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Diffstat (limited to 'binutils-2.25/gold/stringpool.cc')
| -rw-r--r-- | binutils-2.25/gold/stringpool.cc | 529 |
1 files changed, 529 insertions, 0 deletions
diff --git a/binutils-2.25/gold/stringpool.cc b/binutils-2.25/gold/stringpool.cc new file mode 100644 index 00000000..665fcc8c --- /dev/null +++ b/binutils-2.25/gold/stringpool.cc @@ -0,0 +1,529 @@ +// stringpool.cc -- a string pool for gold + +// Copyright 2006, 2007, 2008 Free Software Foundation, Inc. +// Written by Ian Lance Taylor <iant@google.com>. + +// This file is part of gold. + +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 3 of the License, or +// (at your option) any later version. + +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +// MA 02110-1301, USA. + +#include "gold.h" + +#include <cstring> +#include <algorithm> +#include <vector> + +#include "output.h" +#include "parameters.h" +#include "stringpool.h" + +namespace gold +{ + +template<typename Stringpool_char> +Stringpool_template<Stringpool_char>::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) + this->optimize_ = true; +} + +template<typename Stringpool_char> +void +Stringpool_template<Stringpool_char>::clear() +{ + for (typename std::list<Stringdata*>::iterator p = this->strings_.begin(); + p != this->strings_.end(); + ++p) + delete[] reinterpret_cast<char*>(*p); + this->strings_.clear(); + this->key_to_offset_.clear(); + this->string_set_.clear(); +} + +template<typename Stringpool_char> +Stringpool_template<Stringpool_char>::~Stringpool_template() +{ + this->clear(); +} + +// 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<typename Stringpool_char> +void +Stringpool_template<Stringpool_char>::reserve(unsigned int n) +{ + this->key_to_offset_.reserve(n); + +#if 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); +} + +// Compare two strings of arbitrary character type for equality. + +template<typename Stringpool_char> +bool +Stringpool_template<Stringpool_char>::string_equal(const Stringpool_char* s1, + const Stringpool_char* s2) +{ + while (*s1 != 0) + if (*s1++ != *s2++) + return false; + return *s2 == 0; +} + +// Specialize string_equal for char. + +template<> +inline bool +Stringpool_template<char>::string_equal(const char* s1, const char* s2) +{ + return strcmp(s1, s2) == 0; +} + +// Equality comparison function for the hash table. + +template<typename Stringpool_char> +inline bool +Stringpool_template<Stringpool_char>::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<typename Stringpool_char> +size_t +Stringpool_template<Stringpool_char>::string_hash(const Stringpool_char* s, + size_t length) +{ + return gold::string_hash<Stringpool_char>(s, length); +} + +// 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<typename Stringpool_char> +const Stringpool_char* +Stringpool_template<Stringpool_char>::add_string(const Stringpool_char* s, + size_t len) +{ + // We are in trouble if we've already computed the string offsets. + gold_assert(this->strtab_size_ == 0); + + // The size we allocate for a new Stringdata. + const size_t buffer_size = 1000; + // The amount we multiply the Stringdata index when calculating the + // key. + const size_t key_mult = 1024; + gold_assert(key_mult >= buffer_size); + + // 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; + if (len > buffer_size) + { + alc = sizeof(Stringdata) + len; + front = false; + } + else if (this->strings_.empty()) + alc = sizeof(Stringdata) + buffer_size; + else + { + 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 - sizeof(Stringpool_char)); + memset(ret + len - sizeof(Stringpool_char), 0, + sizeof(Stringpool_char)); + + psd->len += len; + + return reinterpret_cast<const Stringpool_char*>(ret); + } + } + + Stringdata* psd = reinterpret_cast<Stringdata*>(new char[alc]); + psd->alc = alc - sizeof(Stringdata); + memcpy(psd->data, s, len - sizeof(Stringpool_char)); + memset(psd->data + len - sizeof(Stringpool_char), 0, + sizeof(Stringpool_char)); + psd->len = len; + + if (front) + this->strings_.push_front(psd); + else + this->strings_.push_back(psd); + + return reinterpret_cast<const Stringpool_char*>(psd->data); +} + +// Add a string to a string pool. + +template<typename Stringpool_char> +const Stringpool_char* +Stringpool_template<Stringpool_char>::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<typename Stringpool_char> +void +Stringpool_template<Stringpool_char>::new_key_offset(size_t length) +{ + section_offset_type offset; + if (this->zero_null_ && length == 0) + offset = 0; + else + { + offset = this->offset_; + // Align non-zero length strings. + if (length != 0) + offset = align_address(offset, this->addralign_); + this->offset_ = offset + (length + 1) * sizeof(Stringpool_char); + } + this->key_to_offset_.push_back(offset); +} + +template<typename Stringpool_char> +const Stringpool_char* +Stringpool_template<Stringpool_char>::add_with_length(const Stringpool_char* s, + size_t length, + bool copy, + Key* pkey) +{ + typedef std::pair<typename String_set_type::iterator, bool> 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<Hashkey, Hashval> 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. + + 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; + return p->first.string; + } + + 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<Hashkey, Hashval> element(hk, k); + + Insert_type ins = this->string_set_.insert(element); + gold_assert(ins.second); + + if (pkey != NULL) + *pkey = k; + return hk.string; +} + +template<typename Stringpool_char> +const Stringpool_char* +Stringpool_template<Stringpool_char>::find(const Stringpool_char* s, + Key* pkey) const +{ + 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; + + return p->first.string; +} + +// Comparison routine used when sorting into an ELF strtab. We want +// to sort this so that when one string is a suffix of another, we +// always see the shorter string immediately after the longer string. +// For example, we want to see these strings in this order: +// abcd +// cd +// d +// When strings are not suffixes, we don't care what order they are +// in, but we need to ensure that suffixes wind up next to each other. +// So we do a reversed lexicographic sort on the reversed string. + +template<typename Stringpool_char> +bool +Stringpool_template<Stringpool_char>::Stringpool_sort_comparison::operator()( + const Stringpool_sort_info& sort_info1, + const Stringpool_sort_info& sort_info2) const +{ + 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; + for (size_t i = minlen; i > 0; --i, --p1, --p2) + { + if (*p1 != *p2) + return *p1 > *p2; + } + return len1 > len2; +} + +// Return whether s1 is a suffix of s2. + +template<typename Stringpool_char> +bool +Stringpool_template<Stringpool_char>::is_suffix(const Stringpool_char* s1, + size_t len1, + const Stringpool_char* s2, + size_t len2) +{ + if (len1 > len2) + return false; + return memcmp(s1, s2 + len2 - len1, len1 * sizeof(Stringpool_char)) == 0; +} + +// Turn the stringpool into an ELF strtab: determine the offsets of +// each string in the table. + +template<typename Stringpool_char> +void +Stringpool_template<Stringpool_char>::set_string_offsets() +{ + if (this->strtab_size_ != 0) + { + // We've already computed the offsets. + return; + } + + const size_t charsize = sizeof(Stringpool_char); + + // Offset 0 may be reserved for the empty string. + 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 we are not optimizing, the offsets are already assigned. + offset = this->offset_; + } + else + { + size_t count = this->string_set_.size(); + + std::vector<Stringpool_sort_info> 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<Stringpool_sort_info>::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() + && 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; +} + +// Get the offset of a string in the ELF strtab. The string must +// exist. + +template<typename Stringpool_char> +section_offset_type +Stringpool_template<Stringpool_char>::get_offset(const Stringpool_char* s) + const +{ + return this->get_offset_with_length(s, string_length(s)); +} + +template<typename Stringpool_char> +section_offset_type +Stringpool_template<Stringpool_char>::get_offset_with_length( + const Stringpool_char* s, + size_t length) const +{ + gold_assert(this->strtab_size_ != 0); + Hashkey hk(s, length); + typename String_set_type::const_iterator p = this->string_set_.find(hk); + if (p != this->string_set_.end()) + return this->key_to_offset_[p->second - 1]; + gold_unreachable(); +} + +// Write the ELF strtab into the buffer. + +template<typename Stringpool_char> +void +Stringpool_template<Stringpool_char>::write_to_buffer( + unsigned char* buffer, + section_size_type bufsize) +{ + gold_assert(this->strtab_size_ != 0); + gold_assert(bufsize >= this->strtab_size_); + if (this->zero_null_) + buffer[0] = '\0'; + for (typename String_set_type::const_iterator p = this->string_set_.begin(); + p != this->string_set_.end(); + ++p) + { + 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<section_size_type>(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<typename Stringpool_char> +void +Stringpool_template<Stringpool_char>::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<typename Stringpool_char> +void +Stringpool_template<Stringpool_char>::print_stats(const char* name) const +{ +#if 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. + +template +class Stringpool_template<char>; + +template +class Stringpool_template<uint16_t>; + +template +class Stringpool_template<uint32_t>; + +} // End namespace gold. |