Make Realm shareable between functions (#2801)

This Pull Request fixes #2317 and #1835, finally giving our engine proper realms 🥳.

It changes the following:

- Extracts the compile environment stack from `Realm` and into `Vm`.
- Adjusts the bytecompiler to accommodate this change.
- Adjusts `call/construct_internal` to accommodate this change. This also coincidentally fixed #2317, which I'm pretty happy about.
- Adjusts several APIs (`NativeJob`, `Realm`) and builtins (`eval`, initializers) to accommodate this change. 
- Adjusts `JsNativeError`s to hold a reference to the Realm from which they were created. This only affects errors created within calls to function objects. Native calls don't need to set the realm because it's inherited by the next outer active function object. TLDR: `JsError` API stays the same, we just set the origin Realm of errors in `JsObject::call/construct_internal`.

boa_engine/src/builtins/array/array_iterator.rs

@@ -13,6 +13,7 @@ use crate::{
     error::JsNativeError,
     object::{JsObject, ObjectData},
     property::{Attribute, PropertyNameKind},
+    realm::Realm,
     symbol::JsSymbol,
     Context, JsResult,
 };
@@ -35,11 +36,17 @@ pub struct ArrayIterator {
 }
 
 impl IntrinsicObject for ArrayIterator {
-    fn init(intrinsics: &Intrinsics) {
+    fn init(realm: &Realm) {
         let _timer = Profiler::global().start_event("ArrayIterator", "init");
 
-        BuiltInBuilder::with_intrinsic::<Self>(intrinsics)
-            .prototype(intrinsics.objects().iterator_prototypes().iterator())
+        BuiltInBuilder::with_intrinsic::<Self>(realm)
+            .prototype(
+                realm
+                    .intrinsics()
+                    .objects()
+                    .iterator_prototypes()
+                    .iterator(),
+            )
             .static_method(Self::next, "next", 0)
             .static_property(
                 JsSymbol::to_string_tag(),

boa_engine/src/builtins/array/mod.rs

@@ -22,6 +22,7 @@ use crate::{
     js_string,
     object::{internal_methods::get_prototype_from_constructor, JsObject, ObjectData, CONSTRUCTOR},
     property::{Attribute, PropertyDescriptor, PropertyNameKind},
+    realm::Realm,
     symbol::JsSymbol,
     value::{IntegerOrInfinity, JsValue},
     Context, JsArgs, JsResult,
@@ -40,26 +41,28 @@ mod tests;
 pub(crate) struct Array;
 
 impl IntrinsicObject for Array {
-    fn init(intrinsics: &Intrinsics) {
+    fn init(realm: &Realm) {
         let _timer = Profiler::global().start_event(Self::NAME, "init");
 
         let symbol_iterator = JsSymbol::iterator();
         let symbol_unscopables = JsSymbol::unscopables();
 
-        let get_species = BuiltInBuilder::new(intrinsics)
+        let get_species = BuiltInBuilder::new(realm)
             .callable(Self::get_species)
             .name("get [Symbol.species]")
             .build();
 
-        let values_function =
-            BuiltInBuilder::with_object(intrinsics, intrinsics.objects().array_prototype_values())
-                .callable(Self::values)
-                .name("values")
-                .build();
+        let values_function = BuiltInBuilder::with_object(
+            realm,
+            realm.intrinsics().objects().array_prototype_values(),
+        )
+        .callable(Self::values)
+        .name("values")
+        .build();
 
         let unscopables_object = Self::unscopables_object();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(intrinsics)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm)
             .static_accessor(
                 JsSymbol::species(),
                 Some(get_species),
@@ -369,12 +372,14 @@ impl Array {
         // 4. If IsConstructor(C) is true, then
         if let Some(c) = c.as_constructor() {
             // a. Let thisRealm be the current Realm Record.
-            let this_realm = &context.intrinsics().clone();
+            let this_realm = context.realm().clone();
             // b. Let realmC be ? GetFunctionRealm(C).
-            let realm_c = &c.get_function_realm(context)?;
+            let realm_c = c.get_function_realm(context)?;
 
             // c. If thisRealm and realmC are not the same Realm Record, then
-            if this_realm != realm_c && *c == realm_c.constructors().array().constructor() {
+            if this_realm != realm_c
+                && *c == realm_c.intrinsics().constructors().array().constructor()
+            {
                 // i. If SameValue(C, realmC.[[Intrinsics]].[[%Array%]]) is true, set C to undefined.
                 // Note: fast path to step 6.
                 return Self::array_create(length, None, context);

boa_engine/src/builtins/array_buffer/mod.rs

@@ -16,6 +16,7 @@ use crate::{
     error::JsNativeError,
     object::{internal_methods::get_prototype_from_constructor, JsObject, ObjectData},
     property::Attribute,
+    realm::Realm,
     string::utf16,
     symbol::JsSymbol,
     value::{IntegerOrInfinity, Numeric},
@@ -47,22 +48,22 @@ impl ArrayBuffer {
 }
 
 impl IntrinsicObject for ArrayBuffer {
-    fn init(intrinsics: &Intrinsics) {
+    fn init(realm: &Realm) {
         let _timer = Profiler::global().start_event(Self::NAME, "init");
 
         let flag_attributes = Attribute::CONFIGURABLE | Attribute::NON_ENUMERABLE;
 
-        let get_species = BuiltInBuilder::new(intrinsics)
+        let get_species = BuiltInBuilder::new(realm)
             .callable(Self::get_species)
             .name("get [Symbol.species]")
             .build();
 
-        let get_byte_length = BuiltInBuilder::new(intrinsics)
+        let get_byte_length = BuiltInBuilder::new(realm)
             .callable(Self::get_byte_length)
             .name("get byteLength")
             .build();
 
-        BuiltInBuilder::from_standard_constructor::<Self>(intrinsics)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm)
             .accessor(
                 utf16!("byteLength"),
                 Some(get_byte_length),

boa_engine/src/builtins/async_function/mod.rs

@@ -11,6 +11,7 @@ use crate::{
     builtins::{function::BuiltInFunctionObject, BuiltInObject},
     context::intrinsics::{Intrinsics, StandardConstructor, StandardConstructors},
     property::Attribute,
+    realm::Realm,
     symbol::JsSymbol,
     Context, JsResult, JsValue,
 };
@@ -23,12 +24,14 @@ use super::{BuiltInBuilder, BuiltInConstructor, IntrinsicObject};
 pub struct AsyncFunction;
 
 impl IntrinsicObject for AsyncFunction {
-    fn init(intrinsics: &Intrinsics) {
+    fn init(realm: &Realm) {
         let _timer = Profiler::global().start_event(Self::NAME, "init");
 
-        BuiltInBuilder::from_standard_constructor::<Self>(intrinsics)
-            .prototype(intrinsics.constructors().function().constructor())
-            .inherits(Some(intrinsics.constructors().function().prototype()))
+        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+            .prototype(realm.intrinsics().constructors().function().constructor())
+            .inherits(Some(
+                realm.intrinsics().constructors().function().prototype(),
+            ))
             .property(
                 JsSymbol::to_string_tag(),
                 Self::NAME,

boa_engine/src/builtins/async_generator/mod.rs

@@ -15,6 +15,7 @@ use crate::{
     native_function::NativeFunction,
     object::{FunctionObjectBuilder, JsObject, CONSTRUCTOR},
     property::Attribute,
+    realm::Realm,
     symbol::JsSymbol,
     value::JsValue,
     vm::GeneratorResumeKind,
@@ -66,11 +67,17 @@ pub struct AsyncGenerator {
 }
 
 impl IntrinsicObject for AsyncGenerator {
-    fn init(intrinsics: &Intrinsics) {
+    fn init(realm: &Realm) {
         let _timer = Profiler::global().start_event(Self::NAME, "init");
 
-        BuiltInBuilder::with_intrinsic::<Self>(intrinsics)
-            .prototype(intrinsics.objects().iterator_prototypes().async_iterator())
+        BuiltInBuilder::with_intrinsic::<Self>(realm)
+            .prototype(
+                realm
+                    .intrinsics()
+                    .objects()
+                    .iterator_prototypes()
+                    .async_iterator(),
+            )
             .static_method(Self::next, "next", 1)
             .static_method(Self::r#return, "return", 1)
             .static_method(Self::throw, "throw", 1)
@@ -81,7 +88,8 @@ impl IntrinsicObject for AsyncGenerator {
             )
             .static_property(
                 CONSTRUCTOR,
-                intrinsics
+                realm
+                    .intrinsics()
                     .constructors()
                     .async_generator_function()
                     .prototype(),
@@ -399,6 +407,7 @@ impl AsyncGenerator {
         next: &AsyncGeneratorRequest,
         completion: JsResult<JsValue>,
         done: bool,
+        realm: Option<Realm>,
         context: &mut Context<'_>,
     ) {
         // 1. Let queue be generator.[[AsyncGeneratorQueue]].
@@ -422,15 +431,24 @@ impl AsyncGenerator {
             Ok(value) => {
                 // a. Assert: completion.[[Type]] is normal.
 
-                // TODO: Realm handling not implemented yet.
                 // b. If realm is present, then
-                // i. Let oldRealm be the running execution context's Realm.
-                // ii. Set the running execution context's Realm to realm.
-                // iii. Let iteratorResult be CreateIterResultObject(value, done).
-                // iv. Set the running execution context's Realm to oldRealm.
-                // c. Else,
-                // i. Let iteratorResult be CreateIterResultObject(value, done).
-                let iterator_result = create_iter_result_object(value, done, context);
+                let iterator_result = if let Some(realm) = realm {
+                    // i. Let oldRealm be the running execution context's Realm.
+                    // ii. Set the running execution context's Realm to realm.
+                    let old_realm = context.enter_realm(realm);
+
+                    // iii. Let iteratorResult be CreateIterResultObject(value, done).
+                    let iterator_result = create_iter_result_object(value, done, context);
+
+                    // iv. Set the running execution context's Realm to oldRealm.
+                    context.enter_realm(old_realm);
+
+                    iterator_result
+                } else {
+                    // c. Else,
+                    // i. Let iteratorResult be CreateIterResultObject(value, done).
+                    create_iter_result_object(value, done, context)
+                };
 
                 // d. Perform ! Call(promiseCapability.[[Resolve]], undefined, « iteratorResult »).
                 promise_capability
@@ -474,18 +492,15 @@ impl AsyncGenerator {
 
         // 6. Push genContext onto the execution context stack; genContext is now the running execution context.
         std::mem::swap(
-            &mut context.realm.environments,
+            &mut context.vm.environments,
             &mut generator_context.environments,
         );
         std::mem::swap(&mut context.vm.stack, &mut generator_context.stack);
         std::mem::swap(
             &mut context.vm.active_function,
             &mut generator_context.active_function,
         );
-        std::mem::swap(
-            &mut context.realm.intrinsics,
-            &mut generator_context.realm_intrinsics,
-        );
+        let old_realm = context.enter_realm(generator_context.realm.clone());
 
         context.vm.push_frame(generator_context.call_frame.clone());
 
@@ -508,7 +523,7 @@ impl AsyncGenerator {
         let result = context.run();
 
         std::mem::swap(
-            &mut context.realm.environments,
+            &mut context.vm.environments,
             &mut generator_context.environments,
         );
         std::mem::swap(&mut context.vm.stack, &mut generator_context.stack);
@@ -517,10 +532,7 @@ impl AsyncGenerator {
             &mut context.vm.active_function,
             &mut generator_context.active_function,
         );
-        std::mem::swap(
-            &mut context.realm.intrinsics,
-            &mut generator_context.realm_intrinsics,
-        );
+        context.enter_realm(old_realm);
 
         generator
             .borrow_mut()
@@ -575,7 +587,7 @@ impl AsyncGenerator {
                 gen.context = None;
                 let next = gen.queue.pop_front().expect("queue must not be empty");
                 drop(generator_borrow_mut);
-                Self::complete_step(&next, Err(value), true, context);
+                Self::complete_step(&next, Err(value), true, None, context);
                 Self::drain_queue(&generator, context);
                 return;
             }
@@ -604,7 +616,7 @@ impl AsyncGenerator {
                     let result = Ok(args.get_or_undefined(0).clone());
 
                     // c. Perform AsyncGeneratorCompleteStep(generator, result, true).
-                    Self::complete_step(&next, result, true, context);
+                    Self::complete_step(&next, result, true, None, context);
 
                     // d. Perform AsyncGeneratorDrainQueue(generator).
                     Self::drain_queue(generator, context);
@@ -640,7 +652,7 @@ impl AsyncGenerator {
                     // c. Perform AsyncGeneratorCompleteStep(generator, result, true).
                     let next = gen.queue.pop_front().expect("must have one entry");
                     drop(generator_borrow_mut);
-                    Self::complete_step(&next, result, true, context);
+                    Self::complete_step(&next, result, true, None, context);
 
                     // d. Perform AsyncGeneratorDrainQueue(generator).
                     Self::drain_queue(generator, context);
@@ -721,7 +733,7 @@ impl AsyncGenerator {
 
                     // ii. Perform AsyncGeneratorCompleteStep(generator, completion, true).
                     let next = queue.pop_front().expect("must have entry");
-                    Self::complete_step(&next, completion, true, context);
+                    Self::complete_step(&next, completion, true, None, context);
 
                     // iii. If queue is empty, set done to true.
                     if queue.is_empty() {

boa_engine/src/builtins/async_generator_function/mod.rs

@@ -10,6 +10,7 @@ use crate::{
     context::intrinsics::{Intrinsics, StandardConstructor, StandardConstructors},
     object::{JsObject, PROTOTYPE},
     property::Attribute,
+    realm::Realm,
     symbol::JsSymbol,
     value::JsValue,
     Context, JsResult,
@@ -23,15 +24,17 @@ use super::{BuiltInBuilder, BuiltInConstructor, IntrinsicObject};
 pub struct AsyncGeneratorFunction;
 
 impl IntrinsicObject for AsyncGeneratorFunction {
-    fn init(intrinsics: &Intrinsics) {
+    fn init(realm: &Realm) {
         let _timer = Profiler::global().start_event(Self::NAME, "init");
 
-        BuiltInBuilder::from_standard_constructor::<Self>(intrinsics)
-            .inherits(Some(intrinsics.constructors().function().prototype()))
+        BuiltInBuilder::from_standard_constructor::<Self>(realm)
+            .inherits(Some(
+                realm.intrinsics().constructors().function().prototype(),
+            ))
             .constructor_attributes(Attribute::CONFIGURABLE)
             .property(
                 PROTOTYPE,
-                intrinsics.objects().async_generator(),
+                realm.intrinsics().objects().async_generator(),
                 Attribute::CONFIGURABLE,
             )
             .property(

boa_engine/src/builtins/bigint/mod.rs

@@ -18,6 +18,7 @@ use crate::{
     error::JsNativeError,
     object::JsObject,
     property::Attribute,
+    realm::Realm,
     symbol::JsSymbol,
     value::{IntegerOrInfinity, PreferredType},
     Context, JsArgs, JsBigInt, JsResult, JsValue,
@@ -35,10 +36,10 @@ mod tests;
 pub struct BigInt;
 
 impl IntrinsicObject for BigInt {
-    fn init(intrinsics: &Intrinsics) {
+    fn init(realm: &Realm) {
         let _timer = Profiler::global().start_event(Self::NAME, "init");
 
-        BuiltInBuilder::from_standard_constructor::<Self>(intrinsics)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm)
             .method(Self::to_string, "toString", 0)
             .method(Self::value_of, "valueOf", 0)
             .static_method(Self::as_int_n, "asIntN", 2)

boa_engine/src/builtins/boolean/mod.rs

@@ -17,6 +17,7 @@ use crate::{
     context::intrinsics::{Intrinsics, StandardConstructor, StandardConstructors},
     error::JsNativeError,
     object::{internal_methods::get_prototype_from_constructor, JsObject, ObjectData},
+    realm::Realm,
     Context, JsResult, JsValue,
 };
 use boa_profiler::Profiler;
@@ -28,10 +29,10 @@ use super::{BuiltInBuilder, BuiltInConstructor, IntrinsicObject};
 pub(crate) struct Boolean;
 
 impl IntrinsicObject for Boolean {
-    fn init(intrinsics: &Intrinsics) {
+    fn init(realm: &Realm) {
         let _timer = Profiler::global().start_event(Self::NAME, "init");
 
-        BuiltInBuilder::from_standard_constructor::<Self>(intrinsics)
+        BuiltInBuilder::from_standard_constructor::<Self>(realm)
             .method(Self::to_string, "toString", 0)
             .method(Self::value_of, "valueOf", 0)
             .build();