--- a/hotspot/src/share/vm/classfile/symbolTable.cpp Wed May 07 06:03:31 2014 -0700
+++ b/hotspot/src/share/vm/classfile/symbolTable.cpp Wed May 07 14:16:45 2014 -0500
@@ -35,11 +35,6 @@
#include "oops/oop.inline2.hpp"
#include "runtime/mutexLocker.hpp"
#include "utilities/hashtable.inline.hpp"
-#if INCLUDE_ALL_GCS
-#include "gc_implementation/g1/g1StringDedup.hpp"
-#endif
-
-// --------------------------------------------------------------------------
// the number of buckets a thread claims
const int ClaimChunkSize = 32;
@@ -587,493 +582,3 @@
}
}
#endif // PRODUCT
-
-// --------------------------------------------------------------------------
-
-#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::_needs_rehashing = false;
-
-volatile int StringTable::_parallel_claimed_idx = 0;
-
-// 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);
-}
-
-oop StringTable::lookup(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 >= BasicHashtable<mtSymbol>::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.
- No_Safepoint_Verifier 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.
-
- oop test = lookup(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);
-}
-
-
-oop StringTable::lookup(jchar* name, int len) {
- unsigned int hash = hash_string(name, len);
- int index = the_table()->hash_to_index(hash);
- return the_table()->lookup(index, name, len, hash);
-}
-
-
-oop StringTable::intern(Handle string_or_null, jchar* name,
- int len, TRAPS) {
- unsigned int hashValue = hash_string(name, len);
- int index = the_table()->hash_to_index(hashValue);
- oop found_string = the_table()->lookup(index, name, len, hashValue);
-
- // Found
- if (found_string != NULL) 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.
- MutexLocker ml(StringTable_lock, THREAD);
-
- // Otherwise, add to symbol to table
- return the_table()->basic_add(index, string, name, len,
- hashValue, CHECK_NULL);
-}
-
-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,
- err_msg("start_idx (%d) is out of bounds", start_idx));
- assert(0 <= end_idx && end_idx <= limit,
- err_msg("end_idx (%d) is out of bounds", end_idx));
- assert(start_idx <= end_idx,
- err_msg("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,
- err_msg("start_idx (%d) is out of bounds", start_idx));
- assert(0 <= end_idx && end_idx <= limit,
- err_msg("end_idx (%d) is out of bounds", end_idx));
- assert(start_idx <= end_idx,
- err_msg("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 = java_lang_String::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) {
- the_table()->dump_table(st, "StringTable");
-}
-
-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]",
- (void *)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 = java_lang_String::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;
-}