graal-core cannot use Accessor

[jtulach]

Right now the graal-core uses Truffle class from an implementation package: https://github.com/graalvm/graal-core/blob/6a3900d09cc4aa94196c58a9b136e4d422b6055b/graal/com.oracle.graal.truffle/src/com/oracle/graal/truffle/OptimizedCallTarget.java#L630

Such tight coupling between Truffle and graal-core will force us to release and use Truffle and graal+core in the same time. That is far from ideal. There shall be explicit, more stable API (probably more an SPI) for communication between Truffle and various runtimes.

[chumer]

From my discussion with @jtulach I can derive that the best thing how to tackle this problem would be an SPI using an abstract class (so it can be evolved). This way guest languages could no longer access the runtime implementation directly but with an API. Truffle classes should be able to communicate directly with the runtime SPI so they can establish a private communication channel to implement features like #70 without the use of Accessor.

[jtulach]

Pull request created: https://github.com/graalvm/graal-core/pull/135

[jtulach]

Both graalvm/graal-core#135 and #139 are ready to be integrated. Please review.

[chumer]

The TMVCI API got successfully integrated. Closing.