在golang运行时源代码中，嵌套的延迟函数调用的recover接收到的panic与当前goroutine的panic不同，这是什么逻辑？

gorecover函数如何获取其argp参数？

这个答案只告诉我原理，Why recover() does not work in a nested deferred function?

• 但我想弄清楚golang运行时实现的细节。*

我的演示代码：

package main

import "fmt"

func main() {
    defer func() {
        fmt.Println("enter defer 1")
        defer func() {
            fmt.Println("enter defer 2")
            recover()
            // if e := recover(); e != nil {
            //  fmt.Println("recover")
            // }
            fmt.Println("exit defer 2")
        }()
        fmt.Println("exit defer 1")
    }()
    panic(404)
}

字符串
我的输出

➜  cmd git:(master) ✗ go run main.go                              
enter defer 1
exit defer 1
enter defer 2
exit defer 2
panic: 404

goroutine 1 [running]:
main.main()
        /Users/polar/code/leetcode/leetcode-go/demo/defer-demo/cmd2/main.go:18 +0x49
exit status 2

型
我尝试调试以在这段golang运行时源代码中获得更多信息：
golang运行时恢复函数的源代码。

// /Paht/to/go/src/runtime/panic.go
func gorecover(argp uintptr) any {
    // Must be in a function running as part of a deferred call during the panic.
    // Must be called from the topmost function of the call
    // (the function used in the defer statement).
    // p.argp is the argument pointer of that topmost deferred function call.
    // Compare against argp reported by caller.
    // If they match, the caller is the one who can recover.
    gp := getg()
    p := gp._panic
    if p != nil && !p.goexit && !p.recovered && argp == uintptr(p.argp) {
        p.recovered = true
        return p.arg
    }
    return nil
}

型
以下是我得到的：

gp._panic的值为

*runtime._panic 
{argp: unsafe.Pointer(0xc00007be58), 
arg: interface {}(int) 404, 
link: *runtime._panic nil, 
pc: 0, 
sp: unsafe.Pointer(0x0), 
recovered: false, 
aborted: false, 
goexit: false}

型

argp的值为

(unreadable could not find loclist entry at 0x2ffec for address 0x1036d0a)

型