[heap] Skip write barrier Smi check for known HeapObjects

Add HeapObject overloads for MarkingBarrier, GenerationalBarrier and
WriteBarrierForCode, which the compiler automatically prefers if a
setter's type is a subclass of HeapObject. These overloads can skip
the IsHeapObject check, providing maybe a small performance boost and
I measure a ~4.5kB binary size reduction in libv8.so

Change-Id: Ia65ff8425ae4895da406587101c7813fe6bf5a2b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1958055
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65395}

src/heap/heap-write-barrier-inl.h

@@ -132,9 +132,12 @@ inline void MarkingBarrierInternal(HeapObject object, Address slot,
 inline void WriteBarrierForCode(Code host, RelocInfo* rinfo, Object value) {
   DCHECK(!HasWeakHeapObjectTag(value));
   if (!value.IsHeapObject()) return;
-  HeapObject object = HeapObject::cast(value);
-  GenerationalBarrierForCode(host, rinfo, object);
-  MarkingBarrierForCode(host, rinfo, object);
+  WriteBarrierForCode(host, rinfo, HeapObject::cast(value));
+}
+
+inline void WriteBarrierForCode(Code host, RelocInfo* rinfo, HeapObject value) {
+  GenerationalBarrierForCode(host, rinfo, value);
+  MarkingBarrierForCode(host, rinfo, value);
 }
 
 inline void WriteBarrierForCode(Code host) {
@@ -144,9 +147,15 @@ inline void WriteBarrierForCode(Code host) {
 inline void GenerationalBarrier(HeapObject object, ObjectSlot slot,
                                 Object value) {
   if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) return;
-  DCHECK(!HasWeakHeapObjectTag(*slot));
   DCHECK(!HasWeakHeapObjectTag(value));
   if (!value.IsHeapObject()) return;
+  GenerationalBarrier(object, slot, HeapObject::cast(value));
+}
+
+inline void GenerationalBarrier(HeapObject object, ObjectSlot slot,
+                                HeapObject value) {
+  if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) return;
+  DCHECK(!HasWeakHeapObjectTag(*slot));
   heap_internals::GenerationalBarrierInternal(object, slot.address(),
                                               HeapObject::cast(value));
 }
@@ -181,9 +190,15 @@ inline void GenerationalBarrierForCode(Code host, RelocInfo* rinfo,
 
 inline void MarkingBarrier(HeapObject object, ObjectSlot slot, Object value) {
   if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) return;
-  DCHECK_IMPLIES(slot.address() != kNullAddress, !HasWeakHeapObjectTag(*slot));
   DCHECK(!HasWeakHeapObjectTag(value));
   if (!value.IsHeapObject()) return;
+  MarkingBarrier(object, slot, HeapObject::cast(value));
+}
+
+inline void MarkingBarrier(HeapObject object, ObjectSlot slot,
+                           HeapObject value) {
+  if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) return;
+  DCHECK_IMPLIES(slot.address() != kNullAddress, !HasWeakHeapObjectTag(*slot));
   heap_internals::MarkingBarrierInternal(object, slot.address(),
                                          HeapObject::cast(value));
 }

src/heap/heap-write-barrier.h

@@ -22,10 +22,12 @@ class EphemeronHashTable;
 
 // Combined write barriers.
 void WriteBarrierForCode(Code host, RelocInfo* rinfo, Object value);
+void WriteBarrierForCode(Code host, RelocInfo* rinfo, HeapObject value);
 void WriteBarrierForCode(Code host);
 
 // Generational write barrier.
 void GenerationalBarrier(HeapObject object, ObjectSlot slot, Object value);
+void GenerationalBarrier(HeapObject object, ObjectSlot slot, HeapObject value);
 void GenerationalBarrier(HeapObject object, MaybeObjectSlot slot,
                          MaybeObject value);
 void GenerationalEphemeronKeyBarrier(EphemeronHashTable table, ObjectSlot slot,
@@ -34,6 +36,7 @@ void GenerationalBarrierForCode(Code host, RelocInfo* rinfo, HeapObject object);
 
 // Marking write barrier.
 void MarkingBarrier(HeapObject object, ObjectSlot slot, Object value);
+void MarkingBarrier(HeapObject object, ObjectSlot slot, HeapObject value);
 void MarkingBarrier(HeapObject object, MaybeObjectSlot slot, MaybeObject value);
 void MarkingBarrierForCode(Code host, RelocInfo* rinfo, HeapObject object);