RFR (S) 8210842: Handle JNIGlobalRefLocker.cpp
Martin Buchholz
martinrb at google.com
Fri Sep 28 01:23:30 UTC 2018
Some of us have lobbied to make openjdk source C++11, but it's not yet.
If you're brave, you can try to change that flag to -std=gnu++11
On Thu, Sep 27, 2018 at 2:33 PM, JC Beyler <jcbeyler at google.com> wrote:
> Hi all,
>
> Sorry to come back to this so late in the game, but somehow when I synced my
> hg clone (or the issue was always there and it is a flaky build), it seems
> that something in the build might have changed? Basically now it seems that
> the build is adding flags that makes my usage of unique_ptr fail.
>
> I "think" it is due to the build adding the gnu++98 standard (But this has
> been there for a while it seems so most likely a side-effect is it is being
> now used):
>
> CXXSTD_CXXFLAG="-std=gnu++98"
> FLAGS_CXX_COMPILER_CHECK_ARGUMENTS(ARGUMENT: [$CXXSTD_CXXFLAG -Werror],
> IF_FALSE: [CXXSTD_CXXFLAG=""])
>
> (from:
> https://hg.openjdk.java.net/jdk/jdk/file/dade6dd87bb4/make/autoconf/flags-cflags.m4)
> but I'm not sure.
>
> When I remove that flag, my g++ goes to a more recent standard and
> unique_ptr works.
>
> So I now have to ask you all:
> 1) Should we try to fix the build system to at least have C++11 for the
> C++ tests, then my webrev.04 can stay as is but has to wait for that to
> happen
> 2) Should we push a new version that does not use unique_ptr? That
> solution would look like the following webrev:
> http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.05/
>
> Sorry for the last minute rug pull,
> Jc
>
> On Thu, Sep 27, 2018 at 11:32 AM Mikael Vidstedt
> <mikael.vidstedt at oracle.com> wrote:
>>
>>
>> Very, very nice! Thanks for adding the comment and renaming the class!
>> Ship it!
>>
>> Cheers,
>> Mikael
>>
>>
>> On Sep 27, 2018, at 10:45 AM, JC Beyler <jcbeyler at google.com> wrote:
>>
>> Hi Mikael and David,
>>
>> @David: I thought it was implicit but did not want to presume on this one
>> because my goal is to start propagating this new class in the test base and
>> get the checks to be done implicitly so I was probably being over-cautious
>> @Mikael: done and done, what do you think of the comment here :
>> http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.04/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.hpp.html
>>
>> For all, the new webrev is here:
>> Webrev: http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.04/
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8210842
>>
>> Thanks,
>> Jc
>>
>> On Thu, Sep 27, 2018 at 6:03 AM David Holmes <david.holmes at oracle.com>
>> wrote:
>>>
>>> Sorry Jc, I thought my LGTM was implicit. :)
>>>
>>> Thanks,
>>> David
>>>
>>> On 26/09/2018 11:52 PM, JC Beyler wrote:
>>> > Ping on this, anybody have time to do a review and give a LGTM? Or
>>> > David
>>> > if you have time and will to provide an explicit LGTM :)
>>> >
>>> > Thanks,
>>> > Jc
>>> >
>>> > On Mon, Sep 24, 2018 at 9:18 AM JC Beyler <jcbeyler at google.com
>>> > <mailto:jcbeyler at google.com>> wrote:
>>> >
>>> > Hi David,
>>> >
>>> > Sounds good to me, Alex gave me one LGTM, so it seems I'm waiting
>>> > for an explicit LGTM from you or from someone else on this list to
>>> > do a review.
>>> >
>>> > Thanks again for your help,
>>> > Jc
>>> >
>>> > On Sun, Sep 23, 2018 at 9:22 AM David Holmes
>>> > <david.holmes at oracle.com <mailto:david.holmes at oracle.com>> wrote:
>>> >
>>> > Hi Jc,
>>> >
>>> > I don't think it is an issue for this to go ahead. If the
>>> > static
>>> > analysis tool has an issue then we can either find out how to
>>> > teach it
>>> > about this code structure, or else flag the issues as false
>>> > positives.
>>> > I'd be relying on one of the serviceability team here to handle
>>> > that if
>>> > the problem arises.
>>> >
>>> > Thanks,
>>> > David
>>> >
>>> > On 23/09/2018 12:17 PM, JC Beyler wrote:
>>> > > Hi David,
>>> > >
>>> > > No worries with the time to answer; I appreciate the review!
>>> > >
>>> > > That's a fair point. Is it possible to "describe" to the
>>> > static analysis
>>> > > tool to "trust" calls made in the SafeJNIEnv class?
>>> > >
>>> > > Otherwise, do you have any idea on how to go forward? For
>>> > what it's
>>> > > worth, this current webrev does not try to replace exception
>>> > checking
>>> > > with the SafeJNIEnv (it actually adds it), so for now the
>>> > > question/solution could be delayed. I could continue working
>>> > on this in
>>> > > the scope of both the nsk/gc/lock/jniref code base and the
>>> > NSK_VERIFIER
>>> > > macro removal and we can look at how to tackle the cases
>>> > where the tests
>>> > > are actually calling exception checking (I know my
>>> > heapmonitor does for
>>> > > example).
>>> > >
>>> > > Let me know what you think and thanks for the review,
>>> > > Jc
>>> > >
>>> > >
>>> > > On Sun, Sep 23, 2018 at 6:48 AM David Holmes
>>> > <david.holmes at oracle.com <mailto:david.holmes at oracle.com>
>>> > > <mailto:david.holmes at oracle.com
>>> > <mailto:david.holmes at oracle.com>>> wrote:
>>> > >
>>> > > Hi Jc,
>>> > >
>>> > > Sorry for the delay on getting back to this but I'm
>>> > travelling at the
>>> > > moment.
>>> > >
>>> > > This looks quite neat. Thanks also to Alex for all the
>>> > suggestions.
>>> > >
>>> > > My only remaining concern is that static analysis tools
>>> > may not like
>>> > > this because they may not be able to determine that we
>>> > won't make
>>> > > subsequent JNI calls when an exception happens in the
>>> > first. That's not
>>> > > a reason not to do this of course, just flagging that we
>>> > may have to do
>>> > > something to deal with that problem.
>>> > >
>>> > > Thanks,
>>> > > David
>>> > >
>>> > > On 20/09/2018 11:56 AM, JC Beyler wrote:
>>> > > > Hi Alex,
>>> > > >
>>> > > > Done here, thanks for the review:
>>> > > >
>>> > > > Webrev:
>>> > http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.03/
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.03/>
>>> > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.03/>
>>> > > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.03/>
>>> > > > Bug: https://bugs.openjdk.java.net/browse/JDK-8210842
>>> > > >
>>> > > > Thanks again!
>>> > > > Jc
>>> > > >
>>> > > >
>>> > > > On Wed, Sep 19, 2018 at 5:13 PM Alex Menkov
>>> > > <alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>
>>> > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>>
>>> > > > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>
>>> > > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>>>> wrote:
>>> > > >
>>> > > > Hi Jc,
>>> > > >
>>> > > > Looks good to me.
>>> > > > A minor note:
>>> > > > - I'd move ErrorHandler typedef to SafeJNIEnv
>>> > class to avoid
>>> > > global
>>> > > > namespece pollution (ErrorHandler is too generic
>>> > name).
>>> > > >
>>> > > > --alex
>>> > > >
>>> > > > On 09/19/2018 15:56, JC Beyler wrote:
>>> > > > > Hi Alex,
>>> > > > >
>>> > > > > I've updated the webrev to:
>>> > > > > Webrev:
>>> > > http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.02/
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.02/>
>>> > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.02/>
>>> > > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.02/>
>>> > > > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.02/>
>>> > > > > Bug:
>>> > https://bugs.openjdk.java.net/browse/JDK-8210842
>>> > > > >
>>> > > > > That webrev has the code that is shown here in
>>> > snippets.
>>> > > > >
>>> > > > >
>>> > > > > Thanks for the reviews, I've relatively
>>> > followed your reviews
>>> > > > except for
>>> > > > > one detail due to me wanting to handle the
>>> > NSK_JNI_VERIFY
>>> > > macros via
>>> > > > > this system as well later down the road. For
>>> > an
>>> > example:
>>> > > > >
>>> > > > > We currently have in the code:
>>> > > > > if ( ! NSK_JNI_VERIFY(pEnv, (mhClass =
>>> > > NSK_CPP_STUB2(GetObjectClass,
>>> > > > > pEnv, mhToCall)) != NULL) )
>>> > > > >
>>> > > > > 1) The NSK_CPP_STUB2 is trivially removed with
>>> > a refactor
>>> > > > (JDK-8210728)
>>> > > > >
>>> > <https://bugs.openjdk.java.net/browse/JDK-8210728> to:
>>> > > > > if ( ! NSK_JNI_VERIFY(pEnv, (mhClass =
>>> > > pEnv->GetObjectClass(pEnv,
>>> > > > > mhToCall)) != NULL) )
>>> > > > >
>>> > > > > 2) Then the NSK_JNI_VERIFY, I'd like to remove
>>> > it to and it
>>> > > > becomes via
>>> > > > > this wrapping of JNIEnv:
>>> > > > > if ( ! (mhClass = pEnv->GetObjectClass(pEnv,
>>> > mhToCall)) )
>>> > > > >
>>> > > > > 3) Then, via removing the assignment, we'd
>>> > arrive to a:
>>> > > > > mhClass = pEnv->GetObjectClass(pEnv,
>>> > mhToCall));
>>> > > > > if (!mhClass)
>>> > > > >
>>> > > > > Without any loss of checking for failures,
>>> > etc.
>>> > > > >
>>> > > > > So that is my motivation for most of this work
>>> > with a concrete
>>> > > > example
>>> > > > > (hopefully it helps drive this conversation).
>>> > > > >
>>> > > > > I inlined my answers here, let me know what
>>> > you
>>> > think.
>>> > > > >
>>> > > > > On Wed, Sep 19, 2018 at 2:30 PM Alex Menkov
>>> > > > <alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>
>>> > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>>
>>> > > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>
>>> > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>>>
>>> > > > > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>
>>> > > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>>
>>> > > > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>
>>> > > <mailto:alexey.menkov at oracle.com
>>> > <mailto:alexey.menkov at oracle.com>>>>> wrote:
>>> > > > >
>>> > > > > Hi Jc,
>>> > > > >
>>> > > > > Updated tests looks good.
>>> > > > > Some notes about implementation.
>>> > > > >
>>> > > > > - FatalOnException implements both
>>> > verification and error
>>> > > > handling
>>> > > > > It would be better to separate them (and
>>> > this makes
>>> > > easy to
>>> > > > implement
>>> > > > > error handling different from
>>> > JNIEnv::FatalError).
>>> > > > > The simplest way is to define error
>>> > handler as
>>> > > > > class SafeJNIEnv {
>>> > > > > public:
>>> > > > > typedef void (*ErrorHandler)(JNIEnv
>>> > *env, const
>>> > > char*
>>> > > > errorMsg);
>>> > > > > // error handler which terminates
>>> > jvm
>>> > by using
>>> > > FatalError()
>>> > > > > static void FatalError(JNIEnv *env,
>>> > const char
>>> > > *errrorMsg);
>>> > > > >
>>> > > > > SafeJNIEnv(JNIEnv* jni_env,
>>> > ErrorHandler
>>> > > errorHandler =
>>> > > > > FatalError);
>>> > > > > (SafeJNIEnv methods should create
>>> > FatalOnException objects
>>> > > > passing
>>> > > > > errorHandler)
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > > > Agreed, I tried to keep the code simple. The
>>> > concepts you
>>> > > talk about
>>> > > > > here are generally what I reserve for when I
>>> > need it (ie
>>> > > > extensions and
>>> > > > > handling new cases). But a lot are going to be
>>> > needed soon
>>> > > so I
>>> > > > think it
>>> > > > > is a good time to iron the code out now on
>>> > this
>>> > "simple"
>>> > > webrev.
>>> > > > >
>>> > > > > So done for this.
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > > > - FatalOnException is used in SafeJNIEnv
>>> > methods as
>>> > > > > FatalOnException marker(this, "msg");
>>> > > > > ret = <JNI call>
>>> > > > > (optional)marker.check_for_null(ret);
>>> > > > > return ret;
>>> > > > > But actually I'd call it something like
>>> > > JNICallResultVerifier and
>>> > > > > create
>>> > > > > the object after JNI call. like
>>> > > > > ret = <JNI call>
>>> > > > > JNICallResultVerifier(this, "msg")
>>> > > > > (optional).notNull(ret);
>>> > > > > return ret;
>>> > > > > or even (if you like such syntax sugar)
>>> > you
>>> > can define
>>> > > > > template<typename T>
>>> > > > > T resultNotNull(T result) {
>>> > > > > notNull(result);
>>> > > > > return result;
>>> > > > > }
>>> > > > > and do
>>> > > > > ret = <JNI call>
>>> > > > > return JNICallResultVerifier(this,
>>> > > "msg").resultNotNull(ret);
>>> > > > >
>>> > > > >
>>> > > > > So I renamed FatalOnException to now being
>>> > JNIVerifier.
>>> > > > >
>>> > > > > Though I like it, I don't think we can do it,
>>> > except if we
>>> > > do it
>>> > > > > slightly differently:
>>> > > > > I'm trying to solve two problems with one
>>> > stone:
>>> > > > > - How to check for returns of JNI calls in
>>> > the way that is
>>> > > > done here
>>> > > > > - How to remove NSK_JNI_VERIFY* (from
>>> > > nsk/share/jni/jni_tools)
>>> > > > >
>>> > > > > However, the NSK_JNI_VERIFY need to start a
>>> > tracing system
>>> > > before
>>> > > > the
>>> > > > > call to JNI, so it won't work this way. (Side
>>> > question
>>> > > would be
>>> > > > do we
>>> > > > > still care about the tracing in
>>> > NSK_JNI_VERIFY,
>>> > if we
>>> > > don't then
>>> > > > your
>>> > > > > solution works well in most situations).
>>> > > > >
>>> > > > > My vision or intuition is that we would throw
>>> > a
>>> > template
>>> > > at some
>>> > > > point
>>> > > > > on SafeJNIEnv to handle both cases and have
>>> > JNIVerifier
>>> > > become a
>>> > > > > specialization in certain cases and something
>>> > different
>>> > > for the
>>> > > > > NSK_JNI_VERIFY case (or have a different
>>> > constructor to enable
>>> > > > tracing).
>>> > > > > But for now, I offer the implementation that
>>> > does:
>>> > > > >
>>> > > > > jclass SafeJNIEnv::GetObjectClass(jobject obj)
>>> > {
>>> > > > > JNIVerifier<jclass> marker(this,
>>> > "GetObjectClass");
>>> > > > > return
>>> > marker.ResultNotNull(_jni_env->GetObjectClass(obj));
>>> > > > > }
>>> > > > >
>>> > > > > and:
>>> > > > >
>>> > > > > void SafeJNIEnv::SetObjectField(jobject obj,
>>> > jfieldID
>>> > > field, jobject
>>> > > > > value) {
>>> > > > > JNIVerifier<> marker(this,
>>> > "SetObjectField");
>>> > > > > _jni_env->SetObjectField(obj, field,
>>> > value);
>>> > > > > }
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > > > - you added #include <memory> in the test
>>> > (and you have to
>>> > > > add it to
>>> > > > > every test).
>>> > > > > It would be simpler to add the include to
>>> > > SafeJNIEnv.hpp and
>>> > > > define
>>> > > > > typedef std::unique_ptr<SafeJNIEnv>
>>> > SafeJNIEnvPtr;
>>> > > > > Then each in the test methods:
>>> > > > > SafeJNIEnvPtr env(new
>>> > SafeJNIEnv(jni_env));
>>> > > > > or you can add
>>> > > > > static SafeJNIEnv::SafeJNIEnvPtr
>>> > wrap(JNIEnv* jni_env,
>>> > > > ErrorHandler
>>> > > > > errorHandler = fatalError)
>>> > > > > and get
>>> > > > > SafeJNIEnvPtr env =
>>> > SafeJNIEnv::wrap(jni_env);
>>> > > > >
>>> > > > >
>>> > > > > Done, I like that, even less code change to
>>> > tests then.
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > > > - it would be better to wrap internal
>>> > classes
>>> > > > (FatalOnException) into
>>> > > > > unnamed namespace - this helps to avoid
>>> > conflicts with
>>> > > other
>>> > > > classes)
>>> > > > >
>>> > > > > - FatalOnException::check_for_null(void*
>>> > ptr)
>>> > > > > should be
>>> > > > > FatalOnException::check_for_null(const
>>> > void* ptr)
>>> > > > > And calling the method you don't need
>>> > reinterpret_cast
>>> > > > >
>>> > > > >
>>> > > > > Also done, it got renamed to ResultNotNull, is
>>> > using a
>>> > > template
>>> > > > now, but
>>> > > > > agreed, that worked.
>>> > > > > Thanks again for the review,
>>> > > > > Jc
>>> > > > >
>>> > > > >
>>> > > > > --alex
>>> > > > >
>>> > > > >
>>> > > > > On 09/18/2018 11:07, JC Beyler wrote:
>>> > > > > > Hi David,
>>> > > > > >
>>> > > > > > Thanks for the quick review and
>>> > thoughts. I have
>>> > > now a new
>>> > > > > version here
>>> > > > > > that addresses your comments:
>>> > > > > >
>>> > > > > > Webrev:
>>> > > >
>>> > http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.01/
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/>
>>> > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/>
>>> > > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/>
>>> > > > >
>>> > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/>
>>> > > > > >
>>> > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/>
>>> > > > > >
>>> > Bug:https://bugs.openjdk.java.net/browse/JDK-8210842
>>> > > > > >
>>> > > > > > I've also inlined my answers/comments.
>>> > > > > >
>>> > > > > >
>>> > > > > >
>>> > > > > > > I've slowly started working on
>>> > JDK-8191519
>>> > > > > > >
>>> > > <https://bugs.openjdk.java.net/browse/JDK-8191519>.
>>> > > > > However before
>>> > > > > > > starting to really refactor all
>>> > the tests, I
>>> > > > thought I'd
>>> > > > > get a few
>>> > > > > > > opinions. I am working on
>>> > internalizing the
>>> > > error
>>> > > > handling
>>> > > > > of JNI
>>> > > > > > calls
>>> > > > > > > via a SafeJNIEnv class that
>>> > redefines all
>>> > > the JNI
>>> > > > calls to
>>> > > > > add an
>>> > > > > > error
>>> > > > > > > checker.
>>> > > > > > >
>>> > > > > > > The advantage is that the test
>>> > code will
>>> > > look and
>>> > > > feel like
>>> > > > > > normal JNI
>>> > > > > > > code and calls but will have the
>>> > checks we
>>> > > want to have
>>> > > > > for our
>>> > > > > > tests.
>>> > > > > >
>>> > > > > > Not sure I get that. Normal JNI
>>> > code
>>> > has to
>>> > > check for
>>> > > > > errors/exceptions
>>> > > > > > after every call. The tests need
>>> > those checks too.
>>> > > > Today they are
>>> > > > > > explicit, with this change they
>>> > become
>>> > > implicit. Not sure
>>> > > > > what we are
>>> > > > > > gaining here ??
>>> > > > > >
>>> > > > > >
>>> > > > > > In my humble opinion, having the error
>>> > checking out
>>> > > of the way
>>> > > > > allows
>>> > > > > > the code reader to concentrate on the
>>> > JNI code while
>>> > > > maintaining
>>> > > > > error
>>> > > > > > checking. We use something similar
>>> > internally, so
>>> > > perhaps I'm
>>> > > > > biased to
>>> > > > > > it :-).
>>> > > > > > If this is not a desired/helpful
>>> > "feature" to simplify
>>> > > > tests in
>>> > > > > general,
>>> > > > > > I will backtrack it and just add the
>>> > explicit tests
>>> > > to the
>>> > > > native
>>> > > > > code
>>> > > > > > of the locks for the fix
>>> > > > > >
>>> > > https://bugs.openjdk.java.net/browse/JDK-8191519 instead.
>>> > > > > >
>>> > > > > > Let me however try to make my case and
>>> > let me know what
>>> > > > you all
>>> > > > > think!
>>> > > > > >
>>> > > > > >
>>> > > > > > > If agreed with this, we can
>>> > augment the
>>> > > SafeJNIEnv
>>> > > > class
>>> > > > > as needed.
>>> > > > > > > Also, if the tests require
>>> > something else
>>> > > than fatal
>>> > > > > errors, we
>>> > > > > > can add
>>> > > > > > > a different marker and make it a
>>> > parameter
>>> > > to the
>>> > > > base class.
>>> > > > > > >
>>> > > > > > > Webrev:
>>> > > > >
>>> > http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.00/
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.00/>
>>> > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.00/>
>>> > > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.00/>
>>> > > > >
>>> > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.00/>
>>> > > > > >
>>> > > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.00/>
>>> > > > > > >
>>> > > >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.00/>
>>> > > > > > > Bug:
>>> > > https://bugs.openjdk.java.net/browse/JDK-8210842
>>> > > > > > >
>>> > > > > > > Let me know what you think,
>>> > > > > >
>>> > > > > > Two initial suggestions:
>>> > > > > >
>>> > > > > > 1. FatalOnException should be
>>> > constructed with a
>>> > > > description
>>> > > > > string so
>>> > > > > > that it can report the failing
>>> > operation when
>>> > > calling
>>> > > > > FatalError rather
>>> > > > > > than the general "Problem with a
>>> > JNI
>>> > call".
>>> > > > > >
>>> > > > > >
>>> > > > > > Agreed with you, the new webrev
>>> > produces:
>>> > > > > >
>>> > > > > > FATAL ERROR in native method:
>>> > GetObjectClass
>>> > > > > > at
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > nsk.share.gc.lock.CriticalSectionTimedLocker.criticalSection(CriticalSectionTimedLocker.java:47)
>>> > > > > > at
>>> > > > >
>>> > >
>>> >
>>> > nsk.share.gc.lock.jniref.JNIGlobalRefLocker.criticalNative(Native
>>> > > > > Method)
>>> > > > > > at
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > nsk.share.gc.lock.jniref.JNIGlobalRefLocker.criticalSection(JNIGlobalRefLocker.java:44)
>>> > > > > > at
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > nsk.share.gc.lock.CriticalSectionLocker$1.run(CriticalSectionLocker.java:56)
>>> > > > > > at
>>> > > > >
>>> > >
>>> > java.lang.Thread.run(java.base at 12-internal/Thread.java:834)
>>> > > > > >
>>> > > > > >
>>> > > > > > and for a return NULL in NewGlobalRef,
>>> > we would get
>>> > > > automatically:
>>> > > > > >
>>> > > > > > FATAL ERROR in native method:
>>> > NewGlobalRef:Return
>>> > > is NULL
>>> > > > > > at
>>> > > > >
>>> > >
>>> >
>>> > nsk.share.gc.lock.jniref.JNIGlobalRefLocker.criticalNative(Native
>>> > > > > Method)
>>> > > > > >
>>> > > > > > at
>>> > > > > >
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > nsk.share.gc.lock.jniref.JNIGlobalRefLocker.criticalSection(JNIGlobalRefLocker.java:44)
>>> > > > >
>>> > > > > >
>>> > > > > >
>>> > > > > >
>>> > > > > > Again as we port and simplify more
>>> > tests
>>> > (I'll only
>>> > > do the
>>> > > > locks
>>> > > > > for now
>>> > > > > > and we can figure out the next steps as
>>> > start
>>> > > working on
>>> > > > moving
>>> > > > > tests
>>> > > > > > out of vmTestbase),
>>> > > > > > we can add, if needed, other exception
>>> > handlers
>>> > > that don't
>>> > > > throw
>>> > > > > or do
>>> > > > > > other things depending on the JNI
>>> > method
>>> > outputs.
>>> > > > > >
>>> > > > > >
>>> > > > > > 2. Make the local SafeJNIEnv a
>>> > pointer called
>>> > > env so
>>> > > > that the
>>> > > > > change is
>>> > > > > > less disruptive. All the env->op()
>>> > calls will
>>> > > remain
>>> > > > and only
>>> > > > > the local
>>> > > > > > error checking will be removed.
>>> > > > > >
>>> > > > > >
>>> > > > > > Done, I used a unique_ptr to make the
>>> > object
>>> > > > > created/destroyed/available
>>> > > > > > as a pointer do-able in one line:
>>> > > > > > std::unique_ptr<SafeJNIEnv> env(new
>>> > > SafeJNIEnv(jni_env));
>>> > > > > >
>>> > > > > > and then you can see that, as you
>>> > mentioned, the
>>> > > disruption to
>>> > > > > the code
>>> > > > > > is much less:
>>> > > > > >
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.udiff.html
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.udiff.html>
>>> > >
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.udiff.html>
>>> > > >
>>> > >
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.udiff.html>
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.udiff.html>
>>> > > > >
>>> > > > > >
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.udiff.html>
>>> > > > > >
>>> > > > > > Basically the tests now become internal
>>> > to the
>>> > > SafeJNIEnv
>>> > > > and the
>>> > > > > code
>>> > > > > > now only contains the JNI calls
>>> > happening but we
>>> > > are protected
>>> > > > > and will
>>> > > > > > fail any test that has an exception or
>>> > a
>>> > NULL
>>> > > return for the
>>> > > > > call. Of
>>> > > > > > course, this is not 100% proof in terms
>>> > of not
>>> > > having any
>>> > > > error
>>> > > > > handling
>>> > > > > > in the test but in some cases like
>>> > this,
>>> > the new
>>> > > code seems to
>>> > > > > just work
>>> > > > > > better:
>>> > > > > >
>>> > > > > >
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > http://cr.openjdk.java.net/~jcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.html
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.html>
>>> > >
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.html>
>>> > > >
>>> > >
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.html>
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.html>
>>> > > > >
>>> > > > > >
>>> > > > >
>>> > > >
>>> > >
>>> >
>>> > <http://cr.openjdk.java.net/%7Ejcbeyler/8210842/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp.html>
>>> > > > > >
>>> > > > > >
>>> > > > > >
>>> > > > > > The switch from, e.g., checking
>>> > NULL
>>> > returns to
>>> > > > checking for
>>> > > > > pending
>>> > > > > > exceptions, need to be sure that
>>> > the
>>> > JNI operations
>>> > > > clearly
>>> > > > > specify
>>> > > > > > that
>>> > > > > > NULL implies there will be an
>>> > exception
>>> > > pending. This
>>> > > > change
>>> > > > > may be an
>>> > > > > > issue for static code analysis if
>>> > not smart
>>> > > enough to
>>> > > > > understand the
>>> > > > > > RAII wrappers.
>>> > > > > >
>>> > > > > >
>>> > > > > > Agreed, I fixed it to be more strict
>>> > and
>>> > say: in
>>> > > normal test
>>> > > > > handling,
>>> > > > > > the JNI calls should never return NULL
>>> > or throw an
>>> > > > exception. This
>>> > > > > > should hold for tests I imagine but if
>>> > not we can add a
>>> > > > different
>>> > > > > call
>>> > > > > > verifier as we go.
>>> > > > > >
>>> > > > > >
>>> > > > > > Thanks,
>>> > > > > > David
>>> > > > > >
>>> > > > > > > Jc
>>> > > > > >
>>> > > > > >
>>> > > > > >
>>> > > > > > Let me know what you all think. When
>>> > talking about it a
>>> > > > bit, I had
>>> > > > > > gotten some interest to see what it
>>> > would look
>>> > > like. Here
>>> > > > it is
>>> > > > > :-). Now
>>> > > > > > if it is not wanted like I said, I can
>>> > backtrack
>>> > > and just
>>> > > > put the
>>> > > > > error
>>> > > > > > checks after each JNI call for all the
>>> > tests as we are
>>> > > > porting them.
>>> > > > > > Jc
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > > > --
>>> > > > >
>>> > >
>
>
>
> --
>
> Thanks,
> Jc
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