RFR: 8264774: Implementation of Foreign Function and Memory API (Incubator) [v3]

[Maurizio Cimadamore]

On Wed, 28 Apr 2021 20:40:49 GMT, Mandy Chung <mchung at openjdk.org> wrote:

> > To be clear - by aliasing you mean when the @CallerSensitive implementation is called with invokeinterface - so, e.g. doing `MethodHandles.lookup().findVirtual(CLinker.class, ...)` right?
> 
> Yes. The caller would be java.base if it's invoked via method handle.

I just did a test:


public class TestLookup {
    public static void main(String[] args) throws Throwable {
        MethodHandle handle = MethodHandles.lookup().findVirtual(CLinker.class, "downcallHandle", MethodType.methodType(MethodHandle.class, Addressable.class, MethodType.class, FunctionDescriptor.class));
        CLinker linker = CLinker.getInstance();
        handle.invoke(linker, MemoryAddress.NULL, MethodType.methodType(void.class), FunctionDescriptor.ofVoid());
    }
}


this fails as expected when the handle is invoked. To test I had to disable the check on CLinker.getInstance - otherwise that would have always throw anyway.

Also, on IllegalCaller vs. IllegalAccess - looking more, I think our impl throws IllegalCaller - now that was done because IllegalAccess is a checked exception and we don't want a checked exception here - but the option is called "enableNativeAccess" - is that still ok?

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PR: https://git.openjdk.java.net/jdk/pull/3699