From 087c962f75d432cdd533991f403364e4782f83d5 Mon Sep 17 00:00:00 2001
From: Slava Pestov <slava@slava-pestovs-macbook-pro.local>
Date: Sun, 26 Apr 2009 16:05:09 -0500
Subject: [PATCH] VM: simplify GC a bit, add GC_DEBUG compile-time flag

---
 vm/code_block.c |  3 ++-
 vm/data_gc.c    |  4 ++--
 vm/data_gc.h    | 20 ++++++++++++++++++--
 vm/data_heap.h  |  1 -
 4 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/vm/code_block.c b/vm/code_block.c
index 8dda8bc16e..1ce440c9ab 100644
--- a/vm/code_block.c
+++ b/vm/code_block.c
@@ -224,7 +224,8 @@ void mark_object_code_block(CELL scan)
 	{
 	case WORD_TYPE:
 		word = (F_WORD *)scan;
-		mark_code_block(word->code);
+		if(word->code)
+		  mark_code_block(word->code);
 		if(word->profiling)
 			mark_code_block(word->profiling);
 		break;
diff --git a/vm/data_gc.c b/vm/data_gc.c
index 3ab2055d82..a1a86e7789 100755
--- a/vm/data_gc.c
+++ b/vm/data_gc.c
@@ -330,7 +330,7 @@ CELL copy_next_from_tenured(CELL scan)
 
 void copy_reachable_objects(CELL scan, CELL *end)
 {
-	if(HAVE_NURSERY_P && collecting_gen == NURSERY)
+	if(collecting_gen == NURSERY)
 	{
 		while(scan < *end)
 			scan = copy_next_from_nursery(scan);
@@ -405,7 +405,7 @@ void end_gc(CELL gc_elapsed)
 		if(collecting_gen != NURSERY)
 			reset_generations(NURSERY,collecting_gen - 1);
 	}
-	else if(HAVE_NURSERY_P && collecting_gen == NURSERY)
+	else if(collecting_gen == NURSERY)
 	{
 		nursery.here = nursery.start;
 	}
diff --git a/vm/data_gc.h b/vm/data_gc.h
index 52d8b603ad..afa45c5522 100755
--- a/vm/data_gc.h
+++ b/vm/data_gc.h
@@ -58,7 +58,7 @@ INLINE bool should_copy(CELL untagged)
 		return true;
 	else if(HAVE_AGING_P && collecting_gen == AGING)
 		return !in_zone(&data_heap->generations[TENURED],untagged);
-	else if(HAVE_NURSERY_P && collecting_gen == NURSERY)
+	else if(collecting_gen == NURSERY)
 		return in_zone(&nursery,untagged);
 	else
 	{
@@ -78,15 +78,31 @@ allocation (which does not call GC because of possible roots in volatile
 registers) does not run out of memory */
 #define ALLOT_BUFFER_ZONE 1024
 
+/* If this is defined, we GC every 100 allocations. This catches missing local roots */
+#ifdef GC_DEBUG
+static int count;
+#endif
+
 /*
  * It is up to the caller to fill in the object's fields in a meaningful
  * fashion!
  */
 INLINE void *allot_object(CELL type, CELL a)
 {
+
+#ifdef GC_DEBUG
+
+	if(!gc_off)
+	{
+		if(count++ % 1000 == 0)
+			gc();
+
+	}
+#endif
+
 	CELL *object;
 
-	if(HAVE_NURSERY_P && nursery.size - ALLOT_BUFFER_ZONE > a)
+	if(nursery.size - ALLOT_BUFFER_ZONE > a)
 	{
 		/* If there is insufficient room, collect the nursery */
 		if(nursery.here + ALLOT_BUFFER_ZONE + a > nursery.end)
diff --git a/vm/data_heap.h b/vm/data_heap.h
index a7f44e73f8..5836967295 100644
--- a/vm/data_heap.h
+++ b/vm/data_heap.h
@@ -37,7 +37,6 @@ F_DATA_HEAP *data_heap;
 
 /* the 0th generation is where new objects are allocated. */
 #define NURSERY 0
-#define HAVE_NURSERY_P (data_heap->gen_count>1)
 /* where objects hang around */
 #define AGING (data_heap->gen_count-2)
 #define HAVE_AGING_P (data_heap->gen_count>2)