tree d4886cdc1ecc42f1c4902c3bfce5d652ac83a892
parent 6a0ea660792a7f7761890df2df379e26d6a76d53
author alx32 <103613512+alx32@users.noreply.github.com> 1711585671 -0700
committer Copybara-Service <copybara-worker@google.com> 1711586814 -0700

[lld-macho] Fix bug in makeSyntheticInputSection when -dead_strip flag is specified (#86878)

Previously, `makeSyntheticInputSection` would create a new
`ConcatInputSection` without setting `live` explicitly for it. Without
`-dead_strip` this would be OK since `live` would default to `true`.
However, with `-dead_strip`, `live` would default to false, and it would
remain set to `false`.
This hasn't resulted in any issues so far since no code paths that
exposed this issue were present.
However a recent change - ObjC relative method lists
(https://github.com/llvm/llvm-project/pull/86231) exposes this issue by
creating relocations to the `SyntheticInputSection`.
When these relocations are attempted to be written, this ends up with a
crash(assert), since the `SyntheticInputSection` they refer to is marked
as dead (`live` = `false`).

With this change, we set the correct behavior - `live` will always be
`true`. We add a test case that before this change would trigger an
assert in the linker.

GitOrigin-RevId: bbfa50696e43f337f55f8bacf739683b181debd5