如何将地址转换为类型并在GDB for Golang中打印它

Question

这是一段代码:

package main

import (
    "fmt"
)

type TestType struct {
    a int
    b int
}

func main() {
    var testType TestType = TestType{1, 2}
    fmt.Println(testType)
}

这是gdb调试输出:

(gdb) r
Starting program: /home/bzhang/common/src/go/src/test/testBinary 

Breakpoint 1, main.main () at /home/bzhang/common/src/go/src/test/main.go:14
14              fmt.Println(testType)
(gdb) p testType
$1 = {a = 1, b = 2}
(gdb) p &testType
$2 = (main.TestType *) 0xc820059ee8
(gdb) p ('main.TestType'*) 0xc820059ee8
A syntax error in expression, near `) 0xc820059ee8'.
(gdb) p ('TestType'*) 0xc820059ee8     
A syntax error in expression, near `) 0xc820059ee8'.
(gdb) whatis testType
type = main.TestType
(gdb) 

当然我知道我可以直接打印testType.但如果它是局部变量,有时它的值不能直接打印出来,只有它的地址可用.所以我想用它的类型指示打印它的值.但它似乎无法正常工作.感谢您的帮助!

Answer 1

delve 工具比 gdb 更好。https://github.com/go-delve/delve

1. 安装钻探

go get -u github.com/go-delve/delve/cmd/dlv

2. 在 main.go 上移动路径

cd $GOPATH/src/YOUPROJECT/main.go

3. 调试钻研

$GOPATH/bin/delve debug main.go

4. 主断点

Type 'help' for list of commands.
(dlv) b main.main
Breakpoint 1 set at 0x4a7bbf for main.main() main.go:12

5. 跑步

(dlv) c
> main.main() main.go:12 (hits goroutine(1):1 total:1) (PC: 0x4a7bbf)
     7: type TestType struct {
     8:         a int
     9:         b int
    10: }
    11:
=>  12: func main() {
    13:         var testType TestType = TestType{1, 2}
    14:         fmt.Println(testType)
    15: }

6. 断点14行

(dlv) b 14
Breakpoint 2 set at 0x4a7bf0 for main.main() main.go:14

7. 继续

(dlv) c
> main.main() main.go:14 (hits goroutine(1):1 total:1) (PC: 0x4a7bf0)
     9:         b int
    10: }
    11:
    12: func main() {
    13:         var testType TestType = TestType{1, 2}
=>  14:         fmt.Println(testType)
    15: }

8. 显示价值

(dlv) locals
testType = main.TestType {a: 1, b: 2}

最后，使用goland、vscode进行调试更加方便。