llvmPackages.stdenv: make Darwin a “system” libc++ platform #347388
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
github-actions
bot
added
6.topic: stdenv
ofborg
bot
added
6.topic: darwin
reckenrode
force-pushed
the
push-tvwkkqpyuwxr
branch
from
dad0fba
to
af52fa3
Compare
github-actions
bot
removed
the
6.topic: llvm/clang
reckenrode
force-pushed
the
push-tvwkkqpyuwxr
branch
from
af52fa3
to
74a9db5
Compare
github-actions
bot
added
the
6.topic: llvm/clang
13 tasks
reckenrode
force-pushed
the
push-tvwkkqpyuwxr
branch
from
74a9db5
to
bd57a74
Compare
Applying `overrideLibcxx` by default allows various LLVM versions to use the same underlying libc++ on Darwin. This works because libc++ is built by default with the stable ABI. Using the same libc++ regardless of LLVM version avoids potential ODR violations from linking multiple libc++ versions in the same process. This is similar to the default on Linux, which uses libstdc++ instead of libc++. On both platforms, to force a stdenv to link against that LLVM version’s libc++, use `libcxxStdenv`.
Take advantage of the fact that an overriden libc++ has the “system” version prepended to the new version, so it doesn’t get overriden again.
Darwin’s linkers support text-based stubs, which allows the override to use the “system” libc++ while limiting the symbols to those in the original version.
reckenrode
force-pushed
the
push-tvwkkqpyuwxr
branch
from
bd57a74
to
3351740
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This was split off from #346043. It updates
overrideLibcxxto usetapito restrict symbols and updates LLVM to always apply the adapter on Darwin. This aligns Darwin’s behavior regarding LLVM with Linux, which always uses libstdc++ unless you use llvmPackages.libcxxStdenv.Whether to apply this to pkgsLLVM is an open question. It makes sense to do that there as well.
Things done
nix.conf? (See Nix manual)sandbox = relaxedsandbox = truenix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage./result/bin/)Add a 👍 reaction to pull requests you find important.