1 // layout.h -- lay out output file sections for gold -*- C++ -*-
12 #include "workqueue.h"
14 #include "stringpool.h"
22 class Output_section_symtab
;
23 class Output_section_headers
;
28 // This Task handles mapping the input sections to output sections and
29 // laying them out in memory.
31 class Layout_task
: public Task
34 // OPTIONS is the command line options, INPUT_OBJECTS is the list of
35 // input objects, THIS_BLOCKER is a token which blocks this task
36 // from executing until all the input symbols have been read.
37 Layout_task(const General_options
& options
,
38 const Input_objects
* input_objects
,
40 Task_token
* this_blocker
)
41 : options_(options
), input_objects_(input_objects
), symtab_(symtab
),
42 this_blocker_(this_blocker
)
47 // The standard Task methods.
50 is_runnable(Workqueue
*);
59 Layout_task(const Layout_task
&);
60 Layout_task
& operator=(const Layout_task
&);
62 const General_options
& options_
;
63 const Input_objects
* input_objects_
;
64 Symbol_table
* symtab_
;
65 Task_token
* this_blocker_
;
68 // This class handles the details of laying out input sections.
73 Layout(const General_options
& options
);
75 // Initialize the object.
79 // Given an input section named NAME with data in SHDR from the
80 // object file OBJECT, return the output section where this input
81 // section should go. Set *OFFSET to the offset within the output
83 template<int size
, bool big_endian
>
85 layout(Object
*object
, const char* name
,
86 const elfcpp::Shdr
<size
, big_endian
>& shdr
, off_t
* offset
);
88 // Return the Stringpool used for symbol names.
91 { return &this->sympool_
; }
93 // Return whether a section is a .gnu.linkonce section, given the
96 is_linkonce(const char* name
)
97 { return strncmp(name
, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
99 // Record the signature of a comdat section, and return whether to
100 // include it in the link. The GROUP parameter is true for a
101 // section group signature, false for a signature derived from a
102 // .gnu.linkonce section.
104 add_comdat(const char*, bool group
);
106 // Finalize the layout after all the input sections have been added.
108 finalize(const Input_objects
*, Symbol_table
*);
110 // Write out data not associated with an input file or the symbol
113 write_data(Output_file
*) const;
115 // The list of segments.
117 typedef std::vector
<Output_segment
*> Segment_list
;
119 // The list of sections not attached to a segment.
121 typedef std::list
<Output_section
*> Section_list
;
123 // The list of information to write out which is not attached to
124 // either a section or a segment.
125 typedef std::list
<Output_data
*> Data_list
;
128 Layout(const Layout
&);
129 Layout
& operator=(const Layout
&);
131 // Mapping from .gnu.linkonce section names to output section names.
132 struct Linkonce_mapping
138 static const Linkonce_mapping linkonce_mapping
[];
139 static const int linkonce_mapping_count
;
141 // Find the first read-only PT_LOAD segment, creating one if
144 find_first_load_seg();
146 // Set the final file offsets of all the segments.
148 set_segment_offsets(const Target
*, Output_segment
*);
150 // Set the final file offsets of all the sections not associated
153 set_section_offsets(off_t
);
155 // Create the output sections for the symbol table.
157 create_symtab_sections(int size
, const Input_objects
*, Symbol_table
*, off_t
*,
158 Output_section
** osymtab
,
159 Output_section
** ostrtab
);
161 // Create the .shstrtab section.
165 // Create the section header table.
166 Output_section_headers
*
167 create_shdrs(int size
, bool big_endian
, off_t
*);
169 // Return whether to include this section in the link.
170 template<int size
, bool big_endian
>
172 include_section(Object
* object
, const char* name
,
173 const elfcpp::Shdr
<size
, big_endian
>&);
175 // Return the output section name to use for a linkonce section
178 linkonce_output_name(const char* name
);
180 // Create a new Output_section.
182 make_output_section(const char* name
, elfcpp::Elf_Word type
,
183 elfcpp::Elf_Xword flags
);
185 // Return whether SEG1 comes before SEG2 in the output file.
187 segment_precedes(const Output_segment
* seg1
, const Output_segment
* seg2
);
189 // Map from section flags to segment flags.
190 static elfcpp::Elf_Word
191 section_flags_to_segment(elfcpp::Elf_Xword flags
);
193 // A mapping used for group signatures.
194 typedef Unordered_map
<std::string
, bool> Signatures
;
196 // Mapping from input section name/type/flags to output section. We
197 // use canonicalized strings here.
199 typedef std::pair
<const char*,
200 std::pair
<elfcpp::Elf_Word
, elfcpp::Elf_Xword
> > Key
;
205 operator()(const Key
& k
) const;
208 typedef Unordered_map
<Key
, Output_section
*, Hash_key
> Section_name_map
;
210 // A comparison class for segments.
212 struct Compare_segments
215 operator()(const Output_segment
* seg1
, const Output_segment
* seg2
)
216 { return Layout::segment_precedes(seg1
, seg2
); }
219 // A reference to the options on the command line.
220 const General_options
& options_
;
221 // The index of the last output section.
222 unsigned int last_shndx_
;
223 // The output section names.
224 Stringpool namepool_
;
225 // The output symbol names.
227 // The list of group sections and linkonce sections which we have seen.
228 Signatures signatures_
;
229 // The mapping from input section name/type/flags to output sections.
230 Section_name_map section_name_map_
;
231 // The list of output segments.
232 Segment_list segment_list_
;
233 // The list of output sections which are not attached to any output
235 Section_list section_list_
;
236 // The list of sections which require special output because they
237 // are not comprised of input sections.
238 Data_list special_output_list_
;
241 // This task handles writing out data which is not part of a section
244 class Write_data_task
: public Task
247 Write_data_task(const Layout
* layout
, Output_file
* of
,
248 Task_token
* final_blocker
)
249 : layout_(layout
), of_(of
), final_blocker_(final_blocker
)
252 // The standard Task methods.
255 is_runnable(Workqueue
*);
264 const Layout
* layout_
;
266 Task_token
* final_blocker_
;
269 // This task handles writing out the global symbols.
271 class Write_symbols_task
: public Task
274 Write_symbols_task(const Symbol_table
* symtab
, const Target
* target
,
275 const Stringpool
* sympool
, Output_file
* of
,
276 Task_token
* final_blocker
)
277 : symtab_(symtab
), target_(target
), sympool_(sympool
), of_(of
),
278 final_blocker_(final_blocker
)
281 // The standard Task methods.
284 is_runnable(Workqueue
*);
293 const Symbol_table
* symtab_
;
294 const Target
* target_
;
295 const Stringpool
* sympool_
;
297 Task_token
* final_blocker_
;
300 // This task handles closing the file.
302 class Close_task
: public Task
305 Close_task(Output_file
* of
, Task_token
* final_blocker
)
306 : of_(of
), final_blocker_(final_blocker
)
309 // The standard task methods.
312 is_runnable(Workqueue
*);
322 Task_token
* final_blocker_
;
325 } // End namespace gold.
327 #endif // !defined(GOLD_LAYOUT_H)