GDB（GNU Project Debugger）是在Linux環(huán)境下功能全面的調(diào)試工具。它提供了一系列強(qiáng)大的調(diào)試功能，包括設(shè)置斷點(diǎn)、單步執(zhí)行、打印與觀察變量、查看寄存器及堆棧信息等。在Linux軟件開發(fā)的實(shí)踐中，GDB被視為調(diào)試C及C++程序的核心工具，廣泛用于幫助開發(fā)者定位和解決程序中的問題。

1. 虛擬機(jī)中安裝GDB工具

為避免符號(hào)解析錯(cuò)誤或架構(gòu)不兼容問題，用于遠(yuǎn)程調(diào)試的GDB應(yīng)在版本上與開發(fā)板的工具鏈對(duì)齊。

elf@ubuntu:~/work/EDU/sdk/ELF2-linux-source$ ./build.sh bconfig

路徑：

->Toolchain

選擇GDB版本，這里選擇gdb12.x

2. 文件系統(tǒng)添加gdbserver功能

elf@ubuntu:~/work/EDU/sdk/ELF2-linux-source$./build.sh bconfig

路徑：

-> Target packages -> Debugging, profiling and benchmark

3. 重新編譯

elf@ubuntu:~/work/EDU/sdk/ELF2-linux-source$./build.sh buildroot

這樣就可以將軟件包直接編譯到文件系統(tǒng)的鏡像中了。

4. 燒寫文件系統(tǒng)

5. 應(yīng)用編譯及拷貝

elf@ubuntu:~/work$vi gdbdemo.c

例程代碼如下：

#include int main() { int a = 10; int b = 20; int sum = a + b; printf("a = %d, b = %d\n", a, b); printf("sum = %d\n", sum); for (int i = 0; i < 5; i++) { printf("Loop i = %d\n", i); } return 0; }

添加交叉編譯器路徑，進(jìn)行交叉編譯，編譯要調(diào)試的應(yīng)用程序：必須要加-g選項(xiàng)

elf@ubuntu:~/work$ export PATH=/home/elf/aarch64-buildroot-linux-gnu_sdk-buildroot/bin/:$PATH elf@ubuntu:~/work$ aarch64-linux-gcc -g gdbdemo.c -o gdbdemo

將編譯生成的gdbdemo通過U盤拷貝到開發(fā)板上，比如/home/elf路徑下，下述以U盤為例，拷貝到開發(fā)板。

root@elf2-buildroot:~#cp/mnt/udisk/gdbdemo /home/elf

6. 設(shè)置開發(fā)板IP和端口號(hào)

root@elf2-buildroot:~# gdbserver 172.20.8.7:2345 /home/elf/gdbdemo Process /home/elf/gdbdemo created; pid = 1314 Listening on port 2345

7. 給虛擬機(jī)設(shè)置同網(wǎng)段的IP并保證可以ping通開發(fā)板IP

8. 調(diào)試

GDB工具所在路徑：

ELF2-linux-source/buildroot/output/elf2_fs/host/bin/aarch64-linux-gdb

elf@ubuntu:~/work$ ./EDU/sdk/ELF2-linux-source/buildroot/output/elf2_fs/host/bin/aarch64-linux-gdb gdbdemo GNU gdb (GDB) 12.1 Copyright (C) 2022 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "--host=x86_64-pc-linux-gnu --target=aarch64-buildroot-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: . Find the GDB manual and other documentation resources online at: . For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from gdbdemo... (gdb) target remote 172.20.8.7:2345 //連接開發(fā)板 Remote debugging using 172.20.8.7:2345 Reading /lib/ld-linux-aarch64.so.1 from remote target... warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead. Reading /lib/ld-linux-aarch64.so.1 from remote target... Reading symbols from target:/lib/ld-linux-aarch64.so.1... (No debugging symbols found in target:/lib/ld-linux-aarch64.so.1) Reading /home/elf/work/EDU/sdk/ELF2-linux-source/buildroot/output/elf2_fs/host/lib/debug/.build-id/01/bd8db25550e790a84285a6377baa031748d93c.debug from remote target... 0x0000007ff7ff1900 in _start () from target:/lib/ld-linux-aarch64.so.1 (gdb)

此時(shí)就可以根據(jù)需求進(jìn)行調(diào)試了，下面是幾個(gè)常用的命令

（1）l：列出所有源代碼

（2）b：設(shè)置斷點(diǎn)

（3）c：運(yùn)行到斷點(diǎn)處

（4）s：單步運(yùn)行執(zhí)行

（5）n：單步執(zhí)行，但是step會(huì)進(jìn)入函數(shù)里面，但是next不會(huì)

（6）p a：打印a這個(gè)變量的值

（7）q：退出，輸入此命令則開發(fā)板上的gdbserver也退出

下面以具體示例介紹參數(shù)的使用方法。

(gdb) l //列出源代碼 1 #include 2 3int main() { 4 int a = 10; 5 int b = 20; 6 int sum = a + b; 7 8 printf("a = %d, b = %d\n", a, b); 9 printf("sum = %d\n", sum); 10 (gdb) b 9 //在第9行設(shè)置斷點(diǎn) Breakpoint 1 at 0x55555557d0: file gdbdemo.c, line 9. (gdb) c // 繼續(xù)執(zhí)行程序，直到遇到斷點(diǎn)，此時(shí)終端打印a = 10, b = 20 Continuing. Reading /lib/libc.so.6 from remote target... Breakpoint 1, main () at gdbdemo.c:9 9 printf("sum = %d\n", sum); (gdb) c //從當(dāng)前斷點(diǎn)繼續(xù)執(zhí)行到程序結(jié)束。 Continuing. [Inferior 1 (process 1367) exited normally] (gdb)