{-# LANGUAGE CPP #-} -- | This is where we define a mapping from Uniques to their associated -- known-key Names for things associated with tuples and sums. We use this -- mapping while deserializing known-key Names in interface file symbol tables, -- which are encoded as their Unique. See Note [Symbol table representation of -- names] for details. -- module GHC.Builtin.Uniques ( -- * Looking up known-key names knownUniqueName -- * Getting the 'Unique's of 'Name's -- ** Anonymous sums , mkSumTyConUnique , mkSumDataConUnique -- ** Tuples -- *** Vanilla , mkTupleTyConUnique , mkTupleDataConUnique -- *** Constraint , mkCTupleTyConUnique , mkCTupleDataConUnique , mkCTupleSelIdUnique -- ** Making built-in uniques , mkAlphaTyVarUnique , mkPrimOpIdUnique, mkPrimOpWrapperUnique , mkPreludeMiscIdUnique, mkPreludeDataConUnique , mkPreludeTyConUnique, mkPreludeClassUnique , mkCoVarUnique , mkVarOccUnique, mkDataOccUnique, mkTvOccUnique, mkTcOccUnique , mkRegSingleUnique, mkRegPairUnique, mkRegClassUnique, mkRegSubUnique , mkCostCentreUnique , mkBuiltinUnique , mkPseudoUniqueD , mkPseudoUniqueE , mkPseudoUniqueH -- ** Deriving uniquesc -- *** From TyCon name uniques , tyConRepNameUnique -- *** From DataCon name uniques , dataConWorkerUnique, dataConTyRepNameUnique , initTyVarUnique , initExitJoinUnique ) where #include "GhclibHsVersions.h" import GHC.Prelude import {-# SOURCE #-} GHC.Builtin.Types import {-# SOURCE #-} GHC.Core.TyCon import {-# SOURCE #-} GHC.Core.DataCon import {-# SOURCE #-} GHC.Types.Id import {-# SOURCE #-} GHC.Types.Name import GHC.Types.Basic import GHC.Types.Unique import GHC.Data.FastString import GHC.Utils.Outputable import GHC.Utils.Misc import GHC.Utils.Panic import Data.Maybe -- | Get the 'Name' associated with a known-key 'Unique'. knownUniqueName :: Unique -> Maybe Name knownUniqueName u = case tag of 'z' -> Just $ getUnboxedSumName n '4' -> Just $ getTupleTyConName Boxed n '5' -> Just $ getTupleTyConName Unboxed n '7' -> Just $ getTupleDataConName Boxed n '8' -> Just $ getTupleDataConName Unboxed n 'j' -> Just $ getCTupleSelIdName n 'k' -> Just $ getCTupleTyConName n 'm' -> Just $ getCTupleDataConName n _ -> Nothing where (tag, n) = unpkUnique u {- Note [Unique layout for unboxed sums] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Sum arities start from 2. The encoding is a bit funny: we break up the integral part into bitfields for the arity, an alternative index (which is taken to be 0xfc in the case of the TyCon), and, in the case of a datacon, a tag (used to identify the sum's TypeRep binding). This layout is chosen to remain compatible with the usual unique allocation for wired-in data constructors described in GHC.Types.Unique TyCon for sum of arity k: 00000000 kkkkkkkk 11111100 TypeRep of TyCon for sum of arity k: 00000000 kkkkkkkk 11111101 DataCon for sum of arity k and alternative n (zero-based): 00000000 kkkkkkkk nnnnnn00 TypeRep for sum DataCon of arity k and alternative n (zero-based): 00000000 kkkkkkkk nnnnnn10 -} mkSumTyConUnique :: Arity -> Unique mkSumTyConUnique arity = ASSERT(arity < 0x3f) -- 0x3f since we only have 6 bits to encode the -- alternative mkUnique 'z' (arity `shiftL` 8 .|. 0xfc) mkSumDataConUnique :: ConTagZ -> Arity -> Unique mkSumDataConUnique alt arity | alt >= arity = panic ("mkSumDataConUnique: " ++ show alt ++ " >= " ++ show arity) | otherwise = mkUnique 'z' (arity `shiftL` 8 + alt `shiftL` 2) {- skip the tycon -} getUnboxedSumName :: Int -> Name getUnboxedSumName n | n .&. 0xfc == 0xfc = case tag of 0x0 -> tyConName $ sumTyCon arity 0x1 -> getRep $ sumTyCon arity _ -> pprPanic "getUnboxedSumName: invalid tag" (ppr tag) | tag == 0x0 = dataConName $ sumDataCon (alt + 1) arity | tag == 0x1 = getName $ dataConWrapId $ sumDataCon (alt + 1) arity | tag == 0x2 = getRep $ promoteDataCon $ sumDataCon (alt + 1) arity | otherwise = pprPanic "getUnboxedSumName" (ppr n) where arity = n `shiftR` 8 alt = (n .&. 0xfc) `shiftR` 2 tag = 0x3 .&. n getRep tycon = fromMaybe (pprPanic "getUnboxedSumName(getRep)" (ppr tycon)) $ tyConRepName_maybe tycon -- Note [Uniques for tuple type and data constructors] -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- -- Wired-in type constructor keys occupy *two* slots: -- * u: the TyCon itself -- * u+1: the TyConRepName of the TyCon -- -- Wired-in tuple data constructor keys occupy *three* slots: -- * u: the DataCon itself -- * u+1: its worker Id -- * u+2: the TyConRepName of the promoted TyCon {- Note [Unique layout for constraint tuple selectors] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Constraint tuples, like boxed and unboxed tuples, have their type and data constructor Uniques wired in (see Note [Uniques for tuple type and data constructors]). Constraint tuples are somewhat more involved, however. For a boxed or unboxed n-tuple, we need: * A Unique for the type constructor, and * A Unique for the data constructor With a constraint n-tuple, however, we need: * A Unique for the type constructor, * A Unique for the data constructor, and * A Unique for each of the n superclass selectors To pick a concrete example (n = 2), the binary constraint tuple has a type constructor and data constructor (%,%) along with superclass selectors $p1(%,%) and $p2(%,%). Just as we wire in the Uniques for constraint tuple type constructors and data constructors, we wish to wire in the Uniques for the superclass selectors as well. Not only does this make everything consistent, it also avoids a compile-time performance penalty whenever GHC.Classes is loaded from an interface file. This is because GHC.Classes defines constraint tuples as class definitions, and if these classes weren't wired in, then loading GHC.Classes would also load every single constraint tuple type constructor, data constructor, and superclass selector. See #18635. We encode the Uniques for constraint tuple superclass selectors as follows. The integral part of the Unique is broken up into bitfields for the arity and the position of the superclass. Given a selector for a constraint tuple with arity n (zero-based) and position k (where 1 <= k <= n), its Unique will look like: 00000000 nnnnnnnn kkkkkkkk We can use bit-twiddling tricks to access the arity and position with cTupleSelIdArityBits and cTupleSelIdPosBitmask, respectively. This pattern bears a certain resemblance to the way that the Uniques for unboxed sums are encoded. This is because for a unboxed sum of arity n, there are n corresponding data constructors, each with an alternative position k. Similarly, for a constraint tuple of arity n, there are n corresponding superclass selectors. Reading Note [Unique layout for unboxed sums] will instill an appreciation for how the encoding for constraint tuple superclass selector Uniques takes inspiration from the encoding for unboxed sum Uniques. -} mkCTupleTyConUnique :: Arity -> Unique mkCTupleTyConUnique a = mkUnique 'k' (2*a) mkCTupleDataConUnique :: Arity -> Unique mkCTupleDataConUnique a = mkUnique 'm' (3*a) mkCTupleSelIdUnique :: ConTagZ -> Arity -> Unique mkCTupleSelIdUnique sc_pos arity | sc_pos >= arity = panic ("mkCTupleSelIdUnique: " ++ show sc_pos ++ " >= " ++ show arity) | otherwise = mkUnique 'j' (arity `shiftL` cTupleSelIdArityBits + sc_pos) getCTupleTyConName :: Int -> Name getCTupleTyConName n = case n `divMod` 2 of (arity, 0) -> cTupleTyConName arity (arity, 1) -> mkPrelTyConRepName $ cTupleTyConName arity _ -> panic "getCTupleTyConName: impossible" getCTupleDataConName :: Int -> Name getCTupleDataConName n = case n `divMod` 3 of (arity, 0) -> cTupleDataConName arity (arity, 1) -> getName $ dataConWrapId $ cTupleDataCon arity (arity, 2) -> mkPrelTyConRepName $ cTupleDataConName arity _ -> panic "getCTupleDataConName: impossible" getCTupleSelIdName :: Int -> Name getCTupleSelIdName n = cTupleSelIdName (sc_pos + 1) arity where arity = n `shiftR` cTupleSelIdArityBits sc_pos = n .&. cTupleSelIdPosBitmask -- Given the arity of a constraint tuple, this is the number of bits by which -- one must shift it to the left in order to encode the arity in the Unique -- of a superclass selector for that constraint tuple. Alternatively, given the -- Unique for a constraint tuple superclass selector, this is the number of -- bits by which one must shift it to the right to retrieve the arity of the -- constraint tuple. See Note [Unique layout for constraint tuple selectors]. cTupleSelIdArityBits :: Int cTupleSelIdArityBits = 8 -- Given the Unique for a constraint tuple superclass selector, one can -- retrieve the position of the selector by ANDing this mask, which will -- clear all but the eight least significant bits. -- See Note [Unique layout for constraint tuple selectors]. cTupleSelIdPosBitmask :: Int cTupleSelIdPosBitmask = 0xff -------------------------------------------------- -- Normal tuples mkTupleDataConUnique :: Boxity -> Arity -> Unique mkTupleDataConUnique Boxed a = mkUnique '7' (3*a) -- may be used in C labels mkTupleDataConUnique Unboxed a = mkUnique '8' (3*a) mkTupleTyConUnique :: Boxity -> Arity -> Unique mkTupleTyConUnique Boxed a = mkUnique '4' (2*a) mkTupleTyConUnique Unboxed a = mkUnique '5' (2*a) getTupleTyConName :: Boxity -> Int -> Name getTupleTyConName boxity n = case n `divMod` 2 of (arity, 0) -> tyConName $ tupleTyCon boxity arity (arity, 1) -> fromMaybe (panic "getTupleTyConName") $ tyConRepName_maybe $ tupleTyCon boxity arity _ -> panic "getTupleTyConName: impossible" getTupleDataConName :: Boxity -> Int -> Name getTupleDataConName boxity n = case n `divMod` 3 of (arity, 0) -> dataConName $ tupleDataCon boxity arity (arity, 1) -> idName $ dataConWorkId $ tupleDataCon boxity arity (arity, 2) -> fromMaybe (panic "getTupleDataCon") $ tyConRepName_maybe $ promotedTupleDataCon boxity arity _ -> panic "getTupleDataConName: impossible" {- Note [Uniques for wired-in prelude things and known masks] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Allocation of unique supply characters: v,t,u : for renumbering value-, type- and usage- vars. B: builtin C-E: pseudo uniques (used in native-code generator) I: GHCi evaluation X: uniques from mkLocalUnique _: unifiable tyvars (above) 0-9: prelude things below (no numbers left any more..) :: (prelude) parallel array data constructors other a-z: lower case chars for unique supplies. Used so far: a TypeChecking? c StgToCmm/Renamer d desugarer f AbsC flattener g SimplStg i TypeChecking interface files j constraint tuple superclass selectors k constraint tuple tycons m constraint tuple datacons n Native/LLVM codegen r Hsc name cache s simplifier u Cmm pipeline y GHCi bytecode generator z anonymous sums -} mkAlphaTyVarUnique :: Int -> Unique mkPreludeClassUnique :: Int -> Unique mkPrimOpIdUnique :: Int -> Unique -- See Note [Primop wrappers] in GHC.Builtin.PrimOps. mkPrimOpWrapperUnique :: Int -> Unique mkPreludeMiscIdUnique :: Int -> Unique mkCoVarUnique :: Int -> Unique mkAlphaTyVarUnique i = mkUnique '1' i mkCoVarUnique i = mkUnique 'g' i mkPreludeClassUnique i = mkUnique '2' i -------------------------------------------------- mkPrimOpIdUnique op = mkUnique '9' (2*op) mkPrimOpWrapperUnique op = mkUnique '9' (2*op+1) mkPreludeMiscIdUnique i = mkUnique '0' i -- The "tyvar uniques" print specially nicely: a, b, c, etc. -- See pprUnique for details initTyVarUnique :: Unique initTyVarUnique = mkUnique 't' 0 mkPseudoUniqueD, mkPseudoUniqueE, mkPseudoUniqueH, mkBuiltinUnique :: Int -> Unique mkBuiltinUnique i = mkUnique 'B' i mkPseudoUniqueD i = mkUnique 'D' i -- used in NCG for getUnique on RealRegs mkPseudoUniqueE i = mkUnique 'E' i -- used in NCG spiller to create spill VirtualRegs mkPseudoUniqueH i = mkUnique 'H' i -- used in NCG spiller to create spill VirtualRegs mkRegSingleUnique, mkRegPairUnique, mkRegSubUnique, mkRegClassUnique :: Int -> Unique mkRegSingleUnique = mkUnique 'R' mkRegSubUnique = mkUnique 'S' mkRegPairUnique = mkUnique 'P' mkRegClassUnique = mkUnique 'L' mkCostCentreUnique :: Int -> Unique mkCostCentreUnique = mkUnique 'C' mkVarOccUnique, mkDataOccUnique, mkTvOccUnique, mkTcOccUnique :: FastString -> Unique -- See Note [The Unique of an OccName] in GHC.Types.Name.Occurrence mkVarOccUnique fs = mkUnique 'i' (uniqueOfFS fs) mkDataOccUnique fs = mkUnique 'd' (uniqueOfFS fs) mkTvOccUnique fs = mkUnique 'v' (uniqueOfFS fs) mkTcOccUnique fs = mkUnique 'c' (uniqueOfFS fs) initExitJoinUnique :: Unique initExitJoinUnique = mkUnique 's' 0 -------------------------------------------------- -- Wired-in type constructor keys occupy *two* slots: -- * u: the TyCon itself -- * u+1: the TyConRepName of the TyCon mkPreludeTyConUnique :: Int -> Unique mkPreludeTyConUnique i = mkUnique '3' (2*i) tyConRepNameUnique :: Unique -> Unique tyConRepNameUnique u = incrUnique u -------------------------------------------------- -- Wired-in data constructor keys occupy *three* slots: -- * u: the DataCon itself -- * u+1: its worker Id -- * u+2: the TyConRepName of the promoted TyCon -- Prelude data constructors are too simple to need wrappers. mkPreludeDataConUnique :: Arity -> Unique mkPreludeDataConUnique i = mkUnique '6' (3*i) -- Must be alphabetic -------------------------------------------------- dataConTyRepNameUnique, dataConWorkerUnique :: Unique -> Unique dataConWorkerUnique u = incrUnique u dataConTyRepNameUnique u = stepUnique u 2