RFR : 8202322: AIX: symbol visibility flags not support on xlc 12.1

Langer, Christoph christoph.langer at sap.com
Thu Jun 7 11:43:54 UTC 2018 

Hi Ichiroh,

your proposal seems to make sense. I have created a bug for this: https://bugs.openjdk.java.net/browse/JDK-8204541

Can you please generate a webrev (referencing this bug, -c option of webrev.ksh) and mail it over to me. Then I'll upload it and you can post an official RFR mail.

Best regards
Christoph

> -----Original Message-----
> From: Ichiroh Takiguchi [mailto:takiguc at linux.vnet.ibm.com]
> Sent: Dienstag, 5. Juni 2018 08:59
> To: Baesken, Matthias <matthias.baesken at sap.com>
> Cc: Langer, Christoph <christoph.langer at sap.com>; 'build-
> dev at openjdk.java.net' <build-dev at openjdk.java.net>; ppc-aix-port-
> dev at openjdk.java.net; core-libs-dev at openjdk.java.net; Lindenmaier,
> Goetz <goetz.lindenmaier at sap.com>
> Subject: RE: RFR : 8202322: AIX: symbol visibility flags not support on xlc 12.1
> 
> Hello Matthias and Christoph.
> Thank you for your explanations.
> 
> I did not have enough knowledge about "visibility".
> 
> I created following patches.
> 
> ================================
> diff -r 02934b0d661b
> src/java.base/share/native/libjimage/NativeImageBuffer.cpp
> --- a/src/java.base/share/native/libjimage/NativeImageBuffer.cpp	Wed
> May
> 30 14:46:28 2018 +0200
> +++ b/src/java.base/share/native/libjimage/NativeImageBuffer.cpp	Tue Jun
> 05 12:10:41 2018 +0900
> @@ -39,7 +39,9 @@
>   #include "imageFile.hpp"
>   #include "inttypes.hpp"
>   #include "jimage.hpp"
> +#if !defined(_AIX)
>   #include "osSupport.hpp"
> +#endif
> 
>   #include "jdk_internal_jimage_NativeImageBuffer.h"
> 
> diff -r 02934b0d661b src/java.base/unix/native/include/jni_md.h
> --- a/src/java.base/unix/native/include/jni_md.h	Wed May 30 14:46:28
> 2018 +0200
> +++ b/src/java.base/unix/native/include/jni_md.h	Tue Jun 05 12:10:41
> 2018 +0900
> @@ -29,7 +29,8 @@
>   #ifndef __has_attribute
>     #define __has_attribute(x) 0
>   #endif
> -#if (defined(__GNUC__) && ((__GNUC__ > 4) || (__GNUC__ == 4) &&
> (__GNUC_MINOR__ > 2))) || __has_attribute(visibility)
> +#if (defined(__GNUC__) && ((__GNUC__ > 4) || (__GNUC__ == 4) &&
> (__GNUC_MINOR__ > 2))) || __has_attribute(visibility) \
> +    || (defined(_AIX) && (defined(__xlC__) && (__xlC__ >= 0xD01)))
>     #ifdef ARM
>       #define JNIEXPORT
> __attribute__((externally_visible,visibility("default")))
>       #define JNIIMPORT
> __attribute__((externally_visible,visibility("default")))
> ================================
> 
> If "osSupport.hpp" was included, XLC++ compiler complained.
> I could not understand, which part was invalid...
> I'm not sure, "osSupport.hpp" is really required on
> NativeImageBuffer.cpp or not...
> 
> I added __xlC__ macro to determine XLC/C++'s version# into jni_md.h. [1]
> 0xD01 means 13.1 by hexadecimal.
> 
> I checked symbol table by "dump -Tv -X64". [2]
> It seemed it was fine, some symbols were hidden.
> 
> Does someone review my code?
> 
> [1]
> https://www.ibm.com/support/knowledgecenter/en/SSGH2K_13.1.3/com.i
> bm.xlc1313.aix.doc/compiler_ref/xlmacros.html
> [2]
> https://www.ibm.com/developerworks/aix/library/au-aix-symbol-
> visibility/index.html
> 
> On 2018-06-01 21:12, Baesken, Matthias wrote:
> > Hi ,  my change  8202322   just  handled  the fact   that  the
> > visibility - flags   are not supported  with  xlc 12.1  ,  so  setting
> > them generated a TON of compile - time  warnings .
> >
> > The introduction of   the  "-qvisibility=hidden"    came with the
> > mapfile removal changes :
> >
> > 8200358: Remove mapfiles for JDK executables
> > http://hg.openjdk.java.net/jdk/jdk/rev/210cf224b690
> >
> > 8200178: Remove mapfiles for JDK native libraries
> > http://hg.openjdk.java.net/jdk/jdk/rev/396ea30afbd5
> >
> > I guess it  might  need further  testing+adjustments  to make  the
> > "visibility hiding" work nicely   with XLC13  ,  but currently  we
> > build only with XLC12 .
> >
> > As a workaround  you might want to  remove  the  "-qvisibility=hidden"
> >  setting for XLC 13 as well  ,  like I did  for XLC12 with  the change
> >   8202322   .
> >
> >
> > Best regards, Matthias
> >
> >
> >
> >
> >> -----Original Message-----
> >> From: Langer, Christoph
> >> Sent: Freitag, 1. Juni 2018 10:57
> >> To: Ichiroh Takiguchi <takiguc at linux.vnet.ibm.com>
> >> Cc: Baesken, Matthias <matthias.baesken at sap.com>; 'build-
> >> dev at openjdk.java.net' <build-dev at openjdk.java.net>; ppc-aix-port-
> >> dev at openjdk.java.net; core-libs-dev at openjdk.java.net; Lindenmaier,
> >> Goetz <goetz.lindenmaier at sap.com>
> >> Subject: RE: RFR : 8202322: AIX: symbol visibility flags not support
> >> on xlc 12.1
> >>
> >> Hi Ichiroh,
> >>
> >> we do not use the XLC 13 compiler on AIX yet here at SAP and I believe
> >> nobody of my colleagues has played with it yet. So you are on a new
> >> playground here ��
> >>
> >> However, I believe the idea in OpenJDK with the abolition of map files
> >> is that
> >> symbols should be invisible externally unless they are declared
> >> exported,
> >> e.g. JNIEXPORT. So I would think "-qvisibility=hidden" should be the
> >> correct
> >> default and whatever JNIEXPORT expands to should contain the right
> >> attributes to get that symbol visible.
> >>
> >> Can you check if either my assumption is completely wrong, JNIEXPORT
> >> does
> >> not expand to the right thing, XLC 13 has a bug or maybe just sume
> >> specific
> >> required symbols are not declared correctly?
> >>
> >> Best regards
> >> Christoph
> >>
> >> > -----Original Message-----
> >> > From: Ichiroh Takiguchi [mailto:takiguc at linux.vnet.ibm.com]
> >> > Sent: Donnerstag, 31. Mai 2018 09:55
> >> > To: Langer, Christoph <christoph.langer at sap.com>
> >> > Cc: Baesken, Matthias <matthias.baesken at sap.com>; 'build-
> >> > dev at openjdk.java.net' <build-dev at openjdk.java.net>; ppc-aix-port-
> >> > dev at openjdk.java.net; core-libs-dev at openjdk.java.net; Lindenmaier,
> >> > Goetz <goetz.lindenmaier at sap.com>
> >> > Subject: RE: RFR : 8202322: AIX: symbol visibility flags not support on xlc
> 12.1
> >> >
> >> > Hello.
> >> > 8202322 was integrated into jdk-11+15.
> >> > I'm using XLC 13.1.3 on AIX 7.1.4.
> >> > Build was failed because of "-qvisibility=hidden" on
> >> > make/lib/LibCommon.gmk.
> >> > According to "XL C/C++ for AIX 13.1.3" documentation [1],
> >> > "-qvisibility=hidden" cannot create shared libraries entry points.
> >> > For example, libverify.so was there, but entry points were not resolved
> >> > by "-lverify" option.
> >> > I think it should be "-qvisibility=default" (I tried, it worked)
> >> > or "-qvisibility=protected" (I had not tried) ?
> >> > I'm not familiar with -qvisibility option, but I'd like to find out
> >> > right way.
> >> >
> >> > [1]
> >> >
> >>
> https://www.ibm.com/support/knowledgecenter/SSGH3R_13.1.3/com.ibm.
> >> > xlcpp1313.aix.doc/compiler_ref/opt_visibility.html
> >> >
> >> > On 2018-05-16 16:08, Langer, Christoph wrote:
> >> > > Hi Matthias,
> >> > >
> >> > > yes, reviewed.
> >> > >
> >> > > Best regards
> >> > > Christoph
> >> > >
> >> > > From: Baesken, Matthias
> >> > > Sent: Mittwoch, 16. Mai 2018 09:06
> >> > > To: Langer, Christoph <christoph.langer at sap.com>;
> >> > > 'build-dev at openjdk.java.net' <build-dev at openjdk.java.net>;
> >> > > ppc-aix-port-dev at openjdk.java.net; core-libs-dev at openjdk.java.net
> >> > > Cc: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>
> >> > > Subject: RE: RFR : 8202322: AIX: symbol visibility flags not support on
> >> > > xlc 12.1
> >> > >
> >> > > Hi  Christoph can I add you as second reviewer  (other reviewer was
> >> > > Erik Joelsson) can push the change ?
> >> > >
> >> > > Best regards, Matthias
> >> > >
> >> > >
> >> > >
> >> > > From: Langer, Christoph
> >> > > Sent: Donnerstag, 26. April 2018 16:38
> >> > > To: Baesken, Matthias
> >> > > <matthias.baesken at sap.com<mailto:matthias.baesken at sap.com>>;
> >> > > 'build-dev at openjdk.java.net'
> >> > > <build-dev at openjdk.java.net<mailto:build-
> dev at openjdk.java.net>>;
> >> > > ppc-aix-port-dev at openjdk.java.net<mailto:ppc-aix-port-
> >> > dev at openjdk.java.net>;
> >> > > core-libs-dev at openjdk.java.net<mailto:core-libs-
> >> dev at openjdk.java.net>
> >> > > Cc: Simonis, Volker
> >> > > <volker.simonis at sap.com<mailto:volker.simonis at sap.com>>
> >> > > Subject: RE: RFR : 8202322: AIX: symbol visibility flags not support on
> >> > > xlc 12.1
> >> > >
> >> > > Hi Matthias,
> >> > >
> >> > > to me the change in principal looks good.
> >> > >
> >> > > I'm wondering if it is possible to do a comparison like xlc < 13 (e.g.
> >> > > extract major number before the first dot, then compare numerically)
> -
> >> > > but maybe it is too complicated and the current single version
> compare
> >> > > suits our needs ?
> >> > >
> >> > > Best regards
> >> > > Christoph
> >> > >
> >> > > From: Baesken, Matthias
> >> > > Sent: Donnerstag, 26. April 2018 16:14
> >> > > To: 'build-dev at openjdk.java.net'
> >> > > <build-dev at openjdk.java.net<mailto:build-
> dev at openjdk.java.net>>;
> >> > > ppc-aix-port-dev at openjdk.java.net<mailto:ppc-aix-port-
> >> > dev at openjdk.java.net>;
> >> > > core-libs-dev at openjdk.java.net<mailto:core-libs-
> >> dev at openjdk.java.net>
> >> > > Cc: Langer, Christoph
> >> > > <christoph.langer at sap.com<mailto:christoph.langer at sap.com>>;
> >> Simonis,
> >> > > Volker <volker.simonis at sap.com<mailto:volker.simonis at sap.com>>
> >> > > Subject: RFR : 8202322: AIX: symbol visibility flags not support on xlc
> >> > > 12.1
> >> > >
> >> > > Hello  ,  could you please review this small adjustment to  the symbol
> >> > > visibility compilation settings on AIX ?
> >> > > Currently  we use  XLC 12.1  to compile  JDK on AIX .
> >> > >
> >> > > However XLC 12.1   does not support  the "-qvisibility=hidden"
> >> > > setting currently set on AIX.
> >> > > It was introduced with  XLC 13.1 . Christoph found some info about it
> >> > > here :
> >> > >
> >> > > https://www.ibm.com/developerworks/aix/library/au-aix-symbol-
> >> > visibility-part2/index.html
> >> > >
> >> > > Setting it  only generates  hundreds  of warnings  in the build log ,
> >> > > warnings look like this :
> >> > > XlC12.1
> >> > >
> >> > > bash-4.4$ xlC -qversion
> >> > > IBM XL C/C++ for AIX, V12.1 (5765-J02, 5725-C72)
> >> > > Version: 12.01.0000.0019
> >> > >
> >> > > bash-4.4$ xlC -qvisibility=hidden sizeof.c -o sizeof_aixxlc
> >> > > 1506-173 (W) Option visibility=hidden is not valid. Enter xlC for list
> >> > > of valid options.
> >> > >
> >> > > Compare to XLC13.1
> >> > >
> >> > > bash-3.00$ xlC -qversion
> >> > > IBM XL C/C++ for AIX, V13.1 (5725-C72, 5765-J07)
> >> > > Version: 13.01.0000.0008
> >> > > bash-3.00$ xlC -qvisibility=default sizeof.c -o sizeof_aixxlc
> >> > > bash-3.00$ xlC -qvisibility=hidden sizeof.c -o sizeof_aixxlc
> >> > >
> >> > >
> >> > > So it is better to avoid  setting these flags when using xlc12.1   .
> >> > > Please review :
> >> > >
> >> > > Bug :
> >> > >
> >> > > https://bugs.openjdk.java.net/browse/JDK-8202322
> >> > >
> >> > > Change :
> >> > >
> >> > > http://cr.openjdk.java.net/~mbaesken/webrevs/8202322/
> >> > >
> >> > >
> >> > > Best regards, Matthias

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