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    <div class="moz-cite-prefix">Hi Igor,<br>
      <br>
      +1<br>
      <br>
      Thanks,<br>
      Serguei<br>
      <br>
      <br>
      On 11/29/18 07:42, <a class="moz-txt-link-abbreviated" href="mailto:dean.long@oracle.com">dean.long@oracle.com</a> wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:99965d21-854d-eaf7-8de6-272defaff5e0@oracle.com"> OK
      your fix looks good.<br>
      <br>
      dl<br>
      <br>
      <div class="moz-cite-prefix">On 11/28/18 10:57 PM, Igor Veresov
        wrote:<br>
      </div>
      <blockquote type="cite"
        cite="mid:A661D7FE-AE79-4D25-BE73-6C3AB82E112B@oracle.com">
        <div class="">It would work right now. But I don’t want us
          fixing it again when somebody implements effectively final
          optimization in Graal.</div>
        <br class="">
        <div class=""> <span class="Apple-style-span">igor<br class="">
            <br class="">
            <br class="">
          </span> </div>
        <div><br class="">
          <blockquote type="cite" class="">
            <div class="">On Nov 28, 2018, at 10:02 PM, <a
                href="mailto:dean.long@oracle.com" class=""
                moz-do-not-send="true">dean.long@oracle.com</a> wrote:</div>
            <br class="Apple-interchange-newline">
            <div class="">
              <div class=""> I like it better.  But do you really need
                to use JNI to reset the values?  If you had<br class="">
                <br class="">
                <tt class="">static int POISON = 0x1234;  // not final</tt><tt
                  class=""><br class="">
                </tt><tt class=""><br class="">
                </tt><tt class="">class TaggedClass {</tt><tt class=""><br
                    class="">
                </tt><tt class="">      static int field1 = 0xC0DE01 +
                  POISON;</tt><br class="">
                <br class="">
                in HeapFilter.java, is the compiler smart enough to
                treat the value as constant until it changes?<br
                  class="">
                <br class="">
                dl<br class="">
                <br class="">
                <div class="moz-cite-prefix">On 11/28/18 9:26 PM, Igor
                  Veresov wrote:<br class="">
                </div>
                <blockquote type="cite"
                  cite="mid:9D54BD55-2C2D-40DF-96BD-BDB0EB5CD4CC@oracle.com"
                  class="">
                  <div class="">Alright, how about the following
                    solution: <a
                      href="http://cr.openjdk.java.net/%7Eiveresov/8193577/webrev.01/"
                      class="" moz-do-not-send="true">http://cr.openjdk.java.net/~iveresov/8193577/webrev.01/</a></div>
                  <div class=""><br class="">
                  </div>
                  <div class=""> <span class="Apple-style-span">igor<br
                        class="">
                      <br class="">
                      <br class="">
                    </span> </div>
                  <div class=""><br class="">
                    <blockquote type="cite" class="">
                      <div class="">On Nov 28, 2018, at 4:59 PM, Igor
                        Veresov <<a
                          href="mailto:igor.veresov@oracle.com" class=""
                          moz-do-not-send="true">igor.veresov@oracle.com</a>>
                        wrote:</div>
                      <br class="Apple-interchange-newline">
                      <div class="">
                        <div class="">I don’t want to make it Graal
                          specific. I think I’ll just do field
                          assignments in native so that it’s all
                          invisible to the compiler.
                          <div class=""><br class="">
                            <div class=""> <span
                                class="Apple-style-span">igor<br
                                  class="">
                                <br class="">
                                <br class="">
                              </span> </div>
                            <div class=""><br class="">
                              <blockquote type="cite" class="">
                                <div class="">On Nov 28, 2018, at 3:25
                                  PM, <a
                                    href="mailto:serguei.spitsyn@oracle.com"
                                    class="" moz-do-not-send="true">serguei.spitsyn@oracle.com</a>
                                  wrote:</div>
                                <br class="Apple-interchange-newline">
                                <div class="">
                                  <div class="">
                                    <div class="moz-cite-prefix">On
                                      11/28/18 15:16, <a
                                        class="moz-txt-link-abbreviated"
href="mailto:dean.long@oracle.com" moz-do-not-send="true">dean.long@oracle.com</a>
                                      wrote:<br class="">
                                    </div>
                                    <blockquote type="cite"
                                      cite="mid:e97be0a0-89ca-1a1e-3c4f-77dcaba14230@oracle.com"
                                      class=""> It sounds like the test
                                      could also fail with C2 if the
                                      fields are in a virtual object
                                      that was eliminated.  I'm OK with
                                      your fix, but I would feel a
                                      little better if we only relaxed
                                      the check for Graal.  I guess
                                      you'd need to use the whitebox api
                                      for that.<br class="">
                                    </blockquote>
                                    <br class="">
                                    I was thinking about the same.<br
                                      class="">
                                    Relaxing this just for Graal sounds
                                    good.<br class="">
                                    On the other hand, making the test
                                    to know about Graal looks a little
                                    bit strange. :)<br class="">
                                    <br class="">
                                    Thanks,<br class="">
                                    Serguei <br class="">
                                    <br class="">
                                    <blockquote type="cite"
                                      cite="mid:e97be0a0-89ca-1a1e-3c4f-77dcaba14230@oracle.com"
                                      class=""> <br class="">
                                      dl<br class="">
                                      <br class="">
                                      <div class="moz-cite-prefix">On
                                        11/28/18 2:28 PM, Igor Veresov
                                        wrote:<br class="">
                                      </div>
                                      <blockquote type="cite"
                                        cite="mid:923D4C45-2684-41F6-9CD7-6C8D7BABBA5C@oracle.com"
                                        class="">
                                        <div class="">Oh, I haven’t
                                          understood your idea before
                                          pressing reply. Yes, we can
                                          match the objects by matching
                                          their shape, but it’s also not
                                          an exact solution prone to
                                          erroneous matches. Especially
                                          considering the iteration API
                                          does callbacks for the fields
                                          out of order - it does
                                          primitives, strings, arrays,
                                          in that order.</div>
                                        <div class=""><br class="">
                                        </div>
                                        <div class="">There are also
                                          ways to make it fail with
                                          Graal that are not related to
                                          constant representation. Graal
                                          treats allocations as side
                                          effect free. So it’s possible
                                          to allocate something and then
                                          deopt to a point before the
                                          allocation and redo the
                                          allocation in the interpreter.
                                          In this case there are going
                                          to be multiple objects on the
                                          heap with only one of them
                                          being reachable.</div>
                                        <div class=""><br class="">
                                        </div>
                                        <div class=""> <span
                                            class="Apple-style-span">igor<br
                                              class="">
                                            <br class="">
                                            <br class="">
                                          </span> </div>
                                        <div class=""><br class="">
                                          <blockquote type="cite"
                                            class="">
                                            <div class="">On Nov 28,
                                              2018, at 2:08 PM, Igor
                                              Veresov <<a
                                                href="mailto:igor.veresov@oracle.com"
                                                class=""
                                                moz-do-not-send="true">igor.veresov@oracle.com</a>>
                                              wrote:</div>
                                            <br
                                              class="Apple-interchange-newline">
                                            <div class="">
                                              <div class="">
                                                <div class="">I don’t
                                                  think there is a way
                                                  to identify an
                                                  untagged object. There
                                                  is nothing that is
                                                  passed in the callback
                                                  to allow that.</div>
                                                <br class="">
                                                <div class=""> <span
                                                    class="Apple-style-span">igor<br
                                                      class="">
                                                    <br class="">
                                                  </span> </div>
                                                <div class=""><br
                                                    class="">
                                                  <blockquote
                                                    type="cite" class="">
                                                    <div class="">On Nov
                                                      28, 2018, at 1:32
                                                      PM, <a
                                                        href="mailto:dean.long@oracle.com"
                                                        class=""
                                                        moz-do-not-send="true">dean.long@oracle.com</a>
                                                      wrote:</div>
                                                    <br
                                                      class="Apple-interchange-newline">
                                                    <div class="">
                                                      <div class="">I'm
                                                        guessing Graal
                                                        creates Constant
                                                        boxes of the
                                                        individual
                                                        fields and not
                                                        of the test
                                                        objects?  If so,
                                                        can't we fix the
                                                        matching so that
                                                        it checks that
                                                        all fields of an
                                                        object match?  I
                                                        guess that would
                                                        mean moving the
                                                        "expected" and
                                                        "found" counts
                                                        up from fields[]
                                                        to
                                                        objects_info[].<br
                                                          class="">
                                                        <br class="">
                                                        dl<br class="">
                                                        <br class="">
                                                        On 11/28/18 1:13
                                                        PM, Igor Veresov
                                                        wrote:<br
                                                          class="">
                                                        <blockquote
                                                          type="cite"
                                                          class="">When
                                                          doing heap
                                                          iteration with
                                                          JVMTI the way
                                                          the object
                                                          identity is
                                                          tracked is by
                                                          tagging. This
                                                          particular
                                                          test checks if
                                                          it  can
                                                          observe an
                                                          untagged
                                                          object. Since
                                                          there is no
                                                          way to truly
                                                          track the
                                                          identity of an
                                                          untagged
                                                          object the
                                                          test validates
                                                          the identity
                                                          by checking
                                                          the value of
                                                          the fields of
                                                          such object.
                                                          When being
                                                          compiled with
                                                          Graal there
                                                          are objects
                                                          produced (such
                                                          as Constant
                                                          boxes) that
                                                          have field
                                                          values that
                                                          are equal to
                                                          the expected
                                                          values for the
                                                          fields in
                                                          UntaggedClass.
                                                          During the
                                                          subsequent
                                                          heap iteration
                                                          these objects
                                                          are reported
                                                          to the test
                                                          and are
                                                          treated as if
                                                          they were
                                                          instances of
                                                          UntaggedClass.<br
                                                          class="">
                                                          <br class="">
                                                          The fix is to
                                                          relax the test
                                                          requirement
                                                          and allow (for
                                                          the untagged
                                                          case) the
                                                          number of the
                                                          object found
                                                          during
                                                          iteration to
                                                          be more than
                                                          expected.<br
                                                          class="">
                                                          <br class="">
                                                          Webrev: <a
                                                          href="http://cr.openjdk.java.net/%7Eiveresov/8193577/webrev.00/"
                                                          class=""
                                                          moz-do-not-send="true">http://cr.openjdk.java.net/~iveresov/8193577/webrev.00/</a><br
                                                          class="">
                                                          JBS: <a
                                                          href="https://bugs.openjdk.java.net/browse/JDK-8193577"
                                                          class=""
                                                          moz-do-not-send="true">https://bugs.openjdk.java.net/browse/JDK-8193577</a><br
                                                          class="">
                                                          <br class="">
                                                          igor<br
                                                          class="">
                                                          <br class="">
                                                          <br class="">
                                                          <br class="">
                                                        </blockquote>
                                                        <br class="">
                                                      </div>
                                                    </div>
                                                  </blockquote>
                                                </div>
                                                <br class="">
                                              </div>
                                            </div>
                                          </blockquote>
                                        </div>
                                        <br class="">
                                      </blockquote>
                                      <br class="">
                                    </blockquote>
                                    <br class="">
                                  </div>
                                </div>
                              </blockquote>
                            </div>
                            <br class="">
                          </div>
                        </div>
                      </div>
                    </blockquote>
                  </div>
                  <br class="">
                </blockquote>
                <br class="">
              </div>
            </div>
          </blockquote>
        </div>
        <br class="">
      </blockquote>
      <br>
    </blockquote>
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