text: // Copyright 2013 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_COMPILER_MACHINE_OPERATOR_H_
  #define V8_COMPILER_MACHINE_OPERATOR_H_
  
  #include "src/base/flags.h"
  #include "src/compiler/machine-type.h"
  
  namespace v8 {
  namespace internal {
  namespace compiler {
  
  // Forward declarations.
  struct MachineOperatorGlobalCache;
  class Operator;
  
  
  // Supported write barrier modes.
  enum WriteBarrierKind { kNoWriteBarrier, kFullWriteBarrier };
  
  std::ostream& operator<<(std::ostream& os, WriteBarrierKind);
  
  
  // A Load needs a MachineType.
  typedef MachineType LoadRepresentation;
  
  
  // A Store needs a MachineType and a WriteBarrierKind in order to emit the
  // correct write barrier.
  class StoreRepresentation FINAL {
   public:
    StoreRepresentation(MachineType machine_type,
                        WriteBarrierKind write_barrier_kind)
        : machine_type_(machine_type), write_barrier_kind_(write_barrier_kind) {}
  
    MachineType machine_type() const { return machine_type_; }
    WriteBarrierKind write_barrier_kind() const { return write_barrier_kind_; }
  
   private:
    MachineType machine_type_;
    WriteBarrierKind write_barrier_kind_;
  };
  
  bool operator==(StoreRepresentation, StoreRepresentation);
  bool operator!=(StoreRepresentation, StoreRepresentation);
  
  size_t hash_value(StoreRepresentation);
  
  std::ostream& operator<<(std::ostream&, StoreRepresentation);
  
  StoreRepresentation const& StoreRepresentationOf(Operator const*);
  
  
  // A CheckedLoad needs a MachineType.
  typedef MachineType CheckedLoadRepresentation;
  
  CheckedLoadRepresentation CheckedLoadRepresentationOf(Operator const*);
  
  
  // A CheckedStore needs a MachineType.
  typedef MachineType CheckedStoreRepresentation;
  
  CheckedStoreRepresentation CheckedStoreRepresentationOf(Operator const*);
  
  
  // Interface for building machine-level operators. These operators are
  // machine-level but machine-independent and thus define a language suitable
  // for generating code to run on architectures such as ia32, x64, arm, etc.
  class MachineOperatorBuilder FINAL : public ZoneObject {
   public:
    // Flags that specify which operations are available. This is useful
    // for operations that are unsupported by some back-ends.
    enum Flag {
      kNoFlags = 0u,
      kFloat64Floor = 1u << 0,
      kFloat64Ceil = 1u << 1,
      kFloat64RoundTruncate = 1u << 2,
      kFloat64RoundTiesAway = 1u << 3,
      kInt32DivIsSafe = 1u << 4,
      kUint32DivIsSafe = 1u << 5,
      kWord32ShiftIsSafe = 1u << 6
    };
    typedef base::Flags<Flag, unsigned> Flags;
  
    explicit MachineOperatorBuilder(Zone* zone, MachineType word = kMachPtr,
                                    Flags supportedOperators = kNoFlags);
  
    const Operator* Word32And();
    const Operator* Word32Or();
    const Operator* Word32Xor();
    const Operator* Word32Shl();
    const Operator* Word32Shr();
    const Operator* Word32Sar();
    const Operator* Word32Ror();
    const Operator* Word32Equal();
    bool Word32ShiftIsSafe() const { return flags_ & kWord32ShiftIsSafe; }
  
    const Operator* Word64And();
    const Operator* Word64Or();
    const Operator* Word64Xor();
    const Operator* Word64Shl();
    const Operator* Word64Shr();
    const Operator* Word64Sar();
    const Operator* Word64Ror();
    const Operator* Word64Equal();
  
    const Operator* Int32Add();
    const Operator* Int32AddWithOverflow();
    const Operator* Int32Sub();
    const Operator* Int32SubWithOverflow();
    const Operator* Int32Mul();
    const Operator* Int32MulHigh();
    const Operator* Int32Div();
    const Operator* Int32Mod();
    const Operator* Int32LessThan();
    const Operator* Int32LessThanOrEqual();
    const Operator* Uint32Div();
    const Operator* Uint32LessThan();
    const Operator* Uint32LessThanOrEqual();
    const Operator* Uint32Mod();
    const Operator* Uint32MulHigh();
    bool Int32DivIsSafe() const { return flags_ & kInt32DivIsSafe; }
    bool Uint32DivIsSafe() const { return flags_ & kUint32DivIsSafe; }
  
    const Operator* Int64Add();
    const Operator* Int64Sub();
    const Operator* Int64Mul();
    const Operator* Int64Div();
    const Operator* Int64Mod();
    const Operator* Int64LessThan();
    const Operator* Int64LessThanOrEqual();
    const Operator* Uint64Div();
    const Operator* Uint64LessThan();
    const Operator* Uint64Mod();
  
    // These operators change the representation of numbers while preserving the
    // value of the number. Narrowing operators assume the input is representable
    // in the target type and are *not* defined for other inputs.
    // Use narrowing change operators only when there is a static guarantee that
    // the input value is representable in the target value.
    const Operator* ChangeFloat32ToFloat64();
    const Operator* ChangeFloat64ToInt32();   // narrowing
    const Operator* ChangeFloat64ToUint32();  // narrowing
    const Operator* ChangeInt32ToFloat64();
    const Operator* ChangeInt32ToInt64();
    const Operator* ChangeUint32ToFloat64();
    const Operator* ChangeUint32ToUint64();
  
    // These operators truncate numbers, both changing the representation of
    // the number and mapping multiple input values onto the same output value.
    const Operator* TruncateFloat64ToFloat32();
    const Operator* TruncateFloat64ToInt32();  // JavaScript semantics.
    const Operator* TruncateInt64ToInt32();
  
    // Floating point operators always operate with IEEE 754 round-to-nearest.
    const Operator* Float64Add();
    const Operator* Float64Sub();
    const Operator* Float64Mul();
    const Operator* Float64Div();
    const Operator* Float64Mod();
    const Operator* Float64Sqrt();
  
    // Floating point comparisons complying to IEEE 754.
    const Operator* Float64Equal();
    const Operator* Float64LessThan();
    const Operator* Float64LessThanOrEqual();
  
    // Floating point rounding.
    const Operator* Float64Floor();
    const Operator* Float64Ceil();
    const Operator* Float64RoundTruncate();
    const Operator* Float64RoundTiesAway();
    bool HasFloat64Floor() { return flags_ & kFloat64Floor; }
    bool HasFloat64Ceil() { return flags_ & kFloat64Ceil; }
    bool HasFloat64RoundTruncate() { return flags_ & kFloat64RoundTruncate; }
    bool HasFloat64RoundTiesAway() { return flags_ & kFloat64RoundTiesAway; }
  
    // load [base + index]
    const Operator* Load(LoadRepresentation rep);
  
    // store [base + index], value
    const Operator* Store(StoreRepresentation rep);
  
    // Access to the machine stack.
    const Operator* LoadStackPointer();
  
    // checked-load heap, index, length
    const Operator* CheckedLoad(CheckedLoadRepresentation);
    // checked-store heap, index, length, value
    const Operator* CheckedStore(CheckedStoreRepresentation);
  
    // Target machine word-size assumed by this builder.
    bool Is32() const { return word() == kRepWord32; }
    bool Is64() const { return word() == kRepWord64; }
    MachineType word() const { return word_; }
  
  // Pseudo operators that translate to 32/64-bit operators depending on the
  // word-size of the target machine assumed by this builder.
  #define PSEUDO_OP_LIST(V) \
    V(Word, And)            \
    V(Word, Or)             \
    V(Word, Xor)            \
    V(Word, Shl)            \
    V(Word, Shr)            \
    V(Word, Sar)            \
    V(Word, Ror)            \
    V(Word, Equal)          \
    V(Int, Add)             \
    V(Int, Sub)             \
    V(Int, Mul)             \
    V(Int, Div)             \
    V(Int, Mod)             \
    V(Int, LessThan)        \
    V(Int, LessThanOrEqual) \
    V(Uint, Div)            \
    V(Uint, LessThan)       \
    V(Uint, Mod)
  #define PSEUDO_OP(Prefix, Suffix)                                \
    const Operator* Prefix##Suffix() {                             \
      return Is32() ? Prefix##32##Suffix() : Prefix##64##Suffix(); \
    }
    PSEUDO_OP_LIST(PSEUDO_OP)
  #undef PSEUDO_OP
  #undef PSEUDO_OP_LIST
  
   private:
    Zone* zone_;
    const MachineOperatorGlobalCache& cache_;
    const MachineType word_;
    const Flags flags_;
    DISALLOW_COPY_AND_ASSIGN(MachineOperatorBuilder);
  };
  
  
  DEFINE_OPERATORS_FOR_FLAGS(MachineOperatorBuilder::Flags)
  }  // namespace compiler
  }  // namespace internal
  }  // namespace v8
  
  #endif  // V8_COMPILER_MACHINE_OPERATOR_H_
  