RFR(xs): 8171408: [aix] TOC overflow when linking the gtest libjvm.so

Erik Joelsson erik.joelsson at oracle.com
Tue Dec 20 08:17:56 UTC 2016


I understand why you want to filter out the -qpic flag from the general 
JVM_CFLAGS, but that kind of logic is brittle so we try to avoid it 
unless absolutely necessary. I prefer to just rely on the tools treating 
command line options as the last one takes precedence. I assume the AIX 
compiler behaves that way too and that a -qpic=large will override a 
-qpic earlier on the command line. We have consciously designed 
SetupNativeCompilation to add all the *FLAGS in the order of most 
specific flags last for this reason.

So, could you try removing the filtering and see if it still works?


On 2016-12-18 13:50, Thomas Stüfe wrote:
> Hi all,
> please take a look at this small fix. In short, on AIX when linking the
> gtest version of libjvm.so, the TOC overflows.
> So the gtest libjvm.so must be linked with -bbigtoc, in contrast to the
> regular libjvm.so, which has no problems and can keep using a small TOC.
> Also, I compile all gtest objects with -qpic=large. Note that this only
> affects the gtest objects. The regular objects - which the gtest libjvm.so
> shares with the regular libjvm.so - I left at -qpic[=small]. This means we
> pay a bit of a performance overhead in the gtest libjvm.so but leave the
> regular libjvm.so at its optimal linker settings.
> Issue:
> https://bugs.openjdk.java.net/browse/JDK-8171408
> Webrev:
> http://cr.openjdk.java.net/~stuefe/webrevs/8171408-aix-TOC-overflow-when-linking-the-gtest-libjvm/webrev.00/
> (Hope the webrev link works, the webserver is still down).
> Kind Regards, Thomas

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