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bae7f79e ILT |
1 | // object.h -- support for an object file for linking in gold -*- C++ -*- |
2 | ||
3 | #ifndef GOLD_OBJECT_H | |
4 | #define GOLD_OBJECT_H | |
5 | ||
14bfc3f5 | 6 | #include <cassert> |
a2fb1b05 | 7 | #include <vector> |
14bfc3f5 | 8 | |
bae7f79e | 9 | #include "elfcpp.h" |
bae7f79e | 10 | #include "fileread.h" |
14bfc3f5 ILT |
11 | #include "target.h" |
12 | #include "symtab.h" | |
bae7f79e ILT |
13 | |
14 | namespace gold | |
15 | { | |
16 | ||
a2fb1b05 ILT |
17 | class Output_section; |
18 | class Layout; | |
19 | ||
bae7f79e ILT |
20 | // Data to pass from read_symbols() to add_symbols(). |
21 | ||
22 | struct Read_symbols_data | |
23 | { | |
24 | // Symbol data. | |
25 | File_view* symbols; | |
26 | // Size of symbol data in bytes. | |
27 | off_t symbols_size; | |
54dc6425 ILT |
28 | // Index of first global symbol. |
29 | unsigned int first_global; | |
bae7f79e ILT |
30 | // Symbol names. |
31 | File_view* symbol_names; | |
32 | // Size of symbol name data in bytes. | |
33 | off_t symbol_names_size; | |
34 | }; | |
35 | ||
36 | // Object is an interface which represents either a 32-bit or a 64-bit | |
14bfc3f5 ILT |
37 | // input object. This can be a regular object file (ET_REL) or a |
38 | // shared object (ET_DYN). The actual instantiations are | |
39 | // Sized_object<32> and Sized_object<64> | |
bae7f79e ILT |
40 | |
41 | class Object | |
42 | { | |
43 | public: | |
44 | // NAME is the name of the object as we would report it to the user | |
45 | // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is | |
46 | // used to read the file. OFFSET is the offset within the input | |
47 | // file--0 for a .o or .so file, something else for a .a file. | |
14bfc3f5 ILT |
48 | Object(const std::string& name, Input_file* input_file, bool is_dynamic, |
49 | off_t offset = 0) | |
50 | : name_(name), input_file_(input_file), offset_(offset), | |
a2fb1b05 ILT |
51 | shnum_(0), is_dynamic_(is_dynamic), target_(NULL), |
52 | map_to_output_() | |
bae7f79e ILT |
53 | { } |
54 | ||
55 | virtual ~Object() | |
56 | { } | |
57 | ||
14bfc3f5 | 58 | // Return the name of the object as we would report it to the tuser. |
bae7f79e ILT |
59 | const std::string& |
60 | name() const | |
61 | { return this->name_; } | |
62 | ||
14bfc3f5 ILT |
63 | // Return whether this is a dynamic object. |
64 | bool | |
65 | is_dynamic() const | |
66 | { return this->is_dynamic_; } | |
67 | ||
14bfc3f5 ILT |
68 | // Return the target structure associated with this object. |
69 | Target* | |
a2fb1b05 | 70 | target() const |
14bfc3f5 ILT |
71 | { return this->target_; } |
72 | ||
a2fb1b05 ILT |
73 | // Lock the underlying file. |
74 | void | |
75 | lock() | |
76 | { this->input_file_->file().lock(); } | |
77 | ||
78 | // Unlock the underlying file. | |
79 | void | |
80 | unlock() | |
81 | { this->input_file_->file().unlock(); } | |
82 | ||
83 | // Return whether the underlying file is locked. | |
84 | bool | |
85 | is_locked() const | |
86 | { return this->input_file_->file().is_locked(); } | |
87 | ||
d288e464 | 88 | #ifdef HAVE_MEMBER_TEMPLATE_SPECIFICATIONS |
14bfc3f5 ILT |
89 | // Return the sized target structure associated with this object. |
90 | // This is like the target method but it returns a pointer of | |
91 | // appropriate checked type. | |
92 | template<int size, bool big_endian> | |
93 | Sized_target<size, big_endian>* | |
94 | sized_target(); | |
d288e464 | 95 | #endif |
bae7f79e | 96 | |
a2fb1b05 ILT |
97 | // Read the symbol and relocation information. |
98 | Read_symbols_data | |
99 | read_symbols() | |
100 | { return this->do_read_symbols(); } | |
101 | ||
102 | // Add symbol information to the global symbol table. | |
103 | void | |
104 | add_symbols(Symbol_table* symtab, Read_symbols_data rd) | |
105 | { this->do_add_symbols(symtab, rd); } | |
106 | ||
107 | // Pass sections which should be included in the link to the Layout | |
108 | // object, and record where the sections go in the output file. | |
109 | void | |
110 | layout(Layout* lay) | |
111 | { this->do_layout(lay); } | |
112 | ||
bae7f79e | 113 | protected: |
a2fb1b05 ILT |
114 | // What we need to know to map an input section to an output |
115 | // section. We keep an array of these, one for each input section, | |
116 | // indexed by the input section number. | |
117 | struct Map_to_output | |
118 | { | |
119 | // The output section. This is NULL if the input section is to be | |
120 | // discarded. | |
121 | Output_section* output_section; | |
122 | // The offset within the output section. | |
123 | off_t offset; | |
124 | }; | |
125 | ||
bae7f79e ILT |
126 | // Read the symbols--implemented by child class. |
127 | virtual Read_symbols_data | |
128 | do_read_symbols() = 0; | |
129 | ||
130 | // Add symbol information to the global symbol table--implemented by | |
131 | // child class. | |
132 | virtual void | |
14bfc3f5 | 133 | do_add_symbols(Symbol_table*, Read_symbols_data) = 0; |
bae7f79e | 134 | |
a2fb1b05 ILT |
135 | // Lay out sections--implemented by child class. |
136 | virtual void | |
137 | do_layout(Layout*) = 0; | |
138 | ||
bae7f79e ILT |
139 | // Get the file. |
140 | Input_file* | |
141 | input_file() const | |
142 | { return this->input_file_; } | |
143 | ||
144 | // Get the offset into the file. | |
145 | off_t | |
146 | offset() const | |
147 | { return this->offset_; } | |
148 | ||
149 | // Get a view into the underlying file. | |
150 | const unsigned char* | |
151 | get_view(off_t start, off_t size); | |
152 | ||
a2fb1b05 ILT |
153 | // Get the number of sections. |
154 | unsigned int | |
155 | shnum(void) const | |
156 | { return this->shnum_; } | |
157 | ||
158 | // Set the number of sections. | |
159 | void | |
160 | set_shnum(int shnum) | |
161 | { this->shnum_ = shnum; } | |
162 | ||
14bfc3f5 ILT |
163 | // Set the target. |
164 | void | |
165 | set_target(Target* target) | |
166 | { this->target_ = target; } | |
167 | ||
bae7f79e ILT |
168 | // Read data from the underlying file. |
169 | void | |
170 | read(off_t start, off_t size, void* p); | |
171 | ||
172 | // Get a lasting view into the underlying file. | |
173 | File_view* | |
174 | get_lasting_view(off_t start, off_t size); | |
175 | ||
a2fb1b05 ILT |
176 | // Return the vector mapping input sections to output sections. |
177 | std::vector<Map_to_output>& | |
178 | map_to_output() | |
179 | { return this->map_to_output_; } | |
180 | ||
bae7f79e ILT |
181 | private: |
182 | // This class may not be copied. | |
183 | Object(const Object&); | |
184 | Object& operator=(const Object&); | |
185 | ||
186 | // Name of object as printed to use. | |
187 | std::string name_; | |
188 | // For reading the file. | |
189 | Input_file* input_file_; | |
190 | // Offset within the file--0 for an object file, non-0 for an | |
191 | // archive. | |
192 | off_t offset_; | |
a2fb1b05 ILT |
193 | // Number of input sections. |
194 | unsigned int shnum_; | |
14bfc3f5 ILT |
195 | // Whether this is a dynamic object. |
196 | bool is_dynamic_; | |
197 | // Target functions--may be NULL if the target is not known. | |
198 | Target* target_; | |
a2fb1b05 ILT |
199 | // Mapping from input sections to output section. |
200 | std::vector<Map_to_output> map_to_output_; | |
bae7f79e ILT |
201 | }; |
202 | ||
d288e464 ILT |
203 | #ifdef HAVE_MEMBER_TEMPLATE_SPECIFICATIONS |
204 | ||
14bfc3f5 ILT |
205 | // Implement sized_target inline for efficiency. This approach breaks |
206 | // static type checking, but is made safe using asserts. | |
207 | ||
208 | template<int size, bool big_endian> | |
209 | inline Sized_target<size, big_endian>* | |
210 | Object::sized_target() | |
211 | { | |
212 | assert(this->target_->get_size() == size); | |
213 | assert(this->target_->is_big_endian() ? big_endian : !big_endian); | |
214 | return static_cast<Sized_target<size, big_endian>*>(this->target_); | |
215 | } | |
216 | ||
d288e464 ILT |
217 | #endif |
218 | ||
14bfc3f5 | 219 | // A regular object file. This is size and endian specific. |
bae7f79e ILT |
220 | |
221 | template<int size, bool big_endian> | |
222 | class Sized_object : public Object | |
223 | { | |
224 | public: | |
225 | Sized_object(const std::string& name, Input_file* input_file, off_t offset, | |
226 | const typename elfcpp::Ehdr<size, big_endian>&); | |
227 | ||
228 | ~Sized_object(); | |
229 | ||
a2fb1b05 | 230 | // Set up the object file based on the ELF header. |
bae7f79e ILT |
231 | void |
232 | setup(const typename elfcpp::Ehdr<size, big_endian>&); | |
233 | ||
a2fb1b05 | 234 | // Read the symbols. |
bae7f79e ILT |
235 | Read_symbols_data |
236 | do_read_symbols(); | |
237 | ||
a2fb1b05 | 238 | // Add the symbols to the symbol table. |
bae7f79e | 239 | void |
14bfc3f5 ILT |
240 | do_add_symbols(Symbol_table*, Read_symbols_data); |
241 | ||
a2fb1b05 ILT |
242 | // Lay out the input sections. |
243 | void | |
244 | do_layout(Layout*); | |
245 | ||
246 | // Return the appropriate Sized_target structure. | |
14bfc3f5 ILT |
247 | Sized_target<size, big_endian>* |
248 | sized_target() | |
274e99f9 ILT |
249 | { |
250 | #ifdef HAVE_MEMBER_TEMPLATE_SPECIFICATIONS | |
251 | return this->Object::sized_target<size, big_endian>(); | |
252 | #else | |
253 | return static_cast<Sized_target<size, big_endian>*>(this->target()); | |
254 | #endif | |
255 | } | |
bae7f79e ILT |
256 | |
257 | private: | |
258 | // This object may not be copied. | |
259 | Sized_object(const Sized_object&); | |
260 | Sized_object& operator=(const Sized_object&); | |
261 | ||
a2fb1b05 ILT |
262 | // For convenience. |
263 | typedef Sized_object<size, big_endian> This; | |
264 | static const int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size; | |
265 | static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size; | |
266 | static const int sym_size = elfcpp::Elf_sizes<size>::sym_size; | |
267 | ||
268 | // Whether to include a section group in the link. | |
269 | bool | |
270 | include_section_group(Layout*, unsigned int, | |
271 | const elfcpp::Shdr<size, big_endian>&, | |
272 | std::vector<bool>*); | |
273 | ||
274 | // Whether to include a linkonce section in the link. | |
275 | bool | |
276 | include_linkonce_section(Layout*, const char*, | |
277 | const elfcpp::Shdr<size, big_endian>&); | |
278 | ||
bae7f79e ILT |
279 | // ELF file header e_flags field. |
280 | unsigned int flags_; | |
bae7f79e ILT |
281 | // File offset of section header table. |
282 | off_t shoff_; | |
bae7f79e ILT |
283 | // Offset of SHT_STRTAB section holding section names. |
284 | unsigned int shstrndx_; | |
285 | // Index of SHT_SYMTAB section. | |
286 | unsigned int symtab_shnum_; | |
14bfc3f5 ILT |
287 | // The entries in the symbol table for the external symbols. |
288 | Symbol** symbols_; | |
bae7f79e ILT |
289 | }; |
290 | ||
54dc6425 | 291 | // A class to manage the list of all objects. |
a2fb1b05 | 292 | |
54dc6425 ILT |
293 | class Input_objects |
294 | { | |
295 | public: | |
296 | Input_objects() | |
274e99f9 | 297 | : object_list_(), any_dynamic_(false) |
54dc6425 ILT |
298 | { } |
299 | ||
300 | // The type of the list of input objects. | |
301 | typedef std::list<Object*> Object_list; | |
302 | ||
303 | // Add an object to the list. | |
304 | void | |
305 | add_object(Object*); | |
306 | ||
307 | // Iterate over all objects. | |
308 | Object_list::const_iterator | |
309 | begin() const | |
310 | { return this->object_list_.begin(); } | |
311 | ||
312 | Object_list::const_iterator | |
313 | end() const | |
314 | { return this->object_list_.end(); } | |
315 | ||
316 | // Return whether we have seen any dynamic objects. | |
317 | bool | |
318 | any_dynamic() const | |
319 | { return this->any_dynamic_; } | |
320 | ||
321 | private: | |
322 | Input_objects(const Input_objects&); | |
323 | Input_objects& operator=(const Input_objects&); | |
324 | ||
325 | Object_list object_list_; | |
326 | bool any_dynamic_; | |
327 | }; | |
a2fb1b05 | 328 | |
bae7f79e ILT |
329 | // Return an Object appropriate for the input file. P is BYTES long, |
330 | // and holds the ELF header. | |
331 | ||
332 | extern Object* make_elf_object(const std::string& name, Input_file*, | |
333 | off_t offset, const unsigned char* p, | |
334 | off_t bytes); | |
335 | ||
336 | } // end namespace gold | |
337 | ||
338 | #endif // !defined(GOLD_OBJECT_H) |