x.py can't build individual crates

[jessicah]

I'm trying to test building just librustc_llvm for the purposes of git bisecting, but am getting the following error:

./x.py build --stage 1 src/librustc_llvm
Warning: no rules matched /home/jessicah/rust/src/librustc_llvm

[Mark-Simulacrum]

The logic in src/bootstrap/compile.rs needs to be include the crate being passed. Similar logic can be found in check.rs, specifically within make_run and during the build itself. Let me know if you need any assistance!

[rozuur]

can i work on this?

[tamird]

I took a look at this - it strikes me as not as easy as @Mark-Simulacrum's description.

TL;DR we need a type that implements Step whose should_run returns true when given a crate path. Then that type needs to be registered in this macro invocation.

It's possible this can be done by modifying an existing type, but I didn't find a suitable one.

[Mark-Simulacrum]

The logic will want to be similar to what is in test.rs:

rust/src/bootstrap/test.rs

Lines 1333 to 1344 in b7da1aa

	fn should_run(mut run: ShouldRun) -> ShouldRun {
	let builder = run.builder;
	run = run.krate("test");
	for krate in run.builder.in_tree_crates("std") {
	if krate.is_local(&run.builder) &&
	!krate.name.contains("jemalloc") &&
	!(krate.name.starts_with("rustc_") && krate.name.ends_with("san")) &&
	krate.name != "dlmalloc" {
	run = run.path(krate.local_path(&builder).to_str().unwrap());
	}
	}
	run

. Something like that should work for the compile steps, though we'd probably want to make sure the default is (unlike for tests) to build everything instead of a step-by-step build. This might be somewhat difficult to implement with the current design; I think it'd involve having the first call on run be something like path("default-path")...