Merge bleeding_edge 18021:18297

src/heap.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 69 matching lines @@
 // Will be 4 * reserved_semispace_size_ to ensure that young
 // generation can be aligned to its size.
       maximum_committed_(0),
       survived_since_last_expansion_(0),
       sweep_generation_(0),
       always_allocate_scope_depth_(0),
       linear_allocation_scope_depth_(0),
       contexts_disposed_(0),
       global_ic_age_(0),
       flush_monomorphic_ics_(false),
-      allocation_mementos_found_(0),
       scan_on_scavenge_pages_(0),
       new_space_(this),
       old_pointer_space_(NULL),
       old_data_space_(NULL),
       code_space_(NULL),
       map_space_(NULL),
       cell_space_(NULL),
       property_cell_space_(NULL),
       lo_space_(NULL),
       gc_state_(NOT_IN_GC),
@@ skipping 398 matching lines @@
   PagedSpaces spaces(this);
   for (PagedSpace* space = spaces.next();
        space != NULL;
        space = spaces.next()) {
     space->RepairFreeListsAfterBoot();
   }
 }
 
 
 void Heap::GarbageCollectionEpilogue() {
+  if (FLAG_allocation_site_pretenuring) {
+    int tenure_decisions = 0;
+    int dont_tenure_decisions = 0;
+    int allocation_mementos_found = 0;
+
+    Object* cur = allocation_sites_list();
+    while (cur->IsAllocationSite()) {
+      AllocationSite* casted = AllocationSite::cast(cur);
+      allocation_mementos_found += casted->memento_found_count()->value();
+      if (casted->DigestPretenuringFeedback()) {
+        if (casted->GetPretenureMode() == TENURED) {
+          tenure_decisions++;
+        } else {
+          dont_tenure_decisions++;
+        }
+      }
+      cur = casted->weak_next();
+    }
+
+    // TODO(mvstanton): Pretenure decisions are only made once for an allocation
+    // site. Find a sane way to decide about revisiting the decision later.
+
+    if (FLAG_trace_track_allocation_sites &&
+        (allocation_mementos_found > 0 ||
+         tenure_decisions > 0 ||
+         dont_tenure_decisions > 0)) {
+      PrintF("GC: (#mementos, #tenure decisions, #donttenure decisions) "
+             "(%d, %d, %d)\n",
+             allocation_mementos_found,
+             tenure_decisions,
+             dont_tenure_decisions);
+    }
+  }
+
   store_buffer()->GCEpilogue();
 
   // In release mode, we only zap the from space under heap verification.
   if (Heap::ShouldZapGarbage()) {
     ZapFromSpace();
   }
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
     Verify();
@@ skipping 867 matching lines @@
   }
 
  private:
   Heap* heap_;
 };
 
 
 void Heap::Scavenge() {
   RelocationLock relocation_lock(this);
 
-  allocation_mementos_found_ = 0;
-
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) VerifyNonPointerSpacePointers(this);
 #endif
 
   gc_state_ = SCAVENGE;
 
   // Implements Cheney's copying algorithm
   LOG(isolate_, ResourceEvent("scavenge", "begin"));
 
   // Clear descriptor cache.
@@ skipping 102 matching lines @@
       &IsUnscavengedHeapObject);
   isolate_->global_handles()->IterateNewSpaceWeakIndependentRoots(
       &scavenge_visitor);
   new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
 
   UpdateNewSpaceReferencesInExternalStringTable(
       &UpdateNewSpaceReferenceInExternalStringTableEntry);
 
   promotion_queue_.Destroy();
 
-  if (!FLAG_watch_ic_patching) {
-    isolate()->runtime_profiler()->UpdateSamplesAfterScavenge();
-  }
   incremental_marking()->UpdateMarkingDequeAfterScavenge();
 
   ScavengeWeakObjectRetainer weak_object_retainer(this);
   ProcessWeakReferences(&weak_object_retainer);
 
   ASSERT(new_space_front == new_space_.top());
 
   // Set age mark.
   new_space_.set_age_mark(new_space_.top());
 
   new_space_.LowerInlineAllocationLimit(
       new_space_.inline_allocation_limit_step());
 
   // Update how much has survived scavenge.
   IncrementYoungSurvivorsCounter(static_cast<int>(
       (PromotedSpaceSizeOfObjects() - survived_watermark) + new_space_.Size()));
 
   LOG(isolate_, ResourceEvent("scavenge", "end"));
 
   gc_state_ = NOT_IN_GC;
 
   scavenges_since_last_idle_round_++;
-
-  if (FLAG_trace_track_allocation_sites && allocation_mementos_found_ > 0) {
-    PrintF("AllocationMementos found during scavenge = %d\n",
-           allocation_mementos_found_);
-  }
 }
 
 
 String* Heap::UpdateNewSpaceReferenceInExternalStringTableEntry(Heap* heap,
                                                                 Object** p) {
   MapWord first_word = HeapObject::cast(*p)->map_word();
 
   if (!first_word.IsForwardingAddress()) {
     // Unreachable external string can be finalized.
     heap->FinalizeExternalString(String::cast(*p));
@@ skipping 348 matching lines @@
   Object* allocation_site_obj =
       VisitWeakList<AllocationSite>(this,
                                     allocation_sites_list(),
                                     retainer, record_slots);
   set_allocation_sites_list(allocation_site_obj);
 }
 
 
 void Heap::VisitExternalResources(v8::ExternalResourceVisitor* visitor) {
   DisallowHeapAllocation no_allocation;
-
-  // Both the external string table and the string table may contain
-  // external strings, but neither lists them exhaustively, nor is the
-  // intersection set empty.  Therefore we iterate over the external string
-  // table first, ignoring internalized strings, and then over the
-  // internalized string table.
+  // All external strings are listed in the external string table.
 
   class ExternalStringTableVisitorAdapter : public ObjectVisitor {
    public:
     explicit ExternalStringTableVisitorAdapter(
         v8::ExternalResourceVisitor* visitor) : visitor_(visitor) {}
     virtual void VisitPointers(Object** start, Object** end) {
       for (Object** p = start; p < end; p++) {
-        // Visit non-internalized external strings,
-        // since internalized strings are listed in the string table.
-        if (!(*p)->IsInternalizedString()) {
-          ASSERT((*p)->IsExternalString());
-          visitor_->VisitExternalString(Utils::ToLocal(
-              Handle<String>(String::cast(*p))));
-        }
+        ASSERT((*p)->IsExternalString());
+        visitor_->VisitExternalString(Utils::ToLocal(
+            Handle<String>(String::cast(*p))));
       }
     }
    private:
     v8::ExternalResourceVisitor* visitor_;
   } external_string_table_visitor(visitor);
 
   external_string_table_.Iterate(&external_string_table_visitor);
-
-  class StringTableVisitorAdapter : public ObjectVisitor {
-   public:
-    explicit StringTableVisitorAdapter(
-        v8::ExternalResourceVisitor* visitor) : visitor_(visitor) {}
-    virtual void VisitPointers(Object** start, Object** end) {
-      for (Object** p = start; p < end; p++) {
-        if ((*p)->IsExternalString()) {
-          ASSERT((*p)->IsInternalizedString());
-          visitor_->VisitExternalString(Utils::ToLocal(
-              Handle<String>(String::cast(*p))));
-        }
-      }
-    }
-   private:
-    v8::ExternalResourceVisitor* visitor_;
-  } string_table_visitor(visitor);
-
-  string_table()->IterateElements(&string_table_visitor);
 }
 
 
 class NewSpaceScavenger : public StaticNewSpaceVisitor<NewSpaceScavenger> {
  public:
   static inline void VisitPointer(Heap* heap, Object** p) {
     Object* object = *p;
     if (!heap->InNewSpace(object)) return;
     Heap::ScavengeObject(reinterpret_cast<HeapObject**>(p),
                          reinterpret_cast<HeapObject*>(object));
@@ skipping 189 matching lines @@
     heap->CopyBlock(target->address(), source->address(), size);
 
     // Set the forwarding address.
     source->set_map_word(MapWord::FromForwardingAddress(target));
 
     if (logging_and_profiling_mode == LOGGING_AND_PROFILING_ENABLED) {
       // Update NewSpace stats if necessary.
       RecordCopiedObject(heap, target);
       Isolate* isolate = heap->isolate();
       HeapProfiler* heap_profiler = isolate->heap_profiler();
-      if (heap_profiler->is_profiling()) {
+      if (heap_profiler->is_tracking_object_moves()) {
         heap_profiler->ObjectMoveEvent(source->address(), target->address(),
                                        size);
       }
       if (isolate->logger()->is_logging_code_events() ||
           isolate->cpu_profiler()->is_profiling()) {
         if (target->IsSharedFunctionInfo()) {
           PROFILE(isolate, SharedFunctionInfoMoveEvent(
               source->address(), target->address()));
         }
       }
@@ skipping 230 matching lines @@
                     LOGGING_AND_PROFILING_ENABLED>::Initialize();
   ScavengingVisitor<IGNORE_MARKS, LOGGING_AND_PROFILING_ENABLED>::Initialize();
 }
 
 
 void Heap::SelectScavengingVisitorsTable() {
   bool logging_and_profiling =
       isolate()->logger()->is_logging() ||
       isolate()->cpu_profiler()->is_profiling() ||
       (isolate()->heap_profiler() != NULL &&
-       isolate()->heap_profiler()->is_profiling());
+       isolate()->heap_profiler()->is_tracking_object_moves());
 
   if (!incremental_marking()->IsMarking()) {
     if (!logging_and_profiling) {
       scavenging_visitors_table_.CopyFrom(
           ScavengingVisitor<IGNORE_MARKS,
                             LOGGING_AND_PROFILING_DISABLED>::GetTable());
     } else {
       scavenging_visitors_table_.CopyFrom(
           ScavengingVisitor<IGNORE_MARKS,
                             LOGGING_AND_PROFILING_ENABLED>::GetTable());
@@ skipping 1526 matching lines @@
 }
 
 
 MaybeObject* Heap::AllocateSubString(String* buffer,
                                      int start,
                                      int end,
                                      PretenureFlag pretenure) {
   int length = end - start;
   if (length <= 0) {
     return empty_string();
-  } else if (length == 1) {
+  }
+
+  // Make an attempt to flatten the buffer to reduce access time.
+  buffer = buffer->TryFlattenGetString();
+
+  if (length == 1) {
     return LookupSingleCharacterStringFromCode(buffer->Get(start));
   } else if (length == 2) {
     // Optimization for 2-byte strings often used as keys in a decompression
     // dictionary.  Check whether we already have the string in the string
     // table to prevent creation of many unnecessary strings.
     uint16_t c1 = buffer->Get(start);
     uint16_t c2 = buffer->Get(start + 1);
     return MakeOrFindTwoCharacterString(this, c1, c2);
   }
 
-  // Make an attempt to flatten the buffer to reduce access time.
-  buffer = buffer->TryFlattenGetString();
-
   if (!FLAG_string_slices ||
       !buffer->IsFlat() ||
       length < SlicedString::kMinLength ||
       pretenure == TENURED) {
     Object* result;
     // WriteToFlat takes care of the case when an indirect string has a
     // different encoding from its underlying string.  These encodings may
     // differ because of externalization.
     bool is_one_byte = buffer->IsOneByteRepresentation();
     { MaybeObject* maybe_result = is_one_byte
@@ skipping 355 matching lines @@
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
     code->Verify();
   }
 #endif
   return new_code;
 }
 
 
+void Heap::InitializeAllocationMemento(AllocationMemento* memento,
+                                       AllocationSite* allocation_site) {
+  memento->set_map_no_write_barrier(allocation_memento_map());
+  ASSERT(allocation_site->map() == allocation_site_map());
+  memento->set_allocation_site(allocation_site, SKIP_WRITE_BARRIER);
+  if (FLAG_allocation_site_pretenuring) {
+    allocation_site->IncrementMementoCreateCount();
+  }
+}
+
+
 MaybeObject* Heap::AllocateWithAllocationSite(Map* map, AllocationSpace space,
     Handle<AllocationSite> allocation_site) {
   ASSERT(gc_state_ == NOT_IN_GC);
   ASSERT(map->instance_type() != MAP_TYPE);
   // If allocation failures are disallowed, we may allocate in a different
   // space when new space is full and the object is not a large object.
   AllocationSpace retry_space =
       (space != NEW_SPACE) ? space : TargetSpaceId(map->instance_type());
   int size = map->instance_size() + AllocationMemento::kSize;
   Object* result;
   MaybeObject* maybe_result = AllocateRaw(size, space, retry_space);
   if (!maybe_result->ToObject(&result)) return maybe_result;
   // No need for write barrier since object is white and map is in old space.
   HeapObject::cast(result)->set_map_no_write_barrier(map);
   AllocationMemento* alloc_memento = reinterpret_cast<AllocationMemento*>(
       reinterpret_cast<Address>(result) + map->instance_size());
-  alloc_memento->set_map_no_write_barrier(allocation_memento_map());
-  ASSERT(allocation_site->map() == allocation_site_map());
-  alloc_memento->set_allocation_site(*allocation_site, SKIP_WRITE_BARRIER);
+  InitializeAllocationMemento(alloc_memento, *allocation_site);
   return result;
 }
 
 
 MaybeObject* Heap::Allocate(Map* map, AllocationSpace space) {
   ASSERT(gc_state_ == NOT_IN_GC);
   ASSERT(map->instance_type() != MAP_TYPE);
   // If allocation failures are disallowed, we may allocate in a different
   // space when new space is full and the object is not a large object.
   AllocationSpace retry_space =
@@ skipping 412 matching lines @@
 MaybeObject* Heap::CopyJSObject(JSObject* source, AllocationSite* site) {
   // Never used to copy functions.  If functions need to be copied we
   // have to be careful to clear the literals array.
   SLOW_ASSERT(!source->IsJSFunction());
 
   // Make the clone.
   Map* map = source->map();
   int object_size = map->instance_size();
   Object* clone;
 
-  ASSERT(site == NULL || (AllocationSite::CanTrack(map->instance_type()) &&
-                          map->instance_type() == JS_ARRAY_TYPE));
+  ASSERT(site == NULL || AllocationSite::CanTrack(map->instance_type()));
 
   WriteBarrierMode wb_mode = UPDATE_WRITE_BARRIER;
 
   // If we're forced to always allocate, we use the general allocation
   // functions which may leave us with an object in old space.
   if (always_allocate()) {
     { MaybeObject* maybe_clone =
           AllocateRaw(object_size, NEW_SPACE, OLD_POINTER_SPACE);
       if (!maybe_clone->ToObject(&clone)) return maybe_clone;
     }
@@ skipping 18 matching lines @@
     SLOW_ASSERT(InNewSpace(clone));
     // Since we know the clone is allocated in new space, we can copy
     // the contents without worrying about updating the write barrier.
     CopyBlock(HeapObject::cast(clone)->address(),
               source->address(),
               object_size);
 
     if (site != NULL) {
       AllocationMemento* alloc_memento = reinterpret_cast<AllocationMemento*>(
           reinterpret_cast<Address>(clone) + object_size);
-      alloc_memento->set_map_no_write_barrier(allocation_memento_map());
-      ASSERT(site->map() == allocation_site_map());
-      alloc_memento->set_allocation_site(site, SKIP_WRITE_BARRIER);
-      HeapProfiler* profiler = isolate()->heap_profiler();
-      if (profiler->is_tracking_allocations()) {
-        profiler->UpdateObjectSizeEvent(HeapObject::cast(clone)->address(),
-                                        object_size);
-        profiler->NewObjectEvent(alloc_memento->address(),
-                                 AllocationMemento::kSize);
-      }
+      InitializeAllocationMemento(alloc_memento, site);
     }
   }
 
   SLOW_ASSERT(
       JSObject::cast(clone)->GetElementsKind() == source->GetElementsKind());
   FixedArrayBase* elements = FixedArrayBase::cast(source->elements());
   FixedArray* properties = FixedArray::cast(source->properties());
   // Update elements if necessary.
   if (elements->length() > 0) {
     Object* elem;
@@ skipping 103 matching lines @@
   // Reset the map for the object.
   object->set_map(constructor->initial_map());
 
   // Reinitialize the object from the constructor map.
   InitializeJSObjectFromMap(object, FixedArray::cast(properties), map);
   return object;
 }
 
 
 MaybeObject* Heap::AllocateStringFromOneByte(Vector<const uint8_t> string,
-                                           PretenureFlag pretenure) {
+                                             PretenureFlag pretenure) {
   int length = string.length();
   if (length == 1) {
     return Heap::LookupSingleCharacterStringFromCode(string[0]);
   }
   Object* result;
   { MaybeObject* maybe_result =
         AllocateRawOneByteString(string.length(), pretenure);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
 
@@ skipping 2966 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   OS::MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   OS::MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal