Sam Estep (Aug 19 2024 at 18:17): Sam Estep (Aug 19 2024 at 18:17):Hello! :wave: I was able to successfully follow the Cranelift JIT demo to get a working Cranelift JIT hello world example, but I'm having trouble finding a place to look to make a similar "hello world" example for ahead-of-time compilation. I tried using someone's example Brainfuck compiler, but I got linking errors on all my machines (x86 WSL2, ARM64 macOS, and i386 Linux) so I'm not exactly sure how to adapt it so it'll work. I assume there already exists some simple example for producing a static binary using Cranelift; where can I find it?
bjorn3 (Aug 19 2024 at 19:40):Are you passing -lc when linking? And are you defining a main function which you mark as Linkage::Export?
Sam Estep (Sep 04 2024 at 14:56):@bjorn3 sorry for being slow to respond; thankfully the cranefuck author helped me figure out how to get linking working though!
bjorn3 (Sep 04 2024 at 14:58):Wait, why are you directly using ld instead of using gcc or clang? Gcc and clang pass a bunch of flags to the linker to tell it where to find system libraries, which libraries are unconditionally required and so on.
bjorn3 (Sep 04 2024 at 14:59):Pretty much everyone on Unix systems uses gcc, clang or whatever C compiler is the default for the platform instead of directly running the linker.
bjorn3 (Sep 04 2024 at 15:00):This is both a lot more portable and much simpler than reproducing all this logic for every OS you want to target.
bjorn3 (Sep 04 2024 at 15:00):@Sam Estep
Sam Estep (Sep 04 2024 at 15:06):@bjorn3 that makes a lot of sense, sounds like I should be using gcc or clang instead! More generally, I'd like to distribute my compiler as a standalone binary (via musl etc) which itself can produce standalone binaries, so I don't really want to just assume that the user already has gcc or clang installed on their system. What should I do in this case? For instance, it seems like the Rust compiler itself comes with a linker, but I assume that's because Rust bundles LLVM. Is there a way I can achieve this same UX but with Cranelift?
bjorn3 (Sep 04 2024 at 15:10):Do you mean rust-lld? On all Unix systems we (rustc) actually tell gcc/clang to use rust-lld as linker rather than directly invoking rust-lld.
Sam Estep (Sep 04 2024 at 15:11):OK gotcha; so, what happens when someone installs Rust but doesn't already have gcc or clang installed?
bjorn3 (Sep 04 2024 at 15:11):You get an error that gcc or clang was not found.
Sam Estep (Sep 04 2024 at 15:12):What about on Windows?
Sam Estep (Sep 04 2024 at 15:14):Sounds like you're saying I essentially can't just distribute one standalone binary for my compiler and also produce standalone binaries from user programs, is that accurate?
bjorn3 (Sep 04 2024 at 15:14):For wasm and embedded systems without OS rustc does directly invoke rust-lld as for those there is no libc and such.
For MSVC Windows by default we expect link.exe in the PATH, but can run rust-lld in link.exe mode. Even so you need the Windows SDK installed (which we legally can't redistribute) for import libraries and a couple of things that get statically linked into the executable. For MinGW Windows we ship a copy of MinGW.
Last updated: Nov 22 2024 at 17:03 UTC