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PING
I added some comment and changed the order of evaluation a bit, hoping to reduce the performance impact on normal debugging. And I ran the testsuites, before and after.
Modified patch is attached -- is this OK with you guys? Mark, can you confirm that it fixes your original bug?
Thx again, Michael
On Mon, May 11, 2009 at 15:07, Hui Zhu<teawater@gmail.com> wrote:PING
On Wed, May 6, 2009 at 15:23, Hui Zhu <teawater@gmail.com> wrote:Hi Michael,
Like the prev patch I send to you, this issue still affect cvs-head and the patch can fix it. Please help me review it.
The attachment is the new patch follow cvs-head.
2009-05-06 Hui Zhu <teawater@gmail.com>
* infrun.c (handle_inferior_event): Check frame_id when check range in reverse debug mode.
Thanks, Hui
On Sat, Mar 21, 2009 at 16:52, Hui Zhu <teawater@gmail.com> wrote:Hi,
This patch is for bug report by Marc in http://sourceware.org/ml/gdb/2009-03/msg00127.html.
This bug in "handle_inferior_event" deal with recursion function tail in reverse debug. infrun: infwait_normal_state infrun: TARGET_WAITKIND_STOPPED infrun: stop_pc = 0x8048457 infrun: stepping inside range [0x8048457-0x804845a] infrun: stop_stepping factorial (x=4) at b.cc:5
Inferior already step into another frame. But because this is a recursion function call, And 0x8048457 is in ecs->event_thread->step_range_start and ecs->event_thread->step_range_start.
So gdb run in:
if (stop_pc >= ecs->event_thread->step_range_start && stop_pc < ecs->event_thread->step_range_end) {
This code is in front of: if (!frame_id_eq (get_frame_id (get_current_frame ()), ecs->event_thread->step_frame_id) && (frame_id_eq (frame_unwind_id (get_current_frame ()), ecs->event_thread->step_frame_id) || execution_direction == EXEC_REVERSE))
So gdb check range without check frame_id.
So I make a patch to check frame_id when check range in reverse debug mode.
2008-03-21 Hui Zhu <teawater@gmail.com>
* infrun.c (handle_inferior_event): Check frame_id when check range in reverse debug mode.
Actually, there is another thing, when gdb begin reverse-debug, it's range is: 8048439: 8b 45 08 mov 0x8(%ebp),%eax 804843c: 83 e8 01 sub $0x1,%eax 804843f: 89 04 24 mov %eax,(%esp) 8048442: e8 dd ff ff ff call 8048424 <_Z9factoriali> 8048447: 0f af 45 08 imul 0x8(%ebp),%eax 804844b: 89 45 fc mov %eax,-0x4(%ebp) Why is changed to infrun: stepping inside range [0x8048457-0x804845a]? That is because when inferior step at: 8048458: c3 ret In this address, $ebp is same with high level function and this function is factorial too. So the gdb can't found inferior step into another frame. It will run to: ecs->event_thread->step_range_start = stop_pc_sal.pc; ecs->event_thread->step_range_end = stop_pc_sal.end; ecs->event_thread->step_frame_id = get_frame_id (get_current_frame ()); ecs->event_thread->current_line = stop_pc_sal.line; ecs->event_thread->current_symtab = stop_pc_sal.symtab;
if (debug_infrun) fprintf_unfiltered (gdb_stdlog, "infrun: keep going\n"); keep_going (ecs); } So ecs->event_thread->step_range_start and ecs->event_thread->step_range_end.
I don't find that it affect the reverse debug or something. So I didn't fix it.
Thanks, Hui
2009-06-14 Hui Zhu <teawater@gmail.com> Michael Snyder <msnyder@vmware.com> * infrun.c (handle_inferior_event): Improve reverse stepping through function epilogue. Index: infrun.c =================================================================== RCS file: /cvs/src/src/gdb/infrun.c,v retrieving revision 1.387 diff -u -p -r1.387 infrun.c --- infrun.c 11 Jun 2009 11:57:46 -0000 1.387 +++ infrun.c 15 Jun 2009 00:45:17 -0000 @@ -3623,9 +3623,17 @@ infrun: not switching back to stepped th Note that step_range_end is the address of the first instruction beyond the step range, and NOT the address of the last instruction - within it! */ + within it! + + Note also that during reverse execution, we may be stepping + through a function epilogue and therefore must detect when + the current-frame changes in the middle of a line. */ + if (stop_pc >= ecs->event_thread->step_range_start - && stop_pc < ecs->event_thread->step_range_end) + && stop_pc < ecs->event_thread->step_range_end + && (execution_direction != EXEC_REVERSE + || frame_id_eq (get_frame_id (get_current_frame ()), + ecs->event_thread->step_frame_id))) { if (debug_infrun) fprintf_unfiltered (gdb_stdlog, "infrun: stepping inside range [0x%s-0x%s]\n",
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