llvmPackages_*.clang should check the default compiler for the package
set it is targeting (targetPackages.stdenv.cc) instead of the compiler
that has been used to build it (stdenv.cc) in order to get some sense of
whether to use libc++ or libstdc++.
Since we are now inspecting targetPackages in the llvmPackages.clang
attribute, we need to avoid using it in the cross stdenv — which just
forces us to explicitly request libcxxClang for darwin instead of
relying on the clang attribute to pick it for us.
We also need to do something similar for targetPackages.stdenv.cc: Here
the llvmPackages.clang logic would work as we want (inspect
targetPackages.stdenv.cc and if it doesn't exist, make the choice based
on stdenv.cc), but it gets locked in a cycle with the previous package.
We can easily break this, however: We know that the previous set had
clang and the next one doesn't exist, so we'd choose libcxxClang any day
of the week.
LLVM 12 added the memory profiling runtime and LLVM 13 the ORC
runtime. Both need a libc in order to build (or at least headers not
present in clang's resource root), so we'll disable them for any sort of
baremetal-ish build. memprof likely doesn't work in a baremetal
situation at all, orc is unknown. Whether both would compile with musl
is to be checked.
LLVM 11 libcxxabi has some flags to support usage in the Darwin stdenv,
in particular, `standalone` and `withLibunwind`.
Darwin stdenv needs the `standalone` flag because its `hostPlatform` set
doesn't have `useLLVM` set to true. And it needs `withLibunwind` to
explicitly disable including `libunwind` as a build input.
We also prefix `install_name_tool` in case we're cross-compiling.
This is already done for previous versions of clang which use
a release tarball, but must be done differently for the more
recent versions which use fetchFromGitHub.
Fixes clang-tools clangd wrapper
Commit 199b7c50 "compiler-rt: remove <cyclades.h> from libsanitizer"
broke conditional conditional musl patches.
The change has a few effects:
- pkgsStatic.llvmPackages_{5,6,7}.compiler-rt: fix build on musl after cyclades backport
- pkgsStatic.llvmPackages_{{5..13},git}.compiler-rt: drop incomplete musl patches as
sanitizers are disabled anyway and require more upstream porting.
the fix to extendDerivation in #140051 unwittingly worsened eval performance by
quite a bit. set elements alone needed over 1GB extra after the change, which
seems disproportionate to how small it was. if we flip the logic used to
determine which outputs to install around and keep a "this one exactly" flag in
the specific outputs instead of a "all of them" in the root we can avoid most
of that cost.
To avoid unnecessary builds but this needs to be fixed ASAP. Chromium
already depends on it and a lot of additional packages, including Mesa,
will depend on it after the stable release.
