From 55be65da1597926416e5546d95ac723419e4c8ef Mon Sep 17 00:00:00 2001
From: Michael Lippautz <mlippautz@chromium.org>
Date: Fri, 11 Oct 2019 13:58:02 +0200
Subject: [PATCH] api: Rely on v8::Data base type for garbage collection
 support

Use v8::Data as basetype for managed objects that can integrate with
v8::EmbedderHeapTracer.

Bug: v8:9841
Change-Id: Id3e06701207a23870cea89e1d7d334c48fcd3006
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1856002
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64283}
---
 include/v8.h                              | 9 +++++----
 src/api/api.cc                            | 9 +++++++++
 test/cctest/heap/test-embedder-tracing.cc | 2 +-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/include/v8.h b/include/v8.h
index 667a487915..1387f74715 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -1275,9 +1275,8 @@ class V8_EXPORT SealHandleScope {
 
 // --- Special objects ---
 
-
 /**
- * The superclass of values and API object templates.
+ * The superclass of objects that can reside on V8's heap.
  */
 class V8_EXPORT Data {
  private:
@@ -1424,7 +1423,7 @@ class V8_EXPORT UnboundScript {
 /**
  * A compiled JavaScript module, not yet tied to a Context.
  */
-class V8_EXPORT UnboundModuleScript {
+class V8_EXPORT UnboundModuleScript : public Data {
   // Only used as a container for code caching.
 };
 
@@ -1447,7 +1446,7 @@ class V8_EXPORT Location {
 /**
  * A compiled JavaScript module.
  */
-class V8_EXPORT Module {
+class V8_EXPORT Module : public Data {
  public:
   /**
    * The different states a module can be in.
@@ -7605,7 +7604,9 @@ class V8_EXPORT EmbedderHeapTracer {
   virtual void RegisterV8References(
       const std::vector<std::pair<void*, void*> >& embedder_fields) = 0;
 
+  V8_DEPRECATE_SOON("Use version taking TracedReferenceBase<v8::Data> argument")
   void RegisterEmbedderReference(const TracedReferenceBase<v8::Value>& ref);
+  void RegisterEmbedderReference(const TracedReferenceBase<v8::Data>& ref);
 
   /**
    * Called at the beginning of a GC cycle.
diff --git a/src/api/api.cc b/src/api/api.cc
index 7088a26841..0d80f986f1 100644
--- a/src/api/api.cc
+++ b/src/api/api.cc
@@ -10557,6 +10557,15 @@ void EmbedderHeapTracer::DecreaseAllocatedSize(size_t bytes) {
   }
 }
 
+void EmbedderHeapTracer::RegisterEmbedderReference(
+    const TracedReferenceBase<v8::Data>& ref) {
+  if (ref.IsEmpty()) return;
+
+  i::Heap* const heap = reinterpret_cast<i::Isolate*>(isolate_)->heap();
+  heap->RegisterExternallyReferencedObject(
+      reinterpret_cast<i::Address*>(ref.val_));
+}
+
 void EmbedderHeapTracer::RegisterEmbedderReference(
     const TracedReferenceBase<v8::Value>& ref) {
   if (ref.IsEmpty()) return;
diff --git a/test/cctest/heap/test-embedder-tracing.cc b/test/cctest/heap/test-embedder-tracing.cc
index 11f154f936..8ff4acc05b 100644
--- a/test/cctest/heap/test-embedder-tracing.cc
+++ b/test/cctest/heap/test-embedder-tracing.cc
@@ -62,7 +62,7 @@ class TestEmbedderHeapTracer final : public v8::EmbedderHeapTracer {
 
   bool AdvanceTracing(double deadline_in_ms) final {
     for (auto global : to_register_with_v8_) {
-      RegisterEmbedderReference(global->As<v8::Value>());
+      RegisterEmbedderReference(global->As<v8::Data>());
     }
     to_register_with_v8_.clear();
     return true;