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,
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 import Var ( isTyVar )
38 import VarSet ( VarSet, varSetElems )
39 import PrimRep ( isFollowableRep )
40 import CmdLineOpts ( DynFlags, DynFlag(..) )
41 import ErrUtils ( showPass, dumpIfSet_dyn )
42 import Unique ( mkPseudoUnique3 )
43 import FastString ( FastString(..) )
44 import Panic ( GhcException(..) )
45 import PprType ( pprType )
46 import SMRep ( arrWordsHdrSize, arrPtrsHdrSize )
47 import Constants ( wORD_SIZE )
48 import ByteCodeInstr ( BCInstr(..), ProtoBCO(..), nameOfProtoBCO, bciStackUse )
49 import ByteCodeItbls ( ItblEnv, mkITbls )
50 import ByteCodeLink ( UnlinkedBCO, UnlinkedBCOExpr, assembleBCO,
51 ClosureEnv, HValue, filterNameMap,
52 iNTERP_STACK_CHECK_THRESH )
53 import ByteCodeFFI ( taggedSizeW, untaggedSizeW, mkMarshalCode )
54 import Linker ( lookupSymbol )
56 import List ( intersperse, sortBy, zip4 )
57 import Foreign ( Ptr(..), mallocBytes )
58 import Addr ( Addr(..), writeCharOffAddr )
59 import CTypes ( CInt )
60 import Exception ( throwDyn )
62 import PrelBase ( Int(..) )
63 import PrelGHC ( ByteArray# )
64 import PrelIOBase ( IO(..) )
69 %************************************************************************
71 \subsection{Functions visible from outside this module.}
73 %************************************************************************
77 byteCodeGen :: DynFlags
80 -> IO ([UnlinkedBCO], ItblEnv)
81 byteCodeGen dflags binds local_tycons local_classes
82 = do showPass dflags "ByteCodeGen"
83 let tycs = local_tycons ++ map classTyCon local_classes
84 itblenv <- mkITbls tycs
86 let flatBinds = concatMap getBind binds
87 getBind (NonRec bndr rhs) = [(bndr, freeVars rhs)]
88 getBind (Rec binds) = [(bndr, freeVars rhs) | (bndr,rhs) <- binds]
90 (BcM_State proto_bcos final_ctr mallocd, ())
91 <- runBc (BcM_State [] 0 [])
92 (mapBc (schemeR True) flatBinds `thenBc_` returnBc ())
94 when (not (null mallocd))
95 (panic "ByteCodeGen.byteCodeGen: missing final emitBc?")
97 dumpIfSet_dyn dflags Opt_D_dump_BCOs
98 "Proto-bcos" (vcat (intersperse (char ' ') (map ppr proto_bcos)))
100 bcos <- mapM assembleBCO proto_bcos
102 return (bcos, itblenv)
105 -- Returns: (the root BCO for this expression,
106 -- a list of auxilary BCOs resulting from compiling closures)
107 coreExprToBCOs :: DynFlags
109 -> IO UnlinkedBCOExpr
110 coreExprToBCOs dflags expr
111 = do showPass dflags "ByteCodeGen"
113 -- create a totally bogus name for the top-level BCO; this
114 -- should be harmless, since it's never used for anything
115 let invented_id = mkSysLocal SLIT("Expr-Top-Level") (mkPseudoUnique3 0)
116 (panic "invented_id's type")
117 let invented_name = idName invented_id
119 (BcM_State all_proto_bcos final_ctr mallocd, ())
120 <- runBc (BcM_State [] 0 [])
121 (schemeR True (invented_id, freeVars expr))
123 when (not (null mallocd))
124 (panic "ByteCodeGen.coreExprToBCOs: missing final emitBc?")
126 dumpIfSet_dyn dflags Opt_D_dump_BCOs
127 "Proto-bcos" (vcat (intersperse (char ' ') (map ppr all_proto_bcos)))
130 = case filter ((== invented_name).nameOfProtoBCO) all_proto_bcos of
131 [root_bco] -> root_bco
133 = filter ((/= invented_name).nameOfProtoBCO) all_proto_bcos
135 auxiliary_bcos <- mapM assembleBCO auxiliary_proto_bcos
136 root_bco <- assembleBCO root_proto_bco
138 return (root_bco, auxiliary_bcos)
141 %************************************************************************
143 \subsection{Compilation schema for the bytecode generator.}
145 %************************************************************************
149 type BCInstrList = OrdList BCInstr
151 type Sequel = Int -- back off to this depth before ENTER
153 -- Maps Ids to the offset from the stack _base_ so we don't have
154 -- to mess with it after each push/pop.
155 type BCEnv = FiniteMap Id Int -- To find vars on the stack
157 ppBCEnv :: BCEnv -> SDoc
160 $$ nest 4 (vcat (map pp_one (sortBy cmp_snd (fmToList p))))
163 pp_one (var, offset) = int offset <> colon <+> ppr var
164 cmp_snd x y = compare (snd x) (snd y)
166 -- Create a BCO and do a spot of peephole optimisation on the insns
168 mkProtoBCO nm instrs_ordlist origin mallocd_blocks
169 = ProtoBCO nm maybe_with_stack_check origin mallocd_blocks
171 -- Overestimate the stack usage (in words) of this BCO,
172 -- and if >= iNTERP_STACK_CHECK_THRESH, add an explicit
173 -- stack check. (The interpreter always does a stack check
174 -- for iNTERP_STACK_CHECK_THRESH words at the start of each
175 -- BCO anyway, so we only need to add an explicit on in the
176 -- (hopefully rare) cases when the (overestimated) stack use
177 -- exceeds iNTERP_STACK_CHECK_THRESH.
178 maybe_with_stack_check
179 | stack_overest >= 65535
180 = pprPanic "mkProtoBCO: stack use won't fit in 16 bits"
182 | stack_overest >= iNTERP_STACK_CHECK_THRESH
183 = (STKCHECK stack_overest) : peep_d
185 = peep_d -- the supposedly common case
187 stack_overest = sum (map bciStackUse peep_d)
188 + 10 {- just to be really really sure -}
191 -- Merge local pushes
192 peep_d = peep (fromOL instrs_ordlist)
194 peep (PUSH_L off1 : PUSH_L off2 : PUSH_L off3 : rest)
195 = PUSH_LLL off1 (off2-1) (off3-2) : peep rest
196 peep (PUSH_L off1 : PUSH_L off2 : rest)
197 = PUSH_LL off1 (off2-1) : peep rest
204 -- Compile code for the right hand side of a let binding.
205 -- Park the resulting BCO in the monad. Also requires the
206 -- variable to which this value was bound, so as to give the
207 -- resulting BCO a name. Bool indicates top-levelness.
209 schemeR :: Bool -> (Id, AnnExpr Id VarSet) -> BcM ()
210 schemeR is_top (nm, rhs)
214 $$ (ppr.filter (not.isTyVar).varSetElems.fst) rhs
215 $$ pprCoreExpr (deAnnotate rhs)
221 = schemeR_wrk is_top rhs nm (collect [] rhs)
224 collect xs (_, AnnNote note e)
226 collect xs (_, AnnLam x e)
227 = collect (if isTyVar x then xs else (x:xs)) e
228 collect xs not_lambda
229 = (reverse xs, not_lambda)
231 schemeR_wrk is_top original_body nm (args, body)
232 | Just dcon <- maybe_toplevel_null_con_rhs
233 = --trace ("nullary constructor! " ++ showSDocDebug (ppr nm)) (
234 emitBc (mkProtoBCO (getName nm) (toOL [PACK dcon 0, ENTER])
235 (Right original_body))
239 = let fvs = filter (not.isTyVar) (varSetElems (fst original_body))
240 all_args = reverse args ++ fvs
241 szsw_args = map taggedIdSizeW all_args
242 szw_args = sum szsw_args
243 p_init = listToFM (zip all_args (mkStackOffsets 0 szsw_args))
244 argcheck = unitOL (ARGCHECK szw_args)
246 schemeE szw_args 0 p_init body `thenBc` \ body_code ->
247 emitBc (mkProtoBCO (getName nm) (appOL argcheck body_code)
248 (Right original_body))
251 maybe_toplevel_null_con_rhs
252 | is_top && null args
253 = case nukeTyArgs (snd body) of
255 -> case isDataConId_maybe v_wrk of
257 Just dc_wrk | nm == dataConWrapId dc_wrk
265 nukeTyArgs (AnnApp f (_, AnnType _)) = nukeTyArgs (snd f)
266 nukeTyArgs other = other
269 -- Let szsw be the sizes in words of some items pushed onto the stack,
270 -- which has initial depth d'. Return the values which the stack environment
271 -- should map these items to.
272 mkStackOffsets :: Int -> [Int] -> [Int]
273 mkStackOffsets original_depth szsw
274 = map (subtract 1) (tail (scanl (+) original_depth szsw))
276 -- Compile code to apply the given expression to the remaining args
277 -- on the stack, returning a HNF.
278 schemeE :: Int -> Sequel -> BCEnv -> AnnExpr Id VarSet -> BcM BCInstrList
280 -- Delegate tail-calls to schemeT.
281 schemeE d s p e@(fvs, AnnApp f a)
282 = schemeT d s p (fvs, AnnApp f a)
284 schemeE d s p e@(fvs, AnnVar v)
285 | isFollowableRep v_rep
286 = -- Ptr-ish thing; push it in the normal way
287 schemeT d s p (fvs, AnnVar v)
290 = -- returning an unboxed value. Heave it on the stack, SLIDE, and RETURN.
291 pushAtom True d p (AnnVar v) `thenBc` \ (push, szw) ->
292 returnBc (push -- value onto stack
293 `appOL` mkSLIDE szw (d-s) -- clear to sequel
294 `snocOL` RETURN v_rep) -- go
296 v_rep = typePrimRep (idType v)
298 schemeE d s p (fvs, AnnLit literal)
299 = pushAtom True d p (AnnLit literal) `thenBc` \ (push, szw) ->
300 let l_rep = literalPrimRep literal
301 in returnBc (push -- value onto stack
302 `appOL` mkSLIDE szw (d-s) -- clear to sequel
303 `snocOL` RETURN l_rep) -- go
305 schemeE d s p (fvs, AnnLet binds b)
306 = let (xs,rhss) = case binds of AnnNonRec x rhs -> ([x],[rhs])
307 AnnRec xs_n_rhss -> unzip xs_n_rhss
309 fvss = map (filter (not.isTyVar).varSetElems.fst) rhss
311 -- Sizes of tagged free vars, + 1 for the fn
312 sizes = map (\rhs_fvs -> 1 + sum (map taggedIdSizeW rhs_fvs)) fvss
314 -- This p', d' defn is safe because all the items being pushed
315 -- are ptrs, so all have size 1. d' and p' reflect the stack
316 -- after the closures have been allocated in the heap (but not
317 -- filled in), and pointers to them parked on the stack.
318 p' = addListToFM p (zipE xs (mkStackOffsets d (nOfThem n 1)))
321 infos = zipE4 fvss sizes xs [n, n-1 .. 1]
322 zipE = zipEqual "schemeE"
323 zipE4 = zipWith4Equal "schemeE" (\a b c d -> (a,b,c,d))
325 -- ToDo: don't build thunks for things with no free variables
326 buildThunk dd ([], size, id, off)
327 = returnBc (PUSH_G (Left (getName id))
328 `consOL` unitOL (MKAP (off+size-1) size))
329 buildThunk dd ((fv:fvs), size, id, off)
330 = pushAtom True dd p' (AnnVar fv)
331 `thenBc` \ (push_code, pushed_szw) ->
332 buildThunk (dd+pushed_szw) (fvs, size, id, off)
333 `thenBc` \ more_push_code ->
334 returnBc (push_code `appOL` more_push_code)
336 genThunkCode = mapBc (buildThunk d') infos `thenBc` \ tcodes ->
337 returnBc (concatOL tcodes)
339 allocCode = toOL (map ALLOC sizes)
341 schemeE d' s p' b `thenBc` \ bodyCode ->
342 mapBc (schemeR False) (zip xs rhss) `thenBc_`
343 genThunkCode `thenBc` \ thunkCode ->
344 returnBc (allocCode `appOL` thunkCode `appOL` bodyCode)
350 schemeE d s p (fvs_case, AnnCase (fvs_scrut, scrut) bndr
351 [(DEFAULT, [], (fvs_rhs, rhs))])
353 | let isFunType var_type
354 = case splitTyConApp_maybe var_type of
355 Just (tycon,_) | isFunTyCon tycon -> True
357 ty_bndr = repType (idType bndr)
358 in isFunType ty_bndr || isTyVarTy ty_bndr
361 -- case scrut::suspect of bndr { DEFAULT -> rhs }
363 -- let bndr = scrut in rhs
364 -- when suspect is polymorphic or arrowtyped
365 -- So the required strictness properties are not observed.
366 -- At some point, must fix this properly.
370 (AnnNonRec bndr (fvs_scrut, scrut)) (fvs_rhs, rhs)
373 in trace ("WARNING: ignoring polymorphic case in interpreted mode.\n" ++
374 " Possibly due to strict polymorphic/functional constructor args.\n" ++
375 " Your program may leak space unexpectedly.\n")
376 (schemeE d s p new_expr)
380 {- Convert case .... of (# VoidRep'd-thing, a #) -> ...
382 case .... of a -> ...
383 Use a as the name of the binder too.
385 Also case .... of (# a #) -> ...
387 case .... of a -> ...
389 schemeE d s p (fvs, AnnCase scrut bndr [(DataAlt dc, [bind1, bind2], rhs)])
390 | isUnboxedTupleCon dc && VoidRep == typePrimRep (idType bind1)
391 = --trace "automagic mashing of case alts (# VoidRep, a #)" (
392 schemeE d s p (fvs, AnnCase scrut bind2 [(DEFAULT, [bind2], rhs)])
395 schemeE d s p (fvs, AnnCase scrut bndr [(DataAlt dc, [bind1], rhs)])
396 | isUnboxedTupleCon dc
397 = --trace "automagic mashing of case alts (# a #)" (
398 schemeE d s p (fvs, AnnCase scrut bind1 [(DEFAULT, [bind1], rhs)])
401 schemeE d s p (fvs, AnnCase scrut bndr alts)
403 -- Top of stack is the return itbl, as usual.
404 -- underneath it is the pointer to the alt_code BCO.
405 -- When an alt is entered, it assumes the returned value is
406 -- on top of the itbl.
409 -- Env and depth in which to compile the alts, not including
410 -- any vars bound by the alts themselves
411 d' = d + ret_frame_sizeW + taggedIdSizeW bndr
412 p' = addToFM p bndr (d' - 1)
414 scrut_primrep = typePrimRep (idType bndr)
416 | scrut_primrep == PtrRep
418 | scrut_primrep `elem`
419 [CharRep, AddrRep, WordRep, IntRep, FloatRep, DoubleRep,
420 VoidRep, Int8Rep, Int16Rep, Int32Rep, Int64Rep,
421 Word8Rep, Word16Rep, Word32Rep, Word64Rep]
424 = pprPanic "ByteCodeGen.schemeE" (ppr scrut_primrep)
426 -- given an alt, return a discr and code for it.
427 codeAlt alt@(discr, binds_f, rhs)
429 = let (unpack_code, d_after_unpack, p_after_unpack)
430 = mkUnpackCode (filter (not.isTyVar) binds_f) d' p'
431 in schemeE d_after_unpack s p_after_unpack rhs
432 `thenBc` \ rhs_code ->
433 returnBc (my_discr alt, unpack_code `appOL` rhs_code)
435 = ASSERT(null binds_f)
436 schemeE d' s p' rhs `thenBc` \ rhs_code ->
437 returnBc (my_discr alt, rhs_code)
439 my_discr (DEFAULT, binds, rhs) = NoDiscr
440 my_discr (DataAlt dc, binds, rhs)
441 | isUnboxedTupleCon dc
442 = unboxedTupleException
444 = DiscrP (dataConTag dc - fIRST_TAG)
445 my_discr (LitAlt l, binds, rhs)
446 = case l of MachInt i -> DiscrI (fromInteger i)
447 MachFloat r -> DiscrF (fromRational r)
448 MachDouble r -> DiscrD (fromRational r)
449 MachChar i -> DiscrI i
450 _ -> pprPanic "schemeE(AnnCase).my_discr" (ppr l)
453 | not isAlgCase = Nothing
455 = case [dc | (DataAlt dc, _, _) <- alts] of
457 (dc:_) -> Just (tyConFamilySize (dataConTyCon dc))
460 mapBc codeAlt alts `thenBc` \ alt_stuff ->
461 mkMultiBranch maybe_ncons alt_stuff `thenBc` \ alt_final ->
463 alt_final_ac = ARGCHECK (taggedIdSizeW bndr) `consOL` alt_final
464 alt_bco_name = getName bndr
465 alt_bco = mkProtoBCO alt_bco_name alt_final_ac (Left alts)
467 schemeE (d + ret_frame_sizeW)
468 (d + ret_frame_sizeW) p scrut `thenBc` \ scrut_code ->
470 emitBc alt_bco `thenBc_`
471 returnBc (PUSH_AS alt_bco_name scrut_primrep `consOL` scrut_code)
474 schemeE d s p (fvs, AnnNote note body)
478 = pprPanic "ByteCodeGen.schemeE: unhandled case"
479 (pprCoreExpr (deAnnotate other))
482 -- Compile code to do a tail call. Specifically, push the fn,
483 -- slide the on-stack app back down to the sequel depth,
484 -- and enter. Four cases:
487 -- An application "PrelGHC.tagToEnum# <type> unboxed-int".
488 -- The int will be on the stack. Generate a code sequence
489 -- to convert it to the relevant constructor, SLIDE and ENTER.
491 -- 1. A nullary constructor. Push its closure on the stack
492 -- and SLIDE and RETURN.
494 -- 2. (Another nasty hack). Spot (# a::VoidRep, b #) and treat
495 -- it simply as b -- since the representations are identical
496 -- (the VoidRep takes up zero stack space). Also, spot
497 -- (# b #) and treat it as b.
499 -- 3. The fn denotes a ccall. Defer to generateCCall.
501 -- 4. Application of a non-nullary constructor, by defn saturated.
502 -- Split the args into ptrs and non-ptrs, and push the nonptrs,
503 -- then the ptrs, and then do PACK and RETURN.
505 -- 5. Otherwise, it must be a function call. Push the args
506 -- right to left, SLIDE and ENTER.
508 schemeT :: Int -- Stack depth
509 -> Sequel -- Sequel depth
510 -> BCEnv -- stack env
516 -- | trace ("schemeT: env in = \n" ++ showSDocDebug (ppBCEnv p)) False
517 -- = panic "schemeT ?!?!"
519 -- | trace ("\nschemeT\n" ++ showSDoc (pprCoreExpr (deAnnotate app)) ++ "\n") False
523 | Just (arg, constr_names) <- maybe_is_tagToEnum_call
524 = pushAtom True d p arg `thenBc` \ (push, arg_words) ->
525 implement_tagToId constr_names `thenBc` \ tagToId_sequence ->
526 returnBc (push `appOL` tagToId_sequence
527 `appOL` mkSLIDE 1 (d+arg_words-s)
531 | is_con_call && null args_r_to_l
533 (PUSH_G (Left (getName con)) `consOL` mkSLIDE 1 (d-s))
538 | let isVoidRepAtom (_, AnnVar v) = VoidRep == typePrimRep (idType v)
539 isVoidRepAtom (_, AnnNote n e) = isVoidRepAtom e
540 in is_con_call && isUnboxedTupleCon con
541 && ( (length args_r_to_l == 2 && isVoidRepAtom (last (args_r_to_l)))
542 || (length args_r_to_l == 1)
544 = --trace (if length args_r_to_l == 1
545 -- then "schemeT: unboxed singleton"
546 -- else "schemeT: unboxed pair with Void first component") (
547 schemeT d s p (head args_r_to_l)
551 | Just (CCall ccall_spec) <- isFCallId_maybe fn
552 = generateCCall d s p ccall_spec fn args_r_to_l
556 = if is_con_call && isUnboxedTupleCon con
557 then unboxedTupleException
558 else do_pushery d (map snd args_final_r_to_l)
561 -- Detect and extract relevant info for the tagToEnum kludge.
562 maybe_is_tagToEnum_call
563 = let extract_constr_Names ty
564 = case splitTyConApp_maybe (repType ty) of
565 (Just (tyc, [])) | isDataTyCon tyc
566 -> map getName (tyConDataCons tyc)
567 other -> panic "maybe_is_tagToEnum_call.extract_constr_Ids"
570 (_, AnnApp (_, AnnApp (_, AnnVar v) (_, AnnType t)) arg)
571 -> case isPrimOpId_maybe v of
572 Just TagToEnumOp -> Just (snd arg, extract_constr_Names t)
576 -- Extract the args (R->L) and fn
577 (args_r_to_l_raw, fn) = chomp app
581 AnnApp f a -> case chomp f of (az, f) -> (a:az, f)
582 AnnNote n e -> chomp e
583 other -> pprPanic "schemeT"
584 (ppr (deAnnotate (panic "schemeT.chomp", other)))
586 args_r_to_l = filter (not.isTypeAtom.snd) args_r_to_l_raw
587 isTypeAtom (AnnType _) = True
590 -- decide if this is a constructor call, and rearrange
591 -- args appropriately.
592 maybe_dcon = isDataConId_maybe fn
593 is_con_call = case maybe_dcon of Nothing -> False; Just _ -> True
594 (Just con) = maybe_dcon
600 = filter (not.isPtr.snd) args_r_to_l ++ filter (isPtr.snd) args_r_to_l
601 where isPtr = isFollowableRep . atomRep
603 -- make code to push the args and then do the SLIDE-ENTER thing
604 tag_when_push = not is_con_call
605 narg_words = sum (map (get_arg_szw . atomRep . snd) args_r_to_l)
606 get_arg_szw = if tag_when_push then taggedSizeW else untaggedSizeW
608 do_pushery d (arg:args)
609 = pushAtom tag_when_push d p arg `thenBc` \ (push, arg_words) ->
610 do_pushery (d+arg_words) args `thenBc` \ more_push_code ->
611 returnBc (push `appOL` more_push_code)
613 | Just (CCall ccall_spec) <- isFCallId_maybe fn
614 = panic "schemeT.do_pushery: unexpected ccall"
617 Just con -> returnBc (
618 (PACK con narg_words `consOL`
619 mkSLIDE 1 (d - narg_words - s)) `snocOL`
623 -> pushAtom True d p (AnnVar fn)
624 `thenBc` \ (push, arg_words) ->
625 returnBc (push `appOL` mkSLIDE (narg_words+arg_words)
631 {- Deal with a CCall. Taggedly push the args onto the stack R->L,
632 deferencing ForeignObj#s and (ToDo: adjusting addrs to point to
633 payloads in Ptr/Byte arrays). Then, generate the marshalling
634 (machine) code for the ccall, and create bytecodes to call that and
635 then return in the right way.
637 generateCCall :: Int -> Sequel -- stack and sequel depths
639 -> CCallSpec -- where to call
640 -> Id -- of target, for type info
641 -> [AnnExpr Id VarSet] -- args (atoms)
644 generateCCall d0 s p ccall_spec@(CCallSpec target cconv safety) fn args_r_to_l
647 addr_usizeW = untaggedSizeW AddrRep
648 addr_tsizeW = taggedSizeW AddrRep
650 -- Get the args on the stack, with tags and suitably
651 -- dereferenced for the CCall. For each arg, return the
652 -- depth to the first word of the bits for that arg, and the
653 -- PrimRep of what was actually pushed.
655 pargs d [] = returnBc []
657 = let rep_arg = atomRep a
659 -- Don't push the FO; instead push the Addr# it
662 -> pushAtom False{-irrelevant-} d p a
663 `thenBc` \ (push_fo, _) ->
664 let foro_szW = taggedSizeW ForeignObjRep
665 d_now = d + addr_tsizeW
666 code = push_fo `appOL` toOL [
667 UPK_TAG addr_usizeW 0 0,
668 SLIDE addr_tsizeW foro_szW
670 in pargs d_now az `thenBc` \ rest ->
671 returnBc ((code, AddrRep) : rest)
674 -> pargs (d + addr_tsizeW) az `thenBc` \ rest ->
675 parg_ArrayishRep arrPtrsHdrSize d p a
677 returnBc ((code,AddrRep):rest)
680 -> pargs (d + addr_tsizeW) az `thenBc` \ rest ->
681 parg_ArrayishRep arrWordsHdrSize d p a
683 returnBc ((code,AddrRep):rest)
685 -- Default case: push taggedly, but otherwise intact.
687 -> pushAtom True d p a `thenBc` \ (code_a, sz_a) ->
688 pargs (d+sz_a) az `thenBc` \ rest ->
689 returnBc ((code_a, rep_arg) : rest)
691 -- Do magic for Ptr/Byte arrays. Push a ptr to the array on
692 -- the stack but then advance it over the headers, so as to
693 -- point to the payload.
694 parg_ArrayishRep hdrSizeW d p a
695 = pushAtom False{-irrel-} d p a `thenBc` \ (push_fo, _) ->
696 -- The ptr points at the header. Advance it over the
697 -- header and then pretend this is an Addr# (push a tag).
698 returnBc (push_fo `snocOL`
699 SWIZZLE 0 (hdrSizeW * untaggedSizeW PtrRep
702 PUSH_TAG addr_usizeW)
705 pargs d0 args_r_to_l `thenBc` \ code_n_reps ->
707 (pushs_arg, a_reps_pushed_r_to_l) = unzip code_n_reps
709 push_args = concatOL pushs_arg
710 d_after_args = d0 + sum (map taggedSizeW a_reps_pushed_r_to_l)
712 | null a_reps_pushed_r_to_l || head a_reps_pushed_r_to_l /= VoidRep
713 = panic "ByteCodeGen.generateCCall: missing or invalid World token?"
715 = reverse (tail a_reps_pushed_r_to_l)
717 -- Now: a_reps_pushed_RAW are the reps which are actually on the stack.
718 -- push_args is the code to do that.
719 -- d_after_args is the stack depth once the args are on.
721 -- Get the result rep.
722 (returns_void, r_rep)
723 = case maybe_getCCallReturnRep (idType fn) of
724 Nothing -> (True, VoidRep)
725 Just rr -> (False, rr)
727 Because the Haskell stack grows down, the a_reps refer to
728 lowest to highest addresses in that order. The args for the call
729 are on the stack. Now push an unboxed, tagged Addr# indicating
730 the C function to call. Then push a dummy placeholder for the
731 result. Finally, emit a CCALL insn with an offset pointing to the
732 Addr# just pushed, and a literal field holding the mallocville
733 address of the piece of marshalling code we generate.
734 So, just prior to the CCALL insn, the stack looks like this
735 (growing down, as usual):
740 Addr# address_of_C_fn
741 <placeholder-for-result#> (must be an unboxed type)
743 The interpreter then calls the marshall code mentioned
744 in the CCALL insn, passing it (& <placeholder-for-result#>),
745 that is, the addr of the topmost word in the stack.
746 When this returns, the placeholder will have been
747 filled in. The placeholder is slid down to the sequel
748 depth, and we RETURN.
750 This arrangement makes it simple to do f-i-dynamic since the Addr#
751 value is the first arg anyway. It also has the virtue that the
752 stack is GC-understandable at all times.
754 The marshalling code is generated specifically for this
755 call site, and so knows exactly the (Haskell) stack
756 offsets of the args, fn address and placeholder. It
757 copies the args to the C stack, calls the stacked addr,
758 and parks the result back in the placeholder. The interpreter
759 calls it as a normal C call, assuming it has a signature
760 void marshall_code ( StgWord* ptr_to_top_of_stack )
762 -- resolve static address
766 -> returnBc (False, panic "ByteCodeGen.generateCCall(dyn)")
768 -> ioToBc (lookupSymbol (_UNPK_ target)) `thenBc` \res ->
770 Just aa -> case aa of Ptr a# -> returnBc (True, A# a#)
771 Nothing -> returnBc invalid
775 invalid = pprPanic ("ByteCodeGen.generateCCall: unfindable "
776 ++ "symbol or otherwise invalid target")
779 get_target_info `thenBc` \ (is_static, static_target_addr) ->
782 -- Get the arg reps, zapping the leading Addr# in the dynamic case
783 a_reps -- | trace (showSDoc (ppr a_reps_pushed_RAW)) False = error "???"
784 | is_static = a_reps_pushed_RAW
785 | otherwise = if null a_reps_pushed_RAW
786 then panic "ByteCodeGen.generateCCall: dyn with no args"
787 else tail a_reps_pushed_RAW
790 (push_Addr, d_after_Addr)
792 = (toOL [PUSH_UBX (Right static_target_addr) addr_usizeW,
793 PUSH_TAG addr_usizeW],
794 d_after_args + addr_tsizeW)
795 | otherwise -- is already on the stack
796 = (nilOL, d_after_args)
798 -- Push the return placeholder. For a call returning nothing,
799 -- this is a VoidRep (tag).
800 r_usizeW = untaggedSizeW r_rep
801 r_tsizeW = taggedSizeW r_rep
802 d_after_r = d_after_Addr + r_tsizeW
803 r_lit = mkDummyLiteral r_rep
804 push_r = (if returns_void
806 else unitOL (PUSH_UBX (Left r_lit) r_usizeW))
808 unitOL (PUSH_TAG r_usizeW)
810 -- generate the marshalling code we're going to call
813 arg1_offW = r_tsizeW + addr_tsizeW
814 args_offW = map (arg1_offW +)
815 (init (scanl (+) 0 (map taggedSizeW a_reps)))
817 ioToBc (mkMarshalCode cconv
818 (r_offW, r_rep) addr_offW
819 (zip args_offW a_reps)) `thenBc` \ addr_of_marshaller ->
820 recordMallocBc addr_of_marshaller `thenBc_`
823 do_call = unitOL (CCALL addr_of_marshaller)
825 wrapup = mkSLIDE r_tsizeW (d_after_r - r_tsizeW - s)
826 `snocOL` RETURN r_rep
828 --trace (show (arg1_offW, args_offW , (map taggedSizeW a_reps) )) (
831 push_Addr `appOL` push_r `appOL` do_call `appOL` wrapup
836 -- Make a dummy literal, to be used as a placeholder for FFI return
837 -- values on the stack.
838 mkDummyLiteral :: PrimRep -> Literal
841 CharRep -> MachChar 0
843 DoubleRep -> MachDouble 0
844 FloatRep -> MachFloat 0
845 AddrRep | taggedSizeW AddrRep == taggedSizeW WordRep -> MachWord 0
846 _ -> pprPanic "mkDummyLiteral" (ppr pr)
850 -- PrelGHC.Char# -> PrelGHC.State# PrelGHC.RealWorld
851 -- -> (# PrelGHC.State# PrelGHC.RealWorld, PrelGHC.Int# #)
854 -- and check that an unboxed pair is returned wherein the first arg is VoidRep'd.
856 -- Alternatively, for call-targets returning nothing, convert
858 -- PrelGHC.Char# -> PrelGHC.State# PrelGHC.RealWorld
859 -- -> (# PrelGHC.State# PrelGHC.RealWorld #)
863 maybe_getCCallReturnRep :: Type -> Maybe PrimRep
864 maybe_getCCallReturnRep fn_ty
865 = let (a_tys, r_ty) = splitRepFunTys fn_ty
867 = if length r_reps == 1 then Nothing else Just (r_reps !! 1)
869 = case splitTyConApp_maybe (repType r_ty) of
870 (Just (tyc, tys)) -> (tyc, map typePrimRep tys)
872 ok = ( (length r_reps == 2 && VoidRep == head r_reps)
873 || r_reps == [VoidRep] )
874 && isUnboxedTupleTyCon r_tycon
875 && case maybe_r_rep_to_go of
877 Just r_rep -> r_rep /= PtrRep
878 -- if it was, it would be impossible
879 -- to create a valid return value
880 -- placeholder on the stack
881 blargh = pprPanic "maybe_getCCallReturn: can't handle:"
884 --trace (showSDoc (ppr (a_reps, r_reps))) (
885 if ok then maybe_r_rep_to_go else blargh
888 atomRep (AnnVar v) = typePrimRep (idType v)
889 atomRep (AnnLit l) = literalPrimRep l
890 atomRep (AnnNote n b) = atomRep (snd b)
891 atomRep (AnnApp f (_, AnnType _)) = atomRep (snd f)
892 atomRep (AnnLam x e) | isTyVar x = atomRep (snd e)
893 atomRep other = pprPanic "atomRep" (ppr (deAnnotate (undefined,other)))
896 -- Compile code which expects an unboxed Int on the top of stack,
897 -- (call it i), and pushes the i'th closure in the supplied list
899 implement_tagToId :: [Name] -> BcM BCInstrList
900 implement_tagToId names
901 = ASSERT(not (null names))
902 getLabelsBc (length names) `thenBc` \ labels ->
903 getLabelBc `thenBc` \ label_fail ->
904 getLabelBc `thenBc` \ label_exit ->
905 zip4 labels (tail labels ++ [label_fail])
906 [0 ..] names `bind` \ infos ->
907 map (mkStep label_exit) infos `bind` \ steps ->
908 returnBc (concatOL steps
910 toOL [LABEL label_fail, CASEFAIL, LABEL label_exit])
912 mkStep l_exit (my_label, next_label, n, name_for_n)
913 = toOL [LABEL my_label,
914 TESTEQ_I n next_label,
915 PUSH_G (Left name_for_n),
919 -- Make code to unpack the top-of-stack constructor onto the stack,
920 -- adding tags for the unboxed bits. Takes the PrimReps of the
921 -- constructor's arguments. off_h and off_s are travelling offsets
922 -- along the constructor and the stack.
924 -- Supposing a constructor in the heap has layout
926 -- Itbl p_1 ... p_i np_1 ... np_j
928 -- then we add to the stack, shown growing down, the following:
940 -- so that in the common case (ptrs only) a single UNPACK instr can
941 -- copy all the payload of the constr onto the stack with no further ado.
943 mkUnpackCode :: [Id] -- constr args
944 -> Int -- depth before unpack
945 -> BCEnv -- env before unpack
946 -> (BCInstrList, Int, BCEnv)
947 mkUnpackCode vars d p
948 = --trace ("mkUnpackCode: " ++ showSDocDebug (ppr vars)
949 -- ++ " --> " ++ show d' ++ "\n" ++ showSDocDebug (ppBCEnv p')
951 (code_p `appOL` code_np, d', p')
955 vreps = [(var, typePrimRep (idType var)) | var <- vars]
957 -- ptrs and nonptrs, forward
958 vreps_p = filter (isFollowableRep.snd) vreps
959 vreps_np = filter (not.isFollowableRep.snd) vreps
961 -- the order in which we will augment the environment
962 vreps_env = reverse vreps_p ++ reverse vreps_np
965 vreps_env_tszsw = map (taggedSizeW.snd) vreps_env
966 p' = addListToFM p (zip (map fst vreps_env)
967 (mkStackOffsets d vreps_env_tszsw))
968 d' = d + sum vreps_env_tszsw
970 -- code to unpack the ptrs
971 ptrs_szw = sum (map (untaggedSizeW.snd) vreps_p)
972 code_p | null vreps_p = nilOL
973 | otherwise = unitOL (UNPACK ptrs_szw)
975 -- code to unpack the nonptrs
976 vreps_env_uszw = sum (map (untaggedSizeW.snd) vreps_env)
977 code_np = do_nptrs vreps_env_uszw ptrs_szw (reverse (map snd vreps_np))
978 do_nptrs off_h off_s [] = nilOL
979 do_nptrs off_h off_s (npr:nprs)
980 | npr `elem` [IntRep, WordRep, FloatRep, DoubleRep, CharRep, AddrRep]
983 = pprPanic "ByteCodeGen.mkUnpackCode" (ppr npr)
985 approved = UPK_TAG usizeW (off_h-usizeW) off_s `consOL` theRest
986 theRest = do_nptrs (off_h-usizeW) (off_s + tsizeW) nprs
987 usizeW = untaggedSizeW npr
988 tsizeW = taggedSizeW npr
991 -- Push an atom onto the stack, returning suitable code & number of
992 -- stack words used. Pushes it either tagged or untagged, since
993 -- pushAtom is used to set up the stack prior to copying into the
994 -- heap for both APs (requiring tags) and constructors (which don't).
996 -- NB this means NO GC between pushing atoms for a constructor and
997 -- copying them into the heap. It probably also means that
998 -- tail calls MUST be of the form atom{atom ... atom} since if the
999 -- expression head was allowed to be arbitrary, there could be GC
1000 -- in between pushing the arg atoms and completing the head.
1001 -- (not sure; perhaps the allocate/doYouWantToGC interface means this
1002 -- isn't a problem; but only if arbitrary graph construction for the
1003 -- head doesn't leave this BCO, since GC might happen at the start of
1004 -- each BCO (we consult doYouWantToGC there).
1006 -- Blargh. JRS 001206
1008 -- NB (further) that the env p must map each variable to the highest-
1009 -- numbered stack slot for it. For example, if the stack has depth 4
1010 -- and we tagged-ly push (v :: Int#) on it, the value will be in stack[4],
1011 -- the tag in stack[5], the stack will have depth 6, and p must map v to
1012 -- 5 and not to 4. Stack locations are numbered from zero, so a depth
1013 -- 6 stack has valid words 0 .. 5.
1015 pushAtom :: Bool -> Int -> BCEnv -> AnnExpr' Id VarSet -> BcM (BCInstrList, Int)
1016 pushAtom tagged d p (AnnVar v)
1018 | idPrimRep v == VoidRep
1019 = if tagged then returnBc (unitOL (PUSH_TAG 0), 1)
1020 else panic "ByteCodeGen.pushAtom(VoidRep,untaggedly)"
1023 = pprPanic "pushAtom: shouldn't get an FCallId here" (ppr v)
1025 | Just primop <- isPrimOpId_maybe v
1026 = returnBc (unitOL (PUSH_G (Right primop)), 1)
1030 str = "\npushAtom " ++ showSDocDebug (ppr v)
1031 ++ " :: " ++ showSDocDebug (pprType (idType v))
1032 ++ ", depth = " ++ show d
1033 ++ ", tagged = " ++ show tagged ++ ", env =\n" ++
1034 showSDocDebug (ppBCEnv p)
1035 ++ " --> words: " ++ show (snd result) ++ "\n" ++
1036 showSDoc (nest 4 (vcat (map ppr (fromOL (fst result)))))
1037 ++ "\nendPushAtom " ++ showSDocDebug (ppr v)
1041 = case lookupBCEnv_maybe p v of
1042 Just d_v -> (toOL (nOfThem nwords (PUSH_L (d-d_v+sz_t-2))), nwords)
1043 Nothing -> ASSERT(sz_t == 1) (unitOL (PUSH_G (Left nm)), nwords)
1045 nm = case isDataConId_maybe v of
1047 Nothing -> getName v
1049 sz_t = taggedIdSizeW v
1050 sz_u = untaggedIdSizeW v
1051 nwords = if tagged then sz_t else sz_u
1055 pushAtom True d p (AnnLit lit)
1056 = pushAtom False d p (AnnLit lit) `thenBc` \ (ubx_code, ubx_size) ->
1057 returnBc (ubx_code `snocOL` PUSH_TAG ubx_size, 1 + ubx_size)
1059 pushAtom False d p (AnnLit lit)
1061 MachWord w -> code WordRep
1062 MachInt i -> code IntRep
1063 MachFloat r -> code FloatRep
1064 MachDouble r -> code DoubleRep
1065 MachChar c -> code CharRep
1066 MachStr s -> pushStr s
1069 = let size_host_words = untaggedSizeW rep
1070 in returnBc (unitOL (PUSH_UBX (Left lit) size_host_words),
1074 = let getMallocvilleAddr
1076 CharStr s i -> returnBc (A# s)
1078 FastString _ l ba ->
1079 -- sigh, a string in the heap is no good to us.
1080 -- We need a static C pointer, since the type of
1081 -- a string literal is Addr#. So, copy the string
1082 -- into C land and introduce a memory leak
1083 -- at the same time.
1085 -- CAREFUL! Chars are 32 bits in ghc 4.09+
1086 in ioToBc (mallocBytes (n+1)) `thenBc` \ (Ptr a#) ->
1087 recordMallocBc (A# a#) `thenBc_`
1089 do strncpy (Ptr a#) ba (fromIntegral n)
1090 writeCharOffAddr (A# a#) n '\0'
1093 other -> panic "ByteCodeGen.pushAtom.pushStr"
1095 getMallocvilleAddr `thenBc` \ addr ->
1096 -- Get the addr on the stack, untaggedly
1097 returnBc (unitOL (PUSH_UBX (Right addr) 1), 1)
1103 pushAtom tagged d p (AnnApp f (_, AnnType _))
1104 = pushAtom tagged d p (snd f)
1106 pushAtom tagged d p (AnnNote note e)
1107 = pushAtom tagged d p (snd e)
1109 pushAtom tagged d p (AnnLam x e)
1111 = pushAtom tagged d p (snd e)
1113 pushAtom tagged d p other
1114 = pprPanic "ByteCodeGen.pushAtom"
1115 (pprCoreExpr (deAnnotate (undefined, other)))
1117 foreign import "strncpy" strncpy :: Ptr a -> ByteArray# -> CInt -> IO ()
1120 -- Given a bunch of alts code and their discrs, do the donkey work
1121 -- of making a multiway branch using a switch tree.
1122 -- What a load of hassle!
1123 mkMultiBranch :: Maybe Int -- # datacons in tycon, if alg alt
1124 -- a hint; generates better code
1125 -- Nothing is always safe
1126 -> [(Discr, BCInstrList)]
1128 mkMultiBranch maybe_ncons raw_ways
1129 = let d_way = filter (isNoDiscr.fst) raw_ways
1130 notd_ways = naturalMergeSortLe
1131 (\w1 w2 -> leAlt (fst w1) (fst w2))
1132 (filter (not.isNoDiscr.fst) raw_ways)
1134 mkTree :: [(Discr, BCInstrList)] -> Discr -> Discr -> BcM BCInstrList
1135 mkTree [] range_lo range_hi = returnBc the_default
1137 mkTree [val] range_lo range_hi
1138 | range_lo `eqAlt` range_hi
1139 = returnBc (snd val)
1141 = getLabelBc `thenBc` \ label_neq ->
1142 returnBc (mkTestEQ (fst val) label_neq
1144 `appOL` unitOL (LABEL label_neq)
1145 `appOL` the_default))
1147 mkTree vals range_lo range_hi
1148 = let n = length vals `div` 2
1149 vals_lo = take n vals
1150 vals_hi = drop n vals
1151 v_mid = fst (head vals_hi)
1153 getLabelBc `thenBc` \ label_geq ->
1154 mkTree vals_lo range_lo (dec v_mid) `thenBc` \ code_lo ->
1155 mkTree vals_hi v_mid range_hi `thenBc` \ code_hi ->
1156 returnBc (mkTestLT v_mid label_geq
1158 `appOL` unitOL (LABEL label_geq)
1162 = case d_way of [] -> unitOL CASEFAIL
1165 -- None of these will be needed if there are no non-default alts
1166 (mkTestLT, mkTestEQ, init_lo, init_hi)
1168 = panic "mkMultiBranch: awesome foursome"
1170 = case fst (head notd_ways) of {
1171 DiscrI _ -> ( \(DiscrI i) fail_label -> TESTLT_I i fail_label,
1172 \(DiscrI i) fail_label -> TESTEQ_I i fail_label,
1175 DiscrF _ -> ( \(DiscrF f) fail_label -> TESTLT_F f fail_label,
1176 \(DiscrF f) fail_label -> TESTEQ_F f fail_label,
1179 DiscrD _ -> ( \(DiscrD d) fail_label -> TESTLT_D d fail_label,
1180 \(DiscrD d) fail_label -> TESTEQ_D d fail_label,
1183 DiscrP _ -> ( \(DiscrP i) fail_label -> TESTLT_P i fail_label,
1184 \(DiscrP i) fail_label -> TESTEQ_P i fail_label,
1186 DiscrP algMaxBound )
1189 (algMinBound, algMaxBound)
1190 = case maybe_ncons of
1191 Just n -> (0, n - 1)
1192 Nothing -> (minBound, maxBound)
1194 (DiscrI i1) `eqAlt` (DiscrI i2) = i1 == i2
1195 (DiscrF f1) `eqAlt` (DiscrF f2) = f1 == f2
1196 (DiscrD d1) `eqAlt` (DiscrD d2) = d1 == d2
1197 (DiscrP i1) `eqAlt` (DiscrP i2) = i1 == i2
1198 NoDiscr `eqAlt` NoDiscr = True
1201 (DiscrI i1) `leAlt` (DiscrI i2) = i1 <= i2
1202 (DiscrF f1) `leAlt` (DiscrF f2) = f1 <= f2
1203 (DiscrD d1) `leAlt` (DiscrD d2) = d1 <= d2
1204 (DiscrP i1) `leAlt` (DiscrP i2) = i1 <= i2
1205 NoDiscr `leAlt` NoDiscr = True
1208 isNoDiscr NoDiscr = True
1211 dec (DiscrI i) = DiscrI (i-1)
1212 dec (DiscrP i) = DiscrP (i-1)
1213 dec other = other -- not really right, but if you
1214 -- do cases on floating values, you'll get what you deserve
1216 -- same snotty comment applies to the following
1218 minD, maxD :: Double
1224 mkTree notd_ways init_lo init_hi
1228 %************************************************************************
1230 \subsection{Supporting junk for the compilation schemes}
1232 %************************************************************************
1236 -- Describes case alts
1244 instance Outputable Discr where
1245 ppr (DiscrI i) = int i
1246 ppr (DiscrF f) = text (show f)
1247 ppr (DiscrD d) = text (show d)
1248 ppr (DiscrP i) = int i
1249 ppr NoDiscr = text "DEF"
1252 -- Find things in the BCEnv (the what's-on-the-stack-env)
1253 -- See comment preceding pushAtom for precise meaning of env contents
1254 --lookupBCEnv :: BCEnv -> Id -> Int
1255 --lookupBCEnv env nm
1256 -- = case lookupFM env nm of
1257 -- Nothing -> pprPanic "lookupBCEnv"
1258 -- (ppr nm $$ char ' ' $$ vcat (map ppr (fmToList env)))
1261 lookupBCEnv_maybe :: BCEnv -> Id -> Maybe Int
1262 lookupBCEnv_maybe = lookupFM
1265 taggedIdSizeW, untaggedIdSizeW :: Id -> Int
1266 taggedIdSizeW = taggedSizeW . typePrimRep . idType
1267 untaggedIdSizeW = untaggedSizeW . typePrimRep . idType
1269 unboxedTupleException :: a
1270 unboxedTupleException
1273 ("Bytecode generator can't handle unboxed tuples. Possibly due\n" ++
1274 "\tto foreign import/export decls in source. Workaround:\n" ++
1275 "\tcompile this module to a .o file, then restart session."))
1278 mkSLIDE n d = if d == 0 then nilOL else unitOL (SLIDE n d)
1283 %************************************************************************
1285 \subsection{The bytecode generator's monad}
1287 %************************************************************************
1291 = BcM_State { bcos :: [ProtoBCO Name], -- accumulates completed BCOs
1292 nextlabel :: Int, -- for generating local labels
1293 malloced :: [Addr] } -- ptrs malloced for current BCO
1294 -- Should be free()d when it is GCd
1295 type BcM r = BcM_State -> IO (BcM_State, r)
1297 ioToBc :: IO a -> BcM a
1298 ioToBc io st = do x <- io
1301 runBc :: BcM_State -> BcM r -> IO (BcM_State, r)
1302 runBc st0 m = do (st1, res) <- m st0
1305 thenBc :: BcM a -> (a -> BcM b) -> BcM b
1306 thenBc expr cont st0
1307 = do (st1, q) <- expr st0
1308 (st2, r) <- cont q st1
1311 thenBc_ :: BcM a -> BcM b -> BcM b
1312 thenBc_ expr cont st0
1313 = do (st1, q) <- expr st0
1314 (st2, r) <- cont st1
1317 returnBc :: a -> BcM a
1318 returnBc result st = return (st, result)
1321 mapBc :: (a -> BcM b) -> [a] -> BcM [b]
1322 mapBc f [] = returnBc []
1324 = f x `thenBc` \ r ->
1325 mapBc f xs `thenBc` \ rs ->
1328 emitBc :: ([Addr] -> ProtoBCO Name) -> BcM ()
1330 = return (st{bcos = bco (malloced st) : bcos st, malloced=[]}, ())
1334 | not (null (malloced st))
1335 = panic "ByteCodeGen.newbcoBc: missed prior emitBc?"
1339 recordMallocBc :: Addr -> BcM ()
1341 = return (st{malloced = a : malloced st}, ())
1343 getLabelBc :: BcM Int
1345 = return (st{nextlabel = 1 + nextlabel st}, nextlabel st)
1347 getLabelsBc :: Int -> BcM [Int]
1349 = let ctr = nextlabel st
1350 in return (st{nextlabel = ctr+n}, [ctr .. ctr+n-1])