X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Flayout.cc;h=63b9e0d852f1c4d379abaf0a6d142132f4a355a6;hb=788c8b10e36cc1f18faae28c743d7c3d029608c2;hp=62ccaae2b1ea450b7c3f0cdeabc3e8948d85cd3f;hpb=5cb66f97b7b8dbf0a951e9cf10f6b3ed0f309022;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/layout.cc b/gold/layout.cc index 62ccaae2b1..63b9e0d852 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 Free Software Foundation, Inc. +// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -26,8 +26,10 @@ #include #include #include +#include #include #include +#include #include #include "libiberty.h" #include "md5.h" @@ -45,11 +47,87 @@ #include "compressed_output.h" #include "reduced_debug_output.h" #include "reloc.h" +#include "descriptors.h" +#include "plugin.h" +#include "incremental.h" #include "layout.h" namespace gold { +// Layout::Relaxation_debug_check methods. + +// Check that sections and special data are in reset states. +// We do not save states for Output_sections and special Output_data. +// So we check that they have not assigned any addresses or offsets. +// clean_up_after_relaxation simply resets their addresses and offsets. +void +Layout::Relaxation_debug_check::check_output_data_for_reset_values( + const Layout::Section_list& sections, + const Layout::Data_list& special_outputs) +{ + for(Layout::Section_list::const_iterator p = sections.begin(); + p != sections.end(); + ++p) + gold_assert((*p)->address_and_file_offset_have_reset_values()); + + for(Layout::Data_list::const_iterator p = special_outputs.begin(); + p != special_outputs.end(); + ++p) + gold_assert((*p)->address_and_file_offset_have_reset_values()); +} + +// Save information of SECTIONS for checking later. + +void +Layout::Relaxation_debug_check::read_sections( + const Layout::Section_list& sections) +{ + for(Layout::Section_list::const_iterator p = sections.begin(); + p != sections.end(); + ++p) + { + Output_section* os = *p; + Section_info info; + info.output_section = os; + info.address = os->is_address_valid() ? os->address() : 0; + info.data_size = os->is_data_size_valid() ? os->data_size() : -1; + info.offset = os->is_offset_valid()? os->offset() : -1 ; + this->section_infos_.push_back(info); + } +} + +// Verify SECTIONS using previously recorded information. + +void +Layout::Relaxation_debug_check::verify_sections( + const Layout::Section_list& sections) +{ + size_t i = 0; + for(Layout::Section_list::const_iterator p = sections.begin(); + p != sections.end(); + ++p, ++i) + { + Output_section* os = *p; + uint64_t address = os->is_address_valid() ? os->address() : 0; + off_t data_size = os->is_data_size_valid() ? os->data_size() : -1; + off_t offset = os->is_offset_valid()? os->offset() : -1 ; + + if (i >= this->section_infos_.size()) + { + gold_fatal("Section_info of %s missing.\n", os->name()); + } + const Section_info& info = this->section_infos_[i]; + if (os != info.output_section) + gold_fatal("Section order changed. Expecting %s but see %s\n", + info.output_section->name(), os->name()); + if (address != info.address + || data_size != info.data_size + || offset != info.offset) + gold_fatal("Section %s changed.\n", os->name()); + } +} + // Layout_task_runner methods. // Lay out the sections. This is called after all the input objects @@ -84,8 +162,8 @@ Layout_task_runner::run(Workqueue* workqueue, const Task* task) // Layout methods. -Layout::Layout(const General_options& options, Script_options* script_options) - : options_(options), +Layout::Layout(int number_of_input_files, Script_options* script_options) + : number_of_input_files_(number_of_input_files), script_options_(script_options), namepool_(), sympool_(), @@ -95,16 +173,17 @@ Layout::Layout(const General_options& options, Script_options* script_options) segment_list_(), section_list_(), unattached_section_list_(), - sections_are_attached_(false), special_output_list_(), section_headers_(NULL), tls_segment_(NULL), relro_segment_(NULL), + increase_relro_(0), symtab_section_(NULL), symtab_xindex_(NULL), dynsym_section_(NULL), dynsym_xindex_(NULL), dynamic_section_(NULL), + dynamic_symbol_(NULL), dynamic_data_(NULL), eh_frame_section_(NULL), eh_frame_data_(NULL), @@ -115,11 +194,20 @@ Layout::Layout(const General_options& options, Script_options* script_options) debug_info_(NULL), group_signatures_(), output_file_size_(-1), + have_added_input_section_(false), + sections_are_attached_(false), input_requires_executable_stack_(false), input_with_gnu_stack_note_(false), input_without_gnu_stack_note_(false), has_static_tls_(false), - any_postprocessing_sections_(false) + any_postprocessing_sections_(false), + resized_signatures_(false), + have_stabstr_section_(false), + incremental_inputs_(NULL), + record_output_section_data_from_script_(false), + script_output_section_data_list_(), + segment_states_(NULL), + relaxation_debug_check_(NULL) { // 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. @@ -128,6 +216,14 @@ Layout::Layout(const General_options& options, Script_options* script_options) // We expect two unattached Output_data objects: the file header and // the segment headers. this->special_output_list_.reserve(2); + + // Initialize structure needed for an incremental build. + if (parameters->incremental()) + this->incremental_inputs_ = new Incremental_inputs; + + // The section name pool is worth optimizing in all cases, because + // it is small, but there are often overlaps due to .rel sections. + this->namepool_.set_optimize(); } // Hash a key we use to look up an output section mapping. @@ -138,14 +234,6 @@ Layout::Hash_key::operator()(const Layout::Key& k) const return k.first + k.second.first + k.second.second; } -// Return whether PREFIX is a prefix of STR. - -static inline bool -is_prefix_of(const char* prefix, const char* str) -{ - return strncmp(prefix, str, strlen(prefix)) == 0; -} - // 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. @@ -155,6 +243,7 @@ static const char* gdb_sections[] = // ".debug_aranges", // not used by gdb as of 6.7.1 ".debug_frame", ".debug_info", + ".debug_types", ".debug_line", ".debug_loc", ".debug_macinfo", @@ -168,6 +257,7 @@ static const char* lines_only_debug_sections[] = // ".debug_aranges", // not used by gdb as of 6.7.1 // ".debug_frame", ".debug_info", + // ".debug_types", ".debug_line", // ".debug_loc", // ".debug_macinfo", @@ -198,6 +288,30 @@ is_lines_only_debug_section(const char* str) 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)); +} + // Whether to include this section in the link. template @@ -205,6 +319,9 @@ bool Layout::include_section(Sized_relobj*, const char* name, const elfcpp::Shdr& shdr) { + if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE) + return false; + switch (shdr.get_sh_type()) { case elfcpp::SHT_NULL: @@ -255,6 +372,19 @@ Layout::include_section(Sized_relobj*, const char* name, && !is_gdb_debug_section(name)) 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; + } + // The GNU linker strips .gnu_debuglink sections, so we do too. + // This is a feature used to keep debugging information in + // separate files. + if (strcmp(name, ".gnu_debuglink") == 0) + return false; return true; default: @@ -294,11 +424,16 @@ Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set, // 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. +// 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. Output_section* Layout::get_output_section(const char* name, Stringpool::Key name_key, - elfcpp::Elf_Word type, elfcpp::Elf_Xword flags) + elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, + Output_section_order order, bool is_relro) { elfcpp::Elf_Xword lookup_flags = flags; @@ -347,7 +482,8 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key, } if (os == NULL) - os = this->make_output_section(name, type, flags); + os = this->make_output_section(name, type, flags, order, is_relro); + ins.first->second = os; return os; } @@ -357,13 +493,18 @@ Layout::get_output_section(const char* name, Stringpool::Key name_key, // 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. This will return NULL if the input section should be -// discarded. +// 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. Output_section* Layout::choose_output_section(const Relobj* relobj, const char* name, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, - bool is_input_section) + bool is_input_section, Output_section_order order, + bool is_relro) { // We should not see any input sections after we have attached // sections to segments. @@ -372,11 +513,15 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, // Some flags in the input section should not be automatically // copied to the output section. flags &= ~ (elfcpp::SHF_INFO_LINK - | elfcpp::SHF_LINK_ORDER | 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; + if (this->script_options_->saw_sections_clause()) { // We are using a SECTIONS clause, so the output section is @@ -385,13 +530,32 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, Script_sections* ss = this->script_options_->script_sections(); const char* file_name = relobj == NULL ? NULL : relobj->name().c_str(); Output_section** output_section_slot; - name = ss->output_section_name(file_name, name, &output_section_slot); + Script_sections::Section_type script_section_type; + const char* orig_name = name; + name = ss->output_section_name(file_name, name, &output_section_slot, + &script_section_type); if (name == NULL) { + gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' " + "because it is not allowed by the " + "SECTIONS clause of the linker script"), + orig_name); // The SECTIONS clause says to discard this input section. return NULL; } + // We can only handle script section types ST_NONE and ST_NOLOAD. + switch (script_section_type) + { + case Script_sections::ST_NONE: + break; + case Script_sections::ST_NOLOAD: + flags &= elfcpp::SHF_ALLOC; + break; + default: + gold_unreachable(); + } + // If this is an orphan section--one not mentioned in the linker // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the // default processing below. @@ -399,7 +563,10 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, if (output_section_slot != NULL) { if (*output_section_slot != NULL) - return *output_section_slot; + { + (*output_section_slot)->update_flags_for_input_section(flags); + return *output_section_slot; + } // We don't put sections found in the linker script into // SECTION_NAME_MAP_. That keeps us from getting confused @@ -408,8 +575,29 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, name = this->namepool_.add(name, false, NULL); - Output_section* os = this->make_output_section(name, type, flags); + Output_section* os = this->make_output_section(name, type, flags, + order, is_relro); + os->set_found_in_sections_clause(); + + // Special handling for NOLOAD sections. + if (script_section_type == Script_sections::ST_NOLOAD) + { + os->set_is_noload(); + + // The constructor of Output_section sets addresses of non-ALLOC + // sections to 0 by default. We don't want that for NOLOAD + // sections even if they have no SHF_ALLOC flag. + if ((os->flags() & elfcpp::SHF_ALLOC) == 0 + && os->is_address_valid()) + { + gold_assert(os->address() == 0 + && !os->is_offset_valid() + && !os->is_data_size_valid()); + os->reset_address_and_file_offset(); + } + } + *output_section_slot = os; return os; } @@ -417,19 +605,38 @@ Layout::choose_output_section(const Relobj* relobj, const char* name, // FIXME: Handle SHF_OS_NONCONFORMING somewhere. + size_t len = strlen(name); + char* uncompressed_name = NULL; + + // Compressed debug sections should be mapped to the corresponding + // uncompressed section. + if (is_compressed_debug_section(name)) + { + 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'; + len -= 1; + name = uncompressed_name; + } + // 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 && !parameters->options().relocatable()) + if (is_input_section + && !this->script_options_->saw_sections_clause() + && !parameters->options().relocatable()) name = Layout::output_section_name(name, &len); Stringpool::Key name_key; name = this->namepool_.add_with_length(name, len, true, &name_key); + if (uncompressed_name != NULL) + delete[] uncompressed_name; + // Find or make the output section. The output section is selected // based on the section name, type, and flags. - return this->get_output_section(name, name_key, type, flags); + return this->get_output_section(name, name_key, type, flags, order, is_relro); } // Return the output section to use for input section SHNDX, with name @@ -448,24 +655,49 @@ Layout::layout(Sized_relobj* object, unsigned int shndx, const char* name, const elfcpp::Shdr& shdr, unsigned int reloc_shndx, unsigned int, off_t* off) { + *off = 0; + 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. if (parameters->options().relocatable() && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0) { name = this->namepool_.add(name, true, NULL); - os = this->make_output_section(name, shdr.get_sh_type(), - shdr.get_sh_flags()); + os = this->make_output_section(name, sh_type, shdr.get_sh_flags(), + ORDER_INVALID, false); } else { - os = this->choose_output_section(object, name, shdr.get_sh_type(), - shdr.get_sh_flags(), true); + os = this->choose_output_section(object, name, sh_type, + shdr.get_sh_flags(), true, + ORDER_INVALID, false); if (os == NULL) return NULL; } @@ -483,8 +715,9 @@ Layout::layout(Sized_relobj* object, unsigned int shndx, // FIXME: Handle SHF_LINK_ORDER somewhere. - *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx, + *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx, this->script_options_->saw_sections_clause()); + this->have_added_input_section_ = true; return os; } @@ -513,10 +746,20 @@ Layout::layout_reloc(Sized_relobj* object, gold_unreachable(); name += data_section->name(); - Output_section* os = this->choose_output_section(object, name.c_str(), - sh_type, - shdr.get_sh_flags(), - false); + // In a relocatable link relocs for a grouped section must not be + // combined with other reloc sections. + Output_section* os; + if (!parameters->options().relocatable() + || (data_section->flags() & elfcpp::SHF_GROUP) == 0) + os = this->choose_output_section(object, name.c_str(), sh_type, + shdr.get_sh_flags(), false, + ORDER_INVALID, false); + else + { + const char* n = this->namepool_.add(name.c_str(), true, NULL); + os = this->make_output_section(n, sh_type, shdr.get_sh_flags(), + ORDER_INVALID, false); + } os->set_should_link_to_symtab(); os->set_info_section(data_section); @@ -563,7 +806,8 @@ Layout::layout_group(Symbol_table* symtab, group_section_name = this->namepool_.add(group_section_name, true, NULL); Output_section* os = this->make_output_section(group_section_name, elfcpp::SHT_GROUP, - shdr.get_sh_flags()); + shdr.get_sh_flags(), + ORDER_INVALID, false); // We need to find a symbol with the signature in the symbol table. // If we don't find one now, we need to look again later. @@ -572,6 +816,10 @@ Layout::layout_group(Symbol_table* symtab, os->set_info_symndx(sym); else { + // Reserve some space to minimize reallocations. + if (this->group_signatures_.empty()) + this->group_signatures_.reserve(this->number_of_input_files_ * 16); + // We will wind up using a symbol whose name is the signature. // So just put the signature in the symbol name pool to save it. signature = symtab->canonicalize_name(signature); @@ -609,11 +857,10 @@ Layout::layout_eh_frame(Sized_relobj* object, 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->choose_output_section(object, name, elfcpp::SHT_PROGBITS, - elfcpp::SHF_ALLOC, - false); + elfcpp::SHF_ALLOC, false, + ORDER_EHFRAME, false); if (os == NULL) return NULL; @@ -622,14 +869,13 @@ Layout::layout_eh_frame(Sized_relobj* object, this->eh_frame_section_ = os; this->eh_frame_data_ = new Eh_frame(); - if (this->options_.eh_frame_hdr()) + if (parameters->options().eh_frame_hdr()) { Output_section* hdr_os = - this->choose_output_section(NULL, - ".eh_frame_hdr", + this->choose_output_section(NULL, ".eh_frame_hdr", elfcpp::SHT_PROGBITS, - elfcpp::SHF_ALLOC, - false); + elfcpp::SHF_ALLOC, false, + ORDER_EHFRAME, false); if (hdr_os != NULL) { @@ -644,7 +890,8 @@ Layout::layout_eh_frame(Sized_relobj* object, Output_segment* hdr_oseg; hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME, elfcpp::PF_R); - hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R); + hdr_oseg->add_output_section_to_nonload(hdr_os, + elfcpp::PF_R); } this->eh_frame_data_->set_eh_frame_hdr(hdr_posd); @@ -665,6 +912,10 @@ Layout::layout_eh_frame(Sized_relobj* object, { os->update_flags_for_input_section(shdr.get_sh_flags()); + // A writable .eh_frame section is a RELRO section. + if ((shdr.get_sh_flags() & elfcpp::SHF_WRITE) != 0) + os->set_is_relro(); + // 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 @@ -682,8 +933,9 @@ Layout::layout_eh_frame(Sized_relobj* object, // 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(object, shndx, name, shdr, reloc_shndx, + *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx, saw_sections_clause); + this->have_added_input_section_ = true; } return os; @@ -695,10 +947,11 @@ Layout::layout_eh_frame(Sized_relobj* object, Output_section* Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, - Output_section_data* posd) + Output_section_data* posd, + Output_section_order order, bool is_relro) { Output_section* os = this->choose_output_section(NULL, name, type, flags, - false); + false, order, is_relro); if (os != NULL) os->add_output_section_data(posd); return os; @@ -717,37 +970,24 @@ 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. (To make it easier for them, -// we will rename the ouput section in such cases from .foo to -// .foo.zlib.nnnn, where nnnn is the uncompressed size.) 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. - -static bool -is_compressible_debug_section(const char* secname) -{ - return (strncmp(secname, ".debug", sizeof(".debug") - 1) == 0); -} - // Make a new Output_section, and attach it to segments as -// appropriate. +// appropriate. ORDER is the order in which this section should +// appear in the output segment. IS_RELRO is true if this is a relro +// (read-only after relocations) section. Output_section* Layout::make_output_section(const char* name, elfcpp::Elf_Word type, - elfcpp::Elf_Xword flags) + elfcpp::Elf_Xword flags, + Output_section_order order, bool is_relro) { Output_section* os; if ((flags & elfcpp::SHF_ALLOC) == 0 - && strcmp(this->options_.compress_debug_sections(), "none") != 0 + && strcmp(parameters->options().compress_debug_sections(), "none") != 0 && is_compressible_debug_section(name)) - os = new Output_compressed_section(&this->options_, name, type, flags); - + os = new Output_compressed_section(¶meters->options(), name, type, + flags); else if ((flags & elfcpp::SHF_ALLOC) == 0 - && this->options_.strip_debug_non_line() + && parameters->options().strip_debug_non_line() && strcmp(".debug_abbrev", name) == 0) { os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section( @@ -756,7 +996,7 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, this->debug_info_->set_abbreviations(this->debug_abbrev_); } else if ((flags & elfcpp::SHF_ALLOC) == 0 - && this->options_.strip_debug_non_line() + && parameters->options().strip_debug_non_line() && strcmp(".debug_info", name) == 0) { os = this->debug_info_ = new Output_reduced_debug_info_section( @@ -764,23 +1004,16 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, if (this->debug_abbrev_) this->debug_info_->set_abbreviations(this->debug_abbrev_); } - else - os = new Output_section(name, type, flags); - - this->section_list_.push_back(os); - - // The GNU linker by default sorts some sections by priority, so we - // 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)) - os->set_may_sort_attached_input_sections(); + else + { + // FIXME: const_cast is ugly. + Target* target = const_cast(¶meters->target()); + os = target->make_output_section(name, type, flags); + } // With -z relro, we have to recognize the special sections by name. // There is no other way. + bool is_relro_local = false; if (!this->script_options_->saw_sections_clause() && parameters->options().relro() && type == elfcpp::SHT_PROGBITS @@ -788,14 +1021,52 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, && (flags & elfcpp::SHF_WRITE) != 0) { if (strcmp(name, ".data.rel.ro") == 0) - os->set_is_relro(); + is_relro = true; else if (strcmp(name, ".data.rel.ro.local") == 0) { - os->set_is_relro(); - os->set_is_relro_local(); + is_relro = true; + is_relro_local = 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) + os->set_is_relro(); + + if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0) + order = this->default_section_order(os, is_relro_local); + + os->set_order(order); + + parameters->target().new_output_section(os); + + this->section_list_.push_back(os); + + // The GNU linker by default sorts some sections by priority, so we + // 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)) + os->set_may_sort_attached_input_sections(); + + // Check for .stab*str sections, as .stab* sections need to link to + // them. + if (type == elfcpp::SHT_STRTAB + && !this->have_stabstr_section_ + && strncmp(name, ".stab", 5) == 0 + && strcmp(name + strlen(name) - 3, "str") == 0) + this->have_stabstr_section_ = true; + // 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. @@ -805,6 +1076,74 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, return os; } +// Return the default order in which a section should be placed in an +// output segment. This function captures a lot of the ideas in +// ld/scripttempl/elf.sc in the GNU linker. Note that the order of a +// linker created section is normally set when the section is created; +// this function is used for input sections. + +Output_section_order +Layout::default_section_order(Output_section* os, bool is_relro_local) +{ + gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0); + bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0; + bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0; + bool is_bss = false; + + switch (os->type()) + { + default: + case elfcpp::SHT_PROGBITS: + break; + case elfcpp::SHT_NOBITS: + is_bss = true; + break; + case elfcpp::SHT_RELA: + case elfcpp::SHT_REL: + if (!is_write) + return ORDER_DYNAMIC_RELOCS; + break; + case elfcpp::SHT_HASH: + case elfcpp::SHT_DYNAMIC: + case elfcpp::SHT_SHLIB: + case elfcpp::SHT_DYNSYM: + case elfcpp::SHT_GNU_HASH: + case elfcpp::SHT_GNU_verdef: + case elfcpp::SHT_GNU_verneed: + case elfcpp::SHT_GNU_versym: + if (!is_write) + return ORDER_DYNAMIC_LINKER; + break; + case elfcpp::SHT_NOTE: + return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE; + } + + if ((os->flags() & elfcpp::SHF_TLS) != 0) + return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA; + + if (!is_bss && !is_write) + { + if (is_execinstr) + { + if (strcmp(os->name(), ".init") == 0) + return ORDER_INIT; + else if (strcmp(os->name(), ".fini") == 0) + return ORDER_FINI; + } + return is_execinstr ? ORDER_TEXT : ORDER_READONLY; + } + + if (os->is_relro()) + return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO; + + if (os->is_small_section()) + return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA; + if (os->is_large_section()) + return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA; + + return is_bss ? ORDER_BSS : ORDER_DATA; +} + // Attach output sections to segments. This is called after we have // seen all the input sections. @@ -852,38 +1191,65 @@ Layout::attach_allocated_section_to_segment(Output_section* os) elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags); + // Check for --section-start. + uint64_t addr; + bool is_address_set = parameters->options().section_start(os->name(), &addr); + // In general the only thing we really care about for PT_LOAD - // segments is whether or not they are writable, so that is how we - // search for them. People who need segments sorted on some other - // basis will have to use a linker script. + // segments is whether or not they are writable or executable, + // so that is how we search for them. + // Large data sections also go into their own PT_LOAD segment. + // People who need segments sorted on some other basis will + // have to use a linker script. Segment_list::const_iterator p; for (p = this->segment_list_.begin(); p != this->segment_list_.end(); ++p) { - if ((*p)->type() == elfcpp::PT_LOAD - && ((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W)) - { - // If -Tbss was specified, we need to separate the data - // and BSS segments. - if (this->options_.user_set_Tbss()) - { - if ((os->type() == elfcpp::SHT_NOBITS) - == (*p)->has_any_data_sections()) - continue; - } + 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()) + { + if ((os->type() == elfcpp::SHT_NOBITS) + == (*p)->has_any_data_sections()) + continue; + } + if (os->is_large_data_section() && !(*p)->is_large_data_segment()) + continue; - (*p)->add_output_section(os, seg_flags); - break; - } + 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); + break; + } + + (*p)->add_output_section_to_load(this, os, seg_flags); + break; } if (p == this->segment_list_.end()) { Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD, seg_flags); - oseg->add_output_section(os, 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); } // If we see a loadable SHT_NOTE section, we create a PT_NOTE @@ -899,7 +1265,7 @@ Layout::attach_allocated_section_to_segment(Output_section* os) && (((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W))) { - (*p)->add_output_section(os, seg_flags); + (*p)->add_output_section_to_nonload(os, seg_flags); break; } } @@ -908,7 +1274,7 @@ Layout::attach_allocated_section_to_segment(Output_section* os) { Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE, seg_flags); - oseg->add_output_section(os, seg_flags); + oseg->add_output_section_to_nonload(os, seg_flags); } } @@ -917,9 +1283,8 @@ Layout::attach_allocated_section_to_segment(Output_section* os) if ((flags & elfcpp::SHF_TLS) != 0) { if (this->tls_segment_ == NULL) - this->tls_segment_ = this->make_output_segment(elfcpp::PT_TLS, - seg_flags); - this->tls_segment_->add_output_section(os, seg_flags); + this->make_output_segment(elfcpp::PT_TLS, seg_flags); + this->tls_segment_->add_output_section_to_nonload(os, seg_flags); } // If -z relro is in effect, and we see a relro section, we create a @@ -928,21 +1293,28 @@ Layout::attach_allocated_section_to_segment(Output_section* os) { gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W)); if (this->relro_segment_ == NULL) - this->relro_segment_ = this->make_output_segment(elfcpp::PT_GNU_RELRO, - seg_flags); - this->relro_segment_->add_output_section(os, seg_flags); + this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags); + this->relro_segment_->add_output_section_to_nonload(os, seg_flags); } } // Make an output section for a script. Output_section* -Layout::make_output_section_for_script(const char* name) +Layout::make_output_section_for_script( + const char* name, + Script_sections::Section_type section_type) { name = this->namepool_.add(name, false, NULL); + elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC; + if (section_type == Script_sections::ST_NOLOAD) + sh_flags = 0; Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS, - elfcpp::SHF_ALLOC); + sh_flags, ORDER_INVALID, + false); os->set_found_in_sections_clause(); + if (section_type == Script_sections::ST_NOLOAD) + os->set_is_noload(); return os; } @@ -976,18 +1348,42 @@ 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() + || parameters->options().is_stack_executable()) + gold_warning(_("%s: requires executable stack"), + obj->name().c_str()); + } } } +// Create automatic note sections. + +void +Layout::create_notes() +{ + this->create_gold_note(); + this->create_executable_stack_info(); + this->create_build_id(); +} + // Create the dynamic sections which are needed before we read the // relocs. @@ -1001,12 +1397,14 @@ Layout::create_initial_dynamic_sections(Symbol_table* symtab) elfcpp::SHT_DYNAMIC, (elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE), - false); - this->dynamic_section_->set_is_relro(); + false, ORDER_RELRO, + true); - symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0, - elfcpp::STT_OBJECT, elfcpp::STB_LOCAL, - elfcpp::STV_HIDDEN, 0, false, false); + 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_); @@ -1025,19 +1423,17 @@ Layout::define_section_symbols(Symbol_table* symtab) ++p) { const char* const name = (*p)->name(); - if (name[strspn(name, - ("0123456789" - "ABCDEFGHIJKLMNOPWRSTUVWXYZ" - "abcdefghijklmnopqrstuvwxyz" - "_"))] - == '\0') + if (is_cident(name)) { const std::string name_string(name); - const std::string start_name("__start_" + name_string); - const std::string stop_name("__stop_" + name_string); + const std::string start_name(cident_section_start_prefix + + name_string); + const std::string stop_name(cident_section_stop_prefix + + name_string); symtab->define_in_output_data(start_name.c_str(), NULL, // version + Symbol_table::PREDEFINED, *p, 0, // value 0, // symsize @@ -1050,6 +1446,7 @@ Layout::define_section_symbols(Symbol_table* symtab) symtab->define_in_output_data(stop_name.c_str(), NULL, // version + Symbol_table::PREDEFINED, *p, 0, // value 0, // symsize @@ -1076,45 +1473,385 @@ Layout::define_group_signatures(Symbol_table* symtab) if (sym != NULL) p->section->set_info_symndx(sym); else - { - // Force the name of the group section to the group - // signature, and use the group's section symbol as the - // signature symbol. - if (strcmp(p->section->name(), p->signature) != 0) - { - const char* name = this->namepool_.add(p->signature, - true, NULL); - p->section->set_name(name); - } - p->section->set_needs_symtab_index(); - p->section->set_info_section_symndx(p->section); - } + { + // Force the name of the group section to the group + // signature, and use the group's section symbol as the + // signature symbol. + if (strcmp(p->section->name(), p->signature) != 0) + { + const char* name = this->namepool_.add(p->signature, + true, NULL); + p->section->set_name(name); + } + p->section->set_needs_symtab_index(); + p->section->set_info_section_symndx(p->section); + } + } + + this->group_signatures_.clear(); +} + +// Find the first read-only PT_LOAD segment, creating one if +// necessary. + +Output_segment* +Layout::find_first_load_seg() +{ + Output_segment* best = NULL; + for (Segment_list::const_iterator p = this->segment_list_.begin(); + p != this->segment_list_.end(); + ++p) + { + 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; + } + } + if (best != NULL) + return best; + + gold_assert(!this->script_options_->saw_phdrs_clause()); + + Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD, + elfcpp::PF_R); + return load_seg; +} + +// Save states of all current output segments. Store saved states +// in SEGMENT_STATES. + +void +Layout::save_segments(Segment_states* segment_states) +{ + for (Segment_list::const_iterator p = this->segment_list_.begin(); + p != this->segment_list_.end(); + ++p) + { + Output_segment* segment = *p; + // Shallow copy. + Output_segment* copy = new Output_segment(*segment); + (*segment_states)[segment] = copy; + } +} + +// Restore states of output segments and delete any segment not found in +// SEGMENT_STATES. + +void +Layout::restore_segments(const Segment_states* segment_states) +{ + // Go through the segment list and remove any segment added in the + // relaxation loop. + this->tls_segment_ = NULL; + this->relro_segment_ = NULL; + Segment_list::iterator list_iter = this->segment_list_.begin(); + while (list_iter != this->segment_list_.end()) + { + Output_segment* segment = *list_iter; + Segment_states::const_iterator states_iter = + segment_states->find(segment); + if (states_iter != segment_states->end()) + { + const Output_segment* copy = states_iter->second; + // Shallow copy to restore states. + *segment = *copy; + + // Also fix up TLS and RELRO segment pointers as appropriate. + if (segment->type() == elfcpp::PT_TLS) + this->tls_segment_ = segment; + else if (segment->type() == elfcpp::PT_GNU_RELRO) + this->relro_segment_ = segment; + + ++list_iter; + } + else + { + 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; + } + } +} + +// Clean up after relaxation so that sections can be laid out again. + +void +Layout::clean_up_after_relaxation() +{ + // Restore the segments to point state just prior to the relaxation loop. + Script_sections* script_section = this->script_options_->script_sections(); + script_section->release_segments(); + this->restore_segments(this->segment_states_); + + // Reset section addresses and file offsets + for (Section_list::iterator p = this->section_list_.begin(); + p != this->section_list_.end(); + ++p) + { + (*p)->restore_states(); + + // If an input section changes size because of relaxation, + // we need to adjust the section offsets of all input sections. + // after such a section. + if ((*p)->section_offsets_need_adjustment()) + (*p)->adjust_section_offsets(); + + (*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(); + ++p) + (*p)->reset_address_and_file_offset(); + + // A linker script may have created some output section data objects. + // They are useless now. + for (Output_section_data_list::const_iterator p = + this->script_output_section_data_list_.begin(); + p != this->script_output_section_data_list_.end(); + ++p) + delete *p; + this->script_output_section_data_list_.clear(); +} + +// Prepare for relaxation. + +void +Layout::prepare_for_relaxation() +{ + // Create an relaxation debug check if in debugging mode. + if (is_debugging_enabled(DEBUG_RELAXATION)) + this->relaxation_debug_check_ = new Relaxation_debug_check(); + + // Save segment states. + this->segment_states_ = new Segment_states(); + this->save_segments(this->segment_states_); + + for(Section_list::const_iterator p = this->section_list_.begin(); + p != this->section_list_.end(); + ++p) + (*p)->save_states(); + + if (is_debugging_enabled(DEBUG_RELAXATION)) + this->relaxation_debug_check_->check_output_data_for_reset_values( + this->section_list_, this->special_output_list_); + + // Also enable recording of output section data from scripts. + this->record_output_section_data_from_script_ = true; +} + +// 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. +// +// The number of segments created by a linking script without a PHDRS +// clause may be affected by section sizes and alignments. There is +// a remote chance that relaxation causes different number of PT_LOAD +// segments are created and sections are attached to different segments. +// Therefore, we always throw away all segments created during section +// 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. +// 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. +// SEGMENT_HEADERS points to the output segment header. +// FILE_HEADER points to the output file header. +// PSHNDX is the address to store the output section index. + +off_t inline +Layout::relaxation_loop_body( + int pass, + Target* target, + Symbol_table* symtab, + Output_segment** pload_seg, + Output_segment* phdr_seg, + Output_segment_headers* segment_headers, + Output_file_header* file_header, + unsigned int* pshndx) +{ + // If this is not the first iteration, we need to clean up after + // relaxation so that we can lay out the sections again. + if (pass != 0) + this->clean_up_after_relaxation(); + + // If there is a SECTIONS clause, put all the input sections into + // the required order. + Output_segment* load_seg; + if (this->script_options_->saw_sections_clause()) + load_seg = this->set_section_addresses_from_script(symtab); + else if (parameters->options().relocatable()) + load_seg = NULL; + else + load_seg = this->find_first_load_seg(); + + 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; + + gold_assert(phdr_seg == NULL + || load_seg != NULL + || this->script_options_->saw_sections_clause()); + + // If the address of the load segment we found has been set by + // --section-start rather than by a script, then adjust the VMA and + // LMA downward if possible to include the file and section headers. + uint64_t header_gap = 0; + if (load_seg != NULL + && load_seg->are_addresses_set() + && !this->script_options_->saw_sections_clause() + && !parameters->options().relocatable()) + { + file_header->finalize_data_size(); + segment_headers->finalize_data_size(); + size_t sizeof_headers = (file_header->data_size() + + segment_headers->data_size()); + const uint64_t abi_pagesize = target->abi_pagesize(); + uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers; + hdr_paddr &= ~(abi_pagesize - 1); + uint64_t subtract = load_seg->paddr() - hdr_paddr; + if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract) + load_seg = NULL; + else + { + load_seg->set_addresses(load_seg->vaddr() - subtract, + load_seg->paddr() - subtract); + header_gap = subtract - sizeof_headers; + } + } + + // Lay out the segment headers. + if (!parameters->options().relocatable()) + { + gold_assert(segment_headers != NULL); + if (header_gap != 0 && load_seg != NULL) + { + Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1); + load_seg->add_initial_output_data(z); + } + if (load_seg != NULL) + load_seg->add_initial_output_data(segment_headers); + if (phdr_seg != NULL) + phdr_seg->add_initial_output_data(segment_headers); + } + + // Lay out the file header. + if (load_seg != NULL) + load_seg->add_initial_output_data(file_header); + + if (this->script_options_->saw_phdrs_clause() + && !parameters->options().relocatable()) + { + // Support use of FILEHDRS and PHDRS attachments in a PHDRS + // clause in a linker script. + Script_sections* ss = this->script_options_->script_sections(); + ss->put_headers_in_phdrs(file_header, segment_headers); + } + + // We set the output section indexes in set_segment_offsets and + // set_section_indexes. + *pshndx = 1; + + // Set the file offsets of all the segments, and all the sections + // they contain. + off_t off; + if (!parameters->options().relocatable()) + off = this->set_segment_offsets(target, load_seg, pshndx); + else + off = this->set_relocatable_section_offsets(file_header, pshndx); + + // Verify that the dummy relaxation does not change anything. + if (is_debugging_enabled(DEBUG_RELAXATION)) + { + if (pass == 0) + this->relaxation_debug_check_->read_sections(this->section_list_); + else + this->relaxation_debug_check_->verify_sections(this->section_list_); } - this->group_signatures_.clear(); + *pload_seg = load_seg; + return off; } -// Find the first read-only PT_LOAD segment, creating one if -// necessary. +// Search the list of patterns and find the postion of the given section +// name in the output section. If the section name matches a glob +// pattern and a non-glob name, then the non-glob position takes +// precedence. Return 0 if no match is found. -Output_segment* -Layout::find_first_load_seg() +unsigned int +Layout::find_section_order_index(const std::string& section_name) { - for (Segment_list::const_iterator p = this->segment_list_.begin(); - p != this->segment_list_.end(); - ++p) + Unordered_map::iterator map_it; + map_it = this->input_section_position_.find(section_name); + if (map_it != this->input_section_position_.end()) + return map_it->second; + + // Absolute match failed. Linear search the glob patterns. + std::vector::iterator it; + for (it = this->input_section_glob_.begin(); + it != this->input_section_glob_.end(); + ++it) { - if ((*p)->type() == elfcpp::PT_LOAD - && ((*p)->flags() & elfcpp::PF_R) != 0 - && ((*p)->flags() & elfcpp::PF_W) == 0) - return *p; + 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; + } } + return 0; +} - gold_assert(!this->script_options_->saw_phdrs_clause()); +// Read the sequence of input sections from the file specified with +// --section-ordering-file. - Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD, - elfcpp::PF_R); - return load_seg; +void +Layout::read_layout_from_file() +{ + const char* filename = parameters->options().section_ordering_file(); + std::ifstream in; + std::string line; + + in.open(filename); + if (!in) + gold_fatal(_("unable to open --section-ordering-file file %s: %s"), + filename, strerror(errno)); + + std::getline(in, line); // this chops off the trailing \n, if any + unsigned int position = 1; + + while (in) + { + if (!line.empty() && line[line.length() - 1] == '\r') // Windows + line.resize(line.length() - 1); + // Ignore comments, beginning with '#' + if (line[0] == '#') + { + 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); + position++; + std::getline(in, line); + } } // Finalize the layout. When this is called, we have created all the @@ -1153,13 +1890,11 @@ off_t Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, Target* target, const Task* task) { - target->finalize_sections(this); + target->finalize_sections(this, input_objects, symtab); this->count_local_symbols(task, input_objects); - this->create_gold_note(); - this->create_executable_stack_info(target); - this->create_build_id(); + this->link_stabs_sections(); Output_segment* phdr_seg = NULL; if (!parameters->options().relocatable() && !parameters->doing_static_link()) @@ -1199,67 +1934,51 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, // dynamic string table is complete. this->create_version_sections(&versions, symtab, local_dynamic_count, dynamic_symbols, dynstr); - } - - // If there is a SECTIONS clause, put all the input sections into - // the required order. - Output_segment* load_seg; - if (this->script_options_->saw_sections_clause()) - load_seg = this->set_section_addresses_from_script(symtab); - else if (parameters->options().relocatable()) - load_seg = NULL; - else - load_seg = this->find_first_load_seg(); - - if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF) - load_seg = NULL; - - gold_assert(phdr_seg == NULL || load_seg != NULL); - // Lay out the segment headers. - Output_segment_headers* segment_headers; - if (parameters->options().relocatable()) - segment_headers = NULL; - else - { - segment_headers = new Output_segment_headers(this->segment_list_); - if (load_seg != NULL) - load_seg->add_initial_output_data(segment_headers); - if (phdr_seg != NULL) - phdr_seg->add_initial_output_data(segment_headers); + // Set the size of the _DYNAMIC symbol. We can't do this until + // after we call create_version_sections. + this->set_dynamic_symbol_size(symtab); } + + // Create segment headers. + Output_segment_headers* segment_headers = + (parameters->options().relocatable() + ? NULL + : new Output_segment_headers(this->segment_list_)); // Lay out the file header. - Output_file_header* file_header; - file_header = new Output_file_header(target, symtab, segment_headers, - this->options_.entry()); - if (load_seg != NULL) - load_seg->add_initial_output_data(file_header); + Output_file_header* file_header + = new Output_file_header(target, symtab, segment_headers, + parameters->options().entry()); this->special_output_list_.push_back(file_header); if (segment_headers != NULL) this->special_output_list_.push_back(segment_headers); - if (this->script_options_->saw_phdrs_clause() - && !parameters->options().relocatable()) + // Find approriate places for orphan output sections if we are using + // 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; + int pass = 0; + + // 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 { - // Support use of FILEHDRS and PHDRS attachments in a PHDRS - // clause in a linker script. - Script_sections* ss = this->script_options_->script_sections(); - ss->put_headers_in_phdrs(file_header, segment_headers); + off = this->relaxation_loop_body(pass, target, symtab, &load_seg, + phdr_seg, segment_headers, file_header, + &shndx); + pass++; } - - // We set the output section indexes in set_segment_offsets and - // set_section_indexes. - unsigned int shndx = 1; - - // Set the file offsets of all the segments, and all the sections - // they contain. - off_t off; - if (!parameters->options().relocatable()) - off = this->set_segment_offsets(target, load_seg, &shndx); - else - off = this->set_relocatable_section_offsets(file_header, &shndx); + while (target->may_relax() + && target->relax(pass, input_objects, symtab, this, task)); // 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 @@ -1280,6 +1999,13 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, // be called after the symbol table has been finalized. this->script_options_->finalize_symbols(symtab, this); + // Create the incremental inputs sections. + if (this->incremental_inputs_) + { + this->incremental_inputs_->finalize(); + this->create_incremental_info_sections(symtab); + } + // Create the .shstrtab section. Output_section* shstrtab_section = this->create_shstrtab(); @@ -1297,8 +2023,13 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, // If there are no sections which require postprocessing, we can // handle the section names now, and avoid a resize later. if (!this->any_postprocessing_sections_) - off = this->set_section_offsets(off, + { + off = this->set_section_offsets(off, + POSTPROCESSING_SECTIONS_PASS); + off = + this->set_section_offsets(off, STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS); + } file_header->set_section_info(this->section_headers_, shstrtab_section); @@ -1312,13 +2043,15 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, } // Create a note header following the format defined in the ELF ABI. -// NAME is the name, NOTE_TYPE is the type, DESCSZ is the size of the -// descriptor. ALLOCATE is true if the section should be allocated in -// memory. This returns the new note section. It sets -// *TRAILING_PADDING to the number of trailing zero bytes required. +// NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name +// of the section to create, DESCSZ is the size of the descriptor. +// ALLOCATE is true if the section should be allocated in memory. +// This returns the new note section. It sets *TRAILING_PADDING to +// the number of trailing zero bytes required. Output_section* -Layout::create_note(const char* name, int note_type, size_t descsz, +Layout::create_note(const char* name, int note_type, + const char* section_name, size_t descsz, bool allocate, size_t* trailing_padding) { // Authorities all agree that the values in a .note field should @@ -1385,13 +2118,19 @@ Layout::create_note(const char* name, int note_type, size_t descsz, memcpy(buffer + 3 * (size / 8), name, namesz); - const char* note_name = this->namepool_.add(".note", false, NULL); elfcpp::Elf_Xword flags = 0; + Output_section_order order = ORDER_INVALID; if (allocate) - flags = elfcpp::SHF_ALLOC; - Output_section* os = this->make_output_section(note_name, - elfcpp::SHT_NOTE, - flags); + { + flags = elfcpp::SHF_ALLOC; + order = ORDER_RO_NOTE; + } + Output_section* os = this->choose_output_section(NULL, section_name, + elfcpp::SHT_NOTE, + flags, false, order, false); + if (os == NULL) + return NULL; + Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz, size / 8, "** note header"); @@ -1414,8 +2153,11 @@ Layout::create_gold_note() std::string desc = std::string("gold ") + gold::get_version_string(); size_t trailing_padding; - Output_section *os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION, - desc.size(), false, &trailing_padding); + Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION, + ".note.gnu.gold-version", desc.size(), + false, &trailing_padding); + if (os == NULL) + return; Output_section_data* posd = new Output_data_const(desc, 4); os->add_output_section_data(posd); @@ -1440,11 +2182,11 @@ Layout::create_gold_note() // library, we create a PT_GNU_STACK segment. void -Layout::create_executable_stack_info(const Target* target) +Layout::create_executable_stack_info() { bool is_stack_executable; - if (this->options_.is_execstack_set()) - is_stack_executable = this->options_.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_) return; else @@ -1452,7 +2194,8 @@ Layout::create_executable_stack_info(const Target* target) if (this->input_requires_executable_stack_) is_stack_executable = true; else if (this->input_without_gnu_stack_note_) - is_stack_executable = target->is_default_stack_executable(); + is_stack_executable = + parameters->target().is_default_stack_executable(); else is_stack_executable = false; } @@ -1463,7 +2206,8 @@ Layout::create_executable_stack_info(const Target* target) elfcpp::Elf_Xword flags = 0; if (is_stack_executable) flags |= elfcpp::SHF_EXECINSTR; - this->make_output_section(name, elfcpp::SHT_PROGBITS, flags); + this->make_output_section(name, elfcpp::SHT_PROGBITS, flags, + ORDER_INVALID, false); } else { @@ -1503,14 +2247,14 @@ Layout::create_build_id() char buffer[uuidsz]; memset(buffer, 0, uuidsz); - int descriptor = ::open("/dev/urandom", O_RDONLY); + int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY); if (descriptor < 0) gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"), strerror(errno)); else { ssize_t got = ::read(descriptor, buffer, uuidsz); - ::close(descriptor); + release_descriptor(descriptor, true); if (got < 0) gold_error(_("/dev/urandom: read failed: %s"), strerror(errno)); else if (static_cast(got) != uuidsz) @@ -1547,7 +2291,10 @@ Layout::create_build_id() // Create the note. size_t trailing_padding; Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID, - descsz, true, &trailing_padding); + ".note.gnu.build-id", descsz, true, + &trailing_padding); + if (os == NULL) + return; if (!desc.empty()) { @@ -1570,10 +2317,115 @@ Layout::create_build_id() gold_assert(trailing_padding == 0); this->build_id_note_ = new Output_data_zero_fill(descsz, 4); os->add_output_section_data(this->build_id_note_); - os->set_after_input_sections(); } } +// If we have both .stabXX and .stabXXstr sections, then the sh_link +// field of the former should point to the latter. I'm not sure who +// started this, but the GNU linker does it, and some tools depend +// upon it. + +void +Layout::link_stabs_sections() +{ + if (!this->have_stabstr_section_) + return; + + for (Section_list::iterator p = this->section_list_.begin(); + p != this->section_list_.end(); + ++p) + { + if ((*p)->type() != elfcpp::SHT_STRTAB) + continue; + + const char* name = (*p)->name(); + if (strncmp(name, ".stab", 5) != 0) + continue; + + size_t len = strlen(name); + if (strcmp(name + len - 3, "str") != 0) + continue; + + std::string stab_name(name, len - 3); + Output_section* stab_sec; + stab_sec = this->find_output_section(stab_name.c_str()); + if (stab_sec != NULL) + stab_sec->set_link_section(*p); + } +} + +// Create .gnu_incremental_inputs and related sections needed +// for the next run of incremental linking to check what has changed. + +void +Layout::create_incremental_info_sections(Symbol_table* symtab) +{ + Incremental_inputs* incr = this->incremental_inputs_; + + gold_assert(incr != NULL); + + // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections. + incr->create_data_sections(symtab); + + // Add the .gnu_incremental_inputs section. + const char* incremental_inputs_name = + this->namepool_.add(".gnu_incremental_inputs", false, NULL); + Output_section* incremental_inputs_os = + this->make_output_section(incremental_inputs_name, + elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0, + ORDER_INVALID, false); + incremental_inputs_os->add_output_section_data(incr->inputs_section()); + + // Add the .gnu_incremental_symtab section. + const char* incremental_symtab_name = + this->namepool_.add(".gnu_incremental_symtab", false, NULL); + Output_section* incremental_symtab_os = + this->make_output_section(incremental_symtab_name, + elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0, + ORDER_INVALID, false); + incremental_symtab_os->add_output_section_data(incr->symtab_section()); + incremental_symtab_os->set_entsize(4); + + // Add the .gnu_incremental_relocs section. + const char* incremental_relocs_name = + this->namepool_.add(".gnu_incremental_relocs", false, NULL); + Output_section* incremental_relocs_os = + this->make_output_section(incremental_relocs_name, + elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0, + ORDER_INVALID, false); + incremental_relocs_os->add_output_section_data(incr->relocs_section()); + incremental_relocs_os->set_entsize(incr->relocs_entsize()); + + // Add the .gnu_incremental_got_plt section. + const char* incremental_got_plt_name = + this->namepool_.add(".gnu_incremental_got_plt", false, NULL); + Output_section* incremental_got_plt_os = + this->make_output_section(incremental_got_plt_name, + elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0, + ORDER_INVALID, false); + incremental_got_plt_os->add_output_section_data(incr->got_plt_section()); + + // Add the .gnu_incremental_strtab section. + 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); + Output_data_strtab* strtab_data = + new Output_data_strtab(incr->get_stringpool()); + incremental_strtab_os->add_output_section_data(strtab_data); + + incremental_inputs_os->set_after_input_sections(); + incremental_symtab_os->set_after_input_sections(); + incremental_relocs_os->set_after_input_sections(); + incremental_got_plt_os->set_after_input_sections(); + + incremental_inputs_os->set_link_section(incremental_strtab_os); + incremental_symtab_os->set_link_section(incremental_inputs_os); + incremental_relocs_os->set_link_section(incremental_inputs_os); + incremental_got_plt_os->set_link_section(incremental_inputs_os); +} + // 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. @@ -1659,22 +2511,38 @@ Layout::segment_precedes(const Output_segment* seg1, if (section_count1 > 0 && section_count2 == 0) return false; - uint64_t paddr1 = seg1->first_section_load_address(); - uint64_t paddr2 = seg2->first_section_load_address(); + uint64_t paddr1 = (seg1->are_addresses_set() + ? seg1->paddr() + : seg1->first_section_load_address()); + uint64_t paddr2 = (seg2->are_addresses_set() + ? seg2->paddr() + : seg2->first_section_load_address()); + if (paddr1 != paddr2) return paddr1 < paddr2; } else if (seg2->are_addresses_set()) return false; - // We sort PT_LOAD segments based on the flags. Readonly segments - // come before writable segments. Then writable segments with data - // come before writable segments without data. Then executable - // segments come before non-executable segments. Then the unlikely - // case of a non-readable segment comes before the normal case of a - // readable segment. If there are multiple segments with the same - // type and flags, we require that the address be set, and we sort - // by virtual address and then physical address. + // A segment which holds large data comes after a segment which does + // not hold large data. + if (seg1->is_large_data_segment()) + { + if (!seg2->is_large_data_segment()) + return false; + } + else if (seg2->is_large_data_segment()) + return true; + + // Otherwise, we sort PT_LOAD segments based on the flags. Readonly + // segments come before writable segments. Then writable segments + // with data come before writable segments without data. Then + // executable segments come before non-executable segments. Then + // the unlikely case of a non-readable segment comes before the + // normal case of a readable segment. If there are multiple + // segments with the same type and flags, we require that the + // address be set, and we sort by virtual address and then physical + // address. if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W)) return (flags1 & elfcpp::PF_W) == 0; if ((flags1 & elfcpp::PF_W) != 0 @@ -1690,13 +2558,26 @@ Layout::segment_precedes(const Output_segment* seg1, gold_unreachable(); } +// Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE. + +static off_t +align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize) +{ + uint64_t unsigned_off = off; + uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1)) + | (addr & (abi_pagesize - 1))); + if (aligned_off < unsigned_off) + aligned_off += abi_pagesize; + return aligned_off; +} + // 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. off_t Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, - unsigned int *pshndx) + unsigned int* pshndx) { // Sort them into the final order. std::sort(this->segment_list_.begin(), this->segment_list_.end(), @@ -1705,9 +2586,9 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, // Find the PT_LOAD segments, and set their addresses and offsets // and their section's addresses and offsets. uint64_t addr; - if (this->options_.user_set_Ttext()) - addr = this->options_.Ttext(); - else if (parameters->options().shared()) + if (parameters->options().user_set_Ttext()) + addr = parameters->options().Ttext(); + else if (parameters->options().output_is_position_independent()) addr = 0; else addr = target->default_text_segment_address(); @@ -1728,7 +2609,13 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, } } - bool was_readonly = false; + unsigned int increase_relro = this->increase_relro_; + if (this->script_options_->saw_sections_clause()) + increase_relro = 0; + + const bool check_sections = parameters->options().check_sections(); + Output_segment* last_load_segment = NULL; + for (Segment_list::iterator p = this->segment_list_.begin(); p != this->segment_list_.end(); ++p) @@ -1746,19 +2633,19 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, // the physical address. addr = (*p)->paddr(); } - else if (this->options_.user_set_Tdata() + else if (parameters->options().user_set_Tdata() && ((*p)->flags() & elfcpp::PF_W) != 0 - && (!this->options_.user_set_Tbss() + && (!parameters->options().user_set_Tbss() || (*p)->has_any_data_sections())) { - addr = this->options_.Tdata(); + addr = parameters->options().Tdata(); are_addresses_set = true; } - else if (this->options_.user_set_Tbss() + else if (parameters->options().user_set_Tbss() && ((*p)->flags() & elfcpp::PF_W) != 0 && !(*p)->has_any_data_sections()) { - addr = this->options_.Tbss(); + addr = parameters->options().Tbss(); are_addresses_set = true; } @@ -1767,55 +2654,63 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, uint64_t aligned_addr = 0; uint64_t abi_pagesize = target->abi_pagesize(); + uint64_t common_pagesize = target->common_pagesize(); - // FIXME: This should depend on the -n and -N options. - (*p)->set_minimum_p_align(target->common_pagesize()); + if (!parameters->options().nmagic() + && !parameters->options().omagic()) + (*p)->set_minimum_p_align(common_pagesize); - if (are_addresses_set) - { - // Adjust the file offset to the same address modulo the - // page size. - uint64_t unsigned_off = off; - uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1)) - | (addr & (abi_pagesize - 1))); - if (aligned_off < unsigned_off) - aligned_off += abi_pagesize; - off = aligned_off; - } - else + if (!are_addresses_set) { - // If the last segment was readonly, and this one is - // not, then skip the address forward one page, - // maintaining the same position within the page. This - // lets us store both segments overlapping on a single - // page in the file, but the loader will put them on - // different pages in memory. + // Skip the address forward one page, maintaining the same + // position within the page. This lets us store both segments + // overlapping on a single page in the file, but the loader will + // 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()); aligned_addr = addr; - if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0) - { - if ((addr & (abi_pagesize - 1)) != 0) - addr = addr + abi_pagesize; - } + if ((addr & (abi_pagesize - 1)) != 0) + addr = addr + abi_pagesize; 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) + { + // This is -N or -n with a section script which prevents + // us from using a load segment. We need to ensure that + // the file offset is aligned to the alignment of the + // segment. This is because the linker script + // implicitly assumed a zero offset. If we don't align + // here, then the alignment of the sections in the + // linker script may not match the alignment of the + // sections in the set_section_addresses call below, + // causing an error about dot moving backward. + off = align_address(off, (*p)->maximum_alignment()); + } + unsigned int shndx_hold = *pshndx; + bool has_relro = false; uint64_t new_addr = (*p)->set_section_addresses(this, false, addr, + &increase_relro, + &has_relro, &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 // file space, by instead aligning to the start of a new // page. Here we use the real machine page size rather than - // the ABI mandated page size. + // the ABI mandated page size. If the segment has been + // aligned so that the relro data ends at a page boundary, + // we do not try to realign it. - if (!are_addresses_set && aligned_addr != addr) + if (!are_addresses_set && !has_relro && aligned_addr != addr) { - uint64_t common_pagesize = target->common_pagesize(); uint64_t first_off = (common_pagesize - (aligned_addr & (common_pagesize - 1))); @@ -1830,15 +2725,40 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, addr = align_address(aligned_addr, common_pagesize); addr = align_address(addr, (*p)->maximum_alignment()); off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1)); + off = align_file_offset(off, addr, abi_pagesize); + + increase_relro = this->increase_relro_; + if (this->script_options_->saw_sections_clause()) + increase_relro = 0; + has_relro = false; + new_addr = (*p)->set_section_addresses(this, true, addr, + &increase_relro, + &has_relro, &off, pshndx); } } addr = new_addr; - if (((*p)->flags() & elfcpp::PF_W) == 0) - was_readonly = true; + // Implement --check-sections. We know that the segments + // are sorted by LMA. + if (check_sections && last_load_segment != NULL) + { + gold_assert(last_load_segment->paddr() <= (*p)->paddr()); + if (last_load_segment->paddr() + last_load_segment->memsz() + > (*p)->paddr()) + { + unsigned long long lb1 = last_load_segment->paddr(); + unsigned long long le1 = lb1 + last_load_segment->memsz(); + unsigned long long lb2 = (*p)->paddr(); + unsigned long long le2 = lb2 + (*p)->memsz(); + gold_error(_("load segment overlap [0x%llx -> 0x%llx] and " + "[0x%llx -> 0x%llx]"), + lb1, le1, lb2, le2); + } + } + last_load_segment = *p; } } @@ -1849,7 +2769,9 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, ++p) { if ((*p)->type() != elfcpp::PT_LOAD) - (*p)->set_offset(); + (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO + ? increase_relro + : 0); } // Set the TLS offsets for each section in the PT_TLS segment. @@ -1865,7 +2787,7 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, off_t Layout::set_relocatable_section_offsets(Output_data* file_header, - unsigned int *pshndx) + unsigned int* pshndx) { off_t off = 0; @@ -1974,6 +2896,16 @@ Layout::set_section_indexes(unsigned int shndx) Output_segment* Layout::set_section_addresses_from_script(Symbol_table* symtab) +{ + Script_sections* ss = this->script_options_->script_sections(); + gold_assert(ss->saw_sections_clause()); + return this->script_options_->set_section_addresses(symtab, this); +} + +// Place the orphan sections in the linker script. + +void +Layout::place_orphan_sections_in_script() { Script_sections* ss = this->script_options_->script_sections(); gold_assert(ss->saw_sections_clause()); @@ -1986,8 +2918,6 @@ Layout::set_section_addresses_from_script(Symbol_table* symtab) if (!(*p)->found_in_sections_clause()) ss->place_orphan(*p); } - - return this->script_options_->set_section_addresses(symtab, this); } // Count the local symbols in the regular symbol table and the dynamic @@ -2079,13 +3009,13 @@ Layout::create_symtab_sections(const Input_objects* input_objects, ++p) { unsigned int index = (*p)->finalize_local_symbols(local_symbol_index, - off); + off, symtab); off += (index - local_symbol_index) * symsize; local_symbol_index = index; } unsigned int local_symcount = local_symbol_index; - gold_assert(local_symcount * symsize == off - startoff); + gold_assert(static_cast(local_symcount * symsize) == off - startoff); off_t dynoff; size_t dyn_global_index; @@ -2116,7 +3046,8 @@ Layout::create_symtab_sections(const Input_objects* input_objects, const char* symtab_name = this->namepool_.add(".symtab", false, NULL); Output_section* osymtab = this->make_output_section(symtab_name, elfcpp::SHT_SYMTAB, - 0); + 0, ORDER_INVALID, + false); this->symtab_section_ = osymtab; Output_section_data* pos = new Output_data_fixed_space(off - startoff, @@ -2137,7 +3068,8 @@ Layout::create_symtab_sections(const Input_objects* input_objects, false, NULL); Output_section* osymtab_xindex = this->make_output_section(symtab_xindex_name, - elfcpp::SHT_SYMTAB_SHNDX, 0); + elfcpp::SHT_SYMTAB_SHNDX, 0, + ORDER_INVALID, false); size_t symcount = (off - startoff) / symsize; this->symtab_xindex_ = new Output_symtab_xindex(symcount); @@ -2159,7 +3091,8 @@ Layout::create_symtab_sections(const Input_objects* input_objects, const char* strtab_name = this->namepool_.add(".strtab", false, NULL); Output_section* ostrtab = this->make_output_section(strtab_name, elfcpp::SHT_STRTAB, - 0); + 0, ORDER_INVALID, + false); Output_section_data* pstr = new Output_data_strtab(&this->sympool_); ostrtab->add_output_section_data(pstr); @@ -2186,12 +3119,17 @@ Layout::create_shstrtab() const char* name = this->namepool_.add(".shstrtab", false, NULL); - Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0); + Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0, + ORDER_INVALID, false); - // We can't write out this section until we've set all the section - // names, and we don't set the names of compressed output sections - // until relocations are complete. - os->set_after_input_sections(); + if (strcmp(parameters->options().compress_debug_sections(), "none") != 0) + { + // We can't write out this section until we've set all the + // section names, and we don't set the names of compressed + // output sections until relocations are complete. FIXME: With + // the current names we use, this is unnecessary. + os->set_after_input_sections(); + } Output_section_data* posd = new Output_data_strtab(&this->namepool_); os->add_output_section_data(posd); @@ -2237,7 +3175,7 @@ Layout::allocated_output_section_count() const void Layout::create_dynamic_symtab(const Input_objects* input_objects, Symbol_table* symtab, - Output_section **pdynstr, + Output_section** pdynstr, unsigned int* plocal_dynamic_count, std::vector* pdynamic_symbols, Versions* pversions) @@ -2299,6 +3237,8 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, Output_section* dynsym = this->choose_output_section(NULL, ".dynsym", elfcpp::SHT_DYNSYM, elfcpp::SHF_ALLOC, + false, + ORDER_DYNAMIC_LINKER, false); Output_section_data* odata = new Output_data_fixed_space(index * symsize, @@ -2329,7 +3269,7 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, this->choose_output_section(NULL, ".dynsym_shndx", elfcpp::SHT_SYMTAB_SHNDX, elfcpp::SHF_ALLOC, - false); + false, ORDER_DYNAMIC_LINKER, false); this->dynsym_xindex_ = new Output_symtab_xindex(index); @@ -2352,6 +3292,8 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, Output_section* dynstr = this->choose_output_section(NULL, ".dynstr", elfcpp::SHT_STRTAB, elfcpp::SHF_ALLOC, + false, + ORDER_DYNAMIC_LINKER, false); Output_section_data* strdata = new Output_data_strtab(&this->dynpool_); @@ -2375,10 +3317,10 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount, &phash, &hashlen); - Output_section* hashsec = this->choose_output_section(NULL, ".hash", - elfcpp::SHT_HASH, - elfcpp::SHF_ALLOC, - false); + Output_section* hashsec = + this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH, + elfcpp::SHF_ALLOC, false, + ORDER_DYNAMIC_LINKER, false); Output_section_data* hashdata = new Output_data_const_buffer(phash, hashlen, @@ -2400,10 +3342,10 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount, &phash, &hashlen); - Output_section* hashsec = this->choose_output_section(NULL, ".gnu.hash", - elfcpp::SHT_GNU_HASH, - elfcpp::SHF_ALLOC, - false); + Output_section* hashsec = + this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH, + elfcpp::SHF_ALLOC, false, + ORDER_DYNAMIC_LINKER, false); Output_section_data* hashdata = new Output_data_const_buffer(phash, hashlen, @@ -2412,7 +3354,12 @@ Layout::create_dynamic_symtab(const Input_objects* input_objects, hashsec->add_output_section_data(hashdata); 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_GNU_HASH, hashsec); } @@ -2501,6 +3448,8 @@ Layout::sized_create_version_sections( Output_section* vsec = this->choose_output_section(NULL, ".gnu.version", elfcpp::SHT_GNU_versym, elfcpp::SHF_ALLOC, + false, + ORDER_DYNAMIC_LINKER, false); unsigned char* vbuf; @@ -2526,7 +3475,7 @@ Layout::sized_create_version_sections( vdsec= this->choose_output_section(NULL, ".gnu.version_d", elfcpp::SHT_GNU_verdef, elfcpp::SHF_ALLOC, - false); + false, ORDER_DYNAMIC_LINKER, false); unsigned char* vdbuf; unsigned int vdsize; @@ -2551,7 +3500,7 @@ Layout::sized_create_version_sections( vnsec = this->choose_output_section(NULL, ".gnu.version_r", elfcpp::SHT_GNU_verneed, elfcpp::SHF_ALLOC, - false); + false, ORDER_DYNAMIC_LINKER, false); unsigned char* vnbuf; unsigned int vnsize; @@ -2577,7 +3526,7 @@ Layout::sized_create_version_sections( void Layout::create_interp(const Target* target) { - const char* interp = this->options_.dynamic_linker(); + const char* interp = parameters->options().dynamic_linker(); if (interp == NULL) { interp = target->dynamic_linker(); @@ -2591,6 +3540,7 @@ Layout::create_interp(const Target* target) Output_section* osec = this->choose_output_section(NULL, ".interp", elfcpp::SHT_PROGBITS, elfcpp::SHF_ALLOC, + false, ORDER_INTERP, false); osec->add_output_section_data(odata); @@ -2598,7 +3548,100 @@ Layout::create_interp(const Target* target) { Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP, elfcpp::PF_R); - oseg->add_output_section(osec, elfcpp::PF_R); + oseg->add_output_section_to_nonload(osec, elfcpp::PF_R); + } +} + +// Add dynamic tags for the PLT and the dynamic relocs. This is +// called by the target-specific code. This does nothing if not doing +// a dynamic link. + +// USE_REL is true for REL relocs rather than RELA relocs. + +// If PLT_GOT is not NULL, then DT_PLTGOT points to it. + +// If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL, +// and we also set DT_PLTREL. We use PLT_REL's output section, since +// 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. + +// If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an +// executable. + +void +Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got, + const Output_data* plt_rel, + const Output_data_reloc_generic* dyn_rel, + bool add_debug, bool dynrel_includes_plt) +{ + Output_data_dynamic* odyn = this->dynamic_data_; + if (odyn == NULL) + return; + + if (plt_got != NULL && plt_got->output_section() != NULL) + odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got); + + if (plt_rel != NULL && plt_rel->output_section() != NULL) + { + odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section()); + odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section()); + odyn->add_constant(elfcpp::DT_PLTREL, + use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA); + } + + if (dyn_rel != NULL && dyn_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); + else + odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ, + dyn_rel); + const int size = parameters->target().get_size(); + elfcpp::DT rel_tag; + int rel_size; + if (use_rel) + { + rel_tag = elfcpp::DT_RELENT; + if (size == 32) + rel_size = Reloc_types::reloc_size; + else if (size == 64) + rel_size = Reloc_types::reloc_size; + else + gold_unreachable(); + } + else + { + rel_tag = elfcpp::DT_RELAENT; + if (size == 32) + rel_size = Reloc_types::reloc_size; + else if (size == 64) + rel_size = Reloc_types::reloc_size; + else + gold_unreachable(); + } + odyn->add_constant(rel_tag, rel_size); + + if (parameters->options().combreloc()) + { + size_t c = dyn_rel->relative_reloc_count(); + if (c > 0) + odyn->add_constant((use_rel + ? elfcpp::DT_RELCOUNT + : elfcpp::DT_RELACOUNT), + c); + } + } + + if (add_debug && !parameters->options().shared()) + { + // The value of the DT_DEBUG tag is filled in by the dynamic + // linker at run time, and used by the debugger. + odyn->add_constant(elfcpp::DT_DEBUG, 0); } } @@ -2613,8 +3656,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC, (elfcpp::PF_R | elfcpp::PF_W)); - oseg->add_output_section(this->dynamic_section_, - elfcpp::PF_R | elfcpp::PF_W); + oseg->add_output_section_to_nonload(this->dynamic_section_, + elfcpp::PF_R | elfcpp::PF_W); } Output_data_dynamic* const odyn = this->dynamic_data_; @@ -2623,30 +3666,57 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, p != input_objects->dynobj_end(); ++p) { - // FIXME: Handle --as-needed. + if (!(*p)->is_needed() + && (*p)->input_file()->options().as_needed()) + { + // This dynamic object was linked with --as-needed, but it + // is not needed. + continue; + } + odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname()); } if (parameters->options().shared()) { - const char* soname = this->options_.soname(); + const char* soname = parameters->options().soname(); if (soname != NULL) odyn->add_string(elfcpp::DT_SONAME, soname); } - // FIXME: Support --init and --fini. - Symbol* sym = symtab->lookup("_init"); + Symbol* sym = symtab->lookup(parameters->options().init()); if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj()) odyn->add_symbol(elfcpp::DT_INIT, sym); - sym = symtab->lookup("_fini"); + sym = symtab->lookup(parameters->options().fini()); if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj()) odyn->add_symbol(elfcpp::DT_FINI, sym); - // FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY. - + // Look for .init_array, .preinit_array and .fini_array by checking + // section types. + for(Layout::Section_list::const_iterator p = this->section_list_.begin(); + p != this->section_list_.end(); + ++p) + switch((*p)->type()) + { + case elfcpp::SHT_FINI_ARRAY: + odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *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); + break; + case elfcpp::SHT_PREINIT_ARRAY: + odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *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(this->options_.rpath()); + const General_options::Dir_list& rpath(parameters->options().rpath()); if (!rpath.empty()) { std::string rpath_val; @@ -2685,7 +3755,7 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, ++p) { if (((*p)->flags() & elfcpp::PF_W) == 0 - && (*p)->dynamic_reloc_count() > 0) + && (*p)->has_dynamic_reloc()) { have_textrel = true; break; @@ -2704,7 +3774,7 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, { if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0 - && ((*p)->dynamic_reloc_count() > 0)) + && ((*p)->has_dynamic_reloc())) { have_textrel = true; break; @@ -2720,9 +3790,25 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, // Add a DT_TEXTREL for compatibility with older loaders. odyn->add_constant(elfcpp::DT_TEXTREL, 0); flags |= elfcpp::DF_TEXTREL; + + if (parameters->options().text()) + gold_error(_("read-only segment has dynamic relocations")); + else if (parameters->options().warn_shared_textrel() + && parameters->options().shared()) + gold_warning(_("shared library text segment is not shareable")); } if (parameters->options().shared() && this->has_static_tls()) flags |= elfcpp::DF_STATIC_TLS; + if (parameters->options().origin()) + flags |= elfcpp::DF_ORIGIN; + if (parameters->options().Bsymbolic()) + { + flags |= elfcpp::DF_SYMBOLIC; + // Add DT_SYMBOLIC for compatibility with older loaders. + odyn->add_constant(elfcpp::DT_SYMBOLIC, 0); + } + if (parameters->options().now()) + flags |= elfcpp::DF_BIND_NOW; odyn->add_constant(elfcpp::DT_FLAGS, flags); flags = 0; @@ -2744,61 +3830,88 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, flags &= ~(elfcpp::DF_1_INITFIRST | elfcpp::DF_1_NODELETE | elfcpp::DF_1_NOOPEN); + if (parameters->options().origin()) + flags |= elfcpp::DF_1_ORIGIN; + if (parameters->options().now()) + flags |= elfcpp::DF_1_NOW; if (flags) odyn->add_constant(elfcpp::DT_FLAGS_1, flags); } -// The mapping of .gnu.linkonce section names to real section names. +// Set the size of the _DYNAMIC symbol table to be the size of the +// dynamic data. + +void +Layout::set_dynamic_symbol_size(const Symbol_table* symtab) +{ + Output_data_dynamic* const odyn = this->dynamic_data_; + odyn->finalize_data_size(); + off_t data_size = odyn->data_size(); + const int size = parameters->target().get_size(); + if (size == 32) + symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size); + else if (size == 64) + symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size); + else + gold_unreachable(); +} + +// The mapping of input section name prefixes to output section names. +// In some cases one prefix is itself a prefix of another prefix; in +// such a case the longer prefix must come first. These prefixes are +// based on the GNU linker default ELF linker script. #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 } -const Layout::Linkonce_mapping Layout::linkonce_mapping[] = -{ - MAPPING_INIT("d.rel.ro.local", ".data.rel.ro.local"), // Before "d.rel.ro". - MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Before "d". - MAPPING_INIT("t", ".text"), - MAPPING_INIT("r", ".rodata"), - MAPPING_INIT("d", ".data"), - MAPPING_INIT("b", ".bss"), - MAPPING_INIT("s", ".sdata"), - MAPPING_INIT("sb", ".sbss"), - MAPPING_INIT("s2", ".sdata2"), - MAPPING_INIT("sb2", ".sbss2"), - MAPPING_INIT("wi", ".debug_info"), - MAPPING_INIT("td", ".tdata"), - MAPPING_INIT("tb", ".tbss"), - MAPPING_INIT("lr", ".lrodata"), - MAPPING_INIT("l", ".ldata"), - MAPPING_INIT("lb", ".lbss"), +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.", ".data"), + MAPPING_INIT(".bss.", ".bss"), + MAPPING_INIT(".tdata.", ".tdata"), + MAPPING_INIT(".tbss.", ".tbss"), + MAPPING_INIT(".init_array.", ".init_array"), + MAPPING_INIT(".fini_array.", ".fini_array"), + MAPPING_INIT(".sdata.", ".sdata"), + MAPPING_INIT(".sbss.", ".sbss"), + // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled + // differently depending on whether it is creating a shared library. + MAPPING_INIT(".sdata2.", ".sdata"), + MAPPING_INIT(".sbss2.", ".sbss"), + MAPPING_INIT(".lrodata.", ".lrodata"), + MAPPING_INIT(".ldata.", ".ldata"), + MAPPING_INIT(".lbss.", ".lbss"), + MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"), + MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"), + MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"), + MAPPING_INIT(".gnu.linkonce.t.", ".text"), + MAPPING_INIT(".gnu.linkonce.r.", ".rodata"), + MAPPING_INIT(".gnu.linkonce.d.", ".data"), + MAPPING_INIT(".gnu.linkonce.b.", ".bss"), + MAPPING_INIT(".gnu.linkonce.s.", ".sdata"), + MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"), + MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"), + MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"), + MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"), + MAPPING_INIT(".gnu.linkonce.td.", ".tdata"), + MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"), + MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"), + MAPPING_INIT(".gnu.linkonce.l.", ".ldata"), + MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"), + MAPPING_INIT(".ARM.extab", ".ARM.extab"), + MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"), + MAPPING_INIT(".ARM.exidx", ".ARM.exidx"), + MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"), }; #undef MAPPING_INIT -const int Layout::linkonce_mapping_count = - sizeof(Layout::linkonce_mapping) / sizeof(Layout::linkonce_mapping[0]); - -// Return the name of the output section to use for a .gnu.linkonce -// section. This is based on the default ELF linker script of the old -// GNU linker. For example, we map a name like ".gnu.linkonce.t.foo" -// to ".text". Set *PLEN to the length of the name. *PLEN is -// initialized to the length of NAME. - -const char* -Layout::linkonce_output_name(const char* name, size_t *plen) -{ - const char* s = name + sizeof(".gnu.linkonce") - 1; - if (*s != '.') - return name; - ++s; - const Linkonce_mapping* plm = linkonce_mapping; - for (int i = 0; i < linkonce_mapping_count; ++i, ++plm) - { - if (strncmp(s, plm->from, plm->fromlen) == 0 && s[plm->fromlen] == '.') - { - *plen = plm->tolen; - return plm->to; - } - } - return name; -} +const int Layout::section_name_mapping_count = + (sizeof(Layout::section_name_mapping) + / sizeof(Layout::section_name_mapping[0])); // Choose the output section name to use given an input section name. // Set *PLEN to the length of the name. *PLEN is initialized to the @@ -2807,13 +3920,6 @@ Layout::linkonce_output_name(const char* name, size_t *plen) const char* Layout::output_section_name(const char* name, size_t* plen) { - if (Layout::is_linkonce(name)) - { - // .gnu.linkonce sections are laid out as though they were named - // for the sections are placed into. - return Layout::linkonce_output_name(name, plen); - } - // gcc 4.3 generates the following sorts of section names when it // needs a section name specific to a function: // .text.FN @@ -2840,88 +3946,95 @@ Layout::output_section_name(const char* name, size_t* plen) // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the // GNU linker maps to .rodata. - // The .data.rel.ro sections enable a security feature triggered by - // the -z relro option. Section which need to be relocated at - // program startup time but which may be readonly after startup are - // grouped into .data.rel.ro. They are then put into a PT_GNU_RELRO - // segment. The dynamic linker will make that segment writable, - // perform relocations, and then make it read-only. FIXME: We do - // not yet implement this optimization. + // The .data.rel.ro sections are used with -z relro. The sections + // are recognized by name. We use the same names that the GNU + // linker does for these sections. - // It is hard to handle this in a principled way. - - // These are the rules we follow: - - // If the section name has no initial '.', or no dot other than an - // initial '.', we use the name unchanged (i.e., "mysection" and - // ".text" are unchanged). - - // If the name starts with ".data.rel.ro.local" we use - // ".data.rel.ro.local". - - // If the name starts with ".data.rel.ro" we use ".data.rel.ro". - - // Otherwise, we drop the second '.' and everything that comes after - // it (i.e., ".text.XXX" becomes ".text"). - - const char* s = name; - if (*s != '.') - return name; - ++s; - const char* sdot = strchr(s, '.'); - if (sdot == NULL) - return name; - - const char* const data_rel_ro_local = ".data.rel.ro.local"; - if (strncmp(name, data_rel_ro_local, strlen(data_rel_ro_local)) == 0) - { - *plen = strlen(data_rel_ro_local); - return data_rel_ro_local; - } + // It is hard to handle this in a principled way, so we don't even + // try. We use a table of mappings. If the input section name is + // not found in the table, we simply use it as the output section + // name. - const char* const data_rel_ro = ".data.rel.ro"; - if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0) + const Section_name_mapping* psnm = section_name_mapping; + for (int i = 0; i < section_name_mapping_count; ++i, ++psnm) { - *plen = strlen(data_rel_ro); - return data_rel_ro; + if (strncmp(name, psnm->from, psnm->fromlen) == 0) + { + *plen = psnm->tolen; + return psnm->to; + } } - *plen = sdot - name; return name; } -// Record the signature of a comdat section, and return whether to -// include it in the link. If GROUP is true, this is a regular -// section group. If GROUP is false, this is a group signature -// derived from the name of a linkonce section. We want linkonce -// signatures and group signatures to block each other, but we don't -// want a linkonce signature to block another linkonce signature. +// 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 +// function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and +// IS_GROUP_NAME are recorded for this NAME in the layout object, +// *KEPT_SECTION is set to the internal copy and the function returns +// true. bool -Layout::add_comdat(Relobj* object, unsigned int shndx, - const std::string& signature, bool group) +Layout::find_or_add_kept_section(const std::string& name, + Relobj* object, + unsigned int shndx, + bool is_comdat, + bool is_group_name, + Kept_section** kept_section) { - Kept_section kept(object, shndx, group); - std::pair ins( - this->signatures_.insert(std::make_pair(signature, kept))); + // 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++ + // program, and we resize to get more space to minimize rehashing. + if (this->signatures_.size() > 4 + && !this->resized_signatures_) + { + reserve_unordered_map(&this->signatures_, + this->number_of_input_files_ * 64); + this->resized_signatures_ = true; + } + + Kept_section candidate; + std::pair ins = + this->signatures_.insert(std::make_pair(name, candidate)); + if (kept_section != NULL) + *kept_section = &ins.first->second; if (ins.second) { // This is the first time we've seen this signature. + ins.first->second.set_object(object); + ins.first->second.set_shndx(shndx); + if (is_comdat) + ins.first->second.set_is_comdat(); + if (is_group_name) + ins.first->second.set_is_group_name(); return true; } - if (ins.first->second.group_) + // We have already seen this signature. + + if (ins.first->second.is_group_name()) { // We've already seen a real section group with this signature. + // 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()) + { + ins.first->second.set_object(object); + ins.first->second.set_shndx(shndx); + return true; + } return false; } - else if (group) + else if (is_group_name) { // This is a real section group, and we've already seen a // linkonce section with this signature. Record that we've seen // a section group, and don't include this section group. - ins.first->second.group_ = true; + ins.first->second.set_is_group_name(); return false; } else @@ -2933,20 +4046,6 @@ Layout::add_comdat(Relobj* object, unsigned int shndx, } } -// Find the given comdat signature, and return the object and section -// index of the kept group. -Relobj* -Layout::find_kept_object(const std::string& signature, - unsigned int* pshndx) const -{ - Signatures::const_iterator p = this->signatures_.find(signature); - if (p == this->signatures_.end()) - return NULL; - if (pshndx != NULL) - *pshndx = p->second.shndx_; - return p->second.object_; -} - // Store the allocated sections into the section list. void @@ -2967,6 +4066,12 @@ Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags) gold_assert(!parameters->options().relocatable()); Output_segment* oseg = new Output_segment(type, flags); this->segment_list_.push_back(oseg); + + if (type == elfcpp::PT_TLS) + this->tls_segment_ = oseg; + else if (type == elfcpp::PT_GNU_RELRO) + this->relro_segment_ = oseg; + return oseg; } @@ -3047,7 +4152,7 @@ Layout::write_sections_after_input_sections(Output_file* of) { off_t off = this->output_file_size_; off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS); - + // Now that we've finalized the names, we can finalize the shstrab. off = this->set_section_offsets(off, @@ -3121,7 +4226,7 @@ Layout::write_build_id(Output_file* of) const void Layout::write_binary(Output_file* in) const { - gold_assert(this->options_.oformat_enum() + gold_assert(parameters->options().oformat_enum() == General_options::OBJECT_FORMAT_BINARY); // Get the size of the binary file. @@ -3263,8 +4368,8 @@ Write_symbols_task::locks(Task_locker* tl) void Write_symbols_task::run(Workqueue*) { - this->symtab_->write_globals(this->input_objects_, this->sympool_, - this->dynpool_, this->layout_->symtab_xindex(), + this->symtab_->write_globals(this->sympool_, this->dynpool_, + this->layout_->symtab_xindex(), this->layout_->dynsym_xindex(), this->of_); }