Add unwinder_private_data_size for wasm64 target by richArved · Pull Request #156573 · rust-lang/rust

richArved · 2026-05-14T13:36:24Z

Fixes missing unwinder_private_data_size for the wasm64 architecture

rustbot · 2026-05-14T13:36:30Z

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daxpedda

Cc @hoodmane you might be interested in that sort of issue.

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daxpedda · 2026-05-14T13:42:32Z

 #[cfg(all(target_arch = "wasm32", target_os = "emscripten"))]
 pub const unwinder_private_data_size: usize = 20;


Suggested change

#[cfg(all(target_arch = "wasm32", target_os = "emscripten"))]

pub const unwinder_private_data_size: usize = 20;

#[cfg(all(target_family = "wasm", target_os = "emscripten"))]

pub const unwinder_private_data_size: usize = 20;

done, thanks !

daxpedda

AFAICS a Wasm64 Emscripten target doesn't exist. So I'm not sure what this is supposed to fix.

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richArved · 2026-05-14T18:01:35Z

AFAICS a Wasm64 Emscripten target doesn't exist. So I'm not sure what this is supposed to fix.

View changes since this review

It isn't a fix for a built-in tier target. It's for custom target specs. Changing it to target_family = "wasm" would fix the compiler error of the unwind crate because the cfg gate target_arch = "wasm32" doesn't match and the constant is missing, without affecting the existing wasm32 behavior. Also it future-proofs against any official wasm64 targets that may be added later.

richArved · 2026-05-19T12:43:42Z

any news on this?

richArved · 2026-05-24T16:37:21Z

Hey @Mark-Simulacrum, Are there any news to this? If you need any further explanation let me know. Thanks

gergelyvagujhelyi · 2026-06-04T13:50:39Z

Please either merge this or my solution #156912
I need this so I can fit an llm into memory.

Mark-Simulacrum · 2026-06-07T02:41:00Z

@bors r+

I'll go ahead and approve this since it's for a below-tier-3 target, but it would be good to document where this value comes from (both for wasm32 and 64).

rust-bors · 2026-06-07T02:41:03Z

📌 Commit 09f39f3 has been approved by Mark-Simulacrum

It is now in the queue for this repository.

Mark-Simulacrum · 2026-06-07T02:41:25Z

@bors squash msg="Add unwinder_private_data_size for wasm64 target"

rust-bors · 2026-06-07T02:41:46Z

🔨 2 commits were squashed into aa5b5a2.

This pull request was unapproved.

Mark-Simulacrum · 2026-06-07T02:42:08Z

@bors r+ rollup

rust-bors · 2026-06-07T02:42:10Z

📌 Commit aa5b5a2 has been approved by Mark-Simulacrum

It is now in the queue for this repository.

Add unwinder_private_data_size for wasm64 target Fixes missing unwinder_private_data_size for the wasm64 architecture

Rollup of 25 pull requests Successful merges: - #157251 (`rust-analyzer` subtree update) - #157533 (Subtree sync for rustc_codegen_cranelift) - #154742 (Add APIs for case folding to the standard library) - #155144 (mir_build: Add an extra intermediate step in MIR building for patterns ) - #156222 (Stabilize `Result::map_or_default` and `Option::map_or_default`) - #157016 (add `extern "tail"` calling convention) - #157264 (diagnostics: Fix ICE building a trait ref in method suggestions) - #157386 (Parse deprecated note links separately in rustc_resolve) - #157483 (fix windows-gnu TLS leak) - #157488 (compiletest: inject `#![windows_subsystem = "windows"]` to debuginfo tests on Windows) - #157509 (remove solaris implementation for File::lock, it has the wrong semantics) - #157521 (Rename `SyncView::{as_pin => as_pin_ref}`) - #156136 (Move tests box) - #156573 (Add unwinder_private_data_size for wasm64 target) - #156783 (docs: make `Rc::into_raw` clickable in `Rc::increment_strong_count` doc) - #156840 (Stabilize `PathBuf::into_string`) - #156936 (Remove FIXME about impl PinCoerceUnsized for UnsafePinned<T>) - #157365 (Revert "LLVM 23: Run AssignGUIDPass in some places") - #157380 (clarify compiler_fence (and fence) docs) - #157471 (Debug assert that parsed attributes are in the `BUILTIN_ATTRIBUTE_MAP`) - #157485 (Rename `errors.rs` file to `diagnostics.rs` (1/N)) - #157494 (Convert `QueryRegionConstraint` into a struct) - #157526 (std tests: skip a slow test on Miri) - #157531 (ci: bump x86_64-gnu base image to 26.04) - #157556 (Add `BTree::append()` change to 1.96.0 relnotes) Failed merges: - #155527 (Replace printables table with `unicode_data.rs` tables)

Rollup merge of #156573 - richArved:patch-1, r=Mark-Simulacrum Add unwinder_private_data_size for wasm64 target Fixes missing unwinder_private_data_size for the wasm64 architecture

Rollup of 25 pull requests Successful merges: - rust-lang/rust#157251 (`rust-analyzer` subtree update) - rust-lang/rust#157533 (Subtree sync for rustc_codegen_cranelift) - rust-lang/rust#154742 (Add APIs for case folding to the standard library) - rust-lang/rust#155144 (mir_build: Add an extra intermediate step in MIR building for patterns ) - rust-lang/rust#156222 (Stabilize `Result::map_or_default` and `Option::map_or_default`) - rust-lang/rust#157016 (add `extern "tail"` calling convention) - rust-lang/rust#157264 (diagnostics: Fix ICE building a trait ref in method suggestions) - rust-lang/rust#157386 (Parse deprecated note links separately in rustc_resolve) - rust-lang/rust#157483 (fix windows-gnu TLS leak) - rust-lang/rust#157488 (compiletest: inject `#![windows_subsystem = "windows"]` to debuginfo tests on Windows) - rust-lang/rust#157509 (remove solaris implementation for File::lock, it has the wrong semantics) - rust-lang/rust#157521 (Rename `SyncView::{as_pin => as_pin_ref}`) - rust-lang/rust#156136 (Move tests box) - rust-lang/rust#156573 (Add unwinder_private_data_size for wasm64 target) - rust-lang/rust#156783 (docs: make `Rc::into_raw` clickable in `Rc::increment_strong_count` doc) - rust-lang/rust#156840 (Stabilize `PathBuf::into_string`) - rust-lang/rust#156936 (Remove FIXME about impl PinCoerceUnsized for UnsafePinned<T>) - rust-lang/rust#157365 (Revert "LLVM 23: Run AssignGUIDPass in some places") - rust-lang/rust#157380 (clarify compiler_fence (and fence) docs) - rust-lang/rust#157471 (Debug assert that parsed attributes are in the `BUILTIN_ATTRIBUTE_MAP`) - rust-lang/rust#157485 (Rename `errors.rs` file to `diagnostics.rs` (1/N)) - rust-lang/rust#157494 (Convert `QueryRegionConstraint` into a struct) - rust-lang/rust#157526 (std tests: skip a slow test on Miri) - rust-lang/rust#157531 (ci: bump x86_64-gnu base image to 26.04) - rust-lang/rust#157556 (Add `BTree::append()` change to 1.96.0 relnotes) Failed merges: - rust-lang/rust#155527 (Replace printables table with `unicode_data.rs` tables)

Adds a wasm64-unknown-emscripten build variant alongside wasm32, lifting the 4 GiB linear-memory ceiling to 16 GiB so models whose working set exceeds 4 GiB can load. Unblocked by rust-lang/rust#156573 (wasm64 unwinder, merged 2026-06-07), so -Zbuild-std compiles std for the tier-3 target on a recent nightly with no rustlib patch. - js/targets/wasm64-unknown-emscripten.json: custom target spec (derived from the built-in wasm32 spec; 64-bit pointer width, panic=abort) - js/build.rs: arch-aware link flags (-sMEMORY64=1, 16 GiB ceiling on wasm64) - js/scripts/build-pkg-emscripten-wasm64.sh: build-std + JSON target pipeline - .cargo/config.toml: wasm64 target rustflags fallback - js/tests/test_emscripten_wasm64.mjs: smoke test - js_ci.yml: wasm64 build + test legs - README/llm.rs: document the 16 GiB ceiling + #156573 TEMPORARY: the workspace [patch] points llama-cpp-rs and wasm-bindgen at local clones of their wasm64-emscripten branches (build.rs -sMEMORY64; wasm-bindgen memory64 fixes for the emscripten path). Push those branches + re-pin to drop the [patch].

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 14, 2026

rustbot assigned Mark-Simulacrum May 14, 2026

daxpedda suggested changes May 14, 2026

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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-review Status: Awaiting review from the assignee but also interested parties. labels Jun 7, 2026

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Add unwinder_private_data_size for wasm64 target

aa5b5a2

rust-bors Bot added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Jun 7, 2026

rust-bors Bot removed the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Jun 7, 2026

rust-bors Bot force-pushed the patch-1 branch from 09f39f3 to aa5b5a2 Compare June 7, 2026 02:41

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 Jun 7, 2026

jhpratt added a commit to jhpratt/rust that referenced this pull request Jun 7, 2026

Rollup merge of rust-lang#156573 - richArved:patch-1, r=Mark-Simulacrum

d1ea050

Add unwinder_private_data_size for wasm64 target Fixes missing unwinder_private_data_size for the wasm64 architecture

jhpratt mentioned this pull request Jun 7, 2026

Rollup of 21 pull requests #157554

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jhpratt added a commit to jhpratt/rust that referenced this pull request Jun 7, 2026

Rollup merge of rust-lang#156573 - richArved:patch-1, r=Mark-Simulacrum

e1c583a

Add unwinder_private_data_size for wasm64 target Fixes missing unwinder_private_data_size for the wasm64 architecture

This was referenced Jun 7, 2026

Rollup of 22 pull requests #157555

Closed

Rollup of 25 pull requests #157558

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rust-bors Bot merged commit 7eeb5b9 into rust-lang:main Jun 7, 2026
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rustbot added this to the 1.98.0 milestone Jun 7, 2026

rust-timer added a commit that referenced this pull request Jun 7, 2026

Unrolled build for #156573

7d78aa2

Rollup merge of #156573 - richArved:patch-1, r=Mark-Simulacrum Add unwinder_private_data_size for wasm64 target Fixes missing unwinder_private_data_size for the wasm64 architecture

		#[cfg(all(target_arch = "wasm32", target_os = "emscripten"))]
		pub const unwinder_private_data_size: usize = 20;

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