Bug 1599416 - Part 7: Remove unused lazyArrayBuffers table. r=mgaudet

Entries are never added to `lazyArrayBuffers` resp. `lazyArrayBuffers` isn't
even allocated anymore.

Differential Revision: https://phabricator.services.mozilla.com/D54711

--HG--
extra : moz-landing-system : lando

js/public/MemoryMetrics.h

@@ -730,7 +730,6 @@ struct RealmStats {
   MACRO(Other, MallocHeap, realmObject)                       \
   MACRO(Other, MallocHeap, realmTables)                       \
   MACRO(Other, MallocHeap, innerViewsTable)                   \
-  MACRO(Other, MallocHeap, lazyArrayBuffersTable)             \
   MACRO(Other, MallocHeap, objectMetadataTable)               \
   MACRO(Other, MallocHeap, savedStacksSet)                    \
   MACRO(Other, MallocHeap, varNamesSet)                       \

js/src/builtin/TypedObject.cpp

@@ -1515,13 +1515,6 @@ uint8_t* TypedObject::typedMemBase() const {
 
 bool TypedObject::isAttached() const {
   if (is<InlineTransparentTypedObject>()) {
-    ObjectWeakMap* table = ObjectRealm::get(this).lazyArrayBuffers.get();
-    if (table) {
-      JSObject* buffer = table->lookup(this);
-      if (buffer) {
-        return !buffer->as<ArrayBufferObject>().isDetached();
-      }
-    }
     return true;
   }
   if (is<InlineOpaqueTypedObject>()) {

js/src/vm/MemoryMetrics.cpp

@@ -240,9 +240,9 @@ static void StatsRealmCallback(JSContext* cx, void* data,
       &realmStats.typeInferenceArrayTypeTables,
       &realmStats.typeInferenceObjectTypeTables, &realmStats.realmObject,
       &realmStats.realmTables, &realmStats.innerViewsTable,
-      &realmStats.lazyArrayBuffersTable, &realmStats.objectMetadataTable,
-      &realmStats.savedStacksSet, &realmStats.varNamesSet,
-      &realmStats.nonSyntacticLexicalScopesTable, &realmStats.jitRealm);
+      &realmStats.objectMetadataTable, &realmStats.savedStacksSet,
+      &realmStats.varNamesSet, &realmStats.nonSyntacticLexicalScopesTable,
+      &realmStats.jitRealm);
 }
 
 static void StatsArenaCallback(JSRuntime* rt, void* data, gc::Arena* arena,

js/src/vm/Realm.cpp

@@ -276,10 +276,6 @@ void Realm::traceGlobal(JSTracer* trc) {
 }
 
 void ObjectRealm::trace(JSTracer* trc) {
-  if (lazyArrayBuffers) {
-    lazyArrayBuffers->trace(trc);
-  }
-
   if (objectMetadataTable) {
     objectMetadataTable->trace(trc);
   }
@@ -324,10 +320,6 @@ void Realm::traceRoots(JSTracer* trc,
 }
 
 void ObjectRealm::finishRoots() {
-  if (lazyArrayBuffers) {
-    lazyArrayBuffers->clear();
-  }
-
   if (objectMetadataTable) {
     objectMetadataTable->clear();
   }
@@ -739,14 +731,10 @@ void Realm::collectCodeCoverageInfo(JSScript* script, const char* name) {
 
 void ObjectRealm::addSizeOfExcludingThis(
     mozilla::MallocSizeOf mallocSizeOf, size_t* innerViewsArg,
-    size_t* lazyArrayBuffersArg, size_t* objectMetadataTablesArg,
+    size_t* objectMetadataTablesArg,
     size_t* nonSyntacticLexicalEnvironmentsArg) {
   *innerViewsArg += innerViews.sizeOfExcludingThis(mallocSizeOf);
 
-  if (lazyArrayBuffers) {
-    *lazyArrayBuffersArg += lazyArrayBuffers->sizeOfIncludingThis(mallocSizeOf);
-  }
-
   if (objectMetadataTable) {
     *objectMetadataTablesArg +=
         objectMetadataTable->sizeOfIncludingThis(mallocSizeOf);
@@ -761,10 +749,9 @@ void ObjectRealm::addSizeOfExcludingThis(
 void Realm::addSizeOfIncludingThis(
     mozilla::MallocSizeOf mallocSizeOf, size_t* tiAllocationSiteTables,
     size_t* tiArrayTypeTables, size_t* tiObjectTypeTables, size_t* realmObject,
-    size_t* realmTables, size_t* innerViewsArg, size_t* lazyArrayBuffersArg,
-    size_t* objectMetadataTablesArg, size_t* savedStacksSet,
-    size_t* varNamesSet, size_t* nonSyntacticLexicalEnvironmentsArg,
-    size_t* jitRealm) {
+    size_t* realmTables, size_t* innerViewsArg, size_t* objectMetadataTablesArg,
+    size_t* savedStacksSet, size_t* varNamesSet,
+    size_t* nonSyntacticLexicalEnvironmentsArg, size_t* jitRealm) {
   *realmObject += mallocSizeOf(this);
   objectGroups_.addSizeOfExcludingThis(mallocSizeOf, tiAllocationSiteTables,
                                        tiArrayTypeTables, tiObjectTypeTables,
@@ -772,7 +759,7 @@ void Realm::addSizeOfIncludingThis(
   wasm.addSizeOfExcludingThis(mallocSizeOf, realmTables);
 
   objects_.addSizeOfExcludingThis(mallocSizeOf, innerViewsArg,
-                                  lazyArrayBuffersArg, objectMetadataTablesArg,
+                                  objectMetadataTablesArg,
                                   nonSyntacticLexicalEnvironmentsArg);
 
   *savedStacksSet += savedStacks_.sizeOfExcludingThis(mallocSizeOf);

js/src/vm/Realm.h

@@ -248,11 +248,6 @@ class ObjectRealm {
   // Map from array buffers to views sharing that storage.
   JS::WeakCache<js::InnerViewTable> innerViews;
 
-  // Inline transparent typed objects do not initially have an array buffer,
-  // but can have that buffer created lazily if it is accessed later. This
-  // table manages references from such typed objects to their buffers.
-  js::UniquePtr<js::ObjectWeakMap> lazyArrayBuffers;
-
   // Keep track of the metadata objects which can be associated with each JS
   // object. Both keys and values are in this realm.
   js::UniquePtr<js::ObjectWeakMap> objectMetadataTable;
@@ -276,7 +271,6 @@ class ObjectRealm {
 
   void addSizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf,
                               size_t* innerViewsArg,
-                              size_t* lazyArrayBuffersArg,
                               size_t* objectMetadataTablesArg,
                               size_t* nonSyntacticLexicalEnvironmentsArg);
 
@@ -467,13 +461,15 @@ class JS::Realm : public JS::shadow::Realm {
   void destroy(JSFreeOp* fop);
   void clearTables();
 
-  void addSizeOfIncludingThis(
-      mozilla::MallocSizeOf mallocSizeOf, size_t* tiAllocationSiteTables,
-      size_t* tiArrayTypeTables, size_t* tiObjectTypeTables,
-      size_t* realmObject, size_t* realmTables, size_t* innerViewsArg,
-      size_t* lazyArrayBuffersArg, size_t* objectMetadataTablesArg,
-      size_t* savedStacksSet, size_t* varNamesSet,
-      size_t* nonSyntacticLexicalEnvironmentsArg, size_t* jitRealm);
+  void addSizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf,
+                              size_t* tiAllocationSiteTables,
+                              size_t* tiArrayTypeTables,
+                              size_t* tiObjectTypeTables, size_t* realmObject,
+                              size_t* realmTables, size_t* innerViewsArg,
+                              size_t* objectMetadataTablesArg,
+                              size_t* savedStacksSet, size_t* varNamesSet,
+                              size_t* nonSyntacticLexicalEnvironmentsArg,
+                              size_t* jitRealm);
 
   JS::Zone* zone() { return zone_; }
   const JS::Zone* zone() const { return zone_; }

js/xpconnect/src/XPCJSRuntime.cpp

@@ -1895,10 +1895,6 @@ static void ReportRealmStats(const JS::RealmStats& realmStats,
                  realmStats.innerViewsTable,
                  "The table for array buffer inner views.");
 
-  ZRREPORT_BYTES(realmJSPathPrefix + NS_LITERAL_CSTRING("lazy-array-buffers"),
-                 realmStats.lazyArrayBuffersTable,
-                 "The table for typed object lazy array buffers.");
-
   ZRREPORT_BYTES(
       realmJSPathPrefix + NS_LITERAL_CSTRING("object-metadata"),
       realmStats.objectMetadataTable,