Rollup merge of #126967 - alexcrichton:wasm32-wasip2-tier-2, r=Mark-Simulacrum

Promote the `wasm32-wasip2` target to Tier 2

This commit promotes the `wasm32-wasip2` Rust target to tier 2 as proposed in rust-lang/compiler-team#760. There are two major changes in this PR:

1. The `dist-various-2` container, which already produces the other WASI targets, now has an extra target added for `wasm32-wasip2`.
2. A new `wasm-component-ld` binary is added to all host toolchains when LLD is enabled. This is the linker used for the `wasm32-wasip2` target.

This new linker is added for all host toolchains to ensure that all host toolchains can produce the `wasm32-wasip2` target. This is similar to how `rust-lld` was originally included for all host toolchains to be able to produce WebAssembly output when the targets were first added. The new linker is developed [here][wasm-component-ld] and is pulled in via a crates.io-based dependency to the tree here.

[wasm-component-ld]: https://github.com/bytecodealliance/wasm-component-ld
This commit is contained in:
Trevor Gross 2024-07-16 16:15:15 -05:00 committed by GitHub
commit 4e4fa7eb37
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9 changed files with 264 additions and 3 deletions

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@ -1682,6 +1682,7 @@ dependencies = [
"compiler_builtins",
"rustc-std-workspace-alloc",
"rustc-std-workspace-core",
"serde",
]
[[package]]
@ -1891,6 +1892,12 @@ dependencies = [
"syn 2.0.67",
]
[[package]]
name = "id-arena"
version = "2.2.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "25a2bc672d1148e28034f176e01fffebb08b35768468cc954630da77a1449005"
[[package]]
name = "ident_case"
version = "1.0.1"
@ -2120,6 +2127,12 @@ version = "1.0.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "db13adb97ab515a3691f56e4dbab09283d0b86cb45abd991d8634a9d6f501760"
[[package]]
name = "lexopt"
version = "0.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "baff4b617f7df3d896f97fe922b64817f6cd9a756bb81d40f8883f2f66dcb401"
[[package]]
name = "libc"
version = "0.2.155"
@ -2634,7 +2647,7 @@ dependencies = [
"indexmap",
"memchr",
"ruzstd 0.5.0",
"wasmparser",
"wasmparser 0.118.2",
]
[[package]]
@ -3445,7 +3458,7 @@ dependencies = [
"object 0.34.0",
"regex",
"similar",
"wasmparser",
"wasmparser 0.118.2",
]
[[package]]
@ -3832,7 +3845,7 @@ dependencies = [
"thin-vec",
"thorin-dwp",
"tracing",
"wasm-encoder",
"wasm-encoder 0.200.0",
"windows",
]
@ -5276,6 +5289,15 @@ dependencies = [
"color-eyre",
]
[[package]]
name = "spdx"
version = "0.10.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "47317bbaf63785b53861e1ae2d11b80d6b624211d42cb20efcd210ee6f8a14bc"
dependencies = [
"smallvec",
]
[[package]]
name = "spdx-expression"
version = "0.5.2"
@ -6324,6 +6346,28 @@ version = "0.2.92"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "af190c94f2773fdb3729c55b007a722abb5384da03bc0986df4c289bf5567e96"
[[package]]
name = "wasm-component-ld"
version = "0.5.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "314d932d5e84c9678751b85498b1482b2f32f185744e449d3ce0b1d400376dad"
dependencies = [
"anyhow",
"clap",
"lexopt",
"tempfile",
"wasmparser 0.210.0",
"wat",
"wit-component",
]
[[package]]
name = "wasm-component-ld-wrapper"
version = "0.1.0"
dependencies = [
"wasm-component-ld",
]
[[package]]
name = "wasm-encoder"
version = "0.200.0"
@ -6333,6 +6377,40 @@ dependencies = [
"leb128",
]
[[package]]
name = "wasm-encoder"
version = "0.210.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e7e3764d9d6edabd8c9e16195e177be0d20f6ab942ad18af52860f12f82bc59a"
dependencies = [
"leb128",
]
[[package]]
name = "wasm-encoder"
version = "0.211.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "5e7d931a1120ef357f32b74547646b6fa68ea25e377772b72874b131a9ed70d4"
dependencies = [
"leb128",
]
[[package]]
name = "wasm-metadata"
version = "0.210.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "012729d1294907fcb0866f08460ab95426a6d0b176a599619b84cac7653452b4"
dependencies = [
"anyhow",
"indexmap",
"serde",
"serde_derive",
"serde_json",
"spdx",
"wasm-encoder 0.210.0",
"wasmparser 0.210.0",
]
[[package]]
name = "wasmparser"
version = "0.118.2"
@ -6343,6 +6421,42 @@ dependencies = [
"semver",
]
[[package]]
name = "wasmparser"
version = "0.210.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "a7bbcd21e7581619d9f6ca00f8c4f08f1cacfe58bf63f83af57cd0476f1026f5"
dependencies = [
"ahash",
"bitflags 2.5.0",
"hashbrown",
"indexmap",
"semver",
"serde",
]
[[package]]
name = "wast"
version = "211.0.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b25506dd82d00da6b14a87436b3d52b1d264083fa79cdb72a0d1b04a8595ccaa"
dependencies = [
"bumpalo",
"leb128",
"memchr",
"unicode-width",
"wasm-encoder 0.211.1",
]
[[package]]
name = "wat"
version = "1.211.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "eb716ca6c86eecac2d82541ffc39860118fc0af9309c4f2670637bea2e1bdd7d"
dependencies = [
"wast",
]
[[package]]
name = "winapi"
version = "0.3.9"
@ -6570,6 +6684,43 @@ dependencies = [
"memchr",
]
[[package]]
name = "wit-component"
version = "0.210.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "a450bdb5d032acf1fa0865451fa0c6f50e62f2d31eaa8dba967c2e2d068694a4"
dependencies = [
"anyhow",
"bitflags 2.5.0",
"indexmap",
"log",
"serde",
"serde_derive",
"serde_json",
"wasm-encoder 0.210.0",
"wasm-metadata",
"wasmparser 0.210.0",
"wit-parser",
]
[[package]]
name = "wit-parser"
version = "0.210.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "60a965cbd439af19a4b44a54a97ab8957d86f02d01320efc9e31c1d3605c6710"
dependencies = [
"anyhow",
"id-arena",
"indexmap",
"log",
"semver",
"serde",
"serde_derive",
"serde_json",
"unicode-xid",
"wasmparser 0.210.0",
]
[[package]]
name = "writeable"
version = "0.5.5"

View File

@ -45,6 +45,7 @@ members = [
"src/tools/opt-dist",
"src/tools/coverage-dump",
"src/tools/rustc-perf-wrapper",
"src/tools/wasm-component-ld",
]
exclude = [
@ -104,6 +105,9 @@ rustc-demangle.debug = 0
[profile.release.package.lld-wrapper]
debug = 0
strip = true
[profile.release.package.wasm-component-ld-wrapper]
debug = 0
strip = true
[patch.crates-io]
# See comments in `library/rustc-std-workspace-core/README.md` for what's going on

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@ -1820,6 +1820,21 @@ impl Step for Assemble {
&self_contained_lld_dir.join(exe(name, target_compiler.host)),
);
}
// In addition to `rust-lld` also install `wasm-component-ld` when
// LLD is enabled. This is a relatively small binary that primarily
// delegates to the `rust-lld` binary for linking and then runs
// logic to create the final binary. This is used by the
// `wasm32-wasip2` target of Rust.
let wasm_component_ld_exe =
builder.ensure(crate::core::build_steps::tool::WasmComponentLd {
compiler: build_compiler,
target: target_compiler.host,
});
builder.copy_link(
&wasm_component_ld_exe,
&libdir_bin.join(wasm_component_ld_exe.file_name().unwrap()),
);
}
if builder.config.llvm_enabled(target_compiler.host) {

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@ -337,6 +337,7 @@ bootstrap_tool!(
RustdocGUITest, "src/tools/rustdoc-gui-test", "rustdoc-gui-test", is_unstable_tool = true, allow_features = "test";
CoverageDump, "src/tools/coverage-dump", "coverage-dump";
RustcPerfWrapper, "src/tools/rustc-perf-wrapper", "rustc-perf-wrapper";
WasmComponentLd, "src/tools/wasm-component-ld", "wasm-component-ld", is_unstable_tool = true, allow_features = "min_specialization";
);
#[derive(Debug, Clone, Hash, PartialEq, Eq)]

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@ -112,6 +112,7 @@ ENV TARGETS=$TARGETS,wasm32-unknown-unknown
ENV TARGETS=$TARGETS,wasm32-wasi
ENV TARGETS=$TARGETS,wasm32-wasip1
ENV TARGETS=$TARGETS,wasm32-wasip1-threads
ENV TARGETS=$TARGETS,wasm32-wasip2
ENV TARGETS=$TARGETS,sparcv9-sun-solaris
ENV TARGETS=$TARGETS,x86_64-pc-solaris
ENV TARGETS=$TARGETS,x86_64-unknown-linux-gnux32

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@ -95,7 +95,12 @@ const EXCEPTIONS: ExceptionList = &[
("self_cell", "Apache-2.0"), // rustc (fluent translations)
("snap", "BSD-3-Clause"), // rustc
("wasm-encoder", "Apache-2.0 WITH LLVM-exception"), // rustc
("wasm-metadata", "Apache-2.0 WITH LLVM-exception"), // rustc
("wasmparser", "Apache-2.0 WITH LLVM-exception"), // rustc
("wast", "Apache-2.0 WITH LLVM-exception"), // rustc
("wat", "Apache-2.0 WITH LLVM-exception"), // rustc
("wit-component", "Apache-2.0 WITH LLVM-exception"), // rustc
("wit-parser", "Apache-2.0 WITH LLVM-exception"), // rustc
// tidy-alphabetical-end
];

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@ -0,0 +1,13 @@
# See the `README.md` in this directory for what this tool is.
[package]
name = "wasm-component-ld-wrapper"
version = "0.1.0"
edition = "2021"
[[bin]]
name = "wasm-component-ld"
path = "src/main.rs"
[dependencies]
wasm-component-ld = "0.5.4"

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@ -0,0 +1,62 @@
# `wasm-component-ld`
This wrapper is a wrapper around the [`wasm-component-ld`] crates.io crate. That
crate. That crate is itself a thin wrapper around two pieces:
* `wasm-ld` - the LLVM-based linker distributed as part of LLD and packaged in
Rust as `rust-lld`.
* [`wit-component`] - a Rust crate for creating a [WebAssembly Component] from a
core wasm module.
This linker is used for Rust's `wasm32-wasip2` target to natively output a
component instead of a core WebAssembly module, unlike other WebAssembly
targets. If you're confused about any of this here's an FAQ-style explanation of
what's going on here:
* **What's a component?** - It's a proposal to the WebAssembly standard
primarily developed at this time by out-of-browser use cases of WebAssembly.
You can find high-level documentation [here][component docs].
* **What's WASIp2?** - Not to be confused with WASIp1, WASIp0,
`wasi_snapshot_preview1`, or `wasi_unstable`, it's a version of WASI. Released
in January 2024 it's the first version of WASI defined in terms of the
component model.
* **Why does this need its own linker?** - like any target that Rust has the
`wasm32-wasip2` target needs a linker. What makes this different from other
WebAssembly targets is that WASIp2 is defined at the component level, not core
WebAssembly level. This means that filesystem functions take a `string`
instead of `i32 i32`, for example. This means that the raw output of LLVM and
`wasm-ld`, a core WebAssembly module, is not suitable.
* **Isn't writing a linker really hard?** - Generally, yes, but this linker
works by first asking `wasm-ld` to do all the hard work. It invokes `wasm-ld`
and then uses the output core WebAssembly module to create a component.
* **How do you create a component from a core module?** - this is the purpose of
the [`wit-component`] crate, notably the `ComponentEncoder` type. This uses
component type information embedded in the core module and a general set of
conventions/guidelines with what the core module imports/exports. A component
is then hooked up to codify all of these conventions in a component itself.
* **Why not require users to run `wit-component` themselves?** - while possible
it adds friction to the usage `wasm32-wasip2` target. More importantly though
the "module only" output of the `wasm32-wasip2` target is not ready right now.
The standard library still imports from `wasi_snapshot_preview1` and it will
take time to migrate all usage to WASIp2.
* **What exactly does this linker do?** - the `wasm-component-ld` has the same
CLI interface and flags as `wasm-ld`, plus some more that are
component-specific. These flags are used to forward most flags to `wasm-ld` to
produce a core wasm module. After the core wasm module is produced the
`wit-component` crate will read custom sections in the final binary which
contain component type information. After merging all this type information
together a component is produced which wraps the core module.
If you've got any other questions about this linker or its operation don't
hesitate to reach out to the maintainers of the `wasm32-wasip2` target.
[`wasm-component-ld`]: https://crates.io/crates/wasm-component-ld
[`wit-component`]: https://crates.io/crates/wit-component
[WebAssembly Component]: https://github.com/webassembly/component-model
[component docs]: https://component-model.bytecodealliance.org/

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@ -0,0 +1,9 @@
// See the `README.md` in this directory for what this tool is.
// The source for this crate lives at
// https://github.com/bytecodealliance/wasm-component-ld and the binary is
// independently used in other projects such as `wasi-sdk` so the `main`
// function is just reexported here to delegate. A Cargo dependency is used to
// facilitate version management in the Rust repository and work well with
// vendored/offline builds.
use wasm_component_ld::main;