Introduce perma-unstable `wasm-c-abi` flag #117919

daxpedda · 2023-11-14T22:15:38Z

Now that wasm-bindgen v0.2.88 supports the spec-compliant C ABI, the idea is to switch to that in a future version of Rust. In the meantime it would be good to let people test and play around with it.

This PR introduces a new perma-unstable -Zwasm-c-abi compiler flag, which switches to the new spec-compliant C ABI when targeting wasm32-unknown-unknown.

Alternatively, we could also stabilize this and then deprecate it when we switch. I will leave this to the Rust maintainers to decide.

This is a companion PR to #117918, but they could be merged independently.
MCP: rust-lang/compiler-team#703
Tracking issue: #122532

rustbot · 2023-11-14T22:15:46Z

r? @compiler-errors

(rustbot has picked a reviewer for you, use r? to override)

rustbot · 2023-11-14T22:15:48Z

These commits modify compiler targets.
(See the Target Tier Policy.)

daxpedda · 2023-11-14T22:17:47Z

compiler/rustc_target/src/spec/mod.rs

+pub trait HasWasmCAbiOpt {
+    fn wasm_c_abi_opt(&self) -> bool;
+}


This is the best I could come up with to keep the logic inside of Target::adjust_abi(), I believe moving this logic outside of it would introduce some very hacky code that could potentially become a trap for other contributors.

I'm pretty unfamiliar with the compiler though, so any advice would be appreciated.

rustbot · 2023-11-14T22:36:01Z

Some changes occurred in compiler/rustc_codegen_gcc

cc @antoyo

compiler/rustc_session/src/options.rs

rustbot · 2023-11-16T08:36:15Z

Some changes occurred in src/tools/cargo

cc @ehuss

daxpedda · 2023-11-16T08:39:22Z

Apologies @ehuss, I messed up during rebasing onto master and mistakenly changed the Cargo submodule!

bors · 2023-12-01T00:56:35Z

☔ The latest upstream changes (presumably #116892) made this pull request unmergeable. Please resolve the merge conflicts.

compiler-errors · 2023-12-05T16:03:33Z

Sorry, I'm extremely busy

r? compiler

petrochenkov · 2023-12-05T16:32:21Z

r? compiler
I'm overloaded with reviews.

b-naber · 2023-12-11T21:31:27Z

The companion PR is lang-nominated, if the lang team approves that change this one could be merged too, but if this PR would be merged independently it would need at least an MCP, I think, since it introduces a new flag.

Introduce perma-unstable `wasm-c-abi` flag Now that `wasm-bindgen` v0.2.88 supports the spec-compliant C ABI, the idea is to switch to that in a future version of Rust. In the meantime it would be good to let people test and play around with it. This PR introduces a new perma-unstable `-Zwasm-c-abi` compiler flag, which switches to the new spec-compliant C ABI when targeting `wasm32-unknown-unknown`. Alternatively, we could also stabilize this and then deprecate it when we switch. I will leave this to the Rust maintainers to decide. This is a companion PR to rust-lang#117918, but they could be merged independently. MCP: rust-lang/compiler-team#703 Tracking issue: rust-lang#122532

…kingjubilee Rollup of 6 pull requests Successful merges: - rust-lang#117919 (Introduce perma-unstable `wasm-c-abi` flag) - rust-lang#123571 (Correctly change type when adding adjustments on top of `NeverToAny`) - rust-lang#123752 (Properly handle emojis as literal prefix in macros) - rust-lang#123980 ( Add an opt-in to store incoming edges in `VecGraph` + misc) - rust-lang#124110 (Fix negating `f16` and `f128` constants) - rust-lang#124116 (when suggesting RUST_BACKTRACE=1, add a special note for Miri's env var isolation) r? `@ghost` `@rustbot` modify labels: rollup

Introduce perma-unstable `wasm-c-abi` flag Now that `wasm-bindgen` v0.2.88 supports the spec-compliant C ABI, the idea is to switch to that in a future version of Rust. In the meantime it would be good to let people test and play around with it. This PR introduces a new perma-unstable `-Zwasm-c-abi` compiler flag, which switches to the new spec-compliant C ABI when targeting `wasm32-unknown-unknown`. Alternatively, we could also stabilize this and then deprecate it when we switch. I will leave this to the Rust maintainers to decide. This is a companion PR to rust-lang#117918, but they could be merged independently. MCP: rust-lang/compiler-team#703 Tracking issue: rust-lang#122532

…kingjubilee Rollup of 9 pull requests Successful merges: - rust-lang#117919 (Introduce perma-unstable `wasm-c-abi` flag) - rust-lang#123406 (Force exhaustion in iter::ArrayChunks::into_remainder) - rust-lang#123752 (Properly handle emojis as literal prefix in macros) - rust-lang#123935 (Don't inline integer literals when they overflow - new attempt) - rust-lang#123980 ( Add an opt-in to store incoming edges in `VecGraph` + misc) - rust-lang#124019 (Use raw-dylib for Windows synchronization functions) - rust-lang#124110 (Fix negating `f16` and `f128` constants) - rust-lang#124112 (Fix ICE when there is a non-Unicode entry in the incremental crate directory) - rust-lang#124116 (when suggesting RUST_BACKTRACE=1, add a special note for Miri's env var isolation) r? `@ghost` `@rustbot` modify labels: rollup

bors · 2024-04-19T03:35:15Z

⌛ Testing commit 9e2c658 with merge 13e63f7...

bors · 2024-04-19T05:37:05Z

☀️ Test successful - checks-actions
Approved by: wesleywiser
Pushing 13e63f7 to master...

rust-timer · 2024-04-19T07:22:37Z

Finished benchmarking commit (13e63f7): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

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

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.0%	[2.0%, 2.0%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	3.1%	[2.1%, 4.4%]	8
Regressions ❌ (secondary)	2.7%	[2.1%, 3.5%]	11
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.1%	[2.1%, 4.4%]	8

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 673.311s -> 673.499s (0.03%)
Artifact size: 315.21 MiB -> 315.24 MiB (0.01%)

Introduce perma-unstable `wasm-c-abi` flag Now that `wasm-bindgen` v0.2.88 supports the spec-compliant C ABI, the idea is to switch to that in a future version of Rust. In the meantime it would be good to let people test and play around with it. This PR introduces a new perma-unstable `-Zwasm-c-abi` compiler flag, which switches to the new spec-compliant C ABI when targeting `wasm32-unknown-unknown`. Alternatively, we could also stabilize this and then deprecate it when we switch. I will leave this to the Rust maintainers to decide. This is a companion PR to rust-lang#117918, but they could be merged independently. MCP: rust-lang/compiler-team#703 Tracking issue: rust-lang#122532

Manishearth · 2024-08-28T21:57:59Z

Should this have been a -Cwasm-c-abi flag? I was under the impression -Z was for debugging and -C was for codegen

teohhanhui · 2024-08-29T04:21:24Z

@Manishearth https://doc.rust-lang.org/rustc/command-line-arguments.html#-z-set-unstable-options

Manishearth · 2024-08-29T04:45:53Z

ah, I see!

This... finally breaks down and requires rust nightly. I've been going to considerable lengths to try to avoid this, but... I earnestly don't think shipping C+Rust to wasm is possible without it. The main new thing here is the "-Zwasm-c-abi=spec" flag. As described in the README diff, it's essential for rust to call into C correctly when both are wasm'd. (It's beyond me why any other mode exists, but I'll... attempt to bite my tongue.) This critical flag was introduced in rust-lang/rust#117919 . Which describes it as "perma-unstable". And gosh I hope that's not actually going to be true... because again, this seems to be flat out *required* for Rust and C to play together in wasm. And also because "perma-unstable" is just a deeply silly concept, period, context-free. I do not understand any possible reason to want to push people *permanently* towards using "unstable" "nightly" compilers. I don't understand how this needs to be said, but creating a situation where the words "permanently unstable" go together is a Bad Idea. Anyway. The "target-feature=+bulk-memory" flag also comes along because without that, we get a "Uncaught RangeError: Maximum call stack size exceeded" error at runtime. It's attributed to "core::intrinsics::copy::precondition_check" called from "memmove". (That doesn't make a ton of sense to me, looking at the code, but... a lot of things don't make sense to me, looking at any of this; add it to the pile.) Whatever the reason, this flag makes it go. And now it's alive. It's taken days. But hello world has landed. Hooray.

rustbot assigned compiler-errors Nov 14, 2023

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Nov 14, 2023

daxpedda commented Nov 14, 2023

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Noratrieb reviewed Nov 16, 2023

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rustbot assigned petrochenkov and unassigned compiler-errors Dec 5, 2023

rustbot assigned b-naber and unassigned petrochenkov Dec 5, 2023

GuillaumeGomez mentioned this pull request Apr 18, 2024

Rollup of 7 pull requests #124133

Closed

workingjubilee mentioned this pull request Apr 18, 2024

Rollup of 6 pull requests #124140

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workingjubilee mentioned this pull request Apr 18, 2024

Rollup of 9 pull requests #124142

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bors added the merged-by-bors This PR was explicitly merged by bors. label Apr 19, 2024

bors merged commit 13e63f7 into rust-lang:master Apr 19, 2024

rustbot added this to the 1.79.0 milestone Apr 19, 2024

bors mentioned this pull request Apr 19, 2024

sanitizers: Stabilize AddressSanitizer and LeakSanitizer for the Tier 1 targets #123617

Open

daxpedda mentioned this pull request May 20, 2024

Implemented compatibility mode with wasm32-wasi rustwasm/wasm-bindgen#3324

Open

rafaelbeckel mentioned this pull request May 25, 2024

Align with the "C" ABI rustwasm/wasm-bindgen#3454

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5 tasks

rafaelbeckel mentioned this pull request Jun 10, 2024

Document wasm-bindgen incompatibility with C/C++ rustwasm/wasm-bindgen#2209

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Andrewp2 mentioned this pull request Jun 25, 2024

Add support for wasm32-unknown-unknown mlua-rs/mlua#23

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nikic mentioned this pull request Jul 10, 2024

Update to LLVM 19 #127513

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FreddyFunk mentioned this pull request Aug 21, 2024

Does it make sense to support WASM? rust-lang/libc#858

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workingjubilee mentioned this pull request Aug 23, 2024

Wasm ABI special cases scalar pairs (against tool conventions) and is not documented #129486

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Manishearth mentioned this pull request Aug 27, 2024

Rust Wasm ABI is unstable and will be changed eventually rust-diplomat/diplomat#661

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workingjubilee mentioned this pull request Oct 21, 2024

Add support for wasm exception handling to Emscripten target #131830

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simoncozens mentioned this pull request Dec 19, 2024

Revisiting wasm32-unknown-unknown rust-skia/rust-skia#1078

Open

Introduce perma-unstable wasm-c-abi flag #117919

Introduce perma-unstable wasm-c-abi flag #117919

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rust-timer commented Apr 19, 2024

Overall result: ❌ regressions - no action needed

Instruction count

Max RSS (memory usage)

Cycles

Binary size

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Manishearth commented Aug 28, 2024

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Introduce perma-unstable `wasm-c-abi` flag #117919

Introduce perma-unstable `wasm-c-abi` flag #117919

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