Use .drectve for MSVC DLL exports by AsakuraMizu · Pull Request #158294 · rust-lang/rust

AsakuraMizu · 2026-06-23T09:04:46Z

This is a continuation of #142568.

This fixes the i686 MSVC issue mentioned there: .def files accept undecorated names, but .drectve /EXPORT needs decorated symbol names. The public export name is preserved with EXPORTAS.

It's worth noting that EII with defaults now also works on MSVC.

rustbot · 2026-06-23T09:04:52Z

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AsakuraMizu · 2026-06-24T05:23:20Z

Updated :)

@rustbot ready

oli-obk

@bors r+ rollup

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rust-bors · 2026-06-24T15:22:04Z

📌 Commit 4051560 has been approved by oli-obk

It is now in the queue for this repository.

bjorn3 · 2026-06-24T16:11:27Z

Maybe rollup=iffy? Linkage related things tend to be tricky.

oli-obk · 2026-06-24T17:51:53Z

@bors rollup=iffy reason=windows linker shenanigans

…, r=oli-obk Use .drectve for MSVC DLL exports This is a continuation of rust-lang#142568. This fixes the i686 MSVC issue mentioned there: `.def` files accept undecorated names, but `.drectve` `/EXPORT` needs decorated symbol names. The public export name is preserved with `EXPORTAS`. It's worth noting that EII with defaults now also works on MSVC.

…uwer Rollup of 17 pull requests Successful merges: - #153697 (Add arg splat experiment initial tuple impl) - #158294 (Use .drectve for MSVC DLL exports) - #158253 (codegen_ssa: multiply scalable vec size by `vscale`) - #158308 (Fix bug when rustdoc "go to only result" setting is not working as expected") - #158345 (Use `transmute_neo` in `assume_init`) - #158369 (std: abort when `resume_unwind` is called inside the panic hook) - #158374 (disallow tail calling extern "rust-call" functions) - #158380 (Revert "rebuild LLVM when `bootstrap.toml` config changes") - #154398 (Add test for async Send with PhantomData<*mut ()> + unsafe impl Send + dyn Trait) - #157181 (autodiff: stop always needing an alloca) - #158278 (autodiff - typtree cleanups) - #158311 (doc(unstable-book): fix typo "earier" -> "earlier" in default-visibility flag) - #158318 (Make normalization in a test case resilient to dist compilation) - #158338 (Reorganize `tests/ui/issues` [14/N]) - #158343 (Include `Item::const_stability` info in rustdoc JSON.) - #158355 (Fixup the refactoring errors in #156246) - #158390 (Fix: auto trait, const trait bound) Failed merges: - #155535 (export symbols: support macos/windows(32/64))

JonathanBrouwer · 2026-06-25T10:18:41Z

💔 I suspect this PR failed tests as part of a rollup
@bors r-

After fixing the problem, consider running a try job for the failed job before re-approving.

Link to failure: #158391 (comment)

rust-bors · 2026-06-25T10:18:48Z

This pull request was unapproved.

This PR was contained in a rollup (#158391), which was unapproved.

View changes since this unapproval

rust-bors · 2026-06-29T17:18:01Z

💔 Test for 2523831 failed: CI. Failed job:

auto - x86_64-msvc-ext1 (web logs, enhanced plaintext logs)

oli-obk · 2026-06-30T05:17:13Z

@bors try jobs=x86_64-msvc-ext1

Use .drectve for MSVC DLL exports try-job: x86_64-msvc-ext1

rust-bors · 2026-06-30T07:32:18Z

☀️ Try build successful (CI)
Build commit: a558f27 (a558f2706edcfaa8ced9843b1d3addc791a7c012)
Base parent: 0966944 (096694416a41840709140eb0fd0ca193d1a3e6ba)

AsakuraMizu · 2026-06-30T07:42:37Z

It seems that if we don't pass a /DEF:lib.def, link.exe won't generate a .lib file for an empty cdylib. lld, on the other hand, doesn't have this problem.

@rustbot ready

rustbot · 2026-06-30T09:27:28Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

AsakuraMizu · 2026-07-01T05:33:14Z

@rustbot ready

bjorn3 · 2026-07-01T11:30:42Z

I think this PR allows replacing the //@ ignore-windows in all EII tests with //@ ignore-windows-gnu. Can be done in a follow up PR.

rustbot assigned oli-obk Jun 23, 2026

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JonathanBrouwer mentioned this pull request Jun 25, 2026

Rollup of 18 pull requests #158386

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Rollup of 17 pull requests #158389

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Rollup of 17 pull requests #158391

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Preserve MSVC import libs for empty cdylibs

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AsakuraMizu force-pushed the windows-drectve-export branch from c359042 to 2f749bd Compare June 30, 2026 05:10

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rust-bors Bot pushed a commit that referenced this pull request Jun 30, 2026

Auto merge of #158294 - AsakuraMizu:windows-drectve-export, r=<try>

a558f27

Use .drectve for MSVC DLL exports try-job: x86_64-msvc-ext1

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Rewrite dll-weak-definition test to run-make

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AsakuraMizu force-pushed the windows-drectve-export branch from d16908e to 296ba6a Compare July 1, 2026 03:59

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bjorn3 mentioned this pull request Jul 1, 2026

Use the .drectve section for exporting symbols from dlls on Windows #142568

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