1 module CmmBuildInfoTables
2 ( CAFSet, CAFEnv, CmmTopForInfoTables(..), cafAnal, localCAFInfo, mkTopCAFInfo
3 , setInfoTableSRT, setInfoTableStackMap
4 , TopSRT, emptySRT, srtToData
6 , finishInfoTables, lowerSafeForeignCalls, extendEnvsForSafeForeignCalls )
9 #include "HsVersions.h"
13 import qualified Prelude as P
20 import Cmm hiding (blockId)
34 import MkZipCfgCmm hiding (CmmAGraph, CmmBlock, CmmTopZ, CmmZ, CmmGraph)
45 import ZipCfg hiding (zip, unzip, last)
46 import qualified ZipCfg as G
50 ----------------------------------------------------------------
51 -- Building InfoTables
54 -----------------------------------------------------------------------
57 -- Given a block ID, we return a representation of the layout of the stack,
58 -- as suspended before entering that block.
59 -- (For a return site to a function call, the layout does not include the
60 -- parameter passing area (or the "return address" on the stack)).
61 -- If the element is `Nothing`, then it represents a word of the stack that
62 -- does not contain a live pointer.
63 -- If the element is `Just` a register, then it represents a live spill slot
64 -- for a pointer; we assume that a pointer is the size of a word.
65 -- The head of the list represents the young end of the stack where the infotable
66 -- pointer for the block `Bid` is stored.
67 -- The infotable pointer itself is not included in the list.
68 -- Call areas are also excluded from the list: besides the stuff in the update
69 -- frame (and the return infotable), call areas should never be live across
72 -- RTS Invariant: All pointers must be word-aligned because each bit in the bitmap
73 -- represents a word. Consequently, we have to be careful when we see a live slot
74 -- on the stack: if we have packed multiple sub-word values into a word,
75 -- we have to make sure that we only mark the entire word as a non-pointer.
77 -- Also, don't forget to stop at the old end of the stack (oldByte),
78 -- which may differ depending on whether there is an update frame.
79 live_ptrs :: ByteOff -> BlockEnv SubAreaSet -> AreaMap -> BlockId -> [Maybe LocalReg]
80 live_ptrs oldByte slotEnv areaMap bid =
81 -- pprTrace "live_ptrs for" (ppr bid <+> ppr youngByte <+> ppr liveSlots) $
82 reverse $ slotsToList youngByte liveSlots []
83 where slotsToList n [] results | n == oldByte = results -- at old end of stack frame
84 slotsToList n (s : _) _ | n == oldByte =
85 pprPanic "slot left off live_ptrs" (ppr s <+> ppr oldByte <+>
86 ppr n <+> ppr liveSlots <+> ppr youngByte)
87 slotsToList n _ _ | n < oldByte =
88 panic "stack slots not allocated on word boundaries?"
89 slotsToList n l@((n', r, w) : rst) results =
90 if n == (n' + w) then -- slot's young byte is at n
91 ASSERT (not (isPtr r) ||
92 (n `mod` wORD_SIZE == 0 && w == wORD_SIZE)) -- ptrs must be aligned
93 slotsToList next (dropWhile (non_ptr_younger_than next) rst)
95 else slotsToList next (dropWhile (non_ptr_younger_than next) l)
97 where next = n - wORD_SIZE
98 stack_rep = if isPtr r then Just r else Nothing
99 slotsToList n [] results = slotsToList (n - wORD_SIZE) [] (Nothing : results)
100 non_ptr_younger_than next (n', r, w) =
102 ASSERT (not (isPtr r))
104 isPtr = isGcPtrType . localRegType
105 liveSlots = sortBy (\ (off,_,_) (off',_,_) -> compare off' off)
106 (foldFM (\_ -> flip $ foldl add_slot) [] slots)
108 add_slot rst (a@(RegSlot r@(LocalReg _ ty)), off, w) =
109 if off == w && widthInBytes (typeWidth ty) == w then
110 (expectJust "add_slot" (lookupFM areaMap a), r, w) : rst
111 else panic "live_ptrs: only part of a variable live at a proc point"
112 add_slot rst (CallArea Old, _, _) =
113 rst -- the update frame (or return infotable) should be live
114 -- would be nice to check that only that part of the callarea is live...
115 add_slot rst ((CallArea _), _, _) =
117 -- JD: THIS ISN'T CURRENTLY A CORRECTNESS PROBLEM, BUT WE SHOULD REALLY
118 -- MAKE LIVENESS INFO AROUND CALLS MORE PRECISE -- FOR NOW, A 32-BIT
119 -- FLOAT PADS OUT TO 64 BITS, BUT WE ASSUME THE WHOLE PARAMETER-PASSING
120 -- AREA IS LIVE (WHICH IT ISN'T...). WE SHOULD JUST PUT THE LIVE AREAS
121 -- IN THE CALL NODES, WHICH SHOULD EVENTUALLY HAVE LIVE REGISTER AS WELL,
122 -- SO IT'S ALL GOING IN THE SAME DIRECTION.
123 -- pprPanic "CallAreas must not be live across function calls" (ppr bid <+> ppr c)
124 slots = expectJust "live_ptrs slots" $ lookupBlockEnv slotEnv bid
125 youngByte = expectJust "live_ptrs bid_pos" $ lookupFM areaMap (CallArea (Young bid))
127 -- Construct the stack maps for the given procedure.
128 setInfoTableStackMap :: SlotEnv -> AreaMap -> CmmTopForInfoTables -> CmmTopForInfoTables
129 setInfoTableStackMap _ _ t@(NoInfoTable _) = t
130 setInfoTableStackMap slotEnv areaMap t@(FloatingInfoTable _ bid updfr_off) =
131 updInfo (const (live_ptrs updfr_off slotEnv areaMap bid)) id t
132 setInfoTableStackMap slotEnv areaMap
133 t@(ProcInfoTable (CmmProc (CmmInfo _ _ infoTbl) _ _ g@(LGraph _ _ blocks))
135 case blockSetToList procpoints of
137 let oldByte = case infoTbl of
138 CmmInfoTable _ _ _ (ContInfo _ _) ->
139 case lookupBlockEnv blocks bid of
140 Just (Block _ (StackInfo {returnOff = Just n}) _) -> n
141 _ -> pprPanic "misformed graph at procpoint" (ppr g)
142 _ -> initUpdFrameOff -- entry to top-level function
143 stack_vars = live_ptrs oldByte slotEnv areaMap bid
144 in updInfo (const stack_vars) id t
145 _ -> panic "setInfoTableStackMap: unexpect number of procpoints"
146 -- until we stop splitting the graphs at procpoints in the native path
147 setInfoTableStackMap _ _ _ = panic "unexpected case for setInfoTableStackMap"
149 setInfoTableStackMap slotEnv areaMap
150 (Just bid, p@(CmmProc (CmmInfo _ _ infoTbl) _ _ g@(LGraph entry _ blocks))) =
151 let oldByte = case infoTbl of
152 CmmInfoTable _ _ _ (ContInfo _ _) ->
153 case lookupBlockEnv blocks bid of
154 Just (Block _ (StackInfo {returnOff = Just n}) _) -> n
155 _ -> pprPanic "misformed graph at procpoint" (ppr g)
156 _ -> initUpdFrameOff -- entry to top-level function
157 stack_vars = live_ptrs oldByte slotEnv areaMap bid
158 in (Just bid, upd_info_tbl (const stack_vars) id p)
159 setInfoTableStackMap _ _ t@(_, CmmData {}) = t
160 setInfoTableStackMap _ _ _ = panic "bad args to setInfoTableStackMap"
164 -----------------------------------------------------------------------
167 -- WE NEED AN EXAMPLE HERE.
168 -- IN PARTICULAR, WE NEED TO POINT OUT THE DISTINCTION BETWEEN
169 -- FUNCTIONS WITH STATIC CLOSURES AND THOSE THAT MUST BE CONSTRUCTED
170 -- DYNAMICALLY (AND HENCE CAN'T BE REFERENCED IN AN SRT).
171 -- IN THE LATTER CASE, WE HAVE TO TAKE ALL THE CAFs REFERENCED BY
172 -- THE CLOSURE AND INLINE THEM INTO ANY SRT THAT MAY MENTION THE CLOSURE.
173 -- (I.E. TAKE THE TRANSITIVE CLOSURE, but only for non-static closures).
176 -----------------------------------------------------------------------
177 -- Finding the CAFs used by a procedure
179 type CAFSet = FiniteMap CLabel ()
180 type CAFEnv = BlockEnv CAFSet
182 -- First, an analysis to find live CAFs.
183 cafLattice :: DataflowLattice CAFSet
184 cafLattice = DataflowLattice "live cafs" emptyFM add False
185 where add new old = if sizeFM new' > sizeFM old then aTx new' else noTx new'
186 where new' = new `plusFM` old
188 cafTransfers :: BackwardTransfers Middle Last CAFSet
189 cafTransfers = BackwardTransfers first middle last
190 where first live _ = live
191 middle live m = foldExpDeepMiddle addCaf m live
192 last env l = foldExpDeepLast addCaf l (joinOuts cafLattice env l)
193 addCaf e set = case e of
194 CmmLit (CmmLabel c) -> add c set
195 CmmLit (CmmLabelOff c _) -> add c set
196 CmmLit (CmmLabelDiffOff c1 c2 _) -> add c1 $ add c2 set
198 add l s = if hasCAF l then addToFM s (cvtToClosureLbl l) () else s
200 type CafFix a = FuelMonad (BackwardFixedPoint Middle Last CAFSet a)
201 cafAnal :: LGraph Middle Last -> FuelMonad CAFEnv
202 cafAnal g = liftM zdfFpFacts (res :: CafFix ())
203 where res = zdfSolveFromL emptyBlockEnv "live CAF analysis" cafLattice
204 cafTransfers (fact_bot cafLattice) g
206 -----------------------------------------------------------------------
209 -- Description of the SRT for a given module.
210 -- Note that this SRT may grow as we greedily add new CAFs to it.
211 data TopSRT = TopSRT { lbl :: CLabel
212 , next_elt :: Int -- the next entry in the table
213 , rev_elts :: [CLabel]
214 , elt_map :: FiniteMap CLabel Int }
215 -- map: CLabel -> its last entry in the table
216 instance Outputable TopSRT where
217 ppr (TopSRT lbl next elts eltmap) =
218 text "TopSRT:" <+> ppr lbl <+> ppr next <+> ppr elts <+> ppr eltmap
220 emptySRT :: MonadUnique m => m TopSRT
222 do top_lbl <- getUniqueM >>= \ u -> return $ mkSRTLabel (mkFCallName u "srt") NoCafRefs
223 return TopSRT { lbl = top_lbl, next_elt = 0, rev_elts = [], elt_map = emptyFM }
225 cafMember :: TopSRT -> CLabel -> Bool
226 cafMember srt lbl = elemFM lbl (elt_map srt)
228 cafOffset :: TopSRT -> CLabel -> Maybe Int
229 cafOffset srt lbl = lookupFM (elt_map srt) lbl
231 addCAF :: CLabel -> TopSRT -> TopSRT
233 srt { next_elt = last + 1
234 , rev_elts = caf : rev_elts srt
235 , elt_map = addToFM (elt_map srt) caf last }
236 where last = next_elt srt
238 srtToData :: TopSRT -> CmmZ
239 srtToData srt = Cmm [CmmData RelocatableReadOnlyData (CmmDataLabel (lbl srt) : tbl)]
240 where tbl = map (CmmStaticLit . CmmLabel) (reverse (rev_elts srt))
242 -- Once we have found the CAFs, we need to do two things:
243 -- 1. Build a table of all the CAFs used in the procedure.
244 -- 2. Compute the C_SRT describing the subset of CAFs live at each procpoint.
246 -- When building the local view of the SRT, we first make sure that all the CAFs are
247 -- in the SRT. Then, if the number of CAFs is small enough to fit in a bitmap,
248 -- we make sure they're all close enough to the bottom of the table that the
249 -- bitmap will be able to cover all of them.
250 buildSRTs :: TopSRT -> FiniteMap CLabel CAFSet -> CAFSet ->
251 FuelMonad (TopSRT, Maybe CmmTopZ, C_SRT)
252 buildSRTs topSRT topCAFMap cafs =
253 do let liftCAF lbl () z = -- get CAFs for functions without static closures
254 case lookupFM topCAFMap lbl of Just cafs -> z `plusFM` cafs
255 Nothing -> addToFM z lbl ()
256 sub_srt topSRT localCafs =
257 let cafs = keysFM (foldFM liftCAF emptyFM localCafs)
259 do localSRTs <- procpointSRT (lbl topSRT) (elt_map topSRT) cafs
260 return (topSRT, localSRTs)
261 in if length cafs > maxBmpSize then
262 mkSRT (foldl add_if_missing topSRT cafs)
263 else -- make sure all the cafs are near the bottom of the srt
264 mkSRT (add_if_too_far topSRT cafs)
265 add_if_missing srt caf =
266 if cafMember srt caf then srt else addCAF caf srt
267 -- If a CAF is more than maxBmpSize entries from the young end of the
268 -- SRT, then we add it to the SRT again.
269 -- (Note: Not in the SRT => infinitely far.)
270 add_if_too_far srt@(TopSRT {elt_map = m}) cafs =
271 add srt (sortBy farthestFst cafs)
273 farthestFst x y = case (lookupFM m x, lookupFM m y) of
274 (Nothing, Nothing) -> EQ
275 (Nothing, Just _) -> LT
276 (Just _, Nothing) -> GT
277 (Just d, Just d') -> compare d' d
279 add srt@(TopSRT {next_elt = next}) (caf : rst) =
280 case cafOffset srt caf of
281 Just ix -> if next - ix > maxBmpSize then
282 add (addCAF caf srt) rst
284 Nothing -> add (addCAF caf srt) rst
285 (topSRT, subSRTs) <- sub_srt topSRT cafs
286 let (sub_tbls, blockSRTs) = subSRTs
287 return (topSRT, sub_tbls, blockSRTs)
289 -- Construct an SRT bitmap.
290 -- Adapted from simpleStg/SRT.lhs, which expects Id's.
291 procpointSRT :: CLabel -> FiniteMap CLabel Int -> [CLabel] ->
292 FuelMonad (Maybe CmmTopZ, C_SRT)
293 procpointSRT _ _ [] =
294 return (Nothing, NoC_SRT)
295 procpointSRT top_srt top_table entries =
296 do (top, srt) <- bitmap `seq` to_SRT top_srt offset len bitmap
299 ints = map (expectJust "constructSRT" . lookupFM top_table) entries
300 sorted_ints = sortLe (<=) ints
301 offset = head sorted_ints
302 bitmap_entries = map (subtract offset) sorted_ints
303 len = P.last bitmap_entries + 1
304 bitmap = intsToBitmap len bitmap_entries
307 maxBmpSize = widthInBits wordWidth `div` 2
309 -- Adapted from codeGen/StgCmmUtils, which converts from SRT to C_SRT.
310 to_SRT :: CLabel -> Int -> Int -> Bitmap -> FuelMonad (Maybe CmmTopZ, C_SRT)
311 to_SRT top_srt off len bmp
312 | len > maxBmpSize || bmp == [fromIntegral srt_escape]
313 = do id <- getUniqueM
314 let srt_desc_lbl = mkLargeSRTLabel id
315 tbl = CmmData RelocatableReadOnlyData $
316 CmmDataLabel srt_desc_lbl : map CmmStaticLit
317 ( cmmLabelOffW top_srt off
318 : mkWordCLit (fromIntegral len)
319 : map mkWordCLit bmp)
320 return (Just tbl, C_SRT srt_desc_lbl 0 srt_escape)
322 = return (Nothing, C_SRT top_srt off (fromIntegral (head bmp)))
323 -- The fromIntegral converts to StgHalfWord
325 -- Gather CAF info for a procedure, but only if the procedure
326 -- doesn't have a static closure.
327 -- (If it has a static closure, it will already have an SRT to
328 -- keep its CAFs live.)
329 -- Any procedure referring to a non-static CAF c must keep live the
330 -- any CAF that is reachable from c.
331 localCAFInfo :: CAFEnv -> CmmTopZ -> Maybe (CLabel, CAFSet)
332 localCAFInfo _ (CmmData _ _) = Nothing
333 localCAFInfo cafEnv (CmmProc (CmmInfo _ _ infoTbl) top_l _ (LGraph entry _ _)) =
335 CmmInfoTable False _ _ _ ->
336 Just (cvtToClosureLbl top_l,
337 expectJust "maybeBindCAFs" $ lookupBlockEnv cafEnv entry)
340 -- Once we have the local CAF sets for some (possibly) mutually
341 -- recursive functions, we can create an environment mapping
342 -- each function to its set of CAFs. Note that a CAF may
343 -- be a reference to a function. If that function f does not have
344 -- a static closure, then we need to refer specifically
345 -- to the set of CAFs used by f. Of course, the set of CAFs
346 -- used by f must be included in the local CAF sets that are input to
347 -- this function. To minimize lookup time later, we return
348 -- the environment with every reference to f replaced by its set of CAFs.
349 -- To do this replacement efficiently, we gather strongly connected
350 -- components, then we sort the components in topological order.
351 mkTopCAFInfo :: [(CLabel, CAFSet)] -> FiniteMap CLabel CAFSet
352 mkTopCAFInfo localCAFs = foldl addToTop emptyFM g
353 where addToTop env (AcyclicSCC (l, cafset)) =
354 addToFM env l (flatten env cafset)
355 addToTop env (CyclicSCC nodes) =
356 let (lbls, cafsets) = unzip nodes
357 cafset = foldl plusFM emptyFM cafsets `delListFromFM` lbls
358 in foldl (\env l -> addToFM env l (flatten env cafset)) env lbls
359 flatten env cafset = foldFM (lookup env) emptyFM cafset
360 lookup env caf () cafset' =
361 case lookupFM env caf of Just cafs -> foldFM add cafset' cafs
362 Nothing -> add caf () cafset'
363 add caf () cafset' = addToFM cafset' caf ()
364 g = stronglyConnCompFromEdgedVertices
365 (map (\n@(l, cafs) -> (n, l, keysFM cafs)) localCAFs)
367 type StackLayout = [Maybe LocalReg]
369 -- Bundle the CAFs used at a procpoint.
370 bundleCAFs :: CAFEnv -> CmmTopForInfoTables -> (CAFSet, CmmTopForInfoTables)
371 bundleCAFs cafEnv t@(ProcInfoTable _ procpoints) =
372 case blockSetToList procpoints of
373 [bid] -> (expectJust "bundleCAFs " (lookupBlockEnv cafEnv bid), t)
374 _ -> panic "setInfoTableStackMap: unexpect number of procpoints"
375 -- until we stop splitting the graphs at procpoints in the native path
376 bundleCAFs cafEnv t@(FloatingInfoTable _ bid _) =
377 (expectJust "bundleCAFs " (lookupBlockEnv cafEnv bid), t)
378 bundleCAFs _ t@(NoInfoTable _) = (emptyFM, t)
380 -- Construct the SRTs for the given procedure.
381 setInfoTableSRT :: FiniteMap CLabel CAFSet -> TopSRT -> (CAFSet, CmmTopForInfoTables) ->
382 FuelMonad (TopSRT, [CmmTopForInfoTables])
383 setInfoTableSRT topCAFMap topSRT (cafs, t@(ProcInfoTable _ procpoints)) =
384 case blockSetToList procpoints of
385 [_] -> setSRT cafs topCAFMap topSRT t
386 _ -> panic "setInfoTableStackMap: unexpect number of procpoints"
387 -- until we stop splitting the graphs at procpoints in the native path
388 setInfoTableSRT topCAFMap topSRT (cafs, t@(FloatingInfoTable _ _ _)) =
389 setSRT cafs topCAFMap topSRT t
390 setInfoTableSRT _ topSRT (_, t@(NoInfoTable _)) = return (topSRT, [t])
392 setSRT :: CAFSet -> FiniteMap CLabel CAFSet -> TopSRT ->
393 CmmTopForInfoTables -> FuelMonad (TopSRT, [CmmTopForInfoTables])
394 setSRT cafs topCAFMap topSRT t =
395 do (topSRT, cafTable, srt) <- buildSRTs topSRT topCAFMap cafs
396 let t' = updInfo id (const srt) t
398 Just tbl -> return (topSRT, [t', NoInfoTable tbl])
399 Nothing -> return (topSRT, [t'])
401 updInfo :: (StackLayout -> StackLayout) -> (C_SRT -> C_SRT) ->
402 CmmTopForInfoTables -> CmmTopForInfoTables
403 updInfo toVars toSrt (ProcInfoTable (CmmProc info top_l top_args g) procpoints) =
404 ProcInfoTable (CmmProc (updInfoTbl toVars toSrt info) top_l top_args g) procpoints
405 updInfo toVars toSrt (FloatingInfoTable info bid updfr_off) =
406 FloatingInfoTable (updInfoTbl toVars toSrt info) bid updfr_off
407 updInfo _ _ (NoInfoTable _) = panic "can't update NoInfoTable"
408 updInfo _ _ _ = panic "unexpected arg to updInfo"
410 updInfoTbl :: (StackLayout -> StackLayout) -> (C_SRT -> C_SRT) -> CmmInfo -> CmmInfo
411 updInfoTbl toVars toSrt (CmmInfo gc upd_fr (CmmInfoTable s p t typeinfo))
412 = CmmInfo gc upd_fr (CmmInfoTable s p t typeinfo')
413 where typeinfo' = case typeinfo of
414 t@(ConstrInfo _ _ _) -> t
415 (FunInfo c s a d e) -> FunInfo c (toSrt s) a d e
416 (ThunkInfo c s) -> ThunkInfo c (toSrt s)
417 (ThunkSelectorInfo x s) -> ThunkSelectorInfo x (toSrt s)
418 (ContInfo v s) -> ContInfo (toVars v) (toSrt s)
419 updInfoTbl _ _ t@(CmmInfo _ _ CmmNonInfoTable) = t
421 -- Lower the CmmTopForInfoTables type down to good old CmmTopZ
422 -- by emitting info tables as data where necessary.
423 finishInfoTables :: CmmTopForInfoTables -> IO [CmmTopZ]
424 finishInfoTables (NoInfoTable t) = return [t]
425 finishInfoTables (ProcInfoTable p _) = return [p]
426 finishInfoTables (FloatingInfoTable (CmmInfo _ _ infotbl) bid _) =
427 do uniq_supply <- mkSplitUniqSupply 'i'
428 return $ mkBareInfoTable (retPtLbl bid) (uniqFromSupply uniq_supply) infotbl
430 ----------------------------------------------------------------
431 -- Safe foreign calls:
432 -- Our analyses capture the dataflow facts at block boundaries, but we need
433 -- to extend the CAF and live-slot analyses to safe foreign calls as well,
434 -- which show up as middle nodes.
435 extendEnvsForSafeForeignCalls :: CAFEnv -> SlotEnv -> CmmGraph -> (CAFEnv, SlotEnv)
436 extendEnvsForSafeForeignCalls cafEnv slotEnv g =
437 fold_blocks block (cafEnv, slotEnv) g
439 tail ( bt_last_in cafTransfers (lookupFn cafEnv) l
440 , bt_last_in liveSlotTransfers (lookupFn slotEnv) l)
442 where (head, last) = goto_end (G.unzip b)
443 l = case last of LastOther l -> l
444 LastExit -> panic "extendEnvs lastExit"
445 tail _ z (ZFirst _ _) = z
446 tail lives@(cafs, slots) (cafEnv, slotEnv)
447 (ZHead h m@(MidForeignCall (Safe bid _) _ _ _)) =
448 let slots' = removeLiveSlotDefs slots m
449 slotEnv' = extendBlockEnv slotEnv bid slots'
450 cafEnv' = extendBlockEnv cafEnv bid cafs
451 in tail (upd lives m) (cafEnv', slotEnv') h
452 tail lives z (ZHead h m) = tail (upd lives m) z h
453 lookupFn map k = expectJust "extendEnvsForSafeFCalls" $ lookupBlockEnv map k
454 upd (cafs, slots) m =
455 (bt_middle_in cafTransfers cafs m, bt_middle_in liveSlotTransfers slots m)
457 -- Safe foreign calls: We need to insert the code that suspends and resumes
458 -- the thread before and after a safe foreign call.
459 -- Why do we do this so late in the pipeline?
460 -- Because we need this code to appear without interrruption: you can't rely on the
461 -- value of the stack pointer between the call and resetting the thread state;
462 -- you need to have an infotable on the young end of the stack both when
463 -- suspending the thread and making the foreign call.
464 -- All of this is much easier if we insert the suspend and resume calls here.
466 -- At the same time, we prepare for the stages of the compiler that
467 -- build the proc points. We have to do this at the same time because
468 -- the safe foreign calls need special treatment with respect to infotables.
469 -- A safe foreign call needs an infotable even though it isn't
470 -- a procpoint. The following datatype captures the information
471 -- needed to generate the infotables along with the Cmm data and procedures.
473 data CmmTopForInfoTables
474 = NoInfoTable CmmTopZ -- must be CmmData
475 | ProcInfoTable CmmTopZ BlockSet -- CmmProc; argument is its set of procpoints
476 | FloatingInfoTable CmmInfo BlockId UpdFrameOffset
477 instance Outputable CmmTopForInfoTables where
478 ppr (NoInfoTable t) = text "NoInfoTable: " <+> ppr t
479 ppr (ProcInfoTable t bids) = text "ProcInfoTable: " <+> ppr t <+> ppr bids
480 ppr (FloatingInfoTable info bid upd) =
481 text "FloatingInfoTable: " <+> ppr info <+> ppr bid <+> ppr upd
483 -- The `safeState' record collects the info we update while lowering the
484 -- safe foreign calls in the graph.
485 data SafeState = State { s_blocks :: BlockEnv CmmBlock
486 , s_pps :: ProcPointSet
487 , s_safeCalls :: [CmmTopForInfoTables]}
489 lowerSafeForeignCalls
490 :: [[CmmTopForInfoTables]] -> CmmTopZ -> FuelMonad [[CmmTopForInfoTables]]
491 lowerSafeForeignCalls rst t@(CmmData _ _) = return $ [NoInfoTable t] : rst
492 lowerSafeForeignCalls rst (CmmProc info l args g@(LGraph entry off _)) = do
493 let init = return $ State emptyBlockEnv emptyBlockSet []
494 let block b@(Block bid _ _) z = do
495 state@(State {s_pps = ppset, s_blocks = blocks}) <- z
496 let ppset' = if bid == entry then extendBlockSet ppset bid else ppset
497 state' = state { s_pps = ppset' }
498 if hasSafeForeignCall b
499 then lowerSafeCallBlock state' b
500 else return (state' { s_blocks = insertBlock b blocks })
501 State blocks' g_procpoints safeCalls <- fold_blocks block init g
503 : [ProcInfoTable (CmmProc info l args (LGraph entry off blocks')) g_procpoints]
506 -- Check for foreign calls -- if none, then we can avoid copying the block.
507 hasSafeForeignCall :: CmmBlock -> Bool
508 hasSafeForeignCall (Block _ _ t) = tail t
509 where tail (ZTail (MidForeignCall (Safe _ _) _ _ _) _) = True
510 tail (ZTail _ t) = tail t
511 tail (ZLast _) = False
513 -- Lower each safe call in the block, update the CAF and slot environments
514 -- to include each of those calls, and insert the new block in the blockEnv.
515 lowerSafeCallBlock :: SafeState-> CmmBlock -> FuelMonad SafeState
516 lowerSafeCallBlock state b = tail (return state) (ZBlock head (ZLast last))
517 where (head, last) = goto_end (G.unzip b)
518 tail s b@(ZBlock (ZFirst _ _) _) =
520 return $ state { s_blocks = insertBlock (G.zip b) (s_blocks state) }
521 tail s (ZBlock (ZHead h m@(MidForeignCall (Safe bid updfr_off) _ _ _)) t) =
524 { s_safeCalls = FloatingInfoTable emptyContInfoTable bid updfr_off :
526 (state'', t') <- lowerSafeForeignCall state' m t
527 tail (return state'') (ZBlock h t')
528 tail s (ZBlock (ZHead h m) t) = tail s (ZBlock h (ZTail m t))
531 -- Late in the code generator, we want to insert the code necessary
532 -- to lower a safe foreign call to a sequence of unsafe calls.
533 lowerSafeForeignCall ::
534 SafeState -> Middle -> ZTail Middle Last -> FuelMonad (SafeState, ZTail Middle Last)
535 lowerSafeForeignCall state m@(MidForeignCall (Safe infotable _) _ _ _) tail = do
536 let newTemp rep = getUniqueM >>= \u -> return (LocalReg u rep)
537 -- Both 'id' and 'new_base' are KindNonPtr because they're
538 -- RTS-only objects and are not subject to garbage collection
540 new_base <- newTemp (cmmRegType (CmmGlobal BaseReg))
541 let (caller_save, caller_load) = callerSaveVolatileRegs
542 load_tso <- newTemp gcWord -- TODO FIXME NOW
543 let suspendThread = CmmLit (CmmLabel (mkRtsCodeLabel (sLit "suspendThread")))
544 resumeThread = CmmLit (CmmLabel (mkRtsCodeLabel (sLit "resumeThread")))
545 suspend = mkStore (CmmReg spReg) (CmmLit (CmmBlock infotable)) <*>
548 mkUnsafeCall (ForeignTarget suspendThread
549 (ForeignConvention CCallConv [AddrHint] [AddrHint]))
550 [id] [CmmReg (CmmGlobal BaseReg)]
551 resume = mkUnsafeCall (ForeignTarget resumeThread
552 (ForeignConvention CCallConv [AddrHint] [AddrHint]))
553 [new_base] [CmmReg (CmmLocal id)] <*>
554 -- Assign the result to BaseReg: we
555 -- might now have a different Capability!
556 mkAssign (CmmGlobal BaseReg) (CmmReg (CmmLocal new_base)) <*>
558 loadThreadState load_tso
559 Graph tail' blocks' <-
560 liftUniq (graphOfAGraph (suspend <*> mkMiddle m <*> resume <*> mkZTail tail))
561 return (state {s_blocks = s_blocks state `plusBlockEnv` blocks'}, tail')
562 lowerSafeForeignCall _ _ _ = panic "lowerSafeForeignCall was passed something else"