Re: Modifying the "StgHeader" struct

Hi Adithya, It seems that eras profiling mode allows you to determine this information. In eras profiling the era the object is created is stored in the profiling header, you can automatically increment the era with the --automatic-era-increment at each major collection, you can work out "how many collections an object has been live" by subtracting the current era from the era the object was created. Cheers, Matt On Sun, 25 Feb 2024, 15:43 Csaba Hruska, wrote:

Hi, Are you using profiling mode? Regards, Csaba

On Sun, Feb 25, 2024 at 1:59 PM Adithya Kumar 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: 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@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

_______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs