From 9736b6072412fa3498ce8a89d58aaafd07bc2358 Mon Sep 17 00:00:00 2001
From: sof <unknown>
Date: Fri, 14 Mar 1997 05:00:47 +0000
Subject: [PATCH] [project @ 1997-03-14 05:00:47 by sof] Stk underflow fix
(HWL)
---
ghc/runtime/main/StgThreads.lhc | 47 ++++++++++++++++++++++++++++++++-
1 file changed, 46 insertions(+), 1 deletion(-)
diff --git a/ghc/runtime/main/StgThreads.lhc b/ghc/runtime/main/StgThreads.lhc
index c75eaaf44295..0bff4de676d0 100644
--- a/ghc/runtime/main/StgThreads.lhc
+++ b/ghc/runtime/main/StgThreads.lhc
@@ -356,7 +356,7 @@ DO_RETURN_TEMPLATE(UnderflowVect7, ((P_)RetReg)[RVREL(7)])
DO_RETURN_TEMPLATE(StackUnderflowEnterNode, EnterNodeCode)
-#else
+#else /* PAR */
\end{code}
@@ -436,6 +436,9 @@ STGFUN(PrimUnderflow)
* because R2 is dead, and R1 points to a PAP. Only R1 is live.
*/
+#if 0
+
+/* old version of the code */
STGFUN(StackUnderflowEnterNode)
{
FB_
@@ -445,8 +448,50 @@ STGFUN(StackUnderflowEnterNode)
FE_
}
+#else
+
+/*
+ We've inlined CommonUnderFlow because setting RetReg would zap
+ the return vector that the node needs.
+ We pick up the RetReg from the STkO header instead.
+ KH/HWL 14/2/97
+*/
+
+STGFUN(StackUnderflowEnterNode)
+{
+ P_ temp;
+ FB_
+ RetReg = STKO_RETURN(StkOReg); /* pick up return code from the StkO hdr
+ needed because we come from UpdatePAP */
+ LivenessReg = LIVENESS_R1;
+
+ temp = STKO_LINK(StkOReg);
+
+ /*? fprintf(stderr,"Stk Underflow from: %lx to: %lx size abandoned: %d\n",StkOReg,temp,STKO_CLOSURE_CTS_SIZE(StkOReg)); ?*/
+
+ /* change the guy we are abandoning into something
+ that will not be "interesting" on the mutables
+ list. (As long as it is there, it will be
+ scavenged in GC, and we cannot guarantee that
+ it is still a "sane" StkO object). (And, besides,
+ why continue to keep it [and all it pts to] alive?)
+ Will & Phil 95/10
+ */
+ FREEZE_MUT_HDR(StkOReg, ImMutArrayOfPtrs_info);
+ MUTUPLE_CLOSURE_SIZE(StkOReg) = MUTUPLE_VHS;
+
+ StkOReg = temp;
+ /* ToDo: Fetch the remote stack object here! */
+ RestoreStackStgRegs();
+ JMP_(EnterNodeCode); /* this will enter a PAP containing the old stkos
+ A and B stacks */
+ FE_
+}
#endif
+
+#endif /* !PAR */
+
const W_
vtbl_Underflow[] = {
/* "MAX_VECTORED_RTN" elements (see GhcConstants.lh) */
--
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