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 "lldb/lldb-defines.h" |
14 | #include "lldb/lldb-types.h" |
15 | #include <cassert> |
16 | #include <optional> |
17 | |
18 | namespace lldb_private::plugin { |
19 | namespace dwarf { |
20 | /// Identifies a DWARF debug info entry within a given Module. It contains three |
21 | /// "coordinates": |
22 | /// - file_index: identifies the separate stand alone debug info file |
23 | /// that is referred to by the main debug info file. This will be the |
24 | /// index of a DWO file for fission, or the .o file on mac when not |
25 | /// using a dSYM file. If this field is not set, then this references |
26 | /// a DIE inside the original object file. |
27 | /// - section: identifies the section of the debug info entry in the given file: |
28 | /// debug_info or debug_types. |
29 | /// - die_offset: The offset of the debug info entry as an absolute offset from |
30 | /// the beginning of the section specified in the section field. |
31 | class DIERef { |
32 | public: |
33 | enum Section : uint8_t { DebugInfo, DebugTypes }; |
34 | DIERef(std::optional<uint32_t> file_index, Section section, |
35 | dw_offset_t die_offset) |
36 | : m_die_offset(die_offset), m_file_index(file_index.value_or(u: 0)), |
37 | m_file_index_valid(file_index ? true : false), m_section(section) { |
38 | assert(this->file_index() == file_index && "File Index is out of range?" ); |
39 | } |
40 | |
41 | explicit DIERef(lldb::user_id_t uid) { |
42 | m_die_offset = uid & k_die_offset_mask; |
43 | m_file_index_valid = (uid & k_file_index_valid_bit) != 0; |
44 | m_file_index = m_file_index_valid |
45 | ? (uid >> k_die_offset_bit_size) & k_file_index_mask |
46 | : 0; |
47 | m_section = |
48 | (uid & k_section_bit) != 0 ? Section::DebugTypes : Section::DebugInfo; |
49 | } |
50 | |
51 | lldb::user_id_t get_id() const { |
52 | if (m_die_offset == k_die_offset_mask) |
53 | return LLDB_INVALID_UID; |
54 | |
55 | return lldb::user_id_t(file_index().value_or(u: 0)) << k_die_offset_bit_size | |
56 | die_offset() | (m_file_index_valid ? k_file_index_valid_bit : 0) | |
57 | (section() == Section::DebugTypes ? k_section_bit : 0); |
58 | } |
59 | |
60 | std::optional<uint32_t> file_index() const { |
61 | if (m_file_index_valid) |
62 | return m_file_index; |
63 | return std::nullopt; |
64 | } |
65 | |
66 | Section section() const { return static_cast<Section>(m_section); } |
67 | |
68 | dw_offset_t die_offset() const { return m_die_offset; } |
69 | |
70 | bool operator<(DIERef other) const { |
71 | if (m_file_index_valid != other.m_file_index_valid) |
72 | return m_file_index_valid < other.m_file_index_valid; |
73 | if (m_file_index_valid && (m_file_index != other.m_file_index)) |
74 | return m_file_index < other.m_file_index; |
75 | if (m_section != other.m_section) |
76 | return m_section < other.m_section; |
77 | return m_die_offset < other.m_die_offset; |
78 | } |
79 | |
80 | bool operator==(const DIERef &rhs) const { |
81 | return file_index() == rhs.file_index() && m_section == rhs.m_section && |
82 | m_die_offset == rhs.m_die_offset; |
83 | } |
84 | |
85 | bool operator!=(const DIERef &rhs) const { return !(*this == rhs); } |
86 | |
87 | /// Decode a serialized version of this object from data. |
88 | /// |
89 | /// \param data |
90 | /// The decoder object that references the serialized data. |
91 | /// |
92 | /// \param offset_ptr |
93 | /// A pointer that contains the offset from which the data will be decoded |
94 | /// from that gets updated as data gets decoded. |
95 | /// |
96 | /// \return |
97 | /// Returns a valid DIERef if decoding succeeded, std::nullopt if there was |
98 | /// unsufficient or invalid values that were decoded. |
99 | static std::optional<DIERef> (const DataExtractor &data, |
100 | lldb::offset_t *offset_ptr); |
101 | |
102 | /// Encode this object into a data encoder object. |
103 | /// |
104 | /// This allows this object to be serialized to disk. |
105 | /// |
106 | /// \param encoder |
107 | /// A data encoder object that serialized bytes will be encoded into. |
108 | /// |
109 | void Encode(DataEncoder &encoder) const; |
110 | |
111 | static constexpr uint64_t k_die_offset_bit_size = DW_DIE_OFFSET_MAX_BITSIZE; |
112 | static constexpr uint64_t k_file_index_bit_size = |
113 | 64 - DW_DIE_OFFSET_MAX_BITSIZE - /* size of control bits */ 2; |
114 | |
115 | static constexpr uint64_t k_file_index_valid_bit = |
116 | (1ull << (k_file_index_bit_size + k_die_offset_bit_size)); |
117 | static constexpr uint64_t k_section_bit = |
118 | (1ull << (k_file_index_bit_size + k_die_offset_bit_size + 1)); |
119 | static constexpr uint64_t |
120 | k_file_index_mask = (~0ull) >> (64 - k_file_index_bit_size); // 0x3fffff; |
121 | static constexpr uint64_t k_die_offset_mask = (~0ull) >> |
122 | (64 - k_die_offset_bit_size); |
123 | |
124 | private: |
125 | // Allow 2TB of .debug_info/.debug_types offset |
126 | dw_offset_t m_die_offset : k_die_offset_bit_size; |
127 | // Used for DWO index or for .o file index on mac |
128 | dw_offset_t m_file_index : k_file_index_bit_size; |
129 | // Set to 1 if m_file_index is a DWO number |
130 | dw_offset_t m_file_index_valid : 1; |
131 | // Set to 0 for .debug_info 1 for .debug_types, |
132 | dw_offset_t m_section : 1; |
133 | }; |
134 | static_assert(sizeof(DIERef) == 8); |
135 | |
136 | typedef std::vector<DIERef> DIEArray; |
137 | } // namespace dwarf |
138 | } // namespace lldb_private::plugin |
139 | |
140 | namespace llvm { |
141 | template <> struct format_provider<lldb_private::plugin::dwarf::DIERef> { |
142 | static void format(const lldb_private::plugin::dwarf::DIERef &ref, |
143 | raw_ostream &OS, StringRef Style); |
144 | }; |
145 | } // namespace llvm |
146 | |
147 | #endif // LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DIEREF_H |
148 | |