Allocation site support for monomorphic StringAdds in BinaryOps.

src/ic.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 835 matching lines @@
         Isolate*, void (*Generate)(Isolate*, const State&));
 
     bool CanReuseDoubleBox() const {
       return (result_kind_ > SMI && result_kind_ <= NUMBER) &&
           ((mode_ == OVERWRITE_LEFT &&
             left_kind_ > SMI && left_kind_ <= NUMBER) ||
            (mode_ == OVERWRITE_RIGHT &&
             right_kind_ > SMI && right_kind_ <= NUMBER));
     }
 
+    // Returns true if the IC _could_ create allocation mementos.
+    bool CouldCreateAllocationMementos() const {
+      if (left_kind_ == STRING || right_kind_ == STRING) {
+        ASSERT_EQ(Token::ADD, op_);
+        return true;
+      }
+      return false;
+    }
+
+    // Returns true if the IC _should_ create allocation mementos.
+    bool ShouldCreateAllocationMementos() const {
+      return FLAG_allocation_site_pretenuring &&
+          CouldCreateAllocationMementos();
+    }
+
     bool HasSideEffects() const {
       return Max(left_kind_, right_kind_) == GENERIC;
     }
 
+    // Returns true if the IC should enable the inline smi code (i.e. if either
+    // parameter may be a smi).
     bool UseInlinedSmiCode() const {
       return KindMaybeSmi(left_kind_) || KindMaybeSmi(right_kind_);
     }
 
     static const int FIRST_TOKEN = Token::BIT_OR;
     static const int LAST_TOKEN = Token::MOD;
 
     Token::Value op() const { return op_; }
     OverwriteMode mode() const { return mode_; }
     Maybe<int> fixed_right_arg() const { return fixed_right_arg_; }
@@ skipping 41 matching lines @@
     Kind left_kind_;
     Kind right_kind_;
     Kind result_kind_;
     Maybe<int> fixed_right_arg_;
   };
 
   explicit BinaryOpIC(Isolate* isolate) : IC(EXTRA_CALL_FRAME, isolate) { }
 
   static Builtins::JavaScript TokenToJSBuiltin(Token::Value op);
 
-  MUST_USE_RESULT MaybeObject* Transition(Handle<Object> left,
-                                          Handle<Object> right);
+  MaybeObject* Transition(Handle<AllocationSite> allocation_site,
+                          Handle<Object> left,
+                          Handle<Object> right) V8_WARN_UNUSED_RESULT;
 };
 
 
 class CompareIC: public IC {
  public:
   // The type/state lattice is defined by the following inequations:
   //   UNINITIALIZED < ...
   //   ... < GENERIC
   //   SMI < NUMBER
   //   INTERNALIZED_STRING < STRING
@@ skipping 88 matching lines @@
 enum InlinedSmiCheck { ENABLE_INLINED_SMI_CHECK, DISABLE_INLINED_SMI_CHECK };
 void PatchInlinedSmiCode(Address address, InlinedSmiCheck check);
 
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, KeyedLoadIC_MissFromStubFailure);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, KeyedStoreIC_MissFromStubFailure);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, UnaryOpIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, StoreIC_MissFromStubFailure);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, KeyedCallIC_MissFromStubFailure);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, ElementsTransitionAndStoreIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, BinaryOpIC_Miss);
+DECLARE_RUNTIME_FUNCTION(MaybeObject*, BinaryOpIC_MissWithAllocationSite);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, CompareNilIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, ToBooleanIC_Miss);
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_H_