RFR: 8263790: C2: new igv_print_immediately() for debugging purpose

[Roberto Castañeda Lozano]

On Fri, 19 Mar 2021 03:22:27 GMT, Yi Yang <yyang at openjdk.org> wrote:

>> Okay, that is strange that the closing tags are the only problem. I cannot reproduce this. What version of IGV are you using? Looking at your filters in the screenshot, I assume you are not using one of the most recent versions (there were some fixes/improvements recently done by @robcasloz including new default filters). You could try to build the latest version of IGV and try it again. Could you also share the failing `custom_debug.xml` file in the JBS issue?
>
> Sure, I have uploaded `custom_debug.xml` in JBS issue. I don't find an option like '-version' for idealgraphvisualizer. But from GUI->Preference->About, it shows `Version 1.0 (1.0)`.

Hi @kelthuzadx, I cannot reproduce the problem running the latest IGV on JDK 8 and linux-x64 either.

Note that IGV is designed to tolerate XML files without closing `</graphDocument>` and `</group>` tags. The parser does not use an error handler, which leads to ignoring all parsing errors [1], and on top of that certain parsing exceptions are ignored:

https://github.com/openjdk/jdk/blob/d24e4cfef36026b781906a9e0c5cf519eb72696e/src/utils/IdealGraphVisualizer/Data/src/com/sun/hotspot/igv/data/serialization/Parser.java#L531-L539

[1] https://docs.oracle.com/javase/8/docs/api/org/xml/sax/XMLReader.html#setErrorHandler-org.xml.sax.ErrorHandler-

Perhaps the problem you report should be addressed by making sure IGV also accepts missing closing `</graphDocument>` and `</group>` tags in your case? As you mention, this is a common debugging scenario.

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PR: https://git.openjdk.java.net/jdk/pull/3071