[foreign-memaccess+abi] RFR: 8307461: Linker::nativeLinker should not be restricted

[Jorn Vernee]

On Thu, 4 May 2023 14:36:11 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

> Since `Linker` is a sealed interface, we can now move restricted-ness from the static linker factory, down to the methods which are really problematic, namely `Linker::downcallHandle` and `Linker::upcallStub`.
> 
> With this change, the list of restricted method looks as follows:
> 
> * Linker::downcallHandle
> * Linker::upcallStub
> * MemorySegment::reinterpret
> * SymbolLookup::libraryLookup
> 
> That is, crucially, restricted methods are methods that have a true risk of compromising the integrity of the Java platform. Making Linker::nativeLinker restricted casts too broad of a net, as obtaining the linker is not, per se, a dangerous or unsafe operation.

Might be nice to add testing for `upcallStub` as well to the panama_module tests

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Marked as reviewed by jvernee (Committer).

PR Review: https://git.openjdk.org/panama-foreign/pull/831#pullrequestreview-1413748226