GPRbuild is a multi language build system developed by AdaCore which
is mostly used for build Ada-related projects using GNAT.
Since GPRbuild is used to build itself and its dependency library
XML/Ada we first build a bootstrap version of it using the provided
bash build script bootstrap.sh as the gprbuild-boot derivation.
gprbuild-boot is then used to build xmlada and the proper gprbuild
derivation.
GPRbuild has its own search path mechanism via GPR_PROJECT_PATH which
we address via a setupHook. It currently works quite similar to the
pkg-config one: It accumulates all inputs into GPR_PROJECT_PATH,
GPR_PROJECT_PATH_FOR_BUILD etc. However this is quite limited at the
moment as we don't have a gprbuild wrapper yet which understands the
_FOR_BUILD suffix. However, we'll need to address this in the future
as it is currently basically impossible to test since the distinction
only affects cross-compilation, but it is not possible to build a GNAT
cross-compiler in nixpkgs at the moment (I'm working on changing that,
however).
Another issue we had to solve was GPRbuild not finding the right GNAT
via its gprconfig tool: GPRbuild has a knowledge base with compiler
definitions which run some checks and collect info about binaries
which are in PATH. In the end the first compiler in PATH that supports
the desired language is selected.
We want GPRbuild to discover our wrapped GNAT since the unwrapped one
is incapable of producing working binaries since it won't find the
crt*.o objects distributed with libc. GPRbuild however needs to find
the Ada runtime distributed with GNAT which is not part of the wrapper
derivation, so it will skip the wrapper and select the unwrapped GNAT.
Symlinking the unwrapped's lib directory into the wrapper fixes this
problem, but breaks linking in some cases (e. g. when linking against
OMP from gcc, the runtime variant will shadow the problem dynamic lib
from buildInputs). Additionally it uses gnatls as an indicator it has
found GNAT which is not part of the wrapper.
The solution we opted to adopt here is to install a custom compiler
description into gprbuild's knowledge base which properly detects the
nixpkgs GNAT wrapper: It uses gnatmake to detect GNAT instead of
gnatls and discovers the runtime via a symlink we add to
`$out/nix-support`. This additional definition is enough to properly
detect GNAT, since the plain wrapped gcc detection works out of the
box. It may, however, be necessary to add special definitions for
other languages in the future where gprbuild also needs to discover
the runtime.
One future improvement would be to install libgpr into a separate
output or split it into a separate derivation (which would require to
link gprbuild statically always since otherwise we end up with a
cyclical dependency).
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>
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.
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)`
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.
The check for including the C++ standard library headers was nested inside the
check for linking with the C++ standard library. As a result, the `-nostdlib`
flag incorrectly implied `-nostdinc++`, which made it virtually impossible to
partially link C++ objects.
Fixes build failures with clang:
clang-7: error: unknown argument: '-fPIC -target'
clang-7: error: no such file or directory: '@<(printf %qn -O2'
clang-7: error: no such file or directory: 'x86_64-apple-darwin'
Introduced by 60c5cf9cea in #112449
The `platform` field is pointless nesting: it's just stuff that happens
to be defined together, and that should be an implementation detail.
This instead makes `linux-kernel` and `gcc` top level fields in platform
configs. They join `rustc` there [all are optional], which was put there
and not in `platform` in anticipation of a change like this.
`linux-kernel.arch` in particular also becomes `linuxArch`, to match the
other `*Arch`es.
The next step after is this to combine the *specific* machines from
`lib.systems.platforms` with `lib.systems.examples`, keeping just the
"multiplatform" ones for defaulting.
When invoking a simple Ada program with `gcc` from `gnats10`, the
following warnings are shown:
```
$ gcc -c conftest.adb
gnat1: warning: command-line option ‘-Wformat=1’ is valid for C/C++/ObjC/ObjC++ but not for Ada
gnat1: warning: command-line option ‘-Wformat-security’ is valid for C/C++/ObjC/ObjC++ but not for Ada
gnat1: warning: ‘-Werror=’ argument ‘-Werror=format-security’ is not valid for Ada
$ echo $?
0
```
This is only spammy when compiling Ada programs inside a Nix derivation,
but certain configure scripts (such as the ./configure script from the
gcc that's built by coreboot's `make crossgcc` command) fail entirely
when getting that warning output.
https://nixos.wiki/wiki/Coreboot currently suggests manually running
> NIX_HARDENING_ENABLE="${NIX_HARDENING_ENABLE/ format/}" make crossgcc
… but actually teaching the nixpkgs-provided cc wrapper that `format`
isn't supported as a hardening flag seems to be the more canonical way
to do this in nixpgks.
After this, Ada programs still compile:
```
$ gcc -c conftest.adb
$ echo $?
0
```
And the compiler output is empty.
We need to set FC so that CMake and other tools can find the fortran
compiler. Also we need to limit the hardening flags since fortify and
format don’t work with fortran.
Fixes#88449
