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a2fb1b05 ILT |
1 | // layout.h -- lay out output file sections for gold -*- C++ -*- |
2 | ||
3 | #ifndef GOLD_LAYOUT_H | |
4 | #define GOLD_LAYOUT_H | |
5 | ||
6 | #include <list> | |
7 | #include <string> | |
8 | #include <utility> | |
9 | #include <vector> | |
10 | ||
11 | #include "options.h" | |
12 | #include "workqueue.h" | |
13 | #include "object.h" | |
14 | #include "stringpool.h" | |
15 | ||
16 | namespace gold | |
17 | { | |
18 | ||
54dc6425 | 19 | class Input_objects; |
a2fb1b05 | 20 | class Output_section; |
54dc6425 | 21 | class Output_section_symtab; |
a2fb1b05 | 22 | class Output_segment; |
54dc6425 | 23 | class Output_data; |
a2fb1b05 ILT |
24 | |
25 | // This Task handles mapping the input sections to output sections and | |
26 | // laying them out in memory. | |
27 | ||
28 | class Layout_task : public Task | |
29 | { | |
30 | public: | |
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. | |
54dc6425 ILT |
34 | Layout_task(const General_options& options, |
35 | const Input_objects* input_objects, | |
a2fb1b05 ILT |
36 | Task_token* this_blocker) |
37 | : options_(options), input_objects_(input_objects), | |
38 | this_blocker_(this_blocker) | |
39 | { } | |
40 | ||
41 | ~Layout_task(); | |
42 | ||
43 | // The standard Task methods. | |
44 | ||
45 | Is_runnable_type | |
46 | is_runnable(Workqueue*); | |
47 | ||
48 | Task_locker* | |
49 | locks(Workqueue*); | |
50 | ||
51 | void | |
52 | run(Workqueue*); | |
53 | ||
54 | private: | |
55 | Layout_task(const Layout_task&); | |
56 | Layout_task& operator=(const Layout_task&); | |
57 | ||
58 | const General_options& options_; | |
54dc6425 | 59 | const Input_objects* input_objects_; |
a2fb1b05 ILT |
60 | Task_token* this_blocker_; |
61 | }; | |
62 | ||
63 | // This class handles the details of laying out input sections. | |
64 | ||
65 | class Layout | |
66 | { | |
67 | public: | |
54dc6425 ILT |
68 | Layout(const General_options& options); |
69 | ||
70 | // Initialize the object. | |
71 | void | |
72 | init(); | |
a2fb1b05 ILT |
73 | |
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 | |
77 | // section. | |
78 | template<int size, bool big_endian> | |
79 | Output_section* | |
80 | layout(Object *object, const char* name, | |
81 | const elfcpp::Shdr<size, big_endian>& shdr, off_t* offset); | |
82 | ||
83 | // Return whether a section is a .gnu.linkonce section, given the | |
84 | // section name. | |
85 | static inline bool | |
86 | is_linkonce(const char* name) | |
87 | { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; } | |
88 | ||
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. | |
93 | bool | |
94 | add_comdat(const char*, bool group); | |
95 | ||
54dc6425 ILT |
96 | // Finalize the layout after all the input sections have been added. |
97 | void | |
98 | finalize(const Input_objects*); | |
99 | ||
100 | // The list of segments. | |
101 | ||
102 | typedef std::vector<Output_segment*> Segment_list; | |
103 | ||
104 | // The list of sections not attached to a segment. | |
105 | ||
106 | typedef std::list<Output_section*> Section_list; | |
107 | ||
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; | |
111 | ||
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112 | private: |
113 | Layout(const Layout&); | |
114 | Layout& operator=(const Layout&); | |
115 | ||
116 | // Mapping from .gnu.linkonce section names to output section names. | |
117 | struct Linkonce_mapping | |
118 | { | |
119 | const char* from; | |
120 | int fromlen; | |
121 | const char* to; | |
122 | }; | |
123 | static const Linkonce_mapping linkonce_mapping[]; | |
124 | static const int linkonce_mapping_count; | |
125 | ||
54dc6425 ILT |
126 | // Lay out the local symbols from a SHT_SYMTAB section. |
127 | template<int size, bool big_endian> | |
128 | void | |
129 | add_symtab_locals(Object* object, const elfcpp::Shdr<size, big_endian>&); | |
130 | ||
131 | // Create the output sections for the symbol table. | |
132 | void | |
133 | create_symtab_sections(); | |
134 | ||
135 | // Finalize the symbol table. | |
136 | void | |
137 | finalize_symtab(); | |
138 | ||
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139 | // Return whether to include this section in the link. |
140 | template<int size, bool big_endian> | |
141 | bool | |
142 | include_section(Object* object, const char* name, | |
143 | const elfcpp::Shdr<size, big_endian>&); | |
144 | ||
145 | // Return the output section name to use for a linkonce section | |
146 | // name. | |
147 | static const char* | |
148 | linkonce_output_name(const char* name); | |
149 | ||
150 | // Create a new Output_section. | |
151 | Output_section* | |
152 | make_output_section(const char* name, elfcpp::Elf_Word type, | |
153 | elfcpp::Elf_Xword flags); | |
154 | ||
155 | // Return whether SEG1 comes before SEG2 in the output file. | |
156 | static bool | |
b3168e9d | 157 | segment_precedes(const Output_segment* seg1, const Output_segment* seg2); |
a2fb1b05 ILT |
158 | |
159 | // Map from section flags to segment flags. | |
160 | static elfcpp::Elf_Word | |
161 | section_flags_to_segment(elfcpp::Elf_Xword flags); | |
162 | ||
163 | // A mapping used for group signatures. | |
164 | typedef Unordered_map<std::string, bool> Signatures; | |
165 | ||
166 | // Mapping from input section name/type/flags to output section. We | |
167 | // use canonicalized strings here. | |
168 | ||
169 | typedef std::pair<const char*, | |
170 | std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key; | |
171 | ||
172 | struct Hash_key | |
173 | { | |
174 | size_t | |
175 | operator()(const Key& k) const; | |
176 | }; | |
177 | ||
178 | typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map; | |
179 | ||
180 | // A comparison class for segments. | |
181 | ||
182 | struct Compare_segments | |
183 | { | |
184 | bool | |
185 | operator()(const Output_segment* seg1, const Output_segment* seg2) | |
186 | { return Layout::segment_precedes(seg1, seg2); } | |
187 | }; | |
188 | ||
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189 | // A reference to the options on the command line. |
190 | const General_options& options_; | |
191 | // The output section names. | |
192 | Stringpool namepool_; | |
193 | // The list of group sections and linkonce sections which we have seen. | |
194 | Signatures signatures_; | |
195 | // The mapping from input section name/type/flags to output sections. | |
196 | Section_name_map section_name_map_; | |
197 | // The list of output segments. | |
198 | Segment_list segment_list_; | |
199 | // The list of output sections which are not attached to any output | |
200 | // segment. | |
201 | Section_list section_list_; | |
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202 | // The list of output data objects which are not attached to any |
203 | // output section or output segment. | |
204 | Data_list data_list_; | |
a2fb1b05 ILT |
205 | }; |
206 | ||
207 | } // End namespace gold. | |
208 | ||
209 | #endif // !defined(GOLD_LAYOUT_H) |