Make environments opcodes use varying operands (#3340)

boa_engine/src/builtins/eval/mod.rs

@@ -232,16 +232,13 @@ impl Eval {
             context,
         );
 
-        compiler.push_compile_environment(strict);
-
-        let push_env = compiler.emit_opcode_with_operand(Opcode::PushDeclarativeEnvironment);
+        let env_index = compiler.push_compile_environment(strict);
+        compiler.emit_with_varying_operand(Opcode::PushDeclarativeEnvironment, env_index);
 
         compiler.eval_declaration_instantiation(&body, strict)?;
         compiler.compile_statement_list(body.statements(), true, false);
 
-        let env_index = compiler.pop_compile_environment();
-        compiler.patch_jump_with_target(push_env, env_index);
-
+        compiler.pop_compile_environment();
         compiler.emit_opcode(Opcode::PopEnvironment);
 
         let code_block = Gc::new(compiler.finish());

boa_engine/src/bytecompiler/class.rs

@@ -26,13 +26,14 @@ impl ByteCompiler<'_, '_> {
     pub(crate) fn compile_class(&mut self, class: &Class, expression: bool) {
         let class_name = class.name().map_or(Sym::EMPTY_STRING, Identifier::sym);
 
-        let class_env: Option<super::Label> = match class.name() {
+        let class_env = match class.name() {
             Some(name) if class.has_binding_identifier() => {
-                self.push_compile_environment(false);
+                let env_index = self.push_compile_environment(false);
                 self.create_immutable_binding(name, true);
-                Some(self.emit_opcode_with_operand(Opcode::PushDeclarativeEnvironment))
+                self.emit_with_varying_operand(Opcode::PushDeclarativeEnvironment, env_index);
+                true
             }
-            _ => None,
+            _ => false,
         };
 
         let mut compiler = ByteCompiler::new(
@@ -43,7 +44,8 @@ impl ByteCompiler<'_, '_> {
             self.context,
         );
 
-        compiler.push_compile_environment(true);
+        // Function environment
+        let _ = compiler.push_compile_environment(true);
 
         if let Some(expr) = class.constructor() {
             compiler.length = expr.parameters().length();
@@ -59,15 +61,11 @@ impl ByteCompiler<'_, '_> {
 
             compiler.compile_statement_list(expr.body().statements(), false, false);
 
-            let env_index = compiler.pop_compile_environment();
-
-            if let Some(env_label) = env_label {
-                compiler.patch_jump_with_target(env_label, env_index);
+            if env_label {
                 compiler.pop_compile_environment();
             } else {
                 compiler.code_block_flags |= CodeBlockFlags::IS_CLASS_CONSTRUCTOR;
             }
-
             compiler.emit_opcode(Opcode::PushUndefined);
         } else {
             if class.super_ref().is_some() {
@@ -76,10 +74,10 @@ impl ByteCompiler<'_, '_> {
                 compiler.emit_opcode(Opcode::RestParameterPop);
                 compiler.emit_opcode(Opcode::PushUndefined);
             }
-            compiler.pop_compile_environment();
             compiler.code_block_flags |= CodeBlockFlags::IS_CLASS_CONSTRUCTOR;
         }
         compiler.emit_opcode(Opcode::SetReturnValue);
+        compiler.pop_compile_environment();
 
         let code = Gc::new(compiler.finish());
         let index = self.functions.len() as u32;
@@ -119,7 +117,7 @@ impl ByteCompiler<'_, '_> {
         let mut static_elements = Vec::new();
         let mut static_field_name_count = 0;
 
-        if class_env.is_some() {
+        if class_env {
             self.emit_opcode(Opcode::Dup);
             self.emit_binding(BindingOpcode::InitConst, class_name.into());
         }
@@ -282,7 +280,9 @@ impl ByteCompiler<'_, '_> {
                         self.current_environment.clone(),
                         self.context,
                     );
-                    field_compiler.push_compile_environment(true);
+
+                    // Function environment
+                    let _ = field_compiler.push_compile_environment(true);
                     if let Some(node) = field {
                         field_compiler.compile_expr(node, true);
                     } else {
@@ -314,7 +314,7 @@ impl ByteCompiler<'_, '_> {
                         self.current_environment.clone(),
                         self.context,
                     );
-                    field_compiler.push_compile_environment(true);
+                    let _ = field_compiler.push_compile_environment(true);
                     if let Some(node) = field {
                         field_compiler.compile_expr(node, true);
                     } else {
@@ -358,7 +358,7 @@ impl ByteCompiler<'_, '_> {
                         self.current_environment.clone(),
                         self.context,
                     );
-                    field_compiler.push_compile_environment(true);
+                    let _ = field_compiler.push_compile_environment(true);
                     if let Some(node) = field {
                         field_compiler.compile_expr(node, true);
                     } else {
@@ -393,7 +393,7 @@ impl ByteCompiler<'_, '_> {
                         self.current_environment.clone(),
                         self.context,
                     );
-                    compiler.push_compile_environment(true);
+                    let _ = compiler.push_compile_environment(true);
 
                     compiler.function_declaration_instantiation(
                         body,
@@ -589,9 +589,8 @@ impl ByteCompiler<'_, '_> {
         self.emit_opcode(Opcode::Swap);
         self.emit_opcode(Opcode::Pop);
 
-        if let Some(class_env) = class_env {
-            let env_index = self.pop_compile_environment();
-            self.patch_jump_with_target(class_env, env_index);
+        if class_env {
+            self.pop_compile_environment();
             self.emit_opcode(Opcode::PopEnvironment);
         }
 

boa_engine/src/bytecompiler/declarations.rs

@@ -1,5 +1,5 @@
 use crate::{
-    bytecompiler::{ByteCompiler, FunctionCompiler, FunctionSpec, Label, NodeKind},
+    bytecompiler::{ByteCompiler, FunctionCompiler, FunctionSpec, NodeKind},
     environments::BindingLocatorError,
     vm::{
         create_function_object_fast, create_generator_function_object, BindingOpcode,
@@ -809,8 +809,8 @@ impl ByteCompiler<'_, '_> {
         arrow: bool,
         strict: bool,
         generator: bool,
-    ) -> (Option<Label>, bool) {
-        let mut env_label = None;
+    ) -> (bool, bool) {
+        let mut env_label = false;
         let mut additional_env = false;
 
         // 1. Let calleeContext be the running execution context.
@@ -910,7 +910,7 @@ impl ByteCompiler<'_, '_> {
             // c. Let env be NewDeclarativeEnvironment(calleeEnv).
             // d. Assert: The VariableEnvironment of calleeContext is calleeEnv.
             // e. Set the LexicalEnvironment of calleeContext to env.
-            self.push_compile_environment(false);
+            let _ = self.push_compile_environment(false);
             additional_env = true;
         }
 
@@ -1030,8 +1030,9 @@ impl ByteCompiler<'_, '_> {
             //          visibility of declarations in the function body.
             // b. Let varEnv be NewDeclarativeEnvironment(env).
             // c. Set the VariableEnvironment of calleeContext to varEnv.
-            self.push_compile_environment(false);
-            env_label = Some(self.emit_opcode_with_operand(Opcode::PushDeclarativeEnvironment));
+            let env_index = self.push_compile_environment(false);
+            self.emit_with_varying_operand(Opcode::PushDeclarativeEnvironment, env_index);
+            env_label = true;
 
             // d. Let instantiatedVarNames be a new empty List.
             let mut instantiated_var_names = Vec::new();

boa_engine/src/bytecompiler/env.rs

@@ -6,29 +6,32 @@ use boa_ast::expression::Identifier;
 
 impl ByteCompiler<'_, '_> {
     /// Push either a new declarative or function environment on the compile time environment stack.
-    pub(crate) fn push_compile_environment(&mut self, function_scope: bool) {
+    #[must_use]
+    pub(crate) fn push_compile_environment(&mut self, function_scope: bool) -> u32 {
         self.current_open_environments_count += 1;
+
         self.current_environment = Rc::new(CompileTimeEnvironment::new(
             self.current_environment.clone(),
             function_scope,
         ));
+
+        let index = self.compile_environments.len() as u32;
+        self.compile_environments
+            .push(self.current_environment.clone());
+
+        index
     }
 
     /// Pops the top compile time environment and returns its index in the compile time environments array.
     #[track_caller]
-    pub(crate) fn pop_compile_environment(&mut self) -> u32 {
+    pub(crate) fn pop_compile_environment(&mut self) {
         self.current_open_environments_count -= 1;
-        let index = self.compile_environments.len() as u32;
-        self.compile_environments
-            .push(self.current_environment.clone());
 
         let outer = self
             .current_environment
             .outer()
             .expect("cannot pop the global environment");
         self.current_environment = outer;
-
-        index
     }
 
     /// Get the binding locator of the binding at bytecode compile time.

boa_engine/src/bytecompiler/function.rs

@@ -100,12 +100,12 @@ impl FunctionCompiler {
 
         if let Some(binding_identifier) = self.binding_identifier {
             compiler.code_block_flags |= CodeBlockFlags::HAS_BINDING_IDENTIFIER;
-            compiler.push_compile_environment(false);
+            let _ = compiler.push_compile_environment(false);
             compiler.create_immutable_binding(binding_identifier.into(), self.strict);
         }
 
         // Function environment
-        compiler.push_compile_environment(true);
+        let _ = compiler.push_compile_environment(true);
 
         // Taken from:
         //  - 15.9.3 Runtime Semantics: EvaluateAsyncConciseBody: <https://tc39.es/ecma262/#sec-runtime-semantics-evaluateasyncconcisebody>
@@ -155,9 +155,8 @@ impl FunctionCompiler {
 
         compiler.compile_statement_list(body.statements(), false, false);
 
-        if let Some(env_labels) = env_label {
-            let env_index = compiler.pop_compile_environment();
-            compiler.patch_jump_with_target(env_labels, env_index);
+        if env_label {
+            compiler.pop_compile_environment();
         }
 
         if additional_env {

boa_engine/src/bytecompiler/statement/block.rs

@@ -4,15 +4,13 @@ use boa_ast::statement::Block;
 impl ByteCompiler<'_, '_> {
     /// Compile a [`Block`] `boa_ast` node
     pub(crate) fn compile_block(&mut self, block: &Block, use_expr: bool) {
-        self.push_compile_environment(false);
-        let push_env = self.emit_opcode_with_operand(Opcode::PushDeclarativeEnvironment);
+        let env_index = self.push_compile_environment(false);
+        self.emit_with_varying_operand(Opcode::PushDeclarativeEnvironment, env_index);
 
         self.block_declaration_instantiation(block);
         self.compile_statement_list(block.statement_list(), use_expr, true);
 
-        let env_index = self.pop_compile_environment();
-        self.patch_jump_with_target(push_env, env_index);
-
+        self.pop_compile_environment();
         self.emit_opcode(Opcode::PopEnvironment);
     }
 }