Although the GoLand editor is very powerful, it is still relatively weak in displaying memory and stack information. Maybe my posture is wrong. So, I started to debug the gdb, but the GDB stepped into the pit and did not solve it, which triggered the comparison between GDB and dlv.
gdb
install
yum install ncures-devel wget http://ftp.gnu.org/gnu/gdb/gdb-8.2.tar.gz tar zxf gdb-8.2.tar.gz cd gdb-8.2 make && make install
Enter debugging
go build -gcflags '-N -l' main.go gdb main
Use
-
Start Debugger (gdb)
[lday@alex GoDbg]$ gdb ./GoDbg -
Setting breakpoints on main function (b)
(gdb) b main.main Breakpoint 1 at 0x401000: file /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go, line 9. -
Start program with parameters (r)
(gdb) r arg1 arg2 Starting program: /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/GoDbg arg1 arg2 [New LWP 8412] [New LWP 8413] [New LWP 8414] [New LWP 8415] Breakpoint 1, main.main () at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go:9 9 func main() { -
Set breakpoints on the file dbgTest.go by line number (b)
(gdb) b dbgTest.go:16 Breakpoint 3 at 0x457960: file /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/mylib/dbgTest.go, line 16. -
View breakpoint settings (info b)
(gdb) info b Num Type Disp Enb Address What 1 breakpoint keep y 0x0000000000401000 in main.main at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go:9 breakpoint already hit 1 time 2 breakpoint keep y 0x0000000000401000 in main.main at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go:9 breakpoint already hit 1 time 3 breakpoint keep y 0x0000000000457960 in GoWorks/GoDbg/mylib.DBGTestRun at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/mylib/dbgTest.go:16 -
Disable breakpoints (dis n)
(gdb) dis 1 (gdb) info b Num Type Disp Enb Address What 1 breakpoint keep n 0x0000000000401000 in main.main at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go:9 breakpoint already hit 1 time 2 breakpoint keep y 0x0000000000401000 in main.main at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go:9 breakpoint already hit 1 time 3 breakpoint keep y 0x0000000000457960 in GoWorks/GoDbg/mylib.DBGTestRun at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/mylib/dbgTest.go:16 -
Delete breakpoints (del n)
(gdb) del 1 (gdb) info b Num Type Disp Enb Address What 2 breakpoint keep y 0x0000000000401000 in main.main at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go:9 breakpoint already hit 1 time 3 breakpoint keep y 0x0000000000457960 in GoWorks/GoDbg/mylib.DBGTestRun at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/mylib/dbgTest.go:16 -
Continue execution after breakpoint (c)
(gdb) c Continuing. Golang dbg test... argc:3 argv:[/home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/GoDbg arg1 arg2] Breakpoint 3, GoWorks/GoDbg/mylib.DBGTestRun (var1=1, var2="golang dbg test") at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/mylib/dbgTest.go:16 16 func DBGTestRun(var1 int, var2 string, var3 []int, var4 MyStruct) { (gdb) -
Display code (l)
(gdb) l 11 B string 12 C map[int]string 13 D []string 14 } 15 16 func DBGTestRun(var1 int, var2 string, var3 []int, var4 MyStruct) { 17 fmt.Println("DBGTestRun Begin!\n") 18 waiter := &sync.WaitGroup{} 19 20 waiter.Add(1) -
Single step execution (n)
(gdb) n DBGTestRun Begin! 18 waiter := &sync.WaitGroup{} -
Print variable information (print/p)
Set a breakpoint (b dbgTest.go:16) where you enter the DBGTestRun. After entering the function, display the corresponding variables through the p command:(gdb) l 17 12 C map[int]string 13 D []string 14 } 15 16 func DBGTestRun(var1 int, var2 string, var3 []int, var4 MyStruct) { 17 fmt.Println("DBGTestRun Begin!\n") 18 waiter := &sync.WaitGroup{} 19 20 waiter.Add(1) 21 go RunFunc1(var1, waiter) (gdb) p var1 $3 = 1 (gdb) p var2 $4 = "golang dbg test" (gdb) p var3 No symbol "var3" in current context.From the above output, we can see a very strange thing. Although DBGTestRun has four parameters passed in, it seems that var3 and var4 gdb can not be recognized. In the subsequent experiments on dlv, we found that DLV can recognize var3 and var4.
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View the call stack (bt), switch the call stack (f n), and display the current stack variable information
(gdb) bt #0 GoWorks/GoDbg/mylib.DBGTestRun (var1=1, var2="golang dbg test") at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/mylib/dbgTest.go:17 #1 0x00000000004018c2 in main.main () at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go:27 (gdb) f 1 #1 0x00000000004018c2 in main.main () at /home/lday/Works/Go_Works/GoLocalWorks/src/GoWorks/GoDbg/main.go:27 27 mylib.DBGTestRun(var1, var2, var3, var4) (gdb) l 22 var4.A = 1 23 var4.B = "golang dbg my struct field B" 24 var4.C = map[int]string{1: "value1", 2: "value2", 3: "value3"} 25 var4.D = []string{"D1", "D2", "D3"} 26 27 mylib.DBGTestRun(var1, var2, var3, var4) 28 fmt.Println("Golang dbg test over") 29 } (gdb) print var1 $5 = 1 (gdb) print var2 $6 = "golang dbg test" (gdb) print var3 $7 = []int = {1, 2, 3} (gdb) print var4 $8 = {A = 1, B = "golang dbg my struct field B", C = map[int]string = {[1] = "value1", [2] = "value2", [3] = "value3"}, D = []string = {"D1", "D2", "D3"}}
DLV (Recommendation)
install
go get -u github.com/go-delve/delve/cmd/dlv
Enter debugging
dlv debug main.go
Use
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 ------------------- Shows or changes current goroutine goroutines ------------------ 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.
summary
- dlv supports goroutine better. I did not find a way to debug goroutine using gdb. Maybe the posture is wrong.
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gdb cannot debug locally referenced variables, dlv does not
func main() { i := 10 j := &i }As shown in the above code, when gdb prints variable j with pj, dlv can
- dlv can't debug some internal structures of Go such as interface. gdb is possible