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// 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_BYTECODE_REGISTER_H_
#define V8_INTERPRETER_BYTECODE_REGISTER_H_
#include "src/interpreter/bytecodes.h"
#include "src/base/macros.h"
#include "src/base/platform/platform.h"
#include "src/frame-constants.h"
#include "src/globals.h"
namespace v8 {
namespace internal {
namespace interpreter {
// An interpreter Register which is located in the function's Register file
// in its stack-frame. Register hold parameters, this, and expression values.
class V8_EXPORT_PRIVATE Register final {
public:
explicit Register(int index = kInvalidIndex) : index_(index) {}
int index() const { return index_; }
bool is_parameter() const { return index() < 0; }
bool is_valid() const { return index_ != kInvalidIndex; }
static Register FromParameterIndex(int index, int parameter_count);
int ToParameterIndex(int parameter_count) const;
// Returns an invalid register.
static Register invalid_value() { return Register(); }
// Returns the register for the function's closure object.
static Register function_closure();
bool is_function_closure() const;
// Returns the register which holds the current context object.
static Register current_context();
bool is_current_context() 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 = invalid_value(),
Register reg4 = invalid_value(),
Register reg5 = invalid_value());
std::string ToString(int parameter_count) const;
bool operator==(const Register& other) const {
return index() == other.index();
}
bool operator!=(const Register& other) const {
return index() != other.index();
}
bool operator<(const Register& other) const {
return index() < other.index();
}
bool operator<=(const Register& other) const {
return index() <= other.index();
}
bool operator>(const Register& other) const {
return index() > other.index();
}
bool operator>=(const Register& other) const {
return index() >= other.index();
}
private:
DISALLOW_NEW_AND_DELETE()
static const int kInvalidIndex = kMaxInt;
static const int kRegisterFileStartOffset =
InterpreterFrameConstants::kRegisterFileFromFp / kSystemPointerSize;
int index_;
};
class RegisterList {
public:
RegisterList()
: first_reg_index_(Register::invalid_value().index()),
register_count_(0) {}
explicit RegisterList(Register r) : RegisterList(r.index(), 1) {}
// Returns a new RegisterList which is a truncated version of this list, with
// |count| registers.
const RegisterList Truncate(int new_count) {
DCHECK_GE(new_count, 0);
DCHECK_LT(new_count, register_count_);
return RegisterList(first_reg_index_, new_count);
}
const Register operator[](size_t i) const {
DCHECK_LT(static_cast<int>(i), register_count_);
return Register(first_reg_index_ + static_cast<int>(i));
}
const Register first_register() const {
return (register_count() == 0) ? Register(0) : (*this)[0];
}
const Register last_register() const {
return (register_count() == 0) ? Register(0) : (*this)[register_count_ - 1];
}
int register_count() const { return register_count_; }
private:
friend class BytecodeRegisterAllocator;
friend class BytecodeDecoder;
friend class InterpreterTester;
friend class BytecodeUtils;
RegisterList(int first_reg_index, int register_count)
: first_reg_index_(first_reg_index), register_count_(register_count) {}
// Increases the size of the register list by one.
void IncrementRegisterCount() { register_count_++; }
int first_reg_index_;
int register_count_;
};
} // namespace interpreter
} // namespace internal
} // namespace v8
#endif // V8_INTERPRETER_BYTECODE_REGISTER_H_