diff options
Diffstat (limited to 'compiler/GHC/StgToCmm/Closure.hs')
| -rw-r--r-- | compiler/GHC/StgToCmm/Closure.hs | 104 |
1 files changed, 22 insertions, 82 deletions
diff --git a/compiler/GHC/StgToCmm/Closure.hs b/compiler/GHC/StgToCmm/Closure.hs index 2c1176c197..fc4b79d71f 100644 --- a/compiler/GHC/StgToCmm/Closure.hs +++ b/compiler/GHC/StgToCmm/Closure.hs @@ -70,6 +70,7 @@ import GHC.Stg.Syntax import GHC.Runtime.Heap.Layout import GHC.Cmm import GHC.Cmm.Ppr.Expr() -- For Outputable instances +import GHC.StgToCmm.Types import GHC.Types.CostCentre import GHC.Cmm.BlockId @@ -188,76 +189,6 @@ addArgReps = map (\arg -> let arg' = fromNonVoid arg argPrimRep :: StgArg -> PrimRep argPrimRep arg = typePrimRep1 (stgArgType arg) - ------------------------------------------------------------------------------ --- 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 - !RepArity -- 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, needs evaluation - - | LFLetNoEscape -- See LetNoEscape module for precise description - - -------------------------- --- StandardFormInfo tells whether this thunk has one of --- a small number of standard forms - -data StandardFormInfo - = NonStandardThunk - -- The usual case: not 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. - RepArity -- Arity, n - - ------------------------------------------------------ -- Building LambdaFormInfo ------------------------------------------------------ @@ -325,18 +256,27 @@ mkApLFInfo id upd_flag arity ------------- 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 +mkLFImported id = + -- See Note [Conveying CAF-info and LFInfo between modules] in + -- GHC.StgToCmm.Types + case idLFInfo_maybe id of + Just lf_info -> + -- Use the LambdaFormInfo from the interface + lf_info + Nothing + -- Interface doesn't have a LambdaFormInfo, make a conservative one from + -- the type. + | 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 ArgUnknown + + | otherwise + -> mkLFArgument id -- Not sure of exact arity where arity = idFunRepArity id |