Update libunwind from LLVM 20.1.8 to 21.1.8 #26036
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llvm/llvm-project#125412 removed parameter names to suppress `-Wunused-parameter` in their own build system. As a result now we have this error: ```console ../../../system/lib/libunwind/src/Unwind-wasm.c:105:62: error: omitting the parameter name in a function definition is a C23 extension [-Werror,-Wc23-extensions] 105 | _LIBUNWIND_EXPORT void _Unwind_SetIP(struct _Unwind_Context *, uintptr_t) {} | ``` We have three ways to fix it? 1. Re-add parameter names. But this will later clash with llvm/llvm-project#125412. 2. Add `-std=c23` to the cflags. But this only applies to .c files and our `get_cflags` function in `system_libs.py` doesn't take a file name so we can't apply different cflags depending on the file extensions. While it's possible to add the filename paramater to `get_cflags`, it is a bigger refactoring. 3. Suppress the warning using `-Wno-c23-extension`. This does 3, which is the quickest. But eventually we may need to change what llvm/llvm-project#125412 did.
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Does upstream build with std=c23? |
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It does, but libunwind has both .c and .cpp files so we can't unilaterally build them with |
aheejin
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How can I get both of them wrong?
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Can we land this as is then? |
sbc100
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Jan 13, 2026
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lgtm, sorry I didn't understand the c23 warning things initially!
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| cflags = ['-Oz', '-fno-inline-functions', '-D_LIBUNWIND_HIDE_SYMBOLS'] | ||
| cflags = ['-Oz', '-fno-inline-functions', '-D_LIBUNWIND_HIDE_SYMBOLS', | ||
| '-Wno-c23-extensions'] |
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Can you add a comment here to remove once llvm/llvm-project#175776 lands?`
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This updates libunwind from 20.1.8 to LLVM 21.1.8:
https://github.com/llvm/llvm-project/releases/tag/llvmorg-21.1.8
Additional change:
-Wno-c23-extensionsto libunwind's cflags: 0070206Silence -Wunused-parameter warnings in Unwind-wasm.c llvm/llvm-project#125412 removed parameter names to suppress
-Wunused-parameterin their own build system, but this causes these errors instead for us: