nixpkgs/pkgs/build-support/bintools-wrapper/add-darwin-ldflags-before.sh
Andrew Childs 6605fadc68 bintools-wrapper: default platform versions for darwin
Instead of always supplying flags, apply the flags as defaults. Use
clang's native flags instead of lifting the linker flags from binutils
with `-Wl,`.

If a project is using clang to drive linking, make clang do the right
thing with MACOSX_DEPLOYMENT_TARGET. This can be overridden by command
line arguments. This will cause modern clang to pass
`-platform_version 10.12 0.0.0`, since it doesn't know about the SDK
settings. Older versions of clang will pass down `-macos_version_min`
flags with no sdk version.

At the linker layer, apply a default value for anything left
ambiguous. If nothing is specified, pass a full
`-platform_version`. If only `-macos_version_min` is specified, then
lock down the sdk_version explicitly with `-sdk_version`. If a min
version and sdk version is passed, do nothing.
2021-04-11 09:47:09 +09:00

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# Unconditionally adding in platform version flags will result in warnings that
# will be treated as errors by some packages. Add any missing flags here.
# There are two things to be configured: the "platform version" (oldest
# supported version of macos, ios, etc), and the "sdk version".
#
# The modern way of configuring these is to use:
# -platform_version $platform $platform_version $sdk_version"
#
# The old way is still supported, and uses flags like:
# -${platform}_version_min $platform_version
# -sdk_version $sdk_version
#
# If both styles are specified ld will combine them. If multiple versions are
# specified for the same platform, ld will emit an error.
#
# The following adds flags for whichever properties have not already been
# provided.
havePlatformVersionFlag=
haveDarwinSDKVersion=
haveDarwinPlatformVersion=
n=0
nParams=${#params[@]}
while (( n < nParams )); do
p=${params[n]}
case "$p" in
# the current platform
-@darwinPlatform@_version_min)
haveDarwinPlatformVersion=1
;;
# legacy aliases
-macosx_version_min|-iphoneos_version_min|-iosmac_version_min|-uikitformac_version_min)
haveDarwinPlatformVersion=1
;;
-sdk_version)
haveDarwinSDKVersion=1
;;
-platform_version)
havePlatformVersionFlag=1
# If clang can't determine the sdk version it will pass 0.0.0. This
# has runtime effects so we override this to use the known sdk
# version.
if [ "${params[n+3]-}" = 0.0.0 ]; then
params[n+3]=@darwinSdkVersion@
fi
;;
esac
n=$((n + 1))
done
# If the caller has set -platform_version, trust they're doing the right thing.
# This will be the typical case for clang in nixpkgs.
if [ ! "$havePlatformVersionFlag" ]; then
if [ ! "$haveDarwinSDKVersion" ] && [ ! "$haveDarwinPlatformVersion" ]; then
# Nothing provided. Use the modern "-platform_version" to set both.
extraBefore+=(-platform_version @darwinPlatform@ @darwinMinVersion@ @darwinSdkVersion@)
elif [ ! "$haveDarwinSDKVersion" ]; then
# Add missing sdk version
extraBefore+=(-sdk_version @darwinSdkVersion@)
elif [ ! "$haveDarwinPlatformVersion" ]; then
# Add missing platform version
extraBefore+=(-@darwinPlatform@_version_min @darwinMinVersion@)
fi
fi