2 -- The above warning supression flag is a temporary kludge.
3 -- While working on this module you are encouraged to remove it and fix
4 -- any warnings in the module. See
5 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
8 -----------------------------------------------------------------------------
10 -- Code generator utilities; mostly monadic
12 -- (c) The University of Glasgow 2004-2006
14 -----------------------------------------------------------------------------
19 emitDataLits, mkDataLits,
20 emitRODataLits, mkRODataLits,
21 emitIf, emitIfThenElse,
22 emitRtsCall, emitRtsCallWithVols, emitRtsCallWithResult,
23 assignTemp, assignTemp_, newTemp,
25 emitSwitch, emitLitSwitch,
28 callerSaves, callerSaveVolatileRegs, get_GlobalReg_addr,
29 activeStgRegs, fixStgRegisters,
31 cmmAndWord, cmmOrWord, cmmNegate, cmmEqWord, cmmNeWord,
32 cmmUGtWord, cmmSubWord, cmmMulWord, cmmAddWord, cmmUShrWord,
33 cmmOffsetExprW, cmmOffsetExprB,
34 cmmRegOffW, cmmRegOffB,
35 cmmLabelOffW, cmmLabelOffB,
36 cmmOffsetW, cmmOffsetB,
37 cmmOffsetLitW, cmmOffsetLitB,
39 cmmConstrTag, cmmConstrTag1,
41 tagForCon, tagCons, isSmallFamily,
42 cmmUntag, cmmIsTagged, cmmGetTag,
46 mkStringCLit, mkByteStringCLit,
50 getSRTInfo, clHasCafRefs
53 #include "HsVersions.h"
54 #include "../includes/stg/MachRegs.h"
69 import StgSyn (SRT(..))
85 -------------------------------------------------------------------------
87 -- Random small functions
89 -------------------------------------------------------------------------
91 addIdReps :: [Id] -> [(CgRep, Id)]
92 addIdReps ids = [(idCgRep id, id) | id <- ids]
94 -------------------------------------------------------------------------
98 -------------------------------------------------------------------------
100 cgLit :: Literal -> FCode CmmLit
101 cgLit (MachStr s) = mkByteStringCLit (bytesFS s)
102 -- not unpackFS; we want the UTF-8 byte stream.
103 cgLit other_lit = return (mkSimpleLit other_lit)
105 mkSimpleLit :: Literal -> CmmLit
106 mkSimpleLit (MachChar c) = CmmInt (fromIntegral (ord c)) wordWidth
107 mkSimpleLit MachNullAddr = zeroCLit
108 mkSimpleLit (MachInt i) = CmmInt i wordWidth
109 mkSimpleLit (MachInt64 i) = CmmInt i W64
110 mkSimpleLit (MachWord i) = CmmInt i wordWidth
111 mkSimpleLit (MachWord64 i) = CmmInt i W64
112 mkSimpleLit (MachFloat r) = CmmFloat r W32
113 mkSimpleLit (MachDouble r) = CmmFloat r W64
114 mkSimpleLit (MachLabel fs ms fod)
115 = CmmLabel (mkForeignLabel fs ms labelSrc fod)
117 -- TODO: Literal labels might not actually be in the current package...
118 labelSrc = ForeignLabelInThisPackage
120 mkLtOp :: Literal -> MachOp
121 -- On signed literals we must do a signed comparison
122 mkLtOp (MachInt _) = MO_S_Lt wordWidth
123 mkLtOp (MachFloat _) = MO_F_Lt W32
124 mkLtOp (MachDouble _) = MO_F_Lt W64
125 mkLtOp lit = MO_U_Lt (typeWidth (cmmLitType (mkSimpleLit lit)))
128 ---------------------------------------------------
130 -- Cmm data type functions
132 ---------------------------------------------------
134 -----------------------
135 -- The "B" variants take byte offsets
136 cmmRegOffB :: CmmReg -> ByteOff -> CmmExpr
137 cmmRegOffB = cmmRegOff
139 cmmOffsetB :: CmmExpr -> ByteOff -> CmmExpr
140 cmmOffsetB = cmmOffset
142 cmmOffsetExprB :: CmmExpr -> CmmExpr -> CmmExpr
143 cmmOffsetExprB = cmmOffsetExpr
145 cmmLabelOffB :: CLabel -> ByteOff -> CmmLit
146 cmmLabelOffB = cmmLabelOff
148 cmmOffsetLitB :: CmmLit -> ByteOff -> CmmLit
149 cmmOffsetLitB = cmmOffsetLit
151 -----------------------
152 -- The "W" variants take word offsets
153 cmmOffsetExprW :: CmmExpr -> CmmExpr -> CmmExpr
154 -- The second arg is a *word* offset; need to change it to bytes
155 cmmOffsetExprW e (CmmLit (CmmInt n _)) = cmmOffsetW e (fromInteger n)
156 cmmOffsetExprW e wd_off = cmmIndexExpr wordWidth e wd_off
158 cmmOffsetW :: CmmExpr -> WordOff -> CmmExpr
159 cmmOffsetW e n = cmmOffsetB e (wORD_SIZE * n)
161 cmmRegOffW :: CmmReg -> WordOff -> CmmExpr
162 cmmRegOffW reg wd_off = cmmRegOffB reg (wd_off * wORD_SIZE)
164 cmmOffsetLitW :: CmmLit -> WordOff -> CmmLit
165 cmmOffsetLitW lit wd_off = cmmOffsetLitB lit (wORD_SIZE * wd_off)
167 cmmLabelOffW :: CLabel -> WordOff -> CmmLit
168 cmmLabelOffW lbl wd_off = cmmLabelOffB lbl (wORD_SIZE * wd_off)
170 cmmLoadIndexW :: CmmExpr -> Int -> CmmType -> CmmExpr
171 cmmLoadIndexW base off ty = CmmLoad (cmmOffsetW base off) ty
173 -----------------------
174 cmmNeWord, cmmEqWord, cmmOrWord, cmmAndWord :: CmmExpr -> CmmExpr -> CmmExpr
175 cmmOrWord e1 e2 = CmmMachOp mo_wordOr [e1, e2]
176 cmmAndWord e1 e2 = CmmMachOp mo_wordAnd [e1, e2]
177 cmmNeWord e1 e2 = CmmMachOp mo_wordNe [e1, e2]
178 cmmEqWord e1 e2 = CmmMachOp mo_wordEq [e1, e2]
179 cmmULtWord e1 e2 = CmmMachOp mo_wordULt [e1, e2]
180 cmmUGeWord e1 e2 = CmmMachOp mo_wordUGe [e1, e2]
181 cmmUGtWord e1 e2 = CmmMachOp mo_wordUGt [e1, e2]
182 --cmmShlWord e1 e2 = CmmMachOp mo_wordShl [e1, e2]
183 cmmUShrWord e1 e2 = CmmMachOp mo_wordUShr [e1, e2]
184 cmmAddWord e1 e2 = CmmMachOp mo_wordAdd [e1, e2]
185 cmmSubWord e1 e2 = CmmMachOp mo_wordSub [e1, e2]
186 cmmMulWord e1 e2 = CmmMachOp mo_wordMul [e1, e2]
188 cmmNegate :: CmmExpr -> CmmExpr
189 cmmNegate (CmmLit (CmmInt n rep)) = CmmLit (CmmInt (-n) rep)
190 cmmNegate e = CmmMachOp (MO_S_Neg (cmmExprWidth e)) [e]
192 blankWord :: CmmStatic
193 blankWord = CmmUninitialised wORD_SIZE
197 --cmmTagBits = CmmLit (mkIntCLit tAG_BITS)
198 cmmTagMask = CmmLit (mkIntCLit tAG_MASK)
199 cmmPointerMask = CmmLit (mkIntCLit (complement tAG_MASK))
201 -- Used to untag a possibly tagged pointer
202 -- A static label need not be untagged
203 cmmUntag e@(CmmLit (CmmLabel _)) = e
205 cmmUntag e = (e `cmmAndWord` cmmPointerMask)
207 cmmGetTag e = (e `cmmAndWord` cmmTagMask)
209 -- Test if a closure pointer is untagged
210 cmmIsTagged e = (e `cmmAndWord` cmmTagMask)
211 `cmmNeWord` CmmLit zeroCLit
213 cmmConstrTag e = (e `cmmAndWord` cmmTagMask) `cmmSubWord` (CmmLit (mkIntCLit 1))
214 -- Get constructor tag, but one based.
215 cmmConstrTag1 e = e `cmmAndWord` cmmTagMask
218 The family size of a data type (the number of constructors)
220 * small, if the family size < 2**tag_bits
223 Small families can have the constructor tag in the tag
225 Big families only use the tag value 1 to represent
228 isSmallFamily fam_size = fam_size <= mAX_PTR_TAG
232 con_tag = dataConTagZ con
233 fam_size = tyConFamilySize (dataConTyCon con)
234 tag | isSmallFamily fam_size = con_tag + 1
237 --Tag an expression, to do: refactor, this appears in some other module.
238 tagCons con expr = cmmOffsetB expr (tagForCon con)
240 -- Copied from CgInfoTbls.hs
241 -- We keep the *zero-indexed* tag in the srt_len field of the info
242 -- table of a data constructor.
243 dataConTagZ :: DataCon -> ConTagZ
244 dataConTagZ con = dataConTag con - fIRST_TAG
246 -----------------------
249 mkWordCLit :: StgWord -> CmmLit
250 mkWordCLit wd = CmmInt (fromIntegral wd) wordWidth
252 packHalfWordsCLit :: (Integral a, Integral b) => a -> b -> CmmLit
253 -- Make a single word literal in which the lower_half_word is
254 -- at the lower address, and the upper_half_word is at the
256 -- ToDo: consider using half-word lits instead
257 -- but be careful: that's vulnerable when reversed
258 packHalfWordsCLit lower_half_word upper_half_word
259 #ifdef WORDS_BIGENDIAN
260 = mkWordCLit ((fromIntegral lower_half_word `shiftL` hALF_WORD_SIZE_IN_BITS)
261 .|. fromIntegral upper_half_word)
263 = mkWordCLit ((fromIntegral lower_half_word)
264 .|. (fromIntegral upper_half_word `shiftL` hALF_WORD_SIZE_IN_BITS))
267 --------------------------------------------------------------------------
269 -- Incrementing a memory location
271 --------------------------------------------------------------------------
273 addToMem :: Width -- rep of the counter
274 -> CmmExpr -- Address
275 -> Int -- What to add (a word)
277 addToMem width ptr n = addToMemE width ptr (CmmLit (CmmInt (toInteger n) width))
279 addToMemE :: Width -- rep of the counter
280 -> CmmExpr -- Address
281 -> CmmExpr -- What to add (a word-typed expression)
283 addToMemE width ptr n
284 = CmmStore ptr (CmmMachOp (MO_Add width) [CmmLoad ptr (cmmBits width), n])
286 -------------------------------------------------------------------------
288 -- Converting a closure tag to a closure for enumeration types
289 -- (this is the implementation of tagToEnum#).
291 -------------------------------------------------------------------------
293 tagToClosure :: TyCon -> CmmExpr -> CmmExpr
294 tagToClosure tycon tag
295 = CmmLoad (cmmOffsetExprW closure_tbl tag) gcWord
296 where closure_tbl = CmmLit (CmmLabel lbl)
297 lbl = mkClosureTableLabel (tyConName tycon) NoCafRefs
299 -------------------------------------------------------------------------
301 -- Conditionals and rts calls
303 -------------------------------------------------------------------------
305 emitIf :: CmmExpr -- Boolean
308 -- Emit (if e then x)
309 -- ToDo: reverse the condition to avoid the extra branch instruction if possible
310 -- (some conditionals aren't reversible. eg. floating point comparisons cannot
311 -- be inverted because there exist some values for which both comparisons
312 -- return False, such as NaN.)
313 emitIf cond then_part
314 = do { then_id <- newLabelC
315 ; join_id <- newLabelC
316 ; stmtC (CmmCondBranch cond then_id)
317 ; stmtC (CmmBranch join_id)
323 emitIfThenElse :: CmmExpr -- Boolean
327 -- Emit (if e then x else y)
328 emitIfThenElse cond then_part else_part
329 = do { then_id <- newLabelC
330 ; join_id <- newLabelC
331 ; stmtC (CmmCondBranch cond then_id)
333 ; stmtC (CmmBranch join_id)
340 -- | Emit code to call a Cmm function.
342 :: PackageId -- ^ package the function is in
343 -> FastString -- ^ name of function
344 -> [CmmHinted CmmExpr] -- ^ function args
345 -> Bool -- ^ whether this is a safe call
346 -> Code -- ^ cmm code
348 emitRtsCall pkg fun args safe = emitRtsCall' [] pkg fun args Nothing safe
349 -- The 'Nothing' says "save all global registers"
351 emitRtsCallWithVols :: PackageId -> FastString -> [CmmHinted CmmExpr] -> [GlobalReg] -> Bool -> Code
352 emitRtsCallWithVols pkg fun args vols safe
353 = emitRtsCall' [] pkg fun args (Just vols) safe
355 emitRtsCallWithResult
356 :: LocalReg -> ForeignHint
357 -> PackageId -> FastString
358 -> [CmmHinted CmmExpr] -> Bool -> Code
359 emitRtsCallWithResult res hint pkg fun args safe
360 = emitRtsCall' [CmmHinted res hint] pkg fun args Nothing safe
362 -- Make a call to an RTS C procedure
364 :: [CmmHinted LocalReg]
367 -> [CmmHinted CmmExpr]
369 -> Bool -- True <=> CmmSafe call
371 emitRtsCall' res pkg fun args vols safe = do
373 then getSRTInfo >>= (return . CmmSafe)
374 else return CmmUnsafe
376 stmtC (CmmCall target res args safety CmmMayReturn)
379 (caller_save, caller_load) = callerSaveVolatileRegs vols
380 target = CmmCallee fun_expr CCallConv
381 fun_expr = mkLblExpr (mkCmmCodeLabel pkg fun)
383 -----------------------------------------------------------------------------
385 -- Caller-Save Registers
387 -----------------------------------------------------------------------------
389 -- Here we generate the sequence of saves/restores required around a
390 -- foreign call instruction.
392 -- TODO: reconcile with includes/Regs.h
393 -- * Regs.h claims that BaseReg should be saved last and loaded first
394 -- * This might not have been tickled before since BaseReg is callee save
395 -- * Regs.h saves SparkHd, ParkT1, SparkBase and SparkLim
396 callerSaveVolatileRegs :: Maybe [GlobalReg] -> ([CmmStmt], [CmmStmt])
397 callerSaveVolatileRegs vols = (caller_save, caller_load)
399 caller_save = foldr ($!) [] (map callerSaveGlobalReg regs_to_save)
400 caller_load = foldr ($!) [] (map callerRestoreGlobalReg regs_to_save)
402 system_regs = [Sp,SpLim,Hp,HpLim,CurrentTSO,CurrentNursery,
403 {-SparkHd,SparkTl,SparkBase,SparkLim,-}BaseReg ]
405 regs_to_save = system_regs ++ vol_list
407 vol_list = case vols of Nothing -> all_of_em; Just regs -> regs
409 all_of_em = [ VanillaReg n VNonGcPtr | n <- [0..mAX_Vanilla_REG] ]
410 -- The VNonGcPtr is a lie, but I don't think it matters
411 ++ [ FloatReg n | n <- [0..mAX_Float_REG] ]
412 ++ [ DoubleReg n | n <- [0..mAX_Double_REG] ]
413 ++ [ LongReg n | n <- [0..mAX_Long_REG] ]
415 callerSaveGlobalReg reg next
417 CmmStore (get_GlobalReg_addr reg)
418 (CmmReg (CmmGlobal reg)) : next
421 callerRestoreGlobalReg reg next
423 CmmAssign (CmmGlobal reg)
424 (CmmLoad (get_GlobalReg_addr reg) (globalRegType reg))
429 -- | Returns @True@ if this global register is stored in a caller-saves
432 callerSaves :: GlobalReg -> Bool
434 #ifdef CALLER_SAVES_Base
435 callerSaves BaseReg = True
437 #ifdef CALLER_SAVES_R1
438 callerSaves (VanillaReg 1 _) = True
440 #ifdef CALLER_SAVES_R2
441 callerSaves (VanillaReg 2 _) = True
443 #ifdef CALLER_SAVES_R3
444 callerSaves (VanillaReg 3 _) = True
446 #ifdef CALLER_SAVES_R4
447 callerSaves (VanillaReg 4 _) = True
449 #ifdef CALLER_SAVES_R5
450 callerSaves (VanillaReg 5 _) = True
452 #ifdef CALLER_SAVES_R6
453 callerSaves (VanillaReg 6 _) = True
455 #ifdef CALLER_SAVES_R7
456 callerSaves (VanillaReg 7 _) = True
458 #ifdef CALLER_SAVES_R8
459 callerSaves (VanillaReg 8 _) = True
461 #ifdef CALLER_SAVES_F1
462 callerSaves (FloatReg 1) = True
464 #ifdef CALLER_SAVES_F2
465 callerSaves (FloatReg 2) = True
467 #ifdef CALLER_SAVES_F3
468 callerSaves (FloatReg 3) = True
470 #ifdef CALLER_SAVES_F4
471 callerSaves (FloatReg 4) = True
473 #ifdef CALLER_SAVES_D1
474 callerSaves (DoubleReg 1) = True
476 #ifdef CALLER_SAVES_D2
477 callerSaves (DoubleReg 2) = True
479 #ifdef CALLER_SAVES_L1
480 callerSaves (LongReg 1) = True
482 #ifdef CALLER_SAVES_Sp
483 callerSaves Sp = True
485 #ifdef CALLER_SAVES_SpLim
486 callerSaves SpLim = True
488 #ifdef CALLER_SAVES_Hp
489 callerSaves Hp = True
491 #ifdef CALLER_SAVES_HpLim
492 callerSaves HpLim = True
494 #ifdef CALLER_SAVES_CurrentTSO
495 callerSaves CurrentTSO = True
497 #ifdef CALLER_SAVES_CurrentNursery
498 callerSaves CurrentNursery = True
500 callerSaves _ = False
503 -- -----------------------------------------------------------------------------
504 -- Information about global registers
506 baseRegOffset :: GlobalReg -> Int
508 baseRegOffset (VanillaReg 1 _) = oFFSET_StgRegTable_rR1
509 baseRegOffset (VanillaReg 2 _) = oFFSET_StgRegTable_rR2
510 baseRegOffset (VanillaReg 3 _) = oFFSET_StgRegTable_rR3
511 baseRegOffset (VanillaReg 4 _) = oFFSET_StgRegTable_rR4
512 baseRegOffset (VanillaReg 5 _) = oFFSET_StgRegTable_rR5
513 baseRegOffset (VanillaReg 6 _) = oFFSET_StgRegTable_rR6
514 baseRegOffset (VanillaReg 7 _) = oFFSET_StgRegTable_rR7
515 baseRegOffset (VanillaReg 8 _) = oFFSET_StgRegTable_rR8
516 baseRegOffset (VanillaReg 9 _) = oFFSET_StgRegTable_rR9
517 baseRegOffset (VanillaReg 10 _) = oFFSET_StgRegTable_rR10
518 baseRegOffset (FloatReg 1) = oFFSET_StgRegTable_rF1
519 baseRegOffset (FloatReg 2) = oFFSET_StgRegTable_rF2
520 baseRegOffset (FloatReg 3) = oFFSET_StgRegTable_rF3
521 baseRegOffset (FloatReg 4) = oFFSET_StgRegTable_rF4
522 baseRegOffset (DoubleReg 1) = oFFSET_StgRegTable_rD1
523 baseRegOffset (DoubleReg 2) = oFFSET_StgRegTable_rD2
524 baseRegOffset Sp = oFFSET_StgRegTable_rSp
525 baseRegOffset SpLim = oFFSET_StgRegTable_rSpLim
526 baseRegOffset (LongReg 1) = oFFSET_StgRegTable_rL1
527 baseRegOffset Hp = oFFSET_StgRegTable_rHp
528 baseRegOffset HpLim = oFFSET_StgRegTable_rHpLim
529 baseRegOffset CurrentTSO = oFFSET_StgRegTable_rCurrentTSO
530 baseRegOffset CurrentNursery = oFFSET_StgRegTable_rCurrentNursery
531 baseRegOffset HpAlloc = oFFSET_StgRegTable_rHpAlloc
532 baseRegOffset EagerBlackholeInfo = oFFSET_stgEagerBlackholeInfo
533 baseRegOffset GCEnter1 = oFFSET_stgGCEnter1
534 baseRegOffset GCFun = oFFSET_stgGCFun
535 baseRegOffset BaseReg = panic "baseRegOffset:BaseReg"
536 baseRegOffset _ = panic "baseRegOffset:other"
539 -------------------------------------------------------------------------
541 -- Strings generate a top-level data block
543 -------------------------------------------------------------------------
545 emitDataLits :: CLabel -> [CmmLit] -> Code
546 -- Emit a data-segment data block
547 emitDataLits lbl lits
548 = emitData Data (CmmDataLabel lbl : map CmmStaticLit lits)
550 mkDataLits :: CLabel -> [CmmLit] -> GenCmmTop CmmStatic info graph
551 -- Emit a data-segment data block
553 = CmmData Data (CmmDataLabel lbl : map CmmStaticLit lits)
555 emitRODataLits :: String -> CLabel -> [CmmLit] -> Code
556 -- Emit a read-only data block
557 emitRODataLits caller lbl lits
558 = emitData section (CmmDataLabel lbl : map CmmStaticLit lits)
559 where section | any needsRelocation lits = RelocatableReadOnlyData
560 | otherwise = ReadOnlyData
561 needsRelocation (CmmLabel _) = True
562 needsRelocation (CmmLabelOff _ _) = True
563 needsRelocation _ = False
565 mkRODataLits :: CLabel -> [CmmLit] -> GenCmmTop CmmStatic info graph
566 mkRODataLits lbl lits
567 = CmmData section (CmmDataLabel lbl : map CmmStaticLit lits)
568 where section | any needsRelocation lits = RelocatableReadOnlyData
569 | otherwise = ReadOnlyData
570 needsRelocation (CmmLabel _) = True
571 needsRelocation (CmmLabelOff _ _) = True
572 needsRelocation _ = False
574 mkStringCLit :: String -> FCode CmmLit
575 -- Make a global definition for the string,
576 -- and return its label
577 mkStringCLit str = mkByteStringCLit (map (fromIntegral.ord) str)
579 mkByteStringCLit :: [Word8] -> FCode CmmLit
580 mkByteStringCLit bytes
581 = do { uniq <- newUnique
582 ; let lbl = mkStringLitLabel uniq
583 ; emitData ReadOnlyData [CmmDataLabel lbl, CmmString bytes]
584 ; return (CmmLabel lbl) }
586 -------------------------------------------------------------------------
588 -- Assigning expressions to temporaries
590 -------------------------------------------------------------------------
592 -- | If the expression is trivial, return it. Otherwise, assign the
593 -- expression to a temporary register and return an expression
594 -- referring to this register.
595 assignTemp :: CmmExpr -> FCode CmmExpr
596 -- For a non-trivial expression, e, create a local
597 -- variable and assign the expression to it
599 | isTrivialCmmExpr e = return e
600 | otherwise = do { reg <- newTemp (cmmExprType e)
601 ; stmtC (CmmAssign (CmmLocal reg) e)
602 ; return (CmmReg (CmmLocal reg)) }
604 -- | If the expression is trivial and doesn't refer to a global
605 -- register, return it. Otherwise, assign the expression to a
606 -- temporary register and return an expression referring to this
608 assignTemp_ :: CmmExpr -> FCode CmmExpr
610 | isTrivialCmmExpr e && hasNoGlobalRegs e = return e
612 reg <- newTemp (cmmExprType e)
613 stmtC (CmmAssign (CmmLocal reg) e)
614 return (CmmReg (CmmLocal reg))
616 newTemp :: CmmType -> FCode LocalReg
617 newTemp rep = do { uniq <- newUnique; return (LocalReg uniq rep) }
619 -------------------------------------------------------------------------
621 -- Building case analysis
623 -------------------------------------------------------------------------
626 :: CmmExpr -- Tag to switch on
627 -> [(ConTagZ, CgStmts)] -- Tagged branches
628 -> Maybe CgStmts -- Default branch (if any)
629 -> ConTagZ -> ConTagZ -- Min and Max possible values; behaviour
630 -- outside this range is undefined
633 -- ONLY A DEFAULT BRANCH: no case analysis to do
634 emitSwitch tag_expr [] (Just stmts) _ _
638 emitSwitch tag_expr branches mb_deflt lo_tag hi_tag
639 = -- Just sort the branches before calling mk_sritch
642 Nothing -> return Nothing
643 Just stmts -> do id <- forkCgStmts stmts; return (Just id)
645 ; dflags <- getDynFlags
646 ; let via_C | HscC <- hscTarget dflags = True
649 ; stmts <- mk_switch tag_expr (sortLe le branches)
650 mb_deflt_id lo_tag hi_tag via_C
654 (t1,_) `le` (t2,_) = t1 <= t2
657 mk_switch :: CmmExpr -> [(ConTagZ, CgStmts)]
658 -> Maybe BlockId -> ConTagZ -> ConTagZ -> Bool
661 -- SINGLETON TAG RANGE: no case analysis to do
662 mk_switch tag_expr [(tag,stmts)] _ lo_tag hi_tag via_C
664 = ASSERT( tag == lo_tag )
667 -- SINGLETON BRANCH, NO DEFUALT: no case analysis to do
668 mk_switch tag_expr [(tag,stmts)] Nothing lo_tag hi_tag via_C
670 -- The simplifier might have eliminated a case
671 -- so we may have e.g. case xs of
673 -- In that situation we can be sure the (:) case
674 -- can't happen, so no need to test
676 -- SINGLETON BRANCH: one equality check to do
677 mk_switch tag_expr [(tag,stmts)] (Just deflt) lo_tag hi_tag via_C
678 = return (CmmCondBranch cond deflt `consCgStmt` stmts)
680 cond = cmmNeWord tag_expr (CmmLit (mkIntCLit tag))
681 -- We have lo_tag < hi_tag, but there's only one branch,
682 -- so there must be a default
684 -- ToDo: we might want to check for the two branch case, where one of
685 -- the branches is the tag 0, because comparing '== 0' is likely to be
686 -- more efficient than other kinds of comparison.
688 -- DENSE TAG RANGE: use a switch statment.
690 -- We also use a switch uncoditionally when compiling via C, because
691 -- this will get emitted as a C switch statement and the C compiler
692 -- should do a good job of optimising it. Also, older GCC versions
693 -- (2.95 in particular) have problems compiling the complicated
694 -- if-trees generated by this code, so compiling to a switch every
695 -- time works around that problem.
697 mk_switch tag_expr branches mb_deflt lo_tag hi_tag via_C
698 | use_switch -- Use a switch
699 = do { branch_ids <- mapM forkCgStmts (map snd branches)
701 tagged_blk_ids = zip (map fst branches) (map Just branch_ids)
703 find_branch :: ConTagZ -> Maybe BlockId
704 find_branch i = assocDefault mb_deflt tagged_blk_ids i
706 -- NB. we have eliminated impossible branches at
707 -- either end of the range (see below), so the first
708 -- tag of a real branch is real_lo_tag (not lo_tag).
709 arms = [ find_branch i | i <- [real_lo_tag..real_hi_tag]]
711 switch_stmt = CmmSwitch (cmmOffset tag_expr (- real_lo_tag)) arms
713 ; ASSERT(not (all isNothing arms))
714 return (oneCgStmt switch_stmt)
717 -- if we can knock off a bunch of default cases with one if, then do so
718 | Just deflt <- mb_deflt, (lowest_branch - lo_tag) >= n_branches
719 = do { (assign_tag, tag_expr') <- assignTemp' tag_expr
720 ; let cond = cmmULtWord tag_expr' (CmmLit (mkIntCLit lowest_branch))
721 branch = CmmCondBranch cond deflt
722 ; stmts <- mk_switch tag_expr' branches mb_deflt
723 lowest_branch hi_tag via_C
724 ; return (assign_tag `consCgStmt` (branch `consCgStmt` stmts))
727 | Just deflt <- mb_deflt, (hi_tag - highest_branch) >= n_branches
728 = do { (assign_tag, tag_expr') <- assignTemp' tag_expr
729 ; let cond = cmmUGtWord tag_expr' (CmmLit (mkIntCLit highest_branch))
730 branch = CmmCondBranch cond deflt
731 ; stmts <- mk_switch tag_expr' branches mb_deflt
732 lo_tag highest_branch via_C
733 ; return (assign_tag `consCgStmt` (branch `consCgStmt` stmts))
736 | otherwise -- Use an if-tree
737 = do { (assign_tag, tag_expr') <- assignTemp' tag_expr
738 -- To avoid duplication
739 ; lo_stmts <- mk_switch tag_expr' lo_branches mb_deflt
740 lo_tag (mid_tag-1) via_C
741 ; hi_stmts <- mk_switch tag_expr' hi_branches mb_deflt
743 ; hi_id <- forkCgStmts hi_stmts
744 ; let cond = cmmUGeWord tag_expr' (CmmLit (mkIntCLit mid_tag))
745 branch_stmt = CmmCondBranch cond hi_id
746 ; return (assign_tag `consCgStmt` (branch_stmt `consCgStmt` lo_stmts))
748 -- we test (e >= mid_tag) rather than (e < mid_tag), because
749 -- the former works better when e is a comparison, and there
750 -- are two tags 0 & 1 (mid_tag == 1). In this case, the code
751 -- generator can reduce the condition to e itself without
752 -- having to reverse the sense of the comparison: comparisons
753 -- can't always be easily reversed (eg. floating
756 use_switch = {- pprTrace "mk_switch" (
757 ppr tag_expr <+> text "n_tags:" <+> int n_tags <+>
758 text "branches:" <+> ppr (map fst branches) <+>
759 text "n_branches:" <+> int n_branches <+>
760 text "lo_tag:" <+> int lo_tag <+>
761 text "hi_tag:" <+> int hi_tag <+>
762 text "real_lo_tag:" <+> int real_lo_tag <+>
763 text "real_hi_tag:" <+> int real_hi_tag) $ -}
764 ASSERT( n_branches > 1 && n_tags > 1 )
765 n_tags > 2 && (via_C || (dense && big_enough))
766 -- up to 4 branches we use a decision tree, otherwise
767 -- a switch (== jump table in the NCG). This seems to be
768 -- optimal, and corresponds with what gcc does.
769 big_enough = n_branches > 4
770 dense = n_branches > (n_tags `div` 2)
771 n_branches = length branches
773 -- ignore default slots at each end of the range if there's
774 -- no default branch defined.
775 lowest_branch = fst (head branches)
776 highest_branch = fst (last branches)
779 | isNothing mb_deflt = lowest_branch
783 | isNothing mb_deflt = highest_branch
786 n_tags = real_hi_tag - real_lo_tag + 1
788 -- INVARIANT: Provided hi_tag > lo_tag (which is true)
789 -- lo_tag <= mid_tag < hi_tag
790 -- lo_branches have tags < mid_tag
791 -- hi_branches have tags >= mid_tag
793 (mid_tag,_) = branches !! (n_branches `div` 2)
794 -- 2 branches => n_branches `div` 2 = 1
795 -- => branches !! 1 give the *second* tag
796 -- There are always at least 2 branches here
798 (lo_branches, hi_branches) = span is_lo branches
799 is_lo (t,_) = t < mid_tag
803 | isTrivialCmmExpr e = return (CmmNop, e)
804 | otherwise = do { reg <- newTemp (cmmExprType e)
805 ; return (CmmAssign (CmmLocal reg) e, CmmReg (CmmLocal reg)) }
807 emitLitSwitch :: CmmExpr -- Tag to switch on
808 -> [(Literal, CgStmts)] -- Tagged branches
809 -> CgStmts -- Default branch (always)
810 -> Code -- Emit the code
811 -- Used for general literals, whose size might not be a word,
812 -- where there is always a default case, and where we don't know
813 -- the range of values for certain. For simplicity we always generate a tree.
815 -- ToDo: for integers we could do better here, perhaps by generalising
816 -- mk_switch and using that. --SDM 15/09/2004
817 emitLitSwitch scrut [] deflt
819 emitLitSwitch scrut branches deflt_blk
820 = do { scrut' <- assignTemp scrut
821 ; deflt_blk_id <- forkCgStmts deflt_blk
822 ; blk <- mk_lit_switch scrut' deflt_blk_id (sortLe le branches)
825 le (t1,_) (t2,_) = t1 <= t2
827 mk_lit_switch :: CmmExpr -> BlockId
828 -> [(Literal,CgStmts)]
830 mk_lit_switch scrut deflt_blk_id [(lit,blk)]
831 = return (consCgStmt if_stmt blk)
833 cmm_lit = mkSimpleLit lit
834 rep = cmmLitType cmm_lit
835 ne = if isFloatType rep then MO_F_Ne else MO_Ne
836 cond = CmmMachOp (ne (typeWidth rep)) [scrut, CmmLit cmm_lit]
837 if_stmt = CmmCondBranch cond deflt_blk_id
839 mk_lit_switch scrut deflt_blk_id branches
840 = do { hi_blk <- mk_lit_switch scrut deflt_blk_id hi_branches
841 ; lo_blk <- mk_lit_switch scrut deflt_blk_id lo_branches
842 ; lo_blk_id <- forkCgStmts lo_blk
843 ; let if_stmt = CmmCondBranch cond lo_blk_id
844 ; return (if_stmt `consCgStmt` hi_blk) }
846 n_branches = length branches
847 (mid_lit,_) = branches !! (n_branches `div` 2)
848 -- See notes above re mid_tag
850 (lo_branches, hi_branches) = span is_lo branches
851 is_lo (t,_) = t < mid_lit
853 cond = CmmMachOp (mkLtOp mid_lit)
854 [scrut, CmmLit (mkSimpleLit mid_lit)]
856 -------------------------------------------------------------------------
858 -- Simultaneous assignment
860 -------------------------------------------------------------------------
863 emitSimultaneously :: CmmStmts -> Code
864 -- Emit code to perform the assignments in the
865 -- input simultaneously, using temporary variables when necessary.
867 -- The Stmts must be:
868 -- CmmNop, CmmComment, CmmAssign, CmmStore
872 -- We use the strongly-connected component algorithm, in which
873 -- * the vertices are the statements
874 -- * an edge goes from s1 to s2 iff
875 -- s1 assigns to something s2 uses
876 -- that is, if s1 should *follow* s2 in the final order
878 type CVertex = (Int, CmmStmt) -- Give each vertex a unique number,
879 -- for fast comparison
881 emitSimultaneously stmts
883 case filterOut isNopStmt (stmtList stmts) of
886 [stmt] -> stmtC stmt -- It's often just one stmt
887 stmt_list -> doSimultaneously1 (zip [(1::Int)..] stmt_list)
889 doSimultaneously1 :: [CVertex] -> Code
890 doSimultaneously1 vertices
892 edges = [ (vertex, key1, edges_from stmt1)
893 | vertex@(key1, stmt1) <- vertices
895 edges_from stmt1 = [ key2 | (key2, stmt2) <- vertices,
896 stmt1 `mustFollow` stmt2
898 components = stronglyConnCompFromEdgedVertices edges
900 -- do_components deal with one strongly-connected component
901 -- Not cyclic, or singleton? Just do it
902 do_component (AcyclicSCC (n,stmt)) = stmtC stmt
903 do_component (CyclicSCC [(n,stmt)]) = stmtC stmt
905 -- Cyclic? Then go via temporaries. Pick one to
906 -- break the loop and try again with the rest.
907 do_component (CyclicSCC ((n,first_stmt) : rest))
908 = do { from_temp <- go_via_temp first_stmt
909 ; doSimultaneously1 rest
912 go_via_temp (CmmAssign dest src)
913 = do { tmp <- newTemp (cmmRegType dest) -- TODO FIXME NOW if the pair of assignments move across a call this will be wrong
914 ; stmtC (CmmAssign (CmmLocal tmp) src)
915 ; return (CmmAssign dest (CmmReg (CmmLocal tmp))) }
916 go_via_temp (CmmStore dest src)
917 = do { tmp <- newTemp (cmmExprType src) -- TODO FIXME NOW if the pair of assignemnts move across a call this will be wrong
918 ; stmtC (CmmAssign (CmmLocal tmp) src)
919 ; return (CmmStore dest (CmmReg (CmmLocal tmp))) }
921 mapCs do_component components
923 mustFollow :: CmmStmt -> CmmStmt -> Bool
924 CmmAssign reg _ `mustFollow` stmt = anySrc (reg `regUsedIn`) stmt
925 CmmStore loc e `mustFollow` stmt = anySrc (locUsedIn loc (cmmExprType e)) stmt
926 CmmNop `mustFollow` stmt = False
927 CmmComment _ `mustFollow` stmt = False
930 anySrc :: (CmmExpr -> Bool) -> CmmStmt -> Bool
931 -- True if the fn is true of any input of the stmt
932 anySrc p (CmmAssign _ e) = p e
933 anySrc p (CmmStore e1 e2) = p e1 || p e2 -- Might be used in either side
934 anySrc p (CmmComment _) = False
935 anySrc p CmmNop = False
936 anySrc p other = True -- Conservative
938 locUsedIn :: CmmExpr -> CmmType -> CmmExpr -> Bool
939 -- (locUsedIn a r e) checks whether writing to r[a] could affect the value of
940 -- 'e'. Returns True if it's not sure.
941 locUsedIn loc rep (CmmLit _) = False
942 locUsedIn loc rep (CmmLoad e ld_rep) = possiblySameLoc loc rep e ld_rep
943 locUsedIn loc rep (CmmReg reg') = False
944 locUsedIn loc rep (CmmRegOff reg' _) = False
945 locUsedIn loc rep (CmmMachOp _ es) = any (locUsedIn loc rep) es
947 possiblySameLoc :: CmmExpr -> CmmType -> CmmExpr -> CmmType -> Bool
948 -- Assumes that distinct registers (eg Hp, Sp) do not
949 -- point to the same location, nor any offset thereof.
950 possiblySameLoc (CmmReg r1) rep1 (CmmReg r2) rep2 = r1==r2
951 possiblySameLoc (CmmReg r1) rep1 (CmmRegOff r2 0) rep2 = r1==r2
952 possiblySameLoc (CmmRegOff r1 0) rep1 (CmmReg r2) rep2 = r1==r2
953 possiblySameLoc (CmmRegOff r1 start1) rep1 (CmmRegOff r2 start2) rep2
954 = r1==r2 && end1 > start2 && end2 > start1
956 end1 = start1 + widthInBytes (typeWidth rep1)
957 end2 = start2 + widthInBytes (typeWidth rep2)
959 possiblySameLoc l1 rep1 (CmmLit _) rep2 = False
960 possiblySameLoc l1 rep1 l2 rep2 = True -- Conservative
962 -------------------------------------------------------------------------
964 -- Static Reference Tables
966 -------------------------------------------------------------------------
968 -- There is just one SRT for each top level binding; all the nested
969 -- bindings use sub-sections of this SRT. The label is passed down to
970 -- the nested bindings via the monad.
972 getSRTInfo :: FCode C_SRT
974 srt_lbl <- getSRTLabel
977 -- TODO: Should we panic in this case?
978 -- Someone obviously thinks there should be an SRT
979 NoSRT -> return NoC_SRT
980 SRTEntries {} -> panic "getSRTInfo: SRTEntries. Perhaps you forgot to run SimplStg?"
982 | len > hALF_WORD_SIZE_IN_BITS || bmp == [fromIntegral srt_escape]
983 -> do id <- newUnique
984 let srt_desc_lbl = mkLargeSRTLabel id
985 emitRODataLits "getSRTInfo" srt_desc_lbl
986 ( cmmLabelOffW srt_lbl off
987 : mkWordCLit (fromIntegral len)
988 : map mkWordCLit bmp)
989 return (C_SRT srt_desc_lbl 0 srt_escape)
993 -> return (C_SRT srt_lbl off (fromIntegral (head bmp)))
994 -- The fromIntegral converts to StgHalfWord
996 srt_escape = (-1) :: StgHalfWord
998 clHasCafRefs :: ClosureInfo -> CafInfo
999 clHasCafRefs (ClosureInfo {closureSRT = srt}) =
1000 case srt of NoC_SRT -> NoCafRefs
1002 clHasCafRefs (ConInfo {}) = NoCafRefs
1004 -- -----------------------------------------------------------------------------
1006 -- STG/Cmm GlobalReg
1008 -- -----------------------------------------------------------------------------
1010 -- | Here is where the STG register map is defined for each target arch.
1011 -- The order matters (for the llvm backend anyway)! We must make sure to
1012 -- maintain the order here with the order used in the LLVM calling conventions.
1013 -- Note that also, this isn't all registers, just the ones that are currently
1014 -- possbily mapped to real registers.
1015 activeStgRegs :: [GlobalReg]
1027 ,VanillaReg 1 VGcPtr
1030 ,VanillaReg 2 VGcPtr
1033 ,VanillaReg 3 VGcPtr
1036 ,VanillaReg 4 VGcPtr
1039 ,VanillaReg 5 VGcPtr
1042 ,VanillaReg 6 VGcPtr
1045 ,VanillaReg 7 VGcPtr
1048 ,VanillaReg 8 VGcPtr
1073 -- | We map STG registers onto appropriate CmmExprs. Either they map
1074 -- to real machine registers or stored as offsets from BaseReg. Given
1075 -- a GlobalReg, get_GlobalReg_addr always produces the
1076 -- register table address for it.
1077 get_GlobalReg_addr :: GlobalReg -> CmmExpr
1078 get_GlobalReg_addr BaseReg = regTableOffset 0
1079 get_GlobalReg_addr mid = get_Regtable_addr_from_offset
1080 (globalRegType mid) (baseRegOffset mid)
1082 -- Calculate a literal representing an offset into the register table.
1083 -- Used when we don't have an actual BaseReg to offset from.
1085 CmmLit (CmmLabelOff mkMainCapabilityLabel (oFFSET_Capability_r + n))
1087 get_Regtable_addr_from_offset :: CmmType -> Int -> CmmExpr
1088 get_Regtable_addr_from_offset rep offset =
1090 CmmRegOff (CmmGlobal BaseReg) offset
1092 regTableOffset offset
1095 -- | Fixup global registers so that they assign to locations within the
1096 -- RegTable if they aren't pinned for the current target.
1097 fixStgRegisters :: RawCmmTop -> RawCmmTop
1098 fixStgRegisters top@(CmmData _ _) = top
1100 fixStgRegisters (CmmProc info lbl (ListGraph blocks)) =
1101 let blocks' = map fixStgRegBlock blocks
1102 in CmmProc info lbl $ ListGraph blocks'
1104 fixStgRegBlock :: CmmBasicBlock -> CmmBasicBlock
1105 fixStgRegBlock (BasicBlock id stmts) =
1106 let stmts' = map fixStgRegStmt stmts
1107 in BasicBlock id stmts'
1109 fixStgRegStmt :: CmmStmt -> CmmStmt
1112 CmmAssign (CmmGlobal reg) src ->
1113 let src' = fixStgRegExpr src
1114 baseAddr = get_GlobalReg_addr reg
1115 in case reg `elem` activeStgRegs of
1116 True -> CmmAssign (CmmGlobal reg) src'
1117 False -> CmmStore baseAddr src'
1119 CmmAssign reg src ->
1120 let src' = fixStgRegExpr src
1121 in CmmAssign reg src'
1123 CmmStore addr src -> CmmStore (fixStgRegExpr addr) (fixStgRegExpr src)
1125 CmmCall target regs args srt returns ->
1126 let target' = case target of
1127 CmmCallee e conv -> CmmCallee (fixStgRegExpr e) conv
1129 args' = map (\(CmmHinted arg hint) ->
1130 (CmmHinted (fixStgRegExpr arg) hint)) args
1131 in CmmCall target' regs args' srt returns
1133 CmmCondBranch test dest -> CmmCondBranch (fixStgRegExpr test) dest
1135 CmmSwitch expr ids -> CmmSwitch (fixStgRegExpr expr) ids
1137 CmmJump addr regs -> CmmJump (fixStgRegExpr addr) regs
1139 -- CmmNop, CmmComment, CmmBranch, CmmReturn
1143 fixStgRegExpr :: CmmExpr -> CmmExpr
1146 CmmLoad addr ty -> CmmLoad (fixStgRegExpr addr) ty
1148 CmmMachOp mop args -> CmmMachOp mop args'
1149 where args' = map fixStgRegExpr args
1151 CmmReg (CmmGlobal reg) ->
1152 -- Replace register leaves with appropriate StixTrees for
1153 -- the given target. MagicIds which map to a reg on this
1154 -- arch are left unchanged. For the rest, BaseReg is taken
1155 -- to mean the address of the reg table in MainCapability,
1156 -- and for all others we generate an indirection to its
1157 -- location in the register table.
1158 case reg `elem` activeStgRegs of
1161 let baseAddr = get_GlobalReg_addr reg
1163 BaseReg -> fixStgRegExpr baseAddr
1164 _other -> fixStgRegExpr
1165 (CmmLoad baseAddr (globalRegType reg))
1167 CmmRegOff (CmmGlobal reg) offset ->
1168 -- RegOf leaves are just a shorthand form. If the reg maps
1169 -- to a real reg, we keep the shorthand, otherwise, we just
1170 -- expand it and defer to the above code.
1171 case reg `elem` activeStgRegs of
1173 False -> fixStgRegExpr (CmmMachOp (MO_Add wordWidth) [
1174 CmmReg (CmmGlobal reg),
1175 CmmLit (CmmInt (fromIntegral offset)
1178 -- CmmLit, CmmReg (CmmLocal), CmmStackSlot