| 1 | // script-sections.h -- linker script SECTIONS for gold -*- C++ -*- |
| 2 | |
| 3 | // Copyright 2008, 2009 Free Software Foundation, Inc. |
| 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 | |
| 23 | // This is for the support of the SECTIONS clause in linker scripts. |
| 24 | |
| 25 | #ifndef GOLD_SCRIPT_SECTIONS_H |
| 26 | #define GOLD_SCRIPT_SECTIONS_H |
| 27 | |
| 28 | #include <cstdio> |
| 29 | #include <list> |
| 30 | #include <vector> |
| 31 | |
| 32 | namespace gold |
| 33 | { |
| 34 | |
| 35 | struct Parser_output_section_header; |
| 36 | struct Parser_output_section_trailer; |
| 37 | struct Input_section_spec; |
| 38 | class Expression; |
| 39 | class Sections_element; |
| 40 | class Memory_region; |
| 41 | class Phdrs_element; |
| 42 | class Output_data; |
| 43 | class Output_section_definition; |
| 44 | class Output_section; |
| 45 | class Output_segment; |
| 46 | class Orphan_section_placement; |
| 47 | |
| 48 | class Script_sections |
| 49 | { |
| 50 | public: |
| 51 | // This is a list, not a vector, because we insert orphan sections |
| 52 | // in the middle. |
| 53 | typedef std::list<Sections_element*> Sections_elements; |
| 54 | |
| 55 | // Logical script section types. We map section types returned by the |
| 56 | // parser into these since some section types have the same semantics. |
| 57 | enum Section_type |
| 58 | { |
| 59 | // No section type specified. |
| 60 | ST_NONE, |
| 61 | // Section is NOLOAD. We allocate space in the output but section |
| 62 | // is not loaded in runtime. |
| 63 | ST_NOLOAD, |
| 64 | // No space is allocated to section. |
| 65 | ST_NOALLOC |
| 66 | }; |
| 67 | |
| 68 | Script_sections(); |
| 69 | |
| 70 | // Start a SECTIONS clause. |
| 71 | void |
| 72 | start_sections(); |
| 73 | |
| 74 | // Finish a SECTIONS clause. |
| 75 | void |
| 76 | finish_sections(); |
| 77 | |
| 78 | // Return whether we ever saw a SECTIONS clause. If we did, then |
| 79 | // all section layout needs to go through this class. |
| 80 | bool |
| 81 | saw_sections_clause() const |
| 82 | { return this->saw_sections_clause_; } |
| 83 | |
| 84 | // Return whether we are currently processing a SECTIONS clause. |
| 85 | bool |
| 86 | in_sections_clause() const |
| 87 | { return this->in_sections_clause_; } |
| 88 | |
| 89 | // Return whether we ever saw a PHDRS clause. We ignore the PHDRS |
| 90 | // clause unless we also saw a SECTIONS clause. |
| 91 | bool |
| 92 | saw_phdrs_clause() const |
| 93 | { return this->saw_sections_clause_ && this->phdrs_elements_ != NULL; } |
| 94 | |
| 95 | // Start processing entries for an output section. |
| 96 | void |
| 97 | start_output_section(const char* name, size_t namelen, |
| 98 | const Parser_output_section_header*); |
| 99 | |
| 100 | // Finish processing entries for an output section. |
| 101 | void |
| 102 | finish_output_section(const Parser_output_section_trailer*); |
| 103 | |
| 104 | // Add a data item to the current output section. |
| 105 | void |
| 106 | add_data(int size, bool is_signed, Expression* val); |
| 107 | |
| 108 | // Add a symbol to be defined. |
| 109 | void |
| 110 | add_symbol_assignment(const char* name, size_t length, Expression* value, |
| 111 | bool provide, bool hidden); |
| 112 | |
| 113 | // Add an assignment to the special dot symbol. |
| 114 | void |
| 115 | add_dot_assignment(Expression* value); |
| 116 | |
| 117 | // Add an assertion. |
| 118 | void |
| 119 | add_assertion(Expression* check, const char* message, size_t messagelen); |
| 120 | |
| 121 | // Add a setting for the fill value. |
| 122 | void |
| 123 | add_fill(Expression* val); |
| 124 | |
| 125 | // Add an input section specification. |
| 126 | void |
| 127 | add_input_section(const Input_section_spec* spec, bool keep); |
| 128 | |
| 129 | // Saw DATA_SEGMENT_ALIGN. |
| 130 | void |
| 131 | data_segment_align(); |
| 132 | |
| 133 | // Saw DATA_SEGMENT_RELRO_END. |
| 134 | void |
| 135 | data_segment_relro_end(); |
| 136 | |
| 137 | // Create any required sections. |
| 138 | void |
| 139 | create_sections(Layout*); |
| 140 | |
| 141 | // Add any symbols we are defining to the symbol table. |
| 142 | void |
| 143 | add_symbols_to_table(Symbol_table*); |
| 144 | |
| 145 | // Finalize symbol values and check assertions. |
| 146 | void |
| 147 | finalize_symbols(Symbol_table* symtab, const Layout* layout); |
| 148 | |
| 149 | // Find the name of the output section to use for an input file name |
| 150 | // and section name. This returns a name, and sets |
| 151 | // *OUTPUT_SECTION_SLOT to point to the address where the actual |
| 152 | // output section may be stored. |
| 153 | // 1) If the input section should be discarded, this returns NULL |
| 154 | // and sets *OUTPUT_SECTION_SLOT to NULL. |
| 155 | // 2) If the input section is mapped by the SECTIONS clause, this |
| 156 | // returns the name to use for the output section (in permanent |
| 157 | // storage), and sets *OUTPUT_SECTION_SLOT to point to where the |
| 158 | // output section should be stored. **OUTPUT_SECTION_SLOT will be |
| 159 | // non-NULL if we have seen this output section already. |
| 160 | // 3) If the input section is not mapped by the SECTIONS clause, |
| 161 | // this returns SECTION_NAME, and sets *OUTPUT_SECTION_SLOT to |
| 162 | // NULL. |
| 163 | // PSCRIPT_SECTION_TYPE points to a location for returning the section |
| 164 | // type specified in script. This can be SCRIPT_SECTION_TYPE_NONE if |
| 165 | // no type is specified. |
| 166 | // *KEEP indicates whether the section should survive garbage collection. |
| 167 | const char* |
| 168 | output_section_name(const char* file_name, const char* section_name, |
| 169 | Output_section*** output_section_slot, |
| 170 | Section_type* pscript_section_type, |
| 171 | bool* keep); |
| 172 | |
| 173 | // Place a marker for an orphan output section into the SECTIONS |
| 174 | // clause. |
| 175 | void |
| 176 | place_orphan(Output_section* os); |
| 177 | |
| 178 | // Set the addresses of all the output sections. Return the segment |
| 179 | // which holds the file header and segment headers, if any. |
| 180 | Output_segment* |
| 181 | set_section_addresses(Symbol_table*, Layout*); |
| 182 | |
| 183 | // Add a program header definition. |
| 184 | void |
| 185 | add_phdr(const char* name, size_t namelen, unsigned int type, |
| 186 | bool filehdr, bool phdrs, bool is_flags_valid, unsigned int flags, |
| 187 | Expression* load_address); |
| 188 | |
| 189 | // Return the number of segments we expect to create based on the |
| 190 | // SECTIONS clause. |
| 191 | size_t |
| 192 | expected_segment_count(const Layout*) const; |
| 193 | |
| 194 | // Add the file header and segment header to non-load segments as |
| 195 | // specified by the PHDRS clause. |
| 196 | void |
| 197 | put_headers_in_phdrs(Output_data* file_header, Output_data* segment_headers); |
| 198 | |
| 199 | // Look for an output section by name and return the address, the |
| 200 | // load address, the alignment, and the size. This is used when an |
| 201 | // expression refers to an output section which was not actually |
| 202 | // created. This returns true if the section was found, false |
| 203 | // otherwise. |
| 204 | bool |
| 205 | get_output_section_info(const char* name, uint64_t* address, |
| 206 | uint64_t* load_address, uint64_t* addralign, |
| 207 | uint64_t* size) const; |
| 208 | |
| 209 | // Release all Output_segments. This is used in relaxation. |
| 210 | void |
| 211 | release_segments(); |
| 212 | |
| 213 | // Whether we ever saw a SEGMENT_START expression, the presence of which |
| 214 | // changes the behaviour of -Ttext, -Tdata and -Tbss options. |
| 215 | bool |
| 216 | saw_segment_start_expression() const |
| 217 | { return this->saw_segment_start_expression_; } |
| 218 | |
| 219 | // Set the flag which indicates whether we saw a SEGMENT_START expression. |
| 220 | void |
| 221 | set_saw_segment_start_expression(bool value) |
| 222 | { this->saw_segment_start_expression_ = value; } |
| 223 | |
| 224 | // Add a memory region. |
| 225 | void |
| 226 | add_memory_region(const char*, size_t, unsigned int, |
| 227 | Expression*, Expression*); |
| 228 | |
| 229 | // Find a memory region's origin. |
| 230 | Expression* |
| 231 | find_memory_region_origin(const char*, size_t); |
| 232 | |
| 233 | // Find a memory region's length. |
| 234 | Expression* |
| 235 | find_memory_region_length(const char*, size_t); |
| 236 | |
| 237 | // Find a memory region by name. |
| 238 | Memory_region* |
| 239 | find_memory_region(const char*, size_t); |
| 240 | |
| 241 | // Find a memory region that should be used by a given output section. |
| 242 | Memory_region* |
| 243 | find_memory_region(Output_section_definition*, bool, |
| 244 | Output_section_definition**); |
| 245 | |
| 246 | // Returns true if the provide block of memory is contained |
| 247 | // within a memory region. |
| 248 | bool |
| 249 | block_in_region(Symbol_table*, Layout*, uint64_t, uint64_t) const; |
| 250 | |
| 251 | // Set the memory region of the section. |
| 252 | void |
| 253 | set_memory_region(Memory_region*, bool); |
| 254 | |
| 255 | // Print the contents to the FILE. This is for debugging. |
| 256 | void |
| 257 | print(FILE*) const; |
| 258 | |
| 259 | // Used for orphan sections. |
| 260 | typedef Sections_elements::iterator Elements_iterator; |
| 261 | |
| 262 | private: |
| 263 | typedef std::vector<Memory_region*> Memory_regions; |
| 264 | typedef std::vector<Phdrs_element*> Phdrs_elements; |
| 265 | |
| 266 | // Create segments. |
| 267 | Output_segment* |
| 268 | create_segments(Layout*, uint64_t); |
| 269 | |
| 270 | // Create PT_NOTE and PT_TLS segments. |
| 271 | void |
| 272 | create_note_and_tls_segments(Layout*, const std::vector<Output_section*>*); |
| 273 | |
| 274 | // Return whether the section is a BSS section. |
| 275 | static bool |
| 276 | is_bss_section(const Output_section*); |
| 277 | |
| 278 | // Return the total size of the headers. |
| 279 | size_t |
| 280 | total_header_size(Layout* layout) const; |
| 281 | |
| 282 | // Return the amount we have to subtract from the LMA to accomodate |
| 283 | // headers of the given size. |
| 284 | uint64_t |
| 285 | header_size_adjustment(uint64_t lma, size_t sizeof_headers) const; |
| 286 | |
| 287 | // Create the segments from a PHDRS clause. |
| 288 | Output_segment* |
| 289 | create_segments_from_phdrs_clause(Layout* layout, uint64_t); |
| 290 | |
| 291 | // Attach sections to segments from a PHDRS clause. |
| 292 | void |
| 293 | attach_sections_using_phdrs_clause(Layout*); |
| 294 | |
| 295 | // Set addresses of segments from a PHDRS clause. |
| 296 | Output_segment* |
| 297 | set_phdrs_clause_addresses(Layout*, uint64_t); |
| 298 | |
| 299 | // True if we ever saw a SECTIONS clause. |
| 300 | bool saw_sections_clause_; |
| 301 | // True if we are currently processing a SECTIONS clause. |
| 302 | bool in_sections_clause_; |
| 303 | // The list of elements in the SECTIONS clause. |
| 304 | Sections_elements* sections_elements_; |
| 305 | // The current output section, if there is one. |
| 306 | Output_section_definition* output_section_; |
| 307 | // The list of memory regions in the MEMORY clause. |
| 308 | Memory_regions* memory_regions_; |
| 309 | // The list of program headers in the PHDRS clause. |
| 310 | Phdrs_elements* phdrs_elements_; |
| 311 | // Where to put orphan sections. |
| 312 | Orphan_section_placement* orphan_section_placement_; |
| 313 | // A pointer to the last Sections_element when we see |
| 314 | // DATA_SEGMENT_ALIGN. |
| 315 | Sections_elements::iterator data_segment_align_start_; |
| 316 | // Whether we have seen DATA_SEGMENT_ALIGN. |
| 317 | bool saw_data_segment_align_; |
| 318 | // Whether we have seen DATA_SEGMENT_RELRO_END. |
| 319 | bool saw_relro_end_; |
| 320 | // Whether we have seen SEGMENT_START. |
| 321 | bool saw_segment_start_expression_; |
| 322 | }; |
| 323 | |
| 324 | // Attributes for memory regions. |
| 325 | enum |
| 326 | { |
| 327 | MEM_EXECUTABLE = (1 << 0), |
| 328 | MEM_WRITEABLE = (1 << 1), |
| 329 | MEM_READABLE = (1 << 2), |
| 330 | MEM_ALLOCATABLE = (1 << 3), |
| 331 | MEM_INITIALIZED = (1 << 4), |
| 332 | MEM_ATTR_MASK = (1 << 5) - 1 |
| 333 | }; |
| 334 | |
| 335 | } // End namespace gold. |
| 336 | |
| 337 | #endif // !defined(GOLD_SCRIPT_SECTIONS_H |