Detach input buffer in JsrtSourceHolder to keep it alive longer than the ArrayBuffer container object

Author: sethbrenith

lib/Jsrt/ChakraCore.h

@@ -540,8 +540,8 @@ CHAKRA_API
 ///     Requires an active script context.
 ///     </para>
 ///     <para>
-///     The runtime will hold on to the buffer until all instances of any functions created from
-///     the buffer are garbage collected.
+///     The runtime will detach the data from the buffer and hold on to it until all
+///     instances of any functions created from the buffer are garbage collected.
 ///     </para>
 /// </remarks>
 /// <param name="buffer">The serialized script as an ArrayBuffer (preferably ExternalArrayBuffer).</param>

lib/Jsrt/Jsrt.cpp

@@ -3706,7 +3706,7 @@ template <typename TLoadCallback, typename TUnloadCallback>
 JsErrorCode RunSerializedScriptCore(
     TLoadCallback scriptLoadCallback, TUnloadCallback scriptUnloadCallback,
     JsSourceContext scriptLoadSourceContext, // only used by scriptLoadCallback
-    unsigned char *buffer, JsValueRef bufferVal,
+    unsigned char *buffer, Js::ArrayBuffer* bufferVal,
     JsSourceContext sourceContext, const WCHAR *sourceUrl,
     bool parseOnly, JsValueRef *result)
 {
@@ -4939,12 +4939,13 @@ CHAKRA_API JsParseSerialized(
         return JsErrorInvalidArgument;
     }
 
-    byte* buffer = Js::ArrayBuffer::FromVar(bufferVal)->GetBuffer();
+    Js::ArrayBuffer* arrayBuffer = Js::ArrayBuffer::FromVar(bufferVal);
+    byte* buffer = arrayBuffer->GetBuffer();
 
     return RunSerializedScriptCore(
       scriptLoadCallback, DummyScriptUnloadCallback,
       sourceContext,// use the same user provided sourceContext as scriptLoadSourceContext
-      buffer, bufferVal, sourceContext, url, true, result);
+      buffer, arrayBuffer, sourceContext, url, true, result);
 }
 
 CHAKRA_API JsRunSerialized(
@@ -4972,12 +4973,13 @@ CHAKRA_API JsRunSerialized(
         return JsErrorInvalidArgument;
     }
 
-    byte* buffer = Js::ArrayBuffer::FromVar(bufferVal)->GetBuffer();
+    Js::ArrayBuffer* arrayBuffer = Js::ArrayBuffer::FromVar(bufferVal);
+    byte* buffer = arrayBuffer->GetBuffer();
 
     return RunSerializedScriptCore(
         scriptLoadCallback, DummyScriptUnloadCallback,
         sourceContext, // use the same user provided sourceContext as scriptLoadSourceContext
-        buffer, bufferVal, sourceContext, url, false, result);
+        buffer, arrayBuffer, sourceContext, url, false, result);
 }
 
 CHAKRA_API JsCreatePromise(_Out_ JsValueRef *promise, _Out_ JsValueRef *resolve, _Out_ JsValueRef *reject)

lib/Jsrt/JsrtSourceHolder.cpp

@@ -299,7 +299,6 @@ namespace Js
             this->mappedSource = nullptr;
         }
         this->mappedScriptValue = nullptr;
-        this->mappedSerializedScriptValue = nullptr;
 
         // Don't allow load or unload again after told to unload.
         scriptLoadCallback = nullptr;

lib/Jsrt/JsrtSourceHolder.h

@@ -19,7 +19,7 @@ namespace Js
 
 #ifndef NTBUILD
         Field(JsValueRef) mappedScriptValue;
-        Field(JsValueRef) mappedSerializedScriptValue;
+        Field(DetachedStateBase*) mappedSerializedScriptValue;
 #endif
         Field(utf8char_t const *) mappedSource;
         Field(size_t) mappedSourceByteLength;
@@ -46,13 +46,13 @@ namespace Js
         JsrtSourceHolder(_In_ TLoadCallback scriptLoadCallback,
             _In_ TUnloadCallback scriptUnloadCallback,
             _In_ JsSourceContext sourceContext,
-            JsValueRef serializedScriptValue = nullptr) :
+            Js::ArrayBuffer* serializedScriptValue = nullptr) :
             scriptLoadCallback(scriptLoadCallback),
             scriptUnloadCallback(scriptUnloadCallback),
             sourceContext(sourceContext),
 #ifndef NTBUILD
             mappedScriptValue(nullptr),
-            mappedSerializedScriptValue(serializedScriptValue),
+            mappedSerializedScriptValue(serializedScriptValue == nullptr ? nullptr : serializedScriptValue->DetachAndGetState()),
 #endif
             mappedSourceByteLength(0),
             mappedSource(nullptr)
@@ -89,6 +89,15 @@ namespace Js
 
         virtual void Dispose(bool isShutdown) override
         {
+#ifndef NTBUILD
+            if (this->mappedSerializedScriptValue != nullptr)
+            {
+                // We have to extend the buffer data's lifetime until Dispose because
+                // it might be used during finalization of other objects, such as
+                // FunctionEntryPointInfo which wants to log its name.
+                this->mappedSerializedScriptValue->CleanUp();
+            }
+#endif
         }
 
         virtual void Mark(Recycler * recycler) override