Fangrui Song e390bda978 [ELF] Suppress --no-allow-shlib-undefined diagnostic when a SharedSymbol is overridden by a hidden visibility Defined which is later discarded ...

Commit 1981b1b6b9 unexpectedly strengthened
--no-allow-shlib-undefined to catch a kind of ODR violation.
More precisely, when all three conditions are met, the new
`--no-allow-shlib-undefined` code reports an error.

* There is a DSO undef that has been satisfied by a definition from
  another DSO.
* The `SharedSymbol` is overridden by a non-exported (usually of hidden
  visibility) definition in a relocatable object file (`Defined`).
* The section containing the `Defined` is garbage-collected (it is not
  part of `.dynsym` and is not marked as live).

Technically, the hidden Defined in the executable can be intentional: it
can be meant to remain non-exported and not interact with any dynamic
symbols of the same name that might exist in other DSOs. To allow for
such use cases, allocate a new bit in
Symbol and relax the --no-allow-shlib-undefined check to before
commit 1981b1b6b9.

2024-01-22 10:09:35 -08:00

69 KiB

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