[libcxx-commits] [PATCH] D98129: [CMake][runtimes] Add file level dependency to merge_archives commands

Markus Böck via Phabricator via libcxx-commits libcxx-commits at lists.llvm.org
Mon Mar 8 11:02:49 PST 2021

zero9178 added a comment.

In D98129#2611778 <https://reviews.llvm.org/D98129#2611778>, @compnerd wrote:

> Im afraid I dont understand the purpose of this change.  libunwind isn't meant to be merged into libc++/libc++abi.  The reasoning for libc++ to support merging libc++abi doesn't really apply to libunwind IMO.  Can you please elaborate what exactly the reasoning for this is?

The option to merge libunwind into libc++abi has already existed prior to this patch since roughly 3 years. It's use case is mainly for static linking all parts of the runtime. The current implementation was created here: https://reviews.llvm.org/D60173 and the first implementation I could find that contained a discussion around the feature is here https://reviews.llvm.org/D39949.

What this patch adds is a simple file level dependency. If one was eg. doing incremental release builds and the sources of libunwind change, libunwind gets obviously rebuild. Currently, this would not lead to the merge script being run, therefore leading to any users of the toolchain working with an outdated version of libunwind. Likewise with libc++abi and libc++.

This patch simply adds a file level dependency, as is suggested by the cmake documentation, so that changes to libunwind would get merged into libc++abi and likewise with libc++abi into libc++.

  rG LLVM Github Monorepo



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