Re: [Valgrind-developers] More updates

[Nicholas N. <nj...@ca...>]

On Tue, 22 Oct 2002, Julian Seward wrote:

> Merging more stuff in.  I just did 08-skin-clientreq.

I am a heinous slacker.  Thanks.

> Nick: I spotted the infamous (?) VG_(get_current_tid_1_if_root)
> and specifically this:
>
>    if (0 == vg_tid_currently_in_baseBlock)
>       return 1;     /* root thread */
>
> What's the meaning of the 0 here?  Where is it set?  AFAICS the only
> valid values of vg_tid_currently_in_baseBlock are either 1 .. VG_N_THREADS
> or VG_INVALID_THREADID, so I guess I'm missing something here?

I was probably missing something when I wrote it.  It always felt nasty to
me but I thought it was necessary.  IIRC VG_(get_current_tid) returns 0 in
some circumstances, I can't remember and/or never understood why.  Because
thread #0 is some special reserved thread or something, and thread #1 is
meant to be the root thread, which I thought corresponded to the only
thread for non-threaded programs.  But that may be totally bogus.  Maybe
the #0 being returned was related to the system call wrong-tid bug, I
don't know.

Jeremy, by now you understand Helgrind much better than I, if you think it
should go then please kill it!  You must be getting a fairly good idea of
how little time I spent testing Helgrind.  I just hope that it was quicker
for you to fix the existing code rather than to rewrite it from scratch.

N