RFR: 8080947: Add uint as a valid VM flag type (original) (raw)

David Holmes david.holmes at oracle.com
Wed Jun 3 09:43:36 UTC 2015

Hi David,

On 3/06/2015 6:51 PM, David Lindholm wrote:

Hi David,

Thanks for looking at this. I have a few places where I convert uint and int to Java types, besides management.cpp also whitebox.cpp/java and VM.java . After discussing with several people we though it was most correct to go with JLONG as java type for both int and uint, since it is not certain that an uint will fit in a JINT and I wanted the same java type for both int and uint. I don't think the C spec specifies the size of int (please correct me if I'm wrong), so having JLONG as type for int and uint is safer than JINT.

ILP32 programming model defines 32-bit int, long and pointer. LP64 programming model defines 64-bit long and 64-bit pointer, and so 32-bit int.

We already assume/require that an int is equivalent of a jint

./cpu/x86/vm/jni_x86.h: typedef int jint;

and the same for the other platforms. So int, uint, jint are all 32-bit.

However if you set a uint into a Java int you won't be able to read positive values >= 0x80000000, so using a jlong is necessary for that reason.

Sorry for the noise.

Cheers, David H.

But I can change to JINT if you think that is better.

Thanks, David On 2015-06-03 10:01, David Holmes wrote: Hi David,

On 28/05/2015 9:28 PM, David Lindholm wrote: Hi,

Please review this patch that adds uint and int as valid VM flag types. This patch adds the possibility to specify VM flags with types int and uint, it does not change the type of any flags.

Webrev: http://cr.openjdk.java.net/~david/JDK-8080947/webrev.hotspot.00/ Webrev: http://cr.openjdk.java.net/~david/JDK-8080947/webrev.jdk.00/ Bug: https://bugs.openjdk.java.net/browse/JDK-8080947 src/share/vm/services/management.cpp + } else if (flag->isint()) { + global->value.j = (jlong)flag->getint(); + global->type = JMMVMGLOBALTYPEJLONG; + } else if (flag->isuint()) { + global->value.j = (jlong)flag->getuint(); + global->type = JMMVMGLOBALTYPEJLONG; These should be JINT types not JLONG. Cheers, David H. ------- Testing: Passed JPRT Thanks, David

More information about the hotspot-dev mailing list