libunwind parseFDEInstructions segfaults due to a zero cieInfo

[xxchan]

I've posted the issue on discourse before. Not sure which place is better. More context there https://discourse.llvm.org/t/libunwind-parsefdeinstructions-segfaults-at-null-pointer/69858/

I have few knowledge about compiler and not sure whether it's libunwind or the compiler(rustc)'s fault. Any suggestion about how to diagnose such issues would be appreciated. 🙏

---

(in parseFDEInstructions)

(ParseInfo[2]) parseInfoArray = {
  [0] = (instructions = 0, instructionsEnd = 4467765419, pcoffset = 18446744073709551615)
  [1] = (instructions = 4468701376, instructionsEnd = 7423526062, pcoffset = 4206506293)
}

This instructions = 0 leads to the segfault

It is cieInfo.cieInstructions

cieInfo = 0x0000000170407750: {
  cieStart = 4467765419
  cieLength = 0
  cieInstructions = 0
  pointerEncoding = '\0'
  lsdaEncoding = '\xff'
  personalityEncoding = '\0'
  personalityOffsetInCIE = '\0'
  personality = 0
  codeAlignFactor = 0
  dataAlignFactor = 0
  isSignalFrame = false
  fdesHaveAugmentationData = false
  returnAddressRegister = '\0'
  addressesSignedWithBKey = false
  mteTaggedFrame = false
}

[xxchan]

Original context: rust-lang/rust#104388

To reproduce: (need Rust toolchain and LLVM installed by Homebrew, M1 Mac)

git clone https://github.com/risingwavelabs/risingwave && cd risingwave
git checkout 7e0c548
./risedev p