Merged r16393 into 3.20 branch.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 72b02a68950923cb6be491bcb9c0d5df1fe493c9..f2ea7b0cf4b409ab41f453f87420a2491f0c6bed 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -49,11 +49,11 @@ class HEnvironment;
 class HInferRepresentationPhase;
 class HInstruction;
 class HLoopInformation;
+class HStoreNamedField;
 class HValue;
 class LInstruction;
 class LChunkBuilder;
 
-
 #define HYDROGEN_ABSTRACT_INSTRUCTION_LIST(V)  \
   V(ArithmeticBinaryOperation)                 \
   V(BinaryOperation)                           \
@@ -3204,8 +3204,27 @@ class HConstant: public HTemplateInstruction<0> {
   DECLARE_INSTRUCTION_FACTORY_P2(HConstant, int32_t, Representation);
   DECLARE_INSTRUCTION_FACTORY_P1(HConstant, double);
   DECLARE_INSTRUCTION_FACTORY_P1(HConstant, Handle<Object>);
+  DECLARE_INSTRUCTION_FACTORY_P2(HConstant, Handle<Map>, UniqueValueId);
   DECLARE_INSTRUCTION_FACTORY_P1(HConstant, ExternalReference);
 
+  static HConstant* CreateAndInsertAfter(Zone* zone,
+                                         HValue* context,
+                                         int32_t value,
+                                         HInstruction* instruction) {
+    HConstant* new_constant = HConstant::New(zone, context, value);
+    new_constant->InsertAfter(instruction);
+    return new_constant;
+  }
+
+  static HConstant* CreateAndInsertBefore(Zone* zone,
+                                          HValue* context,
+                                          int32_t value,
+                                          HInstruction* instruction) {
+    HConstant* new_constant = HConstant::New(zone, context, value);
+    new_constant->InsertBefore(instruction);
+    return new_constant;
+  }
+
   Handle<Object> handle() {
     if (handle_.is_null()) {
       Factory* factory = Isolate::Current()->factory();
@@ -3408,6 +3427,8 @@ class HConstant: public HTemplateInstruction<0> {
             bool is_not_in_new_space,
             bool is_cell,
             bool boolean_value);
+  HConstant(Handle<Map> handle,
+            UniqueValueId unique_id);
   explicit HConstant(ExternalReference reference);
 
   void Initialize(Representation r);
@@ -5098,7 +5119,10 @@ class HAllocate: public HTemplateInstruction<2> {
             HType type,
             PretenureFlag pretenure_flag,
             InstanceType instance_type)
-      : HTemplateInstruction<2>(type) {
+      : HTemplateInstruction<2>(type),
+        dominating_allocate_(NULL),
+        filler_free_space_size_(NULL),
+        clear_next_map_word_(false) {
     SetOperandAt(0, context);
     SetOperandAt(1, size);
     set_representation(Representation::Tagged());
@@ -5110,13 +5134,40 @@ class HAllocate: public HTemplateInstruction<2> {
             ? ALLOCATE_IN_OLD_POINTER_SPACE : ALLOCATE_IN_OLD_DATA_SPACE)
         : ALLOCATE_IN_NEW_SPACE;
     if (instance_type == FIXED_DOUBLE_ARRAY_TYPE) {
-      flags_ = static_cast<HAllocate::Flags>(flags_ |
-          ALLOCATE_DOUBLE_ALIGNED);
+      flags_ = static_cast<HAllocate::Flags>(flags_ | ALLOCATE_DOUBLE_ALIGNED);
     }
+    // We have to fill the allocated object with one word fillers if we do
+    // not use allocation folding since some allocations may depend on each
+    // other, i.e., have a pointer to each other. A GC in between these
+    // allocations may leave such objects behind in a not completely initialized
+    // state.
+    if (!FLAG_use_gvn || !FLAG_use_allocation_folding) {
+      flags_ = static_cast<HAllocate::Flags>(flags_ | PREFILL_WITH_FILLER);
+    }
+    clear_next_map_word_ = pretenure_flag == NOT_TENURED &&
+        AllocationSite::CanTrack(instance_type);
+  }
+
+  HAllocate* GetFoldableDominator(HAllocate* dominator);
+
+  void UpdateFreeSpaceFiller(int32_t filler_size);
+
+  void CreateFreeSpaceFiller(int32_t filler_size);
+
+  bool IsFoldable(HAllocate* allocate) {
+    return (IsNewSpaceAllocation() && allocate->IsNewSpaceAllocation()) ||
+        (IsOldDataSpaceAllocation() && allocate->IsOldDataSpaceAllocation()) ||
+        (IsOldPointerSpaceAllocation() &&
+            allocate->IsOldPointerSpaceAllocation());
   }
 
+  void ClearNextMapWord(int offset);
+
   Flags flags_;
   Handle<Map> known_initial_map_;
+  HAllocate* dominating_allocate_;
+  HStoreNamedField* filler_free_space_size_;
+  bool clear_next_map_word_;
 };
 
 
@@ -5973,6 +6024,10 @@ class HStoreNamedField: public HTemplateInstruction<3> {
     return access_.representation();
   }
 
+  void UpdateValue(HValue* value) {
+    SetOperandAt(1, value);
+  }
+
  private:
   HStoreNamedField(HValue* obj,
                    HObjectAccess access,