OpenJDK fails to build with GCC when the #include<time.h> inside zip.cpp comes from a non-sysroot path

[David Holmes]

Hi Patrick,

On 13/12/2018 1:23 pm, Patrick Zhang wrote:
> Ping...
> 
> Apply for a sponsor for this simple patch.

Seems no one wants to own this one :(

> I doubt if I could have permission to file the issue/bug report anywhere, could anyone kindly give a guidance? Thanks.

I have filed:

https://bugs.openjdk.java.net/browse/JDK-8215976

to cover this and linked to the discussion threads.

The appropriate owners still need to review this, but I'm not sure who 
that may be these days.

Cheers,
David
-----

> 
> Regards
> Patrick
> 
> -----Original Message-----
> From: core-libs-dev <core-libs-dev-bounces at openjdk.java.net> On Behalf Of Patrick Zhang
> Sent: Thursday, December 6, 2018 4:28 PM
> To: core-libs-dev at openjdk.java.net; David Holmes <david.holmes at oracle.com>
> Cc: Florian Weimer <fweimer at redhat.com>
> Subject: RE: OpenJDK fails to build with GCC when the #include<time.h> inside zip.cpp comes from a non-sysroot path
> 
> To All,
> Who could help sponsor this simple patch (may require a wide range of building tests)? Thanks in advance.
> 
> Regards
> Patrick
> 
> -----Original Message-----
> From: David Holmes <david.holmes at oracle.com>
> Sent: Monday, December 3, 2018 8:11 AM
> To: Patrick Zhang <patrick at os.amperecomputing.com>; Florian Weimer <fweimer at redhat.com>
> Cc: core-libs-dev at openjdk.java.net
> Subject: Re: OpenJDK fails to build with GCC when the #include<time.h> inside zip.cpp comes from a non-sysroot path
> 
> Hi Patrick,
> 
> On 30/11/2018 11:41 pm, Patrick Zhang wrote:
>> Thanks Florian, the "-isystem /usr/include" is helpful to my case, I see gcc.gnu.org says that "it gets the same special treatment that is applied to the standard system directories". As such the issue gets hidden (error suppressed).
>>
>> Hi David,
>> Thanks for your suggestion. My intention was to limit the influence range as far as I could since I don't have other systems except CentOS/Fedora to verify (even just smoke test) all paths.
> 
> You'd need some assistance testing a wider range of platforms but that can be arranged.
> 
>> In addition, if we make below update, does it mean the macro " _REENTRANT " can be removed too? This is probably the only place where _REENTRANT gets used AFAIK.
> _REENTRANT is also examined by system headers. It's probably legacy but would require more investigation.
> 
> Cheers,
> David
> 
>> #ifdef _MSC_VER // Windows
>> #define gmtime_r(t, s) gmtime(t)
>> #endif
>>
>> Regards
>> Patrick
>>
>> -----Original Message-----
>> From: Florian Weimer <fweimer at redhat.com>
>> Sent: Thursday, November 29, 2018 8:02 PM
>> To: David Holmes <david.holmes at oracle.com>
>> Cc: Patrick Zhang <patrick at os.amperecomputing.com>;
>> jdk-dev at openjdk.java.net; core-libs-dev at openjdk.java.net
>> Subject: Re: OpenJDK fails to build with GCC when the #include<time.h>
>> inside zip.cpp comes from a non-sysroot path
>>
>> * David Holmes:
>>
>>> This should really be being discussed on core-libs-dev.
>>
>> Okay, moving the conversation.
>>
>>>> diff -r 70a423caee44 src/share/native/com/sun/java/util/jar/pack/zip.cpp
>>>> --- a/src/share/native/com/sun/java/util/jar/pack/zip.cpp	Tue Oct 09 08:33:33 2018 +0100
>>>> +++ b/src/share/native/com/sun/java/util/jar/pack/zip.cpp	Wed Nov 28 22:13:12 2018 -0500
>>>> @@ -415,9 +415,7 @@
>>>>         ((uLong)h << 11) | ((uLong)m << 5) | ((uLong)s >> 1);
>>>>     }
>>>>     -#ifdef _REENTRANT // solaris
>>>> -extern "C" struct tm *gmtime_r(const time_t *, struct tm *); -#else
>>>> +#if !defined(_REENTRANT) // linux
>>>>     #define gmtime_r(t, s) gmtime(t)
>>>>     #endif
>>>>     /*
>>>
>>> Under the theme "two wrongs don't make a right" the use of _REENTRANT
>>> here is totally inappropriate AFAICS. It seems to be a misguided
>>> attempt at determining whether we need the thread-safe gmtime_r or
>>> not
>>> - and the answer to that should always be yes IMHO.
>>>
>>> We define _REENTRANT for:
>>> - linux
>>> - gcc
>>> - xlc
>>>
>>> So the original code will define:
>>>
>>> extern "C" struct tm *gmtime_r(const time_t *, struct tm *);
>>>
>>> for linux (and AIX with xlc?) but not Solaris, OS X or Windows.
>>>
>>> But Solaris has gmtime_r anyway. So the existing code seems a really
>>> convoluted hack. AFAICS we have gmtime_r everywhere but Windows
>>> (where gmtime is already thread-safe). So it seems to me that all we
>>> should need here is:
>>>
>>> -#ifdef _REENTRANT // solaris
>>> -extern "C" struct tm *gmtime_r(const time_t *, struct tm *); -#else
>>> +#ifdef _MSC_VER // Windows
>>>    #define gmtime_r(t, s) gmtime(t)
>>>    #endif
>>
>> That looks much cleaner.
>>
>> Thanks,
>> Florian
>>