StgCmmMonad.hs 19.9 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
-----------------------------------------------------------------------------
--
-- Monad for Stg to C-- code generation
--
-- (c) The University of Glasgow 2004-2006
--
-----------------------------------------------------------------------------

module StgCmmMonad (
	FCode,	-- type

	initC, thenC, thenFC, listCs, listFCs, mapCs, mapFCs,
	returnFC, fixC, nopC, whenC, 
	newUnique, newUniqSupply, 

16
	emit, emitData, emitProc, emitProcWithConvention, emitSimpleProc,
17 18 19 20 21 22 23 24 25 26 27 28 29 30

	getCmm, cgStmtsToBlocks,
	getCodeR, getCode, getHeapUsage,

	forkClosureBody, forkStatics, forkAlts, forkProc, codeOnly,

	ConTagZ,

	Sequel(..),
	withSequel, getSequel,

	setSRTLabel, getSRTLabel, 
	setTickyCtrLabel, getTickyCtrLabel,

31 32
	withUpdFrameOff, getUpdFrameOff, initUpdFrameOff,

33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
	HeapUsage(..), VirtualHpOffset,	initHpUsage,
	getHpUsage,  setHpUsage, heapHWM,
	setVirtHp, getVirtHp, setRealHp,

	getModuleName,

	-- ideally we wouldn't export these, but some other modules access internal state
	getState, setState, getInfoDown, getDynFlags, getThisPackage,

	-- more localised access to monad state	
	CgIdInfo(..), CgLoc(..),
	getBinds, setBinds, getStaticBinds,

	-- out of general friendliness, we also export ...
	CgInfoDownwards(..), CgState(..)	-- non-abstract
    ) where

#include "HsVersions.h"

import StgCmmClosure
import DynFlags
import MkZipCfgCmm
55
import ZipCfgCmmRep (UpdFrameOffset)
56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162
import BlockId
import Cmm
import CLabel
import TyCon	( PrimRep )
import SMRep
import Module
import Id
import VarEnv
import OrdList
import Unique
import Util()
import UniqSupply
import FastString(sLit)
import Outputable

import Control.Monad
import Data.List
import Prelude hiding( sequence )
import qualified Prelude( sequence )

infixr 9 `thenC`	-- Right-associative!
infixr 9 `thenFC`


--------------------------------------------------------
--	The FCode monad and its types
--------------------------------------------------------

newtype FCode a = FCode (CgInfoDownwards -> CgState -> (a, CgState))

instance Monad FCode where
	(>>=) = thenFC
	return = returnFC

{-# INLINE thenC #-}
{-# INLINE thenFC #-}
{-# INLINE returnFC #-}

initC :: DynFlags -> Module -> FCode a -> IO a
initC dflags mod (FCode code)
  = do	{ uniqs <- mkSplitUniqSupply 'c'
	; case code (initCgInfoDown dflags mod) (initCgState uniqs) of
	      (res, _) -> return res
	}

returnFC :: a -> FCode a
returnFC val = FCode (\_info_down state -> (val, state))

thenC :: FCode () -> FCode a -> FCode a
thenC (FCode m) (FCode k) = 
  	FCode (\info_down state -> let (_,new_state) = m info_down state in 
  		k info_down new_state)

nopC :: FCode ()
nopC = return ()

whenC :: Bool -> FCode () -> FCode ()
whenC True  code  = code
whenC False _code = nopC

listCs :: [FCode ()] -> FCode ()
listCs [] = return ()
listCs (fc:fcs) = do
	fc
	listCs fcs
   	
mapCs :: (a -> FCode ()) -> [a] -> FCode ()
mapCs = mapM_

thenFC	:: FCode a -> (a -> FCode c) -> FCode c
thenFC (FCode m) k = FCode (
	\info_down state ->
		let 
			(m_result, new_state) = m info_down state
			(FCode kcode) = k m_result
		in 
			kcode info_down new_state
	)

listFCs :: [FCode a] -> FCode [a]
listFCs = Prelude.sequence

mapFCs :: (a -> FCode b) -> [a] -> FCode [b]
mapFCs = mapM

fixC :: (a -> FCode a) -> FCode a
fixC fcode = FCode (
	\info_down state -> 
		let
			FCode fc = fcode v
			result@(v,_) = fc info_down state
			--	    ^--------^
		in
			result
	)


--------------------------------------------------------
--	The code generator environment
--------------------------------------------------------

-- This monadery has some information that it only passes 
-- *downwards*, as well as some ``state'' which is modified 
-- as we go along.

data CgInfoDownwards	-- information only passed *downwards* by the monad
  = MkCgInfoDown {
163 164 165 166 167 168 169
	cgd_dflags     :: DynFlags,
	cgd_mod        :: Module,	  -- Module being compiled
	cgd_statics    :: CgBindings,	  -- [Id -> info] : static environment
	cgd_srt_lbl    :: CLabel,	  -- Label of the current top-level SRT
	cgd_updfr_off  :: UpdFrameOffset, -- Size of current update frame
	cgd_ticky      :: CLabel,	  -- Current destination for ticky counts
	cgd_sequel     :: Sequel	  -- What to do at end of basic block
170 171 172 173 174 175 176 177 178 179
  }

type CgBindings = IdEnv CgIdInfo

data CgIdInfo
  = CgIdInfo	
	{ cg_id :: Id	-- Id that this is the info for
			-- Can differ from the Id at occurrence sites by 
			-- virtue of being externalised, for splittable C
	, cg_lf  :: LambdaFormInfo 
180
	, cg_loc :: CgLoc		     -- CmmExpr for the *tagged* value
181 182
	, cg_rep :: PrimRep		     -- Cache for (idPrimRep id)
        , cg_tag :: {-# UNPACK #-} !DynTag   -- Cache for (lfDynTag cg_lf)
183
        }
184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211

data CgLoc
  = CmmLoc CmmExpr	-- A stable CmmExpr; that is, one not mentioning
			-- Hp, so that it remains valid across calls

  | LneLoc BlockId [LocalReg]  	   -- A join point
	-- A join point (= let-no-escape) should only 
	-- be tail-called, and in a saturated way.
	-- To tail-call it, assign to these locals, 
	-- and branch to the block id

instance Outputable CgIdInfo where
  ppr (CgIdInfo { cg_id = id, cg_loc = loc })
    = ppr id <+> ptext (sLit "-->") <+> ppr loc

instance Outputable CgLoc where
  ppr (CmmLoc e)    = ptext (sLit "cmm") <+> ppr e
  ppr (LneLoc b rs) = ptext (sLit "lne") <+> ppr b <+> ppr rs


-- Sequel tells what to do with the result of this expression
data Sequel
  = Return Bool		  -- Return result(s) to continuation found on the stack
			  -- 	True <=> the continuation is update code (???)

  | AssignTo 
	[LocalReg]	-- Put result(s) in these regs and fall through
			-- 	NB: no void arguments here
212 213 214 215
        Bool            -- Should we adjust the heap pointer back to recover
                        -- space that's unused on this path?
                        -- We need to do this only if the expression may
                        -- allocate (e.g. it's a foreign call or allocating primOp)
216 217 218
instance Show Sequel where
  show (Return _) = "Sequel: Return"
  show (AssignTo _ _) = "Sequel: Assign"
219 220 221

initCgInfoDown :: DynFlags -> Module -> CgInfoDownwards
initCgInfoDown dflags mod
222 223 224 225 226 227 228
  = MkCgInfoDown {	cgd_dflags    = dflags,
			cgd_mod       = mod,
			cgd_statics   = emptyVarEnv,
			cgd_srt_lbl   = error "initC: srt_lbl",
			cgd_updfr_off = initUpdFrameOff,
			cgd_ticky     = mkTopTickyCtrLabel,
			cgd_sequel    = initSequel }
229 230 231 232

initSequel :: Sequel
initSequel = Return False

233 234 235
initUpdFrameOff :: UpdFrameOffset
initUpdFrameOff = widthInBytes wordWidth -- space for the RA

236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254

--------------------------------------------------------
--	The code generator state
--------------------------------------------------------

data CgState
  = MkCgState {
     cgs_stmts :: CmmAGraph,	  -- Current procedure

     cgs_tops  :: OrdList CmmTopZ,
	-- Other procedures and data blocks in this compilation unit
	-- Both are ordered only so that we can 
	-- reduce forward references, when it's easy to do so
     
     cgs_binds :: CgBindings,	-- [Id -> info] : *local* bindings environment
     				-- Bindings for top-level things are given in
				-- the info-down part

     cgs_hp_usg  :: HeapUsage,
255

256 257 258 259 260 261 262 263 264 265 266 267
     cgs_uniqs :: UniqSupply }

data HeapUsage =
  HeapUsage {
	virtHp :: VirtualHpOffset,	-- Virtual offset of highest-allocated word
	realHp :: VirtualHpOffset	-- realHp: Virtual offset of real heap ptr
  }

type VirtualHpOffset = WordOff

initCgState :: UniqSupply -> CgState
initCgState uniqs
268 269 270 271
  = MkCgState { cgs_stmts      = mkNop, cgs_tops = nilOL,
		cgs_binds      = emptyVarEnv, 
		cgs_hp_usg     = initHpUsage,
		cgs_uniqs      = uniqs }
272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421

stateIncUsage :: CgState -> CgState -> CgState
-- stateIncUsage@ e1 e2 incorporates in e1 
-- the heap high water mark found in e2.
stateIncUsage s1 s2@(MkCgState { cgs_hp_usg = hp_usg })
     = s1 { cgs_hp_usg  = cgs_hp_usg  s1 `maxHpHw`  virtHp hp_usg }
       `addCodeBlocksFrom` s2
		
addCodeBlocksFrom :: CgState -> CgState -> CgState
-- Add code blocks from the latter to the former
-- (The cgs_stmts will often be empty, but not always; see codeOnly)
s1 `addCodeBlocksFrom` s2
  = s1 { cgs_stmts = cgs_stmts s1 <*> cgs_stmts s2,
	 cgs_tops  = cgs_tops  s1 `appOL` cgs_tops  s2 }


-- The heap high water mark is the larger of virtHp and hwHp.  The latter is
-- only records the high water marks of forked-off branches, so to find the
-- heap high water mark you have to take the max of virtHp and hwHp.  Remember,
-- virtHp never retreats!
-- 
-- Note Jan 04: ok, so why do we only look at the virtual Hp??

heapHWM :: HeapUsage -> VirtualHpOffset
heapHWM = virtHp

initHpUsage :: HeapUsage 
initHpUsage = HeapUsage { virtHp = 0, realHp = 0 }

maxHpHw :: HeapUsage -> VirtualHpOffset -> HeapUsage
hp_usg `maxHpHw` hw = hp_usg { virtHp = virtHp hp_usg `max` hw }


--------------------------------------------------------
-- Operators for getting and setting the state and "info_down".
--------------------------------------------------------

getState :: FCode CgState
getState = FCode $ \_info_down state -> (state,state)

setState :: CgState -> FCode ()
setState state = FCode $ \_info_down _ -> ((),state)

getHpUsage :: FCode HeapUsage
getHpUsage = do
	state <- getState
	return $ cgs_hp_usg state
	
setHpUsage :: HeapUsage -> FCode ()
setHpUsage new_hp_usg = do
	state <- getState
	setState $ state {cgs_hp_usg = new_hp_usg}

setVirtHp :: VirtualHpOffset -> FCode ()
setVirtHp new_virtHp
  = do	{ hp_usage <- getHpUsage
	; setHpUsage (hp_usage {virtHp = new_virtHp}) }

getVirtHp :: FCode VirtualHpOffset
getVirtHp 
  = do	{ hp_usage <- getHpUsage
	; return (virtHp hp_usage) }

setRealHp ::  VirtualHpOffset -> FCode ()
setRealHp new_realHp
  = do	{ hp_usage <- getHpUsage
	; setHpUsage (hp_usage {realHp = new_realHp}) }

getBinds :: FCode CgBindings
getBinds = do
	state <- getState
	return $ cgs_binds state
	
setBinds :: CgBindings -> FCode ()
setBinds new_binds = do
	state <- getState
	setState $ state {cgs_binds = new_binds}

getStaticBinds :: FCode CgBindings
getStaticBinds = do
	info  <- getInfoDown
	return (cgd_statics info)

withState :: FCode a -> CgState -> FCode (a,CgState)
withState (FCode fcode) newstate = FCode $ \info_down state -> 
	let (retval, state2) = fcode info_down newstate in ((retval,state2), state)

newUniqSupply :: FCode UniqSupply
newUniqSupply = do
	state <- getState
	let (us1, us2) = splitUniqSupply (cgs_uniqs state)
	setState $ state { cgs_uniqs = us1 }
	return us2

newUnique :: FCode Unique
newUnique = do
	us <- newUniqSupply
	return (uniqFromSupply us)

------------------
getInfoDown :: FCode CgInfoDownwards
getInfoDown = FCode $ \info_down state -> (info_down,state)

getDynFlags :: FCode DynFlags
getDynFlags = liftM cgd_dflags getInfoDown

getThisPackage :: FCode PackageId
getThisPackage = liftM thisPackage getDynFlags

withInfoDown :: FCode a -> CgInfoDownwards -> FCode a
withInfoDown (FCode fcode) info_down = FCode $ \_ state -> fcode info_down state 

doFCode :: FCode a -> CgInfoDownwards -> CgState -> (a,CgState)
doFCode (FCode fcode) info_down state = fcode info_down state


-- ----------------------------------------------------------------------------
-- Get the current module name

getModuleName :: FCode Module
getModuleName = do { info <- getInfoDown; return (cgd_mod info) }

-- ----------------------------------------------------------------------------
-- Get/set the end-of-block info

withSequel :: Sequel -> FCode () -> FCode ()
withSequel sequel code
  = do	{ info  <- getInfoDown
	; withInfoDown code (info {cgd_sequel = sequel }) }

getSequel :: FCode Sequel
getSequel = do  { info <- getInfoDown
		; return (cgd_sequel info) }

-- ----------------------------------------------------------------------------
-- Get/set the current SRT label

-- There is just one SRT for each top level binding; all the nested
-- bindings use sub-sections of this SRT.  The label is passed down to
-- the nested bindings via the monad.

getSRTLabel :: FCode CLabel	-- Used only by cgPanic
getSRTLabel = do info  <- getInfoDown
		 return (cgd_srt_lbl info)

setSRTLabel :: CLabel -> FCode a -> FCode a
setSRTLabel srt_lbl code
  = do  info <- getInfoDown
	withInfoDown code (info { cgd_srt_lbl = srt_lbl})

422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441
-- ----------------------------------------------------------------------------
-- Get/set the size of the update frame

-- We keep track of the size of the update frame so that we
-- can set the stack pointer to the proper address on return
-- (or tail call) from the closure.
-- There should be at most one update frame for each closure.
-- Note: I'm including the size of the original return address
-- in the size of the update frame -- hence the default case on `get'.

withUpdFrameOff :: UpdFrameOffset -> FCode () -> FCode ()
withUpdFrameOff size code
  = do	{ info  <- getInfoDown
	; withInfoDown code (info {cgd_updfr_off = size }) }

getUpdFrameOff :: FCode UpdFrameOffset
getUpdFrameOff
  = do	{ info  <- getInfoDown
	; return $ cgd_updfr_off info }

442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474
-- ----------------------------------------------------------------------------
-- Get/set the current ticky counter label

getTickyCtrLabel :: FCode CLabel
getTickyCtrLabel = do
	info <- getInfoDown
	return (cgd_ticky info)

setTickyCtrLabel :: CLabel -> FCode () -> FCode ()
setTickyCtrLabel ticky code = do
	info <- getInfoDown
	withInfoDown code (info {cgd_ticky = ticky})


--------------------------------------------------------
-- 		Forking
--------------------------------------------------------

forkClosureBody :: FCode () -> FCode ()
-- forkClosureBody takes a code, $c$, and compiles it in a 
-- fresh environment, except that:
--	- compilation info and statics are passed in unchanged.
--	- local bindings are passed in unchanged
--	  (it's up to the enclosed code to re-bind the
--	   free variables to a field of the closure)
-- 
-- The current state is passed on completely unaltered, except that
-- C-- from the fork is incorporated.

forkClosureBody body_code
  = do	{ info <- getInfoDown
	; us   <- newUniqSupply
	; state <- getState
475 476
   	; let	body_info_down = info { cgd_sequel    = initSequel
                                      , cgd_updfr_off = initUpdFrameOff }
477 478 479 480 481 482 483 484 485 486 487 488 489 490
		fork_state_in = (initCgState us) { cgs_binds = cgs_binds state }
		((),fork_state_out)
		    = doFCode body_code body_info_down fork_state_in
	; setState $ state `addCodeBlocksFrom` fork_state_out }
	
forkStatics :: FCode a -> FCode a
-- @forkStatics@ $fc$ compiles $fc$ in an environment whose *statics* come
-- from the current *local bindings*, but which is otherwise freshly initialised.
-- The Abstract~C returned is attached to the current state, but the
-- bindings and usage information is otherwise unchanged.
forkStatics body_code
  = do	{ info  <- getInfoDown
	; us    <- newUniqSupply
	; state <- getState
491 492 493
	; let	rhs_info_down = info { cgd_statics = cgs_binds state
				     , cgd_sequel  = initSequel 
			             , cgd_updfr_off = initUpdFrameOff }
494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509
		(result, fork_state_out) = doFCode body_code rhs_info_down 
						   (initCgState us)
	; setState (state `addCodeBlocksFrom` fork_state_out)
	; return result }

forkProc :: FCode a -> FCode a
-- 'forkProc' takes a code and compiles it in the *current* environment,
-- returning the graph thus constructed. 
--
-- The current environment is passed on completely unchanged to
-- the successor.  In particular, any heap usage from the enclosed
-- code is discarded; it should deal with its own heap consumption
forkProc body_code
  = do	{ info_down <- getInfoDown
	; us    <- newUniqSupply
	; state <- getState
510
   	; let	info_down' = info_down -- { cgd_sequel = initSequel }
511 512
                fork_state_in = (initCgState us) { cgs_binds = cgs_binds state }
		(result, fork_state_out) = doFCode body_code info_down' fork_state_in
513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598
  	; setState $ state `addCodeBlocksFrom` fork_state_out
	; return result }

codeOnly :: FCode () -> FCode ()
-- Emit any code from the inner thing into the outer thing
-- Do not affect anything else in the outer state
-- Used in almost-circular code to prevent false loop dependencies
codeOnly body_code
  = do	{ info_down <- getInfoDown
	; us   <- newUniqSupply
	; state <- getState
	; let	fork_state_in = (initCgState us) { cgs_binds   = cgs_binds state,
					           cgs_hp_usg  = cgs_hp_usg state }
		((), fork_state_out) = doFCode body_code info_down fork_state_in
	; setState $ state `addCodeBlocksFrom` fork_state_out }

forkAlts :: [FCode a] -> FCode [a]
-- (forkAlts' bs d) takes fcodes 'bs' for the branches of a 'case', and
-- an fcode for the default case 'd', and compiles each in the current
-- environment.  The current environment is passed on unmodified, except
-- that the virtual Hp is moved on to the worst virtual Hp for the branches

forkAlts branch_fcodes
  = do	{ info_down <- getInfoDown
	; us <- newUniqSupply
	; state <- getState
	; let compile us branch 
		= (us2, doFCode branch info_down branch_state)
		where
		  (us1,us2) = splitUniqSupply us
	          branch_state = (initCgState us1) {
					cgs_binds   = cgs_binds state,
					cgs_hp_usg  = cgs_hp_usg state }

	      (_us, results) = mapAccumL compile us branch_fcodes
	      (branch_results, branch_out_states) = unzip results
	; setState $ foldl stateIncUsage state branch_out_states
		-- NB foldl.  state is the *left* argument to stateIncUsage
	; return branch_results }

-- collect the code emitted by an FCode computation
getCodeR :: FCode a -> FCode (a, CmmAGraph)
getCodeR fcode
  = do	{ state1 <- getState
	; (a, state2) <- withState fcode (state1 { cgs_stmts = mkNop })
	; setState $ state2 { cgs_stmts = cgs_stmts state1  }
	; return (a, cgs_stmts state2) }

getCode :: FCode a -> FCode CmmAGraph
getCode fcode = do { (_,stmts) <- getCodeR fcode; return stmts }

-- 'getHeapUsage' applies a function to the amount of heap that it uses.
-- It initialises the heap usage to zeros, and passes on an unchanged
-- heap usage. 
--
-- It is usually a prelude to performing a GC check, so everything must
-- be in a tidy and consistent state.
-- 
-- Note the slightly subtle fixed point behaviour needed here

getHeapUsage :: (VirtualHpOffset -> FCode a) -> FCode a
getHeapUsage fcode
  = do	{ info_down <- getInfoDown
	; state <- getState
	; let	fstate_in = state { cgs_hp_usg  = initHpUsage }
		(r, fstate_out) = doFCode (fcode hp_hw) info_down fstate_in
		hp_hw = heapHWM (cgs_hp_usg fstate_out)	-- Loop here!
		
	; setState $ fstate_out { cgs_hp_usg = cgs_hp_usg state }
	; return r }

-- ----------------------------------------------------------------------------
-- Combinators for emitting code

emit :: CmmAGraph -> FCode ()
emit ag
  = do	{ state <- getState
	; setState $ state { cgs_stmts = cgs_stmts state <*> ag } }

emitData :: Section -> [CmmStatic] -> FCode ()
emitData sect lits
  = do 	{ state <- getState
	; setState $ state { cgs_tops = cgs_tops state `snocOL` data_block } }
  where
    data_block = CmmData sect lits

599 600 601
emitProcWithConvention :: Convention -> CmmInfo -> CLabel -> CmmFormals ->
                          CmmAGraph -> FCode ()
emitProcWithConvention conv info lbl args blocks
602
  = do  { us <- newUniqSupply
603
        ; let (offset, entry) = mkEntry (mkBlockId $ uniqFromSupply us) conv args
604 605
              blks = initUs_ us $ lgraphOfAGraph $ entry <*> blocks
        ; let proc_block = CmmProc info lbl args ((offset, Just initUpdFrameOff), blks)
606 607 608
        ; state <- getState
        ; setState $ state { cgs_tops = cgs_tops state `snocOL` proc_block } }

609
emitProc :: CmmInfo -> CLabel -> CmmFormals -> CmmAGraph -> FCode ()
610
emitProc = emitProcWithConvention NativeNodeCall
611

612
emitSimpleProc :: CLabel -> CmmAGraph -> FCode ()
613 614
emitSimpleProc lbl code = 
  emitProc (CmmInfo Nothing Nothing CmmNonInfoTable) lbl [] code
615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635

getCmm :: FCode () -> FCode CmmZ
-- Get all the CmmTops (there should be no stmts)
-- Return a single Cmm which may be split from other Cmms by
-- object splitting (at a later stage)
getCmm code 
  = do	{ state1 <- getState
	; ((), state2) <- withState code (state1 { cgs_tops  = nilOL })
	; setState $ state2 { cgs_tops = cgs_tops state1 } 
	; return (Cmm (fromOL (cgs_tops state2))) }

-- ----------------------------------------------------------------------------
-- CgStmts

-- These functions deal in terms of CgStmts, which is an abstract type
-- representing the code in the current proc.

-- turn CgStmts into [CmmBasicBlock], for making a new proc.
cgStmtsToBlocks :: CmmAGraph -> FCode CmmGraph
cgStmtsToBlocks stmts
  = do  { us <- newUniqSupply
636
	; return (initUs_ us (lgraphOfAGraph stmts)) }	
637