refactor(compiler): 拆分 oxide_emit 为独立 emit pass crate（依赖倒置）

crates/oxide_emit/src/class/core.rs

@@ -0,0 +1 @@
+

crates/oxide_emit/src/class/emit.rs

@@ -0,0 +1,124 @@
+use crate::{CompileCtx, Emitter, FunctionBodyContext};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{Class, ClassElement, MethodDefinitionKind, PropertyKey};
+
+impl Emitter {
+    pub(crate) fn emit_class(&self, class: &Class, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let mut constructor_method = None;
+        let mut instance_fields = Vec::new();
+        let mut private_names = Vec::<(String, u32)>::new();
+        let is_derived = class.super_class.is_some();
+
+        for element in &class.body.body {
+            match element {
+                ClassElement::MethodDefinition(method) => {
+                    let method = method.as_ref();
+                    if let PropertyKey::PrivateIdentifier(private) = &method.key {
+                        let name = private.name.as_str().to_string();
+                        if private_names.iter().any(|(existing, _)| existing == &name) {
+                            return Err(format!("duplicate private name #{name}"));
+                        }
+                        let id = ctx.scopes.next_private_name_id;
+                        ctx.scopes.next_private_name_id = ctx.scopes.next_private_name_id.saturating_add(1);
+                        private_names.push((name, id));
+                    }
+                    if method.kind == MethodDefinitionKind::Constructor {
+                        if constructor_method.is_some() {
+                            return Err("duplicate class constructor".into());
+                        }
+                        constructor_method = Some(method);
+                    }
+                }
+                ClassElement::PropertyDefinition(prop) => {
+                    let prop = prop.as_ref();
+                    if let PropertyKey::PrivateIdentifier(private) = &prop.key {
+                        let name = private.name.as_str().to_string();
+                        if private_names.iter().any(|(existing, _)| existing == &name) {
+                            return Err(format!("duplicate private name #{name}"));
+                        }
+                        let id = ctx.scopes.next_private_name_id;
+                        ctx.scopes.next_private_name_id = ctx.scopes.next_private_name_id.saturating_add(1);
+                        private_names.push((name, id));
+                    }
+                    if !prop.r#static {
+                        instance_fields.push(prop);
+                    }
+                }
+                ClassElement::AccessorProperty(_) => return Err("class accessor properties not yet supported".into()),
+                ClassElement::StaticBlock(_) | ClassElement::TSIndexSignature(_) => {}
+            }
+        }
+
+        let (ctor_reg, proto_reg, super_reg) = self.emit_class_header(class, ctx)?;
+        let ctor_name = class.id.as_ref().map(|id| id.name.to_string());
+        let self_binding = ctor_name.as_deref().map(|name| vec![(name, ctor_reg)]).unwrap_or_default();
+        let saved_derived = ctx.in_derived_constructor;
+        let saved_private_names = ctx.scopes.private_name_map.clone();
+        ctx.in_derived_constructor = is_derived;
+        ctx.scopes.private_name_map = private_names.clone();
+
+        let emit_instance_fields = |compiler: &Emitter, field_ctx: &mut CompileCtx| -> Result<(), String> {
+            for field in &instance_fields {
+                if let PropertyKey::PrivateIdentifier(private) = &field.key {
+                    compiler.emit_private_field_init(Operand::This, private.name.as_str(), field.value.as_ref(), field_ctx)?;
+                } else {
+                    compiler.emit_public_field_init(Operand::This, &field.key, field.computed, field.value.as_ref(), field_ctx)?;
+                }
+            }
+            Ok(())
+        };
+
+        let mut ctor_module = if let Some(method) = constructor_method {
+            let (param_names, body_stmts) = self.extract_function_parts(method.value.as_ref())?;
+            self.compile_function_body_with_field_hooks(
+                &param_names,
+                body_stmts,
+                ctx,
+                false,
+                &self_binding,
+                FunctionBodyContext::ClassElement,
+                Some(&emit_instance_fields),
+                is_derived,
+            )?
+        } else {
+            let mut module = self.compile_function_body_with_field_hooks(
+                &[],
+                &[],
+                ctx,
+                false,
+                &self_binding,
+                FunctionBodyContext::ClassElement,
+                Some(&emit_instance_fields),
+                is_derived,
+            )?;
+            if is_derived {
+                module.insts.clear();
+                module.constants.clear();
+                module.n_registers = 1;
+                module.insts.push(Inst::super_call(Operand::None, Operand::None, 0));
+                let mut field_ctx = CompileCtx::new();
+                field_ctx.scopes.private_name_map = private_names.clone();
+                emit_instance_fields(self, &mut field_ctx)?;
+                module.insts.extend(field_ctx.insts);
+                module.constants = field_ctx.constants;
+                module.n_registers = field_ctx.max_regs.max(1);
+                module.insts.push(Inst::new(OpCode::RETURN, Operand::None, Operand::None, Operand::None));
+            }
+            module
+        };
+        ctx.in_derived_constructor = saved_derived;
+        ctor_module.is_class_constructor = true;
+        ctor_module.is_derived_constructor = is_derived;
+        ctor_module.function_name = ctor_name.clone();
+        ctx.nested.push(ctor_module);
+
+        self.emit_class_prototype(ctor_reg, proto_reg, super_reg, ctx.nested.len() as u16, ctx)?;
+        self.emit_class_methods(&class.body.body, ctor_reg, proto_reg, &self_binding, ctx)?;
+        self.emit_class_static_elements(&class.body.body, ctor_reg, ctx)?;
+
+        ctx.scopes.private_name_map = saved_private_names;
+        Ok(ctor_reg)
+    }
+}

crates/oxide_emit/src/class/field.rs

@@ -0,0 +1,40 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::operand::Operand;
+use oxide_parser::{ClassElement, PropertyKey};
+
+impl Emitter {
+    /// Emit static field initializers and static blocks in source order.
+    /// JS class semantics interleave them (e.g. `static x = 1; static {
+    /// this.y = 1 } static z = this.y + 1` must run in that order). Emitting
+    /// all fields before all blocks would make `z` read `y` before it is set.
+    pub(crate) fn emit_class_static_elements(
+        &self, elements: &[ClassElement], ctor_reg: u8, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        let saved_static_this = ctx.static_block_this_reg;
+        ctx.static_block_this_reg = Some(ctor_reg);
+        for element in elements {
+            match element {
+                ClassElement::PropertyDefinition(prop) => {
+                    let prop = prop.as_ref();
+                    if prop.r#static {
+                        if let PropertyKey::PrivateIdentifier(private) = &prop.key {
+                            self.emit_private_field_init(Operand::Reg(ctor_reg as u32), private.name.as_str(), prop.value.as_ref(), ctx)?;
+                        } else {
+                            self.emit_public_field_init(Operand::Reg(ctor_reg as u32), &prop.key, prop.computed, prop.value.as_ref(), ctx)?;
+                        }
+                    }
+                }
+                ClassElement::StaticBlock(block) => {
+                    ctx.push_scope();
+                    for stmt in &block.body {
+                        self.emit_statement(stmt, ctx)?;
+                    }
+                    ctx.pop_scope();
+                }
+                _ => {}
+            }
+        }
+        ctx.static_block_this_reg = saved_static_this;
+        Ok(())
+    }
+}

crates/oxide_emit/src/class/header.rs

@@ -0,0 +1,16 @@
+use crate::{CompileCtx, Emitter};
+
+impl Emitter {
+    pub(crate) fn emit_class_header(
+        &self, class: &oxide_parser::Class, ctx: &mut CompileCtx,
+    ) -> Result<(u8, u8, Option<u8>), String> {
+        let ctor_reg = ctx.alloc_reg();
+        let proto_reg = ctx.alloc_reg();
+        let super_reg = if let Some(super_expr) = &class.super_class {
+            Some(self.emit_expression(super_expr, ctx)?)
+        } else {
+            None
+        };
+        Ok((ctor_reg, proto_reg, super_reg))
+    }
+}

crates/oxide_emit/src/class/method.rs

@@ -0,0 +1,97 @@
+use crate::{CompileCtx, Emitter, FunctionBodyContext};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{ClassElement, MethodDefinitionKind, PropertyKey};
+
+impl Emitter {
+    pub(crate) fn emit_class_methods(
+        &self, elements: &[ClassElement], ctor_reg: u8, proto_reg: u8, self_binding: &[(&str, u8)],
+        ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        for element in elements {
+            match element {
+                ClassElement::MethodDefinition(method) => {
+                    let method = method.as_ref();
+                    if method.kind == MethodDefinitionKind::Constructor {
+                        continue;
+                    }
+                    if matches!(method.key, PropertyKey::PrivateIdentifier(_)) {
+                        let home_reg = if method.r#static { ctor_reg } else { proto_reg };
+                        self.emit_private_method_init(Operand::Reg(home_reg as u32), method, Operand::Reg(home_reg as u32), ctx)?;
+                        continue;
+                    }
+                    let home_reg = if method.r#static { ctor_reg } else { proto_reg };
+                    let key_reg = self.emit_class_key_reg(&method.key, method.computed, ctx)?;
+                    let method_name = if method.computed {
+                        "<computed>".to_string()
+                    } else {
+                        self.class_property_name(&method.key)?
+                    };
+                    let accessor_reg =
+                        self.emit_class_method_function(method, &method_name, Operand::Reg(home_reg as u32), ctx, self_binding)?;
+                    match method.kind {
+                        MethodDefinitionKind::Method => {
+                            if method.computed {
+                                ctx.inst(Inst::new(OpCode::SET_PROP_DYNAMIC, Operand::Reg(home_reg as u32), Operand::Reg(key_reg as u32), Operand::Reg(accessor_reg as u32)));
+                            } else {
+                                ctx.inst(Inst::new(OpCode::SET_PROP, Operand::Reg(home_reg as u32), Operand::Reg(accessor_reg as u32), Operand::Reg(key_reg as u32)));
+                            }
+                        }
+                        MethodDefinitionKind::Get | MethodDefinitionKind::Set => {
+                            if method.computed {
+                                return Err("computed class accessors not yet supported".into());
+                            }
+                            let undef_reg = self.emit_undefined(ctx);
+                            let (get_reg, set_reg) = if method.kind == MethodDefinitionKind::Get {
+                                (accessor_reg, undef_reg)
+                            } else {
+                                (undef_reg, accessor_reg)
+                            };
+                            let key_name = self.class_property_name(&method.key)?;
+                            let key_idx = ctx.add_constant(Constant::String(key_name));
+                            ctx.inst(Inst::define_accessor(
+                                Operand::Reg(home_reg as u32),
+                                Operand::Reg(get_reg as u32),
+                                Operand::Reg(set_reg as u32),
+                                key_idx as u32,
+                            ));
+                        }
+                        MethodDefinitionKind::Constructor => continue,
+                    }
+                }
+                _ => {}
+            }
+        }
+        Ok(())
+    }
+
+    pub(crate) fn emit_class_method_function(
+        &self, method: &oxide_parser::MethodDefinition, method_name: &str, home_reg: Operand, ctx: &mut CompileCtx,
+        self_binding: &[(&str, u8)],
+    ) -> Result<u8, String> {
+        let (param_names, body_stmts) = self.extract_function_parts(method.value.as_ref())?;
+        let saved_instance = ctx.in_instance_method;
+        let saved_static = ctx.in_static_method;
+        ctx.in_instance_method = !method.r#static;
+        ctx.in_static_method = method.r#static;
+        let mut method_module = self.compile_function_body_with_bindings(
+            &param_names,
+            body_stmts,
+            ctx,
+            false,
+            self_binding,
+            FunctionBodyContext::ClassElement,
+        )?;
+        ctx.in_instance_method = saved_instance;
+        ctx.in_static_method = saved_static;
+        method_module.function_name = Some(method_name.to_string());
+        method_module.needs_home_object = true;
+        ctx.nested.push(method_module);
+        let method_reg = ctx.alloc_reg();
+        ctx.inst(Inst::create_closure(Operand::Reg(method_reg as u32), ctx.nested.len() as u16));
+        ctx.inst(Inst::new(OpCode::SET_HOME_OBJECT, Operand::Reg(method_reg as u32), home_reg, Operand::None));
+        Ok(method_reg)
+    }
+}

crates/oxide_emit/src/class/mod.rs

@@ -0,0 +1,6 @@
+pub mod core;
+pub mod emit;
+pub mod field;
+pub mod header;
+pub mod method;
+pub mod prototype;

crates/oxide_emit/src/class/prototype.rs

@@ -0,0 +1,35 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+
+impl Emitter {
+    pub(crate) fn emit_class_prototype(
+        &self, ctor_reg: u8, proto_reg: u8, super_reg: Option<u8>, sub_idx: u16, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        ctx.inst(Inst::create_closure(Operand::Reg(ctor_reg as u32), sub_idx));
+        ctx.inst(Inst::new(OpCode::NEW_OBJECT, Operand::Reg(proto_reg as u32), Operand::None, Operand::None));
+        if let Some(super_reg) = super_reg {
+            let proto_key_idx = ctx.add_constant(Constant::String("prototype".to_string()));
+            let parent_proto_key_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(parent_proto_key_reg as u32), proto_key_idx));
+            let parent_proto_reg = ctx.alloc_reg();
+            ctx.inst(Inst::new(OpCode::GET_PROP, Operand::Reg(super_reg as u32), Operand::Reg(parent_proto_reg as u32), Operand::Reg(parent_proto_key_reg as u32)));
+            let proto_link_idx = ctx.add_constant(Constant::String("__proto__".to_string()));
+            let proto_link_key_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(proto_link_key_reg as u32), proto_link_idx));
+            ctx.inst(Inst::new(OpCode::SET_PROP, Operand::Reg(proto_reg as u32), Operand::Reg(parent_proto_reg as u32), Operand::Reg(proto_link_key_reg as u32)));
+            ctx.inst(Inst::new(OpCode::SET_PROP, Operand::Reg(ctor_reg as u32), Operand::Reg(super_reg as u32), Operand::Reg(proto_link_key_reg as u32)));
+        }
+        let ctor_key_idx = ctx.add_constant(Constant::String("constructor".to_string()));
+        let ctor_key_reg = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(ctor_key_reg as u32), ctor_key_idx));
+        ctx.inst(Inst::new(OpCode::SET_PROP, Operand::Reg(proto_reg as u32), Operand::Reg(ctor_reg as u32), Operand::Reg(ctor_key_reg as u32)));
+        let proto_key_idx = ctx.add_constant(Constant::String("prototype".to_string()));
+        let proto_key_reg = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(proto_key_reg as u32), proto_key_idx));
+        ctx.inst(Inst::new(OpCode::SET_PROP, Operand::Reg(ctor_reg as u32), Operand::Reg(proto_reg as u32), Operand::Reg(proto_key_reg as u32)));
+        Ok(())
+    }
+}

crates/oxide_emit/src/closure.rs

@@ -0,0 +1,517 @@
+use std::collections::{BTreeMap, HashSet};
+
+use oxide_bytecode::module::UpvalueCapture;
+use oxide_parser::{Expression, Statement};
+
+use crate::Emitter;
+
+impl Emitter {
+
+    fn collect_fn_param_names(&self, params: &oxide_parser::FormalParameters) -> HashSet<String> {
+        let mut names = HashSet::new();
+        for p in &params.items {
+            if let oxide_parser::BindingPattern::BindingIdentifier(bi) = &p.pattern {
+                names.insert(bi.name.to_string());
+            }
+        }
+        names
+    }
+
+    /// 收集当前函数作用域声明的绑定名（参数 + 变量/函数声明，含嵌套 block，不含嵌套函数体）。
+    pub(crate) fn collect_own_binding_names(&self, param_names: &[&str], stmts: &[Statement]) -> HashSet<String> {
+        let mut names = HashSet::new();
+        for p in param_names {
+            names.insert(p.to_string());
+        }
+        self.collect_decl_names_stmt(stmts, &mut names);
+        names
+    }
+
+    fn collect_decl_names_stmt(&self, stmts: &[Statement], out: &mut HashSet<String>) {
+        for stmt in stmts {
+            match stmt {
+                Statement::VariableDeclaration(vd) => {
+                    for d in &vd.declarations {
+                        if let oxide_parser::BindingPattern::BindingIdentifier(bi) = &d.id {
+                            out.insert(bi.name.to_string());
+                        }
+                    }
+                }
+                Statement::FunctionDeclaration(fd) => {
+                    if let Some(id) = &fd.id {
+                        out.insert(id.name.to_string());
+                    }
+                }
+                Statement::BlockStatement(b) => self.collect_decl_names_stmt(&b.body, out),
+                Statement::IfStatement(is) => {
+                    self.collect_decl_names_stmt(std::slice::from_ref(&is.consequent), out);
+                    if let Some(alt) = &is.alternate {
+                        self.collect_decl_names_stmt(std::slice::from_ref(alt), out);
+                    }
+                }
+                Statement::WhileStatement(w) => self.collect_decl_names_stmt(std::slice::from_ref(&w.body), out),
+                Statement::DoWhileStatement(d) => self.collect_decl_names_stmt(std::slice::from_ref(&d.body), out),
+                Statement::ForStatement(f) => {
+                    if let Some(oxide_parser::ForStatementInit::VariableDeclaration(vd)) = &f.init {
+                        for d in &vd.declarations {
+                            if let oxide_parser::BindingPattern::BindingIdentifier(bi) = &d.id {
+                                out.insert(bi.name.to_string());
+                            }
+                        }
+                    }
+                    self.collect_decl_names_stmt(std::slice::from_ref(&f.body), out);
+                }
+                Statement::SwitchStatement(sw) => {
+                    for case in &sw.cases {
+                        self.collect_decl_names_stmt(&case.consequent, out);
+                    }
+                }
+                Statement::TryStatement(ts) => {
+                    self.collect_decl_names_stmt(&ts.block.body, out);
+                    if let Some(h) = &ts.handler {
+                        self.collect_decl_names_stmt(&h.body.body, out);
+                    }
+                    if let Some(f) = &ts.finalizer {
+                        self.collect_decl_names_stmt(&f.body, out);
+                    }
+                }
+                Statement::LabeledStatement(ls) => self.collect_decl_names_stmt(std::slice::from_ref(&ls.body), out),
+                _ => {}
+            }
+        }
+    }
+
+    /// 扫描 stmts 内（含任意深度嵌套函数）对 `ref_set` 的引用，写入 out。
+    /// 递归进入嵌套函数时累加其局部绑定为遮蔽集，避免把内层局部误判为捕获。
+    fn collect_capture_names(&self, stmts: &[Statement], ref_set: &HashSet<String>, out: &mut HashSet<String>) {
+        let shadow = HashSet::new();
+        self.collect_capture_names_shadowed(stmts, ref_set, &shadow, out);
+    }
+
+    fn collect_capture_names_shadowed(
+        &self, stmts: &[Statement], ref_set: &HashSet<String>, shadow: &HashSet<String>, out: &mut HashSet<String>,
+    ) {
+        for stmt in stmts {
+            self.collect_capture_names_stmt(stmt, ref_set, shadow, out);
+        }
+    }
+
+    fn collect_capture_names_stmt(
+        &self, stmt: &Statement, ref_set: &HashSet<String>, shadow: &HashSet<String>, out: &mut HashSet<String>,
+    ) {
+        match stmt {
+            Statement::ExpressionStatement(es) => self.collect_capture_names_expr(&es.expression, ref_set, shadow, out),
+            Statement::ReturnStatement(rs) => {
+                if let Some(a) = &rs.argument {
+                    self.collect_capture_names_expr(a, ref_set, shadow, out);
+                }
+            }
+            Statement::VariableDeclaration(vd) => {
+                for d in &vd.declarations {
+                    if let Some(init) = &d.init {
+                        self.collect_capture_names_expr(init, ref_set, shadow, out);
+                    }
+                }
+            }
+            Statement::FunctionDeclaration(fd) => {
+                let body: &[Statement] = fd.body.as_ref().map(|b| &b.statements[..]).unwrap_or(&[]);
+                let mut inner = shadow.clone();
+                inner.extend(self.collect_fn_param_names(&fd.params));
+                inner.extend(self.collect_own_binding_names(&[], body));
+                self.collect_capture_names_shadowed(body, ref_set, &inner, out);
+            }
+            Statement::IfStatement(is) => {
+                self.collect_capture_names_expr(&is.test, ref_set, shadow, out);
+                self.collect_capture_names_stmt(&is.consequent, ref_set, shadow, out);
+                if let Some(alt) = &is.alternate {
+                    self.collect_capture_names_stmt(alt, ref_set, shadow, out);
+                }
+            }
+            Statement::ForStatement(fs) => {
+                if let Some(init) = &fs.init {
+                    if let Some(e) = init.as_expression() {
+                        self.collect_capture_names_expr(e, ref_set, shadow, out);
+                    }
+                    if let oxide_parser::ForStatementInit::VariableDeclaration(vd) = init {
+                        for d in &vd.declarations {
+                            if let Some(i) = &d.init {
+                                self.collect_capture_names_expr(i, ref_set, shadow, out);
+                            }
+                        }
+                    }
+                }
+                if let Some(t) = &fs.test {
+                    self.collect_capture_names_expr(t, ref_set, shadow, out);
+                }
+                if let Some(u) = &fs.update {
+                    self.collect_capture_names_expr(u, ref_set, shadow, out);
+                }
+                self.collect_capture_names_stmt(&fs.body, ref_set, shadow, out);
+            }
+            Statement::WhileStatement(w) => {
+                self.collect_capture_names_expr(&w.test, ref_set, shadow, out);
+                self.collect_capture_names_stmt(&w.body, ref_set, shadow, out);
+            }
+            Statement::DoWhileStatement(d) => {
+                self.collect_capture_names_stmt(&d.body, ref_set, shadow, out);
+                self.collect_capture_names_expr(&d.test, ref_set, shadow, out);
+            }
+            Statement::ForInStatement(fi) => {
+                self.collect_capture_names_expr(&fi.right, ref_set, shadow, out);
+                self.collect_capture_names_stmt(&fi.body, ref_set, shadow, out);
+            }
+            Statement::ForOfStatement(fo) => {
+                self.collect_capture_names_expr(&fo.right, ref_set, shadow, out);
+                self.collect_capture_names_stmt(&fo.body, ref_set, shadow, out);
+            }
+            Statement::BlockStatement(b) => self.collect_capture_names_shadowed(&b.body, ref_set, shadow, out),
+            Statement::TryStatement(ts) => {
+                for s in &ts.block.body {
+                    self.collect_capture_names_stmt(s, ref_set, shadow, out);
+                }
+                if let Some(h) = &ts.handler {
+                    for s in &h.body.body {
+                        self.collect_capture_names_stmt(s, ref_set, shadow, out);
+                    }
+                }
+                if let Some(f) = &ts.finalizer {
+                    for s in &f.body {
+                        self.collect_capture_names_stmt(s, ref_set, shadow, out);
+                    }
+                }
+            }
+            Statement::ThrowStatement(ts) => self.collect_capture_names_expr(&ts.argument, ref_set, shadow, out),
+            Statement::SwitchStatement(sw) => {
+                self.collect_capture_names_expr(&sw.discriminant, ref_set, shadow, out);
+                for case in &sw.cases {
+                    for s in &case.consequent {
+                        self.collect_capture_names_stmt(s, ref_set, shadow, out);
+                    }
+                }
+            }
+            Statement::LabeledStatement(ls) => self.collect_capture_names_stmt(&ls.body, ref_set, shadow, out),
+            _ => {}
+        }
+    }
+
+    fn collect_capture_names_expr(
+        &self, expr: &Expression, ref_set: &HashSet<String>, shadow: &HashSet<String>, out: &mut HashSet<String>,
+    ) {
+        match expr {
+            Expression::Identifier(id) => {
+                let name = id.name.as_str();
+                if ref_set.contains(name) && !shadow.contains(name) {
+                    out.insert(id.name.to_string());
+                }
+            }
+            Expression::AssignmentExpression(ae) => {
+                if let oxide_parser::AssignmentTarget::AssignmentTargetIdentifier(ati) = &ae.left {
+                    let name = ati.name.as_str();
+                    if ref_set.contains(name) && !shadow.contains(name) {
+                        out.insert(ati.name.to_string());
+                    }
+                }
+                self.collect_capture_names_expr(&ae.right, ref_set, shadow, out);
+            }
+            Expression::UpdateExpression(ue) => {
+                if let oxide_parser::SimpleAssignmentTarget::AssignmentTargetIdentifier(ati) = &ue.argument {
+                    let name = ati.name.as_str();
+                    if ref_set.contains(name) && !shadow.contains(name) {
+                        out.insert(ati.name.to_string());
+                    }
+                }
+            }
+            Expression::FunctionExpression(fe) => {
+                let body: &[Statement] = fe.body.as_ref().map(|b| &b.statements[..]).unwrap_or(&[]);
+                let mut inner = shadow.clone();
+                inner.extend(self.collect_fn_param_names(&fe.params));
+                inner.extend(self.collect_own_binding_names(&[], body));
+                self.collect_capture_names_shadowed(body, ref_set, &inner, out);
+            }
+            Expression::ArrowFunctionExpression(ae) => {
+                let mut inner = shadow.clone();
+                inner.extend(self.collect_fn_param_names(&ae.params));
+                inner.extend(self.collect_own_binding_names(&[], &ae.body.statements));
+                self.collect_capture_names_shadowed(&ae.body.statements, ref_set, &inner, out);
+            }
+            Expression::BinaryExpression(be) => {
+                self.collect_capture_names_expr(&be.left, ref_set, shadow, out);
+                self.collect_capture_names_expr(&be.right, ref_set, shadow, out);
+            }
+            Expression::UnaryExpression(ue) => self.collect_capture_names_expr(&ue.argument, ref_set, shadow, out),
+            Expression::CallExpression(ce) => {
+                self.collect_capture_names_expr(&ce.callee, ref_set, shadow, out);
+                for a in &ce.arguments {
+                    if let Some(e) = a.as_expression() {
+                        self.collect_capture_names_expr(e, ref_set, shadow, out);
+                    }
+                }
+            }
+            Expression::NewExpression(ne) => {
+                self.collect_capture_names_expr(&ne.callee, ref_set, shadow, out);
+                for a in &ne.arguments {
+                    if let Some(e) = a.as_expression() {
+                        self.collect_capture_names_expr(e, ref_set, shadow, out);
+                    }
+                }
+            }
+            Expression::SequenceExpression(se) => {
+                for e in &se.expressions {
+                    self.collect_capture_names_expr(e, ref_set, shadow, out);
+                }
+            }
+            Expression::ConditionalExpression(ce) => {
+                self.collect_capture_names_expr(&ce.test, ref_set, shadow, out);
+                self.collect_capture_names_expr(&ce.consequent, ref_set, shadow, out);
+                self.collect_capture_names_expr(&ce.alternate, ref_set, shadow, out);
+            }
+            Expression::ArrayExpression(ae) => {
+                for e in &ae.elements {
+                    if let Some(e) = e.as_expression() {
+                        self.collect_capture_names_expr(e, ref_set, shadow, out);
+                    }
+                }
+            }
+            Expression::LogicalExpression(le) => {
+                self.collect_capture_names_expr(&le.left, ref_set, shadow, out);
+                self.collect_capture_names_expr(&le.right, ref_set, shadow, out);
+            }
+            Expression::ComputedMemberExpression(m) => {
+                self.collect_capture_names_expr(&m.object, ref_set, shadow, out);
+                self.collect_capture_names_expr(&m.expression, ref_set, shadow, out);
+            }
+            Expression::StaticMemberExpression(m) => self.collect_capture_names_expr(&m.object, ref_set, shadow, out),
+            Expression::PrivateFieldExpression(m) => self.collect_capture_names_expr(&m.object, ref_set, shadow, out),
+            Expression::ParenthesizedExpression(p) => self.collect_capture_names_expr(&p.expression, ref_set, shadow, out),
+            Expression::TemplateLiteral(tl) => {
+                for e in &tl.expressions {
+                    self.collect_capture_names_expr(e, ref_set, shadow, out);
+                }
+            }
+            Expression::TaggedTemplateExpression(tt) => {
+                self.collect_capture_names_expr(&tt.tag, ref_set, shadow, out);
+                for e in &tt.quasi.expressions {
+                    self.collect_capture_names_expr(e, ref_set, shadow, out);
+                }
+            }
+            Expression::ObjectExpression(o) => {
+                for prop in &o.properties {
+                    if let oxide_parser::ObjectPropertyKind::ObjectProperty(p) = prop {
+                        self.collect_capture_names_expr(&p.value, ref_set, shadow, out);
+                    }
+                }
+            }
+            Expression::ChainExpression(c) => self.collect_capture_names_chain(&c.expression, ref_set, shadow, out),
+            _ => {}
+        }
+    }
+
+    fn collect_capture_names_chain(
+        &self, element: &oxide_parser::ChainElement, ref_set: &HashSet<String>, shadow: &HashSet<String>,
+        out: &mut HashSet<String>,
+    ) {
+        match element {
+            oxide_parser::ChainElement::StaticMemberExpression(m) => {
+                self.collect_capture_names_expr(&m.object, ref_set, shadow, out);
+            }
+            oxide_parser::ChainElement::ComputedMemberExpression(m) => {
+                self.collect_capture_names_expr(&m.object, ref_set, shadow, out);
+                self.collect_capture_names_expr(&m.expression, ref_set, shadow, out);
+            }
+            oxide_parser::ChainElement::PrivateFieldExpression(m) => {
+                self.collect_capture_names_expr(&m.object, ref_set, shadow, out);
+            }
+            oxide_parser::ChainElement::CallExpression(call) => {
+                self.collect_capture_names_expr(&call.callee, ref_set, shadow, out);
+                for a in &call.arguments {
+                    if let Some(e) = a.as_expression() {
+                        self.collect_capture_names_expr(e, ref_set, shadow, out);
+                    }
+                }
+            }
+            _ => {}
+        }
+    }
+
+    /// 分析本函数：哪些绑定被任意深度嵌套函数捕获 → captured_bindings。
+    pub(crate) fn collect_captured_bindings(&self, stmts: &[Statement], own: &HashSet<String>) -> BTreeMap<String, u8> {
+        let mut names = HashSet::new();
+        for stmt in stmts {
+            self.collect_captured_stmt(stmt, own, &mut names);
+        }
+        // 名字排序分配 cell_idx（稳定跨 run，父 MAKE_CELL 与子 upvalue 统一引用）
+        let mut sorted: Vec<String> = names.into_iter().collect();
+        sorted.sort();
+        sorted
+            .into_iter()
+            .enumerate()
+            .map(|(i, n)| (n, i as u8))
+            .collect()
+    }
+
+    /// 只从嵌套函数节点进入扫描（本函数直接引用不算捕获）。
+    fn collect_captured_stmt(&self, stmt: &Statement, own: &HashSet<String>, out: &mut HashSet<String>) {
+        match stmt {
+            Statement::FunctionDeclaration(fd) => {
+                let body: &[Statement] = fd.body.as_ref().map(|b| &b.statements[..]).unwrap_or(&[]);
+                self.collect_capture_names(body, own, out);
+            }
+            Statement::ExpressionStatement(es) => self.collect_captured_expr(&es.expression, own, out),
+            Statement::ReturnStatement(rs) => {
+                if let Some(a) = &rs.argument {
+                    self.collect_captured_expr(a, own, out);
+                }
+            }
+            Statement::VariableDeclaration(vd) => {
+                for d in &vd.declarations {
+                    if let Some(init) = &d.init {
+                        self.collect_captured_expr(init, own, out);
+                    }
+                }
+            }
+            Statement::IfStatement(is) => {
+                self.collect_captured_expr(&is.test, own, out);
+                self.collect_captured_stmt(&is.consequent, own, out);
+                if let Some(alt) = &is.alternate {
+                    self.collect_captured_stmt(alt, own, out);
+                }
+            }
+            Statement::ForStatement(fs) => {
+                if let Some(init) = &fs.init {
+                    if let Some(e) = init.as_expression() {
+                        self.collect_captured_expr(e, own, out);
+                    }
+                }
+                if let Some(t) = &fs.test {
+                    self.collect_captured_expr(t, own, out);
+                }
+                if let Some(u) = &fs.update {
+                    self.collect_captured_expr(u, own, out);
+                }
+                self.collect_captured_stmt(&fs.body, own, out);
+            }
+            Statement::WhileStatement(w) => {
+                self.collect_captured_expr(&w.test, own, out);
+                self.collect_captured_stmt(&w.body, own, out);
+            }
+            Statement::DoWhileStatement(d) => {
+                self.collect_captured_stmt(&d.body, own, out);
+                self.collect_captured_expr(&d.test, own, out);
+            }
+            Statement::ForInStatement(fi) => {
+                self.collect_captured_expr(&fi.right, own, out);
+                self.collect_captured_stmt(&fi.body, own, out);
+            }
+            Statement::ForOfStatement(fo) => {
+                self.collect_captured_expr(&fo.right, own, out);
+                self.collect_captured_stmt(&fo.body, own, out);
+            }
+            Statement::BlockStatement(b) => {
+                for s in &b.body {
+                    self.collect_captured_stmt(s, own, out);
+                }
+            }
+            Statement::TryStatement(ts) => {
+                for s in &ts.block.body {
+                    self.collect_captured_stmt(s, own, out);
+                }
+                if let Some(h) = &ts.handler {
+                    for s in &h.body.body {
+                        self.collect_captured_stmt(s, own, out);
+                    }
+                }
+                if let Some(f) = &ts.finalizer {
+                    for s in &f.body {
+                        self.collect_captured_stmt(s, own, out);
+                    }
+                }
+            }
+            Statement::ThrowStatement(ts) => self.collect_captured_expr(&ts.argument, own, out),
+            Statement::SwitchStatement(sw) => {
+                self.collect_captured_expr(&sw.discriminant, own, out);
+                for case in &sw.cases {
+                    for s in &case.consequent {
+                        self.collect_captured_stmt(s, own, out);
+                    }
+                }
+            }
+            Statement::LabeledStatement(ls) => self.collect_captured_stmt(&ls.body, own, out),
+            _ => {}
+        }
+    }
+
+    fn collect_captured_expr(&self, expr: &Expression, own: &HashSet<String>, out: &mut HashSet<String>) {
+        match expr {
+            Expression::FunctionExpression(fe) => {
+                let body: &[Statement] = fe.body.as_ref().map(|b| &b.statements[..]).unwrap_or(&[]);
+                let mut inner = self.collect_fn_param_names(&fe.params);
+                inner.extend(self.collect_own_binding_names(&[], body));
+                self.collect_capture_names_shadowed(body, own, &inner, out);
+            }
+            Expression::ArrowFunctionExpression(ae) => {
+                let mut inner = self.collect_fn_param_names(&ae.params);
+                inner.extend(self.collect_own_binding_names(&[], &ae.body.statements));
+                self.collect_capture_names_shadowed(&ae.body.statements, own, &inner, out);
+            }
+            Expression::CallExpression(ce) => {
+                self.collect_captured_expr(&ce.callee, own, out);
+                for a in &ce.arguments {
+                    if let Some(e) = a.as_expression() {
+                        self.collect_captured_expr(e, own, out);
+                    }
+                }
+            }
+            Expression::BinaryExpression(be) => {
+                self.collect_captured_expr(&be.left, own, out);
+                self.collect_captured_expr(&be.right, own, out);
+            }
+            Expression::UnaryExpression(ue) => self.collect_captured_expr(&ue.argument, own, out),
+            Expression::LogicalExpression(le) => {
+                self.collect_captured_expr(&le.left, own, out);
+                self.collect_captured_expr(&le.right, own, out);
+            }
+            Expression::ConditionalExpression(ce) => {
+                self.collect_captured_expr(&ce.test, own, out);
+                self.collect_captured_expr(&ce.consequent, own, out);
+                self.collect_captured_expr(&ce.alternate, own, out);
+            }
+            Expression::SequenceExpression(se) => {
+                for e in &se.expressions {
+                    self.collect_captured_expr(e, own, out);
+                }
+            }
+            Expression::AssignmentExpression(ae) => self.collect_captured_expr(&ae.right, own, out),
+            Expression::ArrayExpression(ae) => {
+                for e in &ae.elements {
+                    if let Some(e) = e.as_expression() {
+                        self.collect_captured_expr(e, own, out);
+                    }
+                }
+            }
+            _ => {}
+        }
+    }
+
+    /// 分析子函数 body：引用父级绑定的名字 → upvalue_captures（enclosing_reg 由父 emit 完成后填充）。
+    /// 分析子函数 body：引用父级被捕获绑定的名字 → upvalue_captures。
+    /// cell_idx 直接取父 captured_bindings 映射（父 emit 前已确定，索引一致）；
+    /// enclosing_reg 由父 emit 完成后填充（assemble_ir）。
+    pub(crate) fn collect_upvalue_names(
+        &self, body_stmts: &[Statement], parent_captured: &BTreeMap<String, u8>, sub_own: &HashSet<String>,
+    ) -> Vec<UpvalueCapture> {
+        let parent_names: HashSet<String> = parent_captured.keys().cloned().collect();
+        let mut names = HashSet::new();
+        self.collect_capture_names_shadowed(body_stmts, &parent_names, sub_own, &mut names);
+        names
+            .into_iter()
+            .map(|name| {
+                let cell_idx = parent_captured.get(&name).copied().unwrap_or(0);
+                UpvalueCapture {
+                    name,
+                    enclosing_reg: 0, // assemble_ir 时从父符号表填充
+                    cell_idx,
+                }
+            })
+            .collect()
+    }
+}

crates/oxide_emit/src/emit.rs

@@ -0,0 +1,903 @@
+use std::collections::{BTreeMap, HashMap, HashSet};
+
+use oxide_bytecode::module::UpvalueCapture;
+use oxide_bytecode::opcode::OpCode;
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::{LabelId, Operand};
+use oxide_ir::IRFunction;
+
+use crate::emit_ctx::{LabelCtx, ScopeCtx};
+use crate::symbol_table::{Binding, ScopeKind, SymbolTable};
+
+pub use oxide_bytecode::module::Constant;
+pub use oxide_parser::VariableDeclarationKind;
+pub use oxide_parser::{AssignmentOperator, BinaryOperator, Expression, Statement, UnaryOperator};
+
+pub struct Emitter;
+
+pub fn is_int_literal(value: f64) -> bool {
+    value.fract() == 0.0 && value >= i32::MIN as f64 && value <= i32::MAX as f64
+}
+
+pub fn is_side_effect_free(expr: &Expression) -> bool {
+    let mut stack = vec![expr];
+    while let Some(expr) = stack.pop() {
+        match expr {
+            Expression::NumericLiteral(_)
+            | Expression::StringLiteral(_)
+            | Expression::BooleanLiteral(_)
+            | Expression::NullLiteral(_)
+            | Expression::Identifier(_)
+            | Expression::RegExpLiteral(_)
+            | Expression::ThisExpression(_) => {}
+            Expression::ParenthesizedExpression(p) => stack.push(&p.expression),
+            Expression::BinaryExpression(bin) => {
+                stack.push(&bin.left);
+                stack.push(&bin.right);
+            }
+            Expression::UnaryExpression(un) if !matches!(un.operator, UnaryOperator::Delete) => {
+                stack.push(&un.argument);
+            }
+            _ => return false,
+        }
+    }
+    true
+}
+
+const BUILTIN_GLOBALS: &[&str] = &[
+    "NaN",
+    "undefined",
+    "Infinity",
+    "globalThis",
+    "Object",
+    "Array",
+    "String",
+    "Number",
+    "Boolean",
+    "Function",
+    "Error",
+    "TypeError",
+    "ReferenceError",
+    "RangeError",
+    "SyntaxError",
+    "URIError",
+    "EvalError",
+    "Math",
+    "JSON",
+    "Promise",
+    "Date",
+    "Set",
+    "Map",
+    "RegExp",
+    "Symbol",
+    "parseInt",
+    "parseFloat",
+    "isNaN",
+    "isFinite",
+    "Proxy",
+    "WeakMap",
+    "WeakSet",
+    "WeakRef",
+    "FinalizationRegistry",
+    "Atomics",
+    "SharedArrayBuffer",
+    "ArrayBuffer",
+    "DataView",
+    "Iterator",
+    "BigInt",
+    "Int8Array",
+    "Uint8Array",
+    "Uint8ClampedArray",
+    "Int16Array",
+    "Uint16Array",
+    "Int32Array",
+    "Uint32Array",
+    "Float32Array",
+    "Float64Array",
+    "BigInt64Array",
+    "BigUint64Array",
+    "Reflect",
+    "escape",
+    "unescape",
+    "encodeURI",
+    "decodeURI",
+    "encodeURIComponent",
+    "decodeURIComponent",
+];
+
+pub(crate) struct FieldBuffer {
+    pub(crate) insts: Vec<Inst>,
+    pub(crate) labels: Vec<(LabelId, usize)>,
+}
+
+/// A labeled-statement scope active during emission. `break label` targets
+/// `break_label`; `continue label` targets `continue_label` (only set when the
+/// labeled statement directly wraps an iteration statement).
+#[derive(Debug, Clone)]
+pub struct LabelScope {
+    pub(crate) name: String,
+    pub(crate) break_label: LabelId,
+    pub(crate) continue_label: Option<LabelId>,
+}
+
+pub struct CompileCtx {
+    pub(crate) insts: Vec<Inst>,
+    pub(crate) constants: Vec<Constant>,
+    constant_map: HashMap<ConstantKey, u16>,
+    next_reg: u8,
+    pub(crate) max_regs: u8,
+    reserved_reg_start: u8,
+    pub(crate) labels: LabelCtx,
+    pub(crate) scopes: ScopeCtx,
+    pub(crate) nested: Vec<IRFunction>,
+    /// Register holding `this` in the enclosing function context.
+    /// Used by arrow functions to capture lexical `this`.
+    /// Initialized to 254 (conventional this register) at the top level.
+    pub(crate) enclosing_this_reg: u8,
+    pub(crate) in_derived_constructor: bool,
+    pub(crate) in_instance_method: bool,
+    pub(crate) in_static_method: bool,
+    pub(crate) static_block_this_reg: Option<u8>,
+    pub(crate) field_buffer: Option<FieldBuffer>,
+    pub(crate) current_upvalue_captures: Vec<UpvalueCapture>,
+    /// 本函数作用域声明的绑定名（参数 + 变量/函数声明，AST 收集，emit 前确定）。
+    pub(crate) own_bindings: HashSet<String>,
+    /// 本函数被嵌套函数捕获的绑定名 → cell_idx（名字排序分配，稳定跨 run）。
+    /// 捕获判断（MAKE_CELL / CELL_GET / CELL_SET）与子函数 upvalue cell_idx 统一查此映射，
+    /// 消除符号表时序依赖与 cell 索引错位。
+    pub(crate) captured_bindings: BTreeMap<String, u8>,
+    /// Set when alloc_reg() overflows into the reserved this/new.target range (≥254).
+    /// Checked after each emit phase to produce a compile error rather than silent corruption.
+    pub(crate) reg_overflow: bool,
+    pub(crate) const_overflow: bool,
+}
+
+#[derive(Clone, Copy)]
+pub enum FunctionBodyContext {
+    Ordinary,
+    Arrow,
+    ClassElement,
+}
+
+pub enum ParamSpec<'a> {
+    Identifier(String),
+    Pattern {
+        synthetic_name: String,
+        pattern: &'a oxide_parser::BindingPattern<'a>,
+    },
+}
+
+impl ParamSpec<'_> {
+    pub(crate) fn register_name(&self) -> &str {
+        match self {
+            Self::Identifier(name) => name,
+            Self::Pattern { synthetic_name, .. } => synthetic_name,
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+enum ConstantKey {
+    Number(u64),
+    Int(i32),
+    String(String),
+    Boolean(bool),
+    Null,
+    Undefined,
+}
+
+impl CompileCtx {
+    pub(crate) fn new() -> Self {
+        Self {
+            insts: Vec::new(),
+            constants: Vec::new(),
+            constant_map: HashMap::new(),
+            next_reg: 1,
+            max_regs: 1,
+            reserved_reg_start: 1,
+            labels: LabelCtx {
+                label_pos: Vec::new(),
+                loop_stack: Vec::new(),
+                switch_stack: Vec::new(),
+                label_scopes: Vec::new(),
+                pending_loop_labels: Vec::new(),
+                label_counter: 0,
+            },
+            scopes: ScopeCtx {
+                symbols: SymbolTable::new(),
+                builtin_reg_map: Vec::new(),
+                private_name_map: Vec::new(),
+                next_private_name_id: 1,
+            },
+            nested: Vec::new(),
+            enclosing_this_reg: 254, // conventional this register at top level
+            in_derived_constructor: false,
+            in_instance_method: false,
+            in_static_method: false,
+            static_block_this_reg: None,
+            field_buffer: None,
+            current_upvalue_captures: Vec::new(),
+            own_bindings: HashSet::new(),
+            captured_bindings: BTreeMap::new(),
+            reg_overflow: false,
+            const_overflow: false,
+        }
+    }
+
+    pub(crate) fn inst(&mut self, inst: Inst) {
+        self.insts.push(inst);
+    }
+
+    pub(crate) fn alloc_reg(&mut self) -> u8 {
+        let r = self.next_reg;
+        // Registers 254 (this) and 255 (new.target) are reserved by the VM.
+        // Allocating into them silently corrupts the call convention, turning
+        // method calls' `this` into garbage. Clamp to 253 and set a flag so
+        // the compiler can surface a proper error after the emit pass.
+        if r >= 254 {
+            self.reg_overflow = true;
+            return 253; // clamp to last safe register; emit continues but reg_overflow triggers error
+        }
+        self.next_reg = self.next_reg.wrapping_add(1);
+        if self.next_reg > self.max_regs {
+            self.max_regs = self.next_reg;
+        }
+        r
+    }
+
+    pub(crate) fn reset_regs(&mut self) {
+        self.next_reg = self.builtin_reg_floor().max(self.reserved_reg_start);
+        self.labels.label_counter = 0;
+    }
+
+    pub(crate) fn reg_checkpoint(&self) -> u8 {
+        self.next_reg
+    }
+
+    pub(crate) fn restore_reg_checkpoint(&mut self, checkpoint: u8) {
+        self.next_reg = checkpoint;
+    }
+
+    pub(crate) fn reserve_reg(&mut self, reg: u8) {
+        let next = reg.wrapping_add(1);
+        if self.next_reg <= reg {
+            self.next_reg = next;
+        }
+        if self.max_regs < next {
+            self.max_regs = next;
+        }
+    }
+
+    pub(crate) fn add_constant(&mut self, c: Constant) -> u16 {
+        if let Some(key) = ConstantKey::from_constant(&c) {
+            if let Some(&idx) = self.constant_map.get(&key) {
+                return idx;
+            }
+
+            if self.constants.len() >= u16::MAX as usize {
+                self.const_overflow = true;
+                return u16::MAX;
+            }
+            let idx = self.constants.len() as u16;
+            self.constants.push(c);
+            self.constant_map.insert(key, idx);
+            return idx;
+        }
+
+        let idx = self.constants.len();
+        if idx >= u16::MAX as usize {
+            self.const_overflow = true;
+            return u16::MAX;
+        }
+        self.constants.push(c);
+        idx as u16
+    }
+
+    pub(crate) fn push_scope(&mut self) {
+        self.scopes.symbols.push_scope();
+    }
+
+    pub(crate) fn pop_scope(&mut self) {
+        self.scopes.symbols.pop_scope();
+    }
+
+    pub(crate) fn declare(
+        &mut self, name: &str, reg: u8, kind: VariableDeclarationKind, is_const: bool,
+    ) -> Result<(), String> {
+        self.scopes.symbols.declare(name, reg, kind, is_const)
+    }
+
+    pub(crate) fn declare_initialized(
+        &mut self, name: &str, reg: u8, kind: VariableDeclarationKind, is_const: bool,
+    ) -> Result<(), String> {
+        self.scopes.symbols.declare_initialized(name, reg, kind, is_const)
+    }
+
+    pub(crate) fn push_scope_with_kind(&mut self, kind: ScopeKind) {
+        self.scopes.symbols.push_scope_with_kind(kind);
+    }
+
+    pub(crate) fn lookup(&self, name: &str) -> Result<u8, String> {
+        self.scopes.symbols.lookup(name)
+    }
+
+    pub(crate) fn lookup_or_builtin(&mut self, name: &str) -> Result<u8, String> {
+        match self.scopes.symbols.lookup(name) {
+            Ok(reg) => Ok(reg),
+            Err(err) if Self::is_known_builtin(name) && err.contains("is not defined") => {
+                let reg = self.alloc_reg();
+                self.scopes.symbols.pre_register_global(name, reg);
+                self.scopes.builtin_reg_map.push((name.to_string(), reg));
+                Ok(reg)
+            }
+            Err(err) => Err(err),
+        }
+    }
+
+    pub(crate) fn lookup_or_global(&mut self, name: &str) -> u8 {
+        if let Some(reg) = self.scopes.symbols.lookup_any(name) {
+            return reg;
+        }
+        let reg = self.alloc_reg();
+        self.scopes.symbols.lookup_or_global(name, reg)
+    }
+
+    pub(crate) fn lookup_const_flag(&self, name: &str) -> bool {
+        self.scopes.symbols.lookup_is_const(name)
+    }
+
+    pub(crate) fn init_var(&mut self, name: &str) {
+        self.scopes.symbols.init_var(name);
+    }
+
+    pub(crate) fn next_label_id(&mut self) -> u32 {
+        let id = self.labels.label_counter;
+        self.labels.label_counter += 1;
+        id
+    }
+
+    pub(crate) fn push_loop(&mut self, break_label: LabelId, continue_label: LabelId) {
+        self.labels.loop_stack.push((break_label, continue_label));
+    }
+
+    pub(crate) fn pop_loop(&mut self) {
+        self.labels.loop_stack.pop();
+    }
+
+    pub(crate) fn current_loop(&self) -> Option<&(LabelId, LabelId)> {
+        self.labels.loop_stack.last()
+    }
+
+    pub(crate) fn push_switch(&mut self, break_label: LabelId) {
+        self.labels.switch_stack.push(break_label);
+    }
+
+    pub(crate) fn pop_switch(&mut self) {
+        self.labels.switch_stack.pop();
+    }
+
+    pub(crate) fn current_switch(&self) -> Option<&LabelId> {
+        self.labels.switch_stack.last()
+    }
+
+    pub(crate) fn push_label_scope(
+        &mut self, name: &str, break_label: LabelId, continue_label: Option<LabelId>,
+    ) -> Result<(), String> {
+        if self.labels.label_scopes.iter().any(|s| s.name == name) {
+            return Err(format!("SyntaxError: Label '{name}' has already been declared"));
+        }
+        self.labels.label_scopes.push(LabelScope {
+            name: name.to_string(),
+            break_label,
+            continue_label,
+        });
+        Ok(())
+    }
+
+    pub(crate) fn pop_label_scope(&mut self) {
+        self.labels.label_scopes.pop();
+    }
+
+    pub(crate) fn find_label(&self, name: &str) -> Option<&LabelScope> {
+        self.labels.label_scopes.iter().rev().find(|s| s.name == name)
+    }
+
+    /// Queue a label name to be bound to the continue target of the next loop
+    /// emitted as the labeled statement's body. Rejects duplicates in the active
+    /// or pending sets.
+    pub(crate) fn queue_loop_label(&mut self, name: &str) -> Result<(), String> {
+        if self.labels.label_scopes.iter().any(|s| s.name == name)
+            || self.labels.pending_loop_labels.iter().any(|n| n == name)
+        {
+            return Err(format!("SyntaxError: Label '{name}' has already been declared"));
+        }
+        self.labels.pending_loop_labels.push(name.to_string());
+        Ok(())
+    }
+
+    /// Drain queued loop labels into active scopes bound to this loop's break and
+    /// continue targets. Returns how many scopes were pushed (to pop after).
+    pub(crate) fn take_pending_loop_labels(&mut self, break_label: LabelId, continue_label: LabelId) -> usize {
+        let names = std::mem::take(&mut self.labels.pending_loop_labels);
+        let count = names.len();
+        for name in names {
+            self.labels.label_scopes.push(LabelScope {
+                name,
+                break_label,
+                continue_label: Some(continue_label),
+            });
+        }
+        count
+    }
+
+    pub(crate) fn pop_label_scopes(&mut self, n: usize) {
+        for _ in 0..n {
+            self.labels.label_scopes.pop();
+        }
+    }
+
+    pub(crate) fn is_builtin(&self, name: &str) -> bool {
+        self.scopes.builtin_reg_map.iter().any(|(n, _)| n == name)
+    }
+
+    pub(crate) fn is_known_builtin(name: &str) -> bool {
+        BUILTIN_GLOBALS.contains(&name)
+    }
+
+    fn builtin_reg_floor(&self) -> u8 {
+        self.scopes
+            .builtin_reg_map
+            .iter()
+            .map(|(_, reg)| reg.saturating_add(1))
+            .max()
+            .unwrap_or(0)
+    }
+
+    pub(crate) fn pre_register_builtins(&mut self) {
+        // Builtin globals are resolved lazily by lookup_or_builtin(). Keeping this
+        // hook preserves the compile pipeline without reserving ~60 registers in
+        // every module.
+    }
+
+    /// 组装 IRFunction（两出口共用），take 走编译产物状态。
+    /// `parent_ctx` 用于补全 upvalue_captures 的 enclosing_reg（父符号表在父 emit 完成后完整）。
+    fn assemble_ir(&mut self, param_layout: oxide_ir::ParamLayout, parent_ctx: Option<&CompileCtx>) -> IRFunction {
+        let upvalue_captures = self
+            .current_upvalue_captures
+            .iter()
+            .map(|u| {
+                let enclosing_reg = parent_ctx
+                    .and_then(|p| p.scopes.symbols.lookup_any(u.name.as_str()))
+                    .unwrap_or(0);
+                UpvalueCapture {
+                    name: u.name.clone(),
+                    enclosing_reg,
+                    cell_idx: u.cell_idx,
+                }
+            })
+            .collect();
+        IRFunction {
+            insts: std::mem::take(&mut self.insts),
+            label_pos: std::mem::take(&mut self.labels.label_pos),
+            label_count: self.labels.label_counter,
+            constants: std::mem::take(&mut self.constants),
+            param_layout,
+            builtin_reg_map: std::mem::take(&mut self.scopes.builtin_reg_map),
+            upvalue_captures,
+            cells_needed: self.captured_bindings.len() as u8,
+            n_registers: self.max_regs,
+            is_arrow: false,
+            is_class_constructor: false,
+            is_derived_constructor: false,
+            needs_home_object: false,
+            captured_this_const_idx: 0,
+            function_name: None,
+            reg_overflow: self.reg_overflow,
+            const_overflow: self.const_overflow,
+            nested: std::mem::take(&mut self.nested),
+        }
+    }
+}
+
+impl ConstantKey {
+    fn from_constant(value: &Constant) -> Option<Self> {
+        match value {
+            Constant::Number(v) => Some(Self::Number(v.to_bits())),
+            Constant::Int(v) => Some(Self::Int(*v)),
+            Constant::String(v) => Some(Self::String(v.clone())),
+            Constant::Boolean(v) => Some(Self::Boolean(*v)),
+            Constant::Null => Some(Self::Null),
+            Constant::Undefined => Some(Self::Undefined),
+        }
+    }
+}
+
+impl Emitter {
+    pub fn new() -> Self {
+        Self
+    }
+
+    // ── 闭包捕获分析（AST 级，时序无关）──
+
+    /// 收集函数参数的绑定名（BindingIdentifier 形态）。
+
+
+    pub(crate) fn extract_function_parts<'a>(
+        &self, function: &'a oxide_parser::Function<'a>,
+    ) -> Result<(Vec<ParamSpec<'a>>, &'a [Statement<'a>]), String> {
+        let mut param_specs = Vec::new();
+        for (idx, param) in function.params.items.iter().enumerate() {
+            match &param.pattern {
+                oxide_parser::BindingPattern::BindingIdentifier(bi) => {
+                    param_specs.push(ParamSpec::Identifier(bi.name.to_string()));
+                }
+                pattern => {
+                    param_specs.push(ParamSpec::Pattern {
+                        synthetic_name: format!("@@param_{idx}"),
+                        pattern,
+                    });
+                }
+            }
+        }
+        let body_stmts: &[Statement] = if let Some(body) = &function.body { &body.statements } else { &[] };
+        Ok((param_specs, body_stmts))
+    }
+
+    /// Compile a function body (used for FD, FE, and arrow functions).
+    /// This performs both counting and emitting in one pass.
+    /// When `is_expression_body` is true (arrow function with expression body),
+    /// the last expression's value is returned instead of undefined.
+    /// `is_arrow` controls whether super flags are inherited from the parent scope
+    /// (true for arrow functions, which have lexical super) or reset to false
+    /// (false for regular functions, which create a new super scope).
+    pub(crate) fn compile_function_body<'a>(
+        &self, param_specs: &[ParamSpec<'a>], body_stmts: &[Statement<'a>], parent_ctx: &CompileCtx,
+        is_expression_body: bool, is_arrow: bool,
+    ) -> Result<IRFunction, String> {
+        let body_context = if is_arrow {
+            FunctionBodyContext::Arrow
+        } else {
+            FunctionBodyContext::Ordinary
+        };
+        self.compile_function_body_with_bindings(
+            param_specs,
+            body_stmts,
+            parent_ctx,
+            is_expression_body,
+            &[],
+            body_context,
+        )
+    }
+
+    pub(crate) fn compile_function_body_with_bindings<'a>(
+        &self, param_specs: &[ParamSpec<'a>], body_stmts: &[Statement<'a>], parent_ctx: &CompileCtx,
+        is_expression_body: bool, extra_bindings: &[(&str, u8)], body_context: FunctionBodyContext,
+    ) -> Result<IRFunction, String> {
+        self.compile_function_body_with_field_hooks(
+            param_specs,
+            body_stmts,
+            parent_ctx,
+            is_expression_body,
+            extra_bindings,
+            body_context,
+            None::<fn(&Emitter, &mut CompileCtx) -> Result<(), String>>,
+            false,
+        )
+    }
+
+
+    /// Pre-register all builtin identifiers referenced anywhere in this body
+    /// (expressions, member objects, call args, class fields, etc.) so their
+    /// register slots are reserved *before* any temporary register is emitted.
+    ///
+    /// Without this, single-pass emission lazily allocates builtin slots via
+    /// `lookup_or_builtin` at first use, which can collide with a temporary
+    /// register already reused by `restore_reg_checkpoint`. Pre-scanning moves
+    /// builtin slot allocation ahead of the temporary register pool.
+    #[allow(clippy::too_many_arguments)]
+    pub(crate) fn compile_function_body_with_field_hooks<'a, E>(
+        &self, param_specs: &[ParamSpec<'a>], body_stmts: &[Statement<'a>], parent_ctx: &CompileCtx,
+        is_expression_body: bool, extra_bindings: &[(&str, u8)], body_context: FunctionBodyContext,
+        mut emit_fields: Option<E>, fields_after_super: bool,
+    ) -> Result<IRFunction, String>
+    where
+        E: FnMut(&Emitter, &mut CompileCtx) -> Result<(), String>,
+    {
+        let mut ctx = CompileCtx::new();
+
+        // Inherit parent's builtin_reg_map so builtin identifiers (Math, Object, etc.)
+        // resolve to the correct pre-allocated registers in the sub-module's register file.
+        ctx.scopes.builtin_reg_map = parent_ctx.scopes.builtin_reg_map.clone();
+        ctx.scopes.private_name_map = parent_ctx.scopes.private_name_map.clone();
+        ctx.scopes.next_private_name_id = parent_ctx.scopes.next_private_name_id;
+
+        // Propagate enclosing_this_reg so nested arrow functions capture the correct `this`.
+        ctx.enclosing_this_reg = parent_ctx.enclosing_this_reg;
+        // Arrow functions inherit lexical super. Class method bodies also need the
+        // class-provided super context for their top-level body compilation.
+        if matches!(body_context, FunctionBodyContext::Arrow | FunctionBodyContext::ClassElement) {
+            ctx.in_derived_constructor = parent_ctx.in_derived_constructor;
+            ctx.in_instance_method = parent_ctx.in_instance_method;
+            ctx.in_static_method = parent_ctx.in_static_method;
+        } else {
+            ctx.in_derived_constructor = false;
+            ctx.in_instance_method = false;
+            ctx.in_static_method = false;
+        }
+
+        // Inherit parent's global scope entries so previously-declared function names
+        // are visible from within the body.
+        let mut inherited_reg_start = 1u8.max(ctx.builtin_reg_floor());
+        for (name, binding) in &parent_ctx.scopes.symbols.scopes[0].bindings {
+            ctx.scopes.symbols.scopes[0].bindings.insert(
+                name.clone(),
+                Binding {
+                    reg: binding.reg,
+                    initialized: binding.initialized,
+                    is_const: binding.is_const,
+                },
+            );
+            inherited_reg_start = inherited_reg_start.max(binding.reg.saturating_add(1));
+        }
+        for (name, reg) in extra_bindings {
+            ctx.scopes.symbols.scopes[0].bindings.insert(
+                (*name).to_string(),
+                Binding {
+                    reg: *reg,
+                    initialized: true,
+                    is_const: true,
+                },
+            );
+            inherited_reg_start = inherited_reg_start.max(reg.saturating_add(1));
+        }
+        ctx.reserved_reg_start = inherited_reg_start.max(1);
+
+        // Align next_reg with builtin count so both count and emit passes start at the
+        // same register offset (params go after builtin slots).
+        ctx.reset_regs();
+
+        let param_base = self.emit_params_prologue(param_specs, body_stmts, parent_ctx, &mut ctx, body_context)?;
+
+        self.predeclare_function_declarations(body_stmts, &mut ctx);
+
+        // Pre-register builtin identifier references before emitting any temporary
+        // register, so builtin slots never collide with reused temporaries.
+        self.pre_register_builtin_references(body_stmts, &mut ctx);
+
+        // Pre-declare `var` names so hoisted function declarations (emitted in the
+        // first sub-pass below) can resolve the outer vars they close over.
+        self.predeclare_var_declarations(body_stmts, &mut ctx);
+
+        if let Some(emit) = emit_fields.as_mut() {
+            if fields_after_super {
+                let mut parent_insts = Vec::new();
+                let mut parent_label_pos = Vec::new();
+                std::mem::swap(&mut ctx.insts, &mut parent_insts);
+                std::mem::swap(&mut ctx.labels.label_pos, &mut parent_label_pos);
+                emit(self, &mut ctx)?;
+                let field_buffer = FieldBuffer {
+                    insts: std::mem::take(&mut ctx.insts),
+                    labels: std::mem::take(&mut ctx.labels.label_pos)
+                        .into_iter()
+                        .enumerate()
+                        .filter_map(|(id, pos)| pos.map(|p| (id as LabelId, p)))
+                        .collect(),
+                };
+                ctx.insts = parent_insts;
+                ctx.labels.label_pos = parent_label_pos;
+                ctx.field_buffer = Some(field_buffer);
+            } else {
+                emit(self, &mut ctx)?;
+            }
+        }
+
+        // Emit body statements（先函数声明 hoisting，再其余）。
+        let last_result_reg = self.emit_body_stmts(body_stmts, &mut ctx)?;
+
+        // Emit implicit RETURN: expression body returns the last expression,
+        // statement body returns undefined.
+        if is_expression_body {
+            if let Some(reg) = last_result_reg {
+                ctx.inst(Inst::new(OpCode::RETURN, Operand::Reg(reg as u32), Operand::None, Operand::None));
+            } else {
+                let undef_idx = ctx.add_constant(Constant::Undefined);
+                let undef_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(undef_reg as u32), undef_idx));
+                ctx.inst(Inst::new(OpCode::RETURN, Operand::Reg(undef_reg as u32), Operand::None, Operand::None));
+            }
+        } else {
+            let undef_idx = ctx.add_constant(Constant::Undefined);
+            let undef_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(undef_reg as u32), undef_idx));
+            ctx.inst(Inst::new(OpCode::RETURN, Operand::Reg(undef_reg as u32), Operand::None, Operand::None));
+        }
+
+        let ir = ctx.assemble_ir(
+            oxide_ir::ParamLayout {
+                base: param_base as u32,
+                count: param_specs.len() as u32,
+            },
+            Some(parent_ctx),
+        );
+        Ok(ir)
+    }
+
+    /// 参数 prologue：函数作用域 + 参数声明/解构 + 闭包捕获与 upvalue 分析。返回 param_base。
+    fn emit_params_prologue<'a>(
+        &self, param_specs: &[ParamSpec<'a>], body_stmts: &[Statement<'a>], parent_ctx: &CompileCtx,
+        ctx: &mut CompileCtx, body_context: FunctionBodyContext,
+    ) -> Result<u8, String> {
+        ctx.push_scope_with_kind(ScopeKind::FunctionScope);
+        let param_base = ctx.next_reg;
+
+        // Emit parameters and destructuring prologue.
+        for spec in param_specs {
+            let name = spec.register_name();
+            let reg = ctx.alloc_reg();
+            ctx.declare_initialized(name, reg, VariableDeclarationKind::Var, false)?;
+        }
+
+        for spec in param_specs {
+            if let ParamSpec::Pattern { synthetic_name, pattern } = spec {
+                let src_reg = ctx.lookup(synthetic_name)?;
+                self.emit_binding_pattern(pattern, src_reg, VariableDeclarationKind::Var, false, ctx)?;
+            }
+        }
+
+        // 闭包捕获分析（AST 级，emit 前确定，时序无关）
+        let param_names: Vec<&str> = param_specs.iter().map(|s| s.register_name()).collect();
+        ctx.own_bindings = self.collect_own_binding_names(&param_names, body_stmts);
+        ctx.captured_bindings = self.collect_captured_bindings(body_stmts, &ctx.own_bindings);
+
+        // Free variable analysis for upvalue capture (Ordinary + Arrow functions only)
+        if matches!(body_context, FunctionBodyContext::Ordinary | FunctionBodyContext::Arrow) {
+            ctx.current_upvalue_captures =
+                self.collect_upvalue_names(body_stmts, &parent_ctx.captured_bindings, &ctx.own_bindings);
+        }
+
+        Ok(param_base)
+    }
+
+    /// 双 sub-pass emit body：先函数声明（hoisting），再其余语句。返回最后结果寄存器。
+    fn emit_body_stmts(&self, body_stmts: &[Statement], ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let mut last_result_reg = None;
+        for stmt in body_stmts {
+            if matches!(stmt, Statement::FunctionDeclaration(_)) {
+                if let Some(reg) = self.emit_statement(stmt, ctx)? {
+                    last_result_reg = Some(reg);
+                }
+            }
+        }
+        for stmt in body_stmts {
+            if matches!(stmt, Statement::FunctionDeclaration(_)) {
+                continue;
+            }
+            if let Some(reg) = self.emit_statement(stmt, ctx)? {
+                last_result_reg = Some(reg);
+            }
+        }
+        Ok(last_result_reg)
+    }
+
+    pub(crate) fn emit_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        match stmt {
+            Statement::ExpressionStatement(_) | Statement::ReturnStatement(_) | Statement::EmptyStatement(_) => {
+                self.emit_basic_domain(stmt, ctx)
+            }
+            Statement::BlockStatement(_) => self.emit_block_domain(stmt, ctx),
+            Statement::VariableDeclaration(_) | Statement::FunctionDeclaration(_) | Statement::ClassDeclaration(_) => {
+                self.emit_declaration_domain(stmt, ctx)
+            }
+            Statement::IfStatement(_) => self.emit_control_domain(stmt, ctx),
+            Statement::WhileStatement(_)
+            | Statement::DoWhileStatement(_)
+            | Statement::ForStatement(_)
+            | Statement::ForInStatement(_)
+            | Statement::ForOfStatement(_) => self.emit_iteration_domain(stmt, ctx),
+            Statement::SwitchStatement(_) => self.emit_switch_domain(stmt, ctx),
+            Statement::ThrowStatement(_) | Statement::TryStatement(_) => self.emit_exception_domain(stmt, ctx),
+            Statement::BreakStatement(b) => self.emit_break_statement(b, ctx),
+            Statement::ContinueStatement(c) => self.emit_continue_statement(c, ctx),
+            Statement::LabeledStatement(ls) => self.emit_labeled_statement(ls, ctx),
+            _ => Ok(None),
+        }
+    }
+
+    pub(crate) fn emit_expression(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match expr {
+            Expression::NumericLiteral(_)
+            | Expression::StringLiteral(_)
+            | Expression::BooleanLiteral(_)
+            | Expression::NullLiteral(_)
+            | Expression::RegExpLiteral(_) => self.emit_literal(expr, ctx),
+            Expression::BinaryExpression(_)
+            | Expression::PrivateInExpression(_)
+            | Expression::UnaryExpression(_)
+            | Expression::ConditionalExpression(_)
+            | Expression::LogicalExpression(_)
+            | Expression::UpdateExpression(_) => self.emit_operator(expr, ctx),
+            Expression::StaticMemberExpression(_)
+            | Expression::ComputedMemberExpression(_)
+            | Expression::PrivateFieldExpression(_)
+            | Expression::ChainExpression(_) => self.emit_member_domain(expr, ctx),
+            Expression::ObjectExpression(_) | Expression::ArrayExpression(_) => self.emit_object_domain(expr, ctx),
+            Expression::AssignmentExpression(assign) => self.emit_assignment_expression(assign, ctx),
+            Expression::TemplateLiteral(_) | Expression::TaggedTemplateExpression(_) => {
+                self.emit_template_domain(expr, ctx)
+            }
+            Expression::ArrowFunctionExpression(_)
+            | Expression::FunctionExpression(_)
+            | Expression::ClassExpression(_)
+            | Expression::NewExpression(_) => self.emit_function_domain(expr, ctx),
+            Expression::Identifier(ident) => self.emit_identifier_expression(ident, ctx),
+            Expression::CallExpression(_) => self.emit_call_domain(expr, ctx),
+            Expression::ThisExpression(_) => self.emit_this_expression(ctx),
+            Expression::SequenceExpression(seq) => self.emit_sequence_expression(seq, ctx),
+            Expression::ParenthesizedExpression(p) => self.emit_parenthesized_expression(p, ctx),
+            _ => self.emit_unsupported_expression(expr, ctx),
+        }
+    }
+
+    /// Emit a full program into an IRFunction (top-level module body).
+    /// Split from the original `Compiler::compile`: this is the emit half;
+    /// oxide_compiler::Compiler::compile calls this then `oxide_ir::lower::lower`.
+    pub fn emit_program(&self, program: &oxide_parser::Program) -> Result<IRFunction, String> {
+        let mut ctx = CompileCtx::new();
+        ctx.pre_register_builtins();
+        self.predeclare_function_declarations(&program.body, &mut ctx);
+
+        // Pre-register builtin identifier references before any temporary register
+        // is emitted, keeping builtin slots clear of the temporary register pool.
+        self.pre_register_builtin_references(&program.body, &mut ctx);
+
+        // Pre-declare top-level `var` names so hoisted function declarations
+        // (emitted in the first sub-pass below) can resolve the outer vars.
+        self.predeclare_var_declarations(&program.body, &mut ctx);
+
+        // 闭包捕获分析（AST 级，emit 前确定）
+        ctx.own_bindings = self.collect_own_binding_names(&[], &program.body);
+        ctx.captured_bindings = self.collect_captured_bindings(&program.body, &ctx.own_bindings);
+
+        // First sub-pass: emit FunctionDeclarations (hoisting)
+        // This ensures function objects are available before any code runs.
+        for stmt in &program.body {
+            if matches!(stmt, Statement::FunctionDeclaration(_)) {
+                self.emit_statement(stmt, &mut ctx)?;
+            }
+        }
+
+        // Second sub-pass: emit all other statements
+        let mut last_result: Option<u8> = None;
+        for stmt in &program.body {
+            if matches!(stmt, Statement::FunctionDeclaration(_)) {
+                continue; // Already emitted above
+            }
+            match self.emit_statement(stmt, &mut ctx)? {
+                Some(r) => last_result = Some(r),
+                None => last_result = None,
+            }
+        }
+        if let Some(r) = last_result {
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::None, Operand::Reg(r as u32), Operand::None));
+        } else {
+            let undef_idx = ctx.add_constant(Constant::Undefined);
+            ctx.inst(Inst::load_const(Operand::None, undef_idx));
+        }
+        ctx.inst(Inst::new(OpCode::HALT, Operand::None, Operand::None, Operand::None));
+
+        let ir = ctx.assemble_ir(
+            oxide_ir::ParamLayout {
+                base: ctx.scopes.builtin_reg_map.len() as u32,
+                count: 0,
+            },
+            None,
+        );
+        Ok(ir)
+    }
+}
+
+impl Default for Emitter {
+    fn default() -> Self {
+        Self::new()
+    }
+}

crates/oxide_emit/src/emit_ctx.rs

@@ -0,0 +1,47 @@
+//! Grouped `CompileCtx` sub-contexts.
+//!
+//! Splits the compiler's central `CompileCtx` so syntax-domain workers borrow
+//! only the slice they need: `LabelCtx` for jump-target resolution, `ScopeCtx`
+//! for identifier binding. `PatternCtx` is reserved for destructuring work.
+//! Execution-stream fields (insts, registers, pc, …) stay flat on
+//! `CompileCtx`.
+
+use crate::symbol_table::SymbolTable;
+use crate::LabelScope;
+use oxide_ir::operand::LabelId;
+
+/// Jump-target / labeled-statement resolution state.
+pub(crate) struct LabelCtx {
+    /// label id → 指令下标。id 连续递增，Vec 索引即 id；写入前须扩容。
+    pub(crate) label_pos: Vec<Option<usize>>,
+    pub(crate) loop_stack: Vec<(LabelId, LabelId)>,
+    pub(crate) switch_stack: Vec<LabelId>,
+    /// Active labeled-statement scopes (resolves `break label` / `continue label`).
+    pub(crate) label_scopes: Vec<LabelScope>,
+    /// Label names awaiting binding to the next emitted loop's continue target.
+    pub(crate) pending_loop_labels: Vec<String>,
+    pub(crate) label_counter: u32,
+}
+
+impl LabelCtx {
+    /// 按 id 扩容后写入 label 定义位置。
+    pub(crate) fn set_label_pos(&mut self, id: LabelId, pos: usize) {
+        if id as usize >= self.label_pos.len() {
+            self.label_pos.resize(id as usize + 1, None);
+        }
+        self.label_pos[id as usize] = Some(pos);
+    }
+}
+
+/// Identifier-binding state: symbols, builtin registers, private names.
+pub(crate) struct ScopeCtx {
+    pub(crate) symbols: SymbolTable,
+    pub(crate) builtin_reg_map: Vec<(String, u8)>,
+    pub(crate) private_name_map: Vec<(String, u32)>,
+    pub(crate) next_private_name_id: u32,
+}
+
+/// Reserved for destructuring-pattern state (Phase 15). Intentionally empty
+/// today; named so future pattern work has a home without touching `ScopeCtx`.
+#[allow(dead_code)]
+pub(crate) struct PatternCtx;

crates/oxide_emit/src/expr/assignment.rs

@@ -0,0 +1,174 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::AssignmentOperator;
+
+impl Emitter {
+    pub(crate) fn emit_assignment_expression(
+        &self, assign: &oxide_parser::AssignmentExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        if let oxide_parser::AssignmentTarget::StaticMemberExpression(member) = &assign.left {
+            if let Some(logical_op) = assign.operator.to_logical_operator() {
+                let store_label = ctx.next_label_id();
+                let end_label = ctx.next_label_id();
+                let obj_reg = self.emit_expression(&member.object, ctx)?;
+                let prop_name = member.property.name.as_str();
+                let idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+                let key_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), idx));
+                let result_reg = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(obj_reg as u32), Operand::None));
+                ctx.inst(Inst::ic_get(Operand::Reg(result_reg as u32), Operand::Reg(key_reg as u32)));
+                self.emit_logical_assign_test(logical_op, result_reg, store_label, end_label, ctx)?;
+                ctx.labels.set_label_pos(store_label, ctx.insts.len());
+                let val_reg = self.emit_expression(&assign.right, ctx)?;
+                ctx.inst(Inst::ic_set(Operand::Reg(obj_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(key_reg as u32)));
+                ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(val_reg as u32), Operand::None));
+                ctx.labels.set_label_pos(end_label, ctx.insts.len());
+                return Ok(result_reg);
+            }
+            let obj_reg = self.emit_expression(&member.object, ctx)?;
+            let val_reg = self.emit_expression(&assign.right, ctx)?;
+            let prop_name = member.property.name.as_str();
+            let idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+            let key_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), idx));
+            if assign.operator != AssignmentOperator::Assign {
+                let obj = Operand::Reg(obj_reg as u32);
+                let val = Operand::Reg(val_reg as u32);
+                let key = Operand::Reg(key_reg as u32);
+                match assign.operator {
+                    AssignmentOperator::Addition => ctx.inst(Inst::compound_member_add(obj, val, key)),
+                    AssignmentOperator::Subtraction => ctx.inst(Inst::compound_member_sub(obj, val, key)),
+                    AssignmentOperator::Multiplication => ctx.inst(Inst::compound_member_mul(obj, val, key)),
+                    AssignmentOperator::Division => ctx.inst(Inst::compound_member_div(obj, val, key)),
+                    AssignmentOperator::Remainder => ctx.inst(Inst::compound_member_mod(obj, val, key)),
+                    AssignmentOperator::Exponential => ctx.inst(Inst::compound_member_exp(obj, val, key)),
+                    _ => return Err(format!("compound assignment operator {:?} not supported", assign.operator)),
+                }
+                Ok(val_reg)
+            } else {
+                ctx.inst(Inst::ic_set(Operand::Reg(obj_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(key_reg as u32)));
+                Ok(val_reg)
+            }
+        } else if let oxide_parser::AssignmentTarget::ComputedMemberExpression(member) = &assign.left {
+            if let Some(logical_op) = assign.operator.to_logical_operator() {
+                let store_label = ctx.next_label_id();
+                let end_label = ctx.next_label_id();
+                let obj_reg = self.emit_expression(&member.object, ctx)?;
+                let key_reg = self.emit_expression(&member.expression, ctx)?;
+                let result_reg = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::GET_PROP_DYNAMIC, Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32), Operand::Reg(result_reg as u32)));
+                self.emit_logical_assign_test(logical_op, result_reg, store_label, end_label, ctx)?;
+                ctx.labels.set_label_pos(store_label, ctx.insts.len());
+                let val_reg = self.emit_expression(&assign.right, ctx)?;
+                ctx.inst(Inst::new(OpCode::SET_PROP_DYNAMIC, Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32), Operand::Reg(val_reg as u32)));
+                ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(val_reg as u32), Operand::None));
+                ctx.labels.set_label_pos(end_label, ctx.insts.len());
+                return Ok(result_reg);
+            }
+            let obj_reg = self.emit_expression(&member.object, ctx)?;
+            let key_reg = self.emit_expression(&member.expression, ctx)?;
+            let val_reg = self.emit_expression(&assign.right, ctx)?;
+            ctx.inst(Inst::new(OpCode::SET_PROP_DYNAMIC, Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32), Operand::Reg(val_reg as u32)));
+            Ok(val_reg)
+        } else if let oxide_parser::AssignmentTarget::PrivateFieldExpression(member) = &assign.left {
+            if assign.operator != AssignmentOperator::Assign {
+                return Err("compound assignment to private fields not supported".into());
+            }
+            let obj_reg = self.emit_expression(&member.object, ctx)?;
+            let val_reg = self.emit_expression(&assign.right, ctx)?;
+            let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
+            ctx.inst(Inst::new(OpCode::SET_PRIVATE, Operand::Reg(obj_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(key_reg as u32)));
+            Ok(val_reg)
+        } else if let oxide_parser::AssignmentTarget::AssignmentTargetIdentifier(id_ref) = &assign.left {
+            if assign.operator != AssignmentOperator::Assign {
+                if let Some(logical_op) = assign.operator.to_logical_operator() {
+                    let store_label = ctx.next_label_id();
+                    let end_label = ctx.next_label_id();
+                    let name = id_ref.name.as_str();
+                    let var_reg = ctx.lookup_or_global(name);
+                    let result_reg = ctx.alloc_reg();
+                    ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(var_reg as u32), Operand::None));
+                    self.emit_logical_assign_test(logical_op, result_reg, store_label, end_label, ctx)?;
+                    ctx.labels.set_label_pos(store_label, ctx.insts.len());
+                    let val_reg = self.emit_expression(&assign.right, ctx)?;
+                    let is_const = ctx.lookup_const_flag(name);
+                    let const_flag = if is_const { 1 } else { 0 };
+                    ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(var_reg as u32), Operand::Reg(val_reg as u32), Operand::Imm(const_flag)));
+                    ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(val_reg as u32), Operand::None));
+                    ctx.labels.set_label_pos(end_label, ctx.insts.len());
+                    Ok(result_reg)
+                } else if assign.operator == AssignmentOperator::Addition
+                    || assign.operator == AssignmentOperator::Subtraction
+                    || assign.operator == AssignmentOperator::Multiplication
+                    || assign.operator == AssignmentOperator::Division
+                    || assign.operator == AssignmentOperator::Remainder
+                    || assign.operator == AssignmentOperator::Exponential
+                    || assign.operator == AssignmentOperator::BitwiseAnd
+                    || assign.operator == AssignmentOperator::BitwiseOR
+                    || assign.operator == AssignmentOperator::BitwiseXOR
+                    || assign.operator == AssignmentOperator::ShiftLeft
+                    || assign.operator == AssignmentOperator::ShiftRight
+                    || assign.operator == AssignmentOperator::ShiftRightZeroFill
+                {
+                    let rhs = self.emit_expression(&assign.right, ctx)?;
+                    let name = id_ref.name.as_str();
+                    let var_reg = ctx.lookup_or_global(name);
+                    let op = match assign.operator {
+                        AssignmentOperator::Addition => OpCode::COMPOUND_ADD,
+                        AssignmentOperator::Subtraction => OpCode::COMPOUND_SUB,
+                        AssignmentOperator::Multiplication => OpCode::COMPOUND_MUL,
+                        AssignmentOperator::Division => OpCode::COMPOUND_DIV,
+                        AssignmentOperator::Remainder => OpCode::COMPOUND_MOD,
+                        AssignmentOperator::Exponential => OpCode::COMPOUND_EXP,
+                        AssignmentOperator::BitwiseAnd => OpCode::COMPOUND_AND,
+                        AssignmentOperator::BitwiseOR => OpCode::COMPOUND_OR,
+                        AssignmentOperator::BitwiseXOR => OpCode::COMPOUND_XOR,
+                        AssignmentOperator::ShiftLeft => OpCode::COMPOUND_SHL,
+                        AssignmentOperator::ShiftRight => OpCode::COMPOUND_SHR,
+                        AssignmentOperator::ShiftRightZeroFill => OpCode::COMPOUND_USHR,
+                        _ => return Err(format!("compound assignment operator {:?} not supported", assign.operator)),
+                    };
+                    ctx.inst(Inst::new(op, Operand::Reg(var_reg as u32), Operand::Reg(rhs as u32), Operand::None));
+                    Ok(var_reg)
+                } else {
+                    Err(format!("compound assignment operator {:?} not supported", assign.operator))
+                }
+            } else {
+                let val_reg = self.emit_expression(&assign.right, ctx)?;
+                let name = id_ref.name.as_str();
+                // Check if target is an upvalue reference
+                if let Some(uv_idx) = ctx.current_upvalue_captures.iter().position(|u| u.name == name) {
+                    ctx.inst(Inst::new(OpCode::STORE_UPVALUE, Operand::None, Operand::Reg(val_reg as u32), Operand::Imm(uv_idx as u16)));
+                    return Ok(val_reg);
+                }
+                // Check if target is a captured cell
+                if let Some(&cell_idx) = ctx.captured_bindings.get(name) {
+                    ctx.inst(Inst::new(OpCode::CELL_SET, Operand::None, Operand::Reg(val_reg as u32), Operand::Imm(cell_idx as u16)));
+                    return Ok(val_reg);
+                }
+                let var_reg = ctx.lookup_or_global(name);
+                let is_const = ctx.lookup_const_flag(name);
+                let const_flag = if is_const { 1 } else { 0 };
+                ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(var_reg as u32), Operand::Reg(val_reg as u32), Operand::Imm(const_flag)));
+                Ok(val_reg)
+            }
+        } else if matches!(
+            &assign.left,
+            oxide_parser::AssignmentTarget::ArrayAssignmentTarget(_)
+                | oxide_parser::AssignmentTarget::ObjectAssignmentTarget(_)
+        ) {
+            if assign.operator != AssignmentOperator::Assign {
+                return Err("compound destructuring assignment not supported".into());
+            }
+            let val_reg = self.emit_expression(&assign.right, ctx)?;
+            self.emit_assign_target(&assign.left, val_reg, ctx)?;
+            Ok(val_reg)
+        } else {
+            Err("assignment target not supported".into())
+        }
+    }
+}

crates/oxide_emit/src/expr/call.rs

@@ -0,0 +1,123 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::Expression;
+
+impl Emitter {
+    fn emit_call_expression(&self, call: &oxide_parser::CallExpression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        if matches!(&call.callee, Expression::Super(_)) {
+            if !ctx.in_derived_constructor {
+                return Err("super() only supported in derived constructors".into());
+            }
+            let mut arg_regs = Vec::new();
+            for arg in &call.arguments {
+                if let Some(expr) = arg.as_expression() {
+                    arg_regs.push(self.emit_expression(expr, ctx)?);
+                }
+            }
+            let first_arg_reg = if arg_regs.is_empty() { 0u8 } else { arg_regs[0] };
+            let result_reg = ctx.alloc_reg();
+            ctx.inst(Inst::super_call(
+                Operand::Reg(result_reg as u32),
+                Operand::Reg(first_arg_reg as u32),
+                arg_regs.len() as u8,
+            ));
+            if let Some(mut field_buffer) = ctx.field_buffer.take() {
+                let insert_inst = ctx.insts.len();
+                ctx.insts.append(&mut field_buffer.insts);
+                for (label, relative) in field_buffer.labels {
+                    ctx.labels.set_label_pos(label, insert_inst + relative);
+                }
+            }
+            return Ok(result_reg);
+        }
+        let (callee_reg, this_reg) = match &call.callee {
+            Expression::PrivateFieldExpression(member) => {
+                let obj_reg = self.emit_expression(&member.object, ctx)?;
+                let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
+                let callee_reg = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::GET_PRIVATE, Operand::Reg(callee_reg as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+                (callee_reg, obj_reg)
+            }
+            Expression::StaticMemberExpression(member) => {
+                let is_super_member = matches!(&member.object, Expression::Super(_));
+                let obj_reg = if is_super_member {
+                    let this_reg = ctx.alloc_reg();
+                    ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(this_reg as u32), Operand::This, Operand::None));
+                    this_reg
+                } else {
+                    self.emit_expression(&member.object, ctx)?
+                };
+                let prop_name = member.property.name.as_str();
+                let idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+                let key_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), idx));
+                let callee_reg = ctx.alloc_reg();
+                if is_super_member {
+                    if !ctx.in_instance_method && !ctx.in_static_method && !ctx.in_derived_constructor {
+                        return Err("super property only supported in class methods".into());
+                    }
+                    let op = if ctx.in_static_method {
+                        OpCode::SUPER_STATIC_GET_PROP
+                    } else {
+                        OpCode::SUPER_GET_PROP
+                    };
+                    ctx.inst(Inst::new(op, Operand::Reg(callee_reg as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+                } else {
+                    ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(callee_reg as u32), Operand::Reg(obj_reg as u32), Operand::None));
+                    ctx.inst(Inst::ic_get(Operand::Reg(callee_reg as u32), Operand::Reg(key_reg as u32)));
+                }
+                (callee_reg, obj_reg)
+            }
+            _ => {
+                let callee_reg = self.emit_expression(&call.callee, ctx)?;
+                let this_idx = ctx.add_constant(Constant::Undefined);
+                let this_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(this_reg as u32), this_idx));
+                (callee_reg, this_reg)
+            }
+        };
+        let mut arg_regs = Vec::new();
+        for arg in &call.arguments {
+            if let Some(expr) = arg.as_expression() {
+                arg_regs.push(self.emit_expression(expr, ctx)?);
+            }
+        }
+        let first_arg_reg = if arg_regs.is_empty() { 0u8 } else { arg_regs[0] };
+        let op = match &call.callee {
+            Expression::Identifier(ident) if ctx.is_builtin(ident.name.as_str()) => OpCode::CALL_NATIVE,
+            _ => OpCode::CALL,
+        };
+        match op {
+            OpCode::CALL => {
+                ctx.inst(Inst::call(
+                    Operand::Reg(callee_reg as u32),
+                    Operand::Reg(this_reg as u32),
+                    Operand::Reg(first_arg_reg as u32),
+                    arg_regs.len() as u8,
+                ));
+            }
+            OpCode::CALL_NATIVE => {
+                ctx.inst(Inst::call_native(
+                    Operand::Reg(callee_reg as u32),
+                    Operand::Reg(this_reg as u32),
+                    Operand::Reg(first_arg_reg as u32),
+                    arg_regs.len() as u8,
+                ));
+            }
+            _ => unreachable!(),
+        }
+        let result_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::None, Operand::None));
+        Ok(result_reg)
+    }
+
+    pub(crate) fn emit_call_domain(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match expr {
+            Expression::CallExpression(call) => self.emit_call_expression(call, ctx),
+            _ => self.emit_unsupported_expression(expr, ctx),
+        }
+    }
+}

crates/oxide_emit/src/expr/function/mod.rs

@@ -0,0 +1,112 @@
+use crate::{CompileCtx, Emitter, ParamSpec};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_parser::{Class, Expression, Statement};
+
+impl Emitter {
+    fn emit_arrow_function_expression(
+        &self, arrow: &oxide_parser::ArrowFunctionExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        // Rest params not yet supported
+        if let Some(_rest) = &arrow.params.rest {
+            return Err("rest params in arrow functions not yet supported".into());
+        }
+
+        // Extract param names (same pattern as FunctionExpression)
+        let mut param_names = Vec::new();
+        for (idx, param) in arrow.params.items.iter().enumerate() {
+            match &param.pattern {
+                oxide_parser::BindingPattern::BindingIdentifier(bi) => {
+                    param_names.push(ParamSpec::Identifier(bi.name.to_string()));
+                }
+                pattern => {
+                    param_names.push(ParamSpec::Pattern {
+                        synthetic_name: format!("@@param_{idx}"),
+                        pattern,
+                    });
+                }
+            }
+        }
+
+        // Expression body: pass body statements directly with is_expression_body=true.
+        // Statement body: pass body statements with is_expression_body=false.
+        let body_stmts = &arrow.body.statements;
+        let is_expr_body = arrow.expression;
+
+        let mut sub_module = self.compile_function_body(&param_names, body_stmts, ctx, is_expr_body, true)?;
+        sub_module.is_arrow = true;
+
+        ctx.nested.push(sub_module);
+        // 1-indexed: 0 = no sub_module (sentinel)
+        let sub_idx = ctx.nested.len() as u16;
+
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::create_closure(Operand::Reg(r as u32), sub_idx));
+        Ok(r)
+    }
+
+    fn emit_function_expression(&self, fe: &oxide_parser::Function, ctx: &mut CompileCtx) -> Result<u8, String> {
+        // FunctionExpression: compile body, emit LOAD_CONST(BytecodeFunc)
+        let mut param_names = Vec::new();
+        for (idx, param) in fe.params.items.iter().enumerate() {
+            match &param.pattern {
+                oxide_parser::BindingPattern::BindingIdentifier(bi) => {
+                    param_names.push(ParamSpec::Identifier(bi.name.to_string()));
+                }
+                pattern => {
+                    param_names.push(ParamSpec::Pattern {
+                        synthetic_name: format!("@@param_{idx}"),
+                        pattern,
+                    });
+                }
+            }
+        }
+
+        let body_stmts: &[Statement] = if let Some(body) = &fe.body { &body.statements } else { &[] };
+
+        let mut sub_module = self.compile_function_body(&param_names, body_stmts, ctx, false, false)?;
+        if let Some(id) = &fe.id {
+            sub_module.function_name = Some(id.name.to_string());
+        }
+        ctx.nested.push(sub_module);
+        // 1-indexed: 0 = no sub_module (sentinel)
+        let sub_idx = ctx.nested.len() as u16;
+
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::create_closure(Operand::Reg(r as u32), sub_idx));
+        Ok(r)
+    }
+
+    fn emit_class_expression(&self, class: &Class, ctx: &mut CompileCtx) -> Result<u8, String> {
+        self.emit_class(class, ctx)
+    }
+
+    fn emit_new_expression(&self, ne: &oxide_parser::NewExpression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let constructor_reg = self.emit_expression(&ne.callee, ctx)?;
+        let mut arg_regs = Vec::new();
+        for arg in &ne.arguments {
+            if let Some(expr) = arg.as_expression() {
+                arg_regs.push(self.emit_expression(expr, ctx)?);
+            }
+        }
+        let first_arg_reg = if arg_regs.is_empty() { 0u8 } else { arg_regs[0] };
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::new_expression(
+            Operand::Reg(r as u32),
+            Operand::Reg(constructor_reg as u32),
+            Operand::Reg(first_arg_reg as u32),
+            arg_regs.len() as u8,
+        ));
+        Ok(r)
+    }
+
+    pub(crate) fn emit_function_domain(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match expr {
+            Expression::ArrowFunctionExpression(arrow) => self.emit_arrow_function_expression(arrow, ctx),
+            Expression::FunctionExpression(fe) => self.emit_function_expression(fe, ctx),
+            Expression::ClassExpression(class) => self.emit_class_expression(class, ctx),
+            Expression::NewExpression(ne) => self.emit_new_expression(ne, ctx),
+            _ => self.emit_unsupported_expression(expr, ctx),
+        }
+    }
+}

crates/oxide_emit/src/expr/identifier.rs

@@ -0,0 +1,36 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+
+impl Emitter {
+    pub(crate) fn emit_identifier_expression(
+        &self, ident: &oxide_parser::IdentifierReference, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let name = ident.name.as_str();
+
+        for (uv_idx, up) in ctx.current_upvalue_captures.iter().enumerate() {
+            if up.name == name {
+                let r = ctx.alloc_reg();
+                let idx = uv_idx as u8;
+                ctx.inst(Inst::new(OpCode::LOAD_UPVALUE, Operand::Reg(r as u32), Operand::Reg(idx as u32), Operand::None));
+                return Ok(r);
+            }
+        }
+
+        if let Some(&cell_idx) = ctx.captured_bindings.get(name) {
+            let r = ctx.alloc_reg();
+            if let Some((binding, _)) = ctx.scopes.symbols.lookup_any_binding(name) {
+                ctx.inst(Inst::new(OpCode::CELL_GET, Operand::Reg(r as u32), Operand::Reg(binding.reg as u32), Operand::Imm(cell_idx as u16)));
+            } else {
+                ctx.inst(Inst::new(OpCode::CELL_GET, Operand::Reg(r as u32), Operand::None, Operand::Imm(cell_idx as u16)));
+            }
+            return Ok(r);
+        }
+
+        let var_reg = ctx.lookup_or_builtin(name)?;
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(r as u32), Operand::Reg(var_reg as u32), Operand::None));
+        Ok(r)
+    }
+}

crates/oxide_emit/src/expr/literal.rs

@@ -0,0 +1,83 @@
+use crate::{is_int_literal, CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::Expression;
+
+impl Emitter {
+    pub(crate) fn emit_literal(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match expr {
+            Expression::NumericLiteral(n) => self.emit_numeric_literal_expression(n, ctx),
+            Expression::StringLiteral(s) => self.emit_string_literal_expression(s, ctx),
+            Expression::BooleanLiteral(b) => self.emit_boolean_literal_expression(b, ctx),
+            Expression::NullLiteral(_) => self.emit_null_literal_expression(ctx),
+            Expression::RegExpLiteral(lit) => self.emit_reg_exp_literal_expression(lit, ctx),
+            _ => self.emit_unsupported_expression(expr, ctx),
+        }
+    }
+
+    fn emit_numeric_literal_expression(
+        &self, n: &oxide_parser::NumericLiteral, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let idx = if is_int_literal(n.value) {
+            ctx.add_constant(Constant::Int(n.value as i32))
+        } else {
+            ctx.add_constant(Constant::Number(n.value))
+        };
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(r as u32), idx));
+        Ok(r)
+    }
+
+    fn emit_string_literal_expression(
+        &self, s: &oxide_parser::StringLiteral, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let idx = ctx.add_constant(Constant::String(s.value.to_string()));
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(r as u32), idx));
+        Ok(r)
+    }
+
+    fn emit_boolean_literal_expression(
+        &self, b: &oxide_parser::BooleanLiteral, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let idx = ctx.add_constant(Constant::Boolean(b.value));
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(r as u32), idx));
+        Ok(r)
+    }
+
+    fn emit_null_literal_expression(&self, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let idx = ctx.add_constant(Constant::Null);
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(r as u32), idx));
+        Ok(r)
+    }
+
+    fn emit_reg_exp_literal_expression(
+        &self, lit: &oxide_parser::RegExpLiteral, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        if let Some(raw) = &lit.raw {
+            let raw_str = raw.to_string();
+            if raw_str.len() >= 2 && raw_str.starts_with('/') {
+                let last_slash = raw_str.rfind('/').unwrap_or(raw_str.len() - 1);
+                let pattern = raw_str[1..last_slash].to_string();
+                let flags = raw_str[last_slash + 1..].to_string();
+                let pat_ci = ctx.add_constant(Constant::String(pattern));
+                let pat_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(pat_reg as u32), pat_ci));
+                let flags_ci = ctx.add_constant(Constant::String(flags));
+                let flags_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(flags_reg as u32), flags_ci));
+                let r = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::CREATE_REGEXP, Operand::Reg(r as u32), Operand::Reg(pat_reg as u32), Operand::Reg(flags_reg as u32)));
+                Ok(r)
+            } else {
+                Err(format!("unsupported regexp literal: {:?}", lit))
+            }
+        } else {
+            Err(format!("unsupported regexp literal: {:?}", lit))
+        }
+    }
+}

crates/oxide_emit/src/expr/member/mod.rs

@@ -0,0 +1,83 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::Expression;
+
+impl Emitter {
+    fn emit_static_member_expression(
+        &self, member: &oxide_parser::StaticMemberExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        if matches!(&member.object, Expression::Super(_)) {
+            if !ctx.in_instance_method && !ctx.in_static_method && !ctx.in_derived_constructor {
+                return Err("super property only supported in class methods".into());
+            }
+            let prop_name = member.property.name.as_str();
+            let idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+            let key_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), idx));
+            let this_reg = ctx.alloc_reg();
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(this_reg as u32), Operand::This, Operand::None));
+            let result_reg = ctx.alloc_reg();
+            let op = if ctx.in_static_method {
+                OpCode::SUPER_STATIC_GET_PROP
+            } else {
+                OpCode::SUPER_GET_PROP
+            };
+            ctx.inst(Inst::new(op, Operand::Reg(result_reg as u32), Operand::Reg(this_reg as u32), Operand::Reg(key_reg as u32)));
+            return Ok(result_reg);
+        }
+        let obj_reg = self.emit_expression(&member.object, ctx)?;
+        let prop_name = member.property.name.as_str();
+        let idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+        let key_reg = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), idx));
+        ctx.inst(Inst::ic_get(Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+        Ok(obj_reg)
+    }
+
+    fn emit_computed_member_expression(
+        &self, member: &oxide_parser::ComputedMemberExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let obj_reg = self.emit_expression(&member.object, ctx)?;
+        let key_reg = self.emit_expression(&member.expression, ctx)?;
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::GET_PROP_DYNAMIC, Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32), Operand::Reg(r as u32)));
+        Ok(r)
+    }
+
+    fn emit_private_field_expression(
+        &self, member: &oxide_parser::PrivateFieldExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let obj_reg = self.emit_expression(&member.object, ctx)?;
+        let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
+        let r = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::GET_PRIVATE, Operand::Reg(r as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+        Ok(r)
+    }
+
+    fn emit_chain_expression(&self, chain: &oxide_parser::ChainExpression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let short_label = ctx.next_label_id();
+        let end_label = ctx.next_label_id();
+        let value_reg = self.emit_chain_element(&chain.expression, Some(short_label), ctx)?;
+        let result_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(value_reg as u32), Operand::None));
+        ctx.inst(Inst::jmp(end_label));
+        ctx.labels.set_label_pos(short_label, ctx.insts.len());
+        let undefined_idx = ctx.add_constant(Constant::Undefined);
+        ctx.inst(Inst::load_const(Operand::Reg(result_reg as u32), undefined_idx));
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+        Ok(result_reg)
+    }
+
+    pub(crate) fn emit_member_domain(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match expr {
+            Expression::StaticMemberExpression(member) => self.emit_static_member_expression(member, ctx),
+            Expression::ComputedMemberExpression(member) => self.emit_computed_member_expression(member, ctx),
+            Expression::PrivateFieldExpression(member) => self.emit_private_field_expression(member, ctx),
+            Expression::ChainExpression(chain) => self.emit_chain_expression(chain, ctx),
+            _ => self.emit_unsupported_expression(expr, ctx),
+        }
+    }
+}

crates/oxide_emit/src/expr/mod.rs

@@ -0,0 +1,31 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Expression;
+
+pub mod assignment;
+pub mod call;
+pub mod function;
+pub mod identifier;
+pub mod literal;
+pub mod member;
+pub mod object;
+pub mod operator;
+pub mod parenthesized;
+pub mod template;
+pub mod this;
+
+impl Emitter {
+    pub(crate) fn emit_unsupported_expression(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let _ = ctx;
+        Err(format!("unsupported expression type: {:?}", expr))
+    }
+
+    pub(crate) fn emit_sequence_expression(
+        &self, seq: &oxide_parser::SequenceExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let mut last = 0u8;
+        for e in &seq.expressions {
+            last = self.emit_expression(e, ctx)?;
+        }
+        Ok(last)
+    }
+}

crates/oxide_emit/src/expr/object/array.rs

@@ -0,0 +1,27 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+impl Emitter {
+    pub(crate) fn emit_array_expression(
+        &self, arr: &oxide_parser::ArrayExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let arr_reg = ctx.alloc_reg();
+        let n = arr.elements.len() as u16;
+        ctx.inst(Inst::new(OpCode::NEW_ARRAY, Operand::Reg(arr_reg as u32), Operand::Imm(n), Operand::None));
+        let elem_checkpoint = ctx.reg_checkpoint();
+        for (i, elem) in arr.elements.iter().enumerate() {
+            let Some(e) = elem.as_expression() else {
+                return Err("spread not supported".into());
+            };
+            let val_reg = self.emit_expression(e, ctx)?;
+            let idx_reg = ctx.alloc_reg();
+            let idx = ctx.add_constant(Constant::Int(i as i32));
+            ctx.inst(Inst::load_const(Operand::Reg(idx_reg as u32), idx));
+            ctx.inst(Inst::new(OpCode::SET_ELEM, Operand::Reg(arr_reg as u32), Operand::Reg(idx_reg as u32), Operand::Reg(val_reg as u32)));
+            ctx.restore_reg_checkpoint(elem_checkpoint);
+        }
+        Ok(arr_reg)
+    }
+}

crates/oxide_emit/src/expr/object/mod.rs

@@ -0,0 +1,15 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Expression;
+
+mod array;
+mod object_literal;
+
+impl Emitter {
+    pub(crate) fn emit_object_domain(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match expr {
+            Expression::ObjectExpression(obj) => self.emit_object_expression(obj, ctx),
+            Expression::ArrayExpression(arr) => self.emit_array_expression(arr, ctx),
+            _ => self.emit_unsupported_expression(expr, ctx),
+        }
+    }
+}

crates/oxide_emit/src/expr/object/object_literal.rs

@@ -0,0 +1,62 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{Expression, ObjectPropertyKind, PropertyKey, PropertyKind};
+
+impl Emitter {
+    pub(crate) fn emit_object_expression(
+        &self, obj: &oxide_parser::ObjectExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let obj_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::NEW_OBJECT, Operand::Reg(obj_reg as u32), Operand::None, Operand::None));
+        let prop_checkpoint = ctx.reg_checkpoint();
+        for prop in &obj.properties {
+            let ObjectPropertyKind::ObjectProperty(p) = prop else {
+                return Err("spread properties not yet supported".into());
+            };
+            let prop_name = match &p.key {
+                PropertyKey::StaticIdentifier(ident) => ident.name.as_str().to_string(),
+                PropertyKey::StringLiteral(s) => s.value.to_string(),
+                _ => return Err("unsupported object property key type".into()),
+            };
+            match p.kind {
+                PropertyKind::Get | PropertyKind::Set => {
+                    let accessor_reg = self.emit_expression(&p.value, ctx)?;
+                    if let Some(sub_mod) = ctx.nested.last_mut() {
+                        sub_mod.function_name = Some(prop_name.to_string());
+                    }
+                    let undef_reg = self.emit_undefined(ctx);
+                    let (get_reg, set_reg) = if p.kind == PropertyKind::Get {
+                        (accessor_reg, undef_reg)
+                    } else {
+                        (undef_reg, accessor_reg)
+                    };
+                    let idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+                    ctx.inst(Inst::define_accessor(
+                        Operand::Reg(obj_reg as u32),
+                        Operand::Reg(get_reg as u32),
+                        Operand::Reg(set_reg as u32),
+                        idx as u32,
+                    ));
+                    ctx.restore_reg_checkpoint(prop_checkpoint);
+                }
+                _ => {
+                    let idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+                    let key_reg = ctx.alloc_reg();
+                    ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), idx));
+                    let val_reg = self.emit_expression(&p.value, ctx)?;
+                    if matches!(&p.value, Expression::ArrowFunctionExpression(_)) {
+                        if let Some(sub_mod) = ctx.nested.last_mut() {
+                            sub_mod.function_name = Some(prop_name.to_string());
+                        }
+                    }
+                    ctx.inst(Inst::new(OpCode::SET_PROP, Operand::Reg(obj_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(key_reg as u32)));
+                    ctx.restore_reg_checkpoint(prop_checkpoint);
+                }
+            }
+        }
+        Ok(obj_reg)
+    }
+}

crates/oxide_emit/src/expr/operator/mod.rs

@@ -0,0 +1,321 @@
+use crate::{is_side_effect_free, BinaryOperator, CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{ChainElement, Expression, LogicalOperator, SimpleAssignmentTarget, UnaryOperator, UpdateOperator};
+
+impl Emitter {
+    fn emit_private_in_expression(
+        &self, pin: &oxide_parser::PrivateInExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let obj_reg = self.emit_expression(&pin.right, ctx)?;
+        let key_reg = self.emit_private_id_reg(pin.left.name.as_str(), ctx)?;
+        let result_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::PRIVATE_BRAND_IN, Operand::Reg(result_reg as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+        Ok(result_reg)
+    }
+
+    fn emit_binary_expression(&self, bin: &oxide_parser::BinaryExpression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let checkpoint = ctx.reg_checkpoint();
+        let left = self.emit_expression(&bin.left, ctx)?;
+        let right = self.emit_expression(&bin.right, ctx)?;
+        let op = match bin.operator {
+            BinaryOperator::Addition => OpCode::ADD,
+            BinaryOperator::Subtraction => OpCode::SUB,
+            BinaryOperator::Multiplication => OpCode::MUL,
+            BinaryOperator::Division => OpCode::DIV,
+            BinaryOperator::Remainder => OpCode::MOD,
+            BinaryOperator::BitwiseAnd => OpCode::BIT_AND,
+            BinaryOperator::BitwiseOR => OpCode::BIT_OR,
+            BinaryOperator::BitwiseXOR => OpCode::BIT_XOR,
+            BinaryOperator::ShiftLeft => OpCode::SHL,
+            BinaryOperator::ShiftRight => OpCode::SHR,
+            BinaryOperator::ShiftRightZeroFill => OpCode::USHR,
+            BinaryOperator::Equality => OpCode::EQ,
+            BinaryOperator::Inequality => OpCode::NEQ,
+            BinaryOperator::LessThan => OpCode::LT,
+            BinaryOperator::GreaterThan => OpCode::GT,
+            BinaryOperator::LessEqualThan => OpCode::LTE,
+            BinaryOperator::GreaterEqualThan => OpCode::GTE,
+            BinaryOperator::In => OpCode::IN,
+            BinaryOperator::Instanceof => OpCode::INSTANCEOF,
+            BinaryOperator::StrictEquality => OpCode::STRICT_EQ,
+            BinaryOperator::StrictInequality => OpCode::STRICT_NEQ,
+            _ => return Err(format!("unsupported binary operator: {:?}", bin.operator)),
+        };
+        ctx.inst(Inst::new(op, Operand::Reg(left as u32), Operand::Reg(left as u32), Operand::Reg(right as u32)));
+        if is_side_effect_free(&bin.left) && is_side_effect_free(&bin.right) {
+            ctx.restore_reg_checkpoint(checkpoint.saturating_add(1).max(left.saturating_add(1)));
+        }
+        Ok(left)
+    }
+
+    fn emit_unary_expression(&self, un: &oxide_parser::UnaryExpression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        if matches!(un.operator, UnaryOperator::Delete) {
+            return match &un.argument {
+                Expression::Identifier(_) => {
+                    Err("SyntaxError: delete of an unqualified identifier in strict mode".into())
+                }
+                Expression::StaticMemberExpression(member) => {
+                    let obj_reg = self.emit_expression(&member.object, ctx)?;
+                    let prop_name = member.property.name.as_str();
+                    let const_idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+                    ctx.inst(Inst::delete_prop_static(Operand::Reg(obj_reg as u32), const_idx as u32));
+                    Ok(obj_reg)
+                }
+                Expression::ComputedMemberExpression(member) => {
+                    let obj_reg = self.emit_expression(&member.object, ctx)?;
+                    let key_reg = self.emit_expression(&member.expression, ctx)?;
+                    ctx.inst(Inst::new(OpCode::DELETE_PROP_DYNAMIC, Operand::Reg(obj_reg as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+                    Ok(obj_reg)
+                }
+                Expression::ChainExpression(chain) => {
+                    let short_label = ctx.next_label_id();
+                    let result_reg = match &chain.expression {
+                        ChainElement::StaticMemberExpression(member) => {
+                            let obj_reg = self.emit_expression(&member.object, ctx)?;
+                            if member.optional {
+                                let dup_reg = ctx.alloc_reg();
+                                ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(dup_reg as u32), Operand::Reg(obj_reg as u32), Operand::None));
+                                ctx.inst(Inst::jmp_if_nullish(dup_reg, short_label));
+                            }
+                            let prop_name = member.property.name.as_str();
+                            let const_idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+                            ctx.inst(Inst::delete_prop_static(Operand::Reg(obj_reg as u32), const_idx as u32));
+                            obj_reg
+                        }
+                        ChainElement::ComputedMemberExpression(member) => {
+                            let obj_reg = self.emit_expression(&member.object, ctx)?;
+                            if member.optional {
+                                let dup_reg = ctx.alloc_reg();
+                                ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(dup_reg as u32), Operand::Reg(obj_reg as u32), Operand::None));
+                                ctx.inst(Inst::jmp_if_nullish(dup_reg, short_label));
+                            }
+                            let key_reg = self.emit_expression(&member.expression, ctx)?;
+                            ctx.inst(Inst::new(OpCode::DELETE_PROP_DYNAMIC, Operand::Reg(obj_reg as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+                            obj_reg
+                        }
+                        _ => return Err("invalid delete target".into()),
+                    };
+                    let end_label = ctx.next_label_id();
+                    ctx.inst(Inst::jmp(end_label));
+                    ctx.labels.set_label_pos(short_label, ctx.insts.len());
+                    let true_idx = ctx.add_constant(Constant::Boolean(true));
+                    ctx.inst(Inst::load_const(Operand::Reg(result_reg as u32), true_idx));
+                    ctx.labels.set_label_pos(end_label, ctx.insts.len());
+                    Ok(result_reg)
+                }
+                _ => Err("invalid delete target".into()),
+            };
+        }
+        let arg = self.emit_expression(&un.argument, ctx)?;
+        match un.operator {
+            UnaryOperator::UnaryNegation => {
+                ctx.inst(Inst::new(OpCode::NEG, Operand::Reg(arg as u32), Operand::Reg(arg as u32), Operand::None));
+                Ok(arg)
+            }
+            UnaryOperator::Typeof => {
+                ctx.inst(Inst::new(OpCode::TYPEOF, Operand::Reg(arg as u32), Operand::Reg(arg as u32), Operand::None));
+                Ok(arg)
+            }
+            UnaryOperator::Void => {
+                ctx.inst(Inst::new(OpCode::VOID, Operand::Reg(arg as u32), Operand::Reg(arg as u32), Operand::None));
+                Ok(arg)
+            }
+            UnaryOperator::LogicalNot => {
+                ctx.inst(Inst::new(OpCode::NOT, Operand::Reg(arg as u32), Operand::Reg(arg as u32), Operand::None));
+                Ok(arg)
+            }
+            UnaryOperator::BitwiseNot => {
+                ctx.inst(Inst::new(OpCode::BIT_NOT, Operand::Reg(arg as u32), Operand::Reg(arg as u32), Operand::None));
+                Ok(arg)
+            }
+            UnaryOperator::UnaryPlus => {
+                ctx.inst(Inst::new(OpCode::UNARY_PLUS, Operand::Reg(arg as u32), Operand::Reg(arg as u32), Operand::None));
+                Ok(arg)
+            }
+            UnaryOperator::Delete => Err("invalid delete target".into()),
+        }
+    }
+
+    fn emit_conditional_expression(
+        &self, cond: &oxide_parser::ConditionalExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let else_label = ctx.next_label_id();
+        let end_label = ctx.next_label_id();
+
+        let test_reg = self.emit_expression(&cond.test, ctx)?;
+        ctx.inst(Inst::jmp_if_false(test_reg, else_label));
+
+        let cons_reg = self.emit_expression(&cond.consequent, ctx)?;
+        let result_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(cons_reg as u32), Operand::None));
+
+        ctx.inst(Inst::jmp(end_label));
+
+        ctx.labels.set_label_pos(else_label, ctx.insts.len());
+        let alt_reg = self.emit_expression(&cond.alternate, ctx)?;
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(alt_reg as u32), Operand::None));
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+
+        Ok(result_reg)
+    }
+
+    fn emit_logical_expression(
+        &self, log: &oxide_parser::LogicalExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let left_reg = self.emit_expression(&log.left, ctx)?;
+
+        if is_side_effect_free(&log.left) && is_side_effect_free(&log.right) {
+            let right_reg = self.emit_expression(&log.right, ctx)?;
+            let r = ctx.alloc_reg();
+            let op = match log.operator {
+                LogicalOperator::And => OpCode::AND,
+                LogicalOperator::Or => OpCode::OR,
+                LogicalOperator::Coalesce => OpCode::NULLISH,
+            };
+            ctx.inst(Inst::new(op, Operand::Reg(r as u32), Operand::Reg(left_reg as u32), Operand::Reg(right_reg as u32)));
+            return Ok(r);
+        }
+
+        if matches!(log.operator, LogicalOperator::Coalesce) {
+            let rhs_label = ctx.next_label_id();
+            let end_label = ctx.next_label_id();
+            let dup_reg = ctx.alloc_reg();
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(dup_reg as u32), Operand::Reg(left_reg as u32), Operand::None));
+            ctx.inst(Inst::jmp_if_nullish(dup_reg, rhs_label));
+            ctx.inst(Inst::jmp(end_label));
+            ctx.labels.set_label_pos(rhs_label, ctx.insts.len());
+            let right_reg = self.emit_expression(&log.right, ctx)?;
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(dup_reg as u32), Operand::Reg(right_reg as u32), Operand::None));
+            ctx.labels.set_label_pos(end_label, ctx.insts.len());
+            return Ok(dup_reg);
+        }
+
+        let skip_label = match log.operator {
+            LogicalOperator::And => ctx.next_label_id(),
+            LogicalOperator::Or => ctx.next_label_id(),
+            LogicalOperator::Coalesce => return Err("invalid logical operator dispatch".into()),
+        };
+        let dup_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(dup_reg as u32), Operand::Reg(left_reg as u32), Operand::None));
+
+        match log.operator {
+            LogicalOperator::And => ctx.inst(Inst::jmp_if_false(dup_reg, skip_label)),
+            LogicalOperator::Or => ctx.inst(Inst::jmp_if_true(dup_reg, skip_label)),
+            LogicalOperator::Coalesce => return Err("invalid logical operator dispatch".into()),
+        }
+
+        let right_reg = self.emit_expression(&log.right, ctx)?;
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(dup_reg as u32), Operand::Reg(right_reg as u32), Operand::None));
+        ctx.labels.set_label_pos(skip_label, ctx.insts.len());
+
+        Ok(dup_reg)
+    }
+
+    fn emit_update_expression(
+        &self, update: &oxide_parser::UpdateExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        match &update.argument {
+            SimpleAssignmentTarget::AssignmentTargetIdentifier(id) => {
+                let name = id.name.as_str();
+                // Check if this is an upvalue or captured cell reference
+                let uv_idx = ctx.current_upvalue_captures.iter().position(|u| u.name == name);
+                let captured_cell = ctx.captured_bindings.get(name).copied();
+                if let Some(uv) = uv_idx {
+                    // Upvalue: LOAD_UPVALUE + CONST(1) + ADD/SUB + STORE_UPVALUE
+                    let val_reg = ctx.alloc_reg();
+                    ctx.inst(Inst::new(OpCode::LOAD_UPVALUE, Operand::Reg(val_reg as u32), Operand::Imm(uv as u16), Operand::None));
+                    let one_idx = ctx.add_constant(Constant::Int(1));
+                    let one_reg = ctx.alloc_reg();
+                    ctx.inst(Inst::load_const(Operand::Reg(one_reg as u32), one_idx));
+                    let op = if update.operator == UpdateOperator::Increment {
+                        OpCode::ADD
+                    } else {
+                        OpCode::SUB
+                    };
+                    ctx.inst(Inst::new(op, Operand::Reg(val_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(one_reg as u32)));
+                    ctx.inst(Inst::new(OpCode::STORE_UPVALUE, Operand::None, Operand::Reg(val_reg as u32), Operand::Imm(uv as u16)));
+                    Ok(val_reg)
+                } else if let Some(cell_idx) = captured_cell {
+                    // Captured cell: CELL_GET + CONST(1) + ADD/SUB + CELL_SET
+                    let val_reg = ctx.alloc_reg();
+                    if let Some((binding, _)) = ctx.scopes.symbols.lookup_any_binding(name) {
+                        ctx.inst(Inst::new(OpCode::CELL_GET, Operand::Reg(val_reg as u32), Operand::Reg(binding.reg as u32), Operand::Imm(cell_idx as u16)));
+                    } else {
+                        ctx.inst(Inst::new(OpCode::CELL_GET, Operand::Reg(val_reg as u32), Operand::None, Operand::Imm(cell_idx as u16)));
+                    }
+                    let one_idx = ctx.add_constant(Constant::Int(1));
+                    let one_reg = ctx.alloc_reg();
+                    ctx.inst(Inst::load_const(Operand::Reg(one_reg as u32), one_idx));
+                    let op = if update.operator == UpdateOperator::Increment {
+                        OpCode::ADD
+                    } else {
+                        OpCode::SUB
+                    };
+                    ctx.inst(Inst::new(op, Operand::Reg(val_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(one_reg as u32)));
+                    ctx.inst(Inst::new(OpCode::CELL_SET, Operand::None, Operand::Reg(val_reg as u32), Operand::Imm(cell_idx as u16)));
+                    Ok(val_reg)
+                } else {
+                    let var_reg = ctx.lookup_or_global(name);
+                    let result_reg = ctx.alloc_reg();
+                    let op = match (update.operator, update.prefix) {
+                        (UpdateOperator::Increment, true) => OpCode::INC_PRE,
+                        (UpdateOperator::Increment, false) => OpCode::INC_POST,
+                        (UpdateOperator::Decrement, true) => OpCode::DEC_PRE,
+                        (UpdateOperator::Decrement, false) => OpCode::DEC_POST,
+                    };
+                    ctx.inst(Inst::new(op, Operand::Reg(var_reg as u32), Operand::Reg(result_reg as u32), Operand::Reg(result_reg as u32)));
+                    Ok(result_reg)
+                }
+            }
+            SimpleAssignmentTarget::StaticMemberExpression(member) => {
+                let obj_reg = self.emit_expression(&member.object, ctx)?;
+                let prop_name = member.property.name.as_str();
+                let key_idx = ctx.add_constant(Constant::String(prop_name.to_string()));
+                let key_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), key_idx));
+                let val_reg = ctx.alloc_reg();
+                let op = match update.operator {
+                    UpdateOperator::Increment => OpCode::MEMBER_INC,
+                    UpdateOperator::Decrement => OpCode::MEMBER_DEC,
+                };
+                match op {
+                    OpCode::MEMBER_INC => {
+                        ctx.inst(Inst::member_inc(Operand::Reg(obj_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(key_reg as u32)));
+                    }
+                    OpCode::MEMBER_DEC => {
+                        ctx.inst(Inst::member_dec(Operand::Reg(obj_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(key_reg as u32)));
+                    }
+                    _ => unreachable!(),
+                }
+                Ok(val_reg)
+            }
+            SimpleAssignmentTarget::ComputedMemberExpression(member) => {
+                let obj_reg = self.emit_expression(&member.object, ctx)?;
+                let key_reg = self.emit_expression(&member.expression, ctx)?;
+                let val_reg = ctx.alloc_reg();
+                let op = match update.operator {
+                    UpdateOperator::Increment => OpCode::DYN_MEMBER_INC,
+                    UpdateOperator::Decrement => OpCode::DYN_MEMBER_DEC,
+                };
+                ctx.inst(Inst::new(op, Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32), Operand::Reg(val_reg as u32)));
+                Ok(val_reg)
+            }
+            _ => Err("member update not yet supported".into()),
+        }
+    }
+
+    pub(crate) fn emit_operator(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match expr {
+            Expression::BinaryExpression(bin) => self.emit_binary_expression(bin, ctx),
+            Expression::PrivateInExpression(pin) => self.emit_private_in_expression(pin, ctx),
+            Expression::UnaryExpression(un) => self.emit_unary_expression(un, ctx),
+            Expression::ConditionalExpression(cond) => self.emit_conditional_expression(cond, ctx),
+            Expression::LogicalExpression(log) => self.emit_logical_expression(log, ctx),
+            Expression::UpdateExpression(update) => self.emit_update_expression(update, ctx),
+            _ => self.emit_unsupported_expression(expr, ctx),
+        }
+    }
+}

crates/oxide_emit/src/expr/parenthesized.rs

@@ -0,0 +1,9 @@
+use crate::{CompileCtx, Emitter};
+
+impl Emitter {
+    pub(crate) fn emit_parenthesized_expression(
+        &self, p: &oxide_parser::ParenthesizedExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        self.emit_expression(&p.expression, ctx)
+    }
+}

crates/oxide_emit/src/expr/template/mod.rs

@@ -0,0 +1,15 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Expression;
+
+mod tagged;
+mod template_literal;
+
+impl Emitter {
+    pub(crate) fn emit_template_domain(&self, expr: &Expression, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match expr {
+            Expression::TemplateLiteral(tl) => self.emit_template_literal_expression(tl, ctx),
+            Expression::TaggedTemplateExpression(tt) => self.emit_tagged_template_expression(tt, ctx),
+            _ => self.emit_unsupported_expression(expr, ctx),
+        }
+    }
+}

crates/oxide_emit/src/expr/template/tagged.rs

@@ -0,0 +1,75 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+impl Emitter {
+    pub(crate) fn emit_tagged_template_expression(
+        &self, tt: &oxide_parser::TaggedTemplateExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let quasis = &tt.quasi.quasis;
+        let expressions = &tt.quasi.expressions;
+
+        let tag_reg = self.emit_expression(&tt.tag, ctx)?;
+
+        let cooked_temp = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::NEW_ARRAY, Operand::Reg(cooked_temp as u32), Operand::Imm(quasis.len() as u16), Operand::None));
+        for (i, quasi) in quasis.iter().enumerate() {
+            let s = quasi.value.cooked.as_ref().map(|c| c.to_string()).unwrap_or_default();
+            let const_idx = ctx.add_constant(Constant::String(s));
+            let str_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(str_reg as u32), const_idx));
+            let idx_const = ctx.add_constant(Constant::Int(i as i32));
+            let idx_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(idx_reg as u32), idx_const));
+            ctx.inst(Inst::new(OpCode::SET_ELEM, Operand::Reg(cooked_temp as u32), Operand::Reg(idx_reg as u32), Operand::Reg(str_reg as u32)));
+        }
+
+        let raw_temp = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::NEW_ARRAY, Operand::Reg(raw_temp as u32), Operand::Imm(quasis.len() as u16), Operand::None));
+        for (i, quasi) in quasis.iter().enumerate() {
+            let raw = quasi.value.raw.to_string();
+            let const_idx = ctx.add_constant(Constant::String(raw));
+            let str_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(str_reg as u32), const_idx));
+            let idx_const = ctx.add_constant(Constant::Int(i as i32));
+            let idx_reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(idx_reg as u32), idx_const));
+            ctx.inst(Inst::new(OpCode::SET_ELEM, Operand::Reg(raw_temp as u32), Operand::Reg(idx_reg as u32), Operand::Reg(str_reg as u32)));
+        }
+
+        let mut expr_temps = Vec::new();
+        for expr in expressions {
+            expr_temps.push(self.emit_expression(expr, ctx)?);
+        }
+
+        let cooked_slot = ctx.alloc_reg();
+        let raw_slot = ctx.alloc_reg();
+        let mut expr_slots = Vec::new();
+        for _ in expressions {
+            expr_slots.push(ctx.alloc_reg());
+        }
+
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(cooked_slot as u32), Operand::Reg(cooked_temp as u32), Operand::None));
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(raw_slot as u32), Operand::Reg(raw_temp as u32), Operand::None));
+        for (slot, temp) in expr_slots.iter().zip(expr_temps.iter()) {
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(*slot as u32), Operand::Reg(*temp as u32), Operand::None));
+        }
+
+        let undef_idx = ctx.add_constant(Constant::Undefined);
+        let undef_reg = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(undef_reg as u32), undef_idx));
+
+        let arg_count = 2 + expressions.len();
+        ctx.inst(Inst::call(
+            Operand::Reg(tag_reg as u32),
+            Operand::Reg(undef_reg as u32),
+            Operand::Reg(cooked_slot as u32),
+            arg_count as u8,
+        ));
+
+        let result_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::None, Operand::None));
+        Ok(result_reg)
+    }
+}

crates/oxide_emit/src/expr/template/template_literal.rs

@@ -0,0 +1,51 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+
+impl Emitter {
+    pub(crate) fn emit_template_literal_expression(
+        &self, tl: &oxide_parser::TemplateLiteral, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let r = ctx.alloc_reg();
+        let quasis = &tl.quasis;
+        let expressions = &tl.expressions;
+        let segment_count = quasis.len() + expressions.len();
+
+        let expr_regs: Vec<u8> = expressions
+            .iter()
+            .map(|e| self.emit_expression(e, ctx))
+            .collect::<Result<Vec<_>, _>>()?;
+
+        let quasi_const_idxs: Vec<u16> = quasis
+            .iter()
+            .map(|q| {
+                let s = q.value.cooked.as_ref().map(|c| c.to_string()).unwrap_or_default();
+                ctx.add_constant(Constant::String(s))
+            })
+            .collect();
+
+        let total_len_hint: usize = quasis
+            .iter()
+            .map(|q| q.value.cooked.as_ref().map(|c| c.len()).unwrap_or(0))
+            .sum();
+
+        let mut parts = Vec::with_capacity(quasi_const_idxs.len() * 2);
+        let mut expr_iter = expr_regs.iter();
+        for const_idx in quasi_const_idxs.iter() {
+            parts.push(*const_idx as u32 & 0x7FFF_FFFF);
+            if let Some(expr_reg) = expr_iter.next() {
+                parts.push(0x8000_0000u32 | (*expr_reg as u32));
+            }
+        }
+
+        ctx.inst(Inst::template_str(
+            Operand::Reg(r as u32),
+            segment_count as u32,
+            total_len_hint as u16,
+            &parts,
+        ));
+
+        Ok(r)
+    }
+}

crates/oxide_emit/src/expr/this.rs

@@ -0,0 +1,14 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+
+impl Emitter {
+    pub(crate) fn emit_this_expression(&self, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let r = ctx.alloc_reg();
+        let src = ctx.static_block_this_reg.unwrap_or(254);
+        let src_op = if src == 254 { Operand::This } else { Operand::Reg(src as u32) };
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(r as u32), src_op, Operand::None));
+        Ok(r)
+    }
+}

crates/oxide_emit/src/lib.rs

@@ -0,0 +1,14 @@
+pub mod class;
+pub mod closure;
+pub mod emit;
+pub mod emit_ctx;
+pub mod expr;
+pub mod prepass;
+pub mod shared;
+pub mod stmt;
+pub mod symbol_table;
+
+pub use emit::{CompileCtx, Emitter, FunctionBodyContext, LabelScope, ParamSpec};
+pub use emit::{is_int_literal, is_side_effect_free};
+pub use oxide_bytecode::module::Constant;
+pub use oxide_parser::{AssignmentOperator, BinaryOperator, UnaryOperator};

crates/oxide_emit/src/prepass.rs

@@ -0,0 +1,342 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::{Expression, Statement, VariableDeclarationKind};
+
+impl Emitter {
+
+    /// builtin slot allocation ahead of the temporary register pool.
+    pub(crate) fn pre_register_builtin_references(&self, stmts: &[Statement], ctx: &mut CompileCtx) {
+        for stmt in stmts {
+            self.pre_scan_builtin_stmt(stmt, ctx);
+        }
+    }
+
+    fn pre_scan_builtin_stmt(&self, stmt: &Statement, ctx: &mut CompileCtx) {
+        match stmt {
+            Statement::ExpressionStatement(es) => self.pre_scan_builtin_expr(&es.expression, ctx),
+            Statement::VariableDeclaration(vd) => {
+                for d in &vd.declarations {
+                    if let Some(init) = &d.init {
+                        self.pre_scan_builtin_expr(init, ctx);
+                    }
+                }
+            }
+            Statement::ReturnStatement(rs) => {
+                if let Some(a) = &rs.argument {
+                    self.pre_scan_builtin_expr(a, ctx);
+                }
+            }
+            Statement::IfStatement(is) => {
+                self.pre_scan_builtin_expr(&is.test, ctx);
+                self.pre_scan_builtin_stmt(&is.consequent, ctx);
+                if let Some(alt) = &is.alternate {
+                    self.pre_scan_builtin_stmt(alt, ctx);
+                }
+            }
+            Statement::WhileStatement(wh) => {
+                self.pre_scan_builtin_expr(&wh.test, ctx);
+                self.pre_scan_builtin_stmt(&wh.body, ctx);
+            }
+            Statement::DoWhileStatement(dw) => {
+                self.pre_scan_builtin_stmt(&dw.body, ctx);
+                self.pre_scan_builtin_expr(&dw.test, ctx);
+            }
+            Statement::ForStatement(fs) => {
+                if let Some(init) = &fs.init {
+                    if let Some(e) = init.as_expression() {
+                        self.pre_scan_builtin_expr(e, ctx);
+                    } else if let oxide_parser::ForStatementInit::VariableDeclaration(decl) = init {
+                        for d in &decl.declarations {
+                            if let Some(init_expr) = &d.init {
+                                self.pre_scan_builtin_expr(init_expr, ctx);
+                            }
+                        }
+                    }
+                }
+                if let Some(t) = &fs.test {
+                    self.pre_scan_builtin_expr(t, ctx);
+                }
+                if let Some(u) = &fs.update {
+                    self.pre_scan_builtin_expr(u, ctx);
+                }
+                self.pre_scan_builtin_stmt(&fs.body, ctx);
+            }
+            Statement::ForInStatement(fi) => {
+                self.pre_scan_builtin_expr(&fi.right, ctx);
+                self.pre_scan_builtin_stmt(&fi.body, ctx);
+            }
+            Statement::ForOfStatement(fo) => {
+                self.pre_scan_builtin_expr(&fo.right, ctx);
+                self.pre_scan_builtin_stmt(&fo.body, ctx);
+            }
+            Statement::SwitchStatement(sw) => {
+                self.pre_scan_builtin_expr(&sw.discriminant, ctx);
+                for case in &sw.cases {
+                    if let Some(test) = &case.test {
+                        self.pre_scan_builtin_expr(test, ctx);
+                    }
+                    for s in &case.consequent {
+                        self.pre_scan_builtin_stmt(s, ctx);
+                    }
+                }
+            }
+            Statement::ThrowStatement(ts) => {
+                self.pre_scan_builtin_expr(&ts.argument, ctx);
+            }
+            Statement::TryStatement(ts) => {
+                for s in &ts.block.body {
+                    self.pre_scan_builtin_stmt(s, ctx);
+                }
+                if let Some(handler) = &ts.handler {
+                    for s in &handler.body.body {
+                        self.pre_scan_builtin_stmt(s, ctx);
+                    }
+                }
+                if let Some(finalizer) = &ts.finalizer {
+                    for s in &finalizer.body {
+                        self.pre_scan_builtin_stmt(s, ctx);
+                    }
+                }
+            }
+            Statement::BlockStatement(bs) => {
+                for s in &bs.body {
+                    self.pre_scan_builtin_stmt(s, ctx);
+                }
+            }
+            Statement::LabeledStatement(ls) => self.pre_scan_builtin_stmt(&ls.body, ctx),
+            Statement::ClassDeclaration(cd) => {
+                if let Some(super_class) = &cd.super_class {
+                    self.pre_scan_builtin_expr(super_class, ctx);
+                }
+            }
+            Statement::FunctionDeclaration(_) | Statement::BreakStatement(_) | Statement::ContinueStatement(_) => {}
+            _ => {}
+        }
+    }
+
+    fn pre_scan_builtin_expr(&self, expr: &Expression, ctx: &mut CompileCtx) {
+        match expr {
+            Expression::Identifier(ident) => {
+                if CompileCtx::is_known_builtin(ident.name.as_str()) {
+                    let _ = ctx.lookup_or_builtin(ident.name.as_str());
+                }
+            }
+            Expression::BinaryExpression(bin) => {
+                self.pre_scan_builtin_expr(&bin.left, ctx);
+                self.pre_scan_builtin_expr(&bin.right, ctx);
+            }
+            Expression::UnaryExpression(un) => {
+                self.pre_scan_builtin_expr(&un.argument, ctx);
+            }
+            Expression::CallExpression(call) => {
+                self.pre_scan_builtin_expr(&call.callee, ctx);
+                for arg in &call.arguments {
+                    if let Some(e) = arg.as_expression() {
+                        self.pre_scan_builtin_expr(e, ctx);
+                    }
+                }
+            }
+            Expression::NewExpression(ne) => {
+                self.pre_scan_builtin_expr(&ne.callee, ctx);
+                for arg in &ne.arguments {
+                    if let Some(e) = arg.as_expression() {
+                        self.pre_scan_builtin_expr(e, ctx);
+                    }
+                }
+            }
+            Expression::LogicalExpression(log) => {
+                self.pre_scan_builtin_expr(&log.left, ctx);
+                self.pre_scan_builtin_expr(&log.right, ctx);
+            }
+            Expression::ConditionalExpression(cond) => {
+                self.pre_scan_builtin_expr(&cond.test, ctx);
+                self.pre_scan_builtin_expr(&cond.consequent, ctx);
+                self.pre_scan_builtin_expr(&cond.alternate, ctx);
+            }
+            Expression::PrivateInExpression(pin) => {
+                self.pre_scan_builtin_expr(&pin.right, ctx);
+            }
+            Expression::SequenceExpression(seq) => {
+                for e in &seq.expressions {
+                    self.pre_scan_builtin_expr(e, ctx);
+                }
+            }
+            Expression::AssignmentExpression(assign) => {
+                if let Some(target) = assign.left.as_simple_assignment_target() {
+                    self.pre_scan_builtin_target(target, ctx);
+                }
+                self.pre_scan_builtin_expr(&assign.right, ctx);
+            }
+            Expression::UpdateExpression(update) => {
+                self.pre_scan_builtin_target(&update.argument, ctx);
+            }
+            Expression::TemplateLiteral(tl) => {
+                for e in &tl.expressions {
+                    self.pre_scan_builtin_expr(e, ctx);
+                }
+            }
+            Expression::TaggedTemplateExpression(tt) => {
+                self.pre_scan_builtin_expr(&tt.tag, ctx);
+                for e in &tt.quasi.expressions {
+                    self.pre_scan_builtin_expr(e, ctx);
+                }
+            }
+            Expression::ObjectExpression(obj) => {
+                for prop in &obj.properties {
+                    if let oxide_parser::ObjectPropertyKind::ObjectProperty(p) = prop {
+                        if p.computed {
+                            self.pre_scan_builtin_expr(p.key.to_expression(), ctx);
+                        }
+                        self.pre_scan_builtin_expr(&p.value, ctx);
+                    }
+                }
+            }
+            Expression::ArrayExpression(arr) => {
+                for e in &arr.elements {
+                    if let Some(e) = e.as_expression() {
+                        self.pre_scan_builtin_expr(e, ctx);
+                    }
+                }
+            }
+            Expression::PrivateFieldExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+            }
+            Expression::StaticMemberExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+            }
+            Expression::ComputedMemberExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+                self.pre_scan_builtin_expr(&member.expression, ctx);
+            }
+            Expression::ChainExpression(chain) => {
+                self.pre_scan_builtin_chain(&chain.expression, ctx);
+            }
+            Expression::ParenthesizedExpression(p) => self.pre_scan_builtin_expr(&p.expression, ctx),
+            Expression::ArrowFunctionExpression(_)
+            | Expression::FunctionExpression(_)
+            | Expression::ClassExpression(_) => {}
+            _ => {}
+        }
+    }
+
+    fn pre_scan_builtin_target(&self, target: &oxide_parser::SimpleAssignmentTarget, ctx: &mut CompileCtx) {
+        match target {
+            oxide_parser::SimpleAssignmentTarget::StaticMemberExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+            }
+            oxide_parser::SimpleAssignmentTarget::ComputedMemberExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+                self.pre_scan_builtin_expr(&member.expression, ctx);
+            }
+            oxide_parser::SimpleAssignmentTarget::PrivateFieldExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+            }
+            _ => {}
+        }
+    }
+
+    fn pre_scan_builtin_chain(&self, element: &oxide_parser::ChainElement, ctx: &mut CompileCtx) {
+        match element {
+            oxide_parser::ChainElement::StaticMemberExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+            }
+            oxide_parser::ChainElement::ComputedMemberExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+                self.pre_scan_builtin_expr(&member.expression, ctx);
+            }
+            oxide_parser::ChainElement::PrivateFieldExpression(member) => {
+                self.pre_scan_builtin_expr(&member.object, ctx);
+            }
+            oxide_parser::ChainElement::CallExpression(call) => {
+                self.pre_scan_builtin_expr(&call.callee, ctx);
+                for arg in &call.arguments {
+                    if let Some(e) = arg.as_expression() {
+                        self.pre_scan_builtin_expr(e, ctx);
+                    }
+                }
+            }
+            _ => {}
+        }
+    }
+
+
+    pub(crate) fn predeclare_function_declarations(&self, statements: &[Statement], ctx: &mut CompileCtx) {
+        for statement in statements {
+            let Statement::FunctionDeclaration(function) = statement else {
+                continue;
+            };
+            let Some(identifier) = &function.id else {
+                continue;
+            };
+            let reg = ctx.alloc_reg();
+            let _ = ctx.declare_initialized(identifier.name.as_str(), reg, VariableDeclarationKind::Var, false);
+        }
+    }
+
+    /// Pre-declare all `var` bindings in this statement list so hoisted function
+    /// declarations emitted earlier can resolve them. Mirrors the removed count
+    /// pass behavior (see fe8bd86): top-level `var` names must be visible while
+    /// compiling function bodies that close over them.
+    pub(crate) fn predeclare_var_declarations(&self, statements: &[Statement], ctx: &mut CompileCtx) {
+        for statement in statements {
+            match statement {
+                Statement::VariableDeclaration(decl) => {
+                    if !matches!(decl.kind, VariableDeclarationKind::Var) {
+                        continue;
+                    }
+                    for d in &decl.declarations {
+                        if let oxide_parser::BindingPattern::BindingIdentifier(bi) = &d.id {
+                            let reg = ctx.alloc_reg();
+                            let _ = ctx.declare_initialized(bi.name.as_str(), reg, VariableDeclarationKind::Var, false);
+                        }
+                    }
+                }
+                Statement::BlockStatement(bs) => self.predeclare_var_declarations(&bs.body, ctx),
+                Statement::IfStatement(is) => {
+                    self.predeclare_var_declarations(std::slice::from_ref(&is.consequent), ctx);
+                    if let Some(alt) = &is.alternate {
+                        self.predeclare_var_declarations(std::slice::from_ref(alt), ctx);
+                    }
+                }
+                Statement::WhileStatement(wh) => {
+                    self.predeclare_var_declarations(std::slice::from_ref(&wh.body), ctx);
+                }
+                Statement::DoWhileStatement(dw) => {
+                    self.predeclare_var_declarations(std::slice::from_ref(&dw.body), ctx);
+                }
+                Statement::ForStatement(fs) => {
+                    if let Some(oxide_parser::ForStatementInit::VariableDeclaration(decl)) = &fs.init {
+                        if matches!(decl.kind, VariableDeclarationKind::Var) {
+                            for d in &decl.declarations {
+                                if let oxide_parser::BindingPattern::BindingIdentifier(bi) = &d.id {
+                                    let reg = ctx.alloc_reg();
+                                    let _ =
+                                        ctx.declare_initialized(bi.name.as_str(), reg, VariableDeclarationKind::Var, false);
+                                }
+                            }
+                        }
+                    }
+                    self.predeclare_var_declarations(std::slice::from_ref(&fs.body), ctx);
+                }
+                Statement::SwitchStatement(sw) => {
+                    for case in &sw.cases {
+                        self.predeclare_var_declarations(&case.consequent, ctx);
+                    }
+                }
+                Statement::TryStatement(ts) => {
+                    self.predeclare_var_declarations(&ts.block.body, ctx);
+                    if let Some(handler) = &ts.handler {
+                        self.predeclare_var_declarations(&handler.body.body, ctx);
+                    }
+                    if let Some(finalizer) = &ts.finalizer {
+                        self.predeclare_var_declarations(&finalizer.body, ctx);
+                    }
+                }
+                Statement::LabeledStatement(ls) => {
+                    self.predeclare_var_declarations(std::slice::from_ref(&ls.body), ctx);
+                }
+                _ => {}
+            }
+        }
+    }
+
+}

crates/oxide_emit/src/shared/binding.rs

@@ -0,0 +1,241 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{
+    ArrayAssignmentTarget, ArrayPattern, AssignmentTarget, AssignmentTargetMaybeDefault, AssignmentTargetProperty,
+    BindingPattern, Expression, ObjectAssignmentTarget, ObjectPattern, VariableDeclarationKind,
+};
+
+impl Emitter {
+    fn emit_default_if_undefined(
+        &self, val_reg: u8, default_expr: &Expression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let undef_reg = self.emit_undefined(ctx);
+        let eq_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::STRICT_EQ, Operand::Reg(eq_reg as u32), Operand::Reg(val_reg as u32), Operand::Reg(undef_reg as u32)));
+        // val != undefined（eq 为 false）→ 跳过默认值
+        let end_label = ctx.next_label_id();
+        ctx.inst(Inst::jmp_if_false(eq_reg, end_label));
+        let default_reg = self.emit_expression(default_expr, ctx)?;
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(val_reg as u32), Operand::Reg(default_reg as u32), Operand::None));
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+        Ok(val_reg)
+    }
+
+    fn emit_bind_target(
+        &self, name: &str, src_reg: u8, kind: VariableDeclarationKind, is_const: bool, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        let target_reg = if matches!(kind, VariableDeclarationKind::Var) {
+            // `var` names are pre-declared (hoisting); reuse the pre-registered slot
+            // instead of allocating a new one so n_registers matches let/const.
+            if let Some(reg) = ctx.scopes.symbols.lookup_any(name) {
+                reg
+            } else {
+                let var_reg = ctx.alloc_reg();
+                ctx.declare(name, var_reg, kind, is_const)?;
+                var_reg
+            }
+        } else {
+            let var_reg = ctx.alloc_reg();
+            ctx.declare(name, var_reg, kind, is_const)?;
+            var_reg
+        };
+        if let Some(&cell_idx) = ctx.captured_bindings.get(name) {
+            ctx.inst(Inst::new(OpCode::MAKE_CELL, Operand::Reg(src_reg as u32), Operand::Imm(cell_idx as u16), Operand::None));
+        } else {
+            ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(target_reg as u32), Operand::Reg(src_reg as u32), Operand::Imm(if is_const { 1 } else { 0 })));
+        }
+        ctx.init_var(name);
+        Ok(())
+    }
+
+    pub(crate) fn emit_assign_target(
+        &self, target: &AssignmentTarget, src_reg: u8, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        match target {
+            AssignmentTarget::AssignmentTargetIdentifier(id) => {
+                let name = id.name.as_str();
+                let var_reg = ctx.lookup_or_global(name);
+                ctx.inst(Inst::new(
+                    OpCode::STORE_VAR,
+                    Operand::Reg(var_reg as u32),
+                    Operand::Reg(src_reg as u32),
+                    Operand::Imm(if ctx.lookup_const_flag(name) { 1 } else { 0 }),
+                ));
+                Ok(())
+            }
+            AssignmentTarget::ArrayAssignmentTarget(ap) => self.emit_array_assignment(ap, src_reg, ctx),
+            AssignmentTarget::ObjectAssignmentTarget(op) => self.emit_object_assignment(op, src_reg, ctx),
+            _ => Err("assignment target not supported".into()),
+        }
+    }
+
+    pub(crate) fn emit_binding_pattern(
+        &self, pattern: &BindingPattern, src_reg: u8, kind: VariableDeclarationKind, is_const: bool,
+        ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        match pattern {
+            BindingPattern::BindingIdentifier(bi) => {
+                self.emit_bind_target(bi.name.as_str(), src_reg, kind, is_const, ctx)
+            }
+            BindingPattern::ArrayPattern(ap) => self.emit_array_binding(ap, src_reg, kind, is_const, ctx),
+            BindingPattern::ObjectPattern(op) => self.emit_object_binding(op, src_reg, kind, is_const, ctx),
+            BindingPattern::AssignmentPattern(ap) => {
+                let val_reg = self.emit_default_if_undefined(src_reg, &ap.right, ctx)?;
+                self.emit_binding_pattern(&ap.left, val_reg, kind, is_const, ctx)
+            }
+        }
+    }
+
+    fn emit_array_binding(
+        &self, ap: &ArrayPattern, src_reg: u8, kind: VariableDeclarationKind, is_const: bool, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        ctx.inst(Inst::new(OpCode::FOR_OF_INIT, Operand::None, Operand::Reg(src_reg as u32), Operand::None));
+        for elem in &ap.elements {
+            let has_reg = ctx.alloc_reg();
+            ctx.inst(Inst::new(OpCode::FOR_OF_DONE, Operand::Reg(has_reg as u32), Operand::None, Operand::None));
+            let val_reg = ctx.alloc_reg();
+            ctx.inst(Inst::new(OpCode::FOR_OF_NEXT, Operand::Reg(val_reg as u32), Operand::None, Operand::None));
+            if let Some(pattern) = elem {
+                self.emit_binding_pattern(pattern, val_reg, kind, is_const, ctx)?;
+            }
+        }
+        if let Some(rest) = &ap.rest {
+            let rest_reg = self.emit_collect_rest_array(ctx)?;
+            self.emit_binding_pattern(&rest.argument, rest_reg, kind, is_const, ctx)?;
+        }
+        ctx.inst(Inst::new(OpCode::FOR_OF_CLOSE, Operand::None, Operand::None, Operand::None));
+        Ok(())
+    }
+
+    fn emit_collect_rest_array(&self, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let rest_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::NEW_ARRAY, Operand::Reg(rest_reg as u32), Operand::None, Operand::None));
+        let idx_reg = ctx.alloc_reg();
+        let zero_idx = ctx.add_constant(Constant::Int(0));
+        ctx.inst(Inst::load_const(Operand::Reg(idx_reg as u32), zero_idx));
+        let loop_start = ctx.next_label_id();
+        let loop_end = ctx.next_label_id();
+        ctx.labels.set_label_pos(loop_start, ctx.insts.len());
+        let has_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::FOR_OF_DONE, Operand::Reg(has_reg as u32), Operand::None, Operand::None));
+        ctx.inst(Inst::jmp_if_false(has_reg, loop_end));
+        let val_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::FOR_OF_NEXT, Operand::Reg(val_reg as u32), Operand::None, Operand::None));
+        ctx.inst(Inst::new(OpCode::SET_ELEM, Operand::Reg(rest_reg as u32), Operand::Reg(idx_reg as u32), Operand::Reg(val_reg as u32)));
+        let tmp_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::INC_PRE, Operand::Reg(idx_reg as u32), Operand::Reg(tmp_reg as u32), Operand::Reg(tmp_reg as u32)));
+        ctx.inst(Inst::jmp(loop_start));
+        ctx.labels.set_label_pos(loop_end, ctx.insts.len());
+        Ok(rest_reg)
+    }
+
+    fn emit_object_binding(
+        &self, op: &ObjectPattern, src_reg: u8, kind: VariableDeclarationKind, is_const: bool, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        let mut excluded = Vec::new();
+        for prop in &op.properties {
+            let (prop_reg, static_key) = self.emit_object_property_read_key(src_reg, &prop.key, prop.computed, ctx)?;
+            if let Some(key) = static_key {
+                excluded.push(key);
+            }
+            self.emit_binding_pattern(&prop.value, prop_reg, kind, is_const, ctx)?;
+        }
+        if let Some(rest) = &op.rest {
+            let rest_reg = ctx.alloc_reg();
+            let excluded_idx = ctx.add_constant(Constant::String(excluded.join("\0")));
+            ctx.inst(Inst::rest_object(Operand::Reg(rest_reg as u32), Operand::Reg(src_reg as u32), excluded_idx as u32));
+            self.emit_binding_pattern(&rest.argument, rest_reg, kind, is_const, ctx)?;
+        }
+        Ok(())
+    }
+
+    fn emit_assignment_maybe_default(
+        &self, target: &AssignmentTargetMaybeDefault, src_reg: u8, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        match target {
+            AssignmentTargetMaybeDefault::AssignmentTargetWithDefault(default) => {
+                let val_reg = self.emit_default_if_undefined(src_reg, &default.init, ctx)?;
+                self.emit_assign_target(&default.binding, val_reg, ctx)
+            }
+            AssignmentTargetMaybeDefault::ArrayAssignmentTarget(ap) => self.emit_array_assignment(ap, src_reg, ctx),
+            AssignmentTargetMaybeDefault::ObjectAssignmentTarget(op) => self.emit_object_assignment(op, src_reg, ctx),
+            AssignmentTargetMaybeDefault::AssignmentTargetIdentifier(id) => {
+                let name = id.name.as_str();
+                let var_reg = ctx.lookup_or_global(name);
+                ctx.inst(Inst::new(
+                    OpCode::STORE_VAR,
+                    Operand::Reg(var_reg as u32),
+                    Operand::Reg(src_reg as u32),
+                    Operand::Imm(if ctx.lookup_const_flag(name) { 1 } else { 0 }),
+                ));
+                Ok(())
+            }
+            _ => Err("assignment target not supported".into()),
+        }
+    }
+
+    pub(crate) fn emit_array_assignment(
+        &self, ap: &ArrayAssignmentTarget, src_reg: u8, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        ctx.inst(Inst::new(OpCode::FOR_OF_INIT, Operand::None, Operand::Reg(src_reg as u32), Operand::None));
+        for elem in &ap.elements {
+            let has_reg = ctx.alloc_reg();
+            ctx.inst(Inst::new(OpCode::FOR_OF_DONE, Operand::Reg(has_reg as u32), Operand::None, Operand::None));
+            let val_reg = ctx.alloc_reg();
+            ctx.inst(Inst::new(OpCode::FOR_OF_NEXT, Operand::Reg(val_reg as u32), Operand::None, Operand::None));
+            if let Some(target) = elem {
+                self.emit_assignment_maybe_default(target, val_reg, ctx)?;
+            }
+        }
+        if let Some(rest) = &ap.rest {
+            let rest_reg = self.emit_collect_rest_array(ctx)?;
+            self.emit_assign_target(&rest.target, rest_reg, ctx)?;
+        }
+        ctx.inst(Inst::new(OpCode::FOR_OF_CLOSE, Operand::None, Operand::None, Operand::None));
+        Ok(())
+    }
+
+    pub(crate) fn emit_object_assignment(
+        &self, op: &ObjectAssignmentTarget, src_reg: u8, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        let mut excluded = Vec::new();
+        for prop in &op.properties {
+            match prop {
+                AssignmentTargetProperty::AssignmentTargetPropertyIdentifier(id) => {
+                    let key = id.binding.name.as_str().to_string();
+                    excluded.push(key.clone());
+                    let mut prop_reg = self.emit_object_property_read(src_reg, &key, ctx);
+                    if let Some(default_expr) = &id.init {
+                        prop_reg = self.emit_default_if_undefined(prop_reg, default_expr, ctx)?;
+                    }
+                    let name = id.binding.name.as_str();
+                    let var_reg = ctx.lookup_or_global(name);
+                    ctx.inst(Inst::new(
+                        OpCode::STORE_VAR,
+                        Operand::Reg(var_reg as u32),
+                        Operand::Reg(prop_reg as u32),
+                        Operand::Imm(if ctx.lookup_const_flag(name) { 1 } else { 0 }),
+                    ));
+                }
+                AssignmentTargetProperty::AssignmentTargetPropertyProperty(prop) => {
+                    let (prop_reg, static_key) =
+                        self.emit_object_property_read_key(src_reg, &prop.name, prop.computed, ctx)?;
+                    if let Some(key) = static_key {
+                        excluded.push(key);
+                    }
+                    self.emit_assignment_maybe_default(&prop.binding, prop_reg, ctx)?;
+                }
+            }
+        }
+        if let Some(rest) = &op.rest {
+            let rest_reg = ctx.alloc_reg();
+            let excluded_idx = ctx.add_constant(Constant::String(excluded.join("\0")));
+            ctx.inst(Inst::rest_object(Operand::Reg(rest_reg as u32), Operand::Reg(src_reg as u32), excluded_idx as u32));
+            self.emit_assign_target(&rest.target, rest_reg, ctx)?;
+        }
+        Ok(())
+    }
+}

crates/oxide_emit/src/shared/chain.rs

@@ -0,0 +1,260 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::{LabelId, Operand};
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{ChainElement, Expression, LogicalOperator, PropertyKey};
+
+impl Emitter {
+    fn emit_optional_guard(&self, reg: u8, short_label: LabelId, ctx: &mut CompileCtx) -> Result<(), String> {
+        let dup_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(dup_reg as u32), Operand::Reg(reg as u32), Operand::None));
+        ctx.inst(Inst::jmp_if_nullish(dup_reg, short_label));
+        Ok(())
+    }
+
+    fn emit_static_member_get_preserve_base(
+        &self, member: &oxide_parser::StaticMemberExpression, short_label: Option<LabelId>, ctx: &mut CompileCtx,
+    ) -> Result<(u8, u8), String> {
+        let obj_reg = self.emit_chainable_expression(&member.object, short_label, ctx)?;
+        if member.optional {
+            if let Some(label) = short_label {
+                self.emit_optional_guard(obj_reg, label, ctx)?;
+            }
+        }
+        let idx = ctx.add_constant(Constant::String(member.property.name.as_str().to_string()));
+        let key_reg = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), idx));
+        let value_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(value_reg as u32), Operand::Reg(obj_reg as u32), Operand::None));
+        ctx.inst(Inst::ic_get(Operand::Reg(value_reg as u32), Operand::Reg(key_reg as u32)));
+        Ok((value_reg, obj_reg))
+    }
+
+    fn emit_computed_member_get_preserve_base(
+        &self, member: &oxide_parser::ComputedMemberExpression, short_label: Option<LabelId>, ctx: &mut CompileCtx,
+    ) -> Result<(u8, u8), String> {
+        let obj_reg = self.emit_chainable_expression(&member.object, short_label, ctx)?;
+        if member.optional {
+            if let Some(label) = short_label {
+                self.emit_optional_guard(obj_reg, label, ctx)?;
+            }
+        }
+        let key_reg = self.emit_expression(&member.expression, ctx)?;
+        let value_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::GET_PROP_DYNAMIC, Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32), Operand::Reg(value_reg as u32)));
+        Ok((value_reg, obj_reg))
+    }
+
+    fn emit_chain_call(
+        &self, call: &oxide_parser::CallExpression, short_label: Option<LabelId>, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        let (callee_reg, this_reg) = match &call.callee {
+            Expression::StaticMemberExpression(member) => {
+                self.emit_static_member_get_preserve_base(member, short_label, ctx)?
+            }
+            Expression::ComputedMemberExpression(member) => {
+                self.emit_computed_member_get_preserve_base(member, short_label, ctx)?
+            }
+            Expression::PrivateFieldExpression(member) => {
+                let obj_reg = self.emit_chainable_expression(&member.object, short_label, ctx)?;
+                if member.optional {
+                    if let Some(label) = short_label {
+                        self.emit_optional_guard(obj_reg, label, ctx)?;
+                    }
+                }
+                let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
+                let callee_reg = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::GET_PRIVATE, Operand::Reg(callee_reg as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+                (callee_reg, obj_reg)
+            }
+            _ => {
+                let callee_reg = self.emit_chainable_expression(&call.callee, short_label, ctx)?;
+                if call.optional {
+                    if let Some(label) = short_label {
+                        self.emit_optional_guard(callee_reg, label, ctx)?;
+                    }
+                }
+                let this_idx = ctx.add_constant(Constant::Undefined);
+                let this_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(this_reg as u32), this_idx));
+                (callee_reg, this_reg)
+            }
+        };
+        if call.optional
+            && matches!(
+                &call.callee,
+                Expression::StaticMemberExpression(_)
+                    | Expression::ComputedMemberExpression(_)
+                    | Expression::PrivateFieldExpression(_)
+            )
+        {
+            if let Some(label) = short_label {
+                self.emit_optional_guard(callee_reg, label, ctx)?;
+            }
+        }
+        let mut arg_regs = Vec::new();
+        for arg in &call.arguments {
+            if let Some(expr) = arg.as_expression() {
+                arg_regs.push(self.emit_expression(expr, ctx)?);
+            }
+        }
+        let first_arg_reg = if arg_regs.is_empty() { 0u8 } else { arg_regs[0] };
+        let op = match &call.callee {
+            Expression::Identifier(ident) if ctx.is_builtin(ident.name.as_str()) => OpCode::CALL_NATIVE,
+            _ => OpCode::CALL,
+        };
+        match op {
+            OpCode::CALL => {
+                ctx.inst(Inst::call(
+                    Operand::Reg(callee_reg as u32),
+                    Operand::Reg(this_reg as u32),
+                    Operand::Reg(first_arg_reg as u32),
+                    arg_regs.len() as u8,
+                ));
+            }
+            OpCode::CALL_NATIVE => {
+                ctx.inst(Inst::call_native(
+                    Operand::Reg(callee_reg as u32),
+                    Operand::Reg(this_reg as u32),
+                    Operand::Reg(first_arg_reg as u32),
+                    arg_regs.len() as u8,
+                ));
+            }
+            _ => unreachable!(),
+        }
+        let result_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::None, Operand::None));
+        Ok(result_reg)
+    }
+
+    fn emit_chainable_expression(
+        &self, expr: &Expression, short_label: Option<LabelId>, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        match expr {
+            Expression::StaticMemberExpression(member) => {
+                let (value_reg, _) = self.emit_static_member_get_preserve_base(member, short_label, ctx)?;
+                Ok(value_reg)
+            }
+            Expression::ComputedMemberExpression(member) => {
+                let (value_reg, _) = self.emit_computed_member_get_preserve_base(member, short_label, ctx)?;
+                Ok(value_reg)
+            }
+            Expression::PrivateFieldExpression(member) => {
+                let obj_reg = self.emit_chainable_expression(&member.object, short_label, ctx)?;
+                if member.optional {
+                    if let Some(label) = short_label {
+                        self.emit_optional_guard(obj_reg, label, ctx)?;
+                    }
+                }
+                let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
+                let value_reg = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::GET_PRIVATE, Operand::Reg(value_reg as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+                Ok(value_reg)
+            }
+            Expression::CallExpression(call) => self.emit_chain_call(call, short_label, ctx),
+            Expression::ChainExpression(chain) => self.emit_chain_element(&chain.expression, short_label, ctx),
+            _ => self.emit_expression(expr, ctx),
+        }
+    }
+
+    pub(crate) fn emit_chain_element(
+        &self, element: &ChainElement, short_label: Option<LabelId>, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        match element {
+            ChainElement::StaticMemberExpression(member) => {
+                let (value_reg, _) = self.emit_static_member_get_preserve_base(member, short_label, ctx)?;
+                Ok(value_reg)
+            }
+            ChainElement::ComputedMemberExpression(member) => {
+                let (value_reg, _) = self.emit_computed_member_get_preserve_base(member, short_label, ctx)?;
+                Ok(value_reg)
+            }
+            ChainElement::PrivateFieldExpression(member) => {
+                let obj_reg = self.emit_chainable_expression(&member.object, short_label, ctx)?;
+                if member.optional {
+                    if let Some(label) = short_label {
+                        self.emit_optional_guard(obj_reg, label, ctx)?;
+                    }
+                }
+                let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
+                let value_reg = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::GET_PRIVATE, Operand::Reg(value_reg as u32), Operand::Reg(obj_reg as u32), Operand::Reg(key_reg as u32)));
+                Ok(value_reg)
+            }
+            ChainElement::CallExpression(call) => self.emit_chain_call(call, short_label, ctx),
+            ChainElement::TSNonNullExpression(_) => Err("TS non-null expressions are not supported in JS mode".into()),
+        }
+    }
+
+    pub(crate) fn emit_logical_assign_test(
+        &self, op: LogicalOperator, test_reg: u8, store_label: LabelId, end_label: LabelId, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        match op {
+            LogicalOperator::And => ctx.inst(Inst::jmp_if_false(test_reg, end_label)),
+            LogicalOperator::Or => ctx.inst(Inst::jmp_if_true(test_reg, end_label)),
+            LogicalOperator::Coalesce => {
+                ctx.inst(Inst::jmp_if_nullish(test_reg, store_label));
+                ctx.inst(Inst::jmp(end_label));
+            }
+        }
+        Ok(())
+    }
+
+    pub(crate) fn emit_object_property_read(&self, src_reg: u8, key: &str, ctx: &mut CompileCtx) -> u8 {
+        let prop_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(prop_reg as u32), Operand::Reg(src_reg as u32), Operand::None));
+        let key_idx = ctx.add_constant(Constant::String(key.to_string()));
+        let key_reg = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), key_idx));
+        ctx.inst(Inst::ic_get(Operand::Reg(prop_reg as u32), Operand::Reg(key_reg as u32)));
+        prop_reg
+    }
+
+    fn emit_property_key_expression(&self, key: &PropertyKey, ctx: &mut CompileCtx) -> Result<u8, String> {
+        match key {
+            PropertyKey::Identifier(ident) => {
+                let name = ident.name.as_str();
+                let var_reg = ctx.lookup_or_builtin(name)?;
+                let key_reg = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(key_reg as u32), Operand::Reg(var_reg as u32), Operand::None));
+                Ok(key_reg)
+            }
+            PropertyKey::StringLiteral(s) => {
+                let key_idx = ctx.add_constant(Constant::String(s.value.to_string()));
+                let key_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), key_idx));
+                Ok(key_reg)
+            }
+            PropertyKey::NumericLiteral(n) => {
+                let key_idx = ctx.add_constant(Constant::Number(n.value));
+                let key_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), key_idx));
+                Ok(key_reg)
+            }
+            PropertyKey::StaticIdentifier(ident) => {
+                let key_idx = ctx.add_constant(Constant::String(ident.name.as_str().to_string()));
+                let key_reg = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(key_reg as u32), key_idx));
+                Ok(key_reg)
+            }
+            _ => Err("computed destructuring key expression not supported".into()),
+        }
+    }
+
+    pub(crate) fn emit_object_property_read_key(
+        &self, src_reg: u8, key: &PropertyKey, computed: bool, ctx: &mut CompileCtx,
+    ) -> Result<(u8, Option<String>), String> {
+        if !computed {
+            let key_name = self.static_property_name(key)?;
+            let prop_reg = self.emit_object_property_read(src_reg, &key_name, ctx);
+            return Ok((prop_reg, Some(key_name)));
+        }
+        let prop_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(prop_reg as u32), Operand::Reg(src_reg as u32), Operand::None));
+        let key_reg = self.emit_property_key_expression(key, ctx)?;
+        let val_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::GET_PROP_DYNAMIC, Operand::Reg(prop_reg as u32), Operand::Reg(key_reg as u32), Operand::Reg(val_reg as u32)));
+        Ok((val_reg, None))
+    }
+}

crates/oxide_emit/src/shared/class_field.rs

@@ -0,0 +1,50 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{Expression, PropertyKey};
+
+impl Emitter {
+    pub(crate) fn emit_public_field_init(
+        &self, target: Operand, key: &PropertyKey, computed: bool, value: Option<&Expression>, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        let key_reg = self.emit_class_key_reg(key, computed, ctx)?;
+        let value_reg = if let Some(expr) = value {
+            self.emit_expression(expr, ctx)?
+        } else {
+            self.emit_undefined(ctx)
+        };
+        if computed {
+            ctx.inst(Inst::new(OpCode::SET_PROP_DYNAMIC, target, Operand::Reg(key_reg as u32), Operand::Reg(value_reg as u32)));
+        } else {
+            ctx.inst(Inst::new(OpCode::SET_PROP, target, Operand::Reg(value_reg as u32), Operand::Reg(key_reg as u32)));
+        }
+        Ok(())
+    }
+
+    pub(crate) fn emit_private_field_init(
+        &self, target: Operand, name: &str, value: Option<&Expression>, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        let key_reg = self.emit_private_id_reg(name, ctx)?;
+        let value_reg = if let Some(expr) = value {
+            self.emit_expression(expr, ctx)?
+        } else {
+            self.emit_undefined(ctx)
+        };
+        ctx.inst(Inst::new(OpCode::INIT_PRIVATE, target, Operand::Reg(value_reg as u32), Operand::Reg(key_reg as u32)));
+        Ok(())
+    }
+
+    pub(crate) fn emit_private_method_init(
+        &self, target: Operand, method: &oxide_parser::MethodDefinition, home_reg: Operand, ctx: &mut CompileCtx,
+    ) -> Result<(), String> {
+        let PropertyKey::PrivateIdentifier(private) = &method.key else {
+            return Err("expected private method key".into());
+        };
+        let name = private.name.as_str();
+        let key_reg = self.emit_private_id_reg(name, ctx)?;
+        let method_reg = self.emit_class_method_function(method, name, home_reg, ctx, &[])?;
+        ctx.inst(Inst::new(OpCode::INIT_PRIVATE, target, Operand::Reg(method_reg as u32), Operand::Reg(key_reg as u32)));
+        Ok(())
+    }
+}

crates/oxide_emit/src/shared/class_key.rs

@@ -0,0 +1,68 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_parser::PropertyKey;
+
+impl Emitter {
+    fn private_name_id(&self, name: &str, ctx: &CompileCtx) -> Result<u32, String> {
+        ctx.scopes
+            .private_name_map
+            .iter()
+            .find_map(|(n, id)| (n == name).then_some(*id))
+            .ok_or_else(|| format!("private name #{name} is not defined"))
+    }
+
+    pub(crate) fn emit_private_id_reg(&self, name: &str, ctx: &mut CompileCtx) -> Result<u8, String> {
+        let id = self.private_name_id(name, ctx)?;
+        let idx = ctx.add_constant(Constant::Int(id as i32));
+        let reg = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(reg as u32), idx));
+        Ok(reg)
+    }
+
+    pub(crate) fn emit_class_key_reg(
+        &self, key: &PropertyKey, computed: bool, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        if !computed {
+            let name = self.class_property_name(key)?;
+            let idx = ctx.add_constant(Constant::String(name));
+            let reg = ctx.alloc_reg();
+            ctx.inst(Inst::load_const(Operand::Reg(reg as u32), idx));
+            return Ok(reg);
+        }
+
+        if matches!(key, PropertyKey::PrivateIdentifier(_)) {
+            return Err("private class elements not yet supported".into());
+        }
+        self.emit_expression(key.to_expression(), ctx)
+    }
+
+    pub(crate) fn static_property_name(&self, key: &PropertyKey) -> Result<String, String> {
+        match key {
+            PropertyKey::StaticIdentifier(ident) => Ok(ident.name.as_str().to_string()),
+            PropertyKey::Identifier(ident) => Ok(ident.name.as_str().to_string()),
+            PropertyKey::StringLiteral(s) => Ok(s.value.to_string()),
+            PropertyKey::NumericLiteral(n) => Ok(n.value.to_string()),
+            _ => Err("computed destructuring keys not yet supported".into()),
+        }
+    }
+
+    pub(crate) fn class_property_name(&self, key: &PropertyKey) -> Result<String, String> {
+        match key {
+            PropertyKey::StaticIdentifier(ident) => Ok(ident.name.as_str().to_string()),
+            PropertyKey::Identifier(ident) => Ok(ident.name.as_str().to_string()),
+            PropertyKey::StringLiteral(s) => Ok(s.value.to_string()),
+            PropertyKey::NumericLiteral(n) => Ok(n.value.to_string()),
+            PropertyKey::PrivateIdentifier(_) => Err("private class elements not yet supported".into()),
+            _ => Err("unsupported class property key type".into()),
+        }
+    }
+
+    pub(crate) fn emit_undefined(&self, ctx: &mut CompileCtx) -> u8 {
+        let idx = ctx.add_constant(Constant::Undefined);
+        let reg = ctx.alloc_reg();
+        ctx.inst(Inst::load_const(Operand::Reg(reg as u32), idx));
+        reg
+    }
+}

crates/oxide_emit/src/shared/mod.rs

@@ -0,0 +1,4 @@
+pub mod binding;
+pub mod chain;
+pub mod class_field;
+pub mod class_key;

crates/oxide_emit/src/stmt/basic/break_continue.rs

@@ -0,0 +1,42 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+
+impl Emitter {
+    pub(crate) fn emit_break_statement(
+        &self, stmt: &oxide_parser::BreakStatement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let break_label = if let Some(label) = &stmt.label {
+            let name = label.name.as_str();
+            let scope = ctx
+                .find_label(name)
+                .ok_or_else(|| format!("SyntaxError: Undefined label '{name}'"))?;
+            scope.break_label
+        } else if let Some(sw_label) = ctx.current_switch() {
+            *sw_label
+        } else {
+            let (bl, _) = ctx.current_loop().ok_or("break outside switch or loop".to_string())?;
+            *bl
+        };
+        ctx.inst(Inst::jmp(break_label));
+        Ok(None)
+    }
+
+    pub(crate) fn emit_continue_statement(
+        &self, stmt: &oxide_parser::ContinueStatement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let continue_label = if let Some(label) = &stmt.label {
+            let name = label.name.as_str();
+            let scope = ctx
+                .find_label(name)
+                .ok_or_else(|| format!("SyntaxError: Undefined label '{name}'"))?;
+            scope.continue_label.ok_or_else(|| {
+                format!("SyntaxError: Illegal continue statement: '{name}' does not denote an iteration statement")
+            })?
+        } else {
+            let (_, cl) = ctx.current_loop().ok_or("continue outside loop".to_string())?;
+            *cl
+        };
+        ctx.inst(Inst::jmp(continue_label));
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/basic/expression.rs

@@ -0,0 +1,15 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Statement;
+
+impl Emitter {
+    fn emit_expression_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::ExpressionStatement(es) = stmt else {
+            return Ok(None);
+        };
+        Ok(Some(self.emit_expression(&es.expression, ctx)?))
+    }
+
+    pub(crate) fn emit_basic_expression(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        self.emit_expression_statement(stmt, ctx)
+    }
+}

crates/oxide_emit/src/stmt/basic/labeled.rs

@@ -0,0 +1,32 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Statement;
+
+impl Emitter {
+    fn is_iteration_statement(stmt: &Statement) -> bool {
+        matches!(
+            stmt,
+            Statement::WhileStatement(_)
+                | Statement::DoWhileStatement(_)
+                | Statement::ForStatement(_)
+                | Statement::ForInStatement(_)
+                | Statement::ForOfStatement(_)
+        )
+    }
+
+    pub(crate) fn emit_labeled_statement(
+        &self, stmt: &oxide_parser::LabeledStatement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let name = stmt.label.name.as_str();
+        if Self::is_iteration_statement(&stmt.body) {
+            ctx.queue_loop_label(name)?;
+            self.emit_statement(&stmt.body, ctx)?;
+        } else {
+            let id = ctx.next_label_id();
+            ctx.push_label_scope(name, id, None)?;
+            self.emit_statement(&stmt.body, ctx)?;
+            ctx.labels.set_label_pos(id, ctx.insts.len());
+            ctx.pop_label_scope();
+        }
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/basic/mod.rs

@@ -0,0 +1,18 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Statement;
+
+mod break_continue;
+mod expression;
+mod labeled;
+mod return_stmt;
+
+impl Emitter {
+    pub(crate) fn emit_basic_domain(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        match stmt {
+            Statement::ExpressionStatement(_) => self.emit_basic_expression(stmt, ctx),
+            Statement::ReturnStatement(_) => self.emit_basic_return(stmt, ctx),
+            Statement::EmptyStatement(_) => Ok(None),
+            _ => Ok(None),
+        }
+    }
+}

crates/oxide_emit/src/stmt/basic/return_stmt.rs

@@ -0,0 +1,27 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::Statement;
+
+impl Emitter {
+    fn emit_return_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::ReturnStatement(ret) = stmt else {
+            return Ok(None);
+        };
+        match &ret.argument {
+            Some(expr) => {
+                let r = self.emit_expression(expr, ctx)?;
+                ctx.inst(Inst::new(OpCode::RETURN, Operand::Reg(r as u32), Operand::None, Operand::None));
+            }
+            None => {
+                ctx.inst(Inst::new(OpCode::RETURN, Operand::None, Operand::None, Operand::None));
+            }
+        }
+        Ok(None)
+    }
+
+    pub(crate) fn emit_basic_return(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        self.emit_return_statement(stmt, ctx)
+    }
+}

crates/oxide_emit/src/stmt/block.rs

@@ -0,0 +1,26 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Statement;
+
+impl Emitter {
+    fn emit_block_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::BlockStatement(block) = stmt else {
+            return Ok(None);
+        };
+        ctx.push_scope();
+        let mut r = None;
+        for s in &block.body {
+            if let Some(rr) = self.emit_statement(s, ctx)? {
+                r = Some(rr);
+            }
+        }
+        ctx.pop_scope();
+        Ok(r)
+    }
+
+    pub(crate) fn emit_block_domain(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        match stmt {
+            Statement::BlockStatement(_) => self.emit_block_statement(stmt, ctx),
+            _ => Ok(None),
+        }
+    }
+}

crates/oxide_emit/src/stmt/control.rs

@@ -0,0 +1,55 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::Statement;
+
+impl Emitter {
+    fn emit_if_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::IfStatement(ifs) = stmt else {
+            return Ok(None);
+        };
+        let else_label = ctx.next_label_id();
+        let end_label = ctx.next_label_id();
+
+        let test_reg = self.emit_expression(&ifs.test, ctx)?;
+
+        ctx.inst(Inst::jmp_if_false(test_reg, else_label));
+
+        let cons_reg = self.emit_statement(&ifs.consequent, ctx)?;
+        let result_reg = ctx.alloc_reg();
+        if let Some(r) = cons_reg {
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(r as u32), Operand::None));
+        } else {
+            let undef_idx = ctx.add_constant(Constant::Undefined);
+            ctx.inst(Inst::load_const(Operand::Reg(result_reg as u32), undef_idx));
+        }
+
+        if ifs.alternate.is_some() {
+            ctx.inst(Inst::jmp(end_label));
+        }
+
+        ctx.labels.set_label_pos(else_label, ctx.insts.len());
+        if let Some(alt) = &ifs.alternate {
+            let alt_reg = self.emit_statement(alt, ctx)?;
+            if let Some(r) = alt_reg {
+                ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(r as u32), Operand::None));
+            } else {
+                let undef_idx = ctx.add_constant(Constant::Undefined);
+                ctx.inst(Inst::load_const(Operand::Reg(result_reg as u32), undef_idx));
+            }
+        }
+
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+
+        Ok(Some(result_reg))
+    }
+
+    pub(crate) fn emit_control_domain(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        match stmt {
+            Statement::IfStatement(_) => self.emit_if_statement(stmt, ctx),
+            _ => Ok(None),
+        }
+    }
+}

crates/oxide_emit/src/stmt/declaration/class_decl.rs

@@ -0,0 +1,30 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{Statement, VariableDeclarationKind};
+
+impl Emitter {
+    pub(crate) fn emit_class_declaration_statement(
+        &self, stmt: &Statement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let Statement::ClassDeclaration(class) = stmt else {
+            return Err("ClassDeclaration without name".into());
+        };
+        let name = class
+            .id
+            .as_ref()
+            .map(|id| id.name.to_string())
+            .ok_or_else(|| "ClassDeclaration without name".to_string())?;
+        let var_reg = ctx.alloc_reg();
+        ctx.declare(&name, var_reg, VariableDeclarationKind::Let, false)?;
+        ctx.init_var(&name);
+        let ctor_reg = self.emit_class(class, ctx)?;
+        if let Some(&cell_idx) = ctx.captured_bindings.get(&name) {
+            ctx.inst(Inst::new(OpCode::MAKE_CELL, Operand::Reg(var_reg as u32), Operand::Imm(cell_idx as u16), Operand::None));
+        } else {
+            ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(var_reg as u32), Operand::Reg(ctor_reg as u32), Operand::None));
+        }
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/declaration/function_decl.rs

@@ -0,0 +1,45 @@
+use crate::{CompileCtx, Emitter, ParamSpec};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::Statement;
+
+impl Emitter {
+    pub(crate) fn emit_function_declaration_statement(
+        &self, stmt: &Statement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let Statement::FunctionDeclaration(fd) = stmt else {
+            return Err("FunctionDeclaration without name".into());
+        };
+        let name = if let Some(id) = &fd.id {
+            id.name.to_string()
+        } else {
+            return Err("FunctionDeclaration without name".into());
+        };
+        let mut param_names = Vec::new();
+        for (idx, param) in fd.params.items.iter().enumerate() {
+            match &param.pattern {
+                oxide_parser::BindingPattern::BindingIdentifier(bi) => {
+                    param_names.push(ParamSpec::Identifier(bi.name.to_string()))
+                }
+                pattern => param_names.push(ParamSpec::Pattern {
+                    synthetic_name: format!("@@param_{idx}"),
+                    pattern,
+                }),
+            }
+        }
+        let body_stmts: &[Statement] = if let Some(body) = &fd.body { &body.statements } else { &[] };
+        let mut sub_module = self.compile_function_body(&param_names, body_stmts, ctx, false, false)?;
+        sub_module.function_name = Some(name.clone());
+        ctx.nested.push(sub_module);
+        let var_reg = ctx.lookup(&name)?;
+        ctx.reserve_reg(var_reg);
+        ctx.inst(Inst::create_closure(Operand::Reg(var_reg as u32), ctx.nested.len() as u16));
+        if let Some(&cell_idx) = ctx.captured_bindings.get(&name) {
+            ctx.inst(Inst::new(OpCode::MAKE_CELL, Operand::Reg(var_reg as u32), Operand::Imm(cell_idx as u16), Operand::None));
+        } else {
+            ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(var_reg as u32), Operand::Reg(var_reg as u32), Operand::None));
+        }
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/declaration/mod.rs

@@ -0,0 +1,17 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Statement;
+
+mod class_decl;
+mod function_decl;
+mod var;
+
+impl Emitter {
+    pub(crate) fn emit_declaration_domain(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        match stmt {
+            Statement::VariableDeclaration(_) => self.emit_variable_declaration_statement(stmt, ctx),
+            Statement::FunctionDeclaration(_) => self.emit_function_declaration_statement(stmt, ctx),
+            Statement::ClassDeclaration(_) => self.emit_class_declaration_statement(stmt, ctx),
+            _ => Ok(None),
+        }
+    }
+}

crates/oxide_emit/src/stmt/declaration/var.rs

@@ -0,0 +1,60 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{BindingPattern, Expression, Statement, VariableDeclarationKind};
+
+impl Emitter {
+    pub(crate) fn emit_variable_declaration_statement(
+        &self, stmt: &Statement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let Statement::VariableDeclaration(decl) = stmt else {
+            return Ok(None);
+        };
+        let mut r = None;
+        for d in &decl.declarations {
+            let is_const = matches!(decl.kind, VariableDeclarationKind::Const);
+            if is_const && d.init.is_none() {
+                return Err("const declaration must have an initializer".into());
+            }
+            if let Some(init) = &d.init {
+                let val_reg = self.emit_expression(init, ctx)?;
+                self.emit_binding_pattern(&d.id, val_reg, decl.kind, is_const, ctx)?;
+                if let BindingPattern::BindingIdentifier(bi) = &d.id {
+                    if matches!(*init, Expression::ArrowFunctionExpression(_)) {
+                        if let Some(sub_mod) = ctx.nested.last_mut() {
+                            sub_mod.function_name = Some(bi.name.to_string());
+                        }
+                    }
+                }
+                r = Some(val_reg);
+            } else {
+                let BindingPattern::BindingIdentifier(bi) = &d.id else {
+                    return Err("destructuring declaration requires an initializer".into());
+                };
+                let idx = ctx.add_constant(Constant::Undefined);
+                let tmp = ctx.alloc_reg();
+                ctx.inst(Inst::load_const(Operand::Reg(tmp as u32), idx));
+                let var_reg = ctx.alloc_reg();
+                let target_reg = if matches!(decl.kind, VariableDeclarationKind::Var) {
+                    match ctx.declare(bi.name.as_str(), var_reg, decl.kind, is_const) {
+                        Ok(()) => var_reg,
+                        Err(_) => ctx.lookup(bi.name.as_str()).unwrap_or(var_reg),
+                    }
+                } else {
+                    ctx.declare(bi.name.as_str(), var_reg, decl.kind, is_const)?;
+                    var_reg
+                };
+                if let Some(&cell_idx) = ctx.captured_bindings.get(bi.name.as_str()) {
+                    ctx.inst(Inst::new(OpCode::MAKE_CELL, Operand::Reg(tmp as u32), Operand::Imm(cell_idx as u16), Operand::None));
+                } else {
+                    ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(target_reg as u32), Operand::Reg(tmp as u32), Operand::None));
+                }
+                ctx.init_var(bi.name.as_str());
+                r = Some(var_reg);
+            }
+        }
+        Ok(r)
+    }
+}

crates/oxide_emit/src/stmt/exception/mod.rs

@@ -0,0 +1,15 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Statement;
+
+mod throw;
+mod try_catch;
+
+impl Emitter {
+    pub(crate) fn emit_exception_domain(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        match stmt {
+            Statement::ThrowStatement(_) => self.emit_throw_statement(stmt, ctx),
+            Statement::TryStatement(_) => self.emit_try_statement(stmt, ctx),
+            _ => Ok(None),
+        }
+    }
+}

crates/oxide_emit/src/stmt/exception/throw.rs

@@ -0,0 +1,16 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::Statement;
+
+impl Emitter {
+    pub(crate) fn emit_throw_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::ThrowStatement(ts) = stmt else {
+            return Ok(None);
+        };
+        let exc_reg = self.emit_expression(&ts.argument, ctx)?;
+        ctx.inst(Inst::new(OpCode::THROW, Operand::Reg(exc_reg as u32), Operand::None, Operand::None));
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/exception/try_catch.rs

@@ -0,0 +1,72 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{Statement, VariableDeclarationKind};
+
+impl Emitter {
+    pub(crate) fn emit_try_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::TryStatement(ts) = stmt else {
+            return Ok(None);
+        };
+        let catch_label = ctx.next_label_id();
+        let finally_label = ctx.next_label_id();
+        let try_end_label = ctx.next_label_id();
+        let has_catch = ts.handler.is_some();
+        let has_finally = ts.finalizer.is_some();
+        let result_reg = ctx.alloc_reg();
+        if has_finally {
+            ctx.inst(Inst::try_finally_begin(finally_label));
+        }
+        if has_catch {
+            ctx.inst(Inst::try_begin(catch_label));
+        }
+        let mut last_try_result: Option<u8> = None;
+        for s in &ts.block.body {
+            if let Some(r) = self.emit_statement(s, ctx)? {
+                last_try_result = Some(r);
+            }
+        }
+        ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(last_try_result.unwrap_or(result_reg) as u32), Operand::None));
+        if has_catch {
+            ctx.inst(Inst::new(OpCode::TRY_END, Operand::None, Operand::None, Operand::None));
+        }
+        let jmp_needed = has_catch || has_finally;
+        if jmp_needed {
+            let target = if has_finally { finally_label } else { try_end_label };
+            ctx.inst(Inst::jmp(target));
+        }
+        ctx.labels.set_label_pos(catch_label, ctx.insts.len());
+        if let Some(catch) = &ts.handler {
+            ctx.push_scope();
+            if let Some(param) = &catch.param {
+                let catch_reg = ctx.alloc_reg();
+                if let oxide_parser::BindingPattern::BindingIdentifier(bi) = &param.pattern {
+                    ctx.declare_initialized(bi.name.as_str(), catch_reg, VariableDeclarationKind::Let, false)?;
+                    ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(catch_reg as u32), Operand::None, Operand::None));
+                }
+            }
+            let mut last_catch_result: Option<u8> = None;
+            for s in &catch.body.body {
+                if let Some(r) = self.emit_statement(s, ctx)? {
+                    last_catch_result = Some(r);
+                }
+            }
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(last_catch_result.unwrap_or(result_reg) as u32), Operand::None));
+            ctx.pop_scope();
+        }
+        if has_finally {
+            ctx.labels.set_label_pos(finally_label, ctx.insts.len());
+            let mut last_finally_result: Option<u8> = None;
+            for s in &ts.finalizer.as_ref().unwrap().body {
+                if let Some(r) = self.emit_statement(s, ctx)? {
+                    last_finally_result = Some(r);
+                }
+            }
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg as u32), Operand::Reg(last_finally_result.unwrap_or(result_reg) as u32), Operand::None));
+            ctx.inst(Inst::new(OpCode::TRY_FINALLY_END, Operand::None, Operand::None, Operand::None));
+        }
+        ctx.labels.set_label_pos(try_end_label, ctx.insts.len());
+        Ok(Some(result_reg))
+    }
+}

crates/oxide_emit/src/stmt/iteration/do_while.rs

@@ -0,0 +1,23 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_parser::Statement;
+
+impl Emitter {
+    pub(crate) fn emit_do_while_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::DoWhileStatement(dw) = stmt else {
+            return Ok(None);
+        };
+        let start_label = ctx.next_label_id();
+        let end_label = ctx.next_label_id();
+        ctx.labels.set_label_pos(start_label, ctx.insts.len());
+        ctx.push_loop(end_label, start_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, start_label);
+        self.emit_statement(&dw.body, ctx)?;
+        let test_reg = self.emit_expression(&dw.test, ctx)?;
+        ctx.inst(Inst::jmp_if_true(test_reg, start_label));
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+        ctx.pop_label_scopes(n_labeled);
+        ctx.pop_loop();
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/iteration/for_.rs

@@ -0,0 +1,63 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::module::Constant;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{BindingPattern, ForStatementInit, Statement, VariableDeclarationKind};
+
+impl Emitter {
+    pub(crate) fn emit_for_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::ForStatement(fr) = stmt else {
+            return Ok(None);
+        };
+        let start_label = ctx.next_label_id();
+        let update_label = ctx.next_label_id();
+        let end_label = ctx.next_label_id();
+        ctx.push_loop(end_label, update_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, update_label);
+        if let Some(init) = &fr.init {
+            if let Some(expr) = init.as_expression() {
+                self.emit_expression(expr, ctx)?;
+            } else if let ForStatementInit::VariableDeclaration(decl) = init {
+                for d in &decl.declarations {
+                    let is_const = matches!(decl.kind, VariableDeclarationKind::Const);
+                    if let Some(init_expr) = &d.init {
+                        let val_reg = self.emit_expression(init_expr, ctx)?;
+                        self.emit_binding_pattern(&d.id, val_reg, decl.kind, is_const, ctx)?;
+                    } else if let BindingPattern::BindingIdentifier(bi) = &d.id {
+                        let idx = ctx.add_constant(Constant::Undefined);
+                        let tmp = ctx.alloc_reg();
+                        ctx.inst(Inst::load_const(Operand::Reg(tmp as u32), idx));
+                        let var_reg = ctx.alloc_reg();
+                        let target_reg = if matches!(decl.kind, VariableDeclarationKind::Var) {
+                            match ctx.declare(bi.name.as_str(), var_reg, decl.kind, is_const) {
+                                Ok(()) => var_reg,
+                                Err(_) => ctx.lookup(bi.name.as_str()).unwrap_or(var_reg),
+                            }
+                        } else {
+                            ctx.declare(bi.name.as_str(), var_reg, decl.kind, is_const)?;
+                            var_reg
+                        };
+                        ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(target_reg as u32), Operand::Reg(tmp as u32), Operand::None));
+                        ctx.init_var(bi.name.as_str());
+                    }
+                }
+            }
+        }
+        ctx.labels.set_label_pos(start_label, ctx.insts.len());
+        if let Some(test) = &fr.test {
+            let test_reg = self.emit_expression(test, ctx)?;
+            ctx.inst(Inst::jmp_if_false(test_reg, end_label));
+        }
+        self.emit_statement(&fr.body, ctx)?;
+        ctx.labels.set_label_pos(update_label, ctx.insts.len());
+        if let Some(update) = &fr.update {
+            self.emit_expression(update, ctx)?;
+        }
+        ctx.inst(Inst::jmp(start_label));
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+        ctx.pop_label_scopes(n_labeled);
+        ctx.pop_loop();
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/iteration/for_in.rs

@@ -0,0 +1,56 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{ForStatementLeft, Statement, VariableDeclarationKind};
+
+impl Emitter {
+    pub(crate) fn emit_for_in_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::ForInStatement(fi) = stmt else {
+            return Ok(None);
+        };
+        let start_label = ctx.next_label_id();
+        let end_label = ctx.next_label_id();
+        let obj_reg = self.emit_expression(&fi.right, ctx)?;
+        ctx.inst(Inst::new(OpCode::FOR_IN_INIT, Operand::None, Operand::Reg(obj_reg as u32), Operand::None));
+        ctx.labels.set_label_pos(start_label, ctx.insts.len());
+        ctx.push_loop(end_label, start_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, start_label);
+        let done_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::FOR_IN_DONE, Operand::Reg(done_reg as u32), Operand::None, Operand::None));
+        // done=true 表示迭代结束：done=false 时跳过 end jmp 继续迭代
+        let continue_label = ctx.next_label_id();
+        ctx.inst(Inst::jmp_if_false(done_reg, continue_label));
+        ctx.inst(Inst::jmp(end_label));
+        ctx.labels.set_label_pos(continue_label, ctx.insts.len());
+        let key_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::FOR_IN_NEXT, Operand::Reg(key_reg as u32), Operand::None, Operand::None));
+        match &fi.left {
+            ForStatementLeft::VariableDeclaration(decl) => {
+                for d in &decl.declarations {
+                    let name = match &d.id {
+                        oxide_parser::BindingPattern::BindingIdentifier(bi) => bi.name.as_str(),
+                        _ => return Err("destructuring not supported".into()),
+                    };
+                    let var_reg = ctx.alloc_reg();
+                    ctx.declare(name, var_reg, decl.kind, matches!(decl.kind, VariableDeclarationKind::Const))?;
+                    ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(var_reg as u32), Operand::Reg(key_reg as u32), Operand::None));
+                    ctx.init_var(name);
+                }
+            }
+            ForStatementLeft::AssignmentTargetIdentifier(id_ref) => {
+                let name = id_ref.name.as_str();
+                let var_reg = ctx.lookup_or_global(name);
+                ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(var_reg as u32), Operand::Reg(key_reg as u32), Operand::None));
+            }
+            _ => return Err("unsupported for-in left-hand side".into()),
+        }
+        self.emit_statement(&fi.body, ctx)?;
+        ctx.inst(Inst::jmp(start_label));
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+        ctx.inst(Inst::new(OpCode::FOR_IN_CLEANUP, Operand::None, Operand::None, Operand::None));
+        ctx.pop_label_scopes(n_labeled);
+        ctx.pop_loop();
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/iteration/for_of.rs

@@ -0,0 +1,51 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::{ForStatementLeft, Statement};
+
+impl Emitter {
+    pub(crate) fn emit_for_of_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::ForOfStatement(fo) = stmt else {
+            return Ok(None);
+        };
+        let start_label = ctx.next_label_id();
+        let end_label = ctx.next_label_id();
+        let iter_src_reg = self.emit_expression(&fo.right, ctx)?;
+        ctx.inst(Inst::new(OpCode::FOR_OF_INIT, Operand::None, Operand::Reg(iter_src_reg as u32), Operand::None));
+        ctx.labels.set_label_pos(start_label, ctx.insts.len());
+        ctx.push_loop(end_label, start_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, start_label);
+        let has_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::FOR_OF_DONE, Operand::Reg(has_reg as u32), Operand::None, Operand::None));
+        ctx.inst(Inst::jmp_if_false(has_reg, end_label));
+        let val_reg = ctx.alloc_reg();
+        ctx.inst(Inst::new(OpCode::FOR_OF_NEXT, Operand::Reg(val_reg as u32), Operand::None, Operand::None));
+        match &fo.left {
+            ForStatementLeft::VariableDeclaration(decl) => {
+                for d in &decl.declarations {
+                    self.emit_binding_pattern(&d.id, val_reg, decl.kind, false, ctx)?;
+                }
+            }
+            ForStatementLeft::AssignmentTargetIdentifier(id_ref) => {
+                let name = id_ref.name.as_str();
+                let var_reg = ctx.lookup_or_global(name);
+                ctx.inst(Inst::new(OpCode::STORE_VAR, Operand::Reg(var_reg as u32), Operand::Reg(val_reg as u32), Operand::None));
+            }
+            ForStatementLeft::ArrayAssignmentTarget(ap) => {
+                self.emit_array_assignment(ap, val_reg, ctx)?;
+            }
+            ForStatementLeft::ObjectAssignmentTarget(op) => {
+                self.emit_object_assignment(op, val_reg, ctx)?;
+            }
+            _ => return Err("unsupported for-of left-hand side".into()),
+        }
+        self.emit_statement(&fo.body, ctx)?;
+        ctx.inst(Inst::jmp(start_label));
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+        ctx.inst(Inst::new(OpCode::FOR_OF_CLOSE, Operand::None, Operand::None, Operand::None));
+        ctx.pop_label_scopes(n_labeled);
+        ctx.pop_loop();
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/iteration/mod.rs

@@ -0,0 +1,21 @@
+use crate::{CompileCtx, Emitter};
+use oxide_parser::Statement;
+
+mod do_while;
+mod for_;
+mod for_in;
+mod for_of;
+mod while_loop;
+
+impl Emitter {
+    pub(crate) fn emit_iteration_domain(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        match stmt {
+            Statement::WhileStatement(_) => self.emit_while_statement(stmt, ctx),
+            Statement::DoWhileStatement(_) => self.emit_do_while_statement(stmt, ctx),
+            Statement::ForStatement(_) => self.emit_for_statement(stmt, ctx),
+            Statement::ForInStatement(_) => self.emit_for_in_statement(stmt, ctx),
+            Statement::ForOfStatement(_) => self.emit_for_of_statement(stmt, ctx),
+            _ => Ok(None),
+        }
+    }
+}

crates/oxide_emit/src/stmt/iteration/while_loop.rs

@@ -0,0 +1,24 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_parser::Statement;
+
+impl Emitter {
+    pub(crate) fn emit_while_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::WhileStatement(wh) = stmt else {
+            return Ok(None);
+        };
+        let start_label = ctx.next_label_id();
+        let end_label = ctx.next_label_id();
+        ctx.labels.set_label_pos(start_label, ctx.insts.len());
+        ctx.push_loop(end_label, start_label);
+        let n_labeled = ctx.take_pending_loop_labels(end_label, start_label);
+        let test_reg = self.emit_expression(&wh.test, ctx)?;
+        ctx.inst(Inst::jmp_if_false(test_reg, end_label));
+        self.emit_statement(&wh.body, ctx)?;
+        ctx.inst(Inst::jmp(start_label));
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+        ctx.pop_label_scopes(n_labeled);
+        ctx.pop_loop();
+        Ok(None)
+    }
+}

crates/oxide_emit/src/stmt/mod.rs

@@ -0,0 +1,7 @@
+pub mod basic;
+pub mod block;
+pub mod control;
+pub mod declaration;
+pub mod exception;
+pub mod iteration;
+pub mod switch;

crates/oxide_emit/src/stmt/switch.rs

@@ -0,0 +1,51 @@
+use crate::{CompileCtx, Emitter};
+use oxide_ir::inst::Inst;
+use oxide_ir::operand::Operand;
+use oxide_bytecode::opcode::OpCode;
+use oxide_parser::Statement;
+
+impl Emitter {
+    fn emit_switch_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        let Statement::SwitchStatement(sw) = stmt else {
+            return Ok(None);
+        };
+        let end_label = ctx.next_label_id();
+        ctx.push_switch(end_label);
+        let disc_reg = self.emit_expression(&sw.discriminant, ctx)?;
+        let compare_reg_checkpoint = ctx.reg_checkpoint();
+        let cases = &sw.cases;
+        let mut case_labels = Vec::with_capacity(cases.len());
+        for case in cases.iter() {
+            let case_label = ctx.next_label_id();
+            case_labels.push(case_label);
+            if let Some(test) = &case.test {
+                let test_reg = self.emit_expression(test, ctx)?;
+                let eq_reg = ctx.alloc_reg();
+                ctx.inst(Inst::new(OpCode::EQ, Operand::Reg(eq_reg as u32), Operand::Reg(disc_reg as u32), Operand::Reg(test_reg as u32)));
+                ctx.inst(Inst::jmp_if_true(eq_reg, case_label));
+                ctx.restore_reg_checkpoint(compare_reg_checkpoint);
+            }
+        }
+        let has_default = cases.iter().any(|c| c.test.is_none());
+        if !has_default {
+            ctx.inst(Inst::jmp(end_label));
+        }
+        for (case_idx, case) in cases.iter().enumerate() {
+            let case_label = case_labels[case_idx];
+            ctx.labels.set_label_pos(case_label, ctx.insts.len());
+            for s in &case.consequent {
+                self.emit_statement(s, ctx)?;
+            }
+        }
+        ctx.labels.set_label_pos(end_label, ctx.insts.len());
+        ctx.pop_switch();
+        Ok(None)
+    }
+
+    pub(crate) fn emit_switch_domain(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
+        match stmt {
+            Statement::SwitchStatement(_) => self.emit_switch_statement(stmt, ctx),
+            _ => Ok(None),
+        }
+    }
+}

crates/oxide_emit/src/symbol_table.rs

@@ -0,0 +1,314 @@
+use std::collections::HashMap;
+
+use oxide_parser::VariableDeclarationKind;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum ScopeKind {
+    FunctionScope,
+    BlockScope,
+}
+
+pub(crate) struct Scope {
+    pub(crate) bindings: HashMap<String, Binding>,
+    pub(crate) kind: ScopeKind,
+}
+
+pub(crate) struct Binding {
+    pub(crate) reg: u8,
+    pub(crate) initialized: bool,
+    pub(crate) is_const: bool,
+}
+
+pub struct SymbolTable {
+    pub(crate) scopes: Vec<Scope>,
+}
+
+impl Default for SymbolTable {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl SymbolTable {
+    pub fn new() -> Self {
+        Self {
+            scopes: vec![Scope {
+                bindings: HashMap::new(),
+                kind: ScopeKind::FunctionScope,
+            }],
+        }
+    }
+
+    pub fn push_scope(&mut self) {
+        self.scopes.push(Scope {
+            bindings: HashMap::new(),
+            kind: ScopeKind::BlockScope,
+        });
+    }
+
+    pub(crate) fn push_scope_with_kind(&mut self, kind: ScopeKind) {
+        self.scopes.push(Scope { bindings: HashMap::new(), kind });
+    }
+
+    pub fn pop_scope(&mut self) {
+        if self.scopes.len() > 1 {
+            self.scopes.pop();
+        }
+    }
+
+    fn find_var_target_scope(&self) -> usize {
+        for (i, scope) in self.scopes.iter().enumerate().rev() {
+            if scope.kind == ScopeKind::FunctionScope {
+                return i;
+            }
+        }
+        0
+    }
+
+    pub fn declare(
+        &mut self, name: &str, reg: u8, kind: VariableDeclarationKind, is_const: bool,
+    ) -> Result<(), String> {
+        let target_idx = if matches!(kind, VariableDeclarationKind::Var) {
+            self.find_var_target_scope()
+        } else {
+            self.scopes.len() - 1
+        };
+
+        let target = &mut self.scopes[target_idx];
+        if target.bindings.contains_key(name) {
+            return Err(format!("Identifier '{name}' has already been declared"));
+        }
+        target.bindings.insert(
+            name.to_string(),
+            Binding {
+                reg,
+                initialized: false,
+                is_const: matches!(kind, VariableDeclarationKind::Const) || is_const,
+            },
+        );
+        Ok(())
+    }
+
+    pub fn lookup(&self, name: &str) -> Result<u8, String> {
+        for scope in self.scopes.iter().rev() {
+            if let Some(b) = scope.bindings.get(name) {
+                if b.initialized {
+                    return Ok(b.reg);
+                }
+                return Err(format!("Cannot access '{name}' before initialization"));
+            }
+        }
+        Err(format!("Identifier '{name}' is not defined"))
+    }
+
+    pub(crate) fn lookup_any(&self, name: &str) -> Option<u8> {
+        self.scopes
+            .iter()
+            .rev()
+            .find_map(|scope| scope.bindings.get(name).map(|binding| binding.reg))
+    }
+
+    pub(crate) fn lookup_any_binding(&self, name: &str) -> Option<(&Binding, usize)> {
+        for (i, scope) in self.scopes.iter().enumerate().rev() {
+            if let Some(b) = scope.bindings.get(name) {
+                return Some((b, i));
+            }
+        }
+        None
+    }
+
+    pub fn lookup_or_global(&mut self, name: &str, reg_for_new: u8) -> u8 {
+        for scope in self.scopes.iter().rev() {
+            if let Some(b) = scope.bindings.get(name) {
+                return b.reg;
+            }
+        }
+        self.scopes[0].bindings.insert(
+            name.to_string(),
+            Binding {
+                reg: reg_for_new,
+                initialized: true,
+                is_const: false,
+            },
+        );
+        reg_for_new
+    }
+
+    pub fn lookup_is_const(&self, name: &str) -> bool {
+        for scope in self.scopes.iter().rev() {
+            if let Some(b) = scope.bindings.get(name) {
+                if b.initialized {
+                    return b.is_const;
+                }
+                return false;
+            }
+        }
+        false
+    }
+
+    pub fn declare_initialized(
+        &mut self, name: &str, reg: u8, kind: VariableDeclarationKind, is_const: bool,
+    ) -> Result<(), String> {
+        let target_idx = if matches!(kind, VariableDeclarationKind::Var) {
+            self.find_var_target_scope()
+        } else {
+            self.scopes.len() - 1
+        };
+
+        let target = &mut self.scopes[target_idx];
+        if let Some(b) = target.bindings.get_mut(name) {
+            b.initialized = true;
+            return Ok(());
+        }
+        target.bindings.insert(
+            name.to_string(),
+            Binding {
+                reg,
+                initialized: true,
+                is_const: matches!(kind, VariableDeclarationKind::Const) || is_const,
+            },
+        );
+        Ok(())
+    }
+
+    pub fn pre_register_global(&mut self, name: &str, reg: u8) {
+        self.scopes[0].bindings.entry(name.to_string()).or_insert(Binding {
+            reg,
+            initialized: true,
+            is_const: false,
+        });
+    }
+
+    pub fn init_var(&mut self, name: &str) {
+        for scope in self.scopes.iter_mut().rev() {
+            if let Some(b) = scope.bindings.get_mut(name) {
+                b.initialized = true;
+                return;
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::SymbolTable;
+    use oxide_parser::VariableDeclarationKind;
+
+    fn v() -> VariableDeclarationKind {
+        VariableDeclarationKind::Var
+    }
+    fn l() -> VariableDeclarationKind {
+        VariableDeclarationKind::Let
+    }
+    fn c() -> VariableDeclarationKind {
+        VariableDeclarationKind::Const
+    }
+
+    #[test]
+    fn global_scope_exists() {
+        let st = SymbolTable::new();
+        assert!(st.lookup("x").is_err());
+    }
+
+    #[test]
+    fn declare_and_lookup() {
+        let mut st = SymbolTable::new();
+        st.declare("x", 0, l(), false).unwrap();
+        st.init_var("x");
+        assert_eq!(st.lookup("x").unwrap(), 0);
+    }
+
+    #[test]
+    fn tdz_error() {
+        let mut st = SymbolTable::new();
+        st.declare("x", 0, l(), false).unwrap();
+        assert!(st.lookup("x").unwrap_err().contains("before initialization"));
+    }
+
+    #[test]
+    fn duplicate_declaration_error() {
+        let mut st = SymbolTable::new();
+        st.declare("x", 0, l(), false).unwrap();
+        assert!(st.declare("x", 1, l(), false).is_err());
+    }
+
+    #[test]
+    fn nested_scopes_shadow() {
+        let mut st = SymbolTable::new();
+        st.declare("x", 0, l(), false).unwrap();
+        st.init_var("x");
+        st.push_scope();
+        st.declare("x", 1, l(), false).unwrap();
+        st.init_var("x");
+        assert_eq!(st.lookup("x").unwrap(), 1);
+        st.pop_scope();
+        assert_eq!(st.lookup("x").unwrap(), 0);
+    }
+
+    #[test]
+    fn lookup_or_global_auto_create() {
+        let mut st = SymbolTable::new();
+        let reg = st.lookup_or_global("x", 5);
+        assert_eq!(reg, 5);
+        assert_eq!(st.lookup("x").unwrap(), 5);
+    }
+
+    #[test]
+    fn lookup_or_global_existing() {
+        let mut st = SymbolTable::new();
+        st.declare("x", 3, l(), false).unwrap();
+        st.init_var("x");
+        let reg = st.lookup_or_global("x", 99);
+        assert_eq!(reg, 3);
+    }
+
+    #[test]
+    fn var_hoists_to_function_scope() {
+        let mut st = SymbolTable::new();
+        // Global scope is FunctionScope
+        st.declare("x", 0, l(), false).unwrap();
+        st.init_var("x");
+        // Push a block scope
+        st.push_scope();
+        // var declaration inside block should go to function scope
+        st.declare("y", 1, v(), false).unwrap();
+        st.init_var("y");
+        st.pop_scope();
+        // y should be accessible (it was declared in function scope, not block scope)
+        assert_eq!(st.lookup("y").unwrap(), 1);
+    }
+
+    #[test]
+    fn let_block_scoped() {
+        let mut st = SymbolTable::new();
+        st.declare("x", 0, l(), false).unwrap();
+        st.init_var("x");
+        st.push_scope();
+        st.declare("x", 1, l(), false).unwrap();
+        st.init_var("x");
+        assert_eq!(st.lookup("x").unwrap(), 1);
+        st.pop_scope();
+        assert_eq!(st.lookup("x").unwrap(), 0);
+    }
+
+    #[test]
+    fn const_has_is_const_flag() {
+        let mut st = SymbolTable::new();
+        st.declare("x", 0, c(), false).unwrap();
+        st.init_var("x");
+        let reg = st.lookup("x").unwrap();
+        assert_eq!(reg, 0);
+    }
+
+    #[test]
+    fn var_in_two_blocks_same_function_scope_is_duplicate() {
+        let mut st = SymbolTable::new();
+        st.push_scope();
+        st.declare("y", 1, v(), false).unwrap();
+        st.pop_scope();
+        st.push_scope();
+        // Same function scope, so this should be a duplicate
+        assert!(st.declare("y", 2, v(), false).is_err());
+        st.pop_scope();
+    }
+}