%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
-% $Id: CgTailCall.lhs,v 1.43 2005/06/21 10:44:41 simonmar Exp $
-%
-%********************************************************
-%* *
-\section[CgTailCall]{Tail calls: converting @StgApps@}
-%* *
-%********************************************************
+% Code generation for tail calls.
\begin{code}
module CgTailCall (
cgTailCall, performTailCall,
performReturn, performPrimReturn,
- emitKnownConReturnCode, emitAlgReturnCode,
returnUnboxedTuple, ccallReturnUnboxedTuple,
pushUnboxedTuple,
tailCallPrimOp,
#include "HsVersions.h"
import CgMonad
-import CgBindery ( getArgAmodes, getCgIdInfo, CgIdInfo, maybeLetNoEscape,
- idInfoToAmode, cgIdInfoId, cgIdInfoLF,
- cgIdInfoArgRep )
-import CgInfoTbls ( entryCode, emitDirectReturnInstr, dataConTagZ,
- emitVectoredReturnInstr, closureInfoPtr )
+import CgBindery
+import CgInfoTbls
import CgCallConv
-import CgStackery ( setRealSp, mkStkAmodes, adjustStackHW,
- getSpRelOffset )
-import CgHeapery ( setRealHp, getHpRelOffset )
-import CgUtils ( emitSimultaneously )
+import CgStackery
+import CgHeapery
+import CgUtils
import CgTicky
import ClosureInfo
-import SMRep ( CgRep, isVoidArg, separateByPtrFollowness )
+import SMRep
import Cmm
import CmmUtils
-import CLabel ( CLabel, mkRtsPrimOpLabel, mkSeqInfoLabel )
-import Type ( isUnLiftedType )
-import Id ( Id, idName, idUnique, idType )
-import DataCon ( DataCon, dataConTyCon )
-import StgSyn ( StgArg )
-import TyCon ( TyCon )
-import PrimOp ( PrimOp )
+import CLabel
+import Type
+import Id
+import StgSyn
+import PrimOp
import Outputable
-import Monad ( when )
+import Control.Monad
-----------------------------------------------------------------------------
-- Tail Calls
opt_node_asst | nodeMustPointToIt lf_info = node_asst
| otherwise = noStmts
; EndOfBlockInfo sp _ <- getEndOfBlockInfo
- ; hmods <- getHomeModules
+ ; this_pkg <- getThisPackage
- ; case (getCallMethod hmods fun_name lf_info (length arg_amodes)) of
+ ; case (getCallMethod this_pkg fun_name lf_info (length arg_amodes)) of
-- Node must always point to things we enter
EnterIt -> do
-- As with any return, Node must point to it.
ReturnIt -> do
{ emitSimultaneously (node_asst `plusStmts` pending_assts)
- ; doFinalJump sp False emitDirectReturnInstr }
+ ; doFinalJump sp False emitReturnInstr }
-- A real constructor. Don't bother entering it,
-- just do the right sort of return instead.
-- As with any return, Node must point to it.
ReturnCon con -> do
{ emitSimultaneously (node_asst `plusStmts` pending_assts)
- ; doFinalJump sp False (emitKnownConReturnCode con) }
+ ; doFinalJump sp False emitReturnInstr }
JumpToIt lbl -> do
{ emitSimultaneously (opt_node_asst `plusStmts` pending_assts)
-- and do the jump
; jump_code }
--- -----------------------------------------------------------------------------
+-- ----------------------------------------------------------------------------
-- A general return (just a special case of doFinalJump, above)
-performReturn :: Code -- The code to execute to actually do the return
+performReturn :: Code -- The code to execute to actually do the return
-> Code
performReturn finish_code
= do { EndOfBlockInfo args_sp sequel <- getEndOfBlockInfo
; doFinalJump args_sp False{-not a LNE-} finish_code }
--- -----------------------------------------------------------------------------
+-- ----------------------------------------------------------------------------
-- Primitive Returns
-- Just load the return value into the right register, and return.
performPrimReturn rep amode
= do { whenC (not (isVoidArg rep))
(stmtC (CmmAssign ret_reg amode))
- ; performReturn emitDirectReturnInstr }
+ ; performReturn emitReturnInstr }
where
ret_reg = dataReturnConvPrim rep
--- -----------------------------------------------------------------------------
--- Algebraic constructor returns
-
--- Constructor is built on the heap; Node is set.
--- All that remains is to do the right sort of jump.
-
-emitKnownConReturnCode :: DataCon -> Code
-emitKnownConReturnCode con
- = emitAlgReturnCode (dataConTyCon con)
- (CmmLit (mkIntCLit (dataConTagZ con)))
- -- emitAlgReturnCode requires zero-indexed tag
-
-emitAlgReturnCode :: TyCon -> CmmExpr -> Code
--- emitAlgReturnCode is used both by emitKnownConReturnCode,
--- and by by PrimOps that return enumerated types (i.e.
--- all the comparison operators).
-emitAlgReturnCode tycon tag
- = do { case ctrlReturnConvAlg tycon of
- VectoredReturn fam_sz -> do { tickyVectoredReturn fam_sz
- ; emitVectoredReturnInstr tag }
- UnvectoredReturn _ -> emitDirectReturnInstr
- }
-
-
-- ---------------------------------------------------------------------------
-- Unboxed tuple returns
; tickyUnboxedTupleReturn (length amodes)
; (final_sp, assts) <- pushUnboxedTuple args_sp amodes
; emitSimultaneously assts
- ; doFinalJump final_sp False{-not a LNE-} emitDirectReturnInstr }
+ ; doFinalJump final_sp False{-not a LNE-} emitReturnInstr }
pushUnboxedTuple :: VirtualSpOffset -- Sp at which to start pushing
-> [(CgRep, CmmExpr)] -- amodes of the components
pushReturnAddress :: EndOfBlockInfo -> Code
-pushReturnAddress (EndOfBlockInfo args_sp sequel@(CaseAlts lbl _ _ False))
+pushReturnAddress (EndOfBlockInfo args_sp sequel@(CaseAlts lbl _ _))
= do { sp_rel <- getSpRelOffset args_sp
; stmtC (CmmStore sp_rel (mkLblExpr lbl)) }
--- For a polymorphic case, we have two return addresses to push: the case
--- return, and stg_seq_frame_info which turns a possible vectored return
--- into a direct one.
-pushReturnAddress (EndOfBlockInfo args_sp sequel@(CaseAlts lbl _ _ True))
- = do { sp_rel <- getSpRelOffset (args_sp-1)
- ; stmtC (CmmStore sp_rel (mkLblExpr lbl))
- ; sp_rel <- getSpRelOffset args_sp
- ; stmtC (CmmStore sp_rel (CmmLit (CmmLabel mkSeqInfoLabel))) }
-
pushReturnAddress _ = nopC
-- -----------------------------------------------------------------------------
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