Merge bleeding_edge 18021:18297

src/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 388 matching lines @@
   return compacting_;
 }
 
 
 void MarkCompactCollector::CollectGarbage() {
   // Make sure that Prepare() has been called. The individual steps below will
   // update the state as they proceed.
   ASSERT(state_ == PREPARE_GC);
   ASSERT(encountered_weak_collections_ == Smi::FromInt(0));
 
-  heap()->allocation_mementos_found_ = 0;
-
   MarkLiveObjects();
   ASSERT(heap_->incremental_marking()->IsStopped());
 
   if (FLAG_collect_maps) ClearNonLiveReferences();
 
   ClearWeakCollections();
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
     VerifyMarking(heap_);
@@ skipping 21 matching lines @@
 
   Finish();
 
   if (marking_parity_ == EVEN_MARKING_PARITY) {
     marking_parity_ = ODD_MARKING_PARITY;
   } else {
     ASSERT(marking_parity_ == ODD_MARKING_PARITY);
     marking_parity_ = EVEN_MARKING_PARITY;
   }
 
-  if (FLAG_trace_track_allocation_sites &&
-      heap()->allocation_mementos_found_ > 0) {
-    PrintF("AllocationMementos found during mark-sweep = %d\n",
-           heap()->allocation_mementos_found_);
-  }
   tracer_ = NULL;
 }
 
 
 #ifdef VERIFY_HEAP
 void MarkCompactCollector::VerifyMarkbitsAreClean(PagedSpace* space) {
   PageIterator it(space);
 
   while (it.has_next()) {
     Page* p = it.next();
@@ skipping 1372 matching lines @@
     // Mark all the objects reachable from the map and body.  May leave
     // overflowed objects in the heap.
     collector_->EmptyMarkingDeque();
   }
 
   MarkCompactCollector* collector_;
 };
 
 
 // Helper class for pruning the string table.
+template<bool finalize_external_strings>
 class StringTableCleaner : public ObjectVisitor {
  public:
   explicit StringTableCleaner(Heap* heap)
     : heap_(heap), pointers_removed_(0) { }
 
   virtual void VisitPointers(Object** start, Object** end) {
     // Visit all HeapObject pointers in [start, end).
     for (Object** p = start; p < end; p++) {
       Object* o = *p;
       if (o->IsHeapObject() &&
           !Marking::MarkBitFrom(HeapObject::cast(o)).Get()) {
-        // Check if the internalized string being pruned is external. We need to
-        // delete the associated external data as this string is going away.
-
-        // Since no objects have yet been moved we can safely access the map of
-        // the object.
-        if (o->IsExternalString()) {
+        if (finalize_external_strings) {
+          ASSERT(o->IsExternalString());
           heap_->FinalizeExternalString(String::cast(*p));
+        } else {
+          pointers_removed_++;
         }
         // Set the entry to the_hole_value (as deleted).
         *p = heap_->the_hole_value();
-        pointers_removed_++;
       }
     }
   }
 
   int PointersRemoved() {
+    ASSERT(!finalize_external_strings);
     return pointers_removed_;
   }
 
  private:
   Heap* heap_;
   int pointers_removed_;
 };
 
 
+typedef StringTableCleaner<false> InternalizedStringTableCleaner;
+typedef StringTableCleaner<true> ExternalStringTableCleaner;
+
+
 // Implementation of WeakObjectRetainer for mark compact GCs. All marked objects
 // are retained.
 class MarkCompactWeakObjectRetainer : public WeakObjectRetainer {
  public:
   virtual Object* RetainAs(Object* object) {
     if (Marking::MarkBitFrom(HeapObject::cast(object)).Get()) {
       return object;
+    } else if (object->IsAllocationSite() &&
+               !(AllocationSite::cast(object)->IsZombie())) {
+      // "dead" AllocationSites need to live long enough for a traversal of new
+      // space. These sites get a one-time reprieve.
+      AllocationSite* site = AllocationSite::cast(object);
+      site->MarkZombie();
+      site->GetHeap()->mark_compact_collector()->MarkAllocationSite(site);
+      return object;
     } else {
       return NULL;
     }
   }
 };
 
 
 // Fill the marking stack with overflowed objects returned by the given
 // iterator.  Stop when the marking stack is filled or the end of the space
 // is reached, whichever comes first.
@@ skipping 91 matching lines @@
     while (current_cell != 0) {
       int trailing_zeros = CompilerIntrinsics::CountTrailingZeros(current_cell);
       current_cell >>= trailing_zeros;
       offset += trailing_zeros;
       Address address = cell_base + offset * kPointerSize;
       HeapObject* object = HeapObject::FromAddress(address);
 
       int size = object->Size();
       survivors_size += size;
 
-      if (FLAG_trace_track_allocation_sites && object->IsJSObject()) {
-        if (AllocationMemento::FindForJSObject(JSObject::cast(object), true)
-            != NULL) {
-          heap()->allocation_mementos_found_++;
-        }
-      }
+      Heap::UpdateAllocationSiteFeedback(object);
 
       offset++;
       current_cell >>= 1;
       // Aggressively promote young survivors to the old space.
       if (TryPromoteObject(object, size)) {
         continue;
       }
 
       // Promotion failed. Just migrate object to another semispace.
       MaybeObject* allocation = new_space->AllocateRaw(size);
@@ skipping 72 matching lines @@
   StringTable* string_table = heap()->string_table();
   // Mark the string table itself.
   MarkBit string_table_mark = Marking::MarkBitFrom(string_table);
   SetMark(string_table, string_table_mark);
   // Explicitly mark the prefix.
   string_table->IteratePrefix(visitor);
   ProcessMarkingDeque();
 }
 
 
+void MarkCompactCollector::MarkAllocationSite(AllocationSite* site) {
+  MarkBit mark_bit = Marking::MarkBitFrom(site);
+  SetMark(site, mark_bit);
+}
+
+
 void MarkCompactCollector::MarkRoots(RootMarkingVisitor* visitor) {
   // Mark the heap roots including global variables, stack variables,
   // etc., and all objects reachable from them.
   heap()->IterateStrongRoots(visitor, VISIT_ONLY_STRONG);
 
   // Handle the string table specially.
   MarkStringTable(visitor);
 
   MarkWeakObjectToCodeTable();
 
@@ skipping 278 matching lines @@
   // Object literal map caches reference strings (cache keys) and maps
   // (cache values). At this point still useful maps have already been
   // marked. Mark the keys for the alive values before we process the
   // string table.
   ProcessMapCaches();
 
   // Prune the string table removing all strings only pointed to by the
   // string table.  Cannot use string_table() here because the string
   // table is marked.
   StringTable* string_table = heap()->string_table();
-  StringTableCleaner v(heap());
-  string_table->IterateElements(&v);
-  string_table->ElementsRemoved(v.PointersRemoved());
-  heap()->external_string_table_.Iterate(&v);
+  InternalizedStringTableCleaner internalized_visitor(heap());
+  string_table->IterateElements(&internalized_visitor);
+  string_table->ElementsRemoved(internalized_visitor.PointersRemoved());
+
+  ExternalStringTableCleaner external_visitor(heap());
+  heap()->external_string_table_.Iterate(&external_visitor);
   heap()->external_string_table_.CleanUp();
 
   // Process the weak references.
   MarkCompactWeakObjectRetainer mark_compact_object_retainer;
   heap()->ProcessWeakReferences(&mark_compact_object_retainer);
 
   // Remove object groups after marking phase.
   heap()->isolate()->global_handles()->RemoveObjectGroups();
   heap()->isolate()->global_handles()->RemoveImplicitRefGroups();
 
   // Flush code from collected candidates.
   if (is_code_flushing_enabled()) {
     code_flusher_->ProcessCandidates();
     // If incremental marker does not support code flushing, we need to
     // disable it before incremental marking steps for next cycle.
     if (FLAG_flush_code && !FLAG_flush_code_incrementally) {
       EnableCodeFlushing(false);
     }
   }
 
-  if (!FLAG_watch_ic_patching) {
-    // Clean up dead objects from the runtime profiler.
-    heap()->isolate()->runtime_profiler()->RemoveDeadSamples();
-  }
-
   if (FLAG_track_gc_object_stats) {
     heap()->CheckpointObjectStats();
   }
 }
 
 
 void MarkCompactCollector::ProcessMapCaches() {
   Object* raw_context = heap()->native_contexts_list_;
   while (raw_context != heap()->undefined_value()) {
     Context* context = reinterpret_cast<Context*>(raw_context);
@@ skipping 321 matching lines @@
 // to encounter pointers to dead new space objects during traversal of pointers
 // to new space.  We should clear them to avoid encountering them during next
 // pointer iteration.  This is an issue if the store buffer overflows and we
 // have to scan the entire old space, including dead objects, looking for
 // pointers to new space.
 void MarkCompactCollector::MigrateObject(Address dst,
                                          Address src,
                                          int size,
                                          AllocationSpace dest) {
   HeapProfiler* heap_profiler = heap()->isolate()->heap_profiler();
-  if (heap_profiler->is_profiling()) {
+  if (heap_profiler->is_tracking_object_moves()) {
     heap_profiler->ObjectMoveEvent(src, dst, size);
   }
   ASSERT(heap()->AllowedToBeMigrated(HeapObject::FromAddress(src), dest));
   ASSERT(dest != LO_SPACE && size <= Page::kMaxNonCodeHeapObjectSize);
   if (dest == OLD_POINTER_SPACE) {
     Address src_slot = src;
     Address dst_slot = dst;
     ASSERT(IsAligned(size, kPointerSize));
 
     for (int remaining = size / kPointerSize; remaining > 0; remaining--) {
@@ skipping 725 matching lines @@
     WeakHashTable* table =
         WeakHashTable::cast(heap_->weak_object_to_code_table());
     table->Iterate(&updating_visitor);
     table->Rehash(heap_->undefined_value());
   }
 
   // Update pointers from external string table.
   heap_->UpdateReferencesInExternalStringTable(
       &UpdateReferenceInExternalStringTableEntry);
 
-  if (!FLAG_watch_ic_patching) {
-    // Update JSFunction pointers from the runtime profiler.
-    heap()->isolate()->runtime_profiler()->UpdateSamplesAfterCompact(
-        &updating_visitor);
-  }
-
   EvacuationWeakObjectRetainer evacuation_object_retainer;
   heap()->ProcessWeakReferences(&evacuation_object_retainer);
 
   // Visit invalidated code (we ignored all slots on it) and clear mark-bits
   // under it.
   ProcessInvalidatedCode(&updating_visitor);
 
   heap_->isolate()->inner_pointer_to_code_cache()->Flush();
 
 #ifdef VERIFY_HEAP
@@ skipping 834 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal