1//===-- DIERef.h ------------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DIEREF_H
10#define LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DIEREF_H
11
12#include "lldb/Core/dwarf.h"
13#include "llvm/Support/FormatProviders.h"
14#include <cassert>
15#include <optional>
16#include <vector>
17
18/// Identifies a DWARF debug info entry within a given Module. It contains three
19/// "coordinates":
20/// - dwo_num: identifies the dwo file in the Module. If this field is not set,
21///   the DIERef references the main file.
22/// - section: identifies the section of the debug info entry in the given file:
23///   debug_info or debug_types.
24/// - die_offset: The offset of the debug info entry as an absolute offset from
25///   the beginning of the section specified in the section field.
26class DIERef {
27public:
28  enum Section : uint8_t { DebugInfo, DebugTypes };
29
30  DIERef(std::optional<uint32_t> dwo_num, Section section,
31         dw_offset_t die_offset)
32      : m_dwo_num(dwo_num.value_or(0)), m_dwo_num_valid(bool(dwo_num)),
33        m_section(section), m_die_offset(die_offset) {
34    assert(this->dwo_num() == dwo_num && "Dwo number out of range?");
35  }
36
37  std::optional<uint32_t> dwo_num() const {
38    if (m_dwo_num_valid)
39      return m_dwo_num;
40    return std::nullopt;
41  }
42
43  Section section() const { return static_cast<Section>(m_section); }
44
45  dw_offset_t die_offset() const { return m_die_offset; }
46
47  bool operator<(DIERef other) const {
48    if (m_dwo_num_valid != other.m_dwo_num_valid)
49      return m_dwo_num_valid < other.m_dwo_num_valid;
50    if (m_dwo_num_valid && (m_dwo_num != other.m_dwo_num))
51      return m_dwo_num < other.m_dwo_num;
52    if (m_section != other.m_section)
53      return m_section < other.m_section;
54    return m_die_offset < other.m_die_offset;
55  }
56
57  bool operator==(const DIERef &rhs) const {
58    return dwo_num() == rhs.dwo_num() && m_section == rhs.m_section &&
59           m_die_offset == rhs.m_die_offset;
60  }
61
62  bool operator!=(const DIERef &rhs) const { return !(*this == rhs); }
63
64  /// Decode a serialized version of this object from data.
65  ///
66  /// \param data
67  ///   The decoder object that references the serialized data.
68  ///
69  /// \param offset_ptr
70  ///   A pointer that contains the offset from which the data will be decoded
71  ///   from that gets updated as data gets decoded.
72  ///
73  /// \return
74  ///   Returns a valid DIERef if decoding succeeded, std::nullopt if there was
75  ///   unsufficient or invalid values that were decoded.
76  static std::optional<DIERef> Decode(const lldb_private::DataExtractor &data,
77                                      lldb::offset_t *offset_ptr);
78
79  /// Encode this object into a data encoder object.
80  ///
81  /// This allows this object to be serialized to disk.
82  ///
83  /// \param encoder
84  ///   A data encoder object that serialized bytes will be encoded into.
85  ///
86  void Encode(lldb_private::DataEncoder &encoder) const;
87
88private:
89  uint32_t m_dwo_num : 30;
90  uint32_t m_dwo_num_valid : 1;
91  uint32_t m_section : 1;
92  dw_offset_t m_die_offset;
93};
94static_assert(sizeof(DIERef) == 8);
95
96typedef std::vector<DIERef> DIEArray;
97
98namespace llvm {
99template<> struct format_provider<DIERef> {
100  static void format(const DIERef &ref, raw_ostream &OS, StringRef Style);
101};
102} // namespace llvm
103
104#endif // LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DIEREF_H
105