[PATCH] D93267: [lld-macho] Handle overflow beyond the 127 common encodings limit

[Greg McGary via Phabricator via llvm-commits]

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The common encodings table holds only 127 entries. The encodings index for compact entries is 8 bits wide, and indexes 127..255 are stored locally to each second-level page. Prior to this diff, lld would `fatal()` if encodings overflowed the 127 limit.

This diff populates a per-second-level-page encodings table as needed. When the per-page encodings table hits its limit, we must terminate the page. If such early termination would consume fewer entries than a regular (non-compact) encoding page, then we prefer the regular format.

Caveat: one reason the common-encoding table might overflow is because of DWARF debug-info references, which are not yet implemented and will come with a later diff.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D93267

Files:
  lld/MachO/UnwindInfoSection.cpp
  lld/MachO/UnwindInfoSection.h
  lld/test/MachO/tools/generate-cfi-funcs.py
  lld/test/MachO/tools/validate-unwind-info.py

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