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[binutils.git] / gold / dwarf_reader.h
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1 // dwarf_reader.h -- parse dwarf2/3 debug information for gold -*- C++ -*-
3 // Copyright 2007, 2008 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
26 #include <vector>
27 #include <map>
29 #include "elfcpp.h"
30 #include "elfcpp_swap.h"
31 #include "dwarf.h"
32 #include "reloc.h"
34 namespace gold
37 template<int size, bool big_endian>
38 class Track_relocs;
39 struct LineStateMachine;
41 uint64_t
42 read_unsigned_LEB_128(const unsigned char* buffer, size_t* len);
44 int64_t
45 read_signed_LEB_128(const unsigned char* buffer, size_t* len);
47 // We can't do better than to keep the offsets in a sorted vector.
48 // Here, offset is the key, and file_num/line_num is the value.
49 struct Offset_to_lineno_entry
51 off_t offset;
52 int header_num; // which file-list to use (i.e. which .o file are we in)
53 int file_num; // a pointer into files_
54 int line_num; // the line number in the source file
55 // Offsets are unique within a section, so that's a sufficient sort key.
56 bool operator<(const Offset_to_lineno_entry& that) const
57 { return this->offset < that.offset; }
60 // This class is used to read the line information from the debugging
61 // section of an object file.
63 class Dwarf_line_info
65 public:
66 Dwarf_line_info()
67 { }
69 virtual
70 ~Dwarf_line_info()
71 { }
73 // Given a section number and an offset, returns the associated
74 // file and line-number, as a string: "file:lineno". If unable
75 // to do the mapping, returns the empty string. You must call
76 // read_line_mappings() before calling this function.
77 std::string
78 addr2line(unsigned int shndx, off_t offset)
79 { return do_addr2line(shndx, offset); }
81 // A helper function for a single addr2line lookup. It also keeps a
82 // cache of the last CACHE_SIZE Dwarf_line_info objects it created;
83 // set to 0 not to cache at all. The larger CACHE_SIZE is, the more
84 // chance this routine won't have to re-create a Dwarf_line_info
85 // object for its addr2line computation; such creations are slow.
86 // NOTE: Not thread-safe, so only call from one thread at a time.
87 static std::string
88 one_addr2line(Object* object, unsigned int shndx, off_t offset,
89 size_t cache_size);
91 // This reclaims all the memory that one_addr2line may have cached.
92 // Use this when you know you will not be calling one_addr2line again.
93 static void
94 clear_addr2line_cache();
96 private:
97 virtual std::string
98 do_addr2line(unsigned int shndx, off_t offset) = 0;
101 template<int size, bool big_endian>
102 class Sized_dwarf_line_info : public Dwarf_line_info
104 public:
105 // Initializes a .debug_line reader for a given object file.
106 // If SHNDX is specified and non-negative, only read the debug
107 // information that pertains to the specified section.
108 Sized_dwarf_line_info(Object* object, off_t read_shndx = -1U);
110 private:
111 std::string
112 do_addr2line(unsigned int shndx, off_t offset);
114 // Start processing line info, and populates the offset_map_.
115 // If SHNDX is non-negative, only store debug information that
116 // pertains to the specified section.
117 void
118 read_line_mappings(Object*, off_t shndx);
120 // Reads the relocation section associated with .debug_line and
121 // stores relocation information in reloc_map_.
122 void
123 read_relocs(Object*);
125 // Looks in the symtab to see what section a symbol is in.
126 unsigned int
127 symbol_section(Object*, unsigned int sym,
128 typename elfcpp::Elf_types<size>::Elf_Addr* value,
129 bool* is_ordinary);
131 // Reads the DWARF2/3 header for this line info. Each takes as input
132 // a starting buffer position, and returns the ending position.
133 const unsigned char*
134 read_header_prolog(const unsigned char* lineptr);
136 const unsigned char*
137 read_header_tables(const unsigned char* lineptr);
139 // Reads the DWARF2/3 line information. If shndx is non-negative,
140 // discard all line information that doesn't pertain to the given
141 // section.
142 const unsigned char*
143 read_lines(const unsigned char* lineptr, off_t shndx);
145 // Process a single line info opcode at START using the state
146 // machine at LSM. Return true if we should define a line using the
147 // current state of the line state machine. Place the length of the
148 // opcode in LEN.
149 bool
150 process_one_opcode(const unsigned char* start,
151 struct LineStateMachine* lsm, size_t* len);
153 // Some parts of processing differ depending on whether the input
154 // was a .o file or not.
155 bool input_is_relobj();
157 // If we saw anything amiss while parsing, we set this to false.
158 // Then addr2line will always fail (rather than return possibly-
159 // corrupt data).
160 bool data_valid_;
162 // A DWARF2/3 line info header. This is not the same size as in the
163 // actual file, as the one in the file may have a 32 bit or 64 bit
164 // lengths.
166 struct Dwarf_line_infoHeader
168 off_t total_length;
169 int version;
170 off_t prologue_length;
171 int min_insn_length; // insn stands for instructin
172 bool default_is_stmt; // stmt stands for statement
173 signed char line_base;
174 int line_range;
175 unsigned char opcode_base;
176 std::vector<unsigned char> std_opcode_lengths;
177 int offset_size;
178 } header_;
180 // buffer is the buffer for our line info, starting at exactly where
181 // the line info to read is.
182 const unsigned char* buffer_;
183 const unsigned char* buffer_end_;
185 // This has relocations that point into buffer.
186 Track_relocs<size, big_endian> track_relocs_;
188 // This is used to figure out what section to apply a relocation to.
189 const unsigned char* symtab_buffer_;
190 section_size_type symtab_buffer_size_;
192 // Holds the directories and files as we see them. We have an array
193 // of directory-lists, one for each .o file we're reading (usually
194 // there will just be one, but there may be more if input is a .so).
195 std::vector<std::vector<std::string> > directories_;
196 // The first part is an index into directories_, the second the filename.
197 std::vector<std::vector< std::pair<int, std::string> > > files_;
199 // An index into the current directories_ and files_ vectors.
200 int current_header_index_;
202 // A sorted map from offset of the relocation target to the shndx
203 // and addend for the relocation.
204 typedef std::map<typename elfcpp::Elf_types<size>::Elf_Addr,
205 std::pair<unsigned int,
206 typename elfcpp::Elf_types<size>::Elf_Swxword> >
207 Reloc_map;
208 Reloc_map reloc_map_;
210 // We have a vector of offset->lineno entries for every input section.
211 typedef Unordered_map<unsigned int, std::vector<Offset_to_lineno_entry> >
212 Lineno_map;
214 Lineno_map line_number_map_;
217 } // End namespace gold.
219 #endif // !defined(GOLD_DWARF_READER_H)