Description

vapier

opened on Jul 12, 2026

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Running some configure scripts crashes many times due to clang implicitly running wasm-opt for me. I'm using wasi-sdk 33.0 fwiw. I suspect the mismatch in declared prototype & actual function definition is upsetting the tool.

attaching one example program

$ wasm-opt --version
wasm-opt version 130 (version_130)

$ wasm-opt conftest -O2 -o x 
[parse exception: popping from empty stack (at 0:456)]
Fatal: error parsing wasm (try --debug for more info)

$ wasm-opt conftest -O2 -o x --debug
reading...
reading binary from conftest
Loading 'conftest'...
[parse exception: popping from empty stack (at 0:456)]
getNumCores: 4
Assertion failed: *currp (/src/src/wasm-traversal.h: pushTask: 286)
Aborted (core dumped)

conftest.gz

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1. tlively commented on Jul 13, 2026

   

   tlively

   on Jul 13, 2026

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   Binaryen and wasm-tools both agree that this module is invalid, so there is no Binaryen bug here. It does sound plausible that a mismatch in prototype and definition signatures would cause this, but then the bug would be in the original program and not even in LLVM.
2. vapier commented on Jul 13, 2026

   

   vapier

   on Jul 13, 2026

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   at the very least, the diagnostics shown to users are bad. an assert/abort/coredump is not how well defined tools behave.

   if the runtime wants to assert matching function definitions, then somewhere in the stack that diagnostic should show up.

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