[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.

diff --git a/ghc/rts/GC.c b/ghc/rts/GC.c
index d978fce..713c579 100644 (file)
--- 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);