Implement Inline Caching (#2767)

boa_engine/src/builtins/array/mod.rs

@@ -20,7 +20,10 @@ use crate::{
     context::intrinsics::{Intrinsics, StandardConstructor, StandardConstructors},
     error::JsNativeError,
     js_string,
-    object::{internal_methods::get_prototype_from_constructor, JsObject, ObjectData, CONSTRUCTOR},
+    object::{
+        internal_methods::{get_prototype_from_constructor, InternalMethodContext},
+        JsObject, ObjectData, CONSTRUCTOR,
+    },
     property::{Attribute, PropertyDescriptor, PropertyNameKind},
     realm::Realm,
     string::common::StaticJsStrings,
@@ -349,7 +352,7 @@ impl Array {
                 .enumerable(false)
                 .configurable(false)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
 
         Ok(array)

boa_engine/src/builtins/function/tests.rs

@@ -153,7 +153,10 @@ fn closure_capture_clone() {
                         let hw = js_string!(
                             string,
                             &object
-                                .__get_own_property__(&js_string!("key").into(), context)?
+                                .__get_own_property__(
+                                    &js_string!("key").into(),
+                                    &mut context.into()
+                                )?
                                 .and_then(|prop| prop.value().cloned())
                                 .and_then(|val| val.as_string().cloned())
                                 .ok_or_else(

boa_engine/src/builtins/json/mod.rs

@@ -23,7 +23,7 @@ use crate::{
     context::intrinsics::Intrinsics,
     error::JsNativeError,
     js_string,
-    object::JsObject,
+    object::{internal_methods::InternalMethodContext, JsObject},
     property::{Attribute, PropertyNameKind},
     realm::Realm,
     string::{common::StaticJsStrings, utf16, CodePoint},
@@ -197,7 +197,7 @@ impl Json {
                     // 3. If newElement is undefined, then
                     if new_element.is_undefined() {
                         // a. Perform ? val.[[Delete]](prop).
-                        obj.__delete__(&i.into(), context)?;
+                        obj.__delete__(&i.into(), &mut InternalMethodContext::new(context))?;
                     }
                     // 4. Else,
                     else {
@@ -226,7 +226,7 @@ impl Json {
                     // 2. If newElement is undefined, then
                     if new_element.is_undefined() {
                         // a. Perform ? val.[[Delete]](P).
-                        obj.__delete__(&p.into(), context)?;
+                        obj.__delete__(&p.into(), &mut InternalMethodContext::new(context))?;
                     }
                     // 3. Else,
                     else {

boa_engine/src/builtins/object/for_in_iterator.rs

@@ -13,7 +13,7 @@ use crate::{
     context::intrinsics::Intrinsics,
     error::JsNativeError,
     js_string,
-    object::{JsObject, ObjectData},
+    object::{internal_methods::InternalMethodContext, JsObject, ObjectData},
     property::PropertyKey,
     realm::Realm,
     Context, JsResult, JsString, JsValue,
@@ -106,7 +106,8 @@ impl ForInIterator {
         let mut object = iterator.object.to_object(context)?;
         loop {
             if !iterator.object_was_visited {
-                let keys = object.__own_property_keys__(context)?;
+                let keys =
+                    object.__own_property_keys__(&mut InternalMethodContext::new(context))?;
                 for k in keys {
                     match k {
                         PropertyKey::String(ref k) => {
@@ -124,9 +125,10 @@ impl ForInIterator {
             }
             while let Some(r) = iterator.remaining_keys.pop_front() {
                 if !iterator.visited_keys.contains(&r) {
-                    if let Some(desc) =
+                    if let Some(desc) = object.__get_own_property__(
-                        object.__get_own_property__(&PropertyKey::from(r.clone()), context)?
+                        &PropertyKey::from(r.clone()),
-                    {
+                        &mut InternalMethodContext::new(context),
+                    )? {
                         iterator.visited_keys.insert(r.clone());
                         if desc.expect_enumerable() {
                             return Ok(create_iter_result_object(JsValue::new(r), false, context));

boa_engine/src/builtins/object/mod.rs

@@ -23,8 +23,8 @@ use crate::{
     js_string,
     native_function::NativeFunction,
     object::{
-        internal_methods::get_prototype_from_constructor, FunctionObjectBuilder, IntegrityLevel,
+        internal_methods::{get_prototype_from_constructor, InternalMethodContext},
-        JsObject, ObjectData, ObjectKind,
+        FunctionObjectBuilder, IntegrityLevel, JsObject, ObjectData, ObjectKind,
     },
     property::{Attribute, PropertyDescriptor, PropertyKey, PropertyNameKind},
     realm::Realm,
@@ -211,7 +211,7 @@ impl Object {
         let obj = this.to_object(context)?;
 
         // 2. Return ? O.[[GetPrototypeOf]]().
-        let proto = obj.__get_prototype_of__(context)?;
+        let proto = obj.__get_prototype_of__(&mut InternalMethodContext::new(context))?;
 
         Ok(proto.map_or(JsValue::Null, JsValue::new))
     }
@@ -248,7 +248,8 @@ impl Object {
         };
 
         // 4. Let status be ? O.[[SetPrototypeOf]](proto).
-        let status = object.__set_prototype_of__(proto, context)?;
+        let status =
+            object.__set_prototype_of__(proto, &mut InternalMethodContext::new(context))?;
 
         // 5. If status is false, throw a TypeError exception.
         if !status {
@@ -371,7 +372,8 @@ impl Object {
         // 3. Repeat
         loop {
             // a. Let desc be ? O.[[GetOwnProperty]](key).
-            let desc = obj.__get_own_property__(&key, context)?;
+
+            let desc = obj.__get_own_property__(&key, &mut InternalMethodContext::new(context))?;
 
             // b. If desc is not undefined, then
             if let Some(current_desc) = desc {
@@ -383,7 +385,7 @@ impl Object {
                     Ok(JsValue::undefined())
                 };
             }
-            match obj.__get_prototype_of__(context)? {
+            match obj.__get_prototype_of__(&mut InternalMethodContext::new(context))? {
                 // c. Set O to ? O.[[GetPrototypeOf]]().
                 Some(o) => obj = o,
                 // d. If O is null, return undefined.
@@ -415,7 +417,8 @@ impl Object {
         // 3. Repeat
         loop {
             // a. Let desc be ? O.[[GetOwnProperty]](key).
-            let desc = obj.__get_own_property__(&key, context)?;
+
+            let desc = obj.__get_own_property__(&key, &mut InternalMethodContext::new(context))?;
 
             // b. If desc is not undefined, then
             if let Some(current_desc) = desc {
@@ -427,7 +430,7 @@ impl Object {
                     Ok(JsValue::undefined())
                 };
             }
-            match obj.__get_prototype_of__(context)? {
+            match obj.__get_prototype_of__(&mut InternalMethodContext::new(context))? {
                 // c. Set O to ? O.[[GetPrototypeOf]]().
                 Some(o) => obj = o,
                 // d. If O is null, return undefined.
@@ -496,7 +499,8 @@ impl Object {
         let key = args.get_or_undefined(1).to_property_key(context)?;
 
         // 3. Let desc be ? obj.[[GetOwnProperty]](key).
-        let desc = obj.__get_own_property__(&key, context)?;
+
+        let desc = obj.__get_own_property__(&key, &mut InternalMethodContext::new(context))?;
 
         // 4. Return FromPropertyDescriptor(desc).
         Ok(Self::from_property_descriptor(desc, context))
@@ -521,7 +525,7 @@ impl Object {
         let obj = args.get_or_undefined(0).to_object(context)?;
 
         // 2. Let ownKeys be ? obj.[[OwnPropertyKeys]]().
-        let own_keys = obj.__own_property_keys__(context)?;
+        let own_keys = obj.__own_property_keys__(&mut InternalMethodContext::new(context))?;
 
         // 3. Let descriptors be OrdinaryObjectCreate(%Object.prototype%).
         let descriptors = JsObject::with_object_proto(context.intrinsics());
@@ -529,7 +533,8 @@ impl Object {
         // 4. For each element key of ownKeys, do
         for key in own_keys {
             // a. Let desc be ? obj.[[GetOwnProperty]](key).
-            let desc = obj.__get_own_property__(&key, context)?;
+
+            let desc = obj.__get_own_property__(&key, &mut InternalMethodContext::new(context))?;
 
             // b. Let descriptor be FromPropertyDescriptor(desc).
             let descriptor = Self::from_property_descriptor(desc, context);
@@ -642,7 +647,7 @@ impl Object {
 
         // 2. Return ? obj.[[GetPrototypeOf]]().
         Ok(obj
-            .__get_prototype_of__(context)?
+            .__get_prototype_of__(&mut InternalMethodContext::new(context))?
             .map_or(JsValue::Null, JsValue::new))
     }
 
@@ -693,7 +698,7 @@ impl Object {
         };
 
         // 4. Let status be ? O.[[SetPrototypeOf]](proto).
-        let status = obj.__set_prototype_of__(proto, context)?;
+        let status = obj.__set_prototype_of__(proto, &mut InternalMethodContext::new(context))?;
 
         // 5. If status is false, throw a TypeError exception.
         if !status {
@@ -931,9 +936,10 @@ impl Object {
         };
 
         let key = key.to_property_key(context)?;
+
         let own_prop = this
             .to_object(context)?
-            .__get_own_property__(&key, context)?;
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?;
 
         own_prop
             .as_ref()
@@ -972,11 +978,14 @@ impl Object {
                     .to_object(context)
                     .expect("this ToObject call must not fail");
                 // 3.a.ii. Let keys be ? from.[[OwnPropertyKeys]]().
-                let keys = from.__own_property_keys__(context)?;
+                let keys = from.__own_property_keys__(&mut InternalMethodContext::new(context))?;
                 // 3.a.iii. For each element nextKey of keys, do
                 for key in keys {
                     // 3.a.iii.1. Let desc be ? from.[[GetOwnProperty]](nextKey).
-                    if let Some(desc) = from.__get_own_property__(&key, context)? {
+
+                    if let Some(desc) =
+                        from.__get_own_property__(&key, &mut InternalMethodContext::new(context))?
+                    {
                         // 3.a.iii.2. If desc is not undefined and desc.[[Enumerable]] is true, then
                         if desc.expect_enumerable() {
                             // 3.a.iii.2.a. Let propValue be ? Get(from, nextKey).
@@ -1187,7 +1196,7 @@ impl Object {
 
         if let Some(o) = o.as_object() {
             // 2. Let status be ? O.[[PreventExtensions]]().
-            let status = o.__prevent_extensions__(context)?;
+            let status = o.__prevent_extensions__(&mut InternalMethodContext::new(context))?;
             // 3. If status is false, throw a TypeError exception.
             if !status {
                 return Err(JsNativeError::typ()
@@ -1444,7 +1453,7 @@ fn object_define_properties(
     let props = &props.to_object(context)?;
 
     // 3. Let keys be ? props.[[OwnPropertyKeys]]().
-    let keys = props.__own_property_keys__(context)?;
+    let keys = props.__own_property_keys__(&mut InternalMethodContext::new(context))?;
 
     // 4. Let descriptors be a new empty List.
     let mut descriptors: Vec<(PropertyKey, PropertyDescriptor)> = Vec::new();
@@ -1453,7 +1462,10 @@ fn object_define_properties(
     for next_key in keys {
         // a. Let propDesc be ? props.[[GetOwnProperty]](nextKey).
         // b. If propDesc is not undefined and propDesc.[[Enumerable]] is true, then
-        if let Some(prop_desc) = props.__get_own_property__(&next_key, context)? {
+
+        if let Some(prop_desc) =
+            props.__get_own_property__(&next_key, &mut InternalMethodContext::new(context))?
+        {
             if prop_desc.expect_enumerable() {
                 // i. Let descObj be ? Get(props, nextKey).
                 let desc_obj = props.get(next_key.clone(), context)?;
@@ -1501,7 +1513,7 @@ fn get_own_property_keys(
     let obj = o.to_object(context)?;
 
     // 2. Let keys be ? obj.[[OwnPropertyKeys]]().
-    let keys = obj.__own_property_keys__(context)?;
+    let keys = obj.__own_property_keys__(&mut InternalMethodContext::new(context))?;
 
     // 3. Let nameList be a new empty List.
     // 4. For each element nextKey of keys, do

boa_engine/src/builtins/reflect/mod.rs

@@ -16,7 +16,7 @@ use crate::{
     context::intrinsics::Intrinsics,
     error::JsNativeError,
     js_string,
-    object::JsObject,
+    object::{internal_methods::InternalMethodContext, JsObject},
     property::Attribute,
     realm::Realm,
     string::common::StaticJsStrings,
@@ -166,7 +166,11 @@ impl Reflect {
             .into();
 
         target
-            .__define_own_property__(&key, prop_desc.to_property_descriptor(context)?, context)
+            .__define_own_property__(
+                &key,
+                prop_desc.to_property_descriptor(context)?,
+                &mut InternalMethodContext::new(context),
+            )
             .map(Into::into)
     }
 
@@ -189,7 +193,9 @@ impl Reflect {
             .ok_or_else(|| JsNativeError::typ().with_message("target must be an object"))?;
         let key = args.get_or_undefined(1).to_property_key(context)?;
 
-        Ok(target.__delete__(&key, context)?.into())
+        Ok(target
+            .__delete__(&key, &mut InternalMethodContext::new(context))?
+            .into())
     }
 
     /// Gets a property of an object.
@@ -215,7 +221,8 @@ impl Reflect {
             .cloned()
             .unwrap_or_else(|| target.clone().into());
         // 4. Return ? target.[[Get]](key, receiver).
-        target.__get__(&key, receiver, context)
+
+        target.__get__(&key, receiver, &mut InternalMethodContext::new(context))
     }
 
     /// Gets a property of an object.
@@ -264,7 +271,7 @@ impl Reflect {
             .and_then(JsValue::as_object)
             .ok_or_else(|| JsNativeError::typ().with_message("target must be an object"))?;
         Ok(target
-            .__get_prototype_of__(context)?
+            .__get_prototype_of__(&mut InternalMethodContext::new(context))?
             .map_or(JsValue::Null, JsValue::new))
     }
 
@@ -285,7 +292,10 @@ impl Reflect {
             .get(1)
             .unwrap_or(&JsValue::undefined())
             .to_property_key(context)?;
-        Ok(target.__has_property__(&key, context)?.into())
+
+        Ok(target
+            .__has_property__(&key, &mut InternalMethodContext::new(context))?
+            .into())
     }
 
     /// Returns `true` if the object is extensible, `false` otherwise.
@@ -305,7 +315,9 @@ impl Reflect {
             .get(0)
             .and_then(JsValue::as_object)
             .ok_or_else(|| JsNativeError::typ().with_message("target must be an object"))?;
-        Ok(target.__is_extensible__(context)?.into())
+        Ok(target
+            .__is_extensible__(&mut InternalMethodContext::new(context))?
+            .into())
     }
 
     /// Returns an array of object own property keys.
@@ -327,7 +339,7 @@ impl Reflect {
             .ok_or_else(|| JsNativeError::typ().with_message("target must be an object"))?;
 
         let keys: Vec<JsValue> = target
-            .__own_property_keys__(context)?
+            .__own_property_keys__(&mut InternalMethodContext::new(context))?
             .into_iter()
             .map(Into::into)
             .collect();
@@ -353,7 +365,9 @@ impl Reflect {
             .and_then(JsValue::as_object)
             .ok_or_else(|| JsNativeError::typ().with_message("target must be an object"))?;
 
-        Ok(target.__prevent_extensions__(context)?.into())
+        Ok(target
+            .__prevent_extensions__(&mut InternalMethodContext::new(context))?
+            .into())
     }
 
     /// Sets a property of an object.
@@ -375,8 +389,14 @@ impl Reflect {
             .get(3)
             .cloned()
             .unwrap_or_else(|| target.clone().into());
+
         Ok(target
-            .__set__(key, value.clone(), receiver, context)?
+            .__set__(
+                key,
+                value.clone(),
+                receiver,
+                &mut InternalMethodContext::new(context),
+            )?
             .into())
     }
 
@@ -406,6 +426,8 @@ impl Reflect {
                     .into())
             }
         };
-        Ok(target.__set_prototype_of__(proto, context)?.into())
+        Ok(target
+            .__set_prototype_of__(proto, &mut InternalMethodContext::new(context))?
+            .into())
     }
 }

boa_engine/src/builtins/temporal/calendar/mod.rs

@@ -1181,7 +1181,7 @@ pub(crate) fn to_temporal_calendar_slot_value(
 fn object_implements_calendar_protocol(calendar_like: &JsObject, context: &mut Context) -> bool {
     CALENDAR_PROTOCOL_METHODS.into_iter().all(|method| {
         calendar_like
-            .__has_property__(&JsString::from(method).into(), context)
+            .__has_property__(&JsString::from(method).into(), &mut context.into())
             .unwrap_or(false)
     })
 }

boa_engine/src/builtins/temporal/calendar/object.rs

@@ -847,7 +847,7 @@ impl CalendarProtocol for CustomRuntimeCalendar {
             .__get__(
                 &PropertyKey::from(utf16!("id")),
                 JsValue::undefined(),
-                context,
+                &mut context.into(),
             )
             .expect("method must exist on a object that implements the CalendarProtocol.");
 

boa_engine/src/builtins/temporal/mod.rs

@@ -597,7 +597,7 @@ pub(crate) fn copy_data_properties(
         // c. If excluded is false, then
         if !excluded {
             // i. Let desc be ? from.[[GetOwnProperty]](nextKey).
-            let desc = from.__get_own_property__(&next_key, context)?;
+            let desc = from.__get_own_property__(&next_key, &mut context.into())?;
             // ii. If desc is not undefined and desc.[[Enumerable]] is true, then
             match desc {
                 Some(d)

boa_engine/src/builtins/typed_array/builtin.rs

@@ -2262,7 +2262,7 @@ impl BuiltinTypedArray {
             let target_index = target_offset + k;
 
             // d. Perform ? IntegerIndexedElementSet(target, targetIndex, value).
-            integer_indexed_element_set(target, target_index as f64, &value, context)?;
+            integer_indexed_element_set(target, target_index as f64, &value, &mut context.into())?;
 
             // e. Set k to k + 1.
         }

boa_engine/src/bytecompiler/declaration/declaration_pattern.rs

@@ -39,11 +39,7 @@ impl ByteCompiler<'_> {
                             self.emit_opcode(Opcode::Dup);
                             match name {
                                 PropertyName::Literal(name) => {
-                                    let index = self.get_or_insert_name((*name).into());
+                                    self.emit_get_property_by_name(*name);
-                                    self.emit_with_varying_operand(
-                                        Opcode::GetPropertyByName,
-                                        index,
-                                    );
                                 }
                                 PropertyName::Computed(node) => {
                                     self.compile_expr(node, true);
@@ -123,11 +119,7 @@ impl ByteCompiler<'_> {
                             self.emit_opcode(Opcode::Dup);
                             match name {
                                 PropertyName::Literal(name) => {
-                                    let index = self.get_or_insert_name((*name).into());
+                                    self.emit_get_property_by_name(*name);
-                                    self.emit_with_varying_operand(
-                                        Opcode::GetPropertyByName,
-                                        index,
-                                    );
                                 }
                                 PropertyName::Computed(node) => {
                                     self.compile_expr(node, true);
@@ -166,11 +158,7 @@ impl ByteCompiler<'_> {
                             self.emit_opcode(Opcode::Dup);
                             match name {
                                 PropertyName::Literal(name) => {
-                                    let index = self.get_or_insert_name((*name).into());
+                                    self.emit_get_property_by_name(*name);
-                                    self.emit_with_varying_operand(
-                                        Opcode::GetPropertyByName,
-                                        index,
-                                    );
                                 }
                                 PropertyName::Computed(node) => {
                                     self.compile_expr(node, true);

boa_engine/src/bytecompiler/expression/assign.rs

@@ -99,13 +99,12 @@ impl ByteCompiler<'_> {
                 Access::Property { access } => match access {
                     PropertyAccess::Simple(access) => match access.field() {
                         PropertyAccessField::Const(name) => {
-                            let index = self.get_or_insert_name((*name).into());
                             self.compile_expr(access.target(), true);
                             self.emit_opcode(Opcode::Dup);
                             self.emit_opcode(Opcode::Dup);
                             self.emit_opcode(Opcode::Dup);
 
-                            self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
+                            self.emit_get_property_by_name(*name);
                             if short_circuit {
                                 pop_count = 2;
                                 early_exit = Some(self.emit_opcode_with_operand(opcode));
@@ -115,7 +114,7 @@ impl ByteCompiler<'_> {
                                 self.emit_opcode(opcode);
                             }
 
-                            self.emit_with_varying_operand(Opcode::SetPropertyByName, index);
+                            self.emit_set_property_by_name(*name);
                             if !use_expr {
                                 self.emit_opcode(Opcode::Pop);
                             }
@@ -165,14 +164,13 @@ impl ByteCompiler<'_> {
                     }
                     PropertyAccess::Super(access) => match access.field() {
                         PropertyAccessField::Const(name) => {
-                            let index = self.get_or_insert_name((*name).into());
                             self.emit_opcode(Opcode::Super);
                             self.emit_opcode(Opcode::Dup);
                             self.emit_opcode(Opcode::This);
                             self.emit_opcode(Opcode::Swap);
                             self.emit_opcode(Opcode::This);
 
-                            self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
+                            self.emit_get_property_by_name(*name);
                             if short_circuit {
                                 pop_count = 2;
                                 early_exit = Some(self.emit_opcode_with_operand(opcode));
@@ -182,7 +180,7 @@ impl ByteCompiler<'_> {
                                 self.emit_opcode(opcode);
                             }
 
-                            self.emit_with_varying_operand(Opcode::SetPropertyByName, index);
+                            self.emit_set_property_by_name(*name);
                             if !use_expr {
                                 self.emit_opcode(Opcode::Pop);
                             }

boa_engine/src/bytecompiler/expression/mod.rs

@@ -239,8 +239,7 @@ impl ByteCompiler<'_> {
                         self.emit_opcode(Opcode::Dup);
                         match access.field() {
                             PropertyAccessField::Const(field) => {
-                                let index = self.get_or_insert_name((*field).into());
+                                self.emit_get_property_by_name(*field);
-                                self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
                             }
                             PropertyAccessField::Expr(field) => {
                                 self.compile_expr(field, true);

boa_engine/src/bytecompiler/expression/update.rs

@@ -63,19 +63,18 @@ impl ByteCompiler<'_> {
             Access::Property { access } => match access {
                 PropertyAccess::Simple(access) => match access.field() {
                     PropertyAccessField::Const(name) => {
-                        let index = self.get_or_insert_name((*name).into());
                         self.compile_expr(access.target(), true);
                         self.emit_opcode(Opcode::Dup);
                         self.emit_opcode(Opcode::Dup);
                         self.emit_opcode(Opcode::Dup);
 
-                        self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
+                        self.emit_get_property_by_name(*name);
                         self.emit_opcode(opcode);
                         if post {
                             self.emit(Opcode::RotateRight, &[Operand::U8(4)]);
                         }
 
-                        self.emit_with_varying_operand(Opcode::SetPropertyByName, index);
+                        self.emit_set_property_by_name(*name);
                         if post {
                             self.emit_opcode(Opcode::Pop);
                         }
@@ -117,20 +116,19 @@ impl ByteCompiler<'_> {
                 }
                 PropertyAccess::Super(access) => match access.field() {
                     PropertyAccessField::Const(name) => {
-                        let index = self.get_or_insert_name((*name).into());
                         self.emit_opcode(Opcode::Super);
                         self.emit_opcode(Opcode::Dup);
                         self.emit_opcode(Opcode::This);
                         self.emit_opcode(Opcode::Swap);
                         self.emit_opcode(Opcode::This);
 
-                        self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
+                        self.emit_get_property_by_name(*name);
                         self.emit_opcode(opcode);
                         if post {
                             self.emit(Opcode::RotateRight, &[Operand::U8(3)]);
                         }
 
-                        self.emit_with_varying_operand(Opcode::SetPropertyByName, index);
+                        self.emit_set_property_by_name(*name);
                         if post {
                             self.emit_opcode(Opcode::Pop);
                         }

boa_engine/src/bytecompiler/mod.rs

@@ -18,8 +18,8 @@ use crate::{
     environments::{BindingLocator, BindingLocatorError, CompileTimeEnvironment},
     js_string,
     vm::{
-        BindingOpcode, CodeBlock, CodeBlockFlags, Constant, GeneratorResumeKind, Handler, Opcode,
+        BindingOpcode, CodeBlock, CodeBlockFlags, Constant, GeneratorResumeKind, Handler,
-        VaryingOperandKind,
+        InlineCache, Opcode, VaryingOperandKind,
     },
     Context, JsBigInt, JsString,
 };
@@ -279,6 +279,7 @@ pub struct ByteCompiler<'ctx> {
     current_stack_value_count: u32,
     pub(crate) code_block_flags: CodeBlockFlags,
     handlers: ThinVec<Handler>,
+    pub(crate) ic: Vec<InlineCache>,
     literals_map: FxHashMap<Literal, u32>,
     names_map: FxHashMap<Identifier, u32>,
     bindings_map: FxHashMap<BindingLocator, u32>,
@@ -330,6 +331,7 @@ impl<'ctx> ByteCompiler<'ctx> {
             current_stack_value_count: 2,
             code_block_flags,
             handlers: ThinVec::default(),
+            ic: Vec::default(),
 
             literals_map: FxHashMap::default(),
             names_map: FxHashMap::default(),
@@ -540,6 +542,29 @@ impl<'ctx> ByteCompiler<'ctx> {
     fn emit_i64(&mut self, value: i64) {
         self.emit_u64(value as u64);
     }
+    fn emit_get_property_by_name(&mut self, ident: Sym) {
+        let ic_index = self.ic.len() as u32;
+
+        let name_index = self.get_or_insert_name(Identifier::new(ident));
+        let Constant::String(ref name) = self.constants[name_index as usize].clone() else {
+            unreachable!("there should be a string at index")
+        };
+        self.ic.push(InlineCache::new(name.clone()));
+
+        self.emit_with_varying_operand(Opcode::GetPropertyByName, ic_index);
+    }
+
+    fn emit_set_property_by_name(&mut self, ident: Sym) {
+        let ic_index = self.ic.len() as u32;
+
+        let name_index = self.get_or_insert_name(Identifier::new(ident));
+        let Constant::String(ref name) = self.constants[name_index as usize].clone() else {
+            unreachable!("there should be a string at index")
+        };
+        self.ic.push(InlineCache::new(name.clone()));
+
+        self.emit_with_varying_operand(Opcode::SetPropertyByName, ic_index);
+    }
 
     fn emit_u64(&mut self, value: u64) {
         self.bytecode.extend(value.to_ne_bytes());
@@ -698,7 +723,7 @@ impl<'ctx> ByteCompiler<'ctx> {
 
         // This is done to avoid unneeded bounds checks.
         assert!(self.bytecode.len() > index + U32_SIZE && usize::MAX - U32_SIZE >= index);
-        self.bytecode[index + 1..=index + U32_SIZE].copy_from_slice(bytes.as_slice());
+        self.bytecode[index + 1..=index + U32_SIZE].clone_from_slice(bytes.as_slice());
     }
 
     fn patch_jump(&mut self, label: Label) {
@@ -721,10 +746,9 @@ impl<'ctx> ByteCompiler<'ctx> {
             Access::Property { access } => match access {
                 PropertyAccess::Simple(access) => match access.field() {
                     PropertyAccessField::Const(name) => {
-                        let index = self.get_or_insert_name((*name).into());
                         self.compile_expr(access.target(), true);
                         self.emit_opcode(Opcode::Dup);
-                        self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
+                        self.emit_get_property_by_name(*name);
                     }
                     PropertyAccessField::Expr(expr) => {
                         self.compile_expr(access.target(), true);
@@ -740,10 +764,10 @@ impl<'ctx> ByteCompiler<'ctx> {
                 }
                 PropertyAccess::Super(access) => match access.field() {
                     PropertyAccessField::Const(field) => {
-                        let index = self.get_or_insert_name((*field).into());
                         self.emit_opcode(Opcode::Super);
                         self.emit_opcode(Opcode::This);
-                        self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
+
+                        self.emit_get_property_by_name(*field);
                     }
                     PropertyAccessField::Expr(expr) => {
                         self.emit_opcode(Opcode::Super);
@@ -818,9 +842,8 @@ impl<'ctx> ByteCompiler<'ctx> {
                         self.compile_expr(access.target(), true);
                         self.emit_opcode(Opcode::Dup);
                         expr_fn(self, 2);
-                        let index = self.get_or_insert_name((*name).into());
 
-                        self.emit_with_varying_operand(Opcode::SetPropertyByName, index);
+                        self.emit_set_property_by_name(*name);
                         if !use_expr {
                             self.emit_opcode(Opcode::Pop);
                         }
@@ -850,8 +873,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                         self.emit_opcode(Opcode::Super);
                         self.emit_opcode(Opcode::This);
                         expr_fn(self, 1);
-                        let index = self.get_or_insert_name((*name).into());
+                        self.emit_set_property_by_name(*name);
-                        self.emit_with_varying_operand(Opcode::SetPropertyByName, index);
                         if !use_expr {
                             self.emit_opcode(Opcode::Pop);
                         }
@@ -958,8 +980,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 self.emit_opcode(Opcode::Dup);
                 match access.field() {
                     PropertyAccessField::Const(field) => {
-                        let index = self.get_or_insert_name((*field).into());
+                        self.emit_get_property_by_name(*field);
-                        self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
                     }
                     PropertyAccessField::Expr(field) => {
                         self.compile_expr(field, true);
@@ -979,8 +1000,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 self.emit_opcode(Opcode::This);
                 match access.field() {
                     PropertyAccessField::Const(field) => {
-                        let index = self.get_or_insert_name((*field).into());
+                        self.emit_get_property_by_name(*field);
-                        self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
                     }
                     PropertyAccessField::Expr(expr) => {
                         self.compile_expr(expr, true);
@@ -1065,8 +1085,7 @@ impl<'ctx> ByteCompiler<'ctx> {
                 self.emit_opcode(Opcode::Dup);
                 match field {
                     PropertyAccessField::Const(name) => {
-                        let index = self.get_or_insert_name((*name).into());
+                        self.emit_get_property_by_name(*name);
-                        self.emit_with_varying_operand(Opcode::GetPropertyByName, index);
                     }
                     PropertyAccessField::Expr(expr) => {
                         self.compile_expr(expr, true);
@@ -1512,6 +1531,7 @@ impl<'ctx> ByteCompiler<'ctx> {
             bindings: self.bindings.into_boxed_slice(),
             handlers: self.handlers,
             flags: Cell::new(self.code_block_flags),
+            ic: self.ic.into_boxed_slice(),
         }
     }
 

boa_engine/src/context/mod.rs

@@ -616,7 +616,7 @@ impl Context {
 
         // 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).
         let name = name.clone().into();
-        let existing_prop = global_object.__get_own_property__(&name, self)?;
+        let existing_prop = global_object.__get_own_property__(&name, &mut self.into())?;
 
         // 4. If existingProp is undefined, return ? IsExtensible(globalObject).
         let Some(existing_prop) = existing_prop else {
@@ -723,7 +723,8 @@ impl Context {
         let global_object = self.realm().global_object().clone();
 
         // 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).
-        let existing_prop = global_object.__get_own_property__(&name.clone().into(), self)?;
+        let existing_prop =
+            global_object.__get_own_property__(&name.clone().into(), &mut self.into())?;
 
         // 4. If existingProp is undefined or existingProp.[[Configurable]] is true, then
         let desc = if existing_prop.is_none()
@@ -770,7 +771,7 @@ impl Context {
 
         // 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).
         let name = name.clone().into();
-        let existing_prop = global_object.__get_own_property__(&name, self)?;
+        let existing_prop = global_object.__get_own_property__(&name, &mut self.into())?;
 
         // 4. If existingProp is undefined, return false.
         let Some(existing_prop) = existing_prop else {

boa_engine/src/environments/runtime/mod.rs

@@ -2,7 +2,7 @@ use std::rc::Rc;
 
 use crate::{
     environments::CompileTimeEnvironment,
-    object::{JsObject, PrivateName},
+    object::{internal_methods::InternalMethodContext, JsObject, PrivateName},
     Context, JsResult, JsString, JsSymbol, JsValue,
 };
 use boa_gc::{empty_trace, Finalize, Gc, Trace};
@@ -630,7 +630,8 @@ impl Context {
     pub(crate) fn delete_binding(&mut self, locator: &BindingLocator) -> JsResult<bool> {
         if locator.is_global() {
             let key = locator.name().clone();
-            self.global_object().__delete__(&key.into(), self)
+            self.global_object()
+                .__delete__(&key.into(), &mut self.into())
         } else {
             match self.environment_expect(locator.environment_index) {
                 Environment::Declarative(_) => Ok(false),
@@ -638,7 +639,7 @@ impl Context {
                     let obj = obj.clone();
                     let key = locator.name().clone();
 
-                    obj.__delete__(&key.into(), self)
+                    obj.__delete__(&key.into(), &mut InternalMethodContext::new(self))
                 }
             }
         }

boa_engine/src/object/internal_methods/arguments.rs

@@ -1,10 +1,10 @@
 use crate::{
     object::JsObject,
     property::{DescriptorKind, PropertyDescriptor, PropertyKey},
-    Context, JsResult, JsValue,
+    JsResult, JsValue,
 };
 
-use super::{InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
+use super::{InternalMethodContext, InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
 
 pub(crate) static ARGUMENTS_EXOTIC_INTERNAL_METHODS: InternalObjectMethods =
     InternalObjectMethods {
@@ -25,7 +25,7 @@ pub(crate) static ARGUMENTS_EXOTIC_INTERNAL_METHODS: InternalObjectMethods =
 pub(crate) fn arguments_exotic_get_own_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<Option<PropertyDescriptor>> {
     // 1. Let desc be OrdinaryGetOwnProperty(args, P).
     // 2. If desc is undefined, return desc.
@@ -70,7 +70,7 @@ pub(crate) fn arguments_exotic_define_own_property(
     obj: &JsObject,
     key: &PropertyKey,
     desc: PropertyDescriptor,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 2. Let isMapped be HasOwnProperty(map, P).
     let mapped = if let &PropertyKey::Index(index) = &key {
@@ -161,7 +161,7 @@ pub(crate) fn arguments_exotic_get(
     obj: &JsObject,
     key: &PropertyKey,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<JsValue> {
     if let PropertyKey::Index(index) = key {
         // 1. Let map be args.[[ParameterMap]].
@@ -194,7 +194,7 @@ pub(crate) fn arguments_exotic_set(
     key: PropertyKey,
     value: JsValue,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. If SameValue(args, Receiver) is false, then
     // a. Let isMapped be false.
@@ -226,7 +226,7 @@ pub(crate) fn arguments_exotic_set(
 pub(crate) fn arguments_exotic_delete(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 3. Let result be ? OrdinaryDelete(args, P).
     let result = super::ordinary_delete(obj, key, context)?;

boa_engine/src/object/internal_methods/array.rs

@@ -3,10 +3,10 @@ use crate::{
     object::JsObject,
     property::{PropertyDescriptor, PropertyKey},
     string::utf16,
-    Context, JsResult,
+    JsResult,
 };
 
-use super::{InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
+use super::{InternalMethodContext, InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
 
 /// Definitions of the internal object methods for array exotic objects.
 ///
@@ -29,7 +29,7 @@ pub(crate) fn array_exotic_define_own_property(
     obj: &JsObject,
     key: &PropertyKey,
     desc: PropertyDescriptor,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. Assert: IsPropertyKey(P) is true.
     match key {
@@ -111,7 +111,7 @@ pub(crate) fn array_exotic_define_own_property(
 fn array_set_length(
     obj: &JsObject,
     desc: PropertyDescriptor,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. If Desc.[[Value]] is absent, then
     let Some(new_len_val) = desc.value() else {

boa_engine/src/object/internal_methods/integer_indexed.rs

@@ -9,7 +9,7 @@ use crate::{
     Context, JsResult, JsString, JsValue,
 };
 
-use super::{InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
+use super::{InternalMethodContext, InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
 
 /// Definitions of the internal object methods for integer-indexed exotic objects.
 ///
@@ -62,7 +62,7 @@ fn canonical_numeric_index_string(argument: &JsString) -> Option<f64> {
 pub(crate) fn integer_indexed_exotic_get_own_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<Option<PropertyDescriptor>> {
     let p = match key {
         PropertyKey::String(key) => {
@@ -104,7 +104,7 @@ pub(crate) fn integer_indexed_exotic_get_own_property(
 pub(crate) fn integer_indexed_exotic_has_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     let p = match key {
         PropertyKey::String(key) => {
@@ -135,7 +135,7 @@ pub(crate) fn integer_indexed_exotic_define_own_property(
     obj: &JsObject,
     key: &PropertyKey,
     desc: PropertyDescriptor,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     let p = match key {
         PropertyKey::String(key) => {
@@ -197,7 +197,7 @@ pub(crate) fn integer_indexed_exotic_get(
     obj: &JsObject,
     key: &PropertyKey,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<JsValue> {
     let p = match key {
         PropertyKey::String(key) => {
@@ -230,7 +230,7 @@ pub(crate) fn integer_indexed_exotic_set(
     key: PropertyKey,
     value: JsValue,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     let p = match &key {
         PropertyKey::String(key) => {
@@ -272,7 +272,7 @@ pub(crate) fn integer_indexed_exotic_set(
 pub(crate) fn integer_indexed_exotic_delete(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     let p = match &key {
         PropertyKey::String(key) => {
@@ -388,7 +388,7 @@ pub(crate) fn integer_indexed_element_set(
     obj: &JsObject,
     index: f64,
     value: &JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<()> {
     let obj_borrow = obj.borrow();
     let inner = obj_borrow.as_typed_array().expect(

boa_engine/src/object/internal_methods/mod.rs

@@ -5,7 +5,12 @@
 //!
 //! [spec]: https://tc39.es/ecma262/#sec-ordinary-object-internal-methods-and-internal-slots
 
-use super::{JsPrototype, PROTOTYPE};
+use std::ops::{Deref, DerefMut};
+
+use super::{
+    shape::slot::{Slot, SlotAttributes},
+    JsPrototype, PROTOTYPE,
+};
 use crate::{
     context::intrinsics::{StandardConstructor, StandardConstructors},
     object::JsObject,
@@ -28,6 +33,52 @@ pub(super) mod string;
 pub(crate) use array::ARRAY_EXOTIC_INTERNAL_METHODS;
 pub(crate) use integer_indexed::integer_indexed_element_set;
 
+/// A lightweight wrapper around [`Context`] used in [`InternalObjectMethods`].
+#[derive(Debug)]
+pub(crate) struct InternalMethodContext<'ctx> {
+    context: &'ctx mut Context,
+    slot: Slot,
+}
+
+impl<'ctx> InternalMethodContext<'ctx> {
+    /// Create a new [`InternalMethodContext`].
+    pub(crate) fn new(context: &'ctx mut Context) -> Self {
+        Self {
+            context,
+            slot: Slot::new(),
+        }
+    }
+
+    /// Gets the [`Slot`] associated with this [`InternalMethodContext`].
+    #[inline]
+    pub(crate) fn slot(&mut self) -> &mut Slot {
+        &mut self.slot
+    }
+}
+
+impl Deref for InternalMethodContext<'_> {
+    type Target = Context;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        self.context
+    }
+}
+
+impl DerefMut for InternalMethodContext<'_> {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.context
+    }
+}
+
+impl<'context> From<&'context mut Context> for InternalMethodContext<'context> {
+    #[inline]
+    fn from(context: &'context mut Context) -> Self {
+        Self::new(context)
+    }
+}
+
 impl JsObject {
     /// Internal method `[[GetPrototypeOf]]`
     ///
@@ -97,7 +148,7 @@ impl JsObject {
     pub(crate) fn __get_own_property__(
         &self,
         key: &PropertyKey,
-        context: &mut Context,
+        context: &mut InternalMethodContext<'_>,
     ) -> JsResult<Option<PropertyDescriptor>> {
         let _timer = Profiler::global().start_event("Object::__get_own_property__", "object");
         (self.vtable().__get_own_property__)(self, key, context)
@@ -115,7 +166,7 @@ impl JsObject {
         &self,
         key: &PropertyKey,
         desc: PropertyDescriptor,
-        context: &mut Context,
+        context: &mut InternalMethodContext<'_>,
     ) -> JsResult<bool> {
         let _timer = Profiler::global().start_event("Object::__define_own_property__", "object");
         (self.vtable().__define_own_property__)(self, key, desc, context)
@@ -132,7 +183,7 @@ impl JsObject {
     pub(crate) fn __has_property__(
         &self,
         key: &PropertyKey,
-        context: &mut Context,
+        context: &mut InternalMethodContext<'_>,
     ) -> JsResult<bool> {
         let _timer = Profiler::global().start_event("Object::__has_property__", "object");
         (self.vtable().__has_property__)(self, key, context)
@@ -150,7 +201,7 @@ impl JsObject {
         &self,
         key: &PropertyKey,
         receiver: JsValue,
-        context: &mut Context,
+        context: &mut InternalMethodContext<'_>,
     ) -> JsResult<JsValue> {
         let _timer = Profiler::global().start_event("Object::__get__", "object");
         (self.vtable().__get__)(self, key, receiver, context)
@@ -169,7 +220,7 @@ impl JsObject {
         key: PropertyKey,
         value: JsValue,
         receiver: JsValue,
-        context: &mut Context,
+        context: &mut InternalMethodContext<'_>,
     ) -> JsResult<bool> {
         let _timer = Profiler::global().start_event("Object::__set__", "object");
         (self.vtable().__set__)(self, key, value, receiver, context)
@@ -183,7 +234,11 @@ impl JsObject {
     ///  - [ECMAScript reference][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-ordinary-object-internal-methods-and-internal-slots-delete-p
-    pub(crate) fn __delete__(&self, key: &PropertyKey, context: &mut Context) -> JsResult<bool> {
+    pub(crate) fn __delete__(
+        &self,
+        key: &PropertyKey,
+        context: &mut InternalMethodContext<'_>,
+    ) -> JsResult<bool> {
         let _timer = Profiler::global().start_event("Object::__delete__", "object");
         (self.vtable().__delete__)(self, key, context)
     }
@@ -215,6 +270,7 @@ impl JsObject {
     ///  - [ECMAScript reference][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-ecmascript-function-objects-call-thisargument-argumentslist
+    #[track_caller]
     pub(crate) fn __call__(&self, argument_count: usize) -> CallValue {
         CallValue::Pending {
             func: self.vtable().__call__,
@@ -233,6 +289,7 @@ impl JsObject {
     ///  - [ECMAScript reference][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-ecmascript-function-objects-construct-argumentslist-newtarget
+    #[track_caller]
     pub(crate) fn __construct__(&self, argument_count: usize) -> CallValue {
         CallValue::Pending {
             func: self.vtable().__construct__,
@@ -283,19 +340,36 @@ pub(crate) struct InternalObjectMethods {
     pub(crate) __set_prototype_of__: fn(&JsObject, JsPrototype, &mut Context) -> JsResult<bool>,
     pub(crate) __is_extensible__: fn(&JsObject, &mut Context) -> JsResult<bool>,
     pub(crate) __prevent_extensions__: fn(&JsObject, &mut Context) -> JsResult<bool>,
-    pub(crate) __get_own_property__:
+    pub(crate) __get_own_property__: fn(
-        fn(&JsObject, &PropertyKey, &mut Context) -> JsResult<Option<PropertyDescriptor>>,
+        &JsObject,
-    pub(crate) __define_own_property__:
+        &PropertyKey,
-        fn(&JsObject, &PropertyKey, PropertyDescriptor, &mut Context) -> JsResult<bool>,
+        &mut InternalMethodContext<'_>,
-    pub(crate) __has_property__: fn(&JsObject, &PropertyKey, &mut Context) -> JsResult<bool>,
+    ) -> JsResult<Option<PropertyDescriptor>>,
-    pub(crate) __get__: fn(&JsObject, &PropertyKey, JsValue, &mut Context) -> JsResult<JsValue>,
+    pub(crate) __define_own_property__: fn(
-    pub(crate) __set__:
+        &JsObject,
-        fn(&JsObject, PropertyKey, JsValue, JsValue, &mut Context) -> JsResult<bool>,
+        &PropertyKey,
-    pub(crate) __delete__: fn(&JsObject, &PropertyKey, &mut Context) -> JsResult<bool>,
+        PropertyDescriptor,
-    pub(crate) __own_property_keys__: fn(&JsObject, &mut Context) -> JsResult<Vec<PropertyKey>>,
+        &mut InternalMethodContext<'_>,
-    pub(crate) __call__: fn(&JsObject, argument_count: usize, &mut Context) -> JsResult<CallValue>,
+    ) -> JsResult<bool>,
+    pub(crate) __has_property__:
+        fn(&JsObject, &PropertyKey, &mut InternalMethodContext<'_>) -> JsResult<bool>,
+    pub(crate) __get__:
+        fn(&JsObject, &PropertyKey, JsValue, &mut InternalMethodContext<'_>) -> JsResult<JsValue>,
+    pub(crate) __set__: fn(
+        &JsObject,
+        PropertyKey,
+        JsValue,
+        JsValue,
+        &mut InternalMethodContext<'_>,
+    ) -> JsResult<bool>,
+    pub(crate) __delete__:
+        fn(&JsObject, &PropertyKey, &mut InternalMethodContext<'_>) -> JsResult<bool>,
+    pub(crate) __own_property_keys__:
+        fn(&JsObject, context: &mut Context) -> JsResult<Vec<PropertyKey>>,
+    pub(crate) __call__:
+        fn(&JsObject, argument_count: usize, context: &mut Context) -> JsResult<CallValue>,
     pub(crate) __construct__:
-        fn(&JsObject, argument_count: usize, &mut Context) -> JsResult<CallValue>,
+        fn(&JsObject, argument_count: usize, context: &mut Context) -> JsResult<CallValue>,
 }
 
 /// The return value of an internal method (`[[Call]]` or `[[Construct]]`).
@@ -447,7 +521,7 @@ pub(crate) fn ordinary_prevent_extensions(
 pub(crate) fn ordinary_get_own_property(
     obj: &JsObject,
     key: &PropertyKey,
-    _context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<Option<PropertyDescriptor>> {
     let _timer = Profiler::global().start_event("Object::ordinary_get_own_property", "object");
     // 1. Assert: IsPropertyKey(P) is true.
@@ -464,7 +538,7 @@ pub(crate) fn ordinary_get_own_property(
     // 7. Set D.[[Enumerable]] to the value of X's [[Enumerable]] attribute.
     // 8. Set D.[[Configurable]] to the value of X's [[Configurable]] attribute.
     // 9. Return D.
-    Ok(obj.borrow().properties.get(key))
+    Ok(obj.borrow().properties.get_with_slot(key, context.slot()))
 }
 
 /// Abstract operation `OrdinaryDefineOwnProperty`.
@@ -477,9 +551,10 @@ pub(crate) fn ordinary_define_own_property(
     obj: &JsObject,
     key: &PropertyKey,
     desc: PropertyDescriptor,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     let _timer = Profiler::global().start_event("Object::ordinary_define_own_property", "object");
+
     // 1. Let current be ? O.[[GetOwnProperty]](P).
     let current = obj.__get_own_property__(key, context)?;
 
@@ -492,6 +567,7 @@ pub(crate) fn ordinary_define_own_property(
         extensible,
         desc,
         current,
+        context.slot(),
     ))
 }
 
@@ -504,18 +580,23 @@ pub(crate) fn ordinary_define_own_property(
 pub(crate) fn ordinary_has_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     let _timer = Profiler::global().start_event("Object::ordinary_has_property", "object");
     // 1. Assert: IsPropertyKey(P) is true.
     // 2. Let hasOwn be ? O.[[GetOwnProperty]](P).
     // 3. If hasOwn is not undefined, return true.
     if obj.__get_own_property__(key, context)?.is_some() {
+        context.slot().attributes |= SlotAttributes::FOUND;
+
         Ok(true)
     } else {
         // 4. Let parent be ? O.[[GetPrototypeOf]]().
         let parent = obj.__get_prototype_of__(context)?;
 
+        context.slot().set_not_cachable_if_already_prototype();
+        context.slot().attributes |= SlotAttributes::PROTOTYPE;
+
         parent
             // 5. If parent is not null, then
             // a. Return ? parent.[[HasProperty]](P).
@@ -534,7 +615,7 @@ pub(crate) fn ordinary_get(
     obj: &JsObject,
     key: &PropertyKey,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<JsValue> {
     let _timer = Profiler::global().start_event("Object::ordinary_get", "object");
     // 1. Assert: IsPropertyKey(P) is true.
@@ -544,6 +625,9 @@ pub(crate) fn ordinary_get(
         None => {
             // a. Let parent be ? O.[[GetPrototypeOf]]().
             if let Some(parent) = obj.__get_prototype_of__(context)? {
+                context.slot().set_not_cachable_if_already_prototype();
+                context.slot().attributes |= SlotAttributes::PROTOTYPE;
+
                 // c. Return ? parent.[[Get]](P, Receiver).
                 parent.__get__(key, receiver, context)
             }
@@ -552,20 +636,24 @@ pub(crate) fn ordinary_get(
                 Ok(JsValue::undefined())
             }
         }
-        Some(ref desc) => match desc.kind() {
+        Some(ref desc) => {
-            // 4. If IsDataDescriptor(desc) is true, return desc.[[Value]].
+            context.slot().attributes |= SlotAttributes::FOUND;
-            DescriptorKind::Data {
+
-                value: Some(value), ..
+            match desc.kind() {
-            } => Ok(value.clone()),
+                // 4. If IsDataDescriptor(desc) is true, return desc.[[Value]].
-            // 5. Assert: IsAccessorDescriptor(desc) is true.
+                DescriptorKind::Data {
-            // 6. Let getter be desc.[[Get]].
+                    value: Some(value), ..
-            DescriptorKind::Accessor { get: Some(get), .. } if !get.is_undefined() => {
+                } => Ok(value.clone()),
-                // 8. Return ? Call(getter, Receiver).
+                // 5. Assert: IsAccessorDescriptor(desc) is true.
-                get.call(&receiver, &[], context)
+                // 6. Let getter be desc.[[Get]].
+                DescriptorKind::Accessor { get: Some(get), .. } if !get.is_undefined() => {
+                    // 8. Return ? Call(getter, Receiver).
+                    get.call(&receiver, &[], context)
+                }
+                // 7. If getter is undefined, return undefined.
+                _ => Ok(JsValue::undefined()),
             }
-            // 7. If getter is undefined, return undefined.
+        }
-            _ => Ok(JsValue::undefined()),
-        },
     }
 }
 
@@ -580,7 +668,7 @@ pub(crate) fn ordinary_set(
     key: PropertyKey,
     value: JsValue,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     let _timer = Profiler::global().start_event("Object::ordinary_set", "object");
 
@@ -599,11 +687,20 @@ pub(crate) fn ordinary_set(
     // a. Let parent be ? O.[[GetPrototypeOf]]().
     // b. If parent is not null, then
     else if let Some(parent) = obj.__get_prototype_of__(context)? {
+        context.slot().set_not_cachable_if_already_prototype();
+        context.slot().attributes |= SlotAttributes::PROTOTYPE;
+
         // i. Return ? parent.[[Set]](P, V, Receiver).
         return parent.__set__(key, value, receiver, context);
     }
     // c. Else,
     else {
+        // It's not on prototype chain.
+        context
+            .slot()
+            .attributes
+            .remove(SlotAttributes::PROTOTYPE | SlotAttributes::NOT_CACHABLE);
+
         // i. Set ownDesc to the PropertyDescriptor { [[Value]]: undefined, [[Writable]]: true,
         // [[Enumerable]]: true, [[Configurable]]: true }.
         PropertyDescriptor::builder()
@@ -626,6 +723,12 @@ pub(crate) fn ordinary_set(
             return Ok(false);
         };
 
+        // NOTE(HaledOdat): If the object and receiver are not the same then it's not inline cachable for now.
+        context.slot().attributes.set(
+            SlotAttributes::NOT_CACHABLE,
+            !JsObject::equals(obj, receiver),
+        );
+
         // c. Let existingDescriptor be ? Receiver.[[GetOwnProperty]](P).
         // d. If existingDescriptor is not undefined, then
         if let Some(ref existing_desc) = receiver.__get_own_property__(&key, context)? {
@@ -647,12 +750,15 @@ pub(crate) fn ordinary_set(
                 context,
             );
         }
+
         // e. Else
         // i. Assert: Receiver does not currently have a property P.
         // ii. Return ? CreateDataProperty(Receiver, P, V).
-        return receiver.create_data_property(key, value, context);
+        return receiver.create_data_property_with_slot(key, value, context);
     }
 
+    context.slot().attributes |= SlotAttributes::FOUND;
+
     // 4. Assert: IsAccessorDescriptor(ownDesc) is true.
     debug_assert!(own_desc.is_accessor_descriptor());
 
@@ -679,7 +785,7 @@ pub(crate) fn ordinary_set(
 pub(crate) fn ordinary_delete(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     let _timer = Profiler::global().start_event("Object::ordinary_delete", "object");
     // 1. Assert: IsPropertyKey(P) is true.
@@ -752,7 +858,7 @@ pub(crate) fn is_compatible_property_descriptor(
         Profiler::global().start_event("Object::is_compatible_property_descriptor", "object");
 
     // 1. Return ValidateAndApplyPropertyDescriptor(undefined, undefined, Extensible, Desc, Current).
-    validate_and_apply_property_descriptor(None, extensible, desc, current)
+    validate_and_apply_property_descriptor(None, extensible, desc, current, &mut Slot::new())
 }
 
 /// Abstract operation `ValidateAndApplyPropertyDescriptor`
@@ -766,6 +872,7 @@ pub(crate) fn validate_and_apply_property_descriptor(
     extensible: bool,
     desc: PropertyDescriptor,
     current: Option<PropertyDescriptor>,
+    slot: &mut Slot,
 ) -> bool {
     let _timer =
         Profiler::global().start_event("Object::validate_and_apply_property_descriptor", "object");
@@ -781,7 +888,7 @@ pub(crate) fn validate_and_apply_property_descriptor(
         // b. Assert: extensible is true.
 
         if let Some((obj, key)) = obj_and_key {
-            obj.borrow_mut().properties.insert(
+            obj.borrow_mut().properties.insert_with_slot(
                 key,
                 // c. If IsGenericDescriptor(Desc) is true or IsDataDescriptor(Desc) is true, then
                 if desc.is_generic_descriptor() || desc.is_data_descriptor() {
@@ -803,7 +910,9 @@ pub(crate) fn validate_and_apply_property_descriptor(
                     // its default value.
                     desc.into_accessor_defaulted()
                 },
+                slot,
             );
+            slot.attributes |= SlotAttributes::FOUND;
         }
 
         // e. Return true.
@@ -899,7 +1008,10 @@ pub(crate) fn validate_and_apply_property_descriptor(
         // a. For each field of Desc that is present, set the corresponding attribute of the
         // property named P of object O to the value of the field.
         current.fill_with(&desc);
-        obj.borrow_mut().properties.insert(key, current);
+        obj.borrow_mut()
+            .properties
+            .insert_with_slot(key, current, slot);
+        slot.attributes |= SlotAttributes::FOUND;
     }
 
     // 10. Return true.

boa_engine/src/object/internal_methods/module_namespace.rs

@@ -11,7 +11,7 @@ use crate::{
 use super::{
     immutable_prototype, ordinary_define_own_property, ordinary_delete, ordinary_get,
     ordinary_get_own_property, ordinary_has_property, ordinary_own_property_keys,
-    InternalObjectMethods, ORDINARY_INTERNAL_METHODS,
+    InternalMethodContext, InternalObjectMethods, ORDINARY_INTERNAL_METHODS,
 };
 
 /// Definitions of the internal object methods for [**Module Namespace Exotic Objects**][spec].
@@ -84,7 +84,7 @@ fn module_namespace_exotic_prevent_extensions(_: &JsObject, _: &mut Context) ->
 fn module_namespace_exotic_get_own_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<Option<PropertyDescriptor>> {
     // 1. If P is a Symbol, return OrdinaryGetOwnProperty(O, P).
     let key = match key {
@@ -128,7 +128,7 @@ fn module_namespace_exotic_define_own_property(
     obj: &JsObject,
     key: &PropertyKey,
     desc: PropertyDescriptor,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. If P is a Symbol, return ! OrdinaryDefineOwnProperty(O, P, Desc).
     if let PropertyKey::Symbol(_) = key {
@@ -164,7 +164,7 @@ fn module_namespace_exotic_define_own_property(
 fn module_namespace_exotic_has_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. If P is a Symbol, return ! OrdinaryHasProperty(O, P).
     let key = match key {
@@ -193,7 +193,7 @@ fn module_namespace_exotic_get(
     obj: &JsObject,
     key: &PropertyKey,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<JsValue> {
     // 1. If P is a Symbol, then
     //     a. Return ! OrdinaryGet(O, P, Receiver).
@@ -273,7 +273,7 @@ fn module_namespace_exotic_set(
     _key: PropertyKey,
     _value: JsValue,
     _receiver: JsValue,
-    _context: &mut Context,
+    _context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. Return false.
     Ok(false)
@@ -285,7 +285,7 @@ fn module_namespace_exotic_set(
 fn module_namespace_exotic_delete(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. If P is a Symbol, then
     //     a. Return ! OrdinaryDelete(O, P).

boa_engine/src/object/internal_methods/proxy.rs

@@ -1,7 +1,7 @@
 use crate::{
     builtins::{array, object::Object},
     error::JsNativeError,
-    object::{InternalObjectMethods, JsObject, JsPrototype},
+    object::{shape::slot::SlotAttributes, InternalObjectMethods, JsObject, JsPrototype},
     property::{PropertyDescriptor, PropertyKey},
     string::utf16,
     value::Type,
@@ -9,7 +9,7 @@ use crate::{
 };
 use rustc_hash::FxHashSet;
 
-use super::{CallValue, ORDINARY_INTERNAL_METHODS};
+use super::{CallValue, InternalMethodContext, ORDINARY_INTERNAL_METHODS};
 
 /// Definitions of the internal object methods for array exotic objects.
 ///
@@ -268,8 +268,10 @@ pub(crate) fn proxy_exotic_prevent_extensions(
 pub(crate) fn proxy_exotic_get_own_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<Option<PropertyDescriptor>> {
+    context.slot().attributes |= SlotAttributes::NOT_CACHABLE;
+
     // 1. Let handler be O.[[ProxyHandler]].
     // 2. If handler is null, throw a TypeError exception.
     // 3. Assert: Type(handler) is Object.
@@ -284,6 +286,7 @@ pub(crate) fn proxy_exotic_get_own_property(
     let Some(trap) = handler.get_method(utf16!("getOwnPropertyDescriptor"), context)? else {
         // 6. If trap is undefined, then
         // a. Return ? target.[[GetOwnProperty]](P).
+
         return target.__get_own_property__(key, context);
     };
 
@@ -392,8 +395,10 @@ pub(crate) fn proxy_exotic_define_own_property(
     obj: &JsObject,
     key: &PropertyKey,
     desc: PropertyDescriptor,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
+    context.slot().attributes |= SlotAttributes::NOT_CACHABLE;
+
     // 1. Let handler be O.[[ProxyHandler]].
     // 2. If handler is null, throw a TypeError exception.
     // 3. Assert: Type(handler) is Object.
@@ -503,8 +508,10 @@ pub(crate) fn proxy_exotic_define_own_property(
 pub(crate) fn proxy_exotic_has_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
+    context.slot().attributes |= SlotAttributes::NOT_CACHABLE;
+
     // 1. Let handler be O.[[ProxyHandler]].
     // 2. If handler is null, throw a TypeError exception.
     // 3. Assert: Type(handler) is Object.
@@ -569,8 +576,11 @@ pub(crate) fn proxy_exotic_get(
     obj: &JsObject,
     key: &PropertyKey,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<JsValue> {
+    // Proxy object can't be cached.
+    context.slot().attributes |= SlotAttributes::NOT_CACHABLE;
+
     // 1. Let handler be O.[[ProxyHandler]].
     // 2. If handler is null, throw a TypeError exception.
     // 3. Assert: Type(handler) is Object.
@@ -638,8 +648,10 @@ pub(crate) fn proxy_exotic_set(
     key: PropertyKey,
     value: JsValue,
     receiver: JsValue,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
+    context.slot().attributes |= SlotAttributes::NOT_CACHABLE;
+
     // 1. Let handler be O.[[ProxyHandler]].
     // 2. If handler is null, throw a TypeError exception.
     // 3. Assert: Type(handler) is Object.
@@ -719,7 +731,7 @@ pub(crate) fn proxy_exotic_set(
 pub(crate) fn proxy_exotic_delete(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. Let handler be O.[[ProxyHandler]].
     // 2. If handler is null, throw a TypeError exception.
@@ -852,7 +864,7 @@ pub(crate) fn proxy_exotic_own_property_keys(
     // 16. For each element key of targetKeys, do
     for key in target_keys {
         // a. Let desc be ? target.[[GetOwnProperty]](key).
-        match target.__get_own_property__(&key, context)? {
+        match target.__get_own_property__(&key, &mut context.into())? {
             // b. If desc is not undefined and desc.[[Configurable]] is false, then
             Some(desc) if !desc.expect_configurable() => {
                 // i. Append key as an element of targetNonconfigurableKeys.

boa_engine/src/object/internal_methods/string.rs

@@ -5,7 +5,7 @@ use crate::{
     Context, JsResult,
 };
 
-use super::{InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
+use super::{InternalMethodContext, InternalObjectMethods, ORDINARY_INTERNAL_METHODS};
 
 /// Definitions of the internal object methods for string exotic objects.
 ///
@@ -29,7 +29,7 @@ pub(crate) static STRING_EXOTIC_INTERNAL_METHODS: InternalObjectMethods = Intern
 pub(crate) fn string_exotic_get_own_property(
     obj: &JsObject,
     key: &PropertyKey,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<Option<PropertyDescriptor>> {
     // 1. Assert: IsPropertyKey(P) is true.
     // 2. Let desc be OrdinaryGetOwnProperty(S, P).
@@ -54,7 +54,7 @@ pub(crate) fn string_exotic_define_own_property(
     obj: &JsObject,
     key: &PropertyKey,
     desc: PropertyDescriptor,
-    context: &mut Context,
+    context: &mut InternalMethodContext<'_>,
 ) -> JsResult<bool> {
     // 1. Assert: IsPropertyKey(P) is true.
     // 2. Let stringDesc be ! StringGetOwnProperty(S, P).

boa_engine/src/object/jsobject.rs

@@ -4,7 +4,7 @@
 
 use super::{
     internal_methods::{
-        non_existant_call, non_existant_construct, InternalObjectMethods,
+        non_existant_call, non_existant_construct, InternalMethodContext, InternalObjectMethods,
         ARRAY_EXOTIC_INTERNAL_METHODS,
     },
     shape::RootShape,
@@ -1000,6 +1000,8 @@ Cannot both specify accessors and a value or writable attribute",
     where
         K: Into<PropertyKey>,
     {
+        let context = &mut InternalMethodContext::new(context);
+
         // 1. Assert: Type(target) is Object.
         // 2. Assert: excludedItems is a List of property keys.
         // 3. If source is undefined or null, return target.

boa_engine/src/object/operations.rs

@@ -10,7 +10,7 @@ use crate::{
     Context, JsResult, JsSymbol, JsValue,
 };
 
-use super::ObjectKind;
+use super::{internal_methods::InternalMethodContext, ObjectKind};
 
 /// Object integrity level.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -73,7 +73,11 @@ impl JsObject {
         // 1. Assert: Type(O) is Object.
         // 2. Assert: IsPropertyKey(P) is true.
         // 3. Return ? O.[[Get]](P, O).
-        self.__get__(&key.into(), self.clone().into(), context)
+        self.__get__(
+            &key.into(),
+            self.clone().into(),
+            &mut InternalMethodContext::new(context),
+        )
     }
 
     /// set property of object or throw if bool flag is passed.
@@ -92,7 +96,12 @@ impl JsObject {
         // 2. Assert: IsPropertyKey(P) is true.
         // 3. Assert: Type(Throw) is Boolean.
         // 4. Let success be ? O.[[Set]](P, V, O).
-        let success = self.__set__(key.clone(), value.into(), self.clone().into(), context)?;
+        let success = self.__set__(
+            key.clone(),
+            value.into(),
+            self.clone().into(),
+            &mut InternalMethodContext::new(context),
+        )?;
         // 5. If success is false and Throw is true, throw a TypeError exception.
         if !success && throw {
             return Err(JsNativeError::typ()
@@ -115,6 +124,38 @@ impl JsObject {
         value: V,
         context: &mut Context,
     ) -> JsResult<bool>
+    where
+        K: Into<PropertyKey>,
+        V: Into<JsValue>,
+    {
+        // 1. Assert: Type(O) is Object.
+        // 2. Assert: IsPropertyKey(P) is true.
+        // 3. Let newDesc be the PropertyDescriptor { [[Value]]: V, [[Writable]]: true, [[Enumerable]]: true, [[Configurable]]: true }.
+        let new_desc = PropertyDescriptor::builder()
+            .value(value)
+            .writable(true)
+            .enumerable(true)
+            .configurable(true);
+        // 4. Return ? O.[[DefineOwnProperty]](P, newDesc).
+        self.__define_own_property__(
+            &key.into(),
+            new_desc.into(),
+            &mut InternalMethodContext::new(context),
+        )
+    }
+
+    /// Create data property
+    ///
+    /// More information:
+    ///  - [ECMAScript reference][spec]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-createdataproperty
+    pub(crate) fn create_data_property_with_slot<K, V>(
+        &self,
+        key: K,
+        value: V,
+        context: &mut InternalMethodContext<'_>,
+    ) -> JsResult<bool>
     where
         K: Into<PropertyKey>,
         V: Into<JsValue>,
@@ -221,7 +262,11 @@ impl JsObject {
         // 1. Assert: Type(O) is Object.
         // 2. Assert: IsPropertyKey(P) is true.
         // 3. Let success be ? O.[[DefineOwnProperty]](P, desc).
-        let success = self.__define_own_property__(&key, desc.into(), context)?;
+        let success = self.__define_own_property__(
+            &key,
+            desc.into(),
+            &mut InternalMethodContext::new(context),
+        )?;
         // 4. If success is false, throw a TypeError exception.
         if !success {
             return Err(JsNativeError::typ()
@@ -246,7 +291,7 @@ impl JsObject {
         // 1. Assert: Type(O) is Object.
         // 2. Assert: IsPropertyKey(P) is true.
         // 3. Let success be ? O.[[Delete]](P).
-        let success = self.__delete__(&key, context)?;
+        let success = self.__delete__(&key, &mut InternalMethodContext::new(context))?;
         // 4. If success is false, throw a TypeError exception.
         if !success {
             return Err(JsNativeError::typ()
@@ -270,7 +315,8 @@ impl JsObject {
         // 1. Assert: Type(O) is Object.
         // 2. Assert: IsPropertyKey(P) is true.
         // 3. Return ? O.[[HasProperty]](P).
-        self.__has_property__(&key.into(), context)
+
+        self.__has_property__(&key.into(), &mut InternalMethodContext::new(context))
     }
 
     /// Check if object has an own property.
@@ -287,7 +333,7 @@ impl JsObject {
         // 1. Assert: Type(O) is Object.
         // 2. Assert: IsPropertyKey(P) is true.
         // 3. Let desc be ? O.[[GetOwnProperty]](P).
-        let desc = self.__get_own_property__(&key, context)?;
+        let desc = self.__get_own_property__(&key, &mut InternalMethodContext::new(context))?;
         // 4. If desc is undefined, return false.
         // 5. Return true.
         Ok(desc.is_some())
@@ -403,14 +449,14 @@ impl JsObject {
         // 2. Assert: level is either sealed or frozen.
 
         // 3. Let status be ? O.[[PreventExtensions]]().
-        let status = self.__prevent_extensions__(context)?;
+        let status = self.__prevent_extensions__(&mut InternalMethodContext::new(context))?;
         // 4. If status is false, return false.
         if !status {
             return Ok(false);
         }
 
         // 5. Let keys be ? O.[[OwnPropertyKeys]]().
-        let keys = self.__own_property_keys__(context)?;
+        let keys = self.__own_property_keys__(&mut InternalMethodContext::new(context))?;
 
         match level {
             // 6. If level is sealed, then
@@ -431,7 +477,8 @@ impl JsObject {
                 // b. For each element k of keys, do
                 for k in keys {
                     // i. Let currentDesc be ? O.[[GetOwnProperty]](k).
-                    let current_desc = self.__get_own_property__(&k, context)?;
+                    let current_desc =
+                        self.__get_own_property__(&k, &mut InternalMethodContext::new(context))?;
                     // ii. If currentDesc is not undefined, then
                     if let Some(current_desc) = current_desc {
                         // 1. If IsAccessorDescriptor(currentDesc) is true, then
@@ -481,12 +528,13 @@ impl JsObject {
 
         // 5. NOTE: If the object is extensible, none of its properties are examined.
         // 6. Let keys be ? O.[[OwnPropertyKeys]]().
-        let keys = self.__own_property_keys__(context)?;
+        let keys = self.__own_property_keys__(&mut InternalMethodContext::new(context))?;
 
         // 7. For each element k of keys, do
         for k in keys {
             // a. Let currentDesc be ? O.[[GetOwnProperty]](k).
-            let current_desc = self.__get_own_property__(&k, context)?;
+            let current_desc =
+                self.__get_own_property__(&k, &mut InternalMethodContext::new(context))?;
             // b. If currentDesc is not undefined, then
             if let Some(current_desc) = current_desc {
                 // i. If currentDesc.[[Configurable]] is true, return false.
@@ -595,7 +643,7 @@ impl JsObject {
     ) -> JsResult<Vec<JsValue>> {
         // 1. Assert: Type(O) is Object.
         // 2. Let ownKeys be ? O.[[OwnPropertyKeys]]().
-        let own_keys = self.__own_property_keys__(context)?;
+        let own_keys = self.__own_property_keys__(&mut InternalMethodContext::new(context))?;
         // 3. Let properties be a new empty List.
         let mut properties = vec![];
 
@@ -610,7 +658,8 @@ impl JsObject {
 
             if let Some(key_str) = key_str {
                 // i. Let desc be ? O.[[GetOwnProperty]](key).
-                let desc = self.__get_own_property__(&key, context)?;
+                let desc =
+                    self.__get_own_property__(&key, &mut InternalMethodContext::new(context))?;
                 // ii. If desc is not undefined and desc.[[Enumerable]] is true, then
                 if let Some(desc) = desc {
                     if desc.expect_enumerable() {
@@ -661,7 +710,12 @@ impl JsObject {
 
         // 1. Assert: IsPropertyKey(P) is true.
         // 2. Let func be ? GetV(V, P).
-        match &self.__get__(&key.into(), self.clone().into(), context)? {
+
+        match &self.__get__(
+            &key.into(),
+            self.clone().into(),
+            &mut InternalMethodContext::new(context),
+        )? {
             // 3. If func is either undefined or null, return undefined.
             JsValue::Undefined | JsValue::Null => Ok(None),
             // 5. Return func.
@@ -1066,7 +1120,11 @@ impl JsObject {
 
         // 1. If argumentsList is not present, set argumentsList to a new empty List.
         // 2. Let func be ? GetV(V, P).
-        let func = self.__get__(&key.into(), this_value.clone(), context)?;
+        let func = self.__get__(
+            &key.into(),
+            this_value.clone(),
+            &mut InternalMethodContext::new(context),
+        )?;
 
         // 3. Return ? Call(func, V, argumentsList)
         func.call(&this_value, args, context)
@@ -1092,7 +1150,12 @@ impl JsValue {
         let o = self.to_object(context)?;
 
         // 2. Return ? O.[[Get]](P, V).
-        o.__get__(&key.into(), self.clone(), context)
+
+        o.__get__(
+            &key.into(),
+            self.clone(),
+            &mut InternalMethodContext::new(context),
+        )
     }
 
     /// Abstract operation `GetMethod ( V, P )`
@@ -1260,7 +1323,7 @@ impl JsValue {
         // 6. Repeat,
         loop {
             // a. Set O to ? O.[[GetPrototypeOf]]().
-            object = match object.__get_prototype_of__(context)? {
+            object = match object.__get_prototype_of__(&mut InternalMethodContext::new(context))? {
                 Some(obj) => obj,
                 // b. If O is null, return false.
                 None => return Ok(false),

boa_engine/src/object/property_map.rs

@@ -277,6 +277,28 @@ impl PropertyMap {
         None
     }
 
+    /// Get the property with the given key from the [`PropertyMap`].
+    #[must_use]
+    pub(crate) fn get_with_slot(
+        &self,
+        key: &PropertyKey,
+        out_slot: &mut Slot,
+    ) -> Option<PropertyDescriptor> {
+        if let PropertyKey::Index(index) = key {
+            return self.indexed_properties.get(index.get());
+        }
+        if let Some(slot) = self.shape.lookup(key) {
+            out_slot.index = slot.index;
+
+            // Remove all descriptor attributes, but keep inline caching bits.
+            out_slot.attributes =
+                (out_slot.attributes & SlotAttributes::INLINE_CACHE_BITS) | slot.attributes;
+            return Some(self.get_storage(slot));
+        }
+
+        None
+    }
+
     /// Get the property with the given key from the [`PropertyMap`].
     #[must_use]
     pub(crate) fn get_storage(&self, Slot { index, attributes }: Slot) -> PropertyDescriptor {
@@ -300,6 +322,17 @@ impl PropertyMap {
 
     /// Insert the given property descriptor with the given key [`PropertyMap`].
     pub fn insert(&mut self, key: &PropertyKey, property: PropertyDescriptor) -> bool {
+        let mut dummy_slot = Slot::new();
+        self.insert_with_slot(key, property, &mut dummy_slot)
+    }
+
+    /// Insert the given property descriptor with the given key [`PropertyMap`].
+    pub(crate) fn insert_with_slot(
+        &mut self,
+        key: &PropertyKey,
+        property: PropertyDescriptor,
+        out_slot: &mut Slot,
+    ) -> bool {
         if let PropertyKey::Index(index) = key {
             return self.indexed_properties.insert(index.get(), property);
         }
@@ -346,6 +379,9 @@ impl PropertyMap {
             } else {
                 self.storage[index] = property.expect_value().clone();
             }
+            out_slot.index = slot.index;
+            out_slot.attributes =
+                (out_slot.attributes & SlotAttributes::INLINE_CACHE_BITS) | attributes;
             return true;
         }
 
@@ -364,6 +400,10 @@ impl PropertyMap {
             })
         );
 
+        out_slot.index = self.storage.len() as u32;
+        out_slot.attributes =
+            (out_slot.attributes & SlotAttributes::INLINE_CACHE_BITS) | attributes;
+
         if attributes.is_accessor_descriptor() {
             self.storage.push(
                 property

boa_engine/src/object/shape/mod.rs

@@ -16,7 +16,11 @@ use boa_gc::{Finalize, Trace};
 
 use crate::property::PropertyKey;
 
-use self::{shared_shape::TransitionKey, slot::Slot};
+use self::{
+    shared_shape::{TransitionKey, WeakSharedShape},
+    slot::Slot,
+    unique_shape::WeakUniqueShape,
+};
 
 use super::JsPrototype;
 
@@ -225,3 +229,35 @@ impl From<SharedShape> for Shape {
         }
     }
 }
+
+/// Represents a weak reaference to an object's [`Shape`].
+#[derive(Debug, Trace, Finalize, Clone)]
+pub(crate) enum WeakShape {
+    Unique(WeakUniqueShape),
+    Shared(WeakSharedShape),
+    None,
+}
+
+impl WeakShape {
+    /// Return location in memory of the [`Shape`].
+    ///
+    /// Returns `0` if the shape has been freed.
+    #[inline]
+    #[must_use]
+    pub(crate) fn to_addr_usize(&self) -> usize {
+        match self {
+            WeakShape::Shared(shape) => shape.to_addr_usize(),
+            WeakShape::Unique(shape) => shape.to_addr_usize(),
+            WeakShape::None => 0,
+        }
+    }
+}
+
+impl From<&Shape> for WeakShape {
+    fn from(value: &Shape) -> Self {
+        match &value.inner {
+            Inner::Shared(shape) => WeakShape::Shared(shape.into()),
+            Inner::Unique(shape) => WeakShape::Unique(shape.into()),
+        }
+    }
+}

boa_engine/src/object/shape/shared_shape/mod.rs

@@ -7,7 +7,7 @@ mod tests;
 use std::{collections::hash_map::RandomState, hash::Hash};
 
 use bitflags::bitflags;
-use boa_gc::{empty_trace, Finalize, Gc, Trace};
+use boa_gc::{empty_trace, Finalize, Gc, Trace, WeakGc};
 use indexmap::IndexMap;
 
 use crate::{object::JsPrototype, property::PropertyKey, JsObject};
@@ -474,9 +474,37 @@ impl SharedShape {
         )
     }
 
-    /// Return location in memory of the [`UniqueShape`].
+    /// Return location in memory of the [`SharedShape`].
     pub(crate) fn to_addr_usize(&self) -> usize {
         let ptr: *const _ = self.inner.as_ref();
         ptr as usize
     }
 }
+
+/// Represents a weak reference to [`SharedShape`].
+#[derive(Debug, Trace, Finalize, Clone)]
+pub(crate) struct WeakSharedShape {
+    inner: WeakGc<Inner>,
+}
+
+impl WeakSharedShape {
+    /// Return location in memory of the [`WeakSharedShape`].
+    ///
+    /// Returns `0` if the inner [`SharedShape`] has been freed.
+    #[inline]
+    #[must_use]
+    pub(crate) fn to_addr_usize(&self) -> usize {
+        self.inner.upgrade().map_or(0, |inner| {
+            let ptr: *const _ = inner.as_ref();
+            ptr as usize
+        })
+    }
+}
+
+impl From<&SharedShape> for WeakSharedShape {
+    fn from(value: &SharedShape) -> Self {
+        WeakSharedShape {
+            inner: WeakGc::new(&value.inner),
+        }
+    }
+}

boa_engine/src/object/shape/slot.rs

@@ -10,6 +10,11 @@ bitflags! {
         const CONFIGURABLE = 0b0000_0100;
         const GET = 0b0000_1000;
         const SET = 0b0001_0000;
+
+        const INLINE_CACHE_BITS = 0b1110_0000;
+        const PROTOTYPE    = 0b0010_0000;
+        const FOUND        = 0b0100_0000;
+        const NOT_CACHABLE = 0b1000_0000;
     }
 }
 
@@ -36,6 +41,10 @@ impl SlotAttributes {
         // accessor take 2 positions in the storage to accomodate for the `get` and `set` fields.
         1 + u32::from(self.is_accessor_descriptor())
     }
+
+    pub(crate) const fn is_cachable(self) -> bool {
+        !self.contains(Self::NOT_CACHABLE) && self.contains(Self::FOUND)
+    }
 }
 
 /// Represents an [`u32`] index and it's slot attributes of an element in a object storage.
@@ -49,6 +58,17 @@ pub(crate) struct Slot {
 }
 
 impl Slot {
+    pub(crate) const fn new() -> Self {
+        Self {
+            index: 0,
+            attributes: SlotAttributes::empty(),
+        }
+    }
+
+    pub(crate) const fn is_cachable(self) -> bool {
+        self.attributes.is_cachable()
+    }
+
     /// Get the width of the slot.
     pub(crate) fn width(self) -> u32 {
         self.attributes.width()
@@ -74,4 +94,17 @@ impl Slot {
             attributes: new_attributes,
         }
     }
+
+    pub(crate) fn set_not_cachable_if_already_prototype(&mut self) {
+        // NOTE(HalidOdat): This is a bit hack to avoid conditional branches.
+        //
+        // Equivalent to:
+        // if slot.attributes.contains(SlotAttributes::PROTOTYPE) {
+        //     slot.attributes |= SlotAttributes::NOT_CACHABLE;
+        // }
+        //
+        self.attributes |= SlotAttributes::from_bits_retain(
+            (self.attributes.bits() & SlotAttributes::PROTOTYPE.bits()) << 2,
+        );
+    }
 }

boa_engine/src/object/shape/unique_shape.rs

@@ -1,6 +1,6 @@
 use std::{cell::RefCell, fmt::Debug};
 
-use boa_gc::{Finalize, Gc, GcRefCell, Trace};
+use boa_gc::{Finalize, Gc, GcRefCell, Trace, WeakGc};
 
 use crate::property::PropertyKey;
 
@@ -239,3 +239,31 @@ impl UniqueShape {
         ptr as usize
     }
 }
+
+/// Represents a weak reference to [`UniqueShape`].
+#[derive(Debug, Clone, Trace, Finalize)]
+pub(crate) struct WeakUniqueShape {
+    inner: WeakGc<Inner>,
+}
+
+impl WeakUniqueShape {
+    /// Return location in memory of the [`WeakUniqueShape`].
+    ///
+    /// Returns `0` if the inner [`UniqueShape`] has been freed.
+    #[inline]
+    #[must_use]
+    pub(crate) fn to_addr_usize(&self) -> usize {
+        self.inner.upgrade().map_or(0, |inner| {
+            let ptr: *const _ = inner.as_ref();
+            ptr as usize
+        })
+    }
+}
+
+impl From<&UniqueShape> for WeakUniqueShape {
+    fn from(value: &UniqueShape) -> Self {
+        WeakUniqueShape {
+            inner: WeakGc::new(&value.inner),
+        }
+    }
+}

boa_engine/src/value/tests.rs

@@ -2,6 +2,7 @@ use boa_macros::utf16;
 use indoc::indoc;
 
 use super::*;
+use crate::object::internal_methods::InternalMethodContext;
 use crate::{js_string, run_test_actions, TestAction};
 
 use std::collections::hash_map::DefaultHasher;
@@ -197,10 +198,13 @@ fn float_display() {
 
 #[test]
 fn string_length_is_not_enumerable() {
-    run_test_actions([TestAction::assert_context(|ctx| {
+    run_test_actions([TestAction::assert_context(|context| {
-        let object = JsValue::new(js_string!("foo")).to_object(ctx).unwrap();
+        let object = JsValue::new(js_string!("foo")).to_object(context).unwrap();
         let length_desc = object
-            .__get_own_property__(&js_string!("length").into(), ctx)
+            .__get_own_property__(
+                &PropertyKey::from(js_string!("length")),
+                &mut InternalMethodContext::new(context),
+            )
             .unwrap()
             .unwrap();
         !length_desc.expect_enumerable()
@@ -209,16 +213,20 @@ fn string_length_is_not_enumerable() {
 
 #[test]
 fn string_length_is_in_utf16_codeunits() {
-    run_test_actions([TestAction::assert_context(|ctx| {
+    run_test_actions([TestAction::assert_context(|context| {
         // 😀 is one Unicode code point, but 2 UTF-16 code units
-        let object = JsValue::new(js_string!("😀")).to_object(ctx).unwrap();
+        let object = JsValue::new(js_string!("😀")).to_object(context).unwrap();
+
         let length_desc = object
-            .__get_own_property__(&js_string!("length").into(), ctx)
+            .__get_own_property__(
+                &PropertyKey::from(js_string!("length")),
+                &mut InternalMethodContext::new(context),
+            )
             .unwrap()
             .unwrap();
         length_desc
             .expect_value()
-            .to_integer_or_infinity(ctx)
+            .to_integer_or_infinity(context)
             .unwrap()
             == IntegerOrInfinity::Integer(2)
     })]);

boa_engine/src/vm/code_block.rs

@@ -5,12 +5,15 @@
 use crate::{
     builtins::function::{OrdinaryFunction, ThisMode},
     environments::{BindingLocator, CompileTimeEnvironment},
-    object::{JsObject, ObjectData},
+    object::{
+        shape::{slot::Slot, Shape, WeakShape},
+        JsObject, ObjectData,
+    },
     Context, JsBigInt, JsString, JsValue,
 };
 use bitflags::bitflags;
 use boa_ast::function::FormalParameterList;
-use boa_gc::{empty_trace, Finalize, Gc, Trace};
+use boa_gc::{empty_trace, Finalize, Gc, GcRefCell, Trace};
 use boa_profiler::Profiler;
 use std::{cell::Cell, fmt::Display, mem::size_of, rc::Rc};
 use thin_vec::ThinVec;
@@ -117,6 +120,43 @@ pub(crate) enum Constant {
     CompileTimeEnvironment(#[unsafe_ignore_trace] Rc<CompileTimeEnvironment>),
 }
 
+/// An inline cache entry for a property access.
+#[derive(Clone, Debug, Trace, Finalize)]
+pub(crate) struct InlineCache {
+    /// The property that is accessed.
+    pub(crate) name: JsString,
+
+    /// A pointer is kept to the shape to avoid the shape from being deallocated.
+    pub(crate) shape: GcRefCell<WeakShape>,
+
+    /// The [`Slot`] of the property.
+    #[unsafe_ignore_trace]
+    pub(crate) slot: Cell<Slot>,
+}
+
+impl InlineCache {
+    pub(crate) const fn new(name: JsString) -> Self {
+        Self {
+            name,
+            shape: GcRefCell::new(WeakShape::None),
+            slot: Cell::new(Slot::new()),
+        }
+    }
+
+    pub(crate) fn set(&self, shape: &Shape, slot: Slot) {
+        *self.shape.borrow_mut() = shape.into();
+        self.slot.set(slot);
+    }
+
+    pub(crate) fn slot(&self) -> Slot {
+        self.slot.get()
+    }
+
+    pub(crate) fn matches(&self, shape: &Shape) -> bool {
+        self.shape.borrow().to_addr_usize() == shape.to_addr_usize()
+    }
+}
+
 /// The internal representation of a JavaScript function.
 ///
 /// A `CodeBlock` is generated for each function compiled by the
@@ -142,6 +182,7 @@ pub struct CodeBlock {
     pub(crate) params: FormalParameterList,
 
     /// Bytecode
+    #[unsafe_ignore_trace]
     pub(crate) bytecode: Box<[u8]>,
 
     pub(crate) constants: ThinVec<Constant>,
@@ -153,6 +194,9 @@ pub struct CodeBlock {
     /// Exception [`Handler`]s.
     #[unsafe_ignore_trace]
     pub(crate) handlers: ThinVec<Handler>,
+
+    /// inline caching
+    pub(crate) ic: Box<[InlineCache]>,
 }
 
 /// ---- `CodeBlock` public API ----
@@ -172,6 +216,7 @@ impl CodeBlock {
             this_mode: ThisMode::Global,
             params: FormalParameterList::default(),
             handlers: ThinVec::default(),
+            ic: Box::default(),
         }
     }
 
@@ -450,9 +495,7 @@ impl CodeBlock {
                         .to_std_string_escaped()
                 )
             }
-            Instruction::GetPropertyByName { index }
+            Instruction::DefineOwnPropertyByName { index }
-            | Instruction::SetPropertyByName { index }
-            | Instruction::DefineOwnPropertyByName { index }
             | Instruction::DefineClassStaticMethodByName { index }
             | Instruction::DefineClassMethodByName { index }
             | Instruction::SetPropertyGetterByName { index }
@@ -481,6 +524,18 @@ impl CodeBlock {
                         .to_std_string_escaped(),
                 )
             }
+            Instruction::GetPropertyByName { index } | Instruction::SetPropertyByName { index } => {
+                let ic = &self.ic[index.value() as usize];
+                let slot = ic.slot();
+                format!(
+                    "{:04}: '{}', Shape: 0x{:x}, Slot: index: {}, attributes {:?}",
+                    index.value(),
+                    ic.name.to_std_string_escaped(),
+                    ic.shape.borrow().to_addr_usize(),
+                    slot.index,
+                    slot.attributes,
+                )
+            }
             Instruction::PushPrivateEnvironment { name_indices } => {
                 format!("{name_indices:?}")
             }

boa_engine/src/vm/mod.rs

@@ -39,6 +39,7 @@ pub(crate) use {
     call_frame::CallFrameFlags,
     code_block::{
         create_function_object, create_function_object_fast, CodeBlockFlags, Constant, Handler,
+        InlineCache,
     },
     completion_record::CompletionRecord,
     opcode::BindingOpcode,

boa_engine/src/vm/opcode/define/class/getter.rs

@@ -1,5 +1,6 @@
 use crate::{
     builtins::function::set_function_name,
+    object::internal_methods::InternalMethodContext,
     property::PropertyDescriptor,
     vm::{opcode::Operation, CompletionType},
     Context, JsResult, JsString,
@@ -35,7 +36,7 @@ impl DefineClassStaticGetterByName {
             function_mut.set_home_object(class.clone());
         }
         let set = class
-            .__get_own_property__(&key, context)?
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::set)
             .cloned();
@@ -47,7 +48,7 @@ impl DefineClassStaticGetterByName {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -104,7 +105,7 @@ impl DefineClassGetterByName {
             function_mut.set_home_object(class_proto.clone());
         }
         let set = class_proto
-            .__get_own_property__(&key, context)?
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::set)
             .cloned();
@@ -116,7 +117,7 @@ impl DefineClassGetterByName {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -174,8 +175,9 @@ impl Operation for DefineClassStaticGetterByValue {
                 .expect("method must be function object");
             function_mut.set_home_object(class.clone());
         }
+
         let set = class
-            .__get_own_property__(&key, context)?
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::set)
             .cloned();
@@ -225,7 +227,7 @@ impl Operation for DefineClassGetterByValue {
             function_mut.set_home_object(class_proto.clone());
         }
         let set = class_proto
-            .__get_own_property__(&key, context)?
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::set)
             .cloned();
@@ -237,7 +239,7 @@ impl Operation for DefineClassGetterByValue {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }

boa_engine/src/vm/opcode/define/class/method.rs

@@ -1,5 +1,6 @@
 use crate::{
     builtins::function::set_function_name,
+    object::internal_methods::InternalMethodContext,
     property::PropertyDescriptor,
     vm::{opcode::Operation, CompletionType},
     Context, JsResult,
@@ -43,7 +44,7 @@ impl DefineClassStaticMethodByName {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -108,7 +109,7 @@ impl DefineClassMethodByName {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -221,7 +222,7 @@ impl Operation for DefineClassMethodByValue {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }

boa_engine/src/vm/opcode/define/class/setter.rs

@@ -1,5 +1,6 @@
 use crate::{
     builtins::function::set_function_name,
+    object::internal_methods::InternalMethodContext,
     property::PropertyDescriptor,
     vm::{opcode::Operation, CompletionType},
     Context, JsResult, JsString,
@@ -35,7 +36,7 @@ impl DefineClassStaticSetterByName {
             function_mut.set_home_object(class.clone());
         }
         let get = class
-            .__get_own_property__(&key, context)?
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::get)
             .cloned();
@@ -48,7 +49,7 @@ impl DefineClassStaticSetterByName {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -105,7 +106,7 @@ impl DefineClassSetterByName {
             function_mut.set_home_object(class_proto.clone());
         }
         let get = class_proto
-            .__get_own_property__(&key, context)?
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::get)
             .cloned();
@@ -118,7 +119,7 @@ impl DefineClassSetterByName {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
 
         Ok(CompletionType::Normal)
@@ -178,7 +179,7 @@ impl Operation for DefineClassStaticSetterByValue {
             function_mut.set_home_object(class.clone());
         }
         let get = class
-            .__get_own_property__(&key, context)?
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::get)
             .cloned();
@@ -230,7 +231,7 @@ impl Operation for DefineClassSetterByValue {
             function_mut.set_home_object(class_proto.clone());
         }
         let get = class_proto
-            .__get_own_property__(&key, context)?
+            .__get_own_property__(&key, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::get)
             .cloned();
@@ -243,7 +244,7 @@ impl Operation for DefineClassSetterByValue {
                 .enumerable(false)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
 
         Ok(CompletionType::Normal)

boa_engine/src/vm/opcode/define/own_property.rs

@@ -1,4 +1,5 @@
 use crate::{
+    object::internal_methods::InternalMethodContext,
     property::PropertyDescriptor,
     vm::{opcode::Operation, CompletionType},
     Context, JsNativeError, JsResult,
@@ -29,7 +30,7 @@ impl DefineOwnPropertyByName {
                 .enumerable(true)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -86,7 +87,7 @@ impl Operation for DefineOwnPropertyByValue {
                 .enumerable(true)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         if !success {
             return Err(JsNativeError::typ()

boa_engine/src/vm/opcode/delete/mod.rs

@@ -1,5 +1,6 @@
 use crate::{
     error::JsNativeError,
+    object::internal_methods::InternalMethodContext,
     vm::{opcode::Operation, CompletionType},
     Context, JsResult,
 };
@@ -21,8 +22,9 @@ impl DeletePropertyByName {
             .code_block()
             .constant_string(index)
             .into();
-        let result = object.__delete__(&key, context)?;
+
-        if !result && context.vm.frame().code_block.strict() {
+        let result = object.__delete__(&key, &mut InternalMethodContext::new(context))?;
+        if !result && context.vm.frame().code_block().strict() {
             return Err(JsNativeError::typ()
                 .with_message("Cannot delete property")
                 .into());
@@ -70,8 +72,9 @@ impl Operation for DeletePropertyByValue {
         let value = context.vm.pop();
         let object = value.to_object(context)?;
         let property_key = key_value.to_property_key(context)?;
-        let result = object.__delete__(&property_key, context)?;
+
-        if !result && context.vm.frame().code_block.strict() {
+        let result = object.__delete__(&property_key, &mut InternalMethodContext::new(context))?;
+        if !result && context.vm.frame().code_block().strict() {
             return Err(JsNativeError::typ()
                 .with_message("Cannot delete property")
                 .into());

boa_engine/src/vm/opcode/environment/mod.rs

@@ -1,5 +1,6 @@
 use crate::{
     error::JsNativeError,
+    object::internal_methods::InternalMethodContext,
     vm::{opcode::Operation, CompletionType},
     Context, JsResult, JsValue,
 };
@@ -54,7 +55,7 @@ impl Operation for Super {
         };
 
         let value = home_object
-            .map(|o| o.__get_prototype_of__(context))
+            .map(|o| o.__get_prototype_of__(&mut InternalMethodContext::new(context)))
             .transpose()?
             .flatten()
             .map_or_else(JsValue::null, JsValue::from);
@@ -85,7 +86,7 @@ impl Operation for SuperCallPrepare {
             .expect("super call must be in function environment");
         let active_function = this_env.slots().function_object().clone();
         let super_constructor = active_function
-            .__get_prototype_of__(context)
+            .__get_prototype_of__(&mut InternalMethodContext::new(context))
             .expect("function object must have prototype");
 
         context
@@ -242,7 +243,7 @@ impl Operation for SuperCallDerived {
             .clone();
         let active_function = this_env.slots().function_object().clone();
         let super_constructor = active_function
-            .__get_prototype_of__(context)
+            .__get_prototype_of__(&mut InternalMethodContext::new(context))
             .expect("function object must have prototype")
             .expect("function object must have prototype");
 

boa_engine/src/vm/opcode/get/property.rs

@@ -1,4 +1,5 @@
 use crate::{
+    object::{internal_methods::InternalMethodContext, shape::slot::SlotAttributes},
     property::PropertyKey,
     vm::{opcode::Operation, CompletionType},
     Context, JsResult,
@@ -21,14 +22,52 @@ impl GetPropertyByName {
             value.to_object(context)?
         };
 
-        let key = context
+        let ic = &context.vm.frame().code_block().ic[index];
-            .vm
+        let mut slot = ic.slot();
-            .frame()
+        if slot.is_cachable() {
-            .code_block()
+            let object_borrowed = object.borrow();
-            .constant_string(index)
+            if ic.matches(object_borrowed.shape()) {
-            .into();
+                let mut result = if slot.attributes.contains(SlotAttributes::PROTOTYPE) {
+                    let prototype = object
+                        .borrow()
+                        .properties()
+                        .shape
+                        .prototype()
+                        .expect("prototype should have value");
+                    let prototype = prototype.borrow();
+                    prototype.properties().storage[slot.index as usize].clone()
+                } else {
+                    object_borrowed.properties().storage[slot.index as usize].clone()
+                };
+
+                drop(object_borrowed);
+                if slot.attributes.has_get() && result.is_object() {
+                    result = result.as_object().expect("should contain getter").call(
+                        &receiver,
+                        &[],
+                        context,
+                    )?;
+                }
+                context.vm.push(result);
+                return Ok(CompletionType::Normal);
+            }
+        }
+
+        let key: PropertyKey = ic.name.clone().into();
+
+        let context = &mut InternalMethodContext::new(context);
         let result = object.__get__(&key, receiver, context)?;
 
+        slot = *context.slot();
+
+        // Cache the property.
+        if slot.attributes.is_cachable() {
+            let ic = &context.vm.frame().code_block.ic[index];
+            let object_borrowed = object.borrow();
+            let shape = object_borrowed.shape();
+            ic.set(shape, slot);
+        }
+
         context.vm.push(result);
         Ok(CompletionType::Normal)
     }
@@ -95,7 +134,7 @@ impl Operation for GetPropertyByValue {
         }
 
         // Slow path:
-        let result = object.__get__(&key, receiver, context)?;
+        let result = object.__get__(&key, receiver, &mut InternalMethodContext::new(context))?;
 
         context.vm.push(result);
         Ok(CompletionType::Normal)
@@ -143,7 +182,7 @@ impl Operation for GetPropertyByValuePush {
         }
 
         // Slow path:
-        let result = object.__get__(&key, receiver, context)?;
+        let result = object.__get__(&key, receiver, &mut InternalMethodContext::new(context))?;
 
         context.vm.push(key);
         context.vm.push(result);

boa_engine/src/vm/opcode/push/class/private.rs

@@ -1,6 +1,6 @@
 use crate::{
     js_string,
-    object::PrivateElement,
+    object::{internal_methods::InternalMethodContext, PrivateElement},
     property::PropertyDescriptor,
     string::utf16,
     vm::{opcode::Operation, CompletionType},
@@ -29,7 +29,11 @@ impl PushClassPrivateMethod {
             .configurable(true)
             .build();
         method_object
-            .__define_own_property__(&utf16!("name").into(), desc, context)
+            .__define_own_property__(
+                &utf16!("name").into(),
+                desc,
+                &mut InternalMethodContext::new(context),
+            )
             .expect("failed to set name property on private method");
 
         let class = context.vm.pop();

boa_engine/src/vm/opcode/set/class_prototype.rs

@@ -1,5 +1,7 @@
 use crate::{
-    object::{JsObject, ObjectData, CONSTRUCTOR, PROTOTYPE},
+    object::{
+        internal_methods::InternalMethodContext, JsObject, ObjectData, CONSTRUCTOR, PROTOTYPE,
+    },
     property::PropertyDescriptorBuilder,
     vm::{opcode::Operation, CompletionType},
     Context, JsResult, JsValue,
@@ -63,7 +65,7 @@ impl Operation for SetClassPrototype {
                     .enumerable(false)
                     .configurable(true)
                     .build(),
-                context,
+                &mut InternalMethodContext::new(context),
             )
             .expect("cannot fail per spec");
 

boa_engine/src/vm/opcode/set/private.rs

@@ -122,7 +122,7 @@ impl SetPrivateMethod {
             .configurable(true)
             .build();
         value
-            .__define_own_property__(&js_string!("name").into(), desc, context)
+            .__define_own_property__(&js_string!("name").into(), desc, &mut context.into())
             .expect("failed to set name property on private method");
 
         let object = context.vm.pop();

boa_engine/src/vm/opcode/set/property.rs

@@ -2,6 +2,7 @@ use boa_macros::utf16;
 
 use crate::{
     builtins::function::set_function_name,
+    object::{internal_methods::InternalMethodContext, shape::slot::SlotAttributes},
     property::{PropertyDescriptor, PropertyKey},
     vm::{opcode::Operation, CompletionType},
     Context, JsNativeError, JsResult, JsString, JsValue,
@@ -25,19 +26,73 @@ impl SetPropertyByName {
             object.to_object(context)?
         };
 
-        let name: PropertyKey = context
+        let ic = &context.vm.frame().code_block().ic[index];
-            .vm
+        let mut slot = ic.slot();
-            .frame()
+        if slot.is_cachable() {
-            .code_block()
+            let object_borrowed = object.borrow();
-            .constant_string(index)
+            if ic.matches(object_borrowed.shape()) {
-            .into();
+                let slot_index = slot.index as usize;
+
+                if slot.attributes.is_accessor_descriptor() {
+                    let result = if slot.attributes.contains(SlotAttributes::PROTOTYPE) {
+                        let prototype = object_borrowed
+                            .properties()
+                            .shape
+                            .prototype()
+                            .expect("prototype should have value");
+                        let prototype = prototype.borrow();
+
+                        prototype.properties().storage[slot_index + 1].clone()
+                    } else {
+                        object_borrowed.properties().storage[slot_index + 1].clone()
+                    };
+
+                    drop(object_borrowed);
+                    if slot.attributes.has_set() && result.is_object() {
+                        result.as_object().expect("should contain getter").call(
+                            &receiver,
+                            &[value.clone()],
+                            context,
+                        )?;
+                    }
+                } else if slot.attributes.contains(SlotAttributes::PROTOTYPE) {
+                    let prototype = object_borrowed
+                        .properties()
+                        .shape
+                        .prototype()
+                        .expect("prototype should have value");
+                    let mut prototype = prototype.borrow_mut();
+
+                    prototype.properties_mut().storage[slot_index] = value.clone();
+                } else {
+                    drop(object_borrowed);
+                    let mut object_borrowed = object.borrow_mut();
+                    object_borrowed.properties_mut().storage[slot_index] = value.clone();
+                }
+                context.vm.push(value);
+                return Ok(CompletionType::Normal);
+            }
+        }
+
+        let name: PropertyKey = ic.name.clone().into();
 
+        let context = &mut InternalMethodContext::new(context);
         let succeeded = object.__set__(name.clone(), value.clone(), receiver, context)?;
         if !succeeded && context.vm.frame().code_block.strict() {
             return Err(JsNativeError::typ()
                 .with_message(format!("cannot set non-writable property: {name}"))
                 .into());
         }
+
+        slot = *context.slot();
+
+        // Cache the property.
+        if succeeded && slot.is_cachable() {
+            let ic = &context.vm.frame().code_block.ic[index];
+            let object_borrowed = object.borrow();
+            let shape = object_borrowed.shape();
+            ic.set(shape, slot);
+        }
         context.vm.stack.push(value);
         Ok(CompletionType::Normal)
     }
@@ -158,7 +213,8 @@ impl Operation for SetPropertyByValue {
         }
 
         // Slow path:
-        let succeeded = object.__set__(key.clone(), value.clone(), receiver, context)?;
+        let succeeded =
+            object.__set__(key.clone(), value.clone(), receiver, &mut context.into())?;
         if !succeeded && context.vm.frame().code_block.strict() {
             return Err(JsNativeError::typ()
                 .with_message(format!("cannot set non-writable property: {key}"))
@@ -188,7 +244,7 @@ impl SetPropertyGetterByName {
             .constant_string(index)
             .into();
         let set = object
-            .__get_own_property__(&name, context)?
+            .__get_own_property__(&name, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::set)
             .cloned();
@@ -200,7 +256,7 @@ impl SetPropertyGetterByName {
                 .enumerable(true)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -245,8 +301,9 @@ impl Operation for SetPropertyGetterByValue {
         let object = context.vm.pop();
         let object = object.to_object(context)?;
         let name = key.to_property_key(context)?;
+
         let set = object
-            .__get_own_property__(&name, context)?
+            .__get_own_property__(&name, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::set)
             .cloned();
@@ -258,7 +315,7 @@ impl Operation for SetPropertyGetterByValue {
                 .enumerable(true)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -282,8 +339,9 @@ impl SetPropertySetterByName {
             .code_block()
             .constant_string(index)
             .into();
+
         let get = object
-            .__get_own_property__(&name, context)?
+            .__get_own_property__(&name, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::get)
             .cloned();
@@ -295,7 +353,7 @@ impl SetPropertySetterByName {
                 .enumerable(true)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }
@@ -340,8 +398,9 @@ impl Operation for SetPropertySetterByValue {
         let object = context.vm.pop();
         let object = object.to_object(context)?;
         let name = key.to_property_key(context)?;
+
         let get = object
-            .__get_own_property__(&name, context)?
+            .__get_own_property__(&name, &mut InternalMethodContext::new(context))?
             .as_ref()
             .and_then(PropertyDescriptor::get)
             .cloned();
@@ -353,7 +412,7 @@ impl Operation for SetPropertySetterByValue {
                 .enumerable(true)
                 .configurable(true)
                 .build(),
-            context,
+            &mut InternalMethodContext::new(context),
         )?;
         Ok(CompletionType::Normal)
     }

boa_engine/src/vm/opcode/set/prototype.rs

@@ -1,4 +1,5 @@
 use crate::{
+    object::internal_methods::InternalMethodContext,
     vm::{opcode::Operation, CompletionType},
     Context, JsResult,
 };
@@ -29,7 +30,7 @@ impl Operation for SetPrototype {
 
         let object = object.as_object().expect("object is not an object");
         object
-            .__set_prototype_of__(prototype, context)
+            .__set_prototype_of__(prototype, &mut InternalMethodContext::new(context))
             .expect("cannot fail per spec");
 
         Ok(CompletionType::Normal)