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"
37 template<int size, bool big_endian>
39 struct LineStateMachine;
41 // This class is used to read the line information from the debugging
42 // section of an object file.
44 template<int size, bool big_endian>
48 // Initializes a .debug_line reader for a given object file.
49 Dwarf_line_info(Sized_relobj<size, big_endian>* object);
51 // Given a section number and an offset, returns the associated
52 // file and line-number, as a string: "file:lineno". If unable
53 // to do the mapping, returns the empty string. You must call
54 // read_line_mappings() before calling this function.
56 addr2line(unsigned int shndx, off_t offset);
59 // Start processing line info, and populates the offset_map_.
63 // Reads the relocation section associated with .debug_line and
64 // stores relocation information in reloc_map_.
68 // Looks in the symtab to see what section a symbol is in.
70 symbol_section(unsigned int sym,
71 typename elfcpp::Elf_types<size>::Elf_Addr* value);
73 // Reads the DWARF2/3 header for this line info. Each takes as input
74 // a starting buffer position, and returns the ending position.
76 read_header_prolog(const unsigned char* lineptr);
79 read_header_tables(const unsigned char* lineptr);
81 // Reads the DWARF2/3 line information.
83 read_lines(const unsigned char* lineptr);
85 // Process a single line info opcode at START using the state
86 // machine at LSM. Return true if we should define a line using the
87 // current state of the line state machine. Place the length of the
90 process_one_opcode(const unsigned char* start,
91 struct LineStateMachine* lsm, size_t* len);
93 // If we saw anything amiss while parsing, we set this to false.
94 // Then addr2line will always fail (rather than return possibly-
98 // A DWARF2/3 line info header. This is not the same size as in the
99 // actual file, as the one in the file may have a 32 bit or 64 bit
102 struct Dwarf_line_infoHeader
106 off_t prologue_length;
107 int min_insn_length; // insn stands for instructin
108 bool default_is_stmt; // stmt stands for statement
109 signed char line_base;
111 unsigned char opcode_base;
112 std::vector<unsigned char> std_opcode_lengths;
116 // buffer is the buffer for our line info, starting at exactly where
117 // the line info to read is.
118 const unsigned char* buffer_;
119 const unsigned char* buffer_end_;
121 // This has relocations that point into buffer.
122 Track_relocs<size, big_endian> track_relocs_;
124 // This is used to figure out what section to apply a relocation to.
125 const unsigned char* symtab_buffer_;
126 const unsigned char* symtab_buffer_end_;
128 // Holds the directories and files as we see them.
129 std::vector<std::string> directories_;
130 // The first part is an index into directories_, the second the filename.
131 std::vector< std::pair<int, std::string> > files_;
133 // A map from offset of the relocation target to the shndx and
134 // addend for the relocation.
135 typedef std::map<typename elfcpp::Elf_types<size>::Elf_Addr,
136 std::pair<unsigned int,
137 typename elfcpp::Elf_types<size>::Elf_Swxword> >
139 Reloc_map reloc_map_;
141 // We can't do better than to keep the offsets in a sorted vector.
142 // Here, offset is the key, and file_num/line_num is the value.
143 struct Offset_to_lineno_entry
146 int file_num; // a pointer into files_
148 // Offsets are unique within a section, so that's a sufficient sort key.
149 bool operator<(const Offset_to_lineno_entry& that) const
150 { return this->offset < that.offset; }
152 // We have a vector of offset->lineno entries for every input section.
153 typedef Unordered_map<unsigned int, std::vector<Offset_to_lineno_entry> >
156 Lineno_map line_number_map_;
159 } // End namespace gold.
161 #endif // !defined(GOLD_DWARF_READER_H)