[foreign] RFR 8216484: jextract LayoutUtils has to be modified for Windows

[Jorn Vernee]

I think this sounds good. It's probably a premature optimization to 
cache the Layouts since they are not expensive to create in this case. 
(plus no-cache is much simpler to implement)

updated webrev: 
http://cr.openjdk.java.net/~jvernee/panama/webrevs/windows_jextract/webrev.02/

Jorn

Maurizio Cimadamore schreef op 2019-01-14 15:33:
> Or, remove the cache entirely (we can add it back later if performance
> really becomes a concern)
> 
> Maurizio
> 
> On 14/01/2019 06:31, Sundararajan Athijegannathan wrote:
>> jextract supports ToolProvider interface. It is possible to create 
>> multiple instances of jextract in the same process. LayoutUtils has  a 
>> static cache which is initialized using sizes obtained from clang 
>> library. In theory it is possible that we may get different sizes for 
>> types depending on preprocessor settings, 32/64 bit app etc. I think 
>> it is better if we associate this cache with the current Context 
>> instance.
>> 
>> -Sundar
>> 
>> On 12/01/19, 6:58 PM, Jorn Vernee wrote:
>>> Hi,
>>> 
>>> Continuing from [1, 2]
>>> 
>>> I have polished the previous patch a little.
>>> 
>>> Instead of doing the minimum needed for Windows support I've replaced 
>>> all the LayoutUtils.Types constants, and instead am querying the type 
>>> size from libclang and then caching the result, since libclang seems 
>>> to know the right size to use for the platform.
>>> 
>>> I have been looking at the libclang API and there doesn't seem to be 
>>> a way to specify the target platform. I think it always uses the ABI 
>>> of the platform it was built for.
>>> 
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8216484
>>> Updated Webrev: 
>>> http://cr.openjdk.java.net/~jvernee/panama/webrevs/windows_jextract/webrev.01/
>>> 
>>> Cheers,
>>> Jorn
>>> 
>>> [1] : 
>>> https://mail.openjdk.java.net/pipermail/panama-dev/2019-January/003680.html
>>> [2] : 
>>> https://mail.openjdk.java.net/pipermail/panama-dev/2019-January/003683.html