2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
4 \section[CgClosure]{Code generation for closures}
6 This module provides the support code for @StgToAbstractC@ to deal
7 with {\em closures} on the RHSs of let(rec)s. See also
8 @CgCon@, which deals with constructors.
11 #include "HsVersions.h"
13 module CgClosure ( cgTopRhsClosure, cgRhsClosure ) where
16 IMPORT_DELOOPER(CgLoop2) ( cgExpr )
22 import AbsCUtils ( mkAbstractCs, getAmodeRep )
23 import CgBindery ( getCAddrMode, getArgAmodes,
24 getCAddrModeAndInfo, bindNewToNode,
25 bindNewToAStack, bindNewToBStack,
26 bindNewToReg, bindArgsToRegs,
27 stableAmodeIdInfo, heapIdInfo, CgIdInfo
29 import CgCompInfo ( spARelToInt, spBRelToInt )
30 import CgUpdate ( pushUpdateFrame )
31 import CgHeapery ( allocDynClosure, heapCheck
32 , heapCheckOnly, fetchAndReschedule, yield -- HWL
34 import CgRetConv ( ctrlReturnConvAlg, dataReturnConvAlg,
35 CtrlReturnConvention(..), DataReturnConvention(..)
37 import CgStackery ( getFinalStackHW, mkVirtStkOffsets,
40 import CgUsages ( getVirtSps, setRealAndVirtualSps,
41 getSpARelOffset, getSpBRelOffset,
44 import CLabel ( mkClosureLabel, mkConUpdCodePtrVecLabel,
45 mkStdUpdCodePtrVecLabel, mkStdUpdVecTblLabel,
46 mkErrorStdEntryLabel, mkRednCountsLabel
48 import ClosureInfo -- lots and lots of stuff
49 import CmdLineOpts ( opt_ForConcurrent, opt_GranMacros )
50 import CostCentre ( useCurrentCostCentre, currentOrSubsumedCosts,
51 noCostCentreAttached, costsAreSubsumed,
52 isCafCC, isDictCC, overheadCostCentre, showCostCentre
54 import HeapOffs ( SYN_IE(VirtualHeapOffset) )
55 import Id ( idType, idPrimRep,
56 showId, getIdStrictness, dataConTag,
58 GenId{-instance Outputable-}
60 import ListSetOps ( minusList )
61 import Maybes ( maybeToBool )
62 import Outputable ( Outputable(..){-instances-} ) -- ToDo:rm
63 import PprStyle ( PprStyle(..) )
64 import PprType ( GenType{-instance Outputable-}, TyCon{-ditto-} )
65 import Pretty ( prettyToUn, ppBesides, ppChar, ppPStr, ppCat, ppStr )
66 import PrimRep ( isFollowableRep, PrimRep(..) )
67 import TyCon ( isPrimTyCon, tyConDataCons )
68 import Unpretty ( uppShow )
69 import Util ( isIn, panic, pprPanic, assertPanic, pprTrace{-ToDo:rm-} )
71 myWrapperMaybe = panic "CgClosure.myWrapperMaybe (ToDo)"
72 showTypeCategory = panic "CgClosure.showTypeCategory (ToDo)"
73 getWrapperArgTypeCategories = panic "CgClosure.getWrapperArgTypeCategories (ToDo)"
76 %********************************************************
78 \subsection[closures-no-free-vars]{Top-level closures}
80 %********************************************************
82 For closures bound at top level, allocate in static space.
83 They should have no free variables.
87 -> CostCentre -- Optional cost centre annotation
92 -> FCode (Id, CgIdInfo)
94 cgTopRhsClosure name cc binder_info args body lf_info
95 = -- LAY OUT THE OBJECT
97 closure_info = layOutStaticNoFVClosure name lf_info
100 -- GENERATE THE INFO TABLE (IF NECESSARY)
101 forkClosureBody (closureCodeBody binder_info closure_info
105 -- BUILD VAP INFO TABLES IF NECESSARY
106 -- Don't build Vap info tables etc for
107 -- a function whose result is an unboxed type,
108 -- because we can never have thunks with such a type.
109 (if closureReturnsUnboxedType closure_info then
113 bind_the_fun = addBindC name cg_id_info -- It's global!
115 cgVapInfoTables True {- Top level -} bind_the_fun binder_info name args lf_info
118 -- BUILD THE OBJECT (IF NECESSARY)
119 (if staticClosureRequired name binder_info lf_info
122 cost_centre = mkCCostCentre cc
125 closure_label -- Labelled with the name on lhs of defn
133 returnFC (name, cg_id_info)
135 closure_label = mkClosureLabel name
136 cg_id_info = stableAmodeIdInfo name (CLbl closure_label PtrRep) lf_info
139 %********************************************************
141 \subsection[non-top-level-closures]{Non top-level closures}
143 %********************************************************
145 For closures with free vars, allocate in heap.
147 ===================== OLD PROBABLY OUT OF DATE COMMENTS =============
149 -- Closures which (a) have no fvs and (b) have some args (i.e.
150 -- combinator functions), are allocated statically, just as if they
151 -- were top-level closures. We can't get a space leak that way
152 -- (because they are HNFs) and it saves allocation.
154 -- Lexical Scoping: Problem
155 -- These top level function closures will be inherited, possibly
156 -- to a different cost centre scope set before entering.
158 -- Evaluation Scoping: ok as already in HNF
160 -- Should rely on floating mechanism to achieve this floating to top level.
161 -- As let floating will avoid floating which breaks cost centre attribution
162 -- everything will be OK.
164 -- Disabled: because it breaks lexical-scoped cost centre semantics.
165 -- cgRhsClosure binder cc bi [] upd_flag args@(_:_) body
166 -- = cgTopRhsClosure binder cc bi upd_flag args body
168 ===================== END OF OLD PROBABLY OUT OF DATE COMMENTS =============
172 -> CostCentre -- Optional cost centre annotation
178 -> FCode (Id, CgIdInfo)
180 cgRhsClosure binder cc binder_info fvs args body lf_info
181 | maybeToBool maybe_std_thunk -- AHA! A STANDARD-FORM THUNK
182 -- ToDo: check non-primitiveness (ASSERT)
184 -- LAY OUT THE OBJECT
185 getArgAmodes std_thunk_payload `thenFC` \ amodes ->
187 (closure_info, amodes_w_offsets)
188 = layOutDynClosure binder getAmodeRep amodes lf_info
190 (use_cc, blame_cc) = chooseDynCostCentres cc args fvs body
193 allocDynClosure closure_info use_cc blame_cc amodes_w_offsets
195 `thenFC` \ heap_offset ->
198 returnFC (binder, heapIdInfo binder heap_offset lf_info)
201 maybe_std_thunk = getStandardFormThunkInfo lf_info
202 Just std_thunk_payload = maybe_std_thunk
205 Here's the general case.
207 cgRhsClosure binder cc binder_info fvs args body lf_info
209 -- LAY OUT THE OBJECT
211 -- If the binder is itself a free variable, then don't store
212 -- it in the closure. Instead, just bind it to Node on entry.
213 -- NB we can be sure that Node will point to it, because we
214 -- havn't told mkClosureLFInfo about this; so if the binder
215 -- *was* a free var of its RHS, mkClosureLFInfo thinks it *is*
216 -- stored in the closure itself, so it will make sure that
217 -- Node points to it...
219 is_elem = isIn "cgRhsClosure"
221 binder_is_a_fv = binder `is_elem` fvs
222 reduced_fvs = if binder_is_a_fv
223 then fvs `minusList` [binder]
226 mapFCs getCAddrModeAndInfo reduced_fvs `thenFC` \ amodes_and_info ->
228 fvs_w_amodes_and_info = reduced_fvs `zip` amodes_and_info
230 closure_info :: ClosureInfo
231 bind_details :: [((Id, (CAddrMode, LambdaFormInfo)), VirtualHeapOffset)]
233 (closure_info, bind_details)
234 = layOutDynClosure binder get_kind fvs_w_amodes_and_info lf_info
236 bind_fv ((id, (_, lf_info)), offset) = bindNewToNode id offset lf_info
238 amodes_w_offsets = [(amode,offset) | ((_, (amode,_)), offset) <- bind_details]
240 get_kind (id, amode_and_info) = idPrimRep id
242 -- BUILD ITS INFO TABLE AND CODE
245 mapCs bind_fv bind_details `thenC`
247 -- Bind the binder itself, if it is a free var
248 (if binder_is_a_fv then
249 bindNewToReg binder node lf_info
254 closureCodeBody binder_info closure_info cc args body
257 -- BUILD VAP INFO TABLES IF NECESSARY
258 -- Don't build Vap info tables etc for
259 -- a function whose result is an unboxed type,
260 -- because we can never have thunks with such a type.
261 (if closureReturnsUnboxedType closure_info then
264 cgVapInfoTables False {- Not top level -} nopC binder_info binder args lf_info
269 (use_cc, blame_cc) = chooseDynCostCentres cc args fvs body
271 allocDynClosure closure_info use_cc blame_cc amodes_w_offsets
272 ) `thenFC` \ heap_offset ->
275 returnFC (binder, heapIdInfo binder heap_offset lf_info)
278 @cgVapInfoTables@ generates both Vap info tables, if they are required
279 at all. It calls @cgVapInfoTable@ to generate each Vap info table,
280 along with its entry code.
283 -- Don't generate Vap info tables for thunks; only for functions
284 cgVapInfoTables top_level perhaps_bind_the_fun binder_info fun [{- no args; a thunk! -}] lf_info
287 cgVapInfoTables top_level perhaps_bind_the_fun binder_info fun args lf_info
288 = -- BUILD THE STANDARD VAP-ENTRY STUFF IF NECESSARY
289 (if stdVapRequired binder_info then
290 cgVapInfoTable perhaps_bind_the_fun Updatable fun args fun_in_payload lf_info
295 -- BUILD THE NO-UPDATE VAP-ENTRY STUFF IF NECESSARY
296 (if noUpdVapRequired binder_info then
297 cgVapInfoTable perhaps_bind_the_fun SingleEntry fun args fun_in_payload lf_info
303 fun_in_payload = not top_level
305 cgVapInfoTable perhaps_bind_the_fun upd_flag fun args fun_in_payload fun_lf_info
307 -- The vap_entry_rhs is a manufactured STG expression which
308 -- looks like the RHS of any binding which is going to use the vap-entry
309 -- point of the function. Each of these bindings will look like:
311 -- x = [a,b,c] \upd [] -> f a b c
313 -- If f is not top-level, then f is one of the free variables too,
314 -- hence "payload_ids" isn't the same as "arg_ids".
316 vap_entry_rhs = StgApp (StgVarArg fun) (map StgVarArg args) emptyIdSet
319 arg_ids_w_info = [(name,mkLFArgument) | name <- args]
320 payload_ids_w_info | fun_in_payload = (fun,fun_lf_info) : arg_ids_w_info
321 | otherwise = arg_ids_w_info
323 payload_ids | fun_in_payload = fun : args -- Sigh; needed for mkClosureLFInfo
326 vap_lf_info = mkClosureLFInfo False {-not top level-} payload_ids
327 upd_flag [] vap_entry_rhs
328 -- It's not top level, even if we're currently compiling a top-level
329 -- function, because any VAP *use* of this function will be for a
331 -- let x = f p q -- x isn't top level!
334 get_kind (id, info) = idPrimRep id
336 payload_bind_details :: [((Id, LambdaFormInfo), VirtualHeapOffset)]
337 (closure_info, payload_bind_details) = layOutDynClosure
339 get_kind payload_ids_w_info
341 -- The dodgy thing is that we use the "fun" as the
342 -- Id to give to layOutDynClosure. This Id gets embedded in
343 -- the closure_info it returns. But of course, the function doesn't
344 -- have the right type to match the Vap closure. Never mind,
345 -- a hack in closureType spots the special case. Otherwise that
346 -- Id is just used for label construction, which is OK.
348 bind_fv ((id,lf_info), offset) = bindNewToNode id offset lf_info
351 -- BUILD ITS INFO TABLE AND CODE
354 -- Bind the fvs; if the fun is not in the payload, then bind_the_fun tells
355 -- how to bind it. If it is in payload it'll be bound by payload_bind_details.
356 perhaps_bind_the_fun `thenC`
357 mapCs bind_fv payload_bind_details `thenC`
359 -- Generate the info table and code
360 closureCodeBody NoStgBinderInfo
363 [] -- No args; it's a thunk
367 %************************************************************************
369 \subsection[code-for-closures]{The code for closures}
371 %************************************************************************
374 closureCodeBody :: StgBinderInfo
375 -> ClosureInfo -- Lots of information about this closure
376 -> CostCentre -- Optional cost centre attached to closure
382 There are two main cases for the code for closures. If there are {\em
383 no arguments}, then the closure is a thunk, and not in normal form.
384 So it should set up an update frame (if it is shared). Also, it has
385 no argument satisfaction check, so fast and slow entry-point labels
389 closureCodeBody binder_info closure_info cc [] body
390 = -- thunks cannot have a primitive type!
394 = case (closureType closure_info) of
395 Nothing -> (False, panic "debug")
396 Just (tc,_,_) -> (True, tc)
398 if has_tycon && isPrimTyCon tycon then
399 pprPanic "closureCodeBody:thunk:prim type!" (ppr PprDebug tycon)
402 getAbsC body_code `thenFC` \ body_absC ->
403 moduleName `thenFC` \ mod_name ->
405 absC (CClosureInfoAndCode closure_info body_absC Nothing
406 stdUpd (cl_descr mod_name)
407 (dataConLiveness closure_info))
409 cl_descr mod_name = closureDescription mod_name (closureId closure_info) [] body
411 body_addr = CLbl (entryLabelFromCI closure_info) CodePtrRep
412 body_code = profCtrC SLIT("ENT_THK") [] `thenC`
413 thunkWrapper closure_info (
414 -- We only enter cc after setting up update so that cc
415 -- of enclosing scope will be recorded in update frame
416 -- CAF/DICT functions will be subsumed by this enclosing cc
417 enterCostCentreCode closure_info cc IsThunk `thenC`
420 stdUpd = CLbl mkErrorStdEntryLabel CodePtrRep
423 If there is {\em at least one argument}, then this closure is in
424 normal form, so there is no need to set up an update frame. On the
425 other hand, we do have to check that there are enough args, and
426 perform an update if not!
428 The Macros for GrAnSim are produced at the beginning of the
429 argSatisfactionCheck (by calling fetchAndReschedule). There info if
430 Node points to closure is available. -- HWL
433 closureCodeBody binder_info closure_info cc all_args body
434 = getEntryConvention id lf_info
435 (map idPrimRep all_args) `thenFC` \ entry_conv ->
437 is_concurrent = opt_ForConcurrent
439 stg_arity = length all_args
441 -- Arg mapping for standard (slow) entry point; all args on stack
442 (spA_all_args, spB_all_args, all_bxd_w_offsets, all_ubxd_w_offsets)
444 0 0 -- Initial virtual SpA, SpB
448 -- Arg mapping for the fast entry point; as many args as poss in
449 -- registers; the rest on the stack
450 -- arg_regs are the registers used for arg passing
451 -- stk_args are the args which are passed on the stack
453 arg_regs = case entry_conv of
454 DirectEntry lbl arity regs -> regs
455 ViaNode | is_concurrent -> []
456 other -> panic "closureCodeBody:arg_regs"
458 num_arg_regs = length arg_regs
460 (reg_args, stk_args) = splitAt num_arg_regs all_args
462 (spA_stk_args, spB_stk_args, stk_bxd_w_offsets, stk_ubxd_w_offsets)
464 0 0 -- Initial virtual SpA, SpB
468 -- HWL; Note: empty list of live regs in slow entry code
469 -- Old version (reschedule combined with heap check);
470 -- see argSatisfactionCheck for new version
471 --slow_entry_code = forceHeapCheck [node] True slow_entry_code'
472 -- where node = VanillaReg PtrRep 1
473 --slow_entry_code = forceHeapCheck [] True slow_entry_code'
476 = profCtrC SLIT("ENT_FUN_STD") [] `thenC`
478 -- Bind args, and record expected position of stk ptrs
479 mapCs bindNewToAStack all_bxd_w_offsets `thenC`
480 mapCs bindNewToBStack all_ubxd_w_offsets `thenC`
481 setRealAndVirtualSps spA_all_args spB_all_args `thenC`
483 argSatisfactionCheck closure_info all_args `thenC`
485 -- OK, so there are enough args. Now we need to stuff as
486 -- many of them in registers as the fast-entry code
487 -- expects Note that the zipWith will give up when it hits
488 -- the end of arg_regs.
490 mapFCs getCAddrMode all_args `thenFC` \ stk_amodes ->
491 absC (mkAbstractCs (zipWith assign_to_reg arg_regs stk_amodes)) `thenC`
493 -- Now adjust real stack pointers
494 adjustRealSps spA_stk_args spB_stk_args `thenC`
496 absC (CFallThrough (CLbl fast_label CodePtrRep))
498 assign_to_reg reg_id amode = CAssign (CReg reg_id) amode
501 -- Old version (reschedule combined with heap check);
502 -- see argSatisfactionCheck for new version
503 -- fast_entry_code = forceHeapCheck [] True fast_entry_code'
506 = profCtrC SLIT("ENT_FUN_DIRECT") [
507 CLbl (mkRednCountsLabel id) PtrRep,
508 CString (_PK_ (showId PprDebug id)),
509 mkIntCLit stg_arity, -- total # of args
510 mkIntCLit spA_stk_args, -- # passed on A stk
511 mkIntCLit spB_stk_args, -- B stk (rest in regs)
512 CString (_PK_ (map (showTypeCategory . idType) all_args)),
513 CString (_PK_ (show_wrapper_name wrapper_maybe)),
514 CString (_PK_ (show_wrapper_arg_kinds wrapper_maybe))
517 -- Bind args to regs/stack as appropriate, and
518 -- record expected position of sps
519 bindArgsToRegs reg_args arg_regs `thenC`
520 mapCs bindNewToAStack stk_bxd_w_offsets `thenC`
521 mapCs bindNewToBStack stk_ubxd_w_offsets `thenC`
522 setRealAndVirtualSps spA_stk_args spB_stk_args `thenC`
524 -- Enter the closures cc, if required
525 enterCostCentreCode closure_info cc IsFunction `thenC`
528 funWrapper closure_info arg_regs (cgExpr body)
530 -- Make a labelled code-block for the slow and fast entry code
531 forkAbsC (if slow_code_needed then slow_entry_code else absC AbsCNop)
532 `thenFC` \ slow_abs_c ->
533 forkAbsC fast_entry_code `thenFC` \ fast_abs_c ->
534 moduleName `thenFC` \ mod_name ->
536 -- Now either construct the info table, or put the fast code in alone
537 -- (We never have slow code without an info table)
539 if info_table_needed then
540 CClosureInfoAndCode closure_info slow_abs_c (Just fast_abs_c)
541 stdUpd (cl_descr mod_name)
542 (dataConLiveness closure_info)
544 CCodeBlock fast_label fast_abs_c
547 lf_info = closureLFInfo closure_info
549 cl_descr mod_name = closureDescription mod_name id all_args body
551 -- Figure out what is needed and what isn't
552 slow_code_needed = slowFunEntryCodeRequired id binder_info
553 info_table_needed = funInfoTableRequired id binder_info lf_info
555 -- Manufacture labels
556 id = closureId closure_info
558 fast_label = fastLabelFromCI closure_info
560 stdUpd = CLbl mkErrorStdEntryLabel CodePtrRep
562 wrapper_maybe = get_ultimate_wrapper Nothing id
564 get_ultimate_wrapper deflt x -- walk all the way up a "wrapper chain"
565 = case (myWrapperMaybe x) of
567 Just xx -> get_ultimate_wrapper (Just xx) xx
569 show_wrapper_name Nothing = ""
570 show_wrapper_name (Just xx) = showId PprDebug xx
572 show_wrapper_arg_kinds Nothing = ""
573 show_wrapper_arg_kinds (Just xx)
574 = case (getWrapperArgTypeCategories (idType xx) (getIdStrictness xx)) of
579 For lexically scoped profiling we have to load the cost centre from
580 the closure entered, if the costs are not supposed to be inherited.
581 This is done immediately on entering the fast entry point.
583 Load current cost centre from closure, if not inherited.
584 Node is guaranteed to point to it, if profiling and not inherited.
587 data IsThunk = IsThunk | IsFunction -- Bool-like, local
592 enterCostCentreCode :: ClosureInfo -> CostCentre -> IsThunk -> Code
594 enterCostCentreCode closure_info cc is_thunk
595 = costCentresFlag `thenFC` \ profiling_on ->
596 if not profiling_on then
599 ASSERT(not (noCostCentreAttached cc))
601 if costsAreSubsumed cc then
602 --ASSERT(isToplevClosure closure_info)
603 --ASSERT(is_thunk == IsFunction)
604 (if isToplevClosure closure_info && is_thunk == IsFunction then \x->x else pprTrace "enterCostCenterCode:" (ppCat [ppr PprDebug (is_thunk == IsFunction){-, ppr PprDebug closure_info-}, ppStr (showCostCentre PprDebug False cc)])) $
605 costCentresC SLIT("ENTER_CC_FSUB") []
607 else if currentOrSubsumedCosts cc then
608 -- i.e. current; subsumed dealt with above
609 -- get CCC out of the closure, where we put it when we alloc'd
611 IsThunk -> costCentresC SLIT("ENTER_CC_TCL") [CReg node]
612 IsFunction -> costCentresC SLIT("ENTER_CC_FCL") [CReg node]
614 else if isCafCC cc && isToplevClosure closure_info then
615 ASSERT(is_thunk == IsThunk)
616 costCentresC SLIT("ENTER_CC_CAF") [mkCCostCentre cc]
618 else -- we've got a "real" cost centre right here in our hands...
620 IsThunk -> costCentresC SLIT("ENTER_CC_T") [mkCCostCentre cc]
621 IsFunction -> if isCafCC cc || isDictCC cc
622 then costCentresC SLIT("ENTER_CC_FCAF") [mkCCostCentre cc]
623 else costCentresC SLIT("ENTER_CC_FLOAD") [mkCCostCentre cc]
626 %************************************************************************
628 \subsubsection[pre-closure-code-stuff]{Pre-closure-code code}
630 %************************************************************************
632 The argument-satisfaction check code is placed after binding
633 the arguments to their stack locations. Hence, the virtual stack
634 pointer is pointing after all the args, and virtual offset 1 means
635 the base of frame and hence most distant arg. Hence
636 virtual offset 0 is just beyond the most distant argument; the
637 relative offset of this word tells how many words of arguments
641 argSatisfactionCheck :: ClosureInfo -> [Id] -> Code
643 argSatisfactionCheck closure_info [] = nopC
645 argSatisfactionCheck closure_info args
646 = -- safest way to determine which stack last arg will be on:
647 -- look up CAddrMode that last arg is bound to;
649 -- check isFollowableRep.
651 nodeMustPointToIt (closureLFInfo closure_info) `thenFC` \ node_points ->
654 emit_gran_macros = opt_GranMacros
658 -- absC (CMacroStmt GRAN_FETCH []) `thenC`
659 -- forceHeapCheck [] node_points (absC AbsCNop) `thenC`
662 then fetchAndReschedule [] node_points
663 else yield [] node_points
664 else absC AbsCNop) `thenC`
666 getCAddrMode (last args) `thenFC` \ last_amode ->
668 if (isFollowableRep (getAmodeRep last_amode)) then
669 getSpARelOffset 0 `thenFC` \ (SpARel spA off) ->
671 a_rel_int = spARelToInt spA off
672 a_rel_arg = mkIntCLit a_rel_int
674 ASSERT(a_rel_int /= 0)
676 absC (CMacroStmt ARGS_CHK_A [a_rel_arg])
678 absC (CMacroStmt ARGS_CHK_A_LOAD_NODE [a_rel_arg, set_Node_to_this])
680 getSpBRelOffset 0 `thenFC` \ (SpBRel spB off) ->
682 b_rel_int = spBRelToInt spB off
683 b_rel_arg = mkIntCLit b_rel_int
685 ASSERT(b_rel_int /= 0)
687 absC (CMacroStmt ARGS_CHK_B [b_rel_arg])
689 absC (CMacroStmt ARGS_CHK_B_LOAD_NODE [b_rel_arg, set_Node_to_this])
691 -- We must tell the arg-satis macro whether Node is pointing to
692 -- the closure or not. If it isn't so pointing, then we give to
693 -- the macro the (static) address of the closure.
695 set_Node_to_this = CLbl (closureLabelFromCI closure_info) PtrRep
698 %************************************************************************
700 \subsubsection[closure-code-wrappers]{Wrappers around closure code}
702 %************************************************************************
705 thunkWrapper:: ClosureInfo -> Code -> Code
706 thunkWrapper closure_info thunk_code
707 = -- Stack and heap overflow checks
708 nodeMustPointToIt (closureLFInfo closure_info) `thenFC` \ node_points ->
711 emit_gran_macros = opt_GranMacros
713 -- HWL: insert macros for GrAnSim; 2 versions depending on liveness of node
714 -- (we prefer fetchAndReschedule-style context switches to yield ones)
717 then fetchAndReschedule [] node_points
718 else yield [] node_points
719 else absC AbsCNop) `thenC`
721 stackCheck closure_info [] node_points ( -- stackCheck *encloses* the rest
723 -- heapCheck must be after stackCheck: if stchk fails
724 -- new stack space is allocated from the heap which
725 -- would violate any previous heapCheck
727 heapCheck [] node_points ( -- heapCheck *encloses* the rest
728 -- The "[]" says there are no live argument registers
730 -- Overwrite with black hole if necessary
731 blackHoleIt closure_info `thenC`
733 setupUpdate closure_info ( -- setupUpdate *encloses* the rest
735 -- Finally, do the business
739 funWrapper :: ClosureInfo -- Closure whose code body this is
740 -> [MagicId] -- List of argument registers (if any)
741 -> Code -- Body of function being compiled
743 funWrapper closure_info arg_regs fun_body
744 = -- Stack overflow check
745 nodeMustPointToIt (closureLFInfo closure_info) `thenFC` \ node_points ->
747 emit_gran_macros = opt_GranMacros
751 then yield arg_regs node_points
752 else absC AbsCNop) `thenC`
754 stackCheck closure_info arg_regs node_points (
755 -- stackCheck *encloses* the rest
757 heapCheck arg_regs node_points (
758 -- heapCheck *encloses* the rest
760 -- Finally, do the business
765 %************************************************************************
767 \subsubsubsection[overflow-checks]{Stack and heap overflow wrappers}
769 %************************************************************************
771 Assumption: virtual and real stack pointers are currently exactly aligned.
774 stackCheck :: ClosureInfo
775 -> [MagicId] -- Live registers
776 -> Bool -- Node required to point after check?
780 stackCheck closure_info regs node_reqd code
781 = getFinalStackHW (\ aHw -> \ bHw -> -- Both virtual stack offsets
783 getVirtSps `thenFC` \ (vSpA, vSpB) ->
785 let a_headroom_reqd = aHw - vSpA -- Virtual offsets are positive integers
786 b_headroom_reqd = bHw - vSpB
789 absC (if (a_headroom_reqd == 0 && b_headroom_reqd == 0) then
792 CMacroStmt STK_CHK [mkIntCLit liveness_mask,
793 mkIntCLit a_headroom_reqd,
794 mkIntCLit b_headroom_reqd,
797 mkIntCLit (if returns_prim_type then 1 else 0),
798 mkIntCLit (if node_reqd then 1 else 0)]
800 -- The test is *inside* the absC, to avoid black holes!
805 all_regs = if node_reqd then node:regs else regs
806 liveness_mask = mkLiveRegsMask all_regs
808 returns_prim_type = closureReturnsUnboxedType closure_info
811 %************************************************************************
813 \subsubsubsection[update-and-BHs]{Update and black-hole wrappers}
815 %************************************************************************
819 blackHoleIt :: ClosureInfo -> Code -- Only called for thunks
820 blackHoleIt closure_info
821 = noBlackHolingFlag `thenFC` \ no_black_holing ->
823 if (blackHoleOnEntry no_black_holing closure_info)
825 absC (if closureSingleEntry(closure_info) then
826 CMacroStmt UPD_BH_SINGLE_ENTRY [CReg node]
828 CMacroStmt UPD_BH_UPDATABLE [CReg node])
829 -- Node always points to it; see stg-details
835 setupUpdate :: ClosureInfo -> Code -> Code -- Only called for thunks
836 -- Nota Bene: this function does not change Node (even if it's a CAF),
837 -- so that the cost centre in the original closure can still be
838 -- extracted by a subsequent ENTER_CC_TCL
840 setupUpdate closure_info code
841 = if (closureUpdReqd closure_info) then
842 link_caf_if_needed `thenFC` \ update_closure ->
843 pushUpdateFrame update_closure vector code
845 profCtrC SLIT("UPDF_OMITTED") [] `thenC`
848 link_caf_if_needed :: FCode CAddrMode -- Returns amode for closure to be updated
850 = if not (isStaticClosure closure_info) then
854 -- First we must allocate a black hole, and link the
855 -- CAF onto the CAF list
857 -- Alloc black hole specifying CC_HDR(Node) as the cost centre
858 -- Hack Warning: Using a CLitLit to get CAddrMode !
860 use_cc = CLitLit SLIT("CC_HDR(R1.p)") PtrRep
863 allocDynClosure (blackHoleClosureInfo closure_info) use_cc blame_cc []
864 `thenFC` \ heap_offset ->
865 getHpRelOffset heap_offset `thenFC` \ hp_rel ->
866 let amode = CAddr hp_rel
868 absC (CMacroStmt UPD_CAF [CReg node, amode])
873 = case (closureType closure_info) of
874 Nothing -> CReg StdUpdRetVecReg
875 Just (spec_tycon, _, spec_datacons) ->
876 case (ctrlReturnConvAlg spec_tycon) of
877 UnvectoredReturn 1 ->
879 spec_data_con = head spec_datacons
880 only_tag = dataConTag spec_data_con
882 direct = case (dataReturnConvAlg spec_data_con) of
883 ReturnInRegs _ -> mkConUpdCodePtrVecLabel spec_tycon only_tag
884 ReturnInHeap -> mkStdUpdCodePtrVecLabel spec_tycon only_tag
886 vectored = mkStdUpdVecTblLabel spec_tycon
888 CUnVecLbl direct vectored
890 UnvectoredReturn _ -> CReg StdUpdRetVecReg
891 VectoredReturn _ -> CLbl (mkStdUpdVecTblLabel spec_tycon) DataPtrRep
894 %************************************************************************
896 \subsection[CgClosure-Description]{Profiling Closure Description.}
898 %************************************************************************
900 For "global" data constructors the description is simply occurrence
901 name of the data constructor itself (see \ref{CgConTbls-info-tables}).
903 Otherwise it is determind by @closureDescription@ from the let
907 closureDescription :: FAST_STRING -- Module
908 -> Id -- Id of closure binding
913 -- Not called for StgRhsCon which have global info tables built in
914 -- CgConTbls.lhs with a description generated from the data constructor
916 closureDescription mod_name name args body
917 = uppShow 0 (prettyToUn (
918 ppBesides [ppChar '<',
926 chooseDynCostCentres cc args fvs body
928 use_cc -- cost-centre we record in the object
929 = if currentOrSubsumedCosts cc
930 then CReg CurCostCentre
931 else mkCCostCentre cc
933 blame_cc -- cost-centre on whom we blame the allocation
934 = case (args, fvs, body) of
935 ([], [just1], StgApp (StgVarArg fun) [{-no args-}] _)
937 -> mkCCostCentre overheadCostCentre
940 -- if it's an utterly trivial RHS, then it must be
941 -- one introduced by boxHigherOrderArgs for profiling,
942 -- so we charge it to "OVERHEAD".