Xcode 12 Build Error: LibTorch/install/lib/libpytorch_qnnpack.a , building for iOS, but linking in object file built for macOS

[vukovicnikola]

🐛 Bug

When building Pytorch's official iOS project (with Enable Bitcode set to No), Xcode 12 gives the linking error copied below.

To Reproduce

I'm following the iOS guide on this page: https://pytorch.org/mobile/ios/

Error:

ld: in /Users/nikola/Downloads/PytorchMobile/Pods/LibTorch/install/lib/libpytorch_qnnpack.a (8x8-aarch64-neon.S.o), building for iOS, but linking in object file built for macOS, file '/Users/nikola/Downloads/PytorchMobile/Pods/LibTorch/install/lib/libpytorch_qnnpack.a' for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Expected behavior

Expecting the build to complete like in the official documentation.

Environment

PyTorch version: 1.7.0a0+297c938
Is debug build: False
CUDA used to build PyTorch: None

OS: Mac OSX 10.15.6 (x86_64)
GCC version: Could not collect
Clang version: 11.0.3 (clang-1103.0.32.62)
CMake version: version 3.14.0

Python version: 3.7 (64-bit runtime)
Is CUDA available: False
CUDA runtime version: No CUDA
GPU models and configuration: No CUDA
Nvidia driver version: No CUDA
cuDNN version: No CUDA

Versions of relevant libraries:
[pip3] numpy==1.18.2
[conda] blas 1.0 mkl
[conda] mkl 2019.4 233
[conda] mkl-include 2020.2 260
[conda] mkl-service 2.3.0 py37hfbe908c_0
[conda] mkl_fft 1.0.15 py37h5e564d8_0
[conda] mkl_random 1.1.0 py37ha771720_0
[conda] msgpack-numpy 0.4.3.2 py37_0
[conda] numpy 1.18.2 pypi_0 pypi
[conda] numpy-base 1.18.1 py37h3304bdc_1
[conda] numpydoc 0.9.2 py_0
[conda] pytorch 1.6.0 py3.7_0 pytorch
[conda] torch 1.4.0 pypi_0 pypi
[conda] torchstat 0.0.7 pypi_0 pypi
[conda] torchvision 0.5.0 pypi_0 pypi

[superlyy]

same issue here

[pavlonadolynskyi]

same ...

[alex-dosa92]

I have the same issue

[tintifax89]

Same issue. Any solutions/workarounds?

[xiaoqiangsheng2016]

I have the same issue, but use Xcode11 is ok

[thezealousfool]

But we cannot use xcode 11 for iOS 14 app development. Right?

[xiaoqiangsheng2016]

But we cannot use xcode 11 for iOS 14 app development. Right?

YES, iOS14 need Xcode12. we use Xcode12, and remove libTorch, use opencv instead. prediction use coreml(mlmodel file)

[pavlonadolynskyi]

managed to compile entire library via xcode 12 and problem gone, but faced another issue I can't fix:

Undefined symbols for architecture arm64: "c10::impl::ExcludeDispatchKeyGuard::ExcludeDispatchKeyGuard(c10::DispatchKey)", referenced from:

[vukovicnikola]

Any updates on this? This is a breaking bug for anyone using iOS 14 i.e. anyone working on MacOS Big Sur

[xta0]

The issue was in CMake's version. Obviously, 3.14 doesn't work well with XCode 12. We just tried 3.18, it works fine. Anyway, the solution would be

1. upload a bug fix version to cocoapods - 1.6.1
2. If you guys can't wait, you can build the static libs from source. Make sure you're using the latest CMake (3.18).

[husthyc]

Now LibTorch 1.6.1 has been released. Please try pod repo update then pod install with your project (make sure the version number in your Podfile is NOT a FIXED "1.6.0". If it is, please use "~>1.6.0" or "1.6.1" as the version number).

[gchanan]

this looks like all the PRs have been merged to master, so closing.