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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Linked bytecode should not have save/resume"
href="https://bugs.webkit.org/show_bug.cgi?id=159281">159281</a>
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<th>Summary</th>
<td>Linked bytecode should not have save/resume
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<th>Classification</th>
<td>Unclassified
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<th>Product</th>
<td>WebKit
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<th>Version</th>
<td>WebKit Nightly Build
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<th>Hardware</th>
<td>All
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>Normal
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<th>Priority</th>
<td>P2
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<th>Component</th>
<td>JavaScriptCore
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<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
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<th>Reporter</th>
<td>fpizlo@apple.com
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<p>
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<pre>The save/resume opcodes are so unusual that they cause confusion in the bytecode liveness analysis. In particular, they don't have context-free use/def behavior and their live-in calculation cannot be expressed in terms of use/def. Normally, the use/def of a bytecode is determined just by that bytecode. Save/resume's use/def is context-sensitive: you need to look at some surrounding code to determine what they use and def. Worse, use/def is insufficient to calculate the live-in of resume. The live-in of resume is invariant: the only thing live-in is the argument token. This is an unusual rule, and would require resume to be special-cased.
Linked bytecode has many clients: the bytecode liveness analysis, the LLInt, baseline JIT, and DFG parser. I think that instead of having so many special cases in linked bytecode for generators, we should do a generator conversion before even getting to linked bytecode. This will mean that linked bytecode won't have to worry about what it means to be a generator.</pre>
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