+{-# OPTIONS_GHC -XNoMonoLocalBinds #-}
+-- Norman likes local bindings
+-- If this module lives on I'd like to get rid of this flag in due course
+
module CmmCPS (
-- | Converts C-- with full proceedures and parameters
-- to a CPS transformed C-- with the stack made manifest.
- cmmCPS
+ -- Well, sort of.
+ protoCmmCPS
) where
-#include "HsVersions.h"
-
+import CLabel
import Cmm
-import CmmLint
-import PprCmm
-
-import Dataflow
-import CmmLive
-import CmmBrokenBlock
+import CmmDecl
+import CmmBuildInfoTables
+import CmmCommonBlockElim
import CmmProcPoint
-import CmmCallConv
-
-import MachOp
-import ForeignCall
-import CLabel
-import SMRep
-import Constants
+import CmmSpillReload
+import CmmStackLayout
+import OptimizationFuel
import DynFlags
import ErrUtils
-import Maybes
+import HscTypes
+import Data.Maybe
+import Control.Monad
+import Data.Map (Map)
+import qualified Data.Map as Map
import Outputable
-import UniqSupply
-import UniqFM
-import UniqSet
-import Unique
-
-import Monad
-import IO
-import Data.List
+import StaticFlags
-----------------------------------------------------------------------------
-- |Top level driver for the CPS pass
-----------------------------------------------------------------------------
-cmmCPS :: DynFlags -- ^ Dynamic flags: -dcmm-lint -ddump-cps-cmm
- -> [Cmm] -- ^ Input C-- with Proceedures
- -> IO [Cmm] -- ^ Output CPS transformed C--
-cmmCPS dflags abstractC = do
- when (dopt Opt_DoCmmLinting dflags) $
- do showPass dflags "CmmLint"
- case firstJust $ map cmmLint abstractC of
- Just err -> do printDump err
- ghcExit dflags 1
- Nothing -> return ()
- showPass dflags "CPS"
-
- -- TODO: more lint checking
- -- check for use of branches to non-existant blocks
- -- check for use of Sp, SpLim, R1, R2, etc.
-
- uniqSupply <- mkSplitUniqSupply 'p'
- let supplies = listSplitUniqSupply uniqSupply
- let doCpsProc s (Cmm c) =
- Cmm $ concat $ zipWith cpsProc (listSplitUniqSupply s) c
- let continuationC = zipWith doCpsProc supplies abstractC
-
- dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC)
-
- -- TODO: add option to dump Cmm to file
-
- return continuationC
-
------------------------------------------------------------------------------
--- |CPS a single CmmTop (proceedure)
--- Only 'CmmProc' are transformed 'CmmData' will be left alone.
------------------------------------------------------------------------------
-
-cpsProc :: UniqSupply
- -> CmmTop -- ^Input proceedure
- -> [CmmTop] -- ^Output proceedure and continuations
-cpsProc uniqSupply x@(CmmData _ _) = [x]
-cpsProc uniqSupply x@(CmmProc info_table ident params blocks) = cps_procs
- where
- uniqes :: [[Unique]]
- uniqes = map uniqsFromSupply $ listSplitUniqSupply uniqSupply
-
- -- Break the block at each function call.
- -- The part after the function call will have to become a continuation.
- broken_blocks :: [BrokenBlock]
- broken_blocks =
- concat $ zipWith3 breakBlock uniqes blocks
- (FunctionEntry ident params:repeat ControlEntry)
-
- -- Calculate live variables for each broken block.
- --
- -- Nothing can be live on entry to the first block
- -- so we could take the tail, but for now we wont
- -- to help future proof the code.
- live :: BlockEntryLiveness
- live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks
-
- -- Calculate which blocks must be made into full fledged procedures.
- proc_points :: UniqSet BlockId
- proc_points = calculateProcPoints broken_blocks
-
- -- Construct a map so we can lookup a broken block by its 'BlockId'.
- block_env :: BlockEnv BrokenBlock
- block_env = blocksToBlockEnv broken_blocks
-
- -- Group the blocks into continuations based on the set of proc-points.
- continuations :: [Continuation]
- continuations = map (gatherBlocksIntoContinuation proc_points block_env)
- (uniqSetToList proc_points)
-
- -- Select the stack format on entry to each continuation.
- --
- -- This is an association list instead of a UniqFM because
- -- CLabel's don't have a 'Uniqueable' instance.
- formats :: [(CLabel, StackFormat)]
- formats = selectStackFormat live continuations
-
- -- Do the actual CPS transform.
- cps_procs :: [CmmTop]
- cps_procs = map (continuationToProc formats) continuations
-
---------------------------------------------------------------------------------
-
--- The format for the call to a continuation
--- The fst is the arguments that must be passed to the continuation
--- by the continuation's caller.
--- The snd is the live values that must be saved on stack.
--- A Nothing indicates an ignored slot.
--- The head of each list is the stack top or the first parameter.
-
--- The format for live values for a particular continuation
--- All on stack for now.
--- Head element is the top of the stack (or just under the header).
--- Nothing means an empty slot.
--- Future possibilities include callee save registers (i.e. passing slots in register)
--- and heap memory (not sure if that's usefull at all though, but it may
--- be worth exploring the design space).
-
-continuationLabel (Continuation _ _ l _ _) = l
-data Continuation =
- Continuation
- Bool -- True => Function entry, False => Continuation/return point
- [CmmStatic] -- Info table, may be empty
- CLabel -- Used to generate both info & entry labels
- CmmFormals -- Argument locals live on entry (C-- procedure params)
- [BrokenBlock] -- Code, may be empty. The first block is
- -- the entry point. The order is otherwise initially
- -- unimportant, but at some point the code gen will
- -- fix the order.
-
- -- the BlockId of the first block does not give rise
- -- to a label. To jump to the first block in a Proc,
- -- use the appropriate CLabel.
-
--- Describes the layout of a stack frame for a continuation
-data StackFormat
- = StackFormat {
- stack_label :: Maybe CLabel, -- The label occupying the top slot
- stack_frame_size :: WordOff, -- Total frame size in words (not including arguments)
- stack_live :: [(LocalReg, WordOff)] -- local reg offsets from stack top
- -- TODO: see if the above can be LocalReg
- }
-
--- A block can be a continuation of a call
--- A block can be a continuation of another block (w/ or w/o joins)
--- A block can be an entry to a function
-
------------------------------------------------------------------------------
-
-collectNonProcPointTargets ::
- UniqSet BlockId -> BlockEnv BrokenBlock
- -> UniqSet BlockId -> BlockId -> UniqSet BlockId
-collectNonProcPointTargets proc_points blocks current_targets block =
- if sizeUniqSet current_targets == sizeUniqSet new_targets
- then current_targets
- else foldl (collectNonProcPointTargets proc_points blocks) new_targets targets
- where
- block' = lookupWithDefaultUFM blocks (panic "TODO") block
- targets =
- -- Note the subtlety that since the extra branch after a call
- -- will always be to a block that is a proc-point,
- -- this subtraction will always remove that case
- uniqSetToList $ (mkUniqSet $ brokenBlockTargets block') `minusUniqSet` proc_points
- -- TODO: remove redundant uniqSetToList
- new_targets = current_targets `unionUniqSets` (mkUniqSet targets)
-
--- TODO: insert proc point code here
--- * Branches and switches to proc points may cause new blocks to be created
--- (or proc points could leave behind phantom blocks that just jump to them)
--- * Proc points might get some live variables passed as arguments
-
-gatherBlocksIntoContinuation ::
- UniqSet BlockId -> BlockEnv BrokenBlock
- -> BlockId -> Continuation
-gatherBlocksIntoContinuation proc_points blocks start =
- Continuation is_entry info_table clabel params body
- where
- children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) start) `delOneFromUniqSet` start
- start_block = lookupWithDefaultUFM blocks (panic "TODO") start
- children_blocks = map (lookupWithDefaultUFM blocks (panic "TODO")) (uniqSetToList children)
- body = start_block : children_blocks
- info_table = [] -- TODO
- start_block_entry = brokenBlockEntry start_block
- is_entry = case start_block_entry of
- FunctionEntry _ _ -> True
- _ -> False
- clabel = case start_block_entry of
- FunctionEntry label _ -> label
- _ -> mkReturnPtLabel $ getUnique start
- params = case start_block_entry of
- FunctionEntry _ args -> args
- ContinuationEntry args -> args
- ControlEntry -> [] -- TODO: it's a proc-point, we could pass lives in parameter registers
-
---------------------------------------------------------------------------------
--- For now just select the continuation orders in the order they are in the set with no gaps
-
-selectStackFormat :: BlockEnv CmmLive -> [Continuation] -> [(CLabel, StackFormat)]
-selectStackFormat live continuations =
- map (\c -> (continuationLabel c, selectStackFormat' c)) continuations
- where
- selectStackFormat' (Continuation True info_table label formals blocks) =
- StackFormat (Just label) 0 []
- selectStackFormat' (Continuation False info_table label formals blocks) =
- -- TODO: assumes the first block is the entry block
- let ident = brokenBlockId $ head blocks -- TODO: CLabel isn't a uniquable, but we need a better way than this
- in live_to_format label formals $ lookupWithDefaultUFM live unknown_block ident
-
- live_to_format :: CLabel -> CmmFormals -> CmmLive -> StackFormat
- live_to_format label formals live =
- foldl extend_format
- (StackFormat (Just label) retAddrSizeW [])
- (uniqSetToList (live `minusUniqSet` mkUniqSet formals))
-
- extend_format :: StackFormat -> LocalReg -> StackFormat
- extend_format (StackFormat label size offsets) reg =
- StackFormat label (slot_size reg + size) ((reg, size) : offsets)
-
- slot_size :: LocalReg -> Int
- slot_size reg = ((machRepByteWidth (localRegRep reg) - 1) `div` wORD_SIZE) + 1
-
- unknown_block = panic "unknown BlockId in selectStackFormat"
-
-continuationToProc :: [(CLabel, StackFormat)] -> Continuation -> CmmTop
-continuationToProc formats (Continuation is_entry info label formals blocks) =
- CmmProc info label formals (map (continuationToProc' label formats) blocks)
- where
- continuationToProc' :: CLabel -> [(CLabel, StackFormat)] -> BrokenBlock
- -> CmmBasicBlock
- continuationToProc' curr_ident formats (BrokenBlock ident entry stmts _ exit) =
- BasicBlock ident (prefix++stmts++postfix)
- where
- curr_format = maybe unknown_block id $ lookup curr_ident formats
- unknown_block = panic "unknown BlockId in continuationToProc"
- prefix = case entry of
- ControlEntry -> []
- FunctionEntry _ formals -> -- TODO: gc_stack_check
- function_entry formals curr_format
- ContinuationEntry formals ->
- function_entry formals curr_format
- postfix = case exit of
- FinalBranch next -> [CmmBranch next]
- FinalSwitch expr targets -> [CmmSwitch expr targets]
- FinalReturn arguments ->
- tail_call (stack_frame_size curr_format)
- (CmmLoad (CmmReg spReg) wordRep)
- arguments
- FinalJump target arguments ->
- tail_call (stack_frame_size curr_format) target arguments
- FinalCall next (CmmForeignCall target CmmCallConv)
- results arguments ->
- pack_continuation curr_format cont_format ++
- tail_call (stack_frame_size curr_format - stack_frame_size cont_format)
- target arguments
- where
- cont_format = maybe unknown_block id $
- lookup (mkReturnPtLabel $ getUnique next) formats
- FinalCall next _ results arguments -> panic "unimplemented CmmCall"
-
---------------------------------------------------------------------------------
--- Functions that generate CmmStmt sequences
--- for packing/unpacking continuations
--- and entering/exiting functions
-
-tail_call :: WordOff -> CmmExpr -> CmmActuals -> [CmmStmt]
-tail_call spRel target arguments
- = store_arguments ++ adjust_spReg ++ jump where
- store_arguments =
- [stack_put spRel expr offset
- | ((expr, _), StackParam offset) <- argument_formats] ++
- [global_put expr global
- | ((expr, _), RegisterParam global) <- argument_formats]
- adjust_spReg =
- if spRel == 0
- then []
- else [CmmAssign spReg (CmmRegOff spReg (spRel*wORD_SIZE))]
- jump = [CmmJump target arguments]
-
- argument_formats = assignArguments (cmmExprRep . fst) arguments
-
-gc_stack_check :: WordOff -> [CmmStmt]
-gc_stack_check max_frame_size
- = check_stack_limit where
- check_stack_limit = [
- CmmCondBranch
- (CmmMachOp (MO_U_Lt $ cmmRegRep spReg)
- [CmmRegOff spReg max_frame_size, CmmReg spLimReg])
- gc_block]
- gc_block = panic "gc_check not implemented" -- TODO: get stack and heap checks to go to same
-
--- TODO: fix branches to proc point (we have to insert a new block to marshel the continuation)
-pack_continuation :: StackFormat -> StackFormat -> [CmmStmt]
-pack_continuation (StackFormat curr_id curr_frame_size _)
- (StackFormat cont_id cont_frame_size cont_offsets)
- = store_live_values ++ set_stack_header where
- -- TODO: only save variables when actually needed (may be handled by latter pass)
- store_live_values =
- [stack_put spRel (CmmReg (CmmLocal reg)) offset
- | (reg, offset) <- cont_offsets]
- set_stack_header =
- if not needs_header
- then []
- else [stack_put spRel continuation_function 0]
-
- spRel = curr_frame_size - cont_frame_size
- continuation_function = CmmLit $ CmmLabel $ fromJust cont_id
- needs_header =
- case (curr_id, cont_id) of
- (Just x, Just y) -> x /= y
- _ -> isJust cont_id
-
--- Lazy adjustment of stack headers assumes all blocks
--- that could branch to eachother (i.e. control blocks)
--- have the same stack format (this causes a problem
--- only for proc-point).
-function_entry :: CmmFormals -> StackFormat -> [CmmStmt]
-function_entry formals (StackFormat _ _ curr_offsets)
- = load_live_values ++ load_args where
- -- TODO: only save variables when actually needed (may be handled by latter pass)
- load_live_values =
- [stack_get 0 reg offset
- | (reg, offset) <- curr_offsets]
- load_args =
- [stack_get 0 reg offset
- | (reg, StackParam offset) <- argument_formats] ++
- [global_get reg global
- | (reg, RegisterParam global) <- argument_formats]
-
- argument_formats = assignArguments (localRegRep) formals
-
------------------------------------------------------------------------------
--- Section: Stack and argument register puts and gets
------------------------------------------------------------------------------
--- TODO: document
-
--- |Construct a 'CmmStmt' that will save a value on the stack
-stack_put :: WordOff -- ^ Offset from the real 'Sp' that 'offset'
- -- is relative to (added to offset)
- -> CmmExpr -- ^ What to store onto the stack
- -> WordOff -- ^ Where on the stack to store it
- -- (positive <=> higher addresses)
- -> CmmStmt
-stack_put spRel expr offset =
- CmmStore (CmmRegOff spReg (wORD_SIZE*(spRel + offset))) expr
-
---------------------------------
--- |Construct a
-stack_get :: WordOff
- -> LocalReg
- -> WordOff
- -> CmmStmt
-stack_get spRel reg offset =
- CmmAssign (CmmLocal reg) (CmmLoad (CmmRegOff spReg (wORD_SIZE*(spRel + offset))) (localRegRep reg))
-global_put :: CmmExpr -> GlobalReg -> CmmStmt
-global_put expr global = CmmAssign (CmmGlobal global) expr
-global_get :: LocalReg -> GlobalReg -> CmmStmt
-global_get reg global = CmmAssign (CmmLocal reg) (CmmReg (CmmGlobal global))
-
+-- There are two complications here:
+-- 1. We need to compile the procedures in two stages because we need
+-- an analysis of the procedures to tell us what CAFs they use.
+-- The first stage returns a map from procedure labels to CAFs,
+-- along with a closure that will compute SRTs and attach them to
+-- the compiled procedures.
+-- The second stage is to combine the CAF information into a top-level
+-- CAF environment mapping non-static closures to the CAFs they keep live,
+-- then pass that environment to the closures returned in the first
+-- stage of compilation.
+-- 2. We need to thread the module's SRT around when the SRT tables
+-- are computed for each procedure.
+-- The SRT needs to be threaded because it is grown lazily.
+protoCmmCPS :: HscEnv -- Compilation env including
+ -- dynamic flags: -dcmm-lint -ddump-cps-cmm
+ -> (TopSRT, [Cmm]) -- SRT table and accumulating list of compiled procs
+ -> Cmm -- Input C-- with Procedures
+ -> IO (TopSRT, [Cmm]) -- Output CPS transformed C--
+protoCmmCPS hsc_env (topSRT, rst) (Cmm tops) =
+ do let dflags = hsc_dflags hsc_env
+ showPass dflags "CPSZ"
+ (cafEnvs, tops) <- liftM unzip $ mapM (cpsTop hsc_env) tops
+ let topCAFEnv = mkTopCAFInfo (concat cafEnvs)
+ (topSRT, tops) <- foldM (toTops hsc_env topCAFEnv) (topSRT, []) tops
+ let cmms = Cmm (reverse (concat tops))
+ dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "Post CPS Cmm" (ppr cmms)
+ return (topSRT, cmms : rst)
+
+{- [Note global fuel]
+~~~~~~~~~~~~~~~~~~~~~
+The identity and the last pass are stored in
+mutable reference cells in an 'HscEnv' and are
+global to one compiler session.
+-}
+
+-- EZY: It might be helpful to have an easy way of dumping the "pre"
+-- input for any given phase, besides just turning it all on with
+-- -ddump-cmmz
+
+cpsTop :: HscEnv -> CmmTop -> IO ([(CLabel, CAFSet)], [(CAFSet, CmmTop)])
+cpsTop _ p@(CmmData {}) = return ([], [(Map.empty, p)])
+cpsTop hsc_env (CmmProc h@(TopInfo {stack_info=StackInfo {arg_space=entry_off}}) l g) =
+ do
+ -- Why bother doing these early: dualLivenessWithInsertion,
+ -- insertLateReloads, rewriteAssignments?
+
+ ----------- Eliminate common blocks -------------------
+ g <- return $ elimCommonBlocks g
+ dump Opt_D_dump_cmmz_cbe "Post common block elimination" g
+ -- Any work storing block Labels must be performed _after_ elimCommonBlocks
+
+ ----------- Proc points -------------------
+ let callPPs = callProcPoints g
+ procPoints <- run $ minimalProcPointSet callPPs g
+ g <- run $ addProcPointProtocols callPPs procPoints g
+ dump Opt_D_dump_cmmz_proc "Post Proc Points Added" g
+
+ ----------- Spills and reloads -------------------
+ g <- run $ dualLivenessWithInsertion procPoints g
+ dump Opt_D_dump_cmmz_spills "Post spills and reloads" g
+
+ ----------- Sink and inline assignments -------------------
+ g <- runOptimization $ rewriteAssignments g
+ dump Opt_D_dump_cmmz_rewrite "Post rewrite assignments" g
+
+ ----------- Eliminate dead assignments -------------------
+ -- Remove redundant reloads (and any other redundant asst)
+ g <- runOptimization $ removeDeadAssignmentsAndReloads procPoints g
+ dump Opt_D_dump_cmmz_dead "Post Dead Assignment Elimination" g
+
+ ----------- Zero dead stack slots (Debug only) ---------------
+ -- Debugging: stubbing slots on death can cause crashes early
+ g <- if opt_StubDeadValues
+ then run $ stubSlotsOnDeath g
+ else return g
+ dump Opt_D_dump_cmmz_stub "Post stub dead stack slots" g
+
+ --------------- Stack layout ----------------
+ slotEnv <- run $ liveSlotAnal g
+ let spEntryMap = getSpEntryMap entry_off g
+ mbpprTrace "live slot analysis results: " (ppr slotEnv) $ return ()
+ let areaMap = layout procPoints spEntryMap slotEnv entry_off g
+ mbpprTrace "areaMap" (ppr areaMap) $ return ()
+
+ ------------ Manifest the stack pointer --------
+ g <- run $ manifestSP spEntryMap areaMap entry_off g
+ dump Opt_D_dump_cmmz_sp "Post manifestSP" g
+ -- UGH... manifestSP can require updates to the procPointMap.
+ -- We can probably do something quicker here for the update...
+
+ ------------- Split into separate procedures ------------
+ procPointMap <- run $ procPointAnalysis procPoints g
+ dump Opt_D_dump_cmmz_procmap "procpoint map" procPointMap
+ gs <- run $ splitAtProcPoints l callPPs procPoints procPointMap
+ (CmmProc h l g)
+ mapM_ (dump Opt_D_dump_cmmz_split "Post splitting") gs
+
+ ------------- More CAFs and foreign calls ------------
+ cafEnv <- run $ cafAnal g
+ let localCAFs = catMaybes $ map (localCAFInfo cafEnv) gs
+ mbpprTrace "localCAFs" (ppr localCAFs) $ return ()
+
+ gs <- run $ mapM (lowerSafeForeignCalls areaMap) gs
+ mapM_ (dump Opt_D_dump_cmmz_lower "Post lowerSafeForeignCalls") gs
+
+ -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
+ gs <- return $ map (setInfoTableStackMap slotEnv areaMap) gs
+ mapM_ (dump Opt_D_dump_cmmz_info "after setInfoTableStackMap") gs
+ gs <- return $ map (bundleCAFs cafEnv) gs
+ mapM_ (dump Opt_D_dump_cmmz_cafs "after bundleCAFs") gs
+ return (localCAFs, gs)
+ where dflags = hsc_dflags hsc_env
+ mbpprTrace x y z = if dopt Opt_D_dump_cmmz dflags then pprTrace x y z else z
+ dump f txt g = do
+ -- ToDo: No easy way of say "dump all the cmmz, *and* split
+ -- them into files." Also, -ddump-cmmz doesn't play nicely
+ -- with -ddump-to-file, since the headers get omitted.
+ dumpIfSet_dyn dflags f txt (ppr g)
+ when (not (dopt f dflags)) $
+ dumpIfSet_dyn dflags Opt_D_dump_cmmz txt (ppr g)
+ -- Runs a required transformation/analysis
+ run = runInfiniteFuelIO (hsc_OptFuel hsc_env)
+ -- Runs an optional transformation/analysis (and should
+ -- thus be subject to optimization fuel)
+ runOptimization = runFuelIO (hsc_OptFuel hsc_env)
+
+-- This probably belongs in CmmBuildInfoTables?
+-- We're just finishing the job here: once we know what CAFs are defined
+-- in non-static closures, we can build the SRTs.
+toTops :: HscEnv -> Map CLabel CAFSet -> (TopSRT, [[CmmTop]])
+ -> [(CAFSet, CmmTop)] -> IO (TopSRT, [[CmmTop]])
+toTops hsc_env topCAFEnv (topSRT, tops) gs =
+ do let setSRT (topSRT, rst) g =
+ do (topSRT, gs) <- setInfoTableSRT topCAFEnv topSRT g
+ return (topSRT, gs : rst)
+ (topSRT, gs') <- runFuelIO (hsc_OptFuel hsc_env) $ foldM setSRT (topSRT, []) gs
+ return (topSRT, concat gs' : tops)
projects / ghc-hetmet.git / blobdiff