diff options
Diffstat (limited to 'compiler/codeGen/ClosureInfo.lhs')
| -rw-r--r-- | compiler/codeGen/ClosureInfo.lhs | 51 |
1 files changed, 32 insertions, 19 deletions
diff --git a/compiler/codeGen/ClosureInfo.lhs b/compiler/codeGen/ClosureInfo.lhs index c55a9f936f..de4318afb0 100644 --- a/compiler/codeGen/ClosureInfo.lhs +++ b/compiler/codeGen/ClosureInfo.lhs @@ -33,7 +33,7 @@ module ClosureInfo ( isLFThunk, closureUpdReqd, closureNeedsUpdSpace, closureIsThunk, closureSingleEntry, closureReEntrant, isConstrClosure_maybe, - closureFunInfo, isStandardFormThunk, isKnownFun, + closureFunInfo, isKnownFun, funTag, funTagLFInfo, tagForArity, clHasCafRefs, enterIdLabel, enterLocalIdLabel, enterReturnPtLabel, @@ -118,7 +118,7 @@ data ClosureInfo 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) + closureType :: !Type, -- Type of closure (ToDo: remove) closureDescr :: !String, -- closure description (for profiling) closureInfLcl :: Bool -- can the info pointer be a local symbol? } @@ -707,35 +707,48 @@ getCallMethod _ name _ (LFLetNoEscape arity) n_args | n_args == arity = DirectEntry (enterReturnPtLabel (nameUnique name)) arity | otherwise = pprPanic "let-no-escape: " (ppr name <+> ppr arity) -blackHoleOnEntry :: DynFlags -> ClosureInfo -> Bool + +-- Eager blackholing is normally disabled, but can be turned on with +-- -feager-blackholing. When it is on, we replace the info pointer of +-- the thunk with stg_EAGER_BLACKHOLE_info on entry. + +-- If we wanted to do eager blackholing with slop filling, +-- we'd need to do it at the *end* of a basic block, otherwise +-- we overwrite the free variables in the thunk that we still +-- need. We have a patch for this from Andy Cheadle, but not +-- incorporated yet. --SDM [6/2004] +-- +-- +-- Previously, eager blackholing was enabled when ticky-ticky +-- was on. But it didn't work, and it wasn't strictly necessary +-- to bring back minimal ticky-ticky, so now EAGER_BLACKHOLING +-- is unconditionally disabled. -- krc 1/2007 + -- 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 :: DynFlags -> ClosureInfo -> Bool blackHoleOnEntry _ ConInfo{} = False -blackHoleOnEntry dflags (ClosureInfo { closureLFInfo = lf_info, closureSMRep = rep }) - | isStaticRep rep +blackHoleOnEntry dflags cl_info + | isStaticRep (closureSMRep cl_info) = False -- Never black-hole a static closure | otherwise - = case lf_info of + = case closureLFInfo cl_info of LFReEntrant _ _ _ _ -> False - LFLetNoEscape _ -> False + LFLetNoEscape _ -> False LFThunk _ no_fvs updatable _ _ - -> if updatable - then not opt_OmitBlackHoling - else doingTickyProfiling dflags || not no_fvs + | eager_blackholing -> doingTickyProfiling dflags || not no_fvs -- the former to catch double entry, -- and the latter to plug space-leaks. KSW/SDM 1999-04. + | otherwise -> False - _ -> panic "blackHoleOnEntry" -- Should never happen + where eager_blackholing = not opt_SccProfilingOn + && dopt Opt_EagerBlackHoling dflags + -- Profiling needs slop filling (to support + -- LDV profiling), so currently eager + -- blackholing doesn't work with profiling. -isStandardFormThunk :: LambdaFormInfo -> Bool -isStandardFormThunk (LFThunk _ _ _ (SelectorThunk _) _) = True -isStandardFormThunk (LFThunk _ _ _ (ApThunk _) _) = True -isStandardFormThunk _ = False + _other -> panic "blackHoleOnEntry" -- Should never happen isKnownFun :: LambdaFormInfo -> Bool isKnownFun (LFReEntrant _ _ _ _) = True |