--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/utilities/hashtable.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,270 @@
+/*
+ * Copyright 2003-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_hashtable.cpp.incl"
+
+HS_DTRACE_PROBE_DECL4(hs_private, hashtable__new_entry,
+ void*, unsigned int, oop, void*);
+
+// This is a generic hashtable, designed to be used for the symbol
+// and string tables.
+//
+// It is implemented as an open hash table with a fixed number of buckets.
+//
+// %note:
+// - HashtableEntrys are allocated in blocks to reduce the space overhead.
+
+BasicHashtableEntry* BasicHashtable::new_entry(unsigned int hashValue) {
+ BasicHashtableEntry* entry;
+
+ if (_free_list) {
+ entry = _free_list;
+ _free_list = _free_list->next();
+ } else {
+ const int block_size = 500;
+ if (_first_free_entry == _end_block) {
+ int len = _entry_size * block_size;
+ _first_free_entry = NEW_C_HEAP_ARRAY(char, len);
+ _end_block = _first_free_entry + len;
+ }
+ entry = (BasicHashtableEntry*)_first_free_entry;
+ _first_free_entry += _entry_size;
+ }
+
+ entry->set_hash(hashValue);
+ return entry;
+}
+
+
+HashtableEntry* Hashtable::new_entry(unsigned int hashValue, oop obj) {
+ HashtableEntry* entry;
+
+ entry = (HashtableEntry*)BasicHashtable::new_entry(hashValue);
+ entry->set_literal(obj); // clears literal string field
+ HS_DTRACE_PROBE4(hs_private, hashtable__new_entry,
+ this, hashValue, obj, entry);
+ return entry;
+}
+
+
+// GC support
+
+void Hashtable::unlink(BoolObjectClosure* is_alive) {
+ // 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");
+ for (int i = 0; i < table_size(); ++i) {
+ for (HashtableEntry** p = bucket_addr(i); *p != NULL; ) {
+ HashtableEntry* entry = *p;
+ if (entry->is_shared()) {
+ break;
+ }
+ assert(entry->literal() != NULL, "just checking");
+ if (is_alive->do_object_b(entry->literal())) {
+ p = entry->next_addr();
+ } else {
+ *p = entry->next();
+ free_entry(entry);
+ }
+ }
+ }
+}
+
+
+void Hashtable::oops_do(OopClosure* f) {
+ for (int i = 0; i < table_size(); ++i) {
+ HashtableEntry** p = bucket_addr(i);
+ HashtableEntry* entry = bucket(i);
+ while (entry != NULL) {
+ f->do_oop(entry->literal_addr());
+
+ // Did the closure remove the literal from the table?
+ if (entry->literal() == NULL) {
+ assert(!entry->is_shared(), "immutable hashtable entry?");
+ *p = entry->next();
+ free_entry(entry);
+ } else {
+ p = entry->next_addr();
+ }
+ entry = (HashtableEntry*)HashtableEntry::make_ptr(*p);
+ }
+ }
+}
+
+
+// Reverse the order of elements in the hash buckets.
+
+void BasicHashtable::reverse() {
+
+ for (int i = 0; i < _table_size; ++i) {
+ BasicHashtableEntry* new_list = NULL;
+ BasicHashtableEntry* p = bucket(i);
+ while (p != NULL) {
+ BasicHashtableEntry* next = p->next();
+ p->set_next(new_list);
+ new_list = p;
+ p = next;
+ }
+ *bucket_addr(i) = new_list;
+ }
+}
+
+
+// Copy the table to the shared space.
+
+void BasicHashtable::copy_table(char** top, char* end) {
+
+ // Dump the hash table entries.
+
+ intptr_t *plen = (intptr_t*)(*top);
+ *top += sizeof(*plen);
+
+ int i;
+ for (i = 0; i < _table_size; ++i) {
+ for (BasicHashtableEntry** p = _buckets[i].entry_addr();
+ *p != NULL;
+ p = (*p)->next_addr()) {
+ if (*top + entry_size() > end) {
+ warning("\nThe shared miscellaneous data space is not large "
+ "enough to \npreload requested classes. Use "
+ "-XX:SharedMiscDataSize= to increase \nthe initial "
+ "size of the miscellaneous data space.\n");
+ exit(2);
+ }
+ *p = (BasicHashtableEntry*)memcpy(*top, *p, entry_size());
+ *top += entry_size();
+ }
+ }
+ *plen = (char*)(*top) - (char*)plen - sizeof(*plen);
+
+ // Set the shared bit.
+
+ for (i = 0; i < _table_size; ++i) {
+ for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) {
+ p->set_shared();
+ }
+ }
+}
+
+
+
+// Reverse the order of elements in the hash buckets.
+
+void Hashtable::reverse(void* boundary) {
+
+ for (int i = 0; i < table_size(); ++i) {
+ HashtableEntry* high_list = NULL;
+ HashtableEntry* low_list = NULL;
+ HashtableEntry* last_low_entry = NULL;
+ HashtableEntry* p = bucket(i);
+ while (p != NULL) {
+ HashtableEntry* next = p->next();
+ if ((void*)p->literal() >= boundary) {
+ p->set_next(high_list);
+ high_list = p;
+ } else {
+ p->set_next(low_list);
+ low_list = p;
+ if (last_low_entry == NULL) {
+ last_low_entry = p;
+ }
+ }
+ p = next;
+ }
+ if (low_list != NULL) {
+ *bucket_addr(i) = low_list;
+ last_low_entry->set_next(high_list);
+ } else {
+ *bucket_addr(i) = high_list;
+ }
+ }
+}
+
+
+// Dump the hash table buckets.
+
+void BasicHashtable::copy_buckets(char** top, char* end) {
+ intptr_t len = _table_size * sizeof(HashtableBucket);
+ *(intptr_t*)(*top) = len;
+ *top += sizeof(intptr_t);
+
+ *(intptr_t*)(*top) = _number_of_entries;
+ *top += sizeof(intptr_t);
+
+ if (*top + len > end) {
+ warning("\nThe shared miscellaneous data space is not large "
+ "enough to \npreload requested classes. Use "
+ "-XX:SharedMiscDataSize= to increase \nthe initial "
+ "size of the miscellaneous data space.\n");
+ exit(2);
+ }
+ _buckets = (HashtableBucket*)memcpy(*top, _buckets, len);
+ *top += len;
+}
+
+
+#ifndef PRODUCT
+
+void Hashtable::print() {
+ ResourceMark rm;
+
+ for (int i = 0; i < table_size(); i++) {
+ HashtableEntry* entry = bucket(i);
+ while(entry != NULL) {
+ tty->print("%d : ", i);
+ entry->literal()->print();
+ tty->cr();
+ entry = entry->next();
+ }
+ }
+}
+
+
+void BasicHashtable::verify() {
+ int count = 0;
+ for (int i = 0; i < table_size(); i++) {
+ for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) {
+ ++count;
+ }
+ }
+ assert(count == number_of_entries(), "number of hashtable entries incorrect");
+}
+
+
+#endif // PRODUCT
+
+
+#ifdef ASSERT
+
+void BasicHashtable::verify_lookup_length(double load) {
+ if ((double)_lookup_length / (double)_lookup_count > load * 2.0) {
+ warning("Performance bug: SystemDictionary lookup_count=%d "
+ "lookup_length=%d average=%lf load=%f",
+ _lookup_count, _lookup_length,
+ (double) _lookup_length / _lookup_count, load);
+ }
+}
+
+#endif