[go-nuts] use delve to debug golang with 'next' will skip some step

[林 子鹏]

When I use delve to debug this project(dlv debug t.go):

//t.go
package main

import (
    "fmt"
    "os"
    "reflect"
    "unsafe"
)

func main() {
    s1 := make([]uint8, 0)
    aboutSlice(&s1, "s1")
    s2 := make([]uint8, 8)
    aboutSlice(&s2, "s2")
    new_s1 := append(s1, 10)
    new_s2 := append(s2, 20)
    aboutSlice(&new_s1, "new_s1")
    aboutSlice(&new_s2, "new_s2")
    os.Exit(0)
}

func aboutSlice(s *[]uint8, n string) {
    fmt.Printf("%s:\tmem_addr:%p\tsize:%v\taddr:%#x\tlen:%v\tcap:%v\n", n, s, unsafe.Sizeof(*s), (*reflect.SliceHeader)(unsafe.Pointer(s)).Data, len(*s), cap(*s))
}

I want to analyze the behavior of function growslice(in runtime/slice.go),and then set breakpoints on func growslice,I use n and s to analyze it, but it will skip some step, like the picture below:

[jake...@gmail.com]

Was the code built with optimizations disabled?

[drc...@google.com]

That debugging is (now) in the runtime package, which is (always) compiled with optimizations on.

That will tend to interfere with debugging.  The 1.17 change to use registers for passing parameters

has also caused some regressions in debugging quality (and it would be nice to fix those, but it is tricky).