LibJS: Add BytecodeGenerator helpers for reference get/put

This allows code sharing between all AST nodes that want to get and/or
put through a reference.

Userland/Libraries/LibJS/Bytecode/Generator.cpp

@@ -93,4 +93,65 @@ void Generator::end_breakable_scope()
 {
  m_breakable_scopes.take_last();
 }
+
+void Generator::emit_load_from_reference(JS::ASTNode const& node)
+{
+ if (is<Identifier>(node)) {
+ auto& identifier = static_cast<Identifier const&>(node);
+ emit<Bytecode::Op::GetVariable>(intern_identifier(identifier.string()));
+ return;
+ }
+ if (is<MemberExpression>(node)) {
+ auto& expression = static_cast<MemberExpression const&>(node);
+ expression.object().generate_bytecode(*this);
+
+ auto object_reg = allocate_register();
+ emit<Bytecode::Op::Store>(object_reg);
+
+ if (expression.is_computed()) {
+ expression.property().generate_bytecode(*this);
+ emit<Bytecode::Op::GetByValue>(object_reg);
+ } else {
+ auto identifier_table_ref = intern_identifier(verify_cast<Identifier>(expression.property()).string());
+ emit<Bytecode::Op::GetById>(identifier_table_ref);
+ }
+ return;
+ }
+ VERIFY_NOT_REACHED();
+}
+
+void Generator::emit_store_to_reference(JS::ASTNode const& node)
+{
+ if (is<Identifier>(node)) {
+ auto& identifier = static_cast<Identifier const&>(node);
+ emit<Bytecode::Op::SetVariable>(intern_identifier(identifier.string()));
+ return;
+ }
+ if (is<MemberExpression>(node)) {
+ // NOTE: The value is in the accumulator, so we have to store that away first.
+ auto value_reg = allocate_register();
+ emit<Bytecode::Op::Store>(value_reg);
+
+ auto& expression = static_cast<MemberExpression const&>(node);
+ expression.object().generate_bytecode(*this);
+
+ auto object_reg = allocate_register();
+ emit<Bytecode::Op::Store>(object_reg);
+
+ if (expression.is_computed()) {
+ expression.property().generate_bytecode(*this);
+ auto property_reg = allocate_register();
+ emit<Bytecode::Op::Store>(property_reg);
+ emit<Bytecode::Op::Load>(value_reg);
+ emit<Bytecode::Op::PutByValue>(object_reg, property_reg);
+ } else {
+ emit<Bytecode::Op::Load>(value_reg);
+ auto identifier_table_ref = intern_identifier(verify_cast<Identifier>(expression.property()).string());
+ emit<Bytecode::Op::PutById>(object_reg, identifier_table_ref);
+ }
+ return;
+ }
+ VERIFY_NOT_REACHED();
+}
+
 }

Userland/Libraries/LibJS/Bytecode/Generator.h

@@ -70,6 +70,9 @@ class Generator {
  return *static_cast<OpType*>(slot);
  }
 
+ void emit_load_from_reference(JS::ASTNode const&);
+ void emit_store_to_reference(JS::ASTNode const&);
+
  void begin_continuable_scope(Label continue_target);
  void end_continuable_scope();
  void begin_breakable_scope(Label breakable_target);