[carussell]

FWIW, the need to bootstrap a cross-compiler from source is not inherent to cross-compilers; it's possible to implement a compiler in such a way that every version of the compiler is automatically a cross-compiler.

I remember a few years back when I was trying to play with MINIX. Tanenbaum got several million EUR and hired some grad students to work on the thing. They promptly replaced much of the system with NetBSD. ("Perhaps too much", you can hear Tanenbaum say in one of his talks.) As a result of this the system compiler ACK was switched out for LLVM/clang. I complained on the mailing list about this because a full system build from source is something that used to be doable in <10 minutes—something Tanenbaum used to boast about—and it was now taking 3 hours if you decided to blow away your source/build directory and do a from-scratch build. The worst part is that the MINIX core, i.e., all the interesting parts, still only accounted for ~10 minutes of that build time, and virtually all the rest was spent compiling and then recompiling LLVM. The response I got from one of the aforementioned grad students was that this is "just how cross-compilers work". No, pal; that's how the compiler that you chose works.

Later, the Go folks fixed their compiler to be a cross-compiler by default. See https://dave.cheney.net/2015/03/03/cross-compilation-just-go...

IMO, it's unforgivable that any given mainstream toolset wouldn't make this a baseline project goal.

[mveety]

The Plan 9 compilers work exactly like this, every compile is a cross-compile. It's extremely convenient because you can do all of your builds on your really fast machine for all of your other machines or if you're using a slow machine. It's one of the reasons I can live happily with a raspberry pi as one of my main workstations. All you need to do to build for a different target is change $objtype.

[exDM69]

Afaik LLVM/Clang doesn't need bootstrapping from source for cross-compiling, but you can choose to include/exclude target support at build time. GCC and binutils can only have one target.

Was the LLVM/Clang build done for building a cross compiler to build Minix or was it to build a compiler that runs on Minix? The latter would be unavoidable, but for the former just having LLVM pre-installed on the build machine should do.

[bogomipz]

>"I remember a few years back when I was trying to play with MINIX. Tanenbaum got several million EUR and hired some grad students to work on the thing."

This piqued my interest, what was this project exactly? Can you elaborate on this anecdote?