JakeHillion/nixpkgs
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

clang: don't set -march for overridden target

Browse Source 
If -target is explicitly passed to clang, we shouldn't pass our -march
value for the default target, because it probably won't exist for the
target being used.  Up until now, clang has been lenient with this,
but it's a hard error with clang 17, so since gcc.arch is always set
on aarch64, fixing this is a hard requirement for upgrading our
default clang to 17.

Before (with clang 17 on aarch64-linux):

	$ clang -target bpf -c -o /dev/null test.bpf.c
	clang: warning: ignoring '-fstack-protector-strong' option as it is not currently supported for target 'bpf' [-Woption-ignored]
	clang: error: unsupported option '-march=' for target 'bpf'
	clang: warning: argument unused during compilation: '--gcc-toolchain=/nix/store/cngak08nb1yk44gnjipv5rg1ahh1xkax-gcc-13.2.0' [-Wunused-command-line-argument]

After:

	$ clang -target bpf -c -o /dev/null test.bpf.c
	clang: warning: ignoring '-fstack-protector-strong' option as it is not currently supported for target 'bpf' [-Woption-ignored]
	clang: warning: argument unused during compilation: '--gcc-toolchain=/nix/store/cngak08nb1yk44gnjipv5rg1ahh1xkax-gcc-13.2.0' [-Wunused-command-line-argument]
This commit is contained in:
Alyssa Ross 2024-02-27 19:30:29 +01:00
parent 269ce7215b
commit 12b0e8ac74
No known key found for this signature in database
GPG Key ID: F9DBED4859B271C0
2 changed files with 9 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
pkgs/build-support/cc-wrapper/add-clang-cc-cflags-before.sh
View File

@ -7,5 +7,5 @@ for p in "${params[@]}"; do
done
if $needsTarget; then
extraBefore+=(-target @defaultTarget@)
extraBefore+=(-target @defaultTarget@ @march@)
fi

9
pkgs/build-support/cc-wrapper/default.nix
View File

@ -595,8 +595,11 @@ stdenv.mkDerivation {
# Always add -march based on cpu in triple. Sometimes there is a
# discrepency (x86_64 vs. x86-64), so we provide an "arch" arg in
# that case.
#
# For clang, this is handled in add-clang-cc-cflags-before.sh
# TODO: aarch64-darwin has mcpu incompatible with gcc
+ optionalString ((targetPlatform ? gcc.arch) && (isClang || !(stdenv.isDarwin && stdenv.isAarch64)) &&
+ optionalString ((targetPlatform ? gcc.arch) && !isClang && !(stdenv.isDarwin && stdenv.isAarch64) &&
isGccArchSupported targetPlatform.gcc.arch) ''
echo "-march=${targetPlatform.gcc.arch}" >> $out/nix-support/cc-cflags-before
''
@ -685,6 +688,10 @@ stdenv.mkDerivation {
## Needs to go after ^ because the for loop eats \n and makes this file an invalid script
##
+ optionalString isClang ''
# Escape twice: once for this script, once for the one it gets substituted into.
export march=${lib.escapeShellArg
(lib.optionalString (targetPlatform ? gcc.arch)
(lib.escapeShellArg "-march=${targetPlatform.gcc.arch}"))}
export defaultTarget=${targetPlatform.config}
substituteAll ${./add-clang-cc-cflags-before.sh} $out/nix-support/add-local-cc-cflags-before.sh
''