RFR: JDK-8152545: Use preprocessor instead of compiling a program to generate native nio constants

[Erik Joelsson]

On 2016-03-24 12:15, Alan Bateman wrote:
>
> On 23/03/2016 16:14, Erik Joelsson wrote:
>> :
>>
>> On 2016-03-23 12:13, Erik Joelsson wrote:
>>> There are however 3 that, at least on Linux, are defined as an enum 
>>> and not constants, which makes them unavailable to the preprocessor. 
>>> These are:
>>>
>>> IPPROTO_TCP = 6
>>> IPPROTO_IP = 0
>>> IPPROTO_PV6 = 41
>>>
>>> I would say that this is fine. They have the same value on all our 
>>> supported platforms and are actually part of the IP spec. I cannot 
>>> imagine a reason for ever defining them differently. So the solution 
>>> is to simply define these as constants in the java source.
>>>
>>> By fixing this, cross compiling new or existing platforms becomes 
>>> much easier.
>>>
>>> I have verified this patch by manually comparing the output and by 
>>> running the jdk_nio tests in JPRT.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8152545
>>> Webrev: http://cr.openjdk.java.net/~erikj/8152545/webrev.jdk.01/
>
> The hard coded values should be okay because they are standard, for 
> example RFC 2292 defines IPPROTO_IPV6 as 41, TCP is protocol number 6.
>
> Is the #undef sun really needed? It otherwise looks good to me. We can 
> fix up the very long lines at some point to get it consistent with the 
> other code in this area.
>
When running this on Solaris without "#undef sun", the package line 
ended up being "package  1 .nio.fs". That's the drawback/scary part of 
using the preprocessor on something that isn't strictly C source, you 
might get unexpected matches.

If you want me to break up lines, I will do it.

/Erik