[in-place weak refs] Make the WeakArrayList API more generic.

(Pre-work for adding special-purpose data structures as subclasses.)

BUG=v8:7308

Change-Id: I82a5a96e18c3321e9d5b783642516ff869b45f27
Reviewed-on: https://chromium-review.googlesource.com/1084474
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53482}

src/heap/heap.cc

@@ -5108,8 +5108,10 @@ void Heap::AddRetainedMap(Handle<Map> map) {
   if (array->IsFull()) {
     CompactRetainedMaps(*array);
   }
-  array =
-      WeakArrayList::Add(array, map, Smi::FromInt(FLAG_retain_maps_for_n_gc));
+  array = WeakArrayList::AddToEnd(array, MaybeObjectHandle::Weak(map));
+  array = WeakArrayList::AddToEnd(
+      array,
+      MaybeObjectHandle(Smi::FromInt(FLAG_retain_maps_for_n_gc), isolate()));
   if (*array != retained_maps()) {
     set_retained_maps(*array);
   }

src/objects.cc

@@ -10372,15 +10372,14 @@ Handle<ArrayList> ArrayList::EnsureSpace(Handle<ArrayList> array, int length) {
 }
 
 // static
-Handle<WeakArrayList> WeakArrayList::Add(Handle<WeakArrayList> array,
-                                         Handle<HeapObject> obj1, Smi* obj2) {
+Handle<WeakArrayList> WeakArrayList::AddToEnd(Handle<WeakArrayList> array,
+                                              MaybeObjectHandle value) {
   int length = array->length();
-  array = EnsureSpace(array, length + 2);
+  array = EnsureSpace(array, length + 1);
   // Check that GC didn't remove elements from the array.
   DCHECK_EQ(array->length(), length);
-  array->Set(length, HeapObjectReference::Weak(*obj1));
-  array->Set(length + 1, MaybeObject::FromSmi(obj2));
-  array->set_length(length + 2);
+  array->Set(length, *value);
+  array->set_length(length + 1);
   return array;
 }
 

src/objects/fixed-array.h

@@ -315,13 +315,13 @@ class WeakArrayList : public HeapObject {
   DECL_VERIFIER(WeakArrayList)
   DECL_PRINTER(WeakArrayList)
 
-  static Handle<WeakArrayList> Add(Handle<WeakArrayList> array,
-                                   Handle<HeapObject> obj1, Smi* obj2);
+  static Handle<WeakArrayList> AddToEnd(Handle<WeakArrayList> array,
+                                        MaybeObjectHandle value);
 
   inline MaybeObject* Get(int index) const;
 
   // Set the element at index to obj. The underlying array must be large enough.
-  // If you need to grow the WeakArrayList, use the static Add() methods
+  // If you need to grow the WeakArrayList, use the static AddToEnd() method
   // instead.
   inline void Set(int index, MaybeObject* value,
                   WriteBarrierMode mode = UPDATE_WRITE_BARRIER);

test/cctest/heap/test-weak-references.cc

@@ -453,16 +453,24 @@ TEST(WeakArrayListBasic) {
     Handle<FixedArray> index6 = factory->NewFixedArray(1);
     index6->set(0, Smi::FromInt(2019));
 
-    array = WeakArrayList::Add(array, index0, Smi::FromInt(1));
+    array = WeakArrayList::AddToEnd(array, MaybeObjectHandle::Weak(index0));
+    array = WeakArrayList::AddToEnd(
+        array, MaybeObjectHandle(Smi::FromInt(1), isolate));
     CHECK_EQ(array->length(), 2);
 
-    array = WeakArrayList::Add(array, index2, Smi::FromInt(3));
+    array = WeakArrayList::AddToEnd(array, MaybeObjectHandle::Weak(index2));
+    array = WeakArrayList::AddToEnd(
+        array, MaybeObjectHandle(Smi::FromInt(3), isolate));
     CHECK_EQ(array->length(), 4);
 
-    array = WeakArrayList::Add(array, index4, Smi::FromInt(5));
+    array = WeakArrayList::AddToEnd(array, MaybeObjectHandle::Weak(index4));
+    array = WeakArrayList::AddToEnd(
+        array, MaybeObjectHandle(Smi::FromInt(5), isolate));
     CHECK_EQ(array->length(), 6);
 
-    array = WeakArrayList::Add(array, index6, Smi::FromInt(7));
+    array = WeakArrayList::AddToEnd(array, MaybeObjectHandle::Weak(index6));
+    array = WeakArrayList::AddToEnd(
+        array, MaybeObjectHandle(Smi::FromInt(7), isolate));
     CHECK_EQ(array->length(), 8);
 
     CHECK(heap->InNewSpace(*array));