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 isSingleton, lengthIs )
38 import Var ( isTyVar )
39 import VarSet ( VarSet, varSetElems )
40 import PrimRep ( isFollowableRep )
41 import CmdLineOpts ( DynFlags, DynFlag(..) )
42 import ErrUtils ( showPass, dumpIfSet_dyn )
43 import Unique ( mkPseudoUnique3 )
44 import FastString ( FastString(..) )
45 import Panic ( GhcException(..) )
46 import PprType ( pprType )
47 import SMRep ( arrWordsHdrSize, arrPtrsHdrSize )
48 import Constants ( wORD_SIZE )
49 import ByteCodeInstr ( BCInstr(..), ProtoBCO(..), nameOfProtoBCO, bciStackUse )
50 import ByteCodeItbls ( ItblEnv, mkITbls )
51 import ByteCodeLink ( UnlinkedBCO, UnlinkedBCOExpr, assembleBCO,
52 ClosureEnv, HValue, filterNameMap, linkFail,
53 iNTERP_STACK_CHECK_THRESH )
54 import ByteCodeFFI ( taggedSizeW, untaggedSizeW, mkMarshalCode, moan64 )
55 import Linker ( lookupSymbol )
57 import List ( intersperse, sortBy, zip4 )
58 import Foreign ( Ptr(..), mallocBytes )
59 import Addr ( Addr(..), writeCharOffAddr )
60 import CTypes ( CInt )
61 import Exception ( throwDyn )
63 import PrelBase ( Int(..) )
64 import PrelGHC ( ByteArray# )
65 import PrelIOBase ( IO(..) )
70 %************************************************************************
72 \subsection{Functions visible from outside this module.}
74 %************************************************************************
78 byteCodeGen :: DynFlags
81 -> IO ([UnlinkedBCO], ItblEnv)
82 byteCodeGen dflags binds local_tycons local_classes
83 = do showPass dflags "ByteCodeGen"
84 let tycs = local_tycons ++ map classTyCon local_classes
85 itblenv <- mkITbls tycs
87 let flatBinds = concatMap getBind binds
88 getBind (NonRec bndr rhs) = [(bndr, freeVars rhs)]
89 getBind (Rec binds) = [(bndr, freeVars rhs) | (bndr,rhs) <- binds]
91 (BcM_State proto_bcos final_ctr mallocd, ())
92 <- runBc (BcM_State [] 0 [])
93 (mapBc (schemeR True) flatBinds `thenBc_` returnBc ())
95 when (not (null mallocd))
96 (panic "ByteCodeGen.byteCodeGen: missing final emitBc?")
98 dumpIfSet_dyn dflags Opt_D_dump_BCOs
99 "Proto-bcos" (vcat (intersperse (char ' ') (map ppr proto_bcos)))
101 bcos <- mapM assembleBCO proto_bcos
103 return (bcos, itblenv)
106 -- Returns: (the root BCO for this expression,
107 -- a list of auxilary BCOs resulting from compiling closures)
108 coreExprToBCOs :: DynFlags
110 -> IO UnlinkedBCOExpr
111 coreExprToBCOs dflags expr
112 = do showPass dflags "ByteCodeGen"
114 -- create a totally bogus name for the top-level BCO; this
115 -- should be harmless, since it's never used for anything
116 let invented_id = mkSysLocal SLIT("Expr-Top-Level") (mkPseudoUnique3 0)
117 (panic "invented_id's type")
118 let invented_name = idName invented_id
120 (BcM_State all_proto_bcos final_ctr mallocd, ())
121 <- runBc (BcM_State [] 0 [])
122 (schemeR True (invented_id, freeVars expr))
124 when (not (null mallocd))
125 (panic "ByteCodeGen.coreExprToBCOs: missing final emitBc?")
127 dumpIfSet_dyn dflags Opt_D_dump_BCOs
128 "Proto-bcos" (vcat (intersperse (char ' ') (map ppr all_proto_bcos)))
131 = case filter ((== invented_name).nameOfProtoBCO) all_proto_bcos of
132 [root_bco] -> root_bco
134 = filter ((/= invented_name).nameOfProtoBCO) all_proto_bcos
136 auxiliary_bcos <- mapM assembleBCO auxiliary_proto_bcos
137 root_bco <- assembleBCO root_proto_bco
139 return (root_bco, auxiliary_bcos)
142 %************************************************************************
144 \subsection{Compilation schema for the bytecode generator.}
146 %************************************************************************
150 type BCInstrList = OrdList BCInstr
152 type Sequel = Int -- back off to this depth before ENTER
154 -- Maps Ids to the offset from the stack _base_ so we don't have
155 -- to mess with it after each push/pop.
156 type BCEnv = FiniteMap Id Int -- To find vars on the stack
158 ppBCEnv :: BCEnv -> SDoc
161 $$ nest 4 (vcat (map pp_one (sortBy cmp_snd (fmToList p))))
164 pp_one (var, offset) = int offset <> colon <+> ppr var
165 cmp_snd x y = compare (snd x) (snd y)
167 -- Create a BCO and do a spot of peephole optimisation on the insns
169 mkProtoBCO nm instrs_ordlist origin mallocd_blocks
170 = ProtoBCO nm maybe_with_stack_check origin mallocd_blocks
172 -- Overestimate the stack usage (in words) of this BCO,
173 -- and if >= iNTERP_STACK_CHECK_THRESH, add an explicit
174 -- stack check. (The interpreter always does a stack check
175 -- for iNTERP_STACK_CHECK_THRESH words at the start of each
176 -- BCO anyway, so we only need to add an explicit on in the
177 -- (hopefully rare) cases when the (overestimated) stack use
178 -- exceeds iNTERP_STACK_CHECK_THRESH.
179 maybe_with_stack_check
180 | stack_overest >= 65535
181 = pprPanic "mkProtoBCO: stack use won't fit in 16 bits"
183 | stack_overest >= iNTERP_STACK_CHECK_THRESH
184 = (STKCHECK stack_overest) : peep_d
186 = peep_d -- the supposedly common case
188 stack_overest = sum (map bciStackUse peep_d)
189 + 10 {- just to be really really sure -}
192 -- Merge local pushes
193 peep_d = peep (fromOL instrs_ordlist)
195 peep (PUSH_L off1 : PUSH_L off2 : PUSH_L off3 : rest)
196 = PUSH_LLL off1 (off2-1) (off3-2) : peep rest
197 peep (PUSH_L off1 : PUSH_L off2 : rest)
198 = PUSH_LL off1 (off2-1) : peep rest
205 -- Compile code for the right hand side of a let binding.
206 -- Park the resulting BCO in the monad. Also requires the
207 -- variable to which this value was bound, so as to give the
208 -- resulting BCO a name. Bool indicates top-levelness.
210 schemeR :: Bool -> (Id, AnnExpr Id VarSet) -> BcM ()
211 schemeR is_top (nm, rhs)
215 $$ (ppr.filter (not.isTyVar).varSetElems.fst) rhs
216 $$ pprCoreExpr (deAnnotate rhs)
222 = schemeR_wrk is_top rhs nm (collect [] rhs)
225 collect xs (_, AnnNote note e)
227 collect xs (_, AnnLam x e)
228 = collect (if isTyVar x then xs else (x:xs)) e
229 collect xs not_lambda
230 = (reverse xs, not_lambda)
232 schemeR_wrk is_top original_body nm (args, body)
233 | Just dcon <- maybe_toplevel_null_con_rhs
234 = --trace ("nullary constructor! " ++ showSDocDebug (ppr nm)) (
235 emitBc (mkProtoBCO (getName nm) (toOL [PACK dcon 0, ENTER])
236 (Right original_body))
240 = let fvs = filter (not.isTyVar) (varSetElems (fst original_body))
241 all_args = reverse args ++ fvs
242 szsw_args = map taggedIdSizeW all_args
243 szw_args = sum szsw_args
244 p_init = listToFM (zip all_args (mkStackOffsets 0 szsw_args))
245 argcheck = unitOL (ARGCHECK szw_args)
247 schemeE szw_args 0 p_init body `thenBc` \ body_code ->
248 emitBc (mkProtoBCO (getName nm) (appOL argcheck body_code)
249 (Right original_body))
252 maybe_toplevel_null_con_rhs
253 | is_top && null args
254 = case nukeTyArgs (snd body) of
256 -> case isDataConId_maybe v_wrk of
258 Just dc_wrk | nm == dataConWrapId dc_wrk
266 nukeTyArgs (AnnApp f (_, AnnType _)) = nukeTyArgs (snd f)
267 nukeTyArgs other = other
270 -- Let szsw be the sizes in words of some items pushed onto the stack,
271 -- which has initial depth d'. Return the values which the stack environment
272 -- should map these items to.
273 mkStackOffsets :: Int -> [Int] -> [Int]
274 mkStackOffsets original_depth szsw
275 = map (subtract 1) (tail (scanl (+) original_depth szsw))
277 -- Compile code to apply the given expression to the remaining args
278 -- on the stack, returning a HNF.
279 schemeE :: Int -> Sequel -> BCEnv -> AnnExpr Id VarSet -> BcM BCInstrList
281 -- Delegate tail-calls to schemeT.
282 schemeE d s p e@(fvs, AnnApp f a)
283 = schemeT d s p (fvs, AnnApp f a)
285 schemeE d s p e@(fvs, AnnVar v)
286 | isFollowableRep v_rep
287 = -- Ptr-ish thing; push it in the normal way
288 schemeT d s p (fvs, AnnVar v)
291 = -- returning an unboxed value. Heave it on the stack, SLIDE, and RETURN.
292 pushAtom True d p (AnnVar v) `thenBc` \ (push, szw) ->
293 returnBc (push -- value onto stack
294 `appOL` mkSLIDE szw (d-s) -- clear to sequel
295 `snocOL` RETURN v_rep) -- go
297 v_rep = typePrimRep (idType v)
299 schemeE d s p (fvs, AnnLit literal)
300 = pushAtom True d p (AnnLit literal) `thenBc` \ (push, szw) ->
301 let l_rep = literalPrimRep literal
302 in returnBc (push -- value onto stack
303 `appOL` mkSLIDE szw (d-s) -- clear to sequel
304 `snocOL` RETURN l_rep) -- go
306 schemeE d s p (fvs, AnnLet binds b)
307 = let (xs,rhss) = case binds of AnnNonRec x rhs -> ([x],[rhs])
308 AnnRec xs_n_rhss -> unzip xs_n_rhss
310 fvss = map (filter (not.isTyVar).varSetElems.fst) rhss
312 -- Sizes of tagged free vars, + 1 for the fn
313 sizes = map (\rhs_fvs -> 1 + sum (map taggedIdSizeW rhs_fvs)) fvss
315 -- This p', d' defn is safe because all the items being pushed
316 -- are ptrs, so all have size 1. d' and p' reflect the stack
317 -- after the closures have been allocated in the heap (but not
318 -- filled in), and pointers to them parked on the stack.
319 p' = addListToFM p (zipE xs (mkStackOffsets d (nOfThem n 1)))
322 infos = zipE4 fvss sizes xs [n, n-1 .. 1]
323 zipE = zipEqual "schemeE"
324 zipE4 = zipWith4Equal "schemeE" (\a b c d -> (a,b,c,d))
326 -- ToDo: don't build thunks for things with no free variables
327 buildThunk dd ([], size, id, off)
328 = returnBc (PUSH_G (Left (getName id))
329 `consOL` unitOL (MKAP (off+size-1) size))
330 buildThunk dd ((fv:fvs), size, id, off)
331 = pushAtom True dd p' (AnnVar fv)
332 `thenBc` \ (push_code, pushed_szw) ->
333 buildThunk (dd+pushed_szw) (fvs, size, id, off)
334 `thenBc` \ more_push_code ->
335 returnBc (push_code `appOL` more_push_code)
337 genThunkCode = mapBc (buildThunk d') infos `thenBc` \ tcodes ->
338 returnBc (concatOL tcodes)
340 allocCode = toOL (map ALLOC sizes)
342 schemeE d' s p' b `thenBc` \ bodyCode ->
343 mapBc (schemeR False) (zip xs rhss) `thenBc_`
344 genThunkCode `thenBc` \ thunkCode ->
345 returnBc (allocCode `appOL` thunkCode `appOL` bodyCode)
351 schemeE d s p (fvs_case, AnnCase (fvs_scrut, scrut) bndr
352 [(DEFAULT, [], (fvs_rhs, rhs))])
354 | let isFunType var_type
355 = case splitTyConApp_maybe var_type of
356 Just (tycon,_) | isFunTyCon tycon -> True
358 ty_bndr = repType (idType bndr)
359 in isFunType ty_bndr || isTyVarTy ty_bndr
362 -- case scrut::suspect of bndr { DEFAULT -> rhs }
364 -- let bndr = scrut in rhs
365 -- when suspect is polymorphic or arrowtyped
366 -- So the required strictness properties are not observed.
367 -- At some point, must fix this properly.
371 (AnnNonRec bndr (fvs_scrut, scrut)) (fvs_rhs, rhs)
374 in trace ("WARNING: ignoring polymorphic case in interpreted mode.\n" ++
375 " Possibly due to strict polymorphic/functional constructor args.\n" ++
376 " Your program may leak space unexpectedly.\n")
377 (schemeE d s p new_expr)
381 {- Convert case .... of (# VoidRep'd-thing, a #) -> ...
383 case .... of a -> ...
384 Use a as the name of the binder too.
386 Also case .... of (# a #) -> ...
388 case .... of a -> ...
390 schemeE d s p (fvs, AnnCase scrut bndr [(DataAlt dc, [bind1, bind2], rhs)])
391 | isUnboxedTupleCon dc && VoidRep == typePrimRep (idType bind1)
392 = --trace "automagic mashing of case alts (# VoidRep, a #)" (
393 schemeE d s p (fvs, AnnCase scrut bind2 [(DEFAULT, [bind2], rhs)])
396 schemeE d s p (fvs, AnnCase scrut bndr [(DataAlt dc, [bind1], rhs)])
397 | isUnboxedTupleCon dc
398 = --trace "automagic mashing of case alts (# a #)" (
399 schemeE d s p (fvs, AnnCase scrut bind1 [(DEFAULT, [bind1], rhs)])
402 schemeE d s p (fvs, AnnCase scrut bndr alts)
404 -- Top of stack is the return itbl, as usual.
405 -- underneath it is the pointer to the alt_code BCO.
406 -- When an alt is entered, it assumes the returned value is
407 -- on top of the itbl.
410 -- Env and depth in which to compile the alts, not including
411 -- any vars bound by the alts themselves
412 d' = d + ret_frame_sizeW + taggedIdSizeW bndr
413 p' = addToFM p bndr (d' - 1)
415 scrut_primrep = typePrimRep (idType bndr)
417 | scrut_primrep == PtrRep
419 | scrut_primrep `elem`
420 [CharRep, AddrRep, WordRep, IntRep, FloatRep, DoubleRep,
421 VoidRep, Int8Rep, Int16Rep, Int32Rep, Int64Rep,
422 Word8Rep, Word16Rep, Word32Rep, Word64Rep]
425 = pprPanic "ByteCodeGen.schemeE" (ppr scrut_primrep)
427 -- given an alt, return a discr and code for it.
428 codeAlt alt@(discr, binds_f, rhs)
430 = let (unpack_code, d_after_unpack, p_after_unpack)
431 = mkUnpackCode (filter (not.isTyVar) binds_f) d' p'
432 in schemeE d_after_unpack s p_after_unpack rhs
433 `thenBc` \ rhs_code ->
434 returnBc (my_discr alt, unpack_code `appOL` rhs_code)
436 = ASSERT(null binds_f)
437 schemeE d' s p' rhs `thenBc` \ rhs_code ->
438 returnBc (my_discr alt, rhs_code)
440 my_discr (DEFAULT, binds, rhs) = NoDiscr
441 my_discr (DataAlt dc, binds, rhs)
442 | isUnboxedTupleCon dc
443 = unboxedTupleException
445 = DiscrP (dataConTag dc - fIRST_TAG)
446 my_discr (LitAlt l, binds, rhs)
447 = case l of MachInt i -> DiscrI (fromInteger i)
448 MachFloat r -> DiscrF (fromRational r)
449 MachDouble r -> DiscrD (fromRational r)
450 MachChar i -> DiscrI i
451 _ -> pprPanic "schemeE(AnnCase).my_discr" (ppr l)
454 | not isAlgCase = Nothing
456 = case [dc | (DataAlt dc, _, _) <- alts] of
458 (dc:_) -> Just (tyConFamilySize (dataConTyCon dc))
461 mapBc codeAlt alts `thenBc` \ alt_stuff ->
462 mkMultiBranch maybe_ncons alt_stuff `thenBc` \ alt_final ->
464 alt_final_ac = ARGCHECK (taggedIdSizeW bndr) `consOL` alt_final
465 alt_bco_name = getName bndr
466 alt_bco = mkProtoBCO alt_bco_name alt_final_ac (Left alts)
468 schemeE (d + ret_frame_sizeW)
469 (d + ret_frame_sizeW) p scrut `thenBc` \ scrut_code ->
471 emitBc alt_bco `thenBc_`
472 returnBc (PUSH_AS alt_bco_name scrut_primrep `consOL` scrut_code)
475 schemeE d s p (fvs, AnnNote note body)
479 = pprPanic "ByteCodeGen.schemeE: unhandled case"
480 (pprCoreExpr (deAnnotate other))
483 -- Compile code to do a tail call. Specifically, push the fn,
484 -- slide the on-stack app back down to the sequel depth,
485 -- and enter. Four cases:
488 -- An application "PrelGHC.tagToEnum# <type> unboxed-int".
489 -- The int will be on the stack. Generate a code sequence
490 -- to convert it to the relevant constructor, SLIDE and ENTER.
492 -- 1. A nullary constructor. Push its closure on the stack
493 -- and SLIDE and RETURN.
495 -- 2. (Another nasty hack). Spot (# a::VoidRep, b #) and treat
496 -- it simply as b -- since the representations are identical
497 -- (the VoidRep takes up zero stack space). Also, spot
498 -- (# b #) and treat it as b.
500 -- 3. The fn denotes a ccall. Defer to generateCCall.
502 -- 4. Application of a non-nullary constructor, by defn saturated.
503 -- Split the args into ptrs and non-ptrs, and push the nonptrs,
504 -- then the ptrs, and then do PACK and RETURN.
506 -- 5. Otherwise, it must be a function call. Push the args
507 -- right to left, SLIDE and ENTER.
509 schemeT :: Int -- Stack depth
510 -> Sequel -- Sequel depth
511 -> BCEnv -- stack env
517 -- | trace ("schemeT: env in = \n" ++ showSDocDebug (ppBCEnv p)) False
518 -- = panic "schemeT ?!?!"
520 -- | trace ("\nschemeT\n" ++ showSDoc (pprCoreExpr (deAnnotate app)) ++ "\n") False
524 | Just (arg, constr_names) <- maybe_is_tagToEnum_call
525 = pushAtom True d p arg `thenBc` \ (push, arg_words) ->
526 implement_tagToId constr_names `thenBc` \ tagToId_sequence ->
527 returnBc (push `appOL` tagToId_sequence
528 `appOL` mkSLIDE 1 (d+arg_words-s)
532 | is_con_call && null args_r_to_l
534 (PUSH_G (Left (getName con)) `consOL` mkSLIDE 1 (d-s))
539 | let isVoidRepAtom (_, AnnVar v) = VoidRep == typePrimRep (idType v)
540 isVoidRepAtom (_, AnnNote n e) = isVoidRepAtom e
541 in is_con_call && isUnboxedTupleCon con
542 && ( (args_r_to_l `lengthIs` 2 && isVoidRepAtom (last (args_r_to_l)))
543 || (isSingleton args_r_to_l)
545 = --trace (if isSingleton args_r_to_l
546 -- then "schemeT: unboxed singleton"
547 -- else "schemeT: unboxed pair with Void first component") (
548 schemeT d s p (head args_r_to_l)
552 | Just (CCall ccall_spec) <- isFCallId_maybe fn
553 = generateCCall d s p ccall_spec fn args_r_to_l
557 = if is_con_call && isUnboxedTupleCon con
558 then unboxedTupleException
559 else do_pushery d (map snd args_final_r_to_l)
562 -- Detect and extract relevant info for the tagToEnum kludge.
563 maybe_is_tagToEnum_call
564 = let extract_constr_Names ty
565 = case splitTyConApp_maybe (repType ty) of
566 (Just (tyc, [])) | isDataTyCon tyc
567 -> map getName (tyConDataCons tyc)
568 other -> panic "maybe_is_tagToEnum_call.extract_constr_Ids"
571 (_, AnnApp (_, AnnApp (_, AnnVar v) (_, AnnType t)) arg)
572 -> case isPrimOpId_maybe v of
573 Just TagToEnumOp -> Just (snd arg, extract_constr_Names t)
577 -- Extract the args (R->L) and fn
578 (args_r_to_l_raw, fn) = chomp app
582 AnnApp f a -> case chomp f of (az, f) -> (a:az, f)
583 AnnNote n e -> chomp e
584 other -> pprPanic "schemeT"
585 (ppr (deAnnotate (panic "schemeT.chomp", other)))
587 args_r_to_l = filter (not.isTypeAtom.snd) args_r_to_l_raw
588 isTypeAtom (AnnType _) = True
591 -- decide if this is a constructor call, and rearrange
592 -- args appropriately.
593 maybe_dcon = isDataConId_maybe fn
594 is_con_call = case maybe_dcon of Nothing -> False; Just _ -> True
595 (Just con) = maybe_dcon
601 = filter (not.isPtr.snd) args_r_to_l ++ filter (isPtr.snd) args_r_to_l
602 where isPtr = isFollowableRep . atomRep
604 -- make code to push the args and then do the SLIDE-ENTER thing
605 tag_when_push = not is_con_call
606 narg_words = sum (map (get_arg_szw . atomRep . snd) args_r_to_l)
607 get_arg_szw = if tag_when_push then taggedSizeW else untaggedSizeW
609 do_pushery d (arg:args)
610 = pushAtom tag_when_push d p arg `thenBc` \ (push, arg_words) ->
611 do_pushery (d+arg_words) args `thenBc` \ more_push_code ->
612 returnBc (push `appOL` more_push_code)
614 | Just (CCall ccall_spec) <- isFCallId_maybe fn
615 = panic "schemeT.do_pushery: unexpected ccall"
618 Just con -> returnBc (
619 (PACK con narg_words `consOL`
620 mkSLIDE 1 (d - narg_words - s)) `snocOL`
624 -> pushAtom True d p (AnnVar fn)
625 `thenBc` \ (push, arg_words) ->
626 returnBc (push `appOL` mkSLIDE (narg_words+arg_words)
632 {- Deal with a CCall. Taggedly push the args onto the stack R->L,
633 deferencing ForeignObj#s and (ToDo: adjusting addrs to point to
634 payloads in Ptr/Byte arrays). Then, generate the marshalling
635 (machine) code for the ccall, and create bytecodes to call that and
636 then return in the right way.
638 generateCCall :: Int -> Sequel -- stack and sequel depths
640 -> CCallSpec -- where to call
641 -> Id -- of target, for type info
642 -> [AnnExpr Id VarSet] -- args (atoms)
645 generateCCall d0 s p ccall_spec@(CCallSpec target cconv safety) fn args_r_to_l
648 addr_usizeW = untaggedSizeW AddrRep
649 addr_tsizeW = taggedSizeW AddrRep
651 -- Get the args on the stack, with tags and suitably
652 -- dereferenced for the CCall. For each arg, return the
653 -- depth to the first word of the bits for that arg, and the
654 -- PrimRep of what was actually pushed.
656 pargs d [] = returnBc []
658 = let rep_arg = atomRep a
660 -- Don't push the FO; instead push the Addr# it
663 -> pushAtom False{-irrelevant-} d p a
664 `thenBc` \ (push_fo, _) ->
665 let foro_szW = taggedSizeW ForeignObjRep
666 d_now = d + addr_tsizeW
667 code = push_fo `appOL` toOL [
668 UPK_TAG addr_usizeW 0 0,
669 SLIDE addr_tsizeW foro_szW
671 in pargs d_now az `thenBc` \ rest ->
672 returnBc ((code, AddrRep) : rest)
675 -> pargs (d + addr_tsizeW) az `thenBc` \ rest ->
676 parg_ArrayishRep arrPtrsHdrSize d p a
678 returnBc ((code,AddrRep):rest)
681 -> pargs (d + addr_tsizeW) az `thenBc` \ rest ->
682 parg_ArrayishRep arrWordsHdrSize d p a
684 returnBc ((code,AddrRep):rest)
686 -- Default case: push taggedly, but otherwise intact.
688 -> pushAtom True d p a `thenBc` \ (code_a, sz_a) ->
689 pargs (d+sz_a) az `thenBc` \ rest ->
690 returnBc ((code_a, rep_arg) : rest)
692 -- Do magic for Ptr/Byte arrays. Push a ptr to the array on
693 -- the stack but then advance it over the headers, so as to
694 -- point to the payload.
695 parg_ArrayishRep hdrSizeW d p a
696 = pushAtom False{-irrel-} d p a `thenBc` \ (push_fo, _) ->
697 -- The ptr points at the header. Advance it over the
698 -- header and then pretend this is an Addr# (push a tag).
699 returnBc (push_fo `snocOL`
700 SWIZZLE 0 (hdrSizeW * untaggedSizeW PtrRep
703 PUSH_TAG addr_usizeW)
706 pargs d0 args_r_to_l `thenBc` \ code_n_reps ->
708 (pushs_arg, a_reps_pushed_r_to_l) = unzip code_n_reps
710 push_args = concatOL pushs_arg
711 d_after_args = d0 + sum (map taggedSizeW a_reps_pushed_r_to_l)
713 | null a_reps_pushed_r_to_l || head a_reps_pushed_r_to_l /= VoidRep
714 = panic "ByteCodeGen.generateCCall: missing or invalid World token?"
716 = reverse (tail a_reps_pushed_r_to_l)
718 -- Now: a_reps_pushed_RAW are the reps which are actually on the stack.
719 -- push_args is the code to do that.
720 -- d_after_args is the stack depth once the args are on.
722 -- Get the result rep.
723 (returns_void, r_rep)
724 = case maybe_getCCallReturnRep (idType fn) of
725 Nothing -> (True, VoidRep)
726 Just rr -> (False, rr)
728 Because the Haskell stack grows down, the a_reps refer to
729 lowest to highest addresses in that order. The args for the call
730 are on the stack. Now push an unboxed, tagged Addr# indicating
731 the C function to call. Then push a dummy placeholder for the
732 result. Finally, emit a CCALL insn with an offset pointing to the
733 Addr# just pushed, and a literal field holding the mallocville
734 address of the piece of marshalling code we generate.
735 So, just prior to the CCALL insn, the stack looks like this
736 (growing down, as usual):
741 Addr# address_of_C_fn
742 <placeholder-for-result#> (must be an unboxed type)
744 The interpreter then calls the marshall code mentioned
745 in the CCALL insn, passing it (& <placeholder-for-result#>),
746 that is, the addr of the topmost word in the stack.
747 When this returns, the placeholder will have been
748 filled in. The placeholder is slid down to the sequel
749 depth, and we RETURN.
751 This arrangement makes it simple to do f-i-dynamic since the Addr#
752 value is the first arg anyway. It also has the virtue that the
753 stack is GC-understandable at all times.
755 The marshalling code is generated specifically for this
756 call site, and so knows exactly the (Haskell) stack
757 offsets of the args, fn address and placeholder. It
758 copies the args to the C stack, calls the stacked addr,
759 and parks the result back in the placeholder. The interpreter
760 calls it as a normal C call, assuming it has a signature
761 void marshall_code ( StgWord* ptr_to_top_of_stack )
763 -- resolve static address
767 -> returnBc (False, panic "ByteCodeGen.generateCCall(dyn)")
769 -> let sym_to_find = _UNPK_ target in
770 ioToBc (lookupSymbol sym_to_find) `thenBc` \res ->
772 Just aa -> case aa of Ptr a# -> returnBc (True, A# a#)
773 Nothing -> ioToBc (linkFail "ByteCodeGen.generateCCall"
776 -> pprPanic "ByteCodeGen.generateCCall: casm" (ppr ccall_spec)
778 get_target_info `thenBc` \ (is_static, static_target_addr) ->
781 -- Get the arg reps, zapping the leading Addr# in the dynamic case
782 a_reps -- | trace (showSDoc (ppr a_reps_pushed_RAW)) False = error "???"
783 | is_static = a_reps_pushed_RAW
784 | otherwise = if null a_reps_pushed_RAW
785 then panic "ByteCodeGen.generateCCall: dyn with no args"
786 else tail a_reps_pushed_RAW
789 (push_Addr, d_after_Addr)
791 = (toOL [PUSH_UBX (Right static_target_addr) addr_usizeW,
792 PUSH_TAG addr_usizeW],
793 d_after_args + addr_tsizeW)
794 | otherwise -- is already on the stack
795 = (nilOL, d_after_args)
797 -- Push the return placeholder. For a call returning nothing,
798 -- this is a VoidRep (tag).
799 r_usizeW = untaggedSizeW r_rep
800 r_tsizeW = taggedSizeW r_rep
801 d_after_r = d_after_Addr + r_tsizeW
802 r_lit = mkDummyLiteral r_rep
803 push_r = (if returns_void
805 else unitOL (PUSH_UBX (Left r_lit) r_usizeW))
807 unitOL (PUSH_TAG r_usizeW)
809 -- generate the marshalling code we're going to call
812 arg1_offW = r_tsizeW + addr_tsizeW
813 args_offW = map (arg1_offW +)
814 (init (scanl (+) 0 (map taggedSizeW a_reps)))
816 ioToBc (mkMarshalCode cconv
817 (r_offW, r_rep) addr_offW
818 (zip args_offW a_reps)) `thenBc` \ addr_of_marshaller ->
819 recordMallocBc addr_of_marshaller `thenBc_`
822 do_call = unitOL (CCALL addr_of_marshaller)
824 wrapup = mkSLIDE r_tsizeW (d_after_r - r_tsizeW - s)
825 `snocOL` RETURN r_rep
827 --trace (show (arg1_offW, args_offW , (map taggedSizeW a_reps) )) (
830 push_Addr `appOL` push_r `appOL` do_call `appOL` wrapup
835 -- Make a dummy literal, to be used as a placeholder for FFI return
836 -- values on the stack.
837 mkDummyLiteral :: PrimRep -> Literal
840 CharRep -> MachChar 0
842 WordRep -> MachWord 0
843 DoubleRep -> MachDouble 0
844 FloatRep -> MachFloat 0
845 AddrRep | taggedSizeW AddrRep == taggedSizeW WordRep -> MachWord 0
846 _ -> moan64 "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 isSingleton r_reps 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 = ( ( r_reps `lengthIs` 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 = moan64 "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])