--- /dev/null
+// gold.cc -- main linker functions
+
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@google.com>.
+
+// 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 <cstdlib>
+#include <cstdio>
+#include <cstring>
+#include <unistd.h>
+#include <algorithm>
+#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<Target*>(¶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.
projects / msp430-binutils.git / blobdiff