[libcxx-commits] [PATCH] D151814: libc++][modules] Adds the C++23 std module.

[Aaron Siddhartha Mondal via Phabricator via libcxx-commits]

aaronmondal added inline comments.


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Comment at: libcxx/docs/Modules.rst:65
+      `bug report <https://github.com/llvm/llvm-project/issues/61465>`__.
+
+Blockers
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Mordante wrote:
> aaronmondal wrote:
> > As a safeguard we might want to add the note that the BMIs shouldn't be distributed at the moment. AFAIK BMIs still contain absolute paths to their build environment. I.e. if you build at `/my/custom/build/machine` this path will be printed if you run `strings` on the BMIs. This could leak information from a distributors build environment to the BMI.
> I'm not sure that is needed. I feel there are already quite some warnings that BMIs are not portable. At least on Debian in the past, debug packages "leaked" the same information, which didn't seem to be an issue.
> 
> Do you have reasons why this is a real issue?
If you have a build that indexes cached artifacts by hash this can lead to confusing cache behavior for incremental builds. Having the cache poisoned by this essentially forces you to completely delete it and rebuild everything. For LLVM this is roughly 200GB of wasted cache transfer and ~10 hours of wasted single thread CPU minutes. This probably isn't an issue for most users though and since modules are experimental anyways it's probably a non-issue.


Repository:
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  https://reviews.llvm.org/D151814/new/

https://reviews.llvm.org/D151814