Switch TLS implementation for wasi and bump SDK version to 34 by maxdexh · Pull Request #163809 · rust-lang/rust

maxdexh · 2026-10-05T13:49:47Z

Effectively reverts #160868 to unrevert the changes to wasi from #159733.

As explained in #160868, now that we use wasi-sdk-34 (since #161773), the bug in wasi-libc that motivated the workaround should no longer be an issue.

To reflect the fact that we're now relying on version 34, I've also adjusted the minimum SDK version mentioned in the target docs.

Note: This could probably be backported to beta, but as this is only a tier 2 target, and 1.99 is already affected by the issue, I don't think this is necessary.

cc @alexcrichton
r? @clarfonthey

alexcrichton · 2026-10-05T14:53:28Z

lgtm, thanks! (don't want to steal r+ tho)

maxdexh · 2026-10-05T14:58:16Z

Don't want or can't? The only reason I didn't r? you was that I thought you're not allowed to merge libs changes ^^

clarfonthey · 2026-10-06T02:06:45Z

Alex isn't on the libs team but he does have r+ privileges and is a WASI target maintainer so I'm fine trusting his judgement here. (Even though, as stated, he isn't the maintainer for this WASI target.)

@bors r+ rollup

rust-bors · 2026-10-06T02:06:48Z

📌 Commit 341977a has been approved by clarfonthey

It is now in the queue for this repository.

clarfonthey · 2026-10-06T02:07:14Z

@bors r=alexcrichton,clarfonthey

rust-bors · 2026-10-06T02:07:17Z

📌 Commit 341977a has been approved by alexcrichton,clarfonthey

It is now in the queue for this repository.

clarfonthey · 2026-10-06T02:09:17Z

@rustbot label:beta-nominated

Don't think we're doing a 1.99.1 release, but cc @rust-lang/release just in case they are and want to stable backport.

tgross35 · 2026-10-06T02:29:43Z

Do we have a test for this somewhere? WASI is not currently tested in CI but I believe that was proposed for the near future.

rust-bors · 2026-10-06T04:22:23Z

⌛ Testing commit 341977a with merge 739f332...

Workflow: https://github.com/rust-lang/rust/actions/runs/37413395042

@alexcrichton

…arfonthey Adjust the adjustment to wasi TLS to no longer adjust Fixes #163748 Effectively reverts #160868 to unrevert the changes to wasi from #159733. As explained in #160868, now that we use wasi-sdk-34 (since #161773), the bug in wasi-libc that motivated the workaround should no longer be an issue. To reflect the fact that we're now relying on version 34, I've also adjusted the minimum SDK version mentioned in the target docs. Note: This could probably be backported to beta, but as this is only a tier 2 target, and 1.99 is already affected by the issue, I don't think this is necessary. cc @alexcrichton r? @clarfonthey

@alexcrichton

…crichton,clarfonthey Adjust the adjustment to wasi TLS to no longer adjust Fixes rust-lang#163748 Effectively reverts rust-lang#160868 to unrevert the changes to wasi from rust-lang#159733. As explained in rust-lang#160868, now that we use wasi-sdk-34 (since rust-lang#161773), the bug in wasi-libc that motivated the workaround should no longer be an issue. To reflect the fact that we're now relying on version 34, I've also adjusted the minimum SDK version mentioned in the target docs. Note: This could probably be backported to beta, but as this is only a tier 2 target, and 1.99 is already affected by the issue, I don't think this is necessary. cc @alexcrichton r? @clarfonthey

jhpratt · 2026-10-06T04:32:27Z

@bors yield to rollup

rust-bors · 2026-10-06T04:32:30Z

Auto build was cancelled. Cancelled workflows:

https://github.com/rust-lang/rust/actions/runs/37413395042

The next pull request likely to be tested is #163858.

Rollup of 3 pull requests Successful merges: - #163809 (Adjust the adjustment to wasi TLS to no longer adjust) - #163348 (perf:cache FFI safety results in improper_ctypes lint) - #163772 (comptime fn error: suggest wrapping in const block)

@alexcrichton

…crichton,clarfonthey Adjust the adjustment to wasi TLS to no longer adjust Fixes rust-lang#163748 Effectively reverts rust-lang#160868 to unrevert the changes to wasi from rust-lang#159733. As explained in rust-lang#160868, now that we use wasi-sdk-34 (since rust-lang#161773), the bug in wasi-libc that motivated the workaround should no longer be an issue. To reflect the fact that we're now relying on version 34, I've also adjusted the minimum SDK version mentioned in the target docs. Note: This could probably be backported to beta, but as this is only a tier 2 target, and 1.99 is already affected by the issue, I don't think this is necessary. cc @alexcrichton r? @clarfonthey

Rollup of 2 pull requests Successful merges: - #163348 (perf:cache FFI safety results in improper_ctypes lint) - #163809 (Adjust the adjustment to wasi TLS to no longer adjust)

maxdexh · 2026-10-06T06:48:52Z

Do we have a test for this somewhere? WASI is not currently tested in CI but I believe that was proposed for the near future.

I think you answered your own question there ^^

As stated in the platform docs, tier 2 is "guaranteed to build", tier 1 is "guaranteed to work" :D

tgross35 · 2026-10-06T07:07:20Z

I didn’t mean WASI-specific though, was referring to a test for this kind of destructor behavior. Which would start getting run when/if WASI is tested in CI, but still cover other platforms and local runs until then.

@alexcrichton

…crichton,clarfonthey Adjust the adjustment to wasi TLS to no longer adjust Fixes rust-lang#163748 Effectively reverts rust-lang#160868 to unrevert the changes to wasi from rust-lang#159733. As explained in rust-lang#160868, now that we use wasi-sdk-34 (since rust-lang#161773), the bug in wasi-libc that motivated the workaround should no longer be an issue. To reflect the fact that we're now relying on version 34, I've also adjusted the minimum SDK version mentioned in the target docs. Note: This could probably be backported to beta, but as this is only a tier 2 target, and 1.99 is already affected by the issue, I don't think this is necessary. cc @alexcrichton r? @clarfonthey

alexcrichton · 2026-10-06T16:34:25Z

Oh, a caveat on this -- this shouldn't be backported to stable 1.99 because this change requires wasi-sdk-34 which is first present on current beta, 1.100

@bors r+

Otherwise though yeah it's fine to tweak that number

rust-bors · 2026-10-06T16:34:29Z

📌 Commit 87ec21a has been approved by alexcrichton

It is now in the queue for this repository.

maxdexh · 2026-10-06T16:43:30Z

Oh, a caveat on this -- this shouldn't be backported to stable 1.99 because this change requires wasi-sdk-34 which is first present on current beta, 1.100

yeah I pointed this out on zulip too, but ig we're ignoring that? Compat notes in a dot release seems like a bad idea.

clarfonthey · 2026-10-06T17:08:47Z

So, is the SDK bump required, or not?

Because I guess the issue is that putting compat notes on the release is… the release broke things anyway, so, aren't the compat notes just the ones that should have been on the original release?

I guess if you didn't use TLS that's an issue.

maxdexh · 2026-10-06T17:12:14Z

See zulip. Users still on sdk 33 will run into #160828 (which i think is worse than destructors not running) if we Backport this, assuming that it works at all

rustbot · 2026-10-06T17:16:58Z

stable backport declined as per libs team on Zulip.

@alexcrichton

…crichton Switch TLS implementation for wasi and bump SDK version to 34 Fixes rust-lang#163748 Effectively reverts rust-lang#160868 to unrevert the changes to wasi from rust-lang#159733. As explained in rust-lang#160868, now that we use wasi-sdk-34 (since rust-lang#161773), the bug in wasi-libc that motivated the workaround should no longer be an issue. To reflect the fact that we're now relying on version 34, I've also adjusted the minimum SDK version mentioned in the target docs. Note: This could probably be backported to beta, but as this is only a tier 2 target, and 1.99 is already affected by the issue, I don't think this is necessary. cc @alexcrichton r? @clarfonthey

…uwer Rollup of 25 pull requests Successful merges: - #163090 (Run LLDB debuginfo tests on `x86_64-pc-windows-msvc` in CI) - #163806 (even more `tests/crashes` migration for `-Znext-solver`) - #162156 (add IBM f128 type) - #163508 (Document the `rustc_on_unimplemented` attribute.) - #163794 (Use `target_family = "wasm"` instead of `target_arch = "wasm32"`) - #163863 (use the type name instead of `Self` in constructor paths again) - #163864 (Remove CLAUDE.md) - #163877 (Add regression test for duplicated rustdoc search results between std and core) - #163916 (Shrink `PartialRes` and its alignment) - #149753 (On name resolution error in parameter list, suggest possible `const` typo and avoid unnecessary second error) - #152557 (Oneshot `is_ready`) - #157273 (Stabilize `optimize` attribute) - #162000 (peel_transparent_wrappers only works on non-1ZST) - #163257 (abby DSL: sanity checks on forall where clauses) - #163343 (`unit` and `[1 x unit]` layouts are incompatible on big-endian targets) - #163348 (perf:cache FFI safety results in improper_ctypes lint) - #163768 (Move more `rustdoc-html` tests in the right location) - #163778 (check is_indirect_first_projection when replacing in RefProp) - #163789 (cg_llvm: Avoid `as_c_char_ptr` in several places) - #163807 (Add `has_reliable_f16b` for Arm) - #163809 (Switch TLS implementation for wasi and bump SDK version to 34) - #163826 (Update books) - #163849 (ci: update to PowerShell 7.6.6) - #163869 (INSTALL.md: use UCRT64 instead of MINGW64 in MSYS2 section) - #163870 (Add if-installed:auto:spellcheck to pre-push script)

@alexcrichton

…crichton Switch TLS implementation for wasi and bump SDK version to 34 Fixes rust-lang#163748 Effectively reverts rust-lang#160868 to unrevert the changes to wasi from rust-lang#159733. As explained in rust-lang#160868, now that we use wasi-sdk-34 (since rust-lang#161773), the bug in wasi-libc that motivated the workaround should no longer be an issue. To reflect the fact that we're now relying on version 34, I've also adjusted the minimum SDK version mentioned in the target docs. Note: This could probably be backported to beta, but as this is only a tier 2 target, and 1.99 is already affected by the issue, I don't think this is necessary. cc @alexcrichton r? @clarfonthey

…uwer Rollup of 24 pull requests Successful merges: - #163090 (Run LLDB debuginfo tests on `x86_64-pc-windows-msvc` in CI) - #163806 (even more `tests/crashes` migration for `-Znext-solver`) - #163508 (Document the `rustc_on_unimplemented` attribute.) - #163794 (Use `target_family = "wasm"` instead of `target_arch = "wasm32"`) - #163863 (use the type name instead of `Self` in constructor paths again) - #163864 (Remove CLAUDE.md) - #163877 (Add regression test for duplicated rustdoc search results between std and core) - #163916 (Shrink `PartialRes` and its alignment) - #149753 (On name resolution error in parameter list, suggest possible `const` typo and avoid unnecessary second error) - #152557 (Oneshot `is_ready`) - #157273 (Stabilize `optimize` attribute) - #162000 (peel_transparent_wrappers only works on non-1ZST) - #163257 (abby DSL: sanity checks on forall where clauses) - #163343 (`unit` and `[1 x unit]` layouts are incompatible on big-endian targets) - #163348 (perf:cache FFI safety results in improper_ctypes lint) - #163768 (Move more `rustdoc-html` tests in the right location) - #163778 (check is_indirect_first_projection when replacing in RefProp) - #163789 (cg_llvm: Avoid `as_c_char_ptr` in several places) - #163807 (Add `has_reliable_f16b` for Arm) - #163809 (Switch TLS implementation for wasi and bump SDK version to 34) - #163826 (Update books) - #163849 (ci: update to PowerShell 7.6.6) - #163869 (INSTALL.md: use UCRT64 instead of MINGW64 in MSYS2 section) - #163870 (Add if-installed:auto:spellcheck to pre-push script)

…uwer Rollup of 23 pull requests Successful merges: - #163090 (Run LLDB debuginfo tests on `x86_64-pc-windows-msvc` in CI) - #163806 (even more `tests/crashes` migration for `-Znext-solver`) - #163508 (Document the `rustc_on_unimplemented` attribute.) - #163794 (Use `target_family = "wasm"` instead of `target_arch = "wasm32"`) - #163863 (use the type name instead of `Self` in constructor paths again) - #163864 (Remove CLAUDE.md) - #163877 (Add regression test for duplicated rustdoc search results between std and core) - #163916 (Shrink `PartialRes` and its alignment) - #149753 (On name resolution error in parameter list, suggest possible `const` typo and avoid unnecessary second error) - #152557 (Oneshot `is_ready`) - #157273 (Stabilize `optimize` attribute) - #162000 (peel_transparent_wrappers only works on non-1ZST) - #163343 (`unit` and `[1 x unit]` layouts are incompatible on big-endian targets) - #163348 (perf:cache FFI safety results in improper_ctypes lint) - #163768 (Move more `rustdoc-html` tests in the right location) - #163778 (check is_indirect_first_projection when replacing in RefProp) - #163789 (cg_llvm: Avoid `as_c_char_ptr` in several places) - #163807 (Add `has_reliable_f16b` for Arm) - #163809 (Switch TLS implementation for wasi and bump SDK version to 34) - #163826 (Update books) - #163849 (ci: update to PowerShell 7.6.6) - #163869 (INSTALL.md: use UCRT64 instead of MINGW64 in MSYS2 section) - #163870 (Add if-installed:auto:spellcheck to pre-push script)

@alexcrichton

Rollup merge of #163809 - maxdexh:destroy-the-locals, r=alexcrichton Switch TLS implementation for wasi and bump SDK version to 34 Fixes #163748 Effectively reverts #160868 to unrevert the changes to wasi from #159733. As explained in #160868, now that we use wasi-sdk-34 (since #161773), the bug in wasi-libc that motivated the workaround should no longer be an issue. To reflect the fact that we're now relying on version 34, I've also adjusted the minimum SDK version mentioned in the target docs. Note: This could probably be backported to beta, but as this is only a tier 2 target, and 1.99 is already affected by the issue, I don't think this is necessary. cc @alexcrichton r? @clarfonthey

rust-timer · 2026-10-08T09:32:23Z

Note

This PR was benchmarked as part of triage of its containing rollup: triage URL.

Finished benchmarking commit (8c1fed7): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	1
Improvements ✅ (primary)	-0.1%	[-0.2%, -0.1%]	4
Improvements ✅ (secondary)	-0.2%	[-0.5%, -0.1%]	15
All ❌✅ (primary)	-0.1%	[-0.2%, -0.1%]	4

Max RSS (memory usage)

Results (secondary -2.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.1%	[-2.1%, -2.1%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 24.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	24.7%	[23.0%, 26.4%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

This perf run didn't have relevant results for this metric.

Artifact size: 408.59 MiB -> 408.70 MiB (0.03%)

JonathanBrouwer · 2026-10-08T16:22:51Z

This is noise, all PRs in the rollup have the same results

rustbot assigned clarfonthey Oct 5, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Oct 5, 2026

maxdexh requested a review from alexcrichton October 5, 2026 13:51

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 6, 2026

rustbot added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Oct 6, 2026

theemathas added the stable-nominated Nominated for backporting to the compiler in the stable channel. label Oct 6, 2026

jhpratt mentioned this pull request Oct 6, 2026

Rollup of 3 pull requests #163858

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Rollup of 2 pull requests #163859

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Rollup of 6 pull requests #163873

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rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Oct 6, 2026

rustbot removed stable-nominated Nominated for backporting to the compiler in the stable channel. stable-accepted Accepted for backporting to the compiler in the stable channel. labels Oct 6, 2026

JonathanBrouwer mentioned this pull request Oct 7, 2026

Rollup of 25 pull requests #163919

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Rollup of 24 pull requests #163934

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Rollup of 23 pull requests #163957

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rust-bors Bot merged commit e43cbac into rust-lang:main Oct 8, 2026
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rustbot added this to the 1.101.0 milestone Oct 8, 2026

clarfonthey added the relnotes Marks issues that should be documented in the release notes of the next release. label Oct 8, 2026

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Tracking issue for release notes of #163809: Switch TLS implementation for wasi and bump SDK version to 34 #163967

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maxdexh deleted the destroy-the-locals branch October 8, 2026 09:47

github-actions Bot mentioned this pull request Oct 9, 2026

Toolchain upgrade to nightly-2026-10-09 flux-rs/flux#1811

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