src/x64/code-stubs-x64.h

// Copyright 2010 the V8 project authors. All rights reserved.
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// 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
//       with the distribution.
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#ifndef V8_X64_CODE_STUBS_X64_H_
#define V8_X64_CODE_STUBS_X64_H_

#include "ic-inl.h"
#include "type-info.h"

namespace v8 {
namespace internal {


// Compute a transcendental math function natively, or call the
// TranscendentalCache runtime function.
class TranscendentalCacheStub: public CodeStub {
 public:
  explicit TranscendentalCacheStub(TranscendentalCache::Type type)
      : type_(type) {}
  void Generate(MacroAssembler* masm);
 private:
  TranscendentalCache::Type type_;
  Major MajorKey() { return TranscendentalCache; }
  int MinorKey() { return type_; }
  Runtime::FunctionId RuntimeFunction();
  void GenerateOperation(MacroAssembler* masm, Label* on_nan_result);
};


class ToBooleanStub: public CodeStub {
 public:
  ToBooleanStub() { }

  void Generate(MacroAssembler* masm);

 private:
  Major MajorKey() { return ToBoolean; }
  int MinorKey() { return 0; }
};


// Flag that indicates how to generate code for the stub GenericBinaryOpStub.
enum GenericBinaryFlags {
  NO_GENERIC_BINARY_FLAGS = 0,
  NO_SMI_CODE_IN_STUB = 1 << 0  // Omit smi code in stub.
};


class GenericBinaryOpStub: public CodeStub {
 public:
  GenericBinaryOpStub(Token::Value op,
                      OverwriteMode mode,
                      GenericBinaryFlags flags,
                      TypeInfo operands_type = TypeInfo::Unknown())
      : op_(op),
        mode_(mode),
        flags_(flags),
        args_in_registers_(false),
        args_reversed_(false),
        static_operands_type_(operands_type),
        runtime_operands_type_(BinaryOpIC::DEFAULT),
        name_(NULL) {
    ASSERT(OpBits::is_valid(Token::NUM_TOKENS));
  }

  GenericBinaryOpStub(int key, BinaryOpIC::TypeInfo type_info)
      : op_(OpBits::decode(key)),
        mode_(ModeBits::decode(key)),
        flags_(FlagBits::decode(key)),
        args_in_registers_(ArgsInRegistersBits::decode(key)),
        args_reversed_(ArgsReversedBits::decode(key)),
        static_operands_type_(TypeInfo::ExpandedRepresentation(
            StaticTypeInfoBits::decode(key))),
        runtime_operands_type_(type_info),
        name_(NULL) {
  }

  // Generate code to call the stub with the supplied arguments. This will add
  // code at the call site to prepare arguments either in registers or on the
  // stack together with the actual call.
  void GenerateCall(MacroAssembler* masm, Register left, Register right);
  void GenerateCall(MacroAssembler* masm, Register left, Smi* right);
  void GenerateCall(MacroAssembler* masm, Smi* left, Register right);

  bool ArgsInRegistersSupported() {
    return (op_ == Token::ADD) || (op_ == Token::SUB)
        || (op_ == Token::MUL) || (op_ == Token::DIV);
  }

 private:
  Token::Value op_;
  OverwriteMode mode_;
  GenericBinaryFlags flags_;
  bool args_in_registers_;  // Arguments passed in registers not on the stack.
  bool args_reversed_;  // Left and right argument are swapped.

  // Number type information of operands, determined by code generator.
  TypeInfo static_operands_type_;

  // Operand type information determined at runtime.
  BinaryOpIC::TypeInfo runtime_operands_type_;

  char* name_;

  const char* GetName();

#ifdef DEBUG
  void Print() {
    PrintF("GenericBinaryOpStub %d (op %s), "
           "(mode %d, flags %d, registers %d, reversed %d, only_numbers %s)\n",
           MinorKey(),
           Token::String(op_),
           static_cast<int>(mode_),
           static_cast<int>(flags_),
           static_cast<int>(args_in_registers_),
           static_cast<int>(args_reversed_),
           static_operands_type_.ToString());
  }
#endif

  // Minor key encoding in 17 bits TTNNNFRAOOOOOOOMM.
  class ModeBits: public BitField<OverwriteMode, 0, 2> {};
  class OpBits: public BitField<Token::Value, 2, 7> {};
  class ArgsInRegistersBits: public BitField<bool, 9, 1> {};
  class ArgsReversedBits: public BitField<bool, 10, 1> {};
  class FlagBits: public BitField<GenericBinaryFlags, 11, 1> {};
  class StaticTypeInfoBits: public BitField<int, 12, 3> {};
  class RuntimeTypeInfoBits: public BitField<BinaryOpIC::TypeInfo, 15, 2> {};

  Major MajorKey() { return GenericBinaryOp; }
  int MinorKey() {
    // Encode the parameters in a unique 18 bit value.
    return OpBits::encode(op_)
           | ModeBits::encode(mode_)
           | FlagBits::encode(flags_)
           | ArgsInRegistersBits::encode(args_in_registers_)
           | ArgsReversedBits::encode(args_reversed_)
           | StaticTypeInfoBits::encode(
               static_operands_type_.ThreeBitRepresentation())
           | RuntimeTypeInfoBits::encode(runtime_operands_type_);
  }

  void Generate(MacroAssembler* masm);
  void GenerateSmiCode(MacroAssembler* masm, Label* slow);
  void GenerateLoadArguments(MacroAssembler* masm);
  void GenerateReturn(MacroAssembler* masm);
  void GenerateRegisterArgsPush(MacroAssembler* masm);
  void GenerateTypeTransition(MacroAssembler* masm);

  bool IsOperationCommutative() {
    return (op_ == Token::ADD) || (op_ == Token::MUL);
  }

  void SetArgsInRegisters() { args_in_registers_ = true; }
  void SetArgsReversed() { args_reversed_ = true; }
  bool HasSmiCodeInStub() { return (flags_ & NO_SMI_CODE_IN_STUB) == 0; }
  bool HasArgsInRegisters() { return args_in_registers_; }
  bool HasArgsReversed() { return args_reversed_; }

  bool ShouldGenerateSmiCode() {
    return HasSmiCodeInStub() &&
        runtime_operands_type_ != BinaryOpIC::HEAP_NUMBERS &&
        runtime_operands_type_ != BinaryOpIC::STRINGS;
  }

  bool ShouldGenerateFPCode() {
    return runtime_operands_type_ != BinaryOpIC::STRINGS;
  }

  virtual int GetCodeKind() { return Code::BINARY_OP_IC; }

  virtual InlineCacheState GetICState() {
    return BinaryOpIC::ToState(runtime_operands_type_);
  }

  friend class CodeGenerator;
};

class StringHelper : public AllStatic {
 public:
  // Generate code for copying characters using a simple loop. This should only
  // be used in places where the number of characters is small and the
  // additional setup and checking in GenerateCopyCharactersREP adds too much
  // overhead. Copying of overlapping regions is not supported.
  static void GenerateCopyCharacters(MacroAssembler* masm,
                                     Register dest,
                                     Register src,
                                     Register count,
                                     bool ascii);

  // Generate code for copying characters using the rep movs instruction.
  // Copies rcx characters from rsi to rdi. Copying of overlapping regions is
  // not supported.
  static void GenerateCopyCharactersREP(MacroAssembler* masm,
                                        Register dest,     // Must be rdi.
                                        Register src,      // Must be rsi.
                                        Register count,    // Must be rcx.
                                        bool ascii);


  // Probe the symbol table for a two character string. If the string is
  // not found by probing a jump to the label not_found is performed. This jump
  // does not guarantee that the string is not in the symbol table. If the
  // string is found the code falls through with the string in register rax.
  static void GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
                                                   Register c1,
                                                   Register c2,
                                                   Register scratch1,
                                                   Register scratch2,
                                                   Register scratch3,
                                                   Register scratch4,
                                                   Label* not_found);

  // Generate string hash.
  static void GenerateHashInit(MacroAssembler* masm,
                               Register hash,
                               Register character,
                               Register scratch);
  static void GenerateHashAddCharacter(MacroAssembler* masm,
                                       Register hash,
                                       Register character,
                                       Register scratch);
  static void GenerateHashGetHash(MacroAssembler* masm,
                                  Register hash,
                                  Register scratch);

 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
};


// Flag that indicates how to generate code for the stub StringAddStub.
enum StringAddFlags {
  NO_STRING_ADD_FLAGS = 0,
  NO_STRING_CHECK_IN_STUB = 1 << 0  // Omit string check in stub.
};


class StringAddStub: public CodeStub {
 public:
  explicit StringAddStub(StringAddFlags flags) {
    string_check_ = ((flags & NO_STRING_CHECK_IN_STUB) == 0);
  }

 private:
  Major MajorKey() { return StringAdd; }
  int MinorKey() { return string_check_ ? 0 : 1; }

  void Generate(MacroAssembler* masm);

  // Should the stub check whether arguments are strings?
  bool string_check_;
};


class SubStringStub: public CodeStub {
 public:
  SubStringStub() {}

 private:
  Major MajorKey() { return SubString; }
  int MinorKey() { return 0; }

  void Generate(MacroAssembler* masm);
};


class StringCompareStub: public CodeStub {
 public:
  explicit StringCompareStub() {}

  // Compare two flat ascii strings and returns result in rax after popping two
  // arguments from the stack.
  static void GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
                                              Register left,
                                              Register right,
                                              Register scratch1,
                                              Register scratch2,
                                              Register scratch3,
                                              Register scratch4);

 private:
  Major MajorKey() { return StringCompare; }
  int MinorKey() { return 0; }

  void Generate(MacroAssembler* masm);
};


class NumberToStringStub: public CodeStub {
 public:
  NumberToStringStub() { }

  // Generate code to do a lookup in the number string cache. If the number in
  // the register object is found in the cache the generated code falls through
  // with the result in the result register. The object and the result register
  // can be the same. If the number is not found in the cache the code jumps to
  // the label not_found with only the content of register object unchanged.
  static void GenerateLookupNumberStringCache(MacroAssembler* masm,
                                              Register object,
                                              Register result,
                                              Register scratch1,
                                              Register scratch2,
                                              bool object_is_smi,
                                              Label* not_found);

 private:
  static void GenerateConvertHashCodeToIndex(MacroAssembler* masm,
                                             Register hash,
                                             Register mask);

  Major MajorKey() { return NumberToString; }
  int MinorKey() { return 0; }

  void Generate(MacroAssembler* masm);

  const char* GetName() { return "NumberToStringStub"; }

#ifdef DEBUG
  void Print() {
    PrintF("NumberToStringStub\n");
  }
#endif
};


class RecordWriteStub : public CodeStub {
 public:
  RecordWriteStub(Register object, Register addr, Register scratch)
      : object_(object), addr_(addr), scratch_(scratch) { }

  void Generate(MacroAssembler* masm);

 private:
  Register object_;
  Register addr_;
  Register scratch_;

#ifdef DEBUG
  void Print() {
    PrintF("RecordWriteStub (object reg %d), (addr reg %d), (scratch reg %d)\n",
           object_.code(), addr_.code(), scratch_.code());
  }
#endif

  // Minor key encoding in 12 bits. 4 bits for each of the three
  // registers (object, address and scratch) OOOOAAAASSSS.
  class ScratchBits : public BitField<uint32_t, 0, 4> {};
  class AddressBits : public BitField<uint32_t, 4, 4> {};
  class ObjectBits : public BitField<uint32_t, 8, 4> {};

  Major MajorKey() { return RecordWrite; }

  int MinorKey() {
    // Encode the registers.
    return ObjectBits::encode(object_.code()) |
           AddressBits::encode(addr_.code()) |
           ScratchBits::encode(scratch_.code());
  }
};


} }  // namespace v8::internal

#endif  // V8_X64_CODE_STUBS_X64_H_