2 % (c) The University of Glasgow 2000
4 \section[ByteCodeGen]{Generate bytecode from Core}
7 module ByteCodeGen ( UnlinkedBCO, UnlinkedBCOExpr, ItblEnv, ClosureEnv, HValue,
9 byteCodeGen, coreExprToBCOs
12 #include "HsVersions.h"
15 import Name ( Name, getName )
16 import Id ( Id, idType, isDataConId_maybe, isPrimOpId_maybe, isFCallId,
17 idPrimRep, mkSysLocal, idName, isFCallId_maybe )
18 import ForeignCall ( ForeignCall(..), CCallTarget(..), CCallSpec(..) )
19 import OrdList ( OrdList, consOL, snocOL, appOL, unitOL,
20 nilOL, toOL, concatOL, fromOL )
21 import FiniteMap ( FiniteMap, addListToFM, listToFM, elemFM,
22 addToFM, lookupFM, fmToList )
24 import PprCore ( pprCoreExpr )
25 import Literal ( Literal(..), literalPrimRep )
26 import PrimRep ( PrimRep(..) )
27 import PrimOp ( PrimOp(..) )
28 import CoreFVs ( freeVars )
29 import Type ( typePrimRep, splitTyConApp_maybe, isTyVarTy )
30 import DataCon ( dataConTag, fIRST_TAG, dataConTyCon,
31 dataConWrapId, isUnboxedTupleCon )
32 import TyCon ( TyCon(..), tyConFamilySize, isDataTyCon, tyConDataCons,
33 isFunTyCon, isUnboxedTupleTyCon )
34 import Class ( Class, classTyCon )
35 import Type ( Type, repType, splitRepFunTys )
36 import Util ( zipEqual, zipWith4Equal, naturalMergeSortLe, nOfThem,
37 isSingleton, lengthIs )
38 import DataCon ( dataConRepArity )
39 import Var ( isTyVar )
40 import VarSet ( VarSet, varSetElems )
41 import PrimRep ( isFollowableRep )
42 import CmdLineOpts ( DynFlags, DynFlag(..) )
43 import ErrUtils ( showPass, dumpIfSet_dyn )
44 import Unique ( mkPseudoUnique3 )
45 import FastString ( FastString(..) )
46 import Panic ( GhcException(..) )
47 import PprType ( pprType )
48 import SMRep ( arrWordsHdrSize, arrPtrsHdrSize )
49 import Constants ( wORD_SIZE )
50 import ByteCodeInstr ( BCInstr(..), ProtoBCO(..), nameOfProtoBCO, bciStackUse )
51 import ByteCodeItbls ( ItblEnv, mkITbls )
52 import ByteCodeLink ( UnlinkedBCO, UnlinkedBCOExpr, assembleBCO,
53 ClosureEnv, HValue, filterNameMap, linkFail,
54 iNTERP_STACK_CHECK_THRESH )
55 import ByteCodeFFI ( taggedSizeW, untaggedSizeW, mkMarshalCode, moan64 )
56 import Linker ( lookupSymbol )
58 import List ( intersperse, sortBy, zip4 )
59 import Foreign ( Ptr(..), mallocBytes )
60 import Addr ( Addr(..), writeCharOffAddr )
61 import CTypes ( CInt )
62 import Exception ( throwDyn )
64 import PrelBase ( Int(..) )
65 import PrelGHC ( ByteArray# )
66 import PrelIOBase ( IO(..) )
68 import Maybe ( isJust )
71 %************************************************************************
73 \subsection{Functions visible from outside this module.}
75 %************************************************************************
79 byteCodeGen :: DynFlags
82 -> IO ([UnlinkedBCO], ItblEnv)
83 byteCodeGen dflags binds local_tycons local_classes
84 = do showPass dflags "ByteCodeGen"
85 let tycs = local_tycons ++ map classTyCon local_classes
86 itblenv <- mkITbls tycs
88 let flatBinds = concatMap getBind binds
89 getBind (NonRec bndr rhs) = [(bndr, freeVars rhs)]
90 getBind (Rec binds) = [(bndr, freeVars rhs) | (bndr,rhs) <- binds]
92 (BcM_State proto_bcos final_ctr mallocd, ())
93 <- runBc (BcM_State [] 0 [])
94 (mapBc (schemeR True []) flatBinds `thenBc_` returnBc ())
96 -- better be no free vars in these top-level bindings
98 when (not (null mallocd))
99 (panic "ByteCodeGen.byteCodeGen: missing final emitBc?")
101 dumpIfSet_dyn dflags Opt_D_dump_BCOs
102 "Proto-bcos" (vcat (intersperse (char ' ') (map ppr proto_bcos)))
104 bcos <- mapM assembleBCO proto_bcos
106 return (bcos, itblenv)
109 -- Returns: (the root BCO for this expression,
110 -- a list of auxilary BCOs resulting from compiling closures)
111 coreExprToBCOs :: DynFlags
113 -> IO UnlinkedBCOExpr
114 coreExprToBCOs dflags expr
115 = do showPass dflags "ByteCodeGen"
117 -- create a totally bogus name for the top-level BCO; this
118 -- should be harmless, since it's never used for anything
119 let invented_id = mkSysLocal SLIT("Expr-Top-Level") (mkPseudoUnique3 0)
120 (panic "invented_id's type")
121 let invented_name = idName invented_id
123 annexpr = freeVars expr
124 fvs = filter (not.isTyVar) (varSetElems (fst annexpr))
126 (BcM_State all_proto_bcos final_ctr mallocd, ())
127 <- runBc (BcM_State [] 0 [])
128 (schemeR True fvs (invented_id, annexpr))
130 when (not (null mallocd))
131 (panic "ByteCodeGen.coreExprToBCOs: missing final emitBc?")
133 dumpIfSet_dyn dflags Opt_D_dump_BCOs
134 "Proto-bcos" (vcat (intersperse (char ' ') (map ppr all_proto_bcos)))
137 = case filter ((== invented_name).nameOfProtoBCO) all_proto_bcos of
138 [root_bco] -> root_bco
140 = filter ((/= invented_name).nameOfProtoBCO) all_proto_bcos
142 auxiliary_bcos <- mapM assembleBCO auxiliary_proto_bcos
143 root_bco <- assembleBCO root_proto_bco
145 return (root_bco, auxiliary_bcos)
148 %************************************************************************
150 \subsection{Compilation schema for the bytecode generator.}
152 %************************************************************************
156 type BCInstrList = OrdList BCInstr
158 type Sequel = Int -- back off to this depth before ENTER
160 -- Maps Ids to the offset from the stack _base_ so we don't have
161 -- to mess with it after each push/pop.
162 type BCEnv = FiniteMap Id Int -- To find vars on the stack
164 ppBCEnv :: BCEnv -> SDoc
167 $$ nest 4 (vcat (map pp_one (sortBy cmp_snd (fmToList p))))
170 pp_one (var, offset) = int offset <> colon <+> ppr var
171 cmp_snd x y = compare (snd x) (snd y)
173 -- Create a BCO and do a spot of peephole optimisation on the insns
175 mkProtoBCO nm instrs_ordlist origin mallocd_blocks
176 = ProtoBCO nm maybe_with_stack_check origin mallocd_blocks
178 -- Overestimate the stack usage (in words) of this BCO,
179 -- and if >= iNTERP_STACK_CHECK_THRESH, add an explicit
180 -- stack check. (The interpreter always does a stack check
181 -- for iNTERP_STACK_CHECK_THRESH words at the start of each
182 -- BCO anyway, so we only need to add an explicit on in the
183 -- (hopefully rare) cases when the (overestimated) stack use
184 -- exceeds iNTERP_STACK_CHECK_THRESH.
185 maybe_with_stack_check
186 | stack_overest >= 65535
187 = pprPanic "mkProtoBCO: stack use won't fit in 16 bits"
189 | stack_overest >= iNTERP_STACK_CHECK_THRESH
190 = (STKCHECK stack_overest) : peep_d
192 = peep_d -- the supposedly common case
194 stack_overest = sum (map bciStackUse peep_d)
195 + 10 {- just to be really really sure -}
198 -- Merge local pushes
199 peep_d = peep (fromOL instrs_ordlist)
201 peep (PUSH_L off1 : PUSH_L off2 : PUSH_L off3 : rest)
202 = PUSH_LLL off1 (off2-1) (off3-2) : peep rest
203 peep (PUSH_L off1 : PUSH_L off2 : rest)
204 = PUSH_LL off1 (off2-1) : peep rest
211 -- Compile code for the right hand side of a let binding.
212 -- Park the resulting BCO in the monad. Also requires the
213 -- variable to which this value was bound, so as to give the
214 -- resulting BCO a name. Bool indicates top-levelness.
216 schemeR :: Bool -> [Id] -> (Id, AnnExpr Id VarSet) -> BcM ()
217 schemeR is_top fvs (nm, rhs)
221 $$ (ppr.filter (not.isTyVar).varSetElems.fst) rhs
222 $$ pprCoreExpr (deAnnotate rhs)
228 = schemeR_wrk is_top fvs rhs nm (collect [] rhs)
231 collect xs (_, AnnNote note e)
233 collect xs (_, AnnLam x e)
234 = collect (if isTyVar x then xs else (x:xs)) e
235 collect xs not_lambda
236 = (reverse xs, not_lambda)
238 schemeR_wrk is_top fvs original_body nm (args, body)
239 | Just dcon <- maybe_toplevel_null_con_rhs
240 = --trace ("nullary constructor! " ++ showSDocDebug (ppr nm)) (
241 emitBc (mkProtoBCO (getName nm) (toOL [PACK dcon 0, ENTER])
242 (Right original_body))
246 = let all_args = reverse args ++ fvs
247 szsw_args = map taggedIdSizeW all_args
248 szw_args = sum szsw_args
249 p_init = listToFM (zip all_args (mkStackOffsets 0 szsw_args))
250 argcheck = unitOL (ARGCHECK szw_args)
252 schemeE szw_args 0 p_init body `thenBc` \ body_code ->
253 emitBc (mkProtoBCO (getName nm) (appOL argcheck body_code)
254 (Right original_body))
257 maybe_toplevel_null_con_rhs
258 | is_top && null args
259 = case nukeTyArgs (snd body) of
261 -> case isDataConId_maybe v_wrk of
263 Just dc_wrk | nm == dataConWrapId dc_wrk
271 nukeTyArgs (AnnApp f (_, AnnType _)) = nukeTyArgs (snd f)
272 nukeTyArgs other = other
275 -- Let szsw be the sizes in words of some items pushed onto the stack,
276 -- which has initial depth d'. Return the values which the stack environment
277 -- should map these items to.
278 mkStackOffsets :: Int -> [Int] -> [Int]
279 mkStackOffsets original_depth szsw
280 = map (subtract 1) (tail (scanl (+) original_depth szsw))
282 -- Compile code to apply the given expression to the remaining args
283 -- on the stack, returning a HNF.
284 schemeE :: Int -> Sequel -> BCEnv -> AnnExpr Id VarSet -> BcM BCInstrList
286 -- Delegate tail-calls to schemeT.
287 schemeE d s p e@(fvs, AnnApp f a)
288 = schemeT d s p (fvs, AnnApp f a)
290 schemeE d s p e@(fvs, AnnVar v)
291 | isFollowableRep v_rep
292 = -- Ptr-ish thing; push it in the normal way
293 schemeT d s p (fvs, AnnVar v)
296 = -- returning an unboxed value. Heave it on the stack, SLIDE, and RETURN.
297 pushAtom True d p (AnnVar v) `thenBc` \ (push, szw) ->
298 returnBc (push -- value onto stack
299 `appOL` mkSLIDE szw (d-s) -- clear to sequel
300 `snocOL` RETURN v_rep) -- go
302 v_rep = typePrimRep (idType v)
304 schemeE d s p (fvs, AnnLit literal)
305 = pushAtom True d p (AnnLit literal) `thenBc` \ (push, szw) ->
306 let l_rep = literalPrimRep literal
307 in returnBc (push -- value onto stack
308 `appOL` mkSLIDE szw (d-s) -- clear to sequel
309 `snocOL` RETURN l_rep) -- go
311 schemeE d s p (fvs, AnnLet binds b)
312 = let (xs,rhss) = case binds of AnnNonRec x rhs -> ([x],[rhs])
313 AnnRec xs_n_rhss -> unzip xs_n_rhss
316 is_local id = not (isTyVar id) && elemFM id p'
317 fvss = map (filter is_local . varSetElems . fst) rhss
319 -- Sizes of tagged free vars, + 1 for the fn
320 sizes = map (\rhs_fvs -> 1 + sum (map taggedIdSizeW rhs_fvs)) fvss
322 -- This p', d' defn is safe because all the items being pushed
323 -- are ptrs, so all have size 1. d' and p' reflect the stack
324 -- after the closures have been allocated in the heap (but not
325 -- filled in), and pointers to them parked on the stack.
326 p' = addListToFM p (zipE xs (mkStackOffsets d (nOfThem n 1)))
329 infos = zipE4 fvss sizes xs [n, n-1 .. 1]
330 zipE = zipEqual "schemeE"
331 zipE4 = zipWith4Equal "schemeE" (\a b c d -> (a,b,c,d))
333 -- ToDo: don't build thunks for things with no free variables
334 buildThunk dd ([], size, id, off)
335 = returnBc (PUSH_G (Left (getName id))
336 `consOL` unitOL (MKAP (off+size-1) size))
337 buildThunk dd ((fv:fvs), size, id, off)
338 = pushAtom True dd p' (AnnVar fv)
339 `thenBc` \ (push_code, pushed_szw) ->
340 buildThunk (dd+pushed_szw) (fvs, size, id, off)
341 `thenBc` \ more_push_code ->
342 returnBc (push_code `appOL` more_push_code)
344 genThunkCode = mapBc (buildThunk d') infos `thenBc` \ tcodes ->
345 returnBc (concatOL tcodes)
347 allocCode = toOL (map ALLOC sizes)
349 schemeRs [] _ _ = returnBc ()
350 schemeRs (fvs:fvss) (x:xs) (rhs:rhss) =
351 schemeR False fvs (x,rhs) `thenBc_` schemeRs fvss xs rhss
353 schemeE d' s p' b `thenBc` \ bodyCode ->
354 schemeRs fvss xs rhss `thenBc_`
355 genThunkCode `thenBc` \ thunkCode ->
356 returnBc (allocCode `appOL` thunkCode `appOL` bodyCode)
362 schemeE d s p (fvs_case, AnnCase (fvs_scrut, scrut) bndr
363 [(DEFAULT, [], (fvs_rhs, rhs))])
365 | let isFunType var_type
366 = case splitTyConApp_maybe var_type of
367 Just (tycon,_) | isFunTyCon tycon -> True
369 ty_bndr = repType (idType bndr)
370 in isFunType ty_bndr || isTyVarTy ty_bndr
373 -- case scrut::suspect of bndr { DEFAULT -> rhs }
375 -- let bndr = scrut in rhs
376 -- when suspect is polymorphic or arrowtyped
377 -- So the required strictness properties are not observed.
378 -- At some point, must fix this properly.
382 (AnnNonRec bndr (fvs_scrut, scrut)) (fvs_rhs, rhs)
385 in trace ("WARNING: ignoring polymorphic case in interpreted mode.\n" ++
386 " Possibly due to strict polymorphic/functional constructor args.\n" ++
387 " Your program may leak space unexpectedly.\n")
388 (schemeE d s p new_expr)
392 {- Convert case .... of (# VoidRep'd-thing, a #) -> ...
394 case .... of a -> ...
395 Use a as the name of the binder too.
397 Also case .... of (# a #) -> ...
399 case .... of a -> ...
401 schemeE d s p (fvs, AnnCase scrut bndr [(DataAlt dc, [bind1, bind2], rhs)])
402 | isUnboxedTupleCon dc && VoidRep == typePrimRep (idType bind1)
403 = --trace "automagic mashing of case alts (# VoidRep, a #)" (
404 schemeE d s p (fvs, AnnCase scrut bind2 [(DEFAULT, [bind2], rhs)])
407 schemeE d s p (fvs, AnnCase scrut bndr [(DataAlt dc, [bind1], rhs)])
408 | isUnboxedTupleCon dc
409 = --trace "automagic mashing of case alts (# a #)" (
410 schemeE d s p (fvs, AnnCase scrut bind1 [(DEFAULT, [bind1], rhs)])
413 schemeE d s p (fvs, AnnCase scrut bndr alts)
415 -- Top of stack is the return itbl, as usual.
416 -- underneath it is the pointer to the alt_code BCO.
417 -- When an alt is entered, it assumes the returned value is
418 -- on top of the itbl.
421 -- Env and depth in which to compile the alts, not including
422 -- any vars bound by the alts themselves
423 d' = d + ret_frame_sizeW + taggedIdSizeW bndr
424 p' = addToFM p bndr (d' - 1)
426 scrut_primrep = typePrimRep (idType bndr)
428 | scrut_primrep == PtrRep
430 | scrut_primrep `elem`
431 [CharRep, AddrRep, WordRep, IntRep, FloatRep, DoubleRep,
432 VoidRep, Int8Rep, Int16Rep, Int32Rep, Int64Rep,
433 Word8Rep, Word16Rep, Word32Rep, Word64Rep]
436 = pprPanic "ByteCodeGen.schemeE" (ppr scrut_primrep)
438 -- given an alt, return a discr and code for it.
439 codeAlt alt@(discr, binds_f, rhs)
441 = let (unpack_code, d_after_unpack, p_after_unpack)
442 = mkUnpackCode (filter (not.isTyVar) binds_f) d' p'
443 in schemeE d_after_unpack s p_after_unpack rhs
444 `thenBc` \ rhs_code ->
445 returnBc (my_discr alt, unpack_code `appOL` rhs_code)
447 = ASSERT(null binds_f)
448 schemeE d' s p' rhs `thenBc` \ rhs_code ->
449 returnBc (my_discr alt, rhs_code)
451 my_discr (DEFAULT, binds, rhs) = NoDiscr
452 my_discr (DataAlt dc, binds, rhs)
453 | isUnboxedTupleCon dc
454 = unboxedTupleException
456 = DiscrP (dataConTag dc - fIRST_TAG)
457 my_discr (LitAlt l, binds, rhs)
458 = case l of MachInt i -> DiscrI (fromInteger i)
459 MachFloat r -> DiscrF (fromRational r)
460 MachDouble r -> DiscrD (fromRational r)
461 MachChar i -> DiscrI i
462 _ -> pprPanic "schemeE(AnnCase).my_discr" (ppr l)
465 | not isAlgCase = Nothing
467 = case [dc | (DataAlt dc, _, _) <- alts] of
469 (dc:_) -> Just (tyConFamilySize (dataConTyCon dc))
472 mapBc codeAlt alts `thenBc` \ alt_stuff ->
473 mkMultiBranch maybe_ncons alt_stuff `thenBc` \ alt_final ->
475 alt_final_ac = ARGCHECK (taggedIdSizeW bndr) `consOL` alt_final
476 alt_bco_name = getName bndr
477 alt_bco = mkProtoBCO alt_bco_name alt_final_ac (Left alts)
479 schemeE (d + ret_frame_sizeW)
480 (d + ret_frame_sizeW) p scrut `thenBc` \ scrut_code ->
482 emitBc alt_bco `thenBc_`
483 returnBc (PUSH_AS alt_bco_name scrut_primrep `consOL` scrut_code)
486 schemeE d s p (fvs, AnnNote note body)
490 = pprPanic "ByteCodeGen.schemeE: unhandled case"
491 (pprCoreExpr (deAnnotate other))
494 -- Compile code to do a tail call. Specifically, push the fn,
495 -- slide the on-stack app back down to the sequel depth,
496 -- and enter. Four cases:
499 -- An application "PrelGHC.tagToEnum# <type> unboxed-int".
500 -- The int will be on the stack. Generate a code sequence
501 -- to convert it to the relevant constructor, SLIDE and ENTER.
503 -- 1. A nullary constructor. Push its closure on the stack
504 -- and SLIDE and RETURN.
506 -- 2. (Another nasty hack). Spot (# a::VoidRep, b #) and treat
507 -- it simply as b -- since the representations are identical
508 -- (the VoidRep takes up zero stack space). Also, spot
509 -- (# b #) and treat it as b.
511 -- 3. The fn denotes a ccall. Defer to generateCCall.
513 -- 4. Application of a non-nullary constructor, by defn saturated.
514 -- Split the args into ptrs and non-ptrs, and push the nonptrs,
515 -- then the ptrs, and then do PACK and RETURN.
517 -- 5. Otherwise, it must be a function call. Push the args
518 -- right to left, SLIDE and ENTER.
520 schemeT :: Int -- Stack depth
521 -> Sequel -- Sequel depth
522 -> BCEnv -- stack env
528 -- | trace ("schemeT: env in = \n" ++ showSDocDebug (ppBCEnv p)) False
529 -- = panic "schemeT ?!?!"
531 -- | trace ("\nschemeT\n" ++ showSDoc (pprCoreExpr (deAnnotate app)) ++ "\n") False
535 | Just (arg, constr_names) <- maybe_is_tagToEnum_call
536 = pushAtom True d p arg `thenBc` \ (push, arg_words) ->
537 implement_tagToId constr_names `thenBc` \ tagToId_sequence ->
538 returnBc (push `appOL` tagToId_sequence
539 `appOL` mkSLIDE 1 (d+arg_words-s)
543 | is_con_call && null args_r_to_l
545 (PUSH_G (Left (getName con)) `consOL` mkSLIDE 1 (d-s))
550 | let isVoidRepAtom (_, AnnVar v) = VoidRep == typePrimRep (idType v)
551 isVoidRepAtom (_, AnnNote n e) = isVoidRepAtom e
552 in is_con_call && isUnboxedTupleCon con
553 && ( (args_r_to_l `lengthIs` 2 && isVoidRepAtom (last (args_r_to_l)))
554 || (isSingleton args_r_to_l)
556 = --trace (if isSingleton args_r_to_l
557 -- then "schemeT: unboxed singleton"
558 -- else "schemeT: unboxed pair with Void first component") (
559 schemeT d s p (head args_r_to_l)
563 | Just (CCall ccall_spec) <- isFCallId_maybe fn
564 = generateCCall d s p ccall_spec fn args_r_to_l
568 = if is_con_call && isUnboxedTupleCon con
569 then unboxedTupleException
570 else do_pushery d (map snd args_final_r_to_l)
573 -- Detect and extract relevant info for the tagToEnum kludge.
574 maybe_is_tagToEnum_call
575 = let extract_constr_Names ty
576 = case splitTyConApp_maybe (repType ty) of
577 (Just (tyc, [])) | isDataTyCon tyc
578 -> map getName (tyConDataCons tyc)
579 other -> panic "maybe_is_tagToEnum_call.extract_constr_Ids"
582 (_, AnnApp (_, AnnApp (_, AnnVar v) (_, AnnType t)) arg)
583 -> case isPrimOpId_maybe v of
584 Just TagToEnumOp -> Just (snd arg, extract_constr_Names t)
588 -- Extract the args (R->L) and fn
589 (args_r_to_l, fn) = chomp app
594 | isTypeAtom (snd a) -> chomp f
595 | otherwise -> case chomp f of (az, f) -> (a:az, f)
596 AnnNote n e -> chomp e
597 other -> pprPanic "schemeT"
598 (ppr (deAnnotate (panic "schemeT.chomp", other)))
600 n_args = length args_r_to_l
602 isTypeAtom (AnnType _) = True
605 -- decide if this is a constructor application, because we need
606 -- to rearrange the arguments on the stack if so. For building
607 -- a constructor, we put pointers before non-pointers and omit
610 -- Also if the constructor is not saturated, we just arrange to
611 -- call the curried worker instead.
613 maybe_dcon = case isDataConId_maybe fn of
614 Just con | dataConRepArity con == n_args -> Just con
616 is_con_call = isJust maybe_dcon
617 (Just con) = maybe_dcon
623 = filter (not.isPtr.snd) args_r_to_l ++ filter (isPtr.snd) args_r_to_l
624 where isPtr = isFollowableRep . atomRep
626 -- make code to push the args and then do the SLIDE-ENTER thing
627 tag_when_push = not is_con_call
628 narg_words = sum (map (get_arg_szw . atomRep . snd) args_r_to_l)
629 get_arg_szw = if tag_when_push then taggedSizeW else untaggedSizeW
631 do_pushery d (arg:args)
632 = pushAtom tag_when_push d p arg `thenBc` \ (push, arg_words) ->
633 do_pushery (d+arg_words) args `thenBc` \ more_push_code ->
634 returnBc (push `appOL` more_push_code)
636 | Just (CCall ccall_spec) <- isFCallId_maybe fn
637 = panic "schemeT.do_pushery: unexpected ccall"
640 Just con -> returnBc (
641 (PACK con narg_words `consOL`
642 mkSLIDE 1 (d - narg_words - s)) `snocOL`
646 -> pushAtom True d p (AnnVar fn)
647 `thenBc` \ (push, arg_words) ->
648 returnBc (push `appOL` mkSLIDE (narg_words+arg_words)
653 {- Deal with a CCall. Taggedly push the args onto the stack R->L,
654 deferencing ForeignObj#s and (ToDo: adjusting addrs to point to
655 payloads in Ptr/Byte arrays). Then, generate the marshalling
656 (machine) code for the ccall, and create bytecodes to call that and
657 then return in the right way.
659 generateCCall :: Int -> Sequel -- stack and sequel depths
661 -> CCallSpec -- where to call
662 -> Id -- of target, for type info
663 -> [AnnExpr Id VarSet] -- args (atoms)
666 generateCCall d0 s p ccall_spec@(CCallSpec target cconv safety) fn args_r_to_l
669 addr_usizeW = untaggedSizeW AddrRep
670 addr_tsizeW = taggedSizeW AddrRep
672 -- Get the args on the stack, with tags and suitably
673 -- dereferenced for the CCall. For each arg, return the
674 -- depth to the first word of the bits for that arg, and the
675 -- PrimRep of what was actually pushed.
677 pargs d [] = returnBc []
679 = let rep_arg = atomRep a
681 -- Don't push the FO; instead push the Addr# it
684 -> pushAtom False{-irrelevant-} d p a
685 `thenBc` \ (push_fo, _) ->
686 let foro_szW = taggedSizeW ForeignObjRep
687 d_now = d + addr_tsizeW
688 code = push_fo `appOL` toOL [
689 UPK_TAG addr_usizeW 0 0,
690 SLIDE addr_tsizeW foro_szW
692 in pargs d_now az `thenBc` \ rest ->
693 returnBc ((code, AddrRep) : rest)
696 -> pargs (d + addr_tsizeW) az `thenBc` \ rest ->
697 parg_ArrayishRep arrPtrsHdrSize d p a
699 returnBc ((code,AddrRep):rest)
702 -> pargs (d + addr_tsizeW) az `thenBc` \ rest ->
703 parg_ArrayishRep arrWordsHdrSize d p a
705 returnBc ((code,AddrRep):rest)
707 -- Default case: push taggedly, but otherwise intact.
709 -> pushAtom True d p a `thenBc` \ (code_a, sz_a) ->
710 pargs (d+sz_a) az `thenBc` \ rest ->
711 returnBc ((code_a, rep_arg) : rest)
713 -- Do magic for Ptr/Byte arrays. Push a ptr to the array on
714 -- the stack but then advance it over the headers, so as to
715 -- point to the payload.
716 parg_ArrayishRep hdrSizeW d p a
717 = pushAtom False{-irrel-} d p a `thenBc` \ (push_fo, _) ->
718 -- The ptr points at the header. Advance it over the
719 -- header and then pretend this is an Addr# (push a tag).
720 returnBc (push_fo `snocOL`
721 SWIZZLE 0 (hdrSizeW * untaggedSizeW PtrRep
724 PUSH_TAG addr_usizeW)
727 pargs d0 args_r_to_l `thenBc` \ code_n_reps ->
729 (pushs_arg, a_reps_pushed_r_to_l) = unzip code_n_reps
731 push_args = concatOL pushs_arg
732 d_after_args = d0 + sum (map taggedSizeW a_reps_pushed_r_to_l)
734 | null a_reps_pushed_r_to_l || head a_reps_pushed_r_to_l /= VoidRep
735 = panic "ByteCodeGen.generateCCall: missing or invalid World token?"
737 = reverse (tail a_reps_pushed_r_to_l)
739 -- Now: a_reps_pushed_RAW are the reps which are actually on the stack.
740 -- push_args is the code to do that.
741 -- d_after_args is the stack depth once the args are on.
743 -- Get the result rep.
744 (returns_void, r_rep)
745 = case maybe_getCCallReturnRep (idType fn) of
746 Nothing -> (True, VoidRep)
747 Just rr -> (False, rr)
749 Because the Haskell stack grows down, the a_reps refer to
750 lowest to highest addresses in that order. The args for the call
751 are on the stack. Now push an unboxed, tagged Addr# indicating
752 the C function to call. Then push a dummy placeholder for the
753 result. Finally, emit a CCALL insn with an offset pointing to the
754 Addr# just pushed, and a literal field holding the mallocville
755 address of the piece of marshalling code we generate.
756 So, just prior to the CCALL insn, the stack looks like this
757 (growing down, as usual):
762 Addr# address_of_C_fn
763 <placeholder-for-result#> (must be an unboxed type)
765 The interpreter then calls the marshall code mentioned
766 in the CCALL insn, passing it (& <placeholder-for-result#>),
767 that is, the addr of the topmost word in the stack.
768 When this returns, the placeholder will have been
769 filled in. The placeholder is slid down to the sequel
770 depth, and we RETURN.
772 This arrangement makes it simple to do f-i-dynamic since the Addr#
773 value is the first arg anyway. It also has the virtue that the
774 stack is GC-understandable at all times.
776 The marshalling code is generated specifically for this
777 call site, and so knows exactly the (Haskell) stack
778 offsets of the args, fn address and placeholder. It
779 copies the args to the C stack, calls the stacked addr,
780 and parks the result back in the placeholder. The interpreter
781 calls it as a normal C call, assuming it has a signature
782 void marshall_code ( StgWord* ptr_to_top_of_stack )
784 -- resolve static address
788 -> returnBc (False, panic "ByteCodeGen.generateCCall(dyn)")
790 -> let sym_to_find = _UNPK_ target in
791 ioToBc (lookupSymbol sym_to_find) `thenBc` \res ->
793 Just aa -> case aa of Ptr a# -> returnBc (True, A# a#)
794 Nothing -> ioToBc (linkFail "ByteCodeGen.generateCCall"
797 -> pprPanic "ByteCodeGen.generateCCall: casm" (ppr ccall_spec)
799 get_target_info `thenBc` \ (is_static, static_target_addr) ->
802 -- Get the arg reps, zapping the leading Addr# in the dynamic case
803 a_reps -- | trace (showSDoc (ppr a_reps_pushed_RAW)) False = error "???"
804 | is_static = a_reps_pushed_RAW
805 | otherwise = if null a_reps_pushed_RAW
806 then panic "ByteCodeGen.generateCCall: dyn with no args"
807 else tail a_reps_pushed_RAW
810 (push_Addr, d_after_Addr)
812 = (toOL [PUSH_UBX (Right static_target_addr) addr_usizeW,
813 PUSH_TAG addr_usizeW],
814 d_after_args + addr_tsizeW)
815 | otherwise -- is already on the stack
816 = (nilOL, d_after_args)
818 -- Push the return placeholder. For a call returning nothing,
819 -- this is a VoidRep (tag).
820 r_usizeW = untaggedSizeW r_rep
821 r_tsizeW = taggedSizeW r_rep
822 d_after_r = d_after_Addr + r_tsizeW
823 r_lit = mkDummyLiteral r_rep
824 push_r = (if returns_void
826 else unitOL (PUSH_UBX (Left r_lit) r_usizeW))
828 unitOL (PUSH_TAG r_usizeW)
830 -- generate the marshalling code we're going to call
833 arg1_offW = r_tsizeW + addr_tsizeW
834 args_offW = map (arg1_offW +)
835 (init (scanl (+) 0 (map taggedSizeW a_reps)))
837 ioToBc (mkMarshalCode cconv
838 (r_offW, r_rep) addr_offW
839 (zip args_offW a_reps)) `thenBc` \ addr_of_marshaller ->
840 recordMallocBc addr_of_marshaller `thenBc_`
843 do_call = unitOL (CCALL addr_of_marshaller)
845 wrapup = mkSLIDE r_tsizeW (d_after_r - r_tsizeW - s)
846 `snocOL` RETURN r_rep
848 --trace (show (arg1_offW, args_offW , (map taggedSizeW a_reps) )) (
851 push_Addr `appOL` push_r `appOL` do_call `appOL` wrapup
856 -- Make a dummy literal, to be used as a placeholder for FFI return
857 -- values on the stack.
858 mkDummyLiteral :: PrimRep -> Literal
861 CharRep -> MachChar 0
863 WordRep -> MachWord 0
864 DoubleRep -> MachDouble 0
865 FloatRep -> MachFloat 0
866 AddrRep | taggedSizeW AddrRep == taggedSizeW WordRep -> MachWord 0
867 _ -> moan64 "mkDummyLiteral" (ppr pr)
871 -- PrelGHC.Char# -> PrelGHC.State# PrelGHC.RealWorld
872 -- -> (# PrelGHC.State# PrelGHC.RealWorld, PrelGHC.Int# #)
875 -- and check that an unboxed pair is returned wherein the first arg is VoidRep'd.
877 -- Alternatively, for call-targets returning nothing, convert
879 -- PrelGHC.Char# -> PrelGHC.State# PrelGHC.RealWorld
880 -- -> (# PrelGHC.State# PrelGHC.RealWorld #)
884 maybe_getCCallReturnRep :: Type -> Maybe PrimRep
885 maybe_getCCallReturnRep fn_ty
886 = let (a_tys, r_ty) = splitRepFunTys fn_ty
888 = if isSingleton r_reps then Nothing else Just (r_reps !! 1)
890 = case splitTyConApp_maybe (repType r_ty) of
891 (Just (tyc, tys)) -> (tyc, map typePrimRep tys)
893 ok = ( ( r_reps `lengthIs` 2 && VoidRep == head r_reps)
894 || r_reps == [VoidRep] )
895 && isUnboxedTupleTyCon r_tycon
896 && case maybe_r_rep_to_go of
898 Just r_rep -> r_rep /= PtrRep
899 -- if it was, it would be impossible
900 -- to create a valid return value
901 -- placeholder on the stack
902 blargh = pprPanic "maybe_getCCallReturn: can't handle:"
905 --trace (showSDoc (ppr (a_reps, r_reps))) (
906 if ok then maybe_r_rep_to_go else blargh
909 atomRep (AnnVar v) = typePrimRep (idType v)
910 atomRep (AnnLit l) = literalPrimRep l
911 atomRep (AnnNote n b) = atomRep (snd b)
912 atomRep (AnnApp f (_, AnnType _)) = atomRep (snd f)
913 atomRep (AnnLam x e) | isTyVar x = atomRep (snd e)
914 atomRep other = pprPanic "atomRep" (ppr (deAnnotate (undefined,other)))
917 -- Compile code which expects an unboxed Int on the top of stack,
918 -- (call it i), and pushes the i'th closure in the supplied list
920 implement_tagToId :: [Name] -> BcM BCInstrList
921 implement_tagToId names
922 = ASSERT(not (null names))
923 getLabelsBc (length names) `thenBc` \ labels ->
924 getLabelBc `thenBc` \ label_fail ->
925 getLabelBc `thenBc` \ label_exit ->
926 zip4 labels (tail labels ++ [label_fail])
927 [0 ..] names `bind` \ infos ->
928 map (mkStep label_exit) infos `bind` \ steps ->
929 returnBc (concatOL steps
931 toOL [LABEL label_fail, CASEFAIL, LABEL label_exit])
933 mkStep l_exit (my_label, next_label, n, name_for_n)
934 = toOL [LABEL my_label,
935 TESTEQ_I n next_label,
936 PUSH_G (Left name_for_n),
940 -- Make code to unpack the top-of-stack constructor onto the stack,
941 -- adding tags for the unboxed bits. Takes the PrimReps of the
942 -- constructor's arguments. off_h and off_s are travelling offsets
943 -- along the constructor and the stack.
945 -- Supposing a constructor in the heap has layout
947 -- Itbl p_1 ... p_i np_1 ... np_j
949 -- then we add to the stack, shown growing down, the following:
961 -- so that in the common case (ptrs only) a single UNPACK instr can
962 -- copy all the payload of the constr onto the stack with no further ado.
964 mkUnpackCode :: [Id] -- constr args
965 -> Int -- depth before unpack
966 -> BCEnv -- env before unpack
967 -> (BCInstrList, Int, BCEnv)
968 mkUnpackCode vars d p
969 = --trace ("mkUnpackCode: " ++ showSDocDebug (ppr vars)
970 -- ++ " --> " ++ show d' ++ "\n" ++ showSDocDebug (ppBCEnv p')
972 (code_p `appOL` code_np, d', p')
976 vreps = [(var, typePrimRep (idType var)) | var <- vars]
978 -- ptrs and nonptrs, forward
979 vreps_p = filter (isFollowableRep.snd) vreps
980 vreps_np = filter (not.isFollowableRep.snd) vreps
982 -- the order in which we will augment the environment
983 vreps_env = reverse vreps_p ++ reverse vreps_np
986 vreps_env_tszsw = map (taggedSizeW.snd) vreps_env
987 p' = addListToFM p (zip (map fst vreps_env)
988 (mkStackOffsets d vreps_env_tszsw))
989 d' = d + sum vreps_env_tszsw
991 -- code to unpack the ptrs
992 ptrs_szw = sum (map (untaggedSizeW.snd) vreps_p)
993 code_p | null vreps_p = nilOL
994 | otherwise = unitOL (UNPACK ptrs_szw)
996 -- code to unpack the nonptrs
997 vreps_env_uszw = sum (map (untaggedSizeW.snd) vreps_env)
998 code_np = do_nptrs vreps_env_uszw ptrs_szw (reverse (map snd vreps_np))
999 do_nptrs off_h off_s [] = nilOL
1000 do_nptrs off_h off_s (npr:nprs)
1001 | npr `elem` [IntRep, WordRep, FloatRep, DoubleRep, CharRep, AddrRep]
1004 = moan64 "ByteCodeGen.mkUnpackCode" (ppr npr)
1006 approved = UPK_TAG usizeW (off_h-usizeW) off_s `consOL` theRest
1007 theRest = do_nptrs (off_h-usizeW) (off_s + tsizeW) nprs
1008 usizeW = untaggedSizeW npr
1009 tsizeW = taggedSizeW npr
1012 -- Push an atom onto the stack, returning suitable code & number of
1013 -- stack words used. Pushes it either tagged or untagged, since
1014 -- pushAtom is used to set up the stack prior to copying into the
1015 -- heap for both APs (requiring tags) and constructors (which don't).
1017 -- NB this means NO GC between pushing atoms for a constructor and
1018 -- copying them into the heap. It probably also means that
1019 -- tail calls MUST be of the form atom{atom ... atom} since if the
1020 -- expression head was allowed to be arbitrary, there could be GC
1021 -- in between pushing the arg atoms and completing the head.
1022 -- (not sure; perhaps the allocate/doYouWantToGC interface means this
1023 -- isn't a problem; but only if arbitrary graph construction for the
1024 -- head doesn't leave this BCO, since GC might happen at the start of
1025 -- each BCO (we consult doYouWantToGC there).
1027 -- Blargh. JRS 001206
1029 -- NB (further) that the env p must map each variable to the highest-
1030 -- numbered stack slot for it. For example, if the stack has depth 4
1031 -- and we tagged-ly push (v :: Int#) on it, the value will be in stack[4],
1032 -- the tag in stack[5], the stack will have depth 6, and p must map v to
1033 -- 5 and not to 4. Stack locations are numbered from zero, so a depth
1034 -- 6 stack has valid words 0 .. 5.
1036 pushAtom :: Bool -> Int -> BCEnv -> AnnExpr' Id VarSet -> BcM (BCInstrList, Int)
1037 pushAtom tagged d p (AnnVar v)
1039 | idPrimRep v == VoidRep
1040 = if tagged then returnBc (unitOL (PUSH_TAG 0), 1)
1041 else panic "ByteCodeGen.pushAtom(VoidRep,untaggedly)"
1044 = pprPanic "pushAtom: shouldn't get an FCallId here" (ppr v)
1046 | Just primop <- isPrimOpId_maybe v
1047 = returnBc (unitOL (PUSH_G (Right primop)), 1)
1051 str = "\npushAtom " ++ showSDocDebug (ppr v)
1052 ++ " :: " ++ showSDocDebug (pprType (idType v))
1053 ++ ", depth = " ++ show d
1054 ++ ", tagged = " ++ show tagged ++ ", env =\n" ++
1055 showSDocDebug (ppBCEnv p)
1056 ++ " --> words: " ++ show (snd result) ++ "\n" ++
1057 showSDoc (nest 4 (vcat (map ppr (fromOL (fst result)))))
1058 ++ "\nendPushAtom " ++ showSDocDebug (ppr v)
1062 = case lookupBCEnv_maybe p v of
1063 Just d_v -> (toOL (nOfThem nwords (PUSH_L (d-d_v+sz_t-2))), nwords)
1064 Nothing -> ASSERT(sz_t == 1) (unitOL (PUSH_G (Left nm)), nwords)
1066 nm = case isDataConId_maybe v of
1068 Nothing -> getName v
1070 sz_t = taggedIdSizeW v
1071 sz_u = untaggedIdSizeW v
1072 nwords = if tagged then sz_t else sz_u
1076 pushAtom True d p (AnnLit lit)
1077 = pushAtom False d p (AnnLit lit) `thenBc` \ (ubx_code, ubx_size) ->
1078 returnBc (ubx_code `snocOL` PUSH_TAG ubx_size, 1 + ubx_size)
1080 pushAtom False d p (AnnLit lit)
1082 MachWord w -> code WordRep
1083 MachInt i -> code IntRep
1084 MachFloat r -> code FloatRep
1085 MachDouble r -> code DoubleRep
1086 MachChar c -> code CharRep
1087 MachStr s -> pushStr s
1090 = let size_host_words = untaggedSizeW rep
1091 in returnBc (unitOL (PUSH_UBX (Left lit) size_host_words),
1095 = let getMallocvilleAddr
1097 CharStr s i -> returnBc (A# s)
1099 FastString _ l ba ->
1100 -- sigh, a string in the heap is no good to us.
1101 -- We need a static C pointer, since the type of
1102 -- a string literal is Addr#. So, copy the string
1103 -- into C land and introduce a memory leak
1104 -- at the same time.
1106 -- CAREFUL! Chars are 32 bits in ghc 4.09+
1107 in ioToBc (mallocBytes (n+1)) `thenBc` \ (Ptr a#) ->
1108 recordMallocBc (A# a#) `thenBc_`
1110 do strncpy (Ptr a#) ba (fromIntegral n)
1111 writeCharOffAddr (A# a#) n '\0'
1114 other -> panic "ByteCodeGen.pushAtom.pushStr"
1116 getMallocvilleAddr `thenBc` \ addr ->
1117 -- Get the addr on the stack, untaggedly
1118 returnBc (unitOL (PUSH_UBX (Right addr) 1), 1)
1124 pushAtom tagged d p (AnnApp f (_, AnnType _))
1125 = pushAtom tagged d p (snd f)
1127 pushAtom tagged d p (AnnNote note e)
1128 = pushAtom tagged d p (snd e)
1130 pushAtom tagged d p (AnnLam x e)
1132 = pushAtom tagged d p (snd e)
1134 pushAtom tagged d p other
1135 = pprPanic "ByteCodeGen.pushAtom"
1136 (pprCoreExpr (deAnnotate (undefined, other)))
1138 foreign import "strncpy" strncpy :: Ptr a -> ByteArray# -> CInt -> IO ()
1141 -- Given a bunch of alts code and their discrs, do the donkey work
1142 -- of making a multiway branch using a switch tree.
1143 -- What a load of hassle!
1144 mkMultiBranch :: Maybe Int -- # datacons in tycon, if alg alt
1145 -- a hint; generates better code
1146 -- Nothing is always safe
1147 -> [(Discr, BCInstrList)]
1149 mkMultiBranch maybe_ncons raw_ways
1150 = let d_way = filter (isNoDiscr.fst) raw_ways
1151 notd_ways = naturalMergeSortLe
1152 (\w1 w2 -> leAlt (fst w1) (fst w2))
1153 (filter (not.isNoDiscr.fst) raw_ways)
1155 mkTree :: [(Discr, BCInstrList)] -> Discr -> Discr -> BcM BCInstrList
1156 mkTree [] range_lo range_hi = returnBc the_default
1158 mkTree [val] range_lo range_hi
1159 | range_lo `eqAlt` range_hi
1160 = returnBc (snd val)
1162 = getLabelBc `thenBc` \ label_neq ->
1163 returnBc (mkTestEQ (fst val) label_neq
1165 `appOL` unitOL (LABEL label_neq)
1166 `appOL` the_default))
1168 mkTree vals range_lo range_hi
1169 = let n = length vals `div` 2
1170 vals_lo = take n vals
1171 vals_hi = drop n vals
1172 v_mid = fst (head vals_hi)
1174 getLabelBc `thenBc` \ label_geq ->
1175 mkTree vals_lo range_lo (dec v_mid) `thenBc` \ code_lo ->
1176 mkTree vals_hi v_mid range_hi `thenBc` \ code_hi ->
1177 returnBc (mkTestLT v_mid label_geq
1179 `appOL` unitOL (LABEL label_geq)
1183 = case d_way of [] -> unitOL CASEFAIL
1186 -- None of these will be needed if there are no non-default alts
1187 (mkTestLT, mkTestEQ, init_lo, init_hi)
1189 = panic "mkMultiBranch: awesome foursome"
1191 = case fst (head notd_ways) of {
1192 DiscrI _ -> ( \(DiscrI i) fail_label -> TESTLT_I i fail_label,
1193 \(DiscrI i) fail_label -> TESTEQ_I i fail_label,
1196 DiscrF _ -> ( \(DiscrF f) fail_label -> TESTLT_F f fail_label,
1197 \(DiscrF f) fail_label -> TESTEQ_F f fail_label,
1200 DiscrD _ -> ( \(DiscrD d) fail_label -> TESTLT_D d fail_label,
1201 \(DiscrD d) fail_label -> TESTEQ_D d fail_label,
1204 DiscrP _ -> ( \(DiscrP i) fail_label -> TESTLT_P i fail_label,
1205 \(DiscrP i) fail_label -> TESTEQ_P i fail_label,
1207 DiscrP algMaxBound )
1210 (algMinBound, algMaxBound)
1211 = case maybe_ncons of
1212 Just n -> (0, n - 1)
1213 Nothing -> (minBound, maxBound)
1215 (DiscrI i1) `eqAlt` (DiscrI i2) = i1 == i2
1216 (DiscrF f1) `eqAlt` (DiscrF f2) = f1 == f2
1217 (DiscrD d1) `eqAlt` (DiscrD d2) = d1 == d2
1218 (DiscrP i1) `eqAlt` (DiscrP i2) = i1 == i2
1219 NoDiscr `eqAlt` NoDiscr = True
1222 (DiscrI i1) `leAlt` (DiscrI i2) = i1 <= i2
1223 (DiscrF f1) `leAlt` (DiscrF f2) = f1 <= f2
1224 (DiscrD d1) `leAlt` (DiscrD d2) = d1 <= d2
1225 (DiscrP i1) `leAlt` (DiscrP i2) = i1 <= i2
1226 NoDiscr `leAlt` NoDiscr = True
1229 isNoDiscr NoDiscr = True
1232 dec (DiscrI i) = DiscrI (i-1)
1233 dec (DiscrP i) = DiscrP (i-1)
1234 dec other = other -- not really right, but if you
1235 -- do cases on floating values, you'll get what you deserve
1237 -- same snotty comment applies to the following
1239 minD, maxD :: Double
1245 mkTree notd_ways init_lo init_hi
1249 %************************************************************************
1251 \subsection{Supporting junk for the compilation schemes}
1253 %************************************************************************
1257 -- Describes case alts
1265 instance Outputable Discr where
1266 ppr (DiscrI i) = int i
1267 ppr (DiscrF f) = text (show f)
1268 ppr (DiscrD d) = text (show d)
1269 ppr (DiscrP i) = int i
1270 ppr NoDiscr = text "DEF"
1273 -- Find things in the BCEnv (the what's-on-the-stack-env)
1274 -- See comment preceding pushAtom for precise meaning of env contents
1275 --lookupBCEnv :: BCEnv -> Id -> Int
1276 --lookupBCEnv env nm
1277 -- = case lookupFM env nm of
1278 -- Nothing -> pprPanic "lookupBCEnv"
1279 -- (ppr nm $$ char ' ' $$ vcat (map ppr (fmToList env)))
1282 lookupBCEnv_maybe :: BCEnv -> Id -> Maybe Int
1283 lookupBCEnv_maybe = lookupFM
1286 taggedIdSizeW, untaggedIdSizeW :: Id -> Int
1287 taggedIdSizeW = taggedSizeW . typePrimRep . idType
1288 untaggedIdSizeW = untaggedSizeW . typePrimRep . idType
1290 unboxedTupleException :: a
1291 unboxedTupleException
1294 ("Bytecode generator can't handle unboxed tuples. Possibly due\n" ++
1295 "\tto foreign import/export decls in source. Workaround:\n" ++
1296 "\tcompile this module to a .o file, then restart session."))
1299 mkSLIDE n d = if d == 0 then nilOL else unitOL (SLIDE n d)
1304 %************************************************************************
1306 \subsection{The bytecode generator's monad}
1308 %************************************************************************
1312 = BcM_State { bcos :: [ProtoBCO Name], -- accumulates completed BCOs
1313 nextlabel :: Int, -- for generating local labels
1314 malloced :: [Addr] } -- ptrs malloced for current BCO
1315 -- Should be free()d when it is GCd
1316 type BcM r = BcM_State -> IO (BcM_State, r)
1318 ioToBc :: IO a -> BcM a
1319 ioToBc io st = do x <- io
1322 runBc :: BcM_State -> BcM r -> IO (BcM_State, r)
1323 runBc st0 m = do (st1, res) <- m st0
1326 thenBc :: BcM a -> (a -> BcM b) -> BcM b
1327 thenBc expr cont st0
1328 = do (st1, q) <- expr st0
1329 (st2, r) <- cont q st1
1332 thenBc_ :: BcM a -> BcM b -> BcM b
1333 thenBc_ expr cont st0
1334 = do (st1, q) <- expr st0
1335 (st2, r) <- cont st1
1338 returnBc :: a -> BcM a
1339 returnBc result st = return (st, result)
1342 mapBc :: (a -> BcM b) -> [a] -> BcM [b]
1343 mapBc f [] = returnBc []
1345 = f x `thenBc` \ r ->
1346 mapBc f xs `thenBc` \ rs ->
1349 emitBc :: ([Addr] -> ProtoBCO Name) -> BcM ()
1351 = return (st{bcos = bco (malloced st) : bcos st, malloced=[]}, ())
1355 | not (null (malloced st))
1356 = panic "ByteCodeGen.newbcoBc: missed prior emitBc?"
1360 recordMallocBc :: Addr -> BcM ()
1362 = return (st{malloced = a : malloced st}, ())
1364 getLabelBc :: BcM Int
1366 = return (st{nextlabel = 1 + nextlabel st}, nextlabel st)
1368 getLabelsBc :: Int -> BcM [Int]
1370 = let ctr = nextlabel st
1371 in return (st{nextlabel = ctr+n}, [ctr .. ctr+n-1])