diff --git a/src/backend/binaryen.rs b/src/backend/binaryen.rs
index cb8a438..9ebe451 100644
--- a/src/backend/binaryen.rs
+++ b/src/backend/binaryen.rs
@@ -43,6 +43,14 @@ impl Module {
         Ok(slice.to_vec())
     }
 
+    pub fn new() -> Result<Module> {
+        let ptr = unsafe { BinaryenModuleCreate() };
+        if ptr.is_null() {
+            bail!("Failed to allocate module");
+        }
+        Ok(Module(ptr))
+    }
+
     pub fn num_funcs(&self) -> usize {
         unsafe { BinaryenGetNumFunctions(self.0) as usize }
     }
@@ -88,6 +96,178 @@ impl Module {
     pub fn module(&self) -> BinaryenModule {
         self.0
     }
+
+    pub fn add_global(&self, ty: ir::Type, mutable: bool, value: Option<u64>) -> ir::Global {
+        let b_ty = Type::from(ty).to_binaryen();
+        let value = value.unwrap_or(0);
+        let init = match ty {
+            ir::Type::I32 => Expression::const_i32(self, value as i32),
+            ir::Type::I64 => Expression::const_i64(self, value as i64),
+            ir::Type::F32 => Expression::const_f32(self, Ieee32::from_bits(value as u32)),
+            ir::Type::F64 => Expression::const_f64(self, Ieee64::from_bits(value)),
+            _ => panic!("Unsupported type"),
+        };
+
+        let num = unsafe { BinaryenGetNumGlobals(self.0) };
+        let global = unsafe { BinaryenAddGlobal(self.0, std::ptr::null(), b_ty, mutable, init.1) };
+        assert!(!global.is_null());
+        ir::Global::from(num)
+    }
+
+    pub fn add_table(&self, ty: ir::Type, init: usize, max: Option<u32>) -> ir::Table {
+        let ty = Type::from(ty).to_binaryen();
+        let num = unsafe { BinaryenGetNumTables(self.0) };
+        let max = max.unwrap_or(0);
+        let table = unsafe {
+            BinaryenAddTable(
+                self.0,
+                std::ptr::null(),
+                init as BinaryenIndex,
+                max as BinaryenIndex,
+                ty,
+            )
+        };
+        assert!(!table.is_null());
+        ir::Table::from(num)
+    }
+
+    pub fn add_table_elem(&self, table: ir::Table, index: usize, elt: ir::Func) {
+        let table_name = unsafe {
+            BinaryenTableGetName(BinaryenGetTableByIndex(
+                self.0,
+                table.index() as BinaryenIndex,
+            ))
+        };
+        let func_name = unsafe {
+            BinaryenFunctionGetName(BinaryenGetFunctionByIndex(
+                self.0,
+                elt.index() as BinaryenIndex,
+            ))
+        };
+        let offset = Expression::const_i32(self, index as i32);
+        let seg = unsafe {
+            BinaryenAddActiveElementSegment(
+                self.0,
+                table_name,
+                std::ptr::null(),
+                &func_name as *const *const c_char,
+                1,
+                offset.1,
+            )
+        };
+        assert!(!seg.is_null());
+    }
+
+    pub fn add_mem(
+        &self,
+        init_pages: usize,
+        max_pages: Option<usize>,
+        segments: &[ir::MemorySegment],
+    ) -> ir::Memory {
+        let seg_passive = vec![false; segments.len()];
+        let seg_offset = segments
+            .iter()
+            .map(|seg| Expression::const_i32(self, seg.offset as i32).1)
+            .collect::<Vec<_>>();
+        let seg_data = segments
+            .iter()
+            .map(|seg| seg.data.as_ptr() as *const c_char)
+            .collect::<Vec<_>>();
+        let seg_size = segments
+            .iter()
+            .map(|seg| seg.data.len() as BinaryenIndex)
+            .collect::<Vec<_>>();
+
+        // Binaryen does not support multi-memory.
+        unsafe {
+            BinaryenSetMemory(
+                self.0,
+                init_pages as BinaryenIndex,
+                max_pages.unwrap_or(0) as BinaryenIndex,
+                std::ptr::null(),
+                seg_data.as_ptr(),
+                seg_passive.as_ptr(),
+                seg_offset.as_ptr(),
+                seg_size.as_ptr(),
+                segments.len() as BinaryenIndex,
+                false,
+            );
+        }
+        ir::Memory::from(0)
+    }
+
+    pub fn add_table_import(&self, table: ir::Table, module: &str, name: &str) {
+        let table_name = unsafe {
+            BinaryenTableGetName(BinaryenGetTableByIndex(
+                self.0,
+                table.index() as BinaryenIndex,
+            ))
+        };
+        let c_module = std::ffi::CString::new(module).unwrap();
+        let c_name = std::ffi::CString::new(name).unwrap();
+        unsafe {
+            BinaryenAddTableImport(self.0, table_name, c_module.as_ptr(), c_name.as_ptr());
+        }
+    }
+
+    pub fn add_func_import(
+        &self,
+        func: ir::Func,
+        module: &str,
+        name: &str,
+        params: &[ir::Type],
+        results: &[ir::Type],
+    ) {
+        let func_name = unsafe {
+            BinaryenFunctionGetName(BinaryenGetFunctionByIndex(
+                self.0,
+                func.index() as BinaryenIndex,
+            ))
+        };
+        let c_module = std::ffi::CString::new(module).unwrap();
+        let c_name = std::ffi::CString::new(name).unwrap();
+        let params = tys_to_binaryen(params.iter().copied());
+        let results = tys_to_binaryen(results.iter().copied());
+        unsafe {
+            BinaryenAddFunctionImport(
+                self.0,
+                func_name,
+                c_module.as_ptr(),
+                c_name.as_ptr(),
+                params,
+                results,
+            );
+        }
+    }
+
+    pub fn add_global_import(
+        &self,
+        global: ir::Global,
+        module: &str,
+        name: &str,
+        ty: ir::Type,
+        mutable: bool,
+    ) {
+        let global_name = unsafe {
+            BinaryenGlobalGetName(BinaryenGetGlobalByIndex(
+                self.0,
+                global.index() as BinaryenIndex,
+            ))
+        };
+        let c_module = std::ffi::CString::new(module).unwrap();
+        let c_name = std::ffi::CString::new(name).unwrap();
+        let ty = Type::from(ty).to_binaryen();
+        unsafe {
+            BinaryenAddGlobalImport(
+                self.0,
+                global_name,
+                c_module.as_ptr(),
+                c_name.as_ptr(),
+                ty,
+                mutable,
+            );
+        }
+    }
 }
 
 impl Drop for Module {
@@ -708,6 +888,8 @@ type BinaryenExport = *const c_void;
 type BinaryenRelooper = *const c_void;
 type BinaryenRelooperBlock = *const c_void;
 type BinaryenTable = *const c_void;
+type BinaryenGlobal = *const c_void;
+type BinaryenElementSegment = *const c_void;
 
 #[repr(C)]
 struct BinaryenModuleAllocateAndWriteResult {
@@ -787,6 +969,7 @@ impl Drop for Relooper {
 #[link(name = "binaryen")]
 extern "C" {
     fn BinaryenModuleRead(data: *const u8, len: usize) -> BinaryenModule;
+    fn BinaryenModuleCreate() -> BinaryenModule;
     fn BinaryenModuleDispose(ptr: BinaryenModule);
     fn BinaryenModuleAllocateAndWrite(
         ptr: BinaryenModule,
@@ -1373,6 +1556,77 @@ extern "C" {
     fn BinaryenRefAsData() -> BinaryenOp;
     fn BinaryenRefAsI31() -> BinaryenOp;
 
+    fn BinaryenAddGlobal(
+        module: BinaryenModule,
+        name: *const c_char,
+        ty: BinaryenType,
+        mutable: bool,
+        init: BinaryenExpression,
+    ) -> BinaryenGlobal;
+    fn BinaryenGetNumGlobals(module: BinaryenModule) -> BinaryenIndex;
+
+    fn BinaryenAddTable(
+        module: BinaryenModule,
+        name: *const c_char,
+        initial: BinaryenIndex,
+        max: BinaryenIndex,
+        ty: BinaryenType,
+    ) -> BinaryenTable;
+    fn BinaryenGetNumTables(module: BinaryenModule) -> BinaryenIndex;
+
+    fn BinaryenAddActiveElementSegment(
+        module: BinaryenModule,
+        table: *const c_char,
+        name: *const c_char,
+        func_names: *const *const c_char,
+        num_funcs: BinaryenIndex,
+        offset: BinaryenExpression,
+    ) -> BinaryenElementSegment;
+
+    fn BinaryenSetMemory(
+        module: BinaryenModule,
+        init: BinaryenIndex,
+        max: BinaryenIndex,
+        export_name: *const c_char,
+        segments: *const *const c_char,
+        seg_passive: *const bool,
+        seg_offsets: *const BinaryenExpression,
+        sizes: *const BinaryenIndex,
+        n_segments: BinaryenIndex,
+        shared: bool,
+    );
+
+    fn BinaryenAddTableImport(
+        module: BinaryenModule,
+        name: *const c_char,
+        extern_module: *const c_char,
+        extern_name: *const c_char,
+    );
+    fn BinaryenAddMemoryImport(
+        module: BinaryenModule,
+        name: *const c_char,
+        extern_module: *const c_char,
+        extern_name: *const c_char,
+    );
+    fn BinaryenAddGlobalImport(
+        module: BinaryenModule,
+        name: *const c_char,
+        extern_module: *const c_char,
+        extern_name: *const c_char,
+        ty: BinaryenType,
+        mutable: bool,
+    );
+    fn BinaryenAddFunctionImport(
+        module: BinaryenModule,
+        name: *const c_char,
+        extern_module: *const c_char,
+        extern_name: *const c_char,
+        params: BinaryenType,
+        results: BinaryenType,
+    );
+
+    fn BinaryenGlobalGetName(global: BinaryenGlobal) -> *const c_char;
+    fn BinaryenGetGlobalByIndex(module: BinaryenModule, index: BinaryenIndex) -> BinaryenGlobal;
 }
 
 #[repr(C)]
diff --git a/src/backend/lower.rs b/src/backend/lower.rs
index 8860a7f..6d79759 100644
--- a/src/backend/lower.rs
+++ b/src/backend/lower.rs
@@ -1,10 +1,84 @@
 use crate::backend::binaryen;
 use crate::entity::EntityRef;
+use crate::ir::ImportKind;
 use crate::ir::*;
 use crate::Operator;
+use anyhow::Result;
 use fxhash::FxHashMap;
 use std::collections::BTreeMap;
 
+pub(crate) fn lower(module: &Module) -> Result<binaryen::Module> {
+    let into_mod = binaryen::Module::new()?;
+
+    // Create globals.
+    for (global, data) in module.globals() {
+        let new_global = into_mod.add_global(data.ty, data.mutable, data.value);
+        assert_eq!(new_global, global);
+    }
+
+    // Create tables.
+    for (table, data) in module.tables() {
+        let new_table = into_mod.add_table(
+            data.ty,
+            data.func_elements
+                .as_ref()
+                .map(|elems| elems.len())
+                .unwrap_or(0),
+            data.max,
+        );
+        assert_eq!(new_table, table);
+        if let Some(elts) = data.func_elements.as_ref() {
+            for (i, &elt) in elts.iter().enumerate() {
+                if elt.is_valid() {
+                    into_mod.add_table_elem(new_table, i, elt);
+                }
+            }
+        }
+    }
+
+    // Create memories.
+    for (mem, data) in module.memories() {
+        let new_mem = into_mod.add_mem(data.initial_pages, data.maximum_pages, &data.segments[..]);
+        assert_eq!(new_mem, mem);
+    }
+
+    // Create function bodies.
+
+    // Create imports.
+    for import in module.imports() {
+        match &import.kind {
+            &ImportKind::Table(table) => {
+                into_mod.add_table_import(table, &import.module[..], &import.name[..]);
+            }
+            &ImportKind::Func(func) => {
+                let sig = module.func(func).sig();
+                let sigdata = module.signature(sig);
+                into_mod.add_func_import(
+                    func,
+                    &import.module[..],
+                    &import.name[..],
+                    &sigdata.params[..],
+                    &sigdata.returns[..],
+                );
+            }
+            &ImportKind::Global(global) => {
+                let globdata = module.global(global);
+                into_mod.add_global_import(
+                    global,
+                    &import.module[..],
+                    &import.name[..],
+                    globdata.ty,
+                    globdata.mutable,
+                );
+            }
+        }
+    }
+
+    // Create exports.
+
+    Ok(into_mod)
+}
+
 /// Creates a body expression for a function. Returns that expression,
 /// and new locals (as their types) that were created as temporaries
 /// and need to be appended to `body.locals`.
diff --git a/src/backend/mod.rs b/src/backend/mod.rs
index d75646a..7020fb8 100644
--- a/src/backend/mod.rs
+++ b/src/backend/mod.rs
@@ -2,3 +2,4 @@
 
 pub mod binaryen;
 pub mod lower;
+
diff --git a/src/frontend.rs b/src/frontend.rs
index a4cc719..d569b14 100644
--- a/src/frontend.rs
+++ b/src/frontend.rs
@@ -78,12 +78,17 @@ fn handle_payload<'a>(
                         Some(ImportKind::Func(func))
                     }
                     ImportSectionEntryType::Global(ty) => {
+                        let mutable = ty.mutable;
                         let ty = ty.content_type.into();
-                        let global = module.frontend_add_global(GlobalData { ty, value: None });
+                        let global = module.frontend_add_global(GlobalData {
+                            ty,
+                            value: None,
+                            mutable,
+                        });
                         Some(ImportKind::Global(global))
                     }
                     ImportSectionEntryType::Table(ty) => {
-                        let table = module.frontend_add_table(ty.element_type.into());
+                        let table = module.frontend_add_table(ty.element_type.into(), None);
                         Some(ImportKind::Table(table))
                     }
                     _ => None,
@@ -100,18 +105,20 @@ fn handle_payload<'a>(
         Payload::GlobalSection(reader) => {
             for global in reader {
                 let global = global?;
+                let mutable = global.ty.mutable;
                 let ty = global.ty.content_type.into();
                 let init_expr = parse_init_expr(&global.init_expr)?;
                 module.frontend_add_global(GlobalData {
                     ty,
                     value: init_expr,
+                    mutable,
                 });
             }
         }
         Payload::TableSection(reader) => {
             for table in reader {
                 let table = table?;
-                module.frontend_add_table(table.element_type.into());
+                module.frontend_add_table(table.element_type.into(), table.maximum);
             }
         }
         Payload::FunctionSection(reader) => {
diff --git a/src/ir/module.rs b/src/ir/module.rs
index 4dcdc3c..eb9ada3 100644
--- a/src/ir/module.rs
+++ b/src/ir/module.rs
@@ -1,9 +1,8 @@
 use super::{Func, FuncDecl, Global, Memory, ModuleDisplay, Signature, Table, Type};
 use crate::entity::EntityVec;
-use crate::frontend;
 use crate::ir::FunctionBody;
+use crate::{backend, frontend};
 use anyhow::Result;
-use fxhash::FxHashSet;
 
 #[derive(Clone, Debug)]
 pub struct Module<'a> {
@@ -15,8 +14,6 @@ pub struct Module<'a> {
     imports: Vec<Import>,
     exports: Vec<Export>,
     memories: EntityVec<Memory, MemoryData>,
-
-    dirty_funcs: FxHashSet<Func>,
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -41,6 +38,7 @@ pub struct MemorySegment {
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct TableData {
     pub ty: Type,
+    pub max: Option<u32>,
     pub func_elements: Option<Vec<Func>>,
 }
 
@@ -48,6 +46,7 @@ pub struct TableData {
 pub struct GlobalData {
     pub ty: Type,
     pub value: Option<u64>,
+    pub mutable: bool,
 }
 
 impl From<&wasmparser::FuncType> for SignatureData {
@@ -134,7 +133,6 @@ impl<'a> Module<'a> {
             imports: vec![],
             exports: vec![],
             memories: EntityVec::default(),
-            dirty_funcs: FxHashSet::default(),
         }
     }
 }
@@ -144,7 +142,6 @@ impl<'a> Module<'a> {
         &self.funcs[id]
     }
     pub fn func_mut<'b>(&'b mut self, id: Func) -> &'b mut FuncDecl {
-        self.dirty_funcs.insert(id);
         &mut self.funcs[id]
     }
     pub fn funcs<'b>(&'b self) -> impl Iterator<Item = (Func, &'b FuncDecl)> {
@@ -190,13 +187,17 @@ impl<'a> Module<'a> {
     pub(crate) fn frontend_add_func(&mut self, body: FuncDecl) -> Func {
         self.funcs.push(body)
     }
-    pub(crate) fn frontend_add_table(&mut self, ty: Type) -> Table {
+    pub(crate) fn frontend_add_table(&mut self, ty: Type, max: Option<u32>) -> Table {
         let func_elements = if ty == Type::FuncRef {
             Some(vec![])
         } else {
             None
         };
-        self.tables.push(TableData { ty, func_elements })
+        self.tables.push(TableData {
+            ty,
+            func_elements,
+            max,
+        })
     }
     pub(crate) fn frontend_add_global(&mut self, global: GlobalData) -> Global {
         self.globals.push(global)
@@ -225,7 +226,8 @@ impl<'a> Module<'a> {
     }
 
     pub fn to_wasm_bytes(&self) -> Result<Vec<u8>> {
-        todo!()
+        let module = backend::lower::lower(self)?;
+        module.write()
     }
 
     pub fn display<'b>(&'b self) -> ModuleDisplay<'b>