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bae7f79e ILT |
1 | // fileread.h -- read files for gold -*- C++ -*- |
2 | ||
6cb15b7f ILT |
3 | // Copyright 2006, 2007 Free Software Foundation, Inc. |
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 | ||
bae7f79e ILT |
23 | // Classes used to read data from binary input files. |
24 | ||
25 | #ifndef GOLD_FILEREAD_H | |
26 | #define GOLD_FILEREAD_H | |
27 | ||
bae7f79e | 28 | #include <list> |
ead1e424 ILT |
29 | #include <map> |
30 | #include <string> | |
bae7f79e ILT |
31 | |
32 | #include "options.h" | |
17a1d0a9 | 33 | #include "token.h" |
bae7f79e ILT |
34 | |
35 | namespace gold | |
36 | { | |
37 | ||
38 | class Dirsearch; | |
bae7f79e ILT |
39 | class File_view; |
40 | ||
41 | // File_read manages a file descriptor for a file we are reading. We | |
42 | // close file descriptors if we run out of them, so this class reopens | |
43 | // the file as needed. | |
44 | ||
45 | class File_read | |
46 | { | |
47 | public: | |
48 | File_read() | |
17a1d0a9 ILT |
49 | : name_(), descriptor_(-1), size_(0), token_(false), views_(), |
50 | saved_views_(), contents_(NULL), mapped_bytes_(0), released_(true) | |
bae7f79e | 51 | { } |
5a6f7e2d | 52 | |
bae7f79e ILT |
53 | ~File_read(); |
54 | ||
55 | // Open a file. | |
56 | bool | |
17a1d0a9 | 57 | open(const Task*, const std::string& name); |
bae7f79e | 58 | |
5a6f7e2d ILT |
59 | // Pretend to open the file, but provide the file contents. No |
60 | // actual file system activity will occur. This is used for | |
61 | // testing. | |
62 | bool | |
17a1d0a9 ILT |
63 | open(const Task*, const std::string& name, const unsigned char* contents, |
64 | off_t size); | |
5a6f7e2d | 65 | |
bae7f79e ILT |
66 | // Return the file name. |
67 | const std::string& | |
68 | filename() const | |
69 | { return this->name_; } | |
70 | ||
17a1d0a9 ILT |
71 | // Lock the file for exclusive access within a particular Task::run |
72 | // execution. This means that the descriptor can not be closed. | |
73 | // This routine may only be called when the workqueue lock is held. | |
bae7f79e | 74 | void |
17a1d0a9 | 75 | lock(const Task* t); |
bae7f79e ILT |
76 | |
77 | // Unlock the descriptor, permitting it to be closed if necessary. | |
78 | void | |
17a1d0a9 | 79 | unlock(const Task* t); |
4973341a | 80 | |
bae7f79e ILT |
81 | // Test whether the object is locked. |
82 | bool | |
7004837e | 83 | is_locked() const; |
bae7f79e | 84 | |
17a1d0a9 ILT |
85 | // Return the token, so that the task can be queued. |
86 | Task_token* | |
87 | token() | |
88 | { return &this->token_; } | |
89 | ||
90 | // Release the file. This indicates that we aren't going to do | |
91 | // anything further with it until it is unlocked. This is used | |
92 | // because a Task which locks the file never calls either lock or | |
93 | // unlock; it just locks the token. The basic rule is that a Task | |
94 | // which locks a file via the Task::locks interface must explicitly | |
95 | // call release() when it is done. This is not necessary for code | |
96 | // which calls unlock() on the file. | |
97 | void | |
98 | release(); | |
99 | ||
82dcae9d ILT |
100 | // Return the size of the file. |
101 | off_t | |
102 | filesize() const | |
103 | { return this->size_; } | |
104 | ||
ba45d247 ILT |
105 | // Return a view into the file starting at file offset START for |
106 | // SIZE bytes. The pointer will remain valid until the File_read is | |
107 | // unlocked. It is an error if we can not read enough data from the | |
9eb9fa57 ILT |
108 | // file. The CACHE parameter is a hint as to whether it will be |
109 | // useful to cache this data for later accesses--i.e., later calls | |
110 | // to get_view, read, or get_lasting_view which retrieve the same | |
111 | // data. | |
bae7f79e | 112 | const unsigned char* |
9eb9fa57 | 113 | get_view(off_t start, off_t size, bool cache); |
bae7f79e | 114 | |
ba45d247 ILT |
115 | // Read data from the file into the buffer P starting at file offset |
116 | // START for SIZE bytes. | |
117 | void | |
c71c6f56 | 118 | read(off_t start, off_t size, void* p) const; |
ba45d247 | 119 | |
ba45d247 ILT |
120 | // Return a lasting view into the file starting at file offset START |
121 | // for SIZE bytes. This is allocated with new, and the caller is | |
122 | // responsible for deleting it when done. The data associated with | |
123 | // this view will remain valid until the view is deleted. It is an | |
9eb9fa57 ILT |
124 | // error if we can not read enough data from the file. The CACHE |
125 | // parameter is as in get_view. | |
bae7f79e | 126 | File_view* |
9eb9fa57 | 127 | get_lasting_view(off_t start, off_t size, bool cache); |
bae7f79e | 128 | |
e44fcf3b ILT |
129 | // Dump statistical information to stderr. |
130 | static void | |
131 | print_stats(); | |
132 | ||
bae7f79e ILT |
133 | private: |
134 | // This class may not be copied. | |
135 | File_read(const File_read&); | |
136 | File_read& operator=(const File_read&); | |
137 | ||
17a1d0a9 ILT |
138 | // Total bytes mapped into memory during the link. This variable |
139 | // may not be accurate when running multi-threaded. | |
e44fcf3b ILT |
140 | static unsigned long long total_mapped_bytes; |
141 | ||
142 | // Current number of bytes mapped into memory during the link. This | |
17a1d0a9 | 143 | // variable may not be accurate when running multi-threaded. |
e44fcf3b ILT |
144 | static unsigned long long current_mapped_bytes; |
145 | ||
146 | // High water mark of bytes mapped into memory during the link. | |
17a1d0a9 | 147 | // This variable may not be accurate when running multi-threaded. |
e44fcf3b ILT |
148 | static unsigned long long maximum_mapped_bytes; |
149 | ||
d1038c21 | 150 | // A view into the file. |
bae7f79e ILT |
151 | class View |
152 | { | |
153 | public: | |
d1038c21 ILT |
154 | View(off_t start, off_t size, const unsigned char* data, bool cache, |
155 | bool mapped) | |
9eb9fa57 | 156 | : start_(start), size_(size), data_(data), lock_count_(0), |
d1038c21 | 157 | cache_(cache), mapped_(mapped) |
bae7f79e ILT |
158 | { } |
159 | ||
160 | ~View(); | |
161 | ||
162 | off_t | |
163 | start() const | |
164 | { return this->start_; } | |
165 | ||
166 | off_t | |
167 | size() const | |
168 | { return this->size_; } | |
169 | ||
e214a02b | 170 | const unsigned char* |
bae7f79e ILT |
171 | data() const |
172 | { return this->data_; } | |
173 | ||
174 | void | |
175 | lock(); | |
176 | ||
177 | void | |
178 | unlock(); | |
179 | ||
180 | bool | |
181 | is_locked(); | |
182 | ||
9eb9fa57 ILT |
183 | void |
184 | set_cache() | |
185 | { this->cache_ = true; } | |
186 | ||
187 | bool | |
188 | should_cache() const | |
189 | { return this->cache_; } | |
190 | ||
bae7f79e ILT |
191 | private: |
192 | View(const View&); | |
193 | View& operator=(const View&); | |
194 | ||
195 | off_t start_; | |
196 | off_t size_; | |
e214a02b | 197 | const unsigned char* data_; |
bae7f79e | 198 | int lock_count_; |
9eb9fa57 | 199 | bool cache_; |
d1038c21 | 200 | bool mapped_; |
bae7f79e ILT |
201 | }; |
202 | ||
e44fcf3b | 203 | friend class View; |
bae7f79e ILT |
204 | friend class File_view; |
205 | ||
ead1e424 | 206 | // Find a view into the file. |
bae7f79e | 207 | View* |
c71c6f56 | 208 | find_view(off_t start, off_t size) const; |
bae7f79e | 209 | |
ead1e424 | 210 | // Read data from the file into a buffer. |
82dcae9d | 211 | void |
c71c6f56 | 212 | do_read(off_t start, off_t size, void* p) const; |
bae7f79e | 213 | |
ead1e424 | 214 | // Find or make a view into the file. |
bae7f79e | 215 | View* |
9eb9fa57 | 216 | find_or_make_view(off_t start, off_t size, bool cache); |
bae7f79e | 217 | |
ead1e424 | 218 | // Clear the file views. |
bae7f79e ILT |
219 | void |
220 | clear_views(bool); | |
221 | ||
ead1e424 ILT |
222 | // The size of a file page for buffering data. |
223 | static const off_t page_size = 8192; | |
224 | ||
225 | // Given a file offset, return the page offset. | |
226 | static off_t | |
227 | page_offset(off_t file_offset) | |
228 | { return file_offset & ~ (page_size - 1); } | |
229 | ||
230 | // Given a file size, return the size to read integral pages. | |
231 | static off_t | |
232 | pages(off_t file_size) | |
233 | { return (file_size + (page_size - 1)) & ~ (page_size - 1); } | |
234 | ||
235 | // The type of a mapping from page start to views. | |
236 | typedef std::map<off_t, View*> Views; | |
237 | ||
238 | // A simple list of Views. | |
239 | typedef std::list<View*> Saved_views; | |
240 | ||
241 | // File name. | |
bae7f79e | 242 | std::string name_; |
ead1e424 | 243 | // File descriptor. |
bae7f79e | 244 | int descriptor_; |
82dcae9d ILT |
245 | // File size. |
246 | off_t size_; | |
17a1d0a9 ILT |
247 | // A token used to lock the file. |
248 | Task_token token_; | |
ead1e424 ILT |
249 | // Buffered views into the file. |
250 | Views views_; | |
251 | // List of views which were locked but had to be removed from views_ | |
252 | // because they were not large enough. | |
253 | Saved_views saved_views_; | |
5a6f7e2d ILT |
254 | // Specified file contents. Used only for testing purposes. |
255 | const unsigned char* contents_; | |
e44fcf3b ILT |
256 | // Total amount of space mapped into memory. This is only changed |
257 | // while the file is locked. When we unlock the file, we transfer | |
258 | // the total to total_mapped_bytes, and reset this to zero. | |
259 | size_t mapped_bytes_; | |
17a1d0a9 ILT |
260 | // Whether the file was released. |
261 | bool released_; | |
bae7f79e ILT |
262 | }; |
263 | ||
264 | // A view of file data that persists even when the file is unlocked. | |
265 | // Callers should destroy these when no longer required. These are | |
266 | // obtained form File_read::get_lasting_view. They may only be | |
267 | // destroyed when the underlying File_read is locked. | |
268 | ||
269 | class File_view | |
270 | { | |
271 | public: | |
272 | // This may only be called when the underlying File_read is locked. | |
273 | ~File_view(); | |
274 | ||
275 | // Return a pointer to the data associated with this view. | |
276 | const unsigned char* | |
277 | data() const | |
278 | { return this->data_; } | |
279 | ||
280 | private: | |
281 | File_view(const File_view&); | |
282 | File_view& operator=(const File_view&); | |
283 | ||
284 | friend class File_read; | |
285 | ||
286 | // Callers have to get these via File_read::get_lasting_view. | |
287 | File_view(File_read& file, File_read::View* view, const unsigned char* data) | |
288 | : file_(file), view_(view), data_(data) | |
289 | { } | |
290 | ||
291 | File_read& file_; | |
292 | File_read::View* view_; | |
293 | const unsigned char* data_; | |
294 | }; | |
295 | ||
bae7f79e ILT |
296 | // All the information we hold for a single input file. This can be |
297 | // an object file, a shared library, or an archive. | |
298 | ||
299 | class Input_file | |
300 | { | |
301 | public: | |
5a6f7e2d | 302 | Input_file(const Input_file_argument* input_argument) |
e2aacd2c ILT |
303 | : input_argument_(input_argument), found_name_(), file_(), |
304 | is_in_sysroot_(false) | |
bae7f79e ILT |
305 | { } |
306 | ||
5a6f7e2d ILT |
307 | // Create an input file with the contents already provided. This is |
308 | // only used for testing. With this path, don't call the open | |
309 | // method. | |
17a1d0a9 ILT |
310 | Input_file(const Task*, const char* name, const unsigned char* contents, |
311 | off_t size); | |
5a6f7e2d | 312 | |
75f2446e ILT |
313 | // Open the file. If the open fails, this will report an error and |
314 | // return false. | |
315 | bool | |
17a1d0a9 | 316 | open(const General_options&, const Dirsearch&, const Task*); |
bae7f79e | 317 | |
e2aacd2c | 318 | // Return the name given by the user. For -lc this will return "c". |
bae7f79e ILT |
319 | const char* |
320 | name() const | |
5a6f7e2d | 321 | { return this->input_argument_->name(); } |
bae7f79e | 322 | |
e2aacd2c ILT |
323 | // Return the file name. For -lc this will return something like |
324 | // "/usr/lib/libc.so". | |
bae7f79e ILT |
325 | const std::string& |
326 | filename() const | |
327 | { return this->file_.filename(); } | |
328 | ||
e2aacd2c ILT |
329 | // Return the name under which we found the file, corresponding to |
330 | // the command line. For -lc this will return something like | |
331 | // "libc.so". | |
332 | const std::string& | |
333 | found_name() const | |
334 | { return this->found_name_; } | |
335 | ||
4973341a ILT |
336 | // Return the position dependent options. |
337 | const Position_dependent_options& | |
338 | options() const | |
339 | { return this->input_argument_->options(); } | |
340 | ||
341 | // Return the file. | |
bae7f79e ILT |
342 | File_read& |
343 | file() | |
344 | { return this->file_; } | |
345 | ||
7004837e ILT |
346 | const File_read& |
347 | file() const | |
348 | { return this->file_; } | |
349 | ||
ad2d6943 ILT |
350 | // Whether we found the file in a directory in the system root. |
351 | bool | |
352 | is_in_sysroot() const | |
353 | { return this->is_in_sysroot_; } | |
354 | ||
bae7f79e | 355 | private: |
ead1e424 ILT |
356 | Input_file(const Input_file&); |
357 | Input_file& operator=(const Input_file&); | |
358 | ||
ad2d6943 | 359 | // The argument from the command line. |
5a6f7e2d | 360 | const Input_file_argument* input_argument_; |
e2aacd2c ILT |
361 | // The name under which we opened the file. This is like the name |
362 | // on the command line, but -lc turns into libc.so (or whatever). | |
363 | // It only includes the full path if the path was on the command | |
364 | // line. | |
365 | std::string found_name_; | |
ad2d6943 | 366 | // The file after we open it. |
bae7f79e | 367 | File_read file_; |
ad2d6943 ILT |
368 | // Whether we found the file in a directory in the system root. |
369 | bool is_in_sysroot_; | |
bae7f79e ILT |
370 | }; |
371 | ||
372 | } // end namespace gold | |
373 | ||
374 | #endif // !defined(GOLD_FILEREAD_H) |