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

src/share/vm/classfile/altHashing.cpp

 /*
- * 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 @@ intptr_t object_hash(Klass* k) {
 }
 
 // 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 @@ jint AltHashing::compute_seed() {
 
 
 // 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 @@ jint AltHashing::murmur3_32(jint seed, const jbyte* data, int len) {
   // tail
 
   if (count > 0) {
-    jint k1 = 0;
+    juint k1 = 0;
 
     switch (count) {
       case 3:
@@ -109,18 +109,18 @@ jint AltHashing::murmur3_32(jint seed, const jbyte* data, int len) {
   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 @@ jint AltHashing::murmur3_32(jint seed, const jchar* data, int len) {
   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 @@ jint AltHashing::murmur3_32(jint seed, const jchar* data, int len) {
   // tail
 
   if (count > 0) {
-    int k1 = data[off];
+    juint k1 = (juint)data[off];
 
     k1 *= 0xcc9e2d51;
     k1 = Integer_rotateLeft(k1, 15);
@@ -157,25 +157,25 @@ jint AltHashing::murmur3_32(jint seed, const jchar* data, int len) {
   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 @@ jint AltHashing::murmur3_32(jint seed, const int* data, int len) {
   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 @@ void AltHashing::testMurmur3_32_ByteArray() {
 
   // 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::testMurmur3_32_ByteArray() {
 }
 
 void AltHashing::testEquivalentHashes() {
-  jint jbytes, jchars, ints;
+  juint jbytes, jchars, ints;
 
   // printf("testEquivalentHashes\n");
 

src/share/vm/classfile/altHashing.hpp

 /*
- * Copyright (c) 2012, 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
@@ -39,24 +39,24 @@
 class AltHashing : AllStatic {
 
   // utility function copied from java/lang/Integer
-  static jint Integer_rotateLeft(jint i, int distance) {
-    return (i << distance) | (((juint)i) >> (32-distance));
+  static juint Integer_rotateLeft(juint i, int distance) {
+    return (i << distance) | (i >> (32-distance));
   }
-  static jint murmur3_32(const int* data, int len);
-  static jint murmur3_32(jint seed, const int* data, int len);
+  static juint murmur3_32(const int* data, int len);
+  static juint murmur3_32(juint seed, const int* data, int len);
 
 #ifndef PRODUCT
   // Hashing functions used for internal testing
-  static jint murmur3_32(const jbyte* data, int len);
-  static jint murmur3_32(const jchar* data, int len);
+  static juint murmur3_32(const jbyte* data, int len);
+  static juint murmur3_32(const jchar* data, int len);
   static void testMurmur3_32_ByteArray();
   static void testEquivalentHashes();
 #endif // PRODUCT
 
  public:
-  static jint compute_seed();
-  static jint murmur3_32(jint seed, const jbyte* data, int len);
-  static jint murmur3_32(jint seed, const jchar* data, int len);
+  static juint compute_seed();
+  static juint murmur3_32(juint seed, const jbyte* data, int len);
+  static juint murmur3_32(juint seed, const jchar* data, int len);
   NOT_PRODUCT(static void test_alt_hash();)
 };
 #endif // SHARE_VM_CLASSFILE_ALTHASHING_HPP

src/share/vm/oops/instanceKlass.hpp

 /*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -554,6 +554,7 @@ class InstanceKlass: public Klass {
     if (hk == NULL) {
       return NULL;
     } else {
+      assert(*hk != NULL, "host klass should always be set if the address is not null");
       return *hk;
     }
   }

src/share/vm/oops/metadata.hpp

 /*
- * Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 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
@@ -40,7 +40,7 @@ class Metadata : public MetaspaceObj {
   int identity_hash()                { return (int)(uintptr_t)this; }
 
   // Rehashing support for tables containing pointers to this
-  unsigned int new_hash(jint seed)   { ShouldNotReachHere();  return 0; }
+  unsigned int new_hash(juint seed)   { ShouldNotReachHere();  return 0; }
 
   virtual bool is_klass()              const volatile { return false; }
   virtual bool is_method()             const volatile { return false; }

src/share/vm/oops/oop.cpp

 /*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -102,7 +102,7 @@ intptr_t oopDesc::slow_identity_hash() {
 }
 
 // When String table needs to rehash
-unsigned int oopDesc::new_hash(jint seed) {
+unsigned int oopDesc::new_hash(juint seed) {
   EXCEPTION_MARK;
   ResourceMark rm;
   int length;

src/share/vm/oops/oop.hpp

 /*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -362,7 +362,7 @@ class oopDesc {
   intptr_t slow_identity_hash();
 
   // Alternate hashing code if string table is rehashed
-  unsigned int new_hash(jint seed);
+  unsigned int new_hash(juint seed);
 
   // marks are forwarded to stack when object is locked
   bool     has_displaced_mark() const;

src/share/vm/oops/symbol.cpp

 /*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -207,7 +207,7 @@ const char* Symbol::as_klass_external_name() const {
 }
 
 // Alternate hashing for unbalanced symbol tables.
-unsigned int Symbol::new_hash(jint seed) {
+unsigned int Symbol::new_hash(juint seed) {
   ResourceMark rm;
   // Use alternate hashing algorithm on this symbol.
   return AltHashing::murmur3_32(seed, (const jbyte*)as_C_string(), utf8_length());

src/share/vm/oops/symbol.hpp

 /*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -154,7 +154,7 @@ class Symbol : private SymbolBase {
   int identity_hash()       { return _identity_hash; }
 
   // For symbol table alternate hashing
-  unsigned int new_hash(jint seed);
+  unsigned int new_hash(juint seed);
 
   // Reference counting.  See comments above this class for when to use.
   int refcount() const      { return _refcount; }

src/share/vm/utilities/hashtable.cpp

 /*
- * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 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
@@ -93,7 +93,7 @@ template <MEMFLAGS F> bool BasicHashtable<F>::check_rehash_table(int count) {
   return false;
 }
 
-template <class T, MEMFLAGS F> jint Hashtable<T, F>::_seed = 0;
+template <class T, MEMFLAGS F> juint Hashtable<T, F>::_seed = 0;
 
 // Create a new table and using alternate hash code, populate the new table
 // with the existing elements.   This can be used to change the hash code

src/share/vm/utilities/hashtable.hpp

 /*
- * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 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
@@ -280,7 +280,7 @@ protected:
   // Function to move these elements into the new table.
   void move_to(Hashtable<T, F>* new_table);
   static bool use_alternate_hashcode()  { return _seed != 0; }
-  static jint seed()                    { return _seed; }
+  static juint seed()                    { return _seed; }
 
   static int literal_size(Symbol *symbol);
   static int literal_size(oop oop);
@@ -296,7 +296,7 @@ public:
   void dump_table(outputStream* st, const char *table_name);
 
  private:
-  static jint _seed;
+  static juint _seed;
 };