std: include dlmalloc for all non-wasi Wasm targets#153686
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rust-bors[bot] merged 2 commits intorust-lang:mainfrom Mar 23, 2026
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std: include dlmalloc for all non-wasi Wasm targets#153686rust-bors[bot] merged 2 commits intorust-lang:mainfrom
std: include dlmalloc for all non-wasi Wasm targets#153686rust-bors[bot] merged 2 commits intorust-lang:mainfrom
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Currently, building std for a custom Wasm target with an OS other than `unknown` will fail, because `sys/alloc/mod.rs` will attempt to use `sys/alloc/wasm.rs`, the dlmalloc-based allocator used on `wasm32-unknown-unknown`. However, currently dlmalloc is only pulled in when `target_os = "unknown"`. Instead, we should make `Cargo.toml` and `alloc/mod.rs` match: either - disable `wasm.rs` in `alloc/mod.rs` where `not(target_os = "unknown")`, or - pull in `dlmalloc` for all Wasm targets with `target_family = "wasm32"` that aren't covered by the [upper branches of `alloc/mod.rs`](https://github.com/rust-lang/rust/blob/main/library/std/src/sys/alloc/mod.rs#L72-L100). This PR takes the latter approach, because it allows more code to compile without a custom allocator.
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`std`: include `dlmalloc` for all non-wasi Wasm targets Currently, building std for a custom Wasm target with an OS other than `unknown` will fail, because `sys/alloc/mod.rs` will attempt to use `sys/alloc/wasm.rs`, the dlmalloc-based allocator used on `wasm32-unknown-unknown`. However, currently dlmalloc is only pulled in when `target_os = "unknown"`. Instead, we should make `Cargo.toml` and `alloc/mod.rs` match: either - disable `wasm.rs` in `alloc/mod.rs` where `not(target_os = "unknown")`, or - pull in `dlmalloc` for all Wasm targets with `target_family = "wasm32"` that aren't covered by the [upper branches of `alloc/mod.rs`](https://github.com/rust-lang/rust/blob/main/library/std/src/sys/alloc/mod.rs#L72-L100). This PR takes the latter approach, because it allows more code to compile without a custom allocator.
JonathanBrouwer
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Mar 22, 2026
`std`: include `dlmalloc` for all non-wasi Wasm targets Currently, building std for a custom Wasm target with an OS other than `unknown` will fail, because `sys/alloc/mod.rs` will attempt to use `sys/alloc/wasm.rs`, the dlmalloc-based allocator used on `wasm32-unknown-unknown`. However, currently dlmalloc is only pulled in when `target_os = "unknown"`. Instead, we should make `Cargo.toml` and `alloc/mod.rs` match: either - disable `wasm.rs` in `alloc/mod.rs` where `not(target_os = "unknown")`, or - pull in `dlmalloc` for all Wasm targets with `target_family = "wasm32"` that aren't covered by the [upper branches of `alloc/mod.rs`](https://github.com/rust-lang/rust/blob/main/library/std/src/sys/alloc/mod.rs#L72-L100). This PR takes the latter approach, because it allows more code to compile without a custom allocator.
JonathanBrouwer
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Mar 23, 2026
`std`: include `dlmalloc` for all non-wasi Wasm targets Currently, building std for a custom Wasm target with an OS other than `unknown` will fail, because `sys/alloc/mod.rs` will attempt to use `sys/alloc/wasm.rs`, the dlmalloc-based allocator used on `wasm32-unknown-unknown`. However, currently dlmalloc is only pulled in when `target_os = "unknown"`. Instead, we should make `Cargo.toml` and `alloc/mod.rs` match: either - disable `wasm.rs` in `alloc/mod.rs` where `not(target_os = "unknown")`, or - pull in `dlmalloc` for all Wasm targets with `target_family = "wasm32"` that aren't covered by the [upper branches of `alloc/mod.rs`](https://github.com/rust-lang/rust/blob/main/library/std/src/sys/alloc/mod.rs#L72-L100). This PR takes the latter approach, because it allows more code to compile without a custom allocator.
JonathanBrouwer
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to JonathanBrouwer/rust
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Mar 23, 2026
`std`: include `dlmalloc` for all non-wasi Wasm targets Currently, building std for a custom Wasm target with an OS other than `unknown` will fail, because `sys/alloc/mod.rs` will attempt to use `sys/alloc/wasm.rs`, the dlmalloc-based allocator used on `wasm32-unknown-unknown`. However, currently dlmalloc is only pulled in when `target_os = "unknown"`. Instead, we should make `Cargo.toml` and `alloc/mod.rs` match: either - disable `wasm.rs` in `alloc/mod.rs` where `not(target_os = "unknown")`, or - pull in `dlmalloc` for all Wasm targets with `target_family = "wasm32"` that aren't covered by the [upper branches of `alloc/mod.rs`](https://github.com/rust-lang/rust/blob/main/library/std/src/sys/alloc/mod.rs#L72-L100). This PR takes the latter approach, because it allows more code to compile without a custom allocator.
This was referenced Mar 23, 2026
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…uwer Rollup of 13 pull requests Successful merges: - #154241 (`rust-analyzer` subtree update) - #153686 (`std`: include `dlmalloc` for all non-wasi Wasm targets) - #154105 (bootstrap: Pass `--features=rustc` to rustc_transmute) - #153069 ([BPF] add target feature allows-misaligned-mem-access) - #154085 (Parenthesize or-patterns in prefix pattern positions in pretty printer) - #154191 (refactor RangeFromIter overflow-checks impl) - #154207 (Refactor query loading) - #153540 (drop derive helpers during attribute parsing) - #154140 (Document consteval behavior of ub_checks, overflow_checks, is_val_statically_known.) - #154161 (On E0277 tweak help when single type impls traits) - #154218 (interpret/validity: remove unreachable error kind) - #154225 (diagnostics: avoid ICE in confusable_method_name for associated functions) - #154228 (Improve inline assembly error messages)
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…uwer Rollup of 13 pull requests Successful merges: - rust-lang/rust#154241 (`rust-analyzer` subtree update) - rust-lang/rust#153686 (`std`: include `dlmalloc` for all non-wasi Wasm targets) - rust-lang/rust#154105 (bootstrap: Pass `--features=rustc` to rustc_transmute) - rust-lang/rust#153069 ([BPF] add target feature allows-misaligned-mem-access) - rust-lang/rust#154085 (Parenthesize or-patterns in prefix pattern positions in pretty printer) - rust-lang/rust#154191 (refactor RangeFromIter overflow-checks impl) - rust-lang/rust#154207 (Refactor query loading) - rust-lang/rust#153540 (drop derive helpers during attribute parsing) - rust-lang/rust#154140 (Document consteval behavior of ub_checks, overflow_checks, is_val_statically_known.) - rust-lang/rust#154161 (On E0277 tweak help when single type impls traits) - rust-lang/rust#154218 (interpret/validity: remove unreachable error kind) - rust-lang/rust#154225 (diagnostics: avoid ICE in confusable_method_name for associated functions) - rust-lang/rust#154228 (Improve inline assembly error messages)
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…uwer Rollup of 13 pull requests Successful merges: - rust-lang/rust#154241 (`rust-analyzer` subtree update) - rust-lang/rust#153686 (`std`: include `dlmalloc` for all non-wasi Wasm targets) - rust-lang/rust#154105 (bootstrap: Pass `--features=rustc` to rustc_transmute) - rust-lang/rust#153069 ([BPF] add target feature allows-misaligned-mem-access) - rust-lang/rust#154085 (Parenthesize or-patterns in prefix pattern positions in pretty printer) - rust-lang/rust#154191 (refactor RangeFromIter overflow-checks impl) - rust-lang/rust#154207 (Refactor query loading) - rust-lang/rust#153540 (drop derive helpers during attribute parsing) - rust-lang/rust#154140 (Document consteval behavior of ub_checks, overflow_checks, is_val_statically_known.) - rust-lang/rust#154161 (On E0277 tweak help when single type impls traits) - rust-lang/rust#154218 (interpret/validity: remove unreachable error kind) - rust-lang/rust#154225 (diagnostics: avoid ICE in confusable_method_name for associated functions) - rust-lang/rust#154228 (Improve inline assembly error messages)
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Currently, building std for a custom Wasm target with an OS other than
unknownwill fail, becausesys/alloc/mod.rswill attempt to usesys/alloc/wasm.rs, the dlmalloc-based allocator used onwasm32-unknown-unknown. However, currently dlmalloc is only pulled in whentarget_os = "unknown".Instead, we should make
Cargo.tomlandalloc/mod.rsmatch: eitherwasm.rsinalloc/mod.rswherenot(target_os = "unknown"), ordlmallocfor all Wasm targets withtarget_family = "wasm32"that aren't covered by the upper branches ofalloc/mod.rs.This PR takes the latter approach, because it allows more code to compile without a custom allocator.