Objects can no longer be migrated or evacuated into large object space.

BUG=
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/19959007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15848 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 815cae5..e73127f 100644 (file)
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -2722,7 +2722,9 @@ void MarkCompactCollector::MigrateObject(Address dst,
                                          int size,
                                          AllocationSpace dest) {
   HEAP_PROFILE(heap(), ObjectMoveEvent(src, dst));
-  if (dest == OLD_POINTER_SPACE || dest == LO_SPACE) {
+  // TODO(hpayer): Replace that check with an assert.
+  CHECK(dest != LO_SPACE && size <= Page::kMaxNonCodeHeapObjectSize);
+  if (dest == OLD_POINTER_SPACE) {
     Address src_slot = src;
     Address dst_slot = dst;
     ASSERT(IsAligned(size, kPointerSize));
@@ -2894,37 +2896,24 @@ static String* UpdateReferenceInExternalStringTableEntry(Heap* heap,
 
 bool MarkCompactCollector::TryPromoteObject(HeapObject* object,
                                             int object_size) {
-  Object* result;
+  // TODO(hpayer): Replace that check with an assert.
+  CHECK(object_size <= Page::kMaxNonCodeHeapObjectSize);
 
-  if (object_size > Page::kMaxNonCodeHeapObjectSize) {
-    MaybeObject* maybe_result =
-        heap()->lo_space()->AllocateRaw(object_size, NOT_EXECUTABLE);
-    if (maybe_result->ToObject(&result)) {
-      HeapObject* target = HeapObject::cast(result);
-      MigrateObject(target->address(),
-                    object->address(),
-                    object_size,
-                    LO_SPACE);
-      heap()->mark_compact_collector()->tracer()->
-          increment_promoted_objects_size(object_size);
-      return true;
-    }
-  } else {
-    OldSpace* target_space = heap()->TargetSpace(object);
-
-    ASSERT(target_space == heap()->old_pointer_space() ||
-           target_space == heap()->old_data_space());
-    MaybeObject* maybe_result = target_space->AllocateRaw(object_size);
-    if (maybe_result->ToObject(&result)) {
-      HeapObject* target = HeapObject::cast(result);
-      MigrateObject(target->address(),
-                    object->address(),
-                    object_size,
-                    target_space->identity());
-      heap()->mark_compact_collector()->tracer()->
-          increment_promoted_objects_size(object_size);
-      return true;
-    }
+  OldSpace* target_space = heap()->TargetSpace(object);
+
+  ASSERT(target_space == heap()->old_pointer_space() ||
+         target_space == heap()->old_data_space());
+  Object* result;
+  MaybeObject* maybe_result = target_space->AllocateRaw(object_size);
+  if (maybe_result->ToObject(&result)) {
+    HeapObject* target = HeapObject::cast(result);
+    MigrateObject(target->address(),
+                  object->address(),
+                  object_size,
+                  target_space->identity());
+    heap()->mark_compact_collector()->tracer()->
+        increment_promoted_objects_size(object_size);
+    return true;
   }
 
   return false;

diff --git a/src/spaces.h b/src/spaces.h
index dda5591..b47452e 100644 (file)
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -781,7 +781,10 @@ class Page : public MemoryChunk {
   // Object area size in bytes.
   static const int kNonCodeObjectAreaSize = kPageSize - kObjectStartOffset;
 
-  // Maximum object size that fits in a page.
+  // Maximum object size that fits in a page. Objects larger than that size
+  // are allocated in large object space and are never moved in memory. This
+  // also applies to new space allocation, since objects are never migrated
+  // from new space to large object space.
   static const int kMaxNonCodeHeapObjectSize = kNonCodeObjectAreaSize;
 
   // Page size mask.