RFR: JDK-8136893: Improve early java.lang.invoke infrastructure initialization
peter.levart at gmail.com
Fri Sep 25 15:19:02 UTC 2015
Thanks for looking into this.
On 09/25/2015 04:07 PM, Paul Sandoz wrote:
> This looks like a partial dup of https://bugs.openjdk.java.net/browse/JDK-8076596
Ah, sorry, I wasn't aware this has already been registered in JIRA. I
have linked the two issues together as DUPs.
> The changes look ok, but I am concerned post initialization there may be code paths taken that require the system class loader to be used but instead the boot stream class loader is used instead. Is that a legitimate concern?
It is legitimate, but I have inspected usages and:
- In java.lang.invoke.BoundMethodHandle.Factory#makeCbmhCtor, null is
passed explicitly and this method is used only from
java.lang.invoke.BoundMethodHandle.Factory#makeCtors which is used from
java.lang.Class<? extends java.lang.invoke.BoundMethodHandle>). These
usages only deal with erased MH types (Object, long, int, double, float).
- In java.lang.invoke.MemberName#getMethodType, the result of
MemberName.getClassLoader() is passed to the method. This is the class
loader of the member's declaring class. Any types referenced from the
member declaration should be resolvable from this class loader. A member
declared by a bootstrap class (MemberName.getClassLoader() returns null)
can only reference types resolvable from bootstrap loader.
- In java.lang.invoke.MemberName#getFieldType, the result of
MemberName.getClassLoader() is passed to the method. Similar applies as
- In java.lang.invoke.MethodHandleNatives#fixMethodType(Class<?>
callerClass, Object type), the callerClass.getClassLoader() is passed to
the method. This is invoked from:
Class<?> callerClass, int refKind,
Class<?> defc, String name, Object
which is called from
I suppose this is an upcall from VM to link a call to the
@PolymorphicSignature method and callerClass is the class in which the
invocation bytecodes are executed. Am I right? The reasoning is as
follows: if callerClass.getClassLoader() is sufficient for resolving
types that appear at the call site in a non-bootstrap callerClass, then
bootstrap classloader should be sufficient to resolve types that appear
at the call site in a bootstrap callerClass. Does anybody have any other
java.lang.ClassLoader) is only used from the newly introduced
> On 25 Sep 2015, at 15:37, Michael Haupt <michael.haupt at oracle.com> wrote:
>> Hi Peter,
>> thanks for this changeset. Note I'm not a Reviewer (with a capital R); please read this review in lower-case. ;-)
>> One question about MethodType: would you mind doing something about the naming of the newly introduced fromDescriptor() method? Its name does not suggest in any way that it chooses the class loader differently. The name is subtly different from that of fromDescriptorString(), and the signature is identical - it's probably really easy to confuse the two when working at the core libs level. Unfortunately, the only proposal for a name I can make, fromDescriptorStringBootCL(), is clunky. Maybe that's acceptable for a low-level method only visible at package level.
>>> Am 25.09.2015 um 08:46 schrieb Peter Levart <peter.levart at gmail.com>:
>>> I have run the tests in java.lang.invoke and only have a problem with 1 test which seems to be related to the test or jtreg itself and happens also without my patch applied:
>>> #Test Results (version 2)
>>> #Tue Sep 22 09:48:38 CEST 2015
>>> test result: Error. Parse Exception: `@library' must appear before first `@run'
>> Yes. The test is also marked as ignored until another issue is fixed, so that can be ignored.
>> Other than the above remark/suggestion, this looks fine. I'll defer to an upper-case Reviewer, though.
>> Dr. Michael Haupt | Principal Member of Technical Staff
>> Phone: +49 331 200 7277 | Fax: +49 331 200 7561
>> Oracle Java Platform Group | LangTools Team | Nashorn
>> Oracle Deutschland B.V. & Co. KG, Schiffbauergasse 14 | 14467 Potsdam, Germany
>> <http://www.oracle.com/commitment> Oracle is committed to developing practices and products that help protect the environment
More information about the core-libs-dev