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dbe717ef ILT |
1 | // script.h -- handle linker scripts for gold -*- C++ -*- |
2 | ||
e5756efb | 3 | // Copyright 2006, 2007, 2008 Free Software Foundation, Inc. |
6cb15b7f 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 | ||
dbe717ef ILT |
23 | // We implement a subset of the original GNU ld linker script language |
24 | // for compatibility. The goal is not to implement the entire | |
25 | // language. It is merely to implement enough to handle common uses. | |
26 | // In particular we need to handle /usr/lib/libc.so on a typical | |
27 | // GNU/Linux system, and we want to handle linker scripts used by the | |
28 | // Linux kernel build. | |
29 | ||
30 | #ifndef GOLD_SCRIPT_H | |
31 | #define GOLD_SCRIPT_H | |
32 | ||
494e05f4 | 33 | #include <cstdio> |
04bf7072 | 34 | #include <string> |
e5756efb ILT |
35 | #include <vector> |
36 | ||
494e05f4 | 37 | #include "script-sections.h" |
09124467 | 38 | |
dbe717ef ILT |
39 | namespace gold |
40 | { | |
41 | ||
42 | class General_options; | |
3c2fafa5 | 43 | class Command_line; |
dbe717ef ILT |
44 | class Symbol_table; |
45 | class Layout; | |
7d9e3d98 | 46 | class Mapfile; |
3c2fafa5 | 47 | class Input_argument; |
072fe7ce | 48 | class Input_arguments; |
dbe717ef ILT |
49 | class Input_objects; |
50 | class Input_group; | |
51 | class Input_file; | |
a445fddf | 52 | class Output_segment; |
dbe717ef | 53 | class Task_token; |
3c2fafa5 | 54 | class Workqueue; |
494e05f4 ILT |
55 | struct Version_dependency_list; |
56 | struct Version_expression_list; | |
57 | struct Version_tree; | |
dbe717ef | 58 | |
e5756efb ILT |
59 | // This class represents an expression in a linker script. |
60 | ||
61 | class Expression | |
62 | { | |
63 | protected: | |
64 | // These should only be created by child classes. | |
65 | Expression() | |
66 | { } | |
67 | ||
68 | public: | |
69 | virtual ~Expression() | |
70 | { } | |
71 | ||
a445fddf | 72 | // Return the value of the expression which is not permitted to |
919ed24c ILT |
73 | // refer to the dot symbol. CHECK_ASSERTIONS is true if we should |
74 | // check whether assertions are true. | |
e5756efb | 75 | uint64_t |
919ed24c | 76 | eval(const Symbol_table*, const Layout*, bool check_assertions); |
e5756efb | 77 | |
a445fddf | 78 | // Return the value of an expression which is permitted to refer to |
77e65537 ILT |
79 | // the dot symbol. DOT_VALUE is the absolute value of the dot |
80 | // symbol. DOT_SECTION is the section in which dot is defined; it | |
81 | // should be NULL if the dot symbol has an absolute value (e.g., is | |
82 | // defined in a SECTIONS clause outside of any output section | |
83 | // definition). This sets *RESULT_SECTION to indicate where the | |
84 | // value is defined. If the value is absolute *RESULT_SECTION will | |
85 | // be NULL. Note that the returned value is still an absolute | |
86 | // value; to get a section relative value the caller must subtract | |
87 | // the section address. | |
a445fddf | 88 | uint64_t |
919ed24c ILT |
89 | eval_with_dot(const Symbol_table*, const Layout*, bool check_assertions, |
90 | uint64_t dot_value, Output_section* dot_section, | |
91 | Output_section** result_section); | |
a445fddf ILT |
92 | |
93 | // Return the value of an expression which may or may not be | |
94 | // permitted to refer to the dot symbol, depending on | |
95 | // is_dot_available. | |
96 | uint64_t | |
919ed24c ILT |
97 | eval_maybe_dot(const Symbol_table*, const Layout*, bool check_assertions, |
98 | bool is_dot_available, uint64_t dot_value, | |
99 | Output_section* dot_section, | |
77e65537 | 100 | Output_section** result_section); |
a445fddf | 101 | |
494e05f4 ILT |
102 | // Print the expression to the FILE. This is for debugging. |
103 | virtual void | |
104 | print(FILE*) const = 0; | |
105 | ||
e5756efb ILT |
106 | protected: |
107 | struct Expression_eval_info; | |
108 | ||
109 | public: | |
110 | // Compute the value of the expression (implemented by child class). | |
111 | // This is public rather than protected because it is called | |
112 | // directly by children of Expression on other Expression objects. | |
113 | virtual uint64_t | |
114 | value(const Expression_eval_info*) = 0; | |
115 | ||
116 | private: | |
117 | // May not be copied. | |
118 | Expression(const Expression&); | |
119 | Expression& operator=(const Expression&); | |
120 | }; | |
121 | ||
09124467 ILT |
122 | |
123 | // Version_script_info stores information parsed from the version | |
124 | // script, either provided by --version-script or as part of a linker | |
125 | // script. A single Version_script_info object per target is owned by | |
126 | // Script_options. | |
127 | ||
494e05f4 ILT |
128 | class Version_script_info |
129 | { | |
09124467 | 130 | public: |
6affe781 ILT |
131 | // The languages which can be specified in a versionn script. |
132 | enum Language | |
133 | { | |
134 | LANGUAGE_C, // No demangling. | |
135 | LANGUAGE_CXX, // C++ demangling. | |
136 | LANGUAGE_JAVA, // Java demangling. | |
137 | LANGUAGE_COUNT | |
138 | }; | |
139 | ||
140 | Version_script_info(); | |
141 | ||
09124467 ILT |
142 | ~Version_script_info(); |
143 | ||
1ef1f3d3 ILT |
144 | // Clear everything. |
145 | void | |
146 | clear(); | |
147 | ||
6affe781 ILT |
148 | // Finalize the version control information. |
149 | void | |
150 | finalize(); | |
151 | ||
152 | // Return whether the information is finalized. | |
153 | bool | |
154 | is_finalized() const | |
155 | { return this->is_finalized_; } | |
156 | ||
09124467 ILT |
157 | // Return whether any version were defined in the version script. |
158 | bool | |
159 | empty() const | |
160 | { return this->version_trees_.empty(); } | |
161 | ||
057ead22 ILT |
162 | // If there is a version associated with SYMBOL, return true, and |
163 | // set *VERSION to the version. Otherwise, return false. | |
164 | bool | |
165 | get_symbol_version(const char* symbol, std::string* version) const | |
166 | { return this->get_symbol_version_helper(symbol, true, version); } | |
167 | ||
168 | // Return whether this symbol matches the local: section of some | |
169 | // version. | |
09124467 ILT |
170 | bool |
171 | symbol_is_local(const char* symbol) const | |
057ead22 | 172 | { return this->get_symbol_version_helper(symbol, false, NULL); } |
09124467 ILT |
173 | |
174 | // Return the names of versions defined in the version script. | |
09124467 ILT |
175 | std::vector<std::string> |
176 | get_versions() const; | |
177 | ||
178 | // Return the list of dependencies for this version. | |
179 | std::vector<std::string> | |
180 | get_dependencies(const char* version) const; | |
181 | ||
182 | // The following functions should only be used by the bison helper | |
183 | // functions. They allocate new structs whose memory belongs to | |
184 | // Version_script_info. The bison functions copy the information | |
185 | // from the version script into these structs. | |
186 | struct Version_dependency_list* | |
187 | allocate_dependency_list(); | |
188 | ||
189 | struct Version_expression_list* | |
190 | allocate_expression_list(); | |
191 | ||
192 | struct Version_tree* | |
193 | allocate_version_tree(); | |
194 | ||
6affe781 ILT |
195 | // Build the lookup tables after all data have been read. |
196 | void | |
197 | build_lookup_tables(); | |
198 | ||
494e05f4 ILT |
199 | // Print contents to the FILE. This is for debugging. |
200 | void | |
201 | print(FILE*) const; | |
202 | ||
09124467 | 203 | private: |
494e05f4 ILT |
204 | void |
205 | print_expression_list(FILE* f, const Version_expression_list*) const; | |
206 | ||
6affe781 ILT |
207 | bool |
208 | get_symbol_version_helper(const char* symbol, | |
209 | bool check_global, | |
210 | std::string* pversion) const; | |
211 | ||
212 | // Fast lookup information for a glob pattern. | |
213 | struct Glob | |
214 | { | |
215 | Glob() | |
216 | : pattern(NULL), version(NULL) | |
217 | { } | |
218 | ||
219 | Glob(const char* p, const Version_tree* v) | |
220 | : pattern(p), version(v) | |
221 | { } | |
222 | ||
223 | // A pointer to the glob pattern. The pattern itself lives in a | |
224 | // Version_expression structure. | |
225 | const char* pattern; | |
226 | // The Version_tree we use if this pattern matches. | |
227 | const Version_tree* version; | |
228 | }; | |
229 | ||
230 | // Fast lookup information for a given language. | |
231 | ||
232 | typedef Unordered_map<std::string, const Version_tree*> Exact; | |
233 | ||
234 | struct Lookup | |
235 | { | |
236 | // A hash table of all exact match strings mapping to a | |
237 | // Version_tree. | |
238 | Exact exact; | |
239 | // A vector of glob patterns mapping to Version_trees. | |
240 | std::vector<Glob> globs; | |
241 | }; | |
09124467 | 242 | |
6affe781 ILT |
243 | void |
244 | build_expression_list_lookup(const Version_expression_list*, | |
245 | const Version_tree*, Lookup**); | |
246 | ||
247 | // All the version dependencies we allocate. | |
248 | std::vector<Version_dependency_list*> dependency_lists_; | |
249 | // All the version expressions we allocate. | |
250 | std::vector<Version_expression_list*> expression_lists_; | |
251 | // The list of versions. | |
252 | std::vector<Version_tree*> version_trees_; | |
253 | // Lookup information for global symbols, by language. | |
254 | Lookup* globals_[LANGUAGE_COUNT]; | |
255 | // Lookup information for local symbols, by language. | |
256 | Lookup* locals_[LANGUAGE_COUNT]; | |
257 | // Whether this has been finalized. | |
258 | bool is_finalized_; | |
09124467 ILT |
259 | }; |
260 | ||
494e05f4 ILT |
261 | // This class manages assignments to symbols. These can appear in |
262 | // three different locations in scripts: outside of a SECTIONS clause, | |
263 | // within a SECTIONS clause, and within an output section definition | |
264 | // within a SECTIONS clause. This can also appear on the command line | |
265 | // via the --defsym command line option. | |
266 | ||
267 | class Symbol_assignment | |
268 | { | |
269 | public: | |
99fff23b ILT |
270 | Symbol_assignment(const char* name, size_t namelen, bool is_defsym, |
271 | Expression* val, bool provide, bool hidden) | |
272 | : name_(name, namelen), val_(val), is_defsym_(is_defsym), | |
273 | provide_(provide), hidden_(hidden), sym_(NULL) | |
494e05f4 ILT |
274 | { } |
275 | ||
276 | // Add the symbol to the symbol table. | |
277 | void | |
9b07f471 | 278 | add_to_table(Symbol_table*); |
494e05f4 ILT |
279 | |
280 | // Finalize the symbol value. | |
a445fddf ILT |
281 | void |
282 | finalize(Symbol_table*, const Layout*); | |
283 | ||
284 | // Finalize the symbol value when it can refer to the dot symbol. | |
285 | void | |
77e65537 ILT |
286 | finalize_with_dot(Symbol_table*, const Layout*, uint64_t dot_value, |
287 | Output_section* dot_section); | |
a445fddf ILT |
288 | |
289 | // Set the symbol value, but only if the value is absolute. This is | |
77e65537 | 290 | // used while processing a SECTIONS clause. We assume that dot is |
919ed24c | 291 | // an absolute value here. We do not check assertions. |
a445fddf ILT |
292 | void |
293 | set_if_absolute(Symbol_table*, const Layout*, bool is_dot_available, | |
77e65537 | 294 | uint64_t dot_value); |
494e05f4 ILT |
295 | |
296 | // Print the assignment to the FILE. This is for debugging. | |
297 | void | |
298 | print(FILE*) const; | |
299 | ||
300 | private: | |
a445fddf ILT |
301 | // Shared by finalize and finalize_with_dot. |
302 | void | |
303 | finalize_maybe_dot(Symbol_table*, const Layout*, bool is_dot_available, | |
77e65537 | 304 | uint64_t dot_value, Output_section* dot_section); |
a445fddf | 305 | |
494e05f4 ILT |
306 | // Sized version of finalize. |
307 | template<int size> | |
308 | void | |
a445fddf | 309 | sized_finalize(Symbol_table*, const Layout*, bool is_dot_available, |
77e65537 | 310 | uint64_t dot_value, Output_section*); |
494e05f4 ILT |
311 | |
312 | // Symbol name. | |
313 | std::string name_; | |
314 | // Expression to assign to symbol. | |
315 | Expression* val_; | |
99fff23b ILT |
316 | // True if this symbol is defined by a --defsym, false if it is |
317 | // defined in a linker script. | |
318 | bool is_defsym_; | |
494e05f4 ILT |
319 | // Whether the assignment should be provided (only set if there is |
320 | // an undefined reference to the symbol. | |
321 | bool provide_; | |
322 | // Whether the assignment should be hidden. | |
323 | bool hidden_; | |
324 | // The entry in the symbol table. | |
325 | Symbol* sym_; | |
326 | }; | |
327 | ||
328 | // This class manages assertions in linker scripts. These can appear | |
329 | // in all the places where a Symbol_assignment can appear. | |
330 | ||
331 | class Script_assertion | |
332 | { | |
333 | public: | |
2ea97941 | 334 | Script_assertion(Expression* check, const char* message, |
494e05f4 | 335 | size_t messagelen) |
2ea97941 | 336 | : check_(check), message_(message, messagelen) |
494e05f4 ILT |
337 | { } |
338 | ||
339 | // Check the assertion. | |
340 | void | |
341 | check(const Symbol_table*, const Layout*); | |
342 | ||
343 | // Print the assertion to the FILE. This is for debugging. | |
344 | void | |
345 | print(FILE*) const; | |
346 | ||
347 | private: | |
348 | // The expression to check. | |
349 | Expression* check_; | |
350 | // The message to issue if the expression fails. | |
351 | std::string message_; | |
352 | }; | |
353 | ||
e5756efb ILT |
354 | // We can read a linker script in two different contexts: when |
355 | // initially parsing the command line, and when we find an input file | |
356 | // which is actually a linker script. Also some of the data which can | |
357 | // be set by a linker script can also be set via command line options | |
358 | // like -e and --defsym. This means that we have a type of data which | |
359 | // can be set both during command line option parsing and while | |
360 | // reading input files. We store that data in an instance of this | |
361 | // object. We will keep pointers to that instance in both the | |
362 | // Command_line and Layout objects. | |
363 | ||
364 | class Script_options | |
365 | { | |
366 | public: | |
367 | Script_options(); | |
368 | ||
494e05f4 | 369 | // Add a symbol to be defined. |
e5756efb | 370 | void |
99fff23b ILT |
371 | add_symbol_assignment(const char* name, size_t length, bool is_defsym, |
372 | Expression* value, bool provide, bool hidden); | |
494e05f4 ILT |
373 | |
374 | // Add an assertion. | |
375 | void | |
376 | add_assertion(Expression* check, const char* message, size_t messagelen); | |
e5756efb ILT |
377 | |
378 | // Define a symbol from the command line. | |
379 | bool | |
380 | define_symbol(const char* definition); | |
381 | ||
919ed24c ILT |
382 | // Create sections required by any linker scripts. |
383 | void | |
384 | create_script_sections(Layout*); | |
385 | ||
e5756efb ILT |
386 | // Add all symbol definitions to the symbol table. |
387 | void | |
9b07f471 | 388 | add_symbols_to_table(Symbol_table*); |
e5756efb | 389 | |
a445fddf | 390 | // Finalize the symbol values. Also check assertions. |
e5756efb ILT |
391 | void |
392 | finalize_symbols(Symbol_table*, const Layout*); | |
393 | ||
09124467 ILT |
394 | // Version information parsed from a version script. Everything |
395 | // else has a pointer to this object. | |
396 | Version_script_info* | |
397 | version_script_info() | |
494e05f4 | 398 | { return &this->version_script_info_; } |
09124467 | 399 | |
a5dc0706 ILT |
400 | const Version_script_info* |
401 | version_script_info() const | |
402 | { return &this->version_script_info_; } | |
403 | ||
494e05f4 ILT |
404 | // A SECTIONS clause parsed from a linker script. Everything else |
405 | // has a pointer to this object. | |
406 | Script_sections* | |
407 | script_sections() | |
408 | { return &this->script_sections_; } | |
e5756efb | 409 | |
8f2eb564 ILT |
410 | const Script_sections* |
411 | script_sections() const | |
412 | { return &this->script_sections_; } | |
413 | ||
a445fddf ILT |
414 | // Whether we saw a SECTIONS clause. |
415 | bool | |
416 | saw_sections_clause() const | |
417 | { return this->script_sections_.saw_sections_clause(); } | |
418 | ||
1c4f3631 ILT |
419 | // Whether we saw a PHDRS clause. |
420 | bool | |
421 | saw_phdrs_clause() const | |
422 | { return this->script_sections_.saw_phdrs_clause(); } | |
423 | ||
a445fddf ILT |
424 | // Set section addresses using a SECTIONS clause. Return the |
425 | // segment which should hold the file header and segment headers; | |
426 | // this may return NULL, in which case the headers are not in a | |
427 | // loadable segment. | |
428 | Output_segment* | |
429 | set_section_addresses(Symbol_table*, Layout*); | |
430 | ||
494e05f4 | 431 | // Print the script to the FILE. This is for debugging. |
e5756efb | 432 | void |
494e05f4 ILT |
433 | print(FILE*) const; |
434 | ||
435 | private: | |
436 | // We keep a list of symbol assignments which occur outside of a | |
437 | // SECTIONS clause. | |
438 | typedef std::vector<Symbol_assignment*> Symbol_assignments; | |
439 | ||
440 | // We keep a list of all assertions whcih occur outside of a | |
441 | // SECTIONS clause. | |
442 | typedef std::vector<Script_assertion*> Assertions; | |
e5756efb ILT |
443 | |
444 | // The entry address. This will be empty if not set. | |
445 | std::string entry_; | |
446 | // Symbols to set. | |
447 | Symbol_assignments symbol_assignments_; | |
494e05f4 ILT |
448 | // Assertions to check. |
449 | Assertions assertions_; | |
09124467 ILT |
450 | // Version information parsed from a version script. |
451 | Version_script_info version_script_info_; | |
494e05f4 ILT |
452 | // Information from any SECTIONS clauses. |
453 | Script_sections script_sections_; | |
e5756efb ILT |
454 | }; |
455 | ||
072fe7ce ILT |
456 | // Information about a script input that will persist during the whole linker |
457 | // run. Needed only during an incremental build to retrieve the input files | |
458 | // added by this script. | |
459 | ||
460 | class Script_info | |
461 | { | |
462 | public: | |
2ea97941 ILT |
463 | Script_info(Input_arguments* inputs) |
464 | : inputs_(inputs) | |
072fe7ce ILT |
465 | { } |
466 | ||
467 | // Returns the input files included because of this script. | |
468 | Input_arguments* | |
469 | inputs() | |
98fa85cb | 470 | { return this->inputs_; } |
072fe7ce ILT |
471 | |
472 | private: | |
473 | Input_arguments* inputs_; | |
474 | }; | |
475 | ||
dbe717ef | 476 | // FILE was found as an argument on the command line, but was not |
da769d56 ILT |
477 | // recognized as an ELF file. Try to read it as a script. Return |
478 | // true if the file was handled. This has to handle /usr/lib/libc.so | |
479 | // on a GNU/Linux system. *USED_NEXT_BLOCKER is set to indicate | |
480 | // whether the function took over NEXT_BLOCKER. | |
dbe717ef ILT |
481 | |
482 | bool | |
15f8229b | 483 | read_input_script(Workqueue*, Symbol_table*, Layout*, Dirsearch*, int, |
f1ed28fb | 484 | Input_objects*, Mapfile*, Input_group*, |
da769d56 ILT |
485 | const Input_argument*, Input_file*, |
486 | Task_token* next_blocker, bool* used_next_blocker); | |
dbe717ef | 487 | |
3c2fafa5 ILT |
488 | // FILE was found as an argument to --script (-T). |
489 | // Read it as a script, and execute its contents immediately. | |
490 | ||
491 | bool | |
c82fbeee | 492 | read_commandline_script(const char* filename, Command_line* cmdline); |
3c2fafa5 | 493 | |
09124467 ILT |
494 | // FILE was found as an argument to --version-script. Read it as a |
495 | // version script, and store its contents in | |
496 | // cmdline->script_options()->version_script_info(). | |
497 | ||
498 | bool | |
499 | read_version_script(const char* filename, Command_line* cmdline); | |
500 | ||
c82fbeee CS |
501 | // FILENAME was found as an argument to --dynamic-list. Read it as a |
502 | // version script (actually, a versym_node from a version script), and | |
503 | // store its contents in DYNAMIC_LIST. | |
504 | ||
505 | bool | |
506 | read_dynamic_list(const char* filename, Command_line* cmdline, | |
507 | Script_options* dynamic_list); | |
508 | ||
dbe717ef ILT |
509 | } // End namespace gold. |
510 | ||
511 | #endif // !defined(GOLD_SCRIPT_H) |