[llvm] [llvm][docs] Add notes on upstreaming code from downstream projects (PR #129743)

[Andrzej Warzyński via llvm-commits]

================
@@ -272,3 +272,19 @@ Developers should participate in code reviews as both reviewers and
 authors. If someone is kind enough to review your code, you should return the
 favor for someone else. Note that anyone is welcome to review and give feedback
 on a patch, but approval of patches should be consistent with the policy above.
+
+Upstreaming Changes to LLVM
+===========================
+
+When upstreaming your own changes from a downstream project to LLVM, simply
+follow the process outlined above.
+
+When upstreaming changes originally written by someone else:  
+
+* Ensure that the original author(s) are aware of and approve the upstreaming
+  of their code, and that they are comfortable with you leading the process.
----------------
banach-space wrote:

While waiting for Kristof to chime in, do you have any suggestions how to re-phrase this? Here's what I have in mind:
> Ensure that there are no obstacles to upstreaming the code. In some cases, this simply means checking with the original author(s) to ensure they are aware of and approve the upstreaming.

Would that address your concerns? From my perspective, this conveys everything that I originally intended.


https://github.com/llvm/llvm-project/pull/129743