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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 | ||
e5756efb ILT |
33 | #include <vector> |
34 | ||
09124467 ILT |
35 | struct Version_dependency_list; |
36 | struct Version_expression_list; | |
37 | struct Version_tree; | |
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; | |
3c2fafa5 | 46 | class Input_argument; |
dbe717ef ILT |
47 | class Input_objects; |
48 | class Input_group; | |
49 | class Input_file; | |
e5756efb | 50 | class Target; |
dbe717ef | 51 | class Task_token; |
3c2fafa5 | 52 | class Workqueue; |
dbe717ef | 53 | |
e5756efb ILT |
54 | // This class represents an expression in a linker script. |
55 | ||
56 | class Expression | |
57 | { | |
58 | protected: | |
59 | // These should only be created by child classes. | |
60 | Expression() | |
61 | { } | |
62 | ||
63 | public: | |
64 | virtual ~Expression() | |
65 | { } | |
66 | ||
67 | // Return the value of the expression. | |
68 | uint64_t | |
69 | eval(const Symbol_table*, const Layout*); | |
70 | ||
71 | protected: | |
72 | struct Expression_eval_info; | |
73 | ||
74 | public: | |
75 | // Compute the value of the expression (implemented by child class). | |
76 | // This is public rather than protected because it is called | |
77 | // directly by children of Expression on other Expression objects. | |
78 | virtual uint64_t | |
79 | value(const Expression_eval_info*) = 0; | |
80 | ||
81 | private: | |
82 | // May not be copied. | |
83 | Expression(const Expression&); | |
84 | Expression& operator=(const Expression&); | |
85 | }; | |
86 | ||
09124467 ILT |
87 | |
88 | // Version_script_info stores information parsed from the version | |
89 | // script, either provided by --version-script or as part of a linker | |
90 | // script. A single Version_script_info object per target is owned by | |
91 | // Script_options. | |
92 | ||
93 | class Version_script_info { | |
94 | public: | |
95 | ~Version_script_info(); | |
96 | ||
97 | // Return whether any version were defined in the version script. | |
98 | bool | |
99 | empty() const | |
100 | { return this->version_trees_.empty(); } | |
101 | ||
102 | // Return the version associated with the given symbol name. | |
103 | // Strings are allocated out of the stringpool given in the | |
104 | // constructor. Strings are allocated out of the stringpool given | |
105 | // in the constructor. | |
106 | const std::string& | |
107 | get_symbol_version(const char* symbol) const | |
108 | { return get_symbol_version_helper(symbol, true); } | |
109 | ||
110 | // Return whether this symbol matches the local: section of a | |
111 | // version script (it doesn't matter which). This test is only | |
112 | // valid if get_symbol_version() returns the empty string, as we | |
113 | // don't test that here. | |
114 | bool | |
115 | symbol_is_local(const char* symbol) const | |
116 | { return !get_symbol_version_helper(symbol, false).empty(); } | |
117 | ||
118 | // Return the names of versions defined in the version script. | |
119 | // Strings are allocated out of the stringpool given in the | |
120 | // constructor. | |
121 | std::vector<std::string> | |
122 | get_versions() const; | |
123 | ||
124 | // Return the list of dependencies for this version. | |
125 | std::vector<std::string> | |
126 | get_dependencies(const char* version) const; | |
127 | ||
128 | // The following functions should only be used by the bison helper | |
129 | // functions. They allocate new structs whose memory belongs to | |
130 | // Version_script_info. The bison functions copy the information | |
131 | // from the version script into these structs. | |
132 | struct Version_dependency_list* | |
133 | allocate_dependency_list(); | |
134 | ||
135 | struct Version_expression_list* | |
136 | allocate_expression_list(); | |
137 | ||
138 | struct Version_tree* | |
139 | allocate_version_tree(); | |
140 | ||
141 | private: | |
142 | const std::string& get_symbol_version_helper(const char* symbol, | |
143 | bool check_global) const; | |
144 | ||
145 | std::vector<struct Version_dependency_list*> dependency_lists_; | |
146 | std::vector<struct Version_expression_list*> expression_lists_; | |
147 | std::vector<struct Version_tree*> version_trees_; | |
148 | }; | |
149 | ||
e5756efb ILT |
150 | // We can read a linker script in two different contexts: when |
151 | // initially parsing the command line, and when we find an input file | |
152 | // which is actually a linker script. Also some of the data which can | |
153 | // be set by a linker script can also be set via command line options | |
154 | // like -e and --defsym. This means that we have a type of data which | |
155 | // can be set both during command line option parsing and while | |
156 | // reading input files. We store that data in an instance of this | |
157 | // object. We will keep pointers to that instance in both the | |
158 | // Command_line and Layout objects. | |
159 | ||
160 | class Script_options | |
161 | { | |
162 | public: | |
163 | Script_options(); | |
164 | ||
165 | // The entry address. | |
166 | const char* | |
167 | entry() const | |
168 | { return this->entry_.empty() ? NULL : this->entry_.c_str(); } | |
169 | ||
170 | // Set the entry address. | |
171 | void | |
172 | set_entry(const char* entry, size_t length) | |
173 | { this->entry_.assign(entry, length); } | |
174 | ||
175 | // Add a symbol to be defined. These are for symbol definitions | |
176 | // which appear outside of a SECTIONS clause. | |
177 | void | |
178 | add_symbol_assignment(const char* name, size_t length, Expression* value, | |
179 | bool provided, bool hidden) | |
180 | { | |
181 | this->symbol_assignments_.push_back(Symbol_assignment(name, length, value, | |
182 | provided, hidden)); | |
183 | } | |
184 | ||
185 | // Define a symbol from the command line. | |
186 | bool | |
187 | define_symbol(const char* definition); | |
188 | ||
189 | // Add all symbol definitions to the symbol table. | |
190 | void | |
191 | add_symbols_to_table(Symbol_table*, const Target*); | |
192 | ||
193 | // Finalize the symbol values. | |
194 | void | |
195 | finalize_symbols(Symbol_table*, const Layout*); | |
196 | ||
09124467 ILT |
197 | // Version information parsed from a version script. Everything |
198 | // else has a pointer to this object. | |
199 | Version_script_info* | |
200 | version_script_info() | |
201 | { return &version_script_info_; } | |
202 | ||
e5756efb ILT |
203 | private: |
204 | // We keep a list of symbol assignments. | |
205 | struct Symbol_assignment | |
206 | { | |
207 | // Symbol name. | |
208 | std::string name; | |
209 | // Expression to assign to symbol. | |
210 | Expression* value; | |
211 | // Whether the assignment should be provided (only set if there is | |
212 | // an undefined reference to the symbol. | |
213 | bool provide; | |
214 | // Whether the assignment should be hidden. | |
215 | bool hidden; | |
216 | // The entry in the symbol table. | |
217 | Symbol* sym; | |
218 | ||
219 | Symbol_assignment(const char* namea, size_t lengtha, Expression* valuea, | |
220 | bool providea, bool hiddena) | |
221 | : name(namea, lengtha), value(valuea), provide(providea), | |
222 | hidden(hiddena), sym(NULL) | |
223 | { } | |
224 | }; | |
225 | ||
226 | typedef std::vector<Symbol_assignment> Symbol_assignments; | |
227 | ||
228 | template<int size> | |
229 | void | |
230 | sized_finalize_symbols(Symbol_table*, const Layout*); | |
231 | ||
232 | // The entry address. This will be empty if not set. | |
233 | std::string entry_; | |
234 | // Symbols to set. | |
235 | Symbol_assignments symbol_assignments_; | |
09124467 ILT |
236 | // Version information parsed from a version script. |
237 | Version_script_info version_script_info_; | |
e5756efb ILT |
238 | }; |
239 | ||
dbe717ef ILT |
240 | // FILE was found as an argument on the command line, but was not |
241 | // recognized as an ELF file. Try to read it as a script. We've | |
242 | // already read BYTES of data into P. Return true if the file was | |
243 | // handled. This has to handle /usr/lib/libc.so on a GNU/Linux | |
244 | // system. | |
245 | ||
246 | bool | |
247 | read_input_script(Workqueue*, const General_options&, Symbol_table*, Layout*, | |
17a1d0a9 | 248 | Dirsearch*, Input_objects*, Input_group*, |
dbe717ef ILT |
249 | const Input_argument*, Input_file*, const unsigned char* p, |
250 | off_t bytes, Task_token* this_blocker, | |
251 | Task_token* next_blocker); | |
252 | ||
3c2fafa5 ILT |
253 | // FILE was found as an argument to --script (-T). |
254 | // Read it as a script, and execute its contents immediately. | |
255 | ||
256 | bool | |
257 | read_commandline_script(const char* filename, Command_line*); | |
258 | ||
09124467 ILT |
259 | // FILE was found as an argument to --version-script. Read it as a |
260 | // version script, and store its contents in | |
261 | // cmdline->script_options()->version_script_info(). | |
262 | ||
263 | bool | |
264 | read_version_script(const char* filename, Command_line* cmdline); | |
265 | ||
266 | ||
dbe717ef ILT |
267 | } // End namespace gold. |
268 | ||
269 | #endif // !defined(GOLD_SCRIPT_H) |