Hello Galder,
At Oracle we use this script to generate new devkits every time we
update the toolchains we use for official builds, so it should be up to
date and working for the latest toolchain we use at least, which at this
time is Xcode 15.4. We have not yet jumped to Xcode 26, but when we do,
we will make the script work unless someone else beats us to it.
The expectation when running the script should not be to first have to
copy things around in the installation directory of Xcode. The script
should handle this automatically. However, it could be that we need to
supply a path to both Xcode and metal going forward. I have not looked
into this at all yet.
/Erik
On 11/27/25 04:20, Galder Zamarreno wrote:
Hi,
I'm wondering what's the objective of the Mac devkit and how much is it
being kept up to date.
I've been finding it useful to create a devkit that works for me to
build the jdk inside a Nix shell on a mac. Nix shells easily allow me to
capture all the dependencies building jdks have (e.g. capstone) in a
reproducable way independent of global installations at the mac level.
With the latest XCode 26 and Metal separation, I've been finding that
the current mac devkit is not fully suited for this changes.
As you might have seen in [1], Metal is no longer part of XCode 26 and
now needs to be installed separately. The location where Metal gets
installed by default is not inside /Applications/XCode.app but a rather
different place. On my system this is:
```
% xcrun --find metallib
/var/run/com.apple.security.cryptexd/mnt/com.apple.MobileAsset.MetalToolchain-v17.2.54.0.mgWMUd/Metal.xctoolchain/usr/bin/metallib
```
To be able to carry on building the JDK on a Nix shell, I manually moved
the Metal.xctoolchain folder to
/Applications/Xcode.app/Contents/Developer/Toolchains and then invoked
the mac devkit script.
This alone however was not enough to get the jdk to build, but the XCode
26 itself does have the `metal` executable and the jdk was picking it
up. So, on top of that manual move, I tweaked the
`DEVKIT_TOOLCHAIN_PATH` so that the Metal binaries would resolve out of
the Metal.xctoolchain/usr/bin folder:
```
echo-info
"DEVKIT_TOOLCHAIN_PATH=\"\$DEVKIT_ROOT/Xcode/Contents/Developer/Toolchains/Metal.xctoolchain/usr/bin:\$DEVKIT_ROOT/Xcode/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin:\$DEVKIT_ROOT/Xcode/Contents/Developer/usr/bin\""
```
After doing this I rebuilt the devkit and I was able to build the jdk
once again inside a Nix shell on mac.
Of course, the devkit could have been modified to avoid the need for the
manual move and instead resolve the `/var/run/...` folder. But I do
wonder how much this devkit really is kept up to date and what's the use
case that ended up creating it.
Thanks
Galder
[1] https://bugs.openjdk.org/browse/JDK-8372393
[2]
https://medium.com/%40sergey-pekar/how-to-fix-annoying-xcode-26-not-building-swiftui-previews-error-cannot-execute-tool-metal-due-49564e20357c
--
Galder Zamarreño
Software Developer
IBM Software
[email protected]
IBM
