void G1StringDedupTable::deduplicate(oop java_string, G1StringDedupStat& stat) {
assert(java_lang_String::is_instance(java_string), "Must be a string");
NoSafepointVerifier nsv;
stat.inc_inspected();
typeArrayOop value = java_lang_String::value(java_string);
if (value == NULL) {
// String has no value
stat.inc_skipped();
return;
}
bool latin1 = java_lang_String::is_latin1(java_string);
unsigned int hash = 0;
if (use_java_hash()) {
// Get hash code from cache
hash = java_lang_String::hash(java_string);
}
if (hash == 0) {
// Compute hash
hash = hash_code(value, latin1);
stat.inc_hashed();
if (use_java_hash() && hash != 0) {
// Store hash code in cache
java_lang_String::set_hash(java_string, hash);
}
}
typeArrayOop existing_value = lookup_or_add(value, latin1, hash);
if (existing_value == value) {
// Same value, already known
stat.inc_known();
return;
}
// Get size of value array
uintx size_in_bytes = value->size() * HeapWordSize;
stat.inc_new(size_in_bytes);
if (existing_value != NULL) {
// Enqueue the reference to make sure it is kept alive. Concurrent mark might
// otherwise declare it dead if there are no other strong references to this object.
G1SATBCardTableModRefBS::enqueue(existing_value);
// Existing value found, deduplicate string
java_lang_String::set_value(java_string, existing_value);
if (G1CollectedHeap::heap()->is_in_young(value)) {
stat.inc_deduped_young(size_in_bytes);
} else {
stat.inc_deduped_old(size_in_bytes);
}
}
}
unsigned int G1StringDedupTable::hash_code(typeArrayOop value, bool latin1) {
unsigned int hash;
int length = value->length();
if (latin1) {
const jbyte* data = (jbyte*)value->base(T_BYTE);
if (use_java_hash()) {
hash = java_lang_String::hash_code(data, length);
} else {
hash = AltHashing::murmur3_32(_table->_hash_seed, data, length);
}
} else {
length /= sizeof(jchar) / sizeof(jbyte); // Convert number of bytes to number of chars
const jchar* data = (jchar*)value->base(T_CHAR);
if (use_java_hash()) {
hash = java_lang_String::hash_code(data, length);
} else {
hash = AltHashing::murmur3_32(_table->_hash_seed, data, length);
}
}
return hash;
}
unsigned int G1StringDedupTable::hash_code(typeArrayOop value) {
unsigned int hash;
int length = value->length();
const jchar* data = (jchar*)value->base(T_CHAR);
if (use_java_hash()) {
hash = java_lang_String::hash_code(data, length);
} else {
hash = AltHashing::murmur3_32(_table->_hash_seed, data, length);
}
return hash;
}
