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deps: backport e093a04, 09db540 from upstream V8
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Original commit messages:
v8/v8@e093a04
  Rehash and clear deleted entries in weak collections during GC
  Otherwise, they'll just keep growing until we run out of memory or hit the FixedArray's maximum capacity.

  BUG=v8:4909
  R=hpayer@chromium.org
  LOG=n

  Review URL: https://codereview.chromium.org/1877233005

  Cr-Commit-Position: refs/heads/master@{#35514}

v8/v8@09db540
  Reland of Rehash and clear deleted entries in weak collections during GC
  BUG=v8:4909
  R=hpayer@chromium.org,ulan@chromium.org
  LOG=n

  Review URL: https://codereview.chromium.org/1890123002

  Cr-Commit-Position: refs/heads/master@{#35538}

Ref: https://crbug.com/v8/4909
Ref: #7883
Fixes: #6180
PR-URL: #7689
Reviewed-By: Matt Loring <mattloring@google.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
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ofrobots authored and Myles Borins committed Oct 10, 2016
1 parent d71dfdd commit 5ab6edd
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Showing 5 changed files with 41 additions and 3 deletions.
7 changes: 7 additions & 0 deletions deps/v8/src/heap/mark-compact.cc
Original file line number Diff line number Diff line change
Expand Up @@ -2614,6 +2614,13 @@ void MarkCompactCollector::ClearWeakCollections() {
table->RemoveEntry(i);
}
}
// Rehash if more than 25% of the entries are deleted entries.
// TODO(jochen): Consider to shrink the fixed array in place.
if ((table->NumberOfDeletedElements() << kJSWeakCollectionLoadFactorExp) >
table->NumberOfElements()) {
HandleScope scope(heap()->isolate());
table->Rehash(heap()->isolate()->factory()->undefined_value());
}
}
weak_collection_obj = weak_collection->next();
weak_collection->set_next(heap()->undefined_value());
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4 changes: 4 additions & 0 deletions deps/v8/src/heap/mark-compact.h
Original file line number Diff line number Diff line change
Expand Up @@ -612,6 +612,10 @@ class MarkCompactCollector {
static const uint32_t kSingleFreeEncoding = 0;
static const uint32_t kMultiFreeEncoding = 1;

// If the number of deleted slots in a JSWeakCollection exceeds the number
// of entries / 2^(factor), we rehash the table.
static const int kJSWeakCollectionLoadFactorExp = 1;

static inline bool IsMarked(Object* obj);
static bool IsUnmarkedHeapObjectWithHeap(Heap* heap, Object** p);

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27 changes: 27 additions & 0 deletions deps/v8/src/objects.cc
Original file line number Diff line number Diff line change
Expand Up @@ -13744,6 +13744,16 @@ void HashTable<Derived, Shape, Key>::Rehash(Key key) {
}
}
}
// Wipe deleted entries.
Heap* heap = GetHeap();
Object* the_hole = heap->the_hole_value();
Object* undefined = heap->undefined_value();
for (uint32_t current = 0; current < capacity; current++) {
if (get(EntryToIndex(current)) == the_hole) {
set(EntryToIndex(current), undefined);
}
}
SetNumberOfDeletedElements(0);
}


Expand Down Expand Up @@ -14656,6 +14666,7 @@ Handle<CompilationCacheTable> CompilationCacheTable::PutRegExp(
void CompilationCacheTable::Age() {
DisallowHeapAllocation no_allocation;
Object* the_hole_value = GetHeap()->the_hole_value();
uint32_t capacity = Capacity();
for (int entry = 0, size = Capacity(); entry < size; entry++) {
int entry_index = EntryToIndex(entry);
int value_index = entry_index + 1;
Expand All @@ -14679,6 +14690,16 @@ void CompilationCacheTable::Age() {
}
}
}
// Wipe deleted entries.
Heap* heap = GetHeap();
Object* the_hole = heap->the_hole_value();
Object* undefined = heap->undefined_value();
for (uint32_t current = 0; current < capacity; current++) {
if (get(EntryToIndex(current)) == the_hole) {
set(EntryToIndex(current), undefined);
}
}
SetNumberOfDeletedElements(0);
}


Expand Down Expand Up @@ -15187,6 +15208,12 @@ Handle<ObjectHashTable> ObjectHashTable::Put(Handle<ObjectHashTable> table,
return table;
}

// Rehash if more than 25% of the entries are deleted entries.
// TODO(jochen): Consider to shrink the fixed array in place.
if ((table->NumberOfDeletedElements() << 1) > table->NumberOfElements()) {
table->Rehash(isolate->factory()->undefined_value());
}

// Check whether the hash table should be extended.
table = EnsureCapacity(table, 1, key);
table->AddEntry(table->FindInsertionEntry(hash), *key, *value);
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2 changes: 1 addition & 1 deletion deps/v8/test/cctest/test-weakmaps.cc
Original file line number Diff line number Diff line change
Expand Up @@ -123,7 +123,7 @@ TEST(Weakness) {
heap->CollectAllGarbage(false);
CHECK_EQ(1, NumberOfWeakCalls);
CHECK_EQ(0, ObjectHashTable::cast(weakmap->table())->NumberOfElements());
CHECK_EQ(2,
CHECK_EQ(0,
ObjectHashTable::cast(weakmap->table())->NumberOfDeletedElements());
}

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4 changes: 2 additions & 2 deletions deps/v8/test/cctest/test-weaksets.cc
Original file line number Diff line number Diff line change
Expand Up @@ -122,8 +122,8 @@ TEST(WeakSet_Weakness) {
heap->CollectAllGarbage(false);
CHECK_EQ(1, NumberOfWeakCalls);
CHECK_EQ(0, ObjectHashTable::cast(weakset->table())->NumberOfElements());
CHECK_EQ(
1, ObjectHashTable::cast(weakset->table())->NumberOfDeletedElements());
CHECK_EQ(0,
ObjectHashTable::cast(weakset->table())->NumberOfDeletedElements());
}


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