RFR: JDK-8214063: OpenJDK will not build on AIX while using the xlc 13.1 compiler

Wed Nov 21 16:45:06 UTC 2018

Hi Volker,

Will do some digging and see if I can figure out the cause of the 
compilation problem.

Also, I don't have a record of the original error after we added the 
JNIEXPORT/JNIIMPORT fix in, so I've got a build running now to reproduce 
it.

Best Regards

Adam Farley 
IBM Runtimes

Volker Simonis <volker.simonis at gmail.com> wrote on 21/11/2018 14:07:07:

> From: Volker Simonis <volker.simonis at gmail.com>
> To: adam.farley at uk.ibm.com
> Cc: Java Core Libs <core-libs-dev at openjdk.java.net>, "Stuefe, 
> Thomas" <thomas.stuefe at gmail.com>
> Date: 21/11/2018 14:07
> Subject: Re: RFR: JDK-8214063: OpenJDK will not build on AIX while 
> using the xlc 13.1 compiler
> 
> On Wed, Nov 21, 2018 at 1:46 PM Adam Farley8 <adam.farley at uk.ibm.com> 
wrote:
> >
> > Hi Volker,
> >
> > The NativeImageBuffer.cpp changes are best explained by the full text 
of
> > the referenced GitHub Pull Request, copied here for simplicity:
> >
> > -----------------------------------------
> > Define JNIEXPORT and JNIIMPORT for xlc version 13.1 or newer. Without 
this,
> > almost no symbols are exported from shared libraries due to use of
> > -qvisibility=hidden as specified in make/lib/LibCommon.gmk. The 
symptoms
> > are reported in eclipse/openj9#2468.
> >
> > Unfortunately, this encounters a bug in xlc: it fails to parse what 
seems
> > to be reasonable code.
> 
> Sorry, but I don't see how this answers my question.
> 
> 1. Which "reasonable code" does xlc fails to parse. A stand-alone
> example would be nice.
> 
> 2. Have you reported this as bug to the xlc developers? What did they 
say?
> 
> 3. "jdk_internal_jimage_NativeImageBuffer.h" doesn't seem to be
> special. It's a plain, generated JNI header file as generated by
> 'javah' or 'javac -h'. If XLC 13 has problems parsing it, there should
> be much more places which need fixing. So what's special about
> "jdk_internal_jimage_NativeImageBuffer.h".
> 
> In the referenced pull request
> (INVALID URI REMOVED
> 
u=https-3A__github.com_eclipse_openj9_issues_2468&d=DwIFaQ&c=jf_iaSHvJObTbx-
> siA1ZOg&r=P5m8KWUXJf-
> 
CeVJc0hDGD9AQ2LkcXDC0PMV9ntVw5Ho&m=sgfFd6mB1EYM4nOM89rgFFzUyX7B21XbckIY7L0kUNU&s=TJ-4nr8ikZKImwDygirRTxLybsnQWBN71nEZCwZ59NQ&e=
> ) I can only see linker
> errors (and no compiler errors). The linker errors are for both
> libjsig and libjava. They are related to the symbol ".sigaction" in
> jsig.o and I don't see how this should be related to
> NativeImageBuffer.cpp or "jdk_internal_jimage_NativeImageBuffer.h".
> NativeImageBuffer.cpp is only used to create libjimage and not related
> in any way to libjsig or libjava.
> 
> It seems wired to do the change to NativeImageBuffer.cpp which you've
> proposed without understanding the real cause of the problem.
> 
> Regards,
> Volker
> 
> > A workaround is required in just one place:
> > src/java.base/share/native/libjimage/NativeImageBuffer.cpp.
> > -----------------------------------------
> >
> > Best Regards
> >
> > Adam Farley
> > IBM Runtimes
> >
> >
> > Volker Simonis <volker.simonis at gmail.com> wrote on 20/11/2018 
17:50:41:
> >
> > > From: Volker Simonis <volker.simonis at gmail.com>
> > > To: "Stuefe, Thomas" <thomas.stuefe at gmail.com>
> > > Cc: adam.farley at uk.ibm.com, Java Core Libs <core-libs-
> dev at openjdk.java.net>
> > > Date: 20/11/2018 17:59
> > > Subject: Re: RFR: JDK-8214063: OpenJDK will not build on AIX while
> > > using the xlc 13.1 compiler
> > >
> > > On Tue, Nov 20, 2018 at 6:15 PM Thomas Stüfe 
> <thomas.stuefe at gmail.com> wrote:
> > > >
> > > > On Tue, Nov 20, 2018 at 6:12 PM Adam Farley8 
> <adam.farley at uk.ibm.com> wrote:
> > > > >
> > > > > Heya Tom,
> > > > >
> > > > > "In JDK11 and JDK12, source files are compiled with -
> qvisibility=hidden
> > > > > when using xlc version other than 12.1. That doesn't seem toplay 
well
> > > > > with link option -bexpall. "
> > > > >
> > > > > Found that buried in one of the associated Git issues. It 
appears that
> > > > > it's OpenJDK's use of that option that's causing the problem, 
though
> > > > > I couldn't speculate as to why it was added in the first place.
> > > > >
> > > > > I see this has also been noted in https://
> > > urldefense.proofpoint.com/v2/url?
> > > 
> 
u=https-3A__bugs.openjdk.java.net_browse_JDK-2D8204541&d=DwIFaQ&c=jf_iaSHvJObTbx-
> > > siA1ZOg&r=P5m8KWUXJf-
> > > 
> 
CeVJc0hDGD9AQ2LkcXDC0PMV9ntVw5Ho&m=SD6UdjysISJRBlWUm8pEzF5lRZ5opfbrKzEh_jrOras&s=5qDEdIfg8qZ-
> > > vCglsZ9qNDTEPMnCkj-mVPVah6eEDLE&e=
> > > > >
> > > > > Does that answer your question?
> > > > >
> > > >
> > > > Yes, Thank you. Odd. Will have to do archeology on that one.
> > > >
> > >
> > > No I begin to understand the problem as well :)
> > >
> > > It was actually change "8202322: AIX: symbol visibility flags not
> > > support on xlc 12.1" [1] which introduced "-qvisibility=hidden" for
> > > XLC version not equal to 12.1. That's kind of a weak check and I
> > > suppose nobody has ever tested this change with an XLC version other
> > > than 12.1 (until you came along :). Maybe that check should be a 
more
> > > precisly check for >= 13.1 (but I know such version checks are hard 
to
> > > do in Makefile syntax)?
> > >
> > > The thing I don't understand about your patch (the changes in
> > > "jni_md.h" look good although I haven't tested them) is why you need
> > > the extra changes in NativeImageBuffer.cpp?
> > > "jdk_internal_jimage_NativeImageBuffer.h" is a plain, generated JNI
> > > header file. If XLC 13 has problems to parse it, there should be 
much
> > > more places which need fixing. I think that part of your change 
needs
> > > a closer evaluation.
> > >
> > > Thank you and best regards,
> > > Volker
> > >
> > > [1] INVALID URI REMOVED
> > > 
> 
u=https-3A__bugs.openjdk.java.net_browse_JDK-2D8202322&d=DwIFaQ&c=jf_iaSHvJObTbx-
> > > siA1ZOg&r=P5m8KWUXJf-
> > > 
> 
CeVJc0hDGD9AQ2LkcXDC0PMV9ntVw5Ho&m=SD6UdjysISJRBlWUm8pEzF5lRZ5opfbrKzEh_jrOras&s=JAEK6rePGMPinZzOquHBzj5oc7vA3kaFt9x0WIIUzvk&e=
> > >
> > > > ..Thomas
> > > >
> > > > > Best Regards
> > > > >
> > > > > Adam Farley
> > > > > IBM Runtimes
> > > > >
> > > > >
> > > > > "Thomas Stüfe" <thomas.stuefe at gmail.com> wrote on 
20/11/201816:44:07:
> > > > >
> > > > > > From: "Thomas Stüfe" <thomas.stuefe at gmail.com>
> > > > > > To: Adam Farley8 <adam.farley at uk.ibm.com>
> > > > > > Cc: Java Core Libs <core-libs-dev at openjdk.java.net>
> > > > > > Date: 20/11/2018 16:48
> > > > > > Subject: Re: RFR: JDK-8214063: OpenJDK will not build on AIX 
while
> > > > > > using the xlc 13.1 compiler
> > > > > >
> > > > > > Hi Adam,
> > > > > >
> > > > > > On Tue, Nov 20, 2018 at 5:12 PM Adam Farley8
> > > <adam.farley at uk.ibm.com> wrote:
> > > > > > >
> > > > > > > Hi Tom,
> > > > > > >
> > > > > > > Sounds reasonable. I've added a webex to the bug, and here's 
a
> > > > > > link to the bug.
> > > > > > >
> > > > > > > INVALID URI REMOVED
> > > > > >
> > > 
> 
u=https-3A__bugs.openjdk.java.net_browse_JDK-2D8214063&d=DwIFaQ&c=jf_iaSHvJObTbx-
> > > > > > siA1ZOg&r=P5m8KWUXJf-
> > > > > >
> > > 
> 
CeVJc0hDGD9AQ2LkcXDC0PMV9ntVw5Ho&m=z8YYwBXEfN7UtX1suPjpp9CZSHf8v0GrIMK3XGIC9VY&s=81TP9mIjhYD2Hmt8g7p2EHWRZXgiep21hxKLYRU7zIQ&e=
> > > > > > >
> > > > > > > This patch is required because otherwise, when building on 
AIX
> > > > > > using xlc 3.1,
> > > > > > > the build fails with this error:
> > > > > > >
> > > > > > > "Visibility is not allowed on a reference to an imported 
symbol."
> > > > > > >
> > > > > > > We believe this is caused by JNIEXPORT and JNIIMPORT not 
being
> > > > > > defined. Without
> > > > > > > this, almost no symbols are exported from shared libraries
> > > due to use of
> > > > > > > -qvisibility=hidden as specified in make/lib/LibCommon.gmk.
> > > > > >
> > > > > > Yes but what I try to understand is why does this happen now 
with
> > > > > > xlc13? Did xlc change the rules for -qvisibility from v12 to 
v13 ?
> > > > > > That would be quite a break in backward compatibility.
> > > > > >
> > > > > > >
> > > > > > > For convenience, here's a summary of the diffs:
> > > > > > >
> > > > > > > --------------------------------------
> > > > > > > File 1 of 2) src/java.base/share/native/libjimage/
> > > NativeImageBuffer.cpp
> > > > > > >
> > > > > > >  #include "osSupport.hpp"
> > > > > > >
> > > > > > > +#if defined(__xlC__) && (__xlC__ >= 0x0d01)
> > > > > > > +/*
> > > > > > > + * Version 13.1.3 of xlc seems to have trouble parsing the
> > > `__attribute__`
> > > > > > > + * annotation in the generated header file we're about to
> > > > > > include. Repeating
> > > > > > > + * the forward declaration (without the braces) here avoids
> > > the diagnostic:
> > > > > > > + *   1540-0040 (S) The text "void" is unexpected. 
"visibility"
> > > > > > may be undeclared or ambiguous.
> > > > > > > + */
> > > > > > > +extern "C" JNIEXPORT jobject JNICALL
> > > > > > Java_jdk_internal_jimage_NativeImageBuffer_getNativeMap(JNIEnv 
*,
> > > > > > jclass, jstring);
> > > > > > > +#endif
> > > > > > > +
> > > > > > > #include "jdk_internal_jimage_NativeImageBuffer.h"
> > > > > > > --------------------------------------
> > > > > > > File 2 of 2) src/java.base/unix/native/include/jni_md.h
> > > > > > >
> > > > > > >      #define JNIIMPORT 
__attribute__((visibility("default")))
> > > > > > >   #endif
> > > > > > > +#elif defined(__xlC__) && (__xlC__ >= 0x0d01) /* xlc 
version 13.1
> > > > > > or better required */
> > > > > > > +  #define JNIEXPORT __attribute__((visibility("default")))
> > > > > > > +  #define JNIIMPORT __attribute__((visibility("default")))
> > > > > > > #else
> > > > > > >   #define JNIEXPORT
> > > > > > > --------------------------------------
> > > > > > >
> > > > > >
> > > > > > Thank you.
> > > > > >
> > > > > > Cheers, Thomas
> > > > > >
> > > > > > > Best Regards
> > > > > > >
> > > > > > > Adam Farley
> > > > > > > IBM Runtimes
> > > > > > >
> > > > > > >
> > > > > > > "Thomas Stüfe" <thomas.stuefe at gmail.com> wrote on 19/11/
> 201818:11:34:
> > > > > > >
> > > > > > > > From: "Thomas Stüfe" <thomas.stuefe at gmail.com>
> > > > > > > > To: Adam Farley8 <adam.farley at uk.ibm.com>
> > > > > > > > Cc: Java Core Libs <core-libs-dev at openjdk.java.net>
> > > > > > > > Date: 19/11/2018 18:12
> > > > > > > > Subject: Re: RFR: JDK-8214063: OpenJDK will not build 
> on AIX while
> > > > > > > > using the xlc 13.1 compiler
> > > > > > > >
> > > > > > > > Hi Adam,
> > > > > > > >
> > > > > > > > could you please include link to the JBS issue and either
> > > link to the
> > > > > > > > patch/webrev or link to the webrev, or at the very 
> least the patch
> > > > > > > > verbatim?
> > > > > > > >
> > > > > > > > As for the issue itself: could you please elaborate why 
this
> > > > > > fails with xlc13?
> > > > > > > >
> > > > > > > > Also, a real patch would be helpful instead here of 
> yet another link
> > > > > > > > to some J9 issue. We are really strapped for manpower and
> > > the AIX port
> > > > > > > > eats up enough time as it is.
> > > > > > > >
> > > > > > > > Thanks, Thomas
> > > > > > > >
> > > > > > > > On Mon, Nov 19, 2018 at 6:28 PM Adam Farley8
> > > > > > <adam.farley at uk.ibm.com> wrote:
> > > > > > > > >
> > > > > > > > > Hi All
> > > > > > > > >
> > > > > > > > > Both the problem and the solution appear straight-
> forward enough.
> > > > > > > > >
> > > > > > > > > Details included in the bug description.
> > > > > > > > >
> > > > > > > > > Thoughts and opinions welcome.
> > > > > > > > >
> > > > > > > > > Best Regards
> > > > > > > > >
> > > > > > > > > Adam Farley
> > > > > > > > > IBM Runtimes
> > > > > > > > >
> > > > > > > > > Unless stated otherwise above:
> > > > > > > > > IBM United Kingdom Limited - Registered in England and
> > > Wales with number
> > > > > > > > > 741598.
> > > > > > > > > Registered office: PO Box 41, North Harbour, Portsmouth,
> > > > > > Hampshire PO6 3AU
> > > > > > > >
> > > > > > >
> > > > > > > Unless stated otherwise above:
> > > > > > > IBM United Kingdom Limited - Registered in England and Wales 
with
> > > > > > number 741598.
> > > > > > > Registered office: PO Box 41, North Harbour, Portsmouth,
> > > Hampshire PO6 3AU
> > > > > >
> > > > >
> > > > > Unless stated otherwise above:
> > > > > IBM United Kingdom Limited - Registered in England and Wales
> > > with number 741598.
> > > > > Registered office: PO Box 41, North Harbour, Portsmouth, 
> Hampshire PO6 3AU
> > >
> >
> > Unless stated otherwise above:
> > IBM United Kingdom Limited - Registered in England and Wales with 
> number 741598.
> > Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 
3AU
> 

Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU