From 3a7e4d98248a28b2b7418e136759089f887bd195 Mon Sep 17 00:00:00 2001
From: simonmar <unknown>
Date: Mon, 1 Oct 2001 10:52:36 +0000
Subject: [PATCH] [project @ 2001-10-01 10:52:36 by simonmar] Fix a bug in the
 heap size calculation, where a negative result wasn't
 noticed because we're working with unsigned types.  We now
 explicitly test that the heap has enough room for the
 minimum allocation area size, otherwise a heap overflow is
 reported.

---
 ghc/rts/GC.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/ghc/rts/GC.c b/ghc/rts/GC.c
index d978fce..713c579 100644
--- a/ghc/rts/GC.c
+++ b/ghc/rts/GC.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: GC.c,v 1.122 2001/08/30 10:22:52 simonmar Exp $
+ * $Id: GC.c,v 1.123 2001/10/01 10:52:36 simonmar Exp $
  *
  * (c) The GHC Team 1998-1999
  *
@@ -758,6 +758,14 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc )
       // different if compaction is turned on, because we don't need
       // to double the space required to collect the old generation.
       if (max != 0) {
+
+	  // this test is necessary to ensure that the calculations
+	  // below don't have any negative results - we're working
+	  // with unsigned values here.
+	  if (max < min_alloc) {
+	      heapOverflow();
+	  }
+
 	  if (oldest_gen->steps[0].is_compacted) {
 	      if ( (size + (size - 1) * (gens - 2) * 2) + min_alloc > max ) {
 		  size = (max - min_alloc) / ((gens - 1) * 2 - 1);
-- 
1.7.10.4