Revert "Guard unused llvm-libunwind symbols to avoid duplicates on Android"

[MichalStrehovsky]

Reverts #128667

Seeing crashes on ARM32 in libunwind code, suspect range is d1b43a3...a73aedb so this is a prime suspect.

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[MichalStrehovsky]

/azp run runtime-nativeaot-outerloop

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🤖 Copilot Code Review — PR #128828

Holistic Assessment

Motivation: Justified. ARM32 crashes in libunwind code are traced to the commit range that includes #128667. Reverting the prime suspect is the correct first response to a runtime crash.

Approach: This is a clean, mechanical revert of #128667. The approach is appropriate — revert to restore stability, then re-investigate the Android symbol conflict fix (#121172) with an approach that doesn't break ARM32.

Summary: ✅ LGTM. This is a faithful revert of all 7 files changed in #128667. The diff is the exact inverse of the original PR. No new code, no partial reverts, no manual edits — just a clean undo. The labels (NO-MERGE, NO-REVIEW, draft) indicate the author is running outerloop CI to confirm this fixes the ARM32 crashes before merging.

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Detailed Findings

✅ Revert Completeness — All changes from #128667 are fully reverted

Verified that all 7 files modified in #128667 are reverted:

• CMakeLists.txt: _LIBUNWIND_NATIVEAOT → back to _LIBUNWIND_DISABLE_ZERO_COST_APIS
• UnixNativeCodeManager.cpp: UnwindHelpers::FindUnwindSections() → back to LocalAddressSpace::sThisAddressSpace.findUnwindSections()
• UnwindHelpers.cpp: Removes the added FindUnwindSections wrapper
• UnwindHelpers.h: Removes the added declaration
• llvm-libunwind-version.txt: Removes the patch tracking entry
• Unwind-EHABI.cpp: Removes _LIBUNWIND_NATIVEAOT guards around C++ exception dispatch functions
• libunwind.cpp: Removes _LIBUNWIND_NATIVEAOT guards around the public API

Additions (3) + deletions (26) match the inverse of #128667's additions (26) + deletions (3).

✅ No Collateral Changes — Revert is isolated

No unrelated modifications, no style changes, no additional fixes bundled in.

💡 Follow-up: Android NDK r29 symbol conflict (#121172) will need a new fix

The original PR was fixing real symbol conflicts on Android NDK r29. After this revert lands, the issue will resurface. The next attempt should ensure ARM32 EHABI paths remain functional — the original approach of guarding out the C++ exception dispatch functions in Unwind-EHABI.cpp likely broke ARM32 unwinding since those __aeabi_unwind_cpp_pr* personality routines may be needed even when NativeAOT doesn't use the public unw_* API directly.

Generated by Code Review for issue #128828 · ● 2M · ◷

[Copilot]

Pull request overview

This PR reverts #128667, which had guarded out llvm-libunwind public symbols for NativeAOT via a _LIBUNWIND_NATIVEAOT define. The revert is motivated by ARM32 crashes observed in libunwind code, suspected to originate from the guarded build.

Changes:

• Removes _LIBUNWIND_NATIVEAOT conditional guards from libunwind.cpp and Unwind-EHABI.cpp, restoring the public unw_*/_Unwind_* APIs and EHABI personality routines.
• Restores the previous CMake definition _LIBUNWIND_DISABLE_ZERO_COST_APIS=1 in place of _LIBUNWIND_NATIVEAOT=1.
• Removes the UnwindHelpers::FindUnwindSections wrapper and reverts the call site to use LocalAddressSpace::sThisAddressSpace.findUnwindSections directly; updates llvm-libunwind-version.txt.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/native/external/llvm-libunwind/src/Unwind-EHABI.cpp	Removes _LIBUNWIND_NATIVEAOT guard around EHABI personality and _Unwind_* APIs.
src/native/external/llvm-libunwind/src/libunwind.cpp	Removes _LIBUNWIND_NATIVEAOT guard around public unw_* API and LocalAddressSpace.
src/native/external/llvm-libunwind-version.txt	Drops the entry for the reverted local patch commit.
src/coreclr/nativeaot/Runtime/unix/UnwindHelpers.h	Removes FindUnwindSections declaration.
src/coreclr/nativeaot/Runtime/unix/UnwindHelpers.cpp	Removes FindUnwindSections implementation.
src/coreclr/nativeaot/Runtime/unix/UnixNativeCodeManager.cpp	Reverts to calling LocalAddressSpace::sThisAddressSpace.findUnwindSections directly.
src/coreclr/nativeaot/Runtime/CMakeLists.txt	Replaces _LIBUNWIND_NATIVEAOT=1 define with _LIBUNWIND_DISABLE_ZERO_COST_APIS=1.

[MichalStrehovsky]

arm32 is green here, so this is confirmed.