dlv golang调试

dlv go调试

dlv模式的几种方式

1、dlv attach pid

2、dlv run|debug run命令已被debug命令取代，运行dlv debug test.go会先编译go源文件，同时执行attach命令进入调试模式，该命令会在当前目录下生成一个名为debug的可执行二进制文件，退出调试模式会自动被删除。

3、 dlv exec executable_file：直接从二进制文件启动调试模式。

4、 dlv core executable_file core_file：以core文件启动调试，通常进行dlv的目的就是为了找出可执行文件core的原因，通过core文件可直接找出具体进程异常的信息。

5、dlv trace：该命令最直接的用途是可以追踪代码里函数的调用轨迹，可通过help查看其调用方式。

dlv trace main.go Test 

dlv help

(dlv) help The following commands are available: Running the program: call ------------------------ Resumes process, injecting a function call (EXPERIMENTAL!!!) continue (alias: c) --------- Run until breakpoint or program termination. next (alias: n) ------------- Step over to next source line. rebuild --------------------- Rebuild the target executable and restarts it. It does not work if the executable was not built by delve. restart (alias: r) ---------- Restart process. 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. Manipulating breakpoints: break (alias: b) ------- Sets a breakpoint. breakpoints (alias: bp) Print out info for active breakpoints. clear ------------------ Deletes breakpoint. clearall --------------- Deletes multiple breakpoints. condition (alias: cond) Set breakpoint condition. on --------------------- Executes a command when a breakpoint is hit. toggle ----------------- Toggles on or off a breakpoint. trace (alias: t) ------- Set tracepoint. watch ------------------ Set watchpoint. Viewing program variables and memory: args ----------------- Print function arguments. display -------------- Print value of an expression every time the program stops. examinemem (alias: x) Examine raw memory at the given address. locals --------------- Print local variables. print (alias: p) ----- Evaluate an expression. regs ----------------- Print contents of CPU registers. set ------------------ Changes the value of a variable. vars ----------------- Print package variables. whatis --------------- Prints type of an expression. Listing and switching between threads and goroutines: goroutine (alias: gr) -- Shows or changes current goroutine goroutines (alias: grs) List program goroutines. thread (alias: tr) ----- Switch to the specified thread. threads ---------------- Print out info for every traced thread. Viewing the call stack and selecting frames: deferred --------- Executes command in the context of a deferred call. down ------------- Move the current frame down. frame ------------ Set the current frame, or execute command on a different frame. stack (alias: bt) Print stack trace. up --------------- Move the current frame up. Other commands: config --------------------- Changes configuration parameters. disassemble (alias: disass) Disassembler. dump ----------------------- Creates a core dump from the current process state edit (alias: ed) ----------- Open where you are in $DELVE_EDITOR or $EDITOR exit (alias: quit | q) ----- Exit the debugger. funcs ---------------------- Print list of functions. help (alias: h) ------------ Prints the help message. libraries ------------------ List loaded dynamic libraries list (alias: ls | l) ------- Show source code. source --------------------- Executes a file containing a list of delve commands sources -------------------- Print list of source files. transcript ----------------- Appends command output to a file. types ---------------------- Print list of types Type help followed by a command for full documentation. 

常用的指令

设置断点

b test main.go:11 

查看所有断点

(dlv) bp Breakpoint runtime-fatal-throw (enabled) at 0x4366c0 for runtime.throw() c:/program files/go/src/runtime/panic.go:1188 (0) Breakpoint unrecovered-panic (enabled) at 0x436a20 for runtime.fatalpanic() c:/program files/go/src/runtime/panic.go:1271 (0) print runtime.curg._panic.arg Breakpoint 1 (enabled) at 0x4b65b4 for main.Bar() d:/go/src/demo/string/main.go:9 (1) Breakpoint 2 (enabled) at 0x4b6606 for main.Bar() d:/go/src/demo/string/main.go:11 (1) 

在断点处加打印

on 1 p name 

删除断点

clear 1 clearall 

list：打印当前断点位置的源代码，list后面加行号可以展示该行附近的源代码，如list test.go:10将会展示test.go文件第10行附近的代码，值得注意的是该行必须是代码行而不能是空行。

list main.go:18 

condition ：有条件的中断断点，当expression为true时指定的断点将被中断，程序将继续执行。

conditon 2 a==105 # 断点2在a==105条件下中断 

toggle：打开或者关闭一个断点

toggle 2 

next|step：逐行执行代码，区别和gdb类似，next遇到函数调用时不会进入该函数，step则会进入函数，如果需要查看函数的具体执行过程则用step，否则用next

locals：查看局部变量

 11: func main() { 
    12: 13: var a = 100 14: for i := 0; i < 3; i++ { 
    15: a++ => 16: Print(i) 17: } 18: } (dlv) locals a = 103 i = 2 (dlv) locals a a = 103 

args：查看函数参数

 4: => 5: func Print(i int) { 
    6: fmt.Println(i) 7: } 8: (dlv) args i = 2 (dlv) args i i = 2 

bt：打印栈信息

(dlv) bt 0 0x00000000004a2c7f in main.main at d:/go/src/demo/string/main.go:22 1 0x00000000004384d7 in runtime.main at c:/program files/go/src/runtime/proc.go:255 2 0x00000000004605a1 in runtime.goexit at c:/program files/go/src/runtime/asm_amd64.s:1581 

frame：切换栈

frame 0 

regs：打印寄存器内容

(dlv) regs Rip = 0x00000000004a2bd4 Rsp = 0x000000c00007be90 Rax = 0x0000000000000004 Rbx = 0x0000000000000000 Rcx = 0x0000000000000000 Rdx = 0x0000000000000004 Rsi = 0x000000c000022b60 Rdi = 0x000000c00007e008 Rbp = 0x000000c00007bed8 R8 = 0x0000000000000000 R9 = 0x0000000000000004 R10 = 0x0000000000000000 R11 = 0x0000000000000004 

goroutines：打印goroutines

func Fuc(value int, wg *sync.WaitGroup) { fmt.Println(value) wg.Done() } func main() { wg := sync.WaitGroup{} for i := 0; i < 10; i++ { wg.Add(1) go Fuc(i, &wg) } wg.Wait() fmt.Println("finish") } 

(dlv) goroutines Goroutine 1 - User: d:/go/src/demo/string/main.go:28 main.main (0x4a30b8) (thread 6764) Goroutine 2 - User: c:/program files/go/src/runtime/proc.go:367 runtime.gopark (0x4388d2) [force gc (idle)] Goroutine 3 - User: c:/program files/go/src/runtime/proc.go:367 runtime.gopark (0x4388d2) [GC sweep wait] Goroutine 4 - User: c:/program files/go/src/runtime/proc.go:367 runtime.gopark (0x4388d2) [GC scavenge wait] Goroutine 5 - User: c:/program files/go/src/runtime/proc.go:367 runtime.gopark (0x4388d2) [finalizer wait] * Goroutine 6 - User: d:/go/src/demo/string/main.go:20 main.Fuc (0x4a2f22) (thread 11840) Goroutine 7 - User: d:/go/src/demo/string/main.go:28 main.main·dwrap·1 (0x4a3140) Goroutine 8 - User: d:/go/src/demo/string/main.go:28 main.main·dwrap·1 (0x4a3140) [8 goroutines] 

goroutine：协程切换。dlv默认会一直在主协程上执，为打印Func函数中的临时变量a，需要进行协程切换，先执行goroutine 5表示切换到5号协程上，然后bt命令查看当前协程的栈状态，执行frame 3 locals切换到3号栈上并打印栈上的变量。

(dlv) goroutine 7 Switched from 8 to 7 (thread 12920) (dlv) bt 0 0x00000000004388d2 in runtime.gopark at c:/program files/go/src/runtime/proc.go:367 1 0x000000000045d57b in time.Sleep at c:/program files/go/src/runtime/time.go:193 2 0x00000000004a31eb in main.Fuc at d:/go/src/demo/string/main.go:21 3 0x00000000004a33d9 in main.main·dwrap·1 at d:/go/src/demo/string/main.go:29 4 0x0000000000 in runtime.goexit at c:/program files/go/src/runtime/asm_amd64.s:1581 (dlv) frame 2 > runtime.gopark() c:/program files/go/src/runtime/proc.go:367 (PC: 0x4388d2) Warning: debugging optimized function Frame 2: d:/go/src/demo/string/main.go:21 (PC: 4a31eb) Warning: listing may not match stale executable 16: fmt.Println("b") 17: } 18: 19: func Fuc(value int, wg *sync.WaitGroup) { 
    20: fmt.Println(value) => 21: time.Sleep(time.Second * 10) 22: wg.Done() 23: } 24: 25: func main() { 
    26: wg := sync.WaitGroup{ 
   } (dlv) args value = 1 wg = (*sync.WaitGroup)(0xc00000a0d0) 

sources：打印所有源代码路径

threads：显示所有线程，thread：线程切换，这两个命令与goroutines、goroutine类似，不过在go语言中一般很少使用。

trace：跟踪，类似于打断点，但是代码不会中断继续执行，同时打印一行信息。