RFR: [OpenJDK 2D-Dev] JDK-8215296 do not disable c99 on Solaris

Magnus Ihse Bursie magnus.ihse.bursie at oracle.com
Mon Dec 17 15:10:40 UTC 2018 

Sounds like a simpler change, at least for now. Does it pass jdk-submit? Do you intend to push to 12 or 13?

Looks good to me, as long as it doesn't break anything. 

/Magnus

> 17 dec. 2018 kl. 14:12 skrev Baesken, Matthias <matthias.baesken at sap.com>:
> 
> 
> Hello,  please review 
> 
> http://cr.openjdk.java.net/~mbaesken/webrevs/8215296.0/
> 
> in my change just -xc99=%none  is removed, so we do not forbid c99 coding.
> 
> The -Xa compile flag is kept,  no special additional settings are needed to compile png/awt .
> 
> 
> Thanks, Matthias
> 
> 
>> ----------------------------------------------------------------------
>> 
>> Message: 1
>> Date: Fri, 14 Dec 2018 15:39:26 +0100
>> From: Magnus Ihse Bursie <magnus.ihse.bursie at oracle.com>
>> To: Erik Joelsson <erik.joelsson at oracle.com>, build-dev
>>    <build-dev at openjdk.java.net>, "awt-dev at openjdk.java.net"
>>    <awt-dev at openjdk.java.net>, 2d-dev <2d-dev at openjdk.java.net>
>> Subject: Re: [OpenJDK 2D-Dev] RFR: JDK-8215296 do not disable c99 on
>>    Solaris
>> Message-ID: <5874d10e-db2d-8681-a54b-a1eeb6e45994 at oracle.com>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>> 
>> 
>> 
>>> On 2018-12-14 12:49, Magnus Ihse Bursie wrote:
>>> 
>>> 13 dec. 2018 kl. 19:07 skrev Erik Joelsson <erik.joelsson at oracle.com
>>> <mailto:erik.joelsson at oracle.com>>:
>>> 
>>>> 
>>>>> On 2018-12-13 02:11, Magnus Ihse Bursie wrote:
>>>>> 
>>>>>> -D_XPG6
>>>>>> 
>>>>>> ??
>>>>> To be honest, I'm not completely sure about this. Without this
>>>>> define, the build failed with the following error message:
>>>>> Compiler or options invalid for pre-UNIX 03 X/Open applications and
>>>>> pre-2001 POSIX applications
>>>>> 
>>>>> This was triggered by the following section in
>>>>> /usr/include/sys/feature_tests.h:
>>>>> /*
>>>>> * It is invalid to compile an XPG3, XPG4, XPG4v2, or XPG5 application
>>>>> * using c99.  The same is true for POSIX.1-1990, POSIX.2-1992,
>>>>> POSIX.1b,
>>>>> * and POSIX.1c applications. Likewise, it is invalid to compile an
>>>>> XPG6
>>>>> * or a POSIX.1-2001 application with anything other than a c99 or
>>>>> later
>>>>> * compiler.  Therefore, we force an error in both cases.
>>>>> */
>>>>> #if defined(_STDC_C99) && (defined(__XOPEN_OR_POSIX) &&
>>>>> !defined(_XPG6))
>>>>> #error "Compiler or options invalid for pre-UNIX 03 X/Open
>>>>> applications \
>>>>>        and pre-2001 POSIX applications"
>>>>> #elif !defined(_STDC_C99) && \
>>>>>        (defined(__XOPEN_OR_POSIX) && defined(_XPG6))
>>>>> #error "Compiler or options invalid; UNIX 03 and POSIX.1-2001
>>>>> applications \
>>>>>        require the use of c99"
>>>>> #endif
>>>>> 
>>>>> The solution, as also hinted to by searching for other resolutions
>>>>> to this error online, was to provide the _XPG6 system define. But
>>>>> exactly how we end up in feature_tests.h with __XOPEN_OR_POSIX set,
>>>>> without _XPG6 set, and only when compiling this library and not
>>>>> others, I don't know. I also don't understand what the XPG standard
>>>>> refers to, nor what versions 2-5 means or what version 6 has that
>>>>> differs from them.
>>>>> 
>>>>> By setting this flag, I am telling solaris include headers that we
>>>>> want to compile using the XPG standard version 6, instead of an
>>>>> older one. It solves the problem. I am happy enough with this. Are you?
>>>> It looks like this comes from libpng. It has this in
>>>> src/java.desktop//share/native/libsplashscreen/libpng/pngpriv.h:
>>>> 
>>>> /* Feature Test Macros.  The following are defined here to ensure
>>>> that correctly
>>>> * implemented libraries reveal the APIs libpng needs to build and
>>>> hide those
>>>> * that are not needed and potentially damaging to the compilation.
>>>> *
>>>> * Feature Test Macros must be defined before any system header is
>>>> included (see
>>>> * POSIX 1003.1 2.8.2 "POSIX Symbols."
>>>> *
>>>> * These macros only have an effect if the operating system supports
>>>> either
>>>> * POSIX 1003.1 or C99, or both.  On other operating systems
>>>> (particularly
>>>> * Windows/Visual Studio) there is no effect; the OS specific tests
>>>> below are
>>>> * still required (as of 2011-05-02.)
>>>> */
>>>> #ifndef _POSIX_SOURCE
>>>> # define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
>>>> #endif
>>>> 
>>>> This in turn triggers _XOPEN_OR_POSIX to be defined in
>>>> /usr/include/sys/feature_tests.h and so triggers the error.
>>>> 
>>>> What I'm not clear about is if libpng is trying to declare that it
>>>> should not be compiled with any newer standards, and so by doing
>>>> that, we risk introducing problems. Reading in the system header, it
>>>> seems the _XPG6 macro is internal and should not be used by the
>>>> application. It's derived from _XOPEN_SOURCE=600 or
>>>> _POSIX_C_SOURCE=200112L which is what applications should use.
>>> 
>>> Interesting. We should probably define one, or both of these. Perhaps
>>> globally for all native files and compilers. It might have been the
>>> case that the solstudio compiler set _POSIX_C_SOURCE for us before,
>>> prior to setting -std=c99. The following stack overflow article claims
>>> that this is at least the behavior of gcc/clang:
>>> 
>>> https://stackoverflow.com/questions/21867897/c89-and-posix-at-the-
>> same-time
>>> 
>>> 
>>> So we might have had an implicit _POSIX_C_SOURCE that we now miss.
>>> That would explain why this starts to fail. I'll see if I can confirm
>>> this the next time I log into a Solaris computer.
>> Of course it was not as simple. Setting:
>>   ifeq ($(OPENJDK_TARGET_OS), solaris)
>>     LIBSPLASHSCREEN_CFLAGS += -D_POSIX_C_SOURCE=200112L -
>> D_XOPEN_SOURCE=600
>>   endif
>> 
>> instead made us fail with:
>> open/src/java.desktop/unix/native/libsplashscreen/splashscreen_sys.c",
>> line 143: error: incomplete struct/union/enum timezone: tz
>> 
>> I don't have more time to dig into this now. Overall, changes such as
>> these make it all feel a bit scary; I recommend that any change to this
>> be made in JDK 13 and not 12.
>> 
>> /Magnus
>>> 
>>> Otoh, the same article claims, and it sounds reasonable, that we
>>> should set these variables ourself, to be well behaved and to minimize
>>> surprises. And I think this applies to all unix platforms, regardless
>>> of compiler being used. I'll see if I can kick off a test job with
>>> this to see how/if it influences other platforms. But it sounds like
>>> something we should do; the level of posix conformance should be
>>> controlled by us, not left to chance. We also need to verify, of
>>> course, that all platforms we want to support is capable of
>>> supporting  _POSIX_C_SOURCE=200112L. I doubt there's a problem
>> though.
>>> Possibly on AIX...
>>> 
>>> /Magnus
>>> 
>>>> 
>>>> So the the question is, is it ok to override the requirements of
>>>> libpng or should it receive special treatment? If we are fine with
>>>> overriding, then we should use one of the public APIs instead.
>>>> 
>>>> /Erik
>>>> 
>>>>> /Magnus
>>>>> 
>>>>>> 
>>>>>> Thanks,
>>>>>> David
>>>>>> 
>>>>>>> On 13/12/2018 7:02 am, Magnus Ihse Bursie wrote:
>>>>>>> 
>>>>>>> 
>>>>>>>> On 2018-12-12 20:08, Magnus Ihse Bursie wrote:
>>>>>>>> 
>>>>>>>> 
>>>>>>>>> On 2018-12-12 19:12, Magnus Ihse Bursie wrote:
>>>>>>>>> From the bug report:
>>>>>>>>> "Currently  we disable C99 in the Solaris build by setting
>>>>>>>>> -xc99=%none%.
>>>>>>>>> This differs from a lot of other build environments like
>>>>>>>>> gcc/Linux or VS2013/2017 on Windows where C99 features work.
>>>>>>>>> We should remove this difference on Solaris and remove or
>>>>>>>>> replace the setting.
>>>>>>>>> 
>>>>>>>>> Kim Barrett mentioned :
>>>>>>>>> "I merely mentioned the C++14 work as evidence that removing
>>>>>>>>> -xc99=%none% didn?t appear harmful."
>>>>>>>>> However it will take more time until  the C++14 change is in."
>>>>>>>>> 
>>>>>>>>> I am currently running a test build on our CI build system to
>>>>>>>>> confirm that this does not break the Solaris build (but I'd be
>>>>>>>>> highly surprised if it did). I will not push this until the
>>>>>>>>> builds are cleared.
>>>>>>>> Of course it was not that simple... :-( Two AWT libraries (at
>>>>>>>> least) failed to build. I'm currently investigating if there's a
>>>>>>>> simple fix to that.
>>>>>>> New attempt, that fixes the two AWT libraries:
>>>>>>> WebRev:
>>>>>>> http://cr.openjdk.java.net/~ihse/JDK-8215296-build-solstudio-with-
>> c99/webrev.01
>>>>>>> <http://cr.openjdk.java.net/%7Eihse/JDK-8215296-build-solstudio-
>> with-c99/webrev.01>
>>>>>>> 
>>>>>>> 
>>>>>>> Now this passes the CI build test.
>>>>>>> 
>>>>>>> /Magnus
>>>>>>>> 
>>>>>>>> /Magnus
>>>>>>>>> 
>>>>>>>>> /Magnus
>>>>>>>>> 
>>>>>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8215296
>>>>>>>>> Patch inline:
>>>>>>>>> diff --git a/make/autoconf/flags-cflags.m4
>>>>>>>>> b/make/autoconf/flags-cflags.m4
>>>>>>>>> --- a/make/autoconf/flags-cflags.m4
>>>>>>>>> +++ b/make/autoconf/flags-cflags.m4
>>>>>>>>> @@ -559,7 +559,7 @@
>>>>>>>>> TOOLCHAIN_CFLAGS="-errshort=tags"
>>>>>>>>> 
>>>>>>>>> TOOLCHAIN_CFLAGS_JDK="-mt $TOOLCHAIN_FLAGS"
>>>>>>>>> - TOOLCHAIN_CFLAGS_JDK_CONLY="-xc99=%none -xCC -Xa -W0,-
>> noglobal
>>>>>>>>> $TOOLCHAIN_CFLAGS" # C only
>>>>>>>>> + TOOLCHAIN_CFLAGS_JDK_CONLY="-std=c99 -xCC -W0,-noglobal
>>>>>>>>> $TOOLCHAIN_CFLAGS" # C only
>>>>>>>>> TOOLCHAIN_CFLAGS_JDK_CXXONLY="-features=no%except -
>> norunpath
>>>>>>>>> -xnolib" # CXX only
>>>>>>>>> TOOLCHAIN_CFLAGS_JVM="-template=no%extdef -
>> features=no%split_init \
>>>>>>>>>         -library=stlport4 -mt -features=no%except
>>>>>>>>> $TOOLCHAIN_FLAGS"
>

More information about the build-dev mailing list