GHC head, profiling with -O2 does not work

Ben Gamari ben at
Mon May 24 02:07:46 UTC 2021

Harendra Kumar <harendra.kumar at> writes:

> Hi,
> I am trying to build a small program with profiling using a ghc built from
> haskell gitlab master branch. When I use -O2 I run into:
> $ ghc/inplace/bin/ghc-stage2 --make -O2 -prof -fprof-auto -rtsopts Main.hs
> Linking Main ...
> ./StreamD.o(.text+0x1b9f2): error: undefined reference to
> 'StreamK_mkStreamFromStream_HPC_cc'
> ./MArray.o(.text+0xbe83): error: undefined reference to
> 'StreamK_mkStreamFromStream_HPC_cc'
> Main.o(.text+0x6fdb): error: undefined reference to
> 'StreamK_mkStreamFromStream_HPC_cc'
> collect2: error: ld returned 1 exit status
> `cc' failed in phase `Linker'. (Exit code: 1)
> It builds fine without the -O2 option. On ghc-8 it builds fine even with
> -O2. Is that a bug in the head GHC or just something to do with how I built
> it?
Hmm, that indeed looks bad. Could you open a ticket?


- Ben
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