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

[Patrick Zhang]

Ping...

Apply for a sponsor for this simple patch. 

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

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
>