Am Fr., 19. Nov. 2021 um 01:09 Uhr schrieb Ben Gamari <ben@smart-cactus.org>:

Artem Pelenitsyn <a.pelenitsyn@gmail.com> writes:

> Another question would be where do I read about Haskell-native stack
> unwinder. The issue and MR Ben referenced have descriptions, but the MR
> didn't touch anything inside `docs` which is a bit scary. Are there any
> good recourses to dive into it besides the source code in the MR?
>
Indeed the user's guide documentation surrounding info table provenance
should be updated to note this new capability.

 

Hey Ben, Hey Artem, Hey all,

Thanks for bringing this up! I'll add some documentation to the user's guide and will likely write a blog post covering the "material" from notes in a more approachable way.

Two details to note regarding the IPE based backtrace mechanism:

- It's based on return frames on the STG stack. So, it doesn't work for trivial programs. A return frame is produced when the scrutinee of a case expression is evaluated.
The test [1] shows a working example.

- To get backtraces containing references in libraries, those have to be compiled with `-finfo-table-map`, too.

Now that I've got the attention of many GHC-Devs: A big Thank-You! goes to Ben and Matthew that were always reachable and always very helpful during the whole development process of this feature!

Best regards,

Sven

[1] - https://gitlab.haskell.org/ghc/ghc/-/blob/aed98ddaf72cc38fb570d8415cac5de9d8888818/testsuite/tests/rts/decodeMyStack.hs