Mercurial > hg > graal-compiler
diff src/share/vm/classfile/altHashing.cpp @ 14340:cd6b3f1a94ff
8033792: AltHashing used jint for imprecise bit shifting
Summary: AltHashing used jint the way of juint in bit shifting which could lead loss of precision. Fix by change _seed defined as juint.
Reviewed-by: coleenp, ccheung
Contributed-by: yumin.qi@oracle.com
author | minqi |
---|---|
date | Mon, 10 Feb 2014 21:29:14 -0800 |
parents | f9be75d21404 |
children | 4ca6dc0799b6 |
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--- a/src/share/vm/classfile/altHashing.cpp Mon Feb 10 14:07:11 2014 -0800 +++ b/src/share/vm/classfile/altHashing.cpp Mon Feb 10 21:29:14 2014 -0800 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. + * 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 @@ -39,18 +39,18 @@ } // Seed value used for each alternative hash calculated. -jint AltHashing::compute_seed() { +juint AltHashing::compute_seed() { jlong nanos = os::javaTimeNanos(); jlong now = os::javaTimeMillis(); - jint SEED_MATERIAL[8] = { - (jint) object_hash(SystemDictionary::String_klass()), - (jint) object_hash(SystemDictionary::System_klass()), - (jint) os::random(), // current thread isn't a java thread - (jint) (((julong)nanos) >> 32), - (jint) nanos, - (jint) (((julong)now) >> 32), - (jint) now, - (jint) (os::javaTimeNanos() >> 2) + 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); @@ -58,14 +58,14 @@ // Murmur3 hashing for Symbol -jint AltHashing::murmur3_32(jint seed, const jbyte* data, int len) { - jint h1 = seed; +juint AltHashing::murmur3_32(juint seed, const jbyte* data, int len) { + juint h1 = seed; int count = len; int offset = 0; // body while (count >= 4) { - jint k1 = (data[offset] & 0x0FF) + juint k1 = (data[offset] & 0x0FF) | (data[offset + 1] & 0x0FF) << 8 | (data[offset + 2] & 0x0FF) << 16 | data[offset + 3] << 24; @@ -85,7 +85,7 @@ // tail if (count > 0) { - jint k1 = 0; + juint k1 = 0; switch (count) { case 3: @@ -109,18 +109,18 @@ h1 ^= len; // finalization mix force all bits of a hash block to avalanche - h1 ^= ((unsigned int)h1) >> 16; + h1 ^= h1 >> 16; h1 *= 0x85ebca6b; - h1 ^= ((unsigned int)h1) >> 13; + h1 ^= h1 >> 13; h1 *= 0xc2b2ae35; - h1 ^= ((unsigned int)h1) >> 16; + h1 ^= h1 >> 16; return h1; } // Murmur3 hashing for Strings -jint AltHashing::murmur3_32(jint seed, const jchar* data, int len) { - jint h1 = seed; +juint AltHashing::murmur3_32(juint seed, const jchar* data, int len) { + juint h1 = seed; int off = 0; int count = len; @@ -129,7 +129,7 @@ while (count >= 2) { jchar d1 = data[off++] & 0xFFFF; jchar d2 = data[off++]; - jint k1 = (d1 | d2 << 16); + juint k1 = (d1 | d2 << 16); count -= 2; @@ -145,7 +145,7 @@ // tail if (count > 0) { - int k1 = data[off]; + juint k1 = (juint)data[off]; k1 *= 0xcc9e2d51; k1 = Integer_rotateLeft(k1, 15); @@ -157,25 +157,25 @@ h1 ^= len * 2; // (Character.SIZE / Byte.SIZE); // finalization mix force all bits of a hash block to avalanche - h1 ^= ((unsigned int)h1) >> 16; + h1 ^= h1 >> 16; h1 *= 0x85ebca6b; - h1 ^= ((unsigned int)h1) >> 13; + h1 ^= h1 >> 13; h1 *= 0xc2b2ae35; - h1 ^= ((unsigned int)h1) >> 16; + h1 ^= h1 >> 16; return h1; } // Hash used for the seed. -jint AltHashing::murmur3_32(jint seed, const int* data, int len) { - jint h1 = 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) { - jint k1 = data[off++]; + juint k1 = (juint)data[off++]; k1 *= 0xcc9e2d51; k1 = Integer_rotateLeft(k1, 15); @@ -193,26 +193,26 @@ h1 ^= len * 4; // (Integer.SIZE / Byte.SIZE); // finalization mix force all bits of a hash block to avalanche - h1 ^= ((juint)h1) >> 16; + h1 ^= h1 >> 16; h1 *= 0x85ebca6b; - h1 ^= ((juint)h1) >> 13; + h1 ^= h1 >> 13; h1 *= 0xc2b2ae35; - h1 ^= ((juint)h1) >> 16; + h1 ^= h1 >> 16; return h1; } -jint AltHashing::murmur3_32(const int* data, int len) { +juint AltHashing::murmur3_32(const int* data, int len) { return murmur3_32(0, data, len); } #ifndef PRODUCT // Overloaded versions for internal test. -jint AltHashing::murmur3_32(const jbyte* data, int len) { +juint AltHashing::murmur3_32(const jbyte* data, int len) { return murmur3_32(0, data, len); } -jint AltHashing::murmur3_32(const jchar* data, int len) { +juint AltHashing::murmur3_32(const jchar* data, int len) { return murmur3_32(0, data, len); } @@ -251,11 +251,11 @@ // Hash subranges {}, {0}, {0,1}, {0,1,2}, ..., {0,...,255} for (int i = 0; i < 256; i++) { - jint hash = murmur3_32(256 - i, vector, i); + juint hash = murmur3_32(256 - i, vector, i); hashes[i * 4] = (jbyte) hash; - hashes[i * 4 + 1] = (jbyte) (((juint)hash) >> 8); - hashes[i * 4 + 2] = (jbyte) (((juint)hash) >> 16); - hashes[i * 4 + 3] = (jbyte) (((juint)hash) >> 24); + 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. @@ -269,7 +269,7 @@ } void AltHashing::testEquivalentHashes() { - jint jbytes, jchars, ints; + juint jbytes, jchars, ints; // printf("testEquivalentHashes\n");