HSubAllocatedObject instruction allows hydrogen code to carve up

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index b60a23bc7e8de6ec84ae7ff514b64fa263bc1468..caaa611e7ec3c57273243d4ffe08da03ad3b4a32 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -171,6 +171,7 @@ class LChunkBuilder;
   V(StoreContextSlot)                          \
   V(StoreGlobalCell)                           \
   V(StoreGlobalGeneric)                        \
+  V(SubAllocatedObject)                        \

[Hannes Payer (out of office), 2013/03/13 08:48:39]

alphabetic order.

[mvstanton, 2013/03/13 10:14:40]

Done.

   V(StoreKeyed)                                \
   V(StoreKeyedGeneric)                         \
   V(StoreNamedField)                           \
@@ -4691,18 +4692,6 @@ inline bool StoringValueNeedsWriteBarrier(HValue* value) {
 }
 
 
-inline bool ReceiverObjectNeedsWriteBarrier(HValue* object,
-                                            HValue* new_space_dominator) {
-  if (object != new_space_dominator) return true;
-  if (object->IsFastLiteral()) return false;
-  if (object->IsAllocateObject()) return false;
-  if (object->IsAllocate()) {
-    return !HAllocate::cast(object)->GuaranteedInNewSpace();
-  }
-  return true;
-}
-
-
 class HStoreGlobalCell: public HUnaryOperation {
  public:
   HStoreGlobalCell(HValue* value,
@@ -5215,6 +5204,10 @@ class HLoadKeyedGeneric: public HTemplateInstruction<3> {
 };
 
 
+bool ReceiverObjectNeedsWriteBarrier(HValue* object,
+                                     HValue* new_space_dominator);
+

[Hannes Payer (out of office), 2013/03/13 08:48:39]

Can you move code around that you do not need this forward declaration? It would
be nice to keep ReceiverObjectNeedsWriteBarrier() where it was to have a clean
diff.

[mvstanton, 2013/03/13 10:14:40]

That is much better, thx...I was lazy :).

+
 class HStoreNamedField: public HTemplateInstruction<2> {
  public:
   HStoreNamedField(HValue* obj,
@@ -5311,6 +5304,47 @@ class HStoreNamedGeneric: public HTemplateInstruction<3> {
 };
 
 
+class HSubAllocatedObject: public HTemplateInstruction<1> {
+ public:
+  HSubAllocatedObject(HValue* value, int offset)
+      : offset_(offset) {
+    ASSERT(value->IsAllocate());
+    SetOperandAt(0, value);
+    set_representation(Representation::Tagged());
+  }
+
+  HValue* base_object() { return OperandAt(0); }
+  int offset() { return offset_; }
+
+  virtual Representation RequiredInputRepresentation(int index) {
+    return Representation::Tagged();
+  }
+
+  virtual void PrintDataTo(StringStream* stream);
+
+  DECLARE_CONCRETE_INSTRUCTION(SubAllocatedObject)

[Michael Starzinger, 2013/03/13 09:12:35]

Empty newline before the "private:" block.

[mvstanton, 2013/03/13 10:14:40]

Done.

+ private:
+  int offset_;
+};
+
+
+inline bool ReceiverObjectNeedsWriteBarrier(HValue* object,
+                                            HValue* new_space_dominator) {
+  if (object->IsSubAllocatedObject()) {
+    return ReceiverObjectNeedsWriteBarrier(
+        HSubAllocatedObject::cast(object)->base_object(),
+        new_space_dominator);
+  }
+  if (object != new_space_dominator) return true;
+  if (object->IsFastLiteral()) return false;
+  if (object->IsAllocateObject()) return false;
+  if (object->IsAllocate()) {
+    return !HAllocate::cast(object)->GuaranteedInNewSpace();
+  }
+  return true;
+}
+
+
 class HStoreKeyed
     : public HTemplateInstruction<3>, public ArrayInstructionInterface {
  public: