Emit retags in codegen to support BorrowSanitizer (part 1) by icmccorm · Pull Request #156208 · rust-lang/rust

icmccorm · 2026-05-05T21:27:12Z

This is the first of several PRs that will add experimental support for emitting retags as function calls in codegen. Each PR will be a minimal, improved slice of the changes in #155965.

This PR contains all of the changes that will affect codegen backends. It adds methods to IntrinsicCallBuilderMethods for emitting each kind of retag call.

cc: @RalfJung

rustbot · 2026-05-05T21:27:16Z

The GCC codegen subtree was changed

cc @antoyo, @GuillaumeGomez

rustbot · 2026-05-05T21:27:18Z

r? @jackh726

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saethlin · 2026-05-05T21:45:44Z

r? saethlin

rustbot · 2026-05-15T16:38:19Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

saethlin · 2026-05-17T02:39:56Z

@bors r+

rust-bors · 2026-05-17T02:39:59Z

📌 Commit e15861b has been approved by saethlin

It is now in the queue for this repository.

@RalfJung

…-1, r=saethlin Emit retags in codegen to support BorrowSanitizer (part 1) Tracking issue: rust-lang#154760 [Zulip Thread](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Staging.20for.20emitting.20retags.20in.20codegen/with/593004012) This is the first of several PRs that will add experimental support for emitting retags as function calls in codegen. Each PR will be a minimal, improved slice of the changes in rust-lang#155965. This PR contains all of the changes that will affect codegen backends. It adds methods to `IntrinsicCallBuilderMethods` for emitting each kind of retag call. cc: @RalfJung

JonathanBrouwer · 2026-05-17T12:25:52Z

@bors try jobs=aarch64-apple

rust-bors · 2026-05-17T12:25:58Z

⌛ Trying commit e15861b with merge e6b753f…

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

Workflow: https://github.com/rust-lang/rust/actions/runs/25990798832

Emit retags in codegen to support BorrowSanitizer (part 1) try-job: aarch64-apple

JonathanBrouwer · 2026-05-17T13:51:23Z

@bors try cancel

rust-bors · 2026-05-17T13:51:27Z

Try build cancelled. Cancelled workflows:

https://github.com/rust-lang/rust/actions/runs/25990798832

…uwer Rollup of 14 pull requests Successful merges: - #151742 (Remove redundant information in `rustc_abi::Variants`) - #151362 (Add interior-mutability suggestion to `static_mut_refs`) - #156121 (compiler: suggest `.collect()` when `String` is expected and `Iterator` is found) - #156208 (Emit retags in codegen to support BorrowSanitizer (part 1)) - #156596 (Split `LintExpectationId`s) - #156607 (ci: Update FreeBSD version to FreeBSD 14) - #156376 (suggest hex escapes for C-style escapes) - #156577 (Test EII UI tests with prefer-dynamic) - #156585 (explicit tail calls: ignore some tests on unsupported LLVM targets) - #156598 (Avoid rustfix suggestions for macro-expanded unused imports) - #156616 (rustdoc: add test case for `-Drustdoc::` and `--cap-lints`) - #156633 (Add regression test for issue #41261) - #156635 (rename unexpected_try_recover function) - #156636 (minor `rustc_mir_transform` cleanup)

@RalfJung

Rollup merge of #156208 - BorrowSanitizer:codegen-emit-retag-1, r=saethlin Emit retags in codegen to support BorrowSanitizer (part 1) Tracking issue: #154760 [Zulip Thread](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Staging.20for.20emitting.20retags.20in.20codegen/with/593004012) This is the first of several PRs that will add experimental support for emitting retags as function calls in codegen. Each PR will be a minimal, improved slice of the changes in #155965. This PR contains all of the changes that will affect codegen backends. It adds methods to `IntrinsicCallBuilderMethods` for emitting each kind of retag call. cc: @RalfJung

…uwer Rollup of 14 pull requests Successful merges: - rust-lang/rust#151742 (Remove redundant information in `rustc_abi::Variants`) - rust-lang/rust#151362 (Add interior-mutability suggestion to `static_mut_refs`) - rust-lang/rust#156121 (compiler: suggest `.collect()` when `String` is expected and `Iterator` is found) - rust-lang/rust#156208 (Emit retags in codegen to support BorrowSanitizer (part 1)) - rust-lang/rust#156596 (Split `LintExpectationId`s) - rust-lang/rust#156607 (ci: Update FreeBSD version to FreeBSD 14) - rust-lang/rust#156376 (suggest hex escapes for C-style escapes) - rust-lang/rust#156577 (Test EII UI tests with prefer-dynamic) - rust-lang/rust#156585 (explicit tail calls: ignore some tests on unsupported LLVM targets) - rust-lang/rust#156598 (Avoid rustfix suggestions for macro-expanded unused imports) - rust-lang/rust#156616 (rustdoc: add test case for `-Drustdoc::` and `--cap-lints`) - rust-lang/rust#156633 (Add regression test for issue rust-lang/rust#41261) - rust-lang/rust#156635 (rename unexpected_try_recover function) - rust-lang/rust#156636 (minor `rustc_mir_transform` cleanup)

@RalfJung

…-2, r=saethlin Emit retags in codegen to support BorrowSanitizer (part 2) Tracking issue: rust-lang#154760 [Zulip Thread](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Staging.20for.20emitting.20retags.20in.20codegen/with/593004012) This is one of several PRs that will add experimental support for emitting retags as function calls in codegen. Each PR will be a minimal, improved slice of the changes in rust-lang#155965. This PR adds a new unstable flag `-Zcodegen-emit-retag`, which will enable experimental retag calls in generated code. This flag is a nop for now, but the relevant methods have been added to codegen_ssa, and they are called wherever retags are necessary. Subsequent PRs will complete this implementation. This does not depend on rust-lang#156208. r? @RalfJung

@RalfJung

Emit retags in codegen to support BorrowSanitizer (part 2) Tracking issue: #154760 [Zulip Thread](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Staging.20for.20emitting.20retags.20in.20codegen/with/593004012) This is one of several PRs that will add experimental support for emitting retags as function calls in codegen. Each PR will be a minimal, improved slice of the changes in #155965. This PR adds a new unstable flag `-Zcodegen-emit-retag`, which will enable experimental retag calls in generated code. This flag is a nop for now, but the relevant methods have been added to codegen_ssa, and they are called wherever retags are necessary. Subsequent PRs will complete this implementation. This does not depend on #156208. r? @RalfJung

@RalfJung

Rollup merge of #156210 - BorrowSanitizer:codegen-emit-retag-2, r=saethlin Emit retags in codegen to support BorrowSanitizer (part 2) Tracking issue: #154760 [Zulip Thread](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Staging.20for.20emitting.20retags.20in.20codegen/with/593004012) This is one of several PRs that will add experimental support for emitting retags as function calls in codegen. Each PR will be a minimal, improved slice of the changes in #155965. This PR adds a new unstable flag `-Zcodegen-emit-retag`, which will enable experimental retag calls in generated code. This flag is a nop for now, but the relevant methods have been added to codegen_ssa, and they are called wherever retags are necessary. Subsequent PRs will complete this implementation. This does not depend on #156208. r? @RalfJung

@RalfJung

…-3, r=saethlin Emit retags in codegen to support BorrowSanitizer (part 3) Tracking issue: rust-lang#154760 [Zulip Thread](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Staging.20for.20emitting.20retags.20in.20codegen/with/593004012) This is one of several PRs that will add experimental support for emitting retags as function calls in codegen. This PR adds `RetagPlan`, which describes where the pointers that need to be retagged live within the layout of a type. We create a `RetagPlan` ahead of time because only a subset of the variants of a type might contain retagable values. We only want to branch to these variants, and ignore all of the others. If a type can generate a `RetagPlan`, then we will use it as a guide for inserting calls to our retag intrinsics. If a type does not generate a `RetagPlan`, then it does not need to be retagged, and we can skip it. This does not emit a `RetagPlan::EmitRetag` yet. That will come in a subsequent PR. Previous parts: rust-lang#156208, rust-lang#156210 cc: @RalfJung r? @saethlin

@RalfJung

Rollup merge of #157825 - BorrowSanitizer:codegen-emit-retag-3, r=saethlin Emit retags in codegen to support BorrowSanitizer (part 3) Tracking issue: #154760 [Zulip Thread](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Staging.20for.20emitting.20retags.20in.20codegen/with/593004012) This is one of several PRs that will add experimental support for emitting retags as function calls in codegen. This PR adds `RetagPlan`, which describes where the pointers that need to be retagged live within the layout of a type. We create a `RetagPlan` ahead of time because only a subset of the variants of a type might contain retagable values. We only want to branch to these variants, and ignore all of the others. If a type can generate a `RetagPlan`, then we will use it as a guide for inserting calls to our retag intrinsics. If a type does not generate a `RetagPlan`, then it does not need to be retagged, and we can skip it. This does not emit a `RetagPlan::EmitRetag` yet. That will come in a subsequent PR. Previous parts: #156208, #156210 cc: @RalfJung r? @saethlin

@RalfJung

…-4, r=saethlin Emit retags in codegen to support BorrowSanitizer (part 4) Tracking issue: rust-lang#154760 [Zulip Thread](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Staging.20for.20emitting.20retags.20in.20codegen/with/593004012) This is one of several PRs that add experimental support for emitting retags as function calls in codegen. This PR emits our retag intrinsics based on the structure of a `RetagPlan`. The feature works end-to-end now! But, it has two limitations: * We do not track interior mutable or pinned ranges precisely. This will come in the next PR, which should be the last one that we need to complete this feature (excluding documentation and compile tests). * We recurse into `repr(simd)` types when building a `RetagPlan`, but we do not emit retags for their fields. We would need `BuilderMethods::insert_element`, which isn't available. I'm not sure what the best workaround would be for this. Related: rust-lang#157825, rust-lang#156210, rust-lang#156208 Cc: @RalfJung r? @saethlin

rustbot assigned jackh726 May 5, 2026

icmccorm mentioned this pull request May 5, 2026

Emit retags in codegen to support BorrowSanitizer (part 2) #156210

Merged

rustbot assigned saethlin and unassigned jackh726 May 5, 2026

Add trait methods for experimental retags to cg.

e15861b

icmccorm force-pushed the codegen-emit-retag-1 branch from 824ce42 to e15861b Compare May 15, 2026 16:38

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 May 17, 2026

JonathanBrouwer mentioned this pull request May 17, 2026

Rollup of 11 pull requests #156658

Closed

rust-bors Bot pushed a commit that referenced this pull request May 17, 2026

Auto merge of #156208 - BorrowSanitizer:codegen-emit-retag-1, r=<try>

e6b753f

Emit retags in codegen to support BorrowSanitizer (part 1) try-job: aarch64-apple

JonathanBrouwer mentioned this pull request May 17, 2026

Rollup of 14 pull requests #156670

Merged

rust-bors Bot merged commit ff42fc0 into rust-lang:main May 18, 2026
11 of 12 checks passed

icmccorm mentioned this pull request May 18, 2026

Interop Safety: Improving cross-language analysis by augmenting LLVM IR with Rust type information rust-lang/all-hands-2026#26

Open

ehuss added this to the 1.97.0 milestone May 28, 2026

icmccorm mentioned this pull request May 30, 2026

BorrowSanitizer rust-lang/rust-project-goals#624

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icmccorm deleted the codegen-emit-retag-1 branch June 7, 2026 21:12

icmccorm mentioned this pull request Jun 12, 2026

Emit retags in codegen to support BorrowSanitizer (part 3) #157825

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icmccorm mentioned this pull request Jun 18, 2026

Emit retags in codegen to support BorrowSanitizer (part 4) #158100

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Emit retags in codegen to support BorrowSanitizer (part 1)#156208

Emit retags in codegen to support BorrowSanitizer (part 1)#156208
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