[PATCH] D69027: [llvm-dwarfdump][Statistics] Fix calculation of OffsetToFirstDefinition

[David Blaikie via Phabricator via llvm-commits]

dblaikie added a comment.

> + 1. I think the first set of statistics would give a decent overview of debug info quality, and the second (without any adjustments to enclosing scope sizes) would be more useful for evaluating individual changes. I worry that only having the second set of statistics would paint an unrealistically bleak picture.

I'm not sure the bleakness is as much of a problem (but I didn't implement/don't personally use the statistics at all) - like all the other measures, this would be a relative one, not one where "100%" was a goal/meaningful (& the only reason to view it as a % would be to understand progress in a relative sense, I guess? Though measuring it on exactly the same code as an absolute value would be fine and represent progress too)

If we are going to keep adjusted scope values - I'd love to hear a proposal that explains how to do so in a way that makes sense to me in the face of arbitrary basic block order - so far as I can think of, the only "adjusted scope bytes" that would make sense to me would be one that looks at each basic block (which would required disassembly to even identify, unfortunately) and has an adjusted scope of "first byte with a valid location description to last byte with a valid location description" within a scope subrange within a basic block. Anything else seems not very meaningful to me due to basic block order being unspecified (& maybe based on profile driven optimization, etc).


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https://reviews.llvm.org/D69027