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problem debugging assembler functions
- From: Vladimir Prus <ghost at cs dot msu dot su>
- To: gdb at sources dot redhat dot com
- Date: Tue, 14 Jun 2005 13:21:53 +0400
- Subject: problem debugging assembler functions
Hello,
I'm trying to port gdb to a new architecture (with it's own compiler), and
run into problems with assembler functions. I can successfully step into
an assembler function, but when I run "step", instead of moving to the
next instruction, gdb sets breakpoint at return address and continues.
Looking at the code, I see this (in infrun.c)
Line 2285:
if (frame_id_eq (frame_unwind_id (get_current_frame ()), step_frame_id))
{
......
}
Line 2428:
if (step_over_calls == STEP_OVER_UNDEBUGGABLE
&& ecs->stop_func_name == NULL)
{
/* The inferior just stepped into, or returned to, an
undebuggable function (where there is no symbol, not even a
minimal symbol, corresponding to the address where the
inferior stopped).
*/
........
insert_step_resume_breakpoint_at_frame (
get_prev_frame (get_current_frame ()));
}
The condition is the second code block is taken and breakpoint is indeed
set. I have two questions:
1. Is "just stepped into ... function" comment accurate? I think that all
cases of steppin into function are handled by the previous
if (frame_id_eq (frame_unwind_id (get_current_frame ()), step_frame_id)) {}
condition, and all code paths inside that condition end with return. So, the
second code block is not executed when we've just stepped into a function.
Is the code intended to handle only the case when we've *returned* to
undebuggable function?
2. In my case, no function names for assembler modules are present in debug
info, but line information is there, so the function is debuggable. Is
there a way to check of line info in condition, not for function name?
Thanks in advance,
Volodya