RFR: 8314949: linux PPC64 Big Endian: Implementation of Foreign Function & Memory API

[Maurizio Cimadamore]

On Thu, 24 Aug 2023 13:56:12 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> I've found a way to solve the remaining FFI problem on linux PPC64 Big Endian. Large structs (>8 Bytes) which are passed in registers or on stack require shifting the Bytes in the last slot if the size is not a multiple of 8. This PR adds the required functionality to the Java code.
> 
> Please review and provide feedback. There may be better ways to implement it. I just found one which works and makes the tests pass:
> 
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR   
>    jtreg:test/jdk/java/foreign                          88    88     0     0   
> 
> 
> Note: This PR should be considered as preparation work for AIX which also uses ABIv1.

src/java.base/share/classes/jdk/internal/foreign/abi/ppc64/ABIv1CallArranger.java line 33:

> 31:  * PPC64 CallArranger specialized for ABI v1.
> 32:  */
> 33: public class ABIv1CallArranger extends CallArranger {

Wouldn't it be more natural for CallArranger to have an abstract method (or even a kind() accessor for the different kinds of ABI supported) and then have these specialized subclasses return the correct kind? It seems to me that setting the `useXYZAbi` flag using an instanceof test is a little dirty.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15417#discussion_r1304966196