X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gold%2Fmerge.cc;h=8c60f50f3665f54b46c635437174ab7aa4bf4e25;hb=7ef412cf72a197d68e532604cc1fa21351adc858;hp=7f08da6f94c82678fd7013289b4c371eadac0d45;hpb=42e3fe0dd99a68834e4af42f8f1a97c76aa5f098;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/merge.cc b/gold/merge.cc index 7f08da6f94..8c60f50f36 100644 --- a/gold/merge.cc +++ b/gold/merge.cc @@ -1,102 +1,276 @@ // merge.cc -- handle section merging for gold +// Copyright (C) 2006-2020 Free Software Foundation, Inc. +// Written by Ian Lance Taylor . + +// This file is part of gold. + +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 3 of the License, or +// (at your option) any later version. + +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +// MA 02110-1301, USA. + #include "gold.h" #include +#include #include "merge.h" +#include "compressed_output.h" namespace gold { -// Sort the entries in a merge mapping. The key is an input object, a -// section index in that object, and an offset in that section. +// Class Object_merge_map. -bool -Output_merge_base::Merge_key_less::operator()(const Merge_key& mk1, - const Merge_key& mk2) const +// Destructor. + +Object_merge_map::~Object_merge_map() +{ + for (Section_merge_maps::iterator p = this->section_merge_maps_.begin(); + p != this->section_merge_maps_.end(); + ++p) + delete p->second; +} + +// Get the Input_merge_map to use for an input section, or NULL. + +const Object_merge_map::Input_merge_map* +Object_merge_map::get_input_merge_map(unsigned int shndx) const { - // The order of different objects and different sections doesn't - // matter. We want to get consistent results across links so we - // don't use pointer comparison. - if (mk1.object != mk2.object) - return mk1.object->name() < mk2.object->name(); - if (mk1.shndx != mk2.shndx) - return mk1.shndx < mk2.shndx; - return mk1.offset < mk2.offset; + gold_assert(shndx != -1U); + const Section_merge_maps &maps = this->section_merge_maps_; + for (Section_merge_maps::const_iterator i = maps.begin(), e = maps.end(); + i != e; ++i) + { + if (i->first == shndx) + return i->second; + } + return NULL; +} + +// Get or create the Input_merge_map to use for an input section. + +Object_merge_map::Input_merge_map* +Object_merge_map::get_or_make_input_merge_map( + const Output_section_data* output_data, unsigned int shndx) { + Input_merge_map* map = this->get_input_merge_map(shndx); + if (map != NULL) + { + // For a given input section in a given object, every mapping + // must be done with the same Merge_map. + gold_assert(map->output_data == output_data); + return map; + } + + Input_merge_map* new_map = new Input_merge_map; + new_map->output_data = output_data; + Section_merge_maps &maps = this->section_merge_maps_; + maps.push_back(std::make_pair(shndx, new_map)); + return new_map; } -// Add a mapping from an OFFSET in input section SHNDX in object -// OBJECT to an OUTPUT_OFFSET in a merged output section. This -// manages the mapping used to resolve relocations against merged -// sections. +// Add a mapping. void -Output_merge_base::add_mapping(Relobj* object, unsigned int shndx, - off_t offset, off_t output_offset) +Object_merge_map::add_mapping(const Output_section_data* output_data, + unsigned int shndx, + section_offset_type input_offset, + section_size_type length, + section_offset_type output_offset) { - Merge_key mk; - mk.object = object; - mk.shndx = shndx; - mk.offset = offset; - std::pair ins = - this->merge_map_.insert(std::make_pair(mk, output_offset)); - gold_assert(ins.second); + Input_merge_map* map = this->get_or_make_input_merge_map(output_data, shndx); + map->add_mapping(input_offset, length, output_offset); +} + +void +Object_merge_map::Input_merge_map::add_mapping( + section_offset_type input_offset, section_size_type length, + section_offset_type output_offset) { + // Try to merge the new entry in the last one we saw. + if (!this->entries.empty()) + { + Input_merge_entry& entry(this->entries.back()); + + // Use section_size_type to avoid signed/unsigned warnings. + section_size_type input_offset_u = input_offset; + section_size_type output_offset_u = output_offset; + + // If this entry is not in order, we need to sort the vector + // before looking anything up. + if (input_offset_u < entry.input_offset + entry.length) + { + gold_assert(input_offset < entry.input_offset); + gold_assert(input_offset_u + length + <= static_cast(entry.input_offset)); + this->sorted = false; + } + else if (entry.input_offset + entry.length == input_offset_u + && (output_offset == -1 + ? entry.output_offset == -1 + : entry.output_offset + entry.length == output_offset_u)) + { + entry.length += length; + return; + } + } + + Input_merge_entry entry; + entry.input_offset = input_offset; + entry.length = length; + entry.output_offset = output_offset; + this->entries.push_back(entry); } -// Return the output address for an input address. The input address -// is at offset OFFSET in section SHNDX in OBJECT. -// OUTPUT_SECTION_ADDRESS is the address of the output section. If we -// know the address, set *POUTPUT and return true. Otherwise return -// false. +// Get the output offset for an input address. bool -Output_merge_base::do_output_address(const Relobj* object, unsigned int shndx, - off_t offset, - uint64_t output_section_address, - uint64_t* poutput) const +Object_merge_map::get_output_offset(unsigned int shndx, + section_offset_type input_offset, + section_offset_type* output_offset) { - gold_assert(output_section_address == this->address()); - - Merge_key mk; - mk.object = object; - mk.shndx = shndx; - mk.offset = offset; - Merge_map::const_iterator p = this->merge_map_.lower_bound(mk); - - // If MK is not in the map, lower_bound returns the next iterator - // larger than it. - if (p->first.object != object - || p->first.shndx != shndx - || p->first.offset != offset) + Input_merge_map* map = this->get_input_merge_map(shndx); + if (map == NULL) + return false; + + if (!map->sorted) { - if (p == this->merge_map_.begin()) - return false; - --p; + std::sort(map->entries.begin(), map->entries.end(), + Input_merge_compare()); + map->sorted = true; } - if (p->first.object != object || p->first.shndx != shndx) + Input_merge_entry entry; + entry.input_offset = input_offset; + std::vector::const_iterator p = + std::upper_bound(map->entries.begin(), map->entries.end(), + entry, Input_merge_compare()); + if (p == map->entries.begin()) + return false; + --p; + gold_assert(p->input_offset <= input_offset); + + if (input_offset - p->input_offset + >= static_cast(p->length)) return false; - // Any input section is fully mapped: we don't need to know the size - // of the range starting at P->FIRST.OFFSET. - *poutput = output_section_address + p->second + (offset - p->first.offset); + *output_offset = p->output_offset; + if (*output_offset != -1) + *output_offset += (input_offset - p->input_offset); return true; } +// Return whether this is the merge map for section SHNDX. + +const Output_section_data* +Object_merge_map::find_merge_section(unsigned int shndx) const { + const Object_merge_map::Input_merge_map* map = + this->get_input_merge_map(shndx); + if (map == NULL) + return NULL; + return map->output_data; +} + +// Initialize a mapping from input offsets to output addresses. + +template +void +Object_merge_map::initialize_input_to_output_map( + unsigned int shndx, + typename elfcpp::Elf_types::Elf_Addr starting_address, + Unordered_map::Elf_Addr>* initialize_map) +{ + Input_merge_map* map = this->get_input_merge_map(shndx); + gold_assert(map != NULL); + + gold_assert(initialize_map->empty()); + // We know how many entries we are going to add. + // reserve_unordered_map takes an expected count of buckets, not a + // count of elements, so double it to try to reduce collisions. + reserve_unordered_map(initialize_map, map->entries.size() * 2); + + for (Input_merge_map::Entries::const_iterator p = map->entries.begin(); + p != map->entries.end(); + ++p) + { + section_offset_type output_offset = p->output_offset; + if (output_offset != -1) + output_offset += starting_address; + else + { + // If we see a relocation against an address we have chosen + // to discard, we relocate to zero. FIXME: We could also + // issue a warning in this case; that would require + // reporting this somehow and checking it in the routines in + // reloc.h. + output_offset = 0; + } + initialize_map->insert(std::make_pair(p->input_offset, output_offset)); + } +} + +// Class Output_merge_base. + +// Return the output offset for an input offset. The input address is +// at offset OFFSET in section SHNDX in OBJECT. If we know the +// offset, set *POUTPUT and return true. Otherwise return false. + +bool +Output_merge_base::do_output_offset(const Relobj* object, + unsigned int shndx, + section_offset_type offset, + section_offset_type* poutput) const +{ + return object->merge_output_offset(shndx, offset, poutput); +} + +// Record a merged input section for script processing. + +void +Output_merge_base::record_input_section(Relobj* relobj, unsigned int shndx) +{ + gold_assert(this->keeps_input_sections_ && relobj != NULL); + // If this is the first input section, record it. We need do this because + // this->input_sections_ is unordered. + if (this->first_relobj_ == NULL) + { + this->first_relobj_ = relobj; + this->first_shndx_ = shndx; + } + + std::pair result = + this->input_sections_.insert(Section_id(relobj, shndx)); + // We should insert a merge section once only. + gold_assert(result.second); +} + +// Class Output_merge_data. + // Compute the hash code for a fixed-size constant. size_t Output_merge_data::Merge_data_hash::operator()(Merge_data_key k) const { const unsigned char* p = this->pomd_->constant(k); - uint64_t entsize = this->pomd_->entsize(); + section_size_type entsize = + convert_to_section_size_type(this->pomd_->entsize()); // Fowler/Noll/Vo (FNV) hash (type FNV-1a). if (sizeof(size_t) == 8) { size_t result = static_cast(14695981039346656037ULL); - for (uint64_t i = 0; i < entsize; ++i) + for (section_size_type i = 0; i < entsize; ++i) { result &= (size_t) *p++; result *= 1099511628211ULL; @@ -106,7 +280,7 @@ Output_merge_data::Merge_data_hash::operator()(Merge_data_key k) const else { size_t result = 2166136261UL; - for (uint64_t i = 0; i < entsize; ++i) + for (section_size_type i = 0; i < entsize; ++i) { result ^= (size_t) *p++; result *= 16777619UL; @@ -131,20 +305,25 @@ Output_merge_data::Merge_data_eq::operator()(Merge_data_key k1, void Output_merge_data::add_constant(const unsigned char* p) { - uint64_t entsize = this->entsize(); - if (this->len_ + entsize > this->alc_) + section_size_type entsize = convert_to_section_size_type(this->entsize()); + section_size_type addralign = + convert_to_section_size_type(this->addralign()); + section_size_type addsize = std::max(entsize, addralign); + if (this->len_ + addsize > this->alc_) { if (this->alc_ == 0) - this->alc_ = 128 * entsize; + this->alc_ = 128 * addsize; else this->alc_ *= 2; this->p_ = static_cast(realloc(this->p_, this->alc_)); if (this->p_ == NULL) - gold_fatal("out of memory", true); + gold_nomem(); } memcpy(this->p_ + this->len_, p, entsize); - this->len_ += entsize; + if (addsize > entsize) + memset(this->p_ + this->len_ + entsize, 0, addsize - entsize); + this->len_ += addsize; } // Add the input section SHNDX in OBJECT to a merged output section @@ -155,15 +334,27 @@ Output_merge_data::add_constant(const unsigned char* p) bool Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx) { - off_t len; - const unsigned char* p = object->section_contents(shndx, &len); + section_size_type len; + bool is_new; + const unsigned char* p = object->decompressed_section_contents(shndx, &len, + &is_new); - uint64_t entsize = this->entsize(); + section_size_type entsize = convert_to_section_size_type(this->entsize()); if (len % entsize != 0) - return false; + { + if (is_new) + delete[] p; + return false; + } + + this->input_count_ += len / entsize; + + Object_merge_map* merge_map = object->get_or_create_merge_map(); + Object_merge_map::Input_merge_map* input_merge_map = + merge_map->get_or_make_input_merge_map(this, shndx); - for (off_t i = 0; i < len; i += entsize, p += entsize) + for (section_size_type i = 0; i < len; i += entsize, p += entsize) { // Add the constant to the section contents. If we find that it // is already in the hash table, we will remove it again. @@ -181,9 +372,16 @@ Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx) } // Record the offset of this constant in the output section. - this->add_mapping(object, shndx, i, k); + input_merge_map->add_mapping(i, entsize, k); } + // For script processing, we keep the input sections. + if (this->keeps_input_sections()) + record_input_section(object, shndx); + + if (is_new) + delete[] p; + return true; } @@ -191,11 +389,14 @@ Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx) // constants. void -Output_merge_data::do_set_address(uint64_t, off_t) +Output_merge_data::set_final_data_size() { // Release the memory we don't need. this->p_ = static_cast(realloc(this->p_, this->len_)); - gold_assert(this->p_ != NULL); + // An Output_merge_data object may be empty and realloc is allowed + // to return a NULL pointer in this case. An Output_merge_data is empty + // if all its input sections have sizes that are not multiples of entsize. + gold_assert(this->p_ != NULL || this->len_ == 0); this->set_data_size(this->len_); } @@ -208,6 +409,28 @@ Output_merge_data::do_write(Output_file* of) of->write(this->offset(), this->p_, this->len_); } +// Write the data to a buffer. + +void +Output_merge_data::do_write_to_buffer(unsigned char* buffer) +{ + memcpy(buffer, this->p_, this->len_); +} + +// Print merge stats to stderr. + +void +Output_merge_data::do_print_merge_stats(const char* section_name) +{ + fprintf(stderr, + _("%s: %s merged constants size: %lu; input: %zu; output: %zu\n"), + program_name, section_name, + static_cast(this->entsize()), + this->input_count_, this->hashtable_.size()); +} + +// Class Output_merge_string. + // Add an input section to a merged string section. template @@ -215,70 +438,160 @@ bool Output_merge_string::do_add_input_section(Relobj* object, unsigned int shndx) { - off_t len; - const unsigned char* pdata = object->section_contents(shndx, &len); + section_size_type sec_len; + bool is_new; + uint64_t addralign = this->addralign(); + const unsigned char* pdata = object->decompressed_section_contents(shndx, + &sec_len, + &is_new, + &addralign); const Char_type* p = reinterpret_cast(pdata); + const Char_type* pend = p + sec_len / sizeof(Char_type); + const Char_type* pend0 = pend; - if (len % sizeof(Char_type) != 0) + if (sec_len % sizeof(Char_type) != 0) { - fprintf(stderr, - _("%s: %s: mergeable string section length not multiple of " - "character size\n"), - program_name, object->name().c_str()); - gold_exit(false); + object->error(_("mergeable string section length not multiple of " + "character size")); + if (is_new) + delete[] pdata; + return false; } - len /= sizeof(Char_type); - off_t i = 0; - while (i < len) + if (pend[-1] != 0) { - off_t plen = 0; - for (const Char_type* pl = p; *pl != 0; ++pl) - { - ++plen; - if (i + plen >= len) - { - fprintf(stderr, - _("%s: %s: entry in mergeable string section " - "not null terminated\n"), - program_name, object->name().c_str()); - gold_exit(false); - } - } + gold_warning(_("%s: last entry in mergeable string section '%s' " + "not null terminated"), + object->name().c_str(), + object->section_name(shndx).c_str()); + // Find the end of the last NULL-terminated string in the buffer. + while (pend0 > p && pend0[-1] != 0) + --pend0; + } + + Merged_strings_list* merged_strings_list = + new Merged_strings_list(object, shndx); + this->merged_strings_lists_.push_back(merged_strings_list); + Merged_strings& merged_strings = merged_strings_list->merged_strings; + + // Count the number of non-null strings in the section and size the list. + size_t count = 0; + const Char_type* pt = p; + while (pt < pend0) + { + size_t len = string_length(pt); + if (len != 0) + ++count; + pt += len + 1; + } + if (pend0 < pend) + ++count; + merged_strings.reserve(count + 1); + + // The index I is in bytes, not characters. + section_size_type i = 0; - const Char_type* str = this->stringpool_.add(p, NULL); + // We assume here that the beginning of the section is correctly + // aligned, so each string within the section must retain the same + // modulo. + uintptr_t init_align_modulo = (reinterpret_cast(pdata) + & (addralign - 1)); + bool has_misaligned_strings = false; + + while (p < pend) + { + size_t len = p < pend0 ? string_length(p) : pend - p; - this->merged_strings_.push_back(Merged_string(object, shndx, i, str)); + // Within merge input section each string must be aligned. + if (len != 0 + && ((reinterpret_cast(p) & (addralign - 1)) + != init_align_modulo)) + has_misaligned_strings = true; - p += plen + 1; - i += plen + 1; + Stringpool::Key key; + this->stringpool_.add_with_length(p, len, true, &key); + + merged_strings.push_back(Merged_string(i, key)); + p += len + 1; + i += (len + 1) * sizeof(Char_type); } + // Record the last offset in the input section so that we can + // compute the length of the last string. + merged_strings.push_back(Merged_string(i, 0)); + + this->input_count_ += count; + this->input_size_ += i; + + if (has_misaligned_strings) + gold_warning(_("%s: section %s contains incorrectly aligned strings;" + " the alignment of those strings won't be preserved"), + object->name().c_str(), + object->section_name(shndx).c_str()); + + // For script processing, we keep the input sections. + if (this->keeps_input_sections()) + record_input_section(object, shndx); + + if (is_new) + delete[] pdata; + return true; } -// Set the final data size of a merged string section. This is where -// we finalize the mappings from the input sections to the output -// section. +// Finalize the mappings from the input sections to the output +// section, and return the final data size. template -void -Output_merge_string::do_set_address(uint64_t, off_t) +section_size_type +Output_merge_string::finalize_merged_data() { this->stringpool_.set_string_offsets(); - for (typename Merged_strings::const_iterator p = - this->merged_strings_.begin(); - p != this->merged_strings_.end(); - ++p) - this->add_mapping(p->object, p->shndx, p->offset, - this->stringpool_.get_offset(p->string)); + for (typename Merged_strings_lists::const_iterator l = + this->merged_strings_lists_.begin(); + l != this->merged_strings_lists_.end(); + ++l) + { + section_offset_type last_input_offset = 0; + section_offset_type last_output_offset = 0; + Relobj *object = (*l)->object; + Object_merge_map* merge_map = object->get_or_create_merge_map(); + Object_merge_map::Input_merge_map* input_merge_map = + merge_map->get_or_make_input_merge_map(this, (*l)->shndx); + + for (typename Merged_strings::const_iterator p = + (*l)->merged_strings.begin(); + p != (*l)->merged_strings.end(); + ++p) + { + section_size_type length = p->offset - last_input_offset; + if (length > 0) + input_merge_map->add_mapping(last_input_offset, length, + last_output_offset); + last_input_offset = p->offset; + if (p->stringpool_key != 0) + last_output_offset = + this->stringpool_.get_offset_from_key(p->stringpool_key); + } + delete *l; + } + + // Save some memory. This also ensures that this function will work + // if called twice, as may happen if Layout::set_segment_offsets + // finds a better alignment. + this->merged_strings_lists_.clear(); - this->set_data_size(this->stringpool_.get_strtab_size()); + return this->stringpool_.get_strtab_size(); +} - // Save some memory. - this->merged_strings_.clear(); +template +void +Output_merge_string::set_final_data_size() +{ + const off_t final_data_size = this->finalize_merged_data(); + this->set_data_size(final_data_size); } // Write out a merged string section. @@ -290,6 +603,62 @@ Output_merge_string::do_write(Output_file* of) this->stringpool_.write(of, this->offset()); } +// Write a merged string section to a buffer. + +template +void +Output_merge_string::do_write_to_buffer(unsigned char* buffer) +{ + this->stringpool_.write_to_buffer(buffer, this->data_size()); +} + +// Return the name of the types of string to use with +// do_print_merge_stats. + +template +const char* +Output_merge_string::string_name() +{ + gold_unreachable(); + return NULL; +} + +template<> +const char* +Output_merge_string::string_name() +{ + return "strings"; +} + +template<> +const char* +Output_merge_string::string_name() +{ + return "16-bit strings"; +} + +template<> +const char* +Output_merge_string::string_name() +{ + return "32-bit strings"; +} + +// Print merge stats to stderr. + +template +void +Output_merge_string::do_print_merge_stats(const char* section_name) +{ + char buf[200]; + snprintf(buf, sizeof buf, "%s merged %s", section_name, this->string_name()); + fprintf(stderr, _("%s: %s input bytes: %zu\n"), + program_name, buf, this->input_size_); + fprintf(stderr, _("%s: %s input strings: %zu\n"), + program_name, buf, this->input_count_); + this->stringpool_.print_stats(buf); +} + // Instantiate the templates we need. template @@ -301,4 +670,22 @@ class Output_merge_string; template class Output_merge_string; +#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) +template +void +Object_merge_map::initialize_input_to_output_map<32>( + unsigned int shndx, + elfcpp::Elf_types<32>::Elf_Addr starting_address, + Unordered_map::Elf_Addr>*); +#endif + +#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) +template +void +Object_merge_map::initialize_input_to_output_map<64>( + unsigned int shndx, + elfcpp::Elf_types<64>::Elf_Addr starting_address, + Unordered_map::Elf_Addr>*); +#endif + } // End namespace gold.