[foreign] RFR: Windows support

[Sundararajan Athijegannathan]

The 4 bugs (including the preexisting one) are as follows:

1) Library.getDefault() does not work on Windows

https://bugs.openjdk.java.net/browse/JDK-8211060

2) Binder changes are needed to support paname foreign API on Windows

https://bugs.openjdk.java.net/browse/JDK-8216485

3)  jextract LayoutUtils has to be modified for Windows

https://bugs.openjdk.java.net/browse/JDK-8216484

4) jextract tests have to be modified to run on Windows platform

https://bugs.openjdk.java.net/browse/JDK-8216483

PS. I'm running the test patch on Mac and Linux to make sure that the 
testing is fine on other platforms.

Thanks,
-Sundar

On 10/01/19, 6:14 PM, Maurizio Cimadamore wrote:
> Hi Jorn,
> Thanks for the hard work; we are in the process of reviewing the 
> changes. Here's what we'll do:
>
> 1) we will create issues for each of the patches (Sundar is doing that 
> as we speak)
> 2) we will try to get easier changes in sooner rather  than later 
> (that is, patches 1, 3, 4)
> 3) in parallel, I'll be doing an in-depth review of your binder 
> changes and perhaps start a separate thread on that
>
> Thanks
> Maurizio
>
>
> On 09/01/2019 21:17, Jorn Vernee wrote:
>
>> Hi,
>>
>> I have fixed the last few failing tests on Windows so this is an RFR 
>> for adding Windows support to Panama FFI. There's a lot of changes so 
>> I've split it into 4 patches. We should probably focus on one of 
>> these one at a time, but I wanted to include all the changes needed 
>> to pass the tests at least. It's probably best to start with [2], 
>> since that implements the core functionality.
>>
>> Default lib fixes [1] (needed for the default library to work on 
>> Windows)
>> Hotspot, binder tweaks [2] (Changes to the stub generation and shared 
>> binder code. Includes the Windows implementation of SystemABI)
>> jextract tweaks [3] (minor jextract portability changes)
>> test tweaks [4] (changes needed to run, and pass the tests on Windows)
>>
>> There are some tests that are disabled:
>>   - EmptyStructTest; Empty structs are a GCC extension.
>>   - BadBitfieldTest; this is testing for a problem the MSVC ABI 
>> doesn't seem to have.
>>   - StdioTest; relies on standard system header path, which on 
>> Windows is more tricky to find.
>>   - ComplexTest; Windows complex types work very differently in C 
>> source, so the current test doesn't compile.
>>   - LongDoubleTest; long double is only 64 bits on Windows. This 
>> might need a replacement test still, but it should work the same as 
>> `double` on Windows.
>>   - Getpid; No getpid on Windows in the C standard.
>>   - UnixSystem; Windows is not unix.
>>
>> (Some tests specifically for Windows could be added, but I'm leaving 
>> that for a different RFR)
>>
>> Changes for [1]:
>>   - replace default library handle with a findEntryInProcess since 
>> Windows doesn't have an RTLD_DEFAULT equivalent.
>>
>> Changes for [2]:
>>   - changed upcall/downcall stub generation to follow the MS ABI on 
>> windows (using compiler switches)
>>   - added SKIPs to shuffle recipe generation when e.g. the first 
>> float is passed in the second float register (which can be the case 
>> on windows).
>>   - moved boxValue and unboxValue into SystemABI, since they turned 
>> out to be ABI specific, and made tweaks to the windows version for 
>> handeling structs being passed by value.
>>   - moved upcall stub natives into shared ABI package.
>>   - Let each ABI have it's own VarargsInvoker implementation, since 
>> we need to propagate more info about which arguments are variadic on 
>> windows.
>>   - CallingSequence::storageOffset is no longer relying on 
>> Storage::getStorageIndex, since that is not the same as what's 
>> actually needed; being the index of the binding. (the 2 can differ on 
>> windows, but not on sysv).
>>   - Added Windows ABI implementation classes based on the SysV ones.
>>   - Let UniversalUpcallHandler write the in-memory-return pointer to 
>> RAX since that is required on Windows (and I think this change is 
>> portable).
>>
>> Changes for [3]:
>>   - instead of hardcoding the size of `long` `unsigned long` and 
>> `long double`, delegate to libclang to tell us the size, since these 
>> types have different sizes on the 2 ABIs. (This is pretty ad-hoc, so 
>> probably needs to be improved. But, I have little experience with the 
>> jextract code, so I'm open to suggestion of how to better fix this)
>>
>> Changes for [4]:
>>   - added dll exports for native symbols using compiler switches.
>>   - added test for small (fits-in-register) struct by-value passing, 
>> since windows has special handling for those.
>>   - removed depencies on POSIX functions from some tests where it 
>> wasn't really needed, so they could run on windows.
>>   - propagate clang library name to TestJextractFFI, since on Windows 
>> we need to load "libclang".
>>   - let Runner test use windows specific files to compare with for 
>> bitfields.h and simple.h
>>   - use `long long` instead of `long` in some cases since `long long` 
>> is 64 bits on SysV and MSx64
>>
>> Thanks,
>> Jorn
>>
>> [1] : 
>> http://cr.openjdk.java.net/~jvernee/panama/webrevs/8211060/webrev.01/
>> [2] : 
>> http://cr.openjdk.java.net/~jvernee/panama/webrevs/windows/webrev.03/
>> [3] : 
>> http://cr.openjdk.java.net/~jvernee/panama/webrevs/windows_jextract/webrev.00/
>> [4] : 
>> http://cr.openjdk.java.net/~jvernee/panama/webrevs/windows_tests/webrev.02/