download-ci-llvm does not include llvm-tblgen

[jyn514]

In particular, this means you have to rebuild llvm for the host when cross-compiling.

I tried this code: x build --host i686-unknown-linux-gnu.

I expected to see this happen: The compiler builds successfully.

Instead, this happened:

-- Build files have been written to: /home/joshua/rustc3/build/i686-unknown-linux-gnu/llvm/build
running: "cmake" "--build" "." "--target" "install" "--config" "Release" "--" "-j" "8"
ninja: error: '/home/joshua/rustc3/build/x86_64-unknown-linux-gnu/llvm/bin/llvm-tblgen', needed by 'include/llvm/IR/Attributes.inc', missing and no known rule to make it
thread 'main' panicked at '
command did not execute successfully, got: exit status: 1

build script failed, must exit now', /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/cmake-0.1.44/src/lib.rs:885:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
	finished in 8.264 seconds
failed to run: /home/joshua/rustc3/build/bootstrap/debug/bootstrap build --host i686-unknown-linux-gnu
Build completed unsuccessfully in 0:00:09

I think there's a secondary bug which is that x.py hard-codes llvm instead of ci-llvm/. But that seems easier to fix.

Meta

rustc --version --verbose:

<version>

Backtrace

<backtrace>

[jyn514]

Mentoring instructions:

1. Find where in src/bootstrap it generates the rust-dev component (I think I might be RustDev in dist.rs?)
2. Add llvm-tblgen to the binaries that are copied
3. Open a PR and ask someone to run @bors try, which will generate CI artifacts.
4. Checkout the merge commit from the try build locally and confirm that x build --host i686-unknown-linux-gnu works successfully (or if you're not on Linux, some other platform that's binary compatible).

[jyn514]

@rustbot label: +E-mentor

[bjorn3]

Add llvm-tblgen to the binaries that are copied

Make sure to only copy it if it exists. It doesn't get build if the llvm backend isn't enabled.

[cuviper]

Make sure to only copy it if it exists. It doesn't get build if the llvm backend isn't enabled.

It looks like RustDev unconditionally copies llvm binaries right now, so I think llvm-tblgen should be no different.

rust/src/bootstrap/dist.rs

Lines 2020 to 2033 in 43c22af

	for bin in &[
	"llvm-config",
	"llvm-ar",
	"llvm-objdump",
	"llvm-profdata",
	"llvm-bcanalyzer",
	"llvm-cov",
	"llvm-dwp",
	"llvm-nm",
	"llvm-dwarfdump",
	"llvm-dis",
	] {
	tarball.add_file(src_bindir.join(exe(bin, target)), "bin", 0o755);
	}