Added allocation folding support for old space allocations.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3186 matching lines @@
   ZoneList<HValue*> values_;
 };
 
 
 class HConstant: public HTemplateInstruction<0> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P1(HConstant, int32_t);
   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<Object>, 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();
       // Default arguments to is_not_in_new_space depend on this heap number
       // to be tenured so that it's guaranteed not be be located in new space.
       handle_ = factory->NewNumber(double_value_, TENURED);
     }
     AllowDeferredHandleDereference smi_check;
     ASSERT(has_int32_value_ || !handle_->IsSmi());
     return handle_;
@@ skipping 171 matching lines @@
   HConstant(int32_t value,
             Representation r = Representation::None(),
             bool is_not_in_new_space = true,
             Handle<Object> optional_handle = Handle<Object>::null());
   HConstant(double value,
             Representation r = Representation::None(),
             bool is_not_in_new_space = true,
             Handle<Object> optional_handle = Handle<Object>::null());
   HConstant(Handle<Object> handle,
             UniqueValueId unique_id,
-            Representation r,
-            HType type,
-            bool is_internalized_string,
-            bool is_not_in_new_space,
-            bool is_cell,
-            bool boolean_value);
+            Representation r = Representation::Tagged(),

[Michael Starzinger, 2013/08/09 09:22:58]

As discussed offline: Please don't add default parameters to this constructor.
This constructor should only be called for very well-known values, where all the
arguments can be explicitly specified.

[Hannes Payer (out of office), 2013/08/09 11:10:43]

Done.

+            HType type = HType::Tagged(),
+            bool is_internalized_string = false,
+            bool is_not_in_new_space = true,
+            bool is_cell = false,
+            bool boolean_value = false);
   explicit HConstant(ExternalReference reference);
 
   void Initialize(Representation r);
 
   virtual bool IsDeletable() const { return true; }
 
   // If this is a numerical constant, handle_ either points to to the
   // HeapObject the constant originated from or is null.  If the
   // constant is non-numeric, handle_ always points to a valid
   // constant HeapObject.
@@ skipping 1613 matching lines @@
   }
 
   void MakePrefillWithFiller() {
     flags_ = static_cast<HAllocate::Flags>(flags_ | PREFILL_WITH_FILLER);
   }
 
   void MakeDoubleAligned() {
     flags_ = static_cast<HAllocate::Flags>(flags_ | ALLOCATE_DOUBLE_ALIGNED);
   }
 
-  void UpdateSize(HValue* size) {
-    SetOperandAt(1, size);
-  }
-
   virtual void HandleSideEffectDominator(GVNFlag side_effect,
                                          HValue* dominator);
 
   virtual void PrintDataTo(StringStream* stream);
 
   DECLARE_CONCRETE_INSTRUCTION(Allocate)
 
  private:
   enum Flags {
     ALLOCATE_IN_NEW_SPACE = 1 << 0,
     ALLOCATE_IN_OLD_DATA_SPACE = 1 << 1,
     ALLOCATE_IN_OLD_POINTER_SPACE = 1 << 2,
     ALLOCATE_DOUBLE_ALIGNED = 1 << 3,
     PREFILL_WITH_FILLER = 1 << 4
   };
 
   HAllocate(HValue* context,
             HValue* size,
             HType type,
             PretenureFlag pretenure_flag,
             InstanceType instance_type)
-      : HTemplateInstruction<2>(type) {
+      : HTemplateInstruction<2>(type),
+        dominating_allocate_(NULL),
+        filler_free_space_size_(NULL) {
     SetOperandAt(0, context);
     SetOperandAt(1, size);
     set_representation(Representation::Tagged());
     SetFlag(kTrackSideEffectDominators);
     SetGVNFlag(kChangesNewSpacePromotion);
     SetGVNFlag(kDependsOnNewSpacePromotion);
     flags_ = pretenure_flag == TENURED
         ? (Heap::TargetSpaceId(instance_type) == OLD_POINTER_SPACE
             ? 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);
     }
   }
 
+  void UpdateSize(HValue* size) {
+    SetOperandAt(1, size);
+  }
+
+  HAllocate* GetFoldableDominator(HAllocate* dominator);
+
+  void UpdateFreeSpaceFiller(HConstant* old_filler_size, int32_t filler_size);
+
+  void CreateFreeSpaceFiller(HAllocate* dominator,
+                             int32_t dominator_size,
+                             int32_t filler_size);
+
+  bool IsFoldable(HAllocate* allocate) {
+    return (IsNewSpaceAllocation() && allocate->IsNewSpaceAllocation()) ||
+        (IsOldDataSpaceAllocation() && allocate->IsOldDataSpaceAllocation()) ||
+        (IsOldPointerSpaceAllocation() &&
+            allocate->IsOldPointerSpaceAllocation());
+  }
+
   Flags flags_;
   Handle<Map> known_initial_map_;
+  HAllocate* dominating_allocate_;
+  HConstant* filler_free_space_size_;
 };
 
 
 class HInnerAllocatedObject: public HTemplateInstruction<1> {
  public:
   static HInnerAllocatedObject* New(Zone* zone,
                                     HValue* context,
                                     HValue* value,
                                     int offset,
                                     HType type = HType::Tagged()) {
@@ skipping 1685 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_