From 922f69e5e2e82394bc6e82400d37d7873f4b7042 Mon Sep 17 00:00:00 2001
From: "Jeong, YunWon" <jeong@youknowone.org>
Date: Sun, 18 Jan 2026 20:48:02 +0900
Subject: [PATCH] sys._jit

---
 Lib/test/support/__init__.py |  4 +---
 crates/vm/src/stdlib/sys.rs  | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index e221ee0463..cc5a48738f 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -2783,9 +2783,7 @@ def exceeds_recursion_limit():
 
 Py_TRACE_REFS = hasattr(sys, 'getobjects')
 
-# XXX: RUSTPYTHON; we don't have sys._jit yet
-# _JIT_ENABLED = sys._jit.is_enabled()
-_JIT_ENABLED = False
+_JIT_ENABLED = sys._jit.is_enabled()
 requires_jit_enabled = unittest.skipUnless(_JIT_ENABLED, "requires JIT enabled")
 requires_jit_disabled = unittest.skipIf(_JIT_ENABLED, "requires JIT disabled")
 
diff --git a/crates/vm/src/stdlib/sys.rs b/crates/vm/src/stdlib/sys.rs
index 4917e3e43c..5446b04c6d 100644
--- a/crates/vm/src/stdlib/sys.rs
+++ b/crates/vm/src/stdlib/sys.rs
@@ -4,6 +4,30 @@ pub(crate) use sys::{
     __module_def, DOC, MAXSIZE, RUST_MULTIARCH, UnraisableHookArgsData, multiarch,
 };
 
+#[pymodule(name = "_jit")]
+mod sys_jit {
+    /// Return True if the current Python executable supports JIT compilation,
+    /// and False otherwise.
+    #[pyfunction]
+    const fn is_available() -> bool {
+        false // RustPython has no JIT
+    }
+
+    /// Return True if JIT compilation is enabled for the current Python process,
+    /// and False otherwise.
+    #[pyfunction]
+    const fn is_enabled() -> bool {
+        false // RustPython has no JIT
+    }
+
+    /// Return True if the topmost Python frame is currently executing JIT code,
+    /// and False otherwise.
+    #[pyfunction]
+    const fn is_active() -> bool {
+        false // RustPython has no JIT
+    }
+}
+
 #[pymodule]
 mod sys {
     use crate::{
@@ -1554,9 +1578,14 @@ pub(crate) fn init_module(vm: &VirtualMachine, module: &Py<PyModule>, builtins:
     modules
         .set_item("builtins", builtins.to_owned().into(), vm)
         .unwrap();
+
+    // Create sys._jit submodule
+    let jit_module = sys_jit::make_module(vm);
+
     extend_module!(vm, module, {
         "__doc__" => sys::DOC.to_owned().to_pyobject(vm),
         "modules" => modules,
+        "_jit" => jit_module,
     });
 }