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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> |
e5756efb ILT |
34 | #include <vector> |
35 | ||
494e05f4 | 36 | #include "script-sections.h" |
09124467 | 37 | |
dbe717ef ILT |
38 | namespace gold |
39 | { | |
40 | ||
41 | class General_options; | |
3c2fafa5 | 42 | class Command_line; |
dbe717ef ILT |
43 | class Symbol_table; |
44 | class Layout; | |
3c2fafa5 | 45 | class Input_argument; |
dbe717ef ILT |
46 | class Input_objects; |
47 | class Input_group; | |
48 | class Input_file; | |
e5756efb | 49 | class Target; |
dbe717ef | 50 | class Task_token; |
3c2fafa5 | 51 | class Workqueue; |
494e05f4 ILT |
52 | struct Version_dependency_list; |
53 | struct Version_expression_list; | |
54 | struct Version_tree; | |
dbe717ef | 55 | |
e5756efb ILT |
56 | // This class represents an expression in a linker script. |
57 | ||
58 | class Expression | |
59 | { | |
60 | protected: | |
61 | // These should only be created by child classes. | |
62 | Expression() | |
63 | { } | |
64 | ||
65 | public: | |
66 | virtual ~Expression() | |
67 | { } | |
68 | ||
69 | // Return the value of the expression. | |
70 | uint64_t | |
71 | eval(const Symbol_table*, const Layout*); | |
72 | ||
494e05f4 ILT |
73 | // Print the expression to the FILE. This is for debugging. |
74 | virtual void | |
75 | print(FILE*) const = 0; | |
76 | ||
e5756efb ILT |
77 | protected: |
78 | struct Expression_eval_info; | |
79 | ||
80 | public: | |
81 | // Compute the value of the expression (implemented by child class). | |
82 | // This is public rather than protected because it is called | |
83 | // directly by children of Expression on other Expression objects. | |
84 | virtual uint64_t | |
85 | value(const Expression_eval_info*) = 0; | |
86 | ||
87 | private: | |
88 | // May not be copied. | |
89 | Expression(const Expression&); | |
90 | Expression& operator=(const Expression&); | |
91 | }; | |
92 | ||
09124467 ILT |
93 | |
94 | // Version_script_info stores information parsed from the version | |
95 | // script, either provided by --version-script or as part of a linker | |
96 | // script. A single Version_script_info object per target is owned by | |
97 | // Script_options. | |
98 | ||
494e05f4 ILT |
99 | class Version_script_info |
100 | { | |
09124467 ILT |
101 | public: |
102 | ~Version_script_info(); | |
103 | ||
104 | // Return whether any version were defined in the version script. | |
105 | bool | |
106 | empty() const | |
107 | { return this->version_trees_.empty(); } | |
108 | ||
109 | // Return the version associated with the given symbol name. | |
110 | // Strings are allocated out of the stringpool given in the | |
111 | // constructor. Strings are allocated out of the stringpool given | |
112 | // in the constructor. | |
113 | const std::string& | |
114 | get_symbol_version(const char* symbol) const | |
115 | { return get_symbol_version_helper(symbol, true); } | |
116 | ||
117 | // Return whether this symbol matches the local: section of a | |
1dd940af | 118 | // version script (it doesn't matter which). |
09124467 ILT |
119 | bool |
120 | symbol_is_local(const char* symbol) const | |
1dd940af ILT |
121 | { |
122 | return (get_symbol_version(symbol).empty() | |
123 | && !get_symbol_version_helper(symbol, false).empty()); | |
124 | } | |
09124467 ILT |
125 | |
126 | // Return the names of versions defined in the version script. | |
127 | // Strings are allocated out of the stringpool given in the | |
128 | // constructor. | |
129 | std::vector<std::string> | |
130 | get_versions() const; | |
131 | ||
132 | // Return the list of dependencies for this version. | |
133 | std::vector<std::string> | |
134 | get_dependencies(const char* version) const; | |
135 | ||
136 | // The following functions should only be used by the bison helper | |
137 | // functions. They allocate new structs whose memory belongs to | |
138 | // Version_script_info. The bison functions copy the information | |
139 | // from the version script into these structs. | |
140 | struct Version_dependency_list* | |
141 | allocate_dependency_list(); | |
142 | ||
143 | struct Version_expression_list* | |
144 | allocate_expression_list(); | |
145 | ||
146 | struct Version_tree* | |
147 | allocate_version_tree(); | |
148 | ||
494e05f4 ILT |
149 | // Print contents to the FILE. This is for debugging. |
150 | void | |
151 | print(FILE*) const; | |
152 | ||
09124467 | 153 | private: |
494e05f4 ILT |
154 | void |
155 | print_expression_list(FILE* f, const Version_expression_list*) const; | |
156 | ||
09124467 ILT |
157 | const std::string& get_symbol_version_helper(const char* symbol, |
158 | bool check_global) const; | |
159 | ||
160 | std::vector<struct Version_dependency_list*> dependency_lists_; | |
161 | std::vector<struct Version_expression_list*> expression_lists_; | |
162 | std::vector<struct Version_tree*> version_trees_; | |
163 | }; | |
164 | ||
494e05f4 ILT |
165 | // This class manages assignments to symbols. These can appear in |
166 | // three different locations in scripts: outside of a SECTIONS clause, | |
167 | // within a SECTIONS clause, and within an output section definition | |
168 | // within a SECTIONS clause. This can also appear on the command line | |
169 | // via the --defsym command line option. | |
170 | ||
171 | class Symbol_assignment | |
172 | { | |
173 | public: | |
174 | Symbol_assignment(const char* name, size_t namelen, Expression* val, | |
175 | bool provide, bool hidden) | |
176 | : name_(name, namelen), val_(val), provide_(provide), hidden_(hidden), | |
177 | sym_(NULL) | |
178 | { } | |
179 | ||
180 | // Add the symbol to the symbol table. | |
181 | void | |
182 | add_to_table(Symbol_table*, const Target*); | |
183 | ||
184 | // Finalize the symbol value. | |
185 | void finalize(Symbol_table*, const Layout*); | |
186 | ||
187 | // Print the assignment to the FILE. This is for debugging. | |
188 | void | |
189 | print(FILE*) const; | |
190 | ||
191 | private: | |
192 | // Sized version of finalize. | |
193 | template<int size> | |
194 | void | |
195 | sized_finalize(Symbol_table*, const Layout*); | |
196 | ||
197 | // Symbol name. | |
198 | std::string name_; | |
199 | // Expression to assign to symbol. | |
200 | Expression* val_; | |
201 | // Whether the assignment should be provided (only set if there is | |
202 | // an undefined reference to the symbol. | |
203 | bool provide_; | |
204 | // Whether the assignment should be hidden. | |
205 | bool hidden_; | |
206 | // The entry in the symbol table. | |
207 | Symbol* sym_; | |
208 | }; | |
209 | ||
210 | // This class manages assertions in linker scripts. These can appear | |
211 | // in all the places where a Symbol_assignment can appear. | |
212 | ||
213 | class Script_assertion | |
214 | { | |
215 | public: | |
216 | Script_assertion(Expression* check, const char* message, | |
217 | size_t messagelen) | |
218 | : check_(check), message_(message, messagelen) | |
219 | { } | |
220 | ||
221 | // Check the assertion. | |
222 | void | |
223 | check(const Symbol_table*, const Layout*); | |
224 | ||
225 | // Print the assertion to the FILE. This is for debugging. | |
226 | void | |
227 | print(FILE*) const; | |
228 | ||
229 | private: | |
230 | // The expression to check. | |
231 | Expression* check_; | |
232 | // The message to issue if the expression fails. | |
233 | std::string message_; | |
234 | }; | |
235 | ||
e5756efb ILT |
236 | // We can read a linker script in two different contexts: when |
237 | // initially parsing the command line, and when we find an input file | |
238 | // which is actually a linker script. Also some of the data which can | |
239 | // be set by a linker script can also be set via command line options | |
240 | // like -e and --defsym. This means that we have a type of data which | |
241 | // can be set both during command line option parsing and while | |
242 | // reading input files. We store that data in an instance of this | |
243 | // object. We will keep pointers to that instance in both the | |
244 | // Command_line and Layout objects. | |
245 | ||
246 | class Script_options | |
247 | { | |
248 | public: | |
249 | Script_options(); | |
250 | ||
251 | // The entry address. | |
252 | const char* | |
253 | entry() const | |
254 | { return this->entry_.empty() ? NULL : this->entry_.c_str(); } | |
255 | ||
256 | // Set the entry address. | |
257 | void | |
258 | set_entry(const char* entry, size_t length) | |
259 | { this->entry_.assign(entry, length); } | |
260 | ||
494e05f4 | 261 | // Add a symbol to be defined. |
e5756efb ILT |
262 | void |
263 | add_symbol_assignment(const char* name, size_t length, Expression* value, | |
494e05f4 ILT |
264 | bool provide, bool hidden); |
265 | ||
266 | // Add an assertion. | |
267 | void | |
268 | add_assertion(Expression* check, const char* message, size_t messagelen); | |
e5756efb ILT |
269 | |
270 | // Define a symbol from the command line. | |
271 | bool | |
272 | define_symbol(const char* definition); | |
273 | ||
274 | // Add all symbol definitions to the symbol table. | |
275 | void | |
276 | add_symbols_to_table(Symbol_table*, const Target*); | |
277 | ||
278 | // Finalize the symbol values. | |
279 | void | |
280 | finalize_symbols(Symbol_table*, const Layout*); | |
281 | ||
09124467 ILT |
282 | // Version information parsed from a version script. Everything |
283 | // else has a pointer to this object. | |
284 | Version_script_info* | |
285 | version_script_info() | |
494e05f4 | 286 | { return &this->version_script_info_; } |
09124467 | 287 | |
494e05f4 ILT |
288 | // A SECTIONS clause parsed from a linker script. Everything else |
289 | // has a pointer to this object. | |
290 | Script_sections* | |
291 | script_sections() | |
292 | { return &this->script_sections_; } | |
e5756efb | 293 | |
494e05f4 | 294 | // Print the script to the FILE. This is for debugging. |
e5756efb | 295 | void |
494e05f4 ILT |
296 | print(FILE*) const; |
297 | ||
298 | private: | |
299 | // We keep a list of symbol assignments which occur outside of a | |
300 | // SECTIONS clause. | |
301 | typedef std::vector<Symbol_assignment*> Symbol_assignments; | |
302 | ||
303 | // We keep a list of all assertions whcih occur outside of a | |
304 | // SECTIONS clause. | |
305 | typedef std::vector<Script_assertion*> Assertions; | |
e5756efb ILT |
306 | |
307 | // The entry address. This will be empty if not set. | |
308 | std::string entry_; | |
309 | // Symbols to set. | |
310 | Symbol_assignments symbol_assignments_; | |
494e05f4 ILT |
311 | // Assertions to check. |
312 | Assertions assertions_; | |
09124467 ILT |
313 | // Version information parsed from a version script. |
314 | Version_script_info version_script_info_; | |
494e05f4 ILT |
315 | // Information from any SECTIONS clauses. |
316 | Script_sections script_sections_; | |
e5756efb ILT |
317 | }; |
318 | ||
dbe717ef ILT |
319 | // FILE was found as an argument on the command line, but was not |
320 | // recognized as an ELF file. Try to read it as a script. We've | |
321 | // already read BYTES of data into P. Return true if the file was | |
322 | // handled. This has to handle /usr/lib/libc.so on a GNU/Linux | |
323 | // system. | |
324 | ||
325 | bool | |
326 | read_input_script(Workqueue*, const General_options&, Symbol_table*, Layout*, | |
17a1d0a9 | 327 | Dirsearch*, Input_objects*, Input_group*, |
dbe717ef ILT |
328 | const Input_argument*, Input_file*, const unsigned char* p, |
329 | off_t bytes, Task_token* this_blocker, | |
330 | Task_token* next_blocker); | |
331 | ||
3c2fafa5 ILT |
332 | // FILE was found as an argument to --script (-T). |
333 | // Read it as a script, and execute its contents immediately. | |
334 | ||
335 | bool | |
336 | read_commandline_script(const char* filename, Command_line*); | |
337 | ||
09124467 ILT |
338 | // FILE was found as an argument to --version-script. Read it as a |
339 | // version script, and store its contents in | |
340 | // cmdline->script_options()->version_script_info(). | |
341 | ||
342 | bool | |
343 | read_version_script(const char* filename, Command_line* cmdline); | |
344 | ||
345 | ||
dbe717ef ILT |
346 | } // End namespace gold. |
347 | ||
348 | #endif // !defined(GOLD_SCRIPT_H) |