Compiling for Catalyst

[niklassaers]

Hi,
I'm trying to compile for Catalyst, and the way I try doing that is through making an .xcframework. So I tried the following:

sh iSSH2.sh --platform=macosx --archs="x86_64" # i386 no longer supported on 10.15
sh iSSH2.sh --platform=iphoneos --min-version=13.0

xcodebuild -create-xcframework \
-library libssh2_macosx/lib/libssh2.a -headers libssh2_macosx/include \
-library libssh2_iphoneos/lib/libssh2.a -headers libssh2_iphoneos/include \
-output libssh2.xcframework

But that gave me:
"error: binaries with multiple platforms are not supported 'libssh2_iphoneos/lib/libssh2.a'"

So I compiled x86_64 and arm64+arm64e separately

sh iSSH2.sh --platform=macosx --archs="x86_64"
sh iSSH2.sh --platform=iphoneos --min-version=13.0 --archs="arm64 arm64e"
mv libssh2_iphoneos libssh2_iphoneos_arm64_arm64e
sh iSSH2.sh --platform=iphoneos --min-version=13.0 --archs="x86_64"
mv libssh2_iphoneos libssh2_iphoneos_x86_64

xcodebuild -create-xcframework \
-library libssh2_macosx/lib/libssh2.a -headers libssh2_macosx/include \
-library libssh2_iphoneos_x86_64/lib/libssh2.a -headers libssh2_iphoneos_x86_64/include \
-library libssh2_iphoneos_arm64_arm64e/lib/libssh2.a -headers libssh2_iphoneos_arm64_arm64e/include \
-output libssh2.xcframework 

but that gave me a new error:
"error: unable to find any architecture information in the binary at 'libssh2_iphoneos_arm64_arm64e/lib/libssh2.a'"

Even splitting arm64 and arm64e into binaries for just them, or only include arm64 or arm64e themselves, gave me the same error. Why won't it find architecture information?

Not including arm64 and arm64e at all, however, gave me success:
"xcframework successfully written out to: libssh2.xcframework"

But obviously, I'd like a framework with arm64 and arm64e support. :-)

Any input on how to proceed from here? Would be really good to be able to build this for Mac Catalyst

[niklassaers]

(of course, I could be heading down the entirely wrong path here. If I only compile OpenSSL using marcelosalloum/OpenSSL-for-iPhone with targets "ios-sim-cross-i386 ios64-cross-arm64 ios-cross-armv7s ios-cross-armv7 mac-catalyst-x86_64", they import just fine. But, of course, I need libssh2 too)

[Jan-E]

It may be my lack of knowledge of Catalyst, but is not the only architecture you need for Catalyst on OSX 10.15 x86_64?

tfr@TFRs-Mac iSSH2 % ./iSSH2.sh --platform=iphoneos --min-version=8.0 --archs="x86_64"             
Initializing...

Libssh2 version: 1.9.0 (Automatically detected)
OpenSSL version: 1.1.1d (Automatically detected)
SDK version: 13.2 (Automatically detected)
Architectures: x86_64 
Platform: iphoneos
Platform min version: 8.0

Downloading openssl-1.1.1d.tar.gz
############################################################################################# 100.0%
MD5: 3be209000dbc7e1b95bcdf47980a3baa
Extracting openssl-1.1.1d.tar.gz
Building OpenSSL 1.1.1d, please wait...
- iPhoneSimulator x86_64 done!
Building libssl.a fat library...
Building libcrypto.a fat library...
Copying headers...
Building done.
Downloading libssh2-1.9.0.tar.gz
############################################################################################# 100.0%############################################################################################# 100.0%
MD5: 1beefafe8963982adc84b408b2959927
Extracting libssh2-1.9.0.tar.gz
Building Libssh2 1.9.0:
- iPhoneSimulator x86_64 done!
Building libssh2.a fat library...
Copying headers...
Building done.
Cleaning up temporary files...
tfr@TFRs-Mac iSSH2 % xcodebuild -create-xcframework \
-library libssh2_macosx/lib/libssh2.a -headers libssh2_macosx/include \
-library libssh2_iphoneos/lib/libssh2.a -headers libssh2_iphoneos/include \
-output libssh2.xcframework
xcframework successfully written out to: /Users/tfr/Documents/iSSH2/libssh2.xcframework

[Jan-E]

Or could you just use the libssh2 for macOS for a Catalyst app?

[niklassaers]

Hi @Jan-E ,
Thanks for your input. Making a framework with only the simulator part (--platform=iphoneos --archs="x86_64") and macOS part makes the iOS binary that is dependent on arm64 not able to compile. In Xcode it shows me the following error: "While building for Mac Catalyst, no library for this platform was found in 'libssh2.xcframework'."

I've tried embedding separate libssh2.a files for arm64 and for macOS, but I keep getting "Building for Mac Catalyst, but the linked library 'libssh2.a' was built for iOS + iOS Simulator. You may need to restrict the platforms for which this library should be linked in the target editor, or replace it with an XCFramework that supports both platforms."

Lipo'ing them together into one gave the added trouble that both the simulator and macOS versions were x86_64, and removing the simulator part got me back to the error above. So apparently x86_64 in the simulator and x86_64 on macOS is not the same in its eyes. That's why I brought up the targets from the OpenSSL-for-iPhone project above: "ios-sim-cross-i386 ios64-cross-arm64 ios-cross-armv7s ios-cross-armv7 mac-catalyst-x86_64". Compiling it gives me static libraries, no .xcframework, and those static libraries just work. :-) So if we could only bring this to libssh2.a too, that should solve the problem too.

For the xcframework route - I tried adding the following to its Info.plist and copying the files into place myself, but alas I'm back at "While building for Mac Catalyst, no library for this platform was found in 'libssh2.xcframework'." The lines I added were

<dict>
  <key>HeadersPath</key>
  <string>Headers</string>
  <key>LibraryIdentifier</key>
  <string>ios-arm64</string>
  <key>LibraryPath</key>
  <string>libssh2.a</string>
  <key>SupportedArchitectures</key>
  <array>
    <string>arm64</string>
    <string>arm64e</string>
  </array>
  <key>SupportedPlatform</key>
  <string>ios</string>
</dict>

[Jan-E]

OK, clear. When I have got the time I'll experiment further, but for the moment I am out of ideas. Wishing you the best with your attempts.

[niklassaers]

I have made a demo catalyst app with OpenSSL integrated fine and the libssh2.a compiled as described above: https://github.com/niklassaers/DemoCatalyst

[Jan-E]

Getting closer. See Jan-E@4262507 and Jan-E@4262507#commitcomment-35983917 for a working example of building a MacCatalyst library of libssh2.

The trick of building for MacCatalyst is adding -target x86_64-apple-ios13.0-macabi to the CFLAGS. See the explanation in https://stackoverflow.com/a/56860199/872051 where I got the idea to solve this.

[Jan-E]

I tried to use these libs in a real iPad app:

Ignoring file Pods/NMSSH/NMSSH-iOS/Libraries/lib/libssh2.a, missing required architecture armv7 in file Pods/NMSSH/NMSSH-iOS/Libraries/lib/libssh2.a (1 slices)

Ergo, the other libs have to be added to the fat library as well.

[Jan-E]

Jan-E@5f233a1 brought me closer to compiling arm64 for Mac Catalyst.

Build command:

CFLAGS="-target arm64-apple-ios13.0-macabi" ./iSSH2.sh --platform=iphoneos --target=iphoneos --min-version=10.15 --archs="arm64"

The trick is to add -target arm64-apple-ios13.0-macabi to the CFLAGS in the Makefile's after the configure. This went fine up intil the linking of libSystem.tbd

libtool: link: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch arm64 -pipe -no-cpp-precomp -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS13.2.sdk -target arm64-apple-ios13.0-macabi -miphoneos-version-min=10.15 -fembed-bitcode -DLIBSSH2_DARWIN -o ssh2 ssh2.o ../src/.libs/libssh2.a -L/Users/tfr/documents/iSSH2-Catalyst/openssl_iphoneos//lib -lssl -lcrypto

clang: warning: overriding '-miphoneos-version-min=10.15' option with '--target=arm64-apple-ios13.0-macabi' [-Woverriding-t-option]

ld: warning: ignoring file /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.0/lib/darwin/libclang_rt.osx.a, missing required architecture arm64 in file /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.0/lib/darwin/libclang_rt.osx.a (3 slices)

ld: building for Mac Catalyst, but linking in .tbd file (/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS13.2.sdk/usr/lib/libSystem.tbd) built for iOS, file '/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS13.2.sdk/usr/lib/libSystem.tbd' for architecture arm64

Where to find a libSystem.tbd, built for Mac Catalyst?? There are about 8 variants of libSystem.tbd in the Xcode.app. I tried the most likely ones, but none of hem worked.

The missing required architecture arm64 in libclang_rt.osx.a is worrying as well, but it is only a warning, not a fatal error.

[niklassaers]

Thanks a lot, @Jan-E , great find with the CFLAGS and thanks for explaining how to use them. I'll follow your lead here and see what I can find out

[Jan-E]

I think I have solved it with this commit: Jan-E@b9610a1

There is a script catalyst.sh in the repo now that builds OpenSSL 1.1.1d and LibSSH2 1.9.0 for Mac Catalyst. The idea was stolen from the OpenSSL for iPhone repo: build x86_64 for Mac Catalyst and all the others just for iOS and create a fat library with those libs. You cannot combine x86_64 for iOS and x86_64 for Mac Catalyst in the same fat library, so I went for the Mac Catalyst version.

% lipo -info ./openssl_iphoneos/lib/libssl.a                   
Architectures in the fat file: ./openssl_iphoneos/lib/libssl.a are: armv7 armv7s i386 x86_64 arm64 arm64e 

where x86_64 is the MacOSX version. I added those lib and the headers to https://github.com/Jan-E/DemoCatalyst/commits/master

[Jan-E]

FWIW: I tested the libs in a B2B iPad app: it uploaded 15.0 MB in 3.99 seconds. The iPad app uses the camera, so I will have to update a lot more to make it work on Mac Catalyst.

[niklassaers]

Wonderful, checking it out and will report back! :-)

[Jan-E]

The iOS simulator does not work:

ld: warning: building for iOS Simulator, but linking in object file (Pods/NMSSH/NMSSH-iOS/Libraries/lib/libcrypto.a(aes_cbc.o)) built for Mac Catalyst

In my main app that is no real problem, because I cannot test the camera either.