From 2d810682c878d6017b088e23e3ca5384e7da998d Mon Sep 17 00:00:00 2001
From: "Gang Zhao (Hermes)" <zhaogang@meta.com>
Date: Fri, 22 Nov 2024 16:06:36 -0800
Subject: [PATCH] Pass the pointer of owning object in GCPointer::set() part I
 (#1502)

Summary: Pull Request resolved: https://github.com/facebook/hermes/pull/1502

Differential Revision: D62222257
---
 include/hermes/VM/GCPointer-inline.h | 25 ++++++++++++++++++++++++
 include/hermes/VM/GCPointer.h        | 29 ++++++++++++++++++++++++++--
 2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/include/hermes/VM/GCPointer-inline.h b/include/hermes/VM/GCPointer-inline.h
index fa5f7633ed5..0cfbbb0fc01 100644
--- a/include/hermes/VM/GCPointer-inline.h
+++ b/include/hermes/VM/GCPointer-inline.h
@@ -59,6 +59,31 @@ GCPointerBase::set(PointerBase &base, CompressedPointer ptr, GC &gc) {
   setNoBarrier(ptr);
 }
 
+inline void GCPointerBase::set(
+    PointerBase &base,
+    GCCell *ptr,
+    GC &gc,
+    const GCCell *owningObj) {
+  assert(
+      (!ptr || gc.validPointer(ptr)) &&
+      "Cannot set a GCPointer to an invalid pointer");
+  // Write barrier must happen before the write.
+  gc.writeBarrierForLargeObj(owningObj, this, ptr);
+  setNoBarrier(CompressedPointer::encode(ptr, base));
+}
+
+inline void GCPointerBase::setNonNull(
+    PointerBase &base,
+    GCCell *ptr,
+    GC &gc,
+    const GCCell *owningObj) {
+  assert(
+      gc.validPointer(ptr) && "Cannot set a GCPointer to an invalid pointer");
+  // Write barrier must happen before the write.
+  gc.writeBarrierForLargeObj(owningObj, this, ptr);
+  setNoBarrier(CompressedPointer::encodeNonNull(ptr, base));
+}
+
 inline void GCPointerBase::setNull(GC &gc) {
   gc.snapshotWriteBarrier(this);
   setNoBarrier(CompressedPointer(nullptr));
diff --git a/include/hermes/VM/GCPointer.h b/include/hermes/VM/GCPointer.h
index 09db5f06d87..1336c7c5a30 100644
--- a/include/hermes/VM/GCPointer.h
+++ b/include/hermes/VM/GCPointer.h
@@ -34,7 +34,8 @@ class GCPointerBase : public CompressedPointer {
   class NoBarriers : public std::false_type {};
   class YesBarriers : public std::true_type {};
 
-  /// This must be used to assign a new value to this GCPointer.
+  /// This must be used to assign a new value to this GCPointer. This must not
+  /// be used if it lives in an object that supports large allocation.
   /// \param ptr The memory being pointed to.
   /// \param base The base of ptr.
   /// \param gc Used for write barriers.
@@ -42,6 +43,17 @@ class GCPointerBase : public CompressedPointer {
   inline void set(PointerBase &base, CompressedPointer ptr, GC &gc);
   inline void setNonNull(PointerBase &base, GCCell *ptr, GC &gc);
 
+  /// This must be used to assign a new value to this GCPointer.
+  /// \param ptr The memory being pointed to.
+  /// \param base The base of ptr.
+  /// \param gc Used for write barriers.
+  /// \param owningObj The object that contains this GCPointer, used by the
+  /// writer barriers.
+  inline void
+  set(PointerBase &base, GCCell *ptr, GC &gc, const GCCell *owningObj);
+  inline void
+  setNonNull(PointerBase &base, GCCell *ptr, GC &gc, const GCCell *owningObj);
+
   /// Set this pointer to null. This needs a write barrier in some types of
   /// garbage collectors.
   inline void setNull(GC &gc);
@@ -86,7 +98,8 @@ class GCPointer : public GCPointerBase {
     return vmcast<T>(GCPointerBase::getNonNull(base));
   }
 
-  /// Assign a new value to this GCPointer.
+  /// Assign a new value to this GCPointer. This must not be used if it lives in
+  /// an object that supports large allocation.
   /// \param base The base of ptr.
   /// \param ptr The memory being pointed to.
   /// \param gc Used for write barriers.
@@ -97,6 +110,18 @@ class GCPointer : public GCPointerBase {
     GCPointerBase::setNonNull(base, ptr, gc);
   }
 
+  /// Assign a new value to this GCPointer.
+  /// \param ptr The memory being pointed to.
+  /// \param gc Used for write barriers.
+  /// \param owningObj The object that contains this GCPointer, used by the
+  /// writer barriers.
+  void set(PointerBase &base, T *ptr, GC &gc, const GCCell *owningObj) {
+    GCPointerBase::set(base, ptr, gc, owningObj);
+  }
+  void setNonNull(PointerBase &base, T *ptr, GC &gc, const GCCell *owningObj) {
+    GCPointerBase::setNonNull(base, ptr, gc, owningObj);
+  }
+
   /// Convenience overload of GCPointer::set for other GCPointers.
   void set(PointerBase &base, const GCPointer<T> &ptr, GC &gc) {
     GCPointerBase::set(base, ptr, gc);