Relink browser Wasm ReadyToRun apps

[lewing]

Summary

Browser CoreCLR ReadyToRun publishing now implies WasmBuildNative=true, ensuring Crossgen2 and the generated P/Invoke call-helper table process the same managed closure.

The failure occurred when per-app ReadyToRun compilation classified framework modules such as System.Native as direct while WasmBuildNative=false reused the prebuilt framework-only helper table. Test-only entry points such as SystemNative_GetEUid were then absent from that table and failed during ReadyToRun fixup before the guarded call was reached.

This change:

• preserves the direct-P/Invoke compiler policy introduced by Classify Wasm P/Invokes before R2R codegen #133773, including direct PINVOKE_TARGET codegen;
• makes browser ReadyToRun nested publishes require native relinking, while leaving WASI unchanged;
• preserves explicitly requested VFS payloads in trimmed CoreCLR browser tests without restoring the broad untrimmed dependency set;
• adds a trimmed guarded SystemNative_GetEUid regression;
• updates ReadyToRun WBT coverage and validates custom native modules through the generated --directpinvoke:native-lib response-file entry.

Validation

• Browser clr+libs+host+packs build passed.
• Full trimmed System.Runtime.Extensions.Tests: 8,308 passed, 70 skipped, 0 failed.
• ReadyToRun WBT class: 5/5 passed before the final main rebase; the post-rebase product/library validation passed, while a local WBT rerun was blocked by unrelated missing/rolled-back workload-test packs.
• Custom native P/Invoke execution passed and R2RDump confirmed PINVOKE_TARGET remains for print_line and SystemNative_GetEUid.
• Generated call-helper tables contain DllImportEntry(print_line) and DllImportEntry(SystemNative_GetEUid).

Sequencing

#133656 currently carries a narrow #if NET workaround in AdminHelpers. Whichever PR merges second should remove that workaround so the root fix is the only retained behavior change.

Resolves #133614

Note

This pull request description and change were prepared with GitHub Copilot assistance.

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[Copilot]

Copilot review overview

🟡 Changes recommended

Improve the ReadyToRun-specific relinking error message before approval.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 1

Open (1)

• Add a clear error when ReadyToRun requires native relinking · New

What changed in this PR

Relinks browser CoreCLR Wasm ReadyToRun apps so compilation and native P/Invoke helper generation use the same managed closure.

Changes:

• Requires native relinking for browser ReadyToRun publishes.
• Preserves explicit VFS payloads in trimmed CoreCLR tests.
• Adds guarded P/Invoke and native-module regression coverage.

Review note: the ReadyToRun relinking failure can produce an unhelpful error message when WasmBuildNative=false is explicit (moderate, 3 votes).

File	Description
src/​mono/​wasm/​Wasm.Build.Tests/​ReadyToRunTests.cs	Adds ReadyToRun relinking regression coverage.
src/​mono/​wasm/​Wasm.Build.Tests/​NativeLibraryTests.cs	Validates generated direct-P/Invoke arguments.
src/​mono/​wasm/​testassets/​EntryPoints/​PInvoke/​GuardedFrameworkEntryPoint.cs	Adds the guarded framework P/Invoke regression entry point.
src/​mono/​browser/​build/​BrowserWasmApp.CoreCLR.targets	Enables relinking for browser ReadyToRun publishes.
eng/​testing/​tests.browser.targets	Preserves explicit VFS files in trimmed tests.

[Copilot]

Copilot review overview

🟡 Changes recommended

Three moderate review findings remain unresolved.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 2

Open (2)

• Add negative test for ReadyToRun with WasmBuildNative=false · New
• Add a clear error when ReadyToRun requires native relinking

[Copilot]

Copilot review overview

🔵 Needs a closer look

The nested ReadyToRun opt-out path can emit a duplicate generic diagnostic and needs conditional handling.

Review effort: Lite
Findings: None

Resolved since last review (2)

• Add negative test for ReadyToRun with WasmBuildNative=false
• Add a clear error when ReadyToRun requires native relinking

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Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
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[jkotas]

What is the cost of auto-enabling relink for ReadyToRun?

It doesn’t seem right to me to auto-enable relinking for ReadyToRun solely to accommodate tests that represent invalid user code.