嵌入式设备上Bazel编译程序的本地GDB调试断点失效问题

编译配置与过程 #

使用Bazel结合TDA4 SOC交叉编译工具链编译hello-world程序，BUILD文件内容：

$ cat examples/hello_world/BUILD
cc_binary(
    name = "hello_world",
    srcs = ["hello_world.cpp"],
)

编译命令及输出：

$ bazel build --cxxopt=-std=c++11 --config=tda4 --copt=-DWITH_TDA4 --subcommands --copt=-DFOOFXXX -c dbg --strip=never //examples/hello_world:hello_world
Starting local Bazel server and connecting to it...

INFO: Analyzed target //examples/hello_world:hello_world (41 packages loaded, 40489 targets configured).
INFO: Found 1 target...
SUBCOMMAND: # //examples/hello_world:hello_world [action 'Compiling examples/hello_world/main.cpp', configuration: e23aa3bce872abfb8f06c09952a42b5c1c7714b1c55b5bf022d91a6582852828, execution platform: @local_config_platform//:host]
(cd /home/wss/.cache/bazel/_bazel_wss/4112892ab2eb09dee5980f588ac10e42/execroot/com_minieye_aiplorer && \
  exec env - \
    LD_LIBRARY_PATH=/opt/ros/melodic/lib \
    PATH=/opt/ros/melodic/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin \
    PWD=/proc/self/cwd \
  bazel/toolchain/aarch64-none-linux-gnu/wrappers/aarch64-none-linux-gnu-gcc -MD -MF bazel-out/aarch64-dbg/bin/examples/hello_world/_objs/hello_world/main.d '-frandom-seed=bazel-out/aarch64-dbg/bin/examples/hello_world/_objs/hello_world/main.o' '-DBAZEL_CURRENT_REPOSITORY=""' -iquote . -iquote bazel-out/aarch64-dbg/bin -iquote external/bazel_tools -iquote bazel-out/aarch64-dbg/bin/external/bazel_tools '--sysroot=external/aarch64-none-linux-gnu-sysroot' -no-canonical-prefixes -fno-canonical-system-headers -Wno-builtin-macro-redefined '-D__DATE__="redacted"' '-D__TIMESTAMP__="redacted"' '-D__TIME__="redacted"' -DWITH_TDA4 -DFOOFXXX '-std=c++11' -c examples/hello_world/main.cpp -o bazel-out/aarch64-dbg/bin/examples/hello_world/_objs/hello_world/main.o)
# Configuration: e53aa3bce872abfb8f06c29952a42b5c1c7714b1c55b5bf022d91a6582852828
# Execution platform: @local_config_platform//:host
SUBCOMMAND: # //examples/hello_world:hello_world [action 'Linking examples/hello_world/hello_world', configuration: e23aa3bce872abfb8f06c09952a42b5c1c7714b1c55b5bf022d91a6582852828, execution platform: @local_config_platform//:host]
(cd /home/wss/.cache/bazel/_bazel_wss/4112892ab2eb09dee5980f588ac10e42/execroot/com_minieye_aiplorer && \
  exec env - \
    LD_LIBRARY_PATH=/opt/ros/melodic/lib \
    PATH=/opt/ros/melodic/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin \
    PWD=/proc/self/cwd \
  bazel/toolchain/aarch64-none-linux-gnu/wrappers/aarch64-none-linux-gnu-gcc @bazel-out/aarch64-dbg/bin/examples/hello_world/hello_world-2.params)
# Configuration: e23aa3bce872abfb8f06c09952a42b5c1c7714b1c55b5bf022d91a6582852828
# Execution platform: @local_config_platform//:host
Target //examples/hello_world:hello_world up-to-date:
  bazel-bin/examples/hello_world/hello_world
INFO: Elapsed time: 5.316s, Critical Path: 1.37s
INFO: 6 processes: 4 internal, 2 linux-sandbox.
INFO: Build completed successfully, 6 total actions

说明：--config=tda4指定TDA4交叉编译工具链；生成的可执行文件含.debug_info段（大小0x288），--fission=no为默认值，添加后无变化。

编译产物验证 #

检查可执行文件属性：

$ file bazel-bin/examples/hello_world/hello_world
bazel-bin/examples/hello_world/hello_world: ELF 64-bit LSB executable, ARM aarch64,   
version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1,    
for GNU/Linux 3.7.0, with debug_info, not stripped

查看调试段信息：

$ readelf -WS bazel-bin/examples/hello_world/hello_world |grep -E "Address|debug"
[Nr] Name             Type        Address          Off    Size   ES Flg Lk Inf Al
[26] .debug_aranges   PROGBITS    0000000000000000 0010c0 000110 00      0   0 16
[27] .debug_info      PROGBITS    0000000000000000 0011d0 000288 00      0   0  1
[28] .debug_abbrev    PROGBITS    0000000000000000 001458 00019c 00      0   0  1
[29] .debug_line      PROGBITS    0000000000000000 0015f4 0002d3 00      0   0  1
[30] .debug_str       PROGBITS    0000000000000000 0018c7 000338 01  MS  0   0  1
[31] .debug_loc       PROGBITS    0000000000000000 001bff 00019b 00      0   0  1
[32] .debug_ranges    PROGBITS    0000000000000000 001da0 0000c0 00      0   0 16

目标设备调试问题 #

将可执行文件和源码目录拷贝到设备/app/bin后，GDB调试无法关联源码：

$ gdb hello_world
Reading symbols from hello_world...
(gdb) set directories /app/bin/examples/hello_world
(gdb) shell cat -n /app/bin/examples/hello_world/hello_world.cpp  |tail -10
     5  int fun(int a, int b)
     6  {
     7     return a+b;
     8  }
     9  int main(int argc, char *argv[]) {
    10    std::cout << "WITH LINUX~~~" << std::endl;
    11    int c=fun(1,1);
    12    std::cout << "Hello World!" << std::endl;
    13    std::cout<<c<<std::endl;
    14    return 0;
    15  }
(gdb) b hello_world.cpp:10
No source file named hello_world.cpp.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (hello_world.cpp:10) pending.
(gdb) b hello_world.cpp:11
No source file named hello_world.cpp.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (hello_world.cpp:11) pending.
(gdb) i b
Num     Type           Disp Enb Address    What
1       breakpoint     keep y   <PENDING>  hello_world.cpp:10
2       breakpoint     keep y   <PENDING>  hello_world.cpp:11
(gdb) r
Starting program: /app/bin/hello_world
WITH LINUX~~~
Hello World!
2
[Inferior 1 (process 17279) exited normally]

断点处于pending状态无法触发，程序直接正常退出。

解决方法 #

1. 查看调试信息中的源码路径
   执行readelf -w bazel-bin/examples/hello_world/hello_world | grep -E "file:|name:"，会发现Bazel编译时记录的是构建沙箱内的绝对路径（如/home/wss/.cache/bazel/.../execroot/com_minieye_aiplorer/examples/hello_world/main.cpp），而非相对路径的hello_world.cpp。

2. 修改Bazel编译配置，生成相对路径调试信息
   在BUILD文件中添加编译选项，将沙箱路径替换为相对路径：

   cc_binary(
       name = "hello_world",
       srcs = ["hello_world.cpp"],
       copts = ["-fdebug-prefix-map=$(execroot)=."],
   )
   

   也可以在编译命令中添加参数：--copt=-fdebug-prefix-map=$(bazel info execution_root)=.

3. 在GDB中设置路径映射
   无需修改编译配置，直接在GDB中映射沙箱路径到设备源码路径：

   (gdb) set substitute-path /home/wss/.cache/bazel/_bazel_wss/4112892ab2eb09dee5980f588ac10e42/execroot/com_minieye_aiplorer /app/bin
   

   映射完成后即可正常设置断点关联源码。

4. 确认GDB版本兼容性
   确保设备上的GDB版本与交叉编译工具链的GDB版本匹配，避免版本差异导致调试信息解析失败。

内容的提问来源于stack exchange，提问作者wssbygone