X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Flayout.cc;h=c9ea9ebed477d6315de6f6013f75f28d15dabdfa;hb=128e85e3ab36b8e30f6612fb50de3cbb4ede6824;hp=be4bb5ccde18d0854df5f8cf1d0c7fab4f43f307;hpb=f625ae503e5bf88c2f5d6b5a34316416f1fd0f9b;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/layout.cc b/gold/layout.cc index be4bb5ccde..c9ea9ebed4 100644 --- a/gold/layout.cc +++ b/gold/layout.cc @@ -1,6 +1,6 @@ // layout.cc -- lay out output file sections for gold -// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. +// Copyright (C) 2006-2016 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -34,6 +34,10 @@ #include "libiberty.h" #include "md5.h" #include "sha1.h" +#ifdef __MINGW32__ +#include +#include +#endif #include "parameters.h" #include "options.h" @@ -44,8 +48,10 @@ #include "symtab.h" #include "dynobj.h" #include "ehframe.h" +#include "gdb-index.h" #include "compressed_output.h" #include "reduced_debug_output.h" +#include "object.h" #include "reloc.h" #include "descriptors.h" #include "plugin.h" @@ -55,6 +61,228 @@ namespace gold { +// Class Free_list. + +// The total number of free lists used. +unsigned int Free_list::num_lists = 0; +// The total number of free list nodes used. +unsigned int Free_list::num_nodes = 0; +// The total number of calls to Free_list::remove. +unsigned int Free_list::num_removes = 0; +// The total number of nodes visited during calls to Free_list::remove. +unsigned int Free_list::num_remove_visits = 0; +// The total number of calls to Free_list::allocate. +unsigned int Free_list::num_allocates = 0; +// The total number of nodes visited during calls to Free_list::allocate. +unsigned int Free_list::num_allocate_visits = 0; + +// Initialize the free list. Creates a single free list node that +// describes the entire region of length LEN. If EXTEND is true, +// allocate() is allowed to extend the region beyond its initial +// length. + +void +Free_list::init(off_t len, bool extend) +{ + this->list_.push_front(Free_list_node(0, len)); + this->last_remove_ = this->list_.begin(); + this->extend_ = extend; + this->length_ = len; + ++Free_list::num_lists; + ++Free_list::num_nodes; +} + +// Remove a chunk from the free list. Because we start with a single +// node that covers the entire section, and remove chunks from it one +// at a time, we do not need to coalesce chunks or handle cases that +// span more than one free node. We expect to remove chunks from the +// free list in order, and we expect to have only a few chunks of free +// space left (corresponding to files that have changed since the last +// incremental link), so a simple linear list should provide sufficient +// performance. + +void +Free_list::remove(off_t start, off_t end) +{ + if (start == end) + return; + gold_assert(start < end); + + ++Free_list::num_removes; + + Iterator p = this->last_remove_; + if (p->start_ > start) + p = this->list_.begin(); + + for (; p != this->list_.end(); ++p) + { + ++Free_list::num_remove_visits; + // Find a node that wholly contains the indicated region. + if (p->start_ <= start && p->end_ >= end) + { + // Case 1: the indicated region spans the whole node. + // Add some fuzz to avoid creating tiny free chunks. + if (p->start_ + 3 >= start && p->end_ <= end + 3) + p = this->list_.erase(p); + // Case 2: remove a chunk from the start of the node. + else if (p->start_ + 3 >= start) + p->start_ = end; + // Case 3: remove a chunk from the end of the node. + else if (p->end_ <= end + 3) + p->end_ = start; + // Case 4: remove a chunk from the middle, and split + // the node into two. + else + { + Free_list_node newnode(p->start_, start); + p->start_ = end; + this->list_.insert(p, newnode); + ++Free_list::num_nodes; + } + this->last_remove_ = p; + return; + } + } + + // Did not find a node containing the given chunk. This could happen + // because a small chunk was already removed due to the fuzz. + gold_debug(DEBUG_INCREMENTAL, + "Free_list::remove(%d,%d) not found", + static_cast(start), static_cast(end)); +} + +// Allocate a chunk of size LEN from the free list. Returns -1ULL +// if a sufficiently large chunk of free space is not found. +// We use a simple first-fit algorithm. + +off_t +Free_list::allocate(off_t len, uint64_t align, off_t minoff) +{ + gold_debug(DEBUG_INCREMENTAL, + "Free_list::allocate(%08lx, %d, %08lx)", + static_cast(len), static_cast(align), + static_cast(minoff)); + if (len == 0) + return align_address(minoff, align); + + ++Free_list::num_allocates; + + // We usually want to drop free chunks smaller than 4 bytes. + // If we need to guarantee a minimum hole size, though, we need + // to keep track of all free chunks. + const int fuzz = this->min_hole_ > 0 ? 0 : 3; + + for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p) + { + ++Free_list::num_allocate_visits; + off_t start = p->start_ > minoff ? p->start_ : minoff; + start = align_address(start, align); + off_t end = start + len; + if (end > p->end_ && p->end_ == this->length_ && this->extend_) + { + this->length_ = end; + p->end_ = end; + } + if (end == p->end_ || (end <= p->end_ - this->min_hole_)) + { + if (p->start_ + fuzz >= start && p->end_ <= end + fuzz) + this->list_.erase(p); + else if (p->start_ + fuzz >= start) + p->start_ = end; + else if (p->end_ <= end + fuzz) + p->end_ = start; + else + { + Free_list_node newnode(p->start_, start); + p->start_ = end; + this->list_.insert(p, newnode); + ++Free_list::num_nodes; + } + return start; + } + } + if (this->extend_) + { + off_t start = align_address(this->length_, align); + this->length_ = start + len; + return start; + } + return -1; +} + +// Dump the free list (for debugging). +void +Free_list::dump() +{ + gold_info("Free list:\n start end length\n"); + for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p) + gold_info(" %08lx %08lx %08lx", static_cast(p->start_), + static_cast(p->end_), + static_cast(p->end_ - p->start_)); +} + +// Print the statistics for the free lists. +void +Free_list::print_stats() +{ + fprintf(stderr, _("%s: total free lists: %u\n"), + program_name, Free_list::num_lists); + fprintf(stderr, _("%s: total free list nodes: %u\n"), + program_name, Free_list::num_nodes); + fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"), + program_name, Free_list::num_removes); + fprintf(stderr, _("%s: nodes visited: %u\n"), + program_name, Free_list::num_remove_visits); + fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"), + program_name, Free_list::num_allocates); + fprintf(stderr, _("%s: nodes visited: %u\n"), + program_name, Free_list::num_allocate_visits); +} + +// A Hash_task computes the MD5 checksum of an array of char. + +class Hash_task : public Task +{ + public: + Hash_task(Output_file* of, + size_t offset, + size_t size, + unsigned char* dst, + Task_token* final_blocker) + : of_(of), offset_(offset), size_(size), dst_(dst), + final_blocker_(final_blocker) + { } + + void + run(Workqueue*) + { + const unsigned char* iv = + this->of_->get_input_view(this->offset_, this->size_); + md5_buffer(reinterpret_cast(iv), this->size_, this->dst_); + this->of_->free_input_view(this->offset_, this->size_, iv); + } + + Task_token* + is_runnable() + { return NULL; } + + // Unblock FINAL_BLOCKER_ when done. + void + locks(Task_locker* tl) + { tl->add(this, this->final_blocker_); } + + std::string + get_name() const + { return "Hash_task"; } + + private: + Output_file* of_; + const size_t offset_; + const size_t size_; + unsigned char* const dst_; + Task_token* const final_blocker_; +}; + // Layout::Relaxation_debug_check methods. // Check that sections and special data are in reset states. @@ -64,7 +292,8 @@ namespace gold void Layout::Relaxation_debug_check::check_output_data_for_reset_values( const Layout::Section_list& sections, - const Layout::Data_list& special_outputs) + const Layout::Data_list& special_outputs, + const Layout::Data_list& relax_outputs) { for(Layout::Section_list::const_iterator p = sections.begin(); p != sections.end(); @@ -75,8 +304,10 @@ Layout::Relaxation_debug_check::check_output_data_for_reset_values( p != special_outputs.end(); ++p) gold_assert((*p)->address_and_file_offset_have_reset_values()); + + gold_assert(relax_outputs.empty()); } - + // Save information of SECTIONS for checking later. void @@ -136,10 +367,15 @@ Layout::Relaxation_debug_check::verify_sections( void Layout_task_runner::run(Workqueue* workqueue, const Task* task) { - off_t file_size = this->layout_->finalize(this->input_objects_, - this->symtab_, - this->target_, - task); + // 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. + this->symtab_->detect_odr_violations(task, this->options_.output_file_name()); + + Layout* layout = this->layout_; + off_t file_size = layout->finalize(this->input_objects_, + this->symtab_, + this->target_, + task); // Now we know the final size of the output file and we know where // each piece of information goes. @@ -147,17 +383,37 @@ Layout_task_runner::run(Workqueue* workqueue, const Task* task) if (this->mapfile_ != NULL) { this->mapfile_->print_discarded_sections(this->input_objects_); - this->layout_->print_to_mapfile(this->mapfile_); + layout->print_to_mapfile(this->mapfile_); } - Output_file* of = new Output_file(parameters->options().output_file_name()); - if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF) - of->set_is_temporary(); - of->open(file_size); + Output_file* of; + if (layout->incremental_base() == NULL) + { + of = new Output_file(parameters->options().output_file_name()); + if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF) + of->set_is_temporary(); + of->open(file_size); + } + else + { + of = layout->incremental_base()->output_file(); + + // Apply the incremental relocations for symbols whose values + // have changed. We do this before we resize the file and start + // writing anything else to it, so that we can read the old + // incremental information from the file before (possibly) + // overwriting it. + if (parameters->incremental_update()) + layout->incremental_base()->apply_incremental_relocs(this->symtab_, + this->layout_, + of); + + of->resize(file_size); + } // Queue up the final set of tasks. gold::queue_final_tasks(this->options_, this->input_objects_, - this->symtab_, this->layout_, workqueue, of); + this->symtab_, layout, workqueue, of); } // Layout methods. @@ -174,9 +430,11 @@ Layout::Layout(int number_of_input_files, Script_options* script_options) section_list_(), unattached_section_list_(), special_output_list_(), + relax_output_list_(), section_headers_(NULL), tls_segment_(NULL), relro_segment_(NULL), + interp_segment_(NULL), increase_relro_(0), symtab_section_(NULL), symtab_xindex_(NULL), @@ -189,6 +447,7 @@ Layout::Layout(int number_of_input_files, Script_options* script_options) eh_frame_data_(NULL), added_eh_frame_data_(false), eh_frame_hdr_section_(NULL), + gdb_index_data_(NULL), build_id_note_(NULL), debug_abbrev_(NULL), debug_info_(NULL), @@ -203,11 +462,19 @@ Layout::Layout(int number_of_input_files, Script_options* script_options) any_postprocessing_sections_(false), resized_signatures_(false), have_stabstr_section_(false), + section_ordering_specified_(false), + unique_segment_for_sections_specified_(false), incremental_inputs_(NULL), record_output_section_data_from_script_(false), script_output_section_data_list_(), segment_states_(NULL), - relaxation_debug_check_(NULL) + relaxation_debug_check_(NULL), + section_order_map_(), + section_segment_map_(), + input_section_position_(), + input_section_glob_(), + incremental_base_(NULL), + free_list_() { // Make space for more than enough segments for a typical file. // This is just for efficiency--it's OK if we wind up needing more. @@ -226,6 +493,15 @@ Layout::Layout(int number_of_input_files, Script_options* script_options) this->namepool_.set_optimize(); } +// For incremental links, record the base file to be modified. + +void +Layout::set_incremental_base(Incremental_binary* base) +{ + this->incremental_base_ = base; + this->free_list_.init(base->output_file()->filesize(), true); +} + // Hash a key we use to look up an output section mapping. size_t @@ -234,71 +510,163 @@ Layout::Hash_key::operator()(const Layout::Key& k) const return k.first + k.second.first + k.second.second; } -// Returns whether the given section is in the list of -// debug-sections-used-by-some-version-of-gdb. Currently, -// we've checked versions of gdb up to and including 6.7.1. +// These are the debug sections that are actually used by gdb. +// Currently, we've checked versions of gdb up to and including 7.4. +// We only check the part of the name that follows ".debug_" or +// ".zdebug_". static const char* gdb_sections[] = -{ ".debug_abbrev", - // ".debug_aranges", // not used by gdb as of 6.7.1 - ".debug_frame", - ".debug_info", - ".debug_types", - ".debug_line", - ".debug_loc", - ".debug_macinfo", - // ".debug_pubnames", // not used by gdb as of 6.7.1 - ".debug_ranges", - ".debug_str", +{ + "abbrev", + "addr", // Fission extension + // "aranges", // not used by gdb as of 7.4 + "frame", + "gdb_scripts", + "info", + "types", + "line", + "loc", + "macinfo", + "macro", + // "pubnames", // not used by gdb as of 7.4 + // "pubtypes", // not used by gdb as of 7.4 + // "gnu_pubnames", // Fission extension + // "gnu_pubtypes", // Fission extension + "ranges", + "str", + "str_offsets", }; +// This is the minimum set of sections needed for line numbers. + static const char* lines_only_debug_sections[] = -{ ".debug_abbrev", - // ".debug_aranges", // not used by gdb as of 6.7.1 - // ".debug_frame", - ".debug_info", - // ".debug_types", - ".debug_line", - // ".debug_loc", - // ".debug_macinfo", - // ".debug_pubnames", // not used by gdb as of 6.7.1 - // ".debug_ranges", - ".debug_str", +{ + "abbrev", + // "addr", // Fission extension + // "aranges", // not used by gdb as of 7.4 + // "frame", + // "gdb_scripts", + "info", + // "types", + "line", + // "loc", + // "macinfo", + // "macro", + // "pubnames", // not used by gdb as of 7.4 + // "pubtypes", // not used by gdb as of 7.4 + // "gnu_pubnames", // Fission extension + // "gnu_pubtypes", // Fission extension + // "ranges", + "str", + "str_offsets", // Fission extension }; +// These sections are the DWARF fast-lookup tables, and are not needed +// when building a .gdb_index section. + +static const char* gdb_fast_lookup_sections[] = +{ + "aranges", + "pubnames", + "gnu_pubnames", + "pubtypes", + "gnu_pubtypes", +}; + +// Returns whether the given debug section is in the list of +// debug-sections-used-by-some-version-of-gdb. SUFFIX is the +// portion of the name following ".debug_" or ".zdebug_". + static inline bool -is_gdb_debug_section(const char* str) +is_gdb_debug_section(const char* suffix) { // We can do this faster: binary search or a hashtable. But why bother? for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i) - if (strcmp(str, gdb_sections[i]) == 0) + if (strcmp(suffix, gdb_sections[i]) == 0) return true; return false; } +// Returns whether the given section is needed for lines-only debugging. + static inline bool -is_lines_only_debug_section(const char* str) +is_lines_only_debug_section(const char* suffix) { // We can do this faster: binary search or a hashtable. But why bother? for (size_t i = 0; i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections); ++i) - if (strcmp(str, lines_only_debug_sections[i]) == 0) + if (strcmp(suffix, lines_only_debug_sections[i]) == 0) + return true; + return false; +} + +// Returns whether the given section is a fast-lookup section that +// will not be needed when building a .gdb_index section. + +static inline bool +is_gdb_fast_lookup_section(const char* suffix) +{ + // We can do this faster: binary search or a hashtable. But why bother? + for (size_t i = 0; + i < sizeof(gdb_fast_lookup_sections)/sizeof(*gdb_fast_lookup_sections); + ++i) + if (strcmp(suffix, gdb_fast_lookup_sections[i]) == 0) return true; return false; } +// Sometimes we compress sections. This is typically done for +// sections that are not part of normal program execution (such as +// .debug_* sections), and where the readers of these sections know +// how to deal with compressed sections. This routine doesn't say for +// certain whether we'll compress -- it depends on commandline options +// as well -- just whether this section is a candidate for compression. +// (The Output_compressed_section class decides whether to compress +// a given section, and picks the name of the compressed section.) + +static bool +is_compressible_debug_section(const char* secname) +{ + return (is_prefix_of(".debug", secname)); +} + +// We may see compressed debug sections in input files. Return TRUE +// if this is the name of a compressed debug section. + +bool +is_compressed_debug_section(const char* secname) +{ + return (is_prefix_of(".zdebug", secname)); +} + +std::string +corresponding_uncompressed_section_name(std::string secname) +{ + gold_assert(secname[0] == '.' && secname[1] == 'z'); + std::string ret("."); + ret.append(secname, 2, std::string::npos); + return ret; +} + // Whether to include this section in the link. template bool -Layout::include_section(Sized_relobj*, const char* name, +Layout::include_section(Sized_relobj_file*, const char* name, const elfcpp::Shdr& shdr) { - if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE) + if (!parameters->options().relocatable() + && (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)) return false; - switch (shdr.get_sh_type()) + elfcpp::Elf_Word sh_type = shdr.get_sh_type(); + + if ((sh_type >= elfcpp::SHT_LOOS && sh_type <= elfcpp::SHT_HIOS) + || (sh_type >= elfcpp::SHT_LOPROC && sh_type <= elfcpp::SHT_HIPROC)) + return parameters->target().should_include_section(sh_type); + + switch (sh_type) { case elfcpp::SHT_NULL: case elfcpp::SHT_SYMTAB: @@ -321,8 +689,7 @@ Layout::include_section(Sized_relobj*, const char* name, case elfcpp::SHT_GROUP: // If we are emitting relocations these should be handled // elsewhere. - gold_assert(!parameters->options().relocatable() - && !parameters->options().emit_relocs()); + gold_assert(!parameters->options().relocatable()); return false; case elfcpp::SHT_PROGBITS: @@ -336,26 +703,44 @@ Layout::include_section(Sized_relobj*, const char* name, && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) { // Debugging sections can only be recognized by name. - if (is_prefix_of(".debug", name) - && !is_lines_only_debug_section(name)) + if (is_prefix_of(".debug_", name) + && !is_lines_only_debug_section(name + 7)) + return false; + if (is_prefix_of(".zdebug_", name) + && !is_lines_only_debug_section(name + 8)) return false; } if (parameters->options().strip_debug_gdb() && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) { // Debugging sections can only be recognized by name. - if (is_prefix_of(".debug", name) - && !is_gdb_debug_section(name)) + if (is_prefix_of(".debug_", name) + && !is_gdb_debug_section(name + 7)) + return false; + if (is_prefix_of(".zdebug_", name) + && !is_gdb_debug_section(name + 8)) + return false; + } + if (parameters->options().gdb_index() + && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) + { + // When building .gdb_index, we can strip .debug_pubnames, + // .debug_pubtypes, and .debug_aranges sections. + if (is_prefix_of(".debug_", name) + && is_gdb_fast_lookup_section(name + 7)) + return false; + if (is_prefix_of(".zdebug_", name) + && is_gdb_fast_lookup_section(name + 8)) return false; } if (parameters->options().strip_lto_sections() - && !parameters->options().relocatable() - && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) - { - // Ignore LTO sections containing intermediate code. - if (is_prefix_of(".gnu.lto_", name)) - return false; - } + && !parameters->options().relocatable() + && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) + { + // Ignore LTO sections containing intermediate code. + if (is_prefix_of(".gnu.lto_", name)) + return false; + } // The GNU linker strips .gnu_debuglink sections, so we do too. // This is a feature used to keep debugging information in // separate files. @@ -398,19 +783,52 @@ Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set, return NULL; } +// When we put a .ctors or .dtors section with more than one word into +// a .init_array or .fini_array section, we need to reverse the words +// in the .ctors/.dtors section. This is because .init_array executes +// constructors front to back, where .ctors executes them back to +// front, and vice-versa for .fini_array/.dtors. Although we do want +// to remap .ctors/.dtors into .init_array/.fini_array because it can +// be more efficient, we don't want to change the order in which +// constructors/destructors are run. This set just keeps track of +// these sections which need to be reversed. It is only changed by +// Layout::layout. It should be a private member of Layout, but that +// would require layout.h to #include object.h to get the definition +// of Section_id. +static Unordered_set ctors_sections_in_init_array; + +// Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a +// .init_array/.fini_array section. + +bool +Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const +{ + return (ctors_sections_in_init_array.find(Section_id(relobj, shndx)) + != ctors_sections_in_init_array.end()); +} + // Return the output section to use for section NAME with type TYPE // and section flags FLAGS. NAME must be canonicalized in the string -// pool, and NAME_KEY is the key. IS_INTERP is true if this is the -// .interp section. IS_DYNAMIC_LINKER_SECTION is true if this section -// is used by the dynamic linker. IS_RELRO is true for a relro -// section. IS_LAST_RELRO is true for the last relro section. -// IS_FIRST_NON_RELRO is true for the first non-relro section. +// pool, and NAME_KEY is the key. ORDER is where this should appear +// in the output sections. IS_RELRO is true for a relro section. Output_section* Layout::get_output_section(const char* name, Stringpool::Key name_key, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, Output_section_order order, bool is_relro) { + elfcpp::Elf_Word lookup_type = type; + + // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and + // PREINIT_ARRAY like PROGBITS. This ensures that we combine + // .init_array, .fini_array, and .preinit_array sections by name + // whatever their type in the input file. We do this because the + // types are not always right in the input files. + if (lookup_type == elfcpp::SHT_INIT_ARRAY + || lookup_type == elfcpp::SHT_FINI_ARRAY + || lookup_type == elfcpp::SHT_PREINIT_ARRAY) + lookup_type = elfcpp::SHT_PROGBITS; + elfcpp::Elf_Xword lookup_flags = flags; // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine @@ -419,7 +837,7 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key, // controlling this. lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); - const Key key(name_key, std::make_pair(type, lookup_flags)); + const Key key(name_key, std::make_pair(lookup_type, lookup_flags)); const std::pair v(key, NULL); std::pair ins( this->section_name_map_.insert(v)); @@ -436,25 +854,29 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key, // there should be an option to control this. Output_section* os = NULL; - if (type == elfcpp::SHT_PROGBITS) + if (lookup_type == elfcpp::SHT_PROGBITS) { - if (flags == 0) - { - Output_section* same_name = this->find_output_section(name); - if (same_name != NULL - && same_name->type() == elfcpp::SHT_PROGBITS - && (same_name->flags() & elfcpp::SHF_TLS) == 0) - os = same_name; - } - else if ((flags & elfcpp::SHF_TLS) == 0) - { - elfcpp::Elf_Xword zero_flags = 0; - const Key zero_key(name_key, std::make_pair(type, zero_flags)); - Section_name_map::iterator p = - this->section_name_map_.find(zero_key); - if (p != this->section_name_map_.end()) + if (flags == 0) + { + Output_section* same_name = this->find_output_section(name); + if (same_name != NULL + && (same_name->type() == elfcpp::SHT_PROGBITS + || same_name->type() == elfcpp::SHT_INIT_ARRAY + || same_name->type() == elfcpp::SHT_FINI_ARRAY + || same_name->type() == elfcpp::SHT_PREINIT_ARRAY) + && (same_name->flags() & elfcpp::SHF_TLS) == 0) + os = same_name; + } + else if ((flags & elfcpp::SHF_TLS) == 0) + { + elfcpp::Elf_Xword zero_flags = 0; + const Key zero_key(name_key, std::make_pair(lookup_type, + zero_flags)); + Section_name_map::iterator p = + this->section_name_map_.find(zero_key); + if (p != this->section_name_map_.end()) os = p->second; - } + } } if (os == NULL) @@ -465,16 +887,55 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key, } } +// Returns TRUE iff NAME (an input section from RELOBJ) will +// be mapped to an output section that should be KEPT. + +bool +Layout::keep_input_section(const Relobj* relobj, const char* name) +{ + if (! this->script_options_->saw_sections_clause()) + return false; + + Script_sections* ss = this->script_options_->script_sections(); + const char* file_name = relobj == NULL ? NULL : relobj->name().c_str(); + Output_section** output_section_slot; + Script_sections::Section_type script_section_type; + bool keep; + + name = ss->output_section_name(file_name, name, &output_section_slot, + &script_section_type, &keep); + return name != NULL && keep; +} + +// Clear the input section flags that should not be copied to the +// output section. + +elfcpp::Elf_Xword +Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags) +{ + // Some flags in the input section should not be automatically + // copied to the output section. + input_section_flags &= ~ (elfcpp::SHF_INFO_LINK + | elfcpp::SHF_GROUP + | elfcpp::SHF_COMPRESSED + | elfcpp::SHF_MERGE + | elfcpp::SHF_STRINGS); + + // We only clear the SHF_LINK_ORDER flag in for + // a non-relocatable link. + if (!parameters->options().relocatable()) + input_section_flags &= ~elfcpp::SHF_LINK_ORDER; + + return input_section_flags; +} + // Pick the output section to use for section NAME, in input file // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a // linker created section. IS_INPUT_SECTION is true if we are // choosing an output section for an input section found in a input -// file. IS_INTERP is true if this is the .interp section. -// IS_DYNAMIC_LINKER_SECTION is true if this section is used by the -// dynamic linker. IS_RELRO is true for a relro section. -// IS_LAST_RELRO is true for the last relro section. -// IS_FIRST_NON_RELRO is true for the first non-relro section. This -// will return NULL if the input section should be discarded. +// file. ORDER is where this section should appear in the output +// sections. IS_RELRO is true for a relro section. This will return +// NULL if the input section should be discarded. Output_section* Layout::choose_output_section(const Relobj* relobj, const char* name, @@ -486,17 +947,7 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, // sections to segments. gold_assert(!is_input_section || !this->sections_are_attached_); - // Some flags in the input section should not be automatically - // copied to the output section. - flags &= ~ (elfcpp::SHF_INFO_LINK - | elfcpp::SHF_GROUP - | elfcpp::SHF_MERGE - | elfcpp::SHF_STRINGS); - - // We only clear the SHF_LINK_ORDER flag in for - // a non-relocatable link. - if (!parameters->options().relocatable()) - flags &= ~elfcpp::SHF_LINK_ORDER; + flags = this->get_output_section_flags(flags); if (this->script_options_->saw_sections_clause()) { @@ -508,8 +959,10 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, Output_section** output_section_slot; Script_sections::Section_type script_section_type; const char* orig_name = name; + bool keep; name = ss->output_section_name(file_name, name, &output_section_slot, - &script_section_type); + &script_section_type, &keep); + if (name == NULL) { gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' " @@ -581,14 +1034,30 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, // FIXME: Handle SHF_OS_NONCONFORMING somewhere. + size_t len = strlen(name); + std::string uncompressed_name; + + // Compressed debug sections should be mapped to the corresponding + // uncompressed section. + if (is_compressed_debug_section(name)) + { + uncompressed_name = + corresponding_uncompressed_section_name(std::string(name, len)); + name = uncompressed_name.c_str(); + len = uncompressed_name.length(); + } + // Turn NAME from the name of the input section into the name of the // output section. - - size_t len = strlen(name); if (is_input_section && !this->script_options_->saw_sections_clause() && !parameters->options().relocatable()) - name = Layout::output_section_name(name, &len); + { + const char *orig_name = name; + name = parameters->target().output_section_name(relobj, name, &len); + if (name == NULL) + name = Layout::output_section_name(relobj, orig_name, &len); + } Stringpool::Key name_key; name = this->namepool_.add_with_length(name, len, true, &name_key); @@ -598,6 +1067,74 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, return this->get_output_section(name, name_key, type, flags, order, is_relro); } +// For incremental links, record the initial fixed layout of a section +// from the base file, and return a pointer to the Output_section. + +template +Output_section* +Layout::init_fixed_output_section(const char* name, + elfcpp::Shdr& shdr) +{ + unsigned int sh_type = shdr.get_sh_type(); + + // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY, + // PRE_INIT_ARRAY, and NOTE sections. + // All others will be created from scratch and reallocated. + if (!can_incremental_update(sh_type)) + return NULL; + + // If we're generating a .gdb_index section, we need to regenerate + // it from scratch. + if (parameters->options().gdb_index() + && sh_type == elfcpp::SHT_PROGBITS + && strcmp(name, ".gdb_index") == 0) + return NULL; + + typename elfcpp::Elf_types::Elf_Addr sh_addr = shdr.get_sh_addr(); + typename elfcpp::Elf_types::Elf_Off sh_offset = shdr.get_sh_offset(); + typename elfcpp::Elf_types::Elf_WXword sh_size = shdr.get_sh_size(); + typename elfcpp::Elf_types::Elf_WXword sh_flags = shdr.get_sh_flags(); + typename elfcpp::Elf_types::Elf_WXword sh_addralign = + shdr.get_sh_addralign(); + + // Make the output section. + Stringpool::Key name_key; + name = this->namepool_.add(name, true, &name_key); + Output_section* os = this->get_output_section(name, name_key, sh_type, + sh_flags, ORDER_INVALID, false); + os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign); + if (sh_type != elfcpp::SHT_NOBITS) + this->free_list_.remove(sh_offset, sh_offset + sh_size); + return os; +} + +// Return the index by which an input section should be ordered. This +// is used to sort some .text sections, for compatibility with GNU ld. + +int +Layout::special_ordering_of_input_section(const char* name) +{ + // The GNU linker has some special handling for some sections that + // wind up in the .text section. Sections that start with these + // prefixes must appear first, and must appear in the order listed + // here. + static const char* const text_section_sort[] = + { + ".text.unlikely", + ".text.exit", + ".text.startup", + ".text.hot" + }; + + for (size_t i = 0; + i < sizeof(text_section_sort) / sizeof(text_section_sort[0]); + i++) + if (is_prefix_of(text_section_sort[i], name)) + return i; + + return -1; +} + // Return the output section to use for input section SHNDX, with name // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the // index of a relocation section which applies to this section, or 0 @@ -610,7 +1147,7 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, template Output_section* -Layout::layout(Sized_relobj* object, unsigned int shndx, +Layout::layout(Sized_relobj_file* object, unsigned int shndx, const char* name, const elfcpp::Shdr& shdr, unsigned int reloc_shndx, unsigned int, off_t* off) { @@ -619,73 +1156,137 @@ Layout::layout(Sized_relobj* object, unsigned int shndx, if (!this->include_section(object, name, shdr)) return NULL; - Output_section* os; - - // Sometimes .init_array*, .preinit_array* and .fini_array* do not have - // correct section types. Force them here. elfcpp::Elf_Word sh_type = shdr.get_sh_type(); - if (sh_type == elfcpp::SHT_PROGBITS) - { - static const char init_array_prefix[] = ".init_array"; - static const char preinit_array_prefix[] = ".preinit_array"; - static const char fini_array_prefix[] = ".fini_array"; - static size_t init_array_prefix_size = sizeof(init_array_prefix) - 1; - static size_t preinit_array_prefix_size = - sizeof(preinit_array_prefix) - 1; - static size_t fini_array_prefix_size = sizeof(fini_array_prefix) - 1; - - if (strncmp(name, init_array_prefix, init_array_prefix_size) == 0) - sh_type = elfcpp::SHT_INIT_ARRAY; - else if (strncmp(name, preinit_array_prefix, preinit_array_prefix_size) - == 0) - sh_type = elfcpp::SHT_PREINIT_ARRAY; - else if (strncmp(name, fini_array_prefix, fini_array_prefix_size) == 0) - sh_type = elfcpp::SHT_FINI_ARRAY; - } // In a relocatable link a grouped section must not be combined with // any other sections. + Output_section* os; if (parameters->options().relocatable() && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0) { + // Some flags in the input section should not be automatically + // copied to the output section. + elfcpp::Elf_Xword flags = (shdr.get_sh_flags() + & ~ elfcpp::SHF_COMPRESSED); name = this->namepool_.add(name, true, NULL); - os = this->make_output_section(name, sh_type, shdr.get_sh_flags(), + os = this->make_output_section(name, sh_type, flags, ORDER_INVALID, false); } else { - os = this->choose_output_section(object, name, sh_type, - shdr.get_sh_flags(), true, - ORDER_INVALID, false); + // Plugins can choose to place one or more subsets of sections in + // unique segments and this is done by mapping these section subsets + // to unique output sections. Check if this section needs to be + // remapped to a unique output section. + Section_segment_map::iterator it + = this->section_segment_map_.find(Const_section_id(object, shndx)); + if (it == this->section_segment_map_.end()) + { + os = this->choose_output_section(object, name, sh_type, + shdr.get_sh_flags(), true, + ORDER_INVALID, false); + } + else + { + // We know the name of the output section, directly call + // get_output_section here by-passing choose_output_section. + elfcpp::Elf_Xword flags + = this->get_output_section_flags(shdr.get_sh_flags()); + + const char* os_name = it->second->name; + Stringpool::Key name_key; + os_name = this->namepool_.add(os_name, true, &name_key); + os = this->get_output_section(os_name, name_key, sh_type, flags, + ORDER_INVALID, false); + if (!os->is_unique_segment()) + { + os->set_is_unique_segment(); + os->set_extra_segment_flags(it->second->flags); + os->set_segment_alignment(it->second->align); + } + } if (os == NULL) return NULL; } // By default the GNU linker sorts input sections whose names match - // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections - // are sorted by name. This is used to implement constructor - // priority ordering. We are compatible. + // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The + // sections are sorted by name. This is used to implement + // constructor priority ordering. We are compatible. When we put + // .ctor sections in .init_array and .dtor sections in .fini_array, + // we must also sort plain .ctor and .dtor sections. if (!this->script_options_->saw_sections_clause() + && !parameters->options().relocatable() && (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name) || is_prefix_of(".init_array.", name) - || is_prefix_of(".fini_array.", name))) + || is_prefix_of(".fini_array.", name) + || (parameters->options().ctors_in_init_array() + && (strcmp(name, ".ctors") == 0 + || strcmp(name, ".dtors") == 0)))) + os->set_must_sort_attached_input_sections(); + + // By default the GNU linker sorts some special text sections ahead + // of others. We are compatible. + if (parameters->options().text_reorder() + && !this->script_options_->saw_sections_clause() + && !this->is_section_ordering_specified() + && !parameters->options().relocatable() + && Layout::special_ordering_of_input_section(name) >= 0) os->set_must_sort_attached_input_sections(); + // If this is a .ctors or .ctors.* section being mapped to a + // .init_array section, or a .dtors or .dtors.* section being mapped + // to a .fini_array section, we will need to reverse the words if + // there is more than one. Record this section for later. See + // ctors_sections_in_init_array above. + if (!this->script_options_->saw_sections_clause() + && !parameters->options().relocatable() + && shdr.get_sh_size() > size / 8 + && (((strcmp(name, ".ctors") == 0 + || is_prefix_of(".ctors.", name)) + && strcmp(os->name(), ".init_array") == 0) + || ((strcmp(name, ".dtors") == 0 + || is_prefix_of(".dtors.", name)) + && strcmp(os->name(), ".fini_array") == 0))) + ctors_sections_in_init_array.insert(Section_id(object, shndx)); + // FIXME: Handle SHF_LINK_ORDER somewhere. + elfcpp::Elf_Xword orig_flags = os->flags(); + *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx, this->script_options_->saw_sections_clause()); + + // If the flags changed, we may have to change the order. + if ((orig_flags & elfcpp::SHF_ALLOC) != 0) + { + orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); + elfcpp::Elf_Xword new_flags = + os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); + if (orig_flags != new_flags) + os->set_order(this->default_section_order(os, false)); + } + this->have_added_input_section_ = true; return os; } +// Maps section SECN to SEGMENT s. +void +Layout::insert_section_segment_map(Const_section_id secn, + Unique_segment_info *s) +{ + gold_assert(this->unique_segment_for_sections_specified_); + this->section_segment_map_[secn] = s; +} + // Handle a relocation section when doing a relocatable link. template Output_section* -Layout::layout_reloc(Sized_relobj* object, +Layout::layout_reloc(Sized_relobj_file* object, unsigned int, const elfcpp::Shdr& shdr, Output_section* data_section, @@ -752,7 +1353,7 @@ Layout::layout_reloc(Sized_relobj* object, template void Layout::layout_group(Symbol_table* symtab, - Sized_relobj* object, + Sized_relobj_file* object, unsigned int, const char* group_section_name, const char* signature, @@ -802,7 +1403,7 @@ Layout::layout_group(Symbol_table* symtab, template Output_section* -Layout::layout_eh_frame(Sized_relobj* object, +Layout::layout_eh_frame(Sized_relobj_file* object, const unsigned char* symbols, off_t symbols_size, const unsigned char* symbol_names, @@ -812,11 +1413,97 @@ Layout::layout_eh_frame(Sized_relobj* object, unsigned int reloc_shndx, unsigned int reloc_type, off_t* off) { - gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS); + gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS + || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND); gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0); - const char* const name = ".eh_frame"; - Output_section* os = this->choose_output_section(object, name, + Output_section* os = this->make_eh_frame_section(object); + if (os == NULL) + return NULL; + + gold_assert(this->eh_frame_section_ == os); + + elfcpp::Elf_Xword orig_flags = os->flags(); + + Eh_frame::Eh_frame_section_disposition disp = + Eh_frame::EH_UNRECOGNIZED_SECTION; + if (!parameters->incremental()) + { + disp = this->eh_frame_data_->add_ehframe_input_section(object, + symbols, + symbols_size, + symbol_names, + symbol_names_size, + shndx, + reloc_shndx, + reloc_type); + } + + if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION) + { + os->update_flags_for_input_section(shdr.get_sh_flags()); + + // A writable .eh_frame section is a RELRO section. + if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)) + != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))) + { + os->set_is_relro(); + os->set_order(ORDER_RELRO); + } + + *off = -1; + return os; + } + + if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_) + { + // We found the end marker section, so now we can add the set of + // optimized sections to the output section. We need to postpone + // adding this until we've found a section we can optimize so that + // the .eh_frame section in crtbeginT.o winds up at the start of + // the output section. + os->add_output_section_data(this->eh_frame_data_); + this->added_eh_frame_data_ = true; + } + + // We couldn't handle this .eh_frame section for some reason. + // Add it as a normal section. + bool saw_sections_clause = this->script_options_->saw_sections_clause(); + *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr, + reloc_shndx, saw_sections_clause); + this->have_added_input_section_ = true; + + if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)) + != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))) + os->set_order(this->default_section_order(os, false)); + + return os; +} + +void +Layout::finalize_eh_frame_section() +{ + // If we never found an end marker section, we need to add the + // optimized eh sections to the output section now. + if (!parameters->incremental() + && this->eh_frame_section_ != NULL + && !this->added_eh_frame_data_) + { + this->eh_frame_section_->add_output_section_data(this->eh_frame_data_); + this->added_eh_frame_data_ = true; + } +} + +// Create and return the magic .eh_frame section. Create +// .eh_frame_hdr also if appropriate. OBJECT is the object with the +// input .eh_frame section; it may be NULL. + +Output_section* +Layout::make_eh_frame_section(const Relobj* object) +{ + // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than + // SHT_PROGBITS. + Output_section* os = this->choose_output_section(object, ".eh_frame", elfcpp::SHT_PROGBITS, elfcpp::SHF_ALLOC, false, ORDER_EHFRAME, false); @@ -828,7 +1515,9 @@ Layout::layout_eh_frame(Sized_relobj* object, this->eh_frame_section_ = os; this->eh_frame_data_ = new Eh_frame(); - if (parameters->options().eh_frame_hdr()) + // For incremental linking, we do not optimize .eh_frame sections + // or create a .eh_frame_hdr section. + if (parameters->options().eh_frame_hdr() && !parameters->incremental()) { Output_section* hdr_os = this->choose_output_section(NULL, ".eh_frame_hdr", @@ -858,42 +1547,63 @@ Layout::layout_eh_frame(Sized_relobj* object, } } - gold_assert(this->eh_frame_section_ == os); + return os; +} - if (this->eh_frame_data_->add_ehframe_input_section(object, - symbols, - symbols_size, - symbol_names, - symbol_names_size, - shndx, - reloc_shndx, - reloc_type)) - { - os->update_flags_for_input_section(shdr.get_sh_flags()); +// Add an exception frame for a PLT. This is called from target code. - // We found a .eh_frame section we are going to optimize, so now - // we can add the set of optimized sections to the output - // section. We need to postpone adding this until we've found a - // section we can optimize so that the .eh_frame section in - // crtbegin.o winds up at the start of the output section. - if (!this->added_eh_frame_data_) - { - os->add_output_section_data(this->eh_frame_data_); - this->added_eh_frame_data_ = true; - } - *off = -1; +void +Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data, + size_t cie_length, const unsigned char* fde_data, + size_t fde_length) +{ + if (parameters->incremental()) + { + // FIXME: Maybe this could work some day.... + return; } - else + Output_section* os = this->make_eh_frame_section(NULL); + if (os == NULL) + return; + this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length, + fde_data, fde_length); + if (!this->added_eh_frame_data_) { - // We couldn't handle this .eh_frame section for some reason. - // Add it as a normal section. - bool saw_sections_clause = this->script_options_->saw_sections_clause(); - *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx, - saw_sections_clause); - this->have_added_input_section_ = true; + os->add_output_section_data(this->eh_frame_data_); + this->added_eh_frame_data_ = true; } +} - return os; +// Scan a .debug_info or .debug_types section, and add summary +// information to the .gdb_index section. + +template +void +Layout::add_to_gdb_index(bool is_type_unit, + Sized_relobj* object, + const unsigned char* symbols, + off_t symbols_size, + unsigned int shndx, + unsigned int reloc_shndx, + unsigned int reloc_type) +{ + if (this->gdb_index_data_ == NULL) + { + Output_section* os = this->choose_output_section(NULL, ".gdb_index", + elfcpp::SHT_PROGBITS, 0, + false, ORDER_INVALID, + false); + if (os == NULL) + return; + + this->gdb_index_data_ = new Gdb_index(os); + os->add_output_section_data(this->gdb_index_data_); + os->set_after_input_sections(); + } + + this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols, + symbols_size, shndx, reloc_shndx, + reloc_type); } // Add POSD to an output section using NAME, TYPE, and FLAGS. Return @@ -925,30 +1635,6 @@ Layout::section_flags_to_segment(elfcpp::Elf_Xword flags) return ret; } -// Sometimes we compress sections. This is typically done for -// sections that are not part of normal program execution (such as -// .debug_* sections), and where the readers of these sections know -// how to deal with compressed sections. This routine doesn't say for -// certain whether we'll compress -- it depends on commandline options -// as well -- just whether this section is a candidate for compression. -// (The Output_compressed_section class decides whether to compress -// a given section, and picks the name of the compressed section.) - -static bool -is_compressible_debug_section(const char* secname) -{ - return (is_prefix_of(".debug", secname)); -} - -// We may see compressed debug sections in input files. Return TRUE -// if this is the name of a compressed debug section. - -bool -is_compressed_debug_section(const char* secname) -{ - return (is_prefix_of(".zdebug", secname)); -} - // Make a new Output_section, and attach it to segments as // appropriate. ORDER is the order in which this section should // appear in the output segment. IS_RELRO is true if this is a relro @@ -966,25 +1652,37 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, os = new Output_compressed_section(¶meters->options(), name, type, flags); else if ((flags & elfcpp::SHF_ALLOC) == 0 - && parameters->options().strip_debug_non_line() - && strcmp(".debug_abbrev", name) == 0) + && parameters->options().strip_debug_non_line() + && strcmp(".debug_abbrev", name) == 0) { os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section( - name, type, flags); + name, type, flags); if (this->debug_info_) - this->debug_info_->set_abbreviations(this->debug_abbrev_); + this->debug_info_->set_abbreviations(this->debug_abbrev_); } else if ((flags & elfcpp::SHF_ALLOC) == 0 - && parameters->options().strip_debug_non_line() - && strcmp(".debug_info", name) == 0) + && parameters->options().strip_debug_non_line() + && strcmp(".debug_info", name) == 0) { os = this->debug_info_ = new Output_reduced_debug_info_section( - name, type, flags); + name, type, flags); if (this->debug_abbrev_) - this->debug_info_->set_abbreviations(this->debug_abbrev_); + this->debug_info_->set_abbreviations(this->debug_abbrev_); } else { + // Sometimes .init_array*, .preinit_array* and .fini_array* do + // not have correct section types. Force them here. + if (type == elfcpp::SHT_PROGBITS) + { + if (is_prefix_of(".init_array", name)) + type = elfcpp::SHT_INIT_ARRAY; + else if (is_prefix_of(".preinit_array", name)) + type = elfcpp::SHT_PREINIT_ARRAY; + else if (is_prefix_of(".fini_array", name)) + type = elfcpp::SHT_FINI_ARRAY; + } + // FIXME: const_cast is ugly. Target* target = const_cast(¶meters->target()); os = target->make_output_section(name, type, flags); @@ -995,25 +1693,29 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, bool is_relro_local = false; if (!this->script_options_->saw_sections_clause() && parameters->options().relro() - && type == elfcpp::SHT_PROGBITS && (flags & elfcpp::SHF_ALLOC) != 0 && (flags & elfcpp::SHF_WRITE) != 0) { - if (strcmp(name, ".data.rel.ro") == 0) - is_relro = true; - else if (strcmp(name, ".data.rel.ro.local") == 0) + if (type == elfcpp::SHT_PROGBITS) { - is_relro = true; - is_relro_local = true; + if ((flags & elfcpp::SHF_TLS) != 0) + is_relro = true; + else if (strcmp(name, ".data.rel.ro") == 0) + is_relro = true; + else if (strcmp(name, ".data.rel.ro.local") == 0) + { + is_relro = true; + is_relro_local = true; + } + else if (strcmp(name, ".ctors") == 0 + || strcmp(name, ".dtors") == 0 + || strcmp(name, ".jcr") == 0) + is_relro = true; } else if (type == elfcpp::SHT_INIT_ARRAY || type == elfcpp::SHT_FINI_ARRAY || type == elfcpp::SHT_PREINIT_ARRAY) is_relro = true; - else if (strcmp(name, ".ctors") == 0 - || strcmp(name, ".dtors") == 0 - || strcmp(name, ".jcr") == 0) - is_relro = true; } if (is_relro) @@ -1032,12 +1734,29 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, // do the same. We need to know that this might happen before we // attach any input sections. if (!this->script_options_->saw_sections_clause() - && (strcmp(name, ".ctors") == 0 - || strcmp(name, ".dtors") == 0 - || strcmp(name, ".init_array") == 0 - || strcmp(name, ".fini_array") == 0)) + && !parameters->options().relocatable() + && (strcmp(name, ".init_array") == 0 + || strcmp(name, ".fini_array") == 0 + || (!parameters->options().ctors_in_init_array() + && (strcmp(name, ".ctors") == 0 + || strcmp(name, ".dtors") == 0)))) + os->set_may_sort_attached_input_sections(); + + // The GNU linker by default sorts .text.{unlikely,exit,startup,hot} + // sections before other .text sections. We are compatible. We + // need to know that this might happen before we attach any input + // sections. + if (parameters->options().text_reorder() + && !this->script_options_->saw_sections_clause() + && !this->is_section_ordering_specified() + && !parameters->options().relocatable() + && strcmp(name, ".text") == 0) os->set_may_sort_attached_input_sections(); + // GNU linker sorts section by name with --sort-section=name. + if (strcmp(parameters->options().sort_section(), "name") == 0) + os->set_must_sort_attached_input_sections(); + // Check for .stab*str sections, as .stab* sections need to link to // them. if (type == elfcpp::SHT_STRTAB @@ -1046,11 +1765,40 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, && strcmp(name + strlen(name) - 3, "str") == 0) this->have_stabstr_section_ = true; + // During a full incremental link, we add patch space to most + // PROGBITS and NOBITS sections. Flag those that may be + // arbitrarily padded. + if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS) + && order != ORDER_INTERP + && order != ORDER_INIT + && order != ORDER_PLT + && order != ORDER_FINI + && order != ORDER_RELRO_LAST + && order != ORDER_NON_RELRO_FIRST + && strcmp(name, ".eh_frame") != 0 + && strcmp(name, ".ctors") != 0 + && strcmp(name, ".dtors") != 0 + && strcmp(name, ".jcr") != 0) + { + os->set_is_patch_space_allowed(); + + // Certain sections require "holes" to be filled with + // specific fill patterns. These fill patterns may have + // a minimum size, so we must prevent allocations from the + // free list that leave a hole smaller than the minimum. + if (strcmp(name, ".debug_info") == 0) + os->set_free_space_fill(new Output_fill_debug_info(false)); + else if (strcmp(name, ".debug_types") == 0) + os->set_free_space_fill(new Output_fill_debug_info(true)); + else if (strcmp(name, ".debug_line") == 0) + os->set_free_space_fill(new Output_fill_debug_line()); + } + // If we have already attached the sections to segments, then we // need to attach this one now. This happens for sections created // directly by the linker. if (this->sections_are_attached_) - this->attach_section_to_segment(os); + this->attach_section_to_segment(¶meters->target(), os); return os; } @@ -1127,12 +1875,12 @@ Layout::default_section_order(Output_section* os, bool is_relro_local) // seen all the input sections. void -Layout::attach_sections_to_segments() +Layout::attach_sections_to_segments(const Target* target) { for (Section_list::iterator p = this->section_list_.begin(); p != this->section_list_.end(); ++p) - this->attach_section_to_segment(*p); + this->attach_section_to_segment(target, *p); this->sections_are_attached_ = true; } @@ -1140,18 +1888,19 @@ Layout::attach_sections_to_segments() // Attach an output section to a segment. void -Layout::attach_section_to_segment(Output_section* os) +Layout::attach_section_to_segment(const Target* target, Output_section* os) { if ((os->flags() & elfcpp::SHF_ALLOC) == 0) this->unattached_section_list_.push_back(os); else - this->attach_allocated_section_to_segment(os); + this->attach_allocated_section_to_segment(target, os); } // Attach an allocated output section to a segment. void -Layout::attach_allocated_section_to_segment(Output_section* os) +Layout::attach_allocated_section_to_segment(const Target* target, + Output_section* os) { elfcpp::Elf_Xword flags = os->flags(); gold_assert((flags & elfcpp::SHF_ALLOC) != 0); @@ -1170,6 +1919,10 @@ Layout::attach_allocated_section_to_segment(Output_section* os) elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags); + // If this output section's segment has extra flags that need to be set, + // coming from a linker plugin, do that. + seg_flags |= os->extra_segment_flags(); + // Check for --section-start. uint64_t addr; bool is_address_set = parameters->options().section_start(os->name(), &addr); @@ -1182,53 +1935,67 @@ Layout::attach_allocated_section_to_segment(Output_section* os) // have to use a linker script. Segment_list::const_iterator p; - for (p = this->segment_list_.begin(); - p != this->segment_list_.end(); - ++p) + if (!os->is_unique_segment()) { - if ((*p)->type() != elfcpp::PT_LOAD) - continue; - if (!parameters->options().omagic() - && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W)) - continue; - if (parameters->options().rosegment() - && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X)) - continue; - // If -Tbss was specified, we need to separate the data and BSS - // segments. - if (parameters->options().user_set_Tbss()) + for (p = this->segment_list_.begin(); + p != this->segment_list_.end(); + ++p) { - if ((os->type() == elfcpp::SHT_NOBITS) - == (*p)->has_any_data_sections()) + if ((*p)->type() != elfcpp::PT_LOAD) continue; - } - if (os->is_large_data_section() && !(*p)->is_large_data_segment()) - continue; - - if (is_address_set) - { - if ((*p)->are_addresses_set()) + if ((*p)->is_unique_segment()) continue; + if (!parameters->options().omagic() + && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W)) + continue; + if ((target->isolate_execinstr() || parameters->options().rosegment()) + && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X)) + continue; + // If -Tbss was specified, we need to separate the data and BSS + // segments. + if (parameters->options().user_set_Tbss()) + { + if ((os->type() == elfcpp::SHT_NOBITS) + == (*p)->has_any_data_sections()) + continue; + } + if (os->is_large_data_section() && !(*p)->is_large_data_segment()) + continue; + + if (is_address_set) + { + if ((*p)->are_addresses_set()) + continue; - (*p)->add_initial_output_data(os); - (*p)->update_flags_for_output_section(seg_flags); - (*p)->set_addresses(addr, addr); + (*p)->add_initial_output_data(os); + (*p)->update_flags_for_output_section(seg_flags); + (*p)->set_addresses(addr, addr); + break; + } + + (*p)->add_output_section_to_load(this, os, seg_flags); break; } - - (*p)->add_output_section_to_load(this, os, seg_flags); - break; } - if (p == this->segment_list_.end()) + if (p == this->segment_list_.end() + || os->is_unique_segment()) { Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD, - seg_flags); + seg_flags); if (os->is_large_data_section()) oseg->set_is_large_data_segment(); oseg->add_output_section_to_load(this, os, seg_flags); if (is_address_set) oseg->set_addresses(addr, addr); + // Check if segment should be marked unique. For segments marked + // unique by linker plugins, set the new alignment if specified. + if (os->is_unique_segment()) + { + oseg->set_is_unique_segment(); + if (os->segment_alignment() != 0) + oseg->set_minimum_p_align(os->segment_alignment()); + } } // If we see a loadable SHT_NOTE section, we create a PT_NOTE @@ -1237,24 +2004,24 @@ Layout::attach_allocated_section_to_segment(Output_section* os) { // See if we already have an equivalent PT_NOTE segment. for (p = this->segment_list_.begin(); - p != segment_list_.end(); - ++p) - { - if ((*p)->type() == elfcpp::PT_NOTE - && (((*p)->flags() & elfcpp::PF_W) - == (seg_flags & elfcpp::PF_W))) - { - (*p)->add_output_section_to_nonload(os, seg_flags); - break; - } - } + p != segment_list_.end(); + ++p) + { + if ((*p)->type() == elfcpp::PT_NOTE + && (((*p)->flags() & elfcpp::PF_W) + == (seg_flags & elfcpp::PF_W))) + { + (*p)->add_output_section_to_nonload(os, seg_flags); + break; + } + } if (p == this->segment_list_.end()) - { - Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE, - seg_flags); - oseg->add_output_section_to_nonload(os, seg_flags); - } + { + Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE, + seg_flags); + oseg->add_output_section_to_nonload(os, seg_flags); + } } // If we see a loadable SHF_TLS section, we create a PT_TLS @@ -1275,6 +2042,20 @@ Layout::attach_allocated_section_to_segment(Output_section* os) this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags); this->relro_segment_->add_output_section_to_nonload(os, seg_flags); } + + // If we see a section named .interp, put it into a PT_INTERP + // segment. This seems broken to me, but this is what GNU ld does, + // and glibc expects it. + if (strcmp(os->name(), ".interp") == 0 + && !this->script_options_->saw_phdrs_clause()) + { + if (this->interp_segment_ == NULL) + this->make_output_segment(elfcpp::PT_INTERP, seg_flags); + else + gold_warning(_("multiple '.interp' sections in input files " + "may cause confusing PT_INTERP segment")); + this->interp_segment_->add_output_section_to_nonload(os, seg_flags); + } } // Make an output section for a script. @@ -1327,15 +2108,28 @@ Layout::expected_segment_count() const // object. On some targets that will force an executable stack. void -Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags) +Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags, + const Object* obj) { if (!seen_gnu_stack) - this->input_without_gnu_stack_note_ = true; + { + this->input_without_gnu_stack_note_ = true; + if (parameters->options().warn_execstack() + && parameters->target().is_default_stack_executable()) + gold_warning(_("%s: missing .note.GNU-stack section" + " implies executable stack"), + obj->name().c_str()); + } else { this->input_with_gnu_stack_note_ = true; if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0) - this->input_requires_executable_stack_ = true; + { + this->input_requires_executable_stack_ = true; + if (parameters->options().warn_execstack()) + gold_warning(_("%s: requires executable stack"), + obj->name().c_str()); + } } } @@ -1345,7 +2139,7 @@ void Layout::create_notes() { this->create_gold_note(); - this->create_executable_stack_info(); + this->create_stack_segment(); this->create_build_id(); } @@ -1365,15 +2159,20 @@ Layout::create_initial_dynamic_sections(Symbol_table* symtab) false, ORDER_RELRO, true); - this->dynamic_symbol_ = - symtab->define_in_output_data("_DYNAMIC", NULL, Symbol_table::PREDEFINED, - this->dynamic_section_, 0, 0, - elfcpp::STT_OBJECT, elfcpp::STB_LOCAL, - elfcpp::STV_HIDDEN, 0, false, false); + // A linker script may discard .dynamic, so check for NULL. + if (this->dynamic_section_ != NULL) + { + this->dynamic_symbol_ = + symtab->define_in_output_data("_DYNAMIC", NULL, + Symbol_table::PREDEFINED, + this->dynamic_section_, 0, 0, + elfcpp::STT_OBJECT, elfcpp::STB_LOCAL, + elfcpp::STV_HIDDEN, 0, false, false); - this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_); + this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_); - this->dynamic_section_->add_output_section_data(this->dynamic_data_); + this->dynamic_section_->add_output_section_data(this->dynamic_data_); + } } // For each output section whose name can be represented as C symbol, @@ -1392,9 +2191,9 @@ Layout::define_section_symbols(Symbol_table* symtab) { const std::string name_string(name); const std::string start_name(cident_section_start_prefix - + name_string); + + name_string); const std::string stop_name(cident_section_stop_prefix - + name_string); + + name_string); symtab->define_in_output_data(start_name.c_str(), NULL, // version @@ -1460,7 +2259,7 @@ Layout::define_group_signatures(Symbol_table* symtab) // necessary. Output_segment* -Layout::find_first_load_seg() +Layout::find_first_load_seg(const Target* target) { Output_segment* best = NULL; for (Segment_list::const_iterator p = this->segment_list_.begin(); @@ -1470,11 +2269,13 @@ Layout::find_first_load_seg() if ((*p)->type() == elfcpp::PT_LOAD && ((*p)->flags() & elfcpp::PF_R) != 0 && (parameters->options().omagic() - || ((*p)->flags() & elfcpp::PF_W) == 0)) - { - if (best == NULL || this->segment_precedes(*p, best)) - best = *p; - } + || ((*p)->flags() & elfcpp::PF_W) == 0) + && (!target->isolate_execinstr() + || ((*p)->flags() & elfcpp::PF_X) == 0)) + { + if (best == NULL || this->segment_precedes(*p, best)) + best = *p; + } } if (best != NULL) return best; @@ -1532,10 +2333,10 @@ Layout::restore_segments(const Segment_states* segment_states) this->relro_segment_ = segment; ++list_iter; - } + } else { - list_iter = this->segment_list_.erase(list_iter); + list_iter = this->segment_list_.erase(list_iter); // This is a segment created during section layout. It should be // safe to remove it since we should have removed all pointers to it. delete segment; @@ -1568,7 +2369,7 @@ Layout::clean_up_after_relaxation() (*p)->reset_address_and_file_offset(); } - + // Reset special output object address and file offsets. for (Data_list::iterator p = this->special_output_list_.begin(); p != this->special_output_list_.end(); @@ -1582,7 +2383,21 @@ Layout::clean_up_after_relaxation() p != this->script_output_section_data_list_.end(); ++p) delete *p; - this->script_output_section_data_list_.clear(); + this->script_output_section_data_list_.clear(); + + // Special-case fill output objects are recreated each time through + // the relaxation loop. + this->reset_relax_output(); +} + +void +Layout::reset_relax_output() +{ + for (Data_list::const_iterator p = this->relax_output_list_.begin(); + p != this->relax_output_list_.end(); + ++p) + delete *p; + this->relax_output_list_.clear(); } // Prepare for relaxation. @@ -1605,16 +2420,33 @@ Layout::prepare_for_relaxation() if (is_debugging_enabled(DEBUG_RELAXATION)) this->relaxation_debug_check_->check_output_data_for_reset_values( - this->section_list_, this->special_output_list_); + this->section_list_, this->special_output_list_, + this->relax_output_list_); // Also enable recording of output section data from scripts. this->record_output_section_data_from_script_ = true; } +// If the user set the address of the text segment, that may not be +// compatible with putting the segment headers and file headers into +// that segment. For isolate_execinstr() targets, it's the rodata +// segment rather than text where we might put the headers. +static inline bool +load_seg_unusable_for_headers(const Target* target) +{ + const General_options& options = parameters->options(); + if (target->isolate_execinstr()) + return (options.user_set_Trodata_segment() + && options.Trodata_segment() % target->abi_pagesize() != 0); + else + return (options.user_set_Ttext() + && options.Ttext() % target->abi_pagesize() != 0); +} + // Relaxation loop body: If target has no relaxation, this runs only once // Otherwise, the target relaxation hook is called at the end of // each iteration. If the hook returns true, it means re-layout of -// section is required. +// section is required. // // The number of segments created by a linking script without a PHDRS // clause may be affected by section sizes and alignments. There is @@ -1624,8 +2456,8 @@ Layout::prepare_for_relaxation() // layout. In order to be able to restart the section layout, we keep // a copy of the segment list right before the relaxation loop and use // that to restore the segments. -// -// PASS is the current relaxation pass number. +// +// PASS is the current relaxation pass number. // SYMTAB is a symbol table. // PLOAD_SEG is the address of a pointer for the load segment. // PHDR_SEG is a pointer to the PHDR segment. @@ -1657,17 +2489,17 @@ Layout::relaxation_loop_body( else if (parameters->options().relocatable()) load_seg = NULL; else - load_seg = this->find_first_load_seg(); + load_seg = this->find_first_load_seg(target); if (parameters->options().oformat_enum() != General_options::OBJECT_FORMAT_ELF) load_seg = NULL; - // If the user set the address of the text segment, that may not be - // compatible with putting the segment headers and file headers into - // that segment. - if (parameters->options().user_set_Ttext()) - load_seg = NULL; + if (load_seg_unusable_for_headers(target)) + { + load_seg = NULL; + phdr_seg = NULL; + } gold_assert(phdr_seg == NULL || load_seg != NULL @@ -1710,9 +2542,9 @@ Layout::relaxation_loop_body( load_seg->add_initial_output_data(z); } if (load_seg != NULL) - load_seg->add_initial_output_data(segment_headers); + load_seg->add_initial_output_data(segment_headers); if (phdr_seg != NULL) - phdr_seg->add_initial_output_data(segment_headers); + phdr_seg->add_initial_output_data(segment_headers); } // Lay out the file header. @@ -1773,17 +2605,17 @@ Layout::find_section_order_index(const std::string& section_name) ++it) { if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0) - { - map_it = this->input_section_position_.find(*it); - gold_assert(map_it != this->input_section_position_.end()); - return map_it->second; - } + { + map_it = this->input_section_position_.find(*it); + gold_assert(map_it != this->input_section_position_.end()); + return map_it->second; + } } return 0; } // Read the sequence of input sections from the file specified with -// --section-ordering-file. +// option --section-ordering-file. void Layout::read_layout_from_file() @@ -1795,25 +2627,26 @@ Layout::read_layout_from_file() in.open(filename); if (!in) gold_fatal(_("unable to open --section-ordering-file file %s: %s"), - filename, strerror(errno)); + filename, strerror(errno)); std::getline(in, line); // this chops off the trailing \n, if any unsigned int position = 1; + this->set_section_ordering_specified(); while (in) { if (!line.empty() && line[line.length() - 1] == '\r') // Windows - line.resize(line.length() - 1); + line.resize(line.length() - 1); // Ignore comments, beginning with '#' if (line[0] == '#') - { - std::getline(in, line); - continue; - } + { + std::getline(in, line); + continue; + } this->input_section_position_[line] = position; // Store all glob patterns in a vector. if (is_wildcard_string(line.c_str())) - this->input_section_glob_.push_back(line); + this->input_section_glob_.push_back(line); position++; std::getline(in, line); } @@ -1877,15 +2710,18 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, std::vector dynamic_symbols; unsigned int local_dynamic_count; Versions versions(*this->script_options()->version_script_info(), - &this->dynpool_); + &this->dynpool_); this->create_dynamic_symtab(input_objects, symtab, &dynstr, &local_dynamic_count, &dynamic_symbols, &versions); // Create the .interp section to hold the name of the - // interpreter, and put it in a PT_INTERP segment. - if (!parameters->options().shared()) - this->create_interp(target); + // interpreter, and put it in a PT_INTERP segment. Don't do it + // if we saw a .interp section in an input file. + if ((!parameters->options().shared() + || parameters->options().dynamic_linker() != NULL) + && this->interp_segment_ == NULL) + this->create_interp(target); // Finish the .dynamic section to hold the dynamic data, and put // it in a PT_DYNAMIC segment. @@ -1904,7 +2740,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, // after we call create_version_sections. this->set_dynamic_symbol_size(symtab); } - + // Create segment headers. Output_segment_headers* segment_headers = (parameters->options().relocatable() @@ -1912,9 +2748,8 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, : new Output_segment_headers(this->segment_list_)); // Lay out the file header. - Output_file_header* file_header - = new Output_file_header(target, symtab, segment_headers, - parameters->options().entry()); + Output_file_header* file_header = new Output_file_header(target, symtab, + segment_headers); this->special_output_list_.push_back(file_header); if (segment_headers != NULL) @@ -1924,7 +2759,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, // a linker script. if (this->script_options_->saw_sections_clause()) this->place_orphan_sections_in_script(); - + Output_segment* load_seg; off_t off; unsigned int shndx; @@ -1933,7 +2768,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, // Take a snapshot of the section layout as needed. if (target->may_relax()) this->prepare_for_relaxation(); - + // Run the relaxation loop to lay out sections. do { @@ -1945,6 +2780,18 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, while (target->may_relax() && target->relax(pass, input_objects, symtab, this, task)); + // If there is a load segment that contains the file and program headers, + // provide a symbol __ehdr_start pointing there. + // A program can use this to examine itself robustly. + Symbol *ehdr_start = symtab->lookup("__ehdr_start"); + if (ehdr_start != NULL && ehdr_start->is_predefined()) + { + if (load_seg != NULL) + ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START); + else + ehdr_start->set_undefined(); + } + // Set the file offsets of all the non-data sections we've seen so // far which don't have to wait for the input sections. We need // this in order to finalize local symbols in non-allocated @@ -2112,7 +2959,8 @@ Layout::create_note(const char* name, int note_type, void Layout::create_gold_note() { - if (parameters->options().relocatable()) + if (parameters->options().relocatable() + || parameters->incremental_update()) return; std::string desc = std::string("gold ") + gold::get_version_string(); @@ -2141,18 +2989,29 @@ Layout::create_gold_note() // executable. Otherwise, if at least one input file a // .note.GNU-stack section, and some input file has no .note.GNU-stack // section, we use the target default for whether the stack should be -// executable. Otherwise, we don't generate a stack note. When -// generating a object file, we create a .note.GNU-stack section with -// the appropriate marking. When generating an executable or shared -// library, we create a PT_GNU_STACK segment. +// executable. If -z stack-size was used to set a p_memsz value for +// PT_GNU_STACK, we generate the segment regardless. Otherwise, we +// don't generate a stack note. When generating a object file, we +// create a .note.GNU-stack section with the appropriate marking. +// When generating an executable or shared library, we create a +// PT_GNU_STACK segment. void -Layout::create_executable_stack_info() +Layout::create_stack_segment() { bool is_stack_executable; if (parameters->options().is_execstack_set()) - is_stack_executable = parameters->options().is_stack_executable(); - else if (!this->input_with_gnu_stack_note_) + { + is_stack_executable = parameters->options().is_stack_executable(); + if (!is_stack_executable + && this->input_requires_executable_stack_ + && parameters->options().warn_execstack()) + gold_warning(_("one or more inputs require executable stack, " + "but -z noexecstack was given")); + } + else if (!this->input_with_gnu_stack_note_ + && (!parameters->options().user_set_stack_size() + || parameters->options().relocatable())) return; else { @@ -2181,7 +3040,12 @@ Layout::create_executable_stack_info() int flags = elfcpp::PF_R | elfcpp::PF_W; if (is_stack_executable) flags |= elfcpp::PF_X; - this->make_output_segment(elfcpp::PT_GNU_STACK, flags); + Output_segment* seg = + this->make_output_segment(elfcpp::PT_GNU_STACK, flags); + seg->set_size(parameters->options().stack_size()); + // BFD lets targets override this default alignment, but the only + // targets that do so are ones that Gold does not support so far. + seg->set_minimum_p_align(16); } } @@ -2203,10 +3067,11 @@ Layout::create_build_id() std::string desc; if (strcmp(style, "md5") == 0) descsz = 128 / 8; - else if (strcmp(style, "sha1") == 0) + else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0)) descsz = 160 / 8; else if (strcmp(style, "uuid") == 0) { +#ifndef __MINGW32__ const size_t uuidsz = 128 / 8; char buffer[uuidsz]; @@ -2229,6 +3094,26 @@ Layout::create_build_id() desc.assign(buffer, uuidsz); descsz = uuidsz; +#else // __MINGW32__ + UUID uuid; + typedef RPC_STATUS (RPC_ENTRY *UuidCreateFn)(UUID *Uuid); + + HMODULE rpc_library = LoadLibrary("rpcrt4.dll"); + if (!rpc_library) + gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll")); + else + { + UuidCreateFn uuid_create = reinterpret_cast( + GetProcAddress(rpc_library, "UuidCreate")); + if (!uuid_create) + gold_error(_("--build-id=uuid failed: could not find UuidCreate")); + else if (uuid_create(&uuid) != RPC_S_OK) + gold_error(_("__build_id=uuid failed: call UuidCreate() failed")); + FreeLibrary(rpc_library); + } + desc.assign(reinterpret_cast(&uuid), sizeof(UUID)); + descsz = sizeof(UUID); +#endif // __MINGW32__ } else if (strncmp(style, "0x", 2) == 0) { @@ -2374,8 +3259,8 @@ Layout::create_incremental_info_sections(Symbol_table* symtab) const char* incremental_strtab_name = this->namepool_.add(".gnu_incremental_strtab", false, NULL); Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name, - elfcpp::SHT_STRTAB, 0, - ORDER_INVALID, false); + elfcpp::SHT_STRTAB, 0, + ORDER_INVALID, false); Output_data_strtab* strtab_data = new Output_data_strtab(incr->get_stringpool()); incremental_strtab_os->add_output_section_data(strtab_data); @@ -2393,7 +3278,7 @@ Layout::create_incremental_info_sections(Symbol_table* symtab) // Return whether SEG1 should be before SEG2 in the output file. This // is based entirely on the segment type and flags. When this is -// called the segment addresses has normally not yet been set. +// called the segment addresses have normally not yet been set. bool Layout::segment_precedes(const Output_segment* seg1, @@ -2454,12 +3339,14 @@ Layout::segment_precedes(const Output_segment* seg1, // The order of non-PT_LOAD segments is unimportant. We simply sort // by the numeric segment type and flags values. There should not - // be more than one segment with the same type and flags. + // be more than one segment with the same type and flags, except + // when a linker script specifies such. if (type1 != elfcpp::PT_LOAD) { if (type1 != type2) return type1 < type2; - gold_assert(flags1 != flags2); + gold_assert(flags1 != flags2 + || this->script_options_->saw_phdrs_clause()); return flags1 < flags2; } @@ -2519,8 +3406,13 @@ Layout::segment_precedes(const Output_segment* seg1, return (flags1 & elfcpp::PF_R) == 0; // We shouldn't get here--we shouldn't create segments which we - // can't distinguish. - gold_unreachable(); + // can't distinguish. Unless of course we are using a weird linker + // script or overlapping --section-start options. We could also get + // here if plugins want unique segments for subsets of sections. + gold_assert(this->script_options_->saw_phdrs_clause() + || parameters->options().any_section_start() + || this->is_unique_segment_for_sections_specified()); + return false; } // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE. @@ -2536,6 +3428,20 @@ align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize) return aligned_off; } +// On targets where the text segment contains only executable code, +// a non-executable segment is never the text segment. + +static inline bool +is_text_segment(const Target* target, const Output_segment* seg) +{ + elfcpp::Elf_Xword flags = seg->flags(); + if ((flags & elfcpp::PF_W) != 0) + return false; + if ((flags & elfcpp::PF_X) == 0) + return !target->isolate_execinstr(); + return true; +} + // Set the file offsets of all the segments, and all the sections they // contain. They have all been created. LOAD_SEG must be be laid out // first. Return the offset of the data to follow. @@ -2544,19 +3450,23 @@ off_t Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, unsigned int* pshndx) { - // Sort them into the final order. - std::sort(this->segment_list_.begin(), this->segment_list_.end(), - Layout::Compare_segments()); + // Sort them into the final order. We use a stable sort so that we + // don't randomize the order of indistinguishable segments created + // by linker scripts. + std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(), + Layout::Compare_segments(this)); // Find the PT_LOAD segments, and set their addresses and offsets // and their section's addresses and offsets. - uint64_t addr; + uint64_t start_addr; if (parameters->options().user_set_Ttext()) - addr = parameters->options().Ttext(); + start_addr = parameters->options().Ttext(); else if (parameters->options().output_is_position_independent()) - addr = 0; + start_addr = 0; else - addr = target->default_text_segment_address(); + start_addr = target->default_text_segment_address(); + + uint64_t addr = start_addr; off_t off = 0; // If LOAD_SEG is NULL, then the file header and segment headers @@ -2581,15 +3491,39 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, const bool check_sections = parameters->options().check_sections(); Output_segment* last_load_segment = NULL; + unsigned int shndx_begin = *pshndx; + unsigned int shndx_load_seg = *pshndx; + for (Segment_list::iterator p = this->segment_list_.begin(); p != this->segment_list_.end(); ++p) { if ((*p)->type() == elfcpp::PT_LOAD) { - if (load_seg != NULL && load_seg != *p) - gold_unreachable(); - load_seg = NULL; + if (target->isolate_execinstr()) + { + // When we hit the segment that should contain the + // file headers, reset the file offset so we place + // it and subsequent segments appropriately. + // We'll fix up the preceding segments below. + if (load_seg == *p) + { + if (off == 0) + load_seg = NULL; + else + { + off = 0; + shndx_load_seg = *pshndx; + } + } + } + else + { + // Verify that the file headers fall into the first segment. + if (load_seg != NULL && load_seg != *p) + gold_unreachable(); + load_seg = NULL; + } bool are_addresses_set = (*p)->are_addresses_set(); if (are_addresses_set) @@ -2598,6 +3532,18 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, // the physical address. addr = (*p)->paddr(); } + else if (parameters->options().user_set_Ttext() + && (parameters->options().omagic() + || is_text_segment(target, *p))) + { + are_addresses_set = true; + } + else if (parameters->options().user_set_Trodata_segment() + && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0) + { + addr = parameters->options().Trodata_segment(); + are_addresses_set = true; + } else if (parameters->options().user_set_Tdata() && ((*p)->flags() & elfcpp::PF_W) != 0 && (!parameters->options().user_set_Tbss() @@ -2623,7 +3569,7 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, if (!parameters->options().nmagic() && !parameters->options().omagic()) - (*p)->set_minimum_p_align(common_pagesize); + (*p)->set_minimum_p_align(abi_pagesize); if (!are_addresses_set) { @@ -2633,19 +3579,51 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, // put them on different pages in memory. We will revisit this // decision once we know the size of the segment. - addr = align_address(addr, (*p)->maximum_alignment()); + uint64_t max_align = (*p)->maximum_alignment(); + if (max_align > abi_pagesize) + addr = align_address(addr, max_align); aligned_addr = addr; - if ((addr & (abi_pagesize - 1)) != 0) - addr = addr + abi_pagesize; + if (load_seg == *p) + { + // This is the segment that will contain the file + // headers, so its offset will have to be exactly zero. + gold_assert(orig_off == 0); + + // If the target wants a fixed minimum distance from the + // text segment to the read-only segment, move up now. + uint64_t min_addr = + start_addr + (parameters->options().user_set_rosegment_gap() + ? parameters->options().rosegment_gap() + : target->rosegment_gap()); + if (addr < min_addr) + addr = min_addr; + + // But this is not the first segment! To make its + // address congruent with its offset, that address better + // be aligned to the ABI-mandated page size. + addr = align_address(addr, abi_pagesize); + aligned_addr = addr; + } + else + { + if ((addr & (abi_pagesize - 1)) != 0) + addr = addr + abi_pagesize; - off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1)); + off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1)); + } } if (!parameters->options().nmagic() && !parameters->options().omagic()) - off = align_file_offset(off, addr, abi_pagesize); - else if (load_seg == NULL) + { + // Here we are also taking care of the case when + // the maximum segment alignment is larger than the page size. + off = align_file_offset(off, addr, + std::max(abi_pagesize, + (*p)->maximum_alignment())); + } + else { // This is -N or -n with a section script which prevents // us from using a load segment. We need to ensure that @@ -2661,10 +3639,11 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, unsigned int shndx_hold = *pshndx; bool has_relro = false; - uint64_t new_addr = (*p)->set_section_addresses(this, false, addr, - increase_relro, + uint64_t new_addr = (*p)->set_section_addresses(target, this, + false, addr, + &increase_relro, &has_relro, - &off, pshndx); + &off, pshndx); // Now that we know the size of this segment, we may be able // to save a page in memory, at the cost of wasting some @@ -2674,7 +3653,10 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, // aligned so that the relro data ends at a page boundary, // we do not try to realign it. - if (!are_addresses_set && !has_relro && aligned_addr != addr) + if (!are_addresses_set + && !has_relro + && aligned_addr != addr + && !parameters->incremental()) { uint64_t first_off = (common_pagesize - (aligned_addr @@ -2689,12 +3671,21 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, *pshndx = shndx_hold; addr = align_address(aligned_addr, common_pagesize); addr = align_address(addr, (*p)->maximum_alignment()); + if ((addr & (abi_pagesize - 1)) != 0) + addr = addr + abi_pagesize; off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1)); off = align_file_offset(off, addr, abi_pagesize); - new_addr = (*p)->set_section_addresses(this, true, addr, - increase_relro, + + increase_relro = this->increase_relro_; + if (this->script_options_->saw_sections_clause()) + increase_relro = 0; + has_relro = false; + + new_addr = (*p)->set_section_addresses(target, this, + true, addr, + &increase_relro, &has_relro, - &off, pshndx); + &off, pshndx); } } @@ -2717,8 +3708,42 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, lb1, le1, lb2, le2); } } - last_load_segment = *p; + last_load_segment = *p; + } + } + + if (load_seg != NULL && target->isolate_execinstr()) + { + // Process the early segments again, setting their file offsets + // so they land after the segments starting at LOAD_SEG. + off = align_file_offset(off, 0, target->abi_pagesize()); + + this->reset_relax_output(); + + for (Segment_list::iterator p = this->segment_list_.begin(); + *p != load_seg; + ++p) + { + if ((*p)->type() == elfcpp::PT_LOAD) + { + // We repeat the whole job of assigning addresses and + // offsets, but we really only want to change the offsets and + // must ensure that the addresses all come out the same as + // they did the first time through. + bool has_relro = false; + const uint64_t old_addr = (*p)->vaddr(); + const uint64_t old_end = old_addr + (*p)->memsz(); + uint64_t new_addr = (*p)->set_section_addresses(target, this, + true, old_addr, + &increase_relro, + &has_relro, + &off, + &shndx_begin); + gold_assert(new_addr == old_end); + } } + + gold_assert(shndx_begin == shndx_load_seg); } // Handle the non-PT_LOAD segments, setting their offsets from their @@ -2727,7 +3752,9 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, p != this->segment_list_.end(); ++p) { - if ((*p)->type() != elfcpp::PT_LOAD) + // PT_GNU_STACK was set up correctly when it was created. + if ((*p)->type() != elfcpp::PT_LOAD + && (*p)->type() != elfcpp::PT_GNU_STACK) (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO ? increase_relro : 0); @@ -2770,7 +3797,8 @@ Layout::set_relocatable_section_offsets(Output_data* file_header, (*p)->set_address(0); (*p)->set_file_offset(off); (*p)->finalize_data_size(); - off += (*p)->data_size(); + if ((*p)->type() != elfcpp::SHT_NOBITS) + off += (*p)->data_size(); (*p)->set_out_shndx(*pshndx); ++*pshndx; @@ -2785,6 +3813,9 @@ Layout::set_relocatable_section_offsets(Output_data* file_header, off_t Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass) { + off_t startoff = off; + off_t maxoff = off; + for (Section_list::iterator p = this->unattached_section_list_.begin(); p != this->unattached_section_list_.end(); ++p) @@ -2805,27 +3836,64 @@ Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass) } if (pass == BEFORE_INPUT_SECTIONS_PASS - && (*p)->after_input_sections()) - continue; + && (*p)->after_input_sections()) + continue; else if (pass == POSTPROCESSING_SECTIONS_PASS - && (!(*p)->after_input_sections() - || (*p)->type() == elfcpp::SHT_STRTAB)) - continue; + && (!(*p)->after_input_sections() + || (*p)->type() == elfcpp::SHT_STRTAB)) + continue; else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS - && (!(*p)->after_input_sections() - || (*p)->type() != elfcpp::SHT_STRTAB)) - continue; + && (!(*p)->after_input_sections() + || (*p)->type() != elfcpp::SHT_STRTAB)) + continue; + + if (!parameters->incremental_update()) + { + off = align_address(off, (*p)->addralign()); + (*p)->set_file_offset(off); + (*p)->finalize_data_size(); + } + else + { + // Incremental update: allocate file space from free list. + (*p)->pre_finalize_data_size(); + off_t current_size = (*p)->current_data_size(); + off = this->allocate(current_size, (*p)->addralign(), startoff); + if (off == -1) + { + if (is_debugging_enabled(DEBUG_INCREMENTAL)) + this->free_list_.dump(); + gold_assert((*p)->output_section() != NULL); + gold_fallback(_("out of patch space for section %s; " + "relink with --incremental-full"), + (*p)->output_section()->name()); + } + (*p)->set_file_offset(off); + (*p)->finalize_data_size(); + if ((*p)->data_size() > current_size) + { + gold_assert((*p)->output_section() != NULL); + gold_fallback(_("%s: section changed size; " + "relink with --incremental-full"), + (*p)->output_section()->name()); + } + gold_debug(DEBUG_INCREMENTAL, + "set_section_offsets: %08lx %08lx %s", + static_cast(off), + static_cast((*p)->data_size()), + ((*p)->output_section() != NULL + ? (*p)->output_section()->name() : "(special)")); + } - off = align_address(off, (*p)->addralign()); - (*p)->set_file_offset(off); - (*p)->finalize_data_size(); off += (*p)->data_size(); + if (off > maxoff) + maxoff = off; // At this point the name must be set. if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS) this->namepool_.add((*p)->name(), false, NULL); } - return off; + return maxoff; } // Set the section indexes of all the sections not associated with a @@ -2939,9 +4007,8 @@ Layout::create_symtab_sections(const Input_objects* input_objects, else gold_unreachable(); - off_t off = *poff; - off = align_address(off, align); - off_t startoff = off; + // Compute file offsets relative to the start of the symtab section. + off_t off = 0; // Save space for the dummy symbol at the start of the section. We // never bother to write this out--it will just be left as zero. @@ -2968,13 +4035,13 @@ Layout::create_symtab_sections(const Input_objects* input_objects, ++p) { unsigned int index = (*p)->finalize_local_symbols(local_symbol_index, - off, symtab); + off, symtab); off += (index - local_symbol_index) * symsize; local_symbol_index = index; } unsigned int local_symcount = local_symbol_index; - gold_assert(static_cast(local_symcount * symsize) == off - startoff); + gold_assert(static_cast(local_symcount * symsize) == off); off_t dynoff; size_t dyn_global_index; @@ -2995,6 +4062,7 @@ Layout::create_symtab_sections(const Input_objects* input_objects, == this->dynsym_section_->data_size() - locsize); } + off_t global_off = off; off = symtab->finalize(off, dynoff, dyn_global_index, dyncount, &this->sympool_, &local_symcount); @@ -3009,8 +4077,7 @@ Layout::create_symtab_sections(const Input_objects* input_objects, false); this->symtab_section_ = osymtab; - Output_section_data* pos = new Output_data_fixed_space(off - startoff, - align, + Output_section_data* pos = new Output_data_fixed_space(off, align, "** symtab"); osymtab->add_output_section_data(pos); @@ -3030,7 +4097,7 @@ Layout::create_symtab_sections(const Input_objects* input_objects, elfcpp::SHT_SYMTAB_SHNDX, 0, ORDER_INVALID, false); - size_t symcount = (off - startoff) / symsize; + size_t symcount = off / symsize; this->symtab_xindex_ = new Output_symtab_xindex(symcount); osymtab_xindex->add_output_section_data(this->symtab_xindex_); @@ -3056,13 +4123,30 @@ Layout::create_symtab_sections(const Input_objects* input_objects, Output_section_data* pstr = new Output_data_strtab(&this->sympool_); ostrtab->add_output_section_data(pstr); - osymtab->set_file_offset(startoff); + off_t symtab_off; + if (!parameters->incremental_update()) + symtab_off = align_address(*poff, align); + else + { + symtab_off = this->allocate(off, align, *poff); + if (off == -1) + gold_fallback(_("out of patch space for symbol table; " + "relink with --incremental-full")); + gold_debug(DEBUG_INCREMENTAL, + "create_symtab_sections: %08lx %08lx .symtab", + static_cast(symtab_off), + static_cast(off)); + } + + symtab->set_file_offset(symtab_off + global_off); + osymtab->set_file_offset(symtab_off); osymtab->finalize_data_size(); osymtab->set_link_section(ostrtab); osymtab->set_info(local_symcount); osymtab->set_entsize(symsize); - *poff = off; + if (symtab_off + off > *poff) + *poff = symtab_off + off; } } @@ -3109,10 +4193,25 @@ Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff) &this->unattached_section_list_, &this->namepool_, shstrtab_section); - off_t off = align_address(*poff, oshdrs->addralign()); + off_t off; + if (!parameters->incremental_update()) + off = align_address(*poff, oshdrs->addralign()); + else + { + oshdrs->pre_finalize_data_size(); + off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff); + if (off == -1) + gold_fallback(_("out of patch space for section header table; " + "relink with --incremental-full")); + gold_debug(DEBUG_INCREMENTAL, + "create_shdrs: %08lx %08lx (section header table)", + static_cast(off), + static_cast(off + oshdrs->data_size())); + } oshdrs->set_address_and_file_offset(0, off); off += oshdrs->data_size(); - *poff = off; + if (off > *poff) + *poff = off; this->section_headers_ = oshdrs; } @@ -3133,7 +4232,7 @@ Layout::allocated_output_section_count() const void Layout::create_dynamic_symtab(const Input_objects* input_objects, - Symbol_table* symtab, + Symbol_table* symtab, Output_section** pdynstr, unsigned int* plocal_dynamic_count, std::vector* pdynamic_symbols, @@ -3200,20 +4299,27 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, ORDER_DYNAMIC_LINKER, false); - Output_section_data* odata = new Output_data_fixed_space(index * symsize, - align, - "** dynsym"); - dynsym->add_output_section_data(odata); + // Check for NULL as a linker script may discard .dynsym. + if (dynsym != NULL) + { + Output_section_data* odata = new Output_data_fixed_space(index * symsize, + align, + "** dynsym"); + dynsym->add_output_section_data(odata); - dynsym->set_info(local_symcount); - dynsym->set_entsize(symsize); - dynsym->set_addralign(align); + dynsym->set_info(local_symcount); + dynsym->set_entsize(symsize); + dynsym->set_addralign(align); - this->dynsym_section_ = dynsym; + this->dynsym_section_ = dynsym; + } Output_data_dynamic* const odyn = this->dynamic_data_; - odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym); - odyn->add_constant(elfcpp::DT_SYMENT, symsize); + if (odyn != NULL) + { + odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym); + odyn->add_constant(elfcpp::DT_SYMENT, symsize); + } // If there are more than SHN_LORESERVE allocated sections, we // create a .dynsym_shndx section. It is possible that we don't @@ -3230,20 +4336,23 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, elfcpp::SHF_ALLOC, false, ORDER_DYNAMIC_LINKER, false); - this->dynsym_xindex_ = new Output_symtab_xindex(index); + if (dynsym_xindex != NULL) + { + this->dynsym_xindex_ = new Output_symtab_xindex(index); - dynsym_xindex->add_output_section_data(this->dynsym_xindex_); + dynsym_xindex->add_output_section_data(this->dynsym_xindex_); - dynsym_xindex->set_link_section(dynsym); - dynsym_xindex->set_addralign(4); - dynsym_xindex->set_entsize(4); + dynsym_xindex->set_link_section(dynsym); + dynsym_xindex->set_addralign(4); + dynsym_xindex->set_entsize(4); - dynsym_xindex->set_after_input_sections(); + dynsym_xindex->set_after_input_sections(); - // This tells the driver code to wait until the symbol table has - // written out before writing out the postprocessing sections, - // including the .dynsym_shndx section. - this->any_postprocessing_sections_ = true; + // This tells the driver code to wait until the symbol table + // has written out before writing out the postprocessing + // sections, including the .dynsym_shndx section. + this->any_postprocessing_sections_ = true; + } } // Create the dynamic string table section. @@ -3254,30 +4363,38 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, false, ORDER_DYNAMIC_LINKER, false); + *pdynstr = dynstr; + if (dynstr != NULL) + { + Output_section_data* strdata = new Output_data_strtab(&this->dynpool_); + dynstr->add_output_section_data(strdata); - Output_section_data* strdata = new Output_data_strtab(&this->dynpool_); - dynstr->add_output_section_data(strdata); - - dynsym->set_link_section(dynstr); - this->dynamic_section_->set_link_section(dynstr); - - odyn->add_section_address(elfcpp::DT_STRTAB, dynstr); - odyn->add_section_size(elfcpp::DT_STRSZ, dynstr); + if (dynsym != NULL) + dynsym->set_link_section(dynstr); + if (this->dynamic_section_ != NULL) + this->dynamic_section_->set_link_section(dynstr); - *pdynstr = dynstr; + if (odyn != NULL) + { + odyn->add_section_address(elfcpp::DT_STRTAB, dynstr); + odyn->add_section_size(elfcpp::DT_STRSZ, dynstr); + } + } - // Create the hash tables. + // Create the hash tables. The Gnu-style hash table must be + // built first, because it changes the order of the symbols + // in the dynamic symbol table. - if (strcmp(parameters->options().hash_style(), "sysv") == 0 + if (strcmp(parameters->options().hash_style(), "gnu") == 0 || strcmp(parameters->options().hash_style(), "both") == 0) { unsigned char* phash; unsigned int hashlen; - Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount, + Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount, &phash, &hashlen); Output_section* hashsec = - this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH, + this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH, elfcpp::SHF_ALLOC, false, ORDER_DYNAMIC_LINKER, false); @@ -3285,24 +4402,35 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, hashlen, align, "** hash"); - hashsec->add_output_section_data(hashdata); + if (hashsec != NULL && hashdata != NULL) + hashsec->add_output_section_data(hashdata); + + if (hashsec != NULL) + { + if (dynsym != NULL) + hashsec->set_link_section(dynsym); - hashsec->set_link_section(dynsym); - hashsec->set_entsize(4); + // For a 64-bit target, the entries in .gnu.hash do not have + // a uniform size, so we only set the entry size for a + // 32-bit target. + if (parameters->target().get_size() == 32) + hashsec->set_entsize(4); - odyn->add_section_address(elfcpp::DT_HASH, hashsec); + if (odyn != NULL) + odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec); + } } - if (strcmp(parameters->options().hash_style(), "gnu") == 0 + if (strcmp(parameters->options().hash_style(), "sysv") == 0 || strcmp(parameters->options().hash_style(), "both") == 0) { unsigned char* phash; unsigned int hashlen; - Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount, + Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount, &phash, &hashlen); Output_section* hashsec = - this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH, + this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH, elfcpp::SHF_ALLOC, false, ORDER_DYNAMIC_LINKER, false); @@ -3310,17 +4438,18 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, hashlen, align, "** hash"); - hashsec->add_output_section_data(hashdata); - - hashsec->set_link_section(dynsym); + if (hashsec != NULL && hashdata != NULL) + hashsec->add_output_section_data(hashdata); - // For a 64-bit target, the entries in .gnu.hash do not have a - // uniform size, so we only set the entry size for a 32-bit - // target. - if (parameters->target().get_size() == 32) - hashsec->set_entsize(4); + if (hashsec != NULL) + { + if (dynsym != NULL) + hashsec->set_link_section(dynsym); + hashsec->set_entsize(parameters->target().hash_entry_size() / 8); + } - odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec); + if (odyn != NULL) + odyn->add_section_address(elfcpp::DT_HASH, hashsec); } } @@ -3330,7 +4459,8 @@ void Layout::assign_local_dynsym_offsets(const Input_objects* input_objects) { Output_section* dynsym = this->dynsym_section_; - gold_assert(dynsym != NULL); + if (dynsym == NULL) + return; off_t off = dynsym->offset(); @@ -3411,46 +4541,59 @@ Layout::sized_create_version_sections( ORDER_DYNAMIC_LINKER, false); - unsigned char* vbuf; - unsigned int vsize; - versions->symbol_section_contents(symtab, &this->dynpool_, - local_symcount, - dynamic_symbols, - &vbuf, &vsize); - - Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2, - "** versions"); - - vsec->add_output_section_data(vdata); - vsec->set_entsize(2); - vsec->set_link_section(this->dynsym_section_); + // Check for NULL since a linker script may discard this section. + if (vsec != NULL) + { + unsigned char* vbuf; + unsigned int vsize; + versions->symbol_section_contents(symtab, + &this->dynpool_, + local_symcount, + dynamic_symbols, + &vbuf, &vsize); + + Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2, + "** versions"); + + vsec->add_output_section_data(vdata); + vsec->set_entsize(2); + vsec->set_link_section(this->dynsym_section_); + } Output_data_dynamic* const odyn = this->dynamic_data_; - odyn->add_section_address(elfcpp::DT_VERSYM, vsec); + if (odyn != NULL && vsec != NULL) + odyn->add_section_address(elfcpp::DT_VERSYM, vsec); if (versions->any_defs()) { Output_section* vdsec; - vdsec= this->choose_output_section(NULL, ".gnu.version_d", - elfcpp::SHT_GNU_verdef, - elfcpp::SHF_ALLOC, - false, ORDER_DYNAMIC_LINKER, false); + vdsec = this->choose_output_section(NULL, ".gnu.version_d", + elfcpp::SHT_GNU_verdef, + elfcpp::SHF_ALLOC, + false, ORDER_DYNAMIC_LINKER, false); - unsigned char* vdbuf; - unsigned int vdsize; - unsigned int vdentries; - versions->def_section_contents(&this->dynpool_, &vdbuf, - &vdsize, &vdentries); + if (vdsec != NULL) + { + unsigned char* vdbuf; + unsigned int vdsize; + unsigned int vdentries; + versions->def_section_contents(&this->dynpool_, + &vdbuf, &vdsize, + &vdentries); - Output_section_data* vddata = - new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs"); + Output_section_data* vddata = + new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs"); - vdsec->add_output_section_data(vddata); - vdsec->set_link_section(dynstr); - vdsec->set_info(vdentries); + vdsec->add_output_section_data(vddata); + vdsec->set_link_section(dynstr); + vdsec->set_info(vdentries); - odyn->add_section_address(elfcpp::DT_VERDEF, vdsec); - odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries); + if (odyn != NULL) + { + odyn->add_section_address(elfcpp::DT_VERDEF, vdsec); + odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries); + } + } } if (versions->any_needs()) @@ -3461,22 +4604,28 @@ Layout::sized_create_version_sections( elfcpp::SHF_ALLOC, false, ORDER_DYNAMIC_LINKER, false); - unsigned char* vnbuf; - unsigned int vnsize; - unsigned int vnentries; - versions->need_section_contents(&this->dynpool_, - &vnbuf, &vnsize, - &vnentries); + if (vnsec != NULL) + { + unsigned char* vnbuf; + unsigned int vnsize; + unsigned int vnentries; + versions->need_section_contents(&this->dynpool_, + &vnbuf, &vnsize, + &vnentries); - Output_section_data* vndata = - new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs"); + Output_section_data* vndata = + new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs"); - vnsec->add_output_section_data(vndata); - vnsec->set_link_section(dynstr); - vnsec->set_info(vnentries); + vnsec->add_output_section_data(vndata); + vnsec->set_link_section(dynstr); + vnsec->set_info(vnentries); - odyn->add_section_address(elfcpp::DT_VERNEED, vnsec); - odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries); + if (odyn != NULL) + { + odyn->add_section_address(elfcpp::DT_VERNEED, vnsec); + odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries); + } + } } } @@ -3485,6 +4634,8 @@ Layout::sized_create_version_sections( void Layout::create_interp(const Target* target) { + gold_assert(this->interp_segment_ == NULL); + const char* interp = parameters->options().dynamic_linker(); if (interp == NULL) { @@ -3501,14 +4652,8 @@ Layout::create_interp(const Target* target) elfcpp::SHF_ALLOC, false, ORDER_INTERP, false); - osec->add_output_section_data(odata); - - if (!this->script_options_->saw_phdrs_clause()) - { - Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP, - elfcpp::PF_R); - oseg->add_output_section_to_nonload(osec, elfcpp::PF_R); - } + if (osec != NULL) + osec->add_output_section_data(odata); } // Add dynamic tags for the PLT and the dynamic relocs. This is @@ -3524,7 +4669,8 @@ Layout::create_interp(const Target* target) // some targets have multiple reloc sections in PLT_REL. // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA, -// DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. +// DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output +// section. // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an // executable. @@ -3550,16 +4696,26 @@ Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got, use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA); } - if (dyn_rel != NULL && dyn_rel->output_section() != NULL) + if ((dyn_rel != NULL && dyn_rel->output_section() != NULL) + || (dynrel_includes_plt + && plt_rel != NULL + && plt_rel->output_section() != NULL)) { + bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL; + bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL; odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA, - dyn_rel); - if (plt_rel != NULL && dynrel_includes_plt) - odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ, - dyn_rel, plt_rel); + (have_dyn_rel + ? dyn_rel->output_section() + : plt_rel->output_section())); + elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ; + if (have_dyn_rel && have_plt_rel && dynrel_includes_plt) + odyn->add_section_size(size_tag, + dyn_rel->output_section(), + plt_rel->output_section()); + else if (have_dyn_rel) + odyn->add_section_size(size_tag, dyn_rel->output_section()); else - odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ, - dyn_rel); + odyn->add_section_size(size_tag, plt_rel->output_section()); const int size = parameters->target().get_size(); elfcpp::DT rel_tag; int rel_size; @@ -3585,7 +4741,7 @@ Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got, } odyn->add_constant(rel_tag, rel_size); - if (parameters->options().combreloc()) + if (parameters->options().combreloc() && have_dyn_rel) { size_t c = dyn_rel->relative_reloc_count(); if (c > 0) @@ -3604,13 +4760,23 @@ Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got, } } +void +Layout::add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val) +{ + Output_data_dynamic* odyn = this->dynamic_data_; + if (odyn == NULL) + return; + odyn->add_constant(tag, val); +} + // Finish the .dynamic section and PT_DYNAMIC segment. void Layout::finish_dynamic_section(const Input_objects* input_objects, const Symbol_table* symtab) { - if (!this->script_options_->saw_phdrs_clause()) + if (!this->script_options_->saw_phdrs_clause() + && this->dynamic_section_ != NULL) { Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC, (elfcpp::PF_R @@ -3620,13 +4786,14 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, } Output_data_dynamic* const odyn = this->dynamic_data_; + if (odyn == NULL) + return; for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin(); p != input_objects->dynobj_end(); ++p) { - if (!(*p)->is_needed() - && (*p)->input_file()->options().as_needed()) + if (!(*p)->is_needed() && (*p)->as_needed()) { // This dynamic object was linked with --as-needed, but it // is not needed. @@ -3660,48 +4827,49 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, { case elfcpp::SHT_FINI_ARRAY: odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p); - odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p); + odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p); break; case elfcpp::SHT_INIT_ARRAY: odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p); - odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p); + odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p); break; case elfcpp::SHT_PREINIT_ARRAY: odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p); - odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p); + odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p); break; default: break; } - + // Add a DT_RPATH entry if needed. const General_options::Dir_list& rpath(parameters->options().rpath()); if (!rpath.empty()) { std::string rpath_val; for (General_options::Dir_list::const_iterator p = rpath.begin(); - p != rpath.end(); - ++p) - { - if (rpath_val.empty()) - rpath_val = p->name(); - else - { - // Eliminate duplicates. - General_options::Dir_list::const_iterator q; - for (q = rpath.begin(); q != p; ++q) + p != rpath.end(); + ++p) + { + if (rpath_val.empty()) + rpath_val = p->name(); + else + { + // Eliminate duplicates. + General_options::Dir_list::const_iterator q; + for (q = rpath.begin(); q != p; ++q) if (q->name() == p->name()) - break; - if (q == p) - { - rpath_val += ':'; - rpath_val += p->name(); - } - } - } - - odyn->add_string(elfcpp::DT_RPATH, rpath_val); - if (parameters->options().enable_new_dtags()) + break; + if (q == p) + { + rpath_val += ':'; + rpath_val += p->name(); + } + } + } + + if (!parameters->options().enable_new_dtags()) + odyn->add_string(elfcpp::DT_RPATH, rpath_val); + else odyn->add_string(elfcpp::DT_RUNPATH, rpath_val); } @@ -3710,16 +4878,17 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, if (!this->script_options_->saw_sections_clause()) { for (Segment_list::const_iterator p = this->segment_list_.begin(); - p != this->segment_list_.end(); - ++p) - { - if (((*p)->flags() & elfcpp::PF_W) == 0 - && (*p)->has_dynamic_reloc()) - { - have_textrel = true; - break; - } - } + p != this->segment_list_.end(); + ++p) + { + if ((*p)->type() == elfcpp::PT_LOAD + && ((*p)->flags() & elfcpp::PF_W) == 0 + && (*p)->has_dynamic_reloc()) + { + have_textrel = true; + break; + } + } } else { @@ -3728,21 +4897,31 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, // relocations. If those sections wind up in writable segments, // then we have created an unnecessary DT_TEXTREL entry. for (Section_list::const_iterator p = this->section_list_.begin(); - p != this->section_list_.end(); - ++p) - { - if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0 - && ((*p)->flags() & elfcpp::SHF_WRITE) == 0 - && ((*p)->has_dynamic_reloc())) - { - have_textrel = true; - break; - } - } - } - - // Add a DT_FLAGS entry. We add it even if no flags are set so that - // post-link tools can easily modify these flags if desired. + p != this->section_list_.end(); + ++p) + { + if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0 + && ((*p)->flags() & elfcpp::SHF_WRITE) == 0 + && (*p)->has_dynamic_reloc()) + { + have_textrel = true; + break; + } + } + } + + if (parameters->options().filter() != NULL) + odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter()); + if (parameters->options().any_auxiliary()) + { + for (options::String_set::const_iterator p = + parameters->options().auxiliary_begin(); + p != parameters->options().auxiliary_end(); + ++p) + odyn->add_string(elfcpp::DT_AUXILIARY, *p); + } + + // Add a DT_FLAGS entry if necessary. unsigned int flags = 0; if (have_textrel) { @@ -3760,7 +4939,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, flags |= elfcpp::DF_STATIC_TLS; if (parameters->options().origin()) flags |= elfcpp::DF_ORIGIN; - if (parameters->options().Bsymbolic()) + if (parameters->options().Bsymbolic() + && !parameters->options().have_dynamic_list()) { flags |= elfcpp::DF_SYMBOLIC; // Add DT_SYMBOLIC for compatibility with older loaders. @@ -3768,9 +4948,12 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, } if (parameters->options().now()) flags |= elfcpp::DF_BIND_NOW; - odyn->add_constant(elfcpp::DT_FLAGS, flags); + if (flags != 0) + odyn->add_constant(elfcpp::DT_FLAGS, flags); flags = 0; + if (parameters->options().global()) + flags |= elfcpp::DF_1_GLOBAL; if (parameters->options().initfirst()) flags |= elfcpp::DF_1_INITFIRST; if (parameters->options().interpose()) @@ -3793,7 +4976,9 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, flags |= elfcpp::DF_1_ORIGIN; if (parameters->options().now()) flags |= elfcpp::DF_1_NOW; - if (flags) + if (parameters->options().Bgroup()) + flags |= elfcpp::DF_1_GROUP; + if (flags != 0) odyn->add_constant(elfcpp::DT_FLAGS_1, flags); } @@ -3804,7 +4989,11 @@ void Layout::set_dynamic_symbol_size(const Symbol_table* symtab) { Output_data_dynamic* const odyn = this->dynamic_data_; + if (odyn == NULL) + return; odyn->finalize_data_size(); + if (this->dynamic_symbol_ == NULL) + return; off_t data_size = odyn->data_size(); const int size = parameters->target().get_size(); if (size == 32) @@ -3821,14 +5010,15 @@ Layout::set_dynamic_symbol_size(const Symbol_table* symtab) // based on the GNU linker default ELF linker script. #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 } +#define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 } const Layout::Section_name_mapping Layout::section_name_mapping[] = { MAPPING_INIT(".text.", ".text"), - MAPPING_INIT(".ctors.", ".ctors"), - MAPPING_INIT(".dtors.", ".dtors"), MAPPING_INIT(".rodata.", ".rodata"), - MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"), - MAPPING_INIT(".data.rel.ro", ".data.rel.ro"), + MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"), + MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"), + MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"), + MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"), MAPPING_INIT(".data.", ".data"), MAPPING_INIT(".bss.", ".bss"), MAPPING_INIT(".tdata.", ".tdata"), @@ -3867,6 +5057,7 @@ const Layout::Section_name_mapping Layout::section_name_mapping[] = MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"), }; #undef MAPPING_INIT +#undef MAPPING_INIT_EXACT const int Layout::section_name_mapping_count = (sizeof(Layout::section_name_mapping) @@ -3877,7 +5068,8 @@ const int Layout::section_name_mapping_count = // length of NAME. const char* -Layout::output_section_name(const char* name, size_t* plen) +Layout::output_section_name(const Relobj* relobj, const char* name, + size_t* plen) { // gcc 4.3 generates the following sorts of section names when it // needs a section name specific to a function: @@ -3917,30 +5109,80 @@ Layout::output_section_name(const char* name, size_t* plen) const Section_name_mapping* psnm = section_name_mapping; for (int i = 0; i < section_name_mapping_count; ++i, ++psnm) { - if (strncmp(name, psnm->from, psnm->fromlen) == 0) + if (psnm->fromlen > 0) + { + if (strncmp(name, psnm->from, psnm->fromlen) == 0) + { + *plen = psnm->tolen; + return psnm->to; + } + } + else { - *plen = psnm->tolen; - return psnm->to; + if (strcmp(name, psnm->from) == 0) + { + *plen = psnm->tolen; + return psnm->to; + } } } - // Compressed debug sections should be mapped to the corresponding - // uncompressed section. - if (is_compressed_debug_section(name)) + // As an additional complication, .ctors sections are output in + // either .ctors or .init_array sections, and .dtors sections are + // output in either .dtors or .fini_array sections. + if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name)) { - size_t len = strlen(name); - char* uncompressed_name = new char[len]; - uncompressed_name[0] = '.'; - gold_assert(name[0] == '.' && name[1] == 'z'); - strncpy(&uncompressed_name[1], &name[2], len - 2); - uncompressed_name[len - 1] = '\0'; - *plen = len - 1; - return uncompressed_name; + if (parameters->options().ctors_in_init_array()) + { + *plen = 11; + return name[1] == 'c' ? ".init_array" : ".fini_array"; + } + else + { + *plen = 6; + return name[1] == 'c' ? ".ctors" : ".dtors"; + } + } + if (parameters->options().ctors_in_init_array() + && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0)) + { + // To make .init_array/.fini_array work with gcc we must exclude + // .ctors and .dtors sections from the crtbegin and crtend + // files. + if (relobj == NULL + || (!Layout::match_file_name(relobj, "crtbegin") + && !Layout::match_file_name(relobj, "crtend"))) + { + *plen = 11; + return name[1] == 'c' ? ".init_array" : ".fini_array"; + } } return name; } +// Return true if RELOBJ is an input file whose base name matches +// FILE_NAME. The base name must have an extension of ".o", and must +// be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is +// to match crtbegin.o as well as crtbeginS.o without getting confused +// by other possibilities. Overall matching the file name this way is +// a dreadful hack, but the GNU linker does it in order to better +// support gcc, and we need to be compatible. + +bool +Layout::match_file_name(const Relobj* relobj, const char* match) +{ + const std::string& file_name(relobj->name()); + const char* base_name = lbasename(file_name.c_str()); + size_t match_len = strlen(match); + if (strncmp(base_name, match, match_len) != 0) + return false; + size_t base_len = strlen(base_name); + if (base_len != match_len + 2 && base_len != match_len + 3) + return false; + return memcmp(base_name + base_len - 2, ".o", 2) == 0; +} + // Check if a comdat group or .gnu.linkonce section with the given // NAME is selected for the link. If there is already a section, // *KEPT_SECTION is set to point to the existing section and the @@ -3955,7 +5197,7 @@ Layout::find_or_add_kept_section(const std::string& name, unsigned int shndx, bool is_comdat, bool is_group_name, - Kept_section** kept_section) + Kept_section** kept_section) { // It's normal to see a couple of entries here, for the x86 thunk // sections. If we see more than a few, we're linking a C++ @@ -3994,12 +5236,12 @@ Layout::find_or_add_kept_section(const std::string& name, // If the kept group is from a plugin object, and we're in the // replacement phase, accept the new one as a replacement. if (ins.first->second.object() == NULL - && parameters->options().plugins()->in_replacement_phase()) - { + && parameters->options().plugins()->in_replacement_phase()) + { ins.first->second.set_object(object); ins.first->second.set_shndx(shndx); - return true; - } + return true; + } return false; } else if (is_group_name) @@ -4031,6 +5273,19 @@ Layout::get_allocated_sections(Section_list* section_list) const section_list->push_back(*p); } +// Store the executable sections into the section list. + +void +Layout::get_executable_sections(Section_list* section_list) const +{ + for (Section_list::const_iterator p = this->section_list_.begin(); + p != this->section_list_.end(); + ++p) + if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR)) + == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR)) + section_list->push_back(*p); +} + // Create an output segment. Output_segment* @@ -4044,10 +5299,33 @@ Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags) this->tls_segment_ = oseg; else if (type == elfcpp::PT_GNU_RELRO) this->relro_segment_ = oseg; + else if (type == elfcpp::PT_INTERP) + this->interp_segment_ = oseg; return oseg; } +// Return the file offset of the normal symbol table. + +off_t +Layout::symtab_section_offset() const +{ + if (this->symtab_section_ != NULL) + return this->symtab_section_->offset(); + return 0; +} + +// Return the section index of the normal symbol table. It may have +// been stripped by the -s/--strip-all option. + +unsigned int +Layout::symtab_section_shndx() const +{ + if (this->symtab_section_ != NULL) + return this->symtab_section_->out_shndx(); + return 0; +} + // Write out the Output_sections. Most won't have anything to write, // since most of the data will come from input sections which are // handled elsewhere. But some Output_sections do have Output_data. @@ -4109,6 +5387,13 @@ Layout::write_data(const Symbol_table* symtab, Output_file* of) const p != this->special_output_list_.end(); ++p) (*p)->write(of); + + // Write out the Output_data which are not in an Output_section + // and are regenerated in each iteration of relaxation. + for (Data_list::const_iterator p = this->relax_output_list_.begin(); + p != this->relax_output_list_.end(); + ++p) + (*p)->write(of); } // Write out the Output_sections which can only be written after the @@ -4149,44 +5434,49 @@ Layout::write_sections_after_input_sections(Output_file* of) this->section_headers_->write(of); } -// If the build ID requires computing a checksum, do so here, and -// write it out. We compute a checksum over the entire file because -// that is simplest. +// If a tree-style build ID was requested, the parallel part of that computation +// is already done, and the final hash-of-hashes is computed here. For other +// types of build IDs, all the work is done here. void -Layout::write_build_id(Output_file* of) const +Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes, + size_t size_of_hashes) const { if (this->build_id_note_ == NULL) return; - const unsigned char* iv = of->get_input_view(0, this->output_file_size_); - unsigned char* ov = of->get_output_view(this->build_id_note_->offset(), this->build_id_note_->data_size()); - const char* style = parameters->options().build_id(); - if (strcmp(style, "sha1") == 0) + if (array_of_hashes == NULL) { - sha1_ctx ctx; - sha1_init_ctx(&ctx); - sha1_process_bytes(iv, this->output_file_size_, &ctx); - sha1_finish_ctx(&ctx, ov); + const size_t output_file_size = this->output_file_size(); + const unsigned char* iv = of->get_input_view(0, output_file_size); + const char* style = parameters->options().build_id(); + + // If we get here with style == "tree" then the output must be + // too small for chunking, and we use SHA-1 in that case. + if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0)) + sha1_buffer(reinterpret_cast(iv), output_file_size, ov); + else if (strcmp(style, "md5") == 0) + md5_buffer(reinterpret_cast(iv), output_file_size, ov); + else + gold_unreachable(); + + of->free_input_view(0, output_file_size, iv); } - else if (strcmp(style, "md5") == 0) + else { - md5_ctx ctx; - md5_init_ctx(&ctx); - md5_process_bytes(iv, this->output_file_size_, &ctx); - md5_finish_ctx(&ctx, ov); + // Non-overlapping substrings of the output file have been hashed. + // Compute SHA-1 hash of the hashes. + sha1_buffer(reinterpret_cast(array_of_hashes), + size_of_hashes, ov); + delete[] array_of_hashes; } - else - gold_unreachable(); of->write_output_view(this->build_id_note_->offset(), this->build_id_note_->data_size(), ov); - - of->free_input_view(0, this->output_file_size_, iv); } // Write out a binary file. This is called after the link is @@ -4247,6 +5537,10 @@ Layout::print_to_mapfile(Mapfile* mapfile) const p != this->segment_list_.end(); ++p) (*p)->print_sections_to_mapfile(mapfile); + for (Section_list::const_iterator p = this->unattached_section_list_.begin(); + p != this->unattached_section_list_.end(); + ++p) + (*p)->print_to_mapfile(mapfile); } // Print statistical information to stderr. This is used for --stats. @@ -4281,6 +5575,8 @@ void Write_sections_task::locks(Task_locker* tl) { tl->add(this, this->output_sections_blocker_); + if (this->input_sections_blocker_ != NULL) + tl->add(this, this->input_sections_blocker_); tl->add(this, this->final_blocker_); } @@ -4374,15 +5670,69 @@ Write_after_input_sections_task::run(Workqueue*) this->layout_->write_sections_after_input_sections(this->of_); } +// Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes, +// or as a "tree" where each chunk of the string is hashed and then those +// hashes are put into a (much smaller) string which is hashed with sha1. +// We compute a checksum over the entire file because that is simplest. + +void +Build_id_task_runner::run(Workqueue* workqueue, const Task*) +{ + Task_token* post_hash_tasks_blocker = new Task_token(true); + const Layout* layout = this->layout_; + Output_file* of = this->of_; + const size_t filesize = (layout->output_file_size() <= 0 ? 0 + : static_cast(layout->output_file_size())); + unsigned char* array_of_hashes = NULL; + size_t size_of_hashes = 0; + + if (strcmp(this->options_->build_id(), "tree") == 0 + && this->options_->build_id_chunk_size_for_treehash() > 0 + && filesize > 0 + && (filesize >= this->options_->build_id_min_file_size_for_treehash())) + { + static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16; + const size_t chunk_size = + this->options_->build_id_chunk_size_for_treehash(); + const size_t num_hashes = ((filesize - 1) / chunk_size) + 1; + post_hash_tasks_blocker->add_blockers(num_hashes); + size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES; + array_of_hashes = new unsigned char[size_of_hashes]; + unsigned char *dst = array_of_hashes; + for (size_t i = 0, src_offset = 0; i < num_hashes; + i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size) + { + size_t size = std::min(chunk_size, filesize - src_offset); + workqueue->queue(new Hash_task(of, + src_offset, + size, + dst, + post_hash_tasks_blocker)); + } + } + + // Queue the final task to write the build id and close the output file. + workqueue->queue(new Task_function(new Close_task_runner(this->options_, + layout, + of, + array_of_hashes, + size_of_hashes), + post_hash_tasks_blocker, + "Task_function Close_task_runner")); +} + // Close_task_runner methods. -// Run the task--close the file. +// Finish up the build ID computation, if necessary, and write a binary file, +// if necessary. Then close the output file. void Close_task_runner::run(Workqueue*, const Task*) { - // If we need to compute a checksum for the BUILD if, we do so here. - this->layout_->write_build_id(this->of_); + // At this point the multi-threaded part of the build ID computation, + // if any, is done. See Build_id_task_runner. + this->layout_->write_build_id(this->of_, this->array_of_hashes_, + this->size_of_hashes_); // If we've been asked to create a binary file, we do so here. if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF) @@ -4397,7 +5747,40 @@ Close_task_runner::run(Workqueue*, const Task*) #ifdef HAVE_TARGET_32_LITTLE template Output_section* -Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx, +Layout::init_fixed_output_section<32, false>( + const char* name, + elfcpp::Shdr<32, false>& shdr); +#endif + +#ifdef HAVE_TARGET_32_BIG +template +Output_section* +Layout::init_fixed_output_section<32, true>( + const char* name, + elfcpp::Shdr<32, true>& shdr); +#endif + +#ifdef HAVE_TARGET_64_LITTLE +template +Output_section* +Layout::init_fixed_output_section<64, false>( + const char* name, + elfcpp::Shdr<64, false>& shdr); +#endif + +#ifdef HAVE_TARGET_64_BIG +template +Output_section* +Layout::init_fixed_output_section<64, true>( + const char* name, + elfcpp::Shdr<64, true>& shdr); +#endif + +#ifdef HAVE_TARGET_32_LITTLE +template +Output_section* +Layout::layout<32, false>(Sized_relobj_file<32, false>* object, + unsigned int shndx, const char* name, const elfcpp::Shdr<32, false>& shdr, unsigned int, unsigned int, off_t*); @@ -4406,7 +5789,8 @@ Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx, #ifdef HAVE_TARGET_32_BIG template Output_section* -Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx, +Layout::layout<32, true>(Sized_relobj_file<32, true>* object, + unsigned int shndx, const char* name, const elfcpp::Shdr<32, true>& shdr, unsigned int, unsigned int, off_t*); @@ -4415,7 +5799,8 @@ Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx, #ifdef HAVE_TARGET_64_LITTLE template Output_section* -Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx, +Layout::layout<64, false>(Sized_relobj_file<64, false>* object, + unsigned int shndx, const char* name, const elfcpp::Shdr<64, false>& shdr, unsigned int, unsigned int, off_t*); @@ -4424,7 +5809,8 @@ Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx, #ifdef HAVE_TARGET_64_BIG template Output_section* -Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx, +Layout::layout<64, true>(Sized_relobj_file<64, true>* object, + unsigned int shndx, const char* name, const elfcpp::Shdr<64, true>& shdr, unsigned int, unsigned int, off_t*); @@ -4433,7 +5819,7 @@ Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx, #ifdef HAVE_TARGET_32_LITTLE template Output_section* -Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object, +Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object, unsigned int reloc_shndx, const elfcpp::Shdr<32, false>& shdr, Output_section* data_section, @@ -4443,7 +5829,7 @@ Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object, #ifdef HAVE_TARGET_32_BIG template Output_section* -Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object, +Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object, unsigned int reloc_shndx, const elfcpp::Shdr<32, true>& shdr, Output_section* data_section, @@ -4453,7 +5839,7 @@ Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object, #ifdef HAVE_TARGET_64_LITTLE template Output_section* -Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object, +Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object, unsigned int reloc_shndx, const elfcpp::Shdr<64, false>& shdr, Output_section* data_section, @@ -4463,7 +5849,7 @@ Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object, #ifdef HAVE_TARGET_64_BIG template Output_section* -Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object, +Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object, unsigned int reloc_shndx, const elfcpp::Shdr<64, true>& shdr, Output_section* data_section, @@ -4474,7 +5860,7 @@ Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object, template void Layout::layout_group<32, false>(Symbol_table* symtab, - Sized_relobj<32, false>* object, + Sized_relobj_file<32, false>* object, unsigned int, const char* group_section_name, const char* signature, @@ -4487,7 +5873,7 @@ Layout::layout_group<32, false>(Symbol_table* symtab, template void Layout::layout_group<32, true>(Symbol_table* symtab, - Sized_relobj<32, true>* object, + Sized_relobj_file<32, true>* object, unsigned int, const char* group_section_name, const char* signature, @@ -4500,7 +5886,7 @@ Layout::layout_group<32, true>(Symbol_table* symtab, template void Layout::layout_group<64, false>(Symbol_table* symtab, - Sized_relobj<64, false>* object, + Sized_relobj_file<64, false>* object, unsigned int, const char* group_section_name, const char* signature, @@ -4513,7 +5899,7 @@ Layout::layout_group<64, false>(Symbol_table* symtab, template void Layout::layout_group<64, true>(Symbol_table* symtab, - Sized_relobj<64, true>* object, + Sized_relobj_file<64, true>* object, unsigned int, const char* group_section_name, const char* signature, @@ -4525,7 +5911,7 @@ Layout::layout_group<64, true>(Symbol_table* symtab, #ifdef HAVE_TARGET_32_LITTLE template Output_section* -Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object, +Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object, const unsigned char* symbols, off_t symbols_size, const unsigned char* symbol_names, @@ -4540,9 +5926,9 @@ Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object, #ifdef HAVE_TARGET_32_BIG template Output_section* -Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object, - const unsigned char* symbols, - off_t symbols_size, +Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object, + const unsigned char* symbols, + off_t symbols_size, const unsigned char* symbol_names, off_t symbol_names_size, unsigned int shndx, @@ -4555,7 +5941,7 @@ Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object, #ifdef HAVE_TARGET_64_LITTLE template Output_section* -Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object, +Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object, const unsigned char* symbols, off_t symbols_size, const unsigned char* symbol_names, @@ -4570,9 +5956,9 @@ Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object, #ifdef HAVE_TARGET_64_BIG template Output_section* -Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object, - const unsigned char* symbols, - off_t symbols_size, +Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object, + const unsigned char* symbols, + off_t symbols_size, const unsigned char* symbol_names, off_t symbol_names_size, unsigned int shndx, @@ -4582,4 +5968,52 @@ Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object, off_t* off); #endif +#ifdef HAVE_TARGET_32_LITTLE +template +void +Layout::add_to_gdb_index(bool is_type_unit, + Sized_relobj<32, false>* object, + const unsigned char* symbols, + off_t symbols_size, + unsigned int shndx, + unsigned int reloc_shndx, + unsigned int reloc_type); +#endif + +#ifdef HAVE_TARGET_32_BIG +template +void +Layout::add_to_gdb_index(bool is_type_unit, + Sized_relobj<32, true>* object, + const unsigned char* symbols, + off_t symbols_size, + unsigned int shndx, + unsigned int reloc_shndx, + unsigned int reloc_type); +#endif + +#ifdef HAVE_TARGET_64_LITTLE +template +void +Layout::add_to_gdb_index(bool is_type_unit, + Sized_relobj<64, false>* object, + const unsigned char* symbols, + off_t symbols_size, + unsigned int shndx, + unsigned int reloc_shndx, + unsigned int reloc_type); +#endif + +#ifdef HAVE_TARGET_64_BIG +template +void +Layout::add_to_gdb_index(bool is_type_unit, + Sized_relobj<64, true>* object, + const unsigned char* symbols, + off_t symbols_size, + unsigned int shndx, + unsigned int reloc_shndx, + unsigned int reloc_type); +#endif + } // End namespace gold.