LibJS/JIT: Compile the Append instruction

Userland/Libraries/LibJS/Bytecode/Op.h

@@ -318,6 +318,9 @@ public:
     ThrowCompletionOr<void> execute_impl(Bytecode::Interpreter&) const;
     DeprecatedString to_deprecated_string_impl(Bytecode::Executable const&) const;
 
+    Register lhs() const { return m_lhs; }
+    bool is_spread() const { return m_is_spread; }
+
 private:
     Register m_lhs;
     bool m_is_spread = false;

Userland/Libraries/LibJS/JIT/Compiler.cpp

@@ -1319,6 +1319,23 @@ void Compiler::compile_iterator_to_array(Bytecode::Op::IteratorToArray const&)
     check_exception();
 }
 
+static Value cxx_append(VM& vm, Value lhs, Value rhs, bool is_spread)
+{
+    TRY_OR_SET_EXCEPTION(Bytecode::append(vm, lhs, rhs, is_spread));
+    return {};
+}
+
+void Compiler::compile_append(Bytecode::Op::Append const& op)
+{
+    load_vm_register(ARG1, op.lhs());
+    load_vm_register(ARG2, Bytecode::Register::accumulator());
+    m_assembler.mov(
+        Assembler::Operand::Register(ARG3),
+        Assembler::Operand::Imm(static_cast<u64>(op.is_spread())));
+    native_call((void*)cxx_append);
+    check_exception();
+}
+
 void Compiler::jump_to_exit()
 {
     m_assembler.jump(m_exit_label);

Userland/Libraries/LibJS/JIT/Compiler.h

@@ -113,7 +113,8 @@ private:
         O(ThrowIfNullish, throw_if_nullish)                                      \
         O(IteratorResultValue, iterator_result_value)                            \
         O(IteratorClose, iterator_close)                                         \
-        O(IteratorToArray, iterator_to_array)
+        O(IteratorToArray, iterator_to_array)                                    \
+        O(Append, append)
 
 #    define DECLARE_COMPILE_OP(OpTitleCase, op_snake_case) \
         void compile_##op_snake_case(Bytecode::Op::OpTitleCase const&);