When wrapping `clang` and using a `gccForLibs` whose `libgcc` is in
its own output (rather than the `lib` output), this commit will adds
`-L${gccForLibs.libgcc}/lib` to `cc-ldflags`.
If that flag is not added, `firefox` will fail to compile because it
invokes `clang-wrapper` with `-fuse-ld=lld` and passes `-lgcc_s` to
`lld`, but does not tell `lld` where to find `libgcc_s.so`. In that
situation, firefox will fail to link.
cc-wrapper has essentially two separate codepaths: the `gccForLibs`
codepath, used only by non-gcc (i.e. clang) compilers, and the
"other" codepath.
This PR allows non-clang compilers to opt-in to the `gccForLibs`
codepath (off by default). To allow this, a new parameter
`ccForLibs` is exposed, since it would be extremely confusing for
gcc to be able to use `gccForLibs` but not do so by default.
This reverts commit 8c80bd08b7e39229947d55104d1871f5066437d9
("build-support/cc-wrapper: pass in non-existent --sysroot= to untangle
from libc").
This change was good in spirit: we caught a few genuine problems with
`scons` based packages (`godot`, `fluxus`) and unexpected `-idirafter`
includes in various boot loadres (`ipxe`, wimboot`):
https://github.com/NixOS/nixpkgs/pull/210004#issuecomment-1407162693
Unfortunately `--sysroot=` also has a negative impact on libary search
order for DT_NEEDED libraries and RUNPATHs of linked libraries. This
unexpectedly broke `dmd`, `d-seams`, `llvmPackages_rocm.compiler-rt`).
An interesting case of unexpected breakage is `usbmuxd2` where the bug
exposed incomplete library move on `libstdc++fs` in `gcc`.
The library breakage is very non-intuitive (on top of already unusual
layout of `cc-wrapper` driver). Let's revert this change for now.
Once it lands we can undo `--sysroot=/` workarounds merged for
`staging-next`.
After https://github.com/NixOS/nixpkgs/pull/210004 `usbmuxd2` started
failing to build as:
usbmuxd2-unstable> .../ld: cannot find -lstdc++fs: No such file or directory
usbmuxd2-unstable> clang-11: error: linker command failed with exit code 1 (use -v to see invocation)
This started happening because #210004 exposed a long-standing bug in
`gcc` derivation: `cc.lib` is missing `libstdc++fs` library:
$ find $(nix-build --no-link -A stdenv.cc.cc.lib) | fgrep libstdc | unnix
/<<NIX>>/gcc-11.3.0-lib/lib/libstdc++fs.la
/<<NIX>>/gcc-11.3.0-lib/lib/libstdc++.la
/<<NIX>>/gcc-11.3.0-lib/lib/libstdc++.so.6.0.29
/<<NIX>>/gcc-11.3.0-lib/lib/libstdc++.so
/<<NIX>>/gcc-11.3.0-lib/lib/libstdc++.so.6
It was not moved from `cc.out` output:
$ find $(nix-build --no-link -A stdenv.cc.cc) | fgrep libstdc | unnix
/<<NIX>>/gcc-11.3.0/lib/libstdc++.a
/<<NIX>>/gcc-11.3.0/lib/libstdc++fs.a
This change adds `cc` library lookup path back to `staging-next` until
`gcc` is fixed.`
FreeBSD doesn't use LLVM's cxxabi implementation, for backwards
compatibility reasons. Software expects the libcxxrt API when
building on FreeBSD. This fixes the build of
pkgsCross.x86_64-freebsd.boost.
Gcc does not allow `-march=` on PowerPC:
https://gcc.gnu.org/onlinedocs/gcc-12.2.0/gcc/RS_002f6000-and-PowerPC-Options.html#RS_002f6000-and-PowerPC-Options
Instead, `-mcpu=` should be used to set the minimum instruction set
and `-mtune=` is used to optimize instruction scheduling for a
specific processor. Both flags take the same set of valid values,
which includes `native`.
This commit causes `isGccArchSupported` to return `false` for PowerPC
targets so we never pass an `-march=` flag, since that will always be
rejected by gcc.
I would like to add an extra `gcc` build step during linux bootstrap
(https://github.com/NixOS/nixpkgs/issues/208412). This makes it early
bootstrap compiler linked and targeted against `bootstrapTools` `glibc`
including it's headers.
Without this change `gcc`'s spec files always prefer `bootstrapTools` `glibc`
for header search path (passed in as --with-native-system-header-dir=). We'can't
override it with:
- `-I` option as it gets stacked before gcc-specific headers, we need to keep
glibc headers after gcc as gcc cleans namespace up for C standard by using
#include_next and by undefining system macros.
- `-idirafter` option as it gets appended after existing `glibc`-includes
This `--sysroot=/nix/store/does/not/exist` hack allows us to remove existing
`glibc` headers and add new ones with `-idirafter`.
We use `cc-cflags-before` instead of `libc-cflags` to allow user to define
their own `--sysroot=` (like `firefox` does).
To keep it working prerequisite cross-symlink in gcc.libs is required:
https://github.com/NixOS/nixpkgs/pull/209153
Switches that gnatmake needs to pass to gcc must be given as
"-cargs <gcc_switches>" after at least the files to compile (see the
gnatmake docs for all the subtleties). This commit makes that happen,
in a way that triggers rebuilds only for things that actually depend on
GNAT, and not the other compilers contained in GCC.
On darwin clang driver always sets -D_FORTIFY_SOURCE=0 under asan.
This causes -Werror to trip over macro redefinition:
<command line>:1:9: error: '_FORTIFY_SOURCE' macro redefined [-Werror,-Wmacro-redefined]
#define _FORTIFY_SOURCE 2
^
To avoid it let's always explicitly undefine it first before redefining.
There is context here that I needed when resolving an issue in which
libc was added to NIX_CFLAGS_COMPILE before the C++ stdlib that took
me awhile to understand.
It was suggested to me that this context be included as a comment,
since it is not obvious and could help others in the future.
POSIX sh (and `bash`) impose a restriction on environment variable name
format and disallow hypheps in the names. Normally it's not a problem
as nothing usually tries to refer nyphenated names.
One exception is `nix develop` (https://github.com/NixOS/nix/issues/6848):
$ nix develop -f. gcc -L
gcc-wrapper> ...-get-env.sh: line 70: expand-response-params: bad substitution
Note that bash usually uses explicitly created `expandResponseParams`
variant of the same variable.
To work the problem around let's avoid environment variable export and move
it to `passthru` for `cc` (used ina few places) and remove it completely for
`binutils` (does not seem to be used at all).
Noticed this bug when was trying to bootstrap m4 on darwin. That fixes
line 163: no such file or directory error
That does not solve all problems staging has on darwin.
This enables users to make use of clang's multi-platform/target support
without having to go through full cross system setup. This is especially useful
for generating bpf object files, I'm not even usre what would a no-userland
cross compile system tuple even look like to even try going that route.
Fixes#176128
