X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gold%2Fstringpool.cc;h=8480c40c307cb83580790a5041be8cffcc08e112;hb=c5edbf3d1c58d59135788f084a3bf681a49e0f9a;hp=4a301fec3a0d7c240842e75b6437cb964b9e0574;hpb=614f30a283ede08a5d2913a0597581edeb7c0905;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/stringpool.cc b/gold/stringpool.cc index 4a301fec3a..8480c40c30 100644 --- a/gold/stringpool.cc +++ b/gold/stringpool.cc @@ -1,5 +1,25 @@ // stringpool.cc -- a string pool for gold +// Copyright (C) 2006-2018 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 @@ -7,56 +27,78 @@ #include #include "output.h" +#include "parameters.h" #include "stringpool.h" namespace gold { template -Stringpool_template::Stringpool_template(bool zero_null) - : string_set_(), strings_(), strtab_size_(0), next_index_(1), - zero_null_(zero_null) +Stringpool_template::Stringpool_template(uint64_t addralign) + : string_set_(), key_to_offset_(), strings_(), strtab_size_(0), + zero_null_(true), optimize_(false), offset_(sizeof(Stringpool_char)), + addralign_(addralign) { + if (parameters->options_valid() + && parameters->options().optimize() >= 2 + && addralign <= sizeof(Stringpool_char)) + this->optimize_ = true; } template -Stringpool_template::~Stringpool_template() +void +Stringpool_template::clear() { for (typename std::list::iterator p = this->strings_.begin(); p != this->strings_.end(); ++p) delete[] reinterpret_cast(*p); + this->strings_.clear(); + this->key_to_offset_.clear(); + this->string_set_.clear(); } -// Return the length of a string of arbitrary character type. - template -size_t -Stringpool_template::string_length(const Stringpool_char* p) +Stringpool_template::~Stringpool_template() { - size_t len = 0; - for (; *p != 0; ++p) - ++len; - return len; + this->clear(); } -// Specialize string_length for char. Maybe we could just use -// std::char_traits<>::length? +// Resize the internal hashtable with the expectation we'll get n new +// elements. Note that the hashtable constructor takes a "number of +// buckets you'd like," rather than "number of elements you'd like," +// but that's the best we can do. -template<> -inline size_t -Stringpool_template::string_length(const char* p) +template +void +Stringpool_template::reserve(unsigned int n) { - return strlen(p); + this->key_to_offset_.reserve(n); + +#if defined(HAVE_UNORDERED_MAP) + this->string_set_.rehash(this->string_set_.size() + n); + return; +#elif defined(HAVE_TR1_UNORDERED_MAP) + // rehash() implementation is broken in gcc 4.0.3's stl + //this->string_set_.rehash(this->string_set_.size() + n); + //return; +#elif defined(HAVE_EXT_HASH_MAP) + this->string_set_.resize(this->string_set_.size() + n); + return; +#endif + + // This is the generic "reserve" code, if no #ifdef above triggers. + String_set_type new_string_set(this->string_set_.size() + n); + new_string_set.insert(this->string_set_.begin(), this->string_set_.end()); + this->string_set_.swap(new_string_set); } -// Equality comparison function. +// Compare two strings of arbitrary character type for equality. template bool -Stringpool_template::Stringpool_eq::operator()( - const Stringpool_char* s1, - const Stringpool_char* s2) const +Stringpool_template::string_equal(const Stringpool_char* s1, + const Stringpool_char* s2) { while (*s1 != 0) if (*s1++ != *s2++) @@ -64,63 +106,49 @@ Stringpool_template::Stringpool_eq::operator()( return *s2 == 0; } -// Specialize equality comparison for char. +// Specialize string_equal for char. template<> -bool -Stringpool_template::Stringpool_eq::operator()(const char* s1, - const char* s2) const +inline bool +Stringpool_template::string_equal(const char* s1, const char* s2) { return strcmp(s1, s2) == 0; } -// Hash function. +// Equality comparison function for the hash table. + +template +inline bool +Stringpool_template::Stringpool_eq::operator()( + const Hashkey& h1, + const Hashkey& h2) const +{ + return (h1.hash_code == h2.hash_code + && h1.length == h2.length + && (h1.string == h2.string + || memcmp(h1.string, h2.string, + h1.length * sizeof(Stringpool_char)) == 0)); +} + +// Hash function. The length is in characters, not bytes. template size_t -Stringpool_template::Stringpool_hash::operator()( - const Stringpool_char* s) const +Stringpool_template::string_hash(const Stringpool_char* s, + size_t length) { - // Fowler/Noll/Vo (FNV) hash (type FNV-1a). - if (sizeof(size_t) == 8) - { - size_t result = static_cast(14695981039346656037ULL); - while (*s != 0) - { - const char* p = reinterpret_cast(s); - for (size_t i = 0; i < sizeof(Stringpool_char); ++i) - { - result &= (size_t) *p++; - result *= 1099511628211ULL; - } - ++s; - } - return result; - } - else - { - size_t result = 2166136261UL; - while (*s != 0) - { - const char* p = reinterpret_cast(s); - for (size_t i = 0; i < sizeof(Stringpool_char); ++i) - { - result ^= (size_t) *p++; - result *= 16777619UL; - } - ++s; - } - return result; - } + return gold::string_hash(s, length); } -// Add a string to the list of canonical strings. Return a pointer to -// the canonical string. If PKEY is not NULL, set *PKEY to the key. +// Add the string S to the list of canonical strings. Return a +// pointer to the canonical string. If PKEY is not NULL, set *PKEY to +// the key. LENGTH is the length of S in characters. Note that S may +// not be NUL terminated. template const Stringpool_char* Stringpool_template::add_string(const Stringpool_char* s, - Key* pkey) + size_t len) { // We are in trouble if we've already computed the string offsets. gold_assert(this->strtab_size_ == 0); @@ -132,7 +160,9 @@ Stringpool_template::add_string(const Stringpool_char* s, const size_t key_mult = 1024; gold_assert(key_mult >= buffer_size); - size_t len = (string_length(s) + 1) * sizeof(Stringpool_char); + // Convert len to the number of bytes we need to allocate, including + // the null character. + len = (len + 1) * sizeof(Stringpool_char); size_t alc; bool front = true; @@ -145,16 +175,15 @@ Stringpool_template::add_string(const Stringpool_char* s, alc = sizeof(Stringdata) + buffer_size; else { - Stringdata *psd = this->strings_.front(); + Stringdata* psd = this->strings_.front(); if (len > psd->alc - psd->len) alc = sizeof(Stringdata) + buffer_size; else { char* ret = psd->data + psd->len; - memcpy(ret, s, len); - - if (pkey != NULL) - *pkey = psd->index * key_mult + psd->len; + memcpy(ret, s, len - sizeof(Stringpool_char)); + memset(ret + len - sizeof(Stringpool_char), 0, + sizeof(Stringpool_char)); psd->len += len; @@ -162,15 +191,12 @@ Stringpool_template::add_string(const Stringpool_char* s, } } - Stringdata *psd = reinterpret_cast(new char[alc]); + Stringdata* psd = reinterpret_cast(new char[alc]); psd->alc = alc - sizeof(Stringdata); - memcpy(psd->data, s, len); + memcpy(psd->data, s, len - sizeof(Stringpool_char)); + memset(psd->data + len - sizeof(Stringpool_char), 0, + sizeof(Stringpool_char)); psd->len = len; - psd->index = this->next_index_; - ++this->next_index_; - - if (pkey != NULL) - *pkey = psd->index * key_mult; if (front) this->strings_.push_front(psd); @@ -184,49 +210,98 @@ Stringpool_template::add_string(const Stringpool_char* s, template const Stringpool_char* -Stringpool_template::add(const Stringpool_char* s, Key* pkey) +Stringpool_template::add(const Stringpool_char* s, bool copy, + Key* pkey) +{ + return this->add_with_length(s, string_length(s), copy, pkey); +} + +// Add a new key offset entry. + +template +void +Stringpool_template::new_key_offset(size_t length) { - // FIXME: This will look up the entry twice in the hash table. The - // problem is that we can't insert S before we canonicalize it. I - // don't think there is a way to handle this correctly with - // unordered_map, so this should be replaced with custom code to do - // what we need, which is to return the empty slot. + section_offset_type offset; + if (this->zero_null_ && length == 0) + offset = 0; + else + { + offset = this->offset_; + // Align strings. + offset = align_address(offset, this->addralign_); + this->offset_ = offset + (length + 1) * sizeof(Stringpool_char); + } + this->key_to_offset_.push_back(offset); +} + +template +const Stringpool_char* +Stringpool_template::add_with_length(const Stringpool_char* s, + size_t length, + bool copy, + Key* pkey) +{ + typedef std::pair Insert_type; + + // We add 1 so that 0 is always invalid. + const Key k = this->key_to_offset_.size() + 1; + + if (!copy) + { + // When we don't need to copy the string, we can call insert + // directly. + + std::pair element(Hashkey(s, length), k); + + Insert_type ins = this->string_set_.insert(element); + + typename String_set_type::const_iterator p = ins.first; + + if (ins.second) + { + // We just added the string. The key value has now been + // used. + this->new_key_offset(length); + } + else + { + gold_assert(k != p->second); + } + + if (pkey != NULL) + *pkey = p->second; + return p->first.string; + } + + // When we have to copy the string, we look it up twice in the hash + // table. The problem is that we can't insert S before we + // canonicalize it by copying it into the canonical list. The hash + // code will only be computed once. - typename String_set_type::const_iterator p = this->string_set_.find(s); + Hashkey hk(s, length); + typename String_set_type::const_iterator p = this->string_set_.find(hk); if (p != this->string_set_.end()) { if (pkey != NULL) - *pkey = p->second.first; - return p->first; + *pkey = p->second; + return p->first.string; } - Key k; - const Stringpool_char* ret = this->add_string(s, &k); + this->new_key_offset(length); + + hk.string = this->add_string(s, length); + // The contents of the string stay the same, so we don't need to + // adjust hk.hash_code or hk.length. + + std::pair element(hk, k); - const off_t ozero = 0; - std::pair element(ret, - std::make_pair(k, ozero)); - std::pair ins = - this->string_set_.insert(element); + Insert_type ins = this->string_set_.insert(element); gold_assert(ins.second); if (pkey != NULL) *pkey = k; - - return ret; -} - -// Add a prefix of a string to a string pool. - -template -const Stringpool_char* -Stringpool_template::add(const Stringpool_char* s, size_t len, - Key* pkey) -{ - // FIXME: This implementation should be rewritten when we rewrite - // the hash table to avoid copying. - std::basic_string st(s, len); - return this->add(st, pkey); + return hk.string; } template @@ -234,14 +309,15 @@ const Stringpool_char* Stringpool_template::find(const Stringpool_char* s, Key* pkey) const { - typename String_set_type::const_iterator p = this->string_set_.find(s); + Hashkey hk(s); + typename String_set_type::const_iterator p = this->string_set_.find(hk); if (p == this->string_set_.end()) return NULL; if (pkey != NULL) - *pkey = p->second.first; + *pkey = p->second; - return p->first; + return p->first.string; } // Comparison routine used when sorting into an ELF strtab. We want @@ -261,10 +337,12 @@ Stringpool_template::Stringpool_sort_comparison::operator()( const Stringpool_sort_info& sort_info1, const Stringpool_sort_info& sort_info2) const { - const Stringpool_char* s1 = sort_info1.it->first; - const Stringpool_char* s2 = sort_info2.it->first; - const size_t len1 = sort_info1.string_length; - const size_t len2 = sort_info2.string_length; + const Hashkey& h1(sort_info1->first); + const Hashkey& h2(sort_info2->first); + const Stringpool_char* s1 = h1.string; + const Stringpool_char* s2 = h2.string; + const size_t len1 = h1.length; + const size_t len2 = h2.length; const size_t minlen = len1 < len2 ? len1 : len2; const Stringpool_char* p1 = s1 + len1 - 1; const Stringpool_char* p2 = s2 + len2 - 1; @@ -303,42 +381,62 @@ Stringpool_template::set_string_offsets() return; } - size_t count = this->string_set_.size(); - - std::vector v; - v.reserve(count); - - for (typename String_set_type::iterator p = this->string_set_.begin(); - p != this->string_set_.end(); - ++p) - v.push_back(Stringpool_sort_info(p, string_length(p->first))); - - std::sort(v.begin(), v.end(), Stringpool_sort_comparison()); - const size_t charsize = sizeof(Stringpool_char); // Offset 0 may be reserved for the empty string. - off_t offset = this->zero_null_ ? charsize : 0; - - for (typename std::vector::iterator last = v.end(), - curr = v.begin(); - curr != v.end(); - last = curr++) + section_offset_type offset = this->zero_null_ ? charsize : 0; + + // Sorting to find suffixes can take over 25% of the total CPU time + // used by the linker. Since it's merely an optimization to reduce + // the strtab size, and gives a relatively small benefit (it's + // typically rare for a symbol to be a suffix of another), we only + // take the time to sort when the user asks for heavy optimization. + if (!this->optimize_) { - if (this->zero_null_ && curr->it->first[0] == 0) - curr->it->second.second = 0; - else if (last != v.end() - && is_suffix(curr->it->first, curr->string_length, - last->it->first, last->string_length)) - curr->it->second.second = (last->it->second.second - + ((last->string_length - - curr->string_length) - * charsize)); - else - { - curr->it->second.second = offset; - offset += (curr->string_length + 1) * charsize; - } + // If we are not optimizing, the offsets are already assigned. + offset = this->offset_; + } + else + { + size_t count = this->string_set_.size(); + + std::vector v; + v.reserve(count); + + for (typename String_set_type::iterator p = this->string_set_.begin(); + p != this->string_set_.end(); + ++p) + v.push_back(Stringpool_sort_info(p)); + + std::sort(v.begin(), v.end(), Stringpool_sort_comparison()); + + section_offset_type last_offset = -1; + for (typename std::vector::iterator last = v.end(), + curr = v.begin(); + curr != v.end(); + last = curr++) + { + section_offset_type this_offset; + if (this->zero_null_ && (*curr)->first.string[0] == 0) + this_offset = 0; + else if (last != v.end() + && ((((*curr)->first.length - (*last)->first.length) + % this->addralign_) == 0) + && is_suffix((*curr)->first.string, + (*curr)->first.length, + (*last)->first.string, + (*last)->first.length)) + this_offset = (last_offset + + (((*last)->first.length - (*curr)->first.length) + * charsize)); + else + { + this_offset = align_address(offset, this->addralign_); + offset = this_offset + ((*curr)->first.length + 1) * charsize; + } + this->key_to_offset_[(*curr)->second - 1] = this_offset; + last_offset = this_offset; + } } this->strtab_size_ = offset; @@ -348,34 +446,79 @@ Stringpool_template::set_string_offsets() // exist. template -off_t +section_offset_type Stringpool_template::get_offset(const Stringpool_char* s) const +{ + return this->get_offset_with_length(s, string_length(s)); +} + +template +section_offset_type +Stringpool_template::get_offset_with_length( + const Stringpool_char* s, + size_t length) const { gold_assert(this->strtab_size_ != 0); - typename String_set_type::const_iterator p = this->string_set_.find(s); + Hashkey hk(s, length); + typename String_set_type::const_iterator p = this->string_set_.find(hk); if (p != this->string_set_.end()) - return p->second.second; + return this->key_to_offset_[p->second - 1]; gold_unreachable(); } -// Write the ELF strtab into the output file at the specified offset. +// Write the ELF strtab into the buffer. template void -Stringpool_template::write(Output_file* of, off_t offset) +Stringpool_template::write_to_buffer( + unsigned char* buffer, + section_size_type bufsize) { gold_assert(this->strtab_size_ != 0); - unsigned char* viewu = of->get_output_view(offset, this->strtab_size_); - char* view = reinterpret_cast(viewu); + gold_assert(bufsize >= this->strtab_size_); if (this->zero_null_) - view[0] = '\0'; + buffer[0] = '\0'; for (typename String_set_type::const_iterator p = this->string_set_.begin(); p != this->string_set_.end(); ++p) - memcpy(view + p->second.second, p->first, - (string_length(p->first) + 1) * sizeof(Stringpool_char)); - of->write_output_view(offset, this->strtab_size_, viewu); + { + const int len = (p->first.length + 1) * sizeof(Stringpool_char); + const section_offset_type offset = this->key_to_offset_[p->second - 1]; + gold_assert(static_cast(offset) + len + <= this->strtab_size_); + memcpy(buffer + offset, p->first.string, len); + } +} + +// Write the ELF strtab into the output file at the specified offset. + +template +void +Stringpool_template::write(Output_file* of, off_t offset) +{ + gold_assert(this->strtab_size_ != 0); + unsigned char* view = of->get_output_view(offset, this->strtab_size_); + this->write_to_buffer(view, this->strtab_size_); + of->write_output_view(offset, this->strtab_size_, view); +} + +// Print statistical information to stderr. This is used for --stats. + +template +void +Stringpool_template::print_stats(const char* name) const +{ +#if defined(HAVE_UNORDERED_MAP) || defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP) + fprintf(stderr, _("%s: %s entries: %zu; buckets: %zu\n"), + program_name, name, this->string_set_.size(), + this->string_set_.bucket_count()); +#else + fprintf(stderr, _("%s: %s entries: %zu\n"), + program_name, name, this->table_.size()); +#endif + fprintf(stderr, _("%s: %s Stringdata structures: %zu\n"), + program_name, name, this->strings_.size()); } // Instantiate the templates we need.