Remove vectored returns.

We recently discovered that they aren't a win any more, and just cost
code size.

compiler/cmm/CLabel.hs

@@ -48,7 +48,6 @@ module CLabel (
 	mkSplitMarkerLabel,
 	mkDirty_MUT_VAR_Label,
 	mkUpdInfoLabel,
-	mkSeqInfoLabel,
 	mkIndStaticInfoLabel,
         mkMainCapabilityLabel,
 	mkMAP_FROZEN_infoLabel,
@@ -358,7 +357,6 @@ mkPlainModuleInitLabel this_pkg mod
 mkSplitMarkerLabel		= RtsLabel (RtsCode SLIT("__stg_split_marker"))
 mkDirty_MUT_VAR_Label		= RtsLabel (RtsCode SLIT("dirty_MUT_VAR"))
 mkUpdInfoLabel			= RtsLabel (RtsInfo SLIT("stg_upd_frame"))
-mkSeqInfoLabel			= RtsLabel (RtsInfo SLIT("stg_seq_frame"))
 mkIndStaticInfoLabel		= RtsLabel (RtsInfo SLIT("stg_IND_STATIC"))
 mkMainCapabilityLabel		= RtsLabel (RtsData SLIT("MainCapability"))
 mkMAP_FROZEN_infoLabel		= RtsLabel (RtsInfo SLIT("stg_MUT_ARR_PTRS_FROZEN0"))

compiler/cmm/CmmParse.y

@@ -230,12 +230,8 @@ info	:: { ExtFCode (CLabel, [CmmLit],[CmmLit]) }
 		-- selector, closure type, description, type
 		{ basicInfo $3 (mkIntCLit (fromIntegral $5)) 0 $7 $9 $11 }
 
-	| 'INFO_TABLE_RET' '(' NAME ',' INT ',' INT ',' INT maybe_vec ')'
-		{ retInfo $3 $5 $7 $9 $10 }
-
-maybe_vec :: { [CmmLit] }
-	: {- empty -}			{ [] }
-	| ',' NAME maybe_vec		{ CmmLabel (mkRtsCodeLabelFS $2) : $3 }
+	| 'INFO_TABLE_RET' '(' NAME ',' INT ',' INT ',' INT ')'
+		{ retInfo $3 $5 $7 $9 }
 
 body	:: { ExtCode }
 	: {- empty -}			{ return () }
@@ -473,8 +469,7 @@ exprMacros = listToUFM [
   ( FSLIT("GET_FUN_INFO"), \ [x] -> funInfoTable (closureInfoPtr x) ),
   ( FSLIT("INFO_TYPE"),    \ [x] -> infoTableClosureType x ),
   ( FSLIT("INFO_PTRS"),    \ [x] -> infoTablePtrs x ),
-  ( FSLIT("INFO_NPTRS"),   \ [x] -> infoTableNonPtrs x ),
-  ( FSLIT("RET_VEC"),      \ [info, conZ] -> retVec info conZ )
+  ( FSLIT("INFO_NPTRS"),   \ [x] -> infoTableNonPtrs x )
   ]
 
 -- we understand a subset of C-- primitives:
@@ -709,11 +704,11 @@ forkLabelledCodeEC ec = do
   stmts <- getCgStmtsEC ec
   code (forkCgStmts stmts)
 
-retInfo name size live_bits cl_type vector = do
+retInfo name size live_bits cl_type = do
   let liveness = smallLiveness (fromIntegral size) (fromIntegral live_bits)
       info_lbl = mkRtsRetInfoLabelFS name
       (info1,info2) = mkRetInfoTable info_lbl liveness NoC_SRT 
-				(fromIntegral cl_type) vector
+				(fromIntegral cl_type)
   return (info_lbl, info1, info2)
 
 stdInfo name ptrs nptrs srt_bitmap cl_type desc_str ty_str =

compiler/codeGen/CgCallConv.hs

@@ -25,8 +25,6 @@ module CgCallConv (
 	constructSlowCall, slowArgs, slowCallPattern,
 
 	-- Returns
-	CtrlReturnConvention(..),
-	ctrlReturnConvAlg,
 	dataReturnConvPrim,
 	getSequelAmode
     ) where
@@ -48,7 +46,6 @@ import CmmUtils
 import Maybes
 import Id
 import Name
-import TyCon
 import Bitmap
 import Util
 import StaticFlags
@@ -215,10 +212,6 @@ constructSlowCall amodes
     stg_ap_pat = mkRtsApFastLabel arg_pat
     (arg_pat, these, rest) = matchSlowPattern amodes
 
-enterRtsRetLabel arg_pat
-  | tablesNextToCode = mkRtsRetInfoLabel arg_pat
-  | otherwise        = mkRtsRetLabel arg_pat
-
 -- | 'slowArgs' takes a list of function arguments and prepares them for
 -- pushing on the stack for "extra" arguments to a function which requires
 -- fewer arguments than we currently have.
@@ -257,26 +250,6 @@ slowCallPattern _  = panic "CgStackery.slowCallPattern"
 --
 -------------------------------------------------------------------------
 
--- A @CtrlReturnConvention@ says how {\em control} is returned.
-
-data CtrlReturnConvention
-  = VectoredReturn	Int	-- size of the vector table (family size)
-  | UnvectoredReturn    Int 	-- family size
-
-ctrlReturnConvAlg :: TyCon -> CtrlReturnConvention
-ctrlReturnConvAlg tycon
-  = case (tyConFamilySize tycon) of
-      size -> -- we're supposed to know...
-	if (size > (1::Int) && size <= mAX_FAMILY_SIZE_FOR_VEC_RETURNS) then
-	    VectoredReturn size
-	else
-	    UnvectoredReturn size	
-  -- NB: unvectored returns Include size 0 (no constructors), so that
-  --     the following perverse code compiles (it crashed GHC in 5.02)
-  -- 	    data T1
-  --	    data T2 = T2 !T1 Int
-  --     The only value of type T1 is bottom, which never returns anyway.
-
 dataReturnConvPrim :: CgRep -> CmmReg
 dataReturnConvPrim PtrArg    = CmmGlobal (VanillaReg 1)
 dataReturnConvPrim NonPtrArg = CmmGlobal (VanillaReg 1)
@@ -287,7 +260,7 @@ dataReturnConvPrim VoidArg   = panic "dataReturnConvPrim: void"
 
 
 -- getSequelAmode returns an amode which refers to an info table.  The info
--- table will always be of the RET(_VEC)?_(BIG|SMALL) kind.  We're careful
+-- table will always be of the RET_(BIG|SMALL) kind.  We're careful
 -- not to handle real code pointers, just in case we're compiling for 
 -- an unregisterised/untailcallish architecture, where info pointers and
 -- code pointers aren't the same.
@@ -304,9 +277,8 @@ getSequelAmode
 	    OnStack -> do { sp_rel <- getSpRelOffset virt_sp
 			  ; returnFC (CmmLoad sp_rel wordRep) }
 
-	    UpdateCode 	           -> returnFC (CmmLit (CmmLabel mkUpdInfoLabel))
-	    CaseAlts lbl _ _ True  -> returnFC (CmmLit (CmmLabel mkSeqInfoLabel))
-	    CaseAlts lbl _ _ False -> returnFC (CmmLit (CmmLabel lbl))
+	    UpdateCode 	      -> returnFC (CmmLit (CmmLabel mkUpdInfoLabel))
+	    CaseAlts lbl _ _  -> returnFC (CmmLit (CmmLabel lbl))
 	}
 
 -------------------------------------------------------------------------

compiler/codeGen/CgCase.lhs

@@ -197,7 +197,7 @@ cgCase (StgApp fun args)
 			(do { deAllocStackTop retAddrSizeW
 			    ; cgEvalAlts maybe_cc_slot bndr srt alt_type alts })
 
-	; setEndOfBlockInfo (maybeReserveSeqFrame alt_type scrut_eob_info)
+	; setEndOfBlockInfo scrut_eob_info
 			    (performTailCall fun_info arg_amodes save_assts) }
 \end{code}
 
@@ -234,8 +234,7 @@ cgCase expr live_in_whole_case live_in_alts bndr srt alt_type alts
 			   (do	{ deAllocStackTop retAddrSizeW
 				; cgEvalAlts maybe_cc_slot bndr srt alt_type alts })
 
-	; setEndOfBlockInfo (maybeReserveSeqFrame alt_type scrut_eob_info)
-			    (cgExpr expr)
+	; setEndOfBlockInfo scrut_eob_info (cgExpr expr)
     }
 \end{code}
 
@@ -265,13 +264,6 @@ consequence of this is that activation records on the stack don't
 follow the layout of closures when we're profiling.  The CCS could be
 anywhere within the record).
 
-\begin{code}
-maybeReserveSeqFrame PolyAlt (EndOfBlockInfo args_sp (CaseAlts amode stuff bndr _))
-   = EndOfBlockInfo (args_sp + retAddrSizeW) (CaseAlts amode stuff bndr True)
-maybeReserveSeqFrame other scrut_eob_info = scrut_eob_info
-\end{code}
-
-
 %************************************************************************
 %*									*
 		Inline primops
@@ -380,8 +372,8 @@ cgEvalAlts cc_slot bndr srt alt_type@(PrimAlt tycon) alts
 		; restoreCurrentCostCentre cc_slot True
 		; cgPrimAlts GCMayHappen alt_type reg alts }
 
-	; lbl <- emitDirectReturnTarget (idName bndr) abs_c srt
-	; returnFC (CaseAlts lbl Nothing bndr False) }
+	; lbl <- emitReturnTarget (idName bndr) abs_c srt
+	; returnFC (CaseAlts lbl Nothing bndr) }
 
 cgEvalAlts cc_slot bndr srt (UbxTupAlt _) [(con,args,_,rhs)]
   =	-- Unboxed tuple case
@@ -392,7 +384,7 @@ cgEvalAlts cc_slot bndr srt (UbxTupAlt _) [(con,args,_,rhs)]
     ASSERT2( case con of { DataAlt _ -> True; other -> False },
 	     text "cgEvalAlts: dodgy case of unboxed tuple type" )
     do	{ 	-- forkAbsC for the RHS, so that the envt is
-		-- not changed for the emitDirectReturn call
+		-- not changed for the emitReturn call
 	  abs_c <- forkProc $ do 
 		{ (live_regs, ptrs, nptrs, _) <- bindUnboxedTupleComponents args
 			-- Restore the CC *after* binding the tuple components, 
@@ -402,8 +394,8 @@ cgEvalAlts cc_slot bndr srt (UbxTupAlt _) [(con,args,_,rhs)]
 			-- and finally the code for the alternative
 		; unbxTupleHeapCheck live_regs ptrs nptrs noStmts
 				     (cgExpr rhs) }
-	; lbl <- emitDirectReturnTarget (idName bndr) abs_c srt
-	; returnFC (CaseAlts lbl Nothing bndr False) }
+	; lbl <- emitReturnTarget (idName bndr) abs_c srt
+	; returnFC (CaseAlts lbl Nothing bndr) }
 
 cgEvalAlts cc_slot bndr srt alt_type alts
   = 	-- Algebraic and polymorphic case
@@ -422,13 +414,13 @@ cgEvalAlts cc_slot bndr srt alt_type alts
 	; (alts, mb_deflt) <- cgAlgAlts GCMayHappen cc_slot alt_type alts
 
 	; (lbl, branches) <- emitAlgReturnTarget (idName bndr) 
-				alts mb_deflt srt ret_conv
+				alts mb_deflt srt fam_sz
 
-	; returnFC (CaseAlts lbl branches bndr False) }
+	; returnFC (CaseAlts lbl branches bndr) }
   where
-    ret_conv = case alt_type of
-    		AlgAlt tc -> ctrlReturnConvAlg tc
-    		PolyAlt   -> UnvectoredReturn 0
+    fam_sz = case alt_type of
+    		AlgAlt tc -> tyConFamilySize tc
+    		PolyAlt   -> 0
 \end{code}
 
 

compiler/codeGen/CgCon.lhs

@@ -295,7 +295,7 @@ cgReturnDataCon con amodes
   = ASSERT( amodes `lengthIs` dataConRepArity con )
     do	{ EndOfBlockInfo _ sequel <- getEndOfBlockInfo
 	; case sequel of
-	    CaseAlts _ (Just (alts, deflt_lbl)) bndr _ 
+	    CaseAlts _ (Just (alts, deflt_lbl)) bndr
 	      ->    -- Ho! We know the constructor so we can
 		    -- go straight to the right alternative
 		 case assocMaybe alts (dataConTagZ con) of {
@@ -317,7 +317,7 @@ cgReturnDataCon con amodes
     
 	    other_sequel	-- The usual case
 	      | isUnboxedTupleCon con -> returnUnboxedTuple amodes
-              | otherwise -> build_it_then (emitKnownConReturnCode con)
+              | otherwise -> build_it_then emitReturnInstr
 	}
   where
     jump_to lbl = stmtC (CmmJump (CmmLit lbl) [])
@@ -434,14 +434,12 @@ cgDataCon data_con
 	    body_code = do { 	
 			-- NB: We don't set CC when entering data (WDP 94/06)
 			     tickyReturnOldCon (length arg_things)
-			   ; performReturn (emitKnownConReturnCode data_con) }
+			   ; performReturn emitReturnInstr }
 				-- noStmts: Ptr to thing already in Node
 
 	; whenC (not (isNullaryRepDataCon data_con))
 	 	(emit_info dyn_cl_info tickyEnterDynCon)
 
 		-- Dynamic-Closure first, to reduce forward references
 	; emit_info static_cl_info tickyEnterStaticCon }
-
-  where
 \end{code}

compiler/codeGen/CgExpr.lhs

@@ -141,7 +141,7 @@ cgExpr (StgOpApp (StgPrimOp TagToEnumOp) [arg] res_ty)
 					-- so save in a temp if non-trivial
 	; this_pkg <- getThisPackage
 	; stmtC (CmmAssign nodeReg (tagToClosure this_pkg tycon amode'))
-	; performReturn (emitAlgReturnCode tycon amode') }
+	; performReturn emitReturnInstr }
    where
 	  -- If you're reading this code in the attempt to figure
 	  -- out why the compiler panic'ed here, it is probably because
@@ -157,12 +157,12 @@ cgExpr x@(StgOpApp op@(StgPrimOp primop) args res_ty)
 
   | ReturnsPrim VoidRep <- result_info
 	= do cgPrimOp [] primop args emptyVarSet
-	     performReturn emitDirectReturnInstr
+	     performReturn emitReturnInstr
 
   | ReturnsPrim rep <- result_info
 	= do cgPrimOp [dataReturnConvPrim (primRepToCgRep rep)] 
 			primop args emptyVarSet
-	     performReturn emitDirectReturnInstr
+	     performReturn emitReturnInstr
 
   | ReturnsAlg tycon <- result_info, isUnboxedTupleTyCon tycon
 	= do (reps, regs, _hints) <- newUnboxedTupleRegs res_ty
@@ -175,7 +175,7 @@ cgExpr x@(StgOpApp op@(StgPrimOp primop) args res_ty)
 	     this_pkg <- getThisPackage
 	     cgPrimOp [tag_reg] primop args emptyVarSet
 	     stmtC (CmmAssign nodeReg (tagToClosure this_pkg tycon (CmmReg tag_reg)))
-	     performReturn (emitAlgReturnCode tycon (CmmReg tag_reg))
+	     performReturn emitReturnInstr
   where
 	result_info = getPrimOpResultInfo primop
 \end{code}