%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
+%
+% $Id: CgClosure.lhs,v 1.72 2005/05/18 12:06:51 simonmar Exp $
%
\section[CgClosure]{Code generation for closures}
@CgCon@, which deals with constructors.
\begin{code}
-#include "HsVersions.h"
+module CgClosure ( cgTopRhsClosure,
+ cgStdRhsClosure,
+ cgRhsClosure,
+ emitBlackHoleCode,
+ ) where
-module CgClosure ( cgTopRhsClosure, cgRhsClosure ) where
+#include "HsVersions.h"
-IMP_Ubiq(){-uitous-}
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 201
-IMPORT_DELOOPER(CgLoop2) ( cgExpr )
-#else
import {-# SOURCE #-} CgExpr ( cgExpr )
-#endif
import CgMonad
-import AbsCSyn
-import StgSyn
-
-import AbsCUtils ( mkAbstractCs, getAmodeRep )
-import CgBindery ( getCAddrMode, getArgAmodes,
- getCAddrModeAndInfo, bindNewToNode,
- bindNewToAStack, bindNewToBStack,
- bindNewToReg, bindArgsToRegs,
- stableAmodeIdInfo, heapIdInfo, CgIdInfo
- )
-import Constants ( spARelToInt, spBRelToInt )
-import CgUpdate ( pushUpdateFrame )
-import CgHeapery ( allocDynClosure, heapCheck
- , heapCheckOnly, fetchAndReschedule, yield -- HWL
- )
-import CgRetConv ( ctrlReturnConvAlg, dataReturnConvAlg,
- CtrlReturnConvention(..), DataReturnConvention(..)
- )
-import CgStackery ( getFinalStackHW, mkVirtStkOffsets,
- adjustRealSps
- )
-import CgUsages ( getVirtSps, setRealAndVirtualSps,
- getSpARelOffset, getSpBRelOffset,
- getHpRelOffset
- )
-import CLabel ( mkClosureLabel, mkConUpdCodePtrVecLabel, mkFastEntryLabel,
- mkStdUpdCodePtrVecLabel, mkStdUpdVecTblLabel,
- mkErrorStdEntryLabel, mkRednCountsLabel
- )
+import CgBindery
+import CgHeapery
+import CgStackery ( mkVirtStkOffsets, pushUpdateFrame, getVirtSp,
+ setRealAndVirtualSp )
+import CgProf ( chooseDynCostCentres, ldvEnter, enterCostCentre,
+ costCentreFrom )
+import CgTicky
+import CgParallel ( granYield, granFetchAndReschedule )
+import CgInfoTbls ( emitClosureCodeAndInfoTable, getSRTInfo )
+import CgCallConv ( assignCallRegs, mkArgDescr )
+import CgUtils ( emitDataLits, addIdReps, cmmRegOffW,
+ emitRtsCallWithVols )
import ClosureInfo -- lots and lots of stuff
-import CmdLineOpts ( opt_ForConcurrent, opt_GranMacros )
-import CostCentre ( useCurrentCostCentre, currentOrSubsumedCosts,
- noCostCentreAttached, costsAreSubsumed,
- isCafCC, isDictCC, overheadCostCentre, showCostCentre,
- CostCentre
- )
-import HeapOffs ( SYN_IE(VirtualHeapOffset) )
-import Id ( idType, idPrimRep,
- showId, getIdStrictness, dataConTag,
- emptyIdSet,
- GenId{-instance Outputable-}, SYN_IE(Id)
- )
+import SMRep ( CgRep, cgRepSizeW, argMachRep, fixedHdrSize, WordOff,
+ idCgRep )
+import MachOp ( MachHint(..) )
+import Cmm
+import CmmUtils ( CmmStmts, mkStmts, oneStmt, plusStmts, noStmts,
+ mkLblExpr )
+import CLabel
+import StgSyn
+import StaticFlags ( opt_DoTickyProfiling )
+import CostCentre
+import Id ( Id, idName, idType )
+import Name ( Name, isExternalName )
+import Module ( Module, pprModule )
import ListSetOps ( minusList )
-import Maybes ( maybeToBool )
-import Outputable ( Outputable(..){-instances-}, PprStyle(..) )
-import PprType ( GenType{-instance Outputable-}, TyCon{-ditto-} )
-import Pretty ( Doc, hcat, char, ptext, hsep, text )
-import PrimRep ( isFollowableRep, PrimRep(..) )
-import TyCon ( isPrimTyCon, tyConDataCons )
-import Type ( showTypeCategory )
-import Util ( isIn, panic, pprPanic, assertPanic, pprTrace{-ToDo:rm-} )
-
-getWrapperArgTypeCategories = panic "CgClosure.getWrapperArgTypeCategories (ToDo)"
+import Util ( isIn, mapAccumL, zipWithEqual )
+import BasicTypes ( TopLevelFlag(..) )
+import Constants ( oFFSET_StgInd_indirectee, wORD_SIZE )
+import Outputable
+import FastString
\end{code}
%********************************************************
\begin{code}
cgTopRhsClosure :: Id
- -> CostCentre -- Optional cost centre annotation
+ -> CostCentreStack -- Optional cost centre annotation
-> StgBinderInfo
+ -> SRT
+ -> UpdateFlag
-> [Id] -- Args
-> StgExpr
- -> LambdaFormInfo
-> FCode (Id, CgIdInfo)
-cgTopRhsClosure name cc binder_info args body lf_info
- = -- LAY OUT THE OBJECT
- let
- closure_info = layOutStaticNoFVClosure name lf_info
- in
-
- -- GENERATE THE INFO TABLE (IF NECESSARY)
- forkClosureBody (closureCodeBody binder_info closure_info
- cc args body)
- `thenC`
-
- -- BUILD VAP INFO TABLES IF NECESSARY
- -- Don't build Vap info tables etc for
- -- a function whose result is an unboxed type,
- -- because we can never have thunks with such a type.
- (if closureReturnsUnboxedType closure_info then
- nopC
- else
- let
- bind_the_fun = addBindC name cg_id_info -- It's global!
- in
- cgVapInfoTables True {- Top level -} bind_the_fun binder_info name args lf_info
- ) `thenC`
-
- -- BUILD THE OBJECT (IF NECESSARY)
- (if staticClosureRequired name binder_info lf_info
- then
- let
- cost_centre = mkCCostCentre cc
- in
- absC (CStaticClosure
- closure_label -- Labelled with the name on lhs of defn
- closure_info
- cost_centre
- []) -- No fields
- else
- nopC
- ) `thenC`
-
- returnFC (name, cg_id_info)
- where
- closure_label = mkClosureLabel name
- cg_id_info = stableAmodeIdInfo name (CLbl closure_label PtrRep) lf_info
+cgTopRhsClosure id ccs binder_info srt upd_flag args body = do
+ { -- LAY OUT THE OBJECT
+ let name = idName id
+ ; lf_info <- mkClosureLFInfo id TopLevel [] upd_flag args
+ ; srt_info <- getSRTInfo name srt
+ ; mod_name <- moduleName
+ ; let descr = closureDescription mod_name name
+ closure_info = mkClosureInfo True id lf_info 0 0 srt_info descr
+ closure_label = mkLocalClosureLabel name
+ cg_id_info = stableIdInfo id (mkLblExpr closure_label) lf_info
+ closure_rep = mkStaticClosureFields closure_info ccs True []
+
+ -- BUILD THE OBJECT, AND GENERATE INFO TABLE (IF NECESSARY)
+ ; emitDataLits closure_label closure_rep
+ ; forkClosureBody (closureCodeBody binder_info closure_info
+ ccs args body)
+
+ ; returnFC (id, cg_id_info) }
\end{code}
%********************************************************
For closures with free vars, allocate in heap.
-===================== OLD PROBABLY OUT OF DATE COMMENTS =============
-
--- Closures which (a) have no fvs and (b) have some args (i.e.
--- combinator functions), are allocated statically, just as if they
--- were top-level closures. We can't get a space leak that way
--- (because they are HNFs) and it saves allocation.
-
--- Lexical Scoping: Problem
--- These top level function closures will be inherited, possibly
--- to a different cost centre scope set before entering.
-
--- Evaluation Scoping: ok as already in HNF
+\begin{code}
+cgStdRhsClosure
+ :: Id
+ -> CostCentreStack -- Optional cost centre annotation
+ -> StgBinderInfo
+ -> [Id] -- Free vars
+ -> [Id] -- Args
+ -> StgExpr
+ -> LambdaFormInfo
+ -> [StgArg] -- payload
+ -> FCode (Id, CgIdInfo)
+
+cgStdRhsClosure bndr cc bndr_info fvs args body lf_info payload
+ = do -- AHA! A STANDARD-FORM THUNK
+ { -- LAY OUT THE OBJECT
+ amodes <- getArgAmodes payload
+ ; mod_name <- moduleName
+ ; let (tot_wds, ptr_wds, amodes_w_offsets)
+ = mkVirtHeapOffsets (isLFThunk lf_info) amodes
+
+ descr = closureDescription mod_name (idName bndr)
+ closure_info = mkClosureInfo False -- Not static
+ bndr lf_info tot_wds ptr_wds
+ NoC_SRT -- No SRT for a std-form closure
+ descr
+
+ ; (use_cc, blame_cc) <- chooseDynCostCentres cc args body
--- Should rely on floating mechanism to achieve this floating to top level.
--- As let floating will avoid floating which breaks cost centre attribution
--- everything will be OK.
+ -- BUILD THE OBJECT
+ ; heap_offset <- allocDynClosure closure_info use_cc blame_cc amodes_w_offsets
--- Disabled: because it breaks lexical-scoped cost centre semantics.
--- cgRhsClosure binder cc bi [] upd_flag args@(_:_) body
--- = cgTopRhsClosure binder cc bi upd_flag args body
+ -- RETURN
+ ; returnFC (bndr, heapIdInfo bndr heap_offset lf_info) }
+\end{code}
-===================== END OF OLD PROBABLY OUT OF DATE COMMENTS =============
+Here's the general case.
\begin{code}
cgRhsClosure :: Id
- -> CostCentre -- Optional cost centre annotation
+ -> CostCentreStack -- Optional cost centre annotation
-> StgBinderInfo
- -> [Id] -- Free vars
- -> [Id] -- Args
+ -> SRT
+ -> [Id] -- Free vars
+ -> UpdateFlag
+ -> [Id] -- Args
-> StgExpr
- -> LambdaFormInfo
-> FCode (Id, CgIdInfo)
-cgRhsClosure binder cc binder_info fvs args body lf_info
- | maybeToBool maybe_std_thunk -- AHA! A STANDARD-FORM THUNK
- -- ToDo: check non-primitiveness (ASSERT)
- = (
- -- LAY OUT THE OBJECT
- getArgAmodes std_thunk_payload `thenFC` \ amodes ->
- let
- (closure_info, amodes_w_offsets)
- = layOutDynClosure binder getAmodeRep amodes lf_info
-
- (use_cc, blame_cc) = chooseDynCostCentres cc args fvs body
- in
- -- BUILD THE OBJECT
- allocDynClosure closure_info use_cc blame_cc amodes_w_offsets
- )
- `thenFC` \ heap_offset ->
-
- -- RETURN
- returnFC (binder, heapIdInfo binder heap_offset lf_info)
-
- where
- maybe_std_thunk = getStandardFormThunkInfo lf_info
- Just std_thunk_payload = maybe_std_thunk
-\end{code}
-
-Here's the general case.
-\begin{code}
-cgRhsClosure binder cc binder_info fvs args body lf_info
- = (
- -- LAY OUT THE OBJECT
- --
+cgRhsClosure bndr cc bndr_info srt fvs upd_flag args body = do
+ { -- LAY OUT THE OBJECT
-- If the binder is itself a free variable, then don't store
-- it in the closure. Instead, just bind it to Node on entry.
-- NB we can be sure that Node will point to it, because we
-- havn't told mkClosureLFInfo about this; so if the binder
- -- *was* a free var of its RHS, mkClosureLFInfo thinks it *is*
+ -- _was_ a free var of its RHS, mkClosureLFInfo thinks it *is*
-- stored in the closure itself, so it will make sure that
-- Node points to it...
let
- is_elem = isIn "cgRhsClosure"
-
- binder_is_a_fv = binder `is_elem` fvs
- reduced_fvs = if binder_is_a_fv
- then fvs `minusList` [binder]
- else fvs
- in
- mapFCs getCAddrModeAndInfo reduced_fvs `thenFC` \ amodes_and_info ->
- let
- fvs_w_amodes_and_info = reduced_fvs `zip` amodes_and_info
-
- closure_info :: ClosureInfo
- bind_details :: [((Id, (CAddrMode, LambdaFormInfo)), VirtualHeapOffset)]
-
- (closure_info, bind_details)
- = layOutDynClosure binder get_kind fvs_w_amodes_and_info lf_info
+ name = idName bndr
+ is_elem = isIn "cgRhsClosure"
+ bndr_is_a_fv = bndr `is_elem` fvs
+ reduced_fvs | bndr_is_a_fv = fvs `minusList` [bndr]
+ | otherwise = fvs
+
+ ; lf_info <- mkClosureLFInfo bndr NotTopLevel fvs upd_flag args
+ ; fv_infos <- mapFCs getCgIdInfo reduced_fvs
+ ; srt_info <- getSRTInfo name srt
+ ; mod_name <- moduleName
+ ; let bind_details :: [(CgIdInfo, VirtualHpOffset)]
+ (tot_wds, ptr_wds, bind_details)
+ = mkVirtHeapOffsets (isLFThunk lf_info) (map add_rep fv_infos)
+
+ add_rep info = (cgIdInfoArgRep info, info)
+
+ descr = closureDescription mod_name name
+ closure_info = mkClosureInfo False -- Not static
+ bndr lf_info tot_wds ptr_wds
+ srt_info descr
- bind_fv ((id, (_, lf_info)), offset) = bindNewToNode id offset lf_info
-
- amodes_w_offsets = [(amode,offset) | ((_, (amode,_)), offset) <- bind_details]
-
- get_kind (id, amode_and_info) = idPrimRep id
- in
-- BUILD ITS INFO TABLE AND CODE
- forkClosureBody (
- -- Bind the fvs
- mapCs bind_fv bind_details `thenC`
+ ; forkClosureBody (do
+ { -- Bind the fvs
+ let bind_fv (info, offset)
+ = bindNewToNode (cgIdInfoId info) offset (cgIdInfoLF info)
+ ; mapCs bind_fv bind_details
-- Bind the binder itself, if it is a free var
- (if binder_is_a_fv then
- bindNewToReg binder node lf_info
- else
- nopC) `thenC`
-
+ ; whenC bndr_is_a_fv (bindNewToReg bndr nodeReg lf_info)
+
-- Compile the body
- closureCodeBody binder_info closure_info cc args body
- ) `thenC`
-
- -- BUILD VAP INFO TABLES IF NECESSARY
- -- Don't build Vap info tables etc for
- -- a function whose result is an unboxed type,
- -- because we can never have thunks with such a type.
- (if closureReturnsUnboxedType closure_info then
- nopC
- else
- cgVapInfoTables False {- Not top level -} nopC binder_info binder args lf_info
- ) `thenC`
+ ; closureCodeBody bndr_info closure_info cc args body })
-- BUILD THE OBJECT
- let
- (use_cc, blame_cc) = chooseDynCostCentres cc args fvs body
- in
- allocDynClosure closure_info use_cc blame_cc amodes_w_offsets
- ) `thenFC` \ heap_offset ->
+ ; let
+ to_amode (info, offset) = do { amode <- idInfoToAmode info
+ ; return (amode, offset) }
+ ; (use_cc, blame_cc) <- chooseDynCostCentres cc args body
+ ; amodes_w_offsets <- mapFCs to_amode bind_details
+ ; heap_offset <- allocDynClosure closure_info use_cc blame_cc amodes_w_offsets
-- RETURN
- returnFC (binder, heapIdInfo binder heap_offset lf_info)
-\end{code}
-
-@cgVapInfoTables@ generates both Vap info tables, if they are required
-at all. It calls @cgVapInfoTable@ to generate each Vap info table,
-along with its entry code.
+ ; returnFC (bndr, heapIdInfo bndr heap_offset lf_info) }
-\begin{code}
--- Don't generate Vap info tables for thunks; only for functions
-cgVapInfoTables top_level perhaps_bind_the_fun binder_info fun [{- no args; a thunk! -}] lf_info
- = nopC
-
-cgVapInfoTables top_level perhaps_bind_the_fun binder_info fun args lf_info
- = -- BUILD THE STANDARD VAP-ENTRY STUFF IF NECESSARY
- (if stdVapRequired binder_info then
- cgVapInfoTable perhaps_bind_the_fun Updatable fun args fun_in_payload lf_info
- else
- nopC
- ) `thenC`
-
- -- BUILD THE NO-UPDATE VAP-ENTRY STUFF IF NECESSARY
- (if noUpdVapRequired binder_info then
- cgVapInfoTable perhaps_bind_the_fun SingleEntry fun args fun_in_payload lf_info
- else
- nopC
- )
- where
- fun_in_payload = not top_level
+mkClosureLFInfo :: Id -- The binder
+ -> TopLevelFlag -- True of top level
+ -> [Id] -- Free vars
+ -> UpdateFlag -- Update flag
+ -> [Id] -- Args
+ -> FCode LambdaFormInfo
+mkClosureLFInfo bndr top fvs upd_flag args
+ | null args = return (mkLFThunk (idType bndr) top fvs upd_flag)
+ | otherwise = do { arg_descr <- mkArgDescr (idName bndr) args
+ ; return (mkLFReEntrant top fvs args arg_descr) }
+\end{code}
-cgVapInfoTable perhaps_bind_the_fun upd_flag fun args fun_in_payload fun_lf_info
- = let
- -- The vap_entry_rhs is a manufactured STG expression which
- -- looks like the RHS of any binding which is going to use the vap-entry
- -- point of the function. Each of these bindings will look like:
- --
- -- x = [a,b,c] \upd [] -> f a b c
- --
- -- If f is not top-level, then f is one of the free variables too,
- -- hence "payload_ids" isn't the same as "arg_ids".
- --
- stg_args = map StgVarArg args
- vap_entry_rhs = StgApp (StgVarArg fun) stg_args emptyIdSet
- -- Empty live vars
-
- arg_ids_w_info = [(name,mkLFArgument) | name <- args]
- payload_ids_w_info | fun_in_payload = (fun,fun_lf_info) : arg_ids_w_info
- | otherwise = arg_ids_w_info
-
- payload_ids | fun_in_payload = fun : args -- Sigh; needed for mkClosureLFInfo
- | otherwise = args
-
- vap_lf_info = mkVapLFInfo payload_ids upd_flag fun stg_args fun_in_payload
- -- It's not top level, even if we're currently compiling a top-level
- -- function, because any VAP *use* of this function will be for a
- -- local thunk, thus
- -- let x = f p q -- x isn't top level!
- -- in ...
-
- get_kind (id, info) = idPrimRep id
-
- payload_bind_details :: [((Id, LambdaFormInfo), VirtualHeapOffset)]
- (closure_info, payload_bind_details) = layOutDynClosure
- fun
- get_kind payload_ids_w_info
- vap_lf_info
- -- The dodgy thing is that we use the "fun" as the
- -- Id to give to layOutDynClosure. This Id gets embedded in
- -- the closure_info it returns. But of course, the function doesn't
- -- have the right type to match the Vap closure. Never mind,
- -- a hack in closureType spots the special case. Otherwise that
- -- Id is just used for label construction, which is OK.
-
- bind_fv ((id,lf_info), offset) = bindNewToNode id offset lf_info
- in
- -- BUILD ITS INFO TABLE AND CODE
- forkClosureBody (
-
- -- Bind the fvs; if the fun is not in the payload, then bind_the_fun tells
- -- how to bind it. If it is in payload it'll be bound by payload_bind_details.
- perhaps_bind_the_fun `thenC`
- mapCs bind_fv payload_bind_details `thenC`
-
- -- Generate the info table and code
- closureCodeBody NoStgBinderInfo
- closure_info
- useCurrentCostCentre
- [] -- No args; it's a thunk
- vap_entry_rhs
- )
-\end{code}
%************************************************************************
%* *
\subsection[code-for-closures]{The code for closures}
\begin{code}
closureCodeBody :: StgBinderInfo
- -> ClosureInfo -- Lots of information about this closure
- -> CostCentre -- Optional cost centre attached to closure
+ -> ClosureInfo -- Lots of information about this closure
+ -> CostCentreStack -- Optional cost centre attached to closure
-> [Id]
-> StgExpr
-> Code
There are two main cases for the code for closures. If there are {\em
no arguments}, then the closure is a thunk, and not in normal form.
-So it should set up an update frame (if it is shared). Also, it has
-no argument satisfaction check, so fast and slow entry-point labels
-are the same.
+So it should set up an update frame (if it is shared).
+NB: Thunks cannot have a primitive type!
\begin{code}
-closureCodeBody binder_info closure_info cc [] body
- = -- thunks cannot have a primitive type!
-#ifdef DEBUG
- let
- (has_tycon, tycon)
- = case (closureType closure_info) of
- Nothing -> (False, panic "debug")
- Just (tc,_,_) -> (True, tc)
- in
- if has_tycon && isPrimTyCon tycon then
- pprPanic "closureCodeBody:thunk:prim type!" (ppr PprDebug tycon)
- else
-#endif
- getAbsC body_code `thenFC` \ body_absC ->
- moduleName `thenFC` \ mod_name ->
-
- absC (CClosureInfoAndCode closure_info body_absC Nothing
- stdUpd (cl_descr mod_name)
- (dataConLiveness closure_info))
- where
- cl_descr mod_name = closureDescription mod_name (closureId closure_info) [] body
-
- body_addr = CLbl (entryLabelFromCI closure_info) CodePtrRep
- body_code = profCtrC SLIT("ENT_THK") [] `thenC`
- thunkWrapper closure_info (
- -- We only enter cc after setting up update so that cc
- -- of enclosing scope will be recorded in update frame
- -- CAF/DICT functions will be subsumed by this enclosing cc
- enterCostCentreCode closure_info cc IsThunk `thenC`
- cgExpr body)
-
- stdUpd = CLbl mkErrorStdEntryLabel CodePtrRep
+closureCodeBody binder_info cl_info cc [{- No args i.e. thunk -}] body = do
+ { body_absC <- getCgStmts $ do
+ { tickyEnterThunk cl_info
+ ; ldvEnter (CmmReg nodeReg) -- NB: Node always points when profiling
+ ; thunkWrapper cl_info $ do
+ -- We only enter cc after setting up update so
+ -- that cc of enclosing scope will be recorded
+ -- in update frame CAF/DICT functions will be
+ -- subsumed by this enclosing cc
+ { enterCostCentre cl_info cc body
+ ; cgExpr body }
+ }
+
+ ; emitClosureCodeAndInfoTable cl_info [] body_absC }
\end{code}
-If there is {\em at least one argument}, then this closure is in
-normal form, so there is no need to set up an update frame. On the
-other hand, we do have to check that there are enough args, and
-perform an update if not!
+If there is /at least one argument/, then this closure is in
+normal form, so there is no need to set up an update frame.
The Macros for GrAnSim are produced at the beginning of the
argSatisfactionCheck (by calling fetchAndReschedule). There info if
Node points to closure is available. -- HWL
\begin{code}
-closureCodeBody binder_info closure_info cc all_args body
- = getEntryConvention id lf_info
- (map idPrimRep all_args) `thenFC` \ entry_conv ->
- let
- -- Figure out what is needed and what isn't
- slow_code_needed = slowFunEntryCodeRequired id binder_info entry_conv
- info_table_needed = funInfoTableRequired id binder_info lf_info
-
- -- Arg mapping for standard (slow) entry point; all args on stack
- (spA_all_args, spB_all_args, all_bxd_w_offsets, all_ubxd_w_offsets)
- = mkVirtStkOffsets
- 0 0 -- Initial virtual SpA, SpB
- idPrimRep
- all_args
-
- -- Arg mapping for the fast entry point; as many args as poss in
- -- registers; the rest on the stack
- -- arg_regs are the registers used for arg passing
- -- stk_args are the args which are passed on the stack
- --
- arg_regs = case entry_conv of
- DirectEntry lbl arity regs -> regs
- ViaNode | is_concurrent -> []
- other -> panic "closureCodeBody:arg_regs"
-
- num_arg_regs = length arg_regs
-
- (reg_args, stk_args) = splitAt num_arg_regs all_args
-
- (spA_stk_args, spB_stk_args, stk_bxd_w_offsets, stk_ubxd_w_offsets)
- = mkVirtStkOffsets
- 0 0 -- Initial virtual SpA, SpB
- idPrimRep
- stk_args
-
- -- HWL; Note: empty list of live regs in slow entry code
- -- Old version (reschedule combined with heap check);
- -- see argSatisfactionCheck for new version
- --slow_entry_code = forceHeapCheck [node] True slow_entry_code'
- -- where node = VanillaReg PtrRep 1
- --slow_entry_code = forceHeapCheck [] True slow_entry_code'
-
- slow_entry_code
- = profCtrC SLIT("ENT_FUN_STD") [] `thenC`
-
- -- Bind args, and record expected position of stk ptrs
- mapCs bindNewToAStack all_bxd_w_offsets `thenC`
- mapCs bindNewToBStack all_ubxd_w_offsets `thenC`
- setRealAndVirtualSps spA_all_args spB_all_args `thenC`
-
- argSatisfactionCheck closure_info all_args `thenC`
-
- -- OK, so there are enough args. Now we need to stuff as
- -- many of them in registers as the fast-entry code
- -- expects Note that the zipWith will give up when it hits
- -- the end of arg_regs.
-
- mapFCs getCAddrMode all_args `thenFC` \ stk_amodes ->
- absC (mkAbstractCs (zipWith assign_to_reg arg_regs stk_amodes)) `thenC`
-
- -- Now adjust real stack pointers
- adjustRealSps spA_stk_args spB_stk_args `thenC`
-
- absC (CFallThrough (CLbl fast_label CodePtrRep))
-
- assign_to_reg reg_id amode = CAssign (CReg reg_id) amode
-
- -- HWL
- -- Old version (reschedule combined with heap check);
- -- see argSatisfactionCheck for new version
- -- fast_entry_code = forceHeapCheck [] True fast_entry_code'
-
- fast_entry_code
- = profCtrC SLIT("ENT_FUN_DIRECT") [
- CLbl (mkRednCountsLabel id) PtrRep,
- CString (_PK_ (showId PprDebug id)),
- mkIntCLit stg_arity, -- total # of args
- mkIntCLit spA_stk_args, -- # passed on A stk
- mkIntCLit spB_stk_args, -- B stk (rest in regs)
- CString (_PK_ (map (showTypeCategory . idType) all_args)),
- CString SLIT(""), CString SLIT("")
-
--- Nuked for now; see comment at end of file
--- CString (_PK_ (show_wrapper_name wrapper_maybe)),
--- CString (_PK_ (show_wrapper_arg_kinds wrapper_maybe))
-
- ] `thenC`
-
- -- Bind args to regs/stack as appropriate, and
- -- record expected position of sps
- bindArgsToRegs reg_args arg_regs `thenC`
- mapCs bindNewToAStack stk_bxd_w_offsets `thenC`
- mapCs bindNewToBStack stk_ubxd_w_offsets `thenC`
- setRealAndVirtualSps spA_stk_args spB_stk_args `thenC`
-
- -- Enter the closures cc, if required
- enterCostCentreCode closure_info cc IsFunction `thenC`
-
- -- Do the business
- funWrapper closure_info arg_regs (cgExpr body)
- in
- -- Make a labelled code-block for the slow and fast entry code
- forkAbsC (if slow_code_needed then slow_entry_code else absC AbsCNop)
- `thenFC` \ slow_abs_c ->
- forkAbsC fast_entry_code `thenFC` \ fast_abs_c ->
- moduleName `thenFC` \ mod_name ->
-
- -- Now either construct the info table, or put the fast code in alone
- -- (We never have slow code without an info table)
- absC (
- if info_table_needed then
- CClosureInfoAndCode closure_info slow_abs_c (Just fast_abs_c)
- stdUpd (cl_descr mod_name)
- (dataConLiveness closure_info)
- else
- CCodeBlock fast_label fast_abs_c
- )
- where
- is_concurrent = opt_ForConcurrent
- stg_arity = length all_args
- lf_info = closureLFInfo closure_info
-
- cl_descr mod_name = closureDescription mod_name id all_args body
-
- -- Manufacture labels
- id = closureId closure_info
- fast_label = mkFastEntryLabel id stg_arity
- stdUpd = CLbl mkErrorStdEntryLabel CodePtrRep
-
-{- OLD... see note at end of file
- wrapper_maybe = get_ultimate_wrapper Nothing id
- where
- get_ultimate_wrapper deflt x -- walk all the way up a "wrapper chain"
- = case myWrapperMaybe x of
- Nothing -> deflt
- Just xx -> get_ultimate_wrapper (Just xx) xx
-
- show_wrapper_name Nothing = ""
- show_wrapper_name (Just xx) = showId PprDebug xx
-
- show_wrapper_arg_kinds Nothing = ""
- show_wrapper_arg_kinds (Just xx)
- = case (getWrapperArgTypeCategories (idType xx) (getIdStrictness xx)) of
- Nothing -> ""
- Just str -> str
--}
+closureCodeBody binder_info cl_info cc args body
+ = ASSERT( length args > 0 )
+ do { -- Get the current virtual Sp (it might not be zero,
+ -- eg. if we're compiling a let-no-escape).
+ vSp <- getVirtSp
+ ; let (reg_args, other_args) = assignCallRegs (addIdReps args)
+ (sp_top, stk_args) = mkVirtStkOffsets vSp other_args
+
+ -- Allocate the global ticky counter
+ ; let ticky_ctr_lbl = mkRednCountsLabel (closureName cl_info)
+ ; emitTickyCounter cl_info args sp_top
+
+ -- ...and establish the ticky-counter
+ -- label for this block
+ ; setTickyCtrLabel ticky_ctr_lbl $ do
+
+ -- Emit the slow-entry code
+ { reg_save_code <- mkSlowEntryCode cl_info reg_args
+
+ -- Emit the main entry code
+ ; blks <- forkProc $
+ mkFunEntryCode cl_info cc reg_args stk_args
+ sp_top reg_save_code body
+ ; emitClosureCodeAndInfoTable cl_info [] blks
+ }}
+
+
+
+mkFunEntryCode :: ClosureInfo
+ -> CostCentreStack
+ -> [(Id,GlobalReg)] -- Args in regs
+ -> [(Id,VirtualSpOffset)] -- Args on stack
+ -> VirtualSpOffset -- Last allocated word on stack
+ -> CmmStmts -- Register-save code in case of GC
+ -> StgExpr
+ -> Code
+-- The main entry code for the closure
+mkFunEntryCode cl_info cc reg_args stk_args sp_top reg_save_code body = do
+ { -- Bind args to regs/stack as appropriate,
+ -- and record expected position of sps
+ ; bindArgsToRegs reg_args
+ ; bindArgsToStack stk_args
+ ; setRealAndVirtualSp sp_top
+
+ -- Enter the cost-centre, if required
+ -- ToDo: It's not clear why this is outside the funWrapper,
+ -- but the tickyEnterFun is inside. Perhaps we can put
+ -- them together?
+ ; enterCostCentre cl_info cc body
+
+ -- Do the business
+ ; funWrapper cl_info reg_args reg_save_code $ do
+ { tickyEnterFun cl_info
+ ; cgExpr body }
+ }
\end{code}
-For lexically scoped profiling we have to load the cost centre from
-the closure entered, if the costs are not supposed to be inherited.
-This is done immediately on entering the fast entry point.
-
-Load current cost centre from closure, if not inherited.
-Node is guaranteed to point to it, if profiling and not inherited.
+The "slow entry" code for a function. This entry point takes its
+arguments on the stack. It loads the arguments into registers
+according to the calling convention, and jumps to the function's
+normal entry point. The function's closure is assumed to be in
+R1/node.
-\begin{code}
-data IsThunk = IsThunk | IsFunction -- Bool-like, local
---#ifdef DEBUG
- deriving Eq
---#endif
-
-enterCostCentreCode :: ClosureInfo -> CostCentre -> IsThunk -> Code
-
-enterCostCentreCode closure_info cc is_thunk
- = costCentresFlag `thenFC` \ profiling_on ->
- if not profiling_on then
- nopC
- else
- ASSERT(not (noCostCentreAttached cc))
-
- if costsAreSubsumed cc then
- --ASSERT(isToplevClosure closure_info)
- --ASSERT(is_thunk == IsFunction)
- (if isToplevClosure closure_info && is_thunk == IsFunction then \x->x else pprTrace "enterCostCenterCode:" (hsep [ppr PprDebug (is_thunk == IsFunction){-, ppr PprDebug closure_info-}, text (showCostCentre PprDebug False cc)])) $
- costCentresC SLIT("ENTER_CC_FSUB") []
-
- else if currentOrSubsumedCosts cc then
- -- i.e. current; subsumed dealt with above
- -- get CCC out of the closure, where we put it when we alloc'd
- case is_thunk of
- IsThunk -> costCentresC SLIT("ENTER_CC_TCL") [CReg node]
- IsFunction -> costCentresC SLIT("ENTER_CC_FCL") [CReg node]
-
- else if isCafCC cc && isToplevClosure closure_info then
- ASSERT(is_thunk == IsThunk)
- costCentresC SLIT("ENTER_CC_CAF") [mkCCostCentre cc]
-
- else -- we've got a "real" cost centre right here in our hands...
- case is_thunk of
- IsThunk -> costCentresC SLIT("ENTER_CC_T") [mkCCostCentre cc]
- IsFunction -> if isCafCC cc || isDictCC cc
- then costCentresC SLIT("ENTER_CC_FCAF") [mkCCostCentre cc]
- else costCentresC SLIT("ENTER_CC_FLOAD") [mkCCostCentre cc]
-\end{code}
-
-%************************************************************************
-%* *
-\subsubsection[pre-closure-code-stuff]{Pre-closure-code code}
-%* *
-%************************************************************************
+The slow entry point is used in two places:
-The argument-satisfaction check code is placed after binding
-the arguments to their stack locations. Hence, the virtual stack
-pointer is pointing after all the args, and virtual offset 1 means
-the base of frame and hence most distant arg. Hence
-virtual offset 0 is just beyond the most distant argument; the
-relative offset of this word tells how many words of arguments
-are expected.
+ (a) unknown calls: eg. stg_PAP_entry
+ (b) returning from a heap-check failure
\begin{code}
-argSatisfactionCheck :: ClosureInfo -> [Id] -> Code
-
-argSatisfactionCheck closure_info [] = nopC
-
-argSatisfactionCheck closure_info args
- = -- safest way to determine which stack last arg will be on:
- -- look up CAddrMode that last arg is bound to;
- -- getAmodeRep;
- -- check isFollowableRep.
-
- nodeMustPointToIt (closureLFInfo closure_info) `thenFC` \ node_points ->
-
- let
- emit_gran_macros = opt_GranMacros
- in
-
- -- HWL ngo' ngoq:
- -- absC (CMacroStmt GRAN_FETCH []) `thenC`
- -- forceHeapCheck [] node_points (absC AbsCNop) `thenC`
- (if emit_gran_macros
- then if node_points
- then fetchAndReschedule [] node_points
- else yield [] node_points
- else absC AbsCNop) `thenC`
-
- getCAddrMode (last args) `thenFC` \ last_amode ->
-
- if (isFollowableRep (getAmodeRep last_amode)) then
- getSpARelOffset 0 `thenFC` \ (SpARel spA off) ->
- let
- a_rel_int = spARelToInt spA off
- a_rel_arg = mkIntCLit a_rel_int
- in
- ASSERT(a_rel_int /= 0)
- if node_points then
- absC (CMacroStmt ARGS_CHK_A [a_rel_arg])
- else
- absC (CMacroStmt ARGS_CHK_A_LOAD_NODE [a_rel_arg, set_Node_to_this])
- else
- getSpBRelOffset 0 `thenFC` \ (SpBRel spB off) ->
- let
- b_rel_int = spBRelToInt spB off
- b_rel_arg = mkIntCLit b_rel_int
- in
- ASSERT(b_rel_int /= 0)
- if node_points then
- absC (CMacroStmt ARGS_CHK_B [b_rel_arg])
- else
- absC (CMacroStmt ARGS_CHK_B_LOAD_NODE [b_rel_arg, set_Node_to_this])
+mkSlowEntryCode :: ClosureInfo -> [(Id,GlobalReg)] -> FCode CmmStmts
+-- If this function doesn't have a specialised ArgDescr, we need
+-- to generate the function's arg bitmap, slow-entry code, and
+-- register-save code for the heap-check failure
+-- Here, we emit the slow-entry code, and
+-- return the register-save assignments
+mkSlowEntryCode cl_info reg_args
+ | Just (_, ArgGen _) <- closureFunInfo cl_info
+ = do { emitSimpleProc slow_lbl (emitStmts load_stmts)
+ ; return save_stmts }
+ | otherwise = return noStmts
where
- -- We must tell the arg-satis macro whether Node is pointing to
- -- the closure or not. If it isn't so pointing, then we give to
- -- the macro the (static) address of the closure.
-
- set_Node_to_this = CLbl (closureLabelFromCI closure_info) PtrRep
+ name = closureName cl_info
+ slow_lbl = mkSlowEntryLabel name
+
+ load_stmts = mkStmts load_assts `plusStmts` mkStmts [stk_adj_pop, jump_to_entry]
+ save_stmts = oneStmt stk_adj_push `plusStmts` mkStmts save_assts
+
+ reps_w_regs :: [(CgRep,GlobalReg)]
+ reps_w_regs = [(idCgRep id, reg) | (id,reg) <- reverse reg_args]
+ (final_stk_offset, stk_offsets)
+ = mapAccumL (\off (rep,_) -> (off + cgRepSizeW rep, off))
+ 0 reps_w_regs
+
+ load_assts = zipWithEqual "mk_load" mk_load reps_w_regs stk_offsets
+ mk_load (rep,reg) offset = CmmAssign (CmmGlobal reg)
+ (CmmLoad (cmmRegOffW spReg offset)
+ (argMachRep rep))
+
+ save_assts = zipWithEqual "mk_save" mk_save reps_w_regs stk_offsets
+ mk_save (rep,reg) offset = ASSERT( argMachRep rep == globalRegRep reg )
+ CmmStore (cmmRegOffW spReg offset)
+ (CmmReg (CmmGlobal reg))
+
+ stk_adj_pop = CmmAssign spReg (cmmRegOffW spReg final_stk_offset)
+ stk_adj_push = CmmAssign spReg (cmmRegOffW spReg (- final_stk_offset))
+ jump_to_entry = CmmJump (mkLblExpr (enterLocalIdLabel name)) []
\end{code}
+
%************************************************************************
%* *
\subsubsection[closure-code-wrappers]{Wrappers around closure code}
\begin{code}
thunkWrapper:: ClosureInfo -> Code -> Code
-thunkWrapper closure_info thunk_code
- = -- Stack and heap overflow checks
- nodeMustPointToIt (closureLFInfo closure_info) `thenFC` \ node_points ->
-
- let
- emit_gran_macros = opt_GranMacros
- in
- -- HWL: insert macros for GrAnSim; 2 versions depending on liveness of node
- -- (we prefer fetchAndReschedule-style context switches to yield ones)
- (if emit_gran_macros
- then if node_points
- then fetchAndReschedule [] node_points
- else yield [] node_points
- else absC AbsCNop) `thenC`
-
- stackCheck closure_info [] node_points ( -- stackCheck *encloses* the rest
-
- -- heapCheck must be after stackCheck: if stchk fails
- -- new stack space is allocated from the heap which
- -- would violate any previous heapCheck
-
- heapCheck [] node_points ( -- heapCheck *encloses* the rest
- -- The "[]" says there are no live argument registers
-
- -- Overwrite with black hole if necessary
- blackHoleIt closure_info `thenC`
-
- setupUpdate closure_info ( -- setupUpdate *encloses* the rest
-
- -- Finally, do the business
- thunk_code
- )))
+thunkWrapper closure_info thunk_code = do
+ { let node_points = nodeMustPointToIt (closureLFInfo closure_info)
+
+ -- HWL: insert macros for GrAnSim; 2 versions depending on liveness of node
+ -- (we prefer fetchAndReschedule-style context switches to yield ones)
+ ; if node_points
+ then granFetchAndReschedule [] node_points
+ else granYield [] node_points
+
+ -- Stack and/or heap checks
+ ; thunkEntryChecks closure_info $ do
+ { -- Overwrite with black hole if necessary
+ whenC (blackHoleOnEntry closure_info && node_points)
+ (blackHoleIt closure_info)
+ ; setupUpdate closure_info thunk_code }
+ -- setupUpdate *encloses* the thunk_code
+ }
funWrapper :: ClosureInfo -- Closure whose code body this is
- -> [MagicId] -- List of argument registers (if any)
+ -> [(Id,GlobalReg)] -- List of argument registers (if any)
+ -> CmmStmts -- reg saves for the heap check failure
-> Code -- Body of function being compiled
-> Code
-funWrapper closure_info arg_regs fun_body
- = -- Stack overflow check
- nodeMustPointToIt (closureLFInfo closure_info) `thenFC` \ node_points ->
- let
- emit_gran_macros = opt_GranMacros
- in
- -- HWL chu' ngoq:
- (if emit_gran_macros
- then yield arg_regs node_points
- else absC AbsCNop) `thenC`
-
- stackCheck closure_info arg_regs node_points (
- -- stackCheck *encloses* the rest
-
- heapCheck arg_regs node_points (
- -- heapCheck *encloses* the rest
-
- -- Finally, do the business
- fun_body
- ))
-\end{code}
-
-%************************************************************************
-%* *
-\subsubsubsection[overflow-checks]{Stack and heap overflow wrappers}
-%* *
-%************************************************************************
+funWrapper closure_info arg_regs reg_save_code fun_body = do
+ { let node_points = nodeMustPointToIt (closureLFInfo closure_info)
-Assumption: virtual and real stack pointers are currently exactly aligned.
+ -- Enter for Ldv profiling
+ ; whenC node_points (ldvEnter (CmmReg nodeReg))
-\begin{code}
-stackCheck :: ClosureInfo
- -> [MagicId] -- Live registers
- -> Bool -- Node required to point after check?
- -> Code
- -> Code
-
-stackCheck closure_info regs node_reqd code
- = getFinalStackHW (\ aHw -> \ bHw -> -- Both virtual stack offsets
-
- getVirtSps `thenFC` \ (vSpA, vSpB) ->
-
- let a_headroom_reqd = aHw - vSpA -- Virtual offsets are positive integers
- b_headroom_reqd = bHw - vSpB
- in
-
- absC (if (a_headroom_reqd == 0 && b_headroom_reqd == 0) then
- AbsCNop
- else
- CMacroStmt STK_CHK [mkIntCLit liveness_mask,
- mkIntCLit a_headroom_reqd,
- mkIntCLit b_headroom_reqd,
- mkIntCLit vSpA,
- mkIntCLit vSpB,
- mkIntCLit (if returns_prim_type then 1 else 0),
- mkIntCLit (if node_reqd then 1 else 0)]
- )
- -- The test is *inside* the absC, to avoid black holes!
-
- `thenC` code
- )
- where
- all_regs = if node_reqd then node:regs else regs
- liveness_mask = mkLiveRegsMask all_regs
+ -- GranSim yeild poin
+ ; granYield arg_regs node_points
- returns_prim_type = closureReturnsUnboxedType closure_info
+ -- Heap and/or stack checks wrap the function body
+ ; funEntryChecks closure_info reg_save_code
+ fun_body
+ }
\end{code}
+
%************************************************************************
%* *
\subsubsubsection[update-and-BHs]{Update and black-hole wrappers}
\begin{code}
-blackHoleIt :: ClosureInfo -> Code -- Only called for thunks
-blackHoleIt closure_info
- = noBlackHolingFlag `thenFC` \ no_black_holing ->
-
- if (blackHoleOnEntry no_black_holing closure_info)
- then
- absC (if closureSingleEntry(closure_info) then
- CMacroStmt UPD_BH_SINGLE_ENTRY [CReg node]
- else
- CMacroStmt UPD_BH_UPDATABLE [CReg node])
- -- Node always points to it; see stg-details
- else
+blackHoleIt :: ClosureInfo -> Code
+-- Only called for closures with no args
+-- Node points to the closure
+blackHoleIt closure_info = emitBlackHoleCode (closureSingleEntry closure_info)
+
+emitBlackHoleCode :: Bool -> Code
+emitBlackHoleCode is_single_entry
+ | eager_blackholing = do
+ tickyBlackHole (not is_single_entry)
+ stmtC (CmmStore (CmmReg nodeReg) (CmmLit (CmmLabel bh_lbl)))
+ | otherwise =
nopC
+ where
+ bh_lbl | is_single_entry = mkRtsDataLabel SLIT("stg_SE_BLACKHOLE_info")
+ | otherwise = mkRtsDataLabel SLIT("stg_BLACKHOLE_info")
+
+ -- 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]
+ --
+ -- Profiling needs slop filling (to support LDV profiling), so
+ -- currently eager blackholing doesn't work with profiling.
+ --
+ -- TICKY_TICKY needs EAGER_BLACKHOLING to verify no double-entries of
+ -- single-entry thunks.
+ eager_blackholing
+ | opt_DoTickyProfiling = True
+ | otherwise = False
+
\end{code}
\begin{code}
-setupUpdate :: ClosureInfo -> Code -> Code -- Only called for thunks
+setupUpdate :: ClosureInfo -> Code -> Code -- Only called for closures with no args
-- Nota Bene: this function does not change Node (even if it's a CAF),
-- so that the cost centre in the original closure can still be
- -- extracted by a subsequent ENTER_CC_TCL
-
+ -- extracted by a subsequent enterCostCentre
setupUpdate closure_info code
- = if (closureUpdReqd closure_info) then
- link_caf_if_needed `thenFC` \ update_closure ->
- pushUpdateFrame update_closure vector code
- else
- profCtrC SLIT("UPDF_OMITTED") [] `thenC`
- code
- where
- link_caf_if_needed :: FCode CAddrMode -- Returns amode for closure to be updated
- link_caf_if_needed
- = if not (isStaticClosure closure_info) then
- returnFC (CReg node)
- else
-
- -- First we must allocate a black hole, and link the
- -- CAF onto the CAF list
-
- -- Alloc black hole specifying CC_HDR(Node) as the cost centre
- -- Hack Warning: Using a CLitLit to get CAddrMode !
- let
- use_cc = CLitLit SLIT("CC_HDR(R1.p)") PtrRep
- blame_cc = use_cc
- in
- allocDynClosure (blackHoleClosureInfo closure_info) use_cc blame_cc []
- `thenFC` \ heap_offset ->
- getHpRelOffset heap_offset `thenFC` \ hp_rel ->
- let amode = CAddr hp_rel
- in
- absC (CMacroStmt UPD_CAF [CReg node, amode])
- `thenC`
- returnFC amode
-
- vector
- = case (closureType closure_info) of
- Nothing -> CReg StdUpdRetVecReg
- Just (spec_tycon, _, spec_datacons) ->
- case (ctrlReturnConvAlg spec_tycon) of
- UnvectoredReturn 1 ->
- let
- spec_data_con = head spec_datacons
- only_tag = dataConTag spec_data_con
-
- direct = case (dataReturnConvAlg spec_data_con) of
- ReturnInRegs _ -> mkConUpdCodePtrVecLabel spec_tycon only_tag
- ReturnInHeap -> mkStdUpdCodePtrVecLabel spec_tycon only_tag
-
- vectored = mkStdUpdVecTblLabel spec_tycon
- in
- CUnVecLbl direct vectored
-
- UnvectoredReturn _ -> CReg StdUpdRetVecReg
- VectoredReturn _ -> CLbl (mkStdUpdVecTblLabel spec_tycon) DataPtrRep
+ | closureReEntrant closure_info
+ = code
+
+ | not (isStaticClosure closure_info)
+ = if closureUpdReqd closure_info
+ then do { tickyPushUpdateFrame; pushUpdateFrame (CmmReg nodeReg) code }
+ else do { tickyUpdateFrameOmitted; code }
+
+ | otherwise -- A static closure
+ = do { tickyUpdateBhCaf closure_info
+
+ ; if closureUpdReqd closure_info
+ then do -- Blackhole the (updatable) CAF:
+ { upd_closure <- link_caf closure_info True
+ ; pushUpdateFrame upd_closure code }
+ else do
+ { -- No update reqd, you'd think we don't need to
+ -- black-hole it. But when ticky-ticky is on, we
+ -- black-hole it regardless, to catch errors in which
+ -- an allegedly single-entry closure is entered twice
+ --
+ -- We discard the pointer returned by link_caf, because
+ -- we don't push an update frame
+ whenC opt_DoTickyProfiling -- Blackhole even a SE CAF
+ (link_caf closure_info False >> nopC)
+ ; tickyUpdateFrameOmitted
+ ; code }
+ }
+
+
+-----------------------------------------------------------------------------
+-- Entering a CAF
+--
+-- When a CAF is first entered, it creates a black hole in the heap,
+-- and updates itself with an indirection to this new black hole.
+--
+-- We update the CAF with an indirection to a newly-allocated black
+-- hole in the heap. We also set the blocking queue on the newly
+-- allocated black hole to be empty.
+--
+-- Why do we make a black hole in the heap when we enter a CAF?
+--
+-- - for a generational garbage collector, which needs a fast
+-- test for whether an updatee is in an old generation or not
+--
+-- - for the parallel system, which can implement updates more
+-- easily if the updatee is always in the heap. (allegedly).
+--
+-- When debugging, we maintain a separate CAF list so we can tell when
+-- a CAF has been garbage collected.
+
+-- newCAF must be called before the itbl ptr is overwritten, since
+-- newCAF records the old itbl ptr in order to do CAF reverting
+-- (which Hugs needs to do in order that combined mode works right.)
+--
+
+-- ToDo [Feb 04] This entire link_caf nonsense could all be moved
+-- into the "newCAF" RTS procedure, which we call anyway, including
+-- the allocation of the black-hole indirection closure.
+-- That way, code size would fall, the CAF-handling code would
+-- be closer together, and the compiler wouldn't need to know
+-- about off_indirectee etc.
+
+link_caf :: ClosureInfo
+ -> Bool -- True <=> updatable, False <=> single-entry
+ -> FCode CmmExpr -- Returns amode for closure to be updated
+-- To update a CAF we must allocate a black hole, link the CAF onto the
+-- CAF list, then update the CAF to point to the fresh black hole.
+-- This function returns the address of the black hole, so it can be
+-- updated with the new value when available. The reason for all of this
+-- is that we only want to update dynamic heap objects, not static ones,
+-- so that generational GC is easier.
+link_caf cl_info is_upd = do
+ { -- Alloc black hole specifying CC_HDR(Node) as the cost centre
+ ; let use_cc = costCentreFrom (CmmReg nodeReg)
+ blame_cc = use_cc
+ ; hp_offset <- allocDynClosure bh_cl_info use_cc blame_cc []
+ ; hp_rel <- getHpRelOffset hp_offset
+
+ -- Call the RTS function newCAF to add the CAF to the CafList
+ -- so that the garbage collector can find them
+ -- This must be done *before* the info table pointer is overwritten,
+ -- because the old info table ptr is needed for reversion
+ ; emitRtsCallWithVols SLIT("newCAF") [(CmmReg nodeReg,PtrHint)] [node]
+ -- node is live, so save it.
+
+ -- Overwrite the closure with a (static) indirection
+ -- to the newly-allocated black hole
+ ; stmtsC [ CmmStore (cmmRegOffW nodeReg off_indirectee) hp_rel
+ , CmmStore (CmmReg nodeReg) ind_static_info ]
+
+ ; returnFC hp_rel }
+ where
+ bh_cl_info :: ClosureInfo
+ bh_cl_info | is_upd = cafBlackHoleClosureInfo cl_info
+ | otherwise = seCafBlackHoleClosureInfo cl_info
+
+ ind_static_info :: CmmExpr
+ ind_static_info = mkLblExpr mkIndStaticInfoLabel
+
+ off_indirectee :: WordOff
+ off_indirectee = fixedHdrSize + oFFSET_StgInd_indirectee*wORD_SIZE
\end{code}
+
%************************************************************************
%* *
\subsection[CgClosure-Description]{Profiling Closure Description.}
%************************************************************************
For "global" data constructors the description is simply occurrence
-name of the data constructor itself (see \ref{CgConTbls-info-tables}).
-
-Otherwise it is determind by @closureDescription@ from the let
-binding information.
+name of the data constructor itself. Otherwise it is determined by
+@closureDescription@ from the let binding information.
\begin{code}
-closureDescription :: FAST_STRING -- Module
- -> Id -- Id of closure binding
- -> [Id] -- Args
- -> StgExpr -- Body
+closureDescription :: Module -- Module
+ -> Name -- Id of closure binding
-> String
-
-- Not called for StgRhsCon which have global info tables built in
-- CgConTbls.lhs with a description generated from the data constructor
-
-closureDescription mod_name name args body
- = show (
- hcat [char '<',
- ptext mod_name,
- char '.',
- ppr PprDebug name,
- char '>'])
-\end{code}
-
-\begin{code}
-chooseDynCostCentres cc args fvs body
- = let
- use_cc -- cost-centre we record in the object
- = if currentOrSubsumedCosts cc
- then CReg CurCostCentre
- else mkCCostCentre cc
-
- blame_cc -- cost-centre on whom we blame the allocation
- = case (args, fvs, body) of
- ([], [just1], StgApp (StgVarArg fun) [{-no args-}] _)
- | just1 == fun
- -> mkCCostCentre overheadCostCentre
- _ -> use_cc
-
- -- if it's an utterly trivial RHS, then it must be
- -- one introduced by boxHigherOrderArgs for profiling,
- -- so we charge it to "OVERHEAD".
- in
- (use_cc, blame_cc)
+closureDescription mod_name name
+ = showSDocDump (char '<' <>
+ (if isExternalName name
+ then ppr name -- ppr will include the module name prefix
+ else pprModule mod_name <> char '.' <> ppr name) <>
+ char '>')
+ -- showSDocDump, because we want to see the unique on the Name.
\end{code}
-
-
-
-========================================================================
-OLD CODE THAT EMITTED INFORMATON FOR QUANTITATIVE ANALYSIS
-
-It's pretty wierd, so I've nuked it for now. SLPJ Nov 96
-
-\begin{pseudocode}
-getWrapperArgTypeCategories
- :: Type -- wrapper's type
- -> StrictnessInfo bdee -- strictness info about its args
- -> Maybe String
-
-getWrapperArgTypeCategories _ NoStrictnessInfo = Nothing
-getWrapperArgTypeCategories _ BottomGuaranteed
- = trace "getWrapperArgTypeCategories:BottomGuaranteed!" Nothing -- wrong
-getWrapperArgTypeCategories _ (StrictnessInfo [] _) = Nothing
-
-getWrapperArgTypeCategories ty (StrictnessInfo arg_info _)
- = Just (mkWrapperArgTypeCategories ty arg_info)
-
-mkWrapperArgTypeCategories
- :: Type -- wrapper's type
- -> [Demand] -- info about its arguments
- -> String -- a string saying lots about the args
-
-mkWrapperArgTypeCategories wrapper_ty wrap_info
- = case (splitFunTyExpandingDicts wrapper_ty) of { (arg_tys,_) ->
- map do_one (wrap_info `zip` (map showTypeCategory arg_tys)) }
- where
- -- ToDo: this needs FIXING UP (it was a hack anyway...)
- do_one (WwPrim, _) = 'P'
- do_one (WwEnum, _) = 'E'
- do_one (WwStrict, arg_ty_char) = arg_ty_char
- do_one (WwUnpack _ _ _, arg_ty_char)
- = if arg_ty_char `elem` "CIJFDTS"
- then toLower arg_ty_char
- else if arg_ty_char == '+' then 't'
- else trace ("mkWrapp..:funny char:"++[arg_ty_char]) '-'
- do_one (other_wrap_info, _) = '-'
-\end{pseudocode}
-
+
projects / ghc-hetmet.git / blobdiff