From f084460e5a23b6c373aef2a8ff3737afe6785367 Mon Sep 17 00:00:00 2001
From: Haled Odat <8566042+HalidOdat@users.noreply.github.com>
Date: Sun, 29 Oct 2023 22:17:05 +0100
Subject: [PATCH] Move parameter environment creation to opcode

---
 boa_engine/src/bytecompiler/declarations.rs      |  9 +++------
 .../src/object/internal_methods/function.rs      | 16 ----------------
 boa_engine/src/vm/code_block.rs                  | 12 +-----------
 3 files changed, 4 insertions(+), 33 deletions(-)

diff --git a/boa_engine/src/bytecompiler/declarations.rs b/boa_engine/src/bytecompiler/declarations.rs
index 78551fc6ff0..3d3109b8dbb 100644
--- a/boa_engine/src/bytecompiler/declarations.rs
+++ b/boa_engine/src/bytecompiler/declarations.rs
@@ -4,10 +4,7 @@ use crate::{
     bytecompiler::{ByteCompiler, FunctionCompiler, FunctionSpec, NodeKind},
     environments::CompileTimeEnvironment,
     js_string,
-    vm::{
-        create_function_object_fast, create_generator_function_object, BindingOpcode,
-        CodeBlockFlags, Opcode,
-    },
+    vm::{create_function_object_fast, create_generator_function_object, BindingOpcode, Opcode},
     JsNativeError, JsResult,
 };
 use boa_ast::{
@@ -930,8 +927,8 @@ impl ByteCompiler<'_, '_> {
             // c. Let env be NewDeclarativeEnvironment(calleeEnv).
             // d. Assert: The VariableEnvironment of calleeContext is calleeEnv.
             // e. Set the LexicalEnvironment of calleeContext to env.
-            let _ = self.push_compile_environment(false);
-            self.code_block_flags |= CodeBlockFlags::PARAMETERS_ENV_BINDINGS;
+            let env_index = self.push_compile_environment(false);
+            self.emit_with_varying_operand(Opcode::PushDeclarativeEnvironment, env_index);
         };
 
         let env = self.lexical_environment.clone();
diff --git a/boa_engine/src/object/internal_methods/function.rs b/boa_engine/src/object/internal_methods/function.rs
index 91a76142c7e..d9139b6c14c 100644
--- a/boa_engine/src/object/internal_methods/function.rs
+++ b/boa_engine/src/object/internal_methods/function.rs
@@ -113,14 +113,6 @@ pub(crate) fn function_call(
         FunctionSlots::new(this, function_object.clone(), None),
     );
 
-    if code.has_parameters_env_bindings() {
-        last_env += 1;
-        context
-            .vm
-            .environments
-            .push_lexical(code.constant_compile_time_environment(last_env));
-    }
-
     Ok(CallValue::Ready)
 }
 
@@ -216,14 +208,6 @@ fn function_construct(
         ),
     );
 
-    if code.has_parameters_env_bindings() {
-        last_env += 1;
-        context
-            .vm
-            .environments
-            .push_lexical(code.constant_compile_time_environment(last_env));
-    }
-
     // Insert `this` value
     context
         .vm
diff --git a/boa_engine/src/vm/code_block.rs b/boa_engine/src/vm/code_block.rs
index 38b925b51ff..63cf7021689 100644
--- a/boa_engine/src/vm/code_block.rs
+++ b/boa_engine/src/vm/code_block.rs
@@ -58,11 +58,8 @@ bitflags! {
         /// The `[[IsClassConstructor]]` internal slot.
         const IS_CLASS_CONSTRUCTOR = 0b0000_0100;
 
-        /// Does this function have a parameters environment.
-        const PARAMETERS_ENV_BINDINGS = 0b0000_1000;
-
         /// The `[[ClassFieldInitializerName]]` internal slot.
-        const IN_CLASS_FIELD_INITIALIZER = 0b0010_0000;
+        const IN_CLASS_FIELD_INITIALIZER = 0b0000_1000;
 
         /// `[[ConstructorKind]]`
         const IS_DERIVED_CONSTRUCTOR = 0b0100_0000;
@@ -222,13 +219,6 @@ impl CodeBlock {
             .contains(CodeBlockFlags::HAS_BINDING_IDENTIFIER)
     }
 
-    /// Does this function have a parameters environment.
-    pub(crate) fn has_parameters_env_bindings(&self) -> bool {
-        self.flags
-            .get()
-            .contains(CodeBlockFlags::PARAMETERS_ENV_BINDINGS)
-    }
-
     /// Does this function have the `[[ClassFieldInitializerName]]` internal slot set to non-empty value.
     pub(crate) fn in_class_field_initializer(&self) -> bool {
         self.flags