This reduces code duplication, makes the SDK variables available
earlier in the wrappers, and makes the behaviour between the two
wrappers more consistent.
It is unusual to invoke a wrapped compiler without setting
`DEVELOPER_DIR`, but it can happen when a user adds a compiler to their
installed packages or when a package intentionally invokes the compiler
without an environment (such as the GHC binary packages).
Some compilers may know to check these paths when `SDKROOT` is set, but
it’s not assumed they do. `SDKROOT` is instead derived from the
`DEVELOPER_DIR`, and `NIX_CFLAGS_COMPILE` is set up with the sysroot and
necessary framework and include search paths.
Before this commit, `pkgs/build-support/cc-wrapper/add-flags.sh`
was using `-B@out@/bin` instead of `-B@bintools@/bin`
to force `cc` to use `ld-wrapper.sh` when calling `ld`.
That was confusing `cc` when asked to print
the location of a library precisely named `c++`
because `-B` prefixes are also used by `cc` to find libraries,
see https://gcc.gnu.org/onlinedocs/gcc/Directory-Options.html#index-B
Indeed, instead of having `cc --print-file-name c++`
failing to found a `c++` library and just returning the given `c++` string
to let a linker resolve it thereafter,
it was finding that `@out@/bin/c++` executable,
mistaking it for a library and returning its absolute path,
forcing the linker to load an executable as a library.
Before this commit:
```console
$ nix run -f . stdenv.cc -- --print-file-name c++
/nix/store/9bv7dcvmfcjnmg5mnqwqlq2wxfn8d7yi-gcc-wrapper-13.2.0/bin/c++
```
After this commit:
```console
$ nix run -f . stdenv.cc -- --print-file-name c++
c++
```
Fixes https://gitlab.haskell.org/ghc/ghc/-/issues/23138#note_567034
where this behavior was breaking GHC on Darwin.
[Confirmed by @414owen](https://github.com/NixOS/nixpkgs/pull/317224#issuecomment-2171276177):
> This fixed all our haskell builds on Arm64 darwin, which were trying
> to link in clang++...
In https://github.com/NixOS/nixpkgs/issues/158042 I noticed order
mismatch as a bootstrap build failure when building x86_64-linux
against glibc-2.35 in nixpkgs (bootstrap libs has glibc-2.27):
expand-response-params> ld: /nix/store/p4s4jf7aq6v6z9iazll1aiqwb34aqxq9-bootstrap-tools/lib/crt1.o: in function `_start':
expand-response-params> /build/glibc-2.27/csu/../sysdeps/x86_64/start.S:101: undefined reference to `__libc_csu_fini'
expand-response-params> ld: /build/glibc-2.27/csu/../sysdeps/x86_64/start.S:102: undefined reference to `__libc_csu_init'
expand-response-params> collect2: error: ld returned 1 exit status
Here crt1.o from glibc-2.27 links against libc.so.6 from glibc-2.35.
This happens because ordering of `-L` (influences `libc.so` lookup) and
`-B` (influences `crt1.o` lookup) flags differs:
expand-response-params> -B/...-bootstrap-tools/lib
expand-response-params> -B/...-glibc-2.35/lib/
...
expand-response-params> -L/...-glibc-2.35/lib
expand-response-params> -L/...-bootstrap-tools/lib
The change makes consistent ordering of `-L`/`-B` and allows getting to
stage4 for `glibc-2.35` target.
In a typical build environment the toolchain will use the value of the
MACOSX_DEPLOYMENT_TARGET environment variable to determine the version
of macOS to support. When cross compiling there are two distinct
toolchains, but they will look at this single environment variable. To
avoid contamination, we always set the equivalent command line flag
which effectively disables the toolchain's internal handling.
Prior to this change, the MACOSX_DEPLOYMENT_TARGET variable was
ignored, and the toolchains always used the Nix platform
definition (`darwinMinVersion`) unless overridden with command line
arguments.
This change restores support for MACOSX_DEPLOYMENT_TARGET, and adds
nix-specific MACOSX_DEPLOYMENT_TARGET_FOR_BUILD and
MACOSX_DEPLOYMENT_TARGET_FOR_TARGET for cross compilation.
I hate the thing too even though I made it, and rather just get rid of
it. But we can't do that yet. In the meantime, this brings us more
inline with autoconf and will make it slightly easier for me to write a
pkg-config wrapper, which we need.
It is useful to make these dynamic and not bake them into gcc. This
means we don’t have to rebuild gcc to change these values. Instead, we
will pass cflags to gcc based on platform values. This was already
done hackily for android gcc (which is multi-target), but not for our
own gccs which are single target.
To accomplish this, we need to add a few things:
- add ‘arch’ to cpu
- add NIX_CFLAGS_COMPILE_BEFORE flag (goes before args)
- set -march everywhere
- set mcpu, mfpu, mmode, and mtune based on targetPlatform.gcc flags
cc-wrapper: only set -march when it is in the cpu type
Some architectures don’t have a good mapping of -march. For instance
POWER architecture doesn’t support the -march flag at all!
https://gcc.gnu.org/onlinedocs/gcc/RS_002f6000-and-PowerPC-Options.html#RS_002f6000-and-PowerPC-Options
Factor a bintools (i.e. binutils / cctools) wrapper out of cc-wrapper. While
only LD is wrapped, the setup hook defines environment variables on behalf of
other utilites.
This reverts commit 0a944b345e, reversing
changes made to 61733ed6cc.
I dislike these massive stdenv changes with unclear motivation,
especially when they involve gratuitous mass renames like NIX_CC ->
NIX_BINUTILS. The previous such rename (NIX_GCC -> NIX_CC) caused
months of pain, so let's not do that again.
This is basically a sed job, in preparation of the next commit. The
rules are more or less:
- s"NIX_(.._WRAPPER_)?([a-zA-Z0-9@]*)"NIX_\1@infixSalt@_\2"g
- except for non-cc-wrapper-specific vars like `NIX_DEBUG`
