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| 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/Stg/Syntax.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/Stg/Syntax.hs')
| -rw-r--r-- | compiler/GHC/Stg/Syntax.hs | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/compiler/GHC/Stg/Syntax.hs b/compiler/GHC/Stg/Syntax.hs index 4956920fb1..d1b44e94fa 100644 --- a/compiler/GHC/Stg/Syntax.hs +++ b/compiler/GHC/Stg/Syntax.hs @@ -74,6 +74,7 @@ import Data.ByteString ( ByteString ) import Data.Data ( Data ) import Data.List ( intersperse ) import GHC.Core.DataCon +import GHC.Types.Basic ( Levity(..) ) import GHC.Types.ForeignCall ( ForeignCall ) import GHC.Types.Id import GHC.Types.Name ( isDynLinkName ) @@ -165,10 +166,10 @@ isDllConApp platform ext_dyn_refs this_mod con args -- -- The coercion argument here gets VoidRep isAddrRep :: PrimRep -> Bool -isAddrRep AddrRep = True -isAddrRep LiftedRep = True -isAddrRep UnliftedRep = True -isAddrRep _ = False +isAddrRep AddrRep = True +isAddrRep (BoxedRep Lifted) = True +isAddrRep (BoxedRep Unlifted) = True +isAddrRep _ = False -- | Type of an @StgArg@ -- |