On Tue, Oct 18, 2016 at 05:52:00PM +0200, Greg Kurz wrote: > On Tue, 18 Oct 2016 16:31:24 +0100 > "Daniel P. Berrange" <berra...@redhat.com> wrote: > > > On Tue, Oct 18, 2016 at 04:16:46PM +0100, Daniel P. Berrange wrote: > > > On Fri, Oct 14, 2016 at 04:31:01PM -0500, Eric Blake 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. > > > > > > > > > > The current code takes care of turning '/' and '-' characters into > > > > > underscores so that the resulting names are valid C tokens. This is > > > > > enough because these are the only illegal characters that appear in > > > > > a relative path within the QEMU source tree. > > > > > > > > > > Things are different for out of tree builds where the path may contain > > > > > arbitrary character combinations, causing tracetool to generate > > > > > invalid > > > > > names. > > > > > > > > > > > > > > This patch ensures that only letters [A-Za-z], digits [0-9] and > > > > > underscores > > > > > are kept. All other characters are turned into underscores. Also, > > > > > since the > > > > > first character of C symbol names cannot be a digit, an underscore is > > > > > prepended to the group name. > > > > > > > > > > Signed-off-by: Greg Kurz <gr...@kaod.org> > > > > > --- > > > > > scripts/tracetool.py | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > 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? > > > > > > > > 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. > > > > > > This is a mistake on my part - the code was supposed to be stripping > > > off the build directory prefix, leaving only the relative path to the > > > file wrt source directory. The code is simply wrong as is. > > > > Ah ha, I realize what the issue is. > > > > Currently in git master we have multiple trace-events files and we merge > > them into a single trace-events-all file, then generate the various > > bits we need. This trace-events-all file is naturally in the build > > dir, not the source dir > > > > In my trace events patch build refactor series though, I have stopped > > creating trace-events-all, and we instead generate bits directly from > > the trace-events files in source dir. So this problem only appeared > > because we've only merge part of my series into master. > > > > Heh commit 80dd5c4918ab then makes sense in this scenario, except perhaps > the nit about --group in the changelog. > > > IOW, I think Greg's proposed fix is fine as a workaround - once the > > rest of my patches merge, build dir should not pollute this at all. > > > > I have two other patches ready to fix the current situation: > - one using os.getcwd() to guess the build directory > - one implementing --group as mentioned in my other mail > > But the one that filters unwanted characters is a less intrusive > workaround.
If Dan's patches will eliminate the issue then we can take a workaround. Any more comments about Greg's patch before I merge it? Stefan
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