libbacktrace fails to parse debug symbols on macOS ARM64 with Apple Clang 17

[sangbida]

Hello,
I'm encountering the following error when using libbacktrace with a binary compiled on macOS:

lightningd/lightningd: libbacktrace: DW_FORM_addrx value out of range
lightningd/lightningd: libbacktrace: failed to read executable information

I'm running:
macOS 15.4.1 (24E263)
Apple clang version 17.0.0 (clang-1700.0.13.5)
Target: arm64-apple-darwin24.4.0
libbacktrace version: Latest master (commit 7939218)

I think libbacktrace seems to work fine on Core Lightning on Linux but doesn't work on MacOS. I get the above error when I try to compile core lightning and run a broken test.

What I've tried so far:

• Updated the libbacktrace submodule on core lightning to include this commit
• Modified debug flags in the configure script to use -gdwarf-4 instead of the default DWARF version.

CDEBUGFLAGS="-std=gnu11 -g -gdwarf-4 -fstack-protector-strong"

• Added dsymutil support in the main Makefile

I've added my changes to the config and makefile here: sangbida/lightning@8e459d3

Despite these changes, the "DW_FORM_addrx value out of range" error persisted 😭 Please let me know if there's anything that I'm doing obviously wrong here, which I hope I am because I would dearly love to resolve this!

[ianlancetaylor]

I don't see anything obviously wrong.

I don't have access to a macOS ARM64 machine so I don't have a way to debug this. The first step would be to confirm that your executable has a __debug_addr section. If it does, perhaps you can run the program under the debugger and set a breakpoint on the error callback routine to see what the values are that are out of range.

[sangbida]

Okay, so it works now! However, I didn't make any further changes to the config beyond that point. Not really sure what changed? But my changes are here on this PR: ElementsProject/lightning#8431 and backtraces seem to work!

[ianlancetaylor]

Glad it's working for you. Sounds like there is a bug somewhere for LLVM with -gdwarf-5. Leaving this open in case somebody with access to macOS arm64 is able to investigate.