X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FcodeGen%2FCgUpdate.lhs;h=33883a09abfa76f6bf73eff168b85826f1a2a60f;hb=f279803f7a5eb9b9fb7720e96b0ebbb2df65ee4f;hp=5c0accd6920f3f167e04cf6b3c5d7973c2ed8b72;hpb=7a3bd641457666e10d0a47be9f22762e03defbf0;p=ghc-hetmet.git

diff --git a/ghc/compiler/codeGen/CgUpdate.lhs b/ghc/compiler/codeGen/CgUpdate.lhs
index 5c0accd..33883a0 100644
--- a/ghc/compiler/codeGen/CgUpdate.lhs
+++ b/ghc/compiler/codeGen/CgUpdate.lhs
@@ -1,22 +1,19 @@
 %
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
 \section[CgUpdate]{Manipulating update frames}
 
 \begin{code}
-#include "HsVersions.h"
-
-module CgUpdate ( pushUpdateFrame ) where
+module CgUpdate ( pushUpdateFrame, reserveSeqFrame, pushSeqFrame ) where
 
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
 
 import CgMonad
 import AbsCSyn
 
-import Constants	( sTD_UF_SIZE, sCC_STD_UF_SIZE )
-import CgStackery	( allocUpdateFrame )
-import CmdLineOpts	( opt_SccProfilingOn )
-import Util		( assertPanic )
+import CgStackery	( allocStackTop, updateFrameSize, seqFrameSize )
+import CgUsages		( getVirtSp, getSpRelOffset )
+import Panic		( assertPanic )
 \end{code}
 
 
@@ -35,46 +32,49 @@ are guaranteed to be nicely aligned with the top of stack.
 to reflect the frame pushed.
 
 \begin{code}
-pushUpdateFrame :: CAddrMode -> CAddrMode -> Code -> Code
+pushUpdateFrame :: CAddrMode -> Code -> Code
 
-pushUpdateFrame updatee vector code
-  = let
-	profiling_on = opt_SccProfilingOn
-
-	-- frame_size *includes* the return address
-	frame_size = if profiling_on
-		     then sCC_STD_UF_SIZE
-		     else sTD_UF_SIZE
-    in
+pushUpdateFrame updatee code
+  = 
+#ifdef DEBUG
     getEndOfBlockInfo 	    	    	`thenFC` \ eob_info ->
-    ASSERT(case eob_info of { EndOfBlockInfo _ _ InRetReg -> True; _ -> False})
-    allocUpdateFrame frame_size vector (\ _ ->
+    ASSERT(case eob_info of { EndOfBlockInfo _ (OnStack _) -> True; 
+			      _ -> False})
+#endif
+
+    allocStackTop updateFrameSize	`thenFC` \ _ ->
+    getVirtSp				`thenFC` \ vsp ->
+
+    setEndOfBlockInfo (EndOfBlockInfo vsp UpdateCode) (
 
 		-- Emit the push macro
-	    absC (CMacroStmt PUSH_STD_UPD_FRAME [
+	    absC (CMacroStmt PUSH_UPD_FRAME [
 			updatee,
-			int_CLit0, 	-- Known to be zero because we have just
-			int_CLit0	-- entered a thunk
+			int_CLit0  -- we just entered a closure, so must be zero
 	    ])
 	    `thenC` code
     )
 
 int_CLit0 = mkIntCLit 0 -- out here to avoid pushUpdateFrame CAF (sigh)
+\end{code}
+
+We push a SEQ frame just before evaluating the scrutinee of a case, if
+the scrutinee has a polymorphic or function type.  The SEQ frame acts
+as a barrier in case the scrutinee evaluates to a partial application.
 
-{- ---------------------
-    What actually happens is something like this; but it got macro-ised
-
-  = pushOnBStack (CReg CurCostCentre)			`thenFC` \ _ ->
-    pushOnBStack (CReg SuA)				`thenFC` \ _ ->
-    pushOnBStack (CReg SuB)				`thenFC` \ _ ->
-    pushOnBStack updatee				`thenFC` \ _ ->
-    pushOnBStack (CLabel sTD_UPD_RET_VEC_LABEL CodePtrRep) `thenFC` \ _ ->
-
-	-- MAKE SuA, SuB POINT TO TOP OF A,B STACKS
-	-- Remember, SpB hasn't yet been incremented to account for the
-	-- 4-word update frame which has been pushed.
-	-- This code seems crude, but effective...
-    absC (AbsCStmts (CAssign (CReg SuA) (CReg SpA))
-		    (CAssign (CReg SuB) (CAddr (SpBRel 0 4))))
--------------------------- -}
+reserveSeqFrame takes the EndOfBlockInfo for the case expression and
+updates the sequel to a SeqFrame, reserving room for the frame at
+args_sp.  When the scrutinee comes around to pushing a return address,
+it will also push the SEQ frame, using pushSeqFrame.
+
+\begin{code}
+reserveSeqFrame :: EndOfBlockInfo -> EndOfBlockInfo
+reserveSeqFrame (EndOfBlockInfo args_sp (CaseAlts amode stuff)) 
+  = EndOfBlockInfo (args_sp + seqFrameSize) (SeqFrame amode stuff)
+
+pushSeqFrame :: VirtualSpOffset -> FCode VirtualSpOffset
+pushSeqFrame args_sp
+  = getSpRelOffset args_sp  `thenFC` \ sp_rel ->
+    absC (CMacroStmt PUSH_SEQ_FRAME [CAddr sp_rel]) `thenC`
+    returnFC (args_sp - seqFrameSize)
 \end{code}