2007-07-26 Michael Snyder <msnyder@access-company.com>
[binutils.git] / gold / gold.cc
blobe7b7ae2939d7d470c5d6506a68eae7c1ab3dd217
1 // gold.cc -- main linker functions
3 #include "gold.h"
5 #include <cstdlib>
6 #include <cstdio>
7 #include <cstring>
8 #include <unistd.h>
10 #include "options.h"
11 #include "workqueue.h"
12 #include "dirsearch.h"
13 #include "readsyms.h"
14 #include "symtab.h"
15 #include "common.h"
16 #include "object.h"
17 #include "layout.h"
18 #include "reloc.h"
19 #include "defstd.h"
21 namespace gold
24 const char* program_name;
26 void
27 gold_exit(bool status)
29 exit(status ? EXIT_SUCCESS : EXIT_FAILURE);
32 void
33 gold_fatal(const char* msg, bool perrno)
35 fprintf(stderr, "%s: ", program_name);
36 if (perrno)
37 perror(msg);
38 else
39 fprintf(stderr, "%s\n", msg);
40 gold_exit(false);
43 void
44 gold_nomem()
46 // We are out of memory, so try hard to print a reasonable message.
47 // Note that we don't try to translate this message, since the
48 // translation process itself will require memory.
49 write(2, program_name, strlen(program_name));
50 const char* const s = ": out of memory\n";
51 write(2, s, strlen(s));
52 gold_exit(false);
55 // Handle an unreachable case.
57 void
58 do_gold_unreachable(const char* filename, int lineno, const char* function)
60 fprintf(stderr, "%s: internal error in %s, at %s:%d\n",
61 program_name, function, filename, lineno);
62 gold_exit(false);
65 // This class arranges to run the functions done in the middle of the
66 // link. It is just a closure.
68 class Middle_runner : public Task_function_runner
70 public:
71 Middle_runner(const General_options& options,
72 const Input_objects* input_objects,
73 Symbol_table* symtab,
74 Layout* layout)
75 : options_(options), input_objects_(input_objects), symtab_(symtab),
76 layout_(layout)
77 { }
79 void
80 run(Workqueue*);
82 private:
83 const General_options& options_;
84 const Input_objects* input_objects_;
85 Symbol_table* symtab_;
86 Layout* layout_;
89 void
90 Middle_runner::run(Workqueue* workqueue)
92 queue_middle_tasks(this->options_, this->input_objects_, this->symtab_,
93 this->layout_, workqueue);
96 // Queue up the initial set of tasks for this link job.
98 void
99 queue_initial_tasks(const General_options& options,
100 const Dirsearch& search_path,
101 const Command_line& cmdline,
102 Workqueue* workqueue, Input_objects* input_objects,
103 Symbol_table* symtab, Layout* layout)
105 if (cmdline.begin() == cmdline.end())
106 gold_fatal(_("no input files"), false);
108 // Read the input files. We have to add the symbols to the symbol
109 // table in order. We do this by creating a separate blocker for
110 // each input file. We associate the blocker with the following
111 // input file, to give us a convenient place to delete it.
112 Task_token* this_blocker = NULL;
113 for (Command_line::const_iterator p = cmdline.begin();
114 p != cmdline.end();
115 ++p)
117 Task_token* next_blocker = new Task_token();
118 next_blocker->add_blocker();
119 workqueue->queue(new Read_symbols(options, input_objects, symtab, layout,
120 search_path, &*p, NULL, this_blocker,
121 next_blocker));
122 this_blocker = next_blocker;
125 workqueue->queue(new Task_function(new Middle_runner(options,
126 input_objects,
127 symtab,
128 layout),
129 this_blocker));
132 // Queue up the middle set of tasks. These are the tasks which run
133 // after all the input objects have been found and all the symbols
134 // have been read, but before we lay out the output file.
136 void
137 queue_middle_tasks(const General_options& options,
138 const Input_objects* input_objects,
139 Symbol_table* symtab,
140 Layout* layout,
141 Workqueue* workqueue)
143 // Define some sections and symbols needed for a dynamic link. This
144 // handles some cases we want to see before we read the relocs.
145 layout->create_initial_dynamic_sections(input_objects, symtab);
147 // Predefine standard symbols. This should be fast, so we don't
148 // bother to create a task for it.
149 define_standard_symbols(symtab, layout, input_objects->target());
151 // Read the relocations of the input files. We do this to find
152 // which symbols are used by relocations which require a GOT and/or
153 // a PLT entry, or a COPY reloc. When we implement garbage
154 // collection we will do it here by reading the relocations in a
155 // breadth first search by references.
157 // We could also read the relocations during the first pass, and
158 // mark symbols at that time. That is how the old GNU linker works.
159 // Doing that is more complex, since we may later decide to discard
160 // some of the sections, and thus change our minds about the types
161 // of references made to the symbols.
162 Task_token* blocker = new Task_token();
163 Task_token* symtab_lock = new Task_token();
164 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
165 p != input_objects->relobj_end();
166 ++p)
168 // We can read and process the relocations in any order. But we
169 // only want one task to write to the symbol table at a time.
170 // So we queue up a task for each object to read the
171 // relocations. That task will in turn queue a task to wait
172 // until it can write to the symbol table.
173 blocker->add_blocker();
174 workqueue->queue(new Read_relocs(options, symtab, layout, *p,
175 symtab_lock, blocker));
178 // Allocate common symbols. This requires write access to the
179 // symbol table, but is independent of the relocation processing.
180 blocker->add_blocker();
181 workqueue->queue(new Allocate_commons_task(options, symtab, layout,
182 symtab_lock, blocker));
184 // When all those tasks are complete, we can start laying out the
185 // output file.
186 workqueue->queue(new Task_function(new Layout_task_runner(options,
187 input_objects,
188 symtab,
189 layout),
190 blocker));
193 // Queue up the final set of tasks. This is called at the end of
194 // Layout_task.
196 void
197 queue_final_tasks(const General_options& options,
198 const Input_objects* input_objects,
199 const Symbol_table* symtab,
200 const Layout* layout,
201 Workqueue* workqueue,
202 Output_file* of)
204 // Use a blocker to block the final cleanup task.
205 Task_token* final_blocker = new Task_token();
207 // Queue a task for each input object to relocate the sections and
208 // write out the local symbols.
209 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
210 p != input_objects->relobj_end();
211 ++p)
213 final_blocker->add_blocker();
214 workqueue->queue(new Relocate_task(options, symtab, layout, *p, of,
215 final_blocker));
218 // Queue a task to write out the symbol table.
219 final_blocker->add_blocker();
220 workqueue->queue(new Write_symbols_task(symtab,
221 input_objects->target(),
222 layout->sympool(),
223 layout->dynpool(),
225 final_blocker));
227 // Queue a task to write out everything else.
228 final_blocker->add_blocker();
229 workqueue->queue(new Write_data_task(layout, symtab,
230 input_objects->target(),
231 of, final_blocker));
233 // Queue a task to close the output file. This will be blocked by
234 // FINAL_BLOCKER.
235 workqueue->queue(new Task_function(new Close_task_runner(of),
236 final_blocker));
239 } // End namespace gold.