libcxxClang still depends on cc wrapper's gccForLibs for libgcc which is
not available when useLLVM is set. In such cases we need to switch to
clangUseLLVM and (try) to use compiler-rt instead.
Resolves#153759: pkgsLLVM.llvmPackages.stdenv now correctly
clangUseLLVM as cc, allowing compilation to work as expected.
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.
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.
This will begin the process of breaking up the `useLLVM` monolith. That
is good in general, but I hope will be good for NetBSD and Darwin in
particular.
Co-authored-by: sterni <sternenseemann@systemli.org>
lld needs LLVM's libunwind for its headers. That libunwind is not part
of the tools scope in pkgs/development/compilers/llvm/12/default.nix,
which means that lld previously received libunwind from top-level pkgs
which of course doesn't have the required headers.
To resolve this pass libunwind from the libraries scope — platform
concerns don't really mattern as only libunwind.src is used.
libunwind was initially passed correctly, but that was removed in
e830db4320. This regression was likely
introduced accidentally.
The bintools argument received a wrapped version of tools.bintools which
is already wrapped. Wrapped bintools twice leads to users of lldClang
being unable to find the tools which are not wrapped like ar.
The main thing was using `llvm_meta` in all versions.
Secondarily:
- libunwindx7: Forgot to split outputs
- libcxx{,abi} 12: Forgot to apply output-splitting patches.
- simplify `useLLVM` stdenv-switching logic.
- openmp always gets its own directory
- Introduce `preLibcCrossHeaders` to bootstrap libgcc and compiler-rt
the same way.
- Organize LLVM bintools as `bintools{-unwrapped,,NoLibc}` for
consistency with GNU Binutils and Apple's cctools.
- Do Android changes for all `llvmPackages` for consistency.
- Improve the way the default GCC and LLVM versions are selected.
This PR adds a new aarch64 android toolchain, which leverages the
existing crossSystem infrastructure and LLVM builders to generate a
working toolchain with minimal prebuilt components.
The only thing that is prebuilt is the bionic libc. This is because it
is practically impossible to compile bionic outside of an AOSP tree. I
tried and failed, braver souls may prevail. For now I just grab the
relevant binaries from https://android.googlesource.com/.
I also grab the msm kernel sources from there to generate headers. I've
included a minor patch to the existing kernel-headers derivation in
order to expose an internal function.
Everything else, from binutils up, is using stock code. Many thanks to
@Ericson2314 for his help on this, and for building such a powerful
system in the first place!
One motivation for this is to be able to build a toolchain which will
work on an aarch64 linux machine. To my knowledge, there is no existing
toolchain for an aarch64-linux builder and an aarch64-android target.
Before, clang was able to find some headers with a relative path to the
`-B` flag pointing near the unwrapped clang binary. But with multiple
outputs that doesn't work, so we use a "resource directory" as it done
later in the bootstrap.
Also begin to start work on cross compilation, though that will have to
be finished later.
The patches are based on the first version of
https://reviews.llvm.org/D99484. It's very annoying to do the
back-porting but the review has uncovered nothing super major so I'm
fine sticking with what I've got.
Beyond making the outputs work, I also strove to re-sync the packages,
as they have been drifting pointlessly apart for some time.
----
Other misc notes, highly incomplete
- lvm-config-native and llvm-config are put in `dev` because they are
tools just for build time.
- Clang no longer has an lld dep. That was introduced in
db29857eb3, but if clang needs help
finding lld when it is used we should just pass it flags / put in the
resource dir. Providing it at build time increases critical path
length for no good reason.
----
A note on `nativeCC`:
`stdenv` takes tools from the previous stage, so:
1. `pkgsBuildBuild`: `(?1, x, x)`
2. `pkgsBuildBuild.stdenv.cc`: `(?0, ?1, x)`
while:
1. `pkgsBuildBuild`: `(?1, x, x)`
2. `pkgsBuildBuild.targetPackages`: `(x, x, ?2)`
3. `pkgsBuildBuild.targetPackages.stdenv.cc`: `(?1, x, x)`
This might be a bit debatable but upstream uses "xx" instead of "++"
when using it as identifier / in the code (file/directory names, build
scripts, website URLs, etc.) so we should probably too.
And at least the attribute name and pname will be consistent now.
