go 调试器
go 没有官方的调式器，有个第三方调试工具delve在社区非常受欢迎。
安装delve
安装到GOBIN目录
$ go get -u github.com/go-delve/delve/cmd/dlv
将GOBIN目录添加到PATH环境变量中。
$ dlv version
Delve Debugger
Version: 1.3.0
Build: $Id: 2f59bfc686d60989dcef9de40b480d0a34aa2fa5
ok,安装成功。
delve使用
我先写一下要被调试的程序。
package main
import (
"fmt"
"time"
)
func test(a int) int {
d :=3
a = d+3
return a
}
func main() {
a ,b:=1,3
for i:=0;i<5;i++ {
a++
}
test(a)
go func() {
a +=1
b -=1
time.Sleep(10e9)
b +=1
}()
fmt.Println(a,b)
time.Sleep(100e9)
}
dlv debug 调试源码
用到main package目录下运行
$ dlv debug
Type 'help' for list of commands.
(dlv) h
The following commands are available:
args ------------------------ Print function arguments.
... //这边省略
Type help followed by a command for full documentation.
我们看了下使用帮助
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 (alias: so) --------- 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.
这个使用帮助的文档英文都不需要翻译，相信大家都能看懂。
你不需要死级记得上面的命令，进入dlv调试模式后，敲你命令搜字母 tab 一下就可以自动补全。实在忘记了，你再 help 一下就会显示帮助文档。
打断点
delve 打断点的命令是break 简写b，打断点有两种方式
- 我们知道某个包的某个函数比如
main.main我们使用break main.main就可以设置断点 - 我们知道某个源码文件第几行，我们可以用
break 文件名:行号的方式设置断点,例如break main.go:7
使用breakpoints可以查看所用设置的断点
$ dlv debug
Type 'help' for list of commands.
(dlv) break main.main
Breakpoint 1 set at 0x4aa148 for main.main() ./main.go:5
(dlv) b main.go:7
Breakpoint 2 set at 0x4aa1ab for main.main() ./main.go:7
(dlv) breakpoints
Breakpoint runtime-fatal-throw at 0x42ddc0 for runtime.fatalthrow() /home/wida/go/src/runtime/panic.go:820 (0)
Breakpoint unrecovered-panic at 0x42de30 for runtime.fatalpanic() /home/wida/go/src/runtime/panic.go:847 (0)
print runtime.curg._panic.arg
Breakpoint 1 at 0x4aa148 for main.main() ./main.go:5 (0)
Breakpoint 2 at 0x4aa1ab for main.main() ./main.go:7 (0)
(dlv)
设置好断点后我们可以使用 continue 让程序运行到断点。多个断点的话，再按continue就能到下一个断点。
(dlv) c
> main.main() ./main.go:12 (hits goroutine(1):1 total:1) (PC: 0x4aa3f8)
7: func test(a int) int {
8: d :=3
9: a = d+3
10: return a
11: }
=> 12: func main() {
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
15: a++
16: }
17: test(a)
(dlv) c
> main.main() ./main.go:15 (hits goroutine(1):1 total:1) (PC: 0x4aa476)
10: return a
11: }
12: func main() {
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
=> 15: a++
16: }
17: test(a)
18: go func() {
19: a +=1
20: b -=1
(dlv)
删除断点
clear 和 clearall 删除断点，clear命令后面有个参数 breakId
(dlv) breakpoints
Breakpoint runtime-fatal-throw at 0x42ddc0 for runtime.fatalthrow() /home/wida/go/src/runtime/panic.go:820 (0)
Breakpoint unrecovered-panic at 0x42de30 for runtime.fatalpanic() /home/wida/go/src/runtime/panic.go:847 (0)
print runtime.curg._panic.arg
Breakpoint 1 at 0x4aa3f8 for main.main() ./main.go:12 (1)
Breakpoint 2 at 0x4aa476 for main.main() ./main.go:15 (1)
cond i == 3
(dlv) clear 1
(dlv) breakpoints
Breakpoint runtime-fatal-throw at 0x42ddc0 for runtime.fatalthrow() /home/wida/go/src/runtime/panic.go:820 (0)
Breakpoint unrecovered-panic at 0x42de30 for runtime.fatalpanic() /home/wida/go/src/runtime/panic.go:847 (0)
print runtime.curg._panic.arg
Breakpoint 2 at 0x4aa476 for main.main() ./main.go:15 (1)
cond i == 3
(dlv) clearall
Breakpoint 2 cleared at 0x4aa476 for main.main() ./main.go:15
(dlv) breakpoints
Breakpoint runtime-fatal-throw at 0x42ddc0 for runtime.fatalthrow() /home/wida/go/src/runtime/panic.go:820 (0)
Breakpoint unrecovered-panic at 0x42de30 for runtime.fatalpanic() /home/wida/go/src/runtime/panic.go:847 (0)
print runtime.curg._panic.arg
断点上附加条件
condition 命令可以已有的断点上加上命令，有连个参数 condition breakId condition 第一个参数是已有断点的id（用breakpoints 可以知道），第二个是附加条件。
(dlv) breakpoints
Breakpoint runtime-fatal-throw at 0x42ddc0 for runtime.fatalthrow() /home/wida/go/src/runtime/panic.go:820 (0)
Breakpoint unrecovered-panic at 0x42de30 for runtime.fatalpanic() /home/wida/go/src/runtime/panic.go:847 (0)
print runtime.curg._panic.arg
Breakpoint 1 at 0x4aa3f8 for main.main() ./main.go:12 (0)
Breakpoint 2 at 0x4aa476 for main.main() ./main.go:15 (0)
(dlv) condition 2 i==3
(dlv) c
> main.main() ./main.go:12 (hits goroutine(1):1 total:1) (PC: 0x4aa3f8)
7: func test(a int) int {
8: d :=3
9: a = d+3
10: return a
11: }
=> 12: func main() {
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
15: a++
16: }
17: test(a)
(dlv) c
> main.main() ./main.go:15 (hits goroutine(1):1 total:1) (PC: 0x4aa476)
10: return a
11: }
12: func main() {
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
=> 15: a++
16: }
17: test(a)
18: go func() {
19: a +=1
20: b -=1
(dlv) locals
b = 3
a = 4
i = 3 //condition 命令已经生效
打印变量
locals打印局部变量vars打印所有包变量vars 包名打印包变量print打印变量值
(dlv) c
> main.main() ./main.go:17 (hits goroutine(1):1 total:1) (PC: 0x4aa4a0)
12: func main() {
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
15: a++
16: }
=> 17: test(a)
18: go func() {
19: a +=1
20: b -=1
21: time.Sleep(10e9)
22: b +=1
(dlv) locals
b = 3
a = 6
(dlv) print a
6
(dlv) print &a
(*int)(0xc0000ac010)
(dlv) print b
3
(dlv)
单步执行
next单步执行（遇到子函数不进入，只执行本文件下一行代码）step单步进入执行（遇到子函数会进入子函数）。stepout退出（执行完）当前函数到该函数被调用的下一行代码。
这边需要注意 next和step的区别
(dlv) b main.go:17
Breakpoint 1 set at 0x4aa4a0 for main.main() ./main.go:17
(dlv) c
> main.main() ./main.go:17 (hits goroutine(1):1 total:1) (PC: 0x4aa4a0)
12: func main() {
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
15: a++
16: }
=> 17: test(a)
18: go func() {
19: a +=1
20: b -=1
21: time.Sleep(10e9)
22: b +=1
(dlv) n
> main.main() ./main.go:18 (PC: 0x4aa4b9)
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
15: a++
16: }
17: test(a)
=> 18: go func() {
19: a +=1
20: b -=1
21: time.Sleep(10e9)
22: b +=1
23: }()
(dlv) r
Process restarted with PID 706
(dlv) c
> main.main() ./main.go:17 (hits goroutine(1):1 total:1) (PC: 0x4aa4a0)
12: func main() {
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
15: a++
16: }
=> 17: test(a)
18: go func() {
19: a +=1
20: b -=1
21: time.Sleep(10e9)
22: b +=1
(dlv) s
> main.test() ./main.go:7 (PC: 0x4aa3a0)
2:
3: import (
4: "fmt"
5: "time"
6: )
=> 7: func test(a int) int {
8: d :=3
9: a = d+3
10: return a
11: }
12: func main() {
(dlv) n
> main.test() ./main.go:8 (PC: 0x4aa3b7)
3: import (
4: "fmt"
5: "time"
6: )
7: func test(a int) int {
=> 8: d :=3
9: a = d+3
10: return a
11: }
12: func main() {
13: a ,b:=1,3
(dlv) so
> main.main() ./main.go:18 (PC: 0x4aa4b9)
Values returned:
~r1: 6
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
15: a++
16: }
17: test(a)
=> 18: go func() {
19: a +=1
20: b -=1
21: time.Sleep(10e9)
22: b +=1
23: }()
(dlv)
goroutine 切换
我们在调试的时候不能同事看到所有goroutine的情况，默认我们追踪的代码是在main goroutine中，我们有时候想看看非main goroutine的情况，就需要goroutine 切换的命令。
goroutines打印所有的goroutinegoroutine切换指定id的goroutine执行
Breakpoint 1 cleared at 0x4aa4a0 for main.main() ./main.go:17
(dlv) b main.go:18
(dlv) c
> main.main() ./main.go:18 (hits goroutine(1):1 total:1) (PC: 0x4aa4b9)
13: a ,b:=1,3
14: for i:=0;i<5;i++ {
15: a++
16: }
17: test(a)
=> 18: go func() {
19: a +=1
20: b -=1
21: time.Sleep(10e9)
22: b +=1
23: }()
(dlv) n
> main.main() ./main.go:24 (PC: 0x4aa4f7)
19: a +=1
20: b -=1
21: time.Sleep(10e9)
22: b +=1
23: }()
=> 24: fmt.Println(a,b)
25: time.Sleep(100e9)
26: }
(dlv) goroutines
* Goroutine 1 - User: ./main.go:24 main.main (0x4aa4f7) (thread 1903)
Goroutine 2 - User: /home/wida/go/src/runtime/proc.go:305 runtime.gopark (0x42faab)
Goroutine 3 - User: /home/wida/go/src/runtime/proc.go:305 runtime.gopark (0x42faab)
Goroutine 4 - User: /home/wida/go/src/runtime/proc.go:305 runtime.gopark (0x42faab)
Goroutine 5 - User: /home/wida/go/src/runtime/lock_futex.go:228 runtime.notetsleepg (0x40ab14)
Goroutine 17 - User: /home/wida/go/src/runtime/proc.go:305 runtime.gopark (0x42faab)
Goroutine 18 - User: /home/wida/go/src/runtime/time.go:105 time.Sleep (0x44aa51)
[7 goroutines]
(dlv) goroutine 18
Switched from 1 to 18 (thread 1903)
重启和退出
restart重新执行程序，设置的断点还会在。exit退出调试程序。
(dlv) b main.main
Breakpoint 1 set at 0x4aa3f8 for main.main() ./main.go:12
(dlv) breakpoints
Breakpoint runtime-fatal-throw at 0x42ddc0 for runtime.fatalthrow() /home/wida/go/src/runtime/panic.go:820 (0)
Breakpoint unrecovered-panic at 0x42de30 for runtime.fatalpanic() /home/wida/go/src/runtime/panic.go:847 (0)
print runtime.curg._panic.arg
Breakpoint 1 at 0x4aa3f8 for main.main() ./main.go:12 (0)
(dlv) restart
Process restarted with PID 2622
(dlv) breakpoints
Breakpoint runtime-fatal-throw at 0x42ddc0 for runtime.fatalthrow() /home/wida/go/src/runtime/panic.go:820 (0)
Breakpoint unrecovered-panic at 0x42de30 for runtime.fatalpanic() /home/wida/go/src/runtime/panic.go:847 (0)
print runtime.curg._panic.arg
Breakpoint 1 at 0x4aa3f8 for main.main() ./main.go:12 (0)
(dlv) exit
调试汇编代码
regs [-a]查看cpu通用寄存器值，加上-a的话查看所有的寄存器的值。disassemble查看汇编代码（inter 风格的汇编）
我们在原先代码目录添加一个汇编代码文件 test.s
#include "textflag.h"
TEXT ·add(SB), NOSPLIT, $0-8
MOVQ a+0(FP), AX
MOVQ b+8(FP), BX
ADDQ AX, BX
MOVQ BX, ret+16(FP)
RET
修改下main.go的代码
package main
import (
"fmt"
"time"
)
func add(a ,b int) int
func test(a int) int {
d :=3
a = d+3
return a
}
func main() {
a ,b:=1,3
for i:=0;i<5;i++ {
a++
}
test(a)
add(a,b)
go func() {
a +=1
b -=1
time.Sleep(10e9)
b +=1
}()
fmt.Println(a,b)
time.Sleep(100e9)
}
(dlv) c
> main.main() ./main.go:20 (hits goroutine(1):1 total:1) (PC: 0x4aa4bf)
15: a ,b:=1,3
16: for i:=0;i<5;i++ {
17: a++
18: }
19: test(a)
=> 20: add(a,b)
21: go func() {
22: a +=1
23: b -=1
24: time.Sleep(10e9)
25: b +=1
(dlv) s
> main.add() ./test.s:4 (PC: 0x4aa6d0)
1: #include "textflag.h"
2:
3: TEXT ·add(SB), NOSPLIT, $0-8
=> 4: MOVQ a+0(FP), AX
5: MOVQ b+8(FP), BX
6: ADDQ AX, BX
7: MOVQ BX, ret+16(FP)
8: RET
(dlv) regs
Rip = 0x00000000004aa6d0
Rsp = 0x000000c000075e78
Rax = 0x0000000000000003
...
(dlv) n
> main.add() ./test.s:5 (PC: 0x4aa6d5)
1: #include "textflag.h"
2:
3: TEXT ·add(SB), NOSPLIT, $0-8
4: MOVQ a+0(FP), AX
=> 5: MOVQ b+8(FP), BX
6: ADDQ AX, BX
7: MOVQ BX, ret+16(FP)
8: RET
(dlv) regs
Rip = 0x00000000004aa6d5
Rsp = 0x000000c000075e78
Rax = 0x0000000000000006 //rax 寄存器的值已经发送变化
...
(dlv) regs -a
Rip = 0x00000000004aa6d5
Rsp = 0x000000c000075e78
Rax = 0x0000000000000006
...
XMM0 = 0x00000000000000000000000000000000 v2_int={ 0000000000000000 0000000000000000 } v4_int={ 00000000 00000000 00000000 00000000 } v8_int={ 0000 0000 0000 0000 0000 0000 0000 0000 } v16_int={ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 } v2_float={ 0 0 } v4_float={ 0 0 0 0 }
...
(dlv)
(dlv) c
> main.main() ./main.go:20 (hits goroutine(1):1 total:1) (PC: 0x4aa4bf)
15: a ,b:=1,3
16: for i:=0;i<5;i++ {
17: a++
18: }
19: test(a)
=> 20: add(a,b)
21: go func() {
22: a +=1
23: b -=1
24: time.Sleep(10e9)
25: b +=1
(dlv) disassemble
TEXT main.main(SB) /home/wida/gocode/debugger-demo/main.go
main.go:14 0x4aa3e0 64488b0c25f8ffffff mov rcx, qword ptr fs:[0xfffffff8]
main.go:14 0x4aa3e9 488d4424a8 lea rax, ptr [rsp-0x58]
main.go:14 0x4aa3ee 483b4110 cmp rax, qword ptr [rcx+0x10]
...
dlv exec 调试可执行文件
我们先编译我们的项目
$ go build
$ ll
drwxr-xr-x 3 wida wida 4096 10月 22 11:01 .
drwxr-xr-x 44 wida wida 4096 10月 21 18:25 ..
-rwxr-xr-x 1 wida wida 2013047 10月 22 11:01 debugger-demo
-rw-r--r-- 1 wida wida 30 10月 21 18:38 go.mod
-rw-r--r-- 1 wida wida 288 10月 22 10:40 main.go
-rw-r--r-- 1 wida wida 143 10月 22 10:41 test.s
$ dlv exec ./debugger-demo
(dlv) b main.main
Breakpoint 1 set at 0x48cef3 for main.main() ./main.go:14
(dlv) c
> main.main() ./main.go:14 (hits goroutine(1):1 total:1) (PC: 0x48cef3)
Warning: debugging optimized function
9: func test(a int) int {
10: d :=3
11: a = d+3
12: return a
13: }
=> 14: func main() {
15: a ,b:=1,3
16: for i:=0;i<5;i++ {
17: a++
18: }
19: test(a)
(dlv) q
后面的调试方式和dlv exec类似。