RFR : 8204541 Correctly support AIX xlC 13.1 symbol visibility flags

7 Jun 2018

Hello.

Could you review it ?
Bug:    https://bugs.openjdk.java.net/browse/JDK-8204541
Change: http://cr.openjdk.java.net/~clanger/webrevs/8204541.0/

Thanks,
Ichiroh Takiguchi
IBM Japan, Ltd.

-------- Original Message --------
Subject: RE: RFR : 8202322: AIX: symbol visibility flags not support on 
xlc 12.1
Date: 2018-06-07 20:43
 From: "Langer, Christoph" <christoph.langer@sap.com>
To: Ichiroh Takiguchi <takiguc@linux.vnet.ibm.com>
Cc: "'build-dev@openjdk.java.net'" <build-dev@openjdk.java.net>, 
"ppc-aix-port-dev@openjdk.java.net" <ppc-aix-port-dev@openjdk.java.net>, 
"core-libs-dev@openjdk.java.net" <core-libs-dev@openjdk.java.net>, 
"Lindenmaier, Goetz" <goetz.lindenmaier@sap.com>, "Baesken, Matthias" 
<matthias.baesken@sap.com>

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@linux.vnet.ibm.com]
Sent: Dienstag, 5. Juni 2018 08:59
To: Baesken, Matthias <matthias.baesken@sap.com>
Cc: Langer, Christoph <christoph.langer@sap.com>; 'build-
dev@openjdk.java.net' <build-dev@openjdk.java.net>; ppc-aix-port-
dev@openjdk.java.net; core-libs-dev@openjdk.java.net; Lindenmaier,
Goetz <goetz.lindenmaier@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
...
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@linux.vnet.ibm.com>
Cc: Baesken, Matthias <matthias.baesken@sap.com>; 'build-
dev@openjdk.java.net' <build-dev@openjdk.java.net>; ppc-aix-port-
dev@openjdk.java.net; core-libs-dev@openjdk.java.net; Lindenmaier,
Goetz <goetz.lindenmaier@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@linux.vnet.ibm.com]
Sent: Donnerstag, 31. Mai 2018 09:55
To: Langer, Christoph <christoph.langer@sap.com>
Cc: Baesken, Matthias <matthias.baesken@sap.com>; 'build-
dev@openjdk.java.net' <build-dev@openjdk.java.net>; ppc-aix-port-
dev@openjdk.java.net; core-libs-dev@openjdk.java.net; Lindenmaier,
Goetz <goetz.lindenmaier@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@sap.com>;
'build-dev@openjdk.java.net' <build-dev@openjdk.java.net>;
ppc-aix-port-dev@openjdk.java.net; core-libs-dev@openjdk.java.net
Cc: Lindenmaier, Goetz <goetz.lindenmaier@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@sap.com<mailto:matthias.baesken@sap.com>>;
'build-dev@openjdk.java.net'
<build-dev@openjdk.java.net<mailto:build-
dev@openjdk.java.net>>;
ppc-aix-port-dev@openjdk.java.net<mailto:ppc-aix-port-
dev@openjdk.java.net>;
core-libs-dev@openjdk.java.net<mailto:core-libs-
dev@openjdk.java.net>
Cc: Simonis, Volker
<volker.simonis@sap.com<mailto:volker.simonis@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)
On 2018-06-01 21:12, Baesken, Matthias wrote:
-
...
...
...
...
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@openjdk.java.net'
<build-dev@openjdk.java.net<mailto:build-
dev@openjdk.java.net>>;
ppc-aix-port-dev@openjdk.java.net<mailto:ppc-aix-port-
dev@openjdk.java.net>;
core-libs-dev@openjdk.java.net<mailto:core-libs-
dev@openjdk.java.net>
Cc: Langer, Christoph
<christoph.langer@sap.com<mailto:christoph.langer@sap.com>>;
Simonis,
Volker <volker.simonis@sap.com<mailto:volker.simonis@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

    

Ichiroh Takiguchi

Langer, Christoph

Ichiroh Takiguchi

Langer, Christoph

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