1 // script.h -- handle linker scripts for gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
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.
36 #include "script-sections.h"
41 class General_options
;
52 struct Version_dependency_list
;
53 struct Version_expression_list
;
56 // This class represents an expression in a linker script.
61 // These should only be created by child classes.
69 // Return the value of the expression.
71 eval(const Symbol_table
*, const Layout
*);
73 // Print the expression to the FILE. This is for debugging.
75 print(FILE*) const = 0;
78 struct Expression_eval_info
;
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.
85 value(const Expression_eval_info
*) = 0;
89 Expression(const Expression
&);
90 Expression
& operator=(const Expression
&);
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
99 class Version_script_info
102 ~Version_script_info();
104 // Return whether any version were defined in the version script.
107 { return this->version_trees_
.empty(); }
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.
114 get_symbol_version(const char* symbol
) const
115 { return get_symbol_version_helper(symbol
, true); }
117 // Return whether this symbol matches the local: section of a
118 // version script (it doesn't matter which). This test is only
119 // valid if get_symbol_version() returns the empty string, as we
120 // don't test that here.
122 symbol_is_local(const char* symbol
) const
123 { return !get_symbol_version_helper(symbol
, false).empty(); }
125 // Return the names of versions defined in the version script.
126 // Strings are allocated out of the stringpool given in the
128 std::vector
<std::string
>
129 get_versions() const;
131 // Return the list of dependencies for this version.
132 std::vector
<std::string
>
133 get_dependencies(const char* version
) const;
135 // The following functions should only be used by the bison helper
136 // functions. They allocate new structs whose memory belongs to
137 // Version_script_info. The bison functions copy the information
138 // from the version script into these structs.
139 struct Version_dependency_list
*
140 allocate_dependency_list();
142 struct Version_expression_list
*
143 allocate_expression_list();
146 allocate_version_tree();
148 // Print contents to the FILE. This is for debugging.
154 print_expression_list(FILE* f
, const Version_expression_list
*) const;
156 const std::string
& get_symbol_version_helper(const char* symbol
,
157 bool check_global
) const;
159 std::vector
<struct Version_dependency_list
*> dependency_lists_
;
160 std::vector
<struct Version_expression_list
*> expression_lists_
;
161 std::vector
<struct Version_tree
*> version_trees_
;
164 // This class manages assignments to symbols. These can appear in
165 // three different locations in scripts: outside of a SECTIONS clause,
166 // within a SECTIONS clause, and within an output section definition
167 // within a SECTIONS clause. This can also appear on the command line
168 // via the --defsym command line option.
170 class Symbol_assignment
173 Symbol_assignment(const char* name
, size_t namelen
, Expression
* val
,
174 bool provide
, bool hidden
)
175 : name_(name
, namelen
), val_(val
), provide_(provide
), hidden_(hidden
),
179 // Add the symbol to the symbol table.
181 add_to_table(Symbol_table
*, const Target
*);
183 // Finalize the symbol value.
184 void finalize(Symbol_table
*, const Layout
*);
186 // Print the assignment to the FILE. This is for debugging.
191 // Sized version of finalize.
194 sized_finalize(Symbol_table
*, const Layout
*);
198 // Expression to assign to symbol.
200 // Whether the assignment should be provided (only set if there is
201 // an undefined reference to the symbol.
203 // Whether the assignment should be hidden.
205 // The entry in the symbol table.
209 // This class manages assertions in linker scripts. These can appear
210 // in all the places where a Symbol_assignment can appear.
212 class Script_assertion
215 Script_assertion(Expression
* check
, const char* message
,
217 : check_(check
), message_(message
, messagelen
)
220 // Check the assertion.
222 check(const Symbol_table
*, const Layout
*);
224 // Print the assertion to the FILE. This is for debugging.
229 // The expression to check.
231 // The message to issue if the expression fails.
232 std::string message_
;
235 // We can read a linker script in two different contexts: when
236 // initially parsing the command line, and when we find an input file
237 // which is actually a linker script. Also some of the data which can
238 // be set by a linker script can also be set via command line options
239 // like -e and --defsym. This means that we have a type of data which
240 // can be set both during command line option parsing and while
241 // reading input files. We store that data in an instance of this
242 // object. We will keep pointers to that instance in both the
243 // Command_line and Layout objects.
250 // The entry address.
253 { return this->entry_
.empty() ? NULL
: this->entry_
.c_str(); }
255 // Set the entry address.
257 set_entry(const char* entry
, size_t length
)
258 { this->entry_
.assign(entry
, length
); }
260 // Add a symbol to be defined.
262 add_symbol_assignment(const char* name
, size_t length
, Expression
* value
,
263 bool provide
, bool hidden
);
267 add_assertion(Expression
* check
, const char* message
, size_t messagelen
);
269 // Define a symbol from the command line.
271 define_symbol(const char* definition
);
273 // Add all symbol definitions to the symbol table.
275 add_symbols_to_table(Symbol_table
*, const Target
*);
277 // Finalize the symbol values.
279 finalize_symbols(Symbol_table
*, const Layout
*);
281 // Version information parsed from a version script. Everything
282 // else has a pointer to this object.
284 version_script_info()
285 { return &this->version_script_info_
; }
287 // A SECTIONS clause parsed from a linker script. Everything else
288 // has a pointer to this object.
291 { return &this->script_sections_
; }
293 // Print the script to the FILE. This is for debugging.
298 // We keep a list of symbol assignments which occur outside of a
300 typedef std::vector
<Symbol_assignment
*> Symbol_assignments
;
302 // We keep a list of all assertions whcih occur outside of a
304 typedef std::vector
<Script_assertion
*> Assertions
;
306 // The entry address. This will be empty if not set.
309 Symbol_assignments symbol_assignments_
;
310 // Assertions to check.
311 Assertions assertions_
;
312 // Version information parsed from a version script.
313 Version_script_info version_script_info_
;
314 // Information from any SECTIONS clauses.
315 Script_sections script_sections_
;
318 // FILE was found as an argument on the command line, but was not
319 // recognized as an ELF file. Try to read it as a script. We've
320 // already read BYTES of data into P. Return true if the file was
321 // handled. This has to handle /usr/lib/libc.so on a GNU/Linux
325 read_input_script(Workqueue
*, const General_options
&, Symbol_table
*, Layout
*,
326 Dirsearch
*, Input_objects
*, Input_group
*,
327 const Input_argument
*, Input_file
*, const unsigned char* p
,
328 off_t bytes
, Task_token
* this_blocker
,
329 Task_token
* next_blocker
);
331 // FILE was found as an argument to --script (-T).
332 // Read it as a script, and execute its contents immediately.
335 read_commandline_script(const char* filename
, Command_line
*);
337 // FILE was found as an argument to --version-script. Read it as a
338 // version script, and store its contents in
339 // cmdline->script_options()->version_script_info().
342 read_version_script(const char* filename
, Command_line
* cmdline
);
345 } // End namespace gold.
347 #endif // !defined(GOLD_SCRIPT_H)