// gold.cc -- main linker functions #include "gold.h" #include <cstdlib> #include <cstdio> #include <cstring> #include <unistd.h> #include "options.h" #include "workqueue.h" #include "dirsearch.h" #include "readsyms.h" #include "symtab.h" #include "common.h" #include "object.h" #include "layout.h" #include "reloc.h" #include "defstd.h" namespace gold { const char* program_name; void gold_exit(bool status) { exit(status ? EXIT_SUCCESS : EXIT_FAILURE); } void gold_fatal(const char* msg, bool perrno) { fprintf(stderr, "%s: ", program_name); if (perrno) perror(msg); else fprintf(stderr, "%s\n", msg); gold_exit(false); } void gold_nomem() { // We are out of memory, so try hard to print a reasonable message. // Note that we don't try to translate this message, since the // translation process itself will require memory. write(2, program_name, strlen(program_name)); const char* const s = ": out of memory\n"; write(2, s, strlen(s)); gold_exit(false); } // Handle an unreachable case. void do_gold_unreachable(const char* filename, int lineno, const char* function) { fprintf(stderr, "%s: internal error in %s, at %s:%d\n", program_name, function, filename, lineno); gold_exit(false); } // This class arranges to run the functions done in the middle of the // link. It is just a closure. class Middle_runner : public Task_function_runner { public: Middle_runner(const General_options& options, const Input_objects* input_objects, Symbol_table* symtab, Layout* layout) : options_(options), input_objects_(input_objects), symtab_(symtab), layout_(layout) { } void run(Workqueue*); private: const General_options& options_; const Input_objects* input_objects_; Symbol_table* symtab_; Layout* layout_; }; void Middle_runner::run(Workqueue* workqueue) { queue_middle_tasks(this->options_, this->input_objects_, this->symtab_, this->layout_, workqueue); } // Queue up the initial set of tasks for this link job. void queue_initial_tasks(const General_options& options, const Dirsearch& search_path, const Command_line& cmdline, Workqueue* workqueue, Input_objects* input_objects, Symbol_table* symtab, Layout* layout) { if (cmdline.begin() == cmdline.end()) gold_fatal(_("no input files"), false); // Read the input files. We have to add the symbols to the symbol // table in order. We do this by creating a separate blocker for // each input file. We associate the blocker with the following // input file, to give us a convenient place to delete it. Task_token* this_blocker = NULL; for (Command_line::const_iterator p = cmdline.begin(); p != cmdline.end(); ++p) { Task_token* next_blocker = new Task_token(); next_blocker->add_blocker(); workqueue->queue(new Read_symbols(options, input_objects, symtab, layout, search_path, &*p, NULL, this_blocker, next_blocker)); this_blocker = next_blocker; } workqueue->queue(new Task_function(new Middle_runner(options, input_objects, symtab, layout), this_blocker)); } // Queue up the middle set of tasks. These are the tasks which run // after all the input objects have been found and all the symbols // have been read, but before we lay out the output file. void queue_middle_tasks(const General_options& options, const Input_objects* input_objects, Symbol_table* symtab, Layout* layout, Workqueue* workqueue) { // Define some sections and symbols needed for a dynamic link. This // handles some cases we want to see before we read the relocs. layout->create_initial_dynamic_sections(input_objects, symtab); // Predefine standard symbols. This should be fast, so we don't // bother to create a task for it. define_standard_symbols(symtab, layout, input_objects->target()); // Read the relocations of the input files. We do this to find // which symbols are used by relocations which require a GOT and/or // a PLT entry, or a COPY reloc. When we implement garbage // collection we will do it here by reading the relocations in a // breadth first search by references. // // We could also read the relocations during the first pass, and // mark symbols at that time. That is how the old GNU linker works. // Doing that is more complex, since we may later decide to discard // some of the sections, and thus change our minds about the types // of references made to the symbols. Task_token* blocker = new Task_token(); Task_token* symtab_lock = new Task_token(); for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); p != input_objects->relobj_end(); ++p) { // We can read and process the relocations in any order. But we // only want one task to write to the symbol table at a time. // So we queue up a task for each object to read the // relocations. That task will in turn queue a task to wait // until it can write to the symbol table. blocker->add_blocker(); workqueue->queue(new Read_relocs(options, symtab, layout, *p, symtab_lock, blocker)); } // Allocate common symbols. This requires write access to the // symbol table, but is independent of the relocation processing. blocker->add_blocker(); workqueue->queue(new Allocate_commons_task(options, symtab, layout, symtab_lock, blocker)); // When all those tasks are complete, we can start laying out the // output file. workqueue->queue(new Task_function(new Layout_task_runner(options, input_objects, symtab, layout), blocker)); } // Queue up the final set of tasks. This is called at the end of // Layout_task. void queue_final_tasks(const General_options& options, const Input_objects* input_objects, const Symbol_table* symtab, const Layout* layout, Workqueue* workqueue, Output_file* of) { // Use a blocker to block the final cleanup task. Task_token* final_blocker = new Task_token(); // Queue a task for each input object to relocate the sections and // write out the local symbols. for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); p != input_objects->relobj_end(); ++p) { final_blocker->add_blocker(); workqueue->queue(new Relocate_task(options, symtab, layout, *p, of, final_blocker)); } // Queue a task to write out the symbol table. final_blocker->add_blocker(); workqueue->queue(new Write_symbols_task(symtab, input_objects->target(), layout->sympool(), layout->dynpool(), of, final_blocker)); // Queue a task to write out everything else. final_blocker->add_blocker(); workqueue->queue(new Write_data_task(layout, symtab, input_objects->target(), of, final_blocker)); // Queue a task to close the output file. This will be blocked by // FINAL_BLOCKER. workqueue->queue(new Task_function(new Close_task_runner(of), final_blocker)); } } // End namespace gold.