bytecode-flags-and-tokens.h

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// Copyright 2016 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_BYTECODE_FLAGS_AND_TOKENS_H_
#define V8_INTERPRETER_BYTECODE_FLAGS_AND_TOKENS_H_
 
#include "src/base/bit-field.h"
#include "src/common/globals.h"
 
namespace v8 {
namespace internal {
 
// Forward declarations.
class Literal;
class AstStringConstants;
 
namespace interpreter {
 
class CreateArrayLiteralFlags {
 public:
  using FlagsBits = base::BitField8<int, 0, 5>;
  using FastCloneSupportedBit = FlagsBits::Next<bool, 1>;
 
  static uint8_t Encode(bool use_fast_shallow_clone, int runtime_flags);
 
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(CreateArrayLiteralFlags);
};
 
class CreateObjectLiteralFlags {
 public:
  using FlagsBits = base::BitField8<int, 0, 5>;
  using FastCloneSupportedBit = FlagsBits::Next<bool, 1>;
 
  static uint8_t Encode(int runtime_flags, bool fast_clone_supported);
 
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(CreateObjectLiteralFlags);
};
 
class CreateClosureFlags {
 public:
  using PretenuredBit = base::BitField8<bool, 0, 1>;
  using FastNewClosureBit = PretenuredBit::Next<bool, 1>;
 
  static uint8_t Encode(bool pretenure, bool is_function_scope,
                        bool might_always_turbofan);
 
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(CreateClosureFlags);
};
 
#define TYPEOF_LITERAL_LIST(V) \
  V(Number, number)            \
  V(String, string)            \
  V(Symbol, symbol)            \
  V(Boolean, boolean)          \
  V(BigInt, bigint)            \
  V(Undefined, undefined)      \
  V(Function, function)        \
  V(Object, object)            \
  V(Other, other)
 
class TestTypeOfFlags {
 public:
  enum class LiteralFlag : uint8_t {
#define DECLARE_LITERAL_FLAG(name, _) k##name,
    TYPEOF_LITERAL_LIST(DECLARE_LITERAL_FLAG)
#undef DECLARE_LITERAL_FLAG
  };
 
  static LiteralFlag GetFlagForLiteral(const AstStringConstants* ast_constants,
                                       Literal* literal);
  static uint8_t Encode(LiteralFlag literal_flag);
  static LiteralFlag Decode(uint8_t raw_flag);
 
  static const char* ToString(LiteralFlag literal_flag);
 
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(TestTypeOfFlags);
};
 
class StoreLookupSlotFlags {
 public:
  using LanguageModeBit = base::BitField8<LanguageMode, 0, 1>;
  using LookupHoistingModeBit = LanguageModeBit::Next<bool, 1>;
  static_assert(LanguageModeSize <= LanguageModeBit::kNumValues);
 
  static uint8_t Encode(LanguageMode language_mode,
                        LookupHoistingMode lookup_hoisting_mode);
 
  static LanguageMode GetLanguageMode(uint8_t flags);
  static bool IsLookupHoistingMode(uint8_t flags);
 
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(StoreLookupSlotFlags);
};
 
enum class TryFinallyContinuationToken: int {
  // Fixed value tokens for paths we know we need.
  // Fallthrough is set to -1 to make it the fallthrough case of the jump table,
  // where the remaining cases start at 0.
  kFallthroughToken = -1,
  // TODO(leszeks): Rethrow being 0 makes it use up a valuable LdaZero, which
  // means that other commands (such as break or return) have to use LdaSmi.
  // This can very slightly bloat bytecode, so perhaps token values should all
  // be shifted down by 1.
  kRethrowToken = 0
};
 
}  // namespace interpreter
}  // namespace internal
}  // namespace v8
 
#endif  // V8_INTERPRETER_BYTECODE_FLAGS_AND_TOKENS_H_