On 14 October 2016 at 23:06, Greg Kurz <gr...@kaod.org> wrote: > On Fri, 14 Oct 2016 16:31:01 -0500 > Eric Blake <ebl...@redhat.com> wrote: > >> On 10/14/2016 04:26 PM, Greg Kurz wrote: >> > Since commit "80dd5c4918ab trace: introduce a formal group name for trace >> > events", tracetool generates C variable names and macro definitions out >> > of the path to the trace-events-all file.
>> > diff --git a/scripts/tracetool.py b/scripts/tracetool.py >> > index 629b2593c846..b81b834db924 100755 >> > --- a/scripts/tracetool.py >> > +++ b/scripts/tracetool.py >> > @@ -70,7 +70,7 @@ def make_group_name(filename): >> > >> > if dirname == "": >> > return "common" >> > - return re.sub(r"/|-", "_", dirname) >> > + return "_" + re.sub(r"[^\w]", "_", dirname) >> >> This STILL doesn't solve the complaint that the build is now dependent >> on the location. Why can't we STRIP off any prefix prior to the in-tree >> portion of the naming that we know is sane, instead of munging the >> prefix but in the process creating source code that generates with >> different lengths? >> > > Heh, because the complaint was about the build break :) > >> Ideally, compiling twice, once in directory 'a', and the second time in >> directory 'aaaaaaaaaaaaaaaaaaaaaaaaaaaa', should not make a noticeable >> difference in the final size of the executable due to the difference in >> lengths of the debugging symbols used to record the longer name of the >> second directory being encoded into lots of macro names. >> > > You're right. I'm okay to look for a way to fix the symbol variable size > issue, but I think this patch still makes sense as it makes tracetool > less fragile in case we add a directory with an illegal character to > the QEMU tree... and it fixes annoying build breaks (Paolo also hit > this and asked to revert 80dd5c4918ab in another mail). I agree with Eric that we should just not be putting the build directory name in these variables -- this looks like it's simply a bug to me, and we should fix it. I think the chances of us adding a directory to the QEMU tree itself with a silly name are quite low (not least because if you do that then you get a handy build failure to tell you not to do that ;-)) thanks -- PMM
