deps: update V8 to 6.4.388.40

PR-URL: https://github.com/nodejs/node/pull/17489
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/deps/v8/src/visitors.h b/deps/v8/src/visitors.h
index baf989182b..7696df8faf 100644
--- a/deps/v8/src/visitors.h
+++ b/deps/v8/src/visitors.h
@@ -10,6 +10,7 @@
 namespace v8 {
 namespace internal {
 
+class CodeDataContainer;
 class Object;
 
 #define ROOT_ID_LIST(V)                                                    \
@@ -75,6 +76,44 @@ class RootVisitor BASE_EMBEDDED {
   virtual void Synchronize(VisitorSynchronization::SyncTag tag) {}
 };
 
+// Abstract base class for visiting, and optionally modifying, the
+// pointers contained in Objects. Used in GC and serialization/deserialization.
+class ObjectVisitor BASE_EMBEDDED {
+ public:
+  virtual ~ObjectVisitor() {}
+
+  // Visits a contiguous arrays of pointers in the half-open range
+  // [start, end). Any or all of the values may be modified on return.
+  virtual void VisitPointers(HeapObject* host, Object** start,
+                             Object** end) = 0;
+
+  // Handy shorthand for visiting a single pointer.
+  virtual void VisitPointer(HeapObject* host, Object** p) {
+    VisitPointers(host, p, p + 1);
+  }
+
+  // To allow lazy clearing of inline caches the visitor has
+  // a rich interface for iterating over Code objects ...
+
+  // Visits a code target in the instruction stream.
+  virtual void VisitCodeTarget(Code* host, RelocInfo* rinfo);
+
+  // Visits a runtime entry in the instruction stream.
+  virtual void VisitRuntimeEntry(Code* host, RelocInfo* rinfo) {}
+
+  // Visit pointer embedded into a code object.
+  virtual void VisitEmbeddedPointer(Code* host, RelocInfo* rinfo);
+
+  // Visits an external reference embedded into a code object.
+  virtual void VisitExternalReference(Code* host, RelocInfo* rinfo) {}
+
+  // Visits an external reference.
+  virtual void VisitExternalReference(Foreign* host, Address* p) {}
+
+  // Visits an (encoded) internal reference.
+  virtual void VisitInternalReference(Code* host, RelocInfo* rinfo) {}
+};
+
 }  // namespace internal
 }  // namespace v8