% % (c) The University of Glasgow 2006 % (c) The Univserity of Glasgow 1992-2004 % Data structures which describe closures, and operations over those data structures Nothing monadic in here Much of the rationale for these things is in the ``details'' part of the STG paper. \begin{code} {-# OPTIONS -w #-} -- The above warning supression flag is a temporary kludge. -- While working on this module you are encouraged to remove it and fix -- any warnings in the module. See -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings -- for details module ClosureInfo ( ClosureInfo(..), LambdaFormInfo(..), -- would be abstract but StandardFormInfo(..), -- mkCmmInfo looks inside SMRep, ArgDescr(..), Liveness(..), C_SRT(..), needsSRT, mkLFThunk, mkLFReEntrant, mkConLFInfo, mkSelectorLFInfo, mkApLFInfo, mkLFImported, mkLFArgument, mkLFLetNoEscape, mkClosureInfo, mkConInfo, maybeIsLFCon, closureSize, closureNonHdrSize, closureGoodStuffSize, closurePtrsSize, slopSize, closureName, infoTableLabelFromCI, closureLabelFromCI, closureSRT, closureLFInfo, isLFThunk,closureSMRep, closureUpdReqd, closureNeedsUpdSpace, closureIsThunk, closureSingleEntry, closureReEntrant, isConstrClosure_maybe, closureFunInfo, isStandardFormThunk, isKnownFun, funTag, funTagLFInfo, tagForArity, enterIdLabel, enterLocalIdLabel, enterReturnPtLabel, nodeMustPointToIt, CallMethod(..), getCallMethod, blackHoleOnEntry, staticClosureRequired, getClosureType, isToplevClosure, closureValDescr, closureTypeDescr, -- profiling isStaticClosure, cafBlackHoleClosureInfo, seCafBlackHoleClosureInfo, staticClosureNeedsLink, ) where #include "../includes/MachDeps.h" #include "HsVersions.h" --import CgUtils import StgSyn import SMRep import CLabel import Packages import PackageConfig import StaticFlags import Id import DataCon import Name import OccName import Type import TypeRep import TcType import TyCon import BasicTypes import FastString import Outputable import Constants \end{code} %************************************************************************ %* * \subsection[ClosureInfo-datatypes]{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) \begin{code} 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 } -- 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) needsSRT :: C_SRT -> Bool needsSRT NoC_SRT = False needsSRT (C_SRT _ _ _) = True 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)) \end{code} %************************************************************************ %* * \subsubsection[LambdaFormInfo-datatype]{@LambdaFormInfo@: source-derivable info} %* * %************************************************************************ 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. Note that a closure is usually bound to an identifier, so a ClosureInfo contains a LambdaFormInfo. \begin{code} 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 reall be in ClosureInfo) | LFCon -- A saturated constructor application DataCon -- The constructor | 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 | 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 | LFLetNoEscape -- See LetNoEscape module for precise description of -- these "lets". !Int -- arity; | 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 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 ------------------------- -- 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 \end{code} %************************************************************************ %* * \subsection[ClosureInfo-construction]{Functions which build LFInfos} %* * %************************************************************************ \begin{code} 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 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 \end{code} @mkConLFInfo@ is similar, for constructors. \begin{code} mkConLFInfo :: DataCon -> LambdaFormInfo mkConLFInfo con = LFCon con maybeIsLFCon :: LambdaFormInfo -> Maybe DataCon maybeIsLFCon (LFCon con) = Just con maybeIsLFCon _ = Nothing mkSelectorLFInfo id offset updatable = LFThunk NotTopLevel False updatable (SelectorThunk offset) (might_be_a_function (idType id)) mkApLFInfo id upd_flag arity = LFThunk NotTopLevel (arity == 0) (isUpdatable upd_flag) (ApThunk arity) (might_be_a_function (idType id)) \end{code} Miscellaneous LF-infos. \begin{code} mkLFArgument id = LFUnknown (might_be_a_function (idType id)) mkLFLetNoEscape = LFLetNoEscape mkLFImported :: Id -> LambdaFormInfo mkLFImported id = case idArity id of n | n > 0 -> LFReEntrant TopLevel n True (panic "arg_descr") -- n > 0 other -> mkLFArgument id -- Not sure of exact arity \end{code} \begin{code} 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 \end{code} %************************************************************************ %* * Building ClosureInfos %* * %************************************************************************ \begin{code} 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 \end{code} %************************************************************************ %* * \subsection[ClosureInfo-sizes]{Functions about closure {\em sizes}} %* * %************************************************************************ \begin{code} 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) \end{code} 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. \begin{code} 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 -- 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 \end{code} %************************************************************************ %* * \subsection[SMreps]{Choosing SM reps} %* * %************************************************************************ \begin{code} 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 con | is_static && ptr_wds == 0 -> ConstrNoCaf | otherwise -> Constr LFReEntrant _ _ _ _ -> Fun LFThunk _ _ _ (SelectorThunk _) _ -> ThunkSelector LFThunk _ _ _ _ _ -> Thunk _ -> panic "getClosureType" \end{code} %************************************************************************ %* * \subsection[ClosureInfo-4-questions]{Four major questions about @ClosureInfo@} %* * %************************************************************************ Be sure to see the stg-details notes about these... \begin{code} 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 _ no_fvs updatable some_standard_form_thunk _) = True -- Node must point to any standard-form thunk nodeMustPointToIt (LFUnknown _) = True nodeMustPointToIt (LFBlackHole _) = True -- BH entry may require Node to point nodeMustPointToIt (LFLetNoEscape _) = False \end{code} 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. \begin{tabular}{lllll} Closure Characteristics & Parallel & Node Req'd & Argument Passing & Enter Via \\ Unknown & no & yes & stack & node \\ Known fun ($\ge$ 1 arg), no fvs & no & no & registers & fast entry (enough args) \\ \ & \ & \ & \ & slow entry (otherwise) \\ Known fun ($\ge$ 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 ($\ge$ 1 arg), no fvs & yes & no & registers & fast entry (enough args) \\ \ & \ & \ & \ & slow entry (otherwise) \\ Known fun ($\ge$ 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. \begin{code} data CallMethod = EnterIt -- no args, not a function | JumpToIt CLabel -- no args, not a function, but we -- know what its entry code is | ReturnIt -- it's a function, but we have -- zero args to apply to it, so just -- return it. | ReturnCon DataCon -- It's a data constructor, 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 -> 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 (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) arity getCallMethod name (LFCon con) n_args = ASSERT( n_args == 0 ) ReturnCon con getCallMethod name (LFThunk _ _ updatable std_form_info is_fun) n_args | is_fun -- *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 ) JumpToIt (thunkEntryLabel name std_form_info updatable) 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 0) n_args = JumpToIt (enterReturnPtLabel (nameUnique name)) getCallMethod name (LFLetNoEscape arity) n_args | n_args == arity = DirectEntry (enterReturnPtLabel (nameUnique name)) arity | otherwise = pprPanic "let-no-escape: " (ppr name <+> ppr arity) 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 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 \end{code} ----------------------------------------------------------------------------- SRT-related stuff \begin{code} 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 \end{code} 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. \begin{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 \end{code} %************************************************************************ %* * \subsection[ClosureInfo-misc-funs]{Misc functions about @ClosureInfo@, etc.} %* * %************************************************************************ \begin{code} 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 other_closure = False closureReEntrant :: ClosureInfo -> Bool closureReEntrant (ClosureInfo { closureLFInfo = LFReEntrant _ _ _ _ }) = True closureReEntrant other_closure = 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 -> Int funTag (ClosureInfo { closureLFInfo = lf_info }) = funTagLFInfo lf_info funTag _ = 0 -- maybe this should do constructor tags too? funTagLFInfo :: LambdaFormInfo -> Int funTagLFInfo lf -- A function is tagged with its arity | Just (arity,_) <- lfFunInfo lf, Just tag <- tagForArity arity = tag -- other closures (and unknown ones) are not tagged | otherwise = 0 tagForArity :: Int -> Maybe Int tagForArity i | i <= mAX_PTR_TAG = Just i | otherwise = Nothing \end{code} \begin{code} isToplevClosure :: ClosureInfo -> Bool isToplevClosure (ClosureInfo { closureLFInfo = lf_info }) = case lf_info of LFReEntrant TopLevel _ _ _ -> True LFThunk TopLevel _ _ _ _ -> True other -> False isToplevClosure _ = False \end{code} Label generation. \begin{code} infoTableLabelFromCI :: ClosureInfo -> CLabel infoTableLabelFromCI (ClosureInfo { closureName = name, closureLFInfo = lf_info, closureSMRep = rep }) = 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 LFReEntrant _ _ _ _ -> mkLocalInfoTableLabel name other -> panic "infoTableLabelFromCI" infoTableLabelFromCI (ConInfo { closureCon = con, closureSMRep = rep }) | isStaticRep rep = mkStaticInfoTableLabel name | otherwise = mkConInfoTableLabel name where name = dataConName con -- ClosureInfo for a closure (as opposed to a constructor) is always local closureLabelFromCI (ClosureInfo { closureName = nm }) = mkLocalClosureLabel nm closureLabelFromCI _ = panic "closureLabelFromCI" -- thunkEntryLabel is a local help function, not exported. It's used from both -- entryLabelFromCI and getCallMethod. thunkEntryLabel thunk_id (ApThunk arity) is_updatable = enterApLabel is_updatable arity thunkEntryLabel thunk_id (SelectorThunk offset) upd_flag = enterSelectorLabel upd_flag offset thunkEntryLabel thunk_id _ is_updatable = enterIdLabel thunk_id enterApLabel is_updatable arity | tablesNextToCode = mkApInfoTableLabel is_updatable arity | otherwise = mkApEntryLabel is_updatable arity enterSelectorLabel upd_flag offset | tablesNextToCode = mkSelectorInfoLabel upd_flag offset | otherwise = mkSelectorEntryLabel upd_flag offset enterIdLabel id | tablesNextToCode = mkInfoTableLabel id | otherwise = mkEntryLabel id enterLocalIdLabel id | tablesNextToCode = mkLocalInfoTableLabel id | otherwise = mkLocalEntryLabel id enterReturnPtLabel name | tablesNextToCode = mkReturnInfoLabel name | otherwise = mkReturnPtLabel name \end{code} 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. \begin{code} 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 { closureName = nm, closureType = ty }) = ClosureInfo { closureName = nm, closureLFInfo = LFBlackHole mkSECAFBlackHoleInfoTableLabel, closureSMRep = BlackHoleRep, closureSRT = NoC_SRT, closureType = ty, closureDescr = "" } seCafBlackHoleClosureInfo _ = panic "seCafBlackHoleClosureInfo" \end{code} %************************************************************************ %* * \subsection[ClosureInfo-Profiling-funs]{Misc functions about for profiling info.} %* * %************************************************************************ 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@. \begin{code} 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 NoteTy (FTVNote _) ty -> getTyDescription ty PredTy sty -> getPredTyDescription sty ForAllTy _ ty -> getTyDescription ty } where fun_result (FunTy _ res) = '>' : fun_result res fun_result other = getTyDescription other getPredTyDescription (ClassP cl tys) = getOccString cl getPredTyDescription (IParam ip ty) = getOccString (ipNameName ip) \end{code}