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| author | Matthew Pickering <matthewtpickering@gmail.com> | 2021-10-08 09:24:20 +0100 |
|---|---|---|
| committer | Matthew Pickering <matthewtpickering@gmail.com> | 2021-10-11 22:50:42 +0100 |
| commit | 6d23d0fcfe8ff8111b142f090ab88c7c2fa0a8a0 (patch) | |
| tree | e400475f5b7932beb39e3865b626b8eba6a9c8e8 | |
| parent | 245ab1662edd91a82c17de110c79450fec3f7b82 (diff) | |
| download | haskell-6d23d0fcfe8ff8111b142f090ab88c7c2fa0a8a0.tar.gz | |
Make the OccName field of NotOrphan strict
In GHCi, by default the ModIface is not written to disk, this can
leave a thunk which retains a TyCon which ends up retaining a great deal
more on the heap.
For example, here is the retainer trace from ghc-debug.
```
...
many other closures
...
<TyCon:GHC.Core.TyCon:compiler/GHC/Core/TyCon.hs:1755:34-97>
Just 0x423162aaa8 <Maybe:GHC.Core.TyCon:compiler/GHC/Core/TyCon.hs:(1936,11)-(1949,13)>
FamilyTyCon 0x4231628318 0x4210e06260 0x4231628328 0x4231628340 0x421730a398 0x4231628358 0x4231628380 0x4231628390 0x7f0f5a171d18 0x7f0f7b1d7850 0x42316283a8 0x7f0f7b1d7830 <TyCon:GHC.Core.TyCon:compiler/GHC/Cor
e/TyCon.hs:1948:30-32>
_thunk( ) 0x4231624000 <OccName:GHC.Iface.Make:compiler/GHC/Iface/Make.hs:724:22-43>
NotOrphan 0x42357d8ed8 <IsOrphan:GHC.Iface.Make:compiler/GHC/Iface/Make.hs:724:12-43>
IfaceFamInst 0x4210e06260 0x42359aed10 0x4210e0c6b8 0x42359aed28 <IfaceFamInst:GHC.Iface.Make:>
```
Making the field strict squashes this retainer leak when using GHCi.
| -rw-r--r-- | compiler/GHC/Core.hs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/GHC/Core.hs b/compiler/GHC/Core.hs index ecd9a6ee00..fb93fc093f 100644 --- a/compiler/GHC/Core.hs +++ b/compiler/GHC/Core.hs @@ -942,7 +942,7 @@ type MOutCoercion = MCoercion -- See Note [Orphans] data IsOrphan = IsOrphan - | NotOrphan OccName -- The OccName 'n' witnesses the instance's non-orphanhood + | NotOrphan !OccName -- The OccName 'n' witnesses the instance's non-orphanhood -- In that case, the instance is fingerprinted as part -- of the definition of 'n's definition deriving Data |