Code changes required after JDK-8291473

[Maurizio Cimadamore]

Hi Filip,
coming back to your original questions:

> I am unsure about changing the C_POINTER layout to be unbounded. 
I think this is how we intended the API to be used. Currently, with JDK 
19 jextract, you get back a MemoryAddress and you can dereference that. 
So it seems logical to preserve same behavior (using the unbounded 
address layout).


>
> I will have to find where jextract decides whether to add a 
> SegmentAllocator to the signature or not, as in case of pointers as 
> the return type, it should not be there.

Yes, I recall having to fight with same issue - in a much of places we 
do some "instanceof MemorySegment" and then assume that, if true, we 
need an allocator. All those places need to be updated to test on the 
return _layout_. Example:

https://github.com/openjdk/jextract/blob/master/src/main/java/org/openjdk/jextract/impl/HeaderFileBuilder.java#L122

Cheers
Maurizio


>
> Best regards,
> Filip
>
> [1] - https://github.com/krakowski/jextract/tree/jdk20
>
> On 04.08.22 15:47, Filip Krakowski wrote:
>> Hi,
>>
>> since jextract does not work with the latest changes introduced in 
>> https://git.openjdk.org/panama-foreign/pull/694, I started to work on 
>> adjusting the sources in [1]. I took the following steps so far:
>>
>>   1. Find & replace all occurrences and imports of "Addressable" and 
>> "MemoryAddress" and replace it with "MemorySegment"
>>   2. Change all occurences of "Linker.downcallType" and 
>> "Linker.upcallType" with "Linker.methodType"
>>   3. Remove duplicate if-statements resulting from Step 1
>>   4. Make C_POINTER$LAYOUT unbounded (in 
>> org.openjdk.jextract.impl.ToplevelBuilder#primitiveLayoutString)
>>   5. Use MemorySegment#equals instead of reference comparison inside 
>> org.openjdk.jextract.clang.org.openjdk.jextract.clang#getLocation
>>   6. Tweak build.gradle so that the user does not have to specify the 
>> jdk home directory. Gradle will automatically search for the 
>> specified JDK version. It can also be instructed to search inside 
>> custom locations using the org.gradle.java.installations.paths 
>> property, which can be set inside ${HOME}/.gradle/gradle.properties.
>>
>> Since my approach is relatively naive ("find & replace" + fixing 
>> compiler and runtime errors), important parts of the code may be 
>> incorrect at the moment. I tested it with my Gradle plugin's demo 
>> project [2], which works. But again, this is only a simple program 
>> just calling printf and doing nothing fancy. In the next step I will 
>> try to rewrite some jtreg tests and see if they pass. Hopefully, this 
>> should point out all incorrect parts.
>>
>> If you want to try it out, you need to compile [1] and add the 
>> resulting "bin"-Folder ("$PROJECT_DIR/build/jextract/bin") to your 
>> PATH. Afterwards [2] should just work by executing "./gradlew run". 
>> If successful, the program should print "Hello World" (using the 
>> native printf function).
>>
>> I would greatly appreciate feedback regarding my general approach to 
>> code changes. In particular, I am unsure about changing the C_POINTER 
>> layout to be unbounded.
>>
>> Best regards,
>> Filip
>>
>> [1] - https://github.com/krakowski/jextract/tree/jdk20
>> [2] - https://github.com/krakowski/jextract-demo
>