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Diffstat (limited to 'compiler/codeGen/StgCmmClosure.hs')
| -rw-r--r-- | compiler/codeGen/StgCmmClosure.hs | 1100 |
1 files changed, 1100 insertions, 0 deletions
diff --git a/compiler/codeGen/StgCmmClosure.hs b/compiler/codeGen/StgCmmClosure.hs new file mode 100644 index 0000000000..c32d7cd857 --- /dev/null +++ b/compiler/codeGen/StgCmmClosure.hs @@ -0,0 +1,1100 @@ +----------------------------------------------------------------------------- +-- +-- Stg to C-- code generation: +-- +-- The types LambdaFormInfo +-- ClosureInfo +-- +-- Nothing monadic in here! +-- +-- (c) The University of Glasgow 2004-2006 +-- +----------------------------------------------------------------------------- + + +module StgCmmClosure ( + SMRep, + DynTag, tagForCon, isSmallFamily, + ConTagZ, dataConTagZ, + + ArgDescr(..), Liveness(..), + C_SRT(..), needsSRT, + + isVoidRep, isGcPtrRep, addIdReps, addArgReps, + argPrimRep, + + LambdaFormInfo, -- Abstract + StandardFormInfo, -- ...ditto... + mkLFThunk, mkLFReEntrant, mkConLFInfo, mkSelectorLFInfo, + mkApLFInfo, mkLFImported, mkLFArgument, mkLFLetNoEscape, + lfDynTag, + + ClosureInfo, + mkClosureInfo, mkConInfo, maybeIsLFCon, + + closureSize, closureNonHdrSize, + closureGoodStuffSize, closurePtrsSize, + slopSize, + + closureName, infoTableLabelFromCI, + closureLabelFromCI, + closureTypeInfo, + closureLFInfo, isLFThunk,closureSMRep, closureUpdReqd, + closureNeedsUpdSpace, closureIsThunk, + closureSingleEntry, closureReEntrant, isConstrClosure_maybe, + closureFunInfo, isStandardFormThunk, isKnownFun, + funTag, tagForArity, + + enterIdLabel, enterLocalIdLabel, + + nodeMustPointToIt, + CallMethod(..), getCallMethod, + + blackHoleOnEntry, + + getClosureType, + + isToplevClosure, + closureValDescr, closureTypeDescr, -- profiling + + isStaticClosure, + cafBlackHoleClosureInfo, seCafBlackHoleClosureInfo, + + staticClosureNeedsLink, clHasCafRefs + ) where + +#include "../includes/MachDeps.h" + +#define FAST_STRING_NOT_NEEDED +#include "HsVersions.h" + +import ClosureInfo (ArgDescr(..), C_SRT(..), Liveness(..)) + -- XXX temporary becuase FunInfo needs this one + +import StgSyn +import SMRep +import Cmm ( ClosureTypeInfo(..) ) +import CmmExpr + +import CLabel +import StaticFlags +import Id +import IdInfo +import DataCon +import Name +import OccName +import Type +import TypeRep +import TcType +import TyCon +import BasicTypes +import Outputable +import Constants + + +----------------------------------------------------------------------------- +-- Representations +----------------------------------------------------------------------------- + +addIdReps :: [Id] -> [(PrimRep, Id)] +addIdReps ids = [(idPrimRep id, id) | id <- ids] + +addArgReps :: [StgArg] -> [(PrimRep, StgArg)] +addArgReps args = [(argPrimRep arg, arg) | arg <- args] + +argPrimRep :: StgArg -> PrimRep +argPrimRep arg = typePrimRep (stgArgType arg) + +isVoidRep :: PrimRep -> Bool +isVoidRep VoidRep = True +isVoidRep _other = False + +isGcPtrRep :: PrimRep -> Bool +isGcPtrRep PtrRep = True +isGcPtrRep _ = False + + +----------------------------------------------------------------------------- +-- LambdaFormInfo +----------------------------------------------------------------------------- + +-- Information about an identifier, from the code generator's point of +-- view. Every identifier is bound to a LambdaFormInfo in the +-- environment, which gives the code generator enough info to be able to +-- tail call or return that identifier. + +data LambdaFormInfo + = LFReEntrant -- Reentrant closure (a function) + TopLevelFlag -- True if top level + !Int -- Arity. Invariant: always > 0 + !Bool -- True <=> no fvs + ArgDescr -- Argument descriptor (should really be in ClosureInfo) + + | LFThunk -- Thunk (zero arity) + TopLevelFlag + !Bool -- True <=> no free vars + !Bool -- True <=> updatable (i.e., *not* single-entry) + StandardFormInfo + !Bool -- True <=> *might* be a function type + + | LFCon -- A saturated constructor application + DataCon -- The constructor + + | LFUnknown -- Used for function arguments and imported things. + -- We know nothing about this closure. + -- Treat like updatable "LFThunk"... + -- Imported things which we *do* know something about use + -- one of the other LF constructors (eg LFReEntrant for + -- known functions) + !Bool -- True <=> *might* be a function type + -- The False case is good when we want to enter it, + -- because then we know the entry code will do + -- For a function, the entry code is the fast entry point + + | LFUnLifted -- A value of unboxed type; + -- always a value, neeeds evaluation + + | LFLetNoEscape -- See LetNoEscape module for precise description + + | LFBlackHole -- Used for the closures allocated to hold the result + -- of a CAF. We want the target of the update frame to + -- be in the heap, so we make a black hole to hold it. + CLabel -- Flavour (info label, eg CAF_BLACKHOLE_info). + + +------------------------- +-- An ArgDsecr describes the argument pattern of a function + +{- XXX -- imported from old ClosureInfo for now +data ArgDescr + = ArgSpec -- Fits one of the standard patterns + !StgHalfWord -- RTS type identifier ARG_P, ARG_N, ... + + | ArgGen -- General case + Liveness -- Details about the arguments +-} + +{- XXX -- imported from old ClosureInfo for now +------------------------- +-- We represent liveness bitmaps as a Bitmap (whose internal +-- representation really is a bitmap). These are pinned onto case return +-- vectors to indicate the state of the stack for the garbage collector. +-- +-- In the compiled program, liveness bitmaps that fit inside a single +-- word (StgWord) are stored as a single word, while larger bitmaps are +-- stored as a pointer to an array of words. + +data Liveness + = SmallLiveness -- Liveness info that fits in one word + StgWord -- Here's the bitmap + + | BigLiveness -- Liveness info witha a multi-word bitmap + CLabel -- Label for the bitmap +-} + +------------------------- +-- StandardFormInfo tells whether this thunk has one of +-- a small number of standard forms + +data StandardFormInfo + = NonStandardThunk + -- Not of of the standard forms + + | SelectorThunk + -- A SelectorThunk is of form + -- case x of + -- con a1,..,an -> ak + -- and the constructor is from a single-constr type. + WordOff -- 0-origin offset of ak within the "goods" of + -- constructor (Recall that the a1,...,an may be laid + -- out in the heap in a non-obvious order.) + + | ApThunk + -- An ApThunk is of form + -- x1 ... xn + -- The code for the thunk just pushes x2..xn on the stack and enters x1. + -- There are a few of these (for 1 <= n <= MAX_SPEC_AP_SIZE) pre-compiled + -- in the RTS to save space. + Int -- Arity, n + + +------------------------------------------------------ +-- Building LambdaFormInfo +------------------------------------------------------ + +mkLFArgument :: Id -> LambdaFormInfo +mkLFArgument id + | isUnLiftedType ty = LFUnLifted + | might_be_a_function ty = LFUnknown True + | otherwise = LFUnknown False + where + ty = idType id + +------------- +mkLFLetNoEscape :: LambdaFormInfo +mkLFLetNoEscape = LFLetNoEscape + +------------- +mkLFReEntrant :: TopLevelFlag -- True of top level + -> [Id] -- Free vars + -> [Id] -- Args + -> ArgDescr -- Argument descriptor + -> LambdaFormInfo + +mkLFReEntrant top fvs args arg_descr + = LFReEntrant top (length args) (null fvs) arg_descr + +------------- +mkLFThunk :: Type -> TopLevelFlag -> [Id] -> UpdateFlag -> LambdaFormInfo +mkLFThunk thunk_ty top fvs upd_flag + = ASSERT( not (isUpdatable upd_flag) || not (isUnLiftedType thunk_ty) ) + LFThunk top (null fvs) + (isUpdatable upd_flag) + NonStandardThunk + (might_be_a_function thunk_ty) + +-------------- +might_be_a_function :: Type -> Bool +-- Return False only if we are *sure* it's a data type +-- Look through newtypes etc as much as poss +might_be_a_function ty + = case splitTyConApp_maybe (repType ty) of + Just (tc, _) -> not (isDataTyCon tc) + Nothing -> True + +------------- +mkConLFInfo :: DataCon -> LambdaFormInfo +mkConLFInfo con = LFCon con + +------------- +mkSelectorLFInfo :: Id -> Int -> Bool -> LambdaFormInfo +mkSelectorLFInfo id offset updatable + = LFThunk NotTopLevel False updatable (SelectorThunk offset) + (might_be_a_function (idType id)) + +------------- +mkApLFInfo :: Id -> UpdateFlag -> Arity -> LambdaFormInfo +mkApLFInfo id upd_flag arity + = LFThunk NotTopLevel (arity == 0) (isUpdatable upd_flag) (ApThunk arity) + (might_be_a_function (idType id)) + +------------- +mkLFImported :: Id -> LambdaFormInfo +mkLFImported id + | Just con <- isDataConWorkId_maybe id + , isNullaryRepDataCon con + = LFCon con -- An imported nullary constructor + -- We assume that the constructor is evaluated so that + -- the id really does point directly to the constructor + + | arity > 0 + = LFReEntrant TopLevel arity True (panic "arg_descr") + + | otherwise + = mkLFArgument id -- Not sure of exact arity + where + arity = idArity id + +----------------------------------------------------- +-- Dynamic pointer tagging +----------------------------------------------------- + +type ConTagZ = Int -- A *zero-indexed* contructor tag + +type DynTag = Int -- The tag on a *pointer* + -- (from the dynamic-tagging paper) + +{- Note [Data constructor dynamic tags] + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The family size of a data type (the number of constructors) +can be either: + * small, if the family size < 2**tag_bits + * big, otherwise. + +Small families can have the constructor tag in the tag bits. +Big families only use the tag value 1 to represent evaluatedness. -} + +isSmallFamily :: Int -> Bool +isSmallFamily fam_size = fam_size <= mAX_PTR_TAG + +-- We keep the *zero-indexed* tag in the srt_len field of the info +-- table of a data constructor. +dataConTagZ :: DataCon -> ConTagZ +dataConTagZ con = dataConTag con - fIRST_TAG + +tagForCon :: DataCon -> DynTag +tagForCon con + | isSmallFamily fam_size = con_tag + 1 + | otherwise = 1 + where + con_tag = dataConTagZ con + fam_size = tyConFamilySize (dataConTyCon con) + +tagForArity :: Int -> DynTag +tagForArity arity | isSmallFamily arity = arity + | otherwise = 0 + +lfDynTag :: LambdaFormInfo -> DynTag +lfDynTag (LFCon con) = tagForCon con +lfDynTag (LFReEntrant _ arity _ _) = tagForArity arity +lfDynTag _other = 0 + + +----------------------------------------------------------------------------- +-- Observing LambdaFormInfo +----------------------------------------------------------------------------- + +------------- +maybeIsLFCon :: LambdaFormInfo -> Maybe DataCon +maybeIsLFCon (LFCon con) = Just con +maybeIsLFCon _ = Nothing + +------------ +isLFThunk :: LambdaFormInfo -> Bool +isLFThunk (LFThunk _ _ _ _ _) = True +isLFThunk (LFBlackHole _) = True + -- return True for a blackhole: this function is used to determine + -- whether to use the thunk header in SMP mode, and a blackhole + -- must have one. +isLFThunk _ = False + + +----------------------------------------------------------------------------- +-- Choosing SM reps +----------------------------------------------------------------------------- + +chooseSMRep + :: Bool -- True <=> static closure + -> LambdaFormInfo + -> WordOff -> WordOff -- Tot wds, ptr wds + -> SMRep + +chooseSMRep is_static lf_info tot_wds ptr_wds + = let + nonptr_wds = tot_wds - ptr_wds + closure_type = getClosureType is_static ptr_wds lf_info + in + GenericRep is_static ptr_wds nonptr_wds closure_type + +-- We *do* get non-updatable top-level thunks sometimes. eg. f = g +-- gets compiled to a jump to g (if g has non-zero arity), instead of +-- messing around with update frames and PAPs. We set the closure type +-- to FUN_STATIC in this case. + +getClosureType :: Bool -> WordOff -> LambdaFormInfo -> ClosureType +getClosureType is_static ptr_wds lf_info + = case lf_info of + LFCon {} | is_static && ptr_wds == 0 -> ConstrNoCaf + | otherwise -> Constr + LFReEntrant {} -> Fun + LFThunk _ _ _ (SelectorThunk {}) _ -> ThunkSelector + LFThunk {} -> Thunk + _ -> panic "getClosureType" + + +----------------------------------------------------------------------------- +-- nodeMustPointToIt +----------------------------------------------------------------------------- + +-- Be sure to see the stg-details notes about these... + +nodeMustPointToIt :: LambdaFormInfo -> Bool +nodeMustPointToIt (LFReEntrant top _ no_fvs _) + = not no_fvs || -- Certainly if it has fvs we need to point to it + isNotTopLevel top + -- If it is not top level we will point to it + -- We can have a \r closure with no_fvs which + -- is not top level as special case cgRhsClosure + -- has been dissabled in favour of let floating + + -- For lex_profiling we also access the cost centre for a + -- non-inherited function i.e. not top level + -- the not top case above ensures this is ok. + +nodeMustPointToIt (LFCon _) = True + + -- Strictly speaking, the above two don't need Node to point + -- to it if the arity = 0. But this is a *really* unlikely + -- situation. If we know it's nil (say) and we are entering + -- it. Eg: let x = [] in x then we will certainly have inlined + -- x, since nil is a simple atom. So we gain little by not + -- having Node point to known zero-arity things. On the other + -- hand, we do lose something; Patrick's code for figuring out + -- when something has been updated but not entered relies on + -- having Node point to the result of an update. SLPJ + -- 27/11/92. + +nodeMustPointToIt (LFThunk _ no_fvs updatable NonStandardThunk _) + = updatable || not no_fvs || opt_SccProfilingOn + -- For the non-updatable (single-entry case): + -- + -- True if has fvs (in which case we need access to them, and we + -- should black-hole it) + -- or profiling (in which case we need to recover the cost centre + -- from inside it) + +nodeMustPointToIt (LFThunk {}) -- Node must point to a standard-form thunk + = True + +nodeMustPointToIt (LFUnknown _) = True +nodeMustPointToIt LFUnLifted = False +nodeMustPointToIt (LFBlackHole _) = True -- BH entry may require Node to point +nodeMustPointToIt LFLetNoEscape = False + +----------------------------------------------------------------------------- +-- getCallMethod +----------------------------------------------------------------------------- + +{- The entry conventions depend on the type of closure being entered, +whether or not it has free variables, and whether we're running +sequentially or in parallel. + +Closure Node Argument Enter +Characteristics Par Req'd Passing Via +------------------------------------------------------------------------------- +Unknown & no & yes & stack & node +Known fun (>1 arg), no fvs & no & no & registers & fast entry (enough args) + & slow entry (otherwise) +Known fun (>1 arg), fvs & no & yes & registers & fast entry (enough args) +0 arg, no fvs \r,\s & no & no & n/a & direct entry +0 arg, no fvs \u & no & yes & n/a & node +0 arg, fvs \r,\s & no & yes & n/a & direct entry +0 arg, fvs \u & no & yes & n/a & node + +Unknown & yes & yes & stack & node +Known fun (>1 arg), no fvs & yes & no & registers & fast entry (enough args) + & slow entry (otherwise) +Known fun (>1 arg), fvs & yes & yes & registers & node +0 arg, no fvs \r,\s & yes & no & n/a & direct entry +0 arg, no fvs \u & yes & yes & n/a & node +0 arg, fvs \r,\s & yes & yes & n/a & node +0 arg, fvs \u & yes & yes & n/a & node +\end{tabular} + +When black-holing, single-entry closures could also be entered via node +(rather than directly) to catch double-entry. -} + +data CallMethod + = EnterIt -- No args, not a function + + | JumpToIt -- A join point + + | ReturnIt -- It's a value (function, unboxed value, + -- or constructor), so just return it. + + | SlowCall -- Unknown fun, or known fun with + -- too few args. + + | DirectEntry -- Jump directly, with args in regs + CLabel -- The code label + Int -- Its arity + +getCallMethod :: Name -- Function being applied + -> CafInfo -- Can it refer to CAF's? + -> LambdaFormInfo -- Its info + -> Int -- Number of available arguments + -> CallMethod + +getCallMethod _name _ lf_info _n_args + | nodeMustPointToIt lf_info && opt_Parallel + = -- If we're parallel, then we must always enter via node. + -- The reason is that the closure may have been + -- fetched since we allocated it. + EnterIt + +getCallMethod name caf (LFReEntrant _ arity _ _) n_args + | n_args == 0 = ASSERT( arity /= 0 ) + ReturnIt -- No args at all + | n_args < arity = SlowCall -- Not enough args + | otherwise = DirectEntry (enterIdLabel name caf) arity + +getCallMethod _name _ LFUnLifted n_args + = ASSERT( n_args == 0 ) ReturnIt + +getCallMethod _name _ (LFCon _) n_args + = ASSERT( n_args == 0 ) ReturnIt + +getCallMethod name caf (LFThunk _ _ updatable std_form_info is_fun) n_args + | is_fun -- it *might* be a function, so we must "call" it (which is always safe) + = SlowCall -- We cannot just enter it [in eval/apply, the entry code + -- is the fast-entry code] + + -- Since is_fun is False, we are *definitely* looking at a data value + | updatable || opt_DoTickyProfiling -- to catch double entry + {- OLD: || opt_SMP + I decided to remove this, because in SMP mode it doesn't matter + if we enter the same thunk multiple times, so the optimisation + of jumping directly to the entry code is still valid. --SDM + -} + = EnterIt + -- We used to have ASSERT( n_args == 0 ), but actually it is + -- possible for the optimiser to generate + -- let bot :: Int = error Int "urk" + -- in (bot `cast` unsafeCoerce Int (Int -> Int)) 3 + -- This happens as a result of the case-of-error transformation + -- So the right thing to do is just to enter the thing + + | otherwise -- Jump direct to code for single-entry thunks + = ASSERT( n_args == 0 ) + DirectEntry (thunkEntryLabel name caf std_form_info updatable) 0 + +getCallMethod _name _ (LFUnknown True) _n_args + = SlowCall -- might be a function + +getCallMethod name _ (LFUnknown False) n_args + = ASSERT2 ( n_args == 0, ppr name <+> ppr n_args ) + EnterIt -- Not a function + +getCallMethod _name _ (LFBlackHole _) _n_args + = SlowCall -- Presumably the black hole has by now + -- been updated, but we don't know with + -- what, so we slow call it + +getCallMethod _name _ LFLetNoEscape _n_args + = JumpToIt + +isStandardFormThunk :: LambdaFormInfo -> Bool +isStandardFormThunk (LFThunk _ _ _ (SelectorThunk _) _) = True +isStandardFormThunk (LFThunk _ _ _ (ApThunk _) _) = True +isStandardFormThunk _other_lf_info = False + +isKnownFun :: LambdaFormInfo -> Bool +isKnownFun (LFReEntrant _ _ _ _) = True +isKnownFun LFLetNoEscape = True +isKnownFun _ = False + +----------------------------------------------------------------------------- +-- staticClosureRequired +----------------------------------------------------------------------------- + +{- staticClosureRequired is never called (hence commented out) + + SimonMar writes (Sept 07) It's an optimisation we used to apply at + one time, I believe, but it got lost probably in the rewrite of + the RTS/code generator. I left that code there to remind me to + look into whether it was worth doing sometime + +{- Avoiding generating entries and info tables + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +At present, for every function we generate all of the following, +just in case. But they aren't always all needed, as noted below: + +[NB1: all of this applies only to *functions*. Thunks always +have closure, info table, and entry code.] + +[NB2: All are needed if the function is *exported*, just to play safe.] + +* Fast-entry code ALWAYS NEEDED + +* Slow-entry code + Needed iff (a) we have any un-saturated calls to the function + OR (b) the function is passed as an arg + OR (c) we're in the parallel world and the function has free vars + [Reason: in parallel world, we always enter functions + with free vars via the closure.] + +* The function closure + Needed iff (a) we have any un-saturated calls to the function + OR (b) the function is passed as an arg + OR (c) if the function has free vars (ie not top level) + + Why case (a) here? Because if the arg-satis check fails, + UpdatePAP stuffs a pointer to the function closure in the PAP. + [Could be changed; UpdatePAP could stuff in a code ptr instead, + but doesn't seem worth it.] + + [NB: these conditions imply that we might need the closure + without the slow-entry code. Here's how. + + f x y = let g w = ...x..y..w... + in + ...(g t)... + + Here we need a closure for g which contains x and y, + but since the calls are all saturated we just jump to the + fast entry point for g, with R1 pointing to the closure for g.] + + +* Standard info table + Needed iff (a) we have any un-saturated calls to the function + OR (b) the function is passed as an arg + OR (c) the function has free vars (ie not top level) + + NB. In the sequential world, (c) is only required so that the function closure has + an info table to point to, to keep the storage manager happy. + If (c) alone is true we could fake up an info table by choosing + one of a standard family of info tables, whose entry code just + bombs out. + + [NB In the parallel world (c) is needed regardless because + we enter functions with free vars via the closure.] + + If (c) is retained, then we'll sometimes generate an info table + (for storage mgr purposes) without slow-entry code. Then we need + to use an error label in the info table to substitute for the absent + slow entry code. +-} + +staticClosureRequired + :: Name + -> StgBinderInfo + -> LambdaFormInfo + -> Bool +staticClosureRequired binder bndr_info + (LFReEntrant top_level _ _ _) -- It's a function + = ASSERT( isTopLevel top_level ) + -- Assumption: it's a top-level, no-free-var binding + not (satCallsOnly bndr_info) + +staticClosureRequired binder other_binder_info other_lf_info = True +-} + +----------------------------------------------------------------------------- +-- Data types for closure information} +----------------------------------------------------------------------------- + + +{- Information about a closure, from the code generator's point of view. + +A ClosureInfo decribes the info pointer of a closure. It has +enough information + a) to construct the info table itself + b) to allocate a closure containing that info pointer (i.e. + it knows the info table label) + +We make a ClosureInfo for + - each let binding (both top level and not) + - each data constructor (for its shared static and + dynamic info tables) +-} + +data ClosureInfo + = ClosureInfo { + closureName :: !Name, -- The thing bound to this closure + closureLFInfo :: !LambdaFormInfo, -- NOTE: not an LFCon (see below) + closureSMRep :: !SMRep, -- representation used by storage mgr + closureSRT :: !C_SRT, -- What SRT applies to this closure + closureType :: !Type, -- Type of closure (ToDo: remove) + closureDescr :: !String -- closure description (for profiling) + } + + -- Constructor closures don't have a unique info table label (they use + -- the constructor's info table), and they don't have an SRT. + | ConInfo { + closureCon :: !DataCon, + closureSMRep :: !SMRep + } + +{- XXX temp imported from old ClosureInfo +-- C_SRT is what StgSyn.SRT gets translated to... +-- we add a label for the table, and expect only the 'offset/length' form + +data C_SRT = NoC_SRT + | C_SRT !CLabel !WordOff !StgHalfWord {-bitmap or escape-} + deriving (Eq) + +instance Outputable C_SRT where + ppr (NoC_SRT) = ptext SLIT("_no_srt_") + ppr (C_SRT label off bitmap) = parens (ppr label <> comma <> ppr off <> comma <> text (show bitmap)) +-} + +needsSRT :: C_SRT -> Bool +needsSRT NoC_SRT = False +needsSRT (C_SRT _ _ _) = True + + +-------------------------------------- +-- Building ClosureInfos +-------------------------------------- + +mkClosureInfo :: Bool -- Is static + -> Id + -> LambdaFormInfo + -> Int -> Int -- Total and pointer words + -> C_SRT + -> String -- String descriptor + -> ClosureInfo +mkClosureInfo is_static id lf_info tot_wds ptr_wds srt_info descr + = ClosureInfo { closureName = name, + closureLFInfo = lf_info, + closureSMRep = sm_rep, + closureSRT = srt_info, + closureType = idType id, + closureDescr = descr } + where + name = idName id + sm_rep = chooseSMRep is_static lf_info tot_wds ptr_wds + +mkConInfo :: Bool -- Is static + -> DataCon + -> Int -> Int -- Total and pointer words + -> ClosureInfo +mkConInfo is_static data_con tot_wds ptr_wds + = ConInfo { closureSMRep = sm_rep, + closureCon = data_con } + where + sm_rep = chooseSMRep is_static (mkConLFInfo data_con) tot_wds ptr_wds + + +-- We need a black-hole closure info to pass to @allocDynClosure@ when we +-- want to allocate the black hole on entry to a CAF. These are the only +-- ways to build an LFBlackHole, maintaining the invariant that it really +-- is a black hole and not something else. + +cafBlackHoleClosureInfo :: ClosureInfo -> ClosureInfo +cafBlackHoleClosureInfo (ClosureInfo { closureName = nm, + closureType = ty }) + = ClosureInfo { closureName = nm, + closureLFInfo = LFBlackHole mkCAFBlackHoleInfoTableLabel, + closureSMRep = BlackHoleRep, + closureSRT = NoC_SRT, + closureType = ty, + closureDescr = "" } +cafBlackHoleClosureInfo _ = panic "cafBlackHoleClosureInfo" + +seCafBlackHoleClosureInfo :: ClosureInfo -> ClosureInfo +seCafBlackHoleClosureInfo (ClosureInfo { closureName = nm, + closureType = ty }) + = ClosureInfo { closureName = nm, + closureLFInfo = LFBlackHole mkSECAFBlackHoleInfoTableLabel, + closureSMRep = BlackHoleRep, + closureSRT = NoC_SRT, + closureType = ty, + closureDescr = "" } +seCafBlackHoleClosureInfo _ = panic "seCafBlackHoleClosureInfo" + +-------------------------------------- +-- Extracting ClosureTypeInfo +-------------------------------------- + +closureTypeInfo :: ClosureInfo -> ClosureTypeInfo +closureTypeInfo cl_info + = case cl_info of + ConInfo { closureCon = con } + -> ConstrInfo (ptrs, nptrs) + (fromIntegral (dataConTagZ con)) + con_name + where + con_name = panic "closureTypeInfo" + -- Was: + -- cstr <- mkByteStringCLit $ dataConIdentity con + -- con_name = makeRelativeRefTo info_lbl cstr + + ClosureInfo { closureName = name, + closureLFInfo = LFReEntrant _ arity _ arg_descr, + closureSRT = srt } + -> FunInfo (ptrs, nptrs) + srt + (fromIntegral arity) + arg_descr + (CmmLabel (mkSlowEntryLabel name (clHasCafRefs cl_info))) + + ClosureInfo { closureLFInfo = LFThunk _ _ _ (SelectorThunk offset) _, + closureSRT = srt } + -> ThunkSelectorInfo (fromIntegral offset) srt + + ClosureInfo { closureLFInfo = LFThunk {}, + closureSRT = srt } + -> ThunkInfo (ptrs, nptrs) srt + + _ -> panic "unexpected lambda form in mkCmmInfo" + where +-- info_lbl = infoTableLabelFromCI cl_info + ptrs = fromIntegral $ closurePtrsSize cl_info + size = fromIntegral $ closureNonHdrSize cl_info + nptrs = size - ptrs + +-------------------------------------- +-- Functions about closure *sizes* +-------------------------------------- + +closureSize :: ClosureInfo -> WordOff +closureSize cl_info = hdr_size + closureNonHdrSize cl_info + where hdr_size | closureIsThunk cl_info = thunkHdrSize + | otherwise = fixedHdrSize + -- All thunks use thunkHdrSize, even if they are non-updatable. + -- this is because we don't have separate closure types for + -- updatable vs. non-updatable thunks, so the GC can't tell the + -- difference. If we ever have significant numbers of non- + -- updatable thunks, it might be worth fixing this. + +closureNonHdrSize :: ClosureInfo -> WordOff +closureNonHdrSize cl_info + = tot_wds + computeSlopSize tot_wds cl_info + where + tot_wds = closureGoodStuffSize cl_info + +closureGoodStuffSize :: ClosureInfo -> WordOff +closureGoodStuffSize cl_info + = let (ptrs, nonptrs) = sizes_from_SMRep (closureSMRep cl_info) + in ptrs + nonptrs + +closurePtrsSize :: ClosureInfo -> WordOff +closurePtrsSize cl_info + = let (ptrs, _) = sizes_from_SMRep (closureSMRep cl_info) + in ptrs + +-- not exported: +sizes_from_SMRep :: SMRep -> (WordOff,WordOff) +sizes_from_SMRep (GenericRep _ ptrs nonptrs _) = (ptrs, nonptrs) +sizes_from_SMRep BlackHoleRep = (0, 0) + +-- Computing slop size. WARNING: this looks dodgy --- it has deep +-- knowledge of what the storage manager does with the various +-- representations... +-- +-- Slop Requirements: every thunk gets an extra padding word in the +-- header, which takes the the updated value. + +slopSize :: ClosureInfo -> WordOff +slopSize cl_info = computeSlopSize payload_size cl_info + where payload_size = closureGoodStuffSize cl_info + +computeSlopSize :: WordOff -> ClosureInfo -> WordOff +computeSlopSize payload_size cl_info + = max 0 (minPayloadSize smrep updatable - payload_size) + where + smrep = closureSMRep cl_info + updatable = closureNeedsUpdSpace cl_info + +closureNeedsUpdSpace :: ClosureInfo -> Bool +-- We leave space for an update if either (a) the closure is updatable +-- or (b) it is a static thunk. This is because a static thunk needs +-- a static link field in a predictable place (after the slop), regardless +-- of whether it is updatable or not. +closureNeedsUpdSpace (ClosureInfo { closureLFInfo = + LFThunk TopLevel _ _ _ _ }) = True +closureNeedsUpdSpace cl_info = closureUpdReqd cl_info + +minPayloadSize :: SMRep -> Bool -> WordOff +minPayloadSize smrep updatable + = case smrep of + BlackHoleRep -> min_upd_size + GenericRep _ _ _ _ | updatable -> min_upd_size + GenericRep True _ _ _ -> 0 -- static + GenericRep False _ _ _ -> mIN_PAYLOAD_SIZE + -- ^^^^^___ dynamic + where + min_upd_size = + ASSERT(mIN_PAYLOAD_SIZE <= sIZEOF_StgSMPThunkHeader) + 0 -- check that we already have enough + -- room for mIN_SIZE_NonUpdHeapObject, + -- due to the extra header word in SMP + +-------------------------------------- +-- Other functions over ClosureInfo +-------------------------------------- + +blackHoleOnEntry :: ClosureInfo -> Bool +-- Static closures are never themselves black-holed. +-- Updatable ones will be overwritten with a CAFList cell, which points to a +-- black hole; +-- Single-entry ones have no fvs to plug, and we trust they don't form part +-- of a loop. + +blackHoleOnEntry ConInfo{} = False +blackHoleOnEntry (ClosureInfo { closureLFInfo = lf_info, closureSMRep = rep }) + | isStaticRep rep + = False -- Never black-hole a static closure + + | otherwise + = case lf_info of + LFReEntrant _ _ _ _ -> False + LFLetNoEscape -> False + LFThunk _ no_fvs updatable _ _ + -> if updatable + then not opt_OmitBlackHoling + else opt_DoTickyProfiling || not no_fvs + -- the former to catch double entry, + -- and the latter to plug space-leaks. KSW/SDM 1999-04. + + _other -> panic "blackHoleOnEntry" -- Should never happen + + +staticClosureNeedsLink :: ClosureInfo -> Bool +-- A static closure needs a link field to aid the GC when traversing +-- the static closure graph. But it only needs such a field if either +-- a) it has an SRT +-- b) it's a constructor with one or more pointer fields +-- In case (b), the constructor's fields themselves play the role +-- of the SRT. +staticClosureNeedsLink (ClosureInfo { closureSRT = srt }) + = needsSRT srt +staticClosureNeedsLink (ConInfo { closureSMRep = sm_rep, closureCon = con }) + = not (isNullaryRepDataCon con) && not_nocaf_constr + where + not_nocaf_constr = + case sm_rep of + GenericRep _ _ _ ConstrNoCaf -> False + _other -> True + +isStaticClosure :: ClosureInfo -> Bool +isStaticClosure cl_info = isStaticRep (closureSMRep cl_info) + +closureUpdReqd :: ClosureInfo -> Bool +closureUpdReqd ClosureInfo{ closureLFInfo = lf_info } = lfUpdatable lf_info +closureUpdReqd ConInfo{} = False + +lfUpdatable :: LambdaFormInfo -> Bool +lfUpdatable (LFThunk _ _ upd _ _) = upd +lfUpdatable (LFBlackHole _) = True + -- Black-hole closures are allocated to receive the results of an + -- alg case with a named default... so they need to be updated. +lfUpdatable _ = False + +closureIsThunk :: ClosureInfo -> Bool +closureIsThunk ClosureInfo{ closureLFInfo = lf_info } = isLFThunk lf_info +closureIsThunk ConInfo{} = False + +closureSingleEntry :: ClosureInfo -> Bool +closureSingleEntry (ClosureInfo { closureLFInfo = LFThunk _ _ upd _ _}) = not upd +closureSingleEntry _ = False + +closureReEntrant :: ClosureInfo -> Bool +closureReEntrant (ClosureInfo { closureLFInfo = LFReEntrant _ _ _ _ }) = True +closureReEntrant _ = False + +isConstrClosure_maybe :: ClosureInfo -> Maybe DataCon +isConstrClosure_maybe (ConInfo { closureCon = data_con }) = Just data_con +isConstrClosure_maybe _ = Nothing + +closureFunInfo :: ClosureInfo -> Maybe (Int, ArgDescr) +closureFunInfo (ClosureInfo { closureLFInfo = lf_info }) = lfFunInfo lf_info +closureFunInfo _ = Nothing + +lfFunInfo :: LambdaFormInfo -> Maybe (Int, ArgDescr) +lfFunInfo (LFReEntrant _ arity _ arg_desc) = Just (arity, arg_desc) +lfFunInfo _ = Nothing + +funTag :: ClosureInfo -> DynTag +funTag (ClosureInfo { closureLFInfo = lf_info }) = lfDynTag lf_info +funTag (ConInfo {}) = panic "funTag" + +isToplevClosure :: ClosureInfo -> Bool +isToplevClosure (ClosureInfo { closureLFInfo = lf_info }) + = case lf_info of + LFReEntrant TopLevel _ _ _ -> True + LFThunk TopLevel _ _ _ _ -> True + _other -> False +isToplevClosure _ = False + +-------------------------------------- +-- Label generation +-------------------------------------- + +infoTableLabelFromCI :: ClosureInfo -> CLabel +infoTableLabelFromCI cl@(ClosureInfo { closureName = name, + closureLFInfo = lf_info }) + = case lf_info of + LFBlackHole info -> info + + LFThunk _ _ upd_flag (SelectorThunk offset) _ -> + mkSelectorInfoLabel upd_flag offset + + LFThunk _ _ upd_flag (ApThunk arity) _ -> + mkApInfoTableLabel upd_flag arity + + LFThunk{} -> mkLocalInfoTableLabel name $ clHasCafRefs cl + + LFReEntrant _ _ _ _ -> mkLocalInfoTableLabel name $ clHasCafRefs cl + + _other -> panic "infoTableLabelFromCI" + +infoTableLabelFromCI cl@(ConInfo { closureCon = con, closureSMRep = rep }) + | isStaticRep rep = mkStaticInfoTableLabel name $ clHasCafRefs cl + | otherwise = mkConInfoTableLabel name $ clHasCafRefs cl + where + name = dataConName con + +-- ClosureInfo for a closure (as opposed to a constructor) is always local +closureLabelFromCI :: ClosureInfo -> CLabel +closureLabelFromCI cl@(ClosureInfo { closureName = nm }) = + mkLocalClosureLabel nm $ clHasCafRefs cl +closureLabelFromCI _ = panic "closureLabelFromCI" + +thunkEntryLabel :: Name -> CafInfo -> StandardFormInfo -> Bool -> CLabel +-- thunkEntryLabel is a local help function, not exported. It's used from both +-- entryLabelFromCI and getCallMethod. +thunkEntryLabel _thunk_id _ (ApThunk arity) upd_flag + = enterApLabel upd_flag arity +thunkEntryLabel _thunk_id _ (SelectorThunk offset) upd_flag + = enterSelectorLabel upd_flag offset +thunkEntryLabel thunk_id c _ _ + = enterIdLabel thunk_id c + +enterApLabel :: Bool -> Arity -> CLabel +enterApLabel is_updatable arity + | tablesNextToCode = mkApInfoTableLabel is_updatable arity + | otherwise = mkApEntryLabel is_updatable arity + +enterSelectorLabel :: Bool -> WordOff -> CLabel +enterSelectorLabel upd_flag offset + | tablesNextToCode = mkSelectorInfoLabel upd_flag offset + | otherwise = mkSelectorEntryLabel upd_flag offset + +enterIdLabel :: Name -> CafInfo -> CLabel +enterIdLabel id c + | tablesNextToCode = mkInfoTableLabel id c + | otherwise = mkEntryLabel id c + +enterLocalIdLabel :: Name -> CafInfo -> CLabel +enterLocalIdLabel id c + | tablesNextToCode = mkLocalInfoTableLabel id c + | otherwise = mkLocalEntryLabel id c + + +-------------------------------------- +-- Profiling +-------------------------------------- + +-- Profiling requires two pieces of information to be determined for +-- each closure's info table --- description and type. + +-- The description is stored directly in the @CClosureInfoTable@ when the +-- info table is built. + +-- The type is determined from the type information stored with the @Id@ +-- in the closure info using @closureTypeDescr@. + +closureValDescr, closureTypeDescr :: ClosureInfo -> String +closureValDescr (ClosureInfo {closureDescr = descr}) + = descr +closureValDescr (ConInfo {closureCon = con}) + = occNameString (getOccName con) + +closureTypeDescr (ClosureInfo { closureType = ty }) + = getTyDescription ty +closureTypeDescr (ConInfo { closureCon = data_con }) + = occNameString (getOccName (dataConTyCon data_con)) + +getTyDescription :: Type -> String +getTyDescription ty + = case (tcSplitSigmaTy ty) of { (_, _, tau_ty) -> + case tau_ty of + TyVarTy _ -> "*" + AppTy fun _ -> getTyDescription fun + FunTy _ res -> '-' : '>' : fun_result res + TyConApp tycon _ -> getOccString tycon + PredTy sty -> getPredTyDescription sty + ForAllTy _ ty -> getTyDescription ty + } + where + fun_result (FunTy _ res) = '>' : fun_result res + fun_result other = getTyDescription other + +getPredTyDescription :: PredType -> String +getPredTyDescription (ClassP cl _) = getOccString cl +getPredTyDescription (IParam ip _) = getOccString (ipNameName ip) +getPredTyDescription (EqPred ty1 _ty2) = getTyDescription ty1 -- Urk? + + +-------------------------------------- +-- SRTs/CAFs +-------------------------------------- + +-- This is horrible, but we need to know whether a closure may have CAFs. +clHasCafRefs :: ClosureInfo -> CafInfo +clHasCafRefs (ClosureInfo {closureSRT = srt}) = + case srt of NoC_SRT -> NoCafRefs + _ -> MayHaveCafRefs +clHasCafRefs (ConInfo {}) = NoCafRefs |