[PATCH] D70243: Lowering CPI/JTI/BA to assembly

[Jason Liu via Phabricator via llvm-commits]

jasonliu added a comment.

Some observation for constant pool lowering:
We put all the constant pool data into rodata section, and create one TC entry per constant pool reference.
It hinders the ability for linker to garbage collect unused data. (Generates them into a separate RO section helps a bit, but won't fully solve this issue)
And we would also create a lot of TC entries for constant pool that might not get cleanup.

For comparison, gcc generates the value of constant pool data directly into the TC entry. It's faster and garbage collectable if not used.
xlC generates all the constant pool data in a single csect, but reference different data with one TC entry. Less efficient, but still less TC entry generated, and it does not mess with the other rodata.

So with this implementation, it would work functionally. But performance and space wise, could not compare to the other two compilers.
I'm Okay with moving forward with some TODOs in our mind.


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D70243