From d8a71bc78e3aef0d96ff8f7f8e4a02c403adc8b7 Mon Sep 17 00:00:00 2001
From: raskad <32105367+raskad@users.noreply.github.com>
Date: Sat, 11 Dec 2021 22:11:39 +0000
Subject: [PATCH] Fix internal vm tests (#1718)

This PR fixes some vm implementation code. All our internal tests should now pass with the vm enabled.

There are only a few (~100) 262 tests left that currently break with the vm, that previously worked.
---
 boa/src/builtins/function/mod.rs           |  13 +-
 boa/src/builtins/iterable/mod.rs           |  45 +-
 boa/src/builtins/json/mod.rs               |   2 +
 boa/src/builtins/regexp/mod.rs             |   4 -
 boa/src/bytecompiler.rs                    | 501 +++++++++++++--------
 boa/src/context.rs                         |  19 +-
 boa/src/environment/lexical_environment.rs |   5 +
 boa/src/exec/tests.rs                      |  23 +-
 boa/src/lib.rs                             |  30 +-
 boa/src/syntax/parser/expression/update.rs |  42 +-
 boa/src/vm/call_frame.rs                   |  25 +-
 boa/src/vm/code_block.rs                   | 157 ++++---
 boa/src/vm/mod.rs                          | 489 +++++++++++++++-----
 boa/src/vm/opcode.rs                       | 246 ++++++++--
 boa_tester/src/exec/js262.rs               |  13 +-
 15 files changed, 1149 insertions(+), 465 deletions(-)

diff --git a/boa/src/builtins/function/mod.rs b/boa/src/builtins/function/mod.rs
index fb18ebb4c3..3381f96b60 100644
--- a/boa/src/builtins/function/mod.rs
+++ b/boa/src/builtins/function/mod.rs
@@ -208,6 +208,7 @@ impl fmt::Debug for Function {
 
 impl Function {
     // Adds the final rest parameters to the Environment as an array
+    #[cfg(not(feature = "vm"))]
     pub(crate) fn add_rest_param(
         param: &FormalParameter,
         index: usize,
@@ -240,6 +241,7 @@ impl Function {
     }
 
     // Adds an argument to the environment
+    #[cfg(not(feature = "vm"))]
     pub(crate) fn add_arguments_to_environment(
         param: &FormalParameter,
         value: JsValue,
@@ -580,7 +582,16 @@ impl BuiltInFunctionObject {
                     .into())
                 }
             }
-
+            #[cfg(feature = "vm")]
+            (Function::VmOrdinary { .. }, Some(name)) if name.is_empty() => {
+                Ok("[Function (anonymous)]".into())
+            }
+            #[cfg(feature = "vm")]
+            (Function::VmOrdinary { .. }, Some(name)) => {
+                Ok(format!("[Function: {}]", &name).into())
+            }
+            #[cfg(feature = "vm")]
+            (Function::VmOrdinary { .. }, None) => Ok("[Function (anonymous)]".into()),
             _ => Ok("TODO".into()),
         }
     }
diff --git a/boa/src/builtins/iterable/mod.rs b/boa/src/builtins/iterable/mod.rs
index 84f54329e9..4df65edaa3 100644
--- a/boa/src/builtins/iterable/mod.rs
+++ b/boa/src/builtins/iterable/mod.rs
@@ -230,30 +230,43 @@ impl IteratorRecord {
         completion: JsResult<JsValue>,
         context: &mut Context,
     ) -> JsResult<JsValue> {
-        let mut inner_result = self.iterator_object.get_field("return", context);
+        // 1. Assert: Type(iteratorRecord.[[Iterator]]) is Object.
+        // 2. Let iterator be iteratorRecord.[[Iterator]].
+        // 3. Let innerResult be GetMethod(iterator, "return").
+        let inner_result = self.iterator_object.get_method("return", context);
+        //let mut inner_result = self.iterator_object.get_field("return", context);
 
-        // 5
+        // 4. If innerResult.[[Type]] is normal, then
         if let Ok(inner_value) = inner_result {
-            // b
-            if inner_value.is_undefined() {
-                return completion;
+            // a. Let return be innerResult.[[Value]].
+            match inner_value {
+                // b. If return is undefined, return Completion(completion).
+                None => return completion,
+                // c. Set innerResult to Call(return, iterator).
+                Some(value) => {
+                    let inner_result = value.call(&self.iterator_object, &[], context);
+
+                    // 5. If completion.[[Type]] is throw, return Completion(completion).
+                    let completion = completion?;
+
+                    // 6. If innerResult.[[Type]] is throw, return Completion(innerResult).
+                    inner_result?;
+
+                    // 7. If Type(innerResult.[[Value]]) is not Object, throw a TypeError exception.
+                    // 8. Return Completion(completion).
+                    return Ok(completion);
+                }
             }
-            // c
-            inner_result = context.call(&inner_value, &self.iterator_object, &[]);
         }
 
-        // 6
+        // 5. If completion.[[Type]] is throw, return Completion(completion).
         let completion = completion?;
 
-        // 7
-        let inner_result = inner_result?;
-
-        // 8
-        if !inner_result.is_object() {
-            return context.throw_type_error("`return` method of iterator didn't return an Object");
-        }
+        // 6. If innerResult.[[Type]] is throw, return Completion(innerResult).
+        inner_result?;
 
-        // 9
+        // 7. If Type(innerResult.[[Value]]) is not Object, throw a TypeError exception.
+        // 8. Return Completion(completion).
         Ok(completion)
     }
 }
diff --git a/boa/src/builtins/json/mod.rs b/boa/src/builtins/json/mod.rs
index 0f3cbc42df..1c68e236fc 100644
--- a/boa/src/builtins/json/mod.rs
+++ b/boa/src/builtins/json/mod.rs
@@ -96,6 +96,8 @@ impl Json {
         // 9. Let unfiltered be completion.[[Value]].
         // 10. Assert: unfiltered is either a String, Number, Boolean, Null, or an Object that is defined by either an ArrayLiteral or an ObjectLiteral.
         let unfiltered = context.eval(script_string.as_bytes())?;
+        #[cfg(feature = "vm")]
+        context.vm.pop_frame();
 
         // 11. If IsCallable(reviver) is true, then
         if let Some(obj) = args.get_or_undefined(1).as_callable() {
diff --git a/boa/src/builtins/regexp/mod.rs b/boa/src/builtins/regexp/mod.rs
index 15bdf69c84..0b9c6043f4 100644
--- a/boa/src/builtins/regexp/mod.rs
+++ b/boa/src/builtins/regexp/mod.rs
@@ -38,9 +38,6 @@ pub struct RegExp {
     /// Regex matcher.
     matcher: Regex,
 
-    /// Update last_index, set if global or sticky flags are set.
-    use_last_index: bool,
-
     /// Flag 's' - dot matches newline characters.
     dot_all: bool,
 
@@ -340,7 +337,6 @@ impl RegExp {
 
         let regexp = RegExp {
             matcher,
-            use_last_index: global || sticky,
             dot_all,
             global,
             ignore_case,
diff --git a/boa/src/bytecompiler.rs b/boa/src/bytecompiler.rs
index fe5d83eb2e..1aa6e62dfe 100644
--- a/boa/src/bytecompiler.rs
+++ b/boa/src/bytecompiler.rs
@@ -16,7 +16,7 @@ use crate::{
     vm::{CodeBlock, Opcode},
     JsBigInt, JsString, JsValue,
 };
-use std::collections::HashMap;
+use std::{collections::HashMap, mem::size_of};
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 enum Literal {
@@ -36,6 +36,8 @@ struct JumpControlInfo {
     start_address: u32,
     kind: JumpControlInfoKind,
     breaks: Vec<Label>,
+    try_continues: Vec<Label>,
+    for_of_in_loop: bool,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -58,9 +60,7 @@ pub struct ByteCompiler {
     code_block: CodeBlock,
     literals_map: HashMap<Literal, u32>,
     names_map: HashMap<JsString, u32>,
-    functions_map: HashMap<JsString, u32>,
     jump_info: Vec<JumpControlInfo>,
-    top_level: bool,
 }
 
 impl ByteCompiler {
@@ -73,9 +73,7 @@ impl ByteCompiler {
             code_block: CodeBlock::new(name, 0, strict, false),
             literals_map: HashMap::new(),
             names_map: HashMap::new(),
-            functions_map: HashMap::new(),
             jump_info: Vec::new(),
-            top_level: true,
         }
     }
 
@@ -243,6 +241,24 @@ impl ByteCompiler {
             start_address,
             kind: JumpControlInfoKind::Loop,
             breaks: Vec::new(),
+            try_continues: Vec::new(),
+            for_of_in_loop: false,
+        })
+    }
+
+    #[inline]
+    fn push_loop_control_info_for_of_in_loop(
+        &mut self,
+        label: Option<Box<str>>,
+        start_address: u32,
+    ) {
+        self.jump_info.push(JumpControlInfo {
+            label,
+            start_address,
+            kind: JumpControlInfoKind::Loop,
+            breaks: Vec::new(),
+            try_continues: Vec::new(),
+            for_of_in_loop: true,
         })
     }
 
@@ -264,6 +280,8 @@ impl ByteCompiler {
             start_address,
             kind: JumpControlInfoKind::Switch,
             breaks: Vec::new(),
+            try_continues: Vec::new(),
+            for_of_in_loop: false,
         })
     }
 
@@ -280,36 +298,55 @@ impl ByteCompiler {
 
     #[inline]
     fn push_try_control_info(&mut self) {
-        self.jump_info.push(JumpControlInfo {
-            label: None,
-            start_address: u32::MAX,
-            kind: JumpControlInfoKind::Try,
-            breaks: Vec::new(),
-        })
+        if !self.jump_info.is_empty() {
+            let start_address = self.jump_info.last().unwrap().start_address;
+
+            self.jump_info.push(JumpControlInfo {
+                label: None,
+                start_address,
+                kind: JumpControlInfoKind::Try,
+                breaks: Vec::new(),
+                try_continues: Vec::new(),
+                for_of_in_loop: false,
+            })
+        }
     }
 
     #[inline]
     fn pop_try_control_info(&mut self, finally_start_address: Option<u32>) {
-        let mut info = self.jump_info.pop().unwrap();
+        if !self.jump_info.is_empty() {
+            let mut info = self.jump_info.pop().unwrap();
 
-        assert!(info.kind == JumpControlInfoKind::Try);
+            assert!(info.kind == JumpControlInfoKind::Try);
 
-        if let Some(finally_start_address) = finally_start_address {
             let mut breaks = Vec::with_capacity(info.breaks.len());
-            let finally_end = self.jump_with_custom_opcode(Opcode::FinallyJump);
-            for label in info.breaks {
-                if label.index < finally_start_address {
-                    self.patch_jump_with_target(label, finally_start_address);
-                    breaks.push(finally_end);
-                } else {
-                    breaks.push(label);
+
+            if let Some(finally_start_address) = finally_start_address {
+                for label in info.try_continues {
+                    if label.index < finally_start_address {
+                        self.patch_jump_with_target(label, finally_start_address);
+                    } else {
+                        self.patch_jump_with_target(label, info.start_address)
+                    }
                 }
+
+                for label in info.breaks {
+                    if label.index < finally_start_address {
+                        self.patch_jump_with_target(label, finally_start_address);
+                        let Label { mut index } = label;
+                        index -= size_of::<Opcode>() as u32;
+                        index -= size_of::<u32>() as u32;
+                        breaks.push(Label { index });
+                    } else {
+                        breaks.push(label);
+                    }
+                }
+                if let Some(jump_info) = self.jump_info.last_mut() {
+                    jump_info.breaks.append(&mut breaks);
+                }
+            } else if let Some(jump_info) = self.jump_info.last_mut() {
+                jump_info.breaks.append(&mut info.breaks);
             }
-            if let Some(jump_info) = self.jump_info.last_mut() {
-                jump_info.breaks.append(&mut breaks);
-            }
-        } else if let Some(jump_info) = self.jump_info.last_mut() {
-            jump_info.breaks.append(&mut info.breaks);
         }
     }
 
@@ -475,7 +512,17 @@ impl ByteCompiler {
                     UnaryOp::Plus => Some(Opcode::Pos),
                     UnaryOp::Not => Some(Opcode::LogicalNot),
                     UnaryOp::Tilde => Some(Opcode::BitNot),
-                    UnaryOp::TypeOf => Some(Opcode::TypeOf),
+                    UnaryOp::TypeOf => {
+                        match &unary.target() {
+                            Node::Identifier(identifier) => {
+                                let index = self.get_or_insert_name(identifier.as_ref());
+                                self.emit(Opcode::GetNameOrUndefined, &[index]);
+                            }
+                            expr => self.compile_expr(expr, true),
+                        }
+                        self.emit_opcode(Opcode::TypeOf);
+                        None
+                    }
                     UnaryOp::Void => Some(Opcode::Void),
                 };
 
@@ -545,17 +592,12 @@ impl ByteCompiler {
                             LogOp::And => {
                                 let exit = self.jump_with_custom_opcode(Opcode::LogicalAnd);
                                 self.compile_expr(binary.rhs(), true);
-                                self.emit(Opcode::ToBoolean, &[]);
                                 self.patch_jump(exit);
                             }
                             LogOp::Or => {
-                                self.emit_opcode(Opcode::Dup);
                                 let exit = self.jump_with_custom_opcode(Opcode::LogicalOr);
-                                self.emit_opcode(Opcode::Pop);
                                 self.compile_expr(binary.rhs(), true);
-                                self.emit_opcode(Opcode::Dup);
                                 self.patch_jump(exit);
-                                self.emit_opcode(Opcode::Pop);
                             }
                             LogOp::Coalesce => {
                                 let exit = self.jump_with_custom_opcode(Opcode::Coalesce);
@@ -585,24 +627,25 @@ impl ByteCompiler {
                             AssignOp::BoolAnd => {
                                 let exit = self.jump_with_custom_opcode(Opcode::LogicalAnd);
                                 self.compile_expr(binary.rhs(), true);
-                                self.emit(Opcode::ToBoolean, &[]);
+                                let access = self.compile_access(binary.lhs());
+                                self.access_set(access, None, use_expr);
                                 self.patch_jump(exit);
-
                                 None
                             }
                             AssignOp::BoolOr => {
                                 let exit = self.jump_with_custom_opcode(Opcode::LogicalOr);
                                 self.compile_expr(binary.rhs(), true);
-                                self.emit(Opcode::ToBoolean, &[]);
+                                let access = self.compile_access(binary.lhs());
+                                self.access_set(access, None, use_expr);
                                 self.patch_jump(exit);
-
                                 None
                             }
                             AssignOp::Coalesce => {
                                 let exit = self.jump_with_custom_opcode(Opcode::Coalesce);
                                 self.compile_expr(binary.rhs(), true);
+                                let access = self.compile_access(binary.lhs());
+                                self.access_set(access, None, use_expr);
                                 self.patch_jump(exit);
-
                                 None
                             }
                         };
@@ -610,10 +653,9 @@ impl ByteCompiler {
                         if let Some(opcode) = opcode {
                             self.compile_expr(binary.rhs(), true);
                             self.emit(opcode, &[]);
+                            let access = self.compile_access(binary.lhs());
+                            self.access_set(access, None, use_expr);
                         }
-
-                        let access = self.compile_access(binary.lhs());
-                        self.access_set(access, None, use_expr);
                     }
                     BinOp::Comma => {
                         self.emit(Opcode::Pop, &[]);
@@ -632,115 +674,107 @@ impl ByteCompiler {
                     match property {
                         PropertyDefinition::IdentifierReference(identifier_reference) => {
                             let index = self.get_or_insert_name(identifier_reference);
-                            self.emit(Opcode::SetPropertyByName, &[index]);
+                            self.emit(Opcode::DefineOwnPropertyByName, &[index]);
                         }
-                        PropertyDefinition::Property(name, node) => {
-                            self.compile_stmt(node, true);
-                            self.emit_opcode(Opcode::Swap);
-                            match name {
-                                PropertyName::Literal(name) => {
-                                    let index = self.get_or_insert_name(name);
-                                    self.emit(Opcode::SetPropertyByName, &[index]);
-                                }
-                                PropertyName::Computed(name_node) => {
-                                    self.compile_stmt(name_node, true);
-                                    self.emit_opcode(Opcode::Swap);
-                                    self.emit_opcode(Opcode::SetPropertyByValue);
-                                }
+                        PropertyDefinition::Property(name, node) => match name {
+                            PropertyName::Literal(name) => {
+                                self.compile_stmt(node, true);
+                                self.emit_opcode(Opcode::Swap);
+                                let index = self.get_or_insert_name(name);
+                                self.emit(Opcode::DefineOwnPropertyByName, &[index]);
                             }
-                        }
+                            PropertyName::Computed(name_node) => {
+                                self.compile_stmt(name_node, true);
+                                self.compile_stmt(node, true);
+                                self.emit_opcode(Opcode::DefineOwnPropertyByValue);
+                            }
+                        },
                         PropertyDefinition::MethodDefinition(kind, name, func) => {
                             match kind {
-                                MethodDefinitionKind::Get => {
-                                    self.compile_stmt(&func.clone().into(), true);
-                                    self.emit_opcode(Opcode::Swap);
-                                    match name {
-                                        PropertyName::Literal(name) => {
-                                            let index = self.get_or_insert_name(name);
-                                            self.emit(Opcode::SetPropertyGetterByName, &[index]);
-                                        }
-                                        PropertyName::Computed(name_node) => {
-                                            self.compile_stmt(name_node, true);
-                                            self.emit_opcode(Opcode::Swap);
-                                            self.emit_opcode(Opcode::SetPropertyGetterByValue);
-                                        }
+                                MethodDefinitionKind::Get => match name {
+                                    PropertyName::Literal(name) => {
+                                        self.compile_stmt(&func.clone().into(), true);
+                                        self.emit_opcode(Opcode::Swap);
+                                        let index = self.get_or_insert_name(name);
+                                        self.emit(Opcode::SetPropertyGetterByName, &[index]);
                                     }
-                                }
-                                MethodDefinitionKind::Set => {
-                                    self.compile_stmt(&func.clone().into(), true);
-                                    self.emit_opcode(Opcode::Swap);
-                                    match name {
-                                        PropertyName::Literal(name) => {
-                                            let index = self.get_or_insert_name(name);
-                                            self.emit(Opcode::SetPropertySetterByName, &[index]);
-                                        }
-                                        PropertyName::Computed(name_node) => {
-                                            self.compile_stmt(name_node, true);
-                                            self.emit_opcode(Opcode::Swap);
-                                            self.emit_opcode(Opcode::SetPropertySetterByValue);
-                                        }
+                                    PropertyName::Computed(name_node) => {
+                                        self.compile_stmt(name_node, true);
+                                        self.compile_stmt(&func.clone().into(), true);
+                                        self.emit_opcode(Opcode::SetPropertyGetterByValue);
                                     }
-                                }
-                                MethodDefinitionKind::Ordinary => {
-                                    self.compile_stmt(&func.clone().into(), true);
-                                    self.emit_opcode(Opcode::Swap);
-                                    match name {
-                                        PropertyName::Literal(name) => {
-                                            let index = self.get_or_insert_name(name);
-                                            self.emit(Opcode::SetPropertyByName, &[index]);
-                                        }
-                                        PropertyName::Computed(name_node) => {
-                                            self.compile_stmt(name_node, true);
-                                            self.emit_opcode(Opcode::Swap);
-                                            self.emit_opcode(Opcode::SetPropertyByValue);
-                                        }
+                                },
+                                MethodDefinitionKind::Set => match name {
+                                    PropertyName::Literal(name) => {
+                                        self.compile_stmt(&func.clone().into(), true);
+                                        self.emit_opcode(Opcode::Swap);
+                                        let index = self.get_or_insert_name(name);
+                                        self.emit(Opcode::SetPropertySetterByName, &[index]);
                                     }
-                                }
+                                    PropertyName::Computed(name_node) => {
+                                        self.compile_stmt(name_node, true);
+                                        self.compile_stmt(&func.clone().into(), true);
+                                        self.emit_opcode(Opcode::SetPropertySetterByValue);
+                                    }
+                                },
+                                MethodDefinitionKind::Ordinary => match name {
+                                    PropertyName::Literal(name) => {
+                                        self.compile_stmt(&func.clone().into(), true);
+                                        self.emit_opcode(Opcode::Swap);
+                                        let index = self.get_or_insert_name(name);
+                                        self.emit(Opcode::DefineOwnPropertyByName, &[index]);
+                                    }
+                                    PropertyName::Computed(name_node) => {
+                                        self.compile_stmt(name_node, true);
+                                        self.compile_stmt(&func.clone().into(), true);
+                                        self.emit_opcode(Opcode::DefineOwnPropertyByValue);
+                                    }
+                                },
                                 MethodDefinitionKind::Generator => {
                                     // TODO: Implement generators
-                                    self.emit_opcode(Opcode::PushUndefined);
-                                    self.emit_opcode(Opcode::Swap);
                                     match name {
                                         PropertyName::Literal(name) => {
+                                            self.emit_opcode(Opcode::PushUndefined);
+                                            self.emit_opcode(Opcode::Swap);
                                             let index = self.get_or_insert_name(name);
-                                            self.emit(Opcode::SetPropertyByName, &[index]);
+                                            self.emit(Opcode::DefineOwnPropertyByName, &[index]);
                                         }
                                         PropertyName::Computed(name_node) => {
                                             self.compile_stmt(name_node, true);
-                                            self.emit_opcode(Opcode::Swap);
-                                            self.emit_opcode(Opcode::SetPropertyByValue);
+                                            self.emit_opcode(Opcode::PushUndefined);
+                                            self.emit_opcode(Opcode::DefineOwnPropertyByValue);
                                         }
                                     }
                                 }
                                 MethodDefinitionKind::Async => {
                                     // TODO: Implement async
-                                    self.emit_opcode(Opcode::PushUndefined);
-                                    self.emit_opcode(Opcode::Swap);
                                     match name {
                                         PropertyName::Literal(name) => {
+                                            self.emit_opcode(Opcode::PushUndefined);
+                                            self.emit_opcode(Opcode::Swap);
                                             let index = self.get_or_insert_name(name);
-                                            self.emit(Opcode::SetPropertyByName, &[index])
+                                            self.emit(Opcode::DefineOwnPropertyByName, &[index])
                                         }
                                         PropertyName::Computed(name_node) => {
                                             self.compile_stmt(name_node, true);
-                                            self.emit_opcode(Opcode::Swap);
-                                            self.emit_opcode(Opcode::SetPropertyByValue);
+                                            self.emit_opcode(Opcode::PushUndefined);
+                                            self.emit_opcode(Opcode::DefineOwnPropertyByValue);
                                         }
                                     }
                                 }
                                 MethodDefinitionKind::AsyncGenerator => {
                                     // TODO: Implement async generators
-                                    self.emit_opcode(Opcode::PushUndefined);
-                                    self.emit_opcode(Opcode::Swap);
                                     match name {
                                         PropertyName::Literal(name) => {
+                                            self.emit_opcode(Opcode::PushUndefined);
+                                            self.emit_opcode(Opcode::Swap);
                                             let index = self.get_or_insert_name(name);
-                                            self.emit(Opcode::SetPropertyByName, &[index])
+                                            self.emit(Opcode::DefineOwnPropertyByName, &[index])
                                         }
                                         PropertyName::Computed(name_node) => {
                                             self.compile_stmt(name_node, true);
-                                            self.emit_opcode(Opcode::Swap);
-                                            self.emit_opcode(Opcode::SetPropertyByValue);
+                                            self.emit_opcode(Opcode::PushUndefined);
+                                            self.emit_opcode(Opcode::DefineOwnPropertyByValue);
                                         }
                                     }
                                 }
@@ -765,8 +799,13 @@ impl ByteCompiler {
                 self.access_get(access, use_expr);
             }
             Node::Assign(assign) => {
-                let access = self.compile_access(assign.lhs());
-                self.access_set(access, Some(assign.rhs()), use_expr);
+                // Implement destructing assignments like here: https://tc39.es/ecma262/#sec-destructuring-assignment
+                if let Node::Object(_) = assign.lhs() {
+                    self.emit_opcode(Opcode::PushUndefined);
+                } else {
+                    let access = self.compile_access(assign.lhs());
+                    self.access_set(access, Some(assign.rhs()), use_expr);
+                }
             }
             Node::GetConstField(node) => {
                 let access = Access::ByName { node };
@@ -791,6 +830,7 @@ impl ByteCompiler {
             }
             Node::ArrayDecl(array) => {
                 self.emit_opcode(Opcode::PushNewArray);
+                self.emit_opcode(Opcode::PopOnReturnAdd);
 
                 for element in array.as_ref() {
                     self.compile_expr(element, true);
@@ -802,6 +842,7 @@ impl ByteCompiler {
                     }
                 }
 
+                self.emit_opcode(Opcode::PopOnReturnSub);
                 if !use_expr {
                     self.emit(Opcode::Pop, &[]);
                 }
@@ -815,7 +856,7 @@ impl ByteCompiler {
             Node::Call(_) => self.call(expr, use_expr),
             Node::New(_) => self.call(expr, use_expr),
             Node::TemplateLit(template_literal) => {
-                for element in template_literal.elements().iter().rev() {
+                for element in template_literal.elements() {
                     match element {
                         TemplateElement::String(s) => {
                             self.emit_push_literal(Literal::String(s.as_ref().into()))
@@ -877,16 +918,6 @@ impl ByteCompiler {
                     }
                 }
 
-                for expr in template.exprs().iter().rev() {
-                    self.compile_expr(expr, true);
-                }
-
-                self.emit_opcode(Opcode::PushNewArray);
-                for raw in template.raws() {
-                    self.emit_push_literal(Literal::String(raw.as_ref().into()));
-                    self.emit_opcode(Opcode::PushValueToArray);
-                }
-
                 self.emit_opcode(Opcode::PushNewArray);
                 for cooked in template.cookeds() {
                     if let Some(cooked) = cooked {
@@ -896,11 +927,22 @@ impl ByteCompiler {
                     }
                     self.emit_opcode(Opcode::PushValueToArray);
                 }
-
                 self.emit_opcode(Opcode::Dup);
+
+                self.emit_opcode(Opcode::PushNewArray);
+                for raw in template.raws() {
+                    self.emit_push_literal(Literal::String(raw.as_ref().into()));
+                    self.emit_opcode(Opcode::PushValueToArray);
+                }
+
+                self.emit_opcode(Opcode::Swap);
                 let index = self.get_or_insert_name("raw");
                 self.emit(Opcode::SetPropertyByName, &[index]);
 
+                for expr in template.exprs() {
+                    self.compile_expr(expr, true);
+                }
+
                 self.emit(Opcode::Call, &[(template.exprs().len() + 1) as u32]);
             }
             _ => unreachable!(),
@@ -1064,7 +1106,10 @@ impl ByteCompiler {
                 let early_exit = self.jump_with_custom_opcode(Opcode::ForInLoopInitIterator);
 
                 let start_address = self.next_opcode_location();
-                self.push_loop_control_info(for_in_loop.label().map(Into::into), start_address);
+                self.push_loop_control_info_for_of_in_loop(
+                    for_in_loop.label().map(Into::into),
+                    start_address,
+                );
 
                 self.emit_opcode(Opcode::PushDeclarativeEnvironment);
                 let exit = self.jump_with_custom_opcode(Opcode::ForInLoopNext);
@@ -1077,7 +1122,7 @@ impl ByteCompiler {
                     IterableLoopInitializer::Var(declaration) => match declaration {
                         Declaration::Identifier { ident, .. } => {
                             let index = self.get_or_insert_name(ident.as_ref());
-                            self.emit(Opcode::SetName, &[index]);
+                            self.emit(Opcode::DefInitVar, &[index]);
                         }
                         Declaration::Pattern(pattern) => {
                             self.compile_declaration_pattern(pattern, Opcode::DefInitVar);
@@ -1086,7 +1131,7 @@ impl ByteCompiler {
                     IterableLoopInitializer::Let(declaration) => match declaration {
                         Declaration::Identifier { ident, .. } => {
                             let index = self.get_or_insert_name(ident.as_ref());
-                            self.emit(Opcode::SetName, &[index]);
+                            self.emit(Opcode::DefInitLet, &[index]);
                         }
                         Declaration::Pattern(pattern) => {
                             self.compile_declaration_pattern(pattern, Opcode::DefInitLet);
@@ -1095,7 +1140,7 @@ impl ByteCompiler {
                     IterableLoopInitializer::Const(declaration) => match declaration {
                         Declaration::Identifier { ident, .. } => {
                             let index = self.get_or_insert_name(ident.as_ref());
-                            self.emit(Opcode::SetName, &[index]);
+                            self.emit(Opcode::DefInitConst, &[index]);
                         }
                         Declaration::Pattern(pattern) => {
                             self.compile_declaration_pattern(pattern, Opcode::DefInitConst);
@@ -1108,11 +1153,11 @@ impl ByteCompiler {
 
                 self.emit(Opcode::Jump, &[start_address]);
 
+                self.patch_jump(exit);
                 self.pop_loop_control_info();
-                self.emit_opcode(Opcode::Pop);
-                self.emit_opcode(Opcode::Pop);
+                self.emit_opcode(Opcode::PushFalse);
+                self.emit_opcode(Opcode::IteratorClose);
 
-                self.patch_jump(exit);
                 self.patch_jump(early_exit);
             }
             Node::ForOfLoop(for_of_loop) => {
@@ -1120,7 +1165,10 @@ impl ByteCompiler {
                 self.emit_opcode(Opcode::InitIterator);
 
                 let start_address = self.next_opcode_location();
-                self.push_loop_control_info(for_of_loop.label().map(Into::into), start_address);
+                self.push_loop_control_info_for_of_in_loop(
+                    for_of_loop.label().map(Into::into),
+                    start_address,
+                );
 
                 self.emit_opcode(Opcode::PushDeclarativeEnvironment);
                 let exit = self.jump_with_custom_opcode(Opcode::ForInLoopNext);
@@ -1133,7 +1181,7 @@ impl ByteCompiler {
                     IterableLoopInitializer::Var(declaration) => match declaration {
                         Declaration::Identifier { ident, .. } => {
                             let index = self.get_or_insert_name(ident.as_ref());
-                            self.emit(Opcode::SetName, &[index]);
+                            self.emit(Opcode::DefInitVar, &[index]);
                         }
                         Declaration::Pattern(pattern) => {
                             self.compile_declaration_pattern(pattern, Opcode::DefInitVar);
@@ -1142,7 +1190,7 @@ impl ByteCompiler {
                     IterableLoopInitializer::Let(declaration) => match declaration {
                         Declaration::Identifier { ident, .. } => {
                             let index = self.get_or_insert_name(ident.as_ref());
-                            self.emit(Opcode::SetName, &[index]);
+                            self.emit(Opcode::DefInitLet, &[index]);
                         }
                         Declaration::Pattern(pattern) => {
                             self.compile_declaration_pattern(pattern, Opcode::DefInitLet);
@@ -1151,7 +1199,7 @@ impl ByteCompiler {
                     IterableLoopInitializer::Const(declaration) => match declaration {
                         Declaration::Identifier { ident, .. } => {
                             let index = self.get_or_insert_name(ident.as_ref());
-                            self.emit(Opcode::SetName, &[index]);
+                            self.emit(Opcode::DefInitConst, &[index]);
                         }
                         Declaration::Pattern(pattern) => {
                             self.compile_declaration_pattern(pattern, Opcode::DefInitConst);
@@ -1165,8 +1213,9 @@ impl ByteCompiler {
                 self.emit(Opcode::Jump, &[start_address]);
 
                 self.patch_jump(exit);
-
                 self.pop_loop_control_info();
+                self.emit_opcode(Opcode::PushFalse);
+                self.emit_opcode(Opcode::IteratorClose);
             }
             Node::WhileLoop(while_) => {
                 let start_address = self.next_opcode_location();
@@ -1200,23 +1249,58 @@ impl ByteCompiler {
                 self.patch_jump(exit);
             }
             Node::Continue(node) => {
-                let label = self.jump();
-                let mut items = self
+                if let Some(start_address) = self
                     .jump_info
-                    .iter_mut()
-                    .rev()
-                    .filter(|info| info.kind == JumpControlInfoKind::Loop);
-                let target = if node.label().is_none() {
-                    items.next()
+                    .last()
+                    .filter(|info| info.kind == JumpControlInfoKind::Try)
+                    .map(|info| info.start_address)
+                {
+                    self.emit_opcode(Opcode::TryEnd);
+                    self.emit(Opcode::FinallySetJump, &[start_address]);
+                    let label = self.jump();
+                    self.jump_info.last_mut().unwrap().try_continues.push(label);
                 } else {
-                    items.find(|info| info.label.as_deref() == node.label())
+                    let mut items = self
+                        .jump_info
+                        .iter()
+                        .rev()
+                        .filter(|info| info.kind == JumpControlInfoKind::Loop);
+                    let address = if node.label().is_none() {
+                        items.next().expect("continue target").start_address
+                    } else {
+                        let mut emit_for_of_in_exit = 0;
+                        let mut address_info = None;
+                        for info in items {
+                            if info.label.as_deref() == node.label() {
+                                address_info = Some(info);
+                                break;
+                            }
+                            if info.for_of_in_loop {
+                                emit_for_of_in_exit += 1;
+                            }
+                        }
+                        let address = address_info.expect("continue target").start_address;
+                        for _ in 0..emit_for_of_in_exit {
+                            self.emit_opcode(Opcode::PopEnvironment);
+                            self.emit_opcode(Opcode::PopEnvironment);
+                            self.emit_opcode(Opcode::Pop);
+                            self.emit_opcode(Opcode::Pop);
+                        }
+                        address
+                    };
+                    self.emit(Opcode::Jump, &[address]);
                 }
-                .expect("continue target")
-                .start_address;
-
-                self.patch_jump_with_target(label, target);
             }
             Node::Break(node) => {
+                if self
+                    .jump_info
+                    .last()
+                    .filter(|info| info.kind == JumpControlInfoKind::Try)
+                    .is_some()
+                {
+                    self.emit_opcode(Opcode::TryEnd);
+                    self.emit(Opcode::FinallySetJump, &[u32::MAX]);
+                }
                 let label = self.jump();
                 if node.label().is_none() {
                     self.jump_info.last_mut().unwrap().breaks.push(label);
@@ -1232,7 +1316,7 @@ impl ByteCompiler {
             Node::Block(block) => {
                 self.emit_opcode(Opcode::PushDeclarativeEnvironment);
                 for node in block.items() {
-                    self.compile_stmt(node, false);
+                    self.compile_stmt(node, use_expr);
                 }
                 self.emit_opcode(Opcode::PopEnvironment);
             }
@@ -1279,19 +1363,24 @@ impl ByteCompiler {
             Node::Try(t) => {
                 self.push_try_control_info();
 
-                let try_start = self.jump_with_custom_opcode(Opcode::TryStart);
-
+                let try_start = self.next_opcode_location();
+                self.emit(Opcode::TryStart, &[Self::DUMMY_ADDRESS, 0]);
                 self.emit_opcode(Opcode::PushDeclarativeEnvironment);
                 for node in t.block().items() {
                     self.compile_stmt(node, false);
                 }
                 self.emit_opcode(Opcode::PopEnvironment);
-
                 self.emit_opcode(Opcode::TryEnd);
+
                 let finally = self.jump();
+                self.patch_jump(Label { index: try_start });
 
-                self.patch_jump(try_start);
                 if let Some(catch) = t.catch() {
+                    let catch_start = if t.finally().is_some() {
+                        Some(self.jump_with_custom_opcode(Opcode::CatchStart))
+                    } else {
+                        None
+                    };
                     self.emit_opcode(Opcode::PushDeclarativeEnvironment);
                     if let Some(decl) = catch.parameter() {
                         match decl {
@@ -1300,28 +1389,35 @@ impl ByteCompiler {
                                 self.emit(Opcode::DefInitLet, &[index]);
                             }
                             Declaration::Pattern(pattern) => {
-                                let idents = pattern.idents();
-                                for (i, ident) in idents.iter().enumerate() {
-                                    if i < idents.len() {
-                                        self.emit_opcode(Opcode::Dup);
-                                    }
-                                    let index = self.get_or_insert_name(ident);
-                                    self.emit(Opcode::DefInitLet, &[index]);
-                                }
+                                self.compile_declaration_pattern(pattern, Opcode::DefInitLet);
                             }
                         }
+                    } else {
+                        self.emit_opcode(Opcode::Pop);
                     }
                     for node in catch.block().items() {
-                        self.compile_stmt(node, false);
+                        self.compile_stmt(node, use_expr);
                     }
                     self.emit_opcode(Opcode::PopEnvironment);
-                    self.emit_opcode(Opcode::TryEnd);
+                    if let Some(catch_start) = catch_start {
+                        self.emit_opcode(Opcode::CatchEnd);
+                        self.patch_jump(catch_start);
+                    } else {
+                        self.emit_opcode(Opcode::CatchEnd2);
+                    }
                 }
 
                 self.patch_jump(finally);
+
                 if let Some(finally) = t.finally() {
                     self.emit_opcode(Opcode::FinallyStart);
                     let finally_start_address = self.next_opcode_location();
+                    self.patch_jump_with_target(
+                        Label {
+                            index: try_start + 4,
+                        },
+                        finally_start_address,
+                    );
 
                     for node in finally.items() {
                         self.compile_stmt(node, false);
@@ -1379,8 +1475,9 @@ impl ByteCompiler {
             _ => unreachable!(),
         };
 
+        let strict = body.strict() || self.code_block.strict;
         let length = parameters.len() as u32;
-        let mut code = CodeBlock::new(name.unwrap_or("").into(), length, false, true);
+        let mut code = CodeBlock::new(name.unwrap_or("").into(), length, strict, true);
 
         if let FunctionKind::Arrow = kind {
             code.constructor = false;
@@ -1391,11 +1488,43 @@ impl ByteCompiler {
             code_block: code,
             literals_map: HashMap::new(),
             names_map: HashMap::new(),
-            functions_map: HashMap::new(),
             jump_info: Vec::new(),
-            top_level: false,
         };
 
+        let mut has_rest_parameter = false;
+        let mut has_parameter_expressions = false;
+        for parameter in parameters {
+            has_parameter_expressions = has_parameter_expressions || parameter.init().is_some();
+
+            if parameter.is_rest_param() {
+                has_rest_parameter = true;
+                compiler.emit_opcode(Opcode::RestParameterInit);
+            }
+
+            match parameter.declaration() {
+                Declaration::Identifier { ident, .. } => {
+                    let index = compiler.get_or_insert_name(ident.as_ref());
+                    if let Some(init) = parameter.declaration().init() {
+                        let skip = compiler.jump_with_custom_opcode(Opcode::JumpIfNotUndefined);
+                        compiler.compile_expr(init, true);
+                        compiler.patch_jump(skip);
+                    }
+                    compiler.emit(Opcode::DefInitArg, &[index]);
+                }
+                Declaration::Pattern(pattern) => {
+                    compiler.compile_declaration_pattern(pattern, Opcode::DefInitArg);
+                }
+            }
+        }
+
+        if !has_rest_parameter {
+            compiler.emit_opcode(Opcode::RestParameterPop);
+        }
+
+        if has_parameter_expressions {
+            compiler.emit_opcode(Opcode::PushFunctionEnvironment)
+        }
+
         for node in body.items() {
             compiler.compile_stmt(node, false);
         }
@@ -1416,8 +1545,7 @@ impl ByteCompiler {
         match kind {
             FunctionKind::Declaration => {
                 let index = self.get_or_insert_name(name.unwrap());
-                let access = Access::Variable { index };
-                self.access_set(access, None, false);
+                self.emit(Opcode::DefInitVar, &[index]);
             }
             FunctionKind::Expression | FunctionKind::Arrow => {
                 if !use_expr {
@@ -1463,7 +1591,7 @@ impl ByteCompiler {
             }
         }
 
-        for arg in call.args().iter().rev() {
+        for arg in call.args().iter() {
             self.compile_expr(arg, true);
         }
 
@@ -1523,7 +1651,6 @@ impl ByteCompiler {
 
                             if let Some(init) = default_init {
                                 let skip = self.jump_with_custom_opcode(Opcode::JumpIfNotUndefined);
-                                self.emit_opcode(Opcode::Pop);
                                 self.compile_expr(init, true);
                                 self.patch_jump(skip);
                             }
@@ -1559,11 +1686,8 @@ impl ByteCompiler {
 
                             if let Some(init) = default_init {
                                 let skip = self.jump_with_custom_opcode(Opcode::JumpIfNotUndefined);
-                                self.emit_opcode(Opcode::Pop);
                                 self.compile_expr(init, true);
                                 self.patch_jump(skip);
-                            } else {
-                                self.emit_opcode(Opcode::PushUndefined);
                             }
 
                             self.compile_declaration_pattern(pattern, def);
@@ -1584,15 +1708,23 @@ impl ByteCompiler {
                 self.emit_opcode(Opcode::ValueNotNullOrUndefined);
                 self.emit_opcode(Opcode::InitIterator);
 
-                for binding in pattern.bindings() {
+                for (i, binding) in pattern.bindings().iter().enumerate() {
                     use BindingPatternTypeArray::*;
 
+                    let next = if i == pattern.bindings().len() - 1 {
+                        Opcode::IteratorNextFull
+                    } else {
+                        Opcode::IteratorNext
+                    };
+
                     match binding {
                         // ArrayBindingPattern : [ ]
-                        Empty => {}
+                        Empty => {
+                            self.emit_opcode(Opcode::PushFalse);
+                        }
                         // ArrayBindingPattern : [ Elision ]
                         Elision => {
-                            self.emit_opcode(Opcode::IteratorNext);
+                            self.emit_opcode(next);
                             self.emit_opcode(Opcode::Pop);
                         }
                         // SingleNameBinding : BindingIdentifier Initializer[opt]
@@ -1600,10 +1732,9 @@ impl ByteCompiler {
                             ident,
                             default_init,
                         } => {
-                            self.emit_opcode(Opcode::IteratorNext);
+                            self.emit_opcode(next);
                             if let Some(init) = default_init {
                                 let skip = self.jump_with_custom_opcode(Opcode::JumpIfNotUndefined);
-                                self.emit_opcode(Opcode::Pop);
                                 self.compile_expr(init, true);
                                 self.patch_jump(skip);
                             }
@@ -1613,7 +1744,7 @@ impl ByteCompiler {
                         }
                         // BindingElement : BindingPattern Initializer[opt]
                         BindingPattern { pattern } => {
-                            self.emit_opcode(Opcode::IteratorNext);
+                            self.emit_opcode(next);
                             self.compile_declaration_pattern(pattern, def)
                         }
                         // BindingRestElement : ... BindingIdentifier
@@ -1622,16 +1753,22 @@ impl ByteCompiler {
 
                             let index = self.get_or_insert_name(ident);
                             self.emit(def, &[index]);
+                            self.emit_opcode(Opcode::PushTrue);
                         }
                         // BindingRestElement : ... BindingPattern
                         BindingPatternRest { pattern } => {
                             self.emit_opcode(Opcode::IteratorToArray);
                             self.compile_declaration_pattern(pattern, def);
+                            self.emit_opcode(Opcode::PushTrue);
                         }
                     }
                 }
 
-                self.emit_opcode(Opcode::Pop);
+                if pattern.bindings().is_empty() {
+                    self.emit_opcode(Opcode::PushFalse);
+                }
+
+                self.emit_opcode(Opcode::IteratorClose);
             }
         }
     }
diff --git a/boa/src/context.rs b/boa/src/context.rs
index d39dc4a6ac..ff63fd80d0 100644
--- a/boa/src/context.rs
+++ b/boa/src/context.rs
@@ -28,7 +28,7 @@ use crate::{
 use crate::builtins::console::Console;
 
 #[cfg(feature = "vm")]
-use crate::vm::Vm;
+use crate::vm::{FinallyReturn, Vm};
 
 /// Store a builtin constructor (such as `Object`) and its corresponding prototype.
 #[derive(Debug, Clone)]
@@ -1054,12 +1054,13 @@ impl Context {
             Err(e) => return self.throw_syntax_error(e),
         };
 
-        let mut compiler = crate::bytecompiler::ByteCompiler::new(JsString::new("<main>"), false);
+        let mut compiler = crate::bytecompiler::ByteCompiler::new(
+            JsString::new("<main>"),
+            statement_list.strict(),
+        );
         compiler.compile_statement_list(&statement_list, true);
         let code_block = compiler.finish();
 
-        let environment = self.get_current_environment().clone();
-        let fp = self.vm.stack.len();
         let global_object = self.global_object().into();
 
         self.vm.push_frame(CallFrame {
@@ -1067,11 +1068,13 @@ impl Context {
             code: Gc::new(code_block),
             this: global_object,
             pc: 0,
-            fp,
-            environment,
-            catch: None,
+            catch: Vec::new(),
+            finally_return: FinallyReturn::None,
+            finally_jump: Vec::new(),
+            pop_on_return: 0,
             pop_env_on_return: 0,
-            finally_no_jump: false,
+            param_count: 0,
+            arg_count: 0,
         });
         let result = self.run();
 
diff --git a/boa/src/environment/lexical_environment.rs b/boa/src/environment/lexical_environment.rs
index e011e019b1..f75bac14d2 100644
--- a/boa/src/environment/lexical_environment.rs
+++ b/boa/src/environment/lexical_environment.rs
@@ -93,6 +93,11 @@ impl Context {
             .recursive_get_this_binding(self)
     }
 
+    pub(crate) fn get_global_this_binding(&mut self) -> JsResult<JsValue> {
+        let global = self.realm.global_env.clone();
+        global.get_this_binding(self)
+    }
+
     pub(crate) fn create_mutable_binding(
         &mut self,
         name: &str,
diff --git a/boa/src/exec/tests.rs b/boa/src/exec/tests.rs
index f09297ad72..e8ebf0bef6 100644
--- a/boa/src/exec/tests.rs
+++ b/boa/src/exec/tests.rs
@@ -772,10 +772,13 @@ mod in_operator {
             new a();
         "#;
 
-        check_output(&[TestAction::TestEq(
-            scenario,
-            "Uncaught \"TypeError\": \"a is not a constructor\"",
-        )]);
+        #[cfg(not(feature = "vm"))]
+        let error = "Uncaught \"TypeError\": \"a is not a constructor\"";
+
+        #[cfg(feature = "vm")]
+        let error = "Uncaught \"TypeError\": \"not a constructor\"";
+
+        check_output(&[TestAction::TestEq(scenario, error)]);
     }
 
     #[test]
@@ -1265,11 +1268,17 @@ fn not_a_function() {
         }
     "#;
 
+    #[cfg(not(feature = "vm"))]
+    let error = "\"TypeError: Value is not callable\"";
+
+    #[cfg(feature = "vm")]
+    let error = "\"TypeError: not a callable function\"";
+
     check_output(&[
         TestAction::Execute(init),
-        TestAction::TestEq(scenario1, "\"TypeError: Value is not callable\""),
-        TestAction::TestEq(scenario2, "\"TypeError: Value is not callable\""),
-        TestAction::TestEq(scenario3, "\"TypeError: Value is not callable\""),
+        TestAction::TestEq(scenario1, error),
+        TestAction::TestEq(scenario2, error),
+        TestAction::TestEq(scenario3, error),
     ]);
 }
 
diff --git a/boa/src/lib.rs b/boa/src/lib.rs
index 59c1336cc2..aa00bdea82 100644
--- a/boa/src/lib.rs
+++ b/boa/src/lib.rs
@@ -101,26 +101,20 @@ pub fn parse<T: AsRef<[u8]>>(src: T, strict_mode: bool) -> StdResult<StatementLi
 #[cfg(test)]
 pub(crate) fn forward<T: AsRef<[u8]>>(context: &mut Context, src: T) -> String {
     let src_bytes: &[u8] = src.as_ref();
-
-    // Setup executor
-    let expr = match parse(src_bytes, false) {
-        Ok(res) => res,
-        Err(e) => {
-            return format!(
-                "Uncaught {}",
-                context.construct_syntax_error(e.to_string()).display()
-            );
-        }
-    };
-    expr.run(context).map_or_else(
+    let result = context.eval(src_bytes).map_or_else(
         |e| format!("Uncaught {}", e.display()),
         |v| v.display().to_string(),
-    )
+    );
+
+    #[cfg(feature = "vm")]
+    context.vm.pop_frame();
+
+    result
 }
 
 /// Execute the code using an existing Context.
 /// The str is consumed and the state of the Context is changed
-/// Similar to `forward`, except the current value is returned instad of the string
+/// Similar to `forward`, except the current value is returned instead of the string
 /// If the interpreter fails parsing an error value is returned instead (error object)
 #[allow(clippy::unit_arg, clippy::drop_copy)]
 #[cfg(test)]
@@ -128,10 +122,10 @@ pub(crate) fn forward_val<T: AsRef<[u8]>>(context: &mut Context, src: T) -> JsRe
     let main_timer = BoaProfiler::global().start_event("Main", "Main");
 
     let src_bytes: &[u8] = src.as_ref();
-    // Setup executor
-    let result = parse(src_bytes, false)
-        .map_err(|e| context.construct_syntax_error(e.to_string()))
-        .and_then(|expr| expr.run(context));
+    let result = context.eval(src_bytes);
+
+    #[cfg(feature = "vm")]
+    context.vm.pop_frame();
 
     // The main_timer needs to be dropped before the BoaProfiler is.
     drop(main_timer);
diff --git a/boa/src/syntax/parser/expression/update.rs b/boa/src/syntax/parser/expression/update.rs
index 07454feeae..876296e84e 100644
--- a/boa/src/syntax/parser/expression/update.rs
+++ b/boa/src/syntax/parser/expression/update.rs
@@ -10,7 +10,7 @@ use crate::{
     profiler::BoaProfiler,
     syntax::{
         ast::{node, op::UnaryOp, Node, Punctuator},
-        lexer::TokenKind,
+        lexer::{Error as LexError, TokenKind},
         parser::{
             expression::unary::UnaryExpression, AllowAwait, AllowYield, Cursor, ParseError,
             ParseResult, TokenParser,
@@ -77,14 +77,54 @@ where
         }
 
         let lhs = LeftHandSideExpression::new(self.allow_yield, self.allow_await).parse(cursor)?;
+        let strict = cursor.strict_mode();
         if let Some(tok) = cursor.peek(0)? {
+            let token_start = tok.span().start();
             match tok.kind() {
                 TokenKind::Punctuator(Punctuator::Inc) => {
                     cursor.next()?.expect("Punctuator::Inc token disappeared");
+                    // https://tc39.es/ecma262/#sec-update-expressions-static-semantics-early-errors
+                    let ok = match &lhs {
+                        Node::Identifier(_) if !strict => true,
+                        Node::Identifier(ident)
+                            if !["eval", "arguments"].contains(&ident.as_ref()) =>
+                        {
+                            true
+                        }
+                        Node::GetConstField(_) => true,
+                        Node::GetField(_) => true,
+                        _ => false,
+                    };
+                    if !ok {
+                        return Err(ParseError::lex(LexError::Syntax(
+                            "Invalid left-hand side in assignment".into(),
+                            token_start,
+                        )));
+                    }
+
                     return Ok(node::UnaryOp::new(UnaryOp::IncrementPost, lhs).into());
                 }
                 TokenKind::Punctuator(Punctuator::Dec) => {
                     cursor.next()?.expect("Punctuator::Dec token disappeared");
+                    // https://tc39.es/ecma262/#sec-update-expressions-static-semantics-early-errors
+                    let ok = match &lhs {
+                        Node::Identifier(_) if !strict => true,
+                        Node::Identifier(ident)
+                            if !["eval", "arguments"].contains(&ident.as_ref()) =>
+                        {
+                            true
+                        }
+                        Node::GetConstField(_) => true,
+                        Node::GetField(_) => true,
+                        _ => false,
+                    };
+                    if !ok {
+                        return Err(ParseError::lex(LexError::Syntax(
+                            "Invalid left-hand side in assignment".into(),
+                            token_start,
+                        )));
+                    }
+
                     return Ok(node::UnaryOp::new(UnaryOp::DecrementPost, lhs).into());
                 }
                 _ => {}
diff --git a/boa/src/vm/call_frame.rs b/boa/src/vm/call_frame.rs
index 165caf03d8..edcc726209 100644
--- a/boa/src/vm/call_frame.rs
+++ b/boa/src/vm/call_frame.rs
@@ -2,7 +2,7 @@
 //! This module will provides everything needed to implement the CallFrame
 
 use super::CodeBlock;
-use crate::{environment::lexical_environment::Environment, JsValue};
+use crate::JsValue;
 use gc::Gc;
 
 #[derive(Debug)]
@@ -10,10 +10,25 @@ pub struct CallFrame {
     pub(crate) prev: Option<Box<Self>>,
     pub(crate) code: Gc<CodeBlock>,
     pub(crate) pc: usize,
-    pub(crate) fp: usize,
     pub(crate) this: JsValue,
-    pub(crate) environment: Environment,
-    pub(crate) catch: Option<u32>,
+    pub(crate) catch: Vec<CatchAddresses>,
+    pub(crate) finally_return: FinallyReturn,
+    pub(crate) finally_jump: Vec<Option<u32>>,
+    pub(crate) pop_on_return: usize,
     pub(crate) pop_env_on_return: usize,
-    pub(crate) finally_no_jump: bool,
+    pub(crate) param_count: usize,
+    pub(crate) arg_count: usize,
+}
+
+#[derive(Debug)]
+pub(crate) struct CatchAddresses {
+    pub(crate) next: u32,
+    pub(crate) finally: Option<u32>,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub(crate) enum FinallyReturn {
+    None,
+    Ok,
+    Err,
 }
diff --git a/boa/src/vm/code_block.rs b/boa/src/vm/code_block.rs
index 9a2c1169cf..9cca9153c6 100644
--- a/boa/src/vm/code_block.rs
+++ b/boa/src/vm/code_block.rs
@@ -16,15 +16,12 @@ use crate::{
     object::{internal_methods::get_prototype_from_constructor, JsObject, ObjectData},
     property::PropertyDescriptor,
     syntax::ast::node::FormalParameter,
-    vm::Opcode,
+    vm::{call_frame::FinallyReturn, CallFrame, Opcode},
     Context, JsResult, JsString, JsValue,
 };
 use gc::Gc;
-
 use std::{convert::TryInto, fmt::Write, mem::size_of};
 
-use super::CallFrame;
-
 /// This represents whether a value can be read from [`CodeBlock`] code.
 pub unsafe trait Readable {}
 
@@ -103,7 +100,7 @@ impl CodeBlock {
     ///
     /// Does not check if read happens out-of-bounds.
     pub unsafe fn read_unchecked<T: Readable>(&self, offset: usize) -> T {
-        // This has to be an unaligned read because we can't gurantee that
+        // This has to be an unaligned read because we can't guarantee that
         // the types are aligned.
         self.code.as_ptr().add(offset).cast::<T>().read_unaligned()
     }
@@ -150,8 +147,8 @@ impl CodeBlock {
             | Opcode::Jump
             | Opcode::JumpIfFalse
             | Opcode::JumpIfNotUndefined
-            | Opcode::FinallyJump
-            | Opcode::TryStart
+            | Opcode::CatchStart
+            | Opcode::FinallySetJump
             | Opcode::Case
             | Opcode::Default
             | Opcode::LogicalAnd
@@ -167,6 +164,13 @@ impl CodeBlock {
                 *pc += size_of::<u32>();
                 result
             }
+            Opcode::TryStart => {
+                let operand1 = self.read::<u32>(*pc);
+                *pc += size_of::<u32>();
+                let operand2 = self.read::<u32>(*pc);
+                *pc += size_of::<u32>();
+                format!("{}, {}", operand1, operand2)
+            }
             Opcode::GetFunction => {
                 let operand = self.read::<u32>(*pc);
                 *pc += size_of::<u32>();
@@ -177,15 +181,18 @@ impl CodeBlock {
                     self.functions[operand as usize].length
                 )
             }
-            Opcode::DefVar
+            Opcode::DefInitArg
+            | Opcode::DefVar
             | Opcode::DefInitVar
             | Opcode::DefLet
             | Opcode::DefInitLet
             | Opcode::DefInitConst
             | Opcode::GetName
+            | Opcode::GetNameOrUndefined
             | Opcode::SetName
             | Opcode::GetPropertyByName
             | Opcode::SetPropertyByName
+            | Opcode::DefineOwnPropertyByName
             | Opcode::SetPropertyGetterByName
             | Opcode::SetPropertySetterByName
             | Opcode::DeletePropertyByName
@@ -240,26 +247,36 @@ impl CodeBlock {
             | Opcode::Dec
             | Opcode::GetPropertyByValue
             | Opcode::SetPropertyByValue
+            | Opcode::DefineOwnPropertyByValue
             | Opcode::SetPropertyGetterByValue
             | Opcode::SetPropertySetterByValue
             | Opcode::DeletePropertyByValue
             | Opcode::ToBoolean
             | Opcode::Throw
             | Opcode::TryEnd
+            | Opcode::CatchEnd
+            | Opcode::CatchEnd2
             | Opcode::FinallyStart
             | Opcode::FinallyEnd
             | Opcode::This
             | Opcode::Return
             | Opcode::PushDeclarativeEnvironment
+            | Opcode::PushFunctionEnvironment
             | Opcode::PopEnvironment
             | Opcode::InitIterator
             | Opcode::IteratorNext
+            | Opcode::IteratorNextFull
+            | Opcode::IteratorClose
             | Opcode::IteratorToArray
             | Opcode::RequireObjectCoercible
             | Opcode::ValueNotNullOrUndefined
+            | Opcode::RestParameterInit
+            | Opcode::RestParameterPop
             | Opcode::PushValueToArray
             | Opcode::PushIteratorToArray
             | Opcode::PushNewArray
+            | Opcode::PopOnReturnAdd
+            | Opcode::PopOnReturnSub
             | Opcode::Nop => String::new(),
         }
     }
@@ -343,9 +360,7 @@ impl std::fmt::Display for CodeBlock {
 
 #[derive(Debug)]
 #[allow(missing_copy_implementations)]
-pub struct JsVmFunction {
-    inner: (),
-}
+pub struct JsVmFunction {}
 
 impl JsVmFunction {
     #[allow(clippy::new_ret_no_self)]
@@ -512,8 +527,10 @@ impl JsObject {
                     has_parameter_expressions = has_parameter_expressions || param.init().is_some();
                     arguments_in_parameter_names =
                         arguments_in_parameter_names || param.names().contains(&"arguments");
-                    is_simple_parameter_list =
-                        is_simple_parameter_list && !param.is_rest_param() && param.init().is_none()
+                    is_simple_parameter_list = is_simple_parameter_list
+                        && !param.is_rest_param()
+                        && param.is_identifier()
+                        && param.init().is_none()
                 }
 
                 // An arguments object is added when all of the following conditions are met
@@ -543,37 +560,53 @@ impl JsObject {
                     local_env.initialize_binding("arguments", arguments_obj.into(), context)?;
                 }
 
-                // Add argument bindings to the function environment
-                for (i, param) in code.params.iter().enumerate() {
-                    // Rest Parameters
-                    if param.is_rest_param() {
-                        Function::add_rest_param(param, i, args, context, &local_env);
-                        break;
-                    }
+                let arg_count = args.len();
 
-                    let value = match args.get(i).cloned() {
-                        None => JsValue::undefined(),
-                        Some(value) => value,
-                    };
+                // Push function arguments to the stack.
+                let args = if code.params.len() > args.len() {
+                    let mut v = args.to_vec();
+                    v.extend(vec![JsValue::Undefined; code.params.len() - args.len()]);
+                    v
+                } else {
+                    args.to_vec()
+                };
 
-                    Function::add_arguments_to_environment(param, value, &local_env, context);
+                for arg in args.iter().rev() {
+                    context.vm.push(arg)
                 }
 
+                let param_count = code.params.len();
+
+                let this = if this.is_null_or_undefined() {
+                    context
+                        .get_global_this_binding()
+                        .expect("global env must have this binding")
+                } else {
+                    this.to_object(context)
+                        .expect("conversion to object cannot fail here")
+                        .into()
+                };
+
                 context.vm.push_frame(CallFrame {
                     prev: None,
                     code,
-                    this: this.clone(),
+                    this,
                     pc: 0,
-                    fp: context.vm.stack.len(),
-                    environment: local_env,
-                    catch: None,
+                    catch: Vec::new(),
+                    finally_return: FinallyReturn::None,
+                    finally_jump: Vec::new(),
+                    pop_on_return: 0,
                     pop_env_on_return: 0,
-                    finally_no_jump: false,
+                    param_count,
+                    arg_count,
                 });
 
                 let result = context.run();
 
                 context.pop_environment();
+                if has_parameter_expressions {
+                    context.pop_environment();
+                }
 
                 result
             }
@@ -665,8 +698,10 @@ impl JsObject {
                     has_parameter_expressions = has_parameter_expressions || param.init().is_some();
                     arguments_in_parameter_names =
                         arguments_in_parameter_names || param.names().contains(&"arguments");
-                    is_simple_parameter_list =
-                        is_simple_parameter_list && !param.is_rest_param() && param.init().is_none()
+                    is_simple_parameter_list = is_simple_parameter_list
+                        && !param.is_rest_param()
+                        && param.is_identifier()
+                        && param.init().is_none()
                 }
 
                 // An arguments object is added when all of the following conditions are met
@@ -696,41 +731,61 @@ impl JsObject {
                     local_env.initialize_binding("arguments", arguments_obj.into(), context)?;
                 }
 
-                // Add argument bindings to the function environment
-                for (i, param) in code.params.iter().enumerate() {
-                    // Rest Parameters
-                    if param.is_rest_param() {
-                        Function::add_rest_param(param, i, args, context, &local_env);
-                        break;
-                    }
+                let arg_count = args.len();
 
-                    let value = match args.get(i).cloned() {
-                        None => JsValue::undefined(),
-                        Some(value) => value,
-                    };
+                // Push function arguments to the stack.
+                let args = if code.params.len() > args.len() {
+                    let mut v = args.to_vec();
+                    v.extend(vec![JsValue::Undefined; code.params.len() - args.len()]);
+                    v
+                } else {
+                    args.to_vec()
+                };
 
-                    Function::add_arguments_to_environment(param, value, &local_env, context);
+                for arg in args.iter().rev() {
+                    context.vm.push(arg)
                 }
 
+                let param_count = code.params.len();
+
+                let this = if this.is_null_or_undefined() {
+                    context
+                        .get_global_this_binding()
+                        .expect("global env must have this binding")
+                } else {
+                    this.to_object(context)
+                        .expect("conversion to object cannot fail here")
+                        .into()
+                };
+
                 context.vm.push_frame(CallFrame {
                     prev: None,
                     code,
                     this,
                     pc: 0,
-                    fp: context.vm.stack.len(),
-                    environment: local_env,
-                    catch: None,
+                    catch: Vec::new(),
+                    finally_return: FinallyReturn::None,
+                    finally_jump: Vec::new(),
+                    pop_on_return: 0,
                     pop_env_on_return: 0,
-                    finally_no_jump: false,
+                    param_count,
+                    arg_count,
                 });
 
-                let _result = context.run()?;
+                let result = context.run()?;
 
-                let result = context.get_this_binding();
+                let this = context.get_this_binding();
 
                 context.pop_environment();
+                if has_parameter_expressions {
+                    context.pop_environment();
+                }
 
-                result
+                if result.is_object() {
+                    Ok(result)
+                } else {
+                    this
+                }
             }
         }
     }
diff --git a/boa/src/vm/mod.rs b/boa/src/vm/mod.rs
index 7187cc575a..c7b52ff195 100644
--- a/boa/src/vm/mod.rs
+++ b/boa/src/vm/mod.rs
@@ -3,22 +3,25 @@
 //! plus an interpreter to execute those instructions
 
 use crate::{
-    builtins::{iterable::IteratorRecord, Array, ForInIterator},
+    builtins::{iterable::IteratorRecord, Array, ForInIterator, Number},
     environment::{
         declarative_environment_record::DeclarativeEnvironmentRecord,
-        lexical_environment::VariableScope,
+        function_environment_record::{BindingStatus, FunctionEnvironmentRecord},
+        lexical_environment::{Environment, VariableScope},
     },
     property::PropertyDescriptor,
-    vm::code_block::Readable,
+    value::Numeric,
+    vm::{call_frame::CatchAddresses, code_block::Readable},
     BoaProfiler, Context, JsBigInt, JsResult, JsString, JsValue,
 };
-use std::{convert::TryInto, mem::size_of, time::Instant};
+use std::{convert::TryInto, mem::size_of, ops::Neg, time::Instant};
 
 mod call_frame;
 mod code_block;
 mod opcode;
 
 pub use call_frame::CallFrame;
+pub(crate) use call_frame::FinallyReturn;
 pub use code_block::{CodeBlock, JsVmFunction};
 pub use opcode::Opcode;
 
@@ -166,10 +169,10 @@ impl Context {
             }
             Opcode::PushIteratorToArray => {
                 let next_function = self.vm.pop();
-                let for_in_iterator = self.vm.pop();
+                let iterator = self.vm.pop();
                 let array = self.vm.pop();
 
-                let iterator = IteratorRecord::new(for_in_iterator, next_function);
+                let iterator = IteratorRecord::new(iterator, next_function);
                 loop {
                     let next = iterator.next(self)?;
 
@@ -255,14 +258,17 @@ impl Context {
                 self.vm.push(value);
             }
             Opcode::Neg => {
-                let value = self.vm.pop().neg(self)?;
-                self.vm.push(value);
+                let value = self.vm.pop();
+                match value.to_numeric(self)? {
+                    Numeric::Number(number) => self.vm.push(number.neg()),
+                    Numeric::BigInt(bigint) => self.vm.push(JsBigInt::neg(&bigint)),
+                }
             }
             Opcode::Inc => {
                 let value = self.vm.pop();
                 match value.to_numeric(self)? {
-                    crate::value::Numeric::Number(number) => self.vm.push(number + 1f64),
-                    crate::value::Numeric::BigInt(bigint) => {
+                    Numeric::Number(number) => self.vm.push(number + 1f64),
+                    Numeric::BigInt(bigint) => {
                         self.vm.push(JsBigInt::add(&bigint, &JsBigInt::one()))
                     }
                 }
@@ -270,8 +276,8 @@ impl Context {
             Opcode::Dec => {
                 let value = self.vm.pop();
                 match value.to_numeric(self)? {
-                    crate::value::Numeric::Number(number) => self.vm.push(number - 1f64),
-                    crate::value::Numeric::BigInt(bigint) => {
+                    Numeric::Number(number) => self.vm.push(number - 1f64),
+                    Numeric::BigInt(bigint) => {
                         self.vm.push(JsBigInt::sub(&bigint, &JsBigInt::one()))
                     }
                 }
@@ -281,15 +287,21 @@ impl Context {
                 self.vm.push(!value.to_boolean());
             }
             Opcode::BitNot => {
-                let target = self.vm.pop();
-                let num = target.to_number(self)?;
-                let value = if num.is_nan() {
-                    -1
-                } else {
-                    // TODO: this is not spec compliant.
-                    !(num as i32)
-                };
-                self.vm.push(value);
+                let value = self.vm.pop();
+                match value.to_numeric(self)? {
+                    Numeric::Number(number) => self.vm.push(Number::not(number)),
+                    Numeric::BigInt(bigint) => self.vm.push(JsBigInt::not(&bigint)),
+                }
+            }
+            Opcode::DefInitArg => {
+                let index = self.vm.read::<u32>();
+                let name = self.vm.frame().code.variables[index as usize].clone();
+                let value = self.vm.pop();
+                let local_env = self.get_current_environment();
+                local_env
+                    .create_mutable_binding(name.as_ref(), false, true, self)
+                    .expect("Failed to create argument binding");
+                self.initialize_binding(name.as_ref(), value)?;
             }
             Opcode::DefVar => {
                 let index = self.vm.read::<u32>();
@@ -342,18 +354,27 @@ impl Context {
                 let value = self.get_binding_value(&name)?;
                 self.vm.push(value);
             }
+            Opcode::GetNameOrUndefined => {
+                let index = self.vm.read::<u32>();
+                let name = self.vm.frame().code.variables[index as usize].clone();
+
+                let value = if self.has_binding(&name)? {
+                    self.get_binding_value(&name)?
+                } else {
+                    JsValue::Undefined
+                };
+                self.vm.push(value)
+            }
             Opcode::SetName => {
                 let index = self.vm.read::<u32>();
                 let value = self.vm.pop();
                 let name = self.vm.frame().code.variables[index as usize].clone();
 
-                if self.has_binding(name.as_ref())? {
-                    // Binding already exists
-                    self.set_mutable_binding(name.as_ref(), value, self.strict())?;
-                } else {
-                    self.create_mutable_binding(name.as_ref(), true, VariableScope::Function)?;
-                    self.initialize_binding(name.as_ref(), value)?;
-                }
+                self.set_mutable_binding(
+                    name.as_ref(),
+                    value,
+                    self.strict() || self.vm.frame().code.strict,
+                )?;
             }
             Opcode::Jump => {
                 let address = self.vm.read::<u32>();
@@ -370,15 +391,15 @@ impl Context {
                 let value = self.vm.pop();
                 if !value.is_undefined() {
                     self.vm.frame_mut().pc = address as usize;
+                    self.vm.push(value)
                 }
-                self.vm.push(value);
             }
             Opcode::LogicalAnd => {
                 let exit = self.vm.read::<u32>();
                 let lhs = self.vm.pop();
                 if !lhs.to_boolean() {
                     self.vm.frame_mut().pc = exit as usize;
-                    self.vm.push(false);
+                    self.vm.push(lhs);
                 }
             }
             Opcode::LogicalOr => {
@@ -386,7 +407,7 @@ impl Context {
                 let lhs = self.vm.pop();
                 if lhs.to_boolean() {
                     self.vm.frame_mut().pc = exit as usize;
-                    self.vm.push(true);
+                    self.vm.push(lhs);
                 }
             }
             Opcode::Coalesce => {
@@ -417,18 +438,18 @@ impl Context {
                 self.vm.push(result)
             }
             Opcode::GetPropertyByValue => {
-                let value = self.vm.pop();
+                let object = self.vm.pop();
                 let key = self.vm.pop();
-                let object = if let Some(object) = value.as_object() {
+                let object = if let Some(object) = object.as_object() {
                     object.clone()
                 } else {
-                    value.to_object(self)?
+                    object.to_object(self)?
                 };
 
                 let key = key.to_property_key(self)?;
-                let result = object.get(key, self)?;
+                let value = object.get(key, self)?;
 
-                self.vm.push(result)
+                self.vm.push(value)
             }
             Opcode::SetPropertyByName => {
                 let index = self.vm.read::<u32>();
@@ -443,7 +464,36 @@ impl Context {
 
                 let name = self.vm.frame().code.variables[index as usize].clone();
 
-                object.set(name, value, true, self)?;
+                object.set(
+                    name,
+                    value,
+                    self.strict() || self.vm.frame().code.strict,
+                    self,
+                )?;
+            }
+            Opcode::DefineOwnPropertyByName => {
+                let index = self.vm.read::<u32>();
+
+                let object = self.vm.pop();
+                let value = self.vm.pop();
+                let object = if let Some(object) = object.as_object() {
+                    object.clone()
+                } else {
+                    object.to_object(self)?
+                };
+
+                let name = self.vm.frame().code.variables[index as usize].clone();
+
+                object.__define_own_property__(
+                    name.into(),
+                    PropertyDescriptor::builder()
+                        .value(value)
+                        .writable(true)
+                        .enumerable(true)
+                        .configurable(true)
+                        .build(),
+                    self,
+                )?;
             }
             Opcode::SetPropertyByValue => {
                 let object = self.vm.pop();
@@ -456,7 +506,35 @@ impl Context {
                 };
 
                 let key = key.to_property_key(self)?;
-                object.set(key, value, true, self)?;
+                object.set(
+                    key,
+                    value,
+                    self.strict() || self.vm.frame().code.strict,
+                    self,
+                )?;
+            }
+            Opcode::DefineOwnPropertyByValue => {
+                let value = self.vm.pop();
+                let key = self.vm.pop();
+                let object = self.vm.pop();
+                let object = if let Some(object) = object.as_object() {
+                    object.clone()
+                } else {
+                    object.to_object(self)?
+                };
+
+                let key = key.to_property_key(self)?;
+
+                object.__define_own_property__(
+                    key,
+                    PropertyDescriptor::builder()
+                        .value(value)
+                        .writable(true)
+                        .enumerable(true)
+                        .configurable(true)
+                        .build(),
+                    self,
+                )?;
             }
             Opcode::SetPropertyGetterByName => {
                 let index = self.vm.read::<u32>();
@@ -484,9 +562,9 @@ impl Context {
                 )?;
             }
             Opcode::SetPropertyGetterByValue => {
-                let object = self.vm.pop();
-                let key = self.vm.pop();
                 let value = self.vm.pop();
+                let key = self.vm.pop();
+                let object = self.vm.pop();
                 let object = object.to_object(self)?;
                 let name = key.to_property_key(self)?;
                 let set = object
@@ -530,9 +608,9 @@ impl Context {
                 )?;
             }
             Opcode::SetPropertySetterByValue => {
-                let object = self.vm.pop();
-                let key = self.vm.pop();
                 let value = self.vm.pop();
+                let key = self.vm.pop();
+                let object = self.vm.pop();
                 let object = object.to_object(self)?;
                 let name = key.to_property_key(self)?;
                 let get = object
@@ -556,6 +634,9 @@ impl Context {
                 let key = self.vm.frame().code.variables[index as usize].clone();
                 let object = self.vm.pop();
                 let result = object.to_object(self)?.__delete__(&key.into(), self)?;
+                if !result && self.strict() || self.vm.frame().code.strict {
+                    return Err(self.construct_type_error("Cannot delete property"));
+                }
                 self.vm.push(result);
             }
             Opcode::DeletePropertyByValue => {
@@ -564,6 +645,9 @@ impl Context {
                 let result = object
                     .to_object(self)?
                     .__delete__(&key.to_property_key(self)?, self)?;
+                if !result && self.strict() || self.vm.frame().code.strict {
+                    return Err(self.construct_type_error("Cannot delete property"));
+                }
                 self.vm.push(result);
             }
             Opcode::CopyDataProperties => {
@@ -574,8 +658,8 @@ impl Context {
                 }
                 let value = self.vm.pop();
                 let object = value.as_object().unwrap();
-                let rest_obj = self.vm.pop();
-                object.copy_data_properties(&rest_obj, excluded_keys, self)?;
+                let source = self.vm.pop();
+                object.copy_data_properties(&source, excluded_keys, self)?;
                 self.vm.push(value);
             }
             Opcode::Throw => {
@@ -583,27 +667,77 @@ impl Context {
                 return Err(value);
             }
             Opcode::TryStart => {
-                let index = self.vm.read::<u32>();
-                self.vm.frame_mut().catch = Some(index);
-                self.vm.frame_mut().finally_no_jump = false;
+                let next = self.vm.read::<u32>();
+                let finally = self.vm.read::<u32>();
+                let finally = if finally != 0 { Some(finally) } else { None };
+                self.vm
+                    .frame_mut()
+                    .catch
+                    .push(CatchAddresses { next, finally });
+                self.vm.frame_mut().finally_jump.push(None);
+                self.vm.frame_mut().finally_return = FinallyReturn::None;
             }
             Opcode::TryEnd => {
-                self.vm.frame_mut().catch = None;
+                self.vm.frame_mut().catch.pop();
+                self.vm.frame_mut().finally_return = FinallyReturn::None;
+            }
+            Opcode::CatchStart => {
+                let finally = self.vm.read::<u32>();
+                self.vm.frame_mut().catch.push(CatchAddresses {
+                    next: finally,
+                    finally: Some(finally),
+                });
+            }
+            Opcode::CatchEnd => {
+                self.vm.frame_mut().catch.pop();
+                self.vm.frame_mut().finally_return = FinallyReturn::None;
+            }
+            Opcode::CatchEnd2 => {
+                self.vm.frame_mut().finally_return = FinallyReturn::None;
             }
             Opcode::FinallyStart => {
-                self.vm.frame_mut().finally_no_jump = true;
+                *self
+                    .vm
+                    .frame_mut()
+                    .finally_jump
+                    .last_mut()
+                    .expect("finally jump must exist here") = None;
             }
             Opcode::FinallyEnd => {
-                if let Some(value) = self.vm.stack.pop() {
-                    return Err(value);
+                let address = self
+                    .vm
+                    .frame_mut()
+                    .finally_jump
+                    .pop()
+                    .expect("finally jump must exist here");
+                match self.vm.frame_mut().finally_return {
+                    FinallyReturn::None => {
+                        if let Some(address) = address {
+                            self.vm.frame_mut().pc = address as usize;
+                        }
+                    }
+                    FinallyReturn::Ok => {
+                        for _ in 0..self.vm.frame().pop_env_on_return {
+                            self.pop_environment();
+                        }
+                        self.vm.frame_mut().pop_env_on_return = 0;
+                        let _ = self.vm.pop_frame();
+                        return Ok(true);
+                    }
+                    FinallyReturn::Err => {
+                        self.vm.frame_mut().finally_return = FinallyReturn::None;
+                        return Err(self.vm.pop());
+                    }
                 }
             }
-            Opcode::FinallyJump => {
+            Opcode::FinallySetJump => {
                 let address = self.vm.read::<u32>();
-                if !self.vm.frame().finally_no_jump {
-                    self.vm.frame_mut().pc = address as usize;
-                }
-                self.vm.frame_mut().finally_no_jump = false;
+                *self
+                    .vm
+                    .frame_mut()
+                    .finally_jump
+                    .last_mut()
+                    .expect("finally jump must exist here") = Some(address);
             }
             Opcode::This => {
                 let this = self.get_this_binding()?;
@@ -628,7 +762,7 @@ impl Context {
             Opcode::GetFunction => {
                 let index = self.vm.read::<u32>();
                 let code = self.vm.frame().code.functions[index as usize].clone();
-                let environment = self.vm.frame().environment.clone();
+                let environment = self.get_current_environment();
                 let function = JsVmFunction::new(code, environment, self);
                 self.vm.push(function);
             }
@@ -636,21 +770,26 @@ impl Context {
                 if self.vm.stack_size_limit <= self.vm.stack.len() {
                     return self.throw_range_error("Maximum call stack size exceeded");
                 }
-                let argc = self.vm.read::<u32>();
-                let mut args = Vec::with_capacity(argc as usize);
-                for _ in 0..argc {
-                    args.push(self.vm.pop());
+                let argument_count = self.vm.read::<u32>();
+                let mut arguments = Vec::with_capacity(argument_count as usize);
+                for _ in 0..argument_count {
+                    arguments.push(self.vm.pop());
                 }
+                arguments.reverse();
 
                 let func = self.vm.pop();
-                let this = self.vm.pop();
+                let mut this = self.vm.pop();
 
                 let object = match func {
                     JsValue::Object(ref object) if object.is_callable() => object.clone(),
                     _ => return self.throw_type_error("not a callable function"),
                 };
 
-                let result = object.__call__(&this, &args, self)?;
+                if this.is_null_or_undefined() {
+                    this = self.global_object().into();
+                }
+
+                let result = object.__call__(&this, &arguments, self)?;
 
                 self.vm.push(result);
             }
@@ -658,32 +797,37 @@ impl Context {
                 if self.vm.stack_size_limit <= self.vm.stack.len() {
                     return self.throw_range_error("Maximum call stack size exceeded");
                 }
-                let argc = self.vm.read::<u32>();
-                let mut args = Vec::with_capacity(argc as usize);
-                for _ in 0..(argc - 1) {
-                    args.push(self.vm.pop());
+                let argument_count = self.vm.read::<u32>();
+                let rest_argument = self.vm.pop();
+                let mut arguments = Vec::with_capacity(argument_count as usize);
+                for _ in 0..(argument_count - 1) {
+                    arguments.push(self.vm.pop());
                 }
-                let rest_arg_value = self.vm.pop();
+                arguments.reverse();
                 let func = self.vm.pop();
-                let this = self.vm.pop();
+                let mut this = self.vm.pop();
 
-                let iterator_record = rest_arg_value.get_iterator(self, None, None)?;
-                let mut rest_args = Vec::new();
+                let iterator_record = rest_argument.get_iterator(self, None, None)?;
+                let mut rest_arguments = Vec::new();
                 loop {
                     let next = iterator_record.next(self)?;
                     if next.done {
                         break;
                     }
-                    rest_args.push(next.value);
+                    rest_arguments.push(next.value);
                 }
-                args.append(&mut rest_args);
+                arguments.append(&mut rest_arguments);
 
                 let object = match func {
                     JsValue::Object(ref object) if object.is_callable() => object.clone(),
                     _ => return self.throw_type_error("not a callable function"),
                 };
 
-                let result = object.__call__(&this, &args, self)?;
+                if this.is_null_or_undefined() {
+                    this = self.global_object().into();
+                }
+
+                let result = object.__call__(&this, &arguments, self)?;
 
                 self.vm.push(result);
             }
@@ -691,17 +835,18 @@ impl Context {
                 if self.vm.stack_size_limit <= self.vm.stack.len() {
                     return self.throw_range_error("Maximum call stack size exceeded");
                 }
-                let argc = self.vm.read::<u32>();
-                let mut args = Vec::with_capacity(argc as usize);
-                for _ in 0..argc {
-                    args.push(self.vm.pop());
+                let argument_count = self.vm.read::<u32>();
+                let mut arguments = Vec::with_capacity(argument_count as usize);
+                for _ in 0..argument_count {
+                    arguments.push(self.vm.pop());
                 }
+                arguments.reverse();
                 let func = self.vm.pop();
 
                 let result = func
                     .as_constructor()
                     .ok_or_else(|| self.construct_type_error("not a constructor"))
-                    .and_then(|cons| cons.__construct__(&args, &cons.clone().into(), self))?;
+                    .and_then(|cons| cons.__construct__(&arguments, &cons.clone().into(), self))?;
 
                 self.vm.push(result);
             }
@@ -709,45 +854,83 @@ impl Context {
                 if self.vm.stack_size_limit <= self.vm.stack.len() {
                     return self.throw_range_error("Maximum call stack size exceeded");
                 }
-                let argc = self.vm.read::<u32>();
-                let mut args = Vec::with_capacity(argc as usize);
-                for _ in 0..(argc - 1) {
-                    args.push(self.vm.pop());
+                let argument_count = self.vm.read::<u32>();
+                let rest_argument = self.vm.pop();
+                let mut arguments = Vec::with_capacity(argument_count as usize);
+                for _ in 0..(argument_count - 1) {
+                    arguments.push(self.vm.pop());
                 }
-                let rest_arg_value = self.vm.pop();
+                arguments.reverse();
                 let func = self.vm.pop();
 
-                let iterator_record = rest_arg_value.get_iterator(self, None, None)?;
-                let mut rest_args = Vec::new();
+                let iterator_record = rest_argument.get_iterator(self, None, None)?;
+                let mut rest_arguments = Vec::new();
                 loop {
                     let next = iterator_record.next(self)?;
                     if next.done {
                         break;
                     }
-                    rest_args.push(next.value);
+                    rest_arguments.push(next.value);
                 }
-                args.append(&mut rest_args);
+                arguments.append(&mut rest_arguments);
 
                 let result = func
                     .as_constructor()
                     .ok_or_else(|| self.construct_type_error("not a constructor"))
-                    .and_then(|cons| cons.__construct__(&args, &cons.clone().into(), self))?;
+                    .and_then(|cons| cons.__construct__(&arguments, &cons.clone().into(), self))?;
 
                 self.vm.push(result);
             }
             Opcode::Return => {
-                for _ in 0..self.vm.frame().pop_env_on_return {
-                    self.pop_environment();
+                if let Some(finally_address) = self.vm.frame().catch.last().and_then(|c| c.finally)
+                {
+                    let frame = self.vm.frame_mut();
+                    frame.pc = finally_address as usize;
+                    frame.finally_return = FinallyReturn::Ok;
+                    frame.catch.pop();
+                } else {
+                    for _ in 0..self.vm.frame().pop_env_on_return {
+                        self.pop_environment();
+                    }
+                    self.vm.frame_mut().pop_env_on_return = 0;
+                    let _ = self.vm.pop_frame();
+                    return Ok(true);
                 }
-                self.vm.frame_mut().pop_env_on_return = 0;
-                let _ = self.vm.pop_frame();
-                return Ok(true);
             }
             Opcode::PushDeclarativeEnvironment => {
                 let env = self.get_current_environment();
                 self.push_environment(DeclarativeEnvironmentRecord::new(Some(env)));
                 self.vm.frame_mut().pop_env_on_return += 1;
             }
+            Opcode::PushFunctionEnvironment => {
+                let is_constructor = self.vm.frame().code.constructor;
+                let is_lexical = self.vm.frame().code.this_mode.is_lexical();
+                let current_env = self.get_current_environment();
+                let this = &self.vm.frame().this;
+
+                let new_env = FunctionEnvironmentRecord::new(
+                    this.clone()
+                        .as_object()
+                        .expect("this must always be an object")
+                        .clone(),
+                    if is_constructor || !is_lexical {
+                        Some(this.clone())
+                    } else {
+                        None
+                    },
+                    Some(current_env),
+                    if is_lexical {
+                        BindingStatus::Lexical
+                    } else {
+                        BindingStatus::Uninitialized
+                    },
+                    JsValue::undefined(),
+                    self,
+                )?;
+
+                let new_env: Environment = new_env.into();
+                self.push_environment(new_env);
+            }
             Opcode::PopEnvironment => {
                 let _ = self.pop_environment();
                 self.vm.frame_mut().pop_env_on_return -= 1;
@@ -761,50 +944,67 @@ impl Context {
                 }
 
                 let object = object.to_object(self)?;
-                let for_in_iterator =
-                    ForInIterator::create_for_in_iterator(JsValue::new(object), self);
-                let next_function = for_in_iterator
+                let iterator = ForInIterator::create_for_in_iterator(JsValue::new(object), self);
+                let next_function = iterator
                     .get_property("next")
                     .as_ref()
                     .map(|p| p.expect_value())
                     .cloned()
                     .ok_or_else(|| self.construct_type_error("Could not find property `next`"))?;
 
-                self.vm.push(for_in_iterator);
+                self.vm.push(iterator);
                 self.vm.push(next_function);
             }
             Opcode::InitIterator => {
-                let iterable = self.vm.pop();
-                let iterator = iterable.get_iterator(self, None, None)?;
-
+                let object = self.vm.pop();
+                let iterator = object.get_iterator(self, None, None)?;
                 self.vm.push(iterator.iterator_object());
                 self.vm.push(iterator.next_function());
             }
             Opcode::IteratorNext => {
                 let next_function = self.vm.pop();
-                let for_in_iterator = self.vm.pop();
+                let iterator = self.vm.pop();
 
-                let iterator = IteratorRecord::new(for_in_iterator.clone(), next_function.clone());
-                let iterator_result = iterator.next(self)?;
+                let iterator_record = IteratorRecord::new(iterator.clone(), next_function.clone());
+                let iterator_result = iterator_record.next(self)?;
 
-                self.vm.push(for_in_iterator);
+                self.vm.push(iterator);
                 self.vm.push(next_function);
                 self.vm.push(iterator_result.value);
             }
+            Opcode::IteratorNextFull => {
+                let next_function = self.vm.pop();
+                let iterator = self.vm.pop();
+
+                let iterator_record = IteratorRecord::new(iterator.clone(), next_function.clone());
+                let iterator_result = iterator_record.next(self)?;
+
+                self.vm.push(iterator);
+                self.vm.push(next_function);
+                self.vm.push(iterator_result.done);
+                self.vm.push(iterator_result.value);
+            }
+            Opcode::IteratorClose => {
+                let done = self.vm.pop();
+                let next_function = self.vm.pop();
+                let iterator = self.vm.pop();
+                if !done.as_boolean().unwrap() {
+                    let iterator_record = IteratorRecord::new(iterator, next_function);
+                    iterator_record.close(Ok(JsValue::Null), self)?;
+                }
+            }
             Opcode::IteratorToArray => {
                 let next_function = self.vm.pop();
-                let for_in_iterator = self.vm.pop();
+                let iterator = self.vm.pop();
 
-                let iterator = IteratorRecord::new(for_in_iterator.clone(), next_function.clone());
+                let iterator_record = IteratorRecord::new(iterator.clone(), next_function.clone());
                 let mut values = Vec::new();
 
                 loop {
-                    let next = iterator.next(self)?;
-
+                    let next = iterator_record.next(self)?;
                     if next.done {
                         break;
                     }
-
                     values.push(next.value);
                 }
 
@@ -813,7 +1013,7 @@ impl Context {
 
                 Array::add_to_array_object(&array.clone().into(), &values, self)?;
 
-                self.vm.push(for_in_iterator);
+                self.vm.push(iterator);
                 self.vm.push(next_function);
                 self.vm.push(array);
             }
@@ -821,29 +1021,32 @@ impl Context {
                 let address = self.vm.read::<u32>();
 
                 let next_function = self.vm.pop();
-                let for_in_iterator = self.vm.pop();
+                let iterator = self.vm.pop();
 
-                let iterator = IteratorRecord::new(for_in_iterator.clone(), next_function.clone());
-                let iterator_result = iterator.next(self)?;
+                let iterator_record = IteratorRecord::new(iterator.clone(), next_function.clone());
+                let iterator_result = iterator_record.next(self)?;
                 if iterator_result.done {
                     self.vm.frame_mut().pc = address as usize;
                     self.vm.frame_mut().pop_env_on_return -= 1;
                     self.pop_environment();
+                    self.vm.push(iterator);
+                    self.vm.push(next_function);
                 } else {
-                    self.vm.push(for_in_iterator);
+                    self.vm.push(iterator);
                     self.vm.push(next_function);
                     self.vm.push(iterator_result.value);
                 }
             }
             Opcode::ConcatToString => {
-                let n = self.vm.read::<u32>();
-                let mut s = JsString::new("");
-
-                for _ in 0..n {
-                    let obj = self.vm.pop();
-                    s = JsString::concat(s, obj.to_string(self)?);
+                let value_count = self.vm.read::<u32>();
+                let mut strings = Vec::with_capacity(value_count as usize);
+                for _ in 0..value_count {
+                    strings.push(self.vm.pop().to_string(self)?);
                 }
-
+                strings.reverse();
+                let s = JsString::concat_array(
+                    &strings.iter().map(|s| s.as_str()).collect::<Vec<&str>>(),
+                );
                 self.vm.push(s);
             }
             Opcode::RequireObjectCoercible => {
@@ -861,6 +1064,39 @@ impl Context {
                 }
                 self.vm.push(value);
             }
+            Opcode::RestParameterInit => {
+                let arg_count = self.vm.frame().arg_count;
+                let param_count = self.vm.frame().param_count;
+                if arg_count >= param_count {
+                    let rest_count = arg_count - param_count + 1;
+                    let mut args = Vec::with_capacity(rest_count);
+                    for _ in 0..rest_count {
+                        args.push(self.vm.pop());
+                    }
+                    let array = Array::new_array(self);
+                    Array::add_to_array_object(&array, &args, self).unwrap();
+                    self.vm.push(array);
+                } else {
+                    self.vm.pop();
+                    let array = Array::new_array(self);
+                    self.vm.push(array);
+                }
+            }
+            Opcode::RestParameterPop => {
+                let arg_count = self.vm.frame().arg_count;
+                let param_count = self.vm.frame().param_count;
+                if arg_count > param_count {
+                    for _ in 0..(arg_count - param_count) {
+                        self.vm.pop();
+                    }
+                }
+            }
+            Opcode::PopOnReturnAdd => {
+                self.vm.frame_mut().pop_on_return += 1;
+            }
+            Opcode::PopOnReturnSub => {
+                self.vm.frame_mut().pop_on_return -= 1;
+            }
         }
 
         Ok(false)
@@ -945,13 +1181,18 @@ impl Context {
                     }
                 }
                 Err(e) => {
-                    if let Some(address) = self.vm.frame().catch {
+                    if let Some(address) = self.vm.frame().catch.last() {
+                        let address = address.next;
                         if self.vm.frame().pop_env_on_return > 0 {
                             self.pop_environment();
                             self.vm.frame_mut().pop_env_on_return -= 1;
                         }
+                        for _ in 0..self.vm.frame().pop_on_return {
+                            self.vm.pop();
+                        }
                         self.vm.frame_mut().pc = address as usize;
-                        self.vm.frame_mut().catch = None;
+                        self.vm.frame_mut().catch.pop();
+                        self.vm.frame_mut().finally_return = FinallyReturn::Err;
                         self.vm.push(e);
                     } else {
                         for _ in 0..self.vm.frame().pop_env_on_return {
diff --git a/boa/src/vm/opcode.rs b/boa/src/vm/opcode.rs
index f25ad40fc4..5dcd57c45e 100644
--- a/boa/src/vm/opcode.rs
+++ b/boa/src/vm/opcode.rs
@@ -22,21 +22,21 @@ pub enum Opcode {
     ///
     /// Operands:
     ///
-    /// Stack: v1, v2 **=>** v2, v1
+    /// Stack: second, first **=>** first, second
     Swap,
 
     /// Push integer `0` on the stack.
     ///
     /// Operands:
     ///
-    /// Stack: **=>** 0
+    /// Stack: **=>** `0`
     PushZero,
 
     /// Push integer `1` on the stack.
     ///
     /// Operands:
     ///
-    /// Stack: **=>** 1
+    /// Stack: **=>** `1`
     PushOne,
 
     /// Push `i8` value on the stack.
@@ -67,7 +67,7 @@ pub enum Opcode {
     /// Stack: **=>** value
     PushRational,
 
-    /// Push `NaN` teger on the stack.
+    /// Push `NaN` integer on the stack.
     ///
     /// Operands:
     ///
@@ -118,7 +118,7 @@ pub enum Opcode {
 
     /// Push literal value on the stack.
     ///
-    /// Like strings and bigints. The index oprand is used to index into the `literals`
+    /// Like strings and bigints. The index operand is used to index into the `literals`
     /// array to get the value.
     ///
     /// Operands: index: `u32`
@@ -130,22 +130,28 @@ pub enum Opcode {
     ///
     /// Operands:
     ///
-    /// Stack: **=>** object
+    /// Stack: **=>** `{}`
     PushEmptyObject,
 
     /// Push an empty array value on the stack.
     ///
-    /// Stack: **=>** `array`
+    /// Operands:
+    ///
+    /// Stack: **=>** `[]`
     PushNewArray,
 
     /// Push a value to an array.
     ///
-    /// Stack: `array`, `value` **=>** `array`
+    /// Operands:
+    ///
+    /// Stack: array, value **=>** array
     PushValueToArray,
 
     /// Push all iterator values to an array.
     ///
-    /// Stack: `array`, `iterator`, `next_function` **=>** `array`
+    /// Operands:
+    ///
+    /// Stack: array, iterator, next_function **=>** array
     PushIteratorToArray,
 
     /// Binary `+` operator.
@@ -311,7 +317,7 @@ pub enum Opcode {
 
     /// Binary logical `&&` operator.
     ///
-    /// This is a short-circit operator, if the `lhs` value is `false`, then it jumps to `exit` address.
+    /// This is a short-circuit operator, if the `lhs` value is `false`, then it jumps to `exit` address.
     ///
     /// Operands: exit: `u32`
     ///
@@ -320,7 +326,7 @@ pub enum Opcode {
 
     /// Binary logical `||` operator.
     ///
-    /// This is a short-circit operator, if the `lhs` value is `true`, then it jumps to `exit` address.
+    /// This is a short-circuit operator, if the `lhs` value is `true`, then it jumps to `exit` address.
     ///
     /// Operands: exit: `u32`
     ///
@@ -329,7 +335,7 @@ pub enum Opcode {
 
     /// Binary `??` operator.
     ///
-    /// This is a short-circit operator, if the `lhs` value is **not** `null` or `undefined`,
+    /// This is a short-circuit operator, if the `lhs` value is **not** `null` or `undefined`,
     /// then it jumps to `exit` address.
     ///
     /// Operands: exit: `u32`
@@ -386,6 +392,13 @@ pub enum Opcode {
     /// Stack: value **=>** (value - 1)
     Dec,
 
+    /// Declare and initialize a function argument.
+    ///
+    /// Operands: name_index: `u32`
+    ///
+    /// Stack: value **=>**
+    DefInitArg,
+
     /// Declare `var` type variable.
     ///
     /// Operands: name_index: `u32`
@@ -428,6 +441,13 @@ pub enum Opcode {
     /// Stack: **=>** value
     GetName,
 
+    /// Find a binding on the environment chain and push its value. If the binding does not exist push undefined.
+    ///
+    /// Operands: name_index: `u32`
+    ///
+    /// Stack: **=>** value
+    GetNameOrUndefined,
+
     /// Find a binding on the environment chain and assign its value.
     ///
     /// Operands: name_index: `u32`
@@ -462,6 +482,13 @@ pub enum Opcode {
     /// Stack: value, object **=>**
     SetPropertyByName,
 
+    /// Defines a own property of an object by name.
+    ///
+    /// Operands: name_index: `u32`
+    ///
+    /// Stack: value, object **=>**
+    DefineOwnPropertyByName,
+
     /// Sets a property by value of an object.
     ///
     /// Like `object[key] = value`
@@ -471,6 +498,13 @@ pub enum Opcode {
     /// Stack: value, key, object **=>**
     SetPropertyByValue,
 
+    /// Defines a own property of an object by value.
+    ///
+    /// Operands:
+    ///
+    /// Stack: object, key, value **=>**
+    DefineOwnPropertyByValue,
+
     /// Sets a getter property by name of an object.
     ///
     /// Like `get name() value`
@@ -486,7 +520,7 @@ pub enum Opcode {
     ///
     /// Operands:
     ///
-    /// Stack: value, key, object **=>**
+    /// Stack: object, key, value **=>**
     SetPropertyGetterByValue,
 
     /// Sets a setter property by name of an object.
@@ -504,7 +538,7 @@ pub enum Opcode {
     ///
     /// Operands:
     ///
-    /// Stack: value, key, object **=>**
+    /// Stack: object, key, value **=>**
     SetPropertySetterByValue,
 
     /// Deletes a property by name of an object.
@@ -527,9 +561,9 @@ pub enum Opcode {
 
     /// Copy all properties of one object to another object.
     ///
-    /// Operands: number of excluded keys: `u32`
+    /// Operands: excluded_key_count: `u32`
     ///
-    /// Stack: object, rest_object, excluded_key_0 ... excluded_key_n **=>** object
+    /// Stack: source, value, excluded_key_0 ... excluded_key_n **=>** value
     CopyDataProperties,
 
     /// Unconditional jump to address.
@@ -563,27 +597,64 @@ pub enum Opcode {
     ///
     /// Operands:
     ///
-    /// Stack: `exc` **=>**
+    /// Stack: value **=>**
     Throw,
 
     /// Start of a try block.
     ///
-    /// Operands: address: `u32`
+    /// Operands: next_address: `u32`, finally_address: `u32`
+    ///
+    /// Stack: **=>**
     TryStart,
 
     /// End of a try block.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
     TryEnd,
 
+    /// Start of a catch block.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
+    CatchStart,
+
+    /// End of a catch block.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
+    CatchEnd,
+
+    /// End of a catch block.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
+    CatchEnd2,
+
     /// Start of a finally block.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
     FinallyStart,
 
     /// End of a finally block.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
     FinallyEnd,
 
-    /// Jump if the finally block was entered trough a break statement.
+    /// Set the address for a finally jump.
     ///
-    /// Operands: address: `u32`
-    FinallyJump,
+    /// Operands:
+    ///
+    /// Stack: **=>**
+    FinallySetJump,
 
     /// Pops value converts it to boolean and pushes it back.
     ///
@@ -596,15 +667,15 @@ pub enum Opcode {
     ///
     /// Operands:
     ///
-    /// Stack: **=>** `this`
+    /// Stack: **=>** this
     This,
 
     /// Pop the two values of the stack, strict equal compares the two values,
-    /// if true jumps to address, otherwise push the second poped value.
+    /// if true jumps to address, otherwise push the second pop'ed value.
     ///
     /// Operands: address: `u32`
     ///
-    /// Stack: `value`, `cond` **=>** `cond` (if `cond !== value`).
+    /// Stack: value, cond **=>** cond (if `cond !== value`).
     Case,
 
     /// Pops the top of stack and jump to address.
@@ -614,96 +685,169 @@ pub enum Opcode {
     /// Stack: `value` **=>**
     Default,
 
-    /// Get function from the precompiled inner functions.
+    /// Get function from the pre-compiled inner functions.
     ///
     /// Operands: address: `u32`
     ///
-    /// Stack: **=>** `func`
+    /// Stack: **=>** func
     GetFunction,
 
     /// Call a function.
     ///
-    /// Operands: argc: `u32`
+    /// Operands: argument_count: `u32`
     ///
-    /// Stack: `func`, `this`, `arg1`, `arg2`,...`argn` **=>**
+    /// Stack: func, this, argument_1, ... argument_n **=>** result
     Call,
 
     /// Call a function where the last argument is a rest parameter.
     ///
-    /// Operands: argc: `u32`
+    /// Operands: argument_count: `u32`
     ///
-    /// Stack: `func`, `this`, `arg1`, `arg2`,...`argn` **=>**
+    /// Stack: func, this, argument_1, ... argument_n **=>** result
     CallWithRest,
 
     /// Call construct on a function.
     ///
-    /// Operands: argc: `u32`
+    /// Operands: argument_count: `u32`
     ///
-    /// Stack: `func`, `arg1`, `arg2`,...`argn` **=>**
+    /// Stack: func, argument_1, ... argument_n **=>** result
     New,
 
     /// Call construct on a function where the last argument is a rest parameter.
     ///
-    /// Operands: argc: `u32`
+    /// Operands: argument_count: `u32`
     ///
-    /// Stack: `func`, `arg1`, `arg2`,...`argn` **=>**
+    /// Stack: func, argument_1, ... argument_n **=>** result
     NewWithRest,
 
     /// Return from a function.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
     Return,
 
     /// Push a declarative environment.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
     PushDeclarativeEnvironment,
 
+    /// Push a function environment.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
+    PushFunctionEnvironment,
+
     /// Pop the current environment.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
     PopEnvironment,
 
     /// Initialize the iterator for a for..in loop or jump to after the loop if object is null or undefined.
     ///
     /// Operands: address: `u32`
     ///
-    /// Stack: `object` **=>** `for_in_iterator`, `next_function`
+    /// Stack: object **=>** iterator, next_function
     ForInLoopInitIterator,
 
     /// Initialize an iterator.
     ///
-    /// Stack: `object` **=>** `iterator`, `next_function`
+    /// Operands:
+    ///
+    /// Stack: object **=>** iterator, next_function
     InitIterator,
 
     /// Advance the iterator by one and put the value on the stack.
     ///
-    /// Stack: `iterator`, `next_function` **=>** `for_of_iterator`, `next_function`, `next_value`
+    /// Operands:
+    ///
+    /// Stack: iterator, next_function **=>** iterator, next_function, next_value
     IteratorNext,
 
+    /// Advance the iterator by one and put done and value on the stack.
+    ///
+    /// Operands:
+    ///
+    /// Stack: iterator, next_function **=>** iterator, next_function, next_done, next_value
+    IteratorNextFull,
+
+    /// Close an iterator.
+    ///
+    /// Operands:
+    ///
+    /// Stack: iterator, next_function, done **=>**
+    IteratorClose,
+
     /// Consume the iterator and construct and array with all the values.
     ///
-    /// Stack: `iterator`, `next_function` **=>** `for_of_iterator`, `next_function`, `array`
+    /// Operands:
+    ///
+    /// Stack: iterator, next_function **=>** iterator, next_function, array
     IteratorToArray,
 
     /// Move to the next value in a for..in loop or jump to exit of the loop if done.
     ///
+    /// Note: next_result is only pushed if the iterator is not done.
+    ///
     /// Operands: address: `u32`
     ///
-    /// Stack: `for_in_iterator`, `next_function` **=>** `for_in_iterator`, `next_function`, `next_result` (if not done)
+    /// Stack: iterator, next_function **=>** iterator, next_function, next_result
     ForInLoopNext,
 
     /// Concat multiple stack objects into a string.
     ///
-    /// Operands: number of stack objects: `u32`
+    /// Operands: value_count: `u32`
     ///
-    /// Stack: `value1`,...`valuen` **=>** `string`
+    /// Stack: value_1,...value_n **=>** string
     ConcatToString,
 
     /// Call RequireObjectCoercible on the stack value.
     ///
-    /// Stack: `value` **=>** `value`
+    /// Operands:
+    ///
+    /// Stack: value **=>** value
     RequireObjectCoercible,
 
     /// Require the stack value to be neither null nor undefined.
     ///
-    /// Stack: `value` **=>** `value`
+    /// Operands:
+    ///
+    /// Stack: value **=>** value
     ValueNotNullOrUndefined,
 
+    /// Initialize the rest parameter value of a function from the remaining arguments.
+    ///
+    /// Operands:
+    ///
+    /// Stack: `argument_1` .. `argument_n` **=>** `array`
+    RestParameterInit,
+
+    /// Pop the remaining arguments of a function.
+    ///
+    /// Operands:
+    ///
+    /// Stack: `argument_1` .. `argument_n` **=>**
+    RestParameterPop,
+
+    /// Add one to the pop on return count.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
+    PopOnReturnAdd,
+
+    /// Subtract one from the pop on return count.
+    ///
+    /// Operands:
+    ///
+    /// Stack: **=>**
+    PopOnReturnSub,
+
     /// No-operation instruction, does nothing.
     ///
     /// Operands:
@@ -780,17 +924,21 @@ impl Opcode {
             Opcode::Neg => "Neg",
             Opcode::Inc => "Inc",
             Opcode::Dec => "Dec",
+            Opcode::DefInitArg => "DefInitArg",
             Opcode::DefVar => "DefVar",
             Opcode::DefInitVar => "DefInitVar",
             Opcode::DefLet => "DefLet",
             Opcode::DefInitLet => "DefInitLet",
             Opcode::DefInitConst => "DefInitConst",
             Opcode::GetName => "GetName",
+            Opcode::GetNameOrUndefined => "GetNameOrUndefined",
             Opcode::SetName => "SetName",
             Opcode::GetPropertyByName => "GetPropertyByName",
             Opcode::GetPropertyByValue => "GetPropertyByValue",
             Opcode::SetPropertyByName => "SetPropertyByName",
+            Opcode::DefineOwnPropertyByName => "DefineOwnPropertyByName",
             Opcode::SetPropertyByValue => "SetPropertyByValue",
+            Opcode::DefineOwnPropertyByValue => "DefineOwnPropertyByValue",
             Opcode::SetPropertyGetterByName => "SetPropertyGetterByName",
             Opcode::SetPropertyGetterByValue => "SetPropertyGetterByValue",
             Opcode::SetPropertySetterByName => "SetPropertySetterByName",
@@ -804,9 +952,12 @@ impl Opcode {
             Opcode::Throw => "Throw",
             Opcode::TryStart => "TryStart",
             Opcode::TryEnd => "TryEnd",
+            Opcode::CatchStart => "CatchStart",
+            Opcode::CatchEnd => "CatchEnd",
+            Opcode::CatchEnd2 => "CatchEnd2",
             Opcode::FinallyStart => "FinallyStart",
             Opcode::FinallyEnd => "FinallyEnd",
-            Opcode::FinallyJump => "FinallyJump",
+            Opcode::FinallySetJump => "FinallySetJump",
             Opcode::ToBoolean => "ToBoolean",
             Opcode::This => "This",
             Opcode::Case => "Case",
@@ -818,15 +969,22 @@ impl Opcode {
             Opcode::NewWithRest => "NewWithRest",
             Opcode::Return => "Return",
             Opcode::PushDeclarativeEnvironment => "PushDeclarativeEnvironment",
+            Opcode::PushFunctionEnvironment => "PushFunctionEnvironment",
             Opcode::PopEnvironment => "PopEnvironment",
             Opcode::ForInLoopInitIterator => "ForInLoopInitIterator",
             Opcode::InitIterator => "InitIterator",
             Opcode::IteratorNext => "IteratorNext",
+            Opcode::IteratorNextFull => "IteratorNextFull",
+            Opcode::IteratorClose => "IteratorClose",
             Opcode::IteratorToArray => "IteratorToArray",
             Opcode::ForInLoopNext => "ForInLoopNext",
             Opcode::ConcatToString => "ConcatToString",
             Opcode::RequireObjectCoercible => "RequireObjectCoercible",
             Opcode::ValueNotNullOrUndefined => "ValueNotNullOrUndefined",
+            Opcode::RestParameterInit => "FunctionRestParameter",
+            Opcode::RestParameterPop => "RestParameterPop",
+            Opcode::PopOnReturnAdd => "PopOnReturnAdd",
+            Opcode::PopOnReturnSub => "PopOnReturnSub",
             Opcode::Nop => "Nop",
         }
     }
diff --git a/boa_tester/src/exec/js262.rs b/boa_tester/src/exec/js262.rs
index a420fb0aa5..40a3a06845 100644
--- a/boa_tester/src/exec/js262.rs
+++ b/boa_tester/src/exec/js262.rs
@@ -1,11 +1,13 @@
 use boa::{
     builtins::JsArgs,
-    exec::Executable,
     object::{JsObject, ObjectInitializer},
     property::Attribute,
     Context, JsResult, JsValue,
 };
 
+#[cfg(not(feature = "vm"))]
+use boa::exec::Executable;
+
 /// Initializes the object in the context.
 pub(super) fn init(context: &mut Context) -> JsObject {
     let global_obj = context.global_object();
@@ -84,13 +86,16 @@ fn detach_array_buffer(
 ///
 /// Accepts a string value as its first argument and executes it as an ECMAScript script.
 fn eval_script(_this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-    // eprintln!("called $262.evalScript()");
-
     if let Some(source_text) = args.get(0).and_then(|val| val.as_string()) {
         match boa::parse(source_text.as_str(), false) {
             // TODO: check strict
             Err(e) => context.throw_type_error(format!("Uncaught Syntax Error: {}", e)),
-            Ok(script) => script.run(context),
+            #[cfg(not(feature = "vm"))]
+            Ok(statement_list) => statement_list.run(context),
+            // Calling eval here parses the code a second time.
+            // TODO: We can fix this after we have have defined the public api for the vm executer.
+            #[cfg(feature = "vm")]
+            Ok(_) => context.eval(source_text.as_str()),
         }
     } else {
         Ok(JsValue::undefined())