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bors e8a792daf5 Auto merge of #145645 - Kobzol:uplift-fix, r=jieyouxu
Fix rustc uplifting (take two)

The rustc uplifting logic is really annoying.. https://github.com/rust-lang/rust/pull/145557 was not enough to fix it.

Consider https://github.com/rust-lang/rust/issues/145534#issuecomment-3201868888: in this situation, we do a stage3 build of a cross-compiled rustc (it happens because we run `x test --stage 2`, which mistakenly builds a stage3 rustc, but it doesn't matter what casuses it, what matters is that the stage3 build isn't working).

Currently, a stage3 cross-compiled build of rustc works like this:
1) stage0 (host) -> stage1 (host)
2) stage1 (host) -> stage2 (host)
3) stage2 (host) -> stage3 (target)

The problem is that in the uplifting logic, I assumed that we will have a stage2 (target) rustc available, which we can uplift. And that would indeed be an ideal solution. But currently, we will actually build a stage2 (*host*) rustc, and only then start the cross-compilation. So the uplifting is broken.

I spend a couple of hours trying to fix this, and do the uplifting "from the other direction", so that already when we assemble a stage3 rustc, we notice that an uplift should happen, and we only build stage1 (host) rustc, which also helps avoid one needless rustc build. However, this was relatively complicated and would require larger changes that I was not confident landing at this time.

So instead I decided to do a much simpler fix, and just disable rustc uplifting when cross-compiling. Since we currently do the `stage2 (host) -> stage3 (target)` step, it should not actually affect stage3 cross-compiled builds in any way (I hope..), and should only affect stage4+ builds, about which I don't really care (the only change there should be more rustc builds). For normal builds, the stage2 host rustc should (hopefully) always be present, so we shouldn't run into this issue.

Eventually, I would like to remove rustc uplifting completely. However, `x test --stage 2` on CI still currently builds a stage3 rustc for some reason, and if we removed uplifting completely, even for non-cross-compiled builds, that would cause an additional rustc build, and that's not great. So for now let's just allow uplifting for non-cross-compiled builds.

Fixes rust-lang/rust#145534.

r? `@jieyouxu`
2025-08-20 12:10:34 +00:00
.github Rollup merge of #145311 - marcoieni:clean-disk-in-background-windows, r=Kobzol 2025-08-15 16:03:56 +02:00
compiler Auto merge of #145348 - nnethercote:parse_token_tree-speedup-for-uom, r=petrochenkov 2025-08-20 09:01:41 +00:00
library Rollup merge of #145626 - folkertdev:prefetch-fallback, r=Amanieu 2025-08-20 00:46:02 -04:00
LICENSES Synchronize Unicode license text from unicode.org 2024-11-20 00:54:12 -08:00
src Auto merge of #145645 - Kobzol:uplift-fix, r=jieyouxu 2025-08-20 12:10:34 +00:00
tests Rollup merge of #145626 - folkertdev:prefetch-fallback, r=Amanieu 2025-08-20 00:46:02 -04:00
.clang-format Add .clang-format 2024-06-26 05:56:00 +08:00
.editorconfig editorconfig: don't trim trailing whitespace in tests 2025-08-08 11:15:28 -05:00
.git-blame-ignore-revs git: ignore 60600a6fa4 for blame purposes 2025-04-17 11:50:24 +08:00
.gitattributes Mark .pp files as Rust 2025-03-29 12:39:06 +01:00
.gitignore tidy: use a lockfile for js tools instead of npx 2025-07-19 14:44:15 -05:00
.gitmodules Update to LLVM 21 2025-08-01 10:17:04 +02:00
.ignore change config.toml to bootstrap.toml for bootstrap module 2025-03-17 12:56:41 +05:30
.mailmap Add my previous commit name to .mailmap 2025-08-01 21:59:56 +02:00
bootstrap.example.toml Rollup merge of #145426 - AMS21:fix_typos_bootstrap_example, r=lqd 2025-08-15 16:04:00 +02:00
Cargo.lock rustdoc-search: search backend with partitioned suffix tree 2025-08-15 10:26:03 -07:00
Cargo.toml Bump Clippy version -> 0.1.91 2025-08-07 16:48:16 +02:00
CODE_OF_CONDUCT.md Remove the code of conduct; instead link https://www.rust-lang.org/conduct.html 2019-10-05 22:55:19 +02:00
configure Ensure ./configure works when configure.py path contains spaces 2024-02-16 18:57:22 +00:00
CONTRIBUTING.md Improve CONTRIBUTING.md grammar and clarity 2025-05-23 23:03:06 +02:00
COPYRIGHT dist: Re-work how we describe the licence of Rust in our distributions 2024-12-09 10:18:55 +00:00
INSTALL.md mention about x.py setup in INSTALL.md 2025-04-24 09:15:53 +03:00
LICENSE-APACHE Remove appendix from LICENCE-APACHE 2019-12-30 14:25:53 +00:00
license-metadata.json Update license metadata 2025-02-15 16:48:37 +01:00
LICENSE-MIT dist: Re-work how we describe the licence of Rust in our distributions 2024-12-09 10:18:55 +00:00
package-lock.json tidy: use a lockfile for js tools instead of npx 2025-07-19 14:44:15 -05:00
package.json tidy: use a lockfile for js tools instead of npx 2025-07-19 14:44:15 -05:00
README.md Update Rust Foundation links in Readme 2025-03-16 19:03:40 -07:00
RELEASES.md Add a few missed entries 2025-08-06 13:57:36 +01:00
REUSE.toml REUSE.toml: add new package.json and package-lock.json 2025-07-19 14:44:16 -05:00
rust-bors.toml Add approval blocking labels for new bors 2025-07-19 21:30:12 +02:00
rustfmt.toml Rename tests/codegen into tests/codegen-llvm 2025-07-22 14:28:48 +02:00
triagebot.toml Auto merge of #145601 - jieyouxu:rollup-t5mbqhc, r=jieyouxu 2025-08-19 23:52:06 +00:00
typos.toml typos: allow moreso 2025-08-16 13:36:29 -05:00
x Look for python3 first on MacOS, not py 2025-02-13 10:24:54 -05:00
x.ps1 use & instead of start-process in x.ps1 2023-12-09 09:46:16 -05:00
x.py Reformat Python code with ruff 2024-12-04 23:03:44 +01:00

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