Previously, if you add two comdat symbols as a result of LTO,
they are reported as duplicate symbols because comdat symbols
are not uniquified after LTO.
This patch allows LTO to add comdat symbols. The DenseSet contains
comdat symbols we've seen so far. Instead of discarding the DenseSet
for each file reading, we use the same set to read all compiled
native object files.
I have a few questions about this patch though:
- Is it assumed for LTO to add new comdat symbols as a result of LTO?
- How can I test this patch?