From: simonmar <unknown>
Date: Mon, 7 Nov 2005 14:43:34 +0000 (+0000)
Subject: [project @ 2005-11-07 14:43:34 by simonmar]
X-Git-Tag: Initial_conversion_from_CVS_complete~63
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=6470f502f738e3b7b1348089deb3a7fbec221f1e;p=ghc-hetmet.git

[project @ 2005-11-07 14:43:34 by simonmar]
Fix some problems with array thawing/freezing and the GC.
---

diff --git a/ghc/rts/ClosureFlags.c b/ghc/rts/ClosureFlags.c
index 8a3d97a..df9ef7b 100644
--- a/ghc/rts/ClosureFlags.c
+++ b/ghc/rts/ClosureFlags.c
@@ -78,7 +78,7 @@ StgWord16 closure_flags[] = {
 /* MVAR		   	= */ (_HNF|     _NS|         _MUT|_UPT           ),
 /* ARR_WORDS		= */ (_HNF|     _NS|              _UPT           ),
 /* MUT_ARR_PTRS	   	= */ (_HNF|     _NS|         _MUT|_UPT           ),
-/* MUT_ARR_PTRS_FROZEN0	= */ (_HNF|     _NS|              _UPT           ),
+/* MUT_ARR_PTRS_FROZEN0	= */ (_HNF|     _NS|         _MUT|_UPT           ),
 /* MUT_ARR_PTRS_FROZEN 	= */ (_HNF|     _NS|              _UPT           ),
 /* MUT_VAR		= */ (_HNF|     _NS|         _MUT|_UPT           ),
 /* WEAK		   	= */ (_HNF|     _NS|              _UPT           ),
diff --git a/ghc/rts/GC.c b/ghc/rts/GC.c
index 9a21af8..0399d60 100644
--- a/ghc/rts/GC.c
+++ b/ghc/rts/GC.c
@@ -2953,10 +2953,14 @@ scavenge(step *stp)
 	for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
 	    *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p);
 	}
-	// it's tempting to recordMutable() if failed_to_evac is
-	// false, but that breaks some assumptions (eg. every
-	// closure on the mutable list is supposed to have the MUT
-	// flag set, and MUT_ARR_PTRS_FROZEN doesn't).
+
+	// If we're going to put this object on the mutable list, then
+	// set its info ptr to MUT_ARR_PTRS_FROZEN0 to indicate that.
+	if (failed_to_evac) {
+	    ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN0_info;
+	} else {
+	    ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN_info;
+	}
 	break;
     }
 
@@ -3307,12 +3311,20 @@ linear_scan:
 	case MUT_ARR_PTRS_FROZEN0:
 	    // follow everything 
 	{
-	    StgPtr next;
+	    StgPtr next, q = p;
 	    
 	    next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
 	    for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
 		*p = (StgWord)(StgPtr)evacuate((StgClosure *)*p);
 	    }
+
+	    // If we're going to put this object on the mutable list, then
+	    // set its info ptr to MUT_ARR_PTRS_FROZEN0 to indicate that.
+	    if (failed_to_evac) {
+		((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN0_info;
+	    } else {
+		((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN_info;
+	    }
 	    break;
 	}
 
@@ -3621,12 +3633,20 @@ scavenge_one(StgPtr p)
     case MUT_ARR_PTRS_FROZEN0:
     {
 	// follow everything 
-	StgPtr next;
+	StgPtr next, q=p;
       
 	next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
 	for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
 	    *p = (StgWord)(StgPtr)evacuate((StgClosure *)*p);
 	}
+
+	// If we're going to put this object on the mutable list, then
+	// set its info ptr to MUT_ARR_PTRS_FROZEN0 to indicate that.
+	if (failed_to_evac) {
+	    ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN0_info;
+	} else {
+	    ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN_info;
+	}
 	break;
     }
 
diff --git a/ghc/rts/PrimOps.cmm b/ghc/rts/PrimOps.cmm
index 1eaf727..630319f 100644
--- a/ghc/rts/PrimOps.cmm
+++ b/ghc/rts/PrimOps.cmm
@@ -126,21 +126,25 @@ unsafeThawArrayzh_fast
   // the mutable list is not easy, because the mut_list is only singly-linked).
   // 
   // So that we can tell whether a MUT_ARR_PTRS_FROZEN is on the mutable list,
-  // when we freeze it we set the info ptr to be MUT_ARR_PTRS_FROZEN0 to indicate
-  // that it is still on the mutable list.
-
+  // when we freeze it we set the info ptr to be MUT_ARR_PTRS_FROZEN0
+  // to indicate that it is still on the mutable list.
+  //
   // So, when we thaw a MUT_ARR_PTRS_FROZEN, we must cope with two cases:
   // either it is on a mut_list, or it isn't.  We adopt the convention that
   // the closure type is MUT_ARR_PTRS_FROZEN0 if it is on the mutable list,
-  // and MUT_ARR_PTRS_FROZEN otherwise.
+  // and MUT_ARR_PTRS_FROZEN otherwise.  In fact it wouldn't matter if
+  // we put it on the mutable list more than once, but it would get scavenged
+  // multiple times during GC, which would be unnecessarily slow.
   //
-  if (%INFO_TYPE(%GET_STD_INFO(R1)) != HALF_W_(MUT_ARR_PTRS_FROZEN0)) {
+  if (StgHeader_info(R1) != stg_MUT_ARR_PTRS_FROZEN0_info) {
+	SET_INFO(R1,stg_MUT_ARR_PTRS_info);
 	foreign "C" recordMutableLock(R1 "ptr") [R1];
+	// must be done after SET_INFO, because it ASSERTs closure_MUTABLE()
+	RET_P(R1);
+  } else {
+	SET_INFO(R1,stg_MUT_ARR_PTRS_info);
+	RET_P(R1);
   }
-
-  SET_INFO(R1,stg_MUT_ARR_PTRS_info);
-
-  RET_P(R1);
 }
 
 /* -----------------------------------------------------------------------------