[serializer] print reference stack when external reference is unknown

joyeecheung · V8 LUCI CQ · commit 22bee2c92123 · 2021-07-05T07:33:57.000Z
Print the reference stack when V8 is unable to encode an external reference in debug builds so that it's easier for the embedder to track the external reference down. Refs: nodejs/node#38905 Change-Id: Ia86eeb87833d7de0eccc7bc040301c78ddb3240c Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2988831 Reviewed-by: Toon Verwaest <verwaest@chromium.org> Commit-Queue: Joyee Cheung <joyee@igalia.com> Cr-Commit-Position: refs/heads/master@{#75546}
diff --git a/src/snapshot/serializer.cc b/src/snapshot/serializer.cc
@@ -318,6 +318,23 @@ void Serializer::ResolvePendingForwardReference(int forward_reference_id) {
   }
 }
 
+ExternalReferenceEncoder::Value Serializer::EncodeExternalReference(
+    Address addr) {
+  Maybe<ExternalReferenceEncoder::Value> result =
+      external_reference_encoder_.TryEncode(addr);
+  if (result.IsNothing()) {
+#ifdef DEBUG
+    PrintStack(std::cerr);
+#endif
+    void* addr_ptr = reinterpret_cast<void*>(addr);
+    v8::base::OS::PrintError("Unknown external reference %p.\n", addr_ptr);
+    v8::base::OS::PrintError("%s\n",
+                             ExternalReferenceTable::ResolveSymbol(addr_ptr));
+    v8::base::OS::Abort();
+  }
+  return result.FromJust();
+}
+
 void Serializer::RegisterObjectIsPending(Handle<HeapObject> obj) {
   if (*obj == ReadOnlyRoots(isolate()).not_mapped_symbol()) return;
 
diff --git a/src/snapshot/serializer.h b/src/snapshot/serializer.h
@@ -244,9 +244,8 @@ class Serializer : public SerializerDeserializer {
   // Returns true if the given heap object is a bytecode handler code object.
   bool ObjectIsBytecodeHandler(Handle<HeapObject> obj) const;
 
-  ExternalReferenceEncoder::Value EncodeExternalReference(Address addr) {
-    return external_reference_encoder_.Encode(addr);
-  }
+  ExternalReferenceEncoder::Value EncodeExternalReference(Address addr);
+
   Maybe<ExternalReferenceEncoder::Value> TryEncodeExternalReference(
       Address addr) {
     return external_reference_encoder_.TryEncode(addr);
