1 /* DWARF 2 debugging format support for GDB. 2 3 Copyright (C) 1994-2024 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 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. 11 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. 16 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/>. */ 19 20 #ifndef GDB_DWARF2_LINE_HEADER_H 21 #define GDB_DWARF2_LINE_HEADER_H 22 23 #include "dwarf2/types.h" 24 25 struct dwarf2_per_objfile; 26 27 /* dir_index is 1-based in DWARF 4 and before, and is 0-based in DWARF 5 and 28 later. */ 29 typedef int dir_index; 30 31 /* file_name_index is 1-based in DWARF 4 and before, and is 0-based in DWARF 5 32 and later. */ 33 typedef int file_name_index; 34 35 struct line_header; 36 37 struct file_entry 38 { 39 file_entry () = default; 40 41 file_entry (const char *name_, file_name_index index_, dir_index d_index_, 42 unsigned int mod_time_, unsigned int length_) 43 : name (name_), 44 index (index_), 45 d_index (d_index_), 46 mod_time (mod_time_), 47 length (length_) 48 {} 49 50 /* Return the include directory at D_INDEX stored in LH. Returns 51 NULL if D_INDEX is out of bounds. */ 52 const char *include_dir (const line_header *lh) const; 53 54 /* The file name. Note this is an observing pointer. The memory is 55 owned by debug_line_buffer. */ 56 const char *name {}; 57 58 /* The index of this file in the file table. */ 59 file_name_index index {}; 60 61 /* The directory index (1-based). */ 62 dir_index d_index {}; 63 64 unsigned int mod_time {}; 65 66 unsigned int length {}; 67 68 /* The associated symbol table, if any. */ 69 struct symtab *symtab {}; 70 }; 71 72 /* The line number information for a compilation unit (found in the 73 .debug_line section) begins with a "statement program header", 74 which contains the following information. */ 75 struct line_header 76 { 77 /* COMP_DIR is the value of the DW_AT_comp_dir attribute of the compilation 78 unit in the context of which we are reading this line header, or nullptr 79 if unknown or not applicable. */ 80 explicit line_header (const char *comp_dir) 81 : offset_in_dwz {}, m_comp_dir (comp_dir) 82 {} 83 84 /* This constructor should only be used to create line_header instances to do 85 hash table lookups. */ 86 line_header (sect_offset sect_off, bool offset_in_dwz) 87 : sect_off (sect_off), 88 offset_in_dwz (offset_in_dwz) 89 {} 90 91 /* Add an entry to the include directory table. */ 92 void add_include_dir (const char *include_dir); 93 94 /* Add an entry to the file name table. */ 95 void add_file_name (const char *name, dir_index d_index, 96 unsigned int mod_time, unsigned int length); 97 98 /* Return the include dir at INDEX (0-based in DWARF 5 and 1-based before). 99 Returns NULL if INDEX is out of bounds. */ 100 const char *include_dir_at (dir_index index) const 101 { 102 int vec_index; 103 if (version >= 5) 104 vec_index = index; 105 else 106 vec_index = index - 1; 107 if (vec_index < 0 || vec_index >= m_include_dirs.size ()) 108 return NULL; 109 return m_include_dirs[vec_index]; 110 } 111 112 bool is_valid_file_index (int file_index) const 113 { 114 if (version >= 5) 115 return 0 <= file_index && file_index < file_names_size (); 116 return 1 <= file_index && file_index <= file_names_size (); 117 } 118 119 /* Return the file name at INDEX (0-based in DWARF 5 and 1-based before). 120 Returns NULL if INDEX is out of bounds. */ 121 file_entry *file_name_at (file_name_index index) 122 { 123 int vec_index; 124 if (version >= 5) 125 vec_index = index; 126 else 127 vec_index = index - 1; 128 if (vec_index < 0 || vec_index >= m_file_names.size ()) 129 return NULL; 130 return &m_file_names[vec_index]; 131 } 132 133 /* A const overload of the same. */ 134 const file_entry *file_name_at (file_name_index index) const 135 { 136 line_header *lh = const_cast<line_header *> (this); 137 return lh->file_name_at (index); 138 } 139 140 /* The indexes are 0-based in DWARF 5 and 1-based in DWARF 4. Therefore, 141 this method should only be used to iterate through all file entries in an 142 index-agnostic manner. */ 143 std::vector<file_entry> &file_names () 144 { return m_file_names; } 145 /* A const overload of the same. */ 146 const std::vector<file_entry> &file_names () const 147 { return m_file_names; } 148 149 /* Offset of line number information in .debug_line section. */ 150 sect_offset sect_off {}; 151 152 /* OFFSET is for struct dwz_file associated with dwarf2_per_objfile. */ 153 unsigned offset_in_dwz : 1; /* Can't initialize bitfields in-class. */ 154 155 unsigned short version {}; 156 unsigned char minimum_instruction_length {}; 157 unsigned char maximum_ops_per_instruction {}; 158 unsigned char default_is_stmt {}; 159 int line_base {}; 160 unsigned char line_range {}; 161 unsigned char opcode_base {}; 162 163 /* standard_opcode_lengths[i] is the number of operands for the 164 standard opcode whose value is i. This means that 165 standard_opcode_lengths[0] is unused, and the last meaningful 166 element is standard_opcode_lengths[opcode_base - 1]. */ 167 std::unique_ptr<unsigned char[]> standard_opcode_lengths; 168 169 int file_names_size () const 170 { return m_file_names.size(); } 171 172 /* The start and end of the statement program following this 173 header. These point into dwarf2_per_objfile->line_buffer. */ 174 const gdb_byte *statement_program_start {}, *statement_program_end {}; 175 176 /* Return the most "complete" file name for FILE possible. 177 178 This means prepending the directory and compilation directory, as needed, 179 until we get an absolute path. */ 180 std::string file_file_name (const file_entry &fe) const; 181 182 /* Return the compilation directory of the compilation unit in the context of 183 which this line header is read. Return nullptr if non applicable. */ 184 const char *comp_dir () const 185 { return m_comp_dir; } 186 187 private: 188 /* The include_directories table. Note these are observing 189 pointers. The memory is owned by debug_line_buffer. */ 190 std::vector<const char *> m_include_dirs; 191 192 /* The file_names table. This is private because the meaning of indexes 193 differs among DWARF versions (The first valid index is 1 in DWARF 4 and 194 before, and is 0 in DWARF 5 and later). So the client should use 195 file_name_at method for access. */ 196 std::vector<file_entry> m_file_names; 197 198 /* Compilation directory of the compilation unit in the context of which this 199 line header is read. nullptr if unknown or not applicable. */ 200 const char *m_comp_dir = nullptr; 201 }; 202 203 typedef std::unique_ptr<line_header> line_header_up; 204 205 inline const char * 206 file_entry::include_dir (const line_header *lh) const 207 { 208 return lh->include_dir_at (d_index); 209 } 210 211 /* Read the statement program header starting at SECT_OFF in SECTION. 212 Return line_header. Returns nullptr if there is a problem reading 213 the header, e.g., if it has a version we don't understand. 214 215 NOTE: the strings in the include directory and file name tables of 216 the returned object point into the dwarf line section buffer, 217 and must not be freed. */ 218 219 extern line_header_up dwarf_decode_line_header 220 (sect_offset sect_off, bool is_dwz, dwarf2_per_objfile *per_objfile, 221 struct dwarf2_section_info *section, const struct comp_unit_head *cu_header, 222 const char *comp_dir); 223 224 #endif /* GDB_DWARF2_LINE_HEADER_H */ 225
Indexes created Mon Jul 20 00:27:07 UTC 2026