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
parent 44f09ccabf
commit 6605fadc68
4 changed files with 100 additions and 5 deletions
@@ -0,0 +1,70 @@
+# 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