[ELF] ICF optimizations and simplifications #845
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A node converges if its descendants contains no cycles and its hash has reached all its descendants. Previously we checked for convergence on each iteration by comparing hashes, but this could be tracked more cheaply through a separate bitset. This improves cache efficiency and results in a ~50ms speed up for Chromium out of 310ms for the ICF pass. Signed-off-by: Tatsuyuki Ishi <ishitatsuyuki@gmail.com>
This isn't perf intensive at all but sweeping through the sections seems to be the more obvious way compared to going through the symbol indirections. Also, reword the comments and timing name to better reflect what it's doing. FWIW, it's slightly (5ms) faster. Signed-off-by: Tatsuyuki Ishi <ishitatsuyuki@gmail.com>
We can already print them, but a counter is more handy when the executable is large and dumping everything would be too much. Signed-off-by: Tatsuyuki Ishi <ishitatsuyuki@gmail.com>
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I wonder if you can use |
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The specialization on |
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Hm actually it wasn't removed (the proposal was rejected), but it's widely considered a mistake anyway and I don't think it's worth using given it lacks ability to do a fast "count last zero" operation anyway. |
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Implements the low-hanging fruit from #842, and a few additional simplifications while on it.