2 % (c) The University of Glasgow 2002-2006
5 ByteCodeGen: Generate bytecode from Core
8 module ByteCodeGen ( UnlinkedBCO, byteCodeGen, coreExprToBCOs ) where
10 #include "HsVersions.h"
54 -- import GHC.Exts ( Int(..) )
56 import Control.Monad ( when )
65 -- -----------------------------------------------------------------------------
66 -- Generating byte code for a complete module
68 byteCodeGen :: DynFlags
72 -> IO CompiledByteCode
73 byteCodeGen dflags binds tycs modBreaks
74 = do showPass dflags "ByteCodeGen"
76 let flatBinds = [ (bndr, freeVars rhs)
77 | (bndr, rhs) <- flattenBinds binds]
79 us <- mkSplitUniqSupply 'y'
80 (BcM_State _us _final_ctr mallocd _, proto_bcos)
81 <- runBc us modBreaks (mapM schemeTopBind flatBinds)
83 when (notNull mallocd)
84 (panic "ByteCodeGen.byteCodeGen: missing final emitBc?")
86 dumpIfSet_dyn dflags Opt_D_dump_BCOs
87 "Proto-BCOs" (vcat (intersperse (char ' ') (map ppr proto_bcos)))
89 assembleBCOs proto_bcos tycs
91 -- -----------------------------------------------------------------------------
92 -- Generating byte code for an expression
94 -- Returns: (the root BCO for this expression,
95 -- a list of auxilary BCOs resulting from compiling closures)
96 coreExprToBCOs :: DynFlags
99 coreExprToBCOs dflags expr
100 = do showPass dflags "ByteCodeGen"
102 -- create a totally bogus name for the top-level BCO; this
103 -- should be harmless, since it's never used for anything
104 let invented_name = mkSystemVarName (mkPseudoUniqueE 0) (fsLit "ExprTopLevel")
105 invented_id = Id.mkLocalId invented_name (panic "invented_id's type")
107 -- the uniques are needed to generate fresh variables when we introduce new
108 -- let bindings for ticked expressions
109 us <- mkSplitUniqSupply 'y'
110 (BcM_State _us _final_ctr mallocd _ , proto_bco)
111 <- runBc us emptyModBreaks (schemeTopBind (invented_id, freeVars expr))
113 when (notNull mallocd)
114 (panic "ByteCodeGen.coreExprToBCOs: missing final emitBc?")
116 dumpIfSet_dyn dflags Opt_D_dump_BCOs "Proto-BCOs" (ppr proto_bco)
118 assembleBCO proto_bco
121 -- -----------------------------------------------------------------------------
122 -- Compilation schema for the bytecode generator
124 type BCInstrList = OrdList BCInstr
126 type Sequel = Word16 -- back off to this depth before ENTER
128 -- Maps Ids to the offset from the stack _base_ so we don't have
129 -- to mess with it after each push/pop.
130 type BCEnv = FiniteMap Id Word16 -- To find vars on the stack
133 ppBCEnv :: BCEnv -> SDoc
136 $$ nest 4 (vcat (map pp_one (sortBy cmp_snd (fmToList p))))
139 pp_one (var, offset) = int offset <> colon <+> ppr var <+> ppr (idCgRep var)
140 cmp_snd x y = compare (snd x) (snd y)
143 -- Create a BCO and do a spot of peephole optimisation on the insns
148 -> Either [AnnAlt Id VarSet] (AnnExpr Id VarSet)
152 -> Bool -- True <=> is a return point, rather than a function
155 mkProtoBCO nm instrs_ordlist origin arity bitmap_size bitmap is_ret mallocd_blocks
158 protoBCOInstrs = maybe_with_stack_check,
159 protoBCOBitmap = bitmap,
160 protoBCOBitmapSize = bitmap_size,
161 protoBCOArity = arity,
162 protoBCOExpr = origin,
163 protoBCOPtrs = mallocd_blocks
166 -- Overestimate the stack usage (in words) of this BCO,
167 -- and if >= iNTERP_STACK_CHECK_THRESH, add an explicit
168 -- stack check. (The interpreter always does a stack check
169 -- for iNTERP_STACK_CHECK_THRESH words at the start of each
170 -- BCO anyway, so we only need to add an explicit one in the
171 -- (hopefully rare) cases when the (overestimated) stack use
172 -- exceeds iNTERP_STACK_CHECK_THRESH.
173 maybe_with_stack_check
174 | is_ret && stack_usage < fromIntegral aP_STACK_SPLIM = peep_d
175 -- don't do stack checks at return points,
176 -- everything is aggregated up to the top BCO
177 -- (which must be a function).
178 -- That is, unless the stack usage is >= AP_STACK_SPLIM,
180 | stack_usage >= fromIntegral iNTERP_STACK_CHECK_THRESH
181 = STKCHECK stack_usage : peep_d
183 = peep_d -- the supposedly common case
185 -- We assume that this sum doesn't wrap
186 stack_usage = sum (map bciStackUse peep_d)
188 -- Merge local pushes
189 peep_d = peep (fromOL instrs_ordlist)
191 peep (PUSH_L off1 : PUSH_L off2 : PUSH_L off3 : rest)
192 = PUSH_LLL off1 (off2-1) (off3-2) : peep rest
193 peep (PUSH_L off1 : PUSH_L off2 : rest)
194 = PUSH_LL off1 (off2-1) : peep rest
200 argBits :: [CgRep] -> [Bool]
203 | isFollowableArg rep = False : argBits args
204 | otherwise = take (cgRepSizeW rep) (repeat True) ++ argBits args
206 -- -----------------------------------------------------------------------------
209 -- Compile code for the right-hand side of a top-level binding
211 schemeTopBind :: (Id, AnnExpr Id VarSet) -> BcM (ProtoBCO Name)
214 schemeTopBind (id, rhs)
215 | Just data_con <- isDataConWorkId_maybe id,
216 isNullaryRepDataCon data_con = do
217 -- Special case for the worker of a nullary data con.
218 -- It'll look like this: Nil = /\a -> Nil a
219 -- If we feed it into schemeR, we'll get
221 -- because mkConAppCode treats nullary constructor applications
222 -- by just re-using the single top-level definition. So
223 -- for the worker itself, we must allocate it directly.
224 -- ioToBc (putStrLn $ "top level BCO")
225 emitBc (mkProtoBCO (getName id) (toOL [PACK data_con 0, ENTER])
226 (Right rhs) 0 0 [{-no bitmap-}] False{-not alts-})
229 = schemeR [{- No free variables -}] (id, rhs)
232 -- -----------------------------------------------------------------------------
235 -- Compile code for a right-hand side, to give a BCO that,
236 -- when executed with the free variables and arguments on top of the stack,
237 -- will return with a pointer to the result on top of the stack, after
238 -- removing the free variables and arguments.
240 -- Park the resulting BCO in the monad. Also requires the
241 -- variable to which this value was bound, so as to give the
242 -- resulting BCO a name.
244 schemeR :: [Id] -- Free vars of the RHS, ordered as they
245 -- will appear in the thunk. Empty for
246 -- top-level things, which have no free vars.
247 -> (Id, AnnExpr Id VarSet)
248 -> BcM (ProtoBCO Name)
249 schemeR fvs (nm, rhs)
253 $$ (ppr.filter (not.isTyVar).varSetElems.fst) rhs
254 $$ pprCoreExpr (deAnnotate rhs)
260 = schemeR_wrk fvs nm rhs (collect rhs)
262 collect :: AnnExpr Id VarSet -> ([Var], AnnExpr' Id VarSet)
263 collect (_, e) = go [] e
265 go xs e | Just e' <- bcView e = go xs e'
266 go xs (AnnLam x (_,e)) = go (x:xs) e
267 go xs not_lambda = (reverse xs, not_lambda)
269 schemeR_wrk :: [Id] -> Id -> AnnExpr Id VarSet -> ([Var], AnnExpr' Var VarSet) -> BcM (ProtoBCO Name)
270 schemeR_wrk fvs nm original_body (args, body)
272 all_args = reverse args ++ fvs
273 arity = length all_args
274 -- all_args are the args in reverse order. We're compiling a function
275 -- \fv1..fvn x1..xn -> e
276 -- i.e. the fvs come first
278 szsw_args = map (fromIntegral . idSizeW) all_args
279 szw_args = sum szsw_args
280 p_init = listToFM (zip all_args (mkStackOffsets 0 szsw_args))
282 -- make the arg bitmap
283 bits = argBits (reverse (map idCgRep all_args))
284 bitmap_size = genericLength bits
285 bitmap = mkBitmap bits
287 body_code <- schemeER_wrk szw_args p_init body
289 emitBc (mkProtoBCO (getName nm) body_code (Right original_body)
290 arity bitmap_size bitmap False{-not alts-})
292 -- introduce break instructions for ticked expressions
293 schemeER_wrk :: Word16 -> BCEnv -> AnnExpr' Id VarSet -> BcM BCInstrList
295 | Just (tickInfo, (_annot, newRhs)) <- isTickedExp' rhs = do
296 code <- schemeE d 0 p newRhs
298 let idOffSets = getVarOffSets (fromIntegral d) p tickInfo
299 let tickNumber = tickInfo_number tickInfo
300 let breakInfo = BreakInfo
301 { breakInfo_module = tickInfo_module tickInfo
302 , breakInfo_number = tickNumber
303 , breakInfo_vars = idOffSets
304 , breakInfo_resty = exprType (deAnnotate' newRhs)
306 let breakInstr = case arr of
308 BRK_FUN arr# (fromIntegral tickNumber) breakInfo
309 return $ breakInstr `consOL` code
310 | otherwise = schemeE d 0 p rhs
312 getVarOffSets :: Word16 -> BCEnv -> TickInfo -> [(Id, Word16)]
313 getVarOffSets d p = catMaybes . map (getOffSet d p) . tickInfo_locals
315 getOffSet :: Word16 -> BCEnv -> Id -> Maybe (Id, Word16)
317 = case lookupBCEnv_maybe env id of
319 Just offset -> Just (id, d - offset)
321 fvsToEnv :: BCEnv -> VarSet -> [Id]
322 -- Takes the free variables of a right-hand side, and
323 -- delivers an ordered list of the local variables that will
324 -- be captured in the thunk for the RHS
325 -- The BCEnv argument tells which variables are in the local
326 -- environment: these are the ones that should be captured
328 -- The code that constructs the thunk, and the code that executes
329 -- it, have to agree about this layout
330 fvsToEnv p fvs = [v | v <- varSetElems fvs,
331 isId v, -- Could be a type variable
334 -- -----------------------------------------------------------------------------
339 { tickInfo_number :: Int -- the (module) unique number of the tick
340 , tickInfo_module :: Module -- the origin of the ticked expression
341 , tickInfo_locals :: [Id] -- the local vars in scope at the ticked expression
344 instance Outputable TickInfo where
345 ppr info = text "TickInfo" <+>
346 parens (int (tickInfo_number info) <+> ppr (tickInfo_module info) <+>
347 ppr (tickInfo_locals info))
349 -- Compile code to apply the given expression to the remaining args
350 -- on the stack, returning a HNF.
351 schemeE :: Word16 -> Sequel -> BCEnv -> AnnExpr' Id VarSet -> BcM BCInstrList
354 | Just e' <- bcView e
357 -- Delegate tail-calls to schemeT.
358 schemeE d s p e@(AnnApp _ _)
361 schemeE d s p e@(AnnVar v)
362 | not (isUnLiftedType v_type)
363 = -- Lifted-type thing; push it in the normal way
367 = do -- Returning an unlifted value.
368 -- Heave it on the stack, SLIDE, and RETURN.
369 (push, szw) <- pushAtom d p (AnnVar v)
370 return (push -- value onto stack
371 `appOL` mkSLIDE szw (d-s) -- clear to sequel
372 `snocOL` RETURN_UBX v_rep) -- go
375 v_rep = typeCgRep v_type
377 schemeE d s p (AnnLit literal)
378 = do (push, szw) <- pushAtom d p (AnnLit literal)
379 let l_rep = typeCgRep (literalType literal)
380 return (push -- value onto stack
381 `appOL` mkSLIDE szw (d-s) -- clear to sequel
382 `snocOL` RETURN_UBX l_rep) -- go
384 schemeE d s p (AnnLet (AnnNonRec x (_,rhs)) (_,body))
385 | (AnnVar v, args_r_to_l) <- splitApp rhs,
386 Just data_con <- isDataConWorkId_maybe v,
387 dataConRepArity data_con == length args_r_to_l
388 = do -- Special case for a non-recursive let whose RHS is a
389 -- saturatred constructor application.
390 -- Just allocate the constructor and carry on
391 alloc_code <- mkConAppCode d s p data_con args_r_to_l
392 body_code <- schemeE (d+1) s (addToFM p x d) body
393 return (alloc_code `appOL` body_code)
395 -- General case for let. Generates correct, if inefficient, code in
397 schemeE d s p (AnnLet binds (_,body))
398 = let (xs,rhss) = case binds of AnnNonRec x rhs -> ([x],[rhs])
399 AnnRec xs_n_rhss -> unzip xs_n_rhss
400 n_binds = genericLength xs
402 fvss = map (fvsToEnv p' . fst) rhss
404 -- Sizes of free vars
405 sizes = map (\rhs_fvs -> sum (map (fromIntegral . idSizeW) rhs_fvs)) fvss
407 -- the arity of each rhs
408 arities = map (genericLength . fst . collect) rhss
410 -- This p', d' defn is safe because all the items being pushed
411 -- are ptrs, so all have size 1. d' and p' reflect the stack
412 -- after the closures have been allocated in the heap (but not
413 -- filled in), and pointers to them parked on the stack.
414 p' = addListToFM p (zipE xs (mkStackOffsets d (genericReplicate n_binds 1)))
416 zipE = zipEqual "schemeE"
418 -- ToDo: don't build thunks for things with no free variables
419 build_thunk _ [] size bco off arity
420 = return (PUSH_BCO bco `consOL` unitOL (mkap (off+size) size))
422 mkap | arity == 0 = MKAP
424 build_thunk dd (fv:fvs) size bco off arity = do
425 (push_code, pushed_szw) <- pushAtom dd p' (AnnVar fv)
426 more_push_code <- build_thunk (dd+pushed_szw) fvs size bco off arity
427 return (push_code `appOL` more_push_code)
429 alloc_code = toOL (zipWith mkAlloc sizes arities)
431 | is_tick = ALLOC_AP_NOUPD sz
432 | otherwise = ALLOC_AP sz
433 mkAlloc sz arity = ALLOC_PAP arity sz
435 is_tick = case binds of
436 AnnNonRec id _ -> occNameFS (getOccName id) == tickFS
439 compile_bind d' fvs x rhs size arity off = do
440 bco <- schemeR fvs (x,rhs)
441 build_thunk d' fvs size bco off arity
444 [ compile_bind d' fvs x rhs size arity n
445 | (fvs, x, rhs, size, arity, n) <-
446 zip6 fvss xs rhss sizes arities [n_binds, n_binds-1 .. 1]
449 body_code <- schemeE d' s p' body
450 thunk_codes <- sequence compile_binds
451 return (alloc_code `appOL` concatOL thunk_codes `appOL` body_code)
453 -- introduce a let binding for a ticked case expression. This rule
454 -- *should* only fire when the expression was not already let-bound
455 -- (the code gen for let bindings should take care of that). Todo: we
456 -- call exprFreeVars on a deAnnotated expression, this may not be the
457 -- best way to calculate the free vars but it seemed like the least
458 -- intrusive thing to do
459 schemeE d s p exp@(AnnCase {})
460 | Just (_tickInfo, _rhs) <- isTickedExp' exp
461 = if isUnLiftedType ty
463 -- If the result type is unlifted, then we must generate
464 -- let f = \s . case tick# of _ -> e
466 -- When we stop at the breakpoint, _result will have an unlifted
467 -- type and hence won't be bound in the environment, but the
468 -- breakpoint will otherwise work fine.
469 id <- newId (mkFunTy realWorldStatePrimTy ty)
470 st <- newId realWorldStatePrimTy
471 let letExp = AnnLet (AnnNonRec id (fvs, AnnLam st (emptyVarSet, exp)))
472 (emptyVarSet, (AnnApp (emptyVarSet, AnnVar id)
473 (emptyVarSet, AnnVar realWorldPrimId)))
477 -- Todo: is emptyVarSet correct on the next line?
478 let letExp = AnnLet (AnnNonRec id (fvs, exp)) (emptyVarSet, AnnVar id)
480 where exp' = deAnnotate' exp
481 fvs = exprFreeVars exp'
484 schemeE d s p (AnnCase scrut _ _ [(DataAlt dc, [bind1, bind2], rhs)])
485 | isUnboxedTupleCon dc, VoidArg <- typeCgRep (idType bind1)
487 -- case .... of x { (# VoidArg'd-thing, a #) -> ... }
489 -- case .... of a { DEFAULT -> ... }
490 -- becuse the return convention for both are identical.
492 -- Note that it does not matter losing the void-rep thing from the
493 -- envt (it won't be bound now) because we never look such things up.
495 = --trace "automagic mashing of case alts (# VoidArg, a #)" $
496 doCase d s p scrut bind2 [(DEFAULT, [], rhs)] True{-unboxed tuple-}
498 | isUnboxedTupleCon dc, VoidArg <- typeCgRep (idType bind2)
499 = --trace "automagic mashing of case alts (# a, VoidArg #)" $
500 doCase d s p scrut bind1 [(DEFAULT, [], rhs)] True{-unboxed tuple-}
502 schemeE d s p (AnnCase scrut _ _ [(DataAlt dc, [bind1], rhs)])
503 | isUnboxedTupleCon dc
504 -- Similarly, convert
505 -- case .... of x { (# a #) -> ... }
507 -- case .... of a { DEFAULT -> ... }
508 = --trace "automagic mashing of case alts (# a #)" $
509 doCase d s p scrut bind1 [(DEFAULT, [], rhs)] True{-unboxed tuple-}
511 schemeE d s p (AnnCase scrut bndr _ alts)
512 = doCase d s p scrut bndr alts False{-not an unboxed tuple-}
515 = pprPanic "ByteCodeGen.schemeE: unhandled case"
516 (pprCoreExpr (deAnnotate' expr))
522 A ticked expression looks like this:
524 case tick<n> var1 ... varN of DEFAULT -> e
526 (*) <n> is the number of the tick, which is unique within a module
527 (*) var1 ... varN are the local variables in scope at the tick site
529 If we find a ticked expression we return:
531 Just ((n, [var1 ... varN]), e)
533 otherwise we return Nothing.
535 The idea is that the "case tick<n> ..." is really just an annotation on
536 the code. When we find such a thing, we pull out the useful information,
537 and then compile the code as if it was just the expression "e".
541 isTickedExp' :: AnnExpr' Id a -> Maybe (TickInfo, AnnExpr Id a)
542 isTickedExp' (AnnCase scrut _bndr _type alts)
543 | Just tickInfo <- isTickedScrut scrut,
544 [(DEFAULT, _bndr, rhs)] <- alts
545 = Just (tickInfo, rhs)
547 isTickedScrut :: (AnnExpr Id a) -> Maybe TickInfo
550 Just (TickBox modName tickNumber) <- isTickBoxOp_maybe id
551 = Just $ TickInfo { tickInfo_number = tickNumber
552 , tickInfo_module = modName
553 , tickInfo_locals = idsOfArgs args
555 | otherwise = Nothing
557 (f, args) = collectArgs $ deAnnotate expr
558 idsOfArgs :: [Expr Id] -> [Id]
559 idsOfArgs = catMaybes . map exprId
560 exprId :: Expr Id -> Maybe Id
561 exprId (Var id) = Just id
564 isTickedExp' _ = Nothing
566 -- Compile code to do a tail call. Specifically, push the fn,
567 -- slide the on-stack app back down to the sequel depth,
568 -- and enter. Four cases:
571 -- An application "GHC.Prim.tagToEnum# <type> unboxed-int".
572 -- The int will be on the stack. Generate a code sequence
573 -- to convert it to the relevant constructor, SLIDE and ENTER.
575 -- 1. The fn denotes a ccall. Defer to generateCCall.
577 -- 2. (Another nasty hack). Spot (# a::VoidArg, b #) and treat
578 -- it simply as b -- since the representations are identical
579 -- (the VoidArg takes up zero stack space). Also, spot
580 -- (# b #) and treat it as b.
582 -- 3. Application of a constructor, by defn saturated.
583 -- Split the args into ptrs and non-ptrs, and push the nonptrs,
584 -- then the ptrs, and then do PACK and RETURN.
586 -- 4. Otherwise, it must be a function call. Push the args
587 -- right to left, SLIDE and ENTER.
589 schemeT :: Word16 -- Stack depth
590 -> Sequel -- Sequel depth
591 -> BCEnv -- stack env
592 -> AnnExpr' Id VarSet
597 -- | trace ("schemeT: env in = \n" ++ showSDocDebug (ppBCEnv p)) False
598 -- = panic "schemeT ?!?!"
600 -- | trace ("\nschemeT\n" ++ showSDoc (pprCoreExpr (deAnnotate' app)) ++ "\n") False
604 | Just (arg, constr_names) <- maybe_is_tagToEnum_call
605 = do (push, arg_words) <- pushAtom d p arg
606 tagToId_sequence <- implement_tagToId constr_names
607 return (push `appOL` tagToId_sequence
608 `appOL` mkSLIDE 1 (d+arg_words-s)
612 | Just (CCall ccall_spec) <- isFCallId_maybe fn
613 = generateCCall d s p ccall_spec fn args_r_to_l
615 -- Case 2: Constructor application
616 | Just con <- maybe_saturated_dcon,
617 isUnboxedTupleCon con
618 = case args_r_to_l of
619 [arg1,arg2] | isVoidArgAtom arg1 ->
620 unboxedTupleReturn d s p arg2
621 [arg1,arg2] | isVoidArgAtom arg2 ->
622 unboxedTupleReturn d s p arg1
623 _other -> unboxedTupleException
625 -- Case 3: Ordinary data constructor
626 | Just con <- maybe_saturated_dcon
627 = do alloc_con <- mkConAppCode d s p con args_r_to_l
628 return (alloc_con `appOL`
629 mkSLIDE 1 (d - s) `snocOL`
632 -- Case 4: Tail call of function
634 = doTailCall d s p fn args_r_to_l
637 -- Detect and extract relevant info for the tagToEnum kludge.
638 maybe_is_tagToEnum_call
639 = let extract_constr_Names ty
640 | Just (tyc, []) <- splitTyConApp_maybe (repType ty),
642 = map (getName . dataConWorkId) (tyConDataCons tyc)
643 -- NOTE: use the worker name, not the source name of
644 -- the DataCon. See DataCon.lhs for details.
646 = panic "maybe_is_tagToEnum_call.extract_constr_Ids"
649 (AnnApp (_, AnnApp (_, AnnVar v) (_, AnnType t)) arg)
650 -> case isPrimOpId_maybe v of
651 Just TagToEnumOp -> Just (snd arg, extract_constr_Names t)
655 -- Extract the args (R->L) and fn
656 -- The function will necessarily be a variable,
657 -- because we are compiling a tail call
658 (AnnVar fn, args_r_to_l) = splitApp app
660 -- Only consider this to be a constructor application iff it is
661 -- saturated. Otherwise, we'll call the constructor wrapper.
662 n_args = length args_r_to_l
664 = case isDataConWorkId_maybe fn of
665 Just con | dataConRepArity con == n_args -> Just con
668 -- -----------------------------------------------------------------------------
669 -- Generate code to build a constructor application,
670 -- leaving it on top of the stack
672 mkConAppCode :: Word16 -> Sequel -> BCEnv
673 -> DataCon -- The data constructor
674 -> [AnnExpr' Id VarSet] -- Args, in *reverse* order
677 mkConAppCode _ _ _ con [] -- Nullary constructor
678 = ASSERT( isNullaryRepDataCon con )
679 return (unitOL (PUSH_G (getName (dataConWorkId con))))
680 -- Instead of doing a PACK, which would allocate a fresh
681 -- copy of this constructor, use the single shared version.
683 mkConAppCode orig_d _ p con args_r_to_l
684 = ASSERT( dataConRepArity con == length args_r_to_l )
685 do_pushery orig_d (non_ptr_args ++ ptr_args)
687 -- The args are already in reverse order, which is the way PACK
688 -- expects them to be. We must push the non-ptrs after the ptrs.
689 (ptr_args, non_ptr_args) = partition isPtrAtom args_r_to_l
691 do_pushery d (arg:args)
692 = do (push, arg_words) <- pushAtom d p arg
693 more_push_code <- do_pushery (d+arg_words) args
694 return (push `appOL` more_push_code)
696 = return (unitOL (PACK con n_arg_words))
698 n_arg_words = d - orig_d
701 -- -----------------------------------------------------------------------------
702 -- Returning an unboxed tuple with one non-void component (the only
703 -- case we can handle).
705 -- Remember, we don't want to *evaluate* the component that is being
706 -- returned, even if it is a pointed type. We always just return.
709 :: Word16 -> Sequel -> BCEnv
710 -> AnnExpr' Id VarSet -> BcM BCInstrList
711 unboxedTupleReturn d s p arg = do
712 (push, sz) <- pushAtom d p arg
714 mkSLIDE sz (d-s) `snocOL`
715 RETURN_UBX (atomRep arg))
717 -- -----------------------------------------------------------------------------
718 -- Generate code for a tail-call
721 :: Word16 -> Sequel -> BCEnv
722 -> Id -> [AnnExpr' Id VarSet]
724 doTailCall init_d s p fn args
725 = do_pushes init_d args (map atomRep args)
727 do_pushes d [] reps = do
728 ASSERT( null reps ) return ()
729 (push_fn, sz) <- pushAtom d p (AnnVar fn)
730 ASSERT( sz == 1 ) return ()
731 return (push_fn `appOL` (
732 mkSLIDE ((d-init_d) + 1) (init_d - s) `appOL`
734 do_pushes d args reps = do
735 let (push_apply, n, rest_of_reps) = findPushSeq reps
736 (these_args, rest_of_args) = splitAt n args
737 (next_d, push_code) <- push_seq d these_args
738 instrs <- do_pushes (next_d + 1) rest_of_args rest_of_reps
739 -- ^^^ for the PUSH_APPLY_ instruction
740 return (push_code `appOL` (push_apply `consOL` instrs))
742 push_seq d [] = return (d, nilOL)
743 push_seq d (arg:args) = do
744 (push_code, sz) <- pushAtom d p arg
745 (final_d, more_push_code) <- push_seq (d+sz) args
746 return (final_d, push_code `appOL` more_push_code)
748 -- v. similar to CgStackery.findMatch, ToDo: merge
749 findPushSeq :: [CgRep] -> (BCInstr, Int, [CgRep])
750 findPushSeq (PtrArg: PtrArg: PtrArg: PtrArg: PtrArg: PtrArg: rest)
751 = (PUSH_APPLY_PPPPPP, 6, rest)
752 findPushSeq (PtrArg: PtrArg: PtrArg: PtrArg: PtrArg: rest)
753 = (PUSH_APPLY_PPPPP, 5, rest)
754 findPushSeq (PtrArg: PtrArg: PtrArg: PtrArg: rest)
755 = (PUSH_APPLY_PPPP, 4, rest)
756 findPushSeq (PtrArg: PtrArg: PtrArg: rest)
757 = (PUSH_APPLY_PPP, 3, rest)
758 findPushSeq (PtrArg: PtrArg: rest)
759 = (PUSH_APPLY_PP, 2, rest)
760 findPushSeq (PtrArg: rest)
761 = (PUSH_APPLY_P, 1, rest)
762 findPushSeq (VoidArg: rest)
763 = (PUSH_APPLY_V, 1, rest)
764 findPushSeq (NonPtrArg: rest)
765 = (PUSH_APPLY_N, 1, rest)
766 findPushSeq (FloatArg: rest)
767 = (PUSH_APPLY_F, 1, rest)
768 findPushSeq (DoubleArg: rest)
769 = (PUSH_APPLY_D, 1, rest)
770 findPushSeq (LongArg: rest)
771 = (PUSH_APPLY_L, 1, rest)
773 = panic "ByteCodeGen.findPushSeq"
775 -- -----------------------------------------------------------------------------
778 doCase :: Word16 -> Sequel -> BCEnv
779 -> AnnExpr Id VarSet -> Id -> [AnnAlt Id VarSet]
780 -> Bool -- True <=> is an unboxed tuple case, don't enter the result
782 doCase d s p (_,scrut) bndr alts is_unboxed_tuple
784 -- Top of stack is the return itbl, as usual.
785 -- underneath it is the pointer to the alt_code BCO.
786 -- When an alt is entered, it assumes the returned value is
787 -- on top of the itbl.
790 -- An unlifted value gets an extra info table pushed on top
791 -- when it is returned.
792 unlifted_itbl_sizeW | isAlgCase = 0
795 -- depth of stack after the return value has been pushed
796 d_bndr = d + ret_frame_sizeW + fromIntegral (idSizeW bndr)
798 -- depth of stack after the extra info table for an unboxed return
799 -- has been pushed, if any. This is the stack depth at the
801 d_alts = d_bndr + unlifted_itbl_sizeW
803 -- Env in which to compile the alts, not including
804 -- any vars bound by the alts themselves
805 p_alts = addToFM p bndr (d_bndr - 1)
807 bndr_ty = idType bndr
808 isAlgCase = not (isUnLiftedType bndr_ty) && not is_unboxed_tuple
810 -- given an alt, return a discr and code for it.
811 codeAlt (DEFAULT, _, (_,rhs))
812 = do rhs_code <- schemeE d_alts s p_alts rhs
813 return (NoDiscr, rhs_code)
815 codeAlt alt@(_, bndrs, (_,rhs))
816 -- primitive or nullary constructor alt: no need to UNPACK
817 | null real_bndrs = do
818 rhs_code <- schemeE d_alts s p_alts rhs
819 return (my_discr alt, rhs_code)
820 -- algebraic alt with some binders
823 (ptrs,nptrs) = partition (isFollowableArg.idCgRep) real_bndrs
824 ptr_sizes = map (fromIntegral . idSizeW) ptrs
825 nptrs_sizes = map (fromIntegral . idSizeW) nptrs
826 bind_sizes = ptr_sizes ++ nptrs_sizes
827 size = sum ptr_sizes + sum nptrs_sizes
828 -- the UNPACK instruction unpacks in reverse order...
829 p' = addListToFM p_alts
830 (zip (reverse (ptrs ++ nptrs))
831 (mkStackOffsets d_alts (reverse bind_sizes)))
834 rhs_code <- schemeE (d_alts+size) s p' rhs
835 return (my_discr alt, unitOL (UNPACK size) `appOL` rhs_code)
837 real_bndrs = filter (not.isTyVar) bndrs
839 my_discr (DEFAULT, _, _) = NoDiscr {-shouldn't really happen-}
840 my_discr (DataAlt dc, _, _)
841 | isUnboxedTupleCon dc
842 = unboxedTupleException
844 = DiscrP (fromIntegral (dataConTag dc - fIRST_TAG))
845 my_discr (LitAlt l, _, _)
846 = case l of MachInt i -> DiscrI (fromInteger i)
847 MachWord w -> DiscrW (fromInteger w)
848 MachFloat r -> DiscrF (fromRational r)
849 MachDouble r -> DiscrD (fromRational r)
850 MachChar i -> DiscrI (ord i)
851 _ -> pprPanic "schemeE(AnnCase).my_discr" (ppr l)
854 | not isAlgCase = Nothing
856 = case [dc | (DataAlt dc, _, _) <- alts] of
858 (dc:_) -> Just (tyConFamilySize (dataConTyCon dc))
860 -- the bitmap is relative to stack depth d, i.e. before the
861 -- BCO, info table and return value are pushed on.
862 -- This bit of code is v. similar to buildLivenessMask in CgBindery,
863 -- except that here we build the bitmap from the known bindings of
864 -- things that are pointers, whereas in CgBindery the code builds the
865 -- bitmap from the free slots and unboxed bindings.
868 -- NOTE [7/12/2006] bug #1013, testcase ghci/should_run/ghci002.
869 -- The bitmap must cover the portion of the stack up to the sequel only.
870 -- Previously we were building a bitmap for the whole depth (d), but we
871 -- really want a bitmap up to depth (d-s). This affects compilation of
872 -- case-of-case expressions, which is the only time we can be compiling a
873 -- case expression with s /= 0.
876 bitmap_size' = fromIntegral bitmap_size
877 bitmap = intsToReverseBitmap bitmap_size'{-size-}
878 (sortLe (<=) (filter (< bitmap_size') rel_slots))
881 rel_slots = map fromIntegral $ concat (map spread binds)
883 | isFollowableArg (idCgRep id) = [ rel_offset ]
885 where rel_offset = d - offset - 1
888 alt_stuff <- mapM codeAlt alts
889 alt_final <- mkMultiBranch maybe_ncons alt_stuff
892 alt_bco_name = getName bndr
893 alt_bco = mkProtoBCO alt_bco_name alt_final (Left alts)
894 0{-no arity-} bitmap_size bitmap True{-is alts-}
896 -- trace ("case: bndr = " ++ showSDocDebug (ppr bndr) ++ "\ndepth = " ++ show d ++ "\nenv = \n" ++ showSDocDebug (ppBCEnv p) ++
897 -- "\n bitmap = " ++ show bitmap) $ do
898 scrut_code <- schemeE (d + ret_frame_sizeW) (d + ret_frame_sizeW) p scrut
899 alt_bco' <- emitBc alt_bco
901 | isAlgCase = PUSH_ALTS alt_bco'
902 | otherwise = PUSH_ALTS_UNLIFTED alt_bco' (typeCgRep bndr_ty)
903 return (push_alts `consOL` scrut_code)
906 -- -----------------------------------------------------------------------------
907 -- Deal with a CCall.
909 -- Taggedly push the args onto the stack R->L,
910 -- deferencing ForeignObj#s and adjusting addrs to point to
911 -- payloads in Ptr/Byte arrays. Then, generate the marshalling
912 -- (machine) code for the ccall, and create bytecodes to call that and
913 -- then return in the right way.
915 generateCCall :: Word16 -> Sequel -- stack and sequel depths
917 -> CCallSpec -- where to call
918 -> Id -- of target, for type info
919 -> [AnnExpr' Id VarSet] -- args (atoms)
922 generateCCall d0 s p (CCallSpec target cconv _) fn args_r_to_l
926 addr_sizeW = fromIntegral (cgRepSizeW NonPtrArg)
928 -- Get the args on the stack, with tags and suitably
929 -- dereferenced for the CCall. For each arg, return the
930 -- depth to the first word of the bits for that arg, and the
931 -- CgRep of what was actually pushed.
933 pargs _ [] = return []
935 = let arg_ty = repType (exprType (deAnnotate' a))
937 in case splitTyConApp_maybe arg_ty of
938 -- Don't push the FO; instead push the Addr# it
941 | t == arrayPrimTyCon || t == mutableArrayPrimTyCon
942 -> do rest <- pargs (d + addr_sizeW) az
943 code <- parg_ArrayishRep (fromIntegral arrPtrsHdrSize) d p a
944 return ((code,AddrRep):rest)
946 | t == byteArrayPrimTyCon || t == mutableByteArrayPrimTyCon
947 -> do rest <- pargs (d + addr_sizeW) az
948 code <- parg_ArrayishRep (fromIntegral arrWordsHdrSize) d p a
949 return ((code,AddrRep):rest)
951 -- Default case: push taggedly, but otherwise intact.
953 -> do (code_a, sz_a) <- pushAtom d p a
954 rest <- pargs (d+sz_a) az
955 return ((code_a, atomPrimRep a) : rest)
957 -- Do magic for Ptr/Byte arrays. Push a ptr to the array on
958 -- the stack but then advance it over the headers, so as to
959 -- point to the payload.
960 parg_ArrayishRep :: Word16 -> Word16 -> BCEnv -> AnnExpr' Id VarSet
962 parg_ArrayishRep hdrSize d p a
963 = do (push_fo, _) <- pushAtom d p a
964 -- The ptr points at the header. Advance it over the
965 -- header and then pretend this is an Addr#.
966 return (push_fo `snocOL` SWIZZLE 0 hdrSize)
969 code_n_reps <- pargs d0 args_r_to_l
971 (pushs_arg, a_reps_pushed_r_to_l) = unzip code_n_reps
972 a_reps_sizeW = fromIntegral (sum (map primRepSizeW a_reps_pushed_r_to_l))
974 push_args = concatOL pushs_arg
975 d_after_args = d0 + a_reps_sizeW
977 | null a_reps_pushed_r_to_l || head a_reps_pushed_r_to_l /= VoidRep
978 = panic "ByteCodeGen.generateCCall: missing or invalid World token?"
980 = reverse (tail a_reps_pushed_r_to_l)
982 -- Now: a_reps_pushed_RAW are the reps which are actually on the stack.
983 -- push_args is the code to do that.
984 -- d_after_args is the stack depth once the args are on.
986 -- Get the result rep.
987 (returns_void, r_rep)
988 = case maybe_getCCallReturnRep (idType fn) of
989 Nothing -> (True, VoidRep)
990 Just rr -> (False, rr)
992 Because the Haskell stack grows down, the a_reps refer to
993 lowest to highest addresses in that order. The args for the call
994 are on the stack. Now push an unboxed Addr# indicating
995 the C function to call. Then push a dummy placeholder for the
996 result. Finally, emit a CCALL insn with an offset pointing to the
997 Addr# just pushed, and a literal field holding the mallocville
998 address of the piece of marshalling code we generate.
999 So, just prior to the CCALL insn, the stack looks like this
1000 (growing down, as usual):
1005 Addr# address_of_C_fn
1006 <placeholder-for-result#> (must be an unboxed type)
1008 The interpreter then calls the marshall code mentioned
1009 in the CCALL insn, passing it (& <placeholder-for-result#>),
1010 that is, the addr of the topmost word in the stack.
1011 When this returns, the placeholder will have been
1012 filled in. The placeholder is slid down to the sequel
1013 depth, and we RETURN.
1015 This arrangement makes it simple to do f-i-dynamic since the Addr#
1016 value is the first arg anyway.
1018 The marshalling code is generated specifically for this
1019 call site, and so knows exactly the (Haskell) stack
1020 offsets of the args, fn address and placeholder. It
1021 copies the args to the C stack, calls the stacked addr,
1022 and parks the result back in the placeholder. The interpreter
1023 calls it as a normal C call, assuming it has a signature
1024 void marshall_code ( StgWord* ptr_to_top_of_stack )
1026 -- resolve static address
1030 -> return (False, panic "ByteCodeGen.generateCCall(dyn)")
1032 -> do res <- ioToBc (lookupStaticPtr stdcall_adj_target)
1036 #ifdef mingw32_TARGET_OS
1037 | StdCallConv <- cconv
1038 = let size = fromIntegral a_reps_sizeW * wORD_SIZE in
1039 mkFastString (unpackFS target ++ '@':show size)
1045 (is_static, static_target_addr) <- get_target_info
1048 -- Get the arg reps, zapping the leading Addr# in the dynamic case
1049 a_reps -- | trace (showSDoc (ppr a_reps_pushed_RAW)) False = error "???"
1050 | is_static = a_reps_pushed_RAW
1051 | otherwise = if null a_reps_pushed_RAW
1052 then panic "ByteCodeGen.generateCCall: dyn with no args"
1053 else tail a_reps_pushed_RAW
1056 (push_Addr, d_after_Addr)
1058 = (toOL [PUSH_UBX (Right static_target_addr) addr_sizeW],
1059 d_after_args + addr_sizeW)
1060 | otherwise -- is already on the stack
1061 = (nilOL, d_after_args)
1063 -- Push the return placeholder. For a call returning nothing,
1064 -- this is a VoidArg (tag).
1065 r_sizeW = fromIntegral (primRepSizeW r_rep)
1066 d_after_r = d_after_Addr + r_sizeW
1067 r_lit = mkDummyLiteral r_rep
1068 push_r = (if returns_void
1070 else unitOL (PUSH_UBX (Left r_lit) r_sizeW))
1072 -- generate the marshalling code we're going to call
1074 -- Offset of the next stack frame down the stack. The CCALL
1075 -- instruction needs to describe the chunk of stack containing
1076 -- the ccall args to the GC, so it needs to know how large it
1077 -- is. See comment in Interpreter.c with the CCALL instruction.
1078 stk_offset = d_after_r - s
1081 -- the only difference in libffi mode is that we prepare a cif
1082 -- describing the call type by calling libffi, and we attach the
1083 -- address of this to the CCALL instruction.
1084 token <- ioToBc $ prepForeignCall cconv a_reps r_rep
1085 let addr_of_marshaller = castPtrToFunPtr token
1087 recordItblMallocBc (ItblPtr (castFunPtrToPtr addr_of_marshaller))
1090 do_call = unitOL (CCALL stk_offset (castFunPtrToPtr addr_of_marshaller))
1092 wrapup = mkSLIDE r_sizeW (d_after_r - r_sizeW - s)
1093 `snocOL` RETURN_UBX (primRepToCgRep r_rep)
1095 --trace (show (arg1_offW, args_offW , (map cgRepSizeW a_reps) )) $
1098 push_Addr `appOL` push_r `appOL` do_call `appOL` wrapup
1101 -- Make a dummy literal, to be used as a placeholder for FFI return
1102 -- values on the stack.
1103 mkDummyLiteral :: PrimRep -> Literal
1107 WordRep -> MachWord 0
1108 AddrRep -> MachNullAddr
1109 DoubleRep -> MachDouble 0
1110 FloatRep -> MachFloat 0
1111 Int64Rep -> MachInt64 0
1112 Word64Rep -> MachWord64 0
1113 _ -> panic "mkDummyLiteral"
1117 -- GHC.Prim.Char# -> GHC.Prim.State# GHC.Prim.RealWorld
1118 -- -> (# GHC.Prim.State# GHC.Prim.RealWorld, GHC.Prim.Int# #)
1121 -- and check that an unboxed pair is returned wherein the first arg is VoidArg'd.
1123 -- Alternatively, for call-targets returning nothing, convert
1125 -- GHC.Prim.Char# -> GHC.Prim.State# GHC.Prim.RealWorld
1126 -- -> (# GHC.Prim.State# GHC.Prim.RealWorld #)
1130 maybe_getCCallReturnRep :: Type -> Maybe PrimRep
1131 maybe_getCCallReturnRep fn_ty
1132 = let (_a_tys, r_ty) = splitFunTys (dropForAlls fn_ty)
1134 = if isSingleton r_reps then Nothing else Just (r_reps !! 1)
1136 = case splitTyConApp_maybe (repType r_ty) of
1137 (Just (tyc, tys)) -> (tyc, map typePrimRep tys)
1139 ok = ( ( r_reps `lengthIs` 2 && VoidRep == head r_reps)
1140 || r_reps == [VoidRep] )
1141 && isUnboxedTupleTyCon r_tycon
1142 && case maybe_r_rep_to_go of
1144 Just r_rep -> r_rep /= PtrRep
1145 -- if it was, it would be impossible
1146 -- to create a valid return value
1147 -- placeholder on the stack
1148 blargh = pprPanic "maybe_getCCallReturn: can't handle:"
1151 --trace (showSDoc (ppr (a_reps, r_reps))) $
1152 if ok then maybe_r_rep_to_go else blargh
1154 -- Compile code which expects an unboxed Int on the top of stack,
1155 -- (call it i), and pushes the i'th closure in the supplied list
1156 -- as a consequence.
1157 implement_tagToId :: [Name] -> BcM BCInstrList
1158 implement_tagToId names
1159 = ASSERT( notNull names )
1160 do labels <- getLabelsBc (genericLength names)
1161 label_fail <- getLabelBc
1162 label_exit <- getLabelBc
1163 let infos = zip4 labels (tail labels ++ [label_fail])
1165 steps = map (mkStep label_exit) infos
1166 return (concatOL steps
1168 toOL [LABEL label_fail, CASEFAIL, LABEL label_exit])
1170 mkStep l_exit (my_label, next_label, n, name_for_n)
1171 = toOL [LABEL my_label,
1172 TESTEQ_I n next_label,
1177 -- -----------------------------------------------------------------------------
1180 -- Push an atom onto the stack, returning suitable code & number of
1181 -- stack words used.
1183 -- The env p must map each variable to the highest- numbered stack
1184 -- slot for it. For example, if the stack has depth 4 and we
1185 -- tagged-ly push (v :: Int#) on it, the value will be in stack[4],
1186 -- the tag in stack[5], the stack will have depth 6, and p must map v
1187 -- to 5 and not to 4. Stack locations are numbered from zero, so a
1188 -- depth 6 stack has valid words 0 .. 5.
1190 pushAtom :: Word16 -> BCEnv -> AnnExpr' Id VarSet -> BcM (BCInstrList, Word16)
1193 | Just e' <- bcView e
1196 pushAtom d p (AnnVar v)
1197 | idCgRep v == VoidArg
1201 = pprPanic "pushAtom: shouldn't get an FCallId here" (ppr v)
1203 | Just primop <- isPrimOpId_maybe v
1204 = return (unitOL (PUSH_PRIMOP primop), 1)
1206 | Just d_v <- lookupBCEnv_maybe p v -- v is a local variable
1207 = let l = d - d_v + sz - 2
1208 in return (toOL (genericReplicate sz (PUSH_L l)), sz)
1209 -- d - d_v the number of words between the TOS
1210 -- and the 1st slot of the object
1212 -- d - d_v - 1 the offset from the TOS of the 1st slot
1214 -- d - d_v - 1 + sz - 1 the offset from the TOS of the last slot
1217 -- Having found the last slot, we proceed to copy the right number of
1218 -- slots on to the top of the stack.
1220 | otherwise -- v must be a global variable
1222 return (unitOL (PUSH_G (getName v)), sz)
1226 sz = fromIntegral (idSizeW v)
1229 pushAtom _ _ (AnnLit lit)
1231 MachLabel _ _ _ -> code NonPtrArg
1232 MachWord _ -> code NonPtrArg
1233 MachInt _ -> code PtrArg
1234 MachFloat _ -> code FloatArg
1235 MachDouble _ -> code DoubleArg
1236 MachChar _ -> code NonPtrArg
1237 MachNullAddr -> code NonPtrArg
1238 MachStr s -> pushStr s
1239 l -> pprPanic "pushAtom" (ppr l)
1242 = let size_host_words = fromIntegral (cgRepSizeW rep)
1243 in return (unitOL (PUSH_UBX (Left lit) size_host_words),
1247 = let getMallocvilleAddr
1249 FastString _ n _ fp _ ->
1250 -- we could grab the Ptr from the ForeignPtr,
1251 -- but then we have no way to control its lifetime.
1252 -- In reality it'll probably stay alive long enoungh
1253 -- by virtue of the global FastString table, but
1254 -- to be on the safe side we copy the string into
1255 -- a malloc'd area of memory.
1256 do ptr <- ioToBc (mallocBytes (n+1))
1259 withForeignPtr fp $ \p -> do
1260 memcpy ptr p (fromIntegral n)
1261 pokeByteOff ptr n (fromIntegral (ord '\0') :: Word8)
1265 addr <- getMallocvilleAddr
1266 -- Get the addr on the stack, untaggedly
1267 return (unitOL (PUSH_UBX (Right addr) 1), 1)
1269 pushAtom d p (AnnCast e _)
1270 = pushAtom d p (snd e)
1273 = pprPanic "ByteCodeGen.pushAtom"
1274 (pprCoreExpr (deAnnotate (undefined, expr)))
1276 foreign import ccall unsafe "memcpy"
1277 memcpy :: Ptr a -> Ptr b -> CSize -> IO ()
1280 -- -----------------------------------------------------------------------------
1281 -- Given a bunch of alts code and their discrs, do the donkey work
1282 -- of making a multiway branch using a switch tree.
1283 -- What a load of hassle!
1285 mkMultiBranch :: Maybe Int -- # datacons in tycon, if alg alt
1286 -- a hint; generates better code
1287 -- Nothing is always safe
1288 -> [(Discr, BCInstrList)]
1290 mkMultiBranch maybe_ncons raw_ways
1291 = let d_way = filter (isNoDiscr.fst) raw_ways
1293 (\w1 w2 -> leAlt (fst w1) (fst w2))
1294 (filter (not.isNoDiscr.fst) raw_ways)
1296 mkTree :: [(Discr, BCInstrList)] -> Discr -> Discr -> BcM BCInstrList
1297 mkTree [] _range_lo _range_hi = return the_default
1299 mkTree [val] range_lo range_hi
1300 | range_lo `eqAlt` range_hi
1303 = do label_neq <- getLabelBc
1304 return (mkTestEQ (fst val) label_neq
1306 `appOL` unitOL (LABEL label_neq)
1307 `appOL` the_default))
1309 mkTree vals range_lo range_hi
1310 = let n = length vals `div` 2
1311 vals_lo = take n vals
1312 vals_hi = drop n vals
1313 v_mid = fst (head vals_hi)
1315 label_geq <- getLabelBc
1316 code_lo <- mkTree vals_lo range_lo (dec v_mid)
1317 code_hi <- mkTree vals_hi v_mid range_hi
1318 return (mkTestLT v_mid label_geq
1320 `appOL` unitOL (LABEL label_geq)
1324 = case d_way of [] -> unitOL CASEFAIL
1326 _ -> panic "mkMultiBranch/the_default"
1328 -- None of these will be needed if there are no non-default alts
1329 (mkTestLT, mkTestEQ, init_lo, init_hi)
1331 = panic "mkMultiBranch: awesome foursome"
1333 = case fst (head notd_ways) of {
1334 DiscrI _ -> ( \(DiscrI i) fail_label -> TESTLT_I i fail_label,
1335 \(DiscrI i) fail_label -> TESTEQ_I i fail_label,
1338 DiscrW _ -> ( \(DiscrW i) fail_label -> TESTLT_W i fail_label,
1339 \(DiscrW i) fail_label -> TESTEQ_W i fail_label,
1342 DiscrF _ -> ( \(DiscrF f) fail_label -> TESTLT_F f fail_label,
1343 \(DiscrF f) fail_label -> TESTEQ_F f fail_label,
1346 DiscrD _ -> ( \(DiscrD d) fail_label -> TESTLT_D d fail_label,
1347 \(DiscrD d) fail_label -> TESTEQ_D d fail_label,
1350 DiscrP _ -> ( \(DiscrP i) fail_label -> TESTLT_P i fail_label,
1351 \(DiscrP i) fail_label -> TESTEQ_P i fail_label,
1353 DiscrP algMaxBound );
1354 NoDiscr -> panic "mkMultiBranch NoDiscr"
1357 (algMinBound, algMaxBound)
1358 = case maybe_ncons of
1359 -- XXX What happens when n == 0?
1360 Just n -> (0, fromIntegral n - 1)
1361 Nothing -> (minBound, maxBound)
1363 (DiscrI i1) `eqAlt` (DiscrI i2) = i1 == i2
1364 (DiscrW w1) `eqAlt` (DiscrW w2) = w1 == w2
1365 (DiscrF f1) `eqAlt` (DiscrF f2) = f1 == f2
1366 (DiscrD d1) `eqAlt` (DiscrD d2) = d1 == d2
1367 (DiscrP i1) `eqAlt` (DiscrP i2) = i1 == i2
1368 NoDiscr `eqAlt` NoDiscr = True
1371 (DiscrI i1) `leAlt` (DiscrI i2) = i1 <= i2
1372 (DiscrW w1) `leAlt` (DiscrW w2) = w1 <= w2
1373 (DiscrF f1) `leAlt` (DiscrF f2) = f1 <= f2
1374 (DiscrD d1) `leAlt` (DiscrD d2) = d1 <= d2
1375 (DiscrP i1) `leAlt` (DiscrP i2) = i1 <= i2
1376 NoDiscr `leAlt` NoDiscr = True
1379 isNoDiscr NoDiscr = True
1382 dec (DiscrI i) = DiscrI (i-1)
1383 dec (DiscrW w) = DiscrW (w-1)
1384 dec (DiscrP i) = DiscrP (i-1)
1385 dec other = other -- not really right, but if you
1386 -- do cases on floating values, you'll get what you deserve
1388 -- same snotty comment applies to the following
1390 minD, maxD :: Double
1396 mkTree notd_ways init_lo init_hi
1399 -- -----------------------------------------------------------------------------
1400 -- Supporting junk for the compilation schemes
1402 -- Describes case alts
1411 instance Outputable Discr where
1412 ppr (DiscrI i) = int i
1413 ppr (DiscrW w) = text (show w)
1414 ppr (DiscrF f) = text (show f)
1415 ppr (DiscrD d) = text (show d)
1416 ppr (DiscrP i) = ppr i
1417 ppr NoDiscr = text "DEF"
1420 lookupBCEnv_maybe :: BCEnv -> Id -> Maybe Word16
1421 lookupBCEnv_maybe = lookupFM
1423 idSizeW :: Id -> Int
1424 idSizeW id = cgRepSizeW (typeCgRep (idType id))
1427 unboxedTupleException :: a
1428 unboxedTupleException
1431 ("Error: bytecode compiler can't handle unboxed tuples.\n"++
1432 " Possibly due to foreign import/export decls in source.\n"++
1433 " Workaround: use -fobject-code, or compile this module to .o separately."))
1436 mkSLIDE :: Word16 -> Word16 -> OrdList BCInstr
1437 mkSLIDE n d = if d == 0 then nilOL else unitOL (SLIDE n d)
1439 splitApp :: AnnExpr' Var ann -> (AnnExpr' Var ann, [AnnExpr' Var ann])
1440 -- The arguments are returned in *right-to-left* order
1441 splitApp e | Just e' <- bcView e = splitApp e'
1442 splitApp (AnnApp (_,f) (_,a)) = case splitApp f of
1443 (f', as) -> (f', a:as)
1444 splitApp e = (e, [])
1447 bcView :: AnnExpr' Var ann -> Maybe (AnnExpr' Var ann)
1448 -- The "bytecode view" of a term discards
1449 -- a) type abstractions
1450 -- b) type applications
1453 -- Type lambdas *can* occur in random expressions,
1454 -- whereas value lambdas cannot; that is why they are nuked here
1455 bcView (AnnNote _ (_,e)) = Just e
1456 bcView (AnnCast (_,e) _) = Just e
1457 bcView (AnnLam v (_,e)) | isTyVar v = Just e
1458 bcView (AnnApp (_,e) (_, AnnType _)) = Just e
1461 isVoidArgAtom :: AnnExpr' Var ann -> Bool
1462 isVoidArgAtom e | Just e' <- bcView e = isVoidArgAtom e'
1463 isVoidArgAtom (AnnVar v) = typePrimRep (idType v) == VoidRep
1464 isVoidArgAtom _ = False
1466 atomPrimRep :: AnnExpr' Id ann -> PrimRep
1467 atomPrimRep e | Just e' <- bcView e = atomPrimRep e'
1468 atomPrimRep (AnnVar v) = typePrimRep (idType v)
1469 atomPrimRep (AnnLit l) = typePrimRep (literalType l)
1470 atomPrimRep other = pprPanic "atomPrimRep" (ppr (deAnnotate (undefined,other)))
1472 atomRep :: AnnExpr' Id ann -> CgRep
1473 atomRep e = primRepToCgRep (atomPrimRep e)
1475 isPtrAtom :: AnnExpr' Id ann -> Bool
1476 isPtrAtom e = atomRep e == PtrArg
1478 -- Let szsw be the sizes in words of some items pushed onto the stack,
1479 -- which has initial depth d'. Return the values which the stack environment
1480 -- should map these items to.
1481 mkStackOffsets :: Word16 -> [Word16] -> [Word16]
1482 mkStackOffsets original_depth szsw
1483 = map (subtract 1) (tail (scanl (+) original_depth szsw))
1485 -- -----------------------------------------------------------------------------
1486 -- The bytecode generator's monad
1488 type BcPtr = Either ItblPtr (Ptr ())
1492 uniqSupply :: UniqSupply, -- for generating fresh variable names
1493 nextlabel :: Word16, -- for generating local labels
1494 malloced :: [BcPtr], -- thunks malloced for current BCO
1495 -- Should be free()d when it is GCd
1496 breakArray :: BreakArray -- array of breakpoint flags
1499 newtype BcM r = BcM (BcM_State -> IO (BcM_State, r))
1501 ioToBc :: IO a -> BcM a
1502 ioToBc io = BcM $ \st -> do
1506 runBc :: UniqSupply -> ModBreaks -> BcM r -> IO (BcM_State, r)
1507 runBc us modBreaks (BcM m)
1508 = m (BcM_State us 0 [] breakArray)
1510 breakArray = modBreaks_flags modBreaks
1512 thenBc :: BcM a -> (a -> BcM b) -> BcM b
1513 thenBc (BcM expr) cont = BcM $ \st0 -> do
1514 (st1, q) <- expr st0
1519 thenBc_ :: BcM a -> BcM b -> BcM b
1520 thenBc_ (BcM expr) (BcM cont) = BcM $ \st0 -> do
1521 (st1, _) <- expr st0
1522 (st2, r) <- cont st1
1525 returnBc :: a -> BcM a
1526 returnBc result = BcM $ \st -> (return (st, result))
1528 instance Monad BcM where
1533 emitBc :: ([BcPtr] -> ProtoBCO Name) -> BcM (ProtoBCO Name)
1535 = BcM $ \st -> return (st{malloced=[]}, bco (malloced st))
1537 recordMallocBc :: Ptr a -> BcM ()
1539 = BcM $ \st -> return (st{malloced = Right (castPtr a) : malloced st}, ())
1541 recordItblMallocBc :: ItblPtr -> BcM ()
1542 recordItblMallocBc a
1543 = BcM $ \st -> return (st{malloced = Left a : malloced st}, ())
1545 getLabelBc :: BcM Word16
1547 = BcM $ \st -> do let nl = nextlabel st
1548 when (nl == maxBound) $
1549 panic "getLabelBc: Ran out of labels"
1550 return (st{nextlabel = nl + 1}, nl)
1552 getLabelsBc :: Word16 -> BcM [Word16]
1554 = BcM $ \st -> let ctr = nextlabel st
1555 in return (st{nextlabel = ctr+n}, [ctr .. ctr+n-1])
1557 getBreakArray :: BcM BreakArray
1558 getBreakArray = BcM $ \st -> return (st, breakArray st)
1560 newUnique :: BcM Unique
1562 \st -> case splitUniqSupply (uniqSupply st) of
1563 (us1, us2) -> let newState = st { uniqSupply = us2 }
1564 in return (newState, uniqFromSupply us1)
1566 newId :: Type -> BcM Id
1569 return $ mkSysLocal tickFS uniq ty
1571 tickFS :: FastString
1572 tickFS = fsLit "ticked"