We need this stuff to be available in lib so make-derivation.nix can
access it to construct the Meson cross file.
This has a couple of other advantages:
- It makes Rust less special. Now figuring out what Rust calls a
platform is the same as figuring out what Linux or QEMU call it.
- We can unify the schema used to define Rust targets, and the schema
used to access those values later. Just like you can set "config"
or "system" in a platform definition, and then access those same
keys on the elaborated platform, you can now set "rustcTarget" in
your crossSystem, and then access "stdenv.hostPlatform.rustcTarget"
in your code.
"rustcTarget", "rustcTargetSpec", "cargoShortTarget", and
"cargoEnvVarTarget" have the "rustc" and "cargo" prefixes because
these are not exposed to code by the compiler, and are not
standardized. The arch/os/etc. variables are all named to match the
forms in the Rust target spec JSON.
The new rust.target-family only takes a list, since we don't need to
worry about backwards compatibility when that name is used.
The old APIs are all still functional with no warning for now, so that
it's possible for external code to use a single API on both 23.05 and
23.11. We can introduce the warnings once 23.05 is EOL, and make them
hard errors when 23.11 is EOL.
Rust is not yet able to target the n32 ABI on mips64.
Let's add `isMips64n32` to the `meta.badPlatforms` of all
derivations created by buildRustCrate.
I use this to automatically detect which packages on my system can
be built for n32 (almost all of them) and build those using n32, and
the few packages (mainly those that depend on boost or rust) that
can't for n64.
Without this PR, unlike `RUST_LIB_BACKTRACE=1 cargo run` you won't
get line numbers in backtraces from binaries built with:
```
nix build -f Cargo.nix --arg release false
```
This PR fixes that.
Fixes linker errors while building build.rs where it tries to link libiconv but cannot find it.
Rust executable build for Darwin need libiconv, and indeed buildInputs already has this case handled.
So why is another change needed? Suppose we are cross compiling from Darwin (the build platform) to something else, and the package has a build.rs build script.
The build script is built for the build platform (Darwin) and is also a regular Rust executable, needing libiconv, but due to cross compilation (and strict deps) we need an extra nativeBuildInput.
Fixes#204051. I have tried this on the reproducer stated in the ticket.
```
[nix-develop]$ $(nix-build -I nixpkgs=/home/shana/programming/nixpkgs --no-out-link)/tests/foo
running 1 test
test check_module_name ... ok
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
```
There are two problems: first that we end up splitting on spaces in the
loop. Even when that is fixed, we still would split on spaces in the
`export` inside the loop. We need to guard against both.
Fixes#199298
Confirmed that it fixes the case mentioned in the ticket:
```console
[nix-develop]$ $(nix-build -I nixpkgs=/home/shana/programming/nixpkgs Cargo.nix -A rootCrate.build --no-out-link)/bin/nix-rustc-env-escape-repro
Expecting three words, got: first second third
```
I think this is going to cause a rebuild of every Rust package even if
they were unaffected, not much we can do here.
We are replicating one mechanism behind `-Z build-std`.
There isn't yet crate2nix support for this, but one can (and I do) add
the missing stdlib deps (for this feature to pick up) with overrides.
With Rust 1.61, it is necessary to link to external static/dynamic libaries
when building the rlib that uses them, rather than when linking the final
binary. In fact, it is no longer necessary to specify the libraries to link
when building the final binary, but the library search path flags must still
be included.
This parameter is being set to `$NIX_BUILD_CORES` by default. This is a
standard practice but there's a suspicion that this can produce broken
builds. For some details see
https://github.com/cargo2nix/cargo2nix/issues/184 . As a
work-around/test, it'd be good if codegen-units can be set to something
constant, such as `1`. This PR allows it.
Note that the default of `$NIX_BUILD_CORES` is preserved so this MR
causes no change in default behaviour and no rebuilds.
These features are internal-only, have special characters that bash
doesn't support in variable names, and aren't normally given
environment variables by cargo as far as I can tell.
According to rustc implementation[1], `-C incremental=no` enables
incremental builds with directory name `no`. This patch removes the
`-C incremental` argument to disable incremental builds.
[1]: ee86f96ba1/compiler/rustc_session/src/options.rs (L918-L919)
As @lopsided98 points out in #105305, since the hashes are now target
sensative, and until we find reason to actually care to test what they
are exactly, we are best just normalizing them away in the tests.
Bofore this change, NUM_JOBS was set to 1. Some crates for building
C/C++ code (e.g. the cc and cmake crates), rely on this variable to
set the number of jobs. As a consequence, we were compiling embedded
libraries serially. Change this to NIX_BUILD_CORES to permit parallel
builds.
Prior discussion:
https://github.com/NixOS/nixpkgs/pull/50452#issuecomment-439407547
