ocl-core doesn't compile on ARM platforms

[skanur]

This is more of a feature request than a bug report.

Compiling an arbitrary OpenCL program that uses ocl crate gives the following error while compiling ocl-core on an ARM device (odroid-XU4)

Compiling ocl-core v0.3.0 (file:///home/odroid/workspace/ubench_rust/ocl/ocl-core)
ocl/ocl-core/src/functions.rs:1202:85: 1202:92 error: the trait bound `std::vec::Vec<*const i8>: std::iter::FromIterator<*const u8>` is not satisfied [E0277]
ocl/ocl-core/src/functions.rs:1202     let kern_string_ptrs: Vec<*const i8> = src_strings.iter().map(|cs| cs.as_ptr()).collect();
                                                                                                                       ^~~~~~~
ocl/ocl-core/src/functions.rs:1202:85: 1202:92 help: run `rustc --explain E0277` to see a detailed explanation
ocl/ocl-core/src/functions.rs:1202:85: 1202:92 note: a collection of type `std::vec::Vec<*const i8>` cannot be built from an iterator over elements of type `*const u8`
ocl/ocl-core/src/functions.rs:1209:9: 1209:54 error: mismatched types [E0308]
ocl/ocl-core/src/functions.rs:1209         kern_string_ptrs.as_ptr() as *const *const i8,
                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ocl/ocl-core/src/functions.rs:1209:9: 1209:54 help: run `rustc --explain E0308` to see a detailed explanation
ocl/ocl-core/src/functions.rs:1209:9: 1209:54 note: expected type `*const *const u8`
ocl/ocl-core/src/functions.rs:1209:9: 1209:54 note:    found type `*const *const i8`
ocl/ocl-core/src/functions.rs:1317:9: 1317:38 error: mismatched types [E0308]
ocl/ocl-core/src/functions.rs:1317         options.as_ptr() as *const i8,
                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ocl/ocl-core/src/functions.rs:1317:9: 1317:38 help: run `rustc --explain E0308` to see a detailed explanation
ocl/ocl-core/src/functions.rs:1317:9: 1317:38 note: expected type `*const u8`
ocl/ocl-core/src/functions.rs:1317:9: 1317:38 note:    found type `*const i8`
error: aborting due to 3 previous errors
error: Could not compile `ocl-core`.

This is not due to bug in your code, but because the rust nightly is not entirely supported for arm. Check this issue here.

The fix I found with some google-fu is to use *const _ instead of *const i8 at these locations. I can confirm this solution compiles fine on ARM and on my laptop (x86_64).

I'll anyway send you a PR soon that fixes this issue. Could you wrap it in a feature and push it upstream?

[c0gent]

Sure, sounds good.

[c0gent]

Let me know how this compiles on your device.

I consider small machines like your 'odroid' to be extremely important to the future of parallel computing. I want to make sure that this library not only supports them, but makes it as easy as possible to develop on them.

[skanur]

Thank you for the merge. I will compile and let you know. Also, I agree on the importance of mobile devices for parallel programming :)