<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Hello Adithya,<div><br></div><div>This sounds just like what has been implemented as the default mode for eras profiling: <a href="https://well-typed.com/blog/2024/01/ghc-eras-profiling">https://well-typed.com/blog/2024/01/ghc-eras-profiling</a> β which tracks an βeraβ for each heap object β and, by default, uses a major garbage collection as the increment trigger.</div><div>Could you check it out and see if it would supersede what you are trying to do?</div><div><br></div><div>Cheers,</div><div>Rodrigo</div><div><div><br><blockquote type="cite"><div>On 25 Feb 2024, at 12:58, Adithya Kumar <adi.obilisetty@gmail.com> wrote:</div><br class="Apple-interchange-newline"><div><div dir="ltr"><div>Hello,<br></div><div><br></div><div>I want to add a field for collecting information about the number of GCs a</div>particular heap object survived.<br><br>I've done the following to implement this:<br>- Add a field "StgWord gc_id" to struct "StgHeader" and "StgThunkHeader"<br>- Update "SET_HDR" macro in "ClosureMacros.h" to update the "gc_id"<br>- Update the "closureTypeHeaderSize" function in "Heap/ClosureTypes.hs" to<br> account for that 1 extra word.<br><br>Compilation leads to a segmentation fault. The stage 2 compiler is built. But<br>usage of it leads to a segmentation fault.<br><br>Build output:<br>```<br>chmod +x inplace/bin/ghc-stage2<br>"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<br>utils/check-api-annotations/<a href="http://ghc.mk:18/">ghc.mk:18</a>: recipe for target 'utils/check-api-annotations/dist-install/build/Main.dyn_o' failed<br>make[1]: *** [utils/check-api-annotations/dist-install/build/Main.dyn_o] Segmentation fault (core dumped)<br>Makefile:123: recipe for target 'all' failed<br>make: *** [all] Error 2<br>```<br><br>Is there any other place I've missed follow-up modifications?<br><br><div>I appreciate any help provided.</div><div><br></div>Best,<br>Adithya<br></div>
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