| The whole "stage1/2/3" jazz is about our bootstrap process; that is, the way you get a Zig compiler starting from nothing but a C compiler. This is a tricky problem because of the fact that the Zig compiler is written in Zig. The bootstrap is unfortunately quite slow to run, for two main reasons: * We want the final Zig binary it produces to be optimized using LLVM, and LLVM is incredibly slow. * The start of the bootstrap chain involves a kinda-weird step where we translate a WASM binary to a gigantic C file which we then build; this takes a while and makes the first Zig compiler in the process ("stage1"/"zig1") particularly slow. Luckily, you very rarely need to bootstrap! Most of the time, you can simply download a recent Zig binary from ziglang.org. The only reason the bootstrap process exists is essentially so you can make that tarballs yourself (useful if you want to link against system LLVM, or optimize for your native CPU, or you are a distro package maintainer). You don't actually need to do it to develop the compiler; you just need to get a relatively recent build of Zig to use to build the compiler, and it's fine to grab that from ziglang.org (or a mirror). Once you have that, it's as simple as `zig build -Dno-lib` in the Zig repository root. The `-Dno-lib` option just prevents the build script from copying the contents of the `lib/` directory into your installation prefix (zig-out by default); that's desirable to avoid when working on the compiler because it's a lot of files so can take a while to copy. You can also add `-Ddev=x86_64-linux` to build a smaller subset of compiler functionality, speeding up the build more. For the other `-Ddev` options, look at the fields of `Env` in `src/dev.zig`. |