tree 7825438a5c5ff8c1b8bfae828bec3bd5a7ce0aab
parent 29ee8fb372bd38526fc19fda3567cb5fa387abc5
author Sterling Augustine <saugustine@google.com> 1583539156 -0800
committer Copybara-Service <copybara-worker@google.com> 1598638562 -0700

Rework findUnwindSectionsByPhdr to be more optimal.

Summary:
- Executable segment is usually segment 3. Look there for the address first.
- GNU_EH_FRAME_HEADER segment is usually near the end. Iterate from the end.
- Exit early if both phdrs have been found.

This is the last cl before a patch to cache the information this function
finds.

Subscribers: libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D75781

GitOrigin-RevId: d67cf7a0a970df6e69db437514bf61a2ab283e67