bin/zxdb/symbols/base_type.h

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <stdint.h>

#include "garnet/bin/zxdb/symbols/type.h"

namespace zxdb {

// A DWARF "base type" is a compiler built-in primitive type like an
// integer. The file will include a definition for something named "int" that
// is defined as being a signed integer of 4 bytes, etc.
class BaseType final : public Type {
 public:
  // These are the DWARF base type encodings. The integer value of each is the
  // constant from the DWARF spec for that value. This isn't an enum because
  // the value is an integer that can include ranges of user-defined values.
  //
  // The DWARF list encompasses some types not generated by our toolchain,
  // and that other values can appear in symbols. Code is not expected to
  // handle every one of these values. To make it clear which values we handle,
  // the irrelevant values are removed. But code should not assume that only
  // these values might ever appear.
  static constexpr int kBaseTypeNone = 0x00;  // Means uninitialized.
  static constexpr int kBaseTypeAddress = 0x01;
  static constexpr int kBaseTypeBoolean = 0x02;
  static constexpr int kBaseTypeFloat = 0x04;
  static constexpr int kBaseTypeSigned = 0x05;
  static constexpr int kBaseTypeSignedChar = 0x06;
  static constexpr int kBaseTypeUnsigned = 0x07;
  static constexpr int kBaseTypeUnsignedChar = 0x08;
  static constexpr int kBaseTypeUTF = 0x10;  // Byte size defines encoding.

  // Symbol overrides.
  const BaseType* AsBaseType() const final;

  // Returns one of kBaseType* or possibly something else if the language is
  // new or unusual. Don't handle, but also don't crash on unexpected values.
  int base_type() const { return base_type_; }
  void set_base_type(int type) { base_type_ = type; }

  // Bitfield support.
  uint32_t bit_size() const { return bit_size_; }
  void set_bit_size(uint32_t bs) { bit_size_ = bs; }

  // DWARF defines the bit offset as the "number of bits from the beginning of
  // the containing entity to the beginning of the data member." The bit size
  // will be 0 for non-bitfields.
  uint32_t bit_offset() const { return bit_offset_; }
  void set_bit_offset(uint32_t bo) { bit_offset_ = bo; }

 private:
  FRIEND_REF_COUNTED_THREAD_SAFE(BaseType);
  FRIEND_MAKE_REF_COUNTED(BaseType);

  BaseType();
  BaseType(int base_type, int byte_size, const std::string& name);
  ~BaseType();

  int base_type_ = kBaseTypeNone;
  int bit_size_ = 0;
  int bit_offset_ = 0;
};

}  // namespace zxdb