A64: Synchronize with r19234.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 1bcd5d09f628a84be179b1dddc8a62be00c53e4a..0e3750664eaa7941824c14b645a7f5a001bc4d71 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -150,7 +150,7 @@ Heap::Heap()
 #ifdef VERIFY_HEAP
       no_weak_object_verification_scope_depth_(0),
 #endif
-      allocation_sites_scratchpad_length(0),
+      allocation_sites_scratchpad_length_(0),
       promotion_queue_(this),
       configured_(false),
       external_string_table_(this),
@@ -516,16 +516,17 @@ void Heap::ProcessPretenuringFeedback() {
     // If the scratchpad overflowed, we have to iterate over the allocation
     // sites list.
     bool use_scratchpad =
-        allocation_sites_scratchpad_length < kAllocationSiteScratchpadSize;
+        allocation_sites_scratchpad_length_ < kAllocationSiteScratchpadSize;
 
     int i = 0;
     Object* list_element = allocation_sites_list();
     bool trigger_deoptimization = false;
     while (use_scratchpad ?
-              i < allocation_sites_scratchpad_length :
+              i < allocation_sites_scratchpad_length_ :
               list_element->IsAllocationSite()) {
       AllocationSite* site = use_scratchpad ?
-        allocation_sites_scratchpad[i] : AllocationSite::cast(list_element);
+          AllocationSite::cast(allocation_sites_scratchpad()->get(i)) :
+          AllocationSite::cast(list_element);
       allocation_mementos_found += site->memento_found_count();
       if (site->memento_found_count() > 0) {
         active_allocation_sites++;
@@ -546,12 +547,9 @@ void Heap::ProcessPretenuringFeedback() {
 
     if (trigger_deoptimization) isolate_->stack_guard()->DeoptMarkedCode();
 
-    allocation_sites_scratchpad_length = 0;
+    FlushAllocationSitesScratchpad();
 
-    // TODO(mvstanton): Pretenure decisions are only made once for an allocation
-    // site. Find a sane way to decide about revisiting the decision later.
-
-    if (FLAG_trace_track_allocation_sites &&
+    if (FLAG_trace_pretenuring_statistics &&
         (allocation_mementos_found > 0 ||
          tenure_decisions > 0 ||
          dont_tenure_decisions > 0)) {
@@ -739,7 +737,7 @@ void Heap::CollectAllAvailableGarbage(const char* gc_reason) {
   const int kMaxNumberOfAttempts = 7;
   const int kMinNumberOfAttempts = 2;
   for (int attempt = 0; attempt < kMaxNumberOfAttempts; attempt++) {
-    if (!CollectGarbage(OLD_POINTER_SPACE, MARK_COMPACTOR, gc_reason, NULL) &&
+    if (!CollectGarbage(MARK_COMPACTOR, gc_reason, NULL) &&
         attempt + 1 >= kMinNumberOfAttempts) {
       break;
     }
@@ -751,8 +749,7 @@ void Heap::CollectAllAvailableGarbage(const char* gc_reason) {
 }
 
 
-bool Heap::CollectGarbage(AllocationSpace space,
-                          GarbageCollector collector,
+bool Heap::CollectGarbage(GarbageCollector collector,
                           const char* gc_reason,
                           const char* collector_reason,
                           const v8::GCCallbackFlags gc_callback_flags) {
@@ -768,6 +765,18 @@ bool Heap::CollectGarbage(AllocationSpace space,
   allocation_timeout_ = Max(6, FLAG_gc_interval);
 #endif
 
+  // There may be an allocation memento behind every object in new space.
+  // If we evacuate a not full new space or if we are on the last page of
+  // the new space, then there may be uninitialized memory behind the top
+  // pointer of the new space page. We store a filler object there to
+  // identify the unused space.
+  Address from_top = new_space_.top();
+  Address from_limit = new_space_.limit();
+  if (from_top < from_limit) {
+    int remaining_in_page = static_cast<int>(from_limit - from_top);
+    CreateFillerObjectAt(from_top, remaining_in_page);
+  }
+
   if (collector == SCAVENGER && !incremental_marking()->IsStopped()) {
     if (FLAG_trace_incremental_marking) {
       PrintF("[IncrementalMarking] Scavenge during marking.\n");
@@ -3297,6 +3306,12 @@ bool Heap::CreateInitialObjects() {
   // Handling of script id generation is in Factory::NewScript.
   set_last_script_id(Smi::FromInt(v8::Script::kNoScriptId));
 
+  { MaybeObject* maybe_obj = AllocateAllocationSitesScratchpad();
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
+  set_allocation_sites_scratchpad(FixedArray::cast(obj));
+  InitializeAllocationSitesScratchpad();
+
   // Initialize keyed lookup cache.
   isolate_->keyed_lookup_cache()->Clear();
 
@@ -3586,6 +3601,39 @@ MaybeObject* Heap::Uint32ToString(uint32_t value,
 }
 
 
+MaybeObject* Heap::AllocateAllocationSitesScratchpad() {
+  MaybeObject* maybe_obj =
+      AllocateFixedArray(kAllocationSiteScratchpadSize, TENURED);
+  return maybe_obj;
+}
+
+
+void Heap::FlushAllocationSitesScratchpad() {
+  for (int i = 0; i < allocation_sites_scratchpad_length_; i++) {
+    allocation_sites_scratchpad()->set_undefined(i);
+  }
+  allocation_sites_scratchpad_length_ = 0;
+}
+
+
+void Heap::InitializeAllocationSitesScratchpad() {
+  ASSERT(allocation_sites_scratchpad()->length() ==
+         kAllocationSiteScratchpadSize);
+  for (int i = 0; i < kAllocationSiteScratchpadSize; i++) {
+    allocation_sites_scratchpad()->set_undefined(i);
+  }
+}
+
+
+void Heap::AddAllocationSiteToScratchpad(AllocationSite* site) {
+  if (allocation_sites_scratchpad_length_ < kAllocationSiteScratchpadSize) {
+    allocation_sites_scratchpad()->set(
+        allocation_sites_scratchpad_length_, site);
+    allocation_sites_scratchpad_length_++;
+  }
+}
+
+
 Map* Heap::MapForExternalArrayType(ExternalArrayType array_type) {
   return Map::cast(roots_[RootIndexForExternalArrayType(array_type)]);
 }