| /* |
| * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "classfile/altHashing.hpp" |
| #include "classfile/compactHashtable.inline.hpp" |
| #include "classfile/javaClasses.inline.hpp" |
| #include "classfile/stringTable.hpp" |
| #include "classfile/systemDictionary.hpp" |
| #include "gc/shared/collectedHeap.inline.hpp" |
| #include "gc/shared/gcLocker.inline.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "memory/filemap.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/atomic.hpp" |
| #include "runtime/mutexLocker.hpp" |
| #include "utilities/hashtable.inline.hpp" |
| #include "utilities/macros.hpp" |
| #if INCLUDE_ALL_GCS |
| #include "gc/g1/g1CollectedHeap.hpp" |
| #include "gc/g1/g1SATBCardTableModRefBS.hpp" |
| #include "gc/g1/g1StringDedup.hpp" |
| #endif |
| |
| // the number of buckets a thread claims |
| const int ClaimChunkSize = 32; |
| |
| #ifdef ASSERT |
| class StableMemoryChecker : public StackObj { |
| enum { _bufsize = wordSize*4 }; |
| |
| address _region; |
| jint _size; |
| u1 _save_buf[_bufsize]; |
| |
| int sample(u1* save_buf) { |
| if (_size <= _bufsize) { |
| memcpy(save_buf, _region, _size); |
| return _size; |
| } else { |
| // copy head and tail |
| memcpy(&save_buf[0], _region, _bufsize/2); |
| memcpy(&save_buf[_bufsize/2], _region + _size - _bufsize/2, _bufsize/2); |
| return (_bufsize/2)*2; |
| } |
| } |
| |
| public: |
| StableMemoryChecker(const void* region, jint size) { |
| _region = (address) region; |
| _size = size; |
| sample(_save_buf); |
| } |
| |
| bool verify() { |
| u1 check_buf[sizeof(_save_buf)]; |
| int check_size = sample(check_buf); |
| return (0 == memcmp(_save_buf, check_buf, check_size)); |
| } |
| |
| void set_region(const void* region) { _region = (address) region; } |
| }; |
| #endif |
| |
| |
| // -------------------------------------------------------------------------- |
| StringTable* StringTable::_the_table = NULL; |
| bool StringTable::_ignore_shared_strings = false; |
| bool StringTable::_needs_rehashing = false; |
| |
| volatile int StringTable::_parallel_claimed_idx = 0; |
| |
| CompactHashtable<oop, char> StringTable::_shared_table; |
| |
| // Pick hashing algorithm |
| unsigned int StringTable::hash_string(const jchar* s, int len) { |
| return use_alternate_hashcode() ? AltHashing::murmur3_32(seed(), s, len) : |
| java_lang_String::hash_code(s, len); |
| } |
| |
| unsigned int StringTable::hash_string(oop string) { |
| EXCEPTION_MARK; |
| if (string == NULL) { |
| return hash_string((jchar*)NULL, 0); |
| } |
| ResourceMark rm(THREAD); |
| // All String oops are hashed as unicode |
| int length; |
| jchar* chars = java_lang_String::as_unicode_string(string, length, THREAD); |
| if (chars != NULL) { |
| return hash_string(chars, length); |
| } else { |
| vm_exit_out_of_memory(length, OOM_MALLOC_ERROR, "unable to create Unicode string for verification"); |
| return 0; |
| } |
| } |
| |
| oop StringTable::lookup_shared(jchar* name, int len) { |
| // java_lang_String::hash_code() was used to compute hash values in the shared table. Don't |
| // use the hash value from StringTable::hash_string() as it might use alternate hashcode. |
| return _shared_table.lookup((const char*)name, |
| java_lang_String::hash_code(name, len), len); |
| } |
| |
| oop StringTable::lookup_in_main_table(int index, jchar* name, |
| int len, unsigned int hash) { |
| int count = 0; |
| for (HashtableEntry<oop, mtSymbol>* l = bucket(index); l != NULL; l = l->next()) { |
| count++; |
| if (l->hash() == hash) { |
| if (java_lang_String::equals(l->literal(), name, len)) { |
| return l->literal(); |
| } |
| } |
| } |
| // If the bucket size is too deep check if this hash code is insufficient. |
| if (count >= rehash_count && !needs_rehashing()) { |
| _needs_rehashing = check_rehash_table(count); |
| } |
| return NULL; |
| } |
| |
| |
| oop StringTable::basic_add(int index_arg, Handle string, jchar* name, |
| int len, unsigned int hashValue_arg, TRAPS) { |
| |
| assert(java_lang_String::equals(string(), name, len), |
| "string must be properly initialized"); |
| // Cannot hit a safepoint in this function because the "this" pointer can move. |
| NoSafepointVerifier nsv; |
| |
| // Check if the symbol table has been rehashed, if so, need to recalculate |
| // the hash value and index before second lookup. |
| unsigned int hashValue; |
| int index; |
| if (use_alternate_hashcode()) { |
| hashValue = hash_string(name, len); |
| index = hash_to_index(hashValue); |
| } else { |
| hashValue = hashValue_arg; |
| index = index_arg; |
| } |
| |
| // Since look-up was done lock-free, we need to check if another |
| // thread beat us in the race to insert the symbol. |
| |
| // No need to lookup the shared table from here since the caller (intern()) already did |
| oop test = lookup_in_main_table(index, name, len, hashValue); // calls lookup(u1*, int) |
| if (test != NULL) { |
| // Entry already added |
| return test; |
| } |
| |
| HashtableEntry<oop, mtSymbol>* entry = new_entry(hashValue, string()); |
| add_entry(index, entry); |
| return string(); |
| } |
| |
| |
| oop StringTable::lookup(Symbol* symbol) { |
| ResourceMark rm; |
| int length; |
| jchar* chars = symbol->as_unicode(length); |
| return lookup(chars, length); |
| } |
| |
| // Tell the GC that this string was looked up in the StringTable. |
| static void ensure_string_alive(oop string) { |
| // A lookup in the StringTable could return an object that was previously |
| // considered dead. The SATB part of G1 needs to get notified about this |
| // potential resurrection, otherwise the marking might not find the object. |
| #if INCLUDE_ALL_GCS |
| if (UseG1GC && string != NULL) { |
| G1SATBCardTableModRefBS::enqueue(string); |
| } |
| #endif |
| } |
| |
| oop StringTable::lookup(jchar* name, int len) { |
| oop string = lookup_shared(name, len); |
| if (string != NULL) { |
| return string; |
| } |
| |
| unsigned int hash = hash_string(name, len); |
| int index = the_table()->hash_to_index(hash); |
| string = the_table()->lookup_in_main_table(index, name, len, hash); |
| |
| ensure_string_alive(string); |
| |
| return string; |
| } |
| |
| oop StringTable::intern(Handle string_or_null, jchar* name, |
| int len, TRAPS) { |
| oop found_string = lookup_shared(name, len); |
| if (found_string != NULL) { |
| return found_string; |
| } |
| |
| unsigned int hashValue = hash_string(name, len); |
| int index = the_table()->hash_to_index(hashValue); |
| found_string = the_table()->lookup_in_main_table(index, name, len, hashValue); |
| |
| // Found |
| if (found_string != NULL) { |
| if (found_string != string_or_null()) { |
| ensure_string_alive(found_string); |
| } |
| return found_string; |
| } |
| |
| debug_only(StableMemoryChecker smc(name, len * sizeof(name[0]))); |
| assert(!Universe::heap()->is_in_reserved(name), |
| "proposed name of symbol must be stable"); |
| |
| Handle string; |
| // try to reuse the string if possible |
| if (!string_or_null.is_null()) { |
| string = string_or_null; |
| } else { |
| string = java_lang_String::create_from_unicode(name, len, CHECK_NULL); |
| } |
| |
| #if INCLUDE_ALL_GCS |
| if (G1StringDedup::is_enabled()) { |
| // Deduplicate the string before it is interned. Note that we should never |
| // deduplicate a string after it has been interned. Doing so will counteract |
| // compiler optimizations done on e.g. interned string literals. |
| G1StringDedup::deduplicate(string()); |
| } |
| #endif |
| |
| // Grab the StringTable_lock before getting the_table() because it could |
| // change at safepoint. |
| oop added_or_found; |
| { |
| MutexLocker ml(StringTable_lock, THREAD); |
| // Otherwise, add to symbol to table |
| added_or_found = the_table()->basic_add(index, string, name, len, |
| hashValue, CHECK_NULL); |
| } |
| |
| if (added_or_found != string()) { |
| ensure_string_alive(added_or_found); |
| } |
| |
| return added_or_found; |
| } |
| |
| oop StringTable::intern(Symbol* symbol, TRAPS) { |
| if (symbol == NULL) return NULL; |
| ResourceMark rm(THREAD); |
| int length; |
| jchar* chars = symbol->as_unicode(length); |
| Handle string; |
| oop result = intern(string, chars, length, CHECK_NULL); |
| return result; |
| } |
| |
| |
| oop StringTable::intern(oop string, TRAPS) |
| { |
| if (string == NULL) return NULL; |
| ResourceMark rm(THREAD); |
| int length; |
| Handle h_string (THREAD, string); |
| jchar* chars = java_lang_String::as_unicode_string(string, length, CHECK_NULL); |
| oop result = intern(h_string, chars, length, CHECK_NULL); |
| return result; |
| } |
| |
| |
| oop StringTable::intern(const char* utf8_string, TRAPS) { |
| if (utf8_string == NULL) return NULL; |
| ResourceMark rm(THREAD); |
| int length = UTF8::unicode_length(utf8_string); |
| jchar* chars = NEW_RESOURCE_ARRAY(jchar, length); |
| UTF8::convert_to_unicode(utf8_string, chars, length); |
| Handle string; |
| oop result = intern(string, chars, length, CHECK_NULL); |
| return result; |
| } |
| |
| void StringTable::unlink_or_oops_do(BoolObjectClosure* is_alive, OopClosure* f, int* processed, int* removed) { |
| buckets_unlink_or_oops_do(is_alive, f, 0, the_table()->table_size(), processed, removed); |
| } |
| |
| void StringTable::possibly_parallel_unlink_or_oops_do(BoolObjectClosure* is_alive, OopClosure* f, int* processed, int* removed) { |
| // Readers of the table are unlocked, so we should only be removing |
| // entries at a safepoint. |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
| const int limit = the_table()->table_size(); |
| |
| for (;;) { |
| // Grab next set of buckets to scan |
| int start_idx = Atomic::add(ClaimChunkSize, &_parallel_claimed_idx) - ClaimChunkSize; |
| if (start_idx >= limit) { |
| // End of table |
| break; |
| } |
| |
| int end_idx = MIN2(limit, start_idx + ClaimChunkSize); |
| buckets_unlink_or_oops_do(is_alive, f, start_idx, end_idx, processed, removed); |
| } |
| } |
| |
| void StringTable::buckets_oops_do(OopClosure* f, int start_idx, int end_idx) { |
| const int limit = the_table()->table_size(); |
| |
| assert(0 <= start_idx && start_idx <= limit, |
| "start_idx (%d) is out of bounds", start_idx); |
| assert(0 <= end_idx && end_idx <= limit, |
| "end_idx (%d) is out of bounds", end_idx); |
| assert(start_idx <= end_idx, |
| "Index ordering: start_idx=%d, end_idx=%d", |
| start_idx, end_idx); |
| |
| for (int i = start_idx; i < end_idx; i += 1) { |
| HashtableEntry<oop, mtSymbol>* entry = the_table()->bucket(i); |
| while (entry != NULL) { |
| assert(!entry->is_shared(), "CDS not used for the StringTable"); |
| |
| f->do_oop((oop*)entry->literal_addr()); |
| |
| entry = entry->next(); |
| } |
| } |
| } |
| |
| void StringTable::buckets_unlink_or_oops_do(BoolObjectClosure* is_alive, OopClosure* f, int start_idx, int end_idx, int* processed, int* removed) { |
| const int limit = the_table()->table_size(); |
| |
| assert(0 <= start_idx && start_idx <= limit, |
| "start_idx (%d) is out of bounds", start_idx); |
| assert(0 <= end_idx && end_idx <= limit, |
| "end_idx (%d) is out of bounds", end_idx); |
| assert(start_idx <= end_idx, |
| "Index ordering: start_idx=%d, end_idx=%d", |
| start_idx, end_idx); |
| |
| for (int i = start_idx; i < end_idx; ++i) { |
| HashtableEntry<oop, mtSymbol>** p = the_table()->bucket_addr(i); |
| HashtableEntry<oop, mtSymbol>* entry = the_table()->bucket(i); |
| while (entry != NULL) { |
| assert(!entry->is_shared(), "CDS not used for the StringTable"); |
| |
| if (is_alive->do_object_b(entry->literal())) { |
| if (f != NULL) { |
| f->do_oop((oop*)entry->literal_addr()); |
| } |
| p = entry->next_addr(); |
| } else { |
| *p = entry->next(); |
| the_table()->free_entry(entry); |
| (*removed)++; |
| } |
| (*processed)++; |
| entry = *p; |
| } |
| } |
| } |
| |
| void StringTable::oops_do(OopClosure* f) { |
| buckets_oops_do(f, 0, the_table()->table_size()); |
| } |
| |
| void StringTable::possibly_parallel_oops_do(OopClosure* f) { |
| const int limit = the_table()->table_size(); |
| |
| for (;;) { |
| // Grab next set of buckets to scan |
| int start_idx = Atomic::add(ClaimChunkSize, &_parallel_claimed_idx) - ClaimChunkSize; |
| if (start_idx >= limit) { |
| // End of table |
| break; |
| } |
| |
| int end_idx = MIN2(limit, start_idx + ClaimChunkSize); |
| buckets_oops_do(f, start_idx, end_idx); |
| } |
| } |
| |
| // This verification is part of Universe::verify() and needs to be quick. |
| // See StringTable::verify_and_compare() below for exhaustive verification. |
| void StringTable::verify() { |
| for (int i = 0; i < the_table()->table_size(); ++i) { |
| HashtableEntry<oop, mtSymbol>* p = the_table()->bucket(i); |
| for ( ; p != NULL; p = p->next()) { |
| oop s = p->literal(); |
| guarantee(s != NULL, "interned string is NULL"); |
| unsigned int h = hash_string(s); |
| guarantee(p->hash() == h, "broken hash in string table entry"); |
| guarantee(the_table()->hash_to_index(h) == i, |
| "wrong index in string table"); |
| } |
| } |
| } |
| |
| void StringTable::dump(outputStream* st, bool verbose) { |
| if (!verbose) { |
| the_table()->dump_table(st, "StringTable"); |
| } else { |
| Thread* THREAD = Thread::current(); |
| st->print_cr("VERSION: 1.1"); |
| for (int i = 0; i < the_table()->table_size(); ++i) { |
| HashtableEntry<oop, mtSymbol>* p = the_table()->bucket(i); |
| for ( ; p != NULL; p = p->next()) { |
| oop s = p->literal(); |
| typeArrayOop value = java_lang_String::value(s); |
| int length = java_lang_String::length(s); |
| bool is_latin1 = java_lang_String::is_latin1(s); |
| |
| if (length <= 0) { |
| st->print("%d: ", length); |
| } else { |
| ResourceMark rm(THREAD); |
| int utf8_length = length; |
| char* utf8_string; |
| |
| if (!is_latin1) { |
| jchar* chars = value->char_at_addr(0); |
| utf8_string = UNICODE::as_utf8(chars, utf8_length); |
| } else { |
| jbyte* bytes = value->byte_at_addr(0); |
| utf8_string = UNICODE::as_utf8(bytes, utf8_length); |
| } |
| |
| st->print("%d: ", utf8_length); |
| HashtableTextDump::put_utf8(st, utf8_string, utf8_length); |
| } |
| st->cr(); |
| } |
| } |
| } |
| } |
| |
| StringTable::VerifyRetTypes StringTable::compare_entries( |
| int bkt1, int e_cnt1, |
| HashtableEntry<oop, mtSymbol>* e_ptr1, |
| int bkt2, int e_cnt2, |
| HashtableEntry<oop, mtSymbol>* e_ptr2) { |
| // These entries are sanity checked by verify_and_compare_entries() |
| // before this function is called. |
| oop str1 = e_ptr1->literal(); |
| oop str2 = e_ptr2->literal(); |
| |
| if (str1 == str2) { |
| tty->print_cr("ERROR: identical oop values (0x" PTR_FORMAT ") " |
| "in entry @ bucket[%d][%d] and entry @ bucket[%d][%d]", |
| p2i(str1), bkt1, e_cnt1, bkt2, e_cnt2); |
| return _verify_fail_continue; |
| } |
| |
| if (java_lang_String::equals(str1, str2)) { |
| tty->print_cr("ERROR: identical String values in entry @ " |
| "bucket[%d][%d] and entry @ bucket[%d][%d]", |
| bkt1, e_cnt1, bkt2, e_cnt2); |
| return _verify_fail_continue; |
| } |
| |
| return _verify_pass; |
| } |
| |
| StringTable::VerifyRetTypes StringTable::verify_entry(int bkt, int e_cnt, |
| HashtableEntry<oop, mtSymbol>* e_ptr, |
| StringTable::VerifyMesgModes mesg_mode) { |
| |
| VerifyRetTypes ret = _verify_pass; // be optimistic |
| |
| oop str = e_ptr->literal(); |
| if (str == NULL) { |
| if (mesg_mode == _verify_with_mesgs) { |
| tty->print_cr("ERROR: NULL oop value in entry @ bucket[%d][%d]", bkt, |
| e_cnt); |
| } |
| // NULL oop means no more verifications are possible |
| return _verify_fail_done; |
| } |
| |
| if (str->klass() != SystemDictionary::String_klass()) { |
| if (mesg_mode == _verify_with_mesgs) { |
| tty->print_cr("ERROR: oop is not a String in entry @ bucket[%d][%d]", |
| bkt, e_cnt); |
| } |
| // not a String means no more verifications are possible |
| return _verify_fail_done; |
| } |
| |
| unsigned int h = hash_string(str); |
| if (e_ptr->hash() != h) { |
| if (mesg_mode == _verify_with_mesgs) { |
| tty->print_cr("ERROR: broken hash value in entry @ bucket[%d][%d], " |
| "bkt_hash=%d, str_hash=%d", bkt, e_cnt, e_ptr->hash(), h); |
| } |
| ret = _verify_fail_continue; |
| } |
| |
| if (the_table()->hash_to_index(h) != bkt) { |
| if (mesg_mode == _verify_with_mesgs) { |
| tty->print_cr("ERROR: wrong index value for entry @ bucket[%d][%d], " |
| "str_hash=%d, hash_to_index=%d", bkt, e_cnt, h, |
| the_table()->hash_to_index(h)); |
| } |
| ret = _verify_fail_continue; |
| } |
| |
| return ret; |
| } |
| |
| // See StringTable::verify() above for the quick verification that is |
| // part of Universe::verify(). This verification is exhaustive and |
| // reports on every issue that is found. StringTable::verify() only |
| // reports on the first issue that is found. |
| // |
| // StringTable::verify_entry() checks: |
| // - oop value != NULL (same as verify()) |
| // - oop value is a String |
| // - hash(String) == hash in entry (same as verify()) |
| // - index for hash == index of entry (same as verify()) |
| // |
| // StringTable::compare_entries() checks: |
| // - oops are unique across all entries |
| // - String values are unique across all entries |
| // |
| int StringTable::verify_and_compare_entries() { |
| assert(StringTable_lock->is_locked(), "sanity check"); |
| |
| int fail_cnt = 0; |
| |
| // first, verify all the entries individually: |
| for (int bkt = 0; bkt < the_table()->table_size(); bkt++) { |
| HashtableEntry<oop, mtSymbol>* e_ptr = the_table()->bucket(bkt); |
| for (int e_cnt = 0; e_ptr != NULL; e_ptr = e_ptr->next(), e_cnt++) { |
| VerifyRetTypes ret = verify_entry(bkt, e_cnt, e_ptr, _verify_with_mesgs); |
| if (ret != _verify_pass) { |
| fail_cnt++; |
| } |
| } |
| } |
| |
| // Optimization: if the above check did not find any failures, then |
| // the comparison loop below does not need to call verify_entry() |
| // before calling compare_entries(). If there were failures, then we |
| // have to call verify_entry() to see if the entry can be passed to |
| // compare_entries() safely. When we call verify_entry() in the loop |
| // below, we do so quietly to void duplicate messages and we don't |
| // increment fail_cnt because the failures have already been counted. |
| bool need_entry_verify = (fail_cnt != 0); |
| |
| // second, verify all entries relative to each other: |
| for (int bkt1 = 0; bkt1 < the_table()->table_size(); bkt1++) { |
| HashtableEntry<oop, mtSymbol>* e_ptr1 = the_table()->bucket(bkt1); |
| for (int e_cnt1 = 0; e_ptr1 != NULL; e_ptr1 = e_ptr1->next(), e_cnt1++) { |
| if (need_entry_verify) { |
| VerifyRetTypes ret = verify_entry(bkt1, e_cnt1, e_ptr1, |
| _verify_quietly); |
| if (ret == _verify_fail_done) { |
| // cannot use the current entry to compare against other entries |
| continue; |
| } |
| } |
| |
| for (int bkt2 = bkt1; bkt2 < the_table()->table_size(); bkt2++) { |
| HashtableEntry<oop, mtSymbol>* e_ptr2 = the_table()->bucket(bkt2); |
| int e_cnt2; |
| for (e_cnt2 = 0; e_ptr2 != NULL; e_ptr2 = e_ptr2->next(), e_cnt2++) { |
| if (bkt1 == bkt2 && e_cnt2 <= e_cnt1) { |
| // skip the entries up to and including the one that |
| // we're comparing against |
| continue; |
| } |
| |
| if (need_entry_verify) { |
| VerifyRetTypes ret = verify_entry(bkt2, e_cnt2, e_ptr2, |
| _verify_quietly); |
| if (ret == _verify_fail_done) { |
| // cannot compare against this entry |
| continue; |
| } |
| } |
| |
| // compare two entries, report and count any failures: |
| if (compare_entries(bkt1, e_cnt1, e_ptr1, bkt2, e_cnt2, e_ptr2) |
| != _verify_pass) { |
| fail_cnt++; |
| } |
| } |
| } |
| } |
| } |
| return fail_cnt; |
| } |
| |
| // Create a new table and using alternate hash code, populate the new table |
| // with the existing strings. Set flag to use the alternate hash code afterwards. |
| void StringTable::rehash_table() { |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
| // This should never happen with -Xshare:dump but it might in testing mode. |
| if (DumpSharedSpaces) return; |
| StringTable* new_table = new StringTable(); |
| |
| // Rehash the table |
| the_table()->move_to(new_table); |
| |
| // Delete the table and buckets (entries are reused in new table). |
| delete _the_table; |
| // Don't check if we need rehashing until the table gets unbalanced again. |
| // Then rehash with a new global seed. |
| _needs_rehashing = false; |
| _the_table = new_table; |
| } |
| |
| // Utility for dumping strings |
| StringtableDCmd::StringtableDCmd(outputStream* output, bool heap) : |
| DCmdWithParser(output, heap), |
| _verbose("-verbose", "Dump the content of each string in the table", |
| "BOOLEAN", false, "false") { |
| _dcmdparser.add_dcmd_option(&_verbose); |
| } |
| |
| void StringtableDCmd::execute(DCmdSource source, TRAPS) { |
| VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpStrings, |
| _verbose.value()); |
| VMThread::execute(&dumper); |
| } |
| |
| int StringtableDCmd::num_arguments() { |
| ResourceMark rm; |
| StringtableDCmd* dcmd = new StringtableDCmd(NULL, false); |
| if (dcmd != NULL) { |
| DCmdMark mark(dcmd); |
| return dcmd->_dcmdparser.num_arguments(); |
| } else { |
| return 0; |
| } |
| } |
| |
| // Sharing |
| bool StringTable::copy_shared_string(GrowableArray<MemRegion> *string_space, |
| CompactStringTableWriter* writer) { |
| #if INCLUDE_CDS && INCLUDE_ALL_GCS && defined(_LP64) && !defined(_WINDOWS) |
| assert(UseG1GC, "Only support G1 GC"); |
| assert(UseCompressedOops && UseCompressedClassPointers, |
| "Only support UseCompressedOops and UseCompressedClassPointers enabled"); |
| |
| Thread* THREAD = Thread::current(); |
| G1CollectedHeap::heap()->begin_archive_alloc_range(); |
| for (int i = 0; i < the_table()->table_size(); ++i) { |
| HashtableEntry<oop, mtSymbol>* bucket = the_table()->bucket(i); |
| for ( ; bucket != NULL; bucket = bucket->next()) { |
| oop s = bucket->literal(); |
| unsigned int hash = java_lang_String::hash_code(s); |
| if (hash == 0) { |
| continue; |
| } |
| |
| // allocate the new 'value' array first |
| typeArrayOop v = java_lang_String::value(s); |
| int v_len = v->size(); |
| typeArrayOop new_v; |
| if (G1CollectedHeap::heap()->is_archive_alloc_too_large(v_len)) { |
| continue; // skip the current String. The 'value' array is too large to handle |
| } else { |
| new_v = (typeArrayOop)G1CollectedHeap::heap()->archive_mem_allocate(v_len); |
| if (new_v == NULL) { |
| return false; // allocation failed |
| } |
| } |
| // now allocate the new String object |
| int s_len = s->size(); |
| oop new_s = (oop)G1CollectedHeap::heap()->archive_mem_allocate(s_len); |
| if (new_s == NULL) { |
| return false; |
| } |
| |
| s->identity_hash(); |
| v->identity_hash(); |
| |
| // copy the objects' data |
| Copy::aligned_disjoint_words((HeapWord*)s, (HeapWord*)new_s, s_len); |
| Copy::aligned_disjoint_words((HeapWord*)v, (HeapWord*)new_v, v_len); |
| |
| // adjust the pointer to the 'value' field in the new String oop. Also pre-compute and set the |
| // 'hash' field. That avoids "write" to the shared strings at runtime by the deduplication process. |
| java_lang_String::set_value_raw(new_s, new_v); |
| if (java_lang_String::hash(new_s) == 0) { |
| java_lang_String::set_hash(new_s, hash); |
| } |
| |
| // add to the compact table |
| writer->add(hash, new_s); |
| } |
| } |
| |
| G1CollectedHeap::heap()->end_archive_alloc_range(string_space, os::vm_allocation_granularity()); |
| assert(string_space->length() <= 2, "sanity"); |
| #endif |
| return true; |
| } |
| |
| void StringTable::serialize(SerializeClosure* soc, GrowableArray<MemRegion> *string_space, |
| size_t* space_size) { |
| #if INCLUDE_CDS && defined(_LP64) && !defined(_WINDOWS) |
| _shared_table.reset(); |
| if (soc->writing()) { |
| if (!(UseG1GC && UseCompressedOops && UseCompressedClassPointers)) { |
| if (PrintSharedSpaces) { |
| tty->print_cr( |
| "Shared strings are excluded from the archive as UseG1GC, " |
| "UseCompressedOops and UseCompressedClassPointers are required." |
| "Current settings: UseG1GC=%s, UseCompressedOops=%s, UseCompressedClassPointers=%s.", |
| BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedOops), |
| BOOL_TO_STR(UseCompressedClassPointers)); |
| } |
| } else { |
| int num_buckets = the_table()->number_of_entries() / |
| SharedSymbolTableBucketSize; |
| // calculation of num_buckets can result in zero buckets, we need at least one |
| CompactStringTableWriter writer(num_buckets > 1 ? num_buckets : 1, |
| &MetaspaceShared::stats()->string); |
| |
| // Copy the interned strings into the "string space" within the java heap |
| if (copy_shared_string(string_space, &writer)) { |
| for (int i = 0; i < string_space->length(); i++) { |
| *space_size += string_space->at(i).byte_size(); |
| } |
| writer.dump(&_shared_table); |
| } |
| } |
| } |
| |
| _shared_table.set_type(CompactHashtable<oop, char>::_string_table); |
| _shared_table.serialize(soc); |
| |
| if (soc->writing()) { |
| _shared_table.reset(); // Sanity. Make sure we don't use the shared table at dump time |
| } else if (_ignore_shared_strings) { |
| _shared_table.reset(); |
| } |
| #endif |
| } |
| |
| void StringTable::shared_oops_do(OopClosure* f) { |
| #if INCLUDE_CDS && defined(_LP64) && !defined(_WINDOWS) |
| _shared_table.oops_do(f); |
| #endif |
| } |
| |
