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Hi Mark,</div>
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This indeed is weird - the ClassFile API's generation should force another branching check at bci 6 against the handler at 36 for frame compatibility, and should fail there. Unfortunately, I am busy with other projects right now and cannot divest a lot of time
investigating this; can you try creating a minimal reproduction, like a simple method that has a try-catch and a post action, and a very simple transform, both of which don't require extra library dependencies?</div>
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Regards, Chen</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Mark Roberts <markro@cs.washington.edu><br>
<b>Sent:</b> Tuesday, January 28, 2025 2:45 PM<br>
<b>To:</b> classfile-api-dev@openjdk.org <classfile-api-dev@openjdk.org><br>
<b>Cc:</b> Chen Liang <chen.l.liang@oracle.com><br>
<b>Subject:</b> [External] : StackMap problem</font>
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<p class="x_MsoNormal">The existence of compiler generated, unnamed local temps (no LocalVariable code element) seems to cause a problem with stack maps.</p>
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<p class="x_MsoNormal">The ‘source’ attachment shows the problem method. The ‘before’ attachment shows the generated code before instrumentation. Note that the compiler generates an unnamed temp at slot 0 to store the exception code. The stackmap for the
branch target says same locals, which is correct.</p>
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<p class="x_MsoNormal">The ‘after’ attachment shows the code generated after our tool has added instrumentation code – note the addition of a new local variable at slot 1. The stackmap for the branch target still says same locals, which is no longer correct.
This causes the iload_1 @41 to fail.</p>
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<p class="x_MsoNormal">I tried to see if this issue has already been reported, but I was unable to figure out how to search
<a href="https://urldefense.com/v3/__https://bugs.java.com/bugdatabase/__;!!ACWV5N9M2RV99hQ!J8Z_mD-T0Ps_kClOITgamtTMlXOdh7853QyTHD_sdbzUyIjKujz-4jcUs9Y0Y7iKjgO6vAwjbQvGbgT91qY0mw519Q$">
https://bugs.java.com/bugdatabase/</a> by keyword.</p>
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<p class="x_MsoNormal">Mark</p>
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