Dunno if this is correct, there's other `hostPlatform.isDarwin`
conditionals which may be wrong.
Leaving the other conditionals to swift maintainers or people who are
interested in swift cross-compilation
```
$ nix repl --file . --system aarch64-darwin
nix-repl> pkgsCross.aarch64-multiplatform.swift
«derivation /nix/store/kqbaqwdfc9g0yvkq4ffrlqspranprlmy-swift-wrapper-aarch64-unknown-linux-gnu-5.8.drv»
nix-repl> pkgsCross.aarch64-multiplatform.buildPackages.swift
error:
error: expected a string but found null: null
at /home/artturin/nixgits/my-nixpkgs/.worktree/2/pkgs/development/compilers/swift/compiler/default.nix:586:11:
585| #WATCHOS_SIMULATOR
586| }.${targetPlatform.darwinPlatform}}
| ^
587|
```
Background:
LLVM has some tools that run at build time. In native builds, these are
built as a part of the usual build, but in cross builds they need to
come from buildPackages.
In many scenarios this is a small problem because LLVM from
buildPackages is already available as a build; but if cross building a
version of LLVM which is not available (e.g. a new git commit of LLVM)
this results in two builds of LLVM and clang, one native and one for the
cross.
Full builds of LLVM are expensive; and unnecessary in this scenario. We
don't need a native LLVM, only a native copy of the tools which run at
build time. This is only tablegen and related tooling, which are cheap
to build.
Implementation-wise, we introduce a derivation llvmPackages.tblgen,
which specifies the tablegen targets which need to be built and has a
custom installPhase to copy them to the output.
A previous attempt in https://github.com/NixOS/nixpkgs/pull/359967
dropped the use of LLVM_TABLEGEN_EXE and friends on the grounds that
llvm can already cross build these things, but that is false since it's
necessary in that case to wire in a cross compiler. This PR avoids that
problem by allowing access to buildPackages.tblgen.
Signed-off-by: Peter Waller <p@pwaller.net>
After final improvements to the official formatter implementation,
this commit now performs the first treewide reformat of Nix files using it.
This is part of the implementation of RFC 166.
Only "inactive" files are reformatted, meaning only files that
aren't being touched by any PR with activity in the past 2 months.
This is to avoid conflicts for PRs that might soon be merged.
Later we can do a full treewide reformat to get the rest,
which should not cause as many conflicts.
A CI check has already been running for some time to ensure that new and
already-formatted files are formatted, so the files being reformatted here
should also stay formatted.
This commit was automatically created and can be verified using
nix-build a08b3a4d19.tar.gz \
--argstr baseRev b32a094368
result/bin/apply-formatting $NIXPKGS_PATH
After final improvements to the official formatter implementation,
this commit now performs the first treewide reformat of Nix files using it.
This is part of the implementation of RFC 166.
Only "inactive" files are reformatted, meaning only files that
aren't being touched by any PR with activity in the past 2 months.
This is to avoid conflicts for PRs that might soon be merged.
Later we can do a full treewide reformat to get the rest,
which should not cause as many conflicts.
A CI check has already been running for some time to ensure that new and
already-formatted files are formatted, so the files being reformatted here
should also stay formatted.
This commit was automatically created and can be verified using
nix-build a08b3a4d19.tar.gz \
--argstr baseRev 78e9caf153
result/bin/apply-formatting $NIXPKGS_PATH
Using ninja makes it consistent with the other llvm package builds, and
libclang is not necessary as a dependency.
Signed-off-by: Peter Waller <p@pwaller.net>
