Skip to content

Add alternative linker to the build performance guide #15991

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 2 commits into
base: master
Choose a base branch
from
Open

Add alternative linker to the build performance guide #15991

Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
d243960
Add alternative linker to the build performance guide
Kobzol Sep 20, 2025
f0a5f75
Clarify code generation vs build times benefits
Kobzol Sep 21, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 2 additions & 2 deletions src/doc/src/guide/build-performance.md
View file
Open in desktop
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This reminds maybe we should consider a cargo native lld option for build.linker: #11378.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

That might be nice indeed, but the situation with linkers is a bit complicated. You can use the self-contained LLD, or an external LLD, on Linux you invoke LLD through cc and -fuse-ld=lld, while elsewhere through -Clinker, if the linker is not lld, but something else unsupported by the CC driver, it cannot be specified by name, but has to be passed through some hacks with an absolute path.. it's quite messy.

Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,7 @@ This will:
- Provide an opt-in for when debugging via [`--profile debugging`](../reference/profiles.md#custom-profiles)

Trade-offs:
- ✅ Faster build times
- ✅ Faster code generation (`cargo build`)
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

imo that is too jargony without the surrounding context. When I see code generation, I think of the type of thing build scripts usually do

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Should I create some basic terminology at the start of the page, where we'll say that compilation is split into three categories (frontend, backend, codegen), and then we'll say in each mechanism which of these categories it helps?

- ✅ Faster link times
- ✅ Smaller disk usage of the `target` directory
- ❌ Requires a full rebuild to have a high-quality debugger experience
Expand Down Expand Up @@ -83,7 +83,7 @@ rustflags = "-Zthreads=8"
This [`rustflags`][build.rustflags] will enable the [parallel frontend][parallel-frontend-blog] of the Rust compiler, and tell it to use `n` threads. The value of `n` should be chosen according to the number of cores available on your system, although there are diminishing returns. We recommend using at most `8` threads.

Trade-offs:
- ✅ Faster build times
- ✅ Faster build times (both `cargo check` and `cargo build`)
- ❌ **Requires using nightly Rust and an [unstable Rust feature][parallel-frontend-issue]**

[parallel-frontend-blog]: https://blog.rust-lang.org/2023/11/09/parallel-rustc/
Expand Down
Loading