Use the in-tree `compiler-builtins` for the sysroot #141993

tgross35 · 2025-06-04T00:19:49Z

Many of std's dependency have a dependency on the crates.io compiler-builtins when used with the feature rustc-std-workspace-core. Use a Cargo patch to select the in-tree version instead.

compiler-builtins is also added as a dependency of rustc-std-workspace-core so these crates can remove their crates.io dependency in the future.

Zulip discussion: #t-compiler > Using in-tree compiler-builtins

Once this merges, the following PRs will need to make it to a release for the relevant crates:

Bump unicode-width to 0.2.0 getopts#119 (can merge at any time) released in v0.2.23
Remove optional dependency on compiler-builtins hashbrown#625 (can merge at any time) released in v0.15.4
Remove compiler-builtins from rustc-dep-of-std dependencies stdarch#1825
Remove compiler-builtins from rustc-dep-of-std dependencies rustc-demangle#80
Remove compiler-builtins from rustc-dep-of-std dependencies cfg-if#84
Remove compiler-builtins from rustc-dep-of-std dependencies unicode-rs/unicode-width#77

The above should cover all tier 1 targets with no std features enabled. The remaining cover the rest:

try-job: x86_64-gnu
try-job: test-various

compiler/rustc_metadata/src/creader.rs

library/compiler-builtins/compiler-builtins/Cargo.toml

WIP: Use the in-tree compiler-builtins for the sysroot Zulip discussion: [#t-compiler > Using in-tree compiler-builtins](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Using.20in-tree.20compiler-builtins/with/522445336) try-job: x86_64-gnu try-job: test-various

WIP: Use the in-tree compiler-builtins for the sysroot Many of `std`'s dependency have a dependency on the crates.io `compiler-builtins` when used with the feature `rustc-std-workspace-core`. Use a Cargo patch to select the in-tree version instead. `compiler-builtins` is also added as a dependency of `rustc-std-workspace-core` so these crates can remove their crates.io dependency in the future. Zulip discussion: [#t-compiler > Using in-tree compiler-builtins](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Using.20in-tree.20compiler-builtins/with/522445336) try-job: x86_64-gnu try-job: x86_64-gnu-aux try-job: test-various

tgross35 · 2025-06-04T22:30:27Z

I believe this works now. The first two commits are cherry picks that I will drop once #142036 merges.

r? @bjorn3

The `build.rs` entrypoint returns early for some targets, so emscripten and OpenBSD were not getting check-cfg set. Emit these earlier to avoid the `unexpected_cfgs` lint.

tgross35 · 2025-06-09T04:47:42Z

@bors2 try jobs=*various*

rust-bors · 2025-06-09T04:47:46Z

⌛ Trying commit fc71544 with merge fdbd817…

To cancel the try build, run the command @bors2 try cancel.

Use the in-tree `compiler-builtins` for the sysroot Many of `std`'s dependency have a dependency on the crates.io `compiler-builtins` when used with the feature `rustc-std-workspace-core`. Use a Cargo patch to select the in-tree version instead. `compiler-builtins` is also added as a dependency of `rustc-std-workspace-core` so these crates can remove their crates.io dependency in the future. Zulip discussion: [#t-compiler > Using in-tree compiler-builtins](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Using.20in-tree.20compiler-builtins/with/522445336) Once this merges, the following PRs will need to make it to a release for the relevant crates: - rust-lang/getopts#119 (can merge at any time) - rust-lang/hashbrown#625 (can merge at any time) - rust-lang/stdarch#1825 - rust-lang/rustc-demangle#80 - rust-lang/cfg-if#84 - unicode-rs/unicode-width#77 The above should cover all tier 1 targets with no `std` features enabled. The remaining cover the rest: - alexcrichton/dlmalloc-rs#50 (wasm, xous, sgx) - gimli-rs/gimli#769 - r-efi/r-efi#89 (efi) - r-efi/r-efi-alloc#9 (efi) - fortanix/rust-sgx#770 (sgx) - hermit-os/hermit-rs#718 (hermit) - bytecodealliance/wasi-rs#108 (wasi) - gimli-rs/addr2line#345 - oyvindln/adler2#2 - BurntSushi/memchr#180 - Frommi/miniz_oxide#173 - gimli-rs/object#777 try-job: x86_64-gnu try-job: test-various try-job: `*various*`

rust-bors · 2025-06-09T07:05:40Z

☀️ Try build successful (CI)
Build commit: fdbd817 (fdbd817613720a9898edca037a613559e7090b4b)

tgross35 · 2025-06-09T07:07:46Z

Two small lint-related fixes on targets that aren't tested in compiler-builtins CI. I also locally checked that compiler-builtins builds without warning on all of rustc --print target-list.

@bors r=bjorn3

bors · 2025-06-09T07:07:49Z

📌 Commit fc71544 has been approved by bjorn3

It is now in the queue for this repository.