Implementing a new Primop, stage1 panic

Simon Marlow marlowsd at
Tue Oct 18 11:25:13 CEST 2011

On 17/10/2011 20:11, Paul Monday wrote:
> Fascinating! I added the switch, figured I needed to clean everything to
> see the whole stack and whammo, everything worked.
> I wonder if the build is missing a dependency check along the way, I'll
> have to keep a close eye as I modify files now.
> Thanks for the tip!

I think adding a primop is something that does need a 'make clean', at 
least in the libraries and stage2.  The reason is that you changed the 
interface to GHC.Prim, which is a magic internal module in GHC, and GHC 
doesn't track changes to that module.  In principle GHC itself should 
generate a hash of the contents of GHC.Prim so that it could recompile 
correctly when the contents of GHC.Prim changes, but currently I think 
it just uses zero for the hash.

I've just added this to the end of


> Paul Monday
> Parallel Scientific, LLC.
> paul.monday at <mailto:paul.monday at>
> On Oct 17, 2011, at 8:00 AM, Simon Peyton-Jones wrote:
>> Paul
>> Always switch on -dcore-lint; it’s a self-checker for types, and
>> usually nails an error much closer to the source.
>> Simon
>> *From:*glasgow-haskell-users-bounces at
>> <mailto:glasgow-haskell-users-bounces at>
>> [mailto:glasgow-haskell-users-bounces at]*On Behalf Of*Paul
>> Monday
>> *Sent:*16 October 2011 16:54
>> *To:*glasgow-haskell-users at
>> <mailto:glasgow-haskell-users at>
>> *Subject:*Implementing a new Primop, stage1 panic
>> (Reposting since this got cross-posted sort of oddly and I wasn't
>> subscribed yet)
>> I'm having an odd problem as I try to define my own primop, it seems
>> that some docs may be out of date with respect to all of the touch
>> points for a simple primop addition. I've followed what the various
>> wiki pages have to offer (primarily
>> and
>> success. I even unraveled my PrimOp to be, basically, an exact copy of
>> another PrimOp without luck.
>> The primop I'm attempting to add is now very, very simple and copies
>> FloatAddOp exactly so there must be an additional file I have to
>> modify before the primop is "completely" added.
>> Here are my simple modifications:
>> ./compiler/prelude/primops.txt.pp
>> primop FloatVAddOp "plusFloatVec#" Dyadic
>> Float# -> Float# -> Float#
>> with commutable = True
>> ./compiler/codeGen/CgPrimOp.hs
>> translateOp FloatVAddOp= Just (MO_F_Add W32)
>> The compiler error is below. I have the feeling that an interface is
>> not being built somewhere … this must be a simple one but I can't find
>> any references to this error anywhere … has anyone seen this one
>> before?????
>> "inplace/bin/ghc-stage1" -H64m -O0 -fasm -package-name
>> ghc-7.3.20111007 -hide-all-packages -i -icompiler/basicTypes
>> -icompiler/cmm -icompiler/codeGen -icompiler/coreSyn
>> -icompiler/deSugar -icompiler/ghci -icompiler/hsSyn -icompiler/iface
>> -icompiler/llvmGen -icompiler/main -icompiler/nativeGen
>> -icompiler/parser -icompiler/prelude -icompiler/profiling
>> -icompiler/rename -icompiler/simplCore -icompiler/simplStg
>> -icompiler/specialise -icompiler/stgSyn -icompiler/stranal
>> -icompiler/typecheck -icompiler/types -icompiler/utils
>> -icompiler/vectorise -icompiler/stage2/build
>> -icompiler/stage2/build/autogen -Icompiler/stage2/build
>> -Icompiler/stage2/build/autogen -Icompiler/../libffi/build/include
>> -Icompiler/stage2 -Icompiler/../libraries/base/cbits
>> -Icompiler/../libraries/base/include -Icompiler/. -Icompiler/parser
>> -Icompiler/utils -optP-DGHCI -optP-include
>> -optPcompiler/stage2/build/autogen/cabal_macros.h -package
>> Cabal-1.11.2 -package array- -package base- -package
>> bin-package-db- -package bytestring- -package
>> containers- -package directory- -package
>> filepath- -package hoopl- -package hpc- -package
>> old-time- -package process- -package
>> template-haskell- -package unix- -Wall
>> -fno-warn-name-shadowing -fno-warn-orphans -XHaskell98
>> -XNondecreasingIndentation -XCPP -XMagicHash -XUnboxedTuples
>> -XPatternGuards -XForeignFunctionInterface -XEmptyDataDecls
>> -XTypeSynonymInstances -XMultiParamTypeClasses -XFlexibleInstances
>> -XRank2Types -XScopedTypeVariables
>> -XDeriveDataTypeable-DGHCI_TABLES_NEXT_TO_CODE -DSTAGE=2 -O0 -fasm
>> -no-user-package-conf -rtsopts -odir compiler/stage2/build -hidir
>> compiler/stage2/build -stubdir compiler/stage2/build -hisuf hi -osuf o
>> -hcsuf hc -c compiler/iface/BinIface.hs -o
>> compiler/stage2/build/BinIface.o
>> ghc-stage1: panic! (the 'impossible' happened)
>> (GHC version 7.3.20111007 for x86_64-unknown-linux):
>> applyTypeToArgs
>> ghc-prim:GHC.Prim.sizeofMutableArray#{(w) v 91V} [gid[PrimOp]]
>> @ e{tv i4L2} [tv] ds{v i4Lc} [lid] i#{v i4Lg} [lid]
>> forall a{tv 12} [tv].
>> ghc-prim:GHC.Prim.MutableArray#{(w) tc 31m}
>> e{tv i4L2} [tv] a{tv 12} [tv]
>> -> ghc-prim:GHC.Prim.Int#{(w) tc 3G}
>> Paul Monday
>> Parallel Scientific, LLC.
>> paul.monday at <mailto:paul.monday at>
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