roc/examples/shared-quicksort/platform

Rebuilding the host from source

Here are the current steps to rebuild this host. These steps can likely be moved into a build.rs script after turning host.rs into a cargo project, but that hasn't been attempted yet.

Compile the Rust and C sources

Currently this host has both a host.rs and a host.c. This is only because we haven't figured out a way to convince Rust to emit a .o file that doesn't define a main entrypoint, but which is capable of being linked into one later.

As a workaround, we have host.rs expose a function called rust_main instead of main, and all host.c does is provide an actual main which imports and then calls rust_main from the compiled host.rs. It's not the most elegant workaround, but asking on users.rust-lang.org didn't turn up any nicer approaches. Maybe they're out there though!

To make this workaround happen, we need to compile both host.rs and host.c. First, cd into platform/host/src/ and then run:

$ clang -c host.c -o c_host.o
$ rustc host.rs -o rust_host.o

Now we should have c_host.o and rust_host.o in the curent directory.

Link together the .o files

Next, combine c_host.o and rust_host.o into host.o using ld -r like so:

$ ld -r c_host.o rust_host.o -o host.o

Move host.o into the appropriate platform/ subdirectory based on your architecture and operating system. For example, on macOS, you'd move host.o into the platform/host/x86_64-unknown-darwin10/ directory.

All done!

Congratulations! You now have an updated host.

It's now fine to delete c_host.o and rust_host.o, since they were only needed to produce host.o.