2 -- | Converts C-- with full proceedures and parameters
3 -- to a CPS transformed C-- with the stack made manifest.
7 #include "HsVersions.h"
41 -----------------------------------------------------------------------------
42 -- |Top level driver for the CPS pass
43 -----------------------------------------------------------------------------
44 cmmCPS :: DynFlags -- ^ Dynamic flags: -dcmm-lint -ddump-cps-cmm
45 -> [GenCmm CmmStatic CmmInfo CmmStmt] -- ^ Input C-- with Proceedures
46 -> IO [GenCmm CmmStatic [CmmStatic] CmmStmt] -- ^ Output CPS transformed C--
47 cmmCPS dflags abstractC = do
48 when (dopt Opt_DoCmmLinting dflags) $
49 do showPass dflags "CmmLint"
50 case firstJust $ map cmmLint abstractC of
51 Just err -> do printDump err
56 -- TODO: more lint checking
57 -- check for use of branches to non-existant blocks
58 -- check for use of Sp, SpLim, R1, R2, etc.
60 uniqSupply <- mkSplitUniqSupply 'p'
61 let supplies = listSplitUniqSupply uniqSupply
62 let doCpsProc s (Cmm c) =
63 Cmm $ concat $ zipWith cpsProc (listSplitUniqSupply s) c
64 let continuationC = zipWith doCpsProc supplies abstractC
66 dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC)
68 -- TODO: add option to dump Cmm to file
72 stg_gc_gen = mkRtsApFastLabel SLIT("gen_cg_TODO") --panic "Need the label for gc"
73 make_gc_block block_id fun_label formals safety = BasicBlock block_id stmts
75 stmts = [CmmCall stg_gc_gen_target [] [] safety,
76 CmmJump fun_expr actuals]
78 CmmForeignCall (CmmLit (CmmLabel stg_gc_gen)) CmmCallConv
79 actuals = map (\x -> (CmmReg (CmmLocal x), NoHint)) formals
80 fun_expr = CmmLit (CmmLabel fun_label)
82 make_gc_check stack_use gc_block =
84 (CmmMachOp (MO_U_Lt $ cmmRegRep spReg)
85 [CmmReg stack_use, CmmReg spLimReg])
88 force_gc_block old_info stack_use block_id fun_label formals =
90 CmmNonInfo (Just existing) -> (old_info, [], make_gc_check stack_use existing)
91 CmmInfo _ (Just existing) _ _ -> (old_info, [], make_gc_check stack_use existing)
93 -> (CmmNonInfo (Just block_id),
94 [make_gc_block block_id fun_label formals (CmmSafe NoC_SRT)],
95 make_gc_check stack_use block_id)
96 CmmInfo prof Nothing type_tag type_info
97 -> (CmmInfo prof (Just block_id) type_tag type_info,
98 [make_gc_block block_id fun_label formals (CmmSafe srt)],
99 make_gc_check stack_use block_id)
101 srt = case type_info of
102 ConstrInfo _ _ _ -> NoC_SRT
103 FunInfo _ srt' _ _ _ _ -> srt'
104 ThunkInfo _ srt' -> srt'
105 ThunkSelectorInfo _ srt' -> srt'
106 ContInfo _ srt' -> srt'
108 -----------------------------------------------------------------------------
109 -- |CPS a single CmmTop (proceedure)
110 -- Only 'CmmProc' are transformed 'CmmData' will be left alone.
111 -----------------------------------------------------------------------------
113 cpsProc :: UniqSupply
114 -> GenCmmTop CmmStatic CmmInfo CmmStmt -- ^Input proceedure
115 -> [GenCmmTop CmmStatic [CmmStatic] CmmStmt] -- ^Output proceedure and continuations
116 cpsProc uniqSupply (CmmData sec dat) = [CmmData sec dat]
117 cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs
119 (uniqSupply1, uniqSupply2) = splitUniqSupply uniqSupply
120 uniques :: [[Unique]]
121 uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply1
122 (gc_unique:stack_use_unique:info_uniques):adaptor_uniques:block_uniques = uniques
123 proc_uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply2
125 stack_use = CmmLocal (LocalReg stack_use_unique (cmmRegRep spReg) KindPtr)
128 forced_gc :: (CmmInfo, [CmmBasicBlock], [CmmStmt])
129 forced_gc = force_gc_block info stack_use (BlockId gc_unique) ident params
130 (forced_info, gc_blocks, check_stmts) = forced_gc
134 (BasicBlock id stmts) : bs ->
135 (BasicBlock id (check_stmts ++ stmts)) : (bs ++ gc_blocks)
136 [] -> [] -- If there is no code then we don't need a stack check
138 forced_gc_id = case forced_info of
139 CmmNonInfo (Just x) -> x
140 CmmInfo _ (Just x) _ _ -> x
142 -- Break the block at each function call.
143 -- The part after the function call will have to become a continuation.
144 broken_blocks :: ([(BlockId, ContFormat)], [BrokenBlock])
146 (\x -> (concatMap fst x, concatMap snd x)) $
147 zipWith3 (breakBlock [forced_gc_id])
150 (FunctionEntry forced_info ident params :
153 f' = selectContinuations (fst broken_blocks)
154 broken_blocks' = map (makeContinuationEntries f') $
156 zipWith (adaptBlockToFormat f')
160 -- Calculate live variables for each broken block.
162 -- Nothing can be live on entry to the first block
163 -- so we could take the tail, but for now we wont
164 -- to help future proof the code.
165 live :: BlockEntryLiveness
166 live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks'
168 -- Calculate which blocks must be made into full fledged procedures.
169 proc_points :: UniqSet BlockId
170 proc_points = calculateProcPoints broken_blocks'
172 -- Construct a map so we can lookup a broken block by its 'BlockId'.
173 block_env :: BlockEnv BrokenBlock
174 block_env = blocksToBlockEnv broken_blocks'
176 -- Group the blocks into continuations based on the set of proc-points.
177 continuations :: [Continuation (Either C_SRT CmmInfo)]
178 continuations = zipWith
179 (gatherBlocksIntoContinuation live proc_points block_env)
180 (uniqSetToList proc_points)
181 (Just forced_gc_id : repeat Nothing) {-dead-}
183 -- Select the stack format on entry to each continuation.
184 -- Return the max stack offset and an association list
186 -- This is an association list instead of a UniqFM because
187 -- CLabel's don't have a 'Uniqueable' instance.
188 formats :: [(CLabel, -- key
189 (CmmFormals, -- arguments
190 Maybe CLabel, -- label in top slot
191 [Maybe LocalReg]))] -- slots
192 formats = selectContinuationFormat live continuations
194 -- Do a little meta-processing on the stack formats such as
195 -- getting the individual frame sizes and the maximum frame size
196 formats' :: (WordOff, [(CLabel, ContinuationFormat)])
197 formats' = processFormats formats continuations
199 -- Update the info table data on the continuations with
200 -- the selected stack formats.
201 continuations' :: [Continuation CmmInfo]
202 continuations' = map (applyContinuationFormat (snd formats')) continuations
204 -- Do the actual CPS transform.
205 cps_procs :: [CmmTop]
206 cps_procs = zipWith (continuationToProc formats' stack_use) proc_uniques continuations'
208 -- Convert the info tables from CmmInfo to [CmmStatic]
209 -- We might want to put this in another pass eventually
210 info_procs :: [RawCmmTop]
211 info_procs = concat (zipWith mkInfoTable info_uniques cps_procs)
213 --------------------------------------------------------------------------------
215 -- The format for the call to a continuation
216 -- The fst is the arguments that must be passed to the continuation
217 -- by the continuation's caller.
218 -- The snd is the live values that must be saved on stack.
219 -- A Nothing indicates an ignored slot.
220 -- The head of each list is the stack top or the first parameter.
222 -- The format for live values for a particular continuation
223 -- All on stack for now.
224 -- Head element is the top of the stack (or just under the header).
225 -- Nothing means an empty slot.
226 -- Future possibilities include callee save registers (i.e. passing slots in register)
227 -- and heap memory (not sure if that's usefull at all though, but it may
228 -- be worth exploring the design space).
230 continuationLabel (Continuation _ l _ _ _) = l
231 data Continuation info =
233 info -- Left <=> Continuation created by the CPS
234 -- Right <=> Function or Proc point
235 CLabel -- Used to generate both info & entry labels
236 CmmFormals -- Argument locals live on entry (C-- procedure params)
237 Bool -- ^ True <=> GC block so ignore stack size
238 [BrokenBlock] -- Code, may be empty. The first block is
239 -- the entry point. The order is otherwise initially
240 -- unimportant, but at some point the code gen will
243 -- the BlockId of the first block does not give rise
244 -- to a label. To jump to the first block in a Proc,
245 -- use the appropriate CLabel.
247 data ContinuationFormat
248 = ContinuationFormat {
249 continuation_formals :: CmmFormals,
250 continuation_label :: Maybe CLabel, -- The label occupying the top slot
251 continuation_frame_size :: WordOff, -- Total frame size in words (not including arguments)
252 continuation_stack :: [Maybe LocalReg] -- local reg offsets from stack top
255 -- A block can be a continuation of a call
256 -- A block can be a continuation of another block (w/ or w/o joins)
257 -- A block can be an entry to a function
259 -----------------------------------------------------------------------------
261 collectNonProcPointTargets ::
262 UniqSet BlockId -> BlockEnv BrokenBlock
263 -> UniqSet BlockId -> [BlockId] -> UniqSet BlockId
264 collectNonProcPointTargets proc_points blocks current_targets new_blocks =
265 if sizeUniqSet current_targets == sizeUniqSet new_targets
268 (collectNonProcPointTargets proc_points blocks)
272 blocks' = map (lookupWithDefaultUFM blocks (panic "TODO")) new_blocks
274 -- Note the subtlety that since the extra branch after a call
275 -- will always be to a block that is a proc-point,
276 -- this subtraction will always remove that case
277 uniqSetToList $ (unionManyUniqSets $ map (mkUniqSet . brokenBlockTargets) blocks')
278 `minusUniqSet` proc_points
279 -- TODO: remove redundant uniqSetToList
280 new_targets = current_targets `unionUniqSets` (mkUniqSet targets)
282 -- TODO: insert proc point code here
283 -- * Branches and switches to proc points may cause new blocks to be created
284 -- (or proc points could leave behind phantom blocks that just jump to them)
285 -- * Proc points might get some live variables passed as arguments
287 gatherBlocksIntoContinuation ::
288 BlockEntryLiveness -> UniqSet BlockId -> BlockEnv BrokenBlock
289 -> BlockId -> Maybe BlockId -> Continuation (Either C_SRT CmmInfo)
290 gatherBlocksIntoContinuation live proc_points blocks start gc =
291 Continuation info_table clabel params is_gc_cont body
293 --start_and_gc = [start] -- : maybeToList gc
294 --children = (collectNonProcPointTargets proc_points blocks (mkUniqSet start_and_gc) start_and_gc) `minusUniqSet` (mkUniqSet start_and_gc)
295 children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) [start]) `minusUniqSet` (unitUniqSet start)
296 start_block = lookupWithDefaultUFM blocks (panic "TODO") start
297 unknown_block = panic "unknown block in gatherBlocksIntoContinuation"
298 --gc_block = map (lookupWithDefaultUFM blocks (panic "TODO)"))
300 children_blocks = map (lookupWithDefaultUFM blocks (panic "TODO")) (uniqSetToList children)
301 body = start_block : {-gc_block ++ -} children_blocks
303 -- We can't properly annotate the continuation's stack parameters
304 -- at this point because this is before stack selection
305 -- but we want to keep the C_SRT around so we use 'Either'.
306 info_table = case start_block_entry of
307 FunctionEntry info _ _ -> Right info
308 ContinuationEntry _ srt _ -> Left srt
309 ControlEntry -> Right (CmmNonInfo Nothing)
311 is_gc_cont = case start_block_entry of
312 FunctionEntry _ _ _ -> False
313 ContinuationEntry _ _ gc_cont -> gc_cont
314 ControlEntry -> False
316 start_block_entry = brokenBlockEntry start_block
317 clabel = case start_block_entry of
318 FunctionEntry _ label _ -> label
319 _ -> mkReturnPtLabel $ getUnique start
320 params = case start_block_entry of
321 FunctionEntry _ _ args -> args
322 ContinuationEntry args _ _ -> args
325 lookupWithDefaultUFM live unknown_block start
326 -- it's a proc-point, pass lives in parameter registers
328 --------------------------------------------------------------------------------
329 -- For now just select the continuation orders in the order they are in the set with no gaps
331 selectContinuationFormat :: BlockEnv CmmLive
332 -> [Continuation (Either C_SRT CmmInfo)]
333 -> [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))]
334 selectContinuationFormat live continuations =
335 map (\c -> (continuationLabel c, selectContinuationFormat' c)) continuations
337 selectContinuationFormat' (Continuation
338 (Right (CmmInfo _ _ _ (ContInfo format srt)))
340 (formals, Just label, format)
341 selectContinuationFormat' (Continuation (Right _) _ formals _ _) =
342 (formals, Nothing, [])
343 -- CPS generated continuations
344 selectContinuationFormat' (Continuation (Left srt) label formals _ blocks) =
345 -- TODO: assumes the first block is the entry block
346 let ident = brokenBlockId $ head blocks -- TODO: CLabel isn't a uniquable, but we need a better way than this
349 map Just $ uniqSetToList $
350 lookupWithDefaultUFM live unknown_block ident)
352 unknown_block = panic "unknown BlockId in selectContinuationFormat"
354 processFormats :: [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))]
355 -> [Continuation (Either C_SRT CmmInfo)]
356 -> (WordOff, [(CLabel, ContinuationFormat)])
357 processFormats formats continuations = (max_size, formats')
360 0 : map (continuationMaxStack formats') continuations
361 formats' = map make_format formats
362 make_format (label, (formals, top, stack)) =
365 continuation_formals = formals,
366 continuation_label = top,
367 continuation_frame_size = stack_size stack +
371 continuation_stack = stack })
373 -- TODO: get rid of "+ 1" etc.
374 label_size = 1 :: WordOff
377 stack_size (Nothing:formats) = 1 + stack_size formats -- one dead word
378 stack_size (Just reg:formats) = width + stack_size formats
380 width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
381 -- TODO: it would be better if we had a machRepWordWidth
383 continuationMaxStack :: [(CLabel, ContinuationFormat)]
386 continuationMaxStack _ (Continuation _ _ _ True _) = 0
387 continuationMaxStack formats (Continuation _ label _ False blocks) =
388 max_arg_size + continuation_frame_size stack_format
390 stack_format = maybe unknown_format id $ lookup label formats
391 unknown_format = panic "Unknown format in continuationMaxStack"
393 max_arg_size = maximum $ 0 : map block_max_arg_size blocks
395 block_max_arg_size block =
396 maximum (final_arg_size (brokenBlockExit block) :
397 map stmt_arg_size (brokenBlockStmts block))
399 final_arg_size (FinalReturn args) =
400 argumentsSize (cmmExprRep . fst) args
401 final_arg_size (FinalJump _ args) =
402 argumentsSize (cmmExprRep . fst) args
403 final_arg_size (FinalCall next _ _ args _ True) = 0
404 final_arg_size (FinalCall next _ _ args _ False) =
405 -- We have to account for the stack used when we build a frame
406 -- for the *next* continuation from *this* continuation
407 argumentsSize (cmmExprRep . fst) args +
408 continuation_frame_size next_format
410 next_format = maybe unknown_format id $ lookup next' formats
411 next' = mkReturnPtLabel $ getUnique next
415 stmt_arg_size (CmmJump _ args) =
416 argumentsSize (cmmExprRep . fst) args
417 stmt_arg_size (CmmCall _ _ _ (CmmSafe _)) =
418 panic "Safe call in processFormats"
419 stmt_arg_size (CmmReturn _) =
420 panic "CmmReturn in processFormats"
423 -----------------------------------------------------------------------------
424 applyContinuationFormat :: [(CLabel, ContinuationFormat)]
425 -> Continuation (Either C_SRT CmmInfo)
426 -> Continuation CmmInfo
428 -- User written continuations
429 applyContinuationFormat formats (Continuation
430 (Right (CmmInfo prof gc tag (ContInfo _ srt)))
431 label formals is_gc blocks) =
432 Continuation (CmmInfo prof gc tag (ContInfo format srt))
433 label formals is_gc blocks
435 format = continuation_stack $ maybe unknown_block id $ lookup label formats
436 unknown_block = panic "unknown BlockId in applyContinuationFormat"
438 -- User written non-continuation code
439 applyContinuationFormat formats (Continuation
440 (Right info) label formals is_gc blocks) =
441 Continuation info label formals is_gc blocks
443 -- CPS generated continuations
444 applyContinuationFormat formats (Continuation
445 (Left srt) label formals is_gc blocks) =
446 Continuation (CmmInfo prof gc tag (ContInfo (continuation_stack $ format) srt))
447 label formals is_gc blocks
449 gc = Nothing -- Generated continuations never need a stack check
450 -- TODO prof: this is the same as the current implementation
451 -- but I think it could be improved
452 prof = ProfilingInfo zeroCLit zeroCLit
453 tag = rET_SMALL -- cmmToRawCmm may convert it to rET_BIG
454 format = maybe unknown_block id $ lookup label formats
455 unknown_block = panic "unknown BlockId in applyContinuationFormat"
457 -----------------------------------------------------------------------------
458 continuationToProc :: (WordOff, [(CLabel, ContinuationFormat)])
461 -> Continuation CmmInfo
463 continuationToProc (max_stack, formats) stack_use uniques
464 (Continuation info label formals _ blocks) =
465 CmmProc info label formals (concat $ zipWith3 continuationToProc' uniques blocks (True : repeat False))
467 curr_format = maybe unknown_block id $ lookup label formats
468 unknown_block = panic "unknown BlockId in continuationToProc"
469 curr_stack = continuation_frame_size curr_format
470 arg_stack = argumentsSize localRegRep formals
472 param_stmts :: [CmmStmt]
473 param_stmts = function_entry curr_format
475 gc_stmts :: [CmmStmt]
478 CmmInfo _ (Just gc_block) _ _ ->
479 gc_stack_check' stack_use arg_stack (max_stack - curr_stack)
480 CmmInfo _ Nothing _ _ ->
481 panic "continuationToProc: missing GC block"
482 CmmNonInfo (Just gc_block) ->
483 gc_stack_check' stack_use arg_stack (max_stack - curr_stack)
484 CmmNonInfo Nothing ->
485 panic "continuationToProc: missing non-info GC block"
487 continuationToProc' :: Unique -> BrokenBlock -> Bool -> [CmmBasicBlock]
488 continuationToProc' unique (BrokenBlock ident entry stmts _ exit) is_entry =
489 case gc_prefix ++ param_prefix of
491 stmts -> [BasicBlock prefix_id (gc_prefix ++ param_prefix ++ [CmmBranch ident]),
494 main_block = BasicBlock ident (stmts ++ postfix)
495 prefix_id = BlockId unique
496 gc_prefix = case entry of
497 FunctionEntry _ _ _ -> gc_stmts
499 ContinuationEntry _ _ _ -> []
500 param_prefix = if is_entry
503 postfix = case exit of
505 if (mkReturnPtLabel $ getUnique next) == label
506 then [CmmBranch next]
507 else case lookup (mkReturnPtLabel $ getUnique next) formats of
508 Nothing -> [CmmBranch next]
510 pack_continuation False curr_format cont_format ++
511 tail_call (curr_stack - cont_stack)
512 (CmmLit $ CmmLabel $ mkReturnPtLabel $ getUnique next)
515 cont_stack = continuation_frame_size cont_format
516 arguments = map formal_to_actual (continuation_formals cont_format)
517 formal_to_actual reg = (CmmReg (CmmLocal reg), NoHint)
518 FinalSwitch expr targets -> [CmmSwitch expr targets]
519 FinalReturn arguments ->
521 (CmmLoad (CmmReg spReg) wordRep)
523 FinalJump target arguments ->
524 tail_call curr_stack target arguments
525 FinalCall next (CmmForeignCall target CmmCallConv)
526 results arguments _ _ ->
527 pack_continuation True curr_format cont_format ++
528 tail_call (curr_stack - cont_stack)
531 cont_format = maybe unknown_block id $
532 lookup (mkReturnPtLabel $ getUnique next) formats
533 cont_stack = continuation_frame_size cont_format
534 FinalCall next _ results arguments _ _ -> panic "unimplemented CmmCall"
536 -----------------------------------------------------------------------------
537 -- Functions that generate CmmStmt sequences
538 -- for packing/unpacking continuations
539 -- and entering/exiting functions
541 tail_call :: WordOff -> CmmExpr -> CmmActuals -> [CmmStmt]
542 tail_call spRel target arguments
543 = store_arguments ++ adjust_spReg ++ jump where
545 [stack_put spRel expr offset
546 | ((expr, _), StackParam offset) <- argument_formats] ++
547 [global_put expr global
548 | ((expr, _), RegisterParam global) <- argument_formats]
552 else [CmmAssign spReg (CmmRegOff spReg (spRel*wORD_SIZE))]
553 jump = [CmmJump target arguments]
555 argument_formats = assignArguments (cmmExprRep . fst) arguments
557 gc_stack_check' stack_use arg_stack max_frame_size =
558 if max_frame_size > arg_stack
559 then [CmmAssign stack_use (CmmRegOff spReg (-max_frame_size*wORD_SIZE))]
560 else [CmmAssign stack_use (CmmReg spLimReg)]
561 -- Trick the optimizer into eliminating the branch for us
563 gc_stack_check :: BlockId -> WordOff -> [CmmStmt]
564 gc_stack_check gc_block max_frame_size
565 = check_stack_limit where
566 check_stack_limit = [
568 (CmmMachOp (MO_U_Lt $ cmmRegRep spReg)
569 [CmmRegOff spReg (-max_frame_size*wORD_SIZE),
574 -- TODO: fix branches to proc point
575 -- (we have to insert a new block to marshel the continuation)
576 pack_continuation :: Bool -> ContinuationFormat -> ContinuationFormat -> [CmmStmt]
577 pack_continuation allow_header_set
578 (ContinuationFormat _ curr_id curr_frame_size _)
579 (ContinuationFormat _ cont_id cont_frame_size live_regs)
580 = store_live_values ++ set_stack_header where
581 -- TODO: only save variables when actually needed
582 -- (may be handled by latter pass)
584 [stack_put spRel (CmmReg (CmmLocal reg)) offset
585 | (reg, offset) <- cont_offsets]
587 if needs_header_set && allow_header_set
588 then [stack_put spRel continuation_function 0]
591 -- TODO: factor with function_entry and CmmInfo.hs(?)
592 cont_offsets = mkOffsets label_size live_regs
594 label_size = 1 :: WordOff
596 mkOffsets size [] = []
597 mkOffsets size (Nothing:regs) = mkOffsets (size+1) regs
598 mkOffsets size (Just reg:regs) = (reg, size):mkOffsets (size + width) regs
600 width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
601 -- TODO: it would be better if we had a machRepWordWidth
603 spRel = curr_frame_size - cont_frame_size
604 continuation_function = CmmLit $ CmmLabel $ fromJust cont_id
606 case (curr_id, cont_id) of
607 (Just x, Just y) -> x /= y
610 -- Lazy adjustment of stack headers assumes all blocks
611 -- that could branch to eachother (i.e. control blocks)
612 -- have the same stack format (this causes a problem
613 -- only for proc-point).
614 function_entry :: ContinuationFormat -> [CmmStmt]
615 function_entry (ContinuationFormat formals _ _ live_regs)
616 = load_live_values ++ load_args where
617 -- TODO: only save variables when actually needed
618 -- (may be handled by latter pass)
620 [stack_get 0 reg offset
621 | (reg, offset) <- curr_offsets]
623 [stack_get 0 reg offset
624 | (reg, StackParam offset) <- argument_formats] ++
625 [global_get reg global
626 | (reg, RegisterParam global) <- argument_formats]
628 argument_formats = assignArguments (localRegRep) formals
630 -- TODO: eliminate copy/paste with pack_continuation
631 curr_offsets = mkOffsets label_size live_regs
633 label_size = 1 :: WordOff
635 mkOffsets size [] = []
636 mkOffsets size (Nothing:regs) = mkOffsets (size+1) regs
637 mkOffsets size (Just reg:regs) = (reg, size):mkOffsets (size + width) regs
639 width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
640 -- TODO: it would be better if we had a machRepWordWidth
642 -----------------------------------------------------------------------------
643 -- Section: Stack and argument register puts and gets
644 -----------------------------------------------------------------------------
647 -- |Construct a 'CmmStmt' that will save a value on the stack
648 stack_put :: WordOff -- ^ Offset from the real 'Sp' that 'offset'
649 -- is relative to (added to offset)
650 -> CmmExpr -- ^ What to store onto the stack
651 -> WordOff -- ^ Where on the stack to store it
652 -- (positive <=> higher addresses)
654 stack_put spRel expr offset =
655 CmmStore (CmmRegOff spReg (wORD_SIZE*(spRel + offset))) expr
657 --------------------------------
663 stack_get spRel reg offset =
664 CmmAssign (CmmLocal reg)
665 (CmmLoad (CmmRegOff spReg (wORD_SIZE*(spRel + offset)))
667 global_put :: CmmExpr -> GlobalReg -> CmmStmt
668 global_put expr global = CmmAssign (CmmGlobal global) expr
669 global_get :: LocalReg -> GlobalReg -> CmmStmt
670 global_get reg global = CmmAssign (CmmLocal reg) (CmmReg (CmmGlobal global))