1 // layout.h -- lay out output file sections for gold -*- C++ -*-
12 #include "workqueue.h"
14 #include "stringpool.h"
21 class Output_section_symtab
;
25 // This Task handles mapping the input sections to output sections and
26 // laying them out in memory.
28 class Layout_task
: public Task
31 // OPTIONS is the command line options, INPUT_OBJECTS is the list of
32 // input objects, THIS_BLOCKER is a token which blocks this task
33 // from executing until all the input symbols have been read.
34 Layout_task(const General_options
& options
,
35 const Input_objects
* input_objects
,
36 Task_token
* this_blocker
)
37 : options_(options
), input_objects_(input_objects
),
38 this_blocker_(this_blocker
)
43 // The standard Task methods.
46 is_runnable(Workqueue
*);
55 Layout_task(const Layout_task
&);
56 Layout_task
& operator=(const Layout_task
&);
58 const General_options
& options_
;
59 const Input_objects
* input_objects_
;
60 Task_token
* this_blocker_
;
63 // This class handles the details of laying out input sections.
68 Layout(const General_options
& options
);
70 // Initialize the object.
74 // Given an input section named NAME with data in SHDR from the
75 // object file OBJECT, return the output section where this input
76 // section should go. Set *OFFSET to the offset within the output
78 template<int size
, bool big_endian
>
80 layout(Object
*object
, const char* name
,
81 const elfcpp::Shdr
<size
, big_endian
>& shdr
, off_t
* offset
);
83 // Return whether a section is a .gnu.linkonce section, given the
86 is_linkonce(const char* name
)
87 { return strncmp(name
, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
89 // Record the signature of a comdat section, and return whether to
90 // include it in the link. The GROUP parameter is true for a
91 // section group signature, false for a signature derived from a
92 // .gnu.linkonce section.
94 add_comdat(const char*, bool group
);
96 // Finalize the layout after all the input sections have been added.
98 finalize(const Input_objects
*);
100 // The list of segments.
102 typedef std::vector
<Output_segment
*> Segment_list
;
104 // The list of sections not attached to a segment.
106 typedef std::list
<Output_section
*> Section_list
;
108 // The list of information to write out which is not attached to
109 // either a section or a segment.
110 typedef std::list
<Output_data
*> Data_list
;
113 Layout(const Layout
&);
114 Layout
& operator=(const Layout
&);
116 // Mapping from .gnu.linkonce section names to output section names.
117 struct Linkonce_mapping
123 static const Linkonce_mapping linkonce_mapping
[];
124 static const int linkonce_mapping_count
;
126 // Lay out the local symbols from a SHT_SYMTAB section.
127 template<int size
, bool big_endian
>
129 add_symtab_locals(Object
* object
, const elfcpp::Shdr
<size
, big_endian
>&);
131 // Create the output sections for the symbol table.
133 create_symtab_sections();
135 // Finalize the symbol table.
139 // Return whether to include this section in the link.
140 template<int size
, bool big_endian
>
142 include_section(Object
* object
, const char* name
,
143 const elfcpp::Shdr
<size
, big_endian
>&);
145 // Return the output section name to use for a linkonce section
148 linkonce_output_name(const char* name
);
150 // Create a new Output_section.
152 make_output_section(const char* name
, elfcpp::Elf_Word type
,
153 elfcpp::Elf_Xword flags
);
155 // Return whether SEG1 comes before SEG2 in the output file.
157 Layout::segment_precedes(const Output_segment
* seg1
,
158 const Output_segment
* seg2
);
160 // Map from section flags to segment flags.
161 static elfcpp::Elf_Word
162 section_flags_to_segment(elfcpp::Elf_Xword flags
);
164 // A mapping used for group signatures.
165 typedef Unordered_map
<std::string
, bool> Signatures
;
167 // Mapping from input section name/type/flags to output section. We
168 // use canonicalized strings here.
170 typedef std::pair
<const char*,
171 std::pair
<elfcpp::Elf_Word
, elfcpp::Elf_Xword
> > Key
;
176 operator()(const Key
& k
) const;
179 typedef Unordered_map
<Key
, Output_section
*, Hash_key
> Section_name_map
;
181 // A comparison class for segments.
183 struct Compare_segments
186 operator()(const Output_segment
* seg1
, const Output_segment
* seg2
)
187 { return Layout::segment_precedes(seg1
, seg2
); }
190 // A reference to the options on the command line.
191 const General_options
& options_
;
192 // The output section names.
193 Stringpool namepool_
;
194 // The list of group sections and linkonce sections which we have seen.
195 Signatures signatures_
;
196 // The mapping from input section name/type/flags to output sections.
197 Section_name_map section_name_map_
;
198 // The list of output segments.
199 Segment_list segment_list_
;
200 // The list of output sections which are not attached to any output
202 Section_list section_list_
;
203 // The list of output data objects which are not attached to any
204 // output section or output segment.
205 Data_list data_list_
;
208 } // End namespace gold.
210 #endif // !defined(GOLD_LAYOUT_H)