Allow using self-contained LLD in bootstrap by Kobzol · Pull Request #135001 · rust-lang/rust (original) (raw)

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…ntained"` is used

Before, we just used the global lld anyway.

Not all targets support these flags, so we cannot just pass them to the tests unconditionally. Before, we were using a linker arg (-Clink-arg=-fuse-ld=lld), which circumvented this in a hacky way.

rustbot added S-waiting-on-review

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T-bootstrap

Relevant to the bootstrap subteam: Rust's build system (x.py and src/bootstrap)

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Jan 1, 2025

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Jan 3, 2025

bors added a commit to rust-lang-ci/rust that referenced this pull request

Jan 4, 2025

…iaskrgr

Rollup of 7 pull requests

Successful merges:

rust-lang#133964 (core: implement bool::select_unpredictable)
rust-lang#135001 (Allow using self-contained LLD in bootstrap)
rust-lang#135055 (Report impl method has stricter requirements even when RPITIT inference gets in the way)
rust-lang#135064 (const-in-pattern: test that the PartialEq impl does not need to be const)
rust-lang#135066 (bootstrap: support ./x check run-make-support)
rust-lang#135069 (remove unused function params)
rust-lang#135084 (Update carrying_mul_add test to tolerate nuw)

r? @ghost @rustbot modify labels: rollup

rust-timer added a commit to rust-lang-ci/rust that referenced this pull request

Jan 4, 2025

Rollup merge of rust-lang#135001 - Kobzol:bootstrap-mcp-510, r=onur-ozkan

Allow using self-contained LLD in bootstrap

In rust-lang#116278, I added a "self-contained" mode to the rust.use-lld bootstrap option, which was designed for using the built-in LLD for linking compiler artifacts. However, this was later reverted in rust-lang#118810.

This PR brings the old logic back, which switches LLD in bootstrap from -fuse-ld=lld to MCP510 way of passing linker flags to enable LLD (both external and self-contained). So this does two changes:

Goes from -fuse-ld=lld to MCP510
Actually makes it possible to use the self-contained LLD to compile compiler artifacts

Regarding the second commit: Since rust-lang#86113, we have been passing -fuse-ld=lld as a target flag to all tests when use-lld = true is enabled. This kind of worked for all tests, since it was just a linker argument, which has bypassed any compiler checks, and probably resulted only in some warning if the given target linker didn't actually support LLD. However, after the first commit, some tests actually start failing with this approach:

error: linker flavor `gnu-lld-cc` is incompatible with the current target
   |
   = note: compatible flavors are: llbc, ptx

So the second commit removes the passing of LLD flags as target flags to tests. I don't think that it's a good idea to pass specific compiler flags to all tests unconditionally, tbh. The doctest command from rust-lang#86113 doesn't go through compiletest anymore, and doctests should be quite a lot faster since rust-lang#126245 in general.

CC @the8472

If someone has a beefy machine, it would be nice to test whether this doesn't regress test execution speed. How to do that:

Enable rust.use-lld = true and rust.lld = true in config.toml
Benchmark ./x test tests/ui --force-rerun between master and this PR

Once this is tested in the wild, I would like to make the self-contained LLD the default in CI, hopefully to make CI builds faster.

r? @onur-ozkan

Kobzol deleted the bootstrap-mcp-510 branch

January 4, 2025 13:33

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matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request

Apr 4, 2025

…trochenkov

Use target-agnostic LLD flags in bootstrap for use-lld

Before, I hardcoded LLD flags that pretty much only worked on GNU. The right way is to use -Zlinker-features instead though.

I think that this should also make this work on Windows mingw, and thus @petrochenkov's workaround is no longer necessary.

Fixes: rust-lang#139372 Closes: rust-lang#139375

r? @lqd

rust-timer added a commit to rust-lang-ci/rust that referenced this pull request

Apr 5, 2025

Rollup merge of rust-lang#139378 - Kobzol:bootstrap-use-lld-fix, r=petrochenkov

Use target-agnostic LLD flags in bootstrap for use-lld

Before, I hardcoded LLD flags that pretty much only worked on GNU. The right way is to use -Zlinker-features instead though.

I think that this should also make this work on Windows mingw, and thus @petrochenkov's workaround is no longer necessary.

Fixes: rust-lang#139372 Closes: rust-lang#139375

r? @lqd