heap: Limit HeapDeque to no inline buffers

There are no usages of HeapDeque that use an inline buffer.

Bug: 986235
Change-Id: I72d2c173690b5498cbb0726ae7521fdea2756a84
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2032117Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#737308}

third_party/blink/renderer/platform/heap/gc_info.h

@@ -130,7 +130,7 @@ template <typename ValueArg, wtf_size_t inlineCapacity>
 class HeapListHashSetAllocator;
 template <typename T, wtf_size_t inlineCapacity>
 class HeapVector;
-template <typename T, wtf_size_t inlineCapacity>
+template <typename T>
 class HeapDeque;
 template <typename T, typename U, typename V>
 class HeapHashCountedSet;
@@ -154,9 +154,9 @@ struct GCInfoTrait<HeapListHashSet<T, inlineCapacity, U>>
 template <typename T, wtf_size_t inlineCapacity>
 struct GCInfoTrait<HeapVector<T, inlineCapacity>>
     : public GCInfoTrait<Vector<T, inlineCapacity, HeapAllocator>> {};
-template <typename T, wtf_size_t inlineCapacity>
-struct GCInfoTrait<HeapDeque<T, inlineCapacity>>
-    : public GCInfoTrait<Deque<T, inlineCapacity, HeapAllocator>> {};
+template <typename T>
+struct GCInfoTrait<HeapDeque<T>>
+    : public GCInfoTrait<Deque<T, 0, HeapAllocator>> {};
 template <typename T, typename U, typename V>
 struct GCInfoTrait<HeapHashCountedSet<T, U, V>>
     : public GCInfoTrait<HashCountedSet<T, U, V, HeapAllocator>> {};

third_party/blink/renderer/platform/heap/heap_allocator.h

@@ -657,14 +657,13 @@ class HeapVector : public Vector<T, inlineCapacity, HeapAllocator> {
   }
 };
 
-template <typename T, wtf_size_t inlineCapacity = 0>
-class HeapDeque : public Deque<T, inlineCapacity, HeapAllocator> {
+template <typename T>
+class HeapDeque : public Deque<T, 0, HeapAllocator> {
   IS_GARBAGE_COLLECTED_CONTAINER_TYPE();
   DISALLOW_NEW();
 
   static void CheckType() {
-    static_assert(
-        std::is_trivially_destructible<HeapDeque>::value || inlineCapacity,
+    static_assert(std::is_trivially_destructible<HeapDeque>::value,
                   "HeapDeque must be trivially destructible.");
     static_assert(
         IsAllowedInContainer<T>::value,
@@ -677,35 +676,27 @@ class HeapDeque : public Deque<T, inlineCapacity, HeapAllocator> {
  public:
   template <typename>
   static void* AllocateObject(size_t size) {
-    // On-heap HeapDeques generally should not have inline capacity, but it is
-    // hard to avoid when using a type alias. Hence we only disallow the
-    // VectorTraits<T>::kNeedsDestruction case for now.
-    static_assert(inlineCapacity == 0 || !VectorTraits<T>::kNeedsDestruction,
-                  "on-heap HeapDeque<> should not have an inline capacity");
-    return ThreadHeap::Allocate<HeapDeque<T, inlineCapacity>>(size);
+    return ThreadHeap::Allocate<HeapDeque<T>>(size);
   }
 
   HeapDeque() { CheckType(); }
 
-  explicit HeapDeque(wtf_size_t size)
-      : Deque<T, inlineCapacity, HeapAllocator>(size) {
+  explicit HeapDeque(wtf_size_t size) : Deque<T, 0, HeapAllocator>(size) {
     CheckType();
   }
 
   HeapDeque(wtf_size_t size, const T& val)
-      : Deque<T, inlineCapacity, HeapAllocator>(size, val) {
+      : Deque<T, 0, HeapAllocator>(size, val) {
     CheckType();
   }
 
   HeapDeque& operator=(const HeapDeque& other) {
     HeapDeque<T> copy(other);
-    Deque<T, inlineCapacity, HeapAllocator>::Swap(copy);
+    Deque<T, 0, HeapAllocator>::Swap(copy);
     return *this;
   }
 
-  template <wtf_size_t otherCapacity>
-  HeapDeque(const HeapDeque<T, otherCapacity>& other)
-      : Deque<T, inlineCapacity, HeapAllocator>(other) {}
+  HeapDeque(const HeapDeque<T>& other) : Deque<T, 0, HeapAllocator>(other) {}
 };
 
 }  // namespace blink
@@ -753,8 +744,8 @@ struct VectorTraits<blink::HeapVector<T, 0>>
 };
 
 template <typename T>
-struct VectorTraits<blink::HeapDeque<T, 0>>
-    : VectorTraitsBase<blink::HeapDeque<T, 0>> {
+struct VectorTraits<blink::HeapDeque<T>>
+    : VectorTraitsBase<blink::HeapDeque<T>> {
   STATIC_ONLY(VectorTraits);
   static const bool kNeedsDestruction = false;
   static const bool kCanInitializeWithMemset = true;
@@ -774,18 +765,6 @@ struct VectorTraits<blink::HeapVector<T, inlineCapacity>>
   static const bool kCanMoveWithMemcpy = VectorTraits<T>::kCanMoveWithMemcpy;
 };
 
-template <typename T, wtf_size_t inlineCapacity>
-struct VectorTraits<blink::HeapDeque<T, inlineCapacity>>
-    : VectorTraitsBase<blink::HeapDeque<T, inlineCapacity>> {
-  STATIC_ONLY(VectorTraits);
-  static const bool kNeedsDestruction = VectorTraits<T>::kNeedsDestruction;
-  static const bool kCanInitializeWithMemset =
-      VectorTraits<T>::kCanInitializeWithMemset;
-  static const bool kCanClearUnusedSlotsWithMemset =
-      VectorTraits<T>::kCanClearUnusedSlotsWithMemset;
-  static const bool kCanMoveWithMemcpy = VectorTraits<T>::kCanMoveWithMemcpy;
-};
-
 template <typename T>
 struct HashTraits<blink::Member<T>> : SimpleClassHashTraits<blink::Member<T>> {
   STATIC_ONLY(HashTraits);

third_party/blink/renderer/platform/heap/heap_test.cc

@@ -2243,9 +2243,9 @@ class Container final : public GarbageCollected<Container> {
   HeapVector<Member<IntWrapper>, 2> vector;
   HeapVector<PairWrappedUnwrapped, 2> vector_wu;
   HeapVector<PairUnwrappedWrapped, 2> vector_uw;
-  HeapDeque<Member<IntWrapper>, 0> deque;
-  HeapDeque<PairWrappedUnwrapped, 0> deque_wu;
-  HeapDeque<PairUnwrappedWrapped, 0> deque_uw;
+  HeapDeque<Member<IntWrapper>> deque;
+  HeapDeque<PairWrappedUnwrapped> deque_wu;
+  HeapDeque<PairUnwrappedWrapped> deque_uw;
   void Trace(blink::Visitor* visitor) {
     visitor->Trace(map);
     visitor->Trace(set);
@@ -2407,9 +2407,9 @@ TEST_F(HeapTest, HeapVectorOnStackLargeObjectPageSized) {
   ConservativelyCollectGarbage();
 }
 
-template <typename T, wtf_size_t inlineCapacity, typename U>
-bool DequeContains(HeapDeque<T, inlineCapacity>& deque, U u) {
-  typedef typename HeapDeque<T, inlineCapacity>::iterator iterator;
+template <typename T, typename U>
+bool DequeContains(HeapDeque<T>& deque, U u) {
+  typedef typename HeapDeque<T>::iterator iterator;
   for (iterator it = deque.begin(); it != deque.end(); ++it) {
     if (*it == u)
       return true;
@@ -2428,12 +2428,12 @@ TEST_F(HeapTest, HeapCollectionTypes) {
   typedef HeapHashCountedSet<Member<IntWrapper>> MemberCountedSet;
 
   typedef HeapVector<Member<IntWrapper>, 2> MemberVector;
-  typedef HeapDeque<Member<IntWrapper>, 0> MemberDeque;
+  typedef HeapDeque<Member<IntWrapper>> MemberDeque;
 
   typedef HeapVector<PairWrappedUnwrapped, 2> VectorWU;
   typedef HeapVector<PairUnwrappedWrapped, 2> VectorUW;
-  typedef HeapDeque<PairWrappedUnwrapped, 0> DequeWU;
-  typedef HeapDeque<PairUnwrappedWrapped, 0> DequeUW;
+  typedef HeapDeque<PairWrappedUnwrapped> DequeWU;
+  typedef HeapDeque<PairUnwrappedWrapped> DequeUW;
 
   Persistent<MemberMember> member_member = MakeGarbageCollected<MemberMember>();
   Persistent<MemberMember> member_member2 =
@@ -4085,8 +4085,8 @@ TEST_F(HeapTest, EmbeddedInDeque) {
   ClearOutOldGarbage();
   SimpleFinalizedObject::destructor_calls_ = 0;
   {
-    Persistent<HeapDeque<VectorObject, 2>> inline_deque =
-        MakeGarbageCollected<HeapDeque<VectorObject, 2>>();
+    Persistent<HeapDeque<VectorObject>> inline_deque =
+        MakeGarbageCollected<HeapDeque<VectorObject>>();
     Persistent<HeapDeque<VectorObject>> outline_deque =
         MakeGarbageCollected<HeapDeque<VectorObject>>();
     VectorObject i1, i2;

third_party/blink/renderer/platform/heap/threading_traits.h

@@ -154,7 +154,7 @@ template <typename T, typename U, typename V>
 class HeapHashSet;
 template <typename T, wtf_size_t inlineCapacity>
 class HeapVector;
-template <typename T, wtf_size_t inlineCapacity>
+template <typename T>
 class HeapDeque;
 template <typename T, typename U, typename V>
 class HeapHashCountedSet;
@@ -174,9 +174,9 @@ struct ThreadingTrait<HeapVector<T, inlineCapacity>>
     : public ThreadingTrait<Vector<T, inlineCapacity, HeapAllocator>> {
   STATIC_ONLY(ThreadingTrait);
 };
-template <typename T, size_t inlineCapacity>
-struct ThreadingTrait<HeapDeque<T, inlineCapacity>>
-    : public ThreadingTrait<Deque<T, inlineCapacity, HeapAllocator>> {
+template <typename T>
+struct ThreadingTrait<HeapDeque<T>>
+    : public ThreadingTrait<Deque<T, 0, HeapAllocator>> {
   STATIC_ONLY(ThreadingTrait);
 };
 template <typename T, typename U, typename V>

third_party/blink/renderer/platform/wtf/deque.h

@@ -685,38 +685,13 @@ Deque<T, inlineCapacity, Allocator>::Trace(VisitorDispatcher visitor) {
            }}))
     return;
 
+  static_assert(inlineCapacity == 0,
+                "Heap allocated Deque should not use inline buffer");
   static_assert(Allocator::kIsGarbageCollected,
                 "Garbage collector must be enabled.");
-  if (buffer_.HasOutOfLineBuffer()) {
+  DCHECK(buffer_.HasOutOfLineBuffer() || IsEmpty());
   Allocator::TraceVectorBacking(visitor, buffer_.Buffer(),
                                 buffer_.BufferSlot());
-  } else {
-    Allocator::TraceVectorBacking(visitor, static_cast<T*>(nullptr),
-                                  buffer_.BufferSlot());
-    const T* buffer_begin = buffer_.Buffer();
-    const T* end = buffer_begin + end_;
-    if (IsTraceableInCollectionTrait<VectorTraits<T>>::value) {
-      if (start_ <= end_) {
-        for (const T* buffer_entry = buffer_begin + start_; buffer_entry != end;
-             buffer_entry++) {
-          Allocator::template Trace<T, VectorTraits<T>>(
-              visitor, *const_cast<T*>(buffer_entry));
-        }
-      } else {
-        for (const T* buffer_entry = buffer_begin; buffer_entry != end;
-             buffer_entry++) {
-          Allocator::template Trace<T, VectorTraits<T>>(
-              visitor, *const_cast<T*>(buffer_entry));
-        }
-        const T* buffer_end = buffer_.Buffer() + buffer_.capacity();
-        for (const T* buffer_entry = buffer_begin + start_;
-             buffer_entry != buffer_end; buffer_entry++) {
-          Allocator::template Trace<T, VectorTraits<T>>(
-              visitor, *const_cast<T*>(buffer_entry));
-        }
-      }
-    }
-  }
 }
 
 template <typename T, wtf_size_t inlineCapacity, typename Allocator>