Implement pseudo-property import.meta (#2956)

* Implement pseudo-property `import.meta`

* Apply review

boa_ast/src/expression/mod.rs

@@ -133,7 +133,9 @@ pub enum Expression {
     /// The `new.target` pseudo-property expression.
     NewTarget,
 
-    // TODO: import.meta
+    /// The `import.meta` pseudo-property expression.
+    ImportMeta,
+
     /// See [`Assign`].
     Assign(Assign),
 
@@ -197,6 +199,7 @@ impl Expression {
             Self::ImportCall(impc) => impc.to_interned_string(interner),
             Self::Optional(opt) => opt.to_interned_string(interner),
             Self::NewTarget => "new.target".to_owned(),
+            Self::ImportMeta => "import.meta".to_owned(),
             Self::TaggedTemplate(tag) => tag.to_interned_string(interner),
             Self::Assign(assign) => assign.to_interned_string(interner),
             Self::Unary(unary) => unary.to_interned_string(interner),
@@ -316,7 +319,7 @@ impl VisitWith for Expression {
             Self::Yield(y) => visitor.visit_yield(y),
             Self::Parenthesized(e) => visitor.visit_parenthesized(e),
             Self::FormalParameterList(fpl) => visitor.visit_formal_parameter_list(fpl),
-            Self::This | Self::NewTarget => {
+            Self::This | Self::NewTarget | Self::ImportMeta => {
                 // do nothing; can be handled as special case by visitor
                 ControlFlow::Continue(())
             }
@@ -358,7 +361,7 @@ impl VisitWith for Expression {
             Self::Yield(y) => visitor.visit_yield_mut(y),
             Self::Parenthesized(e) => visitor.visit_parenthesized_mut(e),
             Self::FormalParameterList(fpl) => visitor.visit_formal_parameter_list_mut(fpl),
-            Self::This | Self::NewTarget => {
+            Self::This | Self::NewTarget | Self::ImportMeta => {
                 // do nothing; can be handled as special case by visitor
                 ControlFlow::Continue(())
             }

boa_engine/src/bytecompiler/expression/mod.rs

@@ -329,7 +329,12 @@ impl ByteCompiler<'_, '_> {
             }
             Expression::NewTarget => {
                 if use_expr {
-                    self.emit_opcode(Opcode::PushNewTarget);
+                    self.emit_opcode(Opcode::NewTarget);
+                }
+            }
+            Expression::ImportMeta => {
+                if use_expr {
+                    self.emit_opcode(Opcode::ImportMeta);
                 }
             }
             Expression::Optional(opt) => {

boa_engine/src/module/mod.rs

@@ -122,8 +122,8 @@ pub trait ModuleLoader {
     /// [final]: https://tc39.es/ecma262/#sec-hostfinalizeimportmeta
     fn init_import_meta(
         &self,
-        _import_meta: JsObject,
-        _module: Module,
+        _import_meta: &JsObject,
+        _module: &Module,
         _context: &mut Context<'_>,
     ) {
     }

boa_engine/src/module/source.rs

@@ -1769,6 +1769,11 @@ impl SourceTextModule {
     pub(crate) fn loaded_modules(&self) -> &GcRefCell<FxHashMap<Sym, Module>> {
         &self.inner.loaded_modules
     }
+
+    /// Gets the import meta object of this module.
+    pub(crate) fn import_meta(&self) -> &GcRefCell<Option<JsObject>> {
+        &self.inner.import_meta
+    }
 }
 
 /// Abstract operation [`AsyncModuleExecutionFulfilled ( module )`][spec].

boa_engine/src/vm/code_block.rs

@@ -500,7 +500,8 @@ impl CodeBlock {
             | Opcode::PushClassField
             | Opcode::SuperCallDerived
             | Opcode::Await
-            | Opcode::PushNewTarget
+            | Opcode::NewTarget
+            | Opcode::ImportMeta
             | Opcode::SuperCallPrepare
             | Opcode::CallEvalSpread
             | Opcode::CallSpread

boa_engine/src/vm/flowgraph/mod.rs

@@ -584,7 +584,8 @@ impl CodeBlock {
                 | Opcode::PushClassField
                 | Opcode::SuperCallDerived
                 | Opcode::Await
-                | Opcode::PushNewTarget
+                | Opcode::NewTarget
+                | Opcode::ImportMeta
                 | Opcode::CallEvalSpread
                 | Opcode::CallSpread
                 | Opcode::NewSpread

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

@@ -0,0 +1,95 @@
+use std::unreachable;
+
+use crate::{
+    module::ModuleKind,
+    vm::{opcode::Operation, ActiveRunnable, CompletionType},
+    Context, JsObject, JsResult, JsValue,
+};
+
+/// `NewTarget` implements the Opcode Operation for `Opcode::NewTarget`
+///
+/// Operation:
+///  - Push the current new target to the stack.
+#[derive(Debug, Clone, Copy)]
+pub(crate) struct NewTarget;
+
+impl Operation for NewTarget {
+    const NAME: &'static str = "NewTarget";
+    const INSTRUCTION: &'static str = "INST - NewTarget";
+
+    fn execute(context: &mut Context<'_>) -> JsResult<CompletionType> {
+        let new_target = if let Some(new_target) = context
+            .vm
+            .environments
+            .get_this_environment()
+            .as_function()
+            .and_then(|env| env.slots().new_target().cloned())
+        {
+            new_target.into()
+        } else {
+            JsValue::undefined()
+        };
+        context.vm.push(new_target);
+        Ok(CompletionType::Normal)
+    }
+}
+
+/// `ImportMeta` implements the Opcode Operation for `Opcode::ImportMeta`
+///
+/// Operation:
+///  - Push the current `import.meta` to the stack
+#[derive(Debug, Clone, Copy)]
+pub(crate) struct ImportMeta;
+
+impl Operation for ImportMeta {
+    const NAME: &'static str = "ImportMeta";
+    const INSTRUCTION: &'static str = "INST - ImportMeta";
+
+    fn execute(context: &mut Context<'_>) -> JsResult<CompletionType> {
+        // Meta Properties
+        //
+        // ImportMeta : import . meta
+        //
+        // https://tc39.es/ecma262/#sec-meta-properties
+
+        // 1. Let module be GetActiveScriptOrModule().
+
+        let Some(ActiveRunnable::Module(module)) = context.vm.active_runnable.clone() else {
+            unreachable!("2. Assert: module is a Source Text Module Record.");
+        };
+
+        let ModuleKind::SourceText(src) = module.kind() else {
+            unreachable!("2. Assert: module is a Source Text Module Record.");
+        };
+
+        // 3. Let importMeta be module.[[ImportMeta]].
+        // 4. If importMeta is empty, then
+        // 5. Else,
+        //     a. Assert: importMeta is an Object.
+        let import_meta = src
+            .import_meta()
+            .borrow_mut()
+            .get_or_insert_with(|| {
+                // a. Set importMeta to OrdinaryObjectCreate(null).
+                let import_meta = JsObject::with_null_proto();
+
+                // b. Let importMetaValues be HostGetImportMetaProperties(module).
+                // c. For each Record { [[Key]], [[Value]] } p of importMetaValues, do
+                //     i. Perform ! CreateDataPropertyOrThrow(importMeta, p.[[Key]], p.[[Value]]).
+                // d. Perform HostFinalizeImportMeta(importMeta, module).
+                context
+                    .module_loader()
+                    .init_import_meta(&import_meta, &module, context);
+
+                // e. Set module.[[ImportMeta]] to importMeta.
+                import_meta
+            })
+            .clone();
+
+        //     b. Return importMeta.
+        //     f. Return importMeta.
+        context.vm.push(import_meta);
+
+        Ok(CompletionType::Normal)
+    }
+}

boa_engine/src/vm/opcode/mod.rs

@@ -18,6 +18,7 @@ mod generator;
 mod get;
 mod iteration;
 mod jump;
+mod meta;
 mod new;
 mod nop;
 mod pop;
@@ -62,6 +63,8 @@ pub(crate) use iteration::*;
 #[doc(inline)]
 pub(crate) use jump::*;
 #[doc(inline)]
+pub(crate) use meta::*;
+#[doc(inline)]
 pub(crate) use new::*;
 #[doc(inline)]
 pub(crate) use nop::*;
@@ -1602,8 +1605,15 @@ generate_impl! {
         ///
         /// Operands:
         ///
-        /// Stack: **=>** new_target
-        PushNewTarget,
+        /// Stack: **=>** `new.target`
+        NewTarget,
+
+        /// Push the current `import.meta` to the stack.
+        ///
+        /// Operands:
+        ///
+        /// Stack: **=>** `import.meta`
+        ImportMeta,
 
         /// Pushes `true` to the stack if the top stack value is an object, or `false` otherwise.
         ///

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

@@ -7,15 +7,13 @@ pub(crate) mod array;
 pub(crate) mod class;
 pub(crate) mod environment;
 pub(crate) mod literal;
-pub(crate) mod new_target;
 pub(crate) mod numbers;
 pub(crate) mod object;
 
 pub(crate) use array::*;
 pub(crate) use class::*;
 pub(crate) use environment::*;
 pub(crate) use literal::*;
-pub(crate) use new_target::*;
 pub(crate) use numbers::*;
 pub(crate) use object::*;
 

boa_interner/src/sym.rs

@@ -148,5 +148,6 @@ static_syms! {
     "__proto__",
     "name",
     "await",
-    ("*default*", DEFAULT_EXPORT)
+    ("*default*", DEFAULT_EXPORT),
+    "meta"
 }

boa_parser/src/parser/expression/left_hand_side/member.rs

@@ -72,13 +72,53 @@ where
         cursor.set_goal(InputElement::RegExp);
 
         let token = cursor.peek(0, interner).or_abrupt()?;
+        let position = token.span().start();
         let mut lhs = match token.kind() {
-            TokenKind::Keyword((Keyword::New | Keyword::Super, true)) => {
+            TokenKind::Keyword((Keyword::New | Keyword::Super | Keyword::Import, true)) => {
                 return Err(Error::general(
                     "keyword must not contain escaped characters",
                     token.span().start(),
                 ));
             }
+            TokenKind::Keyword((Keyword::Import, false)) => {
+                cursor.advance(interner);
+
+                cursor.expect(
+                    TokenKind::Punctuator(Punctuator::Dot),
+                    "import.meta",
+                    interner,
+                )?;
+
+                let token = cursor.next(interner).or_abrupt()?;
+
+                match token.kind() {
+                    TokenKind::IdentifierName((Sym::META, ContainsEscapeSequence(ces))) => {
+                        if *ces {
+                            return Err(Error::general(
+                                "`import.meta` cannot contain escaped characters",
+                                token.span().start(),
+                            ));
+                        }
+                    }
+                    _ => {
+                        return Err(Error::expected(
+                            ["property `meta`".into()],
+                            token.to_string(interner),
+                            token.span(),
+                            "import.meta",
+                        ));
+                    }
+                }
+
+                if !cursor.module() {
+                    return Err(Error::general(
+                        "invalid `import.meta` expression outside a module",
+                        position,
+                    ));
+                }
+
+                ast::Expression::ImportMeta
+            }
             TokenKind::Keyword((Keyword::New, false)) => {
                 cursor.advance(interner);