.com/TheDan64/inkwell.git"
diff --git a/nac3core/src/codegen/mod.rs b/nac3core/src/codegen/mod.rs
index 6959651..a7be388 100644
--- a/nac3core/src/codegen/mod.rs
+++ b/nac3core/src/codegen/mod.rs
@@ -31,6 +31,7 @@ use std::sync::{
     Arc,
 };
 use std::thread;
+use lazy_static::lazy_static;
 
 pub mod concrete_type;
 pub mod expr;
@@ -52,6 +53,12 @@ pub struct StaticValueStore {
 
 pub type VarValue<'ctx> = (PointerValue<'ctx>, Option<Arc<dyn StaticValue + Send + Sync>>, i64);
 
+lazy_static!(
+    // HACK: The Mutex is a work-around for issue
+    // https://git.m-labs.hk/M-Labs/nac3/issues/275
+    static ref PASSES_INIT_LOCK: Mutex<AtomicBool> = Mutex::new(AtomicBool::new(true));
+);
+
 pub struct CodeGenContext<'ctx, 'a> {
     pub ctx: &'ctx Context,
     pub builder: Builder<'ctx>,
@@ -218,10 +225,16 @@ impl WorkerRegistry {
             context.i32_type().const_int(4, false),
         );
 
-        let pass_builder = PassManagerBuilder::create();
-        pass_builder.set_optimization_level(OptimizationLevel::Default);
         let passes = PassManager::create(&module);
-        pass_builder.populate_function_pass_manager(&passes);
+
+        // HACK: This critical section is a work-around for issue
+        // https://git.m-labs.hk/M-Labs/nac3/issues/275
+        {
+            let _data = PASSES_INIT_LOCK.lock();
+            let pass_builder = PassManagerBuilder::create();
+            pass_builder.set_optimization_level(OptimizationLevel::Default);
+            pass_builder.populate_function_pass_manager(&passes);
+        }
 
         let mut errors = HashSet::new();
         while let Some(task) = self.receiver.recv().unwrap() {