如何在GDB中调试libgcc源代码？ Ubuntu 14.04.1

我想在Ubuntu 14.04.1的源代码级别的GDB中调试libgcc_s.so.1 。 所以我下载了libgcc1-dbg并获得了gcc的源代码。

在GDB中，我使用directory来指定gcc源目录。 但是当我在GDB中出现一些问题，并在libgcc_s.so.1中断时，我无法获得源代码。

 Reading symbols from /home/love/pri...(no debugging symbols found)...done. (gdb) directory ~/source/gcc-4.9/ Source directories searched: /home/lovelydream/source/gcc-4.9:$cdir:$cwd (gdb) c The program is not being run. (gdb) run Starting program: /home/lovelydream/prison warning: no loadable sections found in added symbol-file system-supplied DSO at 0x7ffff7ffa000 > Program received signal SIGINT, Interrupt. 0x00007ffff75e6350 in __read_nocancel () at ../sysdeps/unix/syscall-template.S:81 81 ../sysdeps/unix/syscall-template.S: 没有那个文件或目录. (gdb) b _Unwind_Find_FDE Breakpoint 1 at 0x7ffff78d20c0 (gdb) c Continuing. x Breakpoint 1, 0x00007ffff78d20c0 in _Unwind_Find_FDE () from /lib/x86_64-linux-gnu/libgcc_s.so.1 (gdb) info source Current source file is ../sysdeps/unix/syscall-template.S Compilation directory is /build/buildd/eglibc-2.19/io Source language is asm. Compiled with DWARF 2 debugging format. Does not include preprocessor macro info. (gdb) ni 0x00007ffff78d20c2 in _Unwind_Find_FDE () from /lib/x86_64-linux-gnu/libgcc_s.so.1 (gdb) directory ~/source/gcc-4.9/ Source directories searched: /home/lovelydream/source/gcc-4.9:$cdir:$cwd (gdb) ni 0x00007ffff78d20c4 in _Unwind_Find_FDE () from /lib/x86_64-linux-gnu/libgcc_s.so.1 (gdb) list 76 ../sysdeps/unix/syscall-template.S: 没有那个文件或目录. (gdb) list 76 in ../sysdeps/unix/syscall-template.S (gdb) list 76 in ../sysdeps/unix/syscall-template.S (gdb) info source