[PATCH] D66941: [DebugInfo] LiveDebugValues: explicitly terminate overwritten stack locations

[Jeremy Morse via Phabricator via llvm-commits]

jmorse added inline comments.


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Comment at: lib/CodeGen/LiveDebugValues.cpp:881
+        // the open range, and insert an explicit DBG_VALUE $noreg. Reg clobbers
+        // can be detected by DbgEntityHistoryCalculator, but stack writes are
+        // not.
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aprantl wrote:
> One last question: Could/should we fix this in DbgEntityHistoryCalculator instead?
Overall it would make more sense to fix it in DbgEntityHistoryCalculator, that way the two logically similar things (working out when a location no longer contains the desired value) would happen in the same place. However, doing so would require parsing a DIExpression to work out where in the stack frame a DBG_VALUE points, which IMO is generally a bad plan.

My feeling is that creating some undef DBG_VALUEs here where the information is readily available is better than parsing a DIExpression at a later stage.


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  https://reviews.llvm.org/D66941/new/

https://reviews.llvm.org/D66941