diff options
| -rw-r--r-- | compiler/GHC/Builtin/Names.hs | 13 | ||||
| -rw-r--r-- | compiler/GHC/Types/Name.hs | 60 |
2 files changed, 60 insertions, 13 deletions
diff --git a/compiler/GHC/Builtin/Names.hs b/compiler/GHC/Builtin/Names.hs index 563ccbf57e..40af981264 100644 --- a/compiler/GHC/Builtin/Names.hs +++ b/compiler/GHC/Builtin/Names.hs @@ -1701,13 +1701,18 @@ fingerprintDataConName = All these are original names; hence mkOrig -} +{-# INLINE varQual #-} +{-# INLINE tcQual #-} +{-# INLINE clsQual #-} +{-# INLINE dcQual #-} varQual, tcQual, clsQual, dcQual :: Module -> FastString -> Unique -> Name -varQual = mk_known_key_name varName -tcQual = mk_known_key_name tcName -clsQual = mk_known_key_name clsName -dcQual = mk_known_key_name dataName +varQual modu str unique = mk_known_key_name varName modu str unique +tcQual modu str unique = mk_known_key_name tcName modu str unique +clsQual modu str unique = mk_known_key_name clsName modu str unique +dcQual modu str unique = mk_known_key_name dataName modu str unique mk_known_key_name :: NameSpace -> Module -> FastString -> Unique -> Name +{-# INLINE mk_known_key_name #-} mk_known_key_name space modu str unique = mkExternalName unique modu (mkOccNameFS space str) noSrcSpan diff --git a/compiler/GHC/Types/Name.hs b/compiler/GHC/Types/Name.hs index 0b834cbe2b..c2b76b1bfd 100644 --- a/compiler/GHC/Types/Name.hs +++ b/compiler/GHC/Types/Name.hs @@ -109,16 +109,26 @@ import Data.Data -- | A unique, unambiguous name for something, containing information about where -- that thing originated. -data Name = Name { - n_sort :: NameSort, -- What sort of name it is - n_occ :: !OccName, -- Its occurrence name - n_uniq :: {-# UNPACK #-} !Unique, - n_loc :: !SrcSpan -- Definition site - } +data Name = Name + { n_sort :: NameSort + -- ^ What sort of name it is --- NOTE: we make the n_loc field strict to eliminate some potential --- (and real!) space leaks, due to the fact that we don't look at --- the SrcLoc in a Name all that often. + , n_occ :: OccName + -- ^ Its occurrence name. + -- + -- NOTE: kept lazy to allow known names to be known constructor applications + -- and to inline better. See Note [Fast comparison for built-in Names] + + , n_uniq :: {-# UNPACK #-} !Unique + -- ^ Its unique. + + , n_loc :: !SrcSpan + -- ^ Definition site + -- + -- NOTE: we make the n_loc field strict to eliminate some potential + -- (and real!) space leaks, due to the fact that we don't look at + -- the SrcLoc in a Name all that often. + } -- See Note [About the NameSorts] data NameSort @@ -157,6 +167,36 @@ instance NFData NameSort where data BuiltInSyntax = BuiltInSyntax | UserSyntax {- +Note [Fast comparison for built-in Names] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Consider this wired-in Name in GHC.Builtin.Names: + + int8TyConName = tcQual gHC_INT (fsLit "Int8") int8TyConKey + +Ultimately this turns into something like: + + int8TyConName = Name gHC_INT (mkOccName ..."Int8") int8TyConKey + +So a comparison like `x == int8TyConName` will turn into `getUnique x == +int8TyConKey`, nice and efficient. But if the `n_occ` field is strict, that +definition will look like: + + int8TyCOnName = case (mkOccName..."Int8") of occ -> + Name gHC_INT occ int8TyConKey + +and now the comparison will not optimise. This matters even more when there are +numerous comparisons (see #19386): + +if | tc == int8TyCon -> ... + | tc == int16TyCon -> ... + ...etc... + +when we would like to get a single multi-branched case. + +TL;DR: we make the `n_occ` field lazy. +-} + +{- Note [About the NameSorts] 1. Initially, top-level Ids (including locally-defined ones) get External names, @@ -401,6 +441,7 @@ mkDerivedInternalName derive_occ uniq (Name { n_occ = occ, n_loc = loc }) -- | Create a name which definitely originates in the given module mkExternalName :: Unique -> Module -> OccName -> SrcSpan -> Name +{-# INLINE mkExternalName #-} -- WATCH OUT! External Names should be in the Name Cache -- (see Note [The Name Cache] in GHC.Iface.Env), so don't just call mkExternalName -- with some fresh unique without populating the Name Cache @@ -410,6 +451,7 @@ mkExternalName uniq mod occ loc -- | Create a name which is actually defined by the compiler itself mkWiredInName :: Module -> OccName -> Unique -> TyThing -> BuiltInSyntax -> Name +{-# INLINE mkWiredInName #-} mkWiredInName mod occ uniq thing built_in = Name { n_uniq = uniq, n_sort = WiredIn mod thing built_in, |