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 // We can't do better than to keep the offsets in a sorted vector.
42 // Here, offset is the key, and file_num/line_num is the value.
43 struct Offset_to_lineno_entry
46 int header_num; // which file-list to use (i.e. which .o file are we in)
47 int file_num; // a pointer into files_
48 int line_num; // the line number in the source file
49 // Offsets are unique within a section, so that's a sufficient sort key.
50 bool operator<(const Offset_to_lineno_entry& that) const
51 { return this->offset < that.offset; }
54 // This class is used to read the line information from the debugging
55 // section of an object file.
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)
73 { return do_addr2line(shndx, offset); }
75 // A helper function for a single addr2line lookup. It uses
76 // parameters() to figure out the size and endianness. This is less
77 // efficient than using the templatized size and endianness, so only
78 // call this from an un-templatized context.
80 one_addr2line(Object* object, unsigned int shndx, off_t offset);
84 do_addr2line(unsigned int shndx, off_t offset) = 0;
87 template<int size, bool big_endian>
88 class Sized_dwarf_line_info : public Dwarf_line_info
91 // Initializes a .debug_line reader for a given object file.
92 Sized_dwarf_line_info(Object* object);
96 do_addr2line(unsigned int shndx, off_t offset);
98 // Start processing line info, and populates the offset_map_.
100 read_line_mappings();
102 // Reads the relocation section associated with .debug_line and
103 // stores relocation information in reloc_map_.
107 // Looks in the symtab to see what section a symbol is in.
109 symbol_section(unsigned int sym,
110 typename elfcpp::Elf_types<size>::Elf_Addr* value);
112 // Reads the DWARF2/3 header for this line info. Each takes as input
113 // a starting buffer position, and returns the ending position.
115 read_header_prolog(const unsigned char* lineptr);
118 read_header_tables(const unsigned char* lineptr);
120 // Reads the DWARF2/3 line information.
122 read_lines(const unsigned char* lineptr);
124 // Process a single line info opcode at START using the state
125 // machine at LSM. Return true if we should define a line using the
126 // current state of the line state machine. Place the length of the
129 process_one_opcode(const unsigned char* start,
130 struct LineStateMachine* lsm, size_t* len);
132 // Some parts of processing differ depending on whether the input
133 // was a .o file or not.
134 bool input_is_relobj();
136 // If we saw anything amiss while parsing, we set this to false.
137 // Then addr2line will always fail (rather than return possibly-
141 // A DWARF2/3 line info header. This is not the same size as in the
142 // actual file, as the one in the file may have a 32 bit or 64 bit
145 struct Dwarf_line_infoHeader
149 off_t prologue_length;
150 int min_insn_length; // insn stands for instructin
151 bool default_is_stmt; // stmt stands for statement
152 signed char line_base;
154 unsigned char opcode_base;
155 std::vector<unsigned char> std_opcode_lengths;
159 // buffer is the buffer for our line info, starting at exactly where
160 // the line info to read is.
161 const unsigned char* buffer_;
162 const unsigned char* buffer_end_;
164 // This has relocations that point into buffer.
165 Track_relocs<size, big_endian> track_relocs_;
167 // This is used to figure out what section to apply a relocation to.
168 const unsigned char* symtab_buffer_;
169 off_t symtab_buffer_size_;
171 // Holds the directories and files as we see them. We have an array
172 // of directory-lists, one for each .o file we're reading (usually
173 // there will just be one, but there may be more if input is a .so).
174 std::vector<std::vector<std::string> > directories_;
175 // The first part is an index into directories_, the second the filename.
176 std::vector<std::vector< std::pair<int, std::string> > > files_;
178 // An index into the current directories_ and files_ vectors.
179 int current_header_index_;
181 // A sorted map from offset of the relocation target to the shndx
182 // and addend for the relocation.
183 typedef std::map<typename elfcpp::Elf_types<size>::Elf_Addr,
184 std::pair<unsigned int,
185 typename elfcpp::Elf_types<size>::Elf_Swxword> >
187 Reloc_map reloc_map_;
189 // We have a vector of offset->lineno entries for every input section.
190 typedef Unordered_map<unsigned int, std::vector<Offset_to_lineno_entry> >
193 Lineno_map line_number_map_;
196 } // End namespace gold.
198 #endif // !defined(GOLD_DWARF_READER_H)