diff options
| author | Ben Gamari <ben@smart-cactus.org> | 2022-10-13 18:17:13 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2022-10-19 10:06:10 -0400 |
| commit | 6148bd126c4602d011e7dd458288c02db1c16dc6 (patch) | |
| tree | 0cebae532fef06af2374485530549273cee14bac /compiler/GHC/StgToByteCode.hs | |
| parent | 1ef412dde750d4ffd01a332e555ed4503d4eda85 (diff) | |
| download | haskell-wip/T22291.tar.gz | |
codeGen: Allow levity-polymorphic primop resultswip/T22291
Consider a program such as:
```haskell
foo :: forall (lev :: Levity) (a :: TYPE (BoxedRep lev)). Addr# -> (# a #)
foo x = addrToAny# x
```
While this program is accepted by the type-checker, the code generator would previously
choke on it due the levity polymorphism of `foo`'s result. Specifically,
`boxedRepDataCon` would fail as it was unable to determine the result's `PrimRep`
while trying to identify its Cmm type:
```
<no location info>: error:
panic! (the 'impossible' happened)
GHC version 9.5.20220906:
boxedRepDataCon
[lev_ayH]
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/GHC/Utils/Panic.hs:188:37 in ghc:GHC.Utils.Panic
pprPanic, called at compiler/GHC/Builtin/Types.hs:1629:9 in ghc:GHC.Builtin.Types
prim_rep_fun, called at compiler/GHC/Builtin/Types.hs:1618:44 in ghc:GHC.Builtin.Types
fun, called at compiler/GHC/Types/RepType.hs:615:5 in ghc:GHC.Types.RepType
runtimeRepPrimRep, called at compiler/GHC/Builtin/Types.hs:1660:20 in ghc:GHC.Builtin.Types
prim_rep_fun, called at compiler/GHC/Builtin/Types.hs:1655:64 in ghc:GHC.Builtin.Types
fun, called at compiler/GHC/Types/RepType.hs:615:5 in ghc:GHC.Types.RepType
runtimeRepPrimRep, called at compiler/GHC/Types/RepType.hs:585:5 in ghc:GHC.Types.RepType
kindPrimRep, called at compiler/GHC/Types/RepType.hs:537:18 in ghc:GHC.Types.RepType
typePrimRep, called at compiler/GHC/StgToCmm/Utils.hs:305:58 in ghc:GHC.StgToCmm.Utils
newUnboxedTupleRegs, called at compiler/GHC/StgToCmm/Prim.hs:1701:33 in ghc:GHC.StgToCmm.Prim
```
Here we fix this by modifying `PrimRep` to reflect the fact that we may
know that a value is boxed without knowing its particular levity:
```haskell
data PrimRep = BoxedRep Levity | IntRep | ...
```
This allows `kindPrimRep (TYPE (BoxedRep lev))` to return
`BoxedRep _|_`, which is enough information for the code generator to
compile `foo`.
Fixes #22291.
Diffstat (limited to 'compiler/GHC/StgToByteCode.hs')
| -rw-r--r-- | compiler/GHC/StgToByteCode.hs | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/compiler/GHC/StgToByteCode.hs b/compiler/GHC/StgToByteCode.hs index be2d6a82fa..879eaa1f61 100644 --- a/compiler/GHC/StgToByteCode.hs +++ b/compiler/GHC/StgToByteCode.hs @@ -1107,8 +1107,8 @@ layoutTuple profile start_off arg_ty reps = usePlainReturn :: Type -> Bool usePlainReturn t | isUnboxedTupleType t || isUnboxedSumType t = False - | otherwise = typePrimRep t == [LiftedRep] || - (typePrimRep t == [UnliftedRep] && isAlgType t) + | otherwise = typePrimRep t == [BoxedRep Lifted] || + (typePrimRep t == [BoxedRep Unlifted] && isAlgType t) {- Note [unboxed tuple bytecodes and tuple_BCO] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -1451,8 +1451,7 @@ primRepToFFIType platform r AddrRep -> FFIPointer FloatRep -> FFIFloat DoubleRep -> FFIDouble - LiftedRep -> FFIPointer - UnliftedRep -> FFIPointer + BoxedRep _ -> FFIPointer _ -> pprPanic "primRepToFFIType" (ppr r) where (signed_word, unsigned_word) = case platformWordSize platform of @@ -1477,8 +1476,7 @@ mkDummyLiteral platform pr AddrRep -> LitNullAddr DoubleRep -> LitDouble 0 FloatRep -> LitFloat 0 - LiftedRep -> LitNullAddr - UnliftedRep -> LitNullAddr + BoxedRep _ -> LitNullAddr _ -> pprPanic "mkDummyLiteral" (ppr pr) |