A64: Synchronize with r18642.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 1b91e689dd976440e17a6f3fc0b907e56981695b..d413950ca84aed4d1eb00dc76b28ce1be5cf3851 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -521,6 +521,7 @@ void Heap::ProcessPretenuringFeedback() {
 
     int i = 0;
     Object* list_element = allocation_sites_list();
+    bool trigger_deoptimization = false;
     while (use_scratchpad ?
               i < allocation_sites_scratchpad_length :
               list_element->IsAllocationSite()) {
@@ -530,12 +531,11 @@ void Heap::ProcessPretenuringFeedback() {
       if (site->memento_found_count() > 0) {
         active_allocation_sites++;
       }
-      if (site->DigestPretenuringFeedback()) {
-        if (site->GetPretenureMode() == TENURED) {
-          tenure_decisions++;
-        } else {
-          dont_tenure_decisions++;
-        }
+      if (site->DigestPretenuringFeedback()) trigger_deoptimization = true;
+      if (site->GetPretenureMode() == TENURED) {
+        tenure_decisions++;
+      } else {
+        dont_tenure_decisions++;
       }
       allocation_sites++;
       if (use_scratchpad) {
@@ -544,6 +544,9 @@ void Heap::ProcessPretenuringFeedback() {
         list_element = site->weak_next();
       }
     }
+
+    if (trigger_deoptimization) isolate_->stack_guard()->DeoptMarkedCode();
+
     allocation_sites_scratchpad_length = 0;
 
     // TODO(mvstanton): Pretenure decisions are only made once for an allocation
@@ -1983,14 +1986,22 @@ void Heap::ProcessAllocationSites(WeakObjectRetainer* retainer,
 
 
 void Heap::ResetAllAllocationSitesDependentCode(PretenureFlag flag) {
+  ASSERT(AllowCodeDependencyChange::IsAllowed());
+  DisallowHeapAllocation no_allocation_scope;
   Object* cur = allocation_sites_list();
+  bool marked = false;
   while (cur->IsAllocationSite()) {
     AllocationSite* casted = AllocationSite::cast(cur);
     if (casted->GetPretenureMode() == flag) {
       casted->ResetPretenureDecision();
+      bool got_marked = casted->dependent_code()->MarkCodeForDeoptimization(
+          isolate_,
+          DependentCode::kAllocationSiteTenuringChangedGroup);
+      if (got_marked) marked = true;
     }
     cur = casted->weak_next();
   }
+  if (marked) isolate_->stack_guard()->DeoptMarkedCode();
 }
 
 
@@ -3404,6 +3415,11 @@ bool Heap::CreateInitialObjects() {
   }
   set_natives_source_cache(FixedArray::cast(obj));
 
+  { MaybeObject* maybe_obj = AllocateCell(undefined_value());
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
+  set_undefined_cell(Cell::cast(obj));
+
   // Allocate object to hold object observation state.
   { MaybeObject* maybe_obj = AllocateMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
     if (!maybe_obj->ToObject(&obj)) return false;