Add some debug checks and fix some comments.

Change-Id: I6f0f003b09fea49718eadc59cf35bdb346c585d1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2536636
Commit-Queue: Georg Neis <neis@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71178}

src/objects/dictionary-inl.h

@@ -287,6 +287,7 @@ uint32_t NameDictionaryShape::HashForObject(ReadOnlyRoots roots, Object other) {
 }
 
 bool GlobalDictionaryShape::IsMatch(Handle<Name> key, Object other) {
+  DCHECK(key->IsUniqueName());
   DCHECK(PropertyCell::cast(other).name().IsUniqueName());
   return *key == PropertyCell::cast(other).name();
 }

src/objects/dictionary.h

@@ -60,8 +60,9 @@ class EXPORT_TEMPLATE_DECLARE(V8_EXPORT_PRIVATE) Dictionary
   // Returns the key (slow).
   Object SlowReverseLookup(Object value);
 
-  // Sets the entry to (key, value) pair.
   inline void ClearEntry(InternalIndex entry);
+
+  // Sets the entry to (key, value) pair.
   inline void SetEntry(InternalIndex entry, Object key, Object value,
                        PropertyDetails details);
 

src/objects/hash-table-inl.h

@@ -142,6 +142,7 @@ template <typename Derived, typename Shape>
 InternalIndex HashTable<Derived, Shape>::FindEntry(IsolateRoot isolate,
                                                    ReadOnlyRoots roots, Key key,
                                                    int32_t hash) {
+  DisallowGarbageCollection no_gc;
   uint32_t capacity = Capacity();
   uint32_t count = 1;
   Object undefined = roots.undefined_value();

src/objects/map.h

@@ -177,10 +177,9 @@ using MapHandles = std::vector<Handle<Map>>;
 // +---------------+------------------------------------------------+
 // | TaggedPointer | [instance_descriptors]                         |
 // +****************************************************************+
-// ! TaggedPointer ! [layout_descriptors]                           !
+// ! TaggedPointer ! [layout_descriptor]                            !
 // !               ! Field is only present if compile-time flag     !
 // !               ! FLAG_unbox_double_fields is enabled            !
-// !               ! (basically on 64 bit architectures)            !
 // +****************************************************************+
 // | TaggedPointer | [dependent_code]                               |
 // +---------------+------------------------------------------------+