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1 | // dwarf_reader.h -- parse dwarf2/3 debug information for gold -*- C++ -*- |
2 | ||
ebdbb458 | 3 | // Copyright 2007, 2008 Free Software Foundation, Inc. |
5c2c6c95 ILT |
4 | // Written by Ian Lance Taylor <iant@google.com>. |
5 | ||
6 | // This file is part of gold. | |
7 | ||
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. | |
12 | ||
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. | |
17 | ||
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. | |
22 | ||
23 | #ifndef GOLD_DWARF_READER_H | |
24 | #define GOLD_DWARF_READER_H | |
25 | ||
26 | #include <vector> | |
4c50553d | 27 | #include <map> |
5c2c6c95 | 28 | |
4c50553d | 29 | #include "elfcpp.h" |
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30 | #include "elfcpp_swap.h" |
31 | #include "dwarf.h" | |
24badc65 | 32 | #include "reloc.h" |
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33 | |
34 | namespace gold | |
35 | { | |
36 | ||
4c50553d ILT |
37 | template<int size, bool big_endian> |
38 | class Track_relocs; | |
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39 | struct LineStateMachine; |
40 | ||
62b01cb5 ILT |
41 | uint64_t |
42 | read_unsigned_LEB_128(const unsigned char* buffer, size_t* len); | |
43 | ||
44 | int64_t | |
45 | read_signed_LEB_128(const unsigned char* buffer, size_t* len); | |
46 | ||
79e052ea ILT |
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 | |
50 | { | |
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; } | |
58 | }; | |
59 | ||
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60 | // This class is used to read the line information from the debugging |
61 | // section of an object file. | |
62 | ||
63 | class Dwarf_line_info | |
64 | { | |
65 | public: | |
a55ce7fe ILT |
66 | Dwarf_line_info() |
67 | { } | |
68 | ||
69 | virtual | |
70 | ~Dwarf_line_info() | |
71 | { } | |
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72 | |
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 | |
a55ce7fe ILT |
78 | addr2line(unsigned int shndx, off_t offset) |
79 | { return do_addr2line(shndx, offset); } | |
80 | ||
e4e5049b CS |
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. | |
a55ce7fe | 87 | static std::string |
e4e5049b CS |
88 | one_addr2line(Object* object, unsigned int shndx, off_t offset, |
89 | size_t cache_size); | |
90 | ||
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(); | |
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95 | |
96 | private: | |
a55ce7fe ILT |
97 | virtual std::string |
98 | do_addr2line(unsigned int shndx, off_t offset) = 0; | |
99 | }; | |
100 | ||
101 | template<int size, bool big_endian> | |
a18f2bd6 | 102 | class Sized_dwarf_line_info : public Dwarf_line_info |
a55ce7fe ILT |
103 | { |
104 | public: | |
105 | // Initializes a .debug_line reader for a given object file. | |
9430daf8 ILT |
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); | |
a55ce7fe | 109 | |
a55ce7fe ILT |
110 | private: |
111 | std::string | |
112 | do_addr2line(unsigned int shndx, off_t offset); | |
113 | ||
24badc65 | 114 | // Start processing line info, and populates the offset_map_. |
9430daf8 ILT |
115 | // If SHNDX is non-negative, only store debug information that |
116 | // pertains to the specified section. | |
24badc65 | 117 | void |
d491d34e | 118 | read_line_mappings(Object*, off_t shndx); |
24badc65 | 119 | |
4c50553d ILT |
120 | // Reads the relocation section associated with .debug_line and |
121 | // stores relocation information in reloc_map_. | |
122 | void | |
d491d34e | 123 | read_relocs(Object*); |
4c50553d ILT |
124 | |
125 | // Looks in the symtab to see what section a symbol is in. | |
126 | unsigned int | |
d491d34e ILT |
127 | symbol_section(Object*, unsigned int sym, |
128 | typename elfcpp::Elf_types<size>::Elf_Addr* value, | |
129 | bool* is_ordinary); | |
4c50553d | 130 | |
5c2c6c95 ILT |
131 | // Reads the DWARF2/3 header for this line info. Each takes as input |
132 | // a starting buffer position, and returns the ending position. | |
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133 | const unsigned char* |
134 | read_header_prolog(const unsigned char* lineptr); | |
135 | ||
136 | const unsigned char* | |
137 | read_header_tables(const unsigned char* lineptr); | |
138 | ||
9430daf8 ILT |
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. | |
5c2c6c95 | 142 | const unsigned char* |
9430daf8 | 143 | read_lines(const unsigned char* lineptr, off_t shndx); |
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144 | |
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 | |
e43872e9 | 150 | process_one_opcode(const unsigned char* start, |
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151 | struct LineStateMachine* lsm, size_t* len); |
152 | ||
af674d1d ILT |
153 | // Some parts of processing differ depending on whether the input |
154 | // was a .o file or not. | |
155 | bool input_is_relobj(); | |
156 | ||
4c50553d ILT |
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_; | |
161 | ||
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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. | |
165 | ||
166 | struct Dwarf_line_infoHeader | |
167 | { | |
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_; | |
179 | ||
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_; | |
24badc65 | 183 | const unsigned char* buffer_end_; |
5c2c6c95 | 184 | |
4c50553d | 185 | // This has relocations that point into buffer. |
24badc65 | 186 | Track_relocs<size, big_endian> track_relocs_; |
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187 | |
188 | // This is used to figure out what section to apply a relocation to. | |
24badc65 | 189 | const unsigned char* symtab_buffer_; |
8383303e | 190 | section_size_type symtab_buffer_size_; |
4c50553d | 191 | |
af674d1d ILT |
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_; | |
5c2c6c95 | 196 | // The first part is an index into directories_, the second the filename. |
af674d1d ILT |
197 | std::vector<std::vector< std::pair<int, std::string> > > files_; |
198 | ||
199 | // An index into the current directories_ and files_ vectors. | |
200 | int current_header_index_; | |
5c2c6c95 | 201 | |
af674d1d ILT |
202 | // A sorted map from offset of the relocation target to the shndx |
203 | // and addend for the relocation. | |
4c50553d ILT |
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_; | |
209 | ||
5c2c6c95 ILT |
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; | |
213 | ||
214 | Lineno_map line_number_map_; | |
215 | }; | |
216 | ||
217 | } // End namespace gold. | |
218 | ||
219 | #endif // !defined(GOLD_DWARF_READER_H) |