Now that mozilla/sccache#43 is fixed the caching works for MinGW on Windows. We
still can't use it for MSVC just yet, but I'll try to revive that branch at some
point.
Currently CI builds can fail spuriously during the LLVM build (#39003). I
believe this is due to sccache, and I believe that in turn was due to the fact
that the sccache server used to just be a raw mio server. Historically raw mio
servers are quite complicated to get right, but this is why we built Tokio! The
sccache server has been migrated to Tokio which I suspect would fix any latent
issues.
I have no confirmation of this (never been able to reproduce the deadlock
locally), but my hunch is that updating sccache to the master branch will fix
the timeouts during the LLVM build.
The binaries previously came from Gecko's infrastructure, but I've built new
ones by hand for Win/Mac/Linux and uploaded them to our CI bucket.
This commit adds support to the build system to execute test suites that cannot
run natively but can instead run inside of a QEMU emulator. A proof-of-concept
builder was added for the `arm-unknown-linux-gnueabihf` target to show off how
this might work.
In general the architecture is to have a server running inside of the emulator
which a local client connects to. The protocol between the server/client
supports compiling tests on the host and running them on the target inside the
emulator.
Closes#33114
