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.
38 class General_options;
50 // This class represents an expression in a linker script.
55 // These should only be created by child classes.
63 // Return the value of the expression.
65 eval(const Symbol_table*, const Layout*);
68 struct Expression_eval_info;
71 // Compute the value of the expression (implemented by child class).
72 // This is public rather than protected because it is called
73 // directly by children of Expression on other Expression objects.
75 value(const Expression_eval_info*) = 0;
79 Expression(const Expression&);
80 Expression& operator=(const Expression&);
83 // We can read a linker script in two different contexts: when
84 // initially parsing the command line, and when we find an input file
85 // which is actually a linker script. Also some of the data which can
86 // be set by a linker script can also be set via command line options
87 // like -e and --defsym. This means that we have a type of data which
88 // can be set both during command line option parsing and while
89 // reading input files. We store that data in an instance of this
90 // object. We will keep pointers to that instance in both the
91 // Command_line and Layout objects.
101 { return this->entry_.empty() ? NULL : this->entry_.c_str(); }
103 // Set the entry address.
105 set_entry(const char* entry, size_t length)
106 { this->entry_.assign(entry, length); }
108 // Add a symbol to be defined. These are for symbol definitions
109 // which appear outside of a SECTIONS clause.
111 add_symbol_assignment(const char* name, size_t length, Expression* value,
112 bool provided, bool hidden)
114 this->symbol_assignments_.push_back(Symbol_assignment(name, length, value,
118 // Define a symbol from the command line.
120 define_symbol(const char* definition);
122 // Add all symbol definitions to the symbol table.
124 add_symbols_to_table(Symbol_table*, const Target*);
126 // Finalize the symbol values.
128 finalize_symbols(Symbol_table*, const Layout*);
131 // We keep a list of symbol assignments.
132 struct Symbol_assignment
136 // Expression to assign to symbol.
138 // Whether the assignment should be provided (only set if there is
139 // an undefined reference to the symbol.
141 // Whether the assignment should be hidden.
143 // The entry in the symbol table.
146 Symbol_assignment(const char* namea, size_t lengtha, Expression* valuea,
147 bool providea, bool hiddena)
148 : name(namea, lengtha), value(valuea), provide(providea),
149 hidden(hiddena), sym(NULL)
153 typedef std::vector<Symbol_assignment> Symbol_assignments;
157 sized_finalize_symbols(Symbol_table*, const Layout*);
159 // The entry address. This will be empty if not set.
162 Symbol_assignments symbol_assignments_;
165 // FILE was found as an argument on the command line, but was not
166 // recognized as an ELF file. Try to read it as a script. We've
167 // already read BYTES of data into P. Return true if the file was
168 // handled. This has to handle /usr/lib/libc.so on a GNU/Linux
172 read_input_script(Workqueue*, const General_options&, Symbol_table*, Layout*,
173 Dirsearch*, Input_objects*, Input_group*,
174 const Input_argument*, Input_file*, const unsigned char* p,
175 off_t bytes, Task_token* this_blocker,
176 Task_token* next_blocker);
178 // FILE was found as an argument to --script (-T).
179 // Read it as a script, and execute its contents immediately.
182 read_commandline_script(const char* filename, Command_line*);
184 } // End namespace gold.
186 #endif // !defined(GOLD_SCRIPT_H)