jdk8-mips64-public/hotspot: src/share/vm/classfile/altHashing.cpp@710a3c8b516e (annotated)

src/share/vm/classfile/altHashing.cpp@710a3c8b516e (annotated)

src/share/vm/classfile/altHashing.cpp

Tue, 08 Aug 2017 15:57:29 +0800

author: aoqi
date: Tue, 08 Aug 2017 15:57:29 +0800
changeset 6876: 710a3c8b516e
parent 6351: f9e35a9dc8c7
parent 0: f90c822e73f8
child 9448: 73d689add964
permissions: -rw-r--r--

merge

 /*
  * Copyright (c) 2012, 2014, 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/symbolTable.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "oops/markOop.hpp"
 #include "runtime/thread.hpp"
 // Get the hash code of the classes mirror if it exists, otherwise just
 // return a random number, which is one of the possible hash code used for
 // objects.  We don't want to call the synchronizer hash code to install
 // this value because it may safepoint.
 intptr_t object_hash(Klass* k) {
   intptr_t hc = k->java_mirror()->mark()->hash();
   return hc != markOopDesc::no_hash ? hc : os::random();
 }
 // Seed value used for each alternative hash calculated.
 juint AltHashing::compute_seed() {
   jlong nanos = os::javaTimeNanos();
   jlong now = os::javaTimeMillis();
   int SEED_MATERIAL[8] = {
             (int) object_hash(SystemDictionary::String_klass()),
             (int) object_hash(SystemDictionary::System_klass()),
             (int) os::random(),  // current thread isn't a java thread
             (int) (((julong)nanos) >> 32),
             (int) nanos,
             (int) (((julong)now) >> 32),
             (int) now,
             (int) (os::javaTimeNanos() >> 2)
   };
   return murmur3_32(SEED_MATERIAL, 8);
 }
 // Murmur3 hashing for Symbol
 juint AltHashing::murmur3_32(juint seed, const jbyte* data, int len) {
   juint h1 = seed;
   int count = len;
   int offset = 0;
   // body
   while (count >= 4) {
     juint k1 = (data[offset] & 0x0FF)
         | (data[offset + 1] & 0x0FF) << 8
         | (data[offset + 2] & 0x0FF) << 16
         | data[offset + 3] << 24;
     count -= 4;
     offset += 4;
     k1 *= 0xcc9e2d51;
     k1 = Integer_rotateLeft(k1, 15);
     k1 *= 0x1b873593;
     h1 ^= k1;
     h1 = Integer_rotateLeft(h1, 13);
     h1 = h1 * 5 + 0xe6546b64;
   }
   // tail
   if (count > 0) {
     juint k1 = 0;
     switch (count) {
       case 3:
         k1 ^= (data[offset + 2] & 0xff) << 16;
       // fall through
       case 2:
         k1 ^= (data[offset + 1] & 0xff) << 8;
       // fall through
       case 1:
         k1 ^= (data[offset] & 0xff);
       // fall through
       default:
         k1 *= 0xcc9e2d51;
         k1 = Integer_rotateLeft(k1, 15);
         k1 *= 0x1b873593;
         h1 ^= k1;
     }
   }
   // finalization
   h1 ^= len;
   // finalization mix force all bits of a hash block to avalanche
   h1 ^= h1 >> 16;
   h1 *= 0x85ebca6b;
   h1 ^= h1 >> 13;
   h1 *= 0xc2b2ae35;
   h1 ^= h1 >> 16;
   return h1;
 }
 // Murmur3 hashing for Strings
 juint AltHashing::murmur3_32(juint seed, const jchar* data, int len) {
   juint h1 = seed;
   int off = 0;
   int count = len;
   // body
   while (count >= 2) {
     jchar d1 = data[off++] & 0xFFFF;
     jchar d2 = data[off++];
     juint k1 = (d1 | d2 << 16);
     count -= 2;
     k1 *= 0xcc9e2d51;
     k1 = Integer_rotateLeft(k1, 15);
     k1 *= 0x1b873593;
     h1 ^= k1;
     h1 = Integer_rotateLeft(h1, 13);
     h1 = h1 * 5 + 0xe6546b64;
   }
   // tail
   if (count > 0) {
     juint k1 = (juint)data[off];
     k1 *= 0xcc9e2d51;
     k1 = Integer_rotateLeft(k1, 15);
     k1 *= 0x1b873593;
     h1 ^= k1;
   }
   // finalization
   h1 ^= len * 2; // (Character.SIZE / Byte.SIZE);
   // finalization mix force all bits of a hash block to avalanche
   h1 ^= h1 >> 16;
   h1 *= 0x85ebca6b;
   h1 ^= h1 >> 13;
   h1 *= 0xc2b2ae35;
   h1 ^= h1 >> 16;
   return h1;
 }
 // Hash used for the seed.
 juint AltHashing::murmur3_32(juint seed, const int* data, int len) {
   juint h1 = seed;
   int off = 0;
   int end = len;
   // body
   while (off < end) {
     juint k1 = (juint)data[off++];
     k1 *= 0xcc9e2d51;
     k1 = Integer_rotateLeft(k1, 15);
     k1 *= 0x1b873593;
     h1 ^= k1;
     h1 = Integer_rotateLeft(h1, 13);
     h1 = h1 * 5 + 0xe6546b64;
   }
   // tail (always empty, as body is always 32-bit chunks)
   // finalization
   h1 ^= len * 4; // (Integer.SIZE / Byte.SIZE);
   // finalization mix force all bits of a hash block to avalanche
   h1 ^= h1 >> 16;
   h1 *= 0x85ebca6b;
   h1 ^= h1 >> 13;
   h1 *= 0xc2b2ae35;
   h1 ^= h1 >> 16;
   return h1;
 }
 juint AltHashing::murmur3_32(const int* data, int len) {
   return murmur3_32(0, data, len);
 }
 #ifndef PRODUCT
 // Overloaded versions for internal test.
 juint AltHashing::murmur3_32(const jbyte* data, int len) {
   return murmur3_32(0, data, len);
 }
 juint AltHashing::murmur3_32(const jchar* data, int len) {
   return murmur3_32(0, data, len);
 }
 // Internal test for alternate hashing.  Translated from JDK version
 // test/sun/misc/Hashing.java
 static const jbyte ONE_BYTE[] = { (jbyte) 0x80};
 static const jbyte TWO_BYTE[] = { (jbyte) 0x80, (jbyte) 0x81};
 static const jchar ONE_CHAR[] = { (jchar) 0x8180};
 static const jbyte THREE_BYTE[] = { (jbyte) 0x80, (jbyte) 0x81, (jbyte) 0x82};
 static const jbyte FOUR_BYTE[] = { (jbyte) 0x80, (jbyte) 0x81, (jbyte) 0x82, (jbyte) 0x83};
 static const jchar TWO_CHAR[] = { (jchar) 0x8180, (jchar) 0x8382};
 static const jint ONE_INT[] = { 0x83828180};
 static const jbyte SIX_BYTE[] = { (jbyte) 0x80, (jbyte) 0x81, (jbyte) 0x82, (jbyte) 0x83, (jbyte) 0x84, (jbyte) 0x85};
 static const jchar THREE_CHAR[] = { (jchar) 0x8180, (jchar) 0x8382, (jchar) 0x8584};
 static const jbyte EIGHT_BYTE[] = {
   (jbyte) 0x80, (jbyte) 0x81, (jbyte) 0x82,
   (jbyte) 0x83, (jbyte) 0x84, (jbyte) 0x85,
   (jbyte) 0x86, (jbyte) 0x87};
 static const jchar FOUR_CHAR[] = {
   (jchar) 0x8180, (jchar) 0x8382,
   (jchar) 0x8584, (jchar) 0x8786};
 static const jint TWO_INT[] = { 0x83828180, 0x87868584};
 static const juint MURMUR3_32_X86_CHECK_VALUE = 0xB0F57EE3;
 void AltHashing::testMurmur3_32_ByteArray() {
   // printf("testMurmur3_32_ByteArray\n");
   jbyte vector[256];
   jbyte hashes[4 * 256];
   for (int i = 0; i < 256; i++) {
     vector[i] = (jbyte) i;
   }
   // Hash subranges {}, {0}, {0,1}, {0,1,2}, ..., {0,...,255}
   for (int i = 0; i < 256; i++) {
     juint hash = murmur3_32(256 - i, vector, i);
     hashes[i * 4] = (jbyte) hash;
     hashes[i * 4 + 1] = (jbyte)(hash >> 8);
     hashes[i * 4 + 2] = (jbyte)(hash >> 16);
     hashes[i * 4 + 3] = (jbyte)(hash >> 24);
   }
   // hash to get const result.
   juint final_hash = murmur3_32(hashes, 4*256);
   assert (MURMUR3_32_X86_CHECK_VALUE == final_hash,
     err_msg(
         "Calculated hash result not as expected. Expected %08X got %08X\n",
         MURMUR3_32_X86_CHECK_VALUE,
         final_hash));
 }
 void AltHashing::testEquivalentHashes() {
   juint jbytes, jchars, ints;
   // printf("testEquivalentHashes\n");
   jbytes = murmur3_32(TWO_BYTE, 2);
   jchars = murmur3_32(ONE_CHAR, 1);
   assert (jbytes == jchars,
     err_msg("Hashes did not match. b:%08x != c:%08x\n", jbytes, jchars));
   jbytes = murmur3_32(FOUR_BYTE, 4);
   jchars = murmur3_32(TWO_CHAR, 2);
   ints = murmur3_32(ONE_INT, 1);
   assert ((jbytes == jchars) && (jbytes == ints),
     err_msg("Hashes did not match. b:%08x != c:%08x != i:%08x\n", jbytes, jchars, ints));
   jbytes = murmur3_32(SIX_BYTE, 6);
   jchars = murmur3_32(THREE_CHAR, 3);
   assert (jbytes == jchars,
     err_msg("Hashes did not match. b:%08x != c:%08x\n", jbytes, jchars));
   jbytes = murmur3_32(EIGHT_BYTE, 8);
   jchars = murmur3_32(FOUR_CHAR, 4);
   ints = murmur3_32(TWO_INT, 2);
   assert ((jbytes == jchars) && (jbytes == ints),
     err_msg("Hashes did not match. b:%08x != c:%08x != i:%08x\n", jbytes, jchars, ints));
 }
 // Returns true if the alternate hashcode is correct
 void AltHashing::test_alt_hash() {
   testMurmur3_32_ByteArray();
   testEquivalentHashes();
 }
 #endif // PRODUCT

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/classfile/altHashing.cpp@710a3c8b516e (annotated)

src/share/vm/classfile/altHashing.cpp