%
-% (c) The AQUA Project, Glasgow University, 1994-1996
+% (c) The AQUA Project, Glasgow University, 1994-1998
%
\section[DsCCall]{Desugaring \tr{_ccall_}s and \tr{_casm_}s}
\begin{code}
-#include "HsVersions.h"
-
-module DsCCall ( dsCCall ) where
+module DsCCall
+ ( dsCCall
+ , mkCCall
+ , unboxArg
+ , boxResult
+ , resultWrapper
+ ) where
-import Ubiq
+#include "HsVersions.h"
import CoreSyn
import DsMonad
import DsUtils
-import CoreUtils ( coreExprType )
-import Id ( dataConArgTys, mkTupleCon )
+import CoreUtils ( exprType, mkCoerce )
+import Id ( Id, mkWildId )
+import MkId ( mkCCallOpId, realWorldPrimId )
import Maybes ( maybeToBool )
-import PprStyle ( PprStyle(..) )
-import PprType ( GenType{-instances-} )
-import PrelInfo ( byteArrayPrimTy, getStatePairingConInfo,
- packStringForCId, realWorldStatePrimTy,
- realWorldStateTy, realWorldTy, stateDataCon,
- stringTy )
-import Pretty
-import PrimOp ( PrimOp(..) )
-import Type ( isPrimType, maybeAppDataTyCon, eqTy )
-import Util ( pprPanic, pprError, panic )
-
-maybeBoxedPrimType = panic "DsCCall.maybeBoxedPrimType"
+import PrimOp ( PrimOp(..), CCall(..), CCallTarget(..) )
+import DataCon ( DataCon, splitProductType_maybe, dataConSourceArity, dataConWrapId )
+import CallConv
+import Type ( isUnLiftedType, splitAlgTyConApp_maybe, mkFunTys,
+ splitTyConApp_maybe, tyVarsOfType, mkForAllTys,
+ isNewType, repType, isUnLiftedType, mkFunTy,
+ Type
+ )
+import TysPrim ( byteArrayPrimTy, realWorldStatePrimTy,
+ byteArrayPrimTyCon, mutableByteArrayPrimTyCon, intPrimTy
+ )
+import TysWiredIn ( unitDataConId, stringTy,
+ unboxedPairDataCon,
+ mkUnboxedTupleTy, unboxedTupleCon,
+ boolTy, trueDataCon, falseDataCon, trueDataConId, falseDataConId,
+ unitTy
+ )
+import Literal ( mkMachInt )
+import CStrings ( CLabelString )
+import Unique ( Unique, Uniquable(..), ioTyConKey )
+import VarSet ( varSetElems )
+import Outputable
\end{code}
Desugaring of @ccall@s consists of adding some state manipulation,
desired.
The state stuff just consists of adding in
-@\ s -> case s of { S# s# -> ... }@ in an appropriate place.
+@PrimIO (\ s -> case s of { S# s# -> ... })@ in an appropriate place.
The unboxing is straightforward, as all information needed to unbox is
available from the type. For each boxed-primitive argument, we
\end{verbatim}
\begin{code}
-dsCCall :: FAST_STRING -- C routine to invoke
+dsCCall :: CLabelString -- C routine to invoke
-> [CoreExpr] -- Arguments (desugared)
- -> Bool -- True <=> might cause Haskell GC
- -> Bool -- True <=> really a "_casm_"
- -> Type -- Type of the result (a boxed-prim type)
+ -> Bool -- True <=> might cause Haskell GC
+ -> Bool -- True <=> really a "_casm_"
+ -> Type -- Type of the result: IO t
-> DsM CoreExpr
-dsCCall label args may_gc is_asm result_ty
- = newSysLocalDs realWorldStateTy `thenDs` \ old_s ->
-
- mapAndUnzipDs unboxArg (Var old_s : args) `thenDs` \ (final_args, arg_wrappers) ->
-
- boxResult result_ty `thenDs` \ (final_result_ty, res_wrapper) ->
-
- let
- the_ccall_op = CCallOp label is_asm may_gc
- (map coreExprType final_args)
- final_result_ty
- in
- mkPrimDs the_ccall_op
- [] -- ***NOTE*** no ty apps; the types are inside the_ccall_op.
- final_args `thenDs` \ the_prim_app ->
+dsCCall lbl args may_gc is_asm result_ty
+ = mapAndUnzipDs unboxArg args `thenDs` \ (unboxed_args, arg_wrappers) ->
+ boxResult result_ty `thenDs` \ (ccall_result_ty, res_wrapper) ->
+ getUniqueDs `thenDs` \ uniq ->
let
- the_body = foldr apply (res_wrapper the_prim_app) arg_wrappers
+ the_ccall = CCall (StaticTarget lbl) is_asm may_gc cCallConv
+ the_prim_app = mkCCall uniq the_ccall unboxed_args ccall_result_ty
in
- returnDs (Lam (ValBinder old_s) the_body)
+ returnDs (foldr ($) (res_wrapper the_prim_app) arg_wrappers)
+
+mkCCall :: Unique -> CCall
+ -> [CoreExpr] -- Args
+ -> Type -- Result type
+ -> CoreExpr
+-- Construct the ccall. The only tricky bit is that the ccall Id should have
+-- no free vars, so if any of the arg tys do we must give it a polymorphic type.
+-- [I forget *why* it should have no free vars!]
+-- For example:
+-- mkCCall ... [s::StablePtr (a->b), x::Addr, c::Char]
+--
+-- Here we build a ccall thus
+-- (ccallid::(forall a b. StablePtr (a -> b) -> Addr -> Char -> IO Addr))
+-- a b s x c
+mkCCall uniq the_ccall val_args res_ty
+ = mkApps (mkVarApps (Var the_ccall_id) tyvars) val_args
where
- apply f x = f x
+ arg_tys = map exprType val_args
+ body_ty = (mkFunTys arg_tys res_ty)
+ tyvars = varSetElems (tyVarsOfType body_ty)
+ ty = mkForAllTys tyvars body_ty
+ the_ccall_id = mkCCallOpId uniq the_ccall ty
\end{code}
\begin{code}
unboxArg :: CoreExpr -- The supplied argument
- -> DsM (CoreExpr, -- To pass as the actual argument
+ -> DsM (CoreExpr, -- To pass as the actual argument
CoreExpr -> CoreExpr -- Wrapper to unbox the arg
)
-unboxArg arg
+-- Example: if the arg is e::Int, unboxArg will return
+-- (x#::Int#, \W. case x of I# x# -> W)
+-- where W is a CoreExpr that probably mentions x#
- -- Primitive types
- -- ADR Question: can this ever be used? None of the PrimTypes are
- -- instances of the CCallable class.
- | isPrimType arg_ty
+unboxArg arg
+ -- Unlifted types: nothing to unbox
+ | isUnLiftedType arg_ty
= returnDs (arg, \body -> body)
- -- Strings
- | arg_ty `eqTy` stringTy
- -- ToDo (ADR): - allow synonyms of Strings too?
- = newSysLocalDs byteArrayPrimTy `thenDs` \ prim_arg ->
- mkAppDs (Var packStringForCId) [] [arg] `thenDs` \ pack_appn ->
+ -- Newtypes
+ | isNewType arg_ty
+ = unboxArg (mkCoerce (repType arg_ty) arg_ty arg)
+
+ -- Booleans
+ | arg_ty == boolTy
+ = newSysLocalDs intPrimTy `thenDs` \ prim_arg ->
returnDs (Var prim_arg,
- \body -> Case pack_appn (PrimAlts []
- (BindDefault prim_arg body))
- )
-
- | null data_cons
- -- oops: we can't see the data constructors!!!
- = can't_see_datacons_error "argument" arg_ty
-
- -- Byte-arrays, both mutable and otherwise
- -- (HACKy method -- but we really don't want the TyCons wired-in...) [WDP 94/10]
- | is_data_type &&
- length data_con_arg_tys == 2 &&
- not (isPrimType data_con_arg_ty1) &&
- isPrimType data_con_arg_ty2
- -- and, of course, it is an instance of CCallable
--- ( tycon == byteArrayTyCon ||
--- tycon == mutableByteArrayTyCon )
- = newSysLocalsDs data_con_arg_tys `thenDs` \ vars@[ixs_var, arr_cts_var] ->
- returnDs (Var arr_cts_var,
- \ body -> Case arg (AlgAlts [(the_data_con,vars,body)]
- NoDefault)
- )
+ \ body -> Case (Case arg (mkWildId arg_ty)
+ [(DataAlt falseDataCon,[],mkIntLit 0),
+ (DataAlt trueDataCon, [],mkIntLit 1)])
+ prim_arg
+ [(DEFAULT,[],body)])
-- Data types with a single constructor, which has a single, primitive-typed arg
- | maybeToBool maybe_boxed_prim_arg_ty
- = newSysLocalDs the_prim_arg_ty `thenDs` \ prim_arg ->
+ -- This deals with Int, Float etc
+ | is_product_type && data_con_arity == 1
+ = ASSERT(isUnLiftedType data_con_arg_ty1 ) -- Typechecker ensures this
+ newSysLocalDs arg_ty `thenDs` \ case_bndr ->
+ newSysLocalDs data_con_arg_ty1 `thenDs` \ prim_arg ->
returnDs (Var prim_arg,
- \ body -> Case arg (AlgAlts [(box_data_con,[prim_arg],body)]
- NoDefault)
+ \ body -> Case arg case_bndr [(DataAlt data_con,[prim_arg],body)]
)
- -- ... continued below ....
-\end{code}
-
-As an experiment, I'm going to unpack any "acceptably small"
-enumeration. This code will never get used in the main version
-because enumerations would have triggered type errors but I've
-disabled type-checking in my version. ADR
-
-To Will: It might be worth leaving this in (but commented out) until
-we decide what's happening with enumerations. ADR
-
-\begin{code}
-#if 0
- -- MAYBE LATER:
- -- Data types with a nullary constructors (enumeration)
- | isEnumerationType arg_ty && -- enumeration
- (length data_cons) <= 5 -- "acceptably short"
- = newSysLocalDs the_prim_arg_ty `thenDs` \ prim_arg ->
-
- let
- alts = [ (con, [], mkMachInt i) | (con,i) <- data_cons `zip` [0..] ]
- arg_tag = Case arg (AlgAlts alts) NoDefault
- in
- returnDs (Var prim_arg,
- \ body -> Case arg_tag (PrimAlts [(prim_arg, body)] NoDefault)
+ -- Byte-arrays, both mutable and otherwise; hack warning
+ | is_product_type &&
+ data_con_arity == 3 &&
+ maybeToBool maybe_arg3_tycon &&
+ (arg3_tycon == byteArrayPrimTyCon ||
+ arg3_tycon == mutableByteArrayPrimTyCon)
+ -- and, of course, it is an instance of CCallable
+ = newSysLocalDs arg_ty `thenDs` \ case_bndr ->
+ newSysLocalsDs data_con_arg_tys `thenDs` \ vars@[l_var, r_var, arr_cts_var] ->
+ returnDs (Var arr_cts_var,
+ \ body -> Case arg case_bndr [(DataAlt data_con,vars,body)]
)
-#endif
-\end{code}
-\begin{code}
- -- ... continued from above ....
| otherwise
- = pprPanic "unboxArg: " (ppr PprDebug arg_ty)
+ = getSrcLocDs `thenDs` \ l ->
+ pprPanic "unboxArg: " (ppr l <+> ppr arg_ty)
where
- arg_ty = coreExprType arg
-
- maybe_boxed_prim_arg_ty = maybeBoxedPrimType arg_ty
- (Just (box_data_con, the_prim_arg_ty)) = maybe_boxed_prim_arg_ty
-
- maybe_data_type = maybeAppDataTyCon arg_ty
- is_data_type = maybeToBool maybe_data_type
- (Just (tycon, tycon_arg_tys, data_cons)) = maybe_data_type
- (the_data_con : other_data_cons) = data_cons
-
- data_con_arg_tys = dataConArgTys the_data_con tycon_arg_tys
- (data_con_arg_ty1 : data_con_arg_ty2 : _) = data_con_arg_tys
-
-can't_see_datacons_error thing ty
- = pprError "ERROR: Can't see the data constructor(s) for _ccall_/_casm_ "
- (ppBesides [ppStr thing, ppStr "; type: ", ppr PprForUser ty])
+ arg_ty = exprType arg
+ arg_rep_ty = repType arg_ty
+
+ maybe_product_type = splitProductType_maybe arg_ty
+ is_product_type = maybeToBool maybe_product_type
+ Just (tycon, _, data_con, data_con_arg_tys) = maybe_product_type
+ data_con_arity = dataConSourceArity data_con
+ (data_con_arg_ty1 : _) = data_con_arg_tys
+
+ (_ : _ : data_con_arg_ty3 : _) = data_con_arg_tys
+ maybe_arg3_tycon = splitTyConApp_maybe data_con_arg_ty3
+ Just (arg3_tycon,_) = maybe_arg3_tycon
\end{code}
\begin{code}
-tuple_con_2 = mkTupleCon 2 -- out here to avoid CAF (sigh)
-covar_tuple_con_0 = Var (mkTupleCon 0) -- ditto
+boxResult :: Type -> DsM (Type, CoreExpr -> CoreExpr)
+
+-- Takes the result of the user-level ccall:
+-- either (IO t),
+-- or maybe just t for an side-effect-free call
+-- Returns a wrapper for the primitive ccall itself, along with the
+-- type of the result of the primitive ccall. This result type
+-- will be of the form
+-- State# RealWorld -> (# State# RealWorld, t' #)
+-- where t' is the unwrapped form of t. If t is simply (), then
+-- the result type will be
+-- State# RealWorld -> (# State# RealWorld #)
-boxResult :: Type -- Type of desired result
- -> DsM (Type, -- Type of the result of the ccall itself
- CoreExpr -> CoreExpr) -- Wrapper for the ccall
- -- to box the result
boxResult result_ty
- | null data_cons
- -- oops! can't see the data constructors
- = can't_see_datacons_error "result" result_ty
-
- -- Data types with a single constructor, which has a single, primitive-typed arg
- | (maybeToBool maybe_data_type) && -- Data type
- (null other_data_cons) && -- Just one constr
- not (null data_con_arg_tys) && null other_args_tys && -- Just one arg
- isPrimType the_prim_result_ty -- of primitive type
- =
- newSysLocalDs realWorldStatePrimTy `thenDs` \ prim_state_id ->
- newSysLocalDs the_prim_result_ty `thenDs` \ prim_result_id ->
-
- mkConDs stateDataCon [realWorldTy] [Var prim_state_id] `thenDs` \ new_state ->
- mkConDs the_data_con tycon_arg_tys [Var prim_result_id] `thenDs` \ the_result ->
-
- mkConDs tuple_con_2
- [result_ty, realWorldStateTy]
- [the_result, new_state] `thenDs` \ the_pair ->
- let
- the_alt = (state_and_prim_datacon, [prim_state_id, prim_result_id], the_pair)
- in
- returnDs (state_and_prim_ty,
- \prim_app -> Case prim_app (AlgAlts [the_alt] NoDefault)
- )
-
- -- Data types with a single nullary constructor
- | (maybeToBool maybe_data_type) && -- Data type
- (null other_data_cons) && -- Just one constr
- (null data_con_arg_tys)
- =
- newSysLocalDs realWorldStatePrimTy `thenDs` \ prim_state_id ->
-
- mkConDs stateDataCon [realWorldTy] [Var prim_state_id] `thenDs` \ new_state ->
-
- mkConDs tuple_con_2
- [result_ty, realWorldStateTy]
- [covar_tuple_con_0, new_state] `thenDs` \ the_pair ->
-
- let
- the_alt = (stateDataCon, [prim_state_id], the_pair)
- in
- returnDs (realWorldStateTy,
- \prim_app -> Case prim_app (AlgAlts [the_alt] NoDefault)
- )
-
-#if 0
- -- MAYBE LATER???
-
- -- Data types with several nullary constructors (Enumerated types)
- | isEnumerationType result_ty && -- Enumeration
- (length data_cons) <= 5 -- fairly short
- =
- newSysLocalDs realWorldStatePrimTy `thenDs` \ prim_state_id ->
- newSysLocalDs intPrimTy `thenDs` \ prim_result_id ->
-
- mkConDs stateDataCon [realWorldTy] [Var prim_state_id] `thenDs` \ new_state ->
-
- let
- alts = [ (mkMachInt i, con) | (i, con) <- [0..] `zip` data_cons ]
- the_result = Case prim_result_id (PrimAlts alts) NoDefault
+ = case splitAlgTyConApp_maybe result_ty of
+
+ -- The result is IO t, so wrap the result in an IO constructor
+ Just (io_tycon, [io_res_ty], [io_data_con]) | getUnique io_tycon == ioTyConKey
+ -> mk_alt return_result
+ (resultWrapper io_res_ty) `thenDs` \ (ccall_res_ty, the_alt) ->
+ newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id ->
+ let
+ wrap = \ the_call -> mkApps (Var (dataConWrapId io_data_con))
+ [Type io_res_ty, Lam state_id $
+ Case (App the_call (Var state_id))
+ (mkWildId ccall_res_ty)
+ [the_alt]]
+ in
+ returnDs (realWorldStatePrimTy `mkFunTy` ccall_res_ty, wrap)
+ where
+ return_result state ans = mkConApp unboxedPairDataCon
+ [Type realWorldStatePrimTy, Type io_res_ty,
+ state, ans]
+
+ -- It isn't, so do unsafePerformIO
+ -- It's not conveniently available, so we inline it
+ other -> mk_alt return_result
+ (resultWrapper result_ty) `thenDs` \ (ccall_res_ty, the_alt) ->
+ let
+ wrap = \ the_call -> Case (App the_call (Var realWorldPrimId))
+ (mkWildId ccall_res_ty)
+ [the_alt]
+ in
+ returnDs (realWorldStatePrimTy `mkFunTy` ccall_res_ty, wrap)
+ where
+ return_result state ans = ans
+ where
+ mk_alt return_result (Nothing, wrap_result)
+ = -- The ccall returns ()
+ newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id ->
+ let
+ the_rhs = return_result (Var state_id) (wrap_result (panic "boxResult"))
+ ccall_res_ty = mkUnboxedTupleTy 1 [realWorldStatePrimTy]
+ the_alt = (DataAlt (unboxedTupleCon 1), [state_id], the_rhs)
+ in
+ returnDs (ccall_res_ty, the_alt)
+
+ mk_alt return_result (Just prim_res_ty, wrap_result)
+ = -- The ccall returns a non-() value
+ newSysLocalDs realWorldStatePrimTy `thenDs` \ state_id ->
+ newSysLocalDs prim_res_ty `thenDs` \ result_id ->
+ let
+ the_rhs = return_result (Var state_id) (wrap_result (Var result_id))
+ ccall_res_ty = mkUnboxedTupleTy 2 [realWorldStatePrimTy, prim_res_ty]
+ the_alt = (DataAlt unboxedPairDataCon, [state_id, result_id], the_rhs)
+ in
+ returnDs (ccall_res_ty, the_alt)
+
+
+resultWrapper :: Type
+ -> (Maybe Type, -- Type of the expected result, if any
+ CoreExpr -> CoreExpr) -- Wrapper for the result
+resultWrapper result_ty
+ -- Base case 1: primitive types
+ | isUnLiftedType result_ty
+ = (Just result_ty, \e -> e)
+
+ -- Base case 1: the unit type ()
+ | result_ty == unitTy
+ = (Nothing, \e -> Var unitDataConId)
+
+ | result_ty == boolTy
+ = (Just intPrimTy, \e -> Case e (mkWildId intPrimTy)
+ [(LitAlt (mkMachInt 0),[],Var falseDataConId),
+ (DEFAULT ,[],Var trueDataConId )])
+
+ -- Data types with a single constructor, which has a single arg
+ | is_product_type && data_con_arity == 1
+ = let
+ (maybe_ty, wrapper) = resultWrapper unwrapped_res_ty
+ (unwrapped_res_ty : _) = data_con_arg_tys
in
-
- mkConDs (mkTupleCon 2)
- [result_ty, realWorldStateTy]
- [the_result, new_state] `thenDs` \ the_pair ->
- let
- the_alt = (state_and_prim_datacon, [prim_state_id, prim_result_id], the_pair)
+ (maybe_ty, \e -> mkApps (Var (dataConWrapId data_con))
+ (map Type tycon_arg_tys ++ [wrapper e]))
+
+ -- newtypes
+ | isNewType result_ty
+ = let
+ rep_ty = repType result_ty
+ (maybe_ty, wrapper) = resultWrapper rep_ty
in
- returnDs (state_and_prim_ty,
- \prim_app -> Case prim_app (AlgAlts [the_alt] NoDefault)
- )
-#endif
+ (maybe_ty, \e -> mkCoerce result_ty rep_ty (wrapper e))
| otherwise
- = pprPanic "boxResult: " (ppr PprDebug result_ty)
-
+ = pprPanic "resultWrapper" (ppr result_ty)
where
- maybe_data_type = maybeAppDataTyCon result_ty
- Just (tycon, tycon_arg_tys, data_cons) = maybe_data_type
- (the_data_con : other_data_cons) = data_cons
-
- data_con_arg_tys = dataConArgTys the_data_con tycon_arg_tys
- (the_prim_result_ty : other_args_tys) = data_con_arg_tys
-
- (state_and_prim_datacon, state_and_prim_ty) = getStatePairingConInfo the_prim_result_ty
+ maybe_product_type = splitProductType_maybe result_ty
+ is_product_type = maybeToBool maybe_product_type
+ Just (tycon, tycon_arg_tys, data_con, data_con_arg_tys) = maybe_product_type
+ data_con_arity = dataConSourceArity data_con
\end{code}
-
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