HStoreNamedField for Smis optimized for x64

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 6514 matching lines @@
     if (index == 0 && access().IsExternalMemory()) {
       // object must be external in case of external memory access
       return Representation::External();
     } else if (index == 1) {
       if (field_representation().IsInteger8() ||
           field_representation().IsUInteger8() ||
           field_representation().IsInteger16() ||
           field_representation().IsUInteger16() ||
           field_representation().IsInteger32()) {
         return Representation::Integer32();
-      } else if (field_representation().IsDouble() ||
-                 field_representation().IsSmi()) {
+      } else if (field_representation().IsDouble()) {
+        return field_representation();
+      } else if (field_representation().IsSmi()) {
+        if (SmiValuesAre32Bits()) {
+          return Representation::Integer32();
+        }
         return field_representation();
       } else if (field_representation().IsExternal()) {
         return Representation::External();
       }
     }
     return Representation::Tagged();
   }
   virtual void HandleSideEffectDominator(GVNFlag side_effect,
                                          HValue* dominator) V8_OVERRIDE {
     ASSERT(side_effect == kChangesNewSpacePromotion);
     new_space_dominator_ = dominator;
   }
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   void SkipWriteBarrier() { write_barrier_mode_ = SKIP_WRITE_BARRIER; }
   bool IsSkipWriteBarrier() const {
     return write_barrier_mode_ == SKIP_WRITE_BARRIER;
   }
 
   HValue* object() const { return OperandAt(0); }
   HValue* value() const { return OperandAt(1); }
   HValue* transition() const { return OperandAt(2); }
 
   HObjectAccess access() const { return access_; }
   HValue* new_space_dominator() const { return new_space_dominator_; }
   bool has_transition() const { return has_transition_; }
 
+  // Controls whether it is guaranteed that the smi word already contains
+  // correct smi tag (currently applicable only for x64).
+  bool can_omit_smi_tag_store() const { return can_omit_smi_tag_store_; }
+  void set_can_omit_smi_tag_store(bool v) { can_omit_smi_tag_store_ = v; }

[Toon Verwaest, 2013/12/09 15:51:10]

I'd rather distinguish between "initializing stores" and stores to existing
fields.

// Indicates whether this is a store to a field that was previously initialized
to a value of the same representation.
bool store_to_initialized_field();

[Igor Sheludko, 2013/12/10 09:13:08]

Good suggestion! Done.

+
   Handle<Map> transition_map() const {
     if (has_transition()) {
       return Handle<Map>::cast(
           HConstant::cast(transition())->handle(Isolate::Current()));
     } else {
       return Handle<Map>();
     }
   }
 
   void SetTransition(HConstant* map_constant, CompilationInfo* info) {
@@ skipping 33 matching lines @@
     SetOperandAt(1, value);
   }
 
  private:
   HStoreNamedField(HValue* obj,
                    HObjectAccess access,
                    HValue* val)
       : access_(access),
         new_space_dominator_(NULL),
         write_barrier_mode_(UPDATE_WRITE_BARRIER),
-        has_transition_(false) {
+        has_transition_(false),
+        can_omit_smi_tag_store_(false) {
     SetOperandAt(0, obj);
     SetOperandAt(1, val);
     SetOperandAt(2, obj);
     access.SetGVNFlags(this, true);
   }
 
   HObjectAccess access_;
   HValue* new_space_dominator_;
   WriteBarrierMode write_barrier_mode_ : 1;
   bool has_transition_ : 1;
+  bool can_omit_smi_tag_store_ : 1;
 };
 
 
 class HStoreNamedGeneric V8_FINAL : public HTemplateInstruction<3> {
  public:
   DECLARE_INSTRUCTION_WITH_CONTEXT_FACTORY_P4(HStoreNamedGeneric, HValue*,
                                               Handle<String>, HValue*,
                                               StrictModeFlag);
   HValue* object() { return OperandAt(0); }
   HValue* value() { return OperandAt(1); }
@@ skipping 851 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_