Modifying the "StgHeader" struct

[Rodrigo Mesquita]

Hello Adithya,

This sounds just like what has been implemented as the default mode for eras profiling: https://well-typed.com/blog/2024/01/ghc-eras-profiling — which tracks an “era” for each heap object — and, by default, uses a major garbage collection as the increment trigger.
Could you check it out and see if it would supersede what you are trying to do?

Cheers,
Rodrigo

> On 25 Feb 2024, at 12:58, Adithya Kumar <adi.obilisetty at gmail.com> wrote:
> 
> Hello,
> 
> I want to add a field for collecting information about the number of GCs a
> particular heap object survived.
> 
> I've done the following to implement this:
> - Add a field "StgWord gc_id" to struct "StgHeader" and "StgThunkHeader"
> - Update "SET_HDR" macro in "ClosureMacros.h" to update the "gc_id"
> - Update the "closureTypeHeaderSize" function in "Heap/ClosureTypes.hs" to
>   account for that 1 extra word.
> 
> Compilation leads to a segmentation fault. The stage 2 compiler is built. But
> usage of it leads to a segmentation fault.
> 
> Build output:
> ```
> chmod +x                                                     inplace/bin/ghc-stage2
> "inplace/bin/ghc-stage2" -hisuf dyn_hi -osuf  dyn_o -hcsuf dyn_hc -fPIC -dynamic  -O0 -H64m -Wall      -hide-all-packages -package-env - -i -iutils/check-api-annotations/. -iutils/check-api-annotations/dist-install/build -Iutils/check-api-annotations/dist-install/build -iutils/check-api-annotations/dist-install/build/check-api-annotations/autogen -Iutils/check-api-annotations/dist-install/build/check-api-annotations/autogen     -optP-include -optPutils/check-api-annotations/dist-install/build/check-api-annotations/autogen/cabal_macros.h -package-id Cabal-3.2.1.0 -package-id base-4.14.3.0 -package-id containers-0.6.5.1 -package-id directory-1.3.6.0 -package-id ghc-8.10.7.20240224 -Wall -XHaskell2010  -no-user-package-db -rtsopts       -Wnoncanonical-monad-instances  -outputdir utils/check-api-annotations/dist-install/build   -c utils/check-api-annotations/./Main.hs -o utils/check-api-annotations/dist-install/build/Main.dyn_o
> utils/check-api-annotations/ghc.mk:18 <http://ghc.mk:18/>: recipe for target 'utils/check-api-annotations/dist-install/build/Main.dyn_o' failed
> make[1]: *** [utils/check-api-annotations/dist-install/build/Main.dyn_o] Segmentation fault (core dumped)
> Makefile:123: recipe for target 'all' failed
> make: *** [all] Error 2
> ```
> 
> Is there any other place I've missed follow-up modifications?
> 
> I appreciate any help provided.
> 
> Best,
> Adithya
> _______________________________________________
> ghc-devs mailing list
> ghc-devs at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/ghc-devs/attachments/20240225/cc8dd42e/attachment.html>