1 /* DWARF 2 debugging format support for GDB.
3 Copyright (C) 1994-2023 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 #ifndef DWARF2_LINE_HEADER_H
21 #define DWARF2_LINE_HEADER_H
23 /* dir_index is 1-based in DWARF 4 and before, and is 0-based in DWARF 5 and
25 typedef int dir_index
;
27 /* file_name_index is 1-based in DWARF 4 and before, and is 0-based in DWARF 5
29 typedef int file_name_index
;
35 file_entry () = default;
37 file_entry (const char *name_
, file_name_index index_
, dir_index d_index_
,
38 unsigned int mod_time_
, unsigned int length_
)
46 /* Return the include directory at D_INDEX stored in LH. Returns
47 NULL if D_INDEX is out of bounds. */
48 const char *include_dir (const line_header
*lh
) const;
50 /* The file name. Note this is an observing pointer. The memory is
51 owned by debug_line_buffer. */
54 /* The index of this file in the file table. */
55 file_name_index index
{};
57 /* The directory index (1-based). */
60 unsigned int mod_time
{};
62 unsigned int length
{};
64 /* The associated symbol table, if any. */
65 struct symtab
*symtab
{};
68 /* The line number information for a compilation unit (found in the
69 .debug_line section) begins with a "statement program header",
70 which contains the following information. */
73 /* COMP_DIR is the value of the DW_AT_comp_dir attribute of the compilation
74 unit in the context of which we are reading this line header, or nullptr
75 if unknown or not applicable. */
76 explicit line_header (const char *comp_dir
)
77 : offset_in_dwz
{}, m_comp_dir (comp_dir
)
80 /* This constructor should only be used to create line_header instances to do
81 hash table lookups. */
82 line_header (sect_offset sect_off
, bool offset_in_dwz
)
83 : sect_off (sect_off
),
84 offset_in_dwz (offset_in_dwz
)
87 /* Add an entry to the include directory table. */
88 void add_include_dir (const char *include_dir
);
90 /* Add an entry to the file name table. */
91 void add_file_name (const char *name
, dir_index d_index
,
92 unsigned int mod_time
, unsigned int length
);
94 /* Return the include dir at INDEX (0-based in DWARF 5 and 1-based before).
95 Returns NULL if INDEX is out of bounds. */
96 const char *include_dir_at (dir_index index
) const
102 vec_index
= index
- 1;
103 if (vec_index
< 0 || vec_index
>= m_include_dirs
.size ())
105 return m_include_dirs
[vec_index
];
108 bool is_valid_file_index (int file_index
) const
111 return 0 <= file_index
&& file_index
< file_names_size ();
112 return 1 <= file_index
&& file_index
<= file_names_size ();
115 /* Return the file name at INDEX (0-based in DWARF 5 and 1-based before).
116 Returns NULL if INDEX is out of bounds. */
117 file_entry
*file_name_at (file_name_index index
)
123 vec_index
= index
- 1;
124 if (vec_index
< 0 || vec_index
>= m_file_names
.size ())
126 return &m_file_names
[vec_index
];
129 /* A const overload of the same. */
130 const file_entry
*file_name_at (file_name_index index
) const
132 line_header
*lh
= const_cast<line_header
*> (this);
133 return lh
->file_name_at (index
);
136 /* The indexes are 0-based in DWARF 5 and 1-based in DWARF 4. Therefore,
137 this method should only be used to iterate through all file entries in an
138 index-agnostic manner. */
139 std::vector
<file_entry
> &file_names ()
140 { return m_file_names
; }
141 /* A const overload of the same. */
142 const std::vector
<file_entry
> &file_names () const
143 { return m_file_names
; }
145 /* Offset of line number information in .debug_line section. */
146 sect_offset sect_off
{};
148 /* OFFSET is for struct dwz_file associated with dwarf2_per_objfile. */
149 unsigned offset_in_dwz
: 1; /* Can't initialize bitfields in-class. */
151 unsigned short version
{};
152 unsigned char minimum_instruction_length
{};
153 unsigned char maximum_ops_per_instruction
{};
154 unsigned char default_is_stmt
{};
156 unsigned char line_range
{};
157 unsigned char opcode_base
{};
159 /* standard_opcode_lengths[i] is the number of operands for the
160 standard opcode whose value is i. This means that
161 standard_opcode_lengths[0] is unused, and the last meaningful
162 element is standard_opcode_lengths[opcode_base - 1]. */
163 std::unique_ptr
<unsigned char[]> standard_opcode_lengths
;
165 int file_names_size () const
166 { return m_file_names
.size(); }
168 /* The start and end of the statement program following this
169 header. These point into dwarf2_per_objfile->line_buffer. */
170 const gdb_byte
*statement_program_start
{}, *statement_program_end
{};
172 /* Return the most "complete" file name for FILE possible.
174 This means prepending the directory and compilation directory, as needed,
175 until we get an absolute path. */
176 std::string
file_file_name (const file_entry
&fe
) const;
178 /* Return the compilation directory of the compilation unit in the context of
179 which this line header is read. Return nullptr if non applicable. */
180 const char *comp_dir () const
181 { return m_comp_dir
; }
184 /* The include_directories table. Note these are observing
185 pointers. The memory is owned by debug_line_buffer. */
186 std::vector
<const char *> m_include_dirs
;
188 /* The file_names table. This is private because the meaning of indexes
189 differs among DWARF versions (The first valid index is 1 in DWARF 4 and
190 before, and is 0 in DWARF 5 and later). So the client should use
191 file_name_at method for access. */
192 std::vector
<file_entry
> m_file_names
;
194 /* Compilation directory of the compilation unit in the context of which this
195 line header is read. nullptr if unknown or not applicable. */
196 const char *m_comp_dir
= nullptr;
199 typedef std::unique_ptr
<line_header
> line_header_up
;
202 file_entry::include_dir (const line_header
*lh
) const
204 return lh
->include_dir_at (d_index
);
207 /* Read the statement program header starting at SECT_OFF in SECTION.
208 Return line_header. Returns nullptr if there is a problem reading
209 the header, e.g., if it has a version we don't understand.
211 NOTE: the strings in the include directory and file name tables of
212 the returned object point into the dwarf line section buffer,
213 and must not be freed. */
215 extern line_header_up dwarf_decode_line_header
216 (sect_offset sect_off
, bool is_dwz
, dwarf2_per_objfile
*per_objfile
,
217 struct dwarf2_section_info
*section
, const struct comp_unit_head
*cu_header
,
218 const char *comp_dir
);
220 #endif /* DWARF2_LINE_HEADER_H */