1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/classfile/altHashing.cpp Wed Jun 13 19:52:59 2012 -0400
1.3 @@ -0,0 +1,304 @@
1.4 +/*
1.5 + * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "classfile/altHashing.hpp"
1.30 +#include "classfile/symbolTable.hpp"
1.31 +#include "classfile/systemDictionary.hpp"
1.32 +#include "oops/markOop.hpp"
1.33 +#include "runtime/thread.hpp"
1.34 +
1.35 +// Get the hash code of the classes mirror if it exists, otherwise just
1.36 +// return a random number, which is one of the possible hash code used for
1.37 +// objects. We don't want to call the synchronizer hash code to install
1.38 +// this value because it may safepoint.
1.39 +intptr_t object_hash(klassOop k) {
1.40 + intptr_t hc = k->java_mirror()->mark()->hash();
1.41 + return hc != markOopDesc::no_hash ? hc : os::random();
1.42 +}
1.43 +
1.44 +// Seed value used for each alternative hash calculated.
1.45 +jint AltHashing::compute_seed() {
1.46 + jlong nanos = os::javaTimeNanos();
1.47 + jlong now = os::javaTimeMillis();
1.48 + jint SEED_MATERIAL[8] = {
1.49 + (jint) object_hash(SystemDictionary::String_klass()),
1.50 + (jint) object_hash(SystemDictionary::System_klass()),
1.51 + (jint) os::random(), // current thread isn't a java thread
1.52 + (jint) (((julong)nanos) >> 32),
1.53 + (jint) nanos,
1.54 + (jint) (((julong)now) >> 32),
1.55 + (jint) now,
1.56 + (jint) (os::javaTimeNanos() >> 2)
1.57 + };
1.58 +
1.59 + return murmur3_32(SEED_MATERIAL, 8);
1.60 +}
1.61 +
1.62 +
1.63 +// Murmur3 hashing for Symbol
1.64 +jint AltHashing::murmur3_32(jint seed, const jbyte* data, int len) {
1.65 + jint h1 = seed;
1.66 + int count = len;
1.67 + int offset = 0;
1.68 +
1.69 + // body
1.70 + while (count >= 4) {
1.71 + jint k1 = (data[offset] & 0x0FF)
1.72 + | (data[offset + 1] & 0x0FF) << 8
1.73 + | (data[offset + 2] & 0x0FF) << 16
1.74 + | data[offset + 3] << 24;
1.75 +
1.76 + count -= 4;
1.77 + offset += 4;
1.78 +
1.79 + k1 *= 0xcc9e2d51;
1.80 + k1 = Integer_rotateLeft(k1, 15);
1.81 + k1 *= 0x1b873593;
1.82 +
1.83 + h1 ^= k1;
1.84 + h1 = Integer_rotateLeft(h1, 13);
1.85 + h1 = h1 * 5 + 0xe6546b64;
1.86 + }
1.87 +
1.88 + // tail
1.89 +
1.90 + if (count > 0) {
1.91 + jint k1 = 0;
1.92 +
1.93 + switch (count) {
1.94 + case 3:
1.95 + k1 ^= (data[offset + 2] & 0xff) << 16;
1.96 + // fall through
1.97 + case 2:
1.98 + k1 ^= (data[offset + 1] & 0xff) << 8;
1.99 + // fall through
1.100 + case 1:
1.101 + k1 ^= (data[offset] & 0xff);
1.102 + // fall through
1.103 + default:
1.104 + k1 *= 0xcc9e2d51;
1.105 + k1 = Integer_rotateLeft(k1, 15);
1.106 + k1 *= 0x1b873593;
1.107 + h1 ^= k1;
1.108 + }
1.109 + }
1.110 +
1.111 + // finalization
1.112 + h1 ^= len;
1.113 +
1.114 + // finalization mix force all bits of a hash block to avalanche
1.115 + h1 ^= ((unsigned int)h1) >> 16;
1.116 + h1 *= 0x85ebca6b;
1.117 + h1 ^= ((unsigned int)h1) >> 13;
1.118 + h1 *= 0xc2b2ae35;
1.119 + h1 ^= ((unsigned int)h1) >> 16;
1.120 +
1.121 + return h1;
1.122 +}
1.123 +
1.124 +// Murmur3 hashing for Strings
1.125 +jint AltHashing::murmur3_32(jint seed, const jchar* data, int len) {
1.126 + jint h1 = seed;
1.127 +
1.128 + int off = 0;
1.129 + int count = len;
1.130 +
1.131 + // body
1.132 + while (count >= 2) {
1.133 + jchar d1 = data[off++] & 0xFFFF;
1.134 + jchar d2 = data[off++];
1.135 + jint k1 = (d1 | d2 << 16);
1.136 +
1.137 + count -= 2;
1.138 +
1.139 + k1 *= 0xcc9e2d51;
1.140 + k1 = Integer_rotateLeft(k1, 15);
1.141 + k1 *= 0x1b873593;
1.142 +
1.143 + h1 ^= k1;
1.144 + h1 = Integer_rotateLeft(h1, 13);
1.145 + h1 = h1 * 5 + 0xe6546b64;
1.146 + }
1.147 +
1.148 + // tail
1.149 +
1.150 + if (count > 0) {
1.151 + int k1 = data[off];
1.152 +
1.153 + k1 *= 0xcc9e2d51;
1.154 + k1 = Integer_rotateLeft(k1, 15);
1.155 + k1 *= 0x1b873593;
1.156 + h1 ^= k1;
1.157 + }
1.158 +
1.159 + // finalization
1.160 + h1 ^= len * 2; // (Character.SIZE / Byte.SIZE);
1.161 +
1.162 + // finalization mix force all bits of a hash block to avalanche
1.163 + h1 ^= ((unsigned int)h1) >> 16;
1.164 + h1 *= 0x85ebca6b;
1.165 + h1 ^= ((unsigned int)h1) >> 13;
1.166 + h1 *= 0xc2b2ae35;
1.167 + h1 ^= ((unsigned int)h1) >> 16;
1.168 +
1.169 + return h1;
1.170 +}
1.171 +
1.172 +// Hash used for the seed.
1.173 +jint AltHashing::murmur3_32(jint seed, const int* data, int len) {
1.174 + jint h1 = seed;
1.175 +
1.176 + int off = 0;
1.177 + int end = len;
1.178 +
1.179 + // body
1.180 + while (off < end) {
1.181 + jint k1 = data[off++];
1.182 +
1.183 + k1 *= 0xcc9e2d51;
1.184 + k1 = Integer_rotateLeft(k1, 15);
1.185 + k1 *= 0x1b873593;
1.186 +
1.187 + h1 ^= k1;
1.188 + h1 = Integer_rotateLeft(h1, 13);
1.189 + h1 = h1 * 5 + 0xe6546b64;
1.190 + }
1.191 +
1.192 + // tail (always empty, as body is always 32-bit chunks)
1.193 +
1.194 + // finalization
1.195 +
1.196 + h1 ^= len * 4; // (Integer.SIZE / Byte.SIZE);
1.197 +
1.198 + // finalization mix force all bits of a hash block to avalanche
1.199 + h1 ^= ((juint)h1) >> 16;
1.200 + h1 *= 0x85ebca6b;
1.201 + h1 ^= ((juint)h1) >> 13;
1.202 + h1 *= 0xc2b2ae35;
1.203 + h1 ^= ((juint)h1) >> 16;
1.204 +
1.205 + return h1;
1.206 +}
1.207 +
1.208 +jint AltHashing::murmur3_32(const int* data, int len) {
1.209 + return murmur3_32(0, data, len);
1.210 +}
1.211 +
1.212 +#ifndef PRODUCT
1.213 +// Overloaded versions for internal test.
1.214 +jint AltHashing::murmur3_32(const jbyte* data, int len) {
1.215 + return murmur3_32(0, data, len);
1.216 +}
1.217 +
1.218 +jint AltHashing::murmur3_32(const jchar* data, int len) {
1.219 + return murmur3_32(0, data, len);
1.220 +}
1.221 +
1.222 +// Internal test for alternate hashing. Translated from JDK version
1.223 +// test/sun/misc/Hashing.java
1.224 +static const jbyte ONE_BYTE[] = { (jbyte) 0x80};
1.225 +static const jbyte TWO_BYTE[] = { (jbyte) 0x80, (jbyte) 0x81};
1.226 +static const jchar ONE_CHAR[] = { (jchar) 0x8180};
1.227 +static const jbyte THREE_BYTE[] = { (jbyte) 0x80, (jbyte) 0x81, (jbyte) 0x82};
1.228 +static const jbyte FOUR_BYTE[] = { (jbyte) 0x80, (jbyte) 0x81, (jbyte) 0x82, (jbyte) 0x83};
1.229 +static const jchar TWO_CHAR[] = { (jchar) 0x8180, (jchar) 0x8382};
1.230 +static const jint ONE_INT[] = { 0x83828180};
1.231 +static const jbyte SIX_BYTE[] = { (jbyte) 0x80, (jbyte) 0x81, (jbyte) 0x82, (jbyte) 0x83, (jbyte) 0x84, (jbyte) 0x85};
1.232 +static const jchar THREE_CHAR[] = { (jchar) 0x8180, (jchar) 0x8382, (jchar) 0x8584};
1.233 +static const jbyte EIGHT_BYTE[] = {
1.234 + (jbyte) 0x80, (jbyte) 0x81, (jbyte) 0x82,
1.235 + (jbyte) 0x83, (jbyte) 0x84, (jbyte) 0x85,
1.236 + (jbyte) 0x86, (jbyte) 0x87};
1.237 +static const jchar FOUR_CHAR[] = {
1.238 + (jchar) 0x8180, (jchar) 0x8382,
1.239 + (jchar) 0x8584, (jchar) 0x8786};
1.240 +
1.241 +static const jint TWO_INT[] = { 0x83828180, 0x87868584};
1.242 +
1.243 +static const juint MURMUR3_32_X86_CHECK_VALUE = 0xB0F57EE3;
1.244 +
1.245 +void AltHashing::testMurmur3_32_ByteArray() {
1.246 + // printf("testMurmur3_32_ByteArray\n");
1.247 +
1.248 + jbyte* vector = new jbyte[256];
1.249 + jbyte* hashes = new jbyte[4 * 256];
1.250 +
1.251 + for (int i = 0; i < 256; i++) {
1.252 + vector[i] = (jbyte) i;
1.253 + }
1.254 +
1.255 + // Hash subranges {}, {0}, {0,1}, {0,1,2}, ..., {0,...,255}
1.256 + for (int i = 0; i < 256; i++) {
1.257 + jint hash = murmur3_32(256 - i, vector, i);
1.258 + hashes[i * 4] = (jbyte) hash;
1.259 + hashes[i * 4 + 1] = (jbyte) (((juint)hash) >> 8);
1.260 + hashes[i * 4 + 2] = (jbyte) (((juint)hash) >> 16);
1.261 + hashes[i * 4 + 3] = (jbyte) (((juint)hash) >> 24);
1.262 + }
1.263 +
1.264 + // hash to get const result.
1.265 + juint final_hash = murmur3_32(hashes, 4*256);
1.266 +
1.267 + assert (MURMUR3_32_X86_CHECK_VALUE == final_hash,
1.268 + err_msg(
1.269 + "Calculated hash result not as expected. Expected %08X got %08X\n",
1.270 + MURMUR3_32_X86_CHECK_VALUE,
1.271 + final_hash));
1.272 +}
1.273 +
1.274 +void AltHashing::testEquivalentHashes() {
1.275 + jint jbytes, jchars, ints;
1.276 +
1.277 + // printf("testEquivalentHashes\n");
1.278 +
1.279 + jbytes = murmur3_32(TWO_BYTE, 2);
1.280 + jchars = murmur3_32(ONE_CHAR, 1);
1.281 + assert (jbytes == jchars,
1.282 + err_msg("Hashes did not match. b:%08x != c:%08x\n", jbytes, jchars));
1.283 +
1.284 + jbytes = murmur3_32(FOUR_BYTE, 4);
1.285 + jchars = murmur3_32(TWO_CHAR, 2);
1.286 + ints = murmur3_32(ONE_INT, 1);
1.287 + assert ((jbytes == jchars) && (jbytes == ints),
1.288 + err_msg("Hashes did not match. b:%08x != c:%08x != i:%08x\n", jbytes, jchars, ints));
1.289 +
1.290 + jbytes = murmur3_32(SIX_BYTE, 6);
1.291 + jchars = murmur3_32(THREE_CHAR, 3);
1.292 + assert (jbytes == jchars,
1.293 + err_msg("Hashes did not match. b:%08x != c:%08x\n", jbytes, jchars));
1.294 +
1.295 + jbytes = murmur3_32(EIGHT_BYTE, 8);
1.296 + jchars = murmur3_32(FOUR_CHAR, 4);
1.297 + ints = murmur3_32(TWO_INT, 2);
1.298 + assert ((jbytes == jchars) && (jbytes == ints),
1.299 + err_msg("Hashes did not match. b:%08x != c:%08x != i:%08x\n", jbytes, jchars, ints));
1.300 +}
1.301 +
1.302 +// Returns true if the alternate hashcode is correct
1.303 +void AltHashing::test_alt_hash() {
1.304 + testMurmur3_32_ByteArray();
1.305 + testEquivalentHashes();
1.306 +}
1.307 +#endif // PRODUCT
