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

Magnus Ihse Bursie magnus.ihse.bursie at oracle.com
Wed Nov 21 11:44:00 UTC 2018



On 2018-11-20 18:50, Volker Simonis wrote:
> 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 to play 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://bugs.openjdk.java.net/browse/JDK-8204541
>>>
>>> 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)?
In configure (where, ideally, all version checks should be made), 
there's the TOOLCHAIN_CHECK_COMPILER_VERSION function, which supports
#   IF_AT_LEAST:   block to run if the compiler is at least this version 
(>=)
#   IF_OLDER_THAN:   block to run if the compiler is older than this 
version (<)
for normal, dot-separated version number schemes.

/Magnus

>
> 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] https://bugs.openjdk.java.net/browse/JDK-8202322
>
>> ..Thomas
>>
>>> Best Regards
>>>
>>> Adam Farley
>>> IBM Runtimes
>>>
>>>
>>> "Thomas Stüfe" <thomas.stuefe at gmail.com> wrote on 20/11/2018 16:44:07:
>>>
>>>> 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.
>>>>> https://urldefense.proofpoint.com/v2/url?
>>>> 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 19/11/2018 18:11:34:
>>>>>
>>>>>> 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



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