Reduce environment allocations (#4002)

* Skip environment creation when all bindings in the scope are local

* Skip environment creation when possible for arrow functions

* Do not allocate space for local bindings in runtime environments

* Change RefCell to Cell

core/ast/src/expression/literal/object.rs

@@ -469,6 +469,13 @@ impl ObjectMethodDefinition {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the object method definition contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for ObjectMethodDefinition {

core/ast/src/function/arrow_function.rs

@@ -86,6 +86,13 @@ impl ArrowFunction {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the arrow function contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for ArrowFunction {

core/ast/src/function/async_arrow_function.rs

@@ -86,6 +86,13 @@ impl AsyncArrowFunction {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the function declaration contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for AsyncArrowFunction {

core/ast/src/function/async_function.rs

@@ -78,6 +78,13 @@ impl AsyncFunctionDeclaration {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the async function declaration contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for AsyncFunctionDeclaration {
@@ -207,6 +214,13 @@ impl AsyncFunctionExpression {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the async function expression contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for AsyncFunctionExpression {

core/ast/src/function/async_generator.rs

@@ -77,6 +77,13 @@ impl AsyncGeneratorDeclaration {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the async generator declaration contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for AsyncGeneratorDeclaration {
@@ -206,6 +213,13 @@ impl AsyncGeneratorExpression {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the async generator expression contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for AsyncGeneratorExpression {

core/ast/src/function/class.rs

@@ -748,6 +748,13 @@ impl ClassMethodDefinition {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the class method definition contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for ClassMethodDefinition {

core/ast/src/function/generator.rs

@@ -76,6 +76,13 @@ impl GeneratorDeclaration {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the generator declaration contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for GeneratorDeclaration {
@@ -205,6 +212,13 @@ impl GeneratorExpression {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the generator expression contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for GeneratorExpression {

core/ast/src/function/ordinary_function.rs

@@ -77,6 +77,13 @@ impl FunctionDeclaration {
     pub const fn scopes(&self) -> &FunctionScopes {
         &self.scopes
     }
+
+    /// Returns `true` if the function declaration contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
 }
 
 impl ToIndentedString for FunctionDeclaration {
@@ -207,6 +214,13 @@ impl FunctionExpression {
         &self.scopes
     }
 
+    /// Returns `true` if the function expression contains a direct call to `eval`.
+    #[inline]
+    #[must_use]
+    pub const fn contains_direct_eval(&self) -> bool {
+        self.contains_direct_eval
+    }
+
     /// Analyze the scope of the function expression.
     pub fn analyze_scope(&mut self, strict: bool, scope: &Scope, interner: &Interner) -> bool {
         if !collect_bindings(self, strict, false, scope, interner) {