1 | // -*- mode: c++ -*- |
2 | |
3 | // Copyright (c) 2010 Google Inc. |
4 | // All rights reserved. |
5 | // |
6 | // Redistribution and use in source and binary forms, with or without |
7 | // modification, are permitted provided that the following conditions are |
8 | // met: |
9 | // |
10 | // * Redistributions of source code must retain the above copyright |
11 | // notice, this list of conditions and the following disclaimer. |
12 | // * Redistributions in binary form must reproduce the above |
13 | // copyright notice, this list of conditions and the following disclaimer |
14 | // in the documentation and/or other materials provided with the |
15 | // distribution. |
16 | // * Neither the name of Google Inc. nor the names of its |
17 | // contributors may be used to endorse or promote products derived from |
18 | // this software without specific prior written permission. |
19 | // |
20 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
21 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
22 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
23 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
24 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
25 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
26 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
27 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
28 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
29 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
30 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
31 | |
32 | // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com> |
33 | |
34 | // The DwarfLineToModule class accepts line number information from a |
35 | // DWARF parser and adds it to a google_breakpad::Module. The Module |
36 | // can write that data out as a Breakpad symbol file. |
37 | |
38 | #ifndef COMMON_LINUX_DWARF_LINE_TO_MODULE_H |
39 | #define COMMON_LINUX_DWARF_LINE_TO_MODULE_H |
40 | |
41 | #include <string> |
42 | |
43 | #include "common/module.h" |
44 | #include "common/dwarf/dwarf2reader.h" |
45 | #include "common/using_std_string.h" |
46 | |
47 | namespace google_breakpad { |
48 | |
49 | // A class for producing a vector of google_breakpad::Module::Line |
50 | // instances from parsed DWARF line number data. |
51 | // |
52 | // An instance of this class can be provided as a handler to a |
53 | // LineInfo DWARF line number information parser. The |
54 | // handler accepts source location information from the parser and |
55 | // uses it to produce a vector of google_breakpad::Module::Line |
56 | // objects, referring to google_breakpad::Module::File objects added |
57 | // to a particular google_breakpad::Module. |
58 | // |
59 | // GNU toolchain omitted sections support: |
60 | // ====================================== |
61 | // |
62 | // Given the right options, the GNU toolchain will omit unreferenced |
63 | // functions from the final executable. Unfortunately, when it does so, it |
64 | // does not remove the associated portions of the DWARF line number |
65 | // program; instead, it gives the DW_LNE_set_address instructions referring |
66 | // to the now-deleted code addresses of zero. Given this input, the DWARF |
67 | // line parser will call AddLine with a series of lines starting at address |
68 | // zero. For example, here is the output from 'readelf -wl' for a program |
69 | // with four functions, the first three of which have been omitted: |
70 | // |
71 | // Line Number Statements: |
72 | // Extended opcode 2: set Address to 0x0 |
73 | // Advance Line by 14 to 15 |
74 | // Copy |
75 | // Special opcode 48: advance Address by 3 to 0x3 and Line by 1 to 16 |
76 | // Special opcode 119: advance Address by 8 to 0xb and Line by 2 to 18 |
77 | // Advance PC by 2 to 0xd |
78 | // Extended opcode 1: End of Sequence |
79 | // |
80 | // Extended opcode 2: set Address to 0x0 |
81 | // Advance Line by 14 to 15 |
82 | // Copy |
83 | // Special opcode 48: advance Address by 3 to 0x3 and Line by 1 to 16 |
84 | // Special opcode 119: advance Address by 8 to 0xb and Line by 2 to 18 |
85 | // Advance PC by 2 to 0xd |
86 | // Extended opcode 1: End of Sequence |
87 | // |
88 | // Extended opcode 2: set Address to 0x0 |
89 | // Advance Line by 19 to 20 |
90 | // Copy |
91 | // Special opcode 48: advance Address by 3 to 0x3 and Line by 1 to 21 |
92 | // Special opcode 76: advance Address by 5 to 0x8 and Line by 1 to 22 |
93 | // Advance PC by 2 to 0xa |
94 | // Extended opcode 1: End of Sequence |
95 | // |
96 | // Extended opcode 2: set Address to 0x80483a4 |
97 | // Advance Line by 23 to 24 |
98 | // Copy |
99 | // Special opcode 202: advance Address by 14 to 0x80483b2 and Line by 1 to 25 |
100 | // Special opcode 76: advance Address by 5 to 0x80483b7 and Line by 1 to 26 |
101 | // Advance PC by 6 to 0x80483bd |
102 | // Extended opcode 1: End of Sequence |
103 | // |
104 | // Instead of collecting runs of lines describing code that is not there, |
105 | // we try to recognize and drop them. Since the linker doesn't explicitly |
106 | // distinguish references to dropped sections from genuine references to |
107 | // code at address zero, we must use a heuristic. We have chosen: |
108 | // |
109 | // - If a line starts at address zero, omit it. (On the platforms |
110 | // breakpad targets, it is extremely unlikely that there will be code |
111 | // at address zero.) |
112 | // |
113 | // - If a line starts immediately after an omitted line, omit it too. |
114 | class DwarfLineToModule: public LineInfoHandler { |
115 | public: |
116 | // As the DWARF line info parser passes us line records, add source |
117 | // files to MODULE, and add all lines to the end of LINES. LINES |
118 | // need not be empty. If the parser hands us a zero-length line, we |
119 | // omit it. If the parser hands us a line that extends beyond the |
120 | // end of the address space, we clip it. It's up to our client to |
121 | // sort out which lines belong to which functions; we don't add them |
122 | // to any particular function in MODULE ourselves. |
123 | DwarfLineToModule(Module* module, |
124 | const string& compilation_dir, |
125 | vector<Module::Line>* lines, |
126 | std::map<uint32_t, Module::File*>* files) |
127 | : module_(module), |
128 | compilation_dir_(compilation_dir), |
129 | lines_(lines), |
130 | files_(files), |
131 | highest_file_number_(-1), |
132 | omitted_line_end_(0), |
133 | warned_bad_file_number_(false), |
134 | warned_bad_directory_number_(false) { } |
135 | |
136 | ~DwarfLineToModule() { } |
137 | |
138 | void DefineDir(const string& name, uint32_t dir_num); |
139 | void DefineFile(const string& name, int32_t file_num, |
140 | uint32_t dir_num, uint64_t mod_time, |
141 | uint64_t length); |
142 | void AddLine(uint64_t address, uint64_t length, |
143 | uint32_t file_num, uint32_t line_num, uint32_t column_num); |
144 | |
145 | private: |
146 | |
147 | typedef std::map<uint32_t, string> DirectoryTable; |
148 | typedef std::map<uint32_t, Module::File*> FileTable; |
149 | |
150 | // The module we're contributing debugging info to. Owned by our |
151 | // client. |
152 | Module *module_; |
153 | |
154 | // The compilation directory for the current compilation unit whose |
155 | // lines are being accumulated. |
156 | string compilation_dir_; |
157 | |
158 | // The vector of lines we're accumulating. Owned by our client. |
159 | // |
160 | // In a Module, as in a breakpad symbol file, lines belong to |
161 | // specific functions, but DWARF simply assigns lines to addresses; |
162 | // one must infer the line/function relationship using the |
163 | // functions' beginning and ending addresses. So we can't add these |
164 | // to the appropriate function from module_ until we've read the |
165 | // function info as well. Instead, we accumulate lines here, and let |
166 | // whoever constructed this sort it all out. |
167 | vector<Module::Line>* lines_; |
168 | |
169 | // A table mapping directory numbers to paths. |
170 | DirectoryTable directories_; |
171 | |
172 | // A table mapping file numbers to Module::File pointers. |
173 | FileTable* files_; |
174 | |
175 | // The highest file number we've seen so far, or -1 if we've seen |
176 | // none. Used for dynamically defined file numbers. |
177 | int32_t highest_file_number_; |
178 | |
179 | // This is the ending address of the last line we omitted, or zero if we |
180 | // didn't omit the previous line. It is zero before we have received any |
181 | // AddLine calls. |
182 | uint64_t omitted_line_end_; |
183 | |
184 | // True if we've warned about: |
185 | bool warned_bad_file_number_; // bad file numbers |
186 | bool warned_bad_directory_number_; // bad directory numbers |
187 | }; |
188 | |
189 | } // namespace google_breakpad |
190 | |
191 | #endif // COMMON_LINUX_DWARF_LINE_TO_MODULE_H |
192 | |