JIT trace not invalidated after re-linking
还没有人认领这个 Issue。
- 主要语言
- C
- 星标
- 40.4k
- 派生
- 8.1k
- 平均合并
- 2 天 13 小时
- 30 天内合并 PR
- 96
描述
Description
JIT traces are not invalidated after a class is re-linked. The JIT code may make assumptions that are not true anymore after re-linking.
For example, in
<?php
$a=0;
class A implement Iface {
public function hello() {
global $a;
for ($i = 0; $i < 100; $i++) {
$a++;
}
}
}
we may still enter in the JITed loop after A has been re-linked (A can be re-link due to Iface being recompiled for example). The JITed code may be based on assumptions that are not true anymore (at least the run_time_cache pointer changes during linking, but I suspect that other assumptions can be made based on the parent classes or interfaces, that do not hold true after re-linking).
This is due to op_array.oplines being shared between all linked versions of the same class. oplines has pointers to JITed code.
op_array.oplines is also shared between all sub-classes, but as long as the JIT's asumptions are based on the declaring class it should be ok.
PHP Version
PHP 8.1
Operating System
No response
贡献指南
从这里开始
- 先读完整个 Issue,再读项目的贡献指南。
- 在 Issue 下留言说明你要接手 —— 这能避免两个人做同样的事。
- Fork 仓库,在一个分支上完成修改。
- 提交 Pull Request,并在描述里引用这个 Issue 编号。
调研方向
未指定源文件或测试。从 PHP 8.1 示例开始,调查类重新链接过程中的 JIT 跟踪;完成标准是使过时的 JIT 代码失效,从而执行不能保留此前已链接类的假设,并为该场景提供回归覆盖。
由索引模型根据 Issue 内容生成。
评估
- 技术栈
- c, php
- 领域
- compilers
- Issue 类型
- 缺陷
- 难度
- 4/5
- 预计耗时
- 3-5 天
- 活跃度
- 停滞
- 描述清晰度
- 需要澄清
- 新手友好度
- 35/100