Examples with J9IdentityHashDataPointer com.ibm.j9ddr.vm29.pointer.generated.J9IdentityHashDataPointer used on opensource projects

Example 1 with J9IdentityHashDataPointer

use of com.ibm.j9ddr.vm29.pointer.generated.J9IdentityHashDataPointer in project openj9 by eclipse.

the class ObjectHash method getSalt.

private static U32 getSalt(J9JavaVMPointer vm, UDATA objectPointer) throws CorruptDataException {
    /* set up the default salt */
    U32 salt = (new U32(1421595292)).bitXor(new U32(UDATA.cast(vm)));
    J9IdentityHashDataPointer hashData = vm.identityHashData();
    UDATA saltPolicy = hashData.hashSaltPolicy();
    /* Replacing case statement in C with an if-else if statements since case expressions must use constant */
    if (saltPolicy.eq(J9IdentityHashData.J9_IDENTITY_HASH_SALT_POLICY_STANDARD)) {
        /* Gencon/optavgpause/optthruput use the default salt for non heap and
			 * tenure space but they use a table salt for the nursery.
			 *
			 * hashData->hashData1 is nursery base
			 * hashData->hashData2 is nursery top
			 */
        if (objectPointer.gte(hashData.hashData1())) {
            if (objectPointer.lt(hashData.hashData2())) {
                /* Object is in the nursery */
                salt = hashData.hashSaltTableEA().at(0);
            } else {
            /* not in the heap so use default salt */
            }
        } else {
        /* not in the nursery so use default salt */
        }
    } else if (saltPolicy.eq(J9IdentityHashData.J9_IDENTITY_HASH_SALT_POLICY_REGION)) {
        if (objectPointer.gte(hashData.hashData1())) {
            if (objectPointer.lt(hashData.hashData2())) {
                UDATA heapDelta = objectPointer.sub(hashData.hashData1());
                UDATA index = heapDelta.rightShift(hashData.hashData3());
                salt = hashData.hashSaltTableEA().at(index);
            } else {
            /* not in the heap so use default salt */
            }
        } else {
        /* not in the heap so use default salt */
        }
    } else if (saltPolicy.eq(J9IdentityHashData.J9_IDENTITY_HASH_SALT_POLICY_NONE)) {
    /* Use default salt */
    } else {
        /* Unrecognized salt policy.  Should assert but we are in util */
        throw new CorruptDataException("Invalid salt policy");
    }
    return salt;
}