make of llvm freezes on executable llvm-lto (Linux)

I’m on Ubuntu Linux 64-bit, with 4 GB of RAM allocated to it, and I’ve been trying to make llvm with all the bells and whistles, not just clang, but extra, compiler-rt, libcxx, and libcxxabi. Make has made it all the way to llvm-lto, and it seems to get stuck. There is no output, however.

What can I do?

Thanks,
Erika

+llvm-dev -cfe-dev

Is the linker process consuming CPU? Can you run the linker command outside of the build system? Do you have enough disk space? Can you attach a debugger to it and sample the stack trace? (or if you have a profiler profile it).