Re: [PATCH] Remove unnecessary get_current_frame calls from infrun.c

[Tom Tromey <tom@tromey.com>]

>>>>> "Simon" == Simon Marchi <simark@simark.ca> writes:

>> -	  /* Re-fetch current thread's frame in case that invalidated
>> -	     the frame cache.  */
>> -	  frame = get_current_frame ();
>> -	  gdbarch = get_frame_arch (frame);

Simon> For `frame` I agree, I think we can remove it.  But I'm wondering about
Simon> `gdbarch`.  Before we had `frame_info_ptr`, even if `frame` got
Simon> invalidated, it didn't seem necessary to reset `gdbarch`.  Are there
Simon> cases where you would get a different value for `gdbarch` as it
Simon> currently holds?  I can't think of any.  I'm leaning towards saying that
Simon> this is fine.

I think the main danger in this patch is if the current comments are
wrong -- that is, when it is referring to something reinitializing the
frame cache, is that correct?  Or could the inferior be restarted
somewhere in here, resulting in a different current frame?  In the
latter case get_current_frame definitely has to be called again, the old
frame may not even exist.

I don't think it's possible for the gdbarch to change mid-frame, only
between frames.  This capability has been desired a few times (x86
boot-up apparently switches modes or something), but patches have never
been supplied.

So, I tend to think not resetting gdbarch is fine.

Tom