Reorganisation of the source tree

Most of the other users of the fptools build system have migrated to
Cabal, and with the move to darcs we can now flatten the source tree
without losing history, so here goes.

The main change is that the ghc/ subdir is gone, and most of what it
contained is now at the top level.  The build system now makes no
pretense at being multi-project, it is just the GHC build system.

No doubt this will break many things, and there will be a period of
instability while we fix the dependencies.  A straightforward build
should work, but I haven't yet fixed binary/source distributions.
Changes to the Building Guide will follow, too.

1 files changed, 97 insertions, 0 deletions

diff --git a/rts/Weak.c b/rts/Weak.c
new file mode 100644
index 0000000000..f010395221
--- /dev/null
+++ b/rts/Weak.c
@@ -0,0 +1,97 @@
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The GHC Team, 1998-1999
+ *
+ * Weak pointers / finalizers
+ *
+ * ---------------------------------------------------------------------------*/
+
+#include "PosixSource.h"
+#define COMPILING_RTS_MAIN
+#include "Rts.h"
+#include "RtsUtils.h"
+#include "SchedAPI.h"
+#include "RtsFlags.h"
+#include "Weak.h"
+#include "Storage.h"
+#include "Schedule.h"
+#include "Prelude.h"
+#include "RtsAPI.h"
+
+StgWeak *weak_ptr_list;
+
+/*
+ * scheduleFinalizers() is called on the list of weak pointers found
+ * to be dead after a garbage collection.  It overwrites each object
+ * with DEAD_WEAK, and creates a new thread to run the pending finalizers.
+ *
+ * This function is called just after GC.  The weak pointers on the
+ * argument list are those whose keys were found to be not reachable,
+ * however the value and finalizer fields have by now been marked live.
+ * The weak pointer object itself may not be alive - i.e. we may be
+ * looking at either an object in from-space or one in to-space.  It
+ * doesn't really matter either way.
+ *
+ * Pre-condition: sched_mutex _not_ held.
+ */
+
+void
+scheduleFinalizers(Capability *cap, StgWeak *list)
+{
+    StgWeak *w;
+    StgTSO *t;
+    StgMutArrPtrs *arr;
+    nat n;
+
+    // count number of finalizers, and kill all the weak pointers first...
+    n = 0;
+    for (w = list; w; w = w->link) { 
+
+	// Better not be a DEAD_WEAK at this stage; the garbage
+	// collector removes DEAD_WEAKs from the weak pointer list.
+	ASSERT(w->header.info != &stg_DEAD_WEAK_info);
+
+	if (w->finalizer != &stg_NO_FINALIZER_closure) {
+	    n++;
+	}
+
+#ifdef PROFILING
+        // A weak pointer is inherently used, so we do not need to call
+        // LDV_recordDead().
+	//
+        // Furthermore, when PROFILING is turned on, dead weak
+        // pointers are exactly as large as weak pointers, so there is
+        // no need to fill the slop, either.  See stg_DEAD_WEAK_info
+        // in StgMiscClosures.hc.
+#endif
+	SET_HDR(w, &stg_DEAD_WEAK_info, w->header.prof.ccs);
+    }
+	
+    // No finalizers to run?
+    if (n == 0) return;
+
+    IF_DEBUG(weak,debugBelch("weak: batching %d finalizers\n", n));
+
+    arr = (StgMutArrPtrs *)allocateLocal(cap, sizeofW(StgMutArrPtrs) + n);
+    TICK_ALLOC_PRIM(sizeofW(StgMutArrPtrs), n, 0);
+    SET_HDR(arr, &stg_MUT_ARR_PTRS_FROZEN_info, CCS_SYSTEM);
+    arr->ptrs = n;
+
+    n = 0;
+    for (w = list; w; w = w->link) {
+	if (w->finalizer != &stg_NO_FINALIZER_closure) {
+	    arr->payload[n] = w->finalizer;
+	    n++;
+	}
+    }
+
+    t = createIOThread(cap, 
+		       RtsFlags.GcFlags.initialStkSize, 
+		       rts_apply(cap,
+			   rts_apply(cap,
+			       (StgClosure *)runFinalizerBatch_closure,
+			       rts_mkInt(cap,n)), 
+			   (StgClosure *)arr)
+	);
+    scheduleThread(cap,t);
+}