%
% (c) The GRASP/AQUA Project, Glasgow University, 1993-1998
%
-% $Id: CgLetNoEscape.lhs,v 1.19 2002/12/11 15:36:26 simonmar Exp $
+% $Id: CgLetNoEscape.lhs,v 1.25 2004/08/13 13:06:03 simonmar Exp $
%
%********************************************************
%* *
import StgSyn
import CgMonad
-import AbsCSyn
-import CgBindery ( letNoEscapeIdInfo, bindArgsToRegs,
- bindNewToStack, buildContLivenessMask, CgIdInfo,
- nukeDeadBindings
- )
+import CgBindery ( CgIdInfo, letNoEscapeIdInfo, nukeDeadBindings )
+import CgCase ( restoreCurrentCostCentre )
+import CgCon ( bindUnboxedTupleComponents )
import CgHeapery ( unbxTupleHeapCheck )
-import CgRetConv ( assignRegs )
-import CgStackery ( mkVirtStkOffsets,
- allocStackTop, deAllocStackTop, freeStackSlots )
-import CgUsages ( setRealAndVirtualSp, getRealSp, getSpRelOffset )
+import CgInfoTbls ( emitDirectReturnTarget )
+import CgStackery ( allocStackTop, deAllocStackTop, getSpRelOffset )
+import Cmm ( CmmStmt(..) )
+import CmmUtils ( mkLblExpr, oneStmt )
import CLabel ( mkReturnInfoLabel )
import ClosureInfo ( mkLFLetNoEscape )
import CostCentre ( CostCentreStack )
-import Name ( getName )
-import Id ( idPrimRep, Id )
+import Id ( Id, idName )
import Var ( idUnique )
-import PrimRep ( PrimRep(..), retPrimRepSize, isFollowableRep )
+import SMRep ( retAddrSizeW )
import BasicTypes ( RecFlag(..) )
-import Unique ( Unique )
-import Util ( splitAtList )
-
-import List ( partition )
+import Outputable
\end{code}
%************************************************************************
-- ToDo: deal with the cost-centre issues
cgLetNoEscapeClosure
- binder cc binder_info srt full_live_in_rhss
+ bndr cc binder_info srt full_live_in_rhss
rhs_eob_info cc_slot rec args body
= let
arity = length args
lf_info = mkLFLetNoEscape arity
- uniq = idUnique binder
in
-
-- saveVolatileVarsAndRegs done earlier in cgExpr.
- forkEvalHelp
- rhs_eob_info
+ do { (vSp, _) <- forkEvalHelp rhs_eob_info
+
+ (do { allocStackTop retAddrSizeW
+ ; nukeDeadBindings full_live_in_rhss })
- (allocStackTop retPrimRepSize `thenFC` \_ ->
- nukeDeadBindings full_live_in_rhss)
+ (do { deAllocStackTop retAddrSizeW
+ ; abs_c <- forkProc $ cgLetNoEscapeBody bndr cc
+ cc_slot args body
- (deAllocStackTop retPrimRepSize `thenFC` \_ ->
- buildContLivenessMask (getName binder) `thenFC` \ liveness ->
- forkAbsC (cgLetNoEscapeBody binder cc args body uniq)
- `thenFC` \ code ->
- getSRTInfo srt `thenFC` \ srt_info ->
- absC (CRetDirect uniq code srt_info liveness)
- `thenC` returnFC ())
- `thenFC` \ (vSp, _) ->
+ -- Ignore the label that comes back from
+ -- mkRetDirectTarget. It must be conjured up elswhere
+ ; emitDirectReturnTarget (idName bndr) abs_c srt
+ ; return () })
- returnFC (binder, letNoEscapeIdInfo binder vSp lf_info)
+ ; returnFC (bndr, letNoEscapeIdInfo bndr vSp lf_info) }
\end{code}
\begin{code}
-cgLetNoEscapeBody :: Id
+cgLetNoEscapeBody :: Id -- Name of the joint point
-> CostCentreStack
+ -> Maybe VirtualSpOffset
-> [Id] -- Args
-> StgExpr -- Body
- -> Unique -- Unique for entry label
-> Code
-cgLetNoEscapeBody binder cc all_args body uniq
- =
- -- this is where the stack frame lives:
- getRealSp `thenFC` \sp ->
-
- -- This is very much like bindUnboxedTupleComponents (ToDo)
- let
- arg_kinds = map idPrimRep all_args
- (arg_regs, _) = assignRegs [{-nothing live-}] arg_kinds
- (reg_args, stk_args) = splitAtList arg_regs all_args
-
- -- separate the rest of the args into pointers and non-pointers
- ( ptr_args, nptr_args ) =
- partition (isFollowableRep . idPrimRep) stk_args
+cgLetNoEscapeBody bndr cc cc_slot all_args body = do
+ { (arg_regs, ptrs, nptrs, ret_slot) <- bindUnboxedTupleComponents all_args
- (ptr_sp, ptr_offsets) = mkVirtStkOffsets sp idPrimRep ptr_args
- (nptr_sp, nptr_offsets) = mkVirtStkOffsets ptr_sp idPrimRep nptr_args
-
- ptrs = ptr_sp - sp
- nptrs = nptr_sp - ptr_sp
- in
-
- -- Bind args to appropriate regs/stk locns
- bindArgsToRegs reg_args arg_regs `thenC`
- mapCs bindNewToStack ptr_offsets `thenC`
- mapCs bindNewToStack nptr_offsets `thenC`
-
- setRealAndVirtualSp nptr_sp `thenC`
-
- -- free up the stack slots containing the return address
- -- (frame header itbl). c.f. CgCase.cgUnboxedTupleAlt.
- freeStackSlots [sp] `thenC`
+ -- restore the saved cost centre. BUT: we must not free the stack slot
+ -- containing the cost centre, because it might be needed for a
+ -- recursive call to this let-no-escape.
+ ; restoreCurrentCostCentre cc_slot False{-don't free-}
-- Enter the closures cc, if required
- --enterCostCentreCode closure_info cc IsFunction `thenC`
+ ; -- enterCostCentreCode closure_info cc IsFunction
+
+ -- The "return address" slot doesn't have a return address in it;
+ -- but the heap-check needs it filled in if the heap-check fails.
+ -- So we pass code to fill it in to the heap-check macro
+ ; sp_rel <- getSpRelOffset ret_slot
- -- fill in the frame header only if we fail a heap check:
- -- otherwise it isn't needed.
- getSpRelOffset sp `thenFC` \sp_rel ->
- let lbl = mkReturnInfoLabel uniq
- frame_hdr_asst = CAssign (CVal sp_rel RetRep) (CLbl lbl RetRep)
- in
+ ; let lbl = mkReturnInfoLabel (idUnique bndr)
+ frame_hdr_asst = oneStmt (CmmStore sp_rel (mkLblExpr lbl))
-- Do heap check [ToDo: omit for non-recursive case by recording in
-- in envt and absorbing at call site]
- unbxTupleHeapCheck arg_regs ptrs nptrs frame_hdr_asst (
- cgExpr body
- )
+ ; unbxTupleHeapCheck arg_regs ptrs nptrs frame_hdr_asst
+ (cgExpr body)
+ }
\end{code}
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