1 // script-sections.h -- linker script SECTIONS for gold -*- C++ -*-
3 // Copyright (C) 2008-2016 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 // This is for the support of the SECTIONS clause in linker scripts.
25 #ifndef GOLD_SCRIPT_SECTIONS_H
26 #define GOLD_SCRIPT_SECTIONS_H
35 struct Parser_output_section_header;
36 struct Parser_output_section_trailer;
37 struct Input_section_spec;
39 class Sections_element;
43 class Output_section_definition;
46 class Orphan_section_placement;
51 // This is a list, not a vector, because we insert orphan sections
53 typedef std::list<Sections_element*> Sections_elements;
55 // Logical script section types. We map section types returned by the
56 // parser into these since some section types have the same semantics.
59 // No section type specified.
61 // Section is NOLOAD. We allocate space in the output but section
62 // is not loaded in runtime.
64 // No space is allocated to section.
70 // Start a SECTIONS clause.
74 // Finish a SECTIONS clause.
78 // Return whether we ever saw a SECTIONS clause. If we did, then
79 // all section layout needs to go through this class.
81 saw_sections_clause() const
82 { return this->saw_sections_clause_; }
84 // Return whether we are currently processing a SECTIONS clause.
86 in_sections_clause() const
87 { return this->in_sections_clause_; }
89 // Return whether we ever saw a PHDRS clause. We ignore the PHDRS
90 // clause unless we also saw a SECTIONS clause.
92 saw_phdrs_clause() const
93 { return this->saw_sections_clause_ && this->phdrs_elements_ != NULL; }
95 // Start processing entries for an output section.
97 start_output_section(const char* name, size_t namelen,
98 const Parser_output_section_header*);
100 // Finish processing entries for an output section.
102 finish_output_section(const Parser_output_section_trailer*);
104 // Add a data item to the current output section.
106 add_data(int size, bool is_signed, Expression* val);
108 // Add a symbol to be defined.
110 add_symbol_assignment(const char* name, size_t length, Expression* value,
111 bool provide, bool hidden);
113 // Add an assignment to the special dot symbol.
115 add_dot_assignment(Expression* value);
119 add_assertion(Expression* check, const char* message, size_t messagelen);
121 // Add a setting for the fill value.
123 add_fill(Expression* val);
125 // Add an input section specification.
127 add_input_section(const Input_section_spec* spec, bool keep);
129 // Saw DATA_SEGMENT_ALIGN.
131 data_segment_align();
133 // Saw DATA_SEGMENT_RELRO_END.
135 data_segment_relro_end();
137 // Create any required sections.
139 create_sections(Layout*);
141 // Add any symbols we are defining to the symbol table.
143 add_symbols_to_table(Symbol_table*);
145 // Finalize symbol values and check assertions.
147 finalize_symbols(Symbol_table* symtab, const Layout* layout);
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
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.
168 output_section_name(const char* file_name, const char* section_name,
169 Output_section*** output_section_slot,
170 Section_type* pscript_section_type,
173 // Place a marker for an orphan output section into the SECTIONS
176 place_orphan(Output_section* os);
178 // Set the addresses of all the output sections. Return the segment
179 // which holds the file header and segment headers, if any.
181 set_section_addresses(Symbol_table*, Layout*);
183 // Add a program header definition.
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);
189 // Return the number of segments we expect to create based on the
192 expected_segment_count(const Layout*) const;
194 // Add the file header and segment header to non-load segments as
195 // specified by the PHDRS clause.
197 put_headers_in_phdrs(Output_data* file_header, Output_data* segment_headers);
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
205 get_output_section_info(const char* name, uint64_t* address,
206 uint64_t* load_address, uint64_t* addralign,
207 uint64_t* size) const;
209 // Release all Output_segments. This is used in relaxation.
213 // Whether we ever saw a SEGMENT_START expression, the presence of which
214 // changes the behaviour of -Ttext, -Tdata and -Tbss options.
216 saw_segment_start_expression() const
217 { return this->saw_segment_start_expression_; }
219 // Set the flag which indicates whether we saw a SEGMENT_START expression.
221 set_saw_segment_start_expression(bool value)
222 { this->saw_segment_start_expression_ = value; }
224 // Add a memory region.
226 add_memory_region(const char*, size_t, unsigned int,
227 Expression*, Expression*);
229 // Find a memory region's origin.
231 find_memory_region_origin(const char*, size_t);
233 // Find a memory region's length.
235 find_memory_region_length(const char*, size_t);
237 // Find a memory region by name.
239 find_memory_region(const char*, size_t);
241 // Find a memory region that should be used by a given output section.
243 find_memory_region(Output_section_definition*, bool, bool,
244 Output_section_definition**);
246 // Returns true if the provide block of memory is contained
247 // within a memory region.
249 block_in_region(Symbol_table*, Layout*, uint64_t, uint64_t) const;
251 // Set the memory region of the section.
253 set_memory_region(Memory_region*, bool);
255 // Print the contents to the FILE. This is for debugging.
259 // Used for orphan sections.
260 typedef Sections_elements::iterator Elements_iterator;
263 typedef std::vector<Memory_region*> Memory_regions;
264 typedef std::vector<Phdrs_element*> Phdrs_elements;
268 create_segments(Layout*, uint64_t);
270 // Create PT_NOTE and PT_TLS segments.
272 create_note_and_tls_segments(Layout*, const std::vector<Output_section*>*);
274 // Return whether the section is a BSS section.
276 is_bss_section(const Output_section*);
278 // Return the total size of the headers.
280 total_header_size(Layout* layout) const;
282 // Return the amount we have to subtract from the LMA to accommodate
283 // headers of the given size.
285 header_size_adjustment(uint64_t lma, size_t sizeof_headers) const;
287 // Create the segments from a PHDRS clause.
289 create_segments_from_phdrs_clause(Layout* layout, uint64_t);
291 // Attach sections to segments from a PHDRS clause.
293 attach_sections_using_phdrs_clause(Layout*);
295 // Set addresses of segments from a PHDRS clause.
297 set_phdrs_clause_addresses(Layout*, uint64_t);
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.
320 // Whether we have seen SEGMENT_START.
321 bool saw_segment_start_expression_;
322 // Whether we have created all necessary segments.
323 bool segments_created_;
326 // Attributes for memory regions.
329 MEM_EXECUTABLE = (1 << 0),
330 MEM_WRITEABLE = (1 << 1),
331 MEM_READABLE = (1 << 2),
332 MEM_ALLOCATABLE = (1 << 3),
333 MEM_INITIALIZED = (1 << 4),
334 MEM_ATTR_MASK = (1 << 5) - 1
337 } // End namespace gold.
339 #endif // !defined(GOLD_SCRIPT_SECTIONS_H