RFR (S): Supports statically linking TSAN runtime into the launcher with Clang

[Arthur Eubanks]

This looks promising, let me do some testing.

Regarding the size of the write in native code, we should probably not
depend on the exact size, since that's not what we care about.

*From: *Jean Christophe Beyler <jcbeyler at google.com>
*Date: *Tue, May 14, 2019 at 10:31 AM
*To: *Man Cao
*Cc: * <tsan-dev at openjdk.java.net>

LGTM, I am curious about the clang write of size 1 issue but I suggest we
> push that to post this submission; that way we all have the info to build
> and test,
> Jc
>
> *From: *Man Cao <manc at google.com>
> *Date: *Mon, May 13, 2019 at 10:15 PM
> *To: * <tsan-dev at openjdk.java.net>
>
> FYI, I used the pre-built LLVM 8.0.0 for Ubuntu 18.04 from here:
> > http://releases.llvm.org/download.html#8.0.0
> >
> > I will also update the wiki page if everyone likes this workaround.
> >
> > -Man
> >
> >
> > *From: *Man Cao <manc at google.com>
> > *Date: *Mon, May 13, 2019 at 10:08 PM
> > *To: * <tsan-dev at openjdk.java.net>
> >
> > Hi all,
> > >
> > > Can I have reviews for this patch that hopefully will unblock us from
> the
> > > libtsan.so's version issue?
> > > https://cr.openjdk.java.net/~manc/tsan20190513/webrev.00/
> > >
> > > This is a workaround for the version issue with libtsan.so in GCC. If
> we
> > > build the JDK with Clang, we will have a newer version of the TSAN
> > runtime
> > > statically linked into the launcher:
> > > $ nm images/jdk/bin/java | grep tsan_symbolize
> > > 000000000048e640 W __tsan_symbolize_external
> > > 000000000048e650 W __tsan_symbolize_external_ex
> > >
> > > In the long term, Java TSAN will still work with GCC, but stack trace
> > > symbolization will be broken until OpenJDK can be built with GCC9,
> which
> > > contains the new version of libtsan.so that we need.
> > > Also need to write distinct values to the global variable in
> > > libAbstractNativeLoop.cpp, otherwise some optimization in Clang could
> > treat
> > > the variable as constant, and TSAN reports "Write of size 1" instead of
> > > "size 4".
> > >
> > > I have tested this with both LLVM 8.0.0 and GCC.
> > >
> > > -Man
> > >
> >
>
>
> --
>
> Thanks,
> Jc
>