package main

import "fmt"

// dlv 断点调试法
/*

下载安装：
    go get -u github.com/derekparker/delve/cmd/dlv

使用： 
(base) ➜  dlv dlv debug ./learn2.go
Type 'help' for list of commands.
(dlv) help
The following commands are available:
    args ------------------------ Print function arguments.
    break (alias: b) ------------ Sets a breakpoint.
    breakpoints (alias: bp) ----- Print out info for active breakpoints.
    call ------------------------ Resumes process, injecting a function call (EXPERIMENTAL!!!)
    clear ----------------------- Deletes breakpoint.
    clearall -------------------- Deletes multiple breakpoints.
    condition (alias: cond) ----- Set breakpoint condition.
    config ---------------------- Changes configuration parameters.
    continue (alias: c) --------- Run until breakpoint or program termination.
    deferred -------------------- Executes command in the context of a deferred call.
    disassemble (alias: disass) - Disassembler.
    down ------------------------ Move the current frame down.
    edit (alias: ed) ------------ Open where you are in $DELVE_EDITOR or $EDITOR
    exit (alias: quit | q) ------ Exit the debugger.
    frame ----------------------- Set the current frame, or execute command on a different frame.
    funcs ----------------------- Print list of functions.
    goroutine (alias: gr) ------- Shows or changes current goroutine
    goroutines (alias: grs) ----- List program goroutines.
    help (alias: h) ------------- Prints the help message.
    libraries ------------------- List loaded dynamic libraries
    list (alias: ls | l) -------- Show source code.
    locals ---------------------- Print local variables.
    next (alias: n) ------------- Step over to next source line.
    on -------------------------- Executes a command when a breakpoint is hit.
    print (alias: p) ------------ Evaluate an expression.
    regs ------------------------ Print contents of CPU registers.
    restart (alias: r) ---------- Restart process.
    set ------------------------- Changes the value of a variable.
    source ---------------------- Executes a file containing a list of delve commands
    sources --------------------- Print list of source files.
    stack (alias: bt) ----------- Print stack trace.
    step (alias: s) ------------- Single step through program.
    step-instruction (alias: si)  Single step a single cpu instruction.
    stepout --------------------- Step out of the current function.
    thread (alias: tr) ---------- Switch to the specified thread.
    threads --------------------- Print out info for every traced thread.
    trace (alias: t) ------------ Set tracepoint.
    types ----------------------- Print list of types
    up -------------------------- Move the current frame up.
    vars ------------------------ Print package variables.
    whatis ---------------------- Prints type of an expression.
    Type help followed by a command for full documentation.

    以上为全部命令， 常用的有一下几个：
    b 打断点
    eg:
        b main.main  或者使用文件:行号来打断点
    p 打印：
    eg:
        p a   打印a变量
    n: 执行到下一行
    c: 跳过此断点
    args: 打印所有的方法参数
    locals  打印出所有的本地变量
    l 列出断点最近几行的代码
    bp: 展示出所有的断点
    q: 退出
*/

func main() {
    a := []string{"a", "b", "c", "D", "ef"}
    for k, v := range a {
        fmt.Println(k, v)
    }
}

使用示例

(base) ➜  dlv dlv debug ./learn2.go
Type 'help' for list of commands.
(dlv) b main.main
Breakpoint 1 set at 0x4a243b for main.main() ./learn2.go:67
(dlv) c
> main.main() ./learn2.go:67 (hits goroutine(1):1 total:1) (PC: 0x4a243b)
    62:     c: 跳过此断点
    63:     args: 打印所有的方法参数
    64:     locals  打印出所有的本地变量
    65: */
    66: 
=>  67: func main() {
    68:     a := []string{"a", "b", "c", "D", "ef"}
    69:     for k, v := range a {
    70:         fmt.Println(k, v)
    71:     }
    72: }
(dlv) l
> main.main() ./learn2.go:67 (hits goroutine(1):1 total:1) (PC: 0x4a243b)
    62:     c: 跳过此断点
    63:     args: 打印所有的方法参数
    64:     locals  打印出所有的本地变量
    65: */
    66: 
=>  67: func main() {
    68:     a := []string{"a", "b", "c", "D", "ef"}
    69:     for k, v := range a {
    70:         fmt.Println(k, v)
    71:     }
    72: }
(dlv) b 70
Breakpoint 2 set at 0x4a253c for main.main() ./learn2.go:70
(dlv) bp 
Breakpoint runtime-fatal-throw at 0x42c4a0 for runtime.fatalthrow() /home/yz/go/src/runtime/panic.go:663 (0)
Breakpoint unrecovered-panic at 0x42c510 for runtime.fatalpanic() /home/yz/go/src/runtime/panic.go:690 (0)
    print runtime.curg._panic.arg
Breakpoint 1 at 0x4a243b for main.main() ./learn2.go:67 (1)
Breakpoint 2 at 0x4a253c for main.main() ./learn2.go:70 (0)
(dlv) c
> main.main() ./learn2.go:70 (hits goroutine(1):1 total:1) (PC: 0x4a253c)
Warning: listing may not match stale executable
    65:     l 列出断点最近几行的代码
    66:     bp: 展示出所有的断点
    67: 
    68: 
    69: */
=>  70: 
    71: func main() {
    72:     a := []string{"a", "b", "c", "D", "ef"}
    73:     for k, v := range a {
    74:         fmt.Println(k, v)
    75:     }
(dlv) p k
0
(dlv) p v
"a"
(dlv) n 
0 a
> main.main() ./learn2.go:69 (PC: 0x4a261b)
Warning: listing may not match stale executable
    64:     locals  打印出所有的本地变量
    65:     l 列出断点最近几行的代码
    66:     bp: 展示出所有的断点
    67: 
    68: 
=>  69: */
    70: 
    71: func main() {
    72:     a := []string{"a", "b", "c", "D", "ef"}
    73:     for k, v := range a {
    74:         fmt.Println(k, v)
(dlv) p k
0
(dlv) n
> main.main() ./learn2.go:70 (hits goroutine(1):2 total:2) (PC: 0x4a253c)
Warning: listing may not match stale executable
    65:     l 列出断点最近几行的代码
    66:     bp: 展示出所有的断点
    67: 
    68: 
    69: */
=>  70: 
    71: func main() {
    72:     a := []string{"a", "b", "c", "D", "ef"}
    73:     for k, v := range a {
    74:         fmt.Println(k, v)
    75:     }
(dlv) n
1 b
> main.main() ./learn2.go:69 (PC: 0x4a261b)
Warning: listing may not match stale executable
    64:     locals  打印出所有的本地变量
    65:     l 列出断点最近几行的代码
    66:     bp: 展示出所有的断点
    67: 
    68: 
=>  69: */
    70: 
    71: func main() {
    72:     a := []string{"a", "b", "c", "D", "ef"}
    73:     for k, v := range a {
    74:         fmt.Println(k, v)
(dlv) p k
1
(dlv) p v
"b"
(dlv) c
> main.main() ./learn2.go:70 (hits goroutine(1):3 total:3) (PC: 0x4a253c)
Warning: listing may not match stale executable
    65:     l 列出断点最近几行的代码
    66:     bp: 展示出所有的断点
    67: 
    68: 
    69: */
=>  70: 
    71: func main() {
    72:     a := []string{"a", "b", "c", "D", "ef"}
    73:     for k, v := range a {
    74:         fmt.Println(k, v)
    75:     }
(dlv) c
2 c
> main.main() ./learn2.go:70 (hits goroutine(1):4 total:4) (PC: 0x4a253c)
Warning: listing may not match stale executable
    65:     l 列出断点最近几行的代码
    66:     bp: 展示出所有的断点
    67: 
    68: 
    69: */
=>  70: 
    71: func main() {
    72:     a := []string{"a", "b", "c", "D", "ef"}
    73:     for k, v := range a {
    74:         fmt.Println(k, v)
    75:     }
(dlv) c
3 D
> main.main() ./learn2.go:70 (hits goroutine(1):5 total:5) (PC: 0x4a253c)
Warning: listing may not match stale executable
    65:     l 列出断点最近几行的代码
    66:     bp: 展示出所有的断点
    67: 
    68: 
    69: */
=>  70: 
    71: func main() {
    72:     a := []string{"a", "b", "c", "D", "ef"}
    73:     for k, v := range a {
    74:         fmt.Println(k, v)
    75:     }
(dlv) c
4 ef
Process 16382 has exited with status 0
(dlv) q
Process 16382 has exited with status 0