[interpreter] Bytecode register optimizer.

src/interpreter/bytecodes.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_INTERPRETER_BYTECODES_H_
 #define V8_INTERPRETER_BYTECODES_H_
 
 #include <iosfwd>
 
 // Clients of this interface shouldn't depend on lots of interpreter internals.
@@ skipping 369 matching lines @@
   bool is_new_target() const;
 
   // Returns the register for the bytecode array.
   static Register bytecode_array();
   bool is_bytecode_array() const;
 
   // Returns the register for the saved bytecode offset.
   static Register bytecode_offset();
   bool is_bytecode_offset() const;
 
+  // Returns a register that can be used to represent the accumulator
+  // within code in the interpreter, but should never be emitted in
+  // bytecode.
+  static Register virtual_accumulator();
+
   OperandSize SizeOfOperand() const;
 
   int32_t ToOperand() const { return kRegisterFileStartOffset - index_; }
   static Register FromOperand(int32_t operand) {
     return Register(kRegisterFileStartOffset - operand);
   }
 
   static bool AreContiguous(Register reg1, Register reg2,
                             Register reg3 = Register(),
                             Register reg4 = Register(),
@@ skipping 98 matching lines @@
   static OperandType GetOperandType(Bytecode bytecode, int i);
 
   // Returns a pointer to an array of operand types terminated in
   // OperandType::kNone.
   static const OperandType* GetOperandTypes(Bytecode bytecode);
 
   // Returns the size of the i-th operand of |bytecode|.
   static OperandSize GetOperandSize(Bytecode bytecode, int i,
                                     OperandScale operand_scale);
 
+  // Returns a pointer to an array of the operand sizes for |bytecode|.
+  static const OperandSize* GetOperandSizes(Bytecode bytecode,
+                                            OperandScale operand_scale);
+
   // Returns the offset of the i-th operand of |bytecode| relative to the start
   // of the bytecode.
   static int GetOperandOffset(Bytecode bytecode, int i,
                               OperandScale operand_scale);
 
   // Returns a zero-based bitmap of the register operand positions of
   // |bytecode|.
   static int GetRegisterOperandBitmap(Bytecode bytecode);
 
   // Returns a debug break bytecode to replace |bytecode|.
@@ skipping 117 matching lines @@
   static OperandSize SizeForSignedOperand(int value);
 
   // Return the operand size required to hold an unsigned operand.
   static OperandSize SizeForUnsignedOperand(int value);
 
   // Return the operand size required to hold an unsigned operand.
   static OperandSize SizeForUnsignedOperand(size_t value);
 
   // Return the OperandScale required for bytecode emission of
   // operand sizes.
+  static OperandScale OperandSizesToScale(OperandSize size0);
+  static OperandScale OperandSizesToScale(OperandSize size0, OperandSize size1);
   static OperandScale OperandSizesToScale(
-      OperandSize size0, OperandSize size1 = OperandSize::kByte,
-      OperandSize size2 = OperandSize::kByte,
+      OperandSize size0, OperandSize size1, OperandSize size2,
       OperandSize size3 = OperandSize::kByte);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(Bytecodes);
 };
 
 class CreateObjectLiteralFlags {
  public:
   class FlagsBits : public BitField8<int, 0, 3> {};
   class FastClonePropertiesCountBits
       : public BitField8<int, FlagsBits::kNext, 3> {};
   STATIC_ASSERT((FlagsBits::kMask & FastClonePropertiesCountBits::kMask) == 0);
 };
 
 std::ostream& operator<<(std::ostream& os, const Bytecode& bytecode);
 std::ostream& operator<<(std::ostream& os, const AccumulatorUse& use);
 std::ostream& operator<<(std::ostream& os, const OperandScale& operand_scale);
 std::ostream& operator<<(std::ostream& os, const OperandSize& operand_size);
 std::ostream& operator<<(std::ostream& os, const OperandType& operand_type);
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODES_H_