[wasm][wasi] CoreCLR-WASI bring-up fixes: Checked build, PAL stubs, getHelperFtn, call helpers

[pavelsavara]

Contributes to #133240

A set of CoreCLR-on-WASI bring-up fixes discovered while getting JIT/CodeGenBringUpTests to run under wasmtime in a Checked build. Each is an independent commit.

Commits

• Fix WASI PAL stubs for the CoreCLR Checked build — pal/src/debug/debug.cpp is excluded on WASI, so PAL_ProbeMemory (referenced by vm/debughelp.cpp under TARGET_UNIX) had no definition and wasm-ld failed with an undefined symbol in Checked (the reference is dead-stripped in Release). Provide it in arch/wasm/stubs.cpp next to the other replacements for the excluded PAL sources, and drop the now-dead TARGET_WASI branch in debug.cpp. Also: the WASI DebugBreak stub no longer calls _ASSERT — AssertBreak calls DebugBreak, so asserting recursed until the stack was exhausted and masked the original assert.
• Do not pass wasm EH flags to the MSVC cross-components build — guard the WASI exception-handling compile/link flags with NOT CLR_CROSS_COMPONENTS_BUILD (mirroring the browser block) so -fwasm-exceptions / -mllvm -wasm-use-legacy-eh don't leak onto the MSVC host-tool compiles (cl warning D9002).
• Allow interpreter-preferred JIT helpers in getHelperFtn — an IL-based dynamic helper (e.g. VirtualFunctionPointer) can run interpreted with no native code even when ReadyToRun is enabled. Guard the published-native-code assert with HasNativeEntryPoint so it no longer asserts inside GetActualCode.
• Regenerate WASI call helpers — regenerated callhelpers-interp-to-managed.cpp / callhelpers-pinvoke.cpp with the crossgen2 PortableCallHelpers generator over the WASI framework closure.

Status

With these applied, a Checked WASI corerun now boots and executes interpreted managed code through to ExecuteAssembly entry-point launch. Remaining bring-up work (entry-point resolution and the EH stack-frame-iterator path) is being investigated separately. Related tracking: #133124, #133187.

Note

Portions of this PR description were generated with the assistance of GitHub Copilot.

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[Copilot]

🟡 Changes recommended

The new WASI PAL_ProbeMemory stub performs unchecked pointer/size arithmetic that can overflow and incorrectly validate out-of-bounds ranges.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR makes a set of CoreCLR-on-WASI bring-up fixes to improve Checked-build viability and interpreter execution, including providing missing PAL stubs, tightening build-flag gating for WASI exception handling, relaxing a ReadyToRun-related assert for interpreter-preferred helpers, and regenerating WASI call-helper tables.

Changes:

• Add/adjust WASI-specific PAL stubs (notably DebugBreak and PAL_ProbeMemory) while simplifying non-WASI PAL code paths.
• Gate WASI wasm-exception compile/link flags to avoid leaking them into cross-components host-tool builds.
• Regenerate WASI call-helper thunks and P/Invoke override tables; update getHelperFtn to allow interpreter-preferred IL helpers even when R2R is enabled.

File summaries

File	Description
src/coreclr/vm/wasm/wasi/callhelpers-pinvoke.cpp	Update generated WASI P/Invoke override table (remove one compression entry and fix counts).
src/coreclr/vm/wasm/wasi/callhelpers-interp-to-managed.cpp	Regenerate generated WASI interp-to-managed portable signature thunks.
src/coreclr/vm/jitinterface.cpp	Relax R2R/native-code assertion for IL-based dynamic helpers by guarding with HasNativeEntryPoint.
src/coreclr/pal/src/debug/debug.cpp	Remove WASI-specific PAL_ProbeMemory branch from a file that is excluded on WASI.
src/coreclr/pal/src/arch/wasm/stubs.cpp	Add WASI replacements for debug output and PAL_ProbeMemory.
eng/native/configureplatform.cmake	Correct host-vs-target WASI detection and guard WASI EH flags for non-cross-components builds.

Review details

• Files reviewed: 6/6 changed files
• Comments generated: 1
• Review effort level: Lite

[pavelsavara]

/ba-g failure is #133255