Fix tagged template creation

boa_ast/src/expression/tagged_template.rs

@@ -21,6 +21,7 @@ pub struct TaggedTemplate {
     raws: Box<[Sym]>,
     cookeds: Box<[Option<Sym>]>,
     exprs: Box<[Expression]>,
+    identifier: u64,
 }
 
 impl TaggedTemplate {
@@ -33,12 +34,14 @@ impl TaggedTemplate {
         raws: Box<[Sym]>,
         cookeds: Box<[Option<Sym>]>,
         exprs: Box<[Expression]>,
+        identifier: u64,
     ) -> Self {
         Self {
             tag: tag.into(),
             raws,
             cookeds,
             exprs,
+            identifier,
         }
     }
 
@@ -69,6 +72,13 @@ impl TaggedTemplate {
     pub const fn exprs(&self) -> &[Expression] {
         &self.exprs
     }
+
+    /// Gets the unique identifier of the template.
+    #[inline]
+    #[must_use]
+    pub const fn identifier(&self) -> u64 {
+        self.identifier
+    }
 }
 
 impl ToInternedString for TaggedTemplate {

boa_engine/src/builtins/eval/mod.rs

@@ -112,6 +112,7 @@ impl Eval {
         //     c. If script Contains ScriptBody is false, return undefined.
         //     d. Let body be the ScriptBody of script.
         let mut parser = Parser::new(Source::from_bytes(&x));
+        parser.set_identifier(context.next_parser_identifier());
         if strict {
             parser.set_strict();
         }

boa_engine/src/builtins/function/mod.rs

@@ -586,17 +586,22 @@ impl BuiltInFunctionObject {
                 let parameters = parameters.join(utf16!(","));
 
                 // TODO: make parser generic to u32 iterators
-                let parameters =
-                    match Parser::new(Source::from_bytes(&String::from_utf16_lossy(&parameters)))
-                        .parse_formal_parameters(context.interner_mut(), generator, r#async)
-                    {
-                        Ok(parameters) => parameters,
-                        Err(e) => {
-                            return Err(JsNativeError::syntax()
-                                .with_message(format!("failed to parse function parameters: {e}"))
-                                .into())
-                        }
-                    };
+                let parameters = String::from_utf16_lossy(&parameters);
+                let mut parser = Parser::new(Source::from_bytes(&parameters));
+                parser.set_identifier(context.next_parser_identifier());
+
+                let parameters = match parser.parse_formal_parameters(
+                    context.interner_mut(),
+                    generator,
+                    r#async,
+                ) {
+                    Ok(parameters) => parameters,
+                    Err(e) => {
+                        return Err(JsNativeError::syntax()
+                            .with_message(format!("failed to parse function parameters: {e}"))
+                            .into())
+                    }
+                };
 
                 if generator && contains(&parameters, ContainsSymbol::YieldExpression) {
                     return Err(JsNativeError::syntax().with_message(
@@ -626,11 +631,11 @@ impl BuiltInFunctionObject {
             let body = b"\n".chain(body_arg.as_bytes()).chain(b"\n".as_slice());
 
             // TODO: make parser generic to u32 iterators
-            let body = match Parser::new(Source::from_reader(body, None)).parse_function_body(
-                context.interner_mut(),
-                generator,
-                r#async,
-            ) {
+            let mut parser = Parser::new(Source::from_reader(body, None));
+            parser.set_identifier(context.next_parser_identifier());
+
+            let body = match parser.parse_function_body(context.interner_mut(), generator, r#async)
+            {
                 Ok(statement_list) => statement_list,
                 Err(e) => {
                     return Err(JsNativeError::syntax()

boa_engine/src/bytecompiler/expression/mod.rs

@@ -17,7 +17,6 @@ use boa_ast::{
     },
     Expression,
 };
-use boa_interner::Sym;
 
 impl ByteCompiler<'_, '_> {
     fn compile_literal(&mut self, lit: &AstLiteral, use_expr: bool) {
@@ -255,31 +254,29 @@ impl ByteCompiler<'_, '_> {
                     }
                 }
 
-                self.emit_opcode(Opcode::PushNewArray);
-                for cooked in template.cookeds() {
+                let site = template.identifier();
+                let count = template.cookeds().len() as u32;
+
+                let jump_label = self.emit_opcode_with_operand(Opcode::TemplateLookup);
+                self.emit_u64(site);
+
+                for (cooked, raw) in template.cookeds().iter().zip(template.raws()) {
                     if let Some(cooked) = cooked {
                         self.emit_push_literal(Literal::String(
                             self.interner().resolve_expect(*cooked).into_common(false),
                         ));
                     } else {
                         self.emit_opcode(Opcode::PushUndefined);
                     }
-                    self.emit_opcode(Opcode::PushValueToArray);
-                }
-                self.emit_opcode(Opcode::Dup);
-                self.emit_opcode(Opcode::Dup);
-
-                self.emit_opcode(Opcode::PushNewArray);
-                for raw in template.raws() {
                     self.emit_push_literal(Literal::String(
                         self.interner().resolve_expect(*raw).into_common(false),
                     ));
-                    self.emit_opcode(Opcode::PushValueToArray);
                 }
 
-                let index = self.get_or_insert_name(Sym::RAW.into());
-                self.emit(Opcode::SetPropertyByName, &[index]);
-                self.emit(Opcode::Pop, &[]);
+                self.emit(Opcode::TemplateCreate, &[count]);
+                self.emit_u64(site);
+
+                self.patch_jump(jump_label);
 
                 for expr in template.exprs() {
                     self.compile_expr(expr, true);

boa_engine/src/context/mod.rs

@@ -112,6 +112,9 @@ pub struct Context<'host> {
 
     optimizer_options: OptimizerOptions,
     root_shape: SharedShape,
+
+    /// Unique identifier for each parser instance used during the context lifetime.
+    parser_identifier: u32,
 }
 
 impl std::fmt::Debug for Context<'_> {
@@ -230,6 +233,7 @@ impl<'host> Context<'host> {
     ) -> Result<StatementList, ParseError> {
         let _timer = Profiler::global().start_event("Script parsing", "Main");
         let mut parser = Parser::new(src);
+        parser.set_identifier(self.next_parser_identifier());
         if self.strict {
             parser.set_strict();
         }
@@ -247,6 +251,7 @@ impl<'host> Context<'host> {
     ) -> Result<ModuleItemList, ParseError> {
         let _timer = Profiler::global().start_event("Module parsing", "Main");
         let mut parser = Parser::new(src);
+        parser.set_identifier(self.next_parser_identifier());
         parser.parse_module(&mut self.interner)
     }
 
@@ -656,6 +661,12 @@ impl Context<'_> {
         std::mem::swap(&mut self.realm, realm);
     }
 
+    /// Get and increment the parser identifier.
+    pub(crate) fn next_parser_identifier(&mut self) -> u32 {
+        self.parser_identifier += 1;
+        self.parser_identifier
+    }
+
     /// `CanDeclareGlobalFunction ( N )`
     ///
     /// More information:
@@ -1025,6 +1036,7 @@ impl<'icu, 'hooks, 'queue> ContextBuilder<'icu, 'hooks, 'queue> {
             }),
             optimizer_options: OptimizerOptions::OPTIMIZE_ALL,
             root_shape,
+            parser_identifier: 0,
         };
 
         builtins::set_default_global_bindings(&mut context)?;

boa_engine/src/realm.rs

@@ -6,15 +6,15 @@
 //!
 //! A realm is represented in this implementation as a Realm struct with the fields specified from the spec.
 
-use std::fmt;
-
 use crate::{
     context::{intrinsics::Intrinsics, HostHooks},
     environments::DeclarativeEnvironment,
     object::{shape::shared_shape::SharedShape, JsObject},
 };
-use boa_gc::{Finalize, Gc, Trace};
+use boa_gc::{Finalize, Gc, GcRefCell, Trace};
 use boa_profiler::Profiler;
+use rustc_hash::FxHashMap;
+use std::fmt;
 
 /// Representation of a Realm.
 ///
@@ -49,6 +49,7 @@ struct Inner {
     environment: Gc<DeclarativeEnvironment>,
     global_object: JsObject,
     global_this: JsObject,
+    template_map: GcRefCell<FxHashMap<u64, JsObject>>,
 }
 
 impl Realm {
@@ -69,6 +70,7 @@ impl Realm {
                 environment: Gc::new(DeclarativeEnvironment::new_global()),
                 global_object,
                 global_this,
+                template_map: GcRefCell::new(FxHashMap::default()),
             }),
         };
 
@@ -103,4 +105,12 @@ impl Realm {
             bindings.resize(binding_number, None);
         }
     }
+
+    pub(crate) fn push_template(&self, site: u64, template: JsObject) {
+        self.inner.template_map.borrow_mut().insert(site, template);
+    }
+
+    pub(crate) fn lookup_template(&self, site: u64) -> Option<JsObject> {
+        self.inner.template_map.borrow().get(&site).cloned()
+    }
 }

boa_engine/src/vm/code_block.rs

@@ -300,6 +300,13 @@ impl CodeBlock {
                 *pc += size_of::<u32>();
                 format!("{operand1}, {operand2}")
             }
+            Opcode::TemplateLookup | Opcode::TemplateCreate => {
+                let operand1 = self.read::<u32>(*pc);
+                *pc += size_of::<u32>();
+                let operand2 = self.read::<u64>(*pc);
+                *pc += size_of::<u64>();
+                format!("{operand1}, {operand2}")
+            }
             Opcode::GeneratorAsyncDelegateResume => {
                 let operand1 = self.read::<u32>(*pc);
                 *pc += size_of::<u32>();

boa_engine/src/vm/flowgraph/mod.rs

@@ -148,6 +148,16 @@ impl CodeBlock {
                     graph.add_node(previous_pc, NodeShape::None, label.into(), Color::Red);
                     graph.add_edge(previous_pc, pc, None, Color::None, EdgeStyle::Line);
                 }
+                Opcode::TemplateLookup | Opcode::TemplateCreate => {
+                    let start_address = self.read::<u32>(pc);
+                    pc += size_of::<u32>();
+                    let end_address = self.read::<u64>(pc);
+                    pc += size_of::<u64>();
+
+                    let label = format!("{opcode_str} {start_address}, {end_address}");
+                    graph.add_node(previous_pc, NodeShape::None, label.into(), Color::Red);
+                    graph.add_edge(previous_pc, pc, None, Color::None, EdgeStyle::Line);
+                }
                 Opcode::Break => {
                     let jump_operand = self.read::<u32>(pc);
                     pc += size_of::<u32>();

boa_engine/src/vm/opcode/mod.rs

@@ -27,6 +27,7 @@ mod rest_parameter;
 mod set;
 mod swap;
 mod switch;
+mod templates;
 mod to;
 mod unary_ops;
 mod value;
@@ -79,6 +80,8 @@ pub(crate) use swap::*;
 #[doc(inline)]
 pub(crate) use switch::*;
 #[doc(inline)]
+pub(crate) use templates::*;
+#[doc(inline)]
 pub(crate) use to::*;
 #[doc(inline)]
 pub(crate) use unary_ops::*;
@@ -1602,6 +1605,20 @@ generate_impl! {
         /// Stack: value **=>** is_object
         IsObject,
 
+        /// Lookup if a tagged template object is cached and skip the creation if it is.
+        ///
+        /// Operands: jump: `u32`, site: `u64`
+        ///
+        /// Stack: **=>** template (if cached)
+        TemplateLookup,
+
+        /// Create a new tagged template object and cache it.
+        ///
+        /// Operands: count: `u32`, site: `u64`
+        ///
+        /// Stack: count * (cooked_value, raw_value) **=>** template
+        TemplateCreate,
+
         /// No-operation instruction, does nothing.
         ///
         /// Operands: