+++ /dev/null
------------------------------------------------------------------------------
---
--- Code generator utilities; mostly monadic
---
--- (c) The University of Glasgow 2004
---
------------------------------------------------------------------------------
-
-module CgUtils (
- addIdReps,
- cgLit,
- emitDataLits, emitRODataLits, emitIf, emitIfThenElse,
- emitRtsCall, emitRtsCallWithVols, emitRtsCallWithResult,
- assignTemp, newTemp,
- emitSimultaneously,
- emitSwitch, emitLitSwitch,
- tagToClosure,
-
- cmmAndWord, cmmOrWord, cmmNegate, cmmEqWord, cmmNeWord,
- cmmOffsetExprW, cmmOffsetExprB,
- cmmRegOffW, cmmRegOffB,
- cmmLabelOffW, cmmLabelOffB,
- cmmOffsetW, cmmOffsetB,
- cmmOffsetLitW, cmmOffsetLitB,
- cmmLoadIndexW,
-
- addToMem, addToMemE,
- mkWordCLit,
- mkStringCLit,
- packHalfWordsCLit,
- blankWord
- ) where
-
-#include "HsVersions.h"
-
-import CgMonad
-import TyCon ( TyCon, tyConName )
-import Id ( Id )
-import Constants ( wORD_SIZE )
-import SMRep ( CgRep, StgWord, hALF_WORD_SIZE_IN_BITS, ByteOff,
- WordOff, idCgRep )
-import PprCmm ( {- instances -} )
-import Cmm
-import CLabel
-import CmmUtils
-import MachOp ( MachRep(..), wordRep, MachOp(..), MachHint(..),
- mo_wordOr, mo_wordAnd, mo_wordNe, mo_wordEq,
- mo_wordULt, mo_wordUGt, mo_wordUGe, machRepByteWidth )
-import ForeignCall ( CCallConv(..) )
-import Literal ( Literal(..) )
-import CLabel ( CLabel, mkStringLitLabel )
-import Digraph ( SCC(..), stronglyConnComp )
-import ListSetOps ( assocDefault )
-import Util ( filterOut, sortLe )
-import DynFlags ( DynFlags(..), HscTarget(..) )
-import Packages ( HomeModules )
-import FastString ( LitString, FastString, bytesFS )
-import Outputable
-
-import Char ( ord )
-import DATA_BITS
-import DATA_WORD ( Word8 )
-import Maybe ( isNothing )
-
--------------------------------------------------------------------------
---
--- Random small functions
---
--------------------------------------------------------------------------
-
-addIdReps :: [Id] -> [(CgRep, Id)]
-addIdReps ids = [(idCgRep id, id) | id <- ids]
-
--------------------------------------------------------------------------
---
--- Literals
---
--------------------------------------------------------------------------
-
-cgLit :: Literal -> FCode CmmLit
-cgLit (MachStr s) = mkByteStringCLit (bytesFS s)
- -- not unpackFS; we want the UTF-8 byte stream.
-cgLit other_lit = return (mkSimpleLit other_lit)
-
-mkSimpleLit :: Literal -> CmmLit
-mkSimpleLit (MachChar c) = CmmInt (fromIntegral (ord c)) wordRep
-mkSimpleLit MachNullAddr = zeroCLit
-mkSimpleLit (MachInt i) = CmmInt i wordRep
-mkSimpleLit (MachInt64 i) = CmmInt i I64
-mkSimpleLit (MachWord i) = CmmInt i wordRep
-mkSimpleLit (MachWord64 i) = CmmInt i I64
-mkSimpleLit (MachFloat r) = CmmFloat r F32
-mkSimpleLit (MachDouble r) = CmmFloat r F64
-mkSimpleLit (MachLabel fs ms) = CmmLabel (mkForeignLabel fs ms is_dyn)
- where
- is_dyn = False -- ToDo: fix me
-
-mkLtOp :: Literal -> MachOp
--- On signed literals we must do a signed comparison
-mkLtOp (MachInt _) = MO_S_Lt wordRep
-mkLtOp (MachFloat _) = MO_S_Lt F32
-mkLtOp (MachDouble _) = MO_S_Lt F64
-mkLtOp lit = MO_U_Lt (cmmLitRep (mkSimpleLit lit))
-
-
----------------------------------------------------
---
--- Cmm data type functions
---
----------------------------------------------------
-
------------------------
--- The "B" variants take byte offsets
-cmmRegOffB :: CmmReg -> ByteOff -> CmmExpr
-cmmRegOffB = cmmRegOff
-
-cmmOffsetB :: CmmExpr -> ByteOff -> CmmExpr
-cmmOffsetB = cmmOffset
-
-cmmOffsetExprB :: CmmExpr -> CmmExpr -> CmmExpr
-cmmOffsetExprB = cmmOffsetExpr
-
-cmmLabelOffB :: CLabel -> ByteOff -> CmmLit
-cmmLabelOffB = cmmLabelOff
-
-cmmOffsetLitB :: CmmLit -> ByteOff -> CmmLit
-cmmOffsetLitB = cmmOffsetLit
-
------------------------
--- The "W" variants take word offsets
-cmmOffsetExprW :: CmmExpr -> CmmExpr -> CmmExpr
--- The second arg is a *word* offset; need to change it to bytes
-cmmOffsetExprW e (CmmLit (CmmInt n _)) = cmmOffsetW e (fromInteger n)
-cmmOffsetExprW e wd_off = cmmIndexExpr wordRep e wd_off
-
-cmmOffsetW :: CmmExpr -> WordOff -> CmmExpr
-cmmOffsetW e n = cmmOffsetB e (wORD_SIZE * n)
-
-cmmRegOffW :: CmmReg -> WordOff -> CmmExpr
-cmmRegOffW reg wd_off = cmmRegOffB reg (wd_off * wORD_SIZE)
-
-cmmOffsetLitW :: CmmLit -> WordOff -> CmmLit
-cmmOffsetLitW lit wd_off = cmmOffsetLitB lit (wORD_SIZE * wd_off)
-
-cmmLabelOffW :: CLabel -> WordOff -> CmmLit
-cmmLabelOffW lbl wd_off = cmmLabelOffB lbl (wORD_SIZE * wd_off)
-
-cmmLoadIndexW :: CmmExpr -> Int -> CmmExpr
-cmmLoadIndexW base off
- = CmmLoad (cmmOffsetW base off) wordRep
-
------------------------
-cmmNeWord, cmmEqWord, cmmOrWord, cmmAndWord :: CmmExpr -> CmmExpr -> CmmExpr
-cmmOrWord e1 e2 = CmmMachOp mo_wordOr [e1, e2]
-cmmAndWord e1 e2 = CmmMachOp mo_wordAnd [e1, e2]
-cmmNeWord e1 e2 = CmmMachOp mo_wordNe [e1, e2]
-cmmEqWord e1 e2 = CmmMachOp mo_wordEq [e1, e2]
-cmmULtWord e1 e2 = CmmMachOp mo_wordULt [e1, e2]
-cmmUGeWord e1 e2 = CmmMachOp mo_wordUGe [e1, e2]
-cmmUGtWord e1 e2 = CmmMachOp mo_wordUGt [e1, e2]
-
-cmmNegate :: CmmExpr -> CmmExpr
-cmmNegate (CmmLit (CmmInt n rep)) = CmmLit (CmmInt (-n) rep)
-cmmNegate e = CmmMachOp (MO_S_Neg (cmmExprRep e)) [e]
-
-blankWord :: CmmStatic
-blankWord = CmmUninitialised wORD_SIZE
-
------------------------
--- Making literals
-
-mkWordCLit :: StgWord -> CmmLit
-mkWordCLit wd = CmmInt (fromIntegral wd) wordRep
-
-packHalfWordsCLit :: (Integral a, Integral b) => a -> b -> CmmLit
--- Make a single word literal in which the lower_half_word is
--- at the lower address, and the upper_half_word is at the
--- higher address
--- ToDo: consider using half-word lits instead
--- but be careful: that's vulnerable when reversed
-packHalfWordsCLit lower_half_word upper_half_word
-#ifdef WORDS_BIGENDIAN
- = mkWordCLit ((fromIntegral lower_half_word `shiftL` hALF_WORD_SIZE_IN_BITS)
- .|. fromIntegral upper_half_word)
-#else
- = mkWordCLit ((fromIntegral lower_half_word)
- .|. (fromIntegral upper_half_word `shiftL` hALF_WORD_SIZE_IN_BITS))
-#endif
-
---------------------------------------------------------------------------
---
--- Incrementing a memory location
---
---------------------------------------------------------------------------
-
-addToMem :: MachRep -- rep of the counter
- -> CmmExpr -- Address
- -> Int -- What to add (a word)
- -> CmmStmt
-addToMem rep ptr n = addToMemE rep ptr (CmmLit (CmmInt (toInteger n) rep))
-
-addToMemE :: MachRep -- rep of the counter
- -> CmmExpr -- Address
- -> CmmExpr -- What to add (a word-typed expression)
- -> CmmStmt
-addToMemE rep ptr n
- = CmmStore ptr (CmmMachOp (MO_Add rep) [CmmLoad ptr rep, n])
-
--------------------------------------------------------------------------
---
--- Converting a closure tag to a closure for enumeration types
--- (this is the implementation of tagToEnum#).
---
--------------------------------------------------------------------------
-
-tagToClosure :: HomeModules -> TyCon -> CmmExpr -> CmmExpr
-tagToClosure hmods tycon tag
- = CmmLoad (cmmOffsetExprW closure_tbl tag) wordRep
- where closure_tbl = CmmLit (CmmLabel lbl)
- lbl = mkClosureTableLabel hmods (tyConName tycon)
-
--------------------------------------------------------------------------
---
--- Conditionals and rts calls
---
--------------------------------------------------------------------------
-
-emitIf :: CmmExpr -- Boolean
- -> Code -- Then part
- -> Code
--- Emit (if e then x)
--- ToDo: reverse the condition to avoid the extra branch instruction if possible
--- (some conditionals aren't reversible. eg. floating point comparisons cannot
--- be inverted because there exist some values for which both comparisons
--- return False, such as NaN.)
-emitIf cond then_part
- = do { then_id <- newLabelC
- ; join_id <- newLabelC
- ; stmtC (CmmCondBranch cond then_id)
- ; stmtC (CmmBranch join_id)
- ; labelC then_id
- ; then_part
- ; labelC join_id
- }
-
-emitIfThenElse :: CmmExpr -- Boolean
- -> Code -- Then part
- -> Code -- Else part
- -> Code
--- Emit (if e then x else y)
-emitIfThenElse cond then_part else_part
- = do { then_id <- newLabelC
- ; else_id <- newLabelC
- ; join_id <- newLabelC
- ; stmtC (CmmCondBranch cond then_id)
- ; else_part
- ; stmtC (CmmBranch join_id)
- ; labelC then_id
- ; then_part
- ; labelC join_id
- }
-
-emitRtsCall :: LitString -> [(CmmExpr,MachHint)] -> Code
-emitRtsCall fun args = emitRtsCall' [] fun args Nothing
- -- The 'Nothing' says "save all global registers"
-
-emitRtsCallWithVols :: LitString -> [(CmmExpr,MachHint)] -> [GlobalReg] -> Code
-emitRtsCallWithVols fun args vols
- = emitRtsCall' [] fun args (Just vols)
-
-emitRtsCallWithResult :: CmmReg -> MachHint -> LitString
- -> [(CmmExpr,MachHint)] -> Code
-emitRtsCallWithResult res hint fun args
- = emitRtsCall' [(res,hint)] fun args Nothing
-
--- Make a call to an RTS C procedure
-emitRtsCall'
- :: [(CmmReg,MachHint)]
- -> LitString
- -> [(CmmExpr,MachHint)]
- -> Maybe [GlobalReg]
- -> Code
-emitRtsCall' res fun args vols = stmtC (CmmCall target res args vols)
- where
- target = CmmForeignCall fun_expr CCallConv
- fun_expr = mkLblExpr (mkRtsCodeLabel fun)
-
-
--------------------------------------------------------------------------
---
--- Strings gnerate a top-level data block
---
--------------------------------------------------------------------------
-
-emitDataLits :: CLabel -> [CmmLit] -> Code
--- Emit a data-segment data block
-emitDataLits lbl lits
- = emitData Data (CmmDataLabel lbl : map CmmStaticLit lits)
-
-emitRODataLits :: CLabel -> [CmmLit] -> Code
--- Emit a read-only data block
-emitRODataLits lbl lits
- = emitData section (CmmDataLabel lbl : map CmmStaticLit lits)
- where section | any needsRelocation lits = RelocatableReadOnlyData
- | otherwise = ReadOnlyData
- needsRelocation (CmmLabel _) = True
- needsRelocation (CmmLabelOff _ _) = True
- needsRelocation _ = False
-
-mkStringCLit :: String -> FCode CmmLit
--- Make a global definition for the string,
--- and return its label
-mkStringCLit str = mkByteStringCLit (map (fromIntegral.ord) str)
-
-mkByteStringCLit :: [Word8] -> FCode CmmLit
-mkByteStringCLit bytes
- = do { uniq <- newUnique
- ; let lbl = mkStringLitLabel uniq
- ; emitData ReadOnlyData [CmmDataLabel lbl, CmmString bytes]
- ; return (CmmLabel lbl) }
-
--------------------------------------------------------------------------
---
--- Assigning expressions to temporaries
---
--------------------------------------------------------------------------
-
-assignTemp :: CmmExpr -> FCode CmmExpr
--- For a non-trivial expression, e, create a local
--- variable and assign the expression to it
-assignTemp e
- | isTrivialCmmExpr e = return e
- | otherwise = do { reg <- newTemp (cmmExprRep e)
- ; stmtC (CmmAssign reg e)
- ; return (CmmReg reg) }
-
-
-newTemp :: MachRep -> FCode CmmReg
-newTemp rep = do { uniq <- newUnique; return (CmmLocal (LocalReg uniq rep)) }
-
-
--------------------------------------------------------------------------
---
--- Building case analysis
---
--------------------------------------------------------------------------
-
-emitSwitch
- :: CmmExpr -- Tag to switch on
- -> [(ConTagZ, CgStmts)] -- Tagged branches
- -> Maybe CgStmts -- Default branch (if any)
- -> ConTagZ -> ConTagZ -- Min and Max possible values; behaviour
- -- outside this range is undefined
- -> Code
-
--- ONLY A DEFAULT BRANCH: no case analysis to do
-emitSwitch tag_expr [] (Just stmts) _ _
- = emitCgStmts stmts
-
--- Right, off we go
-emitSwitch tag_expr branches mb_deflt lo_tag hi_tag
- = -- Just sort the branches before calling mk_sritch
- do { mb_deflt_id <-
- case mb_deflt of
- Nothing -> return Nothing
- Just stmts -> do id <- forkCgStmts stmts; return (Just id)
-
- ; dflags <- getDynFlags
- ; let via_C | HscC <- hscTarget dflags = True
- | otherwise = False
-
- ; stmts <- mk_switch tag_expr (sortLe le branches)
- mb_deflt_id lo_tag hi_tag via_C
- ; emitCgStmts stmts
- }
- where
- (t1,_) `le` (t2,_) = t1 <= t2
-
-
-mk_switch :: CmmExpr -> [(ConTagZ, CgStmts)]
- -> Maybe BlockId -> ConTagZ -> ConTagZ -> Bool
- -> FCode CgStmts
-
--- SINGLETON TAG RANGE: no case analysis to do
-mk_switch tag_expr [(tag,stmts)] _ lo_tag hi_tag via_C
- | lo_tag == hi_tag
- = ASSERT( tag == lo_tag )
- return stmts
-
--- SINGLETON BRANCH, NO DEFUALT: no case analysis to do
-mk_switch tag_expr [(tag,stmts)] Nothing lo_tag hi_tag via_C
- = return stmts
- -- The simplifier might have eliminated a case
- -- so we may have e.g. case xs of
- -- [] -> e
- -- In that situation we can be sure the (:) case
- -- can't happen, so no need to test
-
--- SINGLETON BRANCH: one equality check to do
-mk_switch tag_expr [(tag,stmts)] (Just deflt) lo_tag hi_tag via_C
- = return (CmmCondBranch cond deflt `consCgStmt` stmts)
- where
- cond = cmmNeWord tag_expr (CmmLit (mkIntCLit tag))
- -- We have lo_tag < hi_tag, but there's only one branch,
- -- so there must be a default
-
--- ToDo: we might want to check for the two branch case, where one of
--- the branches is the tag 0, because comparing '== 0' is likely to be
--- more efficient than other kinds of comparison.
-
--- DENSE TAG RANGE: use a switch statment.
---
--- We also use a switch uncoditionally when compiling via C, because
--- this will get emitted as a C switch statement and the C compiler
--- should do a good job of optimising it. Also, older GCC versions
--- (2.95 in particular) have problems compiling the complicated
--- if-trees generated by this code, so compiling to a switch every
--- time works around that problem.
---
-mk_switch tag_expr branches mb_deflt lo_tag hi_tag via_C
- | use_switch -- Use a switch
- = do { branch_ids <- mapM forkCgStmts (map snd branches)
- ; let
- tagged_blk_ids = zip (map fst branches) (map Just branch_ids)
-
- find_branch :: ConTagZ -> Maybe BlockId
- find_branch i = assocDefault mb_deflt tagged_blk_ids i
-
- -- NB. we have eliminated impossible branches at
- -- either end of the range (see below), so the first
- -- tag of a real branch is real_lo_tag (not lo_tag).
- arms = [ find_branch i | i <- [real_lo_tag..real_hi_tag]]
-
- switch_stmt = CmmSwitch (cmmOffset tag_expr (- real_lo_tag)) arms
-
- ; ASSERT(not (all isNothing arms))
- return (oneCgStmt switch_stmt)
- }
-
- -- if we can knock off a bunch of default cases with one if, then do so
- | Just deflt <- mb_deflt, (lowest_branch - lo_tag) >= n_branches
- = do { (assign_tag, tag_expr') <- assignTemp' tag_expr
- ; let cond = cmmULtWord tag_expr' (CmmLit (mkIntCLit lowest_branch))
- branch = CmmCondBranch cond deflt
- ; stmts <- mk_switch tag_expr' branches mb_deflt
- lowest_branch hi_tag via_C
- ; return (assign_tag `consCgStmt` (branch `consCgStmt` stmts))
- }
-
- | Just deflt <- mb_deflt, (hi_tag - highest_branch) >= n_branches
- = do { (assign_tag, tag_expr') <- assignTemp' tag_expr
- ; let cond = cmmUGtWord tag_expr' (CmmLit (mkIntCLit highest_branch))
- branch = CmmCondBranch cond deflt
- ; stmts <- mk_switch tag_expr' branches mb_deflt
- lo_tag highest_branch via_C
- ; return (assign_tag `consCgStmt` (branch `consCgStmt` stmts))
- }
-
- | otherwise -- Use an if-tree
- = do { (assign_tag, tag_expr') <- assignTemp' tag_expr
- -- To avoid duplication
- ; lo_stmts <- mk_switch tag_expr' lo_branches mb_deflt
- lo_tag (mid_tag-1) via_C
- ; hi_stmts <- mk_switch tag_expr' hi_branches mb_deflt
- mid_tag hi_tag via_C
- ; hi_id <- forkCgStmts hi_stmts
- ; let cond = cmmUGeWord tag_expr' (CmmLit (mkIntCLit mid_tag))
- branch_stmt = CmmCondBranch cond hi_id
- ; return (assign_tag `consCgStmt` (branch_stmt `consCgStmt` lo_stmts))
- }
- -- we test (e >= mid_tag) rather than (e < mid_tag), because
- -- the former works better when e is a comparison, and there
- -- are two tags 0 & 1 (mid_tag == 1). In this case, the code
- -- generator can reduce the condition to e itself without
- -- having to reverse the sense of the comparison: comparisons
- -- can't always be easily reversed (eg. floating
- -- pt. comparisons).
- where
- use_switch = {- pprTrace "mk_switch" (
- ppr tag_expr <+> text "n_tags:" <+> int n_tags <+>
- text "n_branches:" <+> int n_branches <+>
- text "lo_tag: " <+> int lo_tag <+>
- text "hi_tag: " <+> int hi_tag <+>
- text "real_lo_tag: " <+> int real_lo_tag <+>
- text "real_hi_tag: " <+> int real_hi_tag) $ -}
- ASSERT( n_branches > 1 && n_tags > 1 )
- n_tags > 2 && (small || dense || via_C)
- -- a 2-branch switch always turns into an if.
- small = n_tags <= 4
- dense = n_branches > (n_tags `div` 2)
- exhaustive = n_tags == n_branches
- n_branches = length branches
-
- -- ignore default slots at each end of the range if there's
- -- no default branch defined.
- lowest_branch = fst (head branches)
- highest_branch = fst (last branches)
-
- real_lo_tag
- | isNothing mb_deflt = lowest_branch
- | otherwise = lo_tag
-
- real_hi_tag
- | isNothing mb_deflt = highest_branch
- | otherwise = hi_tag
-
- n_tags = real_hi_tag - real_lo_tag + 1
-
- -- INVARIANT: Provided hi_tag > lo_tag (which is true)
- -- lo_tag <= mid_tag < hi_tag
- -- lo_branches have tags < mid_tag
- -- hi_branches have tags >= mid_tag
-
- (mid_tag,_) = branches !! (n_branches `div` 2)
- -- 2 branches => n_branches `div` 2 = 1
- -- => branches !! 1 give the *second* tag
- -- There are always at least 2 branches here
-
- (lo_branches, hi_branches) = span is_lo branches
- is_lo (t,_) = t < mid_tag
-
-
-assignTemp' e
- | isTrivialCmmExpr e = return (CmmNop, e)
- | otherwise = do { reg <- newTemp (cmmExprRep e)
- ; return (CmmAssign reg e, CmmReg reg) }
-
-
-emitLitSwitch :: CmmExpr -- Tag to switch on
- -> [(Literal, CgStmts)] -- Tagged branches
- -> CgStmts -- Default branch (always)
- -> Code -- Emit the code
--- Used for general literals, whose size might not be a word,
--- where there is always a default case, and where we don't know
--- the range of values for certain. For simplicity we always generate a tree.
---
--- ToDo: for integers we could do better here, perhaps by generalising
--- mk_switch and using that. --SDM 15/09/2004
-emitLitSwitch scrut [] deflt
- = emitCgStmts deflt
-emitLitSwitch scrut branches deflt_blk
- = do { scrut' <- assignTemp scrut
- ; deflt_blk_id <- forkCgStmts deflt_blk
- ; blk <- mk_lit_switch scrut' deflt_blk_id (sortLe le branches)
- ; emitCgStmts blk }
- where
- le (t1,_) (t2,_) = t1 <= t2
-
-mk_lit_switch :: CmmExpr -> BlockId
- -> [(Literal,CgStmts)]
- -> FCode CgStmts
-mk_lit_switch scrut deflt_blk_id [(lit,blk)]
- = return (consCgStmt if_stmt blk)
- where
- cmm_lit = mkSimpleLit lit
- rep = cmmLitRep cmm_lit
- cond = CmmMachOp (MO_Ne rep) [scrut, CmmLit cmm_lit]
- if_stmt = CmmCondBranch cond deflt_blk_id
-
-mk_lit_switch scrut deflt_blk_id branches
- = do { hi_blk <- mk_lit_switch scrut deflt_blk_id hi_branches
- ; lo_blk <- mk_lit_switch scrut deflt_blk_id lo_branches
- ; lo_blk_id <- forkCgStmts lo_blk
- ; let if_stmt = CmmCondBranch cond lo_blk_id
- ; return (if_stmt `consCgStmt` hi_blk) }
- where
- n_branches = length branches
- (mid_lit,_) = branches !! (n_branches `div` 2)
- -- See notes above re mid_tag
-
- (lo_branches, hi_branches) = span is_lo branches
- is_lo (t,_) = t < mid_lit
-
- cond = CmmMachOp (mkLtOp mid_lit)
- [scrut, CmmLit (mkSimpleLit mid_lit)]
-
--------------------------------------------------------------------------
---
--- Simultaneous assignment
---
--------------------------------------------------------------------------
-
-
-emitSimultaneously :: CmmStmts -> Code
--- Emit code to perform the assignments in the
--- input simultaneously, using temporary variables when necessary.
---
--- The Stmts must be:
--- CmmNop, CmmComment, CmmAssign, CmmStore
--- and nothing else
-
-
--- We use the strongly-connected component algorithm, in which
--- * the vertices are the statements
--- * an edge goes from s1 to s2 iff
--- s1 assigns to something s2 uses
--- that is, if s1 should *follow* s2 in the final order
-
-type CVertex = (Int, CmmStmt) -- Give each vertex a unique number,
- -- for fast comparison
-
-emitSimultaneously stmts
- = codeOnly $
- case filterOut isNopStmt (stmtList stmts) of
- -- Remove no-ops
- [] -> nopC
- [stmt] -> stmtC stmt -- It's often just one stmt
- stmt_list -> doSimultaneously1 (zip [(1::Int)..] stmt_list)
-
-doSimultaneously1 :: [CVertex] -> Code
-doSimultaneously1 vertices
- = let
- edges = [ (vertex, key1, edges_from stmt1)
- | vertex@(key1, stmt1) <- vertices
- ]
- edges_from stmt1 = [ key2 | (key2, stmt2) <- vertices,
- stmt1 `mustFollow` stmt2
- ]
- components = stronglyConnComp edges
-
- -- do_components deal with one strongly-connected component
- -- Not cyclic, or singleton? Just do it
- do_component (AcyclicSCC (n,stmt)) = stmtC stmt
- do_component (CyclicSCC [(n,stmt)]) = stmtC stmt
-
- -- Cyclic? Then go via temporaries. Pick one to
- -- break the loop and try again with the rest.
- do_component (CyclicSCC ((n,first_stmt) : rest))
- = do { from_temp <- go_via_temp first_stmt
- ; doSimultaneously1 rest
- ; stmtC from_temp }
-
- go_via_temp (CmmAssign dest src)
- = do { tmp <- newTemp (cmmRegRep dest)
- ; stmtC (CmmAssign tmp src)
- ; return (CmmAssign dest (CmmReg tmp)) }
- go_via_temp (CmmStore dest src)
- = do { tmp <- newTemp (cmmExprRep src)
- ; stmtC (CmmAssign tmp src)
- ; return (CmmStore dest (CmmReg tmp)) }
- in
- mapCs do_component components
-
-mustFollow :: CmmStmt -> CmmStmt -> Bool
-CmmAssign reg _ `mustFollow` stmt = anySrc (reg `regUsedIn`) stmt
-CmmStore loc e `mustFollow` stmt = anySrc (locUsedIn loc (cmmExprRep e)) stmt
-CmmNop `mustFollow` stmt = False
-CmmComment _ `mustFollow` stmt = False
-
-
-anySrc :: (CmmExpr -> Bool) -> CmmStmt -> Bool
--- True if the fn is true of any input of the stmt
-anySrc p (CmmAssign _ e) = p e
-anySrc p (CmmStore e1 e2) = p e1 || p e2 -- Might be used in either side
-anySrc p (CmmComment _) = False
-anySrc p CmmNop = False
-anySrc p other = True -- Conservative
-
-regUsedIn :: CmmReg -> CmmExpr -> Bool
-reg `regUsedIn` CmmLit _ = False
-reg `regUsedIn` CmmLoad e _ = reg `regUsedIn` e
-reg `regUsedIn` CmmReg reg' = reg == reg'
-reg `regUsedIn` CmmRegOff reg' _ = reg == reg'
-reg `regUsedIn` CmmMachOp _ es = any (reg `regUsedIn`) es
-
-locUsedIn :: CmmExpr -> MachRep -> CmmExpr -> Bool
--- (locUsedIn a r e) checks whether writing to r[a] could affect the value of
--- 'e'. Returns True if it's not sure.
-locUsedIn loc rep (CmmLit _) = False
-locUsedIn loc rep (CmmLoad e ld_rep) = possiblySameLoc loc rep e ld_rep
-locUsedIn loc rep (CmmReg reg') = False
-locUsedIn loc rep (CmmRegOff reg' _) = False
-locUsedIn loc rep (CmmMachOp _ es) = any (locUsedIn loc rep) es
-
-possiblySameLoc :: CmmExpr -> MachRep -> CmmExpr -> MachRep -> Bool
--- Assumes that distinct registers (eg Hp, Sp) do not
--- point to the same location, nor any offset thereof.
-possiblySameLoc (CmmReg r1) rep1 (CmmReg r2) rep2 = r1==r2
-possiblySameLoc (CmmReg r1) rep1 (CmmRegOff r2 0) rep2 = r1==r2
-possiblySameLoc (CmmRegOff r1 0) rep1 (CmmReg r2) rep2 = r1==r2
-possiblySameLoc (CmmRegOff r1 start1) rep1 (CmmRegOff r2 start2) rep2
- = r1==r2 && end1 > start2 && end2 > start1
- where
- end1 = start1 + machRepByteWidth rep1
- end2 = start2 + machRepByteWidth rep2
-
-possiblySameLoc l1 rep1 (CmmLit _) rep2 = False
-possiblySameLoc l1 rep1 l2 rep2 = True -- Conservative
projects / ghc-hetmet.git / blobdiff