我有一个用Pascal编写的脚本。我想以这种方式调试它：在每一行停止，将所有变量的值转储到内存中并转到下一行。是否可以使用gdb或其他一些Linux开源工具来实现？
答案 0 :(得分：3)
使用选项-g编译文件：
fpc/gpc -g file.pas
为此文件运行gdb：
gdb file
设置所有需要的变量：
display first_var
display second_var
...
开始调试：
start
按s即可继续下一行。
答案 1 :(得分：1)
我将提出一个概念验证，它逐步执行（单线程）程序，使用GDB的Python API转储所有变量：
# Usage: gdb -x dump-vars-each-step.py PROGRAM
import gdb
import re
import logging
LOG_LEVEL = logging.INFO
def dump_all_vars(skip_libc_symbols=True):
# gdb calls the source of its debug info an 'objfile'
# libc_objfile_name. e.g. '/usr/lib/debug/lib64/libc-2.16.so.debug'
libc_objfile_name_pattern = r'libc.*\.so'
frame = gdb.newest_frame()
while frame:
symtab = frame.find_sal().symtab
if symtab is not None:
objfile_name = symtab.objfile.filename
else:
objfile_name = ''
logging.debug('F: %s, %s' % (frame, objfile_name))
if skip_libc_symbols and re.match(r'libc.*\.so', os.path.basename(objfile_name)):
return
try:
block = frame.block()
except RuntimeError:
block = None
while block:
logging.debug('B: %s, %s' % (block, block.function))
for symbol in block:
try:
value = frame.read_var(symbol, block)
except gdb.error:
# typedefs etc don't have a value
pass
else:
sys.stdout.write('%s: %s\n' % (symbol, value))
block = block.superblock
frame = frame.newer()
def dump_globals(names):
for i in names:
s = gdb.lookup_global_symbol(i)
if s is not None:
sys.stdout.write('%s: %s\n' % (s, s.value()))
inferior_alive = False
def inferior_exited(e):
global inferior_alive
inferior_alive = False
sys.stdout.write('inferior exited with code: %d\n' % (e.exit_code))
def run_and_dump_vars_each_step():
# precondition: inferior not running
# NOTE: only handles single threaded programs
global inferior_alive
gdb.execute('start')
inferior_alive = True
gdb.events.exited.connect(inferior_exited)
while inferior_alive:
dump_all_vars()
gdb.execute('step')
gdb.execute('quit')
logging.basicConfig(format='%(message)s', level=LOG_LEVEL)
gdb.execute('set pagination no')
gdb.execute('set python print-stack full')
run_and_dump_vars_each_step()
鉴于以下C河内的Tower of Hanoi计划：
enum {
N = 2,
};
int peg_positions[N];
static void hanoi(int n, int src, int dst)
{
int tmp = (0 + 1 + 2) - src - dst;
if (n == 0) {
peg_positions[n] = dst;
return;
}
hanoi(n - 1, src, tmp);
peg_positions[n] = dst;
hanoi(n - 1, tmp, dst);
}
int main()
{
hanoi(N - 1, 0, 2);
return 0;
}
运行gcc -g hanoi.c -o hanoi然后gdb -x dump-vars-each-step.py hanoi打印：
Reading symbols from /home/scottt/work/gdb-python-scripts/hanoi...done.
Temporary breakpoint 1 at 0x400400: file hanoi.c, line 21.
Temporary breakpoint 1, main () at hanoi.c:21
21 {
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
22 hanoi(N - 1, 0, 2);
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
hanoi (n=n@entry=1, src=src@entry=0, dst=dst@entry=2) at hanoi.c:8
8 {
n: 1
src: 0
dst: 2
tmp: <optimized out>
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
9 int tmp = (0 + 1 + 2) - src - dst;
n: 1
src: 0
dst: 2
tmp: <optimized out>
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
8 {
n: 1
src: 0
dst: 2
tmp: <optimized out>
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
11 if (n == 0) {
n: 1
src: 0
dst: 2
tmp: 1
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
9 int tmp = (0 + 1 + 2) - src - dst;
n: 1
src: 0
dst: 2
tmp: 1
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
15 hanoi(n - 1, src, tmp);
n: 1
src: 0
dst: 2
tmp: 1
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
9 int tmp = (0 + 1 + 2) - src - dst;
n: 1
src: 0
dst: 2
tmp: 1
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
15 hanoi(n - 1, src, tmp);
n: 1
src: 0
dst: 2
tmp: 1
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
hanoi (n=n@entry=0, src=0, dst=dst@entry=1) at hanoi.c:8
8 {
n: 0
src: 0
dst: 1
tmp: <optimized out>
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
9 int tmp = (0 + 1 + 2) - src - dst;
n: 0
src: 0
dst: 1
tmp: <optimized out>
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
8 {
n: 0
src: 0
dst: 1
tmp: <optimized out>
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
11 if (n == 0) {
n: 0
src: <optimized out>
dst: 1
tmp: 2
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
12 peg_positions[n] = dst;
n: 0
src: <optimized out>
dst: 1
tmp: 2
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {0, 0}
18 }
n: 0
src: <optimized out>
dst: 1
tmp: 2
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {1, 0}
hanoi (n=n@entry=1, src=src@entry=0, dst=dst@entry=2) at hanoi.c:16
16 peg_positions[n] = dst;
n: 1
src: 0
dst: 2
tmp: <optimized out>
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {1, 0}
17 hanoi(n - 1, tmp, dst);
n: 1
src: 0
dst: 2
tmp: <optimized out>
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {1, 2}
11 if (n == 0) {
n: 1
src: 0
dst: 2
tmp: 0
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {1, 2}
12 peg_positions[n] = dst;
n: 1
src: 0
dst: 2
tmp: 0
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {1, 2}
18 }
n: 1
src: 0
dst: 2
tmp: 0
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {2, 2}
main () at hanoi.c:24
24 }
N: N
hanoi: {void (int, int, int)} 0x40050c <hanoi>
main: {int ()} 0x400400 <main>
peg_positions: {2, 2}
__libc_start_main (main=0x400400 <main>, argc=1, ubp_av=0x7fffffffde48, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffde38) at libc-start.c:257
257 exit (result);
__GI_exit (status=0) at exit.c:99
99 __run_exit_handlers (status, &__exit_funcs, true);
98 {
99 __run_exit_handlers (status, &__exit_funcs, true);
__run_exit_handlers (status=0, listp=0x3c777b16a8 <__exit_funcs>, run_list_atexit=run_list_atexit@entry=true) at exit.c:36
36 {
41 while (*listp != NULL)
45 while (cur->idx > 0)
48 &cur->fns[--cur->idx];
47 const struct exit_function *const f =
49 switch (f->flavor)
73 cxafct = f->func.cxa.fn;
77 cxafct (f->func.cxa.arg, status);
75 PTR_DEMANGLE (cxafct);
77 cxafct (f->func.cxa.arg, status);
0x00000000004004c0 in __do_global_dtors_aux ()
Single stepping until exit from function __do_global_dtors_aux,
which has no line number information.
0x0000000000400450 in deregister_tm_clones ()
Single stepping until exit from function deregister_tm_clones,
which has no line number information.
0x00000000004004d2 in __do_global_dtors_aux ()
Single stepping until exit from function __do_global_dtors_aux,
which has no line number information.
0x00000000004005f4 in _fini ()
Single stepping until exit from function _fini,
which has no line number information.
__run_exit_handlers (status=0, listp=0x3c777b16a8 <__exit_funcs>, run_list_atexit=run_list_atexit@entry=true) at exit.c:78
78 break;
45 while (cur->idx > 0)
82 *listp = cur->next;
83 if (*listp != NULL)
82 *listp = cur->next;
83 if (*listp != NULL)
89 if (run_list_atexit)
90 RUN_HOOK (__libc_atexit, ());
_IO_cleanup () at genops.c:1003
1003 {
1006 int result = _IO_flush_all_lockp (0);
1003 {
1015 _IO_unbuffer_write ();
_IO_unbuffer_write () at genops.c:958
958 if (fp->_lock == NULL || _IO_lock_trylock (*fp->_lock) == 0)
_IO_cleanup () at genops.c:1003
1003 {
1006 int result = _IO_flush_all_lockp (0);
_IO_flush_all_lockp (do_lock=do_lock@entry=0) at genops.c:819
819 {
825 __libc_cleanup_region_start (do_lock, flush_cleanup, 0);
819 {
825 __libc_cleanup_region_start (do_lock, flush_cleanup, 0);
831 fp = (_IO_FILE *) _IO_list_all;
832 while (fp != NULL)
830 last_stamp = _IO_list_all_stamp;
832 while (fp != NULL)
836 _IO_flockfile (fp);
835 if (do_lock)
834 run_fp = fp;
835 if (do_lock)
838 if (((fp->_mode <= 0 && fp->_IO_write_ptr > fp->_IO_write_base)
848 if (do_lock)
852 if (last_stamp != _IO_list_all_stamp)
850 run_fp = NULL;
852 if (last_stamp != _IO_list_all_stamp)
859 fp = fp->_chain;
832 while (fp != NULL)
835 if (do_lock)
834 run_fp = fp;
835 if (do_lock)
838 if (((fp->_mode <= 0 && fp->_IO_write_ptr > fp->_IO_write_base)
848 if (do_lock)
852 if (last_stamp != _IO_list_all_stamp)
850 run_fp = NULL;
852 if (last_stamp != _IO_list_all_stamp)
859 fp = fp->_chain;
832 while (fp != NULL)
835 if (do_lock)
834 run_fp = fp;
835 if (do_lock)
838 if (((fp->_mode <= 0 && fp->_IO_write_ptr > fp->_IO_write_base)
848 if (do_lock)
852 if (last_stamp != _IO_list_all_stamp)
850 run_fp = NULL;
852 if (last_stamp != _IO_list_all_stamp)
859 fp = fp->_chain;
832 while (fp != NULL)
863 if (do_lock)
865 __libc_cleanup_region_end (0);
869 }
_IO_cleanup () at genops.c:1015
1015 _IO_unbuffer_write ();
_IO_unbuffer_write () at genops.c:947
947 for (fp = (_IO_FILE *) _IO_list_all; fp; fp = fp->_chain)
_IO_cleanup () at genops.c:1006
1006 int result = _IO_flush_all_lockp (0);
1015 _IO_unbuffer_write ();
_IO_unbuffer_write () at genops.c:947
947 for (fp = (_IO_FILE *) _IO_list_all; fp; fp = fp->_chain)
949 if (! (fp->_flags & _IO_UNBUFFERED)
983 fp->_mode = -1;
947 for (fp = (_IO_FILE *) _IO_list_all; fp; fp = fp->_chain)
949 if (! (fp->_flags & _IO_UNBUFFERED)
951 || (fp->_flags & _IO_IS_APPENDING))
950 && (! (fp->_flags & _IO_NO_WRITES)
953 && fp->_mode != 0)
983 fp->_mode = -1;
947 for (fp = (_IO_FILE *) _IO_list_all; fp; fp = fp->_chain)
949 if (! (fp->_flags & _IO_UNBUFFERED)
951 || (fp->_flags & _IO_IS_APPENDING))
950 && (! (fp->_flags & _IO_NO_WRITES)
983 fp->_mode = -1;
947 for (fp = (_IO_FILE *) _IO_list_all; fp; fp = fp->_chain)
_IO_cleanup () at genops.c:1018
1018 }
__run_exit_handlers (status=0, listp=<optimized out>, run_list_atexit=run_list_atexit@entry=true) at exit.c:92
92 _exit (status);
__GI__exit (status=status@entry=0) at ../sysdeps/unix/sysv/linux/_exit.c:28
28 {
32 INLINE_SYSCALL (exit_group, 1, status);
34 INLINE_SYSCALL (exit, 1, status);
32 INLINE_SYSCALL (exit_group, 1, status);
[Inferior 1 (process 32305) exited normally]
inferior exited with code: 0
请注意，有时局部变量tmp，src显示为优化。我在x86-64，其中函数参数在寄存器中传递，有时tmp被放置在寄存器 R 中，而在代码中使用它然后gcc想要使用寄存器 R 用于其他内容，tmp的值被覆盖。这表明变量转储的质量取决于编译器生成的调试信息的质量。最近的gcc为C / C ++提供了相当不错的调试信息，我不确定gcc Pascal端口的最新版本或FPC在这里的效果如何。
在Pascal中生成一个测试程序，用调试信息编译它（传递 -g ）并对其进行测试留给读者练习;）
答案 2 :(得分：0)
是的，可以在Pascal程序上使用gdb调试器，前提是您的Pascal编译器提供了DWARF调试信息。如果使用GNU Pascal（即gpc），您希望在调用gpc时传递the -g option。如果您使用Free Pascal，它还accepts the -g option到fpc。
使用调试信息编译Pascal程序后，您需要学习如何使用GNU gdb。您可能需要display，step，next，break，print，frame，cont命令（至{{ 1}}）等等。
答案 3 :(得分：0)
因为每个图形IDE支持开箱即用，所以答案似乎倾向于使用命令行工具，假设你不是IDE。
但如果那没问题.. Lazarus就可以做到。您只需编译，按F7和F8跳过/进入LOC，并在检查器窗口中查看该范围内的所有变量。
另一个IDE是Delphi，但那不是开源/免费的。