3: The Mantle project is mostly orthogonal to OpenCL from what I've heard at APU13. Shaders & Compute Kernels are written in HLSL.
I would be very interested in answers to the other questions myself.
Right now i can not say anything onthis. Please wait for the some time.
Protecting OpenCL code
1) I'm not sure that SPIR (or even CUDA) will protect your source code. You can find some CUDA dissassembler around !
2) If you want to protect your CL code, you have to
a) obfuscate it
b) embed it in your .dll/libs etc...
c) use some code encryption
It just depend of the security level you want to reach... but even a .dll can be dissassembled... nothing is "unhackable" you know ;-)
On my side I think that it is more important to improve the performance of the current OpenCL SDK, and to work more of fixing the issues. (Than always adding new features when the base is not robust !)
Any update on when an OpenCL 2.0 driver will be out? The best I can find is "OpenCL 2.0 will be our primary enablement path with a new driver available later this year" posted 3/3/2014 on http://developer.amd.com/tools-and-sdks/opencl-zone/opencl-tools-sdks/opencl-1-2-beta-driver/.
We’re still on track to release OpenCL 2.0 later this year. However, we are not ready to announce specific availability dates at this time.