1 // dwarf_reader.h -- parse dwarf2/3 debug information for gold -*- C++ -*-
3 // Copyright 2007 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
23 #ifndef GOLD_DWARF_READER_H
24 #define GOLD_DWARF_READER_H
30 #include "elfcpp_swap.h"
36 template<int size, bool big_endian>
38 struct LineStateMachine;
40 // This class is used to read the line information from the debugging
41 // section of an object file.
43 template<int size, bool big_endian>
47 // Initializes a .debug_line reader. Buffer and buffer length point
48 // to the beginning and length of the line information to read.
49 // Reader is a ByteReader class that has the endianness set
51 Dwarf_line_info(const unsigned char* buffer, off_t buffer_length,
52 Track_relocs<size, big_endian>* track_relocs,
53 const unsigned char* symtab_buffer,
54 off_t symtab_buffer_length)
56 buffer_(buffer), buffer_end_(buffer + buffer_length),
57 track_relocs_(track_relocs),
58 symtab_buffer_(symtab_buffer),
59 symtab_buffer_end_(symtab_buffer + symtab_buffer_length),
60 directories_(1), files_(1)
63 // Start processing line info, and populates the offset_map_.
67 // Given a section number and an offset, returns the associated
68 // file and line-number, as a string: "file:lineno". If unable
69 // to do the mapping, returns the empty string. You must call
70 // read_line_mappings() before calling this function.
72 addr2line(unsigned int shndx, off_t offset);
75 // Reads the relocation section associated with .debug_line and
76 // stores relocation information in reloc_map_.
80 // Looks in the symtab to see what section a symbol is in.
82 symbol_section(unsigned int sym,
83 typename elfcpp::Elf_types<size>::Elf_Addr* value);
85 // Reads the DWARF2/3 header for this line info. Each takes as input
86 // a starting buffer position, and returns the ending position.
88 read_header_prolog(const unsigned char* lineptr);
91 read_header_tables(const unsigned char* lineptr);
93 // Reads the DWARF2/3 line information.
95 read_lines(const unsigned char* lineptr);
97 // Process a single line info opcode at START using the state
98 // machine at LSM. Return true if we should define a line using the
99 // current state of the line state machine. Place the length of the
102 process_one_opcode(const unsigned char* start,
103 struct LineStateMachine* lsm, size_t* len);
105 // If we saw anything amiss while parsing, we set this to false.
106 // Then addr2line will always fail (rather than return possibly-
110 // A DWARF2/3 line info header. This is not the same size as in the
111 // actual file, as the one in the file may have a 32 bit or 64 bit
114 struct Dwarf_line_infoHeader
118 off_t prologue_length;
119 int min_insn_length; // insn stands for instructin
120 bool default_is_stmt; // stmt stands for statement
121 signed char line_base;
123 unsigned char opcode_base;
124 std::vector<unsigned char> std_opcode_lengths;
128 // buffer is the buffer for our line info, starting at exactly where
129 // the line info to read is.
130 const unsigned char* buffer_;
131 const unsigned char* const buffer_end_;
133 // This has relocations that point into buffer.
134 Track_relocs<size, big_endian>* track_relocs_;
136 // This is used to figure out what section to apply a relocation to.
137 const unsigned char* const symtab_buffer_;
138 const unsigned char* const symtab_buffer_end_;
140 // Holds the directories and files as we see them.
141 std::vector<std::string> directories_;
142 // The first part is an index into directories_, the second the filename.
143 std::vector< std::pair<int, std::string> > files_;
145 // A map from offset of the relocation target to the shndx and
146 // addend for the relocation.
147 typedef std::map<typename elfcpp::Elf_types<size>::Elf_Addr,
148 std::pair<unsigned int,
149 typename elfcpp::Elf_types<size>::Elf_Swxword> >
151 Reloc_map reloc_map_;
153 // We can't do better than to keep the offsets in a sorted vector.
154 // Here, offset is the key, and file_num/line_num is the value.
155 struct Offset_to_lineno_entry
158 int file_num; // a pointer into files_
160 // Offsets are unique within a section, so that's a sufficient sort key.
161 bool operator<(const Offset_to_lineno_entry& that) const
162 { return this->offset < that.offset; }
164 // We have a vector of offset->lineno entries for every input section.
165 typedef Unordered_map<unsigned int, std::vector<Offset_to_lineno_entry> >
168 Lineno_map line_number_map_;
171 } // End namespace gold.
173 #endif // !defined(GOLD_DWARF_READER_H)