Revert "Revert "Revert "Revert "[global-handles] Remove dead code""""

This reverts commit 682d5369.

Reason for revert: Didn't see that this was the Reland... now we should be in good state.

Original change's description:
> Revert "Revert "Revert "[global-handles] Remove dead code"""
> 
> This reverts commit c836a95e.
> 
> Reason for revert: I don't think this was related.
> 
> Original change's description:
> > Revert "Revert "[global-handles] Remove dead code""
> > 
> > This reverts commit 58020872.
> > 
> > Reason for revert: Turned out to be a bot issue, reverting the revert. 
> > 
> > Original change's description:
> > > Revert "[global-handles] Remove dead code"
> > > 
> > > This reverts commit e2890c19.
> > > 
> > > Reason for revert: Looks like this CL causes slowdown on multiple builders, Check tests timeout and raise exceptions on the bot. Possible it is a bot issue as well, see tracking bug - https://bugs.chromium.org/p/chromium/issues/detail?id=720606
> > > 
> > > Original change's description:
> > > > [global-handles] Remove dead code
> > > > 
> > > > Bug: chromium:720477
> > > > Change-Id: I090168c575c41b7038af5dfba6cd8973d1154c51
> > > > Reviewed-on: https://chromium-review.googlesource.com/501790
> > > > Reviewed-by: Hannes Payer <hpayer@chromium.org>
> > > > Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> > > > Cr-Commit-Position: refs/heads/master@{#45241}
> > > 
> > > TBR=hpayer@chromium.org,mlippautz@chromium.org,jochen@chromium.org
> > > NOPRESUBMIT=true
> > > NOTREECHECKS=true
> > > NOTRY=true
> > > Bug: chromium:720477
> > > 
> > > Change-Id: I92f40d8c4dbfdb5208b3068648612e8c5b97fb20
> > > Reviewed-on: https://chromium-review.googlesource.com/502029
> > > Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
> > > Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#45243}
> > 
> > TBR=hpayer@chromium.org,gdeepti@chromium.org,mlippautz@chromium.org,jochen@chromium.org,v8-reviews@googlegroups.com
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > Bug: chromium:720477
> > 
> > Change-Id: I70e190e0c27074228a8128aa849e5a419af915e8
> > Reviewed-on: https://chromium-review.googlesource.com/502030
> > Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
> > Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#45244}
> 
> TBR=hpayer@chromium.org,gdeepti@chromium.org,mlippautz@chromium.org,jochen@chromium.org,v8-reviews@googlegroups.com
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> Bug: chromium:720477
> 
> Change-Id: If3e4abea51d87546e25076b906a4c91e5ccf947b
> Reviewed-on: https://chromium-review.googlesource.com/503007
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#45246}

TBR=hpayer@chromium.org,gdeepti@chromium.org,mlippautz@chromium.org,jochen@chromium.org,v8-reviews@googlegroups.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Bug: chromium:720477

Change-Id: Id7dc886cc20b3b36ca5bb643686fe4fe2e98a3a7
Reviewed-on: https://chromium-review.googlesource.com/503008Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45261}

src/global-handles.cc

@@ -647,19 +647,6 @@ void GlobalHandles::IterateNewSpaceStrongAndDependentRoots(RootVisitor* v) {
   }
 }
 
-
-void GlobalHandles::IdentifyNewSpaceWeakIndependentHandles(
-    WeakSlotCallbackWithHeap f) {
-  for (int i = 0; i < new_space_nodes_.length(); ++i) {
-    Node* node = new_space_nodes_[i];
-    DCHECK(node->is_in_new_space_list());
-    if (node->is_independent() && node->IsWeak() &&
-        f(isolate_->heap(), node->location())) {
-      node->MarkPending();
-    }
-  }
-}
-
 void GlobalHandles::IterateNewSpaceWeakIndependentRoots(RootVisitor* v) {
   for (int i = 0; i < new_space_nodes_.length(); ++i) {
     Node* node = new_space_nodes_[i];
@@ -703,7 +690,6 @@ void GlobalHandles::MarkNewSpaceWeakUnmodifiedObjectsPending(
   }
 }
 
-template <GlobalHandles::IterationMode mode>
 void GlobalHandles::IterateNewSpaceWeakUnmodifiedRoots(RootVisitor* v) {
   for (int i = 0; i < new_space_nodes_.length(); ++i) {
     Node* node = new_space_nodes_[i];
@@ -712,36 +698,18 @@ void GlobalHandles::IterateNewSpaceWeakUnmodifiedRoots(RootVisitor* v) {
         node->IsWeakRetainer()) {
       // Pending weak phantom handles die immediately. Everything else survives.
       if (node->IsPendingPhantomResetHandle()) {
-        if (mode == IterationMode::HANDLE_PHANTOM_NODES ||
-            mode == IterationMode::HANDLE_PHANTOM_NODES_VISIT_OTHERS) {
-          node->ResetPhantomHandle();
-          ++number_of_phantom_handle_resets_;
-        }
+        node->ResetPhantomHandle();
+        ++number_of_phantom_handle_resets_;
       } else if (node->IsPendingPhantomCallback()) {
-        if (mode == IterationMode::HANDLE_PHANTOM_NODES ||
-            mode == IterationMode::HANDLE_PHANTOM_NODES_VISIT_OTHERS) {
-          node->CollectPhantomCallbackData(isolate(),
-                                           &pending_phantom_callbacks_);
-        }
+        node->CollectPhantomCallbackData(isolate(),
+                                         &pending_phantom_callbacks_);
       } else {
-        if (mode == IterationMode::VISIT_OTHERS ||
-            mode == IterationMode::HANDLE_PHANTOM_NODES_VISIT_OTHERS) {
-          v->VisitRootPointer(Root::kGlobalHandles, node->location());
-        }
+        v->VisitRootPointer(Root::kGlobalHandles, node->location());
       }
     }
   }
 }
 
-template void GlobalHandles::IterateNewSpaceWeakUnmodifiedRoots<
-    GlobalHandles::HANDLE_PHANTOM_NODES>(RootVisitor* v);
-
-template void GlobalHandles::IterateNewSpaceWeakUnmodifiedRoots<
-    GlobalHandles::VISIT_OTHERS>(RootVisitor* v);
-
-template void GlobalHandles::IterateNewSpaceWeakUnmodifiedRoots<
-    GlobalHandles::HANDLE_PHANTOM_NODES_VISIT_OTHERS>(RootVisitor* v);
-
 void GlobalHandles::InvokeSecondPassPhantomCallbacks(
     List<PendingPhantomCallback>* callbacks, Isolate* isolate) {
   while (callbacks->length() != 0) {
@@ -998,30 +966,6 @@ void GlobalHandles::IterateWeakRootsInNewSpaceWithClassIds(
   }
 }
 
-
-int GlobalHandles::NumberOfWeakHandles() {
-  int count = 0;
-  for (NodeIterator it(this); !it.done(); it.Advance()) {
-    if (it.node()->IsWeakRetainer()) {
-      count++;
-    }
-  }
-  return count;
-}
-
-
-int GlobalHandles::NumberOfGlobalObjectWeakHandles() {
-  int count = 0;
-  for (NodeIterator it(this); !it.done(); it.Advance()) {
-    if (it.node()->IsWeakRetainer() &&
-        it.node()->object()->IsJSGlobalObject()) {
-      count++;
-    }
-  }
-  return count;
-}
-
-
 void GlobalHandles::RecordStats(HeapStats* stats) {
   *stats->global_handle_count = 0;
   *stats->weak_global_handle_count = 0;
@@ -1081,9 +1025,7 @@ void GlobalHandles::Print() {
 
 #endif
 
-void GlobalHandles::TearDown() {
-  // TODO(1428): invoke weak callbacks.
-}
+void GlobalHandles::TearDown() {}
 
 EternalHandles::EternalHandles() : size_(0) {
   for (unsigned i = 0; i < arraysize(singleton_handles_); i++) {

src/global-handles.h

@@ -43,12 +43,6 @@ enum WeaknessType {
 
 class GlobalHandles {
  public:
-  enum IterationMode {
-    HANDLE_PHANTOM_NODES_VISIT_OTHERS,
-    VISIT_OTHERS,
-    HANDLE_PHANTOM_NODES
-  };
-
   ~GlobalHandles();
 
   // Creates a new global handle that is alive until Destroy is called.
@@ -85,13 +79,6 @@ class GlobalHandles {
 
   void RecordStats(HeapStats* stats);
 
-  // Returns the current number of weak handles.
-  int NumberOfWeakHandles();
-
-  // Returns the current number of weak handles to global objects.
-  // These handles are also included in NumberOfWeakHandles().
-  int NumberOfGlobalObjectWeakHandles();
-
   // Returns the current number of handles to global objects.
   int global_handles_count() const {
     return number_of_global_handles_;
@@ -158,10 +145,6 @@ class GlobalHandles {
   // Iterates over strong and dependent handles. See the node above.
   void IterateNewSpaceStrongAndDependentRoots(RootVisitor* v);
 
-  // Finds weak independent or partially independent handles satisfying
-  // the callback predicate and marks them as pending. See the note above.
-  void IdentifyNewSpaceWeakIndependentHandles(WeakSlotCallbackWithHeap f);
-
   // Iterates over weak independent or partially independent handles.
   // See the note above.
   void IterateNewSpaceWeakIndependentRoots(RootVisitor* v);
@@ -173,7 +156,6 @@ class GlobalHandles {
 
   // Iterates over weak independent or unmodified handles.
   // See the note above.
-  template <IterationMode mode>
   void IterateNewSpaceWeakUnmodifiedRoots(RootVisitor* v);
 
   // Identify unmodified objects that are in weak state and marks them

src/heap/heap.cc

@@ -1781,11 +1781,8 @@ void Heap::Scavenge() {
   isolate()->global_handles()->MarkNewSpaceWeakUnmodifiedObjectsPending(
       &IsUnscavengedHeapObject);
 
-  isolate()
-      ->global_handles()
-      ->IterateNewSpaceWeakUnmodifiedRoots<
-          GlobalHandles::HANDLE_PHANTOM_NODES_VISIT_OTHERS>(
-          &root_scavenge_visitor);
+  isolate()->global_handles()->IterateNewSpaceWeakUnmodifiedRoots(
+      &root_scavenge_visitor);
   new_space_front = DoScavenge(new_space_front);
 
   UpdateNewSpaceReferencesInExternalStringTable(

src/heap/mark-compact.cc

@@ -2617,10 +2617,8 @@ void MinorMarkCompactCollector::MarkLiveObjects() {
     TRACE_GC(heap()->tracer(), GCTracer::Scope::MINOR_MC_MARK_GLOBAL_HANDLES);
     isolate()->global_handles()->MarkNewSpaceWeakUnmodifiedObjectsPending(
         &IsUnmarkedObjectForYoungGeneration);
-    isolate()
-        ->global_handles()
-        ->IterateNewSpaceWeakUnmodifiedRoots<
-            GlobalHandles::HANDLE_PHANTOM_NODES_VISIT_OTHERS>(&root_visitor);
+    isolate()->global_handles()->IterateNewSpaceWeakUnmodifiedRoots(
+        &root_visitor);
     ProcessMarkingDeque();
   }