Example with `clangUseLLVM` which is the default when using `useLLVM`
```nix
config.replaceCrossStdenv = { buildPackages, baseStdenv }:
if baseStdenv.targetPlatform.useLLVM or false
then (buildPackages.stdenvAdapters.overrideCC baseStdenv buildPackages.llvmPackages_16.clangUseLLVM)
else baseStdenv;
```
The conditional necessary, otherwise the other sets(such as `pkgsCross.aarch64-multiplatform.llvmPackages`)
without `useLLVM` will use the stdenv without the necessary conditions to avoid infinite
recursion because of [targetLlvmLibraries](644b234e1c/pkgs/development/compilers/llvm/16/default.nix (L208))
usage.
[`replaceStdenv` is not used when cross-compiling](d77bda728d/pkgs/stdenv/cross/default.nix (L12-L13))
`replaceStdenv` uses an additional stage to replace the stdenv to avoid
infinite recursion and other issues but that should not be necessary for cross.
Since 97c43828fb the `file` package has
been part of stdenv, and no longer needs to be listed explicitly as a
build input. Let's remove the platform-specific inclusion for mingw64
as suggested by @mehmooda:
https://github.com/NixOS/nixpkgs/pull/168413#issuecomment-1147370500
I traced the line removed by this commit through the `git blame`; it
was initially added in this commit (and then shuffled around a few
dozen times by refactorings):
8b292a1b35
The commit message indicates that `libpng-1.6.20` was current at the
time. Although there are [libpng
archives](https://github.com/glennrp/libpng) available in git form,
the older versions don't have their autoconfery vendored in, so I
can't link to them. Fortunately the relevant bit hasn't changed since
then:
a37d483651/configure (L5575)
```
mingw* | pw32*)
# Base MSYS/MinGW do not provide the 'file' command needed by
# func_win32_libid shell function, so use a weaker test based on 'objdump',
# unless we find 'file', for example because we are cross-compiling.
if ( file / ) >/dev/null 2>&1; then
lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
lt_cv_file_magic_cmd='func_win32_libid'
else
# Keep this pattern in sync with the one in func_win32_libid.
lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)'
lt_cv_file_magic_cmd='$OBJDUMP -f'
fi
;;
```
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.
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>
Update gnu-config (config.sub, config.guess) to suport the Genode
platform and apply the updateAutotoolsGnuConfigScriptsHook to Genode
cross-compilation.
Adds pkgsCross.wasm32 and pkgsCross.wasm64. Use it to build Nixpkgs
with a WebAssembly toolchain.
stdenv/cross: use static overlay on isWasm
isWasm doesn’t make sense dynamically linked.
this adds libc++ to the LLVM cross, giving us access to the full
Nixpkgs set. This requires 4 stages of wrapped compilers:
- Clang with no libraries
- Clang with just compiler-rt
- Clang with Libc, and compiler-rt
- Clang with Libc++, Libc, and compiler-rt
New android ndk (18) now uses clang. We were going through the wrapper
that are provided. This lead to surprising errors when building.
Ideally we could use the llvm linker as well, but this leads to errors
as many packages don’t support the llvm linker.
You can build (partially) with LLVM toolchain using the useLLVM flag.
This works like so:
nix-build -A hello --arg crossSystem '{ system =
"aarch64-unknown-linux-musl"; useLLVM = true }'
also don’t separate debug info in lldClang
It doesn’t work currently with that setup hook. Missing build-id?
crossOverlays only apply to the packages being built, not the build
packages. It is useful when you don’t care what is used to build your
packages, just what is being built. The idea relies heavily on the
cross compiling infrastructure. Using this implies that we need to
create a cross stdenv.
/cc @Ericson2314
PR was https://github.com/NixOS/nixpkgs/pull/46857
This line broke MacOS cross compilation. paxctl cannot be built on
macOS. Maybe it can be fixed, but no reason to break things
unnecessarily.
Regardless, you definitely need to be more careful about backporting.
I think it’s fine to move fast and break things on master but
with release-18.09 we should be more careful. Something like more
automated testing for cross compilation would also be
helpful (hopefully even making it block).
(cherry picked from commit f9c4075873)
It wasn’t exactly clear which NDK you were using previously. This adds
an attribute to system that handles what version of the NDK we should
use when building things.
/cc @Ericson2314
Packages get --host and --target by default, but can explicitly request
any subset to be passed as needed. See docs for more info.
rustc: Avoid hash breakage by using the old (ignored)
dontSetConfigureCross when not cross building
See previous commit for what was done to `binutils` to make this
possible.
There were some uses of `forcedNativePackages` added. The
combination of overrides with that attribute is highly spooky: it's
often important that if an overridden package comes from it, the
replaced arguments for that package come from it. Long term this
package set and all the spookiness should be gone and irrelevant:
"Move along, nothing to see here!"
No hashes should be changed with this commit
Before all overrides were also pruned in the previous stage, now
only gcc and binutils are, because they alone care about about the
target platform. The rest of the overrides don't, so it's better to
preserve them in order to avoid spurious rebuilds.
This fixes the "sliding window" principle:
0. Run packages: build = native; host = foreign; target = foreign;
1. Build packages: build = native; host = native; target = foreign;
2. Vanilla packages: build = native; host = native; target = native;
3. Vanilla packages: build = native; host = native; target = native;
n+3. ...
Each stage's build dependencies are resolved against the previous stage,
and the "foreigns" are shifted accordingly. Vanilla packages alone are
built against themsevles, since there are no more "foreign"s to shift away.
Before, build packages' build dependencies were resolved against
themselves:
0. Run packages: build = native; host = foreign; target = foreign;
1. Build packages: build = native; host = native; target = foreign;
2. Build packages: build = native; host = native; target = foreign;
n+2. ...
This is wrong because that principle is violated by the target
platform staying foreign.
This will change the hashes of many build packages and run packages, but
that is OK. This is an unavoidable cost of fixing cross compiling.
The cross compilation docs have been updated to reflect this fix.
The long term goal is a big replace:
{ inherit system platform; } => buildPlatform
crossSystem => hostPlatform
stdenv.cross => targetPlatform
And additionally making sure each is defined even when not cross compiling.
This commit refactors the bootstrapping code along that vision, but leaves
the old identifiers with their null semantics in place so packages can be
modernized incrementally.
