std: Get the standard library compiling for wasm64

[alexcrichton]

This commit goes through and updates various #[cfg] as appropriate to
get the wasm64-unknown-unknown target behaving similarly to the
wasm32-unknown-unknown target. Most of this is just updating various
conditions for target_arch = "wasm32" to also account for target_arch = "wasm64" where appropriate. This commit also lists wasm64 as an
allow-listed architecture to not have the restricted_std feature
enabled, enabling experimentation with -Z build-std externally.

The main goal of this commit is to enable playing around with
wasm64-unknown-unknown externally via -Z build-std in a way that's
similar to the wasm32-unknown-unknown target. These targets are
effectively the same and only differ in their pointer size, but wasm64
is much newer and has much less ecosystem/library support so it'll still
take time to get wasm64 fully-fledged.

[rust-highfive]

r? @yaahc

(rust-highfive has picked a reviewer for you, use r? to override)

[rust-highfive]

⚠️ Warning ⚠️

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

[alexcrichton]

As a heads up there are some sibling PRs which are not required to get pulled into libstd just yet but will likely want to get pulled in once they're merged:

• Adding a core::arch::wasm64 module - Add a rudimentary wasm64 module with intrinsics stdarch#1240
• Building intrinsics like memcpy and such for wasm64 in compiler-builtins - Adjust some build directives for wasm64 compiler-builtins#439

This PR, however, I believe is still standalone and can be landed separately from those.

It's also worth pointing out that I believe there's an open design question about whether the compiler should provide a built-in #[cfg] of the form #[cfg(wasm)] or something like that to avoid any(target_arch = "wasm32", target_arch = "wasm64") but I don't really want to poke that hornets nest so I opted for the currently-working-but-more-verbose route of adding target_arch = "wasm64" in various places. I've updated to use target_family = "wasm" which already exists (yay!)

[devsnek]

i think you should update platform-support.md to move wasm64 from * to ? for std.

[joshtriplett]

This isn't something you need to fix in this PR, but it feels like these should use #[cfg(target_pointer_width = "64")] and similar, and then just list any exceptions to that.

[bjorn3]

If someone forgets to add an exception that may lead to a hard to track down bug.

[joshtriplett]

I think this would still be a maintenance improvement even if code directly above this had a list of all target architectures and a compilation error for an unknown architecture.

[joshtriplett]

Please consider adding some minimal target documentation for wasm64-unknown-unknown, such as to document the default features it expects in the runtime.

[alexcrichton]

I'm not sure what you want added here? I mentioned above that I don't think it makes sense to document features and I would rather remove the features than try to document them, but otherwise I don't know how much to document this or what should be included here.

[alexcrichton]

Ok I pushed up a few more commits (the latest two). One works around a crash in LLVM that's wasm64-specific and has an open LLVM bug for it, and the other is some results from running the test suite for wasm64. I've opted to not actually include any compiletest or src/test/ui/* changes just yet since the test suite isn't fully passing, and I don't think it's necessarily useful to have an intermediate state for now.

In any case this should be good to go! (this was otherwise just a few other things I noticed today)

[alexcrichton]

With the latest commit that updates stdarch/compiler-builtins then this PR alone should be enough to make wasm64 a pretty usable target with -Zbuild-std. There are still a number of LLVM bugs to handle such as

• https://bugs.llvm.org/show_bug.cgi?id=52352 - general crash in some code
• https://bugs.llvm.org/show_bug.cgi?id=52376 - crash for -generate-arange-section
• https://bugs.llvm.org/show_bug.cgi?id=52350 - crash for simd-using code

That's sort of inevitable for a new target, though, and will require backports and/or custom-built rustc with tip-of-tree LLVM to work around.

[devsnek]

[bors]

☔ The latest upstream changes (presumably #90392) made this pull request unmergeable. Please resolve the merge conflicts.

[alexcrichton]

Rebased!

[alexcrichton]

ping @yaahc would you be able to take a look at this? If not no worries and I can try to find someone else

[alexcrichton]

I reached out to @joshtriplett and he said he'd be willing to take over review, so I'm going to...

r? @joshtriplett

[alexcrichton]

I didn't realize this documentation existed before, and I think it's great to have! I also don't mean to usurp a role of sole maintainer here, if others would like to be added I'd be happy to add as part of this PR

[ehuss]

@bors retry

x86_64-gnu-distcheck hung on Updating crates.io index

[bors]

⌛ Testing commit af217f7 with merge b192c9da9d53ad26eca875234bfd6140c98ed5e1...

[bors]

💔 Test failed - checks-actions

[rust-log-analyzer]

The job x86_64-msvc-cargo failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

test workspaces::ws_warn_unused ... ok

failures:

---- lto::complicated stdout ----
running `D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\release\cargo.exe build -v --release`
thread 'lto::complicated' panicked at '
test failed running `D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\release\cargo.exe build -v --release`
error: process exited with code 101 (expected 0)

--- stderr
--- stderr
    Updating `dummy-registry` index
---
The targets should have unique names.
Consider changing their names to be unique or compiling them separately.
This may become a hard error in the future; see <https://github.com/rust-lang/cargo/issues/6313>.
   Compiling dep-shared v0.0.1
   Compiling dep-build2 v0.0.1
   Compiling dep-proc-macro2 v0.0.1
   Compiling dep-normal2 v0.0.1
     Running `rustc --crate-name dep_shared D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\home\.cargo\registry\src\-5df8a1ccca24ba7a\dep-shared-0.0.1\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C metadata=815663fa4ca118de -C extra-filename=-815663fa4ca118de --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --cap-lints allow`
     Running `rustc --crate-name dep_proc_macro2 D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\home\.cargo\registry\src\-5df8a1ccca24ba7a\dep-proc-macro2-0.0.1\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C embed-bitcode=no -C metadata=f829152b9eb79c53 -C extra-filename=-f829152b9eb79c53 --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --cap-lints allow`
     Running `rustc --crate-name dep_normal2 D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\home\.cargo\registry\src\-5df8a1ccca24ba7a\dep-normal2-0.0.1\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C linker-plugin-lto -C metadata=8cf56e81cc7e8007 -C extra-filename=-8cf56e81cc7e8007 --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --cap-lints allow`
     Running `rustc --crate-name dep_build2 D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\home\.cargo\registry\src\-5df8a1ccca24ba7a\dep-build2-0.0.1\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C embed-bitcode=no -C metadata=df572682f4638748 -C extra-filename=-df572682f4638748 --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --cap-lints allow`
   Compiling dep-normal v0.0.1
   Compiling dep-build v0.0.1
     Running `rustc --crate-name dep_normal D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\home\.cargo\registry\src\-5df8a1ccca24ba7a\dep-normal-0.0.1\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C linker-plugin-lto -C metadata=06ea447f8e785b1a -C extra-filename=-06ea447f8e785b1a --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --extern dep_normal2=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_normal2-8cf56e81cc7e8007.rmeta --extern dep_shared=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_shared-815663fa4ca118de.rmeta --cap-lints allow`
     Running `rustc --crate-name dep_build D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\home\.cargo\registry\src\-5df8a1ccca24ba7a\dep-build-0.0.1\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C embed-bitcode=no -C metadata=4b7343fd1f9e1e57 -C extra-filename=-4b7343fd1f9e1e57 --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --extern dep_build2=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_build2-df572682f4638748.rmeta --extern dep_shared=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_shared-815663fa4ca118de.rmeta --cap-lints allow`
   Compiling dep-proc-macro v0.0.1
     Running `rustc --crate-name dep_proc_macro D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\home\.cargo\registry\src\-5df8a1ccca24ba7a\dep-proc-macro-0.0.1\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type proc-macro --emit=dep-info,link -C prefer-dynamic -C opt-level=3 -C embed-bitcode=no -C metadata=92b443923583e648 -C extra-filename=-92b443923583e648 --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --extern dep_proc_macro2=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_proc_macro2-f829152b9eb79c53.rlib --extern dep_shared=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_shared-815663fa4ca118de.rlib --extern proc_macro --cap-lints allow`
   Compiling test v0.0.0 (D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo)
     Running `rustc --crate-name build_script_build build.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type bin --emit=dep-info,link -C opt-level=3 -C embed-bitcode=no -C metadata=1132ccd72abf6ae6 -C extra-filename=-1132ccd72abf6ae6 --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\build\test-1132ccd72abf6ae6 -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --extern dep_build=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_build-4b7343fd1f9e1e57.rlib`
     Running `D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\build\test-1132ccd72abf6ae6\build-script-build`
     Running `rustc --crate-name test src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type cdylib --crate-type staticlib --emit=dep-info,link -C opt-level=3 -C lto -C metadata=10d13534f609fec7 --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --extern dep_normal=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_normal-06ea447f8e785b1a.rlib --extern dep_proc_macro=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\dep_proc_macro-92b443923583e648.dll`
     Running `rustc --crate-name test src\main.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type bin --emit=dep-info,link -C opt-level=3 -C lto -C metadata=f9bd7972e02c2e3b --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --extern dep_normal=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_normal-06ea447f8e785b1a.rlib --extern dep_proc_macro=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\dep_proc_macro-92b443923583e648.dll`
error: linking with `link.exe` failed: exit code: 1201
  |
  = note: "C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Enterprise\\VC\\Tools\\MSVC\\14.29.30133\\bin\\HostX64\\x64\\link.exe" "/DEF:C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\rustcqQHjxm\\lib.def" "/NOLOGO" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-msvc\\stage2-tools\\x86_64-pc-windows-msvc\\tmp\\cit\\t1298\\foo\\target\\release\\deps\\test.test.3b04ecf7-cgu.0.rcgu.o" "/LIBPATH:D:\\a\\rust\\rust\\build\\x86_64-pc-windows-msvc\\stage2-tools\\x86_64-pc-windows-msvc\\tmp\\cit\\t1298\\foo\\target\\release\\deps" "/LIBPATH:D:\\a\\rust\\rust\\build\\x86_64-pc-windows-msvc\\stage2\\lib\\rustlib\\x86_64-pc-windows-msvc\\lib" "D:\\a\\rust\\rust\\build\\x86_64-pc-windows-msvc\\stage2\\lib\\rustlib\\x86_64-pc-windows-msvc\\lib\\libcompiler_builtins-2e46b64d42824fd5.rlib" "kernel32.lib" "ws2_32.lib" "bcrypt.lib" "advapi32.lib" "userenv.lib" "kernel32.lib" "msvcrt.lib" "/NXCOMPAT" "/LIBPATH:D:\\a\\rust\\rust\\build\\x86_64-pc-windows-msvc\\stage2\\lib\\rustlib\\x86_64-pc-windows-msvc\\lib" "/OUT:D:\\a\\rust\\rust\\build\\x86_64-pc-windows-msvc\\stage2-tools\\x86_64-pc-windows-msvc\\tmp\\cit\\t1298\\foo\\target\\release\\deps\\test.dll" "/OPT:REF,ICF" "/DLL" "/IMPLIB:D:\\a\\rust\\rust\\build\\x86_64-pc-windows-msvc\\stage2-tools\\x86_64-pc-windows-msvc\\tmp\\cit\\t1298\\foo\\target\\release\\deps\\test.dll.lib" "/DEBUG"
  = note: LINK : fatal error LNK1201: error writing to program database 'D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\test.pdb'; check for insufficient disk space, invalid path, or insufficient privilege

error: could not compile `test` due to previous error

Caused by:
Caused by:
  process didn't exit successfully: `rustc --crate-name test src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type cdylib --crate-type staticlib --emit=dep-info,link -C opt-level=3 -C lto -C metadata=10d13534f609fec7 --out-dir D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps -L dependency=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps --extern dep_normal=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\libdep_normal-06ea447f8e785b1a.rlib --extern dep_proc_macro=D:\a\rust\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\tmp\cit\t1298\foo\target\release\deps\dep_proc_macro-92b443923583e648.dll` (exit code: 1)
error: build failed
', src\tools\cargo\tests\testsuite\lto.rs:217:10
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[ehuss]

@bors retry

LNK1201 #81890

[bors]

⌛ Testing commit af217f7 with merge b6f580a...

[bors]

☀️ Test successful - checks-actions
Approved by: joshtriplett
Pushing b6f580a to master...

[rust-timer]

Finished benchmarking commit (b6f580a): comparison url.

Summary: This change led to large relevant mixed results 🤷 in compiler performance.

• Large improvement in instruction counts (up to -4.3% on incr-unchanged builds of clap-rs)
• Moderate regression in instruction counts (up to 1.0% on incr-unchanged builds of issue-88862)

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression

[pnkfelix]

Visiting for performance triage.

There were a lot of various changes in this PR, such as updates to dependencies (compiler_builtins and dlmalloc). We probably shoud have done a pre-merge rust-timer run on this PR.

The flagged regressions of magnitude greater than 0.5% are isolated to "issue-88862 check" and "style-servo check". The improvements tended to outweigh the regressions. For the most part almost all significant performance effects are isolated to check builds.

@rustbot label +perf-regression-triaged