diff --git a/src/stack.rs b/src/stack.rs
index 21e5e83..34907e5 100644
--- a/src/stack.rs
+++ b/src/stack.rs
@@ -4,7 +4,6 @@ use std::ops::Deref;
 use crate::error::*;
 
 pub struct Stack<T, const CAP: usize> {
-    // items: Box<[MaybeUninit<Value<'vm>>; CAP]>,
     items: [MaybeUninit<T>; CAP],
     top: usize,
 }
diff --git a/src/vm/jit.rs b/src/vm/jit.rs
index e173e96..442b09b 100644
--- a/src/vm/jit.rs
+++ b/src/vm/jit.rs
@@ -1,26 +1,77 @@
-use inkwell::OptimizationLevel;
+use std::pin::Pin;
+
+use inkwell::types::{BasicType, BasicTypeEnum, FunctionType, StructType};
+use inkwell::values::{BasicValueEnum, FunctionValue, IntValue};
+use inkwell::{AddressSpace, OptimizationLevel};
 use inkwell::builder::Builder;
 use inkwell::context::Context;
 use inkwell::execution_engine::ExecutionEngine;
 use inkwell::module::Module;
 
+use crate::stack::Stack;
+
+use super::STACK_SIZE;
+
+#[repr(usize)]
+pub enum ValueTag {
+    Int,
+    String,
+    Bool,
+    AttrSet,
+    List,
+    Function,
+    Thunk,
+    Path
+}
+
+#[repr(C)]
+pub struct JITValue {
+    tag: ValueTag,
+    data: u64
+}
+
 pub struct JITContext<'ctx> {
     context: &'ctx Context,
     module: Module<'ctx>,
     builder: Builder<'ctx>,
     execution_engine: ExecutionEngine<'ctx>,
+    stack: Stack<BasicValueEnum<'ctx>, STACK_SIZE>,
+    cur_func: Option<FunctionValue<'ctx>>,
+
+    value_type: StructType<'ctx>,
+    func_type: FunctionType<'ctx>,
 }
 
 impl<'ctx> JITContext<'ctx> {
-    pub fn new(context: &Context) -> JITContext {
+    pub fn new(context: &'ctx Context) -> Pin<Box<Self>> {
         let module = context.create_module("nixjit");
-        JITContext {
+        let stack = Stack::new();
+
+        let int_type = context.i64_type();
+        let pointer_type = context.ptr_type(AddressSpace::default());
+        let value_type = context.struct_type(&[int_type.into(), int_type.into()], false);
+        let func_type = value_type.fn_type(&[pointer_type.into(), pointer_type.into(), value_type.into()], false);
+
+        Pin::new(Box::new(JITContext {
             execution_engine: module
-                .create_jit_execution_engine(OptimizationLevel::None)
+                .create_jit_execution_engine(OptimizationLevel::Default)
                 .unwrap(),
             builder: context.create_builder(),
             context,
             module,
-        }
+            stack,
+            cur_func: None,
+
+            value_type,
+            func_type,
+        }))
+    }
+
+    fn new_int(&self, int: i64) -> IntValue {
+        self.context.i64_type().const_int(int as u64, false)
+    }
+
+    pub fn start_trace(&mut self) {
+        
     }
 }
diff --git a/src/vm/mod.rs b/src/vm/mod.rs
index 07baf0f..d549329 100644
--- a/src/vm/mod.rs
+++ b/src/vm/mod.rs
@@ -1,5 +1,6 @@
 use std::cell::RefCell;
 use std::collections::HashMap;
+use std::pin::Pin;
 use std::rc::Rc;
 
 use crate::builtins::env;
@@ -21,9 +22,9 @@ mod jit;
 #[cfg(test)]
 mod test;
 
-const STACK_SIZE: usize = 8 * 1024 / size_of::<Value>();
+pub const STACK_SIZE: usize = 8 * 1024 / size_of::<Value>();
 
-pub fn run(prog: Program, jit: JITContext<'_>) -> Result<p::Value> {
+pub fn run(prog: Program, jit: Pin<Box<JITContext<'_>>>) -> Result<p::Value> {
     let vm = VM::new(
         prog.thunks,
         prog.funcs,
@@ -45,7 +46,7 @@ pub struct VM<'jit> {
     symbols: RefCell<Vec<EcoString>>,
     symmap: RefCell<HashMap<EcoString, usize>>,
     consts: Box<[Const]>,
-    jit: JITContext<'jit>,
+    jit: Pin<Box<JITContext<'jit>>>
 }
 
 impl<'vm, 'jit: 'vm> VM<'jit> {