{-# OPTIONS -optc-DNON_POSIX_SOURCE #-}
-module PrelRules ( primOpRules, builtinRules ) where
+module PrelRules (
+ primOpRules, builtinRules,
+
+ -- Error Ids defined here because may be called here
+ mkRuntimeErrorApp, mkImpossibleExpr,
+ rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID, rUNTIME_ERROR_ID,
+ nON_EXHAUSTIVE_GUARDS_ERROR_ID, nO_METHOD_BINDING_ERROR_ID,
+ pAT_ERROR_ID, eRROR_ID, rEC_SEL_ERROR_ID,
+ ) where
#include "HsVersions.h"
import CoreSyn
-import Id ( mkWildId, idUnfolding )
-import Literal ( Literal(..), mkMachInt, mkMachWord
- , literalType
- , word2IntLit, int2WordLit
- , narrow8IntLit, narrow16IntLit, narrow32IntLit
- , narrow8WordLit, narrow16WordLit, narrow32WordLit
- , char2IntLit, int2CharLit
- , float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit
- , float2DoubleLit, double2FloatLit, litFitsInChar
- )
+import MkCore ( mkWildCase )
+import Id
+import IdInfo
+import Demand
+import Literal
import PrimOp ( PrimOp(..), tagToEnumKey )
-import TysWiredIn ( boolTy, trueDataConId, falseDataConId )
+import TysWiredIn
+import TysPrim
import TyCon ( tyConDataCons_maybe, isEnumerationTyCon, isNewTyCon )
import DataCon ( dataConTag, dataConTyCon, dataConWorkId, fIRST_TAG )
-import CoreUtils ( cheapEqExpr, exprIsConApp_maybe )
-import Type ( tyConAppTyCon, coreEqType )
+import CoreUtils ( cheapEqExpr )
+import CoreUnfold ( exprIsConApp_maybe )
+import TcType ( mkSigmaTy )
+import Type
import OccName ( occNameFS )
-import PrelNames ( unpackCStringFoldrName, unpackCStringFoldrIdKey, hasKey,
- eqStringName, unpackCStringIdKey, inlineIdName )
+import PrelNames
import Maybes ( orElse )
import Name ( Name, nameOccName )
import Outputable
import FastString
import StaticFlags ( opt_SimplExcessPrecision )
+import Constants
+
import Data.Bits as Bits
import Data.Word ( Word )
\end{code}
floatOp2Z :: (Rational -> Rational -> Rational) -> Literal -> Literal
-> Maybe (Expr CoreBndr)
floatOp2Z op (MachFloat f1) (MachFloat f2)
- | f2 /= 0 = Just (mkFloatVal (f1 `op` f2))
+ | (f1 /= 0 || f2 > 0) -- see Note [negative zero]
+ && f2 /= 0 -- avoid NaN and Infinity/-Infinity
+ = Just (mkFloatVal (f1 `op` f2))
floatOp2Z _ _ _ = Nothing
--------------------------
doubleOp2Z :: (Rational -> Rational -> Rational) -> Literal -> Literal
-> Maybe (Expr CoreBndr)
doubleOp2Z op (MachDouble f1) (MachDouble f2)
- | f2 /= 0 = Just (mkDoubleVal (f1 `op` f2))
+ | (f1 /= 0 || f2 > 0) -- see Note [negative zero]
+ && f2 /= 0 -- avoid NaN and Infinity/-Infinity
+ = Just (mkDoubleVal (f1 `op` f2))
+ -- Note [negative zero] Avoid (0 / -d), otherwise 0/(-1) reduces to
+ -- zero, but we might want to preserve the negative zero here which
+ -- is representable in Float/Double but not in (normalised)
+ -- Rational. (#3676) Perhaps we should generate (0 :% (-1)) instead?
doubleOp2Z _ _ _ = Nothing
ru_fn = op_name,
ru_nargs = 2, ru_try = rule_fn }]
where
- rule_fn [Lit lit, expr] = do_lit_eq lit expr
- rule_fn [expr, Lit lit] = do_lit_eq lit expr
- rule_fn _ = Nothing
+ rule_fn _ [Lit lit, expr] = do_lit_eq lit expr
+ rule_fn _ [expr, Lit lit] = do_lit_eq lit expr
+ rule_fn _ _ = Nothing
do_lit_eq lit expr
- = Just (Case expr (mkWildId (literalType lit)) boolTy
+ = Just (mkWildCase expr (literalType lit) boolTy
[(DEFAULT, [], val_if_neq),
(LitAlt lit, [], val_if_eq)])
val_if_eq | is_eq = trueVal
-- runtime either, and compilation of completely harmless things like
-- ((124076834 :: Word32) + (2147483647 :: Word32))
-- would yield a warning. Instead we simply squash the value into the
--- Int range, but not in a way suitable for cross-compiling... :-(
+-- *target* Int/Word range.
intResult :: Integer -> Maybe CoreExpr
intResult result
- = Just (mkIntVal (toInteger (fromInteger result :: Int)))
+ = Just (mkIntVal (toInteger (fromInteger result :: TargetInt)))
wordResult :: Integer -> Maybe CoreExpr
wordResult result
- = Just (mkWordVal (toInteger (fromInteger result :: Word)))
+ = Just (mkWordVal (toInteger (fromInteger result :: TargetWord)))
\end{code}
%************************************************************************
\begin{code}
-mkBasicRule :: Name -> Int -> ([CoreExpr] -> Maybe CoreExpr) -> [CoreRule]
+mkBasicRule :: Name -> Int
+ -> (IdUnfoldingFun -> [CoreExpr] -> Maybe CoreExpr)
+ -> [CoreRule]
-- Gives the Rule the same name as the primop itself
mkBasicRule op_name n_args rule_fn
= [BuiltinRule { ru_name = occNameFS (nameOccName op_name),
oneLit op_name test
= mkBasicRule op_name 1 rule_fn
where
- rule_fn [Lit l1] = test (convFloating l1)
- rule_fn _ = Nothing
+ rule_fn _ [Lit l1] = test (convFloating l1)
+ rule_fn _ _ = Nothing
twoLits :: Name -> (Literal -> Literal -> Maybe CoreExpr)
-> [CoreRule]
twoLits op_name test
= mkBasicRule op_name 2 rule_fn
where
- rule_fn [Lit l1, Lit l2] = test (convFloating l1) (convFloating l2)
- rule_fn _ = Nothing
+ rule_fn _ [Lit l1, Lit l2] = test (convFloating l1) (convFloating l2)
+ rule_fn _ _ = Nothing
-- When excess precision is not requested, cut down the precision of the
-- Rational value to that of Float/Double. We confuse host architecture
%* *
%************************************************************************
+Note [tagToEnum#]
+~~~~~~~~~~~~~~~~~
+Nasty check to ensure that tagToEnum# is applied to a type that is an
+enumeration TyCon. Unification may refine the type later, but this
+check won't see that, alas. It's crude but it works.
+
+Here's are two cases that should fail
+ f :: forall a. a
+ f = tagToEnum# 0 -- Can't do tagToEnum# at a type variable
+
+ g :: Int
+ g = tagToEnum# 0 -- Int is not an enumeration
+
+We used to make this check in the type inference engine, but it's quite
+ugly to do so, because the delayed constraint solving means that we don't
+really know what's going on until the end. It's very much a corner case
+because we don't expect the user to call tagToEnum# at all; we merely
+generate calls in derived instances of Enum. So we compromise: a
+rewrite rule rewrites a bad instance of tagToEnum# to an error call,
+and emits a warning.
+
\begin{code}
-tagToEnumRule :: [Expr CoreBndr] -> Maybe (Expr CoreBndr)
-tagToEnumRule [Type ty, Lit (MachInt i)]
+tagToEnumRule :: IdUnfoldingFun -> [Expr CoreBndr] -> Maybe (Expr CoreBndr)
+tagToEnumRule _ [Type ty, _]
+ | not (is_enum_ty ty) -- See Note [tagToEnum#]
+ = WARN( True, ptext (sLit "tagToEnum# on non-enumeration type") <+> ppr ty )
+ Just (mkRuntimeErrorApp rUNTIME_ERROR_ID ty "tagToEnum# on non-enumeration type")
+ where
+ is_enum_ty ty = case splitTyConApp_maybe ty of
+ Just (tc, _) -> isEnumerationTyCon tc
+ Nothing -> False
+
+tagToEnumRule _ [Type ty, Lit (MachInt i)]
= ASSERT( isEnumerationTyCon tycon )
case filter correct_tag (tyConDataCons_maybe tycon `orElse` []) of
-
-
[] -> Nothing -- Abstract type
(dc:rest) -> ASSERT( null rest )
Just (Var (dataConWorkId dc))
tag = fromInteger i
tycon = tyConAppTyCon ty
-tagToEnumRule _ = Nothing
+tagToEnumRule _ _ = Nothing
\end{code}
+
For dataToTag#, we can reduce if either
(a) the argument is a constructor
(b) the argument is a variable whose unfolding is a known constructor
\begin{code}
-dataToTagRule :: [Expr CoreBndr] -> Maybe (Arg CoreBndr)
-dataToTagRule [Type ty1, Var tag_to_enum `App` Type ty2 `App` tag]
+dataToTagRule :: IdUnfoldingFun -> [Expr CoreBndr] -> Maybe (Arg CoreBndr)
+dataToTagRule _ [Type ty1, Var tag_to_enum `App` Type ty2 `App` tag]
| tag_to_enum `hasKey` tagToEnumKey
, ty1 `coreEqType` ty2
= Just tag -- dataToTag (tagToEnum x) ==> x
-dataToTagRule [_, val_arg]
- | Just (dc,_) <- exprIsConApp_maybe val_arg
+dataToTagRule id_unf [_, val_arg]
+ | Just (dc,_,_) <- exprIsConApp_maybe id_unf val_arg
= ASSERT( not (isNewTyCon (dataConTyCon dc)) )
Just (mkIntVal (toInteger (dataConTag dc - fIRST_TAG)))
-dataToTagRule _ = Nothing
+dataToTagRule _ _ = Nothing
\end{code}
%************************************************************************
---------------------------------------------------
-- The rule is this:
--- unpackFoldrCString# "foo" c (unpackFoldrCString# "baz" c n) = unpackFoldrCString# "foobaz" c n
-
-match_append_lit :: [Expr CoreBndr] -> Maybe (Expr CoreBndr)
-match_append_lit [Type ty1,
- Lit (MachStr s1),
- c1,
- Var unpk `App` Type ty2
- `App` Lit (MachStr s2)
- `App` c2
- `App` n
- ]
+-- unpackFoldrCString# "foo" c (unpackFoldrCString# "baz" c n)
+-- = unpackFoldrCString# "foobaz" c n
+
+match_append_lit :: IdUnfoldingFun -> [Expr CoreBndr] -> Maybe (Expr CoreBndr)
+match_append_lit _ [Type ty1,
+ Lit (MachStr s1),
+ c1,
+ Var unpk `App` Type ty2
+ `App` Lit (MachStr s2)
+ `App` c2
+ `App` n
+ ]
| unpk `hasKey` unpackCStringFoldrIdKey &&
c1 `cheapEqExpr` c2
= ASSERT( ty1 `coreEqType` ty2 )
`App` c1
`App` n)
-match_append_lit _ = Nothing
+match_append_lit _ _ = Nothing
---------------------------------------------------
-- The rule is this:
-- eqString (unpackCString# (Lit s1)) (unpackCString# (Lit s2) = s1==s2
-match_eq_string :: [Expr CoreBndr] -> Maybe (Expr CoreBndr)
-match_eq_string [Var unpk1 `App` Lit (MachStr s1),
- Var unpk2 `App` Lit (MachStr s2)]
+match_eq_string :: IdUnfoldingFun -> [Expr CoreBndr] -> Maybe (Expr CoreBndr)
+match_eq_string _ [Var unpk1 `App` Lit (MachStr s1),
+ Var unpk2 `App` Lit (MachStr s2)]
| unpk1 `hasKey` unpackCStringIdKey,
unpk2 `hasKey` unpackCStringIdKey
= Just (if s1 == s2 then trueVal else falseVal)
-match_eq_string _ = Nothing
+match_eq_string _ _ = Nothing
---------------------------------------------------
-- The rule is this:
-- inline f_ty (f a b c) = <f's unfolding> a b c
--- (if f has an unfolding)
+-- (if f has an unfolding, EVEN if it's a loop breaker)
--
-- It's important to allow the argument to 'inline' to have args itself
-- (a) because its more forgiving to allow the programmer to write
-- programmer can't avoid
--
-- Also, don't forget about 'inline's type argument!
-match_inline :: [Expr CoreBndr] -> Maybe (Expr CoreBndr)
-match_inline (Type _ : e : _)
+match_inline :: IdUnfoldingFun -> [Expr CoreBndr] -> Maybe (Expr CoreBndr)
+match_inline _ (Type _ : e : _)
| (Var f, args1) <- collectArgs e,
- Just unf <- maybeUnfoldingTemplate (idUnfolding f)
+ Just unf <- maybeUnfoldingTemplate (realIdUnfolding f)
+ -- Ignore the IdUnfoldingFun here!
= Just (mkApps unf args1)
-match_inline _ = Nothing
-\end{code}
+match_inline _ _ = Nothing
+\end{code}
+
+%************************************************************************
+%* *
+\subsection[PrelVals-error-related]{@error@ and friends; @trace@}
+%* *
+%************************************************************************
+b
+GHC randomly injects these into the code.
+
+@patError@ is just a version of @error@ for pattern-matching
+failures. It knows various ``codes'' which expand to longer
+strings---this saves space!
+
+@absentErr@ is a thing we put in for ``absent'' arguments. They jolly
+well shouldn't be yanked on, but if one is, then you will get a
+friendly message from @absentErr@ (rather than a totally random
+crash).
+
+@parError@ is a special version of @error@ which the compiler does
+not know to be a bottoming Id. It is used in the @_par_@ and @_seq_@
+templates, but we don't ever expect to generate code for it.
+
+\begin{code}
+mkRuntimeErrorApp
+ :: Id -- Should be of type (forall a. Addr# -> a)
+ -- where Addr# points to a UTF8 encoded string
+ -> Type -- The type to instantiate 'a'
+ -> String -- The string to print
+ -> CoreExpr
+
+mkRuntimeErrorApp err_id res_ty err_msg
+ = mkApps (Var err_id) [Type res_ty, err_string]
+ where
+ err_string = Lit (mkMachString err_msg)
+
+mkImpossibleExpr :: Type -> CoreExpr
+mkImpossibleExpr res_ty
+ = mkRuntimeErrorApp rUNTIME_ERROR_ID res_ty "Impossible case alternative"
+
+errorName, recSelErrorName, runtimeErrorName :: Name
+irrefutPatErrorName, recConErrorName, patErrorName :: Name
+nonExhaustiveGuardsErrorName, noMethodBindingErrorName :: Name
+errorName = mkWiredInIdName gHC_ERR (fsLit "error") errorIdKey eRROR_ID
+recSelErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "recSelError") recSelErrorIdKey rEC_SEL_ERROR_ID
+runtimeErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "runtimeError") runtimeErrorIdKey rUNTIME_ERROR_ID
+irrefutPatErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "irrefutPatError") irrefutPatErrorIdKey iRREFUT_PAT_ERROR_ID
+recConErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "recConError") recConErrorIdKey rEC_CON_ERROR_ID
+patErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "patError") patErrorIdKey pAT_ERROR_ID
+noMethodBindingErrorName = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "noMethodBindingError")
+ noMethodBindingErrorIdKey nO_METHOD_BINDING_ERROR_ID
+nonExhaustiveGuardsErrorName
+ = mkWiredInIdName cONTROL_EXCEPTION_BASE (fsLit "nonExhaustiveGuardsError")
+ nonExhaustiveGuardsErrorIdKey nON_EXHAUSTIVE_GUARDS_ERROR_ID
+
+rEC_SEL_ERROR_ID, rUNTIME_ERROR_ID, iRREFUT_PAT_ERROR_ID, rEC_CON_ERROR_ID :: Id
+pAT_ERROR_ID, nO_METHOD_BINDING_ERROR_ID, nON_EXHAUSTIVE_GUARDS_ERROR_ID :: Id
+rEC_SEL_ERROR_ID = mkRuntimeErrorId recSelErrorName
+rUNTIME_ERROR_ID = mkRuntimeErrorId runtimeErrorName
+iRREFUT_PAT_ERROR_ID = mkRuntimeErrorId irrefutPatErrorName
+rEC_CON_ERROR_ID = mkRuntimeErrorId recConErrorName
+pAT_ERROR_ID = mkRuntimeErrorId patErrorName
+nO_METHOD_BINDING_ERROR_ID = mkRuntimeErrorId noMethodBindingErrorName
+nON_EXHAUSTIVE_GUARDS_ERROR_ID = mkRuntimeErrorId nonExhaustiveGuardsErrorName
+
+-- The runtime error Ids take a UTF8-encoded string as argument
+
+mkRuntimeErrorId :: Name -> Id
+mkRuntimeErrorId name = pc_bottoming_Id name runtimeErrorTy
+
+runtimeErrorTy :: Type
+runtimeErrorTy = mkSigmaTy [openAlphaTyVar] [] (mkFunTy addrPrimTy openAlphaTy)
+\end{code}
+
+\begin{code}
+eRROR_ID :: Id
+eRROR_ID = pc_bottoming_Id errorName errorTy
+
+errorTy :: Type
+errorTy = mkSigmaTy [openAlphaTyVar] [] (mkFunTys [mkListTy charTy] openAlphaTy)
+ -- Notice the openAlphaTyVar. It says that "error" can be applied
+ -- to unboxed as well as boxed types. This is OK because it never
+ -- returns, so the return type is irrelevant.
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Utilities}
+%* *
+%************************************************************************
+
+\begin{code}
+pc_bottoming_Id :: Name -> Type -> Id
+-- Function of arity 1, which diverges after being given one argument
+pc_bottoming_Id name ty
+ = mkVanillaGlobalWithInfo name ty bottoming_info
+ where
+ bottoming_info = vanillaIdInfo `setStrictnessInfo` Just strict_sig
+ `setArityInfo` 1
+ -- Make arity and strictness agree
+
+ -- Do *not* mark them as NoCafRefs, because they can indeed have
+ -- CAF refs. For example, pAT_ERROR_ID calls GHC.Err.untangle,
+ -- which has some CAFs
+ -- In due course we may arrange that these error-y things are
+ -- regarded by the GC as permanently live, in which case we
+ -- can give them NoCaf info. As it is, any function that calls
+ -- any pc_bottoming_Id will itself have CafRefs, which bloats
+ -- SRTs.
+
+ strict_sig = mkStrictSig (mkTopDmdType [evalDmd] BotRes)
+ -- These "bottom" out, no matter what their arguments
+\end{code}
+
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