Is it legal to pass a struct containing a global pointer into a kernel?

OpenCL
1

The following code uses a struct, passed into the kernel, containing a global pointer. The pointer however is not used inside the kernel until initialized to point to the floats0 global float * array. Is there anything in the OpenCL 1.2 spec that says this is/isnt legal?


struct Eigen__TensorEvaluator {
    global float* f0;
    float f1;
};

kernel void foo(global struct Eigen__TensorEvaluator* pstruct, global float* floats0) {
    pstruct[0].f0 = floats0;
    pstruct[0].f0[0] = pstruct[0].f1;
}
2

Pretty sure it is illegal. If you can’t use SVM from 2.0, simply store your element’s position as an int.

3

Seems legal to me as long as you’re not trying to pass a host pointer in there. If you initialize the value and use the value only on the device side, seems completely legit.

4

The thing is, pointers are not guaranteed to remain consistent on a GPU between kernel runs. It can be valid for some particular architecture, but using an undefined behavior is always iffy.