Re-land r8140: Deoptimize on never-executed code-paths.

src/hydrogen-instructions.h

 // Copyright 2011 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 128 matching lines @@
   V(OuterContext)                              \
   V(Parameter)                                 \
   V(Power)                                     \
   V(PushArgument)                              \
   V(RegExpLiteral)                             \
   V(Return)                                    \
   V(Sar)                                       \
   V(Shl)                                       \
   V(Shr)                                       \
   V(Simulate)                                  \
+  V(SoftDeoptimize)                            \
   V(StackCheck)                                \
   V(StoreContextSlot)                          \
   V(StoreGlobalCell)                           \
   V(StoreGlobalGeneric)                        \
   V(StoreKeyedFastElement)                     \
   V(StoreKeyedGeneric)                         \
   V(StoreKeyedSpecializedArrayElement)         \
   V(StoreNamedField)                           \
   V(StoreNamedGeneric)                         \
   V(StringAdd)                                 \
@@ skipping 681 matching lines @@
 class HBlockEntry: public HTemplateInstruction<0> {
  public:
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(BlockEntry)
 };
 
 
+// We insert soft-deoptimize when we hit code with unknown typefeedback,
+// so that we get a chance of re-optimizing with useful typefeedback.
+// HSoftDeoptimize does not end a basic block as opposed to HDeoptimize.
+class HSoftDeoptimize: public HTemplateInstruction<0> {
+ public:
+  virtual Representation RequiredInputRepresentation(int index) const {
+    return Representation::None();
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(SoftDeoptimize)
+};
+
+
 class HDeoptimize: public HControlInstruction {
  public:
   explicit HDeoptimize(int environment_length)
       : HControlInstruction(NULL, NULL),
         values_(environment_length) { }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::None();
   }
 
   virtual int OperandCount() { return values_.length(); }
   virtual HValue* OperandAt(int index) { return values_[index]; }
+  virtual void PrintDataTo(StringStream* stream);
 
   void AddEnvironmentValue(HValue* value) {
     values_.Add(NULL);
     SetOperandAt(values_.length() - 1, value);
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Deoptimize)
 
   enum UseEnvironment {
     kNoUses,
@@ skipping 3160 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_