Cross-build browser WASM performance host tools - #133143
Merged
Merged
Conversation
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
|
Azure Pipelines: Successfully started running 6 pipeline(s). 10 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run. |
Contributor
There was a problem hiding this comment.
🔵 Needs a closer look
This changes cross-build behavior in the build graph and performance pipeline; it needs end-to-end CI validation to confirm it packages and runs correctly across the intended Linux environments.
Pull request overview
Adds an opt-in MSBuild property to control whether the CoreCLR host cross-components child build is invoked with CrossBuild=true, and enables that opt-in for the browser WASM performance build job to allow cross-building the host toolset in that scenario.
Changes:
- Introduced
CrossBuildHostTools(defaulting tofalse) to gate cross-building of the host cross-components build. - Switched the CoreCLR cross-tools
runtime.projchild invocation fromCrossBuild=falsetoCrossBuild=$(CrossBuildHostTools). - Enabled
/p:CrossBuildHostTools=truefor thebrowser_wasmCoreCLR perf build job.
File summaries
| File | Description |
|---|---|
| eng/Subsets.props | Adds CrossBuildHostTools and uses it to control CrossBuild for the CoreCLR host cross-components child build. |
| eng/pipelines/performance/templates/perf-wasm-build-jobs.yml | Enables CrossBuildHostTools for the browser WASM CoreCLR perf build. |
Review details
- Files reviewed: 2/2 changed files
- Comments generated: 0
- Review effort level: Lite
Member
Author
|
performance pr is dotnet/performance#5297 pipeline failure is https://dev.azure.com/dnceng-public/public/_build/results?buildId=1579905&view=results |
This was referenced Sep 3, 2026
Open
maraf
approved these changes
Sep 3, 2026
Member
Author
|
/ba0g the sos failures are tracked in #133175 |
Member
Author
|
/ba-g the sos failures are tracked in #133175 |
radekdoulik
added a commit
that referenced
this pull request
Sep 4, 2026
…stem (#131877) Replaces the hardcoded struct-size table in the CoreCLR wasm P/Invoke generator with crossgen2's real field-layout engine. ## The problem `ManagedToNativeGenerator` computed wasm ABI signature strings from `System.Reflection.MetadataLoadContext`, which has no field-layout engine. Struct sizes came from a 7-entry hardcoded table, and anything outside it was a hard build error: ``` error WASM0067: SignatureMapper: unknown multi-field struct 'X' (fields: N) - add its size to s_knownStructSizes in SignatureMapper.cs ``` Size matters because the CoreCLR interpreter lays struct arguments out inline across 8-byte slots — `TokenToSlotCount` returns `max((size + 7) / 8, 1)` for an `S<N>` token. A wrong `N` misaligns the interpreter frame. Mono's generator needs none of this: its alphabet has no `S`, and it encodes every struct as a pointer. ## The change crossgen2 gains `--generate-portable-callhelpers <dir>`, which writes the three C++ call-helper files directly. It sets up its type system as for a real wasm compilation, scans the input assemblies and emits — no JIT, no R2R image. The option requires `--targetarch wasm` with `--targetos browser|wasi`. The CoreCLR half of the MSBuild task is deleted rather than adapted: `ManagedToNativeGenerator`, `PInvokeCollector`, `PInvokeTableGenerator`, `SignatureMapper`, `InternalCallSignatureCollector`, `InterpToNativeGenerator`. `_CoreCLRGenerateManagedToNative` keeps its name and position in the target graph; its final step changes from `<UsingTask>` to `<Exec>`. The regeneration scripts move next to their output under `src/coreclr/vm/wasm/` and drive `generate-coreclr-helpers.proj`. Mono's generator is untouched. **−2269 lines under `src/tasks`, +1541 under `ILCompiler.ReadyToRun/PortableCallHelpers`.** A move, not an addition: the second implementation of wasm ABI lowering is gone, and the one that remains is the one the JIT interface itself calls. Sizes are computed, not enumerated. The only change to `WasmLowering` is widening `WasmValueTypeToSigChar` from `private` to `internal`. ### Naming Portable entry points exist for any platform that cannot generate code at run time; wasm is the only one today. Per [review feedback](#131877) nothing in this functionality is named after wasm. Symbols shared by the runtime and the generated tables were renamed on both sides at once: | before | after | |---|---| | `StringToWasmSigThunk` | `StringToPortableSigThunk` | | `g_wasmThunks[Count]` | `g_portableCallHelperThunks[Count]` | | `wasm_ret_S<n>` | `portable_callhelper_ret_S<n>` | What keeps wasm in its name is what is genuinely about wasm: the ABI in `WasmLowering`, the `--targetos browser|wasi` requirement, and the wasm-specific corerun the runtime tests link. ### Finding crossgen2 Three paths, tried in order: - **Override** — `$(PortableCallHelpersGeneratorPath)`, which must name a crossgen2 executable. - **In repo** — `$(Crossgen2InBuildDir)`; crossgen2 is built unconditionally by the `clr` subset. - **Out of repo** — the `wasm-tools` workload declares the existing `Microsoft.NETCore.App.Crossgen2.<host-rid>` pack, whose `Sdk/Sdk.props` defines `$(Crossgen2ToolPath)`. ~12.5 MB. The SDK resolves this pack only when `PublishReadyToRun` is set, which wasm CoreCLR apps never set — hence the workload. dotnet/sdk#56119 proposes acquiring it directly instead, which would let the workload entry go. If none of the three resolve, the targets error rather than passing an empty path down. The pack is named for the machine that *runs* crossgen2, not the target: generation never loads the JIT, so a host-targeting crossgen2 answers wasm ABI questions correctly. The workload-testing legs do not set `$(BuildHostTools)`, so nothing produced a crossgen2 pack for their local package feed. (The perf browser-wasm leg does produce one, but only because it opts in — #133143.) `Microsoft.NETCore.App.Crossgen2.Host.sfxproj` pins the RID to the build host, and is now built by the CoreCLR browser-wasm leg behind `$(BuildCrossgen2HostPackForWorkloadTesting)`, guarded on `$(BuildHostTools)` being unset so the two paths can never emit the same package id twice. The official build is untouched — it already publishes this pack from the host platform legs. ## Behaviour changes **`WASM0066` is removed.** The old task warned for every `DllImport` whose module did not resolve to a linked-in native library — a CoreCLR-only divergence that fires on ordinary cross-platform code never executed on wasm (#131874 reports ten from SkiaSharp alone on a shipped Preview 7 SDK). In-tree it had already accumulated two `NoWarn` suppressions and a `WarnOnUnresolvedPInvokeModules=false`; all three go, along with the `--no-warn-unresolved-directpinvoke` opt-out that existed only to silence it. An unresolved module is not knowably wrong at build time: `callhelpers_pinvoke_override` returns `nullptr` on a miss, so a call that actually happens throws `DllNotFoundException` naming the module, as on every other platform. Dropping a warning is strictly loosening. **`WASM0065` is added, as a message.** Per module, when it declares P/Invokes without `[assembly: DisableRuntimeMarshalling]`, since the generated helpers assume signatures cross unmarshalled. A message rather than a warning: it reports something the app author often cannot fix, and as a warning it would fail `-warnaserror` builds. Four fire across the 181 framework assemblies. **Exported callbacks with an ambiguous name are rejected.** An export wrapper resolves its `MethodDesc` through `LookupUnmanagedCallersOnlyMethodByName`, which takes the first `[UnmanagedCallersOnly]` method of matching name and compares no signature — so two exported overloads resolve to the same method and one wrapper calls it with the wrong arguments. Everything the generator controls carries the arity, so the existing duplicate-key and duplicate-symbol checks both pass. Generation now fails instead, naming both signatures. Only exports: a non-exported callback is found by the arity-aware key and never reaches the name lookup. ## Known limitations - **wasi has no out-of-repo acquisition path.** `wasi-experimental` extends `microsoft-net-runtime-mono-tooling`, not `wasm-tools`, so it picks up no crossgen2 pack; the targets error explicitly there. Browser is the shipping wasm/CoreCLR target. - **Reverse thunks allocate one `int64_t` slot per managed parameter**, while a by-value struct argument occupies `ceil(size/8)` interpreter slots. No `[UnmanagedCallersOnly]` callback in CoreLib or the libraries takes a by-value struct, so nothing exercises this. The old generator rejected such callbacks with `WASM0067`; this one accepts them, so user code would get a bad thunk rather than a diagnostic. - **`'V'` (v128) has no case in the C++ emission helpers.** Pre-existing; fails loudly. - **Multi-slot types (`Int128`, `Vector256`, …) are rejected at the thunk emitter** rather than at the interop boundary, so the diagnostic differs from the old `WASM0068`. Still a clean `crossgen2 : error :` with exit 1. No such P/Invoke exists today. - Does not re-enable the tests disabled in #131811 (#133187), and does not address gaps #3–#7 there. ## Verification - **Regeneration reproduces the committed helpers byte for byte**, apart from the rename above, with zero `WASM0001`/`WASM0060`/`WASM0061`/`WASM0062` warnings across a full CoreLib+libraries scan. (The checked-in P/Invoke table is already slightly stale against `main` independently of this PR; that drift is left alone.) - `WasmArgumentLayoutTests` goes from 17 to 22 test methods. The two covering the rejection above were checked against a disabled check, so they test it rather than agree with it. - `clr+libs` builds clean for `browser` and `wasi`; `WasmAppBuilder` still builds for both `net11.0` and `net472`. - Both flavors build end to end from the in-tree samples, with per-architecture native payloads, a non-PE file and duplicate-culture satellites injected into the bundle. - The renamed runtime contract was checked by building: `libcoreclr_static.a` exports `g_portableCallHelperThunks` and no `g_wasmThunks`, and the browser sample links its generated tables against it. Contributes to #131811, closing blocking gap #1 and the struct half of gap #2: a 3-int and a 5-double struct in `[UnmanagedFunctionPointer]` signatures now resolve to `vS12` / `S12i` / `vS40i`, where all three previously threw `NotSupportedException`. > [!NOTE] > This pull request description was drafted with the help of GitHub Copilot. --------- Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Co-authored-by: Jan Kotas <jkotas@microsoft.com> Copilot-Session: f6d6e5a4-5b25-4198-b42d-d5b2dc781f47
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
CrossBuildHostToolsproperty that defaults tofalseValidation
ProjectToBuildwith the repository SDK and confirmed the default host child remainsCrossBuild=falseCrossBuild=true, withClrWasmJitSubset=trueandCLR_CROSS_COMPONENTS_BUILD=1CrossBuildunsetclr.crossarchtools+clr.tools+packsgraph includes the cross-built WASM JIT and host Crossgen2 packgit diff --checkNative GLIBC dependency inspection was not run locally because the development workspace is macOS without the Linux webassembly container. A
runtime-wasm-perfrun is required to verify the packaged JIT against Ubuntu 22.04 end to end.Note
This pull request description was generated with GitHub Copilot.