[RFA] improved handling of shared lib calls (reverse 2/2)

[Michael Snyder]

And now this one?

Michael Snyder wrote:
> Now how about this one?
> 
> Michael Snyder wrote:
>> This change depends on the previous one (epilogue unwinder for i386,
>> http://sourceware.org/ml/gdb-patches/2009-07/msg00099.html).
>>
>> With the frame unwinder working properly, we can remove the
>> special case code in the test for "check for subroutine call"
>> in handle_inferior_event.
>>
>> Of course that reveals some hidden problems with shared library
>> calls, so this patch also addresses those.
>>
>> Michael
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>> 2009-07-03  Michael Snyder  <msnyder@vmware.com>
>>
>> 	* infrun.c (handle_inferior_event): Remove an execution_direction
>> 	check in the "check for subroutine calls" test, and add some 
>> 	additional handling for reverse-stepping through shared libraries.
>>
>> Index: infrun.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/infrun.c,v
>> retrieving revision 1.400
>> diff -u -p -r1.400 infrun.c
>> --- infrun.c	2 Jul 2009 17:21:06 -0000	1.400
>> +++ infrun.c	4 Jul 2009 00:27:53 -0000
>> @@ -3776,9 +3776,8 @@ infrun: not switching back to stepped th
>>       previous frame must have valid frame IDs.  */
>>    if (!frame_id_eq (get_stack_frame_id (frame),
>>  		    ecs->event_thread->step_stack_frame_id)
>> -      && (frame_id_eq (frame_unwind_caller_id (frame),
>> -		       ecs->event_thread->step_stack_frame_id)
>> -	  || execution_direction == EXEC_REVERSE))
>> +      && frame_id_eq (frame_unwind_caller_id (frame),
>> +		      ecs->event_thread->step_stack_frame_id))
>>      {
>>        CORE_ADDR real_stop_pc;
>>  
>> @@ -3806,6 +3805,7 @@ infrun: not switching back to stepped th
>>        /* Reverse stepping through solib trampolines.  */
>>  
>>        if (execution_direction == EXEC_REVERSE
>> +	  && ecs->event_thread->step_over_calls != STEP_OVER_NONE
>>  	  && (gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc)
>>  	      || (ecs->stop_func_start == 0
>>  		  && in_solib_dynsym_resolve_code (stop_pc))))
>> @@ -3923,6 +3923,38 @@ infrun: not switching back to stepped th
>>        return;
>>      }
>>  
>> +  /* Reverse stepping through solib trampolines.  */
>> +
>> +  if (execution_direction == EXEC_REVERSE
>> +      && ecs->event_thread->step_over_calls != STEP_OVER_NONE)
>> +    {
>> +      if (gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc)
>> +	  || (ecs->stop_func_start == 0
>> +	      && in_solib_dynsym_resolve_code (stop_pc)))
>> +	{
>> +	  /* Any solib trampoline code can be handled in reverse
>> +	     by simply continuing to single-step.  We have already
>> +	     executed the solib function (backwards), and a few 
>> +	     steps will take us back through the trampoline to the
>> +	     caller.  */
>> +	  keep_going (ecs);
>> +	  return;
>> +	}
>> +      else if (in_solib_dynsym_resolve_code (stop_pc))
>> +	{
>> +	  /* Stepped backward into the solib dynsym resolver.
>> +	     Set a breakpoint at its start and continue, then
>> +	     one more step will take us out.  */
>> +	  struct symtab_and_line sr_sal;
>> +	  init_sal (&sr_sal);
>> +	  sr_sal.pc = ecs->stop_func_start;
>> +	  insert_step_resume_breakpoint_at_sal (gdbarch, 
>> +						sr_sal, null_frame_id);
>> +	  keep_going (ecs);
>> +	  return;
>> +	}
>> +    }
>> +
>>    /* If we're in the return path from a shared library trampoline,
>>       we want to proceed through the trampoline when stepping.  */
>>    if (gdbarch_in_solib_return_trampoline (gdbarch,
> 
>