X-Git-Url: https://oss.titaniummirror.com/gitweb/?a=blobdiff_plain;f=gold%2Fgold.cc;fp=gold%2Fgold.cc;h=4ac1e3dca0388a22efc84801db073f0267f757b5;hb=d5da4f291af551c0b8b79e1d4a9b173d60e5c10e;hp=0000000000000000000000000000000000000000;hpb=7b5ea4fcdf2819e070665ab5610f8b48e3867c10;p=msp430-binutils.git diff --git a/gold/gold.cc b/gold/gold.cc new file mode 100644 index 0000000..4ac1e3d --- /dev/null +++ b/gold/gold.cc @@ -0,0 +1,640 @@ +// gold.cc -- main linker functions + +// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc. +// Written by Ian Lance Taylor . + +// This file is part of gold. + +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 3 of the License, or +// (at your option) any later version. + +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +// MA 02110-1301, USA. + +#include "gold.h" + +#include +#include +#include +#include +#include +#include "libiberty.h" + +#include "options.h" +#include "debug.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" +#include "plugin.h" +#include "gc.h" +#include "icf.h" +#include "incremental.h" + +namespace gold +{ + +const char* program_name; + +void +gold_exit(bool status) +{ + if (parameters != NULL + && parameters->options_valid() + && parameters->options().has_plugins()) + parameters->options().plugins()->cleanup(); + if (!status && parameters != NULL && parameters->options_valid()) + unlink_if_ordinary(parameters->options().output_file_name()); + exit(status ? EXIT_SUCCESS : EXIT_FAILURE); +} + +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. + + // LEN only exists to avoid a pointless warning when write is + // declared with warn_use_result, as when compiling with + // -D_USE_FORTIFY on GNU/Linux. Casting to void does not appear to + // work, at least not with gcc 4.3.0. + + ssize_t len = write(2, program_name, strlen(program_name)); + if (len >= 0) + { + const char* const s = ": out of memory\n"; + len = 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, Mapfile* mapfile) + : options_(options), input_objects_(input_objects), symtab_(symtab), + layout_(layout), mapfile_(mapfile) + { } + + void + run(Workqueue*, const Task*); + + private: + const General_options& options_; + const Input_objects* input_objects_; + Symbol_table* symtab_; + Layout* layout_; + Mapfile* mapfile_; +}; + +void +Middle_runner::run(Workqueue* workqueue, const Task* task) +{ + queue_middle_tasks(this->options_, task, this->input_objects_, this->symtab_, + this->layout_, workqueue, this->mapfile_); +} + +// This class arranges the tasks to process the relocs for garbage collection. + +class Gc_runner : public Task_function_runner +{ + public: + Gc_runner(const General_options& options, + const Input_objects* input_objects, + Symbol_table* symtab, + Layout* layout, Mapfile* mapfile) + : options_(options), input_objects_(input_objects), symtab_(symtab), + layout_(layout), mapfile_(mapfile) + { } + + void + run(Workqueue*, const Task*); + + private: + const General_options& options_; + const Input_objects* input_objects_; + Symbol_table* symtab_; + Layout* layout_; + Mapfile* mapfile_; +}; + +void +Gc_runner::run(Workqueue* workqueue, const Task* task) +{ + queue_middle_gc_tasks(this->options_, task, this->input_objects_, + this->symtab_, this->layout_, workqueue, + this->mapfile_); +} + +// Queue up the initial set of tasks for this link job. + +void +queue_initial_tasks(const General_options& options, + Dirsearch& search_path, + const Command_line& cmdline, + Workqueue* workqueue, Input_objects* input_objects, + Symbol_table* symtab, Layout* layout, Mapfile* mapfile) +{ + if (cmdline.begin() == cmdline.end()) + { + if (options.printed_version()) + gold_exit(true); + gold_fatal(_("no input files")); + } + + int thread_count = options.thread_count_initial(); + if (thread_count == 0) + thread_count = cmdline.number_of_input_files(); + workqueue->set_thread_count(thread_count); + + if (cmdline.options().incremental()) + { + Incremental_checker incremental_checker( + parameters->options().output_file_name(), + layout->incremental_inputs()); + if (incremental_checker.can_incrementally_link_output_file()) + { + // TODO: remove when incremental linking implemented. + printf("Incremental linking might be possible " + "(not implemented yet)\n"); + } + // TODO: If we decide on an incremental build, fewer tasks + // should be scheduled. + } + + // 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(true); + next_blocker->add_blocker(); + workqueue->queue(new Read_symbols(input_objects, symtab, layout, + &search_path, 0, mapfile, &*p, NULL, + this_blocker, next_blocker)); + this_blocker = next_blocker; + } + + if (options.has_plugins()) + { + Task_token* next_blocker = new Task_token(true); + next_blocker->add_blocker(); + workqueue->queue(new Plugin_hook(options, input_objects, symtab, layout, + &search_path, mapfile, this_blocker, + next_blocker)); + this_blocker = next_blocker; + } + + if (parameters->options().relocatable() + && (parameters->options().gc_sections() + || parameters->options().icf_enabled())) + gold_error(_("cannot mix -r with --gc-sections or --icf")); + + if (parameters->options().gc_sections() + || parameters->options().icf_enabled()) + { + workqueue->queue(new Task_function(new Gc_runner(options, + input_objects, + symtab, + layout, + mapfile), + this_blocker, + "Task_function Gc_runner")); + } + else + { + workqueue->queue(new Task_function(new Middle_runner(options, + input_objects, + symtab, + layout, + mapfile), + this_blocker, + "Task_function Middle_runner")); + } +} + +// Queue up a set of tasks to be done before queueing the middle set +// of tasks. This is only necessary when garbage collection +// (--gc-sections) of unused sections is desired. The relocs are read +// and processed here early to determine the garbage sections before the +// relocs can be scanned in later tasks. + +void +queue_middle_gc_tasks(const General_options& options, + const Task* , + const Input_objects* input_objects, + Symbol_table* symtab, + Layout* layout, + Workqueue* workqueue, + Mapfile* mapfile) +{ + // Read_relocs for all the objects must be done and processed to find + // unused sections before any scanning of the relocs can take place. + Task_token* blocker = new Task_token(true); + Task_token* symtab_lock = new Task_token(false); + 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. + blocker->add_blocker(); + workqueue->queue(new Read_relocs(options, symtab, layout, *p, + symtab_lock, blocker)); + } + + Task_token* this_blocker = new Task_token(true); + workqueue->queue(new Task_function(new Middle_runner(options, + input_objects, + symtab, + layout, + mapfile), + this_blocker, + "Task_function Middle_runner")); +} + +// 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 Task* task, + const Input_objects* input_objects, + Symbol_table* symtab, + Layout* layout, + Workqueue* workqueue, + Mapfile* mapfile) +{ + // Add any symbols named with -u options to the symbol table. + symtab->add_undefined_symbols_from_command_line(); + + // If garbage collection was chosen, relocs have been read and processed + // at this point by pre_middle_tasks. Layout can then be done for all + // objects. + if (parameters->options().gc_sections()) + { + // Find the start symbol if any. + Symbol* start_sym; + if (parameters->options().entry()) + start_sym = symtab->lookup(parameters->options().entry()); + else + start_sym = symtab->lookup("_start"); + if (start_sym !=NULL) + { + bool is_ordinary; + unsigned int shndx = start_sym->shndx(&is_ordinary); + if (is_ordinary) + { + symtab->gc()->worklist().push( + Section_id(start_sym->object(), shndx)); + } + } + // Symbols named with -u should not be considered garbage. + symtab->gc_mark_undef_symbols(); + gold_assert(symtab->gc() != NULL); + // Do a transitive closure on all references to determine the worklist. + symtab->gc()->do_transitive_closure(); + } + + // If identical code folding (--icf) is chosen it makes sense to do it + // only after garbage collection (--gc-sections) as we do not want to + // be folding sections that will be garbage. + if (parameters->options().icf_enabled()) + { + symtab->icf()->find_identical_sections(input_objects, symtab); + } + + // Call Object::layout for the second time to determine the + // output_sections for all referenced input sections. When + // --gc-sections or --icf is turned on, Object::layout is + // called twice. It is called the first time when the + // symbols are added. + if (parameters->options().gc_sections() + || parameters->options().icf_enabled()) + { + for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); + p != input_objects->relobj_end(); + ++p) + { + (*p)->layout(symtab, layout, NULL); + } + } + + // Layout deferred objects due to plugins. + if (parameters->options().has_plugins()) + { + Plugin_manager* plugins = parameters->options().plugins(); + gold_assert(plugins != NULL); + plugins->layout_deferred_objects(); + } + + if (parameters->options().gc_sections() + || parameters->options().icf_enabled()) + { + for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); + p != input_objects->relobj_end(); + ++p) + { + // Update the value of output_section stored in rd. + Read_relocs_data *rd = (*p)->get_relocs_data(); + for (Read_relocs_data::Relocs_list::iterator q = rd->relocs.begin(); + q != rd->relocs.end(); + ++q) + { + q->output_section = (*p)->output_section(q->data_shndx); + q->needs_special_offset_handling = + (*p)->is_output_section_offset_invalid(q->data_shndx); + } + } + } + + // We have to support the case of not seeing any input objects, and + // generate an empty file. Existing builds depend on being able to + // pass an empty archive to the linker and get an empty object file + // out. In order to do this we need to use a default target. + if (input_objects->number_of_input_objects() == 0) + parameters_force_valid_target(); + + int thread_count = options.thread_count_middle(); + if (thread_count == 0) + thread_count = std::max(2, input_objects->number_of_input_objects()); + workqueue->set_thread_count(thread_count); + + // Now we have seen all the input files. + const bool doing_static_link = + (!input_objects->any_dynamic() + && !parameters->options().output_is_position_independent()); + set_parameters_doing_static_link(doing_static_link); + if (!doing_static_link && options.is_static()) + { + // We print out just the first .so we see; there may be others. + gold_assert(input_objects->dynobj_begin() != input_objects->dynobj_end()); + gold_error(_("cannot mix -static with dynamic object %s"), + (*input_objects->dynobj_begin())->name().c_str()); + } + if (!doing_static_link && parameters->options().relocatable()) + gold_fatal(_("cannot mix -r with dynamic object %s"), + (*input_objects->dynobj_begin())->name().c_str()); + if (!doing_static_link + && options.oformat_enum() != General_options::OBJECT_FORMAT_ELF) + gold_fatal(_("cannot use non-ELF output format with dynamic object %s"), + (*input_objects->dynobj_begin())->name().c_str()); + + if (parameters->options().relocatable()) + { + Input_objects::Relobj_iterator p = input_objects->relobj_begin(); + if (p != input_objects->relobj_end()) + { + bool uses_split_stack = (*p)->uses_split_stack(); + for (++p; p != input_objects->relobj_end(); ++p) + { + if ((*p)->uses_split_stack() != uses_split_stack) + gold_fatal(_("cannot mix split-stack '%s' and " + "non-split-stack '%s' when using -r"), + (*input_objects->relobj_begin())->name().c_str(), + (*p)->name().c_str()); + } + } + } + + if (is_debugging_enabled(DEBUG_SCRIPT)) + layout->script_options()->print(stderr); + + // For each dynamic object, record whether we've seen all the + // dynamic objects that it depends upon. + input_objects->check_dynamic_dependencies(); + + // See if any of the input definitions violate the One Definition Rule. + // TODO: if this is too slow, do this as a task, rather than inline. + symtab->detect_odr_violations(task, options.output_file_name()); + + // Create any automatic note sections. + layout->create_notes(); + + // Create any output sections required by any linker script. + layout->create_script_sections(); + + // 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(symtab); + + // Define symbols from any linker scripts. + layout->define_script_symbols(symtab); + + // Attach sections to segments. + layout->attach_sections_to_segments(); + + if (!parameters->options().relocatable()) + { + // Predefine standard symbols. + define_standard_symbols(symtab, layout); + + // Define __start and __stop symbols for output sections where + // appropriate. + layout->define_section_symbols(symtab); + } + + // Make sure we have symbols for any required group signatures. + layout->define_group_signatures(symtab); + + Task_token* blocker = new Task_token(true); + Task_token* symtab_lock = new Task_token(false); + + // If doing garbage collection, the relocations have already been read. + // Otherwise, read and scan the relocations. + if (parameters->options().gc_sections() + || parameters->options().icf_enabled()) + { + for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); + p != input_objects->relobj_end(); + ++p) + { + blocker->add_blocker(); + workqueue->queue(new Scan_relocs(options, symtab, layout, *p, + (*p)->get_relocs_data(),symtab_lock, blocker)); + } + } + else + { + // 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. + 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. + if (parameters->options().define_common()) + { + blocker->add_blocker(); + workqueue->queue(new Allocate_commons_task(symtab, layout, mapfile, + symtab_lock, blocker)); + } + + // When all those tasks are complete, we can start laying out the + // output file. + // TODO(csilvers): figure out a more principled way to get the target + Target* target = const_cast(¶meters->target()); + workqueue->queue(new Task_function(new Layout_task_runner(options, + input_objects, + symtab, + target, + layout, + mapfile), + blocker, + "Task_function Layout_task_runner")); +} + +// 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, + Layout* layout, + Workqueue* workqueue, + Output_file* of) +{ + int thread_count = options.thread_count_final(); + if (thread_count == 0) + thread_count = std::max(2, input_objects->number_of_input_objects()); + workqueue->set_thread_count(thread_count); + + bool any_postprocessing_sections = layout->any_postprocessing_sections(); + + // Use a blocker to wait until all the input sections have been + // written out. + Task_token* input_sections_blocker = NULL; + if (!any_postprocessing_sections) + input_sections_blocker = new Task_token(true); + + // Use a blocker to block any objects which have to wait for the + // output sections to complete before they can apply relocations. + Task_token* output_sections_blocker = new Task_token(true); + + // Use a blocker to block the final cleanup task. + Task_token* final_blocker = new Task_token(true); + + // Queue a task to write out the symbol table. + final_blocker->add_blocker(); + workqueue->queue(new Write_symbols_task(layout, + symtab, + input_objects, + layout->sympool(), + layout->dynpool(), + of, + final_blocker)); + + // Queue a task to write out the output sections. + output_sections_blocker->add_blocker(); + final_blocker->add_blocker(); + workqueue->queue(new Write_sections_task(layout, of, output_sections_blocker, + final_blocker)); + + // Queue a task to write out everything else. + final_blocker->add_blocker(); + workqueue->queue(new Write_data_task(layout, symtab, of, final_blocker)); + + // 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) + { + if (input_sections_blocker != NULL) + input_sections_blocker->add_blocker(); + final_blocker->add_blocker(); + workqueue->queue(new Relocate_task(options, symtab, layout, *p, of, + input_sections_blocker, + output_sections_blocker, + final_blocker)); + } + + // Queue a task to write out the output sections which depend on + // input sections. If there are any sections which require + // postprocessing, then we need to do this last, since it may resize + // the output file. + if (!any_postprocessing_sections) + { + final_blocker->add_blocker(); + Task* t = new Write_after_input_sections_task(layout, of, + input_sections_blocker, + final_blocker); + workqueue->queue(t); + } + else + { + Task_token *new_final_blocker = new Task_token(true); + new_final_blocker->add_blocker(); + Task* t = new Write_after_input_sections_task(layout, of, + final_blocker, + new_final_blocker); + workqueue->queue(t); + final_blocker = new_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(&options, layout, + of), + final_blocker, + "Task_function Close_task_runner")); +} + +} // End namespace gold.