RFR: 8224087: Compile C code for at least C99 Standard compliance

[dean.long at oracle.com]

Isn't that going to break inline asm?

dl

On 5/20/19 3:40 PM, Erik Joelsson wrote:
> That sounds good to me. I missed that distinction before, but pure c99 
> does sound better.
>
> /Erik
>
> On 2019-05-20 15:31, David Holmes wrote:
>> Hi Volker,
>>
>> Thanks for the xlc update - I will incorporate that.
>>
>> It has been suggested that we actually set c99 rather than gnu99 to 
>> avoid any GNU extensions creeping in. Does anyone have any concerns 
>> with doing that?
>>
>> Thanks,
>> David
>>
>> On 21/05/2019 12:05 am, Volker Simonis wrote:
>>> Hi David,
>>>
>>> thanks for considering AIX in your change.
>>>
>>> With OpenJDK 13 we've moved to XLC 16 which has a new Clang based
>>> frontend. The "ucs" feature-suboption [1] you're using in your change
>>> is only supported in the old, xlc compiler but not in the new xlclang
>>> any more [2]. However, the good news is that the new xlclang now
>>> supports the same "-std=gn99" option like gcc and clang, so you could
>>> easily handle the xlc case now together with gcc and clang as shown in
>>> this webrev:
>>>
>>> http://cr.openjdk.java.net/~simonis/webrevs/2019/8224087/
>>>
>>> Otherwise, your change looks good!
>>>
>>> Please let me know once you've pushed it. I opened "8224214: [AIX]
>>> Remove support for legacy xlc compiler" [3] for further cleannups
>>> because we still set some "-qlanglvl" options for C++ which aren't
>>> supported by the new compiler either.
>>>
>>> Best regards,
>>> Volker
>>>
>>> [1] 
>>> https://www.ibm.com/support/knowledgecenter/SSGH3R_12.1.0/com.ibm.xlcpp121.aix.doc/compiler_ref/opt_langlvl.html
>>> [2] 
>>> https://www.ibm.com/support/knowledgecenter/SSGH3R_16.1.0/com.ibm.xlcpp161.aix.doc/compiler_ref/opt_langlvl_aix.html
>>>
>>>
>>> On Mon, May 20, 2019 at 9:40 AM David Holmes 
>>> <david.holmes at oracle.com> wrote:
>>>>
>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8224087
>>>> webrev: http://cr.openjdk.java.net/~dholmes/8224087/webrev/
>>>>
>>>> The need to remove a for-loop declaration expression to appease gcc 
>>>> 4.8
>>>> annoyed me enough to investigate setting C99 as our minimum allow
>>>> C-language level when compiling. It turned out to be a lot more 
>>>> complex
>>>> a situation than I thought due to toolchain quirks. See lots of 
>>>> details
>>>> in the bug report.
>>>>
>>>> To summarise the changes:
>>>> - gcc: force to -std=gnu99
>>>> - clang force to -std=gnu99
>>>> - Solaris studio - no effective change
>>>> - Visual Studio - no change
>>>> - xlc - no effective change (but we use the explicit flag rather than
>>>> accepting it as default)
>>>>
>>>> I've checked how this works with all the toolchains except xlc as I 
>>>> have
>>>> no access to that. Some assistance from someone who can verify the
>>>> correctness on xlc would be appreciated.
>>>>
>>>> Thanks,
>>>> David